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测定了KOHK3VO4H2O体系的溶解度,结合KOHK2CrO4H2O体系的溶解度变化规律,研究了KOHK2CrO4K3VO4H2O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630670g/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800850g/L,从80℃到40℃自然降温,在搅拌速度200r/min、晶种添加量2%()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.
The solubility of KOHK3VO4H2O system was determined, and the dissolution kinetics of KOHK2CrO4K3VO4H2O system was studied in combination with the change of solubility of KOHK2CrO4H2O system. The effect of K2CrO4 and K3VO4 crystallization separation parameters on the separation was studied.The results showed that the K2CrO4 crystal was isolated from K2CrO4 with KOH concentration of 630670g / L, the purity of K2CrO4 was above 90%, and the purity of the crystal was more than 95%. The crystallization mother liquor after separating K2CrO4 was further evaporated until the KOH concentration was 800850g / L, and the temperature was naturally cooled from 80 ℃ to 40 ℃. Under the optimal crystallization conditions of stirring rate of 200r / min and seed addition amount of 2% (), the crystallization rate of K3VO4 Is more than 60%, and the purity of the crystal is more than 90% .After the solution of K2CrO4 and K3VO4 is separated and returned, the vanadium slag sub-molten salt decomposition reaction process is recycled.