US3528804A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Copper separation process
Assignee: Shell USA Inc
•
Filing: 1967-12-22
•
Granted: 1970-09-15
•
Expires: 1987-12-22
Abstract
No abstract record available.
Inventors
- 👤 Ernst L Th M Spitzer
- 👤 Johannes Radder
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 13:27
CPC Classifications
C; C01; C01G; C01G49/00; C01G49/10; C01G1/00; C01G1/06; C01G3/00; C01G3/003
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-09-14 | 1974-03-16 | 1974-09-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-09-14 | 1978-03-16 | 1978-09-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-09-14 | 1982-03-16 | 1982-09-15 | $7700.00 | Window Closed / Lapsed |