US3318792A - Mercury cathode cell with noble metaltitanium anode as cover means - Google Patents

Mercury cathode cell with noble metaltitanium anode as cover means Download PDF

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Publication number
US3318792A
US3318792A US548032A US54803266A US3318792A US 3318792 A US3318792 A US 3318792A US 548032 A US548032 A US 548032A US 54803266 A US54803266 A US 54803266A US 3318792 A US3318792 A US 3318792A
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United States
Prior art keywords
anode
cell
titanium
cathode
mercury
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Expired - Lifetime
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US548032A
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English (en)
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Cotton Joseph Bernard
Bowen Kevin William Joseph
Ravenscroft Arthur Wesley
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Imperial Chemical Industries Ltd
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Imperial Chemical Industries Ltd
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    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25BELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/04Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • C25B11/051Electrodes formed of electrocatalysts on a substrate or carrier
    • C25B11/073Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25BELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/02Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form
    • C25B11/033Liquid electrodes
    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25BELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/04Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • C25B11/051Electrodes formed of electrocatalysts on a substrate or carrier
    • C25B11/073Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
    • C25B11/075Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound
    • C25B11/081Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound the element being a noble metal
    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25BELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B9/00Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25BELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B9/00Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
    • C25B9/30Cells comprising movable electrodes, e.g. rotary electrodes; Assemblies of constructional parts thereof
    • C25B9/303Cells comprising movable electrodes, e.g. rotary electrodes; Assemblies of constructional parts thereof comprising horizontal-type liquid electrode
    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25BELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B9/00Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
    • C25B9/60Constructional parts of cells
    • C25B9/65Means for supplying current; Electrode connections; Electric inter-cell connections
    • CCHEMISTRY; METALLURGY
    • C25ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25BELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B9/00Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
    • C25B9/70Assemblies comprising two or more cells

Definitions

  • This invention relates to improved anodes for use in electrolytic cells for the manufacture of chlorine and caustic alkali by the electrolysis of aqueous solutions of alkali metal chlorides (hereinafter termed brine), to electrolytic cells incorporating such anodes and to the process of electrolysing brine in such cells.
  • brine alkali metal chlorides
  • cells for the electrolysis of brine fall into two categories, namely those which employ a owing mercury cathode and those which use a fixed cathode separated from the anode by a porous diaphragm- 11n the cells of the lirst category, the alkali metal which is the primary product discharged at the cathode forms an amalgam with the mercury which is carried away into a separate vessel, usually termed denuder, or sometimes a soda cell, where it reacts with water to .form caustic 'alkali and hydrogen and regenerates the mercury for reuse in the prima-ry cell.
  • the alkali metal - is discharged at a xed cathode, usually of mild steel, and reacts at the cathode face with water from the electrolyte to form caustic alkali and liberate hydrogen.
  • chlorine is discharged at the anode which is usually made of graphite.
  • a porous diaphragm is interposed between anode and cathode to prevent as far as possible mixing of the hydrogen and chlorine and mixing of the caustic alkali with the brine.
  • Another vexing problem in constructing and operating cells to electrolyse brine to make chlorine and caustic alkali is that of providing satisfactory internal electrical conductors or connections to the anodes.
  • Such conductors should have low electrical resistance, should be chemically inert to hot brine containing chlorine and to moist chlorine gas, mechanically robust and resistant to linternal strains set up by temperature differentials and they must also be capable of being effectively sealed into the walls or cover of the cell to form a joint impermeable to the gaseous products and to electrolyte which is apt to creep up the Isurface of the graphite anode and its supporting conductors. No fully satisfactory constructional material is yet available for this purpose.
  • anode made of a noble metal of the platinum group namely ruthenium, rhodium, palladium, osmium, iridium or platinum (hereinafter called generically a platinum metal) or an alloy of two or more such metals and an electrically conducting lead to such anode made of titanium or an alloy consisting essentially of titanium.
  • platinum metal platinum
  • platinum would form a chemically and mechanically stable anode for a chlorine cell but platinum (or other metal of this group) in massive form has been ruled out on the ground of expense.
  • the combination of an anode surface of a platinum metal with a titanium supporting and conducting lead shows the following advantages. Both the anode and the conductor are mechanically much more robust and can be fabricated much more readily and accurately to closely prescribed dimensions. Both are chemically more resistance to the corrosive action of the hot chlorine-containing brine.
  • the platinum metal is, of course, intrinsically more resistant and the titanium becomes protected by the formation of an adherent chemically resistant surface layer. This layer also acts as an electrical insulator so that although the titanium is electrically conducting its surface is insulated and it does not itself function as an anode.
  • this insulating layer is self-healing--that is, if it should be mechanically damaged during the installation of the anode or during the operation of the cell, the resulting local electrolytic action regenerates the protective layer and the damage is made good.
  • the titanium conductor does not disintegrate and does not generate carbon dioxide to contaminate the chlorine, nor does it form or liberate impurities in the brine that are liable to catalyse the formation of hydrogen at the cathode of a mercury cell.
  • the titanium is very much less liable than graphite to distort or fracture under internal strains set up by temperature differentials. It is also impervious to the electrolyte which therefore cannot seep through the material of the anode conductor to the outside of the cell.
  • the cell can be more easily sealed.
  • a sheet of titanium can be made to function simultaneously as cell cover and anode support, thus eliminating any need for anode conductors to pass through orifices in the walls or cover of the cell.
  • the anode and its support can be fashioned with much greater precision than a graphite anode and once it has been placed in proper relationship to the cathode, no problems of periodic adjustment arise because the new anode wears away very much more slowly and such wear as does occur does not sensibly increase the interelectrode gap. The requisite close setting, once achieved, is thereafter maintained indenitely.
  • the operative anode surface is of a platinum metal
  • an all-important feature of the design of such a cell is the provision of means whereby the thinnest possible layer of the platinum metal can be accurately supported at the appropriate very short distance from the cathode and fed with an adequate supply of electrical energy.
  • a support and electrical lead constructed of a cheaper and/ or more electrically conductive metal, for instance copper, aluminium or even steel, clad first with titanium and then having the operative anode face which will be opposed to ⁇ the cathode covered with a layer of the platinum metal.
  • Such a structure can, if desired, be made with a series of ports or channels communicating with orifices scattered over the face of the anode so as to allow the chlorine which is there liberated to escape more rapidly from ⁇ the anode surface and pass away through the off-take pipe which is located in the upper part of the cell.
  • an exceedingly simple form of cell with a substantially horizontal cathode for instance a flowing mercury cathode, utilising high speed brine flow and consisting of a trough-shaped base plate Ito bear the mercury cathode, insulating sides and a single block or plate of titanium or titanium-clad steel serving at once as the cell cover, electrically conducting lead and anode support, the lower face thereof being covered or coated with a platinum metal to provide the operative anode and the plate or block being pierced at appropriate intervals to provide off-take ports through which the chlorine is removed from the cell.
  • the facing or coating of a platinum metal which provides the real anode surface may be consistuted, if desired, by a thin sheet or foil which is welded to the titanium support.
  • a layer of the platinum metal electrolytically deposited -on the titanium surface since in this way a given Weight of the platinum metal can be spread over a greater surface of titanium.
  • the over-voltage of chlorine on an electrolytically prepared platinum surface appears to be less than on a surface of massive platinum lsuch ⁇ as a sheet or foil; indeed it is comparable with the over-voltage on graphite.
  • Such cells also customarily incorporate graphite anodes and hence suffer most of the disadvantages and occasion most of the difficulties discussed above; consequently their economy, smoothness of operation and ease of fabrication and maintenance are likewise very considerably improved by the incorporation therein of the new combination of an anode surface of a platinum metal and a supporting and conducting lead of titanium or an alloy consisting essentially of titanium.
  • FIG- URES 1, 2, 3 and 4 of the accompanying drawings wherein FIGURE l represents, in isometric projection, a view of a transverse section of the cell, FIGURE 2 repesents a longitudinal section along the line A-Al, and FIG- URES 3 and 4 are sectional details of the edges of the cell showing how the various constructional members are assembled together.
  • the side members 1 and base plate 2 together with appropriate end members (not shown) define a long rectangular box-like cell borne on channel-shaped supporting members 3, all these being conveniently made of mild steel.
  • a copper cathode lead 4 is clamped between the supporting member 3 and the base plate 2 and thus provi-des an electrical connection to the mercury cathode 5 which flows along the cell on the surface of the base plate 2.
  • Above ⁇ the mercury cathode 5 is the space occupied by the electrolyte 6.
  • the anode assembly is supported by the transverse steel anode frames 7 which in turn are carried on the side members 1.
  • the essential portion of the anode structure is a continuous titanium sheet 8 the underface of which is covered with an electrolytically deposited coating of platinum; this sheet is clamped at the edges between the side members 1 and ebonite spacers 15 lying on the base plate 2, so that it serves simultaneously as the anode and as a cover for the cell.
  • This sheet has at intervals transverse corrugations 9 which serve as channels wherein the chlorine liberated at the anode face collects and which lead to chlorine olf-takes 10. Bonded to the upper face of the titanium anode sheet 8 and covering the whole of its upper face between one corrugation and the next are a series of copper strips 11 which carry the current to the anode.
  • the portions of the copper strips which are positioned on the upper face of the titanium sheet are coterminous with the platinised area on the underface of the sheet.
  • the strips also extend beyond the titanium sheet as shown in FIGURE l for the indicated current connection.
  • this composite anode assembly is carried on the transverse anode frames 7.
  • the brine must be fed to a cell of this kind under considerable pressure and the copper-bonded titanium sheet which forms the actual cell cover is not of itself rigid enough to resist deformation under that brine pressure. Therefore a series of steel reinforcing strips 12, running longitudinally along the cell are inserted between the anode sheet 8 and the transverse anode frames 7 and secured to the latter lby means of clips or in any other convenient manner.
  • FIGURES 3 and 4 show, in ygreater detail, how the edges of the cell are sealed and the various constructional members assembled together.
  • FIGURE 3 which shows the anode edge lof the cell
  • the base plate 2 rests on the supporting member 3; above this are the ebonite spacing strip and rubber packing 16 and above these again are the platinised titanium anode 8 and its copper lead 11. All these members are clamped between the side frame 1 and the supporting member 3 by means of the bolts and nuts 13 and 14- respectively.
  • the base plate 2, the ebonite spacer 15 and the platinised face of the titanium anode sheet 8 define the actual cell space within which are contained the mercury 5 and the -brine 6.
  • FIGURE 4 which depicts the cathode edge of the cell, the arrangement is a little different since the copper lead 4 in this case makes contact with the base plate 2.
  • Other parts (similarly numbered in all the figures) serve the same purposes as already described in connection with FIGURE 3.
  • FIGURE 5 illustrates how the invention may be utilised in a more orthodox design of mercury cell utilising a lower rate of brine tiow; it depicts, in isometric projection, a transverse section across the cell.
  • the steel base plate 2 which bears the mercury cathode 5
  • the copper cathode lead 4 is held between the base plate 2 and the supporting member 3.
  • Titanium anode plates 19, platinised on the underface, are supported on titanium rods 20 which hold them below the brine surface and at the requisite distance from the mercury cathode 5.
  • the rods 20 pass through the cell cover 21 and are surrounded at their upper extremities by collars 22 which seal the orifice through which the rods traverse the cover. Copper anode leads 23 are clamped to the upper faces of the titanium rods 20 and collars 22 by means of the plates 24 and bolts 25.
  • the ⁇ brine is not fed under high pressure and does not ll all the cell space; the chlorine accumulates in the upper part of the cell and is taken olf by a pipe (not shown) at the end of the cell.
  • the present process for preparing chlorine Iand caustic alkali may be described as comprising the steps of providing an aqueous solution of an alkali metal chloride in an electrolytic cell, the cell having as the anode an operative surface of a metal selected from the group consisting Iof platinum, rhodium, alloys which yare largely rhodium and alloys which are largely platinum, and electrical conducting means within the cell operatively associated with the surface to lead current to said surface, the conducting means consisting essentially of titanium and thereafter supplying an electrolyzing current to the anode through the conducting means.
  • a cell for electrolyzing an aqueous solution of an alkali metal chloride comprising a substantially horizontal flowing mercury cathode and, positioned above and substantially parallel therewith, an anode which is a surface coating of la metal selected from the group consisting of platinum, rhodium, alloys which are largely platinum and alloys which are largely rhodium, carried on the underface of a sheet which consists essentially of titanium, said sheet constituting and functioning simultaneously as the cell cover, the anode support and the electrically con-ducting means which leads electrolyzing current to the anode, said cell also including a layer .of metal more conductive than titanium in contact with the upper face of said sheet and extending thereover so as to be at least coterminous with said surface coating.

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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)
  • Electrodes For Compound Or Non-Metal Manufacture (AREA)
US548032A 1957-12-17 1966-05-04 Mercury cathode cell with noble metaltitanium anode as cover means Expired - Lifetime US3318792A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB39272/57A GB911425A (en) 1957-12-17 1957-12-17 Improved anodes for electrolytic cells
GB871658 1958-03-18

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US (1) US3318792A (ru)
BE (1) BE573978A (ru)
CH (2) CH387002A (ru)
DE (2) DE1417193B2 (ru)
DK (1) DK107547C (ru)
FR (1) FR1217952A (ru)
NL (3) NL237215A (ru)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3410785A (en) * 1965-08-24 1968-11-12 Nat Res Corp Vacuum metallized electrode
US3445374A (en) * 1964-09-05 1969-05-20 Tsuyoshi Ishimatsu Alkali chloride electrolytic mercury cells
US3503799A (en) * 1966-05-19 1970-03-31 Ajinomoto Kk Method of preparing an electrode coated with a platinum metal
US3671415A (en) * 1969-09-02 1972-06-20 Ici Ltd Continuous lead-in core for an electrode assembly
US3676325A (en) * 1969-06-27 1972-07-11 Ici Ltd Anode assembly for electrolytic cells
US3755105A (en) * 1971-06-28 1973-08-28 G Messner Vacuum electrical contacts for use in electrolytic cells
US3853738A (en) * 1969-11-28 1974-12-10 Electronor Corp Dimensionally stable anode construction
US4029566A (en) * 1974-02-02 1977-06-14 Sigri Elektrographit Gmbh Electrode for electrochemical processes and method of producing the same
US4078988A (en) * 1974-02-02 1978-03-14 Sigri Elektrographit Gmbh Electrode for electrochemical processes and method of producing the same
US4330376A (en) * 1979-03-05 1982-05-18 Atlantic Richfield Company Process for inhibiting titanium corrosion

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL278152A (ru) * 1961-05-08
US3055811A (en) * 1961-05-08 1962-09-25 Universal Oil Prod Co Electrolysis with improved platinum plated titanium anode and manufacture thereof

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2503337A (en) * 1941-08-27 1950-04-11 Ici Ltd Electrolytic cells of the liquid electrode type
US2542523A (en) * 1941-08-27 1951-02-20 Ici Ltd Electrolysis of aqueous salt solutions in liquid cathode cells
US2872393A (en) * 1954-12-03 1959-02-03 Olin Mathieson Production of lithium hydroxide
US2955999A (en) * 1957-09-04 1960-10-11 Ionics Self-rectifying electrodialysis unit
US3236756A (en) * 1957-04-09 1966-02-22 Amalgamated Curacao Patents Co Electrolysis with precious metalcoated titanium anode

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2503337A (en) * 1941-08-27 1950-04-11 Ici Ltd Electrolytic cells of the liquid electrode type
US2542523A (en) * 1941-08-27 1951-02-20 Ici Ltd Electrolysis of aqueous salt solutions in liquid cathode cells
US2872393A (en) * 1954-12-03 1959-02-03 Olin Mathieson Production of lithium hydroxide
US3236756A (en) * 1957-04-09 1966-02-22 Amalgamated Curacao Patents Co Electrolysis with precious metalcoated titanium anode
US2955999A (en) * 1957-09-04 1960-10-11 Ionics Self-rectifying electrodialysis unit

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3445374A (en) * 1964-09-05 1969-05-20 Tsuyoshi Ishimatsu Alkali chloride electrolytic mercury cells
US3410785A (en) * 1965-08-24 1968-11-12 Nat Res Corp Vacuum metallized electrode
US3503799A (en) * 1966-05-19 1970-03-31 Ajinomoto Kk Method of preparing an electrode coated with a platinum metal
US3676325A (en) * 1969-06-27 1972-07-11 Ici Ltd Anode assembly for electrolytic cells
US3671415A (en) * 1969-09-02 1972-06-20 Ici Ltd Continuous lead-in core for an electrode assembly
US3853738A (en) * 1969-11-28 1974-12-10 Electronor Corp Dimensionally stable anode construction
US3755105A (en) * 1971-06-28 1973-08-28 G Messner Vacuum electrical contacts for use in electrolytic cells
US4029566A (en) * 1974-02-02 1977-06-14 Sigri Elektrographit Gmbh Electrode for electrochemical processes and method of producing the same
US4078988A (en) * 1974-02-02 1978-03-14 Sigri Elektrographit Gmbh Electrode for electrochemical processes and method of producing the same
US4330376A (en) * 1979-03-05 1982-05-18 Atlantic Richfield Company Process for inhibiting titanium corrosion

Also Published As

Publication number Publication date
CH417550A (de) 1966-07-31
DE1417193B2 (de) 1971-04-22
CH387002A (de) 1965-01-31
NL237215A (ru)
DK107547C (da) 1967-06-12
NL234316A (ru)
BE573978A (ru) 1959-06-17
NL125135C (ru)
DE1417193A1 (de) 1968-10-03
FR1217952A (fr) 1960-05-06
DE1417194A1 (de) 1968-10-03

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