The basis for reevaluating the reactivity of pyrite surfaces: …
Pyrite, one of the most important minerals to catalyze redox reactions in nature and a bulk low-spin Fe mineral, needs to provide high-spin Fe on surfaces to moderate spin-forbidden transitions. Here, the spin state of pyrite is investigated using density functional theory (DFT) calculations on cluster and p
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Fine Coal Flotation in a Centrifugal Field
Two batches of ore, A and B, from the reclaimed dumps of ERGO Ltd on the East Witwatersrand were used to investigate the effect of design parameters on the flotation of …
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High Centrifugal Force
After a short time the lighter heavies (e.g. pyrite) begin to experience significant erosion from the top of the concentrate bed, and build up takes place of some high-density minerals and tramp iron. ... Here, larger and/or denser particles sediment more rapidly in the centrifugal field and thus form a pellet on the wall or floor of the rotor ...
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Understanding the Surfaces and Crystal Growth of …
The geological pyrite presents different morphologies depending on the growth conditions, i.e. the temperature, the Fe and S contents of the solution, adsorbed species. The most common forms of pyrite are cubic (with 6 {100} facets), …
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Environmental-sulfur-controlled surface properties of pyrite…
These findings reveal the nature of pyrite surfaces in various sulfur conditions, proving fundamental not only for surface-related applications but also for geological indicators of pyrite formation conditions.
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First-principles electronic structure and relative stability of …
Despite the many advantages (e.g., suitable band gap, exceptional optical absorptivity, earth abundance) of pyrite as a photovoltaic material, its low open-circuit voltage …
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An overview of operating parameters and conditions in
Over the past century, the development and use of centrifugal inertial force fields have greatly improved separation efficiency, and meanwhile, reduced the equipment footprint and operating costs ...
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Centrifugal Field
Centrifugal Field + French database ID. 6,271 + French lore. Lorsqu'un Monstre de Fusion est détruit par l'effet d'une carte et envoyé dans le Cimetière, sélectionnez 1 des Monstres-Matériel de Fusion inscrits sur la carte du …
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First-principles electronic structure and relative stability …
the pyrite structure can be viewed as a slight modification of the NaCl structure, such that each Cl site is occupied by h111i-oriented S 2 dumbbells. It is well-known from …
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Fine Coal Flotation In A Centrifugal Field With An Air …
With regard to processing technology, about 50% of the 800x106 tons of coal mined annually in the U.S. is processed in preparation plants. The purpose of the physical separations accomplished in these preparation plants is to remove ash (present as clays and other oxide minerals) and sulfur 'present mostly as pyrite).
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Environmental-sulfur-controlled surface properties of pyrite: …
These findings reveal the nature of pyrite surfaces in various sulfur conditions, proving fundamental not only for surface-related applications but also for geological indicators …
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Bubble generation in swirl flow during air-sparged …
capacity for fine-particle flotation in a centrifugal field. For example, it is now evident that the ASH has a specific capacity of at least 100 times that of conventional flotation equipment. During the 1980s, small 2~in.-diam ASH units were tested for a large number of mineral commodities, and
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Understanding the Surfaces and Crystal Growth of Pyrite FeS 2
The geological pyrite presents different morphologies depending on the growth conditions, i.e. the temperature, the Fe and S contents of the solution, adsorbed species. The most common forms of pyrite are cubic (with 6 {100} facets), octahedral (with 8 {100} facets), and pyritohedral with 12 distorted pentagonal facets.
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Mechanisms and rates of pyrite formation from hydrothermal fluid
Our experiments simulate in-situ pyrite precipitation from hydrothermal fluids at 400–450 °C. Theoretical β-factors of minerals and aqueous species constrain equilibrium isotope fractionation. Aqueous Fe (II)- (poly)sulfide species control …
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First-principles electronic structure and relative stability …
the pyrite structure can be viewed as a slight modification of the NaCl structure, such that each Cl site is occupied by h111i-oriented S 2 dumbbells. It is well-known from crystal field theory that the energies of transition metal d orbitals are non-degenerate within
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Evaluation of the Efficiency of Using an Oxidizer in the …
This article presents the results of cyanide leaching of gold-containing concentrate using the trichlorocyanuric acid (TCCA) oxidizer. Gold-containing concentrate was obtained from a gold tailings sample from a gold recovery factory (GRF) in one of the deposits of Kazakhstan that have not previously been studied for concentrability. According to X-ray phase analysis …
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A novel method for purification of low grade diatomite …
The grade of diatomite was further improved due to the remarkable difference of particle density and size in the centrifugal field. 4. ... Effect of sodium hexametaphosphate on separation of serpentine from pyrite. Trans. Nonferrous Met. Soc. China, 21 (2011), pp. 208-213. View PDF View article View in Scopus Google Scholar. Şan and İmaretli ...
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Dry separation of pyrite from coal. [Centrifugal and …
Search 219,231,652 papers from all fields of science. Search. Sign In Create Free Account. ... {Abel1971DrySO, title={Dry separation of pyrite from coal. [Centrifugal and electrostatic methods; restriction of particle-size range benefits both methods; pyrite particles should be as large as possible]}, author={W. T. Abel and M. Zulkoski and G. J ...
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Application of the Falcon Concentrator for fine coal cleaning
Therefore, the ability of pre-combustion cleaning technologies to reject coal pyrite as well as other toxic elements may decide the fate of many mines extracting medium-to-high sulfur coal. Presently, physical cleaning methods are considered to be the only economical means by which fine coal can be treated. ... However, the larger centrifugal ...
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How to Remove Pyrite from Coal
The two pyrite-separation methods (centrifugal and electrostatic) that constitute the dry process supplement each other beneficially. By removing most of the lightweight, pyrite-depleted portion in the centrifugal step, electrostatic separation of pyrite from the remaining pyrite-enriched heavy portion is more effective.
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First-principles electronic structure and relative stability of pyrite …
Despite the many advantages (e.g., suitable band gap, exceptional optical absorptivity, earth abundance) of pyrite as a photovoltaic material, its low open-circuit voltage (OCV) has remained the biggest challenge preventing its use in practical devices.
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Mechanisms and rates of pyrite formation from …
Our experiments simulate in-situ pyrite precipitation from hydrothermal fluids at 400–450 °C. Theoretical β-factors of minerals and aqueous species constrain equilibrium …
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CFD-DEM simulations of particle separation characteristic in
The separation of particles in centrifugal compounding force field is complex due to the interaction of centrifugal force, viscous drag force, inter-particle contact force and particle-particle ...
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Trace element evidence for diverse origins of superheavy pyrite …
Here, we trained two supervised machine learning algorithms on a large LA-ICP-MS pyrite trace element database to distinguish pyrite of different origins. The analysis validates that two models built on the co-behavior of 12 trace elements (Co, Ni, Cu, Zn, As, Mo, Ag, Sb, Te, Au, Tl, and Pb) can be used to accurately predict pyrite origins.
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The basis for reevaluating the reactivity of pyrite surfaces: …
Pyrite, one of the most important minerals to catalyze redox reactions in nature and a bulk low-spin Fe mineral, needs to provide high-spin Fe on surfaces to moderate spin …
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Centrifugal field Definition & Meaning
The meaning of CENTRIFUGAL FIELD is a space in which centrifugal forces may be detected (as in a rotating centrifuge or in a vehicle rounding a curve).
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High gradient magnetic separation in centrifugal field
As one of the most effective techniques for fine particle processing, high gradient magnetic separation is mainly used in the separation and enrichment of fine and weak magnetic particles and other… Settling behaviour of particles in aqueous mediums depends on the resultant force acting on them.
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Photomicrograph, enlarged to show centrifugal replacement of pyrite
Album caption and index card: Photomicrograph of part of field shown photo 728, enlarged to show centrifugal replacement of pyrite (p) by sphalerite (s). Chalcopyrite (c) replaces sphalerite in small irregular veinlets. q, Quartz. Boulder County, Colorado. Notes: Published as figure LXVIII-C in U.S.Geological Survey. Professional Paper 223. 1950.
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Trace element evidence for diverse origins of superheavy …
Here, we trained two supervised machine learning algorithms on a large LA-ICP-MS pyrite trace element database to distinguish pyrite of different origins. The analysis validates …
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Fine Coal Flotation in a Centrifugal Field
Centrifugal fields can be generated either by mechanically rotating devices such as centrifuges or by conversion of pressure head into rotational motion as found in hydrocyclones.
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