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By R. H. Matjie, J. R. Bunt, A. C. Collins, J. C. van Dyk, C. A. Strydom

South African coal discards derived from feed coal for thermoprocesses pose human health and environmental problems and incur high disposal costs. These issues need to be resolved. Coal fines and a coal fines/ K2CO3 blend were combusted at 700°C in a laboratory rotary kiln to produce ashes containing metakaolinite (Al2O3.2SiO2) and illite/muscovite/orthoclase amorphous materials. The blend ash and coal fines ash, containing 18% K2O and <1% K2O respectively, were leached with water and with 1 M and 8 M NaOH at 80°C for 4 hours using a solid to liquid ratio of 1:5. The 8 M NaOH leach yielded 17% sodalite (Na8Si6Al6O24(OH)2) formation through SiO32-, Al(OH)4-, and Na+ precipitation in the leached ashes. The 1 M NaOH leach yielded no sodalite. X-ray fluorescence analysis of the original ashes and leached ashes showed low Al and Si dissolution efficiencies due to the sodalite formation. Sequential NaOH leaching resulted in the highest potassium dissolution efficiency of 89% for the ashes of fines/K2CO3 blend and 59% for the fines. It may be possible to increase the ash-derived zeolite concentration by using even higher NaOH concentrations (12–20 M NaOH) during leaching. Sodalite derived from coal ash could possibly be utilized for water purification in industrial applications, or as molecule separators. The potassium-containing liquid could be used in fertilizer manufacture.

Mar 30, 2023

By José Fernandes De Oliveira Ugarte

El presente texto describe los resultados de la caracterización mineralógica de muestras minerales de cobre que fueron empleados en el proceso de flotación. Para este proceso, fue necesario conocer la mineralogía de diferentes minerales de cobre de yacimientos tipo pórfido, así como sus asociaciones con los estudios mineralógicos y estudios geoestadísticos por microscopia electrónica de barrido con el sistema de energía dispersiva.

Feb 1, 2014

Prof. J. C. BRanner, Stanford University, Cal. (communication to the Secretary): On p. 398, Mr. Hedburg mentions Marionite and Brannerite as ores of zinc. Neither of these has been authoritatively recognized as a distinct mineral species. Marionite, originally described by Elderhorst, was subsequently determined to be nothing else than hydrozincite. Analyses of the so-called Brannerite were sent by me to Prof. Penfield, who says it is a mixture of Smithsonite with some other mineral. On p. 398, Mr. Hedburg says the zinc-bearing formation of North Arkansas " is recognized as the Upper Silurian." So far as my observation goes, the ores occur both in Lower Carboniferous and in Ordovician or Lower Silurian rocks, but nowhere in rocks known to be of Upper Silurian age. If Mr. Hedburg has any paleontological evidence of the Upper Silurian age of these rocks, or of any of them, he will confer a favor upon geologists by making it known. On the same page is another statement in which I cannot concur. He says that in this region, " it can easily be seen that the largest fissure-deposits have been eroded and washed away, leaving here and there a few patches adhering to the hillsides." I am compelled to say that in many years&apos; study of the geology of the region in question, I have never been able to recognize such a state of affairs as Mr. Hedburg here describes. The patches which he regards as remnants of fissure-veins, " adhering to the hillsides," I have found to be either the edges of bedded deposits, or portions of the zinc-bearing breccias, formed along old drainage-lines, and laid bare by the ordinary processes of erosion. That fissure-deposits have been partly removed by the same agency, goes without saying; but it is, in ,my judgment, no more true of North Arkansas than of any other mining-region that erosion has selected and washed away " the largest " deposits. My own views of the region in question are given in detail

Jan 1, 1902

By Manuel Gomez

The mean and the standard deviation were used to describe general sulfur and ash populations as well as specific populations of these variables from one coal seam. Both the mean and the standard deviation were incorporated in the exploration process to determine the number of drill cores necessary for seam evaluation and to guide the sequential drilling plan. Probability regions were computed to establish a basis for predicting probable ranges of average sulfur and ash concentrations that may be expected upon continued or future drilling. A computerized plot program was utilized to interpolate sulfur and ash concentrations between grid points. The plot program, which is essentially a moving average technique, permits a rapid evaluation of sulfur, sulfur forms, and ash spatial distributions as a drilling program progresses sequentially. This information, in the form of contour plots, can be made available to both the mining engineer and the fuel technologist in advance of mining to outline reserves, to improve selective mining, and to anticipate preparation facilities.

Jan 1, 1972

By A. C. Headon, K. W. Lam, D. P. Dautovich

"Microbiological activities affecting the performance of materials have been encountered in diverse situations within Ontario Hydro. Case histories of bacterial problems which are presented include ground rod corrosion at transformer stations, corrosion of a bare steel cooling water intake structure in Lake Huron and corrosion of steel components in a nuclear generation station vacuum building. Possible microbiological activities which may affect the corrosion behaviour of containers for the disposal of nuclear fuel waste in the future are discussed, as are bacterial actions suspected of causing an odour problem in residential water heaters.IntroductionBacteria are ubiquitous. Except by use of sterilization methods, bacteria -free environments are no t possible to find. Bacteria lie dormant in hostile environments, spread easily through air and water currents and reproduce rapidly under favourable conditions. Although different types of bacteria have different preferable conditions for growth, they are highly adaptive and in general, whenever there is a source of water and carbon (carbon dioxide or organic matter), there will be bacterial activities . These activities often induce or enhance costly metallic corrosion in industries and water odour problems in rural water supplies . Underground structures and systems in contact with natural water or water containing organic matter are most susceptible to bacterial attack.The types of metal-degrading bacteria , their characteristics and the conditions for growth have been reviewed extensively in the literature(1,2,3). There are several often encountered groups of bacteria which, through their metabolic processes, may lead to the degradation of metals. A large variety of bacteria produce corrosive in organic or organic acids as waste, such as the well known formation of sulphuric ac id by aerobic sulphur oxidizers . Anaerobic sulphate reducers produce hydrogen sulphide which is corrosive and has an obnoxious smell, slime-forming bacteria from slime which shelters sulphate reducers and iron bacteria oxidize ferrous to ferric ion which precipitates as hydrated oxides creating oxygen concentration cells . The following are bacterial problems encountered in Ontario Hydro. Although the number of recognized cases has been few, they show the diversity of location and environment where bacterial problems could arise. These include ground rod corrosion at transformer stations, corrosion of bare steel in a water intake structure, corrosion of steel in a nuclear generation station vacuum building and an odour problem in residential hot water tanks. In addition, possible bacterial- enhanced corrosion in containers for future disposal of nuclear fuel wastes are also discussed."

Jan 1, 1984

By Romeo Calderón

El presente trabajo describe los trabajados realizados en la Compañía minera Huarón con el objetivo de realizar la explotación de vetas muy angostas y sinuosas de potencias inferiores a 1.20 m. de un modo seguro, eficiente y económico, donde fue necesario resolver el problema de carguío y acarreo en tajeos inferiores a 1.20 m. empleando equipo LHD de 0.80 m. de ancho, fabricado especialmente para este fin.

Nov 1, 1982

By Robert Rhea Goodrich

This research was done partly in the non-ferrous laboratory of the Department of Metallurgy of Columbia University, under the direction of Dr. Edward I?. Kern, and completed elsewhere. Acknowledgment is due to Prof. Arthur L. Walker, Dr. Edward F. Kern and Dr. William Campbell of the Department of Metallurgy, for their kind advice and for the inspiration derived from their instruction. This report is given under the following heads: Petrographic Description (Microscopic Study); Sampling and Preparing Ore for Treatment; Chemical Analysis; Treatment of Ore. Petrogeaphic DescRiption Texture: variable. Fine to medium mixed aggregate. Original Structure: Obscurc. Secondary structure: Fractured; healed. Mineralogy (Minerds are grouped for interpretation purposes and are arranged, in each group in approximate order of abundance)

Jan 1, 1916

By Jae-Chun Lee, Rajiv Ranjan Srivastava, Min-seuk Kim, Byung-Su Kim

Recycling of spent hydrotreating catalysts (HTC) can potentially contribute towards the sustainable extraction of metal values. Treating such materials by hydrometallurgical methods to separate metals from the leach liquor of either acid/alkali media is a major step. In the present study, separation of molybdenum from HCl leach liquor of spent NiMo type HTC has been investigated by applying solvent extraction using Cyanex-923. For this, the chloride solution containing 973 mg/L Mo, 254 mg/L Ni and 1634 mg/L Al was taken as the aqueous feed. The parameters including contact time, concentration of the extractant, acid and chloride, and phase ratio were varied to investigate their effect on the extraction efficiency. The McCabe-Thiele plot suggests that > 99% Mo-loading using a 2-stage extraction process. From the molybdenum depleted solution, nickel was selectively extracted by Cyanex-301 leaving Al in the raffinate.

Jan 1, 2014

By Augusto Andrés Torres Toledo

Na mineração a céu aberto, na etapa de planejamento a curto prazo são desenhados constantemente polígonos usados no planejamento de produção, onde geralmente o processo de desenho é manual, demandando o tempo e esforço dos planejadores. Os polígonos gerados no planejamento de curto prazo devem apresentar a menor variabilidade possível entre eles, para que as restrições da planta de processamento sejam atendidas. Desenhar polígonos de curto prazo de forma automática, sequenciar todos os blocos de minério em cada polígono, e conectar um polígono a outro é o foco deste trabalho. Para isso, foi feito uso de algoritmos genéticos e dinâmicos, desenvolvidos em linguagem de programação Python e operacionalizados no software geoestatístico SGeMS. Gerou-se múltiplas iterações para cada um dos avanços individuais de blocos de minério, gerando regiões ou polígonos, e selecionando as regiões de menor variabilidade de teores. As funções de distribuição de probabilade dos teores de cada avanço foram comparadas a função da distribuição de teores global do corpo de minério, os resultados mostram que os polígonos possuem distribuições semelhantes à distribuição de referência, então foi possível sequenciar os blocos de forma operacional garantindo quasi-estacionaridade dos parâmetros.

Oct 30, 2017

By W. G. Davenport

A survey of world copper refining tankhouse .practices has been carried out. This paper compiles the results and examines changes in operating practices .since the similar 1987, 1991 and 1995 surveys. Continuing trends are the installation of ISA Process and Kidd Process stainless steel cathode technology, polymer concrete cells, anode preparation machines and automatic cranes. Instrumentation and automatic control are increasing, particularly for addition agent optimization; solvent extraction .and ion exchange techniques are being increasingly applied for electrolyte purification. The overall consequences of these changes have been &apos;improved cathode purities and enhanced tankhouse productivities.

Jan 1, 1999

By R. V. Higgins

This report presents the results of a study of gas injection in the Upper and Lower Terminal zones in fault block VB and in the Upper Terminal zone in fault block VI, Wilmington field, California. This report is based on data obtained to January 1956. Earlier studies of gas injection in other California fields have been reported .3/ The Upper and Lower Terminal zones, fault block VB, have been producing oil since 1945 and the Upper Terminal zone, fault block VI, since 1948. Before starting the gas-injection project, the expansion of dissolved gas was the principal mechanism moving the oil to the wells. Gravity drainage and an edgewater drive also have contributed to the movement of the oil to the wells. When the gas injection was begun, the reservoir pressure and the oil production had declined appreciably. Gas injection was started in the Upper and Lower Terminal zones, fault block VB, in May 1953 and in the Upper Terminal zone, fault block VI, in October 1953.

Jan 1, 1957

By J. W. Horne, W. B. Shirey

"INTRODUCTION The United States Bureau of Mines in cooperation with the State of Colorado at the University of Colorado has conducted experiments to determine the amount and composition of the noncondensable gases evolved when crude shale oil is distilled under pressure.Hydrogen sulphide is one of the components found in the complex mixture of gases produced by the distillation of shale oil under pressure. This paper deals with the apparatus and method used in determining the amount of hydrogen sulphide evolved in the laboratory experimental cracking stills.The study required a complete extraction of all the hydrogen sulphide from the gas stream after it left the water-cooled distillate condensers and before the as stream entered the charcoal absorber for removing the light naphtha. In devising the method it was necessary to take into account a constant variation of velocity, pressure, and percentage of sulphide in the total gas stream coming from the still.Ordinarily, the quantitative determination of hydrogen sulphide in Gas is made by analyzing small samples taken at regular intervals. This estimation can be accomplished by use of the Bunte gas burette as modified by Tutriler,4 or by a similar method. In the industries where the flow of as is constant end of uniform composition, this practice is sufficiently accurate for plant control. For experimental work where many variables have to be taken into consideration, as in the case at hand, these methods are not applicable."

Oct 1, 1931

By S. W. Marcuson

In the late 1960&apos;s concerns about the natural environment reached high levels within North America and provided activists with suitable platforms for exerting influence over the general public and politicians. In response a host of regulatory mechanisms were developed, statutes, voluntary measures, land grants, codes of practices etc. Emerging environmental awareness from the era provided impetus for rapid technological change that encompassed all industries, especially the base metal business. The resulting clean up impacted all aspects of copper production, dealing with issues such as waste disposal, water and air quality with specific impact on emissions of sulfur dioxide and particulate. This paper provides a perspective of these changes reviewing the macro-economic impact of environmental movement in mining with its specific implications to the copper smelting industry. The fundamental challenges that were faced by the old, but capital-intensive North American plants and the approaches taken to deal with the changing times are reviewed with special emphasis on the conceptual approach to smelter S02 abatement and different paths taken in the USA and Canada. The role of economics, sustainable R&D and presence of technical infrastructure that facilitated the change process is elucidated, and speculations are made about the future state of pyrometallurgy and the natural environment. Cu2007 -

Jan 1, 2007

By E. S. Machlin

THE function of this paper is to present certain results based on the fact that the strain energy arising from the solution of out-of-size solute atoms into the solid matrix is free energy and not internal energy, and that this strain energy is almost wholly shear strain energy as Zener1 pointed out. One natural consequence of this fact is an expression for the excess entropy of mixing due to the strain energy. Also, a derivation of the integral molar free energy of mixing partitioned to strain energy will be made using the model of Lawson2 and thermodynamics. This derivation has the advantage of showing in a simple way the assumptions involved in Lawson&apos;s treatment. The excess entropy of mixing partitioned to strain energy can be derived in two ways. The first way makes use of the fact that the strain energy is almost wholly in the form of shear strain energy. In this case, as Zener1 pointed out, the change in entropy due to the addition of shear strain energy is to a first approximation given by ?S/?? p,T = - ?lnµ/?T p,? Hence, the excess entropy of mixing partitioned to strain energy will be given by Sx ? = ?S/?? p,T Gx ? = - ?lnµ/?T p,? Gx ? where, Gx ? is the relative integral molar free en- ergy partitioned to strain energy; S is the entropy; is the shear strain energy; µ is the shear modulus; T is the absolute temperature; p is the pressure; and ? is the shear strain. Zener,1 as well as others, has pointed out that the shear strain energy stored in a compressible isotropic solid due to the insertion of an off-size incompres-sible sphere into a spherical hole in the solid, is approximately given by 2/3 µ/O (O°I - O)2 where a is the volume of spherical hole and no , is the volume of sphere. If we now consider the introduction of one mol of such spheres into an infinite volume of solid, then the relative partial molar free energy excess due to strain energy alone is GM ? = 2/3 µ/v (v ° 1 - v)2 where v is the molar volume of solvent and v°1, is the molar volume of pure solute type 1. Let us consider that these spheres are the two types of atoms in a binary solution, then there will be a similar relation for solute 2. The total relative integral molar free energy excess due to strain is then, to the approximations stated above GM ? = GM ? x1 + GM2 ? x2 = 2/3 µ/v [(v ° 1 - v)2 x1 + (v ° 1 - v)2 x2]. Lawson&apos;s relation for the strain energy can be de-

Jan 1, 1955

By Cyril Stanley Smith

For many years sulphur and its congeners selenium and tellurium have been regarded as very harmful elements in copper and copper-rich alloys. Like many similar prejudices, this has been found to be partly wrong. All three of these elements actually have no great effect on the working properties of copper and its alloys, and are desirable additions in that they considerably enhance the machinability of alloys in which they are present. Because of their possible commercial importance, a study of the machinability and other properties of the pure binary alloys was made, as described in this paper, and the effect of selenium on a large number of copper alloys was determined. The current opinion regarding the deleterious effects of elements in this group undoubtedly arose because of occasional failures of tough-pitch copper containing unusually high tellurium, and because of the well-known fact that sulphur causes spewing and unsoundness in tough-pitch copper. Siebe,1 also Deretchey and Margolina,2 studied the effect of sulphur on copper and showed that in the absence of oxygen it was present in the form of copper sulphide, which was less harmful to the properties than an equivalent amount of copper oxide. No data have been published on selenium and tellurium, although the statement is often made, following Eggleston,3 that tellurium makes copper hot-short. Copper specifications call for only traces of these elements. Skowronski and Mosher4 give data on the effect of selenium and tellurium on the conductivity of tough-pitch copper. In private communication Mr. Skowronski says that the samples were hot-forged from small castings and drawn to 0.081 in. diameter, but it should not be inferred from this that these elements are harmless to the working properties of wirebars and commercial shapes. Constitution and Microstructure Constitution.—Sulphur, selenium and tellurium exist in their alloys with copper in the form of copper sulphide, selenide or telluride. These compounds are practically insoluble in the solid state and possess limited

Jan 1, 1938

By Cyril Stanley Smith

For many years sulphur and its congeners selenium and tellurium have been regarded as very harmful elements in copper and copper-rich alloys. Like many similar prejudices, this has been found to be partly wrong. All three of these elements actually have no great effect on the working properties of copper and its alloys, and are desirable additions in that they considerably enhance the machinability of alloys in which they are present. Because of their possible commercial importance, a study of the machinability and other properties of the pure binary alloys was made, as described in this paper, and the effect of selenium on a large number of copper alloys was determined. The current opinion regarding the deleterious effects of elements in this group undoubtedly arose because of occasional failures of tough-pitch copper containing unusually high tellurium, and because of the well-known fact that sulphur causes spewing and unsoundness in tough-pitch copper. Siebe,1 also Deretchey and Margolina,2 studied the effect of sulphur on copper and showed that in the absence of oxygen it was present in the form of copper sulphide, which was less harmful to the properties than an equivalent amount of copper oxide. No data have been published on selenium and tellurium, although the statement is often made, following Eggleston,3 that tellurium makes copper hot-short. Copper specifications call for only traces of these elements. Skowronski and Mosher4 give data on the effect of selenium and tellurium on the conductivity of tough-pitch copper. In private communication Mr. Skowronski says that the samples were hot-forged from small castings and drawn to 0.081 in. diameter, but it should not be inferred from this that these elements are harmless to the working properties of wirebars and commercial shapes. Constitution and Microstructure Constitution.—Sulphur, selenium and tellurium exist in their alloys with copper in the form of copper sulphide, selenide or telluride. These compounds are practically insoluble in the solid state and possess limited

Jan 1, 1938

By Helênio Resende Silva Júnior, Thiago de Oliveira Mazzeu

O envelhecimento gradual das Baterias de Coque é um fato inevitável, sendo importante monitorar as condições dos fornos e das estruturas periféricas para maximizar sua vida útil. A Paul Wurth desenvolveu uma metodologia de diagnose que avalia as condições dos elementos principais que compõem as plantas de Coqueria, dentre elas: estrutura da alvenaria refratária, estruturas e componentes metálicos, análise do controle térmico e regime de pressões, conjunto das máquinas móveis. Através de inspeções visuais e coleta de informações de processo e rotina adotada pela equipe de preservação da planta de Coqueria, são elaborados procedimentos e recomendações que visam à extensão da vida útil do equipamento. A Diagnose é uma técnica que auxilia as equipes de Coqueria a entenderem em que situação o equipamento se encontra e contribui com as melhores práticas adotadas no mercado para o prolongamento da vida útil. Ela deve ser repetida com frequência de modo a atualizar a situação da Bateria de Coque, verificar o efeito das ações tomadas pela equipe de preservação e propor novas recomendações. A Diagnose ainda permite identificar a idade real de desgaste das estruturas da Bateria em comparação com sua idade cronológica, permitindo que as usinas planejem investimentos de maior porte.

Oct 1, 2019

By S. W. Asihene, K. Osseo-Asare

The thermodynamic data necessary for the quantitative treatment of Metal-NH3- H2O systems at elevated temperatures are lacking in the literature. As a result discussions of the chemical basis of high temperature processes, such as leaching and hydrogen reduction, have tended to rely on low temperature thermodynamic data. In this paper a critical review is presented of the available high temperature data for metal ammine formation in aqueous systems, and methods are suggested to enable extrapolation of elevated temperature stability constants from low temperature thermodynamic data. Predictions of the Van&apos;t Hoff Lsobar, the simple cation Correspondence Principle (whereby metal ammine complexes are treated as simple cations) and Helgeson&apos;s Electrostatic-Nonelectrostatic Model are compared with the available high temperature stability constants for nickel ammines. Up to 80 °C all three estimation methods yield results which are in agreement with experimental data. However, serious deviations occur at higher temperatures; the various models overestimate the stability constants in the order Van&apos;t Hoff Isobar > electrostatic-nonelectrostatic model > simple cation Correspondence Principle. Using the experimental nickel data as a basis, a method is presented which permits reasonable estimates to be made of the stability constants of metal ammine complexes for temperatures above 80 °C.

Jan 1, 2004

By Juan Anes, Omar Godínez, Adrián Tolentino, Mario Franco

Como aplicación práctica de las herramientas hidrodinámicas de flotación desarrolladas por Flottec, McGill y otros investigadores, el objetivo del estudio fue crear, para Minera Fresnillo, una herramienta preliminar de control de procesos, a nivel de la primera celda de la flotación primaria del circuito de plomo, con el fin de expandirla luego a toda la planta. El trabajo determinó ecuaciones matemáticas que describen las relaciones entre las variables de proceso e hidrodinámicas para aumentar la recuperación de plata mientras que disminuye la cantidad de insoluble al concentrado. Se desarrolló usando diseño de experimentos con tres variables (nivel de espuma, adición de espumante en ppm, y flujo de aire en cm/s) para observar los cambios en la recuperación de plata y plomo.

Sep 20, 2019

By L. M. Sun

Baotou Baiyunerbo Mines Location in Inner Mongolia is a famous deposit of iron mineral and rare earth mineral accreting. The iron ore has very complicated ingredients and minerals composing. In the mine, there is not only magnetite ore but also hematite ore, so that it is impossible for high grade iron concentrate to adopt single wet low-intensity magnetic separation or high-intensity magnetic separation to concentrate iron mineral. Because of mixing the magnetite with hematite mineral in feed ore, recovery of iron of magnetite production system in the mineral processing plant is less than other mineral processing plants. Therefore, the research for increasing recovery of iron of the magnetite production system in the plant was undertaken. The paper presented the research for using dry magnetic separation to increase recovery of iron concentrate of the magnetite production system in the plant. It mainly includes dry magnetic separation test and wet magnetic separation and reverse flotation test. The test results indicated that dry magnetic separation is a important way to improve the feature of feed ore of the magnetite production system and to increase the recovery of iron. The recovery of iron may increase from about 70% to over 80%. The research also presented optimum operation parameters of the dry magnetic separator and the separation flowsheet. In conclusion, using dry magnetic separation to treat with feed ore of the magnetite production system in the plant to increase the recovery of iron is a feasible technique. The research present a new way for the mineral processing plant to made technology innovate to increase the recovery of iron concentrate of the plant in future.

Jan 1, 2014