[go: up one dir, main page]

EP0061012A1 - Process for producing desulfurizing agents for pig iron and steel melts - Google Patents

Process for producing desulfurizing agents for pig iron and steel melts Download PDF

Info

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)
French (fr)
Other versions
EP0061012B1 (en
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/en
Publication of EP0061012A1 publication Critical patent/EP0061012A1/en
Application granted granted Critical
Publication of EP0061012B1 publication Critical patent/EP0061012B1/en
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
    • 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)

Abstract

The disclosure provides mixtures for the desulfurization of metal melts, especially steel and crude iron melts, based on CaC2-CaO-crystal blends produced in the fused mass. More specifically, the mixtures contain free carbon and carbonate and have a portion of the CaO in the CaC2-CaO-crystal blend hydrated to Ca(OH)2. The disclosure also relates to a process for making the mixtures.

Description

Die Erfindung betrifft ein Gemisch zum Entschwefeln von Metallschmelzen, insbesondere von Stahl- und Roheisenschmelzen, auf der Basis von im Schmelzfluß gewonnenen CaC2-CaO-Kristallgemengen sowie ein Verfahren zur Herstellung des Gemisches.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.

Die DE-OS 29 07 069 beschreibt bereits ein Mittel zur Entschwefelung von Metallschmelzen, insbesondere von Roheisen und Stahl, auf der Basis CaC2/CaO, welches aus einem im Schmelzfluß hergestellten und anschließend zerkleinerten CaC2/CaO-Kristallgemenge mit einem CaC2-Anteil von 35 bis 65 Gew%, bezogen auf die CaC2/CaO-Menge, besteht. Es ist weiterhin Stand der Technik, Metallschmelzen mit technischem Carbid (ca. 80 Gew% CaC2, Rest Ca0) oder auch mit Mischungen von technischem Carbid mit Zusätzen an Kohlenstoff und gasabspaltenden Stoffen, z.B. Ca(OH)2, zu entschwefeln (DE-AS 22 52 795). Um einen guten Ausnutzungsgrad zu bekommen, hat man die bekannten Entschwefelungsgemische, insbesondere für den Einsatz nach dem Tauchlanzenverfahren, zunächst möglichst feinkörnig mahlen müssen. Danach entsprechen diese Gemische zwar den gestellten Anforderungen, sind jedoch sowohl bezüglich Herstellung als auch Eomsatz teuer. Trotz der Feinmahlung mußten zur Erzielung des gewünschten Entschwefelungsgrades verhältnismäßig große Mengen der Entschwefelungsgemische zugesetzt werden.DE-OS 29 07 069 already describes an agent for the desulfurization of molten metals, in particular pig iron and steel, based on CaC 2 / CaO, which consists of a CaC 2 / CaO crystal mixture produced in the melt flow and subsequently comminuted with a CaC 2 - Share of 35 to 65 wt%, based on the amount of CaC 2 / CaO, exists. It is also state of the art to desulfurize metal melts with technical carbide (approx. 80% by weight CaC 2 , remainder Ca0) or also with mixtures of technical carbide with additions of carbon and gas-releasing substances, eg Ca (OH) 2 (DE- AS 22 52 795). In order to get a good degree of utilization, 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.

Aufgabe der vorliegenden Erfindung ist es daher, ein Entschwefelungsgemisch zu schaffen, das einen besseren Ausnutzungsgrad bietet, und ein wirtschaftliches Verfahren zur Herstellung dieses Gemisches bereitzustellen.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.

Es wird daher erfindungsgemäß vorgeschlagen, daß die Gemische freien Kohlenstoff und Carbonat enthalten und im CaC2-CaO-Kristallgemenge ein Teil des CaO zu Ca(OH)2 hydratisiert ist. Hierbei geht man vorzugsweise von CaC2-CaO-Kristallgemengen mit einem Anteil von 40 bis 80 Gew% Ca0 (entsprechend 20 bis 60 Gew% CaC2), insbesondere 45 bis 80 Gew% Ca0 (entsprechend 20 bis 55 Gew% CaC2) oder 40 bis 65 Gew% Ca0 (entsprechend 35 bis 60 Gew% CaC2) aus. Das erfindungsgemäße Gemisch ist weiterhin bevorzugt dadurch gekennzeichnet, daß es 1 bis 6 Gew%, vorzugsweise 2,5 bis 3,5 Gew%, von an Calciumoxid chemisch gebundenem Wasser enthält. Die Gemische der Erfindung enthalten neben dem im Schmelzfluß gewonnenen CaC2-CaO-Kristallgemenge bevorzugt 0,5 bis 8 Gew% freien Kohlenstoff (z.B. Koksgrus, Anthrazit, Graphit, Ruß) und 0,5 bis 20 Gew% Carbonate des Calciums, Magnesiums oder Natriums.It is therefore proposed according to the invention that 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. In addition to the CaC 2 -CaO crystal mixture obtained in the melt flow, 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.

Beim Erstarren aus dem Schmelzfluß kristallisieren Ca0 und CaC2 als Kristallgemenge, in dem die CaC2- und CaO-Kristalle ineinander verwachsen vorliegen, und zwar bei dem angegebenen CaC2/CaO-Mengenverhältnis mit einer im Bereich des Eutektikums liegenden bzw. zur Kalkseite verschobenen untereutektischen Zusammensetzung. Beim Zusatz von H20 reagiert ein Teil des Ca0 im Kristallgemenge nach der Gleichung

Figure imgb0001
ohne daß das mit den CaO-Kristallen verwachsene CaC2 wesentlich vom H20 angegriffen wird.When solidifying from the melt flow, 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. When H 2 0 is added, part of the Ca0 in the crystal mixture reacts according to the equation
Figure imgb0001
 without the CaC 2 grown together with the CaO crystals being substantially attacked by the H 2 0.

Wenn ein solches Entschwefelungsgemisch in eine Metallschmelze eingeblasen wird, so zerfallen die Mahlkörner, die aus CaO-CaC2-Kristallverwachsungen bestehen, in denen ein Teil der CaO-Kristalle hydratisiert ist, bei den herrschenden Temperaturen oberhalb 800°C nach folgender Reaktionsgleichung

Figure imgb0002
If such a desulfurization mixture is blown into a molten metal, 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
Figure imgb0002

Wegen der Gasentwicklung an den reaktiven Kristallgrenzflächen zerplatzt das Mahlkorn regelrecht unter Freisetzung von in statu nascendi hochreaktivem Kalk und unter Vergrößerung der im Korn verwachsenen CaO-CaC2-Kristalloberflächen. Bei nahezu eutektischem Kristallaufbau ergibt sich eine ideal große Reaktionsoberfläche. Die freiwerdenden reduzierend wirkenden Gase bieten.dabei ideale Voraussetzungen für eine Umsetzung des Ca0 mit dem in der Metallschmelze gelösten Schwefel.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.

Ein solches Entschwefelungsgemisch eignet sich insbesondere hervorragend bei Entschwefelungsprozessen, bei denen die Zeit für den Umsatz des Entschwefelungsgemischs mit dem Schwefel sehr kurz ist. Zu diesem Verfahren gehört das Tauchlanzenverfahren, bei dem durch Einblasen von Entschwefelungsgemischen in eine Metallschmelze unterhalb deren Oberfläche in der kurzen Zeit vom Austritt des Entschwefelungsgemisches in die Schmelze bis zum Aufsteigen an die Badoberfläche die Umsetzung des Entschwefelungsgemisches möglichst vollständig erfolgen sollte.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.

Das erfindungsgemäße Entschwefelungsgemisch zeigt sich den besten bekannten Gemischen auf Carbidbasis in der Entschwefelungswirkung überlegen. Wegen der interkristallinen Gasreaktion im Mahlkorn ist die Umsetzung von CaC2 zu Ca0 und die dadurch bedingte Vergrößerung der Kristalloberflächen wirkungsvoller, die Gasentwicklung viel gleichmäßiger und weniger heftig als bei bekannten Entschwefelungsgemischen, z.B. gemäß DE-AS 22 52 795, denen gasabspaltende Zusätze mechanisch untergemengt sind. Die Entschwefelung erfolgt deshalb insbesondere in der offenen Pfanne und der Torpedopfanne ruhiger und mit geringeren Metallauswürfen. Wegen der höheren Reaktivität des erfindungsgemäßen Entschwefelungsgemisches als Folge der Vergrößerung der Kristalloberflächen beim Zerplatzen des Mahlkorns in der Schmelze kann das Material grobkörniger eingesetzt werden, so daß teures Feinmahlen entfallen kann.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. Because of the higher reactivity of the desulfurization mixture according to the invention as a result of the enlargement of the crystal surfaces when the grinding grain bursts in the melt, the material can be used in a coarser manner, so that expensive fine grinding can be dispensed with.

Die Verwendung des erfindungsgemäßen Entschwefelungsgemisches ermöglicht wegen seiner homogenen Zusammensetzung eine größere Treffsicherheit auf den jeweils geforderten Endgehalt. Die Herstellungskosten für das erfindungsgemäße Gemisch liegen erheblich niedriger als für bekannte Mittel auf Carbidbasis.Due to its homogeneous composition, 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.

Weiterhin wird ein Verfahren zur Herstellung des erfindungsgemäßen Gemisches vorgeschlagen, welches dadurch gekennzeichnet ist, daß man in eine in üblicher Weise erzeugte Calciumcarbidschmelze, welche bereits einen Calciumoxidgehalt bis zu 45 Gew% aufweist, feinteiliges Calciumoxid einträgt, in einem Überschuß von 3 bis 15 Gew%, bezogen auf die im CaC2-CaO-Kristallgemenge gewünschte Menge, dann die erhaltene Mischung unter Erstarren auf Temperaturen von 350 bis 450°C abkühlt, bei diesen Temperaturen auf Korngrößen kleiner als 150 mm vorbricht, den dabei zwangsläufig anfallenden Kornanteil kleiner als 4 mm vom verbleibenden Produkt abtrennt, letzterem freien Kohlenstoff und Carbonat zumischt und das Gemisch in Gegenwart von Luft oder Stickstoff mit einem Feuchtigkeitsgehalt von 5 bis 20 g/m3 (bei 1,013 bar und 273,15 K) durch Brechen und Mahlen bei Temperaturen unterhalb 100°C, vorzugsweise von 10 - 50°C, auf Korngrößen kleiner als 10 mm, vorzugsweise kleiner als 0,1 mm, zerkleinert.Furthermore, 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. , based on the amount desired in the CaC 2 -CaO crystal mixture, then cools the resulting mixture under solidification to temperatures of 350 to 450 ° C, at these temperatures breaks down to grain sizes less than 150 mm, the grain fraction inevitably obtained is less than 4 mm separated from the remaining product, the latter mixed free carbon and carbonate and the mixture in the presence of air or nitrogen with a moisture content of 5 to 20 g / m 3 (at 1.013 bar and 273.15 K) by breaking and grinding at temperatures below 100 ° C, preferably from 10-50 ° C, crushed to grain sizes smaller than 10 mm, preferably smaller than 0.1 mm.

Wahlweise und bevorzugt ist dieses Herstellungsverfahren dadurch gekennzeichnet, daß

  • a) die Zugabe des Calciumoxids, die sogenannte Magerung des Carbids, unter Ausnutzung des Wärneinhaltes des Carbids in einem Tiegel durchgeführt wird,
  • b) man das Calciumoxid, welches in die Calciumcarbidschmelze eingetragen wird, auf Temperaturen bis zu 20000C vorerhitzt und heiß in die Schmelze einbringt, wobei die Vorerhitzung um so höher gewählt wird, je höher der gewünschte Anteil an zusätzlich gelöstem Calciumoxid zwischen 40 und 80 Gew% liegen soll,
  • c) von einer Calciumcarbidschmelze ausgegangen wird, welche zwischen 20 und 45 Gew% Calciumoxid enthält,
  • d) man die nach dem Vorbrechen abgesiebten Anteile kleiner als 4 mm in den Prozeß zurückführt.
This manufacturing process is optionally and preferably characterized in that
  • a) the addition of the calcium oxide, the so-called thinning of the carbide, is carried out using the heat content of the carbide in a crucible,
  • b) contacting the calcium oxide which is added to the Calciumcarbidschmelze, up to 2000 0 C preheated to temperatures and hot in the melt is introduced, wherein the preheating is selected to be higher, the higher the desired proportion of additionally dissolved calcium oxide between 40 and 80 % By weight should be
  • c) a calcium carbide melt is assumed which contains between 20 and 45% by weight calcium oxide,
  • d) the portions smaller than 4 mm which have been screened off after preliminary crushing are returned to the process.

Wenn das Calciumoxid, welches in die Schmelze eingetragen wird, vorher auf Temperaturen bis zu 2000°C, vorzugsweise bis zu 1100°C, vorerhitzt und mit diesen Temperaturen heiß in die Schmelze eingebracht wird, so ist es möglich, den Ca0-Gehalt im Carbid bis auf 80 Gew% zu erhöhen, wobei die Vorerhitzung um so höher gewählt wird, je höher der gewünschte Anteil an zusätzlich gelöstem Calciumoxid zwischen 40 und 80 Gew% liegen soll. Dadurch wird die Anwendung in kohlenstoffarmen Roheisen- und Stahlschmelzen ermöglicht und außerdem die Entschwefelungsausbeute, bezogen auf Calciumcarbid, erhöht.If 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.

Die nach dem Vorbrechen abgesiebten Anteile kleiner als 4 mm bestehen im wesentlichen aus Ca0 und können als feinteiliges Calciumoxid wieder in den Prozeß zurückgeführt werden, wo sie zusammen mit frischem Ca0 als Ausgangsprodukt dienen. Nicht vorhersehbar war für den Fachmann, daß durch das Absieben der nach dem Vorbrechen abfallenden Anteile kleiner als 4 mm aus dem Produkt die Anteile entfernt werden, welche keine oder nur eine geringe Entschwefelungswirkung besitzen, und so die Wirksamkeit des Endproduktes erheblich gesteigert wird.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.

Das erfindungsgemäß hergestellte Produkt läßt sich wesentlich besser mahlen als nach bekannten Verfahren erhaltene Produkte. Dies ist deshalb von besonderer Wichtigkeit, weil das Produkt in manchen Fällen mit einer Körnung kleiner als 0,1 mm eingesetzt werden muß.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.

Anhand der folgenden Beispiele wird die Erfindung näher erläutert:The invention is explained in more detail using the following examples:

Beispiel 1example 1

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 Ca0-Gehalt von ca. 40 Gew% entspricht. In den Strahl des aus dem Ofen in einen Tiegel abgestochenen schmelzflüssigen Carbides wird Ca0 mit einer Körnung von 3 bis 8 mm und einem Ca(OH)2- und CaC03-Gehalt von jeweils weniger als 1 Gew% mit einer solchen Geschwindigkeit und in solchen Mengen eingetragen, daß, bis der Tiegel gefüllt ist, insgesamt ein CaC2 : CaO-Gewichtsverhältnis von 43 : 57 vorliegt, was einem Überschuß von 14 Gew% CaO, bezogen auf den im CaC2-CaO-Kristallgemenge gewünschten Ca0-Gehalt von 50 Gew%, entspricht. Dann wird abgekühlt, bis die Durchschnittstemperatur des dabei erstarrten Carbidblokkes etwa 400°C beträgt, und der Block auf Größen kleiner als 150 mm vorgebrochen.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.

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 Kristallgemenge von 50 Gew% CaC2 und 50 Gew% Ca0 darstellt. 850 kg dieses CaC2-CaO-Kristallgemenges werden mit 100 kg Kalkstein (Körnung kleiner 1 mm) und 50 kg Koksgrus (Körnung kleiner 3 mm) vermischt und unter Durchleiten von 1500 m3/h Luft mit einem Feuchtigkeitsgehalt von 10 g/m3 (bei 15°C) in einer Rotationsmühle mit einem Durchsatz von 500 kg/h bei 50°C auf Korngrößen kleiner als 0,1 mm gemahlen. Die abgesiebte Kornfraktion kleiner als 4 mm wird zusammen mit frischem Kalk (Ca0) wieder als Ausgangsprodukt eingesetzt. Das erhaltene Produkt enthält 2 Gew% chemisch gebundenes Wasser.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.

Durch Einblasen von 1500 kg dieses Produktes in eine 300 t-Roheisenschmelze mit einem Schwefelgehalt von 0,03 Gew% bei Temperaturen von 1400°C wird der Schwefelgehalt der Eisenschmelze auf weniger als 0,005 Gew% gesenkt.By blowing 1500 kg of this product into a 300 t pig iron melt with a sulfur content of 0.03% by weight at temperatures of 1400 ° C, the sulfur content of the iron melt is reduced to less than 0.005% by weight.

Beispiel 2Example 2

Es wird wie im Beispiel 1 verfahren, mit den Änderungen, daß das Ca0 vor dem Eintragen auf eine Temperatur von etwa 1100°C vorerhitzt und die Menge an Ca0 so erhöht wird, daß sich insgesamt im Tiegel ein Ca0-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.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 des erfindungsgemäß aufgearbeiteten und gemahlenen Produktes werden zur Entschwefelung einer 300 t-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 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.

Beispiel 3Example 3

a) Eine 300 t-Roheisenschmelze mit folgender Analyse (Gew%):

  • 4,5 % Kohlenstoff, 0,8 % Silizium, 0,7 % Mangan, 0,08 % Phosphor, 0,064 % Schwefel, Rest Eisen wurde nach dem Tauchlanzenverfahren mit dem erfindungsgemäßen Entschwefelungsgemisch aus Beispiel 1 in einer offenen Pfanne entschwefelt. Die Tauchtiefe der Lanze betrug 1,8 m. Die Einblasgeschwindigkeit betrug 100 kg/min. Der Gesamtverbrauch des Entschwefelungsgemisches betrug 4,5 kg/t, mit dem der Schwefelgehalt auf 0,009 Gew% gesenkt wurde. Das entspricht einem Entschwefelungsgrad von 86 %.
a) A 300 t pig iron melt with the following analysis (% by weight):
  • 4.5% carbon, 0.8% silicon, 0.7% manganese, 0.08% phosphorus, 0.064% sulfur, the remainder iron was desulphurized in an open pan by the immersion lance method with the desulfurization mixture according to the invention from Example 1. The depth of the lance was 1.8 m. The blowing speed was 100 kg / min. The total consumption of the desulfurization mixture was 4.5 kg / t, with which the sulfur content was reduced to 0.009% by weight. This corresponds to a degree of desulfurization of 86%.

b) Bei einem Vergleichsversuch mit einem zum Stand der Technik gehörenden Gemisch, bestehend aus 85 Gew% technischem Carbid (78 Gew% CaC2-Gehalt) und 15 Gew% CaC03 benötigte man mit der gleichen Tauchtiefe und Einblasgeschwindigkeit wie unter 3 a) 6,0 kg/t, um bei gleichem Schwefelausgangsgehalt denselben Entschwefelungsgrad zu erreichen.b) In a comparative test with a mixture belonging to the prior art, consisting of 85% by weight technical carbide (78% by weight CaC 2 content) and 15% by weight CaC0 3 , the same immersion depth and blowing rate as under 3 a) 6 were required .0 kg / t in order to achieve the same desulfurization level with the same initial sulfur content.

Bei dem erfindungsgemäßen Entschwefelungsgemisch ergibt sich gegenüber dem bei diesem Vergleichsversuch benutzten bekannten Entschwefelungsgemisch eine Ersparnis von 25 %, bezogen auf die absolute Menge an Entschwefelungsgemisch, und eine Ersparnis von 45 %, bezogen auf den CaC2-Anteil. Im selben Maß verkürzt sich auch die Behandlungszeit.In the desulfurization mixture according to the invention, compared to the known desulfurization mixture used in this comparative test, there is a saving of 25%, based on the absolute amount of desulfurization mixture, and a saving of 45%, based on the CaC 2 content. The treatment time is shortened to the same extent.

Claims (8)

1. Gemisch zum Entschwefeln von Metallschmelzen, insbesondere von Stahl- und Roheisenschmelzen, auf der Basis von im Schmelzfluß gewonnenen CaC2-CaO-Kristallgemen- gen, dadurch gekennzeichnet, daß es freien Kohlenstoff und Carbonat enthält und im CaC2-CaO-Kristallgemenge ein Teil des Ca0 zu Ca(OH)2 hydratisiert ist.1. Mixture for desulfurizing metal melts, in particular steel and pig iron melts, based on CaC 2 -CaO crystal mixtures obtained in the melt flow, characterized in that it contains free carbon and carbonate and in the CaC 2 -CaO crystal mixture Part of the Ca0 is hydrated to Ca (OH) 2 . 2. Gemisch nach Anspruch 1, ausgehend von einem CaC2-CaO-Kristallgemenge mit einem Anteil von 40 bis 80 Gew% CaO.2. Mixture according to claim 1, starting from a CaC 2 -CaO crystal mixture with a proportion of 40 to 80% by weight of CaO. 3. Gemisch nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß es 1 bis 6 Gew%, vorzugsweise 2,5 bis 3,5 Gew%, von an Calciumoxid chemisch gebundenem Wasser enthält.3. Mixture according to claim 1 or 2, 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. 4. Gemisch nach einem der Ansprüche 1 - 3, dadurch gekennzeichnet, daß es 0,5 bis 8 Gew% freien Kohlenstoff und 0,5 bis 20 Gew% Carbonate des Calciums, Magnesiums oder Natriums enthält.4. Mixture according to one of claims 1-3, characterized in that it contains 0.5 to 8% by weight of free carbon and 0.5 to 20% by weight of carbonates of calcium, magnesium or sodium. 5. Verfahren zur Herstellung eines Gemisches nach einem der Ansprüche 1 - 4, dadurch gekennzeichnet, daß man in eine in üblicher Weise erzeugte Calciumcarbidschmelze, welche bereits einen Calciumoxidgehalt bis zu 45 Gew% aufweist, feinteiliges Calciumoxid einträgt, in einem Überschuß von 3 bis 15 Gew%, bezogen auf die im Cac2-CaO-Kristallgemenge gewünschte Menge, dann die erhaltene Mischung unter Erstarren auf Temperaturen von 350 bis 450°C abkühlt, bei diesen Temperaturen auf Korngrößen kleiner als 150 mm vorbricht, den dabei zwangsläufig anfallenden Kornanteil kleiner als 4 mm vom verbleibenden Produkt abtrennt, letzterem freien Kohlenstoff und Carbonat zumischt und das Gemisch in Gegenwart von Luft oder Stickstoff mit einem Feuchtigkeitsgehalt von 5 bis 20 g/m3 (bei 1,013 bar und 273,15 K) durch Brechen und Mahlen bei Temperaturen unterhalb 100°C, vorzugsweise 10 - 50°C, auf Korngrößen kleiner als 10 mm, vorzugsweise kleiner als 0,1 mm, zerkleinert.5. A process for the preparation of a mixture according to any one of claims 1-4, characterized in that in a calcium carbide melt produced in a conventional manner, which already has a calcium oxide content of up to 45% by weight, finely divided calcium oxide is introduced into an excess of 3 to 15% by weight, based on the amount desired in the Cac 2 -CaO crystal mixture, then cools the resulting mixture under solidification to temperatures of 350 to 450 ° C, at these temperatures breaks down to grain sizes smaller than 150 mm inevitably separating the grain fraction smaller than 4 mm from the remaining product, adding free carbon and carbonate to the latter and mixing the mixture in the presence of air or nitrogen with a moisture content of 5 to 20 g / m 3 (at 1.013 bar and 273.15 K) Crushing and grinding at temperatures below 100 ° C., preferably 10-50 ° C., to particle sizes smaller than 10 mm, preferably smaller than 0.1 mm. 6. Verfahren nach Anspruch 5, dadurch gekennzeichnet, daß man das Calciumoxid, welches in die Calciumcarbidschmelze eingetragen wird, auf Temperaturen bis zu 2000°C vorerhitzt und heiß in die Schmelze einbringt, wobei die Vorerhitzung um so höher gewählt wird, je höher der gewünschte Anteil an zusätzlich gelöstem Calciumoxid zwischen 40 und 80 Gew% liegen soll.6. The method according to claim 5, characterized in that the calcium oxide, which is introduced into the calcium carbide melt, preheated to temperatures up to 2000 ° C and introduced hot into the melt, the preheating being chosen the higher, the higher the desired The proportion of additionally dissolved calcium oxide should be between 40 and 80% by weight. 7. Verfahren nach Anspruch 5 oder 6, dadurch gekennzeichnet, daß von einer Calciumcarbidschmelze ausgegangen wird, welche zwischen 20 und 45 Gew% Calciumoxid enthält.7. The method according to claim 5 or 6, characterized in that a calcium carbide melt is assumed which contains between 20 and 45% by weight calcium oxide. 8. Verfahren nach einem der Ansprüche 5 bis 7, dadurch gekennzeichnet, daß man die nach dem Vorbrechen abgesiebten Anteile kleiner als 4 mm in den Prozeß zurückführt.8. The method according to any one of claims 5 to 7, characterized in that the portions sieved after the preliminary crushing less than 4 mm are returned to the process.
EP82101428A 1981-03-24 1982-02-25 Process for producing desulfurizing agents for pig iron and steel melts Expired EP0061012B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT82101428T ATE9232T1 (en) 1981-03-24 1982-02-25 PROCESS FOR THE MANUFACTURE OF A DESULPHURIZING AGENT FOR MELTED PIG IRON AND STEEL.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3111510 1981-03-24
DE19813111510 DE3111510A1 (en) 1981-03-24 1981-03-24 DESULFURATION MIXTURE AND METHOD FOR THE PRODUCTION THEREOF

Publications (2)

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

Family

ID=6128140

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82101428A Expired EP0061012B1 (en) 1981-03-24 1982-02-25 Process for producing desulfurizing agents for pig iron and steel melts

Country Status (10)

Country Link
US (1) US4395282A (en)
EP (1) EP0061012B1 (en)
JP (1) JPS57171611A (en)
AT (1) ATE9232T1 (en)
BR (1) BR8201621A (en)
CA (1) CA1184385A (en)
DD (1) DD202182A5 (en)
DE (2) DE3111510A1 (en)
ES (1) ES510768A0 (en)
ZA (1) ZA821940B (en)

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 (en) * 1984-05-16 1988-08-23 Heinrich Rellermeyer Method, process and composition for desulfurizing pig-iron melts
BR8606249A (en) * 1985-12-17 1987-09-29 Sueddeutsche Kalkstickstoff FINALLY GRANULATED COMPOSITION FOR THE DESULFURATION OF CAST IRON AND PROCESS FOR ITS PREPARATION
DE3908071A1 (en) * 1989-03-13 1990-09-20 Hoechst Ag MEANS AND METHOD FOR DISCHARGING METAL MELTS
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 (en) * 1994-12-09 2000-07-25 Donau Chemie Ag AGENT FOR TREATING RAW IRON AND CAST IRON MELT FOR THE PURPOSE OF DESULFURATION
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 (en) * 1973-05-24 1974-12-12 Sueddeutsche Kalkstickstoff PROCESS FOR THE PREPARATION OF HYDROGEN MIXTURES BASED ON CALCIUM CARBIDE FOR DESULFURIZING METAL MELT
DE2252795B2 (en) * 1972-10-27 1977-02-03 Süddeutsche Kalkstickstoff-Werke AG, 8223 Trostberg DESULFURIZING AGENT FOR METAL MELTING WITH WATER-RELEASING ADDITIVE
DE2741588A1 (en) * 1977-09-15 1979-03-29 Sueddeutsche Kalkstickstoff AGENT FOR DESULFURIZING FELT IRON
DE2907069A1 (en) * 1979-02-23 1980-08-28 Krupp Ag Huettenwerke Ferrous melt desulphurising compsn. - is made from calcium carbide and calcium oxide, subsequently crystallised and then comminuted
EP0019086A2 (en) * 1979-05-19 1980-11-26 Hoechst Aktiengesellschaft Process for producing desulfurizing agents for pig iron or steel melts
EP0031552A1 (en) * 1979-12-29 1981-07-08 Hoechst Aktiengesellschaft Desulphurising composition and process for its production
EP0031534A1 (en) * 1979-12-29 1981-07-08 Hoechst Aktiengesellschaft Process for producing desulfurizing agents for pig iron or steel melts
EP0019087B1 (en) * 1979-05-14 1983-07-20 Hoechst Aktiengesellschaft Desulphurising agents for pig iron and steel melts, and process for their manufacture

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH428820A (en) * 1963-12-12 1967-01-31 Tech Entwicklung Und Verwertun Steel refining product
US3197306A (en) * 1964-08-31 1965-07-27 Dow Chemical Co Method for treating ferrous metals
DE1758250B1 (en) * 1968-04-29 1971-10-28 Sueddeutsche Kalkstickstoff Agent for the desulphurisation of iron melts

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2252795B2 (en) * 1972-10-27 1977-02-03 Süddeutsche Kalkstickstoff-Werke AG, 8223 Trostberg DESULFURIZING AGENT FOR METAL MELTING WITH WATER-RELEASING ADDITIVE
DE2326539A1 (en) * 1973-05-24 1974-12-12 Sueddeutsche Kalkstickstoff PROCESS FOR THE PREPARATION OF HYDROGEN MIXTURES BASED ON CALCIUM CARBIDE FOR DESULFURIZING METAL MELT
DE2741588A1 (en) * 1977-09-15 1979-03-29 Sueddeutsche Kalkstickstoff AGENT FOR DESULFURIZING FELT IRON
DE2907069A1 (en) * 1979-02-23 1980-08-28 Krupp Ag Huettenwerke Ferrous melt desulphurising compsn. - is made from calcium carbide and calcium oxide, subsequently crystallised and then comminuted
EP0019087B1 (en) * 1979-05-14 1983-07-20 Hoechst Aktiengesellschaft Desulphurising agents for pig iron and steel melts, and process for their manufacture
EP0019086A2 (en) * 1979-05-19 1980-11-26 Hoechst Aktiengesellschaft Process for producing desulfurizing agents for pig iron or steel melts
EP0031552A1 (en) * 1979-12-29 1981-07-08 Hoechst Aktiengesellschaft Desulphurising composition and process for its production
EP0031534A1 (en) * 1979-12-29 1981-07-08 Hoechst Aktiengesellschaft Process for producing desulfurizing agents for pig iron or steel melts

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

Similar Documents

Publication Publication Date Title
EP0061012B1 (en) Process for producing desulfurizing agents for pig iron and steel melts
EP0031552B1 (en) Desulphurising composition and process for its production
EP0220522B1 (en) Mixture for desulfurizing metal melts, process for manufacturing it and its use
EP0019086B1 (en) Process for producing desulfurizing agents for pig iron or steel melts
DE2037758C3 (en) Process for the production of calcium carbide for the desulfurization of metal melts
EP0019087B1 (en) Desulphurising agents for pig iron and steel melts, and process for their manufacture
EP0031534B1 (en) Process for producing desulfurizing agents for pig iron or steel melts
DE2709062A1 (en) MEANS AND METHODS FOR DESULFURIZING METAL IRON
DE2708424C2 (en) Process for desulfurization of pig iron melts
EP0582970A1 (en) Additive for desulfurization of liquid pig and cast iron and process for desulfurizing
DE2907069C3 (en) Agent for the desulfurization of metal melts
EP0061011B1 (en) Process for producing desulfurizing agents for pig iron or steel melts
DE2406845A1 (en) STEEL REFINING PROCESS
WO2016096178A1 (en) Mixture, use of said mixture and process for conditioning a slag located on a metal melt in a metallurgical vessel in iron and steel metallurgy
DE3008950C2 (en) Desulphurising agent and process for its preparation
DE3000927C2 (en) Desulfurization of ferrous metals
DE2236160A1 (en) Means for desulfurization of liquid iron and the process for its manufacture
DE3544562A1 (en) Finely granular agent for desulphurising iron melts
DE2048203B2 (en) Casting aids for use in casting metal
DE2952761A1 (en) Desulphurising of molten metals, esp. crude iron or steel - using mixed crystals of calcium carbide and calcium oxide which is partly hydrated
DE1433638A1 (en) Process for the production of pig iron with a low phosphorus content
DD233809A5 (en) POWDER-FORMAL CALCIUM-ALUMINATE AGENT AND METHOD FOR THE PRODUCTION THEREOF
DE1245400B (en) Process for the production of ferronickel and iron

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): AT BE CH DE FR GB IT LU NL SE

17P Request for examination filed

Effective date: 19821127

ITF It: translation for a ep patent filed
GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Designated state(s): AT BE CH DE FR GB IT LI LU NL SE

REF Corresponds to:

Ref document number: 9232

Country of ref document: AT

Date of ref document: 19840915

Kind code of ref document: T

REF Corresponds to:

Ref document number: 3260643

Country of ref document: DE

Date of ref document: 19841011

ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: CH

Payment date: 19900423

Year of fee payment: 9

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19910125

Year of fee payment: 10

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: SE

Payment date: 19910128

Year of fee payment: 10

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: LU

Payment date: 19910130

Year of fee payment: 10

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: BE

Payment date: 19910214

Year of fee payment: 10

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Effective date: 19910228

Ref country code: CH

Effective date: 19910228

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 19910228

Year of fee payment: 10

EPTA Lu: last paid annual fee
REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19920115

Year of fee payment: 11

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: AT

Payment date: 19920122

Year of fee payment: 11

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19920225

Ref country code: GB

Effective date: 19920225

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Effective date: 19920226

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BE

Effective date: 19920228

ITTA It: last paid annual fee
BERE Be: lapsed

Owner name: KRUPP STAHL A.G.

Effective date: 19920228

Owner name: HOECHST A.G.

Effective date: 19920228

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Effective date: 19920901

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee
GBPC Gb: european patent ceased through non-payment of renewal fee
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: AT

Effective date: 19930225

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Effective date: 19931029

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

EUG Se: european patent has lapsed

Ref document number: 82101428.9

Effective date: 19920904

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19980123

Year of fee payment: 17

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19991201