Mechanisms and kinetics of a new cleaner single cyclic roasting-leaching process for the extraction of vanadium from Linz–Donawitz converter slag using CaCO3 and H2SO4

Prevailing alternative technologies of vanadium extraction from vanadium slag that suffer from high production costs, energy consumption and serious environmental pollution due to the large production of toxic solid-liquid-gaseous effluents are that non-environmental-friendly. This study implemented a new, cleaner, more effective and environmentally-friendly method of the single cyclic roasting-acid leaching, where vanadium clinker, residue and liquor can be recycled as roasting additive and leaching agent to enhance the roasting-leaching effect. The complete single cyclic roasting-acid leaching process of the chemicals, mechanisms and the maximum roasting conversion efficiency achieved in the case of vanadium is 88.86%–92.39% and leaching efficiency of 93.77%–97.61%. Herein, the recycling and reuse of all the liquor and leaching residue result in the zero-liquid discharge, solid waste reduction, significant cleanliness, and high resource utilization. This work has opened a new pathway of establishing a significantly cleaner production process for environmental sustainability via design and incorporation of inner recycling of wastes into the process in which these wastes are produced. In addition, the thermodynamics and kinetics of the whole single cyclic roasting-acid leaching process analysis can help us understand the mechanisms. All results and conclusions have guiding significance to industrial production of V2O5 from vanadium slag.