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US4173526A
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Chlor-alkali cell diaphragm and its treatment
Assignee: EIDP Inc
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Filing: 1978-11-21
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Granted: 1979-11-06
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Expires: 1998-11-21
Abstract
Abstract Magnesium compounds are added to chlor-alkali cell asbestos diaphragms, either initially or after some use, to improve electrical operating characteristics.
Inventors
- 👤 James C. Fang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 05:38
CPC Classifications
C; C25; C25B; C25B13/00; C25B13/04; C25B1/00; C25B1/01; C25B1/34; C25B1/46; C25B13/05; C25B13/06; C25B13/07
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
55 words
A diaphragm for a chlor-alkali cell comprising asbestos and at least one magnesium compound selected from magnesium oxide, hydroxide, carbonate, oxyhalide and hydroxyhalide (wherein the halide is at least one of fluorine and chlorine), the magnesium compound being present in an amount of about 5-50% by weight based on the asbestos plus the magnesium compound.
Claim 2
Dependent Claim
55 words
A diaphragm for a chlor-alkali cell comprising asbestos and at least one magnesium compound selected from magnesium oxide, hydroxide, carbonate, oxyhalide and hydroxyhalide (wherein the halide is at least one of fluorine and chlorine), the magnesium compound being present in an amount of about 5-50% by weight based on the asbestos plus the magnesium compound.
Claim 3
Dependent Claim
27 words
The diaphragm of claim 1 wherein the magnesium compound is present in an amount of about 35-45% by weight based on the asbestos plus the mangesium compound.
Claim 4
Dependent Claim
24 words
The diaphragm of claim 1 wherein the magnesium compound is magnesium oxide having an average particle size about in the range of 1.0-2.0 μm.
Claim 5
Dependent Claim
11 words
The diaphragm of claim 1 which also contains a fluoropoylmer binder.
Claim 6
Dependent Claim
48 words
A process for treating a chlor-alkali cell diaphragm which comprises passing through the diaphragm a slurry containing a magnesium compound selected from magnesium oxide, hydroxide, carbonate, oxyhalide and hydroxyhalide (wherein the halide is at least one of fluorine and chlorine), and depositing such magnesium compound within the diaphragm.
Claim 7
Dependent Claim
48 words
A process for treating a chlor-alkali cell diaphragm which comprises passing through the diaphragm a slurry containing a magnesium compound selected from magnesium oxide, hydroxide, carbonate, oxyhalide and hydroxyhalide (wherein the halide is at least one of fluorine and chlorine), and depositing such magnesium compound within the diaphragm.
Claim 8
Dependent Claim
20 words
The process of claim 5 wherein, before said treating, the diaphragm has been subjected to electrolysis in a chlor-alkali cell.
Claim 9
Dependent Claim
29 words
The process of claim 6 wherein the electrolysis has been sufficient to increase the operating voltage of the diaphragm and the treatment decreases the operating voltage for subsequent electrolysis.
Claim 10
Dependent Claim
14 words
The diaphragm of claim 4 wherein the fluoropolymer binder is a fluorocarbon polymer binder.
References Cited (Backward Citations)
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US3849243A
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US4003818A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-11-05 | 1983-05-07 | 1983-11-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-11-05 | 1987-05-07 | 1987-11-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-11-05 | 1991-05-07 | 1991-11-06 | $7700.00 | Window Closed / Lapsed |