CA1058559A - Sheet-like diaphragms for convoluted shape cathodes - Google Patents
Sheet-like diaphragms for convoluted shape cathodesInfo
- Publication number
- CA1058559A CA1058559A CA233,470A CA233470A CA1058559A CA 1058559 A CA1058559 A CA 1058559A CA 233470 A CA233470 A CA 233470A CA 1058559 A CA1058559 A CA 1058559A
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- Canada
- Prior art keywords
- diaphragm
- support
- cathode
- cell
- anode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
- C25B9/17—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof
- C25B9/19—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof with diaphragms
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
- C25B13/00—Diaphragms; Spacing elements
- C25B13/02—Diaphragms; Spacing elements characterised by shape or form
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
- Hybrid Cells (AREA)
Abstract
SHEET-LIKE DIAPHRAGMS
FOR CONVOLUTED SHAPE CATHODES
Abstract of the Disclosure In a conventional diaphragm electrolytic cell for the production of chlorine and caustic from aqueous alkali metal chloride solutions, the asbestos diaphragm is replaced by a continuous sheet or an endless band of porous polymeric diaphragm material attached to its own support members. Typically, the new diaphragm assembly of this invention is made up of three components, an upper diaphragm support frame, the continuous sheet of porous polymeric diaphragm material and the lower diaphragm support frame.
The diaphragm can be made from polymeric material with a fluorocarbon polymer being illustrative of a suitable material.
FOR CONVOLUTED SHAPE CATHODES
Abstract of the Disclosure In a conventional diaphragm electrolytic cell for the production of chlorine and caustic from aqueous alkali metal chloride solutions, the asbestos diaphragm is replaced by a continuous sheet or an endless band of porous polymeric diaphragm material attached to its own support members. Typically, the new diaphragm assembly of this invention is made up of three components, an upper diaphragm support frame, the continuous sheet of porous polymeric diaphragm material and the lower diaphragm support frame.
The diaphragm can be made from polymeric material with a fluorocarbon polymer being illustrative of a suitable material.
Description
lOS85S9 , BACKGROUND
1. Field of the Invention This invention relates to the use of an endless band or continuous sheet of porous polymeric diaphragm material attached to its own support members as a replace-ment for asbestos diaphragms now found in the conventional diaphragm electrolyti.c cell.
1. Field of the Invention This invention relates to the use of an endless band or continuous sheet of porous polymeric diaphragm material attached to its own support members as a replace-ment for asbestos diaphragms now found in the conventional diaphragm electrolyti.c cell.
2. Description of the Prior Art The production of chlorine from an aqueous alkali metal chloride solution by the use of a diaphragm electro-lytic cell is well known. This type of cell is described in some detail in the well-known textbook Chlorine, Its Manufacture Properties and Uses, J. S. Sconce, Editor, American Chemical Society Monograph No. 154, Reinhold Publishing Corporation, New York, New York (1962~ beginning at page 90. Among the cells described therein is the Hooker cell which has a finger-type of cathode construction.
Thîs cell and other similarly described diaphragm cells employ as the diaphragm an asbestos diaphragm made in situ from a water~-based slurry. The asbestos slurry-type diaphragm has an important advantage in the cells inasmuch as the diaphragm conforms to the convoluted contours of the cathode and presents no attachment problems. The cathode ~ fingers are particularly fabricated from wire screen mesh so that the asbestos diaphragms can be deposited on the cathode from the asbestos slurry. The use of other types of asbestos such as asbestos paper wrapped over the finger-type cathode and sealed at the top and bottom with cement and putty provide a poor seal and loss of current efficiency.
~58S59 There are economic advantages in replacing the asbestos diaphragms by new types of preformed continuous sheet diaphragms, in particular,power and steam savings.
Also with the commercialization of metal anodes which last a long time~ e.g., ~ to 5 years, a durable diaphragm which lasts as long as the anode would e~fect savings in cell maintenance and reconstruction. Furthermore, health problems which may be involved with the handling oE
asbestos would be minimiæed by the replacing of asbestos diaphragms with preformed continuous sheet diaphragms.
The use of other materials as the diaphragm in electrolytic apparatus appears to be limited to situations where the anode/cathode configuration is such that the diaphragm material can be maintained as a ~lat sheet simply by stretching between the opposing anode and cathode. An early patent, U. S. 1,464,689, discloses simply stretching a diaphragm material between a pair of cooperating jaws when the anode is flat. A later U. S. patent, U. S.
Thîs cell and other similarly described diaphragm cells employ as the diaphragm an asbestos diaphragm made in situ from a water~-based slurry. The asbestos slurry-type diaphragm has an important advantage in the cells inasmuch as the diaphragm conforms to the convoluted contours of the cathode and presents no attachment problems. The cathode ~ fingers are particularly fabricated from wire screen mesh so that the asbestos diaphragms can be deposited on the cathode from the asbestos slurry. The use of other types of asbestos such as asbestos paper wrapped over the finger-type cathode and sealed at the top and bottom with cement and putty provide a poor seal and loss of current efficiency.
~58S59 There are economic advantages in replacing the asbestos diaphragms by new types of preformed continuous sheet diaphragms, in particular,power and steam savings.
Also with the commercialization of metal anodes which last a long time~ e.g., ~ to 5 years, a durable diaphragm which lasts as long as the anode would e~fect savings in cell maintenance and reconstruction. Furthermore, health problems which may be involved with the handling oE
asbestos would be minimiæed by the replacing of asbestos diaphragms with preformed continuous sheet diaphragms.
The use of other materials as the diaphragm in electrolytic apparatus appears to be limited to situations where the anode/cathode configuration is such that the diaphragm material can be maintained as a ~lat sheet simply by stretching between the opposing anode and cathode. An early patent, U. S. 1,464,689, discloses simply stretching a diaphragm material between a pair of cooperating jaws when the anode is flat. A later U. S. patent, U. S.
3,~35,074, discloses that in an electrodialysis apparatus having a flat ~ertical anode and a flat vertical cathode at opposite ends of the unit the diaphragm or membrane between the two electrodes can be installed with one free endj if desired.
- SUMMARY OF THE INVENTION
In accordance with the invention there is provided in a diaphragm-type cell for the production of chlorine and caustic from aqueous alkali metal chloride solutions having a plurality of anodes mounted at the bottom of said cell, a cathode between adjacent anodes and spaced between each ~o cathode and anode a diaphragm which divides the celL into anolyte and catholyte compartments the improvement which 5855~
comprises;
a diaphragm assembly composed of an upper diaphragm support, a lower diaphragm support and a continuous diaphragm extending from said upper support to said lower support, both. said diaphragm supports being made of an electrically non-conductive polymeric composition~
said lower support resting on or adjacent to the bottom of said cell and having : openings therein whi:ch allow said anodes to extend through said lower support, said diaphragm being in mechanical connect1on with.said upper - and lower supports so that all of the flow of electrolyte.from th.e anode to :the cathode is through said diaphragm, ~ said diaphragm being maintainable ln : ~ place without the use of keepers, : :
:20 ~ retainers or the like, said cathode : being àt all times separated from saidanode by said dlaphragm and/or upper and lower diaphragm supports.
- DESCRIPTION OF THE DRP~WINGS
, FIG. 1 is a side sectional view of a conventional diaphragm electrolytic cell showing the present invention installed th.erein.
-~ 4 , ~
FIG. 2 is a top cross-sectional view of t~e electrolytic cell taken along ].ine 2-2 of FIG. 1.
FIG. ~ is an expanded schematic drawing showing the elements of the in~ention and their reLationship to the conventional diaphragm elec.trolytic cell.
FIG. 4 is a side cross-sectional view of the conventional diaphragm electrolytic cell wherein an optional modification of the invention has been installed.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
:
The present invention, as shown in FIG. 1, is installed in a typical electrolytic diaphragm cell having cell bottom and bus bar means 10 which is coated a non-conductive sealant layer 12 and through which sealant layer 12 protrudes a~series of spaced anode metal stems 40 for connecting anodes 24-with bus bar means 10. The stem 40 is secured to the bus bar means 10 by use of nut 42. The cell is`completed with the installation of cell sides 16 and cell top 14 along with weak cell liquor outlet 18, hydrogen outlet 20 and chlorine outlet 22, the exact positioning of the foregoing outlets being a matter of choice. The porous cathode 26 is typically made of a ferrous metal with a woven wire construction although other means of fabricating can be employed. The cathode 26 is so formed that it will be one continuous piece but containing a series of openings or passageways through which the anodes 24 can pass and most of the surface of cathode 26 will be parallel to the anodes 24. As a matter of convenience, the cathode 26/diaphragm 36 assembly can be prepared prior to insertion o diaphragm 36 into the cell. This can be conveniently accomplished ~0 by attaching each of the continuous sheet or endless belt ~ 0 5 ~ S S ~
diaphragm 36 to the lower diaphragm support 30, then lowering the cathode 26 down onto the lower diaphragm support 30 so that the diaphragm 36 extends upwardly through the passageways previously provided for the anode 24 and, ~hereafter~ applying the upper diaphragm support 32 to the other edge of the endless band diaphragm 36. This assembly is then set into the cell so that the anode 24 extends through the passageways made by the diaphragm 36 which parallels the passageways of the cathode 26. The cathode 26 and lower diaphragm support 30 are then placed in mechanical and electrical attachment with the cell so that proper position of the cathode 26 and diaphragm 36 will be maintained. Gas seals ~not shown) between sidewall 16 and lower diaphragm support 30 and between sidewall 16 and upper diaphragm support 32 complete the separation between the cathode and anode chambers.
The spaci~l relationships between the anode 2~, diaphragm 36 and cathode 26 are more clearly~shown in the top cross-sectional view of FIG. 2. In this view it will be noted that the anode 2~ is surrounded by diaphragm 36 and the diaphragm 36 i9 in turn surrounded by the cathode 26.
Both the diaphragm 36 and the cathode 26 having a fixed spaced relationship with the anode 24 whereby at any given - point on the surface of anode 24 the cathode ?6 and diaphragm 36 are in substantially the same spaced position as at any other point on anode 24 . In no case is anode 24 in contact with cathode 26 each being at all times distinctly separated from eac~ other by diaphragm 36, l'he diaphragm ~6 thereby forms an anolyte and catholyte chamber for each anode 24 or cathode 26 pair.
The invention is illustrated schematically in FIG. 3 wherein the expanded drawing shows an anode 24 _6_ .
~05!3SS9 embedded in cell bottom 10 and extending through the non-conductive sealant layer 12. The lower diaphragm support 30 contains slots or openings which accommodate the insertion of anode 24. The cathode 26 ~s of woven wire-mesh construction and is so woven that it has openings shaped corresponding to the openings or slots in the lower diaphragm support 30 but of a slightly larger nature thereby accommodating the endless belt diaphragm 36 which is attached to the lower diaphragm support 30 and the upper diaphragm support 32 which has the same configuration as the lower diaphragm support 30.
The lower diaphragm support 30 and the upper diaphragm support 32 are constructed of a chemically inert, electrically non-conducting thermoplastic material such as polyolefin derived from an olefin containing 2 to 4 carbon atoms including polyethylene, polypropylene, polybutene-1 and mixtures thereof~ poIytetrafluoroethylene, copolymers of tetrafluoroethylene and polyperfluoroalkoxy compounds, chlorofluoropolyethylene, polyvinylidene fluoride polymers and acrylonitrile butadiene styrene terpolymers. The properties of these polymers are improved by adding inert, non-conducting yet reinforcing fillers.such as asbestos, glass fibers, mica, kaolin or carbon black. An exemplary composition for use in thls invention is an asbestos filled polypropylene composition, such as disclosed in British Patent 1,246,034. Another equally suitable material is a polytetra-fluoroethylene polymer or copolymer. The upper diaphragm support 32 and the lower diaphragm support 30 are made from the foregoing polymeric materials in such a manner that the support me.mbers 30, 32 are both..
~3S~3559 electr.ically non-conducting and are incapable of permitting the flow of electrolyte from one chamber to the other chamber. It is also within the scope of this invention to make the support frames 30, 32 out of a suitable metal or wire which is completely covered and encased with an insulating polymeric ma~erlal disclosed above.
The endless bel.t diaphragm 36 can be made ou~ of the same polymeric material as the diaphragm support members 30, 32 are made out of or it can be one of the other suitable polymeric materials, e.g., those enumerated above. The endless belt diaphragm 36, however, is so fabricated with`appropriate physical, chemical and electro-chemical properties that it is porous and will permit the flow of electrolyte from one chamber to the other chamber.
The endless belt diaphragm 36 is attached to the diaphragm supports 30, ~2 in any one of several conventional techniques used in fabricating pol~neric objects such as heat-sealing, cementing or friction fit snap-in techniques It is also:within the scope o this invention to use a r~mbination of the attachment techniques mentioned above to attach the dlaphragm 36 to the supports 30, 32. For instance, the diaphragm 36 can be heat-sealed to the lower or bottom support 30 and mechanically, i.e., friction fitted, to the upper diaphragm support 32. The fabricated diaphragm 36 may properly be classified as a porous membrane, or a felted fabric such as are presently employed in the various phases ofelectrolytic cell technology. It is also known in the cell technology to insert between diaphragm 36 and the electrodes, either or both anode 2~ and cathode 263 an iner~ screen (not shown) to facilitate and improve the ~ 0 S ~ 5 5 ~
functionlng of the cell. This modification can be used in conjunction with the present invention~ if desired While the invention has been set forth in terms of the conventional woven wire screen cathodes 26 of the Hooker and Diamond type cells, it is equally applicable to and useful with cathodes 26 made of perforated metal plate formed to a similar spacing arrangement.
The anode 24 can be either a solid metal sheet, a woven wire arrangement or an expanded metal mesh as desired, the exact co~figuration of the anode 24 being beyond the scope of the present invention. Typically, the anode 24 is made of a valve metal and, thereafter, coated.
By a valve metal it is meant metal of tungsten, titanium, zirconium, tantalum and niobium. Preferably, titanium or tantalum is employed and it is normally a commercially pure grade such as electrolytic grade. Alloys of valve metals can be employed as long as the alloy meets the criterion of passivity, metal alloys which become passivated when polarized anodically and can remain passive well beyond anodic potential needed to convert a chloride ion to chlorine The phen~menon of passivity in this connèction is discussed in an article by Greene appearing in the April 1962 issue of Corrosion, pages 136-t to 142-t, wherein reference may be made to FI~. 1 of thP article which describes typical active-passive transition of a metal towards a corrosive medium. Titanium alloys of aluminum, vanadium/ palladium9 chromium or tin can be;employed in which the latter metals are present as less than 10 percent of the alloy.
585S~
It is also well known to coat the anode 24 with at least one platinum group metaI or metal compound, e.g., oxide, to enhance its utility. The platinum group metals include platinum, ruthenium, osmium, rhodium, iridium and palladium and alloys of two or more o the foregoing metals. Many means for applying and the formulations of platinum group metals and compounds for these coatings are known, for instance, see U.S. Patents 3,632,498; 3,630,768; 3,616,446; 3l242,053;
and 3,177,131.
FIG. 4 shows an optional modification of the present in~en~ion which is designed to secure the benefits of the present invention to the diaphragm cell equipped with the conventional Hooker woven wire cathode employed therein. The Hooker woven wire type cathode is well known in the art and generally disclosed in the Sconce textbook discussed above in the background section. In this modification the cell bottom and bus bar 10, the non-conductive sealant layer 12 and anodes 24 with metal stem 40 and retaining nut 42 remain positioned without change as shown in FIG. 1. However, in contrast to the cathode 26/diaphragm 36 arrangement of FIG. 1, the continuous sheet or endless belt d;iaphragm 36, the lower diaphragm support 30 and upper diaphragm support 32 are rearranged so that they form a series of equal distance-spaced closed openings on both sides. This is accomplished by attaching the endless belt diaphragm 36 to the anode 24 openings of the lower diaphragm support 30 as previously disclosed. However, the upper diaphragm support 32 is now realigned so that the prior axial alignment of the openings in the lower diaphragm -r,~,q :.
support 30 and the openings in the upper diaphragm support 32 are completely otlt o:E register. From a top view the openings in the upper support 32 are now spaced equidistant from each two adjacent openings in the lower support 30.
The free end of the endless belt diaphragm 36 for attaching to the upper diaphragm support 32 is now in register with and contacting the solid portion of the upper diaphragm support 32 which is equidistant spaced between two adjacent openings shown in FIG. ~. When the diaphragm 36, upper support 32 and lower support 30 are assembled, the diaphragm 36 is positioned around the anode 24 as before. However, in this case, the Hooker woven wire cathode 26 is inserted from above into the openings of the upper diaphragm support 32. In this case the cathode 26 is separated as before from the anode 24 by the diaphragm 36 and the diaphragm supports 30, 32. But, unlike the case as sho~n in FIGS. l, 2 and 3 the cathode 26 is not encased by the diaphragm 36 and diaphragm supports 30, 32 and can be disengaged from the diaphragm 36 without disassembly of the diaphragm 36 diaphragm supports 32, 30 arrangement. Under this arrangement the conventional diaphragm electrolytic cell can be used as is without modification of the location of the chlorine ou~let 22. Gas seal (not shown) between sidewall 16 and lower diaphragm support 30 completes the separation between the cathode and anode chambers.
Many other modifications and ramifications will naturally suggest themselves to those skilled in the art based on this disclosure. These ramifications and modifications are intended to be comprehended as within the scope of this invention.
- SUMMARY OF THE INVENTION
In accordance with the invention there is provided in a diaphragm-type cell for the production of chlorine and caustic from aqueous alkali metal chloride solutions having a plurality of anodes mounted at the bottom of said cell, a cathode between adjacent anodes and spaced between each ~o cathode and anode a diaphragm which divides the celL into anolyte and catholyte compartments the improvement which 5855~
comprises;
a diaphragm assembly composed of an upper diaphragm support, a lower diaphragm support and a continuous diaphragm extending from said upper support to said lower support, both. said diaphragm supports being made of an electrically non-conductive polymeric composition~
said lower support resting on or adjacent to the bottom of said cell and having : openings therein whi:ch allow said anodes to extend through said lower support, said diaphragm being in mechanical connect1on with.said upper - and lower supports so that all of the flow of electrolyte.from th.e anode to :the cathode is through said diaphragm, ~ said diaphragm being maintainable ln : ~ place without the use of keepers, : :
:20 ~ retainers or the like, said cathode : being àt all times separated from saidanode by said dlaphragm and/or upper and lower diaphragm supports.
- DESCRIPTION OF THE DRP~WINGS
, FIG. 1 is a side sectional view of a conventional diaphragm electrolytic cell showing the present invention installed th.erein.
-~ 4 , ~
FIG. 2 is a top cross-sectional view of t~e electrolytic cell taken along ].ine 2-2 of FIG. 1.
FIG. ~ is an expanded schematic drawing showing the elements of the in~ention and their reLationship to the conventional diaphragm elec.trolytic cell.
FIG. 4 is a side cross-sectional view of the conventional diaphragm electrolytic cell wherein an optional modification of the invention has been installed.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
:
The present invention, as shown in FIG. 1, is installed in a typical electrolytic diaphragm cell having cell bottom and bus bar means 10 which is coated a non-conductive sealant layer 12 and through which sealant layer 12 protrudes a~series of spaced anode metal stems 40 for connecting anodes 24-with bus bar means 10. The stem 40 is secured to the bus bar means 10 by use of nut 42. The cell is`completed with the installation of cell sides 16 and cell top 14 along with weak cell liquor outlet 18, hydrogen outlet 20 and chlorine outlet 22, the exact positioning of the foregoing outlets being a matter of choice. The porous cathode 26 is typically made of a ferrous metal with a woven wire construction although other means of fabricating can be employed. The cathode 26 is so formed that it will be one continuous piece but containing a series of openings or passageways through which the anodes 24 can pass and most of the surface of cathode 26 will be parallel to the anodes 24. As a matter of convenience, the cathode 26/diaphragm 36 assembly can be prepared prior to insertion o diaphragm 36 into the cell. This can be conveniently accomplished ~0 by attaching each of the continuous sheet or endless belt ~ 0 5 ~ S S ~
diaphragm 36 to the lower diaphragm support 30, then lowering the cathode 26 down onto the lower diaphragm support 30 so that the diaphragm 36 extends upwardly through the passageways previously provided for the anode 24 and, ~hereafter~ applying the upper diaphragm support 32 to the other edge of the endless band diaphragm 36. This assembly is then set into the cell so that the anode 24 extends through the passageways made by the diaphragm 36 which parallels the passageways of the cathode 26. The cathode 26 and lower diaphragm support 30 are then placed in mechanical and electrical attachment with the cell so that proper position of the cathode 26 and diaphragm 36 will be maintained. Gas seals ~not shown) between sidewall 16 and lower diaphragm support 30 and between sidewall 16 and upper diaphragm support 32 complete the separation between the cathode and anode chambers.
The spaci~l relationships between the anode 2~, diaphragm 36 and cathode 26 are more clearly~shown in the top cross-sectional view of FIG. 2. In this view it will be noted that the anode 2~ is surrounded by diaphragm 36 and the diaphragm 36 i9 in turn surrounded by the cathode 26.
Both the diaphragm 36 and the cathode 26 having a fixed spaced relationship with the anode 24 whereby at any given - point on the surface of anode 24 the cathode ?6 and diaphragm 36 are in substantially the same spaced position as at any other point on anode 24 . In no case is anode 24 in contact with cathode 26 each being at all times distinctly separated from eac~ other by diaphragm 36, l'he diaphragm ~6 thereby forms an anolyte and catholyte chamber for each anode 24 or cathode 26 pair.
The invention is illustrated schematically in FIG. 3 wherein the expanded drawing shows an anode 24 _6_ .
~05!3SS9 embedded in cell bottom 10 and extending through the non-conductive sealant layer 12. The lower diaphragm support 30 contains slots or openings which accommodate the insertion of anode 24. The cathode 26 ~s of woven wire-mesh construction and is so woven that it has openings shaped corresponding to the openings or slots in the lower diaphragm support 30 but of a slightly larger nature thereby accommodating the endless belt diaphragm 36 which is attached to the lower diaphragm support 30 and the upper diaphragm support 32 which has the same configuration as the lower diaphragm support 30.
The lower diaphragm support 30 and the upper diaphragm support 32 are constructed of a chemically inert, electrically non-conducting thermoplastic material such as polyolefin derived from an olefin containing 2 to 4 carbon atoms including polyethylene, polypropylene, polybutene-1 and mixtures thereof~ poIytetrafluoroethylene, copolymers of tetrafluoroethylene and polyperfluoroalkoxy compounds, chlorofluoropolyethylene, polyvinylidene fluoride polymers and acrylonitrile butadiene styrene terpolymers. The properties of these polymers are improved by adding inert, non-conducting yet reinforcing fillers.such as asbestos, glass fibers, mica, kaolin or carbon black. An exemplary composition for use in thls invention is an asbestos filled polypropylene composition, such as disclosed in British Patent 1,246,034. Another equally suitable material is a polytetra-fluoroethylene polymer or copolymer. The upper diaphragm support 32 and the lower diaphragm support 30 are made from the foregoing polymeric materials in such a manner that the support me.mbers 30, 32 are both..
~3S~3559 electr.ically non-conducting and are incapable of permitting the flow of electrolyte from one chamber to the other chamber. It is also within the scope of this invention to make the support frames 30, 32 out of a suitable metal or wire which is completely covered and encased with an insulating polymeric ma~erlal disclosed above.
The endless bel.t diaphragm 36 can be made ou~ of the same polymeric material as the diaphragm support members 30, 32 are made out of or it can be one of the other suitable polymeric materials, e.g., those enumerated above. The endless belt diaphragm 36, however, is so fabricated with`appropriate physical, chemical and electro-chemical properties that it is porous and will permit the flow of electrolyte from one chamber to the other chamber.
The endless belt diaphragm 36 is attached to the diaphragm supports 30, ~2 in any one of several conventional techniques used in fabricating pol~neric objects such as heat-sealing, cementing or friction fit snap-in techniques It is also:within the scope o this invention to use a r~mbination of the attachment techniques mentioned above to attach the dlaphragm 36 to the supports 30, 32. For instance, the diaphragm 36 can be heat-sealed to the lower or bottom support 30 and mechanically, i.e., friction fitted, to the upper diaphragm support 32. The fabricated diaphragm 36 may properly be classified as a porous membrane, or a felted fabric such as are presently employed in the various phases ofelectrolytic cell technology. It is also known in the cell technology to insert between diaphragm 36 and the electrodes, either or both anode 2~ and cathode 263 an iner~ screen (not shown) to facilitate and improve the ~ 0 S ~ 5 5 ~
functionlng of the cell. This modification can be used in conjunction with the present invention~ if desired While the invention has been set forth in terms of the conventional woven wire screen cathodes 26 of the Hooker and Diamond type cells, it is equally applicable to and useful with cathodes 26 made of perforated metal plate formed to a similar spacing arrangement.
The anode 24 can be either a solid metal sheet, a woven wire arrangement or an expanded metal mesh as desired, the exact co~figuration of the anode 24 being beyond the scope of the present invention. Typically, the anode 24 is made of a valve metal and, thereafter, coated.
By a valve metal it is meant metal of tungsten, titanium, zirconium, tantalum and niobium. Preferably, titanium or tantalum is employed and it is normally a commercially pure grade such as electrolytic grade. Alloys of valve metals can be employed as long as the alloy meets the criterion of passivity, metal alloys which become passivated when polarized anodically and can remain passive well beyond anodic potential needed to convert a chloride ion to chlorine The phen~menon of passivity in this connèction is discussed in an article by Greene appearing in the April 1962 issue of Corrosion, pages 136-t to 142-t, wherein reference may be made to FI~. 1 of thP article which describes typical active-passive transition of a metal towards a corrosive medium. Titanium alloys of aluminum, vanadium/ palladium9 chromium or tin can be;employed in which the latter metals are present as less than 10 percent of the alloy.
585S~
It is also well known to coat the anode 24 with at least one platinum group metaI or metal compound, e.g., oxide, to enhance its utility. The platinum group metals include platinum, ruthenium, osmium, rhodium, iridium and palladium and alloys of two or more o the foregoing metals. Many means for applying and the formulations of platinum group metals and compounds for these coatings are known, for instance, see U.S. Patents 3,632,498; 3,630,768; 3,616,446; 3l242,053;
and 3,177,131.
FIG. 4 shows an optional modification of the present in~en~ion which is designed to secure the benefits of the present invention to the diaphragm cell equipped with the conventional Hooker woven wire cathode employed therein. The Hooker woven wire type cathode is well known in the art and generally disclosed in the Sconce textbook discussed above in the background section. In this modification the cell bottom and bus bar 10, the non-conductive sealant layer 12 and anodes 24 with metal stem 40 and retaining nut 42 remain positioned without change as shown in FIG. 1. However, in contrast to the cathode 26/diaphragm 36 arrangement of FIG. 1, the continuous sheet or endless belt d;iaphragm 36, the lower diaphragm support 30 and upper diaphragm support 32 are rearranged so that they form a series of equal distance-spaced closed openings on both sides. This is accomplished by attaching the endless belt diaphragm 36 to the anode 24 openings of the lower diaphragm support 30 as previously disclosed. However, the upper diaphragm support 32 is now realigned so that the prior axial alignment of the openings in the lower diaphragm -r,~,q :.
support 30 and the openings in the upper diaphragm support 32 are completely otlt o:E register. From a top view the openings in the upper support 32 are now spaced equidistant from each two adjacent openings in the lower support 30.
The free end of the endless belt diaphragm 36 for attaching to the upper diaphragm support 32 is now in register with and contacting the solid portion of the upper diaphragm support 32 which is equidistant spaced between two adjacent openings shown in FIG. ~. When the diaphragm 36, upper support 32 and lower support 30 are assembled, the diaphragm 36 is positioned around the anode 24 as before. However, in this case, the Hooker woven wire cathode 26 is inserted from above into the openings of the upper diaphragm support 32. In this case the cathode 26 is separated as before from the anode 24 by the diaphragm 36 and the diaphragm supports 30, 32. But, unlike the case as sho~n in FIGS. l, 2 and 3 the cathode 26 is not encased by the diaphragm 36 and diaphragm supports 30, 32 and can be disengaged from the diaphragm 36 without disassembly of the diaphragm 36 diaphragm supports 32, 30 arrangement. Under this arrangement the conventional diaphragm electrolytic cell can be used as is without modification of the location of the chlorine ou~let 22. Gas seal (not shown) between sidewall 16 and lower diaphragm support 30 completes the separation between the cathode and anode chambers.
Many other modifications and ramifications will naturally suggest themselves to those skilled in the art based on this disclosure. These ramifications and modifications are intended to be comprehended as within the scope of this invention.
Claims (8)
1. In a diaphragm-type cell for the production of chlorine and caustic from aqueous alkali metal chloride solutions having a plurality of anodes mounted at the bottom of said cell, cathodes between adjacent anodes and spaced between each cathode and anode a diaphragm which divides the cell into anolyte and catholyte compartments the improvement which comprises:
a diaphragm assembly composed of an upper diaphragm support, a lower diaphragm support and a continuous diaphragm extending from said upper support to said lower support, both said diaphragm supports being made of an electrically non-conductive polymeric composition, said lower support resting on or adjacent to the bottom of said cell and having openings therein which allow said anodes to extend through said lower support, said diaphragm being in mechanical connection with said upper and lower supports so that all of the flow of electrolyte from the anode to the cathode is through said diaphragm, said diaphragm being maintained in place, said cathode being at all times separated from said anode by said diaphragm and/or upper and lower diaphragm supports.
a diaphragm assembly composed of an upper diaphragm support, a lower diaphragm support and a continuous diaphragm extending from said upper support to said lower support, both said diaphragm supports being made of an electrically non-conductive polymeric composition, said lower support resting on or adjacent to the bottom of said cell and having openings therein which allow said anodes to extend through said lower support, said diaphragm being in mechanical connection with said upper and lower supports so that all of the flow of electrolyte from the anode to the cathode is through said diaphragm, said diaphragm being maintained in place, said cathode being at all times separated from said anode by said diaphragm and/or upper and lower diaphragm supports.
2. The electrolytic cell of claim 1 wherein the openings of the upper diaphragm support and the lower diaphragm support are in axial alignment with each other and the cathode is encased within the upper diaphragm support, the diaphragm and the lower diaphragm support.
3. The electrolytic cell of claim 1 wherein the upper diaphragm support and the lower diaphragm support openings are non-axially aligned so that the system of diaphragm supports and diaphragm form a complete barrier between said anodes and said cathodes without encasing said cathodes.
4. The electrolytic cell of claim 1 wherein the diaphragm support and the diaphragm are made from poly-tetrafluoroethylene polymers or copolymers.
5. The electrolytic cell of claim 1 wherein the diaphragm is a porous sheet material.
6. The electrolytic cell of claim 1 wherein the diaphragm is heat-sealed to the upper and lower diaphragm support members.
7. The electrolytic cell of claim 1 wherein the diaphragm is heat-sealed to the lower diaphragm support member and is mechanically sealed to the upper diaphragm support member.
8. The electrolytic cell of claim 1 wherein separating screens are interposed between the diaphragm and the anode and the cathode.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US497864A US3923630A (en) | 1974-08-16 | 1974-08-16 | Electrolytic cell including diaphragm and diaphragm-support structure |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1058559A true CA1058559A (en) | 1979-07-17 |
Family
ID=23978618
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA233,470A Expired CA1058559A (en) | 1974-08-16 | 1975-08-14 | Sheet-like diaphragms for convoluted shape cathodes |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US3923630A (en) |
| JP (1) | JPS5145697A (en) |
| CA (1) | CA1058559A (en) |
| FR (1) | FR2281999A1 (en) |
| GB (1) | GB1516196A (en) |
| IT (1) | IT1041242B (en) |
| NL (1) | NL7509777A (en) |
Families Citing this family (36)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SU562122A1 (en) * | 1975-07-15 | 1983-11-15 | Предприятие П/Я В-2287 | Diaphragm electrolytic cell for preparing chlorine and alkali |
| US4036728A (en) * | 1976-05-21 | 1977-07-19 | Diamond Shamrock Corporation | Converting a diaphragm electrolytic cell to a membrane electrolytic cell |
| US4167469A (en) * | 1976-10-29 | 1979-09-11 | Olin Corporation | Diaphragms for use in the electrolysis of alkali metal chlorides |
| US4081350A (en) * | 1976-10-29 | 1978-03-28 | Olin Corporation | Diaphragms for use in the electrolysis of alkali metal chlorides |
| US4166785A (en) * | 1976-10-29 | 1979-09-04 | Olin Corporation | Diaphragms for use in the electrolysis of alkali metal chlorides |
| US4115237A (en) * | 1977-01-03 | 1978-09-19 | Olin Corporation | Electrolytic cell having membrane enclosed anodes |
| GB1582593A (en) * | 1977-04-13 | 1981-01-14 | Ici Ltd | Diaphragm cells |
| GB1582705A (en) * | 1977-04-13 | 1981-01-14 | Ici Ltd | Diaphragm cells |
| US4278524A (en) * | 1977-09-26 | 1981-07-14 | Olin Corporation | Diaphragms for use in the electrolysis of alkali metal chlorides |
| US4165271A (en) * | 1977-10-03 | 1979-08-21 | Olin Corporation | Diaphragms for use in the electrolysis of alkali metal chlorides |
| US4207164A (en) * | 1977-10-03 | 1980-06-10 | Olin Corporation | Diaphragms for use in the electrolysis of alkali metal chlorides |
| JPS5526015U (en) * | 1978-08-03 | 1980-02-20 | ||
| JPS5812836Y2 (en) * | 1977-12-26 | 1983-03-11 | 鐘淵化学工業株式会社 | Membrane installation equipment for alkaline chloride electrolyzer |
| GB2013242B (en) * | 1977-12-26 | 1982-06-16 | Kanegafuchi Chemical Ind | Method and apparatus of installation of membrane to electrolytic cell |
| DE2862074D1 (en) * | 1977-12-29 | 1982-12-02 | Ici Plc | A method of joining together of a sheet or sheets of a non melt-processable organic polymer |
| DE2963104D1 (en) * | 1978-07-28 | 1982-08-05 | Ici Plc | Clamping diaphragms or membranes in electrolytic cells |
| JPS5524963A (en) * | 1978-08-10 | 1980-02-22 | Kanegafuchi Chem Ind Co Ltd | Diaphragm fixing device |
| ATE5333T1 (en) * | 1979-07-20 | 1983-12-15 | Imperial Chemical Industries Plc | DIAPHRAGM FOR ENCLOSING A CATHODE CHAMBER OF AN ELECTROLYTIC CELL, FILM FOR MAKING A DIAPHRAGM AND METHOD FOR ENCLOSING A CATHODE CHAMBER. |
| US4229277A (en) * | 1979-08-30 | 1980-10-21 | Olin Corporation | Glove-like diaphragm structure for electrolytic cells |
| US4288310A (en) * | 1979-09-12 | 1981-09-08 | Knight Allan R | Membrane support assembly for electrolytic cell and method of making same |
| US4283264A (en) * | 1979-09-14 | 1981-08-11 | Hooker Chemicals & Plastics Corp. | Electrolytic cell separator, tubular member component thereof and methods for manufacturing and using such separator and component |
| US4289601A (en) * | 1979-11-30 | 1981-09-15 | Olin Corporation | Diaphragm structure for electrolytic cells for the electrolysis of aqueous salt solutions |
| US4361475A (en) * | 1980-01-10 | 1982-11-30 | Innova, Inc. | Membrane block construction and electrochemical cell |
| JPS6051556B2 (en) * | 1980-07-17 | 1985-11-14 | 鐘淵化学工業株式会社 | Diaphragm type electrolytic cell |
| DE3268068D1 (en) * | 1981-03-10 | 1986-02-06 | Ici Plc | Cladding cathodes of electrolytic cell with diaphragm or membrane |
| DE3172133D1 (en) * | 1981-06-23 | 1985-10-10 | Dow Chemical Co | Membrane support assembly for electrolytic cell and method of making same |
| DE3276010D1 (en) * | 1981-07-14 | 1987-05-14 | Asahi Glass Co Ltd | Electrolytic cell |
| US4500379A (en) * | 1982-07-26 | 1985-02-19 | Olin Corporation | Method of making a composite fiber reinforced plastic frame |
| US4402813A (en) * | 1982-07-26 | 1983-09-06 | Olin Corporation | Composite fiber reinforced plastic electrode frame |
| US4439298A (en) * | 1982-07-26 | 1984-03-27 | Olin Corporation | Composite fiber reinforced plastic frame |
| IT1177236B (en) * | 1983-11-17 | 1987-08-26 | Toyo Soda Mfg Co Ltd | PROCEDURE FOR PRODUCING CAUSTIC ALKALINE AGENTS |
| SE466196B (en) * | 1989-06-13 | 1992-01-13 | Pavel Voracek | PROCEDURE AND DEVICE FOR ELECTRICAL TREATMENT OF AN ELECTROLYTIC SOLUTION AND SOLUTION FRACTIONS PREPARED ACCORDING TO THE PROCEDURE |
| DE102007041828A1 (en) * | 2007-09-03 | 2009-03-05 | Siemens Ag | Apparatus and method for reducing pollutants in a liquid and use of such a device |
| DE102009036080A1 (en) | 2009-08-04 | 2011-02-17 | Siemens Aktiengesellschaft | Process for the decomposition of organic pollutants in industrial waste water and associated plant |
| US11203814B2 (en) * | 2016-03-30 | 2021-12-21 | Alcoa Usa Corp. | Apparatuses and systems for vertical electrolysis cells |
| CN113373495B (en) * | 2021-05-27 | 2022-10-04 | 刘鹏 | Induction type nanometer diaphragm |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3312614A (en) * | 1967-04-04 | Diaphragm electrolysis cell | ||
| US1963959A (en) * | 1933-01-23 | 1934-06-26 | Howard E Dorsey | Electrolytic gas producing device |
| US3344053A (en) * | 1964-05-04 | 1967-09-26 | Dow Chemical Co | Chlorine cell |
| US3398080A (en) * | 1965-03-22 | 1968-08-20 | Dow Chemical Co | Mercury vertical cathode electrolytic cell |
| US3408281A (en) * | 1965-07-15 | 1968-10-29 | Dow Chemical Co | Vertical mercury cathode electrolytic cell with diaphragm enclosed perforated cathode support |
-
1974
- 1974-08-16 US US497864A patent/US3923630A/en not_active Expired - Lifetime
-
1975
- 1975-08-13 IT IT50952/75A patent/IT1041242B/en active
- 1975-08-14 FR FR7525352A patent/FR2281999A1/en not_active Withdrawn
- 1975-08-14 CA CA233,470A patent/CA1058559A/en not_active Expired
- 1975-08-15 GB GB34015/75A patent/GB1516196A/en not_active Expired
- 1975-08-15 JP JP50098652A patent/JPS5145697A/ja active Pending
- 1975-08-15 NL NL7509777A patent/NL7509777A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| GB1516196A (en) | 1978-06-28 |
| FR2281999A1 (en) | 1976-03-12 |
| IT1041242B (en) | 1980-01-10 |
| NL7509777A (en) | 1976-02-18 |
| JPS5145697A (en) | 1976-04-19 |
| US3923630A (en) | 1975-12-02 |
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