高镁硫酸锌溶液氟化沉淀脱镁工艺优化

Process optimization of magnesium removal from high-magnesium zinc sulfate solution by fluorination precipitation

  • 摘要: 氟化沉淀法是湿法冶炼过程中最有效的脱镁技术之一,但该方法存在氟引入量大、难以过滤的问题。基于此,本文在理论计算的基础上,开展了氟化物沉淀法脱除硫酸锌溶液中镁的研究,通过溶液成分分析和沉淀渣物性表征,探讨了沉淀后液和沉淀渣处理方案。结果表明,加料方式和反应温度对氟引入和沉淀渣过滤性能影响较为显著。以氟化锌为沉淀剂,采用反向加料,在氟镁比为0.75(氟化锌用量为21.88 g),温度为60 ℃,加料时间为16 min条件下,镁的脱除率可达64.42%,除镁后液中氟浓度仅为0.22 g/L。利用La(OH)3可有效脱除除镁后液中的氟,除氟率可达82%以上。利用纯水洗涤2次后,可将除镁渣中的锌从17.12%降至0.67%,所得洗涤渣成分满足工业氟化镁技术指标(YS/T 691—2009)。

     

    Abstract: Fluoride precipitation is considered one of the most effective techniques for magnesium removal in hydrometallurgy. However, this method has the problem of introducing a large amount of fluorine introduction and poor filtration performance of precipitates. Given this, the theoretical calculations of the fluoride precipitation were carried out. Then, the removal of magnesium from zinc sulfate solution by the fluoride precipitation method was investigated through the characterization of the solution composition precipitates, and the treatment of the precipitated liquid and precipitates. The results showed that the feeding modes and reaction temperature significantly affected the fluorine introduction and filtration performance of precipitates. Under the conditions of a fluorine-magnesium ratio of 0.75 (zinc fluoride dosage of 21.88 g), a temperature of 60 °C and a feeding time of 16 min, the removal rate of magnesium could reach 64.42%. In contrast, the fluorine concentration in the liquid after magnesium removal was only 0.22 g/L. Fluoride in the final liquid could be effectively removed using La(OH)3, and its removal rate could reach more than 82%. After washing twice with pure water, the zinc in the washing products could be reduced from 17.12% to 0.67%, which can meet the technical specifications of industrial magnesium fluoride (YS/T 691—2009).

     

/

返回文章
返回