title: Two-Step Oxidation of Refractory Gold Concentrates with Different Microbial Communities.
abstract: Bio-oxidation is an effective technology for treatment of refractory gold concentrates. However, the unsatisfactory oxidation rate and long residence time, which cause a lower cyanide leaching rate and gold recovery, are key factors that restrict the application of traditional bio-oxidation technology. In this study, the oxidation rate of refractory gold concentrates and the adaption of microorganisms were analyzed to evaluate a newly developed two-step pretreatment process, which includes a high temperature chemical oxidation step and a subsequent bio-oxidation step. The oxidation rate and recovery rate of gold were improved significantly after the two-step process. The results showed that the highest oxidation rate of sulfide sulfur could reach to 99.01 % with an extreme thermophile microbial community when the pulp density was 5%. Accordingly, the recovery rate of gold was elevated to 92.51%. Meanwhile, the results revealed that moderate thermophiles performed better than acidophilic mesophiles and extreme thermophiles, whose oxidation rates declined drastically when the pulp density was increased to 10% and 15%. The oxidation rates of sulfide sulfur with moderate thermophiles were 93.94% and 65.73% when the pulp density was increased to 10% and 15%, respectively. All these results indicated that the two-step pretreatment increased the oxidation rate of refractory gold concentrates and is a potential technology to pretreat the refractory sample. Meanwhile, owing to the sensitivity of the microbial community under different pulp density levels, the optimization of microbial community in bio-oxidation is necessary in industry.
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, Hunan, P.R. China.|Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha 410083, Hunan, P.R. China.
authors.forename: Guo-Hua
authors.initials: GH
authors.lastname: Wang
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, Hunan, P.R. China.|Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha 410083, Hunan, P.R. China.
authors.forename: Jian-Ping
authors.initials: JP
authors.lastname: Xie
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, Hunan, P.R. China.|Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha 410083, Hunan, P.R. China.
authors.forename: Shou-Peng
authors.initials: SP
authors.lastname: Li
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, Hunan, P.R. China.|Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha 410083, Hunan, P.R. China.
authors.forename: Yu-Jie
authors.initials: YJ
authors.lastname: Guo
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, Hunan, P.R. China.|Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha 410083, Hunan, P.R. China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Pan
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, Hunan, P.R. China.|Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha 410083, Hunan, P.R. China.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Wu
authors.affiliation: School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, Hunan, P.R. China.|Key Laboratory of Biohydrometallurgy of Ministry of Education, Central South University, Changsha 410083, Hunan, P.R. China.
authors.forename: Xin-Xing
authors.initials: XX
authors.lastname: Liu
mesh_terms: D001419:Bacteria / Q000737:chemistry / Q000378:metabolism*; D001673:Biodegradation, Environmental; D006046:Gold / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D010084:Oxidation-Reduction; D013440:Sulfides / Q000737:chemistry / Q000378:metabolism; D013455:Sulfur / Q000737:chemistry / Q000378:metabolism
chemical_list: D013440:Sulfides; D013455:Sulfur; D006046:Gold
keywords: Bio-oxidation; extreme thermophiles; mesophiles; moderate thermophiles; two-step process