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Showing 1 to 20 of 121 for “"Chalcopyrite"”.
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Bioleaching of chalcopyrite
… research is concerned with the bioleaching of chalcopyrite (CuFeS\(_2\)) by Thiobacillus ferrooxidans (ATCC 19859), which has been carried out in shake flasks (250 ml) and a 4-litre stirred tank bioreactor. The effects of experimental factors such as initial pH, particle size, pulp density and …
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Modeling chalcopyrite leaching kinetics
Chalcopyrite (CuFeS2) is the most abundant of the copper sulfides and also one of the most refractory for leaching. Several processing routes have been proposed to overcome drawbacks associated with environmental problems related to copper extraction from this mineral. Atmospheric leaching in …
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An investigation into the ferric leaching of chalcopyrite : a sub-process in the bioleaching of chalcopyrite
… Unit is to develop an understanding of the chalcopyrite bioleaching sub-processes. This thesis forms part of the greater study on bioleaching, investigating the ferric leaching subprocess. The objective of this thesis was two-folds. Firstly, a detailed literature review was undertaken to …
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Collectorless flotation of chalcopyrite and sphalerite ores
The flotation of chalcopyrite and sphalerite has been accomplished without the use of collectors. Of the six chalcopyrite ores tested in the present work, some floated well using only a frother, while others required the addition of sodium sulfide, presumably to remove the hydrophilic surface …
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Investigation of Chalcopyrite Leaching Kinetics by Alternative Leaching Chemicals
Chalcopyrite (CuFeS2) is one of the most abundant sulfide minerals in the world copper deposit. It is known as a refractory sulfide mineral due to passivation during leaching process in a conventional leaching system. In this study, alternative lixiviants, MSA (methanesulfonic acid, CH4SO3) and …
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An initial electrochemical study into the (Bio)Leaching of chalcopyrite
… for extraction of metals from mineral ores. Chalcopyrite is a key copper mineral due to its abundance on earth. However, due to its refractory nature in sulfate leaching systems, a viable hydrometallurgical route for its extraction remains elusive...The work in this present thesis is …
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Characterization of industrially processed chalcopyrite solar cells with varied absorber composition
… loss mechanisms in industrially processed chalcopyrite thin film solar cells of the conventional ZnO:Al/i-ZnO/CdS/Cu(In,Ga)(Se,S)2/Mo layer structure investigated. The results of this thesis were obtained within two independent projects with different industry partners each applying …
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Sustainable Mining - Solving the Problem of Chalcopyrite Treatment/Processing - Leaching, Solvent Extraction & Flotation
Chalcopyrite ore forms the significant fraction of copper deposits in the earth crust. However, it is also the most difficult to treat using conventional ferric leaching methods. Smelting and electro-refining are currently the methods used in treating chalcopyrite concentrate obtained from froth …
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Interrelationship of hydrology, microbial colonisation and hydrometallurgy in a simulated chalcopyrite heap leach
Chalcopyrite is the most abundant primary copper sulphide mineral found worldwide. As copper grades of ores available for extraction decrease, heap bioleaching is gaining interest as a potential operating alternative to traditional methods of roasting and smelting. The efficiency by which bacteria …
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Electronic Properties of ALD Zinc Oxide Interfaces and its Implication for Chalcopyrite Absorber Materials
Zinkoxid (ZnO) in seiner Eigenschaft als transparenter elektrischer Leiter wird heute in vielen Anwendungen eingesetzt, beispielsweise als Frontkontakt für Dünnschicht-Solarzellen. Dort wird der Heteroübergang zwischen dem p-dotierten Chalkopyrit Absorber heutzutage noch mit einer dünnen Schicht …
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An investigation into the mechanism of bioleaching of a predominantly-chalcopyrite concentrate with mesophiles
Bioleaching is an established technology for the treatment of refractory gold ores and concentrates. The bioleaching of sulphide minerals is a complex process in which bacterial and chemical oxidation processes occur simultaneously. Recent studies has provided convincing evidence that the …
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An electrochemical and leach study of the oxidative dissolution of chalcopyrite in ammoniacal solutions
Chalcopyrite is not only the most abundant of the copper sulphides, but also the most stable, making it recalcitrant to hydrometallurgical treatment processes especially in atmospheric leaching. Hence, pyrometallurgical processes are traditionally used to treat chalcopyrite concentrates. However, …
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A reconnaissance investigation of chalcopyrite-sphalerite relationships in the Cu-Fe-Zn-S system
… portion containing pyrrhotite, pyrite, bornite, chalcopyrite, cubanite, and sphalerite. Chalcopyrite-sphalerite relationships were emphasized because of their common association as intimately intergrown phases (interpreted as exsolution or replacement) in major Cu-Zn ore bodies. The investigation …
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The effect of particulate-induced hydrodynamic stress on the bioleaching of chalcopyrite by a Sulfolobus sp.
… particularly of recalcitrant minerals such as chalcopyrite. The drawback to using high temperature microbes is that these thermoacidophiles, unlike their mesophilic counterparts, are Gram-negative Archaea, not bacteria, hence they do not possess resilient cell walls and are more prone to …
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Computational modelling of the electronic and structural properties of chalcopyrite-type semiconductors and platinum group metal chalcogenides
… DFT to study the electronic properties of eight chalcopyrite-type semiconductors which are transition-metal type and hence are strongly correlated materials. For our chosen systems we first used the Local Density Approximation (LDA) and Generalized Gradient Approximation (GGA) energy exchange …
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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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Trace element distributions and partitioning trends in hydrothermal base metal sulphide ores comprising sphalerite, galena, chalcopyrite and tetrahedrite-tennantite
… be incorporated into natural sphalerite, galena, chalcopyrite and tetrahedrite-tennantite are determined, as are the preferred equilibrium trace element partitioning trends among these sulphides. The previously documented coupled substitution Ag⁺+(Bi, Sb)³⁺↔2Pb²⁺ in galena is confirmed, yet should …
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Flotation of sulfide minerals with alkyl pyridinium salts
… been used as collectors for the flotation of chalcopyrite and copper-activated sphalerite. For the ores tested in this study, these reagents have demonstrated improved selectivity and recovery in comparison to conventional xanthates. The best flotation results, in terms of both grade and …
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Trace element proxies and mineral indicators of hydrothermal fluid composition and seafloor massive sulfide deposit formation processes
… Ag, and In between hydrothermal vent fluids and chalcopyrite lining fluid conduits in black smoker chimneys. Chapter 3 develops secondary ion mass spectrometry (SIMS) as a technique to measure Co, Ni, Ga, Ag, and In in chalcopyrite and identifies a correlation between Ga and In in chalcopyrite …
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Trace element proxies and mineral indicators of hydrothermal fluid composition and seafloor massive sulfide deposit formation processes
… Ag, and In between hydrothermal vent fluids and chalcopyrite lining fluid conduits in black smoker chimneys. Chapter 3 develops secondary ion mass spectrometry (SIMS) as a technique to measure Co, Ni, Ga, Ag, and In in chalcopyrite and identifies a correlation between Ga and In in chalcopyrite …
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