Promoting the Calcified Roasting of Vanadium Slag Based on the CeO 2 -Catalytic Oxidation Mechanism.

Calcification roasting-acid leaching is a clean, efficient, and environmentally friendly process, but in the roasting process, the local temperature is often too high, the heat release is not timely, and the heat transfer is blocked. Furthermore, the material is easy to sinter, which affects the final vanadium extraction effect. In this paper, a small amount of CeO 2 was introduced in the roasting process of vanadium slag to promote the calcified roasting. The results showed that the vanadium leaching rate reached 93.17% with the addition of 0.1 wt % CeO 2 at a roasting temperature of 750 °C, which was higher than that obtained without CeO 2 addition (90.00%). The results of XPS, XRD, and SEM-EDS analyses confirmed that adding CeO 2 to the roasted clinker significantly increased the proportion of pentavalent vanadium to the total vanadium by up to 28.64%. O 2 -TPD analysis revealed an enhanced chemisorbed oxygen with the CeO 2 -assisted roasting, indicated the activation of oxygen by CeO 2 , and resulted in an enhanced oxidation of vanadium. The work in this paper establishes an alternative route for catalytic oxidation-enhanced vanadium slag roasting, which can improve the utilization of vanadium slag at relatively lower temperatures under the action of CeO 2 and is of positive significance in solving the problems of sintering and energy consumption in the roasting process.