US4640807A
Expired / Lapsed
US
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Process for the preparation of silica spheres
Assignee: Shell USA Inc
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Filing: 1985-07-24
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Granted: 1987-02-03
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Expires: 2005-07-24
Abstract
Abstract Silica spheres are prepared in a process comprising: (a) preparing a silica hydrosol by mixing an aqueous solution of an alkali metal silicate with an aqueous solution of an acid; (b) converting the hydrosol into droplet form; (c) aging the droplets in a fluid to produce hydrogel particles; (d) partially drying the hydrogel particles at 10° to 60° C. in air having a relative humidity in the range of from 45 to 95%, to a water content in the range of from 0.3 to 1.3 kg/kg solids; (e) decreasing the cation content of the hydrogel particles by ion-exchange in an aqueous medium to less than 10% w, calculated on dry material; and (f) finally drying the hydrogel particles to obtain silica spheres.
Inventors
- 👤 Madjid Afghan
- 👤 Josephus G. Sponselee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:56
CPC Classifications
C; C01; C01B; C01B33/00; C01B33/113; C01B33/12; C01B33/14; C01B33/152; C01B33/154; C01B33/1546; B; B01; B01J; B01J21/00; B01J21/06; B01J21/08
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
123 words
A process for the preparation of silica spheres which comprises: (a) preparing a silica hydrosol by mixing an aqueous solution of an alkali metal silicate with an aqueous solution of an acid; (b) converting the hydrosol into droplet form; (c) aging the droplets in a fluid to produce hydrogel particles; (d) partially drying the hydrogel particles at 10° to 60° C. in air having a relative humidity in the range of from 45 to 95%, to a water content in the range of from 0.3 to 1.3 kg/kg solids; (e) decreasing the cation content of the hydrogel particles by ion-exchange in an aqueous medium to less than 10%w, calculated on dry material; and (f) finally drying the hydrogel particles to obtain silica spheres.
Claim 2
Dependent Claim
123 words
A process for the preparation of silica spheres which comprises: (a) preparing a silica hydrosol by mixing an aqueous solution of an alkali metal silicate with an aqueous solution of an acid; (b) converting the hydrosol into droplet form; (c) aging the droplets in a fluid to produce hydrogel particles; (d) partially drying the hydrogel particles at 10° to 60° C. in air having a relative humidity in the range of from 45 to 95%, to a water content in the range of from 0.3 to 1.3 kg/kg solids; (e) decreasing the cation content of the hydrogel particles by ion-exchange in an aqueous medium to less than 10%w, calculated on dry material; and (f) finally drying the hydrogel particles to obtain silica spheres.
Claim 3
Dependent Claim
23 words
The process of claim 1 wherein the hydrogel particles are partially dried to a water content of from 0.45 to 0.95 kg/kg solids.
Claim 4
Dependent Claim
31 words
The process of claim 1 wherein the hydrogel particles are partially dried at 15° to 40° C. in air having a relative humidity in the range of from 60 to 95%.
Claim 5
Dependent Claim
38 words
The process of claim 1 wherein prior to step (d), the hydrogel particles are partially dried with air having a relative humidity below 45% to a water content in the range of from 1.4 to 3.5 kg/kg solids.
Claim 6
Dependent Claim
24 words
The process of claim 4 wherein the hydrogel particles are partially dried at a temperature in the range of from 60° to 120° C.
Claim 7
Dependent Claim
25 words
The process of claim 1 wherein the fluid in which the droplets are aged is air or a liquid which is not miscible with water.
Claim 8
Dependent Claim
25 words
The process of claim 1 wherein the hydrogel particles, after partially drying them and before decreasing their cation content, are subjected to a hydrothermal treatment.
Claim 9
Dependent Claim
37 words
The process of claim 7 wherein the hydrothermal treatment is carried out by submerging the hydrogel particles in a quantity of liquid water at least equal in volume to that of the hydrogel particles to be treated.
Claim 10
Dependent Claim
24 words
The process of claim 7 wherein the hydrothermal treatment is carried out at a temperature in the range of from 80° to 350° C.
Claim 11
Dependent Claim
22 words
The process of claim 9 wherein the temperature of the hydrothermal treatment is in the range of from 100° to 300° C.
Claim 12
Dependent Claim
23 words
The process of claim 1 wherein the cation content of the hydrogel particles is decreased to less than 7%w, calculated on dry material.
Claim 13
Dependent Claim
19 words
The process of claim 11 wherein the cation content is decreased to less than 1%w, calculated on dry material.
Claim 14
Dependent Claim
24 words
The process of claim 1 wherein the silica spheres obtained in step (f) after finally drying the hydrogel particles, are subjected to a calcination.
Claim 15
Dependent Claim
18 words
The process of claim 13 wherein the calcination is carried out at a temperature up to 1000° C.
Claim 16
Dependent Claim
21 words
The process of claim 14 wherein the temperature of the calcination is in the range of from 800° to 950° C.
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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) | 1990-02-02 | 1990-08-04 | 1991-02-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-02 | 1994-08-04 | 1995-02-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-02 | 1998-08-04 | 1999-02-03 | $7700.00 | Window Closed / Lapsed |