Short flow and eco-friendly process for V2O3 preparation via hydrogen-catalyzed solution-phase method

Abstract

V2O3 is mainly used to prepare ferro-vanadium. The introduction of solution-phase hydrogen reduction (SpHR) can reduce energy consumption, shorten the process and decrease ammonia pollution. In order to improve the hydrogen activity, PdCl2, Ni powder, and anthraquinone were selected as catalysts. Under the optimum condition, the precipitation ratio of product catalyzed by Ni powder was similar to that catalyzed by PdCl2, which were 99.80 % and 99.74 %, respectively. The purity of products met the requirements of GB 40301–2021, and the particle size of product catalyzed by Ni powder was more uniform. The products of SpHR with anthraquinone and auto-catalysis were Na(V2O5) and VO2(H2O)0.5, respectively. The activation energy of reaction catalyzed by PdCl2 and Ni powder were 38.0679 kJ/mol and 140.0909 kJ/mol, respectively. In the process of hydrogen-catalyzed, H2 molecule adsorbs on the surface of Ni or Pd, and form two Me-H bonds with strong reducibility, and its s orbital is hybridized with the d orbital of Pd and Ni. PdCl2 and Ni powder reduced the hydrogen dissociation energy from 434 kJ/mol to 30.3960 kJ/mol and 63.8332 kJ/mol, respectively. The phase transformation of vanadium precipitation by SpHR with the intervention of Ni catalyst is: HV10O285- or V(V) amorphous precipitation → filamentous Na2V6O16·3H2O → irregular flake Na(V2O5) → flaky VO2(H2O)0.5 → cross-like VO2(H2O)0.5 → rhombohedral V2O3.