WO2003035913A1

WO2003035913A1 - Method and device for cooling ladle slag and converter slag

Info

Publication number: WO2003035913A1
Application number: PCT/DE2002/002642
Authority: WO
Inventors: Egon Evertz; Rolf Seybold
Original assignee: Egon Evertz K.G (Gmbh Und Co.)
Priority date: 2001-09-28
Filing date: 2002-07-18
Publication date: 2003-05-01
Also published as: DE10148152B4; DE10148152A1

Abstract

The invention relates to a method and a device for cooling ladle slag and/or converter slag by means of heat abstraction. According to the invention, the slag is cast in a collecting container, and at least one immersion body consisting of copper or a copper alloy is then immersed into the slag which is still in a liquid form. The low temperature of the immersion body enables it to absorb part of the heat of the slag. Once the heat compensation is at least essentially completed, the immersion body is removed from the slag.

Description

description

Method and device for cooling ladle and converter slag

The invention relates to a method for cooling ladle and / or converter slags by means of heat removal. The invention further relates to an apparatus for performing this method.

During the production of pig iron or other metallurgical processes, slags accumulate on the bathroom mirror, which contain undesirable companions for the end products and are therefore removed from time to time as required. The quantities of slag are collected in a collecting container which, according to the prior art, is emptied by pouring out. In the simplest case, the slags are poured into a bunker or on a heap and brought to cool and solidify by spraying with water. There is a non-negligible risk of explosion from both the release of hydrogen and the spontaneous overheating of the water vapor. Although the risk of explosion can be reduced by using large water flows, precautions must then be taken in order to discharge the large amounts of water again. Correspondingly large, space-consuming decanting tanks or drainage drums can be used for this. In the case of smaller amounts of slag, however, such measures, including the associated costs, prove to be too expensive.

In addition, in the case of the above-described explosive processes, it is also unavoidable to throw away liquid, partially solidified or solid slag constituents, which can pose a considerable risk to the operating personnel. Finally, the described water cooling also creates other, sometimes harmful gases that flow freely into the environment. From WO 00/00649 a device for wet granulation of liquid slag is known, which comprises a granulating basin with an injection device for the granulating water, a decanting basin separated from the granulating basin, in which the slag settles as granulate, and a device for introducing the granulate water Contains mixture from the granulating basin into the decanting basin, the device for introducing the granulate-water mixture from the granulating basin into the decanting basin comprises at least one elongated distribution channel which extends over the decanting basin. The underside of the distribution channel has flow agents distributed over its length over the granulate / water mixture. In the decanting basin, a vertical, downwardly open inflow shaft is formed below the at least one distribution channel, into which the outflow means for the granulate / water mixture open. This device and the method that can be carried out with it are also relatively complex.

WO 00/50647 discloses a process for granulating and comminuting liquid slags, in which liquid slags are introduced into an expansion chamber and a cooling zone, the liquid slag being sucked into an expansion chamber which is under vacuum and transported into the cooling zone with a propellant jet becomes. High-pressure water with a pressure of over 50 bar or superheated steam with temperatures of over 800 ° C is used as the driving jet.

WO 99/42623 describes a method for granulating and comminuting liquid slags, in particular blast furnace slags, with water, in which a pressurized water jet is directed into the slag. With the pressurized water jet, gases, in particular oxygen, air and / or oxygen-inert gas mixtures, are to be dissolved in the slag prior to the discharge, iron portions of the slag being oxidized quantitatively, the slag being pressed out through the slag opening with the pressure of the pressurized water, and as the jacket of the Pressurized water jet is ejected. Pressurized water pressures to be applied are between 35 bar and 160 bar. In the case of the last-described processes, too, a high level of equipment and costs must be incurred, which is economically unacceptably high for smaller quantities of slag. It is an object of the present invention to provide a method and a device of the type mentioned at the outset in which effective, efficient cooling is ensured in the simplest way. The method and the device required to carry it out should in particular enable inexpensive work. Finally, the small space requirement in the steelworks has to be taken into account.

This object is achieved by the method according to claim 1. According to the invention, the slag is poured into a collecting container, after which one or more immersion bodies made of copper or a copper alloy are then immersed in the still liquid slag, which absorb part of the heat of the slag due to their lower temperature and that after at least one im heat balance between the slag and the immersion body (s), the immersion body (s) being withdrawn again from the slag.

The advantage of this process is that, due to the good thermal conductivity of copper, rapid heat transfer from the slag to the immersion body is possible, which is accompanied by a significant drop in temperature of the slag. In principle, it is no longer even necessary for the immersion body (s) to be completely immersed in the slag, since the time until the next slag tapping is sufficiently long to bring about the desired slag cooling. The size of the immersion body and thus the heat absorption capacity depends on the amount of slag to be cooled and the lowering of the slag temperature that is desired. By appropriately dimensioning the immersion body, the slag temperature can easily be reduced from originally about 1200 ° C to 600 ° C.

According to a development of the method, the cooling process is repeated several times, the immersion body or bodies being cooled between the individual dives, preferably in a water bath. This measure allows the temperature of the slag to be gradually reduced further in repeated operations. According to a further embodiment of the invention, the slag collecting container has a holding capacity for several, separately occurring slag batches which are entered intermittently at intervals until the filling is at least substantially complete, the immersion body or the immersion bodies being immersed one or more times between the individual filling processes /become. If, in practice, it is assumed that a batch of slag accumulates approximately every 30 minutes and it takes up to 6 minutes to transfer it to the collecting container, there are 24 minutes between the individual slag empties in which cooling can be carried out using an immersion body made of copper. After the first slag emptying, the slag temperature of the first batch can be cooled to significantly lower temperatures than 300 ° C., for example by repeated dives. The next batch of slag is then added to the cooled amount of slag already present in the collecting container, the slag filling preferably being carried out without major mixing with the slag already present in the collecting container. This newly filled amount of slag has a temperature on its surface which is also about 1200 ° C. The immersion body, which has a temperature corresponding to the ambient temperature, is now at least partially immersed in the uppermost slag layer, as a result of which heat is transferred to the immersion body and the slag temperature is accordingly reduced. This diving process can also be repeated several times, with the diving body being cooled in a water bath between the individual dives. Depending on the absorption capacity of the collecting container and the discontinuous amount of slag, four batches can be taken up and cooled, for example, until the collecting container is filled, before the collecting container with the significantly cooled slag is replaced by a new empty collecting container.

As already indicated above, the immersion body is adapted in terms of its geometric dimensions and / or its heat capacity and thermal conductivity to the respective amount of slag batch to be cooled. Ideally, the immersion body is made of copper or a copper alloy. The immersion body can, for example, have a cuboid shape, the immersing cuboid surface is only slightly smaller than the cross-sectional area of the receptacle. Alternatively, it is also possible to use a plurality of immersion bodies hanging from a lifting device in the form of balls, cubes, with a teardrop shape or other geometry.

To carry out this method, the device described in claim 5 is used, in which a collecting container is arranged below a pouring device for the resulting slag, which is preferably movable. In addition, at least one immersion body attached to a lifting device is provided, which can be lowered into the interior of the collecting container. According to a further embodiment, the lifting device can be moved horizontally and lowered into a coolant bath, preferably a water bath. The latter development enables the dipping process to be repeated several times between the individual filling processes of the collecting container to successively lower the temperature of the slag.

As already mentioned above, the immersion body is preferably a plate or a ball and has dimensions to essentially cover the inner cross section of the collecting container. This provides the largest possible area of the immersion body over which heat transfer can take place. Several individual immersion bodies of the same or different sizes can be attached to the lifting device, e.g. several pear-shaped immersion bodies, at different heights, so that the immersion bulbs hanging below immerse completely and the ones above them only partially in the slag bath.

Further advantages and embodiments of the invention are shown in the drawings. Show it

Fig. 1 is a schematic diagram with a pouring spout, a movable collecting container and indicated immersion bodies and

Fig. 2 shows an alternative embodiment of a device with several

Body diving. The discontinuously occurring slag is poured from a collecting container 10, possibly by means of a scraper, into a collecting container 11, which is designed here as a movable carriage (see arrow 12). A cuboidal immersion body 14 is then immersed in the first batch of slag 13 by means of a lifting device (not shown), which absorbs part of the heat quantity of the slag. Since the immersion body consists of a solid copper body, the heat balance takes place relatively quickly. The immersion body, which in the arrangement shown in FIG. 1 is a cuboid, remains immersed until heat compensation between the slag and the immersion body has taken place at least approximately. Since there is still sufficient time regularly before filling with the next batch of slag, the immersion body is lifted out of the interior of the collecting container after the first dive, for example by means of an electric pulley block (lower belt trolley), moved sideways and lowered into a water bath (not shown) , after which the dive is repeated several times according to the time available until the next batch of slag and the desired slag temperature.

The next batch of slag can then be poured into the collecting container 11, which is cooled in the same way by at least one dive. The process is repeated until the holding capacity of the collecting container 11 is reached, after which the collecting container is moved away and replaced by a new collecting container.

The particular advantage of the method according to the invention or the device according to the invention is that a considerable number of movable collecting containers can be saved, since the slag that has been removed has already undergone a temperature reduction which enables problem-free further processing into slag granules. Downtimes for intermediate cooling of the slag before it is processed and processed into granules can thus be saved.

With regard to the shape, a diving body according to FIG. 2 can also be used instead of the diving body 14. In this case, a Hener support beam 15 as a suspension for several, here approximately spherical immersion bodies 16 and 17, which have a different size in the illustrated embodiment. In the exemplary embodiment shown in FIG. 2, the immersion bodies are arranged in a staggered manner in height. The size of the immersion body 14 or the immersion bodies 16, 17 ultimately depends on the respective amount of slag to be cooled and its temperature.

The immersion bodies preferably consist of a solid copper material or a suitable copper alloy, which ensures that no slag bakes on the immersion body or the immersion bodies.

Claims

claims

1. A method for cooling pan and / or converter slags by means of heat removal, characterized in that the slag is poured into a collecting container (11) and then one or more immersion bodies made of copper or a copper alloy are poured into the still liquid slag (13) (14, 16, 17) are immersed, which absorb part of the heat of the slag (13) due to their lower temperature, and that after an at least substantially equalization of heat, the immersion bodies (14, 16, 17) come out of the slag (13 ) are pulled out.

2. The method according to claim 1, characterized in that the cooling process is repeated several times, the immersion bodies (14, 16, 17) being cooled between the individual dives, preferably in a water bath.

3. The method according to claim 1 or 2, characterized in that the collecting container has a holding capacity for several, separately occurring batches of slag and is discontinuously poured with slag until at least substantially complete backfilling, the immersion bodies (14, 16, 17) is immersed one or more times.

4. The method according to any one of claims 1 to 3, characterized in that one or more immersion bodies (14, 16, 17) of a geometry and / or a thermal capacity and thermal conductivity are used, which is adapted to the respective amount of slag batch.

5. Device for performing the method according to one of claims 1 to 4, characterized in that below a pouring device (10) for the resulting slag is arranged in a collecting container (11), which is preferably movable, and that at least one immersion body (13, 16, 17) attached to a lifting device can be lowered into the interior of the collecting container.

6. The device according to claim 5, characterized in that the lifting device can be moved horizontally and the immersion body (14, 16, 17) can be lowered into a coolant bath, preferably a water bath.

7. The device according to claim 5 or 6, characterized in that the immersion body is a plate (14) or a ball (16, 17) and preferably has the dimensions to substantially cover the inner cross section of the collecting container (11).

8. Device according to one of claims 5 to 7, characterized in that a plurality of individual plungers (16, 17) of the same or different sizes are attached to the lifting device.