EP0061012A1 - Procédé pour la fabrication d'agents de désulfuration de fonte et d'acier fondus - Google Patents

Procédé pour la fabrication d'agents de désulfuration de fonte et d'acier fondus Download PDF

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Publication number
EP0061012A1
EP0061012A1 EP82101428A EP82101428A EP0061012A1 EP 0061012 A1 EP0061012 A1 EP 0061012A1 EP 82101428 A EP82101428 A EP 82101428A EP 82101428 A EP82101428 A EP 82101428A EP 0061012 A1 EP0061012 A1 EP 0061012A1
Authority
EP
European Patent Office
Prior art keywords
weight
mixture
cao
cac
calcium oxide
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
EP82101428A
Other languages
German (de)
English (en)
Other versions
EP0061012B1 (fr
Inventor
Albert Braun
Willi Dr. Portz
Georg Dr. Strauss
Hans-Martin Dipl.-Ing. Delhey
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.)
Krupp Stahl AG
Hoechst AG
Original Assignee
Krupp Stahl AG
Hoechst 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 Krupp Stahl AG, Hoechst AG filed Critical Krupp Stahl AG
Priority to AT82101428T priority Critical patent/ATE9232T1/de
Publication of EP0061012A1 publication Critical patent/EP0061012A1/fr
Application granted granted Critical
Publication of EP0061012B1 publication Critical patent/EP0061012B1/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
    • 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
    • C21C7/0645—Agents used for 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
    • C21C1/00—Refining of pig-iron; Cast iron
    • C21C1/02—Dephosphorising or desulfurising
    • C21C1/025—Agents used for dephosphorising or desulfurising

Definitions

  • the invention relates to a mixture for desulfurizing metal melts, in particular steel and pig iron melts, on the basis of CaC 2 -CaO crystal mixtures obtained in the melt flow, and to a method for producing the mixture.
  • the known desulfurization mixtures especially for use by the immersion lance method, first had to be ground as finely as possible. According to this, these mixtures meet the requirements, but are expensive both in terms of manufacture and in terms of electrical energy consumption. Despite the fine grinding, relatively large amounts of the desulfurization mixtures had to be added in order to achieve the desired degree of desulfurization.
  • the object of the present invention is therefore to create a desulfurization mixture which offers a better degree of utilization and to provide an economical process for the production of this mixture.
  • the mixtures contain free carbon and carbonate and that part of the CaO 2 -CaO crystal mixture is hydrated to Ca (OH) 2 .
  • CaC 2 -CaO crystal mixtures with a proportion of 40 to 80% by weight Ca0 (corresponding to 20 to 60% by weight CaC 2 ), in particular 45 to 80% by weight Ca0 (corresponding to 20 to 55% by weight CaC 2 ) or 40 to 65 wt% Ca0 (corresponding to 35 to 60 wt% CaC 2 ).
  • the mixture according to the invention is furthermore preferably characterized in that it contains 1 to 6% by weight, preferably 2.5 to 3.5% by weight, of water chemically bound to calcium oxide.
  • the mixtures of the invention preferably contain 0.5 to 8% by weight of free carbon (for example coke breeze, anthracite, graphite, carbon black) and 0.5 to 20% by weight of carbonates of calcium, magnesium or Sodium.
  • free carbon for example coke breeze, anthracite, graphite, carbon black
  • Ca0 and CaC 2 crystallize as a crystal mixture in which the CaC 2 and CaO crystals are intertwined, namely at the specified CaC 2 / CaO quantity ratio with a lying in the area of the eutectic or shifted to the lime side hypoeutectic composition.
  • H 2 0 is added, part of the Ca0 in the crystal mixture reacts according to the equation without the CaC 2 grown together with the CaO crystals being substantially attacked by the H 2 0.
  • the grinding grains which consist of CaO-CaC 2 crystal growths in which part of the CaO crystals are hydrated, disintegrate at the prevailing temperatures above 800 ° C according to the following reaction equation
  • the grinding grain Because of the gas development at the reactive crystal interfaces, the grinding grain literally bursts with the release of lime, which is highly reactive in statu nascendi, and with enlargement of the CaO-CaC 2 crystal surfaces grown together in the grain. With an almost eutectic crystal structure, there is an ideally large reaction surface.
  • the reducing gases released offer ideal conditions for the implementation of Ca0 with the sulfur dissolved in the molten metal.
  • Such a desulfurization mixture is particularly suitable for desulfurization processes in which the time for the conversion of the desulfurization mixture with the sulfur is very short.
  • This process includes the immersion lance process, in which the desulfurization mixture should be converted as completely as possible by blowing desulfurization mixtures into a metal melt below its surface in the short time from the exit of the desulfurization mixture into the melt until it rises to the bath surface.
  • the desulfurization mixture according to the invention is superior to the best known carbide-based mixtures in the desulfurization effect. Because of the intergranular gas reaction in the grinding grain, the conversion of CaC 2 to Ca0 and the resulting enlargement of the crystal surfaces is more effective, the gas development is much the same more moderate and less violent than with known desulfurization mixtures, for example according to DE-AS 22 52 795, to which gas-releasing additives are mechanically mixed. Desulphurization therefore takes place more quietly and with less metal emissions, particularly in the open pan and the torpedo pan.
  • the material can be used in a coarser manner, so that expensive fine grinding can be dispensed with.
  • the use of the desulfurization mixture according to the invention enables greater accuracy with regard to the final content required in each case.
  • the production costs for the mixture according to the invention are considerably lower than for known agents based on carbide.
  • a process for producing the mixture according to the invention is proposed, which is characterized in that finely divided calcium oxide is introduced in an excess of 3 to 15% by weight in a calcium carbide melt produced in the customary manner, which already has a calcium oxide content of up to 45% by weight.
  • the calcium oxide which is introduced into the melt, is preheated to temperatures up to 2000 ° C., preferably up to 1100 ° C., and is introduced hot into the melt at these temperatures, it is possible to determine the CaO content in the carbide to increase to 80% by weight, the preheating being chosen the higher, the higher the desired proportion of additionally dissolved calcium oxide should be between 40 and 80% by weight. This enables use in low-carbon pig iron and steel melts and also increases the desulfurization yield, based on calcium carbide.
  • the portions smaller than 4 mm which have been screened off after the preliminary crushing essentially consist of Ca0 and can be returned to the process as finely divided calcium oxide, where they together with fresh Ca0 as the starting pro duct serve. It was not foreseeable for the person skilled in the art that, by sieving off the fractions smaller than 4 mm after the preliminary breaking, those fractions which have no or only a slight desulfurization effect are removed from the product, and the effectiveness of the end product is thus considerably increased.
  • the product produced according to the invention can be ground much better than products obtained by known processes. This is particularly important because in some cases the product has to be used with a grain size of less than 0.1 mm.
  • Calcium carbide for example electrothermally, is produced in a known manner from lime and coke, the lime-coke mixture in the Möller being adjusted to a weight ratio of 100:40, which corresponds to a carbide with a CaO content of approximately 40% by weight.
  • Ca0 with a grain size of 3 to 8 mm and a Ca (OH) 2 - and CaC0 3 content of less than 1% by weight each is injected into the jet of the molten carbide which has been tapped from the furnace into a crucible at such a rate and in such a rate Amounts entered that, until the crucible is filled, there is a total CaC 2 : CaO weight ratio of 43:57, which is an excess of 14% by weight CaO, based on the CaO content of 50 desired in the CaC 2 -CaO crystal mixture % By weight.
  • the mixture is then cooled until the average temperature of the solidified carbide block is approximately 400 ° C., and the block is pre-crushed to sizes smaller than 150 mm.
  • the fractions smaller than 4 mm obtained during the preliminary crushing essentially contain the CaO used in excess, while the remaining product with grain sizes larger than 4 mm represents a crystal mixture of 50% by weight CaC 2 and 50% by weight Ca0.
  • 850 kg of this CaC 2 -CaO crystal mixture are mixed with 100 kg of limestone (grain size less than 1 mm) and 50 kg of coke breeze (grain size less than 3 mm) and by passing 1500 m 3 / h of air with a moisture content of 10 g / m 3 (at 15 ° C) in a rotary mill with a throughput of 500 kg / h at 50 ° C to grain sizes smaller than 0.1 mm.
  • the screened grain fraction smaller than 4 mm is used together with fresh lime (Ca0) as the starting product.
  • the product obtained contains 2% by weight of chemically bound water.
  • Example 2 The procedure is as in Example 1, with the changes that the Ca0 is preheated to a temperature of about 1100 ° C. and the amount of Ca0 is increased so that a total Ca0 content of 62.5 wt % results, which corresponds to an excess of 4% by weight, based on the desired content of 60% by weight CaO in the finished end product.
  • 1800 kg of the product worked up and ground according to the invention are used to desulfurize a 300 t steel melt with a sulfur content of 0.02% by weight at 1650 ° C.
  • the sulfur content of the melt is reduced to less than 0.005% by weight.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (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)
  • Manufacture And Refinement Of Metals (AREA)
  • Solid-Sorbent Or Filter-Aiding Compositions (AREA)
EP82101428A 1981-03-24 1982-02-25 Procédé pour la fabrication d'agents de désulfuration de fonte et d'acier fondus Expired EP0061012B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT82101428T ATE9232T1 (de) 1981-03-24 1982-02-25 Verfahren zur herstellung eines entschwefelungsmittels fuer roheisen- und stahlschmelzen.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3111510 1981-03-24
DE19813111510 DE3111510A1 (de) 1981-03-24 1981-03-24 Entschwefelungsgemisch und verfahren zu seiner herstellung

Publications (2)

Publication Number Publication Date
EP0061012A1 true EP0061012A1 (fr) 1982-09-29
EP0061012B1 EP0061012B1 (fr) 1984-09-05

Family

ID=6128140

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82101428A Expired EP0061012B1 (fr) 1981-03-24 1982-02-25 Procédé pour la fabrication d'agents de désulfuration de fonte et d'acier fondus

Country Status (10)

Country Link
US (1) US4395282A (fr)
EP (1) EP0061012B1 (fr)
JP (1) JPS57171611A (fr)
AT (1) ATE9232T1 (fr)
BR (1) BR8201621A (fr)
CA (1) CA1184385A (fr)
DD (1) DD202182A5 (fr)
DE (2) DE3111510A1 (fr)
ES (1) ES8302103A1 (fr)
ZA (1) ZA821940B (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2160896A (en) * 1984-06-27 1986-01-02 Boc Group Inc Agents for the removal of impurities from a molten metal and a process for producing same

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1240842A (fr) * 1984-05-16 1988-08-23 Heinrich Rellermeyer Methode et composition de desulfuration de la fonte grise en fusion
BR8606249A (pt) * 1985-12-17 1987-09-29 Sueddeutsche Kalkstickstoff Composicao finamente granulada para a dessulfuracao de ferro fundido e processo para sua preparacao
DE3908071A1 (de) * 1989-03-13 1990-09-20 Hoechst Ag Mittel und verfahren zum entschwefeln von metallschmelzen
US5358550A (en) * 1992-10-26 1994-10-25 Rossborough Manufacturing Company Desulfurization agent
US5407459A (en) * 1993-09-23 1995-04-18 Alcan International Limited Process for the preparation of calcium aluminates from aluminum dross residues
AT406690B (de) * 1994-12-09 2000-07-25 Donau Chemie Ag Mittel zur behandlung von roheisen- und gusseisenschmelzen zum zweck der entschwefelung
US6238633B1 (en) 1997-06-30 2001-05-29 Aluminum Waste Technology, Inc. Process for preparing calcium aluminate from aluminum dross
US6372014B1 (en) 2000-04-10 2002-04-16 Rossborough Manufacturing Co. L.P. Magnesium injection agent for ferrous metal
US6352570B1 (en) 2000-04-10 2002-03-05 Rossborough Manufacturing Co., Lp Magnesium desulfurization agent
US6770115B2 (en) * 2002-10-18 2004-08-03 Remacor, Inc. Process for magnesium granules
US6989040B2 (en) * 2002-10-30 2006-01-24 Gerald Zebrowski Reclaimed magnesium desulfurization agent
US7731778B2 (en) * 2006-03-27 2010-06-08 Magnesium Technologies Corporation Scrap bale for steel making process
US20080196548A1 (en) * 2007-02-16 2008-08-21 Magnesium Technologies Corporation Desulfurization puck

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2326539A1 (de) * 1973-05-24 1974-12-12 Sueddeutsche Kalkstickstoff Verfahren zur herstellung wasserhaltiger gemische auf basis calciumcarbid fuer die entschwefelung von metallschmelzen
DE2252795B2 (de) * 1972-10-27 1977-02-03 Süddeutsche Kalkstickstoff-Werke AG, 8223 Trostberg Entschwefelungsmittel fuer metallschmelzen mit wasserabspaltendem zusatz
DE2741588A1 (de) * 1977-09-15 1979-03-29 Sueddeutsche Kalkstickstoff Mittel zum entschwefeln von eisenschmelzen
DE2907069A1 (de) * 1979-02-23 1980-08-28 Krupp Ag Huettenwerke Mittel zur entschwefelung von metallschmelzen
EP0019086A2 (fr) * 1979-05-19 1980-11-26 Hoechst Aktiengesellschaft Procédé pour la fabrication d'agents de désulfurisation de fonte ou d'acier fondus
EP0031534A1 (fr) * 1979-12-29 1981-07-08 Hoechst Aktiengesellschaft Procédé pour la fabrication d'agents de désulfuration de fonte ou d'acier fondus
EP0031552A1 (fr) * 1979-12-29 1981-07-08 Hoechst Aktiengesellschaft Agent de désulfuration et procédé pour sa fabrication
EP0019087B1 (fr) * 1979-05-14 1983-07-20 Hoechst Aktiengesellschaft Matières de désulfuration pour bains de fonte et d'acier ainsi que procédé pour leur fabrication

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH428820A (fr) * 1963-12-12 1967-01-31 Tech Entwicklung Und Verwertun Produit d'affinage de l'acier
US3197306A (en) * 1964-08-31 1965-07-27 Dow Chemical Co Method for treating ferrous metals
DE1758250B1 (de) * 1968-04-29 1971-10-28 Sueddeutsche Kalkstickstoff Mittel zum Entschwefeln von Eisenschmelzen

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2252795B2 (de) * 1972-10-27 1977-02-03 Süddeutsche Kalkstickstoff-Werke AG, 8223 Trostberg Entschwefelungsmittel fuer metallschmelzen mit wasserabspaltendem zusatz
DE2326539A1 (de) * 1973-05-24 1974-12-12 Sueddeutsche Kalkstickstoff Verfahren zur herstellung wasserhaltiger gemische auf basis calciumcarbid fuer die entschwefelung von metallschmelzen
DE2741588A1 (de) * 1977-09-15 1979-03-29 Sueddeutsche Kalkstickstoff Mittel zum entschwefeln von eisenschmelzen
DE2907069A1 (de) * 1979-02-23 1980-08-28 Krupp Ag Huettenwerke Mittel zur entschwefelung von metallschmelzen
EP0019087B1 (fr) * 1979-05-14 1983-07-20 Hoechst Aktiengesellschaft Matières de désulfuration pour bains de fonte et d'acier ainsi que procédé pour leur fabrication
EP0019086A2 (fr) * 1979-05-19 1980-11-26 Hoechst Aktiengesellschaft Procédé pour la fabrication d'agents de désulfurisation de fonte ou d'acier fondus
EP0031534A1 (fr) * 1979-12-29 1981-07-08 Hoechst Aktiengesellschaft Procédé pour la fabrication d'agents de désulfuration de fonte ou d'acier fondus
EP0031552A1 (fr) * 1979-12-29 1981-07-08 Hoechst Aktiengesellschaft Agent de désulfuration et procédé pour sa fabrication

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2160896A (en) * 1984-06-27 1986-01-02 Boc Group Inc Agents for the removal of impurities from a molten metal and a process for producing same

Also Published As

Publication number Publication date
ATE9232T1 (de) 1984-09-15
ES510768A0 (es) 1983-02-01
JPH0152446B2 (fr) 1989-11-08
JPS57171611A (en) 1982-10-22
DD202182A5 (de) 1983-08-31
DE3260643D1 (en) 1984-10-11
ES8302103A1 (es) 1983-02-01
EP0061012B1 (fr) 1984-09-05
ZA821940B (en) 1983-02-23
DE3111510A1 (de) 1982-10-07
BR8201621A (pt) 1983-02-16
US4395282A (en) 1983-07-26
CA1184385A (fr) 1985-03-26

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