Alkali Treatment of the Hydrous Titanium Oxide Obtained from Ilmenite Treated with Sulfuric Acid

Abstract

Hydrous titanium oxide obtained from ilmenite treated with sulfuric acid was suspended in a 3-5.8 mol// NaOH solution, which was then heated for 4 hr either at boiling point (104 to 110°C) under atmospheric pressure or 150°C in an autoclave. The resulting solution was diluted with water, solid matter remained being filtered off. The solubility of the cake thus obtained in dilute sulfuric acid increased with increasing concentration of sodium hydroxide, more than 90% of the cake being dissolved in the acid when the alkali concentration exceeded 5 mol/l. Results of chemical and X-ray analysis of the cakes revealed that Na₂Ti₄o₉, Na₂Ti₅o₁₁and Na₂Ti₆O₁₃ are formed by the alkali treatment of the hydrous titanium oxide.