Welcome to visit The Chinese Journal of Process Engineering, Today is

›› 2012, Vol. 12 ›› Issue (3): 402-408.

• 反应与分离 • Previous Articles     Next Articles

Efficient Crystallization Separation of K2CrO4 and K3VO4 in Alkaline Multi-component System of KOH Medium

YANG Na WANG Shao-na DU Hao QIN Ya-ling ZHENG Shi-li WANG Shao-na   

  1. National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Inst. Process Eng., Chinese Academy of Sciences Institute of Process Engineering, Chinese Academy of Sciences Institute of Process Engineering, Chinese Academy of Sciences Institute of Process Engineering, Chinese Academy of Sciences Institute of Process Engineering, Chinese Academy of Sciences Institute of Process Engineering, Chinese Academy of Sciences
  • Received:2012-04-20 Revised:2012-05-11 Online:2012-06-20 Published:2012-06-20
  • Contact: YANG Na

KOH介质多元体系中铬酸钾与钒酸钾的高效结晶分离

杨娜 王少娜 杜浩 秦亚灵 郑诗礼 张懿   

  1. 中国科学院过程工程研究所湿法冶金清洁生产技术国家工程实验室 中国科学院过程工程研究所 中国科学院过程工程研究所 中国科学院过程工程研究所 中国科学院过程工程研究所 中国科学院过程工程研究所
  • 通讯作者: 杨娜

PDF

Abstract: The solubility of KOH-K3VO4-H2O system was determined. Based on the solubility variation of KOH-K3VO4-H2O and KOH-K2CrO4-H2O systems, the separation method of K2CrO4 and K3VO4 by evaporation crystallization and cooling crystallization respectively from KOH-K2CrO4-K3VO4-H2O system was established. Aiming at the digestion liquor obtained by the sub-molten salt decomposition reaction, the effects of process parameters on crystallization separation of K2CrO4 and K3VO4 was studied. The results showed that K2CrO4 was separated when the KOH concentration of digestion liquor was evaporated to 630~670 g/L. The crystallization rate of K2CrO4 was more than 80%, and its purity over 95%. The mother liquor was continuously evaporated, the optimal experimental conditions for the separation of K3VO4 were obtained: KOH concentration 800~850 g/L, temperature from 80℃ to 40℃ with natural cooling, stirring speed 200 r/min, seed load 2%(w). Under the conditions, the crystallization rate of K3VO4 was more than 60%, and its purity over 90%. The solution after the separation of K2CrO4 and K3VO4 was recycled for the sub-molten salt decomposition reaction.

Key words: K2CrO4, K3VO4, KOH, sub-molten salt, crystallization separation

摘要： 测定了KOH-K3VO4-H2O体系的溶解度，结合KOH-K2CrO4-H2O体系的溶解度变化规律，研究了KOH-K2CrO4-K3VO4-H2O四元体系中蒸发结晶分离K2CrO4和冷却结晶分离K3VO4的方法. 针对钒渣钾系亚熔盐分解获得的溶出液组成，研究了该体系中K2CrO4和K3VO4结晶分离工艺参数对分离效果的影响. 结果表明，将溶出液蒸发至KOH浓度为630~670 g/L进行K2CrO4分离，K2CrO4结晶率达90%以上，晶体纯度达95%以上；将分离K2CrO4后的结晶母液继续蒸发至KOH浓度为800~850 g/L，从80℃到40℃自然降温，在搅拌速度200 r/min、晶种添加量2%(w)的优化结晶条件下，K3VO4结晶率为60%以上，晶体纯度达90%以上. 分离K2CrO4和K3VO4后的溶液返回钒渣亚熔盐分解反应过程循环使用.

关键词: 铬酸钾, 钒酸钾, 氢氧化钾, 亚熔盐, 结晶分离

CLC Number: