Keywords: bioleaching, chalcopyrite, mesophile microorganisms, thermophiles, catalytic ions, microbiological leaching, sulphide copper concentrate, copper recovery, bacterial leaching, sulphur dioxide
Microbiological leaching of chalcopyrite: an environmentally sound approach to processing a sulphide copper concentrate
Mineral sulphides are the main source of copper, from which this metal is recovered by pyrometallurgical processing after a flotation procedure. These processes generate high emissions of SO2 gases, which, in many cases, are discharged into the environment. The bioleaching method had been successfully used in copper recovery from low grade and secondary sulphide ores. Only recently, has it begun to be used to recover copper from its original concentrates because it is an environmentally and economically attractive alternative for copper recovery. In this paper, the results obtained by bioleaching tests of a flotation concentrate using mesophile bacteria and thermophiles with two different catalytic ions are presented. At high temperatures (thermophiles), the extraction reaches 95% in 10 days, while at low temperatures (mesophile bacteria) the extraction only reaches 42% in about 3 months of experimentation.