Effects of processing pH stimulation on cooperative bioleaching of chalcopyrite concentrate by free and attached cells
(1. School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Biometallurgy, Ministry of Education, Central South University, Changsha 410083, China;
3. CSIRO Process Science and Engineering, Box 312, Clayton South, Victoria 3169, Australia)
2. Key Laboratory of Biometallurgy, Ministry of Education, Central South University, Changsha 410083, China;
3. CSIRO Process Science and Engineering, Box 312, Clayton South, Victoria 3169, Australia)
Abstract: In order to investigate the effects of processing pH stimulation on bioleaching of chalcopyrite by moderate thermophiles, copper leaching rates and the dynamics of microbial community structures of free and attached cells were monitored. The results indicated that when the processing pH values were respectively adjusted to 1.0 and 3.0 on day 14, both free and attached cells experienced an adaptive phase. Meanwhile, the copper leaching rates were 86.9% and 64.0%，respectively, as opposed to a copper leaching rate of 87.5% in the control group without pH stimulation. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis suggested that pH stimulation imposed less impact on the attached organisms than on the free cells, indicating that the attached cells were more resistant to processing pH stimulation than the free cells. Furthermore, adjusting processing pH to 3.0 significantly disrupted both free and attached microbial communities, and the bioleaching system could not recover to the normal status as the control group.
Key words: chalcopyrite; processing pH stimulation; free cells; attached cells; microbial community; real-time quantitative PCR