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US3668088A
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Method of producing colloidal silica by electrodialysis of a silicate
Assignee: EIDP Inc
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Filing: 1969-12-02
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Granted: 1972-06-06
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Expires: 1989-12-02
Abstract
Abstract Silica sol is made by electrodialysis of a solelectrolyte containing an aqueous silica sol, aqueous sodium or potassium silicate, and a supplementary electrolyte such as sodium or potassium carbonate or sulfate. Temperature is maintained at 50* to 100* C. A source of non-siliceous anion is added as needed to maintain normality of the supplementary electrolyte between 0.01 and 0.15, and silicate is added as necessary to maintain pH between 8.0 and 9.5. After the electrodialysis, most of the sodium ions and the anions of the supplementary electrolyte are removed by treatment with ion exchange resins, then the sol is concentrated to 30 or 40 percent silica.
Inventors
- 👤 Ralph K Iler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 19:16
CPC Classifications
B; B01; B01D; B01D61/00; B01D61/42; B01D61/44; C; C01; C01B; C01B33/00; C01B33/113; C01B33/12; C01B33/14; C01B33/141; B01D2311/00; B01D2311/04
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
25 words
Process of claim 1 wherein the sUpplementary electrolyte is a member of the group consisting of sodium sulfate, sodium carbonate, potassium sulfate and potassium carbonate.
Claim 2
Dependent Claim
39 words
Process of claim 1 wherein the temperature and pH of the sol-electrolyte are maintained at about 80* C. and 9, respectively, and the normality of the supplementary electrolyte in the catholyte is maintained at about 0.03 to 0.08 normal.
Claim 3
Dependent Claim
19 words
Process of claim 3 wherein the sol-electrolyte is composed of aqueous silica, sodium silicate, and sodium sulfate or carbonate.
References Cited (Backward Citations)
US2244325A
Cited
US2577485A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-06 | 1975-12-06 | 1976-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-06 | 1979-12-06 | 1980-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-06 | 1983-12-06 | 1984-06-06 | $7700.00 | Window Closed / Lapsed |