Efficient recovery of vanadium from calcification roasted-acid leaching tailings enhanced by ultrasound in H2SO4-H2O2 system

Abstract

Residual vanadium accounts for about 1% of calcification roasted-acid leaching tailings after industrial vanadium extraction. Vanadium pollution is primarily induced by the stacking of tailings. In this study, the conventional leaching process based on sulfuric acid is compared with the ultrasound-H2O2 synergistic enhanced process in the extraction of residual vanadium from calcification roasted-acid leaching tailings. Besides, the experimental process parameters are also optimized. Under the optimal conditions, the vanadium leaching rate increases by 63.64%, and the energy consumption decreases by 50%. The experimental enhancement mechanism is clarified by exploring the decomposition patterns of H2O2 under ultrasound in combination with the characterization results based on electron paramagnetic resonance (EPR). Under the action of ultrasound, H2O2 is effectively decomposed into •OH radicals to provide higher oxidation potential, which accelerates the reaction process. Through the characterization and analysis of the samples before and after the experiment, it is found that H2O2 enhances the cavitation effect of ultrasound. This effectively destroys the composite oxide structure on the surface of tailing particles, thus increasing the reaction area. In conclusion, the ultrasound-H2O2 synergistic vanadium leaching process exhibits broad application prospects in the management and recovery of industrial tailings.