Bioxidative dissolution of cinnabar by iron-oxidizing bacteria

In the present study, bioleaching characteristic of cinnabar and process parameters were investigated. The effects of temperature, initial pH of the solution, dilution rate and iron on the cinnabar bioleaching were examined. The relationship between the redox potential and extraction of mercury was evaluated. Based on the S/N ratio, the optimized conditions for bioleaching were established. Iron of the solution was the most effective parameter in comparison with others. A maximum mercury concentration of 1.38 g/L was achieved. The indirect mechanism plays a major role in bioleaching. Some jarosite crystal deposits could be found when the iron concentration was 4.0 g/L and initial pH was 1.9. The bioxidation of sulfur could inhibit the hydrolyzation of ferric iron. Regulating pH value and ion concentration in medium could control the formation of the precipitation. (C) 2013 Elsevier B.V. All rights reserved.