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By Rex W. Woods, Morris Muskat

A leastmsquare analysis procedure has been developed and applied for the study of the deviations in estimations of oil in place as given by the material-balance equations. The data used were those obtained from field observations on the Jones sand in the Schuler pool, Arkansas, and the Monroe dolomite in the Reed City pool, Michigan. Possible effects of water intrusion were taken into account by expressing the cumulative water influx in terms of various functions previously proposed in the literature. Formulas were developed and values calculated for the minimum deviations and minimal percentage deviations in the calculated volumes of oil in place from the average values, as could be obtained by suitable choice of the water encroachment and initial gas-cap volume parameters. The results show that the fluctuations in these calculated volumes are very insensitive to the values chosen for the rate of water intrusion and initial gas-cap volume, and hence cannot be safely used in discriminating between spurious values for these parameters and such as actually pertain to the producing reservoirs. Moreover, the exact form of the water-intrusion function seems to have but little effect on the fluctuations in the computed oil in place. Accordingly, it is concluded that the material-balance method does not of itself provide a satisfactory criterion for determining the basic physical unknowns of producing reservoirs or in making conclusive decisions regarding the production mechanism, unless independently established geological control data are available for eliminating unreasonable values for the reservoir parameters, even though they may still satisfy the material-balance formulas. If, however, from core or logging data the initial oil in place and the gas-cap volume can be established in advance, the material-balance formulas can be inverted to find the water intrusion. Moreover, by determining by such calculations the water-intrusion coefficient, the iuture production performance can then be predicted by the aid of the materiaI-balance formulas for specified operating conditions. This type of application may be of particular value in predicting the results of Pressure-maintenance operations. Introduction The evaluation of the forces acting upon an oil reservoir is a problem of considerable interest to the operator as an aid in determining the proper method of operation for the reservoir to obtain an optimum recovery of oil. In many pools, the nature and magnitude of the forces acting upon the reservoir remain unknown until an appreciable amount of ultimate recovery is obtained. To be of value to the operator, a reliable interpretation of reservoir performance should be available in the early life of the pool to permit an optimum plan of operation. Progress has been made in an understanding of reservoir behavior and the importance of the different factors involved. The material-balance method of estimating oil in place has been proposed as a tool in analyzing reservoir-performance problems.l The solution of such problems by this method ordinarily involves two or more unknown values relating to the nature of the reservoir, and the results

Jan 1, 1945

By F. L. Robertson, C. H. Bacon, J. W. Till

A description is given of the development of a process for making low sulphur steel on furnaces fired with 2 1/2 pet sulphur oil. Slag and metal are analyzed at melt. Slag weight is estimated. A simple method for calculating necessary lime additions for making 0.025 and 0.035 pct sulphur steel is given. DURING the last 15 years John Summers & Sons have been confronted increasingly by the problem of producing a low sulphur steel from high sulphur materials. The principles adopted, the processes used, the data collected on a furnace specially set aside to study this problem, and speculation on future developments are dealt with in this paper. This study is limited to two melting shops which make sheet steel only, of the following analysis: C, 0.06 pct; Mn, 0.33; S, 0.04, 0.035, 0.03, and 0.025; and P, 0.02 and 0.015. All the processes described have reference to the manufacturing of this steel and are not necessarily applicable, without modification, to other steels. The raw materials used are given in Table I. Development of Process About 1934, Schenck's work on phosphorus was applied to frame quantitative rules for the removal of phosphorus, with great success. We could however, neither in our own work nor in the voluminous literature, find any assistance to frame quantitative furnace rules to remove sulphur. Perhaps, we should have persevered with Schenck's outstanding chapter on sulphur in The Physical Chemistry of Steelmaking, but we missed the importance of one (Ss) sentence on p. 478. "Evidently this ratio -------- is [S] the important quantity to be considered from the point of view of chemical reaction; it is clear that the sulphur content of the steel alone, as frequently given in the literature cannot suffice for judging the success of the reaction unless special details are given regarding the sulphur charge and the amount of slag."' We were not however very successful in getting values for Schenck's "n" that agreed with (S) arrived at by our direct analysis. [S] In addition to Schenck's work much attention was given to V value. The formula selected for V was: (SCaO) — 1.57 (2 P2O5) (S SiO2) After plotting many charges a curve was obtained, based upon the relationship between the percentage sulphur in the finished steel and V value, Fig. 1. For a long time this was used as standard with about a 60 to 70 pct success on producer-gas fired furnaces, if all uprising scrap was used and no bought scrap used. An inspection of this curve shows clearly that it is not a quantitative manufacturing process, and that it was not sure enough to go to the trouble and expense of doing stage analysis for P,O,,

Jan 1, 1952

By Henry Seltz, Cyril Wells, Hugh J. MacDonald

Several investigators have measured the heat capacity of cementite, using different methods of attack, but the agreement between the values obtained cannot be considered good. Naeserl has made measurements of "average heat capacities" of iron carbide between 1026" and 85" K., using a water calorimeter. His computed true specific heat at 78.1" K. is 11.22 cal. per gram-formula mass, which, if correct, is much too high for any reasonably accurate extrapolation to 0" K. The cementitc used by Naeser was obtained from a steel containing 0.9 per cent carbon, by electrolytically dissolving out the iron in a neutral bath of ferrous chloride. The cementite remained as a coarse, crystalline, gray powder. Andes2 has measured the specific heat of iron carbide, from 102" to 323" K., as it exists in steel. The specific heats of several slugs of steel of known iron carbide content were determined, and the specific heat of the iron carbide (Fe3C) calculated by plotting specific heat versus percentage of carbon, and extrapolating to pure Fe3C (6.7 per cent C). The heat-capacity values for temperatures below 100" K. were obtained by comparing the temperature-specific heat curve for Fe3C to that of Fe. Since the two were very similar in the range examined experimentally and approach more closely at low temperatures, it was assumed that near the absolute zero the form of the curve for Fe3C would be similar to that of Fe. Andes calculates for the entropy of Fe3 C,S298 = 23.55 e.u. The heat of formation of Fe3C has been studied by several workers. Kelley3 has reviewed these measurements and calculations, and selects those of Roth* and Naeser6 as worthy of most consideration. Roth has given AH = 5400 cal. + 30 per cent as a result of his own and other work. Naeser has determined the heat of formation from Fe and different forms of carbon, and for graphite (0) he finds AH = 5600 cal. Kelley accepts the rounded figure AH = 5500 as the heat of formation at 298.1" K., but this value is quite uncertain.

Jan 1, 1940

By Henry Seltz, Hugh J. MacDonald, Cyril Wells

Several investigators have measured the heat capacity of cementite, using different methods of attack, but the agreement between the values obtained cannot be considered good. Naeserl has made measurements of "average heat capacities" of iron carbide between 1026" and 85" K., using a water calorimeter. His computed true specific heat at 78.1" K. is 11.22 cal. per gram-formula mass, which, if correct, is much too high for any reasonably accurate extrapolation to 0" K. The cementitc used by Naeser was obtained from a steel containing 0.9 per cent carbon, by electrolytically dissolving out the iron in a neutral bath of ferrous chloride. The cementite remained as a coarse, crystalline, gray powder. Andes2 has measured the specific heat of iron carbide, from 102" to 323" K., as it exists in steel. The specific heats of several slugs of steel of known iron carbide content were determined, and the specific heat of the iron carbide (Fe3C) calculated by plotting specific heat versus percentage of carbon, and extrapolating to pure Fe3C (6.7 per cent C). The heat-capacity values for temperatures below 100" K. were obtained by comparing the temperature-specific heat curve for Fe3C to that of Fe. Since the two were very similar in the range examined experimentally and approach more closely at low temperatures, it was assumed that near the absolute zero the form of the curve for Fe3C would be similar to that of Fe. Andes calculates for the entropy of Fe3 C,S298 = 23.55 e.u. The heat of formation of Fe3C has been studied by several workers. Kelley3 has reviewed these measurements and calculations, and selects those of Roth* and Naeser6 as worthy of most consideration. Roth has given AH = 5400 cal. + 30 per cent as a result of his own and other work. Naeser has determined the heat of formation from Fe and different forms of carbon, and for graphite (0) he finds AH = 5600 cal. Kelley accepts the rounded figure AH = 5500 as the heat of formation at 298.1" K., but this value is quite uncertain.

Jan 1, 1940

By Thomas E. Howard

Recipient of the 1975 D. C. Jackling Award - "For his vision and initiative in defining, planning, directing, and accomplishing mining research programs; for his leadership in focusing worldwide attention on the need for research to improve underground excavation for mining and civil applications; and for his lecture. . ."

Jan 1, 1976

By Louis Huber

THE Liberty tunnels extend through a very steep hill in Pittsburgh (locally called Mount Washington) for a distance of slightly over a mile. The two tunnels parallel each other and are 59 ft. apart, center to center (Fig. 1). They are for vehicular traffic, and in each there is ample space for two lines of vehicles. Northbound traffic, towards downtown Pitts- FIG. I.-NORTH PORTAL OF LIBERTY TUNNELS. NOTE THE WINDBREAK AT END OFEAST TUNNEL. burgh, is confined to the east tunnel and southbound traffic to the west tunnel. The South Hills residential district is separated from downtown Pittsburgh by Mount Washington, a steeply rising escarpment south of and adjacent to the Monongahela River. The Mount Washington district immediately south of the Monongahela River has been reached, for many

Jan 1, 1927

By Lawrence Addicks

ONE of the properties of copper, which has done much to give it its present prominent place among the useful metals, is its electrical conductivity, a property which has now become the chief criterion of 'the value of the commerical product. In pursuance of that distinctively American principle that, 1' the best is none too good," metal of the highest conductivity is usually called for even where such extreme purity is of no advantage, for instance, in the making of brass and other alloys. The average brass-founder feels nervous unless his copper is so very pure that it shows a conductivity of 99 or 100 per cent., while the character of the zinc used is usually overlooked in his anxiety. Electrolytic refining has made it possible to produce copper of a' very high degree of purity, the metallic impurities averaging but a few thousandths of 1 per cent.; oxygen, usually present in the form of cuprous oxide, bringing the total up to about a tenth of 1 per cent. The published data bearing upon the relationship between chemical purity and electrical conductivity is, however, very scant,' nearly all the work that has been done having dealt with alloys carrying considerable quantities of the foreign elements. In this paper I have brought together the results of experiments extending over a period of several years that have been carried out with the idea of determining the amount of various elements which would lower the conductivity 3 or 4 per cent.-a series of impure coppers rather than alloys. There are many precautions necessary to keep the conditions

Mar 1, 1905

By M. Yoshinuga, S. Watanabe

Some iron ores, sinters and pellets occasionally show abnormal behavior during reduction which makes them undesirable as blast furnace burden. These may be divided into the following three types: (1) decrepitation of iron ore, (2) swelling of iron ore and pellet, (3) size degradation of sinter. In this paper reduction experiments and microscopic examinations were made to clarify the mechanisms and causes of these abnormal phenomena. Decrepitation occurs mainly when compact hematite ores containing small amounts of limonite are heated to about 500°C. Abnormal swelling of ores and pellets is caused by the rapid growth of fibrous metallic iron from the surface of wustite grains during rapid reduction and is fundamentally related to their original microstructure. Size degradation of sinter occurs through the development of cracks in the reduction stage from hematite to magnetite. About 80% of the iron ore used in Japan's blast furnaces comes from abroad, and the iron and steel industry must import this raw material from distant overseas places at high freight rates. The blast furnace operators, therefore, have made strong efforts to cut costs under these restrictive raw materials conditions by increasing productivity and simultaneously decreasing coke consumption. If, however, a high proportion of the ore burden consists of unsuitable materials furnace irregularities often result, establishing the need for detailed investigations of the basic natures of the ore constituents and their reactions during the reduction process. Recent investigations '-' of various ore burdens suggest that some iron ores, sinters and pellets are occasionally abnormal in appearance and behavior during reduction studies and may prove to be undesirable for use in the blast furnace. In the present study reduction experiments and microscopic observations were made to clarify the causes and the mechanisms of the abnormal behavior observed in some constituents of the burden and their effect on blast furnace performance. REDUCING APPARATUS The four kinds of reducing apparatus used in this investigation were the following: 1. The JIS* (Modified Gakushin') apparatus shown in Fig. la is most commonly used in Japan to evaluate the reducibility of ores under static conditions. It consists of a stainless steel tube of 60 mm inside diam suspended from a balance. 2. Linder's Reduction Test apparatus (Fig. lc) has a reducing barrel 130 mm diam and 200 mm long which rotates at 30 rpm. Some modifications were made in test procedures. 3. Gakushin Standard Test apparatus for determining the reducibility of granular ores (Fig. Id) consists of a horizontal silica tube 32 mm diam, 370 mm long and a movable electric furnace which enables rapid heating and cooling of the specimens. 4. The test apparatus for reduction under load (Fig. lb) gives a comprehensive evaluation of the behavior of ores under conditions simulating the static loading and the chemical reduction conditions encountered in. a blast furnace stack. A stainless steel tube of 50 mm diam and a carbon rod of 35 mm diam were used as the sample container and the support for the weight, respectively. In each investigation care was taken to select the most suitable method and apparatus to distinguish the abnormal nature of the ore in question. SIZE DEGRADATION OF SINTER DURING REDUCTION Sinter makes up the major portion of the blast furnace burden and its behavior during reduction should bear a close relationship to the iron productivity. Recently, some of the sinter was found to show serious size degradation during reduction at a relatively low temperature range. Because this phenomenon was thought to be a possible source of furnace irregularities, tests were made to clarify the phenom-

Jan 1, 1969

By F. D. Wright

Production of a coal preparation plant is governed by many restrictions, such as the tonnage of different products and blends that can be sold within a given period, capacities and output proportions of the cleaning and sizing units, blending proportions, quality specifications, and costs and prices for the various products. Determination of the tonnage of each product and blend that should be made in order to obtain the maximum profit can be difficult unless a systematic method such as linear programming is used. In this paper the basic method of linear programming is described briefly. The Old Ben No. 9 preparation plant is used as an example to illustrate in detail how eqwations can be written to form a linear programming model of a coal preparation plant. Three sample problems, each requiring 56 or more equations and 63 structural variables, were solved with an IBM 650 computer. Linear programming is one of several mathematical tools used for operations research. It has been applied to many fields and has been used by a number of industries either to maximize the profits of certain operations or to minimize costs. P. B. Nalle and L. W. weeks' have described the use of the method by the Riverside Cement Co. to minimize the cost of blending raw materials to make portland cement. Their problem is to obtain at minimum cost a mix with certain specifications from a number of possible materials which have various costs and various amounts of CaO, SiO2, Fe2O3, and other constituents. In a paper on the use of linear programming by the National Coal Board in England, K. B. Williams and K. B. Halley2 describe how the transportation method, a variation of linear programming, is used to minimize the cost of sending 37 grades of coal from 28 mines to seven central washing plants which produce coal for furnace coke and foundry coke. The various coals have different percentages of volatile matter, moisture, sulfur, ash, and phosphorous, so there is considerable choice in how they can be blended to meet the specifications of the two products. The purpose of this paper is to show how linear programming can be used to maximize the profits of a coal washing plant which produces individual final products as well as blends. The Old Ben Corp. furnished assumed sample data from their Old Ben Mine No. 9 preparation plant for this investigation. However, the data that have been used are entirely the author's responsibility. METHOD OF LINEAR PROGRAMMING Numerous articles and books have been written on the theory and applications of linear programming.3-5 However, since the method has not been widely applied by the mining industry, a brief, nontheo-retical discussion of its basic method seems to be in order. Linear programming (Table I) is used to determine the best possible solution to a number of interdependent activities. It is essentially a method for making systematic selections from a number of possible solutions to determine positively the optimum solution. There may be other equally good solutions but no better ones. Each activity must have linear coefficients and there must be a criterion to judge how good the solution actually is. Linear programming is different from the solution

Jan 1, 1961

By Paul J. Bennett, James E. Castle

The sillimanite family of minerals, including kyanite, sillimanite, and andalusite, are anhydrous aluminum silicates with the formula A12O3-SiO2. Dumortierite and topaz are also included in this group because they are closely allied in composition and thermal behavior. However, neither are mined commercially today. They are typical metamorphic minerals which are found in metamorphic rocks on every continent. Sillimanite minerals are prized chiefly for their refractoriness and are important components in a broad range of acid refractory products, especially in mortars and castables. World production of sillimanite minerals is currently about 400,000 tpy and has been increasing at the rate of 3 to 8% a year for many years (Anon., 1972). While these minerals have widespread occurrence, the consumption of sillimanite minerals is concentrated in the relatively few highly industrialized areas where refractories are manufactured, and which in turn are typically close to the major iron and steel producing regions of the world. Thus northern Europe,. England, the United States, and Japan are the principal consumers of refractories and sillimanite minerals. Of these countries only the US is a significant producer. Uses of Kyanite The following specifications are typical for the domestic kyanite industry: Raw Kyanite Concentrates Chemical Analysis 56% AI2O3 min 0.1% CaO max 42% SiO2 0.1% MgO max 1% Acid soluble 0.3% combined Fe2O3 alkali max 1.2% TiO2 max Available Sizes 35, 48, 100, 200, and 325 mesh The largest use for domestic kyanite, both raw and calcined, is in the manufacture of refractory mortars, cements, castables, and plastic ramming mixes. In these applications kyanite constitutes from 10 to 40% of the mixture, the balance being refractory clays and coarser grog materials. A certain proportion of raw kyanite is used to offset the shrinking of the clay binder, whereas the calcined kyanite is used in the coarser sizes for body. Certain high grade refractory shapes and kiln furniture are composed chiefly of graded sizes of calcined kyanite bonded with a little ball clay. In most applications, however, kyanite is used only to fortify the mix or as a minor ingredient. Some manufacturers of mullite brick use domestic calcined kyanite for the fine-grained portion of the brick, but seldom in quantities exceeding 10% by weight. Kyanite is used by ceramic manufacturers of wall tile and sanitary ware to offset shrinkage and cracking after firing. Indian kyanite has traditionally been used to make the coarse grog sizes needed for the manufacture of mullite brick, and for the grog portions of mortar, cement, and castable mixes. It has been largely replaced, however, by synthetic mullite, high fired flint, and diaspore clay or calcined bauxite for other applications. Indian kyanite has been available in lump as well as in granules and concentrates, as are sillimanite materials from India and South Africa. Andalusite is available as 8 mesh granules and as fines with chemical analyses not unlike those of domestic kyanites. From time to time and from place to place minor amounts of other aluminum silicate minerals such as dumortierite, topaz, and pyrophyllite have been made available at various prices and specifications, but have not been significant factors in the refractory industry. A mixture of kyanite and sillimanite of relatively fine grain-size and of low iron content was at one time offered to the molding sand industry by the Du Pont Co. as a byproduct from their deposits of heavy

Jan 1, 1983

By Spencer S. Shannon

The lanthanide elements from lanthanum (atomic number 57) to lutetium (71) plus yttrium (39) are called the rare-earth elements; scandium (21) is chemically similar to yttrium and the lanthanides, but differs in occurrence. The rare-earth metals were divided into three categories by the chemist, Berzelius, in the early 1800s; however, modern usage defines only two groups. The cerium group is named after the most abundant -element and comprises lanthanum (57), cerium (58), praseodymium (59), neodymium (60), promethium (61), samarium (62), europium (63), and gadolinium (64). Traces of natural promethium were discovered in apatite in Finland (Erametsa, 1965). The yttrium group, also named after its most abundant representative, comprises terbium (65), dysprosium (66), holmium (67), erbium (68), thulium (69), ytterbium (70), and lutetium (71). Yttrium most closely resembles holmium in chemical properties, and occurs most commonly with the heavy lanthanides. The rare-earth minerals may be divided into cerium-group, yttrium-group, or mixed-group classes. A number of rare-earth minerals contain thorium and uranium, but these are variable in content and are not essential to the composition of the minerals. In monazite, a mineral that is a principal source of rare earths, the worldwide average content of thorium oxide is 7.2 % ; however, varieties of monazite contain as little as 0.001% and as much as 31.5% thoria. Monazite is the chief ore of thorium and, until recently, thorium has been the main product; the rare-earth metals were in fact byproducts. However, because of the great demand for rare-earth metals by the petroleum refining and the iron and steel industries since the early 1970s, the roles have been reversed so that thorium is now the byproduct. Uses A 9 to 1 mixture of yttrium and thorium oxides is used for high-intensity incandescent lamps and for high-temperature-resistant windows and lenses. Yttrium oxysulfide and orthovanadate, doped with europium oxide, are used in color television tube phosphors. Yttrium, as well as cerium, praseodymium, and samarium, is alloyed with cobalt to form strong permanent magnets. It hardens magnesium alloys and retards the oxidation of iron-chromium alloys. Yttrium-iron garnets are used for transmitting low microwave frequencies. Yttrium-aluminum garnets are used as host crystals for lasers and as artificial gems. Yttria also forms strong, stable, high-temperature refractories. Gadolinium-gallium garnets are used in substrate wafers on which bubble-memory films are deposited. Rare-earth chlorides, particularly of lanthanum, neodymium, and praseodymium, are used as catalysts for petroleum cracking. Mischmetal is used for lighter flints and to improve the ductility and impact strength of iron and steel alloys. Mischmetal also reduces the fatigue resistance of magnesium and aluminum alloys. Rare-earth oxides are used for polishing glasses and lenses. Individual or specific combinations of high-purity oxides are used as additives in glass to maintain or change its color, dispersion, or refractive index. High-purity oxide combinations are also used to color tile and to opacify porcelain enamel. Rare-earth fluorides and oxides are used in carbon-arc electrodes to provide incandescent white light. Lanthanum or gadolinium oxysulfide phosphors, activated with terbium, are used as x-ray screen intensifiers. Hydrogen can be stored by sorption on lanthanum-nickel alloys (Anon., 1979). Thorium232 is bombarded with slow neutrons in breeder reactors to create fissionable thorium233 for nuclear fuel cells. The 330-MW, high-temperature gas-cooled reactor at Fort St.

Jan 1, 1983

By S. R. Goodman, Hsun Hu

A detailed study of texture developmenf in poly crystalline copper atzd 70-30 brass has been completed. Textural changes as a function of deformation are shoum by pole jigmres and by intensity measurements oF- various rejlectiotzs from the rolling plane and the rolling direction. These examinations were accompanied by measurements of stacking fault frequency, hardness changes, and microstructure. Some of the results were briefly presented earlier. Additional results reported here are consistent with the idea that deformation faulting or slip by partial dislocations is of primary importance in the formation of deformation textures in fcc metals. lo examine the idea that deformation faulting is of primary importance in determining whether the texture is the copper type or the brass type an extensive study of the development of polycrystalline textures in copper and 70-30 brass was initiated. Besides the determination of complete pole figures, the intensities of the various reflections from both the rolling plane and the plane perpendicular to the rolling direction, the peak shifts due to deformation stacking faults, and the hardness of the rolled specimens were examined at various reductions from 10 to 99 or 99.5 pct. Mi-crostructures were examined by transmission electron microscopy. Some of the results were briefly presented in an earlier publication.' Since then, additional information has been obtained. This is given in the present paper. EXPERIMENTAL PROCEDURE Material and Specimen Preparation. The material used was a commercial electrolytic copper bar 1i in. wide and 2 in. thick and a 70-30 brass bar la in. wide and 1i in. thick. Chemical analysis indicated a purity of 99.97 pct for the copper, with 0.025 pct 0 as the major impurity. The 70-30 brass was of higher purity with 0.0016 pct 0 as the major impurity. Extreme care was taken in the preparation of the starting material to insure uniformly fine grains with a nearly random initial texture. The two bars were first cold-forged and then annealed to eliminate any original texture. The grains were then refined by several cold rolling (approx 30 pct reduction) and annealing treatments. The + -hr anneals were carried out in a salt bath at 390" to 440°C for copper and at 490°C for brass. The resulting penultimate grain size was 0.06 mm for copper and 0.03 mm for brass, and both showed very little preferred orientation. The number of prior cold rolling and annealing cycles was such that the final thickness after various final reductions of 10 to 95 (for brass) or 99 (for copper) pct was the same (0.020 in.). These annealed strips were rolled in two directions by reversing end for end between passes according to the following schedule: 0.006 in. per pass to 0.100 in., 0.003 in. per pass to 0.050 in., 0.002 in. per pass to 0.025 in., 0.001 in. per pass to 0.020 in. Texture Determination. The development of rolling textures was studied by examining complete pole figures determined from the (111) reflection. Specimens thinned from one face of the strip to half thickness (0.010 in.) were used to obtain the central portion of the pole figures, while specimens thinned from both faces to 0.003 in. were used to obtain the peripheral portion. The reflection and transmission techniques have been described previously. In addition to X-rav pole figures, texture development was also studied b; examining the intensity variation of the (Ill), (200), (2201, (311), (331), (420), and (442) reflections from the rolling plane and from the plane normal to the rolling direction, as a function of deformation. The same specimens used for the central portion of the pole figures were used for the intensity measurements of the various reflections from the rolling plane. For intensity measurements from the plane normal to the rolling direction, composite specimens were prepared by mounting sections cut parallel to the transverse direction of the strip. An epoxy resin was used to bond these sections together, and the entire composite was then mounted in a cold-setting resin to facilitate subsequent polishing and etching to remove distorted metal at the cut. The intensities were expressed in units of the integrated intensities measured from an annealed copper specimen having almost no preferred orientation. Stacking Fault Frequency Determination. Following the analysis of Warren: the stacking fault frequency, a, was determined from the change in the peak separation (A%) of two neighboring reflections of a deformed specimen, as compared with the normal peak separations of a fully annealed specimen. To obtain sufficient intensities for the second-order reflections, (222) and (400), composite specimens were prepared from parallel sections cut from the strip at 30 deg to the rolling direction for copper and 25 deg for the brass.* From texture data, these sections are known to contain a large population of both (111) and (200) planes. Since residual stresses can also cause X-ray line shifts (the direction of line shifts depends upon the sign of the stress), the use of composite specimens consisting of sectioned planes should help compensate for these effects as the residual stresses change sign from the surface to the central section of a rolled strip. Since the amount of peak shift is almost un-measurable in brass rolled 15 pct and in copper rolled

Jan 1, 1969

By Max Y. Seaton

THE scope of this paper will be limited to finished materials that contain a large preponderance (around 80 per cent or more) of magnesium oxide. The large and commercially important production of refractory dolomite and modified dolomites is not discussed here, and the production of magnesium basic carbonate for use as a heat insulator is barely mentioned. The discussion is confined mainly to magnesias produced in comparatively great quantity by direct processing of naturally occurring raw materials and hence excludes secondary or highly purified products such as pharmaceutical products or U.S.P. light and heavy calcined magnesias of commerce. NOMENCLATURE The nomenclature of the magnesia products that will be discussed is somewhat confusing, in that it is customary in the trade to designate as "calcined magnesite" the materials that result from the calcining of magnesite to temperatures that remove the contained carbon dioxide. The finished product, therefore, is not magnesite at all but simply a more or less pure magnesium oxide or magnesia. Furthermore, partly for statistical and partly for commercial reasons, it has been customary, during recent years, to classify as "calcined magnesite" products that result from the heat-treatment of magnesium hydroxide precipitated from magnesium-containing brines; products that, obviously, have no relationship whatever to magnesite. In the listing of magnesia-containing materials, tonnages of which are regularly reported by the Bureau of Mines, reports ordinarily are made under two headings: "caustic calcined" magnesite, in which all of the varieties of products treated at relatively low temperatures are lumped; and "dead-burned" magnesite, in which are included both high-purity and low-purity, and particularly both high-iron and low-iron, materials that have been so heat-treated that the magnesium oxide occurs predominantly as crystalline periclase-materials used almost entirely for refractory purposes. In 1940 the apparent domestic consumption of "caustic calcined" magnesite was approximately 17,000 tons, about 95 per cent of which was produced in this country. The apparent consumption of "dead-burned" magnesite was approximately 172,000 tons, some 82 per cent of which was domestically produced. In both total quantity and percentage of material produced within the United States, these figures are record highs for many years past. UTILIZATION As indicated by these figures, the major tonnage outlet for magnesia is the refractories industry, in which magnesia is employed principally in three ways: (I) as dead-burned grain magnesite for the construction and maintenance of the hearths or bottoms of basic open-hearth furnaces; (2) in the form of refractory magnesite bricks and shapes; and (3) as a chemical

Jan 1, 1942

By C. Feng, W. E. Krul

A study was made of the development of texture and the anisotropy in plastic flow of Ti-8Al-1Mo-1V alloy. Based on Pole figure determinations, the shifting of texture induced by rolling at approximately 400°C was found to be due primarily to slip rotation for the major Portion of the material. Grain boundary shear is believed to be an important factor. The anisotropy of the textured alloy was examined in terms of the variations of yield stress under tension and the ratio of bi -axial strain increments µp, in the temperature range 25" to 290°C. The results were related to Hill&apos;s theory on plastic anisotropy. The Schmid factors of (1100)[1120], (1101)[1120/, and (1101)[1120] slip systems were analyzed and found to be compatible with the observed anisotropy. Cross-slip between these planes was proposed as a possible deformation mode. In a number of published articles, considerable interest has been directed to the possible achievement of texture hardening in hcp metals. Following Backofen, Hosford, and Burke,&apos; this phenomenon was related to the yield criteria of the material and was expressed in terms of the biaxial strain ratio, r = d?w/d?l. The higher the value of r, the greater is the expected potential for texture hardening under certain loading conditions. For a given material, r varies with direction. Such variation can be traced to the anisotropy in plastic flow and can be explained within the framework of the various modes of deformation. Hatch2 found that a high r value coincides with a texture whereby the (0001) pole is closely aligned with the surface normal for sheet materials, Based on the analysis of the slip on the {1010}, {1011}, and (0001) planes, Lee and Backofen3 and Avery, Hosford, and Backofen4 concluded that the resistance to thinning is reduced by the operation of the (0001) <1120> slip system; with this reasoning they were able to explain the low r values (i.e., r « 1) observed in magnesium alloy sheets in the rolling direction and in commercially pure titanium in the transverse direction. The general equation, dealing with plastic flow in a polycrystalline aggregate has been used to correlate the plastic anisotropy and texture. In this expression, T and s are shear and normal stresses, and dri and d? are shear and normal strain increments, respectively. Assuming that five slip systems are operative within each grain and applying the principle of maximum work,5,6 one can determine the m value among the available systems. On this basis, Hosford7 and Chin, Nesbitt, and Williams&apos; were able to correlate m with yield stress under plane-strain compression, and Svensson9 was able to predict the variation of yield stress in textured aluminum. These workers made their analyses from materials in which slip operation is known to be associated with plastic flow. Questions remain regarding the derivation of Hill&apos;s theory on plastic anisotropy,10,11 since it was formulated on von Mises&apos; yield criterion.&apos;&apos; Its ability to deal with other forms of deformation has been in doubt.13 Others have discussed the validity of Hill&apos;s quadratic equation relating strain and yield stress.14&apos;15 For hcp titanium, deformation by various modes of slip and twinning operations has been reported.16-20 If all possible modes of deformation operate and contribute substantially to the plastic flow, it is difficult to imagine how the quadratic expression can suitably describe the anisotropic plastic flow of titanium alloys. Backofen and Hosford15 considered that Hill&apos;s is a macroscopic theory and implied that the major mode of deformation by slip mechanism will adequately describe anisotropy of the material. In the present investigation, slip operation will be shown to play the major role in the development of sheet texture induced by rolling of a commercial titanium alloy. Although twinning and other modes of deformation may also operate, their operation is believed to be secondary. The anisotropic properties of the sheet, which can be expressed in terms of directional variation of r, µp = -d?w/d?l and the yield stress will be shown to be governed primarily by slip operation. MATERIALS AND EXPERIMENTAL TECHNIQUES The titanium alloy chosen for the present investigation had a nominal composition of 8 wt pct Al, 1 wt pct Mo, 1 wt pct V, and 0.1 wt pct interstitial impurities. Sheets varying between 0.1 and 0.15 in. thickness were used. The alloy was received in a condition which was prepared by rolling at 900°C and annealing at 700°C. Subsequently, the sheets were subjected to further reduction in thickness by rolling at 400°C. A total reduction in thickness of 65 to 70 pct was obtained by a series of quick passes in a rolling mill with intermediate reheating. Further reduction in thickness was not possible due to cracking developed at the edges of the sheets. X-ray measurements were conducted in a Siemens and a Norelco unit to determine the texture of the sheets. Reflection techniques were used exclusively with CuK, radiation and a nickel filter. The loss of X-ray intensity due to geometric defocusing was calibrated with a technique described previously." The (0001), (1010), and (1071) pole figures were plotted from 0 to 80 deg, and to present the texture elements quantitatively, inverse pole figures were constructed following the technique described by Jetter, McHargue, and Williams.22 Tensile experiments were carried out at 25", 175",

Jan 1, 1970

By Robert B. Fulton, Gill Montgomery

Fluorspar is the commercial name for fluorite, a mineral that is calcium fluoride, CaF2. The name, derived from the Latin word fluere (to flow), refers to its low melting point and its early use in metallurgy as a flux. It is the principal industrial source of the element fluorine. Cryolite, sodium aluminum fluoride, Na3AlF6, is a rare mineral which has been found in commercial quantities only in Greenland. The natural material has been supplanted by synthetic cryolite for its principal industrial use in the manufacture of aluminum. History Fluorspar was used by the early Greeks and Romans for ornamental purposes as vases, drinking cups, and table tops. Various peoples, including the Chinese and the American Indians, carved ornaments and figurines from large crystals. Its usefulness as a flux was known to Agricola in sixteenth century Europe. Fluorspar mining began in England about 1775 and at various places in the United States between 1820 and 1840. Production grew substantially following the development of basic open-hearth steelmaking, wherein it is used as a flux. Use was stimulated by growth of the steel, aluminum, chemical, and ceramic industries, particularly during World Wars I and II. Fluorocarbons entered the picture in 1931. The use of anhydrous hydrogen fluoride (HF) as a catalyst in the manufacture of alkylate for high octane fuel began in 1942. Differential flotation for separating fluorspar from galena, sphalerite, and common gangue minerals in the 1930s, and the application of heavy-media concentrating methods to the treatment of low-grade ores in the 1940s were outstanding technological advances that facilitated increased production. Recently, pelletizing and briquetting of flotation concentrates for use in steel furnaces and the development of flotation schemes for beneficiating ores containing abundant dolomite and barite have been major improvements in the industry. Uses of Fluorspar Fluorspar is used to make hydrogen fluoride, also called hydrofluoric acid, an intermediate for fluorocarbons, aluminum fluoride, and synthetic cryolite. It is used as a flux in the steel and ceramic industries, in iron foundry and ferroalloy practice, and has many minor specialized uses. Hydrogen fluoride (HF) is produced by reacting acid grade (97% CaF2) fluorspar with sulfuric acid in a heated kiln or retort to produce HF gas and calcium sulfate. After purification by scrubbing, condensing, and distillation, the HF is marketed as anhydrous HF, a colorless fuming liquid, or it may be absorbed in water to form the aqueous acid, usually 70% HF. Synthetic cryolite, organic and inorganic fluoride chemicals, and elemental fluorine are made from hydrofluoric acid. The acid itself is important in catalysis in the manufacture of alkylate, which is an ingredient in high-octane fuel for aircraft and automobiles, in steel pickling, enamel stripping, glass etching and polishing, and in various electroplating operations. The manufacture of one ton of virgin aluminum requires about 50 to 60 lb of fluorine content in synthetic cryolite and alumnium fluoride. This quantity, through improved technology and recovery practices, is being lowered significantly.

Jan 1, 1983

By Max Y. Seaton

The scope of this paper will be limited to finished materials that contain a large preponderance (around 80 per cent or more) of magnesium oxide. The large and commercially important production of refractory dolomite and modified dolomites is not discussed here, and the production of magnesium basic carbonate for use as a heat insulator is barely mentioned. The discussion is confined mainly to magnesias produced in comparatively great quantity by direct processing of naturally occurring raw materials and hence excludes secondary or highly purified products such as pharmaceutical products or U.S.P. light and heavy calcined magnesias of commerce. Nomenclature The nomenclature of the magnesia products that will be discussed is somewhat confusing, in that it is customary in the trade to designate as "calcined magnesite" the materials that result from the calcining of magnesite to temperatures that remove the contained carbon dioxide. The finished product, therefore, is not magnesite at ali but simply a more or less pure magnesium oxide or magnesia. Furthermore, partly for statistical .and partly for commercial reasons, it has been customary, during recent years, to classify as "calcined magnesite" products that result from the heat-treatmerit of magnesium hydroxide precipitated from magnesium-containing brines; prod- ucts that, obviously, have no relationship whatever to magnesite. In the listing of magnesia-containing materials, tonnages of which are regularly reported by the Bureau of Mines, reports ordinarily are made under two headings: "caustic calcined" magnesite, in which all of the varieties of products treated at relatively low temperatures are lumped; and "dead-burned" magnesite, in which are included both high-purity and low-purity, and particularly both high-iron and irow-iron, materials that have been so heat-treated that the magnesium oxide occurs predominantly as crystalline periclase— materials used almost entirely for refractory purposes. In 1940 the apparent domestic consumption of "caustic calcined" magnesite was approximatcly 17,000 tons, "bout 95 Per cent of which was produced in this country. The apparent consumption of "dead-burned" magnesite was approximately 172,000 tons, some 82 per cent of which was domestically produced. In both total quantity and percentage of material produced within the United States, these figures are record highs for manY Years past. Utilization As indicated by these figures, the major tonnage outlet for magnesia is the refractories industry, in which magnesia is employed principally in three ways: (1) as dead-burned grain magnesite for the construction and maintenance of the hearths Or bottomS of basic open-hearth furnaces; (2) in the form of refractory magnesite bricks and shapes; and (3) as a chemical

Jan 1, 1942

By Max Y. Seaton

The scope of this paper will be limited to finished materials that contain a large preponderance (around 80 per cent or more) of magnesium oxide. The large and commercially important production of refractory dolomite and modified dolomites is not discussed here, and the production of magnesium basic carbonate for use as a heat insulator is barely mentioned. The discussion is confined mainly to magnesias produced in comparatively great quantity by direct processing of naturally occurring raw materials and hence excludes secondary or highly purified products such as pharmaceutical products or U.S.P. light and heavy calcined magnesias of commerce. Nomenclature The nomenclature of the magnesia products that will be discussed is somewhat confusing, in that it is customary in the trade to designate as "calcined magnesite" the materials that result from the calcining of magnesite to temperatures that remove the contained carbon dioxide. The finished product, therefore, is not magnesite at ali but simply a more or less pure magnesium oxide or magnesia. Furthermore, partly for statistical .and partly for commercial reasons, it has been customary, during recent years, to classify as "calcined magnesite" products that result from the heat-treatmerit of magnesium hydroxide precipitated from magnesium-containing brines; prod- ucts that, obviously, have no relationship whatever to magnesite. In the listing of magnesia-containing materials, tonnages of which are regularly reported by the Bureau of Mines, reports ordinarily are made under two headings: "caustic calcined" magnesite, in which all of the varieties of products treated at relatively low temperatures are lumped; and "dead-burned" magnesite, in which are included both high-purity and low-purity, and particularly both high-iron and irow-iron, materials that have been so heat-treated that the magnesium oxide occurs predominantly as crystalline periclase— materials used almost entirely for refractory purposes. In 1940 the apparent domestic consumption of "caustic calcined" magnesite was approximatcly 17,000 tons, "bout 95 Per cent of which was produced in this country. The apparent consumption of "dead-burned" magnesite was approximately 172,000 tons, some 82 per cent of which was domestically produced. In both total quantity and percentage of material produced within the United States, these figures are record highs for manY Years past. Utilization As indicated by these figures, the major tonnage outlet for magnesia is the refractories industry, in which magnesia is employed principally in three ways: (1) as dead-burned grain magnesite for the construction and maintenance of the hearths Or bottomS of basic open-hearth furnaces; (2) in the form of refractory magnesite bricks and shapes; and (3) as a chemical

Jan 1, 1942

By A. J. Conelius, D. P. Sobocinski

This paper presents a correlation for predicting the behavior of a water cone as it builds from the static water-oil contact to breakthrough conditions. The correlation is partly empirical and involves dimensionless groups of reservoir and fluid properties and of production and well characteristics. The groups were deduced from the scaling criteria for the immiscible displacement of oil by water. The correlation is based on a limited amount of experimenfal data from a laboratory sand-packed model and on results from a computer program for a two-dimensional, incompressible system. Because the correlating groups are dimensionless, they can be used to estimate the performance of water coning cases not specifically considered in the correlation. However, despite its dimensionless nature, the correlation is not completely general and will not provide meaningful estimates of cone behavior in many situations. INTRODUCTION AND BACKGROUND The production of water from oil wells is a common occurrence which increases the cost of producing operations and may reduce the efficiency of the depletion mechanism and the recovery of reserves. We will deal with one cause of this water production, namely, coning. The coning of water into a producing well is caused by pressure gradients established around the wellbore by the production of fluids from the well. These pressure gradients can raise the water-oil contact near the well where gradients are most severe. Gravity forces that arise from fluid density differences counterbalance the flowing pressure gradients and tend to keep the water out of the oil zone. Therefore, at any given time, there is a balance between gravitational and viscous forces at points on and away from the completion interval. When the dynamic forces at the wellbore exceed gravitational forces, a cone of water will ultimately break into the well to produce water along with the oil. We can expand on this basic visualization of coning by introducing the concepts of stable cone, unstable cone and critical production rate. For instance, if a well is produced at a constant rate and the pressure gradients in the drainage system have become constant, a steady-state condition is reached. If, at this condition, the dynamic forces at the well are less than the gravity forces, then the water or gas cone that has formed will not extend to the well. Moreover, the cone will neither advance nor recede, thus establishing what is known as a stable cone. Conversely, if the pressure in the system is in an unsteady-state condition, then an unstable cone will continue to advance until steady-state conditions prevail. If the flowing pressure drop at the well is suffcient to overcome the gravity forces, the unstable cone will grow and ultimately break into the well. It is important to note that in a realistic sense, stable cones may only be "pseudostable" because the drainage system and pressure distribution generally change. For example, with reservoir depletion, the water-oil contact may advance toward the completion interval, thereby increasing chances for coning. As another example, reduced productivity due to well damage requires a corresponding increase in the flowing pressure drop LO maintain a given production rate. This increase in pressure drop may force an otherwise stable cone into a well. The critical production rate, well known in the literature, is the rate above which the flowing pressure gradient at the well causes water (or gas) to cone into the well. It is, therefore, the maximum rate of oil production without concurrent production of the displacing phase by coning. At the critical rate, a built-up cone is stable but is at a position of incipient breakthrough. Numerous papers have been published on critical rates. Some of the better known of these include the work of (1) Muskat and Wyckoff,&apos; who first dealt with the coning problem; (2) Chaney, et al,&apos; who developed expressions similar to those of Muskat but who presented results in a conven ient-to-use graphical form (the "Sun" method); and (3) Meyer and Garder,b hose analysis is based on radial-flow formulas. One assumption in critical production rate analyses is that the cone has built-up to just before its breakthrough into the well. But, these analyses reveal nothing directly about the time it takes for the cone to build up to this incipient breakthrough position. Thus, water-free oil can be produced from a well for prolonged periods at rates above the critical rate before the well reaches the condition to which the critical rate applies. The published literature contains little on the rate of growth of a cone. Experimentally, Meyer and Searcy studied the rate of rise of a cone in a Hele-Shaw model.&apos; Additional related work on water breakthrough and produced water-oil ratios in water driven reservoirs was reported by Muskat," Hutchinson and Kemp," Henley, et al,&apos; and Stevens, et a1.B Theoretically, the basic coning equations for a water-oil system can be developed by applying the conservation of mass to each of the phases, relating flow velocities with pressure by Darcy&apos;s law, and relating pressures across water-oil interfaces by capillary pressure. With the usual boundaries at the well and reservoir limits, the solution of the resulting equations for the time behavior of a water-oil interface constitutes a free-surface, boundary-value problem. The shape of the boundary depends on the internal potential distribution, while this

Jan 1, 1966

By L. D. Jaffe, D. C. Buffum

EARLIER the authors and coworkers had pre sented data on isothermal temper embrittlement of an SAE 3140 steel?&apos; In that work, however, attention was concentrated on embrittlement at 575°C and below. Preliminary measurements showed that embrittlement at 675 °C was much mote rapid than would be expected from the data at the lower temperatures: and indicated the need for further work above 575°C. The possibility of an upper nose in the time-temperature embrittlement diagram above 575°C was pointed out. Procedure The same heat of SAE 3140 steel was used as in the previous work, and experimental methods were the same. All blanks were austenitized 1 hr at 900°C and water, quenched. Groups were then tempered 1 hr at 675"C, water quenched, and given embrittling treatments for times of 5 min to 240 hr at 675" to 600 °C, as shown in Table I. Other groups, after the temper and quench, were embrittled 48 to 1440 hr at 550°C. Another series was tempered 240 hr at 675"C, quenched, and held for various times at 650" to 375°C (Table 11). For comparison, a series was tempered for these same times at 700°, 675", and 650°C (Table 111). The Ae, temperature for this heat of steel had been determined as approximately 690°C;1*a the treatments at 700°C were introduced to determine the effects of tempering in a range where a little austenite would fonn. A large number of other treatments, involving holding at two temperatures in succession after the temper, and occasionally slow cooling or heating, were also studied. These treatments are listed in the tables. Austenitizing was done in air; all subsequent treatments were in salt. Blanks were always water quenched after the last treatment. The heat-treated blanks were machined to standard V-notch Charpy specimens. A transition curve for each group was obtained by breaking the specimens at various temperatures on a 217 ft-lb impact machine having a striking velocity of 16.8 fps, and plotting the observed percentage of fibrous fracture vs the test temperature. From this plot, the transition temperature was taken as the lowest temperature at which the fracture appeared 100 pct fibrous; its accuracy is estimated as +5"C. Generally, hardness was measured on every bar. Since a decrease in hardness itself seems to decrease the transition temperature somewhat, a correctiona of —0.28"C per Bhn was applied to permit comparison of the transition temperatures on a uniform basis of 24 Rc. The transition temperature and hardness results are given in Tables I through VI. Where overlap of earlier work1.&apos; occurred, data were combined.

Jan 1, 1958

By J. L. Gillson

IN a brief summary of the many occurrences of fluorspar in our western states, it is not possible to go into detail in regard to the geology, mining and milling methods, and reserves about individual deposits. Rather a broad review is made of the occurrences and an analysis of how the western deposits may fit into our future domestic economy is presented. GENERAL STATEMENT ON FLUORSPAR SITUATION Fluorspar has been used for years as a flux in the manufacture of basic open-hearth steel, in foundry cupolas for melting pig iron, in the manufacture of opalescent glass and in the preparation of hydrofluoric acid. In 1880 the annual production of fluorspar in the United States was around 4000 tons per year. By 1900 it was up to 21,656 tons and between 1902 and 1908 it averaged about 40,000 tons annually. Prices were then so low, by present standards, that it seems impossible to believe now that mining could have been performed profitably at the price levels then prevailing. In 1890 fluorspar sold at the mines for $6.70 per ton, in I901 for $5.81, in 1916 for $5.92. When the United States entered World War I, fluorspar production and price skyrocketed; the production reached 263,817 tons in 1918, with prices above $20.00 per ton, and prices were even higher in 1919 and 1920. After 1920, the domestic production fell from the 1918 level to about 125,000 tons annually and the average price dropped back to about $I8.00 per ton. By 1935 the average price had fallen to $15.00, but in 194o with a rising demand the average price of all grades had gone back up to $20.31. Today it is 75 per cent higher than in 1940 and presumably the price of acid grade at least would be even higher if it were not for price ceilings. The first subsequent year that the domestic production exceeded that of 1918 was 1941, and the 1944 production is expected to exceed 400,000 tons, &apos;or over one and a half times that of 1918. In five-year periods, average production and imports were as are shown in Table I. [ ] Many people concerned with the consumption of fluorspar believe that the postwar period ahead will show a repetition of price trends of the last such period. They believe that imports will be- again an important factor in the available supply and the price will fall back gradually toward the prewar level. The following basic factors are pertinent in analyzing this conclusion:

Jan 1, 1945