The kinetics of oxidative leaching of vanadium trioxide

• Published in: Hydrometallurgy 2014-08, Vol.147-148, p.83-89
• Main Authors: Tavakoli, M.R., Dreisinger, D.B.
• Format: Article
• Language: English
• Subjects: Activation energy; Constants; Ferric ions; Ferric-ferrous ratio; Hydrometallurgy; Kinetics; Leaching; Oxidative leaching; Potassium permanganate; Potential control; Vanadium; Vanadium trioxide
• ISSN: 0304-386X; 1879-1158
• DOI: 10.1016/j.hydromet.2014.04.020

The oxidative leaching of vanadium trioxide was studied in sulfuric acid solutions from 30°C to 90°C. This study was performed in three stages. First, the kinetics of leaching using oxygen was investigated. It was shown that this oxidative leaching is chemically-controlled with an activation energy of around 69kJ/mol. Secondly, vanadium(III) oxidative leaching was studied using ferric ions and oxygen. The presence of ferric enhanced kinetics significantly. Finally, oxidative leaching using a constant ferric–ferrous ratio from 1 to 300 was investigated. Potassium permanganate (KMnO4) was found to be a suitable oxidant for controlling solution potential. The oxidation rate using a constant ferric–ferrous ratio was very sensitive to temperature, giving a large activation energy (38kJ/mol) and was proportional to the Fe(III)/Fe(II) ratio to the power of 0.47. The leaching rate using the shrinking sphere model was modeled as:∂d∂t=12,088×exp−4580TCFeIIICFeII0.47μmmin. •Oxidative leaching of vanadium(III) is studied using oxygen and Fe(III)/Fe(II).•Atmospheric oxidative leaching of vanadium(III) using oxygen is slow.•Fe(III) can increase kinetics of vanadium(III) leaching significantly.•The oxidation rate was proportional to the Fe(III)/Fe(II) to the power of 0.47.