冶炼含氟废酸制备冰晶石的工艺优化

Optimization on Preparation of Cryolite from Waste Smelting Acid Containing Fluoride

以冶炼含氟废酸为原料,通过中和除杂、合成反应和洗涤烘干等工艺制备冰晶石。考察了中和除杂pH值对金属离子去除率的影响及反应pH值、投料比Na∶Al∶F、反应温度、反应时间对氟回收率和剩余氟离子浓度的影响,并通过XRD、EDAX、SEM对产品的物相和形貌进行了表征。结果表明,在中和除杂pH值为7.5、反应pH值为8.0、投料比Na∶Al∶F为4∶1∶6、反应温度为80℃、反应时间为60min的最优条件下,氟回收率可达98.9%,剩余氟离子浓度可降至200mg·L^(-1);制得的冰晶石产品质量达到GB/T 4291-2007的要求,钠铝物质的量比为2.5。实现了冶炼含氟废酸的资源化利用。

Using waste smelting acid containing fluoride as a raw material,cryolite was prepared by neutralization and purification,synthetic reaction,washing and drying.The effect of pH value of neutralization and purification on the removal rate of metal ions,and effects of reaction pH value,reactant ratio Na∶Al∶F,reaction temperature,reaction time on the recovery of fluoride and the residual fluoride ion concentration were investigated.The phase and morphology of the products were characterized by XRD,EDAX,SEM,respectively.Results indicated that,when pH value of neutralization and purification was 7.5,reaction pH value was 8.0,reactant ratio Na∶Al∶F was 4∶1∶6,reaction temperature was 80 ℃,reaction time was 60 min,the recovery of fluoride reached 98.9%,and the residual fluoride ion concentration decreased to 200mg·L-1.The quality of prepared cryolite met the requirement of GB/T 4291-2007,while the molar ratio of Na and Al was 2.5.This study implements resource utilization of waste smelting acid containing fluoride.