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Jan 1, 1940

By F. C. Blake

THE test of the English Cupellation furnace should be so supported that the cupeller can change readily the elevation of the test, and at the same time watch the litharge channel. It is also important to raise or lower either side, independently of the other, in case of uneven wear of the side walls or of the breast. If the refined silver is poured from the test, it is much better to control the lowering of the test from the front than to raise the back by screws or a lever. In order to. enable the cupeller to manipulate the test with one hand, when the litharge is running, and to pour the refined silver from the test without aid, I have altered the common support to the .test, as shown in the accompanying drawing. The common method of supporting the test is by four screws, working in cross-bar nuts beneath the test. The points of the screws set into the test plate upon which the test rests. These screws are usually worked by pounding or pulling upon the heads, which may be either small pulleys or straight bars, as shown on the back screws in the drawing. The screws are also worked by turning a crank, which is

Jan 1, 1882

By A. Berthet

In the past two decades, of the successive steps leading from iron ore to finished steel, the production of liquid steel and its preparation for the casting operation has probably undergone the most drastic evolution. The reason for this is the development of oxygen converters (top blown and later on bottom blown) and UHP arc furnaces which are replacing the conventional processes such as the open hearth and basic Bessemer processes. These new processes have been great advances, but it would certainly be quite hazardous to assert that the situation will remain the same for the coming decades. In fact, with the advent of continuous steelmaking a new generation of processes has now arrived. The research and development programme at IRSID on continuous an a steelmaking began ten years ago has progressed systematically in the following stages : First a comparison was made on a small pilot scale of various techniques : for example, refining in a runner by top or bottom blowing, pulverizing the metal stream by oxygen, using the mixing effect of a vortex, etc. but for various reasons these processes proved unsatisfactory and were abandoned in favour of a method using the so -called "emulsion refining".

Jan 1, 1972

By H. D. Attra

The effects of phase behavior on reservoir economics is a function of both fluid composition and flow properties of the reservoir rock. In some operations such as gas injection into volatile crude-oil resertoirs, the stock-tank recovery derived from vaporization of the reservoir oil by the displacing gas can approach the recovery derived from the displacement mechanism. In other cases of gas-cycling reservoirs, the dry injected gas can effectively vaporize a retrograde liquid phase, allowing a substantial reduction in cycling pressure with no appreciable loss in recoverable liquids. Because of these effects, it is essential that phase behavior be considered in developing the economics of any secondary recovery program in which gas is the injected fluid. The inclusion of phase behavior in conventional calculation procedures has been retarded because of the complexity of the calculation and the large volume of laboratory data required. However, by applying high-speed computers and new laboratory techniques, the phase-behavior displacement calculation has been developed to economically include this basic fundamental of gas displacement. The calculation is performed by reducing the reservoir to a series of one-dimensional segments. Phase changes, saturation distributions and changing fluid properties are evaluated for each segment as a function of time. The relative volumes of equilibrium liquid and gas displaced from each segment are determined by a trial-and-error procedure to meet the requirements of phase equilibrium and two-phase flow. The produced fluids are flashed through conditions of surface separation approximating those in the field to obtain actual values for stock-tank liquid recovery and producing gas-oil ratios. Based on the results of successful field studies, the technique appears to have application to reservoirs producing under a nonmiscible gas-displacement mechanism and should substantially increase the reliability of this type of analysis when phase behavior is an important factor. Predicting reservoir performance under gas-injection operations involves three basic principles of reservoir engineering. First, a material balance exists between the displacing gas and the displaced reservoir fluid. Second, the oil and gas flow in relationship with the two-phase flow property of the reservoir rock; and third, phase equilibrium exists between the displacing gas and the native reservoir fluid. To illustrate these three principles, consider the one-dimensional reservoir shown in Fig. 1. The reservoir is divided into a series of segments representing a one-dimensional cross section between an injection area and a producing area. So represents the oil saturation, Cw represents the connate-water saturation and Sg represents the displacing gas saturation. The gas is moving into Segment 1 and the reservoir oil is being produced out of Segment N. Consider the case when gas has just moved into Segment 1 and the displacing gas-oil contact is at position a-a The volume of oil pushed out of Segment 1 is a function only of mobility and the two-phase flow properties of the reservoir rock, that is, Kg/Ko and µo/µg. Behind the front if the injected gas is foreign to the reservoir oil (a nonequilibrium gas), there will either be vaporization of the oil into the gas or condensation of the gas into the oil. In either case the net result is a mass transfer and a re-distribution of composition and liquid and gas saturation. If the displacement is at constant pressure and is continued, the gas moves into new segments, proceeding succesively into Segment 2, 3, etc. The total volume of oil produced from the reservoir

By R. A. Bergier

The Transactions of the Institute contain nothing, as yet, on the subject of pocket-compasses; and in the belief that American miners, explorers, geologists, and engineers will gladly welcome any infor mation about new forms of apparatus, simple in construction and adapted to rapid use, I offer a short description of an improved French combination pocket-compass, which, if once introduced into use, would seem likely to supersede similar instrumens of older pattern. The instrument in my possession I owe to the kindness of M. G. de.La Bouglise, of Paris. The frame of the compass is a double-bottomed box, 2 1/2 inches square and 9/16 of an inch high, made of white metal, and with its sur faces very carefully planed. The sides of the box make true right angles with each other. Two sides are parallel with, and two are normal to, the north and south line of the principal graduation. The bottom is accurately planed, so that the instrument will lie true on a plane surface. A glass, 2 3/8 inches in diameter, is set in the top plate. The graduation for the needle is engraved on the upper face of a ring, connected with the flat disk, in which the center-pin is in serted. Between this disk and the bottom of the box there is a hollow space a quarter of an inch deep. The needle is 1 7/8 inches in length, and can be balanced by means of a small sliding piece of metal. The graduation extends from 0° to 360°, reading from right to left. The stopping of the needle is effected by a screw, A, on the side of the box near the handle, H (Fig. 1). There is also a clinometer attachment, the graduation for which is engraved on the upper face of the silver-plated disk. The compass has two sights. The north sight, B, is a simple pin, a little more than an inch high, which, when not in use, is kept folded down, and is partially protected by the exterior sliding-plate, C. When raised for use, the sight is stopped in a vertical position by a projecting pin attached to the side of the box.. The south sight, D, is connected with the handle, H, and the sight and handle

Jan 1, 1890

By H. C. Chang, N. J. Grant

Creep of very coarse grained, high purity aluminum was studied at 400° to 1100°F with an initial stress range of 50 to 1200 psi. The process of boundary sliding and migration was studied. The driving force of boundary migration under creep conditions is shown to be a combination of strain energy migrationand surface energy. A theory is presented regarding the strainenergyrole the grain boundaries play under creep conditions. From this thetheory intercrystalline failure of commercial alloys can be explained. Also from this theory an optimum grain size should exist for good high temperature properties of high purity materials. IN the investigation of the creep of very coarse grained, high purity aluminum previously reported,' the cyclic nature of the process of grain boundary sliding and migration has been established by microscopic observation of the actual creep process as well as metallographically. It was also substantiated by measuring localized strains across the grain boundaries. In addition, it was shown how extensive subgrain and fold formation may result from boundary sliding and how the slid grain boundary may become sharply wavy as a result of subgrain formation. Since the publication of those results, additional information on the process of grain boundary sliding and migration has been obtained. It is the purpose of this paper to report on the direction and driving force of boundary sliding and migration, the effect of grain size, and the effect of temperature. Finally the effect of decreasing purity (alloys 2s and 3s) on the process of boundary sliding and migration is noted. From these results, an explanation is presented for the intercrystalline failure of alloys under creep conditions. The effects of grain size on the creep properties of impure and high purity materials are discussed in the same light. The experimental procedures and technique have been presented elsewhere.' It is only necessary to state how the 2s and 3s aluminum specimens are prepared. Machined specimens were first annealed at 600°F for about 12 hr. In order to produce a large grain size the specimens were then stretched 3 to 8 pct. The specimens were marked with reference marks, electropolished, annealed at 900°F for 24 hr and at 1150°F for 12 hr, and repolished. The grain size of 2s aluminum produced by this treatment is comparable to that of high purity aluminum in the direction of its width of the specimen, i.e., there are 2 to 4 grains across the width of the specimen. However, the grains of 2s aluminum are 3 to 10 times longer in the direction of the specimen axis. On the other hand, the grain size of coarse grained 3s aluminum ranges from 10 to 20 grains across the width of the specimen due to the treatment just outlined and therefore is much smaller than that of both high purity and 2s aluminum. As in 2s aluminum, the grains are about 3 to 10 times longer in the direction of the specimen axis than in the direction of the width of the specimen. The arrangements of the grains in 2s and 3s aluminum were generally irregular; therefore it was difficult to follow the course of the grain boundaries. Results Method of Presentation: In order to show the arrangement of the grains, especially the direction and positions of the grain boundaries, traces of the grain boundaries on the four surfaces of the specimens were unfolded and mapped out after macroetching. Figs. 1 and 2 show the structural development drawings of specimens P-3 and P-8 respectively. The two flat surfaces (of which the front one faces the microscope) and the round-edged surfaces will be called the "front surface" and "back surface" and

Jan 1, 1954

By C. W. Spencer, Che-Yu Li, R. J. Knight

The usual reaction product for the monotectic reaction in the Bi-Se system consists of rod -shaped particles of selenium-rich liquid embedded in a single crystal matrix of At certain crystallo-graphic orientations of the matrix with respect to the reaction interface, more complex shapes are as -sumed by the liquid particles. This reaction has been examined at different growth rates and relative crystallographic orientations of the matrix with respect to the reaction interface. The uhriation in auerage particle size of the liquid phase with reaction rate has been determined at one crystallograpIzic orientation of the matrix. On a plot of logarithm of average particle diameter vs logarithm of reaction rate, data points for crystals grown at rates of 10- to 1.0 cm per hr fall near a curve of slobe -0.4. MONOTECTIC reactions in binary alloy systems are reactions of the eutectic class in which, as the system is cooled through the three-phase reaction isotherm, one liquid phase (L) decomposes to a solid phase and another liquid phase (LII).' A partial phase diagram, as taken from Hansen, showing the monotectic reaction in the Bi-Se system is given in Fig. 1. This diagram specifies the monotectic point at 618°C and 72 at. pct Se, and the monotectic reaction products as the intermetallic Bi Se3 and a liquid (LII) which contains approximately 98 at. pct Se. At a lower temperature, 217°C, this liquid may undergo a eutectic reaction in which the reaction products are BizSe3 and crystalline selenium. However, under conditions of rapid cooling, or quenching, from above 217°C, this selenium-rich liquid may be partially retained to room temperature in an amorphous or glassy state. The intermetallic BizSe3 is rhombohedral, of the space group jm;' however, for convenience it is usually represented by a hexagonal struture. A pronounced plane of cleavage, which lies perpendicular to the main axis of the rhombohedral unit cell or parallel to the basal plane of the hexagonal cell, exists in the structure. The usual monotectic reaction product consists of rod-like particles of LII embedded in a single-crystal matrix of BizSe3, although at certain crystallographic orientations of the matrix BizSe3 other more complex shapes are assumed by LII. A similar rod-like, or cylindrical, morphology for the carbide phase has been reported by westbrook7 in the a Cr-Crz3Ce eutectic structure. In this paper the morphological characteristics of the LII particles, as retained to room temperature, have been examined under conditions of varying growth rate and crystallographic orientation of the matrix BizSe3 with respect to the growth direction. EXPERIMENTAL PROCEDURE Alloy specimens corresponding to the monotectic composition, 72 at. pct, or 50 w pct Se, were prepared from 99.999 pct pure bismuth and selenium obtained from the American Smelting and Refining Co. The two elements, corresponding to a total specimen weight of approximately 30 g, were encapsulated in 13 mm OD Vycor tubing under a vacuum of 5 x X mm of Hg. The capsules were suspended on a fine platinum wire in a Bridgman-type furnace which exhibited a temperature gradient of

Jan 1, 1963

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who registered at Institute headquarters during the period April 1 to 15. William B. McKinley, New York, N. Y Collier Cobb, Chapel Hill, N. C. C. W. Goodale, Butte, Mont. E. P. Fleming, Guayacan, Chile. D. C. Brown, San Luis Potosi, Mex. Albert Sauveur, Cambridge, Mass. W. H. Rettie, Yonkers, N. Y. H. M. La Follette, La Follette, Tenn. Mark B. Kerr, San Francisco, Cal. E. Fleming L'Engle, New York, N. Y. H. W. Turner, San Francisco, Cal. H. Garlichs, St. Louis, Mo. Frank M. Leland, Mackay, Idaho. Henry Hay, London, England. Sir Robert Hadfield, London, Eng. Edward J. Way announces that his agreement as consulting engineer in South Africa for the Anglo-French Exploration Co., Ltd., having terminated, he will engage in professional consulting work with headquarters at 135 Cullinan Buildings, Simmonds St., Johannesburg, South Africa.

Jan 5, 1914

By D. Hawington

HEALTH and safety in the mining and allied industries of the United States have unquestionably been progressing, particularly during the past three or four years, even though the progress has been anything but great in some branches of these industries. Statistical data to support this statement are readily available as to safety, but similar health data are unfortunately not available. In coal mining the rate of occurrence of fatal accidents per million tons of coal produced for the ten-year period 1911.20 inclusive was 4.27; this rate was 3.84 in 1930, .3.31 in 1931, 3.36 in 1932, and 2.69 (tentative) in 1933. In metal mining, the-rate of occurrence of fatal and- non-fatal injuries per .thousand 300-day workers (calculated) was 224.36 for- the same ten-year period. This fell slowly until after 1929 when it was 203.14, dropping to 170.78 in 1930, to 142.09 in 1931, to 138.46 in 1932, and to 155.13 in 1933. Here, again,-the real progress began in 1931 though the rate in 1930 was not particularly bad. For the same ten-year period, the rate of those killed and injured: in: quarrying per thousand 300-day workers (calculated)

Jan 1, 1935

James DouGlas, New York, N. Y. (communication to the Secretary*):—In my paper on the Conservation of Natural Resources, I referred to the slow replacement of bee-hive ovens by the by-product ovens as a most notable instance of waste. And I quoted from Mr. Parker's report for 1906 an explanation given by him in accounting for the small production of by-product coke. It was that the market for the by-products of the coke-ovens was so limited that some of the ovens constructed were out of operation. His report on the manufacture of coke in 1908' does not record an improvement, and attributes the strange fact that we alone, of all the industrial peoples, delay the adoption of this cardinal improvement from the continuance of the same almost inexplicable cause. To quote again from his report, he says (p. 241): "The year 1908 was not marked by any notable gain in the construction of byproduct coking plants, though some new work was done. There was a net increase

Jan 1, 1910

By T. D. Mueller

Many investigators have used the response of the "dimensionless aquifer" to a unit pressure drop or a unit fluid-withdrawal volume to calculate the performance of an aquifer in supplying water influx to an oil reservoir. In the past, these response functions have been calculated with the aid of the Laplace transform. With the advent of ultra highspeed digital computers, it becomes practical to solve for the response functions with finite-difference techniques. The computer method also permits extension of the dimensionless-aquifer concept to include the nonhomogeneous aquifer wherein the permeability and other properties vary as a function of the space co-ordinates. This paper gives results of calculating the response functions for a series of nonhomogeneous aquifers. Response functions are presented for both linear and radial aquifers whose thickness, permeability-viscosity ratio and porosity-compressibility vary. These functions are new and should prove useful to the petroleum engineer in analyzing the behavior of nonbomogeneous aquifers. Results are presented in the form of charts that can be easily used by the field engineer. INTRODUCTION Aquifers which surround many oil and gas reservoirs have the ability to supply water influx to such reservoirs as oil and gas are withdrawn. This water influx, called natural water drive, provides one of the most effective driving mechanisms for the production of oil and gas. In producing a reservoir, therefore, it behooves one to make the maximum use of natural water drive. To achieve the maximum use, the reservoir engineer must be able to predict the performance of an aquifer under a variety of production schemes that may be proposed for the reservoir. Unfortunately, the physical properties which dictate aquifer behavior often are known only within limits. Seldom do wells penetrate the porous strata of the aquifer. Even when they do, quantitative information regarding porosity, permeability and water compressibility is seldom available. It is known, however, that the water efflux from most aquifer systems is governed by a single, relatively simple, linear, partial differential equation. Also, the general physical location of the aquifer boundaries often are known. A technique originall proposed by Hurst1 and van Everdingen and Hurst2 has been found useful in analyzing reservoirs in this situation. The idea was later expanded by van Everdingen, Timmerman and McMahan3 to include the mathematical technique of least-squares fitting. This latter method will be referred to as the VTM method. The basic assumptions of the VTM method include the following. 1. The location of the physical boundaries of the aquifer are known. 2. The flow conditions at these physical bound-daries are also known. 3. The aquifer is homogeneous; e.g., thickness, permeability, water compressibility and porosity are constant throughout. In the VTM method, a material balance is made on the fluids entering and leaving the reservoir. In the balance equations, the water-influx term is represented as the product of the water influx from an arbitrarily-selected, dimensionless aquifer system times an unknown conversion number. This balance can be formed as many times as there are data points in the history of the reservoir. Each time, the conversion number can be evaluated. If the reservoir engineer has picked the correct dimensionless aquifer to represent the real aquifer, the conversion number remains constant for all balances that have been made over the history period. If such a situation occurs, the reservoir engineer can then predict the performance of the reservoir for any type of production scheme by using the function associated with that particular dimensionless system and the derived conversion number. These functions will be referred to as the response function of the aquifer. If the aquifer is nonhomogeneous (e.g., if the porosity, permeability, thickness, porosity, or

By WILFRED SYKES

IT is with particular pleasure that I welcome the members of the Open-hearth Conference of the I American Institute of Mining and Metallurgical Engineers to this meeting, as I feel this is one of the most useful activities of the Institute in the field of ferrous metallurgy. For the information of our other members I might say the Open-hearth Conference was organized by Mr. Reynders when he was president, and is made up of open-hearth superintendents and metallurgists. All the plants are invited to send representatives, and practically all do, with the exception of the U. S. Steel Corporation. It meets twice a year to discuss various problems in connection with the manufacture of steel, and its minutes are published for the benefit of those attending, the expense being defrayed by the participating companies. This conference, .1 believe, should be a model for activities in the other branches of the work covered by this Institute. It works, not by reading formal papers, which we all know is not a very satisfactory method to bring out the experience of others, but rather by a round-table method of discussion. The spirit of the meetings is such that each member feels perfectly free to state his experience, and he gets as much as he gives. A series of topics for, discussion is brought to the attention of the chairman and after one is exhausted the next point is taken up. In this way there is a real interchange of ideas and experiences which cannot fail l to be of the greatest benefit to those attending. That these meetings are beneficial is evidenced by the "continued growing attendance and lively discussions at these half-yearly meetings.

Jan 1, 1930

By Joseph G. Franzone, Alan K. Kuhn, Jerry J. Oliver

INTRODUCTION Tailings produced by many uranium milling operations consist of fine sands with some silt and slimes. When fine sandy materials are placed by hydraulic methods behind an impermeable dam, they are deposited in a loose state and some portion remains saturated. These saturated, loose fine sands are highly susceptible to liquefaction, the phenomenon in which a monotonic or cyclic disturbance causes excess pore water pressure and, concurrently, a total loss of strength in the sand. Once liquefied, the fine sand flows, causing collapse of supported structures. The potential for such a liquefaction failure was identified and successfully treated at Sohio Western Mining Company's L-Bar Uranium Operations near Seboyeta, New Mexico. The Sohio tailings dam is an earthfill starter dam with tailings raises constructed upstream of the starter dam crest. Beginning with the start of mill operations in 1976, tailings were deposited hydraulically in the impoundment behind the starter dam. As the tailings level approached the crest of the starter dam, beached tailings were excavated and placed in lifts by a dozer to form two raises above the crest of the starter dam. As the impoundment has gradually filled with tailings, the decant water pond level has risen. Correspondingly, the water level in the tailings dam, upstream of the chimney drain, has also risen. By August 1980, the phreatic surface was above the crest of the starter dam and stability analyses indicated that the tailings dam did not have the safety factor of 1.0, under static loading with liquefaction, implicit in the 1980 New Mexico State Engineer's requirements. The problem related directly to the high phreatic surface in the loose sandy tailings behind a dam structure that was not capable of resisting failure which might develop in liquefied tailings. Two methods of stability enhancement were considered for the Sohio dam. One method was reinforcement of the dam using a clay buttress placed against the downstream slope. The other method was installation of horizontal drains through the starter dam to drain decant water and lower the phreatic surface. Either method would increase the stability of the dam. However, the comparative analysis of the methods indicated that horizontal drainage offered significant advantages in cost and could provide a more direct remedy of the source of the problem, the saturated section of tailings. In addition, a drainage system would be more amenable to modification and more quickly installed than a buttress. On the other hand, a clay buttress could be more directly controlled, would involve routine earthwork, and has successful precedent. Therefore, the buttress approach would involve less risk. After weighing the advantages of both methods and the costs versus risks, the horizontal drainage approach was selected. Consequently, a horizontal pipe drain system was recommended and designed (D’Appolonia, 1981a). This paper describes the design and installation of the drainage system and its initial performance. PIPE DRAIN SYSTEM DESIGN Design Criteria and Parameters To increase the stability of the dam to acceptable levels, the drainage system had to lower the phreatic surface behind the dam to the level calculated to give a minimum safety factor of 1.0 under conditions of liquefaction. In addition, the system needed to be essentially self-operating, easy to maintain, and economical. To accomplish these objectives, the following design criteria were established: 1. The pipe drains must lower the phreatic surface at least 4.3 m (14 ft.) at the midpoint along the dam (the deepest section) and by proportionately smaller amounts toward the abutments to satisfy safety factor requirements.

Jan 1, 1982

By Svend Rordam

THE development of a cement that will resist the destructive action of sea water and other corrosive waters is a problem that has occupied cement chemists for the past one hundred years. It has been found that of the various salts that commonly occur in corrosive waters, sodium sulphate, magnesium sulphate and magnesium chloride are most destruc-tive to cement. Many investigations have been carried out in the United States, in Canada, and in Europe to solve the problem of what constitutes a sulphate-resistant cement, and during the past 10 years some of the findings give definite information in this respect. COMPOSITION OF CEMENT Portland cement is composed of four major compounds: 1. Tricalcium silicate 3CaO.Si02 (C3S) 2. Dicalcium silicate 2CaO.Si02 (C2S) 3. Tricalcium aluminate 3CaO.Al203 (C3A) 4. Tetracalcium aluminoferrite 4CaO.Al203.Fe203 (C4AF) The two calcium silicates are the main contributors of strength. The tricalcium aluminate contributes some to the early strength of the cement but has the least resistance of the four compounds toward the attack of sulphate waters. The tetracalcium aluminoferrite does not contribute very much to the strength, but is far more resistant to sulphate waters than the tricalcium aluminate. When hardened cement is exposed to water containing sodium or magnesium sulphates, these salts will react with the hydrated tricalcium aluminate in the cement and form compounds that will cause a swelling, disruption and crumbling of the hardened cement.

Jan 1, 1939

By B. W. Levinger

THE lattice parameter of the ß form of pure titanium has been measured at elevated temperature.', ' No attempt was made, however, to correct the parameter obtained to room temperature. In the course of phase diagram studies at Armour Research Foundation and elsewhere, the variation of ß-phase lattice parameter with composition has been established in a number of binary and ternary systems involving titanium. It was possible to extrapolate in these instances to 100 pct Ti to find the apparent lattice parameter of ß titanium at room temperature. Table I lists the results thus obtained. The suggested value for the lattice parameter of ß titanium is the average of the extrapolated values 3.276 ±0.003 kX. This suggested value gives an interatomic distance in ± titanium of 2.837 kX and hence a Goldschmidt atomic diameter (coordination number 12) of 2.925 kX. The latter agrees closely with the value of 2.93 given by Hume-Rothery." From the data of Adenstedt and coworkers' it was possible to determine by extrapolation the mean coefficient of linear expansion for /3 titanium in the range from room temperature to 1000°C. This value, 10.1x10-8 per degree C, compares with about 11x10-8 for a titanium in a similar range." It was thus possible to calculate the parameter at 900 °C. The value of 3.305 kX agrees well with 3.3065 given by Eppel-sheimer.' The majority of values reported in the literature7-', ' were given as Angstroms. In at least one case, ref. 8, it was shown that they actually represented kX units. The source of this confusion appears to be that a large number of tables of X-ray emission spectra list wavelengths as Angstroms and give values in kX units. The accepted conversion factor for kX units to Angstroms (10.' cm) is 1.00202. Thus the parameter of ß titanium suggested corresponds to 3.282A. References J. H. de Boer, W. G. Burgers, and J. D. Fast: Proc. Acad. Amsterdam (1936) 39, p. 515. 2D. S. Eppelsheimer and R. R. Penman: Nature (Dec. 2, 1950) 166, p. 960. 3 W. Hume-Rothery: The Structure of Metals and Alloys (1945) London. Inst. Metals. 4 H. K. Adenstedt, J. R. Pequignot, and J. M. Raymer: Trans. ASM (1952) 44, p. 990. 5 Gmelins Handbuch der Anorganischen Chemie. Titan, Verlag Chemie, Weinhein (1951). 8 P. Pietrokowsky and P. Duwez: Trans. AIME (1952) 194, p. 627; Journal of Metals (June 1952). 7 P. Duwez and J. L. Taylor: Trans. ASM (1952) 44. D. 495. 8 M. Hansen, E. L. Kamen, H. D. Kessler, and D. J. McPherson: Trans. AIME (1951) 191, p, 881; Journal of Metals (October 1951). 8 Unpublished Research, Armour Research Foundation.

Jan 1, 1954

By E. H. Crabtree

THE heavy-media separation plant at the Central mill of the Eagle-Picher Mining and Smelting Co., near Picher, Okla., was started in February 1939. Since that time twenty-four million tons of lead-zinc ore has been treated in the mill, of which approximately 70 pct has been treated by heavy-media separation. Until January 1945, galena concentrate from the flotation plant was used as the sink-float medium. At that time minus 100-mesh ferrosilicon was substituted for the galena, and its use has been continued. The purpose of this paper is to compare the operating results and the costs of operation of the two media. For the purpose of this comparison the period Jan. 1, 1943, to Jan. 29, 1945, has been taken to represent the operation using galena medium; the period Jan. 29, 1945, to Sept. 1, 1946, to represent the ferrosilicon medium. During the first of 'these periods about seven and one-half million tons was milled; during the latter, or ferrosilicon period, more than five million tons was milled. It is believed that these tonnages are large enough to give representative data. FLOWSHEET The Central mill has a capacity of 15,000 tons per day. Briefly, the treatment used consists of crushing the ore through 11/2-in. and wet-screening out the minus 3/16in. portion. The minus 1 1/2 plus 3/16in. washed product is treated by the heavy medium; the minus 3/16-in. product is deslimed and jigged. The heavy-media cone tailing is discarded and the cone .concentrate is recrushed and jigged for the production of a coarse lead concentrate. The cone concentrate, impoverished of lead, is then ground in ball mills and treated by differential flotation. The minus 3/16-in. jig product is similarly treated. HEAVY-MEDIA PLANT The heavy-media cone plant treating the minus 1 ½ plus 3/16-in. product consists of one open-top cone 20 ft in diameter by 20 ft deep, equipped with a central airlift. Concentrate is discharged from the top of the airlift to a 3 by 14-ft low-head Allis-Chalmers drainage screen. Medium drains back into the cone, from the first half of this screen. The last half of the screen is provided with washing sprays for further removal of medium. Cone tailing is similarly drained and washed. Undersize from the washing screen is thickened and then cleaned in the medium-cleaning plant. When galena was used as a medium, cleaning was done in Fagergren and Denver flotation machines. The ferrosilicon is cleaned in three 36-in. and one 24-in. Crockett magnetic separators. A flowsheet of the cone plant is shown in Fig 1.

Jan 1, 1947

By P. R. Sperry

Aluminum alloy 3S was examined to determine the relationship between the applicable phase diagram and the microstructures produced under conditions tending toward non-equilibrium as well as equilibrium. The only phases present in the alloy were aluminum, (Mn,Fe)A16, aAI(Mn,Fe)Si, and silicon. It was found that the alloy behaved essentially as though it belonged to the Al-Mn-Si system. The effects of various solidification rates and of various homogenization treatments were studied. Particular attention was given to a nonuniform precipitate distribution which reflected the solute distribution in the cast aluminum solid solution. Some possible explanations for the solute distribution based on characteristics of the Al-Mn-Si or AI-Mn systems were discussed. ALUMINUM alloy 3s (aluminum plus 1.25 pct Mn) is one of the oldest and the most widely used of the wrought aluminum alloys. In spite of this fact, there are some aspects of the metallography of 3s which have not been revealed or which have not been brought to the attention of the metallurgist working with the alloy. The purpose of this investigation was to demonstrate in general how some of the fundamentals of equilibrium phase diagrams may be applied to the study of an alloy and to show specifically the origin of certain metal-lographic features of aluminum alloy 3s. It is hoped that this information can serve as a basis for solving specific problems relating microstructure to such things as mechanical properties, recrystallization, grain growth, and surface finish. Literature Survey Considering that alloy 3s contains only one alloying addition, manganese, it seems reasonable that it would have characteristics pertaining to the A1-Mn system. However, those characteristics might well be altered by the impurities in the commercial alloy, especially iron and silicon. Therefore, not only the simple binary but also more complex systems had to be reviewed. One characteristic of the A1-Mn system worthy of mention is its sluggishness, which leads to conflicting solubility data1,'2 and makes it relatively easy to supersaturate the solid solution and shift the eutectic composition during rapid solidification.3'4 Another characteristic is the strong influence which small amounts of impurities, especially iron, exert in lowering the solid solubility of manganese. Undissolved manganese is ordinarily present in an intermetallic phase, MnAl,, having an orthorhombic crystal structure. A metastable precipitating phase designated as "G" has been reported but small amounts of iron and silicon suppress this phase entirely." Raynor has established that MnA1, can dissolve a considerable amount of iron by a substitution of iron for manganese atoms up to 50 atomic pct.'" Consequently, in the Al-Mn-Fe liquidus diagram, the eutectic valley separating the primary aluminum and (Mn,Fe)Al, fields is fairly close to a constant Mn + Fe content." This is an important consideration in regulating the composition of 3s and also other aluminum alloys with high manganese additions."

Jan 1, 1956

By T. W. Guy

DURING recent years, tremendous strides have been made in the economical use of coal. This has resulted in, and to some extent has been a result of, making the fuel specifications more and more rigid. For this reason, all producers have found it necessary to improve their preparation materially, both as to sizing and the elimination of impurities, either by more effective preparation underground or at the tipple and cleaning plant, or both. This cause and its effect in all producing fields seem likely to continue for several years-at least. The splendid inherent qualities of the Pocahontas and New River coals are known all over the world, but their good reputation is only partly due to inherent qualities, and to natural conditions which generally favor loading coal comparatively free from impurities; it is due in large measure to the care and skill used, either with or without the aid of mechanical devices, to ship products consistently low in ash. The first coal from the West Virginia smokeless fields was mined and shipped near Quinnimont, on New River, in 1871, while the first shipments from the Pocahontas field were in 1883. The development of both fields progressed rapidly. At first activities followed the main lines of the Chesapeake & Ohio and Norfolk & Western railroads, and were extended later as branch lines were built from these roads. The Virginian R. R., about 1907, opened up the Winding Gulf territory, which has since become a large producer of smokeless coals from the Pocahontas and the New River measures.

Jan 1, 1931

By N. S. Stoloff, R. G. Davies

A study has been made of the efject oj different dislocation-precipitate interactions upon the temperature dependence of the flow stress of aged Ni-14 at. pct A1 alloy. It is observed that when the dislocations bow between widely spaced (-20004 coherent Ni3Al particles the flow stress decreases with increasing temperature in the normal way. However, when the dislocations cut closely spaced (-5004 particles the flow stress is independent of temperature from -100 to 600°C, due to a balance between softening of the matrix and an increase in strength of the particles with increasing temperature. The retention of strength at high tempera-tures of commercial nickel-base alloys, which are strengthened by the precipitation of a phase based upon Ni3Al, is thought to be due to the unusual strength properties of Ni3Al. The flow stress of Ni3Al increases continuous1y from -196"C to a maximum at -600"C. It is concluded from a series of thermal-mechanical tests that the sevenfold increase in flow stress over this temperature interval is due to a lattice effect and is not diffusion-controlled. The flow stress of precipitation- or dispersion-hardened materials depends on the resistance to dislocation motion within the matrix and the extra energy required for dislocations to bow between or to cut particles. If the dislocations bow between the particles or if the strength of the cut particles is constant with temperature, then the flow stress of the precipitation-hardened alloy must decrease with increasing temperature due at least to the decrease in elastic modulus of the material. There will be softening also from thermally activated cross-slip or climb, offering an additional degree of freedom for dislocations to avoid particles. For example, in the case of nickel containing a dispersion of thoria,' which most probably deforms by dislocations bowing between particles, the flow stress decreases by about 50 pct between 25" and 650°C. In A1-Cu alloys2 aged to produce the 8" precipitate, dislocations cut the particles, and the flow stress decreases by about 20 pct between -269" and 25°C. However, many commercial high-temperature nickel-base alloys, for example Inconel-X and Udimet-700, exhibit little or no decrease in flow stress with increasing temperature up to about 700°C. A characteristic feature of these alloys is that they are strengthened by the precipitation of a phase based upon Ni3A1. Guard and westbrook4 and flinn' have shown that Ni3Al (and alloys in which a third element such as molybdenum or iron is substituted for part of the aluminum) is unusual in that the hardness and flow stress increase with temperature to a maximum at about 600°C. For the flow stress of a precipitation-hardened alloy to be independent of temperature we propose that the particles must be cut by dislocations moving through the matrix and that the strength of the particle must increase with increasing temperature. Theories of precipitation hardening do not take into account the flow stress of the dispersed particles that are cut during deformation; the only dissipative process usually considered7 is the creation of interface within the particle and between the precipitate and matrix. The purpose of the present investigation has been to study in detail the temperature dependence of the flow stress of a nickel-base alloy strengthened by the precipitation of Ni3Al in two structural conditions such that when deformation occurs it does so by dislocations a) bowing between the particles and b) cutting the particles, respectively. A simple binary Ni-14 at. pct A1 alloy was chosen because considerable information is already available for this system concerning phase equilibria and precipitation reactions and rates.' Dislocation-precipitate interactions in the binary alloy should be similar to those in the more complex commercial alloys. In addition, the mechanical and physical properties of NisAl were studied in detail in the hope of elucidating the mechanism by which the strength increases with increasing temperature up to 600°C. EXPERIMENTAL PROCEDURE For the study of the effect of precipitation of Ni3A1 upon the temperature dependence of the flow stress, an alloy containing 14 at. pct A1 was utilized; a Ni-8 at. pct A1 solid-solution alloy was employed as a comparison material. Vacuum-cast ingots were hot-rolled at 1000°C and cylindrical compression samples, 0.20 in. diam by 0.40 in. high, were prepared from the 1/4-in.-diam rod. Specimens were recrystallized and solution-treated at 1000°C for 1/2 hr and then water-quenched. A preliminary study revealed that, when the Ni-14 at. pct A1 alloy was aged for 1 hr at 700°C, significant precipitation hardening was obtained, and that the structure was free from grain boundary discontinuous precipitation; an overaged condition was produced by annealing the aged specimens at 850°C for 1 hr. To circumvent the difficulties involved in the hot rolling and swaging of Ni3A1, compression samples,

Jan 1, 1965

By D. R. George

Preliminary research has identified several organic and aqueous solutions that are effective absorbents for SO, from simulated smelter gas containing 0.3 to 2% SO2. These SO2 loaded solutions are also compatible to the reaction of H2S and SO2 to precipitate a readily filtered elemental sulfur. The economic removal of SO2 and production of elemental sulfur from stack gases discharged by base- metal smelters is a challenging goal. The magnitude of this task is illustrated by the estimate that about 3.5 million tons of SO2 are discharged to the atmosphere by smelters annually in the U.S. The SO2 concentration of the gases ranges from about 0.5 to more than 3%. As the sulfur content of SO2 is 50% a potential production of 1,750,000 tons of sulfur per year is indicated.

Jan 1, 1970