提高硫酸化焙砂中金和铜浸出率的研究与实践

为了提高硫酸化焙砂中金和铜的浸出率,降低尾渣金品位,减少铜对氰化浸出过程的影响,考察了焙砂粒度、硫酸浓度、温度对硫酸脱铜率和脱铜渣氰化浸金率的影响。结果表明,焙砂(矿粉粒度-0.045 mm粒级占90.16%)在酸度25 g/L、液固比1.5∶1、80 ℃下浸出2 h,硫酸脱铜率达93.62%。脱铜渣在NH₄HCO₃用量10 kg/t、液固比1.5∶1、NaCN浓度0.10%条件下浸出60 h,金浸出率高达98.04%。根据研究结果,通过提高硫酸脱铜温度、硫酸浓度和氰化浸出过程增加旋流器和浸出槽数,采用两段浸出-两段洗涤措施,对现有生产流程进行了优化,铜和金回收率得到了明显提高,获得较好的经济效益。

Research and Practice for Improving Gold and Copper Leaching Rate from Sulfation-roasted Calcine

In order to improve Au and Cu leaching rate from the sulfation-roasted calcine, reduce the Au grade in tailings and lessen the influence of Cu on cyanidation leaching, effects of the grain size of calcine, the concentration of H₂SO₄ and temperature on the removal rate of Cu with sulfuric acid, as well as Au leaching rate from the obtained residue by cyanidation were investigated. Results showed that the calcine (at the fineness of -0.045 mm 90.16%) was subjected to a 2-h leaching process at a temperature of 80 ℃ with acidity of 25 g/L, liquid to solid ratio at 1.5∶1, resulting in the Cu removal rate by sulfuric acid at 93.62%. The obtained residue went through a 60-h leaching with NH₄HCO₃ dosage at 10 kg/t, liquid to solid ratio at 1.5∶1, NaCN concentration of 0.10%, the gold leaching rate was as high as 98.04%. Based on the research results, the existing production process was optimized by raising the temperature for Cu removal and increasing H2SO4 concentration, as well as adding more cyclones and leaching tanks in the cyanidation leaching process, also adopting process of two-stage leaching plus two-stage washing, which resulted in both Cu and Au recovery rates remarkably improved and brought in better economic benefits.