US3859115A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of coated TiO{HD 2 {B pigments
Assignee: British Titan Ltd
•
Filing: 1973-03-02
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Granted: 1975-01-07
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Expires: 1993-03-02
Abstract
Abstract Treatment of titanium dioxide by adding to an aqueous suspension thereof containing a water-soluble silicate an acidic source of a soluble oxide of aluminium while maintaining the pH of the suspension at a value of from 3 to 4.5 to precipitate a hydrous oxide of silicon and then completing the precipitation of the hydrous oxide of aluminium by raising the pH of the suspension.
Inventors
- 👤 Thomas James Wiseman
- 👤 Peter Barry Howard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 13:47
CPC Classifications
C; C09; C09C; C09C1/00; C09C1/36; C01; C01P; C01P2004/00; C01P2004/80; C01P2004/82; C01P2004/84
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
85 words
A PROCESS FOR THE PRODUCTION OF PIGMENTARY TITANIUN DIOXIDE WHICH COMPRISES FORMING AN AQUEOUS SUSPENSION OR SLURRY OF PARTICLES OF TITANIUM DIOXIDE CONTAINING A WATERSOLUBLE SILICATE, ADDING AN ACIDIC WATER SOLUBLE SALT OF ALUMINIUM WHILE MAINTANING THE PH OF THE SUSPENSION AT A VALVE OF 3 TO 4.5 AND THEREEBY PRECIPITATINGA HYDROUS OXIDE OF SILICON ON THE PARTICLES AND RAISING THE PH OF THE SUSPENSION OR SLURRY TO EFFECT COMPLETE PRECIPITATION OF A HYDROUS OXIDE OF ALUMINIUM ON THE HYDROUS OXIDE OF SILICON COATED PARTICLES.
Claim 2
Dependent Claim
85 words
A PROCESS FOR THE PRODUCTION OF PIGMENTARY TITANIUN DIOXIDE WHICH COMPRISES FORMING AN AQUEOUS SUSPENSION OR SLURRY OF PARTICLES OF TITANIUM DIOXIDE CONTAINING A WATERSOLUBLE SILICATE, ADDING AN ACIDIC WATER SOLUBLE SALT OF ALUMINIUM WHILE MAINTANING THE PH OF THE SUSPENSION AT A VALVE OF 3 TO 4.5 AND THEREEBY PRECIPITATINGA HYDROUS OXIDE OF SILICON ON THE PARTICLES AND RAISING THE PH OF THE SUSPENSION OR SLURRY TO EFFECT COMPLETE PRECIPITATION OF A HYDROUS OXIDE OF ALUMINIUM ON THE HYDROUS OXIDE OF SILICON COATED PARTICLES.
Claim 3
Dependent Claim
27 words
A process according to claim 1 in which the pH is maintained at a value of from 3.5 to 4.2 while adding the acidic salt of aluminium.
Claim 4
Dependent Claim
20 words
A process according to claim 1 in which the pH is maintained at a value of from 3.8 to 4.2.
Claim 5
Dependent Claim
24 words
A process according to claiM 1 in which an alkali is added to the suspension or slurry simultaneously with the acidic salt of aluminium.
Claim 6
Dependent Claim
30 words
a process according to claim 1 in which a source of a phosphate is added to the aqueous suspension or slurry after the addition of the acidic salt of aluminium.
Claim 7
Dependent Claim
29 words
A process according to claim 1 in which the pH of the suspension is raised to at least 5 to effect complete precipitation of the hydrous oxide of aluminium.
Claim 8
Dependent Claim
16 words
A process according to claim 6 in which the pH is raised to at least 7.5.
Claim 9
Dependent Claim
30 words
a process according to claim 1 in which the amount of the hydrous oxide of silicon precipitated is from 0.5% to 20% expressed as SiO2 on the weight of TiO2.
Claim 10
Dependent Claim
30 words
A process according to claim 8 in which the amount of hydrous oxide of silicon is from 2 to 6% by weight expressed as SiO2 on the weight of TiO2.
Claim 11
Dependent Claim
30 words
A process according to claim 1 in which the amount of hydrous oxide of aluminium which is precipitated is from 0.1% to 15% expressed as Al2O3 by weight of TiO2.
Claim 12
Dependent Claim
24 words
A process according to claim 10 in which the amount of hydrous oxide of aluminium is from 0.5 to 5% by weight of TiO2.
Claim 13
Dependent Claim
40 words
A process according to claim 1 in which sufficient of the acidic salt of aluminium is added to the suspension or slurry initially to precipitate the hydrous oxide of silicon followed by the remainder of the acidic salt of aluminium.
Claim 14
Dependent Claim
59 words
A process according to claim 1 in which after the precipitation of the hydrous oxide of aluminium a further coating is applied by adding to the suspension of titanium dioxide a water-soluble hydrolysable compound of aluminium, titanium, cerium zinc, zirconium or silicon and adjusting the pH of the suspension to effect precipitation of the coating on the coated particles.
Claim 15
Dependent Claim
26 words
A process according to claim 1 in which the titanium dioxide is rutile titanium dioxide pigment prepared by the vapour phase oxidation off a titanium tetrahalide.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-01-06 | 1978-07-08 | 1979-01-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-06 | 1982-07-08 | 1983-01-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-06 | 1986-07-08 | 1987-01-07 | $7700.00 | Window Closed / Lapsed |