US4933158A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for purifying nitrogen trifluoride gas
Assignee: Mitsui Chemicals Inc
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Filing: 1989-10-24
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Granted: 1990-06-12
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Expires: 2009-10-24
Abstract
Abstract There is here disclosed a method for removing nitrous oxide (N 2 O), carbon dioxide (CO 2 ) and dinitrogen difluoride (N 2 F 2 ) from a nitrogen trifluoride gas. The present invention is directed to a method for purifying a nitrogen trifluoride gas which comprises the steps of thermally treating, at a temperature of 250° to 700° C., a zeolite selected from the group consisting of analcime, clinoptilolite, mordenite, ferrierite, phillipsite, chabazite, erionite and laumotite; forming a packed bed of the treated zeolite; and passing the nitrogen trifluoride gas containing the gaseous impurities at a temperature of -125° to 50° C. through the filler layer.
Inventors
- 👤 Makoto Aritsuka
- 👤 Naruyuki Iwanaga
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 20:31
CPC Classifications
C; C01; C01B; C01B21/00; C01B21/082; C01B21/083; C01B21/0832; C01B21/0835; C01B21/0837
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
70 words
A method for purifying a nitrogen trifluoride gas which comprises the steps of thermally treating, at a temperature of 250° to 700° C., a natural zeolite selected from the group consisting of analcime, clinoptilolite, mordenite, ferrierite, phillipsite, chabazite, erionite and laumontite; forming a packed bed of said treated zeolite; and passing said nitrogen trifluoride gas containing gaseous impurities at a temperature of -125° to 50° C. through said packed bed.
Claim 2
Independent Claim
70 words
A method for purifying a nitrogen trifluoride gas which comprises the steps of thermally treating, at a temperature of 250° to 700° C., a natural zeolite selected from the group consisting of analcime, clinoptilolite, mordenite, ferrierite, phillipsite, chabazite, erionite and laumontite; forming a packed bed of said treated zeolite; and passing said nitrogen trifluoride gas containing gaseous impurities at a temperature of -125° to 50° C. through said packed bed.
Claim 3
Dependent Claim
33 words
The method for purifying a nitrogen trifluoride gas according to claim 1 wherein said gaseous impurities in said nitrogen trifluoride gas are N 2 O, CO 2 and N 2 F 2 .
Claim 4
Dependent Claim
31 words
The method for purifying a nitrogen trifluoride gas according to claim 1 wherein said thermal treatment of said zeolite is carried out for a period of 10 minutes to 80 hours.
Claim 5
Dependent Claim
28 words
The method for purifying a nitrogen trifluoride gas according to claim 1 wherein said thermal treatment of said zeolite is carried out while an inert gas is fed.
Claim 6
Dependent Claim
46 words
The method for purifying a nitrogen trifluoride gas according to claim 1 wherein said thermal treatment of said zeolite is carried out by heating said packed bed of said zeolite, and successively said nitrogen trifluoride gas containing said gaseous impurities is passed through said packed bed.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-06-11 | 1993-12-11 | 1994-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-06-11 | 1997-12-11 | 1998-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-06-11 | 2001-12-11 | 2002-06-12 | $7700.00 | Window Closed / Lapsed |