Patent US5456899A successfully refreshed from Google Patents.
US5456899A
Expired / Lapsed
US
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Preparation of titanium dioxide
Assignee: Tioxide Specialties Ltd
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Filing: 1994-02-04
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Granted: 1995-10-10
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Expires: 2014-02-04
Abstract
Abstract A novel process for preparing titanium dioxide from a titanium chloride consists of heating an aqueous solution of the titanium chloride in the presence of a salt of a polycarboxylic acid. The process is useful for producing titanium dioxide having a particle size between 0.1 and 1 micrometer and a purity which is suitable for more demanding electroceramic applications.
Inventors
- 👤 Paul Inchley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:57
CPC Classifications
C; C01; C01G; C01G25/00; C01G25/006; C01G23/00; C01G23/003; C01G23/006; C01G23/04; C01G23/047; C01G23/053; C01G23/0536; C01P; C01P2004/00; C01P2004/60; C01P2004/62; C01P2006/00; C01P2006/80
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
75 words
A process for the preparation of titanium dioxide powder comprising heating an aqueous solution of a titanium chloride in the presence of a salt of a polymeric carboxylic acid to precipitate titanium dioxide, wherein said salt is present at a concentration between about 0.01 and 2.0 percent, by weight, with respect to the titanium content of the solution expressed as TiO 2 and then drying the titanium dioxide precipitate to form the titanium dioxide powder.
Claim 2
Dependent Claim
75 words
A process for the preparation of titanium dioxide powder comprising heating an aqueous solution of a titanium chloride in the presence of a salt of a polymeric carboxylic acid to precipitate titanium dioxide, wherein said salt is present at a concentration between about 0.01 and 2.0 percent, by weight, with respect to the titanium content of the solution expressed as TiO 2 and then drying the titanium dioxide precipitate to form the titanium dioxide powder.
Claim 3
Dependent Claim
28 words
A process according to claim 1 in which the salt of a polymeric carboxylic acid is selected from the group consisting of ammonium salts and alkali metal salts.
Claim 4
Dependent Claim
30 words
A process according to claim 1 in which the salt of a polymeric carboxylic acid is selected from the group consisting of sodium polyacrylate, ammonium polyacrylate and sodium carboxymethyl cellulose.
Claim 5
Dependent Claim
28 words
A process according to claim 1 in which the titanium chloride solution has a concentration equivalent to between 100 and 500 grams TiO 2 per liter of solution.
Claim 6
Dependent Claim
22 words
A process according to claim 4 in which the concentration is from 300 to 500 grams TiO 2 per liter of solution.
Claim 7
Dependent Claim
47 words
A process according to claim 1 in which the salt of a polymeric carboxylic acid is present in the titanium chloride solution at a concentration between 0.05 and 2.0 per cent by weight with respect to the titanium content of the solution expressed as TiO 2 .
Claim 8
Dependent Claim
23 words
A process according to claim 1 in which the solution of titanium chloride is heated to a temperature of at least 80° C.
Claim 9
Dependent Claim
17 words
A process according to claim 7 in which the temperature is between 100° C. and 110° C.
Claim 10
Dependent Claim
19 words
A process according to claim 1 in which the solution of titanium chloride is slowly added to heated water.
Claim 11
Dependent Claim
21 words
A process according to claim 9 in which the salt of a polymeric carboxylic acid is dissolved in the heated water.
Claim 12
Dependent Claim
21 words
A process according to claim 1 in which the solution of titanium chloride is heated for from 3 to 5 hours.
Claim 13
Dependent Claim
28 words
A process according to claim I in which the titanium dioxide is separated from the aqueous solution and dried at a temperature between 200° C. and 1000° C.
Claim 14
Dependent Claim
17 words
A process according to claim 12 in which the temperature is between 600° C. and 900° C.
Claim 15
Dependent Claim
31 words
A process according to claim 1 in which the titanium dioxide is simultaneously separated and dried by subjecting the slurry which is produced by heating the titanium chloride solution to spray-drying.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-10-09 | 1999-04-10 | 1999-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-10-09 | 2003-04-10 | 2003-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-10-09 | 2007-04-10 | 2007-10-10 | $7700.00 | Window Closed / Lapsed |