US3669624A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing high average pore volume silica
Assignee: WR Grace and Co
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Filing: 1970-07-09
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Granted: 1972-06-13
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Expires: 1990-07-09
Abstract
Abstract THE PRESENT PROCESS PRODUCES A HIGH PORE VOLUME SILICA OF ABOUT 2 TO 2.65 CC./G. WHERE SUBSTANTIALLY ALL OF THE PORE DIAMETER IS NARROWLY DISTRIBUTED BETWEEN ABOUT 100 A. TO 500 A. PORE DIAMETER. BY THE PRESENT PROCESS, SILICA IS SLURRIED IN A WEAK HYDROFLUORIC ACID SOLUTION FOLLOWED BY FILTRATION. THE WET SILICA IS WASHED THROUGHLY WITH ALCOHOL TO REMOVE ALL WATER AND ACID, AND DRIED. THE SILICA THEN IS GIVEN A MILD THERMAL TREATMENT. THE END PRODUCT SILICA HAS ABOUT A 50 PERCENT GREATER PORE VOLUME THAN AN UMPROCESSED SILICA.
Inventors
- 👤 John L Warthen
- 👤 Thomas H Cheavens
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 20:43
CPC Classifications
B; B01; B01J; B01J21/00; B01J21/06; B01J21/08; B01J20/00; B01J20/02; B01J20/10; B01J20/103; C; C01; C01B; C01B33/00; C01B33/113; C01B33/12; C01B33/14; C01B33/157; C09; C09C; C09C1/00; C09C1/28; C09C1/30; C09C1/309; C09C3/00; C09C3/04; C09C3/043; C09C3/06; C01P; C01P2006/00; C01P2006/14
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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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) | 1975-06-13 | 1975-12-13 | 1976-06-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-13 | 1979-12-13 | 1980-06-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-13 | 1983-12-13 | 1984-06-13 | $7700.00 | Window Closed / Lapsed |