Autoclave processing of low grade copper-nickel concentrates

A chemical-mineralogical investigation of the behaviour of ore and rock-forming minerals of low grade nickel-bearing concentrates in sulphuric acid solutions has been carried out. A preliminary acidic treatment of the concentrates was carried out in an attempt to dissolve silicates and oxides and prepare the material surface for autoclave leaching. Conditions have been determined which correct the material composition at the leaching stage and change the acidity index to a value satisfying the requirements for autoclave decomposition. This makes it possible to achieve a higher degree of non-ferrous metal extraction and to accelerate the leaching process. The data obtained were used to develop a process for the autoclave leaching of non-ferrous metals in the presence of oxygen, followed by the separation of non-ferrous metals or their individual salts, as well as iron and magnesium.