US3674430A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the pyrogenic making of highly dispersed silicon dioxide
Assignee: Evonik Operations GmbH
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Filing: 1970-06-30
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Granted: 1972-07-04
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Expires: 1990-06-30
Abstract
Abstract SILICON DIOXIDE OR A MATERIAL CONTAINING THE SAME ARE REACTED WITH A REDUCING AGENT AT AN ELEVATED TEMPERATURE. THE HOT GAS CONTAINING THE SILICON MONOXIDE THUS FORMED IS THEN TREATED WITH STEAM WHEREBY A FINELY DISPERSED SILANE GROUPS- AND SILANOL GROUPS-CONTAINING SOLID INTERMEDIATE PRODUCT IS FORMED IN THE GAS STREAM WHICH IS THEN SUBJECTED TO CHILLING WHEREUPON THE MAJOR PORTION OF THE SOLID PRODUCT IS SEPARATED FROM THE RESIDUAL GAS AND IS FINALLY SUBJECTED TO A THERMAL AFTERTREATMENT AT ABOUT 1001000* C.
Inventors
- 👤 Alfred Illigen
- 👤 Walter Neugebauer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 19:48
CPC Classifications
C; C01; C01B; C01B33/00; C01B33/113; C01B33/12; C01B33/18; C01B33/181; C01B33/182; B; B82; B82Y; B82Y30/00; C01P; C01P2004/00; C01P2004/30; C01P2004/32; C01P2004/60; C01P2004/62; C01P2004/64; C01P2006/00; C01P2006/11; C01P2006/12; C01P2006/22; C01P2006/60; C01P2006/90
Claims Analysis
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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) | 1975-07-04 | 1976-01-03 | 1976-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-04 | 1980-01-03 | 1980-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-04 | 1984-01-03 | 1984-07-04 | $7700.00 | Window Closed / Lapsed |