Search Documents

By Roland D. Parks

Corundum, little publicized as an industrial abrasive, has, in its small way, contributed greatly to the production of many specialized items vital to our war program and to Our allies. Optical elements Of the highest quality for range finders, bombsights, and scientific instruments; precision metal parts for torpedoes and airplane engines; quartz crystal plates for military radios; armorplate and malleable castings for tanks and guns; and eyeglasses for everyone; these are some Of the products that corundum has helped to produce in the quantities needed and on time. Unlike metals and many other raw materials, corundum is not incorporated into any Of these finished products. It is simply a grinding medium used to produce the desired finish or precision; an operating supply or tool, so to speak. With a Mobs' scale index of 9, corundum ranks next to the diamond in hardness among the natural minerals and is superior to emery and garnet. The gem varieties of corundum, including the Oriental ruby and sapphire, are frequently more highly prized as jewels than the diamond. It is the intent Of this paper to deal Only with a description of the corundum industry, the administration of wartime control, and certain economic aspects as seen by the author. Several references are listed to assist anyone who wishes further information on the geological occurrence of the mineral. Ore Production and Consumption For the past two decades, south Africa has been the world's sole producer of corundum ore. A possible exception is Russia, where, it is understood, there was considerable production during the thirties for domestic consumption but for which statistics are lacking. The United States is the world's principal consumer of corundum ore; imports lor the period 1934 through 1940 averaging 3000 Short tons per year, The years 1935 and 1936 were close to the 5000-ton mark, and imports during 1941, the last prewar year for which statistics have been released, were approximately 6000 Short tons. Again lacking statistics on Russia, the United Kingdom ranks second, but far below the United States in consumption of ore. Historically, corundum has been found in some 35 countries throughout the world, but the principal deposits are in South Africa, Canada, Madagascar, Russia and the united States. Deposits are generally small and subject to rapid exhaustion. Thus, the United States was the principal world producer for the period 1870 to 1900, when operations ceased except for two years during World War I. India was a producer of ore from 1898 through 1921, with peak output in 1916 through 1918 Canada came into production in 1901 with substantial output of ore and finished grain until 1914; the production thereafter was smaller until 1921. Madagascar has produced ore since 1910 but has had important output in only a few scattered years. South African production started in 1912

Jan 1, 1948

By T. L. Joseph

IT is a distinct privilege to participate in this meeting convened to honor the memory of Henry Marion Howe, a distinguished scientist and metallurgist. Many have added to our rapidly growing fund of metallurgical knowledge but few have made the unique contribution of formulating basic concepts essential to an over-all comprehensive view of the subject of metallography. Of those previously selected to deliver this lecture, several have added a personal touch to their discourse because they were able to refer to their associations with Dr. Howe. It was not my good fortune to know him or to enjoy his inspiring influence. Like most of you, my contact has been with his published works, which are outstanding in that they provide lucid, detailed expositions of the nature and behavior of metals and alloys. His deep understanding and clarity of expression have greatly accelerated our progress in metallography and in the use of metals. The degree to which a man's thinking, experimentation and writing contribute toward an understanding of basic laws and phenomena determines whether his life's work is of transitory or permanent value. This occasion appropriately recognizes the fundamental importance of Dr. Howe's pioneer work in the field of metallurgy. On two former occasions, gray iron was selected as a subject for discussion. The fact that the production of pig iron has not been discussed before does not reflect any lack of interest on the part of Dr. Howe or former lecturers in the process that under- lies the production of steel. Although Dr. Howe's work in his later years centered around metallography, his earlier publications show a considerable interest in the production of iron and steel. He recognized that in the ascending spiral of metallurgical advancement we are not winding a single thread but are weaving a complex fabric. Specific evidence of his interest in the production of pig iron may be found in his book1 on The Metallography of Cast Iron and Steel. In explaining why blast furnaces have been in constant use for about 600 years, he says: "The process is economical because it utilizes with extraordinary completeness the calorific power of the coke due to the thorough transfer of heat from the gaseous products of combustion to the charge." This emphasis on heat transfer, overlooked in many more extended and more recent discussions of the blast-furnace process, illustrates Professor Howe's ability to see the essentials. Other distinct advantages of the blast furnace, such as the removal of much of the sulphur and practically all of the oxygen, were mentioned. It was also stated that although the blast- furnace process is complex in nature, its outward form is comparatively simple, thus permitting large-scale production at small labor costs. All who contemplate the production of metallic iron from its ores by any other process might well consider the

Jan 1, 1946

By A. M. Gaudin

A great number of hypotheses has been advanced to explain the complex phenomena that are encountered in flotation. In the days of bulk-oil flotation, when a large quantity of oil was employed, it was observed that the oil-mineral aggregate floated above the ore-pulp because of its lesser density. With the advent of froth-flotation this phase of the theory had to be modified to take into account the presence of air bubbles. The reason why the mineral-bearing froth of today rises to the top of flotation cells is, of course, because the air-mineral aggregate, with whatever reagent may be associated with it, is lighter than the pulp. In an attempt to explain froth-flotation the fact has been emphasized that certain minerals are wetted and therefore remain in water; while others are not wetted and therefore become associated in preference with air. Such an "explanation" does not explain facts, it merely states them; for instance, it does not explain why minerals are wetted under some circumstances and not wetted under others. Going somewhat further, the wetting or nonwetting of minerals by water has been ascribed' to differences in the angles of contact between oil droplets and mineral surface at the surface of the minerals. This explanation, however, was abandoned when soluble flotation reagents came to replace the so-called "insoluble" reagents. Another theory, sponsored about 10 years ago by Ralston,² involves the effects of electric charges at the surface of the mineral particles and air bubbles. This theory, unfortunately, was not developed as fully as it seems desirable. The belief that adsorption phenomena might play a preponderant role in flotation3 has been rather widespread for the last 10 years. Unfor-

Jan 1, 1928

By Henry S. Rawdon

The structure of wrought iron as usually described by metallographists and workers in metal in general is that of a fairly pure iron. Impurities, if present, are usually considered as being in solid solution in the crystals of the ferrite matrix or as forming part of the ever present "slag streaks." Attention is herein directed to one type of these dissolved impurities; to the detection of such impurities, particularly in low-grade irons, and to their possible influence on the physical properties of the metal. The attention of the Bureau of Standards was first directed to wrought iron of the peculiar and unusual characteristics to be described later, in material which had failed in service and was submitted for test. The examination was extended to other grades of wrought iron, to see whether such features are of common occurrence in this class of material. MICROSTRUCTURE OF WROUGHT IRON Usual Structure The general microstructure of wrought iron is so well known that a detailed description of it here is needless. There is shown in Fig. 2 the structure of a sample of Swedish iron which illustrates well the matrix of ferrite crystals in which are embedded the slag threads so characteristic of the puddling process and the subsequent working of the material. The usual commercial product contains varying amounts of the impurities commonly associated with iron and steel, i,e,, manganese, phosphorus, silicon, and sulphur together with small amounts of carbon. Of these, the larger part of the phosphorus and some of the silicon present are held in solid solution in the ferrite while most of the remaining impurities, other than carbon, exist in the in closures of slag. Aside from the discontinuities introduced by the slag streaks the ferrite matrix has the microstructure and appearance of a pure metal. No definite orientation of the various crystals or grains is apparent; deep etching of the specimens reveals no intracrystalline features (i.e., within the grains) other than those noted in " pure " metals in general (etching pits).

Jan 1, 1918

By John D. Roach

DURING an investigation of the yttrium-hydrogen system aimed at producing solid yttrium hydride specimens containing various amounts of hydrogen, it was observed that yttrium containing approximately 2 wt pct H exhibited a tendency to crack and crumble to a powder on standing in air at room temperature. It was also observed that longer hydriding times, at a given temperature, increased this susceptibility to powdering without an increase in hydrogen content, also that moisture in the air is necessary for the observed effects to occur. Even if cracking did not occur, there was a continual formation of a light gray powder on the as-treated surface of the hydrided yttrium and this reaction continues until the entire hydrided piece has been reduced to a powder. Storing the hydrided specimens in the absence of air or removing the surface either by machining or grinding were effective means of preventing this disintegration of hydrided yttrium. In an attempt to determine the reason for this powdering phenomenon, the surfaces of a number of as-hydrided yttrium specimens were examined by X-ray techniques. In all cases the X-ray pattern obtained showed the major phase to be yttrium hydride (YH2) as would be expected since the specimens contained 2 to 2.2 wt pct H. In some cases a trace of yttrium oxide was observed. There was also a third phase present on the surface of these hydrided specimens which could not immediately be identified. This unknown phase was a face-centered cubic material, NaC1-type structure, with a lattice parameter of 4.855 and a calculated density of 5.914 g per cc. Very slight hand polishing of the surface of the hydrided yttrium specimens completely removed both the unknown phase and the traces of oxide so that only the yttrium hydride pattern remained. Based on the X-ray patterns the quantity of the unknown phase on the surface of the hydrided yttrium appeared to be directly related to the susceptibility of the material to powdering. Work at the Denver Research Institute on the yttrium-nitrogen binary system showed that yttrium nitride (YN) is a face-centered cubic material with a lattice parameter of 4.878A and a density of 5.890 g per cc. They also noted that this compound rapidly disintegrated to a powder on standing in air. The unknown pattern observed in the above specimens corresponds very closely to that of the nitride—fcc structure, 4.885 parameter, and density of 5.914 g per cc. The presence of this thin film of nitride on the surface of the hydrided specimens probably accounts for the observed powder formation and crumbling. The nitride reacts with the water vapor in the air (verified by private communication from Dr. C. Huffine, General Electric Co.) to yield yttrium oxide and ammonia. Ammonia is readily detected when hydrided yttrium specimens were allowed to stand in bottled moist air. The powder formed on the surface of the hydrided specimens was shown by X-ray analysis to be yttrium oxide. This reaction appears to occur primarily at the grain boundaries since discrete particles of yttrium hydride separate from the specimens during this powdering process. The reaction of yttrium nitride with water vapor is believed to be as follows: 2YN + 3H2O - Y203 + 2NH3. Despite the fact that this nitride is present only as an extremely thin surface film, if the above reaction is not prevented by removing this film from the surface either by machining or grinding, the reaction continues until the entire hydrided piece has been reduced to a powder. To account for this continuation of the reaction, it is believed that the following reactionalsooccurs: 2YH2 + 2NH3 -2YN + 5H2. The nitride produced by the latter reaction reacts in turn with water vapor. The reaction therefore becomes autocatalytic and continues until the hydride has been consumed and the entire piece reduced to oxide powder. The amount of nitride required to initiate this reaction is quite small and this nitrogen contamination can occur from a number of sources—hydrogen gas employed, minute leak in the hydriding apparatus or even from degassing of the reaction vessel itself. Longer hydriding times increase the possibility of nitrogen contamination and this is especially true when a dynamic gas system is employed in the hydriding process. The production of stable, solid hydrided yttrium is dependent on the complete absence of nitrogen contamination during processing. If such contamination does occur, powdering of the hydrided product can be prevented by removing the nitride from the surface e.g. grinding or by preventing access of air to the pieces e.g. sealing in wax or plastic. The author wishes to express his appreciation to General Electric Co. for sponsoring this research and for permission to publish the results of work under Subcontract AT-93.

Jan 1, 1962

By L.W. Eastwood, Arthur E. Bousu, C. T. Eddy

The recrystallization and grain-growth phenomena of cold-worked metals have considerable industrial importance because of their role in the fabrication of metals. For this reason, and because of the general academic interest in the subject, these processes have received considerable attention since the time of J. E. Stead's paper1 on The Crystalline Structure of Iron and Steel. There are considerable differences of opinion regarding the theory of recrystallization and grain growth and also differences in the observation of the modus operandi of the processes themselves. The value of many of the existing quantitative data on grain growth is decreased by the failure to distinguish between the grain sizes just after complete recrystallization and those resulting from coalescence. For this reason also, the value of the diagrams of stable grain sizes, like those produced by Bass and Glocker2 and Czochralski3, is lessened in so far as an interpretation of the facts of recrystallization is concerned. It is hoped that the data presentcd in this paper will help to clarify and to simplify the facts relating to recrystallization, and at the same time will show that some of the present-day conceptions are untenable. A paper on the theory of recrystallization, with additional data, will be completed in the near future by the writers. Since the literature on the subject has been adequately and frequently reviewed, the only referenccs to it in this paper will be those necessary in the discussion of the data presented.

Jan 1, 1935

By Arthur E. Bousu, C. T. Eddy, L. W. Eastwood

The recrystallization and grain-growth phenomena of cold-worked metals have considerable industrial importance because of their role in the fabrication of metals. For this reason, and because of the general academic interest in the subject, these processes have received considerable attention since the time of J. E. Stead's paper1 on The Crystalline Structure of Iron and Steel. There are considerable differences of opinion regarding the theory of recrystallization and grain growth and also differences in the observation of the modus operandi of the processes themselves. The value of many of the existing quantitative data on grain growth is decreased by the failure to distinguish between the grain sizes just after complete recrystallization and those resulting from coalescence. For this reason also, the value of the diagrams of stable grain sizes, like those produced by Bass and Glocker2 and Czochralski3, is lessened in so far as an interpretation of the facts of recrystallization is concerned. It is hoped that the data presentcd in this paper will help to clarify and to simplify the facts relating to recrystallization, and at the same time will show that some of the present-day conceptions are untenable. A paper on the theory of recrystallization, with additional data, will be completed in the near future by the writers. Since the literature on the subject has been adequately and frequently reviewed, the only referenccs to it in this paper will be those necessary in the discussion of the data presented.

Jan 1, 1935

"Mining as an industry of Utah had its inception in the activities of United States soldiers who came to the Salt Lake valley under the command of Gen. P. E. Connor, founder of Fort Douglas, in October, 1862. Many of these soldiers were from California and naturally employed their spare time in the search for minerals. Although their military status did not permit them to make locations in their own names, they assiduously prospected the region in accordance with their own knowledge and with information conveyed to them by Indians and others. Their efforts were encouraged by their commander, who thereby fairly earned the title of father of the industry here, and by their other officers, and many discoveries that subsequently proved of great value were made by the soldiers.No systematic prospecting or mining had been done in the Territory previously, although early Mormon settlers in the southern portion had mined a little ore from time to time in order to provide supplies of lead for bullets. The Mormon leaders at that time did not encourage mining. They held that agriculture was more important and profitable for their followers.Coal was discovered and produced in 1850. Iron was discovered in 1850 and the first iron plant was in operation in 1852 in Iron County. The first non-ferrous metal production was in 1854, in Beaver County, when Isaac Grundy treated ore from the Rollins mine in what is said to have been the first lead furnace west of the Rocky Mountains. The first mineral location was the West Jordan claim in Bingham canyon, located September 17, 1863, now owned by the United States Smelting, Refining & Mining Co., and still productive. The first district organized in the state was the West Mountain (Bingham), December I 7, 1863. Other important districts of early organization are: Little Cottonwood, December 20, 1869; Big Cottonwood, July 11, 1870; American Fork, July 21, 1870; Uintah (Park City), July 8, 1871; Tintic, December 13, 1896; Ophir, August 6, 1870. The first silver-lead smelting was by J. W. Gibson at Stockton in 1866. Lieut. James Finnerty had previously erected two small trial furnaces there, but made no quantity production."

Jan 1, 1925

By M. A. Scheil

Austenitic stainless alloys are susceptible to stress-corrosion cracking which may occur under certain corrosion environments irrespective of their susceptibility to intergranular corrosion. Test samples are described for investigating stress-corrosion susceptibility of alloys for industrial equipment. A laboratory test using a solution of magnesium chloride boiling at 309 F. was found to produce transgranular cracks in several alloys investigated and in types 347 and 316 stainless steel tubing a residual stress of the order of 10,000 psi. was observed to initiate cracking. The susceptibility to stress-corrosion cracking as judged by the boiling magnesium chloride test indicates that alloys may be selected which will withstand a high stress in service Stressed specimens of stainless alloys included in a corrosion testing program will aid in determining the acceptibility of these fabricated alloys, when stressed, to the service conditions.

Jan 1, 1945

By C. S. Barrett

THE crystal imperfections known as faults in stacking (stacking disorder) are of importance to both fundamental and applied science and are receiving increasing attention. On the theoretical side there have been recent advances in the analysis of diffraction patterns in terms of stacking faults, and on the experimental side it has been found that certain metals develop a faulted structure on cooling through a phase transformation. Beyond this, little is known of what may be called the physical and mechanical metallurgy of faulting, although there has been no lack of discussion and conjecture as to the presence of faults in metals and the effect of faults on mechanical properties and microstructures. In the close-packed metals the nature of faults can be described very simply. Face-centered cubic (FCC) crystals consist of close-packed layers of atoms, (111) planes, stacked above each other in a definite manner. If one layer is designated as the A layer, the next must be a B or a C layer; that is, every atom of the second layer lies not above the atoms of the A layer, but nestles in the hollows between these, using the hollows designated as the B positions, or the equivalent hollows designated as C. If the sequence of layers is ABCABC...., so that layers three spacings apart are directly over each other, the crystal is FCC; if CBACBA ... it is an FCC crystal that is a twin of the former; if ABAB........or BCBC..it is hexagonal close-packed (HCP). A fault is a break in the sequence, such as ABCABABC .. . which has the effect of inserting an HCP lamella into an FCC crystal. Regularly spaced faults spaced two layers apart would convert an FCC crystal entirely to HCP, or an HCP to FCC. A fault in an FCC crystal is also equivalent to creating an FCC twin of minimum thickness; in fact, the entire crystal would be converted to its twin if faults were introduced regularly. (In HCP crystals, however, twinning does not occur on the basal plane and a fault on this plane is not identical with a thin twin). Faults are one of the possible causes for annealing twins,' for the strain markings that are brought out by etching deformed metal,'," for the altered X ray reflecting power of metal at slip bands that is revealed in X ray reflection micrographs,' for the extinction of Kikuchi lines in electron diffraction patterns, and for the hardening of latent slip planes.' Since other explanations of these effects are also available," there has been no direct proof of faults from deformation; yet it has appeared likely that they would occur. Faults resulting from phase transformations in metals, however, have been clearly revealed by diffraction in cobalt" and lithium. It is to be expected that the faulting tendency is greatest

Jan 1, 1951

By F. H. Deily, L. W. Ledgerwood, J. E. Eckel

A new method for drilling the earth's formations has undergone extensive laboratory and shallow earth drilling experimentation. This method, pellet impact drilling, uses the energy of a large mass of high velocity steel spheres to break and crush the rock. Pellets are confined to a region close to the hole bottom. Motive fluid for transporting and recycling the pellets is supplied by a modified jet pump. The pellet drilling method has inherent advantages over conventional rotary drilling. First, only a nominal amount of weight need be applied to the hole bottom. Second, only a very small amount of torque is required for bit rotation. Third, means are available for continual replacement of the cutter medium. The experimental laboratory work and analytical procedures necessary for the design of a pellet drill bit are described. In the laboratory program approximately half the effort was devoted to the development of a better understanding of the physical process, and half to the empirical testing of new bit configurations. Factors such as pellet size and velocity, jet pump characteristics and modifications, and power distribution are discussed. The design and construction of a pellet impact bit for drilling a 9 in. hole with 1 1/4 in. steel pellets are described. Drilling performance in representative rocks, hydraulic operating characteristics, and metallurgical problems are discussed. INTRODUCTION This paper discusses an attempt to reduce drilling costs through the development of a drilling method basically different from rotary drilling. Publications on drilling research indicate that the major effort on the part of manufacturers and operators has been confined to research in rotary, or rotary-percussion drilling. This applied drilling research has produced significant gains in drilling rates and bit life, but thus far it has failed to achieve any major decrease in general drilling costs. From recent statistics released by Drilling Contractors, it can be shown that the total cost of drilling an "average" well in 1953 was about 2 1/4 times the corresponding cost in 1935. Analysis of the costs will show that they are not due to inefficient field operations; they are due instead to both an inflated economy and greater "average" well depths. Diligent work by the industry has reduced the backlog of potential economic improvements in rotary drilling to a group of rather marginal prospects. Increasing depths and poorer quality reservoirs at these depths continue to make the drilling cost problem more acute. Hence, the aim of the work reported here was to develop a new drilling method not limited by the inherent characteristics of rotary drilling and thus capable of attaining further significant reductions in drilling costs. The effort devoted to research on this proposed new drilling method was of considerable magnitude and represented .in excess of 37 man-years of research. The affiliates of Standard Oil Co. (N. I.) sponsored this development program which was conducted by the Drilling Methods Section of the Carter Research Laboratory in Tulsa, Okla. The purpose of this paper is to

Jan 1, 1957

By D. Kramer

HASEN1 has published a phase diagram for the zirconium-nickel system. This phase diagram has been redetermined by Hayes, Roberson, and paasche2 in the range 0 to 50 at. pct Ni. Recently, Smith and Guard3 have published a tentative diagram for the

Jan 1, 1960

By T. E. Leontis

The importance of magnesium alloys in the manufacture of aircraft engines has been realized for many years. A concentrated effort has been exerted in the laboratories of the Dow Chemical Co. to develop magnesium-base alloys with improved properties at elevated temperatures whereby greater advantage can be taken of the inherent lightness of these materials. In an earlier publication, attention was called to the superior tensile properties and resistance to creep of cerium-containing magnesium alloys at temperatures up to 700°F. More recently, additional data on magnesium-cerium alloys have been furnished by Murphy and Payne. The present paper deals with the mechanical properties of sand-cast magnesium alloys containing zinc, at temperatures up to 500°F. The study includes binary Mg-Znt alloys containing up to 10 pct zinc and several ternary and some polynary alloys based on the Mg-~Zn,f Mg-jZn, Mg-4.4211, Mg-6Zn, and Mg-roZn binaries. The compositional variation in the tensile properties, hardness, and creep at room and elevated temperatures, and in the electrical conductivity at room temperature has been determined. The results of these tests show that many zinc-containing magnesium alloys exhibit resistance to creep at elevated temperatures significantly higher than that of present commercial magnesium alloys, but lower than that of alloys of the magnesium-cerium type. In addition, they have high tensile properties at room and elevated temperatures and high conductivity. This combination of mechanical properties and conductivity indicates that these alloys should be given serious consideration for commercial applications involving exposure to temperatures higher than those to which present commercial magnesium alloys can be taken safely. Literature The properties of sand-cast magnesium alloys containing zinc as a principal alloying element have not been investigated very extensively, especially at elevated temperatures. The following remarks, which are confined to sand-cast alloys, will serve as a summary of the most important references on this phase of magnesium metallurgy. The first recorded determination of the tensile strength of binary Mg-Zn alloys as a function of zinc content was reported by Aitchison. Similar studies, including the measurement of elongation and hardness, have been performed by Gann and Winston,' Dumas and Rockaert, Haugh-ton and Prytherch,6 and by Spitaler, the last being reported by Beck.' A slight superiority in the tensile strength of chill-cent Mg + 8 es alloy Over the sand-cast alloy was noted by Maybrey.8 That alloys of magnesium containing 5 to 12 pct zinc

Jan 1, 1949

By R. A. Morse, P. M. Bridges, L. E. Wilsey, Howard N. Hall, P. L. Terwilliger

Theoretical and experimental investigations of a constant pressure gravity drainage system are reported. Experimental data are presented to show that recovery to gas breakthrough by gravity drainage is inversely proportional to rate. The gravity drainage reference rate, which is numerically equal to the so-called "maximum theoretical rate of gravity drainage" is shown to have no particular significance from a recovery standpoint. Before this rate can be used as a basis of comparison for recoveries, it is necessary that the relative permeability and capillary pressure characteristics and displacing fluid viscosities be identical for the systems compared. A method is presented by which accurate prediction of the performance of a gravity drainage system can be made. Close agreement between experimental and calculated drainage performance shows that steady state relative permeability and static capillary pressure data can be used to describe fluid displacement behavior. The very wide range of liquid recoveries before gas breakthrough which result from production rate variation alone demonstrates the importance of this factor in planning depletion of a gravity drainage reservoir. Calculated results are presented which show that little additional recovery can be expected from a high pressure gravity drainage system between the times of gas breakthrough and attainment of such high gas/liquid ratios as to make further pressure maintenance impractical. INTRODUCTION It bas been recognized for some time that gravity forces play an important part in the recovery of oil from some types of reservoirs. Field experience has shown that under certain conditions, gravity drainage can result in very high oil recov- eries. Qualitative reasoning has led most engineers to the general conclusions that: (1) Where gravity drainage is important, the reservoir pressure should be maintained by gas injection at the crest of the structure to prevent shrinkage of the oil in place and to keep a low viscosity so the oil can drain at the fastest possible rate. (2) Recovery by gravity drainage is rate sensitive. A survey of the literature indicates that while considerable work has been done on the effects of gravity in oil production problems, no satisfactory method of calculating the performance of gravity drainage reservoirs has been reported.1,2,3,4,5 In the absence of any proven method of calculating reservoir performance, the level at which pressure should be maintained and the rate of production for most efficient operation has been open to debate. The limits and general character of the recovery us rate relationships are apparent from the following: As rates of production approach zero, oil will drain by virtue of its own weight fast enough that the saturation distribution is always approximately the same as the original static capillary distribution. That is, at the gas-oil contact the liquid saturation goes from 100 per cent to a value of perhaps 10 to 30 per cent in a very short distance, so that as production continues. a relatively sharp gas-oil contact moves down-structure, leaving a very low residual oil saturation in the originally oil saturated zone. At very high rates of production, the oil that drains by virtue of its own weight is negligible and recovery will approach that of a horizontal gas drive, leaving a much higher residual oil saturation. At intermediate rates of production. recovery should be between these extreme*. Despite the lack of quantitative methods, tentative agreement had been reached on the question of optimum producing rate. It has been generally concluded that rather sharp decrease in recovery would occur at rates of production above the "maximum rate of gravity drainage" and hence this rate should not be exceeded. The "maximum rate of gravity drainage" is defined as the rate of production from a 100 per cent

Jan 1, 1951

By L. E. Wilsey, R. A. Morse, P. L. Terwilliger, Howard N. Hall, P. M. Bridges

Theoretical and experimental investigations of a constant pressure gravity drainage system are reported. Experimental data are presented to show that recovery to gas breakthrough by gravity drainage is inversely proportional to rate. The gravity drainage reference rate, which is numerically equal to the so-called "maximum theoretical rate of gravity drainage" is shown to have no particular significance from a recovery standpoint. Before this rate can be used as a basis of comparison for recoveries, it is necessary that the relative permeability and capillary pressure characteristics and displacing fluid viscosities be identical for the systems compared. A method is presented by which accurate prediction of the performance of a gravity drainage system can be made. Close agreement between experimental and calculated drainage performance shows that steady state relative permeability and static capillary pressure data can be used to describe fluid displacement behavior. The very wide range of liquid recoveries before gas breakthrough which result from production rate variation alone demonstrates the importance of this factor in planning depletion of a gravity drainage reservoir. Calculated results are presented which show that little additional recovery can be expected from a high pressure gravity drainage system between the times of gas breakthrough and attainment of such high gas/liquid ratios as to make further pressure maintenance impractical. INTRODUCTION It bas been recognized for some time that gravity forces play an important part in the recovery of oil from some types of reservoirs. Field experience has shown that under certain conditions, gravity drainage can result in very high oil recov- eries. Qualitative reasoning has led most engineers to the general conclusions that: (1) Where gravity drainage is important, the reservoir pressure should be maintained by gas injection at the crest of the structure to prevent shrinkage of the oil in place and to keep a low viscosity so the oil can drain at the fastest possible rate. (2) Recovery by gravity drainage is rate sensitive. A survey of the literature indicates that while considerable work has been done on the effects of gravity in oil production problems, no satisfactory method of calculating the performance of gravity drainage reservoirs has been reported.1,2,3,4,5 In the absence of any proven method of calculating reservoir performance, the level at which pressure should be maintained and the rate of production for most efficient operation has been open to debate. The limits and general character of the recovery us rate relationships are apparent from the following: As rates of production approach zero, oil will drain by virtue of its own weight fast enough that the saturation distribution is always approximately the same as the original static capillary distribution. That is, at the gas-oil contact the liquid saturation goes from 100 per cent to a value of perhaps 10 to 30 per cent in a very short distance, so that as production continues. a relatively sharp gas-oil contact moves down-structure, leaving a very low residual oil saturation in the originally oil saturated zone. At very high rates of production, the oil that drains by virtue of its own weight is negligible and recovery will approach that of a horizontal gas drive, leaving a much higher residual oil saturation. At intermediate rates of production. recovery should be between these extreme*. Despite the lack of quantitative methods, tentative agreement had been reached on the question of optimum producing rate. It has been generally concluded that rather sharp decrease in recovery would occur at rates of production above the "maximum rate of gravity drainage" and hence this rate should not be exceeded. The "maximum rate of gravity drainage" is defined as the rate of production from a 100 per cent

Jan 1, 1951

By J. C. Bowling

Factors governing the choice of building types, materials, and the details of construction for mineral processing plants in remote locations with cold climates are discussed. Alternative types of building insulation in common use are described and a comparison is made of their suitability under various conditions.

Jan 1, 1973

Report of the Secretary TO THE BOARD OF DIRECTORS AND THE MEMBERS OF THE AMERICAN INSTI¬TUTE OF MINING AND METALLURGICAL ENGINEERS GENTLEMEN As will be shown by the special reports of the Finance, Membership, Library, Papers and Publications, Increase of Membership, and other standing Committees, together with that of the Treasurer, the year 1927 was one in which the Institute made very satisfactory progress in a number of directions. In total numbers the membership is no larger but in revenue from dues there has been a marked increase. This has been due to the promotion to full membership of Junior Associates of earlier years, to the larger proportion that come in originally as members rather than juniors, and to the keener interest in the work of the Institute reflected in prompter payment of dues. The latter is important, since experience shows that of those who fall behind a large number must ultimately be dropped for non-payment. Conditions in the mining in¬dustries have been healthy though not booming. It has been much easier for members to find employment and meet their financial obligations but there has not been that flow of young men into mining, and hence in part into the Institute, that characterized certain earlier years. Rather the tendency toward centralization and larger industrial units has re¬stricted the number, though not the scope, of opportunities for technical men in the mineral industries. The Institute is constantly receiving resignations from members crowded out of mining into other lines of activity. On the other hand, those who remain in mining and metal¬lurgy have a greatly increased necessity for information and contacts with technology. A few years ago many superintendents and most foremen were non-technical men. Today the reverse rule obtains and shift bosses and men who occupy even lower positions in industrial units are called upon to know and to apply such an amount of technical knowl¬edge that graduate engineers are the rule rather than the exception. The curious situation has obtained that with a much smaller enrollment of students in the schools of mining and metallurgy there has been at times an actual shortage of young engineers for beginners' jobs. The young men retort that the conditions of employment and pay offered in mining are not equal to those in other lines and, while it is undoubtedly true that the young engineer beginning in mining is able to start under conditions markedly better as to pay, living, and responsibility than did the men who are now leaders, they are required to know much more and have usually spent more in time and money to qualify for their jobs. The whole matter is one which warrants much more attention than has been given to it. For the Institute it is important since the young men

Jan 1, 1923

By J. B. Clemmer, P. E. Churchward, C. Rampacek

A cyclic method for processing manganese ores using sodium sulphate as the basic reagent is described. Sodium sulphate is electrolyzed in a diaphragm cell to give an anolyte-containing agentisdescribed.Sodiumsulphuric acid and a catholyte-containing iselectrolyzedincaustic soda, a part of which is carbonated in a cyclic manner to form soda ash. The reduced ore is leached with the anolyte to dissolve the manganese and the impurities are precipitated by addition of catholyte. Manganese in the pregnant todissolvethemanganeseandtheimpuritiessolution is precipitated as synthetic rhodochrosite with a carbonated catholyte, and sodium sulphate is regenerated. Calcining the manganese carbonate gives a high grade product and the carbon dioxide is returned to the carbonation step. The results of laboratory tests using cells equipped with synthetic-fiber diaphragms and permselective membranes, which permit transfer of anions or cations during electrolysis, are described. A METHOD which has been considered for pro-cessing manganese ores under emergency conditions to recover a product suitable for smelting to ferromanganese involves reductive roasting of the ore for leaching with dilute sulphuric acid followed by precipitation of the manganese from the purified pregnant solution with sodium carbonate. Although the process is operable and involves no novel or untried steps, it is noncyclic in regard to reagents. Research seemed warranted to determine if a cyclic process could be developed by electrolyzing the sodium sulphate formed during precipitation of the manganese with soda ash to regenerate sulphuric acid and sodium hydroxide. Reduced ore would be leached with acid anolyte to dissolve the manganese. The iron, alumina, and other dissolved impurities would be precipitated with the caustic catholyte, and the manganese in the purified pregnant solution would be precipitated as artificial rhodochrosite with carbonated catholyte to regenerate simultaneously sodium sulphate for electrolysis. Waste boiler gas and CO, from calcining the manganese precipitate would be recycled for carbonation of the caustic catholyte. There is a surprising lack of data in the technical literature on diaphragm electrolysis of sodium sulphate. One of the more comprehensive papers, by Atwell and Fuwa, describes the problem involved in electrolyzing byproduct sodium sulphate from the viscose process with particular regard to the design and operation of asbestos diaphragm cells. Frisk' also investigated electrolysis of sodium sulphate from viscose-spinning baths to recover caustic soda and sulphuric acid. The objective in these investigations was to produce, by electrolysis and evaporation, a concentrated caustic-soda solution and a sulphuric-acid solution low in sodium sulphate. Because of these requirements, the process was not too attractive despite a favorable yield of caustic and acid with a reasonable power consumption. Because strong acid and base are not required for processing manganese ores and nonelectrolyzed sodium sulphate is not objectionable in either reagent, the present problem was somewhat simpler than that of these investigators. The purpose of this report is to summarize briefly the results of laboratory electrolysis of commercial sodium sulphate in diaphragm cells of different types and the application of the acid and caustic for processing manganese ores in a cyclic manner. Electrolysis in Permeable Diaphragm Cells The principal problem in electrolyzing sodium sulphate in a permeable diaphragm cell is to prevent mixing of the acid and base formed in the anode and cathode compartments. It is not enough to separate the anolyte and catholyte by a single diaphragm. A three-compartment cell in which the sodium-sulphate solution is fed to the center compartment and flows through the permeable diaphragms to the anode and cathode compartments is more efficient electrically. Diaphragms should be porous enough to allow flow of solution to outer compartments but tight enough to prevent gross mixing of the anolyte and catholyte. In addition to being resistant to acid and alkali, the diaphragms should offer minimum resistance to the flow of current. It is also important that the electrolyte contain a high concentration of sodium sulphate to furnish an abundance of sodium and sulphate ions and thereby decrease the current carried by hydrogen and hydroxyl ions. A practical limitation of sodium-sulphate concentration is imposed by the decreased solubility of sodium sulphate with decreasing temperature. At 20°C, a concentration of 200 g per liter sodium sulphate can be maintained. Little is gained in conductivity by using a concentration greater than 200 g per liter. The small-scale continuous electrolysis tests were made in a 12x12 in. open-top bakelite cell equipped

Jan 1, 1956

By K. Huessener

In presenting the following data on combustion in the open hearth furnace and the advisability of automatic combusion control, the author finds himself much more severely handicapped by the lack of reliable test results than he had anticipated when he first undertook to write this paper. In order thoroughly to investigate how the results of an open-hearth furnace are influenced by combustion, one would have to draw up a large number of heat-balance sheets, as Kinney and McDermottl have given for one heat in their extremely able paper on "Open Hearth Efficiency,' presented before the American Iron and Steel Institute on October 27th,1 1922. Instead of covering only one heat, however, such heat-balance sheets would have to embrace a large number of heats, and not only for one kind of fuel, but for all the various fuels in customary use. Use of Radiation-protected Pyrometer Such tests necessitate extremely careful temperature readings, and here the first serious difficulty presents itself. Nearly all the temperature readings so far published have been taken with thermocouples for the lower ranges and with optical or radiation pyrometers for the higher ranges. This method of measuring reveals the temperature of the surrounding walls, or in the case of optical or radiation measurements, the temperature of that part of the opposing walls which has been focused by the instrument. The error in ascertaining the temperature of the gases entering or the waste gases leaving the checker chambers is probably not very large, as the flowing gases impart their temperature to the walls of the flues. On the other hand, the uptakes, where the preheat temperature of gas and air are usually measured, are under the influence of radiated heat from the port ends, and correct temperature readings can here be taken only by using a radiation-protected pyrometer of the aspirating type.

Jan 1, 1926

By Reaves. M. J.

The title of my talk, "What Happened to the Uranium Boom?" is old news. Certainly it is for this group. All of us that make our living in uranium know that the boom of the last half of the 1970's is over. U.S. production has been exceeding consumption by more than two to one. Mines and mills are closing and yellowcake prices have been dropping for over 20 months. The gloomy outlook for the industry in the near term has been well documented by soothsayers of various descriptions, your daily newspapers, and in the Nuexco Monthly Reports. I'd like to attempt to describe the next upturn in the market (speculate, really) based upon the clues we're seeing now. In order to do that, I'd first like to go over briefly, some of the market factors that contributed to the recent price drop and resultant production cutbacks, and then hypothesize on the way these factors are changing and will change. Market prices are greatly affected (maybe even entirely determined) by buyer perceptions. This is particularly true with uranium, because of the long lead times associated with nuclear plant construction and also with conventional mine/mill development. Before the price rise (say, 1975) utility uranium buyers believed that: 1) U.S. producers would have difficulty expanding to meet U.S. demand. 2) Australian and Canadian production was essential to avoid shortages in the early 1980's. 3) Uranlum prices would continue to rise as demand exceeded supply. 4) Enrichment capacity would become inadequate. It was thought necessary, therefore, to build enriched inventory in the early 1980's for use in the late 1980's. Artificially accelerated expansion of the uranium producer industry was necessary to accommodate anticipated enrichment demand. Current perceptions are largely the opposite. These are the beliefs that were held most of this year and late last year as prices dropped. 1) U.S. production is far in excess of domestic need. Contraction of the U.S. production lndustry is necessary. 2) Canadian and Australian supply is optional and not essential. Producers in those countries are expanding mainly by displacing higher cost production and not because they fill a void, 3) Prices may be essentially stable for some time. 4) Enriched uranium is in excess supply. That is 1981. 1982 is shaping up to look like this: 1) Prices will have bottomed out. (That is not Nuexco's opinion necessarily, by the way, but it is my opinion.) 2) There will still be substantial utility inventories, but fewer spot sales. 3) Canadian and perhaps Australian sellers will have made substantial sales in the U.S. and will be aggressively seeking more. 4) U.S. production will have been dramatically curtailed. U.S. utilities that wish to con- tract long term will have difficulty in finding domestic sellers. Concern will develop about the availability of U.S. production capability. Virtually all long term con- tracts signed will be with non-U.S. sellers. 5) An awareness will begin to develop among U.S. buyers that we are approaching a period of dependence upon foreign uranium (which will be true). The history of the uranium market has been one of dramatic changes and overreaction to those changes. The rapid price rise of a few years ago generated excess U.S. production capacity and the rapid price drop of the last two years will almost certainly result in too little capacity. It will soon be difficult for U.S. buyers to buy domestic material except on the spot market. The question is, "will they care?" The lack of demand, of course, is the underlying reason for the current poor health of the uranium industry. In 1972, 1973 and 1974 collectively, there were 105 nuclear reactors ordered in the U.S. That ordering rate was expected to continue and accelerate throughout this century. In 1975, 1976, 1977, 1978, 1979, and 1980 altogether, there were 56 more reactors cancelled than ordered. The net growth of our only customer since 1974 has been a negative 56. TO put this in perspective, if these 56 reactors were operating now it would more than double present U.S. uranium consumption. Underlying lack of demand is something that is simply not going to change in this decade. Time is going to be required. The NRC indicates that the maximum feasible number of new reactors that can be licensed each year is six. That would increase uranium consumption by only 10% per year. New reactors, if ordered tomorrow, would not generate new uranium demand until after 1990. Even so, United States' consumption of uranium will rise from the 1980 level of 18 million pounds per year, to

Jan 1, 1982