Co-intensification Of Bio-oxidation Of As-bearing Gold Ores

Abstract:Biological pre-oxidation of As-bearing gold ores has got more and more attention due to its high gold recovery and low cost, however its further development has been restricted with the problems of long period and low oxidation rate. Based on present research, the study carried out Co-intensification with the addition of oxidants(ammonium persulfate,Fe (III)) and metal ions (Ag(I), Cu(II)).The research of biological pre-oxidation of As-bearing gold ores showed that the main problems of biological pre-oxidation leaching19.32%As-bearing gold ores without any additives are long period and low oxidation rate; the leaching rate of arsenic was just7.48%after22days.oxidants and metal ion additives alone can strengthen the arsenic leaching rate, but the effect is still not significant; when co-intensification of oxidants and metal ions was carried out, arsenic leaching rate increased significantly. The oxidation rate represents64.55%with the co-intensification of Ag (Ⅰ)-Fe (Ⅲ) after17days, increasing49.66% than with catalysts alone and representing an increase of39.55% than with oxidants alone. When the co-intensification of Ag (Ⅰ) and Fe(Ⅲ) Oxidation is carried out to gold ores with8.73%arsenic, the leaching rate has already increased to60%after6days and81%after13days.Electrochemical studies showed that:ammonium persulfate and iron ions make cathodic reaction rate greatly improved; Cu(Ⅱ) and Ag(Ⅰ) both accelerated anodic dissolution of arsenopyrite and more conductive to oxidation of As (Ⅲ), Fe (Ⅱ), S0, the effect was most significant with the bacteria. However, Cu(Ⅱ) was easier to produce passivation, compared to Ag(Ⅰ).The results provide theoretical and technical guidance for strengthening biological pre-oxidation of As-bearing gold ores.There are50figures,7tables,111references.