EP0015396B1 - Procédé pour l'augmentation de la durabilité des revêtements réfractaires des convertisseurs à garniture basique - Google Patents

Procédé pour l'augmentation de la durabilité des revêtements réfractaires des convertisseurs à garniture basique Download PDF

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Publication number
EP0015396B1
EP0015396B1 EP80100604A EP80100604A EP0015396B1 EP 0015396 B1 EP0015396 B1 EP 0015396B1 EP 80100604 A EP80100604 A EP 80100604A EP 80100604 A EP80100604 A EP 80100604A EP 0015396 B1 EP0015396 B1 EP 0015396B1
Authority
EP
European Patent Office
Prior art keywords
melt
inert gas
slag
vessel
oxygen
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
EP80100604A
Other languages
German (de)
English (en)
Other versions
EP0015396A1 (fr
Inventor
Jerry Vernon Spruell
Jennings Bryan Lewis Iii
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.)
NATIONAL STEEL Corp
Union Carbide Corp
Original Assignee
National Steel Corp
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 National Steel Corp, Union Carbide Corp filed Critical National Steel Corp
Publication of EP0015396A1 publication Critical patent/EP0015396A1/fr
Application granted granted Critical
Publication of EP0015396B1 publication Critical patent/EP0015396B1/fr
Expired 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
    • C21C5/36—Processes yielding slags of special composition
    • 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
    • C21C5/44—Refractory linings
    • C21C5/441—Equipment used for making or repairing linings
    • C21C5/443—Hot fettling; Flame gunning
    • 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
    • C21C5/36—Processes yielding slags of special composition
    • C21C2005/366—Foam slags

Definitions

  • This invention relates to a method for increasing the life of the refractory lining of a basic refractory-lined vessel for the production of steel by blowing oxygen into a ferrous melt from above the surface of the melt, comprising introducing slag-forming ingredients into the vessel, including high-calcium lime and dolomitic lime.
  • dolomitic lime is introduced in an amount which is at least equal to that of the high-calcium lime introduced, and that inert gas is introduced from above the melt surface into the melt in such a manner as to cause intensive interaction between the slag and the melt.
  • inert gas as used throughout the present specification and claims is intended to means a gas other than oxygen having as many as possible of the following characteristics: low reactivity, low specific heat, absence of objectionable contaminants, and high density.
  • the preferred inert gas is argon. However, if nitrogen contamination of the melt is not a problem, nitrogen or air may be used.
  • Other possible inert gases for use in practicing the invention include helium, neon, krypton, xenon, carbon dioxide, steam, ammonia, and mixtures thereof.
  • argon which. may be either commercially pure or crude argon is by far the most preferable inert gas.
  • the preferred method of introducing inert gas is through the oxygen lance admixed with oxygen.
  • the iron charged to a basic oxygen furnace typically contains carbon, silicon, sulfur, and other impurities.
  • the main purpose of the oxygen is to remove carbon and silicon from the melt.
  • the silicon is oxidized to silicon dioxide which floats on the surface of the melt.
  • the carbon is oxidized to carbon monoxide gas which escapes from the mouth of the vessel.
  • Slag forming ingredients typically including high-calcium lime, dolomitic lime, lime stone, and fluorspar, are added to the melt to form a basic slag.
  • the high-calcium lime normally containing at least 90 percent by weight of CaO, also removes sulfur by reacting with it to form calcium sulfide.
  • Dolomitic lime i.e.
  • lime containing at least 30% by weight magnesium oxide is known to improve the life of a vessel's lining, but in addition, it increases the viscosity of the slag, thereby reducing the amount of interaction between the lime in the slag and the melt. The reduced interaction makes it difficult for the lime to remove sulfur from the melt. Since the conventional solution to the problem of obtaining long vessel lining life makes it difficult to make steel having a sufficiently low sulfur content, the amount of dolomitic lime charged to the vessel for conventional oxygen blowing must be limited.
  • dolomitic lime is introduced to the slag in an amount which is at least equal to that of the high-calcium lime introduced.
  • the slag forming compounds should be introduced in an amount sufficient to reduce the sulfur content of the melt to a desired level, based upon the stoichiometric and thermodynamic aspects of the reaction of sulfur with the compounds.
  • dolomitic lime is essential to increasing the life of the vessel's refractory lining.
  • the sulfur content of the steel can be reduced to meet the specification, even if the amount of dolomitic lime is equal to 2 to 3 times the amount of lime introduced.
  • Extra agitation or mixing is required in the vessel because of the increased slag viscosity caused by the larger amount of dolomitic lime.
  • the extra agitation is provided by introducing inert gas into the vessel in such manner as to cause intensive interaction between the slag and the melt.
  • the present invention may be practiced in conjunction with the method disclosed in DE-Al-27 45 722 for using argon in the BOF or make low nitrogen and low oxygen steel.
  • the inert gas must be introduced in such manner as to cause intensive interaction between the slag and the melt.
  • the inert gas is introduced through the oxygen lance by metering it into the oxygen line.
  • the inert gas may be introduced through a separate lance directed to impinge oxygen-free fluid against the surface of the melt.
  • the sulfur content of the melt is one of the most difficult variables to control in the basic oxygen process, occasionally, even when the present invention is practiced the sulfur content of the melt at the end of a blow will be higher than desired.
  • the sulfur content of the melt may be lowered in accordance with a further development of the present invention by adding at least one sulfur-removing compound, such as high-calcium lime, to the slag in the vessel and re-blowing the melt with inert gas alone in such a manner as to cause intensive interaction between the slag and the melt until the sulfur content is reduced to the desired level.
  • at least one sulfur-removing compound such as high-calcium lime
  • the melt with inert gas alone in the above described manner may be used to lower the sulfur content to the desired level.
  • Fig. 1A illustrates a basic oxygen refining vessel together with an oxygen lance through which inert gas likewise is introduced by metering it into the oxygen line.
  • Fig. 1b illustrates a modified embodiment for practicing the method of the invention, wherein the inert gas is introduced through a separate lance.
  • a basic oxygen vessel 1 is provided with a refractory lining 2.
  • a lance 4 is used to inject oxygen and inert gas which is metered into the oxygen line connected to lance 4.
  • the gases are blown into the melt 5 from above the melt surface through lance 4 whereby an emulsion 6 composed of a complex mixture of liquid oxides, gas bubbles, solid oxide particles and droplets of liquid metal is formed.
  • a separate lance 3 is provided in addition to oxygen lance 4.
  • the inert gas is introduced through lance 3 directed to impinge oxygen-free fluid against the surface of melt 5.
  • the normal dolomitic lime charge for this vessel was 7,257 kg.
  • the normal slag-forming ingredients were comprised of 7,257 kg of dolomitic lime and 10,886 kg of high-calcium lime, and 907 kg of flurospar.
  • the dolomitic lime charge was increased to 15,876 kg and the high-calcium lime charge was reduced to 4,536 kg and argon was injected into the vessel in accordance with the method of addition disclosed in DE-Al-27 45 722 mentioned previously.
  • the argon was injected at a constant rate of 99 standard m 3 /min during the latter portion of the oxygen blow.
  • the life of the lining of this vessel was extended from a previous life of about 780 heats to about 1100 heats.
  • dolomitic lime added as slag forming ingredients no difficulty was encountered making steel having sulfur content as low as desired. Furthermore, during this test flurospar, which is known to aid sulfur removal, was not used.
  • Another advantage of the invention is a saving in the amount of flurospar charged to the vessel.
  • the typical maximum sulfur content allowed by the specifications for steel made by this vessel was 0.025% sulfur.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Carbon Steel Or Casting Steel Manufacturing (AREA)
  • Furnace Housings, Linings, Walls, And Ceilings (AREA)

Claims (7)

1. Procédé pour augmenter la longévité du garnissage réfractaire d'une cuve à garnissage réfractaire basique pour la production d'acier par soufflage d'oxygène dans une charge ferreuse fondue à partir du dessus de la surface de la charge fondue, comprenant l'introduction dans la cuve d'ingrédients de formation de laitier comprenant de la chaux à haute teneur en calcium et de la chaux dolomitique, caractérisé en ce que la chaux dolomitique est introduite en une quantité qui est au moins égale à celle de la chaux à haute teneur en calcium introduite, et en ce qu'un gaz inerte est introduit par-dessus la surface de la charge fondue, dans la charge fondue, d'une manière provoquant une interaction intense entre le laitier et la charge fondue.
2. Procédé selon la revendication 1, dans lequel le gaz inerte est introduit par l'intermédiaire de la lance à oxygène.
3. Procédé selon la revendication 1, dans lequel le gaz inerte est introduit par l'intermédiaire d'une lance séparée dirigée de façon à projeter le gaz inerte contre la surface de la charge fondue.
4. Procédé selon l'une quelconque des revendications précédentes, dans lequel la teneur en soufre de la charge fondue est plus élevée que souhaité à la fin du soufflage d'oxygène, comprenant en outre l'étape d'un nouveau soufflage, sur la charge fondue, d'un gaz inerte seul de manière à provoquer une interaction intense entre le laitier et la charge fondue jusqu'à ce que la teneur en soufre soit réduite au niveau souhaité.
5. Procédé selon la revendication 4, dans lequel au moins un composé d'élimination du soufre est ajouté au laitier dans la cuve avant l'étape du nouveau soufflage.
6. Procédé selon l'une quelconque des revendications précédentes, dans lequel la quantité de chaux dolomitique introduite est d'au moins deux fois la quantité de chaux à haute teneur en calcium introduite.
7. Procédé selon l'une quelconque des revendications précédentes, dans lequel le gaz inerte est de l'argon.
EP80100604A 1979-02-07 1980-02-06 Procédé pour l'augmentation de la durabilité des revêtements réfractaires des convertisseurs à garniture basique Expired EP0015396B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US1031579A 1979-02-07 1979-02-07
US10315 1979-02-07

Publications (2)

Publication Number Publication Date
EP0015396A1 EP0015396A1 (fr) 1980-09-17
EP0015396B1 true EP0015396B1 (fr) 1985-05-15

Family

ID=21745183

Family Applications (1)

Application Number Title Priority Date Filing Date
EP80100604A Expired EP0015396B1 (fr) 1979-02-07 1980-02-06 Procédé pour l'augmentation de la durabilité des revêtements réfractaires des convertisseurs à garniture basique

Country Status (14)

Country Link
EP (1) EP0015396B1 (fr)
JP (1) JPS5952201B2 (fr)
AU (1) AU5526080A (fr)
BR (1) BR8000733A (fr)
CA (1) CA1143947A (fr)
DE (1) DE3070636D1 (fr)
ES (1) ES488303A0 (fr)
FI (1) FI800335A (fr)
IN (1) IN153626B (fr)
MX (1) MX154163A (fr)
NO (1) NO800301L (fr)
PH (1) PH15430A (fr)
RO (1) RO79757A (fr)
ZA (1) ZA80213B (fr)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2525633A1 (fr) * 1982-04-22 1983-10-28 Siderurgie Fse Inst Rech Procede pour ameliorer la duree de vie d'elements refractaires permeables loges dans le fond des recipients metallurgiques d'affinage, notamment des convertisseurs d'acierie a soufflage d'oxygene par le haut
AT385771B (de) * 1986-06-16 1988-05-10 Voest Alpine Ag Verfahren zum ueberziehen der feuerfesten auskleidung eines metallurgischen schmelzofens mit einem hitzebestaendigen material
DE3936715A1 (de) * 1989-11-03 1991-05-08 Kortec Ag Verfahren zum einbringen von fliessfaehigen zuschlagsstoffen in ein metallurgisches gefaess und gefaess fuer dieses verfahren
CN1035017C (zh) * 1994-04-21 1997-05-28 鞍山钢铁公司 炼钢中用轻烧镁球团造渣法
GB2553342A (en) * 2016-09-02 2018-03-07 Materials Proc Institute Producing steel

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3288592A (en) * 1963-01-16 1966-11-29 Pfizer & Co C Process for reducing deterioration in equipment handling molten materials
FR1346148A (fr) * 1963-01-31 1963-12-13 Centre Nat Rech Metall Procédé pour la protection du revêtement intérieur des fours métallurgiques
FR1536457A (fr) * 1967-07-07 1968-08-16 Siderurgie Fse Inst Rech Procédé pour la protection des revêtements réfractaires des récipients métallurgiques d'affinage continu
US3726665A (en) * 1969-10-15 1973-04-10 C & W Corson H Inc Slagging in basic steel-making process
US3915696A (en) * 1970-01-08 1975-10-28 Ferdinand Fink Sintered preformed slag for the steel industry
BR7302595D0 (pt) * 1972-05-09 1974-06-27 Blanq Cazaux Morales A Aperfeicoamentos em processo para fabricacao de ferro e acaperfeicoamentos em processo para fabricacao de ferro e acos os
FR2322202A1 (fr) * 1975-08-29 1977-03-25 Siderurgie Fse Inst Rech Procede d'elaboration d'acier par soufflage d'oxygene
ZA775918B (en) * 1977-01-11 1978-05-30 Nat Steel Corp The use of orgon to prepare low-carbon,low-nitrogen steels in the basic oxygen process
JPS545813A (en) * 1977-06-17 1979-01-17 Fuaizaa Kuiguree Kk Method of extending useful life of refractory lining material in aod furnace

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Stahl und Eisen 96 (1976), pages 878/879 *

Also Published As

Publication number Publication date
IN153626B (fr) 1984-07-28
ES8100349A1 (es) 1980-11-01
EP0015396A1 (fr) 1980-09-17
DE3070636D1 (en) 1985-06-20
AU5526080A (en) 1980-08-14
MX154163A (es) 1987-05-28
ZA80213B (en) 1980-12-31
PH15430A (en) 1983-01-18
RO79757A (fr) 1983-02-01
FI800335A (fi) 1980-08-08
NO800301L (no) 1980-08-08
ES488303A0 (es) 1980-11-01
JPS55107714A (en) 1980-08-19
BR8000733A (pt) 1980-10-21
JPS5952201B2 (ja) 1984-12-18
CA1143947A (fr) 1983-04-05

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