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By L. B. Pankratz

The Bureau of Mines measured heat capacities of alpha and beta spodumene (LiAlSi2O5) and of beta eucryptite (LiAlSiO4) over the temperature range 51° to 298° K. The entropies at 298° K were found to be 30.9 ± 0.2 cal/deg mole for alpha spodumene, 36.9 ± 0.3 cal/deg mole for beta spodumene, and 24.8±0.2 cal/deg mole for beta eucryptite. High-temperature heat content measurements above 298° K were conducted for the same compounds. Measurements were made to 1,150° K for alpha spodumene, 1,600° K for beta spodumene, and 1,470° K for beta eucryptite. Tables of heats and free energies of formation are given from the elements and from the constituent oxides.

Jan 1, 1967

By Wilson Blake

The Bureau of Mines used a mathematical model based on the finite element method of stress analysis to calculate stresses and displacements surrounding an open pit mine in a gravity-loaded rock mass. Comparison of the finite element solution for a semicircular notch in a gravity-loaded plate with the theoretical solution for a semicircular notch in a plate under uniform compression parallel to the free boundary demonstrates the inapplicability of the latter method to openings at the free surface of a gravity-loaded medium. High stress concentrations are formed at irregularities along the boundary of an open pit in a gravity-loaded continuous competent rock; however, for this type of rock the magnitudes of the stresses are too low to be considered a major factor in open pit slope stability. High stress magnitudes will occur if, in addition to the gravity stress field, a large horizontal stress field exists.

Jan 1, 1967

By A. W. Deurbrouck

This Bureau of Mines report describes the preparation characteristics of the significant coalbeds from which samples could be obtained in Upshur County, W. Va. One of the 14 samples collected was of metallurgical quality as received, 6 could be sufficiently upgraded to provide acceptable products, and 7 could not be upgraded to metallurgical quality because of their high sulfur contents.

Jan 1, 1967

By Bernard Porter

The rate of the heterogeneous reaction between reactor-grade yttrium and lithium fluoride in lithium fluoride-yttrium fluoride mixtures was measured using a quartz spring balance. At 950° C the magnitude of the rate of reaction is 10-5 grams of yttrium/cm2-sec. The heat of activation for the reaction is 38.3 kilocalories per mole of LiF. A surface-controlled mechanism is proposed in which LiF is adsorbed on the yttrium metal surface. An activated complex is formed when additional LiF reacts with the adsorbed LiF-metal site. The activated complex then decomposes to the products) which are lithium metal and YF3. The importance of the reaction in the electrowinning of yttrium metal from fluoride electrolytes is discussed.

Jan 1, 1967

By Leroy Dockter

The grinding characteristics of lignite in a ball mill were investigated. The variables studied were initial lignite moisture content, degree of in-the-mill drying, and lignite source. The mill tested was a pilot-p1ant-size conical ball mill which had a maximum output of from 80 to 180 lb/hr pulverized product depending on the lignite and test conditions. The capacity of the test mill ranged from 82 to 103 lb/hr depending upon mine source, in pulverization of as-mined lignite with minimum drying, The capabilities of the ball mill could not be correlated to Hardgrove index of the individual lignites or other observed physical properties. Predrying lignite from its 35 to 40 percent raw moisture content to about 10 percent moisture before grinding improved the mill capacity 87 percent, compared to an increase in capacity of 74 percent with in-the-mi11 drying to the same product moisture.

Jan 1, 1967

By R. V. Higgins

This report presents computer instructions for calculating the performance of three-phase flow of gas, oil, and water. The calculated results for an illustrative example are presented. The example is the waterflood of a reservoir containing free gas in the reservoir as a result of the partial depletion of the oil by the expansion of the gas initially in solution. The flood pattern for the example is a 5-spot.

Jan 1, 1967

By W. E. Anable

The Bureau of Mines studied the purification of commercially available vanadium in the 100-kw electron-beam furnace. Purification studies were conducted on a 100-gram button scale by melting and holding the liquid vanadium at temperatures ranging from 2,060° to 2,080° C at pressure of 5(10)-5 torr for periods ranging from 5 to 20 minutes. The effect of doping vanadium with carbon and metallic additions was determined. This study demonstrated that hydrogen was readily removed to 3 ppm or less, oxygen and carbon were reduced to less than 100 ppm each, and the metallic impurities were reduced Co the range of 10 to 500 ppm. The nitrogen content was not reduced in any of the buttons; rather, the nitrogen concentration generally increased as samples were held for successively longer periods. Oxygen was removed much faster and more completely when vanadium was doped with small carbon additions or one of several dopes prior to melting.

Jan 1, 1967

By Stephen D. Cramer

The objective of the present studies was to develop thick adherent and coherent coatings of platinum and palladium on refractory metals and other substrates of industrial and engineering importance. Existing platinum and palladium electrolytes were modified to make them suitable for the electrodeposition of thick deposits. The optimum operating conditions for these electrolytes were established. Pretreatment procedures for columbium, copper, graphite, molybdenum, nickel, stainless steel, tantalum, titanium, tungsten, vanadium, and zirconium substrates were studied. New pretreatment procedures for columbium, molybdenum, stainless steel, tantalum, tungsten, and nickel were developed. The internal stress and hardness of selected electrodeposits were measured. The effects of heat treatment upon the properties of electrodeposits were studied.

Jan 1, 1967

By Heinz W. Sternberg

A method for the electrochemical reduction of the benzene ring was developed and applied to the electrochemical reduction of coal. Successive electrochemical reductions of a vitrain from low-volatile bituminous coal in ethylenediamine saturated with lithium chloride resulted in the addition of 53 hydrogens per 100 carbon atoms. Ultimate analyses and pyridine solubility of the vitrain recovered after each reduction showed that hydrogen added at the beginning has a much greater effect on solubility than hydrogen added at a later stage. Surprisingly, the removal of sulfur from the vitrain takes place only after the more reactive aromatic rings are reduced. Nuclear magnetic resonance analysis and average molecular weight determination of the extracts of the reduced vitrain samples, representing about 18 percent of the vitrain, showed that these fractions had 95 percent of their hydrogen content on saturated carbon atoms and an average molecular weight of 800 to 900. A study of the effect of operating variables on current efficiency showed that current efficiency is highest with aluminum as cathode material and with lithium chloride as electrolyte. A substantial increase in current efficiency of difficulty reducible olefinic double bonds was achieved by adding a proton donor. This result is significant in connection with the electrochemical reduction of coal which proceeds from readily reducible aromatic double bonds to difficultly reducible isolated double bonds. It is proposed that reduction is achieved by electrolytically generated and subsequently solvated electrons and hence does not require prior adsorption of the substrate at the electrode surface. This offers a distinct advantage for electrolytic reduction of sparingly or insoluble substrates such as coal.

Jan 1, 1967

By C. C. Merrill

Studies were made to determine the amenability of yttrium to fused-salt electrorefining in a controlled atmosphere. Tests were conducted in a LiCl- YCl3 electrolyte system at 710° C. The major variables studied were the YCl3 content of the electrolyte, from l.7 to 13.4 mol percent, and the initial cathode current density, from 410 to 1,630 amperes per square foot. Vacuum distillation was employed to remove salt from the deposited metal. Metallic impurities, except for lithium, could be reduced to near or below their lower analytical limits, ranging from 10 ppm for Cu to 300 ppm for Ta; reduction of oxygen content, however, was accomplished only in metal produced from electrolytes with 5.4 mol percent YCl3 or less. Initial cathode current density had little effect on the purity of the product.

Jan 1, 1967

By Robert E. Barieau

This report describes a method for treating pressure-volume-temperature (PVT) data obtained with a Burnett compressibility apparatus. The method makes use of a general nonlinear least-squares technique developed at the Bureau of Mines Helium Research Center. It is assumed that an adequate functional form is available for the expression of the compressibility factor as a function of either the molal density or the pressure. The functional form of the compressibility factor can be either linear or nonlinear in the parameters to be evaluated. Formulas are given for calculating variances and covariances of all parameters evaluated and for calculating the variance of calculated quantities of interest.

Jan 1, 1967

By D. Bienstock

The use of alkalized alumina in removing sulfur dioxide from a coal-combustion flue gas at 625° F was investigated on a pilot plant scale. The absorber was 26 feet long and 1.6 inches ED. Counter-current gas-solids flow at gas velocities of 8 to 15 ft/sec in the presence and absence of baffles, as well as solids entrainment at gas velocities of 20 to 23 ft/sec with solids recycle, were employed. The spent absorbent as regenerated as fixed bed with the reducing gases--reformed natural .7.7d hydrogen. Of absorption-regeneration were successful completed using the alkalized alumina rolled into spherical granules 10 to 16 mesh. There was no loss in activity of absorbent toward SO2 with a modest attrition equivalent to 0.l percent of the solids feed. Supporting studies were conducted on the effect of the sodium content in the absorbent, the composition of the reducing gas, thermal treatment to increase absorbent hardness, and removal of absorbed chlorine from the absorbent. A mathematical model was formulated to describe the removal of SO2 by alkalized aluminum from fixed and falling beds.

Jan 1, 1967

By L. C. George

The Bureau of Mines measured vapor pressures of selected mixtures in the binary system SnCla-ZnC12 by the static pressure method. Equations expressing the vapor pressure) and the heat and free energy of vaporization) as functions of temperature were developed by numerical analysis based on the sigma-plot method. It was found that the vapor pressure of any SnCl2-ZnCl2 mixture) at any temperature within the range of this investigation) could be accurately calculated from the derived values for the heat and free energy of vaporization for the mixture, with a probable error of 0.01 cm Hg or less.

Jan 1, 1967

By Manuel Gomez

Published experimental coke data from a pilot plant slot-type oven were examined by statistical regression analysis. Quantitative relationships were found to exist between the coking rate, bulk density, and fine grinding of the coal, sole-oven expansion, volatile matter, moisture, ash, and carbon con-tent of the coal and coke parameters indicative of size and strength. Regression equations developed from coke data were shown to yield computed values that were in good agreement with experimental results for 11 coke properties. Prediction equations developed were evaluated with an independent set of data. Present results indicate that the variables cited undergo much interaction and the sum of these interactions determines coke size and strength.

Jan 1, 1967

By Alla D. Mah

Heat content and entropy data at high temperatures were obtained for cuprous oxide (Cu2O) and cupric oxide (CuO). Experimental results and smooth values are reported. Equations are given for heat content increments and heat capacities above 2980 K. Low-temperature heat capacity data were obtained for cuprous oxide. Evaluation of the 2980 K entropy gave, S°298.15(Cu2O) = 22.08 ± 0.10 cal/deg mole. Heat of formation values were determined for cuprous and cupric oxides. The values are: AH°298.15(Cu2O) = -40,830 ± 300 cal/mole, and AH°298.15(CuO) = -37,230 ± 150 cal/mole.

Jan 1, 1967

By Theodore Kessler

The purpose of this Bureau of Mines investigation was to determine what new organic compounds or high concentrations of a particular organic species can be formed by exposure of coal derivatives to ultrasonic energy. Tetralin, l-methylnaphthalene, and pyridine were used as model compounds. Gaseous and solid reaction products resulting from the ultrasonic irradiation of these coal derivatives were determined using mass spectrometry. Products from the irradiation of tetralin were studied as a function of time, atmosphere, and sample size. The sonolysis (chemical reactions produced by ultrasonic energy) of tetralin and l-methylnaphthalene produced C2H2, HCN, CH4, H2, CO, and CO2, depending upon the experimental conditions. The ultrasonic irradiation of tetralin also produced diacetylene under certain experimental conditions. The cleavage of organic chemical bonds by ultrasonic cavitation in the absence of water was also observed in this study.

Jan 1, 1967

By Webster S. Anderson

The design, development, and testing of hydraulic props to provide a lightweight, high strength, recoverable unit is described. Modifications in design incorporating threaded components resulted in the development of a lightweight hydraulic prop fabricated from aluminum alloy tubing. This new design facilitates interchange and replacement of component parts, and the physical properties of the material are not changed as they are when welding is required. The new prop is 65,000 pounds and has a maximum load capacity of a lower weight-to-load capacity ratio than the hydraulic props now available.

Jan 1, 1967

By Robert C. Bates

Variations in water percolation rates through saturated cohesionless hydraulic backfill (mill tailings) have been studied in relation to the many physical aspects of the system to determine the most important factors in causing these variations. A multivariable least-squares regression analysis of 135 separate tests shows that a reliable estimate of the water percolation rate through typical hydraulic backfill can be made if the bulk density (unit weight), specific gravity, and grain-size distribution are known or can be estimated. Equations for predicting percolation rate, coefficient of permeability, and seepage velocity are developed both for the range of data analyzed and for extrapolation. The prediction equations for use within the range of data studied are quite accurate, while the ones developed for extrapolation are less accurate but still give reasonable approximations of flow rates. The equations given are valid for cohesionless materials that are free of clays and micas, exemplified by classified mill tailings. The equation developed for predicting percolation rates is as follows: 1nP20 = 11.39147 + 2.853422 1n(VR X D10) + 0.1747436 VR X Cu -178.8039 D10 X D50 + 311.7034 (DSO )3, (1) where P20 = percolation rate, inches per hour at 20° C; correction factors for other temperatures are given in the text, VR = void ratio, dimensionless, D10 = effective size (diameter in millimeters of the 10-percent-finer grain size), Cu = coefficient of uniformity (ratio of the diameter of the 60-percent-finer grain size over D10), D50 = average size (diameter in millimeters of the 50-percent-finer grain size), and In = natural logarithm (log to the base e). The prediction equation for percolation rate is rather complicated, so for practical use a nomograph that simplifies the solution of the prediction equation was developed.

Jan 1, 1967

By Robert C. Ellman

Stockpiles containing 2.3 million tons of lignite constructed in the period 1948-56 in conjunction with the construction of Garrison Dam on the Missouri River demonstrate successful stable long-term storage of lignite. Uniform and thorough compaction of each of the I-foot-thick layers by which the piles were constructed produced a bulk density of 70 Ib/cu ft. Air penetration into the stockpiles was restricted to a degree that prevents spontaneous heating or deterioration of the stored lignite, A continuing record of observations beginning with stockpiling operations in 1948 has been accumulated, This includes periodic fuel analysis, analysis of pile gases, and measurement of pile temperatures on the first large stock-pile, pile 5. This report describes the stockpiling method, the changes in heating value, pile gas composition, and pile temperature and summarizes observations from 1953 to 1964, Data accumulated attest to the stability of the stored lignite. The variation of the average heating value of periodic pile-depth samples is only 160 Btu/lb (11,990 to 11,830) on the moisture" and ash-free (maf) basis during almost 10 years of storage. Temperature levels of the pile interior are progressively decreasing. At pile surface, cyclic variations occur with the season. The only problem encountered with the large stockpiles is wind and water erosion of the pile surface. The partially successful control measures used are described.

Jan 1, 1967

By O. C. Baptist

The gravitational pressure gradient (GPG) in porous sandstone containing free gas was determined to define the proper GPG to use when calculating the rate of downdip flow of oil in the Sub-Scalez No, 1 sand, Elk Hills field, Naval Petroleum Reserve 1. The GPG was determined at several gas saturations using long, artificially consolidated sandstone models that were mounted vertically in some tests and horizontally, with rotation, in others. Also determined by laboratory and field tests were relative permeabilities, capillary pressure relations; critical gas saturation, water sensitivity, and depletion drive performance. The critical gas saturation in the models having an absolute permeability of 1 to 2 darcys was about 2 percent of pore volume. The GPG with the critcal gas saturation was that due to the weight of the gas-saturated oil. The GPG in the upper part of the models was reduced as gas saturation increased to a value considerably larger than the critical. The exact gas saturation at which the GPG became less than that due to the weight of the oil could not be determined but was estimated to be of the order of 10 percent of pore volume. Tests indicate that the rate of oil production is not permanently reduced by exposure of the sand to fresh water but that the rate of injection of fresh water will be considerably less than that to brine, Methods for determining the factors mentioned above are discussed.

Jan 1, 1967