WO1998021374A2 - Method for treating steel in an electric arc furnace for obtaining a foamed slag - Google Patents
Method for treating steel in an electric arc furnace for obtaining a foamed slag Download PDFInfo
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- WO1998021374A2 WO1998021374A2 PCT/FR1997/002041 FR9702041W WO9821374A2 WO 1998021374 A2 WO1998021374 A2 WO 1998021374A2 FR 9702041 W FR9702041 W FR 9702041W WO 9821374 A2 WO9821374 A2 WO 9821374A2
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- Prior art keywords
- slag
- steel
- carbide
- electric arc
- arc furnace
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Classifications
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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
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/52—Manufacture of steel in electric furnaces
- C21C5/54—Processes yielding slags of special composition
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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
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/36—Processes yielding slags of special composition
- C21C2005/366—Foam slags
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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
- C21C2300/00—Process aspects
- C21C2300/02—Foam creation
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Definitions
- the invention relates to a method of treating steel during its production in an electric arc furnace and, more specifically, a method for ensuring the foaming of the slag covering the bath of liquid steel in the furnace.
- DRI direct reduced iron
- Products such as lime and dolomite, intended to form a slag on the surface of the liquid steel, are added to the charge, as well as carbon, most often in the form of coke, in combination with an injection of oxygen in the oven.
- the simultaneous supply of carbon and oxygen makes it possible to replace part of the electrical energy with chemical energy, to oxidize the impurities, the oxides formed being mainly trapped in the slag, and finally to adjust the carbon level in the steel.
- iron oxide FeO is also formed, the slag of which contains, at the end of the preparation a content of between 20 and 50% by weight depending on the operating parameters of the oven, which constitutes a loss in iron compared to that introduced into raw materials.
- the carbon / oxygen ratio is determined according to the priorities set by the operator, such as, for example, productivity, control of the temperature of the roof walls, noise, the final level of carbon in the steel, the amount of dissolved oxygen or the amount of chemical energy desired.
- the subject of the invention is therefore a method of treating steel in an electric arc furnace to form a foaming slag on the surface of the liquid bath, consisting in injecting, into the slag or in its vicinity, carbide powder.
- calcium in an amount between 3 and 8 kg per tonne of liquid steel.
- the calcium carbide is preferably a technical calcium carbide with at least 75% pure carbide and a particle size of less than 2 mm. It can be used alone or mixed with carbon powder, the total optimal quantity for treatment being between 6 and 8 kg / t of steel.
- Calcium carbide powder can completely or partially replace graphite or anthracite powder, but to obtain a significant effect on iron loss or electrical consumption, it is necessary to use at least 3 kg per tonne of liquid steel.
- a substitution for equal weight of carbon by calcium carbide gives a good result. This is quite surprising since the amount leading to the same release of CO would be 2.7 times greater. Knowing that usually 6 to 8 kg / t of carbon powder is used to obtain a foaming slag, it is advantageous to use the same amount by weight of carbide in substitution.
- the carbide used is, as for other steel applications, so-called “technical” carbide, that is to say carbide resulting from the carbothermic reduction of lime in an electric oven and containing from 15 to 35% by weight of residual lime. It is preferable that the carbide content is more than 75%.
- the particle size is preferably chosen below 2 ⁇ nm 3, that is to say much less than that of the carbide used for ladle refining, generally between 5 and 15 mm. It is also possible to add to the carbide powder suction dust from the electric oven.
- the injection of the carbide powder must be accompanied, like that of carbon, by a concomitant injection of oxygen to obtain an exothermic effect favorable to the various reactions, but preferably a certain lack of oxygen is maintained with respect to the common practice.
- the slag must remain strongly agitated to allow rapid heat transfer and the elimination of the guangue formed on the surface of the carbide grains.
- the oxidation reaction of the carbide can then continue until its complete disappearance from the slag and that of the carbon can take place.
- the carbide is injected under the same conditions as that of carbon, using a lance whose end is located either in the slag, or just above, or at the metal-slag interface.
- the FeO content of the slag is approximately 10% lower, which, for a quantity of slag of the order of 120 kg / t, induces a reduction of 12 kg / t of FeO in the slag, ie a gain of 9 kg of iron (about 1%), not to mention the fact that the quantity of slag used can be reduced.
- the consumption of electricity, with an equal amount of oxygen injected is reduced by around 20 kWh per tonne, which also leads to a reduction in electrode consumption and a reduction in the duration under voltage, leading to a corresponding reduction in the time between 2 power-ups ("tap to tap"). If the operator is not interested in an increase in productivity, he can choose to reduce the quantity of oxygen injected, which reduces the material cost and the energy of injection.
- the treatment method according to the invention applies not only to ordinary steels, but also to alloy steels, in particular stainless steels, produced in an electric oven.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (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)
Abstract
Description
Procédé de traitement de l'acier dans un four électrique à arc pour obtenir un laitier moussant Process for treating steel in an electric arc furnace to obtain a foaming slag
Domaine technique de l'inventionTechnical field of the invention
L'invention concerne un procédé de traitement de l'acier au cours de son élaboration au four électrique à arc et, plus précisément, un procédé permettant d'assurer le moussage du laitier recouvrant le bain d'acier liquide dans le four.The invention relates to a method of treating steel during its production in an electric arc furnace and, more specifically, a method for ensuring the foaming of the slag covering the bath of liquid steel in the furnace.
Etat de la techniqueState of the art
Une partie croissante de l'acier produit dans le monde l'est actuellement par la filière électrique, c'est à dire par élaboration au four électrique à arc à partir soit de ferrailles, soit de fer préréduit (DRI = direct reduced iron), soit de fonte solide ou liquide, ou d'un mélange de ces produits. On ajoute à la charge des produits, tels que la chaux et la dolomie, destinés à former un laitier à la surface de l'acier liquide, ainsi que du carbone, le plus souvent sous forme de coke, en combinaison avec une injection d'oxygène dans le four.A growing part of the steel produced in the world is currently produced by the electrical sector, that is to say by elaboration in an electric arc furnace from either scrap or pre-reduced iron (DRI = direct reduced iron), either solid or liquid iron, or a mixture of these products. Products such as lime and dolomite, intended to form a slag on the surface of the liquid steel, are added to the charge, as well as carbon, most often in the form of coke, in combination with an injection of oxygen in the oven.
L'apport simultané de carbone et d'oxygène permet de remplacer une partie de l'énergie électrique par de l'énergie chimique, d'oxyder les impuretés, les oxydes formés étant en majeure partie piégés dans le laitier, et enfin d'ajuster le niveau de carbone dans l'acier. Par contre, il se forme également de l'oxyde de fer FeO dont le laitier contient, à la fin de l'élaboration une teneur comprise entre 20 et 50% en poids selon les paramètres de fonctionnement du four, ce qui constitue une perte en fer par rapport à celui introduit dans les matières premières.The simultaneous supply of carbon and oxygen makes it possible to replace part of the electrical energy with chemical energy, to oxidize the impurities, the oxides formed being mainly trapped in the slag, and finally to adjust the carbon level in the steel. On the other hand, iron oxide FeO is also formed, the slag of which contains, at the end of the preparation a content of between 20 and 50% by weight depending on the operating parameters of the oven, which constitutes a loss in iron compared to that introduced into raw materials.
Le rapport carbone/oxygène est déterminé en fonction des priorités que se fixe l'exploitant, comme, par exemple, la productivité, le contrôle de la température des parois de voûte, le bruit, le niveau final de carbone dans l'acier, la quantité d'oxygène dissous ou la quantité d'énergie chimique désirée.The carbon / oxygen ratio is determined according to the priorities set by the operator, such as, for example, productivity, control of the temperature of the roof walls, noise, the final level of carbon in the steel, the amount of dissolved oxygen or the amount of chemical energy desired.
Dans le but de mieux contrôler l'oxydation du fer qui affecte le rendement en métal et d'améliorer l'efficacité thermique du four, les aciéries électriques ont développé, depuis quelques années, une technique dite de « laitier moussant », consistant à introduire le carbone par injection, en continu et sous forte pression, d'une poudre carbonée, par exemple une poudre de graphite ou d'anthracite, dans le laitier ou à son voisinage. L'oxydation de ce carbone produit de l'oxyde de carbone CO qui se dégage sous forme de bulles à travers le laitier et produit un effet de moussage. Ce moussage permet de couvrir l'arc électrique, ce qui améliore le rendement, de diminuer les pertes thermiques par rayonnement, de réduire le bruit et de protéger les électrodes. Un exemple représentatif et récent de cette pratique est décrit dans l'article de R.D. MORALES et al. de la société IMEXSA « The Slag Foaming Practice in EAF and Its Influence on the Steelmaking Shop Productivity » ISIJ International, vol. 35, 1995, n° 9, pp. 1054-1062. L'article montre la réduction de la consommation électrique et de la teneur en fer du laitier résultant de l'introduction de la technique du laitier moussant dans le four électrique. Cette réduction est d'autant plus intéressante que la charge est constituée majoritairement de fer préréduit. En effet, dans ce cas, on observe en général une teneur plus élevée en FeO dans le laitier et une quantité de laitier nécessaire plus importante que lorsqu'on utilise des ferrailles, ce qui conduit à une forte augmentation de la perte en fer, laquelle peut doubler en passant, par exemple, de 2% à 4% quand on passe d'une charge de ferrailles à une charge de fer préréduit. Cette substitution conduit également, toutes choses égales par ailleurs, à une augmentation de la consommation électrique.In order to better control the oxidation of iron which affects the metal yield and to improve the thermal efficiency of the furnace, electric steelworks have developed, for a few years, a technique known as “foaming slag”, consisting in introducing carbon by injection, continuously and under high pressure, of a carbonaceous powder, for example a graphite or anthracite powder, into the slag or to its neighborhood. The oxidation of this carbon produces carbon monoxide CO which is released in the form of bubbles through the slag and produces a foaming effect. This foaming makes it possible to cover the electric arc, which improves the efficiency, to reduce the heat losses by radiation, to reduce the noise and to protect the electrodes. A representative and recent example of this practice is described in the article by RD MORALES et al. from IMEXSA "The Slag Foaming Practice in EAF and Its Influence on the Steelmaking Shop Productivity" ISIJ International, vol. 35, 1995, n ° 9, pp. 1054-1062. The article shows the reduction in electricity consumption and in the iron content of the slag resulting from the introduction of the foaming slag technique in the electric oven. This reduction is all the more advantageous since the charge consists mainly of pre-reduced iron. In fact, in this case, a higher FeO content in the slag is generally observed and a greater quantity of slag required than when scrap is used, which leads to a large increase in the iron loss, which can double by passing, for example, from 2% to 4% when one passes from a load of scrap to a load of pre-reduced iron. This substitution also leads, all other things being equal, to an increase in electricity consumption.
Le carbure de calcium est largement utilisé dans l'affinage en poche des aciers, y compris ceux issus des aciéries électriques, mais, à la connaissance des inventeurs, il n'a jamais été utilisé industriellement dans le four électrique lui-même. Ainsi, l'article de G. M. FAULRI G et G. MEDINA « Chaparral's Steelmaking Practice: Then, Now and Why » publié dans les 1994 Electric Furnace Conférence Proceedings, pp. 401-409, avant de décrire longuement l'utilisation du carbure de calcium en poche d'affinage, indique qu' »une pratique efficace en sidérurgie exige un laitier oxydant dans le four et un laitier réducteur en poche » en précisant, un peu plus loin, que « CaC2 est ajouté pour transformer un laitier oxydant en laitier réducteur ». Cet article montre bien qu'il existait, pour le spécialiste de la sidérurgie au four électrique comme pour le producteur de carbure de calcium, un préjugé contre l'utilisation du carbure de calcium dans le four électrique lui-même.Calcium carbide is widely used in ladle refining of steels, including those from electric steel mills, but, to the knowledge of the inventors, it has never been used industrially in the electric furnace itself. Thus, the article by GM FAULRI G and G. MEDINA "Chaparral's Steelmaking Practice: Then, Now and Why" published in the 1994 Electric Furnace Conference Proceedings, pp. 401-409, before describing at length the use of calcium carbide in refining ladle, indicates that "an effective practice in the steel industry requires an oxidizing slag in the furnace and a reducing slag in ladle" by specifying, a little more far, that "CaC 2 is added to transform an oxidizing slag into a reducing slag". This article clearly shows that, for the specialist in the steel industry with an electric furnace, for the producer of calcium carbide, a prejudice against the use of calcium carbide in the electric oven itself.
On peut certes l'envisager comme source alternative de carbone, comme le font par exemple WANG PING et FU IDE de l'université de Beijing dans leur communication au 5ème European Electric Steel Congress à Paris du 19 au 23 juin 1995 « Advances in EAF + LF(V) Process in China ». Selon ces auteurs, on peut utihser, pour former un laitier moussant, C, CaC2 ou SiC comme source de carbone. Pour le carbure, la réaction d'oxydation s'écrit: CaC2 + 3 0 = CaO + 2CO On peut en conclure que, pour obtenir le même effet moussant, il faut avoir le même dégagement de CO et, par conséquent, substituer à 24 kg de carbone 64 kg de carbure, soit presque 3 fois plus en poids. Compte-tenu des prix respectifs du graphite ou de l'anthracite et du carbure de calcium, cette substitution n'est guère intéressante économiquement, et c'est probablement la raison pour laquelle elle n'a pas été mise en oeuvre.We can certainly consider it as an alternative source of carbon, as do for example WANG PING and FU IDE of the University of Beijing in their communication to the 5th European Electric Steel Congress in Paris from June 19 to 23, 1995 "Advances in EAF + LF (V) Process in China ”. According to these authors, C, CaC 2 or SiC can be used to form a foaming slag as a carbon source. For carbide, the oxidation reaction is written: CaC 2 + 3 0 = CaO + 2CO We can conclude that, to obtain the same foaming effect, it is necessary to have the same release of CO and, consequently, to substitute for 24 kg of carbon 64 kg of carbide, almost 3 times more by weight. Taking into account the respective prices of graphite or of anthracite and of calcium carbide, this substitution is of little economic interest, and that is probably the reason why it has not been implemented.
Objet de l'inventionSubject of the invention
La demanderesse a mis en évidence, de manière surprenante, que, pour obtenir en matière de réduction des pertes en fer et de consommation électrique, des résultats au moins aussi bons, sinon meilleurs qu'avec le carbone, on pouvait utihser du carbure de calcium en quantité beaucoup moins importante que celle à laquelle on pouvait s'attendre par substitution stoechiométrique de CaC2 à C.The Applicant has surprisingly demonstrated that, in order to obtain, in terms of reduction of iron losses and electrical consumption, results at least as good, if not better than with carbon, it was possible to use calcium carbide. in a much smaller amount than that which could be expected by stoichiometric substitution of CaC 2 for C.
L'invention a ainsi pour objet un procédé de traitement de l'acier dans un four électrique à arc pour former un laitier moussant à la surface du bain liquide consistant à injecter, dans le laitier ou à son voisinage, de la poudre de carbure de calcium en quantité comprise entre 3 et 8 kg par tonne d'acier liquide.The subject of the invention is therefore a method of treating steel in an electric arc furnace to form a foaming slag on the surface of the liquid bath, consisting in injecting, into the slag or in its vicinity, carbide powder. calcium in an amount between 3 and 8 kg per tonne of liquid steel.
Le carbure de calcium est, de préférence, un carbure de calcium technique à au moins 75% de carbure pur et de granulométrie inférieure à 2 mm. Il peut être utilisé seul ou mélangé à de la poudre de carbone, la quantité totale optimale pour le traitement étant comprise entre 6 et 8 kg/t d'acier.The calcium carbide is preferably a technical calcium carbide with at least 75% pure carbide and a particle size of less than 2 mm. It can be used alone or mixed with carbon powder, the total optimal quantity for treatment being between 6 and 8 kg / t of steel.
Description de l'invention La poudre de carbure de calcium peut remplacer totalement ou partiellement la poudre de graphite ou d'anthracite, mais, pour obtenir un effet sensible sur le perte en fer ou sur la consommation électrique, il faut en utihser au moins 3 kg par tonne d'acier liquide. Quand il est utilisé seul, on constate qu'une substitution à poids égal du carbone par le carbure de calcium donne un bon résultat. Ceci est tout à fait surprenant puisque la quantité conduisant au même dégagement de CO serait 2,7 fois plus importante. Sachant qu'on utilise habituellement de 6 à 8 kg/t de poudre de carbone pour obtenir un laitier moussant, on peut avantageusement utihser la même quantité pondérale de carbure en substitution. Le carbure utilisé est, comme pour les autres applications sidérurgiques, du carbure dit « technique », c'est à dire du carbure résultant de la réduction carbothermique de la chaux au four électrique et contenant de 15 à 35% en poids de chaux résiduelle. Il est préférable que la teneur en carbure soit supérieure à 75%. La granulométrie est choisie de préférence en dessous de 2 τnm3 c'est à dire beaucoup moins que celle du carbure utilisé pour l'affinage en poche, généralement comprise entre 5 et 15 mm. On peut également ajouter à la poudre de carbure des poussières d'aspiration du four électrique.Description of the invention Calcium carbide powder can completely or partially replace graphite or anthracite powder, but to obtain a significant effect on iron loss or electrical consumption, it is necessary to use at least 3 kg per tonne of liquid steel. When it is used alone, it is found that a substitution for equal weight of carbon by calcium carbide gives a good result. This is quite surprising since the amount leading to the same release of CO would be 2.7 times greater. Knowing that usually 6 to 8 kg / t of carbon powder is used to obtain a foaming slag, it is advantageous to use the same amount by weight of carbide in substitution. The carbide used is, as for other steel applications, so-called “technical” carbide, that is to say carbide resulting from the carbothermic reduction of lime in an electric oven and containing from 15 to 35% by weight of residual lime. It is preferable that the carbide content is more than 75%. The particle size is preferably chosen below 2 τnm 3, that is to say much less than that of the carbide used for ladle refining, generally between 5 and 15 mm. It is also possible to add to the carbide powder suction dust from the electric oven.
L'injection de la poudre de carbure doit être accompagnée, comme celle de carbone, d'une injection concomittante d'oxygène pour obtenir un effet exothermique favorable aux différentes réactions, mais on maintient de préférence un certain défaut d'oxygène par rapport à la pratique courante.The injection of the carbide powder must be accompanied, like that of carbon, by a concomitant injection of oxygen to obtain an exothermic effect favorable to the various reactions, but preferably a certain lack of oxygen is maintained with respect to the common practice.
Le laitier doit rester fortement agité pour permettre un transfert thermique rapide et l'élimination de la guangue formée en surface des grains de carbure. La réaction d'oxydation du carbure peut alors se poursuivre jusqu'à sa disparition totale du laitier et celle du carbone peut avoir heu. L'injection du carbure se fait dans les mêmes conditions que celles du carbone, à l'aide d'une lance dont F extrémité se situe soit dans le laitier, soit juste au dessus, soit à l'interface métal-laitier. La substitution d'un poids sensiblement égal de carbure de calcium technique au carbone pour le moussage du laitier de four électrique présente de nombreux avantages. La teneur en FeO du laitier est inférieure de 10% environ, ce qui, pour une quantité de laitier de l'ordre de 120 kg/t, induit une diminution de 12 kg/t de FeO dans le laitier, soit un gain de 9 kg de fer (environ 1%), sans compter le fait qu'on peut diminuer la quantité de laitier utilisé. La consommation d'électricité, à quantité égale d'oxygène injecté, est réduite de l'ordre de 20 kWh par tonne, ce qui entraîne en plus une réduction de la consommation d'électrode et une réduction de la durée sous tension, conduisant à une réduction correspondante du temps entre 2 mises sous tension (« tap to tap »). Si l'exploitant n'est pas intéressé par une augmentation de la productivité, il peut choisir de réduire la quantité d'oxygène injecté, ce qui réduit le coût-matière et l'énergie d'injection.The slag must remain strongly agitated to allow rapid heat transfer and the elimination of the guangue formed on the surface of the carbide grains. The oxidation reaction of the carbide can then continue until its complete disappearance from the slag and that of the carbon can take place. The carbide is injected under the same conditions as that of carbon, using a lance whose end is located either in the slag, or just above, or at the metal-slag interface. The substitution of a substantially equal weight of technical calcium carbide for carbon for the foaming of slag from an electric furnace has many advantages. The FeO content of the slag is approximately 10% lower, which, for a quantity of slag of the order of 120 kg / t, induces a reduction of 12 kg / t of FeO in the slag, ie a gain of 9 kg of iron (about 1%), not to mention the fact that the quantity of slag used can be reduced. The consumption of electricity, with an equal amount of oxygen injected, is reduced by around 20 kWh per tonne, which also leads to a reduction in electrode consumption and a reduction in the duration under voltage, leading to a corresponding reduction in the time between 2 power-ups ("tap to tap"). If the operator is not interested in an increase in productivity, he can choose to reduce the quantity of oxygen injected, which reduces the material cost and the energy of injection.
Le fait de travailler avec un laitier à plus faible teneur en FeO conduit à une réduction de la consommation de réfractaires et de désoxydants en poche. Enfin, on peut diminuer la quantité de chaux apportée pour la formation du laitier, puisque la décomposition du carbure donne de la chaux. L'ensemble de ces avantages conduit ainsi à un bilan économique très favorable.The fact of working with a slag with a lower FeO content leads to a reduction in the consumption of refractories and deoxidizers in the bag. Finally, we can reduce the amount of lime brought in for slag formation, since the decomposition of carbide gives lime. All of these advantages thus lead to a very favorable economic balance.
Le procédé de traitement selon l'invention s'applique non seulement aux aciers ordinaires, mais également aux aciers alliés, en particulier les aciers inoxydables, élaborés au four électrique.The treatment method according to the invention applies not only to ordinary steels, but also to alloy steels, in particular stainless steels, produced in an electric oven.
ExempleExample
Une série de 10 mesures comparatives ont été réahsées sur un four électrique à arc industriel de 130 t de capacité, avec une charge constituée de 70% (en poids) de fer préréduit et de 30% de ferrailles. La durée de traitement a été de 55 mn. Les résultats sont les suivants, en moyenne et rapportés à la tonne d'acier liquide:A series of 10 comparative measurements were carried out on an industrial arc electric oven of 130 t capacity, with a load made up of 70% (by weight) of pre-reduced iron and 30% of scrap. The duration of treatment was 55 min. The results are as follows, on average and related to the ton of liquid steel:
Avec l'injection de carbure de calcium, on constate un moussage du laitier comparable avec la technique antérieure et plutôt mieux stabihsé. Le laitier avant coulée ne contient plus de carbure de calcium. With the injection of calcium carbide, there is a foaming of the slag comparable with the prior art and rather better stabilized. The slag before pouring no longer contains calcium carbide.
Claims
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP97945920A EP1185715A2 (en) | 1996-11-14 | 1997-11-13 | Method for treating steel in an electric arc furnace for obtaining a foamed slag |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR9614103A FR2755700B1 (en) | 1996-11-14 | 1996-11-14 | PROCESS FOR TREATING STEEL IN AN ELECTRIC ARC OVEN TO OBTAIN A FOAMED MILK |
| FR96/14103 | 1996-11-14 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| WO1998021374A2 true WO1998021374A2 (en) | 1998-05-22 |
| WO1998021374A3 WO1998021374A3 (en) | 2001-11-08 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/FR1997/002041 Ceased WO1998021374A2 (en) | 1996-11-14 | 1997-11-13 | Method for treating steel in an electric arc furnace for obtaining a foamed slag |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP1185715A2 (en) |
| FR (1) | FR2755700B1 (en) |
| WO (1) | WO1998021374A2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108410535A (en) * | 2018-04-17 | 2018-08-17 | 太原理工大学 | A kind of sludge microvesicle excitation fuel and preparation method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4911287B1 (en) * | 1970-07-11 | 1974-03-15 | ||
| JPS50113409A (en) * | 1974-06-12 | 1975-09-05 | ||
| US4447265A (en) * | 1983-06-27 | 1984-05-08 | Schwer John W | Method and composition for foaming slag in electric arc furnace |
| DD238170A3 (en) * | 1983-10-05 | 1986-08-13 | Joachim Jansen | METHOD FOR UTILIZING NON-METAL OXIDE RESIDUES FOR ALLOY PURPOSES |
| US4528035A (en) * | 1984-05-21 | 1985-07-09 | Metro Materials Corporation | Composition and process to create foaming slag cover for molten steel |
| FR2634787B1 (en) * | 1988-08-01 | 1991-11-29 | Siderurgie Fse Inst Rech | PROCESS FOR OBTAINING A FOAMING SLAG IN AN ELECTRIC STEEL FURNACE |
| ATA155793A (en) * | 1993-08-04 | 1996-04-15 | Voest Alpine Ind Anlagen | METHOD FOR PRODUCING A METAL MELT AND SYSTEM FOR IMPLEMENTING THE METHOD |
| EP0655508B1 (en) * | 1993-11-30 | 1998-08-19 | ACCIAI SPECIALI TERNI S.p.a. | Process for using foamed slag in stainless steel production in the electric arc furnace |
-
1996
- 1996-11-14 FR FR9614103A patent/FR2755700B1/en not_active Expired - Fee Related
-
1997
- 1997-11-13 WO PCT/FR1997/002041 patent/WO1998021374A2/en not_active Ceased
- 1997-11-13 EP EP97945920A patent/EP1185715A2/en not_active Ceased
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108410535A (en) * | 2018-04-17 | 2018-08-17 | 太原理工大学 | A kind of sludge microvesicle excitation fuel and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2755700A1 (en) | 1998-05-15 |
| FR2755700B1 (en) | 1998-12-18 |
| EP1185715A2 (en) | 2002-03-13 |
| WO1998021374A3 (en) | 2001-11-08 |
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