US3981978A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Working up aqueous titanium dioxide hydrate suspensions
Assignee: Bayer Antwerpen NV
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Filing: 1975-05-14
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Granted: 1976-09-21
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Expires: 1995-05-14
Abstract
Abstract In the recovery of titanium dioxide by subjecting an aqueous titanium dioxide hydrate suspension to at least one stage of filtering and washing to form a washed filter cake, adjusting the composition and calcining the adjusted and washed filter cake, the improvement which comprises filtering the aqueous titanium dioxide hydrate suspension under a pressure of about 1 bar to 16 bars to form a homogeneous substantially crack-free filter cake of a thickness of about 10 to 25 mm. Advantageously a membrane filter is employed, and washing is effected under a pressure of 1 to 16 bars and a liquid flow rate of 0.1 to 1 m/h to produce a filter cake having a solids content of at least 45 % by weight.
Inventors
- 👤 Raoul Weiler
- 👤 Henri Uwents
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:05
CPC Classifications
C; C01; C01G; C01G23/00; C01G23/04; C01G23/047; C01G23/0475
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
115 words
In the recovery of titanium dioxide by subjecting an aqueous titanium dioxide hydrate suspension to at least one stage of filtering to form a filter cake, adjusting the composition and calcining the adjusted filter cake, the improvement which comprises pressure filtering the aqueous titanium dioxide hydrate suspension in a membrane filter under a pressure of 3 bars to 16 bars to form a homogeneous substantially crack-free filter cake of a thickness of about 10 to 25 mm, and pressure washing the filter cake with liquid flowing at a rate of 0.1 to 1 m/h under a pressure of 1 bar to 16 bars with water containing 0.8 to 4 g of Ti 3 + /liter.
Claim 2
Dependent Claim
115 words
In the recovery of titanium dioxide by subjecting an aqueous titanium dioxide hydrate suspension to at least one stage of filtering to form a filter cake, adjusting the composition and calcining the adjusted filter cake, the improvement which comprises pressure filtering the aqueous titanium dioxide hydrate suspension in a membrane filter under a pressure of 3 bars to 16 bars to form a homogeneous substantially crack-free filter cake of a thickness of about 10 to 25 mm, and pressure washing the filter cake with liquid flowing at a rate of 0.1 to 1 m/h under a pressure of 1 bar to 16 bars with water containing 0.8 to 4 g of Ti 3 + /liter.
Claim 3
Dependent Claim
22 words
The process of claim 1, wherein the washed filter cake has a solid content of at least about 45 % by weight.
Claim 4
Dependent Claim
41 words
The process of claim 2, wherein pressure filtration is effected under a pressure of 3 to 6 bars and pressure washing is effected at a liquid flow rate of 0.3 to 0.7 m/h under a pressure of 4 to 10 bars.
References Cited (Backward Citations)
US2148283A
Cited
FR1422120A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-09-21 | 1980-03-22 | 1980-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-09-21 | 1984-03-22 | 1984-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-09-21 | 1988-03-22 | 1988-09-21 | $7700.00 | Window Closed / Lapsed |