Dissolution Behavior of Calcium Vanadates and Magnesium Vanadates in Sulfuric Acid

The dissolution efficiency of vanadium is the key to improve the recovery of vanadium from vanadium-bearing converter slag by calcification roasting-acid leaching process. An improved process, which involves roasting with calcium–magnesium salts, followed by acid leaching, was found to have a positive effect on the vanadium recovery. In this process, CaO–MgO–V2O5 is the basic system in the roasting step. In this study, the dissolution behavior of calcium vanadates (CaV2O6, Ca2V2O7, and Ca3V2O8) and magnesium vanadates (MgV2O6, Mg2V2O7, and Mg3V2O8) in sulfuric acid was investigated. The effect of parameters, such as stirring speed, solid/liquid ratio, and pH value, on the dissolution behavior of vanadates were determined. The results shown that both of solid/liquid ratio and pH value have significantly effects on the dissolution efficiency of vanadium, while stirring speed has a relatively minor effect under the studied conditions. Furthermore, the dissolution efficiency of magnesium vanadates has been found much higher than that of calcium vanadates.