微生物-矿物接触作用对金属硫化物溶解的影响——氧化亚铁硫杆菌参与黄铜矿溶解的初步研究

在表生条件下,氧化亚铁硫杆菌的参与能够有效促进黄铜矿的氧化分解,前人研究认为微生物对黄铜矿的溶解有直接和间接作用,但相对贡献仍存在争议。利用透析膜将细菌和黄铜矿隔离,模拟对比了黄铜矿与氧化亚铁硫杆菌不接触和直接接触时的溶解行为。利用等离子光谱(ICP-AES)测定两种实验条件下溶液中Cu2+离子的浓度变化,并利用扫描电子显微镜(SEM)观察了两种条件下黄铜矿表面特征的变化和次生产物特征。实验发现在两种模式下,氧化亚铁硫杆菌均不同程度提高了黄铜矿的溶解速率;直接接触模式比非接触模式对黄铜矿氧化分解的促进作用更显著。

Effects of microbe-mineral contacting on the dissolution of metal sulfids: a prelimi-nary study on chalcopyrite dissolution mediated by Acidothiobacillus ferrooxidans

In the hypergenesis processes,the presence of Acidothiobacillus ferrooxidans can effectively promote the dissolution of chalcopyrite.Previous studies indicate that the dissolution mechanisms of chalcopyrite include direct and indirect mechanism.However,the contribution of each mechanism to the mineral dissolution is still in controversy.By the employment of microfiltration membrane to segregate minerals from bacteria,this study simulated and compared the dissolution behaviors of chalcopyrite in the conditions of indirect and direct contact with Acidothiobacillus ferrooxidans.The variations of Cu2+ concentrations of the solution of both experiments were analyzed by using inductively coupled plasma-atomic emission spectrometry(ICP-AES),and the surface morphology of chalcopyrite and secondary precipitation were observed by using scanning electron microscope(SEM).This study indicates that Acidothiobacillus ferrooxidans can clearly promote the dissolution of chalcopyrite through either mechanisms,and that the effect of direct mechanism on the dissolution is more efficient than that of indirect one.