PROCESS FOR THE HYDROMETALLURGICAL EXTRACTION OF PRECIOUS METALS FROM RAW MATERIAL THAT IS DIFFICULT TO PROCESS

摘要

The invention pertains to the metallurgy of non-ferrous and precious metals, more specifically, to a process for the hydrometallurgical extraction of precious metals from raw material that is difficult to process. The raw material matrix is crushed and placed in a sealed vessel containing a solution of halogen acids, nitrous acid and precious metal complex-forming agents. Oxygen is fed into the vessel from outside. During the process, the reaction mixture pH, pressure and half-wave oxidant reduction potential values are kept at predetermined levels; the process is continued long enough to ensure the break up of the raw material matrix to achieve maximum oxidation and extraction of the precious metals and form a mother liquor containing the dissolved precious metal complexes and oxides. The latter are extracted from the matrix and mother liquor by the known methods.