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Showing 1 to 20 of 36 for “"arsenopyrite"”.
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Kinetics of Arsenopyrite Oxidative Dissolution by Oxygen
… rate and infer potential mechanisms of arsenopyrite (FeAsS) oxidation by dissolved oxygen at 25°C and circumneutral pH. Release rates for iron, arsenic and sulfur are calculated for a variety of initial dissolved oxygen (DO) concentrations. Results indicate that the rate of arsenopyrite …
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Biooxidation of a gold bearing arsenopyrite/pyrite concentrate
… the biooxidation of an auriferous pyrite/arsenopyrite flotation concentrate, and to interpret laboratory batch and continuous pilot plant data in the light of the logistic model. Furthermore, the possibility of predicting continuous biooxidation plant performance from batch data was …
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An Investigation into the bacterial leaching of a gold-bearing pyrite/arsenopyrite ore
… leaching process for a gold-containing pyrite/arsenopyrite ore. The effect of various parameters on, and the mechanism of, bacterial leaching were investigated. Initially milled run-of-mine ore was examined. Batch tests and a continuous bacterial leach were carried out. Bacterial leaching was …
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The oxidation rates of arsenopyrite and chalcopyrite in acidic ferric chloride solutions at 0 to 60°C
The rates of oxidation of arsenopyrite and chalcopyrite by Fe³⁺ at concentrations of 10⁻² to 10⁻⁵ molal with a pH near 2 and temperatures of 0 to 60°C, conditions similar to those found in weathering sulfide ore deposits, have been determined. The rate equations for 25°C are: dn<sub>Fe</sub>3+/dt = …
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Studies on the mechanism and kinetics of bioleaching with special reference to the bioleaching of refractory gold-bearing arsenopyrite
Bioleaching is now an established technology for the leaching of whole-ore copper heaps and the pre-treatment of refractory arsenical gold ores and concentrates. For the case of refractory arsenical gold concentrates, it offers an economically feasible alternative to pressure oxidation and has …
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Assessment of Arsenic Mobility Using Sequential Extraction and Microscopic Methods
… the presence of three arsenic bearing minerals, arsenopyrite, scorodite and arsenic-rich iron oxides, in both sediment and the host rock. In sediment, the minerals are present as individual grains, but in the host rock, they are present together, often with arsenopyrite at the core, surrounded by …
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The kinetics of ferrous iron oxidation by Leptospirillum-like bacteria in absence and in presence of pyrite and pyrite/arsenopyrite mixtures in continous and batch cultures
The leaching process of pyrite and pyrite/arsenopyrite in presence of bacteria is considered a 2-step mechanism, in which i) the mineral sulphide is chemically leached by ferric iron into the metal ion and sulphate and ii) the bacteria regenerate ferric iron. The kinetic parameters of these …
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Arsenic transport in groundwater, surface water, and the hyporheic zone of a mine-influenced stream-aquifer system
… stream-aquifer system influenced by an abandoned arsenopyrite mine. Mine tailing piles consisting of a host of arsenic-bearing minerals including arsenopyrite and scorodite remain adjacent to the stream and represent a continuous source of arsenic. Arsenic loads from the stream, springs, and …
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Changes in water chemistry and fluvial geomorphology from arsenic contaminated floodplains of Whitewood Creek and Belle Fourche River, South Dakota
… Fourche River. The mine waste which contains arsenopyrite and other arsenic bearing minerals, is deposited along the floodplains of Whitewood Creek and the Belle Fourche River as overbank deposits and abandoned meander and channel fill. The introduction of mine tailings into these streams has …
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Weathering of sulfide ores in model soils, potentially toxic element release and bioavailability
… release from grains of sphalerite (Zn(Fe,Cd)S), arsenopyrite (FeAsS) and cinnabar (HgS) into soil matrices (0.1 % mineral:soil m/m), and the bioavailability of the liberated PTEs to important food crops (Tricitum aestivum, wheat and Oryza sativa, rice). All three of the ores underwent chemical …
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A Comparison of Geochemistry, Carbonate Mineralogy, and Argillic Alteration between the Dome Prospect and the Main Au Resource of the Donlin Creek Project in Southwest Alaska
… mineral assemblage is composed of auriferous arsenopyrite-pyrite ± stibnite, realgar, and native arsenic intimately associated with Fe-dolomite. Crystallization of euhedral arsenopyrite on porous pyrite-marcasite ± pyrrhotite grain boundaries, mainly in the resource area, demonstrates the late …
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Geology and isotope geochemistry of the Beaver-Temiskaming Silver Mine, Cobalt, Ontario
… (oxygen isotopes in silicates), 211-258°C (arsenopyrite composition) and 130-227°C (coexisting sulphides). Carbonate isotopic data were reset by meteoric water. Connate waters, interpreted from fluid inclusion data, equilibrated with Archean sulphide-rich interflow units and overlying …
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Mineralization and Wall Rock Alteration Flin Flon area, Saskatchewan
… veins, (3) quartz-sulphide veins, and (4) quartz-arsenopyrite veins. One copper deposit was studied and it was classed as a sulphide replacement deposit. The mineralization occurs along fissures in volcanic rocks of the Amisk group and in post-Missi intrusions. The minerals were deposited from …
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Paragenetic Evolution of the Robertson Deposit: Eocene Intrusion Related Gold Deposit in the Northern Shoshone Range, Nevada
… biotite veinlets and quartz-K-feldspar, quartz - arsenopyrite, quartz - chalcopyrite, and quartz - molybdenite veins. The syn-gold stage is composed of quartz - gold ± Bi-Te-Se-Pb-Ag-S sulfosalt veins, consisting of native gold seen as single grains in quartz gangue and/or on the surface of …
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Sulphide ore minerals:surface chemical properties
… ((FeiNi)9Se), chalcopyrite (CuFeS2) and arsenopyrite (FeAsS). The surfaces were oxidised by various methods including acid (sulphuric), alkali (ammonium hydroxide), hydrogen peroxide, steam, electrochemical and air/oxygen (in a low-temperature (150ºC) furnace), The surfaces were examined …
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Geochemistry and origin of the Asimotrypes carbonate hosted mesothermal gold deposit, Pangeon mountain, N. Greece
… and shear-zone style consists mainly of arsenopyrite, pyrite and gold, with subordinate sphalerite, galena, chalcopyrite, pyrrhotite, tetrahedrite-tennantite, marcasite, covellite and malachite. Gold is either refractory occurring mainly in arsenopyrite and to a lesser extent in Aspyrite, …
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Environmental mineralogy of gold recovery from refractory gold-arsenic-bearing Bakyrchik concentrates
… the world. Gold (Au) is dispersed in pyrite and arsenopyrite in the form of microscopic inclusions. Despite the fact that only 10% of gold ore has been mined to date, it has left behind a dangerous As-containing legacy. Speciation of As has been determined for samples from Bakyrchik to understand …
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Characterization and prediction of long-term arsenic mobility, dissolution, and kinetic behavior in arsenic contaminated floodplain deposits of Whitewood Creek and the Belle Fourche River, South Dakota
… which joins the Belle Fourche River (BFR). Arsenopyrite and other arsenic-bearing minerals were deposited in tailings (containing between 0.12% to 0.35% arsenic) and mixed with uncontaminated alluvium along the floodplains of WWC and the BFR as overbank deposits and filling abandoned …
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Ore mineralogy and paragenesis of a portion of the Great Gossan Lead district, Virginia
… and chalcopyrite. All other phases--galena, arsenopyrite, pyrite, cubanite, mackinawite, tetrahedrite, stannite, and native bismuth--are disseminated throughout the ores. Pyrite is locally common as corroded primary euhedrae in some are bodies. Sphalerite occurs as disseminated anhedral …
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Intensive parameters of a sulfide and aluminosilicate-bearing granite, Hancock County, Maine
… of 1) sulfides (pyrrhotite, pyrite, loellingite, arsenopyrite, chalcopyrite, and sphalerite) 2) volatile-rich phases such as muscovite, tourmaline, apatite, and chlorite, and 3) high-temperature anhydrous phases such as andalusite and fibrolite. Feldspars have been partially altered to muscovite, …
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