Mechano-chemical treatment of tetrahedrite as a new non-polluting method of metals recovery

Abstract

Laboratory investigations were performed with tetrahedri-te concentrate from l-Iaria-Rozi'iava mine in Slovakia having the chemical composition of 21% Cu, 115~ Sb, 28~b S, 1~~ As, 2~ Zn, O. 2$~ Ag and 1% Hg. X-ray analysis reveal follo;.;ing proportions of dominating phases: 41% Tetrahedrite (CU 12 Sb 4 S j ,,), 12~b Chalcopyrite (CuFeS 2) and 251~ Pyrite (Fes 2). Cfiamical leaching tests with Na 2 S-solutions indicate that only half of the antimony in the concentrate can be recovered, whereas mechano-chemical leaching in a stirred ball mill under similar leaching conditions a nearly complete and selective antimony extraction is achieved. According to X-ray analysis the increased extraction by mechano-chemical leaching might be related beside the grinding action to the transformation of tetrahedrite into covelite (CuS), Depending on the degree of disorder in tetrahedrite the chemical and bacterial leaching of the solid residues after mechano-chemical treatment with CS(NHZ)2/FeZ(SOLL)'l so~ution si~ver recoveries from 50-90~~ and w1tfi Th10baci~lus ferrooxidans-medium copper recovery was 74-84%.