关键词: 生物浸出, 氧化亚铁硫杆菌, 铁闪锌矿, 氧化还原电位, 接种量

Abstract: 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.

Key words: bioleachin, Acidithiobacillus ferrooxidans, marmatite, Eh, inoculum