Kinetics of Vanadium Leaching from a Spent Industrial V2O5/TiO2 Catalyst by Sulfuric Acid

Recovery of vanadium from various sources is important to the environment and industry. This work investigates vanadium leaching from a spent selective catalytic reduction catalyst by sulfuric acid at atmospheric pressure. It includes the effects of stirring speed, solid to liquid ratio, temperature, and sulfuric acid concentration on the vanadium recovery yield. The results show that the vanadium recovery yield increases with increases in temperature, sulfuric acid concentration, and leaching time and decreases with an increase in solid to liquid ratio. The leaching data can not be described well by kinetic models commonly adopted for similar processes in the literature. The Avrami equation, originally developed for crystallization, is found to be most suitable. The leaching is controlled by diffusion in the solid with an activation energy of 5.90 kJ/mol.