Highly efficient oxidative-alkaline-leaching process of vanadium-chromium reducing residue and parameters optimization by response surface methodology

ABSTRACT

Vanadium-chromium reducing residue was not only a typical solid waste in the steel industry but also a valuable secondary source for recovery of vanadium and chromium. A highly efficient oxidative-alkaline-leaching technology with Na₂S₂O₈ was applied in this work. The effect of experimental factors including m(NaOH)/m(Residue), liquid-to-solid ratio, reaction temperature, m(Na₂S₂O₈)/m(Residue) and reaction time, on the leaching process were investigated. It was showed that 96.3% vanadium was leached out under selected conditions: m(NaOH)/m(Residue) = 0.30, liquid-to-solid ratio of 5 mL/g, reaction time of 60 min, m(Na₂S₂O₈)/m(Residue) = 0.50, reaction temperature of 90°C and stirring rate at 500 rpm, respectively. The leaching kinetics behaviour analysis demonstrated that the controlling step of the reaction was the diffusion of residue through the liquid film, and the Ea for vanadium leaching out was calculated to 15.57 kJ/mol. Response surface methodology was applied to analyze the interaction of the main conditions and the results showed that the influence of experimental factors on the leaching efficiency of vanadium followed the order: m(NaOH)/m(Residue) (B) > m(Na₂S₂O₈)/m(Residue) (C) > reaction temperature (E) > reaction time (D) > liquid-to-solid ratio (A).

GRAPHICAL ABSTRACT

KEYWORDS:

• Oxidative-alkaline-leaching
• response surface methodology
• vanadium

Acknowledgment

This work was supported by the Science and Technology Research Program of Chongqing Municipal Education Commission (No. KJQN201901403), Chongqing Science and Technology Commission (No. cstc2018jcyjAX0018) and the National Natural Science Foundation of China (No. 51804062).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Chongqing Municipal Education Commission: [Grant Number KJQN201901403]; Chongqing Science and Technology Commission: [Grant Number cstc2018jcyjAX0018]; National Natural Science Foundation of China: [Grant Number No. 51804062].