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US4381979A
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Electrolysis cell and method of generating halogen
Assignee: De Nora SpA
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Filing: 1981-05-29
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Granted: 1983-05-03
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Expires: 2001-05-29
Abstract
Abstract Halogen is produced by electrolyzing an aqueous halide in a specially designed cell. The cell comprises an anolyte chamber and a catholyte chamber separated by a permeable membrane or diaphragm, notably an ion exchange (generally cation exchange) polymer. At least one electrode comprises at least two sections. One section comprises a gas and electrolyte permeable layer, sheet or mat having a catalytic surface, i.e. one having a low overvoltage, (low hydrogen overvoltage if the cathode and low halogen overvoltage if the anode). This layer is spaced from the membrane by a second section comprising a thin intermediate electroconductive layer, screen or coating which is in contact with the membrane on one side thereof, the other side thereof being in contact with the main cathode. This second or spacer section advantageously has an electrode surface having a higher overvoltage than the first electrode surface. Preferably the cathode has the above construction. Upon electrolysis of alkali metal chloride or other halide in such a cell and with a cathode of the type described above, a low voltage is obtained even at high current densities and the cathode efficiency is high. The spacer may be in the form of a thin porous coating of metal or the like bonded to or in close contact with the membrane or it may be in the form of a gas and electrolyte permeable screen interposed between the membrane and the lower overvoltage section.
Inventors
- 👤 Oronzio De Nora
- 👤 Antonio Nidola
- 👤 Gian N. Martelli
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:46
CPC Classifications
C; C25; C25B; C25B9/00; C25B9/17; C25B9/19; C25B9/23
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
62 words
A method of generating halogen which comprises electrolyzing an aqueous halide in an electrolytic cell having a pair of opposed electrodes separated by an ion exchange separator at least one of said electrodes having a first electroconductive electrolyte resistant metal screen of relatively low overvoltage and a second electroconductive metal screen of higher overvoltage between the separator and the first metal screen.
Claim 2
Independent Claim
62 words
A method of generating halogen which comprises electrolyzing an aqueous halide in an electrolytic cell having a pair of opposed electrodes separated by an ion exchange separator at least one of said electrodes having a first electroconductive electrolyte resistant metal screen of relatively low overvoltage and a second electroconductive metal screen of higher overvoltage between the separator and the first metal screen.
Claim 3
Dependent Claim
31 words
The method of claim 1 wherein the electrode comprising said metal screens is a cathode and the hydrogen overvoltage of the second screen exceeds the hydrogen overvoltage of the first screen.
Claim 4
Dependent Claim
17 words
The method of claim 1 or 2 wherein said second screen is in contact with the separator.
Claim 5
Independent Claim
27 words
The method according to claims 1 or 2 wherein the area of said first screen exposed to electrolyte is greater than the area of said second screen.
Claim 6
Independent Claim
28 words
The method according to claims 1 or 2 wherein the overvoltage of the second screen is not more than 0.5 volts above the overvoltage of the first screen.
Claim 7
Dependent Claim
31 words
The method of claim 1 wherein the electrode comprising said metal screens is an anode and the chlorine overvoltage of the second screen exceeds the chlorine overvoltage of the first screen.
Claim 8
Independent Claim
17 words
The method according to claims 1 or 2, wherein the separator is a fluorocarbon polycarboxylic acid resin.
Claim 9
Dependent Claim
13 words
The method of claim 1 wherein the high overvoltage section is metallic silver.
Claim 10
Independent Claim
74 words
A method of generating halogen by electrolysis of aqueous halide which comprises conducting the electrolysis between the anode and cathode separated by an ion exchange membrane wherein the cathode comprises a relatively thick electrolyte permeable cathode section spaced from the membrane by an intervening relatively thin electroconductive metal screen in contact with both the membrane and the relatively thick section, said thin electroconductive metal screen having a higher hydrogen overvoltage than said thick section.
Claim 11
Independent Claim
74 words
A method of generating halogen by electrolysis of aqueous halide which comprises conducting the electrolysis between the anode and cathode separated by an ion exchange membrane wherein the cathode comprises a relatively thick electrolyte permeable cathode section spaced from the membrane by an intervening relatively thin electroconductive metal screen in contact with both the membrane and the relatively thick section, said thin electroconductive metal screen having a higher hydrogen overvoltage than said thick section.
Claim 12
Dependent Claim
18 words
The method of claim 9 wherein the thin screen has a thickness not in excess of 5 micron.
Claim 13
Dependent Claim
27 words
The method of claim 9 or 10 wherein the relatively thick section has a surface comprising a platinum group metal or an electroconductive oxide of said metal.
Claim 14
Dependent Claim
47 words
An electrolytic cell comprising a pair of electrodes separated by an ion exchange separator at least one of said electrodes having a first electroconductive electrolyte resistant metal screen of relatively low overvoltage and a second electroconductive surface of higher overvoltage between the separator and the metal screen.
Claim 15
Dependent Claim
47 words
An electrolytic cell comprising a pair of electrodes separated by an ion exchange separator at least one of said electrodes having a first electroconductive electrolyte resistant metal screen of relatively low overvoltage and a second electroconductive surface of higher overvoltage between the separator and the metal screen.
Claim 16
Dependent Claim
20 words
The cell of claim 12 wherein the second metal screen has a higher hydrogen overvoltage than said first metal screen.
Claim 17
Dependent Claim
19 words
The cell of claim 12 wherein the second screen has a higher chlorine overvoltage than said first metal screen.
Claim 18
Dependent Claim
27 words
The cell of claim 12 wherein the surface area of said first surface exposed to electrolyte is greater than the surface area of said second metal screen.
Claim 19
Dependent Claim
18 words
The cell according to claims 13, 14, or 15 wherein the separator is a fluorocarbon polycarboxylic acid resin.
Claim 20
Independent Claim
113 words
A method of generating halogen, alkali, and hydrogen by electrolysis of aqueous alkali metal halide which comprises conducting said electrolysis in a cell having an anode and a cathode separated by an ion exchange membrane at least one of said electrodes being multilayered and comprising a plurality of open wire mesh screens in electrical contact with each other and having an inner screen adjacent the membrane, said inner screen having a surface of higher overvoltage than an outer screen and in electrical contact therewith, said inner screen being thinner than said outer screen, feeding said solution to the anode, and feeding water to the cathode, and evolving hydrogen and alkali at the cathode.
Claim 21
Independent Claim
113 words
A method of generating halogen, alkali, and hydrogen by electrolysis of aqueous alkali metal halide which comprises conducting said electrolysis in a cell having an anode and a cathode separated by an ion exchange membrane at least one of said electrodes being multilayered and comprising a plurality of open wire mesh screens in electrical contact with each other and having an inner screen adjacent the membrane, said inner screen having a surface of higher overvoltage than an outer screen and in electrical contact therewith, said inner screen being thinner than said outer screen, feeding said solution to the anode, and feeding water to the cathode, and evolving hydrogen and alkali at the cathode.
Claim 22
Dependent Claim
25 words
The method of claim 17 wherein the multilayered electrode is a cathode and the inner screen has a higher hydrogen overvoltage than the outer screen.
Claim 23
Dependent Claim
22 words
The method of claim 18 wherein the membrane is coated with a thin porous layer of particles having a high hydrogen overvoltage.
Claim 24
Dependent Claim
17 words
The method of claim 17 or 19 wherein said thicker portion comprises a compressible electroconductive wire mat.
Claim 25
Dependent Claim
29 words
The method of claim 20 wherein the inner screen is nickel or stainless steel and the compressible mat has a coating of a platinum group metal or oxide thereof.
Claim 26
Dependent Claim
16 words
The method of claim 1 wherein the second screen has a surface comprising a metal sulfide.
References Cited (Backward Citations)
US4340452A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-05-02 | 1986-11-01 | 1987-05-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-05-02 | 1990-11-01 | 1991-05-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-05-02 | 1994-11-01 | 1995-05-03 | $7700.00 | Window Closed / Lapsed |