Influence of the ore reduction method on the percolation leaching efficiency

This paper covers gold leaching from sulfide ores. The data on the silicate, mineral, and grain-size composition are presented for the ore studied. Agitation leaching studies were completed for the combined sample and direct cyanidation dynamics indicators are established for the material sample. For all material with the grain size class of 95 % passing –0.074 mm, the required agitation leaching duration is 9–10 hours; with the material sizes up to 2 mm, the leaching duration shall be at least 22 hours. In order to study the efficiency of using roller presses as an alternative to fine crushing, two percolation leaching tests were conducted for the ore size of –5 mm. The material for the first test was prepared by crushing in a standard jaw crusher and the material for the second test was prepared by crushing in a laboratory press with complex monolayer reduction. It has been found that ore reduction using high-pressure crushers, as compared to standard crushing equipment, allows increasing gold recovery during subsequent leaching by 13.52 %. At the same time, the consumption of sodium cyanide increases by 0.26 kg/t of ore.