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By A. G. Starliper

The report covers studies by the Bureau of Mines on the removal of metallic values in two waste products from the Longhorn tin smelter at Texas City, Tex. One product was a slag that contained tin, tungsten, iron, tantalum, and columbium. The other product was a spent acid solution that contained tin, tungsten, iron, lead, copper, zinc, and silver and that came from presmelting treatment of impure tin concentrates. Molten slag was treated with sulfur or sulfur compounds and with coke, calcium carbide, or gaseous reductants to form tin sulfide that volatilized from the charge and to reduce tungsten along with iron and silicon to form a carbon-bearing metallic layer. The metallic layer was treated by an oxidizing alkali roast and then was water-leached to extract the tungsten. The waste acid was used in other experiments to dissolve an iron-tin- tungsten alloy (hardhead) obtained by direct reduction of the slag. An insoluble fraction containing tungsten, silver, silicon, columbium, and tantalum was removed, and copper was cemented on metallic iron, Tin was recovered by cementation on zinc plates, and lead was precipitated by adding sulfate ion. Iron was precipitated by increasing the pH which left a solution containing principally zinc. Slabs of hardhead were electrolyzed in an electrolyte consisting of waste acid to plate out groups of metals at different pH?s. The time did not permit thorough exploration of this method of treatment.

Jan 1, 1962

By R. W. Lewis

Spectrochemical procedures were developed using dc arc excitation for the determination, in parts per million, of 18 impurity elements in electrorefined beryllium and high-purity beryllium oxide. The metal samples were dissolved in dilute hydrochloric acid, evaporated to dryness, and converted to the oxide in a muffle furnace at 900° C. Germanium oxide was added as an internal standard for the determination of 15 of the elements, copper oxide for boron and molybdenum, and neodymium oxide for calcium. The average coefficient of variation was 11 percent with the exception of copper, which averaged about 43 percent.

Jan 1, 1962

By P. S. Jacobsen

In 1960 over 93 percent of the coal cleaned mechanically in the United States was cleaned in processes that utilized water or dense-medium suspensions of fine solids in water. Thus, in the process of removing deleterious ash-forming and sulfur-bearing minerals, another deleterious substance--water-- is added to the coal. The subsequent removal of the water from the coal, and the concomitant recovery of the coal from the water, is not troublesome in the sizes coarser than 1/4-inch. In the finer sizes, however, it is a difficult procedure that often costs more than the original washing operation. Because of the importance of liquid-solids separation in coal preparation, the Bureau of Mines has a continuing program of research in this field. The objective is to make available information on the performance characteristics of various types of equipment available for liquid-solids separations, thus promoting the wise selection of equipment for specific applications, and, thereby, more effective processing of coal. Results of work on flocculation as an aid to filtration5 and the sieve bend screen6 have been published. The present investigation of the screw-type classifier operating in combination with the cyclone was undertaken primarily because such classifiers are comparatively new to coal preparation and information on their performance is not available. The cyclone has become well-known since its introduction in this country by the Bureau of Mines in 1948.7 Use of the cyclone in conjunction with the screw-type classifier represents an attempt to provide the maximum recovery of solids at minimum moisture content.

Jan 1, 1962

By Leonard Obert

Between 1927 and 1957, sodium borate minerals were mined by underground methods in the Kramer District, Kern County, Calif. In 1957, surface mining methods were initiated, and during the next two or more decades it is probable that most of the production from the district will be obtained from open pits. However, part of this borate deposit is sufficiently deep that surface mining may not be economical and, hence, at some future date underground methods may again be employed. This report was prepared to document the underground mining methods employed in the district before 1957. The general geology of the district and the detailed geology of each of four mine sites are presented, together with a mineral and mechanical description of the ore and enveloping rock. The report also describes the stoping, extraction, pillar support, methods of artificial support, and other factors that affect the structural characteristics of these mines.

Jan 1, 1962

By J. D. Brown

The electron optics, vacuum system, and sample stage assembly for the Bureau of Mines? electron probe X-ray spectrograph were purchased. Four scanning curved-crystal spectrometers, two reflection- and two transmission-type, were designed and constructed by the authors. The reflection spectrometers are placed in a vacuum chamber for measurement of long-wave-length X-radiation. Detection, pulse-amplitude discrimination, and recording circuits are provided for the simultaneous measurement of four X-ray spectral lines. Minimum spot size is approximately 2 microns in diameter at 30 kilovolts and a sample-to-ground current of 5 x 10-8 ampere. At this voltage and current the limit of detection with reflection spectrometers is less than 0.05 weight-percent for most elements. The limit of detection for elements determined by transmission-type spectrometers, evaluated at 35 kilovolts and 5 x 10-8 ampere, is approximately 0.1 weight--percent for all elements having excitation voltages below 20 kilovolts. In general, reflection spectrometers exhibited satisfactory but poorer resolution than the transmission type, resolution of the spectrometers being limited primarily by crystal imperfections, with greater mosaic structure being introduced by the grinding process for the reflection crystals. Several applications of the electron probe X-ray spectrograph are described. Analysis of a uranium-steel is discussed in detail to illustrate calculation of composition from measured X-ray intensities.

Jan 1, 1962

By Michael G. Zabetakis

The autoignition temperatures (A.I.T.'s) of natural and synthetic lubricants in air were generally found to decrease with increasing pressure. Of the two types of fluids, synthetic and natural, studied in some detail, the phosphate esters had higher A.I.T.'s at any pressure between 1 and 200 atmospheres than the mineral oils. Most of the A.I.T. data obtained in this study obeyed the relationship predicted by Semenov's theory of ignition.

Jan 1, 1962

By F. E. Brantley

Blister copper was successfully deoxidized with any of a variety of reducing gases; lancing techniques or a vertical-column furnace were used to contact the copper and gases. Of the gases tested, butane, when used to lance molten copper at about 1,200° C, reaction temperature, was slightly more effective than propane, natural gas, carbon monoxide, or reformed gas for deoxidizing copper from about 1.0 to less than 0.1 percent oxygen content, Laboratory-scale tests revealed that the vertical furnace, composed of a heated column packed with silicon carbide chips or hollow carbon cylinders, was significantly faster and more efficient than the lancing technique for deoxidizing molten copper with any of the gases tested. Comparison of the gaseous-reduction method with the conventional poling method suggests that the gaseous method has important technical and economic advantages for deoxidizing blister copper to any readily controlled amount of residual oxygen content.

Jan 1, 1962

By K. E. Tame

The Bureau of Mines is studying possible modifications in conventional ore-processing methods that will confine and permit controlled disposal of radioactive liquid wastes. Stream and ground water pollution from radio-active nuclides, principally radium 226 and thorium 230, in liquid wastes from uranium mills can be minimized by reusing the waste solution within the mill. Such reuse of waste solution in an acid leach-resin-in-pulp flowsheet was investigated in the laboratory. The process consists of acid leaching for dissolution of the uranium, sand-slime separation and countercurrent decantation washing for recovery of a pregnant slime slurry, and the use of ion-exchange resin for recovery of uranium from the slurry. Reuse of clarified barren effluent for washing in the simulated mill circuit was carried through 55 cycles. Dissolution of uranium from the ore averaged 97.5 percent. Washing efficiency of 99.9 percent was attained when using 4.35 volume tons4 of combined barren effluent and makeup water per ton of ore. Absorption of uranium from the pregnant slime slurry by an ion-exchange resin averaged over 99.9 percent.

Jan 1, 1962

By William J. Campbell

Evaluation by the Bureau of Mines of published expansion values for magnesium oxide shows significant variation in values, which may be attributed to sample variables, experimental errors, or systematic differences between measuring techniques. To eliminate the sample variable in measuring expansion, thermal expansion characteristics of a high-purity polycrystalline magnesium oxide were determined by 21 cooperating laboratories using one or more of the following techniques; X-ray camera, X-ray diffractometer, dilatometer, interferometer, and telemicroscope. All expansion values were corrected by the author to a single reference temperature of 25° C. Linear expansion was expressed as a power series in the form of the following equation. Expansion (percent) = [[ A + B (?t) + C (?t)2] ?t 104] The constants, A, B, and C, were determined by least square techniques for X-ray camera, X-ray diffractometer, and dilatometer data separately, and for combined data of all five techniques. Expansion values are tabulated from 26° C. to 1,400° C. in 2° C. intervals using constants derived from X-ray camera data. Below approximately 500° C., expansion values obtained by dilatometric and interferometric methods are significantly lower than those by X-ray methods; above 500° C., this bias decreases rapidly. Comparison of results within methods showed the least variance for X-ray camera results; dilatometer and X-ray diffractometer results have about the same variance. The average deviations, in percent, between observed and calculated expansion values among methods were approximately 10 percent from 100°C. to 300°C., 5 percent from 300°C. to 500°C., and 2 percent from 500°C. to 1,400°C. Maximum deviations were approximately twice as large in most instances.

Jan 1, 1962

By D. F. Walsh

A study of damping capacity was made on a number of magnesium-base alloys, commercial types and experimental compositions. Hardness and tensile properties were determined, and the microstructure of each alloy was examined. Alloys of low yield strength, in general, possessed high damping ability. A correlation was established between damping capacity and composition.

Jan 1, 1962

By L. F. Willmott

Pulverized high-volatile A bituminous coal was gasified with oxygen and superheated steam in a pressure-gasification pilot plant equipped for slurry feeding. The minimum ratio of water to pulverized coal that could be pumped satisfactorily as a slurry was about 1 to 1. Heating this slurry produced a suspension of coal in superheated steam having a steam-to-coal ratio greater than the 0.3 to 1 proportion that is considered optimum for pressure gasification of pulverized coal. A steam separator removed enough steam to provide ratios down to about 0.5 to 1, but a 0.3 to 1 ratio was not achieved. Gasification of Sewickley coal produced a synthesis gas containing about 36 percent H2, 46 percent CO, and 13 percent CO2, Gas output, gas composition, and coal and oxygen requirements were Virtually the same as for a pilot plant equipped for fluidized-coal feeding. Typical results from the slurry-fed plant at 300 psig were carbon gasified, 95 percent; coal requirement, 34 lb/M (thousand) std cu ft CO + H2 produced; oxygen requirement, 365 std cu ft/M std cu ft CO + H2 produced. The results showed that the two feeding methods are equally satisfactory from the standpoint of gasification. A choice between a fluidized-coal gasification process or a slurry gasification process depends on considerations relating to the coal-feeding phase itself, including capital and operating costs, manpower requirements, safety, and flexibility of operation.

Jan 1, 1962

By Robert Hall

The Lynch Creek beryllium-tungsten prospect was investigated as part of the domestic beryllium resource studies by the Bureau of Mines. This prospect is in the Birch Creek mining district, Lander County, Nev., 9 airline miles south of Austin. A tungsten mine was operated intermittently from 1952 to 1957. Beryl was identified in the pegmatite dikes in 1960, and the lode claims were relocated. No beryl has been produced. Rocks in the area are Paleozoic sediments2 cut by pegmatite and aplite dikes and quartz stringers. Beryl occurs in random pockets, as disseminations throughout the dikes, and in occasional pockets in the quartz stringers.

Jan 1, 1962

By Kenneth M. Earl

This report describes the results of a field study conducted by the Bureau of Mines during 1956 and 1957 on manganese-and iron-bearing mineral deposits in the southern district of Aroostook County, Maine. The work was undertaken to determine the extent of deposits largely concealed under glacial drift and to obtain subsurface samples for manganese mineral identification and research in ore dressing and extractive metallurgy. The investigation was confined to the Westford Hill-Daggett Hill area in Hodgdon Township and to the Stewart prospects and vicinity in Linneus Township. Over 50 magnetic anomalies were mapped by magnetometric surveys in the Westford Hill-Daggett Hill area, Hodgdon Township. The largest anomaly, as outlined by the 1,000-gamma contour, indicates a deposit 3,200 feet long with a maximum width of 350 feet. The smallest anomaly measures about 10 feet wide by 25 feet long.

Jan 1, 1962

By F. B. Petermann

The Bureau of Mines conducted electric furnace smelting tests on sintered flotation concentrate and siliceous log-washed are. The flotation concentrate was derived from the Maggie Canyon deposit of the Artillery Mountains area, Mohave County, Ariz., and contained, before sintering, 35.6 percent Mil and 19.4 percent Si02 + A1203. The log-washed ore was from the McGregor deposit of the Artillery Mountains area, Mohave County, Ariz., and contained 31.2 to 33.6 percent Mil, 19.5 to 27.6 percent Si02 + A1203, and 2.5 percent Pb. This work was undertaken to determine the most effective smelting technique for producing standard products from such nonspecification ore and concentrates. The objective was to collect data, using a small furnace, which would be reasonably accurate and permit extrapolation to large-scale practice for comparing with results on specification-grade are.

Jan 1, 1962

By G. V. Sullivan

This report summarizes the results of a preliminary study concerning manganese extraction from low-grade dolomitic materials from the Philipsburg district in Montana by the Dean-Leute ammonium carbamate process. Studies were made to determine the relationship between the variables involved in treating these materials by a roast-leach process and the amount of manganese extracted. The variables studied were the roast temperature, the roast particle size, the molar ratio of NH3 to CO2 in the leach solution, the liquid-solid ratio in leaching, the leach time, and the size of the particles being leached. The roast-leach studies were statistically designed, and the experimental results were evaluated by an analysis of variance.

Jan 1, 1962

By A. A. Cochran

Methods of preparing small heats of steel containing radioisotopes were developed, and the techniques of stripping film autoradiography were used to detect and study the carbide and sulfide phases in titanium-bearing steels. Metallography had revealed areas of titanium sulfide and ferrite or pearlite adjacent to areas of titanium carbide and ferrite, and unidentified, irregular phases at the boundaries between these two areas. Sulfur 35 was used to deter-mine the extent of the titanium sulfide inclusions, and carbon 14 was used to delineate the titanium carbide phase. Individual radioactive areas were located with a resolution of approximately 10 microns. A general background exposure that was not correlated with microscopically visible phases was observed in the carbon 14 autoradiographs. The evidence from both sulfur 35 autoradiographs and carbon 14 autoradiographs indicated that the unidentified inclusions were sulfides rather than carbides. INTRODUCTION The use of radioisotopes to facilitate the work at the Rolla Metallurgy Research Center was expanded in fiscal year 1959 when the Bureau of Mines authorized the installation of an intermediate-level radioactivity laboratory. Before this time, sealed cobalt 60 sources had been employed for radiography, but no tracer work was done. The primary objective of the first experiments conducted in the new laboratory was to supplement physical metallurgy investigations of selected problems in steel research.

Jan 1, 1962

By R. E. Perry

To develop new or improved flotation methods for beneficiating low-grade red iron ores, the Bureau made many bench scale and continuous anionic flotation tests on ferruginous sandstones and calcareous iron ores from the north-eastern part of the Birmingham, Ala., iron district. The ores contained about 21 to 36 percent iron, a to 11 percent lime, and 22 to 64 percent silica. Production of iron concentrates containing 48 to 52 percent iron was technically feasible in batch tests, and the iron recoveries ranged from 85 to 92 percent. In continuous tests 49 to 51 percent iron products were obtained with 80 to 90 percent recovery.

Jan 1, 1962

By Richard D. Graves

Pitch from low-temperature carbonization of bituminous coal was hydrogenated at cracking conditions in a continuous bench-scale unit to produce low-molecular-weight oils and tar acids. The pitch contained 15.6 pct benzene-insoluble material, 4.0 pct hexane-soluble oil, and 80.4 pct asphaltene by weight. At 475° C, 7,500 psig, and 1.5 hours residence time, hydrogenation products, based on the weight of pitch, were about 36 pct oil boiling below 325° C, 24 pct hexane-soluble heavy oil, 17 pct asphaltene, 1 pct benzene insolubles, and 12 pct hydrocarbon gases. The yield of tar acids boiling below 250° C was 4.3 pct, and the yields of C6 to C8 paraffins, naphthenes, and aromatics were each less than 1.0 pct. The yield of tar acids was within the range of yields obtained by hydrogenation or high-temperature carbonization of bituminous coal (2 to 5 wt pct). Yields of oil boiling below 325° C increased with increased residence time or temperature. There was little or no effect of residence time on yields of alkali- soluble material which contained tar acids. Yields of hydro-carbon gases increased markedly with an increase in temperature from 475° to 500° C. Lowering the hydrogen pressure to 4,500 psig resulted in yields similar to those obtained at 7,500 psig.

Jan 1, 1962

By Raymond W. Hiteshue

To aid in designing a continuous system for evaluating processes for converting coal to high-Btu gas] the Bureau of Mines determined the amenability of various coals and a char to hydrogasification at 800° C and 6,000 psig using a molybdenum catalyst. A lignite from Rockdale, Tex., an hvCb coal from Rock Springs, Wyo., a char from the low-temperature carbonization of the latter, an hvAb coal from Pittsburgh, Pa., and an anthracite from Luzerne County, Pa., were selected. Highest yields of gaseous hydrocarbons, 94 pet, based on maf feed, were produced from char, and lowest yields, 67 pct, were obtained from lignite. Hydrocarbon gases contained 82 to 92 pct methane, 8 to 15 pct ethane; and 1 to 3 pct propane.

Jan 1, 1962

By A. J. Forney

The hot-gas-recycle process, for the hydrogenation of carbon monoxide, was investigated in a 12-inch-diameter reactor. Initially because the distribution of gas was poor, hotspots developed in the catalyst bed. After the velocity profile of the gas flowing through the bed was studied, the method of packing the catalyst was altered. Because this change improved the distribution of gas, temperature control was excellent. The l2-inch-diameter reactor was operated successfully in the synthesis of gaseous and liquid fuels. When high-Btu gas was synthesized in two stages, parallel-plate assemblies of Raney nickel were almost as active as granular Raney nickel in the second reactor. The pressure drop through the second reactor, however, was reduced 90 percent by the use of these assemblies.

Jan 1, 1962