Patent US4268485A successfully refreshed from Google Patents.
US4268485A
Expired / Lapsed
US
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Process for the separation of radioactive impurities of baddeleyite
Assignee: Dynamit Nobel AG
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Filing: 1976-12-03
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Granted: 1981-05-19
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Expires: 1996-12-03
Abstract
Abstract A process for separating radioactive impurities from baddeleyite to obtain zirconium dioxide containing only traces of radioactive impurities, comprising grinding the baddeleyite preferably to a particle size of a maximum of 2% greater than 0.06 mm and then treating it directly with a 10 to 60% by weight aqueous alkali hydroxide solution at elevated temperatures below the boiling point of said solution at temperatures of 80° to 140° C. for 2 to 15 hours or until the desired degree of purity of the zirconium dioxide is obtained. In a preferred embodiment, sodium hydroxide is utilized and the ground baddeleyite preliminarily has been purified to the content of greater than 98% (zirconium dioxide+hafnium dioxide) by known methods.
Inventors
- 👤 Klaus Deneke
- 👤 Arnold Lenz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 01:05
CPC Classifications
G; G21; G21F; G21F9/00; G21F9/28; G21F9/30; G21F9/301; G21F9/302; G21F9/305; C; C01; C01G; C01G25/00; C01G25/02; C04; C04B; C04B35/00; C04B35/01; C04B35/48; C01P; C01P2006/00; C01P2006/80
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
74 words
A process for the separation of radioactive impurities from ground baddeleyite containing zirconium dioxide and which has been preliminarily purified to a concentrate containing more than 98% by weight of zirconium dioxide plus hafnium dioxide, comprising treating finely ground baddeleyite with an aqueous alkali hydroxide solution at elevated temperatures below the boiling point of said solution for removal of radioactive impurities form the ground baddeleyite and thereafter isolating said zirconium dioxide from said solution.
Claim 2
Dependent Claim
74 words
A process for the separation of radioactive impurities from ground baddeleyite containing zirconium dioxide and which has been preliminarily purified to a concentrate containing more than 98% by weight of zirconium dioxide plus hafnium dioxide, comprising treating finely ground baddeleyite with an aqueous alkali hydroxide solution at elevated temperatures below the boiling point of said solution for removal of radioactive impurities form the ground baddeleyite and thereafter isolating said zirconium dioxide from said solution.
Claim 3
Dependent Claim
26 words
A process as claimed in claim 1 wherein said finely ground baddeleyite has particle sizes of a maximum of 2% by weight greater than 0.06 mm.
Claim 4
Dependent Claim
24 words
A process as claimed in claim 1 wherein said treatment is carried out utilizing a 10 to 60% by weight aqueous alkali hydroxide solution
Claim 5
Dependent Claim
24 words
A process as claimed in claim 1 wherein said treatment is carried out utilizing a 20 to 50% by weight aqueous sodium hydroxide solution.
Claim 6
Dependent Claim
22 words
A process as claimed in claim 3 wherein said treatment is carried out at a temperature of from 80° to 140° C.
Claim 7
Dependent Claim
19 words
A process as claimed in claim 4 wherein said treatment is carried out for from 2 to 15 hours.
Claim 8
Dependent Claim
14 words
A process of claim 6, wherein said treatment is carried out at 80°-140° C.
Claim 9
Dependent Claim
20 words
Process of claim 1, wherein the radioactive impurities are reduced to a total radiation intensity of less than 300 pCi/g.
Claim 10
Dependent Claim
20 words
Process of claim 7, wherein the radioactive impurities are reduced to a total radiation intensity of less than 300 pCi/g.
Claim 11
Dependent Claim
14 words
A process as claimed in claim 1, wherein said alkali hydroxide is sodium hydroxide.
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) | 1984-05-18 | 1984-11-17 | 1985-05-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-05-18 | 1988-11-17 | 1989-05-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-05-18 | 1992-11-17 | 1993-05-19 | $7700.00 | Window Closed / Lapsed |