A green method to leach vanadium and chromium from residue using NaOH-H2O2

Abstract

Hydrogen peroxide as an oxidant was applied in leaching of vanadium and chromium in concentrated NaOH solution. Under the optimal reaction conditions (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), 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.

Highly Efficient Recovery of Vanadium and Chromium: Optimized by Response Surface Methodology

“…The increase of NaOH increased the reaction activity of the hydroxide ions and enabled the oxidation reactions to be thermodynamically more favorable. 21 It also intensified the oxidation solubility and mass transfer efficiency during the leaching process. eq 2 and the perturbation plot show that the reaction time and stirring rate exhibited parabola effects.…”

“…The leachate was obtained by vacuum filtration after a required time. The detailed processes can be seen in the refs 21, 22, 31 . The concentrations of vanadium and chromium in the filtrate were determined by inductively coupled plasma-optical emission spectrometry.…”

A Novel Technology for Recovery and Separation of Vanadium and Chromium from Vanadium-Chromium Reducing Residue

“…The VCRR was precipitated from wastewater containing vanadium and chromium(III) from an iron and steel mill from Pan Gang Group Co., Ltd., Panzhihua, Sichuan Province, China [8,21,22]. Before the experiment, the residue was first dried in an oven overnight, followed by dry-sieving to obtain particles through < 200 mesh, and then characterized by XRF (XRF-1800, Shimadzu, Japan, shown in Table 1).…”

“…To date, various hydrometallurgy technologies, such as direct NaOH leaching [5] and electric field alkaline leaching [6,7] have been developed to recover vanadium from the VCRR. The "NaOH-H 2 O 2 " combined direct leaching and roasting alkaline leaching are commonly used for VCRR processing [8][9][10]. However, the recovery of chromium was rarely focused.…”

Oxidative Leaching of Vanadium from Vanadium-Chromium Reducing Residue with MnO₂

“…All experiments were performed in a glass beaker with a thermostatic mixing water bath pot [11,17,18].…”