Extraction Behavior of Vanadium and Chromium by Calcification Roasting-Acid Leaching from High Chromium Vanadium Slag: Optimization Using Response Surface Methodology

Calcification roasting-acid leaching were conducted to investigate the extraction behavior of vanadium and chromium from high-chromium vanadium slag (HCVS). The conditions were optimized by response surface methodology (RSM). Results showed that when HCVS and CaO were mixed in m(CaO)/m(V2O5) of 0.62, then roasted from room temperature to 840 °C and maintained for 170 min, a maximum vanadium leaching rate of 87.74% was achieved. Additionally, 0.68% chromium was co-leached, achieving the separation of vanadium and chromium. The roasting factors affecting vanadium extraction followed this order: roasting temperature>m(CaO)/m(V2O5)=holding time. For the chromium extraction, the interaction between m(CaO)/m(V2O5) and roasting temperature was significant.