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By A. K. Csazar, L. W. Holm

This paper describes our investigation of a post-water-flood, oil recovery process which consists of injecting a slug of propane followed by water. Also described are the results obtained by applying a modification of the process in which gas was injected ahead of the water. Under the conditions of the latter experiments, misci-bility was not achieved between the propane and gas. Preliminary experiments or) uniform, watered-out sandstone cores showed that an oil bank could be formed and produced by applying this recovery process. However, since reservoirs are not uniform in structure, the process also was applied to porous media containing irregular porosity and to stratified sand systems. As a supplenzerrt to the experinlental work, a mathernatical procedure was developed for calculating the performance of the recovery process in a bounded, layered, porous system with crossflow between layers. As a specific example, the method was applied to predict the perforrnance of the recovery process in a 6-ft long, two-layer, stratified, unconsolidated sand model for comparison with experinlental data. The calculations were programed for the ZBM 704 computer. The equations and calcula-tional procedure presented can be extended to systems containing any number of randomly distributed permeability variations or any number of parallel layers. INTRODUCTION The problem of recovering the oil that remains in a reservoir which has been waterflooded is receiving considerable attention now as an increasing number of water floods reach an economic limit. A large number of the waterflood projects are in shallow reservoirs which are at pressures below 1,000 psi. It has been demonstrated in the laboratory that post-waterflood oil can be recover-ered by miscible displacement, but the LPG-gas, miscible flood and the enriched gas drive cannot be applied effectively at pressures below 1,000 psi. Only a few reports have appeared in the literature2-4 on low pressure, partially miscible recovery methods. However, it is possible to use LPG in a partially miscible displacement process in a reservoir where pressures of 200 to 1,000 psi can be achieved. Under these Pressures and at normal reservoir temperatures, propane is miscible with the oil; but, of course, gas or water used to drive the propane slug would not be miscible with the propane. Because of the lack of complete miscibility, it has generally been concluded that excessive amounts of propane would be required to recover oil and that such a recovery method would not be economical; however, we have found that under conditions present in certain reservoirs, an imrniscible recovery process can be applied effectively. The oil saturation in reservoirs at the economic limit of waterflood projects is usually in the range of 20 to 35 per cent of the pore space." A certain portion of this oil is left trapped by water in various size pores of the rock, but a good part of this so-called "residual" oil can be present in the less permeable lenses or layers of the reservoir rock which were by-passed to some degree by the water. The oil in these permeability traps can be produced only if favorable pressure gradients are formed in the reservoirs between adjacent zones of high and low permeabilities. A low viscosity liquid, miscible with the oil in place, which is driven by water through a stratified or heterogeneous porous system can aid in the development of these favorable pressure gradients. The oil that is released thereby from the permeability traps can be recovered by the subsequent water flood. Studies were made to determine how much oil could be recovered from homogeneous and stratified cores and models, which had been water flooded, by injecting a slug of propane and driving it with water. The effect of injecting a slug of gas ahead of the water was also determined. Most of the work described herein was done with the propane-water combination; unless otherwise specified, no gas was injected. The principal objectives of the investigation were to determine (1) if an oil bank could be formed and (2) what ratio of oil recovered to propane injected would be obtained. A further objective was to develop a method for calculating fluid-flow performance in stratified systems which would account for fluid transfer between zones in hydrodynamic communication but of different permeabilities. THEORETICAL ANALYSIS In a theoretical study of the recovery process, analytical expressions were derived to calculate the pressure distribution, the fluid flux in longitudinal (parallel to layers) and transversal (across the layers) directions, and the fluid distribution at any point in the system. The equations were developed for a two-layer porous system in which it was assumed that the fluids in the system were incompressible and that capillary and gravity effects were

By A. U. Seybolt, C. H. Mathewson

As is well known, many questions affecting the properties and uses of a metal cannot be answered without careful consideration of the state of purity realized in the various operations of preparation, refining, or special treatment that have brought the product to its final state. The occurrence of an impurity in minute quantity offers no guarantee that its effect will be inconsiderable because dissolved substances often modify the properties of a metal quite out of proportion to their concentration. In such cases the determination of solid solubility must be accepted as a problem of considerable difficulty, requiring the use of especially purified materials and methods not ordinarily used in the metallurgical laboratory. This aspect of the equilibrium between metals and their oxides is especially important and a search for fundamental data reveals little except conflicting opinion even concerning the systems of common occurrence and interest. Rhines and Mathewson1 in 1934 studied the solubility of oxygen in solid copper by annealing to equilibrium in air and gave reasons for the failure of other methods, notably the ordinary procedure of heat-treatment followed by microscopic examination, to yield reliable results. In this paper, a similar study has been made of the solubility of oxygen in cobalt. The simple theory of this method is outlined below.

Jan 1, 1935

By E. V. Potter

For a nurnber of years, it has been known that manganese made by electro-deposition under certain conditions is ductile while under other conditions it is very brittle. The ductile metal is gamma manganese normally stable only between 1100 and 1138°C1; the brittle metal is alpha manganese, stable up to 727OC. The ductile metal is not stable, but gradually changes to the brittle form; the time required to complete the transfornlation is about 20 days at room temperature. Other observations have indicated that the transformation is completed in 10 to 15 min. at about 125°C, while at — 10°C, no appreciable change occurs in 9 months. The properties of gainma and alpha Illanganese in the pure state are ordinarilj difficult to determine because the gamma structure cannot be retained by normal quenching procedures and alpha manganese is so brittle, it is difficult to obtain specimens free from flaws. In a recent investigation2 some properties of gamma and alpha manganese were determined by studying the ductile electrolytic metal and determining the changes in its properties as it transformed to the brittle alpha form. These investigations provided an excellent opportunity for following the progress of the transition and studying its mechanism. The results of a series of such investigations are reported in this paper. Procedure Various properties of manganese were determined starting with the metal in the original ductile gamma form and following the subsequent changes in its properties as the metal transformed to the brittle alpha form. These observations were made at various temperatures, the data providing information regartling the mechanism of the transformation as well as the effect of temperature 011 the transition rate. Structure and resistivity values gave the most significant results, so this paper is concerned primarily with them. The structure was studied microscopically as well as by X ray diffraction. The resistivity was determined on strips of the metal by measuring the potential drop across a given length of the specimen. Current was passed through the specimen by wires soldered to its ends, and the potential connections were made by wires looped around the specimen near its center. The current was determined by the potential drop across a standard resistor connected in series with the specimen, the potential drop being measured on a potentiometer. In the temperature range from room temperature to 100°C an ordinary drying oven was used to heat the specimen. This was entirely satisfactory except at 100°C, where the time required to heat the specimen was long compared to the transition time, making the initial section of the resistivity curve unsatisfactory. To overcome this limitation, at 100°C and higher a thermostatically controlled oil bath was used to heat the specimens. The block on which the specimen was mountetl was plunged into the hot oil at the start of each test. The heating time was thereby reduced from 5 min. to about 6 sec, and dependable resistivity values could be obtained through 160°C. At this point the whole transition, including the warm-up time for the specimen, required only about 20 sec and it was not considered worth while trying to extend the temperature range further. Aside from the heating problem, the problem of making a sufficient number of accurate resistivity determinations became more and more difficult as the temperature was raised. Using the manually operated potentiometer, 100°C was about as far as it was possible to go. At this temperature and above, a self-balancing photoelectric recording potentiometer was used. Its response was quite rapid, and it proved to be entirely satisfactory all the way through 160°C, where the tests were stopped because of the specimen heating problem rather than any limitation of the potentiometer recorder. The metal used in these tests was prepared at the Salt Lake City laboratory of the Bureau of Mines. The method of preparation is discussed in a paper by Schlain and Prater.3 The sheets were about 2 3/8 by 5 3/16 in. and varied from 10 to 16 mils in thickness. They could be cut readily into pieces suitable for the various tests. X ray and microstructure determinations were made on pieces about 1/8 to 1/4 in. wide and about 1 in. long, while resistivity measurements were made on strips as long as possible and about 55 in. wide. The thickness of each sheet was not uniform over all its surface. This had no bearing on the X ray and microstructure determinations, but sections as nearly uniform and free from flaws as possible were chosen for the resistivity determinations. The gamma manganese was electro-deposited at 30°C, the time of deposition ranging from 5 to 12 hr for each sheet. Whenever possible, the tests were started directly after the metal was stripped from the cathode; otherwise the sheet was placed immediately

Jan 1, 1950

By A. C. Dorenfeld

Ores of the Mammoth mining district, some 45 miles northeast of Tucson, Arizona, are treated by Mammoth-St. Anthony, Ltd. The ores now treated come from a complex system of veins and faults, comprising three mines, in close proximity: The Mohawk, Mammoth and Collins. The ore treated in the past was oxide ore, which contains economic amounts of gold, silver, lead, molybdenum, and vanadium (as wulfenite and vanadanite). The lead-zinc sulphide ore has never been treated before. The Ore The sulphide ore contains galena, sphalerite, marmatite, pyrite and some chal-copyrite, covellite, chalcocite and bornite, as well as small amounts of gold and silver. The value of the ore is principally in the lead and zinc content. The lead-zinc sulphides are substantially liberated at a minus 65-mesh grind. However, a large part of the chalcopyrite and other copper minerals is not freed, but remains as pin points on the sphalerite. Economically, the copper is unimportant. The gangue is a rhyolite granite, with very little limestone. There is no molybdenum or vanadikm in the sulphide ore. History of Sulphide Treatment Test work on samples of the sulphide ore was conducted by several equipment companies, the Arizona Bureau of Mines and the company's laboratory. Results of this test work indicated that for some reason, which at the time could not be explained, recoveries would be only about 65 per cent lead and 50 per cent zinc. Notwithstanding this, because of the nation's need for metals, the management built a 150-ton treatment plant. The mill was started in June 1942. During December 1942, using the standard method of treating lead-zinc ore, the monthly results were as shown in Table I. These results were poor. Too much lead was in the zinc concentrate, and too much zinc in the lead concentrate. It should be noted here. that prior to December attempts were made to depress the sphalerite with large and varied amounts of cyanide, zinc sulphate, and sodium sulphite with poor results.

Jan 1, 1947

By A. C. Dorenfeld

Ores of the Mammoth mining district, some 45 miles northeast of Tucson, Arizona, are treated by Mammoth-St. Anthony, Ltd. The ores now treated come from a complex system of veins and faults, comprising three mines, in close proximity: The Mohawk, Mammoth and Collins. The ore treated in the past was oxide ore, which contains economic amounts of gold, silver, lead, molybdenum, and vanadium (as wulfenite and vanadanite). The lead-zinc sulphide ore has never been treated before. The Ore The sulphide ore contains galena, sphalerite, marmatite, pyrite and some chal-copyrite, covellite, chalcocite and bornite, as well as small amounts of gold and silver. The value of the ore is principally in the lead and zinc content. The lead-zinc sulphides are substantially liberated at a minus 65-mesh grind. However, a large part of the chalcopyrite and other copper minerals is not freed, but remains as pin points on the sphalerite. Economically, the copper is unimportant. The gangue is a rhyolite granite, with very little limestone. There is no molybdenum or vanadikm in the sulphide ore. History of Sulphide Treatment Test work on samples of the sulphide ore was conducted by several equipment companies, the Arizona Bureau of Mines and the company's laboratory. Results of this test work indicated that for some reason, which at the time could not be explained, recoveries would be only about 65 per cent lead and 50 per cent zinc. Notwithstanding this, because of the nation's need for metals, the management built a 150-ton treatment plant. The mill was started in June 1942. During December 1942, using the standard method of treating lead-zinc ore, the monthly results were as shown in Table I. These results were poor. Too much lead was in the zinc concentrate, and too much zinc in the lead concentrate. It should be noted here. that prior to December attempts were made to depress the sphalerite with large and varied amounts of cyanide, zinc sulphate, and sodium sulphite with poor results.

Jan 1, 1947

Reply to discussion of the paper of C. W. Washburne, presented at the New York meeting, February, 1914 (Trans., xlviii, 687 to 694 (1914)). C. W. WASHBURNE, New York, N. Y. (communication to the Secretary*).-Professor Lane makes an interesting contribution to the study. of chloride waters, in saying that calcium chloride waters occur not only in the greenstones of the Lake Superior copper mines, but also in the interbedded -felsitic conglomerates and "in far-removed sandstones, e.g., near Whitefish lake, and Ontonagon, in the Michigan iron mines, and in the Storm King granite." Surely these are not connate waters preserved from the Algonkian sea, assuming that the Algonkian sediments are marine rather than continental. Finding the same type of water in the Storm King granite points rather toward an abyssal source. The possible connection of these waters with the magma of the greenstone is immaterial, although some basic calcic magma is the most probable source. It is to be expected that the ascending water of the region would be found not only in the greenstones, but in all the rocks which it could penetrate. The ascent of water of this kind along vertical passages, and the consequent addition of a common ion: to the circulating sedimentary salt solutions, would explain the precipitation and localization of the "giant, concretionary" salt plugs of the Gulf Coast, without making the ex-excessive demand for an improbable quantity of salt in the adjacent sediments that is required by the unmodified theory of Harris. With-out such a precipitating medium most of the dissolved sodium chloride would have been lost by passing on to the surface without precipitation. The base to which the chlorine ions were attached is immaterial, providing they were sufficiently concentrated, but the presence of the chlorides of calcium and magnesium in the solutions is indicated by the associated bodies of secondary dolomite.

Jan 4, 1915

By J. E. Burke

THE origin of so-called annealing or recrystalli-zation twins in face-centered-cubic metals continues to be a matter for speculation, and in the present report an attempt is made to explain their origin and to account for at least a majority of the observations concerning their behavior. The fact that annealing twins are prominent only The speelmen was deformed 8 pet in compression and then indented over the lower left-hand corner in a Rockwell in-denter, and then annealed to cause partial recrystallization. Note intense twinning in heavily deformed part and slight twinning in less deformed part. The upper right-hand corner is unrecrystalized. Area reduced approximately 25 pot for reproduction. after recrystallization suggests that deformation may be necessary for their formation. In 1926, Mathewson1 reported the observation by Phillips that annealing twins are frequently parallel to strain markings which delineate octahedral planes in the deformed (and partially recrystallized) matrix, and suggested that strain markings are mechanical twins which grow into annealing twins during recrystallization. Later work by Burke and Barrett' has shown that strain markings are traces of planes upon which slip has occurred, and that there is no evidence for the formation of mechanical twins of microscopically resolvable width in face-centered-cubic metals. Mathewson3 has pointed out, however, that slip may produce twin faults, and later modifications of this hypothesis have assumed that twin faults rather than true mechanical twins serve as the nuclei for annealing twins. Carpenter and Tamura5 suggested, also in 1926, that annealing twins might form by accidents of growth. A close-packed layer of atoms can be added to the octahedral plane of a face-centered-cubic metal in two possible positions, the right position

Jan 1, 1951

By Bradley Stoughton

PROMINENCE has been given lately in engineering circles to the question whether an organisation with manifold interests can be as effective as one with a single aim, especially if that single aim be the furtherance of affairs of moment and the welfare of engineers in general. In its earlier days, the A. I. M. E. was forbidden by its constitution to engage in non-technical public affairs, but the members altered the constitution in this respect, in the year 1912, in response to the growing demand that engineers be more human in their interests and that the engineering societies represent them in this respect. Since that time, the activity of mining engineers in public affairs has been growing rapidly, and we are happy that the Institute has been able to render very valuable economic services. Doubtless the greatest public service rendered by engineers in a recent great emergency was the work of the Naval Consulting Board, without which the U. S. Navy would never have been able to enter promptly into service upon our entrance into the war, ,and both Navy and Army would have been a long time without the munitions that came at an early date. We can never forget that this Board was established through the direct activity of the then President of the A. I. M. E., with the hearty cooperation of other national organizations.

Jan 1, 1920

By Ellen H. Richards

The water-supply of a country may be considered from three points of view: (1) its abundance and availability for agricultural purposes; (2) its chemical properties in their relation to manufacturing purposes; and (3) its quality and quantity as affecting domestic consumption. This paper concerns only those characteristics which may affect manufacturing and domestic uses. The so-called sanitary analyses deal not only with the common mineral elements found in water, but with organic matter and with those substances which, by their presence, indicate changes taking place through the agency of living organisms. Since these living organisms are frequently accompanied by others, capable, as are believe, of causing disease, the products of their action are looked upon with suspicion even when, as in the case of nitrates, that action may have taken place at a time long past. Therefore, upon the quality of the water-supply depends much of the history of a country, when rightly read, as well as much of its promise for the future. Thus, the hardness," or content of calcium and magnesium salts, gives a means of distinguishing at once between the waters traversing only igneous or other siliceous rocks and those coming from calcareous deposits. The presence of decomposing organic matter and intermediate products betrays a use of the water as the public carrier of refuse, which renders doubtful its fitness for domestic supply. In certain regions, one of the most valuable historical records is made by the relative amount of chlorine in the different waters. In the absence of rock-deposits carrying salt,, the chlorine present in rain and snow, and hence in mountainstreams and springs, appears to be derived from the air-borne, finely divided salt spray resulting from the beating of the ocean waves on the coast. If this be true, then the amount of chlorine found in a given water not contaminated with chlorides

Jan 1, 1902

By Sheldon P. Wimpfen, Ralph H. Sweefser

FOR centuries the pumping of water has been one of the chief problems to be overcome by the persistent men who win the mineral wealth of the world. Profitable operations have often been forced to suspend activities as the mine penetrated well below the water table or when sudden rushes of water were encountered. To operate below the local water level requires continuous pumping equal in volume to the amount of water flow¬ing into the mine workings. Often the water to be removed exceeds the tonnage of valuable material produced. To be above local water level is a valuable asset. Modern mining practice permits nothing short of the extraction of the last pound of profitable ore from a mineral deposit. In the days before the development of mechanical and electrical power as we know it today. water in any quantity was a major

Jan 1, 1948

By J. Leja, J. H. Schulman

FROTH flotation is usually effected by the addition of a collector agent and a frothing agent to an aqueous suspension of suitably comminuted mineral ores. The action of collectors is to adsorb onto the surfaces of minerals to be separated, sensitizing them to bubble adherence. The action of frothers has, in the past, been accepted as that of froth formation only, brought about by a lowering of the air/water interfacial tension. Substances capable of producing froth are classed1a,b according to their relative capacities for production of froth-volume and froth stability in the simple frother-water system. The purpose of this paper is to show that the surface active agents acting as frothers become effective only when there is a suitable degree of molecular interaction taking place between collector molecules and frother molecules at the air/water and solid/ water interfaces. Further, the discussion will demonstrate that the actual mechanism of adherence of an air bubble to a suitably collector-coated particle is due to the molecular interaction collector-frother. This leads to the formation of a continuous interfacial film of associated molecules, anchored to the mineral by polar groups of the collector, and enveloping the whole bubble. The tenacity of adhesion mineral-to-bubble results from the strength and the visco-elasticity of this mixed film. Some 20 years ago Christman2 postulated mutual dependence of collector and frother in effecting flotation. This view was, however, strongly opposed by Wark,3 who pointed out that an addition of frother had no effect on the value of contact angle once this was established in the solution of collector. More recent work by Taggart and Hassialis' indicated that the presence of frother, namely, cresol, leads to the immediate establishment of a contact angle on sphalerite, partially coated with xanthate, whereas an air bubble fails to make contact in potassium ethyl xanthate solution alone, even after 60 min induction time. Wrobel5 raws attention to the selectivity of frothers in flotation. Many instances of antagonistic effects of certain mixtures of frothers (or collectors and frothers) on flotation froth have been known to flotation operators and have been reported in literature. Taggart6 and Cooke7 give several examples of incompatibility of certain ratios of frothers and collectors, e.g., oleate and long-chain sulphates, pine oil and soaps. Monolayer Penetration. Properties of insoluble films produced by molecules of surface active agents orientated at the air/liquid interface are conveniently studied by the Langmuir trough technique, described fully by Adam.' Using the trough technique Schulman and Hughes" and Schulman et al.10a. b, c, d,e established the existence of molecular interactions occur- ring between certain types of surface active agents. Their experiments revealed the phenomenon of penetration of an insoluble monolayer (e.g., a film of a long-chain alcohol) by a soluble agent (e.g., sodium alkyl sulphate) injected into the substrate (water or salt solution). The degree of molecular interaction taking place on penetration is determined by changes in the surface pressure of the resulting film, changes of its surface potential and its mechanical properties (viscosity and rigidity). When the interaction takes place between both polar groups and both hydrophobic groups of the two participating amphipathic molecules a molecular complex is formed. Complexes formed on penetration of the monolayer at interfaces are not necessarily true chemical compounds: they are labile in solution, the activity and reactivity of individual components are greatly different from those of the molecularly associated complex, and on crystallization they usually separate out into components. However, when formed in the orientated state at interfaces they are found to be very stable, although some mixed films spread as monolayers of stoichiometric complexes can show further penetration by subsequent additions of the soluble component injected into the substrate.'" The degree of association between two or more types of surface active agents is very sensitive even to small changes in electric (dipole) moment of the polar groups of the amphipathic molecules as influenced by magnitude and position of neighboring ions or dipoles, their size, concentration, and stereochemistry. In addition, the molecular association is greatly influenced by concentration and type of inorganic salts in the substrate, by its pH, and by temperature. The nonpolar groups of interacting molecules greatly affect the stability of molecular complexes. Progressive shortening of the aliphatic chain of one of the reacting molecules weakens (at an increasing rate) its tendency to form stable complexes. Similarly, introduction of a double bond of cis-form into one of the reacting chains, which changes the straight hydrocarbon chain into a kinked one, or introduction of a branched chain, reduces the stability of the associated complex. Monolayer Adsorption. Using the trough technique and injecting metal ions into the substrate (water or salt solution) underlying insoluble films of fatty acids, alkyl amines, and sulphates, Wolsten-holme and Schulman11a,b,e. ' and Thomas and Schulman" have established conditions, namely, pH, concentration. and steric factors, under which molecular interactions take place between the polar groups of the surface active agents and the metal ions. These interactions are marked by great changes in the solubility and mechanical properties of the monolayer of the agent; no surface pressure increases are observed as in monolayer penetration experiments. The results of these adsorption studies, correlated with flotation experiments, indicated that in the case of fatty acids and alkyl sulphates their adsorption onto minerals of base-metals takes place by a similar

Jan 1, 1955

By M. Yokoi, K. Yoshida, T. Ishihara

The solubility of aluminum in cryolite melts has been determined by measuring the weight loss of aluminum submerged in melts contained in closed silicon nitride crucibles. The solubility in pure cryolite has also been checked with radioactive isotopes. The solubility decreases with increasing A1203 concentration, decreasing temperature, and decreasing cryolite ratio. The change of aluminum solubility in pure cryolite with the activity controlled by using Al-Ag and A2-Cu alloys supported the assumption that aluminum would dissolve in the form of monovalent ions according to the reaction 2AI + A1' —3 A1'. DURING the electrolytic production of aluminum, the electrodeposited metal redissolves in the bath in some form and is subsequently oxidized back to the former ionic state. This dissolution is believed to cause a decrease in current efficiency. Reported data on the solubility of aluminum in cryolite melts are scattered. The mechanism of the dissolution has not yet been determined, although certain tentative interpretations have been proposed. Many previous studies were performed under different test conditions. Studies were performed in open Systems and closed systems,'o and some were apparently not given sufficient time to Saturate." The solubility can be determined either analytically or gravimetrically. The analytical determination involves measurement of hydrogen gas evolved when frozen cryolite bath saturated with aluminum is treated with sodium hydroxide or hydrochloric acid. The gravimetric determination, adopted by many investigators,'-37'3>14 involves measurement of weight loss of the metal after equilibration with a known amount of salt. It appears that the former technique yields much smaller values of solubility than the latter technique. This large difference in results strongly suggests that the dissolved metal in the cryolite melt is no longer in the metallic state. In the present study, the solubility was determined by the gravimetric technique at various activities of aluminum using A1-Ag and Al-Cu alloys. An attempt was also made to determine the ionic (or atomic) state of the dissolved metal from the solubility data. 1) EXPERIMENTAL Apparatus. Preliminary tests demonstrated that silicon nitride was suitable as a container material since it is compatible to both the fluoride melts and molten aluminum. Crucibles were made from silicon powder nitrided with Nz gas at 1600°C. The good compatibility between crucible and melts is due to the near perfect nitrogenation of silicon. Only small amounts of silicon were found in the aluminum metal after the experiments. The crucible dimensions were 90 mm inside height, 38 mm ID, 105 mm outside height, and 50 mm OD. Close-fitting lids made of silicon nitride were also prepared. The crucible was placed in a close-fitting graphite crucible heated by a vertical Kanthal furnace, Fig. l. The lid and crucible are fastened tightly together by the condensation of vaporized bath in the narrow gap between them. The temperature was measured in the wall of the graphite crucible and controlled within * 5°C. The temperature difference between the measuring point and the interior of the melts was initially determined. Materials. The materials used were: Greenland cryolite (impurities CaF,, 0.5 pct; AlzO3, 0.2 pct; high-purity aluminum metal (purity 99.99 pct); A1203 and AlF, (provided by Nippon Light Metal Co., Ltd); reagent-grade NaF and CaF2; and 99.9+ pct Ag and Cu. Powdered reagents were carefully dried before use. A1-Ag and A1-Cu alloys were prepared before the experiments; their composition was checked by analysis

Jan 1, 1969

By Eric R. Morgan, J. C. Shyne

STRAIN aging is the name given to time-dependent changes which occur in the properties of cold-worked metals and alloys during storage. These changes are best observed through a study of mechanical properties, as illustrated in Fig. I for low-carbon steel. The effects of strain aging are usually regarded as being detrimental, particularly in deep-drawing steels. For example, an increase in yield strength and loss in ductility lead to buckling and tearing during drawing. At the same time the return of the yield point results in the formation of Luders bands or stretcher strains during the pressing operation. As a result of these effects many attempts have been made to eliminate strain aging from low-carbon steel. The problem still remains, however, because all known methods of preventing strain aging result in a more costly steel. The present work is an assessment of the situation in terms of theoretical, practical, and economic factors and suggests a new solution to the problem. Previous Work According to the Cottrell theory,' strain aging in a-iron may be regarded as the migration of interstitial atoms to free dislocations and the anchoring of dislocations by the resulting atmospheres. It may be concluded that the important factors which will govern the degree of strain aging are the diffusivity, the effective amount of interstitial element in solution, and the time of aging. The diffusivities and effective amounts of carbon and nitrogen in solution in low-carbon rimming steel are such that significant aging occurs in a few hours' storage at room temperature. Strain aging in deep-drawing steels cannot be controlled by controlling the time of aging because in commercial practice this is determined by economic factors concerned with inventories and may be several weeks. The diffusivity of nitrogen is twice that of carbon at room temperature but the diffusivities can be controlled by controlling the storage temperature. The retardation produced by only a 25 °C drop in temperature is significant but the cold storage of large steel inventories is an impractical solution to Table I. Analysis of Base Materials Alloy Pet C Yet 0 Pet N Vac 0.0037 0.052 0.0003 H 0.0044 0.013 0.0008 C 0.06 0.0014 0.0001 the problem. By far the most simple and effective ways to control strain aging are through control of the amount of carbon and nitrogen in solution. This may be effected through alloying, controlled precipitation, or by eliminating the carbon and nitrogen. Consider first the control of the amount of carbon in solution. The simplest approach would be alloy -ing in which strong carbide-forming elements are added. Examples of this approach are the additions of titanium' and niobium9 0 steel. These elements also combine with nitrogen and oxygen and when added in sufficient quantity result in a completely killed and non-aging steel. They are, however, impractical additions because they result in a costly steel. Carbon and nitrogen are often removed from iron on a laboratory scale by annealing in wet hydrogen, but because of cost this process has never been adopted on a commercial scale. In practice the amount of carbon in solution is controlled by the rate of cooling from the annealing temperature (710°C or 1310°F). In commercial box

Jan 1, 1958

By John C. Calhoun, Frank T. Bethel

Glass beads have been surface treated with Dri-film to render them oil wet by n-octane to varying degrees, and capillary desaturation curves have been determined by the restored state method. The desaturation curves show a regularity of increasing displacement pressures as the oil wetness increases. This has been used to compute apparent contact angles between n-octane and water on glass. The family of desaturation curves also shows a regular crossover, such that the residual wetting liquid saturation values are in reverse order to the displacement pressures. A semi-logarithmic variation is shown between the apparent contact angle and the residual saturation. The desaturation data are interpreted to mean that the wetting liquid ceases to be a continuous phase within individual pores before the capillary pressure can be raised sufficiently to force out the wetting phase completely. The saturation of wetting liquid at which this break in liquid continuity occurs is higher as the oil wetness decreases. INTRODUCTION The petroleum industry has for some time been using measurements of capillary pressures on porous media for research correlations and engineering calculations. It has been generally recognized that the capillary desaturation curve reflects the character and arrangement of the pores within the media and the distribution of fluids within the pores. Methods have been proposed for computing pore size distributions, tortuosity factors. and relative permeabilities from capillary desaturation data.' There is little doubt that the interactions between porous rocks and their contained fluids resulting from surface forces play a dominant role in determining the magnitude and direction of capillary pressure measurements. There have been attempts to introduce as variables two quantities — inter-facial tension and contact angle — generally used to char- acterize surface forces, but in spile of the wide interest in these quantities as important variables, few definite conclusions have been drawn concerning their qualitative or quantitative significance. INTERFACIAL TENSION The interfacial tension appears in a capillary pressure function given by Leverett for correlating capillary desaturation type curves. Use of the interfacial tension in this function seems to be justified by other experiments reported. Apparently, interfacial tensions have little bearing on wetting phase residual by desaturation. CONTACT ANGLE The contact angle was utilized as a variable by Bartell and co-workers"." in tests on displacement pressures, later recognized as the initial point of capillary desaturation. Although Leverett did not include contact angle in his original formulation of the capillary pressure function, later workers suggested its addition. Few reports are available to show variation of residual liquid with contact angle as a result of capillary desaturation.' The problems attendant to measuring contact angle within a porous medium are great. As a consequence of the lack of a concrete approach to a measurement. the workers in this area of research have adopted the general expression of "wettability" to indicate the relative position of two liquids saturating a porous body. It has been shown that gross measurements on porous systems, including capillary desatura-tions, are sensitive to wettability. Attempts at giving a scale to wettability in terms of contact angle through capillary desaturation curves have been made and these apparently are steps in the right direction. In these attempts presence of many other variables precludes attainment of exactness. Also, as a result of other variables, it has been impossible to correlate changes in apparent contact angle with changes in other physical measurements of the systems in question. The present work is an attempt to eliminate as many variables as possible in measuring capillary desaturations resulting from changes in contact angle within a porous medium.

Jan 1, 1953

By Lewis T. Wright

IT is commonly believed by metallurgists that in copper-smelting, the copper in the slags, which is irreducible by continued smelting, is retained in the form of "prills" of matte. I have frequently held well-settled slag in a molten condition for a long period without being able thereby to reduce the copper-content. The slag acted as though it contained a minimum of dissolved or combined copper that could not be settled out by gravity. I have used reagents, but without satisfying myself in what form this copper existed. The same slags, by fine grinding and elutriation, could not be separated into portions containing more or less copper than the average content. By treating copper-slags in an electric furnace an impure button of copper. was produced, but the high temperature and the strong reducing-action of the furnace were influences that suggest an explanation of a result not obtainable with ordinary smelting-temperatures. If all the copper in the slag were in the form of copper-matte, and not existing as a dissolved compound with some of the elements of the slag, then the other metals in the matte, such as gold and silver, should occur in the slag in the same ratio to the copper as to the copper in the accompanying matte. This reasoning led me to study the ratio of metals in the products of smelting, and, apart from the issues discussed in this paper, the research has proved both interesting and illuminative. On the assumption of a similar ratio of metals in matte and slag, if the percentage of copper in the slag accompanying; a matte containing 50 oz. of silver and 1 oz. of gold per ton of copper was 0.3 per cent., or 96 oz. per ton of slag, there should be found 0.15 oz. of silver and 0.003 oz. of gold per ton of slag:; but, in my experience, there is less silver and much

Sep 1, 1909

By Frank A. Wilder

The most important process in a gypsum mill is calcining the crude mineral. There seems, however, to be little progress or change in calcining methods. This would not be surprising if the industry was not, in other ways, developing. The demand for gypsum in its various forms, however, is growing rapidly. The output has more than doubled in six years, while the value of gypsum products, through the introduction of higher priced. specialties like wall board, has nearly trebled in the same period. In other industries, under somewhat similar conditions, calcining in rotating cylinders, either by direct or indirect heat, has replaced the method that still prevails in gypsum mills. Efforts were made to use rotary calciners in manufacturing plaster of Paris in the early days of the industry in America; 25 years ago rotary calciners were in use in Germany. At that time there was great diversity of opinion in regard to their merit. In 1923, the output of calcined gypsum in the United States was 3,101,378 tons. About nine-tenths of this material was calcined in kettles, the remainder in rotary calciners. The ratio was about the same 10 years ago. During these 10 years, rotary calcining made relatively no gains, and there were no important changes in the construction of kettles. In their manipulation, the only change of consequence was in connection with the length of time that the gypsum is left in the kettle. For wall-plaster purposes, all producers who had not previously done so changed from second-settled to first-settled calcined gypsum, thereby reducing production costs and improving the plasticity and sand-carrying capacity of their plaster. Nevertheless, in the few mills in which they were installed, rotary calciners continue to operate, with possibly one or two exceptions, and to be highly successful. In these 10 years, the Cummer type of rotary calciner has disappeared. All rotaries now used are of the cement-mill type with a diameter of 6 or 7 ft. and length of 80 to 120 feet.

Jan 1, 1925

By J. R. Bell, W. J. Childs, J. H. Bucher, G. A. Wilber

A technique for determining recrystallization times as short as 0.10 sec was developed utilizing the "Gleeble", a commercially available testing system designed for the study of short-time, high-temperaLure themal and mechanical processes. The procedure consisted of heating a small tensile specimen to a given temperature of hot deformation, loading to a given reduction in area, unloading, delaying various intervals at temperature, and then reloading- to failure. The magnitude of the ultimate load obtained upon reloading decreased with delay lime as recrys-lallization proceeded. The technique was applied to austenite recrystallization in AISI 1010 and AISI 1010 uith 0.02 pct Cb steels. For each steel the reduction in area given the specimen on the first pull was mainlairred at 30 ± 5 pct and recrystallization times deterntined at various temperatures. The results indicaled a significantly slower rate of recrystallization for the columbium-modified composition, suggested the presence of- a recovery stage in the softening process , and indicated a greatly increased softening rate at a temperatuve where significant allotropic transformation to a partially ferritic Structure could occur. In recent years increasing attention has been paid to the fact that the process of recrystallization of austenite deformed at elevated temperatures is far from instantaneous at many practical hot-working temperatures.1-3 This realization has given rise to such terms as hot cold-working1 or warm-working,2 These terms generally describe processes where the recrystallization rate at the temperature of deformation is slow enough to have an appreciable effect on mechanical properties despite a relatively high deformation ternperature. The mechanical properties of interest can be either the properties at the deformation temperature as in hot-workability studies4 or the room-temperature properties after cooling as in the many recent studies of various thermomechanical processes172 where heat treatment and deformation are intentionally combined to give a unique set of room-temperature properties. Because of this interest in processes where the austenite recrystallization kinetics can be an important variable, the development of quantitative methods of following the course of short-time, high-temperature recrystallization has received increasing attention.l,3,5 The experimental methods to date have, in general, relied upon rapidly deforming the austenite, holding at temperature for various brief intervals, quenching as G.A.WILBER and W. J. CHILDS, Members AIME,are Research-Fellow and Professor, respectively, Rensselaer Polytechnic Institute, Troy, N. Y. J. R. BELL and J. H. BUCHER, Member AIME, are Research Engineer and Research Supervisor, respectively, Graham Research Laboratory, Jones & Laughlin Steel Co., Pittsburgh, Pa. Manuscript submitted March 13, 1968. IMD. rapidly as possible, and then using room-temperature measurements to follow the recrystallization process. Although such methods can be successfully applied to certain alloy steels, the existence of the allotropic transformation during cooling of plain-carbon or low-alloy steels tends to obscure the results. Thus, such room-temperature measurements as hardness and X-ray line widths do not correlate well with the extent of austenite recrystallization before quenching,5 and results based on room-temperature microstruc-tural observations are dependent upon the success in correlating the observed structure with the prior aus-tenitic grain structure.1,3,5 The purpose of the present work was to develop a quantitative method for the determination of short-time, high-temperature recrystallization rates, based on measurements made at the temperature of deformation. EXPERIMENTAL TECHNIQUE The basic technique consisted of heating a small tensile specimen to a given temperature of hot deformation, loading to a given reduction in area, unloading, delaying various intervals at temperature, and then reloading to failure. The data were obtained in the form of traces of load and elongation as a function of time. Due to the high deformation temperature, the strain hardening introduced during initial loading was progressively annealed out with holding time after unloading and the loads obtained upon reloading decreased as this softening proceeded. Although the value of the second load at any Consistent point On the load-elongation curve could have been used as a measure of the degree of softening, the most convenient to use was the ultimate load. The softening indicated by the decrease in the second ultimate load with time is essentially a process of annealing of cold-worked material at a high deformation temperature. Although some recovery grain growth may contribute to such a softening process, it is generally considered that the major softening which must take place to achieve complete removal of substantial Strain hardening will occur by the formation of new, stress-free grains. As the results of this work indicate that essentially complete removal of strain hardening did in fact occur. the primary softening process will be attributed to recrystallization, and specific reference made where it appears that other mechanisms may be contributing to the total observed softening. It would, of course, be of interest to attempt to correlate the results of this work with the actual austenite fraction recrystallized as determined by other techniques. This was not attempted in the present work because it would have required running a large number of additional specimens and, as discussed previously, there is limited assurance that the results would accurately reflect the prior austenite fraction recrys-

Jan 1, 1969

By C. W. Spencer, K. A. Semlak, F. N. Rhines

IN an effort to obtain a better understanding of sintering in the presence of a liquid phase, it was decided to study the rate of capillary rise of a relatively low melting liquid metal in a higher melting metal powder compact. By assuming that the metal powder compact consists of a great number of parallel capillary tubes and that the flow of liquid

Jan 1, 1958

By P. H. Dudley

IN giving a brief account of the experiments in progress to inquire into some of the facts in regard to "railway resistances," recently commenced upon the Lake Shore and Michigan Southern Railway, with the dynagraph (which is essentially an instrument recording upon paper the force required to draw a train, at all speeds, marking the time in short intervals, so that the force absorbed due to any

Jan 1, 1876

Jan 1, 1881