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By Walter Miller

Any annual review of engineering progress in petroleum refining must of necessity include many features mentioned in earlier reviews. Advances do not spring mushroom fashion to wide acceptance overnight, but rather resemble rolling snowballs, gathering size and velocity as they progress. The new ideas of one year develop through the course of scattered adoption and testing during following years, to be ultimately discarded or to become an integral part of refinery engineering and operation. Polymerization and Cracking As an illustration, the publicity given to the polymerization and cracking of petroleum gases during the year has given many the impression that this is a new art. But patent and technical literature have disclosed active work on the problem dating back a decade or more and a unit capable of making 100 bbl. a day of polymer gasoline was constructed as early as 1930. Important strides have been made during 1935 looking to the more general commercialization of available processes, and some four important groups are furthering this work. In addition to the production of liquid products for inclusion as a constituent of commercial motor fuel, polymerization has also been a factor leading to the installation of a plant at the Houston refinery of The Shell Petroleum Corporation for manufacturing isooctane for aviation use, by making available dibutylene for catalytic hydrogenation Polymerization is not confined to unsaturated hydrocarbon gases as a source of raw material, and has been extended to include a preliminary decomposition of normal saturated gases under suitable heat and pressure conditions into the unsaturated types, which can then be used as raw material for the polymerization process. Thus there is opened up the possibility of eventually using large quantities of natural gas in the manufacture of high-grade motor fuels, although the early commercial growth will be largely on cracking still gases for economic reasons. Such utilization will result in a somewhat lowered drain on crude-oil reserves and a partial elimination of the

Jan 1, 1936

By Claus G. Goetzel

Pressing of powdered metal parts is best done in the direction of the shortest extension of the piece, to avoid too great a loss of pressing force through internal iriction. As long as curved surfaces, re-cessej, or offsets occur only parallel to this shortest axis of pressure, no special difficulties arise: the cross sections, perpendicular to the pressure, do not vary, nor does the shape of the parts change during compression except for a gradually reduced thickness (Fig. IA). The problem becomes more dificult, however, when the curved surfaces or recesses are perpendicular to the shortest axis of the part (Fig. IB) Two processes for molding uniformly dense parts with complicated shapes from powdered metals are described in detail in this paper. Both can be employed successfully by those trained in the art. The first refers to curved parts; the second is especially adapted to parts having one or more recesses or steps. Both methods, as set forth here, are applied under the condition that presents the more difficult problem. For clarity, before description of the two practical methods, the variable factors in molding powdered metal parts will be reviewed, then an idealized procedure will be considered briefly. Variable Factors in Molding Powdered Metal Parts Compression Ratio Compression ratio is defined as the proportion of the final relative density of the compact to the apparent density of the powder. For iron powder of an apparent density of 3.0, for example, a compression ratio of 2 1/2:1 would be required to produce a compressed compact of 7.5 density; whereas for another iron powder having an apparent density of only 1.5, a compression ratio of 5:1 would be required to produce the same density. The lower the powder's apparent density, the greater must be the compression ratio for pressing compacts of high density.

Jan 1, 1946

By Claus G. Goetzel

Pressing of powdered metal parts is best done in the direction of the shortest extension of the piece, to avoid too great a loss of pressing force through internal iriction. As long as curved surfaces, re-cessej, or offsets occur only parallel to this shortest axis of pressure, no special difficulties arise: the cross sections, perpendicular to the pressure, do not vary, nor does the shape of the parts change during compression except for a gradually reduced thickness (Fig. IA). The problem becomes more dificult, however, when the curved surfaces or recesses are perpendicular to the shortest axis of the part (Fig. IB) Two processes for molding uniformly dense parts with complicated shapes from powdered metals are described in detail in this paper. Both can be employed successfully by those trained in the art. The first refers to curved parts; the second is especially adapted to parts having one or more recesses or steps. Both methods, as set forth here, are applied under the condition that presents the more difficult problem. For clarity, before description of the two practical methods, the variable factors in molding powdered metal parts will be reviewed, then an idealized procedure will be considered briefly. Variable Factors in Molding Powdered Metal Parts Compression Ratio Compression ratio is defined as the proportion of the final relative density of the compact to the apparent density of the powder. For iron powder of an apparent density of 3.0, for example, a compression ratio of 2 1/2:1 would be required to produce a compressed compact of 7.5 density; whereas for another iron powder having an apparent density of only 1.5, a compression ratio of 5:1 would be required to produce the same density. The lower the powder's apparent density, the greater must be the compression ratio for pressing compacts of high density.

Jan 1, 1946

By C. Wachmann

The theory presented ill this paper makes possible examination of the phenomenological aspect of secondary oil recovery by alcohol flooding. Limitutions of the theory are contingent on three primary assumptions: (1) chemical equilibrium, (2) no fingering, and (5) no dispersion. The second assumption implies one-dimensional flow. In a geometric sense the theory extends the Buckley-Leverett construction to systems of two slightly miscible fluids and to systems of three components. This is made possible by considering single-phase fluids to be made up two phases, namely of an excess of one phase and a negative amount of the other phase. The procedure is discussed in the paper. The theory also permits direct determination of the relationship between the aqueous phase saturation and the concentration of water in the aqueous phase in a zone of variable composition. The velocity of planes of constant water concentration and of constant saturation can be computted likewise and the existence of saturation discontinuities inferred. Consequently the behavior of such a Zone, which may exist at some time between a displaced and a displacing fluid, May be determined. mathematical details are given in Appendices. Problems of experimental verification are pointed out on the basis of a supporting experiment. Implications of the theory and effects of violations of primary assumptions are discussed briefly. The major conclusion is that, if the primary assumptions are met, with pure alcohol and alcohol-rich .slugs piston-like displacement of oil and water is possible. INTRODUCTION The recovery of oil from porous media by alcohol displacement has been studied for several years. Extensive experimental investigations into alcohol flooding have been carried out in the laboratory although little has been done in the field. A large amount of practical information is available, the extent being indicated by the first three papers cited 1-3 and their respecrive bibliographies. This has permitted the Formulation of inferential theories. A more analytical approach in which theories are developed primarily by reasoning from known physical principles and relationships has, however, lagged behind. In fact, an analytically derived theory of alcohol displacement has not been available. The theory presented in this paper on oil and water displacement by alcohol from a porous medium is a result of the analytical approach. The theory is idealized, as certain assumptions had to be made to make the mathematics tractable and reduce complexity of argument. In particular, major assuptions concerning conditions of equilibrium, interfacial stability, longitudinal mixing, etc., led to the exclusion of fingering, for example, from all considerations. In many laboratory experiments reported in the literature fingering could not be avoided. There is, therefore, disagreement between theories based on experimental evidence available and the analytically derived theory presented here. This theory presented is based on known physical data and makes use of the Buckley-Leverett construction and its suggested extension. The mathematical derivation of the theory is given in Appendices. Three examples relevant to alcohol displacement are discussed to explain the use of this theory: (1) system of two immiscible fluids (the Buckley-Leverett case); (2) system of two slightly miscible fluids involving an extension of the Buckley-Leverett construction; and (3) system of three components, including injection of pure alcohol or alcohol-rich fluid as a special case, which involves a more general extension of the Buckley-Leverett construction. In these discussions strict assumptions were made to impose equilibrium conditions and exclude mixing and fingering. Effects of relaxing these assumptions and consequent extensions of the theory are indicated. The complexity of the alcohol displacement process makes experimental verification of the theory essential. Some relevant evidence is offered in this paper.

Jan 1, 1965

By J. T. Ryan

IN making a comparison of mine inspection methods in Europe and the United States, it is necessary to have some basis to start from, which makes this subject rather difficult, as such methods are governed largely by the authority given the inspector by the mining laws. In the United States there are 31 coal producing states and territories and 32 different mining laws under which inspectors operate, as one state-Pennsylvania-has both a bituminous and an anthracite code. Some of these codes are distinctly coal mining codes; others are essentially coal mining but apply also to other mines; several codes are sub-divided referring partly to coal mines and partly to other mines, and a few codes are mainly metal mining but apply in part to coal mining. Having all these different codes in the United States and the departments organized in a variety of different ways, there is of necessity a great difference in inspection methods in this country.

Jan 1, 1926

By J. B. Fletcher

The Miami mine first started operations in 1910. For convenience, the history of the orebody can be divided into the following categories (Fig. 1): 1) 1910 to 1925: 24.4 million tons of high grade ore, mined by top slicing, sublevel caving, etc. 2) 1926 to 1954: 102 million tons of low grade ore, mined by block caving.

Jan 1, 1961

Succession of Minerals and Temperatures of Formation in Ore Deposits of Magmatic Affiliations BY WALDEMAR LINDGREN (Tech Pub 713 10,000 words ) The paper presents data accepted by many geochemists and geologists regarding the succession of minerals and the temperatures of formation in ore deposits affiliated with igneous rocks It also presents the individual views of the author on the composition of the solutions that were active and on the mode of deposition He does not regard these views as speculations or hypotheses but as forming a well motivated and con¬sistent theory It is not certain, however, that all investigators will subscribe to them The mining engineer may not always be interested in the field of stability and tempera¬ture of origin in the mineralogy of ore deposits, but he certainly is interested in the succession of minerals because this has a definite bearing on the understanding of the ores and on the best processes of extraction The author, therefore, summarizes in plain language the principal features of succession as shown in metallic ores

Jan 1, 1937

By J. J. Gilman

Rates of prisnzatic plastic glide ( {1010}<2110>) in pure Cd crystals have been measured at temperatures from 158° to 276°C. The glide rate is proportional to the 2.75 power of the applied shear-stress. The activation energy is 29.2 kcal per mol. It is suggested that the rates of prismatic glide in Cd and Zn crystals are determined by the strengths of the atomic bonds across the prism planes. ALTHOUGH zinc and cadmium crystals both have hexagonal structures with nearly the same c/o ratios, their mechanical behaviors are quite different. Whereas zinc becomes quite brittle below room temperature, and cleaves readily on (0001) planes, cadmium is very ductile even at 4.2°K, and cannot be cleaved at any temperature. As part of a search for the explanation of this difference in behavior, a study has been made of prismatic glide in cadmium. It complements a previous study of the same phenomenon in zinc.1 The primary glide plane in cadmium is the basal (0001) plane, and the primary glide direction is the direction of atomic close-packing <2110>. However, if a tensile stress is applied parallel to the basal plane, then the shear stress on the basal plane equals zero so basal glide cannot occur. At low temperatures, deformation by twinning occurs; but at high temperatures, it has been found in this study that gliding on prismatic planes (1010) occurs in the close-packed direction. This is completely analogous with the case of zinc, except that lower temperatures are required. EXPERIMENTAL The experiments were done in nearly the same way as for zinc.&apos; Therefore, only the differences in the two sets of experiments will be described here; for other details the reader is referred to the previous paper. Crystals 6 by 6 mm sq were used that were grown from "Super Purity" 99.999 + pct Cd purchased from the New Jersey Zinc Co. The crystals were grown with their basal planes parallel to both the rod axis and one of the flat sides of the square cross section, A close-packed direction in the basal plane was oriented parallel to the rod axis. Gage sections were carefully machined into the crystals, and the surface damage caused by machining was removed with the same chemical polishing reagent as had been used for zinc. Thus, specimens of the same form and size as the previous zinc ones were produced. The crystals were heated to the test temperatures in a silicone oil bath (fused salts were tried first, but they reacted badly with the cadmium). An Instron tensile-testing machine was used for applying stresses to the crystals at various constant strain-rates. RESULTS The general behavior of cadmium crystals is much the same as for zinc. Only the constants that measure specific properties are different. Just as

Jan 1, 1962

By D. Turnbull, H. N. Treaftis

Precipitation of tin from Pb-Sn alloys (lead-rich) occurs by the nucleation and growth of hemispherical cells which consist of tin lomelloe interspersed in the depleted solid solution. Nucleation and growth of these cells and the tin interlamellar spacing at various compositions and temperatures have been investigated. The interlamellar spacing increases approximately as the reciprocal of the logarithm of the supersaturation ratio. For constant initial tin concentration the concentration of cell nuclei increases with decreasing temperature to a limiting temperature-independent value. The kinetic results support the view that the cell growth rote is governed by the diffusion of tin along the cell boundary. In the main, the results confirm the authors&apos; earlier deductions, drawn from resistometric and calorimetric data, about the precipitation mechonism. IT has been shown1, 2 that tin (ß) precipitates from lead-rich (a) PbSn solutions by the nucleation and growth of cells (cellular or discontinuous precipitation). These cells consist of tin lamellae, with a spacing 1, interspersed in a depleted a solution. Reorientation of a also accompanies cell growth. The kinetics of cellular precipitation of tin from lead have been measured by resistometric2, 3 and ca1orimetric1, 3 techniques. The time-transformation isotherms (t equals time; x, volume fraction of specimen transformed) of the initial rapid precipitation, which drains about 60 pet of the tin from solution, have been described by a kinetic law having the form x = 1 —exp (—bt n) [I] where n usually has the value 3.0. It was shown" that this law and the other kinetic facts can be explained satisfactorily if it is assumed that the cells grow at a constant rate and that all the cells nucleate in a time negligible in comparison with the period of cell growth before impingement. Thus, for hemispherical cells b = (2/3)pNG3 [21 where G is the rate of cell growth in cm per sec, and N is the number of cell nuclei per unit volume. The rapid rate of cell growth at low temperatures can be accounted for"&apos; if it is assumed that the dissolved tin drains to the lamellae edges by diffusion along the sweeping cell boundary rather than by diffusion through the a crystal (volume diffusion). For cell growth governed by cell boundary diffusion it was shown, approximately G=2(X° - X° / X° ) DBA / l2 where A equals the thickness of the cell boundary; D R, the coefficient of diffusion of tin atoms within the boundary; and X° and X, are the atom fractions of tin in the supersaturated and saturated solutions, respectively. Zener8 had already shown that, where

Jan 1, 1959

By B. T. Wykoff

This paper describes an important function of mining in Southeast Missouri. The practice is a necessary procedure to prevent disintegration of the pillars. Although the technique is peculiar to this district, it might have application in other mines using room and pillar method. CONSIDERING the subject alone, this paper would cover only a mechanical treatise of pillar roping. Because the St. Joseph Lead Co. originated the practice, it is proper to give a short introduction to the company. It is also proper to describe pillars and discuss their purpose to justify expending large sums of money to preserve them after the surrounding area has been thoroughly mined. Because the St. Joseph Lead Co. originated the practice of back pinning with wedge bolts, patch plates and channel irons, and the pouring of substitute pillars of concrete, these too, are mentioned. The Southeast Missouri Division of the St. Joseph Lead Co. is the largest lead producer in the United States. About 95 pct of the present producing mines are in St. Francois County, which begins 60 miles south of St. Louis. The entire lead ore production of this county, at the present time, is mined and milled by this company, treatment plant capacity being about 22,000 tons per day. This area is also the oldest, lead having been mined at Mine La Motte, in Madison County, in 1723. Estimated production of all the various companies that have mined here is about 7,000,000 short tons of pig lead. Method of Mining The lead occurs in the ore as galena. Galena is found either in the form of disseminated or solid streaks, of varying thickness. Ore stratum is the Bonne Terre dolomite, which is about 350 ft thick, but almost all the ore is in the lower 100 ft. Ore is mined by room and pillar method in open stopes. These stopes vary in height from 7 ft to 200 ft, depending on the thickness of the pay ore in that spot. Back, or roof, is supported entirely by pillars. In a majority of stopes, after the loose scales are mined down, the back has remained solid for many years (fig. 1). Under ideal conditions pillars are spaced to form an equilateral triangle and are as small and as far apart as the height of the stope and the character of the back will permit. They vary in diameter from 10 ft to 50 ft and are from 18 ft to 50 ft apart, measured from the outer edges. In general, the pillars are approximately 12 ft in diameter, and 25 ft apart. The spacing is very uncertain because of the vagaries of the ore trend, the desire to better support breaks in the back, and the attempt to spot out the thinner ore by not placing one in the core of the ore body. Use of Structural Steel Channels In stopes where the back is bad because the overlying formations are thin with wet, weak and shaly

Jan 1, 1951

By B. T. Wykoff

This paper describes an important function of mining in Southeast Missouri. The practice is a necessary procedure to prevent disintegration of the pillars. Although the technique is peculiar to this district, it might have application in other mines using room and pillar method. CONSIDERING the subject alone, this paper would cover only a mechanical treatise of pillar roping. Because the St. Joseph Lead Co. originated the practice, it is proper to give a short introduction to the company. It is also proper to describe pillars and discuss their purpose to justify expending large sums of money to preserve them after the surrounding area has been thoroughly mined. Because the St. Joseph Lead Co. originated the practice of back pinning with wedge bolts, patch plates and channel irons, and the pouring of substitute pillars of concrete, these too, are mentioned. The Southeast Missouri Division of the St. Joseph Lead Co. is the largest lead producer in the United States. About 95 pct of the present producing mines are in St. Francois County, which begins 60 miles south of St. Louis. The entire lead ore production of this county, at the present time, is mined and milled by this company, treatment plant capacity being about 22,000 tons per day. This area is also the oldest, lead having been mined at Mine La Motte, in Madison County, in 1723. Estimated production of all the various companies that have mined here is about 7,000,000 short tons of pig lead. Method of Mining The lead occurs in the ore as galena. Galena is found either in the form of disseminated or solid streaks, of varying thickness. Ore stratum is the Bonne Terre dolomite, which is about 350 ft thick, but almost all the ore is in the lower 100 ft. Ore is mined by room and pillar method in open stopes. These stopes vary in height from 7 ft to 200 ft, depending on the thickness of the pay ore in that spot. Back, or roof, is supported entirely by pillars. In a majority of stopes, after the loose scales are mined down, the back has remained solid for many years (fig. 1). Under ideal conditions pillars are spaced to form an equilateral triangle and are as small and as far apart as the height of the stope and the character of the back will permit. They vary in diameter from 10 ft to 50 ft and are from 18 ft to 50 ft apart, measured from the outer edges. In general, the pillars are approximately 12 ft in diameter, and 25 ft apart. The spacing is very uncertain because of the vagaries of the ore trend, the desire to better support breaks in the back, and the attempt to spot out the thinner ore by not placing one in the core of the ore body. Use of Structural Steel Channels In stopes where the back is bad because the overlying formations are thin with wet, weak and shaly

Jan 1, 1951

Joseph Esrey Johnson, Jr., had already achieved rare distinction as an able metallurgist, clear thinker, brilliant author, and wise consulting engineer to bankers and operators; he had achieved the essentials of a great career when dcath cut short his activities on Apr. 4, 1919, in the forty-ninth year of his age. He belonged to a family of iron blast-furnace men and mine managers. His father, Major J. E. Johnson, after serving with distinction in the Army of the North, identified himself with the iron mines and blast furnace at Longdale, Va., with which he was connected during almost his entire business life. It is significant, that, during those troublous times of reconstruction in the South, he enjoyed always the affection and respect of his neighbors and associates alike. From him his son obtained not only a thorough training in blast-furnace practice and iron mining, but great personal courage and force of character. His mother, who survives both her husband and sons, possesses rare intellectuality, humor and a tenderness and human sympathy which those who were privileged to know well J. E. Johnson, Jr., recognized beneath his exterior of aggressiveness and will power. In a recently published analysis of the qualities which characterize the world&apos;s great men, three traits stand out preeminently; viz., independence, courage, and intellectuality. Each of these characteristics J. E. Johnson, Jr., possessed in extraordinary degree. His early education was obtained under a private tutor at Longdale, and this circumstance probably enhanced a natural tendency to independence of character and individuality which, however, under the control of his unusual power of straight thinking and clear analysis never allowed him to go far astray. It has been said of him that if once he set his mind to a problem, however knotty, he scored a bull&apos;s-eye before the subject was dropped. His manner of attacking a subject involved first mastering the details of the available knowledge; then, putting this acquired information to one side, with an untrammeled mind blazing out a path of his own, so clear, so well-defined, and expressed in such simple terms that he illuminated the whole subject without distorting the original data or discussion. His two books, "Blast-furnace Construction in America" and "The Principles, Operation, and Products of the Blast Furnace, "on the iron blast furnace together form the most comprehensive, the most enlightening, and the most useful treatise on the subject ever produced in any language. But his ability did not end with the mastery and elucidation of principles enunciated by his predecessors; his own

Jan 1, 1920

By L. E. Young

LOADING machines may be classified in several ways: (1) Machines which cut or break down and load .the coal; (2) machines which simply load the coal; (3) devices which load and transport the coal; (4) de-vices which elevate; (5) devices which transport the coal after it has been shoveled onto the device. There are many types of mechanical loading devices, Bull. 17, Coal Mining Investigations, under the auspices of Carnegie Institute&apos; of Technology, U. S. Bureau of Mines, and the Advisory Board, listing 31 exclusive. of -the large shovels used in thick coal seams. Mechanical loading of coal is not in its infancy; I think some of the early patents go back to 1890. One large coal company, properly called the early leader in this field of mechani-zation, has about 26 large machines at work. This company spent about thirty years in developing a ma-chine, and at the present time is loading approximately two million tons of coal a year in its mines. The chair-man directed a question at the previous speaker; inquir-ing if real progress was being made in mechanical load-ing. The experience of the company just referred to is in itself an adequate answer. A review of a list of mines using mechanical loading devices shows that there are 28 mines which we may say are 100 per cent mechanical. There are four more mines which have been 100 per cent mechanical, but which are idle at this time on account of labor condi-tions. There are at least 25 more at which the tonnage is more than 50 per cent mechanical. In speaking of a 100 per cent mine I do not mean that every pit car of coal is loaded by machine, because when complete, re-covery of the coal is attempted it is not practical to load all the coal at, the break line. In order to load the last 5 to 10 per cent of coal with a minimum of gob material and in order to keep the. working places along the break line timbered in a safe manner it is generally desirable to use a few hand loaders. At a certain mine operat-ing on the block system 90 percent of the coal is being loaded by what is properly a mechanical loading: device, and about 10 per cent -is being loaded by hand. This 10 percent is right off the break line, out of what might be called, the screen pillar. The mines referred to are scattered over the country, . in seven different&apos; States, and the equipment used is produced by ten different machinery companies. As to size, these mines vary from small mines of 500 tons mining capacity-up. In one instance a company with one loading machine is producing an, average of 450 tons per day. One of the large mines that is idle pro-duced at the. rate of 4300 tons per day, of which 97 per cent was actually loaded by machinery.

Jan 8, 1928

By Y. A. Chang

Phase relationships in the system Cr-Si have been established based on the melting point, X-ray, metallo-graphic, and DTA studies. The three intermediate phases, Cr3Si, Cr5Si,, and CrSi,, melt congruently at 177V ± I@,Cr3Si, 1680"i 20°, and 1490" *20°C, respectively, while the fourth intermediate phase CrSi, melts peritectically at 1413" i 5°C to Cr5Si3 and a melt containing 51 at. pct Si. The temperatures and compositions of the four eutectic isotherms occurring in this system are given below: DTA and metallographic evidences indicate that Cr5Si, undergoes a phase transformation at 1505" i20°C. The high-temperature form of this phase could not be retained by the quenching techniques used in this study. TECHNOLOGICAL interest in the developing of composite systems, consisting of Sic on the one hand as a fiber-reinforced material and metallic substances such as chromium, nickel, or Cr-Ni alloys as a binding agent on the other hand, stimulated the present investigation of phase relationships in the binary system Cr-Si. Earlier works concerning this system have been evaluated and summarized by ansen and Anderko.&apos; Their phase diagram was based mainly on the works of Kieffer, Benesovsky, and schroth2 and Kurnakov.~ According to these authors, the three intermediate phases Cr3Si, CrSi, and CrSi, all melt congruently at approximately 1730°, 1600°, and 1550°C. However, they did not agree on the compositional stability of the fourth intermediate phase between Cr3Si and CrSi. Later Parthe, Nowotny, and schmid4 determined the structure of this phase to be tetragonal T-1 type using the single-crystal method, and concluded that this phase had a formula of Cr5Si3. Since the compilation of Hansen and Anderko,&apos; a new phase diagram for the system Cr-Si has been proposed by Elliott5 based on the works of Goldschmidt and rand,&apos; Guseva and ~vechkin,~ and Trusova, Kuzev, and Ormont8 and the earlier works quoted by Hansen and Anderko.&apos; According to this proposed phase diagram, all four intermediate phases have large ranges of homogeneity and all melt congruently. More recently, Svechnikov, Kocherzhinskii, and yupkog studied the system Cr-Si by the DTA-method. According to their findings, the three intermediate phases, Cr3Si, Cr5Si3, and CrSi,, melt congruently at 1700°, 1720°, and 1475"C, respectively, while the fourth intermediate phase, CrSi, melts peritectically at 1475°C to Cr5Si3 and a melt containing 50 at. pct Si. The temperatures and compositions of the four eutectic isotherms were found to be: In view of the discrepancies existing in the literature concerning the system Cr-Si, it was decided to rein-vestigate the phase relationships in this system. EXPERIMENTAL a) Starting Materials. Chromium disilicide and chromium or silicon powders were used in the present study to prepare the melting point and DTA samples. CrSi, was obtained by directly reacting cold-pressed elemental powders in an atmosphere of Hz at a temperature of about 1250°C. Chromium powder, purchased from Stark Chemical Co., had the following impurities in ppm: Fe, 200; Mg, 1000; and 0, 250; while silicon powder, purchased from the Welded Carbide Co., had the following impurities in ppm: Ca, 700; and Fe, 3500. b) Melting-Point Determination and Differential Thermal Analysis. Cylindrical melting-point samples of approximately 13 mm in diam and 30 mm in length with a rectangular groove in the center were prepared by hot-pressing of well-mixed powder mixtures in graphite dies. Before the melting-point determination, the hot-pressed samples were ground on a sand paper to remove any minute surface contamination of graphite. A small hole of 1 mm in diam, drilled on the center portion of the samples, served as a blackbody cavity for the temperature measurements. DTA samples approximately 13 mm in diam and 15 mm in length were prepared in a manner similar to the melting-point samples. Melting points were determined using the Pirani technique under a helium atmosphere of 40 psi. The design, performance, and operation of this apparatus have been described in detail by Rudy and ~ro~ulski.&apos;~ The temperature measurements were carried out with a calibrated disappearing-filament-type micro-pyrometer. The measured temperature was corrected for losses from the quartz window of the melting-point furnace and for deviations from blackbody conditions of the observation hole. The procedure for temperature correction has also been previously described." The DTA method of Heetderks, Rudy and Eckertl&apos; was also used to check any phase transformations of selected alloys in the system Cr-Si. It was not possible to make remated runs on the same sample once melt-

Jan 1, 1969

By C. E. Silverblatt, D. A. Dahlstrom

Previous bench-scale studies demonstrated that a substantial moisture reduction can be obtained by the application of steam to coal filter-cakes, particularly to those containing a limited amount of minus 200-mesh material. Consequently, U.S. Steel&apos;s Applied Research Laboratory conducted a study to determine the feasibility of steam filtration of 1/4 in. by 0 coal on a continuous pilot-scale installation in which an Eimco extractor is used. The test results showed that the moisture content of this coal could be reduced to 5.5% at a steam loading of about 175 lb of steam per ton of dry cake. In terms of steam consumption, this loading is calculated to be 1-1/2 lb of steam per lb of water removed. In some tests, only 1 lb of steam per lb of water removed was required. These levels of steam consumption are significantly less than the actual heat requirements of conventional thermal dryers. The satisfactory moisture reductions were obtained at filtration rates of 125 to 186 lb of dry solids per sq ft per hour. However, the proper design of commercial filters should improve the potential rates that can be attained. These results indicate that steam filtration has considerable economic potential for drying 1/4 in. by 0 coals and also has additional advantages over the conventional thermal drying of coal. The results of the previous bench-scale studies and those published by Burton&apos; demonstrated that a substantial moisture-content reduction can be effected by the application of slightly superheated steam to coal filter-cakes, particularly to those containing a limited amount of minus 200-mesh material. Consequently, US Steel&apos;s Applied Research Laboratory conducted a study to determine the feasibility of steam filtration of 1/4 in. by 0 coal on a continuous basis. In the continuous process, the dewatering operation on the filter is conducted in stages. In the first, the bulk of the water in the feed slurry is removed by conventional mechanical dewatering on a portion of the filter before the steam is applied. In the second stage, steam is applied to the cake. The steam condenses and releases its latent heat, thereby reducing the viscosity of the remaining cake water; this reduced viscosity then facilitates further drainage and produces a cake of lower moisture content. Because of the availability of feed coal on a continuous basis and since steam was readily available from a low-pressure boiler, the Applied Research Laboratory selected for the test site a coal-preparation plant that cleans Pittsburgh Seam coal. A slurry of table and flotation coal in percentages as they occur normally was used as feed stock. Typical analyses of this slurry are shown in Table I. DESCRIPTION OF FILTER AND EXPERIMENTAL PROCEDURES An Eimco Extractor was selected for the evaluation of steam filtration in a continuous process. This unit was chosen because of its availability and its design features that permit relatively simple hood construction, instrumentation, and operation. A photograph of the Extractor is shown in Fig. 1. In the filter a cloth medium is used that travels horizontally and continuously with a grooved, rubber drainage belt. The total effective filter area was 12.5 sq ft. As the feed slurry flows by gravity from the feed box onto the medium,

Jan 1, 1964

By Oberlin Smith

The experiments described in this paper are very incomplete and only preliminary to those I hope to make in the future. Having had a good deal of experience in cutting, forming and drawing sheet-metals, and feeling a great interest in the commercially new and wonderful metal, aluminum, I applied to my friend, Mr. A. E. Hunt, for some specimens in sheet-form, that I might, from time to time, test its working-properties in presses with which we happened to be experimenting at the works of the Ferracute Machine Company. The chances for such trials being accidental only, and the time having been limited to the last few weeks, no crucial experiments have been tried, and no exact data have been obtained for a rigid comparison with other metals. The results of what little we have done, however, are shown in the articles exhibited in connection with the reading of this paper, which comprise various cups, plates, boxes, bells and cartridge-cup and shells. For the latter I am indebted to my friend, Mr. Hobbs, of the Union Metallic Cartridge Co., who, at my request, ran several pieces of sheet-aluminum through the dies with which he was making brass cartridges. The specimens are rougher than they would be had the metal not been a little too thin for the particular dies which he happened to be running.

Jan 1, 1890

By Harold Rabling

The following notes are taken from results obtained on a standard 25-ft. Hancock jig1 tested during regular operation in the Bonne Terre mill of the St. Joseph Lead Co. The object of the tests was to determine the conditions for most effective work, and the nature of products that could be made. The material treated was sized between 9-mm. and 2-mm. round-hole screens, and was constant throughout the experiments. Three products were made, concentrates from the first three hutches, middlings from the fourth and fifth, and tailing from the sixth. The middlings were crushed in one pair of Allis-Chalmers Style B, 30 by 14-in. rolls, and elevated with the original ore to the 2-mm. screens, oversize of which formed the jig feed. While this arrangement was very simple, it gave rise to undesirable crowding of the circuit. Table 1 shows tonnage and assay values of the jig feed and products at the beginning of the experiments, and brings out the excessively large amount of middlings, comprising 63.3 per cent. of the total material fed to the jig. The rolls, being heavily overloaded, did very little crushing, a screen analysis of the product showing that only 27 per cent., or 128 tons, was crushed fine enough to pass to the tables. The remaining 347 tons returned to the jig with 400 tons of original ore. At .times, this overcrowding became much worse, and the tonnage in circuit grew to enormous proportions. It became imperative

Jan 1, 1918

By John D. Ridge, Robert C. Barwick

The amount of lead in concentrates that moved in international trade in 1952 was only 16 pct of the world mine production of lead and was less than 27 pct of the total of lead in concentrates and lead metal that traveled from one country to another. Because almost all lead is derived from galena, lead concentrates are high grade, with a theoretical maximum of 86 pct lead, and can be shipped as such without transporting a considerable weight of waste material. It would not be surprising, therefore, to find the large share of lead in international trade moves in concentrates (Rule 5). This is not, as has just been mentioned, actually the case. There is more than one explanation for the situation. Lead smelting is not a particularly difficult process and is one for which smelting equipment can readily be made of the best size for the tonnage to be handled. Another factor that encourages local smelting is the effort of many mining countries to see that a maximum of profit from their raw materials remains in the home country. Still another factor is the newness of large scale lead mining in two of the three largest exporters of lead in concentrates. In these countries, South West Africa and French Morocco, there has not yet been time to erect enough smelting capacity to process all of the concentrate output. Even in these countries, however, it will not be long, if present trends continue and plans are fulfilled, before most or all of the lead mined is domestically smelted.

Sep 1, 1955

By J. Washburn, R. Drouard, E. R. Parker

Temperature dependence of the rate of recovery in zinc single crystals after a simple shear deformation at low temperature was investigated. Some tentative suggestions regarding the annealed and strain-hardened states of a crystal are discussed. RECOVERY may be defined as the gradual return of the mechanical and physical properties of strain-hardened metal to those characteristic of the annealed material; an increase in temperature increases the rate of recovery. The annealing process in strain-hardened polycrystalline metals is complicated by the inhomogeneity of strain which always exists in aggregates. Polygonization in bent regions of the crystals and growth of new almost strain-free grains starting at points of severe local distortion1-:&apos; make it almost impossible to isolate and study the recovery process. Homogeneously strained single crystals, however, do not polygonize or re-crystallize and hence they can be used advantageously to study recovery. In such crystals strain hardening is completely removed by recovery alone. Since recovery is a process whereby certain lattice disturbances introduced by plastic flow are gradually reduced, a knowledge of the rate and temperature dependence of this process for various conditions of prestrain might be helpful in formulating a model of the strain-hardened state. For simplicity it seemed desirable to limit the type of prestrain to the simplest obtainable, i.e., simple shear strain. In the experiments to be described, recovery was studied by observing changes in the stress-strain curve of prestrained zinc single crystals held for various times at temperatures above that employed for straining. Single crystals were grown from the melt by a modified Bridgeman technique from Horse Head Special zinc 99.99 pct pure, and from spectrographically pure zinc 99.999 pct pure. They were grown as 1 in. diameter spheres and acid-machined&apos; to the final specimen contour. The test section was a cylinder about 1/8 in. high and 3/4 in. in diameter. The conical sections adjacent to the test section were cemented into the grips so the load could be transmitted to the crystal as uniformly as possible. The specimens were oriented so that in testing the maximum shear stress was applied along one of the slip directions, [2110], in the (0001) plane. Details of the production and testing of such specimens have been presented.&apos; Each test was carried out according to the following schedule: 1—The crystal was strained at — 50°C until it reached a maximum shear stress, ,,,. The strain rate was approximately 5 pct per min in all cases. 2—After straining, the crystal was unloaded before the temperature was changed. Unloading required about 3 min. 3—The temperature of the specimen was then increased from — 50°C to the temperature, T, of recovery. This change in temperature was completed in a time of less than 2 min. The specimen remained at temperature, T, for a time, t, which differed for the various specimens. 4—Thereafter the temperature was again reduced to — 50 °C in approximately 3 min. 5—While at —50°C, the stress-strain curve after recovery was obtained. 6—The specimen was then unloaded and annealed for 1 hr at 375 °C in a helium atmosphere to bring about complete recovery. Cooling to room temperature after anneal required 90 min. 7—The same crystal could be re-used for another test because the plastic properties after annealing closely duplicated those of the original crystal. The specimen was immersed during the test in a bath of methyl alcohol which, through a system of tubes, could be pumped through either of two heat exchangers to regulate the temperature; this was accomplished by circulating the liquid through coils immersed in a bath of acetone and dry ice for cooling or in a bath of warm water for heating. Test temperatures were thus maintained constant within ±1°C. The — 50°C temperature was low enough so that no measurable recovery occurred during unloading and reloading. The stress-strain curve continued after recovery along a path below, but approximately parallel to, the path of a curve obtained in an uninterrupted test. Fig. 1 shows some of the results from a specimen of 99.999 pct Zn. The amount of downward displacement of the curve due to recovery was a

Jan 1, 1954

By L. W. Rowe, W. R. Opie

A brief history of TiCI, production and purification is given. Chlorinator feed materials for the production of TiCI4 are classified. The thermodynamics and kinetics of Ticl4 production by chlorination of TiO2 are discussed. Problems encountered in the chlorination and purification steps are outlined in detail. MOST of the current processes for the production of titanium metal require the use of TiC14 as a source of titanium values. This material can only be produced by a dry chlorination process, since it is immediately hydrolyzed in the presence of water. When pure, the tetrachloride is a colorless liquid boiling at 136°C. It fumes readily in moist air, reacting immediately with the moisture to form TiO, and HC1. History The tetrachloride was prepared as early as 1826 by DumasL who chlorinated a red hot mixture of carbon and TiO,. Since then, numerous other mixtures have been used including rutile, ilmenite, beneficiated ilmenites, titanium pigment, slags, and the various titanium metalloids such as TiN, TiCN, TiOC, and TiS2. S2Cl2, phosgene, and CC14 have been substituted for chlorine and CO has been used in place of carbon.

Jan 1, 1956