Intensification of the Bio-oxidation Process of Axi Refractory Gold Concentrate

In order to enhance the efficiency of bio-oxidation of Axi gold concentrate, the effects of three mixed bacteria cultures and two-step treatment approach on the intensification of bio-oxidation were studied. The results revealed that the optimum mixed culture was moderate thermophiles, the oxidation rates declined drastically with increasing of pulp density. The extraction rates of iron and sulfur were 98.35% and 91.90% at 2% pulp density, when the pulp density was elevated to 15%, the extraction rates of iron and sulfur declined to 50.25% and 49.51%, respectively. The two-step treatment could further improve the efficiency of pretreatment with moderate thermophiles, the extraction rates of iron and sulfur boosted to 64.93% and 65.73% at 15% pulp density after the two-step treatment, which was equivalent to the result obtained at 10% pulp density with normal bio-oxidation process.