|Cite this article as:|
|Sheng Li, Yimin Zhang, Yizhong Yuan, and Pengcheng Hu, A novel insight on the mechanism of efficient leaching of vanadium from vanadium shale induced by microwave-generated hot spots, Int. J. Miner. Metall. Mater.,(2022). https://doi.org/10.1007/s12613-022-2459-7|
Microwave heating can rapidly and uniformly rise the temperature and accelerate the reaction rate. In this paper, microwave heating was used to improve the acid leaching and the mechanism was investigated via microscopic morphology analysis and numerical simulation by COMSOL Multiphysics software. Effects of microwave power, leaching temperature, CaF2 dosage, H2SO4 concentration and leaching time on vanadium leaching recovery were investigated. A vanadium leaching recovery of 80.66% was obtained at a microwave power of 550 W, leaching temperature of 95°C, CaF2 dosage of 5wt.%, H2SO4 concentration of 20vol% and leaching time of 2.5 h. Compared with conventional leaching technology, vanadium leaching recovery increased by 6.18% and the leaching time shortened by 79.17%. More obvious pulverization of shale particles and delamination of mica minerals happened in the microwave-assisted leaching process. Numerical simulation results show that the temperature of vanadium shales increased with the electric field (E-field) intensity. The distribution of E-field and temperature among vanadium shales particles was relatively uniform, except for the higher content at the contact position of particles. The analysis results of scale-up experiments and leaching experiments indicated high-temperature hot spots in the process of microwave-assisted leaching, and the local high temperature destroyed the mineral structure and accelerated the reaction rate.