WO2000027168A1 - Electrode pour procedes electrometallurgiques - Google Patents

Electrode pour procedes electrometallurgiques Download PDF

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Publication number
WO2000027168A1
WO2000027168A1 PCT/EP1999/008443 EP9908443W WO0027168A1 WO 2000027168 A1 WO2000027168 A1 WO 2000027168A1 EP 9908443 W EP9908443 W EP 9908443W WO 0027168 A1 WO0027168 A1 WO 0027168A1
Authority
WO
WIPO (PCT)
Prior art keywords
component
graphite
electrode
core component
electrode according
Prior art date
Application number
PCT/EP1999/008443
Other languages
German (de)
English (en)
Inventor
Harald Lampey
Peter Glas
Thomas Zabel
Dieter Hans ZÖLLNER
Original Assignee
C. Conradty Nürnberg Gmbh
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 Nürnberg Gmbh filed Critical C. Conradty Nürnberg Gmbh
Priority to AU16511/00A priority Critical patent/AU1651100A/en
Publication of WO2000027168A1 publication Critical patent/WO2000027168A1/fr

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B7/00—Heating by electric discharge
    • H05B7/02—Details
    • H05B7/06—Electrodes
    • H05B7/08—Electrodes non-consumable
    • H05B7/085—Electrodes non-consumable mainly consisting of carbon
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B7/00—Heating by electric discharge
    • H05B7/02—Details
    • H05B7/14—Arrangements or methods for connecting successive electrode sections
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/25—Process efficiency

Definitions

  • the invention relates to an electrode for electrometallurgical processes with a jacket component made from a first graphite, a core component made from a second graphite and at least one connecting element for connection to a further electrode.
  • Electrodes which are made of a carbon material. These electrodes are also used in electrical reduction furnaces for electrical energy transfer to the reaction material.
  • Graphite has established itself as the carbon material for electrodes for electrometallurgical processes. Although graphite is used up in these processes, it has prevailed for electrometallurgical processes because advances in electrode technology and application have made it economically viable. There are several reasons why graphite electrodes are used up. One cause is the electrode erosion, which can be geometrically divided into the tip erosion and the side erosion. The ratio of the erosion values from peak erosion to side erosion is between 1: 1 and 1: 2. The peak erosion and the side erosion together make up about 85% of the total electrode consumption. The remaining 15% of the total electrode consumption is due to the falling off of electrode pieces and broken electrodes.
  • Graphite is a relatively expensive material. As a result, the consumption of graphite plays an essential role for an economical driving arc furnace and accounts for approximately 4% to 8% of the total operating costs of an arc furnace. There have therefore already been various measures for reducing the electrode consumption, which are primarily intended to reduce side burn-off by oxidation. This involves, in particular, a coating of the electrodes on their outer circumferential surface and water cooling of the electrodes.
  • EP 0 142476 A discloses an electrode of the generic type, which consists of a jacket component made of a first graphite and a core component made of a second carbon material, which has different mechanical, thermal and electrical properties compared to the first Graphite has to reduce the internal mechanical stress in the electrode.
  • the graphite of the cladding component is said to have a higher electrical and thermal conductivity than the carbon material of the core.
  • the jacket component should consist of electrographite and the core component of anthracite material.
  • the object of the invention is to design an electrode of the generic type in such a way that it has a low consumption of graphite and allows an increased power supply of electrical energy in an arc furnace.
  • the second graphite of the core component has a lower specific electrical resistance and a higher bulk density than the first carbon material of the cladding component.
  • the tip erosion of the electrode is particularly uniform on the one hand and particularly low on the other hand.
  • An electrode string constructed from electrodes according to the invention can absorb particularly high twists and bending forces. It is therefore particularly elastic and therefore not very susceptible to electrode breakage after a scrap collapse.
  • the invention makes it possible to circumvent the restrictions which are imposed by the manufacturing process for graphite electrodes and which make the manufacture of large-format electrodes with low specific electrical resistance difficult. Problems due to eddy current losses and interference from neighboring electrodes (proximity effect), which occur with large Trode cross-sections occur are reduced.
  • the weight of the graphite electrode component divided by the volume is defined as the bulk density. Pores are also included in the bulk density.
  • the electrodes according to the invention enable a higher furnace output without the use of additive energies and without increased effort for the construction of the support arms and the electrode control.
  • the energy loss at the electrodes is reduced.
  • the total current is divided into several parallel currents in the electrode. As a result, the total current is transported with lower voltage losses since the core component has a lower resistivity than the sheath component.
  • the tuning is chosen so that the specific electrical resistance of the cladding component is 20% to 25% higher than that of the core component.
  • the bulk densities are matched to one another in such a way that the core component has a bulk density that is 9% to 10% higher than the shell component.
  • Show it 1 shows a longitudinal section through an electrode string composed of several electrodes according to the invention in a first embodiment of an electrode according to the invention
  • FIG. 2 shows a cross section through the electrode according to section line II-II in FIG. 1 on an enlarged scale compared to FIG. 1,
  • Fig. 3 shows a longitudinal section through a composed of electrodes according to a second embodiment of the invention
  • Fig. 4 shows a cross section through the electrode according to the section line
  • Fig. 5 shows a longitudinal section through a third embodiment of a
  • FIG. 6 shows a cross section through a fourth embodiment of an electrode according to the invention.
  • each electrode 1 shows an electrode string which is formed from several electrodes 1 which are identical to one another.
  • Each electrode 1 has a jacket component 2 and a core component 3.
  • the jacket component 2 is designed as a hollow cylinder with a circular cross-section, in which the solid circular cylindrical core component 3 is arranged, leaving an annular gap 4 free.
  • the jacket component 2 and the core component 3 and thus also the annular gap 4 are concentric a common central longitudinal axis 5 arranged.
  • the annular gap 4 can be filled with a coating component 6 attached to the core component 3.
  • the core component 3 has a radius R k .
  • the jacket component 2 has an inner radius R; and an outer radius R a .
  • the ratio of the radii to one another is 0.3 ⁇ Rk / (R a + Ri) ⁇ 3.0 and preferably 0.3 ⁇ R (R a + Ri) ⁇ 0.8.
  • the relationship R a Ri defines the wall thickness of the casing component 2.
  • the electrodes 1 each have a so-called box 7 at their ends, which is a frustoconical recess 7 which is formed only at both ends of the casing component 2 and tapers towards the core component 3, on the inside of which a correspondingly tapering internal thread 8 is formed.
  • So-called nipples 9 are used to connect two electrodes 1, which are double-conical, ie double-truncated cone-shaped bodies with two corresponding conical external threads 10. Because of the frustoconical configuration of the nipple 9 and the box 7, the respective nipple 9 can be inserted relatively deep into a box 7 before the external thread 10 of the nipple 9 overlaps the internal thread 8.
  • the threaded connection can then be produced with a few turns, in such a way that the adjacent annular end faces 11, 12 of two adjacent jacket components 2 come into contact with one another.
  • Another tight, two-dimensional connection exists via the external thread 10 and internal thread 8.
  • the end faces 13 of the nipple 9 and the facing end faces 14 of the adjacent core components 3 have a small distance from one another.
  • the jacket component 2 consists of a first graphite, which is solid and compact. This is preferably an electrographite with a specific electrical resistance of 6.5 to 9.0 ⁇ m and a bulk density of 1.5 to 1.64 g / cm 3 .
  • the core component 3 consists of a compact second graphite.
  • the second graphite is an electrographite with a specific electrical resistance of 4.5 to 6.4 ⁇ m and a bulk density of 1.65 to 1.75 g / cm 3 .
  • This second graphite for the core component 3 is the same graphite as is used for the nipple 9. Due to selected raw materials, small grain size and multiple impregnations, it has a high bulk density and a low specific electrical resistance.
  • the relatively high bulk density is achieved by multiple impregnation with liquid pitch and annealing at 800 ° C to 900 ° C.
  • the core component 3 can contain an application, ie a thin layer of metal or metal alloy (not shown in the drawing), as a result of which the overall electrical resistance of the core component 3 can be suppressed below the limit values that are possible for graphite.
  • the metals that can be used are aluminum, titanium and nickel.
  • Aluminum is preferably used as the material for the coating component 6, which fills the annular gap between the core component 3 and the jacket component 2. Since aluminum is an electrical conductor, this improves the transport of electricity inside large-sized electrodes because it counteracts the current displacement on the outside of the electrode. Aluminum also acts on the during operation the temperatures occurring as a thermoplastic coating, which compensates for different thermal expansions of core component 3 and jacket component 2.
  • the coating component 6 can, however, also be constructed from several layers of metallic aluminum, nickel, aluminum alloys and one or more layers of refractory oxides, such as Si0 2 or A1 2 C » 3 .
  • the annular gap can also be filled with a coating component 6 made of a carbonized mass.
  • the jacket component 2 and the core component 3 are non-positively connected to one another by this carbonized impregnation.
  • the coating component 6 can furthermore also be formed by thermoplastic material, for example a so-called green mass, ie a mixture of pitch and tar, which softens during operation, that is to say at higher temperatures, and flows in pores and interspaces and thus adhesion caused between the core component 3 and the sheath component 2.
  • thermoplastic material for example a so-called green mass, ie a mixture of pitch and tar, which softens during operation, that is to say at higher temperatures, and flows in pores and interspaces and thus adhesion caused between the core component 3 and the sheath component 2.
  • a thermoplastic coating component 6 also compensates for the stresses that can occur because the second graphite of the core component 3 has a higher coefficient of thermal expansion than the first carbon material of the jacket component 2.
  • the electrodes 1 'shown in FIG. 3, assembled to form an electrode string, have jacket components 2' with core components 3 '.
  • the core component 3 'each has at its lower end a frustoconically widening section which bears in a corresponding area of the box 7' against the jacket component 2 '.
  • the core component 3 ' is held in the direction of the axis 5 against slipping out of the casing component 2' in one direction - upwards in FIG. 3.
  • the core component 3 ' is secured by the nipple 9.
  • the jacket component 2 ' is provided on its outside with a known annular coating 16, which serves to reduce the side burn-up.
  • a so-called wick 17 made of an electrically conductive material can be arranged in the core component 3 'in a conventional manner, concentric to the axis 5.
  • no appreciable annular gap is formed between the core component 3 'and the casing component 2'.
  • the core component 3 ' can be provided with slots 18, preferably running in the longitudinal direction, as can be seen from FIG. 4.
  • slots 18, preferably running in the longitudinal direction as can be seen from FIG. 4.
  • the core component 3 "of the electrode 1" has blind holes 19 running radially to the axis 5 on its outside, into which so-called locking bolts 20 are inserted, which bear against the inner wall 21 of the jacket component 2.
  • These locking bolts 20 can be formed from pitch that inflates and then carbonizes during operation of the electrode 1 ′′, that is to say at higher temperatures.
  • the inflation bolts 20 are pressed against the inner wall 21 by the inflation. The carbonization then hardens them off, so that overall a non-positive connection between core component 3 "and jacket component 2 is achieved.
  • a connecting pin 22 with the same effect can be arranged concentrically to the axis 5 between the nipple 9 "and the adjacent core component 3", which in aligned blind holes 23, 24 in the end face 13 "of the nipple 9" and the adjacent end face 14 "of the core component 3 "is used.
  • Locking bolts 20 and connecting bolts 22 are therefore also electrically conductive.
  • the jacket component 2 '"and the core component 3"' of an electrode 1 '" can also be connected to one another by a dovetail connection 25.
  • the jacket component 2'" are parallel in the inner wall 21 '" Undercut grooves 26 running to the axis 5, into which dovetail-shaped webs 28 formed on the outer surface 27 of the core component 3 '' engage.
  • the individual electrodes 1 or 1 'or 1 "or 1"' are supplied individually by the manufacturer of the electrode - each with a nipple 9, 9 "- and assembled on the melting furnace to form an electrode string consisting of several electrodes by adding an electrode 1 or 1 'or 1 "or 1'” again in accordance with the erosion.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Discharge Heating (AREA)

Abstract

L'invention concerne une électrode (1) pour procédés électrométallurgiques, qui présente un constituant d'enveloppe extérieure (2) consistant en un premier matériau en carbone et un constituant central (3) consistant en un second matériau en carbone, ainsi qu'un élément de liaison (9). Le second matériau en carbone du constituant central (3) présente une résistance électrique spécifique plus basse et une masse volumique plus élevée que le premier matériau en carbone du constituant de l'enveloppe extérieure (2).
PCT/EP1999/008443 1998-11-04 1999-11-04 Electrode pour procedes electrometallurgiques WO2000027168A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU16511/00A AU1651100A (en) 1998-11-04 1999-11-04 Electrode used in electro-metallurgical processes

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19850735.6 1998-11-04
DE19850735A DE19850735C1 (de) 1998-11-04 1998-11-04 Elektrode für elektrometallurgische Verfahren

Publications (1)

Publication Number Publication Date
WO2000027168A1 true WO2000027168A1 (fr) 2000-05-11

Family

ID=7886600

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP1999/008443 WO2000027168A1 (fr) 1998-11-04 1999-11-04 Electrode pour procedes electrometallurgiques

Country Status (3)

Country Link
AU (1) AU1651100A (fr)
DE (1) DE19850735C1 (fr)
WO (1) WO2000027168A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10343687A1 (de) * 2003-09-20 2005-04-21 Sachtleben Chemie Gmbh Verfahren zur Verbesserung der Haltbarkeit von Kohlenstoff- oder Graphitelektroden durch Einsatz von TiO¶2¶-haltigen Produkten

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102009047320B3 (de) * 2009-11-30 2011-07-21 Sgl Carbon Se, 65203 Radial gradierte Elektrode mit Interface-Schicht

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB241461A (en) * 1925-04-15 1925-10-22 Carl Wilhelm Becker Improvements in or relating to furnace electrodes
US2300503A (en) * 1939-10-17 1942-11-03 Nat Carbon Co Inc Composite article
EP0142476A2 (fr) * 1983-11-11 1985-05-22 ELETTROCARBONIUM S.p.A. Electrode composite précuite en carbone pour four à arc électrique
EP0723383A1 (fr) * 1995-01-18 1996-07-24 Ucar Carbon Technology Corporation Electrode en carbone

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3422950A1 (de) * 1983-06-23 1985-01-31 Mannesmann AG, 4000 Düsseldorf Elektrode fuer lichtbogenofen mit elektrodenbruchsicherung
DE3440073A1 (de) * 1984-11-02 1986-05-07 Didier-Werke Ag, 6200 Wiesbaden Graphitelektrode fuer einen lichtbogenofen
DE4136823C2 (de) * 1991-11-08 2000-09-14 Contech C Conradty Technika Co Kohlenstoffelektrode für Lichtbogenöfen und Verfahren zum Herstellen einer solchen Kohlenstoffelektrode

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB241461A (en) * 1925-04-15 1925-10-22 Carl Wilhelm Becker Improvements in or relating to furnace electrodes
US2300503A (en) * 1939-10-17 1942-11-03 Nat Carbon Co Inc Composite article
EP0142476A2 (fr) * 1983-11-11 1985-05-22 ELETTROCARBONIUM S.p.A. Electrode composite précuite en carbone pour four à arc électrique
EP0723383A1 (fr) * 1995-01-18 1996-07-24 Ucar Carbon Technology Corporation Electrode en carbone

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10343687A1 (de) * 2003-09-20 2005-04-21 Sachtleben Chemie Gmbh Verfahren zur Verbesserung der Haltbarkeit von Kohlenstoff- oder Graphitelektroden durch Einsatz von TiO¶2¶-haltigen Produkten

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Publication number Publication date
AU1651100A (en) 2000-05-22
DE19850735C1 (de) 2000-09-21

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