PRESSURE OXIDATION OF SULFIDE GOLD-BEARING CONCENTRATES WITH DOUBLE REFRACTORINESS

摘要

Sulfide ores and concentrates have a special position among refractory gold-bearing raw material,rnin particular, gold-pyrite and gold-arsenic ones. According to the experts, their share is 30 per centrnfrom current world gold reserves.rnThe method of hydrometallurgical autoclave oxidation for gold and silver in sulfide concentratesrnis considered to be a long-range in the acidic media.rnIt was found that primary ores of a deposit in the Amur region (Russian Federation) are refractoryrnto cyanidation due to fine dissemination of gold into sulfides and carbonaceous matter content.rn30 per cent of gold is recovered by a direct cyanidation.rnPrimary ores possess 93 - 94 per cent of ore-forming minerals, such as quartz, hydromica, feldsparrnand 8 - 12 per cent of carbonates. Ore minerals are 2.7 - 2.8 per cent iron hydroxides and 4.5 - 5 perrncent sulfides. Pyrite is the main sulfide. Gold is the main valuable of the primary ores grade in thernamount 1.7 - 2.0 g/t.rnThe research was conducted on flotation concentrates obtained during large-scale and pilot plantrntests on the primary ore samples. They were tested according to various concentration flow sheetsrnsuch as I-II – with product flotation; III - without cleaner flotation.rnFlotation concentrates I, II and III obtained during various flotation flow sheets are characterizedrnby high sulfur content in the amount of 24-34 per cent. Gold grade is 24-32 g/t. Their autoclavernoxidation at the temperature of 220℃ and 2 h. duration allowed gold recovery to be increased byrn90 per cent.rnSulfur content decreasing in flotation concentrate III up to 14.9 per cent decreased gold grade uprnto 11.4 g/t. Autoclave oxidation – cyanidation of flotation concentrates I and II indices are muchrnhigher than gold recovery by autoclave followed by subsequent cyanidation of flotation concentraternIII (75.6 per cent). Thirty per cent of gold is recovered by the initial concentrate cyanidation. 80 perrncent of gold is recovered by direct cakes cyanidation and 90 per cent by sorption cyanidation.