Patent US3591518A successfully refreshed from Google Patents.
US3591518A
Expired / Lapsed
US
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Silica aquasols and powders
Assignee: EIDP Inc
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Filing: 1968-12-31
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Granted: 1971-07-06
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Expires: 1988-12-31
Abstract
Abstract SILICA AQUASOLS ARE MADE BY PROVIDING A HEEL OF A SILICA SOL CONTAINING AQUEOUS AMMONIUM HYDROXIDE IN A REACTION VESSEL. FINELY DIVIDED SILICON METAL IS INTRODUCED INTO THE HEEL AND THE METAL AND WATER REACT TO FORM SILICA. THE CONCENTRATION AND SURFACE AREA OF THE SILICA IN THE HEEL AND THE PRODUCTION RATE OF SILICA IN THE REACTION MIXTURE ARE SUCH THAT THE SILICA FORMED POLYERIZES ON THE HEEL PARTICLES TO PROVIDED NOVEL, SPHERICAL SILICA PARTICLES HAVING A SURFACE AREA AVERAGE DIAMETER BETWEEN 150 AND 500 MU.
Inventors
- 👤 Donald Mcmillan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 11:04
CPC Classifications
C; C01; C01B; C01B33/00; C01B33/113; C01B33/12; C01B33/14; C01B33/141; C01B33/1412
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-07-05 | 1975-01-04 | 1975-07-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-07-05 | 1979-01-04 | 1979-07-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-07-05 | 1983-01-04 | 1983-07-06 | $7700.00 | Window Closed / Lapsed |