EP0124125B1 - Cellule d'électrolyse et méthode de production d'halogène - Google Patents

Cellule d'électrolyse et méthode de production d'halogène Download PDF

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Publication number
EP0124125B1
EP0124125B1 EP84104849A EP84104849A EP0124125B1 EP 0124125 B1 EP0124125 B1 EP 0124125B1 EP 84104849 A EP84104849 A EP 84104849A EP 84104849 A EP84104849 A EP 84104849A EP 0124125 B1 EP0124125 B1 EP 0124125B1
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EP
European Patent Office
Prior art keywords
cathode
membrane
cell
anode
overvoltage
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.)
Expired
Application number
EP84104849A
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German (de)
English (en)
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EP0124125A3 (en
EP0124125A2 (fr
Inventor
Oronzio De Nora
Antonio Nidola
Gian Nicola Martelli
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
De Nora SpA
Original Assignee
Oronzio de Nora Impianti Elettrochimici SpA
De Nora Permelec SpA
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Publication date
Priority claimed from US06/490,515 external-priority patent/US4615775A/en
Application filed by Oronzio de Nora Impianti Elettrochimici SpA, De Nora Permelec SpA filed Critical Oronzio de Nora Impianti Elettrochimici SpA
Priority to AT84104849T priority Critical patent/ATE35700T1/de
Publication of EP0124125A2 publication Critical patent/EP0124125A2/fr
Publication of EP0124125A3 publication Critical patent/EP0124125A3/en
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Publication of EP0124125B1 publication Critical patent/EP0124125B1/fr
Expired legal-status Critical Current

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    • 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
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/34—Simultaneous production of alkali metal hydroxides and chlorine, oxyacids or salts of chlorine, e.g. by chlor-alkali electrolysis
    • C25B1/46—Simultaneous production of alkali metal hydroxides and chlorine, oxyacids or salts of chlorine, e.g. by chlor-alkali electrolysis in diaphragm cells
    • 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
    • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
    • C25B9/60—Constructional parts of cells
    • C25B9/65—Means for supplying current; Electrode connections; Electric inter-cell connections

Definitions

  • the invention relates to an electrolytic cell comprising an ion-exchange membrane or diaphragm dividing the cell into an anode compartment and a cathode compartment, a foraminous substantially rigid anode in the anode compartment and in contact with said membrane or diaphragm, and a foraminous cathode including a metallic screen and a resilient metallic wire element in the cathode compartment.
  • a solid polymer electrolyte cell is characterized by an ion exchange membrane, which separates electrode of the cell and by the fact that one or preferably both electrodes are in contact with the membrane.
  • the solid polymer electrolyte cells present (with respect to conventional membrane cells in which the cathode and frequently both anode and cathode are separated from the membrane), several advantages useful in different electrolysis processes. More precisely:
  • the ion permeable diaphragms are cation exchange polymer in the form of thin flexible sheets or membranes. Generally they are imperforate and do not permit a flow of anolyte into the cathode chamber, but it has also been suggested that such membranes may be provided with some small perforations to permit a small flow of anolyte therethrough, although the bulk of the work appears to have been accomplished with imperforate membranes.
  • Typical polymers which may be used for this purpose include fluorocarbon polymers such as polymers of trifluoroethylene or tetrafluoroethylene or copolymers thereof which contain ion exchange groups are used for this purpose.
  • the ion exchange groups normally are cationic groups including sulfonic acid, sulfonamide, carboxylic acid, phosphoric acid and the like, which are attached to the fluorocarbon polymer chain through carbon and which exchange cations. However, they may also contain anion exchange groups.
  • Such membranes have the general formula:
  • Such membranes include typically those fluorocarbon ion exchange polymers manufactured by the Du Pont Company under the trade name of "Nafion” * and by Asahi Glass Company of Japan under the trade name of "Flemion” 0
  • Patents which describe such membranes include British Patent No. 1,184,321 and U.S. Patent No. 3,282,875 and U.S. No. 4,075,405.
  • EP-A-050 373 describes an electrolysis cell for electrolyzing aqueous halide solutions, which comprises an anolyte chamber and a catholyte chamber separated by a permeable membrane or diaphragmn.
  • At least one electrode comprises at least two sections.
  • One section includes a gas and electrolyte permeable layer, sheet or mat having a catholytic surface with low overvoltage.
  • 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 has an electrode surface having a higher overvoltage than the first electrode surface.
  • the cathode In cells of the type contemplated, the cathode is in close proximity to or in direct contact with the ion exchange membrane. They must be sufficiently permeable to permit rapid escape of evolved gas from the points of their evolution and to provide ready access of liquid electrolyte to these points as well as rapid removal of evolved alkali or other electrolysis produced from such points. Thus the electrodes are normally quite porous.
  • cathodic efficiency is relatively low for example 85% or below and that oxygen in appreciable concentration, for example above 0.5 to 1% or more by volume, is evolved in the chlorine produced.
  • the high alkalinity may induce dehydration of the membrane with consequent decrease of the electrical conductivity, moreover the high concentration gradient increases the back-diffusion of the hydroxyl ions towards the anode with a resulting loss of the faraday efficiency.
  • This invention relates to an electrolytic cell comprising an ion-exchange membrane or diaphragm dividing the cell into an anode compartment and a cathode compartment, a foraminous substantially rigid anode in the anode compartment and in contact with said membrane or diaphragm, and a foraminous cathode including a metallic screen and a resilient metallic wire element in the cathode compartment, which is characterized in that the metallic screen has a surface of a low hydrogen overvoltage, and the resilient metallic wire element has a surface of higher hydrogen overvoltage than the surface of said screen, said element being interposed in a compressed state between said screen and the membrane or diaphragm and having a free volume of at least 75% of the total volume occupied by the element itself.
  • halogen is effectively generated by electrolyzing an aqueous halide in an electrolytic cell of the above type where at least one electrode, preferably the cathode, comprises two elements.
  • the first element metallic screen
  • the second element metallic wire mat
  • the second element has a higher overvoltage (hydrogen overvoltage if used as cathode or chlorine overvoltage if used as anode) and is between the element with lower overvoltage and the membrane, generally being in direct contact with the membrane.
  • both elements are electroconductive and are capable of being polarized as an electrode. Furthermore both elements are in direct electrical contact so that there is little or substantially no potential difference between them.
  • the first or rear most cathode element has a lower hydrogen overvoltage surface than that of the second element engaging the membrane, a major portion and even substantially all of the cathodic electrolysis occurs at points spaced by the second element from the membrane.
  • Said first element where the major electrolysis takes place is readily porous and permits ready flow including lateral flow of catholyte therethrough.
  • it may be in the form of fine mesh flexible electroconductive metal screen having 3 to 10 mesh openings per centimeter or a mat of undulating wire screen or a combination thereof.
  • the openings are relatively large and thus provide channels adjacent to the points of contact between the conductive second element acting as spacer and the first catalytic cathode element whereby catholyte may flow sweeping away evolved alkali from the front portion of the cathode, as well as from the areas remote from the membrane.
  • the more active cathode element may have a surface comprising a platinum group metal or oxide thereof which has a very low hydrogen overvoltage.
  • the intermediate second element acting as a spacer can have an electroconductive surface of a metal or of an oxide which is higher in overvoltage.
  • Silver, stainless steel or nickel may be lused for this purpose.
  • other conductive materials which are resistant to corrosion in the alkaline cathode area may also be used.
  • the intermediate second element in any case is porous and permeable to electrolyte. Being quite electroconductive, it may cooperate in transmitting current to the more remote active cathode areas without serious increase in overall voltage.
  • the intermediate second element acting as a spacer comprises an electroconductive resiliently compressible wire mat which has a surface of higher hydrogen overvoltage than the surface of the main or catalytic cathode layer.
  • the resiliently compressible wire mat forming the intermediate second element acting as a spacer is advantageously compressed, upon assembly of the cell, between the membrane and the active or catalytic first element of the cathode. Therefore the intermediate resilient second element exerts an elastic reaction force against the membrane and the active first element during operation and effectively maintains spaced the surface of the membrane and that of the active cathode.
  • the resiliently compressed wire mat forming the intermediate second element besides acting to maintain a certain separation between the main active element of the electrode and the surface of the membrane, also provides for restraining the flexible membrane from fluttering under the action of the gas bubbles induced turbulence of both the anolyte and the catholyte or from bending towards the anode or the cathode under the action of varying hydraulic heads differentials.
  • This is of great importance since it has been found that membranes which were assembled in cells without resilient or other means capable to maintain them firmly in place are often subjected to chafing by the continuous rubbing of the membrane against the foraminous metal electrodes.
  • the rigid mechanical restraints of the compressed mat are provided on one side by the substantially rigid foraminous anode against which the flexible membrane bears and on the other side by a substantially rigid foraminous pressure plate which may itself be the active catalytic element of the cathode or it may be the current distributor against which the foraminous catalytic element of the cathode bears.
  • the resiliently compressed mat has two functions; one is to provide and secure a certain separation, preferably from 1 to 4 mm, between the surface of the membrane and the surface of the active cathode element during operation of the cell, the other is to press the active cathode element against the rigid current distributing means for a satisfactory operation of the cathode.
  • the active cathode element most advantageously is made of a catholyte resistant metal such as iron, stainless steel, nickel, copper or alloys thereof, coated with a catalytic material having a low hydrogen overvoltage, such as a noble metal (Pt, Rh, Ru, lr, Pd) or alloy thereof or a conductive oxide thereof or of other metals and that these coatings, which impart low hydrogen overvoltage characteristic to the main cathode element, are seldom permanent but need to be renewed after a certain period of operation, it is evident that a great advantage derives from the possibility, offered by this preferred embodiment of the invention, to substitute the worn out active cathode element without having to disconnect or to cut welds and to weld or connect back in place the newly coated cathode.
  • a catholyte resistant metal such as iron, stainless steel, nickel, copper or alloys thereof
  • a catalytic material having a low hydrogen overvoltage such as a noble metal (Pt, Rh, Ru, lr, Pd)
  • the active cathode element may be a thin foraminous coated metal screen which is simply sandwiched between the resiliently compressed second element (e.g. a mat) and a substantially rigid pressure plate or a series of spaced ribs or stubs, acting as the current distribution means to the active cathode element.
  • the resiliently compressed second element e.g. a mat
  • a substantially rigid pressure plate or a series of spaced ribs or stubs acting as the current distribution means to the active cathode element.
  • the resiliently compressible mat forming the element of relatively high hydrogen overvoltage, is pliable and springlike in character and while capable of being compressible to a reduction of up to 60 percent or more of its uncompressed thickness against the membrane by application of pressure from the compression means, it is also capable of springing back substantially to its initial thickness upon release of the clamping pressure.
  • the compressible mat should also provide ready circulation of the electrolyte to and from the membrane surface.
  • the compressible mat is open in structure and includes a large free volume.
  • the resiliently compressible mat is essentially electrically conductive on its surface, generally being made of a metal resistant to the electrochemical attack of the electrolyte in contact therewith and it thus helps distributing polarity and current over the main active electrode element.
  • the resilient element consists of a substantially open mesh, planar, electroconductive metal-wire article or screen having an open network and is comprised of wire or fabric resistant to the electrolyte and the electrolysis products and in that some or all of the wires form a series of coils, waves or crimps or other undulating contour whose diameter or amplitude is substantially in excess of the wire thickness and preferably corresponds to the article thickness, along at least one directrix parallel to the plane of the article. Of course such crimps or wrinkles are disposed in the direction across the thickness of the screen.
  • These wrinkles in the form of crimps, coils, waves or the like have side portions which are sloped or curved with respect to. the axis normal to the thickness of the wrinkled fabric so that, when the layer is compressed, some displacement and pressure is transmitted laterally so as to make distribution of pressure more uniform over the electrode area or surface.
  • Some coils or wire loops which, because of irregularities on the planarity or parallelism of the surface compressing the fabric, may be subjected to a compressive force greater than that acting on adjacent areas, are capable of yielding more to discharge the excess force by transmitting it to the neighboring coils or wire loops.
  • the fabric is effective in acting as a pressure equalizer to a substantial extent and in preventing the elastic reaction force acting on a single contact point to exceed the limit whereby the membrane is excessively pinched or pierced.
  • the resilient element are also instrumental in obtaining a good and uniform contact distribution over the entire surface of the electrode.
  • One very effective embodiment desirably consists of a series of helicoidal cylindrical spirals of wire whose cells are mutually wound with the ones of the adjacent spiral in an intermeshed or interlooped relationship.
  • the diameter of the spirals is 5 to 10 or more times the diameter of the wire of the spirals.
  • the wire helix itself represents a very small portion of the volume enclosed by the helix and therefore the helix is open on all sides thereby providing an interior channel to permit circulation of the electrolyte.
  • the helicoidal cylindrical spirals may also consist of single adjacent metal wire spirals.
  • the spirals are juxtaposed one beside another with the respective coils being merely engaged in an alternate sequence.
  • the second element consists of a crimped knitted mesh or fabric of metal wire wherein every single wire forms a series of waves of an amplitude corresponding to the maximum height of the crimping of the knitted mesh or fabric.
  • two or more knitted meshes or fabrics, after being individually crimped by forming may be superimposed one upon another to obtain a layer of the desired thickness.
  • the crimping of the metal mesh or fabric imparts to the element a great compressibility and an outstanding resiliency to compression under a load which may be at least about 50-2000 grams per square centimeter (g/cm 2 ) of surface applying the pressure.
  • Each of the above described resilient elements is capable of being compressed to a much lower thickness and volume, for example, it may be compressed to about 50 to 90 percent or even lesser percent of its initial volume and/or thickness and is, therefore, pressed or compressed between the membrane and the active cathode element.
  • the resilient element is movable or slideable with respect to the adjacent surfaces of the membrane and of the active cathode element between which it is compressed.
  • the wire loops or coils constituting the resilient element may deflect and slide laterally and distribute pressure uniformly over the entire surfaces with which it contacts.
  • a large portion of the clamping pressure of the cell is elastically memorized by every single coil or wave of the vetal wires forming the second element.
  • a resilient mat when used it is compressed to about 80 to 30 per cent of its original uncompressed thickness under a compression pressure which is comprised between 50 and 2000 grams per square centimeter of projected area. Even in its compressed state, the resilient mat must be highly porous and the ratio between the voids volume and the apparent volume of the compressed mat expressed in percentage is advantageously at least 75% and preferably is comprised between 85% and 96%.
  • the diameter of the wire utilized may vary within a wide range depending on the type of forming or texturing being low enough in any event to obtain the desired characteristics of resiliency and deformation at the cell-assembly pressure.
  • An assembly pressure corresponding to a load between 50 and 500 g/cm 2 of electrodic surface is normally required to obtain a good electrical contact between the active cathode element and the cooperating current distribution structures or collectors although higher pressures may be used.
  • the metal wire diameter is preferably between 0.1 or even less and 0.3 millimeters, while the thickness of the non-compressed article, that is, either the coils' diameter or the amplitude of the crimping is 5 or more times the wire diameter, preferably in the range of 4 to 10 millimeters.
  • the compressible element encloses a large free volume, i.e. the proportion of occupied volume which is free and open to electrolyte flow and gas flow.
  • this percent of free volume is about 75% of the total volume occupied by the fabric. Pressure drop in the flow of gas and electrolyte through such a fabric is negligible.
  • the cell comprises an anode end plate 1 and a cathode end plate 2, both mounted in a vertical plane with each end-plate in the form of a channel having side walls respectively enclosing an anode space 3 and a cathode space 4.
  • Each end plate also has a peripheral seal surface on side-walls projecting on each side of the cell from the plane of the respective end plate, 5 being the anode seal surface and 6, being the cathode seal surface.
  • the anode 8 may comprise a relatively rigid uncompressible sheet of expanded titanium metal or other perforate, anodically resistant substrate, preferably having a nonpassivatable coating thereon such as a metal or oxide or mixed oxide of a platinum group metal.
  • This sheet is sized to fit within the side walls of the anode back plate and is supported rather rigidly by spaced electroconductive ribs 109 which are fastened to and project from the web or base of the anode endplate 1.
  • the spaces between the ribs provide for ready flow of anolyte which is fed into the bottom and withdrawn from the top of such spaces.
  • the entire end plate and ribs may be of graphite and alternatively, it may be of titanium clad steel or other suitable material.
  • the rib ends bearing againstthe anode sheet 8 may or may not be coated, e.g. with platinum or a like metal to improve the electrical contact and the anode sheet 8 may, if desired, be welded to the ribs 109.
  • the anode rigid foraminous sheet 8 is held firmly in an upright position. This sheet may be of expanded metal having upwardly, inclining openings 10 directed away from the membrane (see Fig. 2) to deflect rising gas bubbles towards the space 9 and away from the membrane.
  • ribs 111 extend outward from the base of the cathode end plate 2 a distance which is a fraction of the entire depth of the cathode space 4. These ribs are spaced across the cell to provide parallel space for vertical electrolyte flow from bottom to top and engage the cathode, which is in sheet or layer form.
  • the cathode end plate and ribs may be made of steel or a nickel iron alloy or other cathodically resistant electroconductive material.
  • On the conductive ribs 11 is welded a relatively rigid pressure plate 12, which is perforated and readily allows circulation of electrolyte from one side thereof to the other.
  • the pressure plate is electroconductive and serves to impart cathodic polarity to the electrode and to apply pressure thereto and it may be made of expanded metal or heavy screen of steel, nickel, copper or alloys thereof.
  • the main or active cathode element may advantageously be made of a fine flexible screen 13 of a cathodically resistant electroconductive material, such as nickel, stainless steel, iron, copper or alloys thereof, coated with a cathodically resistant catalytic material having a low hydrogen overvoltage.
  • a cathodically resistant electroconductive material such as nickel, stainless steel, iron, copper or alloys thereof
  • a cathodically resistant catalytic material having a low hydrogen overvoltage is known in the art, particularly suitable materials are the noble metals such as platinum, ruthenium, palladium, rhodium, iridium and osmium, their alloys and oxides, Raney nickel, molybdenum and tungsten alloys. Any of these materials can be used successfully to coat the cathode screen.
  • the resiliently compressible element 14, interposed between membrane 7 and the main active element 13 may be made of a crimped corrugated or wrinkled conpressible wire-mesh fabric which fabric is advantageously an open mesh knitted- wire mesh of the type described in U.S. Patent No. 4,343,690, wherein the wire strands are knitted into a relatively flat fabric with interlocking loops.
  • This fabric is then crimped or wrinkled into a wave or undulating form with the waves being close together, for example 0.3 to 2 cm apart, and the overall thickness of the compressible fabric is 2 to 10 mm.
  • the crimps may be in a zig-zag or herringbone pattern and the mesh of the fabric is coarser, i.e. has a larger pore size than that of screen 13.
  • the resiliently compressible element 14 is instrumental in providing for a good electrical contact between the pressure plate 12 and the main or active cathode element 13, which is pressed by the element 14 against the current distributor pressure plate 12 uniformly over the entire electrode surface.
  • the resiliently compressible element 14 also presses and maintains the flexible membrane 7 bearing against the rigid foraminous anode 8, thus preventing its movement and fluttering in the cell.
  • the element 14 effectively spaces the surface of the main or active cathode element from the membrane of an easily predetermined distance which preferably may be comprised between 1 and 4 mm.
  • the electrode reactions take place substantially at the surface of the catalytic screen 13 and because of the very open structure of the compressed element 14 of fine metal wire.
  • the products of the electrode reaction are easily diluted and quickly removed from the surface of the membrane, thus effectively preventing high concentration gradients across the surface of the membrane.
  • substantially saturated sodium chloride aqueous solution is fed into the bottom of the anolyte compartment of the cell and flows upward through channels or spaces 3 between ribs 109 and depleted brine and evolved chlorine escapes from the top of the cell.
  • Water or dilute sodium hydroxide is fed into the bottom of the cathode chamber and rises through channels 4 as well as through the voids of the compressed element 14 and evolved hydrogen and alkali is withdrawn from the top of the cell.
  • Electrolysis is caused by imparting a direct current electric potential between the anode and cathode end plates.
  • the openings in pressure plate 12 are louvered to provide an inclined outlet directed upwardly away from the compressed fabric element 14, whereby some portion of evolved hydrogen and/or electrolyte escapes to the rear electrolyte chamber 4. Therefore, the vertical spaces at the back of the pressure plate 12 and the space occupied by the compressed fabric 14 are provided for upward catholyte and gas flow.
  • aqueous brine containing from 140 to 300 grams per liter of sodium chloride is circulated within the anode compartment of the cell.
  • Chlorine is evolved at the anode, while the solvated ions tend to migrate through the cation membrane and reach the cathode where caustic soda of substantial concentration above 15-20% by weight and hydrogen is evolved.
  • Solutions containing 25 to 40% by weight of alkali metal hydroxide may be produced with anode and cathode efficiencies above 90%, frequently above 94%.
  • a laboratory size electrolytic cell was manufactured having an effective electrode area 100 millimeters (mm) high and 100 millimeters (mm) wide.
  • the cell frames and back plates were made of titanium for the anodic portion and of stainless steel (AISI 316) for the cathodic portion.
  • the anode was an expanded titanium sheet 1.5 mm thick, coated with a non passivatable catalytic coating of a mixture of oxides of Ruthenium and Titanium in the respective weight ratio of 1 to 1, as referred to the metals, obtained by thermal decomposition of a solution of the salts of the metals.
  • the depth of the anode chamber behind the anode was 12 millimeters (mm).
  • the membrane was a laminated sheet having a thickness of about 0.25 mm, comprising two layers of cation exchange resin laminated together with an interlayer of a polytetrafluoroethylene screen, as mechanical support.
  • the two layers are made of a copolymer of tetrafluoroethylene and a perfluorovinylether, one containing sulphonic groups and the other containing carboxylic groups.
  • the membrane was assembled in the cell with its carboxylic layer facing the catholyte compartment.
  • the cathode structure comprised:
  • the catalytic cathode element b) was interposed between the rigid current collector a) and the resilient element c) and, upon the clamping together of the cell, the current collector was compressing the resilient mat against the surface of the membrane, which membrane was bearing in turn against the rigid anode.
  • the compression corresponding to a pressure of about 400 gram per square centimeter was reducing the thickness of the resilient mat, interposed between the active cathode screen and the membrane, from its original uncompressed thickness of about 6 mm down to about 2.7 millimeters. Therefore, the distance between the surface of the anode and the surface of the active cathode element was about 2.7 millimeters plus the thickness of the membrane, that is practically it was comprised between 2.7 and 2.8 millimeters.
  • the cell operated at the following conditions:
  • Example 2 The same cell as described in Example 1 was disassembled and the main (or catalytic) cathode element of coated nickel b) was placed against the surface of the membrane, the resilient mat of knitted nickel wire c) was placed between the rigid current collector a) and the active cathode element.
  • the resilient mat Upon re-assembly of the cell, the resilient mat was compressed to a thickness of about 2.7 mm, thereby pressing the active cathode element against the surface of the membrane. Therefore, the distance between the surface of the anode and the surface of the cathode corresponded to the thickness of the membrane, that is about 0.25 millimeters.
  • the method of the invention may be practiced with any type of ion permeable membrane.
  • the membrane may be of the monolayer type or it may be a laminated membrane comprising different layers made of different ion exchange resins and the membrane may also include reinforcing fibers or fabrics.
  • the surface of the membrane may be modified either in their chemical composition or in their physical morphology, for example the membrane may have a roughened surface.
  • the membrane may have a porous layer of resin or of particulate material forming a microporous layer over the surface of the membrane, said layer being either conductive or non conductive in character.
  • the current distribution means which in the preferred embodiment described in the accompanying drawings are depicted in the form which comprises a substantially rigid foraminous plate 12, may be of different nature, for example the active cathode element 13 may be pressed by the resilient wire mat directly against the vertical ribs 11, extending from the cathode end plate.
  • the active cathode element 13 can be made of a heavier gauge screen and the distribution of the vertical ribs may be made more dense, that is with a larger number of ribs per unit or width of the cell compartment, in order to provide sufficient number of electric contact points between the active element and the current distribution means.

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  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
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Claims (3)

1. Une cellule électrolytique comprenant une membrane ou diaphragme (7) d'échange d'ions divisant la cellule en un compartiment d'anode et un compartiment de cathode, une anode perforée essentiellement rigide (8) dans le compartiment d'anode et en contact avec ladite membrane ou ledit diaphragme (7) et une cathode perforée (12, 13, 14) comprenant un écran métallique (13) et un élément à fil métallique résilient (14) dans le compartiment de cathode, caractérisée en ce que, l'écran métallique (13) présente une surface de faible surtension d'hydrogène et l'élément de fil métallique résilient (14) présente une surface de surtension d'hydrogène supérieure à la surface dudit écran (13), ledit élément (14) étant interposé dans un état comprimé entre ledit écran (13) et la membrane ou diaphragme (7) et ayant un volume libre d'au moins 75% du volume total occupé par l'élément (14) lui-même.
2. La cellule selon la revendication 1, caractérisée en ce que l'écran métallique (13) est un écran souple fin.
3. Utilisation de la cellule selon l'une des revendications 1 et 2 pour réaliser l'électrolyse de chlorures de métaux alcaline aqueux.
EP84104849A 1983-05-02 1984-04-30 Cellule d'électrolyse et méthode de production d'halogène Expired EP0124125B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT84104849T ATE35700T1 (de) 1983-05-02 1984-04-30 Elektrolysezelle und verfahren zur herstellung von halogenen.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US06/490,515 US4615775A (en) 1979-08-03 1983-05-02 Electrolysis cell and method of generating halogen
US490515 2000-01-25

Publications (3)

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EP0124125A2 EP0124125A2 (fr) 1984-11-07
EP0124125A3 EP0124125A3 (en) 1985-05-15
EP0124125B1 true EP0124125B1 (fr) 1988-07-13

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EP (1) EP0124125B1 (fr)
JP (1) JPH0670276B2 (fr)
AT (1) ATE35700T1 (fr)
DE (1) DE3472686D1 (fr)

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US5599430A (en) * 1992-01-14 1997-02-04 The Dow Chemical Company Mattress for electrochemical cells
ES2533254T3 (es) 2002-11-27 2015-04-08 Asahi Kasei Chemicals Corporation Célula electrolítica bipolar, sin intersticios
ITMI20060054A1 (it) * 2006-01-16 2007-07-17 Uhdenora Spa Distributore di corrente elastico per celle a percolatore
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JPH0670276B2 (ja) 1994-09-07
DE3472686D1 (en) 1988-08-18
JPS59208087A (ja) 1984-11-26
ATE35700T1 (de) 1988-07-15
EP0124125A3 (en) 1985-05-15
EP0124125A2 (fr) 1984-11-07

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