Search Documents

By Jun Hino, P. G. Shewmon, P. A. Beck

THE investigations of Crussard,' of Guinier and Tennevin,' and of Dunn and Daniels," indicate that the subgrains formed in a cold worked and annealed metal are capable of growing at each other's expense during annealing, if the temperature of annealing is sufficiently high and the time is long enough. The results of Dunn and Daniels are particularly convincing in showing that subgrain growth is essentially the result of the free surface energy associated with the subboundaries. In subgrain growth, as in ordinary grain growth, energy is gained as a result of the decrease in total subboundary surface area per unit volume. Recently, Wood and Scrutton4 found that the rate of subgrain growth upon annealing increased very considerably, if simultaneously a creep strain was applied to the specimen at a low strain rate. Working with 99.98 pct pure fine-grained aluminum, these investigators found that the continuous X-ray diffraction back-reflection rings of material strained at room temperature remained continuous after heating for ten days at 250 °C. However, when heated at the same temperature under a stress of 1000 psi even for only three days, the formerly continuous X-ray diffraction rings broke up into numerous dots, which were fairly clearly separated from each other. The continuous X-ray diffraction rings were interpreted as indications of a very small subgrain size, not resolved by the X-ray diffraction method used. The breaking up of the continuous X-ray diffraction ring during annealing under stress was taken as an indication of a great increase in subgrain size, so that the individual subgrains could then be resolved. The effect of simultaneous strain at a low strain rate in accelerating subgrain growth, discovered by Wood and Scrutton and designated by them as "cell growth," is of fundamental importance. The experiments described in this note were carried out in order to confirm Wood and Scrutton's results by direct metallographic observation. Also, information was sought as to the minimum creep strain necessary to produce this effect. A fine grained high purity aluminum strip was prepared by alternate 33 pct rolling and annealing treatments for 1 hr at 350°C. Specimens cut from this strip were subjected to a relatively fast creep strain of 7.2 pct in 3.5 min at 300°C under a constant load initially corresponding to 1185 psi. The subgrains set up were large enough (about 0.015 to 0.03 mm) to be clearly observed (Fig. 1) at X200 magnification with polarized light, after electrolytic polishing and anodic etching, producing a fine oxide film." The corresponding X-ray diffraction pattern is shown in Fig. la. After the fast creep strain treatment a portion of the specimen was subjected to a creep strain of 8.3 pct in 44 hr at 350°C under a constant load initially corresponding to 320 psi. Another portion, annealed under the same conditions, but not strained, served as control specimen. The subgrain size of a typical area of the specimen annealed under strain and of the one annealed without strain is shown in Figs. 2 and 3 (X-ray diffraction patterns, Figs. 2a and 3a). Annealing without strain produced clearly observable subgrain growth (subgrain size: about 0.03 to 0.05 mm). The effect of simultaneous strain was to increase greatly the rate of subgrain growth (resulting in a subgrain size of approximately 0.05 to 0.13 mm), in accordance with Wood and Scrutton. In another experiment, the effect of the amount of simultaneous strain was studied. The initial subgrain structure was set up by fast creep, as described previously. The specimen was then heated at 350 °C under a constant load initially corresponding to 320 psi, as above, for 2.2 hr (0.24 pct strain), and 8.8 hr (0.58 pct strain). Comparison with the corresponding unstrained control specimens by means of X-ray diffraction showed that 0.58 pct strain definitely had an effect, but the effect of 0.24 pct strain was doubtful.

Jan 1, 1953

By H. D. B. Wilson

"IntroductionRECENT ADVANCES in geo-chemistry and in •our knowledge •of crystal structure provide a key which enables us to create a systematic picture of the genesis of many ore deposits. This genetic scheme may be used with confidence in assessing certain types of orebodies and may be of some aid in actual exploration, since it affords a rational explanation of the dependence of the composition •of the ore minerals on that of the rock type in which they occur with which they -are •associated. For purposes of the present paper, .the elements chosen are •chromium, vanadium, iron, and titanium. The oxides of all these metals occur in deposits of similar or related type, and it is proposed to show that, for each, the composition of the •ore mineral is related to •the composition of the enclosing :rock, and that one of the principal factors controlling the composition of the ore is the ionic size of its constituent elements.Geochemical PrinciplesThe crystals of the rock-forming silicates and of the magmatic oxide minerals are essentially ionic types. This means that they are composed •of oppositely charged ions such as Mg²+ and 0²-, which are held together by electrostatic attraction. The ions of each element are spherical, with characteristic size known as the ionic radius. Crystals are built up by the packing of these spheres in the most stable arrangement compatible with the size and the size and valence of the ions• involved.Many of the principles governing the formation of ionic crystals are •simple ,and logical."

Jan 1, 1953

By C. R. Hocott

"IntroductionRESEARCH in petroleum production consists primarily in investigations related to the drilling for and recovery of oil. As an organized activity of individual oil companies, production research is now 30 to 35 years old, and the petroleum industry may point with justifiable pride to the achievements of this third of a •century. Emphasis on research has grown through the years until at the present time many of the larger companies operating in the United States •have well-organized production research staffs.In addition to the efforts of the oil companies, significant research and development in petroleum production technology have been performed by oilfield service companies and others. Valuable contributions have been made through fundamental research carried on by the U. S. Bureau of Mines and by various colleges and universities, both in their own programmes and in programmes sponsored by industry, such as those of the American Petroleum Institute. However, the total effort of these groups is small when compared to the sum of the effort devoted to research by the individual .oil companies. In contrast to some industries which conduct the major portion of their research through co-operative, sponsored research at universities or research institutions, research by the petroleum industry is done predominantly by individual company research staffs. These industrial research groups have usually been organized in such a way as to provide liaison and co-ordination with operating technical staffs. In this way, the research groups are kept aware of the major problems confronting the operating departments and, correspondingly, the operating technical people •are able to keep informed on research activity and progress. This type of close contact generally results in prompt testing of research developments in actual operations."

Jan 1, 1953

By R. B. Burt, J. A. Barr, I. S. Tillotson

DISCUSSION Howard Howie (Knoxville, Term.)—The authors are to be congratulated on the presentation of a paper containing so much valuable information on the pipeline transportation of phosphate, as there is very little literature on the subject. The writer is especially interested in the paper, as he conceived the arrangement of the Akin and Godwin plants and was in charge of the design work and the engineering incident to their construction. The Akin and other phosphate deposits in the Tennessee phosphate area lie on beds of limestone that are very irregular. The limestone beds, after the phosphate matrix has been removed, are similar in appearance to land severely eroded by the action of water and denuded of top soil. Depressions in the limestone, called cutters, are irregular in depth with vertical or overhanging walls, having the general appearance of cracks in dried clay. They change abruptly in direction, width, and depth, and vary on the Akin tract from 1 to 25 ft in depth and from 1 to 50 ft in width. Pinnacles of limestone commonly occur in the cutters which appear, when exposed, like small clifflike islands in a river. Limestone floats also occur. The phosphate matrix fills the cutters and covers the uncuttered areas, the thickness of the cover varying continually and sometimes rather abruptly. It occurs generally as stratifications of phosphate rock and clay of varying thickness. The phosphate rock in the matrix varies in hardness and in percents of silica, lime, iron oxides, and fluorine, and the clay varies in toughness. In some places the deposit consists of narrow strata of rock almost devoid of clay streaks. In other nearby locations the clay will predominate. When it is excavated, the phosphate rock breaks into thin irregular lumps, locally known as plate rock. Limestone lumps are also excavated with the matrix. Akin plate rock is generally much softer than that occurring in other deposits in the area. Because of the above described physical and chemical variations of the excavated material, the resultant slurry varies in size distribution, specific gravity, and percent of slimes. When the rock is soft or when there is an increase of clay, the slime fraction is greatly increased as it passes through pumps and pipelines, resulting in reduced pipe friction. It is obvious that the longer the pipeline the greater the reduction of coarse fractions into fines, causing a decrease in pipe friction that cannot be accurately evaluated. The matrix is mined with a dragline that drops it into a hopper with a grid composed of 9-in. parallel bar spacings located above the hammer mill. The matrix on, and passing through the grid, is subject to the action of powerful sprays which wash it down to the hammer mill, together with any limestone lumps that are not removed before passing through the grid. The hammer mill reduces the feed to lumps of plate rock and clay, most of which will pass through the 8-in. pump suction. The mixture discharges into a pool containing the pump suction pipe. Water from a hydraulic nozzle moves the mixture to the pump suction intake. The pump, driven by a variable speed motor, is the same size as the pumps mentioned on p. 279. Provision is made to remove any lumps that lodge in a bend in the suction pipe in a manner similar to that used in the Florida phosphate fields. The hammer mill and pump units are mounted on wide steel skids so that they can be moved as the mining operation progresses. The discharge from the pump flows through an abrasion-resistant spiral welded steel pipe 81/4 in. actual inside diam, 8 in. nominal diam, for a maximum distance of 2200 ft, which is the limiting pumping distance for one pump. This pipeline, referred to hereafter as pipeline A, discharges into a ball mill without balls, which in turn discharges into a rotary screen attached to it that separates the slurried matrix into 11/4-in. oversize and undersize fractions. The oversize is returned to the mill for further reduction; the undersize is pumped to a Dorrco washer and then flows into a hydroseparator 160 ft in diam. In spite of the size reduction in the hammer mill and the blunging and washing of the slurry in its passage through the pump, pipeline, mill, and washer, the discharge to the hydroseparator frequently contains mud balls almost perfectly spherical. Sometimes the discharge from the 16,000-ft pipeline at Godwin contains mud balls the size of bird shot and smaller. This pipeline will be referred to subsequently as line B. Liquid caustic is added to the slurry at the Akin plant before its passage through the hydro-separator, which decreases the size of particles in the overflow by dispersion. In passing through pumps 1, 2, and 3 and pipeline B, the slime fraction in the underflow is increased by abrasion and blunging and also by continuing dispersive action of the caustic. The matrix for use in the experimental tests referred to on p. 279 was obtained from three small surface openings on the Akin tract that were made previous to the purchase of the tract by the Authority. Matrix used in the 2 and 4-in. experimental pipeline tests was taken from the three openings and proportioned to obtain a sufficient quantity that would be fairly representative of the average in the Akin deposits. Prospecting samples of matrix had been obtained from drill holes which showed no small variation in physical and chemical properties. Some of the physical variation is evident from the size distribution of solids in samples taken during the tests covering line B flows so thoroughly made by the Authority und'er the direction of Mr. Burt, see Table V, p. 280. Hydraulic gradients for a pipe of 8-in. diam were derived from the 2 and 4-in. pipeline tests using the so-called representative matrix as above described, and plotted on the profile of pipeline B. Gradients of other materials in slurry form passing through pipelines that bore some similiarity to the Akin matrix slurry were also plotted. After a study had been made of the hydraulic gradients plotted on the profile and the varying slurry flow that would probably occur during actual operation, three pumps were ordered, referred to as No. 1, 2, and 3 on p. 279. No. 1 and 2 pumps were installed and the third kept in reserve should the operation of 1 and 2 pumps prove satisfactory, since installation of the third pump would require an attendant, as well as the laying of 5400 ft of pipe to supply it with seal-water from the Akin plant. Subsequently, it was found desirable to install the third pump to maintain capacity when the slime fraction was low and the coarse fractions were large. Reference to Fig. 6 will show that the flow in B line goes upgrade in three locations. At the outlet at Godwin, the slurry flows between two 45" bends for an approximate distance of 18 ft to rise above the ground a sufficient height to discharge into a launder feeding the first classifier. This condition requires extra energy, which is taken care of by keeping the hydraulic gradient a sufficient distance above the high points. Although there are rather heavy upgrades in the line, the choking condition that might occur at the

Jan 1, 1953

By J. H. Henderson, H. J. Ledbetter, N. B. Gove, J. D. Griffith

INTRODUCTION The results of a series of laboratory flood tests using liquid Iso-butane to displace refined oils from test cores are pre- ented and interpreted on an empirical bask. The study Revealed the similarity of the miscible liquid displacement to that of the immiscible-fluid displacement mechanism. The efficiency of the iso-butane flood decreased markedly as the oil Viscosity increased. but the effect of injection rate on the effectiveness of the primary production stage was negligible over the range investigated. The presence of free-gas saturation prior. to iso-butane breakthrough increased the volume of iso- Butane required to recover a given percentage of the oil present. Injection of liquid i.e.-butane prior to water follicle sculpted in a marked improvement in oil recovery by the water flood. INTRODUCTION The production of petroleum is often enhanced by the injec-1i1)n of extraneous fluids into the reservoir. It has been suggeited that the injection or cycling of a wet gas or a liquefied petroleum gas would he instrumental in increasing the effic.ienr!; of oil recover! to a greater degree than the commonly injected fluids. dry pas and water. Although instances of injection of light liquid hydrocarbons are not unknown, a systrmatic recording of the result is unavailable and superfi- cially, the practice gives the impression of being economicaIIy unsound. For specific types of displacement, analytic: solutions have been advanced which aid in understanding the physical mechanisms involved. However, there is no generalized theoretical concept which permits adequate prediction of displacement efficiency from a knowledge of readily measured reservoir rock and fluid properties. The Buckley-Leverett approach to oil displacement by an immiscible phase is an admirable analysiy of that type of mechanism. Dykstra and Parsons have introduced a useful concept in their evaluation of the role of the mobility ratio and its merit in rationalizing displacement phenomena. Everett, Gooch and Calhoun3 in their report on the effect of viscosity ratio and miscibility have pointed out the lack of a comprehensive theoretical approach and the desirability of investigating the mechanism of miscible-miscible displacement. In lieu of a well-developed theory concerning miscible-111isci1)le displacement and in view of the scarcity of engineering information on actual LPG injection trials, the limited program of laboratory experimentation described below was undertaken. OBJECTIVES The original broad objectives of the program, to study the oil recovery process using LPG as the displacing phase, defined the direction and scope of the laboratory tests. The specific objective. of the experimentation were to evaluate

Jan 1, 1953

By E. W. Filer, L. S. Darker

ONE of the primary purposes of this investigation was to determine how far blast-furnace metal and slag depart from equilibrium, particularly with respect to sulphur distribution. In studying the equilibrium between blast-furnace metal and slag, there are two approaches that can be used. One method is to use synthetic slags, as was done by Hatch and Chipman;' the other is to equilibrate the metal and slag from the blast furnace by remelting in the laboratory. In the set of experiments here reported, metal and slag tapped simultaneously from the same blast furnace were used for all the runs. The experiments were divided into two groups: 1—a time series at each of three different temperatures to determine the t.ime required for metal and slag to equilibrate in various respects under the experimental conditions of remelting, and 2—an addition series to determine the effect of additions to the slag on the equilibrium between the metal and slag. An atmosphere of carbon monoxide was used to simulate blastfurnace conditions. The furnace used for this investigation was a vertically mounted tubular Globar type with two concentric porcelain tubes inside the heating element. The control couple was located between the two porcelain tubes. The carbon monoxide atmosphere was introduced through a mercury seal at the bottom of the inner tube. On top, a glass head (with ground joint) provided access for samples and a long outlet tube prevented air from sucking back into the furnace. The charge used was iron 6 g, slag 5 g for the time series, or iron 9 g, slag 7 % g for the addition series. This slag-to-metal ratio of 0.83 approximates the average for blast-furnace practice, which commonly ranges from about 0.6 to 1.1. A crucible of AUC graphite containing the above charge was suspended by a molybdenum wire in the head and, after flush, was lowered to the center of the furnace as shown in Fig. 1. The cylindrical crucible was 2 in. long x % in. OD. The furnace was held within &3"C of the desired temperature for all the runs. The temperature was checked after the end of each run by flushing the inner tube with air and placing a platinum-platinum-10 pct rhodium thermocouple in the position previously occupied by the crucible; the temperature of the majority of the runs was much closer than the deviation specified above. The couple was checked against a standard couple which had been calibrated at the gold and palladium points, and against a Bureau of Standards couple. The carbon monoxide atmosphere was prepared by passing COz over granular graphite at about 1200°C. It was purified by bubbling through a 30 pct aqueous solution of potassium hydroxide and passing through ascarite and phosphorus pentoxide. The train and connections were all glass except for a few butt joints where rubber tubing was used for flexibility. The rate of gas flow was 25 to 40 cc per min. As atmospheric pressure prevailed in the furnace, the pressure of carbon monoxide was only slightly higher than the partial pressure thereof in the bosh and hearth zones of a blast furnace—by virtue of the elevated total pressure therein. Simultaneous samples of blast-furnace metal and slag were taken for these remelting experiments. The composition of each is given in the first line of Table I. There is considerable uncertainty as to the significant temperature in a blast furnace at which to compare experimental results. This uncertainty arises not only from lack of temperature measurements in the furnace, but also from lack of knowledge of the zone where the slag-metal reactions occur. (Do they occur principally at the slag-metal interface in the crucible, or as the metal is descending through the slag, or even higher as slag and metal are splashing over the coke?) The known temperatures are those of the metal at cast, which averages about 2600°F, and of the cast or flush slag, which is usually about 100°F hotter. To bridge this uncertainty, remelting temperatures were chosen as 1400°, 1500" (2732°F), and 1600°C. For the time series the duration of remelt was 1, 2, 4, 8, 17, or 66 hr; crucible and contents were quenched in brine. The addition series were quenched by rapidly transferring the crucible and contents from the furnace to a close-fitting copper "mold." Of incidental interest here is the fact that the slag wet the crucible

Jan 1, 1953

By R. A. Cattell

The conditions under which the researches of the Bureau of Mines on petroleum and natural gas were conducted in 1952 were little changed from those indicated in the last report,2/ which dealt with activities during 1951, immediately after crossing of the 38th Parallel by the North Korean Army. Although only a small part of the program was classified in the military sense, there was a feeling of the clash of world forces which called for even cheer scrutiny of the research problems so that the emphasis could be placed without delay where the greatest needs for na¬tional defense seemed to be. The reports of the work accomplished were so directed as to have the greatest immediate value to persons charged with supply planning for the military forces and included information on the availability and characteristics of a wide variety of crude oils, fuels, and other petroleum products. Actually, the approach, direction, and conduct of the work do not differ greatly under the two circumstances, as has been pointed out in earlier reports; only the tempo changes.

Jan 1, 1953

By B. L. Averbach, Morris Cohen, L. L. Seigle

Free energies, enthalpies, and entropies of mixing of Ni-Au solid solutions containing 5 to 95 atomic pct Ni have been determined by the electromotive force method at 700° to 900°C. The thermodynamic activities exhibit large positive deviations from Raoult's law, and the entropies of mixing are almost twice those of ideal solutions. The enthalpies of mixing are positive (heat is absorbed) and are attributable to the lattice distortional energy resulting from the size difference between the nickel and gold atoms. This factor appears to be responsible for the miscibility gap at lower temperatures. IN the thermodynamic study of metallic solid solutions, most interest has been directed toward systems with negative deviation from Raoult's law, namely, those exhibiting superlattice or compound formation. The results of previous investigations are summarized in recent publications.'-' Relatively little experimental work has been carried out on solid solutions which manifest a positive deviation, possibly because the range of solubility in such cases is usually quite limited. Nevertheless, the relationship of the thermodynamic properties of these solutions to diffusion, nucleation, and precipitation in the solid state are of considerable importance. The binary Ni-Au alloys are particularly suited to an investigation of these relationships. Despite the presence of a miscibility gap at lower temperatures, Fig. 1, indicating a large positive deviation from Raoult's law, complete solid solubility is found above 840°C. Moreover, the difference in the atomic scattering powers of nickel and gold is sufficiently great to permit X-ray diffraction studies of atomic arrangements and pre-precipitation phenomena. Radioisotopes of both nickel and gold are available for diffusion work, and finally, a large difference in nobility between the two elements facilitates measurement of the thermodynamic properties. The present paper describes the experimental determination of the free energies, enthalpies, and entropies of mixing of solid Ni-Au alloys. Table I gives a list of the symbols used in the paper. Experimental Method The stability of nickel chloride relative to gold chloride" indicated that the galvanic cell method could be used for determining the thermodynamic properties of Ni-Au alloys. An electrolytic cell (Fig. 2) was constructed, similar to that of Weibke and Matthes,7 in which the electrodes were solid nickel and Ni-Au alloys, and the electrolyte was a fused mixture of alkali chlorides containing NiCl,. The cell electrodes were made from fine gold granules and carbonyl nickel shot melted together under argon, chill cast, swaged to 1/16 in. diam rod, and annealed for one week at 850°C. Commercial reagent and chemically pure grade salts, purified by dehydration, were used for the electrolyte. The cell, operating in an atmosphere of purified argon, was heated in a resistance-wound cylindrical furnace whose temperature was controlled to within ±0.5ºC. The potential developed between the pure nickel and the alloy electrodes, which is related to the thermodynamic properties of the alloys by standard equations to be presented later, was measured with a potentiometer and a mirror galvanometer sensitive to 10-7 v. Dehydration of the electrolyte was carried out in the assembled cell by evacuating at 100°C for about

Jan 1, 1953

By R. S. Busk

A PREVIOUS paper1 has summarized the effect of A all metallic elements on the lattice parameters of magnesium. The present paper deals with the effect of temperature on the lattice parameters and the way in which that effect is modified by alloyed elements. The experimental techniques for sample preparation, exposure to the X-ray beam, measurement of line diameters, and calculation of the parameters were the same as reported in the previous paper. The temperature of the specimen was raised by surrounding the mounted compact with a conical Glas-Col,* the base of which was sealed with Saran film. In this way the temperature of the specimen could be raised to 200 °C, which was the maximum desired in the present study. Control of temperature was effected by maintaining a constant, desired voltage to the resistance coils of the Glas-Col through a Variac. Temperature was measured by an iron constantan thermocouple embedded in the body of the specimerl so that the thermocouple bead was within 1/16 in. of the surface exposed to the X-ray beam. Variation of temperature during an exposure was less than + 1/4 oF. A series of eight alloys, consisting of pure Mg, Mg+Ag, Mg+Al, and Mg+Sn were studied. All percentage values are in atomic percent. The results are given in Table I. The density values given in Table I were calculated from the lattice parameters, using an equation due to Foote and Jette:"

Jan 1, 1953

By D. R. Keck

"SINCE the .Canadian Chemical Company has no direct connection with mining operations, and I have had no experience with mining, there is little I can tell you that you do not already know. However, we have had considerable experience with certain types of metallurgical problems and I would like to discuss with you some of these problems and their solutions by our metallurgists.In order to acquaint you with the type of plant and processes to be employed at Edmonton, I would like first to take a few .minutes to trace briefly the history -of the Canadian Chemical Company's affiliate, The Celanese Corporation of America. In the early •part of the twentieth century, two young Swiss brothers, Camille and Henri Dreyfus, received their P.h.D. degrees in chemistry. They were extremely interested in work which was being carried on at that time to find a suitable synthetic fiber that could compete with natural fibers, both quality and price-wise. Early man-made fibers were both coarse and hard to dye. The Doctors Dreyfus• poured all their earnings into research and ultimately developed cellulose acetate filament. During World War I, the Dreyfus brothers were invited to the United States to produce cellulose acetate 'dope' for airplane wing coverings. Dr. Camille Dreyfus built the first American plant for fiber production at Cumberland, Maryland, in 1924.Due to resistance of textile mills to the new fibers, Celanese was forced to set up its own dying, weaving, and finishing mills to prove the new materials. Through the years, however, this operation has •been retained primarily for fabric development purposes,.. with the majority of the acetate being sold to other textile mills."

Jan 1, 1953

Most of the production of germanium in the U. S. is from byproducts of smelting Tri-state zinc ore. Only in England has commercial manufacture been reported from coal.

Jan 1, 1953

By G. R. Heffernan

"IntroductionTHE PURPOSE of this paper is to give a •brief history of iron and steel in British Columbia, a quick look at the present operations of Western Canada Steel, Limited, a review of iron ore resources and iron and steel markets, and a projection of what the future might hold for the industry in British Columbia.From the Past to the PresentWhile the paper is entitled Past, Present, and Future, in covering the past, which we shall call the time prior to 1947, there is very little to be said. Small shipments of iron ore were made from the Texada deposits by the Puget Sound Iron Company from 1886 to 1907. Total ore shipped did not exceed 70,000 tons. Part of this is believed to have been used in building a United States battleship in 1907 in the Bremerton Naval Yards in Seattle, Washington.In 1914 a small steel mill was started on Lulu island, rolling bars from •box piles and used shafting. This mill operated spasmodically for a few years but finally burned down in 1921. The rolling mill stands were sold to China and are no doubt in operation in China today.In 1916 the City of Port Moody assisted in the financing of a mill which operated on re-roll rails, box piles, and steel ingots made in an experimental electric furnace in Port Moody. This furnace also produced small quantities of pig iron scrap. The backers of the Port Moody mill showed a great deal of enterprise and must have been a very forward looking group, since this was one of the first recorded applications of the electric furnace to small ingot production. Despite their enterprise, the operation was unsuccessful and terminated in 1921."

Jan 1, 1953

By W. C. Leslie, R. M. Fisher, K. G. Carroll

A nitride, believed to be Si3N, has been separated from three nitrided silicon steels. Germanium nitride, Ge3N4, has been prepared from pure germanium. Comparison of the diffraction patterns indicates that the two nitrides are isomorphous; on orthorhombic structure is suggested in place of the rhombohedral structure previously reported for Ge3N4. THE possibility that a nitride of silicon may, under appropriate conditions, precipitate in silicon steels or in steels killed with silicon makes it desirable to have some positive means of identifying such a compound. One such means is the X-ray or electron diffraction pattern of the nitride. A review of the meager data in the literature indicates that the nitride most likely to form is Si3N4, a conclusion supported by the results of a study of nitrided silicon steels to be published shortly by L. S. Darken and R. P. Smith, of this Laboratory. Unfortunately, there is available no diffraction pattern for this nitride. Data have been reported, however, for Ge3N4 which, judging from the similarity between germanium and silicon, might be expected to be isomorphous with Si3N4. An effort was made, therefore, to form such a silicon nitride, to determine its composition and diffraction pattern and, if possible, its structure. To this end a series of three silicon steels was nitrided under controlled conditions with the resultant formation of nitride particles which yielded an electron diffraction pattern in situ. The particles were then extracted from the steel and an attempt was made to determine their chemical composition. X-ray and electron diffraction patterns were also obtained from the extracted particles, which indicate that the nitride is isomorphous with Ge3N4, although a complete determination of the structure has not been possible. These results show that a silicon nitride with a well-defined diffraction pattern can form in silicon steels, and they suggest that this nitride is Si3N4. Materials and Procedures The sillicon steels investigated were In the form of thin sheet or strip and had the composition shown in Table I. The 0.58 and 1.21 pct Si steels were nitrided by holding them at 1110°F in an H2-NH3 atmosphere containing 3 pct ammonia for 48 hr. The nitride particle size was increased by subsequent heating at 1500°F for 13 1/2 hr in helium. The resulting microstructure is shown in Fig. 1. The steel containing 3.20 pct Si was nitrided at 1200°F for 16 1/2 hr after which it was held in helium at 1500°F for 4 hr. Its structure as seen under the electron microscope is illustrated by Fig. 2. As would be expected from the higher silicon content and the shorter holding time at 1500 °F, the nitride particles are smaller and more numerous than those in the 1.21 pct Si steel. The ammonia-hydrogen treatment reduced the carbon content of the steels to a very low level, so no interference was encountered from carbon or carbides. In the case of the 3.2 pct Si steel, the carbon was reduced to 0.003 pct before nitriding by heating in dry hydrogen. Attempts to obtain an X-ray diffraction pattern from polished and etched surfaces of the 1.21 and the 3.20 pct Si steels were unsuccessful. However, an electron diffraction pattern was obtained from the surface of the steels. The interplanar spacings obtained from these patterns arc shown in Table 11, col. 5. The nitride particles were then extracted from all three steels by dissolving the ferrite matrix in bromine-methyl acetate, the solution used in the Beeghly method for the extraction of aluminum nitride from steel. X-ray diffraction patterns of these residues, obtained by means of a spectrometer and by a 57 mm Debye-Scherrer powder camera using filtered cobalt or chromium radiation, are given in Table II along with the pattern obtained by

Jan 1, 1953

By S. L. Craig, C. Orr, H. G. Blocker

WITHIN recent years gas adsorption methods have been developed for measuring the surface area of finely divided materials and have become extremely valuable in research on the corrosion and the catalytic activity of metals. Rather elaborate apparatus is required, and a single determination is so time-consuming that these methods have not been utilized to the fullest extent; the methods are un-suited for most routine control work such as that encountered in powder metallurgical operations and in processes employing metal catalysts. These difficulties are largely eliminated, and surface area is reduced to a routine determination if the liquid-phase adsorption of a surface-active agent such as a fatty acid can be used. When the affinity of the fatty acid carboxyl group for the solid surface is greater than its affinity for the solvent, a unimolec-ular layer of orientated fatty acid molecules will be formed at the solid-liquid interface in a manner similar to that of a compressed fatty acid film on a water surface. The measurement of surface area is then reduced to a measurement of fatty acid adsorption. This propitious circumstance, first investigated by Harkins and Gans,¹ has been employed with somewhat inconclusive results by a number of investigators in evaluating the surface properties of metals, metal catalysts, and metal oxides. The specific surface area values for nickel and platinum catalysts, determined from the adsorption of a number of fatty acids from various solvents, were found by Smith and Fuzek² to agree with values calculated by the gas adsorption technique of Brunauer, Emmett, and Teller," he so-called BET technique. And recently Orr and Bankston4 have also reported good agreement between nitrogen gas and stearic acid adsorption results in the measurement of the surface areas of clay materials. On the other hand, Ries, Johnson, and Melik5 found only order-of-magnitude agreement between these two methods in studying supported, cobalt catalysts having specific surface areas as great as 420 sq m per g; the reason is partially attributable to the very porous nature of the materials. Greenhill,6 investigating the adsorption of long-chain, polar compounds in organic solvents on a number of metal powders, concluded that a uni-molecular layer of stearic acid was formed on exposure of the solid to the acid solution and that the presence of an oxide or another film did not alter this result. Furthermore, the adsorption process appeared to be the same whether or not the sample was degassed prior to exposure to the solution. Greenhill estimated the surface area of one of the powders he investigated from microscopic diameter measurements, and obtained a rough check with surface area evaluation. Russell and Cochran7 found moderate agreement for alumina surface area results by fatty acid and gas adsorption methods. In addition, they also found that the prolonged heating and evacuating pretreatments previously used by investigators were unnecessary. The present work, however, considerably extends these previous investigations, shows that fatty acid adsorption can be used to determine the surface area of a variety of metals and metal compounds, offers further confirmation of the correctness of gas adsorption methods, and presents a simplified technique for the determination of the metal surface area which is suitable for routine work. Experimental Technique Basically, the fatty acid adsorption method is quite simple. It consists of exposing a sample of the material of which the surface area is desired to a fatty acid solution of known concentration. By analysis of an aliquot of the solution, the concentration after adsorption has occurred may be determined. The difference between the initial quantity of acid in solution and the final quantity is that quantity of acid adsorbed by the sample. The specific surface area of the adsorbent material may be calculated from the quantity adsorbed and the weight of the sample. In agreement with the findings of others as outlined above, it was found entirely unnecessary to degas or pretreat the nonporous materials employed other than by drying them thoroughly. However, precaution was necessary so that the dried sample entered the fatty acid solution with little exposure to moisture. The effect of moisture on the interaction of stearic acid with finely divided materials has been thoroughly investigated by Hirst and Lancaster." They found the presence of water merely reduced the amount of acid adsorbed by powders such as TiO2, SiO2, Tic, and Sic. With reactive materials such as Cu, Cu2O, CuO, Zn, and ZnO, however, water was found to initiate chemical reaction. Only with ZnO was reaction observed when the solid and the solu-

Jan 1, 1953

By R. Maddin

IN analyzing the relation between the orientation of new grains and that of the deformed matrix of axially extended and recrystallized single crystals of face-centered cubic metals, a two-stage rotation process" is generally used where the first rotation is made in order to account for an "adjustment of orientation to the environment of strain."&apos; It has been argued that in spite of the difference of orientation, which may amount to as much as 12" (in a brass),&apos; between the octahedral plane as observed in the parent lattice and in the recrystallized grain, it is believed to be a common plane in the sense that it constituted the nucleus in the parent strained crystal from which the new grain grew.&apos; A possible source of the deviation in orientations of a common pole in the new grain and that of the deformed single crystal matrix from which it has grown may be found in the distribution of strain resulting from the plastic deformation. It might be expected in view of the incongruent nature of shear&apos; that the perfection of the octahedral plane along which glide has occurred is disrupted and that this disruption constitutes the strain from which nuclei of new grains can grow during recrystallization. Evidence for the existence of strain along glide planes was first detected by Taylor" in 1927 and substantiated by Collins and Mathewson&apos; in 1940. In their investigations, however, the deformed single crystalline specimens (aluminum) were cut mechanically along the glide planes followed by mechanical polishing. X-ray exposures (glancing angle) of only 8 min with filtered radiation were used. It was later shown&apos; that this type of surface preparation did not remove with all certainty the mechanically disturbed surface. It was felt that a re-investigation of this phenomenon using more refined techniques might reveal a more correct extent of the strain resulting from the deformation which might correlate the deviation of the common pole of the recrystallized grain with the acting slip plane of the matrix crystal. In accordance with these thoughts, a single crystal of a brass (70/30 nominal composition) M in. in diam x 5 in. long, tapered as in previous experiments,&apos; was extended and carefully documented with respect to elongation and shear. Disks about % in. thick paralle&apos;l to the primary slip planes were cut from the specimen by means of an etch cutter." These disks represented volumes of the specimen which had been extended 0, 5, 10, 15, and 20 pct. Copper Ka monochromatic radiation was obtained by reflecting 35,000 v copper radiation from the c-cleavage face of a pentaerythritol crystal. The monochromatic radiation was collimated and led on to the disk set at the proper 0 angle for reflection from the primary (111) planes. The monochromatic beam was aligned in a plane containing the active slip direction. Following a 10 hr exposure at the theoretical Bragg angle, the disk was reset at 0 + 1°, 0 — 1", 0 + 2", 0 — 2", etc., until no Bragg reflection was obtained. The disk was then rotated 90" about its polar axis, and the same X-ray procedure was used. The results are shown in Table I. It may be seen from the results in Table I that the plastic deformation (20 pct elongation) produces fragments of the glide plane which are rotated or tilted as much as 25 " from the normal position on a purely block slip model. In addition to the large variation in 0 angle in the slip direction, there is a variation in 0 as much as 20" in the direction at right angles to the direction of slip, i.e., <110>. In view of the results shown, it may now be argued that the strain distribution finds its origin in the incongruent nature of the slip process.&apos; The use of the two-stage rotation process seems valid in attempting to explain the relation between the orientation of recrystallized grains and the matrix from which they have grown. Acknowledgment This work was sponsored by the ONR under Contract Number N6 onr 234-21 ONR 031-383. The author would like to thank N. K. Chen for reading and correcting the manuscript. References &apos;R. Maddin, C. H. Mathewson, and W. R. Hibbard, Jr.: The Origin of Annealing Twins. Trans. AIME (1949) 185, p. 655; Journal of Metals (September 1949). &apos;J. A. Collins and C. H. Mathewson: Plastic Deformation and Recrystallization of Aluminum Single Crystals. Trans. AIME (1940) 137, p. 150. eN. K. Chen and C. H. Mathewson: Recrystallization of Aluminum Single Crystals After Plastic Extension. Unpublished. 4 C. H. Mathewson: Structural Premises of Strain Hardening and Recrystallization. Trans. A.S.M. (1944) 38. :&apos;C. H. Mathewson: Critical Shear Stress and Incongruent Shear in Plastic Deformation. Trans. Conn. Acad. of Arts and Science, (1951) 38, p. 213. "G. I. Taylor: Resistance to Shear in Metal Crystals, Cohesion and Related Problems. Faraday Soc. (1927) 121. &apos;R. Maddin and W. R. Hibbard, Jr.: Some Observations in the Structure of Alpha Brass After Cutting and Polishing. Trans. AIME (1949) 185, p. 700; Journal of Metals (October 1949). &apos;R. Maddin and W. R. Asher: Apparatus for Cutting Metals Strain-Free. Review of Scientific Instruments (1950) 21, p. 881.

Jan 1, 1953

By A. L. Peyton

The Brewer mine, near Jefferson, Chesterfield County, S. C., was originally operated as a gold mine. As late as 1890 this mine was reported to have been one of the large gold producers in the southeast. Occurrence of topaz on the Brewer property was not reported until 1935, when it was discovered, by Parks3/ and Parks of the Federal Geological Survey while they were investigating gold deposits in the Piedmont province.

Jan 1, 1953

By J. W. R. Rayner

THE conventional method of making water gas involves individual plants for the separate carbonization of coal to coke and the subsequent gasification of coke with steam. The process demands lump coke, preferably made from the best quality of coking coals. The ash in the coke should have a high melting point and the gasification process suffers a loss of efficiency when cokes with law ash-melting points are used. In Britain, these coals are generally the most expensive and they are readily available only in certain localities. The coals not suitable for making lump coke, or yielding only poor quality coke, are much more widely available and are generally cheaper. DEVELOPMENT OF ALTERNATIVE PROCESSES In Germany, processes have been developed and operated commercially for the production of water gas from very low-rank coals such as brown coal and lignites, but much less effort has been spent on processes to use coals of intermediate rank, which are widely available in Britain. The brown-coal processes use coal in the form of either dust or briquettes. The most successful of the dust-gasification methods is the Winkler process, which made a substantial contribution to German oil production during the war. It uses coal in the site range 0 to 8 mm and the fuel bed is blown with a mixture of oxygen and steam at a rate high enough to give it a characteristic boiling motion or, in present-day phraseology, at a rate more than sufficient to fluidize it (Fig. 1). Air cannot be used to provide the heat required for gasification, for various reasons. In the first place, to make the process continuous by mixing air and steam would involve the production of a lean gas-containing much nitrogen. If a separate blow were used, a large amount of potential heat would be lost because the blow gas in such a process would contain a very high percentage of carbon monoxide. Oxygen is necessary therefore and oxygen remains relatively expensive for use in gasification. In the Winkler generator, formation of clinker caused by local overheating does not occur, because of the mobility and high heat transfer of a fluidized bed. These properties of fluidized dusts have been used most successfully

Jan 1, 1953

By V. F. Parry

This report is the first substantial description of the carbonizing process and the details of experimental work conducted at the Denver laboratories under a coopeative agreement between the Bureau of Mines and the Texas Power & Light Co. It presents the results of tests on several Texas lignites and other typical western coals that have been processed in the first pilot plant operated at Denver. Investigations on drying fine coal in the entrained and fluidized state have been under way at Bureau of Mines Denver laboratories for several years. Reports on this work were published in 1949 and 19505/ describing the theory and practice of re-moving inherent moisture from the lower -rank coals. The investigation did not include a study of the removal of surface moisture from fine fuel. Private industry in Canada became interested in the possibilities of drying fine coal, employing the closed-circuit system and techniques recommended by the Bureau. Large, commercial-scale drying units were built by a Canadian company, which successfully demonstrated that surface moisture could be removed from fine coal at high efficiency and capacity ill drying units similar in design to those developed by the Bureau.

Jan 1, 1953

By D. A. Reynolds

THIS PAPER gives results of an investigation of the composition and carbonizing properties of coals from the Beckley bed, Caretta No. 5 mine, Susanna, McDowell County, and Glen Rogers No. 2 mine, Glen Rogers, Wyoming County, W. Va. The investigation included BM-AGA carbonization tests at. 800° and 900° C. and various chemical and physical tests designed to evaluate agglutinating, plastic, and expanding properties of coal. Both coals were of low-volatile bituminous rank, and each was blended with 70 and 80 percent high-volatile A coal from the Pittsburgh bed, Warden mine, Allegheny County, Pa. The Beckley bed was 39 to 58 inches thick at three points in the Caretta No. 5 mine, and the coal was 39 to 49 inches thick. The carbonizing sample contained 83.0 percent fixed carbon on the dry, mineral-matter-free basis. It contained 3.1 percent moisture, 15.8 percent volatile matter, 72.4 percent fixed carbon, 0.7 percent sulfur, and 8.7 percent ash, as carbonized. The ash softened at 2,680° F. The free-swelling index was 7;i, and the agglutinating value was 7.7. This sample fused weakly in the Gieseler plastometer; its blends with 70 and 80 percent Pittsburgh coal attained maximum fluidities of 830 and 600 dial divisions per minute, respectively. The single coal yielded 83.0 percent coke at 900° C. Yields of other carbonization products per ton of coal at 900° C. were: Gas, 9,950 cubic feet; tar, 3.5 gallons; light oil, 1.36 gallons; and ammonium sulfate, 16.3 pounds. Blending with Pittsburgh coal lowered the yield of coke and raised the yields of other products significantly. Caretta coal yielded strong, blocky coke at 900° C., 89 percent of which was plus-2-inch size. Strength indexes of 900° C. coke from 30:70 blends of Caretta No. 5 and Pittsburgh and of Pocahontas No. 3 and Pittsburgh coals were, respectively: 2-inch shatter, 68 and 53; 1%-inch shatter, 90 and 85; 1-inch tumbler, 50 and 53; and %-inch tumbler, 62 and 65. The specific gravity of the 900° C. gas from Caretta No. 5 coal was 0.272, and the heating values were 491 B. t. u. per cubic foot and 2,440 B. t. u. per pound of coal. The blends yielded much richer gas. Yields of tar acids and bases (0.09 and 0.04 gallon per ton, respectively) were within the normal ranges for low-volatile coals. Caretta No. 5 coal expanded 7.5 percent in the sole-heated oven at a charge density of 55.5 pounds per cubic foot. The blends containing 70 and 80 percent Pittsburgh coal contracted 4.8 and 7.5 percent, respectively.

Jan 1, 1953

The Tavua Power Proprietary Ltd. was created in 1936 for the purpose of supplying electric power, compressed air and water to the mining field.The original share capital was subscribed on a two-third:one-third basis by the Emperor Gold Mining Company Ltd. and Loloma (Fiji) Gold Mines, N.L. In 1940, Fiji Mines Development Ltd. (later changed to Dolphin Mines Ltd.) was admitted as a shareholder, and, in 1950, a further change occurred. The present shareholding in the Company is as follows:A central power station was decided upon to reticulate power and compressed air over the whole field and building commenced in May 1936.The original plant comprised three Belliss and Morcom diesel generating sets 770 b.h.p. 525 kW 3,300 V, 3 phase, 50 cycle; one Belliss and Morcom diesel compressor set 2,09&apos;0 cu. ft. of free air per min. at 90 lb. gauge 300 r.p.m., and two small Ruston-Holman diesel compressor sets each of 525 cu. ft. capacity taken over from Loloma (Fiji) Gold Mines, N.L., and the then existing Koroere Gold Mining Company.BuildingThe original building was 130 ft. long by 47 ft. wide with an elevated switchgear annex on the west side from which a clear view of the engine room is available.

Jan 1, 1953