Electrochemical behavior of gold and its associated minerals in alkaline thiourea solutions

He Zhou; Yong-sheng Song; Wen-juan Li; Kun Song

doi:10.1007/s12613-018-1621-8

Volume 25 Issue 7

Jul. 2018

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Article Navigation > International Journal of Minerals, Metallurgy and Materials > 2018 > 25(7): 737-743

He Zhou, Yong-sheng Song, Wen-juan Li, and Kun Song, Electrochemical behavior of gold and its associated minerals in alkaline thiourea solutions, Int. J. Miner. Metall. Mater., 25(2018), No. 7, pp. 737-743. https://doi.org/10.1007/s12613-018-1621-8

Cite this article as:

He Zhou, Yong-sheng Song, Wen-juan Li, and Kun Song, Electrochemical behavior of gold and its associated minerals in alkaline thiourea solutions, Int. J. Miner. Metall. Mater., 25(2018), No. 7, pp. 737-743. https://doi.org/10.1007/s12613-018-1621-8

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Research Article

Electrochemical behavior of gold and its associated minerals in alkaline thiourea solutions

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Corresponding author:
Wen-juan Li E-mail: juanzi88888@126.com
Received: 10 October 2017; Revised: 23 January 2018; Accepted: 30 January 2018

Abstract

Abstract

Electrochemical measurements were conducted to study the electrochemical behavior of gold (Au) and its commonly associated minerals in alkaline thiourea solutions. The results indicated that without addition of any stabilizer, selective dissolution of Au from stibnite and pyrite was only possible at relatively low thiourea concentrations. As Na₂SiO₃ was added, pyrite started to become active and an oxidation peak appeared; the oxidation peaks of arsenopyrite and chalcocite appeared earlier than that of Au. The chalcocite peak shifted in the positive direction and the peak current increased. Stibnite did not show an oxidation peak and its current was nearly zero. Adding Na₂SiO₃ favored the selective dissolution of Au when its minerals were associated with chalcocite and stibnite. At pH 12, the Au anode dissolution peak current increased with stabilizer concentration. At 0.38 and 0.42 V and for Na₂SiO₃ concentration below 0.09 M, the current density continuously increased with Na₂SiO₃ concentration. The Na₂SiO₃ concentration had to be adequate to stabilize thiourea. When the potential was higher than 0.42 V, the surface of the Au electrode started to passivate. With an additional increase in potential, the presence of Na₂SiO₃ could not stop the inevitable decomposition of thiourea.
- alkaline thiourea;
- Au;
- associated mineral;
- Na₂SiO₃;
- electrochemical behavior

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