US4256682A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of preparing silica gel pellets
Assignee: WR Grace and Co Conn
•
Filing: 1980-03-05
•
Granted: 1981-03-17
•
Expires: 2000-03-05
Abstract
Abstract Silica gel pellets are prepared by mixing finely divided silica gel with an aqueous ammoniacal medium, compressing the mixture into pellets, and drying the pellets.
Inventors
- 👤 Dean A. Denton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 06:20
CPC Classifications
B; B01; B01J; B01J21/00; B01J21/06; B01J21/08; B01J2/00; B01J2/22
Claims Analysis
Total Claims: 47
Claim 1
Independent Claim
36 words
A method of preparing silica gel pellets comprising mixing a finely divided silica gel with an aqueous ammoniacal medium in amounts sufficient to provide a moldable mixture, compressing the mixture into pellets, and drying the pellets.
Claim 2
Independent Claim
36 words
A method of preparing silica gel pellets comprising mixing a finely divided silica gel with an aqueous ammoniacal medium in amounts sufficient to provide a moldable mixture, compressing the mixture into pellets, and drying the pellets.
Claim 3
Dependent Claim
33 words
The method of claim 1 in which from about 0.35 to about 0.55 parts by weight of the aqueous ammoniacal medium are mixed with about one part by weight of the silica gel.
Claim 4
Dependent Claim
22 words
The method of claim 1 in which the silica gel has a weight median particle diameter of less than about 500 microns.
Claim 5
Dependent Claim
24 words
The method of claim 1 in which the silica gel has a weight median particle diameter of from about 75 to about 250 microns.
Claim 6
Dependent Claim
23 words
The method of claim 1 in which the silica gel has a pore volume of at least about 0.9 cubic centimeters per gram.
Claim 7
Dependent Claim
23 words
The method of claim 1 in which the silica gel has a water content of from about 1 to about 15 weight percent.
Claim 8
Dependent Claim
14 words
The method of claim 1 in which the silica gel is a silica aerogel.
Claim 9
Dependent Claim
14 words
The method of claim 1 in which the silica gel is a silica xerogel.
Claim 10
Dependent Claim
16 words
The method of claim 1 in which the silica gel is an intermediate density silica xerogel.
Claim 11
Dependent Claim
23 words
The method of claim 1 in which the silica gel has an average pore diameter of from about 80 to about 200 angstroms.
Claim 12
Dependent Claim
25 words
The method of claim 1 in which the silica gel has a surface area of from about 250 to about 400 square meters per gram.
Claim 13
Dependent Claim
26 words
The method of claim 1 in which the silica gel has a packed bulk density of from about 0.30 to about 0.50 grams per cubic centimeter.
Claim 14
Dependent Claim
27 words
The method of claim 1 in which the silica gel has a pH of from about 7 to about 10 prior to contact with the ammoniacal medium.
Claim 15
Dependent Claim
21 words
The method of claim 1 in which the aqueous ammoniacal medium has a pH of from about 10 to about 14.
Claim 16
Dependent Claim
16 words
The method of claim 1 in which the aqueous ammoniacal medium comprises an ammonium hydroxide solution.
Claim 17
Dependent Claim
19 words
The method of claim 15 in which the solution contains from about 20 to about 30 weight percent ammonia.
Claim 18
Dependent Claim
23 words
The method of claim 1 in which the mixture is compressed under a pressure of at least about 1000 pounds per square inch.
Claim 19
Dependent Claim
25 words
The method of claim 1 in which the mixture is compressed under a pressure of from about 2,000 to about 10,000 pounds per square inch.
Claim 20
Dependent Claim
15 words
The method of claim 1 in which the mixture is compressed in a rotary press.
Claim 21
Dependent Claim
16 words
The method of claim 1 in which the mixture is compressed to form solid, cylindrical pellets.
Claim 22
Dependent Claim
30 words
The method of claim 1 in which the pellets are dried at a temperature of from about 90° to about 250° C. for from about 1/2 to about 6 hours.
Claim 23
Dependent Claim
10 words
The method of claim 1 further comprising calcining the pellets.
Claim 24
Dependent Claim
13 words
The method of claim 22 in which the mixture further comprises a lubricant.
Claim 25
Dependent Claim
28 words
The method of claim 23 in which the pellets are calcined at a temperature of at least about 538° C. for from about 1/2 to about 4 hours.
Claim 26
Dependent Claim
19 words
The method of claim 1 further comprising aging the pellets for at least about 1 hour prior to drying.
Claim 27
Dependent Claim
19 words
The method of claim 25 in which the pellets are aged for from about 24 to about 175 hours.
Claim 28
Independent Claim
80 words
A method of preparing silica gel pellets comprising mixing from about 0.35 to about 0.55 parts by weight of an ammonium hydroxide solution having a pH of from about 10 to about 14 and about 1 part by weight of an intermediate density silica xerogel having a weight median particle diameter of less than about 500 microns, compressing the mixture into solid cylindrical pellets under a pressure of at least about 1000 pounds per square inch, and drying the pellets.
Claim 29
Independent Claim
80 words
A method of preparing silica gel pellets comprising mixing from about 0.35 to about 0.55 parts by weight of an ammonium hydroxide solution having a pH of from about 10 to about 14 and about 1 part by weight of an intermediate density silica xerogel having a weight median particle diameter of less than about 500 microns, compressing the mixture into solid cylindrical pellets under a pressure of at least about 1000 pounds per square inch, and drying the pellets.
Claim 30
Dependent Claim
24 words
The method of claim 27 in which the silica xerogel has a weight median particle diameter of from about 75 to about 250 microns.
Claim 31
Dependent Claim
23 words
The method of claim 27 in which the silica xerogel has a pore volume of at least about 0.9 cubic centimeters per gram.
Claim 32
Dependent Claim
23 words
The method of claim 27 in which the silica xerogel has an average pore diameter of from about 80 to about 200 angstroms.
Claim 33
Dependent Claim
25 words
The method of claim 27 in which the silica xerogel has a surface area of from about 250 to about 400 square meters per gram.
Claim 34
Dependent Claim
26 words
The method of claim 27 in which the silica xerogel has a packed bulk density of from about 0.30 to about 0.50 grams per cubic centimeter.
Claim 35
Dependent Claim
27 words
The method of claim 27 in which the silica xerogel has a pH of from about 7 to about 10 prior to contact with the ammoniacal medium.
Claim 36
Dependent Claim
19 words
The method of claim 27 in which the solution contains from about 20 to about 30 weight percent ammonia.
Claim 37
Dependent Claim
25 words
The method of claim 27 in which the mixture is compressed under a pressure of from about 2,000 to about 10,000 pounds per square inch.
Claim 38
Dependent Claim
15 words
The method of claim 27 in which the mixture is compressed in a rotary press.
Claim 39
Dependent Claim
30 words
The method of claim 27 in which the pellets are dried at a temperature of from about 90° to about 250° C. for from about 1/2 to about 6 hours.
Claim 40
Dependent Claim
10 words
The method of claim 27 further comprising calcining the pellets.
Claim 41
Dependent Claim
13 words
The method of claim 38 in which the mixture further comprises a lubricant.
Claim 42
Dependent Claim
27 words
The method of claim 39 in which the pellets are calcined at a temperature of at least about 538° C. for about 1/2 to about 4 hours.
Claim 43
Dependent Claim
19 words
The method of claim 27 further comprising aging the pellets for at least about 1 hour prior to drying.
Claim 44
Dependent Claim
19 words
The method of claim 41 in which the pellets are aged for from about 24 to about 175 hours.
Claim 45
Dependent Claim
33 words
The method of claim 1 in which from about 0.20 to about 0.65 parts by weight of the aqueous ammoniacal medium are mixed with about one part by weight of the silica gel.
Claim 46
Dependent Claim
25 words
The method of claim 1 in which the silica gel has a pore volume of from about 0.9 to about 1.3 cubic centimeters per gram.
Claim 47
Dependent Claim
25 words
The method of claim 27 in which the silica xerogel has a pore volume of from about 0.9 to about 1.3 cubic centimeters per gram.
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) | 1984-03-16 | 1984-09-15 | 1985-03-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-16 | 1988-09-15 | 1989-03-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-16 | 1992-09-15 | 1993-03-17 | $7700.00 | Window Closed / Lapsed |