Copper-zinc ore leaching in electrochemically modified dump water
The best part of off-grade copper-zinc ore and waste is composed of sulfide minerals leaching of which requires, aside from the prime dissolver, strong oxidants such as salts Fe <sup>3+</sup>, hydric dioxide, sodium hypochlorite, oxygen, ozone and others that promote oxidation of sulphide sulphur to SO <sub>4</sub> <sup>2-</sup> ions and contribute to nonferrous metal transition to liquid phase. The studies have shown possibility of the copper-zinc ore leaching stimulation using the chemically-electrochemically modified dump water in the capacity of the dissolver for the dump water is characterized by the high concentration of oxidizers (up to 1/5 g/dm <sup>3</sup>). This leaching technology allows the required copper and zinc concentration in pregnant solutions for the follow-on processing: the copper and zinc concentration becomes 1.5-3.0 g/dm <sup>3</sup> at the copper recovery growth by 20% (from 66.2 to 86.6%) and the zinc recovery growth by 14.4% (from 28.6 to 43.0%) as compared with the sulphuric acid leaching. The development laboratory at the processing plant of the Uchalinsky Mining-and-Processing Integrated Works JSC conducted a trial of the new leaching technology using copper-zinc ore sampled at the Uchalinsky, Sultanovsky and West Ozerny deposits characterized by different degree oxidation of copper minerals. The trial confirmed high efficiency of the electrochemically modified dump water that increased copper and zinc concentration in pregnant solutions from 0.01-0.81 to 1.18-1.85 g/dm <sup>3</sup> as against the sulphuric acid leaching.