Patent US3650931A successfully refreshed from Google Patents.
US3650931A
Expired / Lapsed
US
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Purification of reactive metals
Assignee: United States Department of the Interior
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Filing: 1969-06-05
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Granted: 1972-03-21
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Expires: 1989-06-05
Abstract
Abstract REACTIVE METALS, SUCH AS RARE-EARTH METALS, ARE PURIFIED BY ELECTROTRANSPORT IN A PULSED DIRECT CURRENT ELECTRIC FIELD. D R A W I N G
Inventors
- 👤 Thomas A Henrie
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 14:23
CPC Classifications
C; C22; C22B; C22B9/00; C22B9/02; C22B4/00; Y; Y02; Y02P; Y02P10/00; Y02P10/20
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) | 1975-03-21 | 1975-09-20 | 1976-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-21 | 1979-09-20 | 1980-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-21 | 1983-09-20 | 1984-03-21 | $7700.00 | Window Closed / Lapsed |