EP0019087B1 - Desulphurising agents for pig iron and steel melts, and process for their manufacture - Google Patents

Desulphurising agents for pig iron and steel melts, and process for their manufacture Download PDF

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Publication number
EP0019087B1
EP0019087B1 EP80101985A EP80101985A EP0019087B1 EP 0019087 B1 EP0019087 B1 EP 0019087B1 EP 80101985 A EP80101985 A EP 80101985A EP 80101985 A EP80101985 A EP 80101985A EP 0019087 B1 EP0019087 B1 EP 0019087B1
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EP
European Patent Office
Prior art keywords
weight
calcium oxide
less
size
temperatures
Prior art date
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Expired
Application number
EP80101985A
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German (de)
French (fr)
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EP0019087A1 (en
Inventor
Albert Braun
Willi Dr. Portz
Georg Dr. Strauss
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Hoechst AG
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Hoechst AG
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Priority to AT80101985T priority Critical patent/ATE4227T1/en
Publication of EP0019087A1 publication Critical patent/EP0019087A1/en
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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 present invention relates to desulfurizing agents for pig iron and steel melts based on a calcium carbide containing calcium oxide and to processes for their production.
  • carbide calcium carbide
  • lime calcium oxide
  • additives in the form of a mixture consisting of lime and fluorspar are added to the melt of a relatively high-percentage carbide, the grain size of the additives being less than 20 mm, preferably 0.5 to 10 mm, and their adhesive and crystal water content less than 5 % By weight, preferably less than 0.5% by weight.
  • carbide which has 20 to 55% by weight CaC 2 and a high CaO content of more than 45 to 80% by weight, is more suitable for desulfurizing hot metal and steel melts, especially then , if it was manufactured in a certain way, and that the relatively expensive fluorspar as an additive can also be dispensed with.
  • the desulfurizing agent according to the invention is obtained by heating calcium carbide melt in an existing and customarily produced manner, which already has a calcium oxide content of up to 45% by weight, at temperatures up to 2000.degree. preferably pre-heated to 1100 ° C, finely divided calcium oxide, in an excess of 3 to 15 wt .-%, based on the amount desired in the end product.
  • the temperature of the preheating is chosen to be higher, the higher the proportion of additionally dissolved calcium oxide between 45 and 80% by weight in the end product.
  • the mixture obtained is then solidified to temperatures of 350 to 450 ° C. and pre-broken at these temperatures to grain sizes smaller than 150 mm.
  • the inevitably occurring grain fraction smaller than 4 mm is then separated from the remaining product and the latter is crushed to exclude moisture by breaking and grinding to grain sizes smaller than 10 mm.
  • the product according to the invention is an excellent desulfurization agent for low-carbon pig iron and steel melts and is characterized by an increased desulfurization yield based on calcium carbide.
  • a calcium carbide melt is preferably used, which contains between 20 and 45% by weight of CaO.
  • the portions smaller than 4 mm which have been screened off after the preliminary crushing essentially consist of CaO and can be returned to the process as finely divided calcium oxide, where, together with fresh CaO, they serve as the starting product.
  • Calcium carbide e.g. produced electrothermally, 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 approx. 40% by weight.
  • CaO with a grain size of 3 to 8 mm and a Ca (OH) 2 and CaCO 3 content of less than 1 each is preheated to a temperature of about 1100 ° C. in the jet of the molten carbide, which has been tapped from the furnace into a crucible %
  • a total CaO content of 62.5% by weight results in the crucible, which corresponds to an excess of 4% by weight, based on that in the finished end product desired content of 60 wt .-% CaO.
  • the fractions of less than 4 mm obtained during preliminary crushing essentially contain the CaO used in excess, while the product with grain sizes larger than 4 mm remains an intensive mixture of 40% by weight CaC 2 and 60% by weight CaO, which then in the usual way smaller on grain sizes is ground as 10 mm.
  • the screened grain fraction smaller than 4 mm is used together with fresh lime as a starting product.
  • 1800 kg of the product worked up and ground according to the invention are used for the desulfurization of 300,000 kg of a 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.

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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)
  • Heat Treatment Of Steel (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Heat Treatment Of Strip Materials And Filament Materials (AREA)

Abstract

The invention provides an agent for desulfurizing crude iron and steel melts, the desulfurizing agent being based on calcium carbide containing calcium oxide. The desulfurizing agent is produced by admixing a calcium carbide melt having up to 45 weight % of calcium oxide therein with an excess of 3 to 15 weight %, based on the CaO-content of more than 45 up to 80 weight % desired for the final product, of calcium oxide. The resulting mixture is allowed to solidify and cool down to temperatures of 350 DEG to 450 DEG C. Next, the solidified melt is precrushed to material with a size of less than 150 mm. Particles with a size of less than 4 mm are screened off and the remaining material is comminuted, with the exclusion of moisture, to material with a size of less than 10 mm.

Description

Gegenstand der vorliegenden Erfindung sind Entschweflungsmittel für Roheisen- und Stahlschmelzen auf der Basis eines Calciumoxid enthaltenden Calciumcarbids sowie Verfahren zu deren Herstellung.The present invention relates to desulfurizing agents for pig iron and steel melts based on a calcium carbide containing calcium oxide and to processes for their production.

Es ist bereits bekannt, zur Entschweflung von Metallschmelzen Calciumcarbid (nachfolgend kurz als Carbid bezeichnet) einzusetzen, insbesondere solches Carbid, das neben Calciumoxid (nachfolgend kurz als Kalk bezeichnet) noch Flussspat enthält.It is already known to use calcium carbide (hereinafter referred to briefly as carbide) for the desulfurization of metal melts, in particular those carbide which, in addition to calcium oxide (hereinafter referred to briefly as lime), also contains fluorspar.

Die Herstellung eines solchen Entschweflungsmittels ist in der DE-C-2 037 758 beschrieben.The preparation of such a desulfurizing agent is described in DE-C-2 037 758.

Gemäss diesem bekannten Verfahren werden der Schmelze eines relativ hochprozentigen Carbides Zuschlagstoffe in Form eines aus Kalk und Flussspat bestehenden Gemisches zugesetzt, wobei die Körnung der Zuschlagstoffe weniger als 20 mm, vorzugsweise 0,5 bis 10 mm, und deren Haft-und Kristallwassergehalt weniger als 5 Gew.-%, vorzugsweise weniger als 0,5 Gew.-%, betragen soll.According to this known method, additives in the form of a mixture consisting of lime and fluorspar are added to the melt of a relatively high-percentage carbide, the grain size of the additives being less than 20 mm, preferably 0.5 to 10 mm, and their adhesive and crystal water content less than 5 % By weight, preferably less than 0.5% by weight.

Auf diese Weise gelingt es, Carbid herzustellen, das mehr als 45 bis 65% CaC2, aber nur etwa 25 bis 26,5% CaO enthält. Die Praxis hat jedoch gezeigt, dass Flussspat in derartigen Mischungen die Auskleidung aller Entschwefelungsgefässe stark angreift. Daher haben diese Mischungen anwendungstechnisch keine Bedeutung erlangt.In this way it is possible to produce carbide that contains more than 45 to 65% CaC2, but only about 25 to 26.5% CaO. However, practice has shown that fluorspar in such mixtures strongly attacks the lining of all desulfurization vessels. Therefore, these mixtures have no significance in terms of application technology.

Überraschenderweise hat sich jedoch gezeigt, dass sich Carbid, welcher 20 bis 55 Gew.-% CaC2 und einen hohen CaO-Gehalt von mehr als 45 bis 80 Gew.-% aufweist, besser zur Entschweflung von Roheisen- und Stahlschmelzen eignet, insbesondere dann, wenn es in einer bestimmten Weise hergestellt worden ist, und dass ausserdem auf den relativ teuren Flussspat als Zuschlagstoff verzichtet werden kann.Surprisingly, however, it has been shown that carbide, which has 20 to 55% by weight CaC 2 and a high CaO content of more than 45 to 80% by weight, is more suitable for desulfurizing hot metal and steel melts, especially then , if it was manufactured in a certain way, and that the relatively expensive fluorspar as an additive can also be dispensed with.

Das erfindungsgemässe Entschweflungsmittel erhält man dadurch, dass man in eine vorliegende und in üblicher Weise erzeugte Calciumcarbidschmelze, welche bereits einen Calciumoxidgehalt bis zu 45 Gew.-% aufweist, mit Temperaturen bis 2000°C. vorzugsweise bis 1100°C vorerhitztes, feinteiliges Catciumoxid einträgt, in einem Überschuss von 3 bis 15 Gew.-%, bezogen auf die im Endprodukt gewünschte Menge. Dabei wird die Temperatur der Vorerhitzung um so höher gewählt, je höher der Anteil an zusätzlich gelöstem Calciumoxid zwischen 45 und 80 Gew.-% im Endprodukt liegen soll. Dann wird die erhaltene Mischung unter Erstarren auf Temperaturen von 350 bis 450 °C abgekühlt und bei diesen Temperaturen auf Korngrössen kleiner als 150 mm vorgebrochen. Den dabei zwangsläufig anfallenden Kornanteil kleiner als 4 mm trennt man anschliessend vom verbleibenden Produkt ab und zerkleinert letzteres unter Feuchtigkeitsausschluss durch Brechen und Mahlen auf Korngrössen kleiner als 10 mm.The desulfurizing agent according to the invention is obtained by heating calcium carbide melt in an existing and customarily produced manner, which already has a calcium oxide content of up to 45% by weight, at temperatures up to 2000.degree. preferably pre-heated to 1100 ° C, finely divided calcium oxide, in an excess of 3 to 15 wt .-%, based on the amount desired in the end product. The temperature of the preheating is chosen to be higher, the higher the proportion of additionally dissolved calcium oxide between 45 and 80% by weight in the end product. The mixture obtained is then solidified to temperatures of 350 to 450 ° C. and pre-broken at these temperatures to grain sizes smaller than 150 mm. The inevitably occurring grain fraction smaller than 4 mm is then separated from the remaining product and the latter is crushed to exclude moisture by breaking and grinding to grain sizes smaller than 10 mm.

Zweckmässigerweise führt man diese sogenannte «Magerung» des Carbides unter Ausnutzung dessen Wärmeinhaltes in einem Tiegel durch.This so-called “leaning” of the carbide is expediently carried out in a crucible using the heat content thereof.

Das erfindungsgemässe Produkt ist ein ausgezeichnetes Entschweflungsmittel für kohlenstoffarme Roheisen- und Stahlschmelzen und zeichnet sich durch eine erhöhte Entschwefelungsausbeute bezogen auf Calciumcarbid aus.The product according to the invention is an excellent desulfurization agent for low-carbon pig iron and steel melts and is characterized by an increased desulfurization yield based on calcium carbide.

Vorzugsweise wird von einer Calciumcarbidschmelze ausgegangen, welche zwischen 20 und 45 Gew.-% CaO enthält.A calcium carbide melt is preferably used, which contains between 20 and 45% by weight of CaO.

Die nach dem Vorbrechen abgesiebten Anteile kleiner als 4 mm bestehen im wesentlichen aus CaO und können als feinteiliges Calciumoxid wieder in den Prozess zurückgeführt werden, wo sie, zusammen mit frischem CaO, als Ausgangsprodukt dienen.The portions smaller than 4 mm which have been screened off after the preliminary crushing essentially consist of CaO and can be returned to the process as finely divided calcium oxide, where, together with fresh CaO, they serve as the starting product.

Es empfiehlt sich, das Calciumoxid mit einer Korngrösse von 1 bis 8 mm einzusetzen und darauf zu achten, dass es Gehalte von jeweils weniger als 1 Gew.-% an Ca(OH)2 und CaC03 aufweist.It is advisable to use calcium oxide with a grain size of 1 to 8 mm and to ensure that it contains less than 1% by weight of Ca (OH) 2 and CaC0 3 .

Nicht vorhersehbar war für den Fachmann, dass durch das Absieben der nach dem Vorbrechen anfallenden Anteile kleiner als 4 mm aus dem Produkt die Anteile entfernt werden, welche keine oder nur eine geringe Entschweflungswirkung besitzen und so die Wirksamkeit des Endproduktes erheblich gesteigert wird. Überraschend war ferner, dass sich das erfindungsgemäss hergestellte Produkt auch wesentlich besser mahlen lässt als nach bekannten Verfahren erhaltene Produkte. Dies ist deshalb von besonderer Wichtigkeit, weil das Produkt in zahlreichen Fällen mit einer Körnung kleiner als 100 um eingesetzt werden muss.It was not foreseeable for the person skilled in the art that, by screening off the portions of less than 4 mm after the preliminary breaking, the portions which have no or only a slight desulfurization effect are removed from the product and thus the effectiveness of the end product is considerably increased. It was also surprising that the product produced according to the invention can also be ground much better than products obtained by known processes. This is of particular importance because in many cases the product has to be used with a grain size of less than 100 µm.

In bekannter Weise wird aus Kalk und Koks Calciumcarbid z.B. elektrothermisch hergestellt, wobei die Kalk-Koks-Mischung im Möller auf ein Gewichtsverhältnis von 100:40 eingestellt wird, was einem Carbid mit einem CaO-Gehalt von ca. 40 Gew.-% entspricht.Calcium carbide, e.g. produced electrothermally, 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 approx. 40% by weight.

In den Strahl des aus dem Ofen in einen Tiegel abgestochenen schmelzflüssigen Carbides wird auf eine Temperatur von etwa 1100 °C vorerhitztes CaO mit einer Körnung von 3 bis 8 mm und einem Ca(OH)2- und CaCO3-Gehalt von jeweils weniger als 1 Gew.-% mit einer solchen Geschwindigkeit und in solchen Mengen eingetragen, dass sich insgesamt im Tiegel ein CaO-Gehalt von 62,5 Gew.-% ergibt, was einem Überschuss von 4 Gew.-% entspricht, bezogen auf den im fertigen Endprodukt gewünschten Gehalt von 60 Gew.-% CaO. Dann wird abgekühlt, bis die Durchschnittstemperatur des dabei erstarrten Carbidblockes etwa 400°C beträgt und der Block auf Grössen kleiner als 150 mm vorgebrochen ist.CaO with a grain size of 3 to 8 mm and a Ca (OH) 2 and CaCO 3 content of less than 1 each is preheated to a temperature of about 1100 ° C. in the jet of the molten carbide, which has been tapped from the furnace into a crucible % By weight entered at such a rate and in such quantities that a total CaO content of 62.5% by weight results in the crucible, which corresponds to an excess of 4% by weight, based on that in the finished end product desired content of 60 wt .-% CaO. It is then cooled until the average temperature of the solidified carbide block is approximately 400 ° C. and the block has broken down to sizes smaller than 150 mm.

Die beim Vorbrechen anfallenden Anteile kleiner als 4 mm enthalten im wesentlichen das im Überschuss eingesetzte CaO, während das zurückbleibende Produkt mit Korngrössen grösser als 4 mm ein intensives Gemisch von 40 Gew.-% CaC2 und 60 Gew.-% CaO darstellt, das anschliessend in üblicher Weise auf Korngrössen kleiner als 10 mm gemahlen wird. Die abgesiebte Kornfraktion kleiner als 4 mm wird zusammen mit frischem Kalk wieder als Ausgangsprodukt eingesetzt.The fractions of less than 4 mm obtained during preliminary crushing essentially contain the CaO used in excess, while the product with grain sizes larger than 4 mm remains an intensive mixture of 40% by weight CaC 2 and 60% by weight CaO, which then in the usual way smaller on grain sizes is ground as 10 mm. The screened grain fraction smaller than 4 mm is used together with fresh lime as a starting product.

1800 kg des erfindungsgemäss aufgearbeiteten und gemahlenen Produktes werden zur Entschwefelung von 300 000 kg einer Stahlschmelze mit einem Schwefelgehalt von 0,02 Gew.-% bei 1650 °C eingesetzt. Dabei wird der Schwefelgehalt der Schmelze auf weniger als 0,005 Gew.-% gesenkt.1800 kg of the product worked up and ground according to the invention are used for the desulfurization of 300,000 kg of a 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.

Claims (5)

1. Desulfurizing agent for crude iron and steel melts based on calcium carbide containing calcium oxide, produced by introducing into an existing calcium carbide melt containing up to 45 weight% of calcium oxide an excess of 3 to 15 weight%, based on the CaO-content of 45 to 80 weight% desired for the final product, of fine particulate calcium oxide, preheated to temperatures up to 2000 °C - the preheating temperature selected being the higher the higher the proportion of additionally dissolved calcium oxide to be established within the range 45 to 80 weight% - cooling the mixture with solidification to temperatures of 350 to 450°C; precrushing the solidified melt at these temperatures to material with a size of less than 150 mm; separating invariably obtained particles with a size of less than 4 mm from the remaining material and crushing and grinding the latter material with the exclusion of moisture to particles with a size of less than 10 mm.
2. Process for making a desulfurizing agent for crude iron and steel melts based on calcium carbide containing calcium oxide which comprises: making a desulfurizing agent containing 20 to 55 weight% of calcium carbide and more than 45 up to 80 weight% of calcium oxide, by introducing into an existing calcium carbide melt produced in customary manner and having up to 45 weight% of calcium oxide already contained therein an excess of 3 to 15 weight%, based on the CaO-content desired for the final product, of fine particulate calcium oxide preheated to temperatures of up to 2000°C - the preheating temperature selected being the higher the higher the proportion of additionally dissolved calcium oxide to be established within the range 45 to 80 weight% - cooling the resulting mixture with solidification to temperatures of 350 to 450°C; precrushing the solidified melt at these temperatures to material with a size of less than 150 mm; separating invariably obtained particles with a size of less than 4 mm from the remaining material; crushing and grinding the latter material with the exclusion of moisture to particles with a size of less than 10 mm.
3. Process as claimed in claim 2, wherein the calcium oxide addition is effected inside a crucible.
4. Process as claimed in claim 2 or 3, wherein the calcium carbide melt used as feed melt contains 20 to 45 weight% of calcium oxide.
5. Process as claimed in any of claims 2 to 4, wherein the particles with a size of less than 4 mm screened off after the precrushing step are recycled into the process.
EP80101985A 1979-05-14 1980-04-14 Desulphurising agents for pig iron and steel melts, and process for their manufacture Expired EP0019087B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT80101985T ATE4227T1 (en) 1979-05-14 1980-04-14 DESULPHURIZING AGENT FOR PIG IRON AND STEEL MELT AND A PROCESS FOR THEIR MANUFACTURE.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE2919324 1979-05-14
DE19792919324 DE2919324A1 (en) 1979-05-14 1979-05-14 DEHANIZER FOR RAW IRON AND STEEL MELTING AND A METHOD FOR THE PRODUCTION THEREOF

Publications (2)

Publication Number Publication Date
EP0019087A1 EP0019087A1 (en) 1980-11-26
EP0019087B1 true EP0019087B1 (en) 1983-07-20

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EP80101985A Expired EP0019087B1 (en) 1979-05-14 1980-04-14 Desulphurising agents for pig iron and steel melts, and process for their manufacture

Country Status (9)

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US (1) US4323392A (en)
EP (1) EP0019087B1 (en)
JP (1) JPS55158212A (en)
AT (1) ATE4227T1 (en)
CA (1) CA1141964A (en)
DE (2) DE2919324A1 (en)
ES (1) ES491528A0 (en)
NO (1) NO153108C (en)
ZA (1) ZA802836B (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0061012A1 (en) * 1981-03-24 1982-09-29 Hoechst Aktiengesellschaft Process for producing desulfurizing agents for pig iron and steel melts
EP0061011A1 (en) * 1981-03-24 1982-09-29 Hoechst Aktiengesellschaft Process for producing desulfurizing agents for pig iron or steel melts
EP0387580A1 (en) * 1989-03-13 1990-09-19 Hoechst Aktiengesellschaft Agent and method for desulfurizing molten metals

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2920353A1 (en) * 1979-05-19 1980-11-27 Hoechst Ag METHOD FOR THE PRODUCTION OF DEHANIZING AGENTS FOR CRUDE IRON OR STEEL MELT
DE2952686A1 (en) * 1979-12-29 1981-07-02 Hoechst Ag, 6230 Frankfurt METHOD FOR THE PRODUCTION OF DESULFURING AGENTS FOR BOD IRON OR STEEL MELT
ES497686A0 (en) * 1979-12-29 1981-11-01 Hoechst Ag PROCEDURE FOR THE PREPARATION OF AN AGENT FOR THE DE-SULFURATION OF METALLIC CAST MASSES

Citations (2)

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Publication number Priority date Publication date Assignee Title
DE1935567B2 (en) * 1969-07-12 1971-05-13 Knapsack AG, 5033 Hurth Knapsack PROCESS FOR THE PRODUCTION OF CALCIUM CARBIDE OF CERTAIN QUALITY
DE1919414B2 (en) * 1969-04-17 1977-07-14 Hoechst Ag, 6000 Frankfurt METHOD AND DEVICE FOR COOLING CALCIUM CARBIDE PICKED IN VESSELS

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US3666445A (en) * 1967-12-26 1972-05-30 Kaiser Ind Corp Auxiliary composition for steel-making furnaces
DE1758250B1 (en) * 1968-04-29 1971-10-28 Sueddeutsche Kalkstickstoff Agent for the desulphurisation of iron melts
DE2037758C3 (en) * 1970-07-30 1979-08-02 Hoechst Ag, 6000 Frankfurt Process for the production of calcium carbide for the desulfurization of metal melts
JPS554811B2 (en) * 1973-06-13 1980-02-01
DE2741588C2 (en) * 1977-09-15 1985-02-07 Skw Trostberg Ag, 8223 Trostberg Agent for desulphurising molten iron

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1919414B2 (en) * 1969-04-17 1977-07-14 Hoechst Ag, 6000 Frankfurt METHOD AND DEVICE FOR COOLING CALCIUM CARBIDE PICKED IN VESSELS
DE1935567B2 (en) * 1969-07-12 1971-05-13 Knapsack AG, 5033 Hurth Knapsack PROCESS FOR THE PRODUCTION OF CALCIUM CARBIDE OF CERTAIN QUALITY

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0061012A1 (en) * 1981-03-24 1982-09-29 Hoechst Aktiengesellschaft Process for producing desulfurizing agents for pig iron and steel melts
EP0061011A1 (en) * 1981-03-24 1982-09-29 Hoechst Aktiengesellschaft Process for producing desulfurizing agents for pig iron or steel melts
EP0387580A1 (en) * 1989-03-13 1990-09-19 Hoechst Aktiengesellschaft Agent and method for desulfurizing molten metals

Also Published As

Publication number Publication date
JPS55158212A (en) 1980-12-09
US4323392A (en) 1982-04-06
ZA802836B (en) 1981-06-24
ATE4227T1 (en) 1983-08-15
ES8101121A1 (en) 1980-12-16
JPS6353244B2 (en) 1988-10-21
CA1141964A (en) 1983-03-01
NO153108C (en) 1986-01-15
NO153108B (en) 1985-10-07
ES491528A0 (en) 1980-12-16
EP0019087A1 (en) 1980-11-26
DE3064206D1 (en) 1983-08-25
DE2919324A1 (en) 1980-12-04
NO801420L (en) 1980-11-17

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