Removal Techniques for Impurities in Acidic Ammonium Salt Precipitation of Vanadate

The impurities separation technology and the dissolution kinetics analysis of impurities in ammonium polyvanadate were studied, in order to solve the problem of high impurities content in ammonium polyvanadate prepared by acid ammonium salt precipitation from vanadium and sodium solution. The results show that ammonium polyvanadate having 50.25% of total vanadium content, 0.15% of Na₂O+K₂O and 0.13% of S can be gained by hot water immersion and washing at 5～7 of washing solution pH, 50～70 ℃ of wash temperature,（1.5～2.0）∶1 of liquid-solid ratio and 1%～2% of ammonium salt addition, with the vanadium recovery more than 99.60%. Moreover, the impurities separation process is kinetically controlled by solid film diffusion with 16.19 kJ/mol of apparent activation energy, based on the dissolution kinetics analysis of the impurities.