材料期刊网

采用含铁氧化菌和硫氧化菌的混合嗜中温菌群浸出阿根廷Andacollo矿的含金硫化浮选精矿.实验在摇瓶中进行,矿浆浓度为10%,采用pH 1.8的含亚铁离子的基础盐溶液作为介质.采用不同的方法对浸出液的pH值、氧化还原电位、亚铁离子和总金属浓度进行测定.结果表明,该种混合菌能够很好地还原浸出该难处理金矿,金的回收率可达91.6%,同时,铜和锌的浸出率也较高.动力学研究表明金属的溶解符合收缩核模型.其中,铜的溶解速率受生成产物层的扩散控制,而锌的溶解没有明显的控制步骤.

A defined mesophilic consortium including an iron oxidizing bacterium and a sulfur oxidizing bacterium was constructed to evaluate its ability for bioleaching a flotation concentrate from Andacollo mine in Neuquén, Argentina. Experiments were performed in shake flasks with a pulp density of 10% (w/v), using a basal salt medium containing ferrous iron at pH 1.8. The leaching solutions were analyzed for pH, redox potential (using specifics electrodes), ferrous iron (by UV-Vis spectrophotometry) and metal concentrations (by atomic absorption spectroscopy). The results showed that the consortium was able to reduce the refractory behavior of the concentrate, allowing 91.6% of gold recovery; at the same time, high dissolution of copper and zinc was reached. These dissolutions followed a shrinking core kinetic model. According to this model, the copper solubilization was controlled by diffusion through a product layer (mainly jarosite), while zinc dissolution did not show a defined control step. This designed consortium, composed of bacterial strains with specific physiological abilities, could be useful not only to optimize gold recovery but also to decrease the leachates metallic charge, which would be an environmental advantage.