Hao Peng
Yangtze Normal University, China
Title: A green method to leach vanadium and chromium from residue using NaOH-H2O2
Biography
Biography: Hao Peng
Abstract
Hydrogen peroxide as an oxidant was applied in leaching of vanadium and chromium in concentrated NaOH solution. To obtain the optimal reaction conditions, the effects of various reaction parameters were systematically investigated. The leaching efficiency of vanadium was found to exhibited an analogously parabolic characteristic with the increase in reaction temperature; in addition, the increase in the mass ratio of NaOH-to-residue, the volume ratio of H2O2-to-residue, reaction time favored the leaching process, with the optimal reaction condition determined as the liquid to solid ratio of 4.0 ml/g, residue particle size of < 200 mesh, the mass ratio of NaOH-to-residue of 1.0 g/g, the volume ratio of H2O2-to-residue of 1.2 ml/g, reaction temperature of 90 °C and reaction time of 120 min. Under the optimal reaction conditions, the leaching efficiency of vanadium and chromium could reach up to 98.60% and 86.49%, respectively. Compared with the current liquid-phase oxidation technologies, the reaction temperature was 90-310 °C lower, and the NaOH concentration of the reaction medium is lower by more than 50 wt% (the mass ratio of NaOH-to-residue of 1.0 g/g equals to concentration of 20 wt%). The kinetics study revealed that leaching process of chromium and vanadium were interpreted with shrinking core model under chemical reaction control. The apparent activation energy of chromium and vanadium dissolution was 22.19 kJ/mol and 6.95 kJ/mol, respectively.