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By E. C. Pattee

A mobile spectroscopic laboratory was completed by the Bureau of Mines in 195 to provide a rapid, inexpensive means of field testing samples for beryl¬lium and other associated metals of possible commercial importance. Spectro-copes have been used in laboratories for many years in various types of research and routine analyses, but this spectroscope is probably the first mobile unit. The laboratory provides for spectroscopic, radioactivity, fluorescent, and limited chemical tests of samples. The unit has been a valuable reconnaissance tool. It has been used to search for beryllium, cesium, columbium, tantalum, rubidium, and lithium in Idaho, Washington, and Montana. Several very low grade deposits of these elements were found, and occurrences of other important elements were identified; however, none are of economic importance. The spectroscope permits the detection of elements by analysis of visible light produced when elements in a small powdered sample are volatilized in an electric arc., A total of 70 elements can be detected; 29 can be detected at or below 0.01 percent, Electric power for the arc is supplied by a gasoline motor-driven generator, Equipment is housed in an aluminum van, mounted on a 4-wheel-drive vehicle for easy maneuverability on mountain roads, A trailer with crushing, pulverizing, and splitting equipment permits the reduction of samples to a small representative pulp.

Jan 1, 1963

By B. K. Shibler

A highly flexible laboratory-scale fluidized-bed reactor was designed, constructed, and successfully operated continuously at temperatures up to 1,300° C during an investigation of thermal methods for decomposing gypsum. This report discusses briefly the many problems encountered in developing the 10-inch-diameter reactor and describes its design and construction in sufficient detail to enable other research organizations to build a comparable unit. The reactor consists of a 10-inch-inside-diameter vertical tube which can be varied from 6 to 10 feet high; it is formed from 2-and 3-foot sections of silicon carbide pipe. The tube is surrounded by a 3-inch heating space formed by an outer 4.5-inch-thick circular wall of insulating firebrick. A cone-shaped fluidizing chamber is bolted to the bottom of the reactor. Fluidizing gas enters through the bottom of the cone, and ore is introduced by means of a screw feeder connected to an inlet located just above the gas port. A silicon carbide overflow tube of 1.25-inch inside diameter extends upward into the reactor. The depth of the bed is controlled by substituting different lengths of overflow tube. Twin dust-recovery systems, each composed of a cyclone and Fiberglas filter, are attached to two gas outlets at the top of the reactor tube. The reactor is designed for research on both exothermic and highly endothermic reactions. It can be fired externally by means of four natural gas burners that jet tangentially into the annular space at the base of the reactor. Alternatively, it can be fired internally, using a mixture of air or oxygen and natural gas as the fluidizing medium. A separate instrument panel contains flowmeters, manometers, an automatic program controller, and a multiple-point recorder for printing a record of the temperatures measured by thermocouples located at critical points in the reactor.

Jan 1, 1963

By Frank Parrish

History and performance data of 17 water-injection projects in Cooke and Grayson Counties in north Texas are presented for the purpose of studying and comparing operating practices and oil-recovery techniques. Water is injected into Strawn and Canyon sands of Pennsylvanian age. The principal formation flooded is the Strawn, which ranges in depth from 725 to 6,900 ft in the projects covered. Estimated ultimate recoveries range as follows: Primary, 22 to 494 bbl per acre ft; and secondary; 63 to 296 bbl per acre ft. These figures represent the following percentages of original oil in place: Primary, 10 to 46 pct; and secondary, 8 to 23 pct. Shallower projects; 725 to 1,500 ft in depth, had higher average primary and secondary recoveries than did deeper projects. Crude-oil gravity, which ranges from 20° to 45° API, was not relatable to yield of secondary recovery oil. Analysis of the data indicates that five-spot injection patterns will yield the highest percentage of oil remaining at start of flooding; that is, 28.8 pct for five-spot injection patterns, compared with 20.8 pct for line-drive patterns and 11.6 pct for random patterns. Waterflooding in this area appears to be very successful. Secondary recoveries of most projects are expected to nearly equal primary recoveries.

Jan 1, 1963

By Hal J. Kelly

A number of problems that developed in processing the halloysitic clays of eastern Washington and northern Idaho were investigated by the Bureau of Mines. The deflocculating effect of tetra sodium pyrophosphate is compared with several other compounds, and on the basis of current theory, the advantage of sodium pyrophosphate as a deflocculating agent is explained. The adsorption of the sodium ion by clay in a clay"-water system was established by a radioactive tracer technique, and the deflocculating action of sodium pyro- phosphate was postulated. The effective dispersion of the halloysitic clays was limited by the occurrence of tightly bound aggregates of small, individual crystals. Disaggregation of the agglomerates was investigated by liquid extrusion and ball milling of dilute slurries and by extrusion of the clay in a plastic state. The greatest increase in the production of small particles was by high? pressure liquid extrusion.

Jan 1, 1963

By F. D. Stevenson

A metal diaphragm pressure relay system was constructed to measure vapor pressures of the metal halides, oxyhalides, and other substances at temperatures up to 700° or 800° C. The vapor pressure of arsenic (III) oxide (As2O3) was determined to verify the reliability of the apparatus for such measurements. The data for the liquid AS2 Os (2820 to 4830 C) are represented by the equation, log Pmm = 6.875 - 2,929/T, from which the normal boiling point was calculated to be 461° C. The heat of vaporization calculated from this equation was 13.40 ±0.09 kcal/g mole As4OS and is essentially constant over the interval studied. The melting point of the octahedral arsenic (III) oxide was determined to be 278° C from the inter-section of the solid and liquid vapor pressure curves, A thermal analysis apparatus is also described by which melting and transition temperatures could be checked by a method independent of vapor pressure data. The melting points of the monoclinic and octahedral forms were determined to be 314.4 ±1.4° C and 278 ±5° C, respectively.

Jan 1, 1963

By P. A. Bloom

Bureau of Mines research was conducted to develop effective separation methods that might be used in exploiting substantial tonnages of complex barite-fluorspar ores in Arizona. The exploitable reserves now may be increased as recent batch and continuous flotation tests demonstrated that a complex barite?-fluorspar ore from the Red Chief deposit, Yuma County, Ariz., could be selectively treated to concurrently produce (1) fluorspar and (2) a barite byproduct of marketable grade. The sample contained 24.8 percent CaF2 and 24.3 percent BaS04. Processing comprised production of a fluorspar product containing 97 percent CaF2 with an 82 percent recovery, using a sodium fluoride-lignin sulfonate-fatty acid reagent combination. Concurrent retreatment of the fluorspar tailing, using sodium cetyl sulfate as a collector, yielded a barite product of 94 percent BaS04 grade with a 71-percent recovery. The products met specifications for acid-grade fluorspar and drilling mud-type barite.

Jan 1, 1963

By W. A. McKinney

Bureau of Mines Research has demonstrated that it is technically feasible to segregate oxidized copper ores by use of a direct-fired, refractory-lined rotary kiln. Previously, the segregation process had been effected only in much more complicated indirect-fired, stainless steel kilns, The method comprises heating crushed ore premixed with small quantities of salt and carbonaceous material, such as coke, to about 830° C to produce copper as fine flake and metallic films on the surface of the coke particles. After grinding of the cooled furnace calcines, the copper is recovered by conventional flotation. During direct-fired segregation it was necessary to closely control the air-gas mixture in the burner. Good copper recoveries were obtained only when adding air in the limited range of 1.15 to 1.2 times the theoretical amount required for combustion of the natural gas. Batch trials of the new technique on quartzite-, limestone-, sandstone-, and limonite-type oxidized copper ores containing from 1.4 to 6.2 percent copper yielded flotation concentrates containing from 3.7 to 45 percent copper, representing 84 to 95 percent recoveries. Analyses of the furnace gases showed that loss of copper by volatilization was negligible. The preliminary direct-firing segregation studies were complemented by continuous runs on the quartzite ore, containing 1.4 percent copper, in an integrated segregation-flotation pilot plant having a 60 pound-per-hour capacity. In a typical test, 84 percent of the copper was recovered in a cleaner flotation product containing 25 percent copper. The study will be continued to further delineate the conditions for good segregation as effective use of standard ceramic-lined kilns will render the process more attractive from a commercial standpoint.

Jan 1, 1963

By Scott W. Hazen

This Bureau of Mines report presents the results of a study and statistical analysis of part of the initial exploration churn-drill sampling and some of the subsequent underground diamond-drill-core sampling in the North are body at the San Manuel copper mine, Arizona. These data were derived from regular exploration and mine sampling, not from special samples obtained solely for statistical analysis. The study was conducted as part of the Bureau's continuing program on sampling-methods research. The major objective of the study was to investigate the feasibility of using the techniques of statistical analysis in evaluating sample and assay data and computing grade and tonnage of Ore from porphyry-type copper deposits. It was recognized that using existing data acquired over a period of several years by different methods would introduce problems and limitations for precise comparisons. However, it was expected that the study would provide some general conclusions and certainly a number of preliminary conclusions on the nature of the mineral characteristics and their effect on sampling procedures, the requirements for sampling deposits of this type, and the comparative results of churn-and diamond-drill sampling in the same area of the deposit. All of this information would be essential for future sampling-methods research for computing grade and tonnage of ore.

Jan 1, 1963

By John J. Mulligan

The Bureau of Mines investigated coal deposits at Mount Gran (latitude 76°59' S, longitude 161°07' E), Victoria Land, Antarctica, during the austral summer of 1959-60 as part of the continuing U.S. Antarctic Research Program, which is under the auspices of the National Science Foundation. The coals and associated rocks were measured, sampled, and analyzed. Five coalbeds, ranging in thickness from over 10 feet to scattered fragments of coaly material in sandstone, occur in a sandstone-coal series overlying a series of crossbedded red-buff sandstones. Both series are part of the Beacon group of sediments, and both show some evidence of pressure metamorphism. The sandstones are poorly cemented and are composed dominantly of rounded and often frosted quartz grains. The sediments have been broken and uplifted by a series of massive diabase sills. The broken nature of the sediments precluded an estimate of the amount of coal present. The Mount Gran coals are highly attrital banded anthracites and semianthracites that have most commonly a moderately dull luster but do include bright bands. Coal in contact with or near diabase intrusives is partly graphitic but shows no evidence of coking. Apparently the coal was beyond coking rank before emplacement of the adjacent intrusives. Fragments of the plant Glossopteris indica found with the coal suggest Permian age but do not prove it. The coals appear to be derived from plant remains that collected in shallow basins; individual coalbeds would tend to be lenticular bodies that formed in different places as the dominantly sandy sediments were deposited. The wide distribution of coal indicates that coal-forming conditions prevailed over much of the continent; the great thickness of Beacon sediments indicates that similar conditions may have persisted through a long period of geologic time. Generally similar coal deposits may occupy widely separated stratigraphic positions.

Jan 1, 1963

By R. S. McClain

Continuous-circuit flotation and batch-scale precipitation tests were made by the Bureau of Nines to determine rejection of carbon and recovery of fluorine and aluminum compounds from aluminum reduction plant residues, About 40 to 60 pounds each of aluminum fluoride and cryolite are lost for each ton of aluminum produced. Gasoline and turpentine were satisfactory for floating carbon from both fresh water and saturated solution systems. Soluble fluorine and aluminum compounds were recovered by precipitation with sodium aluminate and carbon dioxide. Over 99 percent of the carbon was removed by flotation. Fluorine and aluminum recoveries up to 77 and 63 percent, respectively, were obtained in a combined precipitate and nonfloat product, In the fresh water system the combined product was mostly cryolite with some gibbsite. In the saturated solution system the product was mostly sodium fluoride, some cryolite, and minor amounts of gibbsite.

Jan 1, 1963

By F. B. Petermann

Two-stage electric smelting tests, using small submerged arc furnaces, were made on high-iron manganiferous materials from the Pioche District, Nev., and the Cuyuna Range, Minn. The object was to reduce sufficient iron in the first stage to give a slag with a favorable Mn to Fe ratio for smelting to ferromanganese in the second stage. The nodulized flotation concentrate from the Pioche District contained 29.2 percent Mn and had a Mn to Fe ratio of 2.3:l. When smelted with coke and silica or alumina as flux, more than 90 percent of the manganese was recovered in slags with Mn to Fe ratios of 10: :24:1. The Pioche slag was smelted to ferromanganese using coke and lime- stone or dolomite as flux. The ferromanganese was high in silicon but other- wise met specifications. Recovery of manganese to ferromanganese in this step was 73 to 78 percent. Overall recovery of manganese was about 70 percent. The sintered flotation concentrate from the Cuyuna Range material contained 12.9 percent Mn and had a Mn to Fe ratio of 0.3:1. When smelted with limestone as flux, about 83 percent of the manganese was recovered in a slag with a Mn to Fe ratio of about 6:1. The Cuyuna slag was smelted to ferromanganese with coke and limestone for flux. Recovery in this step was 61 percent of the manganese in a high silicon ferromanganese. Overall recovery of manganese was about 50 percent.

Jan 1, 1963

By D. G. Kesterke

The electrolytic reduction of uranium dioxide to molten uranium in fluoride baths at approximately 1,200° C was demonstrated. Electrolyte constituents were BaF2, UF4, and either MgF2 or LiF. Preliminary laboratory-scale experiments were made in which the uranium oxide was added continuously for 3 to 5 hours to the cell during electrolysis. Over 1,000 grams of metal of 99-8 percent purity was made in some tests, Major impurities were aluminum, barium, iron, silicon, carbon, and oxygen. The effects of cell design, geometry, and bath composition were investigated. Electrode arrangement was the most important factor in cell performance.

Jan 1, 1963

By Albert W. Deurbrouck

This report describes the preparation characteristics of the significant, presently producing coalbeds in Mercer County, W. Va. Approximately 650,000 tons of coal was produced in Mercer County, W. Va., in 1960, of which over 630,000 tons was cleaned in four preparation plants. In 1960 the Pocahontas Nos. 3, 6, and 11 coalbeds supplied 99.5 percent of the total coal mined in the county. Because the number of working mines In this county was small, only six samples were collected; four of which were of metallurgical quality as mined. The remaining two samples could be upgraded by washing at suitable specific gravities. Many of the samples taken were of metallurgical quality as mined; however, the float-and-sink analysis on these coals has been included to point out their amenability to the production of premium quality, special purpose coals. In general the coals were low-volatile bituminous in rank with low ash and sulfur contents.

Jan 1, 1963

By John L. Miller

The synthetic fluormicas may be divided on the basis of silicon content into tetrasilicic, trisilicic, and disilicic. Properties of lead and barium disilicic fluormicas were determined to characterize these two representative members of the disilicic group. Properties described include unit-cell parameters from X-ray diffraction, optical data, chemical composition, density, melting point, and mechanical and dielectric properties. Both the lead and the barium micas were typically monoclinic; neither was sufficiently cleavable to yield usable mica splittings. Both yielded polycrystalline, machinable ceramics with excellent mechanical and dielectric properties.

Jan 1, 1963

By Frank A. Peters

A series of evaluations is being made to determine the relative processing costs of producing metallurgical-grade alumina from low-grade aluminous materials. These evaluations include the estimated operating and capital costs as well as recommendations for additional research and development to improve the processes and to lower their costs. The design for each process is based on published work. The three processes considered in this evaluation are designed to leach alumina as aluminum sulfate from calcined clay with sulfuric acid and to remove the silica residue by filtration. The filtrate from leaching is then purified by one of the following methods: Removal of iron in electrolytic cells using mercury cathodes; removal of iron by chemical precipitation through the formation of an iron-manganese complex; or precipitation of the alumina from an aqueous-ethanol solution, leaving iron in solution. Both the operating and capital costs for these processes are higher than those for the Bayer process. For plants producing 1,000 tons of alumina a day, the estimated operating costs per ton of alumina are: Electrolytic iron-removal process........... $81.35 Chemical iron-.removal process............... 82.08 Ethanol purification process............... 86.17 The investment in mercury is not part of the operating cost since this cost is considered equivalent to catalyst cost which would not be shown. The estimated capital investments for 1,000- ton-per- day plants on a Marshall and Stevens chemical equipment index basis of 240.0 are: Electrolytic iron-removal process...... $116,775,500 Chemical iron-removal process............... 99,418,900 Ethanol purification process................ 94,210,200 These investments include the working capital but not the land for each of the processes. Included in the electrolytic iron-removal process is an investment of $4,859,400 for mercury. Investigation of other methods for removing iron, of the decomposition operation, and of the leaching operation could reduce these costs.

Jan 1, 1963

By Robert M. Doerr

Isothermal oxidation kinetics were determined for three grades of Ni and for 99.99 percent Co in Ca and in air from 800° to 1,200° C. The oxidation reactions followed approximately the parabolic rate law. For 99.99 percent Ni in 02 at 1,200° C, the parabolic rate constant was 2 mg cm-2 hr-2. For 99.99 percent Co in dry air, the constant ranged from 1 mg cm-2 hr-2 at 800° C to 18 mg cm-2 hr-2 at 1,200° C; for 99.99 percent Co in 02 the constant was 2 mg cm -2 hr-2 at 800° C and 10 mg cm-2 hr-2 at 1,000° C. For 99 percent Ni in dry air, the constant ranged from 0.2 mg cm 2 hr-2 at 800° C to 3 mg cm 2 hr-2 at 1,200° C. By X-ray diffraction measurements, only divalent oxides were found in the scales. Volumetric and quartz-helix gravimetric methods were used. The volumetric apparatus was designed to permit less stringent restrictions on the corrosion specimens; it was also more convenient to use. The agreement between the weight gain determined gravimetrically and the 02 consumption determined volumetrically was not good enough for direct comparison of gravimetric and volumetric results.

Jan 1, 1963

By S. J. Hussey

This Bureau of Mines report presents a discussion of the statistical approach to the design of experiments and indicates, by concrete examples, how and when statistical design is essential for obtaining meaningful data with a minimum number of experiments. Every research worker plans his work and designs his experiments in a manner which, based on his experience, seems most rational to him and which he believes will produce the information essential for resolving the problems. If the results obtained are open to multiple interpretations and are not of definitive reliability, the failure of the experiment design to produce the desired information may be due to several causes, These include faulty judgment in selecting the factors to be tested, ignoring the importance of interaction between factors, failure to adequately control test variables, and assuming that meaningful trends in the results can be identified without comparison to a predetermined experimental error. An experienced researcher probably will deduce from the nature of the data obtained that the design is faulty and may by trial and error ultimately arrive at the correct solution to the problem. Statistical methods of planning research minimize the chance of faulty experiment design, embody concrete procedures for testing the validity and reliability of the test data and for indicating mandatory changes in the design, and enable the researcher to obtain meaningful information with the least number of tests.

Jan 1, 1963

By R. D. Berkenkotter

Titanium and iron assays obtained from cores of three diamond-drill holes from the Cebolla Creek titaniferous iron deposit were evaluated by statistical techniques to obtain information concerning the mineral characteristics of the deposit and to make a preliminary determination of sampling requirements for the deposit. A range of sample volumes representing sizes from one-sixth NX core 2 feet in length through full NX core 10 feet in length were prepared by split-ting the NX core with a diamond saw and combining pulverized splits. Results indicate the existence of at least two statistical populations having different average grades of iron and titanium. Each has an assay frequency distribution that is not normal but is highly peaked (leptokurtic). Frequency distributions of assays from specific altered zones of the drill holes appear to be normally distributed. Increasing the cross-sectional area of the sample unit to change assay volume did not result in significant changes either in assay values or the resulting frequency distributions of assays. However, when assay volume is increased by increasing sample interval, the shape of the assay frequency distribution changes, and a normal distribution of assays is approached. Positive correlation exists between titanium and iron assays. The degree of correlation, although very significant, is too low to use for prediction purposes. Although the amount of data from three widely separated drill holes is not sufficient to establish an average grade for this large deposit, it indicates a range of expected assay values and provides some information for determining requirements of future sampling for evaluation purposes.

Jan 1, 1963

By Robert C. Johnson

Water-swelling fluormicas and fluormontmorillonoids were synthesized and described. They were found predominantly in the system Mg0 - MgF2 - Si02, with varying amounts of Li+ or Na+, Some water-swelling synthetic minerals were prepared with only strontium or lead in the twelvefold position, Water- swelling compounds containing either K+ or Ba+ were not found. The synthesized water-swelling products were shown by electron microscopy, X-ray diffraction, and chemical analysis to be typically two-silica-layer, platy compounds, Except for the complete substitution of fluoride for hydroxyl, the compounds were similar to the natural micas or montmorillonites. The stability and properties of the compounds were further established by electrodialysis, by differential thermal analysis, and by anion and cation exchange methods. Fluoride in the interlayer positions was nonexchangeable except through decomposition of the product. Exchanging the sodium or the lithium of the synthetic fluormicas or fluormontmorillonoids with potassium ion, particularly those derived from KOH provided a product from which a completely inorganic paper of extraordinary flexibility was fabricated. This paper had excellent mechanical and electrical properties except for water adsorption and a high power factor. Neither of these problems was solved during this investigation. However, papers with dielectric strength from 1,500 to 5,000 volts per mil were readily fabricated, particularly from the lithium containing fluormicas or fluormontmorill onoids.

Jan 1, 1963

By Carl Rampacek

The conversion of dilute sulfur dioxide gas into sulfuric acid by autoxidation in mechanical cells of the flotation or gas absorber types was investigated. Bench-scale tests were made with sulfur dioxide-air mixtures to determine the influence of several factors on autoxidation of sulfur dioxide, using iron and manganese salts as catalysts. The laboratory investigation subsequently was extended to pilot plant acid-making tests, using a modified turbomixer gas absorber having a 12-inch-diameter impeller. Sulfur dioxide gas was produced for the tests by roasting pyrite in a fluidized-bed reactor. In the better tests, made with manganese sulfate as the catalyst, the equivalent of 1,000 pounds of anhydrous H2SO4 was produced per 24 hours as a 10-percent solution; power consumption was 0.2 kwhr per pound of equivalent anhydrous acid synthesized. The batch and continuous tests demonstrated the technical feasibility of producing dilute sulfuric acid by autoxidation of sulfur dioxide gas in mechanical cells when converting pyrite roaster or waste smelter gases.

Jan 1, 1963