US4654173A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Nuclear waste solutions
Assignee: United States Department of Energy
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Filing: 1985-11-21
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Granted: 1987-03-31
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Expires: 2005-11-21
Abstract
Abstract High efficiency removal of technetium values from a nuclear waste stream is achieved by addition to the waste stream of a precipitant contributing tetraphenylphosphonium cation, such that a substantial portion of the technetium values are precipitated as an insoluble pertechnetate salt.
Inventors
- 👤 Darrel D. Walker
- 👤 Martha A. Ebra
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 23:13
CPC Classifications
G; G21; G21F; G21F9/00; G21F9/04; G21F9/06; G21F9/10
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
86 words
A process for the removal of technetium values from a nuclear waste solution which contains an initial, Tc-99, concentration in the range of about 2.5×10 -5 to 1×10 -4 molar, comprising the steps of (1) contacting said solution with a precipitation agent that contributes to said solution an amount of tetraphenylphosphonium cation sufficient to precipitate at least a portion of said technetium values out of said waste solution as an insoluble pertechnetate salt precipitate and then (2) separating said pertechnetate salt precipitate from said waste solution.
Claim 2
Dependent Claim
86 words
A process for the removal of technetium values from a nuclear waste solution which contains an initial, Tc-99, concentration in the range of about 2.5×10 -5 to 1×10 -4 molar, comprising the steps of (1) contacting said solution with a precipitation agent that contributes to said solution an amount of tetraphenylphosphonium cation sufficient to precipitate at least a portion of said technetium values out of said waste solution as an insoluble pertechnetate salt precipitate and then (2) separating said pertechnetate salt precipitate from said waste solution.
Claim 3
Dependent Claim
16 words
A process according to claim 1, wherein said precipitating agent comprises a water soluble tetraphenylphosphonium salt.
Claim 4
Dependent Claim
16 words
A process according to claim 2, wherein said salt is a water soluble tetraphenylphosphonium halide salt.
Claim 5
Dependent Claim
26 words
A process according to claim 2, wherein said precipitating agent comprises at least one compound selected from the group consisting of tetraphenylphosphonium chloride and tetraphenylphosphonium hydroxide.
Claim 6
Dependent Claim
27 words
A process according to claim 1, wherein said portion of said technetium values precipitated out of said waste solution ranges between at least 90% and about 96%.
Claim 7
Dependent Claim
21 words
A process according to claim 1, wherein step (2) comprises removing said pertechnetate salt precipitate from said waste solution by filtering.
Claim 8
Dependent Claim
20 words
A process according to claim 1, wherein said waste solution has a sodium ion concentration of at least 5.6 molar.
Claim 9
Dependent Claim
18 words
A process according to claim 1, further comprising prior to step (2) the step of concentrating said precipitate.
Claim 10
Dependent Claim
16 words
A process according to claim 8, wherein concentration of said precipitate is effected by cross-flow filtration.
Claim 11
Dependent Claim
21 words
A process according to claim 1, wherein said amount of tetraphenylphosphonium cation is between about 7×10 -4 and 2×10 -3 molar.
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) | 1990-03-30 | 1990-09-29 | 1991-03-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-03-30 | 1994-09-29 | 1995-03-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-03-30 | 1998-09-29 | 1999-03-31 | $7700.00 | Window Closed / Lapsed |