Bacterial Leaching of Low Grade Iranian Copper Ores

摘要

The national Iranian copper industry (N.I.C.I Co.) is constantly seeking new and more practical technologies to treat low-grade ores and increase profitability, while operating in times of low copper prices and increased environmental concerns The total mine able reserves of the Iranian copper ore deposits are estimated to be about 2000 Mt with an average copper grade of about 0.7% Including the low grade deposits with an average copper grade between 0.2% and 0.4%, the estimated reserves would increase significantly. Therefore, the primary objective of this paper was, to improve the understanding of the key technological parameters of bacterial leaching of mixed ores and to use this understanding for identifying the optimum conditions under which bioleaching can be applied to extract copper from low grade Iranian ores. Within the scope of this study, several tests were performed, using low grade Iranian copper ores and mixed cultures of mesophilic and moderate thermophilic bacteria Mineralogical and chemical composition of samples to be leached, microbiological properties of bioleaching environment and processing parameters were considered in the investigations. From the results of these tests, it appears, that using mixed cultures at optimum conditions more than 80% of copper could be recovered from low grade mixed copper ores. Therefore, microbial leaching can be considered as an alternative process for extraction of copper from low grade Iranian deposits and flotation tailings In both cases, the copper recovery should be high enough to justify the process economically. However, to define the optimum conditions for commercial use of bio-heap leaching in Iran, further investigations are necessary.