US4572824A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for recovery of zirconium and acid from spent etching solutions
Assignee: General Electric Co
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Filing: 1984-11-01
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Granted: 1986-02-25
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Expires: 2004-11-01
Abstract
Abstract In the manufacture of nuclear fuel tubes spent etching solutions containing nitric acid, zirconium, and hydrofluoric acid are produced as waste. A serial treatment process is employed to recover the zirconium and to restore the solution to the desired acid concentration. These processes include solvent extraction for zirconium removal and aqueous removal using evaporation or distillation.
Inventors
- 👤 Bang M. Kim
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:35
CPC Classifications
C; C23; C23F; C23F1/00; C23F1/46; C01; C01G; C01G25/00; C01G25/003
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
151 words
A method for treating spent aqueous etchant containing zirconium, nitric acid, and hydrofluoric acid from a zirconium tube etching bath, said method comprising: contacting said zirconium bearing etchant solution with a first side of a first membrane disposed in a first chamber to produce zirconium depleted etchant; contacting the second side of said first membrane with a zirconium selective solvent; circulating said solvent which has been in contact with said second side of said first membrane in said first chamber so as to contact a first side of a second membrane disposed in a second chamber; recirculating the solvent which has been in contact with the first side of said second membrane so as to recontact the second side of said first membrane contacting the second side of said second membrane with a stripping solution; and removing water from said zirconium depleted etchant whereby the concentration of said acids is increased
Claim 2
Independent Claim
151 words
A method for treating spent aqueous etchant containing zirconium, nitric acid, and hydrofluoric acid from a zirconium tube etching bath, said method comprising: contacting said zirconium bearing etchant solution with a first side of a first membrane disposed in a first chamber to produce zirconium depleted etchant; contacting the second side of said first membrane with a zirconium selective solvent; circulating said solvent which has been in contact with said second side of said first membrane in said first chamber so as to contact a first side of a second membrane disposed in a second chamber; recirculating the solvent which has been in contact with the first side of said second membrane so as to recontact the second side of said first membrane contacting the second side of said second membrane with a stripping solution; and removing water from said zirconium depleted etchant whereby the concentration of said acids is increased
Claim 3
Dependent Claim
11 words
The method of claim 1 in which said solvent comprises DEHPA.
Claim 4
Dependent Claim
26 words
The method of claim 1 in which said solvent comprises a solution comprising DEHPA and material selected from the group consisting of kerosene and aromatic hydrocarbons.
Claim 5
Dependent Claim
27 words
The method of claim 1 in which said membrane based extractor process employs a stripping agent selected from the group consisting of hydrofluoric acid and ammonium fluoride.
Claim 6
Dependent Claim
24 words
The method of claim 4 in which the concentration of said stripping agent in an aqueous solution is between about 0.5 and 3 mole/liter.
Claim 7
Dependent Claim
14 words
The method of claim 1 in which said water removal is performed by evaporation.
Claim 8
Dependent Claim
14 words
The method of claim 1 in which said water removal is performed by distillation.
Claim 9
Dependent Claim
21 words
The method of claim 1 further including the step of returning said solution with concentrated nitric acid to said etching bath.
References Cited (Backward Citations)
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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) | 1989-02-24 | 1989-08-26 | 1990-02-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-02-24 | 1993-08-26 | 1994-02-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-02-24 | 1997-08-26 | 1998-02-25 | $7700.00 | Window Closed / Lapsed |