Application of the BIOX process to the pretreatment of refractory sulphide gold ores and concentrates in order to increase Au and Ag recovery rate in hydrometallurgical extraction process [articol]

Abstract

The key of the BIOX process is the exploitation of a naturally occurring mixed bacterial population consisting of: Acidithiobacillus ferooxidans, Acidithiobacillus thiooxidans (oxidises sulphur compounds only) and Leptospirillum ferooxidans (oxidizes iron substrates only). These bacteria are able to oxidize gold-bearing sulphide ores and concentrates under controlled conditions. Thus, they offer an alternative to conventional roasting or pressure techniques developed in hydrometallurgy in order to recovery Au and Ag from refractory sulphide gold ores and concentrates. Using the BIOX process as a pretreatment procedure of refractory sulphide gold ores and concentrates, Au and Ag recovery yields after cyanidation increased up to 78 % for Au and to 83 % for Ag.