US4179408A
Expired / Lapsed
US
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Process for preparing spheroidal alumina particles
Assignee: WR Grace and Co Conn
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Filing: 1977-03-25
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Granted: 1979-12-18
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Expires: 1997-03-25
Abstract
Abstract Spheroidal alumina particles have a combination of high macroporosity, surface area, crush strength and low attrition loss and bulk density. The particles are prepared by an improved external gelation oil-drop process. In the process a slurry of alumina, preferably a microcrystalline boehmite-pseudoboehmite intermediate, is prepared in an acidic aqueous medium and droplets of the slurry are passed through air into a column containing an upper body of water-immiscible liquid and ammonia and a lower body of aqueous coagulating agent. Catalysts employing the particles as a support and having catalytic agents distributed at controlled depths in the particle have excellent initial and sustained activity and durability, especially for eliminating pollutants in automotive exhaust streams.
Inventors
- 👤 Moises G. Sanchez
- 👤 Michael V. Ernest
- 👤 Norman R. Laine
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:05
CPC Classifications
B; B01; B01J; B01J35/00; B01J35/60; B01J21/00; B01J21/02; B01J21/04; C; C01; C01F; C01F7/00; C01F7/02; C01F7/021; C01F7/34; B01J35/61; B01J35/615; B01J35/63; B01J35/635; B01J35/638; B01J35/64; B01J35/647; B01J35/651; B01J35/653; C01P; C01P2002/00; C01P2002/60; C01P2004/00; C01P2004/30; C01P2004/32; C01P2004/60; C01P2004/61; C01P2006/00; C01P2006/10; C01P2006/11; C01P2006/12; C01P2006/14; C01P2006/16; C01P2006/17; C01P2006/21; C01P2006/22; Y; Y10; Y10S; Y10S502/00; Y10S502/50; Y10S502/503
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
71 words
A process for preparing spheroidal alumina particles comprising: (a) commingling a precipitated alumina and an acidic aqueous medium to provide a slurry; (b) forming droplets of the slurry; (c) passing the droplets downwardly through air into an upper body of water-immiscible liquid and ammonia and into a lower body comprising aqueous ammonia to form spheroidal particles; (d) aging the particles in aqueous ammonia; and (e) drying and calcining the aged particles.
Claim 2
Dependent Claim
71 words
A process for preparing spheroidal alumina particles comprising: (a) commingling a precipitated alumina and an acidic aqueous medium to provide a slurry; (b) forming droplets of the slurry; (c) passing the droplets downwardly through air into an upper body of water-immiscible liquid and ammonia and into a lower body comprising aqueous ammonia to form spheroidal particles; (d) aging the particles in aqueous ammonia; and (e) drying and calcining the aged particles.
Claim 3
Dependent Claim
37 words
The process of claim 1 wherein the alumina comprises a substantially pure, microcrystalline boehmite--pseudoboehmite intermediate having from about 70 to about 85% weight percent of the total amount of Al 2 O 3 present in crystalline form.
Claim 4
Dependent Claim
38 words
The process of claim 1 wherein the alumina has a [020] d spacing of about 6.2 to about 6.5 A, and has a mid-point width of the [020] X-ray diffraction peak of about 1.65 to about 1.85 A.
Claim 5
Dependent Claim
28 words
The process of claim 3 in which the slurry has a pH of about 4.0 to about 4.8 and a viscosity of about 200 to about 1600 cps.
Claim 6
Dependent Claim
34 words
The process of claim 3 in which the acidic aqueous medium is selected from the group consisting of aqueous solutions of nitric acid, hydrochloric acid, acetic acid, formic acid, aluminum nitrate and their mixtures.
Claim 7
Dependent Claim
28 words
The process of claim 5 in which the slurry contains from about 10 to about 40 weight percent alumina and about 1 to about 12 weight percent acid.
Claim 8
Dependent Claim
21 words
The process of claim 6 wherein the slurry has an acid to alumina molar ratio of about 0.05 to about 0.50.
Claim 9
Dependent Claim
30 words
The process of claim 3 in which the alumina and acidic aqueous medium are commingled by adding portions of the alumina to the acidic aqueous medium to acidify the alumina.
Claim 10
Dependent Claim
60 words
The process of claim 1 wherein the alumina comprises a microcrystalline boehmite-pseudoboehmite intermediate having a nitrogen pore volume of about 0.60 to about 0.75 cm. 3 /g. and a surface area of about 100 to about 150 m. 2 /g., said surface area and pore volume being determined after a thermal treatment for about 1 hour at about 1850° F.
Claim 11
Dependent Claim
45 words
The process of claim 1 wherein the alumina comprises a microcrystalline boehmite-pseudoboehmite intermediate in which about 130 to about 180 milliequivalents of sulfuric acid per mole of alumina will change the pH of a water slurry of the alumina from about 8.3 to about 4.0.
Claim 12
Dependent Claim
45 words
The process of claim 10 wherein the alumina comprises a microcrystalline boehmite-pseudoboehmite intermediate in which about 140 to about 160 milliequivalents of sulfuric acid per mole of alumina will change the pH of a water slurry of the alumina from about 8.3 to about 4.0.
Claim 13
Dependent Claim
73 words
The process of claim 1 wherein the alumina comprises a substantially pure, microcrystalline boehmite-pseudoboehmite intermediate having a [020] d spacing of about 6.3 to about 6.4 A., a nitrogen pore volume of about 0.64 to about 0.72 cm. 3 /g., and a surface area of about 110 to about 140 m. 2 /g., said pore volume and surface area being determined after a thermal treatment for about 1 hour at about 1850° F.
Claim 14
Dependent Claim
14 words
The process of claim 1 wherein the alumina comprises a washed alumina filter cake.
Claim 15
Dependent Claim
29 words
The process of claim 1 wherein the aged particles are calcined at about 1750° to about 1950° F. for a period from about 30 minutes to about 3 hours.
Claim 16
Dependent Claim
30 words
The process of claim 14 wherein the aged particles are calcined at from about 1800° to about 1900° F. for a period from about 1 hour to about 2 hours.
Claim 17
Dependent Claim
58 words
The process of claim 1 wherein the alumina is prepared by a precipitation in which aqueous solutions of sodium aluminate and aluminum sulfate are reacted so that the ratio of sodium expressed as moles of Na 2 O to sulfate ion expressed as moles of equivalent H 2 SO 4 is in excess of 0.80 but below 0.97.
Claim 18
Dependent Claim
16 words
The process of claim 16 wherein the ratio is in excess of 0.88 but below 0.97.
Claim 19
Dependent Claim
30 words
The process of claim 1 wherein the alumina also comprises calcined alumina fines produced in the process in an amount of up to about 15 percent of the total alumina.
Claim 20
Dependent Claim
30 words
The process of claim 13 wherein the alumina also comprises calcined alumina fines produced in the process in an amount of up to about 15 percent of the total alumina.
Claim 21
Dependent Claim
17 words
The process of claim 19 wherein the acidic aqueous medium comprises an aqueous solution of aluminum nitrate.
Claim 22
Dependent Claim
27 words
The process of claim 1 wherein the acidic aqueous medium comprises an aqueous solution of an acid salt, a monobasic acid, or a mixture of monobasic acids.
Claim 23
Dependent Claim
23 words
The process of claim 1 wherein the acidic aqueous medium comprises an aqueous solution of nitric acid and a decomposable monobasic organic acid.
Claim 24
Dependent Claim
17 words
The process of claim 22 wherein the organic acid is acetic acid, formic acid, or mixtures thereof.
Claim 25
Dependent Claim
28 words
The process of claim 1 wherein the slurry contains about 24 to about 32 weight percent alumina and has a viscosity of about 800 to about 1200 cps.
Claim 26
Dependent Claim
22 words
The process of claim 1 wherein the ammonia concentration in the water-immiscible liquid is between about 0.01 to about 1.0 weight percent.
Claim 27
Dependent Claim
22 words
The process of claim 1 wherein the ammonia concentration in the water-immiscible liquid is between about 0.04 to about 0.07 weight percent.
Claim 28
Dependent Claim
41 words
The process of claim 1 wherein water-immiscible liquid and ammonia are introduced into the lower portion of the upper body, flow upwardly through the body in countercurrent flow with the droplets, and are removed at the top of the upper body.
References Cited (Backward Citations)
US3173883A
Cited
US3257163A
Cited
US3558508A
Cited
US4006103A
Cited
US3960772A
Cited
US4003851A
Cited
US3979334A
Cited
US4051073A
Cited
US4154812A
Cited
US4116882A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-12-17 | 1983-06-18 | 1983-12-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-12-17 | 1987-06-18 | 1987-12-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-12-17 | 1991-06-18 | 1991-12-18 | $7700.00 | Window Closed / Lapsed |