CA2534623C - Electric reducing furnace - Google Patents
Electric reducing furnace Download PDFInfo
- Publication number
- CA2534623C CA2534623C CA 2534623 CA2534623A CA2534623C CA 2534623 C CA2534623 C CA 2534623C CA 2534623 CA2534623 CA 2534623 CA 2534623 A CA2534623 A CA 2534623A CA 2534623 C CA2534623 C CA 2534623C
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- Prior art keywords
- furnace
- charging
- waste gas
- charging device
- submerged arc
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B3/00—Hearth-type furnaces, e.g. of reverberatory type; Tank furnaces
- F27B3/10—Details, accessories, or equipment peculiar to hearth-type furnaces
- F27B3/18—Arrangements of devices for charging
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B11/00—Making pig-iron other than in blast furnaces
- C21B11/10—Making pig-iron other than in blast furnaces in electric furnaces
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B13/00—Making spongy iron or liquid steel, by direct processes
- C21B13/12—Making spongy iron or liquid steel, by direct processes 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
- C21C5/527—Charging of the electric furnace
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B15/00—Obtaining copper
- C22B15/0026—Pyrometallurgy
- C22B15/0054—Slag, slime, speiss, or dross treating
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B4/00—Electrothermal treatment of ores or metallurgical products for obtaining metals or alloys
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B4/00—Electrothermal treatment of ores or metallurgical products for obtaining metals or alloys
- C22B4/08—Apparatus
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B5/00—General methods of reducing to metals
- C22B5/02—Dry methods smelting of sulfides or formation of mattes
- C22B5/10—Dry methods smelting of sulfides or formation of mattes by solid carbonaceous reducing agents
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B7/00—Working up raw materials other than ores, e.g. scrap, to produce non-ferrous metals and compounds thereof; Methods of a general interest or applied to the winning of more than two metals
- C22B7/04—Working-up slag
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
- F27D17/001—Extraction of waste gases, collection of fumes and hoods used therefor
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
- F27D17/008—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases cleaning gases
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D3/00—Charging; Discharging; Manipulation of charge
- F27D3/10—Charging directly from hoppers or shoots
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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
- Y02P10/10—Reduction of greenhouse gas [GHG] emissions
- Y02P10/134—Reduction of greenhouse gas [GHG] emissions by avoiding CO2, e.g. using hydrogen
-
- 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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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Mechanical Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Environmental & Geological Engineering (AREA)
- General Engineering & Computer Science (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Geochemistry & Mineralogy (AREA)
- Vertical, Hearth, Or Arc Furnaces (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
- Manufacture Of Iron (AREA)
- Discharge Heating (AREA)
- Furnace Details (AREA)
Abstract
The invention relates to an electric reducing furnace (1) for carrying out reduction processes, particularly for reducing slag in order to recover metallic constituents. The electric reducing furnace operates with electrical energy that is fed into the furnace interior (Oi) via at least one electrode.
The reducing furnace (1), while having an air-sealed design, comprises a charging opening (3) for charge stock, which is conveyed via a charging device (4), whereby the charging opening also simultaneously serves as a waste gas exhaust opening (3) for the resulting gas.
The reducing furnace (1), while having an air-sealed design, comprises a charging opening (3) for charge stock, which is conveyed via a charging device (4), whereby the charging opening also simultaneously serves as a waste gas exhaust opening (3) for the resulting gas.
Description
TRANSLATION (HM-687PCT):
Translation of WO 2005/022,062A1 (PCT/EP2004/006,687) with Amended Pages Incorporated Therein ELECTRIC REDUCING FURNACE
The invention concerns an electric arc reduction furnace for carrying out reduction processes, especially for reducing slag to recover metallic constituents, by means of electric energy, which is introduced into the interior of the furnace by at least one electrode. The reduction furnace has an opening in the wall or roof of the furnace for charging the charge material and an opening for exhausting the gas that forms during the reduction process from the furnace.
The slag to be purified is charged into the furnace and reduced. The metals charged with the slag are in the form of oxides (e.g., Cu20), sulfides (e.g., Cu2S), and pure metals (e.g., Cu). The oxide constituents are reduced to metals by the addition of a reducing agent. The sulfides and the pure metallic constituents settle on the bottom of the furnace due to their different densities.
In reduction furnaces of this type for reducing or purifying slags, it is well known that the process gas, such as CO, remains partly or entirely in the furnace and is burned.
The CO-containing process gas is burned in the furnace above the melt or slag with air, which is drawn in through suitable openings in the furnace shell or furnace roof, and then cooled to a certain temperature, which is predetermined by the type of downstream dust catcher.
This is associated with the following disadvantages.
First, in the case of partial combustion of the process gas, there is the danger of a CO explosion or the escape of the poisonous CO gas into the furnace house.
Second, due to the combustion of the gases and of gaseous metal vapors in the furnace, there is increased electrode consumption and increased consumption of the reducing agents, such as coke, coal, etc. This in turn results in high energy losses, which can be on the order of 3-5 metric tons of coke per day and 0.5-0.8 kg of electrode material per metric ton of charge. In a furnace installation that purifies about 1,000 metric tons of slag per day, these additional costs amount to US$1,000 to US$1,500 per day.
The production of this additional waste gas by the unwanted combustion of the electrodes and reducing agents necessitates dust catchers designed for larger volumes of waste gas. In addition, the lining in the gas space of the furnace, especially the roof lining, is subjected to strong thermal loads.
Translation of WO 2005/022,062A1 (PCT/EP2004/006,687) with Amended Pages Incorporated Therein ELECTRIC REDUCING FURNACE
The invention concerns an electric arc reduction furnace for carrying out reduction processes, especially for reducing slag to recover metallic constituents, by means of electric energy, which is introduced into the interior of the furnace by at least one electrode. The reduction furnace has an opening in the wall or roof of the furnace for charging the charge material and an opening for exhausting the gas that forms during the reduction process from the furnace.
The slag to be purified is charged into the furnace and reduced. The metals charged with the slag are in the form of oxides (e.g., Cu20), sulfides (e.g., Cu2S), and pure metals (e.g., Cu). The oxide constituents are reduced to metals by the addition of a reducing agent. The sulfides and the pure metallic constituents settle on the bottom of the furnace due to their different densities.
In reduction furnaces of this type for reducing or purifying slags, it is well known that the process gas, such as CO, remains partly or entirely in the furnace and is burned.
The CO-containing process gas is burned in the furnace above the melt or slag with air, which is drawn in through suitable openings in the furnace shell or furnace roof, and then cooled to a certain temperature, which is predetermined by the type of downstream dust catcher.
This is associated with the following disadvantages.
First, in the case of partial combustion of the process gas, there is the danger of a CO explosion or the escape of the poisonous CO gas into the furnace house.
Second, due to the combustion of the gases and of gaseous metal vapors in the furnace, there is increased electrode consumption and increased consumption of the reducing agents, such as coke, coal, etc. This in turn results in high energy losses, which can be on the order of 3-5 metric tons of coke per day and 0.5-0.8 kg of electrode material per metric ton of charge. In a furnace installation that purifies about 1,000 metric tons of slag per day, these additional costs amount to US$1,000 to US$1,500 per day.
The production of this additional waste gas by the unwanted combustion of the electrodes and reducing agents necessitates dust catchers designed for larger volumes of waste gas. In addition, the lining in the gas space of the furnace, especially the roof lining, is subjected to strong thermal loads.
The Japanese document 2000-039,118 A discloses an electric arc reduction furnace for reducing slag. Powdered charge material is introduced by a charging system through a suitable charge opening in the side wall of the furnace at the level of the slag layer and melted down electrically. Gases that form during the reduction, CO gas in particular, are removed by an exhaust system through a separate exhaust line in an opening in the furnace roof.
Proceeding from the prior art, the objective of the invention is to modify an electric arc reduction furnace in such a way that the aforementioned disadvantages are avoided.
The crux of the invention is the realization of a furnace with an air-sealed design in which the charge material, especially liquid slag, is charged through an airtight opening in the furnace, and at the same time the furnace gas is exhausted or drawn off through the same airtight opening in the furnace. In this way, the furnace is provided with optimum protection against unwanted penetration of air. Oxidation of the electrodes and/or the reducing agents is prevented.
In a preferred embodiment of the invention, the charging system, which is preferably designed as a charging chute and extends into the interior of the furnace through the common charge and waste gas exhaust opening, has a cover. This cover is sealed from the furnace shell and formed as a waste gas chimney towards the top.
This embodiment allows the charging of slag with a simultaneous airtight seal and simultaneous prevention of unwanted consumption of electrodes and reducing agents. The cover allows continuous charging, because it is permanently operative. With a furnace mode of operation under a slight positive pressure, the process gas leaves the furnace via the charge opening in the furnace shell through the waste gas chimney formed by the charging chute and its cover.
In principle, however, it is also possible to seal this common opening for charging and gas exhaust by means of a slide gate. However, this can be considered only if charging is not being performed continuously.
The chimney shape of the cover is preferably formed in such a way that the cover of the charging system has a chimney flue for gas exhaust more or less close to the furnace, and that the chimney flue is followed by a post-combustion chamber. Partial combustion of the process gases can occur in this chimney flue, because it is not entirely possible to prevent air from also being drawn into the chimney flue from the charging side through the charging system. However, the entrance of air into the furnace is completely prevented. Specifically, as a result of the chimney effect, air that is drawn in is not drawn into the furnace but rather into the flue formed by the cover. In the combustion chamber that follows the chimney flue, the controlled supply of additional air completes the combustion of the process gases and cools the combusted waste gas to the lower temperatures that are required.
The conveyance of the charge material into the furnace by the charging system in the form of a charging chute is preferably accomplished by gravity or fluid force. However, the invention also includes the possibility of supporting this conveyance by mechanical means, such as vibrators and rotating rolls.
The slags that are used are present mostly in liquid form.
Liquid slags are charged through the common charge and waste gas exhaust opening. Solid, lumpy slag is also charged at the same time. In one embodiment of the reduction furnace, this charge material is charged together with the reducing agent by means of charging tubes that extend into the interior of the furnace through the furnace roof.
In another embodiment, it is also possible to charge solids through the common charge and waste gas exhaust opening. This is advantageous especially for the reducing agent, because the oxide constituents of the slag are then already being intensively mixed with the reducing agent as they are being charged to the furnace.
All together, the following additional advantages are achieved by the invention:
-- reductions of operating expenses of US$300,000 to US$400,000 per year;
-- lower investment costs for the dust catcher, since the waste gas volume arising from the combustion and the cooling air for the coke and electrodes is eliminated;
-- reduced thermal load on the furnace roof due to the elimination of the latent heat, since no combustion occurs in the furnace;
-- a simpler design of the electrode bar, since adjustment of the electrodes is greatly reduced;
-- assurance of a reducing furnace chamber atmosphere, which is advantageous for recovery of the valuable materials, which are present in the form of oxides.
In one aspect, the present invention resides in a submerged arc furnace for carrying out reduction processes by means of electric energy that is introduced into a furnace interior by at least one electrode, the furnace comprising a charging device and a common charging and waste gas aperture for charging material transported by the charging device into the furnace interior, as well as for discharging process gases produced during the reduction process from the furnace interior, wherein the furnace being an airtight construction and the charging device is provided with a cover with one end of said cover sealingly engaging the furnace, the cover comprising a chimney pipe in proximity to the furnace which serves for discharging the gas and is realized in the form of a waste gas chimney, the charging device protruding into the furnace interior through the common charging and waste gas aperture or ending at the aperture, and wherein the charging device consists of a charging chute and the transport of charging material into the furnace is realized via the charging chute with the aid of gravitational force or promoted with mechanical means, the furnace comprising a furnace roof and at least one charging pipe that serves for charging the furnace with at least one of reducing agents and solid slag, wherein the charging pipe protrudes into the furnace interior through the furnace roof, wherein a post-combustion chamber being connected to the chimney pipe downstream thereof.
In a further aspect, the present invention resides in the submerged arc furnace, wherein the post-combustion chamber is connected to an air supply channel for introducing air in a 6a controlled fashion and for realizing a controlled post-combustion of the process gases.
In yet a further aspect, the present invention resides in the submerged arc furnace, wherein the common charging and waste gas aperture is arranged in the furnace wall or in the furnace roof, to which the charging device with the cover is connected in an airtight fashion on an outside of the furnace.
In still yet a further aspect, the present invention resides in the submerged arc furnace, wherein the charging device is operable to charge liquid slag through the common charging and waste gas aperture.
In yet a further aspect, the present invention resides in submerged arc furnace, wherein the charging device is operable to charge solid matter comprising solid slag and a reducing agent through the common charging and waste gas aperture.
In yet a further aspect, the present invention resides in the submerged arc furnace for use in reduction of slag in order to reclaim metallic components.
In yet a further aspect, the present invention resides in the submerged arc furnace, wherein the mechanical means comprise at least one of vibrators and rotating rollers.
The invention is explained in greater detail below with reference to the specific 6b embodiment of the invention illustrated in the sole drawing, which shows a cross section of a schematically indicated reduction furnace wall with an opening that serves simultaneously as a charge and waste gas exhaust opening.
The electric arc reduction furnace 1 is indicated by the furnace wall 2. An electric arc reduction furnace 1 of this type is used, for example, to carry out recycling processes, such as oxidic waste processes, and especially to purify slags for the purpose of recovering metallic constituents. To this end, at least one electrode (not shown) is inserted in the furnace interior Oi, and the charge material is melted down or raised to high temperatures by the electric energy introduced into the furnace, so that the reduction processes can proceed with the aid of the reducing agents that are introduced, such as coal and coke.
The furnace wall 2 has a charge opening 3. A charging system 4, here in the form of a charging chute 5 or slag feed chute, which is supported by a frame 6, extends through the charge opening 3. Slag is charged into the furnace by means of the charging chute 5 (arrow I). At the same time, this opening 3 also serves as an exhaust opening for the process gases that are formed during the reduction, which are designated here as CO
and as {Zn} to reflect the gaseous metal vapors, such as Zn (arrow II). This opening 3 is basically the only waste gas exhaust opening. However, an emergency chimney for the waste gas can be provided for emergencies.
The charging chute 5 is sealed airtight from the furnace wall 2. For this purpose, it is provided with a cover 7 in the form of a metal housing, which extends from the furnace wall 2 to the inlet 8 of the charging chute 5. On the side of the inlet 8, the cover 7 is bent up somewhat to provide room for the charge material. Close to the furnace, a chimney flue 10 extends from an opening 9 in the cover 7 upward and away from the cover 7. In this way, the cover 7 is formed as an exhaust gas chimney in the upward direction.
The chimney flue 10 is followed in the direction of waste gas flow by a post-combustion chamber 11, into which an air supply channel 12 opens for feeding air into the post-combustion chamber 11.
The process will now be explained. Charge material, such as liquid slag, is continuously charged into the furnace interior by means of the charging chute 5 (arrow I). Reducing agent is charged through separate charging tubes in the furnace roof or possibly by the charging chute 5. At the same time, process gases flow through the same opening 3 into the chimney-like cover 7 in the opposite direction (arrow II) from the charging direction. They flow off through the chimney flue (arrow III). Air (arrow IV) that is drawn in along with the charge material is likewise discharged through the chimney flue (arrow V). Partial combustion of the gases can occur in the chimney flue 10 with this air. However, the actual post combustion with a controlled air supply occurs in the downstream post-combustion chamber 11, into which the controlled air supply is fed (arrow VI).
All together, the invention creates a closed electric arc reduction furnace for purifying liquid slags. Its closed construction is a result of the fact that the furnace is provided with only one gas opening, through which liquid slag is charged and the furnace gas is simultaneously drawn off. This prevents any secondary air from penetrating to the interior of the furnace.
List of Reference Symbols 1 electric arc reduction furnace 2 furnace wall 3 charge opening 4 charging system charging chute 6 frame 7 cover 8 inlet 9 opening in the cover chimney flue 11 post-combustion chamber 12 air supply channel Oi furnace interior arrow I slag and reducing agent charge direction arrow II process gas exhaust direction arrow III flow of the process gases through the chimney arrow IV air drawn in from the charging side arrow V discharge through the chimney of the air drawn in from the charging side arrow VI controlled air supply for post combustion
Proceeding from the prior art, the objective of the invention is to modify an electric arc reduction furnace in such a way that the aforementioned disadvantages are avoided.
The crux of the invention is the realization of a furnace with an air-sealed design in which the charge material, especially liquid slag, is charged through an airtight opening in the furnace, and at the same time the furnace gas is exhausted or drawn off through the same airtight opening in the furnace. In this way, the furnace is provided with optimum protection against unwanted penetration of air. Oxidation of the electrodes and/or the reducing agents is prevented.
In a preferred embodiment of the invention, the charging system, which is preferably designed as a charging chute and extends into the interior of the furnace through the common charge and waste gas exhaust opening, has a cover. This cover is sealed from the furnace shell and formed as a waste gas chimney towards the top.
This embodiment allows the charging of slag with a simultaneous airtight seal and simultaneous prevention of unwanted consumption of electrodes and reducing agents. The cover allows continuous charging, because it is permanently operative. With a furnace mode of operation under a slight positive pressure, the process gas leaves the furnace via the charge opening in the furnace shell through the waste gas chimney formed by the charging chute and its cover.
In principle, however, it is also possible to seal this common opening for charging and gas exhaust by means of a slide gate. However, this can be considered only if charging is not being performed continuously.
The chimney shape of the cover is preferably formed in such a way that the cover of the charging system has a chimney flue for gas exhaust more or less close to the furnace, and that the chimney flue is followed by a post-combustion chamber. Partial combustion of the process gases can occur in this chimney flue, because it is not entirely possible to prevent air from also being drawn into the chimney flue from the charging side through the charging system. However, the entrance of air into the furnace is completely prevented. Specifically, as a result of the chimney effect, air that is drawn in is not drawn into the furnace but rather into the flue formed by the cover. In the combustion chamber that follows the chimney flue, the controlled supply of additional air completes the combustion of the process gases and cools the combusted waste gas to the lower temperatures that are required.
The conveyance of the charge material into the furnace by the charging system in the form of a charging chute is preferably accomplished by gravity or fluid force. However, the invention also includes the possibility of supporting this conveyance by mechanical means, such as vibrators and rotating rolls.
The slags that are used are present mostly in liquid form.
Liquid slags are charged through the common charge and waste gas exhaust opening. Solid, lumpy slag is also charged at the same time. In one embodiment of the reduction furnace, this charge material is charged together with the reducing agent by means of charging tubes that extend into the interior of the furnace through the furnace roof.
In another embodiment, it is also possible to charge solids through the common charge and waste gas exhaust opening. This is advantageous especially for the reducing agent, because the oxide constituents of the slag are then already being intensively mixed with the reducing agent as they are being charged to the furnace.
All together, the following additional advantages are achieved by the invention:
-- reductions of operating expenses of US$300,000 to US$400,000 per year;
-- lower investment costs for the dust catcher, since the waste gas volume arising from the combustion and the cooling air for the coke and electrodes is eliminated;
-- reduced thermal load on the furnace roof due to the elimination of the latent heat, since no combustion occurs in the furnace;
-- a simpler design of the electrode bar, since adjustment of the electrodes is greatly reduced;
-- assurance of a reducing furnace chamber atmosphere, which is advantageous for recovery of the valuable materials, which are present in the form of oxides.
In one aspect, the present invention resides in a submerged arc furnace for carrying out reduction processes by means of electric energy that is introduced into a furnace interior by at least one electrode, the furnace comprising a charging device and a common charging and waste gas aperture for charging material transported by the charging device into the furnace interior, as well as for discharging process gases produced during the reduction process from the furnace interior, wherein the furnace being an airtight construction and the charging device is provided with a cover with one end of said cover sealingly engaging the furnace, the cover comprising a chimney pipe in proximity to the furnace which serves for discharging the gas and is realized in the form of a waste gas chimney, the charging device protruding into the furnace interior through the common charging and waste gas aperture or ending at the aperture, and wherein the charging device consists of a charging chute and the transport of charging material into the furnace is realized via the charging chute with the aid of gravitational force or promoted with mechanical means, the furnace comprising a furnace roof and at least one charging pipe that serves for charging the furnace with at least one of reducing agents and solid slag, wherein the charging pipe protrudes into the furnace interior through the furnace roof, wherein a post-combustion chamber being connected to the chimney pipe downstream thereof.
In a further aspect, the present invention resides in the submerged arc furnace, wherein the post-combustion chamber is connected to an air supply channel for introducing air in a 6a controlled fashion and for realizing a controlled post-combustion of the process gases.
In yet a further aspect, the present invention resides in the submerged arc furnace, wherein the common charging and waste gas aperture is arranged in the furnace wall or in the furnace roof, to which the charging device with the cover is connected in an airtight fashion on an outside of the furnace.
In still yet a further aspect, the present invention resides in the submerged arc furnace, wherein the charging device is operable to charge liquid slag through the common charging and waste gas aperture.
In yet a further aspect, the present invention resides in submerged arc furnace, wherein the charging device is operable to charge solid matter comprising solid slag and a reducing agent through the common charging and waste gas aperture.
In yet a further aspect, the present invention resides in the submerged arc furnace for use in reduction of slag in order to reclaim metallic components.
In yet a further aspect, the present invention resides in the submerged arc furnace, wherein the mechanical means comprise at least one of vibrators and rotating rollers.
The invention is explained in greater detail below with reference to the specific 6b embodiment of the invention illustrated in the sole drawing, which shows a cross section of a schematically indicated reduction furnace wall with an opening that serves simultaneously as a charge and waste gas exhaust opening.
The electric arc reduction furnace 1 is indicated by the furnace wall 2. An electric arc reduction furnace 1 of this type is used, for example, to carry out recycling processes, such as oxidic waste processes, and especially to purify slags for the purpose of recovering metallic constituents. To this end, at least one electrode (not shown) is inserted in the furnace interior Oi, and the charge material is melted down or raised to high temperatures by the electric energy introduced into the furnace, so that the reduction processes can proceed with the aid of the reducing agents that are introduced, such as coal and coke.
The furnace wall 2 has a charge opening 3. A charging system 4, here in the form of a charging chute 5 or slag feed chute, which is supported by a frame 6, extends through the charge opening 3. Slag is charged into the furnace by means of the charging chute 5 (arrow I). At the same time, this opening 3 also serves as an exhaust opening for the process gases that are formed during the reduction, which are designated here as CO
and as {Zn} to reflect the gaseous metal vapors, such as Zn (arrow II). This opening 3 is basically the only waste gas exhaust opening. However, an emergency chimney for the waste gas can be provided for emergencies.
The charging chute 5 is sealed airtight from the furnace wall 2. For this purpose, it is provided with a cover 7 in the form of a metal housing, which extends from the furnace wall 2 to the inlet 8 of the charging chute 5. On the side of the inlet 8, the cover 7 is bent up somewhat to provide room for the charge material. Close to the furnace, a chimney flue 10 extends from an opening 9 in the cover 7 upward and away from the cover 7. In this way, the cover 7 is formed as an exhaust gas chimney in the upward direction.
The chimney flue 10 is followed in the direction of waste gas flow by a post-combustion chamber 11, into which an air supply channel 12 opens for feeding air into the post-combustion chamber 11.
The process will now be explained. Charge material, such as liquid slag, is continuously charged into the furnace interior by means of the charging chute 5 (arrow I). Reducing agent is charged through separate charging tubes in the furnace roof or possibly by the charging chute 5. At the same time, process gases flow through the same opening 3 into the chimney-like cover 7 in the opposite direction (arrow II) from the charging direction. They flow off through the chimney flue (arrow III). Air (arrow IV) that is drawn in along with the charge material is likewise discharged through the chimney flue (arrow V). Partial combustion of the gases can occur in the chimney flue 10 with this air. However, the actual post combustion with a controlled air supply occurs in the downstream post-combustion chamber 11, into which the controlled air supply is fed (arrow VI).
All together, the invention creates a closed electric arc reduction furnace for purifying liquid slags. Its closed construction is a result of the fact that the furnace is provided with only one gas opening, through which liquid slag is charged and the furnace gas is simultaneously drawn off. This prevents any secondary air from penetrating to the interior of the furnace.
List of Reference Symbols 1 electric arc reduction furnace 2 furnace wall 3 charge opening 4 charging system charging chute 6 frame 7 cover 8 inlet 9 opening in the cover chimney flue 11 post-combustion chamber 12 air supply channel Oi furnace interior arrow I slag and reducing agent charge direction arrow II process gas exhaust direction arrow III flow of the process gases through the chimney arrow IV air drawn in from the charging side arrow V discharge through the chimney of the air drawn in from the charging side arrow VI controlled air supply for post combustion
Claims (7)
1. A submerged arc furnace for carrying out reduction processes by means of electric energy that is introduced into a furnace interior by at least one electrode, the furnace comprising a charging device and a common charging and waste gas aperture for charging material transported by the charging device into the furnace interior, as well as for discharging process gases produced during the reduction process from the furnace interior, wherein the furnace being an airtight construction and the charging device is provided with a cover with one end of said cover sealingly engaging the furnace, the cover comprising a chimney pipe in proximity to the furnace which serves for discharging the gas and is realized in the form of a waste gas chimney, the charging device protruding into the furnace interior through the common charging and waste gas aperture or ending at the aperture, and wherein the charging device consists of a charging chute and the transport of charging material into the furnace is realized via the charging chute with the aid of gravitational force or promoted with mechanical means, the furnace comprising a furnace roof and at least one charging pipe that serves for charging the furnace with at least one of reducing agents and solid slag, wherein the charging pipe protrudes into the furnace interior through the furnace roof, wherein a post-combustion chamber being connected to the chimney pipe downstream thereof.
2. The submerged arc furnace according to Claim 1, wherein the post-combustion chamber is connected to an air supply channel for introducing air in a controlled fashion and for realizing a controlled post-combustion of the process gases.
3. The submerged arc furnace according to Claim 1 or 2, wherein the common charging and waste gas aperture is arranged in the furnace wall or in the furnace roof, to which the charging device with the cover is connected in an airtight fashion on an outside of the furnace.
4. The submerged arc furnace according to any one of Claims 1 to 3, wherein the charging device is operable to charge liquid slag through the common charging and waste gas aperture.
5. The submerged arc furnace according to any one of Claims 1 to 4, wherein the charging device is operable to charge solid matter comprising solid slag and a reducing agent through the common charging and waste gas aperture.
6. The submerged arc furnace according to any one of Claims 1 to 5 for use in reduction of slag in order to reclaim metallic components.
7. The submerged arc furnace according to any one of Claims 1 to 5, wherein the mechanical means comprise at least one of vibrators and rotating rollers.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE10335847A DE10335847A1 (en) | 2003-07-31 | 2003-07-31 | Electric arc reduction furnace for reducing slag in the recovery of metallic components comprises a charging opening for charging material which simultaneously acts as an exhaust gas line opening for the gas produced |
| DE10335847.1 | 2003-07-31 | ||
| PCT/EP2004/006687 WO2005022062A1 (en) | 2003-07-31 | 2004-06-21 | Electric reducing furnace |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2534623A1 CA2534623A1 (en) | 2005-03-10 |
| CA2534623C true CA2534623C (en) | 2011-11-15 |
Family
ID=34072058
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2534623 Expired - Fee Related CA2534623C (en) | 2003-07-31 | 2004-06-21 | Electric reducing furnace |
Country Status (12)
| Country | Link |
|---|---|
| EP (1) | EP1658467B1 (en) |
| CN (1) | CN100537784C (en) |
| AT (1) | ATE377740T1 (en) |
| AU (1) | AU2004269087B2 (en) |
| BR (1) | BRPI0413109A (en) |
| CA (1) | CA2534623C (en) |
| CL (1) | CL2004001844A1 (en) |
| DE (2) | DE10335847A1 (en) |
| ES (1) | ES2293277T3 (en) |
| MX (1) | MXPA06001136A (en) |
| WO (1) | WO2005022062A1 (en) |
| ZA (1) | ZA200510205B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU2008299386B2 (en) | 2007-09-14 | 2012-01-12 | Barrick Gold Corporation | Process for recovering platinum group metals using reductants |
| IT1396815B1 (en) | 2009-12-04 | 2012-12-14 | Danieli Off Mecc | DEVICE AND PROCEDURE FOR FEEDING METAL MATERIAL IN A MERGER PLANT |
| CA2852500C (en) * | 2012-06-27 | 2015-06-23 | Nippon Steel & Sumitomo Metal Corporation | Reduction processing apparatus for steel-making slag and reduction processing system for steel-making slag |
| CN106403581B (en) * | 2016-11-16 | 2019-06-07 | 攀枝花市仁通钒业有限公司 | With sealed electric arc furnaces filler device |
| RU2677550C2 (en) * | 2017-05-29 | 2019-01-17 | федеральное государственное бюджетное образовательное учреждение высшего образования "Воронежский государственный университет" (ФГБОУ ВО "ВГУ") | Method of using construction wastes as component of slag-forming mixtures |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4836732A (en) * | 1986-05-29 | 1989-06-06 | Intersteel Technology, Inc. | Method and apparatus for continuously charging a steelmaking furnace |
| AT401527B (en) * | 1991-12-20 | 1996-09-25 | Voest Alpine Ind Anlagen | METHOD FOR MELTING SCRAP, AND DEVICE FOR CARRYING OUT THIS METHOD |
| JPH07190629A (en) * | 1993-04-15 | 1995-07-28 | Ishikawajima Harima Heavy Ind Co Ltd | Scrap material preheating and charging device |
| JP2861794B2 (en) * | 1994-03-18 | 1999-02-24 | 日本鋼管株式会社 | Melting furnace with raw material preheating tank |
| JP2003502504A (en) * | 1999-06-23 | 2003-01-21 | エスエムエス・デマーク・アクチエンゲゼルシャフト | Method for recovering chromium metal from slag containing chromium oxide |
| ATE383447T1 (en) * | 2001-09-28 | 2008-01-15 | Jean Davene | INTEGRATED PRODUCTION OF REINFORCED CONCRETE ELEMENTS WITH VALORIZATION OF THE METALLURGICAL SLAG ARISING DURING CONCRETE STEEL PRODUCTION |
-
2003
- 2003-07-31 DE DE10335847A patent/DE10335847A1/en not_active Withdrawn
-
2004
- 2004-06-21 AU AU2004269087A patent/AU2004269087B2/en not_active Ceased
- 2004-06-21 MX MXPA06001136A patent/MXPA06001136A/en active IP Right Grant
- 2004-06-21 DE DE200450005447 patent/DE502004005447D1/en not_active Expired - Lifetime
- 2004-06-21 AT AT04740124T patent/ATE377740T1/en active
- 2004-06-21 CA CA 2534623 patent/CA2534623C/en not_active Expired - Fee Related
- 2004-06-21 BR BRPI0413109 patent/BRPI0413109A/en not_active IP Right Cessation
- 2004-06-21 CN CNB2004800221140A patent/CN100537784C/en not_active Expired - Fee Related
- 2004-06-21 EP EP04740124A patent/EP1658467B1/en not_active Expired - Lifetime
- 2004-06-21 ES ES04740124T patent/ES2293277T3/en not_active Expired - Lifetime
- 2004-06-21 WO PCT/EP2004/006687 patent/WO2005022062A1/en active IP Right Grant
- 2004-07-22 CL CL2004001844A patent/CL2004001844A1/en unknown
-
2005
- 2005-12-14 ZA ZA200510205A patent/ZA200510205B/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| MXPA06001136A (en) | 2006-04-24 |
| CN1829891A (en) | 2006-09-06 |
| BRPI0413109A (en) | 2006-10-03 |
| EP1658467A1 (en) | 2006-05-24 |
| EP1658467B1 (en) | 2007-11-07 |
| CA2534623A1 (en) | 2005-03-10 |
| DE502004005447D1 (en) | 2007-12-20 |
| CN100537784C (en) | 2009-09-09 |
| AU2004269087A1 (en) | 2005-03-10 |
| WO2005022062A1 (en) | 2005-03-10 |
| ATE377740T1 (en) | 2007-11-15 |
| AU2004269087B2 (en) | 2010-05-20 |
| CL2004001844A1 (en) | 2005-05-20 |
| ZA200510205B (en) | 2006-10-25 |
| DE10335847A1 (en) | 2005-02-17 |
| ES2293277T3 (en) | 2008-03-16 |
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| EEER | Examination request | ||
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