METHOD OF PROCESSING VANADIUM-CONTAINING MIDDLINGS Russian patent published in 2001 - IPC

FIELD: metallurgy; production of commercial vanadium pentoxide from various middlings. SUBSTANCE: method includes treatment of vanadium-containing middlings with alkaline solution, separation of insoluble residue from NaVO₃ solution and washing it, combining filtrate and alkaline industrial water, introducing ammonium-containing inorganic compound, for example NH₄Cl and/or NH₄NO₃,, separation of ammonium metavanadate from solution and its crystallization, filtration of suspension, separation of NH₄VO₃ sediment from mother liquor, flushing, drying and calcinating the sediment, thus obtaining commercial vanadium pentoxide. NaOH solution at concentration of 40120 g/cu.dm is used as alkaline reagent; sodium hypochlorite is preliminarily introduced into alkaline reagent to obtain concentration of NaClO from 5 to 25 g/cu.dm and treatment is conducted at mole ratio of NaOH:NaClO = 1: (0.05-0.2) at L:S =(8- 12):1 for 0.5-2 h at 60-90 C. EFFECT: increased extraction of vanadium. 3 ex