Patent US4238467A successfully refreshed from Google Patents.
US4238467A
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Method of producing yttrium oxide with particularly big particles
Assignee: FORSKINGSGRUPPE FOR SJELDNE JORDARTER A CORP OF KINGDOM OF NORWAY
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Filing: 1979-04-09
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Granted: 1980-12-09
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Expires: 1999-04-09
Abstract
Abstract Yttrium oxide with particularly big particles is formed by reacting yttrium ions with oxalate ions so that yttrium oxalate is precipitated. The precipitated yttrium oxalate is maintained at a temperature of 90°-100° C. for a period from 1/2 to 24 hours for formation of a crystal form of yttrium oxalate which can be dried and ignited to oxide without disintergrating. The heat-treatment can be combined with the precipitation and also with the subsequent drying and ignition to yttrium oxide.
Inventors
- 👤 Martin Dugan
- 👤 Norvald Gjelsvik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 16:04
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/41; C07C51/412; C01; C01F; C01F17/00; C01F17/20; C01F17/206; C01F17/218; C01P; C01P2004/00; C01P2004/60; C01P2004/61
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
72 words
A method of producing yttrium oxide particles with substantially all of the particles having a size greater than five microns comprising: (a) precipitating yttrium oxalate; (b) maintaining the yttrium oxalate in a liquid medium at a temperature of 90°-100° C. for at least three hours whereby yttrium oxalate crystals are formed; (c) drying the yttrium oxalate crystals; (d) calcining the yttrium oxalate crystals whereby the yttrium oxalate is converted to yttrium oxide.
Claim 2
Independent Claim
72 words
A method of producing yttrium oxide particles with substantially all of the particles having a size greater than five microns comprising: (a) precipitating yttrium oxalate; (b) maintaining the yttrium oxalate in a liquid medium at a temperature of 90°-100° C. for at least three hours whereby yttrium oxalate crystals are formed; (c) drying the yttrium oxalate crystals; (d) calcining the yttrium oxalate crystals whereby the yttrium oxalate is converted to yttrium oxide.
Claim 3
Dependent Claim
14 words
The method of claim 1 wherein steps (a) and (b) are carried out simultaneously.
Claim 4
Dependent Claim
15 words
The method of claim 1 wherein steps (a)-(d) are carried out in one continuous process.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-12-09 | 1984-06-09 | 1984-12-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-12-09 | 1988-06-09 | 1988-12-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-12-09 | 1992-06-09 | 1992-12-09 | $7700.00 | Window Closed / Lapsed |