METHOD OF PROCESSING DEPLETED VANADIUM CATALYST OF SULFURIC ACID PRODUCTION Russian patent published in 1995 - IPC

FIELD: chemical technology. SUBSTANCE: processing is carried out by treatment of catalyst with alkaline solution (concentration is 30-100 g/l) at 30-100 C at separation of V-containing liquid from slime. Before extraction 0.35-3% H₃PO₄ (as P₂O₅ of depleted catalyst mass) is added to V-containing liquid following by neutralization of liquid and its separation from precipitate. Vanadium extraction is carried out with quaternary base salt obtaining raffinate and extract. Raffinate is evaporated up to potassium and sodium sulfates isolation, and extract is reextracted, and V₂O₅ is isolated. As a result of alkaline treatment of catalyst V and Al were converted to the solution. Their extraction are 80-95% and 60-95% and that of potassium and sulfur - 90-95% of content in parental catalyst. Trialkylbenzylammonium chloride or sulfate is used as an extractant. Treatment with alkaline solution is carried out mainly at potassium oxide concentration in it by sodium oxide sum - 40-100 mol.%. EFFECT: increased extraction degree of catalyst usable substances - vanadium, potassium, sulfur, aluminium. 2 cl, 2 tbl