Kinetic study on the leaching of vanadium-bearing converter slag with dilute sulfuric acid

Abstract

Calcification roasting-sulfuric acid leaching process was used to extract vanadium from converter slag. The kinetics of the extraction process based on both unmilled and ball milled slags in dilute sulfuric acid solution (pH = 2.5 ± 0.2) were investigated. The results showed that the extraction of vanadium was a rapid process with particularly a considerable proportion of vanadium rapidly dissolved in the first 10 min. The kinetics analysis showed that the diffusion through product layer was rate-determining step in the course of the dissolution of vanadium. The linear relationship between the rate constant and the inverse square of the particle diameter also illustrated this phenomenon. Mechanical activation can significantly accelerate the vanadium leaching efficiency, and decrease the corresponding apparent activation energy from 9.94 to 7.63 kJ/mol.