湖南某难处理金矿的加压预氧化-氰化浸金试验研究

针对湖南某难处理金精矿进行预处理技术研究.该矿含砷(质量分数)为11.28%,金的直接氰化浸出率为21.91%.矿石中的砷以毒砂形式存在.载金矿物为毒砂和黄铁矿等硫化物,金为微细浸染型被毒砂和黄铁矿包裹.通过加压预氧化,对矿石进行氰化浸金试验研究.加压氧化最佳条件为初始酸度1 mol/L,木质素磺酸钠5 g/t,硝酸硫酸比7∶1,氧压0.6 MPa,搅拌速度300 r/min,时间100 min,温度100℃,矿浆浓度20%.试验表明经过加压试验后,金的氰化浸出率达到90.87%,与未预处理相比提高了68.96%,达到了较好的试验效果.

Experimental Investigation on Pressure Preoxidation for Refractory Gold Concentrate in Hunan with Cyaniding Leaching

The preprocessing technique for a refractory gold concentrate in Hunan Province PRC was investigated experimentally, which contains 11.28% arsenic and its direct cyaniding leaching rate of gold is 21.91%. The occurrence form of arsenic in concentrate is mainly the arsenopyrite, and the gold-bearing minerals are arsenopyrite and pyrite, where the minutely dipped gold grains are wrapped up by arsenopyrite and pyrite. After pressure preoxidation, an experiment was done to extract gold from refractory gold concentrate by cyaniding leaching. The optimal conditions for pressure preoxidation are: Initial acidity is 1 mol/L, content of sodium lingosulfonates 5 g/t, ratio of HNO3 to H2SO4 is 7:1, pressure 0.6 MPa, stirring speed 300 rpm, processing time 100 min at 100°C and sampling pulp density 20%. The results showed that after the pressure preoxidation, the cyaniding leaching rate of gold comes to 90.87%, i.e., 68.96% is increased in comparison with the process without pressure preoxidation.