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By Arnulf Muan, Egil Aukrust

Activities of COO in the three solid solution series COO-MgO, COO-MnO, and COO-"FeO" have been determined at 1200°C by equilibrating oxide samples with a metal phase (cobalt or a Co-Fe alloy) in atmospheres of known oxygen activities. The systems COO-MgO and COO-MnO are ideal, within limits of experimental error, whereas the system COO-"FeO" shows a slight positive deviation from ideality at the temperature of this investigation. KNOWLEDGE of activities of oxide components in solid solutions is necessary for the calculation of the cation distribution among coexisting oxide phases in many important metallurgical, ceramic, and geochemical systems. Very few activity-composition curves are available for such systems at the present time. A start on the prodigious job of obtaining such data has been made by studies of solid solutions with simple sodium chloride type structure containing NiO or "FeO" as a component.1-3 The present paper describes similar studies for solid solutions with sodium chloride type structure containing COO as a component. For the systems COO-MgO and COO-MnO, the activity solid solution is determined by the equation Here po and are the oxygen activities of the gas phase in equilibrium with the phase assemblages metallic cobalt plus oxide solid solution, and metallic cobalt plus pure COO, respectively. In the system CoO-"Fe07', the metal phase is a Co-Fe alloy rather than pure cobalt. In this case the activity of COO in the oxide solid solution is calculated from the equation where a& is the activity of cobalt in the metal phase. Because the system Co-Fe is close to ideal4 and the metal phase appearing in the present work contains less iron than cobalt even at the lowest COO concentrations of the oxide phases used may be set equal to N . Hence, Eq. [2] becomes The value of Nc, can be estimated from the relative stabilities of the oxides COO (see below) and I) EXPERIMENTAL METHOD Two different but closely related procedures were used in the present investigation to determine the activity-composition curves. In one method, the oxide solid solutions were equilibrated against

Jan 1, 1963

Beyer Barometric Condenser The Ingersoll-Rand Co. is now offering to the trade complete steam­condensing plants for all service conditions. This equipment includes the Beyer barometric condenser, for' which the company has secured the patent rights, Imperial duplex and Ingersoll-Rogler straight-line reciprocating dry vacuum pumps and, where required, Cameron simplex and centrifugal pumps. The Beyer barometric condenser is of the counter-current type, in which air and cooling water flow in opposite directions. The steam inlet is at the bottom of the condensing v el, the water inlet above and the air-removal opening at the top. The sheets of cooling water over owing the pool at the inlet point meet the entering steam. The two are brought into intimate contact by conical baffle plates which assist the water to absorb to its full capacity the latent heat of the steam. The non-condensable air liberated in the condensing action rises through the falling water to the removal point at the top, being cooled to practically the temperature of the incoming water. It is also to be noted that ample opportunity is given for the removal of the air content of the water before

Jan 8, 1916

By Jasper L. Stuckey

PYROPHYLLITE, first identified as soapstone,' later as agalmatolite,2 and finally as pyrophyl-lite, has been known to occur in North Carolina for more than 130 years and has been produced intermittently in commercial amounts for the past 100 years. Pyrophyllite mining, however, has become a major industry in North Carolina only during the past 25 years. North Carolina and California are the chief producing states. Current annual production averages 125,000 tons, of which slightly more than 90 pct comes from North Carolina. Distribution and Geologic Setting: All known pyrophyllite deposits in North Carolina are associated with rocks of the Carolina Slate Belt,' which is composed of a vast series of metamorphosed volcanic and sedimentary materials, occurring as two zones extending in a northeast-southwest direction across the state. The larger of these zones, lying in the central Piedmont region, varies from 8 to 50 miles wide. The smaller zone lies along the eastern edge of the Piedmont region and is partly covered by coastal plain sediments. The rocks in both zones consist of a great volcanic-sedimentary series, composed of air-laid and water-laid tuffs and breccias, lava flows, and slates. On the basis of composition, they may be classed into three groups: 1) tuffs, breccias, and lava flows of acid or rhyolitic composition; 2) tuffs, breccias, and lava flows of a basic or andesitic composition; and 3) water-laid slates composed of fine grained materials derived chiefly from the acid tuffs and breccias and

Jan 1, 1959

By J. B. Cheatham, M. D. Biggs

This paper presents a systematic method for determining the forces on a simplified roller bit. The kinematics of an actual roller bit drilling in rock is complex; nevertheless, it is desirable to obtain an accurate analytical model.. As a preliminary study, the roller bit is represented here by a simple two-dimensional bit and the rock by a Coulomb plastic material. Results from previous work, plus additional assumptions, are incorporated into a computer program to determine the forces required to move the bit in a specified manner. Example problems are worked by use of this program. By studying similar drilling problems and by supporting laboratory work, one could eventually obtain an accurate analytical model for drilling by an actual roller bit. This could lead to the compilation of a catalog of results that, in turn, would allow selection of the optimum drill bit for any given situation. INTRODUCTION

Jan 1, 1970

By G. M. Schwartz

THERE has been considerable controversy regarding the structure and mineral constituents produced when iron ore is sintered. This investigation was undertaken in order to establish the fundamental reactions that take place in the sintering process by determining the nature of the resulting minerals. The writer's immediate interest in the subject arose mainly from the request of E. W. Davis for information based on a microscopic study of sinter submitted by him in May, 1926. In the author's preliminary work, samples of iron-ore sinter were secured from the Minnesota School of Mines Experiment Station and from commercial plants. These were polished by the usual methods for polishing opaque ores. In order to study these surfaces satisfactorily, it is necessary to magnify them rather highly, a range from 100 to 1000 dia. being used. For the higher magnifications oil-immersion lenses and an intense source of light are necessary. After the preliminary study had shown the problems involved, a series of small samples were sintered under carefully controlled conditions and with analyzed materials. Variations in the relative amounts of ore, coal and water were made in order to study the effect of each constituent. The attempt has been to arrive at a clearer understanding of the sintering process and the reactions involved without reference to any preconceived notion as to sinter. It is clear that the study of polished surfaces has yielded results not possible with thin sections alone. The thin sections made in this work were found unsatisfactory at magnification greater than 75, whereas magnifications of 1000 were easily studied with reflected light on carefully polished surfaces. A rather complete statement of observed facts is made so that the reader may form his own conclusions. The writer's interpretations are suggested.

Jan 1, 1929

By N. S. Stoloff, J. N. Mushovic

Age hardening response of a Mg-Th-Zr alloy has been studied at temperatures in the range 60° to 450°C. Transmission microscopy revealed clustering of thorium atoms at low aging temperatures, supporting a previous report of GP zone formation. Peak strengthening, which is observed at 325°C, is due to the formation of a coherent, ordered, DO19 type superlattice structure, of Hobable composition Mg3Th, as plates parallel to the matrix prism planes. These plates later reveal a Laves phase structure of composition Mg2Th. The equilibrium Mg4Th phase begins to precipitate in two different forms at an early stage, competitively with the Mg2Th plates. RECENT work on the Mg-Th system indicated that, unlike most magnesium-base alloys, complex precipitation phenomena may be occurring. The partial phase diagram of the Mg-Th system indicates that an equilibrium phase, Mg5Th, is the sole intermediate phase.' sturkey,' however, has reported, using X-ray and electron diffraction techniques, that a metastable fcc Laves phase, Mg2Th, precedes the formation of the equilibrium compound, which he identified as closer in composition to Mg4Th. Murakami et al.3 reported that the equilibrium phase precipitates preferentially on grain boundaries and dislocations in a Mg-1.7 wt pct Th alloy; Kent and Kelly4 aged a more dilute alloy, Mg-0.5 wt pct Th, for 4 days at 220°C and found similar results. In addition, they reported that a platelike phase with a structure close to that of the magnesium matrix forms perpendicular to the basal plane and is probably ordered. Research on a Mg-4 wt pct Th alloy by electrical resistance measurements and transmission electron microscopy has suggested that GP zones may form at low aging temperatures.3 However, the electron micrographs purporting to show this phenomenon were not conclusive. In view of the fragmentary evidence concerning the nature of the precipitation processes in the various Mg-Th alloys, an aging study was undertaken to clarify the characteristics of the various precipitates which form and to correlate the mechanical properties of the system with the direct precipitate-dislocation interactions. The latter results are presented elsewhere.' The purpose of this paper is, therefore, to discuss the precipitation sequence in this system. EXPERIMENTAL PROCEDURE Sheet stock (0.060 and 0.010 in. thick) of a commercial Mg-3.93 wt pct Th-0.42 wt pct Zr alloy (designated HK3lA) similar to that studied by sturkey2 was supplied through the courtesy of Dr. S. L. Couling of Dow Metal Products Co. Zirconium does not enter into any precipitation reactions,' but is present primarily as a grain refiner. The alloy was chill cast, warm rolled to 0.090 in. thick stock, and then finally reduced by a combination of hot and cold rolling. The alloy chemistry is given in Table I. This material was solution treated at 580°C for 4 hr in a dry CO2 atmosphere, and then water quenched. Material in this condition was fairly clear of precipitate particles and was fully recrystallized. Aging at temperatures less than 200°C was accomplished by immersing the alloy in a silicone oil bath; for higher temperatures, aging was done in a salt pot. Age hardening treatments were conducted at 60°, 80°, 105°, 135°, 160°, 250°, 325°, 350°, and 450°C for times ranging from 5 min to 400 hr. Hardness tests were performed on chemically polished 0.060-in.-thick blanks of solution treated material which were aged at the various temperatures for increasing lengths of time. For aging temperatures above 150°C the Rockwell Superficial 30T scale was employed, while samples hardened at temperatures below 150°C were monitored with the 45T scale. Each data point consists of at least three separate readings. Yield stresses also were measured at room temperature on both 0.060 and 0.010 in. sheet specimens aged at 325°C. The aged foils were thinned by the window method in a solution of 80 pct absolute alcohol and 20 pct concentrated perchloric acid (70 pct) maintained at 0°C. A stainless steel cathode was used and the applied voltage was 10 to 15 v. Thinned samples were rinsed in distilled water and pure methanol. After the me-thanol rinse the thin foils were quickly dried between filter paper. Foils prepared by the above method were examined in a Hitachi HU11B electron microscope operating at 100 kv. RESULTS A) Hardness. The hardness data are depicted in Figs. 1 and 2. Peak strengthening occurs at 325°C after aging about 6 min, see Fig. 1. Significant strengthening is achieved also at 350°C, but aging at 450°C produces only softening. The stepped curve at 250°C indicates that a complicated precipitation process may be occurring at that temperature. Fig. 2 suggests that at least two hardening mechanisms exist since the lowest temperature hardness peaks are displaced to the left of the peaks obtained at 135° and 105°C. A great deal of scatter is observed at long times in all cases due to magnesium surface degradation caused by the silicone oil bath. B) Identification of the Strengthening Precipitates. The structure formed atlowagingtemperatures (c10O°C) was not clearly resolvable by transmission microscopy. The only bright-field evidence for a change in structure was a mottled appearance which could be observed at extinction contours, as shown in Fig. 3(a), and the disappearance of this effect when dislocations produced under the influence of the electron beam passed through the matrix, as noted in

Jan 1, 1970

By E. H. Boswell, E. M. Cushing

The Mississippi embayment east of the Mississippi River is part of a vast geologic and hydrologic province. The abundance of water available is largely responsible for the agricultural history of the area and is perhaps the key factor in the rapidly accelerating trend toward industrialization. The multiple artesian aquifer systems that underlie the region and the alluvial aquifer along the Mississippi River are virtually undeveloped sources of fresh water in that they are yielding only a fraction of the water available. The potential yield of the 12 aquifer systems is estimated to be about 25,000 mgd (million gpd) of which only about 600 mgd is presently being withdrawn. The amount of water in storage in these systems is about 1600 trillion gal. Ground water having a dissolved-solids content of less than 500 ppm is generally available at depths of less than 1000 ft, and water having a dissolved-solids content of less than 1000 ppm is available in some places to depths of more than 3000 ft. Iron is the most common troublesome chemical constituent in the ground water. Water in varying amounts is also available from streams within the region. The amount of water which originates within the region and which leaves it as streamflow during a year averages about 50 million acre-ft (about 45,000 mgd). An additional 375 million acre-ft (about 340,000 mgd), which originated outside the region, leaves the region as streamflow during an average year. Some streams have considerable flow during periods of no precipitation and the water during these periods generally has a low dissolved-solids content. Large quantities of water from streams and waterbearing sands (aquifers) are available in the Mississippi embayment east of the Mississippi River. Most of the region is underlain by aquifer systems that will yield large quantities of water to wells, making ground water the most readily available source of fresh water. About 90% of the water used in the region is obtained from wells. Streams have been used primarily to dispose of, and dilute, wastes that have been dumped into them. The Mississippi, Ohio and Tennessee rivers, and the lower parts of the Tombigee and Yazoo rivers also serve as a means of transportation. This nominally water-rich region receives from 48 to 56 in. of precipitation in average years and is crossed by several large rivers. The largest, the Mississippi River, is the western boundary of the region discussed in this paper. The economy of the region is basically agricultural, but industry has become increasingly important since World War 11. The diversification and mechanization of agriculture have resulted in a surplus of manpower, most of which is being absorbed by the expansion of industry. Further industrial expansion probably will occur because of the available manpower, natural resources and economical transportation. Increasing demands on available water supplies will be made and the future economic growth of the region will be largely dependent upon wise utilization and management of the water resources.

Jan 1, 1969

By Maurice L. Pinel, Thomas Wright, Thomas T. Read

The erroneous, but until recently widely prevalent, belief that iron castings were first made in Europe in the fourteenth century has been adequately refuted in a number of earlier papers;1, ll, l² but except for an unpublished metallographic study by the late William Campbell, and a phosphorus analysis by T. A. Wright of the metal of the Han dynasty cast-iron stove described by Laufer,2 nothing was known of either the chemical composition or the metallographic structure of the metal of any ancient iron casting, although data on castings of recent manufacture are abundantly available. The metal of the stove, which had been buried in a grave for at least 15 centuries, was so corroded that it seemed inadvisable to publish the results on it until morc and better specimens from other ancient castings could be obtained. During a journey through China, extending from Peking in the north to Canton in the south and Cheng-tu, Ssu-chuan, in the west, in the late summer and autumn of 1936, one of us (T. T. Read) was fortunate enough to obtain, and bring home for study, nine castings, all more than 1000 years old, of which the date of manufacture is precisely known because of inscriptions cast in them, another that lacks a dated inscription, but of which the date, as explained below, can be otherwise established, and a specimen from the largest iron casting ever made," which is also dated. The period covered by this suite of specimens extends from 502 to 1093 A.D. In addition, a sample was obtained from a casting of date unknown, but which was certainly cast before 1000 A.D. and possibly as early as the third century A.D. A detailed description of these specimens is as follows: I. 502 A.D. A pair [right and left) of recumbent lions (Fig. 1). Base 7¼ by 113/8 in., height over-all 5½in, weight 26 Ib. each. The tranblation of the inscription on the base is: "Made on the twenty-fourth day of the seventh month of the third pear of Ching Ming of Great Wei" (Sept. 11, 502 A.D.).

Jan 1, 1938

By Maurice L. Pinel, Thomas Wright, Thomas T. Read

The erroneous, but until recently widely prevalent, belief that iron castings were first made in Europe in the fourteenth century has been adequately refuted in a number of earlier papers;1, ll, l² but except for an unpublished metallographic study by the late William Campbell, and a phosphorus analysis by T. A. Wright of the metal of the Han dynasty cast-iron stove described by Laufer,2 nothing was known of either the chemical composition or the metallographic structure of the metal of any ancient iron casting, although data on castings of recent manufacture are abundantly available. The metal of the stove, which had been buried in a grave for at least 15 centuries, was so corroded that it seemed inadvisable to publish the results on it until morc and better specimens from other ancient castings could be obtained. During a journey through China, extending from Peking in the north to Canton in the south and Cheng-tu, Ssu-chuan, in the west, in the late summer and autumn of 1936, one of us (T. T. Read) was fortunate enough to obtain, and bring home for study, nine castings, all more than 1000 years old, of which the date of manufacture is precisely known because of inscriptions cast in them, another that lacks a dated inscription, but of which the date, as explained below, can be otherwise established, and a specimen from the largest iron casting ever made," which is also dated. The period covered by this suite of specimens extends from 502 to 1093 A.D. In addition, a sample was obtained from a casting of date unknown, but which was certainly cast before 1000 A.D. and possibly as early as the third century A.D. A detailed description of these specimens is as follows: I. 502 A.D. A pair [right and left) of recumbent lions (Fig. 1). Base 7¼ by 113/8 in., height over-all 5½in, weight 26 Ib. each. The tranblation of the inscription on the base is: "Made on the twenty-fourth day of the seventh month of the third pear of Ching Ming of Great Wei" (Sept. 11, 502 A.D.).

Jan 1, 1938

By G. W. Healy, L. F. Sander

was investigated by reacting thin discs of calcium oxide with gas mixtures of CO2, CO, and Son. Its value was 19,300 * 300 cal independent of temperature in this range. No solid solubility of sulfur in calcium oxide was detected within the limits of the experimental method and it is estimated to be below 0.025 pct by weight. The importance of lime in desulfurization is well-established but complete information on the pure phase equilibrium: CaO + 1/2 s2 = CaS + +02 [11 is not yet available. The goal of this work was to evaluate solid solubility of CaS in CaO and to determine the free-energy change associated with Reaction [I] at temperatures of 1400" to 1650°C. The equilibrium constant for Reaction [1] can be written: It is convenient to rewrite Eq. [2] in the form: where A = {Ps /PqJ1'2 has been referred to' as the "sulfurizing power' of a gas mixture. In this work, thin discs of CaO were suspended in a vertical tube furnace and exposed to CO + CO2 + SOz gas mixtures having known values of A. The samples were then analyzed for sulfur. As expected, X-ray diffraction confirmed that CaS was the only sulfur-bearing phase formed at the relatively low oxygen pressures used. EXPERIMENTAL PROCEDURE Reagent-grade CaCO3 was pressed in a 3/8-in.-diam pill die and prefired in air to produce CaO discs weighing between 0.004 and 0.01 g. Several discs were used to provide a suitable weight for chemical analysis while maintaining a large surface area to react with gas mixtures. These were placed in a platinum mesh basket and suspended in the gas stream in the hot zone of a vertical tube furnace. Desired gas mixtures were prepared from cp grade CO and CO2 and anhydrous grade SO2. The method of soap bubble displacement was used to calibrate capillary flow meters. While this gave excellent results with CO and Con, some problems with bubble insta- bility and soap film "drag" arose with the use of SO2 at low flow rates. Hence, frequent sampling and analysis of gas mixtures was carried out to insure proper control of the ingoing SOZ. The furnace used for gas:solid equilibration was a vertical mullite tube externally wound with 60 pct Pt-40 pct Rh wire having a diameter of 0.028 in. An inner tube of $ in. ID served as the reaction chamber having Pyrex ground joints sealed to the mullite to provide gas-tight connections at top and bottom. A Pt-Pt 10 pct Rh thermocouple was inserted into a protection tube adjacent to the sample basket to measure sample temperature during a run. Constant-temperature control to 2C was observed at any desired set point within the range of this investigation. This was accomplished by a control thermocouple imbedded in the furnace windings which served to actuate an electronic controller wired for high-low operation. The sulfur analyses of the solid samples were carried out using a stoichiometric combustion technique based on the method of Fincham and Richardson. Some analyses were done using a modified evolution method3 but these were used primarily to check the results of the combustion method. The results were in good agreement but the combustion technique of-ferred an advantage in economy of time and material. CALCULATION OF GAS EQUILIBRIA Heating a given mixture of CO + CO + SO2 to high temperatures gives rise to a large number of product species. The details of calculating the partial pressures of these products of interaction and dissociation can be found in several references4,5 and need not be repeated here. The thermodynamic data selected for the major species in the gas mixtures are shown in Table I. Equilibrium constants from these reactions were combined with oxygen, carbon, and sulfur balances and a computer program written to facilitate the calculations. Some early difficulties in reproducing experimental results were finally traced to the effect of atmospheric pressure changes. No reference to consideration of this question had been found in the

Jan 1, 1969

By E. T. Turkdogan

Jan 1, 1962

By R. Costantini

The author discusses the promising future of the use of pipelines for transportation of ore slurries over long distances, citing existing installations. Various criteria and factors affecting the use and size of pipelines are considered. Among the factors influencing the use of pipelines are particle size, specific gravity, abrasiveness, minimum velocities, and pumping considerations. Long-distance transportation of solids by hydraulic pipelines holds the promise of great economic benefits. Today within the confines of most mineral processing plants, the moving of solids about in slurry form by pipeline is commonplace, since the method offers great advantages when conditions are suitable. Yet, this method is surprisingly slow in being adopted on a broad scale for transportation of solids over long distances (arbitrarily the term will be applied to one over five miles long). This is especially surprising in view of the successful realization in this country within the last five years of two daring ventures in long-distance solids pipelines. A 72-mile long, 6-in. diam pipeline of the American Gilsonite Co. has been satisfactorily transporting 700 tpd of gilsonite from the mine at Bonanza, Utah, to the processing plant at Grand Junction, Colo., since April 1957. The 108-mile long 10-in. diam pipeline of the Pittsburgh Consolidation Coal Co. has been transporting about 4000 tpd of finely crushed coal from the mine at Cadiz, Ohio, to the Eastlake power plant of the Cleveland Electric Illuminating Co. on Lake Erie since January 1958. However, besides two projects in the operations of The Anaconda Co. there have been hardly any other significant solids pipeline developments in the minerals industry during the last three years. The two projects are the 14-mile long, 6-in. diam copper concentrate gravity pipeline at Anaconda's El Salvador project in Chile which has been transporting about 800 tpd since January 1959. The second is a 16-in. diam tailings pipeline at the Anaconda Reduction Works, Anaconda, Mont., designed to transport about 20,000 tpd of deslimed flotation tailings for dam building. This pipeline, which is currently undergoing tryout tests and which will be about seven miles in length, will have a maximum of three 20-in. rubber-lined centrifugal pumps in series at the starting point, each developing a maximum of 100 ft of head, to supplement gravity. It is the writer's opinion that the major reason for the hesitation in considering pipeline operations is confusion due to an inadequate understanding of the basic physical principles affecting the slurry flow process by many engineers in the industry. This in turn begets an attitude of fear and trepidation instead of confidence on the part of many management executives, which leads to a minimizing of the advantages and exaggeration of difficulties when considering the possibility of a long-distance solids pipeline. The promotion of better understanding and consequently the promotion of greater confidence in the potentials of long-distance solids pipelines when conditions are suitable is thus the main purpose of this article. To this end, after considering several examples of the possibilities for solids pipelines in the minerals field, the relative significance of the major factors affecting pulp flow, and some major aspects of slurry pumping will be discussed on a general qualitative level. Then a brief outline of the semi-empirical quantitative methods developed to date for estimating slurry flow behavior will be presented. SOME POSSIBILITIES To give an idea of the magnitude of the possible economic benefits, it should be interesting to mention briefly some of the projects currently under consideration and to suggest some likely future possibilities. At Anaconda's El Salvador Project in Chile (Fig. 1) it is eventually planned to extend the existing 14-mile pipeline by another 60 miles to bring the copper concentrates down to the coast of the Pacific Ocean. Preliminary tests indicate that the projected 6-in. pipeline will be able to transport approximately 2000 tpd of concentrates at a pulp density of 40 to

Jan 1, 1961

By R. D. Pehlke, J. V. Gluck

The limiting activity coefficient of zinc in a "binary " solvent has been described for several dilute ternary solutions by combining literature data from recent interaction studies in the terminal regions with thermodynamic data for the central regions. Results are discussed in terms of the Alcock and Richardson random solution model. The observed behavior agrees semiquantitatively with predictions using the model. RECENT efforts in the thermodynamics of dilute ternary liquid metallic solutions have been mainly concerned with the interactions between two dilute solutes, that is, the terminal region at an apex of the composition diagram.'-' A more general case is that of the behavior of a dilute solute over the full range of a ternary system, or, more specifically, the limiting activity of solute i as projected to the k-j binary side of the i-j-k composition triangle. An implication of this is that the interaction between i and j at the k apex should connect in some way to the interaction between i and k at the j apex. A model to characterize various types of expected behavior has been discussed by Alcock and Richardson.9,10 Such behavior can range from a simple linear relation for In yi over the 1-k binary to more complex curved relations which depend on various assumptions regarding the heat of solution in the j-k binary system and the presence or absence of clustering with solute i. Quantitative data to assess these concepts have been limited primarily to the cases of nonmetallic interstitial solutes in ferrous solutions. Alcock, Richardson, and various coworkers9-13 have discussed the behavior of oxygen, sulfur, silicon, or hydrogen in dilute solution over the range of iron + metal systems; however, the only data considered by them for substitutional nonferrous metallic solutions were the results of Elliott and Chipman concerning the activity of cadmium in the Pb + Sn, Pb + Bi, and Pb + Sb systems.9 These data were limited and did not cover the terminal regions in detail. An opportunity to extend the Alcock and Richardson considerations to the dilute solution of zinc in various "binary" solvents has been afforded by combining results of several of the recent investigations of ter-minal-region interactions with previous data from the literature for the same more concentrated solutions. RESULTS AND DISCUSSION The results of the analysis are shown in Figs. 1 to 5 where the log activity coefficient, (In yZn)xzn--o, is plotted vs the composition of the "binary" solvent. In these plots the end points are the values for In yzn in the appropriate binary solution with Bi, Pb, Sn, Cd, or In at the indicated temperature—usually 550°C (823°K). For the terminal regions the slopes were drawn using the first-order interaction parameters taken from various studies reported in the literature. The data points shown in the central regions were obtained by the short extrapolation to infinite dilution of the logarithm of the activity coefficient calculated from thermodynamic studies reported in the literature for the same systems. The sources of the data are indicated on each figure. Second-order effects were not considered. Reasonably smooth curves can be drawn to connect the central region with the terminal regions for the Zn-Pb + Bi system, Fig. 1, the Zn-Pb + Zn system, Fig. 1, and the Zn-Bi + Cd and Zn-Bi + Sn systems, Fig. 2. As shown in Fig. 2, where central region data are available from two independent investigations, the agreement is quite good. The Zn-Pb + Cd system does not appear to be as well behaved as the previous four, Fig. 3; however, this type of behavior has also been

Jan 1, 1970

By Nicholas J. Grant, Olaf Troili, John Chipman

IN recent studies of the factors which affect the rate of desulphurization and its equilibrium, it became apparent that certain concurrent reactions were operative which had a significant effect on desulphurization. This is emphasized in the experiments of Hatch and Chipman1 and of Grant, Kalling, and Chipman' by the slow approach to a final state of equilibrium which is in marked contrast to the initial rapid transfer of sulphur from metal to slag. Since the removal of sulphur is of such profound importance in iron and steelmaking, it appeared necessary to investigate the reactions responsible for this behavior. It is now known that the presence of iron oxide in the slag interferes seriously with the principal reaction of blast-furnace desulphurization: CaO (slag) +-S + C - CaS (slag) + CO [l] The interfering reaction is most simply expressed as: CaS (slag) + 0 = CaO (slag) +-S 121 and a small concentration of oxygen (or FeO) is sufficient to hold a considerable amount of sulphur in the metal. It has been shown by Grant, Kalling, and Chipman2 that the addition of MnO to blast-furnace slag slows the removal of sulphur from the metal. This effect overshadows the contribution of MnO to basicity and is ascribed to its oxidizing power. It will be shown in this paper that SiO, also has sufficient oxidizing power to interfere with blastfurnace desulphurization. This is, of course, only one of its several effects. Primarily it is an acid and therefore reduces the concentration of excess lime. But when silicon is reduced to the metal the oxygen to which it was previously bonded becomes in part available for reaction 2. The proof of this statement is found in the following experiments. Experimental Procedure and Results Utilizing the same procedure and apparatus described by Grant, Kalling, and Chipman' five additional heats were made using slags IV and 11, the starting compositions of which were: slag IV—40 CaO, 10 MgO, 35 SiO,, 15 A1,0,; and slag 11—50 CaO, 10 MgO, 25 SiO,, 15 Al3O3. An important difference between these heats and those previously reported was that silicon to the extent of 1 to 4 pct was added to the present heats whereas the starting silicon content was formerly about 0.2 pct. Table I shows the slag and metal analyses for heats 82 to 87, and Table I1 shows the silicon addi- tions made to the charge. These additions are based on 400 g of metal and 400 g of slag. All heats had 1.65 400pct S charged before the cold slagadditions. The temperature was maintained at 1525°C. Rate of SiO, Reduction: Fig. 1 shows the silicon content of the metal in contact with slag IV at 1525°C as a function of time. Heat 70 from the work of Grant, afunctionKalling,of and Chipman is included as the lowest starting silicon. It will be noted that eeven with 4 pct Si in the starting metal, there is an increase in silicon content with time. Heat 84 is apparently approaching silicon equilibrium very slowly. Heats 70 and 82 with very much lower slowly.starting silicon show a more rapid initial rise in startingsilicon content but do not reach equilibrium during a long holding period. Fig. 2 shows 3 different initial silicon contents for Fig.2shows3differentheats 73 (from Grant, Kalling, and Chipman) 86 and 87, in contact with slag II, the most basic slag. Heat 73 is increasing in silicon with time, whereas heat 87 with an initial silicon content of 3.7 pct shows a decrease with time. Heat 86 shows a very close approach to equilibrium. The rate of transfer of silicon from slag to equilibrium.metal is very slow in all of those heats, even those which are initially far from equilibrium. ____

Jan 1, 1952

By U. W. Lisner, V. J. Hucka

Coal, which was discovered in Utah in 1849, covers about 18% of the total area. Production in 1981 was more than 13 Mt (14 million st). However, some Utah coal mines are quite gassy. If longwall face technology is applied, then release of a large volume of methane may be expected during the mining process. Investigations on methane content have been made by use of an isothermic bubble desorbometer. A desorbable methane content of 0.5 to 16 m3/t (20 to 632 cu ft per st) of coal has been determined.

Jan 1, 1985

By K. P. Fournier

This report describes work on the problem of predicting oil recovery from a reservoir into which water is injected at a temperature higher than the reservoir temperature, taking into account effects of vis cosity-ratio reduction, heat loss and thermal expansion. It includes the derivation of the equations involved, the finite difference equations used to solve the partial differential equation which models the system, and the results obtained using the IBM 1620 and 7090-1401 computers. Figures and tables show present results of this study of recovery as a function of reservoir thickness and injection rate. For a possible reservoir hot water flood in which 1,000 BWPD at 250F are injected, an additional 5 per cent recovery of oil in place in a swept 1,000-ft-radius reservoir is predicted after injection of one pore volume of water. INTRODUCTION The problem of predicting oil recovery from the injection of hot water has been discussed by several researchers. l-6,19 In no case has the problem of predicting heat losses been rigorously incorporated into the recovery and displacement calculation problem. Willman et al. describe an approximate method of such treatment. 1 The calculation of heat losses in a reservoir and the corresponding temperature distribution while injecting a hot fluid has been attempted by several authors.7'8 In this report a method is presented to numerically predict the oil displacement by hot water in a radial system, taking into account the heat losses to adjacent strata, changes in viscosity ratio with temperature and the thermal-expansion effect for both oil and water. DERIVATION OF BASIC EQUATIONS We start with the familiar Buckley-Leverettg equation for a radial system:* This is sometimes referred to as the Lagrangian form of the displacement equation. If the injection water is at some temperature Ti which is above reservoir temperature TR, then lw, the flowing fraction which is water, is a function of both water saturation and fluid temperature at any given time and position in the reservoir. The temperature dependence of lw results from the temperature dependence of the viscosity ratio µo/µm of which lw is a function. Thus:

Jan 1, 1966

By J. C. Osmond

One of the least known geologic regions in the U.S. is the area now called the Basin and Range Province. It is paradoxical that so little geologic information has been compiled for a province that has yielded billions of dollars worth of metals and is currently producing a small amount of oil. Regional stratigraphic studies of parts of this large territory have been published only recently, and regional structural interpretations of even parts of the province are rare in the literature. This, of course, does great injustice to the earliest workers: Gilbert,1,2 Russell,9 Le Conte,4 Spurr,5 Louderback,8 and others, who recognized the area as distinctively different from the rest of North America. Their simplified picture of the structure of the ranges and the province as a whole is the groundwork for present understanding and has never been superseded. Since their early works, however, geologic data from the province has consisted largely of detailed reports of widely scattered mining districts. Each district has been described as though it were an island in an unknown sea. More recent syntheses of the geologic history have been prepared by Lindgren,7 Ransome,8 Nolan,9 Bill-ingsley and Locke,30 Longwell,11 and Eardley.12 The tentative nature of the present interpretation, which treats the structural evolution of the Utah and Nevada area, must be considered in light of the scarcity of geologic information from the province as a whole. The methods of interpreting tectonic history from stratigraphy are based largely on the concepts of Marshal Kay.23 Discussions with Hoover Mackin also have aided in organizing the Tertiary history. TECTONIC AND STRATIGRAPHIC SETTING Two approaches to the subject of the tectonic history are possible; they correspond to looking through opposite ends of a pair of binoculars. One involves an expansion and extension of detailed work and the other an interpretation based on regional geological relationships. It is believed that the second approach, used here, is not in disagreement with detailed observations. The area of the Basin and Range Province is shown in Fig. 1. Within this area middle Tertiary to Recent high-angle faulting has controlled development of mountain ranges and valleys. Only the part of the area north of Las Vegas, Nev., and south of the Snake River in Idaho will be considered in this article. Within this part of the province most of the ranges trend north-south. Approximately two thirds of the area is covered by late Tertiary to Recent valley fill and lake deposits.

Jan 1, 1961

By Thomas C. Wilder

Jan 1, 1965

By R. K. Agarwal

In this paper, a new technique developed to analyze two-dimensional nonhomogeneous models is described. A simple three-layered medium with a circular hole centrally located in the intermediate layer is considered. The layered sheet is loaded uniaxially perpendicular to the stratification. The Young's modulus of the intermediate layer is lower than that of the outer layers. The stress distribution around the circular hole in a stratified medium is significantly different when compared to the case of a continuous homogeneous medium. The distribution depends upon the ratio of the height of the intermediate layer and the hole diameter. A comparison of stress distribution and procedures for preparation and testing of the model are given. The potential of the technique is outlined. In the process of applying the techniques of stress analysis to problems of rock mechanics, the recent discernible trend has been to postulate highly idealized models of physical situations. As new techniques have been developed, more complicated models have been conceived to simulate mote accurately the physical environment to which the analysis results are eventually applied. In this investigation, a new technique is developed to analyze two-dimensional nonhomogeneous models. The technique is used to determine the stress concentration around a circular hole in a soft material overlain and underlain by a hard material. In mining practice, such situations arise commonly in coal deposits and frequently in bedded or vein-type metallic mineral deposits. DEFINITION OF THE PROBLEM A plate, consisting of three layers with a circular hole in the intermediate layer, is loaded uniaxially, Fig. 1. The variable in the experimental investigation is the height of the intermediate layer, H. The diameter of the hole, D, is kept constant. The stress concentration factors around the periphery of the hole, for various values of H/D, are evaluated using the technique of photoelasticity, Table I. TECHNIQUE OF EXPLORATION Photoelastic analyses of composite models have hitherto been limited to the study of lap and butt joints between glued metals and dissimilar materials.1-3 In mining, Haber and Oudenhoven used composite models to study the stress distribution around a circular hole in two-layered media and the behavior of elastic liners in shallow underground openings.4-5 They used the stress freezing technique devised by Dally et a1.6 The procedure used in this investigation is outlined below: Casting of Layer A: Flat sheets of plastic were cast in a silicon-coated mold using Araldite 502 with hardener 951 in the ratio of 100:8 by weight. After

Jan 1, 1969

By D. L. Katz, M. J. Rzasa

The derivations of three methods of computing the static pressure gradients in natural gas wells have been presented to show the assumptions made. Charts were developed from which the pressure gradients may be read when the well-head pressure, the well fluid gravity, depth, and the average well temperature are given. A chart for estimating the well fluid gravity from the condensate content and separator gas gravity is included. The effect of the increased average well temperature after flow on the calculation of the static pressure gradient is discussed. Introduction Reservoir pressures have been calculated from well-head pressures for gas wells for many years. As the pressure measurements become more accurate, the need for a reliable calculation of the static pressure gradient often arises. This paper will develop the several methods for computing the pressure gradient in gas wells and make a comparison between them. The method of calculating static pressure gradients in common use is Eq. I (ref. I) or its counterpart which includes a factor for the deviation of the gas from the ideal gas law. P2 - P1 = P1(e0.0000347GX _ I) Eq. [I] in which P1 = pressure at well head, lb. per sq. in. abs. PP = pressure at bottom of well, Ib. per sq. in. abs. G = gas gravity X = depth of well, ft. An alternate method is to compute the average density of the gas in the well and multiply by the well depth in a manner similar to that used for liquid gradients. Derivation of Formulas A static pressure gradient is a special case of the general fluid-flow equation. Consider a pound of fluid flowing in a vertical column from point I to point 2, Fig. I. By an energy balance for fluid flowing from I to 2: U1 + P1V1 + u12/2g + X1 + q = U2 + P2V2+ u22/2g+X2 +W [2] in which U = internal energy, ft-lb. per lb. P = pressure, lb. per sq. ft. V = volume, cu. ft. per lb. u = average linear velocity, ft. per sec. X = height above datum, fl. q = heat absorbed by fluid, ft-Ib. pcr lb. W = work done by system, ft-lb. per lb. An energy balance on the fluid itself gives: U = ?TdS - ?PdV + etc. [3] in which T = temperature, deg- R- S = entropy, ft-lb. per deg. R. per lb.

Jan 1, 1945