WO2011009579A1

WO2011009579A1 - Sealing and filling device for a metallurgical furnace, metallurgical furnace, and method for tapping the metallurgical furnace.

Info

Publication number: WO2011009579A1
Application number: PCT/EP2010/004392
Authority: WO
Inventors: Gerhard Fuchs
Original assignee: Fuchs Technology Holding Ag
Priority date: 2009-07-20
Filing date: 2010-07-19
Publication date: 2011-01-27

Abstract

Device for temporarily sealing a tap hole (12) which has a first internal diameter (d3) and is provided in the bottom (10, 11) of a metallurgical furnace (100), and for filling the tap hole (12) with a free-flowing fire-resistant compound VM, having a sealing and filling pipe (31) with a first length I₁ and a bottom opening (31u) and a top opening (31o), a first container (32) for filling compound VM, an opening and closing device (33), and a lifting mechanism (40), in which device the sealing and filling pipe (31), the first container (32) and the opening and closing device (33) are fixed to the lifting mechanism (14) in such a way that the first container (32), with the interposition of the opening and closing device (33), is connected to the top opening (31o) of the sealing and filling pipe (31) such that the connection can be opened and closed by the opening and closing device under the control of a control device, the sealing and filling pipe (31) has on its underside an external diameter d2 which is greater than the first internal diameter, and the lifting mechanism is designed to permit the sealing and filling pipe (31) to be moved in the longitudinal direction of the same at a speed > 200 mm/s.

Description

Sealing and filling device for a metallurgical furnace, metallurgical furnace and method for cutting off a metallurgical furnace

The invention relates to a sealing and filling device for a metallurgical furnace, a metallurgical furnace and a method for cutting off a metallurgical furnace. Metallurgical furnaces, such as e.g. electric arc furnaces have long been known in the art. For example, reference is made to EP 0 184 140 B2, the first figure of which is shown in FIG. 8. Such an electric arc furnace 100 has a furnace vessel 1 with a lid 2. Electrodes 3, which are held by electrodes tear-shark 4 and retractable by opening in the lid 2 in the furnace vessel and extendable are supplied to form an arc with power. By means of the arc, feedstock such as scrap is melted to form a bath of liquid steel FS. The furnace vessel has a bottom 10 with a refractory lining 11 in which the bath is made of liquid steel FS on. On the underside of the furnace vessel 1 a not shown in Fig. 8 tap hole is provided, via which the liquid steel FS removed from the furnace vessel (- tapped) is.

Usually, not the entire mass of the liquid steel FS is tapped, but a residual amount (sump) remains, usually in the range of at most 50%. rather 20 to 40% of the total mass before tapping off.

To cut off the oven vessel is usually tilted over a cradle. The tapping opening is mounted in the bottom of the furnace vessel in such a way that, after the furnace is tilted back into the starting position, the remaining sump is no longer above the tapping opening, so that it can be closed with a refractory filling compound before the next melting process.

During the tapping process, in which the furnace vessel is tilted, usually the electrodes must be pulled through the lid 2 from the furnace vessel. The entire process of parting, which takes 5 minutes or more, depending on the size of the furnace vessel, is one of the so-called non-productive times when operating a metallurgical furnace. In such non-productive times, the furnace can not be operated to melt feedstock. In order to overcome this disadvantage and to enable the parting of such a metallurgical furnace without tilting operation and thus to reduce the idle time during parting off, sealing and filling devices for tapping openings of metallurgical vessels have been considered in the prior art, as described in EP 0 356 618 A1 (US Pat. US Pat. No. 4,966,314) and EP 0 859 678 B1 (corresponding to US Pat. No. 5,914,087). In EP 0 356 618 A1, two refractory parts are pressed against each other for sealing each with circular cylindrical sealing surfaces. In EP 0 859 678 B1, a compressible, refractory sealing material is attached to the lower end of a sealing and filling pipe, which during passage through the melt, which has temperatures between 1500 and 1700 ° C., is protected against the effects of the melt by an additional medium is, which largely prevents the contact of the refractory sealing material with the melt. The residence time of the compressible refractory material in the molten bath is given as 15 to 30 s. EP 0 974 801 A1 (corresponding to US Pat. No. 4,520,861) discloses a further sealing and filling device in which the lower opening of a fill tube is kept closed during the passage of the molten bath. DE 34 37 810 A1 (corresponding to US Pat. No. 4,736,930) discloses a sealing and filling device in which a tube with a refractory lining is kept free of melt and cooled during passage through the melt bath by blowing an inert gas. From EP 1 172 162 Al a device for closing and sealing a tap hole of an electric arc furnace is known, in which a free-flowing filler mass between two linear slide, which close the taphole from below, is filled.

DE 103 55 549 A1 (corresponding to US Pat. No. 7,497,985 B2) discloses a charging material preheater for a metallurgical furnace, which enables a quasi-continuous charging of charge material.

It would be advantageous to have an improved tapping system with integrated sealing and filling functions for metallurgical furnaces, in particular for electric arc furnaces, which enables a further reduction of the so-called non-productive times.

Therefore, it is an object of the invention to improve the absolute slag-free parting of a metallurgical furnace without tilting movement. This object is achieved by a sealing and filling apparatus according to claim 1, a method according to claim 12 and a metallurgical furnace according to claim 15.

Further developments of the invention are specified in the dependent claims.

The invention makes it possible to achieve the completion of the tapping and filling of the tapping opening in a period of <10 s.

The invention makes it possible to prevent protective measures for the sealing and filling pipe, since the refractory metal layer is at least on the underside and inside, preferably also the outside, up to the height to which the pipe is immersed in molten bath and slag, having. Cold melt and / or steel buildup on the pipe typically breaks down between the tapping operations after cooling, particularly at the critical inside of the pipe, or does not build up over normally uncritical wall thickness greater than 30 mm, usually not more than 10 mm, up.

In particular, in combination with the completion of the tapping and filling the tapping opening in a period of <10 s, a substantially maintenance-free sealing and filling device is provided.

In combination with a quasi-continuous charging in an electric arc furnace even a parting without significant interruption of the melting process is made possible.

As a rule, in an electric arc furnace with quasi-continuous charging, a sump of about 40% of the total mass of the liquid steel is left in the furnace before parting off. The height of this remaining steel bath above the tap hole is usually in the range of about 300 mm. Above the steel bath is still a layer of about 200 to 300 mm slag. With a travel speed of at least 200 mm / s, the sump can thus be passed through in a time <2 s. Liquid steel has a viscosity similar to water, so that it flows through narrow cross-sections with flow rates in the range of 2 m / s. Even with a height of the tap opening of 1 m is so after the sealing in and over The tapping hole remaining liquid steel drained after 1 s at the latest. Thereafter, the slide for closing the tap opening can be completely closed. During this closing process, the free-flowing refractory material can already fall through the sealing and filling pipe, since it takes for the passage of the path up to the slide dependent on the drop height and flowability period in the range of 1 to 3 s.

This means that completion of the sealing and filling process can be achieved within a maximum of 6 s. For such short residence times in the melt, if necessary, a sealing material provided on the underside of the sealing and filling pipe does not have to be refractory, but on the contrary, even conventional O-rings or the like can be used.

All complicated arrangements and arrangements from the state of the art can be dispensed with, since a rapid passage through the sump is ensured either by appropriate design of the lifting and slewing gear or by a corresponding mass and thus weight of the sealing and filling pipe.

Further features and expediencies will become apparent from the description of exemplary embodiments with reference to the figures.

From the figures show:

1 shows in a) a cross-sectional view of a section of a metallurgical furnace with a taphole according to one embodiment, in b) the opening of a) with a sealing and filling system according to an embodiment of the invention, in c) the elements from b) in FIG a sealing position, and in d) the cutout X from c) in an enlarged view;

2 shows in a) a metallurgical furnace with a sealing and filling system according to the embodiment in a first position, in b) with the sealing and filling system in a second position, in c) with the sealing and filling system in one third position, and in d) again in the second position;

Fig. 3 is an enlarged view of Fig. 2a); Fig. 4 is an enlarged view of Fig. 2b);

Fig. 5 is an enlarged view of Fig. 2c);

Fig. 6 is an enlarged view of Fig. 2d);

7 shows in a) the view from FIG. 2 a), and in b) the sealing and filling system in a fourth position;

8 is a cross-sectional view of an electric arc furnace according to the prior art

Technology; and

9 is a timing chart of a tapping operation according to an embodiment. Hereinafter, an embodiment of a metallurgical furnace according to an embodiment of the invention using the example of an electric arc furnace with a sealing and filling device according to an embodiment of the invention will be described. Fig. 1 shows a portion of a furnace vessel 1, in which a tapping opening 12 is provided in a bottom 10 with refractory lining 1 1. The tapping opening 12 is through an opening and closing device 13 with a slider 14 is obvious and closable. In the state shown in Fig. 1, the tap hole is filled with a free-flowing refractory material VM, so that the slider 14 is not in direct contact with the liquid metal FS of the molten bath. Above the molten bath there is a slag layer S. The molten bath of liquid steel FS stands with a height h ₆ above the tapping opening 12. In FIG. 1 a) a state is shown in which 60% of the liquid steel FS, corresponding to a height hi, should be tapped. The remaining sump, which is formed by 40% of the molten steel FS, has a height h ₂ correspondingly (h ₆ = h | + h ₂ ). The inner walls and the bottom of the furnace vessel 1 are covered with refractory material 1 1. Perpendicular to the tapping opening 12 is in the furnace vessel, an opening 16 which is closed by a cover, not shown, provided.

By moving the slider 14, the underside of the tapping opening 12 can be opened, so that first the free-flowing refractory FM falls down from the opening 12, and then the liquid steel FS can flow through the opening. This is well known in the art.

In order to ensure an absolutely slag-free parting off, a residual height h ₂ of approximately 200 to 400 mm, normally approximately 300 mm, of liquid steel above the tapping opening 12 must be ensured remain in order to prevent suction of slag S, which is with a height h ₃ of about 200 to 300 mm above the liquid steel FS safely into the outflow vortex.

When parting off by tilting the furnace vessel, the furnace vessel is tilted back into the starting position when this residual height h _{2 has been} reached so that no liquid steel FS and slag S more are present above the tapping opening after tipping back and the tapping opening is free from above is accessible.

In a parting without tilting the furnace vessel is not possible.

Therefore, the embodiment of the absolutely slag-free parting off a sealing and filling device 30 with a sealing and filling pipe 31 and a container 32 for free-flowing refractory material VM. The sealing and filling tube 31 has a lower opening 3 Iu and an upper opening 3 Io, which are located at opposite ends in the direction of the longitudinal axis 311 of the tube 31. The container 32 is connected with the interposition of an opening and closing device 33 with the upper opening 3 Io. As can be clearly seen in FIG. 1 b), the container 32 is arranged above the upper opening 30 of the tube 31 such that when the opening and closing device 33 is opened, the free-flowing refractory material VM falls through the tube 31 under the action of gravity can.

The sealing and filling device 30 or the arrangement of tube 31, container 32 and opening and closing device 33 is movable in the vertical direction back and forth. As a result, the sealing and filling device 30 can be moved in the direction of the tapping opening 12 through the opening 16 in the vertical direction. This can be seen very clearly in FIG. 1 b) from the dotted representation of the lower end of the tube 31, which is identified by 31 ', and in FIG. 1 c). The sealing and filling pipe 31 has a length Ii which is greater than the height h ₂ . The height h ₂ is usually at most half the total height h _{6 of} the liquid steel FS before tapping, so that the length Ii is at least greater than half of this filling height h ₆ . Preferably, the length I ₁ is dimensioned so that the opening and closing device 33 and the container 32 can remain outside the furnace vessel 1 when the tapping opening 12 is sealed, as shown in Fig. Ic). This means that the length 1) is preferably greater than the height of the furnace vessel above the tapping opening 12. At the bottom of the sealing and Verullrohrs 31 a sealant 34 is attached. This sealant preferably has a height I ₃ , which is greater than or equal to 20 mm, so that unevenness in the surface of the refractory material 1 1 can be compensated for the tap hole 12. Preferably, the height I ₃ in the range 40 to 50 mm, so that unevenness in the surface of the refractory lining 1 1 in the range 20 to 30 mm, which occur regularly, can be compensated.

The volume of the container 32 is dimensioned such that it is greater than the volume of the tapping opening 12, which is calculated from the cross section of the tapping opening 12 and its height I ₂ .

In Fig. Id), the circled portion X of Fig. Ic) is shown enlarged. In the left half in Fig. Id), the state immediately after the filling and the beginning of the upward movement of the sealing and Verullrohrs 31 is shown. In the lower end position of the sealing and filling tube, the sealing compound 34 is deformed for sealing, as can be clearly seen in the right-hand part of FIG.

Fig. 2 shows in a) to d) in perspective view the states shown in Fig. Ia), b), c) are shown. In this case, FIG. 1a) corresponds to the illustration in FIG. 2a), FIG. 2b) and d) correspond to FIG. 1b), and FIG. 2c) corresponds to FIG. 1c).

As can be clearly seen in FIGS. 2 a) to d) and the corresponding enlargements in FIGS. 3 to 6, the sealing and filling device has a lifting and rotating mechanism 40, on which the sealing and filling tube 31, the container 32 and the opening and closing device 33 are attached as a sealing and filling arrangement. The lifting and slewing gear has a vertical arm (lifting tube) 41 and attached to the upper end of the vertical arm 41 cross member (cross arm) 42. The cross member 42 is attached at a horizontal end to the vertical arm 41 and holds at its other horizontal end the assembly of tube 31, container 32 and device 33. A lifting and pivoting device 43, preferably a hydraulic lifting cylinder with displacement measurement and a roller slewing ring not shown, is formed so that the arm 41 is vertically movable up and down and is rotatable about its longitudinal axis. As is evident from FIGS. 2 a) to d), the arrangement of tube 31, container 32 and device can thereby be achieved 33 both in the vertical direction moves up and down as well as be pivoted in the horizontal direction. The position of the longitudinal axis of the vertical arm 41 and the length of the horizontal arm 42 are dimensioned so that attached to the one horizontal end of the horizontal arm 42 assembly of tube 31, container 32 and device 33 via the opening 16, the furnace vessel 1 is pivoted and is movable up and down in these. That is, the distance of the tube 31 in the horizontal direction from the longitudinal axis of the arm 41 corresponds to the distance of the opening 16 from the longitudinal axis of the arm 41. The lifting and slewing gear is preferably attached to the oven cradle or connected thereto. According to a first embodiment, the lifting and slewing gear is provided with a double-acting hydraulic cylinder for the lifting movement, which is an adjusting movement in the longitudinal direction of the tube 31, ie normally in the vertical direction, at a speed of> 200 mm / s, preferably> 300 mm / s, and more preferably> 400 mm / s. The sealing and filling system 30 has a control device, not shown, which is connected to the lifting and rotating device 43 and the opening and closing device 33. The lifting cylinder has a measuring device for measuring the travel, and transmits the corresponding measurement data to the control device. The control device is connected to drive the hydraulic cylinder with these. The control device is adapted to calculate from the measured travel the position of the lower end of the tube 31 above the upper edge of the tapping opening 12, so that the last part of the travel of the sealing and Verfüllrohres 31 for sealing the tapping opening 12 at reduced speed can be. To reduce the speed, the control device controls the hydraulic cylinder or its control valve, etc. so that the adjustment speed is reduced and the adjustment in a position in which the sealant 34 is sufficiently compressed, is terminated. That is, the lower end of the tube 31 is stopped at a height <I ₃ above the tap opening 12.

In an alternative embodiment, the hydraulic cylinder is formed only for rapid process in the vertical direction against gravity. However, the hydraulic cylinder can allow a free fall of the arrangement of vertical arm 41, horizontal arm 42 and pipe 31, container 32 and closing device 33 under the action of gravity. In this embodiment, the mass of this arrangement, if necessary. By attaching additional weights, adjusted so that the desired speed of more than 200 mm / s or more (see above). Again, the hydraulic cylinder has a displacement measurement so that the last remainder of the travel, as in the first embodiment, can be controlled by driving the hydraulic cylinder at a reduced speed to the lower end position.

The optionally provided sealing material 34 may be formed of refractory sealing material, but preferably inexpensive O-rings or the like of non-refractory materials such as e.g. Rubber, perfluoroelastomer, polyethylene or polytetrafluoroethylene used.

The sealing and filling pipe 31 is preferably a refractory clad pipe. The opening and closing device 33 preferably has a slide that is hydraulically, pneumatically, electrically or piezoelectrically displaceable for opening and closing the connection between the tube 31 and the container 32.

The container 32 is preferably open at the top, so that it is easily refillable by means of a device 44 shown in Fig. 7b). For this purpose, the container by pivoting the arm 42 in a fourth position, which is shown in Fig. 7b) are pivoted. There free-flowing refractory material VM can be filled from a reservoir 45 via a chute 46 in an appropriate to the volume of the tap opening amount under the control of the control device.

A method for absolutely slag-free parting of a metallurgical furnace such as an arc furnace without tilting the furnace vessel will be described below with reference to FIGS. 1, 2 and 9.

After the container 32 has been filled in the fourth position shown in FIG. 7b) and, if necessary, the sealing material has been replaced, it is moved as shown in FIG. 7 a) or FIG. 2 a) or FIG. 3. There it remains during the melting process of the feedstock.

When the feed is melted, ie the oven is in the condition shown in Fig. 1 (a), the spool 14 is moved away below tapping opening 12 so that the free-flowing feed VM falls downwardly out of the opening 12 and the liquid steel FS the tapping opening 12 can leak. The steel is received in a known manner in a metallurgical vessel or the like. The tapping operation begins in Fig. 9 at time t _a and runs during a period T _A in the range of 2 to 5 min., Depending on the size of the oven. At the time t ₀ in FIG. 9, the tapping process is ended, ie the minimum height h2, which still guarantees an absolutely slag-free parting, has been reached. At this time, the sealing and filling pipe 31 with the associated assembly 30, 40 has been moved to the position (second position) shown in Fig. 2b) and Fig. Ib). Now, the filling pipe can optionally be shut down to the position indicated by 31 'in FIG. 1b) so that the travel path is reduced. However, this is not essential since the shutdown can also be started from the position shown in FIG. 1b) with corresponding control times. The decisive factor is that the path through the remaining liquid steel FS with the height h2 is very fast. For the sake of simplicity, it is assumed in FIG. 9 that to represents the point in time at which the lower end of the tube 31 enters the slag layer S. At this point, a distance of approx. 500 to 600 mm must be covered before sealing. At an actuating speed of 200 mm / s to 400 mm / s, this is overcome in 1.3 to 3 s, eg at 300 mm / s with a maximum of 2 s. Shortly before the lower end of the travel, at time t _r , the control device controls the hydraulic cylinder so that the lowering speed is reduced. The reason is that the tube is so heavy that a completely abrupt deceleration on the one hand is not possible and on the other hand would involve the risk of very hard on the refractory lining 1 1 strike and damage these and / or the pipe.

At time t _1}, ie after about 1.3 to 3 s, the tap opening 12 is completely sealed off. Now only the remaining in the tapping hole 12 and the pipe 31 liquid steel FS must flow, which at a height I _{2 of} the tapping opening of 1 m maximum 2 s, normally 1 s, needed for drainage. The time interval between ti and t ₂ is thus 2 s or less at a height I ₂ of 1 m. At time t ₂ , the slider is moved to the closed position and the closing of the tap opening 12 by the slider is completed at time t ₃ . This process takes considerably less than 1 s. At the time t _v , the opening and closing device 33 opens the passage of the container 32 into the tube 31, so that the free-flowing refractory material can fall through the tube into the tapping opening 12. This happens under the effect of gravity with a likewise high speed in the range of 2 m / s. For this purpose, the tube has an inner diameter which at least the Inner diameter of the tapping opening 12 corresponds. The inner diameter of the tapping opening 12 is in the range of 200 - 300 mm, depending on the wear.

In a first embodiment, the slider of the device 33 is actuated when the slider 14 is closed, ie t ₃ = t _v . Since, however, the free-flowing refractory material also takes a certain time until it has arrived at the slide 14, this time t _{v can} also lie before the time t ₃ , as indicated by dashed lines in FIG. 9 with t ' _v . How much the timing can be advanced is easily determined from the rate of fall and the length Ii of the tube 31. At the time t ₄ , the filling of the taphole 12 is completed with the free-flowing refractory material VM, so that at the time t $, which may also coincide with the time U that pipe 31 can be moved up again.

At this time, then, the state shown in Fig. Id) on the left side.

The correct lower end position of the tube 31, which changes over time due to wear of the refractory lining 11, is determined by calibration, e.g. by measuring the hydraulic parameters or similar, set in operation by the control device.

As is clear from the above description of the method, the total time from the first contact with the liquid metal until completion of the filling of the taphole 12, that is, the time in which the sealing material 34 should retain its sealing ability, easily to less than 10 s and without Difficulties are also brought under 6 s.

In combination with a quasi-continuous charging of the electric arc furnace, as described in DE 103 55 549 Al, therefore, the non-productive times in the operation of such an electric arc furnace can be virtually completely eliminated.

This is possible with the described solution in the simplest possible way, since the adjustment of the system to a very fast sealing and filling no special measures such as sealing surfaces made of refractory material, gas flushing, protection of Dichtmateria- materials by other materials or the like are necessary.

With the solution described, it is also possible to determine the useful life of the perforated brick, ie the exchangeable refractory lining of the invention shown in FIG. 1, in particular in FIG. Stichöffnung and the tap hole 12 to extend 300 to 400%. Usually, the tap hole of a 100-ton furnace has a diameter of 180 mm at the start of use and the tap hole of a 160-ton furnace has a diameter of 210 mm. In the course of use, the diameter of the hole becomes larger due to abrasion. In this case, a diameter increase to 200 to 210 mm and in a 160 t oven diameter increase to 230 to 240 mm, ie from 10 to 15%, is usually considered tolerable in a 100 t oven. The reason is that with the larger hole diameter, the risk of slag clogging increases significantly, and in particular, the amount of slag that is tapped will increase significantly if the furnace is not tipped back in time.

Since with the solution described a timely interruption of tapping is possible, i. Within seconds, when slag is actually tapped, larger diameter changes of up to 30 or 40% can be tolerated. For example, as in the illustrated embodiment, if the inner diameter of the seal and fill tube 31 is equal to 240mm, then for a 100 ton furnace with an initial taphole diameter of 180mm diameter changes up to about 240mm can be tolerated. For a 160 t oven, a 260 to 270 mm diameter tube could be used.

The replacement of a hole stone takes about 3 hours, so a corresponding stoppage of the furnace. The brick must usually be replaced within a few days. Since the wear with a larger hole diameter becomes smaller, the solution described here can be used to extend the interval for replacing the perforated stone to 1 week or so. During the usual filling of the tap hole with the free-flowing refractory material, this is poured from above in the direction of the tap hole through the opening 16. In this case, 130 to 150% of the amount corresponding to the volume of the tap hole used. With the described solution, this amount can be limited. Theoretically, no excess amount at all, ie 0% excess amount, is necessary. In practical use, one can limit the excess to 5 to 10% of the volume, ie a total of 105 to 1 10%. The commonly used free-flowing refractory materials such as Perfllll or Olifill are relatively expensive. By using the sealing and filling tube 31, a cheaper material can be used in the lower third of the hole, and thus the costs can be further reduced.

The optionally provided sealing material 34 can be omitted, in particular, if no large unevennesses exist in the region around the taphole 12. Even with small leaks between the bottom of the sealing and Verfüllrohres 31 and the refractory lining 1 1 of the furnace is through the very fast Befϊillen the tap hole 12 with the free-flowing refractory material 32, the passing through these leaks amount of steel so small that it does not matter. That is, due to the high speed of sealing and filling, or the short time of e.g. <6s are dispensed with the sealing material with a corresponding flatness of the refractory lining 11. The tolerable irregularities are in the range <10 mm, preferably <5 mm.

As previously described, the sealing and filling tube 31 is preferably a refractory clad tube. It is particularly preferable to provide the pipe with a metal coating. Preferably, the coating of a hard chrome coating is used which has a thickness in the range 50 microns to 1000 microns, preferably 100 to 1000 microns, more preferably 150 to 300 microns. such as 200 microns thickness is formed. The hard chrome layer is usually applied by electroplating, the layer thickness preferably being applied in several passes (2, 3, 4, 5,...), Preferably in 3 passes, so that it is as free of cracks and as flat as possible. There are also other metals and metal alloys with correspondingly high melting points such as titanium, tantalum, etc. possible, but chromium is preferred. Essential for the coating is a higher melting point than the temperature of the steel bath, ie at least 1750 ° C, but preferably more than 1800 ⁰ C and more preferably more than 1900 ⁰ C (chromium has a melting point of 1908 ° C). The material preferably exhibits low wettability, as is the case with chromium. Of course, it is also possible to make the tube with greater thicknesses of the coating or entirely of the corresponding refractory metal material, but this is not preferred for cost reasons. In principle, it would be sufficient to coat the sealing and filling pipe 31 on its underside and the inside up to the height h ₅ , to which the sealing and filling pipe is immersed in the molten bath and the slag, and on its underside. The underside and the inside, respectively, are critical in terms of buildup, as greater build-up on the underside would interfere with sealing and greater layer thicknesses of build-up on the inside reduce the tube diameter.

To improve the durability of the tube and since it is anyway more practicable for the formation of the coating, it is preferred to provide the inside and the outside at least up to the minimum height h _$ and the bottom with the metallic material with a high melting point. Of course, it is easily possible to coat the pipe further than the minimum height h ₅ , eg 50, 100, 150,... Mm higher than the minimum height h ₅ , which, as already explained, usually in the range of 200 to 700 mm lies. Tests with a corresponding pipe with hard chrome coating have shown that deposits of slag and / or steel flake off after cooling of the sealing and Verfüllrohrs after a tapping operation, or by slight mechanical shocks, such as a striking the pipe or knocking with a hammer are removable. As far as adhesions remain or are not removed, they only reach thicknesses in the range of 5 to 10 mm even after a plurality of tapping operations. That is, the layer thicknesses of adhesions do not increase with multiple tapping operations.

The reasons for the spalling or the non-increasing layer thickness of adhesions in the presence of the refractory layer are presumably that, especially when admixing slag in the adhesions, the different thermal expansion coefficient leads to flaking off. As far as adhesions remain, they are melted off during immersion, so that the layer thickness of an adhesion can build up again only to the strength mentioned. The material of the tube 31 is preferably steel (eg S355-J2H) and the steel tube has a layer thickness in the range of 15 to 60 mm, preferably 20 to 40 mm, for example 25 mm. As already described, the solution described is particularly advantageous in quasi-continuous charging. The finening is done in the oven. Among other things, the temperature of the molten bath is increased from about 1500 ⁰ C to about 1620 ⁰ C in a 100 t oven in a time of about 6 min in particular the temperature of the molten bath. This is the normal tapping temperature. In a normal oven, the oven is tilted to cut off about 5 ° to 10 °, often 8 °. At this tilt angle, it is not possible to leave the electrodes in the oven. With the described solution, tilting is not necessary so that the electrodes can continue to be operated during parting off. Thus, an additional saving in the non-productive time is possible. For example, you can start with the tapping at a molten bath temperature of 1580 to 1600 ⁰ C, depending on the size of the furnace, and continue to operate the electrodes at full power, so that during the tapping of about 3 minutes at 100 t furnace or For a further 5 minutes in the case of a 160 t oven, continue to heat the part of the molten bath which is still in the oven during parting and overheat to 1650 or 1660 ° C. The first tapped material with the temperature of about 1590 ⁰ C and the last abgeochochene material with a temperature of about 1650 to 1660 ° C and the meantime tapped quantities with temperatures in between mix after tapping in the pan, so that an average temperature at the desired about 1620 ⁰ C is achieved. This means that part of the finishing time can be cut-off time at the same time, so that approx. 2 minutes of non-productive time can be saved. That is, in Fig. 9, t ₀ can be pushed closer to t _A.

For all ranges, it is explicitly emphasized that all intermediate values and individual values are also disclosed as upper and lower limits of ranges. This means that not only 200 mm / s, 300 mm / s or 400 mm / s are disclosed as lower or upper limits for traversing speeds, but also all intermediate values such as 210 mm / s, 220 mm / s, etc. without these are expressly mentioned.

The same applies expressly for the time and length information.

Of course, the described devices and methods can also be used when the furnace vessel is tilted for parting off. The oven vessel is normally tilted 4 to 6 degrees from the horizontal and the tipping back takes between 3 and 10 seconds, normally about 5 seconds. In this case, with the tipping back from the time t | from Fig. 9, so the sealing of the tap opening to be started. Of course, a beginning after ti is also possible, for example, at time t ₂ (or t ₃ , t _v , U, h, or even later). Depending on when the tilting back is started, it may even be possible to dispense with the rapid retraction of the sealing and filling tube 31. At the start of the tipping back at ti, the residence time of the sealing and filling pipe 31 in the residual molten bath is significantly less than 10 s, normally even less than 6 s.

aspects:

The teachings of the following may be claimed separately or as claimed in the claims or other parts of the original disclosure.

An apparatus for temporarily sealing a tapping opening (12) having a first inner diameter (d3) and provided in the bottom (10, 1 1) of a metallurgical furnace (100) and for decaying the tapping opening (12) with a free-flowing refractory Mass (VM), with

a sealing and filling pipe (31) having a first length (li) and a lower opening (3 Iu) and an upper opening (31 o),

a first container (32) for filling compound (VM),

an opening and closing device (33), and

a hoist (40),

in the

the sealing and filling tube (31), the first container (32) and the opening and closing device (33) are fastened to the lifting mechanism (40) such that the first container (32) interposes the opening and closing device (33) is connected to the upper opening (31o) of the sealing and filling pipe (31) in such a way that the connection through the opening and closing device is under the control of a control device and can be closed,

the sealing and filling tube (31) has on its underside an outer diameter (d2) which is greater than the first inner diameter (d3), and at least the bottom and the inside of the sealing and filling pipe is at least up to a minimum height (h ₅ ) of a metallic material having a melting point> 1750 ° C and a minimum thickness of 50 microns. 2. sealing and filling device according to aspect 1, wherein

the hoist for facilitating a method of the sealing and Verfüllrohrs (31) in the longitudinal direction thereof at a speed> 200 mm / s is formed.

3. sealing and filling apparatus according to aspect 1 or 2, wherein

on the underside of the sealing and Verfüllrohrs (31) a sealant (34) is mounted, which has a height in the longitudinal direction of the sealing and filling pipe of at least 20 mm.

4. sealing and filling device according to one of aspects 1 to 3, in which

at least the underside and the inside of the sealing and Verfüllrohrs (31) at least up to the minimum height (h ₅ ) have a hard chrome coating as the metallic material.

5. sealing and filling device according to one of the aspects 1 to 4, in which

at least the bottom and the inside of the sealing and Verfüllrohrs (31) at least up to the minimum height (hs) an electrodeposited metal coating having a thickness in the range of 100 to 1000 .mu.m, preferably 150 to 300 microns, as the metallic material.

6. sealing and filling device according to one of aspects 3 to 5, wherein

the sealant is formed of an elastic material, which is preferably selected from rubber, perfluoroelastomer, polyethylene or polytetrafluoroethylene.

7. sealing and filling device according to one of the aspects 1 to 6, wherein

the sealing and filling tube (31) has a second inner diameter (dl) which is greater than or equal to the first inner diameter (d3).

8. sealing and filling device according to one of the aspects 1 to 7, wherein

the lifting mechanism and a control device are adapted to measure a travel path of the sealing and filling pipe in the longitudinal direction thereof and to increase the travel speed in longitudinal direction. direction of the same as a function of the measurement to be controlled so that when lowering the sealing and Verfüllrohrs (31) a final distance <50 mm is covered before the sealing with reduced travel speed. 9. sealing and filling device according to one of the aspects 2 to 8, wherein

the lifting mechanism is designed for active operation of the sealing and filling pipe (31) at a speed of> 200 mm / s, and / or in which the lifting mechanism is designed to move the sealing and filling pipe by the gravity of the mass of the seal and fill pipe (31) and optional additional weights.

10. sealing and filling device according to one of the aspects 1 to 9, wherein

the hoist is designed as a lifting and slewing gear.

11. sealing and filling pipe for temporarily sealing a tap opening (12) which is formed in a bottom (10, 1 1) of a metallurgical furnace, in which

at least the bottom and the inside of the sealing and filling pipe is at least up to a minimum height (h ₅ ) of a metallic material having a melting point> 1750 ⁰ C and a minimum thickness of 50 microns. 12. sealing and filling pipe according to aspect 1 1, wherein

13. sealing and filling pipe according to aspect 1 1 or 12, in which

at least the bottom and the inside of the sealing and Verfüllrohrs (31) at least up to the minimum height (h ₅ ) an electrodeposited metal coating having a thickness in the range of 100 to 1000 .mu.m, preferably 150 to 300 .mu.m, as the metallic material. 14. sealing and filling pipe according to one of aspects 1 1 to 13, wherein

the pipe is made of steel with a wall thickness in the range of 15 to 60 mm, preferably 20 to 40 mm, with a hard chrome layer having a thickness in the range of 100 to 300 μm at least up to the minimum height (h ₅ ). A metallurgical oven (100) having a bottom (10, 11) with a tapping opening (12) having a first inside diameter (d3) and a taphole opening and closing device (13) adapted to receive a predetermined tapping mass of liquid steel (FS), so that the liquid steel (FS) tapping mass has a first height (h ₆ ) above the tapping hole (12) prior to tapping, and one of the aspects is a sealing and backfilling device 1 to 10, wherein the first length (li) is greater than half of the first height (h ₆ ). It is explicitly pointed out that all features disclosed in the description and / or the claims are considered separate and independent of each other for the purpose of original disclosure as well as for the purpose of limiting the claimed invention independently of the feature combinations in the embodiments and / or the claims should. It is explicitly stated that all range indications or indications of groups of units disclose every possible intermediate value or subgroup of units for the purpose of the original disclosure as well as for the purpose of restricting the claimed invention, in particular also as the limit of a range indication.

Claims

claims

a sealing and filling pipe (31) having a first length (li) and a lower opening (3 Iu) and an upper opening (3 lo),

a first container (32) for filling compound (VM),

an opening and closing device (33), and

a hoist (40),

in the

the sealing and filling tube (31), the first container (32) and the opening and closing device (33) are fastened to the lifting mechanism (40) such that the first container (32) is interposed with the opening and closing device (33 ) is connected to the upper opening (3 lo) of the sealing and filling pipe (31) in such a way that the connection through the opening and closing device is under the control of a control device and can be closed,

the sealing and filling tube (31) has on its underside an outer diameter (d2) which is greater than the first inner diameter (d3), and

2. sealing and filling device according to claim 1, wherein

at least the bottom and the inside of the sealing and filling pipe is at least up to a minimum height (h ₅ ) of a metallic material having a melting point> 1750 ° C and a minimum thickness of 50 microns.

3. sealing and filling device according to claim 2, wherein

4. sealing and filling device according to claim 2 or 3, wherein at least the bottom and the inside of the sealing and Verfüllrohrs (31) at least up to the minimum height (h ₅ ) an electrodeposited metal coating having a thickness in the range of 100 to 1000 .mu.m, preferably 150 to 300 .mu.m, as the metallic material.

5. sealing and filling device according to one of claims 1 to 4, wherein the hoist is designed as a lifting and slewing gear.

6. sealing and filling device according to one of claims 1 to 5, wherein on the underside of the sealing and Verfüllrohrs (31) a sealant (34) is mounted, which has a height in the longitudinal direction of the sealing and Verfüllrohrs of at least 20 mm ,

7. sealing and filling device according to claim 6, wherein the material of the sealant is formed of an elastic material and / or is selected from rubber, perfluoroelastomer, polyethylene or polytetrafluoroethylene.

8. sealing and filling device according to one of claims 1 to 7, wherein the sealing and Verfüllrohr (31) has a second inner diameter (dl) which is greater than or equal to the first inner diameter (d3).

9. sealing and filling device according to one of claims 1 to 7, wherein the hoist and a control device are adapted to measure a travel of the sealing and filling pipe in the longitudinal direction thereof and to control the travel speed in dependence on the measurement such that at a lowering of the sealing and Verfüllrohrs (31) a final distance <50 mm before sealing with reduced travel speed is covered.

10. sealing and filling device according to one of claims 1 to 9, wherein the hoist for active method of the sealing and Verfüllrohrs (31) at a speed of> 200 mm / s is formed and / or in which the hoist to is designed to release a movement of the sealing and filling pipe in the longitudinal direction thereof by the gravity of the mass of the sealing and Verfüllrohrs (31) and optional additional weights.

11. Sealing and filling device according to one of claims 1 to 10, wherein the hoist for active method of the sealing and Verfüllrohrs (31) in the vertical direction in the direction of gravity at a speed of> 200 mm / s is formed.

A metallurgical oven (100) having a bottom (10, 11) with a tapping opening (12) having a first inside diameter (d3) and a tapping hole opening and closing device (13) adapted to receive a predetermined tapping mass of liquid steel (FS) such that the liquid steel (FS) tapping mass has a first height (h ₆ ) above the tapping hole (12) prior to tapping, and the sealing and filling apparatus of any one of claims 1 to 1 1, wherein the first length (10 of the sealing and Verfüllrohrs (31) is greater than half of the first height (h ₆ ).

13. A method of tapping off a metallurgical furnace having a tapping opening (12) in a bottom (10, 11) and adapted to receive a predetermined tapping mass of liquid steel (FS) having a first height Qi before tapping ₆ ) above the tapping opening (12) using a device for temporarily sealing the tapping opening and filling the tapping opening with the filling compound (VM), which has a sealing and filling pipe (31) with a first length (li) which greater than half the first height (h ₆ ) is, with the steps:

a) tapping the tapping mass from liquid steel (FS), leaving a residual sump of liquid steel (FS) of a second height (h ₂ ) above the tapping hole (12); b) lowering the sealing and filling pipe (31) such that the underside of the sealing and filling pipe seals the tapping opening (12);

c) closing the tapping opening (12) through the tapping hole opening and closing device (13); and

d) filling the tapping opening (12) with a free-flowing refractory mass (VM), which falls through the sealing and filling tube under gravitational effect in the tapping opening (12),

characterized,

that the sealing and filling pipe is lowered through the residual sump at a speed> 200 mm / s, and

the second height (h ₂ ) is <500 mm.

14. The method of claim 13, wherein

a drop height of the free-flowing refractory mass (VM) is such that the fall time is <5 s, preferably <2 s.

15. The method according to claim 13 or 14, wherein

the lowering of the sealing and filling pipe (31) over the last distance before sealing, which is <50 mm, with reduced speed <200 mm / s.