US3496089A - Electrode construction - Google Patents

Electrode construction Download PDF

Info

Publication number
US3496089A
US3496089A US573099A US3496089DA US3496089A US 3496089 A US3496089 A US 3496089A US 573099 A US573099 A US 573099A US 3496089D A US3496089D A US 3496089DA US 3496089 A US3496089 A US 3496089A
Authority
US
United States
Prior art keywords
anode
cell
electrode construction
transverse
members
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
US573099A
Other languages
English (en)
Inventor
Fin Enok Folkestad
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.)
NORSK HYDRO ELEKTRISK KVAELSLO
NORSK HYDRO ELEKTRISK KVAELSLOF AB
Original Assignee
NORSK HYDRO ELEKTRISK KVAELSLO
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
Application filed by NORSK HYDRO ELEKTRISK KVAELSLO filed Critical NORSK HYDRO ELEKTRISK KVAELSLO
Application granted granted Critical
Publication of US3496089A publication Critical patent/US3496089A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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
    • C25C7/02—Electrodes; Connections thereof
    • C25C7/025—Electrodes; Connections thereof used in cells for the electrolysis of melts

Definitions

  • An electrode construction for the electrolysis of salt fusions in an electrolytic cell employing electrodes having substantially vertical working surfaces with a cathode on each side of an anode having openings in the lower part.
  • Cathodic members extend from one cothode to the other and run through the openings in the intermediate anode.
  • the cathodic members are vertically arranged plates and the openings are downwardly open, vertically elongated slits.
  • the anode is composed of alternate longer anode rods and shorter anode rods located side by side and the lower part of the shorter anode rods are shaped to guide the flow of the melt outwardly from the mid-plane of the anode.
  • the lower part of the shorter anode rods is cut symmetrically to form an edge.
  • This invention relates to an electrode construction for the electrolysis of fused salts in an electrolytic cell employing electrodes having substantially vertical working surfaces, and more particularly for the production of magnesium and chlorine from a MgCP-containing fusion.
  • the prior art comprises a number of types of electrolytic cells for the electrolysis of molten chlorides, in particular chlorides of metals of groups 1 and 2 of the periodic system of the elements.
  • molten chlorides in particular chlorides of metals of groups 1 and 2 of the periodic system of the elements.
  • the electrolyte used in such cells usually consists of alkali metal chlorides and alkali earth metal chlorides, and possibly minor amounts of fluorides.
  • the cathodes are usually made of iron or steel and the anodes of graphite.
  • Another object of the invention is to provide an electrode construction which permits a high production capacity of a cell of a given size.
  • Still another object of the invention is to provide an electrode construction which permits simplification and rationalization in operating the electrolytic cell.
  • a further object of the invention is to provide an electrode construction resulting in a relatively low overall cell resistance and thus in a low cell voltage at a given amperage, and permitting a relatively high amperage to be used at a given voltage.
  • the invention thus relates to an electrode construction for the electrolysis of fused salts in an electrolytic cell employing electrodes having substantially vertical working surfaces, more particularly for the production of magnesium and chlorine from a Mgcl -containing fusion, and the electrode construction according to the invention is characterized by transverse cathode members arranged in the electrolysis zone between the electrodes, which cathode members extend into the anode zone.
  • the electrode construction consists of an anode, a cathode on each side of the anode, and transverse cathode members connecting the two cathodes and running through recesses in the intermediate anode.
  • Each of the transverse cathode members is preferably welded to the cathodes.
  • transverse as used herein to describe the cathode members of the invention means transverse relative to the substantially vertical electrodes. It will be understood, however, that this term is not limited to mean perpendicularly or normally arranged relative to the substantially vertical electrodes, as such mode of arrangement is not a necessary requirement for the usefulness of the transverse cathode members.
  • the essential requirement is that the transverse cathode members extend sufficiently far in horizontal direction to extend into the anode zone, i.e. so that part of the transverse cathode member will be within the general contour of the anode, and preferably so that the transverse cathode members extend all the way through the anode as described above.
  • transverse cathode members can have any suitable shape and cross section.
  • they are plates or rods, if desired with a somewhat streamlined cross section. I prefer, however, to use as transverse cathode members substantially vertically mounted plates.
  • the transverse cathode members are preferably arranged parallel with each other, evenly spaced from each other and at right angles with the general side plane of the anode.
  • a more irregular mode of arrangement may be desirable when particular considerations so dictate, for instance to make room for other appurtenances of the cell, or to provide accessibility for means for removal of settlings from the cell, etc.
  • the transverse cathode members suitably can be star-shaped, the centre of the star being on the axis of the anode, so as to divide the lower part of the anode into a number of segments, preferably 3-6 segments
  • the transverse cathode members can be parallel plates.
  • the distance between the transverse cathode members when the anodes are substantially plate-shaped, such as is the case in cells of the electrolytic type, can vary within a broad range, but more suitably is 10-40 cm., and preferably from 15 to 20 cm.
  • the abovementioned recesses in the anode for passing the transverse cathode members therethrough are substan tially vertical slits in the lower part of the anode.
  • the cross section of the anode has the shape of an oblong rectangle the lower part of the anode will thus have a fork-like shape.
  • the number of fork prongs i.a. will depend on the horizontal length of the anode.
  • the number of fork prongs is suitably from 3 to 15, preferably from 6 to 10.
  • An anode of this shape is advantageously constructed by using alternately long and short graphite rods which are placed side by side and held together in conventional manner by suitable clamping means and bolts.
  • the lower end of the short graphite rods are so shaped that the flow of the melt which near an anode is directed upward due to the electrolytic gas evolution on the anode surface, is deflected outward from the midplane of the anode, i.e. away from the anode, and so as to facilitate the upward flow of the melt and avoid turbulence.
  • FIG. 1 is a plan view of an electrode construction according to the invention
  • FIG. 2 is a vertical section along the line A-A of FIG. 1
  • FIG. 3 is a side view of the construction shown in FIG. 1 (although curtains 7 have been omitted in FIGS. 1 and 2 for the sake of clarity).
  • Identical parts shown in the drawing have identical reference numerals in all the figures, which show cathode shaft 1, auxiliary or front cathodes 2, transverse cathode members 3, long anode rods 4, short anode rods 5 with the lower part 6 thereof, and in FIG. 3 also curtains or partitions 7 have been indicated be tween the anode and the cathodes.
  • the lower end 6 of the short anode rods 5 have been shown (see FIG. 3) cut symmetrically to form an edge. If this edge is made very sharp it will soon be consumed during electrolysis. I prefer, therefore, to make this edge less sharp, i.e. blunt or rounded. If desired, the entire lower end 6 of the short anode rods 5 can be rounded, for instance so as to give the end 6 a more or less streamline shape. The preferred shape will i.a. depend on the construction of cell and the size thereof.
  • the electrode construction illustrated in FIGURES l-3 is suitable for use in an electrolytic cell.
  • the anodes are placed transversally of the cell, each anode having, suitably spaced therefrom, a cathode at each side.
  • a gas-collectin cover or hood usually made of a ceramic material and forming said curtains or partitions 7, under which cover the gas evolving from the anode accumulates to be withdrawn through suitable means.
  • the conventional cell usually has 3-5 anodes and twice as many cathodes, a curtain or partition being provided everywhere between an anode and a cathode.
  • the cell will be divided into a number of anode chambers and cathode chambers, the metal produced on the cathodes accumulating in the cathode chambers on top of the melt.
  • Dividing a cell into a relatively high number of such chambers results in a relatively large portion of the surface area of the bath being taken up by the many partitions between anode and cathode chambers.
  • the partitions would normally take up more than 20 percent of the surface area of the bath.
  • Such a cell has 5 cathode chambers from which produced metal is to be withdrawn at intervals, and the high number of metal withdrawal operations required per ton of metal produced is a drawback.
  • the electrode construction of the invention permits the useful surface area of the electrodes to be considerably increased over that of the conventional electrode construction. This is partly due to the fact that when using the electrode construction of the invention, one can advantageously increase the thickness of each anode and reduce the number of anodes per cell of a given size, which means fewer curtains per cell than what has been found suitable using the conventional electrode construction. In the case of a cell in which one would conventionally use 3 to 5 anodes and 6 to 10 cathodes, one can advantageously use one, two or three of the electrode assemblies shown in the drawing. The latter arrangement permits a considerable increase in the amperage of the cell.
  • the electrode construction of the invention also provides other advantages.
  • the assembly and operation of the cell can be simplified. More particularly, the withdrawal of metal from the cell can be rationalized.
  • the application of the electrode construction of the invention is not limited to electrolytic cells of a special cell type. Further, it is not necessarily required that the partitions of the cell be situated between anode and cathode as shown in FIG. 3 (curtains 7). Such partitions primarily serve the purpose of isolating from the atmosphere the gas evolved on the anodes and the partitions can well be placed in the peripheral parts of the cell outside of the electrode construction of the invention.
  • an anode is constructed, according to an embodiment of the invention, from alternate long short anode rods. Comparing the surface area of such an anode with that of a similar anode wholly constructed from long rods, it will be understood that the first-. entioned anode (having a fork-like shape as shown in FIG. 2) will have the larger surface area if the thickness of the anode is greater than the width of the rod. I prefer, therefore, when constructing the anode in this way, to make the anode thickness greater than the width of the rod.
  • the invention is not limited to electrode constructions in which the thickness of the anode is greater than the width of the rods from which the anode is made.
  • recesses of the shape and size desired can of course be provided in any suitable way, for instance, by cutting out recesses from an integrally made anode, or from any conventionally made anode.
  • the advantages of the electrode construction of the invention can be obtained in some measure, partly because the area of the lower part of the anode can then be utilized more efiiciently in the electrolytic process.
  • the recesses, as well as the transverse cathode members, can extend upward as far as is desired, although not above the bath level, and, if desired, the upper contour of the transverse members can be suitably adapted in shape to the lower end of the curtains 7 and to the lower end of the short rods 5, etc.
  • EXAMPLE 1 In an electrolytic cell having four sets of electrodes, each set comprising one anode, two cathodes and 3 transverse cathode members, the arrangement being essentially as shown in FIG. 3, a fused salt mixture was electrolyzed consisting substantially of MgCl (about by weight), CaCl (about 35%), NaCl (about 30%) and KCl (about The transverse cathode members were vertically arranged steel plates, 30 cm. in height and 1 cm. thick, the ends of which were welded to the respective cathodes. The distance between the successive transverse members was 40 cm.
  • the temperature of the bath during electrolysis was 760 C., and the current strength was 38,000 amperes.
  • the results of the operations were (average) Energy consumption kwh./kg. mg 17.6
  • the electrode construction of the invention can be mounted in alternative ways, for instance so as to supply the current to the transverse members through cathodic conductor bars or plates provided in the walls of the cell; or the walls of the cell can be made of steel, in which case the transverse members can be arranged to extend between opposite cell walls, either longitudinally or transversely of the cell.
  • the conductor bars, plates or walls would have cathodic function, to a smaller a larger extent; however, this cathodic function would be transferred to the transverse electrode members to an increasing degree as the number and size of such transverse members are increased, and the relative importance of the conventional cathodes qua cathodes is then correspondingly reduced.
  • the conventional cathodes are reduced to current supply means, which could be arranged passing through the wall or the bottom of the cell, or in any other suitable way obvious to those skilled in the art.
  • Electrode construction for the electrolysis of salt fusions in an electrolytic cell employing electrodes having substantially vertical working surfaces, comprising a cathode on each side of an anode having openings in the lower part thereof, and cathodic members extending from one cathode to the other and running through said openings in the intermediate anode.
  • Electrode construction as set forth in claim 3 wherein said anode is composed of alternate longer anode rods and shorter anode rods located side by side.

Landscapes

  • 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)
US573099A 1965-09-01 1966-08-17 Electrode construction Expired - Lifetime US3496089A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NO15956365 1965-09-01

Publications (1)

Publication Number Publication Date
US3496089A true US3496089A (en) 1970-02-17

Family

ID=19909288

Family Applications (1)

Application Number Title Priority Date Filing Date
US573099A Expired - Lifetime US3496089A (en) 1965-09-01 1966-08-17 Electrode construction

Country Status (6)

Country Link
US (1) US3496089A (enEXAMPLES)
DE (2) DE6607971U (enEXAMPLES)
FI (1) FI44585B (enEXAMPLES)
GB (1) GB1162551A (enEXAMPLES)
IL (1) IL26377A (enEXAMPLES)
SE (1) SE313548B (enEXAMPLES)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1296046A (en) * 1917-03-08 1919-03-04 Georges Charbonneaux Electrolytic cell.
CA573870A (en) * 1959-04-14 Egami Ichiro Production of magnesium by fused salt electrolysis
US2987463A (en) * 1958-06-06 1961-06-06 Diamond Alkali Co High amperage diaphragm cell for the electrolysis of brine

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA573870A (en) * 1959-04-14 Egami Ichiro Production of magnesium by fused salt electrolysis
US1296046A (en) * 1917-03-08 1919-03-04 Georges Charbonneaux Electrolytic cell.
US2987463A (en) * 1958-06-06 1961-06-06 Diamond Alkali Co High amperage diaphragm cell for the electrolysis of brine

Also Published As

Publication number Publication date
SE313548B (enEXAMPLES) 1969-08-18
IL26377A (en) 1970-07-19
FI44585B (enEXAMPLES) 1971-08-31
GB1162551A (en) 1969-08-27
DE1671462B1 (de) 1970-08-27
DE6607971U (de) 1971-05-27

Similar Documents

Publication Publication Date Title
SU1056912A3 (ru) Катод алюминиевого электролизера
US3598715A (en) Electrolytic cell
EP0150285B1 (en) Process for the electrolytic production of fluorine and novel cell therefor
US3930981A (en) Bipolar electrolysis cells with perforate metal anodes and baffles to deflect anodic gases away from the interelectrodic gap
US4707239A (en) Electrode assembly for molten metal production from molten electrolytes
CA1280715C (en) Electrolytic cell with anode having projections and surrounded by partition
US3067124A (en) Furnace for fused-bath electrolysis, particularly for aluminum production from alo
SU1364243A3 (ru) Электролизер с горизонтальным ртутным катодом
US3496089A (en) Electrode construction
CN103540958A (zh) 设置有吊挂隔墙的铝电解槽
US3515661A (en) Electrolytic cells having detachable anodes secured to current distributors
US3907651A (en) Method for the molten salt electrolytic production of metals from metal chlorides and electrolyzer for carrying out the method
CN201883156U (zh) 一种铝电解槽的阳极结构
KR880000708B1 (ko) 환원전해조
US2749301A (en) Mercury type, caustic, chlorine cell
US1092369A (en) Process of making chlorates and apparatus therefor.
USRE28829E (en) Fused salt electrolyzer for magnesium production
US4008143A (en) Electrode assembly for an electrolytic cell
US4196067A (en) Absorption of magnetic field lines in electrolytic reduction cells
SU1036808A1 (ru) Диафрагменный электролизер
US1921376A (en) Apparatus for electrolysis of fused bath
KR880000709B1 (ko) 염화마그네슘용 전해조
US1186898A (en) Electrolytic apparatus.
CN108396333A (zh) 一种降低水平电流改善电流分布的铝电解槽阴极结构
SU514045A1 (ru) Электролизер дл получени магни и хлора