Extracting vanadium from stone coal with composite additive

According to the characteristic and petrographic analysis results of a stone coal, the composite additive roasting-dilute acid leaching technology was used to extract vanadium, so as to overcome the defects of heavy environmental pollution of sodium salt roasting, low leaching efficiency of single calcification roasting and useless of no-salt roasting to break the vanadium mica structure. Meanwhile, the technological parameter was optimized, the effect of roasting temperature, roasting time, usage and kinds of additive, usage of acid, liquid-solid ratio and leaching time on vanadium leaching efficiency were investigated. The results showed that valuable mineral in the ore were roscoelite, etc. Most of vanadium was in the state of V3+, V4+, and very few V5+, the ore was refractory. As to the grade of mixed stone coal raw ore of 0.81%, under the roasting temperature of 930, limestone of 6% and dolomite of 4%, roasting time of 12 h, acid of 8%, liquid-solid ratio of 2:1, leaching time of 2 h, the vanadium leaching efficiency was up to 76.51%. In summary, the vanadium could be availably extracted from stone coal by composite additive roasting technique, its economic and environmental benefits were notable.