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By H. V. Fairbanks

It is estimated that millions of tons of coal fines are unsaleable each year due to difficulty of drying them economically with conventional mechanical dewatering and thermal drying equipment. The difficulty is due to the fact that coal of small particle size presents a large surface area with polar groups which have a great affinity for water. In order to remove this water thermally, a high temperature is necessary which oxidizes the surface of the coal. This substantially reduces the heating value of the coal. If drying could be satisfactorily carried out at a lower temperature, much more of the heating value of the coal fines could be retained. It was conjectured that acoustic energy applied during the drying process might prove to be of value since acoustic energy has the property of producing cavitation at a liquid-solid interface when the intensity is sufficiently great. This cavitation process produces water at room temperature which can be carried away from the solid surface by a flow of relatively cool air. Hence, moisture removal is made possible at a lower temperature.

Jan 1, 1966

By C. Villa Diniz

It is proposed that battery grade Mn02 can be produced directly from a manganese ore from Azul Mine in Brazil, by leaching with HCI to remove heavy metals selectively. We are working to find a way of selectively separating Cu, Ni, Co, Pb and Fe from the resulting acidic manganese chloride solution, to detoxify it and produce marketable chloride solution. Chelating ion exchange resins are proving more promising for this separation than solvent extraction with commercially available reagents. Results from batch and column ion exchange tests that characterize the behavior of copper, nickel, cobalt, lead and iron are reported.

Jan 1, 1999

By Patrick R. Taylor

Keywords: Thermal Plasma, Electroreduction, Electrolysis, Transition metals, Waste treatment, Molten oxides, Chromium oxide. An innovative process to treat transition metal oxide waste materials from diverse sources is presented. This technology involves using reverse-polarity DC plasma driven electrolysis in molten oxides. The process results in the recovery of the transition metal and other heavy metals from waste. By-products generated throughout the processing was converted to environmentally acceptable slag. The significance of this technology is that the treatment of the waste is accomplished in one step which in turn lowers the cost of remediation. Moreover, this process uses high temperature properties of thermal plasmas, which makes it possible to use molten oxides instead of halides as electrolytes. Chromium was successfully reduced from chromium oxide through the plasma driven electro-reduction process. It was shown that the selection of the appropriate ionic conducting oxides was critical for the formation of a slag that would enhance the reduction of chromium oxide.

Jan 1, 2004

By F Soleimani

Coal and gas outburst is a common hazard in coalmines and due to the complexity of its nature, efficaciously predicting the possibility of its occurrence is intricate. The mechanical and gas flow properties of coal, in situ and mining-induced stresses and geological structure are involved in outburst occurrence, whereas suggested thresholds for its prediction do not consider them all. Numerical modelling is known as an effective method that can not only consider couple the effect of different physics but also analyse the effect of associated parameters. In this paper, a coupled fluid flow and geomechanics model has been developed in COMSOL Multiphysics to simulate outbursts by considering the effect of gas pressure and composition, damage mechanics on related coal properties, and progressive excavation and mining-induced stress. For the proposed fully coupled outburst model, the effect of pore pressure and sorption are applied to the stress while the influence of stress changes and damage are considered in updating coal porosity and permeability in each time step. In addition, to study the effect of mining-induced stress, the excavation process is simulated by changing the material properties over time according to the schedule of heading development. Then, outburst initiation is analysed from the energy point of view by using the concept of energy conservation law. The simulation results are used in calculating energy sources of the outburst initiation, also, the effect of particle size and ejection velocity are studied, and the significance of particle size effect on the energy analysis and deformed coal on outburst initiation is discussed.

Oct 12, 2022

By Guowen Dong, Qiyong Li, Qiang Li, Tiejun Chen, Zhihong Wu, Junying Wan

In order to search for a more economical and effective roasting additive for extracting vanadium from stone coal and solve the question of the disposal of PVC waste, PVC waste was proposed as a novel roasting additive to enhance extraction of vanadium from stone coal and realize the comprehensive utilization of resources. By adding this roasting additive, the leaching rate of vanadium reached 94.5% under the conditions that the PVC waste addition was 10 wt%, the roasting temperature was 800 °C, the roasting time was 1 h, the sulfuric acid concentration was 15 vol%, the liquid-to-solid ratio was 1.5 cm3 /g, the leaching temperature was 95 °C, and leaching time was 4 h, which increased by 8.4% compared with that of blank roasting. The thermodynamics calculation showed that the decomposition reaction of mica was performed easier with the participation of HCl produced by pyrolysis of PVC. Meanwhile, The SEM-EDS and aperture test analyses demonstrated that more cracks and voids appeared in the roasted sample by roasting with PVC waste, which could facilitate the release and extraction of vanadium. Additionally, the TG-DSC analyses indicated that PVC could provide large amounts of heat for the roasting process to promote the decarbonization and roasting efficiency of stone coal because of its high calorific value.

By Tianzu Yang, Weifeng Liu, Lin Chen, Wei Chen, DUCHAO ZHANG, HUI XIAO

Carbonaceous refractory materials are widely accepted in many reducing smelting processes such as iron and ferroalloys. Oxidizing processes such as copper concentrate smelting traditionally use magnesia and/or alumina/silica refractory materials. The main objection to the use of carbon-based refractories as the exposed working lining in oxidizing applications is the potential for free oxygen to react with the carbon at high temperature, which could rapidly degrade the refractory lining. In 2013, Outotec and GrafTech conducted joint trials of a thermally conductive, carbonaceous lining for smelting copper concentrates in the Outotec® pilot-scale top-submerged-lance (TSL) furnace in Dandenong, Australia. This testwork had two equally important goals; to demonstrate the ability of carbon refractories to withstand oxidizing process conditions, while ensuring that neither furnace operating conditions nor process stability were negatively affected by the refractory material. The paper discusses the input parameters of the trials, key observations during the testwork program, and the results and conclusions from both process and refractory design standpoints.

Jan 1, 2016

By Winmill T. F.

(Paper presented at the Institution of Mining Engineers' general meeting held in London on 8th June 1916.) The conclusions reached in this paper may be summarized briefly as follows: (1) The method of estimating moisture in coal by determining the loss in weight of a sample heated to 105°-110° Cent, in an air-bath for an hour is untrustworthy, the results so obtained being too low. (2) Dried coal has a very considerable power of absorbing moisture, and a sample, after being dried, must be protected instantly if it is to remain free from moisture. (3) A fairly accurate estimation may be made by heating the coal in a current of dry air at 105° to 110° Cent., and collecting the moisture evolved. (4) In cases in which it is proposed to use the dried coal for any further experiments, the drying must be done in the absence of oxygen, and this can be done simply and quickly by the vacuum method now described

Dec 1, 1916

By S Bandopadhyay

The seasonal fluctuations of the dust content in Arctic mine environments and the environmental variables affecting the intensity of dust production are qualitatively well known, but quantitative models that allow simulation and prediction of dust generation and the effects of engineering control of thermal regime on the mine environment are still non-existent. In Arctic mines, the migration of moisture in the surrounding rock mass releases fine dust by freeing it from the ice matrix allowing it to escape into mine airway. The migration of moisture is the direct cause for the production of mine dust and heat is the primary driving force. This paper examins the heat and moisture exchange between the ventilation air and the surrounding rock mass in frozen ground, placer mines in the Arctic. Based on the simulated results of a coupled heat and mass transfer problem with phase change, methods of dust control have been identified for mines in the Arctic.

Jan 1, 2005

By William H. Lesser

Never before have mine managers in the anthracite region of Pennsylvania been so seriously concerned about the rising cost of pumping mine water. Many of them know that future pumping charges may affect their operating profits adversely to an extent that will make it necessary to abandon some mines. Increased pumping charges in the anthracite industry are currently comparable in importance with higher mining costs; in fact, profitable operation of some mines depends not only upon the cost of mining coal but also upon whether they can be kept free from water at reasonable cost. Pumping charges are relatively low during the early development of a mine, but they increase rapidly as development progresses. Numerous crop falls, strippings, and. abandoned adjacent properties contribute unfavorably to the volume of water produced during mining. The foregoing conditions and the existence of large underground pools below existing mining levels present water problems of such magnitude and cost that some mine owners cannot continue to operate profitably.

Jan 1, 1950

By Andreas Siegmund

During the decade of the nineties the conventional method of primary lead smelting (sinter machine/blast furnace) was successfully challenged by the introduction of novel direct and continuous smelting processes. In combination with a significant shift in market structure, as well as more stringent government regulations these modem technological innovations like the QSL, Kivcet, and Isa/Ausmelt processes became more than major competitors. They have proven to be economically and environmentally viable. The intensification of the metallurgical reaction by applying oxygen enriched or pure oxygen bath or flash smelting principles resulted in cost savings and a higher flexibility with respect to raw materials and additives usage. By synchronizing individual auxiliary plant sections with the smelting process a virtually waste-free production and low-emission mode of operation with nearly optimum energy exploitation is achieved. The primary lead industry will gradually substitute the sinter -blast furnace operation with novel high-energy efficient technologies in the new millennium.

Jan 1, 2003

By Ken-ichiro Uemura

"The DIOS process has been developed for eight years since 1988. The research project was started with the element studies carried out by each of the five integrated steel making companies in Japan, the final two and half years were spent for the pilot plant studies. Operation were conducted in the entirely closed and pressurized system successfully as planned. From the result, the DIOS process was proved to be viable as a future iron-making process substitutable for the conventional blast furnace. In addition, a lot of findings were obtained. Hot metal productivity was primarily determined by a oxygen flow rate, and a coal consumption varied depending on the productivity. The post combustion ratio was a little lower than expected from the result of the element study. It was supposed to relate the gas-reforming with coal or volatile matter in the free space of the furnace. Hot metal carbon content seemed to depend on the char content in slag.INTRODUCTIONThe JISF's DIOS pilot plant (DIOS=Direct Iron Ore Smelting Reduction Process) has finished its last campaign of the operations in January 1996. The project was started in 1988 as a joint research of the Center for Coal Utilization, Japan and the Japan Iron and Steel Federation (JISF) with a subsidy for promoting coal productions and utilization technologies from the Agency of National Resources and Energy, the Ministry of International Trade and Industry(MITI). Throughout the pilot plant test, a total of over 20,000 tons of hot metal was produced for more than 2,000 hours of the operation. Recorded production rate was 538 ton/day for 3 days at a specific coal consumption of approx. 1,000kg/hmt. Long-term operation was carried out in the fifth campaign for 18 days, which has proved that the entirely closed and pressurized DIOS process works well as planned. In Figure 1 is shown the representative operational performance obtained in the first five campaigns. The project is going to be finished by the end of March this year after investigating the technical viability and economic potential of the process, and completing the conceptual design of the DIOS commercial plant. In this paper, the system and facilities of the DIOS process are first introduced and some of the results of the pilot plant test are detailed later."

Jan 1, 1996

By N. S. Dalal, Xiaoya Sun, Xianglin Shi

"The in vivo toxicity of vanadium(V) has been found to correlate with the depletion of cellular glutathione and related non-protein thiols. With a view to understanding the mechanism for this observation, we have investigated the oxidation of glutathione, cysteine N·acetylcystcinc and pcnicil· lamine by vanadium(V), using electron spin resonance (ESR) and ESR spin trapping methodology. The spin trap used was 5,5-dimethyl-l-pyrroline I-oxide (DMPO). It is found that the oxidation of these thiols by vanadium(V) generates the corresponding thiyl radicals and vanadilim- (IV) complexes. The results suggest that free radical reactions play a significant role in the depletion of cellular thiols by vanadium(V) and hence in vanadium(V) toxicity. 1. INTRODUCTIONThis communication reports on the identification of thiyl radicals formed as intermediates in the reaction of vanadium(V) with glutathione (GSH) and related nonprotein thiols. This study was undertaken because the biochemical mechanism of vanadium toxicity is still not fully understood,. despite being a topic of current research activity [1-20). As to possible clues, it is known that vanadium is most toxic when administered in its pentavaient state [21), and that vanadium(V) administration into laboratory mice reduces cellular levels of NAD(P)H and GSH [22). While the oxidation of NAD(P)H by vanadium has been studied extensively [16-20), that of glutathione and related non-protein thiols has been paid less attention. On the other hand, GSH and related thiols are important cellular antioxidants [23). Their functions include decomposing lipid peroxides and protecting cell membranes [23-25). Thus any reduction in the cellular contents of such nonprotein thiols after vanadium exposure may result in the accumulation of lipid peroxides which might ultimately lead to tissue injury. With a view of finding the mechanism for this thiol depletion process, we have investigated reactions of non-protein thiols with vanadium(V). Particular attention has been paid to the detection of thiyl radicals, since it has been postulated [l] (but not experimentally proven) that the glutathionyl radical (GS·) might be an intermediate in the reaction between vanadium(V), NADH and GSH. We have used electron spin resonance (ESR) and ESR spin trapping methodology for investigating the reactions of GSH, cysteine, N-acetylcysteine and penicillamine with vanadium(V). The results show that the corresponding thiyl radicals are indeed formed in the one-electron reduction of vanadium(V) by all of the above mentioned thiols."

Jan 1, 1990

By R. W. Hiteshue, R. W. Fridy, W. Kawa

A study of the production of coronene , a high - melting ( 440 ° C ) , highboiling ( 525 ° C) , polynuclear hydrocarbon , was made by the Bureau of Mines to determine the maximum yield obtainable by the hydrogenation of coal and coalderived materials . Experiments were made with anthracite and bituminous coals and with asphaltenes and centrifuged residue obtained from heavy oil produced in a pilot plant by the hydrogenation of a bituminous coal at 2,000 psi and 480 ° C. With anthracite , yields of coronene of 0.5 to 0.7 wt pct of moistureand ash - free coal were obtained at 6,000 to 8,000 psi , 700 ° to 750 ° C , and a residence time of 30 minutes . With bituminous coal , yields averaging 0.4 wt pct of maf coal were obtained at 6,000 psi , 800 ° C , and 30 minutes ' residence time . With asphaltene and centrifuged residue , yields of less than 0.02 wt pct of maf coal were obtained at 6,000 psi , 700 ° C , and 60 minutes ' residence time .

Jan 1, 1964

By Burton J. Thamer

Radon emanation coefficients of 0.02 to 0.55 were measured at moisture contents ranging from dry to saturation in eighteen different ores. The emanation coefficients rose from a minimum when dry to a plateau usually starting at 5-20 percent of saturation. A model, using measured pore-size distributions, suggested that the radium mineralization may be confined to annular layers about 0.02 micrometers thick around pores. Radon's diffusion coefficient was determined as a function of moisture. The techniques involved comparing a disc's exhalation as a function of time whether or not the disc had a distributed source. The model was free of approximations and included the effects of porosity and adsorption. An increase of diffusion coefficient with moisture for one or two ores was explained in terms of a model's equation for the diffusion coefficient in terms of both volume and surface diffusion. Radon's adsorption coefficient was determined on a uranium ore.

Jan 1, 1981

By Andreas Siegmund

During the decade of the nineties the conventional method of primary lead smelting (sinter machine/blast furnace) was successfully challenged by the introduction of novel direct and continuous smelting processes. In combination with a significant shift in market structure, as well as more stringent government regulations these modem technological innovations like the QSL, Kivcet, and Isa/Ausmelt processes became more than major competitors. They have proven to be economically and environmentally viable. The intensification of the metallurgical reaction by applying oxygen enriched or pure oxygen bath or flash smelting principles resulted in cost savings and a higher flexibility with respect to raw materials and additives usage. By synchronizing individual auxiliary plant sections with the smelting process a virtually waste- free production and low-emission mode of operation with nearly optimum energy exploitation is achieved. The primary lead industry will gradually substitute the sinter -blast furnace operation with novel high-energy efficient technologies in the new millennium.

Jan 1, 2003

By D. A. Meyn, R. L. Holtz, C. S. Pande, M. A. Imam, D. J. Singh

"Various theoretical and experimental techniques used to search and develop new metal hydride systems suitable for hydrogen storage are described. The main theoretical technique under study makes the use of electronic structure of the candidate materials. Microstructural characterization techniques like transmission electron microscopy are being used to study the hydride formation. Novel processing techniques for material preparation such as those needed to produce thin films or amorphous phases are also being utilized. The techniques are illustrated with results from Pd, FeTi and Mg2Ni systems.IntroductionOf the four methods of hydrogen storage, compressed gas, cryogenic liquid, metal hydrides, and gas-solid adsorption, the metal hydride storage method is more attractive from the point of view of high volumetric density and safety. Compressed gas storage has disadvantages of extreme pressure, weight, and volume requirements, whereas storage of hydrogen as cryogenic liquid is unattractive due to the requirements of extremely low temperatures and high consumption of primary energy. Moreover, the number hydrogen atoms present in a volume of 10- 22 Cm3 (nH) in liquid hydrogen state (- 20K) is 4.2 whereas number of hydrogen atoms that can be accommodated in a free volume of 10-22 cm3 of various hydrides are as follows: LiH--5.9, TiH2--9.2, ZrH2--9.2, VH2--l0.2. High hydrogen concentration is usually associated with a large H/Metal atomic ratio but is also a function of structure."

Jan 1, 1994

By K Mayank, A N. Mainza, I Govender, M Narasimha, A Mittal

In mineral processing industries grinding is the most energy-consuming process. A tumbling mill is an essential grinding equipment widely used for particle size reduction. Power consumption, impact forces and trajectory paths are critical parameters for characterising a tumbling mill to determine grinding efficiency. The effect of lifters and mill speed plays a vital role in such parameters. However, most of the studies ignore the impact of the lifter and do not investigate the effect of slurry dynamics on charge motion. The focus of the present work is to prepare a computational model that can accurately predict the complex multi-phase dynamics of charge particles, air and slurry inside the mill using a model that couples computational fluid dynamics (CFD) and the discrete element method (DEM). The details of impact forces with lifter profiles and mill speed variations will be refined even further using the CFD-DEM coupling approach. The slurry-air free surface is modelled using the volume of fluid (VOF) method, and the charge motion is modelled using the DEM. The phases are coupled using the interface momentum exchange between the charge and the fluid slurry. The coupled model is validated against experimental results from the positron-emitting particle tracking (PEPT) data. The validated model compares the effect of slurry content on charge dynamics with the dry DEM model. The presence of slurry is observed to dampen the tangential and shear contact forces.

Aug 24, 2022

By A. J. Kraemer, H. M. Thorne

The following account of oil-shale operations in Australia is based upon infor- mation obtained by the authors while visiting Australia from September 15 to October 7, 1947, supplemented by published data, and augmented by analyses of samples of oil shale and its products at the Oil-shale Research and Development Laboratories of the Bureau of Mines at Laramie, Wyo. The primary objective of the authors' trip to Australia was to obtain, first hand, information regarding the equipment and methods used by National Oil Proprie- tary, Ltd., at Glen Davis, New South Wales, in mining oil shale, extracting oil from it, and refining the shale oil. This company was operating the only oil-shale plant that had been active in Australia since 1945. The plant comprised an oil-shale mine, 104 modified Pumpherston (Fell) retorts in 2 batteries, a hele refinery, and a 3-inch gusoline pipeline to the railroad loniing terminal t Sun Junction, 30 miles away. There were, also, the usual and necessary any uralities, such as a power house, mechanical shops, offices, and laboratories One Information regarding the company's operations was wance because of its bear- Ing upon the synthetic liquid fuels program of the Bureau of Mines, pursuant to the Synthetic Liquid Fuels Act of April 5, 1944 (30 U.S.C., 321-325, as amended). objective of the Bureau's program. In accordance with the maniate of the Act, is to furnish American industry cost and engineering data necessary for the development of synthetic-liquid fuel industry, and an obvious means of obtaining some of these data is to learn how oil shale is being mined and retorted and how shale oil is re- rined in countries where these operations have been conducted on a plant scale for many years. The authors spent 2 weeks at the plant of National Oil Proprietary, Lt., at Glen Davis, and were afforded every opportunity to obtain letailed and specific information regarding all aspects of the company'a operations.

Jul 1, 1951

By Roy L. Soderberg

The Bureau of Mines has conducted substantial research on the design, construction, and operation of metal and nonmetal tailings ponds. This design guide, like related Bureau publications that preceded it, is produced to assist the industry in the management of mill tailings disposal. It covers the site selection, sampling, laboratory testing, design, construction, operation, and inspection of tailings embankments. The effects of environment, topography, and hydrogeology are also included, and various methods of stability analysis and factors affecting stability are reviewed. Because of the diversity of problems encountered in tailings embankments, specific solutions are not intended. The guide is, however, a useful checklist for designers, operators, and inspectors of this type of structure.

Jan 1, 1977

By Thiago Rangel Bittencourt

Com a tendência de aumento da complexidade geométrica dos painéis de cobertura dos automóveis, aumento de resistência mecânica e diminuição da espessura dos materiais, a estampagem dessas peças tem tornado cada vez mais difícil. Neste contexto, dois graus de aços que exibem elevada resistência mecânica e boa conformabilidade, têm sido ofertados pela siderurgia à indústria automotiva, o Bake Hardenable (BH) e o Interstitial Free High Strength Steel (IFHSS). O presente estudo teve como objetivo avaliar aços BH e IFHSS, em termos de propriedades mecânicas, de conformabilidade, de ganho de resistência em função da deformação, envelhecimento e de resistência à indentação, em escala laboratorial. Desse modo, visou-se avaliar sob quais condições de estampagem deve ser decidido o uso do BH ou do IFHSS em aplicações de painéis automotivos. Os aços avaliados, de um modo geral, apresentaram desempenho similar em termos de conformabilidade. O aço BH foi superior ao IFHSS em relação à resistência à indentação. Portanto, o aço BH aparece como uma solução técnica atrativa, comparativamente ao aço IFHSS, quando aplicado em painéis externos (capôs, portas e paralamas) que requerem maior exigência quanto à resistência à indentação.

Aug 7, 2018