Patent US3681013A successfully refreshed from Google Patents.
US3681013A
Expired / Lapsed
US
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Extraction of alumina from bauxite
Assignee: Alcoa Corp
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Filing: 1970-02-02
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Granted: 1972-08-01
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Expires: 1990-02-02
Abstract
Abstract PRELIMINARY LOW-PRESSURE DIGESTION EXTRACTS ALUMINA FROMA COARSE FRACTION OF BAUXITE. FINES SEPARATED FROM THE COARSE FRACTION ARE ALSO PASSED ON FOR SUPER-ATMOSPHERIC DIGESTION.
Inventors
- 👤 William M Fish
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 21:33
CPC Classifications
C; C01; C01F; C01F7/00; C01F7/02; C01F7/04; C01F7/06; C01F7/062; B; B01; B01D; B01D11/00; B01D11/02; B01D11/028
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) | 1975-08-01 | 1976-01-31 | 1976-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-01 | 1980-01-31 | 1980-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-01 | 1984-01-31 | 1984-08-01 | $7700.00 | Window Closed / Lapsed |