High Purity Titania Powder can be prepared through the following methods.
1. Sulphate Process
2. Chloride Process
3. Alkoxide Process
4. Forced Hydrolysis Process
5. Laser Synthesis Process
Sulphate Process
The natural occuring ilmenite ore is first processed into usable form by the mineral processing route. The purified and processed ore is digested with sulphuric acid in a digester under stirring conditions. The digester temperature is maintained between 150oC to 200oC. During digestion the sulphuric acid reacts with ilmenite (FeTiO3) and the sulphates of Titania and Iron are formed during reaction. The crystallized FeSO47H2O is separated. The titania remains in the solution form as Titanyl Sulphate. The hydrous Titania (TiO2) containing the SO3 group is prepared by the hydrolysis of the titanyl sulphate solution followed by heating. The hydrous form TiO2 is obtained as flocculates of small anatase crystals with particle size of between 0.04-0.5 micron. The further heating of these crystals between 150oC to 650oC else to expel out the water and SO3 followed by the particle growth. The transformation of Rutile from anatase takes place in the temperature range of 700oC -950oC . Most of the commercial applications TiO2 is prepared by this method.
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