China Nonferrous Metallurgy

In a high-arsenic and high-sulfur heavy mineral sand, partial gold minerals are associated with arsenic-bearing sulfide minerals, and the gold is often distributed in arsenopyrite in the form of wrapped micro-fine partciles or intergrowns with the arsenopyrite. Hence, it is quite difficult to obtain a high gold recovery index by conventional smelting method. According to the occurrence characteristics of gold in the heavy mineral sand, a combined process of mineral processing and metallurgy was investigated. The results show that a high-grade gold concentrate containing 35% of gold can be obtained by grinding and shaking bed gravity separation, which can be directly smelted and pre-recovered; after regrinding of tailings from shaking bed, biological oxidation pretreatment process is adopted; under the conditions of 10% feed concentration, 3.5mg/L dissolved oxygen and 9 days of biological oxidation, the arsenic oxidation rate is up to 98.52% and the sulfur oxidation rate is 94.29%. The total gold recovery in the combined process of shaking bed gravity separation + biological oxidation + cyanidation carbon in leach (CIL) process is up to 99.42%. Efficient recovery of refractory gold is realized in this study, providing technical reference for the recovery of gold from a high-arsenic and high-sulfur heavy mineral sand.