EP0624655A1 - Procédé et dispositif pour le traitement de metal fondu, notamment d'acier avec une agent d'affinage - Google Patents

Procédé et dispositif pour le traitement de metal fondu, notamment d'acier avec une agent d'affinage Download PDF

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Publication number
EP0624655A1
EP0624655A1 EP94106573A EP94106573A EP0624655A1 EP 0624655 A1 EP0624655 A1 EP 0624655A1 EP 94106573 A EP94106573 A EP 94106573A EP 94106573 A EP94106573 A EP 94106573A EP 0624655 A1 EP0624655 A1 EP 0624655A1
Authority
EP
European Patent Office
Prior art keywords
oxygen
liquid oxygen
liquid
blowing nozzle
pressure
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Withdrawn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
EP94106573A
Other languages
German (de)
English (en)
Inventor
Paul Grohmann
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.)
Messer Griesheim GmbH
Original Assignee
Messer Griesheim 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 Messer Griesheim GmbH filed Critical Messer Griesheim GmbH
Publication of EP0624655A1 publication Critical patent/EP0624655A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28—Manufacture of steel in the converter
    • C21C5/30—Regulating or controlling the blowing
    • C21C5/34—Blowing through the bath
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28—Manufacture of steel in the converter
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/28—Manufacture of steel in the converter
    • C21C5/30—Regulating or controlling the blowing
    • C21C5/32—Blowing from above
    • 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
    • C22B9/05—Refining by treating with gases, e.g. gas flushing also refining by means of a material generating gas in situ
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C2250/00—Specific additives; Means for adding material different from burners or lances
    • C21C2250/04—Liquid gas
    • C21C2250/042—Liquid oxygen

Definitions

  • the invention relates to a method for treating metal melts, in particular steel melts, with a coolant.
  • oxidizing gases or gas mixtures in particular gaseous oxygen
  • the conversion process is usually carried out by converting or blowing in the gases or a combination of both.
  • a number of process names are derived from the type of oxygenation, such as. B. the LD, LDAC process or the OBM process.
  • the gaseous oxygen is fed to the pig iron for reaction through a lance or a floor purging plug.
  • the invention has for its object to provide a method for increasing the fresh speed.
  • the invention uses liquid oxygen to freshen steel, which is present as a single-phase liquid at the boiling point or below the boiling point, or as a two-phase mixture of liquid and gas.
  • Liquid oxygen has a density 855 times higher than gaseous oxygen under standard conditions.
  • oxygen is offered in a concentrated form to the reaction zone, thus increasing the reaction rate.
  • the oxygen introduced in the liquid state results in a higher total amount, by influencing the fresh process with respect to a higher fresh speed, the blowing time being reduced by up to 75% through the invention.
  • the fresh process can also be influenced by influencing the ratio of gaseous to liquid oxygen and / or by influencing the oxygen pressure and the geometry of the blow nozzle higher fresh speed can be controlled.
  • the impact energy can be influenced by varying the liquid oxygen pressure and the nozzle geometry. If necessary, it can be increased to such an extent that the jet penetrates the weld pool. In addition, the yield on alloying elements and the blowing behavior are improved and the dust ejection is reduced, since on the one hand the solubility and on the other hand the mixing of the pig iron is improved by the pulsed liquid oxygen input.
  • a blowing nozzle 1 is shown schematically, from which a jet 2 of liquid oxygen emerges at a high speed of up to 90 m / s and strikes the liquid steel bath of the converter 3.
  • the liquid oxygen is supplied through an insulated line 4 from an insulated storage container 5 for liquid oxygen.
  • This storage container 5 has the usual, unspecified pipes and valves for the removal of liquid and gaseous oxygen.
  • the liquid oxygen required for the method according to the invention is removed from the insulated storage container 5 through the line 6 and - if the pressure of the storage container 5 alone is not sufficient - is increased to a pressure of up to 50 bar by the shut-off valve 7 via the liquid oxygen pump 8.
  • the line 4 can additionally be provided with a jacket made of a cryogenic medium in order to avoid premature evaporation of the oxygen.
  • the supercooling of the oxygen takes place with liquid nitrogen or with liquid oxygen. At ambient pressure, liquid nitrogen has a boiling point that is 13 ° C lower than that of oxygen and is therefore well suited as a cooling medium.
  • the cryogenic medium liquid oxygen suitable for cooling and subcooling has an equilibrium temperature which depends on the ambient pressure. At an ambient pressure of 1 bar it is -183 ° C and decreases when the pressure drops. As shown in Fig. 1, the pressurized oxygen is therefore cooled to the required extent by heat exchange with oxygen under low pressure.
  • the liquid oxygen intended for cooling is branched off from the insulated line 4 behind the shut-off valve 7 through the line 20 and is conducted into the heat exchanger 21 via the fill level detection system 22.
  • a vacuum of up to 0.1 bar absolute is generated inside the heat exchanger 21 by means of the pump 24.
  • the boiling point of the liquid oxygen lowered in the heat exchanger 21 by up to 17 ° C so that it can serve as a cooling medium for the fresh oxygen.
  • the temperature difference between the cooling oxygen and the fresh oxygen and thus the size of the heat exchanger can be determined by the choice of the negative pressure.
  • the oxygen intended for freshening under 3 to 6 bar tank pressure (corresponds to an equilibrium temperature of -167 to -159 ° C) is passed in copper helices 25 through the heat exchanger 21 and thereby from the cooling oxygen surrounding it by 16 to 41 °, depending on the pressure ratio C cooled below its boiling temperature. As described above, this subcooling can be carried out with or without the use of a vacuum.
  • the fresh oxygen then passes through the insulated line 4 into the blowing nozzle 1, which is surrounded by insulation and a water cooling jacket 16 (FIG. 2) in order to protect it against the high heat radiation from the molten metal 3.
  • the fresh oxygen leaves the blowing nozzle 1 by being expanded.
  • the gaseous oxygen generated in the cooling of the own medium can be used for the freshening in a conventional manner or in combination with the liquid oxygen freshening.
  • 2 shows a blowing nozzle 1 designed as a 3-hole liquid oxygen blowing lance.
  • the blowing nozzle 1 has a central inflow channel 10 for liquid oxygen, which is connected to an outflow nozzle 11.
  • An outflow channel constricting the liquid oxygen is provided in the outflow nozzle 11, in which the liquid oxygen is formed into a jet before it emerges.
  • a feed 13 for is concentric with the inflow channel 10
  • Gaseous oxygen is provided, which preferably exits from three outflow openings 14 surrounding the outflow channel 12.
  • the outflow openings 14 are arranged in a nozzle block 15 which is connected to a casing tube 17 having cooling channels 16.
  • the coolant preferably water, flows in the form of a circuit cooling according to the arrows 18, 19.
  • the blowing nozzle 1 (FIG. 1) can be designed as a pure liquid oxygen blowing lance.
  • FIG. 3 shows a device for freshening up with liquid oxygen, with which the liquid oxygen is removed from the storage container 5.
  • Liquid oxygen reaches the gas phase separator 30 through the extraction line 6, the fill level detection system 31 and the insulated line 4.
  • the fill level detection system 31 automatically keeps the liquid oxygen used for freshening in the gas phase separator 30 at the desired level, for which purpose the fill level 32 is detected by means of the sensor 32.
  • the gaseous oxygen is separated from the liquid oxygen.
  • the liquid oxygen is fed via line 4 to a blowing nozzle which is designed as a multi-jet shower head. Through the shower head, the liquid oxygen is distributed in an almost pressure-free state with many jets 2 on the surface of the molten metal, thus creating a large reaction area without risk.
  • the gaseous oxygen fraction resulting from external heat is separated by the gas phase separator 30 upstream of the pump or blowing nozzle 1 and via a connected to the opening 33 line 34 in the storage container 5 or in an O2 ring line.
  • line 4 can additionally be provided with a jacket made of a cryogenic medium in order to avoid premature evaporation.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
EP94106573A 1993-05-08 1994-04-27 Procédé et dispositif pour le traitement de metal fondu, notamment d'acier avec une agent d'affinage Withdrawn EP0624655A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4315342 1993-05-08
DE19934315342 DE4315342C1 (de) 1993-05-08 1993-05-08 Verfahren zum Behandeln von Metallschmelzen, insbesondere Stahlschmelzen, mit einem Frischmittel

Publications (1)

Publication Number Publication Date
EP0624655A1 true EP0624655A1 (fr) 1994-11-17

Family

ID=6487561

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94106573A Withdrawn EP0624655A1 (fr) 1993-05-08 1994-04-27 Procédé et dispositif pour le traitement de metal fondu, notamment d'acier avec une agent d'affinage

Country Status (4)

Country Link
EP (1) EP0624655A1 (fr)
CZ (1) CZ106394A3 (fr)
DE (1) DE4315342C1 (fr)
HU (1) HU9401479D0 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10323826A1 (de) * 2003-05-23 2005-01-05 Messer Griesheim Gmbh Verfahren und Vorrichtung zum Behandeln von Metallschmelzen, insbesondere Stahlschmelzen, mit einem Frischmittel aus Sauerstoff

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19501871A1 (de) * 1995-01-23 1996-07-25 Linde Ag Verfahren zum Behandeln von Metallschmelzen mit einem Behandlungsgas
DE102009022208B4 (de) 2009-05-20 2013-03-28 Messer Group Gmbh Verfahren zum Behandeln von Metallschmelzen

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
LU31867A1 (fr) *
DE2738273A1 (de) * 1976-08-30 1978-03-02 Siderurgie Fse Inst Rech Frischverfahren mit sauerstoffeinblasung
JPS596311A (ja) * 1982-07-01 1984-01-13 Kawasaki Steel Corp 転炉の吹錬方法
EP0334037A2 (fr) * 1988-03-19 1989-09-27 Messer Griesheim Gmbh Système de refroidissement
EP0354350A2 (fr) * 1988-08-12 1990-02-14 Messer Griesheim Gmbh Procédé de coupage autogène avec de l'oxygène liquide

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
LU31867A1 (fr) *
DE2738273A1 (de) * 1976-08-30 1978-03-02 Siderurgie Fse Inst Rech Frischverfahren mit sauerstoffeinblasung
JPS596311A (ja) * 1982-07-01 1984-01-13 Kawasaki Steel Corp 転炉の吹錬方法
EP0334037A2 (fr) * 1988-03-19 1989-09-27 Messer Griesheim Gmbh Système de refroidissement
EP0354350A2 (fr) * 1988-08-12 1990-02-14 Messer Griesheim Gmbh Procédé de coupage autogène avec de l'oxygène liquide

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 8, no. 85 (C - 219)<1522> 18 April 1984 (1984-04-18) *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10323826A1 (de) * 2003-05-23 2005-01-05 Messer Griesheim Gmbh Verfahren und Vorrichtung zum Behandeln von Metallschmelzen, insbesondere Stahlschmelzen, mit einem Frischmittel aus Sauerstoff
WO2004104231A3 (fr) * 2003-05-23 2005-03-03 Messer Griesheim Gmbh Procede et dispositif pour traiter des metaux fondus au moyen d'un agent d'affinage fait d'oxygene

Also Published As

Publication number Publication date
DE4315342C1 (de) 1994-02-24
CZ106394A3 (en) 1994-12-15
HU9401479D0 (en) 1994-09-28

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