Fundamental studies have been made on the hydrometallurgical treatments of complex sulfide ores, especially on the selective leaching of zinc minerals.For this purpose the solution potential of the sulfide mineral suspension was measured by platinum electrode and saturated calomel electrode, both being immersed in the solution.The potential values measured for cuprous and cupric sulfides and pyrite corresponded approximately to the mineral-electrode potentials (theoretical values) given in the literature. The relation between the potential and the dissolution pct.at 97°C and with 1M sulfuric acid solution was investigated for simple sulfide minerals such as pyrite, chalcopyrite, covelline, bornite, and chalcocite.The results showed that the potential values for copper dissolution were about 400 mV for chalcopyrite, about 330mV for CuS, and about 240mV for Cu2S in the primary stage.
Consequently, for preventing of the dissolution copper it is necessary to treat complex sulfide ores under the respective potential mentioned above.The similar experiments with sphalerite and galena were also carried out.But, as these minerals dissolve with the evolutions of H2S, the mode of dissolution of the minerals is quite different from that of the copper-iron sulfide minerals mentioned above.
