Show THE metallurgy OF LEAD WRITTEN FOR THE MINING REVIEW BY H B E M introduction it is with very considerable reluctance that one begins a discussion of a subject of this nature from one point of view and at many places as actually practiced so simple and straightforward under other conditions complicated extremely technical and in the throes of development considered in its entirety the is altogether too great for complete personal mastery by any one individual some same excel in the dressing ores others in their roasting and still others in smelting smelling sm elting or refining a few men such as percy hotman hofman and collins have had the courage and will to systematically collect and publish information on the subject of late years the smelting smelling sm elting and refining of lead ores in the united states has fallen largely into the hands of two great companies whose operations alone should it be so desired might well occupy more space than we can devote to our entire discussion with the understanding then that it is with almost entire dependence on the accomplishments of others dare we follow through the different sections into which the topic naturally divides itself salt lake city may well be proud of her position as one of the great metallurgical centers of the world besides the historic interest attached to many famous mines found in the mountains about the valley lead smelters shelters sm elters in particular have had romantic careers the slag and vestiges of the old smelters shelters sm elters may still be found in the region about while the murray plant the midvale plant and the new furnaces now in construction at tooele thoele are proof of the present and permanent importance of lead smelting smelling in utah I 1 believe that all utah lead ores contain recoverable amounts of silver this circumstance is true of most workable lead deposits and inseparably unites the metallurgy of the two metals on the other hand silver so often occurs associated with lead that whether the lead is to be saved or not the extraction of the silver becomes a matter in a very great many cases of nothing less than the regular treatment of a lead ore we have plenty of illustrations of the case of silver ores being worked without reference to anything typical of the metallurgy of lead we have plenty of illustrations trat ions of I 1 lead ead ores which are worked into their final products without reference to any silver content a broad survey of the field however assures us that the rule is for lead and nd silver to be associated in their ores and in their extraction the great industry of smelting smelling sm elting lead silver ores depends on this common ori gin of so much of both metals almost every trace of whatever gold is found in such ores is also saved and the same is true in a less degree of any copper that is in the ore when smelted smelter smelt ed it is a condition profoundly significant in mining and milling and smelting smelling sm elting that the minerals of lead iron and zinc commonly occur more or less associated in our great mineral deposits all degrees of association may be found massive or lean sulphides sulp hides may have their galena and pyrite so intermixed as to be practically inseparable by mechanical means again these same minerals may with what despair does a metallurgist see a heavy mixed sulphide ore milled into a lead iron and zinc portion with much loss of mineral in gangue and dust the lead iron part high in sulphur and hardly able to pay treatment while the zinc portion is still carrying too much lead and iron along with the best values in silver away back at the dawn of civilization when we find man first able to make inscription and leave any account of himself he is credited with having long used gold and silver and copper and iron these metals are mentioned in the old inscriptions and writings while the drawing or of a forge and bellows appears equally early there is no evidence that tile the silver came from other bother than lead ores smelting smelling sm elting is accordingly a wonderfully ancient process but in those early times wt W t av till L general view of the knight tintic gintic smelter be found in the rock in isolated layers so that if they cannot be mined apart they at least yield to straightforward and simple treatment the secondary or oxidized minerals of these same metals also occur in aggregates utterly useless for mechanical ch separation or yet in layers so well separated that each may be mined by itself this adds a final complication to the metallurgy of lead besides its being a lead silver metallurgy involving gold and copper only too often iron and zinc are present with possibly gold more in the pyrite portion and silver inclining to separate with the zinc portion with the reduction of simple and rich ores of any of these metals we have acceptably cheap and practical methods better yet some pretty lean ores if equally simple may still pay to work into lead worth 4 cents a pound or zinc worth r 5 cents a pound or into silver at 50 cents the ounce equally true complicated ores of the same minerals and many times as rich may be almost worthless and indeed until well along in the christian era authors more than to mention the subject saw no reason to describe the operation in detail certainly for a long time after silver came into general use with more civilized peoples there was little need for the metal lead if it was known as such its uselessness precluded any attempt to prepare it with advancing civilization lead became known on its own account and is abundantly referred to in the old writings who would not like to be able to see them actually at work those men who lived in egypt or asia minor in the early days it is likely they mined and smelted smelter much as is still done in many places today shallow diggings V are much alike the ithe world around and the simple ore hearth as still considerably C 0 11 sider ably used is not so far removed from the very simplest method we can well imagine mag ne in our metallurgical consideration then lead ores were first useful as supplying silver later the same ores yielded the metal lead at the same time although of quite minor importance as the metal lead there was evidently a great activity in mining ores during those periods when the phoenicians Phoenicia ns the carthaginians and the romans roman were flourishing peoples during the dark ages all mining and smelting smelling sm elting was greatly in abeyance abey ance with the revival of learning the beginnings begin ings of the modern metal era and new discoveries mining and smelting smelling sm elting has again revived and with no other great relapse gradually developed to its present supreme importance the last sixty years which has seen such tremendous developments in science and the metallurgy of other metals has witnessed no commensurate advance in the metallurgy of lead much improvement is of course to be noted shaft furnaces have developed roasting has greatly changed bag houses have been devised the handling of materials has been adapted from other industries and electrolytic refining become a success but the inherently vital and characteristic operations have not so greatly changed the new lead completed at webb city about a year ago is quite up to date but its furnaces are not radically different from those which our best authorities 0 state have been in use for centuries in scotland again comparing past and present metallurgy at our largest and best western smelters shelters sm elters their present success is accompanied by a waste of a tremendous amount of good raw material some plants regularly charge into furnaces 1 per cent of good quality scrap iron as a part of the burden this amounts to about 10 per cent of the lead produced and although it pays commercially gives much good iron a mighty brief service above ground it is not inconceivable that a chunk of minnesota iron ore might leave its longheld resting place one month arrive in pittsburgh the next month changed into a metallic draw head pull some train across the continent the next month and meeting with misfortune become injured and best fit to reduce a little lead and find in its last month final rest as low grade silicate in some great slag dump of far greater consequence is the loss of other metals which the lead smelter turns to seeming oblivion in the huge slag piles chief of these is zinc already spoken of as so frequently accompanying lead ores it is not unknown that a metallurgist shall be considered competent insofar as he is able to smelt zinc in his ores one man may be able to slag 5 per cent zinc another 10 per cent while another is able to waste 15 per cent each is a more capable than his predecessor de cessor if he can handle such material it is successful smelting smelling sm elting but is it successful metallurgy considering the total amount and value of all the zinc thus lost it might well console all ancient fists who flagged their lead to get silver in the same light we may speak of the use of good iron ore to be added for flux in lead smelting smelling sm elting we call it barren iron flux the iron smelter would call it the best grade of hard iron ore there is not the slightest question but that its use is profitable it has no substitute but we inevitably wonder if metallurgy may not so develop that the lead may yet be profitably won and the iron ore reserved for its proper use in the manufacture of iron products the use of limestone flux in quantities however great is not likely to be questioned as of economic loss different the sulphur problem the comparatively small volumes of sulphur trioxide and the stupendous amounts of dioxide thrown off from the lead and copper smelt eries are not only lost but out of place and possibly harmful when emitted into the atmosphere the great phosphate deposits and possible chemical plants of the west lack acid ant yet the smelters shelters sm elters furnish too much for any conceivable use great accomplishments may safely be predicted for that time when they shall get together for their common good it is to this peculiar condition that the developments in the industry bring us in the divisions which follow we may hope to get a glimpse of the history of the subject something of its mineralogy and chemistry more of the metallurgical and engineering problems and a little of the development of the industry at the times and places where it has been most active from small beginnings in colonial times the winning of the west brought under control those areas which have since been developed to yield in the present united states more lead than at present produced by any other nation this in itself is a grand record and when we add to it that we have made a good deal of whatever advance has been accomplished in the art we may feel still more satisfied just now inventors are busy and with both the government and our greatest lead smelting smelling companies attacking the problems of treatment we may expect new advance in the metallurgy of this metal once mined and smelted smelter by slaves for long centuries considered the vilest and basest of all metals but one of the important and useful products of this the age of metals H B armour institute of technology chicago ill |