US3689217A
Expired / Lapsed
US
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Process for freeing 55-85% sulphuric acid from its impurities due to metals and/or semi-metals
Assignee: Inventa AG fuer Forschung und Patentverwertung
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Filing: 1970-06-15
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Granted: 1972-09-05
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Expires: 1990-06-15
Abstract
Abstract PROCESS FOR REMOVING METAL IMPURITITEDSUCH AS IRON FORM 55-85% BY WEIGHT SULPHURIC ACID. THE SULPHURIC ACID IS TREATED WITH A MOLAR EXCESS OF A HALIDE TO FORM A COMPLEX WITH THE IMPURITY. THE ACID IS THEN PASSED THROUGH AN ANION EXCHANGER TO PURIFY AND REMOVE THE IMPURITIES FROM THE ACID.
Inventors
- 👤 Marcel Capaul
- 👤 Hermann Sauter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:06
CPC Classifications
B; B01; B01J; B01J41/00; B01J41/04; C; C01; C01B; C01B17/00; C01B17/69; C01B17/90; C01B17/901; C01B17/904
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) | 1975-09-05 | 1976-03-06 | 1976-09-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-09-05 | 1980-03-06 | 1980-09-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-09-05 | 1984-03-06 | 1984-09-05 | $7700.00 | Window Closed / Lapsed |