Process for solubilizing vanadium and optionally for obtaining ammonium metavanadate or v o

摘要

Vanadium as alkali metal vanadate is recovered from vanadium bearing materials comprising slags, ores and residues by oxidizing a melt of the material, an alkali metal carbonate and an alkali metal chloride having weight ratio 1 : 1 : 0.5 to 1 : 0.5 : 1 respectively, with air or oxygen at above 400 DEG C., say between 600 DEG and 700 DEG C., and extracting alkali metal vanadate with, say, water. The oxidizing agent may be air, oxygen, or solid oxidant such as a chlorate, nitrate or peroxide. The melting can be effected by direct or indirect heating. Silica may be added to the material to be reacted. One part slag is crushed, mixed with 1 part sodium carbonate and 0.5 part sodium chloride, and melted in a rotary furnace by an oxidizing flame. Air is blown over the melt at 650 DEG C. for 30 minutes, and sodium vanadate extracted by stirring the melt in water at 80 DEG to 90 DEG C. in an iron vessel. The sodium vanadate solution may be adjusted to pH 3 to 7 e.g. 6.5, with a mineral acid and ammonium metavanadate precipitated by adding the ammonium salt of the acid employed at 80 DEG to 90 DEG C., maintaining said temperature for 1 hour before cooling. The salt may be separated, washed with cold water, the washings being returned to the iron dissolving vessel, dried and decomposed at above 300 DEG C., e.g. 450 DEG C., to powdered or at 700 DEG C. to molten vanadium pentoxide.