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US4088737A
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Dry method for recycling iodine-loaded silver zeolite
Assignee: United States Department of Energy
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Filing: 1976-11-02
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Granted: 1978-05-09
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Expires: 1996-11-02
Abstract
Abstract Fission product iodine is removed from a waste gas stream and stored by passing the gas stream through a bed of silver-exchanged zeolite until the zeolite is loaded with iodine, passing dry hydrogen gas through the bed to remove the iodine and regenerate the bed, and passing the hydrogen stream containing the hydrogen iodide thus formed through a lead-exchanged zeolite which adsorbs the radioactive iodine from the gas stream and permanently storing the lead-exchanged zeolite loaded with radioactive iodine.
Inventors
- 👤 Thomas R. Thomas
- 👤 Bruce A. Staples
- 👤 Llewellyn P. Murphy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:42
CPC Classifications
G; G21; G21F; G21F9/00; G21F9/02; B; B01; B01D; B01D53/00; B01D53/02
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
71 words
A method of removing radioactive iodine from a waste gas stream and storing the same comprising: passing the waste gas through a silver-exchanged zeolite until the zeolite is loaded with iodine, passing hydrogen through the zeolite to remove the iodine as hydrogen iodide and regenerate the zeolite, passing the hydrogen stream containing the hydrogen iodide through a lead-exchanged zeolite until the zeolite is loaded with iodine and storing the radioactive-iodine-loaded zeolite.
Claim 2
Independent Claim
71 words
A method of removing radioactive iodine from a waste gas stream and storing the same comprising: passing the waste gas through a silver-exchanged zeolite until the zeolite is loaded with iodine, passing hydrogen through the zeolite to remove the iodine as hydrogen iodide and regenerate the zeolite, passing the hydrogen stream containing the hydrogen iodide through a lead-exchanged zeolite until the zeolite is loaded with iodine and storing the radioactive-iodine-loaded zeolite.
Claim 3
Dependent Claim
24 words
The method of claim 1 wherein the hydrogen is passed through the iodine-loaded silver-exchanged zeolite at a temperature of about 400° to 550° C.
Claim 4
Dependent Claim
27 words
The method of claim 2 wherein the hydrogen containing the hydrogen iodide is passed through the lead-exchanged zeolite at a temperature of about 80° to 250° C.
Claim 5
Dependent Claim
19 words
The method of claim 3 wherein the waste gas stream is at a temperature between ambient and 300° C.
Claim 6
Dependent Claim
20 words
The method of claim 4 wherein the zeolites are selected from the group consisting of zeolite X and zeolite Z.
Claim 7
Independent Claim
68 words
A method for regenerating iodine loaded silver-exchanged zeolite and recovering the iodine for storage comprising: passing an oxygen-free gas stream containing hydrogen through the iodine loaded silver-exchanged zeolite to desorb the iodine as hydrogen iodide thereby regenerating the silver zeolite; passing the gas stream containing the hydrogen iodide through lead-exchanged zeolite whereby the iodine is adsorbed on the lead-exchanged zeolite, and storing the lead-exchanged zeolite loaded with iodine.
Claim 8
Independent Claim
68 words
A method for regenerating iodine loaded silver-exchanged zeolite and recovering the iodine for storage comprising: passing an oxygen-free gas stream containing hydrogen through the iodine loaded silver-exchanged zeolite to desorb the iodine as hydrogen iodide thereby regenerating the silver zeolite; passing the gas stream containing the hydrogen iodide through lead-exchanged zeolite whereby the iodine is adsorbed on the lead-exchanged zeolite, and storing the lead-exchanged zeolite loaded with iodine.
Claim 9
Dependent Claim
26 words
The method of claim 6 wherein the gas stream is passed through the iodine loaded silver-exchanged zeolite at a temperature of about 400° - 550° C.
Claim 10
Dependent Claim
28 words
The method of claim 7 wherein the gas stream containing the hydrogen iodide is passed through the lead-exchanged zeolite at a temperature of about 80° to 250° C.
Claim 11
Dependent Claim
12 words
The method of claim 8 wherein the gas stream is pure hydrogen.
Claim 12
Dependent Claim
20 words
The method of claim 9 wherein the zeolite is selected from the group consisting of zeolite X and zeolite Y.
References Cited (Backward Citations)
US3658467A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-05-08 | 1981-11-07 | 1982-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-08 | 1985-11-07 | 1986-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-08 | 1989-11-07 | 1990-05-09 | $7700.00 | Window Closed / Lapsed |