US3979276A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Silicate treated asbestos diaphragms for electrolytic cells
Assignee: PPG Industries Inc
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Filing: 1975-08-05
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Granted: 1976-09-07
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Expires: 1995-08-05
Abstract
Abstract A diaphragm is disclosed for electrolytic cells, for example, chlor-alkali cells. The diaphragm is characterized in that it has been treated with a water-soluble silicate on the anolyte side. Also disclosed is an electrolytic cell process using such a diaphragm, and a method for preparing such a diaphragm.
Inventors
- 👤 Franklin Strain
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 17:26
CPC Classifications
D; D21; D21J; D21J7/00; C; C25; C25B; C25B13/00; C25B13/04; C25B13/05; C25B13/06; C25B15/00
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
93 words
In a porous sodium chloride brine permeable fibrous chrysotile asbestos diaphragm, the improvement wherein said diaphragm has an amorphous, hydrated silica surface formed by depositing thereon to a depth of at least 0.08 inch from 0.01 to 5.0 grams per square foot of diaphragm area of a water soluble silicate having the empirical formula: (Me.sub.2 O).sub.m (SiO.sub.2).sub.n where Me is chosen from the group consisting of lithium, sodium, and potassium, and the ratio of m to n is from about 1:1 to about 1:10, and thereafter contacting said diaphragm with aqueous acidic media.
Claim 2
Dependent Claim
93 words
In a porous sodium chloride brine permeable fibrous chrysotile asbestos diaphragm, the improvement wherein said diaphragm has an amorphous, hydrated silica surface formed by depositing thereon to a depth of at least 0.08 inch from 0.01 to 5.0 grams per square foot of diaphragm area of a water soluble silicate having the empirical formula: (Me.sub.2 O).sub.m (SiO.sub.2).sub.n where Me is chosen from the group consisting of lithium, sodium, and potassium, and the ratio of m to n is from about 1:1 to about 1:10, and thereafter contacting said diaphragm with aqueous acidic media.
Claim 3
Dependent Claim
18 words
The diaphragm of claim 1 wherein the silicate is chosen from the group consisting of metasilicates and polysilicates.
Claim 4
Dependent Claim
11 words
The diaphragm of claim 2 wherein the silicate is sodium polysilicate.
Claim 5
Dependent Claim
24 words
The diaphragm of claim 1 wherein there is in excess of 0.1 gram per square foot of silicate on the surface of the diaphragm.
Claim 6
Dependent Claim
117 words
In an electrolytic cell cathode structure comprising an electrolyte permeable, catholyte resistant metal member having in contact therewith one surface of a porous sodium chloride brine permeable fibrous chyrsotile asbestos diaphragm, the improvement wherein the opposite surface of the diaphragm has an amorphous, hydrated silica coating formed by depositing thereon to a depth of at least 0.08 inch from 0.01 to 5.0 grams per square foot of diaphragm area of a water soluble silicate having the empirical formula: (Me.sub.2 O).sub.m (SiO.sub.2).sub.n where Me is chosen from the group consisting of lithium, sodium, and potassium, and the ratio of m to n is from about 1:1 to about 1:10, and thereafter contacting said diaphragm with aqueous acidic media.
Claim 7
Dependent Claim
117 words
In an electrolytic cell cathode structure comprising an electrolyte permeable, catholyte resistant metal member having in contact therewith one surface of a porous sodium chloride brine permeable fibrous chyrsotile asbestos diaphragm, the improvement wherein the opposite surface of the diaphragm has an amorphous, hydrated silica coating formed by depositing thereon to a depth of at least 0.08 inch from 0.01 to 5.0 grams per square foot of diaphragm area of a water soluble silicate having the empirical formula: (Me.sub.2 O).sub.m (SiO.sub.2).sub.n where Me is chosen from the group consisting of lithium, sodium, and potassium, and the ratio of m to n is from about 1:1 to about 1:10, and thereafter contacting said diaphragm with aqueous acidic media.
Claim 8
Dependent Claim
19 words
The cathode structure of claim 5 wherein the silicate is chosen from the group consisting of metasilicates and polysilicates.
Claim 9
Dependent Claim
12 words
The cathode structure of claim 6 wherein the silicate is sodium polysilicate.
Claim 10
Dependent Claim
19 words
The cathode structure of claim 5 wherein the diaphragm comprises more than 0.1 gram per square foot of silicate.
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) | 1979-09-07 | 1980-03-08 | 1980-09-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-09-07 | 1984-03-08 | 1984-09-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-09-07 | 1988-03-08 | 1988-09-07 | $7700.00 | Window Closed / Lapsed |