Abstract:

Compared with other pretreatment methods of arsenic-bearing refractory gold ore，biooxidation has some advantages such as low capital cost and easily operating，which are appropriate for small and medium sized gold mines.But the relatively low aeration efficiency in the biooxidation lead to require lots of aeration and high power cost.In this study，a novel structure of the stirred reactor is proposed，which improves the aeration efficiency and the way of agitation，can reduce amount of aeration and cost of power consumption by increasing the efficiency of biooxidation.Acidithiobacillus ferrooxidans（At.f） is applied to leach the arsenic-bearing refractory floatation gold concentrate in a 100 L stirred tank reactor with and without draft tube.The pH and redox potential（Eh），are monitored and sampled regularly for measurement of total amount of iron and total amount of arsenic.The treated concentrate is analyzed with XRD and SEM.The results show that in the biooxidation process of two weeks，at the second day of biooxidation Eh increases rapidly and the maximum value is 497 mV，the arsenic removal rate reaches 34.86%，and gold extraction rate reaches 58%.

Key words: biooxidation, refractory gold ore, stirred tank, draft tube