湿法炼锌废电解液冷冻结晶除镁新工艺  

New process for removing magnesium from waste electrolyte of zinc hydrometallurgy using freezing crystallization

作　　者：江国豪 金鑫 李兴彬[1] 甑勇 魏昶[1] 邓志敢[1] 李旻廷[1] JIANG Guohao;JIN Xin;LI Xingbin;ZHEN Yong;WEI Chang;DENG Zhigan;LI Minting(Faculty of Metallurgical and Energy Engineering,Kunming University of Science and Technology,Kunming 650093,China;Sichuan Sihuan Zinc&Germanium Technology Co.Ltd.,Ya'an 625400,China)

机构地区：[1]昆明理工大学冶金与能源工程学院,云南昆明650093 [2]四川四环锌锗科技有限公司,四川雅安625400

出　　处：《中南大学学报（自然科学版）》2021年第12期4219-4226,共8页Journal of Central South University:Science and Technology

基　　金：国家重点研发计划项目(2018YFC1900402);国家自然科学基金资助项目(51664030,51804146,51964029)。

摘　　要：以湿法炼锌废电解液为原料,采用冷冻结晶方法选择性分离溶液中的硫酸镁,研究结晶温度、反应时间和硫酸质量浓度等因素对除镁行为的影响,获得冷冻结晶除镁的优化工艺技术参数,进一步分析结晶产物的化学组成和资源化利用途径。研究结果表明:降低结晶温度、延长反应时间以及增大硫酸质量浓度有利于提升结晶除镁效果;在结晶温度为-10℃、反应时间为90 min的优化工艺技术条件下,得到短棒状的含镁结晶产物,其中七水硫酸镁质量分数达到52.8%,实现了高酸条件下硫酸镁的选择性分离与富集。溶液中的镁离子质量浓度由结晶前的23.6 g/L降至结晶后的14.2 g/L,在结晶过程中硫酸不损失;含有硫酸和硫酸锌的结晶母液返回湿法炼锌系统循环利用。结晶产物可采用选择性中和沉淀法或高温还原挥发法进行资源化利用。Spent electrolyte of zinc hydrometallurgy(SEZH)was used as raw materials and freeze-crystallization was used to selectively remove magnesium sulfate form SEZH.The influences of crystallization temperature,reaction time and sulfuric acid mass concentration on the removal of magnesium sulfate were studied,optimum technological parameters of removing magnesium by freezing crystallization were obtained,and the chemical composition of crystallization product was investigated and the approach of resource utilization was discussed The results show that lowering temperature,prolonging reaction time and increasing sulfuric acid mass concentration are beneficial to the removal of magnesium from the SEZH.Under the optimized conditions of−10°C and reaction time of 90 min,rod-shaped magnesium-containing crystal product is obtained.The main phases in the crystallization products are magnesium sulfate heptahydrate and the mass fraction of magnesium sulfate heptahydrate reaches 52.8%.The aim of selective separation and concentration of magnesium sulfate from SEZH is achieved by freezing crystallization process.After crystallization,the magnesium ion in the solution decreases from 23.6 g/L to 14.2 g/L,while sulfuric acid maintains the same concentration.The crystallization mother liquor can be returned to zinc hydrometallurgy process for recycling.Besides,the crystallization products can be utilized by selective neutralization precipitation or high temperature reduction and volatilization method.

关 键 词：湿法炼锌 废电解液 冷冻结晶 除镁 

分 类 号：TF813[冶金工程—有色金属冶金]