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By C. H. Fulton

Page Introduction........................... 280 Distillation Products from Reduction of Zinc Ore........... 281 Preliminary Investigations..................... 290 Equilibrium of Reaction Zn + CO2 + ZnO + CO in Temperature Range of Condensation........................ 293 Requisites for Successful Condensation................ 299 Discussion............................ 300 Introduction The study of the condensation of zinc from its vapor was undertaken to shed light on certain problems encountered in large-scale electric zine-furnace work. recently conducted. It is a matter of common knowledge that one of the disadvantages of the arc type, electric zinc furnace, is the production of a large amount of blue powder and proportionately little liquid spelter, for, as stated by Stansfield,l "A notable defect in the electric smelting of zinc ores is the difficulty experienced in obtaining the distilled zinc in the liquid state; ...... when zinc ores are smelted electrically, very little liquid metal is commonly obtained, nearly all of the zinc being in the state of powder." This difficulty was not encountered in the electric furnace used12 the main difficulty being the destruction of the fire-brick lining of the large condenser, in certain parts, and the formation of .some oxide and dross coatings on the condensing surfaces. The reason for these difficulties could readily be explained by the infiltration of air whenever the condenser was changed from one retort base to the other, the zinc absorbed in the fire-brick forming oxide and causing rupture by its expending volume. Two facts, however, tended to disprove this theory for the rupture of the fire-brick lining: first, the large distilling retort, lined with fire-brick, which was shifted from charge to charge on alternate bases at temperatures between 1200 and 1300 C., fully exposed to the air, showed no signs of disintegration whatever; second, marked disintegration in the condenser occurred .only in places that were at tempera-

Jan 1, 1919

By P Shenon

THE Elk City district is in north-central Idaho about 60 miles east of Grangeville and near the headwaters of the South Fork of the Clearwater River (Fig. 1). At the height of its boom in the early sixties, Elk City had a population of more than 2000 people.1 Published estimates of the placer production from the district range from $10,000,000 to $18,500,000. Although the first quartz-vein location was made as early as 1870, very little gold was extracted from quartz ores until after the completion of the American Eagle mill in 1902. Between 1902 and 1932 a total of from $750,000 to $1,000,000 was taken from about six properties.

Jan 1, 1934

By C. E. Birchenall, J. R. Stubbles

ThE equilibrium between lead, lead sulfide (PbS), and atmospheres of H2 and H2S has been determined previously by Jellinek and Deubel,' and SudO.' Blbem and Kroger3,4 used Jellinek's data to calculate the sulfur dissociation pressures of PbS crystals (of

Jan 1, 1960

By John Mark Patek

Knowledge of the relative floatability of silicate minerals is increasing in importance as flotation is being applied to the concentration of nonsulfides. Many silicates are in themselves commercial products amenable to concentration by flotation. Moreover, the selective flotation of other nonsulfide minerals, such as cassiterite, depends largely upon the floatability of associated gangue silicates. Differences in floatability existing between the various silicates have not- been sufficiently appreciated; for example, the feldspars that differ greatly in floatability have generally been merely treated as "feldspar." It was the purpose of the work described in this paper to determine by experiment the differences in floatability between silicates; to investigate the causes for such differences, and to discover a means of predetermining approximate floatability without the necessity of experimentation. Determining Floatability The relative floatability of 20 silicates so selected as to represent all of the more common silicate types1 was obtained by flotation tests enumerated in Table 1. The mineral to be floated was crushed dry on a steel plate, and screened repeatedly during crushing through an 80-mesh screen in order to produce a sand with all grains as close to 80 mesh as possible. The sand was placed in dilute (6N) hydrochloric acid until free of soluble foreign material, and then washed with tap water about ten times in order to remove both acid and fines. The resultant product, which averaged 82 per cent plus 200 mesh, was floated in 50-gram charges in a 50-gram Denver celluloid flotation machine with 0.008 gram of terpineol, and from 0.01 to 0.05 gram of oleic acid in a solution acidified with sulfuric acid. The degree of separation of one mineral from another was determined by counting under a nlicroscope the grains of each mineral, both in the concentrate and in the tailings, and comparing their relative abundance in each. Unless the comparison showed a decided difference in amount,

Jan 1, 1935

By P. Lees, N. Parkinson, K. Hartley, D. M. Donaldson

The reprocessing of advanced fuels such as carbides, oxides, and cermets, containing up to 30pct pu has been studied. Dissolution of uranium carbides in nitric acid produces appreciable quantities of mellitic acid which has undesirable effects in subsequent stages of the process. Mixed oxides containing up to about 40 pct Pu in solid solution with UO, are soluble in nitric acid and a leaching type process in nitric acid for a stainless steel/UO,. PuO, fuel containing 30 pct Pu appears to be feasible. It offers considerable economic advantages THE reprocessing of the U-Cr alloy core of the Dounreay Fast Reactor was described by Buck and others at the Second Geneva conference.' This paper described the flowsheet and plant for processing a relatively simple fuel of good dissolution charac- over total dissolution routes. A new oxidation-sub -limation process is described for metallic fuels containing up to 12 pct Mo. New data is presented on the solvent extraction of uranium and plutonium nitrates into tributyl phosphate -odorless kerosene and of the influence of radiolytically produced acid phosphates on this part of the process. It is concluded that there are no insuperable difficulties which will prevent the satisfactory reprocessing of high burn-up plutonium fuels by a solvent extraction route. teristics and of low-plutonium content after irradiation. However, it has been clear for some time that more satisfactory operation of the reactor can be obtained by the use of a core with better irradiation performance than U-Cr alloy and a U-Mo alloy will be used for the next charge. Recent modifications to the core mean that it is now possible to carry out irradiations of fuel element subassemblies similar to those which might be used in a fast power reactor and trials with plutonium-bearing fuel elements will be made in the relatively near future. These changes have meant that a considerable amount of reprocessing development work has had to be carried out for

Jan 1, 1963

By L. D. Jaffe, J. H. Hollomon

THE effect of tempering temperature and time upon the properties of quenched steel is clearly a subject of great practical importance, as well as of considerable theoretical interest. It would be very desirable to be able to predict the properties of a quenched steel when given any selected tempering cycle, with a minimum of experimental work upon that heat or even type of steel. Two problems are involved: one consists of relating the structure obtained to the physical properties, and will not be discussed here; the other, with which this paper deals, involves the relations of time, temperature and composition with the structure obtained on tempering. Indentation hardness is perhaps the most convenient quantitative measure of the tempered structure, or of what might be called the "degree of tempering." Undoubtedly, it is not an exact measure, and in some cases (as when temper-brittleness occurs) pieces of the same quenched and tempered steel may have widely differing properties at the same hardness. However, hardness has the advantage of being simple to determine and is certainly the most widely used indication of the degree of tempering. Moreover, for fully quenched steels that are not temper-brittle and do not contain retained austenite when quenched, it appears that, in general, if the hardness of the steel is the same, the tensile and impact properties will also be identical, whether a high or a low tempering temperature is used. The tempering charts available in the metallurgical literature usually give the hardness as a function of tempering temperature for only one tempering time. However, in practice, tempering times frequently vary, and a method of converting tempering curves for one time to tempering curves for some other time would be very valuable. It is also advantageous, in determining the tempering treatment necessary for a given part, not to have to temper samples at several temperatures for the time used for the commercial tempering operation. A more satisfactory procedure would be to employ times of the order of 10 to 30 min., rather than 5 or 10 hr., and if possible to use only one temperature. Furthermore, it is frequently desirable, for reasons such as temper-brittleness,* to obtain a given hardness with short times at relatively high temperatures, and it would be convenient to be able to compute without tests the time required to produce this hardness. Remarkably few quantitative studies of the hardness of quenched steel tempered over wide ranges of temperature and time

Jan 1, 1945

By S. H. Gelles

Samples of poly crystalline zinc of 99.999+ pct purity were observed metallographically after having been exposed to hydrostatic pressures of up to 27 kbars. The deforrnation produced by this treatment was analyzed using X-ray and metallogaphic techniques. Basal-plane slip occurred universally in all grains exumined at the lowest pressure used (8 kbars). At pressures of >23 kbars, {1012} twin nucleation and growth were noted as well as slip. Formation of bend planes, complex kink bands, and recrystallization at the gain boundaries were also observed in this pressure range. These observations are discussed in reference to the expected deformation behavior of zinc under high hydrostatic pressure. It has been shown over the past few years1'3 that anisotropic, poly crystalline metals can be made to deform plastically by the application of a hydrostatic pressure. The effect is greater 1) the larger the anisotropy of linear compressibility and 2) the smaller the stress level needed to produce plastic deformation. Zinc having both very anisotropic linear compressibilities and a very low critical resolved shear stress (CRSS) for basal-plane slip has been shown to exhibit large amounts of plastic deformation when subjected to a hydrostatic pressure.2,3 At pressures up to 15 kbars, grain boundary migration and slip on one set of glide planes have been reported.' After exposing samples to 20 kbars pressure, grain boundary migration, single slip, multiple slip, and twinning have been noted.' The identification of the deformation modes operative under these conditions has not been reported. It was the purpose of this research to identify the deformation modes induced in poly crystal line zinc by the action of a hydrostatic stress and to study the strain accommodation at grain boundaries. Hydrostatic pressure could affect the operational modes of deformation by altering the Peierls-Nabarro stress. This may be roughly approximated by the relationship4

Jan 1, 1967

By M. Muskat, H. H. Evinger

ALTHOUGH the shooting of oil wells for the purpose of increasing production has been practiced since 1866, present-day shooting technique has been arrived at almost wholly by a process of trial and error. The difficulties attending either a theoretical analysis of the problem or an experimental attack become apparent when one actually embarks on a theoretical investigation or attempts to formulate an intelligent experimental program. The literature on the subject consists mainly of descriptions of current practice, scattered eye-witness accounts of events following the shooting of a well, and vague speculations on the mechanical processes involved. In contrast to quarry blasting, the results of oil-well shooting cannot be determined by means of visual inspection, and it is perhaps for this reason that only one attempt at what approaches a direct experimental attack has been reported in the literature.1 In these experiments, charges of liquid nitroglycerin were exploded in holes drilled in a sandstone outcrop. In order to observe the character and extent of the resulting fractures, the rock was blasted away so as to expose the original shot holes. After all this had been done it was found impossible to distinguish the fracturing due to the original shots from that due to the subsequent blasting. The enlargement of the holes due to the pulverizing action of the shots was. measured and an attempt was made to determine the effectiveness of 'sand tamping. Only five shots were made and few definite conclusions could be drawn. Some small-scale experiments to determine the effect of tamping were performed by Snelling and Hall,2 Small charges (20 grams) of dynamite were detonated at the bottom of a cylindrical hole in a lead block and the resulting enlargement of the hole was taken as a measure of the effectiveness of the explosion. It was found that when the shot was tamped with a sufficient amount of sand or clay, the volume enlargement was approximately double that found when no stemming had been used. The properties of the explosives have been the subject of much study by the manufacturers, the U. S. Bureau of Mines, and various other agencies. For example, velocities of detonation for many commercial explosives are to be found in the Blasters' Handbook, issued by the Du Pont company. Many other properties are given in a treatise on the subject by Naoum.3 The shock wave that accompanies the detonation of high explosives has been studied photographically by Payman4 and others. The hydrodynamical theory of the shock wave has received much attention, and an extended theoretical treatment is given by Bateman.5 Two aspects of the well-shooting problem will be considered in this paper; namely, the fracturing of subsurface strata, and possible damage to casing. With respect to the former of these, several calculations have been made giving the stresses in the rocks surrounding the shot. In order to arrive at numerical results at all, however, it is necessary to introduce a great many simplifying

Jan 1, 1941

By C. P. Watson, R. E. Collom

Various chapters already written in the history of development of the North Dome of Kettleman Hills are monotonoysly identical in the one underlying' theme of conservation of oil and gas. Discovered on Oct. 4, 1928, by Milham Exploration Co. with its wildcat Elliot No. 1, the field has been subjected to practically every modern form of production restraint in the name of conservation. The record thus far developed shows that conservation was had for a time, at a price; and that unitiza-tion must be blessed by single ownership or 100 per cent participation to be effective. In fact, incomplete unitization places a heavy handicap upon its participants in the competitive development that follows. Shut-in Agreement of July 25, 1929 Not long after discovery at Kettleman but after the Continental Oil Co. and the Standard Oil Co. had completed several producing wells in the discovery group, came the so-called Shut-in Agreement negotiated at the instance of the Department of the Interior. This agreement became effective July 25, 1929. The fundamental purpose of the agreement was to prevent bringing on production of some 30 wells then being drilled and forestall a flood of Kettleman oil on the market. A cooperative scheme was developed whereby wells in the discovery group would continue to produce. Two of them could not be shut in. Drilling wells would be completed to a water shutoff in top of Temblor and operations suspended. Producing wells would contribute the value of 10 to 25 per cent of their production to the owners of suspended qualifying wells. The percentage rate of drainage contribution was left to a committee or umpire. Some acreage was not placed under the agreement. This same acreage later did not come into the Kettleman Unit Agreement. Several wells on this acreage did not contribute to the drainage fund. The total amount of oil produced during the 17 months of the shut-in agreement, by Milham, Continental and Standard from wells in the discovery group, was 5,297,262.22 bbl. The total amount paid out in "drainage" contributions was $2,046,048.18, representing sales value of 1,266,044.06 bbl. of oil.

Jan 1, 1937

By J. Redstone, A. R. Laplante

Sidbec-Normines operates six large iron ore concentrate regrinding mills in parallel and open circuit at its Port-Cartier pelletizing plant. Grinding kinetics in these mills were characterized for slurry densities varying between 70 and 89% solids, using a lumped parameter size discrete model. Optimum grinding conditions were encountered at 83.5 to 84% solids. Higher densities decreased the normalized selection function and increased slurry short-circuiting, yielding a sharply coarser mill discharge. At lower slurry densities, the normalized selection function decreased and the mill discharge coarsened slightly. The grinding kinetic model predicted particle size distributions within the mill. These were found to vary significantly from the feed to the discharge end. This is likely to cause nonlinear breakage kinetics.

Jan 1, 1985

By R. H. Thorpe

Longwall working in Britain developed to overcome problems arising from depth of seams causing roof and ventilation difficulties. This system became very widespread particularly in the thicker seams, where faces of up to one mile in length were not uncommon. In the thinner sections, in order to remain competitive, the longwall undercutting machine was developed. Following the development of the coal cutter, every other aspect of the face operation was examined and mechanized as it became a bottleneck to output and efficiency. The face system itself was modified and workings concentrated with the same objectives.

Jan 1, 1977

By M. F. Goudge

Production of many industrial minerals reached all-time records in 1965. In keeping with the high level of industrial activity throughout the nation, producers of many industrial minerals operated at capacity or near capacity, notably the producers of phosphate, potash and sulfur. In the case of sulfur, the demand exceeded production and orders were filled, in part, from stocks accumulated in previous years. Industrial minerals as a group continued to increase both in value and quantity at a faster percentage rate than metallic minerals and fuels, The U.S. Bureau of Mines estimated that the value of industrial minerals produced in 1963 was $4318 million vs. $2006 million for metals. Preliminary estimates for 1965 indicate that current value of production was again more than 2% times that of metals, thus making apparent their importance to the industrial life of the nation.

Jan 2, 1966

By R. E. Goodman, M. A. Mahtab

The, state of stress around a vertical wellbore in rock following nonlinear stress-strain laws is examined by means of finite element analysis. The wellbore, is considered an axisymmetrier body with axisymmetric loading. The initial vertcal and borizontal stresses are "locked" in the rock elements around the wellbore and a new state of stress is generated by the displacements which occur around the borehole. A point-uise variation of the elastic moduli is made on the basis of the new stress state and the triaxial data. The initial stresses tire now reintroduced along with tile changed moduli and original boundary constraints. This procedure is repeatrd until convergent stresses are reached. The effect of nonlinearity on streases is examined for a 6,000-ft wellbore in a scbistose gnezss and Berea sandstone using results of laborratory triaxial compression tests. The results sbou that the effect is restrited to one well radius from the bottom periphery of the bole. Beyond a distance of one-quarter radius, the elfect of nonlinearity on stresscs IS almost always less than percent for the cases conszdered, The consideration of a static pressure inside the well does not magnify the effect of monlinearity on borehole stresscs. INTRODUCTION The terms " wellbore" and "borehole" here designate cylindrical openings in the ground with vertical axis and a circular cross-section. A knowledge of the stress redistribution that occurs on excavating a wellbore is important in understanding (1) the behavior of the lined or unlined hole, (2) hydraulic fracture response, and (3) the effect of stress redistribution on drillability; also it is important in predicting initial stresses in the virgin ground, and in analyzing the response of measuring instruments placed in the borehole. Our knowledge of the state of stress around a wellbore has been restricted to homogeneous, isotropic, elastic material and derives chiefly from the analysis by Miles and Toppingl and the photoelastic work of Galle and Wilhoit2 and Word and Wilhoit.3 In this investigation the state of stress is examined for a nonlinear elastic material by means of finite element analysis. Many rocks possess stress-strain curves that depart notably from straight lines in their initial or final portions. While the literature contains abundant stress-strain data from triaxial tests (axisymmetric loading) on cylindrical rock specimens, there is little information on rock deformability under nonaxisymmetric loading conditions such as occur at each point around the bottom of a wellbore. Although there is some knowledge of the effect of intermediate principal stress on rock strength, there is virtually nothing known about its effect on rock deformability; therefore, we have assumed here that the effect of intermediate principal stress can be ignored. A schistose gneiss4 and Berea sandstone5 were selected as representative rocks for this analysis. The traditional graphs of deviator stress (ol -o3) vs axial strain were reworked to give the tangent modulus as a function of the deviator stress for varying values of the minor principal stress. The result is a nesting family of skewed, bell-shaped curves for tile gneiss (Fig. 1A) and the sandstone (Fig. 2A). A similar replotting of the lateral strain data defines the variation of Poisson's ratio (v) with the deviator stress and confining pressure. These curves, shown in Fig. 1B for the gneiss and in Fig. 2B for the sandstone, are not so well ordered as the tangent modulus curves. However, all of these display an increase of v with deviator stress application, but the rate of increase diminishes with confinement. The ET and v curves for the two rock types are tabulated in Tables 1A and 1A for use in a digital computer so that material properties corresponding to a given state of stress can be assigned by interpolation. STATEMENT OF THE PROBLEM Given a state of stress in the ground prior to drilling a hole (initial stresses), we assume that

Jan 1, 1969

By William Phillips

This paper was prepared at the request of Capt. A. F. Lucas, Chairman of the Institute's Committee on Petroleum and Gas, as a preliminary discussion of the fuel oils which are used-in the Southwest, giving their composition, uses, prices, etc. Should it afterward be found desirable, these observations may be extended over a larger area. In this connection, J suggest that samples of all kinds of fuel oils, including various tars, from all over the country, be collected and sent to some testing laboratory for examination. We would be glad to extend the facilities of the laboratory of the Bureau of Economic Geology and Technology, at the University of Texas, for this purpose, and to do the work free of all expenses. After such examinations are made and the results classified and studied, it would be possible to suggest specifications under which fuel oils should be purchased, and to arrive at some conclusions respecting the uniformity of such specifications, with due allowance for climatic and other more or less local conditions. While such specifications do not now depart from a common standard anything like as much as specifications for illuminating oils do, yet there are discrepancies which should not exist. Some of these discrepancies are of lessening importance, due to the pronounced tendency to distill every crude oil that can be distilled with profit, and to send residues into the market for fuel oil. Residues from the refineries are of a more uniform chemical composition and physical nature than many of the crude oils that go direct into the fuel market. The lower flash-point oils are disappearing from the fuel trade and in place of them we are getting oils that do not flash below 220° F., nor burn under 320° F. In the Southwest, it has not been long since we had fuel oils that flashed at as low as 110° F., and the average flash point over a considerable period was 151° F. Now we are using oil that flashes at about 30° lower than the former burning point, which was 256° F. In other words, the flash point has risen, on the average, 100°; and the burning point about 75°.

Jan 6, 1914

By Larry D. Hartzog

PANELISTS Paul Chamberlin, Nerco Minerals Jim Gourdie, Goldfield Mining Corp. Roger Leonard, Cyprus Northumberland Mining Co. Eric Daniels, Tenneco Minerals John Dasher, Consulting Metallurgist Bob Shoemaker, San Francisco Mining Associates Larry Hartzog, Bechtel Civil and Minerals, Inc.

Jan 1, 1984

By G. W. Mao, A. M. Gaudin, D. W. Fuerstenau

Activation of sphalerite with copper salts has long been thought of as a chemical reaction of the following form: ZnS + Cu++ [=] CuS + Zn++ [ 1 ] Early experimentation1-3 showed that the reaction seemed to be stopped by the coating of insoluble copper sulfide, but since the analytical methods were crude, it was only surmised that the reaction could proceed by diffusion. Probably the most conclusive evidence for reaction (Eq. 1) was obtained by Cooke,4 who found a stoichiometric replacement of Zn++ by Cu" after 50 days' reaction at about 100°C. Cooke also found the sphalerite to be covered with a rather thick coating of covellite, which in¬dicates that activation is a continuing replacement of Zn++ by Cu" rather than diffusion of Cu" throughout the sphalerite lattice. However, the occurrence of diffusion at high temperatures has been observed.5,6

Jan 4, 1959

By S. Zador, C. B. Alcock, K. Sudo

Measurements have been made of the standard free enevgies of formation of the sulfates of cobalt, Cupric copper, nickel, and ferric iron in the temperature range of 750° to 950°C. Dynamic gas-solid techniques have been employed in which oxide-sulfate and basic sulfate mixtures were placed in a stream of gas of controlled SO3 potentials. Thermal analysis and thermogvavimetry were used as detection methods, and it was found THE formation of sulfates during the roasting of sulfide ores is now considered to arise in many cases from the interaction of sulfur trioxide in the gas and the metal oxide which is formed on the sulfide as a first step.' As a preliminary to the investigation of the kinetics of sulfate formation during roasting, measurements have been made of equilibria from which the free energies of formation of cobalt, copper, nickel, and iron sulfates can be that the range of temperatures which could be investigated and the choice of method was largely controlled by the kinetics of these gas-solid reactions. The results are compared with previous results obtained from static measurements with which they agree quite well, and calculations have been made employing themal data to interrelate the present results with those for other sulfates. calculated. The method used has been to expose the solid sulfate (or basic sulfate) to a controlled flowing gas mixture of SO,, 02, and SOs and to observe the temperature of decomposition. The onset of decomposition was detected by thermal analysis or thermogravimetry. EXPERIMENTAL METHODS The thermal-analysis method was similar to that employed by Dewing and Richardson.' The sulfate was dehydrated at 250°C in air, and placed in a small alumina crucible which was held by a quartz ring in the hot zone of a horizontal furnace. The reaction tube of this furnace was made of mullite.

Jan 1, 1965

By James T. Kemp

Some interesting and, to American eyes, rather unusual processes for refining impure aluminum derived from scraps were found by American and British investigators who went into Germany in 1945 for the Technical Industrial Intelligence Committee of the Joint Chiefs of Staff. What was found was recorded in a series of reports (see page ), many of which have been released for general reading. This paper gathers under one title and summarizes the German work in refining light metal scrap. Reference must be made to the original reports for greater detail. Basically, the occasion and stimulus for the German developments in treating light metal scrap were hard necessity. Germany needed the metal for a rapacious war industry. Adequate supplies of new aluminum from reduction works were not assured. Great quantities of airplane and other light metal war scraps were forecast. It was evident that the scrap metal would have to be reabsorbed by the producing industry and would have to be kept of good quality. The normal current production of manufacturing scrap was being and could be consumed as generated. It offered no technical problem. The mixed scraps, especially those arising from crashed and decommissioned airplanes, however, presented problems of another kind. Airplane Scrap The recovery of usable aluminum alloy from the mixed assemblies that made up the piles of airplane scrap was attacked in different ways by different groups and with differing degrees of success. Three procedures actually were used on a commercial scale, one was in pilot-plant stage and another had come to a halt in the laboratory a year before Germany collapsed. Four of these five processes actually involved "refining"; that is, some measure of purification of the metal after melting. Sorting and Separation on a Sloping Hearth The simplest procedure for utilizing airplane scrap involved no refining in the strict sense of the word. This was the practice adopted by two representative plants visited by the author, the Leipziger Leichtmetalle Werke, Rackwitz, Saxony, and the Vereinigte Leichtmetalle Werke, Hanover. These firms did essentially the same thing that was done in England but not with equal success, to judge by their shorter experience, the smaller tonnage handled and by the number and quality of alloys produced. The two German firms named rough-sorted scraps by their easily recognizable alloys, essentially by part and shape. They used hand labor to chop and hack and tear apart. The easily separated heavy metal and nonmetallic scraps were discarded as they were found. Steel and the higher-melting-point metal parts riveted to aluminum or built into

Jan 1, 1947

By Charles Barrett

METALLURGISTS are making use of the stereographic projection to a steadily increasing extent. In the last five years no less than 20 papers in American metallurgical journals alone have employed the stereographic projection; recent books on physical metallurgy, plastic deformation, X-rays and their applications, and crystal structure use it. Mineralogists have used the stereographic projection for many years in the description of symmetry classes and crystal planes, for it presents an accurate, easily understood plot of any angular relations in crystals with all unessential features eliminated (such as the accidentally deter-mined size and shape of crystal faces). In metallography and physical metallurgy the projection is much used for the analysis of markings appearing on polished grains: slip lines, twins, cracks, structures formed by precipitation, magnetic-powder patterns, etch pits, etc. Data from certain types of X-ray photograms are most conveniently analyzed by its use, particularly those for determining the orientation of single crystals or the preferred orientation of grains in an aggregate. Calculations of how to tilt or cut a crystal parallel to a certain crystallographic plane or to reflect X-rays from a certain plane are rapidly carried out. It has been adopted almost universally to the exclusion of other methods by those studying the deformation of metallic crystals, save where the accu-racy required is greater than a few tenths of a degree. Any directional property in a crystal or polycrystalline material can be shown on a stereo-graphic projection; for example, the modulus of elasticity, yield point, etc. It has been repeatedly called to our attention that there is need of all elementary explanation of the principles and methods of stereographic projection, covering all the, common applications in the field of metal-lography and physical metallurgy. The following contribution is an attempt to fill this need. The description of each method is supplemented with references to publications in which the method has been used. For convenience to the reader, these illustrative references are chiefly in American journals, particularly the publications of the American Institute of Mining and

Jan 1, 1937

By R. A., D. L. Sponseller, Flinn

Using specially del'eloped titanium nitride crucibles and a pressurized syslem, it has been possible to determine the solzibilitv of liquid calcium in liquid iron and iron-base alloys. At 2925°F the solubility is 0.032 wt pet Ca in pure iron. The solubility is increased by aluminum, carbon, nickel, and silicon additions, and lowered by additions of gold. An inflection in the calcium-solubility curve occurs as carbon is added to iron. At approximately 0.87 Wt pet Ca the CaC, phase replaces liquid calcium, and the calcium concentration de- creases as more carbon is added to the iron. The maximum solubility, 0.36 wt pet Ca, was obtained in iron containing 10.5 wt pet Si. The data have important implications regarding the use of calcium in process metallurgy, as well as providing an interesting test of theories of metallic solutions. Reasonably good agreement is found with theories of Alcock and Richardson and of Wagner, and criteria are suggested which permit these theories to be applied more readily to systems of this type. AT the present time relatively little is known about the factors influencing solubility in liquid metals. Information of this type is important for such matters as the control of impurity levels in liquid metals, the use of magnesium in ductile-iron production, and the use of liquid-metal alloys as fuels and coolants in nuclear power plants. One important example of restricted solubility concerns the extent to which liquid calcium will dissolve in liquid iron. This is a matter of considerable interest in view of the strong potential of calcium for removing certain impurities in steel,. as well as the ability of calcium to desulfurize, inoculate, and produce spheroidal graphite in cast irons.' Since ferrous materials normally contain other elements in addition to iron, the interactions of third elements with the Fe-Ca system are of interest. In view of the foregoing, this investigation was conducted to determine the solubility of liquid calcium in liquid iron and the effects of various third elements upon the solubility. For reasons of theoretical and engineering importance, the elements investigated were aluminum, carbon, gold, nickel, and silicon. Numerous attempts were made in the early part of the present century to determine the solubility of calcium in both liquid iron and steel, employing a variety of open-melt and closed bomb-type systems.2-4 From the results of these tests Wever concluded that calcium is insoluble in liquid and solid iron.5 These investigations were unsatisfactory in that they failed to insure the presence of a liquid layer

Jan 1, 1964