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EP0063569A1 - 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.

Info

Publication number
EP0063569A1
EP0063569A1 EP81902685A EP81902685A EP0063569A1 EP 0063569 A1 EP0063569 A1 EP 0063569A1 EP 81902685 A EP81902685 A EP 81902685A EP 81902685 A EP81902685 A EP 81902685A EP 0063569 A1 EP0063569 A1 EP 0063569A1
Authority
EP
European Patent Office
Prior art keywords
slag
mgo
steel
blowing
amount
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.)
Granted
Application number
EP81902685A
Other languages
German (de)
English (en)
Other versions
EP0063569B1 (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
Original Assignee
Stahlwerke Pein Salzgitter 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 filed Critical Stahlwerke Pein Salzgitter AG
Publication of EP0063569A1 publication Critical patent/EP0063569A1/fr
Application granted granted Critical
Publication of EP0063569B1 publication Critical patent/EP0063569B1/fr
Expired legal-status Critical Current

Links

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.
  • DE-OS 28 52248 has achieved the following in DE-OS 28 52248:
  • the MgO or the MgO-containing substances are blown into the focal spot area in the presence of CaO or CaO-containing basic substances. Exactly certain amounts of aggregates in certain grain sizes are used for this. The required amount of remaining lime is then 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 blow is required that is suitable for blowing in solids.
  • the initial slag is not yet saturated with MgO by this process.
  • zesses As is known, chemical wear depends on the composition of the slag during the refining process. According to the current state of knowledge, a high iron oxide content has a negative effect, especially at the prevailing high temperatures, since a reaction takes place between the iron oxide and the carbon of the refractory delivery binder, which is decarburized in the first phase of wear. It is also known that increasing silicon contents reduce the life of the basic refractory materials. But especially in the first minutes of the freshening process, due to the silicon content of the pig iron and the corresponding iron oxide, high silicon oxide concentrations and an acidic slag form, since the lime used cannot dissolve so quickly.
  • low-viscosity low-basicity iron oxide-silicate slags are aggressive 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 therefore greatest at the beginning of the fresh season.
  • converter slag is known and e.g. published in patent specification FR-PS 1509342.
  • 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 for magnesite and dolomitic infeed, in addition to the MgO saturation the slag is also saturated with CaO or dicalcium silicate. In the known and cited state of the
  • 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 temperature fluctuates around 1525 ° C at the start of scrap, it can fluctuate 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 refractory 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.
  • a quantity of slag is used at the start of the blowing process, as can be seen from the slag quantity diagram a in Figure 1 and which at the end of the blowing corresponds to approximately twice the amount compared to the known LD process without the use of slag ( Figure 1).
  • the amount of MgO added is set according to a nomogram for determining the MgO addition b ( Figure 2) as a function of the silicon content of the pig iron at the start of blowing.
  • the slag guidance is substantially evened out.
  • 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 beginning it was primarily about mervinite and monticellite and in the final slag it was only about 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.
  • Representing the normal LD process is the course of the basicity according to Ijmuiden, according to the designation DE-AS 2427205 "Process for the preparation of iron-based metal", Applicant: Murton, Crawford, B., Pittsburgh, Pa. (USA) and according to the results for normal initial slags at Stahltechnike Peine-Salzgitter AG (P + S).
  • 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 in 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 passes through the unsaturated area of FeO and SiO 2 rich slags at the start of blowing, this area is touched more when working with higher basicity and simultaneous use of MgO and the slag is reached or is in the area during the entire melting period 2 CaO. SiO 2 saturation (- 5% MnO and -10% MgO).
  • the slags move from the end slugs in the direction of 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 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 due to the remaining in the converter Slag, only a MgO content of 8 to 10% should be set in the initial slags.
  • the most suitable magnesite carrier is dolomite. The time of use is before or at the start of blowing.
  • MgO saturation of the slag is achieved over the entire melting time, 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 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 MgO 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 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% MgO in the dolomite, the amount of dolomite to be used is 3890 kg. The CaO content in dolomite is 58%, that is 2256 kg CaO and with 92% CaO in lime this results in a lime quantity of 2450 kg. Based on the pig iron analysis, the K ⁇ lksatz 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 MgO in this mode of operation up to 20% and from 80% blowing time.
  • 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.
  • a part of the lime is placed there.
  • the calculation of the amount of lime and dolomite follows the following scheme.
  • 7.5 kg / t of steel can be extracted, which corresponds to a 200 t Melt 1500 kg MgO.
  • 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 10.45 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.
  • the slag is saturated with MgO from the beginning of the blow to the end of the blow.

Landscapes

  • 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)

Abstract

Avec le present procede, on augmente considerablement la basicite du laitier de depart et on maintient le laitier a la limite de saturation, si possible pendant tout l'affinage, mais au moins pendant la periode de demarrage critique. Il convient d'atteindre la saturation en MgO et aussi la saturation du laitier en CaO et en disilicate de calcium. Vers la fin du soufflage, on travaille avec une quantite de scories fixe par tonne d'acier pour une teneur en Si determinee dans la fonte brute. On ajoute a la fonte de depart, avant ou pendant le debut de l'affinage, avec les fondants pour la scorification, une certaine quantite de MgO par tonne d'acier en fonction de la teneur en Si de la fonte; apres le debut d'affinage et apres la piquee de l'acier, la totalite du laitier reste dans le convertisseur. Ceci a l'avantage que, d'une part, la duree de la chemise du four est augmentee et, d'autre part, la quantite des fondants necessaires est considerablement reduite. Le reglage du laitier est plus regulier et les resultats metallurgiques sont ameliores.
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 true EP0063569A1 (fr) 1982-11-03
EP0063569B1 EP0063569B1 (fr) 1986-01-08

Family

ID=6115389

Family Applications (2)

Application Number Title Priority Date Filing Date
EP81902685A Expired EP0063569B1 (fr) 1980-10-29 1981-09-28 Procede de production d'acier en convertisseur basique avec utilisation de latier
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

Family Applications After (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) EP0063569B1 (fr)
JP (1) JPH0259201B2 (fr)
DE (1) DE3040630C2 (fr)
WO (1) WO1982001565A1 (fr)

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

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
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

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8201565A1 *

Also Published As

Publication number Publication date
DE3040630A1 (de) 1982-04-29
EP0050743A1 (fr) 1982-05-05
US4421554A (en) 1983-12-20
WO1982001565A1 (fr) 1982-05-13
DE3040630C2 (de) 1983-03-31
EP0063569B1 (fr) 1986-01-08
JPH0259201B2 (fr) 1990-12-11
JPS57501863A (fr) 1982-10-21

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