Chalcopyrite leaching with iodine (JX Iodine Process) for various ore types

Abstract

JX Nippon Mining and Metals Corporation developed the JX Iodine Process, which is an innovative and patented copper-leaching method for low-grade primary sulfide ores. The process consists of the irrigation of ferric iron and low-concentration iodide solutions. One-meter column leaching tests were conducted on a variety of ore types. The JX Iodine Process promoted Cu recovery in several ores compared with the conventional ferric leaching method. However, the Cu recovery was less improved when the ores contained high concentrations of calcite or Cu-soluble minerals. Even among the ores in which the chalcopyrite leaching was successfully improved, there was a notable difference in the improvement rate. Microscopic observations of the post-leaching residue cross-sections showed reaction vestiges around some chalcopyrite particles and even in the inner areas of the ores with high Cu recovery, which suggests that Cu recovery is sensitive to ore permeability. Scanning electron microscope observations indicate that the reaction vestiges were composed of elemental sulfur. The results of 6-m column leaching tests with a closed solution cycle also demonstrated the effectiveness of the JX Iodine Process.