Patent US3697255A successfully refreshed from Google Patents.
US3697255A
Expired / Lapsed
US
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Scrap tantalum reclamation process
Assignee: AT&T Inc
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Filing: 1970-11-17
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Granted: 1972-10-10
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Expires: 1990-11-17
Abstract
Abstract SCRAP TANTALUM BODIES HAVING IMPURITIES THEREIN ARE RECLAIMED AS SUBSTANTIALLY PURE TANTALUM METAL BY A PROCESS WHICH INCLUDES IMMERSING THE BODIES IN A MOLTEN METAL SUCH AS CALCIUM OR MAGNESIUM AT ELEVATED TEMPERATURES, AND UNDER NON-OXIDIZING CONDITIONS FOR A PROLONGED PERIOD OF TIME SUFFICIENT TO CAUSE ENTRAPPED IMPURITIES WITHIN THE BODY TO DIFFUSE OUT AND REACT WITH THE MOLTEN METAL.
Inventors
- 👤 Wiley M Baldwin
- 👤 Edward O Fuchs
- 👤 Donald J Sharp
- 👤 James H Swisher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:24
CPC Classifications
C; C22; C22B; C22B34/00; C22B34/20; C22B34/24
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) | 1975-10-10 | 1976-04-10 | 1976-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-10 | 1980-04-10 | 1980-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-10 | 1984-04-10 | 1984-10-10 | $7700.00 | Window Closed / Lapsed |