WO2009018796A1

WO2009018796A1 - Device for slag-free tapping or for transferring a melt

Info

Publication number: WO2009018796A1
Application number: PCT/DE2008/001144
Authority: WO
Inventors: Norbert Uebber; Manfred Schubert
Original assignee: Sms Siemag Ag
Priority date: 2007-08-04
Filing date: 2008-07-09
Publication date: 2009-02-12
Also published as: DE102008008033A1

Abstract

2.1 The invention relates to a device for slag-free tapping or for transferring a melt from a metallurgical vessel (1, 2, 3) into a different metallurgical vessel having a siphon-like, inverted U-shaped configuration, wherein the siphon (4) comprises an inlet channel (5), a connecting channel (6) and an outlet channel (7), and wherein the inlet channel (5) and the outlet channel (7) can be immersed into the discharging or receiving vessel. 2.2 The aim of the invention is to create such a device that it is easy to maintain and reliable, wherein at the same time interruptions in the operation for the exchange of a worn tapping system are to be avoided. In order to achieve this, the siphon (4) is configured as a separate, mobile unit.

Description

Device for slag-free tapping or for transferring a melt

Device for slag-free tapping or for transferring a melt from a metallurgical vessel into another metallurgical vessel, in particular from a tiltable or fixed electric arc furnace, in siphon-like design with the features specified in the preamble of claim 1.

In order to stave off slag-free, simple siphon punctures have been known for some time, but have largely been displaced by bottom taps for reasons of gas uptake of the melt during tapping and lower tilting requirements. In order to combine the advantages of both systems, Siphonabstiche were designed that open in a Bodenabstich (DE 102 23 906 A1).

There, a bay is specially designed or designed a separately attached bay, which adjoins a connecting wall of the lower vessel of the arc furnace and is connected via a tapping channel with this. In DE 102 23 906 A1 can be controlled at pressure and vacuum-tight coverage of this bay window, by controlling the gas pressure in the bay, the tapping speed of the melt or the tapping can be started or interrupted. Also known from EP 1 181 491 B1 is a metallurgical vessel in which a siphon is an integral part of the lower vessel part.

For the transfer of melt from a fixed metallurgical vessel in a subsequent vessel for the next metallurgical process of the University of Missouri RoIIa a cascaded arrangement of vessels is carried out, the fixed siphon-like vessel structures to be operated continuously.

In the concepts listed, the accessibility of the channels of the siphon for maintenance work is difficult to implement. It can not be ruled out that frostbites or washouts in the aforementioned systems lead to functional impairments and lengthy standstills. The integration of siphon systems (Missouri RoIIa) impairs the optimal metallurgical design of the vessels between the smelting aggregate and the distributor. In general, the integration of siphon systems into or onto the metallurgical vessels limits the freedom of design for process-optimized shaping of the metallurgical vessels.

The invention is therefore an object of the invention to provide a device of the type mentioned above for slag-free melt transfer with good maintainability and high availability, with which can continue to avoid business interruptions for the replacement of a worn tapping system. It should also be possible to use a fixed arc furnace.

This object is achieved in a generic device in that the siphon is designed as a separate, mobile unit. The essence of the invention thus consists in that the siphon for slag-free melt transfer is not firmly integrated into the vessel for melting or for the metallurgical work, so it is not firmly connected with this structurally, but is designed as an independent, independently movable or movable system ,

The melt flow can be introduced and maintained by means of a negative pressure in the channel and be interrupted again by releasing the negative pressure. In order to control the melt flow and to leave the melt level in the region of the refractory channel ends, it is proposed according to a preferred embodiment that at least one vessel is movable in height. The proposal is to make it possible that with the help of the siphon concept a slag-free tapping and / or a fixed arc furnace and generally a slag-free transfer of melt between metallurgical vessels is reliably enabled. Furthermore, the concept should in particular be implemented in a relatively simple way to electric arc furnaces, steel pans, etc. and allow easy maintenance and in particular a quick replacement of the siphon. The system is also intended to allow controllability of the melt flow between the vessels, in particular the beginning and end of the melt flow.

The invention will be explained in more detail with reference to the drawings.

The figures show schematically different variants of the device according to the invention.

According to FIG. 1, the transfer of a melt from an electric arc furnace 1 takes place into a first metallurgical vessel 2 and from there into a second metallurgical vessel 3. The siphon is designated in this and in all other figures with 4 and consists of an inlet channel 5, a connecting channel 6 and an outlet channel. 7

In this case, a siphon 4 is positioned with refractory lined channels over the two vessels such that the two ends of inlet and outlet channel 5, 7 protrude into the respective melt. Between the container to be emptied and to be filled 1, 2 there is a difference in height. To initiate the melt flow, a negative pressure is built up at the upper end of the outlet channel 7. The corresponding connection is numbered 8. The melt flow is determined essentially by the height difference between the melts in both vessels 1, 2 and the channel cross sections and can be varied to a certain extent by relative changes in the height of the vessels.

FIG. 2 shows the melt flow between two metallurgical vessels, in which the vessel to be filled is empty at the beginning and is filled from the arc furnace.

To generate a negative pressure in the outlet channel 7, to initiate the melt flow between the vessels, the channel end is temporarily sealed gas-tight in the vessel to be filled. The closure 10 can be realized for example by sheets or plates at the channel end, which are provided with sealing compounds. Release of the melt flow may be accomplished by actively removing or opening the shutter 10, by timely melting of the shutter, or by exceeding a metallostatic pressure threshold above the shutter. It should be noted that the possibly necessary residual evacuation of the melt channel takes place more quickly than the gas volume in the channel rises again by the start of the melt outlet. In order to immerse in the transfer of the melt only a small part of the outlet channel 7 in the melt, the vessel to be filled is movable in height and is lowered during the tapping process according to the melt flow steadily down. In principle, however, the outlet end of the melt or outlet channel 7 can also be located outside the melt of the vessel to be filled.

To detect the degree of filling of the melt channel 7, (as shown in Figure 3), for example, on a channel 11 at the upper end of the connecting channel 6, which is also used for evacuation, detected by means of a sensor 15, the height of the melt in the channel system. The detected ride height can be linked by a control unit 12 with the vacuum generation.

In order to support the melt flow in the channel, inert gas 13 can be introduced into the inlet channel 5 of the melt, similar to an RH system (FIG. 3). This accelerates the flow rate and increases the metallurgical purity.

In order to detect entrained slag, according to FIG. 4 a slag detection system 14 may preferably be installed in the inlet channel 5 (for example an induction coil around the channel). In the case of slag detection, the slag transfer can be reduced or avoided to a minimum by rapid gas filling of the melt channel. With conventional slag detection on the EAF, efficient intervention is significantly less favorable.

Another way to detect running slag when emptying a vessel is the detection of the course of the negative pressure in Evacuation channel. If slag is sucked in, this is reflected in a discontinuity of the pressure curve.

For preheating the melt channel in discontinuous use of the channel can be preheated with hot burner gases or spent, for example, in a preheating furnace.

In order to minimize the temperature drop of the melt during the transfer of the melt or to introduce additional heat into the melt, around the melt channel, such as the connecting channel 6, around an induction heater 9 can be installed, which can be carried out very effectively due to the constant Kanaiquerschnitts.

The ends of the channels 5, 7, which dip into the melts, should preferably be designed to be exchangeable quickly, since slag attachments can form here over time and the edges of the inlet opening are subject to wear. ^•

In an adapted embodiment of the tapping system described above, this can also be used for the slagging, e.g. a fixed arc furnace, are used. To detect the boundary layer between slag and melt, for example, the tapping system can be subjected to a gas pressure, wherein upon reaching the boundary layer of the gas pressure increases due to the higher density of the melt. In response to this signal, the system can then be slightly withdrawn, the vacuum for the suction of slag generated and thus the vessel to be detoxified.

The advantages that can be achieved with the device according to the invention can be summarized as follows: Reliable siphon operation when slag-free tapping an arc furnace or generally the melt transfer between metallurgical vessels, the siphon is easy to maintain and, if necessary, quickly replaced.

The transfer of the melt does not require a tilting movement.

When transferring the melt, the melt comes in no significant contact with the ambient air, so that the gas absorption is reduced or prevented.

There are no restrictions in the use of conventional vessels in the metallurgical vessels and also in the electric arc furnace, only minor modifications are necessary.

Due to the negative pressure and an optional injection of inert gas, the tapping process or the transfer of melt can be used to improve the metallurgical purity of the melt.

The height difference between the melt channel inlet and outlet can be made larger than the metallostatic height in the vessel to be emptied, so that with the same outlet cross-section, a larger mass flow can be achieved.

The melt can be purified with a customized system.

Claims

claims

1. A device for slag-free tapping or for transferring a melt from a metallurgical vessel (1, 2,3) in another metallurgical vessel with a siphon-like, inverted U-shaped configuration, wherein the siphon (4) has an inlet channel (5), a Connecting channel (6) and an outlet channel (7), and the inlet channel (5) and the outlet channel (7) are submerged in the dispensing or the receiving vessel, characterized in that the siphon (4) formed as a separate, mobile unit is.

2. Device according to claim 1, characterized in that with the outlet channel (7) is provided a controllable means (12) for generating a negative pressure in this channel, so that the melt flow introduced in the channel, maintained and interrupted by canceling the negative pressure again can be.

3. Device according to claim 1 or 2, characterized in that at least one vessel (1, 2) can be moved in height around the metallostatic height in the vessel to be emptied, so that a larger mass flow can be achieved with the same outlet cross section.

4. Device according to one of claims 1 to 3, characterized in that for detecting the degree of filling of the melt the Kanaisystem a sensor (15) is associated.

5. Device according to one of claims 1 to 4, characterized in that the detected height level control technology with the vacuum generation can be linked.

6. Device according to one of claims 1 to 5, characterized in that ^' in support of the melt flow in the inlet channel (5) inert gas (13) can be introduced.

7. Device according to one of claims 1 to 6, characterized in that for detecting entrained slag in the inlet channel (5) a slag detection system (14) is installed.

8. Device according to claim 7, characterized in that an induction coil around the inlet channel (5) or connecting channel (6) is arranged around for slag detection.

9. Device according to one of claims 1 to 8, characterized in that to minimize the temperature drop of the melt during transfer or for introducing additional heat into the melt around at least one of the channels an induction heater (9) is installed.

10. Device according to one of claims 1 to 9, characterized in that the ends of the inlet channel (5) and the outlet channel (7) are designed to be interchangeable.