EP0109839A2 - Herstellungsverfahren für Graphitelektroden - Google Patents

Herstellungsverfahren für Graphitelektroden Download PDF

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Publication number
EP0109839A2
EP0109839A2 EP83307051A EP83307051A EP0109839A2 EP 0109839 A2 EP0109839 A2 EP 0109839A2 EP 83307051 A EP83307051 A EP 83307051A EP 83307051 A EP83307051 A EP 83307051A EP 0109839 A2 EP0109839 A2 EP 0109839A2
Authority
EP
European Patent Office
Prior art keywords
electrode
boron
boronated
graphitized
anthracite coal
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
EP83307051A
Other languages
English (en)
French (fr)
Other versions
EP0109839A3 (en
EP0109839B1 (de
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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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

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.
  • the principal object of this invention is to provide a method for manufacturing electrodes acceptable for use in electric arc furnaces in which the starting carbonaceous source material is not necessarily entirely premium grade petroleum coke.
  • This invention resides in subjecting a carbonaceous source material, other than premium petroleum coke,-and preferably anthracite coal, to the action of elemental boron or a boron compound, preferably boron carbide (B 4 C), whereby the highly disordered structure of the 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
  • 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.
  • particles of a non-petroleum coke carbonaceous material are mixed together with the conventional pitch binder and lubricants, and to this mixture is added elemental boron or a boron containing compound.
  • Acceptable carbonaceous source materials other than anthracite coal are bituminous coal, lignites and No. 2 and No. 3 cokes.
  • the boron source is one which does not release a gaseous by-product when it is to be reacted with the carbonaceous material at the graphitization step in the manufacturing process.
  • Such boron sources are elemental boron, boron carbide (B 4 C), silicon tetraboride (B 4 Si) and iron boride (FeB).
  • the boron material can be incorporated with the carbonaceous material during calcination and in this procedure the boron compound may be an oxide such as boric acid (H 3 B0 3 ) or boric oxide (B 2 0 3 ) since the gaseous by-product formed would have no effect on the structural integrity of the finished electrode.
  • the boron compound may be an oxide such as boric acid (H 3 B0 3 ) or boric oxide (B 2 0 3 ) since the gaseous by-product formed would have no effect on the structural integrity of the finished electrode.
  • the B 4 C was Carborundum Company Technical Grade 325/F, containing seventy-two percent boron and a maximum particle size of 44 ⁇ m.
  • 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 temperature of 158°C was achieved. The mix was then cooled to 110°C.and extruded at 105°C. Extrusion pressures varied between 390 and 500 psi for the control and between 400 and 800 psi for the boronated mix. The higher extrusion pressure for the boron-containing mix indicates that insufficient binder was present, which should probably be detremental to physical properties, especially strength. However, in spite of this, as shown in Table II, the boronated electrode had significantly higher strength than the control electrode.. Eight billets measuring six inches diameter by eighteen inches long were formed from each 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 for one-half to one hour.
  • the pitch was heated to 250°C and introduced and the system pressurized to 100 psi.
  • the impregnated billets were packed in coke packing 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, aluminum, 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 data illustrated in this graph was generated as follows:
  • 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 favorably with those that are available from conventional processing using premium petroleum coke.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Ceramic Products (AREA)
  • Furnace Details (AREA)
  • Discharge Heating (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)
  • Carbon And Carbon Compounds (AREA)
  • Electrodes For Compound Or Non-Metal Manufacture (AREA)
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 true EP0109839A2 (de) 1984-05-30
EP0109839A3 EP0109839A3 (en) 1985-06-19
EP0109839B1 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
DE102015221853B4 (de) 2015-11-06 2019-05-16 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
DE102015221853B4 (de) 2015-11-06 2019-05-16 Technische Universität Bergakademie Freiberg Verfahren zur Herstellung von kohlenstoffhaltigen keramischen Bauteilen

Also Published As

Publication number Publication date
EP0109839A3 (en) 1985-06-19
EP0109839B1 (de) 1989-09-06
ES8407284A1 (es) 1984-08-16
DE3380551D1 (en) 1989-10-12
ES527373A0 (es) 1984-08-16
JPS59108294A (ja) 1984-06-22
JPH0137839B2 (de) 1989-08-09

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