EP0946761A1 - Anlage und verfahren zum herstellen von metallschmelzen - Google Patents
Anlage und verfahren zum herstellen von metallschmelzenInfo
- Publication number
- EP0946761A1 EP0946761A1 EP98929118A EP98929118A EP0946761A1 EP 0946761 A1 EP0946761 A1 EP 0946761A1 EP 98929118 A EP98929118 A EP 98929118A EP 98929118 A EP98929118 A EP 98929118A EP 0946761 A1 EP0946761 A1 EP 0946761A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- vessel
- electric arc
- arc furnace
- furnace vessel
- oxygen
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Ceased
Links
Classifications
-
- 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
- F27B3/183—Charging of arc furnaces vertically through the roof, e.g. in three points
- F27B3/186—Charging in a vertical chamber adjacent to the melting chamber
-
- 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
- C21C5/56—Manufacture of steel by other methods
-
- 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
- C21C5/5252—Manufacture of steel in electric furnaces in an electrically heated multi-chamber furnace, a combination of electric furnaces or an electric furnace arranged for associated working with a non electric furnace
-
- 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
- C21C5/56—Manufacture of steel by other methods
- C21C5/567—Manufacture of steel by other methods operating in a continuous way
-
- 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
- F27B3/04—Hearth-type furnaces, e.g. of reverberatory type; Tank furnaces of multiple-hearth type; of multiple-chamber type; Combinations of hearth-type furnaces
- F27B3/045—Multiple chambers, e.g. one of which is used for charging
-
- 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
- F27B3/22—Arrangements of air or gas supply devices
- F27B3/225—Oxygen blowing
-
- 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
-
- 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
-
- 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
- C21C5/56—Manufacture of steel by other methods
- C21C5/562—Manufacture of steel by other methods starting from scrap
-
- 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
- F27B19/00—Combinations of furnaces of kinds not covered by a single preceding main group
- F27B19/04—Combinations of furnaces of kinds not covered by a single preceding main group arranged for associated working
-
- 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 plant for producing metal melts, in particular iron melts, such as steel melts, crude steel melts or pig iron melts, and a method for producing these melts.
- the AC or DC electric arc furnace serves as the standard unit for electric steel production.
- the iron carriers used are made of - 60 to 100% steel scrap, directly reduced iron sponge in various
- liquid and / or solid pig iron melted down with the help of one or more electric arcs using oxygen lance (s) - optionally burner (s), nozzles and / or inert gas flushing - and addition of carbon carriers and slag formers.
- the steel bath is then brought to the temperature and composition desired for tapping in a flat bath period (5 to 10 min) in the electric arc furnace and calmed down when tapping in the pan.
- the energy and material consumption as well as the plant productivity are quite different depending on the respective application conditions and the melting practice.
- the limitations mentioned in the conventional electric arc furnace are caused exclusively by the furnace configuration, which does not allow a quasi-stationary, continuous process.
- the operations charging, melting, freshening, heating up and parting off take place in one place, inevitably more or less staggered and with interruption (s) of the feed and power supply - at least before and during tapping - to the desired composition and temperature (homogeneity and overheating with regard to the liquidus temperature) of the crude steel.
- the current process flow in the electric arc furnace is discontinuous and therefore limited in performance. In this regard, the following should be mentioned:
- AT-B - 295.566 describes a process for the continuous production of steel by melting pre-reduced ore and then refining the melt from semi-steel (semi-steel) to steel in an arc melting furnace with a melting range, to which a fresh zone and at least one slag settling chamber are connected are known in which pre-reduced iron ore is introduced in lump or granular form into the arc zone of the melting furnace, the metal in the furnace is continuously stirred and brought into circulation and the metal by blowing in oxygen-containing gas as it flows through a fresh zone Steel is refurbished, whereas slag is caused to flow along at least part of the length of the fresh zone against the metal.
- a slag settling chamber without intensive bath mixing the slag calms down, which is then tapped from the slag settling chamber.
- scrap and molten pig iron can be used, but only in very limited quantities.
- the exhaust gases are removed directly in the fresh zone, i.e. not via the arc melting furnace.
- the fresh zone is designed as a channel reactor, which results in a high specific surface with high heat losses. Refreshing takes place with a C concentration gradient along the fresh zone of the channel reactor without a concentration compensation vessel, which is why the C content is difficult to adjust or regulate.
- This known method is therefore of limited use and is used primarily to produce crude steel from pre-reduced ore.
- DE-C 3 609 923 discloses a method and a device for the continuous melting of scrap into crude steel.
- this method which is mainly limited to scrap melting (the use of liquid pig iron and / or sponge iron is not mentioned)
- the heat of the furnace gas is used to heat the scrap.
- the scrap is preheated in a shaft placed centrally on the hearth furnace and introduced centrally into the hearth furnace, whereby a scrap column is formed, which is supported on the bottom of the electric arc furnace with the formation of a pouring cone and can reach up to the scrap loading opening in the upper part of the scrap preheating shaft.
- Swiveling electrodes preferably four electrodes
- the angle of inclination between the central electrode axis and a vertical is more than 20 ° for each electrode during scrap melting.
- the stove is exposed to an enormous heat load, since the arcs between the Burn the centrally placed scrap column and the walls or the lid of the stove.
- this leads to increased wear of the refractory lining, and thus to higher material and time costs for carrying out repairs.
- a large part of the energy introduced is transmitted to the furnace walls and the furnace cover by radiation and is lost.
- a possible bridge formation in the scrap column - above the melting caverns melted into it by the electrodes - does not rule out a fall of the scrap column (or parts thereof), which can lead to an electrode breakage and thus to a process interruption.
- the Contiarc process is known from MPT International 2/1996, pages 56 to 60, in which scrap is melted down continuously, etc. in a ring shaft furnace. This process is used only for melting scrap; the use of sponge iron and / or liquid pig iron is not mentioned.
- a disadvantage of this method is the difficulty in setting the crude steel temperature immediately before the start and during the tapping process, since there is a very large contact area of the scrap, which is arranged in a ring, with the liquid bath. Difficulties may also arise with regard to concentration equalization or chemical homogeneity of the melt which has been discontinuously freshly and tapped in this process.
- Consteel- ® (known from Electric Furnace Conference Proceedings 1992, pages 309-313) is preheated with an elongated, horizontal preheating scrap 'and charged into an electric furnace, u.zw. on one side of the electric oven.
- the exhaust gas generated in the electric furnace is removed via the elongated preheating device for the scrap.
- the elongated preheating duct for the scrap is arranged in a stationary manner, whereas the electric furnace is tiltably mounted so that a crude steel tapping can be carried out discontinuously in this process.
- the construction itself is therefore complex, as with all tilting ovens.
- the refractory lining of the furnace is mechanically stressed.
- the scrap is loaded batchwise, since the scrap is only introduced on one side of the furnace, etc. is deposited in an edge area of the furnace.
- the melting process and the mixing process cannot be carried out optimally; the use of burners in the electric furnace to support the scrap melting would only be possible with a low degree of efficiency.
- the dust content in the exhaust gas is relatively high because the exhaust gas is not filtered by the scrap.
- the invention aims to avoid these disadvantages and difficulties and has as its object a plant and a method for producing molten metals.
- iron supports with different physicochemical properties such as scrap iron, liquid and / or solid pig iron, iron carbide, sponge iron, iron ore with different degrees of pre-reduction, sinter, scale, metallurgical dust, dried sludge, etc., etc. in a wide variety of quantities, so that, for example, if one of the iron girders appears to be bottlenecked, it can be switched to another without significant capacity restrictions.
- a system is equipped with the following features:
- An electric arc furnace vessel which is provided with at least one charging opening for a molten metal and / or scrap and / or direct-reduced metal, in particular direct-reduced iron and / or ore, and at least one electrode and at least one slag tapping device,
- the oxygen blowing converter vessel forms a unit connected by an overflow weir with the electric arc furnace vessel
- the bath surface in the oxygen blowing converter vessel which is specific to the bath volume, is smaller than in the electric arc furnace vessel and
- the oxygen blowing converter vessel with the electric arc furnace vessel has a common reaction space above the bath level of these vessels.
- the system according to the invention has the advantage that in the case of continuous parting, or in the case of a discontinuous parting, only slight thermal cycling stresses take place on the refractory lining of the system parts.
- the unit which is preferably rigid compared to the foundation, formed from converter vessel and electric arc furnace vessel, there is no mechanical stress on the vessels, in particular the refractory lining thereof, due to tilting movements or weight displacements caused thereby.
- the refractory lining in the electric arc furnace is protected, since there a C-rich metal melt always has a reducing effect on the slag or reduces the FeO content of the slag.
- the temperature in the electric arc furnace is relatively low, e.g. less than 1600 ° C.
- the tapping metal bath level of the oxygen blowing converter vessel is below the metal bath level of the electric arc furnace vessel, the bottom of the oxygen blowing converter vessel advantageously being arranged at a lower level than the bottom of the electric arc furnace.
- the oxygen blowing converter vessel is preferably equipped with a blowing lance for oxygen or an oxygen-containing gas mixture.
- the oxygen blowing converter vessel is equipped with floor nozzles, preferably with oxygen blowing floor nozzles.
- the electric arc furnace is advantageously equipped with at least one metal tapping device.
- the slag tapping device is expediently provided on a decanter forming a unit with the electric arc furnace vessel, which is preferably diametrically opposite the overflow weir. This enables the slag that forms in the oxygen blowing converter vessel to flow into the electric arc furnace vessel in countercurrent to the molten metal.
- the oxygen-blowing converter vessel and / or the electric-arc furnace vessel are expediently equipped with a charging opening for charging metallic feedstocks, ore, additives, alloys, carburizing agents and the oxygen-blowing converter vessel is also equipped with an oxygen-containing gas or afterburning nozzles and / or Lances equipped, preferably at least one of them in the vicinity of the transition between the two vessels.
- the electric arc furnace vessel is equipped with at least one preheating shaft which supplies fixed iron supports and is arranged above the electric arc furnace vessel and preferably on the side thereof or in a ring above the furnace vessel, as a result of which the introduction of preheated scrap and / or sponge iron or other iron carriers in a simple manner and by utilizing the heat content of the exhaust gases generated in the electric arc furnace vessel.
- the preheating shaft can be arranged centrally or decentrally and is preferably not equipped with gas-permeable shut-off elements (fingers), ie the preheating shaft opens directly and without obstacle into the electric arc furnace vessel.
- the fixed iron supports forming a column at the bottom of the electric arc furnace vessel.
- At least one conveyor belt preferably provided with a housing, opens into the preheating shaft, wherein heating devices, which are designed as afterburning devices and / or burners with lines supplying an oxygen-containing gas, installed in the housing, expediently open into the housing.
- heating devices which are designed as afterburning devices and / or burners with lines supplying an oxygen-containing gas, installed in the housing, expediently open into the housing.
- At least part of the inner surface of the preheating shaft and / or the housing and / or the lid of the electric arc furnace vessel and / or the lid of the oxygen blowing converter vessel is advantageously lined with refractory materials.
- the electric arc furnace vessel is preferably equipped with a device which supplies a molten metal, preferably pig iron.
- the electric arc furnace vessel is equipped with a preheating shaft, which is arranged above the electric arc furnace vessel and opens into the electric arc furnace vessel via a gas-permeable, cooled shut-off device.
- An alternative embodiment is characterized in that the preheating shaft is arranged centrally above the electric arc furnace vessel and the lid of the electric arc furnace vessel is ring-shaped, surrounding the preheating shaft and connecting it with side walls of the electric arc furnace vessel, whereby Electrodes, preferably graphite electrodes, protrude obliquely through the lid into the interior of the electric arc furnace.
- nozzles and / or lances and / or burners opening into the interior of the electric arc furnace vessel are provided, which either connect to an iron carrier feed device and / or an ore feed device and / or a carbon or carbon carrier feed device and / or a slag-forming feed device and / or an oxygen or an oxygen-containing gas feed device and / or a hydrocarbon feed device and / or an inert gas feed device are connected.
- Nozzles and / or lances are advantageously arranged in the oxygen blowing converter, which either connect to an iron carrier feed device and / or an ore feed device and / or a coal or carbon carrier feed device and / or a slag generator feed device and / or an oxygen or an oxygen-containing gas supply device and / or a hydrocarbon supply device and / or an inert gas supply device are connected.
- the nozzles are preferably designed as sub-bath nozzles and / or floor-flushing stones or the lances are arranged to be movable, in particular pivotable and / or movable in their longitudinal direction.
- the electric arc furnace vessel is provided with an approximately centrally arranged electrode (s) projecting into the vessel from above and optionally with a bottom electrode.
- the preheating shaft is preferably designed as a unit that can be separated and exchanged from the electric arc furnace vessel and from the housing.
- the lid of the electric arc furnace vessel and the lid of the oxygen blowing converter vessel form one unit or are designed as one unit.
- At least one inspection and / or repair opening is expediently provided, preferably above the transition from the electric arc furnace vessel to the oxygen-gas converter vessel.
- an advantageous embodiment is characterized in that the oxygen-blowing converter vessel is designed as a removable and replaceable structural unit that can be separated from the electric arc furnace vessel.
- the electric arc furnace vessel is preferably equipped with a bottom that slopes in the direction of the decanter and merges into an approximately horizontal bottom part of the decanter, the deepest point of the bottom being arranged in the decanter and at the lowest point of the bottom of the decanter a metal tap hole is provided.
- a method for producing metal melts, in particular steel melts, such as crude steel melts, is characterized by the combination of the following process steps:
- a premelt is produced in the electric arc furnace vessel and brought to a specific temperature level and to a specific chemical composition
- the premelt flows continuously and irreversibly into the oxygen-blowing converter vessel via the overflow weir,
- the premelt is continuously refined in the oxygen blowing converter vessel, preferably to raw steel and
- the fresh melt is discharged continuously or discontinuously from the oxygen blowing converter vessel,
- a chemical composition and a temperature of the molten metal which correspond to the chemical composition and the temperature of the finished melt or of the end product, which are desired during the tapping, are preferably set in a continuous manner in the oxygen blowing converter vessel.
- the exhaust gases formed in the oxygen blowing converter vessel are advantageously discharged via the electric arc furnace vessel, with a CO + H 2 afterburning being carried out both in the oxygen blowing converter vessel and in the electric arc furnace vessel, the expediently Exhaust gases arising in the electric arc furnace vessel and the exhaust gases flowing over into the electric arc furnace vessel from the oxygen blowing converter vessel are used for preheating the lumpy charging material introduced into the electric arc furnace vessel.
- the exhaust gases used for preheating are gradually burned for better energy utilization during the preheating process.
- a negative pressure is preferably maintained in the electric arc furnace vessel and in the oxygen blowing converter vessel.
- Pig iron in liquid form is charged into the electric arc furnace vessel and brought to a certain temperature level
- the Si and P content is reduced when pre-freshening in the electric arc furnace
- the molten pig iron flows continuously via the overflow weir into the oxygen blowing converter vessel,
- the molten pig iron is also continuously partially refreshed in the oxygen blowing converter vessel,
- the partly freshed pig iron is discharged discontinuously or continuously from the oxygen blowing converter vessel and
- the slag that forms in the oxygen-blowing converter vessel flows in countercurrent into the electric-arc furnace vessel from which it is drawn off, the partially-freshed (pretreated) pig iron expediently in a converter or electric-arc furnace in a conventional manner provided in addition to the system, with or without a feed is finished fresh from other iron carriers to a liquid end product.
- the metallic insert mix is preferably composed of at least one of the following components
- Scrap such as steel scrap, and / or solid pig iron or cast iron
- Direct-reduced iron as pellets and / or briquettes and / or iron carbide
- the metallic insert mix is formed at least from alloyed steel scrap and liquid and / or solid alloying agents and / or ferroalloys.
- the steel melt tapped off from the blast converter converter vessel is preferably further treated as a preliminary melt in a subsequent secondary metallurgical treatment including decarburization, either with or without negative pressure (vacuum).
- the vacuum treatment can be done with a VOD, RH-OB or a KTB system.
- the premelt already has a C content which is higher than required for the quality to be produced.
- the oxygen blowing converter vessel will tapped steel melt treated as finished melt in a subsequent secondary metallurgical treatment, for example on a ladle furnace or rinsing station.
- a liquefaction or. Reduction treatment of the slag is carried out in the oxygen blowing converter vessel.
- FIG. 1 showing a vertical section through a system according to the invention according to a first embodiment
- FIG. 2 a section along the line II-II of FIG. 1.
- 3, 4 and 5, 6 and 7, 8 and 9, 10 each illustrate alternative embodiments in representations analogous to FIGS. 1 and 2.
- a furnace vessel 1 of a direct current electric arc furnace is provided as an intermediate vessel between a decanter 2 and a converter vessel 3 designed as an oxygen blowing converter, etc. with these vessels 2 and 3 each directly connected so that a coherent reactor system with three functional zones is formed.
- the furnace vessel 1 of the electric arc furnace serves primarily as a melting or melting reduction and heating zone, the converter vessel 3 mainly as a fresh and heating zone, and the decanter 2 as a decanting zone (settling zone).
- a preheating shaft 5 is placed on the lid 4 thereof, which can preferably be fed via a conveyor belt 8 with metallic feedstocks 7 - in particular steel scrap, possibly also solid pig iron and / or sponge iron.
- the conveyor belt 8 is expediently surrounded by a housing 6, so that a heating part 9 is formed in which the feed materials 7 can be preheated during the belt conveying with the aid of burners and / or post-combustion nozzles 10. Heating part 9 and preheating shaft 5 are directly connected to each other.
- the lid 4 of the furnace vessel 1 there is at least one charging opening 11 for the continuous supply of solid, lumpy iron carriers 12 (directly reduced iron, fine scrap, pre-reduced iron ore, sinter, scale, filter dust and / or sludge briquettes, possibly fine scrap, etc.
- the feed takes place via a conveyor belt 15 or conveyor belts.
- the unit of furnace vessel 1, converter vessel 3, decanter 2, preheating shaft 5 and heating part 9 forms the core of a first embodiment of the system according to the invention, which is shown in FIGS. 1, 2.
- the furnace vessel 1 has a single graphite version or, in the case of an alternating current version, preferably a plurality of graphite electrodes 16 for the supply of electrical energy.
- the electrodes 16 can optionally be pivotable within an inclination angle of 0 to 30 ° relative to the vertical in the direction of the center of the furnace vessel 1 and up to 10 ° in the opposite direction to the wall of the furnace vessel 1.
- the angle of inclination can be set or regulated differently for each individual electrode 16 and is usually approximately 15 to 20 ° during melting operation. As a rule, the electrodes 16 are vertical and cannot be pivoted.
- a bottom anode mounted in the center of the bottom 18 of the furnace vessel 1 serves as the counter electrode 17 (with direct current).
- the metallic feedstocks 7 preheated in the preheating shaft 5 by the rising, hot exhaust gases 19 pass continuously into the furnace vessel 1 of the system due to the continuous melting process with continuous power supply.
- Liquid pig iron 20 is continuously fed into the furnace vessel 1 via a pig iron feed device 21 which opens into the furnace vessel 1 and is designed as a channel.
- fine-grained coal 13 • fine-grained coal 13 'or other carbon carriers (processed organic light fraction, e.g. shredder light fraction) and / or
- gaseous oxygen and / or other oxidizing gases 27 (CO ,, H, 0 etc.) and secondary air including air with 0 2 enrichment 28 and / or
- Inert gases 30 (N 2 , Ar)
- Protected and / or unprotected nozzles and / or lances 32 (movable and / or permanently installed lances, optionally as combination lances / burners 32a) at various points in the lid and / or wall area of the electric arc furnace above and / or below the surface of the slag for blowing in at least one of the above-mentioned substances 12 ', 13', 14 ', 27, 28, 29, 30 and / or
- the molten metal 24 formed in the furnace vessel 1 runs into the converter vessel 3 via a weir 34 and is refreshed there until it is tapped and at the same time heated.
- the converter vessel 3 has at least one, preferably several - nozzles, etc.
- protected natural gas protected - but Ar, C0 2 and higher hydrocarbons can also be used as protective gas
- non-protected nozzles such as overbath nozzles for afterburning and / or lances 35 (movable and / or permanently installed lances if necessary as a combination Lances / burners) at various points in the lid and wall area of the converter vessel 3 above and / or below the surface of the slag for blowing up at least one of the substances 12 ', 13', 14 ', 27 to 30 and / or
- a preferred embodiment variant of the converter vessel 3 provides the following:
- the lances 35 are arranged approximately symmetrically on the cover 37 of the converter vessel 3, are movable in the vertical direction and can at the same time be pivoted out within an angle of inclination of approximately 0 to 30 ° to the vertical in or against the flow direction 38 of the molten metal 24.
- control and repair opening 50 is attached approximately above weir 34.
- the fresh slag 25 moves from the converter vessel 3 in the opposite direction to the molten metal 24 in the direction of the arrow 42 to the furnace vessel 1, whereby it acts on the molten metal 24 with ever decreasing temperature or increasing Content of Accompanying elements (C, Si, Mn, P, S etc.) meet and these are heated and freshened or cooled and reduced by this until the slag 25 is tapped through a slag door 22 at the end of the decanter 2.
- the hot exhaust gases 19 formed in the converter vessel 3 first get into the furnace vessel 1 and mix with the resulting exhaust gases before they then rise through the preheating shaft 5 and either (variant without heating part, Fig. 5, 9) the system through the exhaust pipe Leave 46 in the upper area of the preheating shaft 5 or get into the heating part 9 (variant with heating part, FIGS. 1, 2, 7, 8).
- the exhaust gases are partially post-combusted with oxygen 27, optionally with air 28 or air / oxygen mixtures via the lances 32, 35 and / or nozzles 47, nozzles 10 in the heating part.
- Heating part 9 (if provided, preferably with> 30% scrap in the insert mix),
- the starting materials to be used in particular the iron carriers 7 (shape, size, composition, temperature and physical state)
- the main goal in the design is to preheat, charge, melt or reduce melt, refresh, heat and cut-off the process steps within the system at the same time, but at different locations and thus as independently of one another as possible in different parts of the system with a controllable process under favorable physical-chemical processes, to carry out reaction-kinetic and thermal conditions, ie to receive an overall system of almost perfectly (highly effective) working partial reactors for the specific application.
- the configuration of the system according to the invention enables the system area, consisting of oven vessel 1 and decanter 2, to be emptied independently of one another (Via the tap opening 43) and the converter vessel 3, on the other hand, via the tap opening 41 without requiring a tilting of the entire system, which means that control and minor repair work in the hot state of each of these two areas can be carried out at short notice with throttling of the system.
- all parts of the system are preferably locked together during operation as a unit, or cannot be moved or tilted. Due to the preferably section design of both the lower vessel and the lid 4 and 37 of the system, individual or several parts or vessels requiring repair can be replaced after extending laterally (this also applies to the preheating shaft 5).
- the interchangeable container concept is preferred, ie ready-to-use, possibly preheated stand-by containers (e.g. converter container 3 and a unit consisting of furnace container 1 and decanter 2) are available at short notice.
- An overall system configuration with scrap preheating shaft 5 and heating part 9, as shown in FIG. 1, can be used if a certain minimum proportion of solid scrap 7 is used in the mix of operations.
- the following table I can be used as a general guideline for the selection of the overall system configuration depending on the application mix:
- the scrap portion 12 in the furnace vessel 1 and / or in the converter vessel 3 is supplied via the lid openings 11 and 39 with the aid of conveyor belt and slide systems 15, 15 'and 40, the maximum dimension of the scrap pieces 12 must not exceed a certain dimension (e.g. 200 mm).
- the scrap preheating shaft 5 has only a small cross section, since only a little scrap is charged and it is continuously filled by a scrap conveyor belt 8 without a preheating function, ie without a heating part 9.
- oversized scrap pieces may have to be sorted out and cut before use.
- the exhaust gases are removed in the upper, so-called hood area 5 ′ of the scrap preheating shaft 5 via the exhaust line 46.
- At least one scrap preheating shaft 5 is replaced by at least one scrap conveyor belt 8 with a preheating function, i.e. filled continuously by means of a heating part 9.
- a preheating function i.e. filled continuously by means of a heating part 9.
- a scrap preheating shaft 5 with a heating part 9 with a scrap conveyor belt 8 or a plurality of scrap conveyor belts 8 arranged in parallel (FIGS. 1, 2).
- the exhaust gases 19 are removed via a hot gas line (not shown) arranged at the beginning of the heating part 9.
- a preheating shaft 5 with a gas-permeable and water-cooled shut-off device 5 ′′ is placed on the lid 4 of the furnace vessel 1, which preferably uses a conveyor belt with metallic feedstocks 7 - in particular steel scrap, and possibly also pig iron 15.
- the furnace vessel 1 has a plurality of cathodically connected, inclined graphite electrodes 16, which are optionally designed as hollow electrodes, preferably in a symmetrical arrangement with respect to the electric arc furnace and the preheating shaft 5.
- the electrodes 16 are within an inclination angle of 0 to 30 ° relative to the vertical in the direction of the center of the furnace vessel 1 and up to 10 ° in the opposite direction towards the wall of the furnace vessel 1.
- the angle of inclination can be set or regulated differently for each individual electrode 16. It is during melting usually about 15 to 20 °. Occasionally, the pivotability of the Electrodes 16 are dispensed with.
- a bottom anode mounted in the center of the bottom 18 of the furnace vessel 1 serves as the counter electrode 17.
- Temperature e.g. > 800 ° C (scrap preheating temperatures of 1000 ° C and more are quite possible, if necessary using a lined preheating shaft).
- feedstocks can also be preheated, e.g.
- the average decarburization speed depending on the feed mix being from 0.06 to 0.10 (max. 0.12)% C / min, and + with continuous feed of cold feed mix- Components, e.g. Sponge iron and / or iron carbide, possibly fine scrap and / or hot insert mix components, e.g. liquid pig iron (from an upstream blast furnace or a smelting reduction), hot sponge iron and or iron carbide and coal and or fine coal (coke, SLF), lumpy and or dusty slag formers (lime, dolomite, quartzite, fluorspar, etc.).
- cold feed mix- Components e.g. Sponge iron and / or iron carbide, possibly fine scrap and / or hot insert mix components, e.g. liquid pig iron (from an upstream blast furnace or a smelting reduction), hot sponge iron and or iron carbide and coal and or fine coal (coke, SLF), lumpy and or dusty slag formers (lime, dolomit
- the preferred decarburization rate is 0.08 to 0.13 (max. 0.15)% C / min depending on the feed mix.
- the process concept is based on a countercurrent movement of metal 24 and slag 25 in the furnace vessel 1 / converter 3 area, i.e. the slag moves from the converter vessel 3, the part of the plant with the highest temperature and the highest oxygen potential of the metal bath, over the furnace vessel 1 - this has a lower temperature and a lower oxygen potential of the metal bath, because it contains a C-rich molten metal - in the direction of Slag door 22 at the end of the decanting part 2, where the slag 25 can only leave the system.
- the driving force of this movement of the slag 25 is above all gravity, supported by impulses which are transmitted to the slag 25 as a result of the intensive bath mixing in the converter vessel 3 and in the furnace vessel 1.
- the slag 25 encounters metal melt 24 with a low temperature and higher contents of Si and C and is reduced by this, because of the intensive bath mixing, with respect to FeO content and at the same time cooled.
- the subset of the slag 25 from the converter vessel 3 mixes with non-metallic phases formed in the furnace vessel 1 and in the decanting part 2, etc.
- This process feature also means that the residence time of the slag 25 formed in the converter vessel 3 (with very good properties with respect to dephosphorization and desulfurization) in the converter vessel 3 is considerably longer than, for example, in a discontinuous LD converter and can also be regulated, which results in the following advantages : - »better use of the refining properties of the converter vessel 3 supplied
- slag formers supplied in the furnace vessel 1
- the preferred supply of up to 100% of the lime or dolomite in the furnace vessel 1 in fine-grained condition can also significantly reduce the negative impact of the so-called hot spots in AC furnace designs.
- Chunky slag formers are preferably fed into the converter vessel 3 (fine-grained slag formers only when extreme requirements with regard to the raw steel quality have to be met).
- EAF ⁇ LD preferred supply of fine-grained slag formers (especially dust lime, ⁇ dust dolomite) via several nozzles / lances in / through the furnace cover 4, material supply into the hot spot areas
- Exhaust gas from the converter vessel 3 and furnace vessel 1 is drawn off uniformly through the possibly existing scrap preheating shaft 5 and possibly through the heating part 9, the chemical and physical exhaust gas heat being used optimally (divided); if no preheating shaft 5 is provided, the exhaust gases pass from the furnace vessel 1 into the directly connected hot gas line. Almost 100% exhaust gas detection takes place through an encapsulated system with a minimum of uncontrolled emissions or a minimum exposure to heat, dust and toxic exhaust gas components, since no part of the system is opened for charging operations is required. The exhaust gases are increasingly afterburned on the way from the converter vessel 3 to the furnace vessel 1 and further to the preheating shaft 5 and to the heating part 9, depending on the need and the mix of uses.
- Embodiment 1 100% steel scrap
- Embodiment 2 40% steel scrap
- the process and plant variants according to the invention also enable the continuous production of crude steel from 100% sponge iron or from 100% liquid pig iron, in the latter case ore, carbonate, scale, dust briquettes etc. can be used individually or in combination as a coolant.
- Gases oxygen, nitrogen, natural gas, air (compressor and fan)
- Solid coal coal, fine coal (blown coal)
- Refractory materials stones for delivery in the furnace as well as in the converter vessel 3,
- Spray compounds (repair) graphite electrodes for furnace vessel 1 and cooling water: for water-cooled panels of furnace vessel 1, des
- Preheating shaft 5 and the heating part 9 used. Although more cost-effective and / or advantageous in terms of better steel quality, a possible application of alternatives is considered in the next exemplary embodiments
- Fe-containing feedstocks solid pig iron as Fe carriers and / or as coolants: iron carbide, filter dust, scale, dried
- Embodiments 1 and 2 Plant according to FIG. 1 consisting of
- a heating part 9 (conveyor belt 8 with preheating function)
- furnace vessel 1 An AC electric arc furnace as furnace vessel 1, as a melting and pre-freshening vessel
- furnace vessel 1 and the converter vessel 3 have the following identical configuration and equipment, the specification relating to conventional discontinuous systems in accordance with standard series:
- furnace vessel 1 Specification of the furnace vessel 1:
- a lid 4 of the furnace vessel 1 which is made on the outside of water-cooled panels which are provided with a refractory layer from the inside (furnace space),
- Two charging openings 39 preferably only one in operation (only one of them is shown in FIGS. 1 and 3) in the converter cover 37 for continuous feeding of fine scrap (here shredder scrap with a piece size of ⁇ 100 mm) and / or sponge iron pellets (DRI ) 12, lump coal 13 and lumpy slag formers (lime, dolomite, quartzite) 14, which are transported in via a conveyor belt / slide system 40,
- a lid 37 of the converter vessel 3 which is designed in an identical design as the lid 4 of the furnace vessel 1 and forms a unit (section design) with it in the locked state during operation. Approximately above the weir 34, it is provided with a control and repair opening 50. This remains closed during the continuous process.
- the preheating shaft 5 is formed from water-cooled panels which are provided on the inside in the upper hood area with refractory plates (as can be seen in FIG. 1),
- the preheating duct 5 is provided with twelve post-combustion nozzles 47 for oxygen 27, air 28 or an oxygen / air mixture, these post-combustion nozzles 47 being arranged approximately symmetrically on the outer duct perimeter in two levels, each with six nozzles per level,
- Two natural gas / oxygen / air combi burners 10 are arranged in the upper hood area of the preheating shaft 5, which can also be used as afterburning lances and as a burner with max. 3.5 MW can be operated per burner.
- the entire preheating shaft 5 can be made of water-cooled panels with an inner lining, whereby the following advantages can be achieved: - »little heat loss with the cooling water in the preheating shaft or a smaller amount of cooling water is necessary ⁇ higher scrap preheating and flue gas temperatures can be set at the exit of the shaft without risk of malfunction.
- the preheating shaft 5 consists of water-cooled panels which are provided on the inside in the upper hood area with refractory plates,
- the preheating duct 5 is provided with eight post-combustion nozzles 47 for oxygen 27, air 28 or oxygen / air mixtures, these post-combustion nozzles 47 being arranged approximately symmetrically on the outer duct perimeter in two levels, four nozzles per level,
- a natural gas / oxygen / air combi burner 10 is arranged, which can also be used as a post-combustion lance and as a burner for an output of max. 3.5 MW is designed.
- a heating part 9 is provided with two identical scrap conveyor belts 8 arranged parallel to one another within the heating part 9, which are spatially separated from one another within the common housing by a refractory dam (not shown in the drawings).
- the design of the heating part 9 and the scrap conveyor belts 8 can be summarized as follows:
- a vertically aligned refractory dam (wall), which divides the entire interior of the heating part 9 in the longitudinal direction into two sub-spaces that are almost completely separate from one another, each with a scrap conveyor belt 8.
- the insert mix consists of 100% steel scrap (mixed scrap) with the composition according to Table II.
- the system variant according to FIG. 1 with the scrap preheating shaft 5 with an internal useful cross section of serves to carry out the method
- scrap conveyor belts 8 (belt width 2.0 m, belt length 40 m), which are arranged side by side in parallel and before unloading the scrap 7 in the
- Preheating shaft 5 pass through a common, 10 m long heating part 9, the
- Heating part 9 opens directly in the upper hood area of the preheating shaft 5.
- a small portion (11.50%) of the scrap with a piece size of ⁇ 100 mm is fed continuously as a coolant 12 into the converter vessel 3 at a temperature of 25 ° C.
- a scrap piece length of 1.5 m (ie the main part quantity 7 of 88.50%) is charged onto the two scrap conveyor belts 8 with the aid of four scrap loading cranes and, after preheating in the heating part 9 and in the preheating shaft 5, is continuously fed to the furnace vessel 1 and melted there.
- the average height of the scrap column 7 in the preheating shaft 5 is approximately 2.5 m.
- the sensible heat (enthalpy) and chemical heat (heat from the partial afterburning) of the exhaust gases flowing mainly from the furnace vessel 1 into the preheating shaft 5 and into the heating part 9 serve as the heat source for preheating the scrap 7 in the heating part 9 and in the preheating shaft 5 19 as well as the heat from a certain scrap oxidation taking place during the preheating of the scrap.
- the partial afterburning of the exhaust gases 19 in the preheating shaft 5 takes place in two stages, with cold air 28 and gas oxygen 27 being blown in continuously by the twelve post-combustion nozzles 47 arranged in two levels in a volume ratio of approx.
- the afterburning takes place gradually along the heating part 9 by means of continuous Blowing in cold air 28 through a total of ten combination burners / lances 10 (here only as afterburning lances), which are arranged in the lid of the heating part 9 (2 x 5 combination burners / lances 10 above each scrap conveyor belt 8).
- the molten metal 24 in the furnace vessel 1 always has approximately the properties mentioned above.
- the melting and fresh process in the furnace vessel 1 runs continuously and takes place quasi-steadily with very intensive bath mixing with continuous supply of the following substances, media and energies or under the following process conditions:
- Blow coal (fine coal) 13 via the manipulator lances 32 and 23 as well as via the coal under bath nozzles 33 of the furnace vessel 1,
- Converter exhaust gas 19 including dust in the converter exhaust gas, which flow directly from the converter vessel 3 into the furnace vessel 1,
- the products of the furnace vessel 1 are also continuously and semi-continuously removed, including:
- the C-rich, low-Si melt reaches the converter vessel 3 continuously and mixes with the crude steel melt 24 which is always present in the converter vessel 3 during a very intensive bath movement Properties regulated within narrow tolerances:
- the liquid converter slag 25 collects in the converter vessel 3, the surface of which at a slag layer height in the converter vessel 3 of approximately 1.8-2.0 m up to 0.5-1.0 m higher than that in the furnace vessel 1 lies and as a result, driven by gravity and impulses from the bath movement in the converter vessel 3, continuously overflows via the weir 34 into the furnace vessel 1.
- Lump lime 14, quartzite and lump coal 13 also through the charging openings 39 in the converter cover 37,
- the products of the converter vessel 3 are also continuously and semi-continuously removed, including:
- the bet mix consists of
- exemplary embodiment 1 there is a continuous supply of molten pig iron 20 via pig iron channel 21 and sponge iron pellets 12 via charging openings 11 into furnace vessel 1.
- Sponge iron pellets 12 are introduced as coolant into the converter vessel 3, etc. in an amount of approx.8.8% of the mix, i.e. approx. 29.3% of the iron sponge pellets contained in the insert mix, the total proportion of which in the insert mix is 30%.
- the total amount of scrap in the insert mix is charged with scrap loading cranes onto the scrap conveyor belt 8 and, after preheating in the heating part 9 and in the preheating shaft 5, continuously fed or melted into the furnace vessel 1.
- the average height of the scrap column 7 in the preheating shaft 5 is 2.5 m.
- the physical and chemical heat, partial afterburning of the exhaust gases 19 from the furnace vessel 1 and heat from a partial scrap oxidation during the preheating serves as the heat source for preheating the scrap 7 in the heating part 9 and in the preheating shaft 5.
- the partial post-combustion of the exhaust gases 19 in the preheating shaft 5 takes place in two stages, with cold air 28 and gas oxygen 27 being blown in continuously by the eight post-combustion nozzles 47 arranged in two levels in a volume ratio of approx.
- the preheating takes place gradually along the half with the active scrap conveyor belt 8 by continuously blowing in cold air 28 and gas oxygen 27 through the five combi burners / lances 10 in the lid of the heating part 9, which are arranged above the active scrap conveyor belt 8.
- the continuous melting of the scrap 7 preheated in the heating part 9 and in the preheating shaft 5 takes place in the furnace vessel 1 with likewise continuous supply of the liquid pig iron 20 via the pig iron channel 21 and approx. 70.7% of the sponge iron pellets 12 contained in the insert mix via the charging openings 11.
- the resulting molten metal 24 is simultaneously carburized in the furnace vessel 1 to form a low-Si, C-rich melt and partially freshed.
- the metal melt has the following properties before it overflows into the converter vessel 3 via the weir 34:
- furnace vessel 1 including non-metallic components '' portion of furnace vessel 1
- the molten metal 24 in the furnace vessel 1 has approximately the above-mentioned properties during the entire process.
- the melting and fresh process in the furnace vessel 1 takes place continuously and quasi-steadily with very intensive bath mixing with continuous supply of the following substances, media and energies or under the following process conditions:
- Blow coal (fine coal) 13 via a manipulator lance 32 or 33 and via the coal under bath nozzles 33 in the furnace vessel 1,
- Converter exhaust gas 19 including dust in the converter exhaust gas, which flow directly from the converter vessel 3 into the furnace vessel 1,
- the products of the furnace vessel 1 are also continuously and semi-continuously removed, including:
- Exhaust gas phase Exhaust gas f dust) 40.7 vol.% CO 79.7% FeO n 25.5 vol.% CO, 9.4% CaO l, 4 vol.% H, 3.5% SiO,
- the liquid converter slag 25 collects in the converter vessel 3, the surface of which at a slag layer height in the converter vessel 3 of approximately 1.8-2.0 m up to 0.5-1.0 m higher than that in the furnace vessel 1 lies and consequently overflows, driven by gravity and impulses from the bath movement in the converter vessel 3, via the weir 34 into the furnace vessel 1.
- the fresh process takes place in the converter vessel 3 with very intensive bath mixing quasi-steadily with continuous supply of the following substances, media and energies or under the following process conditions:
- Lump lime 14, quartzite and lump coal 13 also through the charging openings 39 of the converter cover 37,
- Exhaust gas gas phase
- Exhaust gas dust 84.8 vol.% CO 93, l% FeOn 9.4 vol.% CO, 3.5% CaO 2.3 vol.% H, 0.7% SiO, 1.1 vol .% H, 0 0.7% C 0.5 vol.% N, 0.3% ZnO l, 3 vol.% O
- the bet mix consists of
- the scrap preheating shaft 5 is replaced with a conventional water-cooled furnace manifold as a connecting piece between the furnace vessel 1 and a hot gas line, not shown in FIG. 3, as is common today for any conventional electric arc furnace,
- the five natural gas / oxygen burners 32a in the furnace vessel 1 are not operated as a burner and are either protected with air to prevent damage until the next need for use or occasionally (but not in the present case) as additional post-combustion nozzles 32a to those in the lid 4 of the furnace vessel 1 existing post-combustion lances 35 are used, and
- the metal melt 24 which arises with the supply of electrical energy in the furnace vessel 1 is simultaneously carburized to a low-Si and C-rich melt (here very limited coal supply) and partially refreshed, so that it follows the weir 34 before overflow into the converter vessel 3
- a low-Si and C-rich melt here very limited coal supply
- the molten metal 24 in the furnace vessel 1 has approximately the above-mentioned properties over the entire process.
- the melting and fresh process in the furnace vessel 1 runs continuously and takes place quasi-steadily with very intensive bath mixing with continuous supply of the following substances, media and energies or under the following process conditions:
- Blow coal (fine coal) 13 via one or more of the manipulator lances 32, 33 and / or the coal sub-bath nozzles 33 of the furnace vessel 1,
- Converter exhaust gas 19 including dust in the converter exhaust gas, which flow directly from the converter vessel 3 into the furnace vessel 1,
- Exhaust gas gas phase
- Exhaust gas dust *
- the C-rich, low-Si melt 24 reaches the converter vessel 3 continuously at an average speed of 4.27 t / min and mixes with the crude steel melt 24 which is always present in the converter vessel 3 during a very intensive bath movement with continuously regulated properties within narrow tolerances:
- the liquid converter slag 25 collects in the converter vessel 3, the surface of which at a slag layer height in the converter vessel 3 of approximately 1.8-2.0 m up to 0.5-1.0 m higher than that in the furnace vessel 1 lies and as a result, driven by gravity and impulses from the bath movement in the converter vessel 3, continuously overflows via the weir 34 into the furnace vessel 1.
- the fresh process takes place in the converter vessel 3 with very intensive bath mixing, quasi-steadily with continuous supply of the following substances, media and energies or under the following process conditions:
- Lump lime 14 and lump coal 13 also through the charging openings 39 of the converter cover 37,
- the products of the converter vessel 3 are also discharged continuously and semi-stationary, including:
- Table V contains a summary of the consumption figures for the production of 1 t of crude steel using the process and plant variants according to the invention.
- the described system concept, etc. in the variant without preheating shaft 5 and without heating part 9 can also be used for the pretreatment of molten metals with or without iron, in special cases operation with negative pressure (e.g. up to 0.1 bar residual pressure in the entire vessel) would also be conceivable.
- This pig iron pretreated in this way is tapped continuously from the converter vessel 3 (e.g. into a downstream intermediate container) or discontinuously into an intermediate container or in pig iron pans) and later used either in a converter or in an electric arc furnace or cast on a casting machine to pig iron pellets. • During the process, both in the furnace vessel 1 and in the converter vessel 3
- Furnace vessel 1 provided only a weak transformer of 20 MVA.
- the electrodes in the furnace vessel 1 can be omitted.
- the above process flow can also be used effectively for the pretreatment of special pig iron with a high content of V, Ti, Mn and P.
- the process and the system are also suitable for the production of molten pig iron with a very low content of accompanying elements (Si, Mn, P and S at the same time), i.e. very suitable for producing a "SORELMETAL" type pig iron from conventional pig iron.
- the process and system application is further explained using an example for the production of a Cr and Ni-rich premelt for the production of stainless steel by subsequent VOD treatment.
- the process flow according to the invention is as follows:
- Chromium, nickel, manganese, molybdenum etc. ores are continuously introduced in a system according to FIGS. 1 and 2 with the conveyor belt 8 via the heating part 9 into the preheating shaft 5 or into the electric arc furnace vessel 1 and preheated.
- liquid feedstocks 20 e.g.
- Pig iron preferably pre-phosphorous pig iron (% P ⁇ 0.025), and / or
- Liquid FeCrHC (from an electric arc furnace or an induction furnace) are fed continuously into the electric arc furnace vessel 1 via the filler trough 21.
- the melting process in the electric arc furnace 1 takes place continuously with intensive bath mixing under the following conditions:
- slag formers 14 such as burnt lime, burnt dolomite, fluorspar etc. - in pieces via the charging openings 11 and / or fine-grained via the nozzles 33 and / or lances 23, 32.
- the aim of the process control in the electric arc furnace 1 is the quasi-stationary setting of certain process parameters, which are as follows when producing a premelt for austenitic steel grade 304:
- Liquid slag 25 always with an approximately constant composition, for example as a directional analysis
- the molten metal 24 with the properties mentioned above runs continuously from the electric arc furnace vessel 1 via the weir 34 into the converter vessel 3 and mixes with the very intense bath movement with the crude steel melt 24 which is always present in the converter vessel 3, which in the present case is a Represents premelt for the next VOD treatment and is always kept in the converter vessel 3 at the composition and temperature desired for tapping about 0.25% C about 1700-1710 ° C.
- the fresh run (mainly decarburization) takes place in converter vessel 3 under the following process conditions:
- slag formers 14 such as burnt lime, burnt dolomite, fluorspar, etc. - preferably in pieces via the charging openings 39, optionally also in fine-grained form via the nozzles 36, Formation of an almost solid slag 25 with an approximately constant composition, for example as a directional analysis approx. 30% CaO 2-5% Al 2 O 3 ⁇ 5% CaF,
- the metal product 24 - a premelt with the properties mentioned above for subsequent VOD treatment - is tapped from the converter vessel 3 via the metal tapping device 41.
- the metal tapping can be carried out continuously or discontinuously without interrupting the process in the electric arc furnace vessel 1.
- the exhaust gases 19 which arise in the converter vessel 3 and in the electric arc furnace vessel 1 are drawn off uniformly via the preheating shaft 5 and the heating part 9 and at the same time are used for preheating the solid starting materials 7.
- the bed in the preheating shaft 5 performs a pre-filter function with regard to dust content in the exhaust gas 19.
- washing-out process is carried out after about 3 hours of operation, for example by feeding somewhat higher amounts of FeSi, lime and fluorspar into the converter vessel 3
- This process enables liquefaction of the slag 25 in the converter vessel 3 and at the same time a reduction in the Cr, O 3 content, so that the slag 25 can easily move in countercurrent movement to the metal 24 via the weir 34 into the adjacent electric arc furnace vessel 1 can occur, without causing high Cr losses, before it then mixes with the slag portion formed in the electric arc furnace 1.
- the so-called washing process is carried out both when the system is operated with continuous and when operated with discontinuous tapping of the metal 24 from the converter vessel 3 without special effort and essential achivi throttling feasible.
- the method according to the invention can also be used for the production of stainless grades with a low C content ( ⁇ 0.05%), ie without a VOD system.
- the deoxidation and desulphurization of the steel takes place in a manner similar to that for carbon steel production during tapping off the converter vessel 3 and the subsequent secondary metallurgical treatment (for example in a ladle furnace or at a rinsing station).
- Significant advantages of the method according to the invention compared to known, discontinuous stainless production methods are:
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Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
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AT110997 | 1997-06-27 | ||
AT0110997A AT404942B (de) | 1997-06-27 | 1997-06-27 | Anlage und verfahren zum herstellen von metallschmelzen |
PCT/AT1998/000160 WO1999000522A1 (de) | 1997-06-27 | 1998-06-26 | Anlage und verfahren zum herstellen von metallschmelzen |
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US (2) | US6264883B1 (ru) |
EP (1) | EP0946761A1 (ru) |
JP (1) | JP2001500243A (ru) |
KR (1) | KR20000068375A (ru) |
CN (1) | CN1082548C (ru) |
AT (1) | AT404942B (ru) |
BR (1) | BR9806107A (ru) |
CA (1) | CA2264665A1 (ru) |
RU (1) | RU2205878C2 (ru) |
WO (1) | WO1999000522A1 (ru) |
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CN117419566B (zh) * | 2023-12-18 | 2024-03-15 | 河北睿阳稀有金属制品有限公司 | 一种海绵铪生产用还原装置 |
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DE1433431B2 (de) * | 1963-10-29 | 1971-12-16 | Fried Krupp GmbH, 4300 Essen | Schmelzofen zur herstellung von stahl und verfahren zum betrieb des ofens |
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US4657878A (en) * | 1985-02-08 | 1987-04-14 | Corhart Refractories | Method of making high density, fusion cast basic metallurgical refractory and the refractory itself |
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-
1997
- 1997-06-27 AT AT0110997A patent/AT404942B/de not_active IP Right Cessation
-
1998
- 1998-06-26 RU RU99105748A patent/RU2205878C2/ru not_active IP Right Cessation
- 1998-06-26 CA CA 2264665 patent/CA2264665A1/en not_active Abandoned
- 1998-06-26 BR BR9806107A patent/BR9806107A/pt not_active Application Discontinuation
- 1998-06-26 CN CN988010852A patent/CN1082548C/zh not_active Expired - Fee Related
- 1998-06-26 JP JP50514699A patent/JP2001500243A/ja active Pending
- 1998-06-26 EP EP98929118A patent/EP0946761A1/de not_active Ceased
- 1998-06-26 ZA ZA985594A patent/ZA985594B/xx unknown
- 1998-06-26 KR KR1019997001616A patent/KR20000068375A/ko not_active Application Discontinuation
- 1998-06-26 WO PCT/AT1998/000160 patent/WO1999000522A1/de not_active Application Discontinuation
-
1999
- 1999-02-26 US US09/258,755 patent/US6264883B1/en not_active Expired - Lifetime
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2001
- 2001-06-29 US US09/893,729 patent/US6508853B2/en not_active Expired - Fee Related
Non-Patent Citations (1)
Title |
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See references of WO9900522A1 * |
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CA2264665A1 (en) | 1999-01-07 |
US20020005083A1 (en) | 2002-01-17 |
AT404942B (de) | 1999-03-25 |
WO1999000522A1 (de) | 1999-01-07 |
KR20000068375A (ko) | 2000-11-25 |
US6264883B1 (en) | 2001-07-24 |
RU2205878C2 (ru) | 2003-06-10 |
BR9806107A (pt) | 1999-08-31 |
US6508853B2 (en) | 2003-01-21 |
JP2001500243A (ja) | 2001-01-09 |
ATA110997A (de) | 1998-08-15 |
ZA985594B (en) | 1999-01-25 |
CN1236398A (zh) | 1999-11-24 |
CN1082548C (zh) | 2002-04-10 |
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