US3859109A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pigment production
Assignee: British Titan Ltd
•
Filing: 1973-03-22
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Granted: 1975-01-07
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Expires: 1993-03-22
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 zirconium, hafnium or titanium while maintaining the pH of the suspension at a value in the range 1 to 3.5 to precipitate a hydrous oxide of silicon and thereafter raising the pH to effect the complete precipitation of the hydrous oxide of zirconium, hafnium or titanium.
Inventors
- 👤 Thomas James Wiseman
- 👤 Peter Barry Howard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 08:43
CPC Classifications
C; C09; C09C; C09C1/00; C09C1/36; C09C1/3607; C09C1/3653; C09C1/3661; C01; C01P; C01P2004/00; C01P2004/80; C01P2004/82; C01P2004/84
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
122 words
A PROCESS FOR THE PRODUCTION OF PIGMENTARY TITANIUM DIOXIDE WHICH COMPRISES FORMING AN AQUEOUS SUSPENSION OR SLURRY OF PARTICLES OF TITANIUM DIOXIDE CONTAINING A WATESOLUBLE SILICATE, REDUING THE PH OF SAID SUSPENSION TO A VALUE WITHIN THE RANGE OF 1.0 AND 3.5, ADDING TO THE ACIDIFIED SUSPENSION OR SLURRY A WATER-SOLUBLE ACIDIC COMPOUND OF A METAL SELECTED FROM THE CLASS CONSISTING OF ZIRCONIUM, HAFNIUM AND TITANIUM, AND AN ALKALI OR AN ALKALI METAL SILICATE, TO MAINTAIN THE PH OF THE SUSPENSION AT A VALUE OF 1 TO 3.5 AND THEREBY PRECIPITATING A HYDROUS OXIDE OF SILICON ON THE PARTICLES, AND RAISING THE PH OF THE SUSPENSIONN TO EFFECT COMPLETE PRECIPITATION OF A HYDROUS OXIDE OF ZIRCONIUM, HAFNIUM OR TITANIUM ON THE PARTICLES.
Claim 2
Dependent Claim
122 words
A PROCESS FOR THE PRODUCTION OF PIGMENTARY TITANIUM DIOXIDE WHICH COMPRISES FORMING AN AQUEOUS SUSPENSION OR SLURRY OF PARTICLES OF TITANIUM DIOXIDE CONTAINING A WATESOLUBLE SILICATE, REDUING THE PH OF SAID SUSPENSION TO A VALUE WITHIN THE RANGE OF 1.0 AND 3.5, ADDING TO THE ACIDIFIED SUSPENSION OR SLURRY A WATER-SOLUBLE ACIDIC COMPOUND OF A METAL SELECTED FROM THE CLASS CONSISTING OF ZIRCONIUM, HAFNIUM AND TITANIUM, AND AN ALKALI OR AN ALKALI METAL SILICATE, TO MAINTAIN THE PH OF THE SUSPENSION AT A VALUE OF 1 TO 3.5 AND THEREBY PRECIPITATING A HYDROUS OXIDE OF SILICON ON THE PARTICLES, AND RAISING THE PH OF THE SUSPENSIONN TO EFFECT COMPLETE PRECIPITATION OF A HYDROUS OXIDE OF ZIRCONIUM, HAFNIUM OR TITANIUM ON THE PARTICLES.
Claim 3
Dependent Claim
37 words
A process according to claim 1 wherein the pH of said suspension or slurry is reduced rapidly to a value within the range 1.0 to 3.5 by adding mineral acid to said suspension as quickly as possible.
Claim 4
Dependent Claim
25 words
A process according to claim 1 in which the pH of the suspension or slurry in maintained at a value of from 1.0 to 3.0.
Claim 5
Dependent Claim
32 words
A process according to claim 1 in which the acidic compound of zirconium is added to the suspension or slurry while maintaining the pH at a value of from 1.5 to 3.0.
Claim 6
Dependent Claim
32 words
A process according to claim 1 in which the acidic compound of hafnium is added to the suspension or slurry while maintaining the pH at a value of from 1.5 to 3.0.
Claim 7
Dependent Claim
32 words
A process according to claim 1 in which the acidic compound of titanium is added to the suspension or slurry while maintaining the pH at a value of from 2.5 to 3.5.
Claim 8
Dependent Claim
41 words
A process according to claim 1 in which a source of a phosphate selected from the group consisting of sodium dihydrogen phosphate and orthophosphoric acid is added to the aqueous suspension or slurry after the addition of the said acidic compound.
Claim 9
Dependent Claim
34 words
A process according to claim 1 in which the pH of the suspension or slurry is raised to at least 5 to effect complete precipitation of the hydrous oxide of zirconium, hafnium or titanium.
Claim 10
Dependent Claim
16 words
A process according to claim 8 in which the pH is raised to at least 7.5.
Claim 11
Dependent Claim
30 words
A process according to claim 1 in which the amount of hydrous oxide of silicon precipitated is from 0.5 to 20 percent expressed as SiO2 on the weight of TiO2.
Claim 12
Dependent Claim
29 words
A process according to claim 10 in which the amount of hydrous oxide of silicon is from 2 to 6 percent expressed as SiO2 on the weight of TiO2.
Claim 13
Dependent Claim
35 words
A process according to claim 1 in which the amount of hydrous oxide of zirconium, hafnium or titanium which is precipitated is from 0.1 to 15 percent expressed as the oxide by weight of TiO2.
Claim 14
Dependent Claim
35 words
A process according to claim 12 in which the amount of hydrous oxide of zirconium, hafnium or titanium which is precipitated is from 0.5 to 5 percent expressed as the oxide by weight of TiO2.
Claim 15
Dependent Claim
38 words
A process according to claim 12 in which sufficient of the said acidic compound is added to the suspension or slurry initially to precipitate the hydrous oxide of silicon followed by the remainder of the said acidic compound.
Claim 16
Dependent Claim
62 words
A process according to claim 1 in which after the precipitation of the hydrous oxide of zirconium, hafnium or titanium a further coating is applied by adding to the suspension or slurry of titanium dioxide a water-soluble hydrolysable compound of aluminium, titanium, cerium, zinc, zirconium or silicon and adjusting the ph of the suspension or slurry to effect precipitation of the coating.
Claim 17
Dependent Claim
25 words
A process according to claim 1 in which the titanium dioxide is rutile titanium dioxide pigment prepared by the vapour phase oxidation of titanium tetrachloride.
Claim 18
Dependent Claim
119 words
A process for the production of pigmentary titanium dioxide which consists essentially of forming an aqueous suspension of particles of titanium dioxide containing a water-soluble silicate, reducing the pH of said suspension to a value within the range 1.0 AND 3.5, adding to the so formed suspension a water-soluble acidic compound of a metal selected from the class consisting of zirconium, hafnium and titanium and sufficient alkali or alkali metal silicate to maintain the ph of the suspension at a value of 1 to 3.5 and thereby precipitating a hydrous oxide of silicon on the particles, and raising the pH of the suspension to effect complete precipitation of a hydrous oxide of zirconium, hafnium or titanium on the particles.
Claim 19
Dependent Claim
119 words
A process for the production of pigmentary titanium dioxide which consists essentially of forming an aqueous suspension of particles of titanium dioxide containing a water-soluble silicate, reducing the pH of said suspension to a value within the range 1.0 AND 3.5, adding to the so formed suspension a water-soluble acidic compound of a metal selected from the class consisting of zirconium, hafnium and titanium and sufficient alkali or alkali metal silicate to maintain the ph of the suspension at a value of 1 to 3.5 and thereby precipitating a hydrous oxide of silicon on the particles, and raising the pH of the suspension to effect complete precipitation of a hydrous oxide of zirconium, hafnium or titanium on the particles.
Claim 20
Dependent Claim
37 words
A process according to claim 17 wherein the pH of said suspension or slurry is reduced rapidly to a value within the range 1.0 and 3.5 by adding mineral acid to said suspension as quickly as possible.
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 |