US3784456A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus and method for purifying alkali metal hydroxide solutions
Assignee: PPG Industries Inc
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Filing: 1972-03-02
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Granted: 1974-01-08
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Expires: 1992-03-02
Abstract
Abstract Aqueous alkali metal hydroxide solutions are purified by passage through a porous cathode of an electrolytic cell having an anode located downstream of the cathode. An electrolytic cell of special construction particularly useful is described.
Inventors
- 👤 J Otto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 20:42
CPC Classifications
C; C01; C01D; C01D1/00; C01D1/04; C01D1/28; C01D1/40; C25; C25B; C25B9/00; C25B9/17
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
13 words
The method of claim 1 wherein the alkali metal hydroxide is sodium hydroxide.
Claim 2
Independent Claim
102 words
A method of removing metal ion impurities from aqueous alkali metal hydroxide solution which comprises passing metal ion contaminated, substantially oxygen free, alkali metal hydroxide solution through the pores of and in intimate contact with porous walls of a hollow cylindrical porous cathode having an anode located within its walls while subjecting the solution to electrolysis in the substantial absence of oxygen to deposit out the metal ion contamination in the pores of the cathode wall, and thereafter removing the solution from the cell by direcTly withdrawing it from within the hollow cathode without further contact with any electrodes within the cell.
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) | 1977-01-07 | 1977-07-09 | 1978-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-07 | 1981-07-09 | 1982-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-07 | 1985-07-09 | 1986-01-08 | $7700.00 | Window Closed / Lapsed |