混合酸溶液浸出刚玉烟尘灰中的镓

摘要

为了从高硅含量的刚玉冶炼烟尘中提取镓,提出一种硫酸与氢氟酸混合酸溶液浸出的方法,并对浸出过程的各项实验参数进行优化.结果显示,当单独使用硫酸作为浸出剂时,刚玉烟尘中镓的浸出率仅为38％.从刚玉烟尘灰的微区成分分析结果中可知,烟尘中的富硅相镓含量较高;这部分镓无法溶入硫酸溶液.氢氟酸的加入对二氧化硅产生侵蚀,从而显著提高了刚玉烟尘灰中镓的浸出率.研究反应时间、温度、氢氟酸浓度和硫酸浓度对镓浸出率的影响.结果表明,在最佳浸出条件下,烟尘中镓的浸出率可达到91％.最佳的浸出参数如下:反应时间4h、反应温度80℃、混合酸溶液中硫酸浓度1.5 mol/L、氢氟酸浓度6.4 mol/和液固比5∶1 (mL/g).%In order to extract gallium from a high-silica-content flue dust generated in corundum production,a mixed acid solution of H2SO4 and HF was used for leaching,and test parameters of the leaching process were optimized.Experimental results show that the leaching rate of gallium was only 38％ when H2SO4 was used as leaching agent.Composition analysis results of micro areas in this corundum flue dust indicate that the content of gallium in silica-enriched phases was high;this portion of gallium was insoluble in H2SO4 solution.The leaching rate of gallium increased significantly with addition of HF due to corrosion of silica.Effects of reaction time,temperature,and concentrations of HF and H2SO4 on leaching rates of gallium were investigated.The leaching rate of gallium reached 9 1％ when this corundum flue dust was leached in a mixed acid solution of H2SO4 and HF for 4 h,at a temperature of 80 ℃,with a liquid-to-solid ratio of 5∶1 (mL/g).The optimal concentrations of H2SO4 and HF in the mixed acid solution were 1.5 and 6.4 mol/L,respectively.