An Alternative Technology for Ilmenite Processing

Conventional processing of ilmenites into titania pigment or titanium metal involves upgrading of ilmenite concentrates to synthetic rutile or titania-rich slag followed by high temperature carbochlorination to form titanium tetrachloride. In an alternative technology, titanium oxides are reduced to titanium oxycarbide or titanium oxycarbonitride, which are chlorinated at a much lower temperature. Ilmenites were reduced using a methane-hydrogen-argon gas mixture or graphite. The reducing CH4-H-2-Ar gas provided high carbon activity which made reduction/carburisation reaction fast and feasible at lower temperature. Methane was also involved in the low-temperature carbothermal reduction of ilmenites in hydrogen in production of titanium oxycarbide or in hydrogen-nitrogen gas in synthesis of titanium oxycarbonitride. Both compounds were chlorinated at 235 degrees C. Extent of chlorination of titanium oxycarbide and oxycarbonitride after iron removal was close to 100% after 30 min of reaction.