EP0452599A2 - Lichtbogenofen mit sich verzehrender Elektrode - Google Patents

Lichtbogenofen mit sich verzehrender Elektrode Download PDF

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Publication number
EP0452599A2
EP0452599A2 EP90403152A EP90403152A EP0452599A2 EP 0452599 A2 EP0452599 A2 EP 0452599A2 EP 90403152 A EP90403152 A EP 90403152A EP 90403152 A EP90403152 A EP 90403152A EP 0452599 A2 EP0452599 A2 EP 0452599A2
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EP
European Patent Office
Prior art keywords
sleeve
upper electrode
electrode
arc
gas
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.)
Withdrawn
Application number
EP90403152A
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English (en)
French (fr)
Other versions
EP0452599A3 (en
Inventor
Michel G. Drouet
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.)
Hydro Quebec
Original Assignee
Hydro Quebec
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 Hydro Quebec filed Critical Hydro Quebec
Publication of EP0452599A2 publication Critical patent/EP0452599A2/de
Publication of EP0452599A3 publication Critical patent/EP0452599A3/fr
Withdrawn legal-status Critical Current

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Classifications

    • 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
    • F27D11/00—Arrangement of elements for electric heating in or on furnaces
    • F27D11/08—Heating by electric discharge, e.g. arc discharge
    • F27D11/10—Disposition of electrodes
    • 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

Definitions

  • the present invention relates to an improved arc furnace, comprising a consumable electrode and intended to be used in the processing of ores or other metallic or non-metallic compounds, at very high temperatures, with the aim of transforming them physically or chemically.
  • Arc furnaces are very well-known devices, which have been the subject of much research and development in recent decades. By definition, such furnaces use a heat-generating arc column, created between a set of electrodes, to heat the ores or compounds to be treated at very high temperatures and thus make it possible to obtain reactions which could not be obtained. other.
  • the arc column usually consists of a mixture of excited and / or dissociated molecules, positively charged ions and free electrons obtained from a gas (called "plasma gas”) subjected to partial ionization by means of 'an electric arc (usually direct current) formed between the two electrodes.
  • plasma gas a gas subjected to partial ionization by means of 'an electric arc (usually direct current) formed between the two electrodes.
  • the arc furnace to which the present invention applies, is of the type comprising an upper electrode situated in the upper part of a sleeve, and a lower electrode in electrical contact with the conductive molten ore collected in a crucible under the electrode superior.
  • the arc column which forms between the upper and lower electrodes ensures the melting of the pulverulent material introduced into the sleeve and causes the desired physical and chemical transformation, the molten material subsequently falling into the crucible.
  • Such an oven is described for example in American patent application No. 399,997, filed on August 29, 1989 and assigned to the Applicant.
  • the arc furnaces of the type described above, to which the invention applies usually employ so-called “non-consumable” electrodes.
  • the duration of such "non-consumable” electrodes is quite short, since it varies between three and a thousand hours depending on the operating conditions. Replacing these electrodes is expensive and it often happens that the process has to be interrupted.
  • non-consumable electrodes must also be cooled with water to avoid excessive erosion. This makes them prone to water leaks which can be the source of explosions due to the reaction of the water and the material under treatment at high temperature.
  • the present invention relates to an arc furnace of the type described above, which uses a consumable electrode which, on the one hand, it is not necessary to cool with water, and which, on the other hand, can be advanced as it wears out, thus increasing the operating period of the oven.
  • the consumable electrode used in the oven according to the invention is preferably made of graphite.
  • the oven comprises a vertical sleeve, electrically insulated, and provided, at its upper end, with a first electrode which, as previously indicated, can be made of graphite and be of conventional structure, which serves to maintain an arc column generated between its lower end and a bath of molten material contained in the crucible of the furnace.
  • This first electrode can be lowered so as to be brought closer to the surface of the bath to allow easy striking of the arc. Once this has started, the electrode is reassembled in the chamber defined by the sleeve.
  • the material to be treated is introduced, in powder form, inside the sleeve at the top thereof, next to the electrode.
  • the material is projected by centrifugation against the internal wall of the sleeve by a tangential jet of gas injected inside the sleeve so as to provide a coating, essentially cylindrical and uniform, of particles falling into the sleeve. These particles completely cover the internal wall of the sleeve and protect it while being simultaneously treated by the heat given off by the arc column.
  • the oven further includes a crucible located under the sleeve to collect the treated molten particles which trickle from the lower end of the sleeve.
  • a second electrode is provided at the bottom of the crucible to complete the electrical circuit formed by the graphite electrode, the arc, the conductive molten bath and the external electrical circuit connected to a source of electrical energy.
  • consumable electrodes preferably graphite
  • tools when used in arc furnaces for different applications at power levels up to 50 megawatts.
  • the use of such electrodes has hitherto never been suggested for arc furnaces having the configuration described above.
  • this furnace is characterized in that the upper electrode is made of a consumable material.
  • the electrode according to the invention may include a bore allowing the temporary or continuous supply of a stream of plasma gas, such as argon, to facilitate the initiation of the arc or even allow a more stable operation of the arc.
  • a stream of plasma gas such as argon
  • the positioning means preferably comprise means for advancing the upper electrode and means for monitoring this advancement, so as to ensure that the upper electrode is advanced as it wears out. that the length of the arc remains constant.
  • these means for monitoring the progress of the upper electrode may include an assembly formed by a detector radiation, an optical tube connecting the detector and said inner wall, and a gas supply connected to the optical tube to prevent obstruction by particles falling into the sleeve, and be arranged so that the detector can detect the presence or absence of radiation emitted by the arc or by the upper electrode in the direction of the optical tube and thus allow the control of said advancement means.
  • the progress control means may comprise two such assemblies aiming at two points arranged vertically in different positions so that one of these assemblies can detect the radiation emitted by the arc, and the other assembly, the radiation emitted by the upper electrode.
  • these same means for controlling the progress of the upper electrode may include means for weighing the upper electrode and means for measuring the length of the upper electrode outside the oven so that the vertical position of the upper electrode inside the sleeve can be calculated, the upper electrode being made of a material of known density.
  • Figure 1 illustrates the upper electrode and the supply system of an arc furnace 10 according to the invention.
  • This upper electrode 20 can be moved using a roller drive system 26, so that its position can be adjusted in the vertical direction.
  • the upper electrode 20 is a solid electrode of graphite or any other similar consumable material.
  • the material 12 which is to be treated in the oven enters via supply lines 24 provided around the upper periphery of the sleeve 14. Holes below called “optical tubes” 32 are oriented towards the lower end 21 of the electrode 20. Any possible light emitted by the end 21 passes through the tubes 32 to reach the detectors 28. A continuous supply of gas 30 is connected to the tubes 32 to ensure that the ends of these tubes 32 which open onto the wall cylindrical 18 are not obstructed by the material 12. An alarm system (not shown) is connected to the gas supply 30, and is triggered when the gas flow falls below a determined control value.
  • the detectors 28 can be fitted with optical filters to filter or reduce the light intensity of the arc 11.
  • the plate 16 forming the upper end of the sleeve 14, is provided with an annular channel 17, into which is injected, in several places, a propellant gas from another supply in gas 22.
  • This upper end plate 16 is made of steel and resistant to wear, and the channel 17 is shaped inside the sleeve, that is to say under the plate.
  • the gas from the supply 22 is tangentially injected into the annular channel at four points equally spaced from one another.
  • the injected propellant gas drives the material to be treated 12 in a rotational movement and projects the material thus accelerated by centrifugal force against the cylindrical wall 18 of the sleeve.
  • the material 12 is introduced into the upper part of the sleeve, dropping it at four equidistant points 24 (two of these points being illustrated in Figure 1).
  • the material 12 thus introduced is entrained and forms a film or coating on the cylindrical wall 18 of the sleeve, as illustrated in FIG. 1, and this coating is heated by the radiation from the arc 11.
  • the arc 11 is formed between the upper electrode 20 and the molten material 12 collected in a crucible (not shown), under the sleeve 14.
  • a bottom electrode is connected electrically to the molten material 12 and to a source of electrical energy (not shown), forming a circuit between the electrode 20 and the molten material 12 in the crucible.
  • the material 12 in the crucible is kept hot by the passage of the current going to the electrode at the bottom thereof.
  • the drive system 26 is used to lower the electrode 20, so that its lower end 21 approaches either the bottom electrode or the molten material which has been heated to beforehand in the crucible. Once the electrode 20 has been lowered, the arc 11 can easily be struck. The electrode 20 can then be raised to its normal position which is that shown in FIG. 1.
  • the position of the end 21 of the electrode 20, which slides through the upper end 16 of the sleeve 14, can be adjusted to ensure that there is adequate energy transfer to the coating of material 12.
  • this adjustment can be controlled by the light detectors 28, one of them picking up the radiation from the arc 11, and the other picking up the radiation emitted by the red-hot end 21 of the electrode 20.
  • the optical tubes 32 passing through the external wall of the sleeve 14 and through the cylindrical wall internal 18 thereof, create a path to radiation from the arc 11 and the end 21 of the electrode to the detectors.
  • the light that strikes the lower of the two detectors 28 can be attenuated by a high density filter 29.
  • Each light detector 28 emits a voltage signal V1 and V2 which is proportional to the light intensity striking its surface.
  • Each voltage signal is compared to a reference voltage by comparators (not shown), the output signals of which act on control means making it possible to raise or lower the electrode 20 by means of the drive system 26 .
  • Figure 3 shows the various situations that can be encountered in the form of phases A, B and C.
  • the two optical tubes 32 point towards the light arc 11.
  • the two voltage signals V1 and V2 are greater than their respective reference voltages and, consequently, a signal is sent to the control means to lower the electrode 20.
  • the two optical tubes 32 point towards the light electrode 21. In this case, the two signals voltage V1 and V2 are lower than their respective reference voltages. It follows that a signal is sent to the control means to lift the electrode.
  • the upper optical tube 32 points towards the end of the electrode 21, while the lower optical tube 32 points towards the light arc 11. In this case, no signal is sent, and the electrode 20 remains stationary.
  • the positioning means may include means for weighing the electrode 20 and means for measuring the height thereof outside the furnace 10. By knowing the density of the electrode 20 , of uniform construction, the position of the end 21 can be calculated and adjusted by means of the actuation system 26, as required.
  • the illustrated means for introducing the material 12 are the supply lines 24 to the through which the material 12 falls, it is also possible to inject this material 12 by using the gas supply 22 or separately from it but in a similar tangential direction.
  • the electrode 20 may be of a solid construction, but it may also be provided with a central bore, of small diameter, into which a gas serving to stabilize the arc can be injected, this gas preferably being, argon.
  • the gas thus injected can also be chosen so as to participate in the reaction occurring inside the furnace.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Discharge Heating (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)
  • Furnace Details (AREA)
EP19900403152 1990-04-20 1990-11-07 Arc furnace with consumable electrode Withdrawn EP0452599A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US07/512,166 US5046145A (en) 1990-04-20 1990-04-20 Improved arc reactor with advanceable electrode
US512166 1990-04-20

Publications (2)

Publication Number Publication Date
EP0452599A2 true EP0452599A2 (de) 1991-10-23
EP0452599A3 EP0452599A3 (en) 1993-02-24

Family

ID=24037963

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19900403152 Withdrawn EP0452599A3 (en) 1990-04-20 1990-11-07 Arc furnace with consumable electrode

Country Status (4)

Country Link
US (1) US5046145A (de)
EP (1) EP0452599A3 (de)
JP (1) JPH044596A (de)
CA (1) CA2030671C (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19838683A1 (de) * 1998-08-26 2000-03-02 Schuetz Dental Gmbh Lichtbogen-Schmelzofen
KR100487769B1 (ko) * 2000-10-27 2005-05-03 주식회사 포스코 전기로의 도체 분말 투입장치 및 도체 분말을 이용한스크랩 용융방법

Families Citing this family (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2047807A1 (fr) * 1991-07-24 1993-01-25 My Dung Nguyen Handfield Vitrification des cendres
US5233153A (en) * 1992-01-10 1993-08-03 Edo Corporation Method of plasma spraying of polymer compositions onto a target surface
JP3121743B2 (ja) * 1994-08-10 2001-01-09 日立造船株式会社 プラズマ式溶融方法
US7781947B2 (en) * 2004-02-12 2010-08-24 Mattson Technology Canada, Inc. Apparatus and methods for producing electromagnetic radiation
US20120048723A1 (en) * 2010-08-24 2012-03-01 Varian Semiconductor Equipment Associates, Inc. Sputter target feed system
US10138378B2 (en) 2014-01-30 2018-11-27 Monolith Materials, Inc. Plasma gas throat assembly and method
US11939477B2 (en) 2014-01-30 2024-03-26 Monolith Materials, Inc. High temperature heat integration method of making carbon black
US10370539B2 (en) 2014-01-30 2019-08-06 Monolith Materials, Inc. System for high temperature chemical processing
US10100200B2 (en) 2014-01-30 2018-10-16 Monolith Materials, Inc. Use of feedstock in carbon black plasma process
EP3100597B1 (de) 2014-01-31 2023-06-07 Monolith Materials, Inc. Plasmabrenner mit graphitelektroden
US11987712B2 (en) 2015-02-03 2024-05-21 Monolith Materials, Inc. Carbon black generating system
US10618026B2 (en) 2015-02-03 2020-04-14 Monolith Materials, Inc. Regenerative cooling method and apparatus
MX2018001259A (es) 2015-07-29 2018-04-20 Monolith Mat Inc Aparato y método de diseño de energía eléctrica para soplete de plasma cc.
CN108290738A (zh) 2015-09-09 2018-07-17 巨石材料公司 圆形多层石墨烯
JP6974307B2 (ja) 2015-09-14 2021-12-01 モノリス マテリアルズ インコーポレイテッド 天然ガス由来のカーボンブラック
CA3060482C (en) 2016-04-29 2023-04-11 Monolith Materials, Inc. Secondary heat addition to particle production process and apparatus
ES2983689T3 (es) 2016-04-29 2024-10-24 Monolith Mat Inc Método y aparato del aguijón de la antorcha
EP3592810A4 (de) 2017-03-08 2021-01-27 Monolith Materials, Inc. Systeme und verfahren zur herstellung von kohlenstoffteilchen mit wärmetransfergas
KR20190138862A (ko) 2017-04-20 2019-12-16 모놀리스 머티어리얼스 인코포레이티드 입자 시스템 및 방법
EP3676220A4 (de) 2017-08-28 2021-03-31 Monolith Materials, Inc. Systeme und verfahren zur partikelerzeugung
CA3116989C (en) 2017-10-24 2024-04-02 Monolith Materials, Inc. Particle systems and methods
CN111811268B (zh) * 2020-06-16 2021-04-23 西安交通大学 一种分层组合电极矿热熔炼炉及其控制方法
CN111811252B (zh) * 2020-06-16 2021-04-27 西安交通大学 一种三相分层组合电极矿热熔炼炉及其控制方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1390353A (en) * 1971-02-16 1975-04-09 Tetronics Research Dev Co Ltd High temperature treatment of materials
EP0019362A1 (de) * 1979-04-17 1980-11-26 Plasma Holdings N.V. Verfahren und Vorrichtung zum Behandeln von Material mit einem Tieftemperatur-Plasma
EP0071351A1 (de) * 1981-07-30 1983-02-09 Hydro-Quebec Plasmareaktor mit übertragendem Lichtbogen zur chemischen und metallurgischen Verwendung
EP0282310A2 (de) * 1987-03-11 1988-09-14 James A. Browning Verfahren und Apparat zum Hochleistungsplasmaspritzen
USRE32908E (en) * 1984-09-27 1989-04-18 Regents Of The University Of Minnesota Method of utilizing a plasma column

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NL6700212A (de) * 1967-01-06 1968-07-08
US3944412A (en) * 1974-09-18 1976-03-16 Hsin Liu Method for recovering metals
JPS5457244A (en) * 1977-10-14 1979-05-08 Hitachi Ltd Method of electronically melting slag
NO141183C (no) * 1977-12-06 1980-01-23 Sintef Plasmabrenner.
JPS561375A (en) * 1979-06-18 1981-01-09 Seiko Epson Corp Multitime display watch
JPS6053088A (ja) * 1983-09-02 1985-03-26 Nec Corp 半導体装置
US4818837A (en) * 1984-09-27 1989-04-04 Regents Of The University Of Minnesota Multiple arc plasma device with continuous gas jet
US4864096A (en) * 1987-12-18 1989-09-05 Westinghouse Electric Corp. Transfer arc torch and reactor vessel

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1390353A (en) * 1971-02-16 1975-04-09 Tetronics Research Dev Co Ltd High temperature treatment of materials
EP0019362A1 (de) * 1979-04-17 1980-11-26 Plasma Holdings N.V. Verfahren und Vorrichtung zum Behandeln von Material mit einem Tieftemperatur-Plasma
EP0071351A1 (de) * 1981-07-30 1983-02-09 Hydro-Quebec Plasmareaktor mit übertragendem Lichtbogen zur chemischen und metallurgischen Verwendung
USRE32908E (en) * 1984-09-27 1989-04-18 Regents Of The University Of Minnesota Method of utilizing a plasma column
EP0282310A2 (de) * 1987-03-11 1988-09-14 James A. Browning Verfahren und Apparat zum Hochleistungsplasmaspritzen

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19838683A1 (de) * 1998-08-26 2000-03-02 Schuetz Dental Gmbh Lichtbogen-Schmelzofen
KR100487769B1 (ko) * 2000-10-27 2005-05-03 주식회사 포스코 전기로의 도체 분말 투입장치 및 도체 분말을 이용한스크랩 용융방법

Also Published As

Publication number Publication date
CA2030671C (fr) 1999-07-06
CA2030671A1 (fr) 1991-10-21
EP0452599A3 (en) 1993-02-24
JPH044596A (ja) 1992-01-09
US5046145A (en) 1991-09-03

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