Multistage utilization process for the gradient-recovery of V, Fe, and Ti from vanadium-bearing converter slag.

A multistage utilization process was developed to fully recover valuable metals from vanadium-bearing converter slag and reduce the content of hazardous elements, such as vanadium and chromium, in the tailings. A mechanical activation-calcification roasting-acid leaching process was firstly employed to recover vanadium. This process generated two products, viz. a V-bearing solution accounting for ∼95% V recovery and vanadium tailings with Fe and Ti contents of 31.85% and 8.94%, respectively. Then, based on theoretical calculations and physical measurements, a coal-based direct reduction-magnetic separation process and a hydrochloric acid leaching process were employed for the stepwise recovery of iron and titanium, respectively, from the vanadium tailings. Iron was recovered in the form of high chromium-vanadium iron with 81.53% Fe, 1.31% Cr, and 2.04% V, and titanium was recovered as titanium dioxide pigment with 85-90% yield. Such a comprehensive and clean utilization of vanadium-bearing converter slag has great potential for practical application.