Patent US4933154A successfully refreshed from Google Patents.
US4933154A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of ZrO2 powder of very fine particle size
Assignee: Westinghouse Electric Corp
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Filing: 1987-01-30
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Granted: 1990-06-12
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Expires: 2007-01-30
Abstract
Abstract A ZrO 2 powder of very fine particle size adapted especially for the making of high density ceramics is produced by chlorinating a zirconium source material, such as zircon sand, to produce crude ZrCl 4 solids; the solids are dissolved to form a ZrOCl 2 solution from which ZrOCl 2 crystals are precipitated; the crystals are dried and milled to a desired particle size; and the crystal particles are subjected to direct oxidation under controlled conditions to produce a very fine ZrO 2 powder especially adapted to the making of high density ceramics.
Inventors
- 👤 Young J. Kwon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 09:01
CPC Classifications
C; C01; C01G; C01G25/00; C01G25/02; C01P; C01P2004/00; C01P2004/60; C01P2004/61; C01P2004/62
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
105 words
A process for producing a ZrO 2 powder of very fine particle size for use in making high density ceramics, comprising subjecting a zirconium source material to chlorination for producing crude ZrCl 4 solids; dissolving said solids in a medium in which zirconium oxychloride crystals will form and from which they will precipitate; forming zirconium oxychloride crystals in and precipitating them from said medium; drying said crystals; milling the dry crystals to controlled particle size; and directly oxidizing the resulting crystal particles under controlled conditions to yield a very fine zirconium oxide powder of particle size especially adapted to the making of high density ceramics.
Claim 2
Dependent Claim
105 words
A process for producing a ZrO 2 powder of very fine particle size for use in making high density ceramics, comprising subjecting a zirconium source material to chlorination for producing crude ZrCl 4 solids; dissolving said solids in a medium in which zirconium oxychloride crystals will form and from which they will precipitate; forming zirconium oxychloride crystals in and precipitating them from said medium; drying said crystals; milling the dry crystals to controlled particle size; and directly oxidizing the resulting crystal particles under controlled conditions to yield a very fine zirconium oxide powder of particle size especially adapted to the making of high density ceramics.
Claim 3
Dependent Claim
32 words
A process according to claim 1, wherein the medium in which the crude ZrCl 4 solids are dissolved is water and the resulting solution is filtered for the removal of undissolved matter.
Claim 4
Dependent Claim
22 words
A process according to claim 2, wherein the forming and precipitating of zirconium oxychloride is carried out in a continuous evaporative crystallizer.
Claim 5
Dependent Claim
19 words
A process according to claim 3, wherein the drying of the crystals is carried out in a vacuum dryer.
Claim 6
Dependent Claim
29 words
A process according to claim 1, wherein the milling of the dry crystals is controlled to produce particle size in the range of about 0.1 to about 1.0 microns.
Claim 7
Dependent Claim
34 words
A process according to claim 5, wherein the oxidizing of the crystal particles is controlled to yield a zirconium oxide powder of particle size within the range of about 0.1 to about 0.5 microns.
Claim 8
Dependent Claim
28 words
A process according to claim 6, wherein crystallization of zirconium oxychloride is controlled to yield crystals of size in the range of about 1.0 to about 50 microns.
Claim 9
Dependent Claim
15 words
A process according to claim 2, wherein the zirconium source material is a zircon sand.
Claim 10
Dependent Claim
15 words
A process according to claim 1, wherein the zirconium source material is a zircon sand.
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) | 1993-06-11 | 1993-12-11 | 1994-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-06-11 | 1997-12-11 | 1998-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-06-11 | 2001-12-11 | 2002-06-12 | $7700.00 | Window Closed / Lapsed |