US4806665A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of silica sol
Assignee: ChampionX LLC
•
Filing: 1987-11-05
•
Granted: 1989-02-21
•
Expires: 2007-11-05
Abstract
Abstract A method for producing a silica sol containing less than 200 ppm sodium having an average particle size of 2-110 nm, and a particle size distribution with a coefficient dispersion of 0.16-0.4. The silica sols are produced using a lower alkanolamine containing heal to which aliquots of silicic acid are added. The aliquots are added to maintain a substantially constant concentration of colloidal silica in the product. Subsequent to production, the sol may be concentrated by ultrafiltration. Preparation of low sodium silica sol utilizing a constant silica technique by heating the initial heel to 94°±4° C. and adding additional silica maintaining constant total silica. The stabilization is effected with an alkanolamine.
Inventors
- 👤 Robert D. Jones
- 👤 Curran M. Simpson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 20:28
CPC Classifications
C; C01; C01B; C01B33/00; C01B33/113; C01B33/12; C01B33/14; C01B33/146; C01B33/148; C01B33/145; C01B33/1465
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
168 words
A low sodium aqueous silica sol containing no more than 150 ppm of an alkali metal, and having a silica concentration of 5-55 weight % SiO 2 ; said colloidal silica having a particle size greater than 2 nm; produced by a method comprising the steps of: A. providing a 0.1%-5% aqueous solution of a lower alkanol amine; B. heating the aqueous solution of the lower alkanol amine to at least 80° C., but less than reflux temperatures; C. adding to the heated aqueous solution of the lower alkanol amine a 2 to 10% by weight aqueous solution of silicic acid in a volume ratio of from 2:1 to 15:1, the mole ratio of SiO 2 to lower alkanol amine being in the range of 1:1 to 150:1; and D. concentrating the dilute aqueous sol by either distillation or ultrafiltration so as to recover an aqueous colloidal silica sol which contains 5-55% by weight SiO 2 having pH of 8-10.5 and containing less than 150 ppm alkali metal.
Claim 2
Dependent Claim
168 words
A low sodium aqueous silica sol containing no more than 150 ppm of an alkali metal, and having a silica concentration of 5-55 weight % SiO 2 ; said colloidal silica having a particle size greater than 2 nm; produced by a method comprising the steps of: A. providing a 0.1%-5% aqueous solution of a lower alkanol amine; B. heating the aqueous solution of the lower alkanol amine to at least 80° C., but less than reflux temperatures; C. adding to the heated aqueous solution of the lower alkanol amine a 2 to 10% by weight aqueous solution of silicic acid in a volume ratio of from 2:1 to 15:1, the mole ratio of SiO 2 to lower alkanol amine being in the range of 1:1 to 150:1; and D. concentrating the dilute aqueous sol by either distillation or ultrafiltration so as to recover an aqueous colloidal silica sol which contains 5-55% by weight SiO 2 having pH of 8-10.5 and containing less than 150 ppm alkali metal.
Claim 3
Dependent Claim
138 words
A method of producing the low sodium silica sol of claim 1 comprising the steps of: A. providing a 0,.1%-5% aqueous solution of a lower alkanol amine; B. heating the aqueous solution of the lower alkanol amine to at least 80° C., but less than reflux temperatures; C. Adding to the heated aqueous solution of the lower alkanol amine a 2 to 10% by weight aqueous solution of silicic acid in a volume ratio of from 2:1 to 15:1, the mole ratio of SiO 2 to lower alkanol amine being in the range of 1:1 to 150:1; and D. Concentrating the dilute aqueous sol by either distillation or ultrafiltration so as to recover an aqueous colloidal silica sol which contains 5-55% by weight SiO 2 having a pH of 8-10.5 and containing less than 150 ppm alkali metal.
Claim 4
Dependent Claim
33 words
The process of claim 2 wherein the heel is composed of a lower alkanolamine and silicic acid such that the ratio of SiO 2 to lower alkanol amine ratio is 1:1 to 50:1.
Claim 5
Dependent Claim
10 words
The method of claim 3 wherein said alkanolamine is monoethanolamine.
Claim 6
Dependent Claim
11 words
The method of claim 3 wherein the lower alkanolamine is diethanolamine.
Claim 7
Dependent Claim
10 words
The method of claim 3 wherein the alkanolamine is aminoethylethanolamine.
Claim 8
Dependent Claim
167 words
A low sodium aqueous silica sol containing no more than 130 ppm of an alkali metal, and having a silica concentration of 5-55 weight % SiO 2 ; said colloidal silica having a particle size greater than 2 nm; produced by a method comprising the steps of: A. providing a 0.1%-5% aqueous solution of a lower alkanol amine; B. heating the aqueous solution of the lower alkanol amine to at least 80° C., but less than reflux temperatures; C. adding to the heated aqueous solution of the lower alkanol amine a 2 to 10% by weight aqueous solution of silicic acid in a volume ratio of from 2:1 to 15:1, the mole ratio of SiO 2 to lower alkanol amine being in the range of 1:1 to 150:1; and D. concentrating the dilute aqueous sol by either distillation or ultrafiltration so as to recover an aqueous colloidal slica sol which contains 5-55% by weight SiO 2 having pH of 8-10.5 and containing less than 130/ppm alkali metal.
Claim 9
Dependent Claim
167 words
A low sodium aqueous silica sol containing no more than 130 ppm of an alkali metal, and having a silica concentration of 5-55 weight % SiO 2 ; said colloidal silica having a particle size greater than 2 nm; produced by a method comprising the steps of: A. providing a 0.1%-5% aqueous solution of a lower alkanol amine; B. heating the aqueous solution of the lower alkanol amine to at least 80° C., but less than reflux temperatures; C. adding to the heated aqueous solution of the lower alkanol amine a 2 to 10% by weight aqueous solution of silicic acid in a volume ratio of from 2:1 to 15:1, the mole ratio of SiO 2 to lower alkanol amine being in the range of 1:1 to 150:1; and D. concentrating the dilute aqueous sol by either distillation or ultrafiltration so as to recover an aqueous colloidal slica sol which contains 5-55% by weight SiO 2 having pH of 8-10.5 and containing less than 130/ppm alkali metal.
References Cited (Backward Citations)
US29948A
Cited
US2408654A
Cited
US2689245A
Cited
US3239549A
Cited
US3239521A
Cited
US3301853A
Cited
US3129177A
Cited
US3326910A
Cited
USRE29948E
Cited
US4376757A
Cited
US4644077A
Cited
US4694092A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-02-21 | 1992-08-22 | 1993-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-21 | 1996-08-22 | 1997-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-21 | 2000-08-22 | 2001-02-21 | $7700.00 | Window Closed / Lapsed |