Preparation of KVO₃ by Solventing-out Process

Potassium metavanadate(KVO₃) was firstly prepared by solventing-out crystallization,and the proper acidity range for crystallization from high-vanadium solution was determined.The results show that KVO₃ owning purity more than 98% can be obtained with vanadium recovery rate more than 95%,under the conditions of 150 g/L vanadium concentration,7.6~8.5 solution pH,ethanol as precipitation agent with volume ratio of 1:1 to the vanadium solution,and stirring for 60 min.The recovery rate for crystallization is closely related to the volume ratio of precipitation agent,vanadium concentration of mother liquor and crystallization time.The chromium content in the obtained crystals increases with rise in vanadium concentration of mother liquor and is not affected by crystallization time.However,the silicon content in the crystals decreases with increase in crystallization time and not change with vanadium concentration in mother liquor.Moreover,the particle size of crystals can be controlled by addition amount of precipitation agent.