US3979334A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Manufacture of spheroidal alumina particles
Assignee: Universal Oil Products Co
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Filing: 1975-04-16
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Granted: 1976-09-07
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Expires: 1995-04-16
Abstract
Abstract Spheroidal alumina particles of improved physical stability are prepared in greater yield by aging an alumina hydrosol-hexamethylene-tetramine mixture prior to dispersing the same as droplets in a hot oil bath with the formation of spheroidal hydrogel particles.
Inventors
- 👤 Richard K. Lee
- 👤 John C. Foley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:54
CPC Classifications
B; B01; B01J; B01J37/00; B01J2/00; B01J2/02; B01J2/06; B01J2/08; B01J21/00; B01J21/02; B01J21/04; B01J35/00; B01J35/50; B01J35/51; C; C01; C01F; C01F7/00; C01F7/02; C01P; C01P2004/00; C01P2004/30; C01P2004/32
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
131 words
A method of manufacturing spheroidal alumina particles which comprises: a. commingling an acidic alumina hydrosol with an ammonia precursor at below gelation temperature and forming a mixture comprising from about 6 to 10 wt. % aluminum and from about 1:1 to about 1.5:1 weight ratio of aluminum to the acid anion content thereof, said precursor being hydrolyzable to ammonia with increasing temperature, and aging the mixture with stirring at a temperature of from 2° to about 25°C. for a period of from about 1 to about 4 hours; b. dispersing the aged mixture as droplets in a hot oil bath and forming hydrogel spheres therein; c. aging said spheres at an elevated temperature effecting decomposition of the residual ammonia precursor contained therein; and d. washing, drying and calcining the aged spheres.
Claim 2
Independent Claim
131 words
A method of manufacturing spheroidal alumina particles which comprises: a. commingling an acidic alumina hydrosol with an ammonia precursor at below gelation temperature and forming a mixture comprising from about 6 to 10 wt. % aluminum and from about 1:1 to about 1.5:1 weight ratio of aluminum to the acid anion content thereof, said precursor being hydrolyzable to ammonia with increasing temperature, and aging the mixture with stirring at a temperature of from 2° to about 25°C. for a period of from about 1 to about 4 hours; b. dispersing the aged mixture as droplets in a hot oil bath and forming hydrogel spheres therein; c. aging said spheres at an elevated temperature effecting decomposition of the residual ammonia precursor contained therein; and d. washing, drying and calcining the aged spheres.
Claim 3
Dependent Claim
19 words
The method of claim 1 further characterized with respect to step (a) in that said ammonia precursor is hexamethylenetetramine.
Claim 4
Dependent Claim
29 words
The method of claim 1 further characterized with respect to step (a) in that said mixture is aged at a temperature of from about 15° to about 22° C.
Claim 5
Dependent Claim
38 words
The method of claim 1 further characterized with respect to step (a) in that said ammonia precursor is utilized in an amount to effect substantially complete neutralization of the acid anion content of said mixture upon total hydrolysis.
Claim 6
Dependent Claim
32 words
The method of claim 2 further characterized with respect to step (a) in that said hexamethylenetetramine is utilized in from about a 1:4 to about 1.25:4 mole ratio with said acid anion.
Claim 7
Dependent Claim
30 words
The method of claim 1 further characterized with respect to step (b) in that said oil bath is maintained at a temperature of from about 50° to about 105° C.
Claim 8
Dependent Claim
29 words
The method of claim 1 further characterized with respect to step (c) in that said spheres are aged at a temperature of from about 50° to about 105° C.
Claim 9
Dependent Claim
44 words
The method of claim 1 further characterized with respect to step (c) in that said spheres are aged at a temperature of from about 50° to about 260° C. and at a pressure to maintain the water content thereof in a substantially liquid phase.
Claim 10
Dependent Claim
41 words
The method of claim 1 further characterized with respect to step (c) in that said spheres are aged at a temperature of from about 50° to about 160° C. and at a pressure of from about 40 to about 150 psig.
Claim 11
Dependent Claim
29 words
The method of claim 1 further characterized with respect to step (d) in that said spheres are calcined at a temperature of from about 425° to about 760° C.
References Cited (Backward Citations)
US2620314A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-09-07 | 1980-03-08 | 1980-09-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-09-07 | 1984-03-08 | 1984-09-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-09-07 | 1988-03-08 | 1988-09-07 | $7700.00 | Window Closed / Lapsed |