Optimization and dissolution kinetics of vanadium recovery from LD converter slag in alkaline media

Resumo

Alkaline roasting-alkaline leaching process was used to recover vanadium from LD (Linz Donawitz) converter slag. The independent leaching parameters investigated were liquid to solid ratio (L/S) (10–20 mL/g), temperature (40–60°C), NaOH concentration (1.0–3.0 M), and time (60–120 minutes). Response surface methodology (RSM) was utilized to optimize the leaching parameters and as a result, the most influencing parameter was found to be liquid to solid ratio. Based on the results, the optimum recovery condition (approx. 99%) was obtained with L/S ratio of 20, temperature of 40°C, NaOH concentration of 3.0M, and leaching time of 100 minutes, respectively. Furthermore, the kinetics of alkaline leaching process was investigated using shrinking core model (SCM) equations. It was found that the rate of vanadium leaching is controlled by a mixed controlling mechanism which is comprised of chemical reaction and diffusion through the solid product layer.