采用中温菌和常温菌浸出含砷金精矿

Bioleaching arsenic-containing gold concentrates with MLY and At.f

考察了不同矿浆浓度和接种量对细菌浸出含砷金精矿的影响。结果表明:中度嗜热嗜酸铁氧化菌MLY和嗜酸氧化亚铁硫杆菌(Acidthiobacillus ferrooxidans,At.f)的浸矿效果不同。MLY和At.f对含砷金精矿的浸出机理也不同;接种MLY的矿浆中,可能主要是溶液中的细菌将Fe2+氧化为Fe3+,再由Fe3+氧化溶解矿物,即以间接浸出作用为主;而接种At.f可能首先是At.f被吸附到矿物表面,通过细菌与矿物之间的某种界面作用引起矿物溶解,矿物溶解产生的Fe2+被游离菌氧化成为Fe3+,从而溶解矿物,即At.f浸出可能包括直接作用和间接作用的共同效应。

To comprehend the bioleaching mechanisms of arsenic-containing gold concentrates with moderately thermoacidphilic iron-oxidizing bacterium MLY and Acidthiobacillus ferrooxidans（At.f）, bioleaching experiments were carried out, in which different pulp densities and inoculations were performed. It is found that MLY and Atf show different behaviors in the bioleaching process and these results suggest that MLY and At.f have different bioleaching mechanisms. In the MLY leaching, Fe^2＋ is oxidized to generate Fe^3＋ by the free bacteria in solution, and then arsenopyrite is dissolved by Fe^3＋, that is to say, the indirect action is much more significant in MLY leaching. On the other hand, in the At.f leaching, the bacteria is attached to the mineral surface firstly, then the mineral is dissolved and Fe^2＋ is released into the solution. Fe^2＋ in the solution is oxidized to produce Fe^3＋ by free bacteria, and then Fe^3＋can attack the mineral as well. So the united mechanisms contain direct action and indirect action in the At.f leaching.