Studies on Direct Leaching of Complex Sulfide Ores.

Laboratory experiments were performed in order to define the optimal conditions for direct leaching of some complex sulfide ores. The results thus obtained show that satisfactory recovery of copper and nickel from sulfide ore concentrates is achieved only after crushing and grinding of the ore. A selective separation of nickel is not possible with this technique. Zinc can be removed from copper-zinc concentrates without any mechanical pretreatment provided that ferric ions are present in the system and leaching is carried out at 90-100 degree C. Copper from these concentrates can be extracted in a second leaching stage following mechanical treatment. Based on the results of this work it is recommended to carry out the leaching process in an autoclave at 110 degree C, under oxygen pressure of 10 bar.