Bioleaching of copper with Acidithiobacillus ferrooxidans and role of its extracellular polymeric substances
氧化亚铁硫杆菌浸铜研究及胞外多聚物的作用

In order to obtain the roles of Acidithiobacillus ferrooxidans (ab. A.f.) and extracellular polymeric substances (EPS) in the bioleaching of copper, the experiment with two controls which were both imerged in the same solution with A.f. but one of them with the copper putting into the dialysis bag to stop the direct contact between A.f. and copper was carried out. The experimental results show that: (1) copper has been leached in both of the two processings, and the concentration of copper leached in the solution without and with the dialysis bag are 6 796 mg/L and 1 366 mg/L respectively after leaching for 240 h, so the direct contact between A.f. and copper promoting the bioleaching of copper can be inferred; (2) EPS is important in the bioleaching of copper with A.f. The EPS combined with Fe3+ and mediated the reaction between Fe3+ and copper; (3) the SEM graphs of copper in the two processing show that A.f. adsorption to copper only occurred in the initial stages of the experiment, the rapid leaching of copper in the initial experiment may due to the short mass transfer distance, while the leaching of copper slowing down may due to the increasing mass transfer distance.