EP0220557A1 - Electrode composée inerte, en particulier anode pour l'électrolyse en bain fondu - Google Patents

Electrode composée inerte, en particulier anode pour l'électrolyse en bain fondu Download PDF

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Publication number
EP0220557A1
EP0220557A1 EP86113930A EP86113930A EP0220557A1 EP 0220557 A1 EP0220557 A1 EP 0220557A1 EP 86113930 A EP86113930 A EP 86113930A EP 86113930 A EP86113930 A EP 86113930A EP 0220557 A1 EP0220557 A1 EP 0220557A1
Authority
EP
European Patent Office
Prior art keywords
active elements
composite electrode
elements
plate
electrode according
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.)
Granted
Application number
EP86113930A
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German (de)
English (en)
Other versions
EP0220557B1 (fr
Inventor
Christine Dr. Zöllner
Herbert Hahn
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.)
C Conradty Nuernberg GmbH and Co KG
Original Assignee
C Conradty Nuernberg GmbH and Co KG
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 C Conradty Nuernberg GmbH and Co KG filed Critical C Conradty Nuernberg GmbH and Co KG
Priority to AT86113930T priority Critical patent/ATE43366T1/de
Publication of EP0220557A1 publication Critical patent/EP0220557A1/fr
Application granted granted Critical
Publication of EP0220557B1 publication Critical patent/EP0220557B1/fr
Expired 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
    • C25C3/06—Electrolytic production, recovery or refining of metals by electrolysis of melts of aluminium
    • C25C3/08—Cell construction, e.g. bottoms, walls, cathodes
    • C25C3/12—Anodes
    • 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

  • the invention relates to an inert composite electrode, in particular anode for melt flow electrolysis, for example for the extraction of aluminum, magnesium, sodium, lithium, among other things consisting of an active part in the form of a plurality of rod-shaped active elements, in particular made of oxide ceramics, with their longitudinal axes parallel to each other and are arranged in mutually aligned groups, an electrode holder which comprises a current-conducting plate, with one main surface of which the electrode elements are in frictional contact with their end faces, and a connecting arrangement which connects the active elements in groups to one another and keeps them in contact with the plate.
  • melt flow electrolysis e.g. In aluminum production, intensive development is underway to use so-called inert anodes, which consist in particular of oxide ceramics, for the electrolysis instead of the consumable carbon anodes.
  • the inert electrodes must, on the one hand, take into account the requirements of the existing cells that are still equipped with carbon anodes. This applies in particular with regard to the power supply line and the arrangement and / or the dimensioning of the active parts of the anodes. On the other hand, of course, the requirements made of the material from which the active parts of the inert anodes are made must also be taken into account. This applies in particular with regard to the physical parameters and the manufacturing technology.
  • An inert composite electrode of the type defined in the introduction is known from DE-PS 30 03 922. This essentially consists of an active part, an electrode holder and an arrangement for connecting the two first-mentioned assemblies.
  • the active part is formed by a plurality of rod-shaped active elements. These are arranged with their longitudinal axes parallel to one another and in groups aligned with one another. The total cross section perpendicular to the longitudinal axes of the active elements corresponds approximately to the corresponding cross section of a conventional carbon anode for a melt flow electrolysis cell.
  • the individual active elements consist of an oxide ceramic material.
  • a tubular support is provided to hold the active elements and to supply current to them.
  • a further tube is arranged concentrically in the latter, the lower end of which is provided with a base plate.
  • This base plate has a central bore through which a rod-shaped current feeder is passed, the lower end of which, below the base plate, is provided with a current-conducting pressure plate. With this pressure plate, the upper end faces of the active elements are brought into mechanical and electrical contact in a non-positive manner.
  • the active elements aligned in groups with one another each have a bore in their upper section, which are also aligned with one another with respect to a group.
  • a suspension rod the ends of which rest on a support plate, is passed through the mutually aligned bores of a group.
  • This support plate and the base plate mentioned are to be clamped using screw bolts, as a result of which the upper end faces of the active elements are brought into contact with the current-carrying pressure plate. If appropriate, an electrically highly conductive intermediate layer can be introduced between the end faces of the active elements and the pressure plate.
  • This known electrode construction has several serious disadvantages.
  • the production of the bores in the head sections of the active elements requires a greater production outlay. They can only be generated when the oxide ceramic active elements are green.
  • bores, in particular with regard to the alignment of the active elements arranged in groups are subject to greater tolerances, since such tolerances already occur in the green state during the production of the active elements and further dimensional deviations are unavoidable when the active elements are sintered.
  • the bores of a group of active elements are not exactly aligned, so that some of the active elements which are arranged one below the other on a suspension rod do not come into contact with their end faces, or do not come into sufficient contact with the current-carrying plate of the electrode holder.
  • the aforementioned weakening of the cross section of the active elements of the known anode also reduces the mechanical strength of the active elements, specifically in an area in which on the one hand the respective suspension rod exerts an increased compressive stress on the material of the active elements due to its prestressing and on the other hand also the highest tensile stresses due to the Weight of the active elements occur. Because of this, the greatest mechanical stresses act precisely in the area of the weakened cross section of the active elements, so that there is an increased risk of the electrode elements breaking at the point mentioned.
  • the active elements each have a plate side Have head section, which is substantially wedge-shaped in its cross section perpendicular to the line of flight of a group and in the direction of the plate-side end face, and with each of the two opposite wedge faces of the head section of the respective active element, a tensioning element is brought into contact with a wedge face, the wedge angle of which corresponds essentially to the respective wedge surface of the head section, so that there is a dovetail connection.
  • the active part of the anode according to the invention is thus broken down into a plurality of rod-shaped active elements, as is known per se.
  • the active elements have a favorable design in terms of production technology, because the wedge-shaped head section complies with the design in ceramic technology, whereas the holes provided in the head section of the active elements of the known anode already cause a number of problems in terms of production technology, as has been explained above.
  • the active elements in the area of the wedge bracing are only subjected to pressure, which can be easily accommodated by the oxide-ceramic material due to its high compressive strength, especially since the cross section in the pressurized area of the active elements is enlarged due to the wedge shape of the head sections.
  • the tensile stresses due to the weight of the active elements can also be absorbed. Overall, this results in a mechanically very stable anode construction.
  • the wedge or dovetail bracing of the active elements by means of the clamping elements described also results in a self-adjusting effect, with the result that all of the active elements come with their end faces in intimate contact with the current-carrying plate, with bridging or due to compensation for any existing manufacturing tolerances. Due to the self-adjusting wedge tension between the active elements on the one hand and the tensioning elements or the plate on the other hand, any movements of the assemblies towards one another are compensated for due to the different thermal expansion coefficients of the materials, so that the end faces of the active elements also have intimate contact with the tensioning elements during operation of the anode and the current-carrying plate is preserved. In this way, a permanent and both electrically and mechanically optimal connection between the metallic power supply and the ceramic active elements is guaranteed.
  • the current transfer area between the current-carrying plate and the active elements is increased in the anode according to the invention in that the tensioning elements are also in electrical connection both to the plate and to the wedge surfaces of the electrode elements, so that the latter Increase the total contact area of the active elements in relation to the component to be energized accordingly. Due to the increased total contact area, the voltage drop is also reduced accordingly.
  • the current flow at this critical point is significantly improved.
  • the area utilization of the anode according to the invention is therefore very good, since the streamlines have a certain lateral wrap and the effective anode area is approximately equal to the projected anode area.
  • the anode elements consist of a material with thermistor properties
  • they are in the cold, i.e. non-conductive area of the anode elements measures taken to increase the conductivity, namely the cross-sectional enlargement in the head section of the anode elements, the special design of the material of the anode elements to increase the conductivity and the enlarged current transmission area crucial for increasing the electrical efficiency.
  • the anode arrangement according to the invention therefore has a very good electrochemical efficiency.
  • Channels between the active elements are formed between the active elements arranged in groups, at least where the tensioning elements are provided.
  • Active elements circulate the melt and the electrolyte in these channels, which effectively counteracts an otherwise possible depletion of the electrolyte.
  • these channels provide enough space for the gas discharge so that the developed gas is quickly removed. Both contribute to an increase in the electrochemical efficiency of the process carried out with the electrodes according to the invention.
  • the active elements of a group can be in line with each other in their escape line.
  • only channels are formed between the active elements where there are clamping elements between the active elements.
  • the wedge-shaped widening of the head sections of the active elements has already largely reduced the voltage drop in the cold region. Nevertheless, it may still be advisable to design the electrical conductivity of the material of the active elements higher in the area of the head section than in the rest of the area after these materials have thermistors possess properties. This is possible, for example, in that the material of the active elements in the area of the head section is a cermet, which is preferably tin oxide containing silver. The current conductivity in the critical head section of the active elements in the electrode according to the invention is thus further improved.
  • a contact layer in order to reduce the contact resistance between the current-carrying plate and the active elements even further, it can be advantageous for a contact layer to be introduced between the relevant main surface of the plate and the corresponding end faces of the active elements.
  • This can be formed by a network of highly conductive metal, in particular copper.
  • a continuous clamping element or separate clamping elements can be provided on both sides for each aligned group of active elements.
  • the tensioning element is designed for fastening two opposite active elements of two adjacent groups and for this purpose has two opposite wedge surfaces with an essentially mirror-image arrangement. This further reduces the effort in manufacturing and assembly
  • the mentioned clamping element can expediently be trapezoidal in cross section perpendicular to the line of alignment of the groups of active elements.
  • clamping elements are assigned to each active element and the length of a clamping element essentially corresponds to the length of an active element.
  • the plate is expediently cooled by water cooling, for which the plate is designed as a hollow body, within which channels for the cooling water are arranged.
  • the respective current feeder to the plate is guided through the interior of the hollow body and is electrically connected to the inside of the main surface with which the active elements are in contact.
  • the inert electrode according to the invention in particular anode for the melt flow electrolysis, essentially consists of three assemblies, namely an active part, generally designated 10, an electrode holder, generally designated 30, and an arrangement, generally designated 40, for connecting the two first-mentioned assemblies.
  • the active part consists of a plurality of rod-shaped active elements, which are generally designated 20. These are arranged with their longitudinal axes vertically aligned in the cell in the assembly position parallel to one another and in groups 11, 12, 13 etc. aligned with one another along the alignment line 25 (FIG. 3). They are essentially square or rectangular in their cross section perpendicular to their longitudinal axis. They consist of an electrically conductive and electrochemically active oxide ceramic material that can be described in more detail.
  • the active elements 20 each have a head section 21, which is widened by wedge surfaces 23 in its cross section lying perpendicular to the alignment line of a group and in the direction of the corresponding end face 22.
  • the essentially plate-shaped electrode holder 30 has a main surface 31, as seen in the electrolysis cell in the assembly position, on which the active elements 20 are mechanically and electrically kept in contact with their end surfaces 22. This is done with the aid of the connecting arrangement 40 representing tensioning elements 41. These tensioning elements are so trapezoidal in their cross section parallel to the longitudinal axis of the active elements 20 and perpendicular to the alignment line of a group that the two opposite wedge surfaces 42 with the wedge surfaces 23 lying at the same angle are two in two neighboring groups, e.g. 12, 13, opposite active elements 20 with appropriate bias are in contact.
  • the clamping elements 41 are screwed to the plate-shaped electrode holder 30 by means of screws.
  • two adjacent groups 11, 12, 13, etc. of active elements are spaced apart such that channels 50 are formed which, in the manner described, circulate the electrolyte or the melt between the lower ones, into the melt or into the electrolyte immersed sections 26 of the active elements 20 is made possible and, on the other hand, ensure rapid removal of the gas developed in the electrolysis process between the groups of active elements 20 arranged upwards.
  • the plate-shaped electrode holder 30 is designed as a hollow body, consisting of a lower horizontal plate 32, an upper plate 33 arranged parallel to the first and side walls 34 perpendicular thereto.
  • the cavity serves for the circulation of cooling water in the interior 35 of the electrode holder 30.
  • This is a cooling water Inlet pipe 36 is provided which opens into the interior 35 on the edge.
  • the cooling water circulates along spiral-shaped guide walls 37 through the interior 35 of the plate-shaped electrode holder 30 up to its central area and from there again into the peripheral area, from where the correspondingly heated cooling water is drawn off through a cooling water drain pipe 38.
  • the plate-shaped electrode holder 30 is further equipped with a plurality of current supply bolts 60, via which the electrical current is fed to the plate-shaped electrode holder 30 and is transmitted from there to the electrode elements 20.
  • a plurality of current supply bolts 60 via which the electrical current is fed to the plate-shaped electrode holder 30 and is transmitted from there to the electrode elements 20.
  • sleeves 61 are welded to the inner surface of the lower plate 33, which have an internal thread with which the lower and externally threaded section of the corresponding power supply bolt 60 is screwed.
  • protective sleeves 62 made of corrosion-resistant material.
  • a network 39 e.g. made of copper.
  • the plate-shaped electrode holder 30 and the clamping elements 41 and their clamping screws 43 are expediently made of steel. They can also consist of nickel or of steel or nickel alloys. Cover elements are provided to protect these components against corrosion.
  • the cover elements 44 arranged on the underside of the tensioning elements are secured to the tensioning elements 41, for example by means of a dovetail guide.
  • the side cover elements 45 can be screwed to the front ends of the clamping elements 41 by screws 46.
  • the active elements 20 expediently consist of doped oxide ceramic, e.g. Tin oxide, nickel ferrite or yttrium oxide.
  • the composition can be as follows: 94.1 atomic percent tin oxide 3.8 atomic% copper 2.1 atomic% antimony
  • the following dimensioning of the rod-shaped active elements has proven to be appropriate: Cross section of the upper face: 3 x 3 cm Cross section of the lower face: 2 x 2 cm Length: 25 cm Wedge angle: 20 ° Distance between two adjacent groups of electrode elements: 1.5 cm
  • the side length of the upper cross section can expediently be between approximately 2 and 6 cm.
  • the length of the active elements can be between approx. 15 cm and approx. 40 cm.
  • the aforementioned distance between two groups of active elements can be between approximately 1 cm and approximately 2 cm.
  • the wedge angle of the head section of the respective active elements can be between approximately 5 ° and approximately 25 °.
  • the described exemplary embodiment of the anode according to the invention was operated in an electrolysis test cell with the following operating data: Bath composition: cryolite 84% by weight A1F3 5% by weight A1203 10% by weight CaF2 1% by weight Temperature: 980-1000 C. Clamp voltage: 4-5 volts Current: 30 A. Current density at the anode: 2 A / cm2 Current density at the cathode: 0.14 A / cm2 Electrode distance: 3 cm Immersion depth of the anodes: 2cm

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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)
  • Resistance Heating (AREA)
  • Heterocyclic Carbon Compounds Containing A Hetero Ring Having Oxygen Or Sulfur (AREA)
  • Adhesives Or Adhesive Processes (AREA)
  • Electrodes For Compound Or Non-Metal Manufacture (AREA)
EP86113930A 1985-10-22 1986-10-08 Electrode composée inerte, en particulier anode pour l'électrolyse en bain fondu Expired EP0220557B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT86113930T ATE43366T1 (de) 1985-10-22 1986-10-08 Inerte verbundelektrode, insbesondere anode fuer die schmelzflusselektrolyse.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3537575 1985-10-22
DE19853537575 DE3537575A1 (de) 1985-10-22 1985-10-22 Inerte verbundelektrode, insbesondere anode fuer die schmelzflusselektrolyse

Publications (2)

Publication Number Publication Date
EP0220557A1 true EP0220557A1 (fr) 1987-05-06
EP0220557B1 EP0220557B1 (fr) 1989-05-24

Family

ID=6284182

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86113930A Expired EP0220557B1 (fr) 1985-10-22 1986-10-08 Electrode composée inerte, en particulier anode pour l'électrolyse en bain fondu

Country Status (10)

Country Link
US (1) US4840718A (fr)
EP (1) EP0220557B1 (fr)
AT (1) ATE43366T1 (fr)
BR (1) BR8604998A (fr)
CA (1) CA1299138C (fr)
DE (2) DE3537575A1 (fr)
ES (1) ES2003380A6 (fr)
HU (1) HU203133B (fr)
NO (1) NO168314C (fr)
ZA (1) ZA867953B (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2860247B1 (fr) 2003-09-30 2005-11-11 Pechiney Aluminium Dispositif et procede de raccordement d'anodes inertes destinees a la production d'aluminium par electrolyse ignee
WO2018092103A1 (fr) * 2016-11-19 2018-05-24 Jan Petrus Human Électrodes destinées à être utilisées dans l'électro-extraction des métaux

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH340346A (de) * 1956-01-23 1959-08-15 Aluminium Ind Ag Elektrode für die kathodische Stromzuführung bei nach dem Dreischichtenverfahren arbeitenden Aluminiumraffinationszellen
US3607713A (en) * 1969-05-07 1971-09-21 Quaker Oats Co Anode for production of aluminum metal
EP0022921A1 (fr) * 1979-07-20 1981-01-28 C. CONRADTY NÜRNBERG GmbH & Co. KG Electrode régénérable à stabilité de forme pour l'emploi à haute température
DE3003922A1 (de) * 1979-12-18 1981-06-25 Schweizerische Aluminium AG, 3965 Chippis Anode aus dimensionsstabilen oxidkeramischen einzelelementen

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3761385A (en) * 1971-06-30 1973-09-25 Hooker Chemical Corp Electrode structure
US3984304A (en) * 1974-11-11 1976-10-05 Ppg Industries, Inc. Electrode unit
US4357226A (en) * 1979-12-18 1982-11-02 Swiss Aluminium Ltd. Anode of dimensionally stable oxide-ceramic individual elements
DE3071075D1 (en) * 1980-10-27 1985-10-17 Conradty Nuernberg Electrode for igneous electrolysis
US4462088A (en) * 1981-11-03 1984-07-24 International Business Machines Corporation Array design using a four state cell for double density

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH340346A (de) * 1956-01-23 1959-08-15 Aluminium Ind Ag Elektrode für die kathodische Stromzuführung bei nach dem Dreischichtenverfahren arbeitenden Aluminiumraffinationszellen
US3607713A (en) * 1969-05-07 1971-09-21 Quaker Oats Co Anode for production of aluminum metal
EP0022921A1 (fr) * 1979-07-20 1981-01-28 C. CONRADTY NÜRNBERG GmbH & Co. KG Electrode régénérable à stabilité de forme pour l'emploi à haute température
DE3003922A1 (de) * 1979-12-18 1981-06-25 Schweizerische Aluminium AG, 3965 Chippis Anode aus dimensionsstabilen oxidkeramischen einzelelementen

Also Published As

Publication number Publication date
CA1299138C (fr) 1992-04-21
EP0220557B1 (fr) 1989-05-24
US4840718A (en) 1989-06-20
DE3663537D1 (en) 1989-06-29
NO864210D0 (no) 1986-10-21
NO168314C (no) 1992-02-05
BR8604998A (pt) 1987-07-14
HU203133B (en) 1991-05-28
NO864210L (no) 1987-04-23
NO168314B (no) 1991-10-28
HUT44087A (en) 1988-01-28
DE3537575C2 (fr) 1988-09-15
ES2003380A6 (es) 1988-11-01
ZA867953B (en) 1987-06-24
DE3537575A1 (de) 1987-04-23
ATE43366T1 (de) 1989-06-15

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