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By M. Semchyshen, G. A. Timmons

The predominant orientation in both straight-rolled and cross-rolled molybdenum is the {100} [110] texture. Upon complete recrystallization, this same texture predominates, but there is less spread about the ideal orientation. A secondary orientation about the [111] direction as the axis develops in cross-rolled sheet. Compression-rolled sheet exhibits random orientation in the plane of the sheet. Some mechanical properties were measured at varying angles to the rolling direction to determine the effect of preferred orientation on anisotropy in molybdenum sheet which had been straight, cross, or compression rolled. THE development of the arc-cast process has made available large ingots of molybdenum from which it is possible to roll sheet of considerable size. It is anticipated that such sheet will be further fabricated by spinning, drawing, stamping, or forming. Anisotropy of physical properties caused by the preferred orientation developed in the sheet during rolling may be expected to affect the behavior of the metal when subjected to these fabricating operations. To produce a sheet which will be most amenable to the fabrication of a given shape by a particular operation, consideration should be given to the directions and magnitudes of plastic deformations produced in the operation. When possible, the rolling schedule should be controlled to develop a texture which favors the required deformation. The existence of preferred orientations in rolled molybdenum sheet has been reported by Jeffries,' Konobejewsky,' Fujiwara," Goss,' and Ransley and Rooksby." None of these investigators obtained sufficient X-ray data to permit the construction of pole figures; instead, they based their conclusions upon Debye-Scherrer patterns of a limited number of positions. Ransley and Rooksby devoted some attention to transcrystalline cleavage at 45" to the rolling direction, indicating that it is appreciable in polycrystalline material only when the crystals are in the ideally preferred condition, and that this condition is only approached if the metal has been rolled successively in two perpendicular directions. In a recent paper, Custers and Riemersmao introduced the first pole figures to describe the textures of straight-rolled and cross-rolled molybdenum sheet. To increase the knowledge concerning the generation and effects of preferred orientations in molybdenum sheet, an investigation was undertaken to determine the effects of variations in rolling schedule and annealing treatments on preferred orientation, and to correlate preferred orientations with some mechanical properties. The orientations of straight-rolled, cross-rolled, and compression-rolled sheet have been determined by X-ray analysis, both as-rolled and after recrystallization. Pole figures have been constructed to describe the textures produced by these various rolling procedures. Texture of Cast Molybdenum Ingots In the arc-cast process, molybdenum powder is pressed into a vertical column which is sintered to increase its strength as it proceeds downward into a water-cooled mold, where the metal is melted in an alternating-current arc established between the end of the formed powder electrode and the metal bath at the top of the growing ingot. Since the solid-liquid interface moves continuously upward in the mold, the crystal axes are not normal to the cold surface of the mold but have the curvature shown in Fig. la. X-ray analysis reveals that the cube axis is the fiber axis and that it is normal to the cold surface of the mold; that is, the [loo] direction is parallel to the longitudinal axis of the ingot. This substantiates recent work by

Jan 1, 1953

By W. A. Wall, R. L. Kidd

IN present-day flotation practice, grinding of the flotation feed is carried to extremely fine sizes, 70 to 80 per cent minus 200 mesh being customary. The greatest flotation losses occur in the coarsest and finest sizes, but the losses in the very fine sizes are, of course, much the more important because of the large proportion of fines in the feed. These losses are particularly high in zinc ores so a study of the effect of size on the flotation of sphalerite has been made. The mineral used in these experi¬ments was a pure sphalerite, especially free from copper, from the Joplin district in Missouri. The sizes coarser than 200 mesh were separated by screening, the sized mineral then being deslimed on a Wilfley table. The sizes finer than 200 mesh were obtained by water elutriation as described by H. R. Bradford (M. S. Thesis, University of Utah, 1932) ; particles finer than 6.5 microns could not be obtained with the apparatus used.

Jan 1, 1933

By D. B. Kibler

Pill Florida hard-rock field extends from Suwanee and Columbia Counties in northwest Florida to south of Croom, Florida, in Hernando County this area is approximately 100 miles long and varies from 2 to 30 miles 1n width Florida hard-rock phosphate was discovered at Hale Springs, about one mile northwest of the town of Dunnellon Marion County, in the year 1888, by Albertus Voight who lived within a few hundred yards of the spring Soon after this discovery there was a great influx of land speculators and wildcat operators into the vicinity of Dunnellon A few years later phosphate was found in Alachua, Levy, Citrus and Hernando Counties, and a great number of small crude plants were built from Newberry, Alachua County, all the way to Croom, Hernando County Phosphate was found in many places as "outcrops " Looking for outcrops was the first method used by the early prospectors in searching for deposits Several years passed before any systematic method of prospecting was used EARLY MINING The early method of mining hard-rock phosphate was with picks and shovels, wheelbarrows, mules and wagons The pick-and-shovel method was used altogether until about 1900, when some of the larger operators began to use railroad-type steam shovels of from 1/2 to 1-yd capacity Picks and shovels, with negro labor loading the phosphate ore (called "matrix") into wooden side-dump skip-cars, was continued until about 1907 From the discovery of hard-rock phosphate until approximately 1905, overburden was removed with mules and scrapers At some places, the overburden was loaded into side-du nip skip-cars by negro laborers and the cars were then pulled up an incline with a steam hoisting engine The maximum depth of overburden that could be economically removed by hand labor mules and scrapers was approximately 15 feet About 1905 one of the companies erected a producer-gas powerhouse near Dunnellon and generated its own electricity and about the same time the larger companies began using hydraulic methods for the removal of overburden From the year 1888 through the year 1939, approximately 75 companies were operating at one time or another in the hard-rock territory, on approximately 500 locations The hard-rock deposits are more irregular and have higher mining costs than the pebble-rock deposits, therefore they have not been competitive in the domestic market, but because of the higher grade of the hard rock it is in demand for the export trade Discovery of phosphate outside of the United States has made it increasingly difficult in recent years for the hard-rock companies to survive, so today only three companies are operating These

Jan 1, 1941

By W. Rostoker, R. P. Elliott, B. W. Levincer

Phase equilibria in the Ti-Cr-Mo system have been investigated for alloys containing 100 to 40 pct Ti in the temperature range 550° to 1300°C. Five experimental isothermal sections and a surface of incipient melting are presented in addition to a summary projection of the space. Seven vertical sections have been constructed from the isothermal sections. A STUDY of the system Ti-Cr-Mo was undertaken as part of a program sponsored by Watertown Arsenal toward the development of titanium-base phase equilibrium diagrams of potential technical importance to alloy development. The scope of the investigation included the composition range contained by the titanium corner and the line of 64 pct Ti (all compositions are by weight) and the temperature range 550" to 1100°C. A surface of incipient melting was constructed from measurements on a large number of alloys. The system Ti-Cr has been established.&apos;-? The phase diagram is characterized by a wide miscibility field of the solid solution at elevated temperatures and a eutectoid reaction of the type: (15 pct Cr) + TiCr, (685C). The a solid solution has a very limited capacity for solution of chromium (< 0.5 pct Cr). The intermediate phase TiCr2 has at best a very narrow composition range. It has been shown that two allotropic modifications of this phase exist. However, this behavior does not appear to be perceptibly reflected in the form of phase boundaries of the type + TiCr,. In the system Ti-Mo,9-10 the phase is stabilized to successively lower temperatures with increasing molybdenum content. There are no known intermediate phases. The a solid solution is limited to less than 0.5 pct Mo. Because of the very extensive range of the phase, the ternary system was ideally suited to the determination of the phase boundaries by the parametric method of Andersen and Jette." A parametric surface was constructed to provide the necessary basis for the application of this method. Preparation and Treatment of Alloys More than 60 alloy compositions were prepared for the study of this system. Alloy buttons of 10 grams were arc-melted in a nonconsumable electrode furnace using inert atmosphere protection and a water-cooled copper crucible. The construction and operation of this type of melting unit have been adequately described elsewhere.&apos;&apos; To insure complete solution of alloy additions, the buttons were remelted alternately on top or bottom as many as five times. This was accomplished by a suitable mechanism for "flipping" over the ingots. Iodide titanium (99.97 pct Ti) was used as the alloy base. An especially high quality chromium (99.9 pct Cr) was obtained from the National Research Corp. Molybdenum sheet (0.005 in.) of 99.9 pct purity was used.

Jan 1, 1954

By S. F. Shaw

Fox some time it has been more or less recognized within the industry that a scientific control of flowing wells would result in increased production and a greater ultimate recovery of oil. About two years ago it was proposed by the writer that this control should follow principles worked out by him while handling large air-life operations. In the case of wells that had ceased to flow where a large quantity of liquid was present, the use of these principles would result in a large increase of production by using compressed air or gas to flow the well; in the case of a well flowing naturally it would take the form of controlling the gas associated with the oil, resulting either in immediate increase of production or in a reduction of the gas consumed per barrel of oil, and in both cases would result in a greater ultimate recovery from the sand. The Roxana Petroleum Corp., appreciating the advantages to be obtained by a scientific application of the principles of the air lift to oil wells, recently engaged, for a limited time, the services of the writer to work out some of the problems involved. The work was carried out at Braman, Garber and Tonkawa in Oklahoma, and at Oxford in Kansas. Following some suggestions of the writer a well was also equipped by the Roxana company at Smackover by A. S. Field.

Jan 11, 1926

By D. K. Deardorff, Earl T. Hayes

An improved technique is described for the accurate determination of melting points of metals in the temperature range 1500&apos; to 2500°C. The improvements consist of gradient heating and refinements in cavity preparation to obtain true black-body conditions. The melting point of hafnium, as determined by this method, is set at 2222°±30°C. This is over 200°C higher than one of the values reported earlier. Discrepancies in the previously reported values for the melting point of hafnium are explained. The melting points of zirconium and titanium are found to be 1855O±15OC and 1668°±10°C, respectively. Reproducibility of results was ±3OC. PRIMARILY, this report is being made to correct a 1975o±25oC1 value for the melting point of hafnium, and to present an improved method for melting point determination. As a matter of interest, the technique was also applied to determining the melting point of zirconium and titanium. There is a wide difference in the melting point of hafnium as reported by competent investigators. DeBoer and Fast&apos; reported a value of 2230°±500C, and later work of McPherson, as reported by Aden-stedt, placed the melting point at 1975o±25oC. Zwikker" calculated that the melting point was 2430°C. In resolving this discrepancy, improvements were made in the procedure for determining the melting points of refractory metals in the range 1500" to 2500°C. Special techniques are necessary to determine the melting point of these metals accurately. Since the metals oxidize in air above 900oC, the determinations must be carried out in an inert gas or vacuum. Also, every known refractory contaminates them to some extent. In addition, the attainment of true black-body conditions is always difficult. DeBoer and Fast actually determined the melting point of Hf-Zr as-deposited iodide process alloys and extrapolated to 100 pet Hf. McPherson employed a tungsten wire suspension similar to that described by Schramm, Gordon, and Kaufmann,1 and used hafnium metal produced by the iodide process. There was no apparent reason for the wide spread in melting points, since the quality of the metal was very good and the work was under the direction of highly competent investigators. Retracing some of this work revealed one understandable error in the case of hafnium, and led to development of an improved technique for determining melting points of reactive metals in the range 1500" to 2500°C. Material Crystal bar hafnium, zirconium, and titanium were used for this work, with analyses as shown in Table I. The hafnium was of the highest purity that has been prepared, though not as pure as the zirconium and titanium. At the instigation of the Pittsburgh Area Office of the AEC, a special lot of Hfo2 was purified, converted to the tetraflouride, and bomb-reduced with calcium, all at the Iowa State College Laboratories. This crude hafnium metal was then refined by the iodide process at the Foote Mineral Co. All specimens were cut with a Sic wheel, ground, pickled, and dried carefully before use. Procedure General Tungsten Suspension Method—In this method, a small specimen is suspended by a fine tungsten wire in a slender, induction-heated tungsten or tantalum cylinder, all under vacuum. The melting point is determined by heating the specimen slowly while observing it with an optical pyrometer focused upon a portion of the specimen that radiates as a black body. This means that there should be no reflected radiation, either from colder objects near the pyrometer or from hotter surfaces. The induction heater would be the only hotter object and, if it is slender enough, the specimen will attain the same temperature. Often a slender hole is drilled into the specimen as a source of black-body radiation. This was the general method used by McPherson in obtaining his value of 1975°C for the melting point of hafnium. In trying to repeat this work, it was found that the points of contact between the

Jan 1, 1957

By Samuel L. Hoyt

THIS paper gives a short account of plastic deformation as observed in single crystals of zinc, zinc having been selected for the experiments described herein because the phenomena are comparatively so simple and can be studied throughout such a wide range. It is hoped that the paper will serve to show the type of information which studies of single crystals afford and will contribute toward the solution of the general problem of metallic behavior. PRODUCTION OF ZINC SINGLE CRYSTALS The method of Czochralski,1 as modified by von Gomperz,2 was used to produce the crystals studied. The equipment is shown in Fig. 1. Molten zinc is held in a crucible at a temperature which is not far above its melting point, as measured by a pyrometer. A lava disk floats on ,the melt, and is provided with a central hole about 1 mm. in diameter. A glass tube, drawn into a capillary at the lower end, is suspended from a string which is wound up by an electric drive at the speed desired. At the start, the glass capillary is let down into the melt and the hoist is started.. The capillary brings up a small quantity of molten metal with it to a point just above the lava disk. At this point, a jet of hydrogen cools it and causes it to crystallize, with the result that a small crystal forms. As the hoisting is continued, more molten metal is drawn up, in turn to be solidified by the jet of hydrogen. This additional metal continues the growth of the crystal already formed, and a long, cylindrical crystal results. The speed of hoisting used was generally between 0.1 and 0.5 mm. per sec., and the crystals were from 4 to 6 in. long and about 1 mm. in diameter. By varying the conditions, crystals of quite different orientations were obtained and were used in the study of the phenomena to be described.

Jan 1, 1927

By E. P. Klier

The work of Klier and Lyman1 on the bainite reaction has led to the full description of this reaction for medium-carbon low-alloy steels. Certain experimental data reported by Klier and Lyman appear, however, to be improbable of obtaining in very high-carbon steels. The study herein reported consists of an analysis of the transformation characteristics of a 3 per cent chromium, I per cent carbon steel by means of X-ray and metallographic methods. From the results obtained it is concluded that the bainite reaction in this steel is more complicated than that reported by Klier and Lyman for the low-carbon low-alloy steels. Henever, the mechanism of bainite formation in this steel appears to be essentially the same as proposed for the low-carbon low-alloy steels with the modification that the first volumes to transform are carbon-rich rather than carbon-poor. Experimental Procedure The analysis of the steel studied was: Cr, 2.89; C, 1.02; Mn, 0.33; Si, o.35; S, 0.012; P, 0.020. The stock was received from the Carpenter Steel Co. in rolled bars. Specimen Preparation Specimens were austenitized at 1200°C. (2192°F.) for 25 min. in purified nitrogen. The resultant A.S.T.M. austenite grain size was 0-1. Isothermal transformation was allowed by quenching the specimens into liquid metal baths controlled to 5°C. at 540°C. (1004°F.) and above, and to 2°C. at 490°C. (914°f.) and below. Following the desired degree of transformation all specimens were water quenched. Metallographic Examination Specimens 1/4 in. round by 1/4 in. were used for nietallographic examination. Etch-ants used were Vilella&apos;s reagent (I gram picric acid, 10 ml. hydrochloric acid to make 100 ml. ethyl alcohol solution) and alkalinc sodium picratc (electrolytic). Vilella&apos;s reagent was effective in revealing all microconstitucnts, while the alkaline sodium picrate developed the carbon-rich structures or carbides only. X-ray Examination Two X-ray techniques were used—the Debye-Scherrer method and a back-reflection method. &apos;The small specimens necessary for the Debye-Scherrer method were austenitized and then allowed to transform, or were cut from the larger metallographic specimens. The metallographic specimens were used for the back-reflection X-ray analysis. When it was desirable to determine the structure of the carbide present, sliver specimens were electrolytically etched to develop a carbide coating, then were exposed in the cameras. This technique was frequently necessary to allow positive identification of the carbide.

Jan 1, 1945

By E. V. Potter, H. C. Lukens

THE volume of hydrogen released from electrolytic manganese at various temperatures and pressures was determined in a previous investigation1 as part of a study to determine the most practical procedure for removing the hydrogen from electrolytic manganese metal. No attempt was made to determine the absolute volume of gas in the metal at any temperature and pressure; the volume of gas released showed only the variation in solubility with temperature and pressure. The results were very similar to those obtained by Sieverts and Moritz.2 Both sets of data show a minimum solubility between 500° and 700°C., but they differ in certain respects; on cooling from 500°C., our results showed an increase in solubility of about 7 C.C. as compared with an increase of 34 C.C. per 100 grams shown by Sieverts. Furthermore, the transition temperatures, as indicated by sharp breaks in the solubility curves, did not agree well with Sieverts&apos; data. This information was of secondary importance in the earlier investigations, and the solubility at low temperatures and the transition temperatures were subject to considerable error. There- fore, a subsequent investigation, reported in this paper, was made to measure the absolute solubility at temperatures from room temperature through the melting point and make more accurate observations of the transition temperatures. APPARATUS AND METHOD The apparatus and method were essentially the same as those described in the previous work,1 as shown in Fig, I. At high temperatures, the small tube containing the thermocouple in the sample container A frequently broke off, so for some of this work the thermocouple was placed outside the sample container and protected by a quartz tube of about the same wall thickness as the sample container. No significant difference was found in the transition temperatures obtained in the two ways. The automatic temperature controller was used in these tests in the regions where there was little change in solubility with temperature. In the neighborhood of the transition points a continuously variable autotransformer was used instead of the automatic controller, and the power input to the furnace was adjusted so that the temperature increased or decreased at a very slow, uniform rate through the transition range. This procedure was followed because the temperature oscillations produced by the controller were too great compared with the transition range, and the transition points determined under such conditions were less accurate. ABSOLUTE SOLUBILITY Procedure and Results The absolute solubility of hydrogen in manganese could be determined most

Jan 1, 1946

By Gerald V. Jergensen

Does an idea have merit? What does it cost to implement? Can the concept be implemented successfully? The ultimate proof is to try, then see. However, when there are many millions of dollars at stake, blindly building and trying requires considerable courage. Owners and investors in retrospect might choose other less complimentary words. So we might ask, "How might we establish the feasibility of an idea or concept before committing large sums of money to the ultimate test?" From this basic and prudent question, has evolved the engineering concept of the feasibility study. A feasibility study is simply a systematic evaluation of an idea or concept to determine the prospects for success. In a literal sense, a feasibility study considers an idea in terms of its data base, "builds" the idea on paper, "operates" that idea, calculates the cost and benefits, then measures the probable success in terms of some economic, technical or financial standard. Feasibility studies can be quite modest in scope yet provide useful insights as to the viability of an idea. A study might be initiated only to examine the completeness or validity of the metallurgical data base. Another study could be a search for a workable idea or solution to an already-identified possibly troublesome problem. In this latter case, the question, "Will it work?" may be far more important than, "How much will it cost?" Feasibility studies are sometimes global in scope, involving several dozens of specialists and examining an entire "grass roots" mining complex. Other studies may be less ambitious but equally important in examining an expansion proposal or developing new operating techniques. Studies may be commissioned to remove plant bottle-necks, solve maintenance problems and so on. The terms study and feasibility study are used interchangeably in this chapter. They denote a systematic method to examine a proposed concept or idea. DATA BASE Typically, studies are initiated with a minimum amount of specific information and a maximum number of assumptions. As the work proceeds and the data base expands, assumptions are replaced

Jan 1, 1982

By H. C. Lukens, E. V. Potter

The volume of hydrogen released from electrolytic manganese at various temperatures and pressures was determined in a previous investigation1 as part of a study to determine the most practical procedure for removing the hydrogen from electrolytic manganese metal. No attempt was made to determine the absolute volume of gas in the metal at any temperature and pressure; the volume of gas released showed only the variation in solubility with temperature and pressure. The results were very similar to those obtained by Sieverts and Moritz.² Both sets of data show a minimum solubility between 500&apos; and 700°C., but they differ in certain respects; on cooling from 500°C., our results showed an increase in solubility of about 7 C.C. as compared with an increase of 34 C.C. per 100 grams shown by Sieverts. Furthermore, the transition temperatures, as indicated by sharp breaks in the solubility curves, did not agree well with Sieverts&apos; data. This information was of secondary importance in the earlier investigations, and the solubility at low temperatures and the transition temperatures were subject to considerable error. Therefore, a subsequent investigation, reported in this paper, was made to measure the absolute solubility at temperatures from room temperature through the melting point and make more accurate observations of the transition temperatures. Apparatus and Method The apparatus and method were essentially the same as those described in the previous work,&apos; as shown in Fig. I. At high temperatures, the small tube containing the thermocouple in the sample container A frequently broke off, so for some of this work the thermocouple was placed outside the sample container and protected by a quartz tube of about the same wall thickness as the sample container. No significant difference was found in the transition temperatures obtained in the two ways. The automatic temperature controller was used in these tests in the regions where there was little change in solubility with temperature. In the neighborhood of the transition points a continuously variable autotransformer was used instead of the automatic controller, and the power input to the furnace was adjusted so that the temperature increased or decreased at a very slow, uniform rate through the transition range. This procedure was followed because the temperature oscillations produced by the controller were too great compared with the transition range, and the transi- . tion points determined under such conditions were less accurate. Absolute Solubility Procedure ad Results The absolute solubility of hydrogen in manganese could be determined most

Jan 1, 1947

By E. V. Potter, H. C. Lukens

The volume of hydrogen released from electrolytic manganese at various temperatures and pressures was determined in a previous investigation1 as part of a study to determine the most practical procedure for removing the hydrogen from electrolytic manganese metal. No attempt was made to determine the absolute volume of gas in the metal at any temperature and pressure; the volume of gas released showed only the variation in solubility with temperature and pressure. The results were very similar to those obtained by Sieverts and Moritz.² Both sets of data show a minimum solubility between 500&apos; and 700°C., but they differ in certain respects; on cooling from 500°C., our results showed an increase in solubility of about 7 C.C. as compared with an increase of 34 C.C. per 100 grams shown by Sieverts. Furthermore, the transition temperatures, as indicated by sharp breaks in the solubility curves, did not agree well with Sieverts&apos; data. This information was of secondary importance in the earlier investigations, and the solubility at low temperatures and the transition temperatures were subject to considerable error. Therefore, a subsequent investigation, reported in this paper, was made to measure the absolute solubility at temperatures from room temperature through the melting point and make more accurate observations of the transition temperatures. Apparatus and Method The apparatus and method were essentially the same as those described in the previous work,&apos; as shown in Fig. I. At high temperatures, the small tube containing the thermocouple in the sample container A frequently broke off, so for some of this work the thermocouple was placed outside the sample container and protected by a quartz tube of about the same wall thickness as the sample container. No significant difference was found in the transition temperatures obtained in the two ways. The automatic temperature controller was used in these tests in the regions where there was little change in solubility with temperature. In the neighborhood of the transition points a continuously variable autotransformer was used instead of the automatic controller, and the power input to the furnace was adjusted so that the temperature increased or decreased at a very slow, uniform rate through the transition range. This procedure was followed because the temperature oscillations produced by the controller were too great compared with the transition range, and the transi- . tion points determined under such conditions were less accurate. Absolute Solubility Procedure ad Results The absolute solubility of hydrogen in manganese could be determined most

Jan 1, 1947

By L. D. Wooddy, Robert Moscrip

The simultaneous solution of the volumerric balance and the unsteady-state equation has been used for several years to make performance calculations for combination drive reservoirs. This method makes possible the calculation of volumetric changes of fluids in the gas cap, oil zone, and aquifer which occur as a result of withdrawals and reservoir pressure changes. It does not provide a means for the determination of reservoir fluid distribution changes corresponding to these vollrmetric changes. A knowledge of the fluid saturation distribution in the reservoir at various stages of depletion is important for the determination of the efficiency of gas and water as oil-displacement media and, therefore, for the reliable predicrion of ultimate oil recovery. To provide this knowledge, the displacement equations are solved simultaneously with the volumetric balance and unsteady-state equations. The described calculation procedure has been used satisfactorily to analyze the past performance and to predict the future behavior of combination drive reservoirs under both primary and pressure-maintenance operations. INTRODUCTION The three basic mechanisms by which oil is displaced from a reservoir are: (1) dissolved gas drive—the displacement of oil by the expansion of liberated solution gas, (2) water drive—the displacement of oil by water which enters the oil zone from the aquifer, and (3) gas cap drive—the displacement of oil by gas which ex- pands into the oil zone from the gas cap. The action of gravitational forces may be effective in increasing the efficiency of the basic drive mechanisms. Gravitational forces favor the segregation both of gas and oil and of oil and water, thus tending to shorten the transition zone between oil and displacing fluids. Most reservoirs produce under the influence of a combination of these drives and are designated "combination drive reservoirs". Fig. 1 is a cross section of a typical combination drive reservoir. A calculation procedure for analyzing the performance of combination drive reservoirs has been developed by combining the displacement equations&apos; with the volumetric balance equation&apos; and the unsteady-state equations. The pressure-production performance and the positions of the gas-oil and oil-water contacts are calculated for several stages of reservoir depletion by solving these equations simultaneously, thus affording a basis for: 1. Determining instantaneous and ultimate oil, gas, and water production under various operating conditions. 2. &apos;Establishing a maximum efficient rate of production, 3. Determining the advantages of pressure maintenance and unitization, and 4. Designing surface installations necessary for primarv and pressure-maintenance operations. DEFINITIONS The calculation procedure for combination drive res-

Jan 1, 1957

By R. E. Grace

WHEN an Fe-C alloy, partially reacted to pearl-ite, is quenched rapidly enough to suddenly stop the growth process, it may be expected that any carbon concentration gradients will freeze in situ in the newly formed martensite. A short tempering treatment should precipitate finely dispersed iron carbide particles in approximately the same distribution in which carbon existed during the growth process. Examination with the electron microscope of areas of tempered martensite adjacent to the pearlite-martensite interface should reveal the existence of preferred areas of precipitation. Fig. 1 is an example of an electron micrograph used in this study. Small sections of a commercial steel (0.9 pct C, 1.6 pct Mn, 0.25 pct Si) were austenitized at 945°C in air for 45 min, furnace-cooled to 697°C, iso-thermally reacted to pearlite for 30 min, and quenched into iced brine. Two samples were tempered 5 and 20 min, respectively, in air at 498°C and were subsequently quenched in water. The samples were mechanically polished and etched in 1 pct picral. Collodion replicas were made by the conventional technique; these were shadowed with chromium at about 650&apos; from the horizontal, and electron micrographs were taken at a linear magnification of 14,200X. Prints were made at a magnification of 44,100X. Lineal analysis of the prints was made as a function of the interlamellar spacing and volume percent of iron carbide. Straight lines were drawn into tempered martensite between adjacent lamellae at a distance S/4 or S/6 apart, where S is defined as the interlamellar spacing measured at the pearlite-martensite interface. The volume percent of iron carbide was measured along each of these traces with a "gage length" of S/10. The results of analyses of two samples are shown in Table I. The area included between the S/2 and S distance from the interface could be considered homogeneous within the sensitivity of the measuring technique. This value was used as a proportionality factor to evaluate an arbitrary carbon content of homogeneous austenite, and also as a parameter by which error in measurements could be evaluated. Results of the lineal analysis are shown in Figs. 2 and 3. Fig. 4 shows the statistical nature of the interlamellar spacing for all lamellae measured in this

Jan 1, 1954

By R. K. Buhr, H. Thresh, M. Bergeron, F. Weinberg

The microsegregation of nickel and chromium in directionally solidified AISI 4340 steel castings has been measured using electron probe microanalysis. Minimum concentrations were observed to occur at the center of the dendrite stalks, as reported previously. However, the position of the maximum concentrations could not be determined from the dendrite configuration. An etching technique has been developed which shows the position of maximum concentration. Measurements were made of the distribution of nickel and chromium in the dendritic structure. The ratio of maximum to minimum concentration was determined as a function of primary dendrite arm spacing for both as-cast and partially homogenized materials. The results are compared with observations reported in the literatuve. A S part of an investigation of solute segregation in directionally solidified AISI 4340 steel casting, electron probe microanalysis was used to measure the distribution of nickel and chromium in the dendritically segregated material. This complemented the observations on the segregation of radioactive phosphorus obtained by autoradiographic techniques in the same castings.&apos; Kattamis and I?lemings2 have reported similar measurements, using electron probe microanalysis, on dendritically segregated AISI 4340 steels. They found minimum solute concentrations occurred at the center of dendrites, maximum concentrations occurred in the center of interdendritic regions, for symmetrically oriented dendrites, and a regular variation of concentration within dendrite arms. The ratio of maximum to minimum concentration was found to be essentially independent of position in the castings, except near the chill surface where it was somewhat higher. Assuming complete diffusion in the liquid and no diffusion in the solid during freezing, they considered that isoconcentration curves in the steel were homothetic. As a result, isoconcentration curves of the various elements, contour surfaces of dendrites produced by isothermal-transformation studies, and the contour of the solid-liquid interface would all be similar, and could be superimposed by a uniform expansion or contraction of the contours. Preliminary results of the present investigation suggested that isoconcentration curves were not homothetic. It was also evident that points of maximum concentration could not be predicted from the dendrite configuration. Since the ratio of maximum to minimum concentration appeared to be an important parameter in defining the overall segregation in a casting, other techniques for determining the point of maximum concentration were investigated. In addition the overall solute distribution associated with the dendritic structure was examined for both nickel and chromium, and the consistency of the distribution for neighboring dendrites was determined. METHOD Fifty-pound heats of AISI 4340 steel were cast in a manner similar to that used by Flemings et al3 with a water-cooled copper base plate and exothermic sides and top. The nominal composition of the material was C, 0.41 pct; Mn, 0.66; Si, 0.35; S, 0.012; P, 0.010; Ni, 1.88; Cr, 0.95; Mo, 0.28. The steel solidified directionally from the chill surface, with a dendritic structure which increased in dendrite arm spacing with increased distance from the chill. Results of the general investigation of the cast structure and segregation of radioactive phosphorus in these castings have been reported elsewhere.&apos; For the present measurements, sections were cut from the casting at several distances from the chill surface. The sections were subsequently heat-treated, mounted, and then polished on a plane perpendicular to the general freezing direction of the casting. Electron probe microanalysis was carried out with the JEOL-JXA3 microprobe using a voltage of 25 kev and beam current of 0.15 µa. The take-off angle is 22 deg. Quartz crystals were used in the spectrometers and measurements made for Ka radiation from both nickel and chromium simultaneously. A thin layer of carbon was deposited on all specimen surfaces prior to examination in the microprobe. Early measurements were made on polished surfaces, with indentation marks produced by a hardness tester to indicate the area of interest. It was found desirable to use etched surfaces, as opposed to polished surfaces, to reduce sample preparation time and more readily relate the microprobe scan to the structure. To determine if this could be done, without introducing significant errors, a series of measurements were made on polished and etched surfaces of the same specimen. Both polished and etched surfaces produced similar results within normal scatter as shown in the observations. Subsequent measurements were then made on etched surfaces. Measurements with the microprobe analyzer were made by point counting, for periods of 100 sec, at 10-µ intervals. Ten-second counts were made on pure nickel and chromium standards, incorporated in the specimen mount before and after each set of measurements. The results were adjusted for background, then corrected for dead time using the expression:

Jan 1, 1969

By Donald W. Scott, Nathaniel Arbiter, A. C. Richardson

This paper describes the application of amine flotation to a specific problem—that of increasing the grade of magnetite concentrates derived from an iron ore requiring extremely fine grinding for mineral liberation. Experiments conducted on an iron ore from Wisconsin had shown that concentrates containing 60 to 62 per cent iron and 12 to 14 per cent silica could be produced by magnetic separation. The residual silica occurred as quartz and hornblende, either entrained or locked with magnetite. Most advantageous utilization of the concentrate, however, necessitated that the silica content be reduced to about 5 per cent, equivalent to an iron content of 67.5 per cent. It had been demonstrated that tabling of the magnetic concentrate removed sufficient quartz and hornblende to yield an acceptable concentrate, but disadvantages inherent in tabling dictated that flotation be investigated as a substitute. The goals set for the flotation investigation were: (I) the production of concentrates of about 68 per cent iron content from the magnetic concentrate; (2) an iron recovery of about 85 per cent of that in the feed to flotation; and (3) minimum reagent cost. Both batch and continuous flotation tests were employed; the former, to establish the procedure and the latter to verify it. Although the data were obtained on a specific ore, and with a commercial application in view, it is believed that they have a bearing on other problems where amine flotation is being used or is anticipated. Samples Two samples, designated "(minus 100-mesh magnetic concentrate" and "minus 150-mesh magnetic concentrate," were used for the batch experimental work. They differed only in the degree to which the crude ore was ground prior to magnetic separation. They were stored moist in steel drums in quantities sufficient for all the experimental work reported. This procedure had the advantage of allowing all tests to be made on common samples, but had the disadvantage that the individual flotation samples, because of the difference in storage time, were subject to various stages of surface alteration. Previous work had indicated that common samples were desirable for the batch studies, and it was decided that if these data appeared sufficiently promising the effect of surface alteration could be checked best by continuous tests. The size distributions and the assays of the samples are given in Table I. The minus 150-mesh magnetic concentrate, on which most of the flotation tests were made, assayed 60.9 per cent iron, 13.3 per cent silica, and 0.016 per cent phosphorus. The minus 325-mesh portion represented 78.I per cent of the sample by weight, and assayed 67.9 per cent iron. Thus, the insoluble, mainly silica, was concentrated

Jan 1, 1947

By Donald W. Scott, Nathaniel Arbiter, A. C. Richardson

This paper describes the application of amine flotation to a specific problem—that of increasing the grade of magnetite concentrates derived from an iron ore requiring extremely fine grinding for mineral liberation. Experiments conducted on an iron ore from Wisconsin had shown that concentrates containing 60 to 62 per cent iron and 12 to 14 per cent silica could be produced by magnetic separation. The residual silica occurred as quartz and hornblende, either entrained or locked with magnetite. Most advantageous utilization of the concentrate, however, necessitated that the silica content be reduced to about 5 per cent, equivalent to an iron content of 67.5 per cent. It had been demonstrated that tabling of the magnetic concentrate removed sufficient quartz and hornblende to yield an acceptable concentrate, but disadvantages inherent in tabling dictated that flotation be investigated as a substitute. The goals set for the flotation investigation were: (I) the production of concentrates of about 68 per cent iron content from the magnetic concentrate; (2) an iron recovery of about 85 per cent of that in the feed to flotation; and (3) minimum reagent cost. Both batch and continuous flotation tests were employed; the former, to establish the procedure and the latter to verify it. Although the data were obtained on a specific ore, and with a commercial application in view, it is believed that they have a bearing on other problems where amine flotation is being used or is anticipated. Samples Two samples, designated "(minus 100-mesh magnetic concentrate" and "minus 150-mesh magnetic concentrate," were used for the batch experimental work. They differed only in the degree to which the crude ore was ground prior to magnetic separation. They were stored moist in steel drums in quantities sufficient for all the experimental work reported. This procedure had the advantage of allowing all tests to be made on common samples, but had the disadvantage that the individual flotation samples, because of the difference in storage time, were subject to various stages of surface alteration. Previous work had indicated that common samples were desirable for the batch studies, and it was decided that if these data appeared sufficiently promising the effect of surface alteration could be checked best by continuous tests. The size distributions and the assays of the samples are given in Table I. The minus 150-mesh magnetic concentrate, on which most of the flotation tests were made, assayed 60.9 per cent iron, 13.3 per cent silica, and 0.016 per cent phosphorus. The minus 325-mesh portion represented 78.I per cent of the sample by weight, and assayed 67.9 per cent iron. Thus, the insoluble, mainly silica, was concentrated

Jan 1, 1947

By Orville R. Lyons

DISCUSSION Judson S. Hubbard (The Humphreys Investment Co., Denver)—In this very interesting paper several brief references are made to the Humphreys spiral, a device used for cleaning fine coal. In Table I, Plants 76 and 77, data are given on spiral performance treating Raton and Trinidad coal. The fine coal, as fed to the spiral in these instances, is actually a table middling, hence the more easily treated material was previously removed and a large number of particles were present which were difficult to clean. Mr. W. M. Bertholf of the Colorado Fuel and Iron Co. presented a paper in February, 1946, Cleaning Table Middlings from a Coal Washery with the Humphreys Spiral Concentrator, from which I quote: "In considering the results of our tests it should be noted that the feed was our table middling, and that any real separation is a &apos;moral victory&apos; as there is little material that could properly be called coal and practically no heavy rock, the consequences being that previous attempts to clean the middling have not at all been successful." Referring again to Table I, Plants 72, 73, 74, and 75, these data were obtained by Yancey and Geer and others and presented at the February 1950 Meeting, AIME, in a paper entitled Laboratory Performance Tests of the Humphreys Spiral as a Cleaner of Fine Coal. Results shown for those tests involve all particles from 8 mesh through the colloids, which admittedly is not an ideal situation for spiral feed if much refuse is contained in the —80 mesh or —100 mesh size range. As an illustration of the effect of treating too broad a size range, let us consider Plant No. 75, Kentucky No. 9 seam. Spiral feed was 8 mesh x 0. Now had this been 8x100 mesh the percentage of misplaced material would have been 8.0 pct instead of the reported 15.26 pct. Similar comparisons can be made on the other data presented with respect to the spiral. Other types of equipment show a similar trend in that whenever too fine a size is treated in a given unit process the percentage of misplaced material increases. Since the spiral is working near the finer end of the size range, it will sometimes be advantageous to treat the entire range of —8 mesh material rather than to deslime and make a fair showing on, say, the +80 or + I00 mesh. Desliming is subsequently done in any case in the dewatering or thickening operation. Results obtained by spiraling any given coal depend on factors too numerous and complex to discuss here, but there are strong indications that proper preparation of feed to the spiral can improve results obtained on some of the raw coals tested. This is clearly pointed out at the end of the aforementioned paper by Yancey and Geer. "The spiral is an extremely simple device which involves no moving parts and is constructed almost entirely of unmachined castings. Since it is such an uncomplicated mechanism, operation is simple and virtually foolproof. These characteristics, which go far toward insuring low cost operation, are attractive attributes in any coal cleaning unit." Certain equipment used in conjunction with the spiral has resulted in a decrease in the percentage of misplaced material, notably in actual practice the launder screen which is used to remove objectionable high ash fines from a spiral-washed coal product. Private correspondence with the U. S. Bureau of Mines has intimated that an additional yield of coal is possible by flotation of the spiral middling. Possible future improvements and developments may result from other methods now under consideration. Finally, some compromise must be made between the best metallurgical performance and the best practical or economical results. Mr. Lyons emphasizes in his summary this objective of overall economy in selection of equipment. G. B. Walker (American Cyanamid Co., Stamford, Conn.)—I had the pleasure of reviewing the draft of this paper and my curiosity was aroused by the data given for Tromp plants, in that all of the examples shown appeared to be 2-product separations, whereas all the Tromp plants with which I am familiar have been 3-product units. The data given for plants No. 101 and 102 appear to be taken from Tromp&apos;s brochure on his process and represent the results obtained at the Dominale plant in Holland which was operated for many years by Mr. Tromp. The plant, which was designed to treat 58 tons per hr, was sampled while treating 35 tons per hr of 3Y4x-in. coal. Example 101 appears to conform to what would result if the middling product were calculated into the refuse product, while Example 102 represents the calculation of the middling into the coal product. It is believed that Examples 103 and 104 represent the operation of the Willem-Sophie Mine in Holland recalculated on the same basis. In checking the English examples given by numbers 14, 15, 16, and 17, the same procedure seems to have been followed. These results have, apparently, been taken from an article in Colliery Engineering in August 1941, describing the initial operation of the Williamthorpe Colliery of the Hardwick Colliery Co. Two vessels are employed in this plant, one to treat soft coal and one to treat hard coal. Example No. 14 presents the results that could be obtained from the soft coal bath if the middling were calculated into the refuse, and Example 15 the results when the middling is calculated into the coal. Examples 16 and 17 represent the same expedient in the case of the hard coal bath. Of interest to this discussion is the fact that during the past year the Simon-Carves Engineering Co. in England has installed in the Williamthorpe plant their new "Sim-Car" medium cleaning system which is based on magnetic extraction and control and which is licensed under the Heavy-Media Separation Processes patents by the American Zinc, Lead and Smelting Co. This system has been described in the December 1951, issue of Colliery Engineering. It is reported that since the Williamthorpe Colliery was changed from the Tromp system of medium cleaning to the Magneto-Motive method of medium control the opera-

Jan 1, 1953

By Orville R. Lyons

DISCUSSION Judson S. Hubbard (The Humphreys Investment Co., Denver)—In this very interesting paper several brief references are made to the Humphreys spiral, a device used for cleaning fine coal. In Table I, Plants 76 and 77, data are given on spiral performance treating Raton and Trinidad coal. The fine coal, as fed to the spiral in these instances, is actually a table middling, hence the more easily treated material was previously removed and a large number of particles were present which were difficult to clean. Mr. W. M. Bertholf of the Colorado Fuel and Iron Co. presented a paper in February, 1946, Cleaning Table Middlings from a Coal Washery with the Humphreys Spiral Concentrator, from which I quote: "In considering the results of our tests it should be noted that the feed was our table middling, and that any real separation is a &apos;moral victory&apos; as there is little material that could properly be called coal and practically no heavy rock, the consequences being that previous attempts to clean the middling have not at all been successful." Referring again to Table I, Plants 72, 73, 74, and 75, these data were obtained by Yancey and Geer and others and presented at the February 1950 Meeting, AIME, in a paper entitled Laboratory Performance Tests of the Humphreys Spiral as a Cleaner of Fine Coal. Results shown for those tests involve all particles from 8 mesh through the colloids, which admittedly is not an ideal situation for spiral feed if much refuse is contained in the —80 mesh or —100 mesh size range. As an illustration of the effect of treating too broad a size range, let us consider Plant No. 75, Kentucky No. 9 seam. Spiral feed was 8 mesh x 0. Now had this been 8x100 mesh the percentage of misplaced material would have been 8.0 pct instead of the reported 15.26 pct. Similar comparisons can be made on the other data presented with respect to the spiral. Other types of equipment show a similar trend in that whenever too fine a size is treated in a given unit process the percentage of misplaced material increases. Since the spiral is working near the finer end of the size range, it will sometimes be advantageous to treat the entire range of —8 mesh material rather than to deslime and make a fair showing on, say, the +80 or + I00 mesh. Desliming is subsequently done in any case in the dewatering or thickening operation. Results obtained by spiraling any given coal depend on factors too numerous and complex to discuss here, but there are strong indications that proper preparation of feed to the spiral can improve results obtained on some of the raw coals tested. This is clearly pointed out at the end of the aforementioned paper by Yancey and Geer. "The spiral is an extremely simple device which involves no moving parts and is constructed almost entirely of unmachined castings. Since it is such an uncomplicated mechanism, operation is simple and virtually foolproof. These characteristics, which go far toward insuring low cost operation, are attractive attributes in any coal cleaning unit." Certain equipment used in conjunction with the spiral has resulted in a decrease in the percentage of misplaced material, notably in actual practice the launder screen which is used to remove objectionable high ash fines from a spiral-washed coal product. Private correspondence with the U. S. Bureau of Mines has intimated that an additional yield of coal is possible by flotation of the spiral middling. Possible future improvements and developments may result from other methods now under consideration. Finally, some compromise must be made between the best metallurgical performance and the best practical or economical results. Mr. Lyons emphasizes in his summary this objective of overall economy in selection of equipment. G. B. Walker (American Cyanamid Co., Stamford, Conn.)—I had the pleasure of reviewing the draft of this paper and my curiosity was aroused by the data given for Tromp plants, in that all of the examples shown appeared to be 2-product separations, whereas all the Tromp plants with which I am familiar have been 3-product units. The data given for plants No. 101 and 102 appear to be taken from Tromp&apos;s brochure on his process and represent the results obtained at the Dominale plant in Holland which was operated for many years by Mr. Tromp. The plant, which was designed to treat 58 tons per hr, was sampled while treating 35 tons per hr of 3Y4x-in. coal. Example 101 appears to conform to what would result if the middling product were calculated into the refuse product, while Example 102 represents the calculation of the middling into the coal product. It is believed that Examples 103 and 104 represent the operation of the Willem-Sophie Mine in Holland recalculated on the same basis. In checking the English examples given by numbers 14, 15, 16, and 17, the same procedure seems to have been followed. These results have, apparently, been taken from an article in Colliery Engineering in August 1941, describing the initial operation of the Williamthorpe Colliery of the Hardwick Colliery Co. Two vessels are employed in this plant, one to treat soft coal and one to treat hard coal. Example No. 14 presents the results that could be obtained from the soft coal bath if the middling were calculated into the refuse, and Example 15 the results when the middling is calculated into the coal. Examples 16 and 17 represent the same expedient in the case of the hard coal bath. Of interest to this discussion is the fact that during the past year the Simon-Carves Engineering Co. in England has installed in the Williamthorpe plant their new "Sim-Car" medium cleaning system which is based on magnetic extraction and control and which is licensed under the Heavy-Media Separation Processes patents by the American Zinc, Lead and Smelting Co. This system has been described in the December 1951, issue of Colliery Engineering. It is reported that since the Williamthorpe Colliery was changed from the Tromp system of medium cleaning to the Magneto-Motive method of medium control the opera-

Jan 1, 1953

By A. H. Larson, T. P. McNulty

RECENTLY, an investigation of the absorption of sulfur dioxide gas in molten binary copper alloys was conducted. A Sieverts-type apparatus, consisting of a mercury-filled gas dispensing buret and a mercury manometer, was used initially for determining the volume of gas absorbed as a function of pressure. The equilibration behavior of the alloys studied indicated that the mercury in the gas measuring system was absorbing sulfur dioxide. Owing to the widespread use of mercury as a displacement medium in absorption studies, an investigation was made to determine the nature and magnitude of the mercury - sulfur dioxide absorption effect. The gas measuring system was modified by substituting a Worden Quartz Products Type PDHV fused-quartz-spiral pressure gage for the mercury-filled dispenser and manometer. The dispensed gas volume at known temperature and atmospheric pressure was measured by evacuating a Pyrex vessel of known volume and by admitting sulfur dioxide into the vessel until the attached quartz pressure gage registered atmospheric pressure. Atmospheric pressure was measured concurrently with a separate mercury barometer. The volume of the empty sample chamber and its attendant apparatus was determined by measuring the equilibrium pressure accompanying the addition of a measured volume of sulfur dioxide into the initially evacuated system. The volume of the mercury sample was calculated from the density of mercury at the temperature of the study (25°C). Measured volumes of sulfur dioxide were then dispensed into the system and the equilibrium pressure accompanying each gas addition was determined. From the difference between the system volume and the mercury volume, the number of moles of gaseous sulfur dioxide remaining in the system at each pressure was calculated. The difference between the number of moles of gas dispensed into the system, denoted Enso2: and the number of moles of gas remaining in the system after absorption equilibrium had been attained, denoted nso2(g), was equal to the number of moles of absorbed gas, denoted nSO2. The number of moles of absorbed gas was then converted to absorbed volume, denoted VSo2, in cu cm at stp conditions of (PC and 760 mm Hg. Table I contains calculated values of Snso2, nSo2(g), and VSo2 for different sulfur dioxide pressures. In the original system, denoted Run I, volume limitations of the gas dispensing system prevented absorption studies at equilibrium pressures near atmospheric pressure, so a different gas dispensing system, denoted Run 11, was used for determining the last pressure reading in Table I. The data in Table I are expressed in terms of the absorption of sulfur dioxide in 49.68 cu cm of mercury. In Fig. 1, these data are expressed in terms of the absorption of sulfur dioxide in 100 cu cm of mercury. Since the absorption data plotted in Fig. 1 show a linear relationship, the volume of sulfur dioxide absorbed in mercury is a function of the first power of pressure. The absorption reaction is So2(gas) = SO2 (in Hg) The first-power pressure dependence, coupled with the fact that the sulfur dioxide could be removed from the mercury by applying vacuum, indicated reversible

Jan 1, 1967