Kinetics of Oxygen Pressure Leaching of Vanadium-bearing Converter Slag

Oxygen pressure leaching process was carried out to extract vanadium from converter slag of Panzhihua steelmaking plant of China. The kinetics of oxygen pressure leaching was described using the Shrinking Core Model (SCM) for the reaction between liquid and solid. The effects of particle size, temperature, initial acid concentration and stirring speed on the leaching rate of vanadium were investigated. The leachate and the residue were characterized by ICP, XRD and XRF. The experiment results show that temperature, initial acid concentration and stirring speed have significant effects on the leaching rate of vanadium, but particle size not. It indicates that the kinetics of leaching is controlled by external diffusion process of SCM, activation energy (Ea) is 11.84 KJ.mol(-1), and the reaction order (n) is 0.92133. The kinetic equations influenced by temperature, initial acid concentration and stirring speed are Igk=-0.61839x103/T-0.64215, Ink=0.92133InC(0)-9.95326 and Ink=0.30459InR-7.09105 respectively.