Investigation of the bioleaching of coarse sphalerite ore particles by a mixed culture of mesophilic chemolithotrophs in saturated leach reactors
Although the bioleaching of sulphide ores is well studied, the relatively coarse particle size, typical of heap and dump leach operations, presents unique challenges. Leaching from such large particles, especially over long time periods, is poorly understood. In this study, three large particle size classes ((25+19), (-16+9. 5), (-5+4. 75) mm) were prepared from a sphalerite ore from the Northern Cape, South Africa, by two different methods of comminution ( HPGR and cone crusher) and packed into leach reactors, which were operated continuously and well mixed through internal circulation of leach solution. Each reactor was inoculated by a mixed culture of mesophilic acidophilic chemolithotrophs (1.86 X 10 cell/kg ore) that was predominately L. ferriphilum and had been previously adapted to the sphalerite ore sample. Media with 1 g/L ferrous was used as continuous feed to the reactors. The pH, redox potential, Fe + and Fe + concentration as well as total Fe, Zn, Mg, Al and planktonic cell concentration in the effluent solution were measured regularly. The reactors were stopped from time to time to investigate the progress of leaching and also the colonisation of the surface of the ore particles by sessile cells was investigated. Planktonic and sessile microbial populations were monitored by quantitative real time polymerase chain reaction (qRTPCR). A comparison of the effect of the different comminution devices on metal extraction indicated that HPGR crushed ore leached more rapidly in all particle size classes. On average, larger particles showed a greater difference in the cell population densities ( HPGR crushed ore has more cell population) than the finer particles, and L. ferriphilum continued to dominate the microbial population over the course of leaching.
heap bioleaching sphalerite mesophilic acidophilic chemolithotrophs micro-organism
Yousef Ghorbani Jochen Petersen Olga V.Tupikina Susan T. L. Harrison Megan Becker Aubrey Mainza Jean-Paul Franzidis
Minerals to Metals Signature Theme, Department of Chemical Engineering,University of Cape Town, Priv Centre for Bioprocess Engineering Research (CeBER) Department of Chemical Engineering, University of Minerals to Metals Signature Theme, Department of Chemical Engineering,University of Cape Town, Priv
国际会议
The 19th International Biohydrometallurgy Symposium(第19届国际生物湿法冶金大会 IBS2011)
长沙
英文
249-257
2011-09-18（万方平台首次上网日期，不代表论文的发表时间）