Journal article
The electrochemical behaviour of enargite in ammoniacal solutions. II. Cathodic reactions
Hydrometallurgy, Vol.189, Article 105115
2019
Abstract
A detailed electrochemical study has been made of the cathodic reduction of copper(II) ions and dissolved oxygen on an enargite electrode in ammoniacal sulfate and chloride solutions under ambient conditions. The rate of the reduction of copper(II) to copper(I) on an enargite surface in ammoniacal sulfate solutions is rapid and can be described in terms of a quasi-reversible system. The rate is first-order in the concentration of copper(II) ions and is sensitive to mass transport even at low overpotentials. The kinetics and mechanism in chloride solutions are quantitatively similar to those in sulfate solutions. The rate of reduction decreases with increasing ammonia and ammonium ion concentrations and a model has been developed in which the rate is approximately proportional to the concentration of the tri-ammine copper(II) species, the concentration of which decreases as the concentrations of ammonia and ammonium ions increases.
The rate of reduction of dissolved oxygen is very much slower than that of copper(II) and occurs in two steps with peroxide as the intermediate species. The dissolution of enargite in oxygenated ammoniacal solutions containing copper(II) ions occurs as a typical redox-mediated mechanism in which oxygen re-oxidises copper(I) produced by reduction of copper(II) on the enargite surface i.e. copper(II) is the effective oxidant.
Details
- Title
- The electrochemical behaviour of enargite in ammoniacal solutions. II. Cathodic reactions
- Authors/Creators
- M.J. Nicol (Author/Creator) - Murdoch UniversityA. Ruiz-Sánchez (Author/Creator) - Universidad Autónoma MetropolitanaG. Senanayake (Author/Creator) - Murdoch UniversityV. Tjandrawan (Author/Creator) - Murdoch UniversityG.T. Lapidus (Author/Creator) - Universidad Autónoma Metropolitana
- Publication Details
- Hydrometallurgy, Vol.189, Article 105115
- Publisher
- Elsevier BV
- Identifiers
- 991005541535507891
- Copyright
- © 2019 Elsevier B.V.
- Murdoch Affiliation
- College of Science, Health, Engineering and Education
- Language
- English
- Resource Type
- Journal article
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- 7.229 Mineral & Metal Processing
- 7.229.774 Bioleaching
- Web Of Science research areas
- Metallurgy & Metallurgical Engineering
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- Materials Science