Method for the preparation of desulfurized titanium oxide hydrolysate of high purity
OwnerEarl R. Lawhorne, Woodford R. Brown, Jr.inventors
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Abstract
A titanium oxide hydrolysate slurry prepared by the sulfate process is treated with either an alkali metal hydroxide or an alkali metal carbonate to solubilize the sulfur bound to the titanium at a temperature of from 60.degree. C. to 120.degree. C. and the slurry is treated with an organic acid to remove the alkali metal compounds present. This process produces titanium oxide hydrolysate of high purity.
Claims19
A method for the purification of titanium oxide hydrolysate containing bound sulfur impurities, which comprises:
- (1) mixing a compound selected from the group consisting of an alkali metal hydroxide and alkali metal carbonate with an aqueous slurry of said hydrolysate in an amount from about 0.1 to 2 parts by weight of the alkali metal hydroxide per part by weight of the TiO.sub.2 equivalent or at the molecular equivalent of an alkali metal carbonate in said hydrolysate while maintaining the temperature of the slurry between 60.degree. C. and 120.degree. C.;
- (2) filtering and water-washing said alkali-treated hydrolysate slurry thereby removing the alkali-solubilized impurities, including sulfur containing compounds and excess alkali metal hydroxide;
- (3) mixing a water soluble organic acid with the slurry to reduce the pH to less than about 6;
- and
- (4) filtering and water-washing said acid treated slurry thereby removing the acid solubilized impurities including alkali metal containing impurities.
A method for the purification of a titanium oxide hydrolysate containing bound sulfur impurities, which comprises:
- (1) mixing a compound selected from the group consisting of an alkali metal hydroxide and an alkali metal carbonate with an aqueous slurry of said hydrolysate in an amount from about 0.1 to 2 parts by weight of alkali metal hydroxide per part by weight of the TiO.sub.2 equivalent or the molecular equivalent of an alkali metal carbonate in said hydrolysate while maintaining the temperature of the slurry for a time which is sufficient to solubilize substantially all of the bound sulfur impurities;
- (2) filtering and water-washing the alkali-treated hydrolysate slurry thereby removing substantially the alkali-solubilized impurities, including sulfur containing compounds and excess alkali metal hydroxide;
- (3) mixing a non-chlorine containing water soluble organic acid with the slurry to reduce the pH to a sufficient acidic level to solubilize the alkali metal containing impurities;
- and
- (4) filtering and water-washing said acid treated slurry thereby substantially removing the acid solubilized impurities including alkali metal containing impurities.
Dependencies are inferred from the claim text.