Crystallization and Separation of Potassium Vanadate in Highly Concentrated Potassium Hydroxide Solution

The crystallization behavior of potassium vanadate from highly concentrated potassium hydroxide aqueous solution was investigated. The effect of various parameters including KOH concentration, V2O5 concentration, final crystallization temperature, cooling rate, stirring speed and additive amount of seed were examined. The optimal experimental conditions for K3VO4 crystallization were obtained as follows: KOH concentration 800 similar to 850 g/L, KOH-to-V2O5 mass ratio 8 similar to 9, stirring speed 200 r/min, crystallization temperature from 80 degrees C to 40 degrees C with natural cooling, and seed addition 2% wt. Under optimal conditions, the K3VO4 crystallization yield of 87% was obtained, and the purity of crystals was about 90%