US3791992A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of a magnesium spinel catalyst base
Assignee: WR Grace and Co Conn
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Filing: 1972-10-06
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Granted: 1974-02-12
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Expires: 1992-10-06
Abstract
Abstract THE PRESENT INVENTION ID DIRECTED TO A PROCESS FOR PREPARING A SPINEL-CONTAINING CATALYST BASE CHARACTERIZED BY SHRINKAGE OF LESS THAN ABOUT 3 PERCENT AFTER HEATING TO TEMPERATURES IN EXCESS OF 1500*F. COMPRISING MIXING A SOLUTION OF A SOLUBLE ACID SALT OF DIVALENT MAGNESIUM WITH A SOLUTION OF AN ALKALI METAL ALUMINATE; SEPARATING AND WASHING THE RESULTING PRECIPITATE; EXCHANGING THE PRECIPITATE WITH AN AMMONIUM COMPOUND; FOLLOWED BY WASHING, DRYING, FORMING, AND CALCINATION. THE CATALYST BASE IS ESPECIALLY USEFUL FOR SUPPORTING AUTO EXHAUST CONVERSION CATALYSTS.
Inventors
- 👤 R Feldwick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 19:00
CPC Classifications
B; B01; B01J; B01J21/00; B01J21/005; B01D; B01D53/00; B01D53/34; B01D53/74; B01D53/86; B01J21/10; Y; Y10; Y10S; Y10S502/00; Y10S502/524
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) | 1977-02-11 | 1977-08-13 | 1978-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-11 | 1981-08-13 | 1982-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-11 | 1985-08-13 | 1986-02-12 | $7700.00 | Window Closed / Lapsed |