Method for producing trivalent vanadium sulfate and method for producing vanadium electrolyte

摘要

PROBLEM TO BE SOLVED: To provide a manufacturing method for a trivalent vanadium compound at a low cost capable of manufacturing only trivalent vanadium sulfate from a vanadium compound having a tetravalent or pentavalent vanadium compound as a principal component at a stretch by only using a reducer, and a manufacturing method for a redox flow type vanadium-based electrolyte. SOLUTION: This manufacturing method comprises kneading a vanadium compound having a pentavalent vanadium compound as a principal component, sulfur =0.5 mol times based on 1 mol of a vanadium atom in the pentavalent vanadium compound, and concentrated sulfuric acid 1.5-2.3 mol times based on the same, until a mixture becomes paste-like, and then heating the paste-like mixture to 150-440 deg.C to obtain a trivalent vanadium compound. After that, the trivalent vanadium compound is dissolved in sulfuric acid or a sulfuric acid aqueous solution to obtain a redox flow type electrolyte.