METHOD FOR PRODUCTION OF VANADIUM PENTAOXIDE FROM MAN-MADE RAW MATERIAL Russian patent published in 2001 - IPC

FIELD: metallurgy. SUBSTANCE: in a method, wherein starting vanadiumcontaining waste, slag, and/or production middlings are treated with alkaline reagent, vanadium is selectively taken out from solid phase into solution, sodium metavanadate solution is separated from insoluble precipitate, inorganic ammonium salt is added to solution, resulting ammonium metavanadate is crystallized, precipitated, filtered off and calcined to give commercial vanadium pentaoxide, after treatment with alkaline solution and separation of solution from precipitate, the latter is additionally treated with mineral acid solution, pulp is filtered, alkaline and acidic solutions combined, refiltered, divided into two parts, of which one part is supplemented by alkaline reagent and the other by mineral acid. Alkaline and acidic solutions are further reused for treatment of precipitate and are recycled until vanadium concentration in combined solution arrives at a value within a range of 15 to 100 g/cu.dm. More particularly, consecutive treatment of vanadium-containing raw material is carried out with sodium hydroxide solution and hydrochloric acid solution at their concentrations between 20 and 120 g/cu.dm and temperature 80-90 C, liquid-to-solids ratio varying between 4 and 8 and solid-to-liquid phase contact time between 0.5 and 1 h. Combination of vanadium-containing alkaline and acidic solutions is carried out under mutual neutralization conditions until final pH value of combined solution (pulp) reaches 5-9. EFFECT: increased vanadium recovery degree. 3 cl, 2 ex