硫酸溶液中での黄銅鉱浸出に対する活性炭と石炭の触媒作用

Abstract

Activated carbon is known as a catalyst for chalcopyrite leaching in sulfuric acid solutions. This paper compares the effects of six different activated carbon samples on copper extraction from a chalcopyrite concentrate by shaking flask leaching experiments at 303 K under atmospheric conditions. Eight different coals were also evaluated as an alternative to activated carbon.Except for one activated carbon sample, activated carbon addition enhanced copper extraction. Increases in the weight ratio of activated carbon to the chalcopyrite concentrate caused increases in copper extraction. The effects of the coals on copper extraction were related to the rank of the coals: Low rank coals like brown coal, which have low fixed carbon contents and high contents of volatile matter, suppress copper extraction, and high rank coals, which contain more fixed carbon and less volatile matter, enhance copper extraction. High rank coals stored under atmospheric conditions over long periods (more than 7 months) suppressed copper extraction, implying that oxidation of the coal surface and its products cause the suppression in copper extraction.The experimental results are analyzed and discussed with a reaction model for the redox potential dependence of chalcopyrite leaching, which assumes the formation of intermediate Cu2S by chalcopyrite reduction and a subsequent oxidation of the Cu2S.