Pre-oxidation of refractory gold concentrate by electrochemical methods in alkaline electrolyte. (June 2022)

• Record Type: Journal Article
• Authors: Xu, Guixiao; Deng, Fanlei; Fan, Wenwen; Shi, Zhuonan; Ma, Ruixin; Wang, Chengyan
• Is Part Of: Materials today communications. Volume 31(2022)
• Publication Date: 2022-06
• Subjects: Refractory gold concentrate -- Pretreatment method -- Electrochemical oxidation -- Electrochemical technique -- Ion beam etching; Materials science -- Periodicals; 620.11
• DOI: 10.1016/j.mtcomm.2022.103397
• Languages: English
• ISSNs: 2352-4928

Abstract

Abstract: Pretreatment has been the focus of refractory gold concentrate, and many methods were developed. Pre-oxidation by electrochemical methods is environmentally friendly. The reaction mechanism of electrochemical oxidation of gold ore in an alkaline electrolyte at pH 10 was studied in this paper. The results suggest that the refractory gold concentrate electrochemical oxidation was divided into two different stages according to different oxidation products. The first one is passive-film-forming stage below 0.7 V (vs. SCE), when products are ferric hydroxide and high-sulfur products, including elemental sulfur or polysulfides, which form a passive film that hinders the further oxidation. Another is conventional continuous-oxidation mechanism, and products are soluble sulfate when the potential is maintained higher potentials. By the aid of ion beam etching (IBE), SEM and linear EDS scanning, a clear sulfur-rich outer ring structure morphology image caused by the electrochemical oxidation has been obtained in electrode surface. For pyrite-encapsulated gold deposits, it is important to provide a potential higher than 0.7 V (vs. SCE) for gold enrichment, when electrochemical pre-oxidation is employed. Graphical Abstract: ga1