Comparison of chalcocite dissolution in the oxygenated, aqueous sulfate and chloride systems

Fisher, W.W.; Flores, Francisco Alfonso; Henderson, J. A. Russell

doi:10.1016/0892-6875(92)90248-8

Cited by 20 publications

(14 citation statements)

References 24 publications

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“…Many publications have confirmed that secondary covellite is formed as an intermediate product during the dissolution of chalcocite (McDonald and Langer, 1983;Rademan et al, 1999;Lawson, 1991a, 1991b;Fisher et al, 1992; A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT Senanayake, 2007;Lee et al, 2008). According to an electrochemical study, this reaction progresses from chalcocite to djurleite, digenite and finally covellite (Arce and González, 2002;Elsherief et al, 1995).…”

Section: Chalcocite Leachingmentioning

confidence: 99%

The kinetics of dissolution of synthetic covellite, chalcocite and digenite in dilute chloride solutions at ambient temperatures

2011

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. (2011) The kinetics of dissolution of synthetic covellite, chalcocite and digenite in dilute chloride solutions at ambient temperatures. Hydrometallurgy, This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPTThe kinetics of dissolution of synthetic covellite, chalcocite and digenite in dilute chloride solutions at ambient temperatures. AbstractAn experimental study of the comparative kinetics of dissolution of various synthetic copper sulphides (covellite, chalcocite, digenite) in dilute chloride solutions has been carried out at ambient temperatures such as could be encountered in the heap leaching of secondary copper sulphide minerals.The dissolution of sized synthetic covellite particles was carried out in dilute HCl solutions containing known concentrations of copper(II) and iron(III) at controlled potentials. The results show that the rate of dissolution is similar at potentials of 600 and 650 mV, but is predictably less at a potential of 550 mV. The rate of dissolution is remarkably similar to that of chalcopyrite under similar conditions and is largely independent of Cl -and HCl concentration in the range 0.2 to 2.5 M and 0.1 to 1 M respectively. The effect of temperature is significant and an activation energy of 71.5 kJ mol -1 was derived which confirms a chemical or electrochemical rate-determining reaction on the mineral surface. A mineralogical study of the residue after leachingshows that most of the sulphur is associated with unreacted covellite and occurs as isolated globules on the surface with over 90% of the unreacted covellite surface free of sulphur.Dissolution of synthetic chalcocite and digenite is rapid compared with that of covellite under the same conditions. At a potential of 500 mV, the relatively rapid A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPTinitial dissolution of chalcocite and digenite does not proceed beyond about 50% and 45% copper dissolution, respectively, as predicted from the thermodynamics. These results confirm the formation of a covellite-like phase as an intermediate which cannot be leached at a potential of 500 mV. An increase in the potential results in rapid dissolution of this "secondary covellite", relative to primary covellite. These results provide useful information for the conditions that should be used for the heap leaching of ores containing secondary copper sulphide minerals.

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Section: Chalcocite Leachingmentioning

confidence: 99%

The kinetics of dissolution of synthetic covellite, chalcocite and digenite in dilute chloride solutions at ambient temperatures

2011

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“…3 Despite some detailed studies, reasons for the beneficial role of low chloride in sulfide leaching in sulfate systems remain unresolved (Cheng and Lawson, 1991a,b;Fisher et al, 1992;Kinnunen and Puhakka, 2004;Brown and Papangelakis, 2005;Carneiro and Leao, 2007). The general view is that during atmospheric leaching in the presence of sodium chloride in sulfuric acid, a porous and somewhat crystalline sulfur layer is formed on the sulfide surface, instead of a tight passivating sulfur layer which blocks the surface Lawson, 1991a, Muir andHo, 2006;Carneiro and Leao, 2007).…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

“…Recent reviews have highlighted the growing interest and conflicting views amongst researchers to understand the mechanistic details of leaching of chalcopyrite and secondary copper minerals in order to promote hydrometallurgical routes to extract copper (Dreisinger, 2006;Watling, 2006;Nicol, 2007;Klauber, 2008;Cordoba et al, 2008a). Chalcocite and covellite are two of the common copper-bearing minerals also formed as intermediate products during the leaching of chalcopyrite, copper matte/residue and copper-nickel sulfides; as shown by some of the reactions relevant to the present study listed in Table 1 (Peters, 1976a,b;Grizo et al, 1982;McDonalds and Langer, 1983;Cheng and Lawson, 1991a,b;Fisher et al, 1992;Grewal et al, 1992;Rademan et al, 1999;Muir and Ho, 2006;Deng et al, 2001;Provis et al, 2003;Nicol and Lazaro, 2003;Ruiz et al, 1998Ruiz et al, , 2007Dreisinger, 2006;Herreros et al, 2006;Vinals, 2007, Cordoba et al, 2008a,b). The dissolution of nickel sulfides via the displacement reactions such as reactions R6-R8 in…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

“…The reaction mechanisms of dissolution/passivation of secondary copper sulfides are relatively simple compared to that of chalcopyrite, but involves a number of interim species. Despite the ionic formula of Cu 2 S 2 reported in the literature, it has been general practice, for simplicity, to use the formula CuS in chemical reactions to represent covellite (Fisher et al,1992;Goh et al, 1996). Koch and McIntyre (1976) (Sullivan, 1933;Mao and Peters, 1983;McDonald and Langer, 1983;Rademan et al, 1999, Cheng andLawson, 1991a,b;Fisher et al, 1992).…”

Section: Interim Copper Compoundsmentioning

confidence: 99%

“…Despite the ionic formula of Cu 2 S 2 reported in the literature, it has been general practice, for simplicity, to use the formula CuS in chemical reactions to represent covellite (Fisher et al,1992;Goh et al, 1996). Koch and McIntyre (1976) (Sullivan, 1933;Mao and Peters, 1983;McDonald and Langer, 1983;Rademan et al, 1999, Cheng andLawson, 1991a,b;Fisher et al, 1992). The nonoxidative acid decomposition of chalcopyrite produces chalcocite and covellite (Peters, 1976a,b), while the chemical metatheses of chalcopyrite in the presence of Cu(II) ions produces covellite and digenite (Sequeira et al, 2008).…”

Section: Interim Copper Compoundsmentioning

confidence: 99%

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A review of chloride assisted copper sulfide leaching by oxygenated sulfuric acid and mechanistic considerations

Senanayake

2009

Hydrometallurgy

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Please cite this article as: Senanayake, G., A review of chloride assisted copper sulfide leaching by oxygenated sulfuric acid and mechanistic considerations, Hydrometallurgy (2009), doi: 10.1016/j.hydromet.2009.02.010 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P T AbstractThe beneficial effect of chloride on sulfide leaching in sulfuric acid has been widely reported over the last 3 to 4 decades but the reasons have not been resolved. A review of recent literature shows that sulfide leaching is complex due to alternative reaction paths, competitive reactions and interim compounds formed on solid surfaces or in solutions. This study focuses on analysis of rate data for covellite leaching by oxygenated sulfuric acid in the presence of sodium chloride and comparison with the leaching data of chalcocite. The published results for initial copper leaching from covellite are analysed on the basis of a shrinking particle kinetic model to determine the apparent rate constants and reaction orders with respect to the concentrations of chloride, dissolved oxygen, and hydrogen ions. The first stage leaching of chalcocite to an intermediate CuS appears to be controlled by the mass transport of oxygen to the sulfide surface. A comparison has been made between the second stage leaching of chalcocite and the initial leaching of pure covellite to produce elemental sulfur by considering the effect of temperature on dissolved oxygen concentration and apparent rate constants. The Arrhenius plots gave comparable values for activation energy for covellite (101 kJ. mol -1 ) and second stage leaching of chalcocite (96 kJ mol -1 ). A linear correlation of stability constants was used to determine equilibrium constants for the formation of CuS 2 and Cu(OH)(Cl). The peak potentials of voltammograms of covellite are in reasonable agreement with the predicted potentials based on thermodynamics of a range of solid phases including CuS, CuS 2 , Cu(OH)Cl, and Cu 2 Cl(OH) 3 . These observations are used to propose a reaction mechanism via mixed-ligand complex species.

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Hydrogen sulfide removal by copper sulfate circulation method

Gao

Weng

Yang

et al. 2016

Korean J. Chem. Eng.

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Comparison of chalcocite dissolution in the oxygenated, aqueous sulfate and chloride systems

Cited by 20 publications

References 24 publications

The kinetics of dissolution of synthetic covellite, chalcocite and digenite in dilute chloride solutions at ambient temperatures

The kinetics of dissolution of synthetic covellite, chalcocite and digenite in dilute chloride solutions at ambient temperatures

A review of chloride assisted copper sulfide leaching by oxygenated sulfuric acid and mechanistic considerations

Hydrogen sulfide removal by copper sulfate circulation method

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