Patent US3170254A successfully refreshed from Google Patents.
US2716631A
Expired / Lapsed
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Nitric acid concentration
Assignee: Hercules Powder Co
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Filing: 1951-11-03
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Granted: 1955-08-30
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Expires: 1971-11-03
Abstract
No abstract record available.
Inventors
- 👤 Robert J Bechtel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:14
CPC Classifications
C; C01; C01B; C01B21/00; C01B21/20; C01B21/38; C01B21/44
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
152 words
THE METHOD OF CONCENTRATING A WEAK AQUEOUS NITRIC ACID SOLUTION WHICH COMPRISES FRACTIONALLY DISTILLING SAID NITRIC ACID SOLUTION IN A STRIPPING ZONE AND A RECTIFYING ZONE, THE INTRODUCTION OF SAID NITRIC ACID SOLUTION BEING MADE TO SAID STRIPPING ZONE; INTRODUCING A CONCENTRATED AQUEOUS SOLUTION OF AN ALKALINE EARTH METAL NITRATE TO SAID STRIPPING ZONE NOT BELOW THE POINT OF INTRODUCTION THERETO OF SAID NITRIC ACID SOLUTION; PASSING VAPORS OF NITRIC ACID AND WATER FROM THE TOP OF SAID STRIPPING ZONE TO SAID RECTIFYING ZONE; PASSING A LIQUID SOLUTION OF NITRIC ACID AND WATER FROM THE BOTTOM OF SAID RECTIFYING ZONE TO THE TOP OF SAID STRIPPING ZONE; RECOVERING SUBSTANTIALLY ALL OF THE NITRIC ACID ENTERING SAID STRIPPING ZONE IN A CONCENTRATED AQUEOUS SOLUTION FROM THE TOP OF SAID RECTIFYING ZONE; AND RECOVERING A DILUTE AQUEOUS SOLUTION OF SAID METAL NITRATE SUBSTANTIALLY FREE OF NITRIC ACID FROM THE BOTTOM OF SAID STRIPPING ZONE.
Claim 2
Independent Claim
152 words
THE METHOD OF CONCENTRATING A WEAK AQUEOUS NITRIC ACID SOLUTION WHICH COMPRISES FRACTIONALLY DISTILLING SAID NITRIC ACID SOLUTION IN A STRIPPING ZONE AND A RECTIFYING ZONE, THE INTRODUCTION OF SAID NITRIC ACID SOLUTION BEING MADE TO SAID STRIPPING ZONE; INTRODUCING A CONCENTRATED AQUEOUS SOLUTION OF AN ALKALINE EARTH METAL NITRATE TO SAID STRIPPING ZONE NOT BELOW THE POINT OF INTRODUCTION THERETO OF SAID NITRIC ACID SOLUTION; PASSING VAPORS OF NITRIC ACID AND WATER FROM THE TOP OF SAID STRIPPING ZONE TO SAID RECTIFYING ZONE; PASSING A LIQUID SOLUTION OF NITRIC ACID AND WATER FROM THE BOTTOM OF SAID RECTIFYING ZONE TO THE TOP OF SAID STRIPPING ZONE; RECOVERING SUBSTANTIALLY ALL OF THE NITRIC ACID ENTERING SAID STRIPPING ZONE IN A CONCENTRATED AQUEOUS SOLUTION FROM THE TOP OF SAID RECTIFYING ZONE; AND RECOVERING A DILUTE AQUEOUS SOLUTION OF SAID METAL NITRATE SUBSTANTIALLY FREE OF NITRIC ACID FROM THE BOTTOM OF SAID STRIPPING ZONE.
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) | 1958-08-29 | 1959-02-28 | 1959-08-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1962-08-29 | 1963-02-28 | 1963-08-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1966-08-29 | 1967-02-28 | 1967-08-30 | $7700.00 | Window Closed / Lapsed |