Effects of Vanadium-containing Slag Calcium Roasting Conditions on Leaching Rate of Vanadium
钒渣钙化焙烧参数对钒浸出率的影响

Based on the analysis of reaction mechanism of vanadium-containing slag(V2O3 8.07%) calcium roasting process,the effects of various factors on vanadium leaching rate were investigated by means of calcium roasting coupled with acid leaching.The results showed that various calcium vanadates namely CaV2O6,Ca3V2O8,CaV3O7 would form between V2O5 and CaO at 600-900℃.The acid leaching of roasted slag indicated that the mass ratio of CaO to V2O3 in the roasted slag played an important role in the roasting process.Vanadium leaching rate increased from 55.3% to 69.2% when the ratio was from 0.48 to 1.125,while the rate decreased when the ratio exceeded 1.125.When the roasting temperature increased from 750 to 825℃,the leaching rate from 56.3% to 69.7%.However,the slag roasted the temperature higher than 825℃ lead to the decrease of leaching rate.Vanadium leaching rate increased with the roasting time.The maximum rate was achieved when the roasting time was 2 h.With longer roasting time,the slag reacted further,leading to the decrease of vanadium leaching rate.