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[United Engineering Trustees, Inc. ALBERT ROBERTS. '47 R. M. ROOSEVELT, '49 RALPH B. WILLIAMS, '48 The Engineering Foundation F. F. COLCORD. '46 M. A. PRENTIS. Jn.. '48 It. >I. ROOSEVELT. '49]

Jan 1, 1946

By Donald E. Crowell

Due to falling metal prices and depletion of ore reserves, lead- zinc mining in the Leadville, Colo., area gradually came to a halt in the 1950's. Exploration work continued, however, and by 1969 sufficient ore had been blocked out to warrant sinking a shaft and erecting a new concentrator to treat 700 tpd. The new shaft and concentrator were to be located in Iowa Gulch several miles east of Leadville at an elevation of 11,100 ft. The Leadville project is a joint venture between Newmont Mining Co. and Asarco, with Asarco being the operator. Design work began in the fall of 1969. Engineering was done by Torkelson Engineering Co. of Salt Lake City in conjunction with the central engineering department of Asarco. The plant was constructed by Stearns-Roger Corp. Construction began in the spring of 1970 and the plant went onstream in April 1971.

Jan 11, 1972

By Edwin H. McKee

Eruption of rhyolitic ash-flow tuffs in the area of the McDermitt (Cordero) caldera began about 17.4 million yr (m.y.) ago and continued for about 1.5 m.y. During this period of silicic eruptions, a circular area about 30 km in diameter collapsed to form a caldera that subsequently filled with sedimentary and volcanic rocks. A total of more than 200 km30f silicic rocks was erupted from the volcano. The final phase of igneous activity, about 15.0 m.y. ago, included resurgent doming and intrusion in the south-central part of the caldera. Three to 4 m.y. later (-1 2 m.y. ago), hydrothermal solutions using the northern part of the caldera ring fractures as conduits deposited silica, cinnabar, pyrite, alunite, and other minerals in tuffaceous lake beds and volcanic rocks accumulated within the caldera. The ore-forming solutions may have been a residuum from the silicic magma, or connate water, or ground water heated by the still-hot resurgent magma in the central part of the caldera. The source of the mercury and other elements has not been identified.

Jan 1, 1977

By R. Laird Auchmuty

A NUMBER of factors, of varying importance, should be considered in assessing mineral land-here specifically coal land -for tax purposes. (1) Is the coal developed or un- developed'! (2) If undeveloped, is it surrounded by active development in adjoining properties? (3) Accessibility of railroad facilities to the property. Sometimes the railroad itself is of importance. (4) Cost of development of the seam under consideration, whether it can be developed by a drift from the outcrop or whether it will require deep and costly shafts or slopes. (5) Is it definitely known that the coal seam being assessed is of minable thickness and quality on the property? (6) Thickness of recoverable coal from the seam. (7) Quality of the coal. (8) Is the seam being assessed likely to be more costly to mine than other seams in the same district? (9) Is there an active market demand for coal from the seam being assessed? (10) Is the coal held only as protection to surface structures and in such location that it can never be mined? (11) Is the coal in a solid piece or is it in pillars that have been standing for some years as a result of incomplete mining in an old operation? (12) Expected percentage of recovery from the seam being assessed as determined by present mining practice in similar properties. (13) Value of the seam as indicated by sales of similar mineral rights in the immediate district. (14) Current royalty rates of leases for coal in the seam under consideration.

Jan 1, 1939

By Charles H. Fulton

There are comparatively few accurate data on the melting-or the freezing-point temperature of metallurgical slags, or on related physical phenomena, such as fluidity near the melting-point, specific heat, latent heat, etc. With the exception of the work of H. 0. Hofman,' and some older work by R. Akerman, P. Gredt, and H. M. Howe, no information is available that is of direct interest to the metallurgist. Hofman's valuable work is the only one that refers to slags produced in the metallurgy of copper and lead. The classic work of J. H. L. Vogt,2 who views slags from the standpoint of physical mixtures (solutions in which the entities are minerals), has opened up a new field in the study of slags, and has placed the investigation of such properties as melting-temperatures, etc., on a rational basis. The recent work of A. L. Day, E. T. Allen, and W. I?. White, of the Carnegie Institution, at Washington, and of European investigators3 on certain systems of silicate minerals confirms the value of the investigation of silicate series from this standpoint, and it is my aim to apply this method to metallurgical slags, in order to gain exact data of value in metallurgy. The work recorded in the present paper is the result of an investigation of reverberatory-furnace slags made for a Western smelting company to determine exactly the influence of change in composition, within comparatively narrow limits, on the melting-point. For a general discussion concerning the mineralogical character of slags and the principles on which this investigation is based, reference should be made to other work: for the subject is too large to be stated in this paper, except very briefly in the following outline:

Jan 1, 1913

By R. H. Jacoby, M. J. Rzasa

Experimental equilibrium vaporization ratios (K values) were obtained for nitrogen, methane, carbon dioxide, ethane and hydrogen sulfide in two natural gas-absorber oil mixtures and in two natural gas-Elk Basin crude oil mixtures. For each mixture of constant over-all composition, data were obtained at 100°, 150° and 200°F and at various pressures in the range 200 to 5,000 psia. Some effects of composition on the K values were obtained to serve as a guide in choosing K's for engineering calculations on other mixtures. The pressure cell used to obtain the data is a new type and is described here for the first time. INTRODUCTION The phase equilibria of complex hydrocarbon mixtures such as natural gases, crude oils and their mixtures have been studied previously for the purpose of finding equilibrium vaporization ratios for the hydrocarbon constitutents. In a few cases, such non-hydrocarbon.: as nitrogen, carbon dioxide, and hydrogen sulfide were included in the mixture. studied because they occur. in the fluids obtained from petroleum reservoirs. The increasing occurrerce. of these non-liydrocarbon.; antl their growing economic importance. make it necessary to account for them more accurately in engineering calculation.: than is now possible using the meager published data. The available data for non-hydrocarbons may he classified into two groups: namely, binary mixtures of a hydrocarbon and a non-hydrocarbon. and mixtures containing three or more components, only one of which is a non-hydrocarbon. Amon: the former. phase analyses are available for two nitrogen-HC mixtures, tve carbon dioxide-HC mixtures and three hydrogen sulfide-HC mixtures. Data for more complex mixtures are available as follows: Nitrogen-Methane-Pentane'; Nitrogen-Methane-Hexane,'; Nitrogen-Methane-Heptane'; Carbon dioxide-Natural Gas-Natural Gasorline": Carbon dioxide-Natural Gas-Crude Oil". These data have been used generally lor engineering calculations, often with little regard for their precise applicability because data for the non-hydrocarbons in the complex mixtures being dealt with were not available. The use of K values from binary data for calculation:; involving complex mixtures is open to criticism because such K's are not a function of composition and very often show large differences from the K's for the same components in a complex mixture. Thus the effects of composition must be evaluated when obtaining K's for components in complex mixtures. Poettmann and Katz " varied the carbon dioxide content of their mixture.; from about five to ten mol per cent and found substantially no effect on the K values due to this change. This was not surprising since one might expect that changing a minor com-ponent by * three mol per cent would have little effect. It is more important to find the composition change which have the largest effect on the K values. For example. varying the methane or heptanes — plus compositions over a wide rangr may have a large effect on the K'. of all components in the mixture. Interesting data to this effect were obtained by Eilerts and Smith." It was toward these problems that the experimental data presented here were directed. EQUIPMENT The pressure cell used to obtain the data i:. somewhat dif-ferent from those which have been described in the past. Photographs of the equipment are shown in Figs. 1 and 2. Fig. 1 Shows. the front panel: from a .rated position at the right the

Jan 1, 1952

By Herty, C. H.

Iron oxide (FeO) plays an extremely important part in the manufacture of iron and steel. In the three major processes- blast-furnace, open-hearth, and Bessemer converter-iron oxide is the chemically predominant compound and controls to a large ex- tent the operation of the furnaces and the composition and quality of their respective products. In order to emphasize the importance of iron oxide in each process, they will be considered individually in some detail. THE OPEN-HEARTH FURNACE. Iron oxide is introduced into the open-hearth furnace in four ways : 1. The scrap charged into the open hearth is oxidized by the furnace gases, the amount of oxide formed depending primarily on the amount and type of scrap charged. It has been found' that with large scrap, 1.7 Ib. of FeO is formed per 100 Ib. of scrap charged, whereas with scrap of medium size about 5.3 Ib. of FeO is formed per 100 Ib. of scrap charged, when the period between the charging of the scrap and the addition of hot metal is 3 hours. 2. The decomposition of the limestone sets free CO, by the reaction

Jan 1, 1957

By T. V. Philip, R. E. Lenhart

When commercial silicon iron sheets of varying magnetic quality are isothermally annealed at high temperatures, extremely large grains develop in the material having good magnetic properties. These grains are of the (110) [001] orientation and are formed by secondary recrystallization. The primary driving force for this secondary recrystallization is grain boundary free energy. For the secondary grains, activation energies of 103 kcal per mole for nucleation, and of 75.5 kcal per mole for growth, were obtained. The activation energy for nucleation of the secondary grains is consistent with a model involving redistribution of a precipitate acting as the primary grain growth inhibitor. SINGLY oriented silicon iron sheet was first produced in 1935.1 The material as commercially produced today has a very highly developed preferred orientation or texture; up to 95 pct of the grains are crystallographically oriented with their (110) planes in the plane of the sheet and their [loo] directions parallel to the rolling direction. This texture, usually written as (110) [00l], is referred to as the "GOSS" or the "cube-on-edge" texture. Because the magnetic properties of this material are superior to those of the nonoriented sheets in the direction of rolling, the oriented silicon iron has acquired tremendous industrial importance especially in the manufacture of transformer cores and other electrical equipment. The commercially produced material is essentially an iron-silicon alloy containing about 3 1/4 pct Si with minor impurities totaling less than 0.15 pct. The silicon steel heat is melted in the open hearth or electric furnace. The ingots are hot rolled, with or without being slabbed, to strips of 0.100 to 0.080 in. thickness. They are then cold reduced to an intermediate thickness, recrystallized, cold reduced to final thickness, decarburized, and finally annealed at a high temperature. During this high-temperature anneal, extremely large grains with the cube-on-edge texture are produced in the sheet. Several papers have appeared in the literature2-10 relating to the production of the Goss-textured material. Most of these describe the textures produced on cold rolling and on subsequent annealing of single crystal or polycrystalline silicon iron. May and Turnbull11,12 have recently shown the necessity of a second-phase dispersed impurity in the material for the production of the Goss texture. However, none of these papers describes in detail the nucleation and growth kinetics of the (110) [001] grains during the final high-temperature anneal.* The present work, therefore, is an attempt to understand the nucleation and growth kinetics of the cube-on-edge grains in the silicon iron sheet during the final high-temperature anneal.

Jan 1, 1962

By K. M. Rolls, F. W. Reuter, J. Wulff

The superconducting behavior and microstructural characteristics of a nominal Nb-40 wt pct Ti-0.239 wt pct O alloy were studied as a function of ther mo -mechanical processing treatment. Critical current density us applied transverse magnetic field was obtained for 0.010-in.-diam wires at 4.2°Kin steady fields 14 to 110 kG. Both optical metallogvaphy and transmission electron microscopy were used to delineate the micros tructures of the same wires. It wan found that a 1-hr 500°C precipitation heat treatment after cold drawing to final size led to the highest critical current density. Heat treatment at 600°C also led to a high critical current density, but the precipitate differs in kind and form from that at 500°C. The resistire critical field was also found to be sensitive to precipitation heat treatment since the effective composition of the superconducting phase changes. This is discussed in terms of the oxygen in interstitial solid solution. Two types of high-field superconducting wire are at present used in the construction of high-field superconducting solenoids. These types are solid-solution alloy wire such as Nb-Zr and Nb-Ti and composites of the brittle inter metallic compound Nb3Sn. The latter generally have a high super cur rent-carry ing capacity which is difficult to vary if properly made. The supercur rent- carry ing capacity of the former can be varied drastically and often predictably by suitable thermomechanical processing treatments. In general, the critical current density Jc of the solid-solution type of alloy is increased by cold work and by additions of interstitial elements along with aging heat treatments. The imperfections which result are be-iieved to be responsible for the observed increase in Jc. In 1962 Kneip and coworkers1 found that the critical faurrent density of Nb-Zr alloys could be increased by proper heat treatment preceded and followed by cold work. Betterton and coworkers2 using a Nb-25 at. pct Zr alloy found that small additions of oxygen or carbon enhanced the effect of this heat treatment. They suggested that the interstitials present aided precipitation in the alloy, leading to a filamentary structure with superior properties. If the precipitation heat treatment was omitted, interstitial additions had a negligible effect on Jc. wong3 showed that higher heat-treatment temperatures lowered Jc. Walker and co-workers,4 who studied microstructure (by transmission electron microscopy) as well as superconductivity, found that the Jc anisotropy introduced by cold rolling was itself affected by heat treatment. They were unable to clarify the relation between microstructure and critical current density, although evidence of precipitation was indicated. More recent investigation of Nb-Zr alloys,5,6 besides showing that structural defects and fiber ing due to cold work and precipitation serve to raise Jc, also elucidate important optically observable microstructural changes which occur upon precipitation. In these reports, coarsening of the microstructural features was found to decrease Jc. Vetrano and Boom,7 who studied Ti-20.7 at. pct Nb, found that Jc was increased to a maximum by a 415°C, 3-hr heat treatment following quenching from 800°C and cold working. Heat treatments can also affect the resistive critical field Hr. Final-size heat treatments of Nb-Zr wire can lower Hr drastically if gross phase decomposition occurs5'* or moderately if the effects of cold work are eliminated without changing significantly the composition of the phase of interest.3,5,6,8 The percentage of oxygen which can be added to Nb-Zr alloys to enhance Jc is limited by the difficulty of subsequent cold drawing. Since Nb-Ti and Ta-Ti alloys in contrast can tolerate appreciably higher percentages of oxygen, it was decided to investigate the superconducting behavior of various alloys in these systems. The present paper describes the results of adding oxygen to a nominal 40 wt pct Nb alloy as a function of thermomechanical treatment. I) EXPERIMENTAL PROCEDURE A small alloy ingot was prepared from high-purity niobium, iodide, crystal-bar titanium, and Nb2O5 powder by arc melting on a water-cooled copper hearth in a gettered argon atmosphere. The ingot was turned and remelted fourteen times to insure homogeneity. After final melting and rapid cooling, it was machined round to 0.415 in. diam, jacketed in stainless steel, and cold-swaged to 0.117 in. diam. The jacket was removed and swaging continued to 0.051 in. diam followed by wire drawing in carbide dies to 0.010 in. diam. Although it was intended that about 1500 ppm O (by weight) be added, inert gas fusion analysis indicated a 2390 ppm 0 content, apparently due to additional oxygen pickup in the arc furnace. Even so, the alloy was sufficiently ductile to be cold-worked to greater than 99.9 pct reduction

Jan 1, 1967

By AIME AIME

NEARLY two hundred 'engineers attended the dinner given at the Hotel Pennsylvania on Monday-evening, Oct. 10, to the delegation from the American l3nginiering Societies to Great Britain and France when the John Fritz Medal was presented to Sir Robert Hadfield and to Eugene Schneider. Representatives of the British and French Governments ' and of foreign engineering societies gave to the event an international aspect unique in gatherings of engineers. Messages from men distinguished in science, statesmanship and diplomacy were read. Medals struck by the French Government were presented to the general chairman of the deputation, to the chairman of each' individual delegation and to the president's of the four Founder Societies. The meeting was regarded by engineers as formally ushering in a definite movement for world unity in the engineering profession. J. Vipond Davies, president of the United Engineering Society, acted as toastmaster. The speakers ,were Ambrose Swasey, Charles F. Rand, F. B. Jewett, A. S. Dwight, John R. Freeman, all members of the deputa- tion; and M. Gaston Liebert, French Consul General; Captain G. H. Armstrong, British Counsel General; G. G. Clapperton, representing the British Institution bf Electrical Engineers, and Prof. Jacques Cavalier, spokesman for the French universities. Among the engineers from other cities was Governor. James Hartness of Vermont.

Jan 1, 1921

By C. A. Heberlein

C. A. HEBERLEIN,* New York, N. Y.-The results stated by Rey and Brevers are so startling that they are of great interest, as the concentration of a low percentage of cinnabar by differential flotation yields a high-grade concentrate in the presence of either arsenical or iron pyrite. The authors say: "Cyanide can thus be used to depress arsenopyrite and make a good cinnabar-arsenopyrite separation. A cinnabarpyrite separation could probably be effected in the same way." Corrosive sublimate at the present price of mercury would be a very expensive reagent but the expense would be justifiable if a high rate of concentration could be obtained with a high extraction. On my request, special tests were made in the Punitaqui mill in Chile along the line suggested by the authors, without any improvement of either grade or extraction. As the recovery of the cinnabar in a complex sulphide of chalcopyrite and pyrite gave unsatisfactory results, I had tests made at the testing laboratory of the American Cyanamid Co. at Stamford, Conn. As these tests turned out to be highly satisfactory, not only at Stamford but later at the mine, they are presented here. [AMERICAN CYANAMID TEST FEED PER CENT Si02 66.54 A12032.08 CaO0.70 MgO 0.00 Alkalis1.78 Fe15.63 Cu0.44 S9.42 Hg0.45 OZ. PER TON Ag0.95 Au0.151 Screen Analysis of Tailings, Per Cent Plus650.0 Plus 1001.32 Plus 15020.75 Plus 20019.85 Minus 20058.08] The pulp had a density of 22 and a pH of 7.8. Total time of conditioning was one minute. The reagent added was Texas fuel oil, 0.116lb. Of 33.7 Bé. gravity containing 0.9 per cent sulphur. Frother, 0.062 lb. of No. 5 pine oil. Rate of concentration of mercury was 25.7: 1 [ ]

Jan 1, 1941

By Garth M. Crosby, F. McIntosh Galbraith, Bronson Stringham

THE Hercules mine is located in the northeastern section of the Coeur d'Alene district, approximately 1 1/2 miles north of the town of Burke, Idaho. Surface indications of the ore deposit were first discovered in 1886, but regular mine production was not started until 1902 and was continuous until April 1925, when the known ore had been extracted. Incomplete records show that from 1912 until operations were suspended the mine produced 2 1/2 million tons of ore containing 9.4 pct lead and 7.7 oz of silver per ton, together with an estimated 2 pct zinc, 0.3 pct copper, and 20 pct iron. This operation was the first in a series of mining enterprises culminating in October 1947 with the consolidation of Day Mines, Inc. In the same year it was decided to unwater the levels below the collar of the Hercules shaft in the hope of finding some indication of a recurrence of ore. The unwatering operation has been described in a previous paper.1 The initial exploration, following recapture of the workings, showed sufficient promise to warrant a detailed study of the mineralogy with modern techniques.

Jan 12, 1953

EXECUTIVE COMMITTEE OF THE BOARD OF DIRECTORS L E Young. Chairman -. Donald H McLaughlan, Vice-Chairman A B Kinzel Earle E Schumacher John R Suman FINANCE COMMITTEE OF THE BOARD OF DIRECTORS Erle V Daveler, chairrnan Phillip Kraft Clyde E Weed

Jan 1, 1949

By L. D. Jaffe

IT is now well established that quenched and tempered titanium alloys have much better ductility when the quenching is from a two phase a-B structure, rather than from an all B structure. The corresponding microstructural differences, however, have not been shown in previous publications. Accordingly, specimens were cut from a % in. rod of commercial RC-130A, containing 7.9 pct Mn and 0.12 pct C, which had been previously hot rolled, heated 1 hr at 1100°F, and air cooled. (The same heat has been studied by others." 7 Samples about 1/4 in. cube were heated in helium 1/2 hr at 1450' or 1700°F, quenched in brine, tempered in helium 1 hr at various temperatures up to 1250°F, and quenched in brine. They were then sectioned and metallo-graphically examined, using an etchant of HF-HNO, in glycerine. As quenched from 1700°F, the microstructure observed was clear /3. (Probably also present was U, as the hardness was 400 Vhn, but w is not yet reliably revealed by any metallographic technique.) When the /3 quenched alloy was tempered at a high temperature, a precipitated as a grain boundary film

Jan 1, 1957

By M. J. McPherson, R. Venkataramani

R. Venkataramani (Assistant Professor of Mining Engineering, Dept. of Mining, The Pennsylvania State University, University Park, Pa.)-Y. J. Wang and L. W. Saperstein are to be congratulated for their paper on the computer solution of ventilation problems. The limitations on the problem size to be solved by the program (Appendix II) has been outlined in the paper. I would like to add the following additional limitations of this computer program: The dimensions of the variable J1and J2 should be changed to J, (550) and J2 (550) to handle problems containing more than 400 branches, and up to 550 branches. If there are a large number of branches common to the various meshes, another limitation on the problem size will be the dimension of the variable NA. While a higher-order polynomial fitting for the fan characteristic data points is more rigorous, a quadratic relation, if linear interpolation between the points is inadequate, will result in saving computing time without much loss of accuracy. Of course, this can be handled by minor modifications to the existing polynomial fitting routine in the program. M. J. McPherson (Dept. of Mining Engineering, University of Nottingham, Nottingham, England)-The

Jan 1, 1972

By H. C. Howarth

This paper gives observations on ground movement and subsidence resulting from pillar drawing in the Lick Run section of Montour No. 10 mine of the Pittsburgh Coal Co. adjacent to solid coal owned by the U. S. Bureau of Mines at its Experimental mine in Snowden Township, Allegheny County, Pennsylvania. The investigation was planned by George S. Rice, chief mining engineer of the Bureau, who arranged the necessary cooperation with Dr. L. E. Young, vice president of the Pittsburgh Coal Co. Engineers of that company placed permanent monuments on the surface to establish the boundaries of the coal owned by the Bureau and to furnish fixed points to which all levels were referred. Engineers of the Experimental mine staff then covered the ground under observation with a checkerwork of monuments made of oak pegs set into the ground at 50-ft. intervals in two directions at right angles to each other. The level of these pegs was determined first from Dec. 16 to 30, 1929; again from May 25 to June 5, 1930, and finally from July 7 to 15, 1931. Observations were then discontinued because work had been stopped temporarily in this part on Montour 10 mine. General Conditions Fig. 1 is a plan of the part of the area under observation with which this paper deals. The mine is developed on a room and pillar system known locally as half advancing and half retreating. As Nos. 35 and 36 butt entries were advanced, rooms were driven from No. 36 and drawing of the room pillars followed their completion. When the entries reached the boundary, rooms were started from No. 35 butt beginning at that point, and all remaining pillars were drawn as rapidly as possible. The rib lines of Jan. 9 and June 13, 1930, were surveyed a week to 10 days after the first and second sets of levels were run, and there was some advance in that period. The rib line of July 15, 1931, agrees in time

Jan 1, 1934

By Walter Renton, Ingalls

SEVERAL years ago I became interested in computing the historic lead production of the United States, and the mines, or mining districts whence derived. This led me subsequently to an examination of the recent records- of some of the American zinc-mining districts and of the great lead and zinc-mining districts in foreign countries. My present article thus will be to a large extent an addendum to my book, "World Survey of the Zinc Industry," which was published by the Mining and Metallurgical Society of America in 1931, and to which I shall refer hereinafter as Ingalls, op. cit. Throughout this article all expressions of tons mean the ton of 2000 lb. Where original data have been given in metric tons I have converted in many instances simply by multiplying by 1.1, and long tons by 1.12. I have not been fussy about digits and have rounded off many figures. These may explain differences between data herein and other data.

Jan 1, 1946

New York Meets first Wednesday after first Tuesday of each month. L. W. FRANCIS, Chairman, WILLARD S. MORSE, Vice-Chairman,. THOMAS T. READ, Secretary, Woolworth Bldg., New York, N. Y. P. A. MOSMAN, Treasurer. LOUIS D. HUNTOON. - WILLIAM A. POMEROY. Boston Meets first Monday of each winter month. HENRY L. SMYTH, Chairman. ALFRED C. LANE, Vice-Chairman. HENRY A. WENTWORTH, Secretary-Treasurer, 60 India St., Boston, Mass. ROBERT H. RICHARDS, ALBERT SAUVEUR. Columbia Holds four sessions during year. Annual meeting in September or October. FRANK A. ROSS, Chairman. RUSH J. WHITE, Vice-Chairman. LYNDON K. ARMSTRONG, Secretary-Treasurer, P. O. Drawer 2154, Spokane, Wash. FREDERIC KEFFER, FRANCIS A. THOMSON.

Jan 5, 1915

COLORADO SCHOOL OF MINES On February 21, 1918, the students of the Colorado School of Mines who are members or have applied for membership in the Institute re-organized the "Scientific Society of The Colorado School of Mines,? which has for its .purpose the study and discussion of mining problems. Its meetings will be held on the first and third Wednesdays of each month, in Guggenheim Hall. Following are the officers R. W. GIBSON, President, W. A. CONLEY, Vice-president, F. L. SERVISS, Sec'y.-Treas. At present there are 62 members, seven of whom are Faculty members. F. L. SERVISS, Secretary.

Jan 5, 1918

By Nestor Torres-Acuña, Fathi Habashi

Metallic copper of purity equal to commercial electrolytic copper is deposited during the anodic dissolution of technically available white metal, Cu2S, in m acidic solution of' copper(II) sulfate as electrolyte and copper sheets as cathodes. The process may be applied on commercial scale since it has the advantage of by passing the converting and poling steps, decreasing pollution problems due to SO, and recovering the sulfur of the white metal in the elemental form. The anodic dissolution is believed to take place in three steps: The working conditions that lead to 98 pct cathodic current efficiency are: 30 gpl Cu2+ and 100 gpl H2SO4 in electrolyte, current density 1.0 amp per sq dm, and tetnperature of bath 40°C'. DURING the smelting of copper, nickel, lead, and zinc sulfide ores, large amounts of sulfur dioxide are produced. Because the release of this gas in the atmosphere causes pollution problems, many attempts were made in the past for its recovery either in liquified form or processed to sulfuric acid. Although these two forms of sulfur are the usual forms that are consumed by the chemical and metallurgical industries, their storage and transport usually raise economic problems. It was realized, long ago, that a process by which sulfur can be recovered directly in the elemental form would be most attractive. Elemental sulfur is easily stored and transported, and is readily converted to SO2, H2S, or H2SO4 when needed. Processes aimed to recover the metals from their sulfide ores, and at the same time by-product sulfur in the elemental form, were recently reviewed.' As early as 1882, Marchese2 patented a process in which a matte having the composition: Cu 15, Pb 14, Fe 41, and S 25 pct was electrolyzed. According to cohen3 the process was applied on a pilot scale by the Aktiengesellschaft fur Bergbau-, Blei-, und Zinkhiitten-betriebe at Stolberg, Rheinland, Germany. The process was unsuccessful, however, owing to the contamination of the electrolyte during electrolysis. Studies in this field were reported by Bernfeld4 and Egli.5 Borchers et a1.6-8 developed the process further by using white metal (Cu 78.2 pct, S 19.6 pct) instead of the matte, and a pilot plant was operated by the Mansfeldschen Kupferschiefer Co. at Eisleben, German~.~ It appears, however, that the process never went into commercial operation. Further studies in this direction were carried out by Russian workers.10-23 The International Nickel Co. of Canada erected a pilot plant at Port Colborne in 1951 to apply the process to nickel matte which is essentially pure nickel sulfide."'- 26 Full-scale plant went into operation at the Thompson Refinery in Manitoba in 1964.27 In this method nickel sulfide matte is melted and cast into anodes analyzing 76 pct Ni and 20 pct S with small amounts of copper, cobalt, and iron. These anodes are then electrolyzed in an aqueous solution of NiS04 at pH 4. Further work on this method was reported in the literature.28-31 In this paper, experiments on the anodic dissolution of white metal in aqueous copper sulfate solution are reported. EXPERIMENTAL White metal, Table I, obtained from The Anaconda Co., was cast in form of anodes 10 by 7.5 by 1 cm, Fig. 1. The anodes are mechanically strong and do not break easily; when polished they gave a shiny gray metallic appearance. From the chemical composition shown in Table I, it can be seen that the atomic ratio Cu:S corresponds approximately to the formula CU2.06S. The copper in excess to the formula Cu2S is most probably present as a separate phase since metallic copper could be seen under the microscope, Fig. 2. Fig. 3 shows the X-ray diffraction pattern of white metal which matches fairly well with that of reagent-grade Cu2S.

Jan 1, 1969