A process of biooxidation followed by thiosulfate leaching of gold from refractory gold concentrate was investigated. Mineralogical studies on the concentrate showed that very fine gold grains (<10 µm) were encapsulated in pyrite and arsenopyrite, while the proportion of monomer gold was only 21%. The gold-bearing sample was identified as a high-sulfur fine-sized wrapped-type refractory gold concentrate. The gold leaching efficiency obtained by direct cyanidation was only 59.86%. After biooxidation pretreatment, the sulfide minerals were almost completely decomposed, 92wt% of the mineral particles of the biooxidation residue were decreased to <38 µm, and the proportion of monomer gold in the biooxidation residue was over 86%. Meanwhile, the gold content in the biooxidation residue was enriched to 55.60 g/t, and the S, Fe, and As contents were reduced to approximately 19.8wt%, 6.97wt%, and 0.13wt%, respectively. Ammoniacal thiosulfate was used for gold extraction from the biooxidation residue of the refractory gold concentrate. The results showed that the optimal reagent conditions were 0.18 M thiosulfate, 0.02 M copper(II), 1.0 M ammonia, and 0.24 M sulfite. Under these conditions, a maximum gold leaching efficiency of 85.05% was obtained.

研究了生物氧化过程，然后从难处理的金精矿中硫代硫酸盐浸出金。对精矿的矿物学研究表明，非常细的金晶粒（<10 µm）被包裹在黄铁矿和毒砂中，而单体金的比例仅为21％。含金样品被鉴定为高硫细粒包裹型耐火金精矿。通过直接氰化获得的金浸出效率仅为59.86％。经过生物氧化预处理后，硫化物矿物几乎完全分解，生物氧化残渣中的矿物颗粒的92wt％减少至<38 µm，生物氧化残渣中单体金的比例超过86％。同时，生物氧化残留物中的金含量增至55.60 g / t，而S，Fe，砷的含量分别降低到约19.8wt％，6.97wt％和0.13wt％。氨硫代硫酸盐用于从难熔金精矿的生物氧化残余物中提取金。结果表明，最佳试剂条件为0.18 M硫代硫酸盐，0.02 M铜（II），1.0 M氨水和0.24 M亚硫酸盐。在这些条件下，获得的最大金浸出效率为85.05％。