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By A. E. Worthington, R. F. Meldau

An analog computer study was made of the reduction of the magnitude of the SP by formation geometry and resistivity effects. Practical field .situations were studied. The analog data were converted to the form of departure charts. These charts may he used to determine the reduction in the SP due to the above eflects pith good precision Quantitative interpretation of the SP log in terms of formation water resistivity is presently based on the premise that the observed SP is equal to the electrochemical potential developed across a shale between the mud filtrate and the formation water. This procedure inherently assumes that, first, no electro kinetic (streaming) potential is present, and, second, that the SP is not reduced by resistivity or geometry effects in the formation. When, however, such a reduction of the observed SP does occur, one may write, SP = b,E, b, E, (1) where SP is the observed self-potential opposite the center of the bed under consideration. In this case, E, is the electrochemical potential, E, is the electrokinetic potential, b, is the electrochemical reduction factor, and h, is the electrokinetic reduction factor. The first assumption above is equivalent to assuming E, = O in Eq. 1 and the second assumption is equivalent to h, = b, = 1. Examination of electric logs shows that for many formations of interest the observed SP is reduced below its maximum value. The object of this work is to aid quantitative SP interpretation in at least some of these situations by obtaining values for b, and b, in Eq. 1 as functions of realistic combinations of bed thickness, depth of invasion, and formation resistivity. The only previously published work in this field known to the authors is by H. G. Doll' in 1948. He evaluated b, under conditions permitting exact analytical solution. His work clearly established the importance and qualitative nature of formation geometry and resistivity effects upon the SP, but the necessity of obtaining analytical solutions restricted his study to situations of limited practical interest. In order to extend such studies to practical combinations of formation parameters which do not lend themselves to feasible analytical solutions, the results reported in this paper were obtained by use of a special analog computer. THE ANALOG MODEL The analog model used for this study was the Guyed Analog Computer which originally was designed and built for resistivity log departure curve studies. It consists of a two-dimensional mesh of resistors, with the vertical mesh corresponding linearly to vertical distance along the borehole, and the horizontal mesh corresponding to radial distance from the borehole axis. By proper choice of horizontal resistor values, a three-dimensional, axially symmetric, borehole-formation problem can be modeled with this two-dimensional array. These and other details of the model are contained in a paper by H. Guyod'. The geometry used for the SP studies with the analog is depicted in Fig. 1. This configuration has a horizontal plane of symmetry, and, hence, the model, and the following discussion, need only to be concerned with one quadrant such as shown in Fig. 2. A further simplification arises by considering that both the natural potential sources and those used in the model have fixed internal impedance. Therefore, the current flows produced by these sources can be separated and studied independently ( i.e., the superposition theorem can be applied). SP = SP, i SP, = h,E, + b,E, ,(7)

By R. P. Agarwala, M. S. Anand

Using residual activity technique, the diffusion of palladium, silver, cadmium, indium, and tin in alunzinum has been studied in the temperature range of 400" to 630°C. The diffusivities (in units of square centimeters per second) have been expressed as: IMPURITY diffusion in aluminum,1-9 silverand lead5 for cases of low solid solubility of the impurity in the host metal has yielded frequency factors in the range of l0-6 to l0-9 sq cm per sec whereas the activation energy is practically half the self-diffusion activation energy value. From the observed values of frequency factor, activation energy, and entropy of activation, it has been suggested' that these solutes are not diffusing by vacancy or interstitial mechanisms but by a mechanism which should be consistent with such low values of the diffusion parameters (Do and Q). However in spite of extensive work on these types of systems, the mechanism of diffusion is still not well understood. The present investigation on the diffusion of palladium, silver, cadmium, indium, and tin in aluminum has been carried out to throw further light on the diffusion mechanism in systems, where the solid solubility is very low (except for the case of silver). The results are discussed on the basis of solid solubility and the structural changes involved owing to the presence of the solutes in aluminum solid solution. An attempt has also been made to apply the existing theories of charge5-8 and size8 difference between the solute and the solvent. EXPERIMENTAL PROCEDURE Specimens (1/2 in. diam by 3/8 in. high) were machined out of pure aluminum (99.995 wt pct) rod obtained from Johnson Mattheys. They were sealed under vacuum in quartz tubes and annealed at 620° C for several hours; the grains thus developed were sufficiently large to eliminate the possibility of diffusion along the grain boundaries. The flat ends were prepared carefully after polishing as described previously,10 Radioactive nitrates of cadmium, indium, and tin and chloride of palladium containing, respectively, cd115, 1n114, sn113, and pd103 were dissolved in distilled water and mixed with 30 pct acetone. By means of a micropipet a drop of this solution was placed on a smoothly polished and lightly etched surface of the specimen. Due care was taken to see that the solution spread uniformly on the surface of specimen without trickling down its sides. Radioactive silver was elec-trodeposited using a AgCN-KCN bath. The amount of sample deposited in all the cases was not more than 0.1 µ thick. The samples were then sealed in quartz tubes in vacuum. The cadmium samples were sealed in a purified argon atmosphere to avoid evaporation. The samples were then diffusion-annealed. The temperature of annealing varied between 400° and 630°C and was controlled to ±5°C. On heating to -400°C,the deposits of cadmium, indium, and tin, which were of the order of 0.1 p in thickness, were converted to their respective oxides. The contribution of oxygen present in the lattice of aluminum due to these oxides has been calculated and found to be less than 10 ppm in all cases. Oxide method has already been used by other workers11'12 in diffusion studies without any controversy on the issue. However, in some of these investigations, metallic deposition was also tried. The diffusivities calculated from these measurements were found to agree very well with the diffusivities obtained by using the oxide method. Thus it is assumed that the measured diffusivities represent true diffusion coefficients. Since palladous chloride decomposes at about 500°C, the deposited samples which were to be diffusion-annealed below 500°C were heated in vacuum for a very short time at 500°C to allow the decomposition of palladous chloride to palladium metal. Time taken in decomposition of nitrates to oxides and chloride to metal was negligibly small as compared to the period of the diffusion anneals. The residual activity technique13 was used to study the diffusion profiles where thin layers from the specimen surface were removed by grinding it parallel to a flat surface on a 600-grade carborundum paper. The specimen was washed, dried, and weighed, the differ -ence of the weight being the measure of the thickness of the layer removed. After each such abrasion and weighing, the total residual activity on the surface of the specimens was measured by counting 0.656, 0.94,

Jan 1, 1968

Jan 1, 1897

By L. C. Uren, E. J. Bradshaw

This paper presents the results of a group effort by a number of University of California students and faculty members, and the authors attach their names primarily in the capacity of editors and interpreters of the data thus assembled. In addition to the writers, the following individuals have made substantial contributions in time and effort in the conduct of this research: Dr. A. J. Carlson, Associate Professor of Petroleum Engineering; J. E. Gosline, University Research Assistant; C. F. Bedford, G. W. Mikulasek and H. S. Conder, senior and graduate petroleum engineering students; H. Bachman, G. Spencer and G. W. Gard, mechanicians in the Department of Mining and Metallurgy. Acknowledgment is also due the Research Board of the University, the Department of Mining and Metallurgy, and Prof. F. H. Probert, Dean of the College of Mining, for continued cooperation in securing mechanical assistance and funds for the purchase and assembly of apparatus. Significance of the Pressure Gradient The expulsion of petroleum from its reservoir sand doubtless is due to expanding natural gas intimately associated with the oil, to the hydrostatic pressure of encroaching edge waters, and to gravitational influences. These forces may operate independently or collectively. In any case they subject the fluids stored within the reservoir sands to elevated pressures, thus causing movement of oil and gas through the productive formations toward the lower pressure of the well outlets. This movement is opposed by pore friction, capillarity and adhesion: resisting influences brought to bear by the reservoir sand on the moving fluids. The magnitude of the resisting force is influenced directly by the viscosity, surface tension and density of the oil, as well as by the properties of the gas. The more rapid the rate of flow, the greater will be the resistance offered, and the greater will be the energy consumed.

Jan 1, 1932

By C. H. Mathewson

COPPER and the copper-base solid solutions readily form twin crystals when plastically deformed at a suitably elevated temperature or annealed after cold deformation. In fact, no feature of the microstructure of these materials is more prominent or characteristic than these straight-sided bands or simple lines of division which sometimes come from groups of thin polysynthetic lamellae, penetrating part way or wholly through the parent grain substance, but often divide the grain into a few or perhaps only two crystallographically related parts. Nearly always the bands as seen in the usual microscopic examination of a specimen come into vivid contrast with the adjacent crystalline material owing to the inherent difference in orientation. Bands which under special conditions of orientation cannot be seen with vertically incident light are often visible under oblique illumination and, when this fails, contrasting effects usually may be obtained by using polarized light. There is no longer any doubt that these synthetic banded structures obtained in the ordinary course of working and annealing are due to twinning of the spinel type which was observed long ago in a number of metals crystallizing in the isometric system.1 It has been customary in metallurgical literature to designate these synthetic twins, which grow into prominence during an annealing process, as "annealing twins" without regard to the actual mode of their formation, which is, indeed, obscure and with scant recognition of the fact that prior deformation is essential, no twins having been observed in metal of known unstrained history. This is questionable; especially in view of. the fact that in a number of metals and minerals, reorientation into the twin configuration is known to occur as a result of a simple shearing mechanism along the recognized twinning planes and the

Jan 1, 1930

By R. W. Diamond

THREE mills are now operated by the Consolidated Mining & Smelting Co. of Canada, Ltd:: (1) The Sullivan concentrator, Chapman, B. C. (near Kimberley, B. C.), (2) the St. Eugene concentrator, Moyie, B. C., and (3) the Tadanac (customs) concen-trator, Trail, B. C. Differential flotation is the only concentration method employed in all three plants. Tables are used for pilot work only. Flotation equip-ment and control are similar in the three mills, and the flow sheets at the St. Eugene and Tadanac mills, while much simpler, are modeled after that of the Sul-livan concentrator. Successful differential flotation of Sullivan ore com-menced in the spring of 1920, in the pilot concentrator at Trail. During 1920, 193,804 tons were treated by this process. This operation continued without interrup-tion and with steady growth. For the first 7 months of . 1923, which concluded the pilot plant operation, ap-proximately 1100 tons were treated daily. I believe the Sunnyside plant of the United States Smelting &. Refining Co. was the only successful and large scale operation practising differential flotation prior to 1920. in North America. The Sullivan ore, because of its high iron content, was quite a different problem from that at Sunnyside. The entire tonnage of Sullivan ore had to be separated into three sulfide concentrate products-lead concentrate, zinc concentrate and iron concentrate. The choice and arrangement of equipment, and the original flow sheet for the Sullivan concentrator were controlled by the results of the exhaustive pilot mill test. These covered a continuous period of 3 1/2 years and involved the treatment of 1,076,368 tons of Sullivan ore. Satisfactory recoveries are made from feed; 11.0 per cent lead and 7.5 per cent zinc in the form of lead concentrate containing 69 per cent lead, 4.5 per cent zinc, and zinc concentrate containing 3.0 per cent lead and 49 per cent zinc. (The pure zinc mineral in Sulli-van ore is marmatite, 'containing approximately 54.5 per cent zinc and 10 per cent iron. It is apparent, there-fore, that 49 percent concentrate is high grade for this particular ore.)

Jan 8, 1927

By P. G. Shewmon, W. M. Robertson

The derivative of the surface tension with orientation, ??/??, for copper has been measured over the entire unit triangle. This derivative or torque term was determined from the variation of the dihedral angles at the intersection of twin boundaries and free surfaces. High-temperature anneals in graphite with a hydrogen atmosphere gave torque terms of 0.097 at (111), 0.066 at (100), and 0.0257 at (110). A variation from -36oto +23oC in the dew Point of the H2 had no effect on these values, nor did a change from 99.98 to 99.999 pct Pure copper. The removal of graphite from the system decreased ??/?? slightly. Considering the surface near a low-index plane to be smooth except for occasional steps, the free-energy increment per cm of step is calculated, and it is shown that the observed variation of ??/?? is consistent with a random distribution of steps and an interaction energy between steps. Integration of ??/?? gave the relative values of y at (100), (110), and (111) as comPared to ymax: (Y111/Ymax) =0.974, (Y110/Ymax) =0.996, (y100/Ymax) = 0.983. The ratio of the surface tension of coherent twin boundaries to the surface tension of the free surface was found to be (yT/ys) = 0.027 * 0.011. In a crystalline solid the surface tension y (surface free energy per unit area) depends on the orientation of the surface relative to the crystallographic axes of the crystal. Measurements of this variation of y with surface orientation have been reported for metals only within the last few years. Consider the grain boundary groove shown in Fig. 1. Here the three surfaces are all normal to the plane of the paper, and each has a different surface tension, y1, y2, and y3. If the system is at equilibrium, the total surface free energy must remain unchanged for a slight vertical displacement of the intersection (points A, B, and C are kept fixed). As shown by Herring,' the following equation is obtained:

Jan 1, 1962

By R. L. Slobod, C. Gatlin

This .study defines the basic mechanism of the mis-cible displacerrzent of oil and writer from porous Medici by various water-driven alcohol .slugs. Three distinct alcohol slug processes were .studied. Considerable data concerning the quanity of alcohol required for oil recovery were also obtained. All data were obtained in a 1-in. diameter, 100-ft long, unconsolidated core. The porosity of this system was 35 per cent. and the permeability was approxitrlately 4 darcies. Total core pore volume wax 5,716 cc. All displacements were conducted at a constant injection rate of 5 to 6 cc//min, which corresponds to a frontal advance of 5 ro 6 ft/hr. The first portion of this paper is concerned with 111 use of one alcohol—isopropyl—a\. the slug material. Isopropyl alcohol (IPA) is completely miscible with both oil rind water; however, miscibility of the threc-component systems, oil-water-IPA, requires a relutively. high concentration of IPA. Hence, the displocement is not of the misoible type unless the IPA concentration is maintained above some critical value. A slug of IPA equal to only 13.5 per cent of the pore volume was jound to be sufficient to obtain complete recover?, of residua1 naphtha. In later studies two distinct process variations were developed. The firsr of these utilized methyl alcohol (MA) and IPA as slug materials. It was shown that methyl alcohol may he substituted for IPA at the front and rear of the slug with no loss of oil recovery. A .slug of 4 per cent MA-4 per cent IPA-4 per cent MA was sufficient for complere oil recovery. Because MA is considerably cheaper than IPA, this represents an important step toward economic application. A .second process variation used normal butyl alcohol (nBA) and MA as the composite slug, the nBA segnzent being injected first. This technique requires the smallest total slug size (approximately 10 per cent) of all processes studied. The high cost of nBA, however, precludes commercial application. It is possible that this basic process, subject to changes of alcohol type, may lead to a commrercicil process. INTRODUCTION Within the last 10 years, considerable study has been devoted to the general mechanics of miscible phase dis- placements in porous media. These studies have. in general, dealt with two-component displacernent. All reported field trials to date have been modified gas drives of one type or another. These utilize either lean gas at high pressure, rich gas at lower pressure or an LPG slug. The irreducible water content of the reservoir remains immobile during these processes. Although these techniques hold great promise. certain drawbacks do exist. Poor areal sweep efficiency, inherent in any displacement having a highly unfavorable mobility ratio, is one disadvantage. Furthermore, the miscibility of all processes which use gas is dependent on pressure. These pressure limitations may prohibit application to shallow reservoirs. There are also many areas where large quantities of LPG and natural gas are not readily available. These factors emphasize the need for improved techniques. The alcohol slug process is also a miscible-phase displacement process. It differs from the previously mentioned two-component techniques, however, in that both the reservoir oil and water are displaced by the slug. This behavior is a consequence of the miscibility of certain oil-water-alcohol systems. In the simplest case, a relatively small volume (slug) of an alcohol (such as isopropyl) is injected into the system. Water is then used to drive the slug through the medium. Thus. three components—-alcohol. oil and connate water-—exist at the front side of the slug. Miscibility is obtained at some alcohol concentration, this being dependent on the solubility of the particular system. Miscibility is maintained within the slug until the alcohol concentration falls below that value required to maintain miscibility. When miscibility is lost, the process reverts to a water flood. Certain inherent benefits of this technique are apparent. High pressures are not necessary to obtain miscibility in these liquid systems. Furthermore, water is a more desirable driving agent than gas because of the improved mobility ratio and the attendant improvement in areal sweep efficiency. The main disadvantage is, of course, the relatively high cost of alcohols. The use of an alcohol slug to recover reservoir oil is not a new idea." ' However, this process has received only limited study, presumably due to the lack of industrial interest caused by the seemingly prohibitive cost of alcohols. The main purpose of this study was to investigate the mechanism of the displacement of oil and water by various alcohol slugs and to develop process modifications aimed toward possible commercial application.

By Samuel M. Cassidy

The exact date of man's first use of coal is lost in antiquity. The discovery that certain black rock would burn was undoubtedly accidental and probably occurred independently and many times in the world over thousands of years. It is quite likely that these independent discoveries were made when primitive man chanced to build camp fires on exposed ledges of a black stone, then was amazed when it caught fire. The Chinese recorded the use of coal 1100 years before the Christian Era. And, from the Bible we learn that King Solomon was familiar with coal in what is now Syria. In Wales, there is evidence that the Bronze Age people used coal for funeral pyres, and it is known that the Romans used this fuel. There are other ancient references. So the knowledge that coal would burn, and even some uses of that knowledge, goes back for thousands of years. However, practical and consistent use of coal seems to date to England in the Middle Ages. COAL IN AMERICA In the Americas, there is evidence here and there of a slight use by the Indians. However, the first recorded discovery of coal, in what is now the U.S., was by French explorers, who reported a "cole mine" on the Illinois River in 1679. Following this, other discoveries were made by French and British explorers, but the first recorded actual usage was in Virginia in 1702, where a French settler was granted permission to use coal for his forge. Earliest recorded commercial mining was in 1750, from the James River coalfield near Richmond, Va., a deposit now abandoned. Besides local consumption from this field, shipments were made to Philadelphia, New Pork, and Boston. During the Revolution this coal was of importance in the manufacture of shot and shell; so important, in fact, that the British sent an expedition in 1781 to destroy the iron works and

Jan 1, 1973

By P. E. Rider, K. A. Gschneidner, O. D. McMasters

The solid solubilities for thirteen rare-earth metals in gold were determined by using the X-ray parametric method. Solubilities ranged from 0.1 at. pct for lanthanum in gold up to 8.8 at. pct for scandium in gold. The solubilities from lanthanum to gadolinium were very small and essentially constant, but a sharp increase occurred from gadolinium to scandium. The large solubilities for the heavy rare-earth metals were not expected because of the large size and electrochemical differences between rare-earth atoms and the gold atom. Contributions from first- and second-order elasticity theory plus an electronic contribution were found to reasonably account for a more favorable size factor. Electron transfer from the rare-earth metal to the gold Is thought to occur such that the resultant rare-earth and gold electronegativities are favorable for solid-solution formation. It was also found that this mutual adjustment of size and electronegutivity does not occur if the pure-metal size factors are greater than a critical value of 25 pet. The eutectic temperatures for ten systems were determined and these remained fairly constant at approximately 809 "C for the lighter lanthanide metal-gold systems until the Er-Au system was reached, at which Point the eutectic temperature successively increased reaching a maximum of 1040°C in the Sc-Au system. This rise was correlated to the size factor becoming more favorable for solid-solution formation at erbium. The valence state of ytterbium was found to change from two in the pure metal to three when ytterbium is dissolved in the gold matrix. RECENT results1 reported concerning the solubility of holmium in copper, silver, and gold, showed that the solubility of holmium in gold was quite large, 4.0 at. pct, compared with 1.6 in silver and 0.02 in copper. The small solubilities of holmium in silver and copper are quite reasonable in view of the large size difference (22.2 and 38.2 pct, respectively), large electronegativity difference (0.59 for both systems), and possible unfavorable valency factor (assuming one for silver and copper and three for holmium). The large solubility in gold, however, is unexpected because these same factors are also unfavorable for holmium and gold (22.5 pct size difference and 0.69 electronegativity difference), and because the light rare-earth metals, lanthanum, cerium, and praseodymium, have negligible solid solubilities in gold.2 In view of this unexpected behavior, it was felt that a study of the solid solubilities of most of the rare-earth metals in gold would be desirable to better understand the factors involved in the formation of solid solutions. Of the rare-earth metals added to gold in this study, only ytterbium is divalent in the pure metallic state (the other rare-earth metals are all trivalent) and many of its physical properties (such as the metallic radius, electronegativity, and so forth) are much different from those of the normal trivalent rare-earth metals.' The properties of ytterbium are such that one would expect solid-solution formation to be less favorable for ytterbium in gold than for any of the normal trivalent rare-earth metals. But chemically ytterbium is known to possess a stable trivalent state, and it is quite possible that ytterbium may alloy as a trivalent metal under certain conditions rather than as a divalent metal. Because of the dual valency nature and because so little is known about the alloying behavior of ytterbium, the gold-rich ytterbium-gold alloys are of special interest. EXPERIMENTAL PROCEDURE Materials. The gold used in this investigation had a purity of 99.99 pct with respect to nongaseous impurities. In general the rare-earth metals were prepared by reduction of the corresponding fluoride by calcium metal.3 The impurity contents of the metals used in this study are given in Table I. Preparation of Alloys. Two- or 3-g alloy samples were prepared by arc melting. The samples, with the exception of some of the Er-Au alloys, had weight losses of 0.5 pct or less. All alloy concentrations noted in this paper are nominal compositions. After arc melting, the alloys were wrapped in tantalum foil, sealed off in quartz tubing under a partial atmosphere of argon, homogenized for approximately 200 hr at 780°C, and then quenched in cold water. X-Ray Methods. The X-ray parametric method was used in determining the solubility of the rare-earth metals in gold. filings were sealed in small tantalum tubes by welding under a helium atmosphere. The tantalum tubes were then sealed in quartz tubing under a partial argon atmosphere, and annealed for times ranging from 1/2 to 3 hr (the length of time was inversely proportional to the an-

Jan 1, 1965

By Robert P. Roberts

In order to obtain data on the thermal effect of the blast-furnace jacket and on the water consumption in these jackets a series of tests were run on the 56 by 180 in. blast furnaces at the Great Falls Reduction Department of the Anaconda Copper Mining Co., at Great Falls, Mont. The arrangement of the jacket is shown in the transverse section of one of the furnaces (Fig. 1) on which the tests were made. The nose, spout, and breast jackets have independent water supplies and discharges. The end and side jackets are connected in pairs, as regards water supply, the feed water entering at the bottom of the lower jacket and overflowing into the bottom of the jacket immediately above it, and discharging into an independent overflow pipe for each pair of jackets. Tests were run on the main side and end jackets, the breast jacket, the spout, and the nose. Measurements were taken of the quantity of water discharged per minute and the rise in temperature of the water in its passage through the jacket. The product of these two results, expressed in the proper units, evidently gives the number of units of heat removed per minute by the water. Sufficient work was done on each type of jacket to determine its behavior under different conditions, and the results from each set of conditions were checked by repeating the work from three to six times. The method used was as follows: The overflow from the jacket to be tested was arranged to discharge at will into a barrel, mounted upon platform scales. The discharge temperature was read just before turning the water into the barrel, and just before turning it back to the sluice; if the test lasted more than a minute, additional temperature readings were taken at 1-min. intervals from start to finish. The elapsed time of running the water into the barrel was determined with a stop-watch, and this figure, combined with the in-

Jan 1, 1914

By AIME AIME

LEROY SALSICH has had 37 consecutive years of operating and executive experience in the Lake Superior iron region during 35 of which he has been a member of the A.I.M.E. His recent election as an institute Director to represent the iron and copper country therefore brings to the Board a man long known throughout the area that he represents and well acquainted with the history of the Institute. Mr. Salsich is a native of the area in which his professional life has been spent, having been horn at Hartland. Wis., and graduating from the state university's college of engineering in 1901. A call had come to the college from the Lake Superior Consolidated Iron Mines, at Duluth.

Jan 1, 1938

By C. A. Stickels, C. M. Yen

Secondary recrystallization was investigated in vacuum-melted electrolytic iron to which 70 pm N was vacuum-meltedadded. The secondary texture is "near {554}<225>" for material cold-rolled 75 to 90 pct, the sharpness of the texture increasing with increased rolling reduction and with decreased annealing temperature. At reductions of 95 and 97.5 pct the secondary texture is &apos;"near {322)(296)". Both secondary orientations also exist as major components of the primary re-crystallization texture. Development of a strong "near {554) (225)" secondary texture appears to depend on the evolution of the Primary texture to a transition texture depleted in orientations near the secondary orientation before the onset of secondary growth. A variety of qualitative experinzents have been used to show that nitrogen is important in limiling primary grain growth. The presence of nitrogen does not seem essential for the establishment of a transition texture, but a loss of nitrogen during annealing may facilitate growth of grains in the secondary orientation. Secondary grains we shown to form initially at the specimen surface. This is not thought to indicate that surface energies are important in the growth process. It is proposed that the quasi-two-dimensional character of surface grains permits discontinuous growth parallel to the surface before secondary growth of interior grains is possible. An earlier study of recrystallization textures in 90 pct cold-rolled electrolytic iron showed that secondary recrystallization occurred after annealing for several days at 700C1 This type of secondary recrystallization, which had not been reported previously, results in the formation of a strong texture, best described by the indices "near {554}(225)". The purpose of the present work was to investigate the effect of various processing variables on secondary recrystallization in this material and determine the mechanism of secondary grain growth. LITERATURE REVIEW An understanding of the mechanism of a secondary recrystallization process depends on knowing: 1) how grains in the secondary orientation come to be in the primary recrystallization texture; 2) why normal grain growth does not occur; and 3) what factors determine the strength of the secondary texture. For secondary growth of grains of a particular orientation, a certain minimum fraction of the grains must be in that orientation after primary recrystallization. This requirement is apparently satisfied "naturally" in certain systems, i.e., when the primary texture obtained by rolling and recrystallizing material initially randomly oriented contains a sufficient fraction of primaries in the secondary orientation. However, in other cases, e.g., {110}<001> and {100}<001> secondary growth in silicon iron,2 it is necessary to enhance the fraction of primary grains in the secondary orientation by rolling and recrystallizing textured material. In the present case, the "near {554}<225>" orientation is contained within the spread of orientations found in the primary recrystallization texture of iron or bbc iron-base alloys. In systems where the main driving force for secondary growth is the reduction in total grain boundary energy, secondary growth is observed only when normal grain growth is minimized. Four ways in which normal grain growth can be limited are: 1) Limitation by a strong primary texture. When a very strong primary texture consisting of a single component or twin-related components develop, most primary grains are separated from one another by relatively immobile small-angle grain boundaries. The classic instance of this is secondary growth into the primary cube texture in some fcc metals. 2) Limitation by precipitates. Precipitates present in the proper volume fraction with a suitable dispersion will limit primary grain growth. The role of MnS inclusions in impeding normal grain growth in Si-Fe is well-documented.5 3) Limitation by sheet thickness. Normal grain growth slows drastically when the mean grain diameter is of the same order as the sheet thickness. This effect has been used to obtain secondary recrystallization in thin sheets of high-purity silicon iron.&apos; 4) Limitation by solute impurities. It is well-established that certain impurity elements in solution can have a large effect on grain boundary mobility.&apos; However, there does not seem to be any secondary recrystallization process in which primary grain size stabilization has been shown to be due to the drag exerted on grain boundaries by dissolved impurities. In certain systems, e.g., secondary recrystallization in silver,&apos; the means by which normal grain growth is limited has not been identified, and solute-impurity limitation might be suspected. In order to understand the factors which determine secondary texture strength in three-dimensional growth, it is necessary to examine in more detail the current picture of general secondary recrystallization processes. Following Cahn,9 it is assumed that the primary grains have a range of sizes and that secondary growth of one of the large grains in this distribution is possible when it exceeds a critical size with respect to its neighboring grains. The critical size depends on the ratio ?S/?p, where ?s is some sort of average grain boundary energy between the potential secondary and the primary grains and ?p is some sort of average grain boundary energy between primary grains. For a constant primary grain size, the critical size for secondary growth increases as ?$/?p increases. May and Turnbull5 have incorporated the

Jan 1, 1969

By D. A. Elgillani, M. C. Fuerstenau, M. C. Kuhn

The species responsible for flotation when xanthate is added as collector for pyrite is dixanthogen. Measured oxidation potentials of these systems show that xanthate should be oxidized to dixanthogen, and the presence of dixanthogen on the pyrite surface is confirmed by infrared absorption. Zeta potential measurements are presented and related to collector adsorption. In spite of the normal presence of pyrite in most sulfide ore deposits, only a modest amount of study has been devoted to the xanthate-pyrite flotation system in the absence of activators and depressant~.&apos;-~ As a result, little is known about the mechanism of xanthate adsorption on pyrite. From the few studies that have been made, however, a number of significant observations have been forthcoming. For example, the dependence of flotation response on the state of oxidation of the surface was noted in two studies — one conducted by Plante and Sutherland4 and a later one by plaksin.~ In another study, Gaudin and wilkinson3 found that ferric xanthate was not present on a pyrite surface. In a later investigation, however, Gaudin&apos; and his colleagues did extract a small amount of ferric xanthate into benzene when pyrite was ground in an evacuated mill with water, benzene, and xanthate. This quantity was apparently

Jan 1, 1969

By M. B. Bever, A. K. Jena

Equations for the heat effects of additions of mixtures of multicomponent phases to a solution have been derived in terms of the enthalpy interaction coefficients. By these equations and the measured composition dependence of the heat effects on addition of mixtures of Ag-Cd solid solutions and elemental gold to liquid tin-rich solutions, values of the enthalpy in-teraction coefficients in tin-rich solutions at 541°K have been obtained. Analysis of these results in terms of the regular solution theory and the quasichemical theory suggests that near the melting point of the solvent association in the solution becomes important. SEVERAL recent papers have discussed the nature of dilute solutions on the basis of measured enthalpy interaction coefficients. l-3 These coefficients contribute to the understanding of the constitution of solutions and can be used for the evaluation of thermo-dynamic data of multicomponent systems. Their experimental determination, however, is laborious. This communication reports values of the enthalpy interaction coefficients of silver, cadmium, and gold in liquid tin-rich solutions obtained from the measured heat effects of additions of mixtures of Ag-Cd solid solutions and elemental gold to liquid tin-rich solutions. These measurements were made in the course of the determination of the heats of formation of Ag-Cd solid solutions reported in a concurrent publication.4 THE HEAT EFFECT OF AN ADDITION TO A SOLVENT This analysis is concerned with the addition of a mixture of multicomponent phases from the temperature To to a solvent of known composition at temperature T. If Nmixture << Nsolvent, where N designates the gram-atoms involved, the heat effect per g-atom of mixture added can be expressed as (HT - HT )i = difference in heat contents of component element i in the mixture at T and To Q = heat effect on solution of the mixture at temperature T Also1 Q = S Xi [2] where ?Hi ,T,x = relative partial enthalpy per g-atom of i in solution at temperature T and composition of the solution x x = average of the atom fractions of the added material in solution before and after the addition The relative partial enthalpy ?Hi per g-atom of an element i in a dilute solution composed of a solvent 1 and the solutes j = 2, ... m is related to the interaction coefficients by the following equation5 ?Hi - ?Hi-?Hi,x1-1 + S n1ixj+ . . . +S...S...S nrixn2... Xnji...Xnmm+... [3] vhere Xj = atom fraction of solute j in the solution nri = the rth order enthalpy interaction coefficients, which can also be represented by the more general designation5 L(i)n2,n3...nm and nj may have any positive integral value or zero. For identification of various rth order interaction coefficients, nri is written as nn2i2,...nij,...nmm. Eqs. [1], [2], and [3] combine to give the following general equation for the heat effect on addition of a small quantity of a mixture to a large quantity of a dilute solution n = _?ga ?Ha,To + ? Xi(HT - HT o)i a. i + ?xi?Hi,X,i?1 + ??xnjixj + . . . + ???. . .?. . .?xinrix2n2. . . xnji. . . xnmm+ . . . [4] The first term on the right-hand side of this equation is the heat of decomposition at the addition temperature of the phases present in the mixture, the second term is the heat required to raise the temperature of

Jan 1, 1970

?AARONSON, ALFRED E, .Vice-Pres, Mid-Co Petroleum Co , Mid-Co Bldg, Tulsa, Okla &apos;18 ABADIE, EMILE R, Min Engr - Box 927, Porterville, Cal &apos;76 ||ABADILLA, QuiRiCo A, Student, Colorado School of Mines, Golden, Colo. &apos;20 ABBOTT, CLARENCE E, Gen&apos;l Supt, Iron Mines Div, Tenn Coal, Iron & R R Co , 1405 Minnesota Ave, Bessemer, Ala. &apos;04 ABBOTT, Louis BENJAMIN, Chief Engr, Consolidation Coal Co-, Elkhorn Div, Jenkins, Ky &apos;15 ABBOTT, ROBERT R Met. Engr, Peerless Motor Car Co, Cleveland, Ohio. &apos;12 ABE, ASAKA Fujita Min Co, Dojima, Osaka, Japan &apos;14 ABEEL, GEORGE H, JR, Cons Min Engr, 633 St Paul Ave, Los Angeles, Cal &apos;18 ABEL, ALBERT E, Mgr., Pittsburgh Dist, Valley Mould & Iron Corpn, 28th St & R R Ave, Pittsburgh, Pa &apos;19 ABEL, W D, Min. Engr. 3897 Sacramento St , San Francisco, Cal. &apos;19 ABELL, 0 J, Pres & Treas, Abell-Howe Co, 332 South Michigan Ave, Chicago, Ill &apos;19 ABERNATHY, G E Willow Springs, Mo &apos;20 ABEY, HIROSHI, Min & Met Engr, Arakawa Mine, Mitsubishi Co, Senpoku-gun, Akitaken, Japan &apos;17

Jan 1, 1923

By R. W. Carpenter, J. C. Ogle

It is possible, by using pack-rolling instead of conventional rolling, to reduce a number of metals to thicknesses of 2µm or less. Such thinfoils are generally made at room temperature without intermediate annealing. In addition, pack-rolled foils fail by developing pinholes at thicknesses near 2µm instead of developing the shear cracks usually observed in cold-rolled ductile metals. This paper presents the results of a general investigation of the deformation substructure and texture developed in copper and iron pack -rolled from 130 to about 2µm thickness. Electron microscopy showed that in both metals a fine (0.2 to 0.5?µ m) deformation subgrain structure formed during pack-rolling; in neither case was this substructure grossly different from substructures formed during conventional rolling. The deformation texture formed in pack-rolled iron was quite similar to usual bcc textures; however, in the case of copper, the cube texture was stable during pack-rolling and the normal copper deformation texture was unstable. It is shown analytically that the constraining pack induced a large hydrostatic pressure in the foils during pack-rolling. The pinhole failure mechanism is attributed to the presence of the large hydrostatic pressure during pack-rolling; this strongly suppressed the growth of shear cracks. The stability of the cube texture in copper is also probably due to the unusuul stress distribution developed during pack-rolling. EXPERIMENTS at several laboratories have shown that very thin foils of the common structural metals and many of the rare earths can be made by "pack-rolling". 1-3 The technique was originally developed to make specimens for nuclear scattering experiments and foils for X-ray filters. It is also useful for making experimental laminar metallic composite bodies and foils thin enough for direct examination by ultra-high voltage electron microscopy without the need for special thinning techniques. Pack-rolling in the present context means a three-layer pack, with the material to be rolled into foil comprising the center layer. The outer two layers, which constrain the foil during reduction, are ordinarily austenitic stainless steel. Typically, a 130 µm (0.005 in.) metal strip can be reduced to a final thickness of 2 µm or less by this process. This is accomplished at room temperature, without intermediate annealing. It has been observed that foils produced by this process do not exhibit at any stage of their reduction the severe work-hardening found in strip rolled by conventional cold-rolling methods. Neither is the failure characteristic the same."&apos; Conventionally cold-rolled ductile metal strip fails by developing shear cracks on planes whose normals nearly bisect the angle between the rolling direction and normal to the rolling plane; these are planes of maximum shear stress. In pack-rolling this mechanism has not been observed; failure occurs by the formation of pinholes on the foil surface (penetrating the foil). If pack-rolling is continued the hole density increases. These differences in behavior imply the existence of appreciably different substructure in pack-rolled foils compared to substructure in conventionally rolled material, or perhaps that the geometry of pack-rolling has an effect on the foil behavior. This paper describes an investigation of deformation substructure and texture in some specimens of pack-rolled copper and iron, and some considerations of the stress distribution in the foils during rolling that result from the geometry of pack-rolling. EXPERIMENTAL DETAILS Three different materials were used for pack-rolling in the present work: soft copper sheet (99.8 pct Cu, 0.03 pct 0, electrolytic tough pitch) and two types of iron, Ferrovac E* and Armco iron. Each was "Crucible Stccl Co. initially in the form of 130 µm annealed strip with grain size ranges of approximately 10 to 40 µm. The initial texture of the copper (determined as noted below) was the normally observed cube type (001)[100]; there was evidence of a small amount of material in the cube-twin orientation reported by Beck and Hu.4 The initial texture of the Ferrovac E was similar to that reported for recrystallized iron by Kurdjumov and sachs,5 who list the principal orientations as {111}<112>, {001}<110> 15degfrom RD and a weak component {112}(110) 15 deg from RD. The starting texture of the Armco iron was not determined. Pack-Rolling Procedure. A four-high mill was used for all specimens. The work roll and backing roll diameters were 1.625 and 5.25 in., respectively. The peripheral roll speed of the work rolls was about 2.5 in. per sec. All foils were initially reduced from 130 to 100 µm by conventional straight rolling and then inserted into a pack, without any intermediate annealing, for further reduction. The pack consisted of an 0.033 in. (838 µm) thick 3 by 6 in. polished sheet of austenitic stainless steel, folded to make a 3 by 3 in. jacket. After folding, the jacket was given a small reduction to close the fold tightly before insertion of the foil. During pack-rolling a constant change in roll spacing was made every third pass. The roll-spacing change corresponded to a 5 pct reduction in thickness for a new pack. This approached a 10 pct reduction when the pack had decreased to about half its original thickness. At this point the deformed pack was discarded and a new one

Jan 1, 1970

By Albert R. Ledoux

Discussion of the Paper of Albert R. Ledoux, read at the Atlantic City Meeting, February, 1904. ARTHUR JARMAN, Sydney, New South Wales, Australia&apos; (communication to the Secretary*): Some remarks upon. Dr. Ledoux&apos;s interesting paper from one who has not visited America may, I hope, be of interest to members. It appears to me that there is considerable difference between the training of the American and of the British mining engineer. Not that the subjects are different, but rather in the way in which they are handled, the illustrations being, as far as possible, mining in character. Colloquial instruction is unknown in English curricula, but could be introduced with advantage. Students here assure me that an hour of conversation is of tar more use to them than an hour of the best lecturing. In England a school-year of 6 or 7 months would be considered very short indeed; but Americans do not consider it so, for the reason that the rest of the year is mostly spent in acquiring practical acquaintance with their subjects in works or in the field, and the shorter courses, when coupled with this large amount of outside expe¬rience, produce an essentially practical-minded engineer, who is also more of a business man; whereas the English system, though excellent from a scholastic point of view, produces the theoretical rather than the practical man. British schools are waking up, however, and the practical aspect of the engineer&apos;s training is receiving greater consideration. Once launched upon his career, the American engineer is immediately called upon to exercise his self-reliance and ingenuity, if he is to retain the confidence of his employers; but what can we say of English directors? In how many cases is the engineer allowed to guide the destinies of his company? Witness several recent cases of gross waste of money upon unsuitable plants, and the perpetuation of prehistoric methods of

Mar 1, 1905

Jan 1, 1970

By J. E. Johnson

Discussion of the paper of Mark A. Amnion, presented at the Cleveland meeting October, 1913, and printed in Bulletin No. 70, October, 1913, pp. 1167 to 1 79. J. E. JOHNSON, JR., Ashland, Wis.:-Mr. Amnion&apos;s paper is of great value and it is not with any desire to reflect. on it that I wish to make some comments on the use of the scleroscope. We obtained one on trial some months ago and made very extensive tests with it, but without getting very satisfactory results. The readings on good car-wheels and bad ones were just about the same, but the factor in its use most likely to produce erroneous results is a variation in the thickness of the specimen being tested. In order to find out something on this subject we cut a thin disk, about -1,: in. thick, off a brass rod; then one 0.25 in. thick, and another about 1 in. thick, put the surfaces of all in about the same condition and tested them with the scleroscope. The readings varied widely; the resilience of the anvil evidently entered to a very high degree on thin pieces. By putting a soft cushion between such a thin specimen and the anvil, and forcing it up against the tube, the softness of the cushion cut off the resilience of the anvil and the results were more like those of the thick specimens. After a thickness of 1 in. was passed, the specimen seemed to have mass enough so that the resilience of the anvil no longer played an important part, and above that thickness results on different materials would be comparable, even though the thicknesses differed. But in order to get comparable results on thin specimens the thickness of those being tested should be the same. I should like to ask how the variations introduced in this way were overcome, so as to get strictly comparable results. Mr. AMMON :-.I have not had much experience in that, but the scleroscope is simply an indication of the surface harden-

Dec 1, 1912