Bioleaching of Sphalerite by the Native Mesophilic Iron-oxidizing Bacteria from a Lead-Zinc Tailing

An isolated native mesophilic iron-oxidizing bacteria, acidithiobacillus ferrooxidans, was used to extract zinc by the bioleaching method from a typical lead-zinc tailing. Experiments were carried out by mixed culture of the mesophilic strain in the shake flasks and the different influencing factors such as pH, temperature, inoculation cell number, as well as slurry concentration on the process of bioleaching were investigated. The results indicated that the extraction efficiency of zinc was relevant with these variables and more than 70% of sphalerite was dissolved on the condition of with pH 2.0, initial ferrous concentration of 10 g/L and slurry concentration of 10 wt.% during 25 d, while without bacteria, 22% of Zn was merely extracted.