DE2033197A1 - Method and device of metals or metal alloys intended for further processing, in particular steel, or compounds of these metals with other elements, e.g. B. metal oxides, or other fusible earths or substances with the help of the electric arc furnace - Google Patents

Description

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Method and apparatus for further processing of certain metals or metal alloys, particularly steel _{ι> t} or compounds of these metals with other elements, "for example, metal oxides, or other fusible earth or materials with the aid of the electric arc furnace

The invention relates to a method and related methods Equipment and devices for the production of further processing ** processing certain metals or metal alloys, in particular. Steel, as bulk steel or special steel (e.g. semi-finished products) or compounds of these metals with other elements, e.g. metal oxides, or other fusible earths or substances with the help of the electric arc furnace using pourable materials, preferably sponge iron for steel or sponge iron briquettes or other pourable raw materials and additives.

The production of electrical steel has so far been carried out in relatively limited, mostly small batches in known Way by processing scrap in conventional tilting electric arc furnaces in a discontinuous manner -Melting down, freshening, alloying, refining or finishing, pouring - according to the single and multi-slag process depending on Contamination of the input materials with metallurgically undesirable accompanying elements and the desired types and types Quality programs. A major disadvantage of this known method is the low power density per unit, the to relatively low annual usage hours (e.g. approx. 2000 for batch and approx. 3000 for continuous charging) with correspondingly low power plant utilization and thus leads to relatively high investment and operating costs per ton of generation. In addition, occur during the

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Scrap melting due to a very uneven power consumption with frequent breakdown of the arc with direct contact with larger scrap parts on short-circuit or cut-off currents, which have a short-circuit or minimum cut-off capacity in the amount of forty to fifty times the transformer capacity and thus a correspondingly high reserve of the network or the connected power plant to stabilize the power supply network. The wear on electrodes and refractory material is high. There are difficulties in maintaining precise analysis tolerances due to fluctuations in the analysis of the input materials - which results in a reduction in the yield of good blocks or slabs as well as due to the discontinuous operation and the melting and metallurgical work in one work process. When casting, steel and lacquer cannot always be separated cleanly from one another, so that either major losses or certain impurities in the steel cannot be avoided. There are further difficulties in the production of ^{K <} 3correct qualities, and there is only a small possibility of automating the process. The melting of 100% sponge iron in these tiltable arc furnaces is therefore only possible to a limited extent for economic reasons and other difficulties mentioned below. Sponge iron or sponge iron briquettes have, compared to the usual, not _t processed in the metallurgical nature inconsistent Sehrott a low specific weight, a higher specific surface and a lower thermal conductivity and place particularly high demands on their processing "Proposed one has only one naturally necessary continuous charging of these substances, without completely excluding the risk that substantial quantities of the starting materials will stick together in the sense of floating icebergs and cannot be melted down or can only be melted down with great difficulty,

It is the object of the present invention to provide an improved method for producing metals or metal alloys intended for further processing, but in particular steel _f as bulk steel or special steel or compounds

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of these metals with other elements, e.g. metal oxides, or other fusible earths or substances with the help of the electric lightbopen furnace as well as an appropriate device and to create a device with the aim of optimally utilizing the installed electrical power and the stabilization of the power supply network .. Furthermore an optimization of the operational requirements is to be achieved. The creation of a Slag that its processing based on minor components is economical makes it interesting. Through the cooperation of the electric arc furnace with a direct reduction system further operational and economic advantages are to be achieved.

The method according to the invention is characterized _Λ accordingly characterized in that the arc furnace according to the first position of an initial molten bath - Normal operation provided substantially with limited amounts of pourable (in steelmaking hochmetallisierter), largely uniformly held use and aggregates, in particular in tuning of the dosing rate, for heat equivalent or to the energy of the existing molten bath including the slag and the bath and slag movement as well as their even, fine distribution over large areas of the bath and slag. Slag surface, preferably continuously charged and that - preferably also at the time of charging, but after reaction - the slag in the upper area above the melt pool level and the molten metal (steel) or the other molten metal in an area below the slag Substances are withdrawn discontinuously in the required or required partial amount, and at most so far that in the melting chamber of the ingested Iz ge vessel, in order to achieve a longer continuous melting operation, a larger minimum amount of molten material including slag layer for immediate melting of the further, dosed use - and aggregates remain.

109884/0604 ORSGiNAL INSPECTED

The electrodes are adjusted according to the fluctuation of the bath

continual ^ö ,

mirrored automatically / pulled up or added,! ·

The method of the invention is useful in the Way carried out that the the melting chamber of the melting vessel's Total amount of molten material that happens during a maximum continuous operating time, * always subtracted in partial amounts Metal, in particular steel, or other molten material is or can be larger than the unique maximum permissible capacity of this melting chamber

The method according to the invention can be used in such a way that the smelting operation takes place during longer removal breaks interrupted and with reduced electrical energy, the bath is kept in a completely melted state at any time the withdrawal of a portion of the melt and the immediate continuation of the supply of the starting materials and the Melting process allowed while avoiding stronger network perturbations.

According to a further feature of the invention it is provided that the minimum amount of sponge iron or sponge iron briquettes retained in the melting chamber is melted Material approx. 20 to 40% of the maximum permissible capacity of the melting chamber and the slag, the residence time of which can be adjusted until the reaction is complete can, except for a remainder of about 20 to 30% wire).

The method according to the invention can be implemented in an advantageous manner in that the melting chamber of the melting vessel, when creating the initial melt bath, is at least approximately to the extent of the minimum amount from a neighboring furnace of the same operating mode that was previously in operation or a storage container with the properties of Ej, n - substitutes correspondingly melted material including

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a sufficient slag pool, e - if this is operational is considered necessary or advantageous - is charged.

According to a further feature of the invention, the metallurgical work to be carried out in the melting chamber of the electric arc furnace, in particular for the production of bulk steel, can essentially be based on the production of steel iron with such a lower limit in the C content that the slag can be made basic be, or optionally also limited by carburizing on \ gewünschen the unit for producing a raw steel C content to the removal of the phosphorus content. For the production of a standard raw steel as mass steel for direct casting, additional alloying is also possible to a limited extent with the acceptance of a certain amount of burn-off.

Another technical and economic advantage is achieved in that one from the melting chamber with the Partial amount removed at the desired tapping temperature the necessary further metallurgical ones only in special facilities Steps, e.g. desulfurization, degassing, alloying, refining or other process steps to achieve the desired final analysis for the bulk and quality steel is subjected, this work on the production of bulk or Quality steel can also be carried out side by side in parallel. *

For the implementation of the method according to the invention, fixed arc furnaces are particularly suitable, which require a relatively low economic outlay for their creation a preferably permanently installed cover, in particular a fixed vault, which has the necessary openings for the electrodes, lances and the supply pipes for the input and aggregate materials, the dedusting, and that

Possessing liquid feedstocks . i 't

; ORIGINAL SNSPECTeD I

109884/0604 '

According to a further feature of the invention the walls of the tub-shaped furnace far from the electrodes be removed in such a way that damage from radiation is avoided. The distance between the electrodes and the wall is expediently dimensioned so large that feedstocks that are not melted down are deposited on the wall and a Can form a protective layer.

According to the invention to be set in the milk container Basic slag is naturally not very aggressive. But as far as wear and tear or damage to the furnace wall by aggressive Slag cannot be avoided, the invention provides for the wall areas of the exposed to damage Melting space on a wall zone that is as narrowly defined as possible, which is the level of the bath mirror when the molten material is removed Deployment material corresponds to determine which then with the appropriate Lowering the bath level can be repaired with the help of applied gunning mixes «

The method according to the invention not only enables the use of fixed ones that can be produced economically in a favorable manner Arc furnaces for the greatest performance or considerable Throughput rates, e.g. depending on the number of electrodes, over 200 to 300 t per hour; these ovens can also be used with Permanently installed lids, if necessary arranged on raised side walls, to reduce damage caused by radiation be provided. Since the vessel is preferably stationary, the installation of the electrical equipment is essential Simplified, the allocation of the input and aggregate materials and for the implementation of others is also possible Measures required equipment and devices simplified

The method according to the invention creates good conditions for a special and advantageous mode of operation, according to which a melting plant at least two to three

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fixed production units (melting rooms) can have, which among each other under assumption of a minimum quantity of already melted from the same raw materials Material can be approached »

All or some of the production units can be can be used to store the molten steel or the like.

If there are several production units, a considerable Achieve economic advantage in that this Units is assigned a convertible electrical device that is kept lower in number by one or two operating units each, an interchangeable vessel without electrical installation is assigned.

The method according to the invention including training dune and arrangement of the arc furnaces is particularly suitable for the application of the following features, namely the charging is now to be carried out through such a number of supply pipes through the lid of the melting vessel that a uniform fine distribution of the feedstock and aggregates between the electrodes and the wall of the Melting space as well as between the electrodes themselves regardless of the number of these electrodes in approximately precise coordination the dosing rate to the energy of the bath and the slag with simultaneous control of the bath and slag movement by one or more of the following measures

a) Adjustment of the residual oxygen content of the sponge iron or the like by choosing a certain degree of reduction in direct reduction,

b) Supply of carbon through lances or other suitable measures, i

■ r ·.

c) supply of liquid oxygen, if necessary,

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take place, so that a particularly good heat transfer between the continuously charged input and aggregate materials and the slag or the bath is guaranteed, so that in the ideal case each charged single grain through the passage the eye varnish or at the latest when you hit the bathroom immediately is melted down and slagged, the melting temperature »which is relatively low due to these measures can be kept, is kept constant above the liquidus temperature. These measures also ensure that agglomerate formation is avoided «

The aforementioned measures for treating the melt in conjunction with the charging with the starting materials lead to a significant improvement in the operation of those electric arc furnaces that do not have all the features of the method according to the invention can be applied.

In those cases where, when starting up an electric arc furnace for the initial creation of an initial molten bath, none Minimum amount of molten bath from another electric arc furnace or storage furnace or pig iron or other liquid input materials are available, in order to avoid excessive load on the power supply network, the scrap or other solid feedstocks existing first charge with reduced electrical power melted down · The longer melting time is compared to the advantages achieved in the process steps described above which then follow and the considerable simplification of the entire system is now insignificant.

When charging to a liquid sump, with low voltage and current and the switch-on peak caused by the low inrush current through a suitable attenuator, e.g. a capacitor »so compensates "that repercussions on the network are avoided"

109884/0604

During the beginning of the charging process, the amperage and -Tension * increased gradually until a uniform maximum . Power consumption is achieved by the procedure according to of the invention as a result of constant current and voltage ratio ' se remains constant during the melting process and avoids network perturbations, which at the same time ensures constant high power power consumption of the transformer and a steady base load operation of the power plant with high utilization is achieved «

The method according to the invention provides an essential one A prerequisite for the weld pool now being reduced or interrupted in the supply of sponge iron can be exposed to controlled overheating in such a way that that in the subsequent stages in the respective withdrawal vessel or other devices an additional alloy »preferably during the degassing, can generally be carried out without additional heat supply. If necessary, however, a Such heat supply also take place via arcs or inductively generated eddy currents. Each melting pot are depending on Throughput, the desired variety and quality program and the requirements of the further processing stages » in particular the pouring device, one or more steel * assigned collecting container, in which, if necessary, the standard raw steel transported directly to the pouring devices or parallel to this in further metallurgical steps such as reduction, oxidation, alloying, refining, to the desired one Final analysis is brought. For this purpose, ζ »Β» would be movable Arc or inductively heated ladle furnaces with suction deoc.il or combined heated vacuum vessels can be used.

The method of the invention provides another essential prerequisite for that, in conjunction with the selection of raw materials, possibly the pelleting of Ore or other raw material mixtures in precisely specified Ratios and concentrations and direct reduction with Attitude'd @ s reduction: 3gx »ad - 3S iJas j @ Htilig @ liaö © lieslS

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can be charged with raw materials that remain uniform can, in addition to iron, manganese, chromium, titanium and vanadium oxide or other oxides that are in this melting pot accumulate in the slag, where they accumulate to an extent that can be determined by the aforementioned hatreds that they can be obtained economically by further processing the slag,

The method according to the invention for generating electricity " steel or a material to be produced in the same way also creates a good basis for composite work the continuous arc melting process with a upstream direct reduction system, the facilities for steam and electricity generation through immediate exhaust gas utilization, in particular Equipment for oxygen and melt flow generation, has

A melting vessel of the electric arc furnace which is particularly suitable for carrying out the method according to the invention is that this vessel for the withdrawal of the portions of the molten steel is a deep closable opening, in particular bottom opening, and in the upper area of the wall with offset or height. staggered lockable drainage channels are provided for different amounts of slag. The closure of the Bottom opening can be mechanical, e.g. by means of a plug, or take place with magnetic material by induction currents This is also the case with FluidxRStahl with the appropriate training Drainage channel can be sucked off and conveyed away.

All basic features as well as those for Supplementation and improvement of the former, further features of the invention, some of which are only treated later, lead to Achievement of considerable technical and economic! Advantages, which are summarized and summarized below waitestKahend

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First, a continuous charging of pourable raw materials and additives is achieved with even, fine distribution on a liquid melt pool between the * electrodes, but also between the electrodes and the wall, with precise adjustment of the dosing rate to the energy of the arc or the melt pool * The Art charging enables particularly good heat transfer between the raw materials and additives, as well as slag and bath, and enables them to be melted down quickly with controlled and controlled bath movement. In this way, agglomerate formation is avoided. The melting temperature is at ... ',,. Normal operation constant above the liquidus temperature and can be increased in a controlled manner if the dosing rate is reduced. This * leads to constant power consumption during the meltdown and thus to a reduction in the required network reserves as a result of reducing or avoiding network perturbations while at the same time operating the power plant at a constant base load with high utilization. This is associated with a reduction in the electrical power to be installed due to the higher average power consumption of the transformer. An improvement in the electrical and thermal efficiency is achieved by the; Operation of the transformers with a relatively low active power factor. The transition to short, current-intensive arcs with a corresponding reduction in radiation is still possible, as is the transition to UHP technology. Because the layer of slag is always present, heat losses due to radiation are very low. The arcs do not require any regulation, which also limits or prevents inductive losses. A high number of hours of use is achieved when melting down as a result of separating between melting including refining and dephosphorization in three-shift continuous operation and the further metallurgical process steps. The method allows the use of preferably stationary melting vessels, as well as the application

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of interchangeable vessels with the possibility of implementing the electrical equipment and, if applicable, the mechanism for the lances required to feed certain elements and other facilities in a relatively short time. All metallurgical work can be done before the process begiryi can be set. Automation of the process can be achieved * Charging does not require any in normal operation Interruption. At the same time can be discontinuous Deduction of steel or dpi. in the desired quality in a deep-set area. In the same way, after the reaction has been completed, the slag can be extracted from a suitable upper area of the vessel can be withdrawn discontinuously * The steel is free of slag components; Fe losses are reduced to the lowest possible level.

Through the continuous addition of slag formers, predominantly lime and carbon; during the melting process, the carbon content and slag composition become constant held. The reaction time of the slag and the thickness of the slag layer are adjustable. That way you can too Input materials with high slag proportions processed without a reduction in performance and the reaction times until they are achieved to a qualitative or operational optimum.

The separation between melting and the further metallurgical stages xxx in just one process combination enables the production of a unitary steel as required Consistent composition, which is poured directly into the melting vessel when the analysis is adjusted accordingly can be. If higher quality mass steel or quality steel is required, the one removed from the arc furnace can be used Subset in the downstream metallurgical stages can be brought to the desired final analysis. This can be done if necessary be carried out in parallel with mass steel production «If the downstream metallurgical work in mass steel relates to the Degassing is limited and the formation of carbon fouled υπ

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any additional alloying takes place during the melting process, would also be * a combination of the melting vessel with a subsequent one continuous degassing possible.

In the case of the stationary melting vessels which are preferably used, the particularly permanently installed ones are used Lids or vaults enable economical construction »

The batchwise discontinuous withdrawal of standard raw steel on the one hand and slag on the other hand, leaving a residual melt of about 20 to 30% allows one over long-term permanent condition. This is suitable Melting vessel for storing crude steel, since it can now be dimensioned sufficiently large, in the melting vessel sponge iron and sponge iron briquettes or other raw materials with different proportions of slag can be melted, because now over the »over a certain height range provided in the upper area, extended or distributed Slag discharge channels the thickness of the slag layer can be determined without any disadvantage for the melting process. By Adjustment of the thickness of the layer of residual slag after deduction and the introduction of steel and slag when relining it is achieved that the arcs burning on the liquid bath are always covered. It can also be kept so large that the distance between the electrodes and the wall a non-melted residue of the input materials is deposited on the wall to achieve a protective effect * The Distance between the bath level and the lid of the melting vessel can be kept large.

A major advantage of the process is that each melting pot with a residual melt or with unitary raw steel from another melting vessel or a storage vessel can be approached, and if necessary protected by a also introduced Schlaekanso

• ORIGINAL INSPECTED

1038.847.0894

the furnace wall, usually only in the slag area can occur while the furnace is in operation when the bathroom level is lowered, by applying suitable spraying compounds be performed*

The adjustment of the metallurgical work and the dosing rates before the start of the process and the automation of the process lead to an improvement in the yield of good ingots or slabs · The various measures continue to be used for Improvement of the operational and collective bargaining situation.

When carrying out the method according to the invention, the lowest possible Fe losses occur when the slag is drawn off, because the slag thickness and also the slag discharge can be adjusted depending on the reaction of the slag and the course of the reaction via the movement of the bath and the slag in the specified manner is controlled, in particular by setting the residual oxygen content in the iron ** "isim or _t in the sponge iron briquettes"

The preparation of the input materials with regard to the uniform composition of the slag by selecting suitable ones Ores or in connection with the mixer ore pelleting before use in the direct reduction plant creates an economy Lich interesting possibility for further processing dier Slag on by-products · The slag falls in a largely uniform composition as a result of the set thickness as well as the control of the reaction time and the conversions.

The decrease in the exhaust gas occurring in the direct reduction quantities for steam and electricity generation, especially for oxygen and melt flow generationj leads in connection with the Other measures mentioned to utilize the installed electrical power and stabilize the network. It

S8 84 / 08b ^! 4 "■ ORKÜNAL iwrccTB»

is thus the establishment of continuously working Smelting works are possible that are largely independent of external electricity needs.

Come as feedstock for the production of steel primarily sponge iron or other pourable, highly metallized iron supports such as sponge iron briquettes * The use of recycled small pieces of scrap is being considered, which will be used increasingly in the future the market is likely to come. It is scrap, for example from motor vehicles that have been withdrawn from the market, which are in machined in a special system, whereupon the non-magnetic

ingredients see parts being removed. With the mentioned new in / is with a largely controllable analysis to be observed within narrow limits, with which the metallurgical work to be carried out ^{before the start of smelting λ would be known and adjustable.} This enables the use of a process control for material transport, metering and addition as well as melt management, which in turn represent the prerequisite for optimizing metallurgical work, melting process and melting temperature and the overall process over time / The ores available for direct reduction are generally phosphorus- and low-sulfur «Here, the metallurgical work with mass-produced steel is essentially limited to setting the required carbon content. If necessary, you can dephosphorize by adding lime during the first stage of melting. All other metallurgical steps - desulphurisation, degassing, alloying and, if necessary, further carburizing as well as other metallurgical steps - take place in additional devices as in the production of quality steel.

The refining can preferably take place during melting are carried out by removing the residue contained in the input materials.

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substance reacts with the continuously introduced carbon. The carbon addition is determined according to the previously determined The residual oxygen content of the highly metallized starting materials is measured so that the required final carbon content of the crude steel can be set precisely. Excess carbon carburizes the steel.

To a largely continuous operation with the highest possible To achieve annual usage hours, the melting, freshening and any necessary Dephosphorization of the melted sponge iron from the additional metallurgical work that may become necessary. Melting down is therefore carried out in the preferably stationary melting vessels, their size and melting capacity according to the operational ones Requirements of the further processing stages are interpreted. Since these fixed ovens are compared to conventional tiltable vessels can be created extremely economically and also the use of more than three electrodes each Oven is possible, the capacity of these ovens increases initially only limited by operational requirements. However, it is beneficial when securing production at least two to three production units (melting vessels) are provided. If a melting pot fails can then continue working. Each melting unit also supplies the minimum amount of melted down when required Steel including slag for restarting a melting pot. The power density and thus the Hourly output of such melting vessels is considerably higher than that of conventional tilting electric arc furnaces, because as a result of the separation between melting and the further

essential metallurgical work is melting down / only in the event of malfunctions or the transition to a change, vessel can be interrupted got to.

The economical construction of fixed furnaces allows them to be dimensioned in such a way that they can be used for steel storage to the extent required by the company. In the event of malfunctions in the further processing stages _t, for example in a strand casting plant, the contents of the pans made available for pouring can now be returned to the melting vessel or a steel reservoir. If it is necessary to completely empty a meltdown vessel due to shutdown, the remaining molten bath can also be fed to an adjacent meltdown vessel or a steel store in this case.

The economical design of the melting pot makes it is also possible with particularly simplified interchangeable vessels to work *. If possible, at least two, preferably fixed, melting vessels with only one electrical device used by itself or with a movable cover including cover and possibly with a lance device in a very short time from one can be transferred to the other interchangeable vessel. The operational optimum would be two melting vessels in operation with a centrally arranged interchangeable vessel on stand by. The way of working with interchangeable vessels contributes to significant measure to increase the electrical usage hours at.

For loading the single-use containers with the pourable highly metallized or other input materials is still, to point out the following: Charging takes place by using the sponge iron or other free-flowing materials such as lime, carbon and if necessary also alloy elements, brought into high-lying bunkers by a conveyor belt and then from there with the help of a suitable one Dosing and transport device are continuously fed to the melting vessel via downpipes. This procedure

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enables, especially for the future, continuous hot charging of the raw materials, i.e. the sponge iron is produced directly from the direct reduction plant fed to one melting vessel in the hot state within the set dosing rate.

When placing the sponge iron or other input materials between the electrodes or the electrodes and the wall, the fine, even distribution of the materials on the bath surface is important. If the dosing rate, the bath temperature and the bath movement are set correctly, the additives are melted immediately. Agglomerate formation is avoided. With the help of the adjustable in sponge iron rest Auer toffgehaltes and / or the other Naßnahmen mentioned - supply of carbon or supplying liquid \ oxygen - can always be worked with boiling bath or boiling slag. This makes it possible to melt even 100% sponge iron without difficulty and to ensure that all fresh, decarburization and slagging reactions run smoothly.

A major advantage of continuous charging pourable and highly metallized feedstocks compared to batch-wise one-remaking lies in the shortening of the Fresh and fine-tuned times as well as the elimination of dead times for carrying out intermediate analyzes and re-charging. This melting vessel can be used evenly during the melting process with the specified melting rate and thus with even laistunps intake without the scrap business usual significant backlash. operate·

The aforementioned method of operation leads to batchwise compared to Charging to the desired essential stabilization of the power supply network, achieved through the most extensive constant power consumption with a reduction in the required Metz reserve and a reduction in the installed

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Performance due to higher average power consumption of the transformer and avoidance of the usual in scrap business Short-circuit or cut-off currents that suddenly load the network to a considerable extent / start-up with reduced Voltage and current intensity xxxxx Compensation of the relatively low inrush current caused inrush peak. The high annual number of hours of use that the procedure according to the invention can still be considerably more than 7000, not only leads to optimal utilization the installed electrical capacity, but also to an improvement in the use of power plants. In addition to lowering the Investment and processing costs by increasing the Power density per unit will also enable electricity tariffs to be reduced.

The usability of the melting vessels for steel storage enables the use of various operational measures, such as interrupting the meltdown, if necessary Throttling of the power, the melting in only one vessel, Patch with lowered bath level or transition to the interchangeable vessel, so that at peak times of the network load the Power consumption can be reduced. The possibility of steel power supply can help bridge these peak times.

The above-mentioned mode of operation can by the already known measures to improve the electrical and thermal Efficiency can be supplemented, such as

Operation of the transformers with relatively low Active power factor,

Transition to short current-intensive arcs with '' corresponding reduction in radiation,

Transition to UHP technology (Ultra High Power).

_f 'ORIGINAL INSPECTED

109 6 64 twwxk

In the manner already mentioned, if necessary, by supplying oxygen with the help of one or more oxygen lances the melting capacity increased and the bath and slag movement improved. The oxygen supply, i.e. the one required for it The lance can also be used to feed fine-grain lime. By combining the oxygen supply with increased carburization of the bath by introducing suitable carburizing agents, a Achieve shortening of the meltdown time while saving electrical energy at the same time.

A steel iron or standard raw steel is used in the melting vessels Manufactured with a constant composition, which is based on post-treatment in further process steps the desired final analysis is brought. In this way, with a combination of processes, the optional production of a Steel iron or unified raw steel of uniform quality, the composition of which is varied as required can, as well as the production of any quality steel is possible. The automation of the process and any Setting the batch sizes for bulk and quality steel ensures compliance with precise analysis tolerances for the finished steel and optimal adaptation to the further processing stages by specifying and strictly adhering to the tapping weights possible.

While in the conventional working methods with tiltable electric arc furnaces to the acceleration desired there emptying pans are generally used with a large capacity, the potting in a continuous casting Iage At least in the case of the billet programs, operational difficulties due to the limitation of the casting cross-sections and the casting time and therefore often require reheating on special heating stalls, this can be done according to

Steel iron or the invention produced / unit raw steel from the fixed

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Melting vessel without affecting the melting time in such portions or pan contents are taken as required to achieve an operational optimum for the Continuous casting or intermediate processing in further metallurgical stages appears necessary.

in large pans This is how large portions / are removed from slabs and when

Use quality steels, smaller pans or receptacles.

j ■. "j '· j- ^ t, · metallurgical work

det, in which the further / takes place in the manner already mentioned In the method according to the invention, parallel work is possible, i.e. mass steel can be produced in a continuous casting plant at the same time and od with the help of the smaller pans. Like. Quality steel are usually produced in small quantities.

To start up an electric arc furnace, in the way already mentioned several times a unit raw steel can be used as residual melt ι the in the vessel by a Slag layer is protected.

Another possibility for starting is the Use of standard raw steel including the corresponding amount of slag from another melting vessel available, liquid pig iron or processed scrap can also be used for running in, the latter being the case is melted down with reduced power. The scored Uniformity of the melting process leads to a significantly lower level of noise pollution compared to the usual use of scrap in conventional light ovens. .

From the stationary melting vessel used according to the invention, the steel is withdrawn discontinuously from the lower section of the vessel into a removal vessel, the bath level naturally fluctuating in the rhythm of the tapping. The crude steel is usually zoned off during the charging process. After filling the sampling aggregate is

ORlGIlSiALiMSPECTtD

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the tapping opening is closed again mechanically or inductively with the aid of a suitable device, e.g. a stopper. Depending on the program and the one made during melting For metallurgical work, the standard raw steel can be cast directly in a continuous casting plant or in casting stands or first brought to the desired final analysis in further metallurgical steps. With reduced The sponge iron supply in the melting vessel is at all times Possibility of controlled and controlled overheating «of the bath. This generally allows an alloy in the further stages, preferably during the degassing, without further supply of heat, with a supply of heat through if necessary Arcing or inductive is possible.

Working with fixed melting vessels and Interchangeable vessels leads to conventional high-performance arc furnaces to a reduction in investment costs per ton of crude steel. Through the context of the procedure and stopping the metallurgical work before the start of the process, the operating costs are also reduced. In particular, the personnel costs, the maintenance and repair costs and the expense for refractories Material and electrodes reduced. .

The slag that has formed in the melting pot is withdrawn discontinuously from special lockable slag discharge channels in the manner mentioned in each case. The drainage channels can be attached to the vessel, preferably opposite the steel tapping channel, at several levels. In this way, sponge iron with different levels of constituents can be processed on slag carriers The method or the device according to the application does not interfere with the growth of the slag layer, because it does so when necessary can be deducted up to a required residual amount of about 20 to 30%. The slag layer can thus

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vary both in their thickness and in their dwell time » i.e. set * Before slag is withdrawn, you can wait until the slag has completely reacted. Iron losses are therefore very small. The removed steel is in any case free of slag, i.e. pure.

The slag withdrawn in the aforementioned manner falls always in a predetermined uniform composition, so that they are particularly suitable for processing Suitable by-products. There is a major advantage in the case when working in conjunction with direct reduction. The direct reduction enables in particular the Processing of iron, nickel, cobalt and oxidic copper ores on a direct route to metal, which is with it accumulate in molten steel or metal when melted · 'On the other hand, manganese, chromium, titanium and vanadium oxides become as well as other oxides are not reduced and remain in the slag when they are melted down, from which they are in the corresponding Holdings of the original ore can be obtained by leaching or other suitable methods. By choosing suitable Ores and their preparation for the process, if necessary in connection with mixer ore pelleting the ores before use in the direct reduction plant, it is possible to use the feedstock with such a proportion of secondary components to produce that their extraction from the slag is possible under economic conditions. In addition, the content of secondary components in standard raw steel, such as nickel, can be predetermined.

There is also the possibility of collaborative work with an upstream direct reduction system including Steam and electricity generation for exhaust gas utilization, in particular for oxygen and melt flow generation. The at the Direct reduction of large amounts of exhaust gas, especially when using gas-rich coal as a reducing agent, can

109884 / 06-04

are preferably used to generate steam and electricity »In the conventional way of working, the electric arc furnace however, the measures necessary to stabilize the network generally prevent such use, especially corresponding networks are very often not available and feed into the public network during the melting pauses, if available, is not always possible. The aforementioned continuity of the melting with constant However, power consumption without significant network perturbations allows such use, provided that it is directly connected the direct reduction system is used. if the The available exhaust gas quantities are large enough, in this way there is the possibility of setting up continuously working smelting works, largely independent of external electricity purchases »

According to the invention, the method can, if required, also be used for the continuous melting and remelting of non-ferrous metals and non-ferrous metal alloys or other pourable non-ferrous metal scrap materials or compounds of metals with other elements or other fusible earths or materials with the aid of the electric arc furnace will. The application is given in particular for those metallurgical processes where the arc can be used as an energy source in the melting furnace or remelting furnace ^ the feed, additives and alloy materials in pourable, i.e. preferably in granulated, pelletized, briquetted or other small-piece form or in a liquid state are present or can be converted into such a state - and can therefore be charged continuously and a separation between continuous melting with portion-wise removal of sump contents and slag and the further metallurgical process steps can be used, e.g. reduction of zinc oxide in zinc production, production of copper Nickel alloy

109884/0604

V ²⁵ -

gene (Monel metal) with subsequent production, production; of commercial and anode copper, with a series connection if necessary to save process steps depending on requirements between continuous melting and after interruption of the meltdown of reduction, oxidation, alloying, finishing or other necessary metallurgical work is possible in the same vessel »

In the method according to the invention can with advantage Hot charging can be used. In this way you can achieve further savings in electrical energy *

In the accompanying drawings is an apparatus largely schematically illustrates how it can be used for carrying out the method according to the invention.

Fig. 1 shows in the sense of a floor plan a unit for continuous electrical steel production on the basis of "sponge iron"} _v

Fig. 2 shows the same unit in the sense of a vertical section to Fig. 1..

In the embodiment according to the drawing, the melting shop has three fixed production units, namely melting vessels 1, 2 and 3. These are stationary, in particular trough-shaped vessels which have a lid or a vault 4 and are provided in the lower area with a closable opening or channel 5 for drawing off or sucking off the melted metal, in particular steel. In the upper region of the vessel wall 6, in particular on the side opposite the aforementioned removal opening 5, several slag tapping channels 7 are provided, which are offset in height from one another so that slag ^! can be withdrawn at different altitudes. These openings or channels can be closed. At least the two outer melting furnaces are each assigned an electrical part with the electrodes 8. The middle melting vessel 2 is provided as an interchangeable vessel or storage vessel which, for example, after one of the two outer furnaces 1 or 3 is shut down, with the then released '

ORiGlNAL INSPECTED

109884/0604

electrical equipment to be equipped. the electrical equipment can thus be exchanged between the melting vessels.

This melting plant shown in the drawing is assigned or connected downstream at a suitable distance Continuous casting plants 9 or others for the production of Hassenstahl and quality steel suitable facilities, one or more steel receptacles 10 are also provided depending on Program in which the one taken from a melted-in Partial amount to a special level / with optional supply of electrical energy to increase the heat content further metallurgical steps, e.g. desulphurisation, degassing and alloying to produce appropriate steel qualities will. The degassing hoods that can be placed on the pans are located in the area of this ladle stand 11 and facilities 12 for the provision and addition of any additives and alloying materials required, as well as any required facilities for the supply xx * electrical Energy,

First, for example, in the one melting vessel 1 creates an initial molten bath while avoiding overloading the network, then the charging with as much as possible uniformly kept input materials in the production of steel, in particular sponge iron and sponge iron briquettes, initiated and continued continuously. The specific steps of the procedure are in the introduction set out in this description. The electrical device has several vertically, continuously lowerable and retractable ones Electrodes, which are held at a greater distance from the container walls, so that when required feed material can deposit to protect the walls. Via the feed pipes 13 and the metering and transport device IU, the loading

1 0988 A / 0604

Sending the melting room, for example, with the one Bunker 15 causes raw materials and aggregates removed in a precise, finely dosed Menre on the surface of the melt pool. Forms on the melted crude steel or the like a layer of slag 16, during the charging of the One-dimelzgefäßes with input materials tu-like. can the thickness the slag layer can be changed to the desired level »whereby via one of the openings 7 slag enters the slag container 17 is deducted, from where it may be a Further processing can be fed to the by-products contained in it. Just like the slag, the crude steel can od. Like. 18 each in the required or required Partial amount can be withdrawn via the channel 5, the ladle 10 either directly to the continuous casting plant 9 or initially

10 '

the mentioned stand * / to carry out the further metallurgical Work can be carried out until the desired final analysis is achieved. That way either in parallel or one after the other The mass or quality steel produced can then optionally be transferred to the continuous casting plant or the other facilities, e.g. for casting chill molds.

To start up the second melting vessel, a partial amount of crude steel including slag is removed from the vessel 1 so that the melting operation can be started immediately with the continuous supply of raw materials. In the event that one of the furnaces 1 and 3 is shut down, the melting furnace 2 provided as a wax vessel is filled in the aforementioned manner with a minimum amount of crude steel and, if this is desired to avoid radiation, also with a corresponding amount of slag Device 8 is lifted from the furnace, which has been put out of operation, and placed on the interchangeable vessel, so that here, too, the melting process is initiated and operated quickly and without overloading the network.

10 9 8 8 47 0 6-0 A

If a fault occurs at the ladle furnace or at the slab "casting plant to _t can provided for casting or further processing in the container 10 Schmelzbadmenge be poured back into one of the melting furnaces are in operation, for which purpose the filling equipment are naturally equipped with filling apertures * It is also the possibility of keeping one of the melting vessels ready for storing a quantity of crude steel including a layer of slag or at least temporarily using it for this purpose in order to be able to continue steel production with the stored crude steel in times when a greater network load is not desired or not possible .

109884/0604

Claims (1)

P a t e η t an sprue h e: 1 · Process for the production of metals or metal alloys intended for further processing »especially steel» as bulk steel or special steel (e.g. semi-finished products) or compounds of these metals with other elements, e.g. metal oxides or other fusible earths or substances with the help of the electric arc furnace of pourable feedstocks, in the case of steel preferably sponge iron or sponge iron briquettes or other pourable feedstocks and aggregates, thereby geke η η ζ calibrated η et that the arc furnace after the first creation of an initial, molten bath - assuming normal operation - essentially with limited quantities of pourable (with the Steel production, highly metallized) raw materials and additives kept as uniform as possible, especially when coordinating the dosing rate, the heat equivalent or the energy of the existing melt pool including the slag and the bath and slag movement as well as their uniform f a distribution over large areas of the bath or slag surface, preferably continuously charged and that - preferably also at the time of charging, but after reaction - the slag in the upper area above the molten bath level and the melted area in an area below the slag Metal (steel) or the other molten materials are withdrawn discontinuously in the required or required partial amount, at most so far that a larger minimum amount of molten material including slag layer for immediate melting of the other » dosed feedstock and aggregate remains * ORIGINAL INSPECTED 109884/0604: 2. Method according to claim 1 _9, characterized in that the electrodes of the electric arc furnace are automatically and continuously raised or adjusted in accordance with the fluctuation of the bath level. 3, method according to claim!., Characterized in, that the one passing through the melting chamber of the melting vessel during a maximum continuous operating time, total amount of molten material always subtracted in partial amounts Metal, in particular steel, or other molten material is or can be greater than the unique maximum permissible capacity of this melting chamber, 4, method according to claim 1 or 3, characterized that the melting operation is interrupted in the event of major breaks in removal and with reduced electrical Energy the bath is kept in the fully melted state, which at any time draws off a subset of the melt as well the immediate continuation of the feed of the input materials and the melting process while avoiding stronger network recoil » kings allowed * 5, method according to claim 1 or one of the following, characterized in that the im Melting space retained minimum amount of material melted in particular from sponge iron or sponge iron briquettes about 20 to 40% of the maximum permissible capacity of the Melting space and the slag, their residence time up to can be set for complete reaction until a remainder of about 20 to 30% is withdrawn, 6, Method according to claim 1 or one of the following, characterized in that the melting chamber of the Einschmelztefäßes least about dev minimum quantity of the same from a previously been in service neighboring furnace during the making of the initial molten bath within the scope of operating 108884/0604 type or a storage container with the quality the input materials corresponding to the molten material including a sufficient amount of slag - if this is considered operationally necessary or advantageous will. 7. The method according to claim 1 or one of the following, characterized in that the im Metallurgical furnace to be carried out in the melting area of the light furnace Work, especially for the production of bulk steel, essentially on the production of a steel iron, with a such a lower limit in C-Rehalt that the slag is basic can be adjusted, or by carburizing on the for Production of a standard raw steel with the desired C content, if necessary, is also limited to the removal of the phosphorus content ». 8. The method according to claim 1 or one of the following, thereby R e k e η η ζ e i c h net that one from The partial quantity removed from the melting chamber at the required tapping temperature is only provided in special equipment further metallurgical steps, e.g. desulfurization, degassing, alloying, refining or other process steps, to achieve the desired final analysis for the mass and Quality steel is subjected. 9. The method according to claims 7 and 8, d a d u r c h ge denotes that the work to produce of bulk or quality steel can be «run parallel to each other * 10. The method according to claim 1 or * one of the following, characterized gekennzei ch.net that the melting of the sponge iron od. Like. In preferably solid. standing, in particular tub-shaped, electric arc furnaces (1, 2 or 3) is carried out. 109884/0604 11. Device for performing the method according to Claim 10, characterized in that that the electric arc furnace has a preferably permanently installed cover, in particular a fixed vault » the openings for the electrodes and lances as well as for supply pipes for the feedstock and aggregates and for the filling of liquid feedstock possesses. 12. Device for performing the method according to claim 10, characterized in that that the preferably trough-shaped electric arc furnace (1) has more than three electrodes. 13. The apparatus of claim 12, d a d u r c h characterized in that the walls (6) in the wan-. in the shape of a furnace (1) are far away from the electrodes » such that damage from radiation is avoided is. 14. The apparatus according to claim 13, characterized in that the distance between the electrodes and the wall is so large that there are feedstocks that are not melted down, can deposit on the wall and form a protective layer. 15. The method according to claim 10, characterized in that the by aggressive slag the wall area of the melting chamber exposed to the damage to a wall zone that is as narrowly defined as possible, that of the bath level movement when the molten feed material is removed corresponds to »is fixed» which can then be repaired with the aid of applied gunning mixes when the bath level is lowered accordingly. 16. Device for performing the method according to Claim 10, characterized) that the fixed production units (melting vessels) with permanently installed »if required on raised side walls 109884/0604 arranged lids to reduce damage caused by Radiation are provided, 17. The method according to claim 10, characterized in that - k e η η ze ic h η e t that a melting plant at least two to three fixed production units (melting rooms) has, which are melted with each other while assuming a minimum amount of already constantly the same starting materials Material can be approached 18. The method according to claim 17, d a d u r c h g e k e η η ζ eic η e t that all or some of the production units (1, 2, 3) for storing the molten steel or the like. Can be used. , 19. Device for performing the method according to Claim 10, in particular claim 16, d a d u r c h e k e η η ζ e i c h net that the production units a feasible one that is kept smaller in terms of number electrical device is assigned by each one or two operating units, one interchangeable vessel without electrical Installation is assigned. 20. Process for melting 'sitähl, etc., in electric arc furnaces in particular according to claim 1 or one of the following, characterized in that the charging by such a number of feed tubes through the lid of the melting vessel is made that a uniform fine distribution of the feedstock and additives between the Electrodes and the wall of the melting chamber as well as between the electrodes themselves regardless of the number of these electrodes in an approximately precise adjustment of the dosing rate to the energy of the bath and the slag with simultaneous control of the Bath and slag movement through one or more of the following measures a) Adjustment of the residual oxygen content of the sponge iron or the like by choosing a specific! degree of direct reduction,. .109884 / 0604 ORIGINAL INSPHCTED- b) Supply of carbon through lances or others suitable measures, c) supply of liquid oxygen, if necessary, takes place in such a way that a particularly good heat transfer between the continuously charged input and aggregate materials and the slag or the bath is guaranteed, so that in the ideal case each charged single grain through the passage the slag, or at the latest when it hits the bath, is melted and slagged in immediately, the melting temperature being relatively low due to these measures can be kept, is kept constant above the liquidus temperature. 21. The method according to claim 1 or one of the following, characterized in that upon commissioning an electric arc furnace for the initial creation of an initial molten bath while avoiding excessive loading the Stromversorgunesnetzes an initial charge consisting of scrap or other solid materials with reduced electrical power is melted down. 22. The method according to claim 1 or one of the following, characterized in that rejects that in batches approached to a liquid sump with low voltage and amperage and caused by the low inrush current the inrush peak caused is compensated by a suitable attenuator, e.g. a capacitor, that repercussions on the network are avoided 23. The method according to claim 22, characterized in that the current strength and voltage are increased in stages during the beginning of charging until a uniform maximum power consumption is achieved, which remains constant during the melting process .109884 / 0604 original inspected 24. The method according to claim 1 or one of the following, characterized in that with reduction or interruption of the supply of sponge iron exposes the weld pool to controlled overheating is, such that in the subsequent stages in the respective Withdrawal vessel or other devices, an additional alloying, preferably during the degassing, can generally be carried out without further supply of heat, 25. The method according to claim 24 »dad u r eh ge ke η η ζ ei c h η e t that if necessary a heat supply via arcs or inductively generated eddy currents takes place. 26. Device for performing the method according to Claim 24 or 25, d ad ure h, that each melting vessel, depending on the throughput, the desired variety and quality program and the requirements of the further processing stages, in particular the Vergießeinrichtunp, assigned to one or more steel receptacles are, in which, if necessary, the unitary raw steel is transported directly to the pouring devices or in parallel with them is brought to the desired final analysis in further metallurgical steps. 27. The device according to claim 26, characterized by the use of movable arc or Induction heated ladle ovens with suction lids or combined heated vacuum vessels. 28. The method according to claim 1 or one of the following, characterized in that in conjunction with the selection of the raw materials, optionally the pelletizing of ore or other raw material mixtures in precisely specified ratios and concentrations and the direct reduction with setting the degree of reduction, the respective melting vessel with uniform remaining feedstock is charged which, in addition to iron, contain manganese, chromium, titanium and vanadium oxide or other oxides that are found in these 988 4/060 * 4 'originally inspected Melting vessel will accumulate in the slag, where it will turn into a through the aforementioned measures can be enriched to a determinable extent so that they are economical by further processing the slag are recoverable. 29. Process for the production of electrical steel or a material to be produced in the same way »characterized by the composite work of the continuous according to AnsDruch 1 borrowed arc melting process / with an upstream Direct reduction system, the facilities for steam and electricity generation through immediate exhaust gas utilization, in particular Equipment for oxygen and melt flow generation, on «- shows. 30. Device for carrying out the method according to, Claim 1 or one of the following, characterized that the melting pot of the electric arc furnace a deep, closable opening, in particular, for withdrawing the partial quantities of the molten steel BodenöffunR, and in the upper area of the Wall with staggered or staggered lockable drainage channels for different amounts of slag is provided. 31. The apparatus of claim 30, d a du rc h indicates that a mechanical closure, e.g. formed by a plug, for the bottom opening is provided. 32. Apparatus according to claim 30, characterized in that that in the case of magnetic goods, a closure caused by induction currents is used in the bottom opening finds. 33 * Apparatus according to claim 30 or one of the subsequent claims, characterized) in that the f- Bpdenöf 9884/060 4 or _IGI nal (nspectesj -. 37 - tion to a device for sucking off liquid steel od. Like. Is connected. 34. The method according to claim 29, d a d u roh ge k e η η « draws that the melting pot when composite work with a direct reduction plant with extracted from the latter hot sponge iron is charged in the predetermined amount. 35. The method according to claim 1 or one of the following, characterized in that the arc furnaces a hot charge is used in such a way that a further saving of electrical energy occurs. 36. The method according to claim 1 or 7, d a d u r c h geke η η ζ eich η et that by continuously adding slag formers, predominantly lime and carbon, the carbon content and the slag composition are kept constant during the melting process. 37. The method according to claim 36, d a d u r c h g e - k e η η ζ e i c h η et that the reaction time of the slag and the thickness of the slag layer are adjustable such that that feedstocks with high slag fractions without. Degradation processing the response time is extended until a qualitative or operational optimum is achieved can be. 38. The method according to claim 1 or one of the following, characterized in that in cases where the downstream metallurgical work in the case of bulk steel is limited to degassing and the formation of the carbon content and possible additional alloys take place during the melting, a combination of the melting vessel with a subsequent continuous continuous degassing is used 109884/0604 39. The method according to claim 1 or one of the following, characterized by the setting of the metallurgical work and the dosing rates before the start of the process and automation of the process. 40. The method according to claim 39, characterized by the use of a process control for material transport, Dosing and addition as well as melt management. 41. The method according to claim 1 or one of the following, characterized .by a reduction the power consumption at peak times of the network load when continuing the work following the meltdown the steel storage unit. 42. The method according to claim 20, characterized that the lance provided for the oxygen supply at the same time for the supply of fine-grained Lime is used. 43. The method according to claim 1 or one of the following, characterized in that in connection with the automation of the process and the arbitrary setting of the batch sizes for bulk and quality steel precise analysis tolerances for the finished steel and an optimal adaptation to the further processing stages by specification and precise compliance with the tapping weights is made possible. 44. The method according to claim 1 or 2 and one of the following, characterized in that the steel iron produced or the unitary raw steel is removed from the fixed melting vessel without impairing the melting time in such portions or pan contents as is necessary to achieve an operational optimum for * Continuous casting or intermediate processing in further metallurgical stages is necessary. 109884 / 06CU 45. The method according to claim 1 or one of the following, characterized by its application for the continuous melting and remelting of non-ferrous metals and non-ferrous metal alloys or other pourable non-ferrous metal scrap materials or compounds of the metals with other elements or other fusible earths or substances of the electric arc furnace. 109884/0604