Effects of Turbomilling Parameters on the Simultaneous Grinding and FerricSulfate Leaching of Chalcopyrite

摘要

As part of its mission, the U.S. Bureau of Mines continues to developtechnologies that will enable cost-effective compliance with environmental requirements. To the end, investigations to improve the kinetics of chalcopyrite dissolution by simultaneous grinding-leaching in ferric sulfate solution were conducted using the Bureau-designed turbomill. The development of such a hydrometallurgical process would provide a nonpolluting alternative to conventional smelter technology. The effects of mill rotational speed and volume percent solids on the leaching time and energy required for copper extraction from chalcopyrite were evaluated. The results of the laboratory study have shown that the simultaneous grinding-leaching of chalcopyrite concentrate using the turbomill is technically feasible with essentially 100 pct extraction of copper being possible at 90 C. An optimal energy consumption of 1,153 kW.h/st of copper leached was found in batch testing with the mill operating at 400 rpm with a slurry containing 35 vol pct chalcopyrite. The energy consumption, while higher than other proposed leaching processes (about 600 kW.h/st), is of the same order of magnitude. Further refinement of the energy requirements would require additional testing using a continuous circuit. Leaching times of less than 1 h, for 80 pct copper extraction, are achievable using the turbomill grind-leach process.