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EP0031534B1 - Process for producing desulfurizing agents for pig iron or steel melts - Google Patents

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

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Publication number
EP0031534B1
EP0031534B1 EP80107915A EP80107915A EP0031534B1 EP 0031534 B1 EP0031534 B1 EP 0031534B1 EP 80107915 A EP80107915 A EP 80107915A EP 80107915 A EP80107915 A EP 80107915A EP 0031534 B1 EP0031534 B1 EP 0031534B1
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EP
European Patent Office
Prior art keywords
mixture
weight
cao
calcium oxide
size
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.)
Expired
Application number
EP80107915A
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German (de)
French (fr)
Other versions
EP0031534A1 (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
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Krupp Stahl AG
Hoechst AG
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Publication date
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Priority to AT80107915T priority Critical patent/ATE9101T1/en
Publication of EP0031534A1 publication Critical patent/EP0031534A1/en
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Publication of EP0031534B1 publication Critical patent/EP0031534B1/en
Expired legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C1/00—Refining of pig-iron; Cast iron
    • C21C1/02—Dephosphorising or desulfurising
    • C21C1/025—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
    • 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

Definitions

  • the present invention relates to a process for the production of desulfurization agents based on calcium oxide-containing calcium carbide for pig iron or steel melts.
  • a calcium carbide-calcium oxide melt mixture with a CaO content of 20 to 80% by weight is first produced from lime and coke, which is allowed to solidify to form a block. While the solidified block still has an average temperature of more than 400 ° C, it is broken down to a grain size of less than 150 mm and calcium oxide is added to the crushed mixture, which is still at least 400 ° C, in such an amount that it can be found in the The resulting total CaO content corresponds to the desired CaO content in the end product.
  • the mixture is then ground with intensive mixing and exclusion of moisture at temperatures above 100 ° C to grain sizes smaller than 10 mm.
  • the finely divided lime was preferably introduced into the jet of carbide tapped from the furnace. Although the amount of lime that can be introduced into the molten carbide is limited and working with liquid carbide is associated with dangers, it was previously believed in specialist circles that this method could not be dispensed with because it was believed that only a mixture of CaC produced in the melt 2 and CaO are best suited for the desulfurization of metal melts.
  • Desulphurization agents based on calcium carbide which contain substances which release water at the temperature of the molten metal, are already known from DE-B2-22 52 795.
  • These agents which are mixtures of commercially available carbide with, for example, Ca (OHh as a water-releasing substance, have the disadvantage that they are mixtures produced by mechanical mixing, in which carbide particles are present separately from Ca (OH) 2 particles, which is the case when these products are used leads to a higher consumption, uneven and violent gas reactions and a large spread regarding the desulfurization effect, which makes a targeted use of these agents difficult.
  • the mixture is then mixed vigorously and 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) at temperatures below 100 ° C., preferably at 10-15 ° C. , ground to grain sizes less than 10 mm, preferably less than 100 1 1m.
  • a calcium carbide-calcium oxide starting melt mixture with a CaO content of 20 to 45% by weight which was obtained in a known manner from lime and coke in a thermal manner.
  • a calcium carbide-calcium oxide starting melt mixture with a CaO content of over 45 to 80% by weight is first produced by adding finely divided calcium oxide to an existing calcium carbide melt which has a calcium oxide content of up to 45% by weight to a CaO content of up to 80% by weight and only then solidify the whole into a block before breaking it at temperatures above 400 ° C.
  • the method according to the invention also has the further advantages, inter alia, that a certain Möller composition is not set in each case to produce the carbide melt, and that the lime does not previously have a specific grain size must be finely ground, but that it can be assumed that a carbide block whose CaC 2 : CaO weight ratio fluctuates within a very wide range, that is to say can be practically arbitrary, and the lime also in coarse-grained form, for example in a grain size between 8 and 60 mm, can be used.
  • a further advantage of the inventive agent prepared is that densely present on the surface of each grain Ca (OH) 2 addition CaC 2, is set very early and uniformly in motion whereby the desulfurizing reaction. As a result, ver Similar desulfurization results require smaller amounts of the desulfurization agent and enables more targeted results.
  • a carbide block of corresponding composition was produced in a crucible in a known manner by allowing this melt to cool. After the block had cooled to an average temperature of about 600 ° C, it was crushed to grain sizes smaller than 150 mm and the carbide, which was still 500 ° C, was covered with so much lime with a grain size of 8 to 60 mm that the resulting mixture contained a total CaO content of 50% by weight.
  • the mixture was then passed through to a particle size between 0 and 100 1 while 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 Ground 1m.
  • Calcium carbide is produced thermally from lime and coke in a known manner, the lime-coke mixture in the entire Möller being adjusted to a weight ratio of approximately 110:40, which corresponds to a carbide with a CaO content of approximately 45% by weight.
  • CaO with a grain size of 3-8 mm is added to the tapping jet of this carbide in such an amount that an average content of approx. 80% by weight CaO results in the tapping crucible (about 1.2-1.3 t CaO per tonne of tapping jet).
  • the block is pre-broken to a grain size of less than 150 mm and as much lime with a grain size of 8 to 60 mm is layered on the hot mixture that the average CaO content is 90% by weight.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Treatment Of Steel In Its Molten State (AREA)
  • Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
  • Carbon And Carbon Compounds (AREA)
  • Coating With Molten Metal (AREA)
  • Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)
  • Glass Compositions (AREA)
  • Manufacture And Refinement Of Metals (AREA)

Abstract

The present invention relates to a process for the manufacture of desulfurizing agents containing 1-6% by weight of chemically bonded water, based on calcium oxide-containing calcium carbide, for crude iron and steel melts. To this end, a molten mixture of calcium carbide and calcium oxide with a CaO content of 20 to 80% by weight is produced, which is allowed to solidify into a block. Next, the block which still has an average temperature of more than 400 DEG C., is rough-crushed to particles with a size of less than 150 mm and calcium oxide is added to the comminuted mixture, which still has a temperature of at least 400 DEG C., in accordance with the CaO content desired in the end product. The mixture is finally ground in the presence of air or nitrogen with a moisture content of from 5 to 20 g/m3 (at 1.013 bar and 273.15 K) at temperatures below 100 DEG C. to particles with a size of less than 10 mm.

Description

Die vorliegende Erfindung betrifft ein Verfahren zur Herstellung von Entschwefelungsmitteln auf Basis von Calciumoxid enthaltendem Calciumcarbid für Roheisen- oder Stahlschmelzen. Gemäss der nicht vorveröffentlichten EP-A2-0 019 086 wurde hierzu bereits vorgeschlagen, dass man zunächst aus Kalk und Koks ein Calciumcarbid-Calciumoxid-Schmelzgemisch mit einem CaO-Gehalt von 20 bis 80 Gew% erzeugt, welches man zu einem Block erstarren lässt. Während der erstarrte Block noch eine Durchschnittstemperatur von mehr als 400°C aufweist, bricht man diesen auf Korngrössen kleiner als 150 mm vor und gibt auf das zerkleinerte und noch mindestens 400°C heisse Gemisch Calciumoxid in einer solchen Menge auf, dass der sich in der Mischung ergebende Gesamtgehalt von CaO dem im Endprodukt gewünschten CaO-Gehalt entspricht. Anschliessend wird die Mischung unter intensiver Vermengung und Feuchtigkeitsausschluss bei Temperaturen oberhalb 100°C auf Korngrössen kleiner als 10 mm gemahlen.The present invention relates to a process for the production of desulfurization agents based on calcium oxide-containing calcium carbide for pig iron or steel melts. According to EP-A2-0 019 086, which has not been published beforehand, it has already been proposed in this regard that a calcium carbide-calcium oxide melt mixture with a CaO content of 20 to 80% by weight is first produced from lime and coke, which is allowed to solidify to form a block. While the solidified block still has an average temperature of more than 400 ° C, it is broken down to a grain size of less than 150 mm and calcium oxide is added to the crushed mixture, which is still at least 400 ° C, in such an amount that it can be found in the The resulting total CaO content corresponds to the desired CaO content in the end product. The mixture is then ground with intensive mixing and exclusion of moisture at temperatures above 100 ° C to grain sizes smaller than 10 mm.

Allgemein ist bekannt, Roheisen- und Stahlschmelzen mit Hilfe von Calciumoxid (nachfolgend kurz als Kalk bezeichnet) enthaltendem Calciumcarbid (nachfolgend Carbid genannt) zu entschwefeln (DE-C 1 160 457, DE-C3-20 37 758). Bei der Herstellung solcher Entschwefelungsmittel ging man in der Regel bislang so vor, dass man in schmelzflüssiges Carbid die erforderliche Menge an feinteiligem Kalk eintrug, um in der Schmelze eine homogene Mischung zu erzeugen, die man anschliessend abkühlen liess und zerkleinerte.It is generally known to desulfurize pig iron and steel melts with the aid of calcium carbide (hereinafter referred to as lime) containing calcium oxide (hereinafter referred to as lime) (DE-C 1 160 457, DE-C3-20 37 758). In the production of such desulfurizing agents, the usual procedure so far was to add the required amount of finely divided lime to the molten carbide in order to produce a homogeneous mixture in the melt, which was then allowed to cool and comminute.

Bevorzugt trug man dabei den feinteiligen Kalk in den Strahl des aus dem Ofen abgestochenen Carbides ein. Obwohl die in Carbidschmelze eintragbare Menge Kalk begrenzt und das Arbeiten mit flüssigem Carbid mit Gefahren verbunden ist, war man in Fachkreisen bisher der Auffassung, auf diese Methode nicht verzichten zu können, da man der Meinung war, nur eine in der Schmelze hergestellte Mischung von CaC2 und CaO sei für eine Entschwefelung von Metallschmelzen am besten geeignet.The finely divided lime was preferably introduced into the jet of carbide tapped from the furnace. Although the amount of lime that can be introduced into the molten carbide is limited and working with liquid carbide is associated with dangers, it was previously believed in specialist circles that this method could not be dispensed with because it was believed that only a mixture of CaC produced in the melt 2 and CaO are best suited for the desulfurization of metal melts.

Entschwefelungsmittel auf Basis von Calciumcarbid, welche Stoffe enthalten, die bei der Temperatur der Metallschmelze Wasser abspalten, sind bereits aus der DE-B2-22 52 795 bekannt. Diese Mittel, welche Mischungen von handelsüblichem Carbid mit beispielsweise Ca(OHh als wasserabspaltendem Stoff darstellen, haben den Nachteil, dass sie durch mechanisches Vermischen hergestellte Gemenge sind, in denen Carbidteilchen getrennt neben Ca(OH)2-Teilchen vorliegen, was bei Einsatz dieser Produkte zu einem höheren Verbrauch, ungleichmässigen und heftigen Gasreaktionen und einer grossen Streubreite bezüglich der Entschwefelungswirkung führt, wodurch ein gezielter Einsatz dieser Mittel erschwert wird.Desulphurization agents based on calcium carbide, which contain substances which release water at the temperature of the molten metal, are already known from DE-B2-22 52 795. These agents, which are mixtures of commercially available carbide with, for example, Ca (OHh as a water-releasing substance, have the disadvantage that they are mixtures produced by mechanical mixing, in which carbide particles are present separately from Ca (OH) 2 particles, which is the case when these products are used leads to a higher consumption, uneven and violent gas reactions and a large spread regarding the desulfurization effect, which makes a targeted use of these agents difficult.

Überraschenderweise wurde nun gefunden, dass man die Nachteile der bekannten Arbeitsweisen vermeiden und ein hochwirksames Entschwefelungsmittel für Roheisen- und Stahlschmelzen erhalten kann, wenn man zunächst auf thermischem Wege aus Kalk und Koks ein Carbid-Calciumoxid-Ausgangsschmelzgemisch mit einem beliebigen CaO-Gehalt von 20 bis 80% erzeugt, welches man durch Abkühlenlassen zu einem Block erstarren lässt. Während der erstarrte Block noch eine Durchschnittstemperatur von mehr als 400°C, vorzugsweise zwischen 400°C und der Erstarrungstemperatur der Schmelze aufweist, bricht man ihn dann auf Korngrössen kleiner als 150 mm vor und gibt auf das zerkleinerte und noch mindestens 400°C heisse Gemisch Calciumoxid in einer solchen Menge auf, dass der sich in der entstehenden Mischung ergebende Gesamtgehalt an CaO dem im Endprodukt gewünschten CaO-Gehalt entspricht. Vorzugsweise gibt man so viel Calciumoxid auf, dass sich in der Mischung ein Gesamtgehalt an CaO von über 45 bis 90 Gew% ergibt. Anschliessend wird dann die Mischung unter intensiver Vermengung und in Gegenwart von Luft oder Stickstoff mit einem Feuchtigkeitsgehalt von 5 bis 20 g/m3 (bei 1,013 bar und 273,15 K) bei Temperaturen unterhalb 100°C, vorzugsweise bei 10-15°C, auf Korngrössen kleiner als 10 mm, vorzugsweise kleiner als 100 11m, gemahlen.Surprisingly, it has now been found that the disadvantages of the known procedures can be avoided and a highly effective desulfurization agent for pig iron and steel melts can be obtained if a carbide-calcium oxide starting melt mixture with any CaO content of 20 to is first obtained thermally from lime and coke 80% generated, which is allowed to solidify into a block by allowing it to cool. While the solidified block still has an average temperature of more than 400 ° C, preferably between 400 ° C and the solidification temperature of the melt, it is then broken down to grain sizes less than 150 mm and added to the comminuted mixture, which is still at least 400 ° C hot Calcium oxide in such an amount that the total CaO content in the resulting mixture corresponds to the CaO content desired in the end product. It is preferable to add enough calcium oxide to give a total CaO content of over 45 to 90% by weight in the mixture. The mixture is then mixed vigorously and 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) at temperatures below 100 ° C., preferably at 10-15 ° C. , ground to grain sizes less than 10 mm, preferably less than 100 1 1m.

Vorzugsweise setzt man ein Calciumcarbid-Calciumoxid-Ausgangsschmelzgemisch mit einem CaO-Gehalt von 20 bis 45 Gew% ein, das in bekannter Weise auf thermischem Wege aus Kalk und Koks gewonnen wurde. Man kann aber auch so verfahren, dass man zunächst ein Calciumcarbid- Calciumoxid- Ausgangsschmelzgemisch mit einem CaO-Gehalt von über 45 bis 80 Gew% herstellt, indem man in eine vorliegende Calciumcarbidschmelze, die einen Calciumoxidgehalt bis zu 45 Gew% aufweist, feinteiliges Calciumoxid bis zu einem CaO-Gehalt von maximal bis zu 80 Gew% einträgt und erst dann das Ganze zu einem Block erstarren lässt, bevor man diesen bei Temperaturen oberhalb 400°C vorbricht.It is preferable to use a calcium carbide-calcium oxide starting melt mixture with a CaO content of 20 to 45% by weight, which was obtained in a known manner from lime and coke in a thermal manner. However, one can also proceed in such a way that a calcium carbide-calcium oxide starting melt mixture with a CaO content of over 45 to 80% by weight is first produced by adding finely divided calcium oxide to an existing calcium carbide melt which has a calcium oxide content of up to 45% by weight to a CaO content of up to 80% by weight and only then solidify the whole into a block before breaking it at temperatures above 400 ° C.

Ausser dass das Vermischen des Kalkes mit einer Carbidschmelze und den damit verbundenen Schwierigkeiten vermieden werden kann, besitzt das erfindungsgemässe Verfahren u.a. auch die weiteren Vorteile, dass zur Erzeugung der Carbidschmelze nicht jeweils eine bestimmte Möllerzusammensetzung eingestellt, und dass der Kalk vorher nicht auf eine bestimmte Korngrösse feingemahlen werden muss, sondern dass von einem Carbidblock ausgegangen werden kann, dessen CaC2:CaO-Gewichtsverhältnis innerhalb eines sehr weiten Bereiches schwanken, d.h. praktisch beliebig sein kann und der Kalk auch in grobkörniger Form, beispielsweise in einer Korngrösse zwischen 8 und 60 mm, eingesetzt werden kann.In addition to the fact that mixing the lime with a carbide melt and the difficulties associated therewith can be avoided, the method according to the invention also has the further advantages, inter alia, that a certain Möller composition is not set in each case to produce the carbide melt, and that the lime does not previously have a specific grain size must be finely ground, but that it can be assumed that a carbide block whose CaC 2 : CaO weight ratio fluctuates within a very wide range, that is to say can be practically arbitrary, and the lime also in coarse-grained form, for example in a grain size between 8 and 60 mm, can be used.

Ein weiterer Vorteil des erfindungsgemäss hergestellten Mittels besteht darin, dass auf der Oberfläche jedes einzelnen Kornes Ca(OH)2 dicht neben CaC2 vorliegt, wodurch die Entschwefelungsreaktion sehr früh und gleichmässig in Gang gesetzt wird. Dadurch werden bei vergleichbaren Entschwefelungsergebnissen geringere Mengen des Entschwefelungsmittels benötigt und gezieltere Ergebnisse ermöglicht.A further advantage of the inventive agent prepared is that densely present on the surface of each grain Ca (OH) 2 addition CaC 2, is set very early and uniformly in motion whereby the desulfurizing reaction. As a result, ver Similar desulfurization results require smaller amounts of the desulfurization agent and enables more targeted results.

Beispiel 1example 1

Aus einer für die Herstellung von technischem Carbid üblichen Schmelze mit einem CaC2-Gehalt von 80 Gew% und CaO-Gehalt von 20 Gew% wurde in einem Tiegel durch Abkühlenlassen dieser Schmelze in bekannter Weise ein Carbidblock entsprechender Zusammensetzung erzeugt. Nachdem sich der Block auf eine Durchschnittstemperatur von etwa 600°C abgekühlt hatte, wurde er auf Korngrössen kleiner als 150 mm vorgebrochen und das noch 500°C heisse Carbid mit so viel Kalk einer Korngrösse von 8 bis 60 mm überschichtet, dass die sich ergebende Mischung einen CaO-Gehalt von insgesamt 50 Gew% enthielt.From a melt customary for the production of technical carbide with a CaC 2 content of 80% by weight and a CaO content of 20% by weight, a carbide block of corresponding composition was produced in a crucible in a known manner by allowing this melt to cool. After the block had cooled to an average temperature of about 600 ° C, it was crushed to grain sizes smaller than 150 mm and the carbide, which was still 500 ° C, was covered with so much lime with a grain size of 8 to 60 mm that the resulting mixture contained a total CaO content of 50% by weight.

Anschliessend wurde die Mischung 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 zwischen 0 und 100 11m gemahlen.The mixture was then passed through to a particle size between 0 and 100 1 while 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 Ground 1m.

Mit 1500 kg von diesem Produkt wurden 300 000 kg einer Roheisenschmelze, die 0.03 Gew% Schwefel enthielt, in bekannter Weise entschwefelt. Der S-Gehalt des behandelten Eisens betrug weniger als 0,005 Gew%.With 1500 kg of this product, 300,000 kg of a pig iron melt containing 0.03% by weight of sulfur were desulfurized in a known manner. The S content of the treated iron was less than 0.005% by weight.

Beispiel 2Example 2

In bekannter Weise wird aus Kalk und Koks Calciumcarbid thermisch hergestellt, wobei die Kalk-Koks-Mischung im gesamten Möller auf ein Gewichtsverhältnis von etwa 110:40 eingestellt wird, was einem Carbid mit einem CaO-Gehalt von etwa 45 Gew% entspricht.Calcium carbide is produced thermally from lime and coke in a known manner, the lime-coke mixture in the entire Möller being adjusted to a weight ratio of approximately 110:40, which corresponds to a carbide with a CaO content of approximately 45% by weight.

Dem Abstichstrahl dieses Carbides wird CaO der Körnung 3-8 mm in einer solchen Menge zudosiert, dass sich im Abstichtiegel ein Durchschnittsgehalt von ca. 80 Gew% CaO ergibt (auf 1 Tonne Abstichstrahl etwa 1,2-1,3 t CaO). Nach dem Abkühlen des Tiegels auf eine Durchschnittstemperatur von nicht unter 600°C, was bereits nach 4 Stunden der Fall ist, wird der Block auf eine Korngrösse kleiner als 150 mm vorgebrochen und auf das heisse Gemisch so viel Kalk der Körnung 8 bis 60 mm geschichtet, dass der Durchschnitts-CaO-Gehalt 90 Gew% beträgt. Anschliessend wird unter Durchleiten von 1500 m3/h Luft mit einem Feuchtigkeitsgehalt von 10 g/m3 (bei 15°C) in einer Rotatiosmühle mit einem Durchsatz von 500 kg/h bei 50°C auf eine Korngrösse kleiner als 100 11m gemahlen. Mit diesem Gemisch werden, bezogen auf den Calciumcarbidgehalt, die gleichen Entschwefelungsergebnisse erzielt, wie im Beispiel 1 geschildert.CaO with a grain size of 3-8 mm is added to the tapping jet of this carbide in such an amount that an average content of approx. 80% by weight CaO results in the tapping crucible (about 1.2-1.3 t CaO per tonne of tapping jet). After the crucible has cooled to an average temperature of not less than 600 ° C, which is already the case after 4 hours, the block is pre-broken to a grain size of less than 150 mm and as much lime with a grain size of 8 to 60 mm is layered on the hot mixture that the average CaO content is 90% by weight. Subsequently, while passing through 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 a grain size of less than 100 1 1m . With this mixture, based on the calcium carbide content, the same desulfurization results are achieved as described in Example 1.

Claims (8)

1. Process for the manufacture of desulfurizing agents, containing 1-6 weight% chemically combined water, based on calcium oxide-containing calcium carbide for crude iron and steel melts, which comprises: producing from lime and coke a molten mixture of calcium carbide and calcium oxide having a CaO content of 20 to 80 by weight; allowing the mixture to cool and solidify into a block; rough-crushing the solidified block while it still has an average temperature of more than 400°C to particles with a size of less than 150 mm; admixing the comminuted mixture, which still has a temperature of at least 400°C, with a quantity of calcium oxide necessary to establish in the resulting mixture a total content of CaO corresponding to the CaO content desired in the end product, and then grinding the mixture with thorough agitation and in the presence of air or nitrogen containing 5-20 g/m3 moisture (at 1.013 bar and 273.15 K) at temperatures below 100°C to particles with a size of less than 10 mm.
2. Process as claimed in claim 1, wherein coarse CaO with a size of 8 to 60 mm is added to the rough-crushed mixture.
3. Process as claimed in claim 1 or 2, wherein the precrushed mixture is admixed with a quantity of CaO necessary to establish in the resulting mixture a CaO content of 45-90% by weight.
4. Process as claimed in any of claims 1 to 3, wherein the mixture is precrushed at temperatures of between 400°C and the solidification temperature.
5. Process as claimed in any of claims 1 to 4, wherein the molten starting mixture of calcium carbide and calcium oxide with a CaO content of 20 to 45% by weight is produced from lime and coke in customary manner by thermal treatment.
6. Process as claimed in any of claims 1 to 4, wherein the molten starting mixture of calcium carbide and calcium oxide with a CaO content of more than 45% up to 80% by weight is produced by introducing finely divided calcium oxide into an existing calcium carbide melt containing up to 45% by weight of CaO until establishment therein of a maximum CaO content of up to 80% by weight and then allowing the whole to solidify into a block.
7. Process as claimed in any of claims 1 to 6, wherein the mixture is ground at 10°-50°C, to particles with a size of less than 10 mm.
8. Process as claimed in any of claims 1 to 7, wherein the mixture is ground to particles with a size of less than 100 µm.
EP80107915A 1979-12-29 1980-12-15 Process for producing desulfurizing agents for pig iron or steel melts Expired EP0031534B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT80107915T ATE9101T1 (en) 1979-12-29 1980-12-15 PROCESS FOR THE MANUFACTURE OF DESULPHURIZING AGENTS FOR MELTED PIG IRON OR STEEL.

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Application Number Priority Date Filing Date Title
DE19792952686 DE2952686A1 (en) 1979-12-29 1979-12-29 METHOD FOR THE PRODUCTION OF DESULFURING AGENTS FOR BOD IRON OR STEEL MELT
DE2952686 1979-12-29

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EP0031534A1 EP0031534A1 (en) 1981-07-08
EP0031534B1 true EP0031534B1 (en) 1984-08-22

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US (1) US4368071A (en)
EP (1) EP0031534B1 (en)
JP (1) JPS5698413A (en)
AT (1) ATE9101T1 (en)
AU (1) AU532989B2 (en)
BR (1) BR8008500A (en)
DD (1) DD155527A5 (en)
DE (2) DE2952686A1 (en)
DK (1) DK151569C (en)
ES (1) ES8200146A1 (en)
IN (1) IN153342B (en)
MX (1) MX154954A (en)
NO (1) NO153500C (en)
PL (1) PL125648B1 (en)
SU (1) SU1269739A3 (en)
ZA (1) ZA808064B (en)

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Publication number Priority date Publication date Assignee Title
ES8200147A1 (en) * 1979-12-29 1981-11-01 Hoechst Ag Desulphurising composition and process for its production.
DE3111510A1 (en) * 1981-03-24 1982-10-07 Hoechst Ag, 6000 Frankfurt DESULFURATION MIXTURE AND METHOD FOR THE PRODUCTION THEREOF
DE3111509A1 (en) * 1981-03-24 1982-10-07 Hoechst Ag, 6000 Frankfurt METHOD FOR THE PRODUCTION OF DESULFURING AGENTS FOR BOD IRON OR STEEL MELT
CA1243646A (en) * 1984-12-04 1988-10-25 William K. Kodatsky Method for treating carbide-based desulfurizing reagents for injection into molten iron
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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Publication number Priority date Publication date Assignee Title
AT264560B (en) * 1966-08-25 1968-09-10 Gustav Dipl Ing Wolfram Basic steelmaking process
DE1935567B2 (en) * 1969-07-12 1971-05-13 Knapsack AG, 5033 Hurth Knapsack PROCESS FOR THE PRODUCTION OF CALCIUM CARBIDE OF CERTAIN QUALITY
DE2326539B2 (en) * 1973-05-24 1975-03-27 Sueddeutsche Kalkstickstoff-Werke Ag, 8223 Trostberg Process for the production of a desulphurisation mixture for iron melts from calcium carbide and at least one water-containing substance
DE1919414B2 (en) * 1969-04-17 1977-07-14 Hoechst Ag, 6000 Frankfurt METHOD AND DEVICE FOR COOLING CALCIUM CARBIDE PICKED IN VESSELS
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
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
EP0019087A1 (en) * 1979-05-14 1980-11-26 Hoechst Aktiengesellschaft Desulphurising agents for pig iron and steel melts, and process for their manufacture

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DE1758250B1 (en) * 1968-04-29 1971-10-28 Sueddeutsche Kalkstickstoff Agent for the desulphurisation of iron melts
DE2252795C3 (en) * 1972-10-27 1982-09-09 Skw Trostberg Ag, 8223 Trostberg Desulphurizing agent for pig iron and ferro-alloy melts
FR2432550A1 (en) * 1978-08-04 1980-02-29 Sueddeutsche Kalkstickstoff PROCESS FOR THE MANUFACTURE OF AN EASILY FLOWABLE PULVERULATED DESULFURIZATION MIXTURE

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT264560B (en) * 1966-08-25 1968-09-10 Gustav Dipl Ing Wolfram Basic steelmaking process
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
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
DE2326539B2 (en) * 1973-05-24 1975-03-27 Sueddeutsche Kalkstickstoff-Werke Ag, 8223 Trostberg Process for the production of a desulphurisation mixture for iron melts from calcium carbide and at least one water-containing substance
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
EP0019087A1 (en) * 1979-05-14 1980-11-26 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

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AU532989B2 (en) 1983-10-20
DK151569B (en) 1987-12-14
PL125648B1 (en) 1983-06-30
NO803924L (en) 1981-06-30
DE3069043D1 (en) 1984-09-27
EP0031534A1 (en) 1981-07-08
ZA808064B (en) 1982-01-27
AU6585480A (en) 1981-07-09
MX154954A (en) 1988-01-14
DD155527A5 (en) 1982-06-16
US4368071A (en) 1983-01-11
PL228751A1 (en) 1981-09-04
DE2952686A1 (en) 1981-07-02
ATE9101T1 (en) 1984-09-15
DK550880A (en) 1981-06-30
NO153500C (en) 1986-04-02
DK151569C (en) 1988-05-30
NO153500B (en) 1985-12-23
JPS5698413A (en) 1981-08-07
SU1269739A3 (en) 1986-11-07
BR8008500A (en) 1981-07-14
JPS6327406B2 (en) 1988-06-02
ES497685A0 (en) 1981-11-01
IN153342B (en) 1984-07-07
ES8200146A1 (en) 1981-11-01

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