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US5236680A
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Preparation of amorphous silica-alumina particles by acid-treating spherical P-type zeolite particles crystallized from a sodium aluminosilicate gel
Assignee: Mizusawa Industrial Chemicals Ltd
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Filing: 1991-06-18
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Granted: 1993-08-17
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Expires: 2011-06-18
Abstract
Abstract The invention is a process for preparing amorphous silica alumina spherical particles by mixing sodium silicate or silicic acid gel with sodium aluminate and sodium hydroxide in an aqueous solution to form a gel, homogenizing the formed gel, crystallizing this intermediate product at 85 DEG C. to 200 DEG under atmospheric pressure or under hydrothermal conditions to form spherical zeolite particles with an x-ray diffraction pattern inherent to P-type zeolites and with a notched surface, treating the zeolite particles with acid to remove the sodium, thereby rendering the particles amorphous.
Inventors
- 👤 Tadahisa Nakazawa
- 👤 Masahide Ogawa
- 👤 Kiyoshi Abe
- 👤 Kazuhiko Suzuki
- 👤 Takashi Tokita
- 👤 Toshio Ito
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 17:17
CPC Classifications
A; A61; A61K; A61K8/00; A61K8/18; A61K8/19; A61K8/26; A61K8/25; A61Q; A61Q1/00; A61Q1/02; C; C01; C01B; C01B33/00; C01B33/113; C01B33/12; C01B33/18; C01B33/187; C01B39/00; C01B39/02; C01B39/28; C08; C08K; C08K7/00; C08K7/16; C08K7/18; C09; C09C; C09C1/00; C09C1/28; C09C1/30; C09C1/40; C09C1/405; C10; C10M; C10M171/00; C10M171/001; A61K2800/00; A61K2800/40; A61K2800/42; A61K2800/43; C01P; C01P2002/00; C01P2002/02; C01P2002/70; C01P2002/72; C01P2002/80; C01P2002/82; C01P2004/00; C01P2004/01; C01P2004/03; C01P2004/30; C01P2004/32; C01P2004/50; C01P2004/51; C01P2004/52; C01P2004/60; C01P2004/61; C01P2004/62; C01P2004/80; C01P2004/82; C01P2006/00; C01P2006/10; C01P2006/11; C01P2006/12; C01P2006/19; C01P2006/60; C01P2006/80; C01P2006/82; C01P2006/90
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
147 words
A process for the preparation of amorphous silica-alumina spherical particles, which comprises the steps of: (a) mixing sodium silicate or active silicic acid gel, sodium aluminate and sodium hydroxide in aqueous solution in the component molar ratios of: Na 2 O/SiO 2 =0.2 to 8; SiO 2 /Al 2 O 3 =3 to 20; and H 2 O/Na 2 O=20 to 200, to form a gel of sodium aluminosilicate; (b) homogenizing the gel obtained in step (a) and effecting crystallization at a temperature of 85° to 200° C. under atmospheric pressure or under hydrothermal conditions to form zeolite particles having an X-ray diffraction pattern inherent to P type zeolite, individual particles having a definite spherical shape as a whole and a notched surface; and (c) subjecting the zeolite particles to a one-staged or multi-staged acid treatment to remove the sodium component sufficiently to render the particles amorphous.
Claim 2
Dependent Claim
147 words
A process for the preparation of amorphous silica-alumina spherical particles, which comprises the steps of: (a) mixing sodium silicate or active silicic acid gel, sodium aluminate and sodium hydroxide in aqueous solution in the component molar ratios of: Na 2 O/SiO 2 =0.2 to 8; SiO 2 /Al 2 O 3 =3 to 20; and H 2 O/Na 2 O=20 to 200, to form a gel of sodium aluminosilicate; (b) homogenizing the gel obtained in step (a) and effecting crystallization at a temperature of 85° to 200° C. under atmospheric pressure or under hydrothermal conditions to form zeolite particles having an X-ray diffraction pattern inherent to P type zeolite, individual particles having a definite spherical shape as a whole and a notched surface; and (c) subjecting the zeolite particles to a one-staged or multi-staged acid treatment to remove the sodium component sufficiently to render the particles amorphous.
Claim 3
Dependent Claim
40 words
The process according to claim 1, wherein the component molar ratios used in step (a) are Na 2 O/SiO 2 =0.5 to 2.0, SiO 2 /Al 2 O 3 =4 to 10, and H 2 O/Na 2 O=30 to 100.
Claim 4
Dependent Claim
39 words
The process according to claim 1, wherein the acid treatment in step (c) is conducted by forming an aqueous slurry of the zeolite particles and adding an acid to the slurry to bring the pH between 2.0 and 7.0.
Claim 5
Dependent Claim
15 words
The process according to claim 3, wherein the pH value is from 3.5 to 7.0.
Claim 6
Dependent Claim
22 words
The process according to claim 3, wherein the concentration of the zeolite particles in the slurry is 5 to 30% by weight.
Claim 7
Dependent Claim
24 words
The process according to claim 3, wherein the acid treatment is step (c) is conducted at a temperature of from 20° to 100° C.
Claim 8
Dependent Claim
22 words
The process according to claim 1, wherein in step (c) the one-stage acid treatment is conducted to remove only the sodium component.
Claim 9
Dependent Claim
23 words
The process according to claim 1, wherein in step (c) the multi-staged acid treatment is conducted to remove the sodium and alumina components.
Claim 10
Dependent Claim
27 words
The process according to claim 8, wherein the multi-staged acid treatment comprises a first acid treatment, a intervening drying or calcining treatment, and a second acid treatment.
Claim 11
Dependent Claim
158 words
The process according to claim 1, wherein the amorphous silica or silica-alumina spherical particles have a definite spherical shape and a notched surface, the circularity (A) represented by the following formula: ##EQU5## wherein r1 stands for the radius of the circumcircle of the profile of the particle in an electron microscope photo thereof and r2 stands for the radius of the inscribed circle of the profile of the particle in the electron microscope photo, is in the range of from 0.9 to 1, the notching degree (B) represented by the following formula: ##EQU6## wherein Δt stands for the depth between the peak and trough in the radial direction of notches on the profile of the particle in the electron microscope photo and r1 is as defined above, is in the range of from 1 to 10%, and the primary particle size (2r1) determined by the electron microscope method is in the range of from 0.1 to 20 μm.
Claim 12
Dependent Claim
48 words
The process according to claim 10, wherein the spherical particles comprise 60 to 99.99% by weight of SiO 2 , 0 to 15% by weight of Al 2 O 3 , 0 to 4% by weight of Na 2 O and less than 15% of the ignition loss.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-08-16 | 1997-02-15 | 1997-08-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-08-16 | 2001-02-15 | 2001-08-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-08-16 | 2005-02-15 | 2005-08-17 | $7700.00 | Window Closed / Lapsed |