A gold ore with high pyrite content(5.31%)and low oxidation rate(6.02%)belongs to a typical low-grade refractory sulfidic gold-bearing ore,the gold leaching rate by a direct cyanide-leaching was only 27.78%.In order to evaluate the industrial application prospect of bio-preoxidation heap leaching process,direct cyanide leaching test,bio-stirring pre-oxidation test and bio-column leaching test were carried out to investigate the relationship between pyrite oxidation rate and gold leaching rate and the effect of temperature on pyrite oxidation rate and gold leaching rate.The results of bio-column leaching test showed that under the conditions of D80=5.5 mm and at room temperature(8-30℃),about 52.30%of the pyrite was oxidized after 221 days,the leaching rate of gold came to 62.70%,which was 34.92 percentage points higher than that of direct cyanide leaching(27.78%),and the gold grade of leaching residue can be decreased to 0.47 g/t.
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