Comparison of the mechanisms of microwave roasting and conventional roasting and of their effects on vanadium extraction from stone coal

• Published in: International journal of minerals, metallurgy and materials Vol. 22; no. 5; pp. 476 - 482
• Main Authors: Yuan, Yi-zhong, Zhang, Yi-min, Liu, Tao, Chen, Tie-jun
• Format: Journal Article
• Language: English
• Published: Beijing University of Science and Technology Beijing 01.05.2015; Springer Nature B.V; Hubei Provincial Engineering Technology Research Center of High efficient Cleaning Utilization for Shale Vanadium Resource, Wuhan 430081, China; College of Resources and Environmental Engineering, Wuhan University of Science and Technology, Wuhan 430081, China
• Subjects: Ceramics; Characterization and Evaluation of Materials; Chemistry and Materials Science; Coal; Composites; Corrosion and Coatings; Extraction; Fourier transforms; Glass; Infrared analysis; Irradiation; Leaching; Low temperature; Materials Science; Metallic Materials; Mica; Microwaves; Muscovite; Natural Materials; Roasting; Stone; Sulfuric acid; Surfaces and Interfaces; Thin Films; Tribology; Vanadium; X-ray diffraction; 微波照射; 扫描电子显微镜; 提钒; 机制; 浸出时间; 焙烧温度; 煤比; 硫酸浓度; vanadium metallurgy; stone coal; leaching; extraction; vanadium oxides; microwave roasting
• ISSN: 1674-4799; 1869-103X
• DOI: 10.1007/s12613-015-1096-9

Experiments comparing microwave blank roasting and conventional blank roasting for typical vanadium-bearing stone coal from Hubei Province in central China, in which vanadium is present in muscovite, were conducted to investigate the effects of roasting tempera- ture, roasting time, H2SO4 concentration, and leaching time on vanadium extraction. The results show that the vanadium leaching efficiency is 84% when the sample is roasted at 800℃ for 30 min by microwave irradiation and the H2SO4 concentration, liquid/solid ratio, leaching temperature, and leaching time are set as 20vo1%, 1.5：1 mL.g-1, 95℃, and 8 h, respectively. However, the vanadium leaching efficiency achieved for the sample subjected to conventional roasting at 900℃ for 60 min is just 71% under the same leaching conditions. Scanning electron microscopy （SEM） analysis shows that the microwave roasted samples contain more cracks and that the particles are more porous compared to the conventionally roasted samples. According to the results of X-ray diffraction （XRD） and Fourier-transform infrared （FTIR） analyses, neither of these roasting methods could completely destroy the mica lattice structure under the experimental conditions; however, both methods deformed the muscovite structure and facilitated the leaching process. Comparing with conventional roasting, microwave roasting causes a greater deformation of the mineral structure at a lower temperature for a shorter roasting time.