方解石对铁闪锌矿生物浸出行为的影响及机理探讨

考察了在30 ℃、pH=2、细菌浓度2×107 个/mL条件下方解石粒径与质量浓度对铁闪锌矿生物浸出的影响。结果表明，随着方解石粒径增加，体系pH值随之升高，嗜酸氧化亚铁硫杆菌增长缓慢，抑制Fe、Zn浸出；随着方解石质量浓度增加，体系中Ca²⁺浓度随之增加，对Fe、Zn浸出率的影响表现为先促进后抑制，当Ca²⁺浓度为130.27 mg/L时，能够促进嗜酸氧化亚铁硫杆菌增长，促进浸出；Ca²⁺浓度继续升高则不利于细菌增长与离子浸出；方解石粒径为-0.038 mm且质量浓度为10 g/L时浸出30 d，浸出效果较好，Fe和Zn浸出率分别达到80.53%和95.99%。

Effect of Calcite on Bioleaching of Marmatite and Discussion of Its Mechanism

The effects of particle size and mass concentration of calcite on the bioleaching of marmatite at 30 ℃,with pH of 2 and bacterial concentration of 2×107 cell/mL were investigated. The results show that as the particle size of calcite increases, the pH of the solution in the system increases and Acidithiobacillus ferrooxidans (A f) grows slowly, which inhibits the leaching of Fe and Zn. As the mass concentration of calcite increases, the concentration of Ca²⁺ in the system also increases, but the leaching of Fe and Zn will be initially promoted and then inhibited. The growth of A f bacteria can be promoted with the Ca²⁺ concentration of 130.27 mg/L, which can also improve the leaching effect. However, a continuous increase of Ca²⁺ concentration is not conducive to the growth of bacteria and ion leaching. It is found that a better leaching effect can be obtained with the particle size of calcite less than 0.038 mm and the mass concentration of 10 g/L. Under such conditions, the leaching rates of Fe and Zn reach 80.53% and 95.99%, respectively.