CA2519728C - Method for producing foamed slag on high-chromium melts in an electric furnace - Google Patents
Method for producing foamed slag on high-chromium melts in an electric furnace Download PDFInfo
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- CA2519728C CA2519728C CA2519728A CA2519728A CA2519728C CA 2519728 C CA2519728 C CA 2519728C CA 2519728 A CA2519728 A CA 2519728A CA 2519728 A CA2519728 A CA 2519728A CA 2519728 C CA2519728 C CA 2519728C
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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
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0087—Treatment of slags covering the steel bath, e.g. for separating slag from the molten metal
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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
-
- 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
- C21C5/5264—Manufacture of alloyed steels including ferro-alloys
-
- 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
-
- 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
-
- 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
- C21C7/0037—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00 by injecting powdered material
-
- 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
-
- 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
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Analytical Chemistry (AREA)
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
- Vertical, Hearth, Or Arc Furnaces (AREA)
- Manufacture And Refinement Of Metals (AREA)
Abstract
The invention relates to a method for producing foamed slag on high-chromium steel melts in an electric furnace, whereby a mixture consisting of a metal oxide and carbon is introduced into the furnace, the metal oxide in the slag is reduced by the carbon, and the gases created in the slag form bubbles which thus foam up the slag. In order to be able to control the gas formation and thus the foaming process, the mixture consisting of a metal oxide and carbon and optionally an iron carrier is introduced as preforms, such as pellets, which are compressed and/or provided with a binding agent. The gas formation can be controlled in terms of location, type and time, by adjusting the characteristics of the pellets, especially the density and/or compression characteristics thereof.
Description
METHOD FOR PRODUCING FOAMED SLAG ON HIGH-CHROMIUM
MELTS IN AN ELECTRIC ARC FURNACE
The invention concerns a method for producing foamed slag on high-chromium steel melts in an electric arc furnace, wherein a mixture of a metal oxide and carbon is introduced into the furnace, the metal oxide is reduced by the carbon in the slag, and the resulting gases bring about the foaming of the slag by bubble formation.
In the operation of electric arc furnaces, the charge, i.e., mainly scrap, and alloys are melted by the electric arcs of the electrodes, which extend downward into the furnace shell.
The slag fulfils not only its primary function, i.e., the removal of undesirable components from the melt, but also a protective function in the foamed state. In this state, the slag encloses the space between the ends of the electrodes and the surface of the metal and protects the refractory lining of the furnace from radiant energy of the electric arc. Due to the low thermal conductivity of the foamed slag, the radiation of the electric arc towards the wall of the arc furnace is greatly reduced, and thus the energy input into the metal melt is improved.
In the case of nonstainless steels or steels with a low chromium content, the foamed slag is produced by simultaneous injection of carbon and oxygen onto the slag and into the steel bath, respectively. The gas that evolves during the reactions that occur:
MELTS IN AN ELECTRIC ARC FURNACE
The invention concerns a method for producing foamed slag on high-chromium steel melts in an electric arc furnace, wherein a mixture of a metal oxide and carbon is introduced into the furnace, the metal oxide is reduced by the carbon in the slag, and the resulting gases bring about the foaming of the slag by bubble formation.
In the operation of electric arc furnaces, the charge, i.e., mainly scrap, and alloys are melted by the electric arcs of the electrodes, which extend downward into the furnace shell.
The slag fulfils not only its primary function, i.e., the removal of undesirable components from the melt, but also a protective function in the foamed state. In this state, the slag encloses the space between the ends of the electrodes and the surface of the metal and protects the refractory lining of the furnace from radiant energy of the electric arc. Due to the low thermal conductivity of the foamed slag, the radiation of the electric arc towards the wall of the arc furnace is greatly reduced, and thus the energy input into the metal melt is improved.
In the case of nonstainless steels or steels with a low chromium content, the foamed slag is produced by simultaneous injection of carbon and oxygen onto the slag and into the steel bath, respectively. The gas that evolves during the reactions that occur:
2[C] + {02} 2{CO}
2{CO} + {02} 2{COQ}
causes foaming of the slag. In addition, the carbon reduces the ferrous oxide to iron and carbon monoxide according to the equation (FeO) + [C] [Fe] + {CO}.
The foamed slag encases the electrodes and is present as a protective layer between the electric arcs and the furnace wall.
In the case of high-chromium melts, the injected carbon reacts basically as a reducing element of the chromium oxide.
The reactions specified above have little importance in the metal bath. Besides, the content of iron in the slag is too low to guarantee satisfactory foaming of the slag. All together, in the case of high-chromium melts, it is difficult, due to the differences that have been mentioned, to produce a foaming slag in the superheating phase.
For this purpose, EP 0 829 545 B1, which concerns a method for producing a foamed slag on molten stainless steel in an electric arc furnace, proposes that a powder, which consists of a metal oxide, either zinc oxide or lead oxide, and carbon, be introduced into the slag. The oxide contained in the powder is reduced by reaction with the carbon. Bubbles consisting mainly of carbon monoxide are formed in the slag and cause the slag to foam. The powder is introduced into the slag with the aid of an injection medium, for example, nitrogen.
Thus, in accordance with the prior art, the reactive mixture is introduced into the slag or melt as a powder. Due to the relatively large surface area associated with the powdered form, brief, violent reactions occur. Moreover, the reaction is locally limited in the vicinity of the injection device and here especially at the tip of the injection lance in the molten bath.
Proceeding from this type of prior art, the objective of the invention is to develop a method for producing foamed slag on molten high-chromium steels in an electric arc furnace, in which the processes that initiate the foaming reaction occur in a controlled way.
2{CO} + {02} 2{COQ}
causes foaming of the slag. In addition, the carbon reduces the ferrous oxide to iron and carbon monoxide according to the equation (FeO) + [C] [Fe] + {CO}.
The foamed slag encases the electrodes and is present as a protective layer between the electric arcs and the furnace wall.
In the case of high-chromium melts, the injected carbon reacts basically as a reducing element of the chromium oxide.
The reactions specified above have little importance in the metal bath. Besides, the content of iron in the slag is too low to guarantee satisfactory foaming of the slag. All together, in the case of high-chromium melts, it is difficult, due to the differences that have been mentioned, to produce a foaming slag in the superheating phase.
For this purpose, EP 0 829 545 B1, which concerns a method for producing a foamed slag on molten stainless steel in an electric arc furnace, proposes that a powder, which consists of a metal oxide, either zinc oxide or lead oxide, and carbon, be introduced into the slag. The oxide contained in the powder is reduced by reaction with the carbon. Bubbles consisting mainly of carbon monoxide are formed in the slag and cause the slag to foam. The powder is introduced into the slag with the aid of an injection medium, for example, nitrogen.
Thus, in accordance with the prior art, the reactive mixture is introduced into the slag or melt as a powder. Due to the relatively large surface area associated with the powdered form, brief, violent reactions occur. Moreover, the reaction is locally limited in the vicinity of the injection device and here especially at the tip of the injection lance in the molten bath.
Proceeding from this type of prior art, the objective of the invention is to develop a method for producing foamed slag on molten high-chromium steels in an electric arc furnace, in which the processes that initiate the foaming reaction occur in a controlled way.
This objective is achieved by a method in accordance with the present invention.
In one aspect, the present invention resides in a method for producing foamed slag on high-chromium steel melts in an electric arc furnace, wherein a mixture of a metal oxide and carbon is introduced into the furnace, the metal oxide is reduced by the carbon in the slag, and the resulting gases form bubbles in the slag, which thus cause the slag to foam, wherein the mixture of metal oxide and carbon is introduced into the furnace as compressed preforms or preforms provided with a binder, wherein density of the preforms is adjusted by compression pressure and a type and quantity of an added iron carrier so that the preforms are heavier than the slag but lighter than the metal melt and float in the slag near a phase boundary between the metal melt and the slag.
In accordance with the invention, the furnace is charged with a mixture of a metal oxide and carbon, not as a powder but rather as compressed preforms and/or preforms provided with a binder. In addition to the preferred pelletized form, it is possible to use other forms, for example, the briquet form. The systematic adjustment of the properties of the preforms, hereinafter referred to in terms of their embodiment as pellets, makes it possible, in contrast to use in powdered form, to control the evolution of gas with respect to location, type, and time -- especially the starting point with respect to time, the rate, the intensity of the reaction, and/or the duration of the reaction.
In particular, the density properties of the pellets are adjusted by the compression pressure and/or the type and amount of an admixed iron carrier, for example, ferronickel, and a binder. In this regard, in accordance with a preferred variant, the density of the compressed preforms is adjusted in such a way that the pellets float in the slag near or directly on the metal-slag phase boundary itself. The addition of the iron 4a carrier ensures that the pellets are heavier than the slag but lighter than the metal melt. The evolution of gas thus occurs in a locally well-defined way, namely, in the slag at the boundary between the metal and slag. In this way, there is no contact between pellets and metal bath, so that carburization of the melt is prevented. It is also possible to adjust the pellet properties in such a way that the pellets can occupy different positions between the molten bath and the slag. This guarantees that the processes that initiate the foaming occur only in the slag, so that the effectiveness is increased.
Furthermore, the pellets should have a density or a degree of compaction that causes them to disintegrate uniformly and slowly, so that the foaming reaction occurs uniformly and over a relatively long period of time. In addition, it is possible to cause the reactions to occur with a time delay by using even higher pressure compaction. This prevents the reaction from occurring too soon and guarantees that the reaction will not start until the pellets are distributed in the slag.
In addition, the evolution of gas can be systematically adjusted by the size of the pellets. As a result of the fact that the pellets have a relatively large diameter and thus a smaller specific surface than powders, the foaming reaction can be maintained for relatively long periods of time with uniform gas evolution.
The basic components metal (Me) oxide and carbon are involved in the following reactions:
(Me,;Oõ) + [C] x[Mel + {CO}
2{CO} + {02} 2{CO2}
Waste products of steel production can be used for the mixture for producing the pellets, such as carbon from consumed electrodes or pieces of waste scale. The use of binders is advisable especially with mixtures of this type.
Aside from the basic components metal oxide and carbon, a flux, especially limestone, is additionally pressed into the proposed pelletized form. The desired CO/CO2 formation is additionally intensified by the limestone.
Furthermore, a slag thinner, preferably CaF2, can be additionally pressed into or bound with the mixture. This counteracts the tendency of chromium-containing slags to become increasingly viscous with increasing chromium oxide content.
It is also advisable to press a reducing agent, such as silicon and/or aluminum, into some of the pellets, especially together with limestone, to control the chromium oxide content of the slag. These reducing agents reduce the chromium oxide contained in the slag and thus lower the chromium content of the slag. In addition, the foaming of the slag is improved.
In contrast to powder, which must be locally injected, the pellets are added in various parts of the furnace through the furnace roof and/or the sidewalls of the furnace. This is not possible with powder, because large fractions of the powder would be sucked out by the dust removal system of the furnace.
It is also advisable to introduce the pellets into the slag in a directed way in the vicinity of and directly at the hot spots of the electrodes to allow the foaming process to occur especially at the electrodes.
Additional details and advantages of the invention are specified in the following description of the drawings.
-- Figure 1 shows a schematic representation of the cross section of an electric arc furnace with charging devices for the slag-foaming pellets.
-- Figure 2 shows the furnace in Figure 1 from above.
The electric arc furnace 1 shown in Figure 1 comprises a furnace shell 2 with a refractory wall 3 and a furnace roof 4.
After the furnace has been charged with scrap and alloying components, three electrodes (in the present case) 5a-c are lowered into the interior of the furnace. The solid material is melted down by the electric arcs that are produced. A slag layer 7 is formed and floats on the melt. To initiate a foaming reaction of the slag 7 between the electrodes 5a-c and the refractory furnace wall 3, slag-foaming material is introduced into the interior of the furnace as preforms 8, namely, in the form of pellets. The pellets are preferably charged through the furnace roof 4, specifically, through the fifth roof hole 9, and/or the sidewalls 10. Injection systems with injection lines or gravity feed systems 11 that extend through the sidewalls 10 of the furnace are provided for this purpose. Instead of injection lines, it is also possible to use injection lances.
Alternatively or additionally, a pneumatic conveyance system 12 consisting of closed circular pipelines is also suitable for charging the pellets. This system has a closed circular pipeline 13 that runs along the roof 4, as shown in Figure 2, which at the same time also has closed circular pipeline segments 14 that run radially to the roof. Three charging holes 15a-c (in the illustrated example) are provided in the closed circular pipelines 13, 14 and the corresponding roof wall. The pellets are introduced into the furnace slag 7 uniformly over the cross section of the furnace by this system 12. In this regard, the charging holes 15a-c are arranged in such a way that the pellets react with the slag 7 in the vicinity of the hot spots.
The pellets float in the slag 7, where they react to produce the desired gas evolution and thus foaming reaction in a way that is controlled with respect to location, time, and type.
In particular, the adjustment of the density and size of the pellets makes it possible to ensure that the gas evolution process proceeds as uniformly as possible, for a relatively long time and not too violently. A controlled reaction at the surface of the pellets results in uniform foaming of the slag.
List of Reference Numbers 1 electric arc furnace 2 furnace shell 3 refractory wall 4 furnace roof 5a-c electrodes 6 melt 7 slag 8 preforms (pellets) 9 fifth roof hole sidewalls of the furnace 11 injection line 12 pneumatic conveyance system 13 closed circular pipeline 14 sections of closed circular pipeline 15a-c charging holes
In one aspect, the present invention resides in a method for producing foamed slag on high-chromium steel melts in an electric arc furnace, wherein a mixture of a metal oxide and carbon is introduced into the furnace, the metal oxide is reduced by the carbon in the slag, and the resulting gases form bubbles in the slag, which thus cause the slag to foam, wherein the mixture of metal oxide and carbon is introduced into the furnace as compressed preforms or preforms provided with a binder, wherein density of the preforms is adjusted by compression pressure and a type and quantity of an added iron carrier so that the preforms are heavier than the slag but lighter than the metal melt and float in the slag near a phase boundary between the metal melt and the slag.
In accordance with the invention, the furnace is charged with a mixture of a metal oxide and carbon, not as a powder but rather as compressed preforms and/or preforms provided with a binder. In addition to the preferred pelletized form, it is possible to use other forms, for example, the briquet form. The systematic adjustment of the properties of the preforms, hereinafter referred to in terms of their embodiment as pellets, makes it possible, in contrast to use in powdered form, to control the evolution of gas with respect to location, type, and time -- especially the starting point with respect to time, the rate, the intensity of the reaction, and/or the duration of the reaction.
In particular, the density properties of the pellets are adjusted by the compression pressure and/or the type and amount of an admixed iron carrier, for example, ferronickel, and a binder. In this regard, in accordance with a preferred variant, the density of the compressed preforms is adjusted in such a way that the pellets float in the slag near or directly on the metal-slag phase boundary itself. The addition of the iron 4a carrier ensures that the pellets are heavier than the slag but lighter than the metal melt. The evolution of gas thus occurs in a locally well-defined way, namely, in the slag at the boundary between the metal and slag. In this way, there is no contact between pellets and metal bath, so that carburization of the melt is prevented. It is also possible to adjust the pellet properties in such a way that the pellets can occupy different positions between the molten bath and the slag. This guarantees that the processes that initiate the foaming occur only in the slag, so that the effectiveness is increased.
Furthermore, the pellets should have a density or a degree of compaction that causes them to disintegrate uniformly and slowly, so that the foaming reaction occurs uniformly and over a relatively long period of time. In addition, it is possible to cause the reactions to occur with a time delay by using even higher pressure compaction. This prevents the reaction from occurring too soon and guarantees that the reaction will not start until the pellets are distributed in the slag.
In addition, the evolution of gas can be systematically adjusted by the size of the pellets. As a result of the fact that the pellets have a relatively large diameter and thus a smaller specific surface than powders, the foaming reaction can be maintained for relatively long periods of time with uniform gas evolution.
The basic components metal (Me) oxide and carbon are involved in the following reactions:
(Me,;Oõ) + [C] x[Mel + {CO}
2{CO} + {02} 2{CO2}
Waste products of steel production can be used for the mixture for producing the pellets, such as carbon from consumed electrodes or pieces of waste scale. The use of binders is advisable especially with mixtures of this type.
Aside from the basic components metal oxide and carbon, a flux, especially limestone, is additionally pressed into the proposed pelletized form. The desired CO/CO2 formation is additionally intensified by the limestone.
Furthermore, a slag thinner, preferably CaF2, can be additionally pressed into or bound with the mixture. This counteracts the tendency of chromium-containing slags to become increasingly viscous with increasing chromium oxide content.
It is also advisable to press a reducing agent, such as silicon and/or aluminum, into some of the pellets, especially together with limestone, to control the chromium oxide content of the slag. These reducing agents reduce the chromium oxide contained in the slag and thus lower the chromium content of the slag. In addition, the foaming of the slag is improved.
In contrast to powder, which must be locally injected, the pellets are added in various parts of the furnace through the furnace roof and/or the sidewalls of the furnace. This is not possible with powder, because large fractions of the powder would be sucked out by the dust removal system of the furnace.
It is also advisable to introduce the pellets into the slag in a directed way in the vicinity of and directly at the hot spots of the electrodes to allow the foaming process to occur especially at the electrodes.
Additional details and advantages of the invention are specified in the following description of the drawings.
-- Figure 1 shows a schematic representation of the cross section of an electric arc furnace with charging devices for the slag-foaming pellets.
-- Figure 2 shows the furnace in Figure 1 from above.
The electric arc furnace 1 shown in Figure 1 comprises a furnace shell 2 with a refractory wall 3 and a furnace roof 4.
After the furnace has been charged with scrap and alloying components, three electrodes (in the present case) 5a-c are lowered into the interior of the furnace. The solid material is melted down by the electric arcs that are produced. A slag layer 7 is formed and floats on the melt. To initiate a foaming reaction of the slag 7 between the electrodes 5a-c and the refractory furnace wall 3, slag-foaming material is introduced into the interior of the furnace as preforms 8, namely, in the form of pellets. The pellets are preferably charged through the furnace roof 4, specifically, through the fifth roof hole 9, and/or the sidewalls 10. Injection systems with injection lines or gravity feed systems 11 that extend through the sidewalls 10 of the furnace are provided for this purpose. Instead of injection lines, it is also possible to use injection lances.
Alternatively or additionally, a pneumatic conveyance system 12 consisting of closed circular pipelines is also suitable for charging the pellets. This system has a closed circular pipeline 13 that runs along the roof 4, as shown in Figure 2, which at the same time also has closed circular pipeline segments 14 that run radially to the roof. Three charging holes 15a-c (in the illustrated example) are provided in the closed circular pipelines 13, 14 and the corresponding roof wall. The pellets are introduced into the furnace slag 7 uniformly over the cross section of the furnace by this system 12. In this regard, the charging holes 15a-c are arranged in such a way that the pellets react with the slag 7 in the vicinity of the hot spots.
The pellets float in the slag 7, where they react to produce the desired gas evolution and thus foaming reaction in a way that is controlled with respect to location, time, and type.
In particular, the adjustment of the density and size of the pellets makes it possible to ensure that the gas evolution process proceeds as uniformly as possible, for a relatively long time and not too violently. A controlled reaction at the surface of the pellets results in uniform foaming of the slag.
List of Reference Numbers 1 electric arc furnace 2 furnace shell 3 refractory wall 4 furnace roof 5a-c electrodes 6 melt 7 slag 8 preforms (pellets) 9 fifth roof hole sidewalls of the furnace 11 injection line 12 pneumatic conveyance system 13 closed circular pipeline 14 sections of closed circular pipeline 15a-c charging holes
Claims (12)
1. Method for producing foamed slag (7) on high-chromium steel melts (6) in an electric arc furnace (1), wherein a mixture of a metal oxide and carbon is introduced into the furnace (1), the metal oxide is reduced by the carbon in the slag (7), and the resulting gases form bubbles in the slag, which thus cause the slag to foam, wherein the mixture of metal oxide and carbon is introduced into the furnace as compressed preforms (8) or preforms (8) provided with a binder, wherein density of the preforms (8) is adjusted by compression pressure and a type and quantity of an added iron carrier so that the preforms are heavier than the slag (7) but lighter than the metal melt (6) and float in the slag near a phase boundary between the metal melt (6) and the slag (7).
2. Method in accordance with Claim 1, wherein the density of the preforms (8) is adjusted by compacting the preforms (8) so that the preforms disintegrate uniformly and slowly, whereby an evolution of gas in the slag (7) occurs uniformly and over a relatively long period of time.
3. Method in accordance with Claim 1, wherein the density of the preforms (8) is adjusted by compacting the preforms (8) so that the preforms disintegrate with a time delay.
4. Method in accordance with Claim 1, wherein a flux is additionally added to the mixture.
5. Method in accordance with Claim 1, wherein a slag thinner is additionally added to the mixture.
6. Method in accordance with Claim 1, wherein a reducing agent is additionally added to the mixture.
7. Method in accordance with Claim 1, wherein the preforms (8) are introduced through the sidewalls (10) and the furnace roof (4) of the electric arc furnace (1).
8. Method in accordance with Claim 1, wherein the preforms (8) are introduced into the slag (7) in a directed way in the vicinity of or directly at the hot spots of the electrodes (5a-c).
9. Method in accordance with Claim 4, wherein the flux comprises limestone.
10. Method in accordance with Claim 5, wherein the slag thinner comprises CaF2.
11. Method in accordance with Claim 6, wherein the reducing agent comprises at least one of silicon and aluminum.
12
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE10323505A DE10323505A1 (en) | 2003-05-24 | 2003-05-24 | Process for producing a foam slag on high-chromium melts in an electric furnace |
| DE10323505.1 | 2003-05-24 | ||
| PCT/EP2004/004312 WO2004104232A1 (en) | 2003-05-24 | 2004-04-23 | Method for producing foamed slag on high-chromium melts in an electric furnace |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2519728A1 CA2519728A1 (en) | 2004-12-02 |
| CA2519728C true CA2519728C (en) | 2011-06-14 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2519728A Expired - Fee Related CA2519728C (en) | 2003-05-24 | 2004-04-23 | Method for producing foamed slag on high-chromium melts in an electric furnace |
Country Status (13)
| Country | Link |
|---|---|
| US (2) | US20060260435A1 (en) |
| EP (1) | EP1629126B1 (en) |
| JP (1) | JP4701331B2 (en) |
| KR (1) | KR101174691B1 (en) |
| CN (2) | CN1795277A (en) |
| CA (1) | CA2519728C (en) |
| DE (1) | DE10323505A1 (en) |
| MY (1) | MY146471A (en) |
| RU (1) | RU2343208C2 (en) |
| TW (1) | TWI295690B (en) |
| UA (1) | UA84151C2 (en) |
| WO (1) | WO2004104232A1 (en) |
| ZA (1) | ZA200505659B (en) |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102006004532B4 (en) | 2006-02-01 | 2014-10-09 | Sms Siemag Aktiengesellschaft | Process for producing a foamed slag in a metallic melt |
| DE102007006529A1 (en) * | 2007-02-09 | 2008-08-14 | Sms Demag Ag | Process and reduction of a chromium-containing slag in an electric arc furnace |
| DE102007050478A1 (en) | 2007-10-23 | 2009-04-30 | Sms Demag Ag | Process for stainless steel production with direct reduction furnaces for ferrochrome and ferronickel on the primary side of a converter |
| DE102008028011A1 (en) * | 2008-06-09 | 2009-12-10 | Sms Siemag Aktiengesellschaft | Process for producing a foamed slag on austenitic stainless melts in an electric arc furnace |
| DE102008032975A1 (en) * | 2008-07-07 | 2010-01-14 | Sms Siemag Aktiengesellschaft | Process for producing foamed slag |
| DE102009020494A1 (en) | 2009-05-08 | 2010-11-11 | Sms Siemag Ag | A method of slag foaming a non-stainless steel melt in an electric arc furnace |
| DE102009043639A1 (en) | 2009-09-29 | 2011-03-31 | Sms Siemag Aktiengesellschaft | Method and apparatus for controlling the production of a foamed slag in a metallic melt |
| DE102010004983A1 (en) * | 2010-01-19 | 2011-07-21 | SMS Siemag Aktiengesellschaft, 40237 | Process for the production of foam slag of a stainless melt in a converter |
| DE102010022692A1 (en) | 2010-03-17 | 2011-09-22 | Sms Siemag Ag | Briquette for producing a foamed slag effect in stainless steel EAF technology |
| KR101229899B1 (en) * | 2010-12-22 | 2013-02-05 | 주식회사 포스코 | Material for promoting slag forming |
| KR101499200B1 (en) * | 2013-06-27 | 2015-03-05 | 현대제철 주식회사 | Furnace |
| EP3034633B1 (en) * | 2014-12-17 | 2017-03-15 | Refractory Intellectual Property GmbH & Co. KG | Mixture, use of this mixture as well as method for conditioning a slag on molten metal from the processing of iron and steel in a metallurgical vessel |
| CN104726636A (en) * | 2015-03-30 | 2015-06-24 | 山西太钢不锈钢股份有限公司 | Foaming agent for smelting stainless steel employing electric furnace and foaming method for foaming agent |
| JP6620781B2 (en) * | 2017-05-15 | 2019-12-18 | Ｊｆｅスチール株式会社 | Dust smelting reduction method and reuse method |
| CN114317885B (en) * | 2022-01-11 | 2022-11-22 | 安徽工业大学 | Biomass electric furnace foaming agent and preparation method and application method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3807986A (en) * | 1971-06-09 | 1974-04-30 | Lukens Steel Co | Combination iron and iron oxide briquette and method of using |
| US3843767A (en) * | 1972-03-27 | 1974-10-22 | Du Pont | Process for treating fluophosphate ores |
| US3925060A (en) * | 1974-09-23 | 1975-12-09 | Timken Co | Compact containing iron oxide and carbon and method for its use in steelmaking |
| JPH04131314A (en) * | 1990-09-21 | 1992-05-06 | Nippon Stainless Steel Co Ltd | Method for recovering valuable metal from byproduct at the time of manufacturing stainless steel |
| 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 |
| FR2753205B1 (en) | 1996-09-12 | 1998-12-04 | Usinor Sacilor | PROCESS FOR PRODUCING A FOAMING SLAG OVER A STAINLESS STEEL MELTING IN AN ELECTRIC OVEN |
| JPH11302712A (en) * | 1998-04-16 | 1999-11-02 | Tetsugen Corp | Reduction dissolution refining method for iron oxide |
| SE512757C2 (en) | 1998-09-03 | 2000-05-08 | Uddeholm Technology Ab | Addition of doping agents in the manufacture of steel in arc furnaces, doping agents and their use |
| US6214085B1 (en) * | 1999-02-01 | 2001-04-10 | Calderon Energy Company Of Bowling Green, Inc. | Method for direct steelmaking |
| LU90409B1 (en) * | 1999-06-25 | 2001-01-02 | Wurth Paul Sa | Proc-d- for optimizing the operation of an electric furnace of the - submerged arc- type |
| LU90481B1 (en) | 1999-12-01 | 2001-06-05 | Wurth Paul Sa | Post-treatment process for metallurgical slag |
-
2003
- 2003-05-24 DE DE10323505A patent/DE10323505A1/en not_active Withdrawn
-
2004
- 2004-04-22 TW TW093111178A patent/TWI295690B/en not_active IP Right Cessation
- 2004-04-23 EP EP04729075A patent/EP1629126B1/en not_active Expired - Lifetime
- 2004-04-23 CA CA2519728A patent/CA2519728C/en not_active Expired - Fee Related
- 2004-04-23 RU RU2005140564/02A patent/RU2343208C2/en not_active IP Right Cessation
- 2004-04-23 CN CNA2004800143226A patent/CN1795277A/en active Pending
- 2004-04-23 US US10/557,190 patent/US20060260435A1/en not_active Abandoned
- 2004-04-23 JP JP2006529704A patent/JP4701331B2/en not_active Expired - Fee Related
- 2004-04-23 UA UAA200512440A patent/UA84151C2/en unknown
- 2004-04-23 WO PCT/EP2004/004312 patent/WO2004104232A1/en active Application Filing
- 2004-04-23 CN CN201110027012XA patent/CN102061356A/en active Pending
- 2004-05-20 MY MYPI20041932A patent/MY146471A/en unknown
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2005
- 2005-07-14 ZA ZA200505659A patent/ZA200505659B/en unknown
- 2005-11-23 KR KR1020057022381A patent/KR101174691B1/en active IP Right Grant
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2012
- 2012-09-12 US US13/611,671 patent/US20130000446A1/en not_active Abandoned
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| MY146471A (en) | 2012-08-15 |
| TW200427844A (en) | 2004-12-16 |
| CN1795277A (en) | 2006-06-28 |
| TWI295690B (en) | 2008-04-11 |
| RU2005140564A (en) | 2006-05-10 |
| EP1629126A1 (en) | 2006-03-01 |
| JP2007501900A (en) | 2007-02-01 |
| JP4701331B2 (en) | 2011-06-15 |
| ZA200505659B (en) | 2006-08-30 |
| CA2519728A1 (en) | 2004-12-02 |
| KR101174691B1 (en) | 2012-08-17 |
| DE10323505A1 (en) | 2004-12-09 |
| KR20060004700A (en) | 2006-01-12 |
| US20060260435A1 (en) | 2006-11-23 |
| CN102061356A (en) | 2011-05-18 |
| RU2343208C2 (en) | 2009-01-10 |
| WO2004104232A8 (en) | 2006-03-02 |
| EP1629126B1 (en) | 2013-03-13 |
| US20130000446A1 (en) | 2013-01-03 |
| WO2004104232A1 (en) | 2004-12-02 |
| UA84151C2 (en) | 2008-09-25 |
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