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US2420852A
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US
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Recovery of alumina from ores
Assignee: NEPHELINE PRODUCTS Ltd
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Filing: 1942-09-24
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Granted: 1947-05-20
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Expires: 1962-09-24
Abstract
No abstract record available.
Inventors
- 👤 Archibald Frederick Ratcliffe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:48
CPC Classifications
C; C01; C01F; C01F7/00; C01F7/02; C01F7/04
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US1091230A
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US1283483A
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US1137860A
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US1422004A
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GB252399A
Cited
US1616674A
Cited
US1775313A
Cited
US1971354A
Cited
US2280998A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1950-05-19 | 1950-11-18 | 1951-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1954-05-19 | 1954-11-18 | 1955-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1958-05-19 | 1958-11-18 | 1959-05-20 | $7700.00 | Window Closed / Lapsed |