EP0063569B1 - Procede de production d'acier en convertisseur basique avec utilisation de latier - Google Patents

Procede de production d'acier en convertisseur basique avec utilisation de latier Download PDF

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Publication number
EP0063569B1
EP0063569B1 EP81902685A EP81902685A EP0063569B1 EP 0063569 B1 EP0063569 B1 EP 0063569B1 EP 81902685 A EP81902685 A EP 81902685A EP 81902685 A EP81902685 A EP 81902685A EP 0063569 B1 EP0063569 B1 EP 0063569B1
Authority
EP
European Patent Office
Prior art keywords
slag
mgo
cao
steel
converter
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
EP81902685A
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German (de)
English (en)
Other versions
EP0063569A1 (fr
Inventor
Gustav Mahn
Dieter Nolle
Ulrich 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 EP0063569A1 publication Critical patent/EP0063569A1/fr
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Publication of EP0063569B1 publication Critical patent/EP0063569B1/fr
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    • 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, in which an end slag saturated with MgO and CaO or dicalcium silicate is obtained.
  • low-viscosity low-basicity iron oxide-silicate slags behave aggressively towards the basic brick lining, they infiltrate into the stone pores during the blowing process and react there with the CaO of the dolomite. In addition, this slag has a considerable solvency for MgO. This solubility of the slag is greatest at the beginning of the freshening process and decreases at the end of the blowing with increasing basicity. The slag attack on the converter lining is the greatest at the beginning of the fresh season.
  • 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 MgO 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 has been published, for example, in patent specification FR-PS 1 509 342.
  • This is a special variant of the LDAC process, in which the final slag always remains in the converter and is slagged 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 region at the saturation limit. Since the invention is intended to apply to all basic brickwork, that is to say to magnesitic and dolomitic infeed, in addition to the MgO saturation, the slag must also be saturated with CaO or with dicalcium silicate. In the known and cited prior art, compliance with the double saturation of 2 Ca0-Si0 2 and at the same time of MgO has not been achieved over the entire fresh process and also not during the critical initial phase.
  • the temperature fluctuates around 1525 ° C when the scrap is used, it can oscillate between 1500 and 1550 ° C and increases to around 1625 ° C at the end of the fresh process.
  • the higher temperature range at the start of blowing promotes the dissolution of the dolomite and lime used.
  • 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 FeO 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. Furthermore, the amount of MgO required for the saturation of the slag can be introduced in the form of dolomite, the amount of CaO introduced via the dolomite being taken into account when adding CaO.
  • a quantity of slag is used at the beginning of the blow, as can be seen from the slag quantity 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 using slag ( Figure 1).
  • the amount of MgO added is set according to a nomogram to determine the amount of MgO added ( Figure 2) as a function of the silicon content of the pig iron at the start of blowing.
  • so much CaO is added that the slag is saturated with CaO or dicalcium silicate.
  • the slag guidance is substantially evened out.
  • the double saturated slag of 2 CaO ⁇ SiO 2 and MgO is heterogeneous and forms a protective coating on the converter lining.
  • MgO 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 dissolving conditions of the dolomite or lime used due to the higher initial temperatures of the process.
  • it was found that the sulfur distribution between metal and slag was significantly improved and that much better final sulfur contents could be achieved.
  • the dephosphorization is also improved compared to the normal LD process.
  • 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-substance system (CaO + MnO + MgO) '- FeO'-SiO 2 . While the slag passes through the unsaturated area of FeO- and Si0 2 -rich slag at the start of blowing in the normal LD process, this area is no longer touched when working with higher basicity and simultaneous use of Mg0 and the slag is reached or remains in the entire melting time Area of 2 CaO.Si02 saturation (-5% MnO and -10% MgO).
  • the slags move from the final slag towards the 2 CaO. Si0 2 connection and return to the final slag.
  • substantially lower FeO contents are set in the slag over the entire blowing process.
  • the change in the slag composition during the blowing process is therefore much less than in the normal LD process and takes place in the area of more basic, more iron-oxidized slags, which result in significantly less converter wear.
  • the saturation of the slag with MgO is described in Fig. 5. While in the normal LD process the acidic slags have to dissolve 15 to 20% MgO to achieve the MgO saturation, in the process according to the invention, when working with high basicity, the slag remaining in the converter to only set an MgO content of 8 to 10% in the starting slag. Dolomite is most suitably used as the magnesite carrier. The time of use is before or at the start of blowing.
  • MgO contents and the contents of dissolved MgO (MgOg) 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 contents. While the MgO saturation of the slag is achieved over the entire melting time by the method according to claim 3, only the initial and final slags of MgO are saturated in a procedure according to claims 1 and 2.
  • Example 1 is intended to illustrate the process according to claim 1.
  • the final slag has to 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 MgO can be found in the nomogram in Figure 2.
  • the slag is saturated with MgO in this mode of operation up to 20% and from 80% blowing time.
  • Example 3 illustrates the process according to claim 3.
  • the formation of the final slag takes place here first as described in Example 1.
  • the converter then contains 22 t of slag.
  • part of the lime is placed.
  • 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 1500 kg MgO for a 200 t melt. With a share of 37% MgO in the dolomite, the amount of dolomite is 4050 kg. The CaO portion of the dolomite is (at 58%) 2350 kg, corresponding to 2550 kg of lime. The lime scale is 10.45t based on the pig iron analysis; 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. The calculated quantity of 4.05 t of dolomite is then set. Then the fresh process begins.
  • the slag is saturated with MgO from the beginning of the blowing to the end of the blowing.

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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)

Claims (6)

1. Procédé pour la production d'acier en convertisseur basique avec utilisation d'un laitier liquide de convertisseur, dans lequel est produit un laitier final saturé en MgO et CaO ou en silicate bicalcique, caractérisé en ce que:
- on laisse le laitier final de la charge précédente dans le convertisseur après la fin du soufflage et la coulée de l'acier,
- on ajoute à ce laitier, avant ou au début du soufflage, une quantité de 5,0 à 9,5 kg de MgO par tonne d'acier, en fonction de la teneur en Si de la fonte, suivant le nomogramme pour la détermination de l'addition de MgO (b) (fig.2) en même temps que les fondants de formation du laitier,
- on réalise ensuite le chargement de la fonte,
- on introduit ensuite les ferrailles,
- on ajoute alors suffisament de CaO pour at- teindre la saturation du laitier en CaO ou en silicate bicalcique,
- on dispose à la fin du soufflage, en fonction de la teneur de 0,4 à 1,0% en Si dans la fonte, d'une quantité de laitier d'environ 120 à environ 390 kg par tonne d'acier suivant le diagramme pondéral du laitier (a) (fig. 1),
- on soutire, après la fin du soufflage, la moitié du laitier, la quantité de laitier restant dans le convertisseur étant utilisée pour la charge suivante.
2. Procédé pour la production d'acier en convertisseur basique avec utilisation d'un laitier liquide de convertisseur, dans lequel il se produit un laitier final saturé en MgO et CaO ou en silicate bicalcique, caractérisé en ce que:
- on laisse le laitier final de la charge précédente dans le convertisseur après la fin du soufflage et la coulée de l'acier,
- on ajoute à ce laitier, avant ou au début du soufflage, une quantité de 5,0 à 9,5 kg de MgO par tonne d'acier, en fonction de la teneur en Si de la fonte, suivant le nomogramme pour la détermination de l'addition de MgO (b) (fig.2) en même temps que les fondants de formation du laitier,
- on réalise ensuite le chargement de la fonte,
- on ajoute alors suffisamment de CaO pour at- teindre la saturation du laitier en CaO ou en silicate bicalcique,
- on ajoute les ferrailles après environ 25 à 30% de la durée du soufflage,
- on dispose à la fin du soufflage, en fonction de la teneur de 0,4 à 1,0% en Si dans la fonte, d'une quantité de laitier d'environ 120 à environ 390 kg par tonne d'acier suivant le diagramme pondéral du laitier (a) (fig. 1),
- on soutire après la fin du soufflage, la moitié du laitier, la quantité du laitier restant dans le convertisseur étant utilisée pour la charge suivante.
3. Procédé selon la revendication 2, caractérisé en ce que lors de l'addition de la quantité de CaO, on n'introduit qu'environ 20 à 50% de la quantité de CaO nécessaire, la quantité restante de CaO nécessaire étant ajoutée, après environ 25 à 30% de la durée de soufflage, en même temps que les ferrailles.
4. Procédé selon les revendications 1, 2 et 3, caractérisé en ce qu'on diminue la quantité de CaO nécessaire de la quantité de MgO établie d'après le nomogramme (b).
5. Procédé selon les revendications 1, 2 et 3, caractérisé en ce qu'on introduit par soufflage la quantité de MgO nécessaire à la saturation du laitier, sous une forme finement granulée depuis le début jusqu'à environ 25 à 30% de la durée du soufflage, en même temps qu'un agent d'affinage.
6. Procédé selon les revendications 1, 2 et 3, caractérisé en ce qu'on introduit la quantité de MgO nécessaire à la saturation du laitier sous la forme de dolomite, la quantité de CaO introduite par l'intermédiaire de la dolomite étant prise en compte lors de l'addition du CaO.
EP81902685A 1980-10-29 1981-09-28 Procede de production d'acier en convertisseur basique avec utilisation de latier Expired EP0063569B1 (fr)

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 (2)

Publication Number Publication Date
EP0063569A1 EP0063569A1 (fr) 1982-11-03
EP0063569B1 true EP0063569B1 (fr) 1986-01-08

Family

ID=6115389

Family Applications (2)

Application Number Title Priority Date Filing Date
EP81107683A Pending EP0050743A1 (fr) 1980-10-29 1981-09-28 Procédé de fabrication d'acier au convertisseur basique avec utilisation de laitier de convertisseur liquide
EP81902685A Expired EP0063569B1 (fr) 1980-10-29 1981-09-28 Procede de production d'acier en convertisseur basique avec utilisation de latier

Family Applications Before (1)

Application Number Title Priority Date Filing Date
EP81107683A Pending EP0050743A1 (fr) 1980-10-29 1981-09-28 Procédé de fabrication d'acier au convertisseur basique avec utilisation de laitier de convertisseur liquide

Country Status (5)

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

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6953039B2 (en) 1998-05-05 2005-10-11 Trudell Medical International Medicament dispensing device

Families Citing this family (7)

* 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
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

Family Cites Families (9)

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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
LU50247A1 (fr) * 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 (fr) * 1974-05-15 1977-06-24 Lafarge Fondu Int
DE2852248C3 (de) * 1978-12-02 1982-02-11 Dolomitwerke GmbH, 5603 Wülfrath Verfahren zur Erhöhung der Haltbarkeit basischer Ausmauerungen von Konvertern beim Frischen von Roheisen

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6953039B2 (en) 1998-05-05 2005-10-11 Trudell Medical International Medicament dispensing device

Also Published As

Publication number Publication date
WO1982001565A1 (fr) 1982-05-13
JPS57501863A (fr) 1982-10-21
JPH0259201B2 (fr) 1990-12-11
DE3040630A1 (de) 1982-04-29
DE3040630C2 (de) 1983-03-31
EP0063569A1 (fr) 1982-11-03
EP0050743A1 (fr) 1982-05-05
US4421554A (en) 1983-12-20

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