Patent US4094771A successfully refreshed from Google Patents.
US4094771A
Expired / Lapsed
US
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Process for preparation of a sprayable precipitated silicic acid suspension
Assignee: Evonik Operations GmbH
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Filing: 1976-01-13
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Granted: 1978-06-13
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Expires: 1996-01-13
Abstract
Abstract A silicic acid filter cake and suspension agent are fed to a container equipped with a stirrer having a peripheral speed of about 20-30 m/sec. The ratio of container diameter to stirrer diameter is about 3:1. The ratio of container diameter to level of filling is at most about 1:2. The container contains at least about 1.5 to about 2 kg of silicic acid suspension, for each 1 kg of silicic acid filter cake which is added to the container. The contents of the container is mixed while maintaining a pH of at most about 4. A portion of the resulting silicic acid suspension is drawn off from the zone of highest turbulence in the container.
Inventors
- 👤 Bernd Brandt
- 👤 Peter Nauroth
- 👤 Albert Peters
- 👤 Helmut Reinhardt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 03:39
CPC Classifications
C; C01; C01B; C01B33/00; C01B33/113; C01B33/12; C01B33/14; C01B33/141; C01B33/1415; C01B33/1417; C09; C09C; C09C1/00; C09C1/28; C09C1/30; C01P; C01P2004/00; C01P2004/60; C01P2004/61; C01P2006/00; C01P2006/22
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
192 words
Process for the production of a sprayable, highly concentrated, aqueous suspension of a precipitated silicic acid, said suspension having little grit and at least about 18 percent by weight solids, said process comprising: (a) continuously feeding a silicic acid filter cake and a suspension agent into a dissolver container provided with stirring means; (b) stirring said filter cake and suspension agent while maintaining a maximum pH value of about 4 in the suspension, said stirring means having a peripheral speed of about 20-30 m/sec; and (c) continuously removing a portion of the resulting suspension from a zone of highest turbulence of the suspension in said container; wherein said container and said stirring means each have a diameter and the ratio of container diameter to the diameter of the stirring means is about 3:1 and the ratio of container diameter to level of filling of said container is maintained at a maximum of about 1:2; and further wherein the silicic acid suspension in said container is maintained in an amount of at least 1.5 to about 2 kg. for each 1 kg of silicic acid filter cake which is added to the container.
Claim 2
Dependent Claim
192 words
Process for the production of a sprayable, highly concentrated, aqueous suspension of a precipitated silicic acid, said suspension having little grit and at least about 18 percent by weight solids, said process comprising: (a) continuously feeding a silicic acid filter cake and a suspension agent into a dissolver container provided with stirring means; (b) stirring said filter cake and suspension agent while maintaining a maximum pH value of about 4 in the suspension, said stirring means having a peripheral speed of about 20-30 m/sec; and (c) continuously removing a portion of the resulting suspension from a zone of highest turbulence of the suspension in said container; wherein said container and said stirring means each have a diameter and the ratio of container diameter to the diameter of the stirring means is about 3:1 and the ratio of container diameter to level of filling of said container is maintained at a maximum of about 1:2; and further wherein the silicic acid suspension in said container is maintained in an amount of at least 1.5 to about 2 kg. for each 1 kg of silicic acid filter cake which is added to the container.
Claim 3
Dependent Claim
21 words
Process as claimed in claim 1 wherein said filter cake is fed to said container via a single screw feeding means.
Claim 4
Dependent Claim
21 words
Process as claimed in claim 1 wherein said filter cake is fed to said container via a double screw feeding means.
Claim 5
Dependent Claim
13 words
Process as claimed in claim 1 wherein said suspension agent is an acid.
Claim 6
Dependent Claim
15 words
Process as claimed in claim 4 wherein said acid is a dilute, aqueous mineral acid.
Claim 7
Dependent Claim
28 words
Process as claimed in claim 5 wherein said acid is an aqueous sulphuric acid solution having a concentration of about 20 to about 30% by weight sulphuric acid.
Claim 8
Dependent Claim
25 words
Process as claimed in claim 1 wherein said silicic acid filter cake and said suspension agent are simultaneously fed to said container via feeding means.
Claim 9
Dependent Claim
23 words
Process as claimed in claim 1 wherein the ratio of the container diameter to the diameter of the stirring means is about 2.5:1.
Claim 10
Dependent Claim
23 words
Process as claimed in claim 1 wherein the ratio of container diameter to the level of filling of said container is about 1:1.
Claim 11
Dependent Claim
22 words
Process as claimed in claim 8 wherein the ratio of container diameter to level of filling of said container is about 1:1.
Claim 12
Dependent Claim
16 words
Process as claimed in claim 1 wherein said stirring means is a rotatable double disc agitator.
Claim 13
Dependent Claim
16 words
Process as claimed in claim 10 wherein said stirring means is a rotatable double disc agitator.
Claim 14
Dependent Claim
19 words
Process as claimed in claim 1 wherein said resulting suspension is removed from said container via a filter basket.
Claim 15
Dependent Claim
19 words
Process as claimed in claim 12 wherein said resulting suspension is removed from said container via a filter basket.
Claim 16
Dependent Claim
23 words
Process as claimed in claim 1 wherein said resulting suspension is removed from said container by means of a series connected compulsory mixer.
Claim 17
Dependent Claim
23 words
Process as claimed in claim 1 wherein said resulting suspension is removed from said container by way of a series connected mixing pump.
Claim 18
Dependent Claim
24 words
Process as claimed in claim 1 wherein a portion of said resulting suspension that is removed from said container is returned to said container.
Claim 19
Dependent Claim
43 words
Process as claimed in claim 1 in which said silicic acid filter cake contains about 20 percent by weight solids and said sprayable, highly concentrated aqueous suspension of said precipitated silicic acid has a solid content of at least about 25 weight percent.
References Cited (Backward Citations)
US3172727A
Cited
CA580279A
Cited
US1739305A
Cited
US1939178A
Cited
US2663553A
Cited
FR1215038A
Cited
US3051454A
Cited
US3256068A
Cited
US3326815A
Cited
US3372046A
Cited
US3308991A
Cited
US3647397A
Cited
US3957253A
Cited
DE2401217A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-06-12 | 1981-12-12 | 1982-06-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-06-12 | 1985-12-12 | 1986-06-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-06-12 | 1989-12-12 | 1990-06-13 | $7700.00 | Window Closed / Lapsed |