US4664894A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Micronized zirconia and method for production thereof
Assignee: Nippon Shokubai Co Ltd
•
Filing: 1985-08-06
•
Granted: 1987-05-12
•
Expires: 2005-08-06
Abstract
Abstract A method for the production of micronized zirconia by the addition of an alkali to an aqueous solution of a zirconium salt or to a mixed aqueous solution of said zirconium salt and a stabilizer such as yttrium, calcium, and magnesium compounds, which method comprises carrying out the reaction for formation of a hydroxide by the addition of the alkali continuously in a flow type reaction system while keeping the pH of said reaction system at a fixed level, separating the hydroxide produced consequently by the reaction, and drying and calcining the separated hydroxide, and a zirconia-containing micronized particle which contains such stabilizer and has an average particle diameter of not more than 0.02 μm.
Inventors
- 👤 Takehiko Suzuki
- 👤 Shigemi Osaka
- 👤 Norikazu Aikawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 13:32
CPC Classifications
C; C01; C01G; C01G25/00; C01G25/02; B; B82; B82Y; B82Y30/00; C01P; C01P2004/00; C01P2004/01; C01P2004/04; C01P2004/51; C01P2004/52; C01P2004/60; C01P2004/64; C01P2006/00; C01P2006/12
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
132 words
A method for the production of micronized zirconia by the addition of an alkali to an aqueous solution of a zirconium salt or to a mixed aqueous solution of said zirconium salt and a compound of at least one metal selected from the group consisting of yttrium, calcium, and magnesium, which method comprises carrying out the reaction for formation of a hydroxide by the addition of the alkali continuously in a flow type reaction system while keeping the pH of said reaction system adjusted accurately within ±0.5 of the fixed level in the range of 6.0 to 13.0, separating the hydroxide produced consequently by the reaction, washing with water to remove the alkali salt followed by dehydrating and drying with an organic solvent and subsequently spray drying and calcining the separated hydroxide.
Claim 2
Independent Claim
132 words
A method for the production of micronized zirconia by the addition of an alkali to an aqueous solution of a zirconium salt or to a mixed aqueous solution of said zirconium salt and a compound of at least one metal selected from the group consisting of yttrium, calcium, and magnesium, which method comprises carrying out the reaction for formation of a hydroxide by the addition of the alkali continuously in a flow type reaction system while keeping the pH of said reaction system adjusted accurately within ±0.5 of the fixed level in the range of 6.0 to 13.0, separating the hydroxide produced consequently by the reaction, washing with water to remove the alkali salt followed by dehydrating and drying with an organic solvent and subsequently spray drying and calcining the separated hydroxide.
Claim 3
Dependent Claim
25 words
A method according to claim 1, wherein the concentration of said zirconium salt (calculated as ZrO 2 ) is not more than about 2 mols/liter.
Claim 4
Dependent Claim
27 words
A method according to claim 2, wherein the concentration of said zirconium salt (calculated as ZrO 2 ) is in the range of 0.01 to 1.0 mol/liter.
Claim 5
Dependent Claim
18 words
A method according to claim 1, wherein the pH is adjusted accurately within ±0.2 of the fixed level.
Claim 6
Dependent Claim
11 words
A method according to claim 1, wherein said alkali is ammonia.
Claim 7
Dependent Claim
50 words
A method according to claim 1, wherein said compound of at least one metal selected from the group consisting of yttrium, calcium, and magnesium is contained in a concentration of not more than 0.5 mol as oxide, based on 1 mol of said zirconium salt calculated as ZrO 2 .
Claim 8
Dependent Claim
34 words
A method according to claim 6, wherein said compound is contained in a concentration of 0.02 to 0.3 mol as oxide, based on 1 mol of said zirconium salt calculated as ZrO 2 .
Claim 9
Independent Claim
151 words
A method for the production of micronized zirconia by the addition of an alkali to an aqueous solution of a zirconium salt or to a mixed aqueous solution of said zirconium salt and a compound of at least one metal selected from the group consisting of yttrium, calcium, and magnesium, which method comprises carrying out the reaction for formation of a hydroxide by the addition of the alkali continuously in a flow type reaction system while keeping the pH of said reaction system adjusted accurately within +0.5 of the fixed level in the range of 6.0 to 13.0, separating the hydroxide produced consequently by the reaction, washing with water to remove the alkali salt and drying and dehydrating the separated hyroxide in anhydrous lower alkanol and calcining to provide zirconia particles of average particle diameter of not more than 0.05 μm, having an average particle size variation not exceeding 0.02 μm.
Claim 10
Independent Claim
151 words
A method for the production of micronized zirconia by the addition of an alkali to an aqueous solution of a zirconium salt or to a mixed aqueous solution of said zirconium salt and a compound of at least one metal selected from the group consisting of yttrium, calcium, and magnesium, which method comprises carrying out the reaction for formation of a hydroxide by the addition of the alkali continuously in a flow type reaction system while keeping the pH of said reaction system adjusted accurately within +0.5 of the fixed level in the range of 6.0 to 13.0, separating the hydroxide produced consequently by the reaction, washing with water to remove the alkali salt and drying and dehydrating the separated hyroxide in anhydrous lower alkanol and calcining to provide zirconia particles of average particle diameter of not more than 0.05 μm, having an average particle size variation not exceeding 0.02 μm.
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) | 1990-05-11 | 1990-11-10 | 1991-05-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-05-11 | 1994-11-10 | 1995-05-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-05-11 | 1998-11-10 | 1999-05-12 | $7700.00 | Window Closed / Lapsed |