铁闪锌矿细菌浸出过程中亚铁和细菌初始浓度的影响

利用摇瓶浸出研究了氧化亚铁硫杆菌在35℃下生物浸出铁闪锌矿的过程，探讨了铁含量和细菌接种量等因素对细菌在矿浆中的生长以及对锌浸出的影响，并对细菌浸出铁闪锌矿的机理进行了分析. 发现在不添加铁的情况下，即使细菌接种量达到40 mL，矿浆的氧化还原电位提高仍然非常缓慢，细菌无法在矿浆中正常生长，证明不存在直接浸出；而在添加FeSO4×7H2O的矿浆中，随接种量的增加细菌浸出铁闪锌矿的速度加快. 结果表明，铁闪锌矿的浸出需要一定量的Fe3+作为氧化浸出剂以提高浸出速度，因此必须预先添加部分Fe2+作为细菌氧化生成Fe3+的来源. 通过分析浸出过程中矿浆Eh和铁浓度的变化，认为Eh的高低与细菌浸出速度直接相关. 并且根据实验和电镜分析证明氧化亚铁浸出铁闪锌矿的过程是pH值上升的耗酸过程.

Effects of External Addition of Fe2+ and Inoculum on Bioleaching of Marmatite Flotation Concentrate

Bioleaching of marmatite flotation concentrate by Acidithiobacillus ferrooxidans was carried out in a swing bed under 35℃. The effects of external addition of Fe2+ and the inoculum of the bacteria were studied, and a dissolved mechanism of the marmatite was proposed. The results showed that the improvement of Eh was very slow in the slurry absent of Fe2+, even though 40 mL inoculum was used. This suggests that the bacteria can hardly bioleach the mineral if there are not enough ferric ions in the slurry. With the addition of FeSO4×7H2O, the improvement of Eh was obvious and the leaching rate was enhanced with the improvement of the inoculum. These results indicated that the supplementary addition of ferrous iron as a source of ferric ion to be generated by the bacteria was necessary in the bioleaching of marmatite. The evolution of Eh and the concentration of total iron in the bioleaching indicated that Eh was more important than the concentration of Fe3+ in the dissolution of marmatite. On the other hand, it was found that the bioleaching of marmatite was a process with consumption of H+, as a result, the pH value of leaching solution increased continually.