Surface electron transfer promoted by Peroxymonosulfate oxidant enhances bioleaching of arsenic-containing gold ore

Abstract

Improving the efficiency of leaching arsenic from arsenic-containing gold ores is still a problem that needs to be solved urgently by traditional biological oxidation method. In this work, the effect of oxidant on mineral leaching and the change of arsenic ion valence during biological oxidation were investigated in detail. The results showed that when 5 g/L Peroxymonosulfate(PMS) was added on the second day of bioleaching, the concentration of arsenic ion in the solution was 0.682 g/L on the 14th day of the reaction, and the leaching rate of arsenic reached 71.06 %. Compared with the mixed microbial leaching system, the leaching rate of arsenic was increased by 8.95 %, while the content of As (Ⅲ) was decreased by 12.82 %. The results of electrochemical experiments show that PMS plays a cathode strengthening role in mineral oxidation and the passivation phenomenon in the process of microbial leaching is reduced by improving the oxidation capacity of the system. And the dissolved charge transfer resistance of the mineral is reduced from 44.17 Ω to 32.29 Ω. This study provides a new research perspective for improving the arsenic leaching rate of arsenic-containing gold ores, and our strategy also provides guidance for the research mechanism of increasing the arsenic leaching rate.