US3118827A - Fused salt electrolysis cell - Google Patents

Fused salt electrolysis cell Download PDF

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Publication number
US3118827A
US3118827A US108039A US10803961A US3118827A US 3118827 A US3118827 A US 3118827A US 108039 A US108039 A US 108039A US 10803961 A US10803961 A US 10803961A US 3118827 A US3118827 A US 3118827A
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US
United States
Prior art keywords
anode
cathode
electrolyte
cell
collector
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 - Lifetime
Application number
US108039A
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English (en)
Inventor
Stanley E Eckert
Francis J Ross
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.)
EIDP Inc
Original Assignee
EI Du Pont de Nemours and Co
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority to NL136135D priority Critical patent/NL136135C/xx
Priority to NL278057D priority patent/NL278057A/xx
Application filed by EI Du Pont de Nemours and Co filed Critical EI Du Pont de Nemours and Co
Priority to US108039A priority patent/US3118827A/en
Priority to CH504862A priority patent/CH417123A/de
Priority to GB16644/62A priority patent/GB959636A/en
Priority to DK202262AA priority patent/DK104863C/da
Priority to FR896538A priority patent/FR1322529A/fr
Priority to DEP29336A priority patent/DE1184966B/de
Priority to BE617283A priority patent/BE617283A/fr
Priority to AT364262A priority patent/AT241835B/de
Application granted granted Critical
Publication of US3118827A publication Critical patent/US3118827A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • C25C3/00—Electrolytic production, recovery or refining of metals by electrolysis of melts
    • C25C3/02—Electrolytic production, recovery or refining of metals by electrolysis of melts of alkali or alkaline earth metals
    • 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

  • FIGlA INVENTORS STANLEY E. EOKERT Q FRANCIS J. ROSS BYWxSQW M101,
  • This invention relates to a fused salt electrolytic cell for the production of a molten metal having a density below the density of the molten electrolyte and more particular-1y to a cell for the production of sodium involving a plurality of anode and cathode elements.
  • Patent 2,315,443 (March 30, 1943), and 2,390,114 (December 4, 1945), accelerated circulation in the cathode zone by creating temperature differentials in the cell.
  • Anolyte circulators such as that of Hulse et al., US. Patent 2,194,444 (March 19, 1940), were employed principally to prevent freezing of electro lyte in the upper part of the cell and to assist in chlorine removal.
  • the aforesaid catholyte circulating devices prevented excessive calcium deposition and were of some value in cells containing a single cathode-anode element, short circuiting due to solid deposition has remained a problem.
  • a circulator conduit in the collector-assembly of a fused salt cell disposed in such fashion as to permit electrolyte from the anodic product collector to pass downward into the catholyte zone.
  • the desired results are obtained in a fused salt sodium cell containing at least two and preferably four cathode-anode elements by use of a vertically disposed circulating conduit.
  • This conduit allows substantially gas-free electrolyte from a point somewhat above the roof of the sodium collecting channel in the chlorine collector dome to flow downward to a point which is either at, or below, the electrolyte-molten sodium interface in the catholyte zone.
  • Preferred results are obtained when the circulator discharges in the electrolytemolten sodium interface area, but the invention also functions when the circulator extends downward to a point not lower than the bottom of the cathode.
  • FIGURE 1 is a vertical cross-section of a sodium cell having four anode-cathode elements showing the collector assembly and the catholyte circulator conduit. This section is at II of FIGURES 2 and 3.
  • FIGURES 1A and 1B are fragmentary vertical sections of alternate circulators drawn on the same scale as FIG- URE 1.
  • FIGURE 2 is a horizontal section showing the collector assembly at Ii-II of FIGURE 1.
  • FIGURE 3 is a horizontal section of the cell of FIG- URE 1 at llIIi'I.
  • the sodium cell comprises a steel shell or containing vessel 12 lined with a refractory ll. symmetrically arranged therein are four cylindrical graphite anodes 7 7 '7 and 7
  • a steel cathode assembly comprises four cylindrical cathodes, 9 9 9 and 9 and the supporting cathode arms 10 and 101
  • the approximate level of arms 10 and 10 is indicated schematically in FIGURE 1 by dotted lines.
  • the cylindrical anode-cathode elements comprise a central graphite or carbon anode and a surrounding steel cathode.
  • Cylindrical permeable diaphragms 3 8 8 and 8 are supported substantially midway in the electrolytic zone between anode and cathode. In the operating cell, these anode-cathode elements are immersed in fused electrolyte and the diaphragms separate the central anode products from the peripheral cathode products and define the borders of the anolyte and catholyte zones.
  • the collector assembly is mounted above the electrode elements and comprises a molten sodium collector channel 5 having an upper roof 6 pierced by cylindrical diaphragm supporting chimneys 2 2 2 and 2 Surmounting sodium channel roof 6 is the anodic product dome 4 which receives the chlorine charged anollyte ascending through the diaphragm supporting chimneys.
  • Sodium leaves the collector channel 5 by ascending riser pipe 3 through which it is removed from the cell.
  • the roof of the sodium channel slopes upward to the riser pipe to assure smooth flow of sodium thereto, but this is not shown in the schematic drawings.
  • the catholyte circulator conduit 1 is usually :located in the center of the dome and is vertically disposed so that it passes downward through the horizontal axis of the roof 6 of the sodium collector channel 5.
  • the conduit is preferably a cylindrical pipe with a capped bottom 17 whose vertical Wall is pierced with at least one and usually four exit ports 16 as indicated in the schematic drawing of FIGURE 1.
  • FIGURE lA differs from the circulator of FIGURE 1 only in that it descends into the catholyte area to a point above the level of the cathode bottoms where its vertical wall is pierced with one or more exit ports 16 just above the capped bottom 17.
  • FIGURE 1B shows another alternate deep catholyte circulator having exit ports 16 similar to 1 above the level of the lower edge of the diaphragm-supporting chimneys, means for restricting the flow of electrolyte consisting of a constriction or bafile 18 just below these ports as well as lower exit ports 16 located just above the level of the bottom of the conduit 17.
  • the bottom of the circulator conduit of FIGURE 13 may be located at any point between the level of the vertical midpoint of the cathode and the cathode bottoms.
  • side exit ports in the circulator conduit as shown in the drawings are preferred, the circulator exit may also take the form of an open bottom to the conduit.
  • the cell is substantially filled with the molten salt electrolyte.
  • Anolyte circulation indicated by arrows in FIGURE 1 is assisted by upward flow of chlorine gas bubbles from the anodes 7 thru the diaphragm-supporting chimneys 2 into the chlorine collector dome 4 where chlorine escapes through conduit 19. This movement raises the molten salt level 14 in the chlorine dome above the cell level 13.
  • Catholyte circulation also indicated by arrows is assisted by the normal upward flow of molten sodium from the active inner surface of the cylindrical cathodes 9. Down flow of catholyte normally takes place by natural diffusion around the outer inactive surface of the cathodes.
  • the catholyte circulator of this invention increases catholyte circulation by allowing an effective stream of electrolyte from the chlorine collector dome 4 to flow downward into the central catholyte zone. Prior to the development of the catholyte circulator of this invention, anolyte in the chlorine collector zone had substantially no opportunity to circulate.
  • Circulation rates through the catholyte circulator of this invention influence the results obtained and should be adjusted to secure optimum results for a given cell.
  • the rate of circulation is controlled in part by the diameter and length of the conduit. It may also be modified for a given conduit size by adjusting the height of the circulator pipe above the roof of the sodium collector channel within the zone of the hydraulic head difference between the electrolyte level inside the chlorine collecting dome 14 and the level outside the dome 13. This differ- .ence may be in the range 4 to 6 inches depending on cell design and operating amperage.
  • the circulation rate may also be adjusted by restricting the discharge of the circulator by controlling the size of outlet orifices 16 and the baifie 18.
  • the one or more discharge orifices are preferably designed to direct the discharged electrolyte flow parallel with and just below the molten metal interface boundary.
  • the circulating current is fundamentally a result of gravity, the natural circulation of the cell and density differences due to normal temperature variations. No impeller is employed.
  • Sodium cells equipped .with the novel catholyte circulator of this invention show reduced depletion of sodium ion in the catholyte zone since they provide an accelerated circulation of fresh bath. These cells also show a decrease in calcium deposition and a consequent increase of diaphragm life. This reduces both the expense of diaphragm replacement and loss of production during the replacement process.
  • cells with the catholyte circulator show an improvement in current efficiency over that obtained with similar cells without the circulator. It has been demonstrated that unusually good results are obtained with the preferred circulator alternate in which the exit ports from the bottom of the conduit direct flow in the plane of sodium-electrolyte interface and are located just below this interface as shown in FIGURE 1.
  • electrolyte circulation must not be excessive.
  • circulation through the catholyte circulator should be in the magnitude of about one to sixty gallons per minute.
  • the preferred rate is one to twenty gallons per minute.
  • the preferred rate is in the range 10 to 60 gallons per minute.
  • the optimum circulation rate will depend on the type and size of the sodium cell and may be readily determined by experiment.
  • the catholyte circulator is not limited to the four-anode fused salt sodium cell which has been used to exemplify the invention. It may be used with cells having two or three anode-cathode elements or with cells having a larger number of electrode pairs. In the latter cells, it may be desirable to employ several catholyte circulator conduits to facilitate circulation.
  • This invention is generally applicable to electrolytic cells involving the electrolysis of fused salt m'stures wh re the metal product of the electrolysis will float on the cell bath and both the anodic and cathodic products are collected at the top of the cell.
  • a fused salt Downs-type electrolytic cell for the production or" a molten metal having a density lower than that of the fused salt electrolyte and a gaseous anode product, said cell comprising (a) at least two vertically disposed anode-cathode assembiies, each comprising an anode, a cathode and a diaphragm disposed therebetwecn and separating the electrolyte into anolyte and catholytc zones; and
  • a collector assembly mounted above said anodecathode assemblies comprising a submerged cathode product collector, a surmounting anode product collector and chimneys leading upwards from the anolyte zones of the cell and opening into said anode product collector, said chimneys defining vertical passageways for the upward flow of electrolyte and anode product from said anode zones into said anode product collector, said cathode product collector comprising a generally horizontally disposed roof wherein the conduit to permit flow of electrolyte from 10 the anode product collector into the catholyte zone is provided with a discharge for the electrolyte at about the level of the upper ends of the cathodes.
  • the conduit to permit flow of electrolyte from the anode product collector into the catholyte Zone is provided with a discharge for the electrolyte at about the 5 level of the lower ends of the cathodes.

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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)
US108039A 1961-05-05 1961-05-05 Fused salt electrolysis cell Expired - Lifetime US3118827A (en)

Priority Applications (10)

Application Number Priority Date Filing Date Title
NL136135D NL136135C (enrdf_load_stackoverflow) 1961-05-05
NL278057D NL278057A (enrdf_load_stackoverflow) 1961-05-05
US108039A US3118827A (en) 1961-05-05 1961-05-05 Fused salt electrolysis cell
CH504862A CH417123A (de) 1961-05-05 1962-04-26 Schmelzflusselektrolysezelle zur Erzeugung von geschmolzenem Metall und Verfahren zu ihrem Betrieb
GB16644/62A GB959636A (en) 1961-05-05 1962-05-01 Electrolytic chemical apparatus and process
DK202262AA DK104863C (da) 1961-05-05 1962-05-03 Elektrolysecelle.
FR896538A FR1322529A (fr) 1961-05-05 1962-05-04 Pile électrolytique à conduit de circulation de l'électrolyte
DEP29336A DE1184966B (de) 1961-05-05 1962-05-04 Schmelzflusselektrolysezelle nach Downs zur Herstellung von geschmolzenem Metall, insbesondere von Natrium
BE617283A BE617283A (fr) 1961-05-05 1962-05-04 Pile électrolytique à conduit de circulation de l'électrolyte
AT364262A AT241835B (de) 1961-05-05 1962-05-04 Elektrolysezelle und Verfahren zur Erzeugung von Natrium und Chlor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US108039A US3118827A (en) 1961-05-05 1961-05-05 Fused salt electrolysis cell

Publications (1)

Publication Number Publication Date
US3118827A true US3118827A (en) 1964-01-21

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US108039A Expired - Lifetime US3118827A (en) 1961-05-05 1961-05-05 Fused salt electrolysis cell

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US (1) US3118827A (enrdf_load_stackoverflow)
AT (1) AT241835B (enrdf_load_stackoverflow)
BE (1) BE617283A (enrdf_load_stackoverflow)
CH (1) CH417123A (enrdf_load_stackoverflow)
DE (1) DE1184966B (enrdf_load_stackoverflow)
DK (1) DK104863C (enrdf_load_stackoverflow)
FR (1) FR1322529A (enrdf_load_stackoverflow)
GB (1) GB959636A (enrdf_load_stackoverflow)
NL (2) NL136135C (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4108743A (en) * 1977-05-02 1978-08-22 Ford Motor Company Method and apparatus for separating a metal from a salt thereof
FR2554462A1 (fr) * 1983-11-08 1985-05-10 Degussa Dispositif et procede pour l'electrolyse ignee d'halogenures de metaux alcalins

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1478502A (en) * 1974-11-25 1977-07-06 Falconbridge Nickel Mines Ltd Electrowinning metal from chloride solution
US9357881B2 (en) 2012-03-31 2016-06-07 Pitco Frialator, Inc. Oil level detection system for deep fat fryer

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB516775A (en) * 1937-07-06 1940-01-11 Du Pont Improvements in or relating to fused salt electrolysis cells
US2924558A (en) * 1958-06-25 1960-02-09 Du Pont Fused salt electrolysis

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB516775A (en) * 1937-07-06 1940-01-11 Du Pont Improvements in or relating to fused salt electrolysis cells
US2924558A (en) * 1958-06-25 1960-02-09 Du Pont Fused salt electrolysis

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4108743A (en) * 1977-05-02 1978-08-22 Ford Motor Company Method and apparatus for separating a metal from a salt thereof
FR2554462A1 (fr) * 1983-11-08 1985-05-10 Degussa Dispositif et procede pour l'electrolyse ignee d'halogenures de metaux alcalins
US4584068A (en) * 1983-11-08 1986-04-22 Degussa Aktiengesellschaft Device and process for the fused-salt electrolysis of alkali metal halides

Also Published As

Publication number Publication date
NL136135C (enrdf_load_stackoverflow)
DK104863C (da) 1966-07-11
BE617283A (fr) 1962-11-05
GB959636A (en) 1964-06-03
DE1184966B (de) 1965-01-07
CH417123A (de) 1966-07-15
NL278057A (enrdf_load_stackoverflow)
AT241835B (de) 1965-08-10
FR1322529A (fr) 1963-03-29

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