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By Albert J. Forney

A process for the manufacture of high-Btu gas from coal has been developed by the Bureau of Mines. The process consists of fluid-bed gasification of the coal, followed by the gas treatment steps of gas purification and methanation. Advantages of the system are that caking coals can be used directly, and more than half of the ultimate methane is made in the gasifier.

Jan 1, 1970

By Madaah Hosseini H. R., P. Abachi, S. Miraghaei

In this study, the effects of milling time, chemical composition and heat treatment on microstructure and magnetic properties of nanocrystalline Fe-Si (6.5-25 at.% Si) alloys prepared by mechanical alloying have been investigated. The results show that increasing the milling time or the Si content, decreases the lattice parameter and increases the internal microstrain. The prepared powders mainly consist of micron-sized particles with an average grain size of less than 20 nm. The specific saturation magnetization values are slightly less than those of single crystal or conventional Fe-Si alloys and decrease as Si content increases. The coercive force values of the nanocrystalline as-milled powders are much higher than those of corresponding Fe-Si bulk alloys with a minimum at 13.5 at.% Si. The values of coercive force decreased after annealing but it seams that the residual strain developed during milling is not the major contributing factor to the higher values of coercive force in the mechanically alloyed powders and nanocrystals behave as single-domain particles without exchange interaction between them.

Jan 1, 2006

By R. B. Shu

A moderate thermophilic microorganisms, has been isolated (45?) from a typical sulphide mine in the region of Mo Jiang located in the southwest of China. The culture has been used to extract copper from chalcopyrite concentrates obtained from De Xing copper mine. The majority of experiments were carried out in 300mL Erlenmeyer flasks containing 150mL volumes of mineral suspension. Effects of some variable parameters such as solids concentration, pH and the concentrations of inorganic nutrients on the bioleaching of chalcopyrite obtained from De Xing copper mine were investigated. For a given concentrate the most important factor affecting the fractional copper extraction was the size of the mineral particles. The overall rate of leaching was found to be limited by the area of mineral surface. The attack started in cracks and genetic defects and finally reached the whole chalcopyrite surface. As a consequence of this, the ore showed strongly cracks. The additive of ferrous sulfate increases the bacteria activity, but did not improve chalcopyrite bioleaching. The results indicate that the nature and relative proportions of the various minerals present have been shown to be important factors.

Jan 1, 2014

By R. X. Li

The overall flow-sheet of producing chromium (III) sulfate is described in this paper. The suitable conditions of each process such as sintering, leaching, aluminum removal, reduction, and de-composition conditions were experimentally studied. The results show it is reasonable to produce chromium (III) sulfate with the flow-sheet pointed out in this research work. The final product is Cr2(SO4)3 solution contained 150~250g/L Cr.

Jan 1, 2014

By R. A. Wyman

A comparison of the amount of minus-28-mesh product produced by a standard grinding test procedure is provided for 45 non-metallic materials. The percentage of product, the weight of product per unit of energy used and the weight of product per mill revolution are shown. The results exhibited excellent reproducibility and demonstrated an accurate comparison of grindability for non-metallic materials.

Jan 1, 1977

By Olga D. Khmelnitskaya

The paper presents the results of research on the development of gold recovery technology from oxidized gold-copper ore of one of deposits in Russian Federation. Gold and copper grades in the ore are 9.5 g/t and 0.4%, respectively. Various options of flowsheets, such as direct cyanidation, thiourea leaching, flotation and gravity concentration followed by subsequent cyanidation of con-centration products, were tested. It was established that gravity-cyanidation technology with filtra-tion leaching tails and the use of solutions in the recirculation is the optimal option for ore treatment. The proposed flowsheet provides gold recovery for 91.0% at NaCN consumption 2.5 kg/t ac-cording to the results of pilot testing. Ammonia-cyanide gold leaching was also examined. In comparison with cyanidation, gold leaching solution in system NaCN-NH4OH-(NH4)2CO3 allows NaCN consumption to be reduced three times from 4.5 kg to 1.5 kg per 1 ton of the ore and provides the same gold recovery. Based on the laboratory and pilot plant tests results of gravity-cyanidation technology of gold dissolution, process design criteria were developed.

Jan 1, 2014

By George Langford

Introduction The manufacture of ductile beryllium is one of the most interesting problems confronting the metallurgist today, and one which becomes more acutely in need of resolution as the uses for beryllium increase. Beryllium belongs to the hexagonal group of metals along with zinc, magnesium, and cadmium. The melting point of the metal is about l,280°C. ± 5°C. Due to its brittleness, the metal's chief use is as an alloying agent in copper and iron. The very low absorption coefficient of beryllium for x-rays makes the metal ideal for x-ray windows, and, similarly, because of its low capture cross-section for neutrons, the metal holds a preferred position in the field of nuclear physics. Modern x-ray diffraction methods were responsible for explaining the mechanism whereby zinc metal, although brittle when cast, could be made ductile at room temperature. The diffraction patterns of zinc and magnesium indicated the importance of the parts played by recrystallization and preferred orientation in this mechanism. It was with this in mind that an Investigation into the recrystallization and preferred orientation of beryllium was undertaken. The investigation, after a series of experiments were conducted involving cold-working and annealing, yielded the recrystallization temperature curve for beryllium. Both the texture of preferred orientation and the effect of recrystallization on this texture when subjected to compressive stresses were also determined. W. A. Alexander, J. K. Swinton and L. M. Pidgeon, in their investigation on The Recrystallization Temperature of Beryllium (C.I.M., Trans., Vol. L, 1947, pp. 657-664), utilized the Brinell ball as a means of cold straining the metal. Sufficient strain was developed to estimate the recrystallization curve for the metal. However, in order to determine the lowest recrystallization curve, as well as to develop a preferred orientation structure, larger deformation than that possible with a Brinell ball was required. The plastic deformation of beryllium can be carried out at an elevated temperature above 700°C. Above 850°C., the metal is quite ductile and can be readily compressed or extruded.

Jan 1, 1948

By G. A. Howes

This is one of a series of circulars dealing with the cost of equipping and developing mining properties in the United States and Canada, prepared and published by the Bureau of Mines in cooperation with various mining and exploration companies. This group of circulars is designed to supplement an earlier series which covered the methods and costs of mining and milling at a large number of producing properties. ACKNOWLEDGMENTS The authors desire to thank Robert A. Bryce, president of Macassa Mines (Ltd.), for permission to use the data presented in this paper, and to acknowledge the cooperation of A. J. Keast, under whose direction as manager the plant was installed and equipped and the shaft was sunk to a depth of approximately 2,000 feet.

Jan 1, 1932

By Richard L. Sayrs

The Eve Mills deposit is in Monroe County, Tenn., near the southeastern corner of the State. The deposit was examined in February 1943 by a Bureau of Mines engineer, and drilling the property was recommended to increase the on: reserves enough to justify mining should war needs require it. The deposits were explored, by 32 diamond-drill holes totaling 11,649 feet during the periods from July 1943 to November 7, 1945, and from April 1944 to August 17, 1944. The drilling campaign disclosed a large area of mineralization. The ore, however, is apparently confined to long, narrow sheets. The indicated grade of the ore bodies blocked cut by the Bureau of Mines is 4.o8 percent zinc and 2.10 percent iron.

Jan 1, 1949

By Drew Sinha

Success of the environmentally benign semiconductor manufacturing depends on the cost-effective integration of the principles of reduce, recover, reuse and recycle from source material to final product disposal. Increasing demand combined with current shortage of polysilicon provided unique opportunities to recover the silicon waste, caused by various defects, in wafer manufacturing process. Current practices relating to recovery and reuse of waste silicon produced, from crystal growth process to finally polished and epitaxially deposited silicon wafer, at Mitsubishi Silicon America is presented. Future plan to recycle the process generated silicon fines produced during the intermediate steps of the wafer manufacturing process such as grinding, slicing, lapping and polishing is also discussed.

Jan 1, 1998

By A. V. Bogdanovich

Until recently, in consideration of fundamentals of gravity concentration theory, all computations have been based on determination of particles? fall velocity in an unrestricted medium (hydraulic size). Meanwhile, gravity separation processes are realized under conditions of particles? restricted fall, when important and sometimes decisive role is played by interacting forces of particles, dependent on their varying size, density and shape, i.e., segregation forces. We have developed devices and methods for measuring segregation velocities of fine particles of various size, density and shape during their loosening in air or aqueous medium. Besides, to exclude influence of medium upward flows, loosening was provided by superposition of vertical harmonic oscillations on measuring cell. It was established, that maximum segregation velocities are observed at certain optimal acceleration values and amplitudes of oscillations; excessive loosening leads to mixing and worsening of segregation. Velocity of some particles segregation through others depends on particles? size, density and shape, as well as nature of medium (air, water). Absolute segregation velocities of particles in air medium may reach 1~2 mm/s, in aqueous medium such velocities are by an order smaller. Analysis of rare-metal sands material gravity concentration results showed, that owing to segregation process during gravity separation, fine-size isometric particles of heavy minerals are recovered into gravity concentrates more actively, than larger ones, but more elongated in shape. It is convenient and simple to estimate mineral grains? shape by extent of their oblongness, described as ratio of particle minimal dimension to maximum. Besides, mineral mixtures gravity separation results are directly related to extent of oblongness of heavy particles, recovered in gravity separation process, and also to root-mean-square coefficient of their shape variation. The performed research showed that particles segregation in gravity concentration process plays not a lesser role, than hydrodynamics parameters, and demands further theoretical inquiry and experimental studies.

Jan 1, 2014

By J. L. Uhrie

A potentially cost effective technique for the reclamation of heavy metal contaminated soils and sediments involves the technique of froth flotation. Heavy metals sorbed to clays in the soil may be sulfidized by the introduction of sodium sulfide and floated using a dithiophosphate collector. Separations were obtained where up to 78% of all copper ion was removed from the system. Selected samples were floated in a column cell but little advantage was seen.

Jan 1, 1996

By S. Gaydardzhiev

Laboratory batch tests having preliminary and orientation character aiming at improvement of the molybdenum flotation at Ellatzite copper processing plant in Bulgaria have been conducted. The following technological parameters have been screened to study their influence on the grade and recovery of copper and molybdenum during the rougher flotation stage: flotation pulp density, pH, addition of secondary collector and replacement of MIBC by pine oil as a frother. The results have shown that slightly better grade/recovery figures could be obtained for both copper and molybdenum at lower flotation pulp densities. The addition of kerosene has improved the recovery of molybdenum however, on the expense of that of copper. The effects from pH variation and the replacement of MIBC by pine oil as a frother have been almost negligible.

Sep 1, 2012

By C. Eddine

"Can we use data to make communication effective? How does one successfully tackle the challenge of solving cultural differences and harmonizing the needs of diverse stakeholders while developing and maintaining a strong and reliable corporate image? Is it possible to achieve better engagement and minimizing risks with data? This paper aims to explore human rights and business procedures, the promotion of shared prosperity in a sustainable manner and the use of metrics to guide decision-making process. Among the topics examined are: • the significance of stakeholder engagement in community development projects; • the use of grievance mechanisms to give a voice to First Nations and communities / populations in vulnerable positions (including children and elders); • the benefits of configuring and implementing a feedback system in partnership with the communities. This research is a preliminary initiative and has limitations on the extent of the material used. The author acknowledges there is a vast amount of work and publications available on this subject, as well, as a variety of examples that have not been included. The intention is to keep developing this research to assess and expand how data can be used to minimize risks and improve engagement, in addition to inspire others to continue advancing this topic. Natural resources consumption is a reality that will not disappear in a foreseeable future. Several developments and operations are located in remote areas where communities in vulnerable situation and Indigenous Peoples live. Feedback systems are being ratified as a tool to help tackling the challenges of harmonizing cultural differences and fulfilling the needs of diverse stakeholders. Integrating social, environmental, and economic values plays an imperative purpose in preserving a productive and trustworthy relationship with stakeholders. Positioning social standards next to environmental and economic principles shows inclusiveness and firm intention of integration. We add value to a positive image of our industry by embracing responsibility for corporate actions and promoting their beneficial impact on the environment. The social context within communities, groups and organizations is dynamic and presents new challenges as connections evolve. There are wildly diverse expectations which one may need to address during exploration, construction and operating phases. Disagreements are an inevitable consequence of interactions due to the different needs and requirements of the parts involved. Nevertheless, balancing differences and solving conflicts can offer remarkable opportunities for improvement."

Jan 1, 2016

By J. Iannicelli

Kaolin, normally an inert filler when compounded with polymers, is converted into a strongly reinforcing pigment by prereaction with certain functional silanes. Modification of kaolin with amino and mercapto silanes allows it to form crosslinks and confers significant improvements in modulus, abrasion resistance, compression set and other physical properties of a broad range of polymers.

Jan 1, 1990

By A F. Kravic

Carbonyl nickel powders of irregular particle shape and low a11parent density are used extensively in the production of porous nickel electrodes for nickel-cadmium storage batteries and hydrogen-oxygen fuel cells employing alkaline electrolytes. Such porous nickel matrices are at-tractive for these intended applications as they are relatively inexpensive, are corrosion resistant, have good electrical conductivity, can be welded to form electrical contacts, have a long life (as demonstrated in alkaline storage batteries), and are rugged and vibration and shock resistant. This paper describes a feasibility study concerning the production of porous multi-layer nickel electrodes by the pressing and sintering of stacked layers of green-powder rolled nickel sheet. Background H AUSNER (1) conveniently listed nine different powder compaction processes used for forming metal powders into useful shapes. These are shown in Table I. There are additional powder metallurgy processes; however, most of these are combinations of two or more processes listed in the Table. A study of the literature revealed that every powder compacting process, with the exception of isostatic pressing and explosive forming, has been evaluated or is being used for the manufacture of porous metal electrodes.

Jan 1, 1965

With the ambitious target of adding another 2,00,000 MW of power generation by the year 2017 in India the demand for coal is bound to grow. The non-coking coal deposits in India are characterized as high ash and difficult-to-wash coals. Quality improvement by beneficiation is almost mandatory due to MoEF notification to use <34% ash coal for all power plants except those located at pithead. Most of the coal washeries in India are based on wet process, where the coal fines are allowed to settle in thickeners. The coarser particles settle faster leaving the fine particles suspended for longer period. The dispersed fine coal particles contain some surface charge, which leads to the development of electrical repulsion between the particles, and as a result of this, the suspension becomes more stable. In order to destabilize the colloidal suspension, flocculants are usually added, so that the settling rate of the fine particles also increases. These flocculants are of cationic, anionic and non-anionic depending upon the type of charge released when dispersed in water. The flocculants may act partly for charge neutralization and partly for inter particle bridging and electrostatic patch formation. The effectiveness of any type of flocculants depends upon the molecular weight and charge density of the polymer. The paper discusses the settling behavior of non-coking coal fines suspension by using different flocculants. Keywords: floculent, coal fines, sedimentation rate, effluent

Sep 1, 2012

By Ting An Zhang, Chengzhi Jiang, Xiujing Zhai, Feng Xie

The extraction and concentration of nickel from aqueous solutions by emulsion liquid membranes (ELMs) using tributylphosphate (TBP) as extractant has been investigated in this research. The emulsion liquid membrane consists of a diluent (kerosene), a surfactant (Span 80), a mobile carrier (TBP), and a stripping solution (ammonia solutions). Important factors influencing the separation process including membrane composition, feed composition, and mixing speed have been examined. The results show that more than 90% of nickel in the feed solution could be extracted by ELMs under the experimental conditions, indicating the feasibility to use the designated ELMs to detoxify nickel-containing industrial waste solutions.

Jan 1, 2014

By M. E. Holter

"Three main potash members are recognized within the Prairie Evaporite Formation of Saskatchewan and have been designated, in ascending order, the Esterhazy, Belle Plaine and Patience Lake members. Each is composed of sylvinite near the geographic center of the member and becomes increasingly carnallitic marginally. Each stratigraphically higher member has a narrower carnallitic margin. The sharp contact between carnallitic and non-carnallitic components of the formation describes a surface which may be traced regionally and is not related to bed-ding. The contact rises higher in the stratigraphic section toward margins of members. Within each of the three members, analyses indicate that carnallite becomes more abundant toward the north whereas sylvite and insolubles, increase toward the south. Within each member, areas rich in carnallite are coincident with areas in which the member as a whole is thicker than averag,e. The Belle Plaine Member contains the highest concentrations of carnallite, the Esterhazy the lowest. A maximum content of about 30 per cent sylvite is common to all three members. Insoluble contents increase in successively higher members.Map studies are combined to outline the economic potential of the potash beds in terms of depth to the top of the Prairie Evaporite, ""salt-back"" thicknesses and sylvite grades for each member."

Jan 1, 1971

By H. -P. Behrendt

Muldenhiütten Recycling und Umwelttechnik GmbH is a lead smelter with a very long tradition. The first reference to the existence of smelters on this site is given by a document of inheritance dated 1318. Originally run as a primary lead smelter, which was supplied with ores from the Freiberg mining district and from overseas, it was required to change it over to secondary raw materials due the abandonment of mining in the Freiberg area in 1968. Today, Muldenhüitten Recycling und Umwelttechnik GmbH has two production lines; lead production from secondary lead and waste incineration, which are closely connected and gain advantage from each other. Installations, improved technologies, and the highly skilled personnel have contributed to satisfy all demands for a production concerning quality and environment.

Jan 1, 2000