EP0144773A1 - Dispositif pour désulfurer du fer liquide - Google Patents

Dispositif pour désulfurer du fer liquide Download PDF

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Publication number
EP0144773A1
EP0144773A1 EP84113394A EP84113394A EP0144773A1 EP 0144773 A1 EP0144773 A1 EP 0144773A1 EP 84113394 A EP84113394 A EP 84113394A EP 84113394 A EP84113394 A EP 84113394A EP 0144773 A1 EP0144773 A1 EP 0144773A1
Authority
EP
European Patent Office
Prior art keywords
lance
cross
section
mouth
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Withdrawn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
EP84113394A
Other languages
German (de)
English (en)
Inventor
André Bock
Jean Peckels
Antoine Schaaf
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.)
Arcelor Luxembourg SA
Original Assignee
Arbed SA
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 Arbed SA filed Critical Arbed SA
Publication of EP0144773A1 publication Critical patent/EP0144773A1/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Withdrawn legal-status Critical Current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
    • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
    • C21C7/04—Removing impurities by adding a treating agent
    • C21C7/064—Dephosphorising; Desulfurising
    • 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
    • C21C1/00—Refining of pig-iron; Cast iron
    • C21C1/02—Dephosphorising or desulfurising
    • 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
    • C21C5/42—Constructional features of converters
    • C21C5/46—Details or accessories
    • C21C5/4606—Lances or injectors
    • C21C5/4613—Refractory coated lances; Immersion lances

Definitions

  • the invention relates to a device for desulfurizing iron and steel melts by introducing desulfurizing agents into the melt.
  • the pig iron or the steel outside the blast furnace or the converter must be desulfurized to produce many steel grades.
  • the liquid iron / steel is consequently filled into metallurgical vessels, and substances are added with the aid of suitable devices, which are able to react at high temperatures and under reducing conditions with the sulfur contained in the melts, which are found in the above remove the slag layer from the melt.
  • suitable devices are, for example, CaSi, CaC 2 , Ca0 or mixtures of Ca0 and CaF2.
  • the apparatus essentially comprehends a storage tank containing desulfurizing agent and under pressure under argon, which is connected via a cellular air blow-through lock to a pressurized argon source and an argon-solid line (hereinafter referred to as the feed line), which leads into a movable diving lance opens.
  • the various lines and the lance practically have a constant cross-section.
  • the cellular wheel blow-through lock has a continuously variable drive.
  • an argon source under high pressure (about 7 bar) is usually used. It is believed that this not only maintains the desired high carrier gas pressure in the lance, but also achieves the required thorough mixing of the desulfurizing agents with the melt by the resulting high speed of the desulfurizing agents.
  • the disadvantage of this procedure is not only that the argon used is expensive, but in particular that the generous amounts of carrier gas have a cooling effect on the melt and that liquid metal is ejected from the pan.
  • there are usually violent vibrations in the lance which result in a shorter service life of the lance body and the suspension device.
  • the invention has for its object to provide a device of the type mentioned, which avoids the disadvantages mentioned above and allows the introduction of desulfurizing agents into the metal melt with minimal amounts of carrier gas.
  • the idea on which the device according to the invention is based is based on the well-known observation that bubbles are formed when air is blown into water through a pipe, for example. If you consider that liquid steel has a surface tension that is 15-20 times greater than that of water, it becomes obvious that the tendency to form bubbles at the mouth of the lance is considerable in desulfurization plants. With such a bubble formation, the gas should periodically be braked strongly, which should result in vibrations in the lance. However, it must now be borne in mind that the gas is loaded with solids, the dynamics of which also play a role.
  • the increase in gas velocity can be achieved either by increasing the pressure of the carrier gas source or by installing a nozzle in the lance mouth. Increasing the source pressure leads to prohibitive argon consumption and was not considered further by the applicant. However, a reduction in the diameter (from 18 to 14 mm) of the lance tube to the last centimeters before the outlet did not lead to a marked reduction in the tendency to blockage or to a decrease in vibrations with the same source pressure.
  • the device described in the introduction must be modified in such a way that either the supply lines or the lance have a cross-sectional constriction extending over a longer distance; here the velocities of the gas and the solids can adapt to each other and the concentration of the solids in the gas, which decreases in a straight tube with increasing gas velocity, remains essentially constant here due to the narrowing of the cross-section. Placing a cross-sectional constriction at the exit or in the vicinity of the rotary valve where the solids only have low speeds would of course lead to blockages. It is therefore appropriate to provide the cross-sectional constriction according to the invention either directly in front of the lance or in the lance itself.
  • the second way cut earlier seems advantageous, since the desired tube profile can be produced from a relatively soft, cheap steel.
  • the profile can often be adapted to any changes in the amount of solid to be conveyed, its grain size, etc.
  • the cross-sectional constriction according to the invention can also be provided in front of the immersion lance.
  • each of the three lances shown is 4 m, the lance protruding lm above the bath level.
  • the jet at the lance mouth must have a pressure that is approximately matched to the surrounding liquid iron.
  • the pressure of the jet at the lance mouth should be about 3.5 bar in the present case.
  • the remaining pressure difference must now be reduced in the profile in such a way that there is no sudden gas acceleration that is unable to entrain the solid body.
  • no such profile is obtained if, for example, the source pressure is too low.
  • the loading factor of the gas is primarily determined by the processes immediately behind the cellular wheel blow-through lock (tendency to clog) and, depending on the design, amounts to 5-25 liters of gas per kg of solids.
  • a coarse grain of the solids increases the tendency to clog near the cell wheel (inertia of the solids) on the one hand, but on the other hand allows a steeper profile narrowing in the immersion lance (larger area of attack of the solids for the accelerating gas).
  • the lance length in m is plotted on the abscissa for the various figures; the ordinate axis shows the lance diameter in mm.
  • the lance shown in Fig. 1 the cross section continuously decreases over the entire length to the lance mouth.
  • Fig. 2 the last two meters before the lance mouth have a constant cross-section. Since the greatest signs of wear occur here with a submersible lance, this embodiment is particularly cost-effective: the lance is produced in two parts, an upper part with a change in cross-section followed by a simple tube of essentially constant cross-section, which is replaced frequently.
  • the lance tube has a slight cross-sectional enlargement towards the lance mouth in order to adapt to the ferrostatic pressure (see FIG. 3).
  • the lance diameter drops from 25 mm at the lance entrance to about 6.7 mm (distance: 1.5 m from the lance end) and then increases again to 8 mm at the lance mouth.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
EP84113394A 1983-11-23 1984-11-07 Dispositif pour désulfurer du fer liquide Withdrawn EP0144773A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19833342198 DE3342198A1 (de) 1983-11-23 1983-11-23 Vorrichtung zum entschwefeln von eisenschmelzen
DE3342198 1983-11-23

Publications (1)

Publication Number Publication Date
EP0144773A1 true EP0144773A1 (fr) 1985-06-19

Family

ID=6214956

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84113394A Withdrawn EP0144773A1 (fr) 1983-11-23 1984-11-07 Dispositif pour désulfurer du fer liquide

Country Status (5)

Country Link
EP (1) EP0144773A1 (fr)
BR (1) BR8403433A (fr)
DE (1) DE3342198A1 (fr)
NO (1) NO844650L (fr)
ZA (1) ZA845557B (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2893716A (en) * 1958-01-14 1959-07-07 Inland Steel Co Gun nozzle for adding lead pellets to liquid steel
FR1228665A (fr) * 1958-07-01 1960-08-31 Centre Nat Rech Metall Procédé de désulfuration de la fonte
DE2528672B1 (de) * 1975-06-27 1976-02-12 Kloeckner Werke Ag Vorrichtung zum foerdern von feinkoernigen feststoffen in metallschmelzen
FR2311614A1 (fr) * 1975-05-21 1976-12-17 Lautjaervi Jaakko Procede et dispositif d'addition de matiere solide, pulverulente ou granulee a un metal fondu
DE3021523A1 (de) * 1980-06-07 1982-05-27 Klöckner Stahltechnik GmbH, 2000 Hamburg Tauchlanze zum einfuehren von feinkoernigem feststoff in eine metallschmelze

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2893716A (en) * 1958-01-14 1959-07-07 Inland Steel Co Gun nozzle for adding lead pellets to liquid steel
FR1228665A (fr) * 1958-07-01 1960-08-31 Centre Nat Rech Metall Procédé de désulfuration de la fonte
FR2311614A1 (fr) * 1975-05-21 1976-12-17 Lautjaervi Jaakko Procede et dispositif d'addition de matiere solide, pulverulente ou granulee a un metal fondu
DE2528672B1 (de) * 1975-06-27 1976-02-12 Kloeckner Werke Ag Vorrichtung zum foerdern von feinkoernigen feststoffen in metallschmelzen
DE3021523A1 (de) * 1980-06-07 1982-05-27 Klöckner Stahltechnik GmbH, 2000 Hamburg Tauchlanze zum einfuehren von feinkoernigem feststoff in eine metallschmelze

Also Published As

Publication number Publication date
DE3342198A1 (de) 1985-05-30
NO844650L (no) 1985-05-24
BR8403433A (pt) 1985-06-25
ZA845557B (en) 1985-03-27

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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Effective date: 19841221

AK Designated contracting states

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17Q First examination report despatched

Effective date: 19860725

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18D Application deemed to be withdrawn

Effective date: 19870205

RIN1 Information on inventor provided before grant (corrected)

Inventor name: BOCK, ANDRE

Inventor name: SCHAAF, ANTOINE

Inventor name: PECKELS, JEAN