,transcriber's ,notes ,obvious typographical errors have been silently corrected4 ,variations in hyphenation other spelling and punctuation remains unchanged4 ,in particular the words height and hight are used about equally4 ,as hight is a legitimate spelling1 it has not been changed4 ,some of the larger tables have been re-organised to improve clarity and avoid excessive width4 ,the footnotes are located at the end of the book4 ,italics are represented thus italic4 ,,lead ,,smelting ,,and ,,refining ,,with ,,some ,,notes ,,on ,,lead ,,mining ,,edited ,,by ,,walter ,,renton ,,ingalls ,illustration3 ,publisher's ,device ,,new ,,york ,,and ,,london ,,the ,,engineering ,,and ,,mining ,,journal #aijf ,,copyright1 #aijf1 ,,by ,,the ,,engineering ,,and ,,mining ,,journal4 ,,also ,,entered ,,at ,,stationers' ,,hall1 ,,london1 ,,england4 ,,all ,,rights ,,reserved4 ,,preface ,this book is a reprint of various articles pertaining especially to the smelting and refining of lead1 together with a few articles relating to the mining of lead ore1 which have appeared in the ,engineering and ,mining ,journal1 chiefly during the last three years2 in a few cases articles from earlier issues have been inserted1 in view of their special importance in rounding out certain of the subjects treated4 ,for the same reason1 several articles from the ,transactions of the ,american ,institute of ,mining ,engineers have been incorporated1 permission to republish them in this way having been courteously granted by the ,secretary of the ,institute4 ,certain of the other articles comprised in this book are abstracts of papers originally presented before engineering societies1 or published in other technical periodicals1 subsequently republished in the ,engineering and ,mining ,journal1 as to which proper acknowledgment has been made in all cases4 ,the articles comprised in this book relate to a variety of subjects1 which are of importance in the practical metallurgy of lead1 and especially in connection with the desulphurization of galena1 which is now accomplished by a new class of processes known as 8,lime ,roasting0 processes4 ,the successful introduction of these processes into the metallurgy of lead has been one of the most important features in the history of the latter during the last twenty-five years4 ,their development is so recent that they are not elsewhere treated in technical literature1 outside of the pages of the periodicals and the transactions of engineering societies4 ,the theory and practice of these processes are not yet by any means well understood1 and a year or two hence we shall doubtless possess much more knowledge concerning them than we have now4 ,prompt information respecting such new developments is1 however1 more desirable than delay with a view to saying the last word on the subject1 which never can be said by any of us1 even if we should wait to the end of the lifetime4 ,for this reason it has appeared useful to collect and republish in convenient form the articles of this character which have appeared during the last few years4 ,w4 ,r4 ,,ingalls4 ,,august #a1 #aijf4 ,,contents ,,part ,i ,,notes ,,on ,,lead ,,mining ,,page ,,sources ,,of ,,lead ,,production ,,in ,,the ,,united ,,states 7,,walter ,,renton ,,ingalls7 #c ,,notes ,,on ,,the ,,source ,,of ,,the ,,southeast ,,missouri ,,lead 7,h4 ,a4 ,,wheeler7 #aj ,,mining ,,in ,,southeastern ,,missouri 7,,walter ,,renton ,,ingalls7 #af ,,lead ,,mining ,,in ,,southeastern ,,missouri 7,r4 ,d4 ,o4 ,,johnson7 #ah ,,the ,,lead ,,ores ,,of ,,southwestern ,,missouri 7,c4 ,v4 ,,petraeus ,,and ,w4 ,,geo4 ,,waring7 #bd ,,part ,,ii ,,roast-,,reaction ,,smelting ,,scotch ,,hearths ,,and ,,reverberatory ,,furnaces ,,lead ,,smelting ,,in ,,the ,,scotch ,,hearth 7,,kenneth ,w4 ,m4 ,,middleton7 #ca ,,the ,,federal ,,smelting ,,works1 ,,near ,,alton1 ,,ill4 7,o4 ,,pufahl7 #ch ,,lead ,,smelting ,,at ,,tarnowitz 7,,editorial7 #da ,,lead ,,smelting ,,in ,,reverberatory ,,furnaces ,,at ,,desloge1 ,,mo4 7,,walter ,,renton ,,ingalls7 #db ,,part ,,iii ,,sintering ,,and ,,briquetting ,,the ,,desulphurization ,,of ,,slimes ,,by ,,heap ,,roasting ,,at ,,broken ,,hill 7,e4 ,j4 ,,horwood7 #ea ,,the ,,preparation ,,of ,,fine ,,material ,,for ,,smelting 7,t4 ,j4 ,,greenway7 #ei ,,the ,,briquetting ,,of ,,minerals 7,,robert ,,schorr7 #fc ,a ,,bricking ,,plant ,,for ,,flue ,,dust ,,and ,,fine ,,ores 7,,jas4 ,c4 ,,bennett7 #ff ,,part ,,iv ,,smelting ,,in ,,the ,,blast ,,furnace ,,modern ,,silver-,,lead ,,smelting 7,,arthur ,s4 ,,dwight7 #gc ,,mechanical ,,feeding ,,of ,,silver-,,lead ,,blast ,,furnaces 7,,arthur ,s4 ,,dwight7 #ha ,,cost ,,of ,,smelting ,,and ,,refining 7,,malvern ,w4 ,,iles7 #if ,,smelting ,,zinc ,,retort ,,residues 7,e4 ,m4 ,,johnson7 #ajd ,,zinc ,,oxide ,,in ,,slags 7,w4 ,,maynard ,,hutchings7 #ajh ,,part ,v ,,lime-,,roasting ,,of ,,galena ,,the ,,huntington-,,heberlein ,,process #aac ,,lime-,,roasting ,,of ,,galena 7,,editorial7 #aad ,,the ,,new ,,methods ,,of ,,desulphurizing ,,galena 7,w4 ,,borchers7 #aaf ,,lime-,,roasting ,,of ,,galena 7,w4 ,,maynard ,,hutchings7 #abf ,,theoretical ,,aspects ,,of ,,lead-,,ore ,,roasting 7,c4 ,,guillemain7 #acc ,,metallurgical ,,behavior ,,of ,,lead ,,sulphide ,,and ,,calcium ,,sulphate 7,f4 ,o4 ,,doeltz7 #aci ,,the ,,huntington-,,heberlein ,,process 7,,donald ,,clark7 #add ,,the ,,huntington-,,heberlein ,,process ,,at ,,friedrichsh,,tte 7,a4 ,,biernbaum7 #adh ,,the ,,huntington-,,heberlein ,,process ,,from ,,the ,,hygienic ,,standpoint 7,a4 ,,biernbaum7 #afj ,,the ,,huntington-,,heberlein ,,process 7,,thomas ,,huntington ,,and ,,ferdinand ,,heberlein7 #afg ,,making ,,sulphuric ,,acid ,,at ,,broken ,,hill 7,,editorial7 #agd ,,the ,,carmichael-,,bradford ,,process 7,,donald ,,clark7 #age ,,the ,,carmichael-,,bradford ,,process 7,,walter ,,renton ,,ingalls7 #agg ,,the ,,savelsberg ,,process 7,,walter ,,renton ,,ingalls7 #ahf ,,lime-,,roasting ,,of ,,galena 7,,walter ,,renton ,,ingalls7 #aic ,,part ,,vi ,,other ,,methods ,,of ,,smelting ,,the ,,bormettes ,,method ,,of ,,lead ,,and ,,copper ,,smelting 7,,alfredo ,,lotti7 #bae ,,the ,,germot ,,process 7,,walter ,,renton ,,ingalls7 #bbd ,,part ,,vii ,,dust ,,and ,,fume ,,recovery ,,flues1 ,,chambers ,,and ,,bag-,,houses ,,dust ,,chamber ,,design 7,,max ,j4 ,,welch7 #bbi ,,concrete ,,in ,,metallurgical ,,construction 7,,henry ,w4 ,,edwards7 #bcd ,,concrete ,,flues 7,,edwin ,h4 ,,messiter7 #bdj ,,concrete ,,flues 7,,francis ,t4 ,,havard7 #bdb ,,bag-,,houses ,,for ,,saving ,,fume 7,,walter ,,renton ,,ingalls7 #bdd ,,part ,,viii ,,blowers ,,and ,,blowing ,,engines ,,rotary ,,blowers ,,vs4 ,,blowing ,,engines ,,for ,,lead ,,smelting 7,,editorial7 #bea ,,rotary ,,blowers ,,vs4 ,,blowing ,,engines 7,j4 ,,parke ,,channing7 #bed ,,blowers ,,and ,,blowing ,,engines ,,for ,,lead ,,and ,,copper ,,smelting 7,,hiram ,w4 ,,hixon7 #bef ,,blowing ,,engines ,,and ,,rotary ,,blowers 7,s4 ,e4 ,,bretherton7 #beh ,,part ,,ix ,,lead ,,refining ,,the ,,refining ,,of ,,lead ,,bullion 7,f4 ,l4 ,,piddington7 #bfc ,,the ,,electrolytic ,,refining ,,of ,,base ,,lead ,,bullion 7,,titus ,,ulke7 #bgj ,,electrolytic ,,lead ,,refining 7,,anson ,g4 ,,betts7 #bgd ,,part ,x ,,smelting ,,works ,,and ,,refineries ,,the ,,new ,,smelter ,,at ,,el ,,paso1 ,,texas 7,,editorial7 #bhe ,,new ,,plant ,,of ,,the ,,american ,,smelting ,,and ,,refining ,,company ,,at ,,murray1 ,,utah 7,,walter ,,renton ,,ingalls7 #bhg ,,the ,,murray ,,smelter1 ,,utah 7,o4 ,,pufahl7 #bia ,,the ,,pueblo ,,lead ,,smelters 7,o4 ,,pufahl7 #bid ,,the ,,perth ,,amboy ,,plant ,,of ,,the ,,american ,,smelting ,,and ,,refining ,,company 7,o4 ,,pufahl7 #bif ,,the ,,national ,,plant ,,of ,,the ,,american ,,smelting ,,and ,,refining ,,company 7,o4 ,,pufahl7 #bii ,,the ,,east ,,helena ,,plant ,,of ,,the ,,american ,,smelting ,,and ,,refining ,,company 7,o4 ,,pufahl7 #cjb ,,the ,,globe ,,plant ,,of ,,the ,,american ,,smelting ,,and ,,refining ,,company 7,o4 ,,pufahl7 #cjd ,,lead ,,smelting ,,in ,,spain 7,,hjalmar ,,eriksson7 #cjf ,,lead ,,smelting ,,at ,,monteponi1 ,,sardinia 7,,erminio ,,ferraris7 #caa ,,part ,i ,,notes ,,on ,,lead ,,mining ,,sources ,,of ,,lead ,,production ,,in ,,the ,,united ,,states ,,by ,,walter ,,renton ,,ingalls 7,november #bh1 #aijc7 ,statistics of lead production are of value in two directions3 7#a7 in showing the relative proportion of the kinds of lead produced2 and 7#b7 in showing the sources from which produced4 ,lead is marketed in three principal forms3 7a7 desilverized2 7b7 soft2 7c7 antimonial1 or hard4 ,the terms to distinguish between classes 8a0 and 8b0 are inexact1 because1 of course1 desilverized lead is soft lead4 ,desilverized lead itself is classified as 8corroding10 which is the highest grade1 and ordinary 8desilverized40 ,soft lead1 referring to the ,missouri product1 may be either 8ordinary0 or 8chemical hard40 ,the latter is such lead as contains a small percentage of copper and antimony as impurities1 which1 without making it really hard1 increase its resistance against the action of acids1 and therefore render it especially suitable for the production of sheet to be used in sulphuric-acid chamber construction and like purposes4 ,the production of chemical hard lead is a fortuitous matter1 depending on the presence of the valuable impurities in the virgin ores4 ,if present1 these impurities go into the lead1 and cannot be completely removed by the simple process of refining which is practised4 ,nobody knows just what proportions of copper and antimony are required to impart the desired property1 and consequently no specifications are made4 ,some chemical engineers call for a particular brand1 but this is really only a whim1 since the same brand will not be uniformly the same2 practically one brand is as good as another4 ,corroding lead is the very pure metal1 which is suitable for white lead manufacture4 ,it may be made either from desilverized or from the ordinary ,missouri product2 or the latter1 if especially pure1 may be classed as corroding without further refining4 ,antimonial lead is really an alloy of lead with about #ae to #cj per cent4 antimony1 which is produced as a by-product by the desilverizers of base bullion4 ,the antimony content is variable1 it being possible for the smelter to run the percentage up to #fj4 ,formerly it was the general custom to make antimonial lead with a content of #aj to #ab per cent4 ,sb2 later1 with #ah to #bj per cent42 while now #be to #cj per cent4 ,sb is best suited to the market4 ,the relative values of the various grades of lead fluctuate considerably1 according to the market place1 and the demand and supply4 ,the schedules of the ,american ,smelting and ,refining ,company make a regular differential of #aj;c4 per #ajj lb4 between corroding lead and desilverized lead in all markets4 ,in the ,st4 ,louis market1 desilverized lead used to command a premium of #e;c4 to #aj;c4 per #ajj lb4 over ordinary ,missouri2 but now they sell on approximately equal terms4 ,chemical hard lead sells sometimes at a higher price1 sometimes at a lower price1 than ordinary ,missouri lead1 according to the demand and supply4 ,there is no regular differential4 ,this is also the case with antimonial lead4#a ,the total production of lead from ores mined in the ,united ,states in #aija was #bgi1ibb short tons1 of which #baa1cfh tons were desilverized1 #eg1hih soft 7meaning lead from ,missouri and adjacent ,states7 and #aj1fef antimonial4 ,these are the statistics of 8,the ,mineral ,industry40 ,the ,united ,states ,geological ,survey reported substantially the same quantities4 ,in #aijb the production was #aii1fae tons of desilverized1 #gj1dbd tons of soft1 and #aj1dhe tons of antimonial1 a total of #bhj1ebd tons4 ,there is an annual production of #djjj to #ejjj tons of white lead direct from ore at ,joplin1 ,mo41 which increases the total lead production of the ,united ,states by1 say1 #cejj tons per annum4 ,the production of lead reported as 8soft0 does not represent the full output of ,missouri and adjacent ,states1 because a good deal of their ore1 itself non-argentiferous1 except to the extent of about #a oz4 per ton in certain districts1 is smelted with silver-bearing ores1 going thus into an argentiferous lead2 while in one case1 at least1 the almost non-argentiferous lead1 obtained by smelting the ore unmixed1 is desilverized for the sake of the extra refining4 ,lead-bearing ores are of widespread occurrence in the ,united ,states4 ,throughout the ,rocky ,mountains there are numerous districts in which the ore carries more or less lead in connection with gold and silver4 ,for this reason1 the lead mining industry is not commonly thought of as having such a concentrated character as copper mining and zinc mining4 ,it is the fact1 however1 that upward of #gj per cent4 of the lead produced in the ,united ,states is derived from five districts1 and in the three leading districts from a comparatively small number of mines4 ,the statistics of these for #aija to #aijd are as follows3#b ,,production1 ,,tons ,,per ,,cent4 ,,district #aija #aijb #aijc #aijd #aija #aijb #aijc #aijd,,ref4 ,cur d',alene #fh1iec #gd1gci #hi1hhj #ih1bdj #bd4c #bf4c #cb4e #cb4e;a ,southeast ,mo4 #df1feg #ef1eej #ei1ffj #ei1ajd #af4d #ai4i #ba4b #ai4f;b ,leadville1 ,colo4 #bh1ahj #ai1gbe #ah1agg #bc1eij #aj4j #f4i #f4f #g4h;c ,park ,city1 ,utah #bh1caj #cf1cjj #cf1ecd #cj1aib #aj4j #ab4h #ac4b #aj4j;d ,joplin1 ,mo4-,kan4 #bd1ejj #bb1acj #bj1jjj #bc1fjj #h4f #g4h #g4b #g4h;e ,total #aif1fjjbji1dddbbd1beabcd1gbf #fi4c #gc4g #ha4j #gg4g a4 ,the production in #aija and #aijb is computed from direct returns from the mines1 with an allowance of #f per cent4 for loss of lead in smelting4 ,the production in #aijc and #aijd is estimated at #ie per cent4 of the total lead product of ,idaho4 b4 ,this figure includes only the output of the mines at ,bonne ,terre1 ,flat ,river1 ,doe ,run1 ,mine la ,motte and ,fredericktown4 ,it is computed from the report of the ,state ,lead and ,zinc ,mine ,inspector as to ore produced1 the ore 7concentrates7 of the mines at ,bonne ,terre1 ,flat ,river and ,doe ,run being reckoned as yielding #fj per cent4 lead4 c4 ,report of ,state ,commissioner of ,mines4 d4 ,report of ,director of the ,mint on 8,production of ,gold and ,silver in the ,united ,states10 with allowance of #f per cent4 for loss of lead in smelting4 e4 ,from statistics reported by 8,the ,mineral ,industry10 reckoning the ore 7concentrates7 as yielding #gj per cent4 lead4 ,outside of these five districts1 the most of the lead produced in the ,united ,states is derived from other camps in ,idaho1 ,colorado1 ,missouri and ,utah1 the combined output of all other ,states being insignificant4 ,it is interesting to examine the conditions under which lead is produced in the five principal districts4 ,leadville1 ,colo4--,the mines of ,leadville1 which once were the largest lead producers of the ,united ,states1 became comparatively unimportant after the exhaustion of the deposits of carbonate ore1 but have attained a new importance since the successful introduction of means for separating the mixed sulphide ore1 which occurs there in very large bodies4 ,the lead production of ,leadville in #ahig was #aa1hej tons2 #ag1igc tons in #ahih2 #bd1bii tons in #ahii2 #ca1cjj tons in #aijj2 #bh1ahj tons in #aija1 and #ai1gbe tons in #aijb4 ,the ,leadville mixed sulphide ore assays about #h per cent4 ,pb1 #be per cent4 ,zn and #aj oz4 silver per ton4 ,it is separated into a zinc product assaying about #ch per cent4 ,zn and #f per cent4 ,pb1 and a galena product assaying about #de per cent4 ,pb1 #aj or #ab per cent4 ,zn1 and #aj oz4 silver per ton4 ,cur d',alene4--,the mines of this district are opened on fissure veins of great extent4 ,the ore is of low grade and requires concentration4 ,as mined1 it contains about #aj per cent4 lead and a variable proportion of silver4 ,it is marketed as mineral1 averaging about #ej per cent4 ,pb and #cj oz4 silver per ton4 ,the production of lead ore in this district is carried on under the disadvantages of remoteness from the principal markets for pig lead1 high-priced labor1 and comparatively expensive supplies4 ,it enjoys the advantages of large orebodies of comparatively high grade in lead1 and an important silver content1 and in many cases cheap water power1 and the ability to work the mines through adit levels4 ,the cost of mining and milling a ton of crude ore is #b4ej to #c4ej4 ,the mills are situated1 generally1 at some distance from the mines1 the ore being transported by railway at a cost of #h to #bj;c4 per ton4 ,the dressing is done in large mills at a cost of #dj to #ej;c4 per ton4 ,about #ge per cent4 of the lead of the ore is recovered4 ,the concentrates are sold at #ij per cent4 of their lead contents and #ie per cent4 of their silver contents1 less a smelting charge of #h per ton1 and a freight rate of #h per ton on ore of less than #ej value per ton1 #aj on ore worth #ej to #fe1 and #ab on ore worth more than #fe2 the ore values being computed f4 o4 b4 mines4 ,the settling price of lead is the arbitrary one made by the ,american ,smelting and ,refining ,company4 ,with lead 7in ore7 at #c4e;c4 and silver at #ej;c41 the value1 f4 o4 b4 mines1 of a ton of ore containing #ej per cent4 ,pb and #cj oz4 silver is approximately as follows3 #ajjj #j4ij #ijj lb4 lead1 at #c4e;c4 #ca4ej #cj #j4ie #bh4e oz4 silver1 at #ej;c4 #ad4be ------------ ,gross value1 f4 o4 b4 mines #de4ge ,less freight1 #aj1 and smelting charge1 #h #ah4jj ------------ ,net value1 f4 o4 b4 mines #bg4ge ,assuming an average of #f tons of crude ore to #a ton of concentrate1 the value per ton of crude ore would be about #d4fb1 and the net profit per ton about #a4fb1 which figures are increased #bc4ge;c4 for each #e;c4 rise in the value of silver above #ej;c4 per ounce4 ,the production of the ,cur d',alene since #ahie1 as reported by the mines1 has been as follows3 ---------------------------------------- ------------------------------- ,,year ,,lead1 ,,tons ,,silver1 ,,oz4 ,,ratio#c ---------------------------------------- ------------------------------- #ahif #cg1bej #b1ejj1jjj #fg4a #ahig #eg1ggg #c1egi1dbd #fa4i #ahih #ef1cci #c1cii1ebd #fj4c #ahii #ej1jjf #b1gcf1hgb #ed4g #aijj #ha1ece #d1gee1hgg #eh4c #aija #fh1iec #c1cdi1ecc #dh4e #aijb #gd1gci #d1dhi1edi #fj4j #aijc #dajj1cee #e1gea1fac #eg4c #aijd #dajh1ied #f1bdg1gie #eg4d ---------------------------------------- ------------------------------- ,the number of producers in the ,cur d',alene district is comparatively small1 and many of them have recently consolidated1 under the name of the ,federal ,mining and ,smelting ,company4 ,outside of that concern are the ,bunker ,hill ,sullivan1 the ,morning and the ,hercules mines1 control of which has lately been secured by the ,american ,smelting and ,refining ,company4 ,southeastern ,missouri4--,the most of the lead produced in this region comes from what is called the disseminated district1 comprising the mines of ,bonne ,terre1 ,flat ,river1 ,doe ,run1 ,mine la ,motte and ,fredericktown1 of which those of ,bonne ,terre and ,flat ,river are the most important4 ,the ore of this region is a magnesian limestone impregnated with galena4 ,the deposits lie nearly flat and are very large4 ,they yield about #e per cent4 of mineral1 which assays about #fe per cent4 lead4 ,the low grade of the ore is the only disadvantage which this district has1 but this is so much more than offset by the numerous advantages1 that mining is conducted very profitably1 and it is an open question whether lead can be produced more cheaply here or in the ,cur d',alene4 ,the mines of southeastern ,missouri are only #fj to #ajj miles distant from ,st4 ,louis1 and are in close proximity to the coalfields of southern ,illinois1 which afford cheap fuel4 ,the ore lies at depths of only #ajj to #ejj ft4 below the surface4 ,the ground stands admirably1 without any timbering4 ,labor and supplies are comparatively cheap4 ,mining and milling can be done for #a4je to #a4be per ton of crude ore1 when conducted on the large scale that is common in this district4 ,most of the mining companies are equipped to smelt their own ore1 the smelters being either at the mines or near ,st4 ,louis4 ,the freight rate on concentrates to ,st4 ,louis is #a4dj per ton2 on pig lead it is #b4aj per ton4 ,the total cost of producing pig lead1 delivered at ,st4 ,louis1 is about #b4be;c4 per pound1 not allowing for interest on the investment1 amortization1 etc4 ,the production of the mines in the disseminated district in #aija was equivalent to #df1feg tons of pig lead2 in #aijb it was #ef1eej tons4 ,the milling capacity of the district is about #fjjj tons per day1 which corresponds to a capacity for the production of about #eg1jjj tons of pig lead per annum4 ,the ,st4 ,joseph ,lead ,company is building a new #ajjj ton mill1 and the ,st4 ,louis ,smelting and ,refining ,company 7,national ,lead ,company7 is further increasing its output1 which improvements will increase the daily milling capacity by about #adjj tons1 and will enable the district to put out upward of #ff1jjj tons of pig lead4 ,in this district1 as in the ,cur d',alene1 the industry is closely concentrated1 there being only nine producers1 all told4 ,park ,city1 ,utah4--,nearly all the lead produced by this camp comes from the ,silver ,king1 ,daly ,west1 ,ontario1 ,quincy1 ,anchor and ,daly mines1 which have large veins of low-grade ore carrying argentiferous galena and blende1 a galena product being obtained by dressing1 and zinkiferous tailings1 which are accumulated for further treatment as zinc ore1 when market conditions justify4#e ,joplin ,district4--,the lead production of southwestern ,missouri and southeastern ,kansas1 in what is known as the ,joplin district1 is derived entirely as a by-product in dressing the zinc ore of that district4 ,it is obtained as a product assaying about #gg per cent4 ,pb1 and is the highest grade of lead ore produced1 in large quantity1 anywhere in the ,united ,states4 ,it is smelted partly for the production of pig lead1 and partly for the direct manufacture of white lead4 ,the lead ore production of the district was #ca1bid tons in #ahie1 #bf1ibg tons in #ahif1 #bi1egh tons in #ahig1 #bf1deg tons in #ahih1 #bd1ajj tons in #ahii1 #bh1ejj tons in #aijj1 #ce1jjj tons in #aija1 and #ca1fae tons in #aijb4 ,the production of lead ore in this district varies more or less1 according to the production of zinc ore1 and is not likely to increase materially over the figure attained in #aija4 ,,notes ,,on ,,the ,,source ,,of ,,the ,,southeast ,,missouri ,,lead ,,by ,h4 ,a4 ,,wheeler 7,march #ca1 #aijd7 ,the source of the lead that is being mined in large quantities in southeastern ,missouri has been a mooted question4 ,nor is the origin of the lead a purely theoretical question1 as it has an important bearing on the possible extension of the orebodies into the underlying sandstone4 ,the disseminated lead ores of ,missouri occur in a shaly1 magnesian limestone of ,cambrian age in ,st4 ,franois1 ,madison and ,washington counties1 from #fj to #acj miles south of ,st4 ,louis4 ,the limestone is known as the ,bonne ,terre1 or lower half of 8the third magnesian limestone0 of the ,missouri ,geological ,survey1 and rests on a sandstone1 known as 8the third sandstone10 that is the base of the sedimentary formations in the area4 ,under this sandstone occur the crystalline porphyries and granites of ,algonkian and ,archean age1 which outcrop as knobs and islands of limited extent amid the unaltered ,cambrian and ,lower ,silurian sediments4 ,the lead occurs as irregular granules of galena scattered through the limestone in essentially horizontal bodies that vary from #e to #ajj ft4 in thickness1 from #be to #ejj ft4 in width1 and have exceeded #ijjj ft4 in length4 ,there is no vein structure1 no crushing or brecciation of the inclosing rock1 yet these orebodies have well defined axes or courses1 and remarkable reliability and persistency4 ,it is true that the limestone is usually darker1 more porous1 and more apt to have thin seams of very dark 7organic7 shales where it is ore-bearing than in the surrounding barren ground4 ,the orebodies1 however1 fade out gradually1 with no sharp line between the pay-rock and the non-paying1 and the lead is rarely1 if ever1 entirely absent in any extent of the limestone of the region4 ,while the main course of the orebodies seems to be intimately connected with the axes of the gentle anticlinal folds1 numerous cross-runs of ore that are associated with slight faults are almost as important as the main shoots1 and have been followed for #ejjj ft4 in length4 ,these cross-runs are sometimes richer than the main runs1 at least near the intersections1 but they are narrower1 and partake more of the type of vertical shoots1 as distinguished from the horizontal sheet-form4 ,most of the orebodies occur at1 or close to1 the base of the limestone1 and frequently in the transition rock between the underlying sandstone and the limestone1 though some notable and important bodies have been found from #ajj to #bjj ft4 above the sandstone4 ,this makes the working depth from the surface vary from #aej to #bej ft41 for the upper orebodies1 to #cjj to #ejj ft4 deep to the main or basal orebodies1 according as erosion has removed the ore-bearing limestone4 ,the thickness of the latter ranges from #djj to #ejj ft4 ,associated with the galena are less amounts of pyrite1 which especially fringes the orebodies1 and very small quantities of chalcopyrite1 zinc blende1 and siegenite 7the double sulphide of nickel and cobalt74 ,calcite also occurs1 especially where recent leaching has opened vugs1 caves1 or channels in the limestone1 when secondary enrichment frequently incrusts these openings with crystals of calcite and galena4 ,no barite ever occurs with the disseminated ore1 though it is the principal gangue mineral in the upper or ,potosi member of the third magnesian limestone1 and is never absent in the small ore occurrences in the still higher second magnesian limestone4 ,while the average tenor of the ore is low1 the yield being from #c to #d per cent4 in pig lead1 they are so persistent and easy to mine that the district today is producing about #gj1jjj tons of pig lead annually1 and at a very satisfactory profit4 ,as the output was about #bejj tons lead in #ahgc1 approximately #hejj tons in #ahhc1 and about #bj1jjj tons in #ahic1 it shows that this district is young1 for the principal growth has been within the last five years4 ,of the numerous but much smaller occurrences of lead elsewhere in ,missouri and the ,mississippi valley1 none resembles this district in character1 a fact which is unique4 ,for while the ,mechernich lead deposits1 in ,germany1 are disseminated1 and of even lower grade than in ,missouri1 they occur in a sandstone1 and 7like all the lead deposits outside of the ,mississippi valley7 they are argentiferous1 at least to an extent sufficient to make the extraction of the silver profitable2 and on the non-argentiferous character of the disseminated deposits hangs my story4 ,of the numerous hypotheses advanced to account for the origin of these deposits1 there are only two that seem worthy of consideration3 7a7 the lateral secretion theory1 and 7b7 deposition from solutions of deep-seated origin4 ,other theories evolved in the pioneer period of economic geology are interesting1 chiefly by reason of the difficulties under which the early strugglers after geological knowledge blazed the pathway for modern research and observation4 ,the lateral secretion theory1 as now modernized into the secondary enrichment hypothesis1 has much merit when applied to the southeastern and central ,missouri lead deposits4 ,for the limestones throughout ,missouri--and they are the outcropping formation over more than half of the ,state--are rarely1 if ever1 devoid of at least slight amounts of lead and zinc1 although they range in age from the ,carboniferous down to the ,cambrian4 ,the sub-,carboniferous formation is almost entirely made up of limestones1 which aggregate #abjj to #aejj ft4 in thickness4 ,they frequently contain enough lead 7and less often zinc7 to arouse the hopes of the farmer1 and more or less prospecting has been carried on from ,hannibal to ,st4 ,louis1 or #abe miles along the ,mississippi front1 and west to the central part of the ,state1 but with most discouraging results4 ,in the rock quarries of ,st4 ,louis1 immediately under the lower coal measures1 fine specimens of millerite of world-wide reputation occur as filiform linings of vugs in this sub-,carboniferous limestone4 ,these vugs occur in a solid1 unaltered rock which gives no clue to the existence of the vug or cavity until it is accidentally broken4 ,the vugs are lined with crystals of pink dolomite1 calcite and millerite1 with occasionally barite1 selenite1 galena and blende4 ,they occur in a well-defined horizon about #e ft4 thick1 and the vugs in the limestone above and below this millerite bed contain only calcite1 or less frequently dolomite4 ,yet this sub-,carboniferous formation in southwestern ,missouri1 about ,joplin1 carries the innumerable pockets and sheets of lead and zinc that have made that district the most important zinc producer in the world4 ,while faulting and limited folding occur in eastern and central ,missouri to fully as great an extent as in ,st4 ,franois county or the ,joplin district1 thus far no mineral concentration into workable orebodies has been found in this formation1 except in the ,joplin area4 ,the next important series of limestones that make up most of the central portion of ,missouri are of ,silurian age1 and in them lead and zinc are liberally scattered over large areas4 ,in the residual surface clays left by dissolution of the limestone1 the farmers frequently make low wages by gophering after the liberated lead1 and the aggregate of these numerous though insignificant gopher-holes makes quite a respectable total4 ,but they are only worked when there is nothing else to do on the farm1 as with rare exceptions they do not yield living wages1 and the financial results of mining the rock are even less satisfactory4 ,yet a few small orebodies have been found that were undoubtedly formed by local leaching and re-precipitation of this diffused lead and zinc4 ,such orebodies occur in openings or caves1 with well crystallized forms of galena and blende1 and invariably associated with crystallized 8tiff0 or barite4 ,i am not aware of any of these pockets or secondary enrichments having produced as much as #bjjj tons of lead or zinc1 and very few have produced as much as #ejj tons1 although one of these pockets was recently exploited with heroic quantities of printer's ink as the largest lead mine in the world4 ,yet there are large areas in which it is almost impossible to put down a drill-hole without finding 8shines0 or trifling amounts of lead or zinc4 ,that these central ,missouri lead deposits are due to lateral secretion there seems little doubt1 and it is possible that larger pockets may yet be found where more favorable conditions occur4 ,when the lateral secretion theory is applied to the disseminated deposits of southeastern ,missouri1 we are confronted by enormous bodies of ore1 absence of barite1 non-crystallized condition of the galena except in local1 small1 evidently secondary deposits1 and well-defined courses for the main and cross-runs of ore4 ,the ,bonne ,terre orebody1 which has been worked longest and most energetically1 has attained a length of nearly #ijjj ft41 with a production of about #cej1jjj tons or #cj1jjj1jjj of lead1 and is far from being exhausted4 ,orebodies recently opened are quite as promising4 ,the country rock is not as broken nor as open as in central ,missouri1 and is therefore much less favorable for the lateral circulation of mineral waters1 yet the orebodies vastly exceed those of the central region4 ,further1 the ,bonne ,terre formation is heavily intercalated with thick sheets of shale that would hinder overlying waters from reaching the base of the ore-horizon1 where most of the ore occurs1 so that the leachable area would be confined to a very limited vertical range1 or to but little greater thickness than the #ajj ft4 or so in which most of the orebodies occur4 ,while ,i have always felt that such large bodies1 showing relatively rapid precipitation of the lead1 could not be satisfactorily explained except as having a deep-seated origin1 the fact that the disseminated ore is practically non-argentiferous1 or at least carries only one to three ounces per ton1 has been a formidable obstacle4 ,for the lead in the small fissure-veins that occasionally occur in the adjacent granite has always been reported as argentiferous4 ,thus the ,einstein silver mine1 near ,fredericktown1 worked a fissure-vein from #a to #f ft4 wide in the granite4 ,it had a typical complex vein-filling and structure1 and carried galena that assayed from #dj to #bjj oz4 per ton4 ,while the quantity of ore obtained did not justify the expensive plant erected to operate it1 the galena was rich in silver1 whereas in the disseminated ores at the ,mine la ,motte mine1 ten miles distant1 only the customary #a4e oz4 per ton occurs4 ,occasionally fine-grained specimens of galena that ,i have found in the disseminated belt would unquestionably be rated as argentiferous by a ,western miner1 but the assay showed that the structure in this case was due to other causes1 as only about two ounces were found4 ,an apparent exception was reported at the ,peach ,orchard diggings1 in ,washington county1 in the higher or ,potosi member of the third magnesian limestone1 where ,arthur ,thacher found sulphide and carbonate ore carrying #h to #aj oz4 of silver per ton2 and a short-lived hamlet1 known as ,silver ,city1 sprang up to work them4 ,i found1 however1 that these deposits are associated with little vertical fissure-veins or seams that unquestionably come up from the underlying porphyry4 ,recently ,i examined the ,jackson ,revel mine1 which has been considered a silver mine for the last fifty years4 ,it lies about seven miles south of ,fredericktown1 and is a fissure-vein in ,algonkian felsite1 where it protrudes1 as a low hill1 through the disseminated limestone formation4 ,a shaft has just been sunk about #aej ft4 at less than #ajjj ft4 from the feather edge of the limestone4 ,the vein is narrow1 only one to twelve inches wide1 with slicken-sided walls1 runs about ,n4 #bj deg4 ,e41 and dips #hj to #hf deg4 eastward4 ,white quartz forms the principal part of the filling2 the vein contains more or less galena and zinc blende4 ,assays of the clean galena made by ,prof4 ,w4 ,b4 ,potter show only #b4e oz4 silver per ton1 or no more than is frequently found in the disseminated lead ores4 ,as the lead in this fissure vein may be regarded as of undoubted deep origin1 and it is practically non-argentiferous1 this would seem to remove the last objection to the theory of the deep-seated source of the lead in the disseminated deposits of southeast ,missouri4 ,,mining ,,in ,,southeastern ,,missouri ,,by ,,walter ,,renton ,,ingalls 7,february #ah1 #aijd7 ,the ,st4 ,joseph ,lead ,company1 in the operation of its mines at ,bonne ,terre1 does not permit the cages employed for hoisting purposes to be used for access to the mine4 ,men going to and from their work must climb the ladders4 ,this rule does not obtain in the other mines of the district4 ,the ,st4 ,joseph ,lead ,company employs electric haulage for the transport of ore underground at ,bonne ,terre4 ,in the other mines of the district1 mules are generally used4 ,the flow of water in the mines of the district is extremely variable2 some have very little2 others have a good deal4 ,the ,central mine is one of the wettest in the entire district1 making about #bjjj gal4 of water per minute4 ,coal in southeastern ,missouri costs #b to #b4be per ton delivered at the mines1 and the cost of raising #bjjj gal4 of water per minute from a depth of something like #cej ft4 is a very considerable item in the cost of mining and milling1 which1 in the aggregate1 is expected to come to not much over #a4be per ton4 ,the ore shoots in the district are unusually large4 ,their precise trend has not been identified4 ,some consider the predominance of trend to be northeast2 others1 northwest4 ,they go both ways1 and appear to make the greatest depositions of ore at their intersections4 ,however1 the network of shoots1 if that be the actual occurrence1 is laid out on a very grand scale4 ,vertically there is also a difference4 ,some shafts penetrate only one stratum of ore2 others1 two or three4 ,the orebody may be only a few feet in thickness2 it may be #ajj ft4 or more4 ,the occurrence of several overlying orebodies obviously indicates the mineralization of different strata of limestone1 while in the very thick orebodies the whole zone has apparently been mineralized4 ,the grade of the ore is extremely variable4 ,it may be only #a or #b per cent4 mineral1 or it may be #ae per cent4 or more4 ,however1 the average yield for the district1 in large mines which mill #ejj to #abjj tons of ore per day1 is probably about #e per cent4 of mineral1 assaying #fe per cent4 ,pb1 which would correspond to a yield of #c4be per cent4 metallic lead in the form of concentrate4 ,the actual recovery in the dressing works is probably about #ge per cent41 which would indicate a tenure of about #d4cc per cent4 lead in the crude ore4 ,,lead ,,mining ,,in ,,southeastern ,,missouri ,,by ,r4 ,d4 ,o4 ,,johnson 7,september #af1 #aije7 ,the lead deposits of southeastern ,missouri carry galena disseminated in certain strata of magnesian limestone4 ,their greater dimensions are generally horizontal1 but with outlines extremely irregular4 ,the large orebodies consist usually of a series of smaller bodies disposed parallel to one another4 ,these smaller members may coalesce1 but are generally separated from one another by a varying thickness of lean ore or barren rock4 ,the vertical and lateral dimensions of an orebody may be determined with a fair degree of accuracy by diamond drilling1 and a map may be constructed from the information so obtained4 ,such a map 7on which are plotted the surface contours7 makes it possible to determine closely the proper location of the shaft1 or shafts1 considering also the surface and underground drainage and tramming4 ,the first shafts in the district were sunk at ,bonne ,terre1 where the deposits lie comparatively near the surface4 ,the early practice at this point was to sink a number of small one-compartment shafts4 ,as the deposits were followed deeper1 this gave way to the practice of putting down two-compartment shafts equipped much more completely than were the shallower shafts4 ,at ,flat ,river 7where the deposits lie at much greater depths1 some being over #ejj ft47 the shafts are #g #ad ft41 #f #ah ft41 and #g #bj ft4 ,these larger dimensions give room not only for two cage-ways and a ladder-way1 but also for a roomy pipe-compartment4 ,the large quantities of water to be pumped in this part of the district make the care of the pipes in the shafts a matter of first importance4 ,at ,bonne ,terre only such a quantity of water was encountered as could be handled by bailing or be taken out with the rock2 there the only pipe necessary was a small air-pipe down one corner of the shaft4 ,when the quantity of water encountered is so great that the continued working of the mine depends upon its uninterrupted removal1 the care of the pipes becomes a matter of great importance4 ,a shaft which yields from #djjj to #ejjj gal4 of water per minute is equipped with two #ab in4 column pipes and two #d in4 steam pipes covered and sheathed4 ,moreover1 the pipe compartment will probably contain an #h in4 air-pipe1 besides speaking-tubes1 pipes for carrying electric wires1 and pipes for conducting water from upper levels to the sump4 ,to care for these properly there are required a separate compartment and plenty of room4 ,shafts are sunk by using temporary head frames and iron buckets of from #h to #ad cu4 ft4 capacity4 ,where the influx of water was small1 #ajd ft4 have been sunk in #cj days1 with three #h hour shifts1 two drills1 and two men to each drill2 #b in4 drills are used almost exclusively2 #c in4 drills have been used in sinking1 but without apparent increase in speed4 ,the influence of the quantity of water encountered upon the speed of sinking 7and the consequent cost per foot7 is so great that figures are of little value4 ,conditions are not at all uniform4 ,at some point 7usually before #bjj ft4 is reached7 a horizontal opening will be encountered4 ,this opening invariably yields water1 the amount following closely the surface precipitation4 ,it is the practice to establish at this point a pumping station4 ,the shaft is 8ringed0 and the water is directed into a sump on the side1 from which it is pumped out4 ,this sump receives also the discharge of the sinking pumps4 ,the shafts sunk in solid limestone require no timbering other than that necessary to support the guides1 pipes1 and ladder platforms4 ,these timbers are #h #h in4 and #f x #h in41 spaced #g or #h ft4 apart4 ,shafts are sunk to a depth of #aj ft4 below the point determined upon as the lower cage landing4 ,from the end at the bottom a narrow drift is driven horizontally to a distance of #ae ft42 at that point it is widened out to #aj ft4 and driven #bj ft4 further4 ,the whole area 7#aj #bj ft47 is then raised to a point #bh or #cj ft4 above the bottom of the drift from the shaft4 ,the lower part of this chamber constitutes the sump4 ,starting from this chamber 7on one side and at a point #aj ft4 above the cage landing1 or #bj ft4 above the bottom of the sump71 the 8pump-house0 is cut out4 ,this pump-house is cut #dj ft4 long and is as wide as the sump is long1 namely1 #bj ft4 ,a narrow drift is driven to connect the top of the pump-house with the shaft4 ,through this drift the various pipes enter the pump-house from the shaft4 ,the pumps are thus placed at an elevation of #aj ft4 above the bottom of the mine4 ,flooding of mines1 due to failure of pumps or to striking underground bodies of water1 taught the necessity of placing the pumps at such an elevation that they would be the last to be covered1 thus giving time for getting or keeping them in operation4 ,the pumps are placed on the solid rock1 the air pumps and condensers at a lower level on timbers over the sump4 ,with this arrangement1 the bottom of the shaft serves as an antechamber for the sump1 in which is collected the washing from the mine and the dripping from the shaft4 ,the sump proper rarely needs cleaning4 ,the pumps are generally of high-grade1 compound-and triple-expansion1 pot-valved1 outside-packed plunger pattern4 ,plants with electrical power distribution have recently installed direct-connected compound centrifugal pumps with entire success4 ,pumps of the ,cornish pattern have never been used much in this region4 ,one such pump has been installed1 but the example has not been followed even by the company putting it in4 ,the irregular disposition of the ore renders any systematic plan of drifting or mining 7as in coal or vein mining7 impossible4 ,on each side of the shaft and in a direction at right angles to its greater horizontal dimension1 drifts #ab to #ad ft4 in width are driven to a distance of #fj or #gj ft4 ,in these broad drifts are located the tracks and also the 8crossovers0 for running the cars on and off the cage4 ,when a deposit is first opened up1 it is usually worked on two1 and sometimes three1 levels4 ,these eventually cut into one another1 when the ore is hoisted from the lower level alone4 ,the determination of the depth of the lower level is a matter of compromise4 ,much good ore may be known to exist below2 when it comes to mining1 it will have to be taken out at greater expense2 but the level is aimed to cut through the lower portions of the main body4 ,it is generally safe to predict that the ore lying below the upper levels will eventually be mined from a lower level without the expense of local underground hoisting and pumping4 ,the ore has simply to be followed2 no one can say in advance how it is going to turn out4 ,the irregularity of the deposits renders any general plan of mining of little or no value4 ,some managers endeavor to outline the deposits by working on the outskirts1 leaving the interior as 8ore reserves40 ,such reserves have been found to be no reserves at all1 though the quality of the rock may be fairly well determined by underground diamond drilling4 ,many of the deposits are too narrow to permit the employment of any system of outlining and at the same time keeping up the ore supply4 ,the individual bodies constituting the general orebody are rarely1 if ever1 completely separated by barren rock2 some 8stringers0 or 8leaders0 of ore connect them4 ,the careful superintendent keeps a record on the monthly mine map of all such occurrences1 or otherwise1 or of blank walls of barren rock that mark the edge of the deposit4 ,this precaution finds abundant reward when the drills commence to 8cut poor10 and when a search for ore is necessary4 ,the method of mining is to rise to the top of the ore and to carry forward a #f ft4 breast4 ,if the ore is thick enough1 this is followed by the underhand stope4 ,drill holes in the breast are usually #g or #h ft4 in depth2 stope holes1 #aj to #ad feet4 ,both the roof and the floor are drilled with #h or #aj ft4 holes placed #h or #aj ft4 apart4 ,these serve to prospect the rock in the immediate neighborhood2 in the roof they serve the further very important purpose of draining out water that might otherwise accumulate between the strata and that might force them to fall4 ,the condition or safety of the roof is determined by striking with a hammer4 ,if the sound is hollow or 8drummy10 the roof is unsafe4 ,if water is allowed to accumulate between the loose strata1 obviously it is not possible to determine the condition of the roof4 ,it is the duty of two men on each shift to keep the mine in a safe condition by taking down all loose and dangerous masses of rock4 ,these men are known as 8miners40 ,it sometimes happens that a considerable area of the roof gets into such a dangerous condition that it is either too risky or too expensive to put in order1 in which case the space underneath is fenced off4 ,as a general thing1 the mines are safe and are kept so4 ,there are but few accidents of a serious nature due to falling rock4 ,the roof is supported entirely by pillars2 no timbering whatever is used4 ,the pillars are parts of the orebody or rock that is left4 ,they are of all varieties of size and shape4 ,they are usually circular in cross-section1 #aj to #ae ft4 in diameter and spaced #bj to #ce ft4 apart1 depending upon the character of the roof4 ,pillars generally flare at the top to give as much support to the roof as possible4 ,the hight of the pillars corresponds1 of course1 to the thickness of the orebody4 ,all drilling is done by #b in4 percussion drills4 ,in the early days1 when diamonds were worth #f per carat1 underground diamond drills were used4 ,diamond drills are used now occasionally for putting in long horizontal holes for shooting down 8drummy0 roof4 ,air pressure varies from #fj to #hj lb4 ,pressures of #ajj lb4 and more have been used1 but the repairs on the drills became so great that the advantages of the higher pressure were neutralized4 ,each drill is operated by two men1 designated as 8drillers10 or 8front hand0 and 8back hand40 ,the average amount of drilling per shift of #aj hours is in the neighborhood of #dj ft41 though at one mine an average of #ee ft4 was maintained4 ,in some of the mines the 8drillers0 and 8back hands0 do the loading and firing2 in others that is done by 8firers10 who do the blasting between shifts4 ,when the drillers do the firing1 there is employed a 8powder monkey10 who makes up the 8niphters10 or sticks of powder1 in which are inserted and fastened the caps and fuse2 #ce per cent4 powder is used for general mining4 ,battery firing is employed only in shaft sinking4 ,in the mining work this is found to be much more expensive2 the heavy concussions loosen the stratum of the roof and make it dangerous4 ,large quantities of oil are used for lubrication and illumination4 8,zero0 black oil and oils of that grade are used on the drills4 ,miners' oil is generally used for illumination1 though some of the mines use a low grade of felsite wax4 ,two oil cans 7each holding about #a pints7 are given to each pair of drillers1 one can for black oil and one for miners' oil4 ,these cans1 properly filled1 are given out to the men1 as they go on shift1 at the 8oil-house10 located near the shaft underground4 ,this 8oil-house0 is in charge of the 8oil boy10 whose duty it is to keep the cans clean1 to fill them and to give them out at the beginning of the shift4 ,the cans are returned to the oil-house at the end of the shift4 ,kerosene is used in the hat-lamps in wet places4 ,the 8oil-houses0 are provided with three tanks4 ,in some instances these tanks are charged through pipes coming down the shaft from the surface oil-house4 ,these tanks are provided with oil-pumps and graduated gage-glasses4 ,shovelers or loaders operate in gangs of #h to #ab1 and are supervised by a 8straw boss10 who is provided with a gallon can for illuminating oil4 ,the cars are #bj cu4 ft4 7#a ton7 capacity4 ,under ordinary conditions one shoveler will load #bj of these cars in a shift of #aj hours4 ,they use 8half-spring10 long-handled1 round-pointed shovels4 ,cars are of the solid-box pattern1 and are dumped in cradles4 ,loose and 8,anaconda0 manganese-steel wheels are the most common4 ,gage of track1 #bd to #cj in41 #af lb4 rails on main lines and #ab lb4 on the side and temporary tracks4 ,cars are drawn by mules4 ,one mine has installed compressed-air locomotives and is operating them with success4 ,shafts are generally equipped with geared hoists1 both steam and electrically driven4 ,later hoists are all of the first-motion pattern4 ,generally the cars are hoisted to the top and dumped with cradles4 ,one shaft1 however1 is provided with a #e-ton skip1 charged at the bottom from a bin1 into which the underground cars are dumped4 ,upon arriving at the top the skip dumps automatically4 ,this design exhibits a number of advantages over the older method and will probably find favor with other mine operators4 ,,the ,,lead ,,ores ,,of ,,southwestern ,,missouri ,,by ,c4 ,v4 ,,petraeus ,,and ,w4 ,,geo4 ,,waring 7,october #ba1 #aije7 ,the lead ore of southwestern ,missouri1 and the adjoining area in the vicinity of ,galena1 ,kan41 is obtained as a by-product of zinc mining1 the galena being separated from the blende in the jigging process4 ,formerly the galena 7together with 8dry-bone10 including cerussite and anglesite7 was the principal ore mined from surface deposits in clay1 the blende being the subsidiary product4 ,in the deeper workings blende was found largely to predominate2 this is shown by the shipments of the district in #aijd1 which amounted to #bfg1big tons of zinc concentrate and #cd1ecc tons of lead concentrate4 ,the lead occurs in segregated cubes1 from less than one millimeter up to one foot in diameter4 ,the cleavage is perfect1 so that each piece of ore when struck with a hammer breaks up into smaller perfect cubes4 ,in this respect the ore differs from the galena encountered in the ,rocky ,mountain regions1 where torsional or shearing strains seem in most instances to have destroyed the perfect cleavage of the minerals subsequent to their original deposition4 ,cases of schistose and twisted structure occur in lead deposits of the ,joplin district but rarely1 and they are always quite local4 ,the separation of the galena from the blende and marcasite 78mundic07 in the ordinary process of jigging is very complete2 the percentage of zinc and iron in the lead concentrate is insignificant4 ,as an illustration of this1 the assays of #ajj recent consecutive shipments of lead ore from the district1 taken at random1 are cited as follows3 #g shipments assayed from #eg to #gj lead #ae shipments assayed from #gj to #ge lead #df shipments assayed from #ge to #gi lead #cb shipments assayed from #hj to #hd4d lead ,average of #ajj shipments #gh4d lead ,fourteen shipment samples1 ranging from #gj to #hd4d per cent4 lead1 were tested for zinc and iron4 ,these averaged #b4bd per cent4 ,fe and #a4gh per cent4 ,zn1 the highest zinc content being #d4e per cent4 ,no bismuth or arsenic1 and only very minute traces of antimony1 have ever been found in these ores4 ,they contain only about #j4jjje per cent4 of silver 7one-seventh of an ounce per ton7 and scarcely more than that of copper 7occurring as chalcopyrite74 ,the pig lead produced from these ores is therefore very pure1 soft and uniform in quality1 so that the term 8soft ,missouri lead0 has become a synonym for excellence in the manufacture of lead alloys and products1 such as litharge1 red and white lead1 and orange mineral4 ,its freedom from bismuth1 which is generally present in ,colorado lead1 makes it particularly suitable for white lead2 also for glass-maker's litharge and red lead4 ,these oxides1 for use in making crystal glass1 must be made by double refining so as to remove even the small quantities of silver and copper that are present4 ,the resulting product1 made from soft ,missouri lead1 is far superior to any refined lead produced anywhere in this country or in ,europe1 even excelling the famous ,tarnowitz lead4 ,it gives a luster and clarity to the glass that no other lead will produce4 ,lead from southeastern ,missouri1 ,kentucky1 ,illinois1 ,iowa1 and ,wisconsin yields identical results1 but the refining is more difficult1 not only because the lead contains a little more silver and copper1 but also because it contains more antimony4 ,the valuation of the lead concentrate produced in the ,joplin district is based upon a wet assay1 usually the molybdate or ferrocyanide method4 ,the price paid is determined variously4 ,one buyer pays a fixed price for average ore1 making no deductions2 as1 for example1 at present rates1 #cb4be per #ajjj lb4 whether the ore assays #ge or #hd per cent4 ,pb1 pig lead being worth #d4ge at ,st4 ,louis4#f ,another pays #cb4be for #hj per cent4 ore1 or over1 deducting #ej;c4 per unit for ores assaying under #hj per cent4 ,another pays for #ij per cent4 of the lead content of the ore as shown by the assay1 at the ,st4 ,louis price of pig lead1 less a smelting charge of1 say1 #f to #h per ton of ore4 ,the history of the development of lead ore buying in the ,joplin district is rather curious4 ,in the early days of the district the ore was smelted wholly on ,scotch hearths1 which1 with the purest ores1 would yield #gj per cent4 metallic lead4 ,no account was taken of the lead in the rich slag1 chemical determinations being something unknown in the district at that time2 it being supposed generally that pure galena contained #gjj lb4 lead to the #ajjj lb4 of ore1 the value of #gjj lb4 lead1 less #d4ej per #ajjj lb4 of ore for freight and smelting costs1 was returned to the miner4 ,the buyers graded the ore1 according to their judgment1 by its appearance1 as to its purity and also as to its behavior in smelting2 an ore1 for example1 from near the surface1 imbedded in the clay and coated more or less with sulphate1 yielded its metal more freely than the purer galenas from deeper workings4 ,this was the origin of the present method of buying--a system that would hardly be tolerated except for the fact that the lead is1 as previously stated1 considered a by-product of zinc mining4 ,originally all the lead ore from the ,missouri-,kansas district was smelted in the same region1 either in the air furnace 7reverberatory sweating-furnace7 or in the water-back ,scotch hearth4 ,competition gradually developed in the market4 ,lead refiners found the pure sulphide of special value in the production of oxidized products4 ,some of the ore found its way to ,st4 ,louis1 and even as far away as ,colorado1 where it was used to collect silver4 ,since the formation of the ,american ,smelting and ,refining ,company and the greatly increased output of the immense deposits of lead ore in ,idaho1 no ,missouri lead ore has gone to ,colorado4 ,up to #aija1 one concern had more or less the control of the southwestern ,missouri ores4 ,at the present time1 lead ore is bought for smelters in ,joplin1 ,carterville1 and ,granby1 ,mo41 ,galena1 ,kan41 and ,collinsville1 ,ill41 and complaint is heard that present prices are really too high for the comfort of the smelters4 ,yet the old principle of paying for lead ores upon the supposed yield of #gj per cent41 irrespective of the real lead content1 is still largely in vogue4 ,any one interested in the matter will find it quite instructive to calculate the returning charges1 or gross profits1 in smelting these ores1 on the basis of #gj per cent4 recovery1 at #cb4be per #ajjj lb4 of ore1 less #ej;c4 per ton haulage1 with lead at #d4gg per #ajj lb4 at ,st4 ,louis4 ,no deduction1 it should be remarked1 is ever made for moisture in lead ores in this district4 ,it is of interest to observe that ,dr4 ,isaac ,a4 ,hourwich estimates 7in the ,u4 ,s4 ,census ,special ,report on ,mines and ,quarries recently issued7 the average lead contents of the soft lead ores of ,missouri in #aijb at #fh4b per cent41 taking as a basis the returns from five leading mining and smelting companies of ,missouri1 which reported a product of #gj1dia tons of lead from #ajc1dbh tons of their own and purchased ore4 ,the average prices for lead ore in #aijb were reported as follows1 per #ajjj lb43 ,illinois1 #ai4ec2 ,iowa1 #bd4dh2 ,kansas1 #bc4ea2 ,missouri1 #bb4ag2 ,wisconsin1 #bc4bi2 ,rocky ,mountain and ,atlantic ,coast ,states1 #aj4ij4 ,in #aijc1 according to ,ingalls 78,the ,mineral ,industry10 ,vol4 ,,xii71 the ore from the ,joplin district commanded an average price of #ec per #bjjj lb41 while the average in the southeastern district was #df4ha4 ,,part ,,ii ,,roast-,,reaction ,,smelting ,,scotch ,,hearths ,,and ,,reverberatory ,,furnaces ,,lead ,,smelting ,,in ,,the ,,scotch ,,hearth ,,by ,,kenneth ,w4 ,m4 ,,middleton 7,july #f1 #aije7 ,in view of the fact that the ,scotch hearth in its improved form is now coming to the front again to some extent in lead smelting1 it may prove interesting to give a brief account of its present use in the north of ,england4 ,admitting that1 where preliminary roasting is necessary1 the best results can be obtained with the water-jacketed blast furnace 7this being more especially the case where labor is an expensive item71 we have still as an alternative the method of smelting raw in the ,scotch hearth4 ,at one works1 which ,i recently visited1 all the ore was smelted raw2 at another1 all the ore received a preliminary roast1 and it is instructive to compare the results obtained in the two cases4 ,the following data refer to a fairly 8free-smelting0 galena assaying nearly #hj per cent4 of lead4 ,when smelting raw ore in the hearth1 fully #g long tons can be treated in #bd hours1 the amount of lead produced direct from the furnace in the first fire being #hdjj to #ijjj lb42 this is equivalent to #ef to #fj per cent4 of lead1 the remaining #bd to #bj per cent4 going into the fume and the slag4 ,when smelting ore which has received a preliminary roast of two hours1 #ab1jjj lb4 of lead is produced direct from the hearth1 this being equivalent to #fe per cent4 of the ore4 ,when the ore is roasted1 the output of the hearth is practically the same for all ores of equal richness2 but when smelting raw1 if the galena is finely divided1 the output may fall much below that given herewith2 while1 on the other hand1 under the most favorable conditions it may rise to #ab1jjj lb4 in #bd hours1 or even more4 ,i had an opportunity of seeing a parcel of galena carrying #hd per cent4 of lead 7but broken down very fine7 smelted raw4 ,the ore was kept damp and the blast fairly low2 but1 in spite of that1 a quantity of the ore was blown into the flue1 and only #eajj lb4 of lead was produced from the hearth in #bd hours4 ,galena carrying only #fe per cent4 of lead does not give nearly as satisfactory results when smelted raw in the hearth2 barely six tons of ore can be smelted in #bd hours1 and only #dejj to #edjj lb4 of lead can be produced directly4 ,this is equivalent to1 say1 #dc per cent4 of the ore in the first fire2 the remaining #bb per cent4 goes into the slag or to the flue as fume4 ,moreover1 the #fe per cent4 ore requires #aejj lb4 of coal in #bd hours1 while the #hj per cent4 galena uses only #ajjj lb4 ,turning now for a moment to the costs of smelting raw and of smelting after a preliminary roast1 we find that 7in the case of the two works we have been considering7 the results are all in favor of smelting raw1 so far as a galena carrying nearly #hj per cent4 is concerned4 ,the cost of smelting1 per ton of lead produced1 is given herewith3 ,,ore ,,smelted ,,raw ,smelters' wages #b4jd 8 coal 7#dbe lb47 #j4ch ----- ,total #b4db ,a very small quantity of lime is also used in this case for some ores1 but its cost would never amount to more than #d;c4 per ton of lead produced4 ,,ore ,,receiving ,a ,,preliminary ,,roast ,roasters' wages #j4fa 8 coal 7#dbe lb47 #j4fe ,smelters' wages #a4jh 8 coal 7#ge lb47 #j4aa ,peat and lime #j4jh ----- ,total #b4ec ,it should be noted also that the smelters at the works where the ore was not roasted receive higher pay4 ,in the eight-hour shift they produce about #a tons of lead2 and as there are two of them to a furnace1 they make #c4jf between them1 or #a4ec each4 ,the two men smelting roasted ore produce about two tons in an eight-hour shift1 and therefore each receives #a4jh per shift4 ,coming now to fume-smelting in the hearth1 we can again compare the results obtained in smelting raw and after roasting4 ,it is well to bear in mind1 also1 that1 while only #f per cent4 of the lead goes in the fume when smelting roasted ores in the hearth1 a considerably larger proportion is thus lost when smelting raw ores4 ,when fume is smelted raw1 it is best dealt with when containing about #dj per cent4 of moisture4 ,one man attends to the hearth 7instead of two as when smelting ore71 and in #bd hours #cjjj lb4 of lead is produced1 the amount of coal used being #bajj lb4 ,no lime is required4 ,when smelting roasted fume1 two men attend to the hearth and the output is #fjjj lb4 in #bd hours1 the amount of coal used being #ahjj lb4 ,in this latter case fluorspar happens to be available 7practically free of cost71 and a little of it is used with advantage in fume-smelting1 as well as a small quantity of lime4 ,the cost of fume-smelting per ton of lead produced is given herewith3 ,,fume ,,smelted ,,raw ,smelters' wages #b4hh 8 coal 7#adjj lb47 #b4ac -------- ,total #e4ja ,,fume ,,receiving ,a ,,preliminary ,,roast ,roasters' wages #b4jh 8 coal 7#adej lb47 #b4ah ,smelters' wages #b4jd 8 coal 7#fjj lb47 #j4ib ,peat and lime #j4jh -------- ,total #g4cj ,in this case1 as in that of ore1 the smelter of the raw fume gets better pay2 he has #a4dd per eight-hour shift1 while the smelter of the roasted ore has only #a4jb per eight-hour shift4 ,fume takes four hours to roast1 as compared to the two hours taken by ore4 ,from these facts regarding ,scotch-hearth smelting1 it would seem that with galena carrying1 say1 over #gj per cent4 lead 7but more especially with ore up to #hj per cent4 in lead1 and1 moreover1 fairly free from impurities detrimental to 8free0 smelting71 very satisfactory results can be obtained by smelting raw4 ,against this1 however1 it must be said that at the works where the ore is roasted attempts at smelting raw have been made several times without sufficient success to justify the adoption of this method1 although the ores smelted average #ge per cent4 lead and seem quite suitable for the purpose4 ,probably this may be accounted for by the fact that the method of running the furnace when raw ore is being smelted is rather different from that adopted when dealing with roasted ore4 ,moreover1 at the works under notice the furnaces are not of the most modern construction2 and1 as the old custom of dropping a peat in front of the blast every time the fire is made up still survives1 it is necessary to shut off the blast while this is being done1 and the fire is then apt to get rather slack4 ,the gray slag produced in the hearth is smelted in a small blast furnace1 a little poor fume1 and sometimes a small quantity of fluorspar1 being added to facilitate the process4 ,some figures regarding slag-smelting may be of interest4 ,the slag-smelters produce #ijjj lb4 of lead in #bd hours4 ,the cost of slag-smelting per ton of lead produced is as follows3 ,smelters' wages #a4fj ,coke 7#aejj lb47 #c4db ,peat #j4jf -------- ,total #e4jh ,recent analyses of ,weardale 7,durham county7 lead smelted in the ,scotch hearth1 and slag-lead smelted in the blast furnace1 are given herewith3 ,,fume-,,lead ,,from ,,silver-,,lead ,,from ,,slag-,,lead ,,from ,,hearth ,,hearth ,,blast ,,furnace ,lead #ii4ieg #ii4ieg #ii4jac ,silver #j4jjce #j4jbjj #j4jadb 7#aoz4 #b;dwt4 #ba;gr4 7#foz4 #aj;dwt4 #af;gr4 7#doz4 #ab;dwt4 #ah;gr4 per ,long ,ton7 per ,long ,ton7 per ,long ,ton7 ,tin nil nil nil ,antimony nil nil #j4hgd ,copper nil nil #j4jbd ,iron #j4jai #j4jai #j4jbc ,zinc nil nil nil #ii4igie #ii4iifj #ii4idhb ,the ordinary form of the ,scotch hearth is probably too well known to need much description4 ,the dimensions which have been found most suitable are as follows3 ,front to back1 #ba in42 width1 #bg in42 depth of hearth1 #h to #ab in4 ,formerly the distance from front to back was #bd in41 but this was found too much for the blast and for the men4 ,the cast-iron hearth which holds the molten lead is set in brickwork2 if #h in4 deep and capable of holding about ton of lead1 it is quite large enough4 ,the workstone or inclined plate in front of the hearth is cast in one piece with it1 and has a raised holder on either side at the lower edge1 and a gutter to convey the overflowing lead to the melting-pot4 ,the latter is best made with a partition and an opening at the bottom through which clean lead can run1 so that it can be ladled into molds without the necessity for skimming the dross off the surface4 ,it is well also to have a small fireplace below the melting-pot4 ,on each side of the hearth1 and resting on it1 is a heavy cast-iron block1 #i in4 thick1 #ae in4 high1 #bg to #bh in4 long4 ,to save metal1 these are now cast hollow and air is caused to pass through them4 ,on the back of the hearth stands another cast-iron block known as the 8pipestone10 through which the blast comes into the furnace4 ,in the older forms of pipestone the blast comes in through a simple round or oval pipe1 a common size being #c or #d in4 wide by #b in4 high1 and the pipestone is not water-cooled4 ,with this construction the hearth will not run satisfactorily unless the pipestone is set with the greatest care1 so as to have the tuyere exactly in the center1 and as there is no water-cooling the metal quickly burns away when fume is being smelted4 ,moreover1 the blast is apt to be stopped by slag adhering to the end of the pipe4 ,as already mentioned1 a peat is dropped in front of the blast every time the fire is made up1 with the object of keeping a clear passage open for the blast4 ,this old custom has1 however1 several serious disadvantages2 first1 it prevents the blast being kept on continuously2 and1 second1 it makes it necessary to have the hearth open at the top so that the smelter-man can go in by the side of it4 ,in this case the ore is fed from the side by the smelter-man1 who works under the large hood placed above the furnace to carry away the fume4 ,even when he is engaged in shoveling back the fire from the front and is not underneath the hood1 it is impossible to prevent some fume from blowing out2 and there is much more liability to lead-poisoning than when the hearth is closed at the top by the chimney and the smelter-men work from the front4 ,the best arrangement is to have the hearth entirely closed in by the chimney1 except for the opening at the front1 and to have a small auxiliary flue above the workstone leading direct to the open air to catch any fume that may blow out past the shutter in front of the hearth4 ,in an improved form of pipestone1 a pipe connected to the blast-main fits into the semicircular opening at the back and is driven tight against a ridge in the flat side of the opening4 ,going through the pipestone1 the arch becomes gradually flatter1 and the blast emerges into the hearth1 about #b in4 above the level of the molten lead1 through an oblong slit #ab in4 long by #a in4 wide1 with a ledge projecting #a in4 immediately above it4 ,the back and front are similar1 so that when one side gets damaged the pipestone can be turned back to front4 ,water is conveyed in a #b in4 iron pipe to the pipestone1 and after passing through it is led away from the other end to a water-box1 which stands beside the hearth and into which the red-hot lumps of slag are thrown to safeguard the smelters from the noxious fumes4 ,on the top of the pipestone rests an upper backstone1 also of cast iron2 it extends somewhat higher than the blocks at the sides4 ,all this metal above the level of the lead is necessary because the partially fused lumps which stick to it have to be knocked off with a long bar1 so that if fire-bricks were used in place of cast iron they would soon be broken up and destroyed4 ,with a covered-in hearth1 when the ore is charged from the front1 the following is the method adopted in smelting raw ore3 ,the charge floats on the molten lead in the hearth1 and at short intervals the two smelters running the furnace ease it up with long bars1 which they insert underneath in the lead4 ,any pieces of slag adhering to the sides and pipestone are broken off4 ,after easing up the fire1 the lumps of partially reduced ore1 mixed with cinders and slag1 are shoveled on to the back of the fire2 the slag is drawn out upon the workstone 7any pieces of ore adhering to it being broken off and returned to the hearth71 and it is then quenched in a water-box placed alongside the workstone4 ,one or two shovelfuls of coal1 broken fairly small and generally kept damp1 are thrown on the fire1 together with the necessary amount of ore1 which is also kept damp if in a fine state of division4 ,it is part of the duty of the two smelters to ladle out the lead from the melting-pot into the molds4 ,in smelting ore a fairly strong1 steady blast is required1 and it is made to blow right through so as to keep the front of the fire bright4 ,a little lime is thrown on the front of the fire when the slag gets too greasy4 ,when smelting raw fume one man attends to the furnace4 ,it does not have to be made up nearly as frequently1 the work being easier for one man than smelting ore is for two4 ,the unreduced clinkers and slag are dealt with exactly as in smelting ore2 and coal is also1 in this case1 thrown on the back of the fire1 but the blast does not blow right through to the front4 ,on the contrary1 the front of the fire is kept tamped up with fume1 which should be of the coherency of a thick mud4 ,the blast is not so strong as that necessary for ore4 ,the idea is partially to bake the fume before submitting it to the hottest part of the furnace1 or to the part where the blast is most strongly felt4 ,it is only when smelting fume that it is necessary to keep the pipestone water-cooled4 ,to start a furnace takes from two to three hours4 ,the hearth is left full of lead1 and this has to be melted before the hearth is in normal working order4 ,drawing the fire takes about three-quarters of an hour2 the clinkers are taken off and kept for starting the next run1 and the sides and back of the hearth are cleaned down4 ,,the ,,federal ,,smelting ,,works1 ,,near ,,alton1 ,,ill4#g ,,by ,o4 ,,pufahl 7,june #b1 #aijf7 ,the works of the ,federal ,lead ,company1 near ,alton1 ,ill41 were erected in #aijb4 ,they have a connection with the ,chicago1 ,peoria ,st4 ,louis ,railway1 by which they receive all their raw materials1 and by which all the lead produced is shipped4 ,the ore smelted is galena1 with dolomitic gangue1 and a small quantity of pyrites 7containing a little copper1 nickel1 and cobalt7 from southeastern ,missouri1 and consists chiefly of fine concentrates1 containing #fj to #gj per cent4 lead4 ,in addition thereto a small proportion of lump ore is also smelted4 ,a striking feature at these works is the excellent facility for handling the materials4 ,the bins for the ore1 coke and coal are made of concrete and steel and are filled from cars running on tracks laid above them4 ,for transporting the materials about the works a narrow-gage railway with electric locomotives is used4 ,the ores are smelted by the ,scotch-hearth process4 ,there are #bj hearths arranged in a row in a building constructed wholly of steel and stone4 ,the sump 7#d #b #a ft47 of each furnace contains about one ton of lead4 ,the furnaces are operated with low-pressure blast from a main which passes along the whole row4 ,the blast enters the furnace from a wind chest at the back through eight #a in4 iron pipes1 #b in4 above the bath of lead4 ,the two sides and the rear wall are cooled by a cast-iron water jacket of #a in4 internal width4 ,two men work1 in eight-hour shifts1 at each of the furnaces1 receiving #d4ge and #d4be;c4 respectively for every #ajj lb4 of lead produced4 ,the ore is weighed out and heaped up in front of the furnaces2 on the track near by the coke is wheeled up in a flat iron car with two compartments4 ,the furnacemen are chiefly negroes4 ,at the side of each furnace is a small stock of coal1 which is used chiefly for maintaining a small fire under the lead kettle4 ,only small quantities of coal are added from time to time during the smelting operation4 ,over each furnace is placed an iron hood1 through which the fumes and gases escape4 ,they pass first through a collecting pipe1 extending through the whole works1 to a #aejj ft4 dust flue1 measuring #aj #aj ft41 in internal cross-section4 ,near the middle of this is placed a fan of #ajj1jjj cu4 ft4 capacity per minute1 which forces the fumes and gases into the bag-house1 where they are filtered through #aejj sacks of loosely woven cotton cloth1 each #be ft4 long and #ah in4 in diameter1 and thence pass up a #aej ft4 stack4 ,the dust recovered in the collecting flue is burnt1 together with the fume caught by the bags1 the coal which it contains furnishing the combustible4 ,it burns smolderingly and frits together somewhat4 ,the product 7chiefly lead sulphate7 is then smelted in a shaft furnace1 together with the gray slag from the hearth furnaces4 ,the total extraction of lead is about #ih per cent41 i4e41 the combined process of ,scotch-hearth and blast-furnace smelting yields #ih per cent4 of the lead contained in the crude ore4 ,the direct yield of lead from the ,scotch hearths is about #gj per cent4 ,they also produce gray slag1 containing much lead1 which amounts to about #be per cent4 of the weight of the ore4 ,about equal proportions of lead pass into the slag and into the flue dust4 ,when working to the full capacity1 with rich ore 7#hj per cent4 lead and more7 the #bj furnaces can produce about #bjj tons of lead in #bd hours4 ,the coke consumption in the hearth furnaces amounts to only #h per cent4 of the ore4 ,the lead from these furnaces is refined for #cj minutes to one hour by steam in a cast-iron kettle of #ce tons capacity1 and is cast into bars either alone or mixed with lead from the shaft furnace4 ,the 8,federal ,brand0 carries nearly #ii4i per cent4 lead1 #j4je to #j4a per cent4 copper1 and traces of nickel and cobalt4 ,the working up of the between products from the hearth-furnaces is carried out as follows3 ,slag1 burnt flue dust and roasted matte from a previous run1 together with a liberal proportion of iron slag 7from the iron works at ,alton71 are smelted in a #ab-tuyere blast furnace for work-lead and matte4 ,the furnace is provided with a lead well at the back4 ,the matte and slag are tapped off together at the front and flow through a number of slag pots for separation4 ,the shells which remain adhering to the walls of the pots on pouring out the slag are returned to the furnace4 ,all the waste slag 7containing about #j4e per cent4 lead7 is dumped down a ravine belonging to the territory of the smeltery4 ,the lead from the shaft furnace is liquated in a small reverberatory furnace1 of which the hearth consists of two inclined perforated iron plates4 ,the residue is returned to the shaft furnace1 while the liquated lead flows directly to the refining kettle1 which is filled in the course of four hours4 ,here it is steamed for about one hour and is then cast into bars through a ,steitz siphon1 after skimming off the oxide4 ,the matte is crushed and roasted in a reverberatory furnace 7#fj ft4 long74 ,the power plant comprises three ,stirling boilers and two #bej h4 p4 compound engines1 of which one is for reserve2 also one steam-driven dynamo1 coupled direct to the engine1 furnishing the current for the entire plant1 for the electric locomotives1 etc4 ,the coke is obtained from ,pennsylvania and costs about #d a ton1 while the coal comes from near-by collieries and costs #a per ton4 ,in the well-equipped laboratory the lead in the ores and slags is determined daily by ,alexander's 7molybdate7 method1 while the silver content of the lead 7a little over #a oz4 per ton7 is estimated only once a month in an average sample4 ,when the plant is in full operation it gives employment to #aej men4 ,cases of lead-poisoning are said to occur but rarely1 and then only in a mild form4 ,,lead ,,smelting ,,at ,,tarnowitz 7,september #bc1 #aije7 ,the account of the introduction of the ,huntington-,heberlein process at ,tarnowitz1 ,prussia1 published elsewhere in this issue1 is of peculiar interest inasmuch as it tells of the complete displacement by the new process of one of the old processes of lead smelting which had become classic in the art4 ,the roast-reaction process of lead smelting1 especially as carried out in reverberatory furnaces1 has been for a long time decadent1 even in ,europe4 ,tarnowitz was one of the places where it survived most vigorously4 ,outside of ,europe1 this process never found any generally extensive application4 ,it was tried in the ,joplin district1 and elsewhere in ,missouri1 with ,flintshire furnaces in the seventies4 ,later it was employed with modified ,flintshire and ,tarnowitz furnaces at ,desloge1 in the ,flat ,river district of ,missouri1 where the plant is still in operation1 but on a reduced scale4 ,the roast-reaction process of smelting1 as practised at ,tarnowitz1 was characterized by a comparatively large charge1 slow roasting and low temperature1 differing in these respects from the ,carinthian and ,welsh processes4 ,it was not aimed to extract the maximum proportion of lead in the reverberatory furnace itself1 the residue therefrom1 which inevitably is high in lead1 being subsequently smelted in the blast furnace4 ,ores too low in lead to be suitable for the reverberatory smelting were sintered in ordinary furnaces and smelted in the blast furnace together with the residue from the other process4 ,in both of these processes the loss of lead was comparatively high4 ,one of the most obvious advantages of the ,huntington-,heberlein process is its ability to reduce the loss of lead4 ,the result in that respect at ,tarnowitz is clearly stated by ,mr4 ,biernbaum1 whose paper will surely attract a good deal of attention4#h ,,lead ,,smelting ,,in ,,reverberatory ,,furnaces ,,at ,,desloge1 ,,mo4 ,,by ,,walter ,,renton ,,ingalls 7,december #af1 #aije7 ,the roast-reaction method of lead smelting in reverberatory furnaces never found any general employment in the ,united ,states1 although in connection with the rude air-furnaces it was early introduced in ,missouri4 ,the more elaborate ,flintshire furnaces were tried at ,granby1 in the ,joplin district1 but they were displaced there by ,scotch hearths4 ,the most extensive installation of furnaces of the ,flintshire type was made at ,desloge1 in the ,flat ,river district of southeastern ,missouri4 ,this continued in full operation until #aijc1 when the major portion of the plant was closed1 it being found more economical to ship the ore elsewhere for smelting4 ,however1 two furnaces have been kept in use to work up surplus ore4 ,as a matter of historic interest1 it is worth while to record the technical results at ,desloge1 which have not previously been described in metallurgical literature4 ,the ,desloge plant1 which was situated close to the dressing works connected with the mine1 and was designed for the smelting of its concentrate1 comprised five furnaces4 ,the furnaces were of various constructions4 ,the oldest of them was of the ,flintshire type1 and had a hearth #aj ft4 wide and #ad ft4 long4 ,the other furnaces were a combination of the ,flintshire and ,tarnowitz types4 ,they were built originally like the newer furnaces at ,tarnowitz1 ,upper ,silesia1 with a rather large rectangular hearth and a lead sump placed at one side of the hearth near the throat end2 but good results were not obtained from that construction1 wherefore the furnaces were rearranged with the sump at one side1 but in the middle of the furnace1 as in the ,flintshire form4 ,the rectangular shape of the ,tarnowitz hearth was1 however1 retained4 ,furnaces thus modified had hearths #aa ft4 wide and #af ft4 long1 except one which had a hearth #ac ft4 wide4 ,the same quantity of ore was put through each of these furnaces1 the increase in hearth area being practically of no useful effect1 because of inability to attain the requisite temperature in all parts of the larger hearths with the method of heating employed4 ,the men objected especially to a furnace with hearth #ac ft4 wide1 which it was found difficult to keep in proper condition1 and also difficult to handle efficiently4 ,even the width of #aa ft4 was considered too great1 and preference was expressed for a #aj ft4 width4 ,in this connection1 it may be noted that the old furnaces at ,tarnowitz were #aa ft4 #i in4 long and #aj ft4 #aj in4 wide1 while the new furnaces were #af ft4 long and #h ft4 #aj in4 wide 7,hofman1 8,metallurgy of ,lead10 fifth edition1 p4 #aab74 ,all of these dimensions were exceeded at ,desloge4 ,the ,flintshire furnaces at ,desloge had three working doors per side2 the others had four1 but only three per side were used1 the doors nearest the throat end being kept closed because of insufficient temperature in that part of the furnace4 ,the furnace with hearth #aa #ad ft4 had a grate area of #f4e #c ft4 #ai4e sq4 ft42 the #aa #af furnaces had grates #h #c #bd ft4 sq4 ,the ratios of grate to hearth area were therefore approximately #a3h and #a3g4c1 respectively4 7,compare with ratio of #a3aj at ,tarnowitz1 and #a3f at ,stiperstones47 ,the ash pits were open from behind in the customary ,english fashion4 ,the grate bars were cast iron1 #cf in4 long4 ,the bars were #a in4 thick at the top1 with in4 spaces between them4 ,the open spaces were #cb in4 long1 including the rib in the middle4 ,the bars were #d in4 deep at the middle and #b in4 at the ends4 ,the distance from the surface of the grate bars to the fire-door varied in the different furnaces4 ,some of those with hearths #aa #af ft4 and grates #h #c ft4 had the bars #f in4 below the fire-door2 in others the bars were almost on a level with the fire-door4 ,the furnaces were run with a comparatively thin bed of coal on the grate1 and combustion was very imperfect1 the percentage of unburned carbon in the ash being commonly high4 ,this was unavoidable with the method of firing employed and the inferior character of the coal 7southern ,illinois74 ,the excessive consumption of coal was due largely1 however1 to the practice of raking out the entire bed of coal at the beginning of the operation of 8firing down0 7beginning the reaction period71 when a fresh fire was built with cordwood and large lumps of coal4 ,each furnace had two flues at the throat1 #af #ah in4 in size1 each flue being provided with a separate damper4 ,each furnace had an iron chimney approximately #ee ft4 high1 of which #ac ft4 was a brick pedestal 7#fd #fd in47 and the remaining #db ft4 sheet steel1 guyed4 ,the chimneys were #db in4 in diameter4 ,the distance from the outside end of the furnace to the chimney was approximately #f ft41 and there was consequently but little opportunity for flue dust to collect in the flue4 ,about once a month1 however1 the chimney was opened at the base and about two wheelbarrows 7say #fjj lb47 of flue dust1 assaying about #ej per cent4 lead1 was recovered per furnace4 ,the furnace house was a frame building #de ft4 wide1 with boarded sides and a corrugated-iron pitch roof1 supported by steel trusses4 ,the furnaces were set in this house1 side by side1 their longitudinal axes being at right angles to the longitudinal axis of the building4 ,the distance from the outside of the fire-box end of the furnace to the side of the building was #aj ft4 ,the coal was unloaded from a railway track alongside of the building and was wheeled to the furnace in barrows4 ,some of the furnaces were placed #ah ft4 apart2 others #bb ft4 apart4 ,the men much preferred the greater distance1 which made their work easier1 an important consideration in this method of smelting4 ,the hight from the floor to the working door of the furnace was approximately #cf in4 ,the working doors were formed with cast-iron frames1 making openings #g #aa in4 on the inside and #ae #bh in4 on the outside4 ,on the side of the furnace opposite the middle working door was placed a cast-iron hemispherical pot1 set partially below the floor-line4 ,this pot was #af in4 deep and #bd in4 in diameter2 the metal was in4 thick4 ,the distance from the top of the pot to the line of the working door was #ca in42 from the top of the pot to the bottom of the tap-door was #g in4 ,the tap-door was #d in4 wide and #i in4 high1 opening through a cast-iron plate #a in4 thick4 ,below the tap-door and on a line with the upper rim of the pot was a tap-hole #c in4 in diameter4 ,the frames of the working doors had lugs in front1 against which the buckstaves bore1 to hold the frames in position4 ,all other parts of the sides of the furnace1 including the fire-box1 were cased with in4 cast-iron plates1 which were obviously too light1 being badly cracked4 ,the cost of a furnace when built in #ahic was approximately #adjj1 not including the chimney2 but with the increased cost of material the present expense would probably be about #bjjj4 ,notwithstanding the light construction of the furnaces1 repairs were never a large item4 ,once a month a furnace was idle about #bd hours while the throat was being cleaned out1 and every two months some repairing1 such as relining the fire-boxes1 etc41 was required4 ,if repairs had to be made on the inside of the furnace1 two days would be lost while it was cooling sufficiently for the men to enter4 ,in refiring a furnace1 from #h to #ab hours was required to raise it to the proper temperature4 ,out of the #cfe days of the year1 a furnace would lose from #bj to #be days1 for cleaning the throat and making repairs to the fire-box1 arch1 etc4 ,when a furnace was run with two shifts the schedule of operation was as follows3 ,drop charge #d a4m4 ,begin work #g a4m4 ,begin firing down #aa a4m4 ,begin first tapping #a p4m4 ,rake out slag #b4cj p4m4 ,begin second tapping #c p4m4 ,drop charge #d p4m4 ,begin working #e4cj p4m4 ,begin firing down #aa p4m4 ,begin first tapping #a a4m4 ,rake out slag #b4cj a4m4 ,begin second tapping #c p4m4 ,with three shifts on a furnace1 the schedule was as follows3 ,drop charge #g a4m4 ,begin firing down #ab a4m4 ,begin tapping #a p4m4 ,rake out slag #b p4m4 ,begin tapping #b4cj p4m4 ,drop charge #c p4m4 ,begin firing down #h p4m4 ,begin tapping #i p4m4 ,rake out slag #aj p4m4 ,begin tapping #aj4cj p4m4 ,drop charge #aa4jj p4m4 ,begin firing down #d a4m4 ,begin tapping #e a4m4 ,rake out slag #f a4m4 ,begin tapping #f4cj a4m4 ,the hearths were composed of about #h in4 of gray slag beaten down solidly on a basin of brick1 which rested on a filling of clay1 rammed solid4 ,the hearth was patched if necessary after the drawing of each charge4 ,the system of smelting was analogous to that which was practiced in ,wales rather than to the ,silesian1 the charges being worked off quickly1 and with the aim of making a high extraction of lead directly and a gray slag of comparatively low content in lead4 ,the average furnace charge was #cejj lb4 ,at the beginning of the reaction period about #he to #ajj lb4 of crushed fluorspar was thrown into the furnace and mixed well with the charge4 ,the furnace doors were then closed tightly and the temperature raised1 the grate having previously been cleaned4 ,at the first tapping about #abjj lb4 of lead would be obtained4 ,a small quantity of chips and bark was thrown into the lead in the kettle1 which was then poled for a few minutes1 skimmed1 and ladled into molds1 the pigs weighing #hj lb4 ,the skimmings and dross were put back into the furnace4 ,the pig lead was sold as 8ordinary soft ,missouri40 ,the gray slag was raked out of the furnace1 at the end of the operation1 into a barrow1 by which it was wheeled to a pile outside of the building4 ,shipments of the slag were made to other smelters from time to time1 #ie per cent4 of its lead content being paid for when its assay was over #dj per cent41 and #ij per cent4 when lower4 ,each furnace was manned by one smelter 7#a4ge7 and one helper 7#a4ee7 per shift1 when two shifts per #bd hours were run4 ,they had to get their own coal1 ore and flux1 and wheel away their gray slag and ashes4 ,in winter1 when three shifts were run1 the men were paid only #a4fe and #a4ej respectively4 ,there was a foreman on the day shift1 but none at night4 ,the total coal consumption was ordinarily about #j4h to #j4i per ton of ore4 ,run-of-mine coal was used1 which cost about #b per ton delivered4 ,the coal was of inferior quality1 and it was wastefully burned1 as previously referred to1 wherefore the consumption was high in comparison with the average at ,tarnowitz1 where it used to be about #j4e per ton of ore4 ,the chief features of the practice at ,desloge are compared with those at ,tarnowitz1 ,silesia and ,holywell 7,flintshire71 and ,stiperstones 7,shropshire71 ,wales1 in the following table1 the data for ,silesia and ,wales being taken from ,hofman's 8,metallurgy of ,lead10 fifth edition1 pp4 #aab1 #aac4 ,,detail ,,holywell ,,stiper-,,tarnowitz,,tarnowitz ,,desloge ,,stones ,hearth length1 ft4 #ab4jj #i4ge #aa4ge #af4jj #af4jj ,hearth width1 ft4 #i4ej #i4ej #aj4hc #h4hc #aa4jj ,grate length1 ft4 #d4ej #d4ej #h4jj #h4jj #h4jj ,grate width1 ft4 #b4ej #b4ej #a4fg #a4fg #c4jj ,grate area3 hearth area #a3h #a3f #a3aj #a3aj #a3g ,charges per #bd hr41 #c #c #b #b #c ,ore smelted per #bd hr41 lb4 #g1jej #g1jej #h1hjj #af1ejj #aj1ejj ,assay of ore1 ,pb #ge-hj #gg4e #gj-gd #gj-gd #gj ,gray slag1 of charge #ab #ae #cj #bg ,gray slag1 ,pb #ee #ch4h #ef #ch ,men per #bd hr4 #f #d #d #f #f ,coal used per ton ore #j4eg-j4gf #j4ef #j4df #j4ej #j4ij ,the regular furnace charge at ,desloge was #cejj lb4 ,the working of three charges per #bd hours gave a daily capacity of #aj1ejj lb4 per furnace4 ,these figures refer to the wet weight of the concentrate1 which was smelted just as delivered from the mill4 ,its size was #i mm4 and finer4 ,assuming its average moisture content to be #e per cent41 the daily capacity per furnace was about #aj1jjj lb4 7#e tons7 of dry ore4 ,the metallurgical result is indicated by the figures for two months of operation in #aijj4 ,the quantity of ore smelted was #ajab tons1 equivalent to approximately #ifb tons dry weight4 ,the pig lead produced was #ebc4c tons1 or #ed4d per cent4 of the weight of the ore4 ,the gray slag produced was #bfb4be tons1 or about #bg per cent4 of the weight of the ore4 ,the assay of the ore was approximately #gj per cent4 lead1 giving a content of #fgc4d tons in the ore smelted4 ,the gray slag assayed approximately #ch per cent4 lead1 giving a content of #ii4ff tons4 ,assuming that #ij per cent4 of the lead in the gray slag be recoverable in the subsequent smelting in the blast furnace1 or #hi4g tons1 the total extraction of lead in the process was #ebc4c #hi4g #fgc4d #ia per cent4 ,the metallurgical efficiency of the process was1 therefore1 reasonably high1 especially in view of the absence of dust chambers4 99 99 99 99 99 ,the cost of smelting with five furnaces in operation1 each treating three charges per day1 was approximately as follows3 #a foreman at #c #c4jj #e furnace crews at #i4ij #di4ej ,unloading #ba tons of coal at #f;c4 #a4bf ,loading #ad tons lead at #ae;c4 #b4aj 8 #g tons gray slag at #ae;c4 #a4je ------------ ,total labor #ef4ia #ba tons coal at #b #db4jj ,flux and supplies #ac4jj ,blacksmithing and repairs #aj4jj ------------ ,total #aba4ia ,on the basis of #f4be tons of wet ore1 this would be #d4fe per ton4 ,the actual cost in seven consecutive months of #aijj was as follows3 ,labor1 #a4ih per ton2 coal1 #a4hf2 flux and supplies1 #j4ea2 blacksmithing and repairs1 #j4ci2 miscellaneous1 #j1jag2 total1 #d4geg4 ,if the cost of smelting the gray slag be reckoned at #h per ton1 and the proportion of gray slag be reckoned at #j4be ton per ton of galena concentrate1 the total cost of treatment of the latter comes to about #f4ge per ton of wet charge1 or about #g per ton of dry charge4 ,this cost could be materially reduced in a larger and more perfectly designed plant4 ,the practice at ,desloge did not compare unfavorably1 either in respect to metal extracted or in smelting cost1 with the roast-reduction method of smelting or the ,scotch hearth method1 as carried out in the plants of similar capacity and approximately the same date of construction1 smelting the same class of ore1 but the larger and more recent plants in the vicinity of ,st4 ,louis could offer sufficiently better terms to make it advisable to close down the ,desloge plant and ship the ore to them4 ,one of the drawbacks of the reverberatory method of smelting was the necessity of shipping away the gray slag1 the quantity of that product made in a small plant being insufficient to warrant the operation of an independent shaft furnace4 ,,part ,,iii ,,sintering ,,and ,,briquetting ,,the ,,desulphurization ,,of ,,slimes ,,by ,,heap ,,roasting ,,at ,,broken ,,hill#i ,,by ,e4 ,j4 ,,horwood 7,august #bb1 #aijc7 ,it is well known that1 owing to the intimate mixture of the constituents of the ,broken ,hill sulphide ores1 a great deal of crushing and grinding is required to detach the particles of galena from the zinc blende and the gangue2 and it will be understood1 therefore1 that a considerable amount of the material is converted into a slime which consists of minute but well-defined particles of all the constituents of the ore1 the relative proportions of which depend on the dual characteristics of hardness and abundance of the various constituents4 ,an analysis of the slime shows the contents to be as follows2 ,galena 7,pb,s7 #bd4jj ,blende 7,zn,s7 #bi4jj ,pyrite 7,fe,s7 #c4ch ,ferric oxide 7,fe,o7 #d4ag ,ferrous oxide 7,fe,o7 contained in garnets #a4jc ,oxide of manganese 7,mn,o7 contained in rhodonite and garnets #f4ff ,alumina 7,al,o7 contained in kaolin and garnets #e4dj ,lime 7,ca,o7 contained in garnets1 etc4 #c4dj ,silica 7,si,o7 #bb4ih ,silver 7,ag7 4#jf ------------ #ajj4dh ,galena1 being the softest of these1 is found in the slimes to a larger extent than in the crude ore2 it is also1 for the same reason1 in the finest state of subdivision1 as is well illustrated by the fact that the last slime to settle in water is invariably much the richest in lead1 while the percentages of the harder constituents1 zinc blende and gangue1 show a corresponding reduction in quantity1 by reason of their being generally in larger sized particles and consequently settling earlier4 ,the fairly complete liberation of each of the constituent minerals of the ore that takes place in sliming tends1 of course1 to help the production of a high-grade concentrate by the use of tables and vanners1 and undoubtedly a fair recovery of lead is quite possible1 even with existing machines1 in the treatment of fine slimes2 but1 owing to the great reduction in the capacity of the machines1 which takes place when it is attempted to carry the vanning of the finer slimes too far1 and the consequently greatly increased area of the machines that would be necessary1 the operation1 sooner or later1 becomes unprofitable4 ,the extent to which the vanner treatment of slimes should be carried is1 of course1 less in the case of those mines owning smelters than with those which have to depend on the sale of concentrates as their sole source of profit4 ,in the case of the ,proprietary ,company1 all slime produced in crushing is passed over the machines after classification4 ,a high recovery of lead in the form of concentrates is1 of course1 neither expected nor obtained1 for reasons already explained2 but the finest lead-bearing slimes are allowed to unite with the tailings1 which are collected from groups of machines1 and are then run into pointed boxes1 where1 with the aid of hydraulic classification1 the fine rich slimes are washed out and carried to settling bins and tanks1 where the water is stilled and allowed to deposit its slime1 and pass over a wide overflow as clear water4 ,the slime thus recovered amounts to over #abjj tons weekly1 or about #aa per cent41 by weight1 of the ore1 and assays about #bj per cent4 lead1 #ag per cent4 zinc1 and #ah oz4 silver1 and represents1 in lead value1 about #aa per cent4 of the original lead contents of the crude ore and rather more than that percentage in silver contents4 ,these slimes are thus a by-product of the mills1 and their production is unavoidable2 but as they are not chargeable with the cost of milling1 they are an asset of considerable value1 more especially so since it has been demonstrated that they can be desulphurized sufficiently for smelting purposes by a simple operation1 and1 at the same time1 converted into such a physical condition as renders the material well suited for smelting1 owing to its ability to resist pressure in the furnaces4 ,the ,broken ,hill ,proprietary ,company has many thousands of tons of these slimes which the smelters have hitherto been unable to cope with1 owing to the roasters being fully occupied with the more valuable concentrates4 ,moreover1 the desulphurization of slimes in ,ropp mechanical roasters is objectionable for various reasons1 namely1 owing to the large amount of dust created with such fine material1 resulting injuriously to the men employed2 also on account of the reduction in the capacity of the roasters1 and consequent increase in working cost1 owing to the lightness of the slime1 especially when hot1 as compared with concentrates1 and the necessity for limiting the thickness of material on the bed of the roasters to a certain small maximum4 ,further1 the desulphurization of the slimes is no more complete with the mechanical roasters than in the case of heap roasting1 and the combined cost of roasting and briquetting being quite three shillings 7or #ge;c47 per ton in excess of the cost of heap roasting1 the latter possesses many advantages4 ,these heaps are being dealt with1 preparatory to roasting1 by picking down the material in lumps of about #e in4 in thickness1 while the fine dry smalls1 unavoidably produced1 are worked up in a pug mill with water1 and dealt with in the same way as the wet slime produced from current work4 ,the slime1 as produced by the mills1 is run from bins into railway trucks in a semi-fluid condition1 and shortly after being tipped alongside one of the various sidings on the mine is in a fit condition to be cut with shovels into rough bricks1 which dry with fair rapidity1 and when required for roasting are easily reloaded into railway trucks4 ,as each man can cut about #bj tons of bricks per day1 the cost is small4 ,various other methods of lumping the slime were tried1 including trucking the semi-fluid material on movable trams1 alongside which were set laths1 about #i in4 apart1 which enabled long slabs to be formed #i in4 wide and #e in4 thick1 which were1 after drying1 picked up in suitable lumps and loaded in platform trucks1 thence on railway trucks4 ,owing to the inferior roasting that takes place with bricks having flat sides1 which are liable to come into close contact in roasting1 and to the rather high labor cost1 this method was discontinued4 ,another method was to allow the slime to dry partially after being emptied from railway trucks1 and to break it into lumps by means of picks2 but this method entailed the making of an increased amount of smalls1 besides taking up more siding room1 owing to the extra time required for drying1 as compared with the method now in use4 ,ordinary bricking machines could1 of course1 be used1 but when the cost of handling the slime before and after bricking is counted1 the cost would be greater than with the simple method now in use2 the material being in too fluid a condition for making into bricks until some time elapses for drying1 a double handling would be necessitated before sending it to the bricking machine4 ,if1 however1 the slime could be allowed time to dry sufficiently in the trucks1 bricking by machinery would probably be preferable4 ,rather more than #aj per cent4 of smalls is made in handling the lumps in and out of the railway trucks1 and this is1 as already noted1 worked up with water in a pug mill at the sintering works1 and used partly for covering the heaps with slime to exclude an excessive amount of air4 ,the balance is thrown out and cut into bricks1 as already described4 ,at the heaps the lumps are at present being thrown from one man to another to reach their destination in the heap1 but the sidings have been laid out in duplicate with a view to enabling traveling cranes to be used on the line next the heap1 the lumps to be loaded primarily into wooden skips fitting the trucks4 ,it is probable1 however1 that the lumps will require to be handled out of the skips into their place in the heap1 as the brittle nature of the material may be found to render automatic tipping impracticable4 ,a considerable saving in labor would nevertheless accompany the use of cranes1 which would likewise be advantageous in loading the sintered material4 ,in order to reduce the inconvenience arising from fumes1 length is very desirable in siding accommodation1 so that heap building may be carried on at a sufficient distance from the burning kilns4 ,it is for the same reason preferable to build in a large tonnage at one time1 lighting the heaps altogether4 ,as the heaps burn about two weeks only1 long intervals intervene1 during which the fumes are absent4 ,in the experimental stages of slime roasting1 fuel1 chiefly wood1 was used in quantities up to #e per cent41 and was placed on the ground at the bottom of the heap1 where also a number of flues1 loosely built bricks1 were placed for the circulation of air4 ,the amount of fuel used has1 however1 been gradually reduced1 until the present practice of placing no fuel whatever in the bottom was arrived at2 but instead less than #a per cent4 of wood is now burned in small enlargements of the flues1 under the outer portion of the pile1 and placed about #ab ft4 apart at the centers4 ,this is found to be sufficient to start the roasting operation within #bd hours of lighting1 after which no further fuel is necessary4 ,as regards the dimensions of the heaps1 the width found most suitable is #bb ft4 at the base1 the sides sloping up rather flatter than one to one1 with a flat section on top reaching about #g ft4 in hight4 ,as there is always about #f in4 of the outer crust imperfectly roasted1 it is advisable to make the length as great as possible1 thus minimizing the surface exposed4 ,the company is building heaps up to #bjjj ft4 long4 ,during roasting care is required to regulate the air supply1 the object being to avoid too fierce a roast1 which tends to sinter and partially fuse the material on the outer portions of the lumps1 while inside there is raw slime4 ,by extending the roast over a longer period this is avoided1 and a more complete desulphurization is effected4 ,experiments conducted by ,mr4 ,bradford1 the chief assayer1 demonstrated that1 at a temperature of #djj deg4 ,c41 the sulphide slime is converted into basic sulphate1 while at a temperature of #hjj deg4 ,c4 the material becomes sintered owing to the decomposition of the basic sulphate and the formation of fusible silicate of lead4 ,in practice1 the sulphur contents of the material1 which originally are about #ad per cent41 become reduced to from #f4e to #h4e per cent41 half in the form of basic sulphate and half as sulphides2 much of the material sinters and becomes matted together in a fairly solid mass4 ,the heaps are built without chimneys of any kind2 a strip about #e ft4 wide along the crest of the pile is left uncovered by plastered slime1 and this1 together with the open way in which the lumps are built in1 allows a natural draft to be set up1 which can be regulated by partly closing the open ends of the flues at the base of the pile4 ,masonry kilns were used in the earlier stages with good results1 which1 however1 were not so much better than those obtained by the heap method as to justify the expense of building1 taking into consideration1 too1 the extra cost of handling the roasted material in the necessarily more confined space4 ,much interest has been taken in the chemical reactions which take place in the operation of desulphurization of these slimes1 it being contended1 on the one hand1 that the unexpectedly rapid roast which takes place may be due to the sulphide being in a very fine state of subdivision1 and more or less porous1 thus allowing the air ready access to the sulphur1 producing sulphurous acid gas 7,,so74 ,on the other hand1 others1 of whom ,mr4 ,carmichael is the chief exponent1 claim that several reactions take place during the operation1 connected with the rhodonite and lime compounds present in the slimes1 which he describes as follows3 8,the temperature of the kilns having reached a dull red heat1 the rhodonite 7silicate of manganese7 is converted into manganous oxide and silica2 at a rather higher temperature the calcium compounds are also split up1 with formation of calcium sulphide1 the sulphur being provided by the slimes4 ,the air permeating the mass oxidizes the manganese oxide and calcium sulphide into manganese tetroxide and calcium sulphate respectively1 as shown as follows2 #c,mn,o ,o ,mn,o ,ca,s #d,o ,ca,s,o1 and1 as such1 are carriers of a form of concentrated oxygen to the sulphide slimes1 with a corresponding reduction to manganous oxide and calcium sulphide1 as shown by the following equation1 in the case of lead3 ,pb,s #d,mn,o ,pb,s,o #ab,mn,o ,pb,s ,ca,s,o ,pb,s,o ,ca,s4 ,the oxidation of the manganous oxide and calcium sulphide is repeated1 and these alternate reactions recur until the desulphurization ceases1 or the kiln cools down to a temperature below which oxidation cannot occur4 ,these reactions1 being heat-producing1 provide part of the heat necessary for desulphurization1 which is brought about by certain concurrent reactions between metallic sulphates and sulphide4 8,the first that probably occurs is that in which two equivalents of the metallic sulphide react on one of the metallic sulphate with reduction to the metal1 metallic sulphide1 and sulphurous acid1 as shown by the following equation in the case of lead3 #b,pb,s ,pb,s,o #b,pb ,pb,s #b,,so4 8,the metal so formed1 in the presence of air1 is oxidized1 and in this state reacts on a further portion of the metallic sulphide produced1 with an increased formation of metal and evolution of sulphurous acid1 according to the following equation1 in the case of lead3 #b,pb,o ,pb,s ,pb ,,so4 8,the metal so produced in this reaction is wholly reoxidized by the oxygen of the air current1 and being free to react on still further portions of the metallic sulphide1 repeats the reaction1 and becomes an important factor in the desulphurizing of the undecomposed portion of the material4 ,as the desulphurization proceeds1 and the sulphate of metal accumulates1 reactions are set up between the metallic sulphide and different multiple proportions of the metallic sulphate1 with the formation of metal1 metallic oxide1 and evolution of sulphurous acid1 as follows3 8,with two equivalents of metallic sulphate to one equivalent of metallic sulphide1 in the case of lead1 according to the following equation3 ,pb,s #b,pb,s,o #b,pb,o ,pb #c,,so4 8,with three equivalents of metallic sulphate to one of metallic sulphide1 in the case of lead1 according to the following equation3 ,pb,s #c,pb,s,o #d,pb,o #d,,so40 ,the volatility of sulphide of lead--especially in the presence of an inert gas such as sulphurous acid--being greater than that of the sulphate1 oxide1 or the metal itself1 it might be thought that the conditions are conducive to a serious loss of lead4 ,this1 however1 is reduced to a minimum1 owing to the easily volatilized sulphide being trapped1 as non-volatile sulphate1 by small portions of sulphuric anhydride 7,,so71 which is formed by a catalytic reaction set up between the hot ore1 sulphurous acid1 and the air passing through the mass4 ,owing to the non-volatility of the silver compounds in the slimes1 the loss of this metal has been found to be inappreciable4 ,the zinc contents of the slime are reduced appreciably1 thus rendering the material more suitable for smelting4 ,after desulphurization ceases1 a few days are allowed for cooling off4 ,on the breaking up of the mass for despatch to the smelters1 as much of the lower portion of the walls is left intact as possible1 so that it can be utilized for the next roast1 thus avoiding the re-building of the whole of the walls4#aj ,,the ,,preparation ,,of ,,fine ,,material ,,for ,,smelting ,,by ,t4 ,j4 ,,greenway 7,january #ab1 #aije7 ,in the course of smelting1 at the works of the company known as the ,broken ,hill ,proprietary ,block #ad1 material which consisted chiefly of silver-lead concentrate and slime1 resulting from the concentration of the ,broken ,hill complex sulphide ore1 ,i had to contend with all the troubles which attend the treatment of large quantities of finely divided material in blast furnaces4 ,with the view of avoiding these troubles1 ,i experimented with various briquetting processes2 and1 after a number of more or less unsatisfactory experiences1 ,i adopted a procedure similar to that followed in manufacturing ordinary bricks by what is known as the semi-dry brick-pressing process4 ,this method of briquetting not only converts the finely divided material cheaply and effectively into hard semi-fused lumps1 which are especially suitable for the heavy furnace burdens required by modern smelting practice1 but also eliminates sulphur1 arsenic1 etc41 to a great extent2 therefore1 it is capable of wide application in dealing with concentrate1 slime1 and other finely divided material containing lead1 copper and the precious metals4 ,this briquetting process comprises the following series of operations3 #a4 ,mixing the finely divided material with water and newly slaked lime4 #b4 ,pressing the mixture into blocks of the size and shape of ordinary bricks4 #c4 ,stacking the briquettes in suitably covered kilns4 #d4 ,burning the briquettes1 so as to harden them1 without melting1 at the same time eliminating sulphur1 arsenic1 etc4 #a4 ,the material is dumped into a mixing plant1 together with such proportions of screened slaked lime 7usually from three to five per cent47 and water as shall produce a powdery mixture which will1 on being squeezed in the hand1 cohere into dry lumps4 ,in preparing the mixture1 it is well to mix sandy material with suitable proportions of fine1 such as slime1 in order that the finer material may act as a binding agent4 ,the mixer used by me consists of an iron trough1 about #h ft4 long1 traversed by a pair of revolving shafts1 carrying a series of knives arranged screw-fashion2 and so placed that the knives on one shaft travel through the spaces between the knives on the other shaft4 ,the various materials are dumped into one end of the mixing trough1 from barrows or trucks1 and are delivered continuously at the other end of the trough1 into an elevator which conveys the mixture to the brick-pressing plant4 #b4 ,the plant employed was the semi-dry brick-press4 ,this machine receives the mixture from the elevators1 and delivers it in the form of briquettes1 which can at once be stacked in the kilns4 ,it was found that such material as concentrate and slime has comparatively little mobility in the dies during the pressing operation2 this necessitates the use of a device which provides for the accurate filling of the dies4 ,it was also found that the materials treated by smelters vary in compressibility1 and this renders necessary the adoption of a brick-pressing plant having plungers which are forced into the dies by means of adjustable springs1 brick-presses having plungers actuated by rigid mechanism being extremely liable to jam and break4 #c4 ,briquettes made from such material as concentrate and slime vary in fusibility2 they are also combustible1 and while being burned they produce large quantities of smoke containing sulphurous acid and other objectionable fumes4 ,it is therefore necessary that such briquettes be burned in kilns provided with arrangements for accurately controlling the burning operations1 and for conveniently disposing of the smoke4 ,suitable kilns1 which will contain from #cj to #ej tons of briquettes per setting1 are employed for this purpose4 ,regenerative kilns of the ,hoffman type might be used for dealing with some classes of material1 but1 for general purposes1 the kilns as designed here will be found more convenient4 ,the briquettes are stacked according to the character of the material and the object to be obtained4 ,the various methods of stacking1 and the reasons for adopting them1 can be readily learned by studying ordinary brick-burning operations in any large brick-yard4 ,after the stacking is complete the kiln-fronts are built up with burnt briquettes produced in conducting previous operations1 and all the joints are well luted4 #d4 ,in burning briquettes made from pyrite or other self-burning material1 it is simply necessary to maintain a fire in the kiln fireplaces for a period of from #aj to #bj hours4 ,when it is judged that this firing has been continued long enough1 the fire-bars are drawn and the fronts are luted with burnt briquettes in the same manner as the kiln-fronts4 ,holes about two inches square are then made in these lutings1 through which the air required for the further burning of the briquettes is allowed to enter the kilns under proper control4 ,after the fireplaces are thus closed the progress of the burning1 which continues for periods of from three to six days1 is watched through small inspection holes made in the kiln-fronts2 and when it is seen that the burning is complete the fronts are partially torn away1 in order to accelerate the cooling of the burnt briquettes1 which are broken down and conveyed to the smelters as soon as they can be conveniently handled4 ,when briquettes made from pyrite concentrate1 or of other free-burning material1 are thus treated1 they are not only sintered but they are also more or less effectively roasted1 and it may be taken for granted that any ore which can be effectively roasted in the lump form in kilns or stalls will form briquettes that will both sinter and roast well2 indeed1 one may say more than this1 for briquettes which will sinter and roast well can be made from many classes of ore that cannot be effectively treated by ordinary kiln-and stall-roasting operations2 and1 moreover1 good-burning briquettes may be made from mixtures of free-burning and poor-burning material4 ,briquettes containing large proportions of pyrite or other free-burning material will1 unless the air-supply is properly controlled1 often heat up to such an extent as to fuse into solid masses1 much in the same manner as matte of pyritic ore will melt when it is unskilfully handled in roasting4 ,in dealing with material which will not burn freely1 such as roasted concentrate1 the briquetting is conducted with the intention of sintering the material2 and in this case the firing of the kilns is continued for periods of from three to four days1 the procedure being similar in every way to that followed in burning ordinary bricks4 ,when conducting my earlier briquetting operations ,i made the briquettes by simply pugging the finely divided material1 following a practice similar to that adopted in producing 8slop-made0 bricks by hand4 ,this method of making the briquettes was attended with a number of obvious disadvantages1 and was abandoned as soon as the semi-dry brick-pressing plant became available4 ,the extent to which this process1 or modifications of it1 may be applied is shown by the fact that1 following upon information given by me1 the ,broken ,hill ,proprietary ,company adopted a similar method of sintering and roasting slime1 consisting of about #bj per cent4 galena1 #bj per cent4 blende1 and #fj per cent4 silicious gangue4 ,the procedure followed in this case consisted of simply pugging the slime1 and running the pug upon a floor to dry2 afterward cutting the dried material into lumps by means of suitable cutting tools1 and then piling the lumps over firing foundations1 following a practice similar to that pursued in conducting ordinary heap-roasting4 ,this company is now treating from #ejj to #ajjj tons of slime weekly in this manner4 ,it is1 however1 certain that better results would attend the treatment of this material by making this slime into briquettes and burning them in kilns4 ,the cost of briquetting and burning material in the manner first described1 with labor at #be;c4 per hour1 and wood or coal at #d per ton1 amounts to from #a to #a4ej per ton of material4 ,,the ,,briquetting ,,of ,,minerals ,,by ,,robert ,,schorr 7,november #bb1 #aijb7 ,the value of briquetting in connection with metallurgical processes and the manufacture of artificial stone is well understood and appreciated4 ,in smelting plants there is always more or less flue dust1 fine ores1 and sometimes fine concentrates to be treated1 but the charging of such fine material directly into a furnace would cause trouble and irregularities1 and would lessen its capacity also4 ,as mineral briquetting cannot be effected without considerable wear upon the machinery and without quite appreciable expense in binder1 labor1 and handling1 many smelters try to avoid it4 ,the financial question1 however1 is not as serious as it may at first appear1 and taking the large output of modern briquetting machines in consideration1 the cost for repairs amounts only to a few cents per ton of briquetted material4 ,the total cost depends in the first place on the cost of labor1 power and the binder1 and in most ,american smelters it varies between #j4fe and #a4be per ton of briquettes4 ,ordinary brick presses1 with clay as a binder1 were used in ,europe as well as in this country1 but they are too slow and expensive for large propositions and the presence of clay is usually undesirable4 ,the ,english ,yeadon 7fuel7 press has also been used for some years at the ,carlton ,iron ,company's ,works at ,ferryhill in ,england1 and at the ,ore and ,fuel ,company's plant at ,coatbridge in the same country2 also by some ,continental firms4 ,dupuis ,sons1 ,paris1 furnished a few presses which are mostly used for manganese and iron ores and pyrites4 ,in some localities coke dust is added4 ,the making of clay briquettes or mud-cakes is the crudest form of briquetting2 but while heat has to be expended to evaporate the #dj to #ej per cent4 of moisture in them1 and while considerable flue dust is made1 this method is better than feeding fine ore or flue dust directly into the furnace4 ,the only other method of avoiding briquetting is by fusing ore fines in slagging reverberatory furnaces and by adding flue dust in the slagging pit1 thus incorporating it with the slagging ore4 ,this is practised sometimes in silver-lead smelters1 but in connection with copper or iron smelters it is not practicable4 ,in briquetting minerals a thorough mixing and kneading is of the first importance4 ,if this is done properly a comparatively low pressure will suffice to create a good and solid briquette1 which after six to eight hours of air-drying1 or after a speedier elimination of the surplus of moisture in hot-air chambers1 will be ready for the furnace charge4 ,a good briquette should permit transportation without excessive breakage or dust a few hours after being made1 and it should retain its shape in the furnace until completely fused1 so as to create as little flue dust as possible4 ,the briquette should be dense1 otherwise it will crumble under the influence of bad weather4 ,the two presses on the ,american machinery market are the type built by the ,chisholm1 ,boyd ,white ,company1 of ,chicago1 and the briquetting machine manufactured by the ,h4 ,s4 ,mould ,company1 of ,pittsburg4 ,both are extensively used1 and in many metallurgical plants it will pay well to adopt them4 ,from #d to #f per cent4 of milk of lime is generally used as binder1 and this has a desirable fluxing influence also4 ,a complete outfit comprises1 besides the press1 a mixer for slacking the lime1 and a feed-pump which discharges the liquid in proportion into the main mixer wherein the ore fines1 flue dust1 or concentrates are shoveled4 ,the ,chisholm1 ,boyd ,white ,company's press makes #hj briquettes per minute1 which1 with a new disk1 are of #d in4 diameter and #b in4 hight1 thus giving about #hgb cu4 ft4 of briquette volume per #aj hours1 or #ej to #hj tons1 depending on the weight of the material4 ,with the wear of the disk the hight of the briquettes is reduced and consequently the capacity of the machine also4 ,the disk weighs about #afjj lb41 and as most large smelters have their own foundries it can be replaced with little expense4 ,about #cj effective horse-power is usually provided for driving the apparatus4 ,the machine is too well known to metallurgists and engineers to require further comment or description4 ,the ,h4 ,s4 ,mould ,company has also succeeded in making its machine a thorough practical success4 ,this machine is a plunger-type press4 ,the largest press built employs six plungers1 and at #be revolutions it makes #aej briquettes of #c in4 diameter and #c in4 hight1 or #ajhj cu4 ft4 per #aj hours4 ,its rated capacity is #ajj tons per #aj hours4 ,in using a plunger-type press the material should not contain more than #g per cent4 mechanical moisture4 ,if wet concentrates have to be briquetted it is necessary to add dry ore fines or flue dust to arrive at a proper consistency4 ,the briquettes are very solid and only air-drying for a few hours is necessary4 ,the cylindrical shape of briquettes is very good1 as it insures a proper air circulation in the furnace and consequently a rapid oxidation and fusion4 ,the wear of the ,mould ,company's press is mostly confined to the chilled iron bushings and to the pistons4 ,auxiliary machinery consists of the slacker1 the feeder and the main mixer4 ,the press is of a very substantial design1 and it is claimed that the cost of repairs does not amount to more than #c;c4 per ton of briquettes4 ,wear and tear is unavoidable in a crude operation like briquetting2 to treat flue dust1 ore fines1 and fine concentrates successfully1 it is almost absolutely necessary to resort to it4 ,edison used a number of intermittent-acting presses at his magnetic iron-separation works in ,new ,jersey1 but this plant shut down some time ago4 ,a ,,bricking ,,plant ,,for ,,flue ,,dust ,,and ,,fine ,,ores ,,by ,,james ,c4 ,,bennett 7,september #ae1 #aijd7 ,the plant1 which is here described1 for bricking fine ores and flue dust1 was designed and the plans produced in the engineering department of the ,selby smelter4 ,the machinery contained in the plant consists of a ,boyd four-mold brick press1 a #g ft4 wet pan or ,chile mill1 a #ej h4p4 induction motor1 and a conveyor-elevator1 together with the necessary pulleys and shafting4 ,the press1 ,chile mill1 and motor need no special mention1 as they all are from standard patterns and bought1 without alterations1 from the respective builders4 ,the ,chile mill was purchased from the builders of the brick press4 ,the conveyor-elevator was built on the premises and consists of a #ad in4 eight-ply rubber belt1 with buckets of sheet steel placed at intervals of #f in41 running over flanged pulleys4 ,the buckets1 or more properly speaking the flights1 are made from ,no4 #ab steel plate1 flanged to produce the back and ends1 with the ends secured to the flanged bottom by one rivet in each4 ,the plant has been in operation for sixteen months and there have been few or no repairs to the elevator1 except to renew the belt1 which is attacked by the acid contained in the charges4 ,this first belt was in continuous use for nine months4 ,as originally designed1 the capacity was #ajj tons per day of #ab hours1 but this was found to require a speed so high that the workmen were unable to handle the output of the press4 ,the speed was1 consequently1 reduced about #be per cent41 which brings the output down to about #ge tons per day4 ,this output1 as expressed in weight1 naturally varies somewhat owing to the variation in the weight of the material handled4 ,it is probable that the capacity could be increased to about #ij tons by enlarging the bricks1 which could be done1 but would require a considerable amount of alteration in the machine1 as it is designed to produce a standard sized building brick4 ,by this method of increase1 however1 the work of handling would not be materially increased1 because the number of bricks would be the same as with the present output of #ge tons2 there would be about #af per cent4 more to handle1 by weight4 ,working on the basis of #ajj tons capacity1 the bins were designed to afford storage room for about three days' run1 or a little over #cjj tons4 ,the bins are made entirely of steel1 in order that the hot material may be dumped into them directly from the roasting furnaces1 thus saving one handling4 ,in order that there may be room for several kinds of material1 the bins are divided into seven compartments1 three on one side and four on the other4 ,the lower part is of in4 steel plate1 and the upper1 about one-half the hight1 of #e_/af in4 plate4 ,it may be well to call attention to the method of handling the material1 preparatory to its delivery to the brick press4 ,the bins are constructed1 as will be seen by the drawing1 with their floor set #b4e ft4 above the working floor1 which enables the workmen to reach the material with a minimum effort4 ,the floor of the bins project #b4e ft4 in front of the face1 thus forming a platform on which the shoveling may be done without the necessity of bending over4 ,in this projecting platform are cut rectangular holes #ab #ah in41 which are placed midway between the openings in the front of the bins and furnished with screens to stop any stray bolts or other coarse material that might injure the press4 ,this position of the holes through the platform was adopted so that1 in the event of the material running out beyond the opening in the face1 it would not fall directly upon the floor4 ,two buckets are provided1 with a capacity of #g cu4 ft4 each1 which is the size of a single charge of the ,chile mill4 ,these buckets have a hopper-shaped bottom fixed with a swinging gate which is operated by the foot2 thus the bucket can be run over the pan of the ,chile mill and the charge dumped directly into it4 ,the buckets run on an overhead iron track 7#a in4 by #c in47 hung #g ft4 in the clear1 above the floor4 ,the method of making up the charge is as follows3 ,the bucket is run under the hole in the platform nearest to the compartment containing the material of which the charge is partly composed1 and a predetermined number of shovelfuls is drawn out and put into the bucket1 which is then pushed on to the next compartment from which material is wanted1 where the operation is repeated4 ,after charging into the bucket the requisite amount of ore or flue dust1 the bucket is run to the back of the building1 where the necessary amount of lime 7slaked7 is added4 ,by putting the lime in last1 it is so surrounded by the dust or ore that it has not the opportunity to stick to the sides of the bucket in discharging1 as it otherwise would4 ,illustration3 ,,fig4 #a 7a74--,plant for ,bricking ,ores1 ,selby ,smelter4 7,plan47 ,the number of men required to operate the entire plant1 exclusive of those employed in bringing the material to the bins and emptying the cars into them1 is #ab1 placed as follows2 ,one preparing the lime for use1 one removing the charge from the mill and supplying the elevator-conveyor1 which is accomplished by means of a specially shaped1 long-handled shovel2 one keeping the supply spout of the press clear 7an attempt was made to do this mechanically1 but was found to be unsuccessful1 owing to the extremely sticky nature of the material1 and so was discarded in favor of manual labor72 one to control the press in case of mishap and to keep the dies clean2 one oiler2 three receiving the bricks from the press and taking the brick-loaded cars from the press to the drying-house1 and two placing the bricks on the shelves4 ,illustration3 ,,fig4 #a 7b74--,plant for ,bricking ,ores1 ,selby ,smelter4 7,elevation47 ,the drying-house scarcely requires description2 it is but a roofed shed1 without sides1 fitted with stalls into which the bricks are set on portable shelves1 as close as working conditions will permit4 ,the means of drying1 at the present time1 is by the natural circulation of air1 but a mechanical system is in contemplation1 by which the air will be drawn into the building from the outside and forced to find its way out through the bricks4 ,the drying-house is adjacent to the pressing plant1 in fact forms the back of it1 so that there is a minimum distance to haul the product4 ,the time required for drying the bricks sufficiently for them to withstand the necessary handling is1 depending on the weather1 from two to eight days1 the usual time being about three days4 ,,part ,,iv ,,smelting ,,in ,,the ,,blast ,,furnace ,,modern ,,silver-,,lead ,,smelting#aa ,,by ,,arthur ,s4 ,,dwight 7,january #aj1 #aijc7 ,the rectangular silver-lead blast furnace developed in the ,rocky ,mountains has an area of #db #abj to #dh #afj in4 at the tuyeres2 #ed #acb to #hd #bjj in4 at the top2 and hight from tuyere level to top of charge of #ae to #ba ft4 ,such a furnace smelts #hj to #bjj tons of charge 7ore and flux1 but not slag and coke7 per #bd hours4 ,the slag that has to be resmelted amounts to #bj to #fj per cent4 of the charge4 ,coke consumption is #ab to #af per cent4 of the charge4 ,the blast pressure ranges from #a4e to #d lb4 per square inch1 averaging close to #b lb4 ,gases of hand-charged furnaces are taken off through an opening below the charge-floor1 the furnace being fed through a slot 7about #bj in4 wide1 extending nearly the whole length of the furnace7 in the iron floor-plates2 or through a hood 7brick or sheet iron7 above the charge-floor level1 with a down-take to the flues1 charge-doors being provided on each side of the hood1 extending preferably the whole length of the furnace and usually having a sill a few inches high which compels the feeder to lift his shovel4 ,when a silver-lead blast furnace is operating satisfactorily1 the following conditions should obtain2 7#a7 ,a large proportion of the lead in the charge should appear as direct bullion-product at the lead-well4 7#b7 ,the slag should be fluid and clean4 7#c7 ,the matte should be low in lead4 7#d7 ,the furnace should be cool and quiet on top1 making a minimum quantity of lead-fume and flue-dust1 and the charges should descend uniformly over the whole area of the shaft4 7#e7 ,the furnace speed should be good4 7#f7 ,the furnace should be free from serious accretions and crusts2 that is to say1 the tuyeres should be reasonably bright and open1 and the level of the lead in the lead-well should respond promptly to variations of pressure1 caused by the blast and by the hight of the column of molten slag and matte inside the furnace--an indication that ample connection exists between the smelting column and the crucible4 ,good reduction 7using that term to express the degree in which the furnace is manifesting its reducing action7 is obtained when the first three of the above conditions are satisfied4 ,for any given furnace there are five prime factors1 the resultant of which determines the reduction1 namely3 7a7 ,chemical composition of the furnace charges2 7b7 proportion and character of fuel2 7c7 air-volume and pressure1 to which might perhaps also be added temperature of blast2 for1 although hot blast has not yet been successfully applied in lead-smelting practice1 ,i believe it is only a question of time when it will be2 7d7 dimensions and proportions of smelting furnace2 7e7 mechanical character and arrangement of the smelting column4 ,all but one of the above factors can be intelligently gaged4 ,the mechanical factor1 however1 can be expressed only in generalities and indefinite terms4 ,a wise selection of ores and proper preliminary preparation1 crushing the coarse and briquetting the fine1 will do much to regulate it1 but all this care may be largely nullified by careless feeding4 ,the importance and possibilities of the mechanical factor are generally overlooked and its symptoms are wrongly diagnosed4 ,for instance1 the importance of slag-types has undoubtedly been considerably exaggerated at the expense of the mechanical factor4 ,slags seldom come down exactly as figured4 ,we must know our ores and apply certain empirical corrections to the iron1 sulphur1 etc41 based on previous experience with the ores2 but these empirical corrections may represent also an unformulated expression of the influence of the mechanical factor on the reduction--a function1 therefore1 of the ruling physical complexion of the ores1 and the peculiarities of the feeding habitually maintained in the works concerned4 ,with a given ore-charge large reciprocal variations may be produced in the composition of slag and matte by merely changing the mechanical conditions of the smelting column1 and since the efficient utilization of both fuel and blast must be controlled in the same way1 the mechanical factor may be considered1 perhaps1 the dominating agent of reduction4 ,inasmuch as there is no way of gaging it1 however1 the only recourse is to seek a correct adjustment and maintain it as a positive constant1 after which slag1 fuel and blast may be with much greater certainty adjusted toward efficiency of furnace work and metal-saving4 ,behavior of ,iron4--,the output of lead is so dependent upon the reactions of the iron in the charge that the chief attention may well be fixed upon that metal as the key to the situation4 ,the success of the process depends largely upon reducing just the right amount of iron to throw the lead out of the matte1 the remainder of the iron being reduced only to ferrous oxide and entering the slag4 ,too much iron reduced will form a sow in the hearth4 ,iron is reduced from its oxides principally by contact with solid incandescent carbon1 and by the action of hot carbon monoxide4 ,reduction by solid carbon is the more wasteful1 but there is in lead smelting an even more serious objection to permitting the reduction to be accomplished by that means1 which leads to comparatively hot top and more or less volatilization of lead4 ,reduction by carbon monoxide is the ideal condition for the lead furnace4 ,it means keeping the zone of incandescence low in the charge column1 leaving plenty of room above for the gases to yield up their heat to1 and exercise their reducing power on1 the descending charge1 so that by the time they escape they will be well-nigh spent4 ,their volume and temperature will be diminished1 and the low velocity of their exit will tend to minimize the loss of lead in fume and flue dust4 ,the idea that high temperatures in lead blast furnaces should be avoided is based on a misconception4 ,temperatures must exist which are sufficiently high to volatilize all the lead in the charge1 if other conditions permit4 ,a high temperature before the tuyeres means fast smelting2 and fast smelting1 under proper conditions1 means a shortening of the time during which the lead is subject to scorifying and volatilizing influences4 ,a rapidly descending charge1 constantly replenished with cold ore from above1 absorbs effectively the heat of the gases and acts as a most efficient dust and fume collector4 ,in considering long flues1 bag-houses1 etc41 it should be kept in mind that the most effective dust collector ought to be the furnace itself4 ,in the practice of twelve years ago and earlier1 particularly when using mixed coke and charcoal1 reduction by carbon was probably the rule2 and the percentage of fuel required was very high4 ,there is good reason to think we have still much room for improvement along this line in our average practice of today4 ,volume of ,blast4--,it is customary to supply a battery of furnaces from a large blast main1 connected with a number of blowers4 ,inasmuch as the air will take preferably the line of least resistance1 if the internal resistance of any one furnace be increased the volume of air it will take will be diminished and the others will be favored unduly4 ,only by keeping all the furnaces on approximately the same charge1 with the same hight of smelting column1 can anything like uniformity of operation and close regulation be secured4 ,the rational plan would seem to be to have a separate blower1 of variable speed1 directly connected to each furnace1 but this plan1 which has had a number of trials1 has usually been abandoned in favor of the common blast main4 ,trials by myself1 extending over considerable periods1 have been so uniformly favorable1 however1 that ,i am forced to ascribe the failure of others to some outside reason4 ,the peculiar atmosphere required in the lead blast furnace depends upon the correct proportion of two counteractive elements1 carbon and oxygen4 ,if given too much air the furnace will show signs of deficient reduction1 commonly interpreted as calling for more fuel1 which will be sheer waste since its object is to burn up surplus air4 ,there will be an additional waste through the extra coal burned under the steam boilers4 ,the true remedy would be to cut down the quantity of air4 ,burning up excessive coke is as hard work as smelting ore4 ,too much fuel invariably slows up a furnace2 it also drives the fire upward and gives predominance to reduction by solid carbon4 ,the maintenance of a minimum fuel percentage1 with a correctly adjusted volume of air1 will tend to promote the conditions under which iron will be reduced by the gases1 rather than by solid carbon4 ,pressure of ,blast4--,pressure necessarily involves resistance2 and the blast-pressure1 as registered by a simple mercury-gage on the bustle-pipe1 may be increased in two ways3 7#a7 ,by increasing the volume of air forced through the interstices in the charge4 ,this is the wrong way2 but1 unfortunately1 it is only too common in our practice1 and therefore deserves to be mentioned1 if only to be condemned4 7#b7 ,by leaving the volume of air unchanged1 but increasing the friction offered by the interstitial channels1 either by making them smaller in aggregate cross-section 7which means a finer charge71 or by making them longer 7which means a higher smelting column74 ,a correctly graduated internal resistance is1 therefore1 the only true basis for a high blast furnace1 which1 when so produced1 will bring about rapid smelting1 a low zone of incandescence1 and a very vigorous action upon the ores by the gases in their retarded ascent through the charge column4 ,these conditions promote the reduction of iron by ,,co4 ,the adjustment of internal resistance1 which is thus clearly the main factor1 can be accomplished only by the correct feeding of the furnace4 ,feeding the ,charge4--,it is self-evident that1 the more thorough the preliminary preparation of the charge before it reaches the zone of fusion1 the more rapidly can the actual smelting proceed4 ,a piece of raw ore that finds itself prematurely at the tuyeres1 without having been subjected to the usual preparatory processes of drying1 heating1 reduction1 etc41 must remain there until it is gradually dissolved or carried away mechanically in the slag4 ,any such occurrence must greatly retard the process4 ,it would seem1 by the same reasoning1 that an intimate mixture of the ingredients of the charge should expedite the smelting1 and ,i advocate the intimate mixture of the charge ingredients in all cases4 ,the theory of feeding is simple1 but not so the practice4 ,if the charge column were composed of pieces of uniform size1 the ascending gases would find the channel of least resistance close to the furnace walls and would take it preferably to the center of the shaft4 ,the more restricted channel would necessitate a higher velocity1 so that not only would the center of the charge be deprived of the action of the gases1 but also the portion traversed would be overheated2 many particles of ore would be sintered to the walls or carried off as flue dust2 slag would form prematurely2 fuel would be wasted2 in short1 all the irregularities and losses which accompany over-fire would be experienced4 ,in practice the charge is never uniform1 but is a mixture of coarse and fine4 ,by lodging the finer material close to the walls and placing the coarser in the center1 an adjustment may be made which will cause the gases to ascend uniformly through the smelting column4 ,a furnace top smoking quietly and uniformly over its whole area is the visible sign of a properly fed furnace4 ,effect of ,large ,charges4--,it has frequently been remarked that1 within certain limits1 large charges give more favorable results than small ones2 and numerous attempts have been made to account for this fact4 ,my observations lead me to offer the following as a rational explanation--at least in cases where ore and fuel are charged in alternate layers4 ,large ore-charges mean correspondingly large fuel-charges4 ,the gases can pass readily through the coke2 and hence each fuel-zone tends to equalize the gas currents by giving them another opportunity to distribute themselves over the whole furnace area1 while each layer of ore subsequently encountered will blanket the gases1 and compel them to force a passage under pressure1 which is the manner most favorable to effective chemical action4 ,in mechanically fed furnaces the charges of ore and fuel are usually dropped in simultaneously from a car and the separate layers thus obliterated1 and the distributing zones which are such a safeguard against the consequences of bad feeding are lacking1 hence more care must be exercised to secure proper placing of the coarse and fine material4 ,this may throw some light on the failure of most of the early attempts at mechanical feeding4 ,mechanical ,character of ,charge4--,very fine charges blanket the gases excessively and cause them to break through at a few points1 forming blow-holes1 which seriously disturb the operation1 cause loss of raw ore in the slag1 and are accompanied by all the evils of over-fire4 ,a charge containing a few massive pieces1 the rest being fine1 is a still more unfavorable combination4 ,a very coarse charge permits too ready an exit to the gases1 and in the end tends likewise to over-fire and poor reduction4 ,the remedy is to briquette the fine ore 7though preferably not all of it71 and crush the coarse to such degree as to approach an ideal result1 which may be roughly described as a mixture in which about one-third is composed of pieces of #e to #b in4 in diameter1 one-third pieces of #b to #j4e in41 and the remaining third from #j4e in4 down4 ,the coke is better for being somewhat broken up before charging1 and a reasonable amount of coke fines1 such as usually accompanies a good quality of coke1 is not in the least detrimental4 ,the common practice of handling the coke by forks and throwing away the fines is to be condemned as an unwarranted waste of good fuel4 ,the slag on the charge should be broken to pieces at most #f in4 in diameter4 ,the common practice of throwing in whole butts of slag-shells is bad4 ,there is no economy in using the slag hot2 cold charges1 not hot1 are what we want4 ,a reasonable amount of moisture in the charge is beneficial1 providing it be in such form as to be readily dried out4 ,it is often advantageous to wet the ore mixtures while bedding them1 or to sprinkle the charges before feeding4 ,the driving off of this water must consume fuel1 but not so much as if the smelting zone crept up4 ,large doses of water applied directly to the furnace are unpardonable under any circumstances1 however1 though they are sometimes indulged in as a drastic measure to subdue excessive over-fire when other and surer means are not recognized4 ,one of the chief merits of moderate sprinkling before charging is that it gives in many cases a more favorable mechanical character1 approximating a lumpy condition in too fine a charge1 and assisting to pack a too coarse one4 ,different ,behavior of ,coarse and ,fine ,ore4--,in taking up a shovelful of ore1 the fine will be observed to predominate in the bottom and center1 and the coarse on the top and sides4 ,when thrown from the shovel1 the coarse will outstrip the fine and fall beyond it4 ,in making a conical pile the coarse ore will roll to the base1 leaving the fine near the apex4 ,this difference in the action of the mobile coarse ore and the sluggish fines is the key to the practical side of feeding1 both manual and mechanical4 ,it is not sufficient to tell the feeder to throw the coarse in the middle and the fine against the sides2 if it be easier to do it some other way such instructions will count for little4 ,the desired result can be best secured by making the right way easier than the wrong way4 ,it is generally conceded that the open-top furnaces1 fed by hand through a slot in the floor-plates1 do not give as satisfactory results as the hooded furnaces with long feed-doors on both sides4 ,in the open-top furnace it is comparatively difficult to throw to the sides2 the narrower the slot the greater the difficulty4 ,the major part of the charge will drop near the center1 making that place higher than the sides4 ,the fine ore will tend to stay where it falls1 while the coarse will tend to roll to the sides1 thus leading to an arrangement of the charge just the reverse of what it ought to be4 ,in the hooded furnace most of the material will naturally fall near the doors1 causing the sides to be higher than the center toward which the coarse will roll1 while the force of the throw as the ore is shoveled in will also have a tendency to concentrate the coarse material in the center4 ,once a proper balance of conditions has been found1 absolute regularity of routine is the secret of good results4 ,an experienced and intelligent feeder owes his merit to his conscientious regularity of work4 ,he may have to vary his program somewhat when he encounters a furnace that is suffering from the results of bad feeding by a predecessor2 but his guiding principle is first to restore regularity1 and then maintain it4 ,a poor feeder can bring about1 in a single shift1 disorders that will require many days to correct1 if indeed they are corrected at all during the campaign4 ,the personal element is productive of more harm than good4 ,mechanical ,feeding4--,if it be admitted that the work of a feeder is the better the more it approximates the regularity of that of a machine1 it ought to be desirable to eliminate the personal factor entirely and design a machine for the purpose1 which would be a comparatively simple matter if it be known just what we want to accomplish4 ,no valid ground now exists for prejudice against mechanical feeding in lead smelting4 ,it is in successful operation in a number of large works1 and is being installed in others4 ,our furnaces have outgrown the shovel2 we have passed the limit of efficiency of the old methods of handling material for them4 ,we must come to mechanical feeding in spite of ourselves4 ,but whatever may be the motive leading to its introduction1 its chief justification will be discovered1 after it has been successfully installed and correctly adjusted1 in the consequent great improvement of general operating results1 metal saving1 etc4 ,it will remove one of the most uncertain factors with which the metallurgist has to deal1 thereby bringing into clearer view for study and regulation the other factors 7fuel and blast proportion1 slag composition1 etc47 in a way that has hardly been possible under the irregularities consequent upon hand feeding4 ,,mechanical ,,feeding ,,of ,,silver-,,lead ,,blast ,,furnaces#ab ,,by ,,arthur ,s4 ,,dwight 7,january #ag1 #aijc7 ,historical4--,a silver-lead furnace fed by means of cup and cone was in operation in #ahhh at the works of the ,st4 ,louis ,smelting and ,refining ,company at ,st4 ,louis1 ,mo41 but it is probable that previous attempts had been made1 since ,hahn refers 78,mineral ,resources of the ,united ,states10 #ahhc7 in a general way to experiments with this device1 which were unsuccessful because the heat crept up in the furnace and gave over-fire4 ,at the time of my visit to the ,st4 ,louis works 7in #ahhh7 the furnaces were showing signs of over-fire1 but this may not have been their characteristic condition4 ,a4 ,f4 ,schneider1 who built the ,st4 ,louis furnaces1 afterward erected1 at the ,guggenheim works at ,perth ,amboy1 ,n4 ,j4 1 round furnaces with cup and cone feeders1 but although good results are said to have been obtained1 the running of refinery products is no criterion of what they would do on general ore smelting4 ,cup and ,cone ,feeders4--,the cup and cone is an entirely rational device for feeding a round furnace1 but is quite unsuitable for feeding a rectangular one4 ,furnaces of the latter type were installed for copper smelting at ,aguas ,calientes1 ,mex41 with two sets of circular cup and cone feeders1 but disastrous results followed the application of this device to lead furnaces4 ,the reason is clear when it is considered that a circular distribution cannot possibly conform to the requirements of a rectangular furnace4 ,a more rational device was designed for the works at ,perth ,amboy1 ,n4 ,j4 ,illustration3 ,,fig4 #b4--,perth ,amboy1 ,n4 ,j4 1 ,lead ,furnace4 ,vertical section at right angles to ,fig4 #c4 ,pfort ,curtain4--,about ten years ago some of the ,american smelters adopted the ,pfort curtain1 which1 as adapted to their requirements1 consisted of a thimble of sheet iron hung from the iron deck plates so as to leave about #ae in4 of space between it and the furnace walls1 this space being connected with the down-take of the furnace4 ,the thimble was kept full of ore up to the charge-floor4 ,this device was popular for a time1 chiefly because it prevented the furnace from smoking and diminished the labor of feeding1 but it was found to give bad results in the furnaces1 it being impossible to observe how the charge sunk 7except by dropping it below the thimble71 while the curtain had to be removed in order to bar down accretions1 and1 most important1 it caused irregular furnace work and high metal losses1 because it effected a distribution of the coarse and fine material which was the reverse of correct1 the evil being emphasized by the taking off of the gases close to the furnace walls4 ,illustration3 ,,fig4 #c4--,perth ,amboy1 ,n4,j41 ,lead ,furnace4 ,vertical section at right angles to ,fig4 #b4 ,terhune ,gratings4--,r4 ,h4 ,terhune designed a device 7,united ,states patent ,no4 #ehe1big1 ,june #bi1 #ahig71 which comprised two grizzlies1 one on each side of the furnace1 sloping downward from the edge of the charge-floor toward the center line of the furnace4 ,the bars tapered toward the center of the furnace1 the open spaces tapering correspondingly toward the sides1 so that as the charge was dumped on them a classification of coarse and fine would be effected4 ,this device is correct in conception4 ,pueblo ,system4--,in the remodeling of the plant of the ,pueblo ,smelting and ,refining ,company in #ahie1 under the direction of ,w4 ,w4 ,allen1 mechanical feeding was introduced1 and the system was the first one to be applied successfully on a large scale4 ,the furnaces of this plant are #fj #abj in4 at the tuyeres1 with six tuyeres1 #d in4 in diameter on each side1 the nozzles 7water cooled7 projecting #f in4 inside the jackets4 ,the hight of the smelting column above the tuyeres is #bj ft4 ,the gases are taken off below the charge-floor1 and the furnace tops are closed by hinged and counter-weighted doors of heavy sheet iron1 opened by the attendant1 just previous to dumping the charge-car4 ,in the side walls of the shaft are iron door-frames1 ordinarily bricked up1 but giving access to the shaft for repairs or barring out without interfering with the movement of the charge-car4 ,extending across the shaft1 about #ah in4 above the normal stock line1 are three ,a-shaped cast-iron deflectors1 dividing the area of the shaft into four equal rectangles4 ,the general arrangement of the plant is shown in ,fig4 #d4 ,from the charge-car pit there extends an inclined trestle1 on an angle of #ag deg4 to the charge-floor level1 in line with the battery of furnaces4 ,the gage of the track is approximately equal to the length of the furnaces at the top4 ,the charge-car1 actuated by a steel tail-rope1 moves sideways on this track from the charging-pit to any furnace in the battery4 ,the hoisting drums are located at the crest of the incline1 inside of the furnace building4 ,at the far end of the latter there is a tightener sheave1 with a weight to keep proper tension on the tail-rope4 ,the charge-car has a capacity of #e tons4 ,it has an ,a-shape bottom1 and is so arranged that one attendant can quickly trip the bolt and discharge the car4 ,illustration3 ,,fig4 #d4--,pueblo ,system4 ,longitudinal vertical section through incline4 ,while the car is making its trip the charge-wheelers are filling their buggies1 working in pairs1 each man weighing up a halfcharge of a particular ingredient4 ,they then separate1 each taking his proper place in the line of wheelers on either side4 ,when the car has returned1 the wheelers successively discharge their buggies into opposite ends of the car4 ,the coke is added last1 to avoid crushing4 ,the system is not strictly economical of labor1 since the wheelers1 who must always be ready for their car1 have to wait for its return1 which necessitates more wheelers than would otherwise be required4 ,figs4 #e1 #f and #g show the car4 ,illustration3 ,,fig4 #e4--,pueblo ,charge-car4 7,side elevation47 ,a vertical section through the car filled by dumping from the two ends will show an arrangement of coarse and fine1 which is far from regular4 ,analyzing its structure1 we shall find a conical pile near each end1 with a valley between them1 in which coarse ore will predominate4 ,the deflectors in the furnace1 previously referred to1 serve to scatter the fines as the charge is dropped in4 ,without them the feeding of the furnace would be a failure2 with them it is successful1 though not so completely as might be1 the furnaces having a tendency to run with hot tops4 ,with the battery of seven furnaces1 each smelting an average of #ajj tons of ore per day1 the saving1 as compared with hand-feeding1 was #fc per day1 or #i;c4 per ton of ore1 this including cost of steam1 but not wear and tear on the machinery4 ,this is distinctly a maximum figure2 with fewer furnaces the fixed charges of the mechanical feed would soon increase the cost per ton to such a figure that the two systems would be about equal in economy4 ,illustration3 ,,fig4 #f4--,pueblo ,charge-car4 7,plan47 ,illustration3 ,,fig4 #g4--,pueblo ,charge-car4 7,end elevation47 ,east ,helena ,system4--,this was introduced at the ,east ,helena plant of the ,united ,smelting and ,refining ,company by ,h4 ,w4 ,hixon4 ,the plant comprised four lead furnaces1 each #dh #acf in41 with a #ba ft4 smelting column4 ,they were all open-top furnaces1 fed through a slot over the center1 the gases being taken off below the floor4 ,they were capable of smelting about #ahj tons of charge 7ore and flux7 per #bd hours1 using a blast of #cj to #dh oz41 furnished by two ,allis duplex1 horizontal1 piston blowers1 air-cylinders #cf in4 diam41 #db in4 stroke1 belted from electric motors4 ,the ,hixon feed was designed to meet existing conditions1 without irrevocably cutting off convenient return to hand feeding in case of an emergency4 ,as shown in ,fig4 #i there is a track-way at right angles to the line of furnaces4 ,the car hoisted up the incline is landed on a transfer carriage1 on which1 after detaching the cable1 it can be moved over the tops of the furnaces by means of a tail-rope system4 ,the gage of the charge-car is #d ft4 #i in42 of the transfer carriage1 #aa ft4 #h in4 ,a switch at the lower end of the incline permits two charge-cars to be employed1 one being filled while the other is making the trip4 ,in sending down the empty car a hand winch is necessary to start it from the transfer carriage4 ,figs4 #aj and #aa show the charge-car2 ,fig4 #ab the transfer carriage4 ,illustration3 ,,fig4 #h4--,pueblo ,system4 7,sectional diagrams of furnace top47 ,the charge-car is #aj #d #c4e ft41 and has capacity for #f tons of ore1 flux1 slag and fuel1 the total of ore and flux being usually #hhjj lb4 ,its bottom is flat1 consisting of two doors1 hinged along the sides and kept closed by means of chains wound about a longitudinal windlass on top of the car4 ,the charging pits are decked with iron plates1 leaving a slot along the center of each car exactly like the slot in the furnace top4 ,the loaded ore-buggies are taken from the wheelers by two men1 who carefully distribute the contents of each buggy along the whole length of the charge-car by dragging it along the slot while in the act of dumping4 ,each buggy contains but one ingredient2 they follow one another in a prescribed order1 so as to secure thin layers in the charge-car4 ,the coke is divided into three or more layers4 ,illustration3 ,,fig4 #i4--;,east ,helena ,system4 7,vert-longitudinal section and plan of incline47 ,illustration3 ,,fig4 #aj4--;,east ,helena ,charge-car4 7,side elevation47 ,the first few trials of this device were not satisfactory4 ,the furnaces quickly showed over-fire1 and decreased lead output1 which would not yield to any remedy except a return to hand feeding4 ,the total charge being dropped in the center of the furnace1 a central core of fines was produced1 the lumps tending to roll toward the walls4 ,this wrong tendency was emphasized by the presence of the chains supporting the bottom of the charge-car4 ,on unwinding them to dump the car1 the doors were prevented from dropping by the wedging of the chains in the charge1 which in turn arched itself more or less against the sides of the car2 hence the doors opened but slowly1 and often had to be assisted by an attendant with a bar4 ,in consequence of this slow opening1 considerable fine ore sifted out first and formed a ridge in the center of the furnace1 from the slopes of which the coarser part of the charge1 the last to fall1 naturally rolled toward the sides4 ,this fact1 determined during a visit of the writer in ,april1 #ahii1 proved to be the key to the situation4 ,the attendant operating the tail-rope mechanism was instructed to move the transfer carriage rapidly backward and forward over the slot while the first one-third or one-half of the charge was dropping1 and during the rest of the discharge to let the car stand directly over the slot and permit the coarser material to fall in the center of the furnace4 ,two piles of comparatively fine material were thus left on the charge-floor1 one on each side of the slot4 ,these were subsequently fed in by hand1 with instructions to throw the material well to the sides of the furnace4 ,illustration3 ,,fig4 #aa4--;,east ,helena ,charge-car4 7,plan47 ,the furnaces were running very hot on top when this modified procedure was begun4 ,in a few hours the over-fire had disappeared2 the lead output was increasing2 and the furnaces were running normally4 ,this was done about ,may #a1 #ahii1 and from that time until about ,february #bj1 #aijj1 the ,hixon feed1 as modified above1 was continuously in operation4 ,in ,october1 #ahih1 with three furnaces in operation and hand feeding1 the labor cost per furnace was #db4jf per day2 in ,october1 #ahii1 with the same number of furnaces and mechanical feeding1 it was #da per day1 the saving being only #j4f;c4 per ton of charge4 ,illustration3 ,,fig4 #ab4--;,east ,helena ,charge-car and ,transfer ,carriage4 7,elevation47 ,illustration3 ,,fig4 #ac4--;,east ,helena ,system1 with spreader and curtains4 7,experimental form47 ,dwight ,spreader and ,curtain4--,in ,january1 #aijj1 the writer again had occasion to visit the ,east ,helena plant1 to investigate why a certain cheap local coke could not be used successfully instead of expensive ,eastern coke4 ,strange as it may seem1 the peculiar behavior of the cokes was traced to improper feeding of the furnaces4 ,further study of the mechanical feeding system1 then in operation for nine months1 showed that it was far from perfect1 and it appeared desirable to design a spreader which would properly distribute the material discharged from the ,hixon car and dispense with hand feeding entirely4 ,an experimental construction was arranged1 as shown in ,fig4 #ac4 ,the flanged cast-iron plates around the feeding slot were pushed back and a roof-shaped spreader1 with slopes of #de deg41 was set in the gap1 leaving openings about #h in4 wide on each side4 ,the plan provided for two iron curtains to be hung1 one on each side of the spreader1 and so adjusted that the fine ore sliding down the spreader would clear the edge of the curtain and shoot toward the sides of the furnace1 while the coarse ore would strike the curtain and rebound toward the center of the furnace4 ,the classification effected in this manner was capable of adjustment by raising or lowering the curtain4 ,this arrangement was found to work surprisingly well4 ,the first furnace equipped with it immediately showed improvement4 ,it averaged better in speed1 with lower blast1 lower lead in slag and matte1 and better bullion output than the other furnaces operating under the old system4 ,the success of the spreader and curtain being established1 the furnaces were provided with permanent constructions1 the only modifications being that the ridge of the spreader was lowered to correspond with the level of the floor and the curtains were omitted1 the feeding being apparently satisfactory without their aid4 ,in their absence1 the lowering of the spreader was a proper step1 as it distributed the material fully as well1 and caused less abrasion of the walls4 ,the final form is shown approximately in ,fig4 #ad4 ,it has given complete satisfaction at ,east ,helena since ,february1 #aijj1 and has been adopted as the basis for the mechanical feeding device in the new plant of the ,american ,smelting and ,refining ,company at ,salt ,lake1 ,utah4 ,illustration3 ,,fig4 #ad4--;,east ,helena ,system4 7,final form1 approximate47 ,comparison of ,systems4--,in mechanical design the ,pueblo system is better than the ,east ,helena1 being simpler in construction and operation4 ,no time is lost in attaching and changing cables1 operating transfer carriage1 etc4 ,in both systems the track runs directly over the tops of the furnaces1 and this is an inconvenience when furnace repairs are under way4 ,the ,pueblo car is the simpler1 and makes the round trip in about half the time of a car at ,east ,helena1 so the two cars of the latter do not make much difference in this respect4 ,the system of filling the charge-car at ,pueblo is also the quicker4 ,it may be estimated roughly that per ton of capacity it takes #b4e to #c times as long to fill the ,east ,helena car2 and this means longer waiting on the part of the wheelers1 and consequently greater cost of moving the material1 representing probably #g or #h;c41 in favor of ,pueblo1 per ton of charge handled4 ,however1 both systems are wasteful of labor4 ,as to furnace results1 it is believed that the better distribution of the charge in the ,east ,helena system leads to greatly increased regularity of furnace running1 less tendency to over-fire1 some economy in fuel1 less accretions on the furnace walls and larger metal savings4 ,if the half of these conclusions are true1 the difference of #g or #h;c4 per ton in favor of the ,pueblo system1 which can be traced almost entirely to the cost of filling the charge-car1 sinks into insignificance in comparison with the important advantages of having the furnaces uniformly and correctly fed4 ,true ,function of the ,charge-,car4--,the radically essential feature of a mechanical feeding device is that part which automatically distributes the material in the furnace1 whatever approximate means may have been used to effect the delivery4 ,taking a hasty review of the numerous feeding devices that have been tried in lead-smelting practice1 we cannot but remark the fact that those which depended upon dumping the charge into the furnace from small buggies or barrows failed generally to secure a proper classification and distribution of coarse and fine1 and1 consequently1 were abandoned as unsuccessful1 while the adoption of the idea of the charge-car for transporting the material to the furnace in large units seems to have been coincident with a successful outcome4 ,it is natural enough1 therefore1 that the car should be regarded by many as the vital feature4 ,this view of the question is not1 however1 in accordance with the true perspective of the facts1 and merely limits the field of application in an entirely unnecessary way4 ,it must be apparent that the essential function of the charge-car is cheap and convenient transportation4 ,the distribution of the charge is an entirely different matter1 in which1 however1 the charge-car may be made to assist1 as in the ,pueblo system2 or entirely distinct and special means may be employed for the distribution1 as in the ,east ,helena system4 ,to follow the argument to its conclusion1 let us imagine for the moment that the ,east ,helena plant were arranged on the terrace system1 with the furnace tops on a level with the floor of the ore-bins4 ,certain precautions being observed1 the spreader would give as good results with small units of charge delivered by buggies as it now does with the large units delivered by the charge-car1 and the expense of delivery to the furnaces would be practically no more than it now is to the charge-car pit4 ,the furnace top would1 of course1 have to be arranged so that the buggies1 in discharging1 could be drawn along the slot1 so as to give the necessary longitudinal distribution parallel to the furnace walls1 just as is now done in filling the charge-car4 ,the ends of the spreader1 if built like a hipped roof1 would secure proper feeding of the front and back4 ,thus1 by eliminating the charge-car1 and with it the necessity for powerful hoisting machinery1 with its expensive repairs and operating costs1 we may greatly simplify the problem of mechanical feeding1 and open the way for the adoption of successful automatic feeding in many existing plants where it is now considered impracticable4 ,,cost ,,of ,,smelting ,,and ,,refining ,,by ,,malvern ,w4 ,,iles 7,august #ah1 #aijj7 ,in the technical literature of lead smelting there is a lamentable lack of data on the subject of costs4 ,the majority of writers consider that they have fulfilled their duties if they discuss in full detail the chemical and engineering sides of the subject1 leaving the industrial consideration of cost to be wrought out by experience4 ,when an engineer or metallurgist collects data on the costs involved in the various smelting operations1 he generally hesitates to give this special information to the public1 as he regards it as private1 or reserves it as stock in trade to be held for his own use4 ,the following tables of cost have been compiled from actual results of smelting and refining at the ,globe works1 ,denver1 ,colo41 and are offered in the hope that they will prove a valuable addition to the literature of lead smelting4 ,these results are offered tentatively1 and1 while true for the periods stated1 they require considerable adjustment to meet the smelting conditions of the present time4 ,,cost ,,of ,,hand-,,roasting ,,per ,,ton 7#bjjj ,,lb47 ,,of ,,ore #ahhg #c4ige #ahhh #d4bhj #ahhi #d4abj #ahij #c4eca #ahia #c4ecj #ahib #ahic #ahid #c4dbi #ahie #b4hjf #ahif #b4hdj #ahig #b4gdj #ahih #b4fbj ,at first the roasting was done mainly by hand roasters2 later two ,brown-,o',harra mechanical furnaces were used1 and the cost was reduced1 but not to the extent usually conceded to this type of furnace1 as the large amount of repairs and the consequent loss of time diminished the apparent gain due to greater output4 ,the figures quoted above may be considered somewhat higher than the average1 as the roasters were charged in proportion with expenses of general management1 office1 etc4 ,in viewing the yearly reduction of costs one must take into consideration many changes in the furnace construction and working1 as well as the items of labor1 fuel1 etc4 ,from #ahhg to #ahii the principal changes in the construction of the hand-roasting furnaces consisted in an increase of width1 #b ft41 which allowed an addition of #bjj lb4 to each ore charge1 and corresponded to a total increase per furnace of #abjj lb4 in #bd hours4 ,in the working of the charge an important change was made in the condition of the product4 ,formerly the material was fused in the fusion-box and drawn from the furnace in a fused or slagged condition2 and while this gave an excellent material for the subsequent treatment in the shaft furnace in that there was very little dusting of the charge1 and a considerable increase in the output of the furnace1 the disadvantages of large losses of lead and silver greatly over-balanced the advantages1 and called for an entire abandonment of the fusion-box4 ,as a result of experience it was found that the best condition of product is a semi-fused or sintered state1 in which the particles of roasted ore have been compressed by pounding the material1 which has been drawn into the slag pots1 with a heavy iron disk4 ,the amount of 8fines0 under these conditions is quite small and depends upon the percentage of lead in the ore1 the degree of heat employed1 and the extent of the compression4 ,the total cost was partly reduced from the lessened labor cost following the financial disturbance of #ahic1 and partly from the reduction in the fuel cost1 the former expensive lump coal being replaced by the slack coals from southern ,colorado4 ,the comparison of the cost of labor by the two methods shows a gain of #ed;c4 a ton in favor of the mechanical furnaces4 ,however1 ,i consider that this gain is a costly one1 and is more than offset by the large amount of high-grade fuel required1 and the expense of repairs not shown in the following table4 ,indeed1 ,i believe that at the end of five or ten years the average cost of roasting per ton by the hand roasters will be even smaller than by these mechanical roasters4 ,to illustrate the details of roasting cost and to furnish a comparison of the hand roasters and mechanical furnaces1 the following table has been prepared3 ,,details ,,of ,,average ,,monthly ,,cost ,,for #ahih ,,of ,,hand ,,roasters ,,and ,,mechanical ,,furnaces ,,hand ,,roasters ,,brown-,o',,harra ,,mechanical ,,furnaces ,,total ,,tons ,month ,,tons ,,roasted,,labor ,,coal ,,general,,labor ,,coal ,,general ,,roasted ,,per ,,day ,,expense ,,expense ,january #e1fia #ahd #a4dg #j4ec #j4hj #j4ib #j4hj #a4cb ,february #e1fgg #bjc #a4dd #j4dd #j4ii #j4gb #j4eh #a4ja ,march #e1hba #ahh #a4ea #j4ec #j4fd #j4gf #j4fd #j4fb ,april #e1dgb #ahb #a4dg #j4dg #j4ga #j4hj #j4fi #j4hg ,may #e1ddd #agf #a4ee #j4ea #j4hd #j4hj #j4fi #j4ha ,june #d1hei #afb #a4eh #j4dh #j4ga #j4ij #j4fh #a4ag ,july #e1fia #ahd #a4ei #j4dh #j4ge #j4gb #j4ef #j4fd ,august #e1iaj #aia #a4ee #j4df #j4hc #j4gb #j4ee #j4ge ,september #e1fgg #ahi #a4ee #j4de #j4gd #j4gc #j4ee #j4fg ,october #f1bed #bjb #a4dh #j4di #j4gb #j4fe #j4ej #j4fj ,november #f1bia #bac #a4db #j4dg #j4hj #j4ff #j4ec #j4gj ,december #e1hgd #aih #a4de #j4dh #j4gh #j4gi #j4fc #j4ha ,average #a4ej #j4dh #j4gg #j4gf #j4fb #j4hc ,total #b4ge #b4ba ,cost of ,smelting4--,the lead-ore mixtures of the ,united ,states1 in addition to lead1 contain gold1 silver and generally copper1 and are treated to save these metals4 ,the total cost of smelting is made up of a large number of items4 ,the questions of locality and transportation1 fuel1 fluxes and labor are the principal factors1 to which must be added the handling of the material to and from the furnace2 the furnace itself1 its size1 shape1 and method of smelting1 the volume and pressure of blast1 etc4 ,the following table of costs1 from #ahhg to #ahih1 shows in a general way the great advance that has been made in the development of smelting1 and the consequent reduction in cost per ton of ore treated3 ,,average ,,cost ,,of ,,smelting1 ,,per ,,ton #ahhg #d4fdd #ahhh #d4ecj #ahhi #d4dhj #ahij #d4cgd #ahia #d4agj #ahib #d4ijf #ahic #c4cge #ahid #c4jbi #ahie #b4ghf #ahif #b4gej #ahig #b4ebj #ahih #b4bfj ,in connection with this table of smelting cost should be considered the changes developed during the interval #ahhg-ahhi1 outlined as follows3 ,,conditions ,,of ,,smelting ,,in #ahhf ,,and #ahii ,,contrasted ,,to ,,show ,,the ,,progress ,,of ,,development ,,area ,,of ,,furnace ,,height ,,of ,,blast ,,pressure1 ,,fore ,,hearth ,,at ,,tuyeres1 ,,charge ,,from ,,lb4 ,,per ,,capacity1 ,,cu4 ,,in4 ,,tuyeres1 ,,ft4 ,,sq4 ,,in4 ,,ft4 #ahhf #cj #ajj #aa #a #f #ahii #db #adj #af #c to #d #abh ,,slag ,,fuel ,,slag ,,removed1 ,,matte ,,removed1 ,,settled ,,lb4 ,,per ,,trip ,,lb4 ,,per #ahhf ,,trip ,in pots ,charcoal ,by hand ,by hand #bhj #bjj #ahii ,in furnaces ,coke ,by locomotive ,by horse #cjjj-fjjj #bjjj-cjjj ,i believe that there is room for further improvement in the substitution of mechanical transportation within the works for hand labor1 and that the fuel cost can be materially reduced by replacing the coke1 which at present contains #af to #bb per cent4 of ash1 by a fuel of purer and better quality4 ,cost of ,refining by the ,parkes ,process4--,in general it may be stated that the average cost of refining base bullion is from #c to #e a ton4 ,this amount is based on the cost of labor1 spelter1 coal1 coke1 supplies1 repairs and general expenses4 ,when the additional items of interest1 expressage1 brokerage and treatment of by-products are considered1 which go to make up the total refining cost1 the amount may be stated approximately as #aj per ton of bullion treated4 ,variations in the cost occur from time to time1 and are due to several causes1 principally the irregularity of the bullion supply and its consequent effect on the work of the plant4 ,when the amount of bullion available for treatment is small1 the plant cannot be run to its maximum capacity1 and the cost per ton will naturally be increased4 ,to illustrate this variation1 the average cost per ton of base bullion refined during nine months in #ahic was3 ,january1 #d4hfd2 ,february1 #e4ghi2 ,march1 #e4jbd2 ,april1 #c4iae2 ,may1 #e4jid2 ,june1 #d4afh2 ,july1 #d4bca2 ,august1 #d4baf2 ,september1 #e4bii4 ,the yearly variation shows but little change1 as the average cost per ton was for #ahic1 #d4ge2 for #ahid1 #c4ii2 for #ahie1 #d4ba2 for #ahif1 #c4ij4 ,in considering the total cost of refining1 the additional factors of interest1 expressage1 parting1 brokerage1 and reworking of by-products must be considered4 ,as the dor silver is treated at the works or elsewhere1 so will the total cost be less or greater4 ,the following table gives the cost in detail1 when the parting is done at the same works3 ,,average ,,monthly ,,cost ,,of ,,refining ,,per ,,ton ,,of ,,bullion ,,treated ,,items #ahie #ahie #ahif ,,average ,,jan4 ,,to ,,july,,july ,,to ,,dec4,,jan4 ,,to ,,july ,labor #b4cea #a4gah #a4hcf #a4ifh ,spelter #j4geg #j4hdj #j4ihg #j4hfa ,coal #j4ehe #j4ddb #j4dfa #j4dif ,coke #j4fcd #j4dah #j4eaa #j4eba ,supplies1 repairs and general expenses #j4cdc #j4bgc #j4beb #j4bhi ,interest #a4hjh #a4jge #a4jgj #a4cag ,expressage #a4cfj #a4jae #j4hhb #a4jhe ,parting and brokerage #b4dhc #b4jhd #a4gif #b4aba ,reworking by-products #a4efg #a4bhf #a4fbe #a4dib ,totals #aa4hhh #i4aea #i4dbj #aj4aea ,tons bullion refined #e1eaa4eh #i1bdi4jg #aj1ajc4dc #h1bhg4ii ,an analysis of the different items of cost is important1 and a brief summary is given below4 ,labor and ,attendance4--,the cost for this item varies but little from year to year1 and its reduction depends1 for the most part1 on a larger yield per man rather than on a reduction of wages4 ,if a man at the same or slightly increased cost can give a larger output1 so will the labor cost per ton be diminished4 ,this result is accomplished by enlarging the furnace capacity and by using appliances which will handle the bullion and its products in an easier and quicker manner4 ,the small size of the furnaces1 settlers and retorts used at modern refineries is open to criticism2 ,i believe that great improvement can be made in this direction4 ,spelter4--,the cost of this item varies with the market conditions1 and will probably be changed but little in the future1 as the amount necessary per ton of bullion seems to be fixed4 ,coal4--,the amount required per ton of bullion is fairly constant1 and while lessened cost for fuel may be attained by the substitution of oil or gaseous fuel1 the fuel cost in comparison with the aggregate cost is very small1 and leaves little opportunity for improvement in this line4 ,supplies4--,this item includes brooms1 shovels1 wheelbarrows1 etc41 and the amount is small and fairly constant from year to year4 ,repairs4--,this item is quite small in works properly constructed2 and in this connection ,i wish to call particular attention to the floor covering1 which should be made of cast-iron plates from #a4e to #b in4 thick1 and placed on a #b to #c in4 layer of sand spread over the well-tamped and leveled ground4 ,the constant patching of brick floors is not only an annoyance1 but is costly from the additional labor required4 ,furthermore1 a brick floor does not permit a close saving of the metallic scrap material4 ,it will be found economical in the long run to protect all exposed brickwork of furnaces or kettles with sheet iron4 ,in the construction of the refinery building ,i should advise brick walls except at the end or side1 where there is the greatest likelihood of future extension2 here corrugated iron may be used4 ,the roof should not be made of corrugated iron1 as condensed or leakage water is liable to collect and drop on those places where water should be scrupulously avoided4 ,the presence of water in a mold at the time of casting1 even though small in amount1 will cause explosions and will scatter the molten lead1 endangering the workmen4 ,the item of repair for the ordinary corrugated iron roof may be diminished by constructing it of #a in4 boards with intervening spaces of half an inch1 the whole overlaid with tarred felt1 and covered with sheets of iron at least ,no4 #bg ,b4 ,w4 ,g41 painted with graphite paint and joined together with parallel rows of ribbed crimped iron4 ,general ,expenses4--,this item is generally constant1 and calls for no special comment4 ,interest4--,this important item is1 as a rule1 considerable1 as the stock of bullion and other gold-and silver-bearing material is quite large4 ,for this reason special attention should be given to prevent the accumulation of stock or by-products4 ,the occasional necessity of additional capital to run the business should preferably be met by an increase of working capital1 rather than by a direct loan4 ,expressage4--,this item1 as a rule1 is large1 and should be taken into consideration in the original plans for the location of the refining works4 ,parting4--,the item of parting and brokerage is the largest of the refinery costs1 and for obvious reasons a modern smelting plant should have a parting plant under its own control4 ,the ,working of the ,by-,products4--,this constitutes a large item of cost1 and considerable attention should be devoted to the improvement of present methods1 which seem faulty1 slow and expensive4 ,summary4--,the items of smaller cost with their respective amounts per ton of base bullion treated are3 ,spelter1 #j4he2 coal1 #j4ej2 coke1 #j4ej2 supplies1 repairs and general expenses1 #j4ce2 total1 #b4aj4 ,it is doubtful whether much improvement can be made in the reduction of these costs4 ,the items of larger cost are3 ,labor1 #b2 interest1 #a4cb2 expressage1 #a4aj2 parting and brokerage1 #b2 reworking by-products1 #a4ej2 total1 #g4ib4 ,the general manager usually attends to the items of interest1 expressage and brokerage1 leaving the questions of labor and working of by-products to the metallurgist4 ,the cost quoted for smelting practice1 as employed at ,denver1 will differ necessarily from those at other localities1 where the cost of labor1 freight rates on spelter1 fuel1 etc41 are changed4 ,refining can doubtless be done at a lower cost at points along the ,mississippi ,river1 and even more so at cities on the ,atlantic seaboard1 as ,newark or ,perth ,amboy1 ,n4 ,j4 ,the consolidation of many of the more important smelting plants of the ,united ,states under one management will doubtless alter the figures of cost given above1 particularly as the interest cost there stated is at the high rate of #aj per cent41 a condition of affairs now changed to #e per cent4 ,other factors have lessened the cost of refining2 the bullion produced at the present time is softer1 or contains a smaller amount of impurities1 and admits of easier working with shorter time and less labor4 ,by proper management larger tonnages are turned out per man1 and the ,howard stirrer and ,howard press have simplified and cheapened the working of the zinc skimmings4 ,to illustrate the comparatively recent conditions of cost ,i have compiled the following table for each month of the year #ahih3 ,,cost ,,of ,,refining ,,during #ahih1 ,,including ,,labor1 ,,spelter1 ,,coal1 ,,coke1 ,,supplies1 ,,repairs ,,and ,,general ,,expenses4 ,january #c4ei ,february #c4bh ,march #c4bf ,april #c4ei ,may #c4ch ,june #c4ef ,july #c4fe ,august #c4ed ,september #c4ce ,october #c4de ,november #c4bj ,december #c4ef ,average cost during the year1 #c4de4 ,it is understood1 of course1 that these figures do not include cost of interest1 expressage1 parting1 brokerage and reworking of by-products4 ,although this article refers to conditions in #ahih1 since which time there have been improvements in practice1 the latter have not been of radical character and the figures given are fairly representative of present conditions4--,,editor4 ,,smelting ,,zinc ,,retort ,,residues#ac ,,by ,e4 ,m4 ,,johnson 7,march #bb1 #aijf7 ,the following notes were taken from work done at the ,cherokee ,lanyon ,smelter ,company1 ,gas1 ,kansas1 in #aijc4 ,it was practically an experiment4 ,the furnace was only #cf #ij in4 at the crucible1 with a #aj in4 side bosh and a #f in4 end bosh4 ,there were five tuyeres on each side with a #c in4 opening4 ,the side jackets measured #d4e ft4 #ah in4 ,the distance from top of crucible to center of tuyeres was #aa4e in4 ,the blast was furnished by one ,no4 #d ,connellsville blower4 ,the furnace originally was only #aa ft4 from the center of tuyeres to the feed-floor1 and had only been saving about #fj per cent4 of the lead4 ,this loss of lead1 however1 was not entirely due to the low furnace4 ,as no provision had been made to separate the slag and matte1 upon assuming charge ,i raised the feed-floor #c ft41 thereby changing the distance from the tuyere to top of furnace from #aa ft4 to #ad ft4 ,matte settlers were also installed4 ,these two changes raised the percentage of lead saved to #ib1 as shown by monthly statements4 ,the furnace being small1 and a high percentage of zinc oxide on the charge1 the campaigns were naturally short4 ,the longest run was about six weeks4 ,this was made on some residue that had been screened from the coarse coal1 and coke1 and had weathered for several months4 ,this particular residue also carried about #aj per cent4 lead4 ,the more recent residue that had not been screened and weathered1 and was low in lead1 did not work so well4 ,although these residues consisted of a large proportion of coal and coke1 it seemed impossible to reduce the percentage of good lump coke on the charge lower than #ab4e or #ac per cent4 ,at the same time the reducing power of the residue was strong1 and with the normal amount of coke caused some trouble in the crucible4 ,when residue containing semi-anthracite coal was smelted1 the saving in lead dropped1 and the fire went to the top of the furnace1 burning with a blue flame1 thereby necessitating the reduction of this class of material4 ,this residue had been screened through a five-mesh screen1 and wet down in layers1 becoming so hard that it had to be blasted4 ,the low saving of lead with this class of material was a surprise1 as it has been claimed that the substitution of part of the fuel by anthracite coal did not affect the metallurgical operations of the furnace4 ,the slag was quite liquid and flowed very well at all times4 ,however1 there was a marked variation in the amount at different tappings4 ,this1 ,i am satisfied1 was not due to irregular work on the furnace1 but may be accounted for in the following manner4 ,the residue 7not screened or weathered to any extent71 consisting approximately of one-half coal and coke1 was very bulky1 and while there was about #ce per cent4 of it on the charge by weight1 there was over #ej per cent4 of it by bulk1 not including slag and coke4 ,in feeding1 therefore1 it was a difficult matter to mix the whole of it with the charge4 ,several different ways of feeding the furnace were tried4 ,the one giving the most satisfactory results was to feed nearly all of the residue along the center of the furnace1 in connection with the lime-rock1 coarse ore and coarse iron ore1 and the fine and easy smelting ores along the sides4 ,the slag was spread uniformly over the whole furnace1 while the sides were favored with the coke4 ,the charge would drop several inches at a time1 going down a little faster in the center than on the sides4 ,it is possible that a small proportion of the residue in connection with the easy smelting1 leady1 neutral ore1 iron ore and lime-rock formed the type of slag marked ,no4 #a4 ,si,o ,fe,o ,mn,o ,ca,o ,zn,o ,pb ,ag #a #cc4g #cd4a #a4j #af4e #g4e #j4i #j4g #b #ca4j #cf4a #a4b #af4j #i4f #a4c ,this being tapped with a good flow of slag1 the charge would drop1 bringing a proportionately large amount of residue in the fusion zone which formed the type of slag marked ,no4 #b4 ,there was also a marked variation in the slag-shells from different pots4 ,the above cited irregularities of course exist to a certain extent in any blast furnace4 ,,average ,,analysis ,,of ,,materials ,,smelted ,,name ,,row ,,name ,,row ,mo4 iron ore ,a ,roasted matte#ae ,f ,lime rock ,b ,barrings ,g ,mo4 galena ,c ,coke ash ,h ,av4 of beds ,d ,coke#af ,j ,residue#ad ,e ,si,o ,fe,o ,ca,o ,mg,o ,zn,o ,al,o ,fe,o ,s ,pb ,cu ,ag ,au ,a #aj4j #fe4j ,b #a4e #eb4j ,c #a4e #b4d #i4e #aa4jgd4j ,d #ej4h #af4b #d4f #c4c #i4a ,e #aj4e #ch4e #ah4j #d4h #b4ba4jaj4jj4jc ,f #i4j #dh4j #c4j #aj4j #d4j #i4ic4jba4jj4jf ,g #ah4h #bd4d #e4j #ad4e #f4jbe4d #ac4jj4jg ,h #bg4j #ad4i #d4e #ai4g #ca4f ,h,o ,v4,m4,f4,c4 ,ash ,s ,j #a4b #b4c #he4gaa4a #j4i ,,analysis ,,of ,,bullion1 ,,slag ,,and ,,matte ,,produced _/-,,bullion- _/--------------------------,,slag------ -------------------------_/---------,,ma tte--------- ,ag ,au ,si,o ,fe,o ,mn,o,ca,o ,zn,o ,pb ,ag ,ag ,au ,pb ,cu ,feb4 #ij4j #a4aeca4b #ce4ia4jad4eaj4cj4hhj4ihai4jj4jdh4ga4e ,march #ic4a #a4fcca4c #cg4ba4jac4iaa4aj4gaa4cjba4jj4jfh4jb4e ,april#ajd4c #a4eibi4h #cg4gb4gac4iaa4dj4eba4djbc4jj4jgg4jc4e ,may #ij4j #a4bdcj4j #cg4cb4bad4a #i4cj4hfa4ajbe4dj4jge4ad4j ,july #gh4g #a4jjcb4b #cg4da4jac4i #i4hj4eja4aeba4cj4jch4id4j ,aug4 #ij4h #a4baca4b #cg4a #a4gac4g #i4fa4aja4fjbc4aj4jhi4hc4j ,sept4 #fe4c #b4ehcb4j #ci4gj4had4a #h4aj4hja4cjah4fj4jfg4fb4c ,avge4 #hg4e #a4dica4a #cg4ea4ead4aaj4jj4gga4bfba4fj4jfg4hc4j ,,monthly ,,record ,,of ,,furnace ,,operations ,,blast ,,tons ,,per ,,cent4,,per ,,cent4,,per ,,cent4,,per ,,cent4 ,,ounces ,,per ,,pb4 ,,on ,,coke ,,on ,,slag ,,on ,s ,,on ,f4,d4 ,,charge ,,charge ,,charge ,,charge ,feb4 #ba #db4e #i4j #ab4j #cj4j #c4g ,march #ba #dd4h #i4g #ac4e #cg4j #d4j ,april #ba #dc4g #i4j #ac4e #ce4j #d4c ,may #ba #di4d #aj4j #ac4e #cj4j #c4e ,july #ag #da4j #i4h #ab4e #cd4j #c4h ,august #ah #dg4j #i4c #ac4j #cb4j #c4g ,sept4#ag #ae #ea4j #g4c #ac4j #cj4j #b4h ,average #de4f #i4a #ac4j #cb4f #c4g ,,matte ,,saving ,,produced ,,ag ,,au ,,pb ,feb4 #h4j #hd4d #hc4j #ij4c ,march #i4j ,april #aj4j #ig4i #gj4e #if4f ,may #f4e #ie4f #aji4e #hh4h ,july #f4j #ig4i #ij4j #ib4i ,august #f4c #hf4b #ajg4e #hg4f ,sept4 #d4f #ib4i #id4j #ie4f ,average #g4b #ij4h #ib4d #ib4j ,i believe that1 in smelting residues high in zinc oxide1 better metallurgical results would be obtained by using a dry silicious ore in connection with a high-grade galena ore1 provided the residue be low in sulphur4 ,this was confirmed to a certain degree in actual practice1 as the furnace worked very well upon increasing the percentage of ,cripple ,creek ore on the charge4 ,this would also seem to indicate that alumina had no bad effect on a zinky slag4 ,,zinc ,,oxide ,,in ,,slags ,,by ,w4 ,,maynard ,,hutchings 7,december #bd1 #aijc7 ,from time to time1 in various articles and letters on metallurgical subjects in the ,engineering and ,mining ,journal1 the question of the removal of zinc oxide in slags is referred to1 and the question is raised as to the form in which it is contained in the slags4 ,i gather that opinion is divided as to whether zinc oxide enters into the slags as a combined silicate1 or whether it is simply carried into them in a state of mechanical mixture4 ,for many years ,i have taken great interest in the composition of slags1 and have studied them microscopically and chemically4 ,the conclusion to which ,i have been led as regards zinc oxide is1 that in a not too basic slag it is originally mainly1 if not wholly1 taken up as silicate along with the other bases4 ,on one occasion1 one of my furnaces for several days produced a slag in which beautiful crystals of willemite were very abundant1 both free in cavities and also imbedded throughout the mass of solid slag1 as shown in thin sections under the microscope4 ,in the same slag was a large amount of magnetite1 all of which contained a considerable proportion of zinc oxide combined with it4 ,magnetite crystals1 separated out from the slag and treated with strong acid1 yielded shells of material retaining the form of the original mineral1 rich in zinc oxide2 an inter-crystallized zinc-iron spinel1 in fact4 ,i have seen and separated zinc-iron spinels very rich in zinc oxide from other slags4 ,they have been seen in the slags at ,freiberg2 and of course everybody knows the very interesting paper by ,stelzner and ,schulze1 in which they described the beautiful formations of spinels and willemite in the walls of the retorts of zinc works4 ,i think there is thus good ground for concluding that zinc oxide is slagged off as combined silicate1 and that free oxide does not exist in slags2 though zinc oxide does occur in them after solidification1 combined with other oxides1 in forms ranging from a zinkiferous magnetite to a more or less impure zinc-iron1 or zinc-iron-alumina spinel1 these minerals having crystallized out in the earlier stages of cooling4 ,the microscope showed that the crystals of willemite1 mentioned above1 were the first things to crystallize out from the molten slag4 ,the main constituent was well-crystallized iron-olivine-fayalite4 ,,part ,v ,,lime-,,roasting ,,of ,,galena ,,the ,,huntington-,,heberlein ,,process 7,july #f1 #aije7 ,it is a fact1 not generally known1 that the ,american ,smelting and ,refining ,company is now preparing to introduce the ,huntington-,heberlein process in all its plants1 this action being the outcome of extensive experimentation with the process4 ,it is contemplated to employ the process not only for the desulphurization of all classes of lead ore1 but also of mattes4 ,this is a tardy recognition of the value of a process which has been before the metallurgical profession for nine years1 the ,british patent having been issued under date of ,april #af1 #ahif1 and has already attained important use in several foreign countries2 but it will be the grandest application in point of magnitude4 ,the ,huntington-,heberlein is the first of a new series of processes which effect the desulphurization of galena on an entirely new principle and at great advantage over the old method of roasting4 ,they act at a comparatively low temperature1 so that the loss of lead and silver is reduced to insignificant proportion2 they eliminate the sulphur to a greater degree2 and they deliver the ore in the form of a cinder1 which greatly increases the smelting speed of the blast furnace4 ,they constitute one of the most important advances in the metallurgy of lead4 ,the roasting process has been the one in which least progress has been made1 and it has remained a costly and wasteful step in the treatment of sulphide ores4 ,in reducing upward of #b1ejj1jjj tons of ore per annum1 the ,american ,smelting and ,refining ,company is obliged to roast upward of #a1jjj1jjj tons of ore and matte4 ,the ,huntington-,heberlein process was invented and first applied at ,pertusola1 ,italy4 ,it has since been introduced in ,germany1 ,spain1 ,great ,britain1 ,mexico1 ,british ,columbia1 ,tasmania1 and ,australia1 in the last at the ,port ,pirie works of the ,broken ,hill ,proprietary ,company4 ,efforts were made to introduce it in the ,united ,states at least five years ago1 without success and with little encouragement4 ,the only share in this metallurgical improvement that this country can claim is that ,thomas ,huntington1 one of the inventors1 is an ,american citizen1 ,ferdinand ,heberlein1 the other1 being a ,german4 ,,lime-,,roasting ,,of ,,galena 7,september #bb1 #aije7 ,the article of ,professor ,borchers 7see p4 #aaf7 is1 we believe1 the first critical discussion of the reactions involved in the new methods of desulphurizing galena1 as exemplified in the processes of ,huntington and ,heberlein1 ,savelsberg1 and ,carmichael and ,bradford1 although the subject has been touched upon by ,donald ,clark1 writing in the ,engineering and ,mining ,journal4 ,it is perfectly obvious from a study of the metallurgy of these processes that they introduce an entirely new principle in the oxidation of galena1 as ,professor ,borchers points out4 ,inasmuch as there are already three of these processes and are likely to be more1 it will be necessary to have a type-name for this new branch of lead metallurgy4 ,we venture to suggest that it may be referred to as the 8lime-roasting of galena10 inasmuch as lime is evidently a requisite in the process2 or1 at all events1 it is the agent which will be commonly employed4 ,when the ,huntington-,heberlein process was first described1 it did not even appear a simplification of the ordinary roasting process1 but rather a complication of it4 ,the process attracted comparatively little attention1 and was indeed regarded somewhat with suspicion4 ,this was largely due to the policy of the company which acquired the patent rights in refusing to publish the technical information concerning it that the metallurgical profession expected and needed4 ,the history of this exploitation is another example of the disadvantage of secrecy in such matters4 ,the ,huntington-,heberlein process has only become thoroughly established as a new and valuable departure in metallurgy1 a departure which is indeed revolutionary1 nine years after the date of the original patent4 ,in proprietary processes time is a particularly valuable element1 inasmuch as the life of a patent is limited4 ,from the outset the explanation of ,huntington and ,heberlein as to the reactions involved in their process was unsatisfactory4 ,professor ,borchers points out clearly that their conception of the formation of calcium peroxide was erroneous1 and indicates strongly the probability that the active agent is calcium plumbate4 ,it is very much to be regretted that he did not go further with his experiments on this subject1 and it is to be hoped that they will be taken up by the professors of metallurgy in other metallurgical schools4 ,the formation of calcium plumbate in the process was clearly forecasted1 however1 by ,carmichael and ,bradford in their first patent specification2 indeed1 they considered that the sintered product consisted largely of calcium plumbate4 ,even yet1 we have only a vague idea of the reactions that occur in these processes4 ,there is undoubtedly a formation of calcium sulphate1 as pointed out by ,borchers and ,savelsberg2 but that compound is eventually decomposed1 since it is one of the advantages of the lime-roasting that the sintered product is comparatively low in sulphur4 ,is it true1 however1 that the calcium eventually becomes silicate8 ,if so1 under what conditions is calcium silicate formed8 ,the temperature maintained throughout the process is low1 considerably lower than that required for the formation of any calcium silicate by fusion4 ,moreover1 it is not only galena which is decomposed by the new method1 but also blende1 pyrite and copper sulphides4 ,the process is employed very successfully in the treatment of ,broken ,hill ore that is rather high in zinc sulphide1 and it is also to be employed for the desulphurization of mattes4 ,what are the reactions that affect the desulphurization of the sulphides other than lead8 ,there is a wide field for experimental metallurgy in connection with these new processes4 ,the important practical development is that they do actually effect a great economy in the reduction of lead sulphide ores4 ,,the ,,new ,,methods ,,of ,,desulphurizing ,,galena#ah ,,by ,w4 ,,borchers 7,september #b1 #aije7 ,an important revolution in the methods of smelting lead ore1 which had to a large extent remained for centuries unchanged in their essentials1 was wrought by the invention of ,huntington and ,heberlein in #ahif4 ,more especially is this true of the roast-reduction method of treating galena1 which consists of oxidizing roasting in a reverberatory furnace and subsequent smelting of the roasted product in a shaft furnace4 ,the first stage of the roast-reduction process1 as carried out according to the old method1 viz41 the oxidizing roast of the galena1 serves to convert the lead sulphide into lead oxide3 ,pb,s #c,o ,pb,o ,,so4 ,owing to the basic character of the lead oxide1 the production of a considerable quantity of lead sulphate was of course unavoidable3 ,pb,o ,,so ,o ,pb,s,o4 ,as this lead sulphate is converted back into sulphide in the blast-furnace operation1 and so adds to the formation of matte1 it has always been the aim 7in working up ores containing little or no copper to be concentrated in the matte7 to eliminate the sulphate as completely as possible1 by bringing the charge1 especially toward the end of the roasting operation1 into a zone of the furnace wherein the temperature is sufficiently high to effect decomposition of the sulphate by silica3 ,pb,s,o ,si,o ,pb,si,o ,,so4 ,but in the usual mode of carrying out the roast in reverberatory furnaces1 the roasting itself on the one hand1 and the decomposition of the sulphates on the other1 were effected only incompletely and with widely varying results4 ,little attention has been paid in connection with the roast-reduction process to the reaction between sulphates and undecomposed sulphides1 which plays so important a part in the roast-reaction method of lead smelting4 ,as is well known1 lead sulphate reacts with lead sulphide in varying quantities1 forming either metallic lead or lead oxide1 or a mixture of both4 ,a small quantity of lead sulphate reacting with lead sulphide yields under certain conditions only lead3 ,pb,s,o ,pb,s ,pb #b,,so4 ,within certain temperature limits this reaction even proceeds with liberation of heat4 ,in order to encourage it1 it is necessary to create favorable conditions for the formation of considerable quantities of sulphate right at the beginning of the operation4 ,this was first achieved by ,huntington and ,heberlein1 but not in the simplest nor in the most efficient manner4 ,and1 indeed1 the inventors were not by any means on the right track as to the character of their process1 so far as the chemical reactions involved are concerned4 ,at first sight the ,huntington-,heberlein process does not even appear as a simplification1 but rather as a complication1 of the roasting operation4 ,for in place of the roast carried out in one apparatus and continuously1 there are two roasts which have to be carried out separately and in two different forms of apparatus2 nevertheless1 the ultimate results were so favorable that the whole process is presumably acknowledged1 without reservation1 by all smelters as one of the most important advances in lead smelting4 ,it is useful to examine in the light of the ,german patent specification 7,no4 #ie1fja of ,feb4 #bh1 #ahig7 what were the ideas of its originators regarding the operation of this process and the reactions leading to such remarkable results4 ,they stated3 8,we have made the observation that when powdered lead sulphide 7,pb,s71 mixed with the powdered oxide of an alkaline earth metal1 e4g41 calcium oxide1 is exposed to the action of air at bright red heat 7about #gjj deg4 ,c471 and is then allowed to cool without interrupting the supply of air1 an oxidizing decomposition takes place when dark-red heat 7about #ejj deg4 ,c47 is reached1 sulphurous acid being expelled1 and a considerable amount of heat evolved2 if sufficient air is then continuously passed through the charge1 dense vapors of sulphurous acid escape1 and the mixture gradually sinters together to a mass1 in which the lead of the ore is present in the form of lead oxide1 provided the air blast is continued long enough2 there is no need to supply heat in this process--the heat liberated in the reaction is quite sufficient to keep it up40 ,the inventors explained the process as follows3 8,at a bright-red heat the calcium oxide 7,ca,o7 takes up oxygen from the air supplied1 forming calcium peroxide 7,ca,o71 which latter afterward1 in consequence of cooling down to dark-red heat1 again decomposes into monoxide and oxygen2 this nascent oxygen oxidizes a part of the lead sulphide to lead sulphate1 which then reacts with a further quantity of lead sulphide1 with evolution of sulphur dioxide and formation of lead oxide40 ,assuming the formation of calcium peroxide 7,ca,o71 the process leading to the desulphurization would therefore be represented as follows3 #a4 at #gjj ,c4 ,ca,o ,o ,ca,o #b4 at #ejj ,c4 #d;,ca,o ,pb,s #d;,ca,o ,pb,s,o #c4 at the melting point ,pb,s ,pb,s,o #b,pb,o #b,,so 787 ,reactions #a and #b combined1 assuming the presence of sufficient oxygen1 give3 ,pb,s #d;,ca,o #d,o ,pb,s,o #d;,ca,o4 ,now the invention consists in applying the observation described above to the working up of galena1 and other ores containing lead sulphide1 for metallic lead2 and the essential novelty of the process therefore consists in passing air through the mass cooled to a dark-red heat 7#ejj deg4 ,c474 ,this feature sharply distinguishes it from other known processes4 ,it is true that in previous processes 7compare the ,tarnowitz reverberatory-furnace process1 the roasting process used at ,munsterbusch near ,stolberg1 and others7 the lead ore was mixed with limestone or dolomite 7which are converted into oxides in the early stage of the roast7 and the heat was alternately raised and lowered2 but in all cases only a surface action of the air was produced1 the air supply being provided simply by the furnace draft4 ,passing air through the mass cooled down1 as indicated above1 leads to the important economic advantages of reducing the fuel consumption1 the losses of lead1 the manual labor 7raking7 and the dimensions of the roasting apparatus4 ,in order to carry out the process of this invention1 the powdered ore is intimately mixed with a quantity of alkaline earth oxide1 e4g41 calcium oxide1 corresponding to its sulphur content2 if the ore already contains alkaline earth1 the quantity to be added is reduced in accordance4 ,the mixture is heated to bright-red heat 7#gjj deg4 ,c47 in the reverberatory furnace1 in a strongly oxidizing atmosphere1 is then allowed to cool down to dark-red heat 7#ejj deg4 ,c471 also in strongly oxidizing atmosphere1 is transferred to a vessel called the 8converter10 and atmospheric air is passed through at a slight pressure 7the inventors have found a blast corresponding to #ce to #dj cm4 head of water suitable74#ai ,the heat liberated is quite sufficient to keep the charge at the reaction temperature1 but1 if desired1 hot blast may also be used4 ,the mixture sinters together1 and 7while sulphurous acid gas escapes7 it is gradually converted into a mass consisting of lead oxide1 gangue and calcium sulphate1 from which the lead is extracted in the metallic form1 by any of the known methods1 in the shaft furnace4 ,the operation is concluded as soon as the mass1 by continued sintering1 has become impermeable to the blast4 ,if the operation is properly conducted1 the gas escaping contains only small quantities of volatile lead compounds1 but on the other hand up to #h per cent4 by volume of sulphur dioxide4 ,this latter can be collected and further worked up4 8,in place of the oxide of an alkaline earth1 ferrous oxide 7,fe,o7 or manganous oxide 7,mn,o7 may also be used40 ,according to the reports on the practice of this process which have been published1#bj conical converters of about #agjj mm4 7#e ft4 #f in47 upper diameter and #aejj mm4 7#e ft47 depth are used in ,australian works4 ,at a new plant at ,port ,pirie 7,broken ,hill ,proprietary ,company7 converters #bdjj mm4 7#g ft4 #aj in47 in diameter and #ahjj mm4 7#e ft4 #aa in47 deep have been installed4 ,these latter will hold a charge of about eight tons4 ,in the lower part of these converters1 at a distance of about #fjj mm4 7#b ft47 from the bottom1 there is placed an annular perforated plate1 and upon this a short perforated tube1 closed above by a plate having only a limited number of holes4 ,no details have been published with regard to the ,european installations4 ,the general information which the ,metallurgische ,gesellschaft#ba placed at my disposal upon request some years ago1 for use in my lecture courses1 was restricted to data regarding the consumption of fuel and labor in roasting and smelting the ores1 which was figured at about one-third or one-half of the consumption in the former processes1 to the demonstration of the large output of the comparatively small converters1 and to the reduced size of the roasting plant as the result4 ,but the ,european establishments which introduced this process were bound by the owners of the patents1 notwithstanding the protection afforded by the patents1 to give no information whatever regarding the process to outsiders1 and not to allow any inspection of the works4 ,on the other hand1 a great deal appeared in technical literature which was calculated to excite curiosity4 ,moreover1 as professor of metallurgy1 it was my duty to instruct my pupils concerning this process among others1 and it was therefore very gratifying to me that one of the students in my laboratory took a special interest in the treatment of lead ore4 ,i gave him opportunity to install a small converter1 in order to carry out the process on a small scale1 and in spite of the slender dimensions of the apparatus the very first experiments gave a complete success4 ,however1 ,i could not harmonize the explanation of the process given by the inventors with the knowledge which ,i had acquired in my many years' practical experience in the manufacture of peroxides4 ,it is clear from the patent specification that in the roasting operation at #gjj deg4 ,c4 a compound must be formed which functions as an excellent oxygen carrier1 for on cooling to #ejj deg4 ,c4 the further oxidation then proceeds to the end not only without any external application of heat1 but even with vigorous evolution of heat4 ,no more striking instance than this could be desired by the theorists who have of recent years again become so enthusiastic over the idea of catalysis4 ,huntington and ,heberlein regarded calcium peroxide as the oxygen carrier1 but that is a compound which cannot exist at all under the conditions which obtain in their process4 ,the peroxides of the alkaline earths are so very sensitive that in preparing them the small quantities of carbon dioxide and water must be extracted carefully from the air1 and yet in the process1 in an atmosphere pregnant with carbon dioxide1 water1 sulphurous acid1 etc41 calcium peroxide1 the most sensitive of the whole group1 is supposed to form6 ,this could not be4 ,the only compounds known as oxygen carriers1 and capable of existing under the conditions of the process1 are calcium plumbate and plumbite4 ,i have emphasized this point from the first in my lectures on metallurgy1 when dealing with the ,huntington-,heberlein process1 and1 in point of fact1 this assumption has since been proved to be correct by the work of ,l4 ,huppertz1 one of my students4 ,during my practical activity 7#ahgi-ahia7 ,i had prepared barium peroxide and lead peroxide in large quantities on a manufacturing scale1 the last-mentioned through the intermediate formation of plumbites and plumbates3 #b,na,o,h ,pb,o ,o ,na,pb,o ,h,o or3 #d,na,o,h ,pb,o ,o ,na,pb,o #b;,h,o4 ,an experiment made in this connection showed that calcium plumbate is formed just as readily from slaked lime and litharge as the sodium plumbates above4 ,litharge is an intermediate product1 produced in large quantities in lead works1 and must in any case be brought back into the process4 ,if1 then1 the litharge is roasted at a low temperature with slaked lime1 the roasting of the galena could perhaps be entirely avoided by introducing that ore together with calcium plumbate into the converter1 after the latter had once been heated up4 ,mr4 ,huppertz undertook the further development of this process1 but ,i have no information on the later experimental results1 as he placed himself in communication with neighboring lead works for the purpose of continuing his investigation1 and has not since then given me any precise data4 ,i will therefore confine myself to the statement that the fundamental idea for the experiments1 which ,mr4 ,huppertz undertook at my suggestion1 was the following3 ,to dispense with the roasting of the galena1 which is necessary according to ,huntington and ,heberlein2 in other words1 to convert the galena by direct blast1 with the addition of calcium plumbate1 the latter being produced from the litharge which is an unavoidable intermediate product in the metallurgy of lead and silver4 7,borchers1 8,elektrometallurgie10 #c;d edition1 #aijb-aijc1 p4 #dfg47 ,this alone would1 of course1 have meant a considerable simplification of the roast1 but the problem of the roasting of galena has been solved in a better way by ,a4 ,savelsberg1 of ,ramsbeck1 ,westphalia1 who has determined the conditions for directly converting the galena with the addition of limestone and water and without previous roasting4 ,he has communicated the following information regarding these conditions3 ,in order that1 in blowing the air through the mixture of ore and limestone1 an alteration of the mixture may not take place owing to the lighter particles of the limestone being carried away1 it is necessary 7quite at variance with the processes in use hitherto1 in which for the sake of economy stress is laid on the precaution of charging the ore as dry as possible into the apparatus7 to add a considerable quantity of water to the charge before introducing it into the converter4 ,the water serves this purpose perfectly1 also preventing any change in the mixture of ore and limestone1 which invariably occurs if the ore is used dry4 ,the water1 moreover1 exerts a very beneficial action in the process1 inasmuch as it aids materially in the formation and temporary retention of sulphuric acid1 which latter then1 by its oxidizing action1 greatly enhances the reaction and consequently the desulphurization of the ore4 ,furthermore1 the water tends to moderate the temperature in the charge by absorbing heat in its volatilization4 ,in carrying out the process the converter must not be filled entirely all at once1 but first only in part1 additional layers being charged in gradually in the course of the operation4 ,in this way a uniform progress of the reaction in the mass is secured4 ,the following mode of procedure is advantageously adopted3 ,a small quantity of glowing fuel 7coal1 coke1 etc47 is introduced into the converter1 which is provided at the bottom with a grate 7perforated sheet iron71 the grate being first covered with a thin layer of crushed limestone in order to protect it from the action of the red-hot coals and ore4 ,upon this red-hot fuel a uniform layer of the wetted mixture of crude ore and limestone is placed4 ,when the surface of the first layer has acquired a uniform red heat1 a fresh layer is charged on1 and this is continued1 layer by layer1 until the converter is quite full4 ,while the layers are still being put on1 the blast is passed in at quite a low pressure1 and only when the converter is entirely filled is the whole force of the blast1 at a rather greater pressure1 turned on4 ,there then sets in a kind of slag formation1 which1 however1 is preceded by a very vigorous desulphurization4 ,after the termination of the process1 which can be recognized by the fact that vapors cease to be evolved1 and that the surface of the ore becomes hard1 the converter is tipped over1 and the desulphurized mass drops out as a solid cone of slag1 which is then suitably broken up for the subsequent smelting in the shaft furnace4 ,savelsberg explains the reaction of this process as follows3 8#a4 ,the particles of limestone act mechanically1 gliding in between the particles of lead ore and separating them from one another4 ,in this way a premature sintering is prevented1 and the whole mass is rendered loose and porous4 8#b4 ,the limestone moderates the reaction temperature produced in the combustion of the sulphur1 so that the fusion of the galena1 the formation of dust and the separation of metallic lead are avoided1 or at least kept within the limits permissible4 ,the lowering of the temperature of reaction is due partly to the decomposition of the limestone into caustic lime and carbon dioxide1 in which heat is absorbed1 and partly to the consumption of the quantity of heat which is necessary in the further progress of the operation for the formation of a slag from the gangue of the ore and the lead oxide produced4 8#c4 ,the limestone gives rise to chemical reactions4 ,by its decomposition it produces lime1 which1 at the moment of its formation1 is converted into calcium sulphate at the expense of the sulphur in the ore4 ,the calcium sulphate at the time of slag formation is converted into silicate by the silica present1 sulphuric acid being evolved4 ,the limestone therefore assists directly and forcibly in the desulphurization of the ore1 causing the formation of sulphuric acid at the expense of the sulphur in the ore1 the sulphuric acid then acting as a strong oxidizing agent toward the sulphur in the ore40 ,the most conclusive proof for the correctness of the opinion which ,i expressed above1 that it is very important to create at the beginning of the operation the conditions for the formation of as much sulphate as possible1 has been furnished by ,carmichael and ,bradford4 ,they recommend that gypsum be added to the charge in place of limestone4 ,at one of the works of the ,broken ,hill ,proprietary ,company 7where their process has been carried on successfully1 and where lead ores very rich in zinc had to be worked up7 the dehydrated gypsum was mixed with an equal quantity of concentrate and three times the quantity of slime from the lead ore-dressing plant1 as in the table given herewith3 ,,of ,,the ,,of ,,the ,,of ,,the ,,of ,,the ,,contents ,,slime ,,concentrate ,,calcium ,,whole ,,sulphate ,,charge ,galena #bd #gj #bi ,zinc blende #cj #ae #ba ,pyrites #c #b ,ferric oxide #d #b4e ,ferrous oxide #a #a ,manganous oxide #f4e #e ,alumina #e4e #c ,lime #c4e #d4a #aj ,silica #bc #ad ,sulphur trioxide #ei #ab ,the charge is mixed1 with addition of water1 in a suitable pug-mill4 ,the mass is then1 while still wet1 broken up into pieces #ej mm4 7#b in47 in diameter1 which are then allowed to dry on a floor in contact with air2 in doing so they set hard1 owing to the rehydration of the gypsum4 ,as in the case of the ,savelsberg process1 the converters are heated with a small quantity of coal1 are filled with the material prepared in the manner above described1 and the charge is blown1 regulating the blast in such manner that1 after the moisture present has been dissipated1 a gas of about #aj per cent4 ,,so content is produced1 which is worked up for sulphuric acid in a system of lead chambers4 ,the reactions are in this case the same as in the ,savelsberg process1 for here also calcium sulphate is formed transitorily1 which1 like other sulphates1 reacts partly with sulphides1 partly with silica4 ,where gypsum is available and cheap1 the ,carmichael-,bradford process must be given preference2 in all other cases unquestionably the ,savelsberg process is superior1 owing to its great simplicity4 ,,lime-,,roasting ,,of ,,galena ,,by ,w4 ,,maynard ,,hutchings 7,october #ba1 #aije7 ,much interest attaches to the paper by ,professor ,borchers1 recently presented in the ,engineering and ,mining ,journal 7,sept4 #b1 #aije7 on 8,new ,methods of ,desulphurizing ,galena10 together with an editorial on 8,lime-,roasting of ,galena02 it is a curious coincidence that the same issue contained also an article on the 8,newer ,treatment of ,broken ,hill ,sulphides10 in which is shown the importance of the new methods as a contribution to actual practice4 ,for some years it had been a source of surprise to me that a new process1 so interesting and so successful as the ,huntington-,heberlein treatment of sulphide ores1 should have received scarcely any notice or discussion4 ,this lack1 however1 now appears to be remedied4 ,the suggestion that the subject should be discussed in the ,journal is good1 as is also that of the designation 8,lime-,roasting0 for a type-name4 ,such observations and experiments on the subject as ,i have had occasion to record have1 for many years1 figured in my note-books under that heading4 ,whatever may be the final results of the later processes1 now before the metallurgical world or still to come1 there can be no doubt whatever that full and exclusive credit must be given to ,huntington and ,heberlein1 not only for first drawing attention to the use of lime1 but also for working out and introducing practically the process4 ,it has been a success from the first2 and so far as part of it is concerned1 it seems to be an absolute and fundamental necessity which later inventors can neither better nor set aside4 ,the other processes1 since patented1 however good they may be1 are simply grafts on this parent stem4 ,it is1 however1 quite certain that ,huntington and ,heberlein1 in the theoretical explanation of the process1 failed to understand the most important reactions4 ,their attributing the effect to the formation and action of calcium peroxide affords a sad case of a priori assumption devoid of any shred of evidence4 ,as ,professor ,borchers points out1 calcium peroxide1 so difficult to produce and so unstable when formed1 is an absolute and absurd impossibility under the conditions in question4 ,probably many rubbed their eyes with astonishment on reading that part of the patent on its first appearance1 and hastened to look up the chemical authorities to refresh their minds1 lest something as to the nature of calcium peroxide might have escaped them4 ,fortunately the patent law is such that there was no danger of a really good and sound invention being invalidated by a wrong theoretical explanation by its originators4 ,but1 nevertheless1 it was a misfortune that the inventors did not understand their own process4 ,had they known1 they could have added a few more words to their patent-claims and rendered the ,carmichael patent an impossibility4 ,professor ,borchers appears to consider that the active agent in the new process is calcium plumbate4 ,that this compound may play a part at some stage of the process may be true2 this long ago suggested itself to some others4 ,we may yet expect to hear that the experiments undertaken by ,professor ,borchers himself1 and by others at his instigation 7in which calcium plumbate is separately prepared and then brought into action with lead sulphide71 have given good results4 ,but it does not appear so far that there is any real proof that calcium plumbate is formed in the ,huntington-,heberlein or other similar processes2 and it is difficult to see at what stage or how it would be produced under the conditions in question4 ,this is a point which research may clear up1 but it should not be taken for granted at this stage4 ,indeed1 it seems to me that the results obtained may be fairly well explained without calling calcium plumbate into play at all4 ,of course the action of lime in contact with lead sulphide excited interest many years before the new process came into existence4 ,my own attention to it dates back more than a dozen years before that time 7,i was in charge of works where ,i found the old 8,flintshire process0 still in use74 ,percy pointed out1 in his work on lead smelting1 that on the addition of slaked lime to the charge1 at certain stages1 to 8stiffen it up10 the mixture could be seen to 8glow0 for a time4 ,when ,i myself saw this phenomenon1 ,i commenced to make some observations and experiments4 ,also 7as others probably had done71 ,i had observed that charges of lead with calcareous gangue are roasted more rapidly and better than others1 and to an extent which could not be wholly explained by simple physical action of the lime present4 ,simple experiments made in assay-scorifiers in a muffle1 on lime roasting1 are very striking1 and ,i think quite explain a good part of what takes place up to a certain stage in the processes now under consideration4 ,i tried them a number of years ago1 on many sorts of ore1 and again more recently1 when studying the working of the new patents4 ,for illustration1 ,i will take one class of ore 7,broken ,hill concentrate71 using a sample assaying2 ,pb1 #eh per cent42 ,fe1 #c4f per cent42 ,s1 #ad4f per cent42 ,si,o1 #c per cent4 ,the ore contained some pyrite4 ,if two scorifiers are charged1 one with the finely powdered ore alone1 and one with the ore intimately mixed with1 say1 #aj per cent4 of pure lime1 and placed side by side just within a muffle at low redness1 the limed charge will soon be seen to 8glow40 ,before the simple ore charge shows any sign of action1 the limed charge rapidly ignites all over1 like so much tinder1 and heats up considerably above the surrounding temperature1 at the same time increasing noticeably in bulk4 ,this lasts for some time1 during which hardly any ,,so passes off4 ,after the violent glowing is over1 the charge continues to calcine quietly1 giving off ,,so1 but is still far more active than its neighbor4 ,if1 finally1 the fully roasted charge is taken out1 cooled and rubbed down1 it proves to contain no free lime at all1 but large quantities of calcium sulphate can be dissolved out by boiling in distilled water4 ,for instance1 in one example where weighed quantities were taken of lime and the ore mentioned1 the final roasted material was shown to contain nearly #bc per cent4 of ,ca,s,o2 the quantity actually extracted by water was #bj4b per cent4 ,further tests show that the insoluble portion still contains calcium sulphate intimately combined with lead sulphate1 but not extractable by water4 ,there is no doubt that when lead sulphide 7or other sulphide7 is heated with lime1 with free access of air1 the lime is rapidly and completely converted into sulphate4 ,the strong base1 lime1 apparently plays the part of 8catalyzer0 in the most vigorous manner1 the first ,,so evolved being instantly oxidized and combined with the lime to sulphate1 with so strong an evolution of heat that the operation spreads rapidly and still goes on energetically1 even if the scorifier is taken out of the muffle4 ,also1 the 8catalytic0 action starts the oxidation of the sulphides at a far lower temperature than is required when they are roasted alone4 ,if1 in place of lime1 we take an equivalent weight of pure calcium carbonate and intimately mix it with ore1 we obtain just the same action1 only it takes a little longer to start it4 ,once started1 it is almost as vigorous and rapid1 and with the same results4 ,it does not seem correct to assume 7as is usually done7 that the carbonate has first to be decomposed by heat1 the lime then coming into action4 ,the reaction commences in so short a time and while the charge is still so cool1 that no appreciable driving off of ,,co by heat only can have taken place4 ,the main liberation of the ,,co occurs during the vigorous exothermic oxidation of the mixture1 and is coincident with the conversion of the ,ca,o into ,ca,s,o4 ,if1 in place of lime or its carbonate1 we use a corresponding quantity of pure calcium sulphate and mix it with the ore1 we see very energetic roasting in this case also1 with copious evolution of sulphur dioxide1 only it is much more energetic and rapid and occurs at a lower temperature than in the case of a companion charge of ore alone4 ,it is very easily demonstrated that the ,ca,s,o in contact with the still unoxidized ore 7whether it has been introduced ready made or has been formed from lime or limestone added7 greatly assists the further roasting1 in acting as a 8carrier0 and enabling calcination to take place more rapidly and easily and at a lower temperature than would otherwise be the case4 ,the result of these experiments 7whether we mix the ore with ,ca,o1 ,ca,c,o1 or ,ca,s,o7 is that we arrive with great ease and rapidity at a nearly dead-sweet roast4 ,the lime is converted into sulphate1 and the lead partly to sulphate and partly to oxide4 ,two examples out of several1 both from the above ore1 gave results as follows3 ,no4 #a--,roasted with #bj per cent4 ,ca,c,o 7 #aa4b per cent4 ,ca,o72 sulphide sulphur1 #j4jb per cent42 sulphate sulphur1 #i4cj per cent42 total sulphur1 #i4cb per cent4 ,no4 #h--,roasted with #bg4b per cent4 ,ca,s,o 7 #aa per cent4 ,ca,o72 sulphide sulphur1 #j4je per cent42 sulphate sulphur1 #aa4bh per cent42 total sulphur1 #aa4cc per cent4 ,if these calcined products are now intimately mixed with additional silica 7in about the proportions used in the ,huntington-,heberlein process7 and strongly heated1 fritting is brought about and the sulphur content is reduced by the decomposition of the sulphates by the silica4 ,thus1 the resultant material of experiment ,no4 #a1 above1 when treated in this manner with strong heat for three hours1 was sintered to a mass which was quite hard and stony when cold1 and which contained #f4ge per cent4 of total sulphur4 ,longer heating drives out more sulphur1 but a very long time is required2 in furnaces1 and on a large scale1 it is with great difficulty and cost that a product can be obtained comparable with that which is rapidly and cheaply turned out from the 8converters0 of the new process4 ,to return to the ,huntington-,heberlein process1 working1 for example1 on an ore more or less like the one given above1 we may assume that1 during the comparatively short preliminary roast1 the lime is all rapidly converted into ,ca,s,o and that some ,pb,s,o is also formed 7but not much1 as the mixture to be transferred from the furnace to the converter requires not less than #f to #h per cent4 of sulphur to be still present as sulphide1 in order that the following operation may work at its best74 ,as the blast permeates the mass1 oxidation is energetic2 no doubt that ,ca,s,o here plays a very important part as a carrier of oxygen1 in the same manner as we can see it act on a scorifier or on the hearth of a furnace4 ,what the later reactions are does not seem so clear4 ,they are quite different from those on the scorifier or on the open hearth of a furnace1 and result in the rapid formation 7in successive layers of the mixture1 from the bottom upward7 of large amounts of lead oxide1 fluxing the silica and other constituents to a more or less slaggy mass1 which decomposes the sulphates and takes up the ,ca,o into a complex and easily fused silicate4 ,it is true that1 as a whole1 the contents of a well-worked converter are never very hot1 but locally 7in the regions where the progressive reaction and decomposition from below upward is going on7 the temperature reached is considerable4 ,this formation of lead oxide is so pronounced at times that one may see in the final product considerable quantities of pure uncombined litharge4 ,when the work is successful1 the mass discharged from the converters is a basic silicate of ,pb,o1 ,ca,o1 and oxides of other metals present1 and nearly all the sulphates have disappeared4 ,a large piece of yellow product 7which was taken from a well-worked converter7 contained only #a4a per cent4 of total sulphur4 ,it may be that calcium plumbate is formed and plays a part in these reactions2 but its presence would be difficult to prove1 and its formation and existence during these stages would not be easy to explain4 ,neither does it seem necessary1 as the whole thing appears to be capable of explanation without it4 ,while the mixture in the converter is still dry and loose1 energetic oxidation of the sulphides goes on1 with the intervention of the ,ca,s,o as a carrier4 ,as soon as the heat rises sufficiently1 fluxing commences in a given layer and sulphates are decomposed4 ,the liberated sulphuric anhydride1 at the locally high temperature and under the existing conditions1 will act with the greatest possible vigor on the sulphides in the adjacent layers2 these layers will then in their turn flux and act on those above them1 till the whole charge is worked out4 ,the column of ore is of considerable hight1 requiring a blast of #a lb41 or perhaps more1 in the larger converters now used4 ,this pressure of the oxidizing blast 7and of the far more powerfully oxidizing sulphuric anhydride1 continuously being liberated within the mass of ore1 locally very hot7 constitutes a totally different set of conditions from those obtained on the hearth of a furnace with the ore in thin layers1 where it is neither so hot nor under any pressure4 ,it is to these conditions1 in which we have the continued intense action of red-hot sulphuric anhydride under a considerable pressure 7together with the earlier action of the ,ca,s,o71 that the remarkable efficiency of the process seems to me to be due4 ,in the ,carmichael process1 the preliminary roast is done away with1 ,ca,s,o being added directly instead of having to be formed during the operation from ,ca,o and the oxidized sulphur of the ore4 ,the charge in the converter has to be started by heat supplied to it1 and the work then goes forward on the same lines as in the ,huntington-,heberlein process1 so that we may assume that the reactions are the same and come under the same explanation4 ,carmichael was quick to see what was really an important part and a correct explanation of the original process4 ,he was not misled by wrong theory about any mythical calcium peroxide1 and so he obtained his patent for the use of ,ca,s,o and the dispensing of the roast in a furnace4 ,this process would always be limited in its application by the comparative rarity of cheap supplies of gypsum1 but it appears to be a great success at ,broken ,hill2 there it is not only of importance in working the leady ores1 but also for making sulphuric acid for the new treatment of mixed sulphides by the ,delprat and ,potter methods4 ,for this purpose1 the use of ,ca,s,o will have the additional advantage that the mixture to be worked in the converter will contain not only the sulphur of the ore1 but also that of the added gypsum2 on decomposition1 it will yield stronger gases for the lead chambers of the acid plant4 ,finally comes the ,savelsberg patent1 which is the simplest of all2 not only 7like the ,carmichael process7 avoiding the preliminary roast with its extra plant1 but also not requiring the use of ready-made ,ca,s,o1 as it uses raw ore and limestone directly in the converter4 ,i have no knowledge as to actual results of this process2 and1 so far as ,i am aware1 nothing on the subject has been published4 ,but ,professor ,borchers evidently has some information about it1 and regards it as the most successful of the methods of carrying out the new ideas4 ,on the face of it1 there seems no reason why it should not attain all the results desired1 as the chemical and physical actions of the ,ca,o1 and of the ,ca,s,o formed from it1 should come into play in the same manner and in the same order as in the original process2 as it is carried out in the identical converter used by ,huntington and ,heberlein1 the final reactions 7as suggested above7 will take place under the same conditions as to continuous decomposition under considerable heat and pressure1 which ,i regard as the most vital part of the whole matter4 ,it is well to emphasize again the fact that the idea1 and the means of obtaining these vital conditions1 owe their origination to ,huntington and ,heberlein4 ,,theoretical ,,aspects ,,of ,,lead-,,ore ,,roasting#bb ,,by ,c4 ,,guillemain 7,march #aj1 #aijf7 ,it is well known that the process of roasting lead ores in reverberatory furnaces proceeds in various ways according to the composition of the ore in question4 ,thus in roasting a sulphide lead ore rich in silica1 one of the reactions is3 ,pb,s #c,o ,pb,o ,,so4 ,but this reaction is incomplete1 for the gases which pass on in the furnace are rich in ,,so and in ,,so4 ,and so it is found that whatever lead oxide is formed passes over almost immediately into lead sulphate1 according to the reaction3 ,pb,o ,,so ,o ,pb,s,o4 ,this reaction is the chief one which takes place4 ,whether the silicious gangue serves as a catalyzer for the sulphur dioxide1 or whether it serves merely to keep the galena open to the action of the gases1 the end result of the roast is usually the formation of lead sulphate according to the above reaction4 ,in the case of an ore rich in galena1 a slow roast is essential1 for it is desired to have the following reaction take place during the latter part of the roast3 ,pb,s #c,pb,s,o #d,pb,o #d,,so4 ,now1 if the heating were too rapid1 not enough lead sulphate would be found to react with the unaltered galena4 ,the quick roasting of a rich ore would result in the early sintering of the charge1 and sintering prevents the further formation of lead sulphate4 ,whether this sintering 7which takes place so easily and which is so harmful in the latter part of the process7 is due to the low melting point of the lead sulphide1 whether the heat evolved by the reaction ,pb,s #c,o ,pb,o ,,so is sufficient to melt the lead sulphide1 or whether other thermochemical effects 7notably the preliminary sulphatizing of the lead sulphide7 come into play1 must for the present be undecided4 ,suffice it to say that the sintering of the charge works against a good roast4 ,in the ,tarnowitz process a definite amount of lead sulphide is converted into lead sulphate by a preliminary roast4 ,the sulphate then reacts with the unaltered lead sulphide1 and metallic lead is set free1 thus3 ,pb,s ,pb,s,o #b,pb #b,,so4 ,but when a very little of the sulphide has been transformed into sulphate1 and when there is so little of the latter present that only a small amount of lead sulphide can be reduced to metallic lead1 the mass of ore begins to sinter and grow pasty4 ,very little lead could be formed were it not for the addition of crushed lime to the charge just before the sintering begins4 ,this lime breaks up the charge and cools it1 prevents any sintering1 and allows the continued formation of lead sulphate4 ,it scarcely can be held that the lime has any chemical effect in forming lead sulphate1 or in forming a hypothetical compound of lead and calcium4 ,even if such theories were tenable from a physico-chemical point of view1 they would be lessened in importance by the fact that other substances1 such as purple ore or puddle cinder1 act just as well as the lime4 ,there are now to be mentioned several new processes of lead-ore roasting whose operations fall so far outside the common ideas on the subject that their investigation is full of interest4 ,for a long time the attempt had been made to produce lead directly by blowing air through lead sulphide in a manner analogous to the production of bessemer steel or the converting of copper matte4 ,in the case of the lead sulphide1 the oxidation of the sulphur was to furnish the heat necessary to carry on the process4 ,after many attempts along this line1 ,antonin ,germot has perfected a method wherein1 by blowing air through molten galena1 metallic lead is obtained4#bc ,about #fj per cent4 of a previously melted charge of galena is sublimed as lead sulphide1 and the rest remains behind as metallic lead4 ,the disadvantages of the process are the difficulties of collecting all of the sublimate and of working it up4 ,moreover1 it is impossible as yet to secure two products of which one is silver-free and the other silver-bearing4 ,the silver values are in both the metallic lead and in the sublimed lead sulphide4 ,while the process just described answers for pure galena1 it fails with ores which contain about #aj per cent4 of gangue4 ,in the case of such ores1 they form a non-homogeneous mass when melted1 and the blast penetrates the charge with difficulty4 ,if the pressure is increased the air forces itself out through tubes and canals which it makes for itself1 and the charge freezes around these passages4 ,messrs4 ,huntington and ,heberlein have gone a little farther4 ,although they are unable to obtain metallic lead directly1 they prepare the ore satisfactorily for smelting in the blast furnace1 after their roasting is completed4 ,the inventors found that if lead sulphide is mixed with crushed lime1 heated with access of air1 and then charged into a converter and blown1 the sulphur is completely removed in the form of sulphur dioxide4 ,the charge1 being divided by the lime1 remains open uniformly to the passage of air1 and sinters only when the sulphur is eliminated4 ,the inventors announce1 as the theory of their process1 that at #gjj deg4 ,c4 the lime forms a dioxide of calcium 7,ca,o7 which at #ejj deg4 ,c4 breaks down into lime 7,ca,o7 and nascent oxygen4 ,this nascent oxygen oxidizes the lead sulphide to lead sulphate according to the reaction3 ,pb,s #d,o ,pb,s,o4 ,furthermore it is claimed that the heat evolved by this last reaction is large enough to start and keep in operation a second reaction1 namely ,pb,s ,pb,s,o #b,pb,o #b,,so4 ,the theory1 as just mentioned1 cannot be accepted1 and some of the reasons leading to its rejection will be given4 ,it is well established that the simple heating of lime with access of air will not result in further oxidation of the calcium4 ,the dioxide of calcium cannot be formed even by heating lime to incandescence in an atmosphere of oxygen1 nor by fusing lime with potassium chlorate4 ,moreover1 calcium stands very near barium in the periodic system4 ,and as the dioxide of barium is formed at a low temperature and breaks up on continued heating1 it seems absurd to suppose that the dioxide of calcium would act in exactly the opposite manner4 ,moreover1 a consideration of the thermo-chemical effects will disclose more inconsistencies in the ideas of the inventors4 ,the breaking up of ,ca,o into ,ca,o and ,o is accompanied by the evolution of #ab cal4 ,the reaction of the oxygen 7thus supposed to be liberated7 upon the lead sulphide is strongly exothermic1 giving up #aie4d cal4 ,so much heat is produced by these two reactions that1 if the ideas of the inventors were true1 the further breaking up of the calcium dioxide would stop1 as the whole charge would be above #ejj deg4 ,c4 ,it appears1 then1 that the explanations suggested by ,messrs4 ,huntington and ,heberlein are untrue4 ,in the usual roasting process1 as carried out in reverberatory furnaces1 it is well established that the gangue1 and whatever other substances are added to the ore1 prevent mechanical locking up of charge particles1 since they stop sintering4 ,it is not at all improbable that in the new roasting process the chief1 if not the only1 part played by the lime is the same as that played by the gangue in reverberatory-furnace roasting4 ,a few observations leading to this belief will be given4 ,it is known that other substances will answer just as well as lime in this new roasting process4 ,such substances are manganese and iron oxides4 ,not only these two substances1 but in fact any substance which answers the purpose of diminishing the local strong evolution of heat1 due to the reaction3 ,pb,s #c,o ,pb,o ,,so1 serves just as well as the lime4 ,this fact is proved by exhaustive experiments in which mixtures of lead sulphide on the one hand1 and quartz1 crushed lead slags1 iron slags1 crushed iron ores1 crushed copper slags1 etc41 on the other hand1 were used for blowing4 ,all these substances are such that any chemical action1 analogous to the splitting up of ,ca,o1 or the formation of plumbates as suggested by ,dr4 ,borchers1 cannot be imagined4 ,the time is not yet ripe1 without more experiments on the subject1 to assert conclusively that there is no acceleration of the process due to the formation of plumbates through the agency of lime4 ,but the facts thus far secured point out that such reactions are1 at least1 not of much importance4 ,theoretical considerations point out that it ought to be possible to avoid the injurious local increase of temperature during the progress of this new roasting process1 without having to add any substance whatever4 ,to explain3 ,the first reaction taking place in the roasting is ,pb,s #c,o ,pb,o ,,so #ii4h cal4 ,now the heat thus liberated may be successfully dispersed if there is1 in simultaneous progress1 the endothermic reaction3 ,pb,s #c,pb,s,o #d,pb,o #d,,so - #ahg cal4 ,hence if there could be obtained a mixture of lead sulphide and of lead sulphate in the proportions demanded by the above reaction1 then such a mixture ought to be blown successfully to lead oxide without the addition of any other substance4 ,such a process has1 in fact1 been carried out4 ,the original galena is heated until the required amount of lead sulphate has been formed4 ,then the mixture of lead sulphide and of lead sulphate is transferred to a converter and blown successfully without the addition of any other substance4 ,the adaptability of an ore to the process just mentioned depends on the cost of the preliminary roast and the thoroughness with which it must be done4 ,as is known1 when lead sulphide is heated with access of air1 it is very easy to form sintered incrustations of lead sulphate4 ,if these incrustations are not broken up1 or if their formation is not prevented by diligent rabbling1 the further access of air to the mass is prevented and the oxidation of the charge stops4 ,if ores with such incrustations are placed in the converter without being crushed1 they remain unaltered by the blowing4 ,if the incrustations are too numerous the converting becomes a failure4 ,it has been found that the adoption of mechanical roasting furnaces prevents this4 ,such furnaces appear to stop the frequent failures of the blowing which are due to the lack of care on the part of the workmen during the preliminary roasting4 ,moreover1 in such mechanical furnaces a more intimate mixture of the sulphide with the sulphate is obtained1 and the degree of the sulphatizing roast is more easily controlled4 ,as a summary of the facts connected with this new blowing process1 it may be stated that the best method of working can be determined upon and adopted if one has in mind the fact that the amount of substance 7lime7 to be added is dependent on3 #a1 the amount of sulphur present2 #b1 the forms of oxidation of this sulphur2 #c1 the amount of gangue in the ore2 #d1 the specific heats of the gangue and of the substance added2 #e1 the degree of the preparatory roasting and heating4 ,for example1 with concentrates which run high in sulphur1 there is required either a large amount of additional material1 or a long preliminary roast4 ,the specific heat of the added material must be high1 and the heat evolved by the oxidation of the sulphur in the preliminary roast must be dispersed4 ,oftentimes it is necessary to cool the charge partially with water before blowing4 ,on the other hand1 if the ore runs low in sulphur1 the preliminary roast must be short1 and the temperature necessary for starting the blowing reactions must be secured by heating the charge out of contact with air4 ,not only must no flux be added1 but oftentimes some other sulphides must be supplied in order that the blowing may be carried out at all4 ,the opportunity for the acquisition of more knowledge on this subject is very great4 ,it lies in the direction of seeing whether or not the strong local evolution of heat cannot be reduced by blowing with gases poor in oxygen rather than with air4 ,mixtures of filtered flue gases and of air can be made in almost any proportion1 and such mixtures would have a marked effect upon the possibility of regulating the progress of the oxidation of the various ores and ore-mixtures which are met with in practice4 ,,metallurgical ,,behavior ,,of ,,lead ,,sulphide ,,and ,,calcium ,,sulphate#bd ,,by ,f4 ,o4 ,,doeltz 7,january #bg1 #aijf7 ,in his ,british patent1#be for desulphurizing sulphide ores1 ,a4 ,d4 ,carmichael states that a mixture of lead sulphide and calcium sulphate reacts 8at dull red heat1 say about #djj deg4 ,c410 forming lead sulphate and calcium sulphide1 according to the equation3 ,pb,s ,ca,s,o ,pb,s,o ,ca,s4 ,judging from thermo-chemical data1 this reaction does not seem probable4 ,according to ,roberts-,austen1#bf the heats of formation 7in kilogram-calories7 of the different compounds in this equation are as follows3 ,pb,s #ag4h2 ,ca,s,o #cah4d2 ,pb,s,o #baf4b2 ,ca,s #ib4 ,hence we have the algebraic sum3 -#ag4h - #cah4d #baf4b #ib -#bh4j cal4 ,as the law of maximum work does not hold1 experiment only can decide whether this decomposition takes place or not4 ,the following experiments were made3 ,experiment #a4--;,coarsely crystalline and specially pure galena was ground to powder4 ,some gypsum was powdered1 and then calcined4 ,the powdered galena and calcined gypsum were mixed in molecular proportions 7,pb,s ,ca,s,o71 and heated for #a hours to #djj deg4 ,c41 in a stream of carbon dioxide in a platinum resistance furnace4 ,the temperature was measured with a ,le ,chatelier pyrometer4 ,the material was allowed to cool in a current of carbon dioxide4 ,the mixture showed no signs of reaction4 ,under the magnifying glass the bright cube-faces of galena could be clearly distinguished4 ,if any reaction had taken place1 in accordance with the equation given above1 no bright faces of galena would have remained4 ,experiment #b4--;,a similar mixture was slowly heated1 also in the electric furnace1 to #hej deg4 ,c41 in a stream of carbon dioxide1 and was kept at this temperature for one hour4 ,it was observed that some galena sublimed without decomposition1 being redeposited at the colder end of the porcelain boat 7#g cm4 long71 in the form of small shining crystals4 ,the residue was a mixture of dark particles of galena and white particles of gypsum1 in which no evidence of any reaction was visible under the microscope4 ,that galena sublimes markedly below its melting point has already been noted by ,lodin4#bg ,experiment #c4--;,in order to determine whether the inverse reaction takes place1 for which the heat of reaction is #bh4j cal41 the following equations are given3 ,pb,s,o ,ca,s ,pb,s ,ca,s,o2 - #baf4b - #ib #ag4h #cah4d #bh4 ,a mixture of lead sulphate and calcium sulphide was heated in a porcelain crucible in a benzine-bunsen flame 7,barthel burner74 ,the materials were supplied expressly 8for scientific investigation0 by the firm1 ,c4 ,a4 ,f4 ,kahlbaum4 ,the white mixture turned dark and presently assumed the color which would correspond to its conversion into lead sulphide and calcium sulphate4 ,this experiment is easy to perform4 ,experiment #d4--,the same materials1 lead sulphate and calcium sulphide1 were mixed in molecular ratio 7,pb,s,o ,ca,s71 and were heated for #cj minutes to #djj deg4 ,c41 on a porcelain boat in the electric furnace1 in a current of carbon dioxide4 ,the mixture was allowed to cool in a stream of carbon dioxide1 and was withdrawn from the furnace the next day 7the experiment having been made in the evening74 ,the mixture showed a dark coloration1 similar to that of the last experiment2 but a few white particles were still recognizable4 ,the material in the boat smelled of hydrogen sulphide4 ,experiment #e4--;,a mixture of pure galena and calcined gypsum1 in molecular ratio 7,pb,s ,ca,s,o71 was placed on a covered scorifier and introduced into the hot muffle of a petroleum furnace1 at #gjj to #hjj deg4 ,c4 ,the temperature was then raised to #aajj deg4 ,c4 ,from #e g4 of the mixture a dark-gray porous cake weighing #c4g;g4 was thus obtained4 ,there was some undecomposed gypsum present1 recognizable under the magnifying glass4 ,no metallic lead had separated out4 ,when hot hydrochloric acid was poured over the mixture1 it evolved hydrogen sulphide4 ,the fracture of the cake showed isolated shining spots4 ,the supposition that it was melted or sublimed galena was confirmed by the aspect of the cake when cut with a knife2 the surface showed the typical appearance of the cut surface of melted galena4 ,on cutting1 the cake was found to be brittle1 with a tendency to crumble4 ,on boiling with acetic acid1 a little lead went into solution4 ,wetting with water did not change the color of the crushed cake4 ,experiment #f4--;,in his experiments for determining the melting point of galena1 ,lodin#bh found that1 in addition to its sublimation at a comparatively low temperature1 the galena also undergoes oxidation if carbon dioxide is used as the 8neutral0 atmosphere4 ,lodin was therefore compelled to use a stream of nitrogen in his determination of the melting point of galena4 ,now the temperature of experiment #b 7#hej deg4 ,c471 described heretofore1 is not as high as the melting point of galena 7which lies between #icj and #idj deg4 ,c472 therefore experiment #b was repeated in a stream of nitrogen1 so as to insure a really neutral atmosphere4 ,a mixture of galena and calcined gypsum in molecular ratio 7,pb,s ,ca,s,o7 was heated to #hej deg4 ,c41 was kept at this temperature for one hour1 and allowed to cool1 the entire operation being carried out in a stream of nitrogen4 ,again1 galena had sublimed away from the hotter end of the porcelain boat 7#f4e cm4 long71 and had been partially deposited in the form of small crystals of lead sulphide at the colder end4 ,the material in the boat consisted of a mixture of particles having the dark color of galena1 and others with the white color of gypsum1 the original crystals of gypsum and the bright surfaces of the lead sulphide being distinctly recognizable under the magnifying glass4 ,the loss in weight was #a4i per cent4 ,experiment #g4--;,for the same reason as in #b1 experiment #e was also repeated1 using a current of nitrogen4 ,a mixture of galena and calcined gypsum1 in molecular ratio 7,pb,s ,ca,s,o7 was heated in a porcelain boat to #ajcj deg4 ,c41 in a platinum-resistance furnace1 and allowed to cool1 being surrounded by a stream of nitrogen during the whole period4 ,some sublimation of lead sulphide again took place4 ,the mixture was seen to consist of white particles of gypsum1 and others dark1 like galena4 ,the loss in weight was #c4e per cent4 ,the mixture had sintered together slightly2 with hot hydrochloric acid1 it evolved hydrogen sulphide4 ,on boiling with acetic acid1 a little lead 7only a trace7 went into solution4 ,there was1 therefore1 practically no lead oxide present2 no metallic lead had separated out4 ,experiment #h4--;,in experiment #c1 lead sulphate and calcium sulphide were mixed roughly and by hand 7i4e41 not weighed out in molecular ratio72 in this experiment such a mixture of lead sulphate and calcium sulphide in molecular ratio 7,pb,s,o ,ca,s7 was heated in a porcelain crucible in a benzine-bunsen flame4 ,it presently turned dark1 and a dark gray product was obtained1 as in the former experiment4 ,experiment #i4--;,in a mixture of lead sulphate and sodium sulphide in molecular ratio 7,pb,s,o ,na,s71 the constituents react directly on rubbing together in a porcelain mortar4 ,the mass turns dark gray1 with formation of lead sulphide and sodium sulphate4 ,if a similar mixture is heated1 it also turns dark gray4 ,on lixiviation with water1 a solution is obtained which gives a dense white precipitate with barium chloride4 ,experiment #aj4--;,if lead sulphate and calcium sulphide are rubbed together in a mortar1 the mass turns a grayish-black4 ,conclusion4--,from these experiments ,i infer that the reaction ,pb,s ,ca,s,o ,pb,s,o ,ca,s does not take place1 but1 on the contrary1 that when lead sulphate and calcium sulphide are brought together1 the tendency is to form lead sulphide and calcium sulphate4 ,nevertheless1 on heating a mixture of galena and gypsum in contact with air1 lead sulphate will be formed along with lead oxide2 not1 however1 owing to any double decomposition of the galena with the gypsum1 but rather to the formation of lead sulphate from lead oxide and sulphuric acid produced by catalysis1 thus3 ,pb,o ,,so ,o ,pb,s,o4 ,this is the well-known process which always takes place in roasting galena1 the explanation of which was familiar to ,carl ,friedrich ,plattner4 ,that the presence of gypsum has any chemical influence on this process seems to be out of the question according to the above experiments4 ,,the ,,huntington-,,heberlein ,,process ,,by ,,donald ,,clark 7,october #bj1 #aijd7 ,the process was patented in #ahig1 and is based on the fact that galena can be desulphurized by mixing it with lime and blowing a current of air through the mixture4 ,if the temperature is dull red at the start1 no additional source of heat is necessary1 because the reaction causes a great rise in temperature4 ,the chemistry of the process cannot be said at present to have been worked out in detail4 ,the reactions given by the patentees are not satisfactory1 since calcium dioxide is formed only at low temperatures and is readily decomposed on gently warming it2 lead oxide1 however1 combines with oxygen under suitable conditions at a temperature not exceeding #dej deg4 ,c4 and forms a higher oxide1 and it is probable that this unites with the lime to form calcium plumbate4 ,the reaction between sulphides and lime when intimately mixed and heated may be put down as ,ca,o ,pb,s ,ca,s ,pb,o4 ,in contact with the air the calcium sulphide oxidizes to sulphite1 then to sulphate1 then reacts with lead oxide1 giving calcium plumbate and sulphur dioxide1 ,ca,s,o ,pb,o ,ca,pb,o ,,so4 ,further1 calcium sulphate will also react with galena1 giving calcium sulphide and lead sulphate2 the calcium sulphide is oxidized1 by air blown through1 to calcium sulphate again1 the ultimate reaction being ,ca,s,o ,pb,s ,o ,ca,pb,o ,,so4 ,in all cases the action is oxidizing and desulphurizing4 ,it was found that oxides of iron and manganese will1 to a certain extent1 serve the same purpose as lime1 and on application to complex ores1 especially those containing much blende1 that these may be desulphurized as well as galena4 ,in the case of zinc sulphide the decomposition is probably due to the interaction of sulphide and sulphate4 ,zn,s #c,zn,s,o #d,zn,o #d,,so4 ,the process has now been adopted by the ,broken ,hill ,proprietary ,company at its works at ,port ,pirie1 the ,tasmanian ,smelting ,company1 ,zeehan1 the ,fremantle ,smelting ,works1 ,west ,australia1 and the ,sulphide ,corporation's works at ,cockle ,creek1 ,new ,south ,wales4 ,the operations carried on at the ,tasmania ,smelting ,works comprise mixing pulverized limestone1 galena and slag-making materials and introducing the mixture either into hand-rabbled reverberatories or mechanical furnaces with rotating hearths4 ,after a roast1 during which the materials have become well mixed and most of the limestone converted into sulphate and about half of the sulphur expelled1 the granular product is run while still hot into the ,huntington-,heberlein converters4 ,these consist of inverted sheet-iron cones1 hung on trunnions1 the diameter being #e ft4 #f in4 and the depth #e ft4 ,a perforated plate or colander is placed as a diaphragm across the apex of the cone1 the small conical space below serving as a wind-box into which compressed air is forced4 ,a hood above the converter serves to carry away waste gases4 ,as soon as the vessel is filled1 air under a pressure of #ag oz4 is forced through the mass1 which rapidly warms up1 giving off sulphur dioxide abundantly4 ,the temperature rises and the mixture fuses1 and in from two to four hours the action is complete4 ,the sulphur is reduced from #aj to #a per cent41 and the whole mass is fritted and fused together4 ,the converter is emptied by inverting it1 when the sintered mass falls out and is broken up and sent to the smelters4 ,there are #ab converters1 of the size indicated1 for the two mechanical furnaces1 of #ae ft4 diameter4 ,larger converters of the same type were erected to deal with the product from the hand-rabbled roasters4 ,at ,cockle ,creek1 ,new ,south ,wales1 the galena concentrate is reduced to #a4e mm41 more than #fj per cent4 of the material being finer2 the limestone is crushed down to from #aj to #af mesh2 silica is also added1 if it does not exist in the ore1 so that1 excluding the lead1 the rest of the bases will be in such proportion as to form a slag running about #bj per cent4 silica4 ,the mixture may contain from #be to #ej per cent4 lead1 and from #f to #i per cent4 lime2 if too much lime is added the final product is powdery1 instead of being in a fused condition4 ,this is given a preliminary roast in a ,godfrey furnace4 ,the ,godfrey furnace is characterized by a rotating1 circular hearth and a low dome-shaped roof4 ,ore is fed through a hopper at the center and deflected outward by blades attached to a fixed radial arm4 ,at each revolution the ore is turned over and moved outward1 the mount of deflection of the blades1 which are adjustable1 and rate of rotation of the hearth1 determining the output4 ,the hot semi-roasted ore is discharged through a slot at the circumference of the roaster4 ,this may contain from #ab to #f4e per cent4 of sulphur1 but from #f4e to #h per cent4 is held to be the most suitable quantity for the subsequent operations4 ,thorough mixing is of the utmost importance1 for if this is not done the mass will 8volcano0 in the converter2 that is1 channels will form in the mass through which the gases will escape1 leaving lumps of untouched material alongside4 ,the action can be started if a little red-hot ore is run into the converter and cold ore placed above it2 the whole mass will become heated up1 and the products will fuse1 and sinter into a homogeneous mass showing none of the original ingredients4 ,at ,cockle ,creek the time taken is stated to be five hours2 a small air-pressure is turned on at first1 and ultimately it is increased to #bj oz4 ,operations at ,port ,pirie are conducted on a much larger scale4 ,a mixture of pulverized galena1 powdery limestone1 ironstone and sand is fed into ,ropp furnaces1 of which there are five1 by means of a fluted roll placed at the base of a hopper4 ,each roaster deals with #ajj tons of the mixture in #bd hours4 ,about #ej per cent4 of the sulphur is eliminated from the ore by the ,ropps 7the galena in this case being admixed with a large amount of blende1 there being only #ee per cent4 of lead and #aj per cent4 of zinc in the concentrate produced at the ,proprietary mine74 ,the hot ore from the roasters is trucked to the converters1 there being #ag of these ranged in line4 ,the converters here are large segmental cast-iron pots hung on trunnions2 each is about #h ft4 diameter and #f ft4 deep1 and holds an #h-ton charge4 ,at about two feet from the bottom an annular perforated plate fits horizontally2 a shallow frustrum of a cone1 also perforated1 rests on this2 while a plate with a few perforations closes the top of the frustrum4 ,the whole serves as a wind-box4 ,a conical hood with flanged edges rests on the flanged edges of the converter1 giving a close joint4 ,this hood is provided with doors which allow the charge to be barred if necessary4 ,a pipe about #a ft4 #i in4 diameter1 fitted with a telescopic sliding arrangement1 allows for the raising or lowering of the hood by block and tackle1 and thus enables the converter to be tilted up and its products emptied4 ,the cast-iron pots stand very well2 they crack sometimes1 but they can be patched up with an iron strap and rivets4 ,only two pots have been lost in #ah months4 ,air enters at a pressure of about #bd oz4 and the time taken for conversion is about four hours4 ,the sulphur contents are reduced to about three per cent4 ,it is found that the top of the charge is not so well converted as the interior4 ,there is practically no loss of lead or silver due to volatilization and very little due to escape of zinc4 ,it has also been found that practically all the limestone fed into the ,ropp is converted into calcium sulphate2 also that a considerable portion of lead becomes sulphate1 and it is considered that lead sulphate is as necessary for the process as galena4 ,the value of the process may be judged from the fact that better work is now done with #h blast furnaces than was done with #ac before the process was adopted4 ,in addition to the sintered product from the ,huntington-,heberlein pots1 sintered slime1 obtained by heap roasting1 and flux consisting of limestone and ironstone1 are fed into the furnaces1 which take #bjjj long tons per day of ore1 fluxes and fuel4 ,the slags now being produced average3 ,si,o1 #be to #bf per cent42 ,fe,o1 #a to #c per cent42 ,mn,o1 #e to #e4e2 ,ca,o1 #ae4e to #ag2 ,zn,o1 #ac2 ,al,o1 #f4e2 ,s1 #c to #d2 ,pb1 by wet assay1 #a4b to #a4e per cent42 and ,ag1 #j4g oz4 per ton4 ,although this comparatively large quantity of sulphur remains1 yet no matte is formed4 ,,the ,,huntington-,,heberlein ,,process ,,at ,,friedrichsh,,tte#bi ,,by ,a4 ,,biernbaum 7,september #b1 #aije7 ,nothing1 for some time past1 has caused such a stir in the metallurgical treatment of lead ores1 and produced such radical changes at many lead smelting works1 as the introduction of the ,huntington-,heberlein process4 ,this process 7which it may be remarked1 incidentally1 has given rise to the invention of several similar processes7 represents an important advance in lead smelting1 and1 now that it has been in use for some time at the ,friedrichshtte1 near ,tarnowitz1 in ,upper ,silesia1 and has there undergone further improvement in several respects1 a comparison of this process with the earlier roasting process is of interest4 ,at the above-mentioned works1 up to #aijj the lead ore was treated exclusively 7#a7 by smelting in reverberatory furnaces 7,tarnowitzerfen71 and 7#b7 by roasting in reverberatory-sintering furnaces roasted material in the shaft furnace4 ,the factor which determined whether the treatment was to be effected in the reverberatory-smelting or in the roasting-sintering furnace was the percentage of lead and zinc in the ores2 those comparatively rich in lead and poor in zinc being worked up in the former1 with partial production of pig-lead2 while those poorer in lead and richer in zinc were treated in the latter4 ,about two-fifths of the lead ores annually worked up were charged into the reverberatory-smelting furnaces1 and three-fifths into the sintering furnaces4 ,in #aijj there were available #aj reverberatory-smelting and nine sintering furnaces4 ,these were worked exclusively by hand4 ,the sintered product of the roasting furnaces1 and the gray slag from the reverberatory-smelting furnaces1 were transferred to the shaft furnaces for further treatment1 and were therein smelted together with the requisite fluxes4 ,eight such furnaces 7#h m4 high1 and #a4d m41 #a4f m41 and #a4h m4 respectively in diameter at the tuyeres71 partly with three and partly with five or eight tuyeres1 were at that time in use4 ,now that the ,huntington-,heberlein process has been completely installed1 the reverberatory-smelting furnaces have been shut down entirely1 and the sintering furnaces also for the most part2 all kinds of lead ore1 with a single exception1 are worked up by the ,huntington-,heberlein process1 irrespective of the contents of lead and zinc4 ,an exceedingly small proportion of the ore treated1 viz41 the low-grade concentrate 7,herdschlieche7 containing #be to #ce per cent4 ,pb1 is still roasted in the old sintering furnace1 together with various between-products 7such as dust1 fume1 scaffoldings1 and matte72 these are scorified by the aid of the high percentage of silica in the material4 ,for roasting lead ores at the present time there are six round mechanical roasters of #f m4 diameter1 one of #h m4 diameter1 and two ordinary1 stationary ,huntington-,heberlein furnaces4 ,the latter 7which represent the primitive ,huntington-,heberlein furnaces1 requiring manual labor7 have recently been shut down1 and will probably never be used again4 ,in the mechanical ,huntington-,heberlein furnace1 roasting of lead ore is carried only to such a point that a small portion of the lead sulphide is converted into sulphate4 ,the desulphurization of the ore is completed in the so-called converter 7made of iron1 pear-shaped or hemispherical in form7 in which the charge1 up to this stage loosely mixed1 is blown to a solid mass4 ,owing to the ready fusibility of this product 7which still contains1 as a rule1 up to #a4e per cent4 sulphur as sulphide71 it is possible to use shaft furnaces of rather large dimensions2 therefore a round shaft furnace 7#b4d m4 diameter at the tuyeres1 #g m4 high1 and furnished with #ae tuyeres7 was built4 ,in this furnace nearly the whole of the roasted ore from the ,huntington-,heberlein converters is now smelted1 some of the smaller shaft furnaces being used occasionally4 ,the introduction of the new process has caused no noteworthy change in the subsequent treatment of the work-lead4 ,in the following study ,i shall discuss the treatment of a given annual quantity of ore 7#ej1jjj tons71 which is the actual figure at the ,friedrichshtte at the present time4 #a4 ,roasting ,furnaces4--,a reverberatory-smelting furnace used to treat #e tons of ore in #bd hours2 a roasting-sintering furnace1 #h tons4 ,assuming the ratios previously stated1 the annual treatment by the former process would be #bj1jjj tons1 and by the latter #cj1jjj tons4 ,on the basis of #cjj working days per year1 and no prolonged stoppages for furnace repairs 7though considering the high temperatures of these furnaces this record would hardly be expected71 there would be required3 #bj1jjj 7#e #cjj7 #ac4c 7or #ac to #ad reverberatory furnaces74 #cj1jjj 7#h #cjj7 #ab4e 7or #ab to #ac sintering furnaces74 ,the capacity of a stationary ,huntington-,heberlein furnace is #ah tons2 hence in order to treat the same quantity of ores there would be required3 #ej1jjj 7#ah #cjj7 #i4c 7or #i to #aj ,huntington-,heberlein furnaces74 ,with the revolving-hearth roasters 7of #f m4 diameter7 working a total charge of at least #bg tons of ore1 there would be required3 #ej1jjj 7#bg #cjj7 #f4a 7or #f to #g roasters74 ,still better results are obtained with the #h m4 round roaster1 which has been in operation for some time2 in this1 #ee tons of ore can be roasted daily4 ,three such furnaces would therefore suffice for working up the whole of the ore charged per annum4 ,now1 making due provision for reserve furnaces1 to work up #ej1jjj tons of ore would require3 ,reverberatory 7#ae7 and sintering furnaces 7#ae7 #cj ,stationary ,huntington-,heberlein furnaces #ab #f m4 revolving-hearth furnaces #h #h m4 revolving-hearth furnaces #d ,similar relations hold good regarding the number of workmen attending the furnaces1 there being required1 daily1 six men for the reverberatory furnace2 eight men for the sintering furnace2 ten men for the stationary2 and six men for the mechanical ,huntington-,heberlein furnace2 or1 for #ad reverberatory furnaces1 daily1 #hd men2 for sintering furnaces1 daily1 #ajd men2 total1 #ahh men4 ,while for #aj stationary ,huntington-,heberlein furnaces1 #ajj men are required2 and for #g mechanical ,huntington-,heberlein furnaces1 daily1 #db men4 ,it is expected that only #ad men 7working in two shifts7 will be required to run the new installation with #h m4 round roasters4 ,it is true that the exclusion of human labor here has been carried to an extreme4 ,the roasters and converters will be charged exclusively by mechanical means2 thus every contact of the workmen with the lead-containing material is avoided until the treatment of the roasted material in the converters is completed4 ,from the data given above1 the capacity of each individual workman is readily determined1 as follows3 ,with the reverberatory-smelting furnace1 each man daily works up #j4hc tons2 with the sintering furnace1 #a ton2 with the stationary ,huntington-,heberlein furnace1 #a4h tons2 with the #f m4 revolving-hearth furnace1 #d4e tons2 and with the #h m4 revolving-hearth furnace1 #aa4h tons4 ,a significant change has also taken place in coal consumption4 ,thus1 when working with the reverberatory and sintering furnaces in order to attain the requisite temperature of #ajjj deg4 ,c41 there was required not only a comparatively high-grade coal1 but also a large quantity of it4 ,a reverberatory furnace consumed about #ejc kg41 a sintering furnace about #bhg kg41 of coal per ton of ore4 ,for roasting the ore in the stationary and also in the mechanical ,huntington-,heberlein furnaces1 a lower temperature 7at most #gjj deg4 ,c47 is sufficient1 as the roasting proper of the ore is effected in the converters1 and the sulphur furnishes the actual fuel4 ,for this reason1 the consumption of coal is much lower4 ,the comparative figures per ton of ore are as follows3 ,in the reverberatory furnace1 #ej4c per cent42 in the sintering furnace1 #bh4g per cent42 in the stationary ,huntington-,heberlein furnace1 #aj4c per cent42 and in the ,huntington-,heberlein revolving-hearth furnace1 #g4c per cent4 ,but there is another technical advantage of the ,huntington-,heberlein process which should be mentioned4 ,it is well known that the volatilization of lead at high temperatures is an exceedingly troublesome factor in the running of a lead-smelting plant2 the recovery of the valuable fume is difficult1 and requires condensing apparatus1 to say nothing of the unhealthful character of the volatile lead compounds4 ,this volatilization is of course particularly marked at the high temperatures employed when working with reverberatory-smelting furnaces2 the same is true1 in a somewhat less degree1 of the sintering furnaces4 ,in consequence of the markedly lower temperature to which the charge is heated in the ,huntington-,heberlein furnace1 and also of the peculiar mode of completing the roast in blast-converters1 the production of fume is so reduced that the difference between the values recovered in the old and the new processes is very striking4 ,whereas1 in #aijj1 in working up #ab1ibb tons of ore in the reverberatory-smelting furnace1 and #ad1dig tons in the sintering furnace 7#bg1dai tons in all71 there was recovered #bdgj tons 7or #i per cent47 as fume from the condensers and smoke flues1 the quantity of fume recovered1 in #aijc1 fell to #hgi tons 7or #a4h per cent471 out of the #dh1bjh tons of ore roasted1 and this notwithstanding the fact that in the meantime fume-condensing appliances had been considerably expanded and improved1 whereby the collection was much more efficient4 ,lastly1 the zinc content of the ores no longer exerts the same unfavorable influence as in the old process 7wherein it was advisable to subject ore containing much blende to a final washing before proceeding to the actual metallurgical treatment74 ,in the new process1 the ores are simply roasted without regard to their zinc content4 ,in this connection it has been found that a considerable proportion of the zinc passes off with the fume1 and that the roasted material usually contains a quantity of zinc so small that it no longer causes any trouble in the shaft furnace4 ,it may also be mentioned here that the ore-dressing plants recently installed in the mines of ,upper ,silesia have resulted in a more perfect separation of the blende4 ,shaft ,furnaces4--,the finished product from the ,huntington-,heberlein blast-converters is of a porous character1 and already contains a part of the flux materials 7such as limestone1 silica and iron7 which are required for the shaft-furnace charge4 ,it is just these two characteristics of the roasted product 7its porous nature1 on the one hand1 leading to its more perfect reduction by the furnace gases2 and1 on the other hand1 the admixture of fluxes in the molten condition1 resulting in a more complete utilization of the temperature71 which1 together with its higher lead and lower zinc content1 determine its ready fusibility4 ,if we further consider that it is possible in the new process to make the total charge of the shaft furnace richer in lead than formerly 7two-thirds of the total charge as against one-third71 and that a higher blast pressure can be used without danger1 it follows immediately that the capacity of a shaft furnace is much greater by the new process than by the old method of working4 ,the daily production of the shaft furnaces on the old and the new process is as shown in the table given herewith3 ,,charge ,,work-,,lead ,,type ,,of ,,shaft ,,character ,,of ,,charge ,,per ,,day1 ,,produced ,,furnace ,,tons ,,per ,,day1 ,,tons #c tuyeres ,gray slag from #cf #f to #g reverberatory furnaces and ,low- sintered concentrate pressure ,blast #h tuyeres 0 0 #cf to #ch #f to #h #c tuyeres ,roasted product of #cf #aa to #ab ,huntington-,heberlein process #h tuyeres 0 0 #fe to #gb #bd to #bf ,high- pressure #ae tuyeres 0 0 #bgj #ij to #ajj ,blast ,it should be noted that the figure given for the furnace with #ae tuyeres represents the average for #aijd2 this average is lowered by the circumstance that during this period there was frequently a deficiency of roasted material1 and the furnace had to work with low-pressure blast4 ,a truer impression can be gained from the month of ,march1 #aije1 for instance1 during which time this furnace worked under normal conditions2 the results are as follows3 ,the average for ,march1 #aije1 was3 ,ore charged1 #h1bfi4gae tons2 coke1 #feb4dda tons2 total1 #h1ibb4aef tons4 ,or1 in #bd hours3 ,ore charged1 #bff4gfe tons2 coke1 #ba4jdf tons2 total1 #bhg4haa tons4 ,the production of work-lead was #c1acc4bde tons1 or #aja4jfi tons per day4 ,the maximum production of roasted ore was #baj tons1 on ,june #cj1 #aije1 when the total charge was3 ,ore1 #cbg4ch tons2 coke1 #be4b tons2 total1 #ceb4eh tons4 ,the quantity of work-lead produced on that day was #abj4fie tons1 while the largest quantity previously produced in one day was #abd4hf tons4 ,it should also be mentioned that the lead tenor of the slag is almost invariably below #a per cent42 it usually lies between #j4c and #j4e per cent4 ,as in the case of the roasting furnaces1 the productive capacity of the shaft furnace also comes out clearly if we figure the number of furnaces required1 on the basis of an annual consumption of #ej1jjj tons of ore4 ,if we consider #a ton of the roasted material as equivalent to #a ton of ore 7which is about right in the case of the ,huntington-,heberlein material1 but is rather a high estimate in the case of the product of the sintering furnace71 then1 in the old process 7where one-third of the charge was lead-bearing material71 #ab tons could be smelted daily4 ,there would therefore be needed at least3 #ej1jjj 7#ab #cjj7 #ad three-tuyere shaft furnaces4 ,since1 as already mentioned1 the lead-bearing part of the charge constitutes two-thirds of the whole in the ,huntington-,heberlein process1 the number of shaft furnaces of different types1 as compared with the foregoing1 would figure out3 #c-tuyere shaft furnace1 with product of sintering furnace1 #ej1jjj 7#ab #cjj7 #ad furnaces2 #c-tuyere shaft furnace1 with product of ,huntington-,heberlein furnace1 #ej1jjj 7#bd #cjj7 #g furnaces2 #h-tuyere shaft furnace1 with product of ,huntington-,heberlein furnace1 #ej1jjj 7#dh #cjj7 #c4d 7say #d7 furnaces2 #ae-tuyere shaft furnace1 with product of ,huntington-,heberlein furnace1 #ej1jjj 7#ahj #cjj7 #a furnace4 ,running regularly and without interruption1 the large shaft furnace is therefore fully capable of coping with the ,huntington-,heberlein roasted material at the present rate of production4 ,as regards the number of workmen and the product turned out per man1 no such marked difference is produced by the introduction of the ,huntington-,heberlein process in the case of the shaft furnace as there was noted for the roasting operation4 ,this is chiefly due to the fact that the work which requires the more power 7such as charging of the furnaces1 conveying away the slag and pouring the lead7 can be executed only in part by mechanical means4 ,nevertheless1 it will be seen from the table given herewith that1 on the one hand1 the number of men required for the charge worked up is smaller2 and1 on the other1 the product turned out per man has risen somewhat4 ,,type ,,of ,,character ,,charge ,,number ,,of ,,charge ,,daily ,,output ,,output ,,shaft ,,of ,,charge,,per ,,day1,,furnacemen,,per ,,man1,,of ,,work-,,lead1,,per ,,man1 ,,furnace ,,tons ,,tons ,,tons ,,tons #c tuyere ,a #cf #f #f4j #f #a4j #h tuyere ,b #ch #f #f4c #h #a4c #c tuyere ,c #cf #f #f4j #ab #b4j #h tuyere ,d #gb #ab #f4j #bf #b4a #ae tuyere ,e #bgj #cd #g4i #ij #b4f ,,character ,,character ,,of ,,charge ,,of ,,charge ,,code ,a ,sintered concentrate and gray slag ,b from reverberatory furnace4 ,b ,gray slag from reverberatory furnace4 ,c ,huntington-,heberlein product4 ,d ,huntington-,heberlein product4 ,e ,huntington-,heberlein product4 ,a slight difference only is produced by the new process in the consumption of coke2 the economy is a little over #a per cent41 the coke consumed being reduced from #i4ci per cent4 to #h4ag per cent4 of the total charge4 ,but with the high price of coke1 even this small difference represents a considerable lowering of the cost of production4 ,with the great increase in the blast pressure1 it would be supposed that the losses in fume would be much greater than with the former method of working4 ,but this is not the case2 on the contrary1 all experience so far shows that there is much less fume developed4 ,in #aijd1 for instance1 the shaft-furnace fume recovered in the condensing system amounted to only #a4jf per cent4 of the roasted material1 or #j4fd per cent4 of the total charge1 as against #b4jc and #a4j per cent41 respectively1 in former years4 ,the observations made on the quantity of flue dust carried away with the gases escaping into the air through the stack showed that it is almost nil4 ,now1 from the loss in fume being slight1 from the tenor of lead in the slag being low1 and1 on the one hand1 from the quantity of lead-matte produced being much less than before1 while on the other the losses in roasting the ore are greatly reduced--from all these considerations1 it is clear that the total yield must have been much improved4 ,as a matter of fact1 the yield of lead and silver has been increased by at least #f to #h per cent4 ,economic ,results4--,as regards the economical value of the new process1 for obvious reasons no data can be furnished of the exact expenditure1 i4e41 the actual total cost of roasting and smelting the ore4 ,but this at least is placed beyond doubt by what has been developed above1 namely1 that considerable saving must be effected in the roasting1 and especially in the smelting1 as compared with the former mode of working4 ,if we take into account only the economy which is gained in wages through the increase in the material which one workman can handle1 and that resulting from the reduced consumption of coal and coke1 these alone will show sufficiently that an important diminution of working cost has taken place4 ,the objection which might be raised1 that the saving effected by reducing manual labor may be neutralized by the expense of mechanical power 7actuating the roasters1 furnishing the compressed blast1 etc471 cannot be regarded as justified1 as the cost of mechanical work is comparatively low4 ,thus1 for instance1 the large #h m4 furnace and the small1 round furnaces require #ae h4p4 if worked by electricity4 ,according to an exact calculation1 the cost 7to the producer7 of the h4p4 hour1 inclusive of machinery1 figures out to #c4f pfennigs 7#j4i;c472 hence the daily expense for running the revolving-hearth furnaces amounts to3 #ae #c4f pfg4 #bd #ab4if marks 7#c4db74 ,as the seven furnaces together work up3 7#f #bg7 #ee #bag tons of ore1 the cost per ton of ore is about #j4jf mark 7#a4e;c474 ,the requisite blast is produced by means of single-compression ,encke blowers1 of which one is quite sufficient when running at full load1 and then consumes #cd h4p4 ,the daily expenses are accordingly3 #cd #c4f pfg4 #bd #bi4bh marks 7#g4cb72 or per ton of ore1 #bi4bh #bag #j4ad mark 7#c4e;c474 ,therefore the total expense for the mechanical work in roasting the ore amounts to #j4jf #j4ad #j4bj mark 7#e;c474 ,however1 the cost of roasting is much more affected by the expense for keeping the furnaces in repair2 another important factor is the acquisition and maintenance of the tools4 ,both in the case of the sintering and also the reverberatory-smelting furnace1 the cost of keeping in repair was high2 the consumption of iron was especially large1 owing to the rapid wear of the tools4 ,this was not surprising1 considering that a notably higher temperature prevailed in the reverberatory and sintering furnaces than in the new roasters1 in which the temperature strictly ought not to rise above #gjj deg4 ,c4 ,but in the old type of furnace the high temperature and the constant working with the iron tools caused their rapid wear1 thus creating a large item for iron and steel and smith work4 ,in the new process 7and more especially in the revolving-hearth roasters7 this disadvantage does not arise4 ,in this case there is practically no work on the furnace1 and the wear and tear of iron is small4 ,also1 the cost of keeping the furnaces in repair when working regularly is small as compared with the old process4 ,in the year #aijj1 for instance1 the cost of maintenance and tools for the reverberatory and sintering furnaces came to #bj1gja4ic marks 7#e1age4dh7 for treating #bg1dai4ge tons of ore4 ,per ton of ore1 this represents #j4ge mark 7#ai;c474 ,in the year #aijc1 on the other hand1 only #i1jgd4ag marks 7#b1bfh4ed7 were expended1 although #dh1bjh tons of ore were worked up in the three stationary and six mechanical ,huntington-,heberlein furnaces4 ,the cost of maintenance was1 therefore1 in this case #j4ah mark 7#d4e;c47 per ton of ore4 ,in the cost of smelting in the shaft furnace1 only a slight difference in favor of the ,huntington-,heberlein process is found if the estimate is based on the total charge2 but a marked difference is shown if it is referred to the lead-bearing portion of the charge1 or to the work-lead produced4 ,thus the cost of maintenance and total cost of smelting1 figured for one ton of ore1 without taking into account general expenses1 have been tabulated as follows3 ,,reduction ,,in ,,expenses ,,per ,,ton ,,of ,,total ,,lead ,,ore ,,work-,,lead ,,charge 7a7 ,cost of maintenance #j4ja,m #j4ch,m #j4fg,m 7#j4be;c7 7#i4e;c7 7#af4ge;c7 7b7 ,total cost of smelting #j4bj,m #f4df,m #aa4dh,m 7#e;c7 7#a4fae7 7#b4hg7 ,the marked reduction in the expenses1 as referred to the lead-ore and the work-lead produced1 is determined 7as was pointed out above7 by the greater lead content of the charge1 and by the larger yield of lead consequent thereon4 ,the advantage of longer smelting campaigns 7which ultimately were mostly prolonged to one year7 also makes itself felt2 it would be still more marked1 if the shaft furnace 7which was still in working condition after it was blown out7 had been run on for some time longer4 ,finally1 if we examine the question of the space taken up by the plant 7which1 owing to the scarcity of suitably located building sites1 would have been important at the ,friedrichshtte at the time when the quantity of ore treated was suddenly doubled71 here again we shall recognize the great advantage which this establishment has gained from the ,huntington-,heberlein process4 ,as was calculated above1 there would have been required #ae reverberatory and #ae sintering furnaces to cope with the quantity of ore treated4 ,as a reverberatory requires1 in round numbers1 #abj sq4 m4 7#abij sq4 ft471 and a sintering furnace #bjj sq4 m4 7#baec sq4 ft472 and as fully #ajj sq4 m4 7#ajhj sq4 ft47 must be allowed for each furnace for a dumping ground1 therefore the #ae reverberatory furnaces would have required an area of #ae #abj #ae #ajj #ccjj sq4 m42 the #ae sintering furnaces would have required #ae #bjj #ae #ajj #dejj sq4 m42 in all #ccjj #dejj #ghjj sq4 m4 7#hc1ifj sq4 ft474 ,the #ab stationary ,huntington-,heberlein furnaces 7built together two and two7 would take up a space of #f #bjj #ab #ajj #bdjj sq4 m4 7#be1hcj sq4 ft474 ,similarly1 #h small furnaces would require #h #ajj #h #ajj #afjj sq4 m4 7#ag1bbb sq4 ft472 while for the new installation of four #h-meter revolving-hearth furnaces and #aj large converters1 only #acbj sq4 m4 7#ad1abj sq4 ft47 have been allowed4 ,for shaft furnaces with three or eight tuyeres1 which were run with low-pressure blast for the material roasted on the old plan1 the total area built upon was #ah #af4e #big sq4 m42 while a further area of #ah #ad #bej sq4 m4 was hitherto provided1 and was found sufficient for dumping slag when working regularly4 ,therefore1 the installation of shaft furnaces formerly in existence1 after requisite enlargement to #ad furnaces1 would have demanded a space of #g #big #g #bej #chbi sq4 m4 7#db1bae sq4 ft474 ,if four of the small shaft furnaces had been reconstructed for eight tuyeres1 and run with ,huntington-,heberlein roasted material1 using high-pressure blast1 the area occupied would have been reduced to #b #big #b #bej sq4 m4 #ajid sq4 m4 7#aa1ggf sq4 ft474 ,still more favorable are the conditions of area required in the case of the large shaft furnace4 ,this furnace stands in a building covering an area of #cej sq4 m4 7#cgfg sq4 ft471 which is more than sufficient room4 ,the slag-yard 7situated in front of this building1 and amply large enough for #cf hours' run7 has an area of #bej sq4 m4 7#bfia sq4 ft472 thus the space occupied by the large shaft furnace1 including a yard of #agj sq4 m4 7#ahcj sq4 ft471 is in all #ghj sq4 m4 7#hcif sq4 ft474 ,after completion of the new roasting plant and the large shaft furnace in connection with it1 there would be occupied #acbj #ghj #bajj sq4 m4 7#bbfj sq4 ft472 and if the system of reverberatory and sintering furnaces had been continued 7with the requisite additions thereto and to the old shaft-furnace system71 there would have been required #aa1fbi sq4 m4 7#abe1bad sq4 ft474 ,in the estimate above given no regard has been paid to any of the auxiliary installations 7dust chambers1 etc471 which1 just as in the case of the old process1 would have had to be provided on a large scale4 ,it is of course self-evident that both the principal and the auxiliary installations in the old process would not only have involved a high first cost1 but would also1 on account of their extensive dimensions1 have caused considerably greater annual expense for maintenance4 ,,the ,,huntington-,,heberlein ,,process ,,from ,,the ,,hygienic ,,standpoint#cj ,,by ,a4 ,,biernbaum 7,october #ad1 #aije7 ,with regard to the hygienic improvements which the ,huntington-,heberlein process offers1 we must first deal with the questions3 ,what were the sources of danger in the old process1 and in what way are these now diminished or eliminated8 ,the only danger which enters into consideration is lead-poisoning1 other influences detrimental to health being the same in one process as the other4 ,with the reverberatory-smelting and roasting-sintering furnaces1 the chief danger of lead-poisoning lies in the metallic vapor evolved during the withdrawal of the roasted charge from the furnace4 ,it is true that appliances may be provided1 by which these vapors are drawn off or led back into the furnace during this operation2 but1 even working with utmost care1 it is impossible to insure the complete elimination of lead fumes1 especially in wheeling away the pots filled with the red-hot sintered product4 ,moreover1 the work at the reverberatory-smelting and roasting-sintering furnaces involves great physical exertion1 wherefore the respiratory organs of the workmen are stimulated to full activity1 while the exposure to the intense heat causes the men to perspire freely4 ,hence1 as has been established medically1 the absorption of the poisonous metallic compounds 7which are partially soluble in the perspiration7 into the system is favored both by inhalation of the lead vapor and by its penetration into the pores of the skin1 opened by the perspiration4 ,a further danger of lead-poisoning was occasioned by the frequently recurring work of clearing out the dust flues4 ,the smoke from the reverberatory-smelting furnace especially contained oxidized lead compounds1 which on absorption into the human body might readily be dissolved by the acids of the stomach1 and thus endanger the health of the workmen4 ,in the ,huntington-,heberlein furnaces1 on the other hand1 although the charge is raked forward and turned over by hand1 it is not withdrawn1 as in the old furnaces1 by an opening situated next to the fire1 but is emptied at a point opposite into the converters which are placed in front of the furnace4 ,moreover1 the converters are filled with the charge at a much lower temperature4 ,inasmuch as this charge has already cooled down considerably1 there can be practically no volatilization of lead4 ,the small quantity of gas which may nevertheless be evolved is drawn off by fans through hoods placed above the converters4 ,a further improvement1 from the hygienic point of view1 is in the use of the mechanical furnaces1 from which the converters can be filled automatically 7almost without manual labor1 and with absolute exclusion of smoke74 ,the converters are then placed on their stands and blown4 ,this work also is carried out under hoods1 as gas-tight as possible1 furnished with a few closable working apertures4 ,during the blowing of the material1 the work of the attendant consists solely in keeping up the charge by adding more cold material and filling any holes that may be formed4 ,it does not entail nearly as much physical strain as the handling of the heavy iron tools and the continued exposure of the workmen to the hottest part of the furnace1 which the former roasting process involved4 ,some experiments carried out with larger converters 7of #d and #aj ton capacity7 have indicated the direction in which the advantages mentioned above may probably be developed to such a point that the danger of lead-poisoning need hardly enter into consideration4 ,both the charging of the revolving-hearth furnaces and the filling of the converters are to be effected mechanically4 ,furthermore1 in the case of the large converters the filling up of holes becomes unnecessary1 and no manual work of any kind is required during the whole time of blowing4 ,the converters can be so perfectly enclosed in hoods that the escape of gases into the working-rooms becomes impossible1 and lead-poisoning of the men can occur only under quite unusual circumstances4 ,the beneficial influence on the health of the workmen attending on the roasting furnaces1 occasioned by the introduction of the ,huntington-,heberlein process1 can be seen from the statistics of sickness from lead-poisoning for the years #aijb to #aijd1 as given herewith3 ,,lead-,,poisoning ,,cases ,,contracted ,,no4 ,,of ,,cases ,,days ,,of ,,sickness,,at ,,rever4 ,,at ,,and ,h4 ,h4 ,,sickness ,,method ,,of ,,year ,,no4 ,,of,,total,,per #ajj ,,total ,,per #ajj ,,sint4 ,,fur4 ,,working ,,men ,,persons ,,persons ,,fur4 ,old #aijb #ic #ae #af4a #bdf #bfd4e #aa #d #aijc #hf #ab #ac4i #bbb #beh4a #g #e ,h4-,h4 #aijd #hg #h #i4b #bdb #bgh4b #f #b ,this shows a gratifying decrease in the number of cases1 namely1 from #af4a to #i4b per cent42 this decrease would have been still greater if ,huntington-,heberlein furnaces had been in use exclusively4 ,however1 most of the time two or three sintering furnaces were fired for working up by-products1 #af to #ah men being engaged on that work4 ,the ,huntington-,heberlein furnaces alone 7at which1 in the year #aijd1 #fi men in all were occupied7 show only #b4i per cent4 of cases4 ,that the number of days of illness was not reduced is due to the fact that the cases among the gang of men working at the sintering furnaces were mostly of long standing and took some time to cure4 ,the noxious effects upon the health of the workmen in running the shaft furnaces are due to the fumes from the products made in this operation1 such as work-lead1 matte and slag1 which flow out of the furnace at a temperature far above their melting points4 ,even with the old method of running the shaft furnaces the endeavor has always been to provide as efficiently as possible against the danger caused by this volatilization1 and1 wherever feasible1 to install safety appliances to prevent the escape of lead vapors into the work-rooms2 but these measures could not be made as thorough as in the case of the ,huntington-,heberlein process4 ,the principal work in running the shaft furnaces1 aside from the charging1 consists in tapping the slag and pouring out the work-lead4 ,other unpleasant jobs are the barring down 7which in the old process had to be done frequently7 and the cleaning out of the furnace after blowing out4 ,in the old process the slag formed in the furnace flows out continuously through the tap-hole into iron pots placed in front of the spout4 ,a number of such pots are so arranged on a revolving table that as soon as one is filled the next empty can be brought up to the duct2 thus the slag first poured in has time to cease fuming and to solidify before it is removed4 ,the vapors arising from the slag as it flows out are conveyed away through hoods4 ,at the same time with the slag1 lead matte also issues from the furnace4 ,now the greater the quantity of lead matte1 the more smoke is also produced2 and1 with the comparatively high proportion of lead matte resulting from the old process1 the quantity of smoke was so great that the ventilation appliances were no longer sufficient to cope with it1 thus allowing vapors to escape into the work-room4 ,the work-lead collects at the back of the furnace in a well1 from which it is from time to time ladled into molds placed near by4 ,if the lead is allowed to cool sufficiently in the well1 it does not fume much in the ladling out4 ,but when the furnace runs very hot 7which sometimes happens71 the lead also is hotter and is more inclined to volatilize4 ,in this event the danger of lead-poisoning is very great1 for the workman has to stand near the lead sump4 ,a still greater danger attends the work of barring down and cleaning out the furnace4 ,the barring down serves the purpose of loosening the charge in the zone of fusion2 at the same time it removes any crusts formed on the sides of the furnace1 or obstructions stopping up the tuyeres4 ,with the old furnaces1 and their strong tendency to crust1 this work had to be undertaken almost every day1 the men being compelled to work for rather a long time and often very laboriously with the heavy iron tools in the immediate neighborhood of the glowing charge1 the front of the furnace being torn open for this purpose4 ,in this operation they were exposed without protection to the metallic vapors issuing from the furnace1 inasmuch as the ventilating appliances had to be partially removed during this time1 in order to render it at all possible to do the work4 ,in a similar manner1 but only at the time of shutting down a shaft furnace1 the cleaning out 7that is to say1 the withdrawing of no longer fused but still red-hot portions of the charge left in the furnace7 is carried out4 ,in this process1 however1 the glowing material brought out could be quenched with cold water to such a point that the evolution of metallic vapors could be largely avoided4 ,lastly1 the mode of charging of the shaft furnace is also to be regarded as a cause of poisoning1 inasmuch as it is impossible to avoid entirely the raising of dust in the repeated act of dumping and turning over the materials for smelting1 in preparing the mix1 and in subsequently charging the furnace4 ,by the introduction of the ,huntington-,heberlein process1 all these disadvantages1 both in the roasting operation and in running the shaft furnaces1 are in part removed altogether1 in part reduced to such a degree that the danger of injury is brought to a minimum4 ,in furnaces in which the product of the ,huntington-,heberlein roast is smelted1 the slag is tapped only periodically at considerable intervals2 and1 as there is less lead matte produced than formerly1 the quantity of smoke is never so great that the ventilating fan cannot easily take care of it4 ,there is therefore little chance of any smoke escaping into the working-room4 ,as the production of work-lead1 especially in the case of the large shaft furnace1 is very considerable1 so that the lead continually flows out in a big stream into the well1 the hand ladling has to be abandoned4 ,therefore the lead is conducted to a large reservoir standing near the sump1 and is there allowed to cool below its volatilizing temperature4 ,as soon as this tank is full1 the lead is tapped off and 7by the aid of a swinging gutter7 is cast into molds ready for this purpose4 ,both the sump and the reservoir-tank are placed under a fume-hood4 ,the swinging gutter is covered with sheet-iron lids while tapping1 so that any lead volatilized is conveyed by the gutter itself to a hood attached to the reservoir2 thus the escape of metallic vapors into the working space is avoided1 as far as possible4 ,this method of pouring does not entail the same bodily exertion as the ladling of the lead2 moreover1 as it requires but little time1 it gives the workmen frequent opportunity to rest4 ,but one of the chief advantages of the ,huntington-,heberlein process lies in the entire omission of the barring down4 ,if the running of the shaft furnace is conducted with any degree of care1 disorders in the working of the furnace do not occur1 and one can rely on a perfectly regular course of the smelting process day after day4 ,no formation of any crusts interfering with the operation of the furnace has been recorded during any of the campaigns1 which have1 in each case1 lasted nearly a year4 ,as regards the cleaning out of the furnace1 this cannot be avoided on blowing out the ,huntington-,heberlein shaft furnace2 but at most it occurs only once a year1 and can be done with less danger to the workmen1 owing to the better equipment4 ,further1 the charge is thrown straight into the furnace 7in the case of the large shaft furnace72 thus the repeated turning over of the smelting material1 as formerly practised1 becomes unnecessary1 and the deleterious influence of the unavoidable formation of dust is much diminished4 ,the accompanying statistics of sickness due to lead-poisoning in connection with the operation of the shaft furnace 7referring to the same period of time as those given above for the roasting furnaces7 confirm the above statements4 ,,lead-,,poisoning--,,shaft ,,furnaces ,,year,,no4 ,,of ,,men ,,cases ,,days ,,of ,,illness ,,total,,per #ajj ,,persons,,total,,per #ajj ,,persons #aijb #bej #eh #bc4b #ief #chb4d #aijc #bfg #ei #bb4a #ajdd #cia4j #aijd #bcb #bd #aj4c #ecj #bbh4d ,if it were possible to make the necessary distinctions in the case of the large shaft furnace1 the diminution in sickness from lead-poisoning would be still more apparent2 for1 among the furnace attendants proper1 there has been no illness2 all cases of poisoning have occurred among the men who prepare the charge1 who break up the roasted material1 and others who are occupied with subsidiary work4 ,some of these are exposed to illness through their own fault1 owing to want of cleanliness1 or to neglect of every precautionary measure against lead-poisoning4 ,thus far we have dealt only with the advantages and improvements of the ,huntington-,heberlein process2 we will now1 in conclusion1 consider also its disadvantages4 ,the chief drawback of the new process lies in the difficulty of breaking up the blocks of the roasted product from the converters1 a labor which1 apart from the great expense involved1 is also unhealthy for the workmen engaged thereon4 ,seemingly this evil is still further increased by working with larger charges in the #aj ton converters1 as projected2 but in this case it is proposed to place the converters in an elevated position1 and to cause the blocks to be shattered by their fall from a certain hight1 so that further breaking up will require but little work4 ,trials made in this direction have already yielded satisfactory results1 and seem to promise that the disadvantage will in time become less important4 ,another unpleasant feature is the presence 7in the waste gases from the converters7 of a higher percentage of sulphur dioxide1 the suppression of which1 if it is feasible at all1 might be fraught with trouble and expense4 ,that the roaster gases from the reverberatory-smelting and sintering furnaces did not show such a high percentage of sulphur dioxide must be ascribed chiefly to the circumstance that the roasting was much slower1 and that the gases were largely diluted with air already at the point where they are formed1 as the work must always be done with the working-doors open4 ,in the ,huntington-,heberlein process1 on the other hand1 the aim is to prevent1 as far as possible1 the access of air from outside while blowing the charge4 ,the more perfectly this is effected1 and the greater the quantity of ore to be blown in the converters1 the higher will also be the percentage of sulphur dioxide in the waste gases4 ,this circumstance has not only furnished the inducement1 but it has rendered it possible to approach the plan of utilizing the sulphur dioxide for the manufacture of sulphuric acid4 ,if this should be done successfully 7which1 according to the experiments carried out1 there is reasonable ground to expect71 the present disadvantage might be turned into an advantage4 ,this has the more significance because an essential constituent of the lead ore--the sulphur--will then no longer1 as hitherto1 have to be regarded as wholly lost4#ca ,,the ,,huntington-,,heberlein ,,process ,,by ,,thomas ,,huntington ,,and ,,ferdinand ,,heberlein 7,may #bf1 #aijf7 ,this process for roasting lead sulphide ores has now fairly established itself in all parts of the world1 and is recognized by metallurgical engineers as a successful new departure in the method of desulphurization4 ,it offers the great advantage over previous methods of being a more scientific application of the roasting reactions 7of the old well-used formul ,pb,s #c,o ,pb,o ,,so and ,pb,s ,pb,s,o #b,o #b,pb,o #b,,so7 and admits of larger quantities being handled at a time1 so that the use of fuel and labor are in proportion to the results achieved1 and also there is less waste all around in so far as the factors necessary for the operation--fuel1 labor and air--can be more economically used4 ,the workman's time and strength are not employed in laboriously shifting the ore from one part of the furnace to another with a maximum amount of exertion and a minimum amount of oxidation4 ,the fuel consumed acts more directly upon the ore during the first part of the process in the furnace and its place is taken by the sulphur itself during the final and blowing stage1 so that during the whole series of operations more concentrated gases are produced and consequently the large excess of heated air of the old processes is avoided to such an extent that the gases can be used for the production of sulphuric acid4 ,with a modern well-constructed plant practically all the evils of the old hand-roasting furnaces are avoided1 and besides the notable economy achieved by the ,h4-,h4 process itself1 the health and well-being of the workmen employed are greatly advanced1 so that where hygienic statistics are kept it is proved that lead-poisoning has greatly diminished4 ,it is only natural1 therefore1 that the ,h4-,h4 process should have been a success from the start1 popular alike with managers and workmen once the difficulties inseparable from the introduction of any new process were overcome4 ,simple as the process now appears1 however1 it is the result of many years of study and experiment1 not devoid of disappointments and at times appearing to present a problem incapable of solution4 ,the first trials were made in the smelting works at ,pertusola1 ,italy1 as far back as #ahhi1 where considerable sums were devoted every year to this experimental work and lead ore roasting was almost continuously on the list of new work from #ahge on4 ,it may be interesting to mention that at this time the ,montevecchio ores 7containing about #gj per cent4 lead and about #ae per cent4 sulphur1 together with a certain amount of zinc and iron7 were considered highly refractory to roast1 and the only ores approved of by the management of the works at this date were the ,monteponi and ,san ,giovanni first-class ores 7containing about #hj per cent4 lead71 and the second-class carbonates 7with at least #fj per cent4 lead and #e per cent4 sulphur74 ,it must be noted that a modified ,flintshire reverberatory process was in use in the works1 which could deal satisfactorily only with this class of ore1 so that1 as these easy ores diminished in quantity every year and their place was taken by the 8refractory0 ,montevecchio type1 the roasting problem was always well to the front at the ,pertusola works4 ,it may be asserted that almost every known method of desulphurization was examined and experimented upon on a large scale4 ,gas firing was exclusively used on certain classes of ores for several years with considerable success1 and revolving furnaces of the ,brckner type--gas fired--were also tried4 ,although varying degrees of success were obtained1 no really great progress was made in actual desulphurization2 methods were cheapened and larger quantities handled at a time1 but the final product--whether sintered or in a pulverulent state--seldom averaged much under #e per cent4 sulphur1 while the days of the old 8gray slags0 7#a per cent4 to #b per cent4 sulphur7 from the reverberatories totally disappeared1 together with the class of ores which produced them4 ,during the long period of these experiments in desulphurization various facts were established3 7#a7 ,that sulphide of lead--especially in a pulverulent state--could not be desulphurized in the same way as other sulphides1 such as sulphides of iron1 copper1 zinc1 etc41 because if roasted in a mechanical furnace the temperature had to be kept low enough to avoid premature sintering1 which would choke the stirrers and cause trouble by the ore clogging on the sides and bottom of the furnace4 ,if1 however1 the ore was roasted in a 8dry state0 at low temperature1 a great deal of sulphur remained in the product as sulphate of lead1 which was as bad for the subsequent blast-furnace work as the sulphide of lead itself4 ,when air was pressed through molten galena--in the same way as through molten copper matte--a very heavy volatilization of lead took place1 while portions of it were reduced to metal or were contained as sulphide in the molten matte1 so that a good product was not obtained4 7#b7 ,that no complete dead roast of lead ores could be obtained unless the final product was thoroughly smelted and agglomerated4 7#c7 ,that a well roasted lead ore could be obtained by oxidizing the ,pb,s with compressed air1 after the ore had been suitably prepared4 7#d7 ,that metal losses were mainly due to the excessive heat produced in the oxidation of ,pb,s to ,pb,o1 and other sulphides present in the ore4 ,it was by making use of these facts that the ,h4-,h4 roasting process was finally evolved1 and by carefully applying its principles it is possible to desulphurize completely the ore to a practically dead roast of under #a per cent4 sulphur2 in practice1 however1 such perfection is unnecessary and a well agglomerated product with from #b to #b4e per cent4 sulphur is all that is required4 ,during some trials in ,australia1 where a great degree of perfection was aimed at1 a block of over #bjjj tons of agglomerated1 roasted ore was produced containing #a per cent4 sulphur 7as sulphide72 as the ores contained an average of about #aj per cent4 ,zn1 this was a very fine result from a desulphurization point of view1 but it was not found that this #a per cent4 product gave any better results in the subsequent smelting in the blast furnace than later on a less carefully prepared material containing #b4e per cent4 sulphur4 ,in the early stages of experiment the great difficulty was to obtain agglomeration without first fusing the sulphides in the ore1 and turning out a half-roasted product full of leady matte4 ,simple as the thing now is1 it seemed at times impossible to avoid this defect1 and it was only by a careful study of the effects of an addition of lime1 ,fe,o or ,mn,o1 and their properties that the right path was struck4 ,before the introduction of the ,h4-,h4 process lime was only used in the reverberatory process 7,flintshire and ,tarnowitz7 to stiffen the charge1 but as ,percy tells us that after its addition the charge was glowing1 it must have had a chemical as well as a mechanical effect4 ,in recognition of this fact fine caustic lime or crushed limestone was mixed with the ore before charging it into the furnace and exposing it to an oxidizing heat4 ,it was thought probable that a dioxide of lime might be temporarily formed1 which in contact with ,pb,s would be decomposed immediately after its formation1 or that the ,ca,o served as ,contactsubstanz in the same way as spongy platinum1 metallic silver1 or oxide of iron4 ,as ,ca,s,o and not ,ca,s,o is always found in the roasted ore1 this may prove that ,ca,o is really a contact substance for oxygen 7see ,w4 ,m4 ,hutchings1 ,engineering and ,mining ,journal1 ,oct4 #ba1 #aije1 ,vol4 ,,lxxx1 p4 #gbf74 ,the fact that the process works equally well with ,fe,o instead of ,ca,o speaks against the theory of plumbate of lime4 ,whatever theory may be correct1 the fact remains that ,ca,o assists the roasting process and that by its use the premature agglomeration of the sulphide ore is avoided4 ,a further advantage of lime is that it keeps the charge more porous and thus facilitates the passage of the air4 ,the shape and size of the blowing apparatus best adapted for the purpose in view occupied many months2 starting from very shallow pans or rectangular boxes several feet square with a few inches of material over a perforated plate1 it gradually resolved itself into the cone-shaped receptacle--holding about a ton of ore--as first introduced together with the process4 ,in later years and in treating larger quantities a more hemispherical form has been adopted1 containing up to #ae tons of ore4 ,it is probable about eight years were employed in actually working out the process before it was introduced on any large scale at ,pertusola1 but by the end of #ahih the greater part of the ,pertusola ores were treated by the process4 ,its first introduction to any other works was in #aijj1 when it was started outside its home for the first time at ,braubach 7,germany74 ,since then its application has gradually extended1 proceeding from ,europe to ,australia and ,mexico and finally to ,america and ,canada1 where recognition of its merits was more tardy than elsewhere4 ,it is now practically in general use all over the world and is recognized as a sound addition to metallurgical progress4 ,it is doubtless only a step in the right direction and with its general use a better knowledge of its principles will prevail1 so that its future development in one direction or another1 as compared with present results1 may show some further progress4 ,the present working of the ,h4-,h4 process still follows practically the original lines laid down1 and by preliminary roasting in a furnace with lime1 oxide of iron1 or manganese 7if not already contained in the ore71 prepares the ore for blowing in the converter4 ,mechanical furnaces have been introduced to the entire exclusion of the old hand-roasters1 and the size of the converters has been gradually increased from the original one-ton apparatus successively to #e1 #g and #aj ton converters2 at present some for #ae tons are being built in ,germany and will doubtless lead to a further economy4 ,the mechanical furnace at present most in use is a single-hearth revolving furnace with fixed rabbles1 the latest being built with a diameter of #bf ft4 and a relatively high arch to ensure a clear flame and rapid oxidation of the ore4 ,the capacity of these furnaces varies1 of course1 with the nature of the ores to be treated1 but with ordinary lead ores 7,european and ,australian practice7 of from #ej per cent4 to #fj per cent4 lead and #ad per cent1 to #ah per cent4 sulphur1 the average capacity may be taken at about #ej to #fj tons of crude ore per day of #bd hours4 ,the consumption of coal with a well-constructed furnace is very low and is always under #h per cent4--#f per cent4 being perhaps the average4 ,these furnaces require very little attention1 being automatic in their charging and discharging arrangements4 ,the ore on leaving the furnace is charged into the converters by various mechanical means 7,jacob's ladders1 conveyors1 etc474 ,the converter charge usually consists of some hot ore direct from the furnace1 on top of which ore is placed which has been cooled down by storage in bins or by the addition of water4 ,the converter is generally filled in two charges of five tons each1 and the blowing time should not be more than #d to #f hours4 ,the product obtained should be porous and well agglomerated1 but easily broken up1 tough melted material being due to an excess of silica and too much lead sulphide4 ,attention1 therefore1 to these two points 7good preliminary roasting and correction of the charge by lime7 obviates this trouble4 ,this roasted ore should not contain more than about #a4e to #b per cent4 sulphur1 and in a modern blast furnace gives surprisingly good results1 the matte-fall being in most cases reduced to nothing1 and the capacity of the furnace is largely increased1 while the slags are poorer4 ,if the converter charge has been properly prepared1 the blowing operation proceeds with the greatest smoothness and requires very little attention on the part of the workmen1 the heat and oxidation rise gradually from the bottom and volatilization losses remain low1 so that it is possible1 if desired1 to produce hot concentrated sulphurous gases suitable for the manufacture of sulphuric acid4 ,besides the actual economy obtained in roasting ores by the process1 a great feature of its success has been the remarkable improvement in smelting and reducing the roasted ore as compared with previous experience4 ,this is due to the nature of the roasted material1 which1 besides being much poorer in sulphur than was formerly the case1 is thoroughly porous and well agglomerated and contains--if the original mixture is properly made--all the necessary slagging materials itself1 so that it practically becomes a case of smelting slags instead of ore1 and to an expert the difference is evident4 ,experience has shown that on an average the improvement in the capacity of the blast furnace may be taken at about #ej to #ajj per cent41 so that in works using the ,h4-,h4 process--after its complete introduction--about half the blast furnaces formerly necessary for the same tonnage were blown out4 ,the matte-fall has become a thing of the past1 so that1 except in those cases where some matte is required to collect the copper contained in the ores1 lead matte has disappeared and the quantity of flue dust as well as the lead and silver losses have been greatly reduced4 ,referring to the latest history of the ,h4-,h4 process1 and the theory of direct blowing1 it may be remarked--putting aside all legal questions--that the idea1 metallurgically speaking1 is attractive1 as it would seem that by eliminating one-half of the process and blowing the ores direct without the expense of a preliminary roast a considerable economy should be effected4 ,upon examination1 however1 this supposed economy and simplicity is not at all of such great importance1 and in many cases1 without doubt1 would be retrogressive in lead ore smelting rather than progressive4 ,when costs of roasting in a furnace are reduced to such a low figure as can be obtained by using #ej ton furnaces and #aj to #ae ton converters1 there is very little margin for improvement in this direction4 ,from the published accounts of the ,tarnowitz smelting works 7the ,engineering and ,mining ,journal1 ,sept4 #bc1 #aije1 ,vol4 ,,lxxx1 p4 #ece7 the cost of mechanical preliminary roasting cannot exceed #be;c4 per ton1 so that even assuming direct blowing were as cheap as blowing a properly prepared material1 the total economy would only be the above figure1 viz41 #be;c42 but this is far from being the case4 ,direct blowing of a crude ore is considerably more expensive than dealing with the ,h4-,h4 product1 because of necessity the blowing operation must be carried out slowly and with great care so as to avoid heavy metal losses1 and whereas a pre-roasted ore can be easily blown in four hours and one man can attend to two or three #aj ton converters1 the direct blowing operation takes from #ab to #ah hours and requires the continual attention of one man4 ,in the first case the cost of labor would be3 ,one man at say #c for #ej tons 7at least71 i4e41 #f;c4 per ton1 and in the second case one man at #c for #aj tons 7at the best71 i4e41 #cj;c41 a difference in favor of pre-roasting of #bd;c41 so that any possible economy would disappear4 ,furthermore1 as the danger of blowing upon crude sulphides for #ab or #ah hours is greater as regards metal losses than a quick operation of four hours1 it is very likely that instead of an economy there would be an increase in cost1 owing to a greater volatilization of metals4 ,these remarks refer to ordinary lead ores with say #ej per cent4 lead and about #ad per cent4 sulphur4 ,with ores1 however1 such as are generally treated in the ,united ,states the advantages of pre-roasting are still more evident4 ,these ores contain about #aj to #ae per cent4 lead1 #cj to #dj per cent4 sulphur1 #bj to #cj per cent4 iron1 #aj per cent4 zinc1 #e per cent4 silica1 and lose the greater part of the pyritic sulphur in the preliminary roasting1 leaving the iron in the form of oxide1 which in the subsequent blowing operation acts in the same way as lime4 ,for this reason the addition of extra fluxes1 such as limestone1 gypsum1 etc41 to the original ore is not necessary and only a useless expense4 ,in certain exceptional cases and with ores poor in sulphur1 direct blowing might be applicable1 but for the general run of lead ores no economy can be expected by doing away with the preliminary roast4 ,,making ,,sulphuric ,,acid ,,at ,,broken ,,hill 7,august #aa1 #aijd7 ,the ,broken ,hill ,proprietary ,company has entered upon the manufacture of sulphuric acid on a commercial scale4 ,the acid is practically a by-product1 being made from the gases emanating from the desulphurization of the ores1 concentrates1 etc41 by the ,carmichael-,bradford process4 ,the acid can be made at a minimum of cost1 and thus materially enhances the value of the process recently introduced for the separation of zinc blende from the tailings by flotation4 ,the following particulars are taken from a recently published description of the process3 ,the ores1 concentrates1 slimes1 etc41 as the case may be1 are mixed with gypsum1 the quantity of the latter varying from #ae to #be per cent4 ,the mixture is then granulated to the size of marbles and dumped into a converter4 ,the bottom of the charge is heated from #djj to #ejj deg4 ,c4 ,it is then subjected to an induced current of air1 and the auxiliary heat is turned off4 ,the desulphurization proceeds very rapidly with the evolution of heat and the gases containing sulphurous anhydride4 ,the desulphurization is very thorough1 and no losses occur through volatilization4 ,the sulphur thus rendered available for acid making is rather more than is contained in the ore1 the sulphur in the agglomerated product being somewhat less than that accounted for by the sulphur contained in the added gypsum4 ,thus from one ton of #ad per cent4 sulphide ore it is possible to make about #ab cwt4 of chamber acid1 fully equaling #g cwt4 of strong acid4 ,the plant at present in use1 which comprises a lead chamber of #dj1jjj cu4 ft41 can turn out #ce tons of chamber acid per week4 ,this plant is being duplicated1 and it has also been decided to erect a large plant at ,port ,pirie for use in the manufacture of superphosphates4 ,it is claimed that the production of sulphuric acid from ores containing only #ad per cent4 of sulphur establishes a new record4 ,,the ,,carmichael-,,bradford ,,process ,,by ,,donald ,,clark 7,november #c1 #aijd7 ,subsequent to the introduction of the ,huntington-,heberlein process in ,australia1 ,messrs4 ,carmichael and ,bradford1 two employees of the ,broken ,hill ,proprietary ,company1 patented a process which bears their name4 ,instead of starting with lime1 or limestone and galena1 as in the ,huntington-,heberlein process1 they discovered that if sulphate of lime is mixed with galena and the temperature raised1 on blowing a current of air through the mixture the temperature rises and the mass is desulphurized4 ,the process would thus appear to be a corollary of the original one1 and the reactions in the converter are identical4 ,owing to the success of the acid processes in separating zinc sulphide from the tailing at ,broken ,hill1 it became necessary to manufacture sulphuric acid locally in large quantity4 ,the ,carmichael-,bradford process has been started for the purpose of generating the sulphur dioxide necessary1 and is of much interest as showing how gases rich enough in ,,so may be produced from a mixture containing only from #ac to #af per cent4 sulphur4 ,gypsum is obtained in a friable state within about five miles from ,broken ,hill4 ,this is dehydrated1 the ,ca,s,o1 #b;,h,o being converted into ,ca,s,o on heating to about #bjj deg4 ,c4 ,the powdered residue is mixed with slime produced in the milling operations and concentrate in the proportion of slime #c parts1 concentrate #a part1 and lime sulphate #a part4 ,the proportions may vary to some extent1 but the sulphur contents run from #ac to #af or #ag per cent4 ,the average composition of the ingredients is as given in the table on the next page4 ,these materials are moistened with water and well mixed by passing them through a pug-mill4 ,the small amount of water used serves to set the product1 the lime sulphate partly becoming plaster of paris1 #b;,ca,s,o1 ,h,o4 ,while still moist the mixture is broken into pieces not exceeding two inches in diameter and spread out on a drying floor1 where excess of moisture is evaporated by the conjoint action of sun and wind4 ,,slime,,concentrate,,calcium ,,average ,,sulphate ,galena #bd #gj #bi ,blende #cj #ae #ba ,pyrite #c #b ,ferric oxide #d #b4e ,ferrous oxide #a #a ,manganous oxide #f4e #e ,alumina #e4e #c ,lime #c4e #da #aj ,silica #bc #ad ,sulphur trioxide #ei #ab ,the pots used are small conical cast-iron ones1 hung on trunnions1 and of the same pattern as used in the ,huntington-,heberlein process4 ,three of these are set in line1 and two are at work while the third is being filled4 ,these pots have the same form of conical cover leading to a telescopic tube1 and all are connected to the same horizontal pipe leading to the niter pots4 ,dampers are provided in each case4 ,a small amount of coal or fuel is fed into the pots and ignited by a gentle blast2 as soon as a temperature of about #djj to #ejj deg4 ,c4 is attained the dried mixture is fed in1 until the pot is full2 the cover is closed down and the mass warms up4 ,water is first driven off1 but after a short time concentrated fumes of sulphur dioxide are evolved4 ,the amount of this gas may be as much as #ad per cent41 but it is usually kept at about #aj per cent41 so as to have enough oxygen for the conversion of the dioxide to the trioxide4 ,the gases are led over a couple of niter pots and thence to the usual type of lead chamber having a capacity of #dj1jjj cu4 ft4 ,chamber acid alone is made1 since this requires to be diluted for what is known as the saltcake process4 ,the plant has now been in operation for some time and1 it is claimed1 with highly successful results4 ,the product tipped out of4 the converter is similar to that obtained in the ,huntington-,heberlein process1 and is at once fit for the smelters1 the amount of sulphur left in it being always less than that originally introduced with the gypsum2 analysis of the desulphurized material shows usually from #c to #d per cent4 sulphur4 ,,the ,,carmichael-,,bradford ,,process ,,by ,,walter ,,renton ,,ingalls 7,october #bh1 #aije7 ,as described in ,united ,states patent ,no4 #gje1ijd1 issued ,july #bi1 #aijb1 lead sulphide ore is mixed with #aj to #ce per cent4 of calcium sulphate1 the percentage varying according to the grade of the ore4 ,the mixture is charged into a converter and gradually heated externally until the lower portion of the charge1 say one-third to one-fourth1 is raised to a dull-red heat2 or the reactions may be started by throwing into the empty converter a shovelful of glowing coal and turning on a blast of air sufficient to keep the coal burning and then feeding the charge on top of the coal4 ,this heating effects a reaction whereby the lead sulphide of the ore is oxidized to sulphate and the calcium sulphate is reduced to sulphide4 ,the heated mixture being continuously subjected to the blast of air1 the calcium sulphide is re-oxidized to sulphate and is thus regenerated for further use4 ,this reaction is exothermic1 and sufficient heat is developed to complete the desulphurization of the charge of ore by the concurrent reactions between the lead sulphate 7produced by the calcium sulphate7 and portions of undecomposed ore1 sulphurous anhydride being thus evolved4 ,the various reactions1 which are complicated in their nature1 continue until the temperature of the charge reaches a maximum1 by which time the charge has shrunk considerably in volume and has a tendency to become pasty4 ,this becomes more marked as the production of lead oxide increases1 and as the desired point of desulphurization is attained the mixture fuses2 at this stage the calcium sulphide which is produced from the sulphate cannot readily oxidize1 owing to the difficulty of coming into actual contact with the air in the pasty mass1 but1 being subjected to the strong oxidizing effect of the metallic oxide1 it is converted into calcium plumbate1 while sulphurous anhydride is set free4 ,the mass then cools1 as the exothermic reactions cease1 and can be readily removed to a blast furnace for smelting4 ,the reactions above described are as outlined in the original ,american patent specification4 ,irrespective of their accuracy1 the ,carmichael-,bradford process is obviously quite similar to the ,huntington-,heberlein1 and doubtless owes its origin to the latter4 ,the difference between them is that in the ,huntington-,heberlein process the ore is first partially roasted with addition of lime1 and is then converted in a special vessel4 ,in the ,carmichael-,bradford process the ore is mixed with gypsum and is then converted directly4 ,the greatest claim for originality in the ,carmichael-,bradford process may be considered to lie in it as a method of desulphurizing gypsum1 inasmuch as not only is the sulphur of the ore expelled1 but also a part of the sulphur of the gypsum2 and the sulphur is driven off as a gas of sufficiently high tenor of sulphur dioxide to enable sulphuric acid to be made from it economically4 ,up to the present time the ,carmichael-,bradford process has been put into practical use only at ,broken ,hill1 ,n4 ,s4 ,w4 ,the ,broken ,hill ,proprietary ,company first conducted a series of tests in a converter capable of treating a charge of #bj cwt4 ,these tests were made at the smelting works at ,port ,pirie4 ,exhaustive experiments made on various classes of ores satisfactorily proved the general efficacy of the process4 ,the following ores were tried in these preliminary experiments1 viz43 ,first-grade concentrate containing3 ,pb1 #fj per cent42 ,zn1 #aj per cent42 ,s1 #af per cent42 ,ag1 #cj oz4 ,second-grade concentrate containing3 ,pb1 #de per cent42 ,zn1 #ab4e per cent42 ,s1 #ad4e per cent42 ,ag1 #bb oz4 ,slime containing3 ,pb1 #ba per cent42 ,zn1 #ag per cent42 ,s1 #ac per cent42 ,ag1 #ah oz4 ,lead-copper matte containing3 ,fe1 #db per cent42 ,pb1 #ag per cent42 ,zn1 #ac4c per cent42 ,cu1 #b4d per cent42 ,s1 #bc per cent42 ,ag1 #be oz4 ,other mattes1 of varying composition up to #de per cent4 ,pb and #ajj oz4 ,ag1 were also tried4 ,the results from these preliminary tests were so gratifying that a further set of tests was made on lead-zinc slime1 with a view of ascertaining whether any volatilization losses occurred during the desulphurization4 ,this particular material was chosen because of its accumulation in large proportions at the mine1 and the unsatisfactory result of the heap roasting which has recently been practised4 ,the heap roasting1 although affording a product containing only #g per cent4 ,s1 which is delivered in lump form and therefore quite suitable for smelting1 resulted in a high loss of metal by volatilization 7#ag per cent4 ,pb1 #e per cent4 ,ag74 ,the result of nine charges of the slime treated by the ,carmichael-,bradford process was as follows3 ,,assays ,,contents ,cwt4 ,pb ,ag oz4,zn ,s ,pb ,ag4 ,zn ,s cwt4 oz4 cwt4cwt4 ,raw slime #abh4a #ba4c #ah4j #af4hac4abg4bhaae4cbf4baf4gh ,raw gypsum #ed4i #i4hh ,total #ahc4j #bg4bhaae4cbe4bbf4ff ,sintered material#aji4hhbj4g #ag4b #d4hjbb4gd #id4e #e4bg ,middling #ad4dgag4g #ae4g #f4bj #b4ef #aa4c #j4hi ,fines #aa4abai4j #ad4h #g4ej #b4aa #h4b #j4hc ,total #ace4dg #e4agbg4daaac4j #f4ii ,these results indicated practically no volatilization of lead and silver during the treatment1 the lead showing a slight increase1 viz41 #j4dg per cent41 and the silver #a4ac per cent4 loss4 ,a desulphurization of #gj4d per cent4 was effected4 ,a higher desulphurization could have been effected had this been desired4 ,in the above tabulated results1 the term 8middling0 is applied to the loose fritted lumps lying on the top of the charge3 these are suitable for smelting1 the fines being the only portion which has to be returned4 ,in order to test the practicability of making sulphuric acid1 a plant consisting of three large converters of capacity of five tons each1 together with a lead chamber #ajj ft4 by #bj ft4 by #bj ft41 was then erected at ,broken ,hill1 together with a dehydrating furnace1 pug-mill1 and granulator4 ,these converters are shown in the accompanying engravings4 ,a trial run was made with #ajh tons of concentrate of the following composition3 #ed per cent4 lead2 #a4i per cent4 iron2 #j4i per cent4 manganese2 #i4d per cent4 zinc2 #ad4f per cent4 sulphur2 #ai4b per cent4 insoluble residue1 and #bd oz4 silver per ton4 ,the converter charge consisted of #ajj parts of the concentrate and #be parts of raw gypsum1 crushed to pass a #a in4 hole and retained by a #j4be in4 hole1 the material finer than #j4be in4 7which amounted to #e per cent4 of the total7 being returned to the pug-mill4 ,after desulphurization in the converter1 the product assayed as follows3 #dh4i per cent4 lead2 #a4hj per cent4 iron2 #j4hj per cent4 manganese2 #g4hg per cent4 zinc2 #c4ij per cent4 sulphur2 #a4jb per cent4 alumina2 #e4hj per cent4 lime2 #ba4ge per cent4 insoluble residue2 #h4af per cent4 undetermined 7oxygen as oxides1 sulphates1 etc472 total1 #ajj per cent4 ,its silver content was #bb oz4 per ton4 ,the desulphurized ore weighed #aj per cent4 more than the raw concentrate4 ,during this run #cd tons of acid were made4 ,a trial was then made on #ge tons of slime of the following composition3 #ah4j per cent4 lead2 #af4f per cent4 zinc2 #f4j per cent4 iron2 #b4e per cent4 manganese2 #c4b per cent4 alumina2 #b4a per cent4 lime2 #ch4e per cent4 insoluble residue2 total1 #ajj per cent4 ,its silver content was #ai4b oz4 per ton4 ,the converter charge in this case consisted of #ajj parts of raw slime and #cj parts of gypsum4 ,the converted material assayed as follows3 #af4a per cent4 lead2 #ad4j per cent4 zinc2 #c4f per cent4 sulphur2 #e4db per cent4 iron2 #b4be per cent4 manganese2 #d4aj per cent4 alumina2 #h4fj per cent4 lime2 #ci4hj per cent4 insoluble residue2 #f4ac per cent4 undetermined 7oxygen1 etc472 total1 #ajj per cent42 and silver1 #ag4e oz4 per ton4 ,the increase in weight of desulphurized ore over that of the raw ore was #aa per cent4 ,during this run #bb tons of acid were manufactured4 ,the analysis of the gypsum used in each of the above tests 7at ,broken ,hill7 was as follows3 #gf4a per cent4 ,ca,s,o1 #b;,h,o2 #j4e per cent4 ,fe,o2 #d4e per cent4 ,al,o2 #ah4i per cent4 insoluble residue4 ,the plant was then put into continuous operation on a mixture of three parts slime and one of concentrate1 desulphurizing down to #d per cent4 ,s1 and supplying #bj tons of acid per week1 and additions were made to the plant as soon as possible4 ,the acid made at ,broken ,hill has been used in connection with the ,delprat process for the concentration of the zinc tailing4 ,at ,port ,pirie1 works are being erected with capacity for desulphurization of about #ce1jjj tons per annum1 with an acid output of #aj1jjj tons4 ,this acid is to be utilized for the acidulation of phosphate rock4 ,illustration3 ,,fig4 #ae4--;,details of ,converters4 ,the cost of desulphurization of a ton of galena concentrate by the ,carmichael-,bradford process1 based on labor at #a4hj per #h hours1 gypsum at #b4dj per #bbdj lb41 and coal at #h4dj per #bbdj lb41 is estimated as follows3 #j4be ton of gypsum #j4fj ,dehydrating and granulating gypsum 4#dh ,drying mixture of ore and gypsum 4#ab ,converting 4#bd ,spalling sintered material 4#ab #j4ja ton coal 4#jh ---------- ,total #a4fd ,the lime in the sintered product is credited at #ab;c41 making the net cost #a4eb per ton 7#bbdj lb47 of ore4 ,the plant required for the ,carmichael-,bradford process can be described with sufficient clearness without drawings1 except the converters4 ,the ore 7concentrate1 slime1 etc47 to be desulphurized is delivered at the top of the mill by cars1 conveyors1 or other convenient means1 and dumped into a bin4 ,two screw feeders placed inside the bin supply the mill with ore1 uniformly and as fast as it is required4 ,these feeders deliver the ore into a chute1 which directs it into a vertical dry mixer4 ,a small bin1 on the same level as the ore-bin1 receives the crude gypsum from cars4 ,thence it is fed automatically to a disintegrator1 which pulverizes it finely and delivers it into a storage bin underneath4 ,this disintegrator revolves at about #agjj r4p4m4 and requires #aj h4p4 ,the body of the machine is cast iron1 fitted with renewable wearing plates 7made of hard iron7 in the grinding chamber4 ,the revolving parts consist of a malleable iron disc in which are fixed steel beaters1 faced on the grinding surface with highly tempered steel4 ,the bin that receives the floured gypsum contains a screw conveyor similar to those in the ore-bin1 and dumps the material into push conveyors passing into the dehydrating furnace4 ,they carry the crushed gypsum along at a speed of about #a ft4 per minute1 and allow about #bj ft4 to dehydrate the gypsum4 ,this speed can1 of course1 be regulated to suit requirements4 ,the dehydrated gypsum runs down a chute into an elevator boot1 and is elevated into a bin which is on the same level as the ore-bin4 ,this bin also contains a screw conveyor1 like that in the ore-bin4 ,the speed of delivery is regulated to deliver the right proportion of dehydrated gypsum to the mixer4 ,the mixer is of the vertical pattern and receives the sulphide ore and dehydrated gypsum from the screw feeders4 ,in it are set two flat revolving cones running at different speeds1 thus ensuring a thorough mixture of the gypsum and ore4 ,the mixed material drops from the cones upon two baffle plates1 and is wetted just before entering the pug-mill4 ,the pug-mill is a wrought-iron cylinder of in4 plate about #b ft4 #f in4 diameter and #f or #h ft4 long1 and has the mixer fitted to the head4 ,it contains a #c ft4 wrought-iron spiral with propelling blades1 which forces the plastic mixture through in4 holes in the cover4 ,the material comes out in long cylindrical pieces1 but is broken up and formed into marble-shaped pieces on dropping into a revolving trommel4 ,the trommel is about #e ft4 long1 #b ft4 in diameter at the small end and about #d ft4 at the large end4 ,it revolves about a wrought-iron spindle 7#b in4 diameter7 carrying two cast-iron hubs to which are fitted arms for carrying the conical plate in4 thick4 ,about #ah in4 of the small end of the cone is fitted with wire gauze1 so as to prevent the material as it comes out of the pug-mill from sticking to it4 ,the trommel is driven by bevel gearing at #bj to #be r4p4m4 ,the granulated material formed in the trommel is delivered upon a drying conveyor4 ,the conveyor consists of hinged wrought-iron plates flanged at the side to keep the material from running off4 ,it is driven from the head by gearing1 at a speed of #a ft4 per minute1 passing through a furnace #aj ft4 long to dry and set the granules of ore and gypsum4 ,this speed can1 of course1 be regulated to suit requirements4 ,the granulated material1 after leaving the furnace1 is delivered to a single-chain elevator1 traveling at a speed of about #aej ft4 per minute4 ,it drops the material into a grasshopper conveyor1 driven by an eccentric1 which distributes the material over the length of a storage bin4 ,from this bin the material is directed into the converters by means of the chutes1 which have their bottom ends hinged so as to allow for the raising of the hood when charging the converters4 ,the converters are shown in the accompanying engravings1 but they may be of slightly different form from what is shown therein1 i4e41 they may be more spherical than conical4 ,they will have a capacity of about four tons1 being #f ft4 in diameter at the top1 #d ft4 in diameter at the false bottom1 and about #e ft4 deep4 ,they are swung on cast-iron trunnions bolted to the body and turned by means of a hand-wheel and worm 7not shown74 ,they are carried on strong cast-iron standards fitted with bearings for trunnions1 and all necessary brackets for tilting gear4 ,the hood has a telescopic funnel which allows it to be raised or lowered1 weights being used to balance it4 ,at the apex of the cone a damper is provided to regulate the draft4 ,a #d in4 hole in the pot allows the air from the blast-pipe1 #ah in4 in diameter1 to enter under the false perforated bottom1 the connection between the two being made by a flexible pipe and coupling4 ,two ,baker blowers supply the blast for the converters4 ,the material1 after being sintered1 is tipped on the floor in front of the converters and is there broken up to any suitable size1 and thence dispatched to the smelters4 ,illustration3 ,,fig4 #af4--;,arrangement of ,converters4 ,the necessary power for a plant with a capacity of #aej tons of ore per day will be supplied by a #ej h4p4 engine4 ,,the ,,savelsberg ,,process ,,by ,,walter ,,renton ,,ingalls 7,december #i1 #aije7 ,there are in use at the present time three processes for the desulphurization of galena by the new method1 which has been referred to as the 8lime-roasting of galena40 ,the ,huntington-,heberlein and the ,carmichael-,bradford processes have been previously described4 ,the third process of this type1 which in some respects is more remarkable than either of the others1 is the invention of ,adolf ,savelsberg1 director of the smeltery at ,ramsbeck1 ,westphalia1 ,germany1 which is owned by the ,akt4 ,gesell4 f4 ,bergbau1 ,blei4 u4 ,zinkhttenbetrieb zu ,stolberg u4 in ,westphalen4 ,the process is in use at the ,ramsbeck and ,stolberg lead smelteries of that company4 ,it is described in ,american patent ,no4 #gee1eih1 issued ,march #bb1 #aijd 7application filed ,dec4 #ah1 #aijc74 ,the process is well outlined in the words of the inventor in the specification of that patent3 8,the desulphurizing of certain ores has been effected by blowing air through the ore in a chamber1 with the object of doing away with the imperfect and costly process of roasting in ordinary furnaces2 but hitherto it has not been possible satisfactorily to desulphurize lead ores in this manner1 as1 if air be blown through raw lead ores in accordance with either of the processes used for treating copper ores1 for example1 the temperature rises so rapidly that the unroasted lead ore melts and the air can no longer act properly upon it1 because by reason of this melting the surface of the ores is considerably decreased1 the greater number of points or extent of surface which the raw ore originally presented to the action of the oxygen of the air blown through being lost1 and1 moreover1 the further blowing of air through the molten mass of ore produces metallic lead and a plumbiferous slag 7in which the lead oxide combines with the gangue7 and also a large amount of light dust1 consisting mainly of sublimated lead sulphide4 ,huntington and ,heberlein have proposed to overcome these objections by adopting a middle course1 consisting in roasting the ores with the addition of limestone for overcoming the ready fusibility of the ores1 and then subjecting them to the action of the current of air in the chamber2 but this process is not satisfactory1 because it still requires the costly previous operation in a roasting furnace4 ,illustration3 ,fig4 #ah4--;,converter ,ready to ,dump4 8,my invention is based on the observation which ,i have made that if the lead ores to be desulphurized contain a sufficient quantity of limestone it is possible1 by observing certain precautions1 to dispense entirely with the previous roasting in a roasting furnace1 and to desulphurize the ores in one operation by blowing air through them4 ,i have found that the addition of limestone renders the roasting of the lead ore unnecessary1 because the limestone produces the following effects3 8,the particles of limestone act mechanically by separating the particles of lead ore from each other in such a way that premature agglomeration is prevented and the whole mass is loosened and rendered accessible to air2 and1 moreover1 the limestone moderates the high reaction temperature resulting from the burning of the sulphur1 so that the liquefaction of the galena1 the sublimation of lead sulphide1 and the separation of metallic lead are avoided4 ,the moderation of the temperature of reaction is caused by the decomposition of the limestone into caustic lime and carbon dioxide1 whereby a large amount of heat becomes latent4 ,further1 the decomposition of the limestone causes chemical reactions1 lime being formed1 which at the moment of its formation is partly converted into sulphate of lime at the expense of the sulphur contained in the ore1 and this sulphate of lime1 when the scorification takes place1 is transformed into calcium silicate by the silicic acid1 the sulphuric acid produced thereby escaping4 ,the limestone also largely contributes to the desulphurization of the ore1 as it causes the production of sulphuric acid at the expense of the sulphur of the ore1 which sulphuric acid is a powerful oxidizing agent4 ,if1 therefore1 a mixture of raw lead ore and limestone 7which mixture must1 of course1 contain a sufficient amount of silicic acid for forming silicates7 be introduced into a chamber and a current of air be blown through the mixture1 and at the same time the part of the mixture which is near the blast inlet be ignited1 the combustion of the sulphur will give rise to very energetic reactions1 and sulphurous acid1 sulphuric acid1 lead oxide1 sulphates and silicates are produced4 ,the sulphurous acid and the carbon dioxide escape1 while the sulphuric acid and sulphates act in their turn as oxidizing agents on the undecomposed galena4 ,part of the sulphates is decomposed by the silicic acid1 thereby liberating sulphuric acid1 which1 as already stated1 acts as an oxidizing agent4 ,the remaining lead oxide combines finally with the gangue of the ore and the non-volatile constituents of the flux 7the limestone7 to form the required slag4 ,these several reactions commence at the blast inlet at the bottom of the chamber1 and extend gradually toward the upper portion of the charge of ore and limestone4 ,liquefaction of the ores does not take place1 for although a slag is formed it is at once solidified by the blowing in of the air1 the passages formed thereby in the hardening slag allowing of the continued passage therethrough of the air4 ,the final product is a silicate consisting of lead oxide1 lime1 silicic acid1 and other constituents of the ore1 which now contains but little or no sulphur and constitutes a coherent solid mass1 which1 when broken into pieces1 forms a material suitable to be smelted4 8,the quantity of limestone required for the treatment of the lead ores varies according to the constitution of the ores4 ,it should1 however1 amount generally to from #ae to #bj per cent4 ,as lead ores do not contain the necessary amount of limestone as a natural constituent1 a considerable amount of limestone must be added to them1 and this addition may be made either during the dressing of the ores or subsequently4 8,for the satisfactory working of the process1 the following precautions are to be observed3 ,in order that the blowing in of the air may not cause particles of limestone to escape in the form of dust before the reaction begins1 it is necessary to add to the charge before it is subjected to the action in the chamber a considerable amount of water--say #e per cent4 or more4 ,this water prevents the escape of dust1 and it also contributes considerably to the formation of sulphuric acid1 which1 by its oxidizing action1 promotes the reaction1 and1 consequently1 also the desulphurization4 ,it is advisable1 in conducting the operation1 not to fill the chamber with the charge at once1 but first only partly to fill it and add to the charge gradually while the chamber is at work1 as by this means the reaction will take place more smoothly in the mass4 ,illustration3 ,fig4 #ai4--;,charge ,dumped4 8,it is advantageous to proceed as follows3 ,the bottom part of a chamber of any suitable form is provided with a grate1 on which is laid and ignited a mixture of fuel 7coal1 coke1 or the like7 and pieces of limestone4 ,by mixing the fuel with pieces of limestone the heating power of the fuel is reduced and the grate is protected1 while at the same time premature melting of the lower part of the charge is prevented2 or the grate may be first covered with a layer of limestone and the fuel be laid thereon1 and then another layer of limestone be placed on the fuel4 ,on the material thus placed in the chamber1 a uniform charge of lead ore and limestone--say about #ab in4 high--is placed1 this having been moistened as previously explained4 ,under the influence of the air-blast and the heat1 the reactions hereinbefore described take place4 ,when the upper surface of the first layer becomes red-hot1 a further charge is laid thereon1 and further charges are gradually introduced as the surface of the preceding charge becomes red-hot1 until the chamber is full4 ,so long as charges are still introduced a blast of air of but low pressure is blown through2 but when the chamber is filled a larger quantity of air at a higher pressure is blown through4 ,the scorification process then takes place1 a very powerful desulphurization having preceded it4 ,during the scorification the desulphurization is completed4 8,when the process is completed1 the chamber is tilted and the desulphurized mass falls out and is broken into small pieces for smelting40 ,the drawing on page #aij1 ,fig4 #ag1 shows a side view of the apparatus used in connection with the process1 which will be readily understood without special description4 ,the dotted lines show the pot in its emptying position4 ,the series of operations is clearly illustrated in ,figs4 #ah-bj1 which are reproduced from photographs4 ,this process has now been in practical use at ,ramsbeck for three years1 where it is employed for the desulphurization of galena of high grade in lead1 with which are mixed quartzose silver ore 7or sand if no such ore be available71 and calcareous and ferruginous fluxes4 ,a typical charge is #ajj parts of lead ore1 #aj parts of quartzose silver ore1 #aj parts of spathic iron ore1 and #ai parts of limestone4 ,a thorough mixture of the components is essential2 after the mixture has been effected1 the charge is thoroughly wetted with about #e per cent4 of water1 which is conceived to play a threefold function in the desulphurizing operation1 namely3 7#a7 preservation of the homogeneity of the mixture during the blowing2 7#b7 reduction of temperature during the process2 and 7#c7 formation of sulphuric acid in the process1 which promotes the desulphurization of the ore4 ,illustration3 ,,fig4 #ag4--,savelsberg ,converter4 ,the moistened charge is conveyed to the converters1 into which it is fed in thin layers4 ,the converters are hemispherical cast-iron pots1 supported by trunnions on a truck1 as shown in the accompanying engravings4 ,except for this method of support1 which renders the pot movable1 the arrangement is quite similar to that which is employed in the ,huntington-,heberlein process4 ,the pots which are now in use at ,ramsbeck have capacity for about #hjjj kg4 of charge1 but it is the intention of the management to increase the capacity to #aj1jjj or #ab1jjj kg4 ,previously1 pots of only #ejjj kg4 capacity were employed4 ,such a pot weighed #acjj kg41 exclusive of the truck4 ,the air-blast was about #g cu4 m4 7#bdg4b cu4 ft47 per min41 beginning at a pressure of #aj to #bj cm4 of water 7#b to #d oz47 and rising to #ej to #fj cm4 7#aa to #ac oz47 when the pot was completely filled with charge4 ,the desulphurization of a charge is completed in #ah hours4 ,a pot is attended by one man per shift of #ab hours2 this is only the attention of the pot proper1 the labor of conveying material to it and breaking up the desulphurized product being extra4 ,one man per shift should be able to attend to two pots1 which is the practice in the ,huntington-,heberlein plants4 ,illustration3 ,fig4 #bj4--;,converter in ,position for ,blowing4 ,when the operation in the pot is completed1 the latter is turned on its trunnions1 until the charge slides out by gravity1 which it does as a solid cake4 ,this is caused to fall upon a vertical bar1 which breaks it into large pieces4 ,by wedging and sledging these are reduced to lumps of suitable size for the blast furnace4 ,when the operation has been properly conducted the charge is reduced to about #b or #c per cent4 sulphur4 ,it is expected that the use of larger converters will show even more favorable results in this particular4 ,as in the ,huntington-,heberlein and ,carmichael-,bradford processes1 one of the greatest advantages of the ,savelsberg process is the ability to effect a technically high degree of desulphurization with only a slight loss of lead and silver1 which is of course due to the perfect control of the temperature in the process4 ,the precise loss of lead has not yet been determined1 but in the desulphurization of galena containing #fj to #gh per cent4 lead1 the loss of lead is probably not more than #a per cent4 ,there appears to be no loss of silver4 ,the process is applicable to a wide variety of lead-sulphide ores4 ,the ore treated at ,ramsbeck contains #fj to #gh per cent4 lead and about #ae per cent4 of sulphur1 but ore from ,broken ,hill1 ,new ,south ,wales1 containing #aj per cent4 of zinc has also been treated4 ,a zinc content up to #g or #h per cent4 in the ore is no drawback1 but ores carrying a higher percentage of zinc require a larger addition of silica and about #e per cent4 of iron ore in order to increase the fusibility of the charge4 ,the charge ordinarily treated at ,ramsbeck is made to contain about #aa per cent4 of silica4 ,the presence of pyrites in the ore is favorable to the desulphurization4 ,dolomite plays the same part in the process that limestone does1 but is of course less desirable1 in view of the subsequent smelting in the blast furnace4 ,the ore is best crushed to about #c mm4 size1 but good results have been obtained with ore coarser in size than that4 ,however1 the proper size is somewhat dependent upon the character of the ore4 ,the blast pressure required in the converter is also1 of course1 somewhat dependent upon the porosity of the charge4 ,fine slimes are worked up by mixture with coarser ore4 ,in making up the charge1 the proportion of limestone is not varied much1 but the proportions of silica and iron must be carefully modified to suit the ore4 ,certain kinds of ore have a tendency to remain pulverulent1 or to retain balls of unsintered1 powdered material4 ,in such cases it is necessary to provide more fusible material in the charge1 which is done by varying the proportions of silica and iron4 ,the charge must1 moreover1 be prepared in such a manner that overheating1 and consequently the troublesome fusion of raw galena1 will be avoided4 ,the essential difference between the ,huntington-,heberlein and ,savelsberg processes is the use in the former of a partially desulphurized ore1 containing lime and sulphate of lime2 and the use in the latter of raw ore and carbonate of lime4 ,it is claimed that the latter1 which loses its carbon dioxide in the converter1 necessarily plays a different chemical part from that of quicklime or gypsum4 ,irrespective of the reactions1 however1 the ,savelsberg process has the great economic advantage of dispensing with the preliminary roasting of the ,huntington-,heberlein process1 wherefore it is cheaper both in first cost of plant and in operation4 ,,the ,,lime-,,roasting ,,of ,,galena#cb ,,by ,,walter ,,renton ,,ingalls ,during the last two years1 and especially during the last six months1 a number of important articles upon the new methods for the desulphurization of galena have been published in the technical periodicals1 particularly in the ,engineering and ,mining ,journal and in ,metallurgie4 ,i proposed for these methods the type-name of 8lime-roasting of galena10 as a convenient metallurgical classification1#cc and this term has found some acceptance4 ,the articles referred to have shown the great practical importance of these new processes1 and the general recognition of their metallurgical and commercial value1 which has already been accorded to them4 ,it is my present purpose to review broadly the changes developed by them in the metallurgy of lead1 in which connection it is necessary to refer briefly to the previous state of the art4 ,the elimination of the sulphur content of galena has been always the most troublesome part of the smelting process1 being both costly in the operation and wasteful of silver and lead4 ,previous to the introduction of the ,huntington-,heberlein process at ,pertusola1 ,italy1 it was effected by a variety of methods4 ,in the treatment of non-argentiferous galena concentrate1 the smelting was done by the roast-reduction method 7roasting in reverberatory furnace and smelting in blast furnace72 the roast-reaction method1 applied in reverberatory furnaces2 and the roast-reaction method1 applied in ,scotch hearths4#cd ,precipitation smelting1 simple1 had practically gone out of use1 although its reactions enter into the modern blast-furnace practice1 as do also those of the roast-reaction method4 ,in the treatment of argentiferous lead ores1 a combination of the roast-reduction1 roast-reaction and precipitation methods had been developed4 ,ores low in lead were still roasted1 chiefly in hand-worked reverberatories 7the mechanical furnaces not having proved well adapted to lead-bearing ores71 while the high loss of lead and silver in sinter-or slag-roasting of rich galenas had caused those processes to be abandoned1 and such ores were charged raw into the blast furnace1 the part of their sulphur which escaped oxidation therein reappearing in the form of matte4 ,in the roast-reduction smelting of galena alone1 however1 there was no way of avoiding the roasting of the whole1 or at least a very large percentage of the ore1 and in this roasting the ore had necessarily to be slagged or sintered in order to eliminate the sulphur to a satisfactory extent4 ,this is exemplified in the treatment of the galena concentrate of southeastern ,missouri at the present time4 ,until the two new ,scotch-hearth plants at ,alton and ,collinsville1 ,ill41 were put in operation1 the three processes of smelting the southeastern ,missouri galena were about on an equal footing4 ,their results per ton of ore containing #fe per cent4 lead were approximately as follows#ce3 ,,method ,,cost ,,extraction ,reverberatory #f4ej-g4jj #ij-ib ,scotch hearth #e4ge-f4ej #hg-hh ,roast-reduction #f4jj-g4jj #ij-ib ,the new works employ the ,scotch-hearth process1 with bag-houses for the recovery of the fume1 which previously was the weak point of this method of smelting4#cf ,this improvement led to a large increase in the recovery of lead1 so that the entire extraction is now approximately #ih per cent4 of the content of the ore1 while on the other hand the cost of smelting per ton of ore has been reduced through the increased size of these plants and the introduction of improved means for handling ore and material4 ,the practice of these works represents the highest efficiency yet obtained in this country in the smelting of high-grade galena concentrate1 and probably it cannot be equaled even by the ,huntington-,heberlein and similar processes4 ,the ,scotch-hearth and bag-house process is therefore the one of the older methods of smelting which will survive4 ,in the other methods of smelting1 a large proportion of the cost is involved in the roasting of the ore1 which amounts in hand-worked reverberatory furnaces to #b to #b4ej per ton4 ,also1 the larger proportion of the loss of metal is suffered in the roasting of the ore1 this loss amounting to from #f to #h per cent4 of the metal content of such ore as is roasted4 ,the loss of lead in the combined process of treatment depends upon the details of the process4 ,the chief advantage of lime-roasting in the treatment of this class of ore is in the higher extraction of metal which it affords4 ,this should rise to #ih per cent4 ,that figure has been1 indeed1 surpassed in operations on a large scale1 extending over a considerable period4 ,in the treatment of the argentiferous ores of the ,west different conditions enter into the consideration4 ,in the working of those ores1 the present practice is to roast only those which are low in lead1 and charge raw into the blast furnace the rich galenas4 ,the cost of roasting is about #b to #b4ej per ton2 the cost of smelting is about #b4ej per ton4 ,on the average about #j4d ton of ore has to be roasted for every ton that is smelted4 ,the cost of roasting and smelting is therefore about #c4ej per ton4 ,in good practice the recovery of silver is about #ih per cent4 and of lead about #ie per cent41 reckoned on basis of fire assays4 ,in treatment of these ores1 the lime-roasting process offers several advantages4 ,it may be performed at less than the cost of ordinary roasting4#cg ,the loss of silver and lead during the roasting is reduced to insignificant proportion4 ,the sulphide fines which must be charged raw into the blast furnace are eliminated1 inasmuch as they can be efficiently desulphurized in the lime-roasting pots without significant loss2 all the ore to be smelted in the blast furnace can be1 therefore1 delivered to it in lump form1 whereby the speed of the blast furnace is increased and the wind pressure required is decreased4 ,finally1 the percentage of sulphur in the charge is reduced1 producing a lower matte-fall1 or no matte-fall whatever1 with consequent saving in expense of retreatment4 ,in the case of a new plant1 the first cost of construction and the ground-space occupied are materially reduced4 ,before discussing more fully the extent and nature of these savings1 it is advisable to point out the differences among the three processes of lime-roasting that have already come into practical use4 ,in the ,huntington-,heberlein process1 the ore is mixed with suitable proportions of limestone and silica 7or quartzose ore7 and is then partially roasted1 say to reduction of the sulphur to one half4 ,the roasting is done at a comparatively low temperature1 and the loss of metals is consequently small4 ,the roasted ore is dampened and allowed to cool4 ,it is then charged into a hemispherical cast-iron pot1 with a movable hood which covers the top and conveys off the gases4 ,there is a perforated grate in the bottom of the pot1 on which the ore rests1 and air is introduced through a pipe entering the bottom of the pot1 under the grate4 ,a small quantity of red-hot calcines from the roasting furnaces is thrown on the grate to start the reaction2 a layer of cold1 semi-roasted ore is put upon it1 the air blast is turned on and reaction begins1 which manifests itself by the copious evolution of sulphur fumes4 ,these consist chiefly of sulphur dioxide1 but they contain more or less trioxide1 which is evident from the solution of copperas that trickles from the hoods and iron smoke-pipes1 wherein the moisture condenses4 ,as the reaction progresses1 and the heat creeps up1 more ore is introduced1 layer by layer1 until the pot is full4 ,care is taken by the operator to compel the air to pass evenly and gently through the charge1 wherefore he is watchful to close blow-holes which develop in it4 ,at the end of the operation1 which may last from four to eighteen hours1 the ore becomes red-hot at the top4 ,the hood is then pushed up1 and the pot is turned on its trunnions1 by means of a hand-operated wheel and worm-gear1 until the charge slides out1 which it does as a solid1 semi-fused cake4 ,the pot is then turned back into position4 ,its design is such that the air-pipe makes automatic connection1 a flanged pipe cast with the pot settling upon a similarly flanged pipe communicating with the main1 a suitable gasket serving to make a tight joint4 ,the pots are set at an elevation of about #ab ft4 above the ground1 so that when the charge slides out the drop will break it up to some extent1 and it is moreover caused to fall on a wedge1 or similar contrivance1 to assist the breakage4 ,after cooling it is further broken up to furnace size by wedging and sledging2 the lumps are forked out1 and the fines screened and returned to a subsequent charge for completion of their desulphurization4 ,the ,savelsberg process differs from the ,huntington-,heberlein in respect to the preliminary roasting1 which in the ,savelsberg process is omitted1 the raw ore1 mixed with limestone and silica1 being charged directly into the converter4 ,the ,savelsberg converter is supported on a truck1 instead of being fixed in position1 but otherwise its design and management are quite similar to those of the ,huntington-,heberlein converter4 ,in neither case are there any patents on the converters4 ,the patents are on the processes4 ,in view of the litigation that has already been commenced between their respective owners1 it is interesting to examine the claims4 ,the ,huntington-,heberlein patent 7,u4 ,s4 #fjj1cdg1 issued ,march #h1 #ahih1 applied for ,dec4 #i1 #ahif7 has the following claims3 #a4 ,the herein-described method of oxidizing sulphide ores of lead preparatory to reduction to metal1 which consists in mixing with the ore to be treated an oxide of an alkaline-earth metal1 such as calcium oxide1 subjecting the mixture to heat in the presence of air1 then reducing the temperature and finally passing air through the mass to complete the oxidation of the lead1 substantially as and for the purpose set forth4 #b4 ,the herein-described method of oxidizing sulphide ores of lead preparatory to reduction to metal1 which consists in mixing calcium oxide or other oxide of an alkaline-earth metal with the ore to be treated1 subjecting the mixture in the presence of air to a bright-red heat 7about #gjj deg4 ,c471 then cooling down the mixture to a dull-red heat 7about #ejj deg4 ,c471 and finally forcing air through the mass until the lead ore1 reduced to an oxide1 fuses1 substantially as set forth4 #c4 ,the herein-described method of oxidizing lead sulphide in the preparation of the same for reduction to metal1 which consists in subjecting the sulphide to a high temperature in the presence of an oxide of an alkaline-earth metal1 such as calcium oxide1 and oxygen1 and then lowering the temperature substantially as set forth4 ,adolf ,savelsberg1 in ,u4 ,s4 patent #gee1eih 7issued ,march #bb1 #aijd1 applied for ,dec4 #ah1 #aijc7 claims3 #a4 ,the herein-described process of desulphurizing lead ores1 which consists in mixing raw ore with limestone and then subjecting the mixture to the simultaneous application of heat and a current of air in sufficient proportions to substantially complete the desulphurization in one operation1 substantially as described4 #b4 ,the herein-described process of desulphurizing lead ores1 which process consists in first mixing the ores with limestone1 then moistening the mixture1 then filling it without previous roasting into a chamber1 then heating it and treating it by a current of air1 as and for the purpose described4 #c4 ,the herein-described process of desulphurizing lead ores1 which consists in mixing raw ores with limestone1 then filling the mixture into a chamber1 then subjecting the mixture to the simultaneous application of heat and a current of air in sufficient proportions to substantially complete the desulphurization in one operation1 the mixture being introduced into the chamber in partial charges introduced successively at intervals during the process1 substantially as described4 #d4 ,the herein-described process of desulphurizing lead ores1 then moistening the mixture1 then filling it without previous roasting into a chamber1 then heating it and treating it by a current of air1 the mixture being introduced into the chamber in partial charges introduced successively at intervals during the process1 as and for the purpose described4 #e4 ,the herein-described process of desulphurizing lead ores1 which process consists in first mixing the ores with sufficient limestone to keep the temperature of the mixture below the melting-point of the ore1 then filling the mixture into a chamber1 then heating said mixture and treating it with a current of air1 as and for the purpose described4 #f4 ,the herein-described process of desulphurizing lead ores1 which process consists in first mixing the ores with sufficient limestone to mechanically separate the particles of galena sufficiently to prevent fusion1 and to keep the temperature below the melting-point of the ore by the liberation of carbon dioxide1 then filling the mixture into a chamber1 then heating said mixture and treating it with a current of air1 as and for the purpose described4 ,the ,carmichael-,bradford process differs from the ,savelsberg by the treatment of the raw ore mixed with gypsum instead of limestone1 and differs from the ,huntington-,heberlein both in respect to the use of gypsum and the omission of the preliminary roasting4 ,the ,carmichael-,bradford process has not been threatened with litigation1 so far as ,i am aware4 ,the claims of its original patent read as follows#ch3 #a4 ,the process of treating mixed sulphide ores1 which consists in mixing with said ores a sulphur compound of a metal of the alkaline earths1 starting the reaction by heating the same1 thereby oxidizing the sulphide and reducing the sulphur compound of the alkali metal1 passing a current of air to oxidize the reduced sulphide compound of the metal of the alkalies preparatory to acting upon a new charge of sulphide ores1 substantially as and for the purpose set forth4 #b4 ,the process of treating mixed sulphide ores1 which consists in mixing calcium sulphate with said ores1 starting the reaction by means of heat1 thereby oxidizing the sulphide ores1 liberating sulphurous-acid gas and converting the calcium sulphate into calcium sulphide and oxidizing the calcium sulphide to sulphate preparatory to treating a fresh charge of sulphide ores1 substantially as and for the purpose set forth4 ,the process described by ,w4 ,s4 ,bayston1 of ,melbourne 7,australian patent ,no4 #bhfb71 appears to be identical with that of ,savelsberg4 ,irrespective of the validity of the ,savelsberg and ,carmichael-,bradford patents1 and without attempting to minimize the ingenuity of their inventors and the importance of their discoveries1 it must be conceded that the merit for the invention and introduction of lime-roasting of galena belongs to ,thomas ,huntington and ,ferdinand ,heberlein4 ,the former is an ,american1 and this is the only claim that the ,united ,states can make to a share in this great improvement in the metallurgy of lead4 ,it is to be regretted1 moreover1 that of all the important lead-smelting countries in the world1 ,america has been the most backward in adopting it4 ,the details of the three processes and the general results accomplished by them have been rather fully described in a series of articles recently published in the ,engineering and ,mining ,journal4 ,there has been1 however1 comparatively little discussion as to costs2 and unfortunately the data available for analysis are extremely scanty1 due to the secrecy with which the ,huntington-,heberlein process1 the most extensively exploited of the three1 has been veiled4 ,nevertheless1 ,i may attempt an approximate estimation of the various details1 taking the ,huntington-,heberlein process as the basis4 ,the ore1 limestone and silica are crushed to pass a four-mesh screen4 ,this is about the size to which it would be necessary to crush as preliminary to roasting in the ordinary way1 wherefore the only difference in cost is the charge for crushing the limestone and silica1 which in the aggregate may amount to one-sixth of the weight of the raw sulphide and may consequently add #b to #b4e;c4 to the cost of treating a ton of ore4 ,the mixing of ore and fluxes may be costly or cheap1 according to the way of doing it4 ,if done in a rational way it ought not to cost more than #aj;c4 per ton of ore1 and may come to less4 ,the delivery of the ore from the mixing-house to the roasting furnaces ought to be done entirely by mechanical means1 at insignificant cost4 ,the ,heberlein roasting furnace1 which is used in connection with the ,h4-,h4 process1 is simply an improvement on the old ,brunton calciner--a circular furnace1 with revolving hearth4 ,the construction of this furnace1 according to ,american designs1 is excellent4 ,the hearth is #bf ft4 in diameter2 it is revolved at slow speed and requires about #a4e h4p4 ,a flange at the periphery of the hearth dips into sand in an annular trough1 thus shutting off air from the combustion chamber1 except through the ports designed for its admittance4 ,the mechanical construction of the furnace is workmanlike1 and the mechanism under the hearth is easy of access and comfortably attended to4 ,a #bf ft4 furnace roasts about #hj1jjj lb4 of charge per #bd hours4 ,in dealing with an ore containing #bj to #bb per cent4 of sulphur1 the latter is reduced to about #aj to #aa per cent41 the consumption of coal being about #bb4e per cent4 of the weight of the charge4 ,the hearth efficiency is about #aej lb4 per sq4 ft41 which in comparison with ordinary roasting is high4 ,the coal consumption1 however1 is not correspondingly low4 ,two furnaces can be managed by one man per #h hour shift4 ,on the basis of #hj tons of charge ore per #bd hours1 the cost of roasting should be approximately as follows3 ,labor--#c men at #b4ej #g4ej ,coal--#ah tons at #b #cf4jj ,power #c4ce ,repairs #c4ce ------------ ,total #ej4bj #fc;c4 per ton4 ,in the above estimate repairs have been reckoned at the same figure as is experienced with ,brckner cylinders1 and the cost of power has been allowed for with fair liberality4 ,the estimated cost of #fc;c4 per ton is comparable with the #a4aj to #a4de per ton1 which is the result of roasting in ,brckner cylinders in ,colorado1 reducing the ore to #d4e-f per cent4 sulphur4 ,the ,heberlein furnace is built up to considerable elevation above the ground level1 externally somewhat resembling the ,pearce turret furnace4 ,this serves two purposes3 7#a7 it affords ample room under the hearth for attention to the driving mechanism2 and 7#b7 it enables the ore to be discharged by gravity into suitable hoppers1 without the construction of subterranean gangways4 ,the ore discharges continuously from the furnace1 at dull-red heat1 into a brick bin1 wherein it is cooled by a water-spray4 ,periodically a little ore is diverted into a side bin1 in which it is kept hot for starting a subsequent charge in the converter4 ,the cooled ore is conveyed from the receiving bins at the roasting furnaces to hopper-bins above the converters4 ,if the tramming be done by hand the cost1 with labor at #be;c4 per hour1 may be approximately #ab4e;c4 per ton of ore1 but this should be capable of considerable reduction by mechanical conveyance4 ,the converters are hemispherical pots of cast iron1 #i ft4 in diameter at the top1 and about #d ft4 in depth4 ,they are provided with a circular1 cast-iron grate1 which is in4 thick and #f ft4 in diameter and is set and secured horizontally in the pot4 ,this grate is perforated with holes in4 in diameter1 #b in4 apart1 center to center1 and is similar to the ,wetherill grate employed in zinc oxide manufacture4 ,the pot itself is about #b in4 thick at the bottom1 thinning to about #a in4 at the rim4 ,it is supported on trunnions and is geared for convenient turning by hand4 ,the blast pipe which enters the pot at the bottom is #f in4 in diameter4 ,two roasting furnaces and six converters are rated nominally as a #ij ton plant4 ,this rating is1 however1 considerably in excess of the actual capacity1 at least on certain ores4 ,the time required for desulphurization in the converter apparently depends a good deal upon the character of the ore4 ,the six converters may be arranged in a single row1 or in two rows of three in each4 ,they are set so that the rim of the pot1 when upright1 is about #ab ft4 above the ground level4 ,a platform gives access to the pots4 ,one man per shift can attend to two pots4 ,his work consists in charging them1 which is done by gravity1 spreading out the charge evenly in the pot1 closing any blow-holes which may develop1 and at the end of the operation raising the hood 7which covers the pot during the operation7 and dumping the pot4 ,the work is easy4 ,the conditions under which it is done are comfortable1 both as to temperature and atmosphere4 ,reports have shown a great reduction in liability to lead-poisoning in the works where the ,h4-,h4 process has been introduced4 ,a new charge is started by kindling a small wood or coal fire on the grate1 then throwing in a few shovelfuls of hot calcines1 and finally dropping in the regular charge of damp ore 7plus the fluxes previously referred to74 ,the charge is introduced in stages1 successive layers being dropped in and spread out as the heat rises4 ,at the beginning the blast is very low--about #b oz4 ,it is increased as the hight of the ore in the pot rises1 finally attaining about #af oz4 ,the operation goes on quietly1 the smoke rising from the surface evenly and gently1 precisely as in a well-running blast furnace4 ,while the charge is still black on top1 the hand can be held with perfect comfort1 inside of the hood1 immediately over the ore4 ,this explains1 of course1 why the volatilization of silver and lead is insignificant4 ,there is1 moreover1 little or no loss of ore as dust1 because the ore is introduced damp1 and the passage of the air through it is at low velocity4 ,in the interior of the charge1 however1 there is high temperature 7evidently much higher than has been stated in some descriptions71 as will be shown further on4 ,the conditions in this respect appear to be analogous to those of the blast furnace1 which1 though smelting at a temperature of say #abjj deg4 ,c4 at the level of the tuyeres1 suffers only a slight loss of silver and lead by volatilization4 ,at the end of the operation in the ,h4-,h4 pot1 the charge is dull red at the top1 with blow-holes1 around which the ore is bright red4 ,imperfectly worked charges show masses of well-fused ore surrounded by masses of only partially altered ore1 a condition which may be ascribed to the irregular penetration of air through the charge1 affording good evidence of the important part which air plays in the process4 ,a properly worked charge is tipped out of the pot as a solid cake1 which in falling to the ground breaks into a few large pieces4 ,as they break1 it appears that the interior of the charge is bright red all through1 and there is a little molten slag which runs out of cavities1 presumably spots where the chemical action has been most intense4 ,when cold1 the thoroughly desulphurized material has the appearance of slag-roasted galena4 ,prills of metallic lead are visible in it1 indicating reaction between lead sulphide and lead sulphate4 ,the columns of the structure supporting the pots should be of steel1 since fragments of the red-hot ore dumped on the ground are likely to fall against them4 ,to hasten the cooling of the ore1 water is sometimes played on it from a hose4 ,this is bad1 since some is likely to splash into the still inverted pot1 leading to cracks4 ,the cracked pots at certain works appear to be due chiefly to this cause1 in the absence of which the pots ought to last a long time1 inasmuch as the conditions to which they are subjected during the blowing process are not at all severe4 ,when the ore is sufficiently cold it is further broken up1 first by driving in wedges1 and finally by sledging down to pieces of orange size1 or what is suitable for the blast furnace4 ,these are forked out1 leaving the fine ore1 which comes largely from the top of the charge and is therefore only partially desulphurized4 ,the fines are1 therefore1 re-treated with a subsequent charge4 ,the quantity is not excessive2 it may amount to #g or #h per cent4 of the charge4 ,the breaking up of the desulphurized ore is one of the problems of the process1 the necessity being the reduction of several large pieces of fused1 or semi-fused1 material weighing two or three tons each4 ,when done by hand only1 as is usually 7perhaps always7 the practice1 the operation is rather expensive4 ,it would appear1 however1 to be not a difficult matter to devise some mechanical aids for this process--perhaps to make it entirely mechanical4 ,when done by hand1 a #f-pot plant requires #f men per shift sledging and forking4 ,with #h-;hour shifts1 this is #ah men for the breaking of about #fj tons of material1 which is about #c tons per man per #h hours4 ,with labor at #be;c4 per hour1 the cost of breaking the fused material comes to #fj;c4 per ton4 ,it may be remarked1 for comparison1 that in breaking ore as it ordinarily comes1 coarse and fine together1 a good workman would normally be expected to break #e to #e4e tons in a shift of #h hours4 ,the ordinary charge for the standard converter is about #h tons 7#af1jjj lb47 of an ore weighing #aff lb4 per cu4 ft4 ,with a heavier ore1 like a high-grade galena1 the charge would weigh proportionately more4 ,the time of working off a charge is decidedly variable4 ,accounts of the operation of the process in ,australia tell of charge-workings in #c to #e hours1 but this does not correspond with the results reported elsewhere1 which specify times of #ab to #ah hours4 ,assuming an average of #af hours1 which was the record of one plant1 six converters would have capacity for about #gb tons of charge per #bd hours1 or about #eh tons of ore1 the ratio of ore to flux being #d3a4 ,the loss in weight of the charge corresponds substantially to the replacement of sulphur by oxygen1 and the expulsion of carbon dioxide4 ,the finished charge contains on the average from #c to #e per cent4 sulphur4 ,this is about the same as the result achieved in good practice in roasting lead-bearing ores in hand-worked reverberatory furnaces1 but curiously the ,h4-,h4 product1 in some cases at least1 does not yield any matte1 to speak of1 in the blast furnace2 the product delivered to the latter being evidently in such condition that the remaining sulphur is almost completely burned off in the blast furnace4 ,this is an important saving effected by the process4 ,in calculating the value of an ore1 sulphur is commonly debited at the rate of #be;c4 per unit1 which represents approximately the cost of handling and reworking the matte resulting from it4 ,the practically complete elimination of matte-fall rendered possible by the ,h4-,h4 process may not be1 however1 an unmixed blessing4 ,there may be1 for example1 a small formation of lead sulphide which causes trouble in the crucible and lead-well1 and results in furnace difficulties and the presentation of a vexatious between-product4 ,it may now be attempted to summarize the cost of the converting process4 ,assuming the case of an ore assaying lead1 #ej per cent42 iron1 #ae2 sulphur1 #bb2 silica1 #h1 and alumina1 etc41 #e1 let it be supposed that it is to be fluxed with pure limestone and pure quartz1 with the aim to make a slag containing silica1 #cj2 ferrous oxide1 #dj2 and lime1 #bj per cent4 ,a ton of ore will make1 in round numbers1 #ajjj lb4 of slag1 and will require #cdd lb4 of limestone and #acj lb4 of quartz1 or we may say roughly one ton of flux must be added to four tons of ore1 wherefore the ore will constitute #hj per cent4 of the charge4 ,in reducing the charge to #c per cent4 sulphur it will lose ultimately through expulsion of sulphur and carbon dioxide 7of the limestone7 about #bj per cent4 in weight1 wherefore the quantity of material to be smelted in the blast furnace will be practically equivalent to the raw sulphide ore in the charge for the roasting furnaces2 but in the roasting furnace the charge is likely to gain weight1 because of the formation of sulphates4 ,taking the charge1 which ,i have assumed above1 and reckoning that as it comes from the roasting furnace it will contain #aj per cent4 sulphur1 all in the form of sulphate1 either of lead or of lime1 and that the iron be entirely converted to ferric oxide1 in spite of the expulsion of the carbon dioxide of the limestone and the combustion of a portion of the sulphur of the ore as sulphur dioxide1 the charge will gain in weight in the ratio of #a3a4ai4 ,this1 however1 is too high1 inasmuch as a portion of the sulphur will remain as sulphide while a portion of the iron may be as ferrous oxide4 ,the actual gain in weight will consequently be probably not more than one-tenth4 ,the following theoretical calculation will illustrate the changes3 ,,raw ,,charge ,,semi-,,roasted ,,charge ,,finished ,,charge #ajjj lb4 ,pb #aaed lb4 ,pb,o #aaed lb4 ,pb,o #cjj lb4 ,fe #dbh lb4 ,fe,o #dbh lb4 ,fe,o787 ,ore #afj lb4 ,si,o ,ore #afj lb4 ,si,o ,ore #afj lb4 ,si,o #ajj lb4 ,al,o1 #ajj lb4 ,al,o1 #ajj lb4 ,al,o1 etc4 etc4 etc4 #ddj lb4 ,s #cjj lb4 ,s #fh lb4 ,s #acj lb4 ,si,o #acj lb4 ,si,o #acj lb4 ,si,o ,flux #cdd lb4 ,ca,c,o ,flux #aic lb4 ,ca,o ,flux #aic lb4 ,ca,o #dej lb4 ,o -------- -------- -------- #bdgd lb4 #biae lb4 #bbcc lb4 #aj ,s4 #c ,s4 ,ratios3 #bdgd3biae 33 #a3a4ah4 #biae3bbcc 33 #a3j4gf4 #bdgd3bbcc 33 #a3j4ij4 ,it may be assumed that for every ton of charge 7containing about #hj per cent4 of ore7 there will be #a4a ton of material to go to the converter1 and that the product of the latter will be #j4i of the weight of the original charge of raw material4 ,each converter requires #djj cu4 ft4 of air per minute4 ,the blast pressure is variable1 as different pots are always at different stages of the process1 but assuming the maximum of #af oz4 pressure1 with a blast main of sufficient diameter 7at least #ae in47 and the blower reasonably near the battery of pots1 the total requirement is #ba h4p4 ,the cost of converting will be approximately as follows3 ,labor1 #c foremen at #c4bj #i4fj 8 #i men at #b4ej #bb4ej ,power1 #ba h4p4 at #cj;c #f4cj ,supplies1 repairs and renewals #e4jj ------------ ,total #dc4dj #fj;c4 per ton of charge4 ,the cost of converting is1 of course1 reduced directly as the time is reduced4 ,the above estimate is based on unfavorable conditions as to time required for working a charge4 ,the total cost of treatment1 from the initial stage to the delivery of the desulphurized ore to the blast furnaces1 will be1 per #bjjj lb4 of charge1 approximately as follows3 ,crushing #a4j ton at #aj;c #j4aj ,mixing #a4j ton at #aj;c 4#aj ,roasting #a4j ton at #fc;c 4#fc ,delivering #a4a ton to converters at #ab;c 4#ac ,converting #a4a ton at #fj;c 4#ff ,breaking #j4i ton at #fj;c 4#ed ---------- ,total #b4af ,the cost per ton of ore will be #b4af #j4hj #b4gj4 ,making allowance for the crushing of the ore1 which is not ordinarily included in the cost of roasting1 and possibly some overestimates1 it appears that the cost of desulphurization by this method1 under the conditions assumed in this paper1 is rather higher than in good practice with ordinary hand-worked furnaces1 but it is evident that the cost can be reduced to approximately the same figure by introduction of improvements1 as for example in breaking the desulphurized ore1 and by shortening the time of converting1 which is possible in the case of favorable ores4 ,the chief advantage must be1 however1 in the further stage of the smelting4 ,as to this1 there is the evidence that the ,broken ,hill ,proprietary ,company was able to smelt the same quantity of ore in seven furnaces1 after the introduction of the ,huntington-,heberlein process1 that formerly required thirteen4 ,a similar experience is reported at ,friedrichshtte1 ,silesia4 ,this increase in the capacity of the blast furnace is due to three things3 7#a7 ,in delivering to the furnace a charge containing a reduced percentage of fine ore1 the speed of the furnace is increased1 i4e41 more tons of ore can be smelted per square foot of hearth area4 7#b7 ,there is less roasted matte to go into the charge4 7#c7 ,under some conditions the percentage of lead in the charge can be increased1 reducing the quantity of gangue that must be fluxed4 ,it is difficult to generalize the economy that is effected in the blast-furnace process1 since this must necessarily vary within wide limits because of the difference in conditions4 ,an increase of #fj to #ajj per cent4 in blast-furnace capacity does not imply a corresponding reduction in the cost of smelting4 ,the fuel consumption per ton of ore remains the same4 ,there is a saving in the power requirements1 because the smelting can be done with a lower blast pressure2 also1 a saving in the cost of reworking matte4 ,there will1 moreover1 be a saving in other labor1 in so far as portions thereof are not already performed at the minimum cost per ton4 ,the net result under ,american conditions of silver-lead smelting can only be determined closely by extensive operations4 ,that there will be an important saving1 however1 there is no doubt4 ,the cost of smelting a ton of charge at ,denver and ,pueblo1 exclusive of roasting and general expense1 is about #b4ej1 of which about #j4hd is for coke and #a4ff for labor1 power and supplies4 ,general expense amounts to about #j4af additional4 ,if it should prove possible to smelt in a given plant #ej per cent4 more ore than at present without increase in the total expense1 except for coke1 the saving per ton of charge would be #gj;c4 ,that is not to be expected1 but the half of it would be a satisfactory improvement4 ,with respect to sulphur in the charge1 the cost is commonly reckoned at #be;c4 per unit4 ,as compared with a charge containing #b per cent4 of sulphur there would be a saving rising toward #ej;c4 per ton as the maximum4 ,it is reasonable to reckon1 therefore1 a possible saving of #ge;c4 per ton of charge in silver-lead smelting1 no saving in the cost of roasting1 and an increase of about #c per cent4 in the extraction of lead1 and perhaps #a per cent4 in the extraction of silver1 as the net results of the application of the ,huntington-,heberlein process in ,american silver-lead smelting4 ,on a charge averaging #ab per cent4 lead and #cc oz4 silver per ton1 an increase of #c per cent4 in the extraction of lead and #a per cent4 in the extraction of silver would correspond to #be;c4 and #ce;c4 respectively1 reckoning lead at #c4e;c4 per lb41 and silver at #fj;c4 per oz4 ,in this1 however1 it is assumed that all lead-bearing ores will be desulphurized by this process1 which practically will hardly be the case4 ,a good deal of pyrites1 containing only a little lead1 will doubtless continue to be roasted in ,brckner cylinders1 and other mechanical furnaces1 which are better adapted to the purpose than are the lime-roasting pots4 ,moreover1 a certain proportion of high-grade lead ore1 which is now smelted raw1 will be desulphurized outside of the furnace1 at additional expense4 ,it is comparatively simple to estimate the probable benefit of the ,huntington-,heberlein process in the case of smelting works which treat principally a single class of ore1 but in such works as those in ,colorado and ,utah1 which treat a wide variety of ores1 we must anticipate a combination process1 and await results of experience to determine just how it will work out4 ,it should be remarked1 moreover1 that my estimates do not take into account the royalty on the process1 which is an actual debit1 whether it be paid on a tonnage basis or be computed in the form of a lump sum for the license to its use4 ,however1 in view of the immense tonnage of ore smelted annually for the extraction of silver and lead1 it is evident that the invention of lime-roasting by ,huntington and ,heberlein was an improvement of the first order in the metallurgy of lead4 ,in the case of non-argentiferous galena1 containing #fe per cent4 of lead 7as in southeastern ,missouri71 comparison may be made with the slag-roasting and blast-furnace smelting of the ore4 ,here1 no saving in cost of roasting may be reckoned and no gain in the speed of the blast furnaces is to be anticipated4 ,the only savings will be in the increase in the extraction of lead from #ib to #ih per cent41 and the elimination of matte-roasting1 which latter may be reckoned as amounting to #ej;c4 per ton of ore4 ,the extent of the advantage over the older method is so clearly apparent that it need not be computed any further4 ,in comparison with the ,scotch-hearth bag-house method of smelting1 however1 the advantage1 if any1 is not so certain4 ,that method already saves #ih per cent4 of the lead1 and on the whole is probably as cheap in operation as the ,huntington-,heberlein could be under the same conditions4 ,the ,huntington-,heberlein method has replaced the old roast-reaction method at ,tarnowitz1 ,silesia1 but the ,american ,scotch-hearth method as practised near ,st4 ,louis is likely to survive4 ,a more serious competitor will be1 however1 the ,savelsberg process1 which appears to do all that the ,huntington-,heberlein process does1 without the preliminary roasting4 ,indeed1 if the latter be omitted 7together with its estimated expense of #fc;c4 per ton of charge1 or #gi;c4 per ton of ore71 all that has been said in this paper as to the ,huntington-,heberlein process may be construed as applying to the ,savelsberg4 ,the charge is prepared in the same way1 the method of operating the converters is the same1 and the results of the reactions in the converters are the same4 ,the litigation which is pending between the two interests1 ,messrs4 ,huntington and ,heberlein claiming that ,savelsberg infringes their patents1 will be1 however1 a deterrent to the extension of the ,savelsberg process until that matter be settled4 ,the ,carmichael-,bradford process may be dismissed with a few words4 ,it is similar to the ,savelsberg1 except that gypsum is used instead of limestone4 ,it is somewhat more expensive because the gypsum has to be ground and calcined4 ,the process works efficiently at ,broken ,hill1 but it can hardly be of general application1 because gypsum is likely to be too expensive1 except in a few favored localities4 ,the ability to utilize the converter gases for the manufacture of sulphuric acid will cut no great figure1 save in exceptional cases1 as at ,broken ,hill1 and anyway the gases of the other processes can be utilized for the same purpose1 which is in fact being done in connection with the ,huntington-,heberlein process in ,silesia4 ,the cost of desulphurizing a ton of galena concentrate by the ,carmichael-,bradford process is estimated by the company controlling the patents as follows1 labor being reckoned at #a4hj per eight hours1 gypsum at #b4dj per #bbdj lb41 and coal at #h4dj per #bbdj lb43 #j4be ton of gypsum #j4fj ,dehydrating and granulating gypsum 4#dh ,drying mixture of ore and gypsum 4#ab ,converting #j4bd ,spalling sintered material 4#ab #j4ja ton coal 4#jh ---------- ,total #a4fd ,the value of the lime in the sintered product is credited at #ab;c41 making the net cost #a4eb per #bbdj lb4 of ore4 ,the cost allowed for converting may be explained by the more rapid action that appears to be attained with the ores of ,broken ,hill than with some ores that are treated in ,north ,america1 but the low figure estimated for spalling the sintered material appears to be highly doubtful4 ,the theory of the lime-roasting processes is not yet well established4 ,it is recognized that the explanation offered by ,huntington and ,heberlein in their original patent specification is erroneous4 ,there is no good evidence in their process1 or any other1 of the formation of the higher oxide of lime1 which they suggest4 ,at the present time there are two views4 ,in one1 formulated most explicitly by ,professor ,borchers1 there is formed in this process a plumbate of calcium1 which is an active oxidizing agent4 ,a formation of this substance was also described by ,carmichael in his original patent1 but he considered it to be the final product1 not the active oxidizing agent4 ,in the other view1 the lime1 or limestone1 serves merely as a diluent of the charge1 enabling the air to obtain access to the particles of galena1 without liquefaction of the latter4 ,the oxidation of the lead sulphide is therefore effected chiefly by the air1 and the process is analogous to what takes place in the bessemer converter or in the ,germot process of smelting1 or perhaps more closely to what might happen in an ordinary roasting furnace1 provided with a porous hearth1 through which the air supply would be introduced4 ,roasting furnaces of that design have been proposed1 and in fact such a construction is now being tested for blende roasting in ,kansas4 ,up to the present time1 the evidence is surely too incomplete to enable a definite conclusion to be reached4 ,some facts may1 however1 be stated4 ,there is clearly reaction to a certain extent between lead sulphide and lead sulphate1 as in the reverberatory smelting furnace1 because prills of metallic lead are to be observed in the lime-roasted charge4 ,there is a formation of sulphuric acid in the lime-roasting1 upon the oxidizing effect of which ,savelsberg lays considerable stress1 since its action is to be observed on the iron work in which it condenses4 ,calcium sulphate1 which is present in all of the processes1 being specifically added in the ,carmichael-,bradford1 evidently plays an important chemical part1 because not only is the sulphur trioxide expelled from the artificial gypsum1 but also it is to a certain extent expelled from the natural gypsum1 which is added in the ,carmichael-,bradford process2 in other words1 more sulphur is given off by the charge than is contained by the metallic sulphides alone4 ,further evidence that lime does indeed play a chemical part in the reaction is presented by the phenomena of lime-roasting in clay dishes in the assay muffle1 wherein the air is certainly not blown through the charge1 which is simply exposed to superficial oxidation as in ordinary roasting4 ,the desulphurized charge dropped from the pot is certainly at much below the temperature of fusion1 even in the interior1 but we have no evidence of the precise temperature condition during the process itself4 ,pyrite and even zinc blende in the ore are completely oxidized4 ,this1 at least1 indicates intense atmospheric action4 ,the papers by ,borchers1#ci ,doeltz1#dj ,guillemain1#da and ,hutchings#db may profitably be studied in connection with the reactions involved in lime-roasting4 ,the conclusion will be1 however1 that their precise nature has not yet been determined4 ,in view of the great interest that has been awakened by this new departure in the metallurgy of lead1 it is to be expected that much experimental work will be devoted to it1 which will throw light upon its principles1 and possibly develop it from a mere process of desulphurization into one which will yield a final product in a single operation4 ,,part ,,vi ,,other ,,methods ,,of ,,smelting ,,the ,,bormettes ,,method ,,of ,,lead ,,and ,,copper ,,smelting#dc ,,by ,,alfredo ,,lotti 7,september #cj1 #aije7 ,it is well known that1 in order to obtain a proper fusion in lead and copper ore-smelting1 it is not only advantageous1 but often indispensable1 that a suitable proportion of slag be added to the charge4 ,in the treatment of copper matte in the converter1 the total quantity of slag must be resmelted1 inasmuch as it always retains a notable quantity of the metal2 while in the smelting of lead ore in the blast furnace1 the addition of slag is mainly intended to facilitate the operation1 avoiding the use of strong air pressure and thus diminishing the loss of lead4 ,the proportion of slag required sometimes amounts to #cj to #ce per cent4 of the weight of the ore4 ,inasmuch as the slag is usually added in lump form1 cold1 its original heat 7about #djj calories per kilogram7 is completely lost and an intimate mixture with the charge cannot be obtained4 ,for this reason1 ,i have studied the agglomeration of lead and copper ores with fused slag1 employing a variable proportion according to the nature of the ore treated4 ,in the majority of cases1 and with some slight modifications in each particular case1 by incorporating the dry or slightly moistened mineral with the predetermined quantity of liquid slag1 and by rapidly stirring the mixture so as to secure a proper subdivision of the slag and the mineral1 there is produced a spongy material1 largely composed of small pieces1 together with a simultaneous evolution of dense fumes of sulphur1 sulphur dioxide1 and sulphur trioxide4 ,by submitting this spongy material to an air blast1 the sulphur of the mineral is burned1 the temperature rising in the interior of the mass to a clear red heat4 ,copious fumes of sulphur dioxide and trioxide are given off1 and at times a yellowish vapor of sulphur1 which condenses in drops1 especially if the ore is pyritous4 ,at the end of from one to three hours1 according to the quantity of sulphur contained in the material under treatment and the amount of the air pressure1 the desulphurization of the ore1 so far as it has come in contact with the air1 is completed1 and the mass1 now thoroughly agglomerated1 forms a spongy but compact block4 ,it is then only necessary to break it up and smelt it with the requisite quantity of flux and coke4 ,the physical condition of the material is conducive to a rapid and economical smelting1 while the mixture of the sulphide1 sulphate and oxide leads to a favorable reaction in the furnace4 ,in employing this method1 it sometimes happens that ores rich in sulphur produce during the smelting a little more matte than when the ordinary system of roasting is employed4 ,in such instances1 in order to avoid or to diminish the cost of re-treatment of the matte1 it is best to agglomerate a portion thereof with the crude mineral and the slag4 ,this has the advantage of oxidizing the matte1 which acts as a ferruginous flux in the smelting4 ,the system described above leads to considerable economy1 especially in roasting1 as the heat of the scoria1 together with that given off in the combustion of the sulphur1 is almost always sufficient for the agglomeration and desulphurization of the mineral2 while1 moreover1 it reduces the cost of smelting in the blast furnace4 ,although the primary desulphurization is only partial 7about #ej per cent471 it continues in the blast furnace1 since the mineral1 agglomerated with the slag1 assumes a spongy form and thereby presents an increased surface to the action of the air4 ,the sulphur also acts as a fuel and does not produce an excessive quantity of matte4 ,the system will prove especially useful in the treatment of argentiferous lead ore1 since1 by avoiding the calcination in a reverberatory furnace1 loss of silver is diminished4 ,it appears1 however1 that1 contrary to the reactions which occur in the ,huntington-,heberlein process1 a calcareous or basic gangue is not favorable to this process1 if the proportion be too great4 ,the following comparison has been made in the case of an ore containing #fb to #fe per cent4 of lead1 #af to #ag per cent4 sulphur1 #aj to #aa per cent4 zinc1 #j4d per cent4 copper1 and #j4bbb per cent4 silver1 in which connection it is to be remarked that1 in general1 the less zinc there is in the ore the better are the results4 ,illustration3 ,,fig4 #ba4--;,elevation and ,plan of ,converting ,chambers4 ,ordinary ,method4--,roast-reduction4 ,cost per #ajjj kg4 of crude ore3 #a4 ,roasting in reverberatory furnace3 ,labor #j4gj ,fuel #a4ej ,repairs and supplies 4#je --------- #b4be #b4 ,smelting in water-jacket3 ,labor #a4ja ,fuel #b4bj ,repairs and supplies 4#jc ,fluxes 4#ej --------- #c4gd --------- ,total #e4ii ,bormettes ,method4--,agglomeration with slag1 pneumatic desulphurization and smelting in water-jacket3 #a4 ,agglomeration and desulphurization3 ,labor #j4db ,repairs and supplies #j4je ------- #j4dg #b4 ,smelting in water-jacket3 ,labor #j4ij ,fuel #a4ia ,repairs and supplies 4#jc ,fluxes 4#db --------- #c4bf --------- ,total #c4gc ,this shows a difference in favor of the new method of #b4bf per ton of ore1 without taking into account the savings realized by a much more speedy handling of the operation1 which would further reduce the cost to approximately #b4ej per ton4 ,illustration3 ,,fig4 #bb4--;,details of ,transfer ,cars4 ,in the above figures1 no account has been taken of general expenses1 which per ton of ore are reduced because of the greater rapidity of the process1 enabling a larger quantity of ore to be smelted in a given time4 ,making allowance for this1 the saving will amount to an average of #b4dj per #ajjj kg41 a figure which will naturally vary according to the prices for fuel1 labor1 and the quantity of matte which it may be necessary to re-treat4 ,if the quantity of matte does not exceed #aj per cent4 of the weight of the ore1 it can be desulphurized by admixture with the ore1 without use of other fuel4 ,if1 however1 the proportion of matte rises to #bj parts per #ajj parts of ore 7a maximum which ought not to be reached in good working71 it is necessary to roast a portion of it4 ,under unfavorable conditions1 consequently1 the saving effected by this process may be reduced to #b #b4bj per #ajjj kg41 and even to as little as #a4dj #a4fj4 ,the above reckonings are1 however1 without taking any account of the higher extraction of lead and silver1 which is one of the great advantages of the ,bormettes process4 ,illustration3 ,,fig4 #bc4--,latest ,form of ,converter4 7,section on ,a ,b47 ,the technical results obtained in the smelting of an ore of the above mentioned composition are as follows3 ,,ordinary ,,bormettes ,,method ,,method ,coke1 per cent4 of the charge #ad #ab ,blast pressure1 water gage #ab to #bj cm4 #ab to #ad cm4 ,tons of charge smelted per #bd hr #bj #be ,tons of ore smelted per #bd hr #h #aj ,lead assay of slag #j4hj to #j4ijj4bj to #j4dj ,matte-fall1 per cent4 of ore charged #e to #aj #aj to #ae ,lead extraction #ij #ib ,silver extraction #ie #ih ,illustration3 ,,fig4 #bd4--,latest ,form of ,converter4 7,section on ,c ,d47 ,the higher extractions of lead and silver are explained by the fact that the loss of metals in roasting is reduced1 while1 moreover1 the slags from the blast furnace are poorer than in the ordinary process of smelting4 ,the economy in coke results from the greater quantity of sulphur which is utilized as fuel1 and from the increased fusibility of the charge for the blast furnace4 ,the new system of desulphurization enables the charge to be smelted with a less quantity of fresh flux1 by the employment in its place of a greater proportion of foul slag4 ,the reduction in the necessary amount of flux is due not only to the increased fusibility of the agglomerated charge1 but principally to the fact that in this system the formation of silicates of lead 7which are produced abundantly in ordinary slag-roasting7 is almost nil4 ,it is therefore unnecessary to employ basic fluxes in order to reduce scorified lead4 ,illustration3 ,,fig4 #be4--,latest ,form of ,converter4 7,plan47 ,the losses of metal in the desulphurization are less than in the ordinary method1 because the crude mineral remains only a short time 7from one to three hours7 in the apparatus for desulphurization and agglomeration1 and the temperature of the process is lower4 ,the blast-furnace slags are poorer1 because there is no formation of silicate of lead during the agglomeration4 ,the ,bormettes method1 in so far as the treatment of lead ore is concerned1 may be considered a combination process of roast-reaction1 of roast-reduction1 and of precipitation-smelting4 ,it is not1 however1 restricted to the treatment of lead ore4 ,it may also be applied to the smelting of pyritous copper-bearing ores4 ,in an experiment with cupriferous pyrites1 containing #bj to #be per cent4 sulphur1 it succeeded in agglomerating and smelting them without use of any fuel for calcination1 effecting a perfect smelting1 analogous to pyrite smelting1 with the production of a matte of sufficient degree of concentration4 ,the first cost of plant installation is very much reduced by the ,bormettes method1 inasmuch as the ordinary roasting furnaces are almost entirely dispensed with1 apparatus being substituted for them which cost only one-third or one-fourth as much as ordinary furnaces4 ,the process presents the advantage1 moreover1 of being put into immediate operation1 without any expenditure of excess fuel4 ,the apparatus required in the process is illustrated in ,figs4 #ba-be4 ,the apparatus for desulphurization and agglomeration consists of a cast-iron box1 composed of four vertical walls1 of which two incline slightly toward the front4 ,these inclined walls carry the air-boxes4 ,the other two walls are formed1 the one in front by the doors which give access to the interior1 and the other in the rear by a straight plate4 ,the whole arrangement is surmounted by a hood4 ,the four pieces when assembled form a box without bottom4 ,several of these boxes are combined as a battery4 ,the pots in which the agglomeration and desulphurization are effected are moved into these boxes on suitable cars1 in the manner shown in the first engraving4 ,a later and more improved form is shown1 however1 in ,figs4 #bc-be4 ,this process1 which is the invention of ,a4 ,lotti and has been patented in all the principal countries1 is in successful use at the works of the ,socit ,anonyme des ,mines de ,bormettes1 at ,bormettes1 ,la ,londe 7,var71 ,france4 ,negotiations are now in progress with respect to its introduction elsewhere in ,europe4 ,,the ,,germot ,,process#dd ,,by ,,walter ,,renton ,,ingalls 7,november #a1 #aijb7 ,according to ,f4 ,laur1 in the ,echo des ,mines 7these notes are abstracted from ,oest4 ,zeit41 ,l41 xl1 #ee1 ,october #d1 #aijb71 ,a4 ,germot1 of ,clichy1 ,france1 made experiments some years ago upon the production of white lead directly from galena4 ,these led ,catelin to attempt the recovery of metallic lead in a similar way4 ,if air be blown in proper quantity into a fused mass of lead sulphide the following reaction takes place3 #b,pb,s #b,o ,,so ,pb ,pb,s4 ,thus one-half of the lead is reduced1 and it is found collects all the silver of the ore2 the other half is sublimed as lead sulphide1 which is free from silver4 ,the reaction is exothermic to the extent that the burning of one-half the sulphur of a charge should theoretically develop sufficient heat to volatilize half of the charge and smelt the other half4 ,this is almost done in practice with very rich galena1 but not so with poorer ore4 ,the temperature of the furnace must be maintained at about #aajj deg4 ,c4 throughout the whole operation1 and there are the usual losses of heat by radiation1 absorption by the nitrogen of the air1 etc4 ,deficiencies in heat are supplied by burning some of the ore to white lead1 which is mixed with the black fume 7,pb,s7 and by the well-known reactions reduced to metal with evolution of sulphur dioxide4 ,the final result is therefore the production of 7#a7 pig lead enriched in silver2 7#b7 pig lead free from silver2 7#c7 a leady slag2 and 7#d7 sulphur dioxide4 ,in the case of ores containing less than #ge per cent4 ,pb the gangue forms first a little skin and then a thick hard crust which soon interferes with the operation1 especially if the ore be zinkiferous4 ,this difficulty is overcome by increasing the temperature or by fluxing the ore so as to produce a fusible slag4 ,a leady slag is always easily produced2 this is the only by-product of the process4 ,the theoretical reaction requires #fjj cu4 m4 of air1 assuming a delivery of #ej per cent4 from the blower1 and at one atmosphere pressure involves the expenditure of #ah h4p4 per #ajjj kg4 of galena per hour4 ,illustration3 ,,fig4 #bf4--,plan and ,elevation of ,smelting ,plant at ,clichy4 ,the arrangement of the plant at ,clichy is shown diagrammatically in ,fig4 #bf4 ,there is a round shaft furnace1 #j4ed meter in diameter and #d4e meters high4 ,power is supplied to the blower ,c through the pulley ,g and the shaft ,,dd4 ,the compressed air is accumulated in the reservoir ,r1 whence it is conducted by the pipe to the tuyere which is suspended inside of the furnace by means of a chain1 whereby it can be raised or lowered4 ,o and ,o are tap-holes4 ,l is a door and ,n an observation tube4 ,a is the charge tube4 ,x is the pipe which conveys the gas and fume to the condensation chambers4 ,t is the pipe through which the waste gases are drawn4 ,v is the exhauster and ,s is the chimney4 ,k and ,k are tilting crucible furnaces for melting lead and galena4 ,after the furnace has been properly heated1 #ajj kg4 of lead melted in ,k are poured in through the cast-iron pipe ,p1 and after that about #bjj kg4 of pure1 thoroughly melted galena from ,k4 ,ore containing #gj to #hj per cent4 ,pb must be used for this purpose4 ,the blast of air is then introduced into the molten galena1 and from #ajjj to #cjjj kg4 of ore is gradually charged in through the tube ,a4 ,during this operation black fume 7,pb,s7 collects in the condensation chamber4 ,all outlets are closed against the external air4 ,if the air blast is properly adjusted1 nothing but black fume is produced2 if it begins to become light colored1 charging is discontinued and the blast of air is shut off4 ,lead is then tapped through ,o1 which is about #j4b meter above the hearth1 so there is always a bath of lead in the bottom of the furnace2 but it is advisable now and then to tap off some through ,o1 so as gradually to heat up the bottom of the furnace4 ,hearth accretions are also removed through ,o4 ,the lead is tapped off through ,o until matte appears4 ,the tap hole is then closed1 the tuyere is lowered and the blast is turned into the lead in order to oxidize it and completely desulphurize the sulphur combinations1 which is quickly done4 ,the oxide of lead is scorified as a very fusible slag1 which is tapped off through ,o1 and more ore is then charged in upon the lead bath and the cycle of operations is begun again4 ,,part ,,vii ,,dust ,,and ,,fume ,,recovery ,,flues1 ,,chambers ,,and ,,bag-,,houses ,,dust ,,chamber ,,design ,,by ,,max ,j4 ,,welch 7,september #a1 #aijd7 ,only a few years ago smelting companies began to recognize the advantage of large chambers for collecting flue dust and condensing fumes4 ,the object is threefold3 ,first1 profit2 second1 to prevent law suits with surrounding agricultural interests2 third1 cleanliness about the plant4 ,it is my object at present to discuss the materials used in construction and general types of cross-section4 ,most of the old types of chambers are built after one general pattern1 namely1 brick or stone side walls and arch roof1 with iron buckstays and tie rods4 ,the above type is now nearly out of use1 because it is short-lived1 expensive1 and dangerous to repair1 while the steel and masonry are not used to good advantage in strength of cross-section4 ,with the introduction of concrete and expanded metal began a new era of dust-chamber construction4 ,it was found that a skeleton of steel with cement plaster is very strong1 light and cheap4 ,the first flue of the type shown in ,fig4 #bi was built after the design of ,e4 ,h4 ,messiter1 at the ,arkansas ,valley smelter in ,colorado4 ,this flue was in commission several years1 conveying sulphurous gases from the reverberatory roaster plant4 ,the same company decided1 in #aijj1 to enlarge and entirely rebuild its dust-chamber system1 and three types of cross-section were adopted to meet the various conditions4 ,all three types were of cement and steel construction4 ,the first type1 shown in ,fig4 #bg1 is placed directly behind the blast furnaces4 ,the cross-section is #bgc sq4 ft4 area1 being designed for a #aj-;furnace lead smelter4 ,the back part is formed upon the slope of the hillside and paved with #b4e in4 of brick4 ,the front part is of ribbed cast-iron plates4 ,ninety per cent4 of the flue dust is collected in this chamber and is removed1 through sliding doors1 into tram cars4 ,there is a little knack in designing a door to retain flue dust4 ,it is simply to make the bottom sill of the door frame horizontal for a space of about #a in4 outside of the door slide4 ,the front part of the chamber1 ,fig4 #bg1 is of expanded metal and cement4 ,the top is of #bj in4 ,i-beams1 spanning a distance of #bd ft4 with #ae in4 cross-beams and #c in4 of concrete floor resting upon the bottom flanges of the beams4 ,this heavy construction forms the foundation for the charging floor1 bins1 scales1 etc4 ,illustration3 ,,fig4 #bg4--,rectangular form of ,concrete ,dust ,chamber4 ,while dwelling upon this type of construction ,i wish to mention a most important point1 that of the proper factor of safety4 ,flue dust1 collected near the blast furnace1 weighs from #hj to #ajj lb4 per cubic foot1 and the steel supports should be designed for #af1jjj lb4 extreme fiber stress1 when the chamber is three-quarters full of dust4 ,if the dust is allowed to accumulate beyond this point1 the steel1 being well designed1 should not be overstrained4 ,discussions as to strains in bins have been aired by the engineering profession1 but the present question is 8,where is a dust chamber a bin80 ,experience shows that bin construction should be adopted behind1 or in close proximity to1 the blast furnaces4 ,fig4 #bh shows the second type of hopper-bottom flue adopted4 ,it is of very light construction1 of #bgd sq4 ft4 area in the clear4 ,the beginning of this flue being #dgc ft4 from the blast furnaces removes all possibility of any material floor-load1 as the dust is light in weight and does not collect in large quantities4 ,the hopper-bottom floor is formed of #d in4 concrete slabs1 in panels1 placed between #d in4 ,i-beams4 ,cast-iron door frames1 with openings #ab #af in41 are placed on #e ft4 centers4 ,the concrete floor is tamped in place around the frames4 ,the side walls and roof are built of #a in4 angles1 expanded metal1 and plastered to #b4e in4 thickness4 ,at every #aj ft4 distance1 pilaster ribs built of #b in4 angles1 latticed and plastered1 form the wind-bracing and arch roof support4 ,illustration3 ,,fig4 #bh4--;,arched form of ,concrete ,dust ,chamber4 ,fig4 #bi shows the beehive construction4 ,this chamber is of #bec sq4 ft4 cross-sectional area4 ,it is built of #b in4 channels1 placed #af in4 centers1 tied with #a #j4abe in4 steel strips4 ,the object of the strips is to support the #b in4 channels during erection4 ,no4 #bg gage expanded metal lath was wired to the inside of the channels and the whole plastered to a thickness of #c in4 ,the inside coat was plastered first with portland cement and sand1 one to three1 with about #e per cent4 lime4 ,the filling between ribs is one to four1 and the outside coat one to three4 ,the above types of dust chamber have been in use over three years at ,leadville4 ,cement and concrete1 in conjunction with steel1 have been used in ,utah1 ,montana and ,arizona1 in various types of cross-section4 ,the results show clearly where not to use cement2 namely1 where condensing sulphur fumes come in contact with the walls1 or where moisture collects1 forming sulphuric acid4 ,the reason is that portland cement and lime mortar contain calcium hydrate1 which takes up sulphur from the fumes1 forming calcium sulphate4 ,in condensing chambers1 this calcium sulphate takes up water1 forming gypsum1 which expands and peels off4 ,illustration3 ,,fig4 #bi4--;,beehive form of ,concrete ,dust ,chamber4 ,in materials of construction it is rather difficult to get something that will stand the action of sulphur fumes perfectly4 ,the lime mortar joints in the old types of brick flues are soon eaten away4 ,the arches become weak and fall down4 ,i noted a sheet steel condensing system1 where in one year the ,no4 #ab steel was nearly eaten through4 ,with a view of profiting by past experience1 let us consider the acid-proof materials of construction1 namely1 brick1 adobe mortar1 fire-clay1 and acid-proof paint4 ,also1 let us consider at what place in a dust-chamber system are we to take the proper precaution in the use of these materials4 ,at smelting plants1 both copper and lead1 it is found that near the blast furnaces the gases remain hot and dry1 so that concrete1 brick or stone1 or steel1 can safely be used4 ,lead-blast furnace gases will not injure such construction at a distance of #f or #h ft4 away from the furnaces4 ,for copper furnaces1 roasters or pyritic smelting1 concrete or lime mortar construction should be limited to within #bjj or #cjj ft4 of the furnaces4 ,another type of settling chamber is #bj ft4 square in the clear1 with concrete floor between beams and steel hopper bottom4 ,this chamber is built within #aej ft4 distance from the blast furnaces1 and is one of the types used at the ,shannon ,copper ,company's plant at ,clifton1 ,arizona4 ,after passing the #bjj ft4 mark1 there is no need of expensive hopper design4 ,the amount of flue dust settled beyond this point is so small that it is a better investment to provide only small side doors through which the dust can be removed4 ,the ideal arrangement is to have a system of condensing chambers1 so separated by dampers that either set can be thrown out for a short time for cleaning purposes1 and the whole system can be thrown in for best efficiency4 ,as to cross-section for condensing chambers1 ,i consider that the following will come near to meeting the requirements4 ,one1 four1 and six1 concrete foundation2 tile drainage2 #i in4 brick walls1 laid in adobe mortar1 pointed on the outside with lime mortar2 occasional strips of expanded metal flooring laid in joints2 the necessary pilasters to take care of the size of cross-section adopted2 the top covered with unpainted corrugated iron1 over which is tamped a concrete roof1 nearly flat2 concrete to contain corrugated bars in accordance with light floor construction2 and lastly1 the corrugated iron to have two coats of graphite paint on under side4 ,the above type of roof is used under slightly different conditions over the immense dust chamber of the new ,copper ,queen smelter at ,douglas1 ,arizona4 ,the paint is an important consideration4 ,steel work imbedded in concrete should never be painted1 but all steel exposed to fumes should be covered by graphite paint4 ,tests made by the ,united ,states ,graphite ,company show that for stack work the paint1 when exposed to acid gases1 under as high a temperature as #gjj deg4 ,f41 will wear well4 ,,concrete ,,in ,,metallurgical ,,construction#de ,,by ,,henry ,w4 ,,edwards ,the construction of concrete flues of the section shown in ,fig4 #ca gives better results than that shown in ,fig4 #cj1 being less liable to collapse4 ,it costs somewhat more to build owing to the greater complication of the crib1 which1 in both cases1 consists of an interior core only4 ,for work #d in4 in thickness and under1 ,i recommend the use of rock or slag crushed to pass through a #a4e in4 ring4 ,although concrete is not very refractory1 it will easily withstand the heat of the gases from a set of ordinary lead-or copper-smelting blast furnaces1 or from a battery of calcining or roasting furnaces4 ,i have never noticed that it is attacked in any way by sulphur dioxide or other furnace gas4 ,illustration3 ,,figs4 #cj and #ca4--,sections of ,concrete ,flues4 ,shapes the most complicated to suit all tastes in dust chambers can be constructed of concrete4 ,the least suitable design1 so far as the construction itself is concerned1 is a long1 wide1 straight-walled1 empty chamber1 which is apt to collapse1 either inwards or outwards1 and1 although the outward movement can be prevented by a system of light buckstays and tie-rods1 the tendency to collapse inwards is not so simply controlled in the absence of transverse baffle walls4 ,the tendency1 so far as the collection of mechanical flue dust is concerned1 appears to be towards a large empty chamber1 without baffles1 etc41 in which the velocity of the air currents is reduced to a minimum1 and the dust allowed to settle4 ,in the absence of transverse baffle walls to counteract the collapsing tendency1 it seems best to design the chamber with a number of stout concrete columns at suitable intervals along the side and end walls--the walls themselves being made only a few inches thick with woven-wire screen or 8expanded metal0 buried within them4 ,the wire skeleton should also be embedded into the columns in order to prevent the separation of wall and the columns4 ,this method of constructing is one that ,i have followed with very satisfactory results as far as the construction itself is concerned4 ,illustration3 ,,fig4 #cb4--;,concrete ,dust ,chamber at the ,guillermo ,smelting ,works1 ,palomares1 ,spain4 7,horizontal section47 ,figs4 #cb and #cc show a chamber designed and erected at the ,don ,guillermo ,smelting ,works at ,palomares1 ,province of ,murcia1 ,spain4 ,figs4 #cd and #ce show a design for the smelter at ,murray ,mine1 ,sudbury1 ,ontario1 in which the columns are hollow1 thus economizing concrete material4 ,for work of this kind the columns are built first and the wire netting stretched from column to column and partly buried within them4 ,the crib is then built on each side of the netting1 a gang of men working from both sides1 and is built up a yard or so at a time as the work progresses4 ,doors of good size should be provided for entrance into the chamber1 and as they will seldom be opened there is no need for expensive fastenings or hinges4 ,illustration3 ,,fig4 #cc4--;,concrete ,dust ,chamber at the ,guillermo ,smelting ,works1 ,palomares1 ,spain4 7,end elevation47 ,foundations for ,dynamos and other ,electrical ,machinery4--,dry concrete is a poor conductor of electricity1 but when wet it becomes a fairly good conductor4 ,therefore1 if it be necessary to insulate the electrical apparatus1 the concrete should be covered with a layer of asphalt4 ,illustration3 ,,fig4 #cd4--;,concrete ,dust ,chamber designed for smelter at ,murray ,mine1 ,sudbury1 ,ontario1 ,can4 ,there are eight #i ft4 sections in the plan4 ,chimney ,bases4--,fig4 #cf shows the base for the #ij ft4 brick-stack at ,don ,guillermo4 ,the resemblance to masonry is given by nailing strips of wood on the inside of the crib4 ,illustration3 ,,fig4 #ce4--;,concrete ,dust ,chamber designed for smelter at ,murray ,mine1 ,sudbury1 ,ontario1 ,can4 7,end elevation47 ,retaining-,walls4--,figs4 #cg1 #ch1 and #ci show three different styles of retaining-walls1 according to location4 ,these walls are shown in section only1 and show the placing of the iron reenforcements4 ,retaining-walls are best built in panels 7each panel being a day's work71 for the reason that horizontal joints in the concrete are thereby avoided4 ,the alternate panels should be built first and the intermediate spaces filled in afterward4 ,should there be water behind the wall it is best to insert a few small pipes through the wall1 in order to carry it off2 this precaution is particularly important in places where the natural surface of the ground meets the wall1 as shown in ,figs4 #cg and #ch4 ,if a wooden building is to be erected on the retaining-wall1 it is best to bury a few #j4ge in4 bolts vertically in the top of the wall1 by which a wooden coping may be secured 7see ,figs4 #cg1 #ch1 and #ci71 which forms a good commencement for the carpenter work4 ,illustration3 ,,fig4 #cf4--;,concrete ,base for a #ij ft4 ,chimney at the ,guillermo ,smelting ,works1 ,palomares1 ,spain4 ,minimum thickness for a retaining-wall1 having a liberal quantity of iron embedded therein1 is #bj in4 at the bottom and #aj in4 at the top1 with the taper preferably on the inner face4 ,in the absence of interior strengthening irons the thickness of the wall at the bottom should never be less than one-fourth the total hight1 and at the top one-seventh of the hight2 unless very liberal iron bracing be used1 the dimensions can hardly be reduced to less than one-seventh and one-tenth respectively4 ,unbraced retaining-walls are more stable with the batter on the outer face4 ,dry clay is the most treacherous material that can be had behind a retaining-wall1 especially if it be beaten in1 for the reason that it is so prone to absorb moisture and swell1 causing an enormous side thrust against the wall4 ,when this material is to be retained it is best to build the wall superabundantly strong--a precaution which applies even to a dry climate1 because the bursting of a water-pipe may cause the damage4 ,in order to avoid horizontal joints it is best1 wherever practicable1 to build the crib-work in its entirety before starting the concrete4 ,in a retaining-wall #c ft4 thick by #af ft4 high this is not practicable4 ,the supporting posts and struts can1 however1 be completed and the boards laid in as the wall grows1 in order not to interrupt the regular progress of the tamping4 ,a good finish may be produced on the exposed face of the wall by a few strokes of the shovel up and down with its back against the crib4 ,illustration3 ,,figs4 #cg1 #ch1 and #ci4--,retaining-,walls of ,concrete4 ,in conclusion ,i wish to state that this paper is not written for the instruction of the civil engineer1 or for those who have special experience in this line2 but rather for the mining engineer or metallurgist whose training is not very deep in this direction1 and who is so often thrown upon his own resources in the wilderness1 and who might be glad of a few practical suggestions from one who has been in a like predicament4 ,,concrete ,,flues#df ,,by ,,edwin ,h4 ,,messiter 7,september1 #aijd7 ,under the heading 8,flues10 ,mr4 ,edwards refers to the ,beehive construction1 a cross-section of which is shown in ,fig4 #ca of his paper4 ,a flue similar to this was designed by me about six years ago1#dg and in which the walls1 though much thinner than those described by ,mr4 ,edwards1 gave entire satisfaction4 ,these walls1 from #b4be in4 thick throughout in the smaller flues to #c4be in4 in the larger1 were built by plastering the cement mortar on expanded-metal lath1 without the use of any forms or cribs whatever1 at a cost of labor generally less than #a per sq4 yd4 of wall4 ,of course1 where plasterers cannot be obtained on reasonable terms1 the cement can be molded between wooden forms1 though it is difficult to see how it can be done with an interior core only1 as stated by ,mr4 ,edwards4 ,in regard to the effect of sulphur dioxide and furnace gases on the cement1 ,i have found that in certain cases this is a matter which must be given very careful attention4 ,where there is sufficient heat to prevent the existence of condensed moisture inside of the flue1 there is apparently no action whatever on the cement1 but if the concrete is wet1 it is rapidly rotted by these gases4 ,at points near the furnaces there is generally sufficient heat not only to prevent internal condensation of the aqueous vapor always present in the gases1 but also to evaporate water from rain or snow falling on the outside of the flue4 ,further along a point is reached where rain-water will percolate through minute cracks caused by expansion and contraction1 and reach the interior even though internal condensation does not occur there in dry weather4 ,from this point to the end of the flue the roof must be coated on the outside with asphalt paint or other impervious material4 ,in very long flues a point may be reached where moisture will condense on the inside of the walls in cold weather4 ,from this point to the end of the flue it is essential to protect the interior with an acid-resisting paint1 of which two or more coats will be necessary4 ,for the first coat a material containing little or no linseed oil is best1 as ,i am informed that the lime in the cement attacks the oil4 ,for this purpose ,i have used ebonite varnish1 and for the succeeding coats durable metal-coating4 ,the first coat will require about #a gal4 of material for each #ajj sq4 ft4 of surface4 ,in one of the earliest long flues built of cement in this country1 a small part near the chimney was damaged as a result of failure to apply the protective coating1 the necessity for it not having been recognized at the time of its construction4 ,it may be said1 in passing1 that other long brick flues built prior to that time were just as badly attacked at points remote from the furnaces4 ,in order to reduce the amount of flue subject to condensation1 the plastered flues have been built with double lath having an intervening air-space in the middle of the wall4 ,in building thin walls of cement1 such as flue walls1 it is particularly important to prevent them from drying before the cement has combined with all the water it needs4 ,for this reason the work should be sprinkled freely until the cement is fully set4 ,much work of this class has been ruined through ignorance by fires built near the walls in cold weather1 which caused the mortar to shell off in a short time4 ,the great saving in cost of construction1 which the concrete-steel flue makes possible1 will doubtless cause it to supersede other types to even a greater extent than it has already done4 ,if properly designed this type of construction reduces the cost of flues by about one-half4 ,moreover1 the concrete-steel flue is a tight flue as compared with one built of brick4 ,there is a serious leakage through the walls of the brick flues which is not easily observed in flues under suction as most flues are1 but when a brick flue is under pressure from a fan the leakage is surprisingly apparent4 ,in flues operating by chimney-draft the entrance of cold air must cause a considerable loss in the efficiency of the chimney1 a disadvantage which would largely be obviated by the use of the concrete-steel flue4 ,,concrete ,,flues#dh ,,by ,,francis ,t4 ,,havard ,in discussion of ,mr4 ,edwards's interesting and valuable paper1 ,i beg to submit the following notes concerning the advantages and disadvantages of the concrete flues and stacks at the plant of the ,anhaltische ,blei-und ,silber-werke4 ,the flues and smaller stacks at the works were constructed of concrete consisting generally of one part of cement to seven parts of sand and jig-tailings but1 in the case of the under-mentioned metal concrete slabs1 of one part of cement to four parts of sand and tailings4 ,the cost of constructing the concrete flue approximated #e marks per sq4 m4 of area 7equivalent to #j4aa per sq4 ft474 ,effect of ,heat4--,a temperature above #ajj deg4 ,c4 caused the concrete to crack destructively4 ,neutral furnace gases at #abj deg4 ,c41 passing through an independent concrete flue and stack1 caused so much damage by the formation of cracks that1 after two years of use1 the stack1 constructed of pipes #d in4 thick1 required thorough repairing and auxiliary ties for every foot of hight4 ,effect of ,flue ,gases and ,moisture4--,the sides of the main flue1 made of blocks of #f in4 hollow wall-sections1 #ajj cm4 by #ej cm4 in area1 were covered with #b in4 or #a in4 slabs of metal concrete4 ,in cases where the flue was protected on the outside by a wooden or tiled roof1 and inside by an acid-proof paint1 consisting of water-glass and asbestos1 the concrete has not been appreciably affected4 ,in another case1 where the protective cover1 both inside and outside1 was of asphalt only1 the concrete was badly corroded and cracked at the end of three years4 ,in a third case1 in which the concrete was unprotected from both atmospheric influence on the outside1 and furnace gases on the inside1 the flue was quite destroyed at the end of three years4 ,that portion of the protected concrete flue1 near the main stack1 which came in contact only with dry1 cold gases was not affected at all4 ,gases alone1 such as sulphur dioxide1 sulphur trioxide1 and others1 do not affect concrete2 neither is the usual quantity of moisture in furnace gases sufficient to damage concrete2 but should moisture penetrate from the outside of the flue1 and1 meeting gaseous ,,so or ,,so1 form hydrous acids1 then the concrete will be corroded4 ,effect of the ,atmosphere ,alone4--,for outside construction work1 foundations and other structures not exposed to heat1 moist acid gases and chemicals1 the concrete has maintained its reputation for cheapness and durability4 ,effect of ,crystallization of ,contained ,salts4--,in chemical works1 floors constructed of concrete are sometimes unsatisfactory1 for the reason that soluble salts1 noticeably zinc sulphate1 will penetrate into the floor and1 by crystallizing in narrow confines1 cause the concrete to crack and the floor to rise in places4 ,,bag-,,houses ,,for ,,saving ,,fume ,,by ,,walter ,,renton ,,ingalls 7,july #ae1 #aije7 ,one of the most efficient methods of saving fume and very fine dust in metallurgical practice is by filtration through cloth4 ,this idea is by no means a new one1 having been proposed by ,dr4 ,percy1 in his treatise on lead1 page #ddi1 but he makes no mention of any attempt to apply it4 ,its first practical application was found in the manufacture of zinc oxide direct from ores1 initially tried by ,richard and ,samuel ,t4 ,jones in #ahej1 and in #ahea modified by ,samuel ,wetherill into the process which continues in use at the present time in about the same form as originally4 ,in #ahgh a similar process for the manufacture of white lead direct from galena was introduced at ,joplin1 ,mo41 by ,g4 ,t4 ,lewis and ,eyre ,o4 ,bartlett1 the latter of whom had previously been engaged in the manufacture of zinc oxide in the ,east1 from which he obtained his idea of the similar manufacture of white lead4 ,the difference in the character of the ore and other conditions1 however1 made it necessary to introduce numerous modifications before the process became successful4 ,the eventual success of the process led to its application for filtration of the fume from the blast furnaces at the works of the ,globe ,smelting and ,refining ,company1 at ,denver1 ,colo41 and later on for the filtration of the fume from the ,scotch hearths employed for the smelting of galena in the vicinity of ,st4 ,louis4 ,in connection with the smelting of high-grade galena in ,scotch hearths1 the bag-house is now a standard accessory4 ,it has received also considerable application in connection with silver-lead blast-furnace smelting and in the desilverizing refineries4 ,its field of usefulness is limited only by the character of the gas to be filtered1 it being a prerequisite that the gas contain no constituent that will quickly destroy the fabric of which the bags are made4 ,bags are also employed successfully for the collection of dust in cyanide mills1 and other works in which fine crushing is practised1 for example1 in the magnetic separating works of the ,new ,jersey ,zinc ,company1 ,franklin1 ,n4 ,j4 1 where the outlets of the ,edison driers1 through which the ore is passed1 communicate with bag-filtering machines1 in which the bags are caused to revolve for the purpose of mechanical discharge4 ,the filtration of such dust is more troublesome than the filtration of furnace fume1 because the condensation of moisture causes the bags to become soggy4 ,illustration3 ,,fig4 #dj4--;,bag-house1 ,globe ,smelting ,works4 ,the standard bag-house employed in connection with furnace work is a large room1 in which the bags hang vertically1 being suspended from the top4 ,the bags are simply tubes of cotton or woolen 7flannel7 cloth1 from #ah to #bj in4 in diameter1 and #bj to #ce ft4 in length1 most commonly about #cj ft4 ,in the manufacture of zinc oxide1 the fume-laden gas is conducted into the house through sheet-iron pipes1 with suitably arranged branches1 from nipples on which the bags are suspended1 the lower end of the bag being simply tied up until it is necessary to discharge the filtered fume by shaking4 ,in the bag-houses employed in the metallurgy of lead1 the fume is introduced at the bottom into brick chambers1 which are covered with sheet-iron plates1 provided with the necessary nipples2 or else into hopper-bottom1 sheet-iron flues1 with the necessary nipples on top4 ,in either case the bags are tied to the nipples1 and are tied up tight at the top1 where they are suspended4 ,when the fume is dislodged by shaking the bags1 it falls into the chamber or hopper at the bottom1 whence it is periodically removed4 ,the cost of attending a bag-house1 collecting the fume1 etc41 varies from about #aj;c4 per ton of ore smelted in a large plant like the ,globe1 to about #be;c4 per ton in a ,scotch-hearth plant treating #be tons of ore per #bd hours4 ,no definite rules for the proportioning of filtering area to the quantity of ore treated have been formulated4 ,the correct proportion must necessarily vary according to the volume of gaseous products developed in the smelting of a ton of ore1 the percentage of dust and fume contained1 and the frequency with which the bags are shaken4 ,it would appear1 however1 that in blast furnaces and ,scotch-hearth smelting a ratio of #ajjj sq4 ft4 per ton of ore would be sufficient under ordinary conditions4 ,the bag-house originally constructed at the ,globe works had about #bej sq4 ft4 of filtering area per ton of charge smelted1 but this was subsequently increased1 and ,dr4 ,iles1 in his treatise on lead-smelting1 recommends an equipment which would correspond to about #gej sq4 ft4 per ton of charge4 ,at the ,omaha works1 where the ,brown-,de ,camp system was used1 there was #hj1jjj sq4 ft4 of cloth for #aj furnaces #db #abj in41 according to ,hofman's 8,metallurgy of ,lead10 which would give about #ajjj sq4 ft4 per ton of charge smelted1 assuming an average of eight furnaces to be in blast4 ,a bag-house in a ,scotch-hearth smeltery1 at ,st4 ,louis1 had approximately #ijj sq4 ft4 per ton of ore smelted4 ,at the ,lone ,elm works1 at ,joplin1 the ratio was about #cejj sq4 ft4 per ton of ore smelted1 when the works were run at their maximum capacity4 ,in the manufacture of zinc oxide the bag area used to be from #aej to #bjj sq4 ft4 per square foot of grate on which the ore is burned1 but at ,palmerton1 ,pa4 7the most modern plant71 the ratio is only #ajj3a4 ,this corresponds to about #adjj sq4 ft4 of bag area per #bjjj lb4 of charge worked on the grate4 ,in the manufacture of zinc-lead white at ,caon ,city1 ,colo41 the ratio between bag area and grate area is #aej3a4 ,assuming the gas to be free1 or nearly free1 from sulphurous fumes1 the bags are made of unbleached muslin1 varying in weight from #j4d to #j4g oz4 avoirdupois per square foot4 ,the cloth should have #db to #dh threads per linear inch in the warp and the same number in the woof4 ,a kind of cloth commonly used in good practice weighs #j4f oz4 per square foot and has #df threads per linear inch in both the warp and the woof4 ,the bags should be #ah to #bj in4 in diameter4 ,therefore the cloth should be of such width as to make that diameter with only one seam1 allowing for the lap4 ,cloth #fb in4 in width is most convenient4 ,it costs #d to #e;c4 per yard4 ,the seam is made by lapping the edges about #a in41 or by turning over the edges and then lapping1 in the latter case the stitches passing through four thicknesses of the cloth4 ,it should be sewed with ,no4 #ej linen thread1 making two rows of double lock-stitches4 ,the thimbles to which the bags are fastened should be of ,no4 #aj sheet steel1 the rim being formed by turning over a ring of #j4be in4 wire4 ,the bags are tied on with #b in4 strips of muslin4 ,the nipples are conveniently spaced #bg in4 apart1 center to center1 on the main pipe4 ,the gas is best introduced at a temperature of #bej deg4 ,f4 ,too high a temperature is liable to cause them to ignite4 ,they are safe at #cjj deg4 ,f41 but the temperature should not be allowed to exceed that point4 ,the gas is cooled by passage through iron pipes of suitable radiating surface1 but the temperature should be controlled by a dial thermometer close to the bag-house1 which should be observed at least hourly1 and there should be an inlet into the pipe from the outside1 so that1 in event of rise of temperature above #cjj deg41 sufficient cold air may be admitted to reduce it within the safety limit4 ,in the case of gas containing much sulphur dioxide1 and especially any appreciable quantity of the trioxide1 the bags should be of unwashed wool4 ,such gas will soon destroy cotton1 but wool with the natural grease of the sheep still in it is not much affected4 ,the gas from ,scotch hearths and lead-blast furnaces can be successfully filtered1 but the gas from roasting furnaces contains too much sulphur trioxide to be filtered at all1 bags of any kind being rapidly destroyed4 ,,part ,,viii ,,blowers ,,and ,,blowing ,,engines ,,rotary ,,blowers ,,vs4 ,,blowing ,,engines ,,for ,,lead ,,smelting 7,april #bg1 #aija7 ,a note in the communication from ,s4 ,e4 ,bretherton on 8,pyritic ,smelting and ,hot ,blast10 published in the ,engineering and ,mining ,journal of ,april #ac1 #aija1 refers to a subject of great interest to lead smelters4 ,mr4 ,bretherton remarked that he had been recently informed by ,august ,raht that by actual experiment the loss with the ordinary rotary blowers was #ajj per cent4 under #aj lb4 pressure2 that is1 it was possible to shut all the gates so that there was no outlet for the blast to escape from the blower and the pressure was only #aj lb41 or in other words the blower would deliver no air against #aj lb4 pressure4 ,for that reason ,mr4 ,raht expressed himself as being in favor of blowing engines for lead blast furnaces4 ,this is of special interest1 inasmuch as it comes from one who is recognized as standing in the first rank of lead-smelting engineers4 ,mr4 ,raht is not alone in holding the opinion he does4 ,the rotary blower did good service in the old days when the air was blown into the lead blast furnace at comparatively moderate pressure4 ,at the present time1 when the blast pressure employed is commonly #dj oz4 at least1 and sometimes as high as #dh oz41 the deficiencies of the rotary blower have become more apparent4 ,notwithstanding the excellent workmanship which is put into them by their manufacturers1 the extensive surfaces of contact are inherent to the type1 and leakage of air backward is inevitable and important at the pressures now prevailing4 ,the impellers of a rotary blower should not touch each other nor the cylinders in which they revolve1 but they are made with as little clearance as possible1 the surfaces being coated with grease1 which fills the clearance space and forms a packing4 ,this will not1 however1 entirely prevent leakage1 which will naturally increase with the pressure4 ,even the manufacturers of rotary blowers admit the defects of the type1 and concede that for pressures of #e lb4 and upward the cylinder blowing engine is the more economical4 ,metallurgists are coming generally to the opinion1 however1 that blowing engines are probably more economical for pressures of #d lb4 or thereabouts1 and some go even further4 ,with the blowing engines the air-joints of piston and cylinder are those of actual contact1 and the metallurgist may count on his cubic feet of air1 whatever be the pressure4 ,blowing engines were actually introduced several years ago by ,m4 ,w4 ,iles at what is now the ,globe plant of the ,american ,smelting and ,refining ,company1 and we believe their performance has been found satisfactory4 ,the fancied drawback to the use of blowing engines is their greater first cost1 but ,h4 ,a4 ,vezin1 a mechanical engineer whose opinions carry great weight1 pointed out five years ago in the ,transactions of the ,american ,institute of ,mining ,engineers 7,vol4 ,,xxvi7 that per cubic foot of air delivered the blowing engine was probably no more costly than the rotary blower1 but on the contrary cheaper1 stating that the first cost of a cylinder blower is only #bj to #be per cent4 more than that of a rotary blower of the same nominal capacity and the engine to drive it4 ,the capacity of a rotary blower is commonly given as the displacement of the impellers per revolution1 without allowance for slip or leakage backward4 ,mr4 ,vezin expressed the opinion that for the same actual capacity at #b lb4 pressure1 that is1 the delivery in cubic feet against #b lb4 pressure1 the cylinder blower would cost no more than1 if as much as1 the rotary blower4 ,in this connection it is worth while making a note of the increasing tendency of lead smelters to provide much more powerful blowers than were formerly considered necessary1 due1 no doubt1 in large measure to the recognition of the greater loss of air by leakage backward at the pressure now worked against4 ,it is considered1 for example1 that a #db #adj in4 furnace to be driven under #dj oz4 pressure should be provided with a ,no4 #aj blower1 which size displaces #cjj cu4 ft4 of air per revolution and is designed to be run at about #ajj r4p4m42 its nominal capacity is1 therefore1 #cj1jjj cu4 ft4 of air per minute2 although its actual delivery against #dj oz4 pressure is much less1 as pointed out by ,mr4 ,raht and ,mr4 ,bretherton4 ,the ,connersville ,blower ,company1 of ,connersville1 ,ind41 lately supplied the ,aguas ,calientes plant 7now of the ,american ,smelting and ,refining ,company7 with a rotary blower of the above capacity1 and duplicates of it have been installed at other smelting works4 ,the force required to drive such a huge blower is enormous1 being something like #djj h4p41 which makes it advisable to provide each blower with a directly connected compound condensing engine4 ,in view of the favor with which cylindrical blowing engines for driving lead blast furnaces are held by many of the leading lead-smelting engineers1 and the likelihood that they will come more and more into use1 it will be interesting to observe whether the lead smelters will take another step in the tracks of the iron smelters and adopt the circular form of blast furnace that is employed for the reduction of iron ore4 ,the limit of size for rectangular furnaces appears to have been reached in those of #db #ade in41 or approximately those dimensions4 ,a furnace of #ff #afj in41 which was built several years ago at the ,globe plant at ,denver1 proved a failure4 ,h4 ,v4 ,croll at that time advocated the building of a circular furnace instead of the rectangular furnace of those excessive dimensions and considered that the experience with the latter demonstrated their impracticability4 ,in the ,engineering and ,mining ,journal of ,may #bh1 #ahih1 he stated that there was no good reason1 however1 why a furnace of #cjj to #ejj tons daily capacity could not be run successfully1 but considered that the round furnace was the only form permissible4 ,we are unaware whether ,mr4 ,croll was the first to advocate the use of large circular furnaces for lead smelting1 but at all events there are other experienced metallurgists who now agree with him1 and the time is1 perhaps1 not far distant when they may be adopted4 ,,rotary ,,blowers ,,vs4 ,,blowing ,,engines ,,by ,j4 ,,parke ,,channing 7,june #h1 #aija7 ,in the issues of the ,engineering and ,mining ,journal for ,april #acth and #bgth reference was made to the relative efficiency of piston-blowing engines and rotary blowers of the impeller type1 and in these articles ,august ,raht was quoted as saying that1 with an ordinary rotary blower working against #aj lb4 pressure1 the loss was #ajj per cent4 ,i have waited some time with the idea that some of the blower people would call attention to the concealed fallacy in the statement quoted1 but so far have failed to notice any reference to the matter4 ,i feel quite sure that ,mr4 ,bretherton failed to quote ,mr4 ,raht in full4 ,the one factor missing in this statement is the speed at which the blower was run when the loss was #ajj per cent4 ,the accepted method of testing the volumetric efficiency of rotary blowers is that of 8closed discharge40 ,the discharge opening of the blower is closed1 a pressure gage is connected with the closed delivery pipe1 and the blower is gradually speeded up until the gage registers the required pressure4 ,the number of revolutions which the blower makes while holding that pressure1 multiplied by the cubic feet per revolution1 will give the total slip of that particular blower at that particular pressure4 ,experience has shown that1 within the practical limits of speed at which a blower is run1 the slip is a function of the pressure and has nothing to do with the speed4 ,if1 therefore1 it were found that the particular blower referred to by ,mr4 ,raht were obliged to be revolved at the rate of #cj r4p4m4 in order to maintain a constant pressure of #aj lb4 with a closed discharge1 and if the blower were afterward put in practical service1 delivering air1 and were run at a speed of #aej r4p4m41 it would then follow that its delivery of air would amount to3 #aej-cj #abj4 ,its volumetric efficiency would be #abj #aej #hj per cent4 ,the above figures must not be relied upon1 as ,i give them simply by way of illustration4 ,about a year ago ,i had the pleasure of examining the tabulated results of some extensive experiments in this direction1 made by one of the blower companies4 ,i believe they carried their experiments up to #aj lb4 pressure1 and ,i regret that ,i have not the figures before me1 so that ,i could give something definite4 ,i do1 however1 remember that in the experimental blower1 when running at about #aej r4p4m41 the volumetric efficiency at #b lb4 pressure was about #he per cent41 and that at #c lb4 pressure the volumetric efficiency was about #ha per cent4 ,it is unnecessary in this connection to call attention to the horse-power efficiency of rotary blowers4 ,this is a matter entirely by itself1 and there is considerable difference of opinion among engineers as to the relative horse-power efficiency of rotary blowers and piston blowers4 ,all agree that there is a certain pressure at which the efficiency of the blower becomes less than the efficiency of the blowing engine4 ,this ,i have heard placed all the way from #b lb4 up to #f lb4 ,at the smelting plant of the ,tennessee ,copper ,company we have lately installed blast-furnace piston-blowing engines2 the steam cylinders are of the ,corliss type and are #ac and #bd in4 by #db in42 the blowing cylinders are two in number1 each #eg #db in42 the air valves are all ,corliss in type4 ,these blowing engines are designed to operate at a maximum air pressure of #b lb4 per square inch4 ,at the ,santa ,fe ,gold and ,copper ,mining ,company's smelter we have recently installed a ,no4 #h blower directly coupled to a #ad #cb in4 ,corliss engine4 ,this blower has been in use about five months and is giving very good results against the comparatively low pressure of #ab oz41 or lb4 ,during the coming summer it is my intention to make careful volumetric and horse-power tests on these two types of machines under similar conditions of air pressure1 and to publish the results2 but in the meantime ,i wish to correct the error that a rotary blower of the impeller type is not a practicable machine at pressure over #e lb4 ,,blowers ,,and ,,blowing ,,engines ,,for ,,lead ,,and ,,copper ,,smelting ,,by ,,hiram ,w4 ,,hixon 7,july #bj1 #aija7 ,in the ,engineering and ,mining ,journal for ,july #fth ,i note the discussion over the relative merits of blowers and blowing engines for lead and copper smelting1 and wish to state that1 irrespective of the work to be done1 the blast pressure will depend entirely on the charge burden in any kind of blast-furnace work1 and that the charge burden governs the reducing action of the furnace altogether4 ,along these lines the iron industry has raised the charge burden up to #ajj ft4 to secure the full benefit of the reducing action of the carbon monoxide on the ore4 ,in direct opposition to this we have what is known as pyritic smelting1 wherein the charge burden governs the grade of the matte produced to such an extent that if a charge run with #d to #f ft4 of burden above the tuyeres1 producing #dj per cent4 matte1 is changed to a charge burden of #aj or #ab ft41 the grade of the matte will decrease from #dj per cent4 to probably less than #bj per cent4 ,i can state this as a fact from recent experience in operating a blast furnace on heap-roasted ores under the conditions named1 with the result as above stated4 ,i was exceedingly skeptical about pyritic smelting as advocated by some of your correspondents1 and still continue to be so2 but on making inquiries from some of my co-workers in this line1 ,mr4 ,sticht of ,tasmania1 and ,mr4 ,nutting of ,bingham1 ,utah1 ,i have arrived at the following conclusion1 to which some may take exception3 ,that pyritic smelting without fuel1 or with less than #e per cent41 with hot blast1 is practically impossible2 that smelting raw ore with a low charge burden to avoid the reducing action of the carbon monoxide1 thereby securing oxidation of the iron and sulphur1 is possible and practicable1 under favorable conditions2 and that a large portion of the sulphur is burned off1 and the iron1 without reducing action1 goes into the slag in combination with silica4 ,these results can be obtained with cold blast4 ,a blowing engine would certainly be much out of place for operating copper-matting furnaces run with the evident intention of oxidizing sulphur and iron and securing as high a grade of matte as possible1 for the reason that to do this it is necessary to run a low charge burden1 and with a low charge burden a high pressure of blast cannot be maintained4 ,with a #d to #f ft4 charge burden the blast pressure at ,victoria ,mines at present is #c oz41 produced by a ,no4 #f ,green blower run at #abj r4p4m42 and a blowing engine1 delivering the same amount of air1 would certainly not give more pressure4 ,under the conditions which we have1 a fan would be more effective than a pressure blower1 and a blowing engine entirely out of the question as far as economy is concerned4 ,i installed blowing engines at the ,east ,helena for lead smelting where the charge burden was #ba ft4 and the blast pressure at times went up as high as #dh oz4 ,under these conditions the blowing engines gave satisfaction1 but ,i am of the opinion that the same amount of blast could have been obtained under that pressure with less horse-power by the best type of rotary blower4 ,i do not believe that the field of the blowing engine properly exists below #e lb41 and if this pressure cannot be obtained by charge-burden conditions1 their installation is a mistake4 ,i wish to add the very evident fact that varying the grade of the matte by feeding the furnace at different hights varies the slag composition as to its silica and iron contents and makes the feeder the real metallurgist4 ,the reducing action in the furnace is effected almost entirely by the gases1 and when these are allowed to go to waste1 reduction ceases4 ,,blowing ,,engines ,,and ,,rotary ,,blowers--,,hot ,,blast ,,for ,,pyritic ,,smelting ,,by ,s4 ,e4 ,,bretherton 7,august #bd1 #aija7 ,i have just read in the ,engineering and ,mining ,journal of ,july #bjth an interesting letter written by ,hiram ,w4 ,hixon in regard to blowing engines versus the rotary blowers1 and also the use of cold blast for pyritic smelting4 ,the controversy1 which ,i unintentionally started in my letter in the ,engineering and ,mining ,journal of ,april #acth last1 about the advantages of using either blowers or blowing engines for blast furnaces1 does not particularly interest me1 with the exception that ,i have about decided1 in my own mind1 to use blowing engines where there is much back pressure1 and the ordinary up-to-date blower for pyritic or matte smelting where much back pressure should not exist4 ,i fully appreciate the fact that so-called pyritic smelting can be done to a limited extent1 even with cold blast4 ,theoretically1 enough oxygen can be sent into the blast furnace1 contained in the cold blast1 to oxidize both the fuel and the sulphur in an ordinary sulphide charge1 but ,i have not yet learned where a high concentration is being made with unroasted ore and cold blast4 ,i experimented on these lines at different times for three years1 during #ahif1 #ahig1 and #ahih1 making a fair concentration with refractory ores1 most of which had been roasted4 ,i was myself interested in the profits and as anxious as any one for economy4 ,we tried1 for fuel in the blast furnace1 coke alone1 coke and lignite coal1 lignite coal alone1 lignite coal and dry wood1 coal and green wood1 and then coke and green wood1 all under different hights of ore burden in the furnace4 ,a description of these experiments would1 no doubt1 be tiresome to your readers1 but ,i wish to state that the furnace was frozen up several times on account of using too little fuel1 when the cold blast would gradually drive nearly all the heat to the top of the furnace1 the crucible and between the tuyeres becoming so badly crusted that the furnace had to be cleaned out and blown in again1 unless ,i was called in time to save it by changing the charge and increasing the fuel4 ,we were making high-grade matte under contract1 high concentration and small matte fall1 which would1 no doubt1 aggravate matters4 ,after the introduction of hot blast1 heated up to between #bjj and #cjj deg4 ,f41 we made the same grade of matte from the same character of ore1 with the exception that we then smelted without roasting1 and reduced the percentage of fuel consumption1 increased the capacity of the furnace1 and almost entirely obviated the trouble of cold crucibles and hot tops4 ,i write the above facts1 as they speak for themselves4 ,i nearly agree with ,mr4 ,hixon1 and do not think it practical to smelt with much less than #e per cent4 coke continuously2 but there is a great saving between the amount of coke used with a moderately heated blast and cold blast4 ,regardless of either hot or cold blast1 however1 the fuel consumption depends very much on the character of the ore to be smelted1 the amount of matte-fall and grade of matte made4 ,it is not always advisable or necessary to use hot blast for a matting furnace2 that is1 where the supply of sulphur is limited4 ,it may then be necessary to use as much fuel in the blast furnace to prevent the sulphur from oxidizing as will be sufficient to furnish the heat for smelting4 ,such conditions existed at ,silver ,city1 ,n4 ,m4 1 at times1 after our surplus supply of iron and zinc sulphide concentrates was used4 ,i understand that they are now short of sulphur there1 on account of getting a surplus amount of oxidized copper ore1 and are only utilizing what little heat the slag gives them1 without the addition of any fuel on top of the forehearth4 ,before closing this1 which ,i intended to have been brief1 ,i wish to call your attention to a little experience we had with alumina in the matting furnace at ,silverton1 ,col41 where ,i was acting as consulting metallurgist4 ,the ore we had to smelt contained1 on an average1 about #bj per cent4 ,al,o1 #cj per cent4 ,si,o1 with #ah per cent4 ,fe in the form of an iron pyrite1 and no other iron was available except some iron sulphide concentrates containing a small percentage of zinc and lead4 ,the question naturally arose1 could we oxidize and force sufficient of the iron into the slag1 and where should we class the alumina1 as a base or an acid8 ,my experience in lead smelting led me to believe that ,al,o could only be classed as an acid in the ordinary lead furnace1 and that it would be useless to class it otherwise in a shallow matting furnace2 and ,e4 ,w4 ,walter1 the superintendent and metallurgist in charge1 agreed with me4 ,we then decided to make a bisilicate slag1 classing the alumina as silica1 and we obtained fairly satisfactory results4 ,the slag made was very clean1 but treacherous1 which was attributed to two reasons3 ,first1 that it required more heat to keep the alumina slag liquid enough to flow than it does a nearly straight silica slag2 and1 second1 that we were running so close to the formula of a bisilicate and aluminate slag 7about #ca per cent4 ,si,o1 #bg per cent4 ,fe1 #bj per cent4 ,ca,o1 and #ah per cent4 ,al,o1 or #di per cent4 acid7 that a few charges thrown into the furnace containing more silica or alumina than usual would thicken the slag so that it would then require some extra coke and flux to save the furnace4 ,at times the combined ,si,o and ,al,o did reach #ee and #ef per cent4 in the slag1 which did not freeze up the furnace1 but caused us trouble4 ,,part ,,ix ,,lead ,,refining ,,the ,,refining ,,of ,,lead ,,bullion#di ,,by ,f4 ,l4 ,,piddington 7,october #c1 #aijc7 ,in presenting this account of the ,parkes process of desilverizing and refining lead bullion no originality is claimed1 but ,i hope that a description of the process as carried out at the works of the ,smelting ,company of ,australia may be of service4 ,introductory4--,the ,parkes process may be conveniently summarized as follows3 #a4 ,softening of the base bullion to remove copper1 antimony1 etc4 #b4 ,removal of precious metals from the softened bullion by means of zinc4 #c4 ,refining the desilverized lead4 #d4 ,liquation of gold and silver crusts obtained from operation ,no4 #b4 #e4 ,retorting the liquated alloy to drive off zinc4 #f4 ,concentrating and refining bullion from ,no4 #e4 ,softening4--,this is done in reverberatory furnaces4 ,in large works two furnaces are used1 copper1 antimony1 and arsenic being removed in the first and antimony in the second4 ,the size of the furnaces is naturally governed by the quantity to be treated4 ,in these works 7refining about #bjj tons weekly7 a double set of #ae-ton furnaces were at work4 ,the sides and ends of these furnaces are protected by a jacket with a #b-;in4 water space1 the jacket extending some #c in4 above the charge level and #f in4 to #i in4 below it4 ,the furnace is built into a wrought-iron pan1 and if the brickwork is well laid into the pan there need be no fear of lead breaking through below the jacket4 ,the bars of bullion 7containing1 as a rule1 #b to #c per cent4 of impurities7 are placed in the furnace carefully1 to avoid injuring the hearth1 and melted down slowly4 ,the copper dross separates out and floats on top of the charge1 which is stirred frequently to expose fresh surfaces4 ,if the furnace is overheated some dross is melted into the lead again and will not separate out until the charge is cooled back4 ,however carefully the work is done some copper remains with the lead1 and its effects are to be seen in the later stages4 ,the dross is skimmed into a slag pot with a hole bored in it some #d in4 from the bottom2 any lead drained from the pot is returned to the charge4 ,the copper dross is either sent back to the blast furnace direct or may be first liquated4 ,by the latter method some #cj per cent4 of the lead contents of the dross is recovered in the refinery4 ,base bullion made at a customer's smelter will often vary greatly in composition1 and it is1 therefore1 difficult to give any hard and fast figures as to percentage of metals in the dross4 ,as a rule our dross showed #fe to #gj per cent4 lead1 copper #b to #i per cent4 7average #d per cent471 gold and silver values varying with the grade of the original bullion1 though it was difficult to detect any definite relation between bullion and dross4 ,it was1 however1 noticed that gold and silver values increased with the percentage of copper4 ,immediately the copper dross is skimmed off the heat is raised considerably1 and very soon a tin 7and arsenic1 if present7 skimming appears4 ,it is quite 8dry0 and may be removed in an hour or so4 ,it is a very small skimming1 and the tin1 not being worth saving1 is put with the copper dross4 ,the temperature is now raised again and antimony soon shows in black1 boiling1 oily drops1 gathering in time into a sheet covering the surface of the lead4 ,when the skimming is about -inch thick1 slaked lime1 ashes1 or fine coal is thrown on and stirred in4 ,the dross soon thickens up and may be skimmed off easily4 ,this operation is repeated until all antimony is eliminated4 ,constant stirring of the charge is necessary4 ,the addition of litharge greatly facilitates the removal of antimony2 either steam or air may be blown on the surface of the metal to hasten oxidation1 though they have anything but a beneficial effect on the furnace lining4 ,from time to time samples of the dross are taken in a small ladle1 and after setting hard the sample is broken in two4 ,a black vitreous appearance indicates plenty of antimony yet in the charge4 ,later samples will look less black1 until finally a few yellowish streaks are seen1 being the first appearance of litharge4 ,when all antimony is out the fracture of a sample should be quite yellow and the grain of the litharge long1 a short grain indicating impurities still present1 in which case another skimming is necessary4 ,the analysis of a representative sample of antimony dross was as follows3 ,pb,o #gh4aa per cent4 ,sb,o #h4ge 0 0 ,as,o #b4ah 0 0 ,cu,o #j4cf 0 0 ,ca,o #a4aj per cent4 ,fe,o #j4db 0 0 ,al,o #j4hg 0 0 ,insol4 #d4aj 0 0 ,antimony dross is usually kept separate and worked up from time to time1 yielding hard antimonial lead1 used for type metal1 ,britannia metal1 etc4 ,desilverization4--,the softening being completed the charge is tapped and run to a kettle or pan of cast iron or steel1 holding1 when conveniently full1 some #ab or #ac tons4 ,the lead falling into the kettle forms a considerable amount of dross1 which is skimmed off and returned to the softening furnace4 ,by cooling down the charge until it nearly 8freezes0 an additional copper skimming is obtained1 which also is returned to the softener4 ,the kettle is now heated up to the melting point of zinc1 and the zinc charge1 determined by the gold and silver contents of the kettle1 is added and melted4 ,the charge is stirred1 either by hand or steam1 for about an hour1 after which the kettle is allowed to cool down for some three hours and the first zinc crust taken off4 ,when the charge is skimmed clean a sample of the bullion is taken for assay1 and while this is being done the kettle is heated again for the second zinc charge1 which is worked in the same way as the first2 sometimes a third addition of zinc is necessary4 ,the resulting crusts are kept separate1 the second and third being added to the next charge as 8returns10 allowing #c lb4 of zinc in returns as equal to #a lb4 of fresh zinc4 ,an alternative method is to take out gold and silver in separate crusts1 in which case the quantity of zinc first added is calculated on the gold contents of the kettle only4 ,the method of working is the same1 though subsequent treatment may differ in that the gold crusts are cupeled direct4 ,as to the quantity of zinc required3 #a4 ,extracting the gold with as little silver as possible1 the following figures were obtained3 ,total ,gold-- ,au4 ,in kettle #cjj oz4 #a lb4 zinc takes out #a4jj oz4 0 0 #bjj 0 0 0 0 0 #a4jj 0 0 0 #aej 0 0 0 0 0 #j4gi 0 0 0 #ajj 0 0 0 0 0 #j4ei 0 0 0 #fj 0 0 0 0 0 #j4de 0 #b4 ,silver zinking gave the following general results with #aa-ton charges3 ,total ,silver-- ,in kettle #a1dej oz4 #a lb4 zinc takes out #e4f oz4 0 0 #a1bjj 0 0 0 0 0 #d4a 0 0 0 #icj 0 0 0 0 0 #c4h 0 0 0 #gee 0 0 0 0 0 #c4e 0 0 0 #faf 0 0 0 0 0 #c4d 0 0 0 #dfj 0 0 0 0 0 #b4f 0 #c4 ,extracting gold and silver together3 ,,total ,,contents ,,of ,,kettle #a ,,lb4 ,,zinc ,,takes ,,out ,,au4 ,,oz4 ,,ag4 ,,oz4 ,,au4 ,,oz4 ,,ag4 ,,oz4 #did #c1aaj #j4ei #c4fj #ddc #a1hhc #j4fd #b4hj #ccj #b1dag #j4de #c4cd #bjd #a1fch #j4cf #b4hf #adc #a1ccj #j4bh #b4fe #abc #a1cbj #j4bc #b4ed ,it will be noticed that in each case the richer the bullion the greater the extractive power of zinc4 ,experiments made on charges of rich bullion showed that the large amount of zinc called for by the table in use was unnecessary1 and #bej lb4 was fixed on as the first addition of zinc4 ,on this basis an average of #bcg charges gave results as follows3 ,,total ,,contents ,,zinc ,,used #a ,,lb4 ,,zinc ,,takes ,,out ,,au4 ,,oz4 ,,ag4 ,,oz4 ,,lbs4 ,,au4 ,,oz4 ,,ag4 ,,oz4 #ebj #a1ahf #ejg4e #a4bg #b4ia ,the zinc used was that necessary to clean the kettle1 added as follows3 #ast1 #bej lb42 #b;d 7average71 #abg lb42 #c;d 7average71 #eg lb4 ,in #aab cases no third addition was required4 ,from these figures it appears that in the earlier work the zinc was by no means saturated4 ,refining the ,lead4--,gold and silver being removed1 the lead is siphoned off into the refining kettle and the fire made up4 ,in about four hours the lead will be red hot1 and when hot enough to burn zinc1 dry steam1 delivered by a in4 pipe reaching nearly to the bottom of the kettle1 is turned on4 ,the charge is stirred from time to time and wood is fed on the top to assist dezinking and prevent the formation of too much litharge4 ,in three to four hours the lead will be soft and practically free from zinc4 ,when test strips show the lead to be quite soft and clean1 the kettle is cooled down and the scum of lead and zinc oxides skimmed off4 ,in an hour or so the lead will be cool enough for molding2 the bar should have a yellow luster on the face when set2 if the lead is too cold it will be white1 if too hot a deep blue4 ,the refining kettles are subjected to severe strain during the steaming process1 and hence their life is uncertain--an average would be about #fj charges2 the zinking kettles1 on the other hand1 last very much longer4 ,good steel kettles 7if they can be obtained7 are preferable to cast iron4 ,treatment of ,zinc ,crusts4--,having disposed of the lead1 let us return now to the zinc crusts4 ,these are first liquated in a small reverberatory furnace1 the hearth of which is formed of a cast-iron plate 7the edges of the long sides being turned up some #d in47 laid on brasque filling1 with a fall from bridge to flue of in4 per foot and also sloping from sides to center4 ,the operation is conducted at a low temperature and the charge is turned over at intervals1 the liquated lead running out into a small separately fired kettle4 ,this lead rarely contains more than a few ounces of silver per ton2 it is baled into bars1 and returned to the zinking kettles or worked up in a separate charge4 ,in two to three hours the crust is as 8dry0 as it is advisable to make it1 and the liquated alloy is raked out over a slanting perforated plate to break it up and goes to the retort bin4 ,retorting the ,alloy4--,this is carried on in ,faber du ,faur tilting furnaces--simply a cast-iron box swinging on trunnions and lined with firebrick4 ,battersea retorts 7class #dji7 holding #efj lb4 each are used2 their average life is about #cj charges4 ,the retorts are charged hot1 a small shovel of coal being added with the alloy4 ,the condenser is now put in place and luted on2 it is made of in4 iron bent to form a cylinder #ab in4 in diameter1 open at one end2 it is lined with a mixture of lime1 clay and cement4 ,it has three holes1 one on the upper side close to the furnace and through which a rod can be passed into the retort1 a vent-hole on the upper side away from the furnace1 and a tap-hole on the bottom for condensed zinc4 ,in an hour or so the flame from the vent-hole should be green1 showing that distillation has begun4 ,when condensation ceases 7shown by the flame7 the condenser is removed and the bullion skimmed and poured into bars for the cupel4 ,the products of retorting are bullion1 zinc1 zinc powder and dross4 ,bullion goes to the cupel1 zinc is used again in the desilverizing kettles1 powder is sieved to take out scraps of zinc and returned to the blast furnace1 or it may be1 and sometimes is1 used as a precipitating agent in cyanide works2 dross is either sweated down in a cupel with lead and litharge1 together with outside material such as zinc gold slimes from cyanide works1 jeweler's sweep1 mint sweep1 etc41 or in the softening furnace after the antimony has been taken off4 ,in either case the resulting slag goes back to the blast furnace4 ,the total weight of alloy treated is approximately #g per cent4 of the original base bullion4 ,the zinc recovered is about #fj per cent4 of that used in desilverizing4 ,the most important source of temporary loss is the retort dross 7consisting of lead-zinc-copper alloy with carbon1 silica and other impurities71 and it is here that the necessity of removing copper in the softening process is seen1 since any copper comes out with the zinc crusts and goes on to the retorts1 where it enters the dross1 carrying gold and silver with it4 ,if much copper is present the dross may contain more gold and silver than the retort bullion itself4 ,in this connection ,i remember an occasion on which some retort dross yielded gold and silver to the extent of over #hjj and #cjjj oz4 per ton respectively4 ,cupellation4--,retort bullion is first concentrated 7together with bullion resulting from dross treatment7 to #ej to #fj per cent4 gold and silver in a water-jacketed cupel4 ,the side lining is protected by an inch water-pipe imbedded in the lining at the litharge level or by a water-jacket1 the inner face of which is of copper2 the cupel has also a water-jacketed breast so that the front is not cut down4 ,the cupel lining may be composed of limestone1 cement1 fire-clay and magnesite in various proportions1 but a simple lining of sand and cement was found quite satisfactory4 ,when the bullion is concentrated up to #ej to #fj per cent4 gold and silver1 it is baled out and transferred to the finishing cupel1 where it is run up to about #j4iie fine2 it is then ready either for the melting-pot or parting plant4 ,the refining test1 by the way1 is not water-cooled4 ,re-melting is done in #bjj-oz4 plumbago crucibles and presents no special features4 ,in the case of dor bullion low in gold1 8sprouting0 of the silver is guarded against by placing a piece of wood or charcoal on the surface of the metal before pouring1 and any slag is kept back4 ,the quantity of slag formed is1 of course1 very small1 so that the bars do not require much cleaning4 ,the parting plant was not in operation in my time1 and ,i am therefore unable to go into details4 ,the process arranged for was briefly as follows3 ,solution of the dor bullion in ,h,,so2 crystallization of silver as monosulphate by dilution and cooling2 decomposition of silver sulphate by ferrous sulphate solution giving metallic silver and ferric sulphate1 which is reduced to the ferrous salt by contact with scrap iron4 ,the gold and silver are washed thoroughly with hot water and cast into bars4 ,in conclusion1 some variations in practice may be noted4 ,the use of two furnaces in the softening process has already been mentioned2 by this means the drossing and softening are more perfect and subsequent operations thereby facilitated2 further1 the furnaces1 being kept at a more equable temperature1 are less subject to wear and tear4 ,zinc crusts are sometimes skimmed direct into an alloy press in which the excess of lead is squeezed out while still molten2 liquation is then unnecessary4 ,refining of the lead may be effected by a simple scorification in a reverberatory1 the soft lead being run into a kettle from which it is molded into market bars4 ,,the ,,electrolytic ,,refining ,,of ,,base ,,lead ,,bullion ,,by ,,titus ,,ulke 7,october #aa1 #aijb7 ,important changes in lead-refining practice are bound to follow1 in my opinion1 the late demonstration on a large scale of the low working cost and high efficiency of ,betts' electrolytic process of refining lead bullion4 ,it was my good fortune recently to see this highly interesting process in operation at ,trail1 ,british ,columbia1 through the kindness of the inventor1 ,a4 ,g4 ,betts1 and ,messrs4 ,labarthe and ,aldridge1 of the ,trail works4 ,a plant of about #aj tons daily capacity1 which probably cost about #be1jjj1 although it could be duplicated for perhaps #ae1jjj at the present time1 was installed near the ,trail smelting works4 ,it has been in operation for about ten months1 ,i am informed1 with signal success1 and the erection of a larger plant1 of approximately #cj tons capacity and provided with improved handling facilities1 is now completed4 ,the depositing-room contains #bj tanks1 built of wood1 lined with tar1 and approximately of the size of copper-refining tanks4 ,underneath the tank-room floor is a basement permitting inspection of the tank bottoms for possible leakage and removal of the solution and slime4 ,a suction pump is employed in lifting the electrolyte from the receiving tank and circulating the solution4 ,in nearly every respect the arrangement of the plant and its equipment is strikingly like that of a modern copper refinery4 ,the great success of the process is primarily based upon ,betts' discovery of the easy solubility of lead in an acid solution of lead fluosilicate1 which possesses both stability under electrolysis and high conductivity1 and from which exceptionally pure lead may be deposited with impure anodes at a very low cost4 ,with such a solution1 there is no polarization from formation of lead peroxide on the anode1 no evaporation of constituents except water1 and no danger in its handling4 ,it is cheaply obtained by diluting hydrofluoric acid of #ce per cent4 ,,hf1 which is quoted in ,new ,york at #c;c4 per pound1 with an equal volume of water and saturating it with pulverized quartz according to the equation3 ,si,o #f;,,hf ,h,si,f #b;,h,o4 ,according to ,mr4 ,betts1 an acid of #bj to #bb per cent4 will come to about #a per cu4 ft41 or to #a4be when the solution has been standardized with #f lb4 of lead4 ,one per cent4 of lead will neutralize #j4g per cent4 ,h,si,f4 ,the electrolyte employed at the time of my inspection of the works contained1 ,i believe1 #h per cent4 lead and #aa per cent4 excess of fluosilicic acid4 ,the anodes consist of the lead bullion to be refined1 cast into plates about #b in4 thick and approximately of the same size as ordinary two-lugged copper anodes4 ,before being placed in position in the tanks1 they are straightened by hammering over a mold and their lugs squared4 ,no anode sacks are employed as in the old ,keith process4 ,the cathode sheets which receive the regular lead deposits are thin lead plates obtained by electrodeposition upon and stripping from special cathodes of sheet steel4 ,the latter are prepared for use by cleaning1 flashing with copper1 lightly lead-plating in the tanks1 and greasing with a benzine solution of paraffin1 dried on1 from which the deposited lead is easily stripped4 ,the anodes and cathodes are separated by a space of #a to #b in4 in the tank and are electrically connected in multiple1 the tanks being in series circuit4 ,the fall in potential between tanks is only about #j4b of a volt1 which remarkably low voltage is due to the high conducting power of the electrolyte and to some extent to the system of contacts used4 ,these contacts are small wells of mercury in the bus-bars1 large enough to accommodate copper pins soldered to the iron cathodes or clamped to the anodes4 ,only a small amount of mercury is required4 ,current strengths of from #aj to #be amperes per sq4 ft4 have been used1 but at ,trail #ad amperes have given the most satisfactory results as regards economy of working and the physical and chemical properties of the refined metal produced4 ,a current of #a ampere deposits #c4hh grams of lead per hour1 or transports #c times as much lead1 in this case1 as copper with an ordinary copper-refining solution4 ,a little over #ajjj kg41 or #bbdj lb41 requires about #bfj1jjj ampere hours4 ,at #aj amperes per sq4 ft4 the cathode 7or anode7 area should be about #ajhj sq4 ft4 per ton of daily output4 ,taking a layer of electrolyte #a4e in4 thick1 #ace cu4 ft4 will be found to be the amount between the electrodes1 and #age cu4 ft4 may be taken as the total quantity of solution necessary1 according to ,mr4 ,betts' estimate4 ,the inventor states that he has worked continuously and successfully with a drop of potential of only #j4age volt per tank1 and that therefore #j4be volt should be an ample allowance in regular refining4 ,quoting ,mr4 ,betts2 8#bfj1jjj ampere hours at #j4be volt works out to #hg electrical h4p4 hours of #ajj h4p4 hours at the engine shaft1 in round numbers4 ,estimating that #a h4p4 hour requires the burning of #a4e lb4 of coal1 and allowing say #fj lb4 for casting the anodes and refined lead1 each ton of lead refined requires the burning of #baj lb4 of fuel40 ,with coal at #f per ton the total amount of fuel consumed1 therefore1 should not cost over #fj;c41 which is far below the cost of fire-refining base lead bullion1 as we know4 ,in the ,betts electrolytic process1 practically all the impurities in the base bullion remain as a more or less adherent coating on the anode1 and only the zinc1 iron1 cobalt and nickel present go into solution4 ,the anode residue consists practically of all the copper1 antimony1 bismuth1 arsenic1 silver and gold contained in the bullion1 and very nearly #aj per cent4 of its weight in lead4 ,having the analysis of any bullion1 it is easy to calculate with these data the composition of the anode residue and the rate of pollution of the electrolyte4 ,allowing #age cu4 ft4 of electrolyte per ton of daily output1 it will be found that in the course of a year these impurities will have accumulated to the extent of a very few per cent4 ,estimating that the electrolyte will have to be purified once a year1 the amount to be purified daily is less than #a cu4 ft4 for each ton of output4 ,the amount of lead not immediately recovered in pure form is about #j4c per cent41 most of which is finally recovered4 ,as compared with the ordinary fire-refined lead1 the electrolytically refined lead is much purer and contains only mere traces of bismuth1 when bismuthy base bullion is treated4 ,furthermore1 the present loss of silver in fire refining1 amounting1 it is claimed1 to about #a per cent4 of the silver present1 and covered by the ordinary loss in assay1 is to a large extent avoided1 as the silver in the electrolytic process is concentrated in the anode residue with a very small loss1 and the loss of silver in refining the slimes is much less than in treating the zinc crusts and refining the silver residue after distillation4 ,the silver slimes obtained at ,trail1 averaging about #hjjj oz4 of gold and silver per ton1 are now treated at the ,seattle ,smelting and ,refining ,works4 ,there the slimes are boiled with concentrated sulphuric acid and steam1 allowing free access of air1 which removes the greater part of the copper4 ,the washed residue is then dried in pans over steam coils1 and melted down in a magnesia brick-lined reverberatory1 provided with blast tuyeres1 and refined4 ,in this reverberatory furnace the remainder of the copper left in the slimes after boiling is removed by the addition of niter as a flux1 and the antimony with soda4 ,the dor bars finally obtained are parted in the usual way with sulphuric acid1 making silver #j4iii fine and gold bars at least #j4iib fine4 ,mr4 ,betts treated #bjjj grams of bullion1 analyzing #ih4gf per cent4 ,pb1 #j4ej ,ag1 #j4ca ,cu1 and #j4dc ,sb with a current of #be amp4 per square foot in an experimental way1 and obtained products of the following composition3 ,refined ,lead3 #ii4iiga per cent4 ,pb1 #j4jjjc ,ag1 #j4jjjg ,cu1 and #j4jjai ,sb4 ,anode ,residue3 #i4j per cent4 ,pb1 #cf4d ,ag1 #be4a ,cu1 and #b4ie ,sb4 ,four hundred and fifty pounds of bullion from the ,compania ,metalurgica ,mexicana1 analyzing #j4ge per cent4 ,cu1 #a4bb ,bi1 #j4id ,as1 #j4fh ,sb1 and assaying #ceh4i oz4 ,ag and #a4ga oz4 ,au per ton1 were refined with a current of #aj amp4 per square foot1 and gave a refined lead of the following analysis3 #j4jjjbg per cent4 ,cu1 #j4jjcg ,bi1 #j4jjbe ,as1 #j ,sb1 #j4jjaj ,ag1 #j4jjbb ,fe1 #j4jjah ,zn and ,pb 7by difference7 #ii4ihfa per cent4 ,although the present method for recovering the precious metals and by-products from the anode residue leaves much room for improvement1 the use of the ,betts process may be recommended to our lead refiners1 because it is a more economical and efficient method than the fire-refining process now in common use4 ,i will state my belief1 in conclusion1 that the present development of electrolytic lead refining signalizes as great an advance over zinc desilverization and the fire methods of refining lead as electrolytic copper refining does over the old ,welsh method of refining that metal4 ,,electrolytic ,,lead-,,refining#ej ,,by ,,anson ,g4 ,,betts ,a solution of lead fluosilicate1 containing an excess of fluosilicic acid1 has been found to work very satisfactorily as an electrolyte for refining lead4 ,it conducts the current well1 is easily handled and stored1 non-volatile and stable under electrolysis1 may be made to contain a considerable amount of dissolved lead1 and is easily prepared from inexpensive materials4 ,it possesses1 however1 in common with other lead electrolytes1 the defect of yielding a deposit of lead lacking in solidity1 which grows in crystalline branches toward the anodes1 causing short circuits4 ,but if a reducing action 7practically accomplished by the addition of gelatine or glue7 be given to the solution1 a perfectly solid and dense deposit is obtained1 having very nearly the same structure as electrolytically deposited copper1 and a specific gravity of about #aa4cf1 which is that of cast lead4 ,lead fluosilicate may be crystallized in very soluble brilliant crystals1 resembling those of lead nitrate and containing four molecules of water of crystallization1 with the formula ,pb,si,f1#d;,h,o4 ,this salt dissolves at #ae deg4 ,c4 in #bh per cent4 of its weight of water1 making a syrupy solution of #b4ch sp4 gr4 ,heated to #fj deg4 ,c41 it melts in its water of crystallization4 ,a neutral solution of lead fluosilicate is partially decomposed on heating1 with the formation of a basic insoluble salt and free fluosilicic acid1 which keeps the rest of the salt in solution4 ,this decomposition ends when the solution contains perhaps #b per cent4 of free acid2 and the solution may then be evaporated without further decomposition4 ,the solutions desired for refining are not liable to this decomposition1 since they contain much more than #b per cent4 of free acid4 ,the electrical conductivity depends mainly on the acidity of the solution4 ,my first experiments were carried out without the addition of gelatine to the fluosilicate solution4 ,the lead deposit consisted of more or less separate crystals that grew toward the anode1 and1 finally1 caused short circuits4 ,the cathodes1 which were sheet-iron plates1 lead-plated and paraffined1 had to be removed periodically from the tanks and passed through rolls1 to pack down the lead4 ,when gelatine has been added in small quantities1 the density of the lead is greater than can be produced by rolling the crystalline deposit1 unless great pressure is used4 ,the ,canadian ,smelting ,works1 ,trail1 ,b4 ,c4 1 have installed a refinery1 making use of this process4 ,there are #bh refining-tanks1 each #hf in4 long1 #cj in4 wide and #db in4 deep1 and each receiving #bb anodes of lead bullion with an area of #bf by #cc in4 exposed to the electrolyte on each side1 and #bc cathodes of sheet lead1 about #a_/af in4 thick1 prepared by deposition on lead-plated and paraffined iron cathodes4 ,the cathodes are suspended from #j4e by #a in4 copper bars1 resting crosswise on the sides of the tanks4 ,the experiment has been thoroughly tried of using iron sheets to receive a deposit thicker than #a_/af in42 that is1 suitable for direct melting without the necessity of increasing its weight by further deposition as an independent cathode2 but the iron sheets are expensive1 and are slowly pitted by the action of the acid solution2 and the lead deposits thus obtained are much less smooth and pure than those on lead sheets4 ,the smoothness and the purity of the deposited lead are proportional4 ,most of the impurity seems to be introduced mechanically through the attachment of floating particles of slime to irregularities on the cathodes4 ,the effect of roughness is cumulative2 it is often observed that particles of slime attract an undue amount of current1 resulting in the lumps seen in the cathodes4 ,samples taken at the same time showed from #a to #b4e oz4 silver per ton in rough pieces from the iron cathodes1 #j4be oz4 as an average for the lead-sheet cathodes1 and only #j4jd oz4 in samples selected for their smoothness4 ,the variation in the amount of silver 7which is determined frequently7 in the samples of refined lead is attributed not to the greater or less turbidity of the electrolyte at different times1 but to the employment of new men in the refinery1 who require some experience before they remove cathodes without detaching some slime from the neighboring anodes4 ,each tank is capable of yielding1 with a current of #djjj amperes1 #gej lb4 of refined lead per day4 ,the voltage required to pass this current was higher than expected1 as explained below2 and for this reason1 and also because the losses of solution were very heavy until proper apparatus was put in to wash thoroughly the large volume of slime produced 7resulting in a weakened electrolyte71 the current used has probably averaged about #cjjj amperes4 ,the short circuits were also troublesome1 though this difficulty has been greatly reduced by frequent inspection and careful placing of the electrodes4 ,at one time1 the solution in use had the following composition in grams per #ajj c4c43 ,pb1 #f4jg2 ,sb1 #j4jaib2 ,fe1 #j4bdij2 ,si,f1 #f4ic1 and ,as1 a trace4 ,the current passing was #bhjj amperes1 with an average of about #j4dd volts per tank1 including bus-bars and contacts4 ,it is not known what was the loss of efficiency on that date1 due to short circuits2 and it is1 therefore1 impossible to say what resistance this electrolyte constituted4 ,hydrofluoric acid of #ce per cent41 used as a starting material for the preparation of the electrolyte1 is run by gravity through a series of tanks for conversion into lead fluosilicate4 ,in the top tank is a layer of quartz #b ft4 thick1 in passing through which the hydrofluoric acid dissolves silica1 forming fluosilicic acid4 ,white lead 7lead carbonate7 in the required quantity is added in the next tank1 where it dissolves readily and completely with effervescence4 ,all sulphuric acid and any hydrofluoric acid that may not have reacted with silica settle out in combination with lead as lead sulphate and lead fluoride4 ,lead fluosilicate is one of the most soluble of salts2 so there is never any danger of its crystallizing out at any degree of concentration possible under this method4 ,the lead solution is then filtered and run by gravity into the refining-tanks4 ,the solution originally used at ,trail contained about #f per cent4 ,pb and #ae per cent4 ,si,f4 ,the electrical resistance in the tanks was found to be greater than had been calculated for the same solution1 plus an allowance for loss of voltage in the contacts and conductors4 ,this is partly1 at least1 due to the resistance to free motion of the electrolyte1 in the neighborhood of the anode1 offered by a layer of slime which may be anything up to in4 thick4 ,during electrolysis1 the ,si,f ions travel toward the anodes1 and there combine with lead4 ,the lead and hydrogen travel in the opposite direction and out of the slime2 but there are comparatively few lead ions present1 so that the solution in the neighborhood of the anodes must increase in concentration and tend to become neutral4 ,this greater concentration causes an e4m4f4 of polarization to act against the e4m4f4 of the dynamo4 ,this amounted to about #j4jb volt for each tank4 ,the greater effect comes from the greater resistance of the neutral solution with which the slime is saturated4 ,there is1 consequently1 an advantage in working with rather thin anodes1 when the bullion is impure enough to leave slime sticking to the plates4 ,a compensating advantage is found in the increased ease of removing the slime with the anodes1 and wiping it off the scrap in special tanks1 instead of emptying the tanks and cleaning out1 as is done in copper refineries4 ,it is very necessary to have adequate apparatus for washing solution out of the slime4 ,the filter first used consisted of a supported filtering cloth with suction underneath4 ,it was very difficult to get this to do satisfactory work by reason of the large amount of fluosilicate to be washed out with only a limited amount of water4 ,at the present time the slime is first stirred up with the ordinary electrolyte several times1 and allowed to settle1 before starting to wash with water at all4 ,the ,trail plant produces daily #h or #aj cu4 ft4 of anode residue1 of which over #ij per cent4 by volume is solution4 ,the evaporation from the total tank surface of something like #djj sq4 ft4 is only about #ae cu4 ft4 daily2 so that only a limited amount of wash-water is to be used--namely1 enough to replace the evaporated water1 plus the volume of the slime taken out4 ,the tanks are made of #b in4 cedar1 bolted together and thoroughly painted with rubber paint4 ,any leakage is caught underneath on sloping boards4 ,solution is circulated from one tank to another by gravity1 and is pumped from the lowest to the highest by means of a wooden pump4 ,the #bb anodes in each tank together weigh about #c tons1 and dissolve in from #h to #aj days1 two sets of cathodes usually being used with each set of anodes4 ,while #cjj lb4 cathodes can be made1 the short-circuiting gets so troublesome with the spacing used that the loss of capacity is more disadvantageous than the extra work of putting in and taking out more plates4 ,the lead sheets used for cathodes are made by depositing about #a_/af in4 metal on paraffined steel sheets in four of the tanks1 which are different from the others only in being a little deeper4 ,the anodes may contain any or all of the elements1 gold1 silver1 copper1 tin1 antimony1 arsenic1 bismuth1 cadmium1 zinc1 iron1 nickel1 cobalt and sulphur4 ,it would be expected that gold1 silver1 copper1 antimony1 arsenic and bismuth1 being more electronegative than lead1 would remain in the slime in the metallic state1 with1 perhaps1 tin1 while iron1 zinc1 nickel and cobalt would dissolve4 ,it appears that tin stands in the same relation to lead that nickel does to iron1 that is1 they have about the same electromotive forces of solution1 with the consequence that they can behave as one metal and dissolve and deposit together4 ,iron1 contrary to expectation1 dissolves only slightly1 while the slime will carry about #a per cent4 of it4 ,it appears from this that the iron exists in the lead in the form of matte4 ,arsenic1 antimony1 bismuth and copper have electromotive forces of solution more than #j4c volt below that of lead4 ,as there is no chance that any particle of one of these impurities will have an electric potential of #j4c volt above that of the lead with which it is in metallic contact1 there is no chance that they will be dissolved by the action of the current4 ,the same is even more certainly true of silver and gold4 ,the behavior of bismuth is interesting and satisfactory4 ,it is as completely removed by this process of refining as antimony is4 ,no other process of refining lead will remove this objectionable impurity so completely4 ,tin has been found in the refined lead to the extent of #j4jb to #j4jc per cent4 ,this we had no difficulty in removing from the lead by poling before casting4 ,there is always a certain amount of dross formed in melting down the cathodes2 and the lead oxide of this reacts with the tin in the lead at a comparatively low temperature4 ,the extra amount of dross formed in poling is small1 and amounts to less than #a per cent4 of the lead4 ,the dross carries more antimony and arsenic than the lead1 as well as all the tin4 ,the total amount of dross formed is about #d per cent4 ,table ,i shows its composition4 ,the electrolyte takes up no impurities1 except1 possibly1 a small part of the iron and zinc4 ,estimating that the anodes contain #j4ja per cent4 of zinc and soluble iron1 and that there are #aej cu4 ft4 of the solution in the refinery for every ton of lead turned out daily1 in one year the #aej cu4 ft4 will have taken up #ic lb4 of iron and zinc1 or about #a per cent4 ,these impurities can accumulate to a much greater extent than this before their presence will become objectionable4 ,it is possible to purify the electrolyte in several ways4 ,for example1 the lead can be removed by precipitation with sulphuric acid1 and the fluosilicic acid precipitated with salt as sodium fluosilicate4 ,by distillation with sulphuric acid the fluosilicic acid could be recovered1 this process1 theoretically1 requiring but one-third as much sulphuric acid as the decomposition of fluorspar1 in which the fluorine was originally contained4 ,the only danger of lead-poisoning to which the workmen are exposed occurs in melting the lead and casting it4 ,in this respect the electrolytic process presents a distinct sanitary advance4 ,for the treatment of slime1 the only method in general use consists in suspending the slime in a solution capable of dissolving the impurities and supplying1 by a jet of steam and air forced into the solution1 the air necessary for its reaction with1 and solution of1 such an inactive metal as copper4 ,after the impurities have been mostly dissolved1 the slime is filtered off1 dried and melted1 under such fluxes as soda1 to a dor bullion4 ,the amount of power required is calculated thus3 ,five amperes in #bd hours make #a lb4 of lead per tank4 ,one ton of lead equals #aj1jjj ampere-days1 and at #j4ce volts per tank1 #cejj watt-days1 or #d4g electric h4p4 days4 ,allowing #aj per cent4 loss of efficiency in the tanks 7we always get less lead than the current which is passing would indicate71 and of #h per cent4 loss in the generator1 increases this to about #e4f h4p4 days1 and a further allowance for the electric lights and other applications gives from #g to #h h4p4 days as about the amount per ton of lead4 ,at #cj per year1 this item of cost is something like #fe;c4 per ton of lead4 ,so this is an electro-chemical process not especially favored by water-power4 ,the cost of labor is not greater than in the zinc-desilverization process4 ,a comparison between this process and the ,parkes process1 on the assumption that the costs for labor1 interest and general expenses are about equal1 shows that about #a worth of zinc and a considerable amount of coal and coke have been done away with1 at the expense of power1 equal to about #age h4p4 hours1 of the average value of perhaps #fe;c41 and a small amount of coal for melting the lead in the electrolytic method4 ,more important1 however1 is the greater saving of the metal values by reason of increased yields of gold1 silver1 lead1 antimony and bismuth1 and the freedom of the refined lead from bismuth4 ,tables ,,ii1 ,,iii1 and ,,iv show the composition of bullion1 slimes and refined lead4 ,tables ,v1 ,,vi1 ,,vii1 and ,,viii give the results obtained experimentally in the laboratory on lots of a few pounds up to a few hundred pounds4 ,the results in ,tables ,,vi and ,,vii were given me by the companies for which the experiments were made4 ,,table ,i4--,,analyses ,,of ,,dross ,for analyses of the lead from which this dross was taken1 see ,table ,,ii ,,no4 ,,in ,,no4,,table ,,cu4 ,,as4 ,,sb4 ,,fe4 ,,zn4 ,,ii4 ,,per ,,cent4,,per ,,cent4,,per ,,cent4,,per ,,cent4 #a #b #j4jjje #j4jjjc #j4jjaf #j4jjaf none #b #c #j4jjaj #j4jjjh #j4jajg #j4jjaa 8 ,,table ,,ii4--,,analyses ,,of ,,bullion ,,no4 ,,fe4 ,,cu4 ,,sb4 ,,sn4 ,,as4 ,,per ,,cent4,,per ,,cent4,,per ,,cent4,,per ,,cent4,,per ,,cent4 #a #j4jjge #j4agjj #j4edjj #j4jaah #j4adfj #b #j4jaae #j4aejj #j4fajj #j4jaeh #j4jifj #c #j4jjgj #j4afjj #j4djjj #j4jdgd #j4accj #d #j4jafe #j4adjj #j4gjjj #j4jbcf #j4cabj #e #j4jabj #j4adjj #j4hgjj #j4jdcb #j4bbfj #f #j4jjee #j4acjj #j4gcjj #j4jcaf #j4ajcj #g #j4jchj #j4cfjj #j4djcj tr4 ,,no4 ,,ag4 ,,au4 ,,pb4 ,,ag4 ,,au4 ,,per ,,cent4,,per ,,cent4,,per ,,cent4,,oz4 ,p4 ,t4,,oz4 ,p4 ,t4 #a #a4jifb #j4jjhe #ih4jbjj #cai4g #b4di #b #a4bjad #j4jjhf #ig4ijfh #cej4d #b4eb #c #a4jgch #j4jabc #ih4affe #cac4b #c4f #d #j4hiad #j4jaea #ig4ijad #bfj4j #d4db #e #j4fjhb #j4jabd #ih4jhhb #agg4d #c4fc #f #j4ffjj #j4jajf #ih4bfic #aib4e #c4aj #g #j4gbcj #j4jahj #ih4dehj #baj4i #e4be ,,table ,,iii4--,,analyses ,,of ,,slimes ,,fe4 ,,cu4 ,,sb4 ,,sn4 ,,as4 ,,pb4 ,,zn4 ,,bi4 ,,per ,,cent4,,per ,,cent4,,per ,,cent4,,per ,,cent4,,per ,,cent4 #a4bg #h4hc #bg4aj #ab4db #bh4ae #ag4jenonenone #a4ab #bb4cf #ba4af #e4dj #bc4je #aj4fb 8 8 ,,table ,,iv4--,,analyses ,,of ,,refined ,,lead ,,ni1 ,,cu4 ,,as4 ,,sb4 ,,fe4 ,,zn4 ,,sn4 ,,ag4 ,,co1 ,,cd ,,bi4 ,,no4 ,,per ,,per ,,per ,,per ,,per ,,per ,,oz4 ,,per ,,per ,,cent4 ,,cent4 ,,cent4 ,,cent4 ,,cent4 ,,cent4 ,p4 ,t4 ,,cent4,,cent4 #a #j4jjjf #j4jjjh #j4jjje #b #j4jjjc #j4jjjb #j4jjaj #j4jjaj none #c #j4jjji #j4jjja #j4jjji #j4jjjh 0 #j4bd #d #j4jjaf #j4jjag #j4jjad #j4dg none #e #j4jjjc #j4jjfj #j4jjjc #j4bb #f #j4jjbj #j4jjaj #j4jjdf #j4bb none #g #j4jjjd none #j4jjff #j4jjac none #j4jjce #j4ad #h #j4jjjd #j4jjch #j4jjjd 0 #j4jjce #j4be #i #j4jjje #j4jjeb #j4jjjd 0 #j4jjci #j4bh #aj #j4jjjc none #j4jjfj #j4jjjc 0 #j4jjdi #j4dc #aa #j4jjjc 0 #j4jjdb #j4jjac 0 #j4jjei #j4cb #ab #j4jjje 0 #j4jjee #j4jjji 0 #j4jjdi #j4bb #ac #j4jjje 0 #j4jjee #j4jjjg 0 #j4jjia #j4aa #ad #j4jjjd 0 #j4jjfc #j4jjje 0 #j4jjab #j4ad #ae #j4jjjc 0 #j4jjgb #j4jjjc 0 #j4jjbd #j4bd #af #j4jjjf 0 #j4jjfb #j4jjab 0 #j4jjhc #j4bb #ag #j4jjjf 0 #j4jjgb #j4jjaa #j4jjhj #j4bc #ah #j4jjjf 0 #j4jjeg #j4jjaj #j4jjec #j4cd #ai #j4jjje 0 #j4jjff #j4jjaf #j4jadj #j4ch #ai #j4jjje 0 #j4jjdd #j4jjaa #j4jajh #j4ce #bj #j4jjjd 0 #j4jjdg #j4jjae #j4jjgb #j4bb #bj #j4jjjd 0 #j4jjcd #j4jjaf trace #j4bc #ba #j4jjbb 0 #j4jjaj #j4jjdf none #j4jjha #j4ch none none ,,table ,v4--,,analyses ,,of ,,bullion ,,and ,,refined ,,lead ,,ag4 ,,cu4 ,,sb4 ,,pb4 ,,per ,,cent4 ,,per ,,cent4 ,,per ,,cent4 ,,per ,,cent4 ,bullion #j4ej #j4ca #j4dc #ih4gf ,refined lead #j4jjjc #j4jjjg #j4jjai #ii4iiga ,,table ,,vi4--,,analyses ,,of ,,bullion ,,and ,,refined ,,lead ,,cu4 ,,bi4 ,,as4 ,,sb4 ,,ag4 ,,ag4 ,,au4 ,,fe4 ,,zn4 ,,per ,,per ,,per ,,per ,,per ,,per ,,per ,,per ,,per ,,ct4 ,,ct4 ,,ct4 ,,ct4 ,,ct4 ,,ct4 ,,ct4 ,,ct4 ,,ct4 ,bullion #j4ge #a4bb #j4icf #j4fhcbceh4hi #a4ga ,refined lead #j4jjbgj4jjcgj4jjbej4jjjj #j4jjajnone #j4jjbbj4jjah ,,table ,,vii4--,,analyses ,,of ,,bullion1 ,,refined ,,lead ,,and ,,slimes ,,fe1,,zn1 ,,pb4 ,,cu4 ,,as4 ,,sb4 ,,ag4 ,,ag4 ,,ni1,,co4 ,,bi4 ,,per ,,per ,,per ,,per ,,oz4 ,,per ,,per ,,cent4 ,,cent4 ,,cent4 ,,cent4 ,per ,t4 ,,cent4 ,,cent4 about ,bullion #if4gcj4jif #j4he #a4db #bgeea ,refined lead #j4jjacj4jjejf #j4jjbh #j4jjjfhj4jjbgtrace ,slimes 7dry sample7 #i4jea4i #i4ad #bi4ea #icff4i #j4di trace ,,table ,,viii4--,,analyses ,,of ,,bullion1 ,,refined ,,lead ,,and ,,slimes ,,pb4 ,,cu4 ,,bi4 ,,ag4 ,,sb4 ,,as4 ,,per ,,cent4,,per ,,cent4,,per ,,cent4,,per ,,cent4,,per ,,cent4,,per ,,cent4 ,bullion #hg4ad #a4dj #j4ad #j4fd #d4j #g4d ,lead #j4jjaj #j4jjbb #j4jjag trace ,slimes #aj4c #i4c #j4eb #d4g #be4cb #dd4eh ,,part ,x ,,smelting ,,works ,,and ,,refineries ,,the ,,new ,,smelter ,,at ,,el ,,paso1 ,,texas 7,april #ai1 #aijb7 ,in ,july1 #aija1 the ,el ,paso1 ,texas1 plant of the ,consolidated ,kansas ,city ,smelting and ,refining ,company#eb was almost completely destroyed by fire4 ,the power plant1 blast-furnace building and blast furnaces were entirely destroyed1 and portions of the other buildings were badly damaged4 ,the flames were hardly extinguished before steps were taken to construct a new1 modern and enlarged plant on the ruins of the old one1 and on ,april #ae1 #aijb1 nine months after the destruction of the former plant1 the new furnaces were blown in4 ,in rebuilding it was decided to locate the new power-house at some distance from the other buildings4 ,the furnaces have all been enlarged1 each of the new lead furnaces 7of which there are seven7 having about #bjj tons daily capacity4 ,these and the three large copper furnaces have been located in a new position in order to secure a larger building territory4 ,the entire plant is modern and up to date in every particular4 ,one of the interesting features is the substitution of crude oil as fuel in the boiler and roasting departments4 ,it is intended to use ,beaumont petroleum for the generation of power and the roasting of the ores instead of wood1 coal or coke1 and it is expected that a considerable economy will be effected by this means4 ,power ,plant4--,the power plant is complete in all respects4 ,it is a duplicate plant in every sense of the word1 so that it will never be necessary to shut the works down on account of the failure of any one piece of machinery4 ,there are seven boilers1 having a total of #abej h4p4 ,the four blowers are unusually large1 having a capacity of #cj1jjj cu4 ft4 of free air per minute4 ,they are direct-connected to three tandem compound condensing ,corliss engines4 ,no belts are used in this plant1 except for driving a small blower of #aj1jjj cu4 ft4 capacity1 which will act as a regulator4 ,a large central electric plant has been installed in the power-house1 consisting of two direct-connected1 direct-current generators1 mounted on the shafts of two cross-compound condensing ,nordberg-,corliss engines4 ,the current from these generators is transmitted through the plant1 operating sampling works1 briquetting machinery1 pumps1 hoists1 motors1 cars1 etc41 displacing all the small steam engines and steam pumps used in the old plant4 ,the power plant is provided with two systems for condensing2 one being a large ,wheeler surface condenser1 the other a ,worthington central-elevated jet condenser1 the idea being to use the surface condenser during a short period of the year when the water is so bad that it cannot be used in the boilers4 ,during the remainder of the year the jet condenser is in service and the surface condenser can be cleaned4 ,the condensed steam from the surface condenser1 with the necessary additional water1 goes back directly to the boilers when the surface condenser is in use4 ,the power-house is absolutely fireproof throughout1 being of steel and brick with iron and cement floors4 ,it is provided with a traveling crane1 and no expense has been spared to make this1 as all other parts of the plant1 complete in every respect4 ,the main conductors from the generators pass out through a tunnel into a brick and steel lightning-arrester house1 from which point the various distributing lines go to different parts of the plant4 ,blast ,furnaces4--,there are seven large lead furnaces1 each having a capacity of #bjj to #bej tons of charge per day1 and three large copper furnaces1 each having a capacity of #bej to #cjj tons per day4 ,all of the furnaces are enclosed in one steel fireproof building1 the lead furnaces being at one end and the copper furnaces at the other4 ,each of the furnaces has its independent flue system and stack4 ,an entirely new system of feeding these furnaces has been devised1 consisting of a #f ton charge car operated by means of a street railroad motor and controller with third-rail system4 ,the charge cars collect their charge at the ore beds1 lime-rock and coke storage1 and are run on to #ae ton hydraulic elevators4 ,they are then elevated #ch ft4 to the top of the furnaces1 traveling over them to the charging doors1 through which the loads are dumped directly into the furnaces4 ,this system permits of two men handling about #ajjj tons per day4 ,the same system and cars are used for charging the copper furnaces1 except that1 as these furnaces are much lower than the lead furnaces1 the charge is dropped into a large hopper1 from which it is fed to the copper furnaces by a man on the copper furnace feed-floor level4 ,,new ,,plant ,,of ,,the ,,american ,,smelting ,,and ,,refining ,,company ,,at ,,murray1 ,,utah ,,by ,,walter ,,renton ,,ingalls 7,june #bh1 #aijb7 ,murray is a few miles south of ,salt ,lake ,city1 with which it is connected by a trolley line4 ,the new works are situated within a few hundred yards of the terminus of the latter and in close juxtaposition to the old ,germania plant1 which is the only one of the ,salt ,lake lead-smelting works in operation at present4 ,the new plant is of special interest inasmuch as it is the latest construction for silver-lead smelting in the ,united ,states1 and may be considered as embodying the best experience in that industry1 the designers having had access to the results attained at almost all of the previous installations4 ,it will be perceived1 however1 that there has been no radical departure in the methods1 and the novelties are rather in details than in the general scheme4 ,the new works are built on level ground2 there has been no attempt to seek or utilize a sloping or a terraced surface1 save immediately in front of the blast furnaces1 where there is a drop of several feet from the furnace-house floor to the slag-yard level1 affording room for the large matte settling-boxes to stand under the slag spouts4 ,a lower terrace beyond the slag yard furnishes convenient dumping ground4 ,otherwise the elevations required in the works are secured by mechanical lifts1 the ore1 fluxes and coal being brought in almost entirely by means of inclines and trestles4 ,the plant consists essentially of two parts1 the roasting department and the smelting department4 ,the former comprises a crushing mill and two furnace-houses1 one equipped with ,brckner furnaces and the other with hand-raked reverberatories4 ,the reverberatories are of the standard design1 but are noteworthy for the excellence of their construction4 ,similar praise may be1 indeed1 extended to almost all the other parts of the works1 in which obviously no expense has been spared on false grounds of economy4 ,the roasting furnaces stand in a long steel house2 they are set at right angles to the longer axis of the building1 in the usual manner4 ,at their feed end they communicate with a large dust-settling flue1 which leads to the main chimney of the works4 ,the ore is brought in on a tramway over the furnaces and is charged into the furnaces through hoppers4 ,the furnaces have roasting hearths only4 ,the fire-boxes are arranged with step-grates and closed ash-pits1 being fed through hoppers at the end of the furnace4 ,the coal is dumped close at hand from the railway cars1 which are switched in on a trestle parallel with the side of the building1 which side is not closed in4 ,this1 together with a large opening in the roof for the whole length of the building1 affords good light and ventilation4 ,the floor of the house is concrete4 ,the roasted ore is dropped into cars1 which run on a sunken tramway passing under the furnaces4 ,at the end of this tramway there is an incline up which the cars are drawn and afterward dumped into brick bins4 ,from the latter it is spouted into standard-gage railway cars1 by which it is taken to the smelting department4 ,the roasted ore from the ,brckner furnaces is handled in a similar manner4 ,the delivery of the coal and ore to the ,brckners and the general installation of the latter are analogous to the methods employed in connection with the reverberatories4 ,the central feature of the smelting department is the blast-furnace house1 which comprises eight furnaces1 each #dh by #afj in4 at the tuyeres4 ,in their general design they are similar to those at the ,arkansas ,valley works at ,leadville4 ,there are #aj tuyeres per side1 a tuyere passing through the middle of each jacket1 the latter being of cast iron and #af in4 in width2 their length is #f ft41 which is rather extraordinary4 ,the furnaces are very high and are arranged for mechanical charging1 a rectangular brick down-take leading to the dust chamber1 which extends behind the furnace-house4 ,the furnace-house is erected entirely of steel1 the upper floor being iron plates laid on steel ,i-beams1 while the upper terrace of the lower floor is also laid with iron plates4 ,as previously remarked1 the lower floor drops down a step in front of the furnaces1 but there is an extension on each side of every furnace1 which affords the necessary access to the tap-hole4 ,the hight of the latter above the lower terrace leaves room for the large matte settling-boxes1 and the matte tapped from the latter runs into pots on the ground level1 dispensing with the inconvenient pits that are to be seen at some of the older works4 ,the construction of the blast furnaces1 which were built by the ,denver ,engineering ,works ,company1 is admirable in all respects4 ,the eight furnaces stand in a row1 about #cj ft4 apart1 center to center4 ,the main air and water pipes are strung along behind the furnaces4 ,the slag from the matte-settling boxes overflows into single-bowl ,nesmith pots1 which are to be handled by means of small locomotives4 ,the foul slag is returned by means of a continuous pan-conveyor to a brick-lined1 cylindrical steel tank behind the furnace-house1 whence it is drawn off through chutes1 as required for recharging4 ,the charges are made up on the ground level1 immediately behind the furnace-house4 ,the ore and flux are brought in on trestles1 whence the ore is unloaded into beds and the flux into elevated bins4 ,these are all in the open1 there being only two small sheds where the charges are made up and dumped into the cars which go to the furnaces4 ,there are two inclines to the latter4 ,at the top of the inclines the cars are landed on a transferring carriage by which they can be moved to any furnace of the series4 ,the dust-flue extending behind the furnace-house is arranged to discharge into cars on a tramway in the cut below the ground level4 ,this flue1 which is of brick1 connects with the main flues leading to the chimney4 ,the main flues are built of concrete1 laid on a steel frame in the usual manner1 and are very large4 ,for a certain distance they are installed in triplicate2 then they make a turn approximately at right angles and two flues continue to the chimney4 ,at the proper points there are large dampers of steel plate1 pivoted vertically1 for the purpose of cutting out such section of flue as it may be desired to clean4 ,each flue has openings1 ordinarily closed by steel doors1 which give access to the interior4 ,the flues are simple tunnels1 without drift-walls or any other interruption than the arched passages which extend transversely through them at certain places4 ,the chimney is of brick1 circular in section1 #bj ft4 in diameter and #bbe ft4 high4 ,this is the only chimney of the works save those of the boiler-house4 ,the boiler-house is equipped with eight internally fired corrugated fire-box boilers4 ,they are arranged in two rows1 face to face4 ,between the rows there is an overhead coal bin1 from which the coal is drawn directly to the hoppers of the ,american stokers1 with which the boilers are provided4 ,adjoining the boiler-house is the engine-house2 the latter is a brick building1 very commodious1 light and airy4 ,it contains two cross-compound1 horizontal ,allis-,chalmers 7,dickson7 blowing engines for the blast furnaces1 and two direct-connected electrical generating sets for the development of the power required in various parts of the works4 ,a traveling crane1 built by the ,whiting ,foundry ,equipment ,company1 spans the engine-house4 ,in close proximity to the engine-house there is a well-equipped machine shop4 ,other important buildings are the sampling mill and the flue-dust briquetting mill4 ,a noteworthy feature of the new plant is the concrete paving1 laid on a bed of broken slag1 which is used liberally about the ore-yard and in other places where tramming is to be done4 ,the roasting-furnace houses are floored with the same material1 which not only gives an admirably smooth surface1 but also is durable4 ,the whole plant is well laid out with service tramways and standard-gage spur tracks2 the intention has been1 obviously1 to save manual labor as much as possible4 ,,the ,,murray ,,smelter1 ,,utah#ec ,,by ,o4 ,,pufahl 7,may #bf1 #aijf7 ,this plant has been in operation since ,june1 #aijb4 ,it gives employment to #hjj men4 ,the monthly production consists of about #djjj tons of work-lead and #gjj tons of lead-copper matte 7#ab per cent4 lead1 #de per cent4 copper74 ,the work-lead is sent to the refinery at ,omaha2 the matte to ,pueblo1 ,colo4 ,most of the ores come from ,utah2 but in addition some richer lead ores are obtained from ,idaho1 and some gold-bearing ores from ,nevada4 ,for sampling the ,vezin apparatus is used1 cutting out one-fifth in each of three passes1 crushing intervening1 the sample from the third machine being #a_/fbe of the original ore2 after further comminution of sample in a coffee-mill grinder1 it is cut down further by hand1 using a riffle4 ,the final sample is bucked down to pass an #hj-mesh sieve1 but gold ores are put through a #abj-mesh4 ,the steps in the smelting process are as follows3 ,roasting the poorer ores in reverberatory furnaces and in ,brckner cylinders4 ,smelting raw and roasted ores1 mixed1 in water-jacketed blast furnaces1 for work-lead and lead-copper matte1 the latter containing #ae per cent4 lead and #aj to #ab per cent4 copper4 ,roasting the ground matte1 containing #bb per cent4 of sulphur1 down to per cent4 in reverberatory furnaces4 ,smelting the roasted matte together with acid flux in the blast furnace for a matte with #de per cent4 copper and #ab per cent4 lead4 ,only the pyritic ores are roasted in ,brckner furnaces1 the lead ores and matte being roasted in reverberatory furnaces4 ,each of the #bj ,brckner furnaces1 which constitute one battery1 roasts #h to #ab tons of ore in #bd hours down to #e to #f per cent4 sulphur1 with a coal consumption of two tons4 ,the charge weighs #bd tons4 ,the furnaces make one turn in #dj minutes4 ,to increase the draft and the output1 steam at #dj lb4 pressure is blown in through a pipe2 this has1 however1 resulted in increasing the quantity of flue dust to #aj to #ae per cent4 of the ore charged4 ,ten furnaces are attended by one workman with one assistant1 working in eight-hour shifts4 ,for firing and withdrawing the charge five men are required4 ,the gases from the ,brckners and reverberatory furnaces pass into a dust-flue #ad #ad ft4 in section and #fjj ft4 long1 built of brickwork1 with concrete vault2 in the stack 7#bbe ft4 high1 #bj ft4 diameter7 they unite with the shaft-furnace gases1 the temperature of which is only #fj deg4 ,there are #ab reverberatory furnaces with hearths #fj ft4 long and #af ft4 broad4 ,they roast #ad tons of ore 7or #ac tons of matte7 in #bd hours down to #c to #d per cent4 sulphur1 consuming #cb to #cd per cent4 of coal figured on the weight of the charge4 ,there are #ab working doors on each side4 ,the small coal 7from ,rock ,springs1 ,wyoming71 which is burnt on flat grates1 contains #e per cent4 ash and #c to #e per cent4 moisture4 ,the roasted product is dumped through an opening in the hearth1 ordinarily kept closed with an iron plate1 into cars which are raised by electricity on a self-acting inclined plane4 ,their content is then tipped over into a chute and cooled by sprinkling with water4 ,from here the roasted matte is conveyed to the blast furnace in #cj-ton cars4 ,the roasted ore is tipped into the ore-bins4 ,there are eight blast furnaces1 #dh #afj in4 at the tuyeres1 of which there are #aj on each of the long sides4 ,the hight from the tuyeres to the gas outlet is #bj ft41 thence to the throat #f ft42 the distance of the tuyeres from the floor is #d ft4 ,the base is water-cooled4 ,the water-jackets of the furnace are #f ft4 high4 ,the tuyeres 7#d in47 are provided with the ,eilers automatic arrangement for preventing the furnace gases entering the blast pipes4 ,the blast pressure is #cd oz4 ,the furnaces are furnished with the ,arents lead wells2 the crucible holds about #cj tons of lead4 ,the slag and the matte run into a brick-lined forehearth 7#h #c ft41 #d ft4 deep71 from which the slag flows into pots holding #cj cu4 ft41 while the matte is tapped off into flat round pans mounted on wheels4 ,the charge is conveyed to the feed-floor by electricity4 ,the furnace charge is #hjjj lb4 and #ab per cent4 coke1 with #cj per cent1 7figured on the weight of the charge7 of 8shells0 7slag74 ,occasionally as much as #bcj tons of the 7moist7 charge1 exclusive of coke and slag1 has been handled by one furnace in #bd hours4 ,during one month 7,september1 #aijd7 #dj1jjj tons of charge were worked up1 corresponding to a daily average of #aff tons per furnace4 ,the lead in the charge runs from #ac to #ad per cent4 on an average4 ,the limestone1 which is added as flux1 is quarried not far from the works4 ,the coke used is in part a very ordinary quality from ,utah2 in part a better quality from the ,east1 with #i to #aj per cent4 ash4 ,the matte amounts to #aj per cent4 ,the slag contains #j4f to #j4g per cent4 lead and #j4a to #j4ae per cent4 copper4 ,the slag has approximately the following composition3 #cf per cent4 silica1 #bc per cent4 iron 7corresponding to #bi4eg per cent4 ,fe,o71 #bc per cent4 lime1 #c4h per cent4 zinc and #d per cent4 alumina4 ,the work-lead is transferred while liquid from the furnaces to kettles of #cj tons capacity1 in which it is skimmed1 and thence cast in molds through a ,steitz siphon4 ,first1 however1 a #e4e lb4 sample is taken out by means of a special ladle1 and is cast into a plate4 ,from this samples of #j4e a4t4 are punched out at four points for the assay of the precious metals4 ,for the purpose of precipitating the flue dust1 the blast-furnace gases are passed into brickwork chambers in which a plentiful deposition of the heavier particles takes place4 ,from here the gases go through an ,l pipe of sheet iron1 #ah ft4 in diameter1 to the ,monier flues1 which have a cross-section of #bef sq4 ft4 and a total length of #bjjj ft4 ,a small part of the flues is also built of brick4 ,the gases unite with the hot roaster gases just before entering the #bbe ft4 chimney4 ,in the portion of the blast-furnace dust first precipitated the silver runs #bb oz4 per ton1 while that recovered nearer the stack contains only #h oz4 ,the flue dust is briquetted with a small proportion of lime1 and1 after drying1 is returned to the blast furnaces4 ,,the ,,pueblo ,,lead ,,smelters#ed ,,by ,o4 ,,pufahl 7,may #ab1 #aijf7 ,at the ,pueblo plant1 ores containing over #aj per cent4 lead are not roasted1 but are added raw to the charge4 ,for such material as requires roasting there are in use five ,brckner furnaces4 ,the charge is #bd tons for #dh to #fj hours2 the furnaces make one revolution per minute and roast the ore down to #f per cent4 sulphur4 ,there are also two ,o',harra furnaces1 each roasting #be tons daily1 and #aj reverberatory furnaces #ge ft4 in length1 each roasting #ae tons of ore daily down to #d per cent4 sulphur4 ,the charge for smelting is prepared from roasted ore1 together with ,idaho lead ore1 ,cripple ,creek gold ore1 briquetted flue dust1 slag and limestone4 ,there are seven water-jacketed furnaces1 which smelt1 each1 #aej tons of charge per day4 ,the furnaces have #ah tuyeres1 blast pressure #cd oz41 cross-section at the tuyeres #dh #adh in4 ,they are charged mechanically by a car of #d tons' capacity4 ,the output of lead is #aa to #ae tons per furnace4 ,the matte1 which is produced in small quantity1 contains #h to #ab per cent4 lead and the same percentage of copper4 ,it is crushed by rolls1 roasted in reverberatory furnaces1 and smelted with ores rich in silica4 ,the matte resulting at this stage1 running #de to #ej per cent4 in copper1 is shipped to be further worked up for blister copper4 ,the work-lead is purified by remelting in iron kettles1 the cupriferous dross being pressed dry in a ,howard press1 and sent to the blast furnaces4 ,the work-lead is sent to the refineries at ,omaha1 ,neb41 or ,perth ,amboy1 ,n4 ,j4 ,to collect the flue dust the waste gases are passed through long brick flues4 ,the chimneys are #aej to #bjj ft4 high1 and #ae ft4 in diameter4 ,they stand #ge ft4 above the ground level of the blast furnaces4 ,the comparatively small proportion of flue dust produced 7#j4i per cent4 of the charge7 is briquetted1 together with fine ore and #e per cent4 of a thick paste of lime4 ,for this purpose a ,white press is used1 which makes six briquets at a time1 and handles #aj tons per hour4 ,according to a tabulation of the results of five months' running1 the proportion of flue dust at several works of the ,american ,smelting and ,refining ,company is as follows3 ,globe ,plant1 ,denver #j4e of the charge4 ,pueblo ,plant1 ,pueblo #j4i 0 0 0 ,eilers' ,plant1 ,pueblo #j4e 0 0 0 ,east ,helena ,plant1 ,helena #j4c 0 0 0 ,arkansas ,valley ,plant1 ,leadville #j4b 0 0 0 ,murray ,plant1 ,murray1 ,utah #a4b 0 0 0 ,the fuel used is of very moderate quality4 ,the coke 7from beehive ovens7 carries up to #ag per cent4 ash1 the coal #aj to #ah per cent4 ,the monthly production is #bcjj tons of work-lead and #aej tons of copper matte 7#de to #ej per cent4 copper74 ,at the ,eilers plant all sulphide ores1 except the rich ,idaho ore1 are roasted down to #e to #g per cent4 ,s in #ae reverberatory furnaces1 #fj to #gj ft4 in length1 each furnace roasting #ae tons per #bd hours1 in six charges4 ,the flue dust is briquetted together with fine ,cripple ,creek ore1 pyrites cinder from ,argentine1 ,kan41 ,creede ores rich in silica and #aj per cent4 lime4 ,the residue from the zinc smeltery 7,u4 ,s4 ,zinc ,company71 which is brought to this plant 7#fjj tons a month containing nearly #aj per cent4 lead71 is taken direct to the blast furnaces4 ,of the latter there are six1 each with #ah tuyeres1 which handle per #bd hours #afj to #ahj tons of charge1 containing on an average #aj per cent4 of lead in the ore1 with #aj per cent4 of coke1 figured on the charge4 ,the average monthly production of a furnace is about #cfj tons of work-lead1 which is purified at the ,pueblo plant4 ,the furnaces are charged by hand4 ,of the slag1 #cj per cent41 as shells1 etc41 is returned to the charge4 ,the monthly production of work-lead is #bjjj tons1 carrying #aej oz4 of silver and #b to #f oz4 of gold per ton4 ,the matte amounts to about #h4c per cent41 and contains #ab per cent4 copper4 ,it is concentrated up to #de per cent4 ,cu1 which is shipped 7#aej tons a month7 for smelting to blister copper4 ,,the ,,perth ,,amboy ,,plant ,,of ,,the ,,american ,,smelting ,,and ,,refining ,,company#ee ,,by ,o4 ,,pufahl 7,january #bg1 #aijf7 ,these works were erected in #ahie by the ,guggenheim ,smelting ,company4 ,they are situated on ,raritan ,bay1 opposite the southern point of ,staten ,island1 in a position offering excellent facilities for transportation by land and by water4 ,the materials worked up are base lead bullion and crude copper1 containing silver and gold1 chiefly drawn from the company's smelteries in the ,united ,states and ,mexico4 ,silver ore is received from ,south ,america4 ,the ores and base metals from ,mexico and ,south ,america are brought to ,perth ,amboy by the company's steamships 7,american ,smelters ,steamship ,company74 ,ore ,smelting4--,the silver ore from ,south ,america 7containing antimony and much silver1 together with galena1 iron and copper pyrites7 is crushed by rolls and is roasted down from #bf per cent4 to #c per cent4 ,s in #aa reverberatory furnaces1 #gj ft4 long and #ae ft4 wide 7inside dimensions74 ,it is then mixed with rich galena from ,idaho1 pyrites cinder1 litharge1 copper skimmings1 and residues from the desilverizing process1 together with limestone1 and is smelted for work-lead and lead-copper matte in three water-jacketed furnaces1 using #ab per cent4 coke1 figured on the ore in the charge4 ,of these furnaces one has #ab tuyeres2 it measures #db #if in4 in cross-section at the tuyeres1 and #f ft4 #c in4 by #h ft4 at the charging level4 ,the hight of charge is #af ft4 ,the other two furnaces have #af tuyeres each1 their cross-section at the tuyeres being #dd in4 by #abh in41 at the charging level #f ft4 #f in4 by #ab ft41 and hight of charge #af ft4 ,the furnaces are operated at a blast pressure of #ce oz4 per square inch4 ,the temperature of the gases at the throat is #adj deg4 ,f4 7#fj deg4 ,c47 measured with a ,columbia recording thermometer1 which works very well4 ,these furnaces reduce1 respectively1 #ajj to #abj and #acj to #adj tons of charge per #bd hours2 they are also used for concentrating roasted matte4 ,copper ,refining4--,the crude copper is melted in two furnaces of #abe tons aggregate daily capacity1 and is molded into anodes by ,walker casting machines4 ,twenty-six anodes are lifted out of the cooling vessel at a time1 and are taken to the electrolytic plant4 ,the electrolytic plant comprises two systems1 each of #djh vats4 ,the current is furnished by two dynamos1 each giving #dgjj amperes at #aje volts4 ,the cathodes remain in the bath for #ad days4 ,the weight of the residual anodes is #ae per cent4 ,the anode mud is swilled down into reservoirs in the cellar as at ,chrome 7,de ,lamar ,copper ,refining ,company71 is cleaned1 dried and refined in a similar manner4 ,for melting the cathodes there are two reverberatory furnaces of capacity for #ge tons per #bd hours4 ,the wire-bars and ingots are cast with a ,walker machine4 ,about #cbjj tons of refined copper are produced per month4 ,copper ,sulphate ,manufacture4--,the lyes withdrawn from the electrolytic process are worked up into copper sulphate1 shot copper being added4 ,this latter is prepared in a reverberatory furnace from matte obtained as a by-product in working up the lead4 ,about #bjj tons of copper sulphate are thus produced per month2 the process used is the same as at the ,oker works4 ,lower ,harz1 ,germany4 ,the crystals are rinsed1 dried and packed in strong wooden barrels4 ,lead ,refining4--,the working up of the ,mexican raw lead is carried out under the supervision of the customs officers4 ,the lead1 which is imported duty free1 must be exported again4 ,from each bar a sample is cut from above and below by means of a punch entering half way into the bar4 ,for refining the lead there are four reverberatory furnaces of #fj tons capacity1 with hearths #ag ft4 #i in4 by #ab ft4 #f in41 a mean depth of #ad in41 and a grate area of #b ft4 #f in4 by #f ft42 in addition to these there is a furnace of #hj tons capacity with a hearth #ai ft4 #g in4 by #i ft4 #f in41 a mean depth of #ah in41 and grate area of #c ft4 by #f ft4 ,for desilverizing the softened lead there are five kettles1 each of #fj tons capacity1 #aj ft4 #c in4 diameter and #ci in4 depth4 ,the zinc is stirred in with a ,howard mechanical stirrer and the zinc scum is pressed dry in a ,howard press1 which gives a very dry scum4 ,the latter is then1 while still warm1 readily hammered into pieces for the retorts4 ,the desilverized lead is refined in five reverberatory furnaces1 of which four take a charge of #ej tons each1 and one of #fe tons4 ,the production of desilverized lead is #ejjj to #eejj tons a month4 ,the distillation of the zinc crusts is carried out in #ah oil-fired ,faber du ,faur tilting furnaces4 ,each retort receives a charge of #abjj lb4 of broken-up crust and a little charcoal4 ,the distillation lasts #f to #g hours4 ,fifty gallons of petroleum residues are consumed per charge4 ,the oil is blown into the furnace with a compressed air atomizer4 ,after withdrawing the condenser1 which runs on a traveling support1 the argentiferous lead is poured directly from the tilted retort into an ,english cupel furnace4 ,seven such furnaces 7magnesia-lined1 with movable test7 are in use1 of which each works up #d4e to #e tons of retort metal in #bd hours4 ,the furnaces are water-jacketed4 ,the blast is introduced by the aid of a jet of steam4 ,three tons of coal are used per #bd hours4 ,gold and ,silver ,parting4--,the dor bars are cast into anodes for electrolytic parting by the ,moebius process4 ,the plant consists of #add cells in #bd divisions4 ,the mean composition of the electrolytic bath is said to be as follows3 #aj per cent4 free nitric acid1 #ag grams silver1 and #ce to #dj grams copper per liter4 ,the current is furnished by a #fb k4w4 dynamo4 ,one cell consumes #bfj amp4 at #a4ge volts4 ,one k4w4 gives a yield of #afjj oz4 fine silver per #bd hours4 ,the daily production of silver is almost #ajj1jjj oz41 and is exceeded at no other works4 ,about #c1jjj1jjj worth of metal is always on hand in the different departments4 ,,the ,,national ,,plant ,,of ,,the ,,american ,,smelting ,,and ,,refining ,,company#ef ,,by ,o4 ,,pufahl 7,april #ad1 #aijf7 ,this plant1 at ,south ,chicago1 ,ill41 refines base lead bullion4 ,it comprises four reverberatory furnaces1 of which one takes a charge of #ajj tons1 one #hj tons1 and the other two #cj tons each2 one of the small furnaces is being torn down1 and a #abj ton furnace is to be built in its place4 ,the furnaces are fired with coal from ,southern ,illinois1 which contains #aa per cent4 of ash4 ,in softening the bullion1 the time for each charge is #aj hours4 ,the first portion tapped consists of dross rich in copper1 which is followed by antimonial skimmings and litharge4 ,the copper dross is melted up in a small reverberatory furnace1 together with galena from ,wisconsin 7containing #hj per cent4 lead71 for work-lead and lead-copper matte1 the latter containing about #ce per cent4 of copper2 this matte is enriched to #ee per cent4 copper by the addition of roasted matte1 and is finally worked up for crude copper 7#ie per cent47 in a reverberatory furnace4 ,all the copper so produced is used in the parting process for precipitating the silver4 ,the antimonial skimmings are smelted in a reverberatory furnace1 together with coke cinder1 for lead and a slag rich in antimony1 which is reduced to hard lead 7#bg per cent4 antimony1 #j4e per cent4 copper1 #j4e per cent4 arsenic7 in a small blast furnace1 #ad ft4 high1 which has #h tuyeres4 ,the softened lead is tapped off into cast-iron desilverizing pots1 which usually outlive #bjj charges2 in isolated cases as many as #cjj4 ,for desilverizing1 zinc from ,pueblo1 ,colo41 is added in two instalments1 being mixed in by means of a ,howard stirrer4 ,after the first addition there remains in the lead #g oz4 of silver per ton2 after the second only #j4b oz4 ,the first scum is pressed in a ,howard press and distilled2 the second is ladled off and is added to the next charge4 ,the ,howard stirrer is driven by a small steam engine suspended over the kettle2 the ,howard press by compressed air4 ,for distilling zinc scum1 #ab ,faber du ,faur tilting retorts1 heated with petroleum residue1 are used4 ,the argentiferous lead 7with #i4f per cent4 silver7 is transferred from the retort to a pan lined with refractory brick1 which is wheeled to the cupelling hearth and raised by means of compressed-air cylinders1 so as to empty its molten contents through a short gutter upon the cupelling hearth4 ,the cupelling hearths are of the water-cooled ,english type1 and are heated by coal with under-grate blast4 ,the cast-iron test rings1 with reinforcing ribs1 are made in two pieces1 slightly arched and water-cooled2 they are rectangular1 with rounded corners1 and are mounted on wheels4 ,the material of the hearth is marl4 ,argentiferous lead is added as the operation proceeds1 and finally the dor bullion is poured from the tilted test into thick bars 7#aajj oz47 for parting4 ,the desilverized lead is refined in charges of #bh tons 7#d to #e hours7 and #hj to #ij tons 7#h to #aj hours71 introducing steam through four to eight half-inch iron pipes4 ,the first skimmings contain a considerable proportion of antimony and are therefore added to the charge when reducing the antimonial slags in the blast furnace4 ,the litharge is worked up in a reverberatory furnace for lead of second quality4 ,the refined lead is tapped off into a kettle1 from which it is cast into bars through a siphon4 ,the parting of the dor bullion is carried out in tanks of gray cast iron1 in which the solution is effected with sulphuric acid of #fj deg4 ,b4 ,the acid of #dj deg4 ,b4 condensed from the vapors is brought up to strength in leaden pans4 ,in a second larger tank1 which is slightly warmed1 a little gold deposits from the acid solution of sulphates4 ,the solution is then transferred 7by the aid of compressed air7 to the large precipitating tank1 and diluted with water4 ,it is here heated with steam1 and the silver is rapidly precipitated by copper plates 7#abe plates #ah #h #a in47 suspended in the solution from iron hooks covered with hard lead4 ,after the precipitation1 the vitriol lye is siphoned off1 the silver is washed in a vat provided with a false bottom1 is removed with a wooden shovel1 and is pressed into cakes #aj #aj #f in4 ,the refining is finished on a cupelling hearth fired with petroleum residue1 adding saltpeter1 and removing the slag by means of powdered brick4 ,after drawing the last portion of slag the silver 7#j4iii fine7 is kept fused under a layer of wood-charcoal for #bj minutes1 and is then cast into iron molds1 previously blackened with a petroleum flame4 ,the bars weigh about #aajj oz4 ,the gold is boiled with several fresh portions of acid1 is washed and dried1 and finally melted up with a little soda in a graphite crucible4 ,it is #j4iie fine4 ,the lye from the silver precipitation1 after clearing1 is evaporated down to #dj deg4 ,b4 in leaden pans by means of steam coils1 and is transferred to crystallizing vats4 ,the first product is dissolved in water1 the solution is brought up to #dj deg4 ,b4 strength1 and is allowed to crystallize4 ,the purer crystals so obtained are crushed1 and are washed and dried in centrifugal apparatus2 they are then sifted and packed in wooden casks in two grades according to the size of grain4 ,the very fine material goes back into the vats4 ,from the first strongly acid mother liquor1 acid of #fj deg4 ,b4 is prepared by concentrating in leaden pans1 and this is used for the parting operation4 ,,the ,,east ,,helena ,,plant ,,of ,,the ,,american ,,smelting ,,and ,,refining ,,company#eg ,,by ,o4 ,,pufahl 7,april #bh1 #aijf7 ,the monthly production of these works is about #aejj tons of base bullion 7containing #aej oz4 ,ag and #d to #f oz4 ,au per ton71 and #bjj tons of #de per cent4 copper matte4 ,the base bullion is shipped to ,south ,chicago1 the matte to ,pueblo4 ,the ore-roasting is done in two batteries of eight reverberatory furnaces and #af ,brckner furnaces1 the resulting product containing on an average #bj per cent4 lead and #c per cent4 sulphur4 ,the charge for the blast furnaces consists of roasted ore1 rich galena1 argentiferous red hematite1 briquetted flue dust1 slag 7shells7 from the furnace itself1 lead skimmings1 scrap iron and limestone4 ,four tons of the charge are dumped over a roller into a low car1 which is then drawn up an inclined plane to the charging gallery by an electric motor and is then dumped into the furnace4 ,the two rectangular blast furnaces 7,eilers' type7 have eight tuyeres on each of their longer sides and cast-iron water-jackets of #f ft4 hight4 ,the blast is delivered at a pressure of #dj oz4 ,the lead is drawn off through a siphon tap into a cooling kettle4 ,the furnace has a large forehearth for separating the matte and the slag4 ,the slag is received by a two-pot ,nesmith truck1 having an aggregate capacity of #ad cu4 ft4 ,these trucks are hauled to the dump by an electric locomotive4 ,the shells are returned to the furnace with the charge4 ,the matte 7with about #f per cent4 ,cu and the same percentage of lead7 is tapped off into iron molds and after cooling is crushed to #j4be-;in4 size1 to be roasted in the reverberatory furnaces and smelted up together with roasted ore for a #ae per cent4 matte4 ,the latter is crushed1 roasted and separately smelted together with silicious ore for #de per cent4 matte1 which is then sent to ,pueblo to be worked up into blister copper4 ,the small quantity of speiss which is formed is broken up and returned to the blast furnaces with the charge4 ,the slag contains #j4e to #j4h per cent4 lead and #j4e oz4 silver per ton4 ,,the ,,globe ,,plant ,,of ,,the ,,american ,,smelting ,,and ,,refining ,,company#eh ,,by ,o4 ,,pufahl 7,may #e1 #aije7 ,this plant produces #ahjj tons of base bullion per month and #bjj tons of lead-copper matte containing #de to #eb per cent4 of copper4 ,the ores smelted are mostly from ,colorado1 but include also galena from the ,cur d',alene and other supplies4 ,the limestone is quarried #ad miles from ,denver2 coke and coal are brought from ,trinidad1 ,colo4 ,all sulphides1 except the slimes1 concentrates and the rich ,idaho ores1 are roasted4 ,for roasting there are3 7#a7 ,fifteen reverberatory furnaces1 five of which measure #fj #ad ft41 and the other ten #hj #af ft4 externally4 ,in #bd hours these roast six charges of #ddjj lb4 7average7 of moist ore 7#b4ae tons of dry ore7 from #bh to #cj per cent4 down to #c to #d per cent4 sulphur4 ,each furnace is attended by three men working in #ab-;hour shifts2 the stoker earns #b4ge2 the roasters1 #b4cj4 7#b7 ,two ,brown-,o',harra furnaces1 #ij ft4 long1 with two hearths1 and a small sintering furnace attached4 ,they have three grates on each long side1 and each roasts #bf tons of ore in #bd hours down to per cent4 sulphur4 7#c7 ,twelve ,brckner furnaces1 each taking #bd tons' charge1 with under-grate blast1 the air being fed into the cylinders by a steam jet4 ,according to the zinc content of the ores the roasting operation lasts #gj to #ij hours1 the furnace making one revolution per hour4 ,the roasted product from the ,brckner furnaces is pressed into briquets1 together with fine ore1 flue dust and lime4 ,the smelting is carried out in seven blast furnaces1 with #af tuyeres1 blast at #b-lb4 pressure1 hight of furnace #ah ft4 #f in41 section at the tuyeres #db #add in4 ,the charge is #abj to #aej tons exclusive of slag and coke4 ,the slag and the matte are tapped off together into double-bowl ,nesmith cars1 which are hauled1 by an electric locomotive1 to a reverberatory furnace 7hearth #bj #ab ft47 in which they are kept liquid1 for several hours1 in charges of #ad to #ae tons1 in order to effect complete separation4 ,a little work-lead is obtained in this operation1 while the matte is tapped off into cast-iron pans of one ton capacity1 and the slag1 #j4e to #j4f per cent4 lead1 #j4f to #j4g oz4 silver1 is removed in #e-ton pots to the dump4 ,the matte is broken up1 crushed to #j4be in4 size1 roasted in the reverberatory furnaces1 smelted for a #de to #eb per cent4 copper matte1 which is shipped to be further worked up into blister copper4 ,the crude matte contains #aj to #ab per cent4 copper1 #ab to #ae per cent4 lead1 #dj oz4 silver and #j4je oz4 gold4 ,from the siphon taps of the blast furnaces the work-lead is transferred to a cast-iron kettle of #cc tons' capacity4 ,here the copper dross is removed1 the metal is mixed by introducing steam for #aj minutes1 sampled1 and the lead is cast into bars through siphons4 ,it contains about #b per cent4 antimony1 #bjj oz4 silver and #h oz4 gold4 ,this product is refined at ,omaha4 ,the blast-furnace gases pass through a flue #abjj ft4 long1 and enter the bag-house1 in which they are filtered through #djjj cotton bags #cj ft4 long and #ah in4 in diameter4 ,these bags are shaken every #f hours4 ,the material which falls to the floor is burnt where it lies1 sintered and returned to the blast furnaces4 ,in the engine house there are four ,connersville blowers1 two of which are ,no4 #h and two of ,no4 #g size4 ,each blast furnace requires #de1jjj cu4 ft4 of air a minute4 ,the works give employment to #dej men1 whose wages 7for #aj-to #ab-;hour shifts7 are #b to #c4 ,,lead ,,smelting ,,in ,,spain ,,by ,,hjalmar ,,eriksson 7,november #ad1 #aijc7 ,a few notes1 gathered during a couple of years while ,i was employed at one of the large lead works in the southeastern part of ,spain1 are of interest1 not as showing good work1 but for comparing the results obtained in modern practice with those obtained by what is probably the most primitive kind of smelting to be found today4 ,the plant about to be described may serve as a general type for that country4 ,as far as ,i know1 the exceptions are a large plant at ,mazarron1 fully up to date and equipped with the most modern improvements in every line2 a smaller plant at ,almeria1 also in good shape1 and the reverberatory smelting of the carbonates at ,linares4 ,it should be kept in mind1 however1 that the conditions are peculiar1 iron and machinery being very expensive and manual labor very cheap4 ,illustration3 ,,fig4 #da4--,spanish ,lead ,blast ,furnace4 ,about #d ft4 above the tuyeres the furnace is built of uncalcined brick made of a black graphitic clay found in the mines near by2 the upper part is of common red brick4 ,the entire cost of one furnace does not reach #ajj4 ,the flue leads to a main gallery #c4e by #g ft41 which goes down to the ground1 and extends several times around a hill1 the chimney being placed on the top of the hill1 considerably above the furnace level4 ,the gallery is about #aj1jjj ft4 long1 and is laid down in the earth1 with the arched roof just emerging4 ,it is all built of rough stone1 the inside being plastered with gypsum4 ,the furnace has three tuyeres of #c in4 diameter4 ,the blast pressure is generally #d to #f in4 of water4 ,neither feeding floor nor elevators are used1 only a couple of scaffolds1 the charge being lifted up gradually by hand in small convenient buckets made of sea-grass4 ,when charging the furnace1 coke is piled up in the center1 and the mixture of ore1 fluxes and slag is charged around the walls4 ,the slag and matte are left to run out together on an inclined sand-bed4 ,the matte1 flowing more quickly1 goes further and leaves the slag behind1 but the separation thus obtained is1 of course1 very unsatisfactory4 ,the charge mixture is weighed and made for each furnace every morning4 ,when it is all put through1 the furnace is run down very low1 without any protecting cover on the top2 several iron bars are driven through the furnace at the slag-tap level1 for holding up the charge2 the lead is all tapped out2 a big hole is made in the crucible for the purpose of cleaning it out2 all accretions are loosened with a bar2 the hole is closed with mud of the graphitic clay2 bars are removed1 when the crucible is filled with coke from the center and the charging is continued4 ,in this way a furnace can be kept running for any length of time1 but at a great loss of heat1 and with a great increase of flue dust4 ,the current practice1 in many parts of ,spain1 is to run the same number of ore-smelting and of matte-smelting furnaces4 ,all the slag and the raw matte1 produced by the ore-smelting furnaces1 is re-smelted in the matte furnaces1 together with some dry silver ores4 ,no lead at all is produced in the matte furnaces1 only a matte containing up to #aej oz4 silver per ton and #be to #ce per cent4 of the lead charged on them4 ,this rich matte is calcined in kilns1 and smelted together with the ore charge4 ,the ores we smelted were galena ranging from #e to #hc per cent4 lead and about #bej oz4 silver per ton of lead2 dry silver ores containing up to #abj oz4 silver per ton1 and enough of the ,linares carbonates for keeping the silver below #abj oz4 per ton in the lead4 ,the gangue of the galena was mainly iron carbonate4 ,most of that ore was hand picked and of nut size4 ,machine concentrates with more than #cj per cent4 lead or containing much pyrite were calcined2 everything else was smelted raw4 ,the flux exclusively used1 before ,i came1 was carbonate of iron1 which1 by the way1 was considered a 8cure-for-all40 ,the slag analyses showed3 ,ca,o1 below #d per cent4 ,fe,o1 above #de per cent4 ,si,o1 about #cj per cent4 ,ba,o1 #e to #aj per cent4 ,al,o1 #e to #aj per cent4 ,pb1 by fire assay1 #j4ge to #b4e per cent4 ,ag1 by fire assay1 #b to #c oz4 per ton4 ,the specific gravity of the slag was about #e1 or practically the same as that of the matte4 ,the output of metallic lead was about #gj per cent42 of silver1 #hd per cent4 ,the working hight of the furnaces--tuyere level to top of charge--was at that time only #g ft41 and ,i was told that it had been still lower before4 ,to the working hight of the furnaces was added #b ft41 simply by putting up the charging doors that much4 ,a very good limestone was found just outside the fence around the plant4 ,enough limestone was substituted for the iron carbonate1 to keep the lime up to #ab per cent4 in the slag1 reducing the ,fe,o to below #ce per cent4 and the specific gravity to below four4 ,the result of these alterations was an increase in the output of metallic lead1 from #gf to #he per cent42 of silver from #hd to #ij per cent42 a comparatively good separation of slag and matte1 and a slag running about #j4e to #j4ge per cent4 ,pb and #a4e oz4 ,ag per ton4 ,owing to the great extent of the gallery1 and the consequent good condensation of the flue dust1 the total loss of lead and silver was much smaller than would be expected2 in no case being found above #d per cent4 ,the composition of the charge was #ee per cent4 ore and roasted matte1 #ac per cent4 fluxes1 and #cb per cent4 slag4 ,coke used was #aa per cent4 on charge1 or #bj per cent4 on ore smelted4 ,each furnace put through #aj to #ae tons of charge1 or #g tons of ore1 in #bd hours4 ,eight men and two boys were required for each furnace1 including slag handling and making up of the charge4 ,the cost of smelting was #ag pesetas per ton of ore1 which at the usual premium 7#a #cd pesetas #d4he7 equals #b4dc4 ,this cost is divided as follows3 ,coke #a4dg ,fluxes #j4jd ,labor #j4fe ,coal for power #j4aj ,general expenses #j4ag --------- ,total #b4dc ,this #b4dc per ton includes all expenses of whatever kind4 ,the iron carbonate flux contained lead and silver1 which was not paid for4 ,the fluxes are credited for the actual value of this lead and silver4 ,without making this discount1 the cost of flux would amount to #bf;c4 per ton1 making the entire smelting cost come to #b4fe4 ,as an explanation of the low cost of labor1 it may be noted that the wages were1 for the furnace-man1 #b4be pesetas1 or #cb;c4 a day2 for the helpers1 #a4ge pesetas1 or #be;c4 a day4 ,the basis for purchasing the galena ore may here be given1 reduced to ,american money2 lead and silver are paid for according to the latest quotations for refined metals given by the ,revista ,minera1 published at ,cartagena4 7,the quotations are the actual value in ,cartagena of the ,london quotations47 ,the following discounts are made3 #e per cent4 for both silver and lead2 #f4dj per ton on ore containing #g per cent4 ,pb and below2 this rises gradually to a discount of #g4ge per ton of ore containing #cj per cent4 ,pb and above4 ,the transportation is paid by the purchaser and amounts to about #a4bj per ton of ore4 ,the dry silver ores were cheaper than this and the lead carbonates much more expensive4 ,,lead ,,smelting ,,at ,,monteponi1 ,,sardinia#ei ,,by ,,erminio ,,ferraris 7,october #bh1 #aije7 ,in dressing mixed lead and zinc carbonate ores by the old method of gradual crushing with rolls1 middling products were obtained1 which could be further separated only with much loss4 ,inasmuch as the losses in the metallurgical treatment of such mixed ore were reckoned to be less than in ore dressing1 these between-products at ,monteponi were saved for a number of years1 until there should be enough raw material to warrant the erection of a small lead and zinc smeltery4 ,in #ahid the lead smeltery in ,monteponi was put in operation2 in #ahii the zinc smeltery was started4 ,at about the same time the reserves of lead ore were exhausted1 and the lead plant then began to treat all the ,monteponi ores and a part of those from neighboring mines4 ,as will be seen from the plan 7,fig4 #db71 the smelting works cluster in terraces around the mine shaft1 covering an area of about #cjjj sq4 m4 7#j4ge acre72 the ore stocks and the pottery of the zinc works are located in separate buildings4 ,during the first years of working1 the slag had purposely been kept very rich in zinc1 in the hope of utilizing it later for the production of zinc oxide4 ,it had an average zinc content of #af4hj per cent41 or #ba per cent4 of zinc oxide1 with about #cb per cent4 ,si,o1 #be per cent4 ,fe,o1 and #ad per cent4 lime4 ,according to the recent experiments1 this slag can very well be used for oxide manufacture1 in connection with calamine rich in iron4 ,the slag made at the present time has only #ae per cent4 ,zn,o2 #be per cent4 ,si,o2 #af per cent4 ,ca,o2 #c per cent4 ,mg,o2 #cc per cent4 ,fe,o2 #b4e per cent4 ,al,o1 and #b per cent4 ,ba,o1 and small quantities of alkalies1 sulphur and lead 7#a to #a4e per cent74 ,the following classes of ore are produced at ,monteponi3 #a4 ,lead carbonates1 with a little zinc oxide2 these ores are screened down to #aj mm4 ,the portion held back by the screen is sent straight to the shaft furnaces2 the portion passing through is either roasted together with lead sulphides1 or is sintered by itself1 according to circumstances4 #b4 ,dry lead ores1 mostly quartz1 with #aj to #ae per cent4 lead1 which are mixed for smelting with the lead carbonates4 ,illustration3 ,,fig4 #db4--;,general ,plan of ,works4 #c4 ,lead sulphides1 which are crushed fine and roasted dead4 ,quartz sand is added in the roasting1 in order to decompose the lead sulphate and produce a readily fusible silicate2 as quartz flux1 fine sand from the dunes on the coast is used4 ,this is a product of decomposition of trachyte1 and contains #hh per cent4 of silica1 together with alkalies and alumina4 ,the roast is effected in two hand-raked reverberatory furnaces1 #ah m4 long1 which turn out #ab1jjj kg4 of roasted ore in #bd hours1 consuming #ahjj kg4 of ,english cannel coal1 or #bdjj kg4 of ,sardinian lignite4 ,there is also a third reverberatory furnace1 provided with a fusion chamber1 which is used for roasting matte and for liquating various secondary products4 ,the charge for the shaft furnace1 as a rule1 consists of #ej per cent4 ore 7crude and roasted71 #bj per cent4 fluxes and #cj per cent4 slag of suitable origin4 ,the fluxes used are limestone from the mine1 containing #ih per cent4 ,ca,c,o1 and limonite from the calamine deposits4 ,this iron ore contains #dh per cent4 ,fe1 not more than #d per cent4 ,zn1 a little lead and traces of copper and silver4 ,a shaft furnace will work up a charge of #fj tons1 equal to #cj tons of ore1 in #bd hours1 with a coke consumption of #ab per cent4 of the weight of the charge and a blast pressure of #ej mm4 of mercury4 ,there are three furnaces1 of which two are used alternately for smelting lead ores1 while one smaller furnace serves for smelting down products1 such as hard lead1 copper matte and copper bottoms4 ,illustration3 ,,fig4 #dc4--;,elevation of works on line ,a ,b ,c ,d ,e ,f of ,fig4 #db4 ,figs4 #dc to #df show one of the furnaces4 ,it will be seen at once that its construction is similar to that of the standard ,american furnaces4 ,pilz furnaces were tried in the first few years1 but were finally abandoned1 as they could not be kept running for any satisfactory length of time with slags rich in zinc4 ,diluting the slag1 on the other hand1 would have led to an increased coke consumption1 and would have rendered the slag itself worthless4 ,the furnace1 however1 differs in several respects from its ,american prototype2 the following are some of the chief characteristics peculiar to it3 ,illustration3 ,section ,e ,f4 ,section ,g ,h4 ,,fig4 #dd4--,shaft ,furnace for ,lead ,smelting4 ,the chimney above the feed-floor covers one-third of the furnace shaft1 and is turned down in the form of a siphon1 to connect with the flue-dust chamber4 ,the lateral faces1 which are left open1 serve as charging apertures2 the central one of these1 provided with a counterbalanced sheet-iron door1 is used for charging from cars4 ,the square openings at the ends1 which are covered with cast-iron plates1 are used for barring down the furnace shaft and may also be used for charging4 ,by this arrangement1 together with the two hoppers placed laterally on the chimney1 it is possible to distribute the charge in any desired manner over the whole cross-section of the furnace4 ,this arrangement greatly facilitates the removal of any accretions in the furnace shaft1 as the centrally placed chimney catches all the smoke1 while the charge-holes render the furnace accessible on all sides4 ,in case of large accretions being formed1 the whole furnace can be emptied1 cleaned and restarted in #bd to #cf hours4 ,the smelting cone is enclosed by cast-steel plates #ej cm4 high1 instead of having a water-jacket4 ,these are cooled as desired by turning a jet of water on them4 ,the plates are connected to the furnace shaft by a bosh wall #be cm4 thick1 which is surrounded with a boiler-plate jacket4 ,these jacket plates also are cooled from the outside by sprays of water4 ,with this arrangement the consumption of water is less than with water-jackets1 as a part of the water is vaporized1 and the danger of leakage of the jackets is avoided4 ,the cast-steel plates are made in two patterns2 there are two similar side-plates1 each with four slits for the tuyeres1 and two end-plates1 provided with a circular breast of #cj cm4 aperture1 for tapping the slag4 ,the breast is cooled by water flowing down1 and is closed in front by a plate of sheet iron1 in which is the tap-hole for running off the slag4 ,when cleaning out1 this sheet-iron plate is removed and the breast is opened1 thus providing easy access to the hearth4 ,the four cast-steel plates are anchored together with bolts at their outer ribs1 and rest on two long1 gutter-shaped pieces of sheet iron1 which carry off all the water which flows down1 and keep it away from the brickwork of the hearth4 ,illustration3 ,section ,j ,l4 ,section ,c ,d4 ,,fig4 #de4--,shaft ,furnace4 ,the hearth1 cased with boiler plate and rails1 has at the side a cast-iron pipe of #aj cm4 diameter for drawing off the lead to the outside kettle2 this pipe has a slight downward inclination1 to prevent the slag flowing out2 every #bj minutes lead is tapped1 and the end of the pipe is then plugged up with clay4 ,the furnace shaft is supported upon a hollow mantel1 which serves at the same time as blast-pipe4 ,the blast-pipe has eight lateral tees1 which are connected by canvas hose with the eight tuyeres4 ,the mouth of the tuyeres has the form of a horizontal slit1 whereby the air is distributed more evenly over the entire zone of fusion4 ,illustration3 ,,fig4 #df4--,shaft ,furnace for ,lead ,smelting4 7,section ,a ,b47 ,the precipitation of flue dust is effected in a brick condensing chamber1 placed near the beginning of the main flue4 ,the main flue terminates on the hill 7see ,fig4 #dc7 in a chimney1 the top of which is #afj m4 above the ground level of the works1 affording excellent draft4 ,the condensing chamber 7,figs4 #di to #ea7 consists of a vaulted room1 #c4dj m4 wide and #f4fj m4 long1 which is divided into twelve compartments by one longitudinal and five baffle walls4 ,the gases change direction seven times1 and pass over the longitudinal wall six times1 being struck six times by fine sprays of water4 ,the six atomizers for this purpose consume #a4e liter of water per minute1 of which four-fifths is vaporized1 while one-fifth flows off to the lower water basin4 ,by this means #aj to #ae per cent4 of the total flue dust is precipitated in the condensing chamber itself1 and is removed from time to time as mud through the lower openings1 which are water-sealed4 ,the remainder of the volatilized water precipitates the flue dust almost completely on the way to the stack1 so that only a short column of steam is visible at the mouth of the stack4 ,the flue to the stack passes for the most part underground through abandoned adits and galleries1 thus providing a variety of changes in cross-section and in direction1 and assisting materially the action of the condensing chamber4 ,illustration3 ,,fig4 #dg4--,section of ,lead ,refinery4 ,illustration3 ,,fig4 #dh4--,softening ,furnace4 ,as the charge of the shaft furnaces is poor in sulphur1 no real matte is produced1 but only work lead and lead ashes 7,bleischaum71 which contains #ij per cent4 of lead1 #a4f per cent4 sulphur1 #j4d per cent4 zinc1 #j4he per cent4 ,cu1 #j4ii per cent4 ,fe1 and #j4bb per cent4 ,sb4 ,by liquation and a reducing smelt in a reverberatory furnace1 most of the lead is obtained1 along with a lead-copper matte1 which is smelted for copper matte and antimonial lead in the blast furnace4 ,illustration3 ,,fig4 #di4--;,fume ,condenser4 7,section ,a ,b47 ,the copper matte1 containing #ah per cent4 ,cu1 #be per cent4 ,fe1 #cj per cent4 ,pb and #ah4d per cent4 ,s1 is roasted dead in a reverberatory furnace1 is sintered1 and melted to copper-bottoms in a small shaft furnace4 ,these copper-bottoms1 which contain #fj per cent4 copper and #be per cent4 lead1 are subjected to liquation1 and finally refined to blister copper4 ,the zinc-desilvering plant1 ,fig4 #dg1 consists of a reverberatory softening furnace1 two desilvering kettles of #ad tons capacity1 a pan for liquating the zinc crust1 and a small kettle for receiving the lead from the liquation process4 ,this pan has the advantage over the ordinary liquating kettle1 that the lead which drips off is immediately removed1 before it can dissolve the alloy2 the silver content of the liquated lead is scarcely #j4je per cent41 while the dry alloy contains #e to #h per cent4 ,illustration3 ,,fig4 #ej4--;,fume ,condenser4 7,section ,e ,f ,g ,h47 ,illustration3 ,,fig4 #ea4--;,fume ,condenser4 7,section ,c ,d47 ,the removal of the zinc is effected in a second reverberatory furnace4 ,formerly the steam-method was used1 but the rapid wear of the kettles1 and the excessive formation of oxides called for a change in the process4 ,the zinc-silver alloy is distilled in a crucible of #bjj kg4 capacity1 and is cupeled in an ,english cupel furnace4 ,the details of the reverberatory furnace are shown in ,fig4 #dh4 ,the composition of the final products is shown by the following analyses2 ,lead3 ,zn1 #j4jjba per cent42 ,fe1 #j4jjdg per cent42 ,cu1 #j4jjje per cent42 ,sb1 #j4jjcj per cent42 ,bi1 #j4jjjg per cent42 ,ag1 #j4jjaj per cent42 ,pb1 #ii4iih per cent42 ,silver1 ,ag1 #ii4gbj per cent42 ,cu1 #j4aba per cent42 ,fe1 #j4jje per cent42 ,pb1 #j4jah per cent42 ,au1 #j4jjc per cent4 ,,index ,alloy1 retorting the1 in lead refining1 #bfg ,alumina1 experience with1 #bei ,american ,smelting and ,refining ,co41 #d1 #f1 #bf1 #ic1 #aac1 #beb1 #bie at ,murray1 ,utah1 #bhg ,atmosphere1 effect of on concrete1 #bdb ,bag-house1 cost of attending1 #bdf standard1 #bdf ,bag-houses for saving fume1 #bdd ,bartlett1 ,eyre ,o41 #bdd ,bayston1 ,w4 ,b41 #aii ,bennett1 ,james ,c41 #ff ,betts1 ,anson ,g41 #bgj1 #bgd ,between products1 working up of1 #ci ,biernbaum1 ,a41 #da1 #adh1 #afj ,blast furnace of circular form1 #bec ,spanish lead1 #cjg ,blast1 volume and pressure of in lead smelting1 #gf ,blower1 rotary1 deficiency of1 #bea ,blowers for lead and copper smelting1 #bef now more powerful for lead smelting use1 #beb ,blowers1 rotary1 method of testing volumetric efficiency of1 #bed vs4 blowing engines1 #bed vs4 blowing engines for lead smelting1 #bea ,blowing engines1 when to use1 #bei ,bonne ,terre lead deposits1 #ah orebody1 ,missouri1 #ac1 #ad ,borchers1 ,w41 #aad1 #aaf1 #abg ,bormettes method1 combination processes in1 #bbb ,bradford1 ,mr41 #ee ,bretherton1 ,s4 ,e41 #bea1 #beh ,broken ,hill ,proprietary ,block1 #ad1 #ei ,broken ,hill practice1 #ea ,proprietary ,co41 #eb1 #aac1 #abd1 #ade1 #age1 #agh1 #bjf ,bricking plant for flue dust and fine ores1 #ff-gj ,briquetting costs1 #fb methods of avoiding1 #fc1 #fd process1 operations1 in #ei ,bullion1 analyses of in lead refining1 #bha refined lead and slimes1 analyses of1 #bhb ,canadian ,smelting ,works1 #bge ,carlton ,iron ,co41 #fc ,carmichael1 ,a4 ,d4 #ef1 #aii ,carmichael-,bradford process1 #age-ahe brief estimate of1 #bji claims of in patent1 #aii recommendations of1 #abd process1 points concerning1 #aca ,cement walls1 how to build1 #bda ,channing1 ,j4 ,parke1 #bed ,charge-car in smelting1 true function of1 #id feeding of in lead smelting1 #gg mechanical character of in lead smelting1 #gh ,charges1 effect of large in lead smelting1 #gg ,cherokee ,lanyon ,smelter ,co41 #ajd ,chimney bases1 #bcg ,chisholm1 ,boyd ,white ,co41 #fd ,clark1 ,donald1 #aad1 #add1 #age ,cur d',alene mines1 #e1 #f1 #g ,concrete flues and stacks1 advantages and disadvantages of1 #bdb in metallurgical construction1 #bcd ,connersville ,blower ,co41 #beb ,consolidated ,kansas ,city ,smelting and ,refining ,co41 #bhe ,coke1 percentage necessary to use in smelting1 #bei ,croll1 ,h4 ,v41 #bec ,cupellation in lead refining1 #bfi ,de ,lamar ,copper ,refining ,co41 #big ,desilverization in lead refining1 #bfe ,desloge practice contrasted with others1 #df ,doeltz1 ,f4 ,o41 #aci ,dross1 analyses of in lead refining1 #bgi ,dupuis ,sons1 #fc ,dust chamber1 arched form1 #bca beehive form of1 #bcb design1 #bbi rectangular form1 #bcj concrete1 #bce-bcg ,dwight1 ,arthur ,s41 #gc1 #ha spreader and curtain in furnaces1 #ia ,east ,helena and ,pueblo smelting systems compared1 #ic plant of the ,american ,smelting and ,refining ,co41 #cjb system of smelting1 #hh-id ,edwards1 ,henry ,w41 #bcd1 #bdj1 #bdb ,einstein silver mine1 #ad ,engine1 blowing1 proper field of1 #beg blowing1 and rotary blowers1 #beh ,eriksson1 ,hjalmar1 #cjf ,federal ,lead ,co41 #ch ,mining and ,smelting ,co41 #g ,feeders1 cup and cone1 for round furnaces1 #ha ,ferraris1 ,erminio1 #caa ,flat ,river mines1 #ah ,flue gases and moisture1 effect of on concrete1 #bdb ,flues1 concrete1 #bcd1 #bdj1 #bdb ,foundations for dynamos1 #bcf ,fremantle ,smelting ,works1 #ade ,fume-smelting1 cost of1 #cc in the hearth1 #cb ,furnace operations at ,desloge1 ,mo41 #de ,furnaces at ,desloge1 ,mo41 #dc reverberatory1 at ,desloge1 ,mo41 #db ,galena1 experiments in roasting1 #abi lime-roasting of1 #ad new methods of desulphurizing1 #aaf roasting of by ,savelsberg process1 #abb1 #abc ,gas1 furnace1 effect of on cement1 #bdj ,gelatine1 use of in electrolytic lead refining1 #bge ,germot1 ,a41 #bbd process1 #bbd ,globe plant of the ,american ,smelting and ,refining ,co41 #cjd ,smelting and ,refining ,co41 #bdd ,greenway1 ,t4 ,j41 #ei ,guillemain1 ,c41 #acc ,harvard1 ,francis ,t41 #bdb ,hearth1 covered-in1 #cf ,heat1 effect of on cement1 #bdb ,heberlein1 ,ferdinand1 #aac1 #afg1 #aii ,hixon1 ,hiram ,w41 #bef1 #beh ,harwood1 ,e4 ,j41 #ea ,hourwich1 ,dr4 ,isaac ,a41 #bg ,huntington-,heberlein process1 #aac1 #add-adg consideration and estimate of1 #bjc-bji credit due to1 #abf process as distinguished from others1 #aah economic results of1 #aee-aei ,huntington-,heberlein explained by the inventors1 #afg-agc process at ,friedrichshtte1 #adh process1 from the hygienic standpoint1 #afj ideas of in patent specifications1 #aag process1 introduction of at ,tarnowitz1 ,prussia1 #da and ,savelsberg processes1 essential difference between1 #aib process1 some disadvantages of1 #afe1 #aff ,huppertz1 ,l41 #aba ,hutchings1 ,w4 ,maynard1 #ajh1 #abf1 #agj ,huntington1 ,thomas1 #aac1 #afg1 #aii ,iles1 ,malvern ,w41 #if1 #beb ,ingalls1 ,w4 ,r41 #c1 #af1 #bg1 #db1 #agg1 #ahf1 #aic1 #bae1 #bbd1 #bdd1 #bhg ,iron1 behavior of in silver-lead smelting1 #ge ,jackson ,revel mine1 #ad ,johnson1 ,e4 ,m41 #ajd ,r4 ,d4 ,o41 #ah ,jones1 ,richard1 #bdd ,samuel ,t41 #bdd ,laur1 ,f41 #bbd ,lead1 analyses of refined1 #bha bullion1 electrolytic refining of base1 #bgj bullion1 ,parkes process of desilverizing and refining1 #bfc bullion1 softening of1 #bfc concentrate ,joplin district1 valuation of1 #be and copper smelting1 the ,bormettes method of1 #bae-bbc deposits1 southeastern ,missouri1 #ah ,joplin district1 #h marketing1 #c -ore roasting1 consideration of new processes1 #ace-ach ,lead ore1 average prices for1 #bg ore1 cost of smelting1 #cb -ore roasting1 theoretical aspects of1 #acc ores1 ,galena1 ,kan41 #bd ores1 method of valuing1 #bf ores1 southwestern ,missouri1 #bd ,park ,city1 ,utah1 #h -poisoning in old and new processes1 #afb-afe refining1 electrolytic1 #bgd soft1 ,missouri1 #be smelting at ,desloge1 ,mo41 #db smelting at ,monteponi1 ,sardinia1 #caa smelting and refining1 cost of1 #if smelting in the ,scotch hearth1 #ca smelting in ,spain1 #cjf smelting at ,tarnowitz1 ,prussia1 #da source of in ,missouri1 #ac in southeastern ,missouri1 #g1 #aj1 #ag sulphide and calcium sulphate1 metallurgical behavior of1 #aci-adc total production ,united ,states1 #e yield from ,scotch hearths1 #ci ,leadville1 ,colo41 mines1 #h ,lewis1 ,g4 ,t41 #bdd ,lime-roasting of galena1 #abf ,lotti1 ,alfredo1 #bae ,messiter1 ,edwin ,h41 #bbi1 #bdj ,middleton1 ,k4 ,w4 ,m41 #ca ,mine ,la ,motte1 #ad ,minerals1 briquetting of1 #fc ,mining methods in ,missouri1 #ai-bc ,missouri ,smelting ,co41 #aig ,mould1 ,h4 ,s41 ,co41 #fd ,murray smelter1 ,utah1 #bia ,national plant of the ,american ,smelting and ,refining ,co41 #bii ,new ,jersey ,zinc ,co41 #bdf ,nutting1 ,mr41 #bef ,ore and ,fuel ,co41 #fc different behavior of coarse and fine in lead smelting1 #gi treatment in detail by the ,huntington-,heberlein process1 #aej-aee ,parkes process1 cost of refining by1 #ii ,percy1 ,dr41 #bdd ,perth ,amboy plant of the ,american ,smelting and ,refining ,co41 #bif ,petraeus1 ,c4 ,v41 #bd ,pfort curtain for furnaces1 #hb ,picher ,lead ,co41 #aig ,piddington1 ,f4 ,l41 #bfc ,potter1 ,prof4 ,w4 ,b41 #ae ,pueblo lead smelter1 #bid ,smelting and ,refining ,co41 #hd ,pufahl1 ,o41 #ch1 #bia1 #bid1 #bif1 #bii1 #cjb1 #cjd ,pyritic smelting without fuel practically impossible1 #bef ,raht1 ,august1 #bea1 #bed ,refining1 monthly cost of per ton of bullion treated1 #ajj ,roasters1 hand1 and mechanical furnaces1 average monthly cost of1 #ih ,roberts-,austen1 ,w4 ,c41 #aci ,salts1 effect of crystallization of contained on concrete1 #bdc ,santa ,fe ,gold and ,copper ,mining ,co41 #bee ,savelsberg1 ,adolf1 #abb ,savelsberg process1 #ahf-aib process1 claims of in patent1 #bja process contrasted with ,huntington-,heberlein1 #bji process1 difference between and ,huntington-,heberlein1 #aig ,savelsberg process the simplest1 #acb ,scotch-hearth method1 permanency of1 #aie ,scotch hearths1 #cd ,schneider1 ,a4 ,f41 #ha ,seattle ,smelting and ,refining ,works1 #bgc ,silver-lead blast furnaces1 mechanical feeding of1 #ha blast furnace1 proper conditions1 #gc smelting1 details of practice1 #gc smelting1 modern1 #gc ,slag-smelting costs1 #cd ,slime analysis at ,broken ,hill1 #ea ,slimes1 analyses of in lead refining1 #bha desulphurization of by heap roasting1 #ea treatment of at ,broken ,hill1 #ec-ee ,smelter1 new1 at ,el ,paso1 ,texas1 #bhe ,smelters' pay1 #cb ,smelting1 average cost of per ton1 #ih ,smelting ,co4 of ,australia1 #bfc costs1 #dh detailed costs of1 #aja1 #ajb of galena ore1 #ch preparation of fine material for1 #ei ,solution1 washing from slime1 #bgg ,sticht1 ,mr41 #bef ,st4 ,joseph ,lead ,co41 #af ,st4 ,louis ,smelting and ,refining ,co41 #ha ,sulphide ,corporation1 #ade ,sulphur dioxide1 effect of on cement1 #bdj ,sulphuric acid1 making of at ,broken ,hill1 #agd ,tasmanian ,smelting ,co41 #ade ,tennessee ,copper ,co41 #bee ,terhune1 ,r4 ,h41 furnace gratings1 #hd ,thacher1 ,arthur1 #ad ,ulke1 ,titus1 #bgj ,united ,smelting and ,refining ,co41 #hh ,states ,zinc ,co41 #bie ,vezin1 ,h4 ,a41 #beb ,walls1 retaining1 #bcg ,walter1 ,e4 ,w41 #bfj ,waring1 ,w4 ,geo41 #bd ,welch1 ,max ,j41 #bbi ,wetherill1 ,samuel1 #bdd ,wheeler1 ,h4 ,a41 #aj ,zinc1 amount required in lead refining1 #bfe1 #bff crusts1 treatment of in lead refining1 #bfg oxide in slags1 #ajh retort residues1 analysis of materials smelted and bullion produced1 #ajf retort residues1 smelting1 #ajd ,,footnotes3 #a ,during #aije1 antimonial lead commanded a premium of about #a;c4 per lb4 above desilverized1 owing to the high price for antimony4 #b ,the figures for #aijc and #aijd have been added in the revision of this article for this book4 ,the production of lead in the ,united ,states in #aijc was #bgf1fid tons2 in #aijd1 it was #cjb1bjd tons4 #c ,ounces of silver to the ton of lead4 #d ,these figures are doubtful2 they are probably too high4 7,see table on p4 #e74 #e ,the production of zinc ore in this district has now been commenced4 #f ,the manuscript of this article was dated ,oct4 #e1 #aije4 #g ,translated from ,zeit4 f4 ,berg4-,htten-und ,salinenwesen1 ,,liii 7#aije1 p4 #dej74 #h ,this paper is published in pp4 #adh-aff of this book4 #i ,abstract from ,transactions of the ,australasian ,institute of ,mining ,engineers1 ,vol4 ,,ix1 ,part #a4 #aj ,in the course of subsequent discussion ,mr4 ,horwood stated that the losses in roasting were #ab per cent4 in lead and probably about #e per cent4 in silver4 ,as compared to roasting in ,ropp furnaces the loss in lead was #e to #f per cent4 greater1 but the difference of loss in silver was1 he thought1 not appreciable4 ,mr4 ,hibbard said that the ,central mine had obtained satisfactory results with masonry kilns4--,,editor4 #aa ,abstract of portion of a paper presented at the ,mexican meeting of the ,american ,institute of ,mining ,engineers1 under the title 8,the ,mechanical ,feeding of ,silver-,lead ,blast ,furnaces40 ,transactions1 ,vol4 ,,xxxii1 pp4 #cec-cie4 #ab ,abstract of a paper 78,the ,mechanical ,feeding of ,silver-,lead ,blast ,furnaces07 presented at the ,mexican meeting of the ,american ,institute of ,mining ,engineers and published in the ,transactions1 ,vol4 ,,xxxii4 ,for the first portion of this paper see the preceding article4 #ac ,abstract of a paper in ,western ,chemist and ,metallurgist1 ,i1 ,,vii1 ,aug41 #aije4 #ad ,much better work is being done at present1 smelting the ,western zinc ores1 and the residue contains about one-third of the above figure1 or #g4e per cent4 of zinc oxide4 ,the high per cent4 of ,zn,o left in residue was mainly due to poor roasting4 #ae ,there was also considerable coke used of an inferior grade1 made from ,kansas coal4 #af ,part of the ,zn,o in roasted matte came from being roasted in the same furnace the zinc ore had been roasted in4 #ag ,there was less residue on the charges during this month1 which accounts for the larger tonnage with a lower blast4 #ah ,translation of a paper read before the ,naturwissenschaftlicher ,verein at ,aachen1 and published in ,metallurgie1 #aije1 ,,ii1 i1 #a-f4 #ai #ce to #dj cm4 #ac4gh to #ae4ge in4 #h to #i4ab oz4 per sq4 in4 #bj ,engineering and ,mining ,journal1 #aijd1 ,,lxxviii1 p4 #fcj2 article by ,donald ,clark2 reprinted in this work1 p4 #add4 #ba ,owner of the patents4--,,editor4 #bb ,abstract of a paper in ,metallurgie1 ,,ii1 #ah1 ,sept4 #bb1 #aije1 p4 #dcc4 #bc ,this method is described further on in this book4 #bd ,translated from ,metallurgie1 ,vol4 ,,ii1 ,no4 #ai4 #be ,british patent1 ,no4 #ag1ehj1 ,jan4 #cj1 #aijb1 8,improved process for desulphurizing sulphide ores40 #bf ,w4 ,c4 ,roberts-,austen1 8,an ,introduction to the ,study of ,metallurgy10 ,london1 #aijb4 #bg ,a4 ,lodin1 ,comptes rendus1 #ahie1 ,,cxx1 #aafd-aafg2 ,berg4 u4 ,httenm4 ,ztg41 #aijc1 p4 #fc4 #bh ,comptes rendus1 loc4 cit4 #bi ,translated from the ,zeitschrift fr das ,berg4-,htten-und ,salinenwesen im4 preuss4 ,staate1 #aije1 ,,liii1 ii1 pp4 #bai-bcj4 #cj ,translated from the ,zeitschrift fr das ,berg4-,htten-und ,salinenwesen im4 preuss4 ,staate1 #aije1 ,,liii1 ii1 pp4 #bai-bcj4 #ca ,the manufacture of sulphuric acid from these gases has now been undertaken in ,silesia on a working scale4--,,editor4 #cb ,a paper presented before the ,american ,institute of ,mining ,engineers1 ,july1 #aijf4 #cc ,engineering and ,mining ,journal1 ,sept4 #b1 #aije4 #cd ,this term is inexact1 because the hearths employed in the ,united ,states are not strictly 8,scotch hearths10 but they are commonly known as such1 wherefore my use of the term4 #ce ,percentages of lead in ,missouri practice are based on the wet assay2 among the silver-lead smelters of the ,west the fire assay is still generally employed4 #cf ,this improvement did not originate at either ,alton or ,collinsville4 ,it had previously been in use at the works of the ,missouri ,smelting ,company at ,cheltenham1 ,st4 ,louis1 but the idea originated from the practice of the ,picher ,lead ,company1 of ,joplin1 ,mo4 #cg ,this refers especially to the ,savelsberg process4 #ch ,a4 ,d4 ,carmichael1 ,u4 ,s4 patent ,no4 #gje1ijd1 ,july #bi1 #aijb4 #ci ,metallurgie1 #aije1 ,,ii1 i1 #a-f2 ,engineering and ,mining ,journal1 ,sept4 #b1 #aije4 #dj ,metallurgie1 #aije1 ,,ii1 #ai2 ,engineering and ,mining ,journal1 ,jan4 #bg1 #aijf4 #da ,metallurgie1 #aije1 ,sept4 #bb1 #aije2 ,engineering and ,mining ,journal1 ,march #aj1 #aijf4 #db ,engineering and ,mining ,journal1 ,oct4 #ba1 #aije4 #dc ,translated by ,w4 ,r4 ,ingalls4 #dd ,as originally published the title of this article was 8,lead-,smelting without ,fuel40 ,in this connection reference may well be made to ,hannay's experiments and theories1 ,transactions ,institution of ,mining and ,metallurgy1 ,,ii1 #ahh1 and ,huntington's discussion1 ibid41 p4 #bag4 #de ,excerpt from a paper1 8,concrete in ,mining and ,metallurgical ,engineering10 ,transactions ,american ,institute of ,mining ,engineers1 ,,xxxv 7#aije71 p4 #fj4 #df ,a ,discussion of the ,paper by ,henry ,w4 ,edwards1 on 8,concrete in ,mining and ,metallurgical ,engineering10 ,transactions of the ,american ,institute of ,mining ,engineers1 ,,xxxv4 #dg ,engineering ,news1 ,nov #cj1 #ahii1 and ,u4 ,s4 ,patent ,no4 #ffe1bej1 ,jan4 #a #aija4 #dh ,a discussion of the paper of ,henry ,w4 ,edwards1 on 8,concrete in ,mining and ,metallurgical ,engineering10 ,transactions of the ,american ,institute of ,mining ,engineers1 ,,xxxv4 #di ,abstract from the ,journal of the ,chemical1 ,metallurgical and ,mining ,society of ,south ,africa1 ,may1 #aijc4 #ej ,abstract of a paper in ,transactions ,american ,institute of ,mining ,engineers1 ,,xxxiv 7#aijd71 p4 #age4 #ea ,silver not given4 ,this was the case1 also1 with the gold in the bullion4 ,the slimes contained #j4aca per cent4 of gold1 or #ci4a oz4 per ton4 #eb ,a constituent company of the ,american ,smelting and ,refining ,company4 #ec ,translated from ,zeit4 f4 ,berg4-,htten4-und ,salinenwesen im preuss4 ,staate1 #aije1 ,,liii1 p4 #dcc4 #ed ,abstract from a paper in ,zeit4 f4 ,berg4-,htten-und ,salinenwesen im preuss4 ,staate1 #aije1 ,,liii1 p4 #dci4 #ee ,translated from ,zeit4 f4 ,berg4-,htten4-und ,salinenwesen im preuss4 ,staate1 #aije1 ,,liii1 #dij4 #ef ,abstract from a paper in ,zeit4 f4 ,berg4-,htten-und ,salinenwesen im preuss4 ,staate1 #aije1 p4 #djj4 #eg ,abstract from a paper in ,zeit4 f4 ,berg4-,htten4-und ,salinenwesen im preuss4 ,staate1 #aije1 p4 #djj4 #eh ,abstract from an article in ,zeit4 f4 ,berg4-,htten4-und ,salinenwesen im preuss4 ,staate1 #aije1 ,,liii1 p4 #ddd4 #ei ,translated from ,oest4 ,zeit4 f4 ,berg4-und ,httenwesen1 #aije1 p4 #dee4