Bioleaching and electrochemical property of marmatite by Sulfobacillus thermosulfidooxidans

铁闪锌矿的Sulfobacillus thermosulfidooxidans菌浸出及电化学性能（英文）

Bioleaching and electrochemical experiments were conducted to evaluate marmatite dissolution in the presence of pure S.thermosulfidooxidans.The effects of particle size,p H controlling and external addition of Fe^3＋ ions on the zinc extraction were investigated.The results show that in the bioleaching process the best particle size range is 0.043-0.074 mm and adjusting p H regularly to the initial value has a profound effect on obtaining high leaching rate.External addition of Fe^3＋ ions could accelerate the bioleaching,while the concentration of additional Fe^3＋ over 2.5 g/L weakens the positive effect,and even hinders the dissolution of marmatite.SEM and XRD analyses of the leaching residues reveal that a product layer composed of elemental sulfur and jarosite is formed on the mineral surface,which results in a low leaching speed at later phase.The results of electrochemical measurements illustrate that additional Fe^3＋ ions could increase the corrosion current density,which is favorable to zinc extraction.The EIS spectra show that rate-limiting step does not change when Fe^3＋ ions are added.

采用纯种Sulfobacillus thermosulfidooxidans菌进行铁闪锌矿的生物浸出及电化学实验,研究颗粒大小、p H值控制和外加Fe^3＋离子对锌浸出的影响。结果表明：在生物浸出过程中铁闪锌矿生物浸出的最佳粒度范围为0.043~0.074 mm;定期调整p H值至初始值对获得较高的浸出率有重要影响;外加Fe^3＋离子能加速铁闪锌矿的生物浸出,但当外加Fe^3＋离子浓度超过2.5 g/L时,促进作用变弱,甚至阻碍铁闪锌矿的溶解。SEM和XRD分析浸渣发现,在矿物表面形成一层由单质硫和黄钾铁矾组成的产物层,并导致后期的浸出速度低。电化学测试实验结果表明,外加Fe^3＋离子可以增加腐蚀电流密度,有利于锌的提取。交流阻抗谱表明,添加Fe^3＋离子后没有改变反应过程的控制步骤。