EP0056225B1 - Four de fusion à plasma - Google Patents

Four de fusion à plasma Download PDF

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Publication number
EP0056225B1
EP0056225B1 EP81890211A EP81890211A EP0056225B1 EP 0056225 B1 EP0056225 B1 EP 0056225B1 EP 81890211 A EP81890211 A EP 81890211A EP 81890211 A EP81890211 A EP 81890211A EP 0056225 B1 EP0056225 B1 EP 0056225B1
Authority
EP
European Patent Office
Prior art keywords
bottom electrode
metal layer
melting furnace
plasma melting
plasma
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
EP81890211A
Other languages
German (de)
English (en)
Other versions
EP0056225A1 (fr
Inventor
Walter Dipl.-Ing. Dr. Lugscheider
Ernst Riegler
Ernst Zajicek
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.)
Voestalpine AG
Original Assignee
Voestalpine AG
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 Voestalpine AG filed Critical Voestalpine AG
Publication of EP0056225A1 publication Critical patent/EP0056225A1/fr
Application granted granted Critical
Publication of EP0056225B1 publication Critical patent/EP0056225B1/fr
Expired legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B3/00—Hearth-type furnaces, e.g. of reverberatory type; Tank furnaces
    • F27B3/08—Hearth-type furnaces, e.g. of reverberatory type; Tank furnaces heated electrically, with or without any other source of heat
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B9/00—General processes of refining or remelting of metals; Apparatus for electroslag or arc remelting of metals
    • C22B9/16—Remelting metals
    • C22B9/22—Remelting metals with heating by wave energy or particle radiation
    • C22B9/226—Remelting metals with heating by wave energy or particle radiation by electric discharge, e.g. plasma
    • 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
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H1/00—Generating plasma; Handling plasma
    • H05H1/24—Generating plasma
    • H05H1/26—Plasma torches
    • H05H1/32—Plasma torches using an arc
    • H05H1/34—Details, e.g. electrodes, nozzles
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D99/00—Subject matter not provided for in other groups of this subclass
    • F27D99/0001—Heating elements or systems
    • F27D99/0006—Electric heating elements or system
    • F27D2099/0031—Plasma-torch heating
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H1/00—Generating plasma; Handling plasma
    • H05H1/24—Generating plasma
    • H05H1/26—Plasma torches
    • H05H1/32—Plasma torches using an arc
    • H05H1/34—Details, e.g. electrodes, nozzles
    • H05H1/3473—Safety means

Definitions

  • the invention relates to a plasma melting furnace with a water-cooled bottom electrode made of copper, a temperature sensor connected to the bottom electrode and a wear part made of steel covering the bottom electrode in the bottom of the furnace, at least one counter electrode being arranged at a distance above the wearing part to form the plasma jet.
  • the plasma jet is guided between the bottom electrode (anode) and the counter electrode (s) (cathode (s)).
  • the water-cooled bottom electrode is monitored by means of a temperature measuring device, u. the electrodes are switched off when a certain temperature is exceeded in order to prevent water from breaking through into the steel bath of the furnace.
  • the refractory lining of the furnace wears out, whereby the wearing part on the base electrode melts accordingly and shortens in the direction of the water-cooled base electrode.
  • the bottom electrode carries the current of all plasma torches.
  • the total current of the bottom electrode is between 10,000 and 50,000 A.
  • the decisive factor for the smooth functioning of the furnace is good contact of the scrap or bath with the wearing part on the bottom electrode. In the event of insufficient electrical conductivity of the contact point in the area of the bottom electrode, there is the possibility of forming secondary arcs between the scrap and the wearing part.
  • Such secondary arcs can lead to severe local overheating on the wearing part and on the bottom electrode itself, so that there is a risk of the entire bottom electrode melting through (in the manner of a flame cut) down to the water-cooled part.
  • the pressurized cooling water would penetrate into the hearth below the molten bath and lead to detonating gas explosions and thus to a hazard to the furnace and the operating personnel.
  • the process of melting the electrode takes place at a very high speed, so that the temperature measuring device is unable to give a warning message in order to shut down the system.
  • the invention has for its object to provide a furnace of the type mentioned, in which the risk of melting the bottom electrode down to its water-cooled part due to secondary arcs is avoided.
  • a metal layer of lead or zinc, cadmium, gallium, indium, tin, antimony or bismuth or their alloys is preferably provided in the two-component and multi-component system.
  • the metal layer expediently rests on the end face of the base electrode.
  • the metal layer is designed as a covering hood surrounding the upper part of the base electrode with a protruding edge flange.
  • the metal layer has a thickness between 5 and 30 mm, preferably a thickness of about 20 mm.
  • the wearing part, the metal layer and the upper part of the base electrode are combined to form a coherent structural unit by a connecting part which is preferably L-shaped in cross section.
  • Fig. 1 shows a plasma melting plant in side view and Fig. 2 in plan.
  • Fig. Shows a section through the axis of the bottom electrode of the plasma melting plant in a schematic representation.
  • An upper part 1 of a plasma melting furnace, in particular a plasma primary melting furnace, is provided with a cover 2, which is supported by a cover supporting structure 3.
  • a flue gas manifold 4 projects from the cover to a suction device, not shown.
  • the lid lifting mechanism 5 and the lid pivoting mechanism 6 are arranged laterally next to the furnace upper part 1.
  • the furnace lower part 7 rests with weighing beams 8 on raceways 9 supported on the foundation 10.
  • Each of the three plasma torches 11 is movably supported on an inclined burner mechanism 12.
  • the slag door is designated 13 and the pouring spout 14.
  • the bottom electrode 16 arranged centrally in the bottom 15 of the plasma melting furnace protrudes through the metal jacket 17 of the furnace into the interior thereof.
  • the refractory lining 18 has a recess at this point, which is closed by a steel wear part 19 against the bottom electrode 16.
  • a metal layer 21 made of a metal with low thermal conductivity and with a low melting point compared to copper and with a high enthalpy of fusion, preferably a metal layer of lead is provided, which not only covers the end face of the electrode, but also surrounds the end of the electrode peripherally.
  • An outwardly projecting edge flange 22 of this metal layer has an outer diameter which corresponds to the diameter of the wear part 19.
  • a connecting part 23 with an L-shaped cross section is provided, which is fastened on the one hand to the electrode with a weld seam 24 and on the other hand to the wearing part with a weld seam 25.
  • the wearing part, the metal layer and the bottom electrode are combined to form one structural unit.
  • a cooling water supply pipe 27 projects through which cooling water is introduced with pressure.
  • a temperature sensor 28 is installed in the peripheral side wall of the electrode and switches off the electrodes when a maximum permissible temperature is exceeded.
  • the molten steel in the furnace is designated 29.
  • the function of the metal layer is as follows: If a secondary arc is formed, this burns through the wearing part 19 at the speed of a flame cut a channel reaching to the metal layer, which in the illustrated embodiment consists of lead with a thickness of 20 mm. Starting at the interface with the lead layer, a much larger metal volume of the lead layer is melted by the thermal energy input of the secondary arc than previously in the wear part made of steel. After the molten lead is formed within a closed volume, the arc is extinguished by the liquid pressure of the molten metal in this area, thus preventing the melting process from proceeding further.
  • lead or its alloys with tin and / or zinc offers the particular advantage of being immiscible or only slightly miscible in the molten state with all steel iron materials for which a plasma furnace is used; this prevents mixing with the melt melted in the plasma melting furnace or contamination thereof.
  • the thickness of the metal layer depends on the thermodynamic properties of the metal used. A thickness of 20 mm has proven to be particularly advantageous for lead. The layer thickness can be between 5 and 30 mm.
  • the supply of molten metal in the area of the heating local secondary arc is very small, and there is no chance of the secondary arc being extinguished by molten metal and the melting channel flowing in.
  • the result of such a process is a free channel through the wearing part and the electrode material up to the cooling water area, similar to a separating cut with the result of water entering the melt.

Landscapes

  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Metallurgy (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Organic Chemistry (AREA)
  • General Engineering & Computer Science (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)
  • Gasification And Melting Of Waste (AREA)
  • Furnace Details (AREA)
  • Plasma Technology (AREA)
  • Discharge Heating (AREA)

Claims (6)

1. Four de fusion à plasma, comportant une électrode de fond (16), refroidie à l'eau, en cuivre, un détecteur de température (28) lié à l'électrode de fond et une pièce d'usure (19) en acier recouvrant l'électrode de fond (16) dans le fond (17, 18) du four ; étant précisé qu'au moins une contre- électrode (11) est disposée à une certaine distance et au-dessus de la pièce d'usure (19) pour la formation du faisceau de plasma, caractérisé en ce qu'entre l'électode de fond (16) et la pièce d'usure (19) est prévue une couche métallique (21) d'un métal de faible conductibilité thermique et de point de fusion bas par rapport au cuivre, et également à enthalpie de fusion élevée.
2. Four de fusion à plasma selon la revendication 1, caractérisé en ce qu'il est prévu une couche métallique (21) en plomb ou en zinc, en cadmium, en gallium, en indium, en étain, en antimoine ou en bismuth ou en leurs alliages en système binaire ou en système à plus de deux composants.
3. Four de fusion à plasma selon l'une quelconque des revendications 1 ou 2, caractérisé en ce que la couche métallique (21) s'appuie contre la surface frontale (20) de l'électrode de fond (16).
4. Four de fusion à plasma selon l'ensemble des revendications 1 à 3, caractérisé en ce que la couche métallique (21) est conçue comme capot de couverture entourant la partie supérieure de l'électrode de fond (16) et comportant un flasque de bordure (22) en saillie.
5. Four de fusion à plasma selon l'ensemble des revendications 1 à 4 caractérisé en ce que la couche métallique (21) présente une épaisseur entre 5 et 30 mm et de préférence une épaisseur d'environ 20 mm.
6. Four de fusion à plasma selon l'ensemble des revendications 1 à 5, caractérisé en ce que la pièce d'usure (19) la couche métallique (21) et la partie supérieure de l'électrode de fond (16) sont réunies, pour constituer un ensemble regroupé, par une pièce de liaison (23) dont la forme en coupe est de préférence la forme d'un L.
EP81890211A 1981-01-08 1981-12-28 Four de fusion à plasma Expired EP0056225B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AT3181 1981-01-08
AT31/81 1981-01-08

Publications (2)

Publication Number Publication Date
EP0056225A1 EP0056225A1 (fr) 1982-07-21
EP0056225B1 true EP0056225B1 (fr) 1984-05-23

Family

ID=3479692

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81890211A Expired EP0056225B1 (fr) 1981-01-08 1981-12-28 Four de fusion à plasma

Country Status (8)

Country Link
US (1) US4423512A (fr)
EP (1) EP0056225B1 (fr)
JP (1) JPS594630B2 (fr)
CA (1) CA1168683A (fr)
DE (1) DE3163776D1 (fr)
ES (1) ES8301089A1 (fr)
FI (1) FI814185L (fr)
ZA (1) ZA818985B (fr)

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT382595B (de) * 1982-12-22 1987-03-10 Sueddeutsche Kalkstickstoff Anlage zur erzeugung von calciumcarbid
AT375404B (de) * 1983-02-03 1984-08-10 Voest Alpine Ag Verfahren zur durchfuehrung von schmelz-, schmelzmetallurgischen und/oder reduktionsmetallurgischen prozessen in einem plasmaschmelz- ofen sowie einrichtung zur durchfuehrung des verfahrens
JPS604787A (ja) * 1983-06-22 1985-01-11 石川島播磨重工業株式会社 直流ア−ク炉の炉底電極
DE3339514A1 (de) * 1983-10-28 1985-05-09 Mannesmann AG, 4000 Düsseldorf Elektrodenanordnung in warmgaengigen gefaessen
FR2571202B1 (fr) * 1984-10-01 1987-01-09 Usinor Structure d'electrode pour bain de metal en fusion
DE3543278C1 (de) * 1985-12-05 1987-07-02 Mannesmann Ag Ofengefaess eines Gleichstrom-Lichtbogenofens mit Bodenelektroden sowie zugehoerige Bodenelektrode
AT385520B (de) * 1986-07-22 1988-04-11 Voest Alpine Ag Verfahren zur gewinnung von kupfer sowie ofen zur durchfuehrung des verfahrens
DE4026897C2 (de) * 1990-08-23 1994-05-05 Mannesmann Ag Metallische Bodenelektrode für metallurgische Gefäße
FR2682003B1 (fr) * 1991-09-30 1997-04-30 Siderurgie Fse Inst Rech Electrode de paroi pour four metallurgique electrique a courant continu.
FR2711233B1 (fr) * 1993-10-15 1995-12-29 Usinor Sacilor Récipient métallurgique comportant une électrode de sole.

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1271093A (en) * 1917-03-01 1918-07-02 Frederick T Snyder Electric-furnace contact.
US3496280A (en) * 1968-08-15 1970-02-17 United States Steel Corp Method of refining steel in plasma-arc remelting
JPS5031524B1 (fr) * 1969-12-25 1975-10-13
US3717713A (en) * 1971-02-18 1973-02-20 M Schlienger Arc furnace crucible
DE2142331A1 (de) * 1971-08-24 1973-03-08 Messer Griesheim Gmbh Duesenkoerper fuer plasmaschneid- und/ oder schweissbrenner
US4101725A (en) * 1976-08-16 1978-07-18 Nikolai Semenovich Shelepov Hearth electrode for melting furnaces
DE2715697C3 (de) * 1977-04-07 1981-11-05 Šelepov, Nikolaj Semenovič Plasmalichtbogenschmelzofen
US4137422A (en) * 1977-04-19 1979-01-30 Barbashin Oleg A Airtight metal melting furnace
US4133987A (en) * 1977-12-07 1979-01-09 Institut Elektrosvarki Imeni E.O. Patona Adakemii Nauk Electrode assembly for plasma arc torches

Also Published As

Publication number Publication date
JPS57142476A (en) 1982-09-03
DE3163776D1 (en) 1984-06-28
ES508569A0 (es) 1982-11-01
ZA818985B (en) 1983-03-30
JPS594630B2 (ja) 1984-01-31
ES8301089A1 (es) 1982-11-01
US4423512A (en) 1983-12-27
CA1168683A (fr) 1984-06-05
EP0056225A1 (fr) 1982-07-21
FI814185L (fi) 1982-07-09

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