Patent US3669644A successfully refreshed from Google Patents.
US3669644A
Expired / Lapsed
US
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Reclamation of copper from copper-clad steel
Assignee: SCM Metal Products Inc
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Filing: 1971-02-03
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Granted: 1972-06-13
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Expires: 1991-02-03
Abstract
Abstract CUPROUS POWDER OF DESIRABLE QUALITY IS PRODUCED BY ROASTING PIECES OF COPPER-CLAD FEROUS METAL SUCH AS STEEL IN AIR BETWEEN ABOUT 1500*F. AND ABOUT 1950*F. UNTIL COPPER-RICH SCALE IS FORMED CONTAINING MINOR IRON CONTENT; SEPARATING THE SCALE FROM BASE METAL; MAGNETICALLY CLEANING THE SEPARATED SCALE TO REMOVE IRON CONTENT THEREFROM.
Inventors
- 👤 Jack Sato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 15:06
CPC Classifications
C; C22; C22B; C22B15/00; C22B15/0026; C22B15/0056; C22B15/0002; C22B15/001; C22B15/0013; C22B15/0015; C22B7/00; C22B7/001; Y; Y02; Y02P; Y02P10/00; Y02P10/20
Claims Analysis
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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) | 1975-06-13 | 1975-12-13 | 1976-06-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-13 | 1979-12-13 | 1980-06-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-13 | 1983-12-13 | 1984-06-13 | $7700.00 | Window Closed / Lapsed |