Evaluation of Bioleaching Factors on Gold Recovery from Low-grade Ore by Cyanide-producing Bacteria

摘要

The present study was conducted to investigate the feasibility of gold bioleaching by Chromobacterium violaceum from gold containing low grade ores. The optimal condition for cyanide production by C. violaceum in batch culture was pH 9 and 5 g/L of glycine. In shake flask culture, gold bioleaching was enhanced by pre-incubation, grinding of the ores less than 180 μm, pH adjustment from 9 to 11, and biooxidative treatment to liberate gold particle. The bioleaching by C. violaceum with pre-incubation and grinding dissolved almost all of cyanidable gold in the ores. Biooxidation as a pretreatment and pH adjustment did not affect the bioleaching efficiency. These results indicated that bioleaching by C. violaceum in optimal experimental condition can be used as an alternative of chemical cyanidation. The potential use of C. violaceum in gold bioleaching is of significance in terms of environmental friendly and cost-saving leaching method.