Patent US3537657A successfully refreshed from Google Patents.
US3537657A
Expired / Lapsed
US
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Process for the upgrading of potash minerals consisting essentially of sylvinite
Assignee: Wintershall AG
•
Filing: 1969-05-08
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Granted: 1970-11-03
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Expires: 1989-05-08
Abstract
No abstract record available.
Inventors
- 👤 Hans Henne
- 👤 Arno Singewald
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 22:37
CPC Classifications
B; B03; B03B; B03B5/00; B03B5/28; B03B5/30; B03B5/32; B03B5/34
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US2590756A
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US2668667A
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US2781906A
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US2738069A
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US2701641A
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US2932395A
Cited
GB887492A
Cited
US3063562A
Cited
US3331504A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1973-11-02 | 1974-05-04 | 1974-11-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-11-02 | 1978-05-04 | 1978-11-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-11-02 | 1982-05-04 | 1982-11-03 | $7700.00 | Window Closed / Lapsed |