Patent US3712838A successfully refreshed from Google Patents.
US3712838A
Expired / Lapsed
US
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Regeneration of caustic liquor for etching aluminum
Assignee: Dow Chemical Co
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Filing: 1971-03-17
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Granted: 1973-01-23
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Expires: 1991-03-17
Abstract
Abstract THE PRESENT INVENTION IS A PROCESS FOR REGENERATING SPENT CAUSTIC ETCHING SOLUTIONS RESULTING FROM REACTING ALUMINUM WITH AQUEOUS SOLUTIONS CONTAINING FREE ALKALI METAL HYDROXIDE. IN PARTICULAR A SPENT CAUSTIC ETCHING LIQUOR, ORDINARILY AT THE ETCHING BATH TEMPERATURE, IS CONTACTED WITH CALCIUM OXIDE TO PRECIPITATE ALUMINUM VALUES PRESENT IN THE SPENT LIQUOR AND REGENERATE HYDROXYL IONS. THE PRECIPITATE IS REMOVED FROM THE REGENERATED SOLUTION. D R A W I N G
Inventors
- 👤 U Weissenberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 03:24
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/46
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) | 1976-01-23 | 1976-07-24 | 1977-01-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-23 | 1980-07-24 | 1981-01-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-23 | 1984-07-24 | 1985-01-23 | $7700.00 | Window Closed / Lapsed |