ISSN: 1003-6326
CN: 43-1239/TG

Vol. 32    No. 4    April 2022

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φ-pH diagrams and kinetics of V2O3 prepared by solution-phase hydrogen reduction
Yi-bo HU1,2,3,4, Yi-min ZHANG1,2,3,4, Nan-nan XUE1,2,3,4, Peng-cheng HU1,2,3,4, Liu-hong ZHANG1,2,3,4
(1. College of Resources and Environmental Engineering, Wuhan University of Science and Technology, Wuhan 430081, China;
2. State Environmental Protection Key Laboratory of Mineral Metallurgical Resources Utilization and Pollution Control, Wuhan University of Science and Technology, Wuhan 430081, China;
3. Hubei Collaborative Innovation Center for High Efficient Utilization of Vanadium Resources, Wuhan 430081, China;
4. Hubei Provincial Engineering Technology Research Center of High Efficient Cleaning Utilization for Shale Vanadium Resource, Wuhan University of Science and Technology, Wuhan 430081, China
Abstract: Solution-phase hydrogen reduction (SpHR) was introduced into V2O3 preparation to overcome disadvantages of traditional reduction roasting, which include a long process, high energy consumption, and generation of pollution. The research mainly focuses on φ-pH diagrams and kinetics of SpHR. Thermodynamic analysis of φ-pH diagrams for the V-H2O system demonstrates that V2O3 preparation via SpHR requires a high temperature, a high vanadium concentration, and sufficient hydrogen in acidic solution. Kinetic analyses show that the activation energy of V2O3 preparation via SpHR is 38.0679 kJ/mol, indicating that the reduction is controlled by a combination of interfacial chemical reaction and internal diffusion. Effects of H2 partial pressure (slope K=0.05246) on the reaction rate is not as significant as the vanadium concentration (K=1.58872). V2O3 crystals with a purity of 99.59% and a vanadium precipitation rate of 99.83% were obtained under the following conditions: pH=5-6, c(V2O5)=0.5 mol/L, p(H2)=4 MPa, m(PdCl2)=10 mg, T=250 °C, and t=2.5 h.
Key words: V2O3; solution-phase hydrogen reduction; φ-pH diagram; kinetics
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