Covellinisation of copper sulphide minerals under pressure leaching conditions

Muszer, Antoni; Wódka, Jerzy; Chmielewski, Tomasz; Matuska, Sabina

doi:10.1016/j.hydromet.2013.03.010

Cited by 25 publications

(11 citation statements)

References 9 publications

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“…and, in the presence of copper ions by a reaction such as CuFeS 2 + Cu 2+ = 2CuS + Fe 2+ (3) Reaction (3) is similar to the well-known conversion of chalcopyrite that has been observed (Bartlett, 1992) at elevated temperatures and recently referred to as "covellinisation" (Muszer et al, 2013).…”

Section: Introductionmentioning

confidence: 86%

The anodic behaviour of chalcopyrite in chloride solutions: Potentiostatic measurements

Nicol

Zhang

2017

Hydrometallurgy

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This paper summarizes the results of the first part of an electrochemical study of the anodic characteristics of chalcopyrite in the potential region relevant to ambient temperature heap leaching in chloride solutions during which both iron(II) and copper(II) act as oxidants for the mineral. Mixed potential (E m) measurements in concentrated chloride solutions in the presence of iron(II) or copper(II) have enabled the potential region of 0.65 V to 0.8 V to be defined as important in the leaching process. The systematic variations in E m with pH and oxidant concentrations suggest that increases in both should result in increased rates of dissolution. This conclusion is also supported by simultaneous decreasing solution potentials due to reduction of the oxidants on the dissolving mineral surface. Slower rates of dissolution can be expected for iron(II) than copper(II) as the oxidant. Potentiostatic measurements at various potentials in the above range at different pH values have confirmed that chalcopyrite undergoes a slow "passivation" that is not complete even after 24 hours. The current densities after prolonged oxidation vary exponentially with potential and increase with increasing pH but are not affected by the concentration of chloride in the range 1-5 M. Measurements with chalcopyrite samples from 3 different locations showed only minor variations in anodic reactivity. Analysis of both the current-time transients and the re-activation of the mineral surface under zero current conditions after potentiostatic oxidation have been interpreted in terms of a growing copper-rich sulphide layer under anodic polarization. Solid-state diffusion through this layer is suggested as being responsible for the "passivation" process by analogy with the well known de-alloying and back-alloying processes in some binary alloys.

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Section: Introductionmentioning

confidence: 86%

The anodic behaviour of chalcopyrite in chloride solutions: Potentiostatic measurements

Nicol

Zhang

2017

Hydrometallurgy

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“…Chalcocite is the most abundant copper sulfide mineral after chalcopyrite [5,12], and it is the copper sulfide the most easily treated by hydrometallurgical routes [13]. Several investigations have been carried out for the leaching of this mineral with the use of multiple additives and in different media such as; bioleaching [14][15][16][17][18], ferric sulfate solution [19], chloride media [20][21][22][23], pressure leaching for chalcocite [24] and synthetic chalcocite (white metal) [25].…”

Section: Introductionmentioning

confidence: 99%

Leaching of Pure Chalcocite in a Chloride Media Using Sea Water and Waste Water

Toro

Briceño

Pérez

et al. 2019

Metals

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Chalcocite is the most important and abundant secondary copper ore in the world with a rapid dissolution of copper in an acid-chloride environment. In this investigation, the methodology of surface optimization will be applied to evaluate the effect of three independent variables (time, concentration of sulfuric acid and chloride concentration) in the leaching of pure chalcocite to extract the copper with the objective of obtaining a quadratic model that allows us to predict the extraction of copper. The kinetics of copper dissolution in regard to the function of temperature is also analyzed. An ANOVA indicates that the linear variables with the greatest influence are time and the chloride concentration. Also, the concentration of chloride-time exerts a significant synergic effect in the quadratic model. The ANOVA indicates that the quadratic model is representative and the R2 value of 0.92 is valid. The highest copper extraction (67.75%) was obtained at 48 h leaching under conditions of 2 mol/L H2SO4 and 100 g/L chloride. The XRD analysis shows the formation of a stable and non-polluting residue; such as elemental sulfur (S0). This residue was obtained in a leaching time of 4 h at room temperature under conditions of 0.5 mol/L H2SO4 and 50 g/L Cl−.

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“…particularly in the presence of copper ions. (Nicol et al, 2010;Muszer et al, 2013;Zeng et al, 2013). The faster reduction of copper(II) than iron(III) is also apparent in the data for platinum and gold electrodes.…”

Section: Linear Sweep Voltammetric Measurementsmentioning

confidence: 65%

Cathodic reduction of iron(III) and copper(II) on various sulfide minerals in chloride solutions

2016

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A comparative study of the electrochemical reduction of iron(III) and copper(II) ions on selected sulfide minerals in concentrated chloride solutions has been carried out as part of a broader study of the kinetics of the leaching of chalcopyrite, covellite, enargite and pyrite under chloride heap leaching conditions. Mixed potential, cyclic voltammetric and potentiostatic measurements have been made using rotating disk electrodes of massive mineral samples. For comparative purposes, arsenopyrite, platinum and gold electrodes have also been used under the same conditions. The mixed potentials of the various minerals in solutions containing 4.2 mol/L sodium chloride, 0.1 mol/L hydrochloric acid and 0.054 mol/L iron(III) and/or 0.047 mol/L copper(II) ions at 25 o C vary with time depending on the mineral reactivity. The difference between the mixed potentials and the solution potentials provide qualitative indications of mineral reactivity to dissolution with iron(III) or copper(II) as oxidants. Cyclic voltammetry conducted at potentials negative to the mixed potentials at slow sweep rates after the mixed potential measurements has shown variable reactivity of the minerals for reduction of iron(III) and copper(II) ions. The data has been analysed in terms of electrochemical kinetics using a modified Butler-Volmer approach that takes into account mass transport of the oxidized and reduced species and anodic oxidation of the minerals. The electrochemical rate constant derived from a fit of the data to the rate

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Covellinisation of copper sulphide minerals under pressure leaching conditions

Cited by 25 publications

References 9 publications

The anodic behaviour of chalcopyrite in chloride solutions: Potentiostatic measurements

The anodic behaviour of chalcopyrite in chloride solutions: Potentiostatic measurements

Leaching of Pure Chalcocite in a Chloride Media Using Sea Water and Waste Water

Cathodic reduction of iron(III) and copper(II) on various sulfide minerals in chloride solutions

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