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By Gerald W. Elger

The Federal Bureau of Mines developed a modification in the conventional Kroll process for preparing high - purity hafnium metal . This modification involved the partial replacement of magnesium by sodium in the batch reduction of purified hafnium tetrachloride to sponge metal . The raw tetrachloride was purified either by thermal degassing of the volatile contaminants to the atmosphere or by fused- salt treatment . In the fused- salt treatment , the tetrachloride was contacted with molten alkali chlorides to remove the impurities . The reaction byproducts were removed from the metal by heat treatment in an evacuated furnace . The metal sponge was consolidated by melting into buttons or ingots , which were analyzed for impurities . The purity of the metal prepared by the modified process is superior to that of the metal produced by the conventional method . The hafnium metal was comparable to crystal - bar hafnium except for the oxygen content , despite the abnormally high impurity concentrations in the raw tetrachloride . Several ingots were successfully cold - rolled to sheet .

Jul 1, 1960

By Lester M. Adams

In 1980, the Bureau of Mines surveyed a group of mine seals in Randolph County, WV, to evaluate their effectiveness for reducing toxic pollutants in mine water discharges. The survey focused on 11 block wet mine seals, but mine seals of several other types were also examined. The seals were installed in 1966 and 1967 in abandoned drift portals by the Federal Water Quality Administration (FWQA), a predecessor of the Environmental Protection Agency (EPA), in cooperation with the Bureau of Mines and other Federal and State agencies, in a project known as Elkins Mine Drainage Pollution Control Demonstration Project. The seals were designed to prevent air from entering the mine portals while allowing mine water to flow out. It was believed that by preventing air from entering inactive or abandoned mines, the formation of toxic pollutants and acid mine drainage (AMD) could be reduced. Evaluation of the seals was based on water flow measurements, water analyses, and visual observations. The Bureau's 1980 data were compared with past data collected by the EPA. Several leaks and failures were observed in the clay seals, as evidenced by apparent blowouts and the absence of vegetation where the mine water surfaced. Analyses of the 1980 data indicated some improvement in the quality of water discharged from many of the wet air seals.

Jan 1, 1984

By M. S. Seehra, R. S. Pandurangi

"The interaction of amorphous silica particles with several hydrogen bonding agents (H2O,, C2H,OH, C,H,NO) was investigated by monitoring the changes in the bulk and surface IR vibrational modes of silica using photoacoustic spectroscopy, It is argued that the intensity of the silanol band at 3747 cm-1 provides (an inverse) quantitative measure of the interaction of surface groups, along with the shift in the broad hydroxyl band, the interaction following the order C,H,NO > C2H2OH > H2O.The use of IR spectroscopy to study the adsorption on solid surfaces is well documented in the literature,"" For example, hydroxylation of a clean silica surface results in the formation of the free silanol group Si-OH, with a sharp IR band near 3747 cm-1. Further hydroxylation produces a broad band near 3500 cm-1, which is believed to result from various hydrogen-bonded silanol bands leading to a multilayered surface structure of few nm.3-6 Earlier studies had indicated a relationship between the surface silanol band and various chemical activities of silica such as cytotoxicity,7-9 catalysis,10-12 and others.13 Recent studies from our group14-in which the intensity of the silanol band and cytotoxicity of silica, heat-treated at various temperatures up to 1095°C, were investigated-have provided a strong correlation between cytotoxicity and intensity of the silanol band.Coating of silica by PVPNO (polyvinyl-2-pyridine N-oxide with the empirical formula C7H8N0), a strong hydrogen bonding agent, is known to reduce the cytotoxicity of silica, presumably by chemically blocking the silanol groups from phospholipids.15 This interaction of the hydrogen bonding agents with the silica can be studied by IR spectroscopy, and Knozinger16 and Rouxlet and Semples17 have used transmission IR spectroscopy to study the effect of various chemicals on the surface IR modes of silica. However, one of the major disadvantages of transmission IR spectroscopy is that the sample preparation (grinding and mixing with KBr and pelletizing) usually distorts the surface modes (see, e.g., Ref. 14) and there is always a doubt about the effect of the sample preparation on the measured properties, In recent years, photoacoustic (PA) spectroscopy has become the technique of choice for studying the IR spectra of samples in their natural state, since no sample preparation is necessary.18,19 Moreover, according to a recent paper,20 the relative intensity of the surface modes in PA spectroscopy of silica particles is much higher than that in transmission FT-IR spectroscopy. Consequently PA spectroscopy is ideal for studying the surface chemistry, In this work, we have used PA spectroscopy to investigate the interaction of three hydrogen bonding agents (C7H8NO, C2H5OH, and H20) with the silica surface by monitoring changes in the surface IR modes, Our results show that the surface IR modes get perturbed to a larger extent than the bulk IR modes in interaction with the hydrogen bonding agents, Moreover, whereas in the earlier studies, the shift of the broad silanol band near 3500 cm-1 was used as a measure of the interaction with hydrogen bonding agents,16,17 here we show that the relative decrease in the intensity of the sharp silanol band near 3747 cm-1 also serves as a quantitative parameter for the relative surface coverage and surface modification, Details of this work are given below,The Cab-O-Sil samples of silica used here were obtained from the Cabot Corporation of Tuscola, IL, In our earlier studies,14,20 we have shown these particles to be amorphous and about 0.05 am in size, For coverage of these particles with H20 and C2H50H, the following procedure was employed. About 5 mg of silica was mixed with 50 mL of the liquid (H2O or C2H5OH) and refluxed for one hour, The remaining liquid was allowed to evap¬orate to dryness and 1 mg of the treated sample was used to collect the PA spectra. In the case of PVPNO, the amount that binds to Cab-O-Sil is taken from the data on quar"

Mar 1, 1992

By V. E. Edlund

Laboratory batch flotation tests were conducted on copper converter slags to evaluate the relative merits of recovering copper from slow-cooled versus water-quenched slags. Three slags containing 1.6, 5.0, and 6.6 percent copper were used. More than 90 percent of the copper was recovered in a rougher concentrate leaving a 0.2- to 0.3-percent copper tailings when treating slow-cooled slag. Lower recoveries and higher copper tailings ranging from 0,5 to 0.6 percent copper were obtained from quenched slag. Grindability studies were made on the respective heat-treated slags. Quenched slags proved more difficult to grind than slow-cooled slags. Cost studies showed that (1) the cost of slow cooling and crushing off-sets any advantages of higher copper recoveries from slow-cooled slag, and (2) water-quenched slag, which requires no crushing preparatory to grinding, could be treated more economically. Costs based on processing 1,000 tons of slag per day would be $1.85 per ton for quenched slag versus $2.37 per ton for slow-cooled slag.

Jan 1, 1971

By D. J. Bauer

The Bureau of Mines demonstrated the feasibility of fractionating lanthanide nitrates with a tertiary amine on lanthanum-cerium and thulium-ytterbium pairs. Optimum values were determined for pH, phase concentration, and percent chelation of metal ions in the aqueous phase. Percent extraction is markedly dependent on the concentration of lithium nitrate in the aqueous phase. Selective masking of the heavier element in each extraction system with DTPA or EDTA aqueous-phase chelating agents resulted in lanthanum-cerium separation factors of 8.5 and thulium-ytterbium separation factors of 3.4.

Jan 1, 1966

By John J. Mulligan

Since 1941 the Federal Bureau of Mines has been conducting an intermit-tent program of placer and lode investigations to evaluate the potential tin resources of the western Seward Peninsula tin belt. Previous investigations were made in the Potato, Cape, Brooks (Lost River), and Ear Mountain areas. As part of this program the Bureau made a reconnaissance of reportedly tin-bearing stream gravels in areas adjacent to the previously worked tin deposits at Lost River and Potato Mountain. The objective of the reconnaissance was to determine if additional areas might be favorable for lode or placer exploration. The work was begun late in the fall of 1956 and completed during the following summer. The streams sampled were the Lost River and York Creek in the Brooks Mountain area and the Anikovik River and Kigezruk and Baituk Creeks in the York area. Samples were obtained by churn-drilling methods employing conventional placer-evaluation procedures. Holes were drilled at wide intervals at sites chosen as being representative of drainage areas rather than of individual gravel deposits. Minor to trace amounts of tin were found in the gravels of all these streams, but the highest grade was 0.35 pound of tin per cubic yard in the gravels of Lost River below the mouth of Tin Creek. Small amounts of gold were found on Baituk Creek and in one hole on the Anikovik River; the highest grade did not exceed 10 cents per cubic yard. Traces of scheelite and barite were found on York Creek, chromite was encountered in one hole on the Anikovik River, and minor amounts of titanium minerals (probably derived from basaltic intrusives) were found in the York area.

Jan 1, 1959

By Hillary W. St. Clair

The reduction zone of the iron blast furnace is represented by a mathematical model of the chemical reactions and heat transfer that occurs between gas and solids during the deoxidation of iron oxide. The model consists of a set of equations and an algorithm whereby the equations may be solved to give the temperature and composition of gas and solids at any position in the reaction zone and at any time after a specified initial state. The model is applied to the special case in which ferric oxide is reduced by graphitic carbon and carbon monoxide produced by burning carbon in dry air. The rate of reduction, carbon consumption and maximum temperature are shown as functions of the temperature and rate of flow of the incoming reducing gas and external heat loss. The model of the reduction zone is the essential part of a general mathematical model for simulation of the iron blast furnace. The simulation model will serve as a research tool to be used in conjunction with an experimental or operating furnace. After the simulation model has been correlated with the real furnace, it is proposed that further experimentation be done mostly with the model. The real furnace will then be operated primarily to test and confirm the model.

Jan 1, 1967

By H. O. McDonald

The Bureau of Mines reviewed the chemical vapor deposition (CVD) literature of the group IVB, VB, and VIR elements. This review was utilized in the Bureau's research to provide erosion-, abrasion-, and corrosion-resistant coatings for valve components used in coal gasification units. This report attempts to bring together the many CVD references that have been published since 1966. Each of the group IVB, VB, and VLB metal coatings were reviewed, and some of their preparation methods, uses, and properties are given. A total of 160 references were found for the nine elements. Isotope separation, stronger steels, solar absorbers, alloys, superconductors, optical fibers, and coatings to increase the life of materials are some of the new uses for CVD.

Jan 1, 1979

By Benjamin C. Pollard

The location and production potential of a large block of strippable reserves in North Dakota were determined by using published data as a base and adding new drill hole data or other data contributed by companies that presently own or lease coal lands. Only beds exceeding 5 feet in thickness, under less than 120 feet of overburden, and in large blocks of 5 million tons or more were included in the estimates. All such reserves are in the Fort Union Formation of western North Dakota and are lignite in rank. Sixteen large blocks of reserves evaluated in this study are estimated to contain a total of 4.1 billion tons of strippable lignite.

Jan 1, 1972

By R. G. Warncke, Stanley M. Walker

The United States Bureau of Mines was created by an act of Congress in 1910 as a governmental agency to work , on a national scale , toward reducing the huge annual loss of life in the production and processing of the Nation's minerals . From 1906 to 1910 , inclusive , nearly 2,500 miners lost their lives in 84 major explosion disasters , and more than 13,000 suffered fatal injuries from all causes in the coal mines of the United States . Also , conditions in the metal and nonmetal mines were proportionately hazardous during this period , and the total loss of life in all mines and quarries exceeded 3,000 annually and approximately 250,000 workers suffered serious injuries . Under these conditions it is readily understandable why Congress took notice of this " high cost of mining" , and from the investigations and hearings of the day emerged the Bureau of Mines charged with the prevention of accidents and the preservation of the health of all those engaged in the mineral industry; this has continued to be a most important part of the work of the Bureau . Throughout its existence the Bureau of Mines has had no legal authority of enforcement , except during war years , when enforcement necessary to the national security was given to it . The Bureau believes that persuasion , with factual evidence , is the proper and best way to obtain compliance with the safety suggestions made by its engineers and scientists . There is no panacea for accidents , nor will any single " approach " , instill safety consciousness in all workers , and without it accidents will occur --and occur again . To persuade men to work safely, numerous forms of appeal are required to reach the various temperaments of workers in many types of mines operating under diverse conditions .

Nov 1, 1949

By R. L. Rough

The Bureau of Mines analyzed rotary-coring-operations data to compare mud and air as coring mediums, and to compare core recoveries, penetration rates, and cost data for the respective mediums as part of an investigation of the susceptibility to secondary-recovery techniques of petroleum reservoirs in Ohio, Pennsylvania, and West Virginia. This report describes the rotary-diamond coring equipment and operations employed while coring 20 wells--10 cored using mud, and 10 cored using air. Data relevant to the draw works, rotary-table power, drill pipe, drill collars, core barrel, core head, mud pumps, or air compressors are tabulated. Average bit weight and rotary speed, core recovery, and penetration rates are listed for each formation cored. In general, core recoveries were better from the mud-cored wells, whereas penetration rates were faster for the air-cored wells. Coring costs were about the same for single-formation wells cored with either mud or air; however, costs increased considerably when multiple-formation wells were cored with air.

Jan 1, 1969

By M. L. Wouden

In the late 1970's, the Bureau of Mines began to examine the criteria for reestablishing vegetative cover on coal strip mine spoils near Glenrock, WY. A 9-acre plot, consisting of (1) spoils covered with topsoil, (2) spoils without topsoil, and (3) spoils treated with sewage sludge, was constructed. These plots were seeded with Tegmar intermediate wheatgrass (Agropyron intermedium), Fairway crested wheatgrass (A. cristatum), and Critana thickspike wheatgrass (A. dasystachyum). After 5 yr, the topsoil had about 70 pct plant coverage. Revegetated spoils, without topsoil addition, averaged approximately 30 pct plant coverage, and sewage sludge-treated spoils had about 45 pct plant coverage. Comparison of grass types showed the intermediate wheatgrass produced greater surface coverage.

Jan 1, 1986

By William J. Campbell

The purpose of this investigation was to develop a rapid, accurate method of analysis for small amounts of calcium in wolframite concentrates. This analysis is necessary to determine if the wolframite concentrates meet United States National Stockpile Specification P-57R2, which limits the calcium content to 0.2 percent. Because of the small depth of the sample analyzed in fluorescent X-ray spectrography, the calcium Kaline intensity was a function of the chemical composition of the calcium-bearing particle as well as the total matrix composition. This particle-composition effect was particularly important in this analysis, as the calcium may be present as a carbonate, tungstate, phosphate, etc. Three methods of preparing the sample eliminated the variation of calcium Ka intensity with mineralogical occurrence: (1) Reduction in particle size by extensive grinding, (2) chemical fusion with sodium carbonate, and (3) solution of the calcium by an acid attack.

Jan 1, 1958

By Larry A. Haas

A major problem encountered in dump leaching operations is the plugging of both the dump and the piping by precipitated iron compounds. Bureau of Mines research to obtain basic data on agitation leaching and dump leaching methods has shown that the addition of organic chelating reagents can significantly enhance the lixiviant permeability through the ore and the concentration of the metal values in the liquor. For example, the addition of 5 giL citric acid (CA) to a conventional sulfuric acid lixiviant almost doubled the fluid flow rate through 5-cm-diameter laboratory columns containing copper ore. After 185 h of per-colation leaching, the metal concentrations with (and without, in parentheses) CA were 1.7 (1.5) giL Cu, 200 (70) ppm Mn, 160 (40) ppm AI, and 6 (3) ppm Co. The enhancement of metal concentrations with chelating reagents such as CA was confirmed by determining the solubil-ity of several metal ions as functions of pH and chelating reagent con-centration. When ferric ions became insoluble at pH values above 3, the concentrations of other ions also decreased. The addition of che-lating reagents kept iron, as well as the other dissolved metals, in solution even at pH values as high as 5. Citric acid was a more effective chelating reagent than gluconic acid, oxalic acid, or sodium lignin sulfonate.

Jan 1, 1985

By W. A. Calhoun, M. M. Fine

"One of the most important wartime activities of the Bureau of Mines was the search for new sources of mineral necessary to the prosecution of the war. Part of that effort was in the form of metallurgical service extended to other government agencies engaged in purchasing and stock piling some of the more critical and strategic materials.Fluorite was one of the materials stock piled by the Metals Reserve Company. The fluorite was usually in the form of coarse metallurgical con¬centrate purchased in the United States and abroad. The material was stock¬piled to insure an adequate reserve of fluorite for the metallurgical industries. The domestic production of metallurgical fluorite containing a minimum effective calcium fluoride content of 55 percent,4/ however, gradually increased until production was at least equal to consumption. The stock-piled metallurgical fluorite, therefore, soon became a surplus commodity.On the other hand, the supply of acid-grade fluorite, containing a minimum of 97.5 percent calcium fluoride and n maximum of 1.5 percent silica,5/ was never entirely adequate. Increased consumption of acid-grade material in the aluminum, petroleum, and chemical industries kept that material on the critical list during the war.Under the circumstances, it was felt that a study of the possibility of producing acid-grade fluorite from the metallurgical stock piles would be of some benefit to the war effort. Consequently, samples of fluorite from several of the Metals Reserve Company stock piles were tested by the Bureau of Mines at the request of the War Production Board.Two groups of samples were submitted for testing. One consisted of metallurgical fluorite purchased from Mexico and stock-piled in the El Paso and Laredo, Texas, stock piles of the Metals Reserve Company. The second group of samples was from the stock piles at Gila, N. Mex.The sample submitted from the El Paso stock pile consisted of about 5,000 pounds of minus 4-inch material. Mineralogically, the sample consisted of fluorite contaminated by calcite, chert, quartz, and small amounts of iron and alumina. Although some of the fluorite was reasonably free from gangue at minus 1-inch, much of it remained locked in sizes as fine as 65-mesh.The Laredo sample was about 5,000 pounds of material from five different piles. The samples from each stock pile, A to E, inclusive, were analyzed separately to determine whether the grade of the material in the piles varied markedly. As there was little difference in the analyses, the samples were combined in proportion to the tonnage represented to make a composite sample for testing. The composite sample consisted of fluorite with small amounts of quartz, calcite, and barite. Most of the fluorite was the dark-colored, opaque variety. A small amount of iron-oxide staining was present, and traces of muscovite, clay, pyrite, and tourmaline were noted. The quartz was present as crystals in vugs, and as finely disseminated grains in the fluorite. The druzy quartz and the calcite were free at minus 10-mesh, but the disseminated grains, some of which were 1 to 15 microns in size, were not entirely free at minus 270-mesh. A petrographic estimate indicated that 65 percent of the silica was locked in the 150- to 200-mesh."

Jun 1, 1946

By James M. Nishi, Lloyd Carpenter

Sixteen elements were determined spectrochemically in the general range of 3 to 1,000 ppm in high - purity columbium . Samples were converted thermally to Cb2 O , mixed with graphite and Ge02 , and excited for 15 seconds using a 15 - ampere dc arc . For the molybdenum determination , the oxidized samples were mixed with NaCl and Geo₂ and excited for 30 seconds . Spectra were recorded on photographic plates , and spectral line transmittance values were measured photometrically . Relative - intensity ratios of selected analytical and internal standard spectral lines were plotted against concentrations of standards to form curves from which concentrations of impurities were read . Average precision of the method was 11.2 percent relative standard deviation .

Jan 1, 1964

By R. L. Lincoln

The effects of adding from 1 to 50 atomic percent (a/o) to vanadium were investigated by the Bureau of Mines. Properties studied included as-cast and annealed hardness, microstructure, fabricability at room temperature and elevated temperature, tensile strength, electrical resistivity, and oxidation resistance at 625° and 800° 2. Additions of small amounts of hafnium resulted in lessened as-cast hardness, decreased electrical resistivity, impaired roll- ability, increased oxidation resistance, and greater tensile strength. Larger amount of hafnium caused greater as-cast hardness, increased electrical resistivity, further impaired rollability, continued increase in oxidation resistance, and lessened tensile strength. INTRODUCTION The purpose of this study was to determine the effect of hafnium additions on the properties of vanadium and to learn if this binary alloy had any special or unusual properties. This investigation is a part of a larger research project in which new and expanded uses of vanadium are being sought. Domes tic vanadium is found frequently in combination with uranium, and because of the demand for uranium as a nuclear fuel, there now exists a surplus of vanadium-bearing minerals and vanadium pentoxide as a byproduct of uranium production. Primary principles of conservation demand that greater use be made of this readily available surplus; finding suitable metals to alloy with vanadium to enhance its properties is one way to increase its utilization. This report is the result of an investigation of the effects on the properties of vanadium when hafnium is added in amounts from 1 to 50 a/o.

Jan 1, 1962

By James J. Dowd

The investigation to evaluate the reserves of coking coal is being made by the Bureau of Mines in three parts: (1) To estimate known (measured plus indicated) recoverable reserves of all coking coal, (2) to upgrade marginal coals through effective preparation, and (3) to study the carbonizing properties of coal and coal blends not now widely used for metallurgical coke making. This is the seventh of a series of reports giving the results of studies by counties under part (1) of the investigation. (See appendix.) This report covers Floyd County, KY., which comprises parts of the Paintsville, Prestonsburg, Harold, Hindman, and Pikeville quadrangles. (See fig. 1.) A base map for each bed in each quadrangle was made to the scale of 1 inch equals 1,200 feet. Maps of mines, locations of drill holes, bed and total coal thicknesses, and the outcrop of the bed were plotted on the maps. With all avail-able data plotted, isopach lines were drawn to limit areas of known unmined reserves in beds up to 14 inches thick, 14 to 28 inches thick, 28 to 42 inches thick, and over 42 inches thick. These areas of coal reserves also were divided into "measured" and "indicated" categories. All areas in each thickness range and in each category, mined-out areas, areas excluded from the estimate but which may contain reserves based only on geologic inference, and areas outside of the outcrop were measured by planimeter on the base maps. Estimates of total reserves 14 inches and more thick and maps for individual beds were prepared from these data.

Jan 1, 1951

By W. A. Stickney, J. W. Town

Studies on continuous - circuit leach - aluminum precipitation and leachelectrodeposition of mercury were made by the Bureau of Mines to determine optimum conditions and cost estimates for recovering mercury from mercury sulfide flotation concentrates . With 150 grams of sodium sulfide and 50 grams of sodium hydroxide per liter , from 98 to 99.8 percent of the mercury was extracted from flotation concentrates , with about 0.5 pound of sodium hydroxide used per pound of mercury produced . Precipitation of mercury from the caustic - sulfide solution with minus 8 - mesh aluminum shot required about 0.2 pound of aluminum per pound of mercury produced at a cost of $ 0.05 per pound of mercury . Electrodeposition cost with 7 mill power , based on 50 percent current efficiency , was below 2 mills per pound of metal deposited . Feed solutions ranged from 10 to 130 grams of mercury per liter , and current densities , from 2 to 70 amperes per square foot . The cost of open- pit mining 250 tons per day was estimated at $ 1.75 per ton , and flotation - leachingelectrodeposition of the ore , at $ 3.54 , resulting in a cutoff grade of about 0.1 percent mercury . The cost of underground mining 50 tons per day was estimated at $ 20.00 per ton , and the cost of milling the ore was estimated at $ 13.33 , which resulted in a cutoff grade of 0.6 percent mercury .

Jan 1, 1964

By F. P. Haver

Because State and Federal agencies have limited the amount of sulfur oxides that can be discharged to the atmosphere, most copper smelters plan to convert the S02 in offgases to sulfuric acid. In some cases, however, it might be preferable to use a nonsmelting method to fix the sulfur in the form of a discardable product. Research by the Federal Bureau of Mines has shown that sulfur in copper concentrate can be converted into insoluble anhydrite (CaS04) by roasting the concentrate with lime (CaO). After leaching the calcine to recover metal values, the residue may be discarded without harm to the environment. The process can use a rougher flotation product, thus reducing separation costs and saving valuable minerals (for example, molybdenite) that are now lost in making cleaner concentrate. In tests, rougher concentrate was pelletized with the theoretical amount of lime and roasted for 1 hour in a 6-1/2-inch-ID by 11-foot-long rotary kiln at 700° C. Sulfur retention was about 97 percent. Leaching the calcine with 20 percent RCI extracted approximately 99 percent of the copper, 73 percent of the iron, and 91 percent of the molybdenum. After the molybdenum was removed from the leach solution by adsorption on activated carbon, copper with a purity in excess of 99 percent was obtained by cementation on sponge iron. The strip solution then could be spray-roasted at 500° C to recover the RCI for recycle and obtain F2O3 as a byproduct.

Jan 1, 1975