Development of an Approach to the Extraction of Non-ferrous Metals from Mature Copper-nickel Tailings by Heap Leaching Method

The engineering and geological properties of the surface layer of the tailing dump, mineral and chemical composition of tailings were studied, the probability of nickel ions migration to the adjacent water bodies was shown, the scheme of tailings processing by means of preliminary granulation and subsequent leaching using water, sulfuric acid solution and bacterial solution was proposed. It is confirmed that the application of 10% sulfuric acid solution as a binder using nitrite ion as an oxidizing agent allows to recover more than 50 % of nickel and 47.8 % of copper at the heap leaching stage. It is shown that 11.6 % of nickel and 13.5 % of copper are recovered by bioleaching of tailings pellets prestrengthened with polymer binder.