METHOD OF PROCESSING EXHAUSTED VANADIUM CATALYST Russian patent published in 1998 - IPC

FIELD: inorganic synthesis catalysts. SUBSTANCE: invention relates to hydrochemical methods for reusing vanadium catalyst wastes from contact sulfuric acid production involving ferrous and nonferrous metallurgy gases. Method includes treating vanadium catalyst with alkaline component at elevated temperature, filtering pulp to separate silica precipitate, adding mineral acid, subsequent treatment and calcination (400-600 C) of vanadium-containing component. According to invention, mineral acid is added in amount high enough to obtain pH 7-8.5 and resulting vanadium component is processed via filtering off impurities and washing precipitate. Vanadium-containing filtrate is combined with wash water, combined solution is partially evaporated to separate potassium sulfate crystals and thereafter sulfuric acid is added in amount 0.3 to 0.67 g-ion of H⁺ per 1 g-ion of vanadium trioxide to precipitate decavanadate , which is separated and treated with stoichiometric amount of vanadium salt to form ammonium polyvanadate. EFFECT: improved quality of product, simplified procedure, and excluded necessity for utilizing mother solution after separation of vanadate. 2 cl, 1 tbl