锌浸渣和锌焙砂铜粉还原浸出工艺研究

Research on Cu-assisted leaching process of zinc leaching residue and zinc calcine

为了减少传统锌冶炼浸出渣渣量,同时提高金属回收率,本研究以锌浸渣和锌焙砂为研究对象,研究了添加铜粉的还原浸出工艺。控制铜粉足量,详细考查了硫酸浓度、液固比、反应温度和硫酸酸量对锌浸渣和锌焙砂锌浸出率,渣率和反应后浸出液尾酸的影响规律。结果表明,相比单纯的酸浸,相同反应条件(硫酸100 g/L、液固比20 mL/g、60℃)下,铜粉还原浸出可使锌浸渣的锌浸出率从32.82%提高至92.82%,渣率由62.34wt%降低至25.20wt%,反应后浸出液pH由0.12升高至0.36;相同反应条件(硫酸200 g/L、液固比10 mL/g、60℃)下,铜粉还原浸出可使锌焙砂的锌浸出率由86.52%提高至98.82%,渣率由26.56wt%降低至6.28wt%,反应后浸出液pH从低于0升至0.19。在获得较高锌浸出率的条件下,锌浸渣和锌焙砂的反应浸出液尾酸浓度最低为25~26 g/L。铜粉还原浸出工艺实现了中温条件锌的高效浸出,同时大幅降低锌浸出渣渣量,不残余大量尾酸,可为就地处理锌浸渣提供新思路。

To reduce the amount of zinc leaching residue and improve the metal recycling rate in the traditional zinc smelting process,a Cu-assisted reductive leaching process of zinc leaching residue and zinc calcine was proposed in this study.In the presence of sufficient copper powder,effect of factors including sulfuric acid concentration,liquid-solid ratio,leaching temperature,and the amount of H2SO4 on the zinc leaching efficiency,the residual rate of the solid,and the residual amount of H2SO4 for zinc leaching residue and zinc calcine was investigated.The results of leaching experiment showed that for zinc leaching residue,the zinc leaching efficiency was enhanced from 32.82%to 92.82%assisted by copper,compared to the pure acid leaching process(100 g/L H2SO4,20 mL/g,60℃).The residual rate of the solid was decreased from 62.34wt%to 25.20wt%.Values of pH of the leaching solution were increased from 0.12 to 0.36.For zinc calcine,the zinc leaching efficiency was enhanced from 86.52%to 98.82%assisted by copper,compared to the pure acid leaching process(200 g/L H2SO4,10 mL/g,60℃).The residual rate of the solid was decreased from 26.56wt%to 6.28wt%.Values of pH of the leaching solution were increased from 0 to 0.19.The least concentration of the residual H2SO4 was 25~26 g/L for sufficient extraction of zinc.The Cu-assisted leaching process has advantages in metal recycling,residue reduction,and low concentration of the residual H2SO4.It supplies a new idea about in situ treatment of zinc leaching residue in zinc smelters.