The galvanic interaction between gold and pyrite in the presence of ferric ions. (April 2018)

• Record Type: Journal Article
• Authors: Huai, Yangyang; Plackowski, Chris; Peng, Yongjun
• Is Part Of: Minerals engineering. Volume 119(2018)
• Page Start: 236
• Page End: 243
• Publication Date: 2018-04
• Subjects: Pyrite -- Gold -- Galvanic interactions -- Ferric ions -- Oxidation -- Dissolution; Mines and mineral resources -- Periodicals; Ressources minérales -- Périodiques; Mines and mineral resources; Periodicals; Electronic journals; 622
• DOI: 10.1016/j.mineng.2018.01.040
• Languages: English
• ISSNs: 0892-6875

Abstract

Graphical abstract: Highlights: Gold was more active than pyrite at pH 2 in the absence of Fe 3+ . Gold became much nobler than pyrite in the presence of Fe 3+ . Fe 3+ slightly increased the oxidation of pyrite without coupling with gold. Fe 3+ significantly increased the oxidation of pyrite coupled with gold. Fe 3+ also significantly increased the dissolution of pyrite coupled with gold. Abstract: The current study investigated the galvanic interaction between gold and pyrite in the presence of Fe 3+ to identify a means of facilitating the exposure of gold from its carrier mineral pyrite. It was found that gold was nobler than pyrite in the presence of ferric ions and a static current was generated once gold and pyrite were coupled. Dynamic polarization studies indicated that gold could catalyse the reduction of Fe 3+, and Fe 3+ provided a more oxidizing effect on pyrite coupled with gold than that on pyrite without the coupling. This resulted in a significant increase in the oxidation rate of pyrite coupled with gold. Electrochemical characterization of pyrite surface and aqueous solution was also conducted after pyrite was oxidised with and without coupling with gold. A more extensive sulphur-rich layer was formed on pyrite after coupled with gold. The solution from galvanic oxidation also contained a much higher amount of oxidation products dissolved from pyrite surface. This study suggests that Fe 3+ can enhance the oxidation and dissolution of pyrite coupled with gold.