EP0050743A1 - Verfahren zur Erzeugung von Stahl im basischen Konverter unter Verwendung von flüssiger Konverterschlacke - Google Patents

Verfahren zur Erzeugung von Stahl im basischen Konverter unter Verwendung von flüssiger Konverterschlacke Download PDF

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Publication number
EP0050743A1
EP0050743A1 EP81107683A EP81107683A EP0050743A1 EP 0050743 A1 EP0050743 A1 EP 0050743A1 EP 81107683 A EP81107683 A EP 81107683A EP 81107683 A EP81107683 A EP 81107683A EP 0050743 A1 EP0050743 A1 EP 0050743A1
Authority
EP
European Patent Office
Prior art keywords
slag
steel
converter
amount
blowing
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.)
Pending
Application number
EP81107683A
Other languages
German (de)
English (en)
French (fr)
Inventor
Gustav Dr.-Ing. Mahn
Dieter Dr.-Ing. Nolle
Ulrich Dipl.-Ing. Eulenburg
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.)
Stahlwerke Pein Salzgitter AG
Preussag Stahl AG
Original Assignee
Stahlwerke Pein Salzgitter AG
Preussag Stahl 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 Stahlwerke Pein Salzgitter AG, Preussag Stahl AG filed Critical Stahlwerke Pein Salzgitter AG
Publication of EP0050743A1 publication Critical patent/EP0050743A1/de
Pending 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
    • C21C5/42—Constructional features of converters
    • C21C5/44—Refractory linings
    • 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
    • C21C5/36—Processes yielding slags of special composition
    • C21C2005/366—Foam slags

Definitions

  • the present invention relates to a method for producing steel in a basic converter using liquid converter slag.
  • Efforts to increase shelf life must therefore be directed towards increasing the slag basicity, especially in the early stages of freshening.
  • a chemical-metallurgical attack of the slag on the refractory, basic converter lining can only be achieved by saturating the slag with MgO, Ca0 or Dicalcium silicate can be reduced during the entire fresh process.
  • the composition of the final slag alone cannot be used as a criterion for the wear of the refractory material.
  • saturation of the initial slag with Mg0 or CaO has so far encountered great difficulties because the Mg0 or Ca0 introduced does not dissolve sufficiently quickly. Solubility only improves during the fresh process.
  • DE-OS 28 52 248 has achieved the following in DE-OS 28 52 248:
  • the Mg0 or the MgO-containing substances are blown into the focal spot area in the presence of CaO or Ca0-containing basic substances. Exactly certain amounts of aggregates in certain grain sizes are used for this. Then the required amount of remaining lime is added.
  • This process leads to a rapid dissolution of the additives due to the high temperature in the focal spot area.
  • the high MgO contents required to protect the converter lining are only achieved after a reaction time, albeit a short one.
  • After about 20% of the fresh time there is an MgO-saturated slag.
  • a blowing lance which is suitable for blowing in solids, is required to blow in the additives.
  • the initial slag is not yet saturated with MgO using this process.
  • the basicity of the initial slag is also as low as is known from the classic LD process.
  • the increase in the basicity of the initial slag and thus the reduction in the Mg0 and CaO contents leading to saturation can be achieved by using substances with a high basicity and low melting point, e.g. Converter slag can be reached before or at the start of freshness.
  • converter slag is known and e.g. published in patent specification FR-PS 15 09 342.
  • This is a special variant of the LDAC process, in which the final slag always remains in the converter and is slagged off after about 50% of the blowing time.
  • the object of the present invention is to greatly increase the basicity of the initial slag and to keep the slag as possible over the entire fresh process, but at least in the critical initial area at the saturation limit. Since the invention is intended to apply to all basic brickwork, that is to say for magnesite and dolomitic infeed, in addition to the MgO saturation the saturation of the slag on Ca0 or on dicalcium silicate can also be achieved. In the known and cited prior art, compliance with the double saturation of 2 CaO. SiO 2 and at the same time at Mg0 were not achieved over the entire fresh process and also not during the critical initial phase.
  • the slag contains 2 CaO during the entire fresh process. SiO 2 saturated.
  • the MgO levels approach the saturation limit. This procedure is characterized by better solubility of the slag for the added additives because the temperature rises steeply during the fresh process in the absence of the scrap (Fig. 7).
  • the higher temperature range at Blasbeginn promotes the dissolution of the dolomite used and lime.
  • the FeO content of the slag at the start of blowing is very low when sampling after 30% of the blowing time.
  • the FeO contents are well over 20% and, in combination with the acidic slags, lead to a strong fire-resistant attack.
  • the Fe0 contents can be reduced to 5%.
  • the amount of MgO required to saturate the slag is blown in together with a fresh agent in fine-grained form from the beginning of the blowing up to about 25 to 30% of the blowing time.
  • the amount of slag used at the beginning of the blow is as shown in the slag amount diagram a in Figure 1 and which corresponds to approximately twice the amount at the end of the blow compared to the known LD process without the use of slag ( Figure 1).
  • the amount of Mg0 added according to the invention is set according to a nomogram to determine the amount of Mg0 added ( Figure 2) as a function of the silicon content of the pig iron at the start of blowing.
  • the combination according to the invention of the slag from the previous melt remaining in the converter and the use of the additives dolomite, lime and scrap before or at the beginning of the fresh phase resulted in a completely new, unexpected slag flow.
  • the decisive factor was the finding that the melts could be blown without ejection.
  • the advantages of this procedure can be considered in several ways.
  • the durability of the converter lining is determined by setting the double saturation at 2 Ca0. Si0 2 and Mg0 significantly improved during the entire bubble period or at least during the critical initial phase.
  • the amount of additives to saturate the slag with Mg0 could be considerably reduced by the retention of the liquid converter slag. The slag guidance is substantially evened out.
  • the double saturated slag at 2 CaO. SiO 2 and Mg0 is heterogeneous and forms a protective coating on the converter lining.
  • Mg0 is preferably saturated with mervinite, monticellite and magnesiowustite; in the initial slags primarily via mervinite and monticellite and in the final slags only via magnesiowustite.
  • the delayed use of scrap compared to the classic LD process continues to favor the dissolution conditions of the dolomite or lime used due to the higher initial temperatures of the process.
  • the sulfur distribution between metal and slag was significantly improved and much better final sulfur contents could be achieved.
  • the dephosphorization is also improved compared to the normal LD process.
  • Figure 3 gives an overview of the influence of the residual slag remaining in the converter on the basicity of the slag (expressed by the ratio during the fresh process.
  • the second, middle course of the curve contains the basicity values which have become known from the literature through the reuse of partial quantities of slag, here about 5 t with a 200 t converter (25 kg slag per t steel). An influence on the basicity of the initial slag can already be seen here.
  • the slag composition during the blowing process is described in more detail by Figure 4, by the representation of the course of the slag composition in the three-component system (Ca0 + Mn0 + MgO) '- Fe0' - Si0 2 '. While the slag passes through the unsaturated area of FeO and SiO 2 rich slags at the start of blowing in the normal LD process, this area is no longer touched when working with a higher basicity and simultaneous use of Mg0 and the slag is reached or remains in during the entire melt duration Area of the 2 CaO. SiO 2 saturation (- 5% MnO and -10% MgO).
  • the slags move from the final slag towards the 2 CaO. SiO 2 compound and return to the final slag.
  • substantially lower FeO contents in the slag are set over the entire blowing process.
  • the change in the slag composition during the blowing process is therefore considerably less than in the normal LD process and proceeds in the area of more basic, more iron-oxidized slags, which result in significantly less converter wear.
  • the saturation of the slag on Mg0 is described in Figure 5. While in the normal LD process the acidic slags have to dissolve 15 to 20% Mg0 in order to achieve MgO saturation, the process according to the invention, when working with high basicity, is based on that in the converter remaining slag, only a MgO content of 8 to 10% in the initial slags.
  • the most suitable magnesite carrier is dolomite. The time of use is before or at the start of blowing.
  • MgO contents and the contents of dissolved Mg0 (MgO s ) during the blowing time can be found in Figure 6.
  • the MgO contents with different procedures differ, they start from the same contents and end at the same stopped. While the MgO saturation of the slag is achieved over the entire melting time according to the method of claim 3, only the initial and final slags of Mg0 are saturated in a procedure according to claims 1 and 2.
  • Example 1 is intended to illustrate the process according to claim 1.
  • the residual slag must first be formed.
  • an LD melt is produced in a 200 t converter using the usual method.
  • the dolomite is also set before the start of blowing.
  • the required amount of Mg0 can be found in the nomogram in Figure 2.
  • Example 2 describes the operating conditions according to claim 2.
  • the formation of the residual slag takes place as already described in claim 1.
  • the lime and then the dolomite are set.
  • the respective quantities are calculated as follows:
  • the amount of MgO Due to the silicon content of the pig iron, the amount of MgO (according to Figure 2) is 7.2 kg / t steel; this corresponds to 1,400 kg MgO for a 200 t melt. With a content of 37% Mg0 in the dolomite, the amount of dolomite to be used is 3890 kg. The CaO content in dolomite is 58%, that is 2256 kg Ca0 and with 92% Ca0 in lime this results in a lime quantity of 2450 kg. Based on the pig iron analysis, the lime scale is 10.16 t, from which 2.45 t have to be deducted, so that the amount of lime to be used is 7.71 t.
  • the slag is saturated with Mg0 up to 20% and from 80% blowing time with this mode of operation.
  • Example 3 illustrates the process according to claim 3.
  • the residual slag is initially formed here as described in Example 1.
  • the converter then contains 22 t of slag.
  • Part of the lime is placed in the thorn.
  • the amount of lime and dolomite is calculated according to the following scheme.
  • the necessary amount of MgO can be taken from the nomogram ( Figure 2) with 7.5 kg / t steel, which corresponds to a 200 t Melt 1500 kg MgO. With a share of 37% MgO in the dolomite, the amount of dolomite is 4050 kg. The Ca0 content of the dolomite is (at 58%) 2350 kg, corresponding to 2550 kg of lime. Based on the pig iron analysis, the lime scale is 10.45 t; this leaves 2.55 t so that a quantity of 7.9 t lime remains; of this amount, 2.5 tons of lime are used. Then the calculated quantity of 4.05 t of dolomite is set. Then the fresh process begins.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Carbon Steel Or Casting Steel Manufacturing (AREA)
EP81107683A 1980-10-29 1981-09-28 Verfahren zur Erzeugung von Stahl im basischen Konverter unter Verwendung von flüssiger Konverterschlacke Pending EP0050743A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3040630 1980-10-29
DE3040630A DE3040630C2 (de) 1980-10-29 1980-10-29 Verfahren zur Erzeugung von Stahl im basischen Konverter unter Verwendung von flüssiger Konverterschlacke

Publications (1)

Publication Number Publication Date
EP0050743A1 true EP0050743A1 (de) 1982-05-05

Family

ID=6115389

Family Applications (2)

Application Number Title Priority Date Filing Date
EP81107683A Pending EP0050743A1 (de) 1980-10-29 1981-09-28 Verfahren zur Erzeugung von Stahl im basischen Konverter unter Verwendung von flüssiger Konverterschlacke
EP81902685A Expired EP0063569B1 (de) 1980-10-29 1981-09-28 Verfahren zur erzeugung von stahl im basischen konverter unter verwendung von flüssiger konverterschalcke

Family Applications After (1)

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EP81902685A Expired EP0063569B1 (de) 1980-10-29 1981-09-28 Verfahren zur erzeugung von stahl im basischen konverter unter verwendung von flüssiger konverterschalcke

Country Status (5)

Country Link
US (1) US4421554A (enExample)
EP (2) EP0050743A1 (enExample)
JP (1) JPH0259201B2 (enExample)
DE (1) DE3040630C2 (enExample)
WO (1) WO1982001565A1 (enExample)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3219409C2 (de) * 1982-05-19 1984-10-11 Schweizerische Aluminium Ag, Chippis Verfahren zur Bestimmung der Oxidationsgeschwindigkeit an der Oberfläche einer Metallschmelze
US5567222A (en) * 1994-03-24 1996-10-22 Kawasaki Steel Corporation Method of controlling slag coating of a steel converter
DE4433511C2 (de) * 1994-09-20 1998-02-05 Klaus Juergen Hanke Verfahren zur Erzeugung von Stahl
US6082358A (en) 1998-05-05 2000-07-04 1263152 Ontario Inc. Indicating device for aerosol container
US6401329B1 (en) 1999-12-21 2002-06-11 Vishay Dale Electronics, Inc. Method for making overlay surface mount resistor
CN102212641A (zh) * 2011-06-15 2011-10-12 南京钢铁股份有限公司 一种快速成渣的方法
RU2545874C2 (ru) * 2012-04-27 2015-04-10 Закрытое Акционерное Общество "МагнийПром" Способ получения магнезиального флюса для выплавки стали
CN104673966A (zh) * 2015-01-22 2015-06-03 河北钢铁股份有限公司承德分公司 转炉炉衬的快速维护方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1346148A (fr) * 1963-01-31 1963-12-13 Centre Nat Rech Metall Procédé pour la protection du revêtement intérieur des fours métallurgiques
DE2852248A1 (de) * 1978-12-02 1980-06-04 Dolomitwerke Gmbh Verfahren zur erhoehung der haltbarkeit basischer ausmauerungen von konvertern beim frischen von phosphorarmem roheisen

Family Cites Families (7)

* 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
LU50247A1 (enExample) * 1966-01-12 1967-07-12
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
US3507642A (en) * 1969-06-02 1970-04-21 Allegheny Ludlum Steel Process for producing corrosion resistant steel
US3897244A (en) * 1973-06-08 1975-07-29 Crawford Brown Murton Method for refining iron-base metal
US3884678A (en) * 1974-02-04 1975-05-20 Jones & Laughlin Steel Corp Fluxes
FR2271293B1 (enExample) * 1974-05-15 1977-06-24 Lafarge Fondu Int

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1346148A (fr) * 1963-01-31 1963-12-13 Centre Nat Rech Metall Procédé pour la protection du revêtement intérieur des fours métallurgiques
DE2852248A1 (de) * 1978-12-02 1980-06-04 Dolomitwerke Gmbh Verfahren zur erhoehung der haltbarkeit basischer ausmauerungen von konvertern beim frischen von phosphorarmem roheisen

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
Stahl und Eisen, Band 100, Nr. 20, 6. Oktober 1980, Dusseldorf (DE) K-H. OBST et al.: Uber das Auflosungsverhalten von Magnesiumoxid in der Schlacke beim LD-Verfahren", seiten 1194- 1201 * seite 1195, spalte 2, absatz 3; seite 1197, spalte 1, absatze 2 und 3; spalte 2, absatze 1 und 3; seite 1200, spalten 1 und 2 * *
Steel in the USSR, Band 2, Nr. 8, August 1972, A.F. KUZNETSOV et al.: "Accelerating Slag Formation when melting Steel in Basic Oxygen Furnaces", seiten 608-611 * seite 608, Zusammenfassung * *
Steel in the USSR, Band 3, Nr. 8, August 1973, V.I. BAPTIZMANSKII et al.: "Improving Slag Formation in Basic Oxygen Furnaces", seiten 634-638 * seite 637, spalte 2, Punkt 4; seite 638, spalte 1, Punkt 9(ii)* *

Also Published As

Publication number Publication date
EP0063569B1 (de) 1986-01-08
DE3040630A1 (de) 1982-04-29
DE3040630C2 (de) 1983-03-31
JPH0259201B2 (enExample) 1990-12-11
JPS57501863A (enExample) 1982-10-21
US4421554A (en) 1983-12-20
WO1982001565A1 (en) 1982-05-13
EP0063569A1 (de) 1982-11-03

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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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Free format text: VERFAHREN ABGESCHLOSSEN INFOLGE VERBINDUNG MIT 81902685.7/0063569 (EUROPAEISCHE ANMELDENUMMER/VEROEFFENTLICHUNGSNUMMER) VOM 25.07.84.

RIN1 Information on inventor provided before grant (corrected)

Inventor name: MAHN, GUSTAV, DR.-ING.

Inventor name: NOLLE, DIETER, DR.-ING.

Inventor name: EULENBURG, ULRICH, DIPL.-ING.