Respirometry studies of the bioleaching of a copper ore in large columns—effect of changing temperatures
During a series of large-scale column tests on a lowgrade mixed sulphide copper ore, the concentrations of both oxygen and CO2 were continuously monitored in feed and exit gas, as well as at various intermediate positions over the height of a 6 m column. While in a previous study we have focused on an isothermal column run at 40°C , we compared the results obtained from column experiments run where the column temperature was controlled such as to mimic the heating experienced by the ore due to the ongoing bioleaching reactions. Experiments were conducted with ambient air and air enriched to 8000 ppm CO2. The results indicate that the column supplied with enriched air leached significantly faster than the one operated on air, but both reached thermophilic conditions which facilitate chalcopyrite leaching. In the column run on air leaching progressed zone-wise up the column as microbial activity tended to consume all available C02, not leaving enough for zones higher up. Nonetheless the heating due to oxygen consumption was sufficient to drive each zone into the thermophile region where initial leaching ceased once temperatures exceeded 55 -60X1. Further analysis shows there is a strong correlation between oxygen and CO2 consumption rates which can be described by a linear relationship with yield and maintenance terms. These are different for microbes in growth and stationary phases, for mesophile and thermophile cultures and they are also a function of the local CO2 concentration. Implication for heap bioleaching is that CO2 enrichment to drive a heap rapidly into the thermophile regime may be advisable.
heap bioleaching column leaching respirometry CO2 oxygen yield coefficient
Jochen Petersen Sanet H. Minaar Chris A. du Plessis
Center for Bioprocess Enginering Research (CeBER), Department of Chemical Engineering, University of Vale, Mineral Technology, 96 Outram Street, West Perth WA6005, Australia
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
53-58
2011-09-18（万方平台首次上网日期，不代表论文的发表时间）