US3583898A - Anode assembly for electrolytic cell - Google Patents

Anode assembly for electrolytic cell Download PDF

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Publication number
US3583898A
US3583898A US788212A US3583898DA US3583898A US 3583898 A US3583898 A US 3583898A US 788212 A US788212 A US 788212A US 3583898D A US3583898D A US 3583898DA US 3583898 A US3583898 A US 3583898A
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United States
Prior art keywords
cavities
alloy
base
shell
seal
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Expired - Lifetime
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US788212A
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English (en)
Inventor
Umberto Giacopelli
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Solvay SA
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Solvay SA
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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
    • 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 a new structure of the anodecarrying base for electrolytic cells of the type having a series of parallel electrodes designed in particular for the electrolysis of aqueous solutions of halides of alkaline metals and provided with means for feeding electric current, sealing means for the electrodes and protection against corrosion.
  • the anodic plates which are generally graphite, are fixed vertically in a base of reinforced concrete by means of a layer of lead assuring electric contact and coated with a layer of cement and/or a layer of asphalt sometimes itself covered with a layer of cement.
  • the current conducting bars are embedded in the layer of lead perpendicularly to the anodic plates.
  • the asphalt layer is subject to a certain softening which can result in its displacement.
  • the asphalt If the asphalt is in contact with the electrolyte, it can, by reaction with the halogen formed on the anodes, produce halogenated organic compounds which can contaminate the halogen or form muds which seal the diaphragm.
  • anodic assembly for electrolytic cells comprising an anode-carrying base provided with parallel cavities extending substantially throughout the cell and each including a current conducting 'bar extending through a side of the base, the bottoms of a row of vertical anodic plates resting on the bar and a bedding or sealing alloy having a low melting point, characterized in that at least the part of the base which is in direct contact with the electrolyte in the course of the electrolysis is formed of an insulating and chemically inert material while in each cavity the sealing alloy is protected from attack by the electrolyte and the products of electrolysis by a synthetic resin which is cast on the said alloy and is set in situ by the effect of heat to form an easily removable elastic joint which assures at the top of each cavity a fluid tight seal between the anodic plates and the insulating and inert material of the base.
  • FIGS. 1 to 5 are schematic cross sections illustrating different embodiments of an anode-carrying base in accordance with the invention
  • FIG. 6 is a top plan view of one particular embodiment of a complete anodic assembly
  • FIGS. 7 and 8 are respectively a cross section and a longitudinal section of a cell equipped with such anodic assembly, and;
  • FIGS. 9 and 10 are schematic partial sections showing electrical connection of adjacent cavities.
  • the shell 1 of the anodecarrying base is formed of an insulating and chemically inert material capable, for example, of resisting wet chlorine and chlorine-containing brine up to C. as, for example, a polyester resin reinforced with glass fibers.
  • the same inert material constitutes not only the shell of the base but also its internal structure 2 of honeycomb type with cells or cavities which assures a rigidification of the assembly without internal stresses. If desired, the rigidity of the structure can be still further improved by introducing into the cells a foam of synthetic resin 3 which is expanded and solidified in situ.
  • the cellular structure has the advantage of permitting a circulation of air in the base itself, under the shell and around and under the parallel cavities, which assures the cooling of the base of the anodes during electrolysis.
  • Adherence between the concrete 4 and the shell 1 is assured by anchoring projections 7 which extend inwardly from the inner surface of the shell and into the concrete 4.
  • the parallel cavities 8, which are seen in cross section, are formed by recesses in the shell of insulating and inert material which thus forms partitions between the cavities.
  • the cavities 8 are formed by the inert shell, while their lower parts are formed of refractory and acid resisting cement 9 which is cast in the inverted shell previously provided with removable molds placed in each cavity.
  • the reinforced concrete 4 is put in place after the refractory cement has set.
  • the two materials are sparated by a layer 10 (FIGS. 7 and 8) of an impermeable and inert material such as synthetic resin.
  • the shell 1 does not form the cavities 8 but presents a basin with a flat bottom on which rests, sideby-side, a series of tubes 11 of insulating and chemically inert material, for example polyester resin reinforced with glass fibers. These tubes are joined with one another and are provided at their tops with longitudinal slots i12 for the introduction of the anodic plates (not shown).
  • the tubes traverse one of the lateral sides of the base and extend outside in order to protect from corrosion the current conducting bars which they are designed to shield. Indeed, in the four other modes of construction illustrated in FIGS. 1, 2, 3 and 5 the extremities of the copper bars 13, visible in the plan view of FIG. 6, are at the mercy of possible seepage of the electrolyte.
  • the interior of the parallel cavities 8 is advantageously covered with a lining 14 of plastic material resistant to heat and nondeformable, such as an epoxy resin preferably reinforced by glass fibers or other reinforcing material.
  • FIG. 6 shows in plan a complete anodic assembly, that is to say, a base provided with anodic plates 15, the subjacent current conducting bars 13 of which only the extremities are visible and the sealing alloy 18 (FIG. 7) protected from corrosion by elastic joints 19.
  • FIG. 6 shows only six parallel cavities.
  • Each anode can be formed of any appropriate material which is a good conductor of electricity such as graphite, magnetite, titanium or its alloys coated with precious metals or compounds thereof.
  • the parallel cavities are electrically connected by means of bridge 16 at the side of the base opposite that from which the ends of the bars 13 protrude.
  • the electric coupling can likewise be provided, as illustrated in FIG. 9, by a metallic conductor 40 for example of titanium or copper coated with titanium, in the form of an inverted U spanning the partition separating the two cavities to be connected and fixed in place by their two extremities embedded in the sealing alloy on opposite sides of the partition.
  • a metallic conductor 40 for example of titanium or copper coated with titanium, in the form of an inverted U spanning the partition separating the two cavities to be connected and fixed in place by their two extremities embedded in the sealing alloy on opposite sides of the partition.
  • the electrical coupling can also be provided, as illustrated in FIG. 10, by a removable conductor 41 temporarily connecting two bolts 42 of conductive metal disposed on opposite sides of the sparating partition, the head 43 of'each bolt being embedded inthe sealing alloy 18' and the thread, coated with titanium, emerging from the alloy and receiving nuts 44 for securing the conductor.
  • the electrical couplings are located at the ends of the cavities opposite those at which the ends of the bars extend. In FIGS. 9 and 10 the seal 19 has been omitted.
  • FIGS. 7 and 8 show respectively a cross section and a longitudinal section of a diaphragm cell equipped with the refractory cement base shown in FIG. 5.
  • the anodes are put in place in the following manner: After having introduced into the parallel cavities, the copper bars 13, the shape of Which corresponds to that of the bottom of the cavities, and possibly the metallic conductors for electrically coupling each pair of cavities, the orifices 17 through which the bars extend through the side of the base are carefully closed and an alloy 18 having a low melting point and low shrinkage on solidification, such as the lead-bismuth alloy described in my application Ser. No. 605,247, is poured into the cavities. The alloy 18 partially solidifies. An electric current of appropriate intensity is then applied to' the'free ends of two bars 13 which are electrically coupled in such manner as to bring the alloy back to its melted state and raise its temperature to a selected value (approximately 250 C.). The previously coppered and tinned extremities of the graphite plates 15 are then placed in the melted alloy 18 so as to come into contact with the bars 13. This procedure is then repeated on the adjacent pair of parallel cavities.
  • the surfaces of the graphite, the alloy and the partitions are advantageously coated with an adhesive undercoating, for example an epoxy resin, which improves the adherence between these materials and the polyvinyl chloride.
  • the parallel cavities can have any desired section but are advantageously narrowed at the top as can be seen in the cross sectional views in such manner as to retain firmly between their lips the elastic joint and to prevent its detachment or accidental displacement.
  • the metallic cathode case 20 of which the cathode elements 21 which are made of wire netting or perforated sheet metal support a diaphragm of asbestos fibers not shown).
  • the cathode elements 21 are advantageously tapered at the base as seen in FIG. 7 in such manner as to avoid local. thickening of the diaphragm when it is deposited and an anode-diaphragm contact due to local enlargement thereof in the course of the electrolysis.
  • the cathode case 20 is provided with conduits 22 and 23 for the evacuation of the lye and the hydrogen respectively, a safety conduit 24 and the cathode current lead 25. Fluid tightness between the base 1 and the casev 20 on the one hand and between the case 20 and the cover 26 on the other hand is assured by gaskets 27 and 28 resistant to the chlorine-containing brine.
  • the cover 26 is formed of polyester reinforced with glass fibers or of polypropylene reinforced with perforated sheet metal. It carries a brine inlet 29, a chlorine outlet 30 and a level indicator tube 31.
  • a member 32 in the form of a comb resting on the electrodes maintains a constant anode-cathode spacing.
  • the spaces 33 for the cathodes have their edges substantially parallel.
  • the spaces 34 for the anode plates are of trapezoidal form, larger at the base than at the top, so that when the anodes are new only the extremities of the teeth 35 are inserted between the electrodes. As they are used up, the graphite plates engage further in these spaces which are provided for them.
  • This device which avoids all anode-cathode short circuits, can be formed of any material which resists the electrolyte and the products of electrolysis and which has sntficient rigidity at the operating temperature of the cell. Its density is preferably greater than that of the electrolyte so that the comb 32 does not float on the surface of the electrolyte. Polyester resin and polyvinyl chloride are particularly suitable as materials for its construction.
  • connection of the parallel cavities by pairs permits melting of the alloy and the setting in situ of its protective joint by the heating eifect obtained by the passage of electric current.
  • the elasticity of the joints set in situ according to the present invention permits (after emptying the cell) removing them like simple stoppers. This provides the possibility either of replacing any defective anodes or of renewing all of the anodes without breaking any part of the base.
  • An anode assembly for an electrolytic cell comprising a base having a plurality of parallel anodereceiving cavities open at their tops and separated by partitions, a current conducting bar lying in each of said cavities and extending through a side of the base, a low melting point sealing alloy overlying said bar in each said cavity, vertical anode plates having their lower edge portions extending into said alloy in each said cavity and resting on said bar, at least those portions of said base exposed to the electrolyte of said cell being formed of an insulating and chemically inert material, and a seal of synthetic resin set in situ in each said cavity overlying said alloy to form an easily removable plastic joint providing a hermetic seal between said anode plates and adjacent portions of said base.
  • thermostable resin having a low coefiicient of thermal expansion is an epoxy resin.
  • said electrical connection comprises an inverted U-shaped conductor straddling the partition between said adjacent cavities and having its opposite ends embedded in said sealing alloy in said cavities.
  • said electrical connection comprises metallic bolts having heads embedded respectively in the sealing alloy in said adjacent cavities and a metallic conductor removably secured to said bolts to provide an electrical connection between them.

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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 Metals (AREA)
  • Prevention Of Electric Corrosion (AREA)
US788212A 1968-01-03 1968-12-31 Anode assembly for electrolytic cell Expired - Lifetime US3583898A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
BE52917 1968-01-03
BE708888 1968-01-03

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US3583898A true US3583898A (en) 1971-06-08

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US788212A Expired - Lifetime US3583898A (en) 1968-01-03 1968-12-31 Anode assembly for electrolytic cell

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US (1) US3583898A (US08066781-20111129-C00013.png)
BE (1) BE708888A (US08066781-20111129-C00013.png)
CH (1) CH495779A (US08066781-20111129-C00013.png)
DE (1) DE1813117A1 (US08066781-20111129-C00013.png)
FR (1) FR1599572A (US08066781-20111129-C00013.png)
NL (1) NL6900025A (US08066781-20111129-C00013.png)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3911565A (en) * 1974-05-24 1975-10-14 Ppg Industries Inc Method of protecting current leads in electrolytic cells
US3954593A (en) * 1971-08-26 1976-05-04 Basf Wyandotte Corporation Method for attaching anode to electrolytic cell bottom and device therefore
US3975255A (en) * 1974-02-27 1976-08-17 Olin Corporation Inter-electrode spacing in diaphragm cells

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3954593A (en) * 1971-08-26 1976-05-04 Basf Wyandotte Corporation Method for attaching anode to electrolytic cell bottom and device therefore
US3975255A (en) * 1974-02-27 1976-08-17 Olin Corporation Inter-electrode spacing in diaphragm cells
US3911565A (en) * 1974-05-24 1975-10-14 Ppg Industries Inc Method of protecting current leads in electrolytic cells

Also Published As

Publication number Publication date
DE1813117A1 (de) 1969-08-14
CH495779A (fr) 1970-09-15
BE708888A (US08066781-20111129-C00013.png) 1968-07-03
NL6900025A (US08066781-20111129-C00013.png) 1969-07-07
FR1599572A (US08066781-20111129-C00013.png) 1970-07-15

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