Patent US4140773A successfully refreshed from Google Patents.
US4140773A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of high pore volume alumina spheres
Assignee: Vista Chemical Co
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Filing: 1978-02-24
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Granted: 1979-02-20
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Expires: 1998-02-24
Abstract
Abstract High macro-pore content spheres (>1000A) are produced by use of a rotating wheel, wherein dry alumina is dropped onto the wheel under a peptizing spray misted onto the wheel through an atomizing device. Compressive stresses normally encountered in procedures such as pelletizing are avoided, thereby preserving macro-pores. Size of spheres can be adjusted by altering, for example, the angle at which the wheel rotates.
Inventors
- 👤 Donald E. Stowell
- 👤 Larry L. Bendig
- 👤 John F. Scamehorn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 16:13
CPC Classifications
C; C01; C01F; C01F7/00; C01F7/02; C01F7/34; C01F7/36; C01P; C01P2004/00; C01P2004/30; C01P2004/32; C01P2006/00; C01P2006/12; C01P2006/16
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
130 words
A method for producing alumina spheres having between about 25% and 40% of all pores above 1,000 angstroms in size, comprising (a) producing alumina powder by mixing water and aluminum alkoxide at a velocity of from about 40 feet per second to about 250 feet per second, wherein velocity is determined by the formula V = F/pA wherein V is velocity, F is rate of flow in pounds per second, p is density in pounds per cubic foot, and A is orifice area in square feet; passing the admixture into a hydrolysis reactor; (b) allowing hydrolysis to occur, removing alumina and drying to obtain a high pore volume powder, and (c) dropping the dried high pore volume alumina onto a rotating wheel under a peptizing spray misted onto the wheel.
Claim 2
Independent Claim
130 words
A method for producing alumina spheres having between about 25% and 40% of all pores above 1,000 angstroms in size, comprising (a) producing alumina powder by mixing water and aluminum alkoxide at a velocity of from about 40 feet per second to about 250 feet per second, wherein velocity is determined by the formula V = F/pA wherein V is velocity, F is rate of flow in pounds per second, p is density in pounds per cubic foot, and A is orifice area in square feet; passing the admixture into a hydrolysis reactor; (b) allowing hydrolysis to occur, removing alumina and drying to obtain a high pore volume powder, and (c) dropping the dried high pore volume alumina onto a rotating wheel under a peptizing spray misted onto the wheel.
Claim 3
Dependent Claim
28 words
A method as described in claim 1 wherein the peptizing spray is an acid spray selected from the group consisting of nitric acid, acetic acid, and formic acid.
Claim 4
Dependent Claim
31 words
A method as described in claim 2 wherein the alumina powder peptizer spray ratio is by weight from about 1.7 to about 2.4 respectively (based on 3% nitric acid in spray).
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) | 1982-02-19 | 1982-08-21 | 1983-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-02-19 | 1986-08-21 | 1987-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-02-19 | 1990-08-21 | 1991-02-20 | $7700.00 | Window Closed / Lapsed |