金精矿浸出含氰废水的处理

国外某金矿金精矿浸出过程产生的含氰废水采用七水合硫酸亚铁法处理后可直接返回浮选生产,对浮选指标影响小。在最佳试验条件下,即七水合硫酸亚铁调节废水pH值至5.5~6.5,用量1.5~1.7 kg/m~3,充气搅拌处理6 h,处理后溶液中无游离CN~-。处理后溶液回水返回浮选闭路试验获得金精矿金品位16.04 g/t、金回收率96.64%,浮选指标与清水浮选闭路试验指标相近。处理后溶液利用焦亚硫酸钠去除总氰化物,焦亚硫酸钠加入量0.5~1.5 kg/m~3,石灰调节pH值7~9,充气搅拌处理6 h,试验可将总氰化物质量浓度降至0.30 mg/L以下。

Study on the treatment of cyanide wastewater produced in gold concentrate leaching process

The wastewater produced in the cyanide leaching process of gold concentrates from a overseas gold mine is treated with ferrous sulfate heptahydrate and afterwards can directly return to flotation production while has little impact on the flotation index.Under optimal conditions,i.e.cyanide wastewater pH adjusted by ferrous sulfate heptahydrate is 5.5-6.5,the dosage of ferrous sulfate heptahydrate is 1.5-1.7 kg/m3,the wastewater is stirred and aerated for 6 h,the treated solution has no free CN-.The treated solution returned to the flotation closed circuit test,where the gold concentrate grade obtained is 16.04 g/t and gold recovery rate is 96.64 %,which are close to the index obtained in the closed circuit using clean water.The treated solution uses sodium metabisulfite to remove cyanide.When the dosage of sodium metabisulfite is 0.5-1.5 kg/m3,pH adjusted by lime is 7-9,and the solution is aerated and stirred for 6 h,the test can reduce total cyanide mass concentration to below 0.30 mg/L.