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US 6,444,189 B1Granted
Process for making and using titanium oxide particles
AssigneeE. I. Du Pont de Nemours and Company
InventorsYing Wang, Donald Keith Swanson
Life of this patent
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Abstract
Titanium oxide particles are prepared from the reaction of an aqueous basic solution with (1) an aqueous acidic titanium salt solution, or (2) an aqueous salt solution of a titanium salt and an aqueous salt solution of a dopant metal salt. In preferred embodiments, the particles may range in size from 0.1 to 10 microns (10-6 meters), and possess relatively high bulk density combined with high surface area.
Claims9
A process for preparing titanium oxide particles, said process comprising:
- (a) preparing an aqueous acidic titanium salt solution of from about 10% to about 50% total titanium salt,
- (b) precipitating the titanium oxide particles by adding the acidic titanium salt solution to an aqueous basic solution containing at least 20% base while maintaining the temperature at from about 20° C. to about 95° C., after initial heating of reaction and dilution, until a pH of from about 2 to about 4 is reached.
A process for preparing doped titanium oxide particles with at least one other metal, said process comprising:
- (a) preparing an aqueous salt solution of a titanium salt and an aqueous salt solution of a dopant metal salt,
- (b) adding a major portion of the aqueous titanium salt solution to an aqueous basic solution containing at least 20% base while maintaining the temperature at from about 50° C. to about 95° C. after initial heating of reaction and dilution, to yield a first mixture,
- (c) combining the remaining titanium salt solution with the dopant metal salt solution to yield a second mixture, and
- (d) completing the precipitation of the doped titanium oxide particles by adding the second mixture to the first mixture until a pH of from about 2 to about 4 is reached.
1 more element
Dependencies are inferred from the claim text.