Electrodissolution of synthetic covellite in hydrochloric acid

Ghali, Edward; Dandapani, B.; Lewenstam, Andrzej

doi:10.1007/bf00615104

Cited by 23 publications

(9 citation statements)

References 9 publications

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“…Cheng and Lawson (1991a) showed that the rate of covellite dissolution increased with increasing sulphuric acid concentration up to 0.02 M above which concentration the effect became negligible. In contrast, Ghali and Dandapani (1982) reported that a high concentration of HCl accelerated the anodic dissolution of covellite because of the formation of a CuCl 2 -complex ion.…”

Section: Effect Of Acid Concentrationmentioning

confidence: 92%

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: Effect Of Acid Concentrationmentioning

confidence: 92%

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

2011

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“…It is well known (MacKinnon, 1976;Ghali et al, 1982;Hillrichs and Bertram, 1983;Lee et al, 2008) that the anodic dissolution of covellite is, like chalcopyrite, subject to passivation/retardation in both sulfate and chloride solutions. A comparison of the anodic behaviour of the two minerals therefore could reveal some important similarities that could assist in considerations of the mechanism(s) involved in the passivation process.…”

Section: Comparison With Covellitementioning

confidence: 99%

The anodic behaviour of chalcopyrite in chloride solutions: Voltammetry

2017

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This paper summarizes the results of a voltammetric study of the anodic characteristics of chalcopyrite in the potential region relevant to heap leaching in concentrated chloride solutions. Distinct peaks in the potential region of 0.7 to 0.85 V have been observed in the voltammograms, the magnitude of which depend on the chloride concentration and, particularly, the pH in the range 1 to 3. Three peaks are observed at low chloride concentrations that merge into one peak at higher concentrations. The anodic reactivity increases with increasing pH but shows a complex dependence on the chloride concentration while in the presence of added copper(II) ions, the mixed potential shifts to more positive potentials and only one peak is observed. Hysteresis between the forward and backward-going sweeps has confirmed the transient nature of the processes except at potentials below about 0.75 V in which region the system approaches steady-state behaviour. The voltammetric characteristics of chalcopyrite in this system appear to be very similar to those of covellite. Measurements of the initial rates of dissolution (in the range 1-5 x 10-10 mol cm-2 s-1 depending on the conditions) have been made that confirm the voltammetric trends and compare well with previously published rates.

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“…), several alternative processes using mechanochemical, electrochemical and sonochemical treatments have been tested and reported, but they were focused mainly on primary sulfide minerals such as chalcopyrite and chalcocite. In particular, the mechanochemical process has advantages over the others, including no need for additional equipment and procedural simplicity, despite this method had some drawbacks such as agglomeration of fine particles and the relatively lower energy efficiency in the prolonged grinding [17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Effect of Mechanical Activation on the Kinetics of Copper Leaching from Copper Sulfide (CuS)

Lee

Kim

et al. 2018

Metals

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Abstract:The effect of mechanical activation on the copper leaching of copper sulfide, CuS, in 1 M HNO 3 (slurry density: 10 g/L) was investigated by analysis of the leachability and the apparent activation energy. Mechanical activation produced an increase in the leachability and a decrease of the activation energy in this leaching reaction. The leachability increased proportionally to the degree of mechanical activation, reaching 96.6% leaching within 60 min at 80 • C from CuS ground at 700 rpm for 15 min. This leaching process was controlled by surface chemical reaction following the shrinking-core model. The apparent activation energy of leaching for CuS (71.5 kJ/mol) in the range of 50 to 80 • C decreased with an increase of the degree of mechanical activation, reaching 44.3 kJ/mol for Cu leaching from CuS ground at 700 rpm for 15 min.

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Electrodissolution of synthetic covellite in hydrochloric acid

Cited by 23 publications

References 9 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

The anodic behaviour of chalcopyrite in chloride solutions: Voltammetry

Effect of Mechanical Activation on the Kinetics of Copper Leaching from Copper Sulfide (CuS)

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