Selective separation method of vanadium-chromium based on quaternary ammonium N263

• 1、School of Metallurgy and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083

Abstract：Due to the similar chemical properties of vanadium and chromium, the separation of vanadium and chromium in vanadium-chromium leachate has become a difficulty. The raw material used in this paper is the oxalic acid leachate containing vanadium and chromium. Based on the characteristics of the raw material, the vanadium and chromium elements in the solution are first enriched by the hydrothermal precipitation method. The enrichment and precipitation rates of vanadium and chromium elements reach 98.80% and 97.45% respectively. Then, the vanadium-chromium-rich group was transferred to the sulfuric acid system, and the vanadium-chromium-containing acid leaching solution was obtained under the optimal conditions of acid leaching temperature of 100℃, 35% sulfuric acid concentration, and liquid-solid ratio of 6:1mL/g. Subsequently, hydrogen peroxide was used to selectively oxidize vanadium in the solution and convert it into anions. Subsequently, the N263 extractant was selected to extract the acid leaching solution. Under the single-stage extraction conditions with a ratio of 4:1 and an extraction time of 8 minutes, an organic phase with a vanadium loading of 2.187 g/L and a chromium residue of only 0.004g/L was obtained, and the number of vanadium-chromium separation systems reached 627. Subsequently, the loaded organic phase achieved efficient stripping of vanadium under the mixed acid stripping agent of sulfuric acid and oxalic acid. The concentration of V in the stripping solution was 9.693g/L and the concentration of Cr was only 0.003g/L, achieving deep separation of vanadium and chromium.

Keywords： Vanadium-chromium separation Solvent extraction N263 extractant Hydrothermal decomposition