EP0109839B1 - Herstellungsverfahren für Graphitelektroden - Google Patents

Herstellungsverfahren für Graphitelektroden Download PDF

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Publication number
EP0109839B1
EP0109839B1 EP19830307051 EP83307051A EP0109839B1 EP 0109839 B1 EP0109839 B1 EP 0109839B1 EP 19830307051 EP19830307051 EP 19830307051 EP 83307051 A EP83307051 A EP 83307051A EP 0109839 B1 EP0109839 B1 EP 0109839B1
Authority
EP
European Patent Office
Prior art keywords
electrode
boron
percent
anthracite coal
electric arc
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
Application number
EP19830307051
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English (en)
French (fr)
Other versions
EP0109839A2 (de
EP0109839A3 (en
Inventor
Raymond Vincent Sara
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.)
Union Carbide Corp
Original Assignee
Union Carbide Corp
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 Union Carbide Corp filed Critical Union Carbide Corp
Publication of EP0109839A2 publication Critical patent/EP0109839A2/de
Publication of EP0109839A3 publication Critical patent/EP0109839A3/en
Application granted granted Critical
Publication of EP0109839B1 publication Critical patent/EP0109839B1/de
Expired legal-status Critical Current

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    • 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

Definitions

  • the invention relates to a unique process for manufacturing graphite electrodes for electric arc furnace applications and the unique electrodes resulting from the practice of the process.
  • an electric arc furnace graphite electrode which comprises calcining a carbonaceous material selected from anthracite coal, bituminous coal, lignites, and No. 2 coke, mixing the calcined carbonaceous material with the pitch, a lubricant, and a boron source selected from elemental boron, boron carbide, silicon tetraboride and iron boride, in an amount such that the boron content is from 0.1 to 5.0 perent by weight of the graphite electrode; extruding said mixture into an electrode form; and graphitizing said electrode form.
  • No. 2 coke ordinary or regular coke which is well known to be more or less amorphous and has a dark, spongy appearance, breaking into lumps of irregular shape.
  • the boron content of the graphite electrode is preferably substantially 3 per cent by weight of the electrode.
  • This invention resides in subjecting a carbonaceous source material, other than premium petroleum coke, and preferably anthracite coal, to the action of particular sources of boron, preferably boron carbide (B 4 C), whereby the highly disordered structure of the carbonaceous material (preferably anthracite coal is transformed into one that is very graphitic in an otherwise conventional electrode manufacturing process.
  • a carbonaceous source material other than premium petroleum coke, and preferably anthracite coal
  • an electrode suitable for use in an electric arc steel melting furnace which comprises hot mixing calcined anthracite coat particles, pitch, lubricants and boron carbide, such that boron is present in the amount of substantially 3 weight percent of the electrode, extruding said mix into an electrode form and heating said shaped electrode to graphitization temperatures.
  • particles of the defined calcined non-petroleum coke carbonaceous material are mixed together with the conventional pitch binder and lubricant, and to this mixture is added the defined boron source.
  • the boron source is one which does not release a gaseous byproduct when it is to be reacted with the carbonaceous material at the graphitization step in the manufacturing process and, as defined above, is selected from elemental boron, boron carbide (B 4 C), silicon tetraboride (B 4 Si) and iron boride (FeB).
  • the B 4 C was Carborundum Company Technical Grade 325/F, containing seventy-two percent boron and a maximum particle size of 44 um.
  • the B 4 C and flour were blended in a ribbon blender for one hour prior to mixing with the other additions in a sigma-bladed heated mixer. A mix tempertaure of 158°C was achieved. The mix was then cooled to 110°C and extruded at 105°C. Extrusion pressures varied between 2689 and 3447 kPa (390 and 500 psi) for the control and between 2758 and 5576 kPa (100 and 800 psi) for the boronated mix.
  • the billets were packed with coke packing in saggers and baked at 2°C/hour to 500°C, at 10°C/hour to 900°C and held for approximately ten hours at the latter temperature.
  • Baked billets were then impregnated with Ashland 240 petroleum pitch.
  • the procedure entailed preheating the billets in an autoclave to 225°C and evacuating the chamber thereafter one-half to one hour.
  • the pitch was heated to 250°C and introduced and the system pressurized ton 698 kPa (100 psi).
  • the impregnated billets were packed in coke packaging and rebaked at 10°C/hour to 750°C and held for twenty hours at the latter temperature.
  • the graphitization process consisted of heating inductively at a rate of 200°C/hour to 2000°C and at 400°C/hour to the final temperature of 3000°C. Hold time at 3000°C was one hour. During graphitization and cooling the stock is protected from oxidation by coke packing.
  • an electrode made with boronated anthracite coal exhibits exceptional resistance to oxidation. This is an important characteristic for electrodes which must perform satisfactorily in the exacting environment of an electric arc furnace.
  • the principal impurities in anthracite coal are compounds of iron, silicon, aluminium, and titanium, and they equate to approximately ten percent ash.
  • Most naturally occurring carbonaceous materials have as impurities similar kinds of elements in varying levels. The vaporization of these materials during graphitization results in lower density, poorer structure and properties. The presence of boron has been observed to prevent their vaporization. Impurities in the boronated carbonaceous stock provide excellent protection against oxidation. This phenomenon is clearly shown as explained below in the single Figure of the drawing.
  • the single Figure of the drawing is a graph illustrating the improvement in oxidation resistance of electrodes employing in their manufacture boronated anthracite coal as compared to electrodes employing non-boronated anthracite coal.
  • the data illustrated in this graph was generated as follows: 2.54 cm (one-inch) cubes of the control and boronated anthracite coal stock were heated four hours in still air at temperatures between 800° and 1600°C. Material (carbon + ash) was weighed at the end of this time and the results are expressed as percent remaining in the Figure.
  • the oxide coating developed in the coal specimens is a very small percentage (2-5 percent) of the remaining mass. Even at 1600°C, a substantial portion of the remaining material is carbon.
  • the range of the amount of boron content to be added to the carbonaceous mix to be extruded into the finished electrode is between 0.1 and 5 percent by weight of the graphitized product, with about three percent being the preferred level of boron addition.
  • the properties of the electrodes of the invention compare very favourably with those that are available from conventional processing using premium petroleum coke.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Ceramic Products (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)
  • Furnace Details (AREA)
  • Discharge Heating (AREA)
  • Carbon And Carbon Compounds (AREA)
  • Electrodes For Compound Or Non-Metal Manufacture (AREA)

Claims (4)

1. Verfahren zur Herstellung einer elektrischen Lichtbogenofen-Graphit-Elektrode umfassend das Calcinieren eines kohlenstoffhaltigen Materials ausgewählt aus Anthrazitkohle, Fettkohle, Lignit (Braunkohlen) und Koks Nr. 2, Mischen des calcinierten kohlenstoffhaltigen Materials mit Pech, einem Gleitmittel und einer Quelle für Bor ausgewählt aus elementarem Bor, Borcarbid, Siliciumtetraborid und Eisenborid, in einer solchen Menge, daß der Borgehalt zwischen 0,1 und 5%, bezogen auf das Gewicht der Graphitelektrode, beträgt, Extrudieren dieser Mischung in eine Elektrodenform und Graphitglühen dieser Elektrodenform.
2. Verfahren nach Anspruch 1, bei dem die Quelle für Bor Borcarbid ist.
3. Verfahren nach Anspruch 1 oder 2, bei dem der Borgehalt der Graphitelektrode im wesentlichen 3 Gew.% der Elektrode beträgt.
4. Verfahren zur Herstellung einer Elektrode geeignet für die Verwendung in einem elektrischen Lichtbogenofen zum Schmelzen von Stahl, umfassend das heiße Mischen calcinierter Anthrazitkohlepartikel, Pech, Gleitmittel und Borcarbid, so daß Bor in einer Menge von im wesentlichen 3 Gew.% der Elektrode vorliegt, Extrudieren dieser Mischung in eine Elektrodenform und Erhitzen dieser geformten Elektrode auf Graphitisationstemperaturen.
EP19830307051 1982-11-19 1983-11-18 Herstellungsverfahren für Graphitelektroden Expired EP0109839B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US44309882A 1982-11-19 1982-11-19
US443098 1982-11-19

Publications (3)

Publication Number Publication Date
EP0109839A2 EP0109839A2 (de) 1984-05-30
EP0109839A3 EP0109839A3 (en) 1985-06-19
EP0109839B1 true EP0109839B1 (de) 1989-09-06

Family

ID=23759400

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19830307051 Expired EP0109839B1 (de) 1982-11-19 1983-11-18 Herstellungsverfahren für Graphitelektroden

Country Status (4)

Country Link
EP (1) EP0109839B1 (de)
JP (1) JPS59108294A (de)
DE (1) DE3380551D1 (de)
ES (1) ES527373A0 (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102015221853A1 (de) 2015-11-06 2017-05-11 Technische Universität Bergakademie Freiberg Verfahren zur Herstellung von kohlenstoffhaltigen keramischen Bauteilen

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT1396948B1 (it) * 2009-12-16 2012-12-20 Italghisa S P A Pasta elettrodica per elettrodi in grafite privi di "binder" a base idrocarburica
CN105025602A (zh) * 2015-07-13 2015-11-04 河北联冠电极股份有限公司 碳纳米超微材料大规格炭电极及其制备方法
JP6482442B2 (ja) * 2015-09-30 2019-03-13 クアーズテック株式会社 石英ガラス溶融用カーボン電極

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1285559A (fr) * 1961-03-15 1962-02-23 Union Carbide Corp Production de graphite artificiel
DE1904408A1 (de) * 1969-01-30 1970-08-06 Conradty Fa C Hoechstleistungselektrode mit stabilisiertem Lichtbogen
CH545249A (de) * 1971-04-15 1973-12-15 Lonza Ag Verfahren zur Herstellung eines isotropen Graphitmaterials
DE3116258A1 (de) * 1981-04-23 1982-11-11 C. Conradty Nürnberg GmbH & Co KG, 8505 Röthenbach Elektrode fuer lichtbogenoefen und verfahren zur deren verwendung

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102015221853A1 (de) 2015-11-06 2017-05-11 Technische Universität Bergakademie Freiberg Verfahren zur Herstellung von kohlenstoffhaltigen keramischen Bauteilen

Also Published As

Publication number Publication date
ES8407284A1 (es) 1984-08-16
JPH0137839B2 (de) 1989-08-09
DE3380551D1 (en) 1989-10-12
JPS59108294A (ja) 1984-06-22
ES527373A0 (es) 1984-08-16
EP0109839A2 (de) 1984-05-30
EP0109839A3 (en) 1985-06-19

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