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By T. H. Weldon, L. V. Whiton, R. R. McNaughton, J. H. Hargrave

Oxygen enriched air is being used quite extensively in the metallurgical plants of The Consolidated Mining and Smelting Co. of Canada, Limited, at Trail, B.C. The oxygen used for this purpose is a by-product from the Company's chemical plants located in the area. Most of the ore treated in the Trail metallurgical plants comes from Com-inco's Sullivan Mine at Kimberley, B.C. At Kimberley the ore is milled to produce lead and zinc concentrates which are shipped to Trail for further treatment to metal. One section of this paper deals with the use of oxygen enriched air in the suspension roasting of the zinc concentrates. In this process the concentrate is calcined for leaching preparatory to electrolytic recovery of the zinc. A second section of the paper describes the use of oxygen enriched air in operations at the lead smelter. There oxygen enriched air is used in the blast to the lead blast furnaces and in the slag fuming furnace which recovers the lead and zinc contained in lead blast furnace slag. The final section of the paper outlines the precautions necessary for the safe use of oxygen enriched air in any plant operation. The Use of Oxygen Enriched Air in the Suspension Zinc Roasters The suspension roasting of zinc concentrate developed at Trail, B.C., has been described in AIME Vol. 121, "The Electrolytic Zinc Plant of The Consolidated Mining and Smelting Company of Canada, Limited" by B. A. Stimmel, W. 11. Hannay and K. D. McBean. Since the publication of that paper, the use of oxygen enriched air in suspension roasting has been introduced as regular practice with marked advantage. The relative importance of a specific advantage may vary with changing conditions, but, in general, it may be stated that improved operation has been achieved at increased capacities. Suspension roasting is carried out at Trail in converted standard 25 ft diam Wedge roasters. The 2nd, 3rd, 4th and 5th roasting hearths have been removed and the drying hearth covered over. Drying of the concentrate is done on the drying hearth and the 1st roasting hearth. The dried concentrate, after any lump's have been broken up in a ball mill, is fed to a single burner located in the upper part of the combustion chamber. Oxygen is introduced at the burner fan along with the gases from drying, returned combustion gases from the waste heat boiler outlet and the required amount of new air. Up to 60 pct of the concentrate settles out on the 6th roasting hearth, the rest passilig out of the roaster. The product collected in the waste heat boiler is finished calcine, but the dust collected in the cyclones after the boilers is returned to the base of the combustion chamber where the sulphate is decomposed. Gases from the c'yclones go to a Cottrell precipitator. The discharges from the 7th roasting hearth and the waste heat boiler are combined with the Cottrell dust to give the finished calcine. Following small scale tests started in 1933, oxygen enriched air has been used continuously in the suspension roasting of zinc concentrate in Trail, beginning in 1937. A significant factor in promoting its use in this operation was the availability of by-product oxygen from the Company's near-by Chemical and Fertilizer Division. To-day it is standard practice at Trail to use oxygen enriched air for zinc concentrate roasting. The most important requirement in roasting a zinc concentrate for an electrolytic plant is that the zinc in the calcine should have maximum solubility. It is also desirable at Trail that the gas produced for the manufacture of suhhuric acid should have a ~naximum concentration of SO2 and that a substantial recovery of waste heat from the gas be achieved. High solubility of zinc requires that the sulphide sulphur and zinc ferrite in the calcine be kept low. These are both functions of temperature and time, with formation of zinc ferrite also dependent on contact between the iron and zinc particles. One of the inherent advantages of suspension roasting is that minimum time and contact are achieved. The limit on temperature is imposed by the fusion point of the concentrate and not by the need to control zinc ferrite formation. Operating temperatures are normally maintained within the limits of 1725" and 1850°F. A relatively low zinc sulphate in the calcine is required at Trail, and this results from discharging the calcine from the high sulphur dioxide atmosphere at a temperature above 1600°F.

Jan 1, 1950

By Allan J. Clark

In his paper on "The Accumulation of Amalgam on Copper Plates,"f Mr. R. T. Baylies records the fact that at the Drumlummon mill, at Marysville, Montana, a series of tests proved that silver, instead of showing a strong affinity with the amalgamated surface of the copper plates, gave evidence of a persistent tendency to escape amalgamation; the fineness of the amalgam, as measured in gold, being highest nearest to the battery, and giving place to a constantly-increasing proportion

Jan 1, 1900

By J. J. Rutledge

On Sept. 4, 1914, Mine No. 1 of the Union Coal Co., Adamson, Oklahoma, suddenly caved, entombing thirteen miners whose bodies were never recovered. The seam of coal mined, the Lower Hartshorne, averaged 5 ft. in thickness and dipped at an angle varying from 22" to 30n. The strata overlying the coal seam were sandstones and shales. The mine was worked by the pillar-and-room method, the rooms being driven directly up the dip of the seam. All coal was blasted off the solid. Rooms were turned on short centers and room pillars were thin and irregular, as shown in Fig. 1. Fig. 2 is a cross-section of the form; showing the mine workings. Some cracks had been observed on the surface, it is said, at least a month before the squeeze occurred, but the collapse of the mine workings came very suddenly. As is usual when squeezes occur on such steep dips and the pillars fail, the crush progressed rapidly down the dip until it reached solid coal; there was a line of break, or draw, over in the solid coal. Several well-defined cracks appeared on the surface, after the mine had squeezed, but there was no appreciable subsidence of the surface, the weight seemed to be thrown entirely to the dip. About one year after the squeeze, and after the workings of the adjoining mine, NO. 4, had been retimbered and made safe, the writer inspected the tenth north (right) entry, or lift, off of No. 4 slope, which was below and fairly near the lowest caved portion of mine No. 1. The roof shale was composed of thin layers, which had been bent in somewhat the same manner as the leaves of a book having flexible covers are bent when the book is folded or rolled up in the hands. Though the mine workings are immediately beneath the streets and buildings of the mining town of Adamson, business was not disturbed by the squeeze, so far as any subsidence of the surface was concerned. No surface monuments were available and no elevations were taken, but the mine workings had been accurately surveyed and traversed, and the streets of the town overlying the mine workings had been carefully platted on the mine map, so that it was possible to locate accurately the cracks on the surface.

Jan 1, 1923

By J. J. Rutledge

On Sept. 4, 1914, Mine No. 1 of the Union Coal Co., Adamson, Oklahoma, suddenly caved, entombing thirteen miners whose bodies were never recovered. The seam of coal mined, the Lower Hartshorne, averaged 5 ft. in thickness and dipped at an angle varying from 22" to 30n. The strata overlying the coal seam were sandstones and shales. The mine was worked by the pillar-and-room method, the rooms being driven directly up the dip of the seam. All coal was blasted off the solid. Rooms were turned on short centers and room pillars were thin and irregular, as shown in Fig. 1. Fig. 2 is a cross-section of the form; showing the mine workings. Some cracks had been observed on the surface, it is said, at least a month before the squeeze occurred, but the collapse of the mine workings came very suddenly. As is usual when squeezes occur on such steep dips and the pillars fail, the crush progressed rapidly down the dip until it reached solid coal; there was a line of break, or draw, over in the solid coal. Several well-defined cracks appeared on the surface, after the mine had squeezed, but there was no appreciable subsidence of the surface, the weight seemed to be thrown entirely to the dip. About one year after the squeeze, and after the workings of the adjoining mine, NO. 4, had been retimbered and made safe, the writer inspected the tenth north (right) entry, or lift, off of No. 4 slope, which was below and fairly near the lowest caved portion of mine No. 1. The roof shale was composed of thin layers, which had been bent in somewhat the same manner as the leaves of a book having flexible covers are bent when the book is folded or rolled up in the hands. Though the mine workings are immediately beneath the streets and buildings of the mining town of Adamson, business was not disturbed by the squeeze, so far as any subsidence of the surface was concerned. No surface monuments were available and no elevations were taken, but the mine workings had been accurately surveyed and traversed, and the streets of the town overlying the mine workings had been carefully platted on the mine map, so that it was possible to locate accurately the cracks on the surface.

Jan 1, 1923

By E. L. Bruce

The district of Patricia, in the province of Ontario, lies northwest of the Albany River and extends northward to Hudson Bay. Formerly this was the unorganized district of Keewatin, the southern part of which was divided in 1912 between the provinces of Manitoba and Ontario. The interprovincial boundary now runs north from Lake of the Woods for 275 miles and thence northeast 375 miles to Hudson Bay. This district is comparable in size to all the older part of Ontario south of the Canadian Pacific Railway east of Lake Huron—thus it is roughly one-third of the whole of the present provincial area. The central part of this great triangle is one of the least accessible parts of Canada. From it streams flow southward to the English River, southeastward to the Albany, northward to Hudson Bay and the Hayes River, and westward to Lake Winnipeg. None of the streams is large and canoe travel is not easy. The only industry it has ever had is the trade in furs. Until the development of the airplane on a commercial basis, the only means of travel was by canoe or dog-train. There is not a mile of railway in the whole district. The two areas to be dealt with lie in the southwestern part of Patricia. Red Lake is 50 miles east of the Manitoba boundary and 75 miles north of the transcontinental railway from Cochrane to Winnipeg. Woman Lake is 50 miles farther east and slightly farther north. The late Dr. D. B. Dowling, of the Geological Survey of Canada, visited Red Lake and spent some time there during his exploration survey from Lac Seul to Berens River in 1893. He also visited the Woman Lake basin during the same journey, but his examination of it was much less detailed, the great area covered by him during the one field season making it impossible to make more than a hurried reconnaissance. Some prospecting in the Red Lake district followed Dowling's exploration, but the distance from railway was too great for any systematic work to be done. In 1922, following the usual plan, the Ontario Department of Mines made a geological reconnaissance of the English River, following :in instrumental survey of that river and its lakes by the Department of Lands. A side trip was taken to examine the rocks of Red Lake described

Jan 1, 1928

By S. C. Lindsay, D. J. I. Evans

With each year that passes hydrometallurgical processes are being more widely used to recover base metals from ores and concentrates. Generally these processes involve liquid-solid separation of metal-bearing liquors from barren residues. This may be done by countercurrent decantation, thickening and filtration, or filtration or centrifuging only. Choice of method is governed by chemical and physical characteristics of the pulps; cost of labor, power, materials, and waste disposal; and even by the amount of capital available when building plans are under way. Since all these controlling factors change with time and location and with technological advances, the separation method must be re-evaluated when new plants or expansion programs are contemplated. At the Sherritt Gordon refinery in Fort Saskatchewan, Alberta, an ammonia pressure leaching process recovers nickel, copper, and cobalt from the nickel concentrate produced at Lynn Lake, Manitoba.' Pregnant liquors are separated from the barren leach residues in a thickener-filter liquid-solids circuit. The decision to use this type of separation was based on a summation of economic factors during the pilot plant and design stages. Although countercurrent decantation was not incorporated in the refinery flowsheet, the problems solved in thickening the leach residues and the experience gained in operating the commercial plant are pertinent to countercurrent decantation, particularly where it is applied to slow-settling leach slurries or slurries having a relatively high vapor pressure of a valuable, obnoxious, or poisonous vapor. The nickel sulfide concentrate is leached under pressure with air and ammonia to dissolve the nickel, copper, and cobalt and most of the sulfur, leaving a residue of iron and siliceous material to be discarded.2,3 During a subsequent distillation stage to recirculate part of the ammonia used for leaching, copper is recovered from the solution as a high-grade sulfide. After further purification to remove traces of copper and undesirable sulfur compounds, the nickel is precipitated by hydrogen under pressure at an elevated temperature. The cobalt, together with unreduced nickel, is precipitated as a mixed metal sulfide by hydrogen sulfide for eventual cobalt recovery. The end solution is then evaporated to produce a crystalline ammonium sulfate byproduct. As shown in Fig. 1, the nickel concentrate is leached in a continuous, two-stage, countercurrent circuit. In the first stage, or adjustment leach, the fresh concentrate is partially leached (60 pct) in the liquor produced in the second stage, or final leach. This system is necessary to produce a solution suitable for treatment in the copper sulfide precipitation step. Both stages are carried out at 170" to 180°F under a total pressure, with air, of 100 to 120 psig in large, horizontal, water-cooled autoclaves. The autoclaves are divided by overflow weirs into four compartments to give a certain amount of staging during leaching. In each compartment a relatively slow-speed (100 to 150 rpm) agitator maintains the nickel concentrate in suspension. Adjustment leaching, carried out in two autoclaves in parallel, is followed by a thickener-filter liquid-solids separation. Final leaching is done in two parallel trains of three autoclaves using aqueous ammonia to extract metal values from the adjustment leach residues. This too is followed by a thickener-filter circuit. Here the residues are repulped once with aqueous ammonia and twice with process water and refiltered after each repulping stage, to insure a maximum recovery of soluble metal, before being discarded to the tailings pond. The adjustment leach is followed by a seven-disk Dorr-Oliver American filter, with an agitator in the filter boot to keep the residues in suspension. Agitators have also been installed beneath the four ten-disk filters following the final leach thickener. Slurry Characteristics: A typical analysis of the Lynn Lake nickel concentrate, produced by differential flotation,' is given in Table I. The concentrate comprises 35 to 49 pct pentlandite, (Fe, Ni)S; 3 to 6 pct chalcopyrite, CuFeS,; 1 to 4 pct pyrite, FeS2; and 24 to 42 pct pyrrhotite, Fe1-2S (where x varies between 0 and 0.2) together with various siliceous minerals such as actinolite, hornblende, and talc. During leaching, the sulfur in the pentlandite, chalcopyrite, and part of the pyrrhotite is successively oxidized through the thiosulfate and poly-thionate radicals to sulfate and sulfamate." Simultaneously the nickel, copper, and cobalt are converted to soluble ammine complexes and the iron in the pentlandite, chalcopyrite, and part of the pyrrhotite is oxidized to a spongy hydrated iron oxide. The hydrated iron oxide is readily broken down by the agitation needed to sustain the concentrate in suspension and to maintain a satisfactory mass transfer of the oxygen from the air to the slurry. Table I shows typical chemical, screen, and

Jan 1, 1961

By Thomas E. Leontis

INTRODUCTION THE importance of magnesium alloys in the manufacture of aircraft engines has been realized for many years. A concentrated effort has been exerted in the laboratories of the Dow Chemical Co. to develop magnesium-base alloys with improved properties at elevated temperatures whereby greater advantage can be taken of the inherent lightness of these materials. In an earlier publication,1 attention was called to the superior tensile properties and resistance to creep of cerium-containing magnesium alloys at temperatures up to 700°F. More recently, additional data on magnesium-cerium alloys have been furnished by Murphy and Payne.2 The present paper deals with the mechanical properties of sand-cast magnesium alloys containing zinc, at temperatures up to 500°F. The study includes binary Mg-Zn† alloys containing up to 10 pct zinc and several ternary and some polynary alloys based on the Mg-1Zn,†Mg-3Zn, Mg-4.4Zn, Mg-6Zn, and Mg-10Zn binaries. The compositional variation in the tensile properties, hardness, and creep at room and elevated temperatures, and in the electrical conductivity at room temperature has been determined. The results of these tests show that many zinc-containing magnesium alloys exhibit resistance to creep at elevated temperatures significantly higher than that of present commercial magnesium alloys, but lower than that of alloys of the magnesium-cerium type. In addition, they have high tensile properties at room and elevated temperatures and high conductivity. This combination of mechanical properties and conductivity indicates that these alloys should be given serious consideration for commercial applications involving exposure to temperatures higher than those to which present commercial magnesium alloys can be taken safely. LITERATURE The properties of sand-cast magnesium alloys containing zinc as a principal alloying element have not been investigated very extensively, especially at elevated temperatures. The following remarks, which are confined to sand-cast alloys, will serve as a summary of the most important references on this phase of magnesium metallurgy. The first recorded determination of the tensile strength of binary Mg-Zn alloys as a function of zinc content was reported by Aitchison.3 Similar studies, including the measurement of elongation and hardness, have been performed by Gann and Winston,4 Dumas and Rockaert,5 Haughton and Prytherch,6 and by Spitaler, the last being reported by Beck.7 A slight superiority in the tensile strength of chillcast Mg + 8 Zn alloy over the sand-cast alloy was noted by Maybrey 8 That alloys of magnesium containing 5 to 12 pct zinc

Jan 1, 1948

By Burt A. Waite

The new OSM regulations for ground water monitoring of underground coal mines have been the source of many concerns for the mining industry. Because the regulations were initially written at the federal level, but are being administered at the state level, considerable confusion still exists within the industry as to what is really required. Based on submission and/or approval of more than 30 monitoring plans for existing mines in Pennsylvania, West Virginia, and Ohio, three basic sections are necessary. They are: 1. background data on the hydrogeologic setting of the mine, 2. the monitoring plan itself, and 3. mining procedures to minimize adverse effects on ground water. Like all of the OSM requirements, ground water monitoring will be a new burden the coal industry must bear, but with proper planning and communication with the regulatory authorities it need not be as bad as originally feared.

Jan 1, 1983

By R. L. Fullman

IN the investigation of metallurgical transformations and the relationships between microstructure and properties of metals, it frequently is desirable to obtain a measurement of the relative amounts of the various phases present and of the mean size of particles into which each phase is dispersed. The relative amounts of the phases can be measured by the classical methods of area, lineal, and point analysis,1-5 in accordance with the principle that the volume fraction of a phase, the fraction of a polished cross section occupied by the phase, the fraction of a random line occupied by the phase, and the fraction of randomly arrayed points occupied by the phase are all equal. The validity of this relationship depends only on the attainment of a truly random sample of area, length, or points, and not on the size, shape, or distribution of the particles constituting the phase. Smith and Guttman8 have derived a relationship between the interface area per unit volume S, and the measurable quantities L., the interface length per unit area on a cross section, and NL, the number of interfaces per unit length intersected by a random line. Their equation, Sv = — L8 = 2NL is also valid regardless of the distribution of particle sizes and shapes. In contrast to the situation concerning measurement of relative fractions of phases and of interface area, the measurement of particle sizes in opaque samples has not been subjected to a complete analysis. It has been common to measure some lineal or area dimension of particles on a polished cross section and to use the mean value as a qualitative measure of particle size. In the present paper, quantitative relationships are established among the various mean dimensions on a polished cross section and the actual dimensions of the particles present. Particles of Uniform Size Spheres: If a metal sample contains particles of a phase a dispersed in the form of spheres of uniform size, a polished cross section through the sample will reveal circular areas of phase a with radii from 0 to ?, the radius of the spheres. Consider a cube of unit dimensions to be cut from the sample. If a cross section parallel to one of the cube faces is examined, the average number of particles per unit area (N,) equals the number of particles per unit volume (Nv) times the probability p1 that the plane would intersect a single sphere positioned at random within the unit cube. Since, of the various possible positions for the cross-sectional plane over the unit length from top to bottom of the cube, only those positions existing over the length 2r would lead to the plane intersecting the sphere, the probability of intersecting a single sphere is just 2r. N8= Nvp1 = Nd-2r [1] Applying the equality of area and volume fractions, the relationship is found between sphere size and average area s of uniform spheres intersected by a random cross section, 4 - f = NV V = Nr . — pra = N s = Nd . 2rs S = —pr2 [2] A similar analysis reveals the average traverse length across spheres of uniform size when random lines are passed through the sample. If a randomly oriented unit cube is cut from the sample and a randomly positioned line is passed through the cube parallel to a cube edge, the number of spheres intersected by the line (Nl) equals the number of spheres per unit volume times the probability p1 of the line hitting a single randomly placed sphere in the cube. Since possible positions of the line occupy unit area, and possible positions for which it will pass through the sphere occupy an area of pr2, the probability of the line hitting a randomly placed single sphere is pr2. NL = Nv p1 = Nvpr2 [3] Combining this relationship with the equality of volume and lineal fraction, the desired relationship is obtained between radius and mean lineal traverse length -i, for spheres of uniform size. 4 - - 3 l=4/3r [4] Circular Plates: Consider a sample containing particles of a phase a in the form of circular plates of uniform radius r and thickness t, where r >> t. If the plates are randomly oriented, as in a sufficiently large sample of a fine grained polycrystalline material, area and lineal analysis may be carried out with parallel cross-sectional planes and lineal traverses. If the plates are not randomly oriented, it is necessary to randomize the orientation of the cross-sectional planes and traverse directions. Let a unit cube be cut from the sample, and a cross-section plane be passed through the cube parallel to one of the cube faces. The number of plates cut by the cross-sectional plane per unit area is equal to the number of plates per unit volume times the probability of a plate intersecting a single randomly positioned and randomly oriented plate in the cube. If J is the component of the plate diameter in the direction normal to the cross-sectional planes, the probability of a plane cutting a single randomly oriented plate is equal to J, the mean value of J for all possible orientations of the plate. Let 4 be the dihedral angle between a plate and the cross-sectional plane, and let p?, d? be the probability that a plate makes an angle between 4 and ? + d? with the cross-sectional plane. Then for ran-

Jan 1, 1954

Abbey, Robert Graham, District Mgr.. The W. W. Sly Mfg. Co., 50 Church St.. New York, N. Y. '21 Abbott, A. N., Mines Supt., Mazapil Copper Co., Ltd Concepcion del Oro, Zac., Mexico. '28 Abbott, Argyle Campbell, Dev. Dept., E. I. du Pont de Nemours & Co., Wilmington, Del. '29 Abbott, Clarence E., V.P., Charge of Raw Materials, Tenn. Coal, Iron & R. R. Co., 1242 Brown-Marx Bldg.. Birmingham, Ala. '04 Abbott, Louis Benjamin, Chief Engr., Elkhorn Div., Consolidation Coal Co., Jenkins, Ky. '16 Abeel, George H., Jr., Cons. Min. Engr Box 427, Santa Monica, Cal. '18 Abel, Albert E., Asst. to Pres., Valley Mould & Iron Corp Hubbard, Ohio. '19 Abel, Raymond L., Asst. Prof., Dept. of Pet. Refin., Univ. of Pittsburgh Pittsburgh. Pa. '28 Abeel, Leo M., Research Engr., Sullivan Concentrator Chapman Camp, B. C., Canada. '31

Jan 1, 1932

By N. J. Grant, B. C. Giessen, M. Morris

The slvuclures of alloys in the system In-Bi have been investigated after (levy vapid queuching from the mell (splat cooling) to -190°C. Tuo-phase fields could be suppressed over most of the tota1 concentvalion range; five melastable phases a1, a2, ?, ?1. and ß exisl, of which four have simple elementtike structures. For example, ß has the A5 struclure of white till. Crystal-tographic data and coordination numbers for these phases aye given, as well as addilional information on the equilibrium diagram, where a new phase In5Bi3 teas found. THE phase diagrams of binary combinations of B elements from the groups B2, B3, B4, and B5 are usually of a simple type and show considerably fewer intermediate phases than combinations of these elements with A metals, transition metals, or the B1 noble metals. Aside from phases such as the typical B3-B5 compounds with the ZnS-B3 structure type, few stoichiometric phases are known; among them are In2Bi and 1nBi.l Nonstoichiometric phases include ß (In-Sn), a1, (In-Pb), and the tin-rich ? phases in the In-Sn, Cd-Sn, and Hg-Sn systems.' The first two phases have a close relationship to indium, while the latter group are known to be structurally related to a Sn. Thus, there are generally no immediate experimental data for the correlation of the crystal structures of B metals and B metal combinations with certain monotonously varying parameters, such as the valence electron concentration (VEC), or the average atomic size. Such parameters have been recognized as structure determining, e.g., for the transition 4 Sn — y phase,2,3 where nonintegral valence electron concentrations are encountered. It should be possible to extend such correlations to other binary systems, if nonequilibrium single-phase alloys could be produced over broad valence electron concentration ranges, and if their crystal structures could be regarded as being imposed by their electronic states. It has been shown in the case of the tin-rich 7 phases3 that alloy phases with typical crystal structures can be produced in B metal alloys rapidly quenched from the liquid to -190°C by the splat cooling technique due to Duwez,3-8 and reviewed in Refs. 5 and 6. The In-Bi system was selected because it extends over a valence electron concentration range in which several metastable, nonstoichiometrir phases could be expected to occur. Further, the low melting points of the known intermediate phases, In2Bi and InBi, Fig. 1(a), indicated low binding energies and thus possibly low driving forces for the formation Of the equilibrium structures. EXPERIMENTAL TECHNIQUES AND RESULTS The preparation of the quenched foils followed the practice described in Ref. 3. Master alloys were produced by melting of indium (99.97+) and bismuth (99.99+) in evacuated Vycor capsules or in an inert gas arc furnace; quantities of 20 mg were splat-cooled onto copper and silver substrates held at - 190°C; and crystal structures and lattice parameters were determined on a GE XRD-5 diffractometer using Cu Ka, radiation at -190°C and at room temperature. The duplication of each run with both substrates permitted the elimination of overlap of the substrate diffraction pattern and that of the investigated substance. The XRD patterns were usually taken from sin2 " = 0.03 to 0.35; the substrate was used as a means of internal calibration. The fractional accuracy of the lattice parameters of metastable phases is approximately 10-3 In the following, all percentages are in atomic percent. The stable and metastable phases found after rapid quenching to -190°C are listed in Table I, together with estimated concentration ranges and crystallographic data. The investigated alloys and phases present in them are given in Table 11. Except for the region between indium with 33 and 50 pct Bi, where a revision of the equilibrium phase diagram became necessary to include a new stoichiometric phase In5Bi3, the diffraction patterns taken after heating to room temperature agreed with those expected from the phase diagram, Fig. l(a). This suggests that the new nonstoichiometric phases are not stable at room temperature, thus following the observations made for the y phases based on tin.3 Results concerning the equilibrium phases In2Bi and In5Bi3 and the revision of the equilibrium phase diagram which is made necessary by the inclusion of In5Bi3 will be treated first. The Crystal Structure of In2Bi. Makarov7 had identified In2Bi as belonging to the AlB2-C32 type ; however, in a later paper the structure was revised.8 In2Bio was found to be of the Ni21n-B8ß type,21 with a = 5.496A, c = 6.57.9A, and N = 6 atoms per unit cell.9 This crystal structure was confirmed in the present work; definite evidence for the doubling of the c axis, as compared to the A1B2-C32 type, and for the proposed order structure, was found in the powder pattern. The observed lattice parameters agree well with those of Ref. 8; those measured at -190°C are given- in Table I. The Crystal Structure of In5Bi3. A new, equilibrium, intermediate phase was identified in slow-cooled, as-cast alloys; it was identified as In5Bi3. The structure has been worked out by Giessen and Grant;" lattice parameters at -190°C are given in Table I. This phase is probably identical with "In3Bi2", produced by vapor deposition techniques, but not recognized as an equilibrium phase by Palatnik et a1.11 After completion of the present work, the existence of In5Bi3 has also been demonstrated by superconductivity measurements on In-Bi alloys.20

Jan 1, 1968

By Thomas N. Walthier

If current trends continue, the shrunken world of exploration will keep on shrinking and the number of new mines will be insufficient to meet production requirements. Mineral shortages-not natural, but government induced-will then occur.

Jan 5, 1976

By Lester Guttman

THE connection between short-range order and thermodynamic activities in binary solid solutions has been pointed out by Birchenall1 who calculated approximate values of the energy of interaction of Zn and Cu and of the degree of short-range order in alpha-brass at one composition and two temperatures. The purpose of this note is to call attention to a somewhat more accurate theory than that used by Birchenall and to extend the calculations to a wider range of temperatures and compositions as a means of testing its applicability. This is an example of the well-known general method of comparing measured thermo-dynamic functions of a system with those calculated from a microscopic model by means of statistical mechanics. In this case, mathematical approximations must be used which make difficult any decision about the validity of the model. Birchenall's statistical method resembles closely that called by Fowler and Guggenheim2 the "quasi-chemical" method which has been shown to lead in certain cases to results identical with those obtained by the method of Bethe.3 The quasi-chemical method has been extended by Takagi4 to give general formulae for the free energy of binary solid solutions based on several lattices at all compositions and temperatures. Specifically, he treats the four systems typified by: I. ß-brass; 2. a- brass; 3. AuCu3; 4. AuCu. When the temperature is so high that no long-range order exists, these formulae reduce to the same form for all lattice types, namely: [ ] Here the symbols have the following meanings: [F-Helmholtz free energy E-energy S-entropy k-the gas constant per molecule z-coordination number, (e.g. 12 in. a-brass). N-total number of atoms c-atomic fraction of A] VAA, VBB, VAB-energy per bond of the corresponding bonds log means log, throughout The superscript 0 denotes the thermo- dynamic function in the standard state, which has been chosen to be pure A or B with the same crystal structure as the solid solution. The quantity x is the ratio of the number of A-A bonds to the total number and for minimum F satisfies the equilibrium condition [ ] The free energy may also be written in terms of µA and µB, the chemical potentials or partial free energies per atom:

Jan 1, 1948

By H. Rush Spedden, A. M. Gaudin

IN the belief that a critical study of its operating problems might be a sound investment, the Cuban American Manganese Corporation initiated an ore-treatment research in cooperation with the Massachusetts Institute of Technology One of the early objectives of this research naturally became the relationship of the microscopy of the Cuban ores of the Corporation to their flotation treatment The operations in Cuba have already been described by F S Norcross, Jr 7 and the laboratory study of manganese oxide flotation goes back a number of years 4 Broadly speaking, the difficulties encountered in the flotation of manganese ores are that the consumption of reagents is extremely high, the concentrate contains more silica than is desirable and the tailing losses are relatively high An appreciable betterment on any of these scores would achieve a definite betterment in costs, quantity of minable ores, and quality of product The microscope study discussed in this paper was made on samples from the Quinto mine, from the Ponupo mine, and from mill products at various stages of passage of the ore through the mill The writers have had access to Company records and in particular to the petrographic studies made on thin sections of ore by the late Professors R J Colony and Philip Krieger, of Columbia University They acknowledge their debt to both of these men for the help derived from the reports Manganese oxides are black, friable, smudging It is therefore, very difficult to judge operations by inspection The mineralogy of manganese compounds seems to be confused, and the authors believe that many more minerals have been described than actually exist Much of this difficulty is due to the prevalence of the structural conditions that will be discussed further in this paper, namely, the porosity and the friability of the ores, and the extremely intimate association of minute manganifeous mineral crystals with impurities of various sorts By all odds the most important manganese mineral in Cuba is the one that in this paper is called "psilomelane " The name "psilomelane" has been used in so many different ways that the choice of it for this ore may not be approved by all However, it seems to be the best under the circumstances This mineral accounts for about 97 per cent of the manganese in the ores of the Quinto and Ponupo mines and in the mill feed The remaining odd 3 per cent consists mostly of pyrolusite together with minor amounts of other manganese oxide minerals DESCRIPTION OF PSILOMELANE Aggregate Structure In grains or lumps, psilomelane has a characteristic fibrous appearance and seems

Jan 1, 1942

By F. R. Hensel

PuRe silver and silver-lead alloys have been studied as to their suitability for bearing~.' A review of the properties of thallium and the silver-thallium constitutional diagram was made by the author to analyze the possibilities of silver-thallium compositions for antifriction materia1s. t The silver-rich end of the diagram as reported in the literatureg-" was found to be sketchy and it was necessary to carry out corisiderable experimental work to arrive at definite conclusions. Some of the results of this work are reported in this paper. Test Materials In the beginning of the work, only fused alloys were investigated. Later, research Table i.—Composition of Fused Silver-thallium Alloys Tested for Antifriction Properties Percentage Alloy No. of Thallium 1533...................... 0.48 1534.................... 1.06 a31 HT................... 2.04 231....................... 2.10 232 HT................... 3.83 Balance 232....................... 4.07 Silver 233 HT................... 5.86 a33....................... 6.38 a34....................... 9.84 a34 HT................... 10.07 was carried out on electroplating methods and diffusion processes. In preparing the fused alloyst care was taken to exhaust the toxic fumes caused by the thaillium content. The compositions of the series of fused alloys are listed in Table I. The silver-thallium alloys were melted in clay-graphite crucibles and cast into preheated steel molds of 3/4-in, diameter. In the cast condition, they showed a cored structure, as indicated by the micrographs of Figs. I to 3. The etching reagent used was a mixture of 2 grams K2Cr207, 8 C.C. H2S04, and IOO C.C. H20. The cored structure is unsatisfactory for the type of corrosion resistance required for bearing applications, and homogenizing experiments were carried out at various temperatures, the results of which are shown in Figs. 4 through 8. The alloys with a lower thallium concentration, which were heated for 2 hr. at 525°C show an almost completely homogenized solid solution type of structure. With higher thallium concentration, the homogenizing temperature was dropped to 475OC. to eliminate the formation of a liquid phase. It is evident that heating for 2 hr. at this temperature did not iesiilt iii complete elimination of the cored structure. As would be expected, cold-working of the cast structure is an expedient in establishing equilibrium conditions. The fine homogeneous grain structure shown in Fig. 7 corresponds to the cold-worked area under the Rockwell ball penetration when the hardness was taken before heat-treatment. A detailed structural study was made on a cast silver-thallium alloy containing 3.67 per cent thallium. Three micrographs (Figs. 9, 10 and 11) show the transition

Jan 1, 1946

By F. R. Hensel

PuRe silver and silver-lead alloys have been studied as to their suitability for bearing~.' A review of the properties of thallium and the silver-thallium constitutional diagram was made by the author to analyze the possibilities of silver-thallium compositions for antifriction materia1s. t The silver-rich end of the diagram as reported in the literatureg-" was found to be sketchy and it was necessary to carry out corisiderable experimental work to arrive at definite conclusions. Some of the results of this work are reported in this paper. Test Materials In the beginning of the work, only fused alloys were investigated. Later, research Table i.—Composition of Fused Silver-thallium Alloys Tested for Antifriction Properties Percentage Alloy No. of Thallium 1533...................... 0.48 1534.................... 1.06 a31 HT................... 2.04 231....................... 2.10 232 HT................... 3.83 Balance 232....................... 4.07 Silver 233 HT................... 5.86 a33....................... 6.38 a34....................... 9.84 a34 HT................... 10.07 was carried out on electroplating methods and diffusion processes. In preparing the fused alloyst care was taken to exhaust the toxic fumes caused by the thaillium content. The compositions of the series of fused alloys are listed in Table I. The silver-thallium alloys were melted in clay-graphite crucibles and cast into preheated steel molds of 3/4-in, diameter. In the cast condition, they showed a cored structure, as indicated by the micrographs of Figs. I to 3. The etching reagent used was a mixture of 2 grams K2Cr207, 8 C.C. H2S04, and IOO C.C. H20. The cored structure is unsatisfactory for the type of corrosion resistance required for bearing applications, and homogenizing experiments were carried out at various temperatures, the results of which are shown in Figs. 4 through 8. The alloys with a lower thallium concentration, which were heated for 2 hr. at 525°C show an almost completely homogenized solid solution type of structure. With higher thallium concentration, the homogenizing temperature was dropped to 475OC. to eliminate the formation of a liquid phase. It is evident that heating for 2 hr. at this temperature did not iesiilt iii complete elimination of the cored structure. As would be expected, cold-working of the cast structure is an expedient in establishing equilibrium conditions. The fine homogeneous grain structure shown in Fig. 7 corresponds to the cold-worked area under the Rockwell ball penetration when the hardness was taken before heat-treatment. A detailed structural study was made on a cast silver-thallium alloy containing 3.67 per cent thallium. Three micrographs (Figs. 9, 10 and 11) show the transition

Jan 1, 1946

By O. F. Kammerer, W. E. Miller, D. H. Gurinsky, J. Sadofsky, J. R. Weeks

Zirconium and titanium inhibit solution mass transfer of steels by liquid bismuth, mercury, and lead. It is shown that in bismuth and mercury, these adsorb on the surface of the steels and subsequently react with nitrogen and possibly carbon from the steels to form inert, adherent surface layers of ZrN, TiN, or TiN + Tic. Data are presented which describe the condition under which thase deposits form. These inhibitors decrease the solution rate of iron into bismuth, and require a higher supersaturation for precipitation of iron from bismuth. USE of the low-melting heavy metals (bismuth, lead, mercury, and their alloys) as coolants has been limited because solution mass transfer of steels occurs in these liquids; i. e., iron dissolves in the hot sections of the heat transfer circuit and deposits in the colder sections. The rate of solution of iron and the temperature coefficient of solubility are sufficiently great to cause complete or partial stoppage by the deposition in the coldest section of a closed circuit in finite time, even though the actual solubilities are extremely low. In the development of the mercury vapor turbine by the General Electric Co., Nerad and his associates1 discovered that the addition of as little as 1 ppm Ti or Zr to magnesium-deoxidized mercury reduced the mass transfer of ferrous alloys by mercury to a negligible amount. Reid2 reported that titanium was detected chemically on the surface of steels contacted with this mercury alloy in amounts varying from 2.0 to 2.6 mg per sq in., the greatest amount being found in the hottest portion of the circuit. Reid stated that the titanium forms the intermetallic compound Fe2Ti by reaction with iron on the surface of the steels. This compound was presumed to be highly insoluble in mercury. More recently, El-gert and Egan3 have reported a greater than 100-fold reduction in the rate of mass transfer of a 5 pet Cr steel by liquid bismuth upon the addition of titanium (in excess of 50 ppm) and magnesium (350 ppm) in the liquid metal, during experiments performed in thermal convection loops* over the temperature differential 700° to 615° C. Also, Shep-ard and his associates' have reported that the addition of titanium to liquid bismuth and Pb-Bi eutec-tic produced a marked decrease in the rates of solution of both iron and chromium from type 410 steel capsules under static conditions. This inhibiting effect increased with repeated reuse of the capsules. Tests performed in this laboratory under carefully controlled conditions have shown that the addition of zirconium and magnesium, or titanium and magnesium, to liquid bismuth or lead greatly reduces the rate of mass transfer of chromium alloy steels and carbon steels in thermal convection loops with a maximum temperature of 550°C.5-9 The present paper will review the data obtained to date at this laboratory on the behavior of iron and steels in contact with liquid bismuth alloys containing titanium or zirconium, and will attempt to explain the role of the above additives in reducing solution mass transfer. Reaction between the Zirconium or Titanium Dissolved In Liquid Bismuth and an Iron or Steel Surface Reaction between Zirconium Dissolved in Bismuth and the Surface of Pure Iron-—A small pure iron crucible (analyzed by the supplier to contain 0.8 ppm N was contacted with bismuth containing approximately 0.1 pet Mg and varying amounts of a radioactive zirconium tracer. The crucible was then inverted at the temperature of contact. The thin residual layer of adherent bismuth was dissolved in cold, concentrated nitric acid. The crucible surface and the solidified bismuth were then analyzed for radioactive zirconium. An analysis of the activity loss on the crucible surface and the weight loss of the crucible during the nitric acid treatment showed that the acid treatment removed the zirconium that had originally been dissolved in the adherent bismuth, but not any zirconium that may have reacted with the crucible surface. The crucible was then pickled in warm aqua regia to remove all surface activity, hydrogen-fired at 600°C, and recontacted with a new liquid alloy. The results of the experiments contacted 1 hr at 450°C show, Fig. 1, a Langmuir-type adsorption with an adsorption free energy of approximately 17 keal per g atom Zr.5 This deposit was estimated to contain 1 atom of zirconium for each 7 to 8 iron atoms on the crucible surface, assuming a surface roughness factor of the pickled crucibles to be five. Increasing the temperature to 520°C caused consi-

Jan 1, 1959

By Bernard Moore

THE last few decades have witnessed the introduction of many new nonmetallic mineral products and changes in the use of many of those already well known. Among these is diatomite, formerly employed as a mild abrasive and, at one time, as the absorbent material in dynamite. Now nearly 100,000 tons a year are mined and milled into such things as filter aids, cement admixtures, insulants, fillers, absorbents, cosmetics, cleansers, etc. Pumice, commonly regarded as only an abrasive, is now also employed as an insulant, as light-weight aggregate and as a concrete admixture. With increasing use of insulants, light-weight aggregates, and acoustic stuccos and plasters in the building trades, both these mate-rials should find increased application. Very large deposits occur in eastern Oregon and have been studied by the U. S. Geological Survey in cooperation with the Oregon State Mining Board.

Jan 1, 1934

By Leonard Greenburg, William B. Harris, Gustäv Werner

HAULAGE in tunneling operations generally has been done with electric locomotives. As a rule, on short hauls the source of electricity is a storage battery mounted on the locomotive, which, of course, must be removed and recharged periodically. Where the distance from the recharging point to the tunnel face is very long, and where loads are heavy, trolley-driven locomotives are used. Diesel engines have been used in mining and tunneling operations in Europe for a number of years. The recent reports of studies in Belgium1 and by the Bureau of Mines in this country2-4 have indicated the potentialities of this form of power for haulage, mucking, bulldozing and many other underground operations. The hazards attending the use of Diesel engines in more or less closed spaces have long been known. The exhaust constituents that may create a harmful or objectionable environment are carbon monoxide, oxides of nitrogen and sulphur, carbon dioxide, aldehydes and smoke. Lack of precise information regarding the concentration of these gases and the ventilation requirements to reduce them to safe levels has to some extent suppressed their general acceptance in tunneling and mining work. Not until the work of the Bureau of Mines referred to above, and certain experience gained in the construction of the Delaware Aqueduct,‡ has there been available the requisite information regarding the conditions under which their use may be permitted. This paper concerns itself with the successful operation of Diesel engines underground in the construction of certain parts of the Delaware Aqueduct, and describes the conditions under which Diesel engines have been found to operate with a minimum production of noxious gases. The test data reported were obtained during the operation of Diesel engines over a period of two years.* STUDIES BY THE NEW YORK STATE DEPARTMENT OF LABOR Exhaustive tests were made by the Division of Industrial Hygiene, of the composition of the exhaust gases given off by a Diesel engine mounted on. a test block. These tests showed that certain quantities of the gases are discharged from the exhaust. On the basis of these figures, preliminary requirements of design and control

Jan 1, 1942

By Andrew Fletcher

AS good health is the most important asset in life, the development of healthful conditions should be the one common meeting ground of agreement between management and labor. Health should not be a subject to be pulled apart, shoved around, or bargained about. Differences of opinion may exist in the procedure and techniques employed in approaching the goal of maintaining the health of workmen, and in the method of increasing the ultimate profit of the employer by improved working and living conditions. Such matters are doubtless appropriate subjects for discussions between the interested parties, but techniques are only tools. If an employer fails to remedy a hazard or a menace which contributes to poor working condlions, this constitutes a legitimate grievance. It should not be necessary, however, nor is it desirable that fundamentals of health maintenance become matters of collective bargaining, any more than should the principles of management and engineering. I have been especially concerned during the last few months with the propaganda in collective bargaining negotiations throughout the country for including in union contracts a given number of days of sick leave with pay. We all

Jan 1, 1946