EP0334007A1 - Procédé pour diminuer l'usure d'électrodes en graphite - Google Patents

Procédé pour diminuer l'usure d'électrodes en graphite Download PDF

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Publication number
EP0334007A1
EP0334007A1 EP89102063A EP89102063A EP0334007A1 EP 0334007 A1 EP0334007 A1 EP 0334007A1 EP 89102063 A EP89102063 A EP 89102063A EP 89102063 A EP89102063 A EP 89102063A EP 0334007 A1 EP0334007 A1 EP 0334007A1
Authority
EP
European Patent Office
Prior art keywords
electrode
lateral surface
electrodes
coating
graphite
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
EP89102063A
Other languages
German (de)
English (en)
Other versions
EP0334007B1 (fr
Inventor
Hubert Dipl.-Chem. Dr. Jäger
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.)
Sigri GmbH
Original Assignee
Sigri 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 Sigri GmbH filed Critical Sigri GmbH
Publication of EP0334007A1 publication Critical patent/EP0334007A1/fr
Application granted granted Critical
Publication of EP0334007B1 publication Critical patent/EP0334007B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • H05B7/12—Arrangements for cooling, sealing or protecting electrodes

Definitions

  • the invention relates to a method for reducing the burn-up of graphite electrodes in their use in an electric arc furnace by coating the lateral surface with an oxidation-resistant protective layer.
  • the graphite electrodes used in arc furnaces, particularly for the production of steel, suspended above the furnace lid on a supporting device, are heated to temperatures at which carbon with the oxygen of the surrounding air is heated by the heat energy generated in the arc and the development of Joule heat inside the electrodes Carbon oxides reacts.
  • the reactions which are referred to simply as burn-up, are not limited to the lateral surface of the cylindrical electrode, but extend below about 1000 ° C. almost over the entire volume of the electrode accessible through the pore system.
  • the burning of the lateral surface causes a reduction in the diameter of the electrode, the burning in the interior of the electrode also a substantial disruption of the structure, whereby smaller structural elements are loosened and splintered.
  • Electrode consumption could be reduced by up to 15% through the cooling process in some furnaces, in other furnaces the consumption reduction was much lower, in some cases even the amount of mantle erosion increased.
  • causes of the different results are probably instabilities of the water films and steam mantles, triggered for example by thermal convection currents, and the adsorption of water in the pore system of the graphite electrode. The adsorbed water reacts with the carbon at higher temperatures and produces the sponge-like soft zones typical of wet electrodes.
  • the invention has for its object to produce on the lateral surface of graphite electrodes by simple technical means an oxidation-resistant protective layer, which protects the electrode under all loads in the electric arc furnace effectively against the attack of atmospheric oxygen.
  • the object is achieved by a method of the type mentioned above in that the aqueous solution of at least one, at elevated temperature glassy films forming salt is sprayed onto the lateral surface of the electrode below the contact jaws.
  • Graphite electrodes are at room temperature in the solution immersed one or more salts or the solution is applied by brushing or spraying on the lateral surface. The electrodes are then dried and heated to about 500 to 600 ° C, the heating rate is about 60 to 600 K / h. This forms a water-insoluble, firmly anchored in the pores oxidation resistant film.
  • the coating solution to the lateral surface, it is expedient to use one or more nozzle rings, which are fastened to the electrode holder underneath the contact jaws and enclose the electrode strand. After each of the above-described displacement of the electrode strand in the axial direction, the free portion of the electrode is sprayed between the contact shoe and furnace cover with the coating solution, wherein the duration of the coating depends on the growth of the protective layer.
  • Suitable coating agents are in principle all salts which are soluble in water and, after evaporation of the solvent at elevated temperatures, form closed films which are resistant to oxidation and impermeable to fluids.
  • suitable salts are the abovementioned phosphates, borates and silicates.
  • the aqueous coating solution should contain about 15 to 25% monoaluminum phosphate, and to form a closed, graphite electrode protective layer it is desirable to use 300 to 500 g / m2 of monoaluminum phosphate, which corresponds to about 1 to 3 liters / m2 of coating solution.
  • the method enables the coating of graphite electrodes with simple means, as used in the water cooling of the electrode sheath, and the production of layers, which have a much better protective effect than the "water layers".
  • the application of the method is not limited to graphite electrodes, but also extends to carbon electrodes, which are mainly used in thermal reduction furnaces.
  • the sprayed amount of monoaluminum phosphate was about 400 g / m2.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Discharge Heating (AREA)
  • Coating By Spraying Or Casting (AREA)
EP89102063A 1988-03-19 1989-02-07 Procédé pour diminuer l'usure d'électrodes en graphite Expired - Lifetime EP0334007B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3809361A DE3809361A1 (de) 1988-03-19 1988-03-19 Verfahren zur verringerung des abbrands von graphitelektroden
DE3809361 1988-03-19

Publications (2)

Publication Number Publication Date
EP0334007A1 true EP0334007A1 (fr) 1989-09-27
EP0334007B1 EP0334007B1 (fr) 1991-04-10

Family

ID=6350232

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89102063A Expired - Lifetime EP0334007B1 (fr) 1988-03-19 1989-02-07 Procédé pour diminuer l'usure d'électrodes en graphite

Country Status (2)

Country Link
EP (1) EP0334007B1 (fr)
DE (2) DE3809361A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5407290A (en) * 1992-06-18 1995-04-18 Societe Des Electrodes Et Connecting joint for electric furnace electrodes
WO2020081155A1 (fr) 2018-10-15 2020-04-23 Chemtreat, Inc. Procédés de protection d'électrodes de four avec un liquide de refroidissement qui contient un additif
US11979968B2 (en) 2018-10-15 2024-05-07 Chemtreat, Inc. Spray cooling furnace electrodes with a cooling liquid that contains surfactants

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB891273A (en) * 1960-05-30 1962-03-14 United Steel Companies Ltd Improvements relating to electric arc furnaces
DE3315975A1 (de) * 1982-06-07 1983-12-08 VEB Elektrokohle Lichtenberg, DDR 1130 Berlin Verfahren zur herstellung schutzbeschichteter graphitelektroden
FR2531301A1 (fr) * 1982-08-02 1984-02-03 Nalco Chemical Co Electrode consommable electriquement conductrice, composition utile pour former un revetement dielectrique sur les electrodes en carbone et en graphite et procede de protection d'electrodes en carbone et en graphite
JPS5951496A (ja) * 1982-09-18 1984-03-24 松下電器産業株式会社 カ−トリツジヒ−タの製造方法
EP0223205A1 (fr) * 1985-11-13 1987-05-27 Union Carbide Corporation Electrode en graphite ou en carbone à oxydation retardée et procédé de fabrication de l'électrode
WO1988007315A1 (fr) * 1987-03-17 1988-09-22 Nippon Carbon Co., Ltd. Procede de fusion et de raffinage de metaux, et dispositif de refroidissement des electrodes utilisees a cet effet

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB891273A (en) * 1960-05-30 1962-03-14 United Steel Companies Ltd Improvements relating to electric arc furnaces
DE3315975A1 (de) * 1982-06-07 1983-12-08 VEB Elektrokohle Lichtenberg, DDR 1130 Berlin Verfahren zur herstellung schutzbeschichteter graphitelektroden
FR2531301A1 (fr) * 1982-08-02 1984-02-03 Nalco Chemical Co Electrode consommable electriquement conductrice, composition utile pour former un revetement dielectrique sur les electrodes en carbone et en graphite et procede de protection d'electrodes en carbone et en graphite
JPS5951496A (ja) * 1982-09-18 1984-03-24 松下電器産業株式会社 カ−トリツジヒ−タの製造方法
EP0223205A1 (fr) * 1985-11-13 1987-05-27 Union Carbide Corporation Electrode en graphite ou en carbone à oxydation retardée et procédé de fabrication de l'électrode
WO1988007315A1 (fr) * 1987-03-17 1988-09-22 Nippon Carbon Co., Ltd. Procede de fusion et de raffinage de metaux, et dispositif de refroidissement des electrodes utilisees a cet effet

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5407290A (en) * 1992-06-18 1995-04-18 Societe Des Electrodes Et Connecting joint for electric furnace electrodes
WO2020081155A1 (fr) 2018-10-15 2020-04-23 Chemtreat, Inc. Procédés de protection d'électrodes de four avec un liquide de refroidissement qui contient un additif
US20200196404A1 (en) * 2018-10-15 2020-06-18 Chemtreat, Inc. Methods of protecting furnace electrodes with cooling liquid that contains an additive
US10694592B1 (en) * 2018-10-15 2020-06-23 Chemtreat, Inc. Methods of protecting furnace electrodes with cooling liquid that contains an additive
US11140755B2 (en) 2018-10-15 2021-10-05 Chemtreat, Inc. Methods of protecting furnace electrodes with cooling liquid that contains an additive
EP3815465A4 (fr) * 2018-10-15 2022-01-05 Chemtreat, Inc. Procédés de protection d'électrodes de four avec un liquide de refroidissement qui contient un additif
US11653426B2 (en) 2018-10-15 2023-05-16 Chemtreat, Inc. Methods of protecting furnace electrodes with cooling liquid that contains an additive
EP4216672A1 (fr) 2018-10-15 2023-07-26 Chemtreat, Inc. Procédés de protection d'électrodes de four avec un liquide de refroidissement qui contient un additif
US11979968B2 (en) 2018-10-15 2024-05-07 Chemtreat, Inc. Spray cooling furnace electrodes with a cooling liquid that contains surfactants
US12150230B2 (en) 2018-10-15 2024-11-19 Chemtreat, Inc. Methods of protecting furnace electrodes with cooling liquid that contains an additive
US20250040003A1 (en) * 2018-10-15 2025-01-30 Chemtreat, Inc. Methods of protecting furnace electrodes with cooling liquid that contains an additive

Also Published As

Publication number Publication date
EP0334007B1 (fr) 1991-04-10
DE58900079D1 (de) 1991-05-16
DE3809361A1 (de) 1989-09-28

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