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A fundamental study of gold leaching in a thiosulfate‑oxygen‑copper system in the presence of activated carbon

Sitando, O., Dai, X., Senanayake, G., Nikoloski, A.N. and Breuer, P. (2020) A fundamental study of gold leaching in a thiosulfate‑oxygen‑copper system in the presence of activated carbon. Hydrometallurgy, 192 . Art. 105232.

Link to Published Version: https://doi.org/10.1016/j.hydromet.2019.105232
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Abstract

Activated carbon has been found to significantly enhance the dissolution of gold in a thiosulfate‑oxygen‑copper system. Leaching tests using gold powder showed that the gold dissolution in a thiosulfate‑oxygen‑copper system in the absence of activated carbon was very slow, with only 2% gold dissolved over 24 h. In contrast, in the presence of activated carbon as an additive the gold leach recovery was dramatically improved to over 95% in the same period. Leaching and electrochemical studies using a gold rotating disc electrode have identified two impacts of activated carbon on the dissolution of gold: 1) enhancing the oxygen reduction half reaction via galvanic interaction and; 2) enhancing the gold oxidation half reaction via removal of the surface passivation. A combination of the two effects can potentially increase the gold leach rate to the same order of magnitude as a typical cyanidation rate (10−5 mol m−2 s−1). It has also been found that the presence of copper and the use of an elevated temperature are beneficial for the gold leaching; whilst the use of oxygen instead of air and change in pH between pH 7 and pH 10 have little impact.

Item Type: Journal Article
Murdoch Affiliation: College of Science, Health, Engineering and Education
Publisher: Elsevier BV
Copyright: © 2019 Elsevier B.V.
URI: http://researchrepository.murdoch.edu.au/id/eprint/54850
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