An insight on the mechanism of efficient leaching of vanadium from vanadium shale induced by microwave-generated hot spots

• Published in: International journal of minerals, metallurgy and materials Vol. 30; no. 2; pp. 293 - 302
• Main Authors: Li, Sheng, Zhang, Yimin, Yuan, Yizhong, Hu, Pengcheng
• Format: Journal Article
• Language: English
• Published: Beijing University of Science and Technology Beijing 01.02.2023; Springer Nature B.V; Collaborative Innovation Center of Strategic Vanadium Resources Utilization,Wuhan 430081,China; School of Resource and Environmental Engineering,Wuhan University of Science and Technology,Wuhan 430081,China; State Environmental Protection Key Laboratory of Mineral Metallurgical Resources Utilization and Pollution Control,Wuhan University of Science and Techno-logy,Wuhan 430081,China; Hubei Provincial Engineering Technology Research Center of High Efficient Cleaning Utilization for Shale Vanadium Resource,Wuhan University of Science and Technology,Wuhan 430081,China%School of Resource and Environmental Engineering,Wuhan University of Science and Technology,Wuhan 430081,China; Hubei Provincial Engineering Technology Research Center of High Efficient Cleaning Utilization for Shale Vanadium Resource,Wuhan University of Science and Technology,Wuhan 430081,China; School of Resource and Environmental Engineering,Wuhan University of Technology,Wuhan 430070,China
• Subjects: Calcium fluoride; Ceramics; Characterization and Evaluation of Materials; Chemistry and Materials Science; Composites; Corrosion and Coatings; Dosage; Electric contacts; Electric fields; Glass; Heating; High temperature; Leaching; Materials Science; Metallic Materials; Mica; Microwave heating; Natural Materials; Recovery; Shales; Sulfuric acid; Surfaces and Interfaces; Thin Films; Tribology; Vanadium; vanadium shale; hot spots; numerical simulation; microwave-assisted leaching
• ISSN: 1674-4799; 1869-103X
• DOI: 10.1007/s12613-022-2459-7

Microwave heating can rapidly and uniformly raise 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. The effects of the microwave power, leaching temperature, CaF 2 dosage, H 2 SO 4 concentration, and leaching time on the vanadium recovery were investigated. A vanadium recovery of 80.66% is obtained at a microwave power of 550 W, leaching temperature of 95°C, CaF 2 dosage of 5wt%, H 2 SO 4 concentration of 20vol%, and leaching time of 2.5 h. Compared with conventional leaching technology, the vanadium recovery increases by 6.18%, and the leaching time shortens by 79.17%. More obvious pulverization of shale particles and delamination of mica minerals happen in the microwave-assisted leaching process. Numerical simulation results show that the temperature of vanadium shales increases with an increase in electric field (E-field). The distributions of E-field and temperature among vanadium shale particles are relatively uniform, except for the higher content at the contact position of the particles. The analysis results of scale-up experiments and leaching experiments indicate high-temperature hot spots in the process of microwave-assisted leaching, and the local high temperature destroys the mineral structure and accelerates the reaction rate.