EP0220522A1 - Mixture for desulfurizing metal melts, process for manufacturing it and its use - Google Patents

Mixture for desulfurizing metal melts, process for manufacturing it and its use Download PDF

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EP0220522A1
EP0220522A1 EP86113501A EP86113501A EP0220522A1 EP 0220522 A1 EP0220522 A1 EP 0220522A1 EP 86113501 A EP86113501 A EP 86113501A EP 86113501 A EP86113501 A EP 86113501A EP 0220522 A1 EP0220522 A1 EP 0220522A1
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Prior art keywords
desulfurization
mixture according
percent
desulfurization mixture
mixture
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EP0220522B1 (en
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Hermann Dr. Schrödter
Albert Braun
Friedrich-Wilhelm Dr. Kampmann
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Hoechst AG
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Hoechst AG
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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
    • C21C1/00—Refining of pig-iron; Cast iron
    • C21C1/02—Dephosphorising or desulfurising
    • C21C1/025—Agents used for dephosphorising or desulfurising

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  • the present invention relates to a desulfurization mixture for molten metals based on calcium carbide, calcium oxide, alkaline earth carbonate, aluminum oxide, chemically unbound carbon and optionally alkali carbonate, a process for its preparation and its use.
  • DE-PS 20 37 758 describes a special calcium carbide in which a mixture of burnt lime and fluorspar is introduced into the calcium carbide melt and then the solidified calcium carbide is crushed.
  • the disadvantage of this process was that only about 2/3 of the fluorine used remained in the melt.
  • DE-PS 26 42 838 describes a process for desulfurizing steel, in which a mixture of calcium carbide with 5 to 25 percent by weight calcium fluoride is added to the metal melt under reduced pressure. It has been shown that this mixture is not suitable for dosing via a submersible lance, since caking occurs in the lance during the blowing process. In addition, slag incrustations form on the pan walls. This desulfurization mixture can be used successfully if there is no slag on the metal bath at first.
  • the object of the present invention is to produce a desulfurization mixture which has a high degree of desulfurization in metals, in particular in iron melts such as pig iron, cast iron and steel melts, with the formation of a crumbly slag and allows perfect metering via an immersion lance.
  • a process is also to be specified which allows the production of this desulfurization mixture without the formation of fluoride-containing exhaust gases.
  • the desulfurization mixture should be able to be brought into contact with the liquid metal without any problems by blowing.
  • the desulfurization mixture according to the invention consists in particular of A preferred desulfurization mixture results if it contains 0.25 to 1.7 percent by weight of fluorine, which is preferably introduced as fluorspar, and if an industrial carbide with a CaC 2 content of 20 to 80 percent by weight is used.
  • the content of pure CaC 2 in the carbide furnace is set, or the content of pure CaC 2 in the liquid phase in the crucible is adjusted by lean with quicklime or the content of pure CaC 2 in the carbide furnace is rough adjusted and then finally adjusted in the liquid phase in the crucible by adding quicklime.
  • the desulfurization mixture according to the invention can contain up to 30 percent by weight of alkali carbonate, preferably in the form of anhydrous soda.
  • the starting materials should have a grain size of 0.1 to 50 mm, preferably 0.2 to 20 mm, as a homogeneous mixture by grinding in a mill under a dry inert gas atmosphere to a size of ⁇ 0.5 mm are ground and the ground material has an average residence time of 3 to 30, preferably 10 to 20 minutes in the mill.
  • the grinding process is of great importance for the production of an optimal mixture with regard to flowability and desulfurization.
  • a preferred embodiment of the process according to the invention is obtained if at least 85% by weight of the end product is ground to a grain size of ⁇ 0.1 mm by the grinding process, since this desulphurization mixture can then be added to the liquid metal in an amount of 0.5 to 5. 0 kg / t metal can be blown in with a carrier gas via a submersible lance.
  • the desulfurization mixture does not cause caking, neither in the lance nor in its feed pipes. It has also been shown that there is no slag encrustation on the metal when using the desulfurization mixture pan wall comes.
  • the emission of undesired fluoride emissions during the desulfurization process is significantly lower compared to a calcium carbide / calcium fluoride mixture produced in the usual ways.
  • the sulfur content was reduced from 0.024 to 0.0025 percent S.
  • the sulfur content was reduced from 0.025 to 0.0007 percent S.

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  • 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)
  • Carbon Steel Or Casting Steel Manufacturing (AREA)

Abstract

Mixture for desulfurizing metal melts based on calcium carbide, calcium oxide, alkaline earth metal carbonates, aluminum oxide, chemically unbonded carbon and alkali metal carbonates, if any. The desulfurizing mixture contains 0.3-4.5 wgt % calcium fluoride as an additional constituent and is produced by grinding the individual constituents jointly in a mill over a period of 3-30 minutes.

Description

Vorliegende Erfindung betrifft ein Entschwefelungsgemisch für Metallschmelzen auf der Basis von Calciumcarbid, Calciumoxid, Erdalkalikarbonat, Aluminiumoxid, chemisch nicht gebundenem Kohlenstoff sowie gegebenenfalls Alkalikarbonat, ein Verfahren zu seiner Herstellung und seine Verwendung.The present invention relates to a desulfurization mixture for molten metals based on calcium carbide, calcium oxide, alkaline earth carbonate, aluminum oxide, chemically unbound carbon and optionally alkali carbonate, a process for its preparation and its use.

Durch die Verarbeitung von minderwertigen Eisenerzen sowie Schrott im Konverter und durch den steigenden Einsatz von höher schwefelhaltigem Koks bzw. Ölkoks gewinnt die Entschwefelung von Roheisen zunehmend an Bedeutung. Nur durch die Entschwefelung der Eisenschmelze können die heute in zunehmenden Mengen verarbeiteten hochwertigen schwefelarmen Stähle zur Verfügung gestellt werden.The processing of low-quality iron ores and scrap in the converter and the increasing use of high-sulfur coke and oil coke mean that the desulfurization of pig iron is becoming increasingly important. Only through the desulphurization of the molten iron can the high-quality, low-sulfur steels processed today in increasing quantities be made available.

In der Technik hat es deshalb nicht an Versuchen gefehlt, wirksame Entschwefelungsmittel bereitzustellen. Von einer reinen Kalkentschwefelung kam man bald ab, da diese Entschwefelung eine FeO-arme Schlacke verlangt und ein heißes Schmelzen erforderlich macht, wodurch eine gesteigerte unerwünschte Silizium-Reduktion eintritt. Durch die Zugabe von Calciumcarbid, insbesondere wenn das Calciumcarbid mit Calciumoxid gemagert ist, konnte die Behandlungstemperatur der Metallschmelze abgesenkt werden.There has been no shortage of attempts in the art to provide effective desulfurization agents. Pure desulphurization was soon abandoned, since this desulphurization requires a low-FeO slag and requires hot melting, which leads to an increased undesirable silicon reduction. The treatment temperature of the molten metal could be reduced by adding calcium carbide, especially if the calcium carbide is leaned with calcium oxide.

In der DE-PS.20 37 758 wird ein spezielles Calciumcarbid beschrieben, bei dem in die Calciumcarbidschmelze ein Gemisch aus gebranntem Kalk und Flußspat eingetragen wird und anschließend das erstarrte Calciumcarbid zerkleinert wird. Nachteilig bei diesem Verfahren war, daß nur etwa 2/3 des eingesetzten Fluors in der Schmelze verblieb.DE-PS 20 37 758 describes a special calcium carbide in which a mixture of burnt lime and fluorspar is introduced into the calcium carbide melt and then the solidified calcium carbide is crushed. The disadvantage of this process was that only about 2/3 of the fluorine used remained in the melt.

In der DE-PS 26 42 838 wird ein Verfahren zum Entschwefeln von Stahl beschrieben, bei dem ein Gemisch aus Calciumcarbid mit 5 bis 25 Gewichtsprozent Calciumfluorid der Metallschmelze unter Unterdruck zugesetzt wird. Es hat sich gezeigt, daß dieses Gemisch nicht zur Dosierung über eine Tauchlanze geeignet ist, da es bei dem Blasvorgang zu Anbackungen in der Lanze kommt. Außerdem bilden sich Schlackenverkrustungen an den Pfannenwänden. Dieses Entschwefelungsgemisch kann dann mit Erfolg angewandt werden, wenn anfangs keine Schlacke auf dem Metallbad ist.DE-PS 26 42 838 describes a process for desulfurizing steel, in which a mixture of calcium carbide with 5 to 25 percent by weight calcium fluoride is added to the metal melt under reduced pressure. It has been shown that this mixture is not suitable for dosing via a submersible lance, since caking occurs in the lance during the blowing process. In addition, slag incrustations form on the pan walls. This desulfurization mixture can be used successfully if there is no slag on the metal bath at first.

Aufgabe der vorliegenden Erfindung ist es, ein Entschwefelungsgemisch herzustellen, daß einen hohen Entschwefelungsgrad bei Metallen, insbesondere.bei Eisenschmelzen wie Roheisen-, Gußeisen- und Stahlschmelzen, unter Bildung einer krümeligen Schlacke hat und eine einwandfreie Dosierung über eine Tauchlanze erlaubt. Weiter soll ein Verfahren angegeben werden, das die Herstellung dieses Entschwefelungsgemisches ohne Bildung fluoridhaltiger Abgase erlaubt. Das Entschwefelungsgemisch soll problemlos über einen Blasvorgang mit dem flüssigen Metall in Berührung gebracht werden können.The object of the present invention is to produce a desulfurization mixture which has a high degree of desulfurization in metals, in particular in iron melts such as pig iron, cast iron and steel melts, with the formation of a crumbly slag and allows perfect metering via an immersion lance. A process is also to be specified which allows the production of this desulfurization mixture without the formation of fluoride-containing exhaust gases. The desulfurization mixture should be able to be brought into contact with the liquid metal without any problems by blowing.

Überraschenderweise hat sich nun gezeigt, daß sich ein gutes Entschwefelungsgemisch für Metallschmelzen auf der Basis von Calciumcarbid, Calciumoxid, Erdalkalikarbonat, Aluminiumoxid, chemisch nicht gebundenem Kohlenstoff sowie gegebenenfalls Alkalikarbonat ergibt, wenn das Gemisch 0,3 bis 4,5 Gewichtsprozent Calciumfluorid enthält, eine Körnung von kleiner 0,5 mm besitzt und erhalten wurde durch gemeinsame Aufmahlung der Ausgangskomponenten während einer Verweilzeit des Mahlgutes in der Mühle von 3 bis 30, vorzugsweise 10 bis 20 Minuten.Surprisingly, it has now been found that a good desulfurization mixture for molten metals based on calcium carbide, calcium oxide, alkaline earth carbonate, aluminum oxide, chemically unbound carbon and optionally alkali carbonate results in a grain if the mixture contains 0.3 to 4.5 percent by weight calcium fluoride of less than 0.5 mm and was obtained by grinding the starting components together during a residence time of the ground material in the mill of 3 to 30, preferably 10 to 20 minutes.

Das erfindungsgemäße Entschwefelungsgemisch besteht insbesondere aus

Figure imgb0001
Ein vorzugsweises Entschwefelungsgemisch resultiert, wenn es 0,25 bis 1,7 Gewichtsprozent Fluor enthält, das vorzugsweise als Flußspat eingebracht wird, und wenn ein technisches Carbid mit einem CaC2-Gehalt von 20 bis 80 Gewichtsprozent verwendet wird.The desulfurization mixture according to the invention consists in particular of
Figure imgb0001
 A preferred desulfurization mixture results if it contains 0.25 to 1.7 percent by weight of fluorine, which is preferably introduced as fluorspar, and if an industrial carbide with a CaC 2 content of 20 to 80 percent by weight is used.

Hierbei spielt es keine Rolle, ob ein technisches Calciumcarbid verwendet wird, dessen Gehalt an reinem CaC2 im Carbidofen eingestellt oder dessen Gehalt an reinem CaC2 in der flüssigen Phase im Tiegel durch Magern mit Branntkalk eingestellt oder dessen Gehalt an reinem CaC2 im Carbidofen grob eingestellt und danach in der flüssigen Phase im Tiegel durch Zugabe von Branntkalk endgültig eingestellt wurde.It does not matter whether a technical calcium carbide is used, the content of pure CaC 2 in the carbide furnace is set, or the content of pure CaC 2 in the liquid phase in the crucible is adjusted by lean with quicklime or the content of pure CaC 2 in the carbide furnace is rough adjusted and then finally adjusted in the liquid phase in the crucible by adding quicklime.

Für die Herstellung des Entschwefelungsgemisches kann als Erdalkalicarbonat Kalkstein und/oder Dolomit verwendet werden. Schließlich kann das erfindungsgemäße Entschwefelungsgemisch bis zu 30 Gewichtsprozent Alkalikarbonat, vorzugsweise in Form wasserfreier Soda, enthalten.Limestone and / or dolomite can be used as the alkaline earth carbonate to produce the desulfurization mixture. Finally, the desulfurization mixture according to the invention can contain up to 30 percent by weight of alkali carbonate, preferably in the form of anhydrous soda.

Bei dem erfindungsgemäßen Verfahren zur Herstellung dieses Entschwefelungsgemisches sollen die Ausgangsstoffe in einer Körnung von 0,1 bis 50 mm, vorzugsweise 0,2 bis 20 mm, als homogene Mischung durch einen Mahlvorgang unter trockener Inertgasatmosphäre in einer Mühle auf eine Größe von < 0,5 mm aufgemahlen werden und das Mahlgut eine durchschnittliche Verweilzeit von 3 bis 30, vorzugsweise 10 bis 20 Minuten in der Mühle haben.In the process according to the invention for producing this desulfurization mixture, the starting materials should have a grain size of 0.1 to 50 mm, preferably 0.2 to 20 mm, as a homogeneous mixture by grinding in a mill under a dry inert gas atmosphere to a size of <0.5 mm are ground and the ground material has an average residence time of 3 to 30, preferably 10 to 20 minutes in the mill.

Der Mahlvorgang, insbesondere die Mahldauer,ist für die Herstellung eines optimalen Gemisches hinsichtlich Fließfähigkeit und Entschwefelungswirkung von großer Bedeutung. Durch Erhöhung der Mindestmahldauer von ca. 5 Minuten auf 10 bis 20 Minuten erhält man durch Vergrößerung des tribochemischen Mahleffektes optimale Ergebnisse.The grinding process, especially the grinding time, is of great importance for the production of an optimal mixture with regard to flowability and desulfurization. By increasing the minimum grinding time from approx. 5 minutes to 10 to 20 minutes, optimal results are obtained by increasing the tribochemical grinding effect.

Als Inertgas wird aus Kostengründen Stickstoff bevorzugt. Eine vorzugsweise Ausgestaltung des erfindungsgemäßen Verfahrens ist dann gegeben, wenn durch den Mahlvorgang mindestens 85 Gewichtsprozent des Endproduktes auf eine Korngröße von <0,1 mm aufgemahlen werden, da dann dieses Entschwefelungsgemisch problemlos in das flüssige Metall in einer Menge von 0,5 bis 5,0 kg/t Metall über eine Tauchlanze mit einem Trägergas eingeblasen werden kann.For reasons of cost, nitrogen is preferred as the inert gas. A preferred embodiment of the process according to the invention is obtained if at least 85% by weight of the end product is ground to a grain size of <0.1 mm by the grinding process, since this desulphurization mixture can then be added to the liquid metal in an amount of 0.5 to 5. 0 kg / t metal can be blown in with a carrier gas via a submersible lance.

Mit dem erfindungsgemäß hergestellten Entschwefelungsgemisch ist eine bessere Entschwefelung von Eisenschmelzen wie Roheisen-, Gußeisen- und Stahlschmelzen, bezogen auf die eingesetzte CaC2-Menge, möglich.With the desulfurization mixture produced according to the invention, better desulfurization of molten iron such as pig iron, cast iron and steel melts, based on the amount of CaC 2 used , is possible.

Das Entschwefelungsgemisch führt auf Grund der guten Fließfähigkeit zu keinen Anbackungen, weder in der Lanze noch in deren Zuführungsrohren. Es hat sich weiter gezeigt, daß es bei der Verwendung des Entschwefelungsgemisches zu keinen Schlackenverkrustungen an der Metallpfannenwand kommt. Der Ausstoß an unerwünschten Fluorid-Emissionen während des Entschwefelungsvorganges ist wesentlich niedriger gegenüber einem auf bisher üblichen Wegen hergestellten Calciumcarbid/Calciumfluorid-Gemisch.Due to the good flowability, the desulfurization mixture does not cause caking, neither in the lance nor in its feed pipes. It has also been shown that there is no slag encrustation on the metal when using the desulfurization mixture pan wall comes. The emission of undesired fluoride emissions during the desulfurization process is significantly lower compared to a calcium carbide / calcium fluoride mixture produced in the usual ways.

Die folgenden Beispiele dienen der näheren Erläuterung der erfindungsgemäßen Verfahren zur Herstellung und Anwendung der neuartigen Entschwefelungsgemischen.The following examples serve to explain the processes according to the invention for producing and using the novel desulfurization mixtures in more detail.

Herstellungsbeispiel 1Production Example 1

In einer Rohrmühle (Fa. Schriever & Co., Typ Hilda 1700) wurden stündlich 5000 kg eines Gemisches, bestehend aus 80 Prozent technischem Calciumcarbid (Körnung 7-15 mm, 34 Prozent CaC2), 10 Prozent Calciumkarbonat (Körnung 5-10 mm), 5 Prozent Koksgruß (Körnung <10 mm), 1,5 Prozent Bauxit (Körnung <0,3 mm) und 3,5 Prozent Flußspat (Körnung 3-15 mm; 44,0 Prozent F) unter Stickstoffatmosphäre aufgemahlen. Die durchschnittliche Verweildauer des Mahlgutes in der Mühle betrug 15 Minuten. 1In a tube mill (Schriever & Co., type Hilda 1700) 5000 kg per hour of a mixture consisting of 80 percent technical calcium carbide (grain size 7-15 mm, 34 percent CaC 2 ), 10 percent calcium carbonate (grain size 5-10 mm) ), 5 percent coke powder (grain size <10 mm), 1.5 percent bauxite (grain size <0.3 mm) and 3.5 percent fluorspar (grain size 3-15 mm; 44.0 percent F) ground under a nitrogen atmosphere. The average residence time of the millbase in the mill was 15 minutes. 1

Das erhaltene Entschwefelungsgemisch hat folgende Analysenwerte:

  • Körnung 99,7 Prozent <0,5 mm, 90,1 Prozent < 0,1 mm. Der Fluorgehalt von 1,5 Prozent entspricht dem der verarbeiteten Rohstoffe.
The desulfurization mixture obtained has the following analytical values:
  • Grain size 99.7 percent <0.5 mm, 90.1 percent <0.1 mm. The fluorine content of 1.5 percent corresponds to that of the processed raw materials.

Herstellungsbeispiel 2Production Example 2

In einer wie in Beispiel 1 verwendeten Rohrmühle wurden stündlich 4000 kg eines Gemisches, bestehend aus 70 Prozent technischem Calciumcarbid (Körnung 7-15 mm; 34 Prozent CaC2), 25 Prozent Calciumkarbonat (Körnung 5-10 mm), 2,0 Prozent Koksgruß (Körnung < 10 mm) und 3,0 Prozent Flußspat (Körnung 3-15 mm; 44,0 Prozent F) unter Stickstoffatmosphäre aufgemahlen. Die durchschnittliche Verweilzeit des Mahlgutes in der Mühle betrug 20 Minuten. Das erhaltene Entschwefelungsgemisch hat folgende Analysenwerte:

  • Körnung 99,8 Prozent < 0,5 mm, 90,1 Prozent <0,1 mm. Die chemische Analyse ergab, daß das Entschwefelungsgemisch 1,32 Prozent F, 2,3 Prozent Al2O3 und 0,5 Prozent Mg0 enthielt. Das Mg0 entstammt den Rohstoffen.
In a tube mill used as in Example 1, 4000 kg per hour of a mixture consisting of 70 percent technical calcium carbide (grain size 7-15 mm; 34 percent CaC 2 ), 25 percent calcium carbonate (grain size 5-10 mm), 2.0 percent coke (Grain size <10 mm) and 3.0 percent fluorspar (grain size 3-15 mm; 44.0 percent F) ground under a nitrogen atmosphere. The average residence time the millbase in the mill was 20 minutes. The desulfurization mixture obtained has the following analytical values:
  • Grain size 99.8 percent <0.5 mm, 90.1 percent <0.1 mm. Chemical analysis showed that the desulfurization mixture contained 1.32 percent F, 2.3 percent Al 2 O 3 and 0.5 percent MgO. The Mg0 comes from the raw materials.

Anwendungsbeispiel 1Application example 1

In eine mit 350 t flüssigem Roheisen gefüllte Torpedopfanne wurden bei einer Schmelzetemperatur von 1392°C während 17 Minuten 880 kg Entschwefelungsgemisch,hergestellt gemäß Herstellungsbeispiel 1, entsprechend 2,5 kg Entschwefelungsgemisch/t Roheisen, durch eine Tauchlanze (Tauchtiefe 2,05 m) mit 20 000 1 trockenem Stickstoff eingeblasen. Der Schwefelgehalt wurde von 0,06 auf 0,005 Prozent S gesenkt.In a torpedo pan filled with 350 t of liquid pig iron, 880 kg of desulfurization mixture, produced according to production example 1, corresponding to 2.5 kg of desulfurization mixture / t of pig iron, were passed through a dip lance (immersion depth 2.05 m) at a melt temperature of 1392 ° C. for 17 minutes 20,000 1 of dry nitrogen are blown in. The sulfur content was reduced from 0.06 to 0.005 percent S.

Anwendungsbeispiel 2Example of use 2

In eine mit 150 t flüssigem Stahl gefüllte Metallpfanne wurden bei einer Schmelzetemperatur von 1490°C 200 kg Entschwefelungsgemisch,hergestellt gemäß Herstellungsbeispiel 2, entsprechend 1,3 kg Entschwefelungsgemisch/t Stahl, mit 4000 1 Argon über eine Tauchlanze eingeblasen. Die Tauchlanze hatte eine Eintauchtiefe von 2,35 m.In a metal pan filled with 150 t of liquid steel, 200 kg of desulfurization mixture, produced according to Production Example 2, corresponding to 1.3 kg of desulfurization mixture / t steel, were injected with 4000 l of argon at a melt temperature of 1490 ° C. using an immersion lance. The diving lance had a depth of 2.35 m.

Der Schwefelgehalt wurde von 0,024 auf 0,0025 Prozent S gesenkt.The sulfur content was reduced from 0.024 to 0.0025 percent S.

Anwendungsbeispiel 3Example of use 3

In eine mit 150 t flüssigem Stahl gefüllte Metallpfanne wurden bei einer Schmelzetemperatur von 1480°C 400 kg Entschwefelungsgemisch,hergestellt gemäß Herstellungsbeispiel 2, entsprechend 2,7 kg Entschwefelungsgemisch/t Stahl, mit 8000 1 Argon über eine Tauchlanze eingeblasen. Die Tauchlanze hatte eine Eintauchtiefe von 2,35 m.In a metal pan filled with 150 t of liquid steel, 400 kg were melted at 1480 ° C Desulphurization mixture, produced according to production example 2, corresponding to 2.7 kg desulphurization mixture / t steel, blown in with 8000 1 argon via an immersion lance. The diving lance had a depth of 2.35 m.

Der Schwefelgehalt wurde von 0,025 auf 0,0007 Prozent S gesenkt.The sulfur content was reduced from 0.025 to 0.0007 percent S.

Claims (13)

1) Entschwefelungsgemisch für Metallschmelzen auf der Basis von Calciumcarbid, Calciumoxid, Erdalkalikarbonat, Aluminiumoxid, chemisch nicht gebundenem Kohlenstoff sowie gegebenenfalls Alkalikarbonat, dadurch gekennzeichnet, daß das Gemisch zusätzlich 0,3 bis 4,5 Gewichtsprozent Calciumfluorid enthält, eine Körnung von kleiner 0,5 mm besitzt und erhalten wurde durch gemeinsame Aufmahlung der Komponenten während einer Verweilzeit des Mahlgutes in der Mühle von 3 bis 30, vorzugsweise 10 bis 20 Minuten.1) Desulfurization mixture for molten metals based on calcium carbide, calcium oxide, alkaline earth carbonate, aluminum oxide, chemically unbound carbon and optionally alkali carbonate, characterized in that the mixture additionally contains 0.3 to 4.5 percent by weight calcium fluoride, a grain size of less than 0.5 mm has and has been obtained by grinding the components together during a residence time of the ground material in the mill of 3 to 30, preferably 10 to 20 minutes. 2) Entschwefelungsgemisch nach Anspruch 1, bestehend aus
Figure imgb0002
 2) Desulfurization mixture according to claim 1, consisting of
Figure imgb0002
 3) Entschwefelungsgemisch nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß es 0,25 bis 1,7 Gewichtsprozent Fluor enthält, das vorzugsweise als Flußspat eingebracht wird.3) Desulfurization mixture according to claim 1 or 2, characterized in that it contains 0.25 to 1.7 weight percent fluorine, which is preferably introduced as fluorspar. 4) Entschwefelungsgemisch nach Anspruch 1 bis 3, dadurch gekennzeichnet, daß ein technisches Carbid verwendet wird mit einem CaC2-Gehalt von 20 bis 80 Gewichtsprozent.4) Desulfurization mixture according to claim 1 to 3, characterized in that an industrial carbide is used with a CaC 2 content of 20 to 80 percent by weight. 5) Entschwefelungsgemisch nach Anspruch 4, dadurch gekennzeichnet, daß ein technisches Calciumcarbid verwendet wird, dessen Gehalt an reinem CaC2 im Carbidofen eingestellt wurde.5) Desulfurization mixture according to claim 4, characterized in that a technical calcium carbide is used, the content of pure CaC 2 was set in the carbide furnace. 6) Entschwefelungsgemisch nach Anspruch 4, dadurch gekennzeichnet, daß ein technisches Calciumcarbid verwendet wird, dessen Gehalt an reinem CaC2 in der flüssigen Phase im Tiegel durch Magern mit Branntkalk eingestellt wurde.6) Desulfurization mixture according to claim 4, characterized in that a technical calcium carbide is used, the content of pure CaC 2 in the liquid phase in the crucible was set by lean with quicklime. 7) Entschwefelungsgemisch nach Anspruch 4, dadurch gekennzeichnet, daß ein technisches Calciumcarbid verwendet wird, dessen Gehalt an reinem CaC2 im Carbidofen grob eingestellt und danach in der flüssigen Phase im Tiegel durch Zugabe von Branntkalk endgültig eingestellt wurde.7) Desulfurization mixture according to claim 4, characterized in that a technical calcium carbide is used, the content of pure CaC 2 in the carbide furnace was roughly adjusted and then finally adjusted in the liquid phase in the crucible by adding quicklime. 8) Entschwefelungsgemisch nach einem der Ansprüche 1 bis 7, dadurch gekennzeichnet, daß als Erdalkalicarbonat Kalkstein und/oder Dolomit verwendet wird.8) Desulfurization mixture according to one of claims 1 to 7, characterized in that limestone and / or dolomite is used as the alkaline earth carbonate. 9) Entschwefelungsgemisch nach einem der Ansprüche 1 bis 8, dadurch gekennzeichnet, daß es bis zu 30 Gewichtsprozent Alkalikarbonat, vorzugsweise wasserfreie Soda, enthält.9) Desulfurization mixture according to one of claims 1 to 8, characterized in that it contains up to 30 weight percent alkali carbonate, preferably anhydrous soda. 10) Verfahren zur Herstellung eines Entschwefelungsgemisches nach einem der Ansprüche 1 bis 9, dadurch gekennzeichnet, daß die Ausgangstoffe in einer Körnung von 0,1 bis 50 mm, vorzugsweise 0,2 bis 20 mm, als homogene Mischung durch einen Mahlvorgang unter trockener Inertgasatmosphäre in einer Mühle auf eine Größe von <0,5 mm aufgemahlen werden und das Mahlgut eine durchschnittliche Verweilzeit von 3 bis 30, vorzugsweise 10 bis 20 Minuten in der Mühle hat.10) Process for producing a desulfurization mixture according to one of claims 1 to 9, characterized in that the starting materials in a grain size of 0.1 to 50 mm, preferably 0.2 to 20 mm, as a homogeneous mixture by a milling process in a dry inert gas atmosphere in be ground in a mill to a size of <0.5 mm and the ground material has an average residence time of 3 to 30, preferably 10 to 20 minutes in the mill. 11) Verfahren nach Anspruch 10, dadurch gekennzeichnet, daß als Inertgas Stickstoff eingesetzt wird.11) Method according to claim 10, characterized in that nitrogen is used as the inert gas. 12) Verfahren nach Anspruch 10, dadurch gekennzeichnet, daß durch den Mahlvorgang mindestens 85 Gewichtsprozent des Endproduktes auf eine Korngröße von <0,1 mm aufgemahlen werden.12) Method according to claim 10, characterized in that at least 85 percent by weight of the end product are ground to a grain size of <0.1 mm by the grinding process. 13) Verfahren zur Entschwefelung von flüssigem Metall, dadurch gekennzeichnet, daß das Entschwefelungsgemisch gemäß einem der Ansprüche 1 bis 9 in das flüssige Metall in einer Menge von 0,5 bis 5,0 kg/t Metall über eine. Tauchlanze mit einem Trägergas eingeblasen wird.13) Process for the desulfurization of liquid metal, characterized in that the desulfurization mixture according to one of claims 1 to 9 in the liquid metal in an amount of 0.5 to 5.0 kg / t metal over a. Immersion lance is blown in with a carrier gas.
EP86113501A 1985-10-03 1986-10-01 Mixture for desulfurizing metal melts, process for manufacturing it and its use Expired EP0220522B1 (en)

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AT86113501T ATE48652T1 (en) 1985-10-03 1986-10-01 DESULPHURIZATION MIXTURE FOR METAL MELT, A PROCESS FOR ITS PRODUCTION AND ITS USE.

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DE19853535280 DE3535280A1 (en) 1985-10-03 1985-10-03 DESULFURATION MIXTURE FOR METAL MELTS, A METHOD FOR THE PRODUCTION THEREOF AND ITS USE
DE3535280 1985-10-03

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Cited By (2)

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EP0511121A1 (en) * 1991-04-02 1992-10-28 Pechiney Electrometallurgie Desulfurisation agent for pig iron, comprising calcium carbide and an organic binder
FR2679256A1 (en) * 1991-07-18 1993-01-22 Pechiney Electrometallurgie Desulphuriser for liquid pig iron based on agglomerated calcium carbide

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BR8606249A (en) * 1985-12-17 1987-09-29 Sueddeutsche Kalkstickstoff FINALLY GRANULATED COMPOSITION FOR THE DESULFURATION OF CAST IRON AND PROCESS FOR ITS PREPARATION
US4853033A (en) * 1988-06-29 1989-08-01 Electric Power Research Institute Method of desulfurizing molten metal in a plasma fired cupola
US4941914A (en) * 1989-05-18 1990-07-17 Elkem Metals Company Desulfurization agent
NO179080C (en) * 1989-05-18 1996-07-31 Elkem Metals Desulfurizing agent and process for the preparation of desulfurizing agent
DE4206091C2 (en) * 1992-02-27 1994-09-22 Anton Dr More Process for the desulfurization of molten iron with minimal slag accumulation and a suitable device
AT406690B (en) * 1994-12-09 2000-07-25 Donau Chemie Ag AGENT FOR TREATING RAW IRON AND CAST IRON MELT FOR THE PURPOSE OF DESULFURATION
PL213251B1 (en) 2009-02-02 2013-02-28 Akad Gorniczo Hutnicza Method of manufacturing slag-forming mixture for the secondary steel refining in a ladle or in a ladle furnace

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EP0061011A1 (en) * 1981-03-24 1982-09-29 Hoechst Aktiengesellschaft Process for producing desulfurizing agents for pig iron or steel melts
EP0070912A1 (en) * 1981-07-27 1983-02-09 Thyssen Aktiengesellschaft vorm. August Thyssen-Hütte Process for lowering the iron content of slags rich in CaO formed in the course of the desulphurisation of pig iron

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Publication number Priority date Publication date Assignee Title
EP0511121A1 (en) * 1991-04-02 1992-10-28 Pechiney Electrometallurgie Desulfurisation agent for pig iron, comprising calcium carbide and an organic binder
FR2679256A1 (en) * 1991-07-18 1993-01-22 Pechiney Electrometallurgie Desulphuriser for liquid pig iron based on agglomerated calcium carbide

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ES2012038B3 (en) 1990-03-01
DE3667493D1 (en) 1990-01-18
EP0220522B1 (en) 1989-12-13
US4687512A (en) 1987-08-18
DD249922A5 (en) 1987-09-23
DE3535280A1 (en) 1987-04-09
JPS6286108A (en) 1987-04-20
PL261682A1 (en) 1987-09-07
IN167748B (en) 1990-12-15
PL146624B1 (en) 1989-02-28
JPH0733534B2 (en) 1995-04-12
ATE48652T1 (en) 1989-12-15

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