Search Documents

By R. J. Teitel

FOUR or five years ago an investigation was initiated to study and develop basic information on llquid metal fuels for future power nuclear reactors. The objective was to find fluid forms of uranium (solutions or dispersions) in low melting alloys. A summary of the different fuels was presented in a recent article by Teitel, Gurinsky, and Bryner.' The combination of uranium and bismuth, with its low thermal neutron cross section and low melting point, is of basic interest to the development of these fuels. Most of the previous effort on the U-Bi phase diagram was done under security regulation. Ahmann and Baldwin' reported their findings on the U-Bi system in 1945. Their results indicated that the phase diagram had at least two compounds and possibly one more. UBi, and UBi were established by chemical analyses of residues after high temperature centrifugation of alloys. UBi, decomposed peritectically at1980°C and there were signs of another reaction above that. UBi melted at a very high temperature, and there were also signs of a monotectic at high temperatures in high uranium alloys. The solubility of uranium in liquid bismuth has received attention by three groups of authors: Bareis,X ayes and Gordon,' and Ahmann and Baldwin.' The latest and most widely accepted data is that of Bareis, and it is included in Fig. 1 along with new data at higher temperatures. Brewer et al." and Ferro"'' have used X-ray diffraction to determine the number and crystal structure of the compounds. Brewer identified the structure of UBi to be a simple NaCl cubic structure having a cell edge of 6.364A. The density of the compound was calculated to be 11.52 g per cu cm. Two other unindexed patterns were presented as possibly belonging to two other compounds. Ferro agreed with Brewer on the crystal structure of UBi and identified the structure of UBi, and U,Bi,. The intermetallic compound UBi, has a tetragonal cell with a = 4.445A and c = 8.908A. The density of the compound was determined and the number of atoms per cell (six atoms) was calculated. The X-ray density reported was 12.35 g per cu cm. The compound UsBir was treated in a similar way and it was reported to have a cubic structure 9.35A on an edge and to contain 28 atoms per cell. The density was given as 12.59 g per cu cm. Teitel reported that there was a compound UaBi, and no UBi, compound. (The difference in the compositions is 3.3 pct U.) This conclusion was based upon the extrapolation of some 20 tie lines in the

Jan 1, 1958

By R. Kossowsky

USING etch-pit techniques, Johnston and Gilman' have shown that the stress dependence of dislocation velocity can be represented by the expression where r, is the dislocation velocity, a is the applied stress, and oa, is the stress to produce a unit velocity. Noble and Hul12 showed that the exponent m is strain-dependent and increases rapidly in the work-hardening region. This was explained by arguing that in the work-hardened material the applied stress required for any given velocity will be greater than in the annealed material by an amount equal to a back stress due to work hardening. schadler3 has stressed the importance of substructure as a possible source of error in dislocation velocity measurements, and took care to make velocity measurements in which dislocations moved such short distances that interactions with boundaries were avoided. schadler3 also pointed out that, if standard testing equipment is used, measurements of m from flow stress data could be seriously in error in materials with a high initial work-hardening rate. Noble and Hu112 have further argued that, due to the strain dependence of m , the extrapolation to zero strain4 to obtain the true value of m can be justified only in the preyield region. Microstrain experiments in high-purity iron5,6 have led to the conclusion that aiA (Ref. 5) (defined as the stress to first produce a permanent set of 10-6 in. per in.) and oflow are not controlled by the same deformation mechanism. It has been proposed5,6 that aA is governed by the lattice resistance to the motion of screw dislocations in a given slip plane and that oflow is controlled by the lattice resistance to a full-scale cross slip. The purpose of this note is to extend Noble and Hull's argument further and to show that measurements of m from flow stress data can be in error due to the rapid increase in stress in the microstrain region6 when stress is increased beyond aA. Double z-one-refined single crystals of molybdenum (with the (101)[ 111] slip system operating and a Schmidt factor of 0.475) were used in an experimen-

Jan 1, 1968

By C. G. Durdaller, W. H. Robinson, G. M. Pound

The nucleation rate of the a (pay) to 0 (white) tin transformation was measured as a function of temperature and a tin particle size using an X-ray diffraction technique. The powder specimens of a tin were essentially monodisperse and the small dinzension of the particles of these specimens was varied from 13 to 75 p. Several types of nucleation sites of differing potency were fbund to be operative in the nucleation process, but it could not be determined whether these sites were on the free surface of the tin particles or within the volume. Assuming that they were on the free surface, the average density of the most potent sites was calculated to be 2.5 to 5.3 x 10' sites per sq cnz through the application of a Poisson distribztion finction to the isothermal data. Analysis of the temperature dependence' of the rate constmts at a given fraction transformed suggests that the active sites are regions of higher free energy and not catalytic interfaces. Appreciable induction periods were observed at the lower temperatures of transformation. Experimental studies1 of solid-solid phase transformations have led to the belief that the new phase nucleates at structural imperfections. The purpose of the present work was to learn more about the mechanism of nucleation in solids and the nature of the singularities at which nucleation occurs. In this investigation nucleation rates in the isothermal transformation of gray to white tin were measured by an X-ray diffraction technique using essentially monodisperse powders of gray tin. This particular phase transformation was chosen for study because it presented fewer experimental difficulties than most others. The experimental temperature-control problems were minimal because the two phases coexist in equilibrium at 13.3"C, and measurable transformation rates occur at temperatures only slightly above room temperature. The growth rate of the P phase into the a2 is sufficiently fast to make the measured transformation rate equivalent to the nucleation rate, provided that the particle size of the samples is small enough; for the experimental temperatures used in this study, the particle diameter must be less than 100 p. EXPERIMENTAL TECHNIQUE The P tin used in this study was obtained from Capper Pass and Son Ltd., North Ferriby, Yorkshire, England, and was of 99.999 pct purity. It was transformedS to the a phase and ground into a fine powder in an agate mortar. This powder was separated by a Roller air classifier into seven fractions whose dimensions, as determined by microscopic measurement of many thousands of particles, are given in Table I and whose distribution of size within each fraction is given in Figs. 1 and 2. The shape of the particles was roughly that of an oblate spheroid,

Jan 1, 1964

By H. C. Johnson, J. K. Elliott

One of the primary requirements for successful operation of an enriched gas-drive project is to control the composition of injection gas. This can become a serious and difficult problem, particularly in cases where the enrichment material is being furnished from a number of field -produced gas streams. It is possible to effect control of the injection gas composition through frequent or continuous sampling; however, this can be extremely costly and, in many cases, impractical due to laboratory requirements of time. Another alternative would be to provide a calculation technique which would be flexible and sufficiently accurate to predict composition of the liquid and gas streams of interest at any point in the system. The purpose of this paper is to discuss a technique that was used successfully on an operating enriched gas-drive project for developing information which could be used for controlling composition of the injected gas. FIELD OPERATIONS The particular field (hereafter called Example field) in the example operation being discussed is composed of four oil reservoirs (A. B, C and E) and one gas condensate reservoir (D). Casinghead gas from the oil reservoirs and gas from the gas condensate reservoir are gathered through a field gathering system as shown in Fig. I for injection into Reservoir C. The gas mixture which is recovered from the five reservoirs for injection purposes is composed of gases liberated in 19 individual separators, each operating at a separate temperature and pressure. PROPOSED CALCULATION TECHNIQUE It is well known that vapor-liquid equilibrium calculations in general use throughout the petroleum industry can be used to predict reliably the phase behavior of hydrocarbon mixtures, particularly at pressures less than 1,000 psig. It is then a simple matter to account for the material on a ComPonent basis by m''ing flash and material balance calculations at each separation point in a hydrocarbon system. Accordingly, it was proposed to use vapor-liquid equilibrium and material balance cal- culations with a medium-sized electronic digital computer as a basis for developing a control procedure for use in controlling injection gas composition in the enriched gas-drive project. Although the approach is a simple one, the numerous vapor-liquid equilibrium calculations involved make the problem laborious; in this particular case, it would have been impractical to make sutficiently complete analysis without the aid of digital computing equipment. SAMPLING AND VERIFICATION OF CALCULATION PROCEDURE To obtain representative gas and liquid stream samples and to provide a quantitative measure of overall system Performance for comDarative purpLses, a thorough test of the field and plant system was conducted in the summer of 1957. Oil production at each battery was sta-

By P. Bardzil, J. Gurland

An experimental study of the variation of transverse-rupture strength with composition Anexperimentaland grain studysize has shown that the strength reaches a maximum for values of the mean free path between carbide particles of 0.3 to 0.6 microns. The fracture oforiginates in and proceeds through the carbide grains mainly. Impact strength and hardness also were recorded. MOST of the physical properties of sintered carbides vary linearly with composition. The transverse-rupture strength, however, shows a unique behavior. As the amount of binder metal is varied from 6 to 25 pct by weight, the strength at first increases; then, between 15 and 20 pct Co, it reaches a maximum of nearly 400,000 psi, and finally decreases with further additions of binder metal. This behavior of the transverse-rupture strength has been reported, among others, by Englel and Sandford and Trent.' The significance of these observations has not been discussed in the literature. That it may be of more than specific importance is indicated by the very similar variation of strength with composition encountered in other systems sintered in the presence of a liquid phase, such as Tic-Ni3 and Fe-Cu.' Experimental Details All compacts were prepared and sintered according to normal industrial practice. The average diameter of WC grains and the mean free path between grains were measured on metallographically prepared samples by a method of linear and planar analysis sing the relations where d is the average diameter of dispersed grains; Nl is the number of noncontiguous grains intersected on a metallographic plane by a line of unit length; N, is the number of noncontiguous grains per unit area; P is the mean free path between grains of dispersed phase; and f is the volume fraction of dispersed phase. Approximately 1000 grains were counted on each sample. For each composition d2 was plotted against P, the resulting straight lines serving as a check on the measurements. The distribution curves of the WC powders of different average diameters were homologous, and no attempt was made to influence the grain size by blending powders, adjusting the sintering conditions, or otherwise altering the particle size distribution. Densities were measured by differential weighings in air and water. The degree of densification did not vary consistently with either composition or grain size. The density is influenced by slight amounts of impurities, specifically by 0.1 to 0.2 pct Fe which enters the powders during ball milling. As an illus- -tration of the experimental variations, a number of measured densities are listed in Table I. They are expressed in percentage of theoretical density, as calculated from the published X-ray densities of WC and Co.' For the purpose of determining the transverse-rupture strength, rectangular test specimens (3/16x 3/8x3/4 in.) were broken by loading at the center of a 9/16 in. span. The average strength of five or more samples is reported for each composition and grain size. The compacts were ground on two parallel surfaces only. The load was applied at an average rate of 6,800 psi per sec. Since the elongation after fracture of the alloys is very small, it was assumed that the compacts deform elastically to failure and the fracture stress was calculated by the conventional beam formula. The data for one alloy are presented in Table II as an example of the results and scattering ranges encountered. The precision of the test, as measured by the average difference between duplicates, is of the order of 15,000 psi. The results are strictly comparable only to compacts prepared and tested in the manner described and of similar chemical composition and grain size characteristics. Unnotched Charpy specimens were used for impact testing. Each point represents the average of 3 to 20 samples, the larger number being used in an attempt to determine the influence of grain size. Considerable scatter was encountered, the range from lowest to highest value often amounting to 30 pct of the impact strength. The hardness is reported as a Ra reading, using a 60 kg load with diamond brale indenter. Compositions are given in weight percent.

Jan 1, 1956

By R. W. Fenn, H. A. Lepper, W. R. Hibbard

THIS paper reports the results of static tension and torsion tests made on single crystals of alpha brass for the purpose of determining its elastic coefficients. 70-30 alpha brass was chosen because it has been used extensively in the study of the plastic deformation and because it has the following desirable characteristics: (1) face-centered cubic structure, (2) marked elastic anistropy, (3) low elastic modulus. In 1928 Masima and Sachs' using static methods reported the following values for the elastic coefficients of 72-28 pct alpha brass: S11 = 19.4 X 10-13' cm2 per dyne S12 = —8.35 X 10"' cm2 per dyne S44 = 13.9 X 10-13= cm2 per dyne These values were obtained from the measurements shown in fig. 1. The experimental points for both tension and torsion lie consistently below the lines drawn to represent them. Fig. 2 shows the stress-strain curves for their specimens. Only a few points in the elastic range of these curves were available to obtain their values for Young's modulus. Therefore, it was considered that a re-evaluation of these data was desirable. In addition a variation of from 1.13 to 1.485 kg per mm2 was found in the values of the critical resolved shear stress for 70-30 alpha brass reported by Burghoff,² Treuting and Brick: Martin,4 Maddin, Mathewson and Hibbard5,6 and von Goler and Sachs.' Therefore, it was desired to evaluate the conclusion of Boas and Schmid8 that a constant resolved shear stress and not a constant elastic shear initiates plastic deformation. Theoretical Considerations*: The elastic deformation of cubic crystals may be defined by three elastic coefficients (S11, S12, S44,) or three elastic parameters (C,,, C,, C,,). These coefficients or parameters are sufficient to define the stress and strain relations for cubic crystals in the generalized form of Hooke's law referred to Cartesian coordinates. Elastic parameters and coefficients in the cubic system are related by the expressions: C11 —S11+S12/(S11-S12)(S11+2 S12) C12=-S12/(S11-S12)(S11+ 2 S12) (S11 — S12) (S11 + 2 S12) [2] C44 =1/S44 PI It is possible to determine all the elastic coefficients for a cubic metal by measuring two of the three elastic constants: Young's modulus (E), torsion modulus (G), or compressibility (S). The following relations exist between crystallographic orientation and E, G and S for cylindrical crystals of the cubic system: 1/E = S11 — 2 [(S11 - S12) — Su] (?1² ?2² + ?2²?83 + ?3² ?1²) [4]

Jan 1, 1951

By E. L. Kinsella, F. S. White

Solids fluidization utilized in two ways for the commercial production of lime is described. Crushed —6 mesh limestone is dried and dedusted in a single bed reactor, then calcined in a 5-stage reactor. Construction, operation, and results obtained with both processes are given. THE solids fluidization process brought out by the Standard Oil Development Co. in the early forties for catalytic cracking of petroleum enabled rapid transfer of large quantities of heat from gases to solids under closely controlled temperature conditions. As the technique developed, it was natural that applications for the process outside the petroleum industry would be sought. The calcination of limestone to quicklime requires the transfer of a large quantity of heat at high and closely controlled temperatures. For these reasons, this possible application was one of the first to be investigated. Laboratory work conducted by the Dorr Co. indicated that lime produced by solids fluidization would be of exceptional quality. Calculation of theoretical heat balances showed that savings in fuel could be expected. Accordingly, a pilot plant of 10 tons per day capacity was erected by the New England Lime Co. at Adams, Mass., to substantiate the process. Operation of the pilot plant, previously described,' showed that excellent lime could be produced with a saving in fuel. The work also indicated the necessity of preparing feed to remove the finer fractions if dust losses were to be held to a tolerable level. A single-stage fluidized solids drier-stripper was developed to accomplish this sizing.' Subsequently a commercial lime reactor was erected at Adams, beginning operation in June 1949, followed by air sizer facilities completed in November 1951. This paper will describe these two applications of solids fluidization. The raw material for preparation of lime by the fluidizing process is a high calcium crystalline lime- stone having the approximate chemical composition shown in Table I. The stone is first prepared by crushing and grinding in conventional equipment to pass a 6-mesh sieve. After crushing, the material is sent to the FluoDry unit for drying and dedusting. Fluidized Drying and Sizing As shown in Fig. 1, the FluoDry unit consists of a -in. cylindrical steel shell, 9-ft ID by 22-ft 6-in. overall height. Attached horizontallv at the bottom is a 6-ft diam combustion chamber, approximately 7 ft 6 in. long. A refractory constriction dome, consisting of first-quality fire brick shapes, partitions the inside into two sections. The lower section is called the windbox and the upper the bed compartment. The vertical wall of the shell is lined with 6-in. first-quality rotary kiln blocks. In the bottom of the windbox a hoppered section is formed with castable refractory to permit the windbox to be readily cleaned via a 6-in. screw conveyor. The combustion chamber is similarly lined with refractory shapes. On the 6-in. diam section, 4 in. of insulating brick, HW-26, are used. The inner combustion chamber is lined with 4-in. Korundal brick to withstand the high flame temperatures encountered. An 8-in. steel feed pipe, entering vertically through the top and fitted with an air-operated cone valve,

Jan 1, 1953

By F. S. White, E. L. Kinsella

Solids fluidization utilized in two ways for the commercial production of lime is described. Crushed —6 mesh limestone is dried and dedusted in a single bed reactor, then calcined in a 5-stage reactor. Construction, operation, and results obtained with both processes are given. THE solids fluidization process brought out by the Standard Oil Development Co. in the early forties for catalytic cracking of petroleum enabled rapid transfer of large quantities of heat from gases to solids under closely controlled temperature conditions. As the technique developed, it was natural that applications for the process outside the petroleum industry would be sought. The calcination of limestone to quicklime requires the transfer of a large quantity of heat at high and closely controlled temperatures. For these reasons, this possible application was one of the first to be investigated. Laboratory work conducted by the Dorr Co. indicated that lime produced by solids fluidization would be of exceptional quality. Calculation of theoretical heat balances showed that savings in fuel could be expected. Accordingly, a pilot plant of 10 tons per day capacity was erected by the New England Lime Co. at Adams, Mass., to substantiate the process. Operation of the pilot plant, previously described,' showed that excellent lime could be produced with a saving in fuel. The work also indicated the necessity of preparing feed to remove the finer fractions if dust losses were to be held to a tolerable level. A single-stage fluidized solids drier-stripper was developed to accomplish this sizing.' Subsequently a commercial lime reactor was erected at Adams, beginning operation in June 1949, followed by air sizer facilities completed in November 1951. This paper will describe these two applications of solids fluidization. The raw material for preparation of lime by the fluidizing process is a high calcium crystalline lime- stone having the approximate chemical composition shown in Table I. The stone is first prepared by crushing and grinding in conventional equipment to pass a 6-mesh sieve. After crushing, the material is sent to the FluoDry unit for drying and dedusting. Fluidized Drying and Sizing As shown in Fig. 1, the FluoDry unit consists of a -in. cylindrical steel shell, 9-ft ID by 22-ft 6-in. overall height. Attached horizontallv at the bottom is a 6-ft diam combustion chamber, approximately 7 ft 6 in. long. A refractory constriction dome, consisting of first-quality fire brick shapes, partitions the inside into two sections. The lower section is called the windbox and the upper the bed compartment. The vertical wall of the shell is lined with 6-in. first-quality rotary kiln blocks. In the bottom of the windbox a hoppered section is formed with castable refractory to permit the windbox to be readily cleaned via a 6-in. screw conveyor. The combustion chamber is similarly lined with refractory shapes. On the 6-in. diam section, 4 in. of insulating brick, HW-26, are used. The inner combustion chamber is lined with 4-in. Korundal brick to withstand the high flame temperatures encountered. An 8-in. steel feed pipe, entering vertically through the top and fitted with an air-operated cone valve,

Jan 1, 1953

By Oliver Bowles

AMONG mining men as well as in the popular mind the conviction has held sway that mining is pre-eminently a western industry. True it is that gold, silver, copper and other metals have made the States of California, Colorado, Montana, Utah. Nevada and Arizona famous. The prominence attained by these States as mineral producers is, however, not measured alone by the money value of the products of their mines. While the metals are without doubt indispensable in industry, the glamour of the precious metals, and the lure of copper, lead and zinc have given to their ore deposits a sentimental interest that often quite out-weighs their commercial importance. Today a great group of more commonplace minerals are finding a place in commerce and industry rivaling that of the metals, but there is little sentiment attached to them, and,. therefore, they attain relatively little publicity. This is the great group of the non-metallic minerals, exclusive of fuels and oils, including stone, sand and gravel, cement, lime, gypsum, asbestos, mica, phos-phate rock and many others. Almost unnoticed they have grown in production to almost unbelievable pro-portions. The estimated value of metal production for 1925 is given as $1,380,000,000, of the non-metals (ex-cluding fuels) $1,294,000,000. The non-metallic industries are not new, many of them date back almost to pre-historic times; but, as the greatest of them (on a tonnage basis) provides raw materials for the construction industries, it required the activities of the present age of construction to bring about their enormous development. Many of them enter manufacturing as well as con-struction. Non-metallic minerals constitute the back-bone of our great chemical industries. While construction and manufacture reach to all parts of the country their widest development has been in the great industrial centers of the eastern Seaboard and the middle West. Consequently the raw materials of mineral origin required for these great industries have attained a remarkable growth in the eastern half of the- United States. In compiling figures of mineral production for 1924, for which more complete data are available than for later years, the surprising fact is brought to light that the non-metallic mineral produc-tion alone of some of the eastern and middle-western States exceeds by a substantial margin the total min-eral production of some of the western States that have been classed as essentially mining States. Thus the non-metallic mineral production, exclusive of coal and petroleum, of the State of Ohio, was approximately $150,000,000; of Pennsylvania $175,000,000; and of New York $107,000,000. For the same year, 1924, the total mineral production of Utah was $84,357,000; of Montana $70,632,000; of Colorado $61,488,000; and of Nevada only $26,226,000. Even Minnesota, with its enormous iron ore production, reached only $107,845,-000, or a sum about equivalent to the non-metallic min-eral production of the State of New York.

Jan 8, 1927

Jan 1, 1925

By M. V. Lowry

This paper outlines the economic considerations that led to the recent installation of a thickener at St. Joseph LeadCo.'s Balmat, N.Y. mill. To incorporate storage of concentrates, they decided upon a single, unusually deep tank to be used for both storage and thickening. The abnormally high rake lift required was achieved by the novel feature of having the entire drive platform raise and lower. Initial operating problems are described along with the satisfactory solutions. Total costs for concentrate handling before and after installation of the storage thickeners are compared. In Northern New York State, the St. Joseph Lead Co. conducts a 2100 tpd zinc mining and milling operation at its Balmat Plant. Conventional crushing, grinding, and flotation is used to produce a zinc concentrate. For 32 years, from 1930 through 1962, the plant operated with the concentrates going directly from flotation to the filtering, drying, and loading facilities. All of the concentrate handling equipment, therefore, had to operate 24 hrs per day. It also had to accommodate wide fluctuations in tonnage, due to variations in the grade of ore. Many problems were thereby encountered in filtering and drying, but it was never concluded that the cost could be justified for installing a conventional, large diameter thickener. Finally, in 1963, they installed an unconventional thickener that is unusual in several respects. The tank depth is 16 ft instead of the normal 8 ft. The rakes are raised and lowered by having the main drive gear located on a movable platform. Automatic controls are programmed to raise the drive platform and rakes during one shift of storage. During the next two shifts of withdrawal, the controls are programmed to lower the drive platform and rakes. After three years of operating this unique storage-thickener, the conclusion is that a correct choice was made from several alternative schemes for storing concentrates. The various considerations involved in the final selection will here be analyzed, and the design features and installation details will be de- scribed. Operating problems and modifications made to the equipment will next be considered, and finally the effects upon filtering, drying, and loading will be reported. SELECTION CONSIDERATIONS Even without a thickener, concentrate handling had become reasonably efficient at the Balmat Mill by the year 1962. A tonnage that varied between 6 and 25 tph was being handled fairly satisfactorily. The filter cake moisture of 8%% seemed quite respectable, except that two large filters were usually in service. Three filters often had to be operated in order to prevent excessive filter overflow with consequent loss of values. This situation occurred when zinc concentrates from flotation exceeded 20 tph and when filter cloth blinding developed. Over the years, numerous small improvements had been effected, such as: selection of a filter cloth with better flow characteristics; addition of flocculant to the filter feed; and, in 1953, the smallest of three drum filters was replaced by a five disc, 8' 10" diam filter with a bottom agitator and snap blow. As another example of fairly efficient operation, the oil-fired dryer was doing a seemingly satisfactory job of further reducing the moisture content to an average of 3%. However, there were often considerable dust losses when the tonnage suddenly dropped off to 6 tph. At high tonnage rates, the resulting high moistures of 4% and 5% caused difficulties due to concentrates sticking and freezing in chutes leading to the box car loaders. (Drying of concentrates is justified because of the high freight rate for the long shipping distance to the company owned smelter at Josephtown, Pa. near Pittsburgh.) It was long realized that installation of a thickener would permit the subsequent steps of concentrate handling to proceed more smoothly and would alleviate the problems existing in the filtering, drying, and loading operations. It was also realized that even a slightly lower filter cake moisture could mean considerable savings in fuel oil. However, all these factors were never quite sufficient to warrant the expense of a thickener until three more considerations were added to the picture. First, the advent of flocculants meant that a thickener of relatively small area could now be considered. Secondly, a complete renovation of the zinc flotation circuit was made between 1957 and 1961. The

Jan 1, 1967

By Edmund Davenport

Tier; production of thorium of high purity by the Ca-CaCl2 reduction has been described by Marden and Rentschler,1 who also reported some of the properties of the coherent, ductile metal obtained from this pure thorium powder. The present paper describes the properties of thorium produced by the Ca-CaCl2 process modified in some details to meet commercial conditions. The principal effect of these changes in process has been an unavoidable increase in the oxide content of the thorium.

Jan 1, 1929

James W. Malcolmson died suddenly on Dec. 26, 1917, at Kansas City, Mo., where he had made his home for the past ten years. He was born at Dover, Kent, England, on Oct. 6, 1866. He graduated from the Royal School of Science, London, England, in 1889, and almost immediately after graduation came to Mexico, accepting a position with the Michoacan Railway and Mining Co., as mining and mechanical engineer. His work in the mining profession was carried on principally in Msxiac and the United States. • In 1888, he married Katherine Haden Krause, of Woolwich, Kent, England, and leaves, besides his wife, five sons and one daughter. During Mr. Malcolmson's long and successful career as a mining engineer, he was connected with the following companies: from 1889 to 1893, with the Michoacan Railway and Mining Co., as mining and mechanical engineer; from 1893 to 1898, in various capacities with the Kansas City Smelting & Refining Co.; after the consolidation of the Kansas City Smelting & Refining Co. with the American Smelting & Refining Co., he remained as manager of the mining department in Mexico of the American Smelting & Refining Co. until 1902. In 1902, he located in El Paso, and took up the practice of his profession as a consulting engineer. While there, he was consulting engineer for the famous and rich Pedrazzini mines at Chispas, in the State of Sonora. He was instrumental in organizing the La Republics mine in Chihuahua, and for a time acted as consulting engineer for the property. He remained in El Paso until 1907 and then moved to Kansas City and became associated with the United States & Mexican Trust Co., as consulting engineer. In 1909, he became connected with The Lucky Tiger Combination Gold Mining Co., as its consulting engineer, and continued in this connection and in the general practice of his profession as consulting engineer until his death.. His general policy in connection with the Lucky Tiger company was always a progressive one and the success of the enterprise can be largely attributed to him and his good judgment. Mr. Malcolmson contributed several articles to the Institute at different times, one of them being on the ore deposits of the Sierra Mojada Mining District, in 1901. Much of his work was in Mexico, and during his long residence in that country he acquired a very thorough knowledge of the Mexican people and their customs. During the revolution, from 1910 to 1916, this knowledge was of great value in connection with his work for the Lucky Tiger company, and often assisted greatly in keeping the property going. Mr. Malcolmson was one of the very widely known men in his profession; he was everywhere held in the very highest regard, and his position among men in the mining profession was an enviable and honorable one. At the time of his death, besides being consulting engineer for the Lucky Tiger company, he was interested in mines in the Miami zinc fields and was acting as consulting engineer for two of the operating properties there. He invested to quite an extent in real estate when he moved to Kansas City in 1907 and his investments in this line proved successful.

Jan 1, 1920

By H. R. Wuthrich

The Metallgesellschaft AG decided in late 1965 to build an Electrolytic Zinc Plant at Datteln (W. Germany). Lurgi-Chemie was entrusted with the engineering and erection of the entire plant. Ground was broken in February 1967 and the operation was started on August 1st, 1968. The new Electrolytic Zinc Plant was designed to produce a minimum of 100,000 metric tons of special high grade zinc and 200,000 metric tons of sulphuric acid. Concentrates from Meggen (W. Germany) and mainly Timmins (Canada) are roasted in two turbulent layer roasters. The sulfur dioxide containing gases are converted in a "Bayer double catalysis unit" to sulfuric acid. The calcine is leached batch wise, the leach residue separated from the pregnant solution by counter-current thickeners and drum filters. For maintaining the sulfate balance a modified jarosite leach is being used. After a two step purification the neutral solution is mixed with spent electrolyte and cooled in unpacked atmospheric cooling towers. Three electrical circuits are supplying the power to the tankhouse, each rated at 30,000 amperes. With a maximum current density of 750 amperes per square meter and a stripping cycle of 24 hours, an average current efficiency of 90 percent is obtained. Cathodes are melted in one induction furnace and cast into shapes, or alloyed with aluminum and copper for die-cast metal.

Jan 1, 1970

By H. M. Hobart

THIS paper deals principally with investigations undertaken by the Welding Research Sub-committee of the Welding Committee of the Emergency Fleet Corporation. The general object of the investigations has been to extend the use of welding in the construction of merchant ships and, specifically, to provide a definite basis for obtaining the best economy and efficiency in employing welding in place of riveting in the construction of the hulls of such ships. Composition of Ship-plate Steel The chemical composition of the steel employed in such hull construction varies with the thickness of the plates. Through the courtesy of Mr. H. Jasper Cox of Lloyd's Register of Shipping, the following information may be given concerning the kind of steel plate employed in American Shipyards in 1918 for the hull construction of merchant ships. Lloyd's requirements do not relate to the chemical composition. They require a tensile strength of 58,000 lb. per square inch (40.75 kg. per sq. mm.) for their lower limit and 72,000 lb. per square inch (50.59 kg. per sq. mm.) for their upper limit. For the information of the Committee, Lloyd's obtained from their surveyors at various works data of the carbon content, which is as follows:

Jan 2, 1919

By C. W. Spencer, Che-Yu Li, R. J. Knight

The usual reaction product for the monotectic reaction in the Bi-Se system consists of rod -shaped particles of selenium-rich liquid embedded in a single crystal matrix of At certain crystallo-graphic orientations of the matrix with respect to the reaction interface, more complex shapes are as -sumed by the liquid particles. This reaction has been examined at different growth rates and relative crystallographic orientations of the matrix with respect to the reaction interface. The uhriation in auerage particle size of the liquid phase with reaction rate has been determined at one crystallograpIzic orientation of the matrix. On a plot of logarithm of average particle diameter vs logarithm of reaction rate, data points for crystals grown at rates of 10- to 1.0 cm per hr fall near a curve of slobe -0.4. MONOTECTIC reactions in binary alloy systems are reactions of the eutectic class in which, as the system is cooled through the three-phase reaction isotherm, one liquid phase (L) decomposes to a solid phase and another liquid phase (LII).' A partial phase diagram, as taken from Hansen, showing the monotectic reaction in the Bi-Se system is given in Fig. 1. This diagram specifies the monotectic point at 618°C and 72 at. pct Se, and the monotectic reaction products as the intermetallic Bi Se3 and a liquid (LII) which contains approximately 98 at. pct Se. At a lower temperature, 217°C, this liquid may undergo a eutectic reaction in which the reaction products are BizSe3 and crystalline selenium. However, under conditions of rapid cooling, or quenching, from above 217°C, this selenium-rich liquid may be partially retained to room temperature in an amorphous or glassy state. The intermetallic BizSe3 is rhombohedral, of the space group jm;' however, for convenience it is usually represented by a hexagonal struture. A pronounced plane of cleavage, which lies perpendicular to the main axis of the rhombohedral unit cell or parallel to the basal plane of the hexagonal cell, exists in the structure. The usual monotectic reaction product consists of rod-like particles of LII embedded in a single-crystal matrix of BizSe3, although at certain crystallographic orientations of the matrix BizSe3 other more complex shapes are assumed by LII. A similar rod-like, or cylindrical, morphology for the carbide phase has been reported by westbrook7 in the a Cr-Crz3Ce eutectic structure. In this paper the morphological characteristics of the LII particles, as retained to room temperature, have been examined under conditions of varying growth rate and crystallographic orientation of the matrix BizSe3 with respect to the growth direction. EXPERIMENTAL PROCEDURE Alloy specimens corresponding to the monotectic composition, 72 at. pct, or 50 w pct Se, were prepared from 99.999 pct pure bismuth and selenium obtained from the American Smelting and Refining Co. The two elements, corresponding to a total specimen weight of approximately 30 g, were encapsulated in 13 mm OD Vycor tubing under a vacuum of 5 x X mm of Hg. The capsules were suspended on a fine platinum wire in a Bridgman-type furnace which exhibited a temperature gradient of

Jan 1, 1963

Abbott, Robert H., (S'42) Agricultural & Mech. College of Texas, College Sta.. Texas. Abrahamson, Guy C., (S'43) Univ. of California, Berkeley. Calif. Abrego, Alfredo, (S'43) Texas College of Mines & Metallurgy, El Paso, Texas. Ackermann, K. G., (S'43) Univ. of Alabama, University, Ala. Adamec, Lew, (S'42) Colorado School of Mines, Golden, . Colo. Adams. Charles E., (S'42) Univ. of California, Los Angeles, Calif. Adams, Charles W., (S'30) Asst. Met., Canada Foundries & Forgings Ltd., Welland, Ont., Canada. Adams, John W., (S'42) Univ. of Texas, Austin, Texas. Adams, Karl S., (S'43) Univ. of New Hampshire, Durham, N. H. Adamson, Charles R., (S'41) Univ. of Utah, Salt Lake City. Utah. Adler, A. G., (S'41) Met. Engr., Flotation Operator Helper. Utah Copper Co.. Garfield, Utah. Adler, Frank J., (S'42) Colorado School of Mines, Golden, Colo.

Jan 1, 1943

By H. S. Bell

IT SEEMS unnecessary to dwell upon the advantages of the modern pipe still as compared with the older type of distillation equipment used by oil refiners. The relatively low installation cost, coupled with remarkable operating efficiencies of pipe stills, precludes the consideration of other types except in rare instances where some peculiarity of product or plant may have an influence. The question of the actual heat required to distil petroleum is quite involved. We have extensive data on the latent heats of the various hydrocarbons under different conditions of pressure. We also have information regarding the specific heats of various oils and the effect of temperature thereon. Because of the complexity of petroleum and of each fraction, it seems impossible to theoretically analyze the partial-pressure effect of the great number of hydrocarbons upon one another during distillation. If a distillation curve and percentage analysis of any crude or product are available, it is possible to construct a curve with ordinates representing per cent. distilled and B. t. u. per pound or per gallon, or other desired unit. To do so the crude is split into fractions, of 5 or 10 per cent. The boiling point and gravity of each fraction being determined, it is possible to evaluate the heat required. As each fraction is removed, the residue must be raised to a higher temperature and latent heat supplied for the successive fraction. As the calculations progress, the latent heats decrease while the specific heats increase. Such a curve is illustrated by Fig. 1 for a typical 39.9 B° North Texas crude.

Jan 1, 1928

By F. C. Kelley, L. L. Wyman

In order to clarify and amplify the existing data concerning the action of the cementing material in cemented tungsten carbide alloys, the authors have initiated this investigation of the entire range of cobalt-tungsten carbide alloys. Inasmuch as the ultimate objective is relative to what actually goes on during the sintering of cemented tungsten carbide materials, this work was necessarily restricted to heat treatments similar to those used in actual production of these materials. In the course of numerous experiments, the authors have noted several conditions that indicated that there was a solubility to be considered. Among these factors are the following: 1. Many of the alloys showed a much larger amount of binding constituent to be present than could possibly be accounted for by the cobalt content. 2. In many areas, grains of the carbide constituent are much larger than the particles of carbide originally added. In addition, these grains are of very regular contour. 2a. In samples of cemented tungsten carbide which had been fused in the atomic hydrogen torch in the presence of excess binder constituent, immense grains are formed, and their shapes are very regular. This is also true when the cemented tungsten carbide of 13 per cent. Co content is fused alone in the atomic hydrogen torch. Contrary to general expectation, chemical analysis of this material, after fusion in the atomic hydrogen torch, checks the analysis of unfused material. 3. In making the cemented tungsten carbide materials by the process of exerting the pressure at the time of heating a certain portion of the ' contents squeezed out of the mold. Chemical analysis has shown that this material contains approximately 12 to 20 per cent. of tungsten. The microstructure shows a cored dendritic structure interlaced with eutectic network, and some graphite, as shown in Fig. 1. 4. Thermal analysis of these materials has consistently indicated an arrest point close to 1350" C.

Jan 1, 1931

By W. R. Shimer

IN his valuable report on Finishing Temperatures and Properties of Rails, I Dr. G. K. Burgess, Chief of the Division of Metallurgy, U. S. Bureau of Standards, has begun a line of investigation which should be continued by those interested in the subject, and who have proper facilities for carrying put the work. For the past year or more the Bethlehem Steel Co. has been conducting experiments to learn the effect of rail finishing temperatures on their physical properties and microstructure and the results are here given for the consideration of those interested in the rail situation. . Considerable differences of opinion have been expressed by various authorities, in the past, as to the effect of large or small grain size and high or low finishing temperatures of steel rails on their physical properties and wearing qualities. Low finishing temperatures and, therefore, low shrinkage, have been advocated on the theory that the wearing qualities would be improved. Others have recommended high finishing temperatures. The generally accepted cause for rail failures, due to the development ,of transverse fissures, is excessive wheel pressure on hard rails. One of the causes advanced for hard rails has been that they contain too high per centages of carbon and manganese; another that the rails were finished at too low a temperature, i.e., at or near the critical point. In the experiments herein described the rails were rolled from reheated blooms. All the rail blooms were charged hot in a reheating furnace and brought up to about the original ingot-rolling temperature before rolling into rails. These rails gave better results in deflection, withstood a greater number of drops before breaking, and showed greater ductility, than. rails of identically the same composition and section which were rolled, direct from the ingot. Rails rolled from reheated blooms, finished at somewhat higher temperatures than when rolled direct from the ingot, have a different microstructure, which the writer does not believe is due so much to the difference in finishing temperatures, as to the difference in

Jan 3, 1915