Recovery of Copper through Bioleaching from Copperslags in Kazakhstan

Kazakhstan is one of the large copper producers world wide. Copper is mostly produced by pyrometallurgy and copper slags deposited on site at steppe. The slag contains high amounts of valuable metals, e.g. zinc, iron, and silver. Material samples from a heap near Ust Kamenogorsk were analyzed with chemical and mineralogical methods. Some minerals detected are ferrosilite, andradite, chalcopyrite, charmosite, and tetrahedrite. The material was leached with A. ferroxidans, A. thiooxidans, Y. lipolytica, B. licheniformis and the fungus Kombucha. Copper is leached by B. licheniformis, iron and silver by Kombucha. Leaching success was detected using biochemical chelators. However, these results are based only on the very first experiments with the sample material.