Novel Technology for Vanadium and Chromium Extraction with KMnO4 in an Alkaline Medium

This paper focused on the oxidation-alkaline extraction process of vanadium-chromium-reducing residue. The affected parameters including reaction temperature, KMnO4 dosage, reaction time, NaOH dosage, and liquidto-solid ratio on the extraction process were investigated. The E-pH diagram and the thermodynamic analysis indicated that KMnO4 was suitable for the oxidation of low-valence vanadium and chromium. Vanadium (97.24%) and chromium (56.20%) were extracted under the following optimal reaction conditions: reaction temperature of 90 degrees C, reaction time of 90 min, dosage of KMnO4 at m(KMnO4)/m(residue) = 0.40, dosage of NaOH at m(NaOH)/m(residue) = 0.30, and liquid-to-solid ratio at 5:1 mL/g. The extraction process of vanadium was controlled by the reactant through the solid product layer and the extraction kinetics behavior fitted well with the shrink core model with an E-a of 15.37 kJ/mol. At the same time, the surface chemical reaction was the controlling step for chromium extraction, which was difficult with an E-a of 39.78 kJ/mol.

Automated summary

This paper focused on the oxidation-alkaline extraction process of vanadium-chromium-reducing residue, investigating optimal conditions for high extraction rates. The extraction process for vanadium was controlled by the reactant, while chromium extraction was difficult due to surface chemical reactions.