METHOD OF PROCESSING OF TECHNICAL-GRADE VANADIUM PENTOXIDE Russian patent published in 2003 - IPC

FIELD: metallurgy; applicable, particularly, at works of ferrous and nonferrous metallurgy for production of vanadium pentoxide from technical-grade pentoxide containing 50- 95% of V₂O₅ and impurities in form of oxides of Fe, Cr, Mn, Al, Si, Mg, Cu and others. SUBSTANCE: method includes treatment of technical-grade vanadium pentoxide with solution of sodium hydroxide, separation of insoluble residue of metal-impurities hydroxides from solution of sodium metavanadate NaVO₃, introduction into solution of ammonium-containing inorganic compounds, precipitation and crystallization of NH₄VO₃, filtration of suspension, separation of mother liquor from sediment NH₄VO₃, sediment washing, its drying and calcination to produce commercial vanadium pentoxide. Novelty in offered method is the fact that treatment with solution of sodium hydroxide is carried out with NaOH concentration of 40-120 g/cu. dm. insoluble residue after separation from solution of sodium metavanadate is treated at 90-100C with solution of sodium hypochlorite with concentration of 30-90 g/cu.dm taken in amount of 2-4 cu.dm per Kg of insoluble residue for 3-4 h with mixing. Then, introduced into pulp is sodium sulfur-containing salt selected from series including: Na₂S, NaHS, Na₂SO₃, Na₂S₂O₃. Residue is separated from solution which is combined with solution of NaVO₃ formed at stage of treatment of technical-grade vanadium pentoxide with solution of sodium hydroxide. Said treatment of technical-grade vanadium pentoxide is carried out at Liquid:solid=4-8 for 0.5-2 h at 60-90C. It is sound practice, to introduce sodium sulfur-containing salt in amount of 5-20 g/cu.dm in form of solution with concentration of 50-150 g/cu.dm. EFFECT: higher degree of vanadium recovery into product. 3 cl, 3 ex