EP0387580A1 - Agent and method for desulfurizing molten metals - Google Patents

Agent and method for desulfurizing molten metals Download PDF

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Publication number
EP0387580A1
EP0387580A1 EP90103671A EP90103671A EP0387580A1 EP 0387580 A1 EP0387580 A1 EP 0387580A1 EP 90103671 A EP90103671 A EP 90103671A EP 90103671 A EP90103671 A EP 90103671A EP 0387580 A1 EP0387580 A1 EP 0387580A1
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Prior art keywords
cac2
weight
gas
magnesium
cao
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German (de)
French (fr)
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Hermann Dr. Schrödter
Albert Braun
Harald Dr. Scholz
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Hoechst AG
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Hoechst AG
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C1/00—Refining of pig-iron; Cast iron
    • C21C1/02—Dephosphorising or desulfurising
    • C21C1/025—Agents used for dephosphorising or desulfurising

Definitions

  • the present invention relates to an agent for the desulfurization of molten metals, in particular molten iron, on the basis of CaC2-CaO crystal mixtures obtained in the melt flow and to methods for desulfurizing molten metals using this agent.
  • the agent for the desulfurization of pig iron or steel melts according to US Pat. No. 4,323,392, which contains 20 to 55% by weight of CaC2 and 45 to 80% by weight of CaO, is prepared by using a calcium carbide melt obtained in a known manner with a CaO- Content of up to 45% by weight at temperatures up to 2000 ° C, finely divided calcium oxide in a total amount of 48 to 95% by weight, based on the end product.
  • the fine-grained agent for desulfurizing molten iron according to EP-OS 226 994 essentially consists of technical calcium carbide (containing 65 to 85% by weight CaC2) and dried coal with at least 15% by weight of volatile components, the carbon content being 2 to 50% by weight. can be. Furthermore, the fine grain Some agents also contain magnesium.
  • a disadvantage of the last-mentioned fine-grained agent is that it contains a high proportion of CaC2, which has a negative effect on the economy of the desulfurization of molten iron.
  • This is achieved according to the invention in that it consists of the components CaC2-CaO crystal mixture with a maximum of 62% by weight, in particular a maximum of 60% by weight of CaC2, gas-releasing substances and 0 to 44% by weight of metallic magnesium.
  • both of these are fluidized mixture consisting of CaC2-CaO crystal mixture and gas-releasing substances as well as the magnesium separately and combines both fluidates immediately before they enter the melt or the three components CaC2-CaO crystal mixture, gas-releasing substances and magnesium are fluidized together and bring the fluidate into the Melt down. Dry air, nitrogen, noble gases or their mixtures can be used for fluidization.
  • the agent according to the invention has grain sizes of at least 90% by weight ⁇ 100 ⁇ m, preferably 85% by weight ⁇ 63 ⁇ m.
  • a flow improver 0.01 to 0.7% by weight of a flow improver can be added to the agent according to the invention.
  • a carbon dioxide-releasing substance for example dolomite or calcium carbonate, can also be added to the agent according to the invention.
  • the desulfurization effect is improved compared to the prior art when using the agent according to the invention.
  • the amount of desulphurising agent to be used per ton of pig iron melt is calculated from the initial sulfur content and the target final sulfur content in the desulfurization of pig iron melts:
  • Desulphurization agents which are known from EP-OS 226 994, were used for experiments A and C, while desulphurization agents according to the invention were used for experiments B, D, E and F. Finally, in experiment E, the desulfurization agent was introduced into the pig iron melt by co-injection of CaC2 / CaO flame-coal mixture on the one hand and magnesium on the other hand (cf. claims 7 and 9).
  • Desulphurization agents which are known from EP-OS 226 994 were used for experiments G and I, while desulphurization agents according to the invention were used for experiments H, J and K. TABLE 1 attempt Desulfurizing agent RE [t] Mean [kg / tRE] Mean [kg / min] Gas [NL / kg] S A S E B [min] K A 95% carbide ( ⁇ 65% CaC2) air 5% brown coal 135 1.95 40 7.0 0.033 0.012 6.6 4.43 B 85% CaC2 / CaO (54% CaC2) air 15% flame coal 300 2.83 70 6.8 0.037 0.008 12.1 4.25 C.

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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)

Abstract

Ein Mittel zum Entschwefeln von Metallschmelzen, insbesondere von geschmolzenem Eisen, besteht aus den Komponenten CaC2-CaO-Kristallgemenge mit maximal 62 Gewichts% CaC2, gasabspaltende Substanzen und 0 bis 44 gewichts% metallisches Magnesium. Zum Entschwefeln von Metallschmelzen, insbesondere von geschmolzenem Eisen, unter Verwendung dieses Mittels fluidisiert man entweder sowohl das aus den Komponenten CaC2- CaO-Kristallgemenge und gasabspaltenden Substanzen bestehende Gemisch als auch das Magnesium getrennt und vereinigt beide Fluidate unmittelbar vor ihrem Eintritt in die Schmelze oder man fluidisiert die Komponenten CaC2-CaO-Kristallgemenge, gasabspaltende Substanzen und Magnesium, gemeinsam und bringt das Fluidat in die Schmelze ein.A means for desulfurizing molten metals, in particular molten iron, consists of the components CaC2-CaO crystal mixture with a maximum of 62% by weight CaC2, gas-releasing substances and 0 to 44% by weight metallic magnesium. To desulfurize metal melts, in particular molten iron, using this agent, either the mixture consisting of the components CaC2-CaO crystal mixture and gas-releasing substances as well as the magnesium are fluidized and the two fluidates are combined immediately before they enter the melt or one is combined fluidizes the components CaC2-CaO crystal mixture, gas-releasing substances and magnesium, together and introduces the fluidate into the melt.

Description

Die vorliegende Erfindung betrifft ein Mittel zum Entschwe­feln von Metallschmelzen, insbesondere von geschmolzenem Eisen, auf der Grundlage von im Schmelzfluß gewonnenen CaC₂-CaO-Kristallgemengen sowie Verfahren zum Entschwefeln von Metallschmelzen unter Verwendung dieses Mittels.The present invention relates to an agent for the desulfurization of molten metals, in particular molten iron, on the basis of CaC₂-CaO crystal mixtures obtained in the melt flow and to methods for desulfurizing molten metals using this agent.

Aus der US-PS 3 771 259 ist ein Verfahren zur Herstellung von niederlitrigem Calciumcarbid aus höherlitrigem Calcium­carbid bekannt, bei welchem man in flüssiges höherlitriges Calciumcarbid Calciumoxid in einer Korngröße von 1 bis 8 mm einträgt, wobei es besonders vorteilhaft ist, das Calcium­oxid während des Abstiches in den schmelzflüssigen Calcium­carbidstrahl einzudosieren. Dadurch wird die Litrigkeit des schmelzflüssigen Calciumcarbids von 280 bis 300 l Acety­len/kg Carbid auf 230 bis 260 l Acetylen/kg Carbid herabge­setzt.From US Pat. No. 3,771,259 a process for the production of low-liter calcium carbide from higher-liter calcium carbide is known, in which calcium oxide in a grain size of 1 to 8 mm is introduced into liquid higher-liter calcium carbide, it being particularly advantageous to remove the calcium oxide during the tapping dosed into the molten calcium carbide jet. This reduces the liquidity of the molten calcium carbide from 280 to 300 l acetylene / kg carbide to 230 to 260 l acetylene / kg carbide.

Das Mittel zum Entschwefeln von Roheisen- oder Stahlschmel­zen nach der US-PS 4 323 392, welches 20 bis 55 Gewichts% CaC₂ und 45 bis 80 Gewichts% CaO enthält, wird hergestellt, indem man in eine in bekannter Weise gewonnene Calciumcar­bidschmelze mit einem CaO-Gehalt bis zu 45 Gewichts% auf Temperaturen bis zu 2000°C vorerhitztes, feinteiliges Cal­ciumoxid in einer Gesamtmenge von 48 bis 95 Gewichts%, be­zogen auf das Endprodukt, einbringt.The agent for the desulfurization of pig iron or steel melts according to US Pat. No. 4,323,392, which contains 20 to 55% by weight of CaC₂ and 45 to 80% by weight of CaO, is prepared by using a calcium carbide melt obtained in a known manner with a CaO- Content of up to 45% by weight at temperatures up to 2000 ° C, finely divided calcium oxide in a total amount of 48 to 95% by weight, based on the end product.

Schließlich besteht das feinkörnige Mittel zum Entschwefeln von geschmolzenem Eisen nach der EP-OS 226 994 im wesentli­chen aus technischem Calciumcarbid (enthaltend 65 bis 85 Gewichts% CaC₂) und getrockneter Kohle mit mindestens 15 Gewichts% flüchtigen Bestandteilen, wobei der Kohlegehalt 2 bis 50 Gewichts% betragen kann. Weiterhin kann das feinkör­ nige Mittel zusätzlich Magnesium enthalten.Finally, the fine-grained agent for desulfurizing molten iron according to EP-OS 226 994 essentially consists of technical calcium carbide (containing 65 to 85% by weight CaC₂) and dried coal with at least 15% by weight of volatile components, the carbon content being 2 to 50% by weight. can be. Furthermore, the fine grain Some agents also contain magnesium.

Nachteilig ist bei dem zuletzt genannten feinkörnigen Mit­tel, daß es einen hohen CaC₂-Anteil enthält, welcher die Wirtschaftlichkeit der Entschwefelung von Eisenschmelzen negativ beeinflußt.A disadvantage of the last-mentioned fine-grained agent is that it contains a high proportion of CaC₂, which has a negative effect on the economy of the desulfurization of molten iron.

Es ist daher Aufgabe der vorliegenden Erfindung, ein Mittel zum Entschwefeln von Metallschmelzen, insbesondere von ge­schmolzenem Eisen, auf der Grundlage von im Schmelzfluß ge­wonnenen CaC₂-CaO-Kristallgemengen anzugeben, mit welchem bei geringerem CaC₂-Gehalt eine mindestens ebenso gute Ent­schwefelungswirkung wie mit dem aus der EP-OS 226 994 be­kannten feinkörnigen Mittel erzielt wird. Das wird erfin­dungsgemäß dadurch erreicht, daß es aus den Komponenten CaC₂-CaO-Kristallgemenge mit maximal 62 Gewichts%, insbe­sondere maximal 60 Gewichts% CaC₂, gasabspaltende Sub­stanzen und 0 bis 44 Gewichts% metallisches Magnesium be­steht.It is therefore an object of the present invention to provide a means for desulfurizing molten metals, in particular molten iron, on the basis of CaC₂-CaO crystal mixtures obtained in the melt flow, with which, with a lower CaC₂ content, an at least as good desulfurization effect as with EP-OS 226 994 known fine-grained agent is achieved. This is achieved according to the invention in that it consists of the components CaC₂-CaO crystal mixture with a maximum of 62% by weight, in particular a maximum of 60% by weight of CaC₂, gas-releasing substances and 0 to 44% by weight of metallic magnesium.

Das Mittel gemäß der Erfindung kann weiterhin wahlweise, auch dadurch ausgestaltet sein, daß

  • a) die Komponenten CaC₂-CaO-Kristallgemenge mit 50 bis 96 Gewichts% und gasabspaltende Substanzen mit 4 bis 50 Ge­wichts% enthalten sind;
  • b) die Komponente Magnesium mit mindestens 1,5 Gewichts%, vorzugsweise 7 bis 32 Gewichts%, enthalten ist;
  • c) die Komponente CaC₂-CaO-Kristallgemenge mindestens 20 Gewichts% CaC₂ enthält;
  • d) als gasabspaltende Substanzen flüchtige Bestandteile enthaltende Kohlen dienen;
  • e ) die Kohlen 20 bis 60 Gewichts% flüchtige Bestandteile enthalten.
The agent according to the invention can also be optionally, also designed in that
  • a) the components CaC₂-CaO crystal mixture with 50 to 96% by weight and gas-releasing substances with 4 to 50% by weight are included;
  • b) the component magnesium is present in at least 1.5% by weight, preferably 7 to 32% by weight;
  • c) the component CaC₂-CaO crystal mixture contains at least 20% by weight CaC₂;
  • d) serve as carbons containing volatile constituents as gas-releasing substances;
  • e) the coals contain 20 to 60% by weight of volatile components.

Beim Verfahren zum Entschwefeln von Metallschmelzen, insbe­sondere von geschmolzenem Eisen, unter Verwendung des er­findungsgemäßen Mittels fluidisiert man entweder sowohl das aus CaC₂-CaO-Kristallgemenge und gasabspaltenden Substanzen bestehende Gemisch als auch das Magnesium getrennt und ver­einigt beide Fluidate unmittelbar vor ihrem Eintritt in die schmelze oder man fluidisiert die drei Komponenten CaC₂-­CaO-Kristallgemenge, gasabspaltende Substanzen und Magne­sium gemeinsam und bringt das Fluidat in die Schmelze ein. Dabei kann man zur Fluidisierung trockene Luft, Stickstoff, Edelgase oder deren Mischungen verwenden.In the process for desulfurizing molten metals, in particular molten iron, using the agent according to the invention, both of these are fluidized mixture consisting of CaC₂-CaO crystal mixture and gas-releasing substances as well as the magnesium separately and combines both fluidates immediately before they enter the melt or the three components CaC₂-CaO crystal mixture, gas-releasing substances and magnesium are fluidized together and bring the fluidate into the Melt down. Dry air, nitrogen, noble gases or their mixtures can be used for fluidization.

Das erfindungsgemäße Mittel weist Korngrößen von mindestens 90 Gewichts% < 100 µm, vorzugsweise 85 Gewichts% < 63 µm auf.The agent according to the invention has grain sizes of at least 90% by weight <100 µm, preferably 85% by weight <63 µm.

Dem Mittel gemäß der Erfindung kann 0,01 bis 0,7 Gewichts% eines Fließverbesserers zugesetzt sein.0.01 to 0.7% by weight of a flow improver can be added to the agent according to the invention.

Dem erfindungsgemäßen Mittel kann weiterhin eine Kohlen­dioxid abspaltende Substanz, beispielsweise Dolomit oder Calciumcarbonat, zugesetzt sein.A carbon dioxide-releasing substance, for example dolomite or calcium carbonate, can also be added to the agent according to the invention.

Bei Einsatz des erfindungsgemäßen Mittels wird eine Verrin­gerung der Entschwefelungskosten erreicht, da in diesem Mittel CaC₂ durch CaO ersetzt ist und der Wert beider Stof­fe etwa 8 : 1 ist.When using the agent according to the invention, a reduction in the desulfurization costs is achieved, since in this agent CaC₂ is replaced by CaO and the value of both substances is approximately 8: 1.

Ausweislich der Beispiele wird bei Verwendung des Mittels gemäß der Erfindung die Entschwefelungswirkung gegenüber dem Stand der Technik verbessert.According to the examples, the desulfurization effect is improved compared to the prior art when using the agent according to the invention.

Die folgenden Beispiele sind im wesentlichen in den Tabel­len 1 und 2 zusammengefaßt, wobei in den Tabellen die fol­genden Abkürzungen verwendet wurden:
Carbid : technisches Calciumcarbid (65 bis 85 Gewichts% CaC₂)
CaC₂/CaO : im Schmelzfluß erzeugtes Kristall­gemenge aus Calciumcarbid und Cal­ciumoxid
% : Gewichts%
RE [t] : Roheisenmenge in Tonnen
Mittel [kg/t RE] : kg Entschwefelungsmittel je Tonne Roheisen
Mittel [kg/min] : je Minute in die Roheisenschmelze eingebrachte kg Entschwefelungs­mittel
Gas [Nl/kg] : zum Einblasen des Entschwefelungs­mittels in die Eisenschmelze ver­wendetes Fördergas; aufgewandte Fördergasmenge je kg Entschwefe­lungsmittel
SA : Schwefelgehalt der Roheisenschmel­ze vor der Behandlung mit Ent­schwefelungsmittel; in Gewichts%
SE : Schwefelgehalt der Roheisenschmel­ze nach der Behandlung mit Ent­schwefelungsmittel; in Gewichts%
B [min] : Behandlungsdauer in Minuten
K : Kennwert für die Wirksamkeit des EntschwefelungsmittelsThe following examples are essentially summarized in Tables 1 and 2, the following abbreviations being used in the tables:
Carbide: technical calcium carbide (65 to 85% by weight CaC₂)
CaC₂ / CaO: Crystalline mixture of calcium carbide and calcium oxide generated in the melt flow
%: Weight%
RE [t]: amount of pig iron in tons
Average [kg / t RE]: kg desulphurizing agent per ton of pig iron
Average [kg / min]: kg of desulphurising agent introduced into the pig iron melt per minute
Gas [Nl / kg]: conveying gas used to inject the desulfurizing agent into the molten iron; amount of conveying gas used per kg of desulfurizing agent
S A : sulfur content of the pig iron melt before treatment with desulfurizing agent; in weight%
S E : sulfur content of the pig iron melt after treatment with desulfurizing agent; in weight%
B [min]: duration of treatment in minutes
K: characteristic value for the effectiveness of the desulfurization agent

Es besteht folgende Beziehung zwischen der Roheisen­menge t RE, dem Ausgangsschwefelgehalt SA, dem End­schwefelgehalt SE und der aufgewandten Menge Entschwe­felungsmittel:

Figure imgb0001
(vergl. H. M. Delhey: "Beitrag über die Entschwefelung von flüssigem Roheisen mit Kalk und Calciumcarbid nach dem Tauchlanzenverfahren", Dissertation, Technische Universität Clausthal, 1988).The following relationship exists between the amount of pig iron t RE, the initial sulfur content S A , the final sulfur content S E and the amount of desulfurizing agent used:
Figure imgb0001
 (cf. HM Delhey: "Article on the desulphurization of molten pig iron with lime and calcium carbide using the immersion lance method", dissertation, Clausthal University of Technology, 1988).

Mit Hilfe dieser Beziehung wird bei der Entschwefelung von Roheisenschmelzen aus Ausgangsschwefelgehalt und angestrebtem Endschwefelgehalt die pro t Roheisen­schmelze aufzuwendende Menge Entschwefelungsmittel berechnet:

Figure imgb0002
With the help of this relationship, the amount of desulphurising agent to be used per ton of pig iron melt is calculated from the initial sulfur content and the target final sulfur content in the desulfurization of pig iron melts:
Figure imgb0002

Die Beziehung zeigt, daß der Verbrauch an Entschwefe­lungsmittel pro t Roheisenschmelze für ein angestreb­tes Verhältnis SA/SE um so niedriger ist, je kleiner die Reaktionskonstante K ist.The relationship shows that the lower the reaction constant K, the lower the consumption of desulfurization agent per ton of pig iron melt for a desired ratio S A / S E.

Beispiel 1example 1

Die Versuche A bis F (vergl. Tabelle 1) wurden in offenen Pfannen durchgeführt.Experiments A to F (see Table 1) were carried out in open pans.

Dabei wurden für die Versuche A und C Entschwefelungsmittel verwendet, welche aus der EP-OS 226 994 bekannt sind, wäh­rend für die Versuche B, D, E und F erfindungsgemäße Ent­schwefelungsmittel zum Einsatz gelangten. Schließlich wurde beim Versuch E das Entschwefelungsmittel durch Coinjektion von CaC₂/CaO-Flammkohle-Gemisch einerseits und Magnesium andererseits in die Roheisenschmelze eingebracht (vergl. die Patentansprüche 7 und 9).Desulphurization agents, which are known from EP-OS 226 994, were used for experiments A and C, while desulphurization agents according to the invention were used for experiments B, D, E and F. Finally, in experiment E, the desulfurization agent was introduced into the pig iron melt by co-injection of CaC₂ / CaO flame-coal mixture on the one hand and magnesium on the other hand (cf. claims 7 and 9).

Beispiel 2Example 2

Die Versuche G bis K (vergl. Tabelle 2) wurden in Torpedo­pfannen durchgeführt.Experiments G to K (see Table 2) were carried out in torpedo pans.

Dabei wurden für die Versuche G und I Entschwefelungsmittel verwendet, welche aus der EP-OS 226 994 bekannt sind, wäh­rend für die Versuche H, J und K erfindungsgemäße Entschwe­felungsmittel zum Einsatz gelangten. TABELLE 1 Versuch Entschwefelungsmittel RE [t] Mittel [kg/tRE] Mittel [kg/min] Gas [NL/kg] SA SE B [min] K A 95 % Carbid (≧ 65 % CaC₂) Luft 5 % Braunkohle 135 1,95 40 7,0 0,033 0,012 6,6 4,43 B 85 % CaC₂/CaO (54 % CaC₂) Luft 15 % Flammkohle 300 2,83 70 6,8 0,037 0,008 12,1 4,25 C 82 % Carbid (≧ 65 % CaC₂) N₂ 5 % Braunkohle 146 2,04 60 6,5 0,034 0,008 5,0 3,24 13 % Magnesium D 82 % CaC₂/CaO (55 % CaC₂) N₂ 8 % Flammkohle 300 1,83 70 6,2 0,030 0,007 7,8 2,90 10 % Magnesium E 82 % CaC₂/CaO (52 % CaC₂) N₂ 5 % Flammkohle 300 1,97 60 6,6 0,042 0,009 9,9 2,94 13 % Magnesium F 85 % CaC₂/CaO (50 % CaC₂) N₂ 5 % Flammkohle 300 2,11 70 6,5 0,051 0,009 9,0 2,80 10 % Magnesium TABELLE 2 Versuch Entschwefelungsmittel RE [t] Mittel [kg/tRE] Mittel [kg/min] Gas [NL/kg] SA SE B [min] K G 85 % Carbid (≧ 65 % CaC₂) N₂ 15 % Flammkohle 159 3,20 45 12,5 0,048 0,012 11,3 5,31 H 85 % CaC₂/CaO (54 % CaC₂) N₂ 15 % Flammkohle 175 2,79 60 10,5 0,050 0,011 8,1 4,25 I 75 % Carbid (≧ 65 % CaC₂) N₂ 15 % Flammkohle 180 2,15 55 15 0,045 0,010 7,0 3,29 10 % Magnesium J 75 % CaC₂/CaO (55 % CaC₂) N₂ 12 % Flammkohle 180 2,29 63 10 0,043 0,007 6,5 2,90 13 % Magnesium K 80 % CaC₂/CaO (52 % CaC₂) N₂ 10 % Flammkohle 170 2,30 65 9,5 0,051 0,009 6,0 3,05 10 % Magnesium Desulphurization agents which are known from EP-OS 226 994 were used for experiments G and I, while desulphurization agents according to the invention were used for experiments H, J and K. TABLE 1 attempt Desulfurizing agent RE [t] Mean [kg / tRE] Mean [kg / min] Gas [NL / kg] S A S E B [min] K A 95% carbide (≧ 65% CaC₂) air 5% brown coal 135 1.95 40 7.0 0.033 0.012 6.6 4.43 B 85% CaC₂ / CaO (54% CaC₂) air 15% flame coal 300 2.83 70 6.8 0.037 0.008 12.1 4.25 C. 82% carbide (≧ 65% CaC₂) N₂ 5% brown coal 146 2.04 60 6.5 0.034 0.008 5.0 3.24 13% magnesium D 82% CaC₂ / CaO (55% CaC₂) N₂ 8% flame coal 300 1.83 70 6.2 0.030 0.007 7.8 2.90 10% magnesium E 82% CaC₂ / CaO (52% CaC₂) N₂ 5% flame coal 300 1.97 60 6.6 0.042 0.009 9.9 2.94 13% magnesium F 85% CaC₂ / CaO (50% CaC₂) N₂ 5% flame coal 300 2.11 70 6.5 0.051 0.009 9.0 2.80 10% magnesium attempt Desulfurizing agent RE [t] Mean [kg / tRE] Mean [kg / min] Gas [NL / kg] S A S E B [min] K G 85% carbide (≧ 65% CaC₂) N₂ 15% flame coal 159 3.20 45 12.5 0.048 0.012 11.3 5.31 H 85% CaC₂ / CaO (54% CaC₂) N₂ 15% flame coal 175 2.79 60 10.5 0.050 0.011 8.1 4.25 I. 75% carbide (≧ 65% CaC₂) N₂ 15% flame coal 180 2.15 55 15 0.045 0.010 7.0 3.29 10% magnesium J 75% CaC₂ / CaO (55% CaC₂) N₂ 12% flame coal 180 2.29 63 10th 0.043 0.007 6.5 2.90 13% magnesium K 80% CaC₂ / CaO (52% CaC₂) N₂ 10% flame coal 170 2.30 65 9.5 0.051 0.009 6.0 3.05 10% magnesium

Claims (9)

1. Mittel zum Entschwefeln von Metallschmelzen, insbesonde­re von geschmolzenem Eisen, auf der Grundlage von im Schmelzfluß gewonnenen CaC₂-CaO-Kristallgemengen, da­durch gekennzeichnet, daß es aus den Komponenten CaC₂-­CaO-Kristallgemenge mit maximal 62 Gewichts%, insbeson­dere maximal 60 Gewichts% CaC₂, gasabspaltende Substan­zen und 0 bis 44 Gewichts% metallisches Magnesium be­steht.1. Means for desulfurizing molten metals, in particular molten iron, on the basis of CaC₂-CaO crystal batches obtained in the melt flow, characterized in that it consists of the components CaC₂-CaO crystal batches with a maximum of 62% by weight, in particular a maximum of 60% by weight CaC₂, gas-releasing substances and 0 to 44% by weight of metallic magnesium. 2. Mittel nach Anspruch 1, dadurch gekennzeichnet, daß die Komponenten CaC₂-CaO-Kristallgemenge mit 50 bis 96 Ge­wichts% und gasabspaltende Substanzen mit 4 bis 50 Ge­wichts% enthalten sind.2. Composition according to claim 1, characterized in that the components CaC₂-CaO crystal mixture with 50 to 96% by weight and gas-releasing substances with 4 to 50% by weight are included. 3. Mittel nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß die Komponente Magnesium mit mindestens 1,5 Ge­wichts%, vorzugsweise mit 7 bis 32 Gewichts%, enthalten ist.3. Composition according to claim 1 or 2, characterized in that the component magnesium is contained with at least 1.5% by weight, preferably with 7 to 32% by weight. 4. Mittel nach mindestens einem der Ansprüche 1 bis 3, da­durch gekennzeichnet, daß die Komponente CaC₂-CaO-Kri­stallgemenge mindestens 20 Gewichts% CaC₂ enthält.4. Composition according to at least one of claims 1 to 3, characterized in that the component CaC₂-CaO crystal mixture contains at least 20% by weight CaC₂. 5. Mittel nach mindestens einem der Ansprüche 1 bis 4, da durch gekennzeichnet, daß als gasabspaltende Substanzen flüchtige Bestandteile enthaltende Kohlen dienen.5. Composition according to at least one of claims 1 to 4, characterized in that the gas-releasing substances are used to contain volatile constituents. 6. Mittel nach Anspruch 5, dadurch gekennzeichnet, daß die Kohlen 20 bis 60 Gewichts% flüchtige Bestandteile ent­halten.6. Composition according to claim 5, characterized in that the coals contain 20 to 60% by weight of volatile constituents. 7. Verfahren zum Entschwefeln von Metallschmelzen, insbe­sondere von geschmolzenem Eisen, unter Verwendung des Mittels nach mindestens einem der Ansprüche 1 bis 6, da­durch gekennzeichnet, daß man sowohl das aus den Kompo­nenten CaC₂-CaO-Kristallgemenge und gasabspaltenden Sub­stanzen bestehende Gemisch als auch das Magnesium ge­trennt fluidisiert und beide Fluidate unmittelbar vor ihrem Eintritt in die Schmelze vereinigt.7. A process for desulfurizing molten metals, in particular molten iron, using the agent according to at least one of claims 1 to 6, characterized in that both the mixture consisting of the components CaC₂-CaO crystal mixture and gas-releasing substances and the magnesium fluidized separately and combined both fluidates immediately before they enter the melt. 8. Verfahren zum Entschwefeln von Metallschmelzen, insbe­sondere von geschmolzenem Eisen, unter Verwendung des Mittels nach mindestens einem der Ansprüche 1 bis 6, da­durch gekennzeichnet, daß man die Komponenten CaC₂-­CaO-Kristallgemenge, gasabspaltende Substanzen und Mag­nesium gemeinsam fluidisiert und das Fluidat in die Schmelze einbringt.8. A method for desulfurizing molten metals, in particular molten iron, using the agent according to at least one of claims 1 to 6, characterized in that the components CaC₂-CaO crystal mixture, gas-releasing substances and magnesium are fluidized together and the fluidate in the Introduces melt. 9. Verfahren nach Anspruch 7 oder 8, dadurch gekennzeich­net, daß man zur Fluidisierung trockene Luft, Stick­stoff, Edelgase oder deren Mischungen verwendet.9. The method according to claim 7 or 8, characterized in that dry air, nitrogen, noble gases or mixtures thereof are used for fluidization.
EP90103671A 1989-03-13 1990-02-26 Agent and method for desulfurizing molten metals Withdrawn EP0387580A1 (en)

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US5078784A (en) * 1990-03-14 1992-01-07 Elkem Metals Company Desulfurization agent
US5149364A (en) * 1990-03-14 1992-09-22 Elkem Metals Company Desulfurization agent
US5358550A (en) * 1992-10-26 1994-10-25 Rossborough Manufacturing Company Desulfurization agent
DE4242328C2 (en) * 1992-12-15 1995-06-08 Alfred Dipl Ing Dr Freissmuth Means for desulfurization, dephosphorization, desiliconization and denitrification of pig iron and cast iron melts
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

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DE2907069B2 (en) * 1979-02-23 1981-04-02 Krupp Stahl Ag, 4630 Bochum Agent for the desulphurization of metal melts
EP0019087B1 (en) * 1979-05-14 1983-07-20 Hoechst Aktiengesellschaft Desulphurising agents for pig iron and steel melts, and process for their manufacture
EP0164592A1 (en) * 1984-05-16 1985-12-18 SKW Trostberg Aktiengesellschaft Fine-grained desulfurization agent forron melts, and process for the desulfurization of molten pig iron
EP0226994A1 (en) * 1985-12-17 1987-07-01 SKW Trostberg Aktiengesellschaft Agent for desulphuration of molten iron and process for its production

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NO901142D0 (en) 1990-03-12
DD292478A5 (en) 1991-08-01
JPH02282411A (en) 1990-11-20
PT93412A (en) 1990-11-07
ZA901876B (en) 1990-12-28
NO901142L (en) 1990-09-14
US4988387A (en) 1991-01-29
CA2011380A1 (en) 1990-09-13

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