US3507768A - Electrolytic cell - Google Patents

Electrolytic cell Download PDF

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Publication number
US3507768A
US3507768A US617646A US3507768DA US3507768A US 3507768 A US3507768 A US 3507768A US 617646 A US617646 A US 617646A US 3507768D A US3507768D A US 3507768DA US 3507768 A US3507768 A US 3507768A
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Prior art keywords
anode
electrolytic cell
bars
cathode
electrolyte
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US617646A
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English (en)
Inventor
Evgeny Ivanovich Adaev
Alexandr Vasilievich Blinov
Georgy Mikirtychevich Kamarian
Viktor Alexandrovich Novoselov
Vladimir Nikolaevich Suchkov
Leonid Markovich Yakimenko
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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
    • C25C7/00—Constructional parts, or assemblies thereof, of cells; Servicing or operating of cells
    • C25C7/005—Constructional parts, or assemblies thereof, of cells; Servicing or operating of cells of cells for the electrolysis of melts

Definitions

  • An electrolytic cell comprises a hollow annular anode assembled from a plurality of spaced circumferentially arranged bars, the anode defining a cavity in which an anode cooler penetrates.
  • the anode is surrounded by a closed cathode and the anode cathode and anode cooler are incorporated in a lined tank, the dimensions of the anode and the lined tank, the lining thickness and the cooler parameters being selected so as to constantly maintain in the course of electrolytic cell operation a heat insulating garnissage layer at least on the entire inner surface of the tank.
  • This invention relates to cells for the production of sodium by the electrolysis of sodium chloride in a fused bath of halide electrolytes.
  • a refractory brick-lined tank which houses an anode assembled from bars and a cathode that surrounds the anode assembly (cf. Alabishev et al., Sodium and Potassium, Goskhimizdat, 1959).
  • a screen diaphragm afiixed to a dome which is located above the anode and cathode and serving for collecting and discharging the sodium and chlorine liberated when the fused salt bath undergoes electrolysis in the course of cell operation.
  • the principal disadvantage stems from the fact that the temperature of the electrolyte rises above the permissible level, thereby causing an interruption or even complete termination of the process of sodium and chlorine liberation.
  • Another adverse factor responsible for a decreased yield of the electrolysis products is the onset of unwanted eddies in the electrolyte, the most pronounced deleterious elfect being produced by the eddies arising in the vicinity of the upper butt ends of the anode graphite bars and obstructing the inflow of the electrolyte into the central channel of the anode.
  • the known electrolytic cells for the production of sodium also suffer from the disadvantage in that the working face of the anode assembly must be machined to obtain the desired dimensions.
  • the machining of graphite rods involves the removal of the surface layer obtained in the course of manufacturing and graphitizing the graphite rods and results in a shorter anode life as well as in a rapid increase of the interpole gap.
  • This object has been accomplished in an electrolytic cell intended primarily for the production of sodium and chlorine from molten halide electrolytes, in which a bar anode assembly and a closed cathode surrounding the anode are disposed in a tank, wherein, according to the invention, the dimensions of the tank and anode, the thickness of lining and the parameters of the anode cooler are selected so as to render it possible to maintain in the bath, in the course of cell operation, adequate surface conditions (garnissage), at least over the entire surface of the bath walls.
  • Use can likewise be made of anode bars which are trapezoidal in the cross-section and chamfered on the outside and inside in the top part.
  • FIG. 1 is a longitudinal section of the electrolytic cell
  • FIG. 2 is a sectional view of the electrolytic cell taken along line IIII of FIG. 1.
  • the electrolytic cell comprises a tank 1 formed by a cylindrical steel shell (FIGS. 1 and 2) lined with fireclay brick 2.
  • a cathode which consists of perforated steel cylinder 3 held in place by two steel plates 4 welded to it, the plates passing through the side walls of the tank and resting on brackets 5.
  • the anode is constituted of prismatic graphite bars 6, which are trapezoidal in cross section. Graphite is formed into this shape in the course of manufacturing the bars so as to preserve a firm, unmachined layer on the working surface of the anode bars.
  • the bars are disposed within the cathode at equal distances from it and form a hollow annular anode having appropriate clearances between adjoining bars. Screws 7 are screwed into the bottom of the bars. Bars 6 of the anode assembly rest on contactor unit 8, in which provision is made for cooler 9, which partly protrudes into the anode cavity and is sealed with concrete layer 10 containing a graphite filler and having a coeflicient .of thermal expansion that is nearly equal to that of bars 6 of the anode assembly. In each bar 6, the top has an inner chamfer 11 and an outer chamfer 12.
  • the inner chamfers form an expansion in the upper part of the anode chamber, while the outer chamfers are instrumental in inscreasing the distance between the anode and cathode.
  • the cathode provision is also made for top and bottom chamfers on the cathode side facing the anode.
  • annular trough 16 Suspended from frame 14 of the electrolytic cell bv means of steel ties 1-5 is an annular trough 16, which mounts diffuser 17. Cylindrical screen 18 rigidly affixed to annular trough 16 is disposed in the space between the anode and cathode. The screen separates the anolyte from the catholyte layer, thereby preventing contact between the sodium and chlorine.
  • Top plate 19 of the electrolytic cell is furnished with a mechanism for centering screen 18 in the interelectrode gap in the course of cell operation.
  • the anode bars are shaped to the desired form at the manufacturing plant by a process involving extrusion through a die of an appropriate section, so that the users of anode bars may dispense with machine tools for machining the surface of anode bars and have the advantage of employing the anode bars with the most dense layer of the working surface left intact, which fact results in longer anode life.
  • the bars are mounted in the electrolytic cell consecutively one after another, the cathode of the cell serving as a templet to which the anode bars are adjusted via spacers that determine the interelectrode gap.
  • the Wall thickness, inside diameter and height of the cell shaft should be estimated on the basis of optimum results of the electrolytic cell operation when the current efficiency amounts to 80% These results are obtained when the following ratio holds:
  • D is the diameter of electrolytic cell shaft, in meters
  • H is the height of electrolytic cell shaft, in meters
  • I is the cell load, in amperes.
  • the thickness of the electrolytic cell walls is selected to conform with the load applied to the given cell.
  • the electrolytic cell of the present type operates as follows.
  • the cell bath contains a molten electrolyte which fills the cell shaft almost to the top.
  • the bath dimensions, lining thickness and the parameters of the cooler disposed within the anode bottom are selected so as to constantly provide, in the course of electrolytic cell operation, garnissage over the entire surface of the side walls of the shaft and a crust on the electrolyte surface.
  • the crust and garnissage are heat-insulating layers that have the property of varying automatically their thickness in response to an increase or decrease in the amount of excessive heat in the electrolytic cell, thereby ensuring a corresponding increase or decrease in the amount of the heat eliminated from the electrolytic cell when the temperature of the electrolyte experiences a slight variation.
  • Direct current flowing through the electrolytic cell enters the anode via lead layer 13 cast to fill the space between cooler 9 and the wall of contact unit 8.
  • the anode of the present electrolytic cell is made hollow and houses in the bottom part a cooler intended for eliminating the excessive heat.
  • the anode cavity is sealed together with the cooler by graphitefilled concrete whose coeflicient of thermal expansion is close to that of graphite.
  • Current supply to the cathode is effected via plates 4 welded to it.
  • Diffuser 17 directs the chlorine into a chlorine chamher, from whence the chlorine leaves the cell via a chlorine pipeline.
  • the electrolyte is maintained at a temperature of approximately 600" C. in the course of electrolytic cell operation.
  • the temperature in the cell becomes excessive, garnissage on the shaft side walls and the crust on the electrolyte surface become thinner, this process resulting in the appearance of free-from-crust areas on the electrolyte surface or, in the limiting case, in the complete freedom of the electrolyte surface from the crust.
  • Crust thinning is conducive to an increased heat transfer to the ambient medium.
  • the desired gap between the anode and the cathode faces is obtained due to the fact that the anode bars of trapezoidal cross-section are assembled to form the anode by a technique involving the use of temporary spacers between the bars being assembled and the cathode face.
  • anode bars in which the facets that form the working face of the anode undergo no machining and retain the characteristics conferred on them by moulding and graphitizing in the course of manufacture.
  • Preservation of the external layer of the anode bars makes it possible to obtain the anode face noted for its durability under service conditions, which fact accounts for longer life of the electrolytic cells of the present type due to lower wear of the anode face.
  • inner and outer chamfers which are instrumental in diminishing the surface of the top butt ends of the anode bars which cause the onset of deleterious eddies in the electrolyte. Due to the chamfers, electrolyte flow into the central channel of the anode is more steady and no eddies arrise.
  • the outer chamfers provide for an increased volume of the space between the anode and screen (diaphragm) at the upper end of the anode thereby reducing the pressure of chlorine bubbles and decreasing the extent to which chlorine penetrates through the screen into the cathode chamber.
  • the presence of the outer chamfers on the top ends of the anode bars facilitates the insertion of a screen into the interelectrode gap in the course of cathode dome replacement.
  • Heating causes no deterioration of the anode bars because use is made of graphite-filled concrete to seal the anode bars in the hearth, the coefficient of thermal expansion of this sealing material being close to that of graphite.
  • T o attain a more eflicient heat elimination from the anode, use is made of the cooler disposed in the anode cavity.
  • the cathode-to-screen voltage drop is maintained in the 1.5 to 2.2 v. range to obtain the maximum current efficiency; voltage drop control is elfected by means of the screen centering mechanism.
  • An electrolytic cell for the production of sodium and chlorine from fused halide electrolytes which comprises a hollow annular anode assembled from a plurality of circumferentially arranged bars; a closed cathode Surrounding said anode; an anode cooler at least partly inserted into said anode; and a lined tank incorporating said anode, said cathode, and said anode cooler, the dimensions of said anode and said lined tank, lining thickness and cooler parameters being selected so as to constantly maintain, in the course of electrolytic cell operation, a heat insulating garnissage layer at least on the entire inner surface of the tank.

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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)
  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
US617646A 1951-01-28 1967-02-21 Electrolytic cell Expired - Lifetime US3507768A (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE19511558726 DE1558726B2 (de) 1951-01-28 1951-01-28 Elektrolysierzelle
US61764667A 1967-02-21 1967-02-21
GB8706/67A GB1185481A (en) 1951-01-28 1967-02-23 Electrolytic Cell for the Electrolysis of a Molten Electrolyte.
DEA0055248 1967-03-23

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US3507768A true US3507768A (en) 1970-04-21

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US617646A Expired - Lifetime US3507768A (en) 1951-01-28 1967-02-21 Electrolytic cell

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US (1) US3507768A (enrdf_load_stackoverflow)
DE (1) DE1558726B2 (enrdf_load_stackoverflow)
GB (1) GB1185481A (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2554462A1 (fr) * 1983-11-08 1985-05-10 Degussa Dispositif et procede pour l'electrolyse ignee d'halogenures de metaux alcalins
US4647355A (en) * 1984-11-09 1987-03-03 Hiroshi Ishizuka Apparatus for molten salt electrolysis
US5904821A (en) * 1997-07-25 1999-05-18 E. I. Du Pont De Nemours And Company Fused chloride salt electrolysis cell
US6409895B1 (en) 2000-04-19 2002-06-25 Alcavis International, Inc. Electrolytic cell and method for electrolysis
WO2015024030A2 (en) 2013-08-16 2015-02-19 Csir Molten salt electrolysis apparatus and process

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2418083C2 (ru) * 2009-06-19 2011-05-10 Учреждение Российской академии наук Институт высокотемпературной электрохимии Уральского отделения Российской академии наук Электролизер для рафинирования свинца в расплаве солей

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2213073A (en) * 1937-10-21 1940-08-27 Robert J Mcnitt Furnace electrode
US2390114A (en) * 1939-11-18 1945-12-04 Robert J Mcnitt Electrolysis of fused baths
US2990347A (en) * 1958-06-06 1961-06-27 Du Pont Preparation of carbon tetrafluoride
US3334040A (en) * 1963-10-02 1967-08-01 Pittsburgh Plate Glass Co Bonding electrically conductive elements

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2213073A (en) * 1937-10-21 1940-08-27 Robert J Mcnitt Furnace electrode
US2390114A (en) * 1939-11-18 1945-12-04 Robert J Mcnitt Electrolysis of fused baths
US2990347A (en) * 1958-06-06 1961-06-27 Du Pont Preparation of carbon tetrafluoride
US3334040A (en) * 1963-10-02 1967-08-01 Pittsburgh Plate Glass Co Bonding electrically conductive elements

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2554462A1 (fr) * 1983-11-08 1985-05-10 Degussa Dispositif et procede pour l'electrolyse ignee d'halogenures de metaux alcalins
DE3340294A1 (de) * 1983-11-08 1985-05-23 Degussa Ag, 6000 Frankfurt Vorrichtung und verfahren zur schmelzflusselektrolyse von alkalimetallhalogeniden
DE3340294C2 (de) * 1983-11-08 1985-09-19 Degussa Ag, 6000 Frankfurt Vorrichtung und Verfahren zur Schmelzflußelektrolyse von Alkalimetallhalogeniden
US4647355A (en) * 1984-11-09 1987-03-03 Hiroshi Ishizuka Apparatus for molten salt electrolysis
US5904821A (en) * 1997-07-25 1999-05-18 E. I. Du Pont De Nemours And Company Fused chloride salt electrolysis cell
US6409895B1 (en) 2000-04-19 2002-06-25 Alcavis International, Inc. Electrolytic cell and method for electrolysis
WO2015024030A2 (en) 2013-08-16 2015-02-19 Csir Molten salt electrolysis apparatus and process

Also Published As

Publication number Publication date
DE1558726C3 (enrdf_load_stackoverflow) 1974-04-18
DE1558726B2 (de) 1973-09-06
GB1185481A (en) 1970-03-25
DE1558726A1 (de) 1970-04-23

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