,,modern ,,copper ,,smelting4 ,the ,colour of the ,converter ,flame during the ,bessemerising of ,copper ,matte4 ,illustration3 ,,fig4 #a4 ,flame at commencement of blow4 ,illustration3 ,,fig4 #b4 ,flame during the first or 8slagging0 stage4 ,illustration3 ,,fig4 #c4 8,white ,metal stage40 ,slagging of ,copper4 ,illustration3 ,,fig4 #d4 ,flame during second or 8blowing to blister0 stage4 ,,modern ,,copper ,,smelting4 ,,being ,,lectures ,,delivered ,,at ,,birmingham ,,university ,,greatly ,,extended ,,and ,,adapted1 ,,and ,,with ,,an ,,introduction ,,on ,,the ,,history1 ,,uses ,,and ,,properties ,,of ,,copper4 ,,by ,,donald ,m4 ,,levy1 ,m4,sc41 ,assoc4 ,r4,s4,m41 ,,assistant ,,lecturer ,,in ,,metallurgy1 ,,university ,,of ,,birmingham4 ,with frontispiece1 and #gf illustrations4 ,illustration ,,london3 ,,charles ,,griffin ,,company1 ,,limited2 ,,exeter ,,street1 ,,strand4 #aiab4 ,all ,rights ,reserved4 ,,preface4 ,the lectures on 8,modern ,copper ,smelting0 embodied in this volume were delivered at the ,university of ,birmingham to the ,senior ,students in the ,school of ,metallurgy and to others interested in the subject4 ,they are based largely upon the results of a study of the practice as conducted at a number of the best organised smelters and refineries in the ,united ,states of ,america1 at which the author has had the opportunity of spending some considerable time1 and it has been felt that there exists a scope1 particularly on this side of the ,atlantic1 for a compact volume dealing broadly with the principles underlying ,modern ,copper ,smelting1 illustrated with such examples of working practice from personal observation4 ,the subject-matter of the ,lectures has been extended by the addition of an ,introduction on the ,history1 ,uses1 and ,general ,metallurgy of ,copper as applied to ,modern ,practice4 ,the ,copper ,industry is already fortunate in the literature at its disposal4 ,it possesses standard works of reference through the publication of ,dr4 ,peters' classical volumes on the ,principles of ,copper ,smelting1 and more recently 7during the preparation of the present work7 of the volume on the ,practice of ,copper ,smelting--works which have done much to raise copper smelting to a science4 ,the industry is being rendered invaluable service by the ,technical ,societies and ,technical ,press1 whose publications furnish an admirable record of the constant advance in the theory and practice of the art4 ,use has been made of these sources of information in the present work1 and lists of such references are appended to each of the ,lectures4 ,grateful acknowledgment is made to several authors and editors who have given permission for the reproduction of illustrations or for the inclusion of references3--,dr4 ,peters1 ,professor ,gowland1 ,mr4 ,hughes1 the ,editors of the ,engineering and ,mining ,journal1 ,mineral ,industry1 ,mines and ,minerals1 and others4 ,the ,institution of ,mining and ,metallurgy1 ,messrs4 ,chambers ,bros41 ,the ,traylor ,engineering ,co41 and the ,power and ,mining ,machinery ,co4 have very kindly provided blocks for several of the illustrations2 the ,anaconda ,copper ,mining ,co4 furnished a set of photographs1 whilst ,figs4 #h1 #cg1 and #gf have been reproduced by permission of the ,american ,institution of ,mining ,engineers4 ,to the ,superintendents and ,staffs of the several smelters where opportunities were so freely given for studying modern practice1 and particularly to ,mr4 ,e4 ,p4 ,mathewson at ,anaconda1 ,montana1 to ,mr4 ,j4 ,parke ,channing at the ,tennessee ,copper ,company's ,smelter1 and to ,mr4 ,w4 ,h4 ,freeland at ,ducktown1 ,tennessee1 the author desires to express his appreciation for much valued information and many other kind services4 ,the frequent references made in this book to the organisation and the methods employed at these works is not only a tribute to the useful information freely imparted1 but is also due to the fact that such features are so thoroughly representative of the most advanced practice in copper smelting upon a large scale and of the direction in which all modern work is undoubtedly tending4 ,the author further thanks ,professor ,turner of ,birmingham ,university for his interest in this volume1 ,mr4 ,frank ,levy for reading the proofs1 and the publishers1 ,messrs4 ,charles ,griffin ,co41 ,ltd41 for the care taken in the preparation and production of the work4 ,,university ,,of ,,birmingham1 ,may1 #aiab4 ,,contents4 ,,lecture ,i4 ,,pages ,history of ,copper -- ,development of the ,copper ,industry -- ,progress of ,smelting ,practice -- ,price and ,cost of ,production of ,copper -- ,copper ,statistics1 #a-ag ,,lecture ,,ii4 ,the ,uses of ,copper3 as ,metal and as ,alloy -- ,the ,physical ,properties of ,copper -- ,effects of ,impurities -- ,mechanical ,properties -- ,chemical ,properties1 #ah-cd ,,lecture ,,iii4 ,compounds of ,copper -- ,copper ,mattes -- ,the ,varieties of ,commercial ,copper -- ,ores of ,copper -- ,preliminary ,treatment of ,ores -- ,sampling1 #ce-ej ,,lecture ,,iv4 ,modern ,copper ,smelting ,practice -- ,preliminary ,treatment of ,ores3 ,concentration1 ,briquetting1 ,sintering -- ,the ,principles of ,copper ,smelting -- ,roasting1 #ea-hj ,,lecture ,v4 ,reverberatory ,smelting ,practice3 -- ,functions of the ,reverberatory ,furnace -- ,requirements for ,successful ,working -- ,principles of ,modern ,reverberatory ,practice -- ,operation of ,modern ,large ,furnaces -- ,fuels for ,reverberatory ,work2 ,oil ,fuel2 ,analysis of ,costs -- ,condition of the ,charge1 #ha-aab ,,lecture ,,vi4 ,blast-,furnace ,practice3 -- ,functions of the ,furnace -- ,reduction ,smelting -- ,oxidation in the ,furnace -- ,the ,pyritic ,principle -- ,features of ,modern ,working3 ,water-,jacketing1 ,increase in ,furnace ,size1 ,external ,settling -- ,constructional ,details of the ,furnace1 #aac-ade ,,lecture ,,vii4 ,modern ,blast-,furnace ,practice 7continued73 -- ,charge ,calculations -- ,working -- ,disposal of ,products -- ,pyritic ,smelting -- ,sulphuric ,acid ,manufacture from ,smelter ,gases1 #adf-aia ,,lecture ,,viii4 ,the ,bessemerising of ,copper ,mattes3 -- ,development of the ,process -- ,the ,converter -- ,converter ,linings -- ,grade of ,matte -- ,operation of the ,process -- ,systems of ,working1 #aib-baf ,,lecture ,,ix4 ,the ,purification and ,refining of ,crude ,copper3 -- ,preliminary ,refining and ,casting into ,anodes -- ,electrolytic ,refining -- ,bringing to ,pitch1 and ,casting of ,merchant ,copper1 #bag-bdc ,,index1 #bde-bei ,,list ,,of ,,illustrations4 ,,frontispiece--,the ,colour of the ,converter ,flame during the ,bessemerising of ,copper ,matte4 ,,page ,fig4 #a4--;,fluctuations in the ,price of ,best ,select ,copper1 #ab #b4--;,annual ,production of ,copper1 #af #c4--;,equilibrium ,diagram1 ,cu-,zn ,series1 #bb #d4--;,influence of ,arsenic and ,antimony on the ,electrical ,conductivity of ,copper1 #be #e4--,relations of ,copper and ,oxygen1 #bg #f4--,microstructure of ,copper containing ,oxygen 7,heyn71 ,plate to face #bh #g4--,relations of ,copper and ,arsenic1 #bi #h4--;,freezing-,point ,curve of ,iron-,copper ,sulphides 7,mattes71 #ch #i4--,outline of ,sampling ,scheme1 ,anaconda1 #dh #aj4--,section through ,sampling ,mill1 #dh #aa4--;,brunton ,sampler1 #di #ab4--,outline of ,smelting ,scheme at the ,anaconda ,smelter1 ,montana1 ,u4 ,s4 ,a41 #ed #ac4--,sketch ,plan of ,briquetting ,plant1 #ef #ad4--,section through ,auger-,former1 showing ,briquetting ,mechanism of ,chambers' ,machine1 #ef #ae4--;,chambers' ,briquette-making ,machine1 ,plate to face #eg #af4--;,dwight-,lloyd ,sintering ,machine1 #fj #ag4--,o',harra ,furnace 7,fraser-,chalmers71 illustrating ,principle of ,mechanical ,rabbling by ,travelling ,ploughs1 #ga #ah4--,section through ,mechanically ,rabbled ,roaster ,furnace 7illustrating ,improvements for ,protecting ,driving ,mechanism71 #ga #ai4--,mac,dougal ,roaster--,vertical ,section1 #gd #bj4--;,herreshof ,furnace--,section indicating ,connections for ,cooling ,rabbles and ,spindles1 #gd #ba4--,spindle ,connections and ,guide ,shields of ,evans-,klepetko ,roasters1 #gf #bb4--,rabble-blades and ,bases1 #gg #bc4--;,development of the ,reverberatory ,furnace 7,gowland71 #ij #bd4--;,draft ,pressure ,record of ,anaconda ,reverberatory ,furnace1 #id #be4--,skimming ,reverberatory ,furnace1 ,anaconda1 ,plate to face #if #bf4--,transverse ,section of ,modern ,reverberatory ,furnace1 ,anaconda1 indicating ,foundations1 ,hearth1 and ,bracing1 #if #bg4--,reverberatory ,furnace under ,construction1 ,plate to face #if #bh4--,sectional ,plan and ,elevation of ,reverberatory ,furnace at ,anaconda1 #ih #bi4--;,fire-box ,end of ,reverberatory ,furnace1 showing massive ,bracing1 ,charge ,bins1 and ,charging ,levers1 ,anaconda1 ,plate to face #ajj #cj4--;,interior of ,reverberatory ,furnace 7looking towards ,skimming ,door71 showing ,expansion ,spaces in ,roof1 and ,charging ,holes1 ,anaconda1 ,plate to face #ajj #ca4--,shelby ,oil-,burner for ,reverberatory ,furnace ,use1 #ajf #cb4--,modern ,blast-,furnace ,shell of ,sectioned ,jackets 7,p4 ,m4 ,m4 ,co471 ,plate to face #abb #cc4--;,blast-,furnaces under ,construction1 showing ,fixing of ,jackets1 ,bottom ,plate1 ,method of ,support1 ,sectioning1 etc4 7,t4 ,e4 ,co471 ,plate to face #abd #cd4--;,development of the ,blast ,furnace 7,gowland71 #abf #ce4--,plan of #ea-;foot ,blast ,furnace1 ,anaconda1 indicating ,position of ,crucibles1 ,spouts1 and ,connecting ,bridge between ,old ,furnaces1 #abh #cf4--,longitudinal ,section and ,part ,elevation of #hg-;foot ,blast-,furnace1 ,anaconda1 indicating ,crucibles of ,old ,furnaces1 ,bridge1 and ,jacketing1 #abh #cg4--;,copper ,contents in the ,slags accompanying ,mattes of ,various ,grades1 #acb #ch4--,water-,jacketed ,blast ,furnace1 lower portion indicating ,air and ,water ,connections1 ,bottom ,supports1 ,end ,slag ,spouts1 etc4 7,p4 ,m4 ,m4 ,co471 ,plate to face #acd #ci4--,tapping ,breast of ,blast ,furnace1 ,cananea1 #acf #dj4--,rivetted ,steel ,water-,jacket1 showing ,tuyere ,holes and ,water ,inlets1 etc4 7,p4 ,m4 ,m4 ,co471 #acg #da4--,transverse ,section through ,modern ,blast ,furnace1 showing ,arrangements of ,boshed ,lower ,jackets1 ,upper ,jackets1 and ,plates1 ,stays and ,supports1 etc41 #ach #db4--;,interior of ,anaconda ,blast ,furnace1 showing ,jacketing1 ,tuyere ,holes1 and ,bridge1 ,plate to face #ach #dc4--,showing ,upper ,jackets1 ,apron and ,mantle ,plates and ,superstructure of ,blast ,furnace1 ,anaconda1 ,plate to face #adj #dd4--;,charging ,blast ,furnaces1 ,anaconda1 ,plate to face #adj #de4--;,blast-,furnace ,shell1 with ,air ,connections 7,p4 ,m4 ,m4 ,co471 #adb #df4--;,details of ,tuyere1 ,cananea ,blast ,furnace1 #adb #dg4--,v-,shaped ,charging ,car1 indicating ,mechanism for ,release and ,tilting1 #aec #dh4--;,end ,view of ,blast ,furnace1 showing ,tilting of ,charge ,car1 ,anaconda1 #aee #di4--;,hodge's ,charging ,car1 #aee #ej4--;,freeland ,charging ,machine 7,d4 ,s4 ,c4 ,i4 ,co471 #aeg #ea4--;,freeland ,charger-,details1 #aeg #eb4--,slag ,spout1 showing ,method of ,trapping ,blast1 also ,replaceable ,nose-,piece of ,spout 7,a71 #aei #ec4--;,details of ,slag ,spout1 ,cananea1 #afa #ed4--,slag ,spout1 showing ,method of ,support1 #afa #ee4--;,general ,view of ,settler 7,t4 ,e4 ,co471 #afc #ef4--,method of ,lining ,settler1 ,cananea1 #afc #eg4--;,arrangement for ,matte and ,slag ,discharge from ,settlers 7,t4 ,c4 ,c471 #afd #eh4--,tap-hole ,casting and ,detail for ,settlers1 #afe #ei4--;,anaconda ,blast ,furnace 7#ea feet long71 showing ,settlers1 ,plate to face #aff #fj4--;,hoppers of ,flue-,dust ,chambers and ,tracks for ,cars underneath1 #afg #fa4--,slotted ,tuyeres1 #ab inches by #d inches 7,t4 ,c4 ,c471 #ahe #fb4--,sectional ,elevation and ,plan of ,barrel-,shaped ,silica-,lined ,converter 7,peters71 #aif #fc4--,latest ,form of ,silica-,lined ,barrel ,converter1 #aig #fd4--,longitudinal ,section of ,basic-,lined ,converter1 #aih #fe4--;,basic-,lined ,converter1 indicating ,tuyeres1 ,lining1 c41 #aii #ff4--;,composition of a ,charge during ,bessemerising ,operation1 #bjh #fg4--,pouring ,slag1 ,anaconda1 #bji #fh4--;,general ,view of ,converter ,shop1 ,anaconda1 ,plate to face #bad #fi4--,sectional ,plan1 ,elevation1 and ,transverse ,sections of ,refining and ,anode-,casting ,furnace1 ,anaconda 7,peters71 #bbj #gj4--;,indicating ,tilting and ,pouring ,mechanism of ,ladle of ,casting and ,refining ,furnaces1 #bbe #ga4--,walker's ,anode-,casting ,machine1 ,plate to face #bbf #gb4--;,general ,view of ,tank-room of ,electrolytic ,refinery 7,perth ,amboy1 ,n4,j471 ,plate to face #bbf #gc4--;,indicating ,methods of ,suspending and ,connecting ,electrodes 7,perth ,amboy1 ,n4,j471 #bcd #gd4--;,indicating ,connections for ,circulation of ,electrolyte 7,barnett71 #bce #ge4--,tank-house1 showing ,anode ,crane 7,ulke71 #bcg #gf4--,microstructure of ,commercial ,copper containing ,oxygen 7,hofman71 ,plate to face #bdb ,,tables4 ,,table ,,page ,i4 ,the ,production of ,copper1 #ae ,,ii4 ,north ,american ,production of ,copper1 #ag ,,iii4 ,influence of ,impurities on the ,electrical ,conductivity of ,copper1 #bc ,,iv4 ,analysis of ,various ,commercial ,coppers1 #dd ,v4 ,development in ,size of the ,reverberatory ,furnace1 #hi ,,vi4 ,daily ,reports4 ,reverberatory ,furnaces1 #ajb ,,vii4 ,daily ,assay ,report4 ,reverberatory ,furnaces1 #ajc ,,viii4 ,monthly ,report4 ,reverberatory ,furnaces1 #ajd ,,ix4 ,effect on ,coke ,consumption of ,increased ,sulphur in the ,furnace ,charge1 #abj ,x4 ,blast-,furnace ,charge ,calculations1 #aea ,,xi4 ,typical ,charging ,tables at ,pyritic ,smelter1 #ahg ,,xii4 ,changes in ,composition during ,bessemerising1 #bjf ,,copper ,,smelting4 ,,lecture ,i4 ,history of ,copper -- ,development of the ,copper ,industry -- ,progress of ,smelting ,practice -- ,price and ,cost of ,production of ,copper -- ,copper ,statistics4 ,the ,history of ,copper4--,copper was probably the earliest metal commonly employed by mankind4 ,it occurs in the native condition in various parts of the world1 and the natural product thus required no metallurgical treatment prior to use4 ,its malleability and the property of being readily toughened by simple mechanical treatment were also factors which account for the discovery of its general usefulness in such primitive times4 ,although silver and gold were possibly known even earlier1 these metals appear to have been employed chiefly for ornamental purposes1 and as tokens1 rather than for general service4 ,the alloy of copper and tin1 known as bronze1 was the first metallic combination in common use by man2 its employment was so characteristic in prehistoric times1 that archologists assign to one of the epochs the name of the ,bronze ,age4 ,as is well known1 archological time is marked by a series of ages1 in which the use1 first of stone1 then of bronze1 and ultimately of iron for the manufacture of tools and implements1 indicate the development of industrial culture4 ,the dates which can be assigned to those periods vary with the locality2 the races in the more ,northerly latitudes being later in their development4 ,in our own country1 the ,stone ,ages may be said to date from #cjjj ,b4,c4 down to #ajjj ,b4,c41 and the ,early and ,late ,bronze ,ages from #ajjj ,b4,c4 to #ejj ,b4,c41 and from #ejj ,b4,c4 to the commencement of the present era1 respectively4 ,it is not unlikely that in many places copper was largely used during the ,stone ,ages and before the ,bronze epoch1 since it was only after the art of making fire had been discovered that it became possible to manufacture bronze1 whilst native copper could be fashioned without the aid of heat4 ,metallic relics of the ,bronze ,age1 in the form of arms1 ornaments1 and domestic implements have been found in widely distributed localities4 ,the mention of copper occurs in the ,hebrew ,scriptures1 the metal being termed ,nehosheth1 from the root ,nahsh1 to glisten4 ,this was translated as 7chalcos7 in the ,septuagint1 and ,aes in the ,vulgate2 the ,greeks and ,romans using the terms1 however1 both for copper and for the alloys brass and bronze4 ,according to ,pliny1 the ,roman supply was derived chiefly from ,cyprus1 and the metal thus came to be known as ,aes ,cyprium1 which was gradually shortened to ,cyprium1 a name afterwards corrupted to ,cuprum1 from which are derived our modern terms ,copper1 the ,german ,kupfer1 and the ,french ,cuivre4 ,copper was well known to the alchemists1 and inasmuch as it was largely obtained from ,cyprus1 an island dedicated to ,venus1 it was considered to be the metal specially sacred to the ,goddess1 and was generally known by that name in their writings1 and symbolised by the sign symbol3 circle with plus sign underneath4 ,the production of metallic copper on iron by the action of certain liquors from the ,hungarian mines and other localities1 was likewise known to the alchemists1 and was a constant source of inspiration to them2 the changes were regarded for some hundreds of years as examples of the transmutation of the elements1 until ,boyle showed that it was necessary to introduce copper into such solutions before that metal could be precipitated from them4 ,the ,development of the ,copper ,industry4--,the mining and smelting of copper ores on a primitive scale have been carried on from time immemorial2 these operations were certainly practised in ,greek and ,roman days1 and the deposits of ,britain are said to have been known to the ,phnicians so far back as #ajjj ,b4,c4 ,percy refers to the finding of lumps of copper weighing #db lbs41 carrying a ,roman inscription2 this metal was found in close proximity to mines in ,north ,wales1 which yielded an easily reducible ore1 and he concluded that this was smelted in situ by the ,romans4 ,there are undoubted records of copper mining in this country in the time of ,edward ,,iii41 and in that of ,elizabeth2 whilst the first authentic accounts of copper smelting date also from the latter period1 relating to ,south ,wales4 ,it appears that one of the earliest establishments was situated at ,neath--a fact recorded in a publication of #afjb4 ,the works probably existed for a century before that date1 and the copper smelters at ,swansea were established about #abj years afterwards4 ,the processes employed for the primitive smelting of copper ores were1 to a large extent1 of the same nature as the crude operations practised generally for the extraction of metals in remote ages and by primitive races1 as recorded from time to time by travellers and explorers4 ,the furnace-hearth was a hole in the ground1 working usually on oxide ores with charcoal or wood as fuel4 ,this primitive furnace was later developed1 by the addition of walls for enclosing the charge1 until the 8shaft furnace0 provided with an air blast of some kind was attained4 ,the sulphide ores presented rather more difficulty in their treatment1 but the production of metallic copper from sulphide materials by super-oxidation1 in a process akin to the bessemerising of to-day1 was developed in ,japan centuries ago1 and has been described by ,professor ,gowland4 ,it would appear that during the middle ages1 the art of reducing copper ores to metal on a comparatively large scale was practised simultaneously in ,britain and in ,central ,europe2 first by primitive methods similar to those indicated above1 developing later by successive improvements into the employment of small blast furnaces4 ,by about #agjj1 however1 the methods diverged1 and it is interesting to note that the different styles of working then introduced have persisted1 until recent years1 as the methods typical of these two parts of the world4 ,in ,wales1 where the well-known furnace coal was one of the characteristics of the locality1 as it still remains to-day1 the smelting processes developed along the lines of reverberatory practice1 for which such fuel is eminently suited1 and this resulted in the establishing of the representative ,welsh process4 ,on the other hand1 the enormous forests of ,central ,europe furnished wood suitable for the making of charcoal1 a type of fuel which necessitates close proximity with the furnace charge1 so that in these localities smelting was carried out in the shaft furnace1 which gradually developed into the small blast furnace4 ,at the present time1 the solid fuel suitable for reverberatory practice is only obtainable in very small quantities in ,central ,europe1 and the characteristic method employed there for copper smelting is that in which small blast furnaces are used1 except that charcoal has been largely replaced by coke as the fuel4 ,it is probable that the early ore furnaces of the primitive blast-furnace type in ,britain were worked by ,germans experienced in that class of work1 just as at a later period in the history of the industry1 ,swansea coppermen were to be found in all parts of the world teaching other nations their art4 ,gowland reproduces a letter1 dated ,january1 #aehc1 protesting against the introduction of this foreign labour1 whilst a second letter1 dated ,july1 #aehe1 which is also quoted1 is of particular interest1 as it gives evidence of a remarkable knowledge of the art of smelting1 and1 whilst illustrating an important feature of modern practice1 indicates also the manner in which an astute smelterman was able to work profitably with difficult material so long ago as three and a quarter centuries4 ,the letter is to the following effect3-- 8,,ulricke ,,frosse to ,,robert ,,denham4 #dth ,july1 #aehe4 8,to his loving friend1 ,robert ,denham4 8,friend ,denham1--,i have me heartily commended unto you1 you shall understand it we did lack ore more than #ad days ago1 for we have found out a way to smelt #bd cwts4 of ore every day with one furnace1 the ,lord be thanked1 and if we may have ore enough from your side we may1 with ,god's help1 melt with two furnaces in #dj weeks #efj tons of ore1 having reasonable provision made for it1 desiring you from hence-forward to send such ores as you have with as much speed as maybe1 not caring what ore it is4 ,your ore of ,st4 ,dines is very hard to melt it1 hoping we will overcome it what ,st4 ,ust ores will do1 we long to see it4 8,this ,i rest1 the ,lord send you good success with your mines4 ,and so ,i commit you to ,god4 ,from ,neath1 the #dth of ,july1 #aehe4 8,your friend1 8,,ulricke ,,frosse4 8,when you do send any more ore1 if you can1 send of all sorts1 the better it will melt and with more profit40 ,the sound principle of obtaining1 when possible1 one class of copper ore for the purpose of fluxing off the gangue from ore of another class1 was thus recognised as a profitable feature of practice from comparatively early times4 ,copper mining and smelting in ,staffordshire dates back a considerable time1 certainly prior to #afhf2 the mines were situated at ,ecton1 and the smelter was at ,elleston1 near ,ashbourne1 where small blast furnaces were employed4 ,copper smelting in ,lancashire1 which is nowadays conducted on a comparatively extensive scale1 appears to have commenced in #agbj with ,cornish ores and smaller importations from the ,west ,indian and ,american ,colonies4 ,during the #ahth century1 the chief supply of the world's copper ore came from the ,cornish mines1 which even at that time1 were deep and extensive4 ,it seems1 however1 that for some peculiar reason1 the ,cornishmen were unable to smelt these ores with profit1 nor indeed1 to do more with them than to send the material to ,south ,wales to be treated4 ,there are numerous explanations for their failure1 which have been discussed exhaustively by ,percy4 ,the centre of the copper smelting industry thus came to be located in the ,south ,wales 7,swansea7 district1 where circumstances were very favourable4 ,the study of local conditions is one of great importance for metallurgists1 and since this case affords a good example1 it will be of value to refer briefly to those circumstances which rendered the ,swansea district such an excellent centre for the industry4 ,the extensive collieries in the locality rendered available an abundant supply of suitable fuel at a low price1 and many of the smelters held a financial interest in them4 ,the large coal was profitably used for home consumption or export1 and the small1 which1 though dirty1 still gave the long flame required1 was very suitable for smelting work1 and was reserved for that purpose4 ,further1 ,swansea was an excellent seaport1 situated at a short distance only from ,cornwall1 the chief source of ore1 and was also readily accessible to vessels carrying cupriferous ores and products from ,south ,america1 ,australia1 and other parts of the world4 ,this was a great advantage1 in that the ,swansea copper smelters1 having a large variety of ores at their disposal1 some with basic gangue1 others with siliceous gangue1 were in a position to make up furnace charges which were more or less self-fluxing1 and thus avoided the necessity for purchasing and using barren fluxes4 ,the finished products were also in a most convenient centre for distribution1 at the seaport of ,swansea4 ,at the end of the #ahth century1 ,great ,britain was producing #ge per cent4 of the world's copper1 the ,cornish mines supplying most of the copper ore1 and the ,swansea smelters extracting most of the world's supply of metal4 ,stevens has summarised the position for #agii1 showing that 8from the ,cornish ores #d1ibc tons of refined copper were produced1 and from the ,welsh ores of ,anglesea #b1jjj tons4 ,the great ,mansfeld mine in ,germany produced only #cgb tons in that year1 ,spain's output was insignificant1 and in the ,united ,states only a few tons were made4 ,russia and ,japan probably ranked next to ,great ,britain as producers1 small amounts of ore from ,austria1 ,scandinavia1 and ,italy made up the remainder4 ,thus at the commencement of the #aith century1 the copper resources of the ,united ,states1 ,spain1 ,chili1 ,mexico1 ,australia1 ,tasmania1 ,canada1 and ,south ,africa1 which now supply over #ij per cent4 of the world's metal1 were either undeveloped1 or only yielded a few tons each2 ,great ,britain1 which produced nearly #g1jjj tons of copper at that time1 extracted from its own ore supplies1 a hundred years later1 only #eej tons40 ,it will be remembered that it was in connection with the development of ,cornish copper mining that the use of steam power in engineering was introduced and successfully worked out4 ,on account of the increasing depth and extension of the ,cornwall mines1 the problem of disposing of the underground water became urgent1 and led to the introduction of steam engines for driving the pumps1 the ,newcomen engine being installed on the ,wheal ,fortune ,mine in #agbj4 ,the success of this engine led to increase both in depth and in extent of the workings1 until it became impossible to cope with the pumping requirements by this means4 ,at the right moment ,watt brought out the modern steam engine1 and the first ,watt engine was erected in #aggg at ,chasewater1 in ,cornwall4 ,it was the introduction of these improved methods of pumping which have made possible the successful development of present-day mining4 ,not only has the steam engine thus led to an increase in the supply of copper1 by enabling the opening up of vaster deposits to be undertaken1 but the development of engineering science which it has brought about1 has caused a further consumption of the increasing quantity of copper which it has helped to render available for use4 ,during the first half of the #aith century ,great ,britain retained its position as the chief copper producer of the world1 and the ,swansea smelters possessed advantages such as have been rarely enjoyed by any other body of manufacturers4 ,they were able to impose what conditions they pleased on the producers and sellers of copper ore1 as well as on the consumers of the metal1 and as business men1 were not slow to avail themselves of their opportunities to the greatest possible extent1 strengthening their position by the formation of a combination known as the ,associated ,copper ,smelters of ,swansea1 which controlled the price of the metal from #ahej to #ahfj4 ,percy gives an interesting account of the terms imposed by them under the name of returning charges1 etc41 as well as of the conditions of sampling1 analysis1 and sale1 which were strongly in their favour4 ,during these years of monopoly1 the smelters were1 on the whole1 conservative in tendency from the metallurgical point of view1 and few great developments in either processes or methods were devised3 nevertheless1 they enjoyed great prosperity1 and their business attained such dimensions that ,swansea remains one of the greatest centres of smelting industry in the world4 ,the ,welsh smeltermen had1 moreover1 acquired such proficiency in furnace management1 and such knowledge of the working and control of copper charges1 that their reputation had spread to all quarters of the world4 ,though from #ahdj onward1 the ,british copper mining industry commenced to decline1 still for #bj years longer the ,swansea smelting works prospered more and more as new mines were being opened abroad and thus furnished a constantly increasing supply of rich copper ore1 cheap to purchase and easy to smelt4 ,it was this development of foreign copper resources1 and the unsatisfactory conditions which the producers received at the hands of the smelters1 which was the cause of the eventual displacement of ,swansea from its position as the leading seat of copper manufacture4 ,in #ahcj1 the production of copper ore in ,chili had commenced and developed rapidly1 ,chili soon becoming one of the chief suppliers of ore to the ,welsh smelters1 whose independent attitude led to the first introduction of the copper-smelting industry on any large scale in ,america4 ,owing to the sailing conditions of the time1 the simultaneous coming into port of several ships laden with ore1 instead of their arrival at regular intervals1 enabled purchases to be made by the smelters at a remarkably low figure1 the standard price of the metal being subsequently raised4 ,mine-owners commenced to seek for a remedy1 their ultimate endeavour being to substitute1 for the exportation of their ores1 smelting operations at or near the mines themselves4 ,in #ahdb ,lambert introduced reverberatory furnaces into ,chili1 and so great was his success1 that in a short time they were in use throughout that country4 ,in #aheg he erected the first blast furnace in ,chili1 and the smelting industry thereupon grew so rapidly that1 whilst from #ahef to #ahfe the copper exports from ,chili were in the proportions of ore #ba per cent41 regulus #ch per cent41 and bars #dj per cent41 they subsequently became ore #a per cent41 regulus #c per cent41 and bars #ie per cent4 ,the ultimate effect was a widening of the market for the finished ,chilian product1 so that ,continental purchasers were enabled to obtain their supplies of metal direct1 instead of being obliged to purchase from the ,welsh smelters on the unsatisfactory terms then prevalent4 ,in #ahdb the first large copper mines of ,australia 7,kapunda and later ,burra ,burra7 were discovered1 but developed slowly2 and in #ahdd the first copper mines of the ,lake ,superior district began work--on oxide ore1 not on native metal4 ,in #ahej an enormous development in the ,chilian mines commenced1 half the world's copper being produced from this source2 in #ahei-fj the ,spanish mines at ,st4 ,domingo 7,mason and ,barry7 were re-opened1 as well as the ,portuguese mine1 the ,tharsis4 ,these mines were in reality operated in order to supply the wants of the sulphuric acid industry1 the ore residues being subsequently smelted for copper at ,swansea4 ,in #ahfb1 however1 the ,henderson wet process for copper was introduced1 for which these materials were very suitable1 and the ,spanish and ,portuguese supplies became of considerable importance1 soon afterwards coming under the control of a ,scottish company4 ,the competition from these new and abundant supplies of rich ores from ,chili1 ,spain1 and ,portugal severely injured the production from the ,british mines2 increasing supplies led to a fall in the price1 and one native mine after another shut down1 the ,british supply diminishing with considerable rapidity4 ,in #ahff the great ,calumet and ,hecla mine at ,lake ,superior commenced operations1 and speedily became one of the most important sources of copper in the world2 the ,moonta and ,wallaroo mines in ,australia opened about the same time1 and in #ahgc the ,arizona mines started producing4 ,in #ahgf the enormous ,spanish mines at ,rio ,tinto were re-opened1 and soon rendered available large quantities of ore4 ,later1 the ,tasmanian supplies entered the markets4 ,in #ahhj a remarkable development in copper mining occurred with the discovery of the ,butte camp in ,montana2 this is now the greatest producer in the world4 ,the later extensions of the copper mining industry occurred in ,utah1 ,tennessee1 and ,queensland1 whilst within recent years the most important work on a large scale has been commenced in ,tanganyika1 in ,nevada1 and in ,siberia4 ,the developments in the smelting industry in most of these localities have proceeded1 until the last few years1 on very similar lines4 ,during the first periods following the opening up of mines and works1 ore was shipped to the custom smelters1 most often to ,swansea2 where1 in the early days1 many of those connected with the smelting works had some sort of financial interest in the foreign mines4 ,later1 the ore underwent its first smelting to matte in the mining district itself1 the matte product being then shipped ,east for treatment1 thus saving much of the freight-charge on useless gangue1 as well as smelters' heavy returning charges1 etc4 ,at a later period the smelting operation was carried to a still further stage in the mining district1 crude blister copper only being sent to ,swansea or elsewhere to be refined4 ,gradually1 electrolytic refineries were established somewhat nearer to the mining districts1 and in the natural course of events1 and where local conditions are not prohibitive1 the probability is that the whole cycle of operations from mining to the production of refined market metal will be carried out at the great camps themselves4 ,at present1 however1 this is not generally the case1 since the conditions under which the enormous refineries in the ,eastern ,states of ,new ,york1 ,new ,jersey1 and in ,baltimore1 etc41 operate1 allow of the cheaper production of electrolytic copper at points nearer to the distributing markets4 ,at ,anaconda1 indeed1 the fully-equipped electrolytic plant was shut down1 owing to the commercial conditions such as have just been indicated1 having rendered the refining of the anode copper at the ,eastern refineries more profitable than electrolytic treatment on the spot4 ,the ,chief ,features in the ,development of ,modern ,copper ,smelting ,practice4--,in the early days of copper smelting1 the reduction of the oxidised ores1 which were then chiefly available1 was not a problem of very great difficulty1 although losses in slag were likely to be very high1 and the operation generally wasteful4 ,when1 however1 mines became deeper and sulphide ores had to be smelted1 the problem became rather more complicated4 ,in the first stages of development1 such ores were probably roasted until as much sulphur as possible had been driven off1 leaving practically an oxide charge to be treated by the older reduction methods involving the attendant extravagance in fuel consumption and large losses of copper in the slag4 ,from these crude and wasteful methods the ,welsh process was gradually worked out1 and it will ever rank as one of the finest examples of highly developed smelting practice in the history of metallurgy1 particularly when the times and working conditions are borne in mind4 ,the process having received such full treatment from most of the common text-books1 it is not proposed to review it in detail here1 since1 moreover1 it has been largely superseded by more modern processes4 ,as will be explained later1 copper smelting of sulphide ores is essentially a fractional oxidation--chiefly of iron and sulphur--followed by the slagging or elimination of extraneous constituents of the ore4 ,the ,welsh process embodied a series of roastings and slaggings which1 though most admirably adjusted for a substantial concentration of the copper in each succeeding product1 allowed of the formation of slags in the first stages which carried but comparatively little copper1 on account of the low tenor of the matte2 whilst the slags in the later stages of the process1 containing more copper on account of their association with higher grade matte1 were made in such relatively small quantity that their re-treatment for the recovery of these values did not involve very much loss of efficiency in the furnace operations4 ,later modifications of the process were chiefly devised with the view to reducing the number of operations1 by eliminating the successive roasting stages1 for which purpose oxidised materials1 such as roasted or oxidised ores1 were added to the charge4 ,the ,best-,selecting process1 and the ,nicholl and ,james process are likewise valuable and ingenious modifications of the ,swansea method for special work4 ,in general1 however1 up to #ahhj1 there had taken place but little change in principle from the older methods of smelting4 ,the chief improvements involved a slow change in furnace size1 and progress in several details in practice4 ,the more important of these advances were-- 7a7 ,in ,roasting ,practice4--#ahfe4 ,introduction of the mechanically driven furnace 7the ,brckner cylinder72 not1 however1 adopted for copper smelting till many years afterwards4 ,later--,arrangements for using roaster gases for sulphuric acid manufacture4 7b7 ,in ,reverberatory ,furnace ,smelting4--#ahfa4 ,gas firing introduced1 but with very little success for copper smelting1 even at the present day4 7c7 ,in ,blast-,furnace ,smelting4--,several very important changes were introduced in the construction of furnaces4 #ahfc4 ,elongation of the furnace4 ,rachette in ,germany introduced the elliptical blast furnace4 7,intended first for lead smelting2 rapidly adopted for copper matte smelting47 #ahge4 ,the water-jacketing of blast furnaces4 ,the ,piltz water-jacketed furnace was likewise first employed in lead smelting1 and subsequently introduced into copper smelting practice4 ,the principle had1 indeed1 been utilised in certain branches of iron smelting before this date1 but for non-ferrous work the idea was new4 ,although the method of water-jacketing was recognised as leading to great improvement in the working of the furnace1 its use was at first somewhat restricted1 owing to various practical difficulties1 and the ultimate great success was effected when in ,american practice1 the plan of working the two principles of elongated furnaces and water-jacketing in conjunction1 was adopted4 ,commencing from #ahhj1 and onwards1 however1 when production in the ,far ,west began1 enormous advances have been made1 both in connection with the principles of working as well as in practical operation4 ,these include-- 7#a7 ,enormous increase in the size and capacity of furnaces of both the reverberatory and the blast-furnace type4 7#b7 ,the application of the ,bessemer process to copper mattes4 7#c7 ,the development of the pyritic smelting principle4 7#d7 ,the adoption of electrolytic refining4 7#e7 ,the use of mechanically rabbled roaster furnaces4 7#f7 ,the manufacture of sulphuric acid from blast-furnace gases4 7#g7 ,the blast-roasting and sintering of sulphide fines4 ,with an increased output of ore from the mines1 and with increased consumption1 stimulated by the growth of the electrical industry1 the demand for metal increased so quickly that developments naturally followed with a view to an augmented and rapid production by more efficient and scientific processes2 especially since increased competition and poorer ore supplies necessitated a very decided lowering of the costs of production4 ,to meet the enormous present-day demand for metal with the older methods and furnaces would have been impossible4 ,the greatest stimulus to the adoption of these new or modified processes was the shifting of the chief producing centres from the older and more conservative influences to districts like the then newly awakening ,west1 where1 with ever-increasing--almost limitless--supplies of ore available1 and free from the necessity of considering the capital invested in old plants1 the men in charge of the work1 untrammelled by old smelting customs which might stand in the way of rapid progress1 were in a position to develop their ideas with originality and vigour4 ,there may1 nevertheless1 be recalled the important share which ,british1 and especially ,swansea1 workmen had in this great development of the industry4 ,at many of the greater smelters in these new districts1 ,welsh furnacemen are still to be found1 and large numbers went abroad in former days to take charge of such work1 especially during the critical early stages4 ,the principles underlying these modern improvements were1 in many cases1 first worked out by scientists in ,europe4 ,the ,price and ,cost of ,production of ,copper4--,the price of copper has been influenced to an enormous extent by financial speculation1 so that until recent times it has fluctuated very considerably from year to year1 the curve in fig4 #a relating to ,best ,select copper1 indicating this variation over a considerable period4 ,the price of the other qualities of commercial copper follows this line fairly closely1 electrolytic copper being from #b to #d per ton lower1 and standard copper #c to #f per ton4 ,the average value of the standard refined metal at the present time 7,december1 #aiaa7 is about #ef per ton in ,london1 and about #ab cents per pound in ,new ,york4 ,on three occasions during the past century1 and once at least during the past decade1 the market price of copper has been directly affected by more or less artificial conditions consequent on financial manipulation4 ,the first of these instances was the #ahej-ahfj period1 when the ,welsh smelters held the monopoly of the copper trade1 and were in a position to fix their own price2 the second was during the ,french combination of ,secretan during #ahhg-i1 which1 as a result of mere market speculation1 caused fluctuations of price which amounted on one occasion to no less than #ce per ton within twenty-four hours4 ,the third instance was created by the ,american combine4 ,illustration3 ,fig4 #a4--;,fluctuations in the ,price of ,best ,select ,copper4 ,in #ahii the ,amalgamated ,copper ,company was formed in the ,united ,states4 ,this corporation was established in view of the enormously increasing production of the ,west1 and of the extensive development of electrical industry which involved a greatly increased consumption of copper2 and it was probably designed to control the world's copper industry4 ,prices were raised gradually for some time1 but in #aija the ,trust1 as then constituted1 failed1 owing largely to trade depression in ,europe4 ,heavy losses resulted1 as well as expensive law suits1 and the price of the metal dropped again with great rapidity4 ,trade subsequently revived and expanded1 the consumption of copper increased and appeared to overtake the rate of production1 whilst stocks diminished and the price advanced1 until1 in #aijg1 copper was sold at well over #ajj per ton4 ,the ,american financial panic in the autumn of that year again reduced prices to a comparatively low figure1 and they have1 on the whole1 remained fairly steady since1 though showing a tendency to decrease4 ,production has1 meanwhile1 increased very largely1 and a steady price of #ab to #ac cents per pound yields handsome profits to most of the larger concerns4 ,the present situation in the copper market is such that the enhanced production has again resulted in an accumulation of stocks1 which has occasioned restricted output on the part of many of the principal smelters until briskness of trade development shall call forth increased consumption and more satisfactory prices4 ,the question of price is one involving certain considerations to which attention may be drawn4 ,the present conditions and the comparative steadiness in the copper market have been shown in a recent review to result in part from3-- 7#a7 ,the concentration of the copper industry in a few strong hands1 which1 whilst maintaining healthy competition1 keeps the market free from such outside pressure as would reduce the price too much1 and by restricting unprofitable output1 brings production and consumption into equilibrium1 making for stability4 7#b7 ,the comparative cheapness of money1 which has allowed of the financing for large production1 with the prospect of absorption not being long delayed4 ,at the same time1 some of the richer and more cheaply worked mines of former times are gradually approaching exhaustion--recent instances of this will be readily recalled1 whilst the disadvantages of having to work lower-grade deposits at greater depth have also tended to increase the price of metal4 ,these conditions1 on the other hand1 have been counterbalanced by improvements in the mining and metallurgical processes concerned1 by the opening up of new districts1 and by the economies resulting from amalgamation of interests1 involving closer organisation and enormous outputs of material4 ,apart from finance1 two of the factors most likely to affect the price of the metal considerably are the possible replacement of copper for electrical transmission purposes by conductors of other metals2 and further1 the enormous prospective production in the newer districts1 such as ,utah1 ,nevada1 and ,tanganyika1 in the course of a few years4 ,the cost of production of the metal is so dependent on local and general circumstances as not to admit of analysis in this place4 ,questions of locality1 transport facilities1 proximity to supplies of every kind1 problems of labour1 capitalisation1 bye-products1 and numerous similar considerations have such an important bearing on each individual case as to convey a definite meaning only to the man on the spot4 ,in the same way1 detail costs of each stage of the copper smelting processes are influenced by similar circumstances4 ,broadly speaking1 the average total cost of production and marketing at present may be taken as being somewhere about #aj cents per pound of copper2 in certain specially favoured cases1 #i1 #h1 or even #g cents per pound4 ,the newly opened low-grade 8porphyry0 camps at ,utah and elsewhere1 which have been commenced under an enormous capitalisation1 anticipate a production at a cost of about #f cents per pound when steady and normal running is in progress4 ,a recent analysis gives interesting information with regard to the cost of production estimated at different plants4 ,of the ,american output of about #dhj1jjj tons in #aiji-- ,almost #ce per cent4 was produced at a cost of #gad cents per lb4 7,nevada74 #ah #gih 7,baltic1 ,superior74 #aje #h-i 7,utah1 etc474 #dhc #i-aj 7,boston and ,montana1 ,calumet and ,hecla1 etc474 #ij #aj-aa 7,utah ,consolidated1 ,tennessee1 etc474 #bjj #aa-ab 7,anaconda1 ,arizona1 ,cananea74 #ah #ab-ac #aa #ac-ad #ad #ad-ae 7,tamarack74 #aa #ae-af #aa #af-ag #ja #agji ,copper ,statistics4--,the outstanding features which attract attention in the statistics of copper production will be most readily seen from the curves of fig4 #b4 ,the enormous increase within recent years in the total output of metal1 and the overwhelming proportion produced by the ,united ,states of ,america1 is clearly indicated4 ,the curves also show the practical extinction of the native supply of ,great ,britain and the steady output of ,spain and ,germany4 ,an analysis of the total production for the year #aiaj is given in the following ,table ,i43-- ,,table ,i4--,,the ,,production ,,of ,,copper 7,short ,tons of #b1jjj lbs474 #aiji4 #aiaj4 ,u4 ,s4 ,a41 #edi1aad #edc1abe ,canada1 #bf1iih #bh1hja #aiji4 #aiaj4 ,newfoundland1 #a1edf #a1baj ,north ,america1 ,mexico1 #fc1jhe #fh1hii #fdd1jeh #fde1ibg ,cuba1 #c1cae #c1hib ,argentina1 #fgb #ccf ,bolivia1 #b1bdj #b1hjj ,south ,america1 ,chili1 #dj1jgi #ci1dfc #fj1iaa #fc1aja ,peru1 #ag1ibj #bj1ejb ,spain and ,portugal1 #eh1ddg #ef1chf ,germany1 #be1aej #bg1fge ,russia1 #ai1hhj #bd1ihg ,norway1 #aj1agj #aa1fgf ,hungary1 #e1aeb #e1eej ,europe1 #abg1bhc #ace1gch ,sweden1 #b1bdj #b1bdj ,italy1 #c1jeb #c1fjf ,austria1 #a1hji #b1chf ,turkey1 #hif #fgb ,great ,britain1 #dhg #efj ,japan1 #eb1fdj #ea1ebj ,africa1 #af1gch #ag1jcj ,australasia1 #ch1ebh #de1aec ,total1 #idj1aeh #ieh1dfi ,illustration3 ,fig4 #b4--;,annual ,production of ,copper4 ,in ,table ,,ii4 is indicated the distribution of the ,american production among the various ,states4 ,,table ,,ii4--,,north ,,american ,,production ,,of ,,copper 7in ,short ,tons of #b1jjj lbs474 #aiji4 #aiaj4 ,alaska1 #b1jbh #b1ejd ,arizona1 #adf1jba #adi1hjc ,california1 #bf1fgi #bb1hig ,colorado1 #e1bdd #e1jfc ,idaho1 #c1hhe #c1ajh ,michigan1 #aac1fbd #aaj1gjj ,montana1 #aef1iah #adc1aba ,nevada1 #be1iag #ca1idd 7about #f1jjj tons in #aijh7 ,new ,mexico1 #b1efg #a1haf ,utah1 #ej1bai #fb1eba 7about #ce1jjj tons in #aijh7 ,wyoming1 #dd #ij ,south and ,east1 #aa1dji #i1jih ,other ,states1 #a1igc #dfc ------- ---------- ,totals1 #edf1ech #edc1abe ,there will be noticed a decline in the production of the ,united ,states during the year #aiaj1 resulting from the present movement to restrict output whilst the large accumulated stocks of metal are being absorbed4 ,the movement is probably more or less temporary1 and is being largely directed by ,american financiers who are endeavouring to bring about an international agreement on the subject4 ,regarding the ,american output1 the marked movement for curtailment in ,montana has reduced the output of that ,state to such an extent1 that the position it gained in #aiji1 of being the greatest producing ,state once more reverts to ,arizona4 ,the increases from ,nevada and ,utah1 in which developments on a large scale are commencing1 may be noted4 ,references4 ,percy1 ,john1 8,metallurgy 7,copper740 ,gowland1 ,william1 ,presidential ,address1 ,trans4 ,inst4 ,mining and ,metallurgy1 vol4 xvi41 #aijf-g1 pp4 #bfe-bia4 ,stevens1 ,h4 ,j41 8,the ,copper ,handbook40 ,brown1 ,n41 and ,turnbull1 ,c4 ,c41 8,a ,century of ,copper40 ,engineering and ,mining ,journal1 8,copper ,production40 ,may #fth1 #aiaj1 p4 #hia4 ,mineral ,statistics of the ,united ,kingdom4 ,mineral ,industry4 ,,lecture ,,ii4 ,the ,uses of ,copper3 as ,metal and as ,alloy -- ,the ,physical ,properties of ,copper -- ,effects of ,impurities -- ,mechanical ,properties -- ,chemical ,properties4 ,the ,uses of ,copper4--,generally speaking1 the industrial applications of copper involve its employment in two forms3-- 7#a7 ,as metal4 7#b7 ,as a constituent of alloys4 ,the more limited use in the form of copper salts is of chemical rather than of metallurgical interest4 ,copper in the metallic form is employed for three classes of work3-- 7a7 ,for electrical purposes4 7b7 ,for engineering purposes4 7c7 ,general industrial uses4 7a7 ,electrical ,uses4--,of late years the marked growth in the consumption of copper has arisen very largely from its usefulness as a conductor of electricity2 the increased demand for the metal with the development of electrical enterprise being a well-marked feature in industrial progress4 ,it is estimated that from #fj to #gj per cent4 of all the copper produced is utilised for this purpose1 and metal is specially prepared and sold under the designation of 8high-conductivity copper40 ,the demand has1 to a large extent1 increased irrespective of price up to recent years1 owing to the necessity of employing copper for such purposes1 though the natural economic factor that an enhanced price of the metal tends to some discouragement of expansion and of fresh electrical enterprise1 has exerted considerable effect in checking consumption4 ,it is merely necessary to enumerate some few of the present aspects of electrical industry in order to realise the enormous absorption of copper in this connection1 as1 for instance1 electrical traction1 lighting1 and power1 the telegraph1 and the telephone4 ,with reference to the use of the metal for this work1 it is important that certain mechanical as well as electrical requirements should be fulfilled1 for in many branches1 considerable strength of the material is also requisite4 ,the demand of the electrical engineer is that as a conductor1 the copper shall offer a minimum of resistance to the passage of the current1 and for this requirement the metal must be in a condition of very great purity4 ,with but few exceptions1 this necessitates the purification of the copper by electro-deposition4 ,electro-deposited metal as produced at the refineries is1 however1 not immediately suitable for drawing into wire1 owing to the weakness and porosity inherent in the material prepared by this method4 ,it must1 therefore1 be melted1 brought to pitch1 cast into bars1 and these bars transformed into wire1 which operations require to be conducted with much care in order to keep the metal in as pure a condition as possible for its work4 ,it may be noted that within recent years1 several processes1 notably those of ,cowper-,coles and ,elmore1 have been put into operation for the direct manufacture for electrical purposes1 of electrolytic-copper wire of the requisite strength4 ,the mechanical qualities demanded of the metal for such purposes as telegraph work may be indicated by the two specifications of wire for the ,british ,post ,office1 which are appended3-- ,a4 ,post ,office ,specification4 ,weight1 #aej lbs4 per mile4 ,minimum diameter1 #ie4 ,maximum diameter1 #ih4a ,minimum breaking strain1 #dij lbs4 ,minimum number of twists1 #be in #c inches4 ,wraps required1 #f times round wire of its own diameter1 unwrapped1 and again wrapped without breaking4 ,maximum resistance per mile at #fj ,f41 #eheg 4 ,b4 ,post ,office ,specification4 ,weight1 #ejj lbs4 per mile4 ,minimum diameter1 #ace4 ,maximum diameter1 #ach4 ,minimum breaking strain1 #iej lbs4 ,minimum number of twists1 #cj in #f inches4 ,wraps required1 #f times round wire of its own diameter1 unwrapped1 and again wrapped without breaking4 ,maximum resistance per mile at #fj ,f41 #bibh 4 ,the following figures afford some indication of the increasing demand for copper in two branches only of electrical industry3-- #aijb4 #aijg4 ,mileage of wire for telegraph purposes1 #ci #ec telephone purposes1 #aji #bhb 7in million of miles7 7b7 ,engineering ,uses4--,metallic copper finds application in marine shipbuilding and engine work1 as well as in railway and locomotive work1 where the metal is particularly employed for steam pipes1 and for fire-box plates and stays1 sometimes also for boiler tubes1 on account of its high conductivity for heat1 combined with toughness4 ,the questions of suitable composition1 and the other requirements of the metal intended for these purposes1 has been a subject for discussion by some of the leading marine and locomotive engineers4 ,useful information on the subject will be found in the reports of some of these discussions at the ,institution of ,mechanical ,engineers4 ,the following tests are required for copper plate 7best quality7 intended for locomotive fire-boxes on the ,lancashire and ,yorkshire ,railway1 taken from standard specifications given by their ,chief ,mechanical ,engineer at the ,institute of ,metals3-- ,bending ,test4--,pieces of the plate shall be tested both cold and at a red heat by being doubled over on themselves-- that is1 bent through an angle of #ahj--without showing either crack or flaw on the outside of the bend4 ,flanging4--,plates must not show any defects in flanging4 ,tensile ,test4--,ultimate breaking load1 #ad tons per square inch2 ,elongation1 #ce per cent4 in #h inches4 ,analytical ,test4--,to be made at contractor's expense4 ,the copper upon analysis to give the following results3--,arsenic1 not less than #jce per cent4 nor more than #jee per cent42 other foreign elements1 exclusive of combined oxygen1 not to exceed #jbe per cent4 ,clauses are also inserted as to stamping1 inspection1 and the giving of testing facilities4 ,typical analysis of such plates show-- ,copper1 #iicj per cent4 ,arsenic1 #jdc to #jea per cent4 ,oxygen1 #ja per cent4 ,impurities1 chiefly antimony1 lead1 iron1 nickel1 tin1 and sulphur1 not exceeding #jbe per cent4 ,the average test on a number of plates gave-- ,tensile strength1 #adff tons per square inch4 ,elongation on #h inches1 #dccf per cent4 of original length4 ,contraction of area1 #dei per cent4 ,close bend test1 ,double4 ,the effect of temperature and the influence of impurities on the mechanical properties of the metal intended for engineering purposes are of very great importance1 and much attention has been devoted to researches in this subject1 particularly by ,milton and ,le ,chatelier1 whose published experience gives important information of much practical value4 ,the main conclusions arrived at from practice have had reference to the general effects of impurities in hardening the metal1 and the general tendency of heat to soften it and to increase the ductility4 ,the diverse effects of different impurities on strength and ductility will be reviewed in detail at a later stage4 7c7 ,general ,industrial ,uses4--,copper as metal is also employed to a considerable extent in certain important industries1 as in textile manufacture1 where it is used for the rollers in calico-printing2 and it is in general industrial use in the form of copper heaters1 vats1 coils1 pans1 and the like1 and occasionally also for roofing and sheathing4 ,uses of ,copper ,alloys4--,between #bj and #cj per cent4 of the copper produced is employed in the form of alloys4 ,the more important of these are3-- ,brasses2 alloys of copper and zinc4 ,bronzes2 chiefly alloys of copper and tin4 ,coinage ,alloys2 of gold and silver with copper4 ,german ,silver2 alloys of copper1 nickel1 and zinc4 ,special ,bronzes2 alloys of copper with such metals as aluminium and manganese4 ,it is further not unlikely that several classes of ternary alloys1 at present still under investigation1 may have important industrial application in the future4 ,among such alloys may be mentioned the copper-aluminium series alloyed with other metals1 ,monel metal and the ,monel steel series1 etc4 ,of the above alloys1 the brasses are by far the most widely used4 ,it may be recalled that the advantages possessed by alloys of copper and zinc are in large measure due to their increased strength and hardness2 to the fact that they are more fusible1 and more fluid when melted1 and so give good castings2 that they are characterised by a good colour and high lustre1 as well as by the factor of cheapness resulting from the addition of a less costly metal--zinc--in their manufacture4 ,the uses of the copper alloys may also be arranged in two classes--7a7 engineering uses1 and 7b7 general uses4 ,of the brasses1 those containing upwards of #gj per cent4 of copper may be rolled cold1 whilst the alloys with less than #gj per cent4 are hot-rolled4 ,in the engineering industry large quantities of #gj_/cj brass are utilised in the form of condenser tubes1 whilst for the multifarious requirements of general engineering work1 very considerable amounts of brass of lower tenor are employed in the forms of taps1 pipes1 fittings1 etc4 ,muntz metal1 the #fj_/dj brass1 finds extended application for the sheathing of ships1 whilst the employment of brass and of the other alloys for all manner of articles of general utility is a matter of common knowledge4 ,the close connection between properties1 constitution1 and the equilibrium diagram of these various classes of alloys has become manifest to a marked degree within recent years1 and the effects of thermal treatment partly in modifying their constitution1 and thereby the properties1 and also in controlling the condition and distribution of the constituents1 are at the present time having an important bearing on the manipulation of these alloys in the industries manufacturing them and adapting them for their various uses4 ,the study and application of these equilibrium diagrams are highly important to those who have to deal with these alloys on an industrial scale4 ,illustration3 ,fig4 #c4--;,equilibrium ,diagram1 ,cu-,zn ,series4 ,the ,properties of ,copper4--,the properties of the metal which render it of such service in the arts and industries are mainly its high electrical conductivity1 its great ductility1 malleability1 and toughness1 which enable it to be readily worked up into the different forms in which it is employed1 its high thermal conductivity1 and its resistance to the various agencies which lead to corrosion4 ,these are consequently the properties to which close study is directed4 ,of perhaps still greater importance is a knowledge of the influence exerted upon these properties by the circumstances which usually attend working practice2 such as1 for example1 the various common impurities1 and the variations of temperature1 as well as the previous mechanical and thermal treatment4 ,these can only be indicated in general terms here1 references to authorities on the different branches being given later4 ,,table ,,iii4--,,influence ,,of ,,impurities ,,on ,,the ,,electrical ,,conductivity4 ,addicks4 ,johnson4 ,impurity4,conductivity4,impurity4,condu ctivity4 ,per cent4 ,per cent4 ,pure copper1 44 #aja 44 #aja ,copper with-- ,aluminium1 #jjjf #ihf #jja #iig #jaji #ffh #jjb #ihh #jgci #dce 44 44 ,antimony1 #jjjg #iif 44 44 #jjbb #igb 44 44 #jjdg #ied #jje #ifi ,arsenic1 #jjjd #iif 44 44 #jjjg #ifh 44 44 #jjac #icb #jjd #ibd #jadj #fbc #jjf #hbj ,bismuth1 #jjbh #iif #jja #ieg #jjde #iic 44 44 ,cadmium1 #jjfb #iie 44 44 #jaac #iia 44 44 #jdbg #ifa 44 44 ,cobalt1 44 44 #jje #ibj ,gold1 #jjhi #ihi #jje #iig #jadi #ihd 44 44 #jcag #ifd 44 44 ,iron1 #jjdb #ifh 44 44 #jjdf #ibi 44 44 #jjfh #hif #jji #ihh ,lead1 #jjhc #iia 44 44 #jjeb #ihg #jjf #ajjf #jcdg #ihc 44 44 ,manganese1 44 44 #jjb #ihh ,nickel1 44 44 #jje #iad ,oxygen1 #jjbj #ajjg 44 44 #jjej #ajad 44 44 #jajj #ajje #jaj #iih ,phosphorus1 #jjh #ebc #jjjd #ihe ,platinum1 44 44 #jjb #icf ,silicon1 #jjjg #iid #jjjd #iig #jjdb #iij #jja #ihd ,silver1 #jjjc #ajje 44 44 #jacg #ajjj #jje #iih #jcdj #ihc 44 44 ,sulphur1 #jjec #ajjj #jja #ihe #jace #iij 44 44 #jbcf #ihi 44 44 ,tellurium1 #jjfe #ajjd 44 44 #jaha #ajjb 44 44 #jdje #ihg 44 44 ,tin1 #jjeb #igf #jje #ajje #jjig #ibg 44 44 #jbie #gih 44 44 ,zinc1 #jjdh #ihc #jjb #ihe #jjie #ifc 44 44 ,,physical ,,properties4--,the colour of copper is familiar1 being a fine salmon pink4 ,the appearance of the fractured surface is a useful guide in several respects as to the condition of the metal1 and in the process of manufacture the refiner relies upon this appearance as an important criterion of the progress of the refining operation4 ,copper containing an excess of oxygen1 for example1 has a purplish-red colour and a coarse brick-like fracture2 this is known as 8dry copper10 and the metal is brittle and commercially useless when in that form4 ,the ingot of dry copper is also characterised by a depression running along the surface4 ,tough copper 78tough-pitch07 the mechanically useful variety resulting from the furnace-refining operation1 possesses a bright salmon-coloured fracture1 finely granular to silky in appearance1 whilst 8overpoled copper10 also brittle and industrially valueless whilst in that condition1 has a very light salmon-coloured fracture1 and is more coarsely fibrous4 ,the melting point of copper is #a1jhc ,c41 and is slightly lowered by the small quantities of impurity usually present in commercial metal4 ,molten copper is of a pale apple-green colour4 ,the boiling point under ordinary conditions is about #b1cjj ,c4 7#a1gjj ,c4 in vacuo74 ,the electrical conductivity is of much importance4 ,copper ranks second only to silver as a conductor1 the relative conductivity of the best copper being about #ih compared with silver as #ajj4 ,the resistance of #ab inches of pure copper wire1 #jjja inch in diameter1 is #ifab ohms4 ,the conductivity of the metal is decreased by mechanical working1 and it follows the general straight-line law connecting conductivity and temperature4 ,the effect of even small quantities of impurity on this property is very marked1 so much so that only the purest varieties are suitable for electrical work1 and for this reason electrolytic refining is often a necessary operation in the manufacture of copper intended for this purpose4 ,table ,,iii4 on preceding page1 summarises the results of the work of ,addicks and ,johnson1 and indicates the effects of small amounts of different impurities on the conductivity of the metal4 ,the notoriously destructive effect of arsenic on the conductivity is very apparent4 ,the influence of most of the common impurities is of a similar nature1 and detailed investigations indicate that the effect is more or less progressive as the quantity increases--within the limits usually present in commercial metal4 ,the results of ,hiorns and ,lamb's experiments with reference to arsenic and antimony are indicated in ,fig4 #d4 ,the specific gravity of copper naturally varies according to its condition and composition4 ,when pure and in the worked state1 its density is #hie2 cast metal1 more open and inclined to porosity1 has a density of about #hb to #hf1 depending on the purity1 rate of cooling1 etc4 ,impurities lower the specific gravity4 ,the conductivity for heat of the metal is high1 being #hih compared with gold as #a1jjj1 and as a conductor it is two and a-half times more efficient than iron4 ,it is this property1 combined with its toughness and resistance to corrosion1 etc41 which largely determines its employment for heaters1 steam-coils1 and the like4 ,illustration3 ,fig4 #d4--;,influence of ,arsenic and ,antimony on the ,electrical ,conductivity of ,copper4 ,power of ,dissolving ,gases4--,when molten1 especially under reducing conditions1 the metal possesses the property1 common to many others1 of absorbing gases such as carbon monoxide1 hydrogen1 hydrocarbons1 sulphur dioxide1 etc41 which are moreover1 to a large extent insoluble in the solid material1 and are1 therefore1 often liberated at or about the moment of solidification2 though some may remain dissolved4 ,this action is one of the causes of the difficulty which is experienced in making sound castings of the metal1 particularly since the gases mentioned are present in quantity during the poling and refining operations4 ,the presence of certain materials in the copper1 as in the case of steel1 appears to reduce the dissolving power of the liquid metal for these gases1 or possibly to increase their solubility when the copper is solidifying1 and in this way tends to minimise their injurious effects4 ,it would seem that one of the functions of the cuprous oxide1 which is purposely introduced into the metal when 8bringing it up to pitch10 is to exert this action4 ,the ridge in the ingot of overpoled copper is1 to some extent1 accounted for as being due to the effects of the evolved gases1 and this appearance indicates the absence of the requisite quantity of cuprous oxide necessary to counteract the effect4 ,copper is also supposed to be capable of holding certain quantities of gas in solution after it has become solid1 and the resulting metal is more brittle and often commercially useless4 ,several of the characteristics of overpoled copper probably arise from this cause also4 ,impurities#b in ,copper4--,in view of the marked influence of impurities on the properties of metallic copper1 it may be advisable in this place briefly to review the results of recent scientific work as to the condition in which they exist in the metal1 thus offering some clearer indication of the manner in which they affect the mechanical and other properties4 ,the common impurities in ordinary commercial metal may be oxygen1 arsenic1 antimony1 bismuth1 lead1 and to smaller extents1 iron1 sulphur1 tellurium1 and selenium4 ,a factor of much importance is that the effect of two or more of the common constituents when present together1 may be of even greater moment than that of each one separately1 and in this connection ,hampe's classical work should be consulted4 ,the investigation of the joint effects of impurities becomes so complex that systematic study progresses but slowly4 ,metallographic work is1 however1 revealing much evidence1 and the researches in progress at present at several laboratories will1 when published1 afford greatly increased knowledge on the subject4 ,recent papers by ,f4 ,johnson give valuable detailed information 7see ,references1 p4 #cd74 ,the importance of oxygen in this connection is particularly marked3 its effects are profound1 since in addition to its own specific influence as oxide1 it also brings about chemical changes in some of the other constituents1 thus leading to the formation of entirely new compounds possessing quite different properties4 ,the beneficial influence of certain definite proportions of oxygen in addition to the other constituents of commercial copper is well known in practice1 and has been systematically studied by ,hampe1 and later by several other workers with more delicate means of investigation at their disposal4 ,oxygen in ,copper4--,molten copper has the power of dissolving its oxide1 ,cu#b,o4 ,when the melted metal is exposed to oxygen1 this oxide is produced and passes into solution in the liquid1 yielding a series of binary alloys1 of which the oxide acts as the second constituent4 ,the equilibrium diagram of the series1 as worked out by ,heyn#c 7see ,fig4 #e71 affords a good indication of these relationships1 and throws light on several features connected with the presence of oxygen in copper4 ,illustration3 ,fig4 #e4--,relations of ,copper and ,oxygen4 ,it will be observed that when molten oxygenated metal containing less than about #jch per cent4 of oxygen solidifies1 copper crystallises out first1 whilst later1 in between the copper crystals1 there solidifies a eutectic of copper and cuprous oxide4 ,this eutectic contains about #cde per cent4 of cuprous oxide1 equivalent to #jch per cent4 of oxygen2 it melts at a temperature about #ah ,c4 below that of the pure metal4 ,the presence of this material1 which is of a blue colour when viewed under the microscope1 constituting slightly more fusible1 tough1 non-conducting areas between the copper crystals1 accounts for many of the well-known effects of oxygen in metallic copper4 ,when oxygen is present in quantities above the eutectic proportion1 the first constituent to solidify from the molten over-oxygenated copper is brittle copper oxide1 and the presence of such brittle material disseminated through the metal explains why 8dry copper0 cannot be worked4 ,the effects of comparatively small quantities of oxygen are greatly increased on account of the fact that one part of oxygen1 when present as cuprous oxide1 yields a constituent in almost nine times as great a proportion by weight alone1 since ,cu#b,o 3 ,o 33 #adb 3 #af or #i 3 #a2 whilst oxygen existing as oxide-eutectic is represented in the ratio of nearly #cj 3 #a4 ,the presence of excess of copper oxide in the metal is particularly dangerous when copper is to undergo annealing in a reducing atmosphere1 since the reducing gases acting upon the oxides at the crystal boundaries destroy them1 thus tending to produce that rottenness in the material which is so often encountered under such circumstances4 ,the great value and importance of oxygen in copper lies in its property of bringing the metal up to pitch as indicated above4 ,the effect of carbon on oxygenated copper was the subject of much enquiry in early years4 ,it was thought at one time that the influence of carbon per se in the copper was responsible for the beneficial effects resulting from the melting of brittle 8dry0 copper with carbon1 but the work of ,percy1 since confirmed1 showed that its sole action is in the reduction of the injurious excess of oxide4 ,in addition to the specific influences of oxygen as just recorded1 and to its important physical effects with regard to the solubility of gases1 etc41 oxygen in copper performs other valuable functions1 by forming with reduced impurities which are exceedingly dangerous1 oxygenated compounds more infusible and more insoluble2 and this has the effect of segregating or distributing such injurious impurities into forms and positions much less harmful4 ,illustration3 a b ,fig4 #f4--,microstructure of ,copper containing ,oxygen 7,heyn74 a4 ,hypo-eutectic4 b4 ,hyper-eutectic4 ,oxygen #jac per cent4 #aaf per cent4 ,cu#b,o4 ,oxygen #jec per cent4 #dg per cent4 ,cu#b,o4 ,illustration3 ,fig4 #g4--,relations of ,copper and ,arsenic4 ,arsenic in ,copper4--,when arsenic and copper are melted together chemical combination occurs1 and a series of arsenides is produced2 the system1 which has been investigated by ,friedrich 7from whose work the following diagram has been constructed71 ,hiorns1 ,bengough ,hill1 and others1 being one of considerable complexity4 ,with proportions of arsenic such as are usually present in commercial coppers1 the compound produced is probably ,cu#c;,as 7#bhc per cent4 of arsenic71 which passes into solution in the excess of metal1 and on solidification the copper retains this arsenide in solid solution4 ,as in the case of all such solid solutions1 the solidification takes place over a range of temperature represented between the liquidus and solidus curves2 the purer metal crystallising out first1 followed gradually by crystals of copper which become progressively richer and richer in arsenic 7still in solid solution74 ,in the case in question1 diffusion of the arsenic throughout the crystalline mass proceeds but slowly1 and as a result1 the metal1 as usually obtained in the cast state1 shows fringes of such arsenic-rich copper4 ,by annealing1 diffusion is greatly assisted1 and the material gradually becomes homogeneous1 as is seen on microscopic examination4 ,there appears further to be some decrease of this solubility with fall of temperature when the arsenic is high1 leading sometimes to a separation of the arsenide itself at the crystal boundaries4 ,antimony appears to form an analogous compound1 ,cu#c,sb1 also capable of passing into solid solution in the copper1 but to a rather smaller extent than the corresponding arsenide4 ,the fringes are therefore more pronounced1 and the decrease of the solubility on further cooling is also more marked4 ,bismuth4--,the influence of even minute quantities of bismuth on copper is notorious4 ,bismuth appears to be soluble in liquid copper1 but not in the solid metal4 ,in consequence1 when copper containing bismuth solidifies1 the copper crystals separate first1 whilst the liquid bismuth still remains between them1 until the metal reaches a temperature of about #bfh ,c4--the melting point of bismuth--when it too solidifies in situ4 ,the presence of such envelopes of very brittle1 fusible1 and limpid bismuth material explains much of the harmful effect of this impurity4 ,these envelopes are found to consist almost entirely of practically pure bismuth4 ,oxygen converts the bismuth into a more compactly crystalline oxide1 much less fusible and harmful4 ,arsenical copper tends to the scattering of the bismuth globules among the fringes which are formed during the gradual process of solidification over the range of temperature already indicated1 and thus renders this impurity to some extent less dangerous4 ,lead behaves in apparently much the same way as bismuth1 and the effects produced upon it by the presence of oxygen and arsenic are probably similar4 ,selenium and ,tellurium probably exist in the form of selenides and tellurides1 which are characterised by marked brittleness and fusibility4 ,mechanical ,properties of ,copper4--,the mechanical properties of commercial copper are influenced to a vital degree by the conditions associated with working practice1 such as composition1 previous mechanical and thermal treatment1 temperature of working1 etc4 ,as has been already indicated1 it is the possession by the copper of certain mechanical qualifications which leads to its employment by engineers1 and it is1 therefore1 necessary to consider the influence of the above conditions1 when reviewing the mechanical properties of the metal4 ,much of the copper employed for general engineering work 7apart from electrical and alloying purposes7 is of the quality designated as 8tough-pitch0 copper4 ,this tough copper generally contains certain impurities which render the metal exceedingly useful for mechanical service1 and their presence is1 indeed1 almost essential in copper intended for such purposes4 ,at the same time1 such elements would render it absolutely unfit for the other uses just specified1 where purity is practically the first necessity4 ,the standard works and the papers indicated in the appended list of references should be consulted for details concerning the effect of each circumstance on the several mechanical properties2 certain general considerations must1 however1 be noted here4 ,not only should the composition of the metal be carefully considered1 but attention must be directed to the actual condition and distribution of each constituent4 ,owing largely to the difficulties of determining the oxygen contents in copper1 and to a want of definite knowledge as to the condition1 amount1 and effects of the dissolved gases in the metal1 the information at present available is not sufficiently concise to allow of a systematised statement being made as to the direct influence of the constituents on the mechanical properties4 ,this is more especially the case since the other attendant circumstances of working practice may react through these to a considerable extent4 ,many of the more general results have1 however1 long been known to engineers from practical working1 and these have been placed on record from time to time4 ,the malleability and ductility of copper are considerable4 ,cold rolling and hammering causes a reduction in this respect1 and the metal is hardened1 but the properties are restored by annealing4 ,the annealing effect commences at about #cjj ,c41 but proceeds more effectively at higher temperatures1 the factors of annealing temperature and duration necessary for annealing being inversely connected4 ,the impurities which influence these properties most adversely are bismuth and tellurium4 ,the effect of other constituents1 oxygen per se1 sulphur1 and iron1 in the quantities usually present in commercial copper1 is very small4 ,arsenic and antimony up to #jd or #je per cent4 have no deleterious effect on the malleability and ductility of copper of the correct pitch1 and may even improve the metal when tested in the cold2 the hot malleability is1 however1 somewhat decreased4 ,the presence of impurities raises the temperature required to bring about the full effects of annealing after the metal has been hardened by mechanical work4 ,this action is probably explained by the interference of the impurities upon the molecular freedom of the metal1 which controls the mechanism of annealing4 ,the conditions1 whether reducing or oxidising1 during annealing1 may exert an important influence on the results4 ,hardness4--,pure copper is a comparatively soft metal4 ,it is hardened by mechanical work--the hardness of rolled copper1 determined by the ,brinell ,test1 being #gd compared with mild steel as #ajj--;and by the presence of even small quantities of impurities1 tin possessing a particularly marked effect in this connection4 ,the worked metal is softened on annealing4 ,tensile ,strength and ,elongation4--,the strength of copper1 being a property of such practical importance1 has been the subject of much extended investigation4 ,the work has1 however1 been conducted under such a great variety of conditions1 many of which have been left unrecorded1 that co-ordination of the results is barely possible1 and does not allow of establishing on a definite basis the effect of different influences on this property of the metal4 ,later work1 some already published1 some still in progress1 should eventually allow of more general standardisation than is at present possible4 ,the tensile strength of pure cast copper is #h to #i tons per square inch4 ,mechanical work causes an increase in the value up to #ad1 or even #af tons1 cold work exerting a still more marked influence2 whilst #cc tons and more per square inch has been recorded with cold-drawn fine wire4 ,the elongation varies according to the mechanical work which the metal has undergone2 the amount ranges from #ce to #dj per cent4 and upwards1 measured on a #c-;inch length4 ,tensile strength is reduced on annealing1 but never to so low a degree as that of the cast material1 the usual figure being #ab to #ad tons per square inch4 ,the effect of temperature in reducing tensile strength1 especially when impurities are present1 is important from the industrial point of view4 ,the reduction in strength caused by annealing appears to be considerably smaller in the presence of arsenic and antimony4 ,arsenic increases the tensile strength of copper when the metal is of the correct pitch1 generally to well over #ae or #af tons1 in the presence of the proportions usually found4 ,antimony has a similar effect4 ,some workers state that1 within certain limits1 the strengthening effect of this element is even more pronounced4 ,excess of antimony exerts1 however1 a much more adverse influence than does excess of arsenic4 ,the elongation is increased by the presence of moderate quantities of arsenic4 ,oxygen per se1 when present in moderate quantity in copper1 has but little effect on the tenacity4 ,bismuth1 tellurium1 sulphur1 and lead are the impurities which lower the strength1 even when present in minute quantities1 and especially on heating4 ,bismuth in the proportion of #jjje per cent4 lowers the malleability and ductility considerably1 and recent reports state that #jjb per cent4 bismuth renders copper cold short1 that #jje per cent4 makes it red short1 and that #jjje per cent4 is the limit for electrolytic copper which is to be rolled4 ,the deleterious effects of bismuth are1 as already explained1 to some extent masked by the presence of arsenic and by oxygen4 ,the strength is increased by the presence of nickel1 tin1 and zinc in the proportions usually present in the commercial metal2 these are1 however1 generally small4 ,from the foregoing review1 indications will be afforded of the reasons for the choice by engineers of 8tough-pitch0 copper for much of their work1 and the explanation for the #jc to #je per cent4 arsenic often particularly specified for4 ,the frequent use of arsenical coppers for such purposes as fire-box plates will also be understood1 since the arsenic not only improves the mechanical properties of the metal1 but ensures the retention of rigidity and strength at the high working temperatures required1 to a greater degree than would have been the case had pure copper been employed4 ,the effect of the above factors on the elastic limit of copper1 is also very marked and of much importance1 the influence being closely analogous to that produced on the other mechanical properties4 ,chemical ,properties4--,the atomic weight of copper is #fceg4 ,the metal is unchanged in dry air at ordinary temperatures2 in the presence of moisture and of carbon dioxide a green coating of basic carbonate is produced4 ,when heated in air1 a black scale1 consisting of cuprous oxide1 ,cu#b,o1 is obtained1 which is readily detached by quenching and hammering4 ,water at ordinary temperatures is without effect upon copper2 concentrated sulphuric and nitric acids have little action upon it in the cold1 but attack it on heating4 ,the best solvent for the metal is dilute nitric acid1 which dissolves it very readily4 ,copper is liable to corrosion when subjected1 whilst hot1 to the action of chlorine or hydrochloric acid gas2 this action has provided an explanation of the corrosion of copper boiler tubes where the coal employed had been exposed to sea water4 ,copper is deposited from solution as a dull red1 spongy mass1 by iron1 zinc1 or aluminium1 but it is more electro-positive than gold or silver1 and readily precipitates these metals from solutions of their salts1 these effects being extensively made use of in practice4 ,the metal possesses a powerful affinity for sulphur1 and this property has very important applications in the smelting processes4 ,copper readily alloys with gold1 silver1 tin1 zinc1 and nickel1 but not with lead or iron4 ,references4 ,composition and ,properties of ,metal for ,railway and ,locomotive ,work 7p4 #bj74 ,proc4 ,inst4 ,mech4 ,eng41 #ahic2 ,dean1 p4 #aci2 ,blount1 p4 #afd2 ,watson1 p4 #afh2 ,gowland1 p4 #agf2 ,aspinall1 p4 #aic2 ,tomlinson1 p4 #ahb4 ,webb1 ,f4 ,w41 8,locomotive ,fire-box ,stays40 ,proc4 ,inst4 ,c4,e41 #aijb4 ,milton1 ,j4 ,t41 8,the ,treatment of ,copper for ,steam ,pipes40 ,inst4 ,marine ,eng41 #aijh-i4 ,hughes1 ,g41 8,non-ferrous ,metals in ,railway ,work40 ,j4 ,inst4 ,metals1 ,sept4 #aiaa4 ,law1 ,e4 ,f1 8,alloys40 ,influence of ,impurities on the ,electrical ,conductivity of ,copper 7p4 #bd74 ,lawrence ,addicks1 ,trans4 ,amer4 ,inst4 ,elect4 ,eng41 #aijc1 vol4 xxii41 pp4 #fie-gjb2 ,electro-,chemical ,industry1 #aijb-c1 pp4 #ehj-ehc2 ,trans4 ,amer4 ,inst4 ,min4 ,eng41 #aijf1 vol4 xxxvi41 p4 #ah4 ,walker1 ,a4 ,l41 ,mineral ,industry1 #ahih1 vol4 vii41 p4 #bdh4 ,t4 ,johnson1 8,some ,features in the ,metallurgy of ,copper40 ,proc4 ,b'ham4 ,met4 ,soc41 #aijf4 ,hiorns and ,lamb1 8,influence of ,arsenic and ,antimony on ,copper40 ,journ4 ,soc4 ,chem4 ,ind41 ,may1 #aiji4 ,condition and ,influence of ,impurities on the ,mechanical ,properties of ,copper 7p4 #cb74 ,zeitschrift fr ,berg4 ,hutten and ,sal4 ,wesen1 ,hampe #ahgc1 xxi41 #bah2 #ahgf1 xxiv41 #bf ,chemiker ,zeitung1 #ahib1 ,no4 #db1 p4 #af4 ,heyn1 ,e41 ,reports1 ,royal ,tech4 ,testing ,institute4 8,copper and ,oxygen40 ,charlottenburg1 #aijj1 p4 #cae4 ,metallographist1 vol4 vi41 #aijb1 p4 #dh4 ,arnold1 ,engineering1 vol4 lxi41 p4 #agf4 ,feb4 #g1 #ahif4 ,roberts-,austen1 ,second ,report1 ,alloys1 ,research ,committee4 ,proc4 ,inst4 ,mech4 ,eng41 ,april1 #ahic1 p4 #aad4 ,rudeloff1 ,mittheil4 ,knig4 ,tech4 ,versuchs4 ,anstalt41 #ahid1 ii4 7b71 pp4 #bib-ccj2 #ahih4 #af;a1 pp4 #aga-bai4 ,lawrie1 ,bull4 ,amer4 ,inst4 ,min4 ,eng41 #aiji1 pp4 #heg-ff4 8,bismuth in ,wire ,bar ,copper40 ,johnson1 ,f41 8,impurities in ,tough ,pitch ,copper containing ,arsenic40 ,proc4 ,inst4 of ,metals1 #aiaj1 vol4 iv42 ,no4 #b1 p4 #afc1 et seq4 ,johnson1 ,f41 8,the ,influence of ,impurities on the ,properties of ,copper40 ,metallurgical and ,chemical ,engineering1 ,oct4 #aiaj1 p4 #egj4 8,annealing of ,copper and ,diseases of ,copper40 ,ibid41 ,feb4 #aiaa1 p4 #hg4 8,notes on the ,metallurgy of ,wrought ,copper40 ,ibid41 ,august1 #aiaa1 p4 #cif4 ,see also ,standard ,specifications for ,copper ,wire-,bars 7recommendations by the ,committee of the ,american ,society for ,testing ,materials74 ,eng4 and ,min4 ,journ41 ,jan4 #bj1 #aiab1 p4 #aha4 ,,lecture ,,iii4 ,compounds of ,copper -- ,copper ,mattes -- ,the ,varieties of ,commercial ,copper -- ,ores of ,copper -- ,preliminary ,treatment of ,ores1 ,sampling4 ,compounds of ,copper4--,from the smelting point of view1 the three most important classes of copper compounds are the oxides1 the sulphides1 and the silicates4 ,copper ,oxides4--,of the oxides1 two are of importance--cuprous oxide1 ,cu#b,o1 and cupric oxide1 ,cu,o--the first-named particularly1 having extensive connection with smelting practice4 ,cuprous oxide is black when in the massive form1 and has a red hematite colour when powdered4 ,it is readily formed by the oxidation of copper1 and melts at a red heat without decomposition2 further heating in the presence of air produces the cupric oxide which is less fusible4 ,as has been already indicated1 cuprous oxide dissolves in the molten metal4 ,it is easily reduced to metallic copper by heating with carbon1 the metal being also obtained if the oxide be heated in the presence of reducing gases2 it combines readily with silica when heated1 yielding fusible silicates4 ,when cuprous oxide is heated with sulphide of iron1 the copper1 having a greater affinity for the sulphur than iron possesses1 enters into combination with it1 forming copper sulphide and iron oxide1 and if sufficient silica be present1 a silicate of iron slag is produced4 ,when melted with copper sulphide1 cuprous oxide yields metallic copper with liberation of sulphur dioxide according to the equation-- ,cu#b,s #b;,cu#b,o #f;,cu ,,so#b4 ,this reaction is a quantitative one1 and takes place in the ,direct ,process of ,nicholl and ,james as operated at ,swansea4 ,the excess of either constituent remains unchanged4 ,the reaction is of great importance in the processes of copper extraction1 since upon it depends the liberation of metallic copper from the sulphide1 both in the old roaster process and in the modern converter operation4 ,sulphides of ,copper4--,of the sulphides ,cu#b,s and ,cu,s1 the former only is of metallurgical importance4 ,it is grey black1 brittle1 and crystalline1 its melting point is about #a1ace ,c41 and its specific gravity1 when cold1 about #ee4 ,owing to the great affinity of sulphur for copper1 this element acts as practically the universal carrier of the metal in smelting work1 detaching the copper from all other forms of combination1 and collecting it as sulphide1 mixed with the sulphides of other metals1 particularly that of iron--copper sulphide and iron sulphide alloying in all proportions4 ,when copper sulphide is melted with an excess of sulphur1 it remains unchanged2 when melted with copper and subsequently cooled1 the sulphide and metal separate as such1 although it is believed that small amounts of copper are present in solid solution in the sulphide on solidification1 but that they separate from it during a dimorphic change in the material1 which occurs at about #ajc ,c4 ,the sulphide reacts with iron with liberation of some metallic copper1 and the formation of some iron sulphide which associates itself with the rest of the copper sulphide1 forming a matte4 ,this matte is not further affected by iron1 so that it is not possible to completely decompose copper sulphide by this means4 ,when heated in a powdered condition in excess of air1 copper sulphide is oxidised1 oxides of copper and sulphur being produced4 ,there occur probably several intermediate reactions1 and several intermediate products are formed1 but the main effect is represented by the equations-- ,cu#b,s #b,o #b;,cu ,,so#b #b;,cu ,o ,cu#b,o which take place simultaneously1 the copper represented in the first equation being oxidised spontaneously according to the second1 and the resultant is the reaction ,cu#b,s #c,o ,cu#b,o ,,so#b4 ,in the furnace operations1 some of the ,,so#b in the presence of air and oxidisable material1 and in contact with the heated brickwork becomes oxidised to ,,so#c1 which1 interacting with the oxides and sulphides present1 combines to form copper sulphate and cupric oxide4 ,at a higher temperature the sulphate is again decomposed to ,cu,o and ,,so#c1 some of which passes off and is free to oxidise more sulphide2 the rest is decomposed to ,,so#b and oxygen4 ,these reactions occur during the roasting of charges containing copper sulphides4 ,copper ,mattes4--,on smelting a furnace charge which contains both copper and sulphur1 the sulphur appears to have a stronger attraction for the copper than for any of the other metals usually present1 and only when this affinity has been satisfied is the excess sulphur free to combine with other constituents of the charge4 ,the fusible copper sulphide which is thus produced1 has the power of mixing completely with any more sulphides which may be present1 especially with sulphide of iron4 ,the fused sulphides resulting from such furnace operations are termed copper-mattes4 ,they may contain from a mere trace to upwards of #hj per cent4 of copper1 and in ordinary work1 sulphide of iron is the other constituent present in the greatest proportion1 but sulphides of nickel1 silver1 zinc1 or lead1 etc41 may also be found1 as well as arsenides and antimonides4 ,these facts relating to the collection of the copper as a constituent of a fused sulphide product1 form the basis of modern copper-smelting work4 ,in view of the practical importance of the mixed sulphides1 the diagram representing their equilibrium requires notice4 ,a number of workers have studied the question with widely differing results4 ,rntgen made an exhaustive investigation of the system ,fe,s--,cu#b,s1 and published a very complete diagram of the series1 working with ,fe,s and ,cu#b,s in the pure state4 ,the sulphides as commonly met with1 especially in smelting practice1 do not however1 occur as materials of the composition denoted by the formul ,cu#b,s and ,fe,s4 ,the ordinary commercial sulphide of iron corresponds more closely to the impure eutectic of the iron-,fe,s system1 containing about #he per cent4 of ,fe,s and #ae per cent4 of iron1 and melts at about #igj ,c41 whereas the pure ,fe,s has a melting point of upwards of #a1ahj ,c4 ,at the elevated temperatures of the copper-smelting furnace1 pure ,fe,s tends to lose sulphur and to assume the composition of the eutectic4 ,there are1 further1 good reasons for believing that copper sulphide behaves in a somewhat similar manner1 so that the series of sulphides constituting the mattes of practice are not represented by pure materials so well as by a series composed of mixtures of the respective eutectics4 ,the diagram of this series of industrial sulphides was worked out by ,hofman1 ,caypless1 and ,harrington1 and gives a fair summary of the melting points of the series of mattes4 ,it is reproduced in fig4 #h4 ,the temperatures may be supplemented by ,gibb's determinations of #a1aba ,c4 for the #gag per cent4 copper matte1 and #a1jih ,c4 for the #hj per cent4 matte4 ,the problem of the constitution of mattes is1 however1 a very complex one1 and is not yet satisfactory settled4 ,an interesting view was put forward by ,gibb and ,philp4 ,mattes corresponding to the formula #e;,cu#b,s 4 ,fe,s 7copper #gag per cent471 when examined microscopically1 appeared to be homogeneous1 and indicated some form of combination between the sulphides in these proportions4 ,lower-grade mattes were assumed to consist of this compound substance and excess ,fe,s4 ,iron sulphide was held to be capable of carrying a certain quantity of copper in solution1 and mattes might1 therefore1 carry this copper1 according to the amount of excess ,fe,s which they contained4 ,within certain limits the lower the grade of the matte--i4e41 the more ,fe,s present--the more copper was held in solution1 and with a fall of temperature this solubility was lessened1 and moss copper was set free in the solid matte4 ,illustration3 ,fig4 #h4--;,freezing-,point ,curve of ,iron-,copper ,sulphides 7,mattes74 ,deposition of copper may also be accounted for by a variation in the solubility for copper1 accompanying the well-marked dimorphic change occurring in ,fe,s at #acj ,c4 whilst another possible cause of the separation of moss copper is the partial decomposition of ,cu#b,s1 being effected1 as previously indicated1 by the free iron of the iron-,fe,s eutectic which constitutes the iron sulphide component of copper mattes4 ,the whole subject is thus of considerable complexity1 and involves questions of thermal and chemical equilibrium4 ,the appearance1 chemical constitution1 and physical properties of mattes vary according to the rate of cooling1 and are further influenced by the nature and amount of the impurities they contain1 and the following statement must be understood to be more or less general3--,usually low-grade mattes 7up to #bj per cent4 or so of copper7 are more or less stony in fracture1 with a bluish-purple colour2 as the copper contents increase1 a reddening of the colour occurs1 and also an increase in the crystalline character and brittleness4 ,considerable quantities of moss copper are present in these mattes4 ,beyond #cj per cent4 of copper1 increased softness and brittleness result1 with a darkening towards blue-black in the colour1 whilst with the #fj to #gj per cent4 mattes the colour becomes in general of a steel-grey hue4 ,increase in the copper contents leads to an increase in the density--a matter which has important applications in connection with the economical separation of matte from slag1 and the slag-losses in smelting practice4 ,the specific gravity of the #ac per cent4 copper matte is about #dhj4 #dc #eah4 #fj #edb4 #hj #eee4 7,gibb and ,philp47 ,the density in the fluid state1 which is the important condition in smelting1 is less than this1 and may indeed be somewhat different1 owing to changes in the constitution of the material4 ,copper ,silicate is formed by the action of copper oxide and silica on heating4 ,the silicate is decomposed when heated in the presence of sulphides1 resulting in the formation of sulphide of copper and silicate of the second metal1 in consequence of the great affinity of copper and sulphur4 ,upon this fact depends the extraction of copper from various silicate ores1 as well as the cleaning of slags high in copper1 which are often added to the sulphide charges in the furnace with this object4 ,when heated with iron1 the silicate is reduced to metallic copper with the production of silicate of iron2 it is also reduced by carbon in the presence of metallic oxides capable of uniting with the silica which is liberated4 ,the ,varieties of ,commercial ,copper4--,the copper employed industrially comes into the market in widely differing forms4 ,different varieties are named according to the method of manufacture1 the uses for which they are intended1 the locality in which they are produced1 or by special trade names4 ,the most important variety is3-- ,electrolytically-refined ,high-conductivity ,copper1 which is largely used for electrical work4 ,the methods by which it is produced ensure that most of the impurities inimical to high conductivity have been removed1 and the metal is specially free from arsenic1 antimony1 and bismuth1 as well as from silver and gold4 ,as ordinarily produced at the electrolytic refinery1 it is in the form of cathode plates1 often about #c feet #b feet #f inches by inch thick1 weighing #aej to #agj lbs4 ,it is then remelted in order to bring it 8up to pitch10 and to give it the necessary mechanical properties1 so that it may be transformed at once into the particular form suitable for the electrical purposes intended4 ,such metal often comes into the market in the form of wire-bar ingots1 cakes1 or billets1 weighing from #gj to #ejj lbs4 when in bar form1 and from #ajj to #djj lbs4 when in other shapes4 ,electrolytic copper is also suitable for the manufacture of alloys4 ,lake ,copper4--,the copper ores of the ,lake ,superior district are particularly pure1 and on smelting and furnace-refining yield a metallic product of great purity which also possesses good mechanical properties4 ,it is1 therefore1 particularly suitable for electrical work4 ,by reason of its satisfactory properties1 ,lake copper realises prices which usually rule somewhat higher than those of ordinary electrolytic copper as quoted on the ,new ,york market4 ,best ,select ,copper4--,for the production of copper alloys1 such as best brass1 etc41 it is essential that the copper should be pure4 ,the impurities which are present in ordinary tough copper1 and which may be valuable for imparting strength to the material1 have a very harmful effect when present in alloys4 ,in the older ,welsh process of manufacturing copper1 a special method was employed for obtaining metal free from these impurities1 especially arsenic and antimony4 ,this was known as the 8best selecting0 process4 ,the principle underlying the method was to conduct the furnace operations to the stage at which a small quantity of copper1 known as 8copper bottoms10 was obtained4 ,the metal so produced has the property of collecting from the rest of the matte-charge in the furnace1 the gold1 the silver1 and the great bulk of the other impurities1 owing to its greater solvent power for them4 ,as a result1 the greater part of the matte 78white metal07 was left pure1 and from this material the copper was extracted by continuing the furnace operations in the usual manner1 the resulting product being known as 8best select0 7,b4,s47 copper4 ,the process was later used principally for the extraction of the gold in the charge1 rather than for obtaining specially pure copper4 ,the product is essentially a ,british one1 and was largely used for the manufacture of high quality alloys4 8,tough ,pitch ,copper40--,the operation of 8bringing copper up to pitch0 has for its object the imparting to the metal of the toughness and mechanical strength required for industrial service4 ,the process resolves itself into the adjustment of the correct proportion of oxygen1 the function of which is largely to eliminate the gases from the copper1 or to overcome their deleterious effects1 as well as to convert the otherwise more injurious metalloid impurities into a less harmful form4 ,in modern practice1 practically all copper is brought up to pitch1 but it is useful to distinguish between tough-pitch furnace-refined copper and tough-pitch electrolytic copper4 ,the former is the brand to which the general term 8tough pitch copper0 is best applied1 this name having been given to the product from the refining furnaces of the old ,welsh and similar processes4 ,before the converter method was introduced into copper practice1 the furnace processes for extracting copper from the ores resulted in the production of a crude 8blister0 copper1 into which several injurious constituents1 if originally present in the ore1 found their way4 ,the principal impurity was usually arsenic4 ,although this was also removable by special refining methods1 and with some difficulty1 it was known1 as has been indicated1 that when arsenic is present under suitable conditions and in proper proportions1 it is capable of imparting considerable strength and rigidity to the metal4 ,such copper being particularly suited for various engineering and mechanical uses1 the arsenic being sometimes even specified for and purposely added--as in fire-box plates and stay bolts1 though it is never employed for conductivity work or for the manufacture of alloys if any considerable proportion be present--the metal found a ready market when brought to pitch4 ,tough pitch copper may thus vary largely in composition1 especially in arsenical contents1 up to about the #je per cent4 already indicated as being mechanically very useful4 ,the actual process1 as used for bringing all classes of metal to pitch1 will be described in detail later1 it being practically the same whether conducted on furnace-refined metal1 converter metal1 or on electrolytic copper1 as a necessary preliminary to casting into the various forms of ingot in which it is to be marketed4 ,in preparing the tough metal from crude copper1 the more oxidisable impurities 7iron1 sulphur1 etc47 are first removed by a thorough oxidation during or after melting down1 this being known as 8airing40 ,the operation oxidises some of the copper1 and it is probable that the copper oxide thus formed plays an important part in getting rid of impurities4 ,by the time they have been thoroughly expelled1 the metal is considerably over-oxidised4 ,samples taken at this stage exhibit the following characteristics3--,the ingot has a depression down the centre line1 the material is very brittle1 the fracture is brick-like in texture and purple-red in colour1 whilst much copper oxide and oxidule-eutectic are seen on examination under the microscope4 ,this material is known as ,dry ,copper2 it is merely an intermediate product1 and is commercially useless4 ,the excess of oxygen is removed by 8poling0--that is1 reduction1 effected largely by charcoal1 as well as by reducing gases--successive samples showing less and less of the characteristics of dry copper4 ,the surface becomes level1 the metal exceedingly tough1 the fracture fine-grained to silky in texture1 and a fine salmon-pink in colour4 ,with satisfactory mechanical properties1 the metal has now become tough pitch copper4 ,if the poling--that is1 the reduction of the oxidised constituents of the tough pitch copper--be carried too far1 the metal becomes brittle again1 being known as over-poled copper4 ,the fracture then tends to become coarse and fibrous1 the colour lighter1 and the upper surface of the ingot exhibits a ridge4 ,the reasons for these effects have not yet been quite fully explained1 but there is no doubt that they arise from the removal of oxygen from the oxygenated constituents1 and the withdrawal from the metal of the protecting influence of the cuprous oxide4 ,such influences are to some extent physical1 since they prevent the retention of the reducing gases2 partly mechanical1 in their effects on the properties of the metal per se1 and partly chemical1 as the oxide had probably entered into chemical combination with some of the objectionable impurities1 producing compounds1 in which form they were much less harmful4 ,the removal of this oxygen from the metal breaks down such combinations1 leaving the reduced impurity again to exercise its destructive effects on the properties4 ,over-poled copper1 like dry copper1 being brittle1 is commercially useless as such1 and is really an intermediate product1 the metal being brought to pitch again by further aration to make it 8dry10 after which it may be poled back to correct pitch4 ,as already stated1 the over-poling effects are not due to any intrinsic action of carbon directly on the copper itself4 ,summarising1 it may be stated that the most important commercial varieties of copper are3-- ,electrolytically-refined metal1 employed for electrical work 7also for alloy-making74 ,tough ,pitch ,copper for engineering uses4 ,best ,select ,copper for alloy manufacture4 ,and1 in addition1 ,lake ,copper and some ,converter ,bars4 ,a number of unrefined metallic products met with in practice include3-- ,converter ,bars4--,the product from the ,bessemer operation on copper mattes4 ,most converter metal is subsequently electrolytically refined1 but several varieties of ,australian and ,american copper are put on the market direct in this form4 ,being produced from fairly pure ores1 which carry but little silver and gold1 the converter metal may be sufficiently pure to render electrolytic refining unnecessary1 and too low in gold and silver values to make such an operation profitable4 ,cathode ,copper is the product from the electrolytic refinery1 and is usually remelted1 brought up to pitch1 and cast into ingots previous to use4 ,black ,copper is produced by the smelting of oxide ores1 and is subsequently refined4 ,cement ,copper is produced by wet processes1 usually by precipitation from copper-bearing solutions by means of iron1 the product being a rather impure reddish-brown spongy mass4 ,many varieties contain arsenic4 ,it requires melting and subsequent refining to adapt it for service4 ,blister ,copper was the name given to the crude metal from the older type of furnace operations4 ,such copper contained large quantities of gas1 particularly ,,so#b1 which1 tending to escape at the moment of solidification in the mould1 gave a blistered appearance to the surface4 ,it contained #if to #ih per cent4 of metallic copper1 and was subsequently refined4 ,the term is generally applied still to all crude copper exhibiting similar features4 ,chili ,bar is an impure copper imported from ,chili for refining4 ,the composition varies1 the metal usually containing #if to #ih per cent4 of copper1 with indefinite quantities1 sometimes small1 of undesirable impurities4 ,appended is a series of representative analyses of various copper products1 compiled from different sources4 ,the composition of such material as tough pitch copper and the various cruder varieties is1 however1 subject to very great variation4 ,the ,sources of ,copper4--,copper ores usually consist of various minerals of copper mixed with those of many other metals1 and accompanied by very varied gangue1 according to the locality in which they are found4 ,they are best classified under three groups3-- 7#a7 ,native ,ores4 7#b7 ,sulphide ,ores4 7#c7 ,oxide ,ores4 ,the most important points to be noted with regard to the distribution of these different classes are that-- 7#a7 ,native ores are localised in their occurrence1 being chiefly confined to the ,lake ,superior district4 ,,table ,,iv4--,,analyses ,,of ,,various ,,commercial ,,coppers4 ,copper ,gold ,silver ,lead #a4 ,electrolytic conductivity #iihi nil nil nil copper1 #b4 ,lake copper1 #iigg nil #jjbi nil #c4 ,best select copper1 #iige 44 44 #jjbd #d4 ,tough pitch copper1 #iida 44 44 #jjgj #iibe 44 #jcf #jjajc #e4 ,copper fire-box plate 7ran #ejj1jjj miles1 ,met4 ,ry471 #ihgj #jjjjajjcdf #jdjhe ,,intermediate ,,products-- ,refined converter copper1 #iibe 44 #jcf #jjajc #iijh 44 #jcj #jjjhe ,cathode copper1 44 44 #jjja #jjjjed ,black copper1 #idci 44 #jaa #jai #iggj 44 #jbacc #jgh ,cement copper 7,spanish71 #eaij 44 #bce #ade #gfic #jaj 44 trace ,blister copper1 44 #jjjjijjd #jjdb ,chili bar1 #ihfj 44 44 trace ,arsenic ,antimony ,bismuth ,iron #a4 ,electrolytic conductivity #jjaf trace nil #jjdb copper1 #b4 ,lake copper1 nil trace nil #jjjgg #c4 ,best select copper1 #jjbe trace #jjaa #jaj #d4 ,tough pitch copper1 #jcbj trace #jjaj #jjaj #jjbaa #jfcj #jjjdd 44 #e4 ,copper fire-box plate 7ran #ejj1jjj miles1 ,met4 ,ry471 #jcgbf #jjcdf #jjcfj #jjjfi ,,intermediate ,,products-- ,refined converter copper1 #jjbaa #jjfcj #jjjdd 44 #jjbij #jjbed #jjjce trace ,cathode copper1 #jjjjcd #jjjjh #jjjjc 44 ,black copper1 trace 44 44 44 #jjeb #jbchj #jjjce #jag ,cement copper 7,spanish71 #bie #jej #jie #gjj #acb #jjb 44 #gf ,blister copper1 #jajh #jaeg #jjee #jd ,chili bar1 #jajj trace nil #jjji ,nickel ,tin ,oxygen ,sulphur #a4 ,electrolytic conductivity #jjjf 44 #jjjh nil copper1 #b4 ,lake copper1 #jjadf nil #jjgj 44 #c4 ,best select copper1 #jjfa 44 #jadc 44 #d4 ,tough pitch copper1 #jjfj 44 #jabj 44 44 44 #jbhd 44 #e4 ,copper fire-box plate 7ran #ejj1jjj miles1 ,met4 ,ry471 #jcjci 44 #jjaha #jjjfd ,,intermediate ,,products-- ,refined converter copper1 44 44 #jbhd 44 44 44 #jab #jja ,cathode copper1 44 44 #jjje 44 ,black copper1 #bjd #jjg 44 #jhj 44 44 44 #jgif ,cement copper 7,spanish71 44 44 #afjj #eaj 44 44 44 #jdh ,blister copper1 #jj-jb #jj-je 44 #jaab ,chili bar1 44 44 44 #jiji 7#b7 ,sulphide ores supply the bulk of the world's copper1 constituting upwards of #hj per cent4 of the total4 7#c7 ,the oxidised ores are found in most copper districts1 though usually to only a limited extent4 ,they are often gossan deposits produced by weathering or by decomposition of sulphides1 hence are generally found nearer the surface1 changing to sulphide with depth4 ,the supply of copper from oxidised ores1 which was at one time very large1 is decreasing rapidly1 and the greater proportion of the copper now obtained from them comes from the more recently developed deposits1 of which those at ,tanganyika afford an example4 ,more than #bjj minerals which contain copper are known1 but most of them are unimportant from the smelting point of view4 ,the characteristics of the more noteworthy may be fully studied from text-books of economic mineralogy4 ,copper ,ores--,native ,copper4--,occurs extensively in the ,lake ,superior district of ,michigan1 in ,precambrian rocks1 sparingly in ,new ,mexico and ,china1 but seldom anywhere else in workable quantities by itself4 ,copper barilla or copper sand1 an impure native metal from ,chili1 was formerly of importance4 ,native copper constitutes about #bj per cent4 of the ,north ,american supply4 ,it yields metal of exceptional purity1 and the brands of ,lake copper reach a very high standard1 both as regards electrical and mechanical properties4 ,a still purer variety is the native metal from ,yunnan1 ,china4 ,the ,lake ,superior copper occurs in three formations3-- 7a7 ,vein deposits1 from which the enormous masses of copper are taken out4 7b7 ,copper-bearing ash beds1 of amygdaloidal diabase4 ,chief mine1 ,quincy4 7c7 ,beds of conglomerate in which the cementing material consists partly of copper4 ,this last class of deposits yields three-quarters of the ,lake copper supply4 ,their average copper content is #bi per cent4 ,the chief mines are the ,calumet and ,hecla1 the ,tamarack and the ,atlantic1 all situated on one ore chute measuring #c miles in length1 and worked to a depth of #d1jjj feet4 ,sulphide ,ores3 ,chalcopyrite 7,copper ,pyrites7 is by far the most widely distributed ore of copper1 and furnishes the greater proportion of the world's supply4 ,the formula when pure is ,cu#b,s4 ,fe#b,s#c 7,cu #cdd1 ,fe #cje1 and ,s #cea per cent471 but usually the ore is not in this condition1 being mechanically mixed with large quantities of iron pyrites1 and very often with pyrrhotite4 ,it occurs principally in the older crystalline rocks1 often in bedded veins4 ,the value of copper veins below the limit of surface decomposition is nearly always due to chalcopyrite4 ,silver and gold are often carried1 as well as other metals4 ,it occurs extensively in ,montana1 ,arizona1 ,tennessee1 ,canada1 ,chili1 ,japan1 ,spain1 ,cornwall1 etc4 ,chalcopyrite ores vary considerably in copper contents2 thus ,tennessee ores contain about #be per cent4 of copper1 ,montana ores #e to #e per cent4 7with gold and silver valued at about #aa per ton of copper71 whilst the ,arizona ores vary1 being often rich4 ,chalcocite 7also known as copper glance or redruthite7 is much less important4 ,the copper contents are #gih per cent4 when pure1 but such a condition is rare1 although the ore seldom contains less than #ej per cent4 of copper4 ,below this proportion it often tends to pass into bornite1 and then to chalcopyrite4 ,it is found in ,montana1 is an important ore in ,arizona 7,clifton district71 and occurs also in ,cornwall4 ,other important sulphides include3-- ,bornite 7,erubescite1 ,peacock copper ore71 #c;,cu#b,s4,fe#b,s#c1 occurring in ,cornwall1 which passes with depth into chalcopyrite4 ,tetrahedrite 7,fahl ore71 a very complex sulphide of copper1 iron1 lead1 zinc1 with arsenic1 etc4 ,it is often rich1 and carries silver values4 ,oxidised ,ores4--,the most important of the oxidised ores are-- ,malachite1 ,cu,c,o#c4;,cu7,,oh7#b1 containing1 when pure1 #egc per cent4 copper 7#gcg ,cu,o72 is widely distributed1 but usually occurs as such in non-paying quantities except in a few particular localities4 ,it is found in the upper parts of the veins4 ,whenever found with sulphide ores1 it is an extremely useful material to mix in the charge1 as it supplies oxygen as well as copper4 ,malachite is still an important source of the metal in ,mexico1 ,chili1 and ,bolivia1 though not quite so much so as formerly1 whilst it is specially important in the ,tanganyika 7,katanga7 deposits1 of which it constitutes the greater portion so far developed4 ,cuprite1 ,cu#b,o1 contains #hhh per cent4 copper1 when pure4 ,it is widely distributed1 but is never found by itself in paying deposits1 though in the early days of mining and smelting it was an important source of metal1 since it was easily reduced1 and consequently was cheaply worked4 ,melaconite1 ,cu,o1 contains #gih per cent4 copper1 when pure2 is fairly widely distributed1 although hardly ever in sufficient quantity to pay4 ,in one or two localities1 however--viz41 ,tennessee1 ,north ,carolina1 and ,virginia--it was formerly an important source of the metal4 ,the deposits were at first very promising1 as they consisted largely of very rich melaconite ore2 this was however1 quickly worked out1 the ordinary heavy chalcopyrite with #be per cent4 copper being struck below4 ,other oxidised ores include-- ,azurite1 #b;,cu,c,o#c4 ,cu7,,oh7#b1 and ,atacamite1 ,cu,cl#c4 #c;,cu7,,oh7#b1 from ,chili4 ,in modern work1 the chief ore smelted is impure chalcopyrite4 ,carbonate and oxidised ores1 when they can be obtained1 are mixed with it1 increasing the concentration and shortening the process2 except under certain special circumstances4 ,preliminary ,treatment of ,ores4--,the treatment of ores preparatory to smelting includes the processes of sampling1 wet concentration1 agglomeration of fines1 and roasting4 ,sampling4--,since sampling is not a part of the extraction process proper1 in copper smelting1 it will be convenient to deal with the subject separately here4 ,it is important that ores and all other products entering or leaving the works1 as well as many of the intermediate products of the various operations1 should be properly sampled and assayed4 ,great attention is paid to this point at the best organised smelters1 since only by this means can the work of the plant and of its several departments be properly checked and controlled4 ,each works has its own special method of taking samples from the stocks1 the ,anaconda practice1 for example1 being to pass the whole of the first-class ore1 amounting in quantity to #be1jjj tons per month1 through the sampling mill1 whilst of the poorer1 second-class1 ore for concentrating1 every fifth car-load is sampled4 ,there are many different types of sampling plant1 and the methods employed vary also1 but the principle is much the same in each case--namely1 to use some automatic device which cuts out and deflects a certain proportion of the stream of ore on its course through the mill2--the deflected portion being crushed finer1 and a part of it again cut out and deflected2 repeating the operation in this way three or four times4 ,the sampling process and plant at ,anaconda is so representative of the best practice1 that it may be reviewed in brief1 as an example4 ,illustration3 ,fig4 #i4--,outline of ,sampling ,scheme1 ,anaconda4 ,illustration3 ,fig4 #aj4--,section through ,sampling ,mill4 ,the ,anaconda ,sampling ,plant is entirely automatic in its action4 ,the mill is built in two sections1 each of which treats #a1hjj tons daily4 ,each section consists of a set of four sampling machines with intermediate crushers4 ,the ore goes from the bin to a ,blake crusher1 breaking to #c-;inch to #d-;inch size2 the crushed ore is elevated and fed down a chute to the first sample cutter1 which takes out one-fifth 7#djj lbs4 per ton7 as a sample1 and deflects the rest down another chute4 ,the sample is crushed further in a ,blake crusher1 and passes a second sample cutter 7rather smaller in size71 which again takes out one-fifth 7#hj lbs4 for every original ton of ore71 and rejects the rest down the 8rejects-chute40 ,the sample is now crushed in rolls1 a third cut of one-fifth 7#af lbs4 of the ton7 taken as before1 the rest rejected4 ,the sample passes to a final set of crushing rolls1 and the last cut of one-fifth is taken4 ,hence each ton of ore is represented eventually by #cb lbs4 of sample4 ,the sample cutter employed is of the ,brunton form4 ,it consists essentially of a curved boat of #abj arc1 which rotates to and fro on a central spindle4 ,the top is open2 one side has one hole cut in1 the other has two1 the area of the latter being together four times that of the single one1 so that the falling stream is cut continually1 and one-fifth is deflected to one side1 falling down a chute to the next crusher1 whilst the other four-fifths fall from the other side to the rejects-chute4 ,illustration3 ,fig4 #aa4--;,brunton ,sampler4 ,the above description is quite general1 several details for certain classes of ore having been omitted1 but it gives a fair idea of the general principles underlying such work4 ,the final sample1 say #c1bjj lbs4 per #a1jjj tons of ore1 is mixed on an iron plate on the floor1 quartered several times by a ,brunton shovel1 and the chosen sample then ground in an ,englehardt mill 7small ,gates' crusher with two discharges74 ,the material is passed through a #a-;foot riddle of #ajj mesh wire cloth1 the very small quantity of coarser stuff remaining1 is bucked down and added1 and the whole is then thoroughly mixed in a canister of #a foot side gripped at opposite corners1 and rotated mechanically4 ,references4 ,constitution of ,copper ,mattes4 ,keller4 ,mineral ,industry1 vol4 ix41 #aijj1 p4 #bdj4 8,elimination of ,impurities from ,copper ,mattes40 ,rntgen4 ,metallurgie1 vol4 iii41 #aijf1 p4 #dgi4 ,hofman1 ,caypless1 and ,harrington4 ,trans4 ,amer4 ,inst4 ,min4 ,eng41 vol4 xxxviii41 #aijh1 pp4 #adb-aec4 ,gibb and ,philp4 ,trans4 ,amer4 ,inst4 ,min4 ,eng41 vol4 xxxvi41 #aijf1 p4 #ffe4 ,heyn and ,bauer4 ,metallurgie1 vol4 iii41 #aijf1 p4 #hd4 ,fulton and ,goodner4 ,trans4 ,amer4 ,inst4 ,min4 ,eng41 vol4 xxxix41 #aijh1 pp4 #ehd-fbj4 ,refining of ,copper4 ,h4 ,o4 ,hofman1 ,r4 ,hayden1 and ,h4 ,b4 ,hallowell1 8,a ,study in the ,refining and ,overpoling of ,electrolytic ,copper40 ,trans4 ,inst4 ,amer4 ,min4 ,eng4 ,hofman1 ,green1 and ,yerxa1 8,a ,laboratory ,study of the ,stages in ,refining ,copper40 ,trans4 ,amer4 ,inst4 ,min4 ,eng41 #aijd1 vol4 xxxiv41 pp4 #fga-ie4 ,stahl1 8,ueber ,raffination1 ,analyse and ,eigenschaften des ,kupfers40 ,berg4 and ,httenmnnische ,zeitung1 #ahhi1 vol4 xlviii41 pp4 #cbc-d2 #ahij1 vol4 xlix41 p4 #cii2 #ahic1 vol4 lii41 p4 #ai2 #aija1 vol4 lx41 pp4 #gg-gi4 ,keller4 ,mineral ,industry1 vol4 vii41 p4 #bde1 et seq4 ,sampling4 ,d4 ,w4 ,brunton1 8,modern ,practice in ,ore ,sampling40 ,mining and ,scient4 ,press1 ,oct4 #cj1 #aiji4 8,theory and ,practice of ,ore ,sampling40 ,trans4 ,amer4 ,inst4 ,min4 ,eng41 vol4 xxv41 p4 #hbf4 ,,lecture ,,iv4 ,modern ,copper ,smelting ,practice -- ,preliminary ,treatment of ,ores3 ,concentration1 ,briquetting1 ,sintering -- ,the ,principles of ,copper ,smelting -- ,roasting4 ,modern ,copper ,smelting ,practice4--,until recently1 modern smelting practice has been understood to involve the production of a matte containing from #dj to #ej per cent4 of copper1 which is then bessemerised4 ,there are however proceeding at present 7owing to the successful working of basic-lined converters7 developments which indicate that such practice may1 within a few years1 be modified very considerably in the direction of the converter treatment of lower-grade mattes4 ,until such operations become successfully established and generally adopted1 the production and subsequent bessemerising of #dj to #ej per cent4 matte will be here dealt with as constituting modern practice2 particularly since1 generally speaking1 the principles involved are equally applicable to the modified methods now being developed4 ,preliminary ,treatment of the ,ore4--,the factors which have to be considered in drawing up a scheme of treatment for the supply of ores shipped to a smelter are exceedingly numerous1 and will be discussed in due order4 ,there are no hard and fast principles which determine such schemes1 yet a number of considerations must be noted concerning the treatment preliminary to the actual smelting of the ores4 ,such preliminary treatment may include-- ,a4 ,concentration or ,wet ,dressing4 ,b4 ,agglomeration of ,fines--7a7 ,briquetting1 7b7 ,sintering4 ,c4 ,roasting4 ,a4 ,concentration or ,wet ,dressing4--,in treating the ores of copper1 it may be noted that in general-- ,native ,ores1 unless very massive1 are usually dressed in a special manner peculiar to themselves--e4g41 stamp-milling4 ,oxide ,ores are rarely wet-dressed4 ,they present much difficulty in treatment on account of their comparatively low density1 which makes efficient wet concentration almost impossible1 whilst heavy losses in the tailings generally accompany such operations4 ,sulphide ,ores4--,no definite rules can be laid down as to whether the ore should be wet-dressed or not2 the treatment depends altogether on attendant circumstances1 such as--7a7 the character of the ore1 7b7 the concentration of the copper desired in the first smelting operation1 and 7c7 the smelting method and furnaces adopted4 ,wet concentration is only profitable when the copper ore is of low grade1 and then only under suitable conditions4 ,thus the low tenor may be due to admixture with much gangue or with other sulphides1 or both4 ,a massive low-grade pyritic ore carrying but little gangue is not suitable for such treatment1 since the mixed sulphides are not separated from one another by wet dressing1 and consequently but little enrichment of the copper in the dressed product would be possible2 apart altogether from other considerations4 ,such is the case1 for instance1 with the ,tennessee ores carrying about #bj per cent4 of copper and only #be to #ce per cent4 of gangue4 ,an ore with a self-fluxing or almost self-fluxing gangue might allow of its copper being concentrated more cheaply and conveniently by direct smelting than by wet dressing1 this depending1 of course1 on the local conditions4 ,in other cases a balance has to be struck as to whether the circumstances are more favourable for removing the excess of gangue by means of crushing and treatment in a stream of water1 or by slagging it off in a furnace with the addition of suitable fluxes4 ,in many cases1 with low-grade ores1 the former treatment is the cheaper4 ,the case of the low-grade ores of the ,butte1 ,montana1 district1 affords a good example of these considerations4 ,this ore contains #e to #e per cent4 copper1 with a large quantity of highly siliceous gangue4 ,it was found that the purchase and carriage of sufficient flux1 and the cost of carrying out this fluxing operation was so expensive that it was cheaper to build a concentrator and smelter at ,anaconda1 #cj miles away--in a locality where a suitable water supply was available for the dressing--and to convey the ore this distance in order to concentrate it by a wet method4 ,the dressed ore assays #i to #aj per cent4 of copper4 ,it is important to note that the process of wet dressing involves crushing the ore1 and yields the product in a more or less finely divided form4 ,most copper sulphide minerals are exceedingly brittle1 and break up to a very small size on crushing for concentration1 so that the copper concentrates usually include a large quantity of fine material4 ,there are two general types of furnace available for smelting--reverberatory furnaces and blast furnaces--and the questions of the desirability and of the degree of crushing and concentration depend to a large extent on the plant and furnaces adopted or proposed4 ,blast-furnace treatment has hitherto often been considered the most economical process for smelting copper ores1 especially with regard to fuel costs1 but for many reasons it is not a convenient or efficient furnace for the direct treatment of fine material4 ,when it is desired to employ the blast furnace1 it is necessary to make up charges consisting1 to as great an extent as possible1 of coarse material4 ,in consequence1 when concentrating ores with a view to subsequent blast-furnace treatment1 the degree of crushing and dressing has to be modified with these factors in view2 otherwise a further preliminary manipulation of the fine concentrates that are produced is rendered necessary4 ,such modified dressing schemes involve a maximum of coarse breaking and screening1 the crushing and separating stages being thus very gradual1 and the units in the plant are multiplied1 whilst the process is rendered complex in consequence4 ,with the greatest care1 moreover1 large quantities of fines are bound to be produced1 and have to be dealt with by some means other than immediate blast-furnace treatment4 ,dressing schemes and plant for sulphide copper ores are thus often complicated1 particularly for the recovery of the values from the finer material1 and cannot be discussed at any length here4 ,reference should be made to ,richards or other standard works on the subject4 ,as representative of wet-dressing practice1 the ,anaconda scheme may be noted1 as summarised below4 ,there are eight mills1 each treating #a1jjj tons of ore per day1 and conducting the-- ,coarse crushing in ,blake crushers4 ,coarse sizing by trommels4 ,coarse separation on ,harz jigs of #a-;inch and -inch feed4 ,middlings crushing in rolls4 ,middlings sizing by trommels4 ,middlings separation on fine jigs of #g1 #e1 #b1 #a1 and #a millimetre feed4 ,finest crushing in ,huntingdon mills4 ,fines settling by spigot settlers4 ,fines separation on ,wilfley tables 7#dga are in use on the plant74 ,the muddy water goes to enormous settling ponds1 where the slime settles down1 gradually drains1 and dries1 and it is afterwards used for various purposes during the smelting operations2 being dug out in the form of a fine clay4 ,a new form of centrifugal apparatus 7the ,peck7 is now being installed for the separation of this material4 ,the subsequent treatment of the products from the concentrating operation is indicated in the diagram 7fig4 #ab71 from which it will be seen that the-- ,coarse ,concentrates1 #a1 7and 7 inch size1 are smelted in the blast furnaces4 ,fine ,concentrates1 #g1 #e1 #b1 #a1 and #a millimetre size1 pass to the roasters1 and thence to the reverberatory furnaces4 ,slimes are used for briquetting1 and several other operations4 ,tailings pass to the dump4 ,illustration3 ,fig4 #ab4--,outline of ,smelting ,scheme at the ,anaconda ,smelter1 ,montana1 ,u4,s4,a4 ,b4 ,agglomeration of ,fines4--,it has just been seen that the wet concentration of ores 7considered advisable in a large number of cases7 results in the production of a considerable quantity of fine concentrate1 a form of material not well suited for immediate blast-furnace treatment4 ,in addition1 smelters often receive considerable amounts of fines in the smelting-ore supply1 which it is not unusual to screen out and to treat separately from the coarser materials4#d ,the alternatives for the treatment of fines1 and more particularly of fine concentrate1 include smelting in reverberatory furnaces 7usually after roasting72 blowing into the converter 7a new process still in the experimental stage72 and blast-furnace treatment after suitable preparation4 ,blast furnaces have many advantages which lead to their extended use in copper smelting practice1 but one important feature1 which also applies to the smelting of other metals1 has always to be borne in mind in this connection--viz41 that material in a finely divided state cannot be treated directly in a blast furnace without heavy losses1 and the working of the furnace on such charges is not efficient4 ,no material less than to inch in size1 especially when in the form of sulphides1 should be fed as such into a modern blast furnace4 ,fines in the furnace lead to-- 7a7 ,accretions1 7b7 ,irregular working of the furnace and the charge1 7c7 ,clotting and low concentration1 7d7 ,heavy flue-dust losses1 and their presence is often the cause of much trouble at many of the modern smelters4 ,the agglomerating of the fines is1 therefore1 a very important preliminary in any scheme of treatment involving the employment of the blast furnace on such material4 ,agglomerating is usually performed by one of two methods--7#a7 briquetting1 7#b7 sintering4 ,of these1 briquetting has hitherto been in very general use1 but several advantages connected with the sintering process and the resulting product are leading to its adoption with much success in several localities1 and attracting for it considerable attention at present4 7a7 ,briquetting4--,among the advantages of briquetting is the fact that it utilises large quantities of the copper-bearing slime produced at the concentrating plant1 this material often possessing good binding properties which render it very suitable for briquette-making4 ,illustration3 ,fig4 #ac4--,sketch ,plan of ,briquetting ,plant4 ,illustration3 ,fig4 #ad4--,section through ,auger-,former1 showing ,briquetting ,mechanism1 of ,chambers' ,machine4 ,illustration3 ,fig4 #ae4--;,chambers' ,briquette-making ,machine4 ,the type of plant in use at different smelters varies considerably1 the method adopted being either the stamping out of the briquettes1 or by the application of steady pressure1 the production of bars which are then cut up to convenient size4 ,the constituents used depend naturally on the materials available at the smelter1 briquettes1 both with lime and without1 being made4 ,the ,briquetting ,plant at ,anaconda4--,the operation of this plant affords a good example of the process4 ,its working is very successful in using up much fine concentrate1 as well as the slime from the ponds1 which acts as binding material and at the same time supplies copper4 ,briquette1 indeed1 constitutes one of the biggest items of the charge for the ,anaconda blast furnaces4 ,there are four ,chambers' machines in use1 making #hdj tons of briquettes daily4 ,the briquettes consist of slime1 fine first-class ore screenings 7 -inch size71 fine concentrate from the dressing plant1 and coke 7which is recovered from the reverberatory furnace gratings74 ,the quantities used daily are somewhat as follows1 though they are naturally subject to some variation1 depending on supplies3-- ,slime1 #ejj tons4 ,first-class ore screenings1 #cjj ,fine concentrate1 #bjj ,coke1 #gj and the composition of the briquettes is about-- ,copper1 #ej per cent4 ,ferrous ,oxide1 #af ,silica1 #de to #ej ,sulphur1 #ae ,lime1 #jg ,moisture1 #aej ,coke1 #ej ,the different materials are stored in bins1 and fed through doors to conveyors1 which discharge on to an elevator leading to a divided hopper1 each division of which feeds a pug-mill4 ,the pug mills are long troughs in which inter-moving bladed spindles rotate1 churning up the materials2 the mixing being assisted by a water supply from above4 ,the mixture passes down a chute to one end of an auger machine1 from which it issues1 through a steel ring1 in the form of a continuous slab1 #f inches #d inches in section1 to a cutter #aj feet distant1 which slices off bricks #aj inches long1 each of which weighs about #aj lbs4 ,the bricks pass to a traveller1 thence by another to feed bins4 ,the briquettes are not dried1 but are used just as made with #ae per cent4 of moisture1 and are generally the last item of the charge to be added on the car4 ,they crumble slightly1 but are sufficiently strong to stand the handling during charging4 ,many similar methods1 including hand processes1 are employed4 7b7 ,sintering ,processes4--,this method of treating fines involves roasting reactions1 as well as the mechanical process of agglomerating4 ,whilst it thus furthers the concentration obtained in the subsequent furnace operation1 since it eliminates some sulphur1 it also utilises the fuel value of the fines1 and yields a product which works well in the blast furnace4 ,several processes have been introduced1 and the ,m#8,murty-,rogers method installed at ,wallaroo1 ,s4 ,australia1 illustrates very well the principles upon which this class of treatment depends4 ,it is a sintering and roasting process similar in type to the ,huntingdon-,heberlein method for lead smelting1 but lime is not used as a rule4 ,it is employed primarily for fine concentrates which are somewhat siliceous4 ,charge4--,must contain #ae to #ce per cent4 silica1 and #ae to #be per cent4 sulphur4 ,pots4--#h feet #f inches in diameter1 when used for ore1 and #d feet #f inches deep2 with vertical sides4 ,there is a false grate #aj inches above the bottom1 pierced with -inch holes4 ,blast4--#a1jjj cubic feet per minute at #ac to #bj ozs4 pressure per square inch4 ,capacity1 #h to #aj tons4 ,time1 #h to #aj hours4 ,method4--,cover the grate with a layer of roasted material1 light small fire of wood1 blow1 and gradually charge in the ore whilst the blast is on4 ,lime is unnecessary1 but water is essential in the process1 and the ore must be very wet2 #f to #i per cent4 water being used for ore charges1 and #c to #d per cent4 with rich mattes1 otherwise working is not uniform1 and the losses by dusting are great4 ,with the requisite quantity of water present1 the working is regular and uniform1 there is little dust1 and the roasting is efficiently performed4 ,products4--,if ore is charged1 a sintered mass of matte and ferrous silicate results2 if poor matte is used1 the product is a rich matte and ferrous silicate2 and if rich matte is used1 metallic copper and ferrous silicate are obtained4 ,at the end of the blow the charge is tipped out and fed into the blast furnace4 ,costs4--,the method as employed at ,wallaroo to treat #djj to #ejj tons of material per week1 operated at a cost of #cs4 #f;d4 per ton1 or about #as4 more per ton than for ordinary roasting4 ,though this particular process is only1 to the author's knowledge1 employed at a few smelters1 sintering or blast-roasting methods on the same principle have been introduced at several other works1 and their adoption promises to lead to very successful results1 being particularly suited for the class of material indicated above4 ,the advantages claimed for the process are that-- 7a7 ,it saves heavy mechanical losses1 such as those of the dust resulting from calcining operations and from the charging of hot calcines into reverberatory furnaces4 7b7 ,it gives a product suitable for blast-furnace smelting--often the cheapest and most convenient method of working4 7c7 ,it results in efficient roasting and good reduction of sulphur1 yields the product in an advantageous form for subsequent smelting1 and promotes a satisfactory removal of impurities in the slag4 ,in addition1 the process offers the possibility in the future of being so modified as to leave in the adequately compacted products so much sulphide that their fuel values can be realised in the blast furnace4 ,in other words1 after the preliminary sintering process1 to smelt the 7fine7 sulphide-concentrates pyritically in the blast furnace4 ,of the more recent types of machine for conducting the process of sintering1 that of ,dwight and ,lloyd is in operation at several smelters4 ,the moistened ore falls on to an endless chain conveyor1 composed of separate grids carried on wheels4 ,the conveyor carries the ore through the flame from a small furnace which starts its ignition1 and it is then drawn over a long suction chamber where air is sucked through the hot mass1 thus effectually roasting and sintering it4 ,the chamber has special devices which ensure the drawing in of the air through the charge only1 and so prevent inward leakage 7see ,fig4 #af74 ,the sintered cakes are finally discharged automatically into cars4 ,details regarding the machine vary at different smelters2 at one works the length is #cj feet1 the rate of travel #h inches per minute1 and the vacuum in the suction chamber #f ozs4 ,the size of the particles should not exceed inch1 and not more than #be per cent4 of the charge should be so large4 ,some #c to #e per cent4 tends to pass through the grids1 and so be drawn into the suction chamber2 this is cleared out at intervals through special doors4 ,water is necessary1 and from #f to #aj per cent4 must be employed in uniformly moistening the charge1 which1 by the addition of suitable fluxes1 is often made of such proportions that in subsequent blast-furnace smelting a satisfactory slag is produced without further additions4 ,the sulphur reduction by the process is very considerable4 ,illustration3 ,fig4 #af4--;,dwight-,lloyd ,sintering ,machine4 ,such blast-roasting methods1 with suitable modifications1 promise to assume considerable importance in the developments of modern smelting practice4 c4 ,roasting4--,roasting is often a very important preliminary stage in the scheme of treatment of copper ores4 ,it was formerly considered an essential operation in smelting processes for sulphide ores1 the material being crushed and concentrated largely with a view to such subsequent treatment4 ,this is not the practice in modern smelting4 ,roasting is now only conducted where the necessity for it arises1 as in the case where wet dressing1 having been considered advisable1 has resulted in the production of large amounts of fine concentrate1 and where reverberatory furnaces are installed for the smelting of this material4 ,preliminary roasting of the concentrates then conduces to the production of a matte of converter grade in one smelting operation4 ,the ,principles of ,copper ,smelting4--,copper extraction from sulphide ores is essentially an oxidation process1 the iron and sulphur being oxidised and the oxide of iron slagged away4 ,all such smelting processes1 both the older and the more modern ones1 are based on this fact1 and underlying all of them are certain fundamental principles which it is essential to keep in mind in considering every phase of the subject4 ,these may be summarised as follows3-- 7#a7 ,in the melting down of a furnace charge1 the copper has first claim on any sulphur which may be present4 7#b7 ,only such sulphur as remains in excess after the copper has been satisfied1 is free to combine with other constituents of the charge4 ,these fundamental principles can best be illustrated by following the reactions during the smelting of a typical charge4 ,thus-- ,copper--- ,cu#b,s-- _/ ,sulphur-- ,cu#b,s4 y,fe,s 444 ,matte4 _/ ,fe,s------ _/ ,iron----- ,fe,o---- _/ ,oxygen--- ,fe,o4 y,si,o#b 444 ,slag4 _/ ,silica ,si,o#b-- ,the copper takes up sufficient sulphur to form ,cu#b,s2 the remaining sulphur combines with any iron which is available1 forming ,fe,s4 ,these two sulphides1 dissolving in all proportions1 constitute the matte product of smelting4 ,the iron in excess of that required by the sulphur becomes oxidised1 and the resulting oxide combines with silica in the charge1 forming the silicate slag of the smelting operation4#e ,it will thus be apparent that1 in general1 the larger the amount of sulphur present in a furnace charge1 the more ,fe,s will there be in the matte after melting1 and the smaller will be the proportion of copper4 ,in consequence1 the grade of the matte will be lower4 ,the proportion of sulphur in the charge thus controls the concentration of the copper by the smelting operation1 and1 in order to effect the desired concentration1 oxygen is required in order to burn off sulphur and to oxidise iron4 ,there are two general methods of supplying this necessary oxygen4 7#a7 ,by a preliminary oxidation of the charge outside the smelting furnace--,roasting4 7#b7 ,by oxidation inside the smelting furnace itself--,the pyritic principle 7to be considered later74 ,modern ,practice as regards ,roasting4--,in modern copper smelting1 the tendency is to do away with roasting as much as possible4 ,objections to ,roasting4--7#a7 ,expense involved by a separate preliminary process4 ,this includes 7a7 ,preparation of the ore for roasting4 7b7 ,extra ground1 and plant required for handling4 7c7 ,labour1 fuel1 etc41 required4 7d7 ,extra handling of material before and after roasting4 7#b7 ,heavy mechanical and other losses during the process4 7#c7 ,loss of the fuel value of the iron and sulphur for smelting4 7#d7 ,necessity1 in the majority of cases1 of having the ore in a fine state of division in order to conduct efficient roasting1 thus militating against its subsequent use in the blast furnace1 unless the product receives preliminary agglomeration4 ,thus at ,tennessee1 the cost of roasting was about #dj cents1 or #as4 #h;d4 per ton of ore 7equivalent to d4 on every pound of copper produced74 ,the cost for the year #aijc amounted to #ai1jjj1 employing #agj men out of a total staff of #ijj at mines and smelters4 ,the conditions for roasting were here exceptionally favourable4 ,the closing of the roast-yards set at liberty #cd1jjj1 which had been tied up in this manner4 ,advantages of ,roasting4--,illustrative of the conditions under which roasting is advantageously conducted in modern practice1 the case of the ,butte second-class ores may be quoted4 ,these ores contain about #e per cent4 of copper in the form of sulphides1 finely disseminated through large quantities of siliceous gangue4 ,direct smelting in a blast furnace would not yield a matte of the desired 8converter0 grade1 except at very heavy expense and difficulty4 ,the ore is1 therefore1 wet-dressed up to #i to #aj per cent4 copper1 and the coarse concentrates now help to yield a good matte1 when smelted in the blast furnace4 ,by the wet-dressing treatment1 however1 a considerable quantity of fine material is unavoidably produced1 for which the most convenient treatment in such large quantities1 under prevailing conditions1 is in the reverberatory furnace4 ,the atmosphere of this type of furnace being to a great extent neutral1 the charge would tend simply to melt down without very much reduction of sulphur1 resulting in the production of very low-grade matte4 ,roasting of these fine concentrates is1 therefore1 desirable for reducing the sulphur to such an extent as will yield a high-grade converter matte4#f ,roasting being thus often advisable as a preliminary1 its inclusion in a smelting scheme under suitable conditions entails the following advantages over the direct reverberatory treatment of unroasted ores3-- 7#a7 ,it ensures satisfactory concentration on smelting4 7#b7 ,it leaves reverberatory furnace smelting practically a remelting operation1 and so affords exact control of the concentration effected4 7#c7 ,the roaster gases may be utilised for making acid4 ,in modern practice the work of the reverberatory plant is controlled at the roasters4 ,the reverberatory foreman smelts whatever mixture is sent from the roasting plant1 and if the grade of the resulting matte is not satisfactory1 it is in the roasting operations that the required change is made for the correct adjustment of the sulphur and for controlling the consequent tenor of the matte4 ,the ,reactions of ,roasting4--,the operation of roasting is the exposing of a substance to the effects of heat and air1 in order to oxidise it1 and to render it more suitable for subsequent smelting operations4#g ,in the case of the ordinary sulphide copper ores1 roasting not only 7a7 reduces sulphur1 and so ensures good concentration on smelting1 but 7b7 by oxidising the iron1 provides a ready flux for siliceous gangues4 ,the more important reactions occurring to the usual constituents of the copper ores which are roasted1 may be summarised as follows3-- ,iron ,pyrites4--,first loses free sulphur at a low temperature3 it is generally assumed that ,fe,s is left1 but the residual sulphide rarely attains this composition-- ,fe,s#b ,fe,s ,s4 ,iron ,sulphide4--,sulphur has a great affinity for oxygen1 to form ,,so#b and it may be assumed that this reaction first takes place thus-- ,fe,s ,o#b 7,fe7 ,,so#b 7i47 ,the iron is however instantly oxidised by the excess oxygen always present-- 7,fe7 ,o ,fe,o 787 7ii47 ,or1 combining 7i47 and 7ii47-- ,fe,s #c1,o ,fe,o ,,so#b4 ,this sulphur oxidation is an important source of heat1 and in the early stages of roasting1 sulphur is seen burning with the familiar blue flame1 and the mass becomes red hot2 stirring being required to prevent the material from sintering by the heat generated within itself4 ,the oxidation of the iron generally proceeds further1 yielding higher and more stable oxides-- #b;,fe,o ,o ,fe#b,o#c4 #c;,fe,o ,o ,fe#c,o#d4 ,the ,,so#b in the presence of oxygen and in contact with strongly heated material further tends to form ,,so#c1 which is a powerful oxidising agent1 and plays a considerable part in the various oxidising reactions which occur4 ,pyrrhottite behaves in much the same way2 it may be regarded as consisting of x,fe,s a little extra sulphur4 ,it does not roast quite so easily as pyrites1 partly on account of physical characteristics1 and partly because1 in the case of pyrites1 the greater amount of excess sulphur which is first driven off1 tends to leave the mass more porous and so assists oxidation4 ,copper ,sulphide4--,its characteristics on oxidation have already been indicated in ,lecture ,,iii41 p4 #cf4 ,it melts easily1 often at roasting temperatures1 hence careful heating and attention are required when much is present4 ,the reactions are probably analogous to those of ,fe,s oxidation1 in the primary oxidation of the sulphur and the instantaneous oxidation of the nascent copper-- ,cu#b,s ,o#b 7#b;,cu7 ,,so#b 7#b;,cu7 ,o ,cu#b,o1 thus ,cu#b,s #c4,o ,cu#b,o ,,so#b2 this being accompanied by simultaneous action of the following nature3-- ,cu#b,o ,,so#b #b1,o #b;,cu,o ,,so#c ,cu,o ,,so#c ,cu,s,o#d ,cu,s,o#d ,cu#b,o #c;,cu,o ,,so#b4 ,in addition to the tendency to melt1 copper sulphide roasts less perfectly than the ,fe,s1 usually yielding oxides which are accompanied by small quantities of sulphate4 ,chalcopyrite is the commonest copper ore1 and the material most frequently subjected to roasting in copper smelting practice4 ,consisting of ,cu#b,s4 ,fe#b,s#c1 and accompanied usually by a large excess of ,fe,s#b1 it behaves very much like a mixture of these sulphides when treated in the roaster furnace1 hence the reactions on roasting follow on the lines just indicated4 ,in practice the roasting is never carried to such a degree that all the sulphur is eliminated1 since it is essential to retain some sulphur in order to collect the copper in the form of matte1 and also because the time1 and the cost of the fuel required to roast all of it off1 would be prohibitive4 ,consequently1 the products from the roasting of chalcopyrite consist principally of oxides of iron and copper1 together with a certain amount of copper sulphate1 very little iron sulphate1 and some undecomposed sulphides4 ,the actual form in which the sulphur is present at the end of the roasting operation is not usually of very special importance in practice1 especially where the previous experience with the roasted material determines the extent to which the roasting is conducted1 since the greater part of the sulphur eventually produces the sulphide and constitutes the matte1 on smelting the roasted charge2 although some is also eliminated as ,,so#b by interaction with oxides4 ,in modern roasting practice1 therefore1 all that is usually required is to roast the ore down to1 say1 #e per cent41 #f per cent41 #h per cent41 or whatever proportion of sulphur is necessary to yield the required grade of converter-matte in the reverberatories1 as judged by previous experience of the furnace plant and working4 ,much ,,so#b is evolved during the roasting1 though it is usually largely diluted with nitrogen from the air used up4 ,other ,foreign ,constituents of ,copper ,ores--,zinc ,sulphide4--,zn,s is sometimes present4 ,some remains unchanged on roasting1 as the heat in ordinary practice is not great enough to thoroughly decompose it4 ,some oxide and some sulphate are also produced4 #b,zn,s #g1,o ,zn,o ,zn,s,o#d ,,so#b is suggested by ,peters as a probable reaction occurring to this material under roasting conditions4 ,lead ,sulphide is also occasionally present with copper ores4 ,it melts readily1 and is not entirely decomposed at the temperatures employed for the roasting of copper ores4 ,the reactions on oxidation are largely analogous to those for other sulphides4 ,pb,s ,o#b ,pb ,,so#b ,pb ,o ,pb,o or1 ,pb,s #c4,o ,pb,o ,,so#b4 ,also1 #b,pb,o ,,so#c ,pb,s,o#d4,pb,o 7basic sulphate74 ,arsenides are partly left as the corresponding oxides1 whilst some ,as#d,o#f is evolved1 and some basic arsenate generally remains4 ,roasting ,practice4 ,favourable ,conditions for ,successful ,roasting4 7a7 ,the sulphide should be in a finely divided form1 so as to ensure good contact with the air4 7b7 ,the air should be supplied in a gentle current1 so as to continually provide fresh oxygen1 and sweep away the inert gases which are produced4 7c7 ,the ore should be heated to a dull red heat1 which is a condition favourable for commencing the ignition and reactions4 ,the temperature should1 of course1 be well below a melting heat 7,peters74 ,the ,apparatus for ,roasting depends to some extent on the class of material to be dealt with1 which may be in the form of either 7a7 lump ores1 or 7b7 fine ores4 7a7 ,roasting of ,lump ,ores4--,in modern copper-smelting work1 the practice of roasting lump ores is practically obsolete4 ,the conditions under which its use might still be justified are those associated with newer mining districts1 where rapid concentration of heavy sulphide ore into matte is required1 before the time is ripe for smelting the material pyritically1 and where further1 it is desired to employ the blast furnace for the smelting operations under these circumstances4 ,the advantages possessed by the method are-- 7#a7 ,no preliminary crushing is required4 7#b7 ,the product is largely in the form of lumps1 and hence immediately suitable for blast-furnace work4 7#c7 ,the plant and appliances required are simple4 ,the two methods employed are--7,a7 open-air roasting1 7,b7 roasting in kilns4 ,a4 ,open-air ,roasting of ,lump ,ores4--,this method is conducted in heaps or stalls1 and the features just considered apply particularly to this branch of roasting practice4 ,the modern tendency is to avoid heap-roasting altogether1 and it is only conducted when the conditions are exceptional4 ,amongst the many grave objections to open-air roasting are-- 7a7 ,it is very slow1 since a long period of time is required for the oxidising effect to penetrate through massive lumps of ore4 7b7 ,a large amount of capital is tied up in the material at the roast-yards4 7c7 ,the losses occasioned by wind and rain are very considerable4 7d7 ,it is difficult to use up a large quantity of fines in the roast-heaps4 7e7 ,difficulties arise owing to damage by the fume1 and from interference by litigation4 ,there is one special instance of a modern smelter making a great success of heap-roasting--namely1 at ,rio ,tinto--but the circumstances are peculiar1 as the roasting is followed by leaching operations of the immense ore heaps in situ4 ,this branch of roasting need not be considered at length1 and the older standard text-books give full descriptions of the various methods employed4 ,the following particulars are important1 however1 when under exceptional circumstances such work has to be undertaken3-- ,the maximum and best average size under ordinary conditions is #dj feet by #bd feet1 by #g feet high above the bed of fuel4 ,the height is important1 and varies with the quantity of sulphur in the ore4 ,the lower the sulphur content1 the higher the pile2 with about #dj per cent4 sulphur1 the best height is #f to #g feet2 with #ae per cent4 of sulphur1 up to #i feet2 and if still less sulphur be present1 the height may even be a little greater4 ,such a heap holds about #bdj tons1 and if the quantity of ore to be dealt with exceeds this1 a number of such piles should be constructed4 ,the time occupied in roasting is about #gj days1 with #aj days more for removing and rebuilding4 ,the selection of a proper site is important4 7a7 ,the prevailing direction of the wind must be considered1 so as to keep the fumes away from the works and offices4 7b7 ,the yards must be protected from winds1 so as to prevent losses of dust1 as well as uneven burning4 7c7 ,the ground must be perfectly dry or drained4 ,along the upper edges of the roast-yard a deep trench should be cut1 so as to catch rain-water1 and prevent it from washing soluble copper salts out of the pile2 drainage trenches must also be provided to carry any copper-bearing liquors to some point where the copper can conveniently be precipitated on scrap iron4 ,enormous losses of copper may occur if these precautions are not observed2 thus1 at one period in the old roasting process in ,tennessee1 as much as #cd per cent4 of the copper in the heaps was lost in #ahf days4 ,preparing of the ,floor4--,remove roots and subsoil1 fill space with broken stone or rough tailings1 cover with #d to #f inches of clayey loam1 and beat down well4 ,the floor is then fairly impervious1 and does not crack on drying4 ,the ground should be given a gentle slope so as to facilitate draining4 ,a layer 7about #f inches thick7 of fine ore is next put down1 then #i inches of fuel2 channels are now mapped out by means of logs set in both directions1 leading to rough chimneys4 ,the pile is then constructed1 with the lower parts of the very coarse materials1 smaller stuff being put towards the top and sides4 ,on the very top and at the outside of the pile are placed the fines1 but this top cover is only put on when the burning is well started4 ,this process is still worked at ,tyee1 ,b4,c41 and at some other localities1 but is most probably only a temporary plan1 to be replaced by a more efficient method as development progresses4 ,b4 ,kilns for ,lump ,ores4--,kilns possess the advantage that they permit of arrangements being made for the recovery of ,,so#b for acid manufacture1 and the subject belongs more properly to that branch of technology4 ,few large smelting works employ kilns for roasting lump ores1 though there are important exceptions at works both in ,britain and on the ,continent of ,europe4 ,kilns are used at the ,cape ,copper ,company's smelter at ,britton ,ferry1 for this purpose4 7b7 ,the ,roasting of ,fines4--,fines 7and particularly fine concentrates7 are the usual materials subjected to roasting4 ,the finer the particles1 the more rapid and complete is the oxidation1 but the losses by dust are heavier4 ,the size limit is thus liable to some variation1 but often the material roasted is that under -inch in size4 ,roasting ,furnaces--,requirements4--,for the roasting of fines there is simply required a place where the material can be gently heated in the presence of a constantly renewed air supply4 ,the fuel has itself a reducing action1 it must therefore be separated from the charge1 and hence the furnace employed is of the reverberatory type4 ,muffles are never used for the oxidising roasting of copper ores4 ,since only a moderate temperature is necessary for the operation1 the furnace needs but a small fireplace1 and it is provided with a large hearth area4 ,the fuel used is one yielding the fairly long oxidising flame required4 ,developments of ,roasting ,practice4--,the main objects sought in roasting practice have been-- 7#a7 ,to have as large a surface of material exposed to heat and air as possible4 7a7 ,by elongating and multiplying the beds of the furnace4 7b7 ,by furrowing and rabbling the charge4 7#b7 ,continually to expose fresh surfaces of ore to oxidation4 7a7 ,first by hand-rabbling4 7b7 ,later by movable furnace hearths4 7c7 ,by mechanical rabbling4 7#c7 ,to obtain a continuous output-- 7a7 ,by mechanical charging1 rabbling1 and discharging4 ,the ,development of the ,roasting ,furnace4 ,a4 ,,fixed ,,hearth4--,in ,great ,britain from #aehc onward1 roasting in small reverberatory furnaces seems to have been the usual method1 and up to #ahej the furnaces appear to have been only of moderate dimensions1 with a single hearth1 #af feet #ac feet #f inches1 constructed of firebricks set on end1 and with a fire-box #g feet #b feet #c inches #ah inches4 ,rabbling was done by a long rake1 the material being charged and worked through one door4 ,this method of working wasted time1 made the process intermittent1 and caused continual cooling down of the furnace1 involving large fuel costs and much labour4 ,the first improvements were to lengthen the hearth1 to add more working doors1 and to put the charge into the furnace by a hopper passing through the roof4 ,it was next found best to elongate the hearth still further1 and to drop the level of the bed in stages by about #b inches at a time1 thus ensuring better control of working4 ,by this means the best type of hand-calciner was arrived at1 consisting of four beds1 each #af feet #af feet1 the whole charge being moved forward from one bed to the next at each stage of the process4 ,in roasting1 the ore is first placed in the coolest part of the furnace1 and is worked towards the fire1 so that the charge travels in one direction1 and the flame and furnace gases in the opposite direction to meet it4 ,the advantages of this system are that-- 7a7 ,the clotting of the sulphides is prevented1 since the first part of the roasting proceeds at a comparatively very low temperature4 7b7 ,the sulphur in the ore often provides sufficient heat to maintain the roasting in progress during the early stages4 7c7 ,the hottest parts of the furnace are where the roasted infusible oxides arrive1 so but little clotting or sintering occurs here4 ,the capacity of the four-bedded hand-roaster is #g to #ae tons per twenty-four hours1 depending on the sulphur proportion in the charge and in the roasted product4 ,it is a very useful form of furnace when labour is cheap4 ,the furnace works very efficiently1 but in the ,new ,world1 where manual labour was dear1 labour costs became prohibitive1 and in order to economise in this direction1 mechanical rabbling was introduced4 ,the ,o',harra ,calciner 7#ahhe7 was essentially the old type of furnace1 double hearthed and mechanically rabbled4 ,it consisted of long straight furnace hearths4 ,the rabbles were ploughs dragged through the furnace by means of endless chains which were carried over grooved pulleys1 situated outside the furnace1 at the ends4 ,this was an important invention1 giving a continuous feed and discharge1 a much larger output1 and efficient and regular stirring without much hand labour4 ,the rabbles became cooled on issuing from the hearth4 ,the capacity was #ej tons per day from furnaces of #ij feet #i feet hearths1 giving a roasting capacity of #fa lbs4 of ore per square foot of hearth area1 compared with about #cc lbs4 per square foot with the old hand calciner4 ,in working the early forms of this furnace there were many mechanical troubles and breakdowns1 and the subsequent modifications of this form consisted largely of devices for the purpose of overcoming such difficulties4 ,modifications and ,improvements4--,allen1 instead of a rope to carry the ploughs1 used small wheeled carriages1 running on a track which was laid along the floor4 ,brown 7important7 ran the carriages along narrow corridors at either side of the hearth1 so as to protect the ropes and carriages from the very corrosive action of the furnace gases4 ,a continuous narrow slit along the inner wall of the corridors allowed the arm carrying the plough to travel forward4 ,wethey2 ,keller2 worked on very similar principles4 ,the chief improvements were in details1 and had for their object the prevention of wear and tear1 and of the break-down of parts4 ,prosser4--,very similar2 used at ,swansea ,works4 ,ropp4--,the carriage runs underneath the bed1 and supports a vertical shaft which passes through a slot along the furnace hearth and carries the arms furnished with ploughs4 ,illustration3 ,fig4 #ag4--,o',harra ,furnace 7,fraser-,chalmers71 illustrating ,principle of ,mechanical ,rabbling by ,travelling ,ploughs4 ,the ,ropp and ,prosser calciners work very successfully4 ,the hearth is about #aje feet long #aa feet wide1 with a capacity of about #cf tons per day4 ,illustration3 ,fig4 #ah4--,section through ,mechanically ,rabbled ,roaster ,furnace 7illustrating ,improvements for ,protecting ,driving ,mechanism74 ,brown ,horse-,shoe ,furnace operates on the same principle as the above1 except that the hearth is bent round in order to save space4 ,pearse-,turrett 7#ahib at ,argo74--,in this type of furnace the bed is curved round in the form of a circle4 ,the rabbling ploughs are carried at the ends of arms which are attached to an upright rotating spindle4 ,the spindle is set in the centre of the space enclosed by the circular hearth4 ,in all the above classes of furnace1 the firing is done1 when necessary1 from fireplaces built at intervals along the sides of the furnace2 either coal or gas being employed as fuel4 ,b4 ,,rotating ,,hearths4--,this type of furnace is still reverberatory1 but instead of making use of mechanical rabbling1 the hearth rotates1 in order to give agitation to the materials and assist their discharge4 7a7 ,intermittent ,working--,the ,brckner ,roaster4--,the details and working of this roaster are familiar4 ,the furnace was invented in #ahfd for gold and silver ore-roasting in ,colorado1 and was later introduced for the roasting of copper ores1 being at one time the furnace most commonly used for the purpose4 ,it was employed all over the ,western ,states1 and at one works alone1 #ef were at one time in use4 ,the usual length was #ah feet #f inches and the diameter1 #h feet #f inches2 giving an output of about #ab tons per twenty-four hours4 ,it was furnished with a removable fireplace1 used to start the roasting4 ,the operation could then be allowed to proceed by itself1 the fireplace being wheeled away to another hearth1 and being eventually brought back to the first hearth for about three hours1 in order to give the required higher finishing temperature4 ,several dust chambers were attached to this1 as to all forms of roasting furnaces1 which by their nature and manner of work are apt to produce considerable quantities of dust4 ,the advantages of the ,brckner cylinder lay largely in the fact that it afforded good control of the sulphur contents in the charge1 since the ore could be retained in the furnace until the sulphur was sufficiently low4 ,the furnace is simple to work1 and not so liable to get out of order as many other forms4 ,it possesses however1 distinct disadvantages in that its working is intermittent1 its use involves comparatively high fuel costs1 whilst the discharging presents considerable difficulty and trouble to the labour employed1 on account of the awkwardness and the high temperature of the discharge1 and the sulphurous gases evolved4 ,its use has now been very largely discontinued4 ,improvements--7b7 ,continuous ,working4--,the continuous type of roasting furnace of this class involves the use of sloping cylindrical hearths which rotate1 and so agitate and help to discharge the materials4 ,oxland 7#ahfh7 first introduced this type in ,cornwall1 for the roasting of tin ores4 ,the ,oxland furnace was an inclined cylinder1 the material was fed in at the top1 and by the rotation of the cylinder the charge gradually travelled downwards1 approaching nearer and nearer to the fire1 and being discharged close to the fire-box4 ,white 7#ahgb7 improved this furnace1 and the ,white cylinder is largely used in ,south ,wales4 ,the cylinder revolves slowly by friction gearing2 inside are four lines of projecting brick-work which form a shelf1 thus assisting the agitation of the charge4 ,the ,white-,howell ,furnace is somewhat similar to the ,white1 but is unlined for the greater part of its length1 except at the lower end near the fire-box1 where it is much wider and is bricked4 ,it is stated to work more satisfactorily than the older form1 having a larger capacity and using but little fuel4 ,the furnace is employed at the ,cape ,copper ,works1 ,south ,wales1 for matte-roasting4 ,it is here #fj feet long1 #g feet diameter1 inclined #f inches in #fj feet1 makes #h revolutions per hour1 and has a capacity of #aj tons of charge per day4 ,argall ,furnace4--,consists essentially of four narrow tubes bound together1 each #bh feet long1 #b feet diameter1 and lined4 ,it works rapidly1 having a capacity of #dj to #ej tons per day1 but is used more for the roasting of cupriferous gold ores than at the copper smelters4 ,c4 ,,the ,,macdougal ,,type4--,the most important form of modern roaster furnace1 and that most generally employed1 is the ,mac,dougal type4 ,the first furnace on this principle was invented by ,parkes in #ahfj4 ,the design embodied two hearths1 one above the other4 ,vertically down the centre of these passed a spindle1 supporting arms from which were suspended the ploughs1 and the rotation of this spindle carried the arms over the beds4 ,as devised by ,parkes1 various mechanical difficulties were found1 and the working was intermittent1 but the principle was recognised as important4 ,mac,dougal in #ahgc introduced his modification of the furnace1 primarily for the roasting of pyrites1 at a ,liverpool works1 and this form has now supplanted many of the older types for copper ore roasting1 and is in operation at most of the new smelting works4 ,principles of the ,mac,dougal ,type4--,the furnace consists of an iron cylinder lined with brick4 ,six circular hearths are constructed inside1 one above the other1 and the vertical spindle carrying the arms and ploughs for each hearth passes through the centre of the furnace4 ,the ore is ploughed towards openings on each hearth1 which communicate with the hearth below2 the charge thus travelling from the outer edge towards the centre1 through the central opening to the middle of the next floor1 then outwards to the openings at the edge1 and so on4 ,the original ,mac,dougal furnace was #ab feet high and #f feet in diameter4 ,it was improved by ,herreshof in the direction of better rabbling mechanism and greater ease of repair4 ,the central spindle was an air-cooled shaft1 the supporting arms were made so as to be easily removable from the shaft to facilitate repairs1 and the furnace was enlarged4 ,herreshof used air-cooling for the spindle and arms1 as shown in ,fig4 #bj4 ,illustration3 ,fig4 #ai4--,mac,dougal ,roaster--,vertical ,section4 ,illustration3 ,fig4 #bj4--;,herreshof ,furnace--,section indicating ,connections for cooling ,rabbles and ,spindles4 ,evans1 and subsequently ,klepetko1 in working the furnaces in ,montana1 introduced1 in about #ahib1 various marked improvements4 ,the dimensions were increased1 enlarging the output4 ,the spindle and arms were water-cooled1 which improvement removed much of the great difficulty in working the ,mac,dougal furnace1 where the rapid wearing out of working parts1 and the difficulty of their removal1 repair1 and renewal interfered greatly with efficient working4 ,many of these troubles have now been overcome in the ,evans-,klepetko type1 and in the still further improvements since made at ,anaconda4 ,the general arrangement of the floors1 spindles1 arms and other details shown in the ,herreshof furnace 7,fig4 #bj7 are preserved in the ,evans-,klepetko and similar types of roaster2 the chief alterations are in matters of detail1 the results of which have however1 been important4 ,furnaces of this improved kind are now used all over the ,west2 there are #fd at ,anaconda1 ,mont42 #cb at the ,international ,smelter1 ,tooele1 ,utah2 #bd at ,garfield1 ,utah2 #af at ,steptoe1 ,nevada2 and also at ,balakala1 ,cal41 ,cerro de ,pasco1 ,peru1 and other large smelting centres4 ,important ,advantages4--,of the marked advantages of this type of furnace1 the following are perhaps the most striking and important3-- 7#a7 ,there is a great saving of floor space by having the six hearths one above the other4 7#b7 ,the use of a central common spindle carrying the arms and ploughs simplifies the mechanism4 7#c7 ,the form is convenient for the compact arrangement of a roasting plant of many units for feeding1 discharge1 and supervision4 7#d7 ,very little heat is lost by radiation1 as the heat passes mostly from one hearth to another4 7#e7 ,very little fuel is required1 none with heavy sulphides 7except for starting71 as the heat of oxidation of the iron and sulphur usually yields a high enough temperature to keep the operation going4 ,the fuel costs are lower than in other types of roaster4 7#f7 ,thorough rabbling1 greater uniformity and better mixing of product1 continuous and regular feed and discharge are obtained4 7#g7 ,the roasting is thorough1 and perfect control of the degree of oxidation is ensured by adjusting the rate of passage of the ore through the furnace1 which is regulated by varying the ore feed and the speed of rotation of the rabbles4 7#h7 ,great saving in labour costs and difficulties4 ,the labour in roasting plants is extremely arduous1 on account of the high temperature of the material1 and is dangerous on account of the atmosphere4 ,the ,evans-,klepetko-,mac,dougal ,roasting ,furnace ,plant at ,anaconda4--,the roasting plant at ,anaconda formerly consisted of #ef ,brckner cylinders1 which were eventually all scrapped and replaced by new plant of the ,mac,dougal type1 subsequently greatly modified and improved as one difficulty after another had to be overcome4 ,the saving in working costs resulting from this replacement of the ,brckners by ,mac,dougal roasters is reckoned at about #e cents 7#b;d47 on every ton of calcines treated4 ,the roasters are arranged in four rows of #af each1 running east and west4 ,the charge cars travel along tracks at a height of #bj feet above1 discharging into rows of bins1 one situated over each calciner4 ,illustration3 ,fig4 #ba4--,spindle ,connections and ,guide ,shields of ,evans-,klepetko ,roasters4 ,details of ,furnace4--,height1 #ah feet #c inches2 diameter1 #af feet4 ,six hearths4 ,the spindle is made in three lengths1 each to carry the arms for two hearths2 it is #ah inches in diameter and is water-cooled4 ,the rabble arms are #f feet long1 half round1 and flanged on the lower side2 they too1 are hollow and water-cooled4 ,the rabble-blades were formerly cast in one piece with base plate1 so as to slide on to the arms1 but are made now with detachable blades1 which slide into grooves on the base plate1 so as to facilitate removal for repairs2 the blades are #f inches square and #a inches thick 7,fig4 #cb74 ,the arms on separate floors are set alternately at right angles4 ,of the two arms for each floor1 one carries six blades1 the other seven1 so that the furrows resulting from one set of blades are turned over by the other4 ,the blades are set so as to direct the ore from the outer to the inner edge or vice vers1 according to the particular hearth4 ,the spindle and connections are protected from falling ore by shields which are bolted on4 ,the rabbles move slowly1 making a #b-;inch furrow in a #e-;inch layer of material4 ,capacity4--#dj to #de tons per day each1 reducing the sulphur in the charge from #cj per cent4 to about #hj per cent4 ,the output of the plant is about #c1jjj tons of calcines daily4 ,system of ,working4--,since reverberatory furnaces are used essentially as remelting furnaces only1 the roasting plant is operated so as to yield a product of such composition as will directly produce a suitable matte and slag on melting in the reverberatories4 ,the fluxes required for the calculated reverberatory charge are1 therefore1 sent through the roasters mixed with the fine concentrate2 such practice possessing many advantages4 ,the charge thus consists of fine concentrate from the concentrator settling tanks1 and screened lime-rock flux 7too fine to be used in the blast furnaces74 ,the limestone lightens the charge1 decreases the tendency to clotting of the pure sulphides1 chemically assists oxidation1 preheats and thoroughly mixes the flux1 and ensures a uniformly mixed charge for the reverberatory furnaces2 whilst the extra cost involved is but very small4 ,three per cent4 of lime is used2 #dj tons of concentrates1 #a tons of lime-rock1 and #a tons of flue-dust being charged per twenty-four hours per furnace1 through an automatic gravity feed1 the opening of which is closed and opened by an eccentric4 ,the speed of the eccentric and the extent of the opening are adjustable4 ,working4--,charge contains #be to #ce per cent4 sulphur4 ,illustration3 ,fig4 #bb4--,rabble-blades and ,bases4 #ast ,hearth4--,temperature about #bcj ,c4 7black heat74 ,this is practically a drying floor1 and the wet ore wears the rabbles away rather quickly4 ,special forms of plough are being introduced4 ,about #d per cent4 of sulphur is driven off from the pyrites4 #bnd ,hearth4--,hotter2 not quite red1 except near outer edge4 ,about #e per cent4 of sulphur burnt off4 #crd ,hearth4--,bright red heat 7about #gjj ,c474 ,sulphur can be seen burning off the ridges of calcines1 with a blue flame4 #e per cent4 of sulphur eliminated4 ,there is some clotting1 and the sinter sticks to the rabble-blades1 and has to be barred off occasionally4 #dth ,hearth4--,bright red heat 7about #gej ,c471 uniformly bright1 but the flame has ceased4 ,sulphur loss1 #d per cent4 #eth ,hearth4--,the hottest 7#hjj ,c474 ,bright red4 ,bottom ,hearth4--,cooler1 dark red 7about #fej ,c474 ,the doors on this floor are left open4 ,the charge is guided towards openings at the outer edge to discharge chutes whilst still red hot1 and it is fed from here whilst hot into the reverberatory furnace-bins4 ,efficient dust catchers and settlers are essential on the roasting plant4 ,the gases escaping at a temperature of about #cae ,c4 contain #b per cent4 of ,,so#b by volume1 #e per cent4 by weight4 ,the ore takes #b hours to pass through the furnace4 ,practically no fuel is required except to warm up the roaster on commencing work4 ,labour4--,the requirements are small4 ,there is one general foreman for the plant1 and two helpers for each set of four furnaces4 ,the conditions are rather trying1 especially during the discharge of the calcines into the reverberatory charge cars4 ,,roasting ,,ores ,,poorer ,,in ,,sulphur1 ,,in ,,macdougal ,,roasters4--,the ,anaconda concentrates carry sufficient sulphur 7#cc per cent47 to supply all the heat necessary for carrying out the roasting operations4 ,when the sulphur is below this requisite quantity1 some extra heating may be required1 though1 on the other hand1 the reduction which is necessary in the sulphur contents is lessened1 depending1 of course1 on the proportions of copper and iron in the charge4 ,at ,garfield1 ,utah1 where the concentrate only contains #bj per cent4 of sulphur1 the fuel required for all roaster purposes is equivalent to #jb per cent4 of the charge1 one of the calcines' outlets being converted into a fireplace4 ,here the output per furnace per day approaches #ee tons1 roasting the sulphur from #bj per cent4 down to #aj to #aa per cent4 ,the flue-dust losses at this plant are #f per cent41 so efficient dust catching appliances are essential4 ,the ,costs of ,roasting in the ,mac,dougal ,furnace4--,ricketts has recently published a valuable analysis of the costs of the roasting operations at the ,cananea ,smelter4 ,the figures must1 however1 be understood to apply strictly to the conditions prevailing at this particular camp4 ,the roaster plant consists of #cb improved ,mac,dougal furnaces4 ,the charge supplied to the roasters assays-- ,copper1 #eb per cent4 ,iron1 #bhd ,sulphur1 #bii ,silica1 #bcf ,alumina1 #cg whilst the product 78calcines07 has an average composition of ,copper1 #fc per cent4 ,iron1 #cde ,sulphur1 #gg ,silica1 #bhf ,alumina1 #dd ,the plant operated on the following quantities of material1 from ,february to ,july1 #aiaa1 inclusive3-- ,concentrates1 #cb1ibi short tons #gfjh per cent4 of charge4 ,fine sulphide ores1 #i1eij #bbaf ,limestone1 #gfb #agf ------------ ------------ ,total charge1 #dc1bha #ajjjj ,weight of 8calcines0 produced1 #ce1ecc #hbaj ------------ ------------ ,shrinkage1 #g1gdh #agij ,the total costs of roasting 7from roaster charge-bins to reverberatory furnace7 worked out at #chde cents per ton1 the distribution of these costs being as follows3-- ,total ,costs4 ,cost per ,dry ,ton4 ,sampling1 #bbbfb #jjjea ,bedding1 #b1jafbg #jjdff ,reclaiming1 #c1jgbga #jjgaj ,operating furnaces1 #g1fhjeh #jagge ,hauling calcines1 #iaaja #jjbaj ,general expenses1 #a1fciii #jjcgi ---------------- ------------- ,total direct costs1 #ae1edcch #jceia ,cost of flux1 #a1jighe #jjbed ---------------- ------------- ,total costs1 #af1fdabc #jchde ,,analysis ,,of ,,cost-- 7#a7 ,operating-- ,labour1 #g1cihef #jagji ,power1 #a1eggfd #jjcfe ,fuel1 #ggcjh #jjagi ,water1 #ghga #jjjah ,sundries1 #ajcj #jjjjb ,flux1 #a1jighe #jjbed -------------------- ----------------- #aj1icfad #jbebg 7#b7 ,repairs-- ,labour1 #b1ejgce #jjegi ,shop expense1 #cfajj #jjjhc ,supplies1 #b1hcfgd #jjfef ------------------- ------------- ,total costs1 #af1fdabc #jchde ,references4 ,peters1 ,e4 ,d41 8,principles0 and 8,practice of ,modern ,copper ,smelting40 ,cloud1 ,t4 ,c41 8,the ,m#8,murty-,rogers ,process for ,desulphurising ,copper ,ores40 ,trans4 ,inst4 ,min4 and ,met41 vol4 xvi41 #aijf-g1 p4 #caa4 ,hofman1 ,h4 ,o41 8,recent ,progress in ,blast ,roasting40 ,bulletin ,amer4 ,inst4 ,min4 ,eng41 ,no4 #db1 ,june1 #aiaj4 ,austin1 ,l4 ,s41 8,the ,washoe ,plant of the ,anaconda ,copper ,mining ,company40 ,trans4 ,amer4 ,inst4 ,min4 ,eng41 vol4 xxxviii41 #aijf1 p4 #efj4 ,rickets1 ,l4 ,d41 8,developments in ,cananea ,practice40 ,engineering and ,mining ,journal1 ,oct4 #gth1 #aiaa1 p4 #fic4 ,redick ,f4 ,moore1 8,recent ,reverberatory ,smelting ,practice40 ,engineering and ,mining ,journal1 ,may #adth1 #aiaj1 p4 #ajba4 ,see also-- ,pulsifer1 ,h4 ,b41 8,important ,factors in ,blast ,roasting40 ,met4 and ,chem4 ,eng41 #aiab1 vol4 x41 ,no4 #c1 ,march1 pp4 #aec-aei4 7,with good ,bibliography47 ,editorial ,correspondence1 8,sinter-,roasting with ,dwight-,lloyd ,machines at ,salida1 ,col40 ,ibid41 #aiab1 vol4 x41 ,no4 #b1 ,feb41 p4 #hg4 ,dwight1 ,a4 ,s41 8,efficiency in ,ore-,roasting40 ,school of ,mines ,quarterly1 #aiaa1 vol4 xxxiii41 ,no4 #a1 ,nov41 pp4 #a-ag4 ,,lecture ,v4 ,,reverberatory ,,smelting ,,practice4 ,functions of the ,reverberatory ,furnace -- ,requirements for ,successful ,working -- ,principles of ,modern ,reverberatory ,practice -- ,operation of ,modern ,large ,furnaces -- ,fuels for ,reverberatory ,work2 ,oil ,fuel2 ,analysis of ,costs -- ,condition of the ,charge4 ,the ,functions of the ,reverberatory ,furnace4--,the reverberatory is essentially the furnace for the smelting of fine material1 as the comparatively still atmosphere1 the absence of blast1 and the opportunities for settling prevent the heavy losses by dust which necessarily accrue with the other types of smelting furnace4 ,the atmosphere of the furnace is practically neutral1 it therefore exercises little influence on the reactions taking place in the charge1 and the reverberatory is1 in consequence1 mainly a melting furnace4 ,its functions are3-- 7a7 ,to allow of the formation1 from the mixture of sulphides and oxides in the roasted materials from the calciners1 of a copper matte and a slag4 7b7 ,to maintain such a high temperature as to render these products perfectly fluid1 and thus to allow the matte and slag to settle and separate thoroughly4 ,in spite of the neutral atmosphere1 however1 the smelting of the roasted materials usually results in a higher concentration than would be expected from the calculation of the sulphur1 copper1 and iron in the charge4 ,the reason of this is that the smelting operation results in some further elimination of the sulphur1 which causes the production of a higher grade matte4 ,this additional elimination of sulphur in the reverberatory furnace smelting of the roasted charge is due to the reactions which take place on melting1 between the oxides1 sulphates1 and sulphides of copper1 all of which exist in the products from the roasters4 ,these reactions are expressed by the equations-- ,cu#b,s #b;,cu#b,o #f;,cu ,,so#b ,cu#b,s ,cu,s,o#d #c;,cu #b,,so#b1 which indicate a further addition of copper to the matte1 and a corresponding loss of sulphur4 ,thus a typical reverberatory charge of the following composition3-- ,silica1 #bgb per cent4 ,iron1 #caj ,lime1 #bc ,sulphur1 #hd ,copper1 #hc should theoretically yield1 on melting down1 a matte running-- #h;,cu 7#hc7 - ,cu#b,s #ajd ,cu #hc ,cu #cj ,s #hd or ,s #cj ,s 7#hdba7 - ,fe,s #agf ,fe #aac ,fe #dj ,in actual practice however1 the matte resulting from the reverberatory smelting of the charge had the composition-- ,cu #de per cent4 ,s #bg ,fe #bh the #c per cent4 loss of sulphur causing a #ae per cent4 increase in the copper contents of the matte4 ,experience in the working of the plant enables the management to determine this important factor with fair accuracy1 and thus from a knowledge of the composition of the roaster product1 to regulate and control the grade of the matte produced at the reverberatories4 ,in modern reverberatory practice1 therefore1 the control of the furnace products is carried out at the roasting plant1 and the reverberatory furnace has simply to melt the charge and ensure good settling4 ,anaconda ,practice affords a good illustration4 ,the foreman of the reverberatory furnaces simply charges what is sent him from the roasters1 and practically nothing else is put in1#i his duty being to smelt this mixture and to obtain from it a clean slag and fluid matte4 ,he is not responsible for the grade of the matte1 and if this is not satisfactory1 some change is made in the working at the roasters4 ,the reverberatory foreman does not learn the composition of the materials passing into his furnace until he is furnished with the daily assay reports on the following day4 ,reverberatory smelting is essentially a ,british process1 developed in ,wales1 as already explained1 owing to a plentiful supply of good furnace coal yielding a long flame1 and also of good refractory material4 ,many ,swansea workmen were1 in the early days of ,american development1 and are still1 employed in charge of such copper furnaces1 and it is largely due to ,british technical skill and to ,american genius for organisation and development that reverberatory smelting in the large furnaces at modern works has become so very successful4 ,the ,principles of ,modern ,practice4--,success in modern reverberatory work has been due to the recognition of the fact1 that with the maintenance of constant high temperature on large masses of material1 thorough fusion and separation of the products can be very efficiently conducted4 ,the ,requirements for ,successful ,reverberatory ,work4--,since the action in the furnace is performed mainly by the effects of heat1 it is necessary that-- ,a4 ,the melting should be as rapid as possible4 ,b4 ,the losses of heat during melting should be reduced to a minimum4 ,the temperature required for the formation of slag and for obtaining a thorough fluidity of the materials is from #a1djj to #a1fjj ,c41 and the methods of achieving the proper conditions can best be stated as the avoiding of all circumstances likely to cool the furnace or to interfere with the melting down of the charge4 ,a4 ,to ensure rapidity of melting1 it is essential that a very large quantity of coal shall be burned as rapidly as possible4 ,this requires-- i4 ,a large grate area4 ii4 ,a good draft4 iii4 ,the firing and grating to be conducted so as to interfere as little as possible with the regularity and degree of heating4 ,in localities where a supply of suitable coal is not available1 other methods of heating1 such as the use of oil or gaseous fuel1 are necessary4 ,b4 ,to prevent heat losses as much as possible1 it is necessary-- i4 ,to avoid leakages of cold air into the furnace4 ii4 ,to prevent radiation of heat through walls and roof4 iii4 ,to prevent the hearth from being cooled by the withdrawal of heated charges and the substitution of fresh and cold ones4 iv4 ,to utilise the heat of the already melted charge for the heating up of the fresh ore4 v4 ,to avoid as much as possible1 waste of heat by the escaping gases4 ,a4 ,,for ,,rapidity ,,of ,,melting4 ,a4 i4--,enlarged ,grate ,area4--,in the older methods of working1 there was a general tendency to employ a furnace of standard size1 and improvements in the economy of the process were in the direction of reducing the fuel bill as much as possible for the given size of furnace4 ,this was effected by keeping the grate area fairly small4 ,in modern practice1 economical working still involves having the ratio of size of hearth to size of fire-box as large as possible1 but instead of reducing the dimensions of the fire-grate to suit the hearth1 a large grate is built to commence with1 and the hearth is constructed of such a size as will utilise all the heat available4 ,from this principle of burning a large quantity of fuel and melting with it as much charge as possible1 the efficient and economical working of large furnaces has been developed4 ,a grate area of about #bh square feet is now regarded as the minimum for economical work at modern smelters1 and fire-boxes up to #abh square feet in area are usual in practice4 ,in small fire-boxes1 only small quantities of fuel can be burned at once1 and in consequence1 fresh firing is continually required1 which interferes greatly with the work of the furnace and decreases the rapidity of heating4 ,each addition of cold fuel has a cooling effect on the fire and furnace gases1 the temperature in the hearth being found to drop for a period of five or ten minutes by as much as #ajj ,c41 the flame becoming smoky1 red1 and cold4 ,a similar time is required for the original temperature to be attained once more4 ,cold air is also admitted every time the fire-box doors are opened for charging4 ,the advantages of large grate area therefore include3-- 7a7 ,much less cooling of the furnace by frequent additions of fuel4 7b7 ,higher temperatures1 owing to the increased calorific intensity of large quantities of fuel burned at once4 7c7 ,less blanketing of the fire by fuel additions4 7d7 ,less chance of the whole of the grate area being clinkered up at once1 and in consequence1 less likelihood of interference with the rapid combustion of the fuel4 ,the most rapid and economical smelting at the present day requires that at least #jg lb4 of coal be burned per minute per square foot of hearth area4 ,a4 ii4--,draft4--,the charge in a reverberatory furnace hearth is melted chiefly by the heat from the hot gases passing over it1 and in giving up their heat to the charge1 the gases become cooled down4 ,the heating of the charge is made continuous by the continual addition of fresh fuel in the fire-box1 and by the drawing of the flames over the hearth by means of flues situated at the other end of the furnace and leading to the stack4 ,the flues and stack must be large enough to cause sufficient draft through the furnace for the heated gases to be drawn over the charge with sufficient rapidity1 and much unsuccessful work has been due to the fact that these requirements have not been fulfilled4 ,there should be a suction equivalent to at least #a inch to #ae inches water pressure up the stack1 this being readily measured by water-manometers--a feature of modern working4 ,reverberatories may be worked either by forced or natural draft1 the latter being usually preferred1 though it necessitates a large stack and spacious flues4 ,forced draft by fan or blower under the fire-grate has been in use at several smelters1 the ashpit then being closed4 ,it was at one time adopted at ,anaconda1 but was given up later4 ,the use of forced draft has the advantage that leakages of cold air into the furnace are to a large extent prevented1 hot gases tending to be forced out rather than cold air drawn in1 but the objections to its use include the facts that-- 7a7 ,special power and machinery are required4 7b7 ,the intense action near the fire-bars produces1 from the ash of the coal1 a massive clinker in a semi-fused condition1 difficult to deal with4 7c7 ,it is stated by smelters to have a cooling action near the fire-bridge4 ,a4 iii4--,firing and ,grating4--,this question is closely connected with the dimensions of the grate1 since the use of a small fire-box necessitates methods of firing and grating which are not conducive to the most rapid and efficient combustion of the fuel4 ,in addition to the cooling action of frequent fresh fuel charges in the small fireplace1 attendant disadvantages include the closing up of the spaces in the grate by which air enters for burning the fuel1 and the consequent necessity for frequent grating with small beds of fuel1 which entails numerous objections4 ,the addition of fresh coal to the fire causes the production of large quantities of volatile hydrocarbons which require an increased air supply for proper combustion1 and this air admission is just prevented by the blanketing action of the fresh fuel added4 ,this is indicated by the red smoky flame1 and means waste and cooling4 ,the difficulty is overcome by the arranging of a series of air-holes at the fire-box end of the furnace1 near the fire-bridge1 and by the opening of these directly after firing1 the volatiles are immediately burnt up4 ,this is an important feature in successful working1 and with a large fire-grate and this air-admission1 the effect of adding even #a tons of fuel on to the fire at once causes little difference in the furnace temperature4 ,the flame is observed through a window let into the off-take flue1 which allows of the changes in appearance being noted by the fireman on the fire-box platform4 ,the fire is kept moderately shallow1 to allow of rapid burning of the fuel1 though deep enough to keep up the enormous body of heat necessary in the furnace4 ,b4 ,,the ,,prevention ,,of ,,heat ,,losses4 ,b4 i4--,avoiding ,leakage of ,cold ,air4--,the admission of cold air was the cause of much waste in the older processes of working4 ,each time the doors were opened1 either at the fire-box1 or during charging on to the hearth1 large quantities of cold air were admitted2 air entered through the working door whilst slag was skimmed off1 whilst matte was being tapped1 and whilst the furnace hearth was being clayed2 all of which operations occupied considerable time4 ,the doors were opened during the levelling down of the fresh charges1 and at later periods when the charge was stirred and the half-fused masses sticking to the bottom were worked up4 ,in modern practice1 an essential feature of working is to keep all the doors closed as much as possible1 and1 as will be indicated shortly1 every means is taken to eliminate the heat losses from the causes just referred to4 ,air leakage is also occasioned by bad grating1 which causes the formation of channels in a few parts of the bed of fuel1 admitting excess of air at these places1 instead of causing it to come regularly through the bed in all parts4 ,channelling is now checked by the drop of suction-pressure in the flues1 as registered by the manometer4 ,b4 ii4--,prevention of ,radiation through ,walls and ,roof4--,such heat losses are now minimised by thickening these parts1 and blanketing the outside of the roof with sand1 keeping the construction together by very heavy bracing4 ,b4 iii4--,prevention of ,cooling of the ,hearth on ,withdrawal and on ,charging4--,by far the most important cause of heat losses in working was occasioned by the withdrawal of the whole of the melted products1 the charging of fresh cold ores1 and the efficiency of the furnace was very greatly reduced in consequence4 ,in the older methods1 fully three-quarters of the time and fuel1 and almost all the labour1 were spent in manipulating the charges and bringing them up to the point of fusion1 the actual smelting operation being responsible for but a small proportion4 ,the withdrawal of the hot slag and matte abstracts much of the heat of the furnace1 and the cold charge which is fed in1 not only cools the furnace hearth on which it rests1 but being a poor conductor1 prevents the heat from again penetrating through it to the hearth and to the undermost portion of the charge4 ,it has been estimated through the use of pyrometers1 that the temperature in the furnace after such withdrawal and recharging may drop to less than #gjj ,c4--a dull red heat--and there is no way under such circumstances of heating up the hearth again1 except by conduction through the charge4 ,some hours' hard firing were thus required to bring the furnace to the desired temperature again1 after which it was necessary to re-open the working doors1 in order to stir the materials so as to prevent the half-fused masses1 still lying on the hearth1 from sticking to it4 ,this also occasioned delay in the operations1 and caused much waste of fuel1 heat1 and labour4 ,b4 iv4--,utilising the ,heat of ,melted ,charges for the ,heating of ,fresh ,additions4--,all the above difficulties1 and many others1 have been overcome by maintaining a deep pool of hot molten matte in the furnace1 and by feeding hot charges upon this matte layer4 ,these are two of the most vital and successful changes introduced into modern reverberatory practice1 and will be reviewed in detail subsequently4 ,b4 v4--,utilising the ,heat of the ,escaping ,gases as much as possible4--,improvements in this direction have been brought about-- 7a7 ,by constructing the furnace of as great a length as will allow of maintaining the charge in a sufficiently fluid state to permit of its being tapped from the furthermost end of the furnace4 7b7 ,by using the still hot escaping gases under boilers4 ,modern ,reverberatory ,practice4--,the requirements for the successful operation of the reverberatory furnace1 and the methods for ensuring its efficient working which have just been reviewed1 involve the application of the following principles1 which are the essential factors in modern reverberatory smelting practice3-- #a4 ,the grade of the furnace products is controlled at the roasters4 #b4 ,the melting must be as rapid as possible4 #c4 ,the employment of very large furnaces4 #d4 ,the use of a heated matte-pool in the furnace4 #e4 ,the charging of hot calcines4 #f4 ,the regulation of the furnace working by draft pressures4 #g4 ,the continuous working of the furnace4 #h4 ,modified constructional details4 #a4 ,control of ,furnace ,products at the ,roasters4--,this feature has already been indicated in dealing with roasting practice4 ,the importance of this system in the economy and efficiency of the furnace working is very marked4 7a7 ,the roasting plant affords the most ready means of control over the desired sulphur elimination1 this being its sole function4 ,the modern roaster is so designed as to allow of almost perfect regulation in this respect1 since amount of feed and rate of passage of the sulphides through the furnace are under perfect control4 7b7 ,the work of the reverberatory is thus confined to one object only1 that of rapid melting down1 to which the foreman can give his sole attention free from the necessity of manipulating the grade of the matte at the same time4 ,in modern work it is usual to pass the whole of the charge 7concentrates as well as flux7 intended for the reverberatories1 through the roasting plant4 ,the advantages of such procedure are-- 7i47 ,the flux is preheated at little extra expense1 there being usually plenty of heat to spare for this1 and the roaster capacity is not unduly decreased4 7ii47 ,intimate mixing of the charge is assured1 and this greatly facilitates the fusion and reaction4 7iii47 ,more rapid and thorough roasting is effected1 since the presence of the inert flux prevents clotting or undue sintering of the sulphides in the roaster4 7iv47 ,the charge is found to be in a much better condition1 both physically and chemically1 for successful reverberatory smelting4 ,lime in the roaster charge appears to assist the thoroughness of the roast1 whilst an incipient slag formation is commenced owing to the juxtaposition of basic oxides and silica1 in the hotter parts of the roaster furnace4 #b4 ,rapidity of melting is an indispensable feature of modern work4 ,the conditions necessary for rapid melting have been reviewed above4 #c4 ,use of ,large ,furnaces4--,reverberatory furnaces appear to have replaced the blast furnace in ,great ,britain somewhere about #agjj1 and by #ahed they were in general use in this country4 ,at this period the usual dimensions were1 for the hearth #ac feet by #i feet1 with a fire-box #d feet by #d feet1 the furnace having a capacity of #ab tons per twenty-four hours4 ,in ,great ,britain the size increased very slowly1 and it was in the ,united ,states of ,america that the important increase in dimensions and in enormous outputs were developed4 ,the work was commenced systematically in about #ahgh by ,richard ,pearse 7a ,swansea-trained metallurgist7 at the ,argo ,smelter in ,colorado4 ,table ,v4 indicates the gradual improvements in practice resulting from these developments 7see also ,fig4 #bc1 p4 #ij74 ,,table ,v4--,,development ,,in ,,size ,,of ,,the ,,reverberatory ,,furnace4 ,firebox ,hearth ,tons ,ore per ,year4 ,dimensions4 ,dimensions4 ,stack ,capacity4 ,ton ,coal4 #ahgh1d' #f #e' #i' #h #ae' #b' #iab tons4 #bd tons4 #ahhb1d' #f #e' #aj' #d #ag' #ajb' #iag #bdc #ahhg1d' #f #e' #fab' #h #ba' #bc' #jbd #bfg #ahia1d' #f #f' #ad' #b #bd' #dc' #jbh #bh #ahic1e' #f' #faf' #cj' #c' #fce 7#dc7bg 7#cc7 #ahid1e' #f' #faf' #ce' #d' #j 7#ej7 7#cg7 #aijc1e' #f #aj' #bj' #ej' #e' #e 7#gj7 7#ca7 #aiaj1h' #af' #ai' #aaf' 44 7#bge7 7#dff7 ,the charges of calcines were fed whilst still red hot4 ,this practice has been continued in modern smelter work1 the developments being in the direction of attempting to melt the largest possible quantity of charge in one furnace as rapidly as possible4 ,this has been found to depend upon the rapidity with which the fuel is burned1 and the enlarging of the fire-box had a specially important influence in effecting this rapidity of combustion4 ,then1 with the size of grate fixed and the most efficient burning of the fuel arranged for1 the capacity of the furnace depends simply on increasing the area of the hearth to as great an extent as the heat generated is capable of maintaining at the desired temperature4 ,the breadth of the furnace is however1 limited by-- 7a7 ,the span of arch which can be supported in the construction4 7b7 ,the length of the tools which can be conveniently managed4 ,the maximum width so far found satisfactory is about #ai feet1 so that this dimension being fixed1 the furnace capacity is enlarged by increasing the length1 and this is limited only by the distance from the fire-box to which the flame can maintain the temperature necessary for keeping the charge in a state of perfect fluidity4 ,for many years the length was regarded as limited to #ej feet1 smelting about #bg to #cj tons of charge per ton of coal1 but ,e4 ,p4 ,mathewson1 at ,anaconda1 finding the escaping gases still very hot1 gradually increased the length of the hearth1 first to #fj feet1 then to #hj feet1 and finally up to #aaf feet1 when the furnace smelted #dhc to #ej tons of charge per ton of coal4 ,the gases then left the furnace at a temperature of about #iej ,c41 and contained sufficient heat to fire two ,stirling boilers1 each of #cge ,h4,p4 ,every furnace thus provided about #fjj ,h4,p4 from this waste heat1 and the gases finally escaped at a temperature of #cbj ,c4 ,illustration3 ,fig4 #bc4--;,development of the ,reverberatory ,furnace 7,gowland74 ,the capacity of these large furnaces is about #bgj to #cjj tons of charge per day1 and in addition to the economy and efficiency resulting from the treatment of such large quantities of material at once1 there are the further great advantages in that-- 7a7 ,settling of matte and slag is much more perfect when such large quantities of fluid material are stored4 7b7 ,tapping of matte and slag is easier and more efficiently conducted4 ,about #aaj feet appears to be the practicable maximum for furnace length1 and reverberatories of this size are being constructed wherever circumstances permit1 several new smelters having erected such furnaces--there are eight at ,anaconda1 ,mont42 two at ,garfield1 ,utah2 five at ,tooele1 ,utah2 four at ,cananea1 etc4 ,the length of the hearth is naturally dependent upon the character of the fuel1 particularly the length of flame given out on burning4 ,bituminous fat coals are the most suitable for this purpose1 and in localities where such fuel is not available1 the use of liquid fuel has now been successfully adopted4 #d4 ,maintaining a ,heated ,matte ,pool in the ,furnace4--,this is probably the most important and beneficial advance made in reverberatory practice4 ,in certain stages of the old ,welsh process1 a store of matte was retained in the furnace after skimming off the slag1 but the object was to collect a sufficiently large quantity of matte in the furnace for convenient tapping out4 ,the modern practice has several objects and possesses enormous advantages-- 7i47 ,it assists efficient settling4 7ii47 ,it conserves the heat inside the furnace4 7iii47 ,it presents a highly heated surface for the fresh charge to fall upon1 and thus greatly increases the rapidity of melting1 by ensuring that the charge is heated both from above and from below4 7iv47 ,it prevents the sticking of half-fused charges to the furnace bottom1 the removal of which masses would necessitate much labour1 and occasion cooling of the furnace by the opening of working doors4 7v47 ,it preserves the furnace bottom4 ,liquid matte has practically no action on the siliceous material of the hearth1 and so presents an inert mass between the bottom and the charge4 ,this charge consists of calcines 7mainly oxides of iron71 which would1 during the process of melting down1 slag with and corrode the furnace hearth were it not protected by the matte layer4 7vi47 ,it allows of continuous charging and withdrawal of materials1 and of continued high temperature in the furnace1 thus protecting the furnace lining from much wear and tear4 ,nothing damages furnace linings more than exposure to changes of temperature1 on account of the continual expansion and contraction of the brickwork and the low thermal conductivity of the silica4 ,furnace linings wear out much more from such action than from long exposure to continued high temperature4 7vii47 ,there is effected an enormous saving of time1 fuel1 and labour by maintaining a constant high temperature1 instead of having to heat the furnace up again after each tapping and charging1 as was the case with the older methods of working4 7viii47 ,the levelling of the charges in the furnace is greatly facilitated4 ,the charges would otherwise pile up under the charging hoppers1 and form heaps which are not only difficult to melt down1 but which tend to stick to the furnace bottom1 requiring time and arduous labour for their removal4 ,in modern practice1 charges in quantities of #aj to #ae tons at a time maybe dropped in1 these merely spread themselves out on the bath of molten material and float down in a thin stream towards the skimming door at the end1 and they generally melt and disappear when half-way down the furnace4 ,by this means1 the working doors at the side need practically never be opened for manipulating the fresh charges4 #e4 ,the ,charging of ,hot ,calcines4--,this improvement was also introduced by ,pearse1 and possesses very many advantages2 he was able to increase the furnace output by #bc per cent4 with the aid of this device4 ,instead of allowing the materials from the roasters to cool down1 they are taken straight from the roaster bins to the hoppers which feed the reverberatory furnace1 where they retain much of their heat until charged into the furnace1 being then still red hot as a rule4 ,much time and fuel is thus saved owing to the charge requiring less heating up1 and the cooling action of charging is diminished4 ,a charge of #ae tons is completely melted within an hour4 #f4 ,regulation of ,furnace by ,draft ,pressure4--,it has already been pointed out that rapid combustion of fuel1 and consequently rapid melting1 is greatly assisted by good draft through the furnace4 ,in modern practice1 where the factors1 such as charge composition1 nature of fuel1 and furnace proportions1 have been satisfactorily arranged for independently1 the actual working of the furnace is regulated by the draft pressures4 ,these are registered automatically by water-manometers arranged at various points4 ,one usually communicates with the furnace1 above the fire-bridge2 another is connected to the down-take flues4 ,the indications of these instruments enable a record to be kept of the various operations1 and of the charging of the furnace1 as well as of the condition of the fire4 ,the usual draft pressure worked with corresponds to about #jh inch of water1 registered above the fire-bridge4 ,on opening the hopper for charging1 the pressure drops almost to zero2 the opening of any doors causes a reduction in pressure2 the charging of coal is also rendered noticeable by a drop in the record4 ,reduction of pressure also indicates 8airing0 of the furnace by an excess of air entering through channels in the bed of coal2 draft-pressure thus acting as a check on the firing and also on the grating1 since the formation of excessive clinker in the fire-box is indicated by an increase in the pressure4 ,corresponding to such record over an #h-;hour shift1 as shown on fig4 #bd1 ,offerhaus noted the following furnace manipulations1 illustrating how accurately the operations are checked by this method3-- a4m4 #g4jj-g4ad ,skimming 7coal charged during this period74 #g4af-g4af ,side door opened4 #g4bh-g4ca ,coal charged4 #g4eb-g4eg ,charged4 #h4je-h4ae ,tapped4 #h4ae ,coal charged4 #h4dj ,coal charged4 #h4ed-h4ei ,grating4 #i4je ,side door opened4 ,charged4 #i4bg ,coal charged4 #i4di ,coal charged4 #aj4jg ,charged4 #aj4be ,coal charged4 #aj4da ,coal charged4 #aj4de-aj4eh ,skimming4 #aa4jd ,coal charged4 #aa4af ,charged4 #aa4af-aa4ce ,some grating4 #aa4cf ,coal charged4 #ab4jc p4m4 ,coal charged4 #ab4jd ,charged4 #ab4cg-ab4dh ,tapped1 #a ladles 7about #aa tons74 #ab4de ,coal charged4 #a4jj ,charged4 #a4aa-a4de ,grating4 #a4bf ,coal charged4 #a4dd ,charged4 #a4ea ,coal charged4 #b4ah ,coal charged4 ,total charges during shift1 #af coal1 #g calcines4 ,the draft record is placed close to the charging platform1 in order to be in a convenient position for the guidance of the workmen4 ,the draft in the main flues is #ag to #ah inches water pressure2 this is similarly recorded in the foreman's office4 #g4 ,continuous ,working of the ,furnace4--,the continuous working of the furnace is a most important factor in modern practice1 and is naturally inseparably bound up with the principle of maintaining the heated matte-pool in the furnace1 which allows of the continuous charging of hot 8calcines10 and the continuous or regular withdrawal of slag and of matte when required4 ,illustration3 ,fig4 #bd4--;,draft ,pressure ,record of ,anaconda ,reverberatory ,furnace 7,offerhaus74 ,the matte 7which can be efficiently settled1 owing to the prevailing high temperature and the large mass of heated material in the furnace7 is stored there until required at the converters1 when the desired quantities are tapped out4 ,the slag which is produced by the smelting action gradually accumulates1 and at regular intervals most of it is run out 7rather than skimmed74 ,this usually takes place every four hours4 ,the slag accumulates until it reaches a level some #c or #d inches above the skimming plate at the end of the furnace1 and the quantity which is run out at each 8skimming0 amounts to some #fj or #hj tons1 the contents of the furnace being lowered to such an extent that a fresh accumulation of material may proceed during the next four hours4 ,no pulling of the slag is required as in the older methods of working1 since the material is so very hot and fluid that it simply pours out of the furnace1 and twenty minutes usually suffices for the whole of the #fj or #hj tons to run off1 the rabble being used chiefly to regulate and control the stream1 and to keep back siliceous crusts or floaters4 ,the slag is run out until the matte is seen underneath1 on flapping back a thin layer1 or until the level of the skimming plate is reached1 and its removal is such a short and simple operation that there is very little interference with the regular and continuous running of the furnace4 ,similarly1 the tapping of as much as #ej to #ajj tons of matte from the store of #bej tons of hot fluid material has little influence on the continuous working4 ,charging of coal and calcines is performed at regular intervals1 and the charges of #ae tons of 8calcines0 fed in at a time1 readily melt down and settle4 ,practically the only interference with continuous running is the necessity for claying and repairing1 and the use of the matte pool on the hearth has lessened the frequency for this to a large extent1 the hearth bottom itself being protected from corrosion1 owing to the sulphides exerting no action upon it1 whilst the oxides in the charge which would be capable of attacking the siliceous bottom are slagged off before they get an opportunity of reaching it4 ,the hearth bottom1 if properly put in1 is practically permanent4 ,the portion of the furnace most subject to corrosion is at the slag line1 where deep channels are gradually cut out4 ,every four to six weeks the furnace is tapped dry1 repaired1 and fettled1 as much as #bj tons of fettling sand being often required for this purpose4 ,the sand is thrown in and patted into place by long rabbles1 the operations occupying about eighteen hours4 ,every nine months or so the furnace is repaired more fully1 #bj or #cj feet of brickwork near the fire-bridge being taken down1 and the great cavities in the side walls repaired by masons1 using silica bricks4 ,the employment of higher temperatures in modern work allows of more siliceous slags being produced1 which lessens the tendency to the eating away of the walls4 ,the feeding of siliceous copper ores through a series of small hoppers situated in the roof1 near to the walls1 has lately been introduced with a view to protecting the furnace sides from the corrosive action of the slag1 and to exposing a suitable siliceous flux to this material4 ,this appears to have fulfilled its purpose to some extent1 but various difficulties have been encountered in practice1 especially the tendency for the cold added material to form floaters1 which require limestone additions in order that they may be fluxed off2 and the cooling effects and leakages through the openings have also given trouble4 #h4 ,modified ,constructional ,details4--,in addition to the increased size of fire-box1 hearth1 and flues1 and to the necessity for very heavy staying in order to keep the enormous arch in permanent shape1 which are characteristic of modern practice1 the construction of modern furnaces involves the building of a suitable hearth to carry the heavy burden of hot and fluid matte which is stored in the furnace4 ,it was formerly considered correct practice1 in the smaller types of furnace1 to construct the hearth over a vault1 in order to keep the underside cool and thus prevent the corrosion and eating away of the siliceous bottom by the oxidised charges1 during the process of melting down4 ,in modern practice it is absolutely essential to work with a perfectly solid structure4 ,illustration3 ,fig4 #be4--,skimming ,reverberatory ,furnace1 ,anaconda4 ,illustration3 ,fig4 #bf4--,transverse ,section of ,modern ,reverberatory ,furnace1 ,anaconda1 indicating ,foundations1 ,hearth1 and ,bracing4 7a7 ,because the hearth must be kept as hot as possible1 so as to ensure rapid melting of the charge and maintain the products in a perfectly fluid condition4 ,any circumstance tending to cool the hearth is rigorously avoided1 this being the contrary of the older practice4 ,the protective influence of the heated matte-pool in modern work preserves the bed from the corroding effects of fresh oxidised charges1 and in consequence1 the maximum degree of heat can with safety be maintained on the furnace hearth4 7b7 ,the enormous weight of charge and the heavy arch and walls demand the strongest possible foundations and support4 ,illustration3 ,fig4 #bg4--,reverberatory ,furnace under ,construction4 ,in building modern reverberatories1 the foundation for the hearth is constructed of solid masonry or brickwork1 or as at ,anaconda1 of a solid bed of slag1 some #bd inches in depth1 run in from an adjacent furnace4 ,the ,i-beams used for carrying the bracing are erected in a surrounding trench1 and a further quantity of slag 7#d feet thick by #b feet deep7 is run in1 thus yielding a perfectly rigid and impervious foundation 7,fig4 #bf74 ,on the top of this slag-foundation is built a layer1 #ab inches thick1 of silica bricks1 and upon this1 the actual working bottom of the furnace is constructed4 ,this bottom is now put in also in a manner different to the older practice1 and excellent results have accrued from the change4 ,the old method of constructing sand bottoms consisted of putting in the beds of sand1 layer by layer1 and thoroughly fritting each one before the addition of the next3 in modern practice1 it is found that proper consolidation is not attained with beds of the enormous area now employed1 when the bottom is constructed in such layers4 ,the present method of working the reverberatory furnace is not to drop the charge on to the sand hearth at all1 but into the deep pool of matte1 and the sand-hearth is regarded more as a convenient foundation for the support of this liquid working-bed1 on account of its constituting a cheap non-conducting and fire-proof material which is unaffected by the materials resting upon it4 ,it was found1 however1 on commencing this matte-pool practice1 that the older method of putting in the bottom in successive sand layers was not suitable for this work2 after a little wear1 the beds became raised in layers1 this being especially the case if any holes happened to be eaten through in places4 ,moreover1 the large weight of matte tended to find its way down between the layers and raise them up bodily1 or else it worked down at the edges of the hearth and side walls1 and either broke out underneath the former or through the latter4 ,when it was ascertained that liquid matte itself had no corrosive action on the siliceous hearth if the latter be kept constantly covered1 and that the causes of breakouts were principally due to mechanical weaknesses1 it required only improvements in design and construction in order to avoid them4 ,this is now attained by constructing the bed in a compact and perfectly massive form1 and is best accomplished by putting in the whole layer of #bf inches of sand at once1 and firing as hard as it is possible for the brickwork to stand4 ,the method has met with exceptional success in practice1 rigid and impervious hearths are obtained2 it being found that less than #a inch has worn off the bed after two years' working4 ,illustration3 ,fig4 #bh4--,sectional ,plan and ,elevation of ,reverberatory ,furnace at ,anaconda4 ,large ,reverberatory ,furnaces3 ,details of ,construction4--,the large furnaces at ,anaconda were the first of the modern type to be constructed1 they have met with enormous success in practice and constitute the standard form4 ,similar furnaces are now in operation or under construction at many of the large modern camps1 and are of similar design and construction4 ,the hearth is #ajb to #aaf feet long by #ai feet wide4 ,grate1 #af feet by #h feet #abh square feet grate area4 ,ratio of hearth to grate area is #af 3 #a4 ,distance from hearth to level of fire-bridge1 #bf inches2 hearth to crown of arch1 #f feet #e inches4 ,walls are #bf inches thick4 ,roof is #ae inches thick 7except for #d to #f feet over the fire-bridge1 where it is #bj inches74 ,the bracing of the furnace is necessarily particularly strong 7see ,fig4 #bi74 ,lined inside with silica brick1 said to be the finest in the world4 ,the bed is of the finest ,dillon sand 7#ige per cent4 silica71 ground to pass -inch mesh2 the bed has a slope of #h inches towards the tap-holes1 of which there are two4 ,during the construction of the large furnace there are left in the roof ten expansion openings of #c inches each1 which by the time the furnace has attained its working temperature1 become closed up 7see ,fig4 #cj74 ,the conker plate which runs through the fire-bridge is #ad to #ae feet long1 and is made thicker near the furnace side1 where it is #c inches thick4 ,the air space through the plate is #b feet #c inches by #i inches1 and serves the purpose of keeping the fire-bridge cool2 air passes through it continuously1 and if the plate shows signs of becoming hot1 a blast of cold high-pressure air is sent through it4 ,still further heating of the plate and signs of red heat are an indication that the #b feet of silica of the fire-bridge wall are being burnt through4 ,working of the ,reverberatory ,plant at ,anaconda4--,the plant consists of eight large furnaces1 built parallel to one another1 seven being usually at work whilst the eighth is undergoing repair4 ,each furnace treats #cjj tons of hot calcines and flue-dust daily4 ,charging4--,the furnaces are charged every #fe to #gj minutes with #ae-ton charges1 and as soon as one charge is melted1 another is added2 with average running1 #aej charges are worked in the seven furnaces daily4 ,the charge train1 consisting of an engine and three cars1 each of which carries #e tons of charge1 travels from the roasters and enters the reverberatory building by an overhead track running above the charge bins of the furnaces4 ,it discharges through hoppers into the bins which extend across the entire width of the hearth4 ,bins were formerly arranged at intervals all the way down the furnace1 but now only the two bins nearest to the fire-bridge are employed4 ,into the back bin1 #aj tons of charge are placed1 and into the other1 #e tons4 ,each of these bins discharges through two hopper discharge openings1 feeding the furnace through holes in the roof 7,figs4 #bi1 #cj71 which are closed1 when not in use1 by round firebrick tiles #bj inches in diameter and #b inches thick2 these are moved in and out of position by means of levers operated from the fire-box platform4 ,the temperature maintained in the furnace is high1 approximating to #a1ejj ,c41 and just previous to dropping in a fresh charge1 a workman1 by means of a rabble1 feels about the hearth below the charging hopper in order to ensure that all of the previous charge has been melted1 and that none of it is sticking to the furnace hearth4 ,by employing only the comparatively small quantities of #ae tons1 this sticking is avoided1 since such charges are not heavy enough to sink unmelted through the #h inches of slag and #h inches of matte in the furnace4 ,the former practice of feeding charges amounting to #de tons through hoppers situated all the way along the furnace had given serious trouble in that respect1 and had consequently to be discarded4 ,when the examination of the hearth is completed1 the time occupied being very short1 the side door is closed1 and sealed with sand2 the covers to the holes in the roof are now withdrawn1 the gates closing the hoppers pulled back1 and first the #e-ton1 then the #aj-ton charge is dropped into the furnace4 ,the whole operation1 including the preliminary opening of the door to test the furnace bottom1 occupies five minutes4 ,very little hand labour is required round these enormous furnaces1 except for the grating of the fires1 for the charging of coal and calcines every hour by the operation of levers from the fire-box platform1 for the skimming of slag at intervals of four hours1 and for the tapping of matte when required4 ,the whole of this work is conducted by the skimmer and two helpers to each furnace1 one of the men also looking after the boilers4 ,as soon as the charge has been dropped on to the pool of molten material1 the mass appears to spread out over the surface and float towards the skimming door1 in a thin slow-moving stream which disappears when about half-way down1 being usually melted within one hour4 ,the former #dj-ton charges required as much as eight hours for melting4 ,owing to the great heating effect of the large bath of hot material below1 and of the intense flame above1 there is but little cooling action on adding the fresh charge2 whilst with this length of furnace1 practically all the dust is settled1 and very little is carried into the flues4 ,coaling4--,the quantity of coal employed amounts to #bj to #be per cent4 of the charge1 or about #ej to #fj tons per day per furnace1 #a ton of coal smelting rather less than #e tons of calcines4 ,illustration3 ,fig4 #bi4--;,fire-box ,end of ,reverberatory ,furnace1 showing massive ,bracing1 ,charge ,bins1 and ,charging ,levers--,anaconda4 ,illustration3 ,fig4 #cj4--;,interior of ,reverberatory ,furnace 7looking towards ,skimming ,door71 showing ,expansion ,spaces in ,roof1 and ,charging ,holes--,anaconda4 ,coal is charged every #dj minutes in quantities of #a tons at a time1 from bins which extend across the entire width of the fireplace1 feeding through four hoppers into openings #a foot square in the roof of the fire-box1 and the withdrawing of the gates is operated by means of levers at the platform4 ,over the fire-bridge are two rows of air-holes used for regulating the length and character of the flame in the furnace2 the flame1 however1 plays a subordinate part in the smelting reactions4 ,the coal employed is from ,diamondsville1 ,wyoming1 and gives a flame #abe feet in length1 the appearance of which is gauged through the window fixed in the off-take flue1 this being visible from the fire-box platform4 ,the coal is run-of-mine quality1 and considerable slack is used4 ,it possesses a high calorific power and a large proportion of volatile constituents1 but clinkers rather badly1 and a clinker grate is worked with4 ,grating4--,the fire rests upon #c-;inch round bars placed at #d to #f-;inch centres1 and is maintained at a depth of about #bg inches4 ,grating requires to be conducted at fairly frequent intervals1 usually twice per shift1 in order to keep the fire free and to prevent channelling1 which is indicated on the draft gauge by a drop from #jge inch to #jej inch1 due to airing4 ,it serves further to prevent clinkering1 which1 when taking place in the fire1 causes a rise of from #jge up to #aj inch on the gauge4 ,the operation of grating usually occupies about half-an-hour2 the work is arduous1 and the heat to which the workman is exposed is itself very trying4 ,coke ,recovery4--,a constant stream of half-burnt fuel and ashes falls through the bars1 and during the clinkering operations large quantities are dropped4 ,the material all falls down a bank inclined at #de1 into a channel where it is met by a stream of water which washes it along launders and through a grizzle1 to a settling tank4 ,the settled products are subsequently jigged1 the recovered coke being washed over the tail-board to a trommel1 and by this means #aj per cent4 of the fuel charged into the furnace is recovered in a useful form4 ,this coke is used up as a constituent of the briquettes4 ,,table ,,vi4--,,daily ,,report--,,reverberatory ,,furnaces4 ,,august #ag,,th1 #aijh 7,,good ,,day74 ,charge4 ,furn- ,total ,blast ace ,smel- ,cal- ,macdougal ,furnace ,main ,resi- ,no4 ,coal ted cines ,flue-,dust,flue-,dust,flue-,dust,extras dues ,tons ,tons ,tons ,tons ,tons ,tons ,tons ,tons ,fine lime rock4 #a #fjf #bhhh #bgib 44 #hi 44 #jg 44 #b #egb #bggg #bfbg 44 #bi #aah #jc 44 #c #fda #bhfg #becb #abj #hi #aah #jh 44 #d #fje #bghg #bfdg 44 #bf #ci #jb #gc #e #egc #bdei #bbag #abj #aab 44 #aj 44 #f #egc #bgca #bfdd 44 #gi 44 #jh 44 #g 44 44 44 44 44 44 44 44 #h #egd #bghg #bffh #aai 44 44 44 44 ,total#daddaibifahabg #cei #dbd #bge #ch #gc ,cost ,delays4 ,ladles of ,coal of ,furn-,copper per ,wait- ,waiting ,matte ace ,material ,ton ing for ,miscel- ,total,boilers in ,no4 ,smelted of for ,calcineslaneous ,delays,working,furnace per ,ton ,metal ,coal at ,end of ,coal ,melted of ,day4 ,tons 4 ,hours ,hours ,hours ,hours ,hours #a #dgg #jie #bd #aj #b #dhe #jid #bd #aj #c #ddg #ajb #bd #aj #d #dfa #jii ,no delays4 #bd #aj #e #dbi #ajf #bd #aj #f #dgg #jie #bd #aj #g 44 44 44 44 #h #dhe #jid #bd #aj ,total 44 44 44 44 44 44 #afh #gj ,draft1 #ag inches4 ,number of furnaces running1 #gjj ,all furnaces working slow4 ,number of charges1 #adj ,furnace ,no4 #e1 one bad charge4 ,ladles matte tapped1 #cd ,cupriferous material smelted per furnace1 #bgef tons4 ,,daily ,,report--,,reverberatory ,,furnaces4 ,,august #ai,,th1 #aijh4 ,charge4 ,furn- ,total ,blast ace ,smel- ,cal- ,macdougal ,furnace ,main ,resi- ,no4 ,coal ted cines ,flue-,dust,flue-,dust,flue-,dust,extras dues ,tons ,tons ,tons ,tons ,tons ,tons ,tons ,tons #a #eed #adcj #adcj 44 44 44 44 44 #b #eed #bdfd #bdja 44 44 44 44 #fc #c #fba #bejg #bcfi 44 44 #ach 44 44 #d #ehi #bfbg #bfbi 44 44 44 44 44 #e #fbb #bdgh #bdgh 44 44 44 44 44 #f #eia #bdai #bdai 44 44 44 44 44 #g 44 44 44 44 44 44 44 44 #h #eea #bebi #bebi 44 44 44 44 44 ,total1 #djhbafdefafbee 44 44 #ach 44 #fc ,,daily ,,report--,,reverberatory ,,furnaces4 ,,august #ai,,th1 #aijh4 ,cost ,delays4 ,ladles of ,coal of ,furn-,copper per ,wait- ,waiting ,matte ace ,material ,ton ing for ,miscel- ,total,boilers in ,no4 ,smelted of for ,calcineslaneous ,delays,working,furnace per ,ton ,metal ,coal at ,end of ,coal ,melted of ,day4 #a #beh #agf 44 44 #hjj #hjj #bb #b #b #dde #ajb 44 44 44 44 #bd #h #c #djd #aac 44 44 44 44 #bd #f #d #ddf #ajb 44 44 44 44 #bd #f #e #cih #aad 44 44 44 44 #bd #h #f #dji #aaa 44 44 44 44 #bd #h #g 44 44 44 44 44 44 44 44 #h #dei #aai 44 44 44 44 #bd #h ,total1 44 44 44 44 #hjj #hjj #aff #df ,draft1 #ag inches4 ,furnace ,no4 #a delayed #h hours tapping and claying4 ,furnace ,no4 #g down for repairs4 ,bad coal on all furnaces4 ,number of furnaces running1 #ffg ,number of charges1 #aah ,ladles matte tapped1 #dg ,cupriferous material smelted per furnace1 #bdfg tons4 ,tapping the ,furnace4--,matte is usually withdrawn from these large stores upon such occasions as it is required for the converters1 though sometimes when the supply has got ahead of the converters' demands1 the matte is tapped and run outside the reverberatory building1 being cast into large matte-beds4 ,the tap-holes are situated between the second and third doors1 and between the fourth and fifth2 and each consists essentially of a copper plate #b inches thick and #be inches square1 which at first stands back #i inches from the outside of the wall4 ,through this plate a #a-;inch hole has been drilled4 ,the tapping bar is maintained inserted up this hole1 being passed through the conical clay plug which closes it4 ,at the back of the plate is #ba inches of lining material through which the tapping-hole passes4 ,when the copper plate shows signs of a red heat1 it is an indication of the lining tending to burn through2 this part of the furnace is then cooled1 the plate taken out1 a #i-;inch layer of sand is rammed into position1 and the plate is thus moved forward a corresponding distance4 ,such a tap-hole plate lasts for about five months4 ,the reverberatories are usually not tapped until they contain about #bej tons of matte4 ,the operation of tapping is performed by withdrawing the rod by means of a wedge and ring1 when the matte flows along the launders leading to the ladles for the converters2 two ladles of about #h tons capacity each are usually filled at once1 each ladleful being sampled at the runner4 ,the tap-hole is then stopped with a cone of clay1 and the tapping-rod driven through it again4 ,typical daily reports of the furnaces are appended in ,tables ,,vi4 and ,,vii41 and a monthly report on ,table ,,viii4 ,,table ,,vii4--,,from ,,daily ,,assay ,,report--,,reverberatory ,,furnaces4 ,,august #ai1 #aijh4 ,per ,cent ,copper in ,slag4 ,furnace ,number4 ,shift #a4 ,shift #b4 ,shift #c4 #a #jcj #jcj #jcj #b #jcj #jce #jbe #c #jcj #jcj #jce #d #jde #jcj #jbe #e #jcj #jdj #jce #f #jcj #jbj #jbj #g 44 44 44 #h #jce #jbe #jcj ,average in slag1 #jce #jcj #jcj ,si,o#b1 #bie per cent4 ,fe,o1 #cgc ,composition of calcines ,s1 #gg ,ca,o1 #bg ,copper1 #hf ,si,o#b1 #cid per cent4 ,composition of slag1 ,fe,o1 #djg ,ca,o1 #dc ,copper in matte1 #chf ,,table ,,viii4--,,monthly ,,report--,,reverberatory ,,furnaces4 ,,total ,,charge--,,all ,,furnaces4 ,charge4 ,si,o#b4 ,fe,o4 ,tons4 ,per cent4 ,tons4,per cent4 ,tons4 ,calcines and lime rock #ej1jed #bgbj #ac1faf #cidj #ai1gba ,m#8,dougal flue-dust1 #igg #cjej #bih #baij #bad ,blast flue-dust1 #a1fci #ceij #ehh #bbjj #cfa ,converter flue-dust1 #acb #aij #b #ffj #i ,main flue-dust1 #a1jcd #cjb #cab #aghj #ahd ,total1 #ec1hcf 44 #ad1haf 44 #bj1dhi ,matte to converter1 #aj1iej 44 44 #cfgj #d1jai ,matte chips to ,b4,f41 #gd #hbj #f #chaj #bh ,slag chips to ,b4,f41 #fji #ciej #bda #cgdj #bbh ,deduct from above total1 #aa1fcc 44 #bdg 44 #d1bge ,leaves for slag1 44 44 #ad1efi 44 #af1bad ,lime4 ,sulphur4 ,copper4 ,per ,tons4 ,per ,tons4 ,per ,lbs4 cent4 cent4 cent4 ,calcines and lime rock1 #bcj #a1aej #hdj #d1bje #hbff #h1bgd1gii ,m#8,dougal flue-dust1 #acj #acadjj #acg #ghhd #aeb1bie ,blast flue-dust1 #dcj #gj #fgj #aaj #efih #ahf1ghb ,converter flue-dust1 44 44 #abaj #affhgdc #aha1dhb ,main flue-dust1 #baj #bb #hhj #ij #gabh #adg1dje ,total1 44 #a1bef 44 #d1eeh #hcje #h1idb1gfc ,matte to converter1 44 44 #bfdj #b1hiachbji #h1cfg1hgb ,matte chips to ,b4,f41 #jbj 44 #bahj #afcbhaa #dh1efj ,slag chips to ,b4,f41 #bcj #ad #bbj #acceeig #dc1ceg ,deduct from above total1 44 #ad 44 #b1ibj 44 #h1dei1ghi ,leaves for slag1 44 #a1bdb 44 44 44 44 ,analysis4 ,slag ,calculation ,calculated4 ,actual4 ,si,o#b in slag1 #ad1efi #ch1ech #cgh #cga ,fe,o #af1bad #ch1ech #dba #dcb ,ca,o #a1bdb #ch1ech #cb #bh #cb1jbe at #hcag #ch1ech #hcaj #hcaj ,fuels for ,reverberatory ,furnace ,work4--,the chief requirements of the fuel for good reverberatory work will now be apparent1 particularly with regard to length of flame4 ,this depends to a large extent upon the proportion of volatile hydrocarbons1 but also on the conditions under which they are given off4 ,for instance1 a coal which rapidly parts with its hydrocarbons and leaves in the grate a dense layer of slow-burning coke would be unsuitable for reverberatory work1 though some caking is necessary in order that the fuel should not burn away too rapidly1 as it should yield a good bed of the required depth4 ,the great success of large reverberatory furnaces worked under suitable conditions1 has had the tendency to tempt smelters in different parts of the world to erect furnaces of similar size independently of the character of the available fuel1 and in several cases results have been unsatisfactory1 at least in the earlier stages4 ,these preliminary failures have1 however1 served the purpose of developing the adaptation of other fuels for this work1 and from the employment of oil for the purpose1 important extensions in practice will undoubtedly develop in the future of reverberatory furnace working4 ,the device of using pulverised coal as a fuel has attracted attention at several smelters where the local coal as mined was proved to be unsuitable for use4 ,in practice1 however1 the method has1 up to the present1 given unsatisfactory results1 for although a longer flame and higher temperature have been obtained in the furnace1 difficulties in working have arisen which appear to bar its use4 ,one of the chief drawbacks has been due to the fine ash from the fuel1 which is deposited in the flues in large quantities and even causes considerable slagging in them1 impeding the working of the furnace and preventing the recovery of heat from the furnace gases4 ,further difficulty1 though not quite so serious1 was caused by the dust being blown upon the charge and tending to settle upon it2 forming a non-conducting blanket which retarded the melting of the material by the flames4 ,the method does not appear at present to offer much promise of extended application to copper smelting4 ,oil ,fuel in ,reverberatory ,practice4--,the successful application of oil as a fuel marks a useful advance in reverberatory practice1 particularly in connection with the working of large furnaces4 ,on several of the smaller plants1 oil fuel has been in use with considerable success for some time1 but within recent years the building of large-sized furnaces without having at hand suitable coal resources has led to attempts to employ oil in its place1 and the preliminary difficulties appear to have been to a large extent successfully overcome4 ,the work at the ,cananea ,smelter with oil fuel1 and the discussion on ,ricketts' first report of his experience1 afford valuable indications of the possibilities of this method4 ,working on charges consisting to a large extent of flue-dust1 several thousand tons of material have been smelted in furnaces yielding #bde tons daily output1 at a cost which compares very favourably with that of ordinary practice4 ,this success is particularly noteworthy in view of certain features in the preliminary system of working which will doubtless be altered at no very distant date1 and of the fact that flue-dust is sometimes a difficult material to melt in a reverberatory furnace1 even when good coal is available as a fuel4 ,illustration3 ,fig4 #ca4--,shelby ,oil-burner for ,reverberatory ,furnace ,use4 ,the chief difficulties in working appear to have been largely in connection with the regulation of the flame and the management of the oil-burners4 ,in endeavouring to obtain the requisite high temperature over the entire length of the furnace-hearth1 an intense local action was caused near the place where the oil in the form of a spray entered the furnace1 resulting in the burning out of the roof-arch on several occasions4 ,these difficulties will doubtless be overcome with further experience in the design and management of the burners constructed for this class of work4 ,at ,cananea1 four oil burners of the ,shelby type are employed on each furnace1 and this form is stated to project the flame further into the furnace1 and to prevent its impinging on the roof1 more successfully than the other types tried4 ,the waste heat fires three ,stirling boilers of #ffd ,h4,p4 ,less than one barrel 7#db gallons1 or #caj lbs47 of oil is consumed per dry ton of charge1 and of this quantity #jdc barrel is chargeable to steam-raising under the boilers4 ,the manner of working the charges1 and the furnace construction in other respects1 follow very closely the methods of operation already described4 ,costs of ,oil-fired ,reverberatory ,working4--,ricketts has contributed a useful analysis of the costs of reverberatory work using oil as fuel1 under the conditions prevailing at ,cananea1 ,mexico4 ,he noted that the use of too much oil should be avoided4 ,this precaution led to a decrease in the amount of repairs necessary4 #eej barrels of oil were required to get the furnace into fairly good condition1 and #h barrels per furnace per hour to keep it going well4 ,it is hoped ultimately to reduce the oil consumption to #jh barrel gross per ton of charge4 ,analysis of ,oil-fired ,reverberatory ,furnace ,costs--,cananea--,february to ,july1 #aiaa1 inclusive4 ,furnace ,days1 #cabe4 ,,tonnage ,,charged-- ,dry ,tons4 ,per cent4 of ,total4 ,flue-dust1 #ba1jai #cdii ,calcines1 #ce1ecc #eiae ,ores1 #c1jdj #ejf ,limestone1 #dgi #jhj ------------ ------------ #fj1jga #ajjjj ,,distribution ,,of ,,costs-- ,amount4 ,per ,dry ,ton4 ,operating expenses1 #aaa1fhgag #aheic ,slag and matte expense1 #e1aaajg #jjhea ,boiler-house1 #aa1dfhgg #jaiji ,general expense1 #d1baheh #jjgjb ,cost of flux1 #hagdf #jjacf ----------------- ------------- #acc1cjcje #bbaib ,steam credit1 #dh1hfahf #jhacd ----------------- ------------- ,operating cost1 #hd1ddaai #adjeg ,,analysis ,,of ,,costs-- 7#a7 ,operating-- ,amount4 ,per ,dry ,ton4 ,labour1 #ag1hbidb #jbifh ,power1 #eibcf #jjjii ,fuel oil1 #hh1jbhii #adfed ,coal1 #bdcfa #jjjda ,water1 #iafh #jjjae ,transportation1 #chjde #jjjfc ,sundries1 #caefd #jjjec ,flux1 #hagdf #jjacf ----------------- ------------- #ajh1biifa #ahjbi 7#b7 ,repairs-- ,labour1 #aa1jfcic #jahdb ,supplies1 #ab1dbecj #jbjfh ,shop expense1 #a1eadba #jjbeb ---------------- ------------- #be1jjcdd #jdafb ---------------- ------------- ,total1 #acc1cjcje #bbaia ,steam credit1 #dh1hfahf #jhacd ----------------- ------------- ,net total1 #hd1ddaai #adjeg ,gaseous ,fuel4--,the proposal to employ gaseous fuel in copper smelting dates from the introduction of this method of furnace-firing by ,siemens #ej years ago4 ,it is1 however1 not in general use1 although at several smelters gas-firing is employed in furnaces for the refining of the metal4 ,the chief difficulties have been in connection with the control of the flame1 burning-out of the roof having been a not infrequent occurrence when employing gaseous fuel1 and the method has been tried and given up at the ,great ,falls ,smelter in ,montana1 and at several other works4 ,the practical difficulties ought not1 however1 to be insuperable should gas-firing be otherwise found most practicable for the particular conditions at the smelter1 although there appear to be certain physical characteristics of such flames which may be responsible for some of the difficulties met with in employing this type of fuel for the working of very large reverberatory furnaces4 ,the ,condition of the ,charge for ,good ,reverberatory ,work4--,the considerations which decide the advisability or otherwise of installing at a smelter1 any particular types of furnace1 whether reverberatory or blast furnace or both1 cover a very wide field1 and will be more apparent when blast-furnace practice has been reviewed in detail4 ,it is clear that the blast furnace is unsuited for the direct smelting of fine materials as such1 and that the reverberatory form of furnace is best fitted for their treatment when large quantities of this material require to be dealt with4 ,actual practice has shown1 however1 that the reverberatory does not give equally satisfactory results on all classes of fines1 and that there are certain physical and chemical conditions of the charge which appear to be necessary for the most successful and rapid smelting4 ,when such conditions are not adhered to1 less satisfactory working has resulted4 ,recent experience has1 to some extent1 defined more clearly the nature of these requirements1 and has indicated the procedure which is necessary in order to avoid an undue supply of the less suitable material for the reverberatory charge4 ,it is usual to smelt in the reverberatory furnaces1 where such are available1 the greater portion of the dust which accumulates in very large quantities in the flues at the smelter4 ,the reverberatory is the only type of furnace in which such material could be treated directly1 under the present conditions of working4 ,in practice1 however1 it has been found in several instances1 though not universally1 that such dust is considerably more difficult to treat in the furnace1 and entails considerably more expense in smelting than does the ordinary roasted concentrate4 ,it is estimated by ,ricketts that this extra cost is practically equivalent to the expense of roasting an equal weight of concentrate4 ,flue-dust1 as a rule1 consists mainly of material in a minute state of division1 in which condition1 as is well known1 a much higher temperature is required for its fusion than if it were in the form of coarser particles4 ,this is largely due to the poor conductivity for heat which generally characterises such dust1 and to the insulation by the air envelopes surrounding the individual grains1 which thus prevents the heat passing from particle to particle1 and retards their clotting1 even when the prevailing temperature would otherwise be sufficient to cause fusion4 ,the particles of flue-dust moreover1 have been blown from the surface of the charge1 especially in the blast-furnace process1 and are thus rapidly and often almost completely oxidised in passing through the oxidising atmosphere which prevails above the charge and in the flues4 ,such oxides clot only with the greatest difficulty1 and are characterised by comparative infusibility and poor conducting power1 and hence are found to melt with considerable difficulty when treated in the reverberatory furnace4#aj ,roasted fine concentrate1 on the other hand1 constitutes an ideal material for the reverberatory furnace charge1 and the system of passing both the concentrate and the flux through the roasters has been shown to possess numerous advantages4 ,in addition to the thorough mixing and the preheating of the furnace charge1 it was found that its chemical and physical conditions were particularly well suited for the subsequent reverberatory furnace treatment4 ,the particles of concentrate1 being gradually heated and constantly stirred in the presence of the small proportion of flux usually required1 roast well1 and lose the desired quantity of sulphur without an undue amount of preliminary clotting which would otherwise interfere with the operation1 whilst any residual sulphide in the product is uniformly distributed through the roasted charge4 ,in addition1 at the higher temperatures which prevail in the later stages of the roasting process when almost as much sulphur as was desired has been driven off1 the materials are raised to a point approaching incipient fusion and slagging4 ,the heat in the reverberatory furnace is sufficient to complete this effect1 and enable the necessary chemical combinations and physical separations to be readily accomplished4 ,the roasted concentrate should therefore form the main proportion of the reverberatory charge1 working in with it1 in moderate quantities1 such flue-dust as is made at the smelter4 ,of this flue-dust1 it is naturally desirable to produce as small an amount as possible1 not only on account of the difficulties in subsequent treatment1 but also on account of the actual losses in the economy of the furnace processes and the cost of rehandling1 etc4 ,in modern smelting1 naturally1 every effort is made to reduce the quantity of dust to the lowest practicable limit4 ,the greater portion of the dust results from the treatment of unsuitably fine material in the blast furnace1 and by decreasing the quantity of this constituent the flue-dust problem will be largely overcome4 ,the smelting of fine concentrate in the blast furnace has up to the present been considered judicious where circumstances have rendered imperative the addition of sulphides to the charge irrespective of their physical condition 7either to act as a base for the matte1 or on account of their fuel values71 though naturally the proportion of fines has been kept as low as possible4 ,the recent developments in sintering processes1 however1 suggest the possibility of the future successful treatment1 after preliminary agglomeration1 of fine concentrate in the blast furnace1 and if it be found possible to conduct the sintering by utilising the heat of oxidisation of the more free sulphur atom of the pyrites1 and thus leave the bulk of the iron-sulphide fuel values in the sintered product1 as suggested by ,peters1 the difficulties in connection with excessive flue-dust production from the above causes will be largely overcome1 and the reverberatories will thus be relieved of this difficult constituent of their charge4 ,it therefore appears desirable1 when circumstances permit1 either to agglomerate fine concentrates and then treat them in the blast furnace1 or else to roast them and smelt the product in the reverberatories4 ,so far as present experience has gone1 it appears that--other circumstances being equally favourable--the correct scheme of treatment depends almost entirely upon the composition of the concentrate1 there being for each process a particular class of fines for which it is best suited4 ,the sintering process deals most satisfactorily with one class of concentrate1 whilst the roasting process seems more particularly suited for a different type of material4 ,thus the higher the iron and sulphur values1 and the lower the silica content1 the more successful1 cheap1 and efficient is the roasting process--the ,anaconda material for example roasts well1 requires practically no external fuel or heating1 and with the added flux1 works very successfully in the reverberatories4 ,as the silica content increases1 however1 and the iron and sulphur contents diminish1 there is a consequent decrease in the natural fuel values of the material1 and as a result1 the roasting is neither so efficient nor so cheaply operated1 owing to the need of external fuel for giving the required roasting temperatures4 ,on the other hand1 it appears to be just this class of material which is best suited for blast-roasting4 ,it is found in actual working practice that material which does not contain a certain proportion of silica does not work well in the blast-roasting or sintering processes1 the resulting product being found to be more irregular in composition and more difficult to operate in the sintering plant4 ,it would therefore appear that a certain class of fine concentrate higher in silica and lower in iron and sulphur contents1 which is not quite so suitable for ordinary roasting 7owing to the necessity for external heating1 due to lower fuel values7 is eminently suited for blast roasting or sintering processes1 yielding lump products very suitable for subsequent blast-furnace treatment4 ,the reverberatory furnace thus deals most successfully with fine table concentrates high in iron and sulphur1 moderately low in silica2 roasted1 with its required flux1 to the necessary extent1 and then charged whilst still red hot into the furnaces4 ,to relieve the reverberatories of the greater bulk of the blast-furnace flue-dust1 which it treats with more difficulty1 fine concentrates1 as such1 require to be kept out of the blast-furnace charge1 either by subjecting the more siliceous material to a preparatory sintering process1 or by reserving the highly pyritic variety for roasting and subsequent reverberatory treatment4 ,references4 ,peters1 ,e4 ,d41 8,principles of ,copper ,smelting40 ,offerhaus1 ,c41 8,modern ,reverberatory ,smelting of ,copper ,ores40 ,eng4 and ,min4 ,journ41 ,june #ac1 #aijh1 pp4 #aahi-aaic2 ,june #bj1 #aijh1 pp4 #abcd-abcf4 ,ricketts1 ,l4 ,d41 8,experiments in ,reverberatory ,practice at ,cananea1 ,mexico10 and discussion1 ,trans4 ,inst4 ,min4 and ,met41 vol4 xix41 #aiji-aj1 pp4 #adg-ahe4 ,ricketts1 ,l4 ,d41 8,developments of ,cananea ,practice40 ,engineering and ,mining ,journal1 ,oct4 #gth1 #aiaa1 p4 #fic4 ,,lecture ,,vi4 ,,blast-,,furnace ,,practice4 ,functions of the ,furnace -- ,as ,melting ,agent--,reduction ,smelting -- ,oxidation in the ,furnace -- ,the ,pyritic ,principle -- ,features of ,modern ,practice3 ,water-,jacketing1 ,increase in ,furnace ,size1 ,external ,settling -- ,constructional ,details of the ,furnace4 ,the ,functions of the ,blast ,furnace4--,the functions of the blast furnace may be considered from three points of view3-- #a4 ,as a ,melting ,agent4 #b4 ,as a ,reducing ,medium4 #c4 ,as an ,oxidising ,medium4 ,in modern copper smelting practice1 the blast furnace is under ordinary circumstances never employed in the capacity of a reducing medium1 but is used for a variety of work in which its operations range from those of a melting furnace to those more particularly of an oxidising medium1 as its oxidising functions are becoming developed to a gradually increasing extent4 ,in the older processes of copper smelting1 when working on oxidised charges1 the melting and reducing functions of the furnace were exercised simultaneously2 when1 at a later stage1 sulphides were smelted in the charge1 the directly reducing function was utilised to a very much smaller extent4 ,in the reducing atmosphere then maintained inside the furnace1 the sulphides liquated and melted down without causing much concentration of the copper in the product1 elimination of sulphur being effected mainly by the direct action of heat on the pyritic constituents of the charge1 and by the interactions between the sulphides and the oxidised compounds of copper present4 ,when1 however1 increasing quantities of sulphide ore became available1 modifications in blast-furnace smelting practice were introduced with a view to increasing the concentration of the copper1 this being attempted either by preparatory roasting or by the addition of oxidised cupriferous materials to the charge1 sulphur being thus eliminated and some concentration resulting in consequence4 ,in such work the furnace chiefly exercised its melting function1 allowing1 as in the case of reverberatory working1 of the formation and thorough fusion of sulphide matte and silicate slag from the mixture of oxides and sulphides in the charge4 ,in the latest developments of practice1 the oxidation has been carried out to a continually increasing extent by the air blast at the tuyeres of the furnace4 #a4 ,the ,melting ,functions of the ,blast ,furnace4--,the blast furnace is under ordinary circumstances1 usually regarded as the cheapest of melting agents4 ,compared with the reverberatory1 the heat in the blast furnace is utilised more efficiently4 ,reverberatory working involves the passing of a flame over the surface of the charge1 and the transference of this heat through the mass depends upon the conducting power of the material itself1 which is1 however1 usually poor4 ,although the modern reverberatory practice of melting thin layers of preheated charge both from above and from below has greatly increased the efficiency of the furnace in this respect1 the closer contact of charge and fuel in the blast furnace allows of a more thorough communication of the heat4 ,the principal features of blast-furnace working which tend to make it the cheaper and more efficient agent for the treatment of cupriferous materials--with the exception of fines--are those of construction1 working1 and fuel economy4 7a7 ,the construction of the furnace is comparatively simple1 and it is not excessively expensive to erect2 furnaces and accessory plant can be purchased complete and easily set up and taken down again when required4 7b7 ,the furnace is elastic in its operation1 especially where the supply of material varies from time to time1 involving changes in the composition of the charge4 7c7 ,the furnace is readily started1 shut down1 and restarted at will1 and without much difficulty or additional expense4 7d7 ,the operation and smelting are rapid and cheap1 the capacity can be made enormously large2 all classes of material--except fines--such as ores1 slags1 and residues1 which accumulate to a considerable extent round a smelter1 can be conveniently dealt with directly1 whilst fines can now1 where necessary1 often be prepared into a suitable form for blast-furnace treatment4 7e7 ,the heat is more efficiently communicated to the individual parts of the charge1 in consequence of the more intimate contact of charge and fuel4 7f7 ,the fuel consumption is low1 the natural fuel values of the iron and sulphur on the charge can be utilised1 and the degree of oxidation 7and consequent concentration7 can be controlled in the furnace operation4 7g7 ,the furnace works continuously 7in modern practice the reverberatory furnace is also continuous in its action74 ,owing to the great elasticity in blast-furnace operation1 and its capability of dealing with practically every class of copper-bearing material in lump form1 modern practice is of the most diverse character4 #b4 ,the ,blast ,furnace as a ,reducing ,medium4--,in modern smelting practice1 with but a few exceptional instances1 a distinctly reducing atmosphere is avoided as far as possible4 ,this arises largely from the fact that the material available in modern work usually demands oxidation in order that satisfactory concentration may be effected4 ,in the early days of copper smelting1 however1 the reducing action was the chief function which was exercised1 mainly because at that time oxidised ores constituted an important part of the charge1 and a reducing action was required to obtain marketable products from such material4 ,at a later stage in the development of blast-furnace practice1 the sulphide ores which became available were roasted1 and the resulting oxidised products were subjected to reduction smelting1 in order to extract the metal4 ,on such oxidised charges1 blast furnaces were almost universally employed1 using carbonaceous fuel either in the form of coke or charcoal1 this material fulfilling the double purpose of fuel and reducing agent1 the excess carbon causing the reduction of the metal from the oxidised ore4 ,this operation was known commonly as 8black-copper smelting40 ,at the present time such oxidised ores are rarely met with in sufficient quantity by themselves to be worked by this method1 which involves also very serious losses in operation4 ,further1 such oxidised materials are in many cases valuable for smelting along with sulphide charges1 greatly assisting the concentration1 and it is usually advantageous to employ them in this manner4 ,the losses and difficulties in 8black-copper smelting0 are1 however1 of interest in so far as they apply to certain analogous problems in modern work4 ,these difficulties in reduction smelting arose largely from three causes3-- 7a7 ,losses of copper in the slag4 7b7 ,simultaneous reduction of iron with the copper4 7c7 ,chilling in the furnace hearth4 7a7 ,in the case of reduction smelting where sulphides are not present in any appreciable quantity1 the losses of copper may be either 7i47 ,as silicate1 or 7ii47 ,as metal4 7i47 ,sulphur is the natural protector of the copper in the furnace charge1 as1 owing to their powerful affinity1 a fusible1 fluid and dense product is formed1 which is very slightly soluble in slag2 and on this account1 a ready separation of the copper from the earthy materials can be effected4 ,so long as sulphur is present in moderate quantity there is little chance of copper entering the slag as silicate4 ,in reduction smelting1 however1 and especially in black-copper smelting where sulphur is lacking1 such losses are liable to occur1 since copper oxide is itself strongly basic1 and readily fluxes off with silica at high temperatures1 yielding silicates4 ,these products are less dense1 and are markedly soluble in the other silicates which constitute the slag2 moreover1 the copper oxides themselves are likewise partly soluble in1 and are readily carried in suspension by1 the silicate slags4 ,in order to prevent such losses as much as possible1 the reducing conditions in the furnace must be increased by the employment of more coke1 so as to ensure the reduction of the copper oxides and silicates4 ,these reducing conditions must not1 however1 be too drastic1 especially if the temperature of working be high1 on account of the great tendency to cause 7b7 a reduction of metallic iron1 which results in the formation of bears and scaffolds1 with their attendant difficulties of removal and their interference with working4 ,between these opposing causes of loss and difficulty1 a careful balance has to be observed in the smelting operations4 7,in modern practice1 losses of copper as silicate and oxide1 for reasons such as those detailed above1 occur to a marked extent in those operations where the sulphur is present in small proportions only1 and particularly where the reactions are intensely oxidising1 as in the furnace-refining operations and the later stages in the converter process4 ,the slags in such cases usually carry considerable quantities of copper in the form of silicate and oxide1 not infrequently to the extent of #bj to #cj per cent41 or even more4 ,the quantity of this slag is1 however1 kept as small as possible1 and copper in the material is readily recovered by the addition of these slags to the blast-furnace charge47 7ii47 ,losses of copper as metal also1 were formerly serious in black-copper smelting1 the metallic copper held in suspension in the slag being indeed the chief source of loss in this method4 ,the efficient separation of copper from slag1 especially in the small quantities formerly operated1 was therefore of importance4 ,satisfactory settling was1 however1 difficult of application1 since the behaviour of metallic copper is very different from that of sulphides4 ,it is much less fusible1 much less fluid1 and the small globules1 as reduced1 do not readily coalesce1 whilst the high temperatures favourable to good fluidity of the products and to good settling1 promote copper losses from the other causes noted above4 ,moreover1 the high melting point of the metal and its great conductivity added to the difficulties in providing suitable arrangements for settling1 since the copper not only tended to chill readily in any external settler1 but it was also very liable to do so in the crucible of the ordinary form of water-jacketed blast furnace1 such masses being exceedingly difficult to remove1 whilst the working of the furnace was necessarily much interfered with4 ,in order to conduct the necessary internal settling1 the older type of blast furnace was required1 in which water-jacketing near the hearth was dispensed with1 a large crucible bottom of non-conducting brasque or brickwork being employed instead4 ,such a form of furnace is not adapted to the modern methods of smelting where enormous capacity and output are essential1 whilst such a system of working interferes with the rapid and continuous smelting of large quantities1 to a greater extent than if the whole of the molten products are run out of the furnace continuously and the settling performed in an external vessel4 #c4 ,the ,blast ,furnace as an ,oxidising ,medium3 ,sulphide ,ores in the ,blast ,furnace4--,in modern blast-furnace practice1 the oxidising function of the furnace is the principal feature of working4 ,sulphide ores now constitute the chief source of copper1 and the smelting operations involve the oxidation of the accompanying constituents and the elimination of the resulting oxidised products4 ,such ores when smelted in the blast furnace with carbonaceous fuel1 and under the reducing conditions characteristic of the older methods of working1 would yield a product showing low concentration of the copper1 since the reducing conditions would largely retard the oxidation of sulphur which is an essential for the enrichment of the matte4 ,except for the sulphur eliminated from the pyritic constituents by the direct action of heat1 and a certain quantity by the interactions with oxides as already indicated1 the loss of sulphur would be slight4 ,the furnace under such circumstances would thus tend mainly to exercise its melting function1 and the result of such working would be the melting down and subsequent separation of the sulphides and slag1 with even less tendency to concentration than occurs in the reverberatory furnace1 where the atmosphere is less distinctly reducing4 ,the modern method of smelting sulphide ores being essentially an oxidising process1 it is necessary that oxygen be added to the charge with the object of promoting the elimination of the sulphur and iron1 and the consequent concentration of the copper4 ,this oxygen may be added in one of three ways3-- ,a4 ,addition of oxygen to the charge previous to the blast furnace smelting operation 7,roasting74 ,b4 ,addition of oxygen to the charge during the smelting operation itself4 i4 ,by adding oxidised materials to the charge 7,blast-furnace smelting with carbonaceous fuel74 ii4 ,by using the air blast of the furnace for oxidising the iron and sulphur1 thus at the same time utilising these elements as fuel and proportionately diminishing the amount of carbonaceous fuel required 7,the pyritic principle of smelting74 ,a4 ,roasting practice has already been discussed1 and the reasons for avoiding the operation where practicable1 on account of the expenses of an extra process1 the losses involved1 the fineness of the product1 and the loss of fuel values1 have been indicated 7,lecture ,,iv41 pp4 #ff-hj74 ,b4 i4 ,addition of ,oxidised ,charges in the ,blast ,furnace4--,the tendency for oxidised cupriferous materials to interact with sulphides finds useful application in copper smelting1 since it assists the concentration of the copper in the resulting mattes4 ,the principal reactions involved in this method are-- #b;,cu,o ,cu#b,s #d;,cu ,,so#b #b;,cu#b,o ,cu#b,s #f;,cu ,,so#b ,cu,s,o#d ,cu#b,s #c;,cu #b,,so#b whereby copper is produced and sulphur is eliminated as ,,so#b4 ,the liberated copper interacts with the excess of iron sulphide usually present in the furnace charge1 and enters the matte as sulphide1 whilst the iron which is thus set free is oxidised and carried into the slag as silicate1 the ultimate reactions being indicated approximately by the equation-- #b;,cu ,fe,s x,fe,s ,cu#b,s 4 x,fe,s 7matte7 ,fe 7oxidised and enters slag74 ,copper silicates readily interact with iron sulphides in the charge1 producing copper sulphides and iron silicates1 thus-- ,cu#b,o 4 x,si,o#b ,fe,s ,cu#b,s 7enters matte7 ,fe,o 4 x,si,o#b 7enters slag74 #f7;,cu,o 4 x,si,o#b7 #d;,fe,s #c;,cu#b,s 7enters matte7 #d7;,fe,o 4 x,si,o#b7 #bx,si,o#b7;enters slag7 ,,so#b4 ,all the above reactions lead to an enrichment of the matte in copper contents1 and at the same time1 to the transference of iron from the matte to the slag1 and although the conditions in the more reducing atmosphere of the coke-fed blast furnace are not so favourable to the fullest operation of these reactions as are the more neutral conditions of the reverberatory1 the addition of oxidised materials constitutes a valuable means of increasing the concentration in this method of smelting4 ,the blast furnace is thus also particularly suited for the recovering of the copper from the oxidised residues1 such as converter slags and scrap1 8calcine-barrings10 and the like1 which accumulate in very considerable quantities at a smelter1 and which by reason of their carrying much copper as oxide or silicate1 not only add their quota of copper to the products1 but materially assist the concentration and the furnace operation generally4 ,b4 ii4 ,the ,pyritic ,principle in ,blast-,furnace ,smelting4--,this is the most important principle introduced into modern blast-furnace smelting practice4 ,it has been evolved by the application of the results of experiments conducted from two different points of view--one series mainly on a laboratory scale1 the other from actual industrial practice4 ,starting from theoretical considerations1 ,john ,holway demonstrated by experiment that the heat of oxidation of the iron and the sulphur of pyritic copper ores was so great as to make their smelting a self-supporting operation under suitable conditions4 ,on the other hand1 within comparatively recent years1 smeltermen as a result of working practice1 have found that an increase of sulphides on the furnace charge has led to less and less carbonaceous fuel being necessary for the smelting operations1 providing that the conditions in the blast furnace be sufficiently oxidising4 ,in utilising these results for general blast-furnace practice1 the extended and successful application of this pyritic principle has led to marked advance in modern working4 ,the results obtained in a series of trials at the ,keswick smelter1 ,california1 are typical of such experiments on a practical scale1 and in spite of the two anomalous instances1 the general effects of the increase of sulphides in the charge are strongly marked 7see ,table ,,ix41 p4 #abj74 ,,table ,,ix4--,,effect ,,on ,,coke ,,consumption ,,of ,,increased ,,sulphur ,,in ,,the ,,furnace ,,charge 7,keswick ,smelter1 ,cal474 ,sulphur in ,charge4 ,coke ,consumption4 #fh per cent4 #aeg per cent4 #gg #afc #acf #ajb #agj #gg #aie #he #bbh #ga #bde #fh ,recent practice at ,anaconda affords another instance of the utilisation of the pyritic principle4 ,a large quantity of the ore available 7known as second-class ore7 requires wet dressing before it can be treated most profitably at the furnaces1 and the operation thus produces considerable quantities of sulphide concentrate1 of which a moderate proportion is coarse--well suited for blast-furnace treatment4 ,the charge if submitted to reduction smelting with carbonaceous fuel1 would yield a matte too low in copper contents for immediate converter treatment1 since there is not available a sufficient supply of oxidised cupriferous material to effect a high enough concentration for the direct production of a converter-grade matte4 ,instead of roasting so as to reduce the sulphur contents to the required degree1 and then smelting with the usual amount of carbonaceous fuel1 the pyritic principle has been utilised to the fullest possible extent1 by smelting the raw charge containing as much of the coarse concentrate as is available1 with a strongly oxidising blast1 thus effecting the desired concentration1 and occasioning the use of a lower coke proportion than would otherwise have been necessary4 ,by gradually increasing the sulphide on the charge until the sulphur proportion reached #h to #i per cent41 the coke consumption was reduced to about #aa to #ab per cent4 ,during the past two or three years the advantages of introducing more and more sulphide have become so apparent1 that increasing quantities of inch concentrates are being included in the charge1 and although such material is exceedingly difficult to deal with in the blast furnace1 the advantages arising from its use outweighs the trouble it causes in actual working4 ,by this further increase of the sulphur proportion1 from the former #h to #i per cent4 up to #aa to #ab per cent41 the coke consumption has been steadily reduced until it now amounts to about #i per cent4 only4 ,the fuel value of the iron and sulphur is augmented at a rate much greater than their actual increase in numerical proportion would suggest1 on account of the much higher calorific intensity of large and massive quantities of fuel burned at once than that resulting from smaller amounts disseminated throughout a mass of inert material such as gangue4 ,the practical application of the pyritic principle to blast-furnace practice thus involves the employment of the furnace as a medium for conducting the required oxidation of the charge1 as a result of which1 the heat of this combustion proportionately reduces the amount of carbonaceous fuel required for the smelting and separation of the products1 whilst at the same time the desired concentration is also effected4 ,the basis of such working is1 therefore1 the powerful oxidising action within the furnace itself1 and the fullest utilisation of the heat resulting from this oxidation of the sulphides4 ,in order to supply the heat necessary for the reactions and fusions of smelting1 a definite quantity of fuel is essential in the furnace4 ,in those cases where the proportions of sulphide are not sufficient to supply the required amount1 a supplementary quantity of coke fuel becomes requisite4 ,the extent to which coke is necessary for the smelting operations decides whether the process may be termed 8true pyritic0 or 8partial pyritic0 smelting4 ,in the former case1 the coke allowance may be reduced to such small proportions that its influence in the smelting zone of the furnace is practically negligible4 ,in partial pyritic smelting1 coke is necessary to the extent of supplementing the heat derived from the sulphide fuel1 and the proportion employed in modern work is reduced to the lowest possible quantity4 ,not only is economy in coke allowance one of the chief essentials in furnace management1 but the presence of a larger amount than is absolutely necessary decreases the efficiency of the smelting operations1 since1 owing to its reducing action and its consumption of the oxygen in the air blast which is to be utilised for the combustion of the iron and sulphur1 the concentration of the copper in the resulting matte would be decreased4 ,the extent to which the pyritic principle may be operated in actual working depends in the first instance upon the nature of the charge itself1 especially upon the relative proportions of copper1 iron1 and sulphur1 and on the quantity of gangue4 ,since these vary in the ore supply of different localities1 the extent to which the principle may be applied and the coke consumption be reduced1 will be subject to alteration accordingly4 ,thus in the case of an ore which contains such proportions of these constituents as would on simple melting yield a matte of converter grade1 the pyritic effect in the furnace would necessarily be very small1 and the smelting would be almost entirely a melting operation requiring from #aj to #ae per cent4 of coke on the charge1 even though the sulphur contents of the charge be high4 ,ores and charges of such a composition are1 however1 rarely met with in modern practice1 the ratio of copper to iron sulphides usually being low4 ,on the other hand1 in the case of an ore consisting largely of iron sulphides with but little copper--i4e41 a massive low-grade pyritic ore--the pyritic effect in the furnace might reach a maximum1 and the coke required on the charge be reducible to very small proportions4 ,such material is well suited for true pyritic smelting4 ,hence modern practice ranges from the true pyritic smelting1 where pyritic fuel is principally employed1 through varying degrees of partial pyritic smelting1 where the pyritic fuel is supplemented to the required degree by coke1 to reduction smelting1 relying mainly on carbonaceous fuel for the necessary heat supply4 ,in all cases1 the object of the operation is to oxidise inside the furnace so much sulphur and iron as is necessary to yield a matte product of converter grade1 utilising the natural sulphide fuel values of the material so as to reduce to the lowest possible proportion the quantity of coke required4 ,features of ,modern ,practice4--,apart from the applications of pyritic smelting1 which will be considered separately1 three features of great importance have been introduced into modern blast-furnace working4 ,these involve3-- ,a4 ,the practice of water-jacketing the furnace4 ,b4 ,the development in the size of the furnace4 ,c4 ,the practice of external settling4 ,illustration3 ,fig4 #cb4--,modern ,blast-,furnace ,shell of ,sectioned ,jackets 7,p4 ,m4 ,m4 ,co474 ,a4 ,the ,practice of ,water-jacketing4--,the evolution of the blast furnace from the primitive hole-in-the-ground form to the modern type may be rapidly sketched4 ,in its early stages1 the development was carried out mainly on the ,continent of ,europe1 following the course of the enclosing of the charge in shafts which became of gradually increasing height1 the introduction of blast through tuyeres near the bottom of the shaft1 and the arrangements for collecting the molten materials in the hearth1 and for tapping4 ,by the year #ahej a typical form of furnace was represented by the ,mansfeld pattern1 which consisted of a rectangular firebrick shaft enclosed by massive stonework4 ,at the lower extremity was a hearth constructed of refractory material1 usually of brasque--a mixture of fireclay and coke--well tamped down4 ,the dimensions were from about #b feet to #b feet #f inches broad1 #ad feet to #af feet high1 with two tuyeres of #a to #b inches diameter1 supplying blast at #d to #aj inches water pressure2 the capacity of such a furnace being about #d tons per twenty-four hours4 ,it is of interest to note that this form of furnace possessed arrangements both for internal or external settling of the products1 the usual practice being1 however1 to allow the smelted material to collect and settle in the hearth4 ,in endeavouring to increase the capacity of the furnace and the rapidity of working1 as well as to ensure efficient settling of the products1 it became necessary to maintain a high temperature in the lower parts2 but in consequence of the excessive heat and the corrosive nature of the molten materials1 the most refractory brasquing available was rapidly attacked1 and the necessity for adopting means to prevent the destruction of the furnace linings became apparent4 ,the use of water-jacketing for this purpose had long before been applied to certain branches of cast-iron refining1 and in #ahge the ,piltz water-jacketed blast furnace was introduced for the smelting of lead ores4 ,this form of furnace was circular in horizontal section1 and the boshes consisted of two concentric shells between which a stream of water circulated4 ,this principle was quickly adopted for the purposes of copper smelting furnaces1 although modifications were found to be necessary in certain particulars before perfectly successful working was achieved4 ,owing to the higher temperatures prevailing in the furnace1 the height to which the water-jackets were carried required to be increased1 and it was chiefly when the rectangular form of furnace was introduced that the thoroughly successful application of water-jacketing was accomplished4 ,this feature in blast-furnace work was rapidly and very successfully developed by the ,american copper smelters when the new establishments in the ,west were opened up1 and the substitution of the older form of lining by metallic water-cooled jackets1 which in comparison are practically indestructible1 immediately led to an enormous improvement in smelting practice4 ,the modern blast furnace is essentially a water-jacketed shell from charging floor to base plate1 rectangular in plan1 and completely sectionised4 ,many of the advantages of such a furnace construction are apparent1 and have been referred to in discussing the furnace as a melting agent4 ,the salient features of the modern water-jacketed furnace are3-- 7i47 ,water-jacketed furnaces are planned1 constructed1 and erected simply and with ease4 7ii47 ,the first cost of the furnace1 making allowance for excavation and foundations1 is not unfavourable to the water-jacketed furnace1 whilst the ease of fitting and the interchangeability of parts due to sectioning1 reduce the costs of erection4 7iii47 ,the convenience and simplicity in operation of the water-jacketed furnace are very marked1 whilst the permanence in the shape tends to greater uniformity of working and to ease of management4 7iv47 ,accretions and the general difficulties of working are readily dealt with and controlled1 barring and other operations being more conveniently conducted4 7v47 ,the repairing of water-jacketed furnaces is rendered very simple1 cheap1 and rapid in operation1 the principle of sectionising1 allowing of the ready removal or replacement of the jackets for repairs2 the saving in time1 labour1 and general expense being particularly marked4 7vi47 ,the elasticity of the furnace1 both as regards size and management1 has been enormously increased1 and the successful extension and working of the large modern furnaces have only become possible with the adoption of this feature4 7vii47 ,water-jacketing has allowed of the rapid driving of furnaces1 leading to an enormous increase in the output per square foot of hearth area1 by permitting intense heating inside the furnace1 and rapid withdrawal of the molten products4 ,the chief consideration affecting the adoption of water-jacketing in any locality might be the scarcity or unsuitability of the water supply1 which may necessitate a choice between the employment of brick furnaces1 or the crushing1 roasting and reverberatory treatment of the ore4 ,in cases where the water supply is not well suited for jacketing purposes1 settling or other preliminary treatment of the water might be required4 ,the former objection to water-jacketing on the assumption of valuable heat being carried away by the jacket water1 thus involving a waste of fuel1 has proved to be groundless in practice2 with good management such heat losses are smaller in amount and less damaging in effect than those due to radiation from highly heated brick walls1 quite apart from the actual necessity for such jacketing in modern furnace construction1 even had such losses been marked4 ,b4 ,the ,development in ,furnace ,size4--,the blast furnace increased but slowly in size during the nineteenth century up to #ahej1 and the dimensions of the most advanced type did not exceed #d feet by about #b feet #f incites internally at the tuyere level1 the capacity being about #d tons per day4 ,furnaces at this period were usually square or circular in section4 ,illustration3 ,fig4 #cc4--;,blast ,furnaces under ,construction1 showing ,fixing of ,jackets1 ,bottom ,plate1 ,method of ,support1 ,sectioning1 etc4 7,t4 ,e4 ,co474 ,the size of such furnaces was largely dependent on the penetrating power of the blast1 and a slight increase in cross-section resulted gradually1 as improvements in the mechanical contrivances for producing blast were developed4 ,this1 however1 soon reached a limit1 owing to the difficulties in making the blast penetrate to the centre of the charge in the wider furnaces1 and to the disproportionate costliness and increased working difficulties attendant on such practice4 ,it was further found that the high pressure required in order to force the blast through an increased width of charge produced an intense local heating effect against the tuyeres1 resulting in high slag losses and low concentration on smelting1 whilst the consumption of fuel was much increased4 ,an important modification in blast-furnace design was introduced in #ahfc1 when the principle of increasing the size of the furnace in direction of its length1 whilst maintaining the width which had been found best suited to economical working1 was applied by ,rachette4 ,this was first intended for the purposes of lead smelting1 but the principle was quickly recognised as having important applications to copper smelting practice1 and was readily adopted and developed4 ,it has become the basis of all subsequent modern copper blast-furnace design1 and the gradual increase in dimensions up to the enormous blast furnaces with huge outputs of the present day has been made by extending the length whilst maintaining a relatively small width4 ,for some time development proceeded along these lines slowly and with much caution1 chiefly owing to the difficulties anticipated in the management of such large units4 ,up to #ahhe1 the largest blast furnace 7at the ,parrott ,smelter1 ,butte7 was but #h feet long by #cf inches wide2 by the year #aijj the dimensions had reached #aj feet by #db inches4 ,subsequently1 under the direction of the remarkably enterprising management of the ,washoe ,smelter at ,anaconda1 a wonderful era of furnace extensions was commenced1 and is indeed1 still undergoing development4 ,illustration3 ,fig4 #cd4--;,development of the ,blast ,furnace 7,gowland74 ,here in #aijb1 blast furnaces #ae feet long by #ef inches wide were erected1 the plant eventually consisting of seven such furnaces built in a straight line1 and situated #ba feet apart from each other4 ,a largely augmented ore supply subsequently coming to the smelter for treatment1 an increased furnace capacity was required1 for which only a very limited suitable space was available4 ,mr4 ,e4 ,p4 ,mathewson1 the smelter superintendent1 determined upon attempting the revolutionary idea of joining up two of the #ae-;foot furnaces by bridging over the #ba-;foot space between them1 and continuing the vertical side water-jackets across this space1 thus forming a furnace #ae #ba #ae1 or #ea feet in length4 ,no work on such a large and boldly conceived scale had ever been attempted before1 and many difficulties in construction and operation were anticipated4 ,mathewson first conducted a series of constructional trials1 and found in the first instance that by taking suitable precautions1 it would be possible to carry out these changes whilst the furnaces themselves were running4 ,it was found that it was possible to remove or replace single jackets without shutting down the furnace1 by the device of forming a crust against such a jacket1 of sufficient thickness to bear the weight of the charge for the short period of time during which the change was being made4 ,such a crust is readily obtained by shutting off the tuyeres in the particular jacket and in its neighbours1 and maintaining a rapid stream of cold water through these jackets4 ,further1 it was found that any desired portion of the sides or hearth of such a long furnace could be well barred and cleaned whilst the rest of the furnace was in operation1 whereas such barring and cleaning on a small furnace seriously interrupted the working1 and reduced the capacity4 ,the preliminary tests being satisfactory1 the necessary constructional work was carried out whilst the two furnaces were in blast2 the inner end jackets of these furnaces were taken down1 and in a short time the new #ea-;foot furnace was in regular operation1 and proved so remarkably successful that two other pairs of furnaces were similarly joined up4 ,in the following year a still further great extension was made by joining up in a like manner the end #ea-;foot furnace to the last remaining #ae-;foot furnace1 by again bridging over the intervening #ba-;foot space1 thus constructing a furnace of the enormous length of #ea #ba #ae1 or #hg feet4 ,it was at one time intended to carry this progress still further by joining up the other two #ea-;foot furnaces1 so as to make a single one #abc feet in length1 but certain difficulties in the matter of bringing coke supplies to the two sides1 under the special conditions of available floor space1 and the disastrous effects of the financial panic of ,october1 #aijg1 stopped all extension work for the time4 ,such extensions would however1 present no real difficulties either in construction or in subsequent furnace management or operation4 ,figs4 #ce and #cf indicate in plan and elevation the arrangement of the plant and accessories for these extended furnaces4 ,each #ae-;foot furnace had its own settler situated in front1 and these have been retained without any change of position or any further additions4 ,the hearth of the newly bridged portion slopes from the middle of the bridge to the tap-holes of the old furnaces1 which still serve this purpose for the larger ones1 and from which a continuous stream of matte and slag flows through a slag spout to the settler in front4 ,the side water-jackets of the old furnaces remain1 being built up in two sets of panels1 each #g feet #f inches wide1 whilst the new bridge portions are constructed of three sets of jackets1 each #g feet wide4 ,illustration3 ,fig4 #ce4--,plan of #ea-;foot ,blast ,furnace1 ,anaconda1 indicating ,position of ,crucibles1 ,spouts1 and ,connecting ,bridge between ,old ,furnaces4 ,illustration3 ,fig4 #cf4--,longitudinal ,section and ,part ,elevation of #hg-;foot ,blast ,furnace1 ,anaconda1 indicating ,crucibles of ,old ,furnaces1 ,bridge1 and ,jacketing4 ,the furnaces in their lengthened form have proved a tremendous success1 far indeed beyond the anticipation of the designers and managers4 ,this is largely due 7a7 ,to the increased efficiency and economy of replacing a number of smaller furnaces situated end to end by a single large furnace2 7b7 ,to the increased intensity of heat and reactions owing to large massed quantities of fuel burned at once1 and to large masses of material being smelted and in a state of chemical activity4 ,the advantages which result from such lengthening of blast furnaces are3-- 7i47 ,gain in hearth area without extension of the blast-furnace floor and building4 7ii47 ,increase in smelting or hearth area and in consequent capacity1 at a rate very much superior to the extra water-jacketing involved4 ,thus1 in the #ea-;foot furnace1 the capacity has been increased in the proportion of #ch to #a1 the jacketed surface has increased only at the rate of #bd to #a4 ,the output has increased at a much greater speed than was actually anticipated from the additional hearth area4 7iii47 ,a very marked saving of fuel4 ,the amount of coke required for similar charges has been reduced by one-tenth2 more than #aa per cent4 was required formerly on a charge1 only #aj per cent4 was necessary under the new conditions4 7iv47 ,the rapidity of working of the furnace has increased owing to the effect of the narrow width and small crucible dimensions as compared with the length4 ,this has caused a more rapid flow through the furnace slag-holes1 thus preventing the formation of obstructions1 and tending to wash out any which might threaten to stick4 7v47 ,higher furnace temperatures result1 and both slag and matte are hotter than in smaller furnaces4 ,in consequence more siliceous slags can be run1 thus saving the cost of the fluxes which might otherwise be necessary4 7vi47 ,marked decrease in incrustation4 ,crusting is most likely to occur at points where the smelting activity is lowest1 and in the cooler parts of the furnaces1 such conditions being usually prevalent at the corners1 where the shape also assists in the holding up of material4 ,crusting is one of the chief troubles to be prevented and overcome in operating the blast furnace4 ,the elongated furnace of #hg feet length practically takes the place of five shorter ones1 representing no less than #bj corners and #aj end jackets2 the new furnace thus reduces the opportunities for crusting at least five-fold4 ,in this way the hearth area has been very greatly increased1 with still but two ends to hold crusts4 ,the long furnace-walls with their ends so far apart1 in addition1 offer much less opportunity for the formation of crusts than do the side walls of shorter furnaces1 accretions obtain little support1 and often tend to break down under their own weight1 whilst they can be more readily removed by barring1 on lowering the height of the furnace charge for a time4 7vii47 ,the elasticity of the furnace operations has been much increased4 ,in short furnaces1 cleaning and barring for the removal of obstructions1 etc41 necessitate the shutting down of the unit1 often a complete taking down of the furnace-walls and their subsequent replacement1 followed by a re-starting of the furnace work4 ,the ideal in modern work is continuous running of the unit4 ,the larger furnaces allow of such practice1 since they can be kept in operation whilst a particular portion is undergoing cleaning or repair4 ,as stated above1 the elongation of the furnaces themselves was conducted whilst the older #ae-;foot portions were working4 ,leaky or worn-out jackets or spouts are readily removed without serious interference with the working of the rest of the furnace1 and this operation usually requires a few hours only4 7viii47 ,the charge may be varied in different parts of the furnace to suit special requirements1 without interfering with the general operations4 ,thus1 suitable additions for the smelting out of crusts1 or variations in the charge to reduce corrosion near the #ba-;foot bridge1 can be effected whilst the furnace is running as usual4 7ix47 ,increased flow of material through the settlers is effected without decreasing the efficiency of the settling4 ,each settler now serves #be feet of furnace-hearth length1 instead of the #ae feet of the smaller furnaces1 and in spite of the more rapid passage of the materials1 the settling is actually better and the resulting slag cleaner1 owing to the higher temperatures of working and the consequent greater liquidity of the products1 whilst the settler is also hotter4 ,thus the greater output of material has required no extra labour or construction on the tapping floor1 though tappings are now more frequent4 7x47 ,the labour costs per ton of furnace capacity are greatly reduced1 as are also the operating and management costs1 since such labour and control are to a large extent dependent on the number of units comprising the plant4 7xi47 ,the initial cost1 per ton of furnace capacity1 is also much reduced4 ,in the elongated furnace1 the settlers have not been added to1 the old slag notches only are required to do duty as before1 and the older equipment for bracing and trussing provides for much of that required in the extensions whilst the original building itself served for the housing of the increased furnace area4 7xii47 ,further extension of the furnace length is readily possible if desired4 ,the older #ae-;feet furnaces had a smelting capacity of #ef tons per square foot of hearth area per day1 those of #ea feet length smelt on an average #fgb tons per square foot daily1 whilst the output of the #hg-;foot furnace amounts to #c1jjj tons of material daily1 corresponding to #c1jjj #hg feet #d feet #h inches1 or about #ge tons per square foot of hearth area4 ,whilst this particular smelter is of course unique in the dimensions1 equipment1 organisation and management of its plant and the magnitude of its operations1 and though at most modern smelters the ore supplies and smelting conditions do not admit of the introduction of such enormous units2 at the same time the principles which underlie the great advantages of the longer form of blast furnace have had an important influence on blast-furnace equipment and design generally4 ,the constructional details of these large furnaces are1 for the most part1 common to all modern blast furnaces2 it is mainly the size and capacity which are exceptional4 ,the usual length adopted at smelters with more modest output varies from about #ae to #be feet1 with a smelting capacity of from about #djj to #hjj tons per twenty-four hours1 depending naturally on the working conditions4 ,c4 ,the ,practice of ,external ,settling4--,in connection with modern blast-furnace practice1 the feature of external settling is of much importance1 its adoption having had a marked influence on3-- 7a7 ,the efficiency of separation of the smelted products1 and the production of clean slags4 7b7 ,the output1 and rapidity of working of the furnace4 7c7 ,the control and organisation of the smelting processes4 7a7 ,the function of the blast-furnace plant is the concentration of the values into a matte of correct grade for further treatment1 and the production of a slag which is sufficiently clean--that is1 free from copper and other values--to allow of its being disposed of as waste1 immediately4 ,numerous factors decide the copper contents of the slag which is economically the cleanest--the general average is about #jbe to #jce per cent4 of copper4 ,the actual condition of the copper in the slags is a matter of some uncertainty1 and it does not appear improbable that very small quantities of sulphides may actually be in solution in the silicate slags4 ,the general consensus of opinion1 however1 favours the view that much of the copper which is present exists in the form of minute shots of the matte1 actually held in mechanical suspension1 and this is certainly the case when the copper contents exceed the limits stated above4 ,in consequence1 it is frequently noted in practice that the copper in the slag increases with the grade of the matte4 ,the question has been reviewed by ,l4 ,t4 ,wright who suggests some actual solubility of matte-products in the slag4 ,wright's curve indicating the connection between matte-grade and slag values is reproduced in ,fig4 #cg4 ,this connection might however1 possibly result from the fact that the individual shots of matte are themselves higher in copper contents1 since it may be assumed that in fairly clean slags practically the same number of shots are held up1 owing to the forces of capillary attraction and surface tension1 and that the increased density of the higher grade mattes would influence but slightly their downward settling when in such a fine state of division4#aa ,illustration3 ,fig4 #cg4--;,copper ,contents in the ,slags accompanying ,mattes of ,various ,grade4 ,the molten products of the blast-furnace operation are separated by the settling of the matte and slag under the action of gravity1 and the production of the economically cleanest slag depends upon the fulfilment of those conditions which allow of the most perfect downward settling of the small particles of matte4 ,the three main requirements for efficient settling1 apart from the composition of the slag1 are3-- 7i47 ,sufficiently high temperature4 7ii47 ,opportunities as regards time1 rest1 and space for quiet settlement4 7iii47 ,large masses of heated products4 ,in each of these essentials1 the method of external settling1 as now conducted at modern smelters1 best satisfies the conditions required for successful work4 ,the present practice is to make no attempt to conduct settling in the blast furnace1 but to run the products through and out of the furnace with the greatest speed attainable1 and to allow the matte and slag sufficient time and opportunity to settle and separate in some independent and external vessel1 which stores the matte and allows the clean slag to run straight away to waste4 ,the former method of inside settling gave rise to many difficulties in practice1 but objections were urged against the external settler1 to the effect that heat might be wasted by the abstraction of hot materials from the furnace to an exterior vessel1 and that the settling would not be efficiently conducted outside1 as in the very hot interior of the smelting furnace4 ,modern practice has proved conclusively that both objections are groundless4 ,such heat as is carried away by the continual stream of molten material can usually be well spared in the modern plant1 which is driven so rapidly that an abundant supply of exceedingly hot matte and slag pass through to the settler1 whilst the results of every-day working demonstrate the efficiency of the external settler1 which cannot be equalled1 far less surpassed1 by any method of inside settling1 under modern smelting conditions4 ,thousands of tons of slag pass daily through the settlers1 clean enough to discharge straight to the dump1 the copper contents rarely exceeding #jdj per cent4 7b7 ,the modern conditions of rapid working and large output render the use of external settlers practically essential1 owing to the double work of smelting and separating being no longer confined to one and the same vessel4 ,the aim in present practice is to exercise the smelting function only of the furnace1 and to do so to its fullest capacity1 smelting for matte of the desired grade as rapidly as possible1 and therefore running the products through the furnace in a constant rapid stream and allowing them to settle quietly outside4 ,under these circumstances the furnace itself smelts most economically and efficiently4 ,it will be recalled that present-day practice involves the subsequent treatment of the fluid matte--product in the converter1 so that whilst the former methods of working might have possessed certain advantages for the settling and storing of matte in the small furnaces1 and then tapping out and casting into cakes for subsequent treatment1 such methods have practically no application to modern systems of working4 ,internal settling almost invariably leads to the accumulation of debris1 of chills and of any infusible masses of material which may be produced in the furnace1 occasioning delay in the operations1 waste and difficulty in working1 and so interfering seriously with the speed and continuity of the smelting1 as well as decreasing the output of the furnace4 ,on the other hand1 a rapid flow of hot molten material through the furnace not only tends to prevent this formation of chills or accretions1 but greatly assists in the dissolution or removal of such as might be formed4 ,should the production or collection of such masses be transferred to the settler instead1 they are more readily attacked and remedied without interfering with the continued operation of the furnace4 ,further1 the nature of the hearth which would be most satisfactory for internal settling is not at all suited for modern smelting conditions4 ,the ordinary water-jacketing would have too marked a cooling effect on the hearth for the materials to remain sufficiently hot and fluid to allow of proper settling1 whilst a brasque or similarly lined hearth suitable for such settling would1 under the present conditions of rapid driving and intense reactions1 be unable to withstand the highly corrosive and abrasive action to which it would be subject1 so that breakouts1 necessitating delays and repairs1 would constantly occur4 ,water-jacketing in this portion of the furnace is indeed an essential for modern conditions1 and consequently rapid driving and quiet internal settling in the same area are quite incompatible4 ,the modern fore-hearth1 on the other hand1 is accessible and easy of repair1 and in the event of any trouble occurring therein1 the furnace itself can continue its smelting activity to the full1 since other suitable arrangements can readily be made for temporarily dealing with the products4 ,illustration3 ,fig4 #ch4--,water-,jacketed ,blast ,furnace 7#dh inches by #bdj inches74 ,lower ,portion1 indicating ,air and ,water ,connections1 ,bottom ,supports1 ,end ,slag ,spouts1 etc4 7,p4 ,m4 ,m4 ,co474 7c7 ,the functions of the blast furnace in the modern smelting scheme are particularly dependent upon the employment of the external settler in conjunction with it4 ,the work of the furnace plant is to produce as rapidly as possible1 a supply of suitable grade matte for the converters2 large quantities of hot fluid matte must be available at a moment's notice1 and such demands are often very erratic1 being dependent on the working of the converter plant and the refining furnaces4 ,it is essential to the successful operation of the blast furnaces that the manager should be in a position to work his furnace as rapidly and continuously as possible1 which is best attained by making the output independent of irregular tappings of matte just when required by the converter department4 ,the settlers1 in exercising the function of reservoirs for matte1 from which the converter department may draw at will1 allow of regularity of working and rapidity of output in a manner possible in no other way4 ,the only alternative1 using internal settling1 would consist of tapping out matte at regular intervals and casting such material when it is not immediately required1 a wasteful and unnecessary practice incompatible with modern ideas of smelting work4 ,during the early stages of the development of smelter plant1 the use of reverberatory fore-hearths received considerable attention1 the principle being to build a fire-box in communication with the settler1 so as to ensure a sufficient supply of heat in the vessel for efficient settling4 ,modern furnaces however1 usually supply a large enough quantity of very hot and fluid matte and slag as to allow of very efficient separation without the use of extra heating1 providing the position and construction of the settler is suitably planned1 as will be described in due course4 ,the ,construction of the ,blast ,furnace4 ,dimensions4--,the modern blast furnace is a long1 narrow1 water-cooled shell1 rectangular in plan4 ,the dimensions1 particularly the length1 vary greatly1 being regulated according to the anticipated output of the furnace-unit4 ,the size is generally expressed in terms of the internal dimensions at the tuyere level1 which represents the smelting area4 ,the width of the modern furnace varies usually from #dd to #ef inches1 according to the blast pressure1 method and speed of working1 concentration to be effected1 and so forth4 ,the length in many cases is between #ae and #be feet1 when the furnace may be conveniently worked in connection with one large settler4 ,the capacity of such a unit naturally depends on the conditions of working2 it may be taken roughly as from #d to #f tons of material per square foot of hearth area per twenty-four hours4 ,foundations4--,the furnaces are built upon a foundation which is necessarily very strong1 being usually either of solid rock or of concrete4 ,bottom ,plate4--,the bottom plate of the furnace usually carries part of the weight of the lower tier of water-jackets as well as the furnace burden1 and is supported1 some distance above the ground1 on screw-jacks leaving an air-space below the furnace1 which allows of convenient access for repairs or adjustment4 ,the height of the construction is thus raised to a convenient distance for adjustment to the discharge to the settlers4 ,the bottom plate should consist of sectionised water-cooled cast-iron plates bolted together1 with a thin layer of brickwork placed above1 to protect them from the corrosive influences to which they are subject4 ,there is a slight slope towards the slag-notch4 ,the actual working bed of the furnace is however1 a chilled crust of material which sets on this bottom owing to radiation below1 and which1 when suitable precautions have been taken1 usually adjusts itself naturally whilst the furnace is in operation1 by what may be termed automatic radiation4 ,thus1 apart from the water-cooling devices1 if the working bottom wears down towards the metal plates1 the loss of heat by radiation through the thin layer of material causes a chilling effect which leads to a thickening of the crust4 ,should the crust thicken unduly and so threaten to interfere with the discharge1 the radiation is decreased owing to the thickness2 and the high temperature which prevails upon this layer causes a partial melting so that it gradually becomes thinner again--thus regulating itself for the most part automatically4 ,illustration3 ,fig4 #ci4--,tapping ,breast of ,blast ,furnace1 ,cananea 7see p4 #aci74 ,illustration3 ,fig4 #dj4--,riveted ,steel ,water-,jacket1 showing ,tuyere ,holes and ,water ,inlets1 etc4 7,p4 ,m4 ,m4 ,co474 ,illustration3 ,fig4 #da4--,transverse ,section through ,modern ,blast ,furnace1 showing ,arrangements of ,boshed ,lower ,jackets1 ,upper ,jackets and ,plates1 ,stays and ,supports1 etc4 ,illustration3 ,fig4 #db4--;,interior of ,anaconda ,blast ,furnace1 showing ,jacketing1 ,tuyere ,holes1 and ,bridge4 ,water-,jackets4--,the usual height of the modern furnace1 as reckoned from tap-hole to charge floor1 is roughly from #ad or #af feet up to #bj feet1 water-jacketed all the way4 ,the sides and ends of the furnace are constructed of sectionised water-jackets arranged horizontally in tiers and vertically in panels4 ,there are usually two1 occasionally three1 tiers1 suitably stayed and supported4 ,the practice as regards the shape and arrangement of the jackets varies greatly4 ,it was formerly not uncommon to work with three tiers of jackets for the sides2 of these the lower tier extended only from the sole-plate to the level of the slag-notch1 forming practically the crucible jackets1 the height varying from #b feet #f inches to #d feet4 ,these were most used when the discharge to the settler was situated at the side wall of the furnace4 ,above these jackets was situated the second tier through which the tuyeres passed2 these build up the boshes of the furnace1 and are termed the 8bosh0 or 8tuyere0 jackets4 ,in most modern furnaces these two tiers of lower jackets are replaced by one set of panels of from #g to #aj feet in height1 the jackets being given a slight slope towards each other at the bottom1 so as to form a very small bosh angle2 the contraction is about #h inches4 ,this improvement does away with a good deal of the jointing otherwise necessary near the hottest parts of the furnace1 and thus lessens the danger of leakage at these points4 ,the water-cooled breast-plate containing the opening for the escape of the products is now put in position as a separate piece1 well secured to the rest of the jacketing 7,fig4 #ci74 ,above the lower tier of jackets is placed the upper series1 often from #g to #i feet in height1 which carries the walls of the furnace up to within a few feet of the charging platform4 ,these jackets are parallel1 and no bosh is given 7see ,fig4 #da74 ,the end jackets are usually built in two tiers only1 the upper1 #g feet to #g feet #f inches1 as a rule1 and the lower1 #h feet to #i feet #f inches1 according to circumstances2 in the smaller furnaces the end wall may sometimes consist of a single jacket only4 ,they are vertical1 no end bosh being allowed4 ,the end jackets are each single panels1 whilst the side walls are built up in panel sections1 the width of which vary1 but are often #g feet to #g feet #f inches wide1 the panels being bolted or clamped together and strongly stayed4 ,the water-jackets are constructed of flanged steel plate1 the inner sides of which are #e_/af to inch thick1 the outside to #e_/af inch4 ,the seams are flanged outwards1 so as to prevent joints1 etc41 being exposed to the inside of the furnace4 ,the water space between the two plates of the jacket is from #c to #d inches4 ,it is usual to support the weight of these jackets on ,i-beams carried by the upright columns2 very strong bracing and tieing is also necessary in order to prevent the side walls from bulging by the great pressure to which they are subjected4 ,in order to protect the jackets themselves from buckling by the forces acting upon them1 they are strengthened inside the water space by a series of 8 bands1 which run vertically downwards between the plates1 and are rivetted to the outer side--this device is found not to interfere unduly with the proper circulation of the water4 ,leakage between the joints of the separate jackets is prevented by asbestos packing4 ,in spite of the strong binding and bracing of the walls in this manner1 the connections are so devised as to allow of their being unfastened very easily1 so that jackets may be readily disconnected and taken down when it becomes necessary to do so4 ,arrangements for the water supply to the jackets vary considerably4 ,in localities where a plentiful supply is available1 each jacket has its independent outlet and inlet pipes2 in other cases it is common to arrange an independent feed to each set of panels1 water being supplied first to the jackets of the lower tier1 and being discharged from them to the jackets situated above4 ,the supply pipes for the various jackets branch from water main pipes running at the sides of the furnace4 ,the tuyere or bosh jackets are pierced horizontally at intervals of about #a foot1 with a line of #e-to #g-;inch holes for the fitting in of the tuyere pieces4 ,these are formed of steel thimbles1 of -inch metal1 which have a slight taper1 fitting secured against the inner plate and rivetted to the outer one1 thus allowing of ready replacement when necessary 7see also ,fig4 #dj74 ,above the side jackets of the furnace there is usually a heavy mantel-plate1 #b feet to #b feet #f inches high1 with a sloping front1 and surmounting this are apron plates1 #a foot #f inches to #b feet high1 inclined at #de1 constituting a hopper which directs the charge towards the centre of the furnace in such a way as to keep the fines nearer to the middle line1 and thus leave the sides of the charge more open1 in order to ensure more regular working4 ,superstructure4--,the jacketing1 together with the apron and mantel plates carry the structure up to the charging floor4 ,above this is the superstructure with the arrangements for taking off the furnace gases1 and for the feeding of material for the charge4 ,in many cases the general practice still prevails of constructing the walls of this portion of brickwork1 often about #ad feet high1 surmounting this with a hood of metal from the top or sides of which large off-takes carry the furnace gases to the dust chambers1 and thence to the flue system and stack4 ,modifications in the design of the blast-furnace superstructure have been1 however1 in course of progress at many works1 particularly in connection with the employment of automatic or mechanical charging appliances and the taking-off of the gases below the feed-floor level4 ,this is specially the case at plants operating the pyritic process and where the gases are to be utilised for acid manufacture1 as well as in connection with the treatment of smelter fume4 ,several furnaces are also at work using either metallic water-cooled or air-cooled tops1 from which the removal of accretions is stated to be very readily effected4 ,some of the most recent developments in the design of blast-furnace superstructure have been described by ,emmons in reviewing the experiments at the ,copperhill ,smelter1 ,tennessee4 ,the gases here are used for acid-making1 and are sent to ,glover towers under some pressure4 ,the furnace top consists of cast-iron corner-posts and dividers1 the walls and ends laid up with brickwork1 surmounted by a tubular top of the ,shelby type from which the gas off-takes lead4 ,the horizontally pivoted doors open inwards and fit tightly4 ,these arrangements are stated to be very satisfactory4 ,illustration3 ,fig4 #dc4--,showing ,upper ,jackets1 ,apron and ,mantel ,plates1 and ,superstructure of ,blast ,furnace1 ,anaconda4 ,illustration3 ,fig4 #dd4--;,charging ,blast ,furnaces at ,anaconda4 ,the charging platform1 suitably supported on vertical columns1 runs at the upper level1 being provided1 on either side of the furnace1 with tracks of rails for the charge cars4 ,the charging doors usually correspond in position to the panels of water-jackets1 and are situated along the whole length of each side furnace-wall1 the bottom of the charging opening being flush with the floor4 ,they are generally moved up and down in the grooved guides of the upright columns between them1 and are of sheet steel suitably strengthened1 from #f to #g feet wide and #d feet #f inches to about #e feet high1 supported by wire-rope and chains1 and operated by compressed air cylinders4 ,the ,air ,supply to the ,blast ,furnace4--,the quantity of air required by the blast furnace varies very widely with the class of work1 rapidity of output1 character of charge1 and general smelting conditions4 ,it may be stated roughly as being from #cjj to #ejj cubic feet of air per minute per square foot of hearth area1 at a pressure of about #dj to #ej ozs4 per square inch4 ,the rotary blower of the ,roots or ,connersville type is very well suited for the supply of these enormous quantities of air at moderate pressures1 but for blast at higher pressures the air leakage becomes excessive1 and piston-driven blowing engines become almost a necessity4 ,such improvements have1 however1 been made in rotary-blowing appliances within recent years that most blast-furnace plants are equipped with blowers of the rotary type1 which are found highly satisfactory4 ,the air is brought along blast mains of considerable size--about #cj inches diameter--to the furnace building1 thence to the bustle pipes of #bd inches diameter1 which surround the furnace1 from which branch off the pipe connections 7#e or #f inches diameter7 for the tuyeres4 ,the practice of equipping each furnace with its own blowing unit is fairly general1 making the necessary reserve connections in case of temporary breakdown2 many smelters1 however1 adopt the system of delivering the air from all the engines into one large common air main1 making the necessary connections from this to each separate furnace4 ,the importance of avoiding leakages is recognised1 and the requisite valves for regulating and controlling the air supply are arranged for4 ,from the bustle pipe the air passes down the pipe connections which are attached by flanged joints1 thence to the tuyere pipes1 which are of cast-iron1 the blast being regulated by valves4 ,the actual form of tuyere employed varies considerably1 each smelter usually having its own special devices for the convenience of repair1 renewal1 and fixing1 as well as for valve regulation and punching4 ,the tuyere is held against the face of the jackets by bolts1 leakages being prevented by asbestos packing4 ,illustration3 ,fig4 #de4--;,blast-,furnace ,shell1 with ,air ,connections 7,p4 ,m4 ,m4 ,co474 ,illustration3 ,fig4 #df4--;,details of ,tuyere1 ,cananea ,blast ,furnace4 ,the tuyeres are usually #d to #e inches in diameter1 and are generally placed about #ab inches apart4 ,air is supplied only through the side jackets1 and not at the ends of the furnace4 ,heating the ,air ,blast4--,the advisability of heating the air-supply for copper blast-furnace smelting has been the subject of very considerable discussion1 the question requiring consideration both with respect to its influence on the rationale of the smelting operation as well as from the economic standpoint4 ,the matter is dealt with more fully in connection with pyritic practice1 from which point of view ,peters has reviewed the subject exhaustively4 ,it may be here stated that there appears to be no advantage in preheating the air when the true pyritic process is operated1 and actual trial has resulted in the rejection of the method at the smelters practising this work4 ,where1 however1 coke fuel to any considerable extent is employed on the charge1 a supply of heated air through the tuyeres may result in an increased rapidity of smelting1 as well as in the production of hotter and more fluid slags4 ,especially in partial pyritic smelting and more particularly when working charges which contain but little sulphide and where the employment of much coke is not advantageous1 the use of preheated blast may be economically very useful4 ,in such cases1 the heat production in the furnace is not so fundamentally bound up with the thermo-chemical reactions of slag formation as it is in true pyritic smelting1 and therefore the enhanced intensity of combustion of coke-fuel at the tuyere-zone by the use of hot air may exert an important influence in improving the furnace operation and in decreasing the amount of coke-fuel required4 ,in many such instances indeed it has been chiefly the economic factor with reference to the cost of installing and operating suitable devices for warming the air-supply which has determined the question of adopting this system4 ,as is well known1 the use of a supply of heated air causes a largely increased calorific intensity from the combustion of coke1 resulting in higher temperature at the tuyere-zone1 under which circumstances the charge materials are smelted more rapidly1 and the resulting products are more fluid1 whilst slags of higher silica content 7sometimes economically advisable7 can be conveniently worked with4 ,the devices employed for the preheating of the blast vary considerably--cheapness1 capacity1 simplicity in design and operation being the main essentials4 ,the utilisation of the waste heat from the smelting furnaces or products would suggest itself as an economical method for accomplishing the warming of the blast1 but in practice several difficulties are encountered in efficiently making use of this heat4 ,heat is available from two sources1 either from the furnace gases or from the hot slag4 ,the very successful operation in cast-iron smelting1 of hot-blast stoves worked by the 8waste gases10 cannot1 however1 be applied to copper blast-furnace smelting1 since the gases in this case do not possess similar calorific value owing to the small proportions of carbon monoxide present4 ,further1 the temperature of these gases is not sufficiently high to allow of the effective application of the regenerative principle using brickwork chambers4 ,in consequence1 the use of metal pipe-stoves offers the only method of utilising the heating values of the furnace gases1 but their comparatively low temperature does not afford sufficient heat for the warming of the large quantities of air which are required at the tuyeres4 ,the much higher temperature of the reverberatory furnace gases offers1 however1 much greater scope for their utilisation in this respect1 if both classes of furnace happen to be in operation at the plant and if they are conveniently situated for the purpose4 ,at several smelters1 blast furnaces have been equipped with hot-blast 8tops0 for the purpose of preheating the air supply1 the air-heating pipes being exposed to the gases in the upper portions of the furnace4 ,the ,giroux blast-heating device has been installed on furnaces at smelters in ,mexico and ,arizona1 whilst at others in the same localities1 the ,mitchell system of baffle passages has been successfully used4 ,the ,kiddie system of running the blast pipes through the dust chambers has been tried at ,tyee1 ,b4,c4 ,the advantages of thus utilising the heat of waste gases have generally1 however1 been found to be more than balanced by the extra costs involved4 ,efforts have been made to use the heat contained in molten slag for warming the air1 but owing to the low conducting power of these materials1 and the difficulty of bringing extended surfaces in close contact1 the method has not proved itself very efficient4 ,blast is occasionally warmed by passing the air through tunnels in which bogies of molten slag are allowed to remain for some time4 ,when methods of utilising waste heat from the furnace products fail1 the fuel-heated iron pipe-stove is generally employed4 ,since the temperatures required are comparatively low1 and the margin of profit involved by the use of hot blast is usually small1 the use of the cheapest class of fuel available is imperative2 but many classes of fuel unsuitable for other purposes may find useful application for this work4 ,the stove is of the usual shape3 alternating up-down pipe cast-iron pipe form1 designed to give the maximum exposing surface1 suitably strengthened and protected from direct action of the fire4 ,much valuable information on the advantages1 disadvantages1 and appliances for blast heating was afforded by the smeltermen who contributed to the symposium on 8,pyrite ,smelting10 which ,rickard edited for the ,engineering and ,mining ,journal4 ,references4 ,mathewson1 ,e4 ,p41 8,the ,development of the ,modern ,blast ,furnace40 ,eng4 and ,min4 ,journ41 ,may #bg1 #aiaa1 p4 #ajeg4 ,wright1 ,lewis ,t41 8,metal ,losses in ,copper ,slags40 ,bulletin ,amer4 ,inst4 ,min4 ,eng41 #aiji1 ,sept41 ,no4 #cc1 p4 #hag4 ,shelby1 ,geo4 ,f41 8,cananea ,blast ,furnaces40 ,engineering and ,mining ,journal1 ,april #beth1 #aijh4 ,emmons1 ,n4 ,h41 8,copper ,blast-,furnace ,tops40 ,bulletin ,amer4 ,inst4 ,min4 ,eng41 ,feb41 #aiaa1 p4 #aai4 8,heating ,blast40 ,engineering and ,mining ,journal1 ,june #af and ,sept4 #ae and #bi1 #aijf4 8,pyrite ,smelting10 ,t4 ,a4 ,rickard4 ,also the ,authors already referred to1 ,austin 7p4 #hj71 ,gowland 7p4 #ag71 ,peters 7p4 #hj74 ,,lecture ,,vii4 ,,modern ,,blast-,,furnace ,,practice 7,continued74 ,charge ,calculations -- ,charging -- ,working -- ,disposal of ,products -- ,pyritic ,smelting -- ,sulphuric ,acid ,manufacture from ,smelter ,gases4 ,charge ,calculations4--,modern practice aims at the production of a matte of converter grade1 containing usually from #dj to #ej per cent4 of copper1 and preferably in a single smelting operation2 except in true pyritic work4#ab ,full analysis of the whole supply of material available at the smelter is essential1 as well as a report on the quantities of each separate constituent4 ,the first step in the charge-calculation is the computation of the total weights of copper1 iron1 and sulphur available for the smelting campaign2 from these quantities the losses of copper and sulphur to be allowed for during the operation itself1 as based on previous experience1 are deducted4 ,the balance indicates the quantities of these elements from which the matte and slag can be produced4 ,the copper is transformed into matte1 in which product it may be regarded as existing in the form of copper sulphide1 ,cu#b,s1 and the sulphur required for this combination with the copper is calculated from the relation-- ,cu#b,s ,cu#b 3 ,s 33 #b #fce 3 #cb 33 #abg 3 #cb 33 #d 3 #a approximately4 ,thus every unit of copper combines with one-quarter of its own weight of sulphur4 ,a matte of converter grade containing1 say1 #dd per cent4 of copper is constituted as follows3--,copper1 #dd per cent4 sulphur1 #aa per cent41 or copper sulphide1 #ee per cent41 the remaining portion of the matte being iron sulphide1 which amounts to #ajj #ee1 or #de per cent4 ,assuming as a first approximation that this iron sulphide has the formula ,fe,s1#ac the proportions of iron to sulphur in this material are ,fe 3 ,s 33 #ef 3 #cb 33 #g 3 #d hence #g_/aa of the remaining #de per cent4 of the matte is iron and #d_/aa is sulphur--that is1 the matte contains in addition1 iron #bh parts1 sulphur #ag parts4 ,hence the composition of the converter matte is approximately--,copper #dd parts1 iron #bh parts1 and sulphur #aa #ag #bh parts4 ,the amount of copper for the matte is fixed by the available ore supply2 the quantity of sulphur is controlled by the furnace operation and charges1 as judged from previous experience--the oxidation being so regulated that the proper grade of matte is produced4 ,the iron required for the matte is next considered4 ,every #dd parts of copper require #bh parts of iron for the production of a matte of the correct grade4 ,if the quantity of iron in the materials available at the stock-bins be not sufficient to furnish the amount required1 as just calculated1 ferruginous material must be added as flux1 if1 on the other hand1 there is a superabundance of iron available in the charges for this purpose1 the excess must be fluxed off4 ,in this manner the amounts of the constituents for the matte production are determined1 and the composition and making up of the slag-forming constituents are next considered4 ,in this connection the local conditions with respect to proximity and cost of suitable flux1 as well as experience with the previous working of the furnace and ore charges are important factors in determining the type and composition of the slag to be made1 whilst in true pyritic practice the special conditions of working fix certain limits to the composition of the slag1 as will be indicated later--the pyritic furnace 8tending to make its own slag40 ,in partial pyritic smelting1 the coke allowance and the furnace conditions allow of fairly wide latitude in making up the charges for the production of suitable slags with which the furnace can deal efficiently1 since the heat production is not dependent on the formation of any particular slag4 ,it is always possible to add extra coke for the purpose of melting the slag desired4 ,the scientific principle governing the calculations for slag composition is the proper proportioning of acid and basic constituents4 ,this is based upon the oxygen ratio--i4e41 the proportion of oxygen in the acid constituents compared with that in the bases4 ,with the doubtful exception of alumina in certain cases1 silica constitutes the entire acid portion of most copper-smelting slags4 ,the requirements for a satisfactory slag are that it shall be-- 7a7 ,fusible at the temperature of furnace working4 7b7 ,fluid and run easily4 7c7 ,of sufficiently low specific gravity as will allow of good settling and separation of the matte or metallic products4 ,it is well known that within certain broad limits of silica content1 slags will fulfil these conditions to a greater or less extent1 whilst the most suitable and economic slag under any particular circumstances is decided1 as stated above1 by the composition of the charge1 the quantity and character of the available fluxes1 and the previous experience with the furnace4 ,the limits of the silica content for suitable slags as just indicated are fixed by several well-known general properties of the silicates4 ,speaking broadly1 and from the point of view of the more or less ferruginous silicates constituting copper-smelting slags1 the more basic silicates--such as the subsilicate class 7oxygen in acid 3 oxygen in base #a 3 #a7--;are generally characterised by high formation-temperature1 and by being very fluid1 thin and fiery1 dense and corrosive4 ,on the other hand1 the more acid silicates1 such as those of the multi-silicate class 7oxygen in acid 3 oxygen in base #b 3 #a7 are characterised by lower formation-temperature and low density1 and by being thick and viscous4 ,as the silica content within this range of silicates increases1 the melting point is lowered and the specific gravity is reduced1 features which are very advantageous from the point of view of the production of clean slags4 ,their fluidity1 however1 decreases1 and a very high temperature is thus required in order to render them sufficiently limpid to run freely from the furnace4 ,on this account the highest proportions of silica usually considered feasible in a slag1 correspond to the bisilicates of the representative composition1 ,,mo4 ,si,o#b4 ,with high temperature conditions in the furnace and rapid working1 such slags can be dealt with successfully1 and if the charges are necessarily highly siliceous1 it may be advantageous from the economic point of view to work with this class of slag4 ,in proportion as the silica content gradually decreases and as they become more basic1 the silicates are more and more corrosive and fiery1 and especially in the case of the iron silicates1 they gradually attain such a high specific gravity that efficient settling of the matte is not possible4 ,in addition1 the more basic the silicate the greater is its dissolving power for sulphides1 hence high copper losses in the slags result from these combined causes4 ,such basic silicates possess1 however1 the advantage of marked liquidity1 and of flowing from the furnace in a thin limpid stream4 ,the high density and the solvent power of basic slags thus fix a limit to the composition which is considered economically suitable1 and the lowest proportions of silica usually worked with correspond to the mono-silicates represented by the formula #b,,mo4 ,si,o#b4 ,slags containing a greater proportion of base 7usually iron7 possess too high a density to permit of clean settling4 ,in practice1 therefore1 the majority of slags are mixed silicates of a composition ranging between the limpid but somewhat dense mono-silicate and the lighter but more viscous bisilicate1 corresponding to silica contents of from #cj to #dh per cent4 of silica1 and within the limits of #ce to #de per cent4 of silica most copper blast-furnace slags will be found4 ,the composition roughly corresponds in a large number of cases to that of the sesqui-silicates of the general formula #d,,mo4 #c,si,o#b 7oxygen in base 3 oxygen in acid 33 #d 3 #f 33 #a 3 #a74 ,as is well known1 mixed silicates--i4e41 silicates of two or more bases--are generally characterised by the properties of increased fusibility1 and often of increased fluidity1 and their employment is usual and generally advantageous in smelting practice4 ,the relative proportion between the various bases in such mixed silicates is largely a matter depending upon the prevailing conditions at the smelter4 ,in modern smelting1 particularly where partial pyritic work is conducted1 and where fairly siliceous charges are worked1 a slag running about #dj per cent4 ,si,o#b is aimed for1 iron and earth oxides constituting the remaining #fj per cent4 or so4 ,in cases where this quantity of iron is present in the charge1 the slag may be constituted chiefly of iron silicate1 but even in such instances the advantages of lime additions are marked4 ,when iron is not available in sufficient quantity1 the extra fuel costs and working difficulties of running with more siliceous slags would render their production undesirable1 and the purchase of limestone or similar earthy flux is particularly advantageous4 ,the purely iron silicates are usually dense1 and thus tend to hold up copper values both in mechanical suspension as well as in solution2 the addition of lime1 which has a marked effect in reducing the specific gravity1 permits of more basic slags being worked with1 where necessary1 without such heavy losses in the slag4 ,the presence of lime silicate with the iron silicates has a marked influence on the fluidity of the slags1 even when they are more highly siliceous1 whilst on account of the lower atomic weight of calcium1 lime will1 weight for weight1 flux off a greater quantity of silica than will ferrous oxide4 ,in forming a slag of similar oxygen ratio1 thus-- ,mono-silicate of lime1 #b;,ca,o 4 ,si,o#b1 ,lime 3 silica 33 #aab to #fj1 or #a part to #jed part4 ,mono-silicate of iron1 #b;,fe,o 4 ,si,o#b1 ,iron oxide 3 silica 33 #add to #fj1 or #a part to #jdb part2 hence for the production of a slag of the same oxygen ratio1 less weight of lime would be required to flux off the same weight of silica2 in other words1 the replacing values of the two oxides are as #aab to #add1 or #g to #i4 ,of the other bases which are occasionally present in slags1 the proportions of the oxides of magnesium and zinc are sometimes considerable1 the calculations being analogous to the previous cases4 ,the case of alumina is anomalous1 and its behaviour in slag production is not definitely understood4 ,many experienced workers hold the view that it tends to act either as acid or base1 according to the proportions of silica4 ,thus1 in a very siliceous slag1 alumina in moderate quantity behaves as a basic oxide1 forming aluminium silicates1 and in very basic or low silica slags the alumina appears either to neutralise some of the excess base1 acting as an acidic oxide1 or to dissolve as such in the slag1 whilst in intermediate cases it possibly behaves partly as an acid and partly as base4 ,this view has recently been questioned1 and it has been suggested by ,shelby that alumina always acts as an acid in the formation of slags4 ,the matter is thus one which requires further considerable investigation4 ,usually neither alumina nor zinc oxide behave very satisfactorily in the furnace when present in large quantities1 tending to thicken the slags and to promote viscosity4 ,anaconda ,practice in ,charge ,calculations4--,an example of some of the practical considerations which enter into the calculation and making up of charges is well illustrated in certain particulars of the practice as conducted at ,anaconda4 ,details of the materials charged over a period of one month are indicated in ,table ,x4 ,the important charge constituents available in large quantity include3-- ,cu4 ,si,o#b4 ,fe7,o74 ,s4 ,first-class smelting ore1 #hf #edj #acf #adj ,concentrates1 #aji #bfj #cbj #cbj ,briquettes1 #ej #ejj #acj #acj ,lime-rock 7flux71 44 44 44 44 ,old converter slags and residues1 44 44 44 44 ,,table ,x4--,,blast-,,furnace ,,charge ,,calculations--,,total ,,charge1 ,,all ,,furnaces4 ,tons of ,si,o#b4 ,fe,o4 ,ca,o4 ,charge4 ,tons4 ,tons4 ,tons4 ,first-class ore1 #bh1fdfebhjae1abeadij #d1bfh #jej #adc ,second-class ore1 #a1iacecej #a1jbcaegi #cjj #jfj #aa ,lining ore1 #ebhcga #dd #daf #b #jfg #a ,b4 and ,b4 slag1 #f1ffgceih #b1ciidgbg #c1aeb #aaa #gd ,b4 and ,m4 slag1 #dhadbib #bjfdbad #bjc #jab #a ,precipitates1 #ccc #hjj #bgabdj #db 44 44 ,precipitates from old works1 #da #bgj #aaedj #f 44 44 ,slimes from old works1 #aieffj #aafej #a #jhj 44 ,coarse concentrates1 #ad1jhcbebg #c1eehcbif #d1fdb #jde #fc ,calcine bearings1 #bcb #iej #bbegjj #acb #jhj #b ,briquettes1 #bg1efjdhggac1ddaaeaf #d1agg #jfe #agi ,reverberatory matte1 #adf #dcj #fcgej #ee #jhj #a ,reverberatory slag1 #fhgdcaj #bifcifj #bgb #djj #bg ,converter cold matte1 #eebacfj #gebiej #afc #dij #bg ,converter slag1 #i1iiicacj #c1abieeij #e1ehi #jgj #gj ,converter cleanings1 #g1hiacjec #b1dcgcfee #b1iag #jgi #fd ,lime-rock1 #fa1gid #fij #d1bfd #jej #cjidhhjcj1aee ,coke1 #ah1gffbce tons1 at #ad4ba per cent4 ash1 #b1ffgdebh #a1bjhabba #cbf #fca #afh ,total charge1 #afc1hecbhhedg1bgbafbabf1eefahiacj1ihf ,total production1 #ah1ddg #fch #a1aiabicf #e1dhf #aeg #bic ,to slag1 44 44 #df1jha 44 #ba1jga 44 #cj1fic ,tons of ,sulphur4 ,copper4 ,charge4 ,tons4 ,pounds4 ,first-class ore1 #bh1fdfaeej #d1ddj #ffda #c1hjd1eee ,second-class ore1 #a1iacadfj #bgi #edgf #bji1ddg ,lining ore1 #eb #ade #a #chcd #c1ihh ,b4 and ,b4 slag1 #f1ffg 44 44 #jgig #ajf1cbe ,b4 and ,m4 slag1 #dha 44 44 #aiai #ah1dej ,precipitates1 #ccc 44 44 #ehhec #cib1ceb ,precipitates from old works1 #da 44 44 #fhcdd #ef1fjg ,slimes from old works1 #ai #gej #a #dbjc #a1fcg ,coarse concentrates1 #ad1jhccbaj #d1ebaajghb #c1jcf1hjb ,calcine bearings1 #bcb #dej #aj #icba #dc1bcj ,briquettes1 #bg1efjaecb #d1bbc #dibh #b1gaf1bii ,reverberatory matte1 #adfbccj #cdcegeb #ajd1fea ,reverberatory slag1 #fhg #aaj #h #aeff #ba1eja ,converter cold matte1 #eebahbj #ajjdbfge #dgj1hci ,converter slag1 #i1iii #aaj #aaj #cjah #fjc1dbi ,converter cleanings1 #g1hia #ffj #ebhafhdj #b1fhh1jbd ,lime-rock1 #fa1gid 44 44 44 44 ,coke1 #ah1gffbce tons1 at #ad4ba per cent4 ash1 #b1ffg 44 44 44 44 ,total charge1 #afc1hec #hgjad1bee #dcegad1bgh1acf ,total production1 #ah1ddgbaac #c1hihcidhcad1efg1cgf ,to slag1 44 44 44 44 44 ,si,o#b in slag1 #df1jha #aaj1haj tons slag ,fe,o in slag1 #ba1jga #aaj1haj ,ca,o in slag1 #cj1fic #aaj1haj ,total1 #ig1hde tons1 at #hhcj per cent4 #aaj1haj tons slag4 ,coke consumption1 #ajfc per cent4 wet weight #ajif per cent4 dry weight4 ,analysis4 ,si,o#b in slag1 ,calc4 #daei ,actual #dacj ,fe,o in slag1 #aija #aijj ,ca,o in slag1 #bggj #bhjj #hhcj #hhcj ,the other constituents used in the charge comprise varying quantities of materials which accumulate round the works1 and which1 being rich in copper values1 it becomes useful and essential to clean up4 ,for the calculating of the furnace charges1 the amounts of cupriferous material available at the stock-bins are reported to the blast-furnace department4 ,the quantities decided upon are divided among the number of charges which are considered likely to be worked off during the day1 this number averaging about #a1ajj4 ,the result of this calculation indicates the amount of each kind of material to be weighed for the separate charges2 the analysis of each constituent being naturally known4 ,the materials available for smelting are highly siliceous in character1 the first-class smelting ore1 of which large quantities are treated1 giving a strongly acid composition to the charge2 copper-bearing basic materials suitable for fluxing are not available in large quantity1 and this necessitates the purchase of barren lime-rock1 this item being the largest of the blast-furnace charge4 ,in making up the charge sheet1 as large a quantity of concentrate as possible is included1 since this constituent is not only high in copper values1 but owing to a high iron and sulphur proportion1 it increases the fuel value of the charge1 the influence on the coke consumption being very marked4 ,the concentrate further forms a base for the matte1 and introduces iron1 of which there is a shortage1 into the slag1 thus reducing its too-siliceous character and lessening the quantity of lime which it would otherwise be necessary to procure for the purpose4 ,the briquettes are next worked in to as great an extent at possible1 since by this means the large stocks of settling-pond slime and of screened fines are reduced and their #e per cent4 of copper is extracted4 ,the whole stock of old slags and residues is used up on the charge1 these materials introducing considerable amounts of copper1 whilst being irony1 they further help to reduce the acidity of the slag1 thus saving the employment of the lime-rock otherwise required for fluxing4 ,the total quantity of copper1 iron1 and sulphur available being then calculated1 and the allowances for sulphur elimination and for the copper loss on smelting 7#b to #g per cent471 as based upon previous experience1 being deducted1 the amount of iron required to constitute the #de per cent4 copper matte is estimated4 ,from this figure the ,fe,o remaining for slag production is determined4 ,the silica introduced by the above materials is also known1 and the amount of lime-rock required to produce an easily running slag is next calculated4 ,the slag which is found by experience to give the most satisfactory running has a composition of about-- ,si,o#b1 #da per cent4 ,fe,o1 #ai ,ca,o1 #bi ,variations from this composition1 especially as regards higher silica contents1 immediately introduce difficulties1 increasing the expense of furnace running1 by requiring more fuel and care in working1 reducing tonnage1 and producing a slag which runs far less freely4 ,so that although the large quantity of siliceous material at hand might tempt the management to work with a more siliceous slag1 and so save the procuring of such large amounts of barren lime-rock1 the cost of this material is much more than compensated for by the advantages which result from the working with a slag which contains only about #dj per cent4 of silica4 ,the quantities of the charge constituents thus calculated1 divided by the likely number of charges to be worked1 are entered up on the charge sheet1 which is handed over to the charge foreman4 ,illustration3 ,fig4 #dg4--,v-,shaped ,charging ,car1 indicating ,mechanism for ,release and ,tilting4 ,the ,charging of the ,blast ,furnace4--,the method of 8hand charging10 as employed in the older processes of working1 when using small furnaces of small output1 possessed several theoretical advantages1 but it is essential in modern practice1 where at least #cjj tons of charge1 and often much larger quantities1 are fed into the blast furnace daily1 to employ mechanical means for charging4 ,at many smelters1 however1 the coke is added separately1 from barrows4 ,care in the charging is now recognised as being of special importance for successful blast-furnace operation1 especially for the purpose of procuring the correct distribution of coarse and fine material4 ,the principle of keeping the sides more open by distributing the coarser materials against the jackets and keeping the fine parts nearer to the centre is often favoured1 since this device reduces the tendency to crusting by the finer sulphide particles against the walls4 ,it is partly with this object in view that the mantel and apron plates are arranged in the hopper form1 whilst at the same time the distance between the top of the charge and the feed-floor level is maintained at such a height that this desired distribution of the fresh charges is obtained4 ,the practice still commonly employed is to feed the materials from side-dumping cars 7of very varied design7 brought along in a train drawn by locomotives and travelling along tracks running at each side of the furnace4 ,a form of car frequently used has a ,v-section1 and it is secured in a vertical position whilst in transit by some form of catch-pin device1 which is readily released when it is required to tilt the car for charging4 ,another form1 employed at ,anaconda1 has a shape3 flat base with sides sloping inwards shaped section1 the sides of which are pivoted and admit of being very readily secured or unfastened as desired4 ,the car bottom itself is tilted by connecting it with a compressed air lift by means of a hook situated at the side of the car remote from the furnace4 ,the material is thus discharged along the inclined chute so produced4 ,an interesting method is employed at the ,granby ,smelter1 where the ,hodge car and the end-feeding method are in use4 ,the cars1 which have a double-hopper discharge1 are divided into four compartments by vertical plates4 ,these cars enter at the ends of the furnace through suitable openings at the level of the feed-floor1 and run by small wheels on tracks which are built inside the furnace along the side of each vertical wall4 ,in this manner a straight vertical fall for the charge is arranged1 and this affords the best control of proper distribution4 ,the furnace holds three cars at a time1 and there are patent openers and closers for manipulating the end doors of the furnace1 as well as for releasing the hopper-bottoms of the cars4 ,a particularly ingenious and successful device is in use at the ,ducktown ,smelter of the ,d4,s4,c4,i4 ,co41#ad ,tennessee1 where the pyritic process is operated4 ,careful charging is here held to be one of the great essentials for successful working of the process1 especially in the narrow furnaces in use1 where the dangers of crusting are greatly increased4 ,the principle of working is1 that by dropping the charges vertically downwards1 having previously arranged the materials in the desired order across the furnace1 they will fall into the position1 and be distributed just as desired4 ,the ,freeland charger is a kind of conveyor belt made of overlapping steel plates1 which is exactly the length and width of the furnace1 so that when the machine is brought over it1 the furnace opening is entirely covered4 ,the conveyor is carried on a frame mounted on wheels1 and this is moved forward and backward by a motor in the front1 near which is seated the chargeman who is also the motorman4 ,an independent switch and gearing causes the belt to move round and thus deposit its charge over the end4 ,in front of the frame is a strong catch1 fitting into a recess on the cover of the furnace1 which is water-cooled and mounted on wheels1 so that as the conveyor is brought into position the cover is moved back4 ,all these run along a track which extends below the stock feed bins in the same straight line4 ,the furnace gases are drawn off below the feed-floor4 ,illustration3 ,fig4 #dh4--;,end ,view of ,blast ,furnace1 showing ,tilting of ,charge ,car1 ,anaconda4 ,illustration3 ,fig4 #di4--;,hodge's ,charging ,car4 ,the method of working is to bring the charger under the bins and to drop the various materials for the charge--weighing #b tons--on to the belt4 ,by deflectors on the ore chutes1 the charge can be directed to any desired position across the belt1 and material is thus deposited near the outer or inner side as desired--in falling into the furnace it is found to take the same position that it had on the plates4 ,the charger moves forward and reaches the furnace top1 the catch is fastened1 and as the charger now advances the cover is pushed back1 the conveyor thus taking its place until in its turn it covers the top of the furnace4 ,the motion is now reversed1 the conveyor gradually recedes1 bringing the cover along with it2 meantime the chargeman has set the belt-conveyor gearing working independently1 and the belt thus travelling round and over the end pulleys1 discharges its burden into the furnace4 ,the disposition of the charge along the length of the furnace can be altered at will by increasing or reducing the speed of the frame4 ,when the conveyor has at last traversed the furnace1 the cover is in its place--the charger is now disconnected1 and goes back for a fresh load4 ,the furnaces are charged eight times per hour with #b tons of material4 ,the operations are fascinating to observe1 and the control over the disposal of the charge is quite complete1 whilst the conditions for the operator are not exceptionally arduous4 ,many other suitable devices are in use at different works4 ,at the ,cananea smelter is operated an ore-bedding system1 the store-bins feeding the charge down hoppers through which it falls directly into the furnace4 ,a similar feeding system is in use at ,garfield1 ,utah4 ,the lay-out of the plant to allow of the most efficient charging is so arranged as to locate the stock-bins at a high level1 so that ore is fed directly from the discharge chutes into the cars of the charge trains which run on tracks underneath1 and these tracks are situated at such a level that the trains are readily and conveniently hauled to the charging platforms of the blast furnaces4 ,illustration3 ,fig4 #ej4--;,freeland ,charging ,machine 7,d4 ,s4 ,c4 ,i4 ,co474 ,illustration3 ,fig4 #ea4--;,freeland ,charger--,details4 ,the charge foreman receives from the blast-furnace department his charge sheets which inform him of the amounts of the various materials to be loaded on to each car--calculated in the manner already indicated4 ,proceeding to the stock-bins1 the gates and chutes of which are automatically controlled1 he sets the scale of the weigh-bridge which is situated under each bin to the desired weight4 ,at the same time an electric-light indicator is switched on in front of the particular bins from which material is to be withdrawn1 thus assisting in spotting the cars and checking the weighing-out4 ,the charge train is brought along the tracks running underneath the bins1 and into each car is dumped the correct amount of charge1 usually to within #ej lbs41 with rapidity and ease4 ,the train then passes to the furnace building1 where the charges are dumped or otherwise emptied into the furnace4 ,the ,coke ,allowance4--,as has been already indicated1 the coke allowance depends largely upon the nature of the charges and the individual experience at the smelter4 ,the main principle involved is to reduce the coke consumption as much as possible by applying the pyritic principle to the fullest possible extent1 working as much sulphide material into the charge as is economically practicable4 ,in partial pyritic smelting1 where the coke may constitute from #e to #aj or #ab per cent4 of the total charge1 it is usual not to feed it in with the rest of the materials from the cars1 but to charge it into the furnace separately4 ,the charge foreman puts it in just when and how he considers it necessary1 and he is encouraged to use as little as possible1 consistent with proper running of the products at the slag spout4 ,in pyritic smelting proper1 the small amount of coke is fed on to the top of the charge-material in the charge-cars4 ,working of the ,blast ,furnace4--,the top of the charge1 which is usually some #c to #e feet below the level of the feed-floor1 appears fairly uneven1 there being a tendency for it to sink along the middle4 ,it is moderately hot1 showing practically a black heat except where red-hot patches near the side appear in positions corresponding to where the tuyeres are situated below4 ,there is not very much fume at the feed-floor level if the chimney draft be good1 nor excessive agitation at the top1 unless much fine material is being worked4 ,sulphide fines tend to the formation of accretions near the top of the charge and occasionally lower down1 also to a considerable extent against the walls of the brick superstructure--this is said to be lessened considerably by the use of water-jacketing at these parts1 which also greatly assists the barring down of the masses4 ,a considerable amount of barring is sometimes necessary when much fine concentrate is worked1 otherwise a well-managed furnace runs smoothly and satisfactorily under favourable conditions4 ,trouble may arise occasionally by leakages occurring in the jackets or spouts1 but by the modern methods of sectional construction and by the devices for time-saving in making the necessary connections1 working is usually not seriously interfered with for a very long period4 ,even for the removal or replacement of a slag spout1 the slag-hole is plugged1 and the repair is completed within an hour and a-half1 by which time slag is again running freely over the replaced slag spout4 ,the tuyeres are punched regularly two or three times per shift1 and a steady stream of material issues from the slag notch and over the spout to the settlers4 ,disposal of the ,furnace ,products4--,under ordinary circumstances1 the products resulting from the blast-furnace operations include-- 7a7 ,the liquid matte and slag mixture which is given opportunities to settle and separate into valuable matte and waste clean slag4 7b7 ,the 8gaseous0 products carrying considerable quantities of fume and dust which are settled and separated in dust catchers and flues1 where the solid matter is collected4 ,illustration3 ,fig4 #eb4--,slag ,spout1 showing ,method of ,trapping ,blast1 also ,replaceable ,nose-piece of ,spout 7,a74 ,the ,matte and ,slag4--,in modern practice1 as already indicated1 the fluid products of the blast furnace are run out of the furnace as rapidly as possible1 and flow continuously1 as they are formed1 through a trapped slag notch4 ,so important has this principle of rapid removal of the fluid products become1 that the hearth or crucible portion is being made smaller and smaller4 ,the slag notch1 is1 in addition1 placed so low that only so much molten material remains in the furnace bottom as is necessary for the regulation of the temperature for maintaining perfect fluidity of the materials during their discharge1 and for avoiding crust formation on the hearth4 ,the depth of material remaining in the bottom--that is1 the distance from the hearth bottom to the slag notch--is from about #h to #ab inches1 depending on the conditions just indicated4 ,the discharge of the furnace products takes place through the trapped slag notch of the furnace1 an opening constructed in the tapping-breast or tap-jacket1 which is usually a small special jacket-portion constructed and kept in position separately on account of the great local wear at this point 7see ,fig4 #ci74 ,the trapping device is an important and essential feature in connection with the modern practice of rapid and continuous running1 the principle being to arrange a sufficient height of molten material at the outer side of the slag opening to overcome the inside blast pressure1 and thus prevent the escape of blast with its attendant inconveniences and danger4 ,the flow of liquid material can thus proceed quietly and uninterruptedly4 ,the blast is trapped by the construction of a dam in the form of a slag spout around the slag opening1 of such a shape and secured to the tap-jacket in such a manner and position1 that the molten material before overflowing at the end1 fills the spout and thus covers the discharge outlet of the furnace1 trapping the blast so that as fast as the molten products form1 a constant stream overflows into the settlers 7see ,fig4 #eb74 ,the slag spouts are often of sheet steel1 sometimes of copper or of bronze1 and are from #c feet #f inches to #e feet in length1 being separately water-cooled units4 ,the discharge at the end is from #ab to #ah inches higher than the centre of the slag notch in the tap-jacket through which the molten material issues from the furnace4 ,the spout is secured to the tap-jacket1 being arranged so as to admit of ready replacement where necessary4 ,usually it is bolted to the jacket and is securely wedged up against it1 being supported at the discharge end by the wall of the settler1 and the joints are made perfectly tight by very careful asbestos packing and claying4 ,the spout lasts for several months1 the greatest wear being at the end over which the molten stream issues1 but the life has been considerably lengthened1 with greatly increased convenience of furnace working1 by providing the spouts with separate easily replaceable water-cooled nose-pieces of cast-iron which are bolted to the ends1 thus taking up most of the wear and tear1 and allowing of a very ready removal and replacement without disturbing the slag-spout connections to the furnace itself4 ,these are indicated in ,figures #eb 7,a7 and #ei4 ,the slag spout is protected along its entire length by a hood of clay1 by which means the stream of matte and slag running down it is maintained hot and fluid4 ,illustration3 ,fig4 #ec4--;,details of ,slag ,spout1 ,cananea4 ,illustration3 ,fig4 #ed4--,slag ,spout1 showing ,method of ,support4 ,the position of the outlets from the furnace1 connecting to the settlers1 is largely affected by the available floor space and the general lay-out and arrangements of the plant4 ,under suitable conditions1 and especially with long furnaces1 the arrangement of the settler in front of the furnace works very advantageously1 leaving the alignment of the blast furnaces free1 and allowing plenty room for working around the settlers4 ,the settlers are then arranged in the middle line of the crucible portion of the furnace1 so that working is conducted evenly from both ends of the furnace towards the discharge in the centre1 and the smelting is thus regular and allows of good control4 ,at many smelters the discharge of products takes place from spouts at the ends of the furnaces1 the settlers thus being in alignment with them4 ,this plan1 under suitable conditions1 has several advantages1 permitting of ready access to the sides of the furnace1 even working of the furnace by discharge at both ends1 and ready co-operation between adjoining furnaces and settlers4 ,settlers4--,the modern type of settler is often circular in section1 about #af to #ah feet in diameter and #e feet in height1 storing about #dj tons of matte4 ,other forms1 rectangular or oval1 are1 however1 also employed4 ,the outer shell is of -inch steel plate bound together by band-bolts1 the lining is often #i to #ae inches in thickness1 with an inside layer of looser stuff4 ,the lining material employed varies greatly1 according to the grade of matte1 character of slag1 and working conditions4 ,the wearing out of the lining depends very largely on the class of material passing through the settler1 the most rapid wear being occasioned by the fiery and corrosive low-grade mattes and basic slags1 whilst high-grade mattes and more siliceous slags give little trouble in this connection4 ,the more corrosive the products1 the more refractory and hard-wearing must be the lining1 and consequently the materials employed for the purpose range from chromite1 silica brick and firebrick down to loam1 according to the requirements2 the chief duty is that of being non-corrodible and of protecting the outer shell4 ,it is not an uncommon practice to thicken the walls close to the tap-holes1 where they are subjected to most wear1 and often chromite is used at these points owing to its power of withstanding the forces of erosion4 ,on the other hand1 at the ,copperhill ,smelter of the ,tennessee ,copper ,company the settlers have been found to give as satisfactory service on fairly low-tenor matte1 when lined throughout with good firebrick as with the more expensive materials formerly used1 whilst still more recently1 siliceous copper ores have been successfully employed as lining material instead of bricks4 ,illustration3 ,fig4 #ee4--;,general ,view of ,settler 7,t4 ,e4 ,co474 ,illustration3 ,fig4 #ef4--,method of ,lining ,settler1 ,cananea4 ,illustration3 ,fig4 #eg4--;,arrangement for ,matte and ,slag ,discharge from ,settlers 7,t4 ,c4 ,c47 ,there is usually a spray of water from a circular pipe which surrounds the settler near the top--this playing against the steel sides keeps the outside cool and protects the lining4 ,the settler is roofed over with slag1 except at the back where the stream of matte and slag enters1 and also at those points where the slag overflows4 ,the slag escapes over short launders attached to the top of the steel casing4 ,the position of these discharges depends largely on the arrangement of tracks1 size of furnace1 temperature of working1 and quality of products4 ,under modern conditions of high temperature and rapid working1 they are situated as far away from the entrance as possible1 thus giving fuller opportunities for very quiet settling in a large pool and affording gentle overflow of slag with little abrasive action on the linings4 ,these outlets may be situated opposite to the entrance or at the sides4 ,the discharge spouts for slag may be one or two in number1 usually of cast-iron coated with thin clay1 and often roughly hooded over with clay4 ,they have replaceable cast-iron nose-pieces to facilitate repair after wearing down4 ,the continual gentle stream of slag runs along launders1 where it is either discharged into slag bogies and dumped1 or much better1 is met by a strong stream of water which immediately granulates it1 and washes it along flumes to the dumps4 ,illustration3 ,fig4 #eh4--,tap-hole ,casting and ,detail for ,settlers4 ,the matte tap-holes are generally two in number1 situated close to the bottom of the settler1 and usually at an angle of #abj from each other and from the entrance spout4 ,the hole through the brick wall for tapping is about #a inches in diameter1 and the matte is discharged through a tapping piece of cast-iron1 #f inches in diameter and #c inches thick1 perforated by a #a-;inch hole4 ,this iron disc has1 cast around it1 a copper tapping-plate about #a foot in width and #b feet high1 which is recessed into the steel sheet of the settler4 ,in the iron tapping-piece is a conical recess1 into which the conical clay plug is rammed when closing the tapping-hole4 ,these iron tapping-pieces withstand the action of converter grade matte fairly well1 and are conveniently replaced when necessary--about once a month4 ,they are illustrated in ,fig4 #eh4 ,the tapping-plate is fixed into position in a special section of the shell1 known as the launder casting1 to which the matte launder is secured1 whilst a newer form of settler has the tap sections also removable1 so that these can be taken out and the brick renewed during the campaign of a furnace1 being as readily removable as a furnace jacket4 ,the matte launder is of cast-iron or of steel1 thickly coated with clay or suitable material 7slime-pond product1 etc47 to protect it from corrosion4 ,in modern work the steel tapping bar is always rammed through the conical plug and tapping-hole until it just reaches the matte1 so that its withdrawal by ring and wedge is readily performed when the matte is to be tapped whilst by this means the tap-hole is securely closed4 ,the workers are protected from shots of matte1 etc41 during tapping or closing1 by means of a slotted sheet-iron hood which can be swung back when not required1 a convenient and useful as well as necessary precautionary device4 ,matte is tapped from the settlers into ladles as required by the converters2 such ladles are constructed of thick steel plate1 washed with clay1 and often lined with a hull of chilled material4 ,it is sampled at the runner with each tapping4 ,the tap-hole is closed by a clay plug on the end of a dolly which is rammed home1 and a warm pointed steel bar is then driven through until it reaches the matte1 being knocked in occasionally as the end is very slowly eaten away4 ,several of the features named in the previous sections are well indicated in the photograph 7,fig4 #ei7 of the tapping platform at the ,anaconda ,smelter4 ,the 8,gaseous0 ,products of the ,furnace4--,great variation is to be found in the arrangement at different works for the disposal of the gaseous products of the furnace4 ,reference will be made later to the methods employed in connection with pyritic work1 and where the gases are to be utilised for the production of sulphuric acid4 ,formerly the general method1 even at the large modern plants1 was to lead the gases from the top of the superstructure to the off-takes and large dust-catcher flues1 thence to the stack4 ,illustration3 ,fig4 #ei4--;,anaconda ,blast ,furnace 7#ea feet long71 showing ,settlers4 ,with the introduction of automatic and mechanical charging methods1 now being inaugurated to a considerable extent in place of dumping from cars alongside the furnace1 the method of withdrawing the gaseous products just below the level of the feed-floor is being adopted4 ,illustration3 ,fig4 #fj4--;,hoppers of ,flue-dust ,chambers and ,tracks for ,cars underneath4 ,the off-take flues of the modern furnace are of steel1 #d to #f feet in diameter--lined or unlined according to circumstances--and leading to very large dust chambers of varying design1 sometimes rectangular1 often of large circular section1 or of balloon-shaped section1 etc4 ,in all cases these flues are provided with hopper discharge openings at suitable intervals1 under which cars run on tracks1 for the collection and conveying of the dust4 ,arrangements for the further settling and collection of the flue-dust are essential in connection with modern blast-furnace plants1 where blast pressures of from #dj to #ej ozs4 per inch are employed and where it is often found economical to work with as much fine material as possible1 either as such or in an agglomerated form2 where too1 the dropping of charges from some height and the agitation caused by the blast are practically unavoidable4 ,rarely less than #b per cent4 of flue-dust is made in any modern blast furnace1 whilst #e per cent4 is by no means uncommon1 and even larger quantities are often produced4 ,such dust is1 moreover1 often somewhat higher in copper contents than the original charge1 owing to the brittleness of copper sulphide minerals1 which1 being more readily broken up1 are carried over in the form of fine particles4 ,hence the economic aspect of the recovery of values1 in addition to legislative requirements1 call for efficient collection of these products4 ,the gaseous products of the furnace carry solid matter in two forms4 ,as a rule1 under the usual conditions of copper-smelting charges1 the larger portion of the solid matter thus carried is in the form of very fine particles of charge material itself1 mechanically suspended and carried over in the current of the escaping gases4 ,this is the flue-dust4 ,in addition1 values in the form of volatilised metallic products are also conveyed by the gases1 particularly when lead1 zinc1 arsenic1 etc41 are present in the furnace charge1 and these are carried forward in the form of fume4 ,they tend to solidify as the temperature of the gases becomes lower1 although their settling is very greatly impeded owing to the exceeding minuteness of their particles and also to their dilution2 the problem of separating and collecting them is in consequence attended with great difficulty4 ,chambers of enormous capacity are required in order to give the fine solid particles an opportunity of settling by decreasing the velocity of the gases and by cooling them down1 whilst for the settling of fume1 capacious flues in which are suspended wires or similar devices for assisting the process must be adopted4 ,where large quantities of lead1 etc41 are present some bag-house system of fume filtration is necessary1 especially if silver be present1 since this metal tends to be carried over in the leady fume4 ,at the majority of copper smelters such extreme refinements are rarely necessary1 although modern legislative requirements make severe demands on the managements for the freedom of the gases from injurious constituents4 ,dry settling methods and filtration are in general use where such separation is required and the use of high-tension electricity has been successfully tried at ,californian smelters4 ,wet methods have so far not proved economically successful4 ,the flue-dust from the flues is dealt with in a number of ways1 according to the conditions at the smelter4 ,it may be smelted with the 8roaster-calcines charges0 in the reverberatory furnaces1 although excessive quantities have proved difficult to deal with in certain instances1 it may be included in the charges for sintering or briquetting processes1 and it has been very successfully incorporated with the matte in beds when it has been necessary to cast low-grade matte into cakes previous to re-concentration in the blast furnace1 at a smelter employing the pyritic process4 ,still more recently1 the ,east ,butte ,copper ,mining ,company has installed and successfully operated a sintering plant on the ,dwight-,lloyd principle for the treatment of the flue-dust preparatory to blast-furnace smelting4 ,the capacity of the plant is #ajj tons per day4 ,the material is rendered more or less cohesive by the effects of heat alone1 but the operation is not yet perfect4 7,see ,mining ,journal1 ,jan4 #fth1 #aiab1 p4 #ba47 ,the freed gases finally pass along series of long and capacious brick main-flues connecting with all the branch flues1 furnished with discharge hoppers at intervals1 gradually rising and discharging into a wide stack of such a height that damage to vegetation in the district is entirely prevented4 ,pyritic ,smelting4--,modern blast-furnace practice1 as has been stated1 is conducted according to two main systems of working3-- 7a7 ,that in which the heat required in the smelting zone is provided by the oxidation of the sulphide materials of the charge--,pyritic ,smelting4 7b7 ,that in which coke or other carbonaceous fuel is necessary for supplying some of the heat required in the smelting zone of the furnace1 even when the pyritic effect of the charge is utilised to the fullest extent--,partial ,pyritic ,smelting4 ,the term ,pyritic ,smelting 7or pyrite smelting7 is thus applied to that class of practice in which the whole of the heat required in the smelting zone is obtained by the combustion of the ore or matte charge itself2 it implies the application of the pyritic principle to the extreme limit1 the use of carbonaceous fuel being reduced to a minimum4 ,ideal working is to feed unroasted ore or matte1 together with the requisite fluxes1 into the blast furnace1 and by the action of an adequate air blast1 to burn out part of the sulphur and iron1 the former escaping with the furnace gases1 the latter being slagged off1 whilst the copper in the charge is concentrated in the matte product of the operation4 ,this type of smelting is conducted at a number of large modern works1 and though up to the present time the use of coke on the charge has not been entirely eliminated1 research and practical experience have demonstrated that the small quantity which is employed is not utilised as fuel by combustion in the air blast at the tuyeres1 but that it is1 in fact1 oxidised in another manner at some considerable height in the furnace4 ,history4--,the idea originated with ,john ,holway1 of ,london1 who sought to extend to the smelting of copper the principles so brilliantly applied by ,bessemer to steel manufacture1 and who1 in a work which was published in #ahgi1 suggested and demonstrated the process of utilising the heat of oxidation of the iron and sulphur constituents of copper-bearing materials for the smelting and extraction of the copper4 ,that work is to-day recognised as one of the most masterly expositions of the principles underlying pyritic smelting and converting1 and many of the most important and recent developments in these branches of work are proceeding on lines forecasted by him4 ,holway's experiments1 conducted on a considerable scale1 proved the feasibility of the principles underlying the process1 which was to prepare metallic copper from sulphide ores in one combined series of operations in a single furnace unit4 ,owing1 however1 to mechanical troubles and difficulties of operation1 as well as to the ultimate withdrawal of financial support1 he was unable to carry the process to a commercial success1 and the single-stage process is at present regarded as being beset by almost insuperable difficulties1 although the latest phases in modern practice are tending towards a realisation of ,holway's scheme of working4 ,his paper and published results deserve the closest study4 ,inspired by the pamphlet1 an ,english ,company in #ahhg-h attempted the practice at a smelter at ,toston1 ,montana1 and showed the possibilities of the method1 although the plant available did not lend itself to completely successful operation4 ,l4 ,s4 ,austin1 who took a leading part in this work1 patented the process in the ,united ,states1 and developed the practice1 and in #ahia ,dr4 ,peters conducted a very full enquiry into the conditions of working1 which placed the system on a definite practical basis4 ,from that time the method has developed coincidently with the more empirical practice at many works of replacing coke fuel by sulphides to as great an extent as possible4 ,t4 ,a4 ,rickard focussed scientific and practical opinion on the subject in the symposium on 8,pyrite ,smelting10 which he called forth and edited1 and many celebrated smeltermen have contributed to the progress of pyritic smelting practice4 ,at the ,copperhill ,smelter of the ,tennessee ,copper ,company and at the ,ducktown ,sulphur1 ,copper and ,iron ,co4's ,smelter at ,isabella1 ,tennessee1 remarkably good pioneer work was done by ,parke ,channing1 ,freeland1 and others in developing the process4 ,enormous service has been rendered within recent years by the masterly researches and brilliant exposition of ,robert ,sticht1 in which latter work ,peters has worthily seconded him4 ,pyritic smelting is at the present time being very successfully practised at ,mt4 ,lyell1 ,tasmania2 at ,tennessee2 ,tilt ,cove1 ,newfoundland2 and other districts1 whilst the smoke problem alone has prevented for a time a number of other smelters from successfully operating the process4 ,the ,mechanism of the ,process4--,the mechanism of the changes involved in the pyritic process is now fairly well understood in general outline4 ,one of the most important steps in elucidating the matter was made by ,sticht's discovery that the oxidation area of the furnace in pyritic smelting was confined to a narrow zone situated just a little higher than the tuyere level2 by actual experiment it was found that scarcely any free oxygen existed above this narrow tuyere zone4#ae ,it thus became evident that the first series of changes near the top of the charge were those mainly caused by the effects of heat alone1 and that only by a second series of changes lower down at the tuyere zone were the reactions of rapid and intense combustion and oxidation of the sulphides being effected4 ,finally1 at the bottom of the furnace1 the molten matte and slag collected and ran out4 ,thus the furnace operations proceed in two main stages2 preparation 7liquation of the sulphides from the charge7 in the upper portion1 and oxidation and fluxing 7bessemerising of the liquated sulphides7 in the oxidising tuyere zone or focus4 ,the usual and typical ore charged into the furnace in pyritic smelting is impure chalcopyrite 7essentially a copper-bearing pyrites1 ,fe,s#b74 ,when heated in an atmosphere free from oxygen1 this pyrites loses some of its sulphur and approaches pyrrhotite in composition4 ,on further heating in a neutral atmosphere more sulphur is evolved and the material approaches ,fe,s in composition1 whilst at very high temperatures and under favourable circumstances1 a still further quantity of sulphur is liberated1 resulting in the production of the well-known fusible iron sulphide1 which is the eutectic of the iron3 iron-sulphide series of alloys1 melting at #igj ,c41 and containing about #he per cent4 of ,fe,s4 ,thus in the pyritic furnace1 free sulphur is liberated as such at the upper levels1 and passes up the furnace unchanged until it meets free air above the surface of the charge1 when it there burns to ,,so#b4 ,the residual fusible sulphide melts1 trickles down1 and becomes the true pyritic fuel of the furnace4 ,the copper sulphide constituents of the charge are practically unaffected in composition by heat alone1 and they pass down the furnace with the rest of the charge unchanged until the hotter zones of the furnace are reached1 when these sulphides also liquate out1 become dissolved in the melting iron sulphides1 and are thus carried down to the oxidising zone4 ,until the sulphides meet free oxygen1 no further reactions proceed1 since they are without action on silica at even the highest furnace temperatures4 ,when1 however1 they reach the blast of air which enters the furnace at the tuyeres1 an intense action proceeds as the sulphides become bessemerised4 ,the heat of oxidation of iron sulphide has long been known to be very great1 and ,holway pointed out that this heat corresponds to the large quantity of heat which is developed by the free roasting of heavy sulphides1 compressed into the space of a few moments1 and thus results in an exceedingly great intensity with consequent high temperature4 ,sulphur is burnt out to ,,so#b1 iron is converted to the oxide which instantly combines with the white-hot silica skeleton that is present and forms an iron-silicate slag1 evolving still more heat4 ,this slag1 with the enriched matte1 melt thoroughly at the prevailing temperatures1 and issue from the slag spout of the furnace4 ,the work of ,sticht and ,peters thus allow of the mechanism of the processes being followed during the passage of the materials through the furnace4 ,at the ,mount ,lyell ,smelter1 where ,sticht operated1 the charge extends about #ab feet above the tuyeres4 ,in the upper #f or #g feet1 elemental sulphur is driven off from the pyritic materials by the effects of heat alone1 and the furnace gases in this zone consist chiefly of nitrogen1 ,,so#b 7from the bessemerising71 sulphur vapour1 a little ,,co#b1 but practically no free oxygen4 ,about half-way down1 the temperature is sufficiently high to melt out the fusible sulphides from the charge2 these liquate and trickle unchanged through the still solid masses of gangue and silica-flux1 until they meet with free oxygen of the air blast1 when they are oxidised and burnt up with great rapidity and with the evolution of intense heat4 ,this bessemerising zone extends from a short distance above the tuyeres to a point where all the oxygen is used up by the iron and sulphur4 ,the distance is variable1 but is probably some #b feet or so4 ,at this level the ferrous oxide produced is instantaneously seized by the white-hot particles of free silica with the production of a silicate slag1 the composition of which corresponds to the silicate whose formation temperature is equal to that prevailing in this bessemerising zone4 ,control of the ,operations4--,it has thus been established that the oxygen of the air blast entering the furnace through the tuyeres is practically all expended in this bessemerising of the liquated sulphides in the narrow bessemerising zone1 and that it does not operate at all by any roasting reactions in the upper part of the furnace1 as had been formerly supposed4 ,from this knowledge it therefore becomes possible to indicate the essential factors which control the successful operation of true pyritic smelting4 ,the degree of bessemerising depends upon the amount of air supplied for the oxidation of the sulphides1 and upon the quantity of siliceous flux present to slag off the iron oxide produced4 ,the actual smelting takes place at the focus where the liquated sulphides are instantaneously bessemerised1 and the more rapid this oxidation1 the more intense are the reactions and the higher the temperatures which result4 ,for successful pyritic smelting it is1 therefore1 essential that there shall be present-- 7a7 ,sufficient sulphides in the charge to give out the heat necessary for the smelting and for the thorough fusion of the products4 7b7 ,sufficient oxygen 7air7 for the rapid and necessary oxidation of this sulphur and iron4 7c7 ,sufficient free siliceous flux for the satisfactory slagging of the iron oxides produced4 7a7 ,the supply of heat required for the smelting of the charge and the thorough fusion of the products depends entirely on the intense combustion of the iron and sulphur constituents1 and the greater the proportion of these materials oxidised per minute1 the higher is the temperature4 ,as has been already noted1 such heat intensity increases at a rate greater than the mere arithmetical increase in the fuel proportion1 by reason of well-known thermo-chemical laws regarding mass effects4 ,indirectly1 too1 the higher the proportions of sulphides present1 the smaller is the quantity of inert or useless matter which requires to be heated and slagged off in the furnace--apart from the question of the necessary flux material4 ,hence the higher the iron and sulphur contents of the ore1 the more successfully may true pyritic smelting be applied to it4 ,true pyritic smelting may be said to cease when carbonaceous fuel requires to be burnt at the tuyere zone in order to supplement the heat derived from the sulphides1 and broadly speaking1 from about #bh per cent4 of iron and about #cj per cent4 of sulphur are necessary in the charge for good pyritic work under present conditions4 ,at ,tennessee1 with about these proportions1 the coke consumption on the charge is reduced to about #c to #d per cent42 at ,mt4 ,lyell1 where the ore runs from #dj per cent4 of iron with a corresponding quantity of sulphur1 the coke consumption amounts to only about #abe per cent4 ,none of this coke probably reaches the bessemerising zone at all4 7b7 ,being supplied with enough sulphide fuel1 the requisite quantity of air for the rapid and sufficient combustion of this iron and sulphur is essential4 ,the oxygen is used up entirely in the bessemerising of the sulphides at the tuyere zone of the furnace1 and in consequence1 not only the heat supply1 but also the concentration depends upon the amount of oxygen furnished at this point1 since the greater the quantity of oxygen which is used up1 the greater is the amount of sulphur eliminated and the amount of iron oxidised and slagged off1 and in consequence1 the higher is the proportion of copper in the resulting matte4 ,in other words1 the oxygen supply largely controls the concentration effected in the smelting process1 and consequently an adequate quantity is of the utmost importance4 ,the amount of air theoretically required per minute is readily calculated from the estimated capacity of the furnace and from the charge analysis4 ,liberal allowances are required for losses1 leakages1 blower efficiency1 etc42 and the volume necessary at the furnace amounts to something like #e1jjj cubic feet per minute per #ajj tons of sulphide4 7c7 ,sufficient siliceous flux is required for the satisfactory slagging of the iron oxides produced4 ,the presence of the requisite silica on the charge is exceedingly important4 ,the iron of the sulphides1 upon oxidation by the air blast1 is converted into iron oxides1 primarily ,fe,o4 ,this oxide is incapable of existing by itself1 but possessing when nascent a powerful affinity for silica at high temperatures1 it produces ferrous silicates1 which are1 in the main1 fusible slag-like products4 ,this action is particularly evident in the tuyere zone of the pyrite furnace1 where the silica is present in a white-hot condition4 ,if sufficient silica be not present to combine with the iron oxide produced1 the ferrous oxide which is exceedingly unstable1 finding itself without the necessary flux1 is converted under the continued oxidising effect of the blast into higher oxides of iron such as ferric oxide or magnetic oxides1 materials which are practically infusible1 and this results in the production of an infusible sinter which leads to the choking of the furnace4 ,on the other hand1 if excess of silica be present in the charge1 highly siliceous and unworkable products result1 which will not run out of the furnace4 ,any further excess of silica simply remains unfused and unattacked1 and causes the ultimate stoppage of the furnace operations4 ,the silica for fluxing is consequently an important factor in controlling the running of the pyritic furnace1 and the provision of the requisite quantity1 as nearly as possible1 is essential1 since otherwise the presence of adequate sulphide and air blast is not in itself sufficient to ensure satisfactory working4 ,the actual quantity of silica required is determined by the factor known as the formation temperature of the silicates4 ,every silicate has a definite formation temperature--i4e41 a definite mixture of iron oxide and silica requires a definite temperature in order that complete combination may occur and a chemical compound silicate be formed4 ,conversely1 at any definite temperature1 only those silicates having a corresponding formation temperature to this degree of heat can be produced4 ,in consequence1 if the oxidation of the sulphides at the tuyere zone produces any particular temperature1 that particular silicate whose formation temperature corresponds to this will tend to be formed1 and the required quantity of free silica must be present to yield this definite silicate with the whole of the iron oxidised4 ,only a limited quantity of silica can thus be taken up for any definite rate of oxidation of iron sulphide1 and the presence of either more or less silica does not greatly affect the composition of the slag4 ,thus the concentration 7sulphide oxidation7 is primarily dependent on the oxygen supply1 which determines how much iron shall be burnt1 but the success of the operation depends upon the presence of the correct amount of silica to flux off this iron oxide4 ,this proportion is fixed by the temperature attained at the tuyere zone1 which restricts the silicate produced to such a composition that its formation temperature coincides with this degree of heat4 ,hence the general law has been deduced and has been confirmed in practice1 that 8a pyritic furnace produces a slag corresponding in composition to the silicates whose formation temperature equals that prevailing at the tuyere zone10 accounting for the well-known observation 8that the pyritic furnace tends to make its own slag40 ,if the smelting operation is to proceed satisfactorily1 slag approaching this composition will be produced1 and assuming the air supply to be adequate for the purpose1 the absence of the requisite silica on the charge affects the quantity rather than the character of the slag4 ,the amount of iron sulphide oxidised depends largely upon the presence of silica to combine with the iron oxide produced2 so much will be oxidised as the silica can deal with1 and in consequence1 if the free silica supply is deficient1 a smaller quantity of slag is formed1 whilst the matte will be larger in amount but of lower grade4 ,an addition of silica to the furnace charge under such circumstances would thus raise the grade of the matte by encouraging the slagging of more iron1 and would produce slag of approximately the same composition as before1 though in larger quantity4 ,deficiency of silica also results in the production of over-fire1 owing to the fact that the air blast1 being unable to bessemerise any more iron sulphide at the tuyere zone1 passes to the higher portions of the furnace and gradually roasts the ore there1 thus consuming the sulphide fuel of the furnace which might otherwise be most effectively used for bessemerising in the tuyere zone4 ,this over-fire1 resulting from the heat of roasting which is given out in the upper part of the furnace1 is very disadvantageous in true pyritic smelting1 and successful control of the process depends on using up the whole of an adequate air supply at the bessemerising zone1 and on supplying sufficient siliceous flux to combine at once with the whole of the iron oxide produced4 ,for fluxing purposes it is only the free silica in the charge which is effective1 since any silica existing as silicate is already in a state of combination and thus is not free to act as flux4 ,the combined silica1 except for its adding to the fusibility of the charge by admixture1 is very disadvantageous1 consuming heat and space1 diluting the reaction intensities by presenting an inert substance among the active constituents1 and increasing the quantity of slag which requires to be melted4 ,the three requirements--iron sulphide1 oxygen supply1 and fluxing silica--thus bear an intimate relationship to one another in true pyritic smelting1 and alteration of any one factor requires simultaneous adjustment of the others for the production of the same grade of matte and slag4 ,the speed and degree of oxidation primarily depend on the air supply4 ,the more iron burnt up1 the greater is the heat production and the higher the temperature at the tuyere zone1 and since the more basic slags are known to have the higher formation temperatures1 the basicity of the slags increases with the speed of oxidation and consequent concentration4 ,ores suitable for true pyritic smelting are not commonly met with in practice1 and the presence of earthy bases other than iron is not desirable4 ,whilst the advantages of polybasic slags from the point of view of reduced formation temperature1 increased fusibility and liquidity are very marked in ordinary smelting practice1 their presence is not so advantageous in true pyritic smelting1 since they consume silica which is required for the iron oxide at the instant of formation1 and thus tend to decrease the speed of oxidation and concentration4 ,polybasic slags have a lower formation temperature1 and in consequence the production of the highly ferruginous slags of high formation temperature which it is desired to make by the oxidation of as much iron as possible is retarded4 ,in addition1 the presence of other earthy bases in the charge dilutes its fuel value2 they may even consume valuable heat by requiring decomposition1 as in the case of carbonates4 ,these considerations are not so important in partial pyritic smelting1 where the required heat balance can be adjusted by coke4 ,the ,advantages of ,pyritic ,smelting4 7#a7 ,the possibility of direct and immediate treatment of highly pyritic raw ore in the blast furnace1 thus saving all the costs of preliminary treatment and handling4 7#b7 ,the saving of the costs of roasting heavy sulphides4 ,in former smelting practice1 high sulphide contents in a copper ore were particularly disadvantageous1 since the higher the sulphur contents of the charge the lower was the grade of the resulting matte1 when smelted directly in the blast furnace4 ,in consequence1 the higher sulphur content necessitated a more complete roasting of the ore in order to ensure a high-grade matte on smelting4 ,with pyritic smelting the conditions are completely reversed1 and the charge becomes more suitable for direct furnace treatment as its sulphide contents increase1 so that the most suitable ores for pyritic smelting are those in which the greatest saving is effected by their not requiring a preliminary roasting operation4 ,as has been already indicated1 this saving includes labour1 plant1 handling1 time1 and interest on capital tied up in the roast yards1 as well as the avoiding of all the mechanical and other losses connected with such preliminary treatment4 ,thus at ,ducktown1 ,tennessee1 the material economies effected by the substitution of pyritic smelting for the processes involving preliminary roasting amounted to no less than #c to #d cents per pound of copper produced1 in addition to the later advantages derived from the recovery of values from the gases1 and from the improved conditions of life in the district4 7#c7 ,the cost of coke is saved4 ,fuel is one of the main items of expense in blast-furnace smelting1 and by the substitution of the cost-free natural-sulphide fuel for coke1 the proportion of the latter required on the charge is reduced from the #i to #aj per cent4 formerly employed with roasted materials to about #c to #e per cent41 and in certain special cases to very much smaller amounts4 ,difficulties of the ,process4--,that the technical difficulties in applying the process on a practical scale are considerable1 under present conditions of working1 will be understood from the nature of the operations4 7#a7 ,the pyritic process works on a narrow margin of heat1 and allows of but little flexibility in the conditions of working1 since there are few factors which can be altered should difficulties in operating arise1 as compared with the circumstances when a free use of supplementary carbonaceous fuel may be employed4 ,the only source of heat energy at the smelting zone is in the sulphide charge itself1 and small variations in the working conditions may readily disturb the delicate equilibrium upon which successful working depends4 ,irregularities1 stoppages1 and variations in grade of matte may therefore arise1 unless the operations are regulated with exceeding watchfulness4 ,in true pyritic smelting the employment of coke for restoring the balance or for producing heat required at the tuyere zone is not permissible or practicable1 since1 as will be indicated later1 such coke addition would altogether destroy the equilibrium in the process2 the grade of matte and the composition of slag would be altered1 the reactions disturbed1 and a restoration to normal pyritic smelting conditions rendered almost impossible4 ,difficulties in operation have therefore to be overcome along the lines of pyritic action--that is1 in the further adjustment and manipulation of blast1 sulphide or silica supply1 or in charging methods1 etc4--and in practice such careful 8doctoring0 is resorted to when the furnace shows signs of working unsatisfactorily4 ,it is very often possible by such careful attention to gradually bring a furnace back to smooth running4 ,it occasionally happens1 however1 that the conditions gradually become worse1 and the furnace commences to show signs of 8gobbing40 ,this is indicated at the top of the charge by the formation of crusts round the side and end walls1 whilst from the slag spout below1 there issues a much reduced quantity of thick siliceous slag1 together with an abundant stream of thin low-grade matte4 ,the furnace gradually ceases running1 and it becomes necessary to stop its working1 to take down the furnace jackets1 bar out the debris1 and restart operations4 ,this is usually not so objectionable a procedure as it might appear1 and indeed1 within certain definite limits1 such a course may economically be sound policy4 ,in the modern operation of pyritic practice it often pays better to risk the occasional gobbing up of a furnace and clear out the debris1 than to work with so large a quantity of coke as would avoid such a necessity4 ,not only is the modern furnace so designed and constructed as to entail but comparatively little trouble in cleaning out in this manner1 but such practice1 even if temporarily a necessary evil1 may1 in places where coke is expensive1 and where conditions for pyritic smelting are otherwise favourable1 be1 within certain definite limits1 actually the most profitable4 ,it is by the taking of these risks1 combined with further experiment and working experience in manipulation1 such as in charging methods1 blast conditions1 and the height and distribution of charges1 etc41 that the ultimate continuous and successful working at still lower costs may be attained and the true pyritic process be worked as continuously as ordinary smelting practice4 ,short campaigns are not1 therefore1 unusual under the present conditions of true pyritic smelting1 and the cleaning out of the generally fairly loose debris is accomplished with moderate ease1 from #bd to #cf hours being the usual time required to take down1 clean out1 and restart a furnace1 whilst the cost of such an operation 7chiefly in labour7 is not1 under the circumstances1 excessive4 ,at ,tennessee1 hard driving and short campaigns result in lower costs and greater tonnage4 7#b7 ,the composition of the slag often prevents high concentration4 ,it has been indicated that the thermal conditions in the bessemerising zone of the pyritic furnace tend to the production of highly basic slags1 which1 though hot and limpid1 are characterised by high density4 ,such slags are not conducive to good settling and separation of mattes1 and they tend to occasion high copper losses1 because-- 7a7 ,the difference in density of slag and matte is not sufficiently great4 7b7 ,the solubility of sulphides in the slag increases with its basicity4 ,the greater the concentration effected by the smelting operation1 the higher is the grade of the matte produced2 at the same time1 the actual weight of matte is smaller4 ,on the other hand1 since more iron is oxidised from the charge and slagged off1 the quantity of slag produced increases proportionately4 ,contrasting then1 the likely losses of copper which would result from the association of a small quantity of high-grade matte with much slag1 compared with those resulting from the association of a considerable quantity of low-grade matte in the presence of but little slag1 the former condition is obviously the more productive of heavy loss1 for not only will many more shots of matte be held in suspension1 but each shot of high-grade matte represents a larger quantity of copper4 ,it is found in practice that it is most economical to make a fairly low-grade matte on the first or 8green-ore0 smelting1 and to re-concentrate this matte pyritically up to converter grade by a second smelting operation4 ,the extra cost of casting the low-grade matte1 of breaking up1 rehandling it1 and resmelting1 with all the extra charges on capital1 etc41 involved1 is less than the losses which would be incurred if higher-grade converter matte were made at the first smelting1 although there is no difficulty at all in producing such mattes so far as the actual furnace operations are concerned4 ,it is entirely a question of the slag losses involved4 ,under ordinary smelting conditions 7not truly pyritic71 when using some coke for fuel1 it would be readily possible to alter the density of the slag by adding suitable constituents1 such as limestone or additional silica1 but in pyritic smelting this is not practicable4 ,the furnace chooses to make at the tuyere zone its own slag1 and that a highly basic one4 ,high concentration and a slag low in iron content cannot be obtained together in true pyritic smelting1 since high concentration means rapid oxidation of iron sulphide1 and this necessitates high temperature and produces a highly ferruginous slag in consequence4 ,additional silica added to the charge could not alter the slag composition markedly and still yield the same grade of matte4 ,the silica content of the slag depends on the temperature at the tuyere zone1 and this is governed by the rate of oxidation of the iron sulphide4 ,if the slag is to be more siliceous it must be produced at a lower temperature1 which would be obtained by oxidising the iron less rapidly4 ,this would lead to the production of low-grade matte1 and probably would so reduce the furnace activity that there would not be sufficient heat to keep the slag molten4 ,if extra silica be added to the charge1 it would probably be unattacked unless more iron were oxidised in order to flux it off4 ,in such a case the blast would have to be increased in order to produce iron oxide more rapidly1 the temperature would in consequence be raised1 a still more basic slag would be produced in larger quantity1 whilst the matte would be increased in grade and reduced proportionally in weight4 ,the addition of sufficient lime to the charge1 in order to produce a sufficiently low-gravity slag1 is also impracticable in true pyritic work1 because-- 7a7 ,the extra lime consumes silica1 and interferes with the desired reactions at the bessemerising zone1 tending to lower the concentration4 ,it also absorbs heat4 ,lime has a very powerful affinity for silica1 more strongly marked than that of iron oxide1 its replacing value is higher1 its more siliceous silicates are readily formed and they have a lower formation temperature1 all of which factors tend to an undue consumption of silica which is urgently required by the iron if the rate of oxidation is to be maintained4 ,the marked tendency for lime in the charge to consume the silica tends to retard the oxidation of the iron sulphide1 which proceeds most satisfactorily when free silica is available for the nascent iron-oxide1 and in consequence concentration is decreased and the heating effect in the furnace reduced4 ,in addition1 the larger bulk of calcareous slag carries considerable heat from the smelting zone of the furnace4 ,lime silicates and the polybasic lime slags have a markedly lower formation temperature than the normal ferruginous slags of true pyritic smelting1 they are hence formed readily without requiring so much oxidation activity at the tuyere zone4 ,in consequence less iron is oxidised1 and the resulting concentration in the matte is proportionately reduced4 7b7 ,the lime is introduced in the form of limestone1 and the carbon dioxide liberated from this material in the furnace is found to have a deleterious effect on the furnace gases if the manufacture of sulphuric acid from them is intended--this being a consideration of great economic importance in connection with many modern pyritic smelters4 ,hence1 in practice1 pyritic smelting is at present generally conducted in two stages for the production of a matte of #cj1 #dj1 or #ej per cent4 converter grade4 ,the 8green ore-matte10 or first matte1 runs usually from #h to #ac or #ad per cent4 of copper1 depending upon the copper ore available1 which is usually very low grade--#b to #c per cent4 copper contents2 the second or concentrated matte assays #bh to #dj per cent4 copper4 ,special care is taken to ensure good settling of matte from the basic and irony slags1 and by these means the copper losses in the slags are reduced to the comparatively moderate proportions associated with normal practice4 ,it does not appear improbable that with the developments of basic converter practice1 involving eventually the continuous converting of low-grade mattes1 the necessity for this second pyritic smelting and re-concentration may be avoided4 ,the removal of this feature from pyritic smelting practice would add enormously to the potential economies arising from the method4 ,in spite of the difficulties connected with the process1 as detailed above1 the method has proved itself an exceedingly profitable one on a large scale1 and the experience of the companies financially interested1 as well as the opinions of managers of the plants in practical operation1 leave no doubt as to the economic success of this application of scientific principles to a practical problem on a very extended scale4 ,,special ,,features ,,of ,,pyritic ,,smelting4--,several points of particular interest have given rise to much discussion in connection with pyritic smelting practice4 ,these include the question of the coke proportion required on the charge1 and the advisability or otherwise of employing heated blast for the furnace4 ,coke ,proportion4--,whilst ideal pyritic practice involves the entire absence of supplementary carbonaceous fuel1 it has not been found practicable1 up to the present1 to ensure satisfactory working over any reasonable period of time1 unless a minimum of about #abe per cent4 of coke is incorporated with the charge4 ,the function of this coke has been a matter of much speculation1 but the investigations of ,sticht already referred to1 now permit the tracing1 with some considerable accuracy1 of its function and of its action in the furnace4 ,it is found that in true pyritic smelting the coke does not reach the bessemerising zone at all1 but that it is completely consumed in the regions above this point4 ,it is1 moreover1 not burned by the oxygen of the air1 none of which exists above the tuyere zone1 since all this oxygen is consumed by the combustion of the sulphide4 ,it appears that the coke is oxidised by the ,,so#b which results from this sulphide combustion4 ,the examination and analysis of samples of the gases withdrawn from different parts of the furnace have confirmed this view1 and have elucidated the probable reason for the apparent necessity of a certain small proportion of coke in the process1 under the present conditions of working4 ,the heat generated from the oxidation of the coke by the ,,so#b is of much value in preheating the materials of the charge for the removal of excess sulphur and the liquation of the sulphides4 ,the amount of heat which is available for this operation is small1 being practically all derived from that carried upwards by the hot gases leaving the smelting zone1 and none is obtainable by the usual processes of coke or sulphide oxidation in the upper regions of the furnace1 since no available oxygen is believed to get past the bessemerising zone and reach these upper areas4 ,it is indeed necessary for the success of pyritic smelting that such oxidation or roasting of sulphides in the upper part of the furnace should be prevented1 since every available particle of iron sulphide is required for heat production at the smelting zone1 by its combustion there1 and any oxidation elsewhere not only deprives this zone of fuel1 but spreads the heat over too wide an area for sufficiently intense combustion4 ,thus1 by supplying an additional amount of heat to the upper parts of the furnace1 where heat is needed to assist in the preparation and liquation of the sulphides1 the extra coke1 in being oxidised by the ,,so#b without robbing the tuyere zone of fuel or air1 just fulfils its useful purpose at the required place1 in such a way as to keep the smelting operation running smoothly4 ,the presence of more coke than is absolutely necessary for the fulfilment of this purpose is1 in addition to its extra cost1 of no advantage1 and in true pyritic smelting none should reach the tuyere zone1 since it introduces a reducing influence where the most marked oxidising effect is required4 ,by consuming oxygen for its combustion1 it deprives the iron sulphide of this material1 less iron is1 therefore1 oxidised1 and the matte is consequently increased in quantity and lowered in grade1 whilst the amount of iron carried into the slag is decreased4 #abe per cent4 of coke is about the minimum quantity with which it is found practicable to maintain satisfactory working of the furnace under present conditions1 #je per cent4 has been worked with occasionally1 and none at all over certain short periods of time4 ,the average quantity employed is from #b to #c per cent41 and when about #e per cent4 is used1 coke reaches the tuyere zone and the process ceases to be truly pyritic--the reactions and smelting conditions become entirely changed4 ,it does not seem unlikely that1 as knowledge of these conditions increases and as the mechanism of the process becomes more generally understood1 modifications in furnace design and blast conditions may lead to the successful operating of the pyritic process entirely independent of the use of coke fuel4 ,heating of the ,blast4--,for true pyritic smelting it has been shown in practice that the use of heated blast possesses no advantages2 many smelters operating the process have tested the effects1 and have usually given the method up1 whilst the work of ,sticht and ,peters affords valuable evidence and close argument as to the reasons for its unsuitability4 ,success in true pyritic working depends upon the intensity of oxidation of the sulphides1 and upon the localisation of the resulting heat at the narrow bessemerising zone situated just above the tuyeres4 ,the greater the quantity of iron which is there oxidised per minute1 the better is the concentration1 the greater is the smelting and fluxing intensity and the higher is the resulting temperature4 ,since the character and composition of the slag vary in accordance with these conditions1 depending largely upon the temperature in the tuyere zone1 the furnace works most rapidly and satisfactorily when slags of high formation temperature are being produced4 ,these can only be formed if much iron is being oxidised1 because iron is the chief fuel in the process4 ,the addition of extra heat by warming the blast appears to allow of the formation of silicate slags possessing a lower formation temperature1 such slags are less basic1 and consequently less iron need be oxidised and slagged off per minute in order to produce them4 ,less iron sulphide fuel is1 therefore1 burned1 and the reaction intensity at the tuyere zone is reduced1 so that the necessary heat margin for satisfactory smelting may not be attained4 ,the extra heat carried in by the warmed blast may not be sufficient to compensate for that which is lost owing to this decrease in oxidation intensity2 the furnace consequently tends to work cold1 whilst the excess air supply leads to the production of over-fire1 by the oxidising of sulphides higher up in the charge4 ,these features are specially interesting1 as they afford one of the most marked distinctions between true and partial pyritic smelting4 ,in the latter process1 the fuel value in the adjustable supply of coke at the tuyeres allows of the ready production of any extra heat which might be required4 ,the slag composition is1 in consequence1 more independent of the furnace conditions1 since the heat required for the smelting operation does not depend so much on the formation of slag of any particular composition4 ,sufficient heat is always obtainable by coke additions when smelting for any special slag which may be desired4 ,neither is localisation of the heat at the narrow tuyere zone so essential in partial pyritic smelting4 ,warm blast produces a greater combustion intensity when employed in oxidising carbon1 so that it may present advantages1 both economic and operative1 in partial pyritic work1 whereas it is distinctly disadvantageous in the true pyritic method4 ,pyritic ,smelting ,practice in ,tennessee4--,the pyritic process is operated in ,tennessee at two smelters2 that at ,copperhill under the ,tennessee ,copper ,company1 and at ,isabella by the ,ducktown ,sulphur1 ,copper and ,iron ,co4 ,the ore averages from #b to about #b per cent4 copper1 #ca to #cg per cent4 iron1 #bj to #cj per cent4 sulphur1 #aj to #be per cent4 silica1 the remainder being earths1 including lime about #f per cent41 magnesia #b per cent41 zinc #b per cent41 and alumina--i4e41 a heavy sulphide ore with but little excess of free silica available for the fluxing of iron4 ,copperhill4--,the process is conducted very much according to the principles just considered4 ,the ,copperhill plant operates seven furnaces of the ordinary rectangular water-jacketed type--the general features of furnace design being little different at present1 whether true or partial pyritic practice be conducted4 ,several important devices in detail have been introduced with successful results1 and the management is distinguished for its pioneer work and experimental enterprise in connection with the process4 ,the furnaces were formerly all #ef inches wide2 three of them are #ahj inches long1 the other four being #bgj inches4 ,the height of charge is from #aj to #ab feet1 the capacity of the smaller furnaces #cge to #djj tons of charge daily1 and a blast of #ai1jjj cubic feet of air per minute at #ej ozs4 pressure is supplied to each4 ,the larger furnaces have a capacity of #ejj to #fjj tons daily4 ,many trials have been made to determine the best shape for the water-jacketed sections1 both broad and narrow panels having been employed4 ,in one of the furnaces1 curved end-jackets were tried1 with the object of lessening the production of crusts which tend to form at the corners1 owing to coldness and reduced furnace activity at these points4 ,the advantages expected have not been realised1 the tendency to crusting has not been lessened1 and although barring has been rendered easier1 the disadvantages of rounded corner-jackets and their greatly increased cost of construction outweigh their advantages1 and their use has now been given up4 ,illustration3 ,fig4 #fa4--,slotted ,tuyeres1 #ab inches by #d inches 7,t4 ,c4 ,c474 ,an important modification in the form of the tuyeres has been introduced with the object of furnishing more effectively the necessary large volume of air at suitable pressure1 and of increasing the efficiency at the tuyere zone4 ,instead of supplying the air to the furnace at a number of separated points1 it was felt that the closer these could be brought together the better4 ,a narrow slot all round the furnace for air admission has been held to be the most perfect method1 but hitherto it has been thought impracticable1 though a recent form of furnace 7not at this plant7 has been devised on this system4 ,the improvement here has been the use of slotted tuyeres1 #ab inches long by #d inches wide1 each of which replaces two of the older tuyeres of #c inches diameter4 ,these have proved very successful1 the furnace thus equipped handling a much larger tonnage1 and it has been decided to adopt the new form on all the furnaces4 ,charging is by side-dumping ,v-shaped cars1 and great care is taken in the handling and distribution of the charges4 ,the furnaces are fitted with tops of special design1 and with elaborate dust-catching devices which have been the subject of long and numerous experiments2 the special purpose being to allow the taking off of the gases below the feed-floor1 and to reduce the height of the superstructure to the smallest possible proportions1 so as to prevent excessive dilution 7by air7 of the furnace gases1 which are used for sulphuric acid manufacture4 ,the furnace tops were originally of the standard form--brick walls supported by steel frame-work4 ,it was1 however1 necessary to damper down the flues in order to obtain sufficient pressure to force the gases through the ,glover towers1 and the heat has caused the steel work to warp badly4 ,a low top was tried1 using a brick-lined flue at the end for taking off the gases below the feed-floor4 ,this was found to be good for charge-dumping and general convenience1 but it allowed the escape of too much smoke and flames1 which greatly interfered with the furnace manipulation4 ,in consequence the tubular top was used1 gradually raised until a suitable height was reached4 ,this form has been described on p4 #adj4 ,the present practice at ,copperhill is to smelt the ore pyritically for a #i to #aj per cent4 matte1 passing the products through the #af-;foot settlers which are now lined with siliceous copper ore1 then tapping the matte into ladles which empty it into beds of flue-dust4 ,alternate layers of matte and dust are thus incorporated1 and yield a porous material convenient for the concentrating pyritic smelt which follows4 ,this re-concentration is now conducted in a furnace narrowed to #dd inches1 which has been found specially well suited for the work2 the furnace runs fast1 smelting sometimes over #hjj tons of charge per day4 ,the system of working is that of hard driving so long as the furnace smelts rapidly4 ,as soon as it slows down1 the furnace is tapped out and started afresh4 ,the re-concentrating charge contains some limestone in order to reduce the copper losses in the slag1 the saving effected by this feature being equivalent to #b lbs4 of copper per ton of ore smelted4 ,the resulting matte is bessemerised4 ,the furnace gases are utilised for sulphuric acid manufacture1 the acid plant being the largest in the world1 with an ultimate capacity of #djj tons per day4 ,ducktown4--,it was at the ,ducktown ,company's smelter that the first work on pyritic smelting in the district was carried out1 and the successful development of the process generally1 owes much to ,freeland's early pioneer work1 the remarkable results of which led ,parke-,channing to adopt the process at the ,copperhill plant4 ,,table ,,xi4--,,typical ,,charging ,,tables ,,at ,,pyritic ,,smelter4 ,b4,f4 ,,no4 #c--,,night ,,shift4 ,typical ,green ,ore ,charges4 ,i4 ,,ii4 ,,iii4 ,,iv4 ,lbs4 ,lbs4 ,lbs4 ,lbs4 ,coke1 #ahj #bdj #bdj #djj 44 ,ore ,a41 #e1jjj 44 44 44 44 ,ore ,b41 44 #e1jjj 44 44 44 ,ore ,c41 44 44 #e1jjj 44 44 ,slag1 44 44 44 #d1jjj 44 ,lime rock1 44 44 44 44 44 ,green ore 7low grade7 matte1 44 44 44 44 44 ,flue-dust1 44 44 44 44 44 ,quartz 7for flux71 #iej 44 44 44 44 ,total weight of charge1 #f1acj #e1bdj #e1bdj #d1djj 44 ,no4 of ,no4 of ,no4 of ,no4 of ,total ,hours of ,charging-- ,charges,charges,charges,chargesper ,hr #f-g1 #b #b 44 44 #d #g-h1 #b 44 #b #b #f #h-i1 #b #b 44 44 #d #i-aj1 #b1 #b 44 #b1 #b 44 #h #aj-aa1 44 #b 44 #b #d #aa-ab1 #b 44 #b 44 #d #ab-a1 #b1 #b #b 44 44 #f #a-b1 #b 44 #b #b #f #b-c1 #b #b 44 44 #d #c-d1 #b 44 #b 44 #d #d-e1 #b 44 44 #b #d #e-f1 #b1 #b #b #b 44 #h ,total ,no4 of charges daily1 #bh #ab #ad #h #fb ,b4,f4 ,,no4 #e--;,,day ,,shift4 ,typical ,concentrating ,charges4 ,i4 ,,ii4 ,,iii4 ,lbs4 ,lbs4 ,lbs4 ,coke1 #aej #djj extra #gjj 44 ,ore ,a41 44 44 44 44 ,ore ,b41 44 44 44 44 ,ore ,c41 44 44 44 44 ,slag1 44 #d1jjj 44 44 ,lime rock1 #gjj 44 44 44 ,green ore 7low grade7 matte1 #c1ejj 44 44 44 ,flue-dust1 44 44 44 44 ,quartz 7for flux71 #a1jej 44 44 44 ,total weight of charge1 #e1djj #d1djj #gjj 44 ,no4 of ,no4 of ,total ,hours of ,charging-- ,charges ,charges per ,hr #f-g1 #b1 #b1 #b1 #b1 #b1 #b1 #b 44 44 #ad #g-h1 #b1 #b1 #b1 #b #b 44 #aj #h-i1 #b1 #b1 #b1 #b1 #b 44 44 #aj #i-aj1 #b1 #b1 #b1 #b1 #b 44 44 #aj #aj-aa1 #b1 #b #b1 #b1 #b1 #b 44 #ab #aa-ab1 #b1 #b1 #b1 #b1 #b 44 44 #aj #ab-a1 #b1 #b1 #b1 #b1 #b 44 44 #aj #a-b1 #b1 #b1 #b1 #b1 #b 44 44 #aj #b-c1 #b1 #b1 #b #b1b 44 #aj #c-d1 #b1 #b1 #b1 #b1 #b1 #b 44 44 #ab #d-e1 #b1 #b1 #b1 #b1 #b 44 44 #aj #e-f1 #b1 #b1 #b #b1 #b1 #b1 #b 44 #ad ,total ,no4 of charges daily1 #abj #ab 44 #acb ,it will be observed that the concentrating furnace works twice as quickly as the green ore matting furnace1 and hence one furnace only is required for the concentration of the matte product from two of the matting furnaces4 ,the ,isabella smelter comprises two furnaces of moderate size1 #ag feet by #c feet #d inches at the tuyeres1 having a joint capacity of #ejj to #fjj tons daily4 ,the furnaces are about #i feet high1 and are water-cooled4 ,air at only #bj to #cj ozs4 pressure is supplied through #c-;inch tuyeres4 ,the smelting scheme is somewhat analogous to that adopted at ,copperhill1 the first smelting producing a #bj per cent4 copper matte from the #b per cent4 ore1 whilst the re-concentration results in a converter-grade matte assaying #ej per cent4 ,the coke proportions are somewhat similar to those used at ,copperhill1 being #ej per cent4 for the first smelting1 and #ce per cent4 for the second4 ,the furnace management at this small plant is exceedingly efficient1 and the campaigns are long1 it being claimed that the furnace operations have never had to be completely stopped on account of crusting or gobbing4 ,this is held to be due to the results of special care in feeding and charge distribution1 the ingenious ,freeland charger already described being used4 ,the charge is kept low 7#f to #h feet above the tuyeres71 and is evenly red hot all through4 ,the slags assay #ce to #cf per cent4 silica1 #chh per cent4 iron1 and #hj per cent4 lime--with moderate copper losses4 ,the annual output is equivalent to about #c1jjj tons of metallic copper4 ,an acid-making plant is also attached to these works4 ,the ,manufacture of ,sulphuric ,acid from ,pyritic ,furnace ,gases4--,modern legislative requirements make severe demands upon the managements of smelter-works where sulphury ores are dealt with1 by reason of the disastrous effects of the sulphurous gases upon the conditions of life generally in the vicinity4 ,in other cases1 litigation by neighbouring farmers and others impose restrictions on the amount and character of the gases which the smelters are allowed to emit from their furnace stacks4 ,so serious has the problem become that several smelters have had to cease operations altogether1 others have been mulcted in enormous costs by law suits1 by claims for compensation1 or by the installation of plant and processes which they have been compelled to adopt for dealing with the gases4 ,these matters have become subjects of historical importance in the development of smelter practice4 ,as has been the case in analogous circumstances elsewhere1 when interference with the uncontrolled dispersion of then-considered waste products has often proved of ultimate benefit and a source of much profit to their producers1 the enforced treatment of highly sulphurous furnace gases has in several instances resulted in considerable gain to the copper smelters4 ,among the methods which are at present economically practicable for dealing with the smelter gases1 those of dilution1 and of utilisation for acid manufacture are the most important4 ,the considerations which decide the best course of treatment depend on the numerous economic and local factors which are always of such prime importance in connection with industrial undertakings demanding large capital outlay4 ,the installation of a plant for making sulphuric acid from the gases largely depends on-- 7a7 ,the technical factor as to whether the composition of the gases is suitable for the making of acid4 7b7 ,the economic factor as to whether such acid can be put upon the market on a satisfactory basis4 7a7 ,for the successful operation of acid-making plant1 as at present developed1 it is necessary that the proportions of sulphur dioxide in the gases shall not fall below a certain minimum1 and further1 that the gases shall not contain more than certain limiting proportions of other interfering constituents1 such as1 for instance1 ,,co#b4 ,it is for this reason that the blast furnace operating the true pyritic process furnishes gases of the type most suitable for acid manufacture1 since by this process the sulphur-dioxide is obtained in the gases in the most concentrated and the least contaminated form possible under smelting conditions4 ,even under these circumstances the gases are not in the least of an ideal composition for treatment1 owing to their dilution with nitrogen1 etc41 and the development of the acid-making plants and processes adopted for the successful utilisation of copper blast-furnace gases furnishes a record covering many years of very slow and costly experiment1 marked by many preliminary failures and disappointments4 ,these difficulties have now been overcome1 as the working of the successful plants attached to both of the ,tennessee copper smelters affords conclusive proof1 and the sulphur which formerly cost money to dissipate by roasting1 now not only acts as fuel1 but furnishes a very profitable bye-product4 ,the requirements for the gases are chiefly the presence of sufficient ,,so#b and oxygen1 and of as little ,,co#b as possible--factors which depend largely on the proportions of sulphide in the charge4 ,the gas for the acid plant must be supplied in regular and continuous amount1 at a specific temperature1 and this calls for special care in the smelting operation1 furnace manipulation and blast supply1 supplementary air admission1 etc4 ,about #ce to #d per cent4 of ,,so#b in the gases delivered at the chambers is the minimum proportion for satisfactory working2 ,,co#b should not exceed about #e per cent41 and about #fj per cent4 or more of oxygen is also necessary4 7b7 ,in addition to the capital charges involved in the acid-making installation and the costs of adapting the furnace plant and operations to the process1 the problem of putting the acid upon the market on a satisfactory economic basis is important1 particularly in view of the competition from other sources4 ,the districts which offer a consuming area for the large and regular supply of acid from the smelters are not unlimited in number1 and are probably readily accessible to other sources4 ,in view of the costs of production1 the distance of the smelter from the market is a serious consideration1 since freight charges on sulphuric acid are high1 involving special regulations with respect to the form of car and conditions of traffic1 and they may readily exceed all possible profits resulting from the sale of the product4 ,in ,tennessee the companies were forced to install acid plants4 ,that at ,copperhill is the largest in the world2 commenced in #aijf1 acid manufacture began about two years later1 after much experimenting1 and further units have gradually been added4 ,the plant now includes two ,glover towers1 #cj feet across and #ej feet high1 #fd cooling chambers about #aa feet #aa feet #gj feet high1 eight cooling chambers #aa feet #bd feet #gj feet high1 twelve old chambers #ej feet #ej feet #gj feet1 six new chambers #ej feet #ej feet #ge feet1 eight new chambers #bc feet #ej feet #hj feet1 eight ,gay-,lussac towers1 with complementary tanks1 etc4--producing at the rate of #afh1jjj tons of #fj ,b4 acid per annum4 ,the ,ducktown ,company's plant was installed in record time1 and1 like the ,copperhill plant1 comprises elaborate dust chambers and flues1 with ,glover and ,gay-,lussac towers of special design and construction1 and enormous acid-making chambers with complex valves and fittings4 ,the plant is designed to produce about #afj tons of #fj ,b4 acid daily4 ,the analysis of the gases supplied to the towers varied during the early working of the plant2 under fairly normal conditions the average analysis of the gases delivered is ,,so#b #ce per cent41 ,,co#b #ce per cent41 ,,so#c trace2 the oxygen in the mixture being about #hj per cent4 ,the temperature is also apt to vary4 ,full details on these points are not yet available for general service4 ,the management of both companies have been successful in obtaining particularly satisfactory contracts for the purchase of their acid by fertiliser corporations4 ,references4 ,peters1 ,e4 ,d41 8,principles0 and 8,practice of ,copper ,smelting40 ,blast-furnace ,manipulation4 ,shelby1 ,geo4 ,f41 8,alumina in ,blast-,furnace ,slags40 ,eng4 and ,min4 ,journ41 #aijh4 ,offerhaus1 ,c41 8,copper ,blast-,furnace ,smelting at ,anaconda40 ,eng4 and ,min4 ,journ41 #aijh1 ,aug4 #g1 pp4 #bdc-bej4 ,sackett1 ,b4 ,l41 8,the ,granby ,smelter ,equipment40 ,mines and ,minerals1 #aiaj1 ,april1 p4 #ebd4 8,operations of the ,tennessee ,copper ,company40 ,official ,annual ,reports of the ,general ,manage4r ,walker1 ,a4 ,l41 8,the ,metallurgy of ,copper in #aiaj40 ,eng4 and ,min4 ,journ41 #aiaa1 ,jan4 #g1 p4 #ci4 ,austin1 ,l4 ,s41 8,review of ,metallurgy in #aiaj40 ,met4 and ,chem4 ,ind41 #aiaa1 ,jan4 #aa1 p4 #dj4 ,rice1 ,claude ,t41 8,handling ,copper ,smelting ,gases40 ,eng4 and ,min4 ,journ41 #aiaa1 ,mar4 #be1 p4 #fad4 8,cottrell's ,fume ,smelter40 ,min4 and ,scient4 ,press1 ,aug4 #bf1 ,sept4 #b1 #aiaa4 ,herrick1 ,r4 ,l41 8,boston and ,montana ,co4's ,smelter at ,great ,falls40 ,mines and ,minerals1 #aiji1 ,dec41 p4 #beg4 ,harvard1 ,f4 ,t41 8,condensation of ,fume and ,neutralisation of ,furnace ,gases40 ,bull4 ,amer4 ,inst4 ,min4 ,eng41 ,no4 #dd1 #aiaj1 ,aug4 8,mineral ,industry40 ,annual4 ,pyritic ,smelting4 ,holway1 ,john1 8,a new ,application of ,bessemer's ,method of ,rapid ,oxidation1 by which ,sulphides are utilised for ,fuel40 ,journ4 ,society of ,arts1 ,feb4 #ahgi4 ,rickard1 ,t4 ,a41 8,pyrite ,smelting40 ,sticht1 ,robert1 8,ueber das ,wesens des ,pyrites ,verfahrens40 ,metallurgie1 ,nov4 #bb1 ,dec4 #h1 #aijf4 ,wintle and ,alabaster1 8,pyritic ,smelting40 ,trans4 ,inst4 ,min4 and ,met41 #aijf1 vol4 xv41 p4 #bfi4 ,nicholls1 ,f4 ,s41 8,pyrite ,smelting in ,tilt ,cove1 ,newfoundland40 ,eng4 and ,min4 ,journ41 #aijh1 ,sept4 #e1 p4 #dfb4 ,wright1 ,l4 ,t41 #dd 8,pyritic ,smelting without ,coke40 ,min4 and ,scient4 ,press1 #aijf1 ,sept4 #bi4 ,sulphuric ,acid ,manufacture4 ,falding1 ,f4 ,j41 and ,channing1 ,j4 ,p41 8,pyrite ,smelting and ,sulphuric ,acid ,manufacture40 ,eng4 and ,min4 ,journ41 #aiaj1 ,sept4 #ag1 p4 #eee4 ,freeland1 ,w4 ,h41 and ,renwick1 ,c4 ,w41 8,smeltery ,smoke as a ,source of ,sulphuric ,acid40 ,eng4 and ,min4 ,journ41 #aiaj1 ,may #bh1 p4 #aaaf4 ,,lecture ,,viii4 ,,the ,,bessemerising ,,of ,,copper ,,mattes4 ,development of the ,process -- ,the ,converter -- ,converter ,linings -- ,grade of ,matte -- ,operation of the ,process -- ,systems of ,working4 ,in modern copper smelting practice1 matte of 8converter grade10 containing from #cj to #ej per cent4 of copper1 is bessemerised for the production of metallic copper4 ,successful practice depends upon a regular and continuous output of matte from the furnace plant being available1 and upon a capitalisation and resources on a sufficiently large scale for continuous operation of the whole of the smelting plant4 ,development of the ,process for ,bessemerising ,copper ,mattes4--,the success of ,bessemer's process1 which was applied in #ahef to the production of steel by blowing air through molten cast-iron1 led to a suggestion for its application to copper mattes and to some experiments on the subject by ,semenikow1 a ,russian engineer1 ten years later4 ,it was not until #ahgh that any further work was conducted on a practical scale4 ,in that year ,john ,holway suggested and worked out the scheme already referred to1 the principles of which as outlined by him1 form the foundation of the pyritic and converter practice of the present time4 ,air was blown through heated ,rio ,tinto pyrites in an ordinary ,bessemer steel converter and the experiments met with considerable success4 ,the apparatus was1 however1 not deemed convenient1 as the process worked very intermittently and large quantities of slag were produced which required to be poured off at intervals1 whilst the position of the tuyeres in this form of converter was found to be unsatisfactory4 ,there are many practical difficulties in employing the same kind of apparatus for the converting of copper mattes as for the bessemerising of cast-iron into steel4 ,in the first instance1 the final steel product differs but little in weight or bulk from the original charge1 whilst the process produces but little slag1 owing to the comparatively small proportions of silicon and manganese which require to be oxidised--whereas in copper converting1 the quantity of slag produced is almost equal in weight to the amount of matte originally charged1 whilst the resulting copper product amounts to less than one-half of this weight4 ,further1 in bessemerising cast-iron1 the blow is of very short duration2 in copper matte converting1 it occupies more than two hours1 and the relative heat losses are1 in consequence1 markedly different4 ,finally1 the lining of the steel converter chiefly serves to protect the shell2 its function in the copper converter was to act also as flux for the iron oxides produced on blowing4 ,in ,holway's final form of apparatus for the pyritic smelting of copper ore to metal1 the introduction of siliceous material as a flux for the iron oxide and the use of basic lining were arranged for1 with the object of overcoming the difficulties caused by the corrosion of the siliceous lining which acted as flux4 ,though several years elapsed before the pyritic treatment of ore was successfully conducted1 the process of bessemerising the fluid matte to metal was successfully applied on a commercial scale by ,manhs in #ahhj1 although it was not until the following year that ,david's device of placing the tuyeres horizontally and at such a height above the bottom as not to interfere with the metal which is obtained1 solved the final difficulties of operation on a practical scale4 ,in #ahhc-d the ,manhs converter was introduced into the ,united ,states1 and at about the same time the barrel form was designed by ,manhs and ,david1 and was also readily adopted4 ,both forms developed in size1 increasing in capacity from #a ton to that of #g to #aj tons4 ,until comparatively recent years1 the chief modifications in practice were concerned with operating and constructional details rather than with radical changes in the principles of work4 ,experiments and research have meanwhile been in constant progress with the object of overcoming several of the grave defects connected with the apparent necessity for the destruction of the siliceous converter-lining by using it as flux1 which was due to the difficulties of causing the iron oxide to flux with silica when introduced in any other way4 ,the most vital improvement introduced into converting practice1 and that with which the future developments are most closely bound1 is the successful adaptation of basic material for the purpose of lining the converter4 ,this achievement1 together with recent success in the introducing of siliceous flux1 promises to solve many of the difficulties connected with the bessemerising of low-grade matte by a continuous process4 ,suggested by ,holway1 basic linings were tried at the ,parrott ,smelter1 ,butte1 in #ahij1 by ,keller and others1 but under the conditions of working at that time they were found to be unsuccessful when operated on an industrial scale4 ,valuable pioneer work was undertaken by ,baggaley in ,montana1 and after many trials1 his method was successfully operated for some months at the ,pittsmont ,smelter under ,heywood's direction in #aijf4 ,visits of inspection to this smelter in #aijh proved disappointing1 it being found that most of the plant which had promised the solution of such difficult problems had been dismantled1 largely owing to economic difficulties connected with its operation1 and the works were in process of re-organisation for the older system of working4 ,meanwhile1 since #aijc1 ,knudsen1 at ,sulijtelma1 ,norway1 has successfully employed a small basic-lined converting furnace for the combined pyritic smelting and converting of heavy sulphide ores4 ,the process consists usually of pyritic liquation of the sulphides1 followed by a further concentration of the matte up to ordinary converter grade by bessemerising1 the higher grade matte being then transferred to a silica-lined vessel and blown to metal in the usual way4 ,the successful operating of the basic-lined converter on the large scale and under the conditions of working at great modern plants was first established by ,smith and ,pierce at the ,baltimore ,copper ,company's ,smelter1 and the method has since been installed and worked with success at ,garfield1 ,utah 7five converters in operation1 one in reserve72 at ,perth ,amboy1 ,n4,j42 at the ,washoe ,smelter at ,anaconda--where the whole plant is being adapted for basic-converting--and at several other works4 ,a recent and promising development has been the reported successful blowing of fine siliceous concentrates through the tuyeres of converters at the ,garfield ,smelter1 a method by which it might be possible to effect the rapid and efficient extraction of values from fine material otherwise difficult to deal with1 affording at the same time a means of conveniently supplying siliceous flux in a manner possessing many advantages4 ,principles of the ,bessemerising ,process4--,the principles underlying the converter process are those which form the basis of pyritic smelting practice--of which bessemerising is but a phase4 ,the reactions involve the very rapid oxidation of iron and sulphur under practically ideal conditions1 and the fluxing by silica of the iron oxide so produced4 ,the heat of oxidation keeps the materials in a thoroughly molten state1 and maintains the temperature well above that required for slag formation and perfect fluidity4 ,the heat derived by the combination of oxygen with the iron and sulphur and that of the iron oxide with silica is developed so rapidly and in such quantity1 owing to the large masses now worked with1 as to cause a reaction-activity sufficient to make the process independent of heat from external sources4 ,it will be noted how markedly the more recent developments of copper smelting have taken advantage of the factors of the time element and mass influence in obtaining enormous heat intensities and consequent high temperatures1 by conducting oxidation of sulphides as rapidly and in as large mass as possible4 ,the same absolute quantities of heat per unit weight of charge were liberated in the older smelting methods involving roasting1 but the more leisurely manner of operating allowed the dissipation and dispersion of much of this heat1 thus necessitating the employment of supplementary carbonaceous fuel4 ,the ,converter4--,the converter is a lined steel vessel in which the molten matte is contained1 and which allows of air being blown through the material by means of tuyeres which pass through the walls4 ,the early form of converter was bottom-blown1 and similar to that invented by ,bessemer1 but it was not successful in operation on the small quantities of copper matte worked with1 owing to the chilling effect of the cold air on the copper1 which1 when produced1 sank to the bottom and set above the tuyeres1 stopping the air blast1 and causing much loss of metal in the slag4 ,the later form of converter was barrel-shaped1 with a horizontal row of tuyeres situated at some distance above the bottom so as to allow the copper to settle1 protected from the action of the blast1 and also to allow of the punching of the tuyeres as required4 ,the modern forms of converter comprise both the vertical and the barrel types1 modified largely as regards size and constructional details1 and although the vertical form is still in use and is even preferred at several smelters1 it has been largely superseded at most plants by the barrel-shaped variety1 whilst the possibilities of greatly enlarged vessels using basic linings are likely to favour this replacement still further4 #a4 ,the ,upright ,bessemer ,vessel is used1 and found satisfactory at ,great ,falls and at ,mt4 ,lyell4 ,the general size has been #h feet diameter and #af feet height1 with a capacity ranging from #e to #ab tons1 according to the condition of the lining1 though at ,great ,falls converters of #ab feet diameter with corresponding capacity are now in use4 ,the advantages of the vertical form are1 that1 owing to the greater depth of matte through which the air passes1 the oxidation is more rapidly conducted1 the lining is more efficiently supported1 and the wear by abrasion upon the lining is found to be considerably less in amount and to be more uniformly distributed4 ,on the other hand1 the greater depth of matte necessitates a greater blowing pressure in order to force the air through the material1 whilst control over the operations becomes a matter of greater difficulty4 ,illustration3 ,fig4 #fb4-,sectional ,elevation and ,plan of ,barrel-,shaped ,silica-,lined ,converter 7,peters74 #b4 ,the ,barrel ,form of ,converter is the type in common use4 ,among the advantages claimed for this form are those which accrue from being able to operate the same weight of matte in more shallow layers1 as compared with the upright form--thus requiring lower blast pressures4 ,another advantage is the greater ease of regulating the depth of material blown through1 by tilting the converter and thus altering the relative position of the tuyeres4 ,owing to the successful adoption of the basic lining1 the barrel type of converter has now to be divided into two classes1 since the basic converter differs from the silica-lined type in constructional details1 and is usually of much larger dimensions4 ,its operation is also conducted on somewhat different lines4 ,illustration3 ,fig4 #fc4--,latest ,form of ,silica-,lined ,barrel ,converter4 7a7 ,the silica-lined barrel converter varies somewhat in size1 the ,anaconda converters were1 however1 representative of the most convenient dimensions4 ,the shell consists of -inch boiler plate1 #h feet in diameter1 and #ab feet #f inches long4 ,the converter is constructed in two portions1 the body and the hood1 in order to facilitate removal1 relining1 and general repairs4 ,the ends are lined with #i inches of firebrick1 and the body with #d inches2 it is then rammed with lining material to a thickness of about #ah inches in all parts4 ,there are #af #a-;inch tuyeres placed horizontally1 and in the latest forms of converter1 the air is supplied by individual tuyeres which are connected to the blast box1 and which are provided with ball-valves to prevent leakages and back-running during the necessary punching4 ,the cavity is about #h feet #d feet by #f feet deep when first made1 and the converter then holds conveniently about #g tons of matte4 ,the weight of lining is about #af tons1 and it lasts six to nine blows4 ,the blast-pressure used is #af lbs4 per square inch4 ,the hood is bolted on to the body1 and is furnished with conical safety-pieces to give notice of the wearing through of the lining4 ,the converters tilt upon rails1 which are strapped round the body1 and which travel upon rollers4 ,motion is communicated to the converter either by connection with an electrical drive1 or very often by hydraulic power connecting through a rack to a pinion attached to one of the trunnions4 ,the air supply is usually from piston-driven blowing engines1 communicating through a blast pipe to the hollow supporting trunnion of the converter1 from which the air passes to the blast box4 ,illustration3 ,fig4 #fd4--,longitudinal ,section of ,basic-,lined ,converter4 7b7 ,the ,basic-lined ,converter4--,the adoption of basic linings is of such recent date that although the present form appears to have given satisfaction1 later developments in basic practice may cause further modifications in design4 ,r4 ,h4 ,vail gives the following details3-- ,as at present operated1 the basic-lined converters are long barrel-shaped vessels consisting of a -inch steel shell1 #bc feet long and #aj feet in diameter1 lined with magnesite materials so as to leave a cavity about #bj feet #g feet #f feet4 ,air is supplied from thirty-two #a-;inch tuyeres1 each separately connected with the blast box and controlled by a valve4 ,provision has to be made for the marked expansion of the basic lining-material by leaving the top of the steel shell open1 joining-up the free ends by tie-rods 7#ac1 ,fig4 #fe71 whilst the tuyere-pipe connections are flexible4 ,the main opening or throat1 for the charging of matte and flux1 is situated in the arch at one end of the converter2 it is #dj inches in diameter1 and surmounted by a short chimney-cap of iron1 which is #cj inches high and lined inside with clay4 ,the vessel is charged through this opening4 ,metal and slag are poured from the converter through an opening in the side opposite the tuyeres1 which is kept closed by bricks during the operations4 ,an oil-burner is provided at one end1 for the purpose of supplying such extra heat as might be required1 in consequence of undue cooling of the copper towards the end of the blow or for heating up the lining after repairs4 ,the converter is supported as in acid practice1 though a tilting device employing wire ropes attached to hydraulic plungers is now being introduced in place of the rack and pinion method4 ,illustration3 ,fig4 #fe4--;,basic-,lined ,converter1 indicating ,tuyeres1 ,lining1 etc4 ,converter ,linings4--,the question of the lining has been the most important consideration in copper matte converting-practice4 ,the functions proper of the lining material are-- 7#a7 ,to preserve the steel shell and form a permanent receptacle for the molten materials2 by reason of its refractory character4 7#b7 ,to prevent undue losses of heat from the materials2 by reason of its low conducting power4 ,the employment of the lining material as a provider of suitable siliceous flux for the iron oxide1 though until recently of vital importance for the practical operation of the bessemerising process1 has been a necessary evil in many cases1 and although it might have been a source of considerable profit under certain conditions1 this function is unlikely in the future to be the consideration of greatest moment4 ,the vital requirements in modern converter practice are permanence of the lining and efficient means of effecting the fluxing of the iron oxide produced in the converting operation4 ,the necessity for the frequent relining of converters involves not only heavy direct expenses1 but it occasions waste of heat in the old linings1 waste of material1 loss of time1 interruption of the processes1 liabilities to outbreaks from the converters1 and necessitates much heavy machinery for the conveying of vessels for relining1 as well as large capital outlay in relining shops1 plant1 and appliances4 ,in consequence1 the employment of siliceous lining material as flux is usually a most expensive method of supplying the requisite silica2 and so much is this the case1 that an arbitrary limit to the iron contents of the matte has been rendered necessary1 in order to prevent too much of the lining material being used up at a single blow4 ,it was found cheaper to use other means of concentrating low-grade matte to a suitable grade for bessemerising--i4e41 to flux off the excess of iron by means of silica in the blast-or the reverberatory-furnace processes4 ,siliceous ,linings4--,until recently1 the only method for fluxing the iron in bessemerising1 found practicable on a commercial scale1 has been by the destruction of the siliceous lining1 minimising the dead losses as much as possible by employing for the purpose siliceous materials from which values in the form of gold1 silver1 or copper could be simultaneously extracted and collected in the products of the operation4 ,numerous attempts were made to effect combination of the iron oxides with silica introduced by some other method1 but none met with success4 ,manhs blew sand through the tuyeres1 and obtained as result a spongy unfused mass in the converter--whilst silica introduced in the form of lumps rose to the surface unchanged4 ,in each case what silica was required for flux1 was taken up from the siliceous lining4 ,experiments of a similar nature1 in which basic linings were worked with1 resulted in the fluxing silica being unabsorbed as before1 whilst the iron which was in process of oxidation1 not finding a suitable flux1 became super-oxidised1 resulting in the production of very infusible masses of magnetic or ferric oxides which rendered the process unworkable4 ,baggaley and others in ,montana devoted much attention to experiments on different methods for introducing silica which would flux successfully1 methods such as superheating or introducing silica held in suspension in fused silicates being tried1 but without marked success1 and for many years siliceous linings were necessarily worked with4 ,owing to the large quantities consumed1 the siliceous material must be obtainable cheaply and in abundant quantities4 ,it should be high in free silica contents1 since this constituent alone is effective as flux2 it should have the property of binding well with clay or other material1 so as to yield a rigid and impervious lining2 and most important of all from the economic standpoint1 it should carry values1 since by this means only1 could its destruction become an actual source of profit4 ,at first barren quartz and barren clay were largely used for linings1 but practice gradually developed in the direction of employing more profitable materials1 and especially those from which the extraction of the values might present difficulties1 in treatment by ordinary smelting methods4 ,the practice as followed until recently at ,anaconda is typical of such progress4 ,until #aijh the lining was chiefly made from highly siliceous ore obtained from ,snowstorm1 ,idaho1 carrying #hj to #he per cent4 of ,si,o#b1 #d per cent4 copper1 as well as gold and silver1 and a little iron and sulphur4 ,this ore was crushed in mills and mixed with sufficient slime from the slime ponds of the concentrating plant to make a binding mixture4 ,the slime1 which carries about #fj per cent4 of silica and also #be per cent4 of copper has excellent binding properties1 owing to its clayey consistency4 ,the proportions employed were #c of siliceous rock to #a of slime--no water was used1 the mixture being almost dry to the touch4 ,since ,may1 #aiji1 instead of employing ore obtained from outside sources1 siliceous second-class ,butte ore1 which was formerly concentrated1 has been very largely incorporated in the mixture used as lining material1 it contains #fe per cent4 silica1 about #ce per cent4 copper1 a little gold and silver1 and also iron and sulphur4 ,the lining mixture consisted of #bi parts of this material with #a part of slime4 ,it was thought at first that owing to the greater proportion of sulphides and the lower silica content of the ,butte ore1 this lining mixture might prove inefficient compared with the former material1 but with somewhat greater care in lining1 it was found that very little more ore was required1 and that tested by comparative silica contents it was more effective4 ,thus1 where the former linings lasted for an average of six #g-ton charges1 equal to #bj tons of copper per lining1 the new ones last #e such charges1 equivalent to #ag tons of copper per lining1 showing that although the efficiency per lining was reduced to #ij per cent41 yet1 calculated on comparative silica content1 the new lining proved to be the more efficient4 ,the operation of lining is conducted with much care2 the old lining is knocked away where necessary1 rods are placed through the tuyere holes1 and lining mixture is dumped in2 #f-;inch layers of material at a time being stamped down hard by means of an ,ingersoll-,sargent tamping machine1 until the lining reaches within #f inches of the tuyeres4 ,the wooden mould for the cavity1 made up of a number of jointed pieces1 is then placed in position1 and the ramming of layer after layer round the sides is continued as before4 ,the hood1 inverted1 is lined in a similar manner1 it is then placed in position on the converter body and bolted down1 a joint being made of moistened lining material4 ,the whole operation takes about #a hours4 ,the converter is then slowly dried by a wood fire1 coal being subsequently added and kept burning under the action of a low blast for five or six hours2 it is conveyed to the stand when required1 dropped into position on the trunnion bearings1 and the connections and adjustments very readily made4 ,the manipulation of relining at the ,tennessee smelter is conducted in a very similar manner4 ,basic ,linings4--,the all-important feature of the basic lining is its permanence1 which1 rendering the frequent relining of the converter unnecessary1 allows of many economies in connection with capital outlay on plant and in operating costs4 ,further1 owing to the lessened need for lining repairs1 the frequent hauling of converters to the repair-shops situated at the further end of the buildings is avoided4 ,this allows the employment of much larger converter units1 with obvious attendant advantages1 whilst it increases the ultimate possibility of continuous operation4 ,thus1 the size at present employed1 though the process has been in operation but a short time1 is #bf feet by #ab feet1 with a capacity of #ce to #de tons of matte1 and a daily output of #cc tons of copper from #dj per cent4 matte4 ,such a converter1 lined with #i inches of basic material1 will operate for #b1jjj to #c1jjj tons of copper before requiring repairs4 ,keller's report on basic linings in #ahij stated that they could not be employed successfully1 because 7a7 basic material1 being a good conductor1 caused the outside of the converter to become too hot and the inside too cold2 7b7 such material broke up easily and so was unsuitable for use in permanent linings2 and 7c7 even when basic linings were employed1 the silica which was added as flux1 refused to combine with the iron oxides4 ,these views were very generally accepted for some years1 until ,baggaley's persistent efforts and finally those of ,pierce and ,smith showed that by perfecting the constructional methods and details1 by preventing heat losses as much as possible1 and by operating on very large masses of hot material1 the above difficulties could all be overcome and the basic lining successfully employed4 ,the lining is of magnesia brick1 and is #i inches in thickness1 except at the tuyeres1 where the bricks are #ah inches thick4 ,in the bottom of the converter and extending to within #ah inches of the tuyere level is placed a filling of ordinary firebrick1 which is #ac inches thick in the middle and #d inches thick at the sides4 ,the magnesite bricks are laid in dry magnesite powder1 except near the tuyeres1 where a mixture of magnesia and linseed oil is used4 ,expansion cushions of wood are inserted at intervals along the side of the fresh linings which are then 8seasoned0 with molten copper4 ,the required quantity of siliceous flux1 as calculated1 is now successfully introduced by dumping it into the converter1 and pouring the matte charge upon it4 ,the ,grade of ,matte for ,converting4--,the grade of matte which is economically the most profitable to treat in the converter is a factor of great importance1 since1 if limits be fixed1 the preliminary smelting stages for matte production are made less flexible1 whilst in order to obtain matte of the correct grade1 the smelting operations may require to be conducted at greater cost1 or else additional smeltings for further concentration of the first matte may be necessitated--as is the case1 for instance1 in pyritic smelting at present4 ,the grade of a matte is usually expressed in percentages of copper1 but from the standpoint of the practical converter operations1 the proportion of iron is the factor which decides the suitability or otherwise of the matte for treatment1 and since mattes may be regarded as mixed sulphides of iron and copper1 a matte rich in copper is correspondingly low in iron contents1 whilst a low-grade matte is high in iron4 ,the importance of the iron contents of the matte from the viewpoint of converter practice is due to iron being the chief source of heat in the operations1 and to the fact that the iron oxide produced from it is the constituent which requires a supply of flux in order that the reactions may proceed and the process be successfully operated4 ,the economic limit to the grade of matte suitable for the converter process is reached when it becomes less costly and more profitable to supply the required siliceous flux for the iron in the ordinary smelting furnace rather than in the converter4 ,so long as the destruction of the lining was practically the only medium by which silica could be efficiently supplied1 the limit to the iron contents of the matte was fairly rigid4 ,the bessemerising of a low-grade matte 7low in copper contents1 high in iron7 entails the great advantage that a high temperature is obtained1 owing to the fuel-value of the iron4 ,on the other hand1 however1 grave disadvantages attend such practice1 especially when working with the comparatively small quantities of material usually operated1 and when employing siliceous linings4 ,these disadvantages include the factors that-- 7a7 ,large quantities of iron oxide are formed1 which require siliceous flux4 7b7 ,large quantities of highly ferruginous slag are produced which carry copper values1 and which also demand special attention in operating4 7c7 ,the quantity of copper obtained is comparatively small1 thus increasing the proportionate losses and working difficulties4 ,in bessemerising a high-grade matte1 the heat production is much smaller1 owing to the decrease in the quantity of iron1 which is the chief fuel of the process1 and the limiting grade is quickly reached above which the bessemerising operation upon the matte ceases to be self-supporting4 ,in consequence1 up to a comparatively recent date1 a compromise has necessarily been effected1 and the grade of matte operated upon has been such as to cause as much heat production as possible1 together with the smallest practicable amount of fluxing action4 ,on these grounds1 a matte containing from #dj to #ej per cent4 of copper 7equivalent to #cb to #bb per cent4 of iron7 has been found generally the most suitable4 ,at several smelters1 lower-grade mattes of from #cb to #dj per cent4 copper-contents are converted most profitably1 owing to such special circumstances as the profits resulting from the destruction of lining material1 or in consequence of the fact that greater operating costs would be involved in concentrating the matte to a higher grade by the ordinary furnace-smelting methods4 ,in this connection1 the successful adaptation of the basic lining by permitting the supplying of flux by means other than from the linings1 has very important application and possibilities4 ,owing to the frequent relining of these converters being then no longer necessary1 mechanical difficulties of conveying the converter bodies to the relining shops are lessened1 and larger converter units can now be employed1 treating1 even at the present stage of development1 between six and seven times as large an amount of matte as formerly4 ,by operating on such big charges1 pouring off slag as produced1 and adding fresh matte and flux without fear of destroying the lining1 the difficulties attending the converting of low grade mattes have been successfully overcome4 ,the limit to the grade of matte economically suitable for the process will depend1 in the future1 chiefly upon the comparative costs of effecting the required concentration up to any desired grade1 in the blast-or reverberatory-furnace1 or in the converter4 ,the modern smelting scheme appears1 therefore1 likely to develop into the preliminary smelting of the ores by the cheapest method available1 for matte of a grade best suited economically to the running of the furnace1 the grade being independent of any rigid limit for the subsequent converting operations--the matte being then bessemerised as usual4 ,the ,converting ,process--,acid ,lining4--,there are two main stages in the converting of copper mattes4 ,the first is essentially elimination of iron sulphide2 the second1 elimination of the remaining sulphur4 ,the product of the first main stage is a white metal1 practically pure copper sulphide1 the iron of the matte having been slagged off in the form of silicate1 and the corresponding sulphur eliminated as ,,so#b4 ,the reactions during this stage are well known3 the oxygen of the air blown in1 yields oxides of iron and of sulphur1 as well as some copper oxide4 ,the latter1 immediately reacting with iron sulphide which still remains1 re-forms copper sulphide1 with the production of more iron oxide4 ,the iron oxides are fluxed by the siliceous materials present1 forming ferrous silicate slags4 ,the iron oxidation is productive of the greater part of the heat in the operation1 and high temperature usually marks this stage of the process1 which may be termed 8the slagging stage40 ,the flame which issues from the converter during this period is usually characterised by a green colour1 caused apparently by the formation of iron-silicate slag4 ,when this stage is completed and the slag poured off1 the white metal is blown up to blister copper--this constituting the second main stage of the process4 ,the chief reactions are those of sulphur elimination and the production of metallic copper1 caused by the action of some of the copper oxide first produced1 upon the copper sulphide still present4 ,the flame during this period is small1 thin1 and fairly non-luminous1 usually of a red-purple to bronze purple colour4#af ,the progress of the blowing from copper matte to white metal and thence to blister copper is usually indicated and controlled at the smelter by the appearance of the flame which issues from the nose of the converter during the first periods1 and by the character of emitted shots during the later stages4 ,this is particularly the case with mattes of moderate purity worked in the silica-lined converter4 ,the successive changes in these indications are gradual1 but are easily followed by the experienced skimmer1 who is thus able to judge readily as to the manner in which the blow is progressing1 and also as to the temperature1 composition1 and nature of the metal in the converter4 ,,table ,,xii4--,,changes ,,in ,,composition ,,during ,,bessemerising4 ,time4 ,composition4 ,hrs,mins ,cu4 ,au4 ,ag4 ,oz4 ,oz4 #aa4eb am ,charged ,no4 #a blast matte144 44 #dfjhjae #caej #aa4ed am ,blow commenced4 #ab4jd pm ,sample ,no4 #a blowing1 44 #aj #dfjbjag #cahj #ab4ad pm ,sample ,no4 #b blowing1 44 #bj #eadfjah #cehj #ab4ah pm ,punched #c minutes4 #ab4bd pm ,sample ,no4 #c blowing1 44 #cj #ecbgjbj #cghj #ab4be pm ,punched #g minutes4 #ab4cd pm ,sample ,no4 #d blowing1 44 #dj #efbijba #djhj #ab4dj pm ,punched #b minutes4 #ab4dd pm ,sample ,no4 #e blowing1 44 #ej #eiijjbb #dcgj #ab4de pm ,punched #b minutes4 #ab4ed pm ,sample ,no4 #f blowing1 #a #jj #fbfgjbc #ddij #ab4ee pm ,punched #f minutes4 #a4jd pm ,sample ,no4 #g blowing1 #a #aj #fghijbe #dibj #a4jg pm ,punched #c minutes4 #a4ab pm ,blow stopped4 #a4ac pm ,skimmed4 #a4ad pm ,blow resumed4 #a4ad pm ,sample ,no4 #h blowing1 #a #bj #gcigjbg #edij #a4ag pm ,punched #b minutes4 #a4ba pm ,blow stopped4 #a4bb pm ,skimmed4 #a4be pm ,blow resumed4 #a4be pm ,sample ,no4 #i blowing1 #a #cj #gghbjbh #egcj #a4cd pm ,sample ,no4 #aj blowing1 #a #dj #gdafjbf #edcj #a4dd pm ,sample ,no4 #aa blowing1 #a #ej #hagbjae #egfj #a4ed pm ,sample ,no4 #ab blowing1 #b #jj #ihejjghajggj #b4jb pm ,punched #a minute4 #b4jd pm ,sample ,no4 #ac blowing1 #b #aj #ih4egjdj #ha4fj #b4je pm ,punched #b minutes4 #b4jh pm ,blow stopped1 test for ,cu4 #b4ji pm ,blow resumed4 #b4aj pm ,blow finished4 ,converted copper1 #b #af #ii4jhjch #hchj ,total time punching1 44 #bh 44 44 44 ,total time of blow1 #b #af 44 44 44 ,actual time of blow1 #b #ji 44 44 44 ,time4 ,composition4 ,insol- ,hrs,mins uble ,fe4 ,s4 ,as4 #aa4eb am ,charged ,no4 #a blast matte144 44 #jae #bdcjbdgjjbb #aa4ed am ,blow commenced4 #ab4jd pm ,sample ,no4 #a blowing1 44 #aj #acj #bcgjbbiejjg #ab4ad pm ,sample ,no4 #b blowing1 44 #bj #jcj #bjejbcajjjf #ab4ah pm ,punched #c minutes4 #ab4bd pm ,sample ,no4 #c blowing1 44 #cj #aaj #ahgjbbaejjf #ab4be pm ,punched #g minutes4 #ab4cd pm ,sample ,no4 #d blowing1 44 #dj #acj #afbjbahejjf #ab4dj pm ,punched #b minutes4 #ab4dd pm ,sample ,no4 #e blowing1 44 #ej #jij #acgjbaiejjf #ab4de pm ,punched #b minutes4 #ab4ed pm ,sample ,no4 #f blowing1 #a #jj #acj #aadjbacejjf #ab4ee pm ,punched #f minutes4 #a4jd pm ,sample ,no4 #g blowing1 #a #aj #jfe #gfjbaaejje #a4jg pm ,punched #c minutes4 #a4ab pm ,blow stopped4 #a4ac pm ,skimmed4 #a4ad pm ,blow resumed4 #a4ad pm ,sample ,no4 #h blowing1 #a #bj #jbe #cdjbjajjje #a4ag pm ,punched #b minutes4 #a4ba pm ,blow stopped4 #a4bb pm ,skimmed4 #a4be pm ,blow resumed4 #a4be pm ,sample ,no4 #i blowing1 #a #cj #jae #jijaifjjjd #a4cd pm ,sample ,no4 #aj blowing1 #a #dj #ccj #bfjaffjjjd #a4dd pm ,sample ,no4 #aa blowing1 #a #ej #jbe #jbjaecejjd #a4ed pm ,sample ,no4 #ab blowing1 #b #jj #jjagtrace #jghjjej #b4jb pm ,punched #a minute4 #b4jd pm ,sample ,no4 #ac blowing1 #b #aj #jjeb #jja #jghjjcc #b4je pm ,punched #b minutes4 #b4jh pm ,blow stopped1 test for ,cu4 #b4ji pm ,blow resumed4 #b4aj pm ,blow finished4 ,converted copper1 #b #af #jjagtrace #jjajjcc ,total time punching1 44 #bh 44 44 44 44 ,total time of blow1 #b #af 44 44 44 44 ,actual time of blow1 #b #ji 44 44 44 44 ,samples taken each #aj minutes from beginning of blow until finished4 ,in general character1 this colour sequence1 during the bessemerising of the ordinary class of copper mattes--i4e41 those consisting largely of iron1 copper1 and sulphur1 with but moderate quantities of impurity--does not vary very markedly1 but the body and luminosity of the flame depend to a great extent on the nature of the charge and on the working conditions4 ,the colours are intensified by very hot metal1 large charges1 heavy blast1 and rapid working1 and particularly by the presence of secondary constituents1 such as zinc1 lead1 or arsenic1 which liberate dense white fumes1 and so increase the luminosity of the flame4 ,there are generally four main variations in the appearance of the flame from the acid-lined converter3-- ,oxidation of secondary ,dark reddish-brown ,at commencement constituents1 flame4 of blow1 ,burning of iron1 sulphur1 ,accompanied by much and coal1 smoke4 ,slagging stage1 ,iron-sulphide oxidation1 ,apple-green flame4 ,white metal stage1 ,copper oxidation in ,white-blue flame4 presence of slag1 ,blowing to blister ,sulphur oxidation1 ,thin red-purple flame4 copper1 ,the changes in composition of the charge during a converter blow have been traced by ,mathewson1 who assayed samples during the various stages2 some of these results are indicated in ,table xii4 and in ,fig4 #ff4 ,for full record see ,trans4 ,amer4 ,inst4 ,min4 ,engineers1 #aijg4 ,in general1 of the constituents present in the matte1 iron and sulphur are removed very readily1 #if per cent4 of the former and #ec per cent4 of the latter in the slagging stage of the blow1 whilst the elimination of the injurious impurities is high1 bismuth and arsenic being removed to the extent of upwards of #ij per cent41 and of the antimony1 selenium1 and tellurium1 from #dj to #gj per cent4 are eliminated 7see p4 #bag74 ,working of a ,typical ,charge in ,silica-lined ,converter4--,the ,anaconda converter plant is now being operated with basic linings4 ,the former practice at this works was representative of the best type of acid-lined working1 and the following description1 based upon this practice1 is typical of the method in general use4 ,there were in operation twelve converter stands of the dimensions previously given4 ,normal working was to convert the #de per cent4 copper matte to white metal1 to pour off slag1 blow to blister copper1 and pour the resulting metal--in regular sequence4 ,the colour-changes in the flame during bessemerising are indicated in the colour-photographs reproduced in the frontispiece4 ,illustration3 ,fig4 #ff4--;,composition of a ,charge during ,bessemerising ,operation4 ,illustration3 ,fig4 #fg4--,pouring ,slag1 ,anaconda4 ,seven to #h tons of matte at an average temperature of #ijj ,c4 are charged into the converter1 which is in an upright position with the blast on 7#af lbs4 per square inch74 ,the operation of charging occupies three minutes4 ,a few lumps of coal are thrown in1 a vigorous action commences1 copious and heavy white fumes and smoke and a full red to red-brown flame being emitted4 ,the converter is now turned slowly back1 so as to bring the tuyeres more completely under the charge and ensure more rapid and efficient oxidation1 and the blow proper then commences4 ,the flame drops for a time1 continuing to be of a red to red-purple colour for two to eight minutes1 after which1 green commences to show in the red smoky flame 7,a71 indicating that the first or slag-forming period of the blow is beginning4 ,the green colour becomes more prominent and continues for #dj to #de minutes 7,b74 ,a preliminary pouring off of slag is then usually made1 owing partly to the danger of violent or even explosive interaction which might otherwise occur between matte and slag1 and also with the object of keeping down the copper losses in the slag by removing the greater portion of the latter at as early a stage as possible4 ,the blowing is then continued4 ,flashes of blue now occasionally appear in the flame1 and gradually increase in number until the flame becomes blue-white 7,c71 which indicates that most of the iron has been slagged off and that the white metal stage is reached4 ,the blue-white colour of the flame is to be attributed to the production of copper silicate1 owing to the tendency of the copper oxide formed by the air blast at this stage1 to flux off1 and to produce the silicate rather than attack the copper sulphide4 ,this formation of copper-silicate is particularly liable to occur in the presence of much slag and at high temperatures1 factors which are well known to encourage this selective combination1 and which prevail at this stage4 ,the blowing up to white metal takes about one hour4 ,slag is then poured off again1 until an iron rabble held under the stream commences to show signs of 8metal0 which give an appearance of spots of grease on the blade4 ,the charge is then usually 8doped40 8,dope0 consists of highly cupriferous scrap1 cleanings1 slags1 residues1 also some siliceous material1 added partly for the purpose of cooling down the charge which tends to become overheated at this stage4 ,the converter is turned up again and the blowing is resumed in order to convert the white metal to blister copper4 ,the main reaction which now proceeds is represented by the equation ,cu#b,s #b;,cu#b,o #f;,cu ,,so#b4 ,this stage of the blow also occupies about one hour or more1 according to circumstances4 ,it commences with a vivid red flame accompanied by smoke1 but this soon dies out and a thin purple1 almost colourless1 flame results1 which continues practically unchanged for the remainder of the blow 7,d74 ,the temperature of the white metal is to some extent judged by the appearance of the flame1 a red-brown colour indicating the correct temperature4 ,if the colour be too red1 the metal is too cool1 and coal is thrown in2 if the tint be too orange1 the temperature is too high1 and dope is added4 ,constant punching of the tuyeres by long steel chisels is required during this stage of the blow1 owing to the lessened heat production due to diminution of iron1 and also to the marked tendency for the liberated copper to chill round the tuyeres4 ,the end of the blow is most difficult to judge1 and although the size and colour of the flame offer some criterion1 the usual and most important guide is the emission of small shots of copper which no longer stick to the hood situated above the converter throat1 but which rebound from it4 ,this is the stage where the skill and judgment of the skimmer are most tried4 ,when the blow is considered satisfactory1 the character of the metal is further tested by pouring a small quantity on to the floor--a rugged and uneven surface indicating satisfactory metal4 ,if poured too soon1 the copper is coarse and impure2 if poured too late1 heavy losses in the slag result1 owing to excessive oxidation of the metal4 ,the copper is then poured into a ladle1 and conveyed to the refining and casting furnaces4 ,the whole operation for a straight run occupies about two hours1 but the time required in general naturally depends upon the rapidity of working1 and particularly on the grade of matte1 and the volume and pressure of the blast4 ,the slags during the early part of the blow generally carry about #b per cent4 of copper1 after the white metal stage is passed1 they are usually much richer1 on account of the intensely oxidising atmosphere which prevails1 and the decreasing quantity of protecting sulphur4 ,these later slags often contain upwards of #bj per cent4 of copper1 and in consequence as much slag as possible is poured off during the early stages of the blow1 and the quantity towards the close is kept at a minimum4 ,the subsequent treatment of the converter slag depends very much upon the conditions of work at the smelter2 at ,anaconda1 the iron contents of this slag are very useful in the blast-furnace charge1 as there is a shortage of suitable basic flux for the silica of the rather siliceous charges4 ,the slag is poured from the converters into ladles1 and conveyed to a slag-casting machine1 consisting of a conveyor belt carrying cast-iron moulds which are sprayed with cold water1 the slag being thus cast into cakes suitable for the blast-furnace charge4 ,at ,tennessee1 the pyritic-smelting slags are already too ferruginous for any addition of irony converter-slags in the blast-furnace charge to be desirable1 and the only metallurgical treatment for which these are suited is that of recovering from them the large amount of copper which they carry4 ,the molten converter slag is1 therefore1 poured directly into the blast-furnace settlers1 and by this means1 the slags are cleaned and the values recovered4 ,at the new ,tooele ,smelter1 under ,mathewson's organisation1 the molten converter slags are poured directly into the reverberatory furnaces1 there being no blast-furnace or settler plant1 and the cleaning and settling are thus very satisfactorily conducted4 ,systems of ,working3 ,acid-lined ,converter4--,the 8normal0 system of working--i4e41 blowing a matte-charge first to white metal1 then to blister copper--is not always practicable nor economically the best practice1 and the system of operating the charges depends largely upon the working conditions1 which are subject to much variation at different smelters4 ,even at the same plant1 the procedure has to be varied according to the attendant circumstances4 ,conditions which may influence the system of working include3-- 7a7 ,grade of matte4 7b7 ,temperature of matte4 7c7 ,condition of converter lining4 7d7 ,rate of production of matte4 7e7 ,condition of affairs at the casting and refining furnaces4 ,as instances of the way in which some of these circumstances affect procedure1 the following examples may be quoted4 7a7 ,when working with matte of low grade1 especially in small quantities1 as formerly operated1 the loss of heat by radiation and by that carried away in the large quantity of slag produced1 is very considerable1 whilst towards the later part of the blow1 the amount of sulphide fuel diminishes to such an extent that the maintenance of the desired temperature is difficult4 ,the bulk of the final copper-product of the operation is very small and the metal is therefore liable to chill4 ,in such cases1 the system of 8doubling0 is useful4 ,this consists of blowing the matte to the white-metal stage1 pouring off the slag and adding a further charge of matte4 ,this1 on the resumption of blowing1 restores heat and yields a charge of white metal sufficient to maintain the required temperature for the last stage of the blow1 as well as affording a convenient yield of metallic copper4 7b7 i4 ,when working with a freshly-lined converter the charge is necessarily rather less than usual1 owing to the smaller size of the cavity1 and this results in a smaller yield of white metal1 which is also colder4 ,at the white-metal stage the slag is poured off1 and the cavity having now become larger1 owing to the fluxing action upon the lining1 a fresh charge of hot matte is added1 introducing fresh heat1 further enlarging the cavity1 and providing for a hot and plentiful supply of white metal for the blowing up to blister copper4 7c7 ii4 ,when the lining commences to wear thin1 the converter may be retained solely for the purpose of blowing successive charges of white metal up to blister-copper1 since owing to the very low iron content of white metal1 there is little fluxing action on the lining during this stage1 whilst the large quantity of white metal which can be operated in the enlarged cavity ensures a good supply of heat4 ,when linings burn through1 the charge is transferred to another converter and the bessemerising finished there4 ,the management of the converters as thus indicated1 and the distribution of the charges among the various converters are left to the head skimmer1 who has control of the converter floor4 ,working of the ,basic-lined ,converter4--,the actual operations of bessemerising in the basic-lined converter differ but little from those where the silica lining is used4 ,one important change has1 however1 been made1 viz43 the introduction of the siliceous flux before the commencement of the blow4 ,the lining having been heated up and 8seasoned10 the charge of four or five ladles-full 7#cj to #dj tons7 of matte is poured into the upright converter through the throat1 #c to #d tons of siliceous flux1 which must be well dried1 are added1 and the blast is turned on gently 7at #e lbs4 pressure71 whilst the converter is slowly turned back--these precautions being necessary in order to prevent excessive blowing out of the dry siliceous fines at the commencement of the work4 ,when the silica is fairly well incorporated1 the blast-pressure is increased to about #aj to #ab lbs4 per square inch1 the blowing is continued for #cj to #de minutes1 and after the silica has been fluxed by the iron oxides--which is tested by feeling the charge with an iron rod inserted through an opening in the breast--the converter is turned over and the slag poured off4 ,a fresh charge of matte and a further quantity of siliceous ore are added and the blowing is resumed1 these operations being repeated several times until the desired quantity of white metal has been accumulated1 which is then blown up to blister copper in the usual manner4 ,during the early stages of the blow1 the operation is largely controlled by judging the quantity of iron remaining in the matte1 from the appearance of small samples which are ladled out of the converter from time to time1 and from this1 the quantity of siliceous material required for the further fluxing is deduced4 ,this material must be quite dry1 so as to flux evenly and not form floaters4 ,one of the advantages of the basic process is that siliceous ores containing values 7the extraction of which may be profitable7 which might not be suitable for use in siliceous linings1 can be conveniently employed as flux in conjunction with the basic lining1 though naturally the best work is done with flux containing a maximum of free silica4 ,the character of the slag is not very different to that produced in the silica-lined converter1 though it is usually lower in silica contents1 and owing to the methods of frequent pouring1 it is lower in copper values4 ,special ,features of ,basic-lined ,converter ,work4--,the basic-lined converter tends to lose heat by radiation and conduction more quickly than does the silica-lined vessel1 due to the walls being thinner and the lining material a better conductor4 ,owing1 however1 to the use of larger charges1 to the increased fuel value of the low-grade mattes1 and to the larger blast-volume used1 heat is retained sufficiently well for the successful operation of the bessemerising process4 ,the temperature is1 however1 generally lower than that obtained when using the siliceous lining1 and constant punching of the tuyeres is necessary--two men being required per shift for this work4 ,the great advantages of the basic lining are connected chiefly with the fact that the frequent relining associated with the silica-lined converter is avoided1 hence an extensive relining plant is not required1 smaller building space and a lighter crane can be used4 ,the use of basic linings further affords a means of extracting the copper and other values from siliceous ores which can be used as flux1 but which might otherwise be difficult to treat1 and it has made possible the cheaper treatment of low-grade mattes4 ,the disadvantages are chiefly those caused by 7a7 ,the use of a material which is not perfectly suited for constructional work1 hence repairs occupy longer time4 7b7 ,the risks of destroying the lining mechanically near the tuyeres1 owing to the extra punching required at these points4 7c7 ,the operation and manipulations requiring extreme care and attention1 owing to the tendency for the production of very high temperature during the great evolution of heat in the early stages of the blow1 when large quantities of iron are being oxidised4 7d7 ,the tendency to losses1 by the blowing out of the dry siliceous ore1 when first turning on the blast4 ,converter ,shop ,organisation4--,the introduction of the basic lining has1 to a large extent1 overcome the necessity for devoting so much shop space to the repair department1 which formerly occupied a very considerable area4 ,the converter stands are usually placed in alignment down one side of the building1 the centre space is kept clear1 and is commanded by the travelling crane for the conveyance of the ladles of matte1 metal1 or slag1 to or from the converters4 ,at ,anaconda1 the converters are charged from a train of matte-ladles mounted on bogies which run along a track behind the converters and situated some distance above them1 the matte being poured down a launder which swings into position over the converter throat4 ,at ,copperhill1 ,tenn41 the converters are charged from ladles which are filled from the blast-furnace settlers situated at the other side of the furnace-building1 whilst at the most modern large plant1 at ,tooele1 ,utah1 the matte is run directly from the reverberatory furnaces to the converters along launders which are nearly #hj feet long and inclined at about #g in #ajj4 ,this method avoids all the handling of matte by cranes and ladles with the attendant troubles of skulls1 breaks-down1 spills1 etc41 and no difficulty has been found in keeping the channel free and open1 nor in supplying matte at a sufficiently high temperature4 ,at ,anaconda and ,tooele1 the side of the converter-shop situated opposite to the converters is devoted to the refining and casting furnaces and to the slag-casting machines4 ,modifications of ,converter ,practice4--7#a7 ,david's ,best ,selecting ,process4--,david devised a special form of converter and suggested a method for conducting in the converter1 instead of in the reverberatory furnace1 the operations of the best 8selecting process0 on the principles of the old ,welsh practice4 ,the method embodied the converting of the matte somewhat beyond the white metal stage1 by which means a small quantity of metallic copper was produced1 in which the whole of the gold and silver values and most of the impurities collected1 the remaining white metal being left tolerably pure4 ,the metallic copper1 thus obtained1 was run into a side pocket in the lining and tapped from there1 the rest of the pure white-metal was blown up to pure best-select copper4 ,illustration3 ,fig4 #fh4--;,general ,view of ,converter ,shop1 ,anaconda4 ,the method is1 however1 too specialised for ordinary commercial copper smelting1 especially when electrolytic refining of the crude metal can be conveniently arranged for4 7#b7 ,the ,haas ,converter4--,the ,haas converter is spherical in form1 and the tuyere holes through the lining are arranged at such an angle as to lessen the pressure required for the forcing of air through the metal4 ,it is claimed for this form that it ensures better mixing of the materials and more even wear on the lining1 by imparting a swirling motion to the bath4 ,references4 ,douglas1 ,james1 8,treatment of ,copper ,matte in the ,bessemer ,converter40 ,trans4 ,inst4 ,min4 and ,met41 #ahii1 vol4 viii41 p4 #a4 ,baggaley1 8,a ,brief ,description of the ,baggaley ,process40 ,heywood1 ,w4 ,a41 8,the ,baggaley ,pyritic ,conversion ,process40 ,eng4 and ,min4 ,journ41 #aijf1 ,mar4 #bd1 p4 #egf4 ,knudsen1 ,e41 8,pyrite ,smelting by the ,knudsen ,method in ,norway40 ,mineral ,industry1 vol4 xviii4 ,moore1 ,redick ,r41 8,copper ,converters with ,basic ,linings40 ,eng4 and ,min4 ,journ41 #aiaj1 ,june #be1 p4 #acag4 ,editorial1 8,improvements in ,copper ,smelting40 ,eng4 and ,min4 ,journ41 #aiaa1 ,mar4 #d1 p4 #dej4 ,schreyer1 ,fr41 8,the ,question of the ,basic ,bessemerising of ,copper ,mattes40 ,metallurgie1 #aiji1 vol4 v41 ,no4 #f1 p4 #aij4 8,improvements at the ,washoe ,smelter40 ,mines and ,minerals1 #aiaj1 ,april1 vol4 xxx41 ,no4 #i1 p4 #ebj4 ,vail1 ,r4 ,h41 8,the ,pierce and ,smith ,converter40 ,eng4 and ,min4 ,journ41 #aiaj1 ,mar4 #ab41 p4 #efc4 ,moore1 ,redick ,r41 8,basic-lined ,converter for ,leady ,copper ,mattes40 ,eng4 and ,min4 ,journ41 #aiaj1 ,aug4 #f1 p4 #bfc4 8,recent ,practice in ,copper ,matte ,converting40 ,eng4 and ,min4 ,journ41 #aiaj1 ,sept4 #c1 p4 #dfj4 ,neal1 ,carr ,b41 8,further ,data on the ,basic ,converter40 ,eng4 and ,min4 ,journ41 #aiaa1 ,june #ac1 p4 #ifd4 ,keller1 ,e41 8,a ,study of the ,elimination of ,impurities from ,copper ,mattes in the ,reverberatory and the ,converter40 ,mineral ,industry1 #aijj1 vol4 ix41 p4 #bdj4 ,mathewson1 ,e4 ,p41 8,the ,relative ,elimination of ,iron1 ,sulphur1 and ,arsenic in ,bessemerising ,copper ,mattes40 ,bull4 ,amer4 ,inst4 ,min4 ,eng41 #aijg1 ,jan4 #g1 ,no4 #ac1 p4 #g4 ,offerhaus1 ,c41 8,operation of an ,anaconda ,converter40 ,eng4 and ,min4 ,journ41 #aijh1 ,oct4 #ag1 p4 #gdg4 ,levy1 ,d4 ,m41 8,the ,successive ,stages in ,bessemerising ,copper ,matte as indicated by the ,converter ,flame40 ,trans4 ,inst4 ,min4 and ,met41 #aiaj41 vol4 xx41 p4 #aag4 ,hixon1 ,h41 8,notes on ,lead and ,copper ,converting40 ,semple1 ,clarence ,c41 8,analyses of ,converter ,fume40 ,eng4 and ,min4 ,journ41 #aiaa1 ,mar4 #aa1 p4 #ejh4 ,haas1 ,herbert1 8,the ,vortex ,copper ,converter40 ,eng4 and ,min4 ,journ41 #aiaj1 ,may #g1 p4 #igb4 ,,lecture ,,ix4 ,,the ,,purification ,,and ,,refining ,,of ,,crude ,,copper4 ,preliminary ,refining and ,casting into ,anodes -- ,electrolytic ,refining -- ,bringing to ,pitch1 and ,casting of ,merchant ,copper4 ,the further treatment of the converter metal depends to a large extent upon its composition1 and the purpose for which it is intended4 ,the matte-smelting operations on copper ores bring about the elimination of the greater part of the constituents accompanying the copper4 ,the converter-grade matte may1 however1 in addition to the copper1 iron and sulphur1 also contain considerable proportions of easily reducible impurities of the ore1 possessing a greater tendency to enter the matte than to be oxidised and eliminated in the slag4 ,such constituents may include gold and silver 7practically all concentrated and retained in the cupriferous product71 arsenic1 antimony1 bismuth1 selenium and tellurium 7retained to very considerable extent71 as well as lead1 zinc1 nickel and cobalt 7in much smaller proportions74 ,the amount of these latter impurities ultimately retained in the converter matte depends very largely upon the proportions originally present in the ore1 and upon the smelting conditions4 ,under the strongly oxidising conditions of the ,bessemer process the copper retains but small quantities of impurity1 and those which do remain in ordinary converter metal may be broadly divided into two classes#ag--7;a7 those which are oxidisable with comparative ease1 and 7b7 those which persist in the metal even under oxidising influences1 unless treated by special means4 ,the former include iron1 sulphur1 and zinc2 the latter1 arsenic1 antimony1 bismuth1 selenium1 tellurium1 gold1 and silver4 ,keller gives the following figures for the average elimination of the impurities in the converter3-- ,iron1 #ii per cent4 ,sulphur1 #ii ,zinc1 #ii ,cobalt1 #ii ,bismuth1 #ig ,lead1 #if ,arsenic1 #ha ,antimony1 #ga ,selenium1 #dg ,tellurium1 #dj ,nickel1 #cg ,of the persistent elements1 the retaining of the gold and silver in the converter-copper is a factor of much economic advantage1 but the other impurities are curiously just those which are characterised by possessing most injurious effects on copper intended for electrical work--for which purpose most of the material is employed4 ,the demand for particularly pure metal in electrical and conductivity work therefore usually necessitates a further purification of the converter-copper 7unless it be an exceptionally pure brand7 and the production of metal specially free from the injurious constituents which persist to a small but sometimes very appreciable extent in the metal under the ordinary oxidising conditions4 ,the presence of silver and gold in the copper may afford in many instances sufficiently good reason for a separating process independently of the market for the pure copper itself4 ,in modern practice1 electrolytic methods are almost universally employed for the purification of the crude copper4 ,by this means the large demands of the present day can be conveniently met1 and the copper be obtained in a condition of remarkable purity4 ,the frequent presence of gold and silver in the metal1 and the convenience and completeness with which they are separated on electrolytic treatment of the copper are particularly advantageous features which recommend the adoption of electro-refining1 and may in some cases be the reason for this procedure even though the metal might otherwise be already quite up to specification for electrical service4 ,in the large majority of cases1 these bullion-values constitute a welcome and independent bye-product1 the returns from which may be set against the expenses of the refining operations on the copper1 which might1 in any case1 be necessary4 ,the process may1 therefore1 be operated with one of the following objects-- 7a7 ,of purifying converter-copper4 7b7 ,of recovering from copper1 the bullion-values which have been collected in the metal4 7c7 ,of manufacturing pure copper1 and recovering the gold and silver as profitable bye-products4 ,under the present industrial conditions1 the electrolytic refineries are located at centres often at very considerable distance from the smelters4 ,situations for the refineries are chosen where the local conditions as regards power supply1 technical resources1 and particularly proximity to markets and distributing centres1 allow of the operations being conducted under the most advantageous circumstances1 and it is customary for smelters situated in the remoter mining districts to ship the crude copper to these custom refineries1 instead of conducting the process themselves4 ,at ,anaconda1 the well-equipped electrolytic refineries have been closed down1 and the anode metal shipped to the ,eastern refineries for treatment4 ,preliminary ,refining of ,converter ,copper and ,casting into ,anodes4--,for modern electro-refining practice1 the crude metal must be prepared into anodes1 which are usually in the form of plates about #b feet #f inches #c feet by #b inches thick4 ,it is found that the metal as produced in the converters1 on being cast into such plates1 does not as a rule yield anodes which work satisfactorily in the tanks4 ,this is largely owing to the impure and crude condition of the metal1 which results in the production of plates which are spongy1 coarse1 and exceedingly rough and uneven on the surface4 ,in consequence the direct employment of such metal would occasion irregularity and difficulties in the operation of the tanks1 giving rise to short circuits1 uneven wear1 breaking off in large pieces1 and similar troubles4 ,furthermore1 the tank liquors and slimes become badly contaminated if large quantities of impurity be present in the anodes1 and the deposition of good clean metal is thus greatly interfered with4 ,all these reasons render it advisable that the converter-copper should1 as a rule1 undergo a preliminary furnace treatment before being cast into anodes4 ,the ,anaconda practice is representative of the manner in which these preliminary refining and casting operations are conducted1 except that the enormous scale and organisation of the operations are practically unique4 ,the principles involved and the general method of operation are in all essentials those of the old ,welsh furnace-refining process4 ,the ,furnace4--,the finished metal from the converters is teemed into ladles1 and from these is poured directly into one of three casting furnaces4 ,two of the furnaces are in constant use1 one of them engaged in refining1 one being filled1 and one in reserve or repair4 ,two of the furnaces are #ad feet #bb feet #h inches hearth dimensions1 with a capacity of #ie tons2 the third has a #ad feet #bh feet hearth1 and a capacity of #aaj tons--the fire-boxes being #e feet #f inches #g feet4 ,the furnace bottom is constructed of the local silica brick 7which is claimed to be the finest in the world7 laid down in four beds1 the three lower being each #ab inches thick1 whilst the working bed is constructed of #bj-;inch bricks2 brick being found to be better than sand in this class of work4 ,the bottom is curved to a depth of #b feet4 ,these furnaces are1 in consequence of their different function1 constructed on somewhat different principles to the reverberatory smelting furnaces4 ,illustration3 ,fig4 #fi4--,sectional ,plan1 ,elevation1 and ,transverse ,sections of ,refining and ,anode-,casting ,furnace1 ,anaconda 7,peters74 ,owing to the high conductivity of copper1 and to the fact that the functions of the furnace are either largely as a medium for simple fusion or as a receptacle for molten metal1 and further1 that but little slag is produced1 that no settling and separation of the fluid materials are required1 and that there is no danger of dusting-losses1 the furnace may conveniently be built with a deep hearth which need not be of very considerable length4 ,the main requirements are refractoriness of the building materials1 particularly careful construction so as to avoid breakouts1 and very strong bracing indeed on account of the deep and heavy bath of material which is carried on the furnace hearth4 ,,operations--7a7 ,oxidation ,stage4--,the furnace is loosely filled with scrap copper which has accumulated round the works 7#h to #ab tons71 and converter metal 7of composition say about #ihc per cent4 copper7 is then poured in at the side door from ladles bringing it in quantities of about #e tons at a time1 as teemed from the converters4 ,when the furnace is about half-filled1 a blast of air at #ij lbs4 pressure is injected through the metal by means of iron pipes1 which at this stage just dip below the surface4 ,these pipes are gradually eaten away by oxidation and slagging action1 but as the end wears down1 the pipe is pushed further in4 ,the function of this air blast is to supply oxygen for the purpose of acting upon the small quantities of oxidisable impurity which remain in the metal after bessemerising1 and which consist chiefly of iron and sulphur1 in addition to the small quantities of metalloids4 ,the oxygen partly acts directly on these constituents1 but as already indicated1 the scouring action is to a great extent performed by copper oxide which is produced and which is itself a powerful oxidising agent4 ,the iron appears to be one of the first elements to be removed1 and then a little sulphur1 but this is chiefly eliminated after the iron has been oxidised4 ,the interaction between the copper oxide and the sulphides liberates metallic copper and yields ,,so#b1 which bubbles up through the metal and gives to it an appearance of 8boiling10 by which name this stage is known4 ,too rapid an oxidation during the early stages is dangerous if much sulphur be present1 owing to the evolution of sulphur-dioxide assuming a degree of explosive vigour4 ,up to this point1 the oxygen has been utilised in removing iron1 sulphur1 etc41 which are eliminated as oxides1 so that but little of the oxygen is retained in the metal1 but after the boiling stage is passed1 oxygen is actually absorbed1 the copper now becoming oxidised1 and the oxygen contents of the metal rapidly increase4 ,as in the analogous instance of steel bessemerising1 it appears essential to introduce some excess of oxygen into the metal in order to ensure the complete removal of the oxidisable impurities1 so in copper-refining1 an excess which amounts to about #jg per cent4 of oxygen 7equivalent to about #f per cent4 of ,cu#b,o7 must be introduced4 ,in the refining practice as conducted by the ,welsh process1 much of this aration took place during the slow melting down of the crude blister copper1 and subsequently during the flapping operations with the rabble2 but the use of the air-blast hastens this oxidation considerably1 especially as the metal is now often directly poured into the furnace in a molten condition1 so that oxidation during melting is not possible4 ,it is essential to defer this final oxidation and elimination until it can be conducted at the refining furnaces rather than to attempt it in the converter1 since the refining furnace allows of the operation being performed much more gradually and under better control1 whereas if conducted in the converter1 the necessarily vigorous action would occasion unduly heavy losses of copper in the slag and probably excessive oxidation of the metal4 ,during the aration1 the furnace contents are continually added to1 by additional ladles-full of metal1 and usually by the time the furnace is filled the air-blast has oxidised most of the impurities from the metal4 ,these have entered the slag1 and the copper has become 8dry10 owing to the necessary super-aration4 ,if this stage has not been reached1 the sample often shows 8sprouting0 7also known as 8spewing0 or 8throwing a worm071 which is caused by the escape of ,,so#b1 and indicates that all the sulphur has not been eliminated4 ,in that case the blowing is continued until small samples ladled out from the bath exhibit the characteristics of dry copper1 viz43 the depression down the middle line of the ingot1 brittleness of the metal1 and a purplish brick-like fracture4 ,these preliminary operations may occupy some three or four hours or more4 7b7 ,poling and ,bringing to ,pitch4--,the oxidation having proceeded to the required stage1 the highly cupriferous slag is skimmed off1 after being first thickened with ashes from the fire-grate1 and the poling of the metal is then commenced4 ,this operation is conducted by immersing poles of timber1 three to six at a time1 in the metal1 holding them well under the surface and pushing them further in as the ends burn away4 ,it is essential that the timber should be green and not dry1 and preferably it should be hard wood1 such as birch1 beech1 or oak4 ,the poles are usually as long as possible1 and are from #f to #h inches thick at the butt end4 ,the function of the wood1 particularly during the early stages is1 to a great extent1 mechanical1 and any chemical changes effected are by indirect action4 ,the poling operation really consists of two stages1 the first of which is the final elimination of ,,so#b retained by the metal1 and the last1 the actual reduction of the excess oxide and the 8bringing of the metal to pitch40 ,the green timber1 when inserted into the copper1 liberates large amounts of moisture and reducing gases which agitate the bath considerably and 8shake0 the gas out of the metal more or less mechanically1 replacing1 at the same time1 some ,,so#b by ,,co and hydrocarbons which copper possesses the power of absorbing4 ,when the ,,so#b has been satisfactorily eliminated1 the reduction stage is arrived at1 and this is conducted in a manner similar to the familiar poling operation of the ,welsh process4 ,the surface of the bath is completely covered over with a layer of coke1 anthracite1 or charcoal1 and more poles are inserted4 ,the exact mechanism of the operation has not yet been definitely traced1 but the action of the wood at this stage is partly of a mechanical and partly of a chemical nature4 ,the reducing gases liberated by the charring and destructive distillation of the wood have themselves a reducing action on the oxides which are dissolved in the dry copper1 but an important feature of the action of these gases is the agitation and splashing which they occasion1 thus bringing the molten metal into close and vigorous contact with the layer of reducing carbonaceous material maintained upon the surface of the bath4 ,poles are inserted usually two or three at a time1 and samples are constantly taken and examined for surface indications and for fracture4 ,this preliminary refining operation usually has for its chief object the preparation of a fairly pure metal which will yield a sound1 clean1 and even anode casting1 and which is not required at this stage to pass the rigid mechanical tests essential for the market product4 ,in this case it is therefore usual to carry the poling operation only to such a degree that the samples ladled out and cast into small ingots solidify with the even1 smooth surface desired and which is characteristic of 8tough-pitch copper0--irrespective of any special mechanical properties of the metal4 ,if the test is satisfactory1 the metal is ready for casting4 ,the poling occupies some hours1 and usually from #dj to #ej poles of wood are used up before the metal is in a suitable condition for casting4 ,during these operations the coal fire in the grate is manipulated in a manner best suited to the various stages of the process2 there may thus be an oxidising flame during the early part of the refining1 but the flame must be of a reducing character whilst poling is in progress4 ,casting4--,until comparatively recent years1 the size of the refining furnace has been necessarily limited to small dimensions1 owing to the difficulty in emptying the furnace of large charges4 ,the practice1 as conducted hitherto1 has been based on the familiar method of the old ,welsh process1 viz41 that of ladling out the metal by small hand ladles4 ,this involves so much hand labour1 and requires such a long period of time for its operation as to make practically impossible any attempt to deal with large quantities of metal1 or to lead to any considerable increase in furnace capacity4 ,the chief difficulties to be overcome when operating on large charges of copper by this hand-lading method are those of maintaining the metal at the correct pitch during the lengthy period of ladling2 whilst the large amount of time during which the finished copper has to remain within prevents the furnace being used for its chief purpose1 that of refining more metal4 ,the method of hand ladling was employed for so many years on account of the difficulties of controlling the stream of metal and of tapping the furnace in the usual way--i4e41 through a tap-hole at the lowest point of the bath4 ,these difficulties were due to the very high working temperatures1 to the great weight of metal behind the stream1 which forced it out under great pressure1 and to the high melting point1 conductivity1 and tendency to chill of the copper1 which was apt to cause setting of metal in the tap-hole1 and led to the latter becoming rapidly closed up and useless4 ,regulation of the stream of metal to a gentle flow was impossible under such conditions4 ,with the introduction of casting machines by ,walker1 and the improvements in the methods of tapping by the adoption of the vertical tapping-slot1 these difficulties have been removed1 and the casting of #ajj tons of metal from one of the modern large casting furnaces presents1 to experienced workers1 little practical difficulty4 ,the modern casting machine brings a series of moulds continually under the supply of metal which issues from a large ladle fed continuously from the tapping-slot of the furnace4 ,the method of tapping now used is to allow the copper to gently run out of the furnace1 by gradually lowering the level of a temporary retaining wall which is constructed in a narrow vertical slot in the tapping side of the furnace4 ,illustration3 ,fig4 #gj4--;,indicating ,tilting and ,pouring ,mechanism for ,ladle of ,casting and ,refining ,furnace4 ,this slot1 which is _/-shaped in plan1 extends from the lowest point of the hearth to well above the highest possible level of the liquid metal4 ,it is about #c feet high and #d inches wide1 and whilst the furnace is working it is kept rammed with a mixture of loam and anthracite1 this filling being supported by a series of short transverse bars1 #af inches long and #a inch square in section1 which are set #c inches apart and rest upon lugs fixed to the iron plates which strengthen the furnace-wall4 ,during the operation of casting1 this hard filling can be readily cut away as required and the level of the dam thus gradually lowered at will1 permitting the gentle and continuous overflow of the molten metal4 ,the stream is also regulated by inserting a pole of wood in the opening1 should the flow become too rapid1 and by this means it is kept under absolute control4 ,the molten metal flows along a spout which feeds a small suspended ladle of about #hjj lbs4 capacity1 the supply being so regulated that this ladle is filled sufficiently slowly as not to get ahead of the moulds4 ,the ladle is supported hydraulically1 and is pivoted so that it can be brought forward and tilted for pouring1 and then lowered and moved a slight distance backwards1 to allow the next mould to come into position4 ,on tilting the ladle1 the metal flows gently and without splashing through a three-hole grid in the front--which keeps back slag or cinders--and runs into the mould1 which is rapidly filled4 ,in order to prevent the metal overflowing in the mould1 and also to rapidly cool that portion which forms the lugs of the anode-plate1 a hollow water-cooled block #b feet #f inches long and of #f inches square section1 situated opposite the ladle1 is brought forward hydraulically into such a position that it rests on the mould just against the edge of the lugs4 ,at many smelters the circular form of anode casting machine introduced by ,a4 ,l4 ,walker is employed4 ,this apparatus consists of a horizontal wheel which can be rotated slowly1 carrying a series of arms at the end of which the moulds are supported1 so that they form a broken ring4 ,by the rotation of the machine1 one mould after another can be brought under the ladle and filled4 ,the moulds are pivoted1 so as to allow of tilting1 and when the metal has set1 the ingot is thus dropped into a cold water bosh1 whence it is carried to the yards by a conveyor4 ,at ,anaconda1 the casting machine consists of a series of moulds carried on a platform conveyor which is operated hydraulically--the moulds are attached by bolting them on to the belt through lugs fixed underneath4 ,the moulds are constructed of #a inch cast-iron1 and allow of the production of anode ingots #b feet #f inches #c feet by #b inches thick1 provided with lugs at the corners of one end for the purpose of supporting the plates in the tanks4 ,each mould holds about #efj lbs4 of metal1 and when the anode has been cast1 the ladle is dropped back into position and the mould is moved forward by means of the conveyor belt4 ,after traversing a distance equal to three times its own length1 the ingot becomes fairly solid1 and at a point corresponding to this position the conveyor base inclines slightly upwards4 ,the cake is sprayed gently during its passage over a distance of about #h feet1 the conveyor belt then passes over a pulley-wheel1 and when in a vertical position1 the anode is forced out of the mould by a crowbar and falls into a water bosh1 from which it is carried by another conveyor on to a platform4 ,here it is wheeled to stacks1 examined for flaws1 and weighed4 ,sample anodes are placed on one side1 and the others are packed for shipment to the ,eastern refineries4 ,illustration3 ,fig4 #ga4--,walker's ,anode ,casting ,machine4 ,illustration3 ,fig4 #gb4--;,general ,view of ,tank-room of ,electrolytic ,refinery1 ,perth ,amboy1 ,n4,j4 ,the furnace deals with one charge 7usually of #ajj tons1 but occasionally much more7 per eight-hour shift1 and the casting machine yields #be tons of anodes per hour4 ,samples weighing from #d to #f ozs4 are taken three times per shift from the stream of copper running into the moulds1 by batting the metal into water with a wooden paddle4 ,this method checks very well with drillings taken from the anode plates1 the chief discrepancy feared having been with respect to silver contents1 owing to the tendency of this metal to segregate4 ,the assay of the anode metal at ,anaconda averages copper #iic per cent41 silver #hj ozs4 per ton1 and gold #je oz4 per ton4 ,electro-,refining4--,electrolytic refining was introduced on a commercial scale by ,elkington at ,pembray in #ahfe1 and with the general adoption of the dynamo for the production of power1 dating from about #ahgj1 the process was greatly developed4 ,most of the copper now placed on the market has passed through the electrolytic refinery4 ,system of ,working4--,the method of arranging the electrodes in the depositing tanks which is usually adopted at the great refineries at the present day1 is that known as the parallel or multiple system4 ,in this method of working1 the anodes are all connected to one pole of the circuit1 and the cathodes1 situated between them1 are all connected to the other4 ,in this way1 each tank comprises in reality one large anode and one large cathode1 and the voltage as measured between any two neighbouring electrodes will be the same4 ,the system thus allows of currents at low voltage being employed1 since the voltage is a factor of the number of electrodes in series1 and in consequence danger of short circuiting is lessened4 ,this allows of plates being placed closer together in the tank1 with less danger from this source of trouble4 ,a large number of tanks are employed at the refineries1 and they are usually arranged in series1 the anode plates of one vat being connected to the cathode plates of the neighbouring one1 the current thus passing from one vat to the other through the entire system4 ,various other methods of arranging the electrodes have been favoured from time to time1 and of these the series-system is the most important1 this being still in use at several large refineries1 though it has been generally superseded by the multiple method4 ,the plan underlying the series method was that of avoiding the trouble and expense of preparing and working with the special cathode sheets of pure copper as are necessitated by the multiple system4 ,in the series-method1 each anode was made to serve as a depositing surface for the pure cathode copper produced by the operation1 so that as impure anode copper was dissolved away on one side of the 8anode0-plate1 pure copper was gradually deposited upon the other side4 ,this system appeared1 therefore1 to have several marked advantages to recommend it1 but in practical operation many difficulties in working and several serious disadvantages were encountered4 ,the chief points in favour of the series-system are-- 7a7 ,smaller first cost of the installation1 particularly in the matter of electrical connections1 since the multiple system requires heavy leads running along each side of the tank1 as well as close attention to the providing of good contacts1 in order to connect all the anodes and all the cathodes together with a minimum of current leakage4 ,in the series-method1 the plates are readily connected one to the other4 7b7 ,the great saving of the cost of preparation and arranging for specially pure cathode plates1 this constituting a very important factor in the costs of the multiple process4 7c7 ,the output of metal per vat is greater4 ,on the other hand1 the disadvantages of the system1 except under special conditions1 are very serious4 7a7 ,more scrap is produced and requires re-treating1 owing to the difficulty of separating the new deposit from the remaining portions of old anode1 which often adhere very firmly4 7b7 ,higher voltage through the tanks is required1 owing to the large number of electrodes in series in the bath4 ,hence the danger of current-leakage and short circuiting is greatly increased1 especially when impure anodes are used1 since they tend to produce conducting layers of mud on the bottom of the vat4 7c7 ,the anode plates have to be made particularly smooth and even on the surface1 since in order to lessen the voltage required1 the plates are brought as close together as possible1 in consequence of which1 any excrescences upon the surface greatly increase the danger of short circuiting4 ,preliminary furnace-refining and special straightening of the anodes are therefore essential in connection with the series method4 7d7 ,special tanks are required1 as the protecting lead liner cannot be employed1 since the danger of current-leakage through it is increased1 owing to the higher voltages required4 ,hence special acid-resisting material1 such as slate1 is necessary1 the expense of which is considerable4 7e7 ,the cost of stripping the cathodes is high1 and the operation is often difficult4 7f7 ,the cost of maintaining the plant is greater4 ,the special advantages of the multiple system are that-- 7#a7 ,it is applicable to all grades of metal2 7#b7 ,it permits of either high or low current-density being employed2 7#c7 ,it permits the use of cheaper lead-lined wooden tanks for working2 7#d7 ,anode plates may be used without previous refining1 if so desired4 ,it is1 however1 general to carry out this preliminary refining1 which yields sounder anodes1 keeps the electrolyte purer1 and promotes the more regular working of the electrodes and electrolyte--although some smelters still cast the anodes direct from converter metal4 ,summarising1 it is found generally that-- 7#a7 ,a marked saving is effected in operating the multiple system 7this has been estimated by ,barnett1 at as much as #b per ton of refined metal--#hs4 #d;d472 7#b7 ,a greater efficiency is obtained1 the tank efficiency of the multiple system being #ie per cent4 compared with #ij per cent4 for the series-system2 7#c7 ,less copper is held up in the multiple system1 since less anode copper is required1 under like conditions as regards cathode surface and current density4 ,,outline ,,of ,,the ,,process4--,the electro-refining industry is a highly specialised one1 and the methods of putting the comparatively simple underlying principles into practical operation have assumed great complexity and diversity in detail1 concerning which ,ulke has collected and published much valuable information4 ,the following details have more particular reference to the multiple system of working1 as being the most representative of the electro-refining methods in general use4 ,the outlines of the process constitute the passing of direct electric current through tanks containing acidified solutions of copper sulphate1 employing plates of crude copper as anodes1 and depositing pure metal upon cathode-plates of specially-refined thin sheets of pure copper4 ,the precious metals and most of the impurities of the anode metal are liberated as small insoluble particles which gradually settle to the bottom of the tanks in the form of mud1 soluble constituents1 such as iron and zinc1 first passing into solution4 ,general ,conditions--,anodes4--,the usual dimensions of the anode-plates are #c feet high by #b feet #f inches wide and about #b inches thick2 they are generally cast with lugs1 so as to allow of suspension in the tanks4 ,the anode metal is usually brought by a preparatory operation1 to as high a state of purity as is economically practicable-- 7a7 ,in order to obtain smooth and sound electrodes4 7b7 ,to ensure better working in the tanks4 7a7 ,the necessity for the employment of solid and even anodes has already been indicated2 it allows of closer suspension of the electrodes1 lessens the liability of sprouting and unevenness on the deposits and the irregular wear and breaking up of the anode-plates before they are sufficiently worn away4 7b7 ,the more free the metal is from iron1 sulphur1 zinc1 nickel1 etc41 the purer remains the electrolyte1 since these elements pass into solution at a greater speed than does the copper itself1 and1 gradually concentrating in the tank liquors1 render them more and more impure--the purity of the metal deposited at the cathode being in consequence decreased4 ,the preliminary refining and bringing up to pitch of the metal before casting into anodes1 as already described1 thus has for its object the preparation of electrodes in a suitable mechanical as well as chemical condition4 ,the copper content is rarely less than #ih per cent4 and is often more than #ii per cent4 ,the gold and silver contents are not affected by this preliminary treatment1 nor are1 to any great extent1 the proportions of arsenic1 antimony1 bismuth1 etc4 ,the size of the anode-plate varies somewhat at different refineries1 the usual standard dimensions being indicated above2 the size depends to a large extent upon the facilities for handling the electrodes and on the circuit system operated4 ,there is a tendency at several works possessing suitable facilities1 to increase the size of the electrodes4 ,the ,cathodes4--,the copper is deposited from the electrolyte upon cathode sheets1 which are usually thin plates of pure copper corresponding in size to the anodes4 ,as these sheets cannot be conveniently provided with suitable lugs for suspension1 they are usually made of somewhat greater length than the anodes1 so as to allow of bending over the cross-conductors2 otherwise they are furnished with metallic clips for attachment to these bars4 ,these cathode sheets are prepared by depositing layers of pure metal upon plates of refined copper of suitable surface dimensions and of about inch thickness4 ,each side of these plates1 which are specially smoothed1 is first slightly oiled so as to allow of the subsequent convenient stripping of the sheet when made1 and it is then well coated with graphite in order to present a conducting surface on which deposition can proceed4 ,the cathode-sheets are deposited either in the regular tanks of the refinery or in vats specially devoted to the purpose1 using in that case1 pure electrolyte1 and working in the usual manner4 ,on attaining a thickness of about #a_/be inch1 the sheet is stripped off1 cleaned and clipped ready for use as a cathode4 ,the ,electrolyte4--,the electrolyte is essentially an acid solution of copper sulphate4 ,the average proportions are from #ae to #bj per cent4 of copper sulphate crystals1 and from #e to #aj per cent4 of sulphuric acid--the usual density of the solution ranging from #aab to #abe4 ,the liquid under ordinary conditions of working1 remains reasonably pure for a considerable time4 ,it tends1 however1 to decrease in acidity and to increase in copper contents1 partly owing to the presence of cuprous oxide in the metal1 which passes into solution independently of the indirect transference of metallic copper from anode to cathode4 ,the composition of the tank liquors must1 therefore1 be frequently checked4 ,the gold and silver values do not pass into solution under ordinary working conditions1 and the addition of a small quantity of common-salt or of hydrochloric acid to the vat effectually prevents any silver from remaining in solution in the liquors4 ,a considerable proportion of the arsenic in the tough-pitch anode-copper1 existing as arsenate1 is deposited with the mud residues1 it being insoluble and non-conducting4 ,arsenic in a reduced condition is1 however1 soluble1 and may gradually concentrate in the liquors and contaminate the cathode copper1 unless suitable precautions are taken4 ,some of the reduced arsenic1 moreover1 tends to produce a slimy arsenite of copper1 which1 though insoluble1 exists in a colloidal non-settling form4 ,addition of ammonium sulphate to the electrolyte prevents this formation1 whilst combined aration and heating promote the precipitation of arsenic as insoluble arsenates which settle with the tank slimes4 ,some of the antimony and bismuth tend to first pass into solution1 but for the most part they are precipitated as insoluble basic salts4 ,under suitable conditions with respect to the acidity and copper contents of the electrolyte1 there is little tendency for deposition of these impurities with the copper1 but deviation from the correct composition is liable to cause contamination of the deposited metal4 ,these impurities1 when in solution1 tend to be oxidised by aration1 and this operation greatly encourages their precipitation with the mud4 ,iron readily dissolves in the electrolyte1 forming soluble ferrous sulphate which tends to gradually accumulate in the solution4 ,this contamination spoils the quality of the deposited metal1 and interferes with the process of deposition1 decreasing the conductivity of the bath and thus necessitating higher voltage4 ,aration of the solution1 especially when warmed1 leads to the formation of basic ferric sulphates which are insoluble1 and which therefore accumulate at the bottom of the tank4 ,selenium and tellurium1 which when present most probably exist as insoluble selenides and tellurides of copper or silver1 are also precipitated1 and thus do not find their way into the deposited metal4 ,the copper itself is deposited from the electrolyte on to the cathode-sheets by the action of the current1 whilst at the anodes1 the metal passes into solution1 and the other constituents are either dissolved or precipitated4 ,it follows that in an undisturbed solution1 the liquid near to the cathode becomes gradually impoverished in copper1 resulting in a decrease in the rate of deposition and necessitating greater electrical pressure1 whilst in the neighbourhood of the anode1 the liquor is proportionately stronger in copper and less acid in character4 ,should these conditions continue to any great extent1 the working of the bath is seriously interfered with1 since diffusion proceeds too slowly for uniformity to be restored1 and in order to secure uniform composition of the electrolyte1 it must be maintained in gentle motion by some system of circulation4 ,this agitation and mixing is assisted by the aration of the bath for the purpose of hastening the oxidation and precipitation of several of the impurities--this being effected by blowing through the liquid a gentle supply of air4 ,temperature4--,the electrical resistance of the solution decreases as the temperature rises1 and in practice the bath is maintained at a uniform temperature of #de to #ej ,c4 ,by this means a useful increase in conductivity is obtained1 the strength of the deposited copper being at the same time greatly augmented4 ,electrical ,conditions4--,the electrical factors which mainly control the working of the electrolytic process are those of-- 7a7 ,current density4 7b7 ,voltage4 7a7 ,current ,density4--,the quantity of metal deposited from an electrolyte is proportional to the current which passes1 and to the electro-chemical equivalent of the particular metal4 ,thus a current of one ampere will deposit from copper sulphate solution1 #aahcb grammes of copper per hour1 and the total quantity deposited in any given time is determined by the product of the current1 the time1 and this electro-chemical equivalent 7which is determined experimentally74 ,in practical operation1 a factor which is amongst the most important of those governing the working of a plant1 is the current density1 or current per unit of area of depositing surface1 since from this factor the rate of deposition upon the cathode plates is determined1 and from it the power requirements1 accommodation1 etc41 for the plant are fixed4 ,the current density is subject to wide variation1 but1 as a general rule1 it ranges from #h to #ah amperes per square foot of plate-area4 ,its value is largely dependent upon the speed of working1 the cost of power1 and the composition of the anode metal1 the electrolyte and the desired product1 etc4 ,in general1 high current-density possesses many advantages1 resulting from the fact that it occasions a more rapid deposition4 ,it causes a proportionately greater output1 consequently the stock of metal held back in the tanks is reduced1 and hence there is less capital locked up in the form of metal undergoing treatment1 and less plant and accommodation are required for the same output4 ,the current density permissible is1 however1 limited by the composition of the electrodes and the solution4 ,high current-density causes rapid dissolution of the anodes1 and if the plates are not particularly free from impurity1 the electrolyte rapidly becomes contaminated1 since its dissolving power on the impurities becomes greater with increased electrolytic action1 and this affords less opportunity for the precipitation and settling of the injurious constituents4 ,in consequence1 the cathode copper is contaminated through this mechanical inclusion of impurities1 whilst electro-deposition of some of these materials may also be encouraged4 ,the presence of much silver in the anodes causes the rapid breaking-up of the plates1 especially if the current density be high1 and thus the separation of the values in the slimes is not so efficiently managed4 ,with high values in the anode copper1 it is necessary to reduce the current density to #h or #aj amperes per square foot1 whereas with purer metal a density of as much as #af to #bj may be conveniently employed4 7b7 ,voltage4--,electrical pressure is required in order to force the depositing current through the electrolyte against the resistances in the circuit4 ,the voltage required depends upon the current density1 the composition and temperature of the electrolyte1 the composition of the anodes1 and also upon the general conditions of working4 ,these being constant1 the voltage necessary is largely a factor of the number of electrodes in series in the tank and of the distance apart of the plates4 ,under ordinary circumstances this voltage varies from #ja to about #jc volt4 ,high voltage is to be avoided1 owing to the danger of short-circuiting1 especially in cases where the accumulation of mud in the tanks1 or the impregnation of metallic salts in the tank walls1 or the growth of excrescences upon the plates1 lead to the passage of the current through these conductors rather than through the electrolyte solution itself4 ,short circuiting naturally diminishes the output of the plant4 ,these electrical factors which form the basis of the power requirements of the refinery1 call for careful observation during the progress of the operations in order to ensure successful working and a high efficiency of the plant4 ,the current from the dynamos is brought by heavy leads and is distributed through the sets of tanks in the manner best suited to the installation4 ,at one of the newer works1 dynamos producing about #f1jjj amperes at #abj to #aej volts1 supply sufficient current to operate a set of #djj vats working on the lines just indicated4 ,illustration3 ,fig4 #gc4--;,indicating ,methods of ,suspending and ,connecting ,electrodes 7,perth ,amboy1 ,n4,j474 ,the ,depositing ,tanks4--,the tanks are usually constructed of wood1 such as strong pitch pine1 and they are lead-lined4 ,the cross-section is usually such as will allow a space of about #c inches between the edges of the electrode and the wall1 and a #f-;inch space from the tank-bottom to the lower edge of the plate4 ,the length of the vats varies considerably1 according to the desired output and to convenience of working--#aj to #ae feet being average dimensions4 ,this size of vat will hold #ae to #be anodes together with a corresponding number of cathodes 7#af to #bf74 ,the tanks are arranged across the building in a number of rows which are usually stepped down in stages of about #b to #c inches each1 so as to assist as much as possible the circulation of the electrolyte through the system by gravity1 and the vats are set in pairs with aisle-ways between 7see ,fig4 #gb74 ,leads run along each side of the tank1 the current being conveyed to all the anodes at once by resting one lug of each plate upon the lead which runs along one side of the tank1 carefully insulating the other lug from the conductor situated at the opposite side1 this being used for connecting up the cathodes4 ,the cathode-sheets are suspended from metallic cross-bars1 which rest upon their own conducting lead1 and are carefully insulated from the anode lead at the other side4 ,the solutions are heated by means of steam coils4 ,distribution of the ,electrolyte4--,the necessary circulation of the electrolyte is effected as much as possible by the natural action of gravity4 ,the tanks of the top row in the depositing-house receive a constant supply of fresh solution from upper distributing vats1 whilst old electrolyte is drawn off from near the bottom of the tanks1 and flows over to those on the next and lower level4 ,fresh solution thus enters at the top of the tank1 old solution is drawn off from below1 and thus a uniform density and composition is maintained4 ,from the tanks situated at the lowest level1 the solution passes to a well1 and from there is pumped up to the store-tanks or1 when necessary1 to the purifying tanks2 air-pressure pumps being often employed for this work4 ,illustration3 ,fig4 #gd4--;,indicating ,connections for ,circulation of ,electrolyte 7,barnett74 ,in course of time--and under the modern system of working with moderately pure anodes1 this period is of considerable duration--the gradual accumulation in the electrolyte1 of the small quantities of impurity which are dissolved from the anode1 may render the liquid so impure1 that a danger arises of contamination of the cathode copper to such a degree that it becomes unfit for conductivity work4 ,it then becomes necessary to purify the solution4 ,in present-day practice1 this continued accumulation of impurity in the electrolyte is prevented by continuously withdrawing1 for separate purification1 a certain proportion of the electrolyte from the circuit--replacing it by a fresh supply of pure solution from the store-tanks4 ,constant regeneration1 purification and circulation are thus effected1 whilst uniform composition is maintained4 ,after considerable use1 the electrolyte solution gradually tends to increase in copper contents1 and the first stages in the scheme of treatment for the old solution is to recover this excess of copper1 which is effected in tanks known as 8liberating tanks40 ,these are similar in general features to the refining vats1 except that lead plates are employed instead of the copper anodes1 so that the excess metal is deposited without any addition of copper being made to the solution1 from the anodes4 ,in due course1 the desired composition in the electrolyte is once more attained4 ,when the solutions have become too impure for further use in the tanks1 the bulk of the copper sulphate is recovered by evaporation in large pans1 followed by crystallisation in somewhat shallow vats of large dimensions4 ,the crude blue vitriol is further purified by repeated crystallisation1 and any copper which still remains in the solution is then precipitated on scrap iron1 the cement copper being worked through the furnaces again4 ,excess acid is also often recovered on further evaporation of the liquors1 and is employed in the subsequent treatment of the slimes4 ,working4--,in the large modern refineries1 the anodes are carried to and from the tank-house by cars1 and at the tank-room are suspended from frames which are conveyed over the baths by means of overhead electrical cranes of about #aj tons lifting capacity4 ,these rectangular frames correspond in size to the dimensions of the tanks1 and are constructed of steel girders4 ,under the longer sides of this frame a series of hooks project1 upon which the lugs of the anodes rest1 and the hooks are placed at distances corresponding to the eventual position of the plates in the tank1 so that the whole series of anodes can be dumped into position at one operation4 ,the cathodes are placed in a second rack1 and likewise brought into position1 between the anodes4 ,the solution is then turned into the tank1 the current started1 and the refining proceeds1 with a steady flow of liquid circulating through the system4 ,the operations of changing electrodes1 cleaning and reloading occupy about one hour1 and1 but for this manipulation1 the process under normal working is continuous4 ,in ordinary practice1 about #bj to #be lbs4 of copper are deposited daily on each cathode4 ,constant examination is made as to the electrical conditions1 and the composition1 temperature1 and density of the solutions4 ,the anodes usually remain in the bath for a period of about six weeks1 and they are then removed from the tank1 scrubbed1 and sent back to the furnaces to be remelted and re-cast into fresh anodes1 the quantity of such anode scrap under good working conditions amounting to about #i or #aj per cent4 of the original metal4 ,illustration3 ,fig4 #ge4--,tank-house1 showing ,anode ,crane 7,ulke74 ,the cathodes remain in the tanks for about one week1 by which time a deposit of from #aej to #agj lbs4 of pure metal has been obtained upon each4 ,the practice of frequently replacing the cathodes possesses1 among other advantages1 those of maintaining a more even current density over the plates1 of preventing the growth of excrescences and the irregular dissolution of the anodes1 and of lessening the danger of breakdown of the somewhat slenderly suspended cathodes1 by putting less weight on the supports4 ,the removal in one operation of the entire batch of cathodes from the bath is effected by means of the suspended hook-frame1 as employed in charging4 ,the plates are rinsed1 the top edges are cut off and returned with the anode scrap1 whilst the pure electrolytic copper passes to the refining and casting furnaces1 where it is prepared for the market4 ,collection of the ,slimes4--,depending upon the working conditions of the refinery1 but usually at intervals of three months1 the precipitated slimes are collected and the tanks are cleaned out4 ,the quantity of slime deposited is generally not very large1 from #ae to #be lbs4 per tank being a not unusual yield4 ,the current and the supply of solution are cut off1 the plates removed1 the contents of the tank allowed to settle1 the liquid siphoned off to within about #f inches of the bottom1 and the residues are swilled out through a trap at the bottom of the tank4 ,the sludge passes through a sieve that separates the lumps of anode copper which have broken off and fallen to the bottom of the tank1 the slime then passes to the special refinery for treatment4 ,the processes adopted for recovering the gold and silver from this residue are highly specialised1 and belong properly to the technology of refining of the precious metals4 ,modifications of ,electrolytic ,refining4--,great success has not yet attended the attempts which have been made to employ copper matte in the form of anodes in electrolytic refining processes1 and the method is not in operation at any of the great modern works4 ,marchs1 ,hoepfner1 ,siemens-,halske1 ,keith1 and others have introduced processes1 but their practical operation is attended with very great difficulty and but little commercial success4 ,matte is exceedingly brittle and it readily breaks up1 it is a bad conductor and necessitates the use of high voltage1 the solutions become very foul1 and the processes require very special apparatus and equipment4 ,methods for the production1 by electrolytic processes1 of pure copper in forms ready for service1 such as wires or tubes1 have been introduced successfully by a number of workers1 including ,elmore1 ,thomerson1 and ,cowper-,coles4 ,several of these methods are now in apparently successful commercial operation1 and the published results of the working of the processes and of tests on the deposited materials offer considerable promise for their future industrial application for special purposes1 if not for general use4 ,the attaining of the necessary compactness1 toughness1 and strength of the metallic product is aided by the employment of pressure during deposition1 as by burnishers1 or by very rapid rotation of the depositing surfaces in the solutions4 ,details of these processes and products may be found from the references subsequently given4 ,bringing up to ,pitch and ,casting the ,merchant ,copper4--,the final stages in the smelting process from ore to market-metal are those of 8fining10 toughening1 and casting the cathode copper1 the object of these operations being to impart to the metal the chemical composition and mechanical and physical properties which are required in order to fit it for the market1 and also to prepare it into a suitable form for service4 ,in addition to cathode copper1 other forms of the metal1 if of suitable composition1 are also treated with this object4 ,for conductivity copper1 however1 these final operations are conducted on metal from which practically all the impurities have been removed1 but which is not sufficiently tough and homogeneous or which is not in a suitable shape for immediate industrial use4 ,the toughening operation consists almost entirely of adjusting the percentage of oxides in the metal1 partly in order to overcome the influence of any traces of injurious impurity that might remain1 but mainly to exercise the functions previously indicated1 of imparting by its more or less direct action upon the metal1 a definite toughening and strengthening effect4 ,the mechanism of the action is not perfectly understood1 but the recent work referred to in ,lecture ,,ii41 p4 #bh1 affords useful evidence as to its possible mode of action4 ,the actual refining operation and the furnace employed for the process are exactly similar to those used in preparing the metal to ensure the casting of sound ingots1 as already described4 ,the operations consist of a preliminary aration1 by means of which any oxidisable impurity still remaining in the metal is oxidised out1 mainly through the action of copper oxide which is formed during the process in some considerable excess4 ,after the copper has become 8dry0 or over-oxidised1 which condition is characterised by brittleness1 depressed surface1 and brick-like purple-red fracture of the metal1 it is reduced by poling and timbering operations to a definite point1 viz43 until a sample ingot of the metal indicates a maximum of toughness1 accompanied by level surface and bright salmon-coloured silky fracture--it is then of 8tough-pitch0 quality4 ,the furnace employed for the refining has already been described4 ,one of the main features in which it differs from the ordinary modern reverberatory smelting-furnace is that owing to the exceedingly high heat-conducting power of metallic copper1 and to the absence of an insulating layer of non-conducting slag1 there is little danger of much chilling action occurring on the hearth of the furnace2 the temperature may1 indeed1 often become too high rather than too low4 ,in consequence1 it is not so usual to construct the furnace with a very massive hearth foundation as for smelting1 but to build it upon a vault or upon a series of piers4 ,with this type of foundation1 the very considerable1 but practically unavoidable1 absorption of metal in the hearth-material is reduced to a minimum4 ,it is usual to work a charge consisting of scrap and oxide in the furnace before the regular smelting campaign begins in order to 8season0 the hearth4 ,this procedure allows the primary absorption of copper by the hearth-material1 and assists its consolidation1 whilst the action of the oxide promotes a surface glazing which lessens the tendency for further absorption of copper1 and gives a good surface to the working bed4 ,as has been already stated1 the hearth is generally built of brickwork rather than of sand4 ,the furnace is constructed to hold from #hj up to #bjj tons of metal4 ,the method of working differs mainly from that previously described1 in that instead of pouring molten copper into the furnace1 as is usual with converter-metal1 the cathode plates must be charged in a different manner4 ,in order to deal with such a large quantity of charge in this bulky form1 without occupying so much time as to make the whole operation too protracted1 it is usual to employ some form of charging machine rather than to use hand labour for the operation4 ,in some cases a small melting furnace is employed solely for the purpose of preparing the metal in a molten form for feeding into the refining furnace4 ,the type of cathode-charger most used is very similar in operation to the ,welman charger for steel furnaces1 and by its means1 #ajj tons of material can be charged per hour4 ,operation4--,the refining and toughening process is conducted in the six stages of3-- 7a7 ,charging4 7b7 ,melting4 7c7 ,skimming4 7d7 ,oxidation1 by aration4 7e7 ,reduction1 by poling4 7f7 ,casting4 7a7 ,the charging is sometimes conducted in stages1 this being indeed unavoidable when very large quantities of material are worked with1 the bulk of which1 when solid1 would more than fill the furnace4 ,two-thirds or three-quarters of the material may be put in at first and just melted down slowly1 after which the remainder is added4 ,owing to the not infrequent presence of sulphur in the furnace coals1 and to its ready affinity for copper1 resulting in undesirable consequences for the commercial metal1 contamination by this element is usually prevented1 as much as possible1 by giving to the cathodes a wash of lime previous to charging4 7b7 ,the melting is generally conducted somewhat slowly1 so as to allow some oxidation of the metal during this stage1 which may occupy some twelve hours4 ,skimming of slag as it forms1 and subsequent blowing of the copper towards the end of the melting stage are frequently resorted to4 7c7 ,the slag which accumulates1 sometimes in considerable quantity1 is skimmed off as occasion requires4 ,when converter metal of such purity as not to need electrolytic refining is treated directly in the furnace1 much of this slag is converter-slag introduced from the ladle1 and requires to be skimmed off at an early stage4 ,in the usual process of melting cathode-copper1 slag is produced from the last traces of iron which may have remained in the metal4 ,in order to render it sufficiently viscid to be pulled out by the skimmer1 ashes from the fire-grate are thrown upon and rabbled into the slag4 ,this skimming may continue for some time1 and a very rich coppery slag is pulled off1 from which the metal values are subsequently recovered4 7d7 ,the oxidation of the small quantities of impurity still remaining in the metal is completed by the operation of airing1 as already described1 and the action is continued in order to produce a small excess of oxide until the copper is 8dry40 ,the time occupied for this airing is now not very protracted1 since most of the impurities have been previously removed from the metal4 7e7 ,the copper is then brought up to pitch by 8poling0 in the manner previously indicated1 except that at this final stage1 the testing of the metal and the adjusting of the oxygen proportion are conducted with much greater precision than was necessary for the simple production of the sound anode plates4 ,in the present instance1 the character of the metal and its value as a commercial article largely depend upon the care and accuracy with which the correct 8pitch0 is reached and is maintained in the bath during the entire period of casting of the metal4 ,the poling for the 8shaking out0 of the gases is rarely necessary with cathode metal1 and the addition of the cover of carbonaceous material for the purpose of effecting the reduction of the oxides to the desired extent1 is made either at the commencement of poling or else shortly afterwards4 ,after some time1 a series of small samples is taken at intervals1 by means of ladles1 and the surface of the ingot is examined4 ,the depression characteristic of dry copper gradually becomes less marked1 the brick-like fracture appears finer and finer until it becomes silky1 whilst the colour eventually turns to a very delicate salmon-pink4 ,meanwhile the mechanical properties have gradually improved1 signs of brittleness disappear1 and somewhat larger samples of the metal1 which are now taken and tested1 are characterised by a very marked toughness and strength4 ,this is the moment at which the poling must cease4 ,the residual copper-oxide has now reached the proportion which was necessary for the imparting of the best mechanical properties1 and the metal is tough-pitch4 ,the skill of the workman is now exercised to the highest degree1 in maintaining the metal in this condition during the whole of the subsequent casting period4 ,oxidation must be avoided in order to prevent a reversion to dry copper1 whilst any further reducing action removes some of the necessary oxide1 and results in 8over-poling40 ,the metal would then become brittle again1 coarsely fibrous and possibly somewhat spongy in fracture and very pale in colour1 whilst in setting it would show a ridge upon the surface4 ,in that case it would be necessary to 8air0 the metal again until it became dry1 and then to pole it back to the 8tough-pitch0 stage4 ,the copper1 when of correct pitch1 is therefore removed from the furnace and cast at once2 this being readily conducted through the tapping slot1 the level of which is gradually lowered4 ,the metal then flows down the spout to the ladle1 and is poured into the moulds attached to some form of mechanical casting machine2 the ingots being finally dropped into a water-bosh1 weighed1 sampled1 and stacked1 and are then in a condition ready for the market4 ,phosphorus is sometimes employed for giving soundness to the castings1 being added to the bath in small quantities in the form of phosphor-copper containing about #aj per cent4 of the non-metal4 ,although very little of this phosphorus is retained by the metal1 being mostly eliminated as oxide1 special caution is required in employing it for high-grade conductivity copper1 since the effect of very small quantities has a deleterious influence upon the conducting properties4 ,silicon also is used for a similar purpose1 and causes a considerable increase in toughness4 7f7 ,when intended for conductivity work1 the metal is cast into the form of 8wire-bars0 of very varied shape and size1 according to requirements2 thus the #ajj-lb4 bars are about #c feet long by about #c inches square section1 the #ejj-lb4 bars #g feet long by about #d inches square4 ,furnace samples weighing about #a lb4 are drawn down gradually to about -inch wire1 and are tested for conductivity1 as well as for strength and toughness1 occasional analysis being also undertaken1 whilst samples of the wire-bars in market form are similarly examined4 ,illustration3 a b ,fig4 #gf4--,microstructure of ,commercial ,copper containing ,oxygen 7,hofman74 a4 ,calumet and ,hecla copper after #fj minutes' poling4 #jbb per cent4 oxygen #aih per cent4 ,cu#b,o4 b4 ,calumet and ,hecla 8dry0 copper before poling4 #jfd per cent4 oxygen #egf per cent4 ,cu#b,o4 ,compare with ,fig4 #f1 p4 #bh4 7,by permission of ,american ,institution of ,mining ,engineers47 ,references4 ,ulke1 ,t41 8,modern ,electrolytic ,copper ,refining40 7,with complete ,bibliography74 ,peters1 ,e4 ,d41 8,modern ,copper ,smelting0 7#aije74 7,chapter xviii4 by ,m4 ,barnett474 ,mineral ,industry4 ,annual ,review4 ,cowper ,coles1 ,s41 8,an ,electrolytic ,process for the ,production of ,copper ,wire40 ,proc4 ,b'ham4 ,met4 ,soc41 #aijh-i1 p4 #e4 ,schnabel and ,louis1 8,handbook of ,metallurgy10 pp4 #cbg-cfi4 ,wraith1 ,w41 8,sampling ,copper ,anodes at ,anaconda40 ,trans4 ,amer4 ,inst4 ,min4 ,eng41 ,march1 #aiaj4 8,the ,de ,lamar ,electro-,refinery at ,chrome1 ,new ,jersey40 ,eng4 and ,min4 ,journ41 ,jan4 #ac1 #aijf1 p4 #gc4 ,flinn1 ,f4 ,b41 8,electrolytic ,copper40 ,the ,metal ,industry1 ,april1 #aiaj1 p4 #aab1 vol4 ii41 ,no4 #c4 ,greenawalt1 ,w4 ,e41 8,the ,greenawalt ,electrolytic ,process40 ,eng4 and ,min4 ,journ41 ,nov4 #bf1 #aiaj1 p4 #ajfb4 ,see also ,references to ,johnson 7p4 #cd71 ,hofman and others 7p4 #ej71 ,keller 7pp4 #ej1 #bae71 and ,peters 7p4 #hj74 ,,index4 ,a ,accretions in the blast furnace1 #ee1 #abd1 #acj1 #aeh4 ,acidity of electrolyte1 #bca1 #bcf4 ,acid-lined converters1 #aic-bac4 ,acid-making from blast-furnace gas1 #adj1 #adf1 #afg1 #aha1 #ahf1 #ahh-aia4 ,acid-making from roaster gas1 #fc1 #fh4 ,acid-plant1 #aij1 #aia4 ,acid-silicates1 #adh4 ,acids and copper1 #cc4 ,addicks1 ,l41 #bc1 #cd4 ,advantages of basic linings1 #bjb1 #bjd1 #bac1 #bad4 blast furnaces1 #aad4 ,brckner roasters1 #gb4 forced draft1 #he4 high current density1 #bcc4 large grates1 #hd4 reverberatories1 #ia4 long blast furnaces1 #abi4 matte-pool1 #ia4 ,mac,dougal roasters1 #ge1 #gf4 multiple system1 #bbi4 pyritic smelting1 #agg4 roasting1 #fb1 #fg4 sectioning1 #abd4 series system1 #bbh4 upright converter1 #aie4 water-jacketing1 #abc1 #abd4 ,aration in electro-refining1 #bca1 #bcb4 furnace refining1 #bbb1 #bci-bdb4 ,africa1 copper output1 #ae4 ,agglomeration of fines1 #dg1 #ea1 #ee-eg1 #aaj-aab4 ,air and copper1 #cc4 for furnace refining1 #bba1 #bbb1 #bda4 in roasting1 #ff4 -admission in reverberatory work1 #hf4 -holes in reverberatory furnace1 #he1 #hf1 #aja4 -space under blast furnaces1 #acf4 -supply for blast furnaces1 #ada-ade1 #ahh4 converters1 #aie-aih1 #bac4 pyritic smelting1 #agc-ahh4 reverberatory work1 #he1 #ib4 ,airing1 #da4 ,alabaster1 ,r4 ,c41 #aia4 ,alaska copper output1 #ae4 ,alchemists1 #b4 ,allen roaster1 #gj4 ,alloys1 #ah1 #ba1 #cd1 #dj1 #db4 ,alumina in slags1 #adg1 #aej1 #aia4 ,aluminium and copper1 #ba1 #bc4 ,amalgamated ,copper ,company1 #ac4 ,american copper mining1 #g4 production1 #ae4 ,ammonium sulphate in electro-refining1 #bca4 ,anaconda1 #i1 #eb1 #hj1 #aia1 #bbj1 #bdc4 blast-furnace practice1 #abj1 #aij4 blast furnaces1 #abe-abh1 #aff1 #aia4 briquetting plant1 #eg4 ,brckners at1 #gb4 ,casting at1 #bbf4 charge calculations1 #aej4 -cars1 #aed1 #aee4 converter practice1 #aid1 #bja1 #bjg1 #bad-baf4 converters1 #aid1 #aig1 #bjg1 #baf4 copper1 #bbg4 costs of production1 #ad4 refining1 #bai4 reverberatory practice1 #hb1 #he1 #hi1 #ia1 #if-ajd4 roasting1 #gd-gi4 sampling1 #dg1 #dh4 smelting scheme1 #ed4 wet concentration1 #ec4 ,analysis of copper1 #bj1 #dd1 #ej1 #bbg4 costs of oil-fired reverberatories1 #ha1 #ajg1 #ajh4 roasting1 #gi4 ,annealing of copper1 #bh1 #ca1 #cb4 ,anodes1 #bag1 #bai1 #bbf1 #bbi-bch4 ,anode-casting machines1 #bbf4 -copper1 #ed1 #bai1 #bcj1 #bcc1 #bdc4 -scrap1 #bcg4 ,antimony and copper1 #bj1 #bc-be1 #cj-cb1 #dd1 #bjg1 #bag1 #bcj4 in copper matte1 #cg1 #bjg1 #bag4 in electro-refining1 #bag1 #bcj1 #bca4 ,apparatus for roasting1 #ff1 et seq4 7see ,roasting furnaces74 ,appearance of copper-mattes1 #ch1 #ci4 ,apron-plates1 #adj1 #aec1 #aed4 ,arch of reverberatories1 #if4 ,argall roaster1 #gc4 ,argentine copper output1 #ae4 ,argo smelter1 #ga1 #hh4 ,arizona copper output1 #ag4 costs of production1 #ad4 mines1 #h1 #ag4 ores1 #df4 ,arnold1 ,j4 ,o41 #cd4 ,arrangement of electrodes1 #bbg-bbi1 #bcd-bcg4 tanks1 #bcd1 #bce4 ,arsenic in copper1 #bj1 #bc-be1 #bh-cc1 #da1 #dc1 #dd1 #bjg1 #bag1 #bcj4 -matte1 #cg1 #bjg1 #bae1 #bag4 electro-refining1 #bae1 #bag1 #bca4 ,arsenides1 ,roasting of1 #ff4 ,ash-beds1 ,copper-bearing1 #de4 ,aspinall1 #cd4 ,assaying1 #dg4 ,associated ,copper ,smelters1 #g4 ,atacamite1 #dg4 ,atlantic ,mine1 #de4 ,atmosphere of the blast furnace1 #aae1 #ahf4 reverberatory furnace1 #fc1 #ha4 ,auger-,former1 #ef4 ,austen1 ,roberts- #cd4 ,austin1 ,l4 ,s41 #hj1 #ade1 #agj1 #aia4 ,australian copper output1 #ae4 mines1 #g1 #h1 #ae4 ,austria1 copper production1 #ae4 ,azurite1 #dg4 ,b ,baggaley1 #aid1 #bjj1 #bjb1 #bae4 ,balakala1 ,cal41 #ge4 ,baltic ,mine1 #ad4 ,baltimore ,company's ,smelter1 #aid4 ,barilla1 #de4 ,barnett1 ,m41 #bbi1 #bce1 #bdc4 ,barrel-shaped converters1 #aic-aig4 ,barring of blast furnaces1 #abd1 #abg1 #acj1 #aeh1 #ahe4 ,bases in slags1 #adh-aej1 #agf1 #ahj1 #aha4 ,basic converter practice1 #ea1 #aha1 #aic-bjb1 #bab-bae4 linings1 #aic-aig1 #bjj1 #bjb1 #bjd1 #bjg1 #bab-baf4 silicate slags1 #adh1 #adi1 #agf1 #agi1 #ahj1 #ahc4 ,bauer1 #ej4 ,bedding systems1 #aef4 ,beds of refining furnaces1 #bai4 reverberatory furnaces 7see ,hearths74 ,bending tests for copper1 #bj4 ,bengough1 ,g4 ,d41 #bh4 ,bessemer1 #agj1 #aib1 #aie4 ,bessemerising of copper mattes1 #db1 #ea1 #aia1 #aic-bag4 of low-grade matte1 #ea1 #aic4 in pyritic smelting1 #agb-ahb4 ,best select copper1 #dj1 #db1 #dd1 #bad1 #bae4 selecting process1 #i1 #dj1 #bad1 #bae4 ,bi-silicate slags1 #adh1 #adi4 ,bismuth in copper1 #bc1 #cj-cc1 #dd1 #bjg1 #bag1 #bcj4 bessemerising1 #bag4 electro-refining1 #bca4 refining1 #bag1 #bcj4 ,black copper1 #dc1 #dd4 ,black copper smelting1 #aae1 #aaf4 ,blast for blast furnaces1 #abe1 #afj1 #afa4 converters1 #aie-aih1 #bjg1 #bac1 #bae4 pyritic smelting1 #agh-ahd1 #ahh4 sintering1 #eh4 ,blast furnaces1 #eb1 #ee4 furnace1 early forms1 #aj4 practice1 #aac-aia4 smelting1 #aj1 #ec1 #ed1 #fg1 #ajh1 #aaj1 #aaa4 water-jacketing1 #aj 7see also ,water-jacketing74 mains1 #ada4 pressure1 #ace1 #ada1 #aei1 #afj1 #afg1 #ahd1 #ahh4 roasting1 #ea1 #ee-ei1 #hj1 #aaj-aab1 #afi4 ,blister copper1 #da1 #dc1 #dd1 #bje1 #bac4 ,blount1 #cd4 ,blowers for blast furnaces1 #ada4 ,blowing to blister1 #bac-bae4 fine concentrates into converters1 #ee4 of converters1 #aib1 #aie1 #bje-baf4 ,boiler tubes1 ,copper for1 #ai1 #cc4 ,boiling in furnace refining1 #bba4 point1 #bd4 ,bolivia1 copper ores1 #df4 output1 #ae4 ,bornite1 #df4 ,bosh-angle1 #aci4 ,boshes1 #abc1 #ach4 ,boston and ,montana ,smelter1 #aia4 ,bottoms1 ,copper1 #dj4 ,bottom-plate for blast furnaces1 #acf4 ,bottom of reverberatories 7see ,hearths74 ,bracing of reverberatories1 #if1 #ii1 #bba4 ,brasque hearths1 #aag1 #abc1 #acd4 ,brasses1 #ba1 #dj4 ,breadth of reverberatories1 #hi4 ,breakdown of electrodes1 #bcj1 #bcc1 #bcg1 #bch4 ,breast plate1 #aci1 #aei1 #afj4 ,brick furnaces1 #abd4 ,bridging of blast furnaces1 #abe-abg4 ,brinell test1 #cb4 ,bringing to pitch1 #ai1 #bf1 #bh1 #ci1 #dj1 #dc1 #bag1 #bbb1 #bbc1 #bcj1 #bch1 #bda1 #bdb4 ,briquettes in blast-furnace charges1 #aej-aeb4 ,coke in1 #eg1 #aja4 ,briquetting1 #ea1 #ed-eg1 #afi4 ,british copper mining1 #b1 #ef4 production1 #ae4 ,brittleness of crude copper1 #bdb4 ,bronzes1 #ba4 ,brown1 ,w41 #ag4 roaster1 #gj1 #ga4 ,brckner roaster1 #gb1 #ge4 ,introduction of1 #aj4 ,brunton sampler1 #di1 #ej4 ,bullion in electro-refining 7see ,values74 ,bustle pipes1 #ada4 ,butte mining1 #h4 ores1 #df1 #fc4 ,preliminary treatment1 #eb4 ,roasting of1 #fc4 ,c ,cadmium in copper1 #bc4 ,calculation of blast-furnace charges1 #adf1 #adg1 #aej-aeb4 ,california1 copper output1 #ag4 ,practice in1 #ge1 #afh4 ,calumet and ,hecla1 #h1 #ad1 #de4 costs of production1 #ad4 ,canada1 copper ores1 #df4 output1 #ae4 ,cananea1 #hj4 blast furnaces1 #acf1 #adb1 #ade1 #aef1 #afa4 ,costs of production at1 #ad4 roasting1 #gh4 reverberatories1 #ia1 #aje-ajh4 settlers1 #afc4 ,capacity of blast furnaces1 #aad1 #abc-abe1 #abi1 #aca1 #ace1 #aea1 #aec1 #agd1 #agi1 #ahd-ahh4 converters1 #aic1 #aie1 #aih1 #bja1 #bjb1 #bjd1 #bjg1 #bab4 electrolytic tanks1 #bca1 #bcd1 #bcg4 refining furnaces1 #bai1 #bbd-bbg1 #bdj4 reverberatories1 #hh-ib1 #ii1 #ajb1 #ajf4 roaster furnaces1 #gj-gb1 #gf-gi4 ,cape ,copper ,company1 #fh1 #gc4 ,carbon and copper1 #bh1 #db4 silicates1 #ci4 dioxide and copper1 #bc4 and acid manufacture1 #aha1 #ahi1 #aij4 in blast-furnace gases1 #aha1 #ahi1 #aij4 monoxide in copper1 #be4 ,carbonaceous fuel in blast furnaces1 #aae1 #aai1 #aba 7see also ,coke74 ,carbonate ores1 #dg4 ,cars for charging1 #ada1 #aec-aee1 #ahf4 ,cast copper1 #cb1 #ce4 ,casting furnaces1 #bai1 #bbj1 #bbd1 #bbe4 machines1 #bbd1 #bbf1 #bdb4 of copper anodes1 #bag1 #bai1 #bbd4 of merchant copper1 #bag1 #bcg-bdb4 ,cathode copper1 #ci1 #dc1 #dd1 #bcj1 #bcc1 #bch1 #bci4 plates1 #bbg-bca1 #bcg4 sheets1 #bbg1 #bcj-bcb1 #bce1 #bcg4 ,caypless1 #cg1 #ej4 ,cement copper1 #dc1 #dd1 #bcf4 ,cerro de ,pasco1 #ge4 ,chalcocite1 #df4 ,chalcopyrite1 #de-dg4 in pyritic smelting1 #aga4 roasting of1 #fe4 ,chambers' briquette machine1 #ef1 #eg4 ,changes during bessemerising1 #bjf-baj1 #bae1 #baf4 ,channelling in reverberatory grates1 #hf1 #aja4 ,channing1 ,j4 ,parke1 #agj1 #ahf1 #aia4 ,charge for blast furnaces1 #acj1 #adf1 #adg1 #aej1 #aea1 #ahg1 #baa4 blast roasting1 #eh1 #aaa1 #aab4 converters1 #bab1 #bac4 pyritic smelting1 #agh-ahj1 #ahg1 #ahh4 reverberatories1 #ajb1 #aaj-aab4 roaster furnaces1 #gf-gi1 #aaa1 #aab4 sintering1 #eh1 #aaa1 #aab4 -cars1 #ada1 #aec-aef1 #ahf4 -sheets1 #aec1 #aeg1 #aeh1 #ahg4 trains for blast furnaces1 #aef-aeh4 reverberatories1 #ii4 ,charging of blast furnaces1 #adj1 #adf1 #aec-aeh1 #agi1 #ahf1 #ahh4 of converters1 #aih1 #aii1 #bjg1 #bjh1 #bab-bad4 of refining furnaces1 #bdj4 of reverberatories1 #he-hg1 #ia-aje -doors1 #ada4 -platform1 #ada4 ,checking of operations1 #dg4 ,chemical properties1 #ah1 #cc4 ,chili bar1 #dc1 #dd4 copper ores1 #df4 production1 #ae4 supplies of copper from1 #g1 #ae1 #de1 #df4 ,chilling in blast-furnace hearths1 #aae1 #aag4 converters1 #aie1 #aii1 #baj1 #bab4 settlers1 #aag4 ,china1 #de4 ,chlorine and copper1 #cc4 ,chromite linings1 #afb4 ,circulation of electrolyte1 #bcb-bcf4 ,claying of reverberatories1 #ie4 ,clean slags1 #aca-acc1 #adh1 #adi1 #ahh1 #baa4 ,cleaning of electrolytic tanks1 #bch4 ,cleaning-out of pyritic furnaces1 #agh-agi4 ,clinkering of reverberatory fire-grates1 #hd1 #he1 #aja4 ,cloud1 ,t4 ,c41 #hj4 ,coal for reverberatory furnaces1 #hi1 #ij1 #aja-ajb1 #aje4 consumption in reverberatory work1 #hd1 #ajb1 #aje4 ,coaling of reverberatories 7see ,firing74 ,cobalt in copper1 #bc1 #bag4 ,coinage alloys1 #ba4 ,coke charging in blast furnaces1 #aec1 #aeh4 consumption in the 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,office work1 #ai4 ,speculation in copper markets1 #aa1 #ab4 8,spewing0 of copper1 #bbb4 ,spindles of ,mac,dougal roasters1 #gd1 #gi4 ,spouts1 #abh1 #aeh-aff4 ,sprouting of copper1 #bbb4 ,stacks of blast furnaces1 #adj1 #afi4 reverberatories1 #hi4 ,staffordshire1 ,copper smelting in1 #d4 ,stages in converting1 #bje1 #bji1 #baj1 #bac1 #baf4 refining1 #bbc4 ,stahl1 #ej4 ,stamping of briquettes1 #eg4 ,stamp-milling of native copper ores1 #ea4 ,statistics of copper1 #ae4 ,staying of reverberatories1 #if1 #ii1 #bba4 ,stays1 ,copper for1 #ai1 #da4 ,steam-pipes1 ,copper for1 #ai4 ,steptoe ,smelter1 ,nevada1 #ge4 ,stevens1 ,h4 ,j41 #ag4 ,sticht1 ,r41 #aga1 #agb1 #ahb1 #ahc1 #aia4 ,storing of matte in blast furnaces1 #acd4 reverberatories1 #id4 settlers1 #ace4 ,stoves for heating blast1 #ade4 ,straightening of anodes1 #bbh4 ,strength of cathode copper1 #ah1 #bcb1 #bch1 #bci4 copper1 #ba1 #cb1 #cc1 #da1 #bch1 #bci1 #bda4 electrolyte solutions1 #bca4 ,stripping of cathodes1 #bbh1 #bcj4 ,sub-silicates1 #adg4 ,success in pyritic smelting1 #aha4 ,sulijtelma ,smelter1 ,norway1 #aid4 ,sulphide ores1 #dc1 #de4 ,preliminary treatment of1 #eb4 ,sulphides1 ,fuel values of1 #aai-abb1 #aeb1 #agj1 #agc1 #agg1 #agh1 #bjc1 #bab1 #bac4 in the blast furnace1 #aac1 #aae1 #aag-aba1 #adg1 #aeh1 #aga-agf1 #ahj1 #ahb1 #ahi1 #aia4 of copper1 #ce-cg1 #ci1 #adf1 #adg ,sulphur and copper1 #cc1 #cf1 #fa1 #adf1 #adg1 #bag1 #bch4 dioxide in blast-furnace gases1 #ahh-aia4 copper1 #be1 #dc1 #bbb4 furnace gases1 #ahi1 #aij4 furnace refining1 #bba-bbc4 gases for acid-making1 #ahi1 #aij4 ,sulphur dioxide in pyritic smelting practice1 #ahb4 elimination in blast-furnace smelting1 #aac1 #aad1 #aag1 #aah1 #abj1 #adf1 #adg1 #aeb4 elimination in blast roasting1 #eh4 elimination in reverberatory smelting1 #ha4 elimination in roasting1 #fe1 #gg1 #gh1 #hh1 #aaj1 #agg4 in blast-furnace charges1 #adf1 #adg1 #aej-aeb1 #agg1 #ahi4 in blast-furnace smelting1 #aaf1 #abj1 #adf1 #adg1 #ahi4 in converting1 #aid1 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#cc1 #dj1 #da1 #db1 #dd1 #bbc1 #bca1 #bch1 #bci4 ,toughening of copper1 #bch-bda4 ,toughness of copper1 #bb1 #be1 #dj1 #bda4 ,trapping of blast1 #aei1 #afj4 ,treatment of converter slags1 #baa4 copper ores1 #dg1 #ej4 fine concentrates1 #aaj-aab4 flue-dust1 #hb1 #ajf1 #ajh1 #aaj1 #aaa1 #afg-afi4 slimes in electro-refining1 #bch4 ,true pyritic smelting1 #aba1 #abb1 #adc1 #adf1 #adg1 #agc1 #agf1 #agh-ahd1 #ahi4 ,turkey1 ,copper output of1 #ae4 ,turnbull 7and ,w4 ,brown71 #ag4 ,tuyeres1 #abb1 #abc1 #ada1 #adb1 #aeh1 #ahe1 #ahh4 for converters1 #aib1 #aic1 #aie1 #aig1 #aih1 #bae4 ,tuyere holes in water-jackets1 #acg1 #adj4 -jackets of blast furnaces1 #ach1 #adj4 -pieces1 #adj4 -zone1 #aga1 #agd-ahe4 ,tyee ,smelter1 ,b4,c41 ,hot blast1 #add4 roasting at1 #fh4 ,typical pyritic smelting charge-sheets1 #bjf4 reverberatory-furnace charge1 #hb4 ,u ,ulke1 ,t41 #bbi1 #bcg1 #bdc4 ,united ,states copper output1 #ae-ag4 ,uses of copper1 #ah4 alloys1 #ba4 ,utah1 copper mining1 #h4 output1 #ag4 costs of production1 #ad4 smelting practice1 #ge4 ,utilisation of heat in reverberatory work1 #hc1 #hg1 #ia4 ,v ,vail1 ,r4 ,h41 #bae4 ,values in anode copper1 #bcj4 converter copper1 #dc1 #bae1 #bah4 slags1 #baa4 copper ores1 #df4 electro-refining1 #bbi-bca1 #bcc1 #bch4 ,varieties of commercial copper1 #ci1 #dj4 ,vats for electro-refining1 #bai1 #bbg-bcj1 #bcd1 #bcg4 ,vein deposits in ,superior1 #de4 ,vertical converters1 #aie4 ,virginia copper ores1 #df4 ,viscosity of slags1 #adh-aej4 ,volatile hydrocarbons in reverberatory smelting1 #he1 #hf1 #aje4 ,voltage for electro-refining1 #bbg1 #bbh1 #bcb1 #bcd1 #bch4 ,vortex converter1 #bae1 #baf4 ,w ,walker1 ,a4 ,l41 #cd1 #aia1 #bbd1 #bbf4 ,wallaroo sintering process1 #eh4 ,walls of reverberatory furnaces1 #ii4 ,wanjukoff1 ,w41 #acb4 ,washoe ,smelter 7see ,anaconda74 ,waste heat in reverberatory-furnace gases1 #hc1 #hg1 #ajg1 #add4 ,utilisation of1 #hc1 #hg1 #ajg1 #adc4 ,water and copper1 #cc4 in blast roasting1 #eh4 -cooling in roaster furnaces1 #gd-gi4 -jacketing of blast furnaces1 #aj1 #aac1 #abb-abd1 #acd-aci1 #aeh1 #ahe4 -supply for jackets1 #abd1 #acg1 #aci1 #adj4 ,watson1 ,d41 #cd4 ,webb1 #cd4 ,welsh process1 #i1 #dj1 #bad1 #bai1 #bbb-bbd4 smelting1 #hb4 ,wethey roaster1 #ga4 ,wet concentration of ores1 #dg1 #ej1 #ec-ee1 #fa1 #fc4 processes1 #dc4 ,white-,howell roaster1 #gc4 ,white-metal1 #dj1 #bje1 #baj1 #bab1 #bac1 #bae4 stage1 #bji1 #baa-bad4 ,white roaster1 #gc4 ,width of blast furnaces1 #abe1 #ace1 #ahd1 #ahf4 reverberatories1 #hi4 ,wintle1 ,f4 ,h41 #aia4 ,wire1 ,preparation of copper1 #ai1 #bch1 #bdc4 ,strength of copper1 #cb4 -bar copper1 #dj1 #bdb4 ,withdrawal of products from blast furnaces1 #abd1 #acj1 #acc1 #ace1 #aeh-aga4 reverberatories1 #hc1 #hf1 #id4 ,work1 ,effects of mechanical1 #cb4 ,working of blast furnaces1 #aad1 #adf1 #aeh1 #agh4 converters1 #agh1 #ahe1 #ahf1 #ahh4 electro-refining plant1 #bbg1 #bcj1 #bcf4 large reverberatories1 #hd1 #ib1 #ig1 #ii4 ,mac,dougal roasters1 #gf-hj4 pyritic process1 #agh1 #ahe1 #ahf1 #ahh4 ,wraith1 ,w41 #bdc4 ,wright1 ,l4 ,t41 #acb1 #ade1 #aia4 ,wyoming1 ,copper production of1 #ag4 ,y ,yunnan1 ,native copper from1 #de4 ,z ,zinc-copper alloys1 #ba1 #bb1 #cd4 -sulphide1 ,roasting of1 #ff4 in copper1 #bc1 #cc4 in electro-refining1 #bbi1 #bcj4 in mattes1 #cg1 #bag4 in slags1 #aej4 ,,bell ,,and ,,bain1 ,,ltd41 ,,printers1 ,,glasgow4 ,griffin's ,metallurgical ,series4 ,,sixth ,,edition1 thoroughly ,revised and considerably ,enlarged4 #ahs4 net4 ,an ,introduction to the ,study of ,,metallurgy4 ,,by ,,sir ,w4 ,,roberts-,,austen1 ,k4,c4,b41 ,d4,c4,l41 ,f4,r4,s41 ,a4,r4,s4,m4 ,revised throughout by ,f4 ,w4 ,,harbord1 ,a4,r4,s4,m41 ,f4,i4,c4 8,professor ,austen's volume will be ,,invaluable40 --,chemical ,news4 ,,fifth ,,edition1 ,revised1 ,considerably ,enlarged1 and in part ,re-written4 ,with ,frontispiece and numerous ,illustrations4 #bas4 ,,the ,,metallurgy ,,of ,,gold4 ,,by ,t4 ,,kirke ,,rose1 ,d4,,sc4,,lond41 ,,assoc4,r4,s4,m41 ,chemist and ,assayer of the ,royal ,mint4 8,a ,,comprehensive ,,practical ,,treatise on this important subject40--,the ,times4 ,,sixth ,,edition1 ,revised throughout and ,enlarged4 ,pp4 i-xx#ech4 ,with #cad ,illustrations1 including #ab ,folding ,plates4 #bas4 net4 ,,the ,,metallurgy ,,of ,,lead4 ,,by ,h4 ,f4 ,,collins1 ,,assoc4,r4,s4,m41 ,m4,,inst4,m4,m4 8,a ,,thoroughly ,,sound and useful digest4 ,may with ,,every ,,confidence be recommended40 ,mining ,journal4 ,,second ,,edition1 ,revised throughout and ,enlarged4 ,at ,press4 ,,the ,,metallurgy ,,of ,,silver4 ,,by ,h4 ,f4 ,,collins1 ,,assoc4,r4,s4,m41 ,m4,,inst4,m4,m4 ,,fourth ,,edition1 ,thoroughly ,revised4 ,two ,volumes4 #cfs4 net4 ,with ,additional ,chapter on ,the ,electric ,smelting of ,steel4 ,,the ,,metallurgy ,,of ,,steel4 ,,by ,f4 ,w4 ,,harbord1 ,,assoc4,r4,s4,m41 ,f4,i4,c41 ,,and ,j4 ,w4 ,,hall1 ,a4,m4,,inst4,c4,e4 ,,third ,,edition1 ,revised and ,enlarged4 ,with many new ,plates4 #afs4 net4 ,,the ,,metallurgy ,,of ,,iron4 ,,by ,,prof4 ,,thomas ,,turner1 ,,assoc4,r4,s4,m41 ,f4,i4,c4 8,a ,,thoroughly ,,useful ,,book1 which brings the subject ,,up ,,to ,,date4 ,of ,,great ,,value to those engaged in the iron industry40--,mining ,journal4 ,frontispiece in ,colours1 and ,beautiful ,series of ,photo-micrographs4 #abs4 #f;d4 net4 ,,alloys and their ,industrial ,applications4 ,,by ,,edward ,f4 ,,law1 ,a4,r4,s4,m4 8,concise and practical 444 will be appreciated by student and manufacturer alike40--,foundry ,trades' ,journal4 ,in ,large #hvo4 ,handsome ,cloth4 ,fully ,illustrated4 #abs4 #f;d4 net4 ,,antimony3 ,its ,history1 ,chemistry1 ,mineralogy1 ,geology1 ,metallurgy1 ,uses and ,preparation1 ,analysis1 ,production and ,valuation4 ,,by ,c4 ,y4 ,,wang1 ,m4 ,a41 ,b4 ,,sc4 8,there is not1 to our knowledge1 any other complete treatise on antimony among all the ,english text-books40--,iron and ,coal ,trades' ,review4 ,,london3 ,,charles ,,griffin ,,co41 ,,limited1 ,,exeter ,,street1 ,,strand4 ,,footnotes3 #a ,this figure indicates thousandths of an inch4 #b ,the term 8impurity0 might in several instances be replaced by the word 8constituent10 since many so-called impurities are purposely added for conferring desired properties on the metal4 ,it is here taken as implying elements other than copper4 #c ,the temperatures given in ,heyn's diagram require revision in the light of later knowledge1 and have been omitted here4 #d ,the treatment of flue-dust is considered later4 #e ,though these actions represent with fair accuracy what occurs on smelting1 there will be indicated later1 in the proper place1 some modification1 due to interactions of certain oxides and sulphides1 in the furnace4 #f ,it might also be possible to assist the concentration in the matte by the addition of any available oxidised ores or residues4 #g ,the chloridising roasting of copper ores is also sometimes employed in connection with wet processes4 #h ,when copper combines with sulphur4 #b;,cu 3 ,cu#b,s 33 #b #fce 3 #b #fce #cb 33 #abg 3 #aei 33 #d 3 #e approximately4 ,when sulphur combines with iron4 ,s 3 ,fe,s 33 #cb 3 #ef #cb 33 #cb 3 #hh 33 #d 3 #aa4 #i ,some flue-dust is also melted down4 #aj ,the ,east ,butte ,copper ,mining ,company has recently reported the successful sintering of its flue-dust by ,dwight-,lloyd machines4 7,see ,mining ,journal1 ,jan4 #f1 #aiab1 p4 #ba74 #aa ,later work on this subject has been published by ,w4 ,wanjukoff3--8,investigations on the ,conditions governing the ,entry of ,copper into the ,slags on ,matte-,smelting1 on the ,chemical ,form in which such ,copper exists1 and on the ,lessening of the ,copper ,losses in ,slags40 ,metallurgie1 #aiab1 ,vol4 x41 ,nos4 #a and #b1 pp4 #a-bg1 ,jan4 #h and #bb1 #aiab4 #ab ,this point will be dealt with in due course4 #ac ,the iron sulphide of a copper matte is probably the eutectic of the iron-sulphide 3 iron series containing about #he per cent4 of sulphide4 #ad ,ducktown ,sulphur1 ,copper1 and ,iron ,company4 #ae ,these views have recently been controverted in an interesting paper by ,g4 ,a4 ,guess4 78,notes on ,pyritic ,smelting10 ,engineering and ,mining ,journal1 #aiab1 ,jan4 #acth1 p4 #aac74 ,he defines ,pyritic ,smelting as the production of a ,ferrous ,silicate ,slag from ,iron ,sulphide ,ore4 #af ,with nickeliferous mattes1 the green colour in the flame is reported by ,heywood to persist throughout the whole process4 #ag ,the case of nickel may be here treated as exceptional4 ,it is eliminated with difficulty1 the nickel and copper tending to oxidise together on bessemerising4 ,transcriber's ,notes3 ,underscores 80 before and after a word or phrase indicate italics in the original text4 ,equal signs 80 before and after a word or phrase indicate bold in the original text4 ,a single underscore after a symbol indicates a subscript4 ,small capitals have been converted to ,,solid capitals4 ,parentheses are used for subscripted numbers1 for example #b is represented by #b as in 8,cu#b,o04 ,illustrations have been moved so they do not break up paragraphs4 ,inconsistent hyphenation has been left as printed1 except 8firebox0 has been changed to 8fire-box0 in the ,index to match the spelling in the main body of the book4 ,typographical errors have been silently corrected but other variations in spelling and punctuation remain unaltered4 ,in some tables 8,number0 has been abbreviated to 8,no401 8,united ,states of ,america0 to 8,u4 ,s4 ,a40 and trailing punctuation has been omitted to make the rows shorter4 ,in some equations an ampersand has been used instead of 8per cent401 again in order to reduce the line length4 ,the advertisements at the beginning of the book have been re-located to the end of the book1 just before the footnote section4