DE2949998A1 - METHOD FOR PRODUCING A MODULE UNIT FOR THE WALL OF A METALLURGICAL FURNACE - Google Patents

Description

Method of manufacturing a building block unit for the wall of a

metallurgical furnace

The invention relates to a method for producing a building block unit for the wall of a metallurgical furnace.

In metallurgical furnaces such as those used for smelting iron or refining molten metal, the inner walls are lined with a layer of fire-resistant or heat-resistant material, which is provided by separate cooling devices is protected. Various techniques are known for cooling such a heat-resistant layer, including the use of cooling blocks or cooling boxes provided with stave-like cooling rods, which are being used to an increasing extent in industry (these are called "stave-cooler" in English).

A vertical cross-section through the fireproof or heat-resistant wall of a FIG. 1 (a) shows a blast furnace and FIG. 1 (b) shows a partial enlargement thereof. As can be seen from these figures, the heat-resistant Wall of the blast furnace Rows of cooling blocks or cooling box 1 with cooling tubes running like staves for cooling the furnace. Each of the cooling blocks 1 is potted with a cooling pipe 9. Each cooling block 1 is attached to the inner wall of a shell 2 and to the Inside wall of the cooling block 1 is a heat-resistant stone 3, the is attached with mortar 10 serving as an adhesive. The furnace is cooled with water, which passes through the pipe 9 to remove the heat derive from inside the furnace. The cooling tubes 9 of the individual Cooling blocks 1 are connected to one another by connecting pipes 11

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ORIGINAL INSPECTED

FIG. 1 (c) shows an embodiment of the cooling blocks 1, seen from the shell 2.

To line a blast furnace with heat-resistant walls of the type described above, it is generally necessary to install the rows of cooling blocks 1 and the heat-resistant bricks 3 separately. If the effective cooling surface of the cooling block 1 is flat, it is not necessary to use special techniques when installing the heat-resistant walls. However, if the surface in cross section has the shape of the Greek capital letter ^r (inverted L) as shown in Fig. 4 or the Greek capital letter Π as shown in Fig. 2 (a), or some other shape with protrusions, then it is necessary to to arrange heat-resistant stones 3 of different dimensions on the inner surface of the cooling block. Furthermore, a special level of technical skill is required to install heat-resistant walls that have a minimum of gaps. In Fig. 2 (b), more protrusions are shown on the inner surface of the cooling block than in Fig. 2 (a).

To solve these problems encountered when installing with cooling devices provided heat-resistant walls occur, two modes of operation have been proposed. One of these is a cooling block to pour with a stave-like cooling rod and a heat-resistant layer of one on its effective cooling surface apply pourable refractory material. The other way of working is by fitting refractory stones into the on the effective cooling surface of the cooling block existing recesses to form a heat-resistant layer. The one made according to the first working method heat-resistant layer can be dried, but it is very difficult to burn this layer. The required Burning of the heat-resistant wall installed according to this method of operation

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ORIGINAL INSPECTED

takes place through the heat of the furnace when heating, however it often happens that the necessary for the specific heat-resistant layer Conditions of the firing atmosphere or temperature are not met. For example, it is desirable to have a refractory material fire from a malleable silicon carbide based material in a reducing atmosphere. The control of the for however, conditions suitable for such a reducing atmosphere are very difficult in ordinary industrial operation of the furnace to realize. When producing the cooling block according to the second procedure, however, the heat-resistant ones are formed Layer of refractory or heat-resistant bricks are used, so that the conditions for immediate use of the stove are met. For the production close contact between the refractory layer and the effective effective cooling surface of the cooling block and to achieve a good attachment of the heat-resistant layer on the cooling block is not only a precise processing of the heat-resistant stones, but also the use of a complex holding device is required. Furthermore, in the course of the use of the heat-resistant walls, the binding capacity of the mortar or other substance is gradually lost, so that after a long period of time the heat-resistant stones are only in their Layers are held. If a stone is worn out, the bond between the other stones is lost, which is often the case leads to the fact that the stones come loose one after the other from the cooling block.

The object of the invention is accordingly to provide a method for manufacturing to provide a building block unit for the wall of a metallurgical furnace, which with the aforementioned disadvantages of normal procedures are not affected.

The solution to the problem arises from the claims.

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ORIGINAL INSPECTED

manufactured]
The inventive / Tiausteeinuneinheit consists of a fired heat-resistant layer and a cooling block or cooling box with stave-like cooling rods, the cooling system is formed together with the heat-resistant layer, so that an effective, one-piece cooling surface with the heat-resistant layer is created.

Since in detail the building block unit produced according to the invention consists of a layer of cast refractory material which is molded in one piece with the cooling block, the Do not easily detach the layer from the cooling block. Furthermore, before the cooling block is poured, the pourable refractory layer is sufficiently applied fired to have the requisite refractory properties. Another advantage of the building block unit obtained in this way is that it can be easily produced on an industrial scale, that is, in required quantities. According to the invention In the process, a pre-molded and fired refractory block is used as part of the mold and it has the cast cooling block with stave-like cooling rods on a heat-resistant layer, which with the inner surfaces of the cooling block is in one piece. The heat-resistant layer on the inner surfaces of the cooling block is consequently not only reinforced, it is located also in close contact with the cooling block. In an additional way, the cooling block with stave-like cooling tubes results uniform cooling and it prevents the development of local thermal stresses inside the refractory layer, so that the building block unit produced according to the invention for a furnace wall is highly resistant to thermal cracking.

The essence of the invention thus consists of a method for Manufacture of a building block unit for the wall of a metallurgical furnace, which has process steps in which a castable,

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Refractory or refractory material is formed into a refractory or refractory layer and fired to form a wall of a mold Pouring a cooling block or cooling box with stave-like cooling tubes, one or more tubes through which a Coolant flows, to be placed in the internal space provided in the mold, and for casting a cooling block or cooling box with cooling tubes, which connects to the refractory or heat-resistant layer to form a building block unit for a furnace wall, a molten one Metal is poured into the interior.

Based on the figures, in particular Figures 2 (a) and (b) and figures 3 and 4 the invention is explained in detail. Show it:

Fig. L (a) shows a longitudinal cross-section through part of a blast furnace, its heat-resistant walls with cooling blocks or cooling boxes with stave-like cooling rods are provided;

FIG. 1 (b) is an enlarged view of section A of the FIG refractory walls shown in Fig. 1 (a);

Fig. L (c) an example of the cooling blocks in section A, of which Shell 2 of the blast furnace viewed from here;

Fig. 2 (a), cross sections through various embodiments

J _{4 of} a building block unit produced according to the invention

for a furnace wall, and

Fig. 5 cross sections of a casting mold to explain the in

the invention taking place casting of the cooling block, which is part of the manufactured according to the invention

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Building block unit for the wall of a metallurgical furnace.

In the figures, a cooling block or cooling box with a barrel stave running cooling tubes denoted by the number 1 and a heat-resistant layer by the number 4. For making the heat-resistant Layer 4 becomes a castable refractory or refractory material more suitable Composition formed into a layer and then fired. The castable refractory material is selected depending on the The type of metallurgical furnace and the location where the refractory material is to be used. Forming the material into a layer takes place by conventional molding processes for refractory material, e.g. by a vibration molding process or a compression molding process.

The area of the effective cooling surface of the cooling block 1 can be by making the surface 6 of the heat-resistant layer 4 uneven, as shown in FIGS. The uneven surface 6 serves that due to different thermal deformation of the heat-resistant layer 4 and the cooling block to lessen the problem that arises. Is the surface of the refractory layer with angled ribs, e.g. ribs with a rectangular cross-section provided, as shown in Figures 2 (a) and (b), then the differential thermal deformation to form a, e.g. Crack 15 starting from a corner. To prevent this from happening, the ribs on the surface of the heat-resistant layer can be covered with a Heat-resistant material, e.g. ceramic fibers, which absorbs the thermal expansion, must be covered before the cooling block is cast will.

Another way of reducing the problem caused by thermal deformation is to use the

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heat-resistant layer 4 with one extending in the direction of its thickness To provide expansion joint. The expansion joint is also effective in preventing chipping or spallation of the heat-resistant material Limit layer.

If the cooling block 1 to be cast is to have an effective cooling surface 5 of asymmetrical, special shape, e.g. that of the Greek capital letter Γ (inverted L) or the Greek capital letter Π, then the surface 6 of the heat-resistant layer is shaped in a corresponding manner as shown in Fig. 4 or Fig. 2 (a) and (b) is shown.

The heat-resistant layer 4 described above can be shaped in such a way that one or more connecting pins 8 are embedded in its surface 6. The connecting pins 8 can consist of one Consist of metal and have the shape shown in Figures 2 (a) and (b) or Figure 3 or consist of a heat-resistant material and the have the shape shown in FIG.

The one shaped to meet the above requirements The refractory layer is then fired under the atmosphere and temperature conditions appropriate to the composition of the heat-resistant material are suitable. The metallic connecting pin 8 is the thermal effect during firing exposed, but it does not lose its functionality as a pen.

Fig. 5 explains the production of the cooling block according to the invention Procedure. The fired heat-resistant layer 4 is placed on the bottom of a generally designated 13 in the figure provided casting mold for the cooling block. A cooling pipe 9 through which a cooling medium such as water during the use of the cooling

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29A9998

blocks is circulated in the inside of the mold formed interior 12 introduced. A molten metal such as iron or copper is poured into the mold, after which a Solidification of the metal takes place.

In FIG. 4, the numeral 7 represents one on the heat-resistant layer 4 provided expansion joint.

While Fig. 5 shows an embodiment in which the heat-resistant Layer 4 is inserted into the casting mold 13, FIG. 6 shows a further embodiment in which the heat-resistant layer 4 has a Part of the mold 13 forms.

The invention will now be based on the following exemplary embodiment will be explained in more detail. The exemplary embodiment is given here for illustrative purposes only and is in no way intended to denote the Limit the scope of the invention.

Example: Manufacture of a cooling block with dimensions of 600 χ 1400 mm with cast-in pipes

A castable silicon carbide-based refractory material was made introduced into a mold measuring 600 χ 700 mm. A shaking force (frequency 60 Hz, 7 times the acceleration due to gravity) was applied to the casting mold. brought into action to make the pourable material flow. Under a pressure of 300 kPa the pourable Material formed into a heat-resistant sheet 200 mm thick and having a Π shape as shown in Fig. 2 (a). In additional Thus, connector pins were partially embedded in the refractory layer as shown in Fig. 2 (a). The heat-resistant material was thoroughly fired at 1300 ° C.

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Two such fired refractory pieces were placed side by side on the bottom of a mold with the ribbed side up. Cooling tubes were placed in the mold and a surrounding sand mold was made. In order to avoid breaking the ribs of the heat-resistant layer due to the contraction (contraction factor about 8-12 / 10OC) that occurs during the solidification of the cast part (e.g. cast iron), the ribs were covered with a sufficient amount of heat-resistant fibers to prevent the possible contraction of the cast metal to compensate. After completing this preparatory work, the refractory layer was heated to 600 ° C. with a burner, and malleable molten iron was poured into the mold to produce a casting 200 mm thick. After the final shaping, the casting was annealed at 600 ° C. for a period of 6 hours in order to relieve the remaining thermal stresses.

A test piece was cut from the produced cooling block to determine any cracking that might have occurred during the casting process. However, no cracking was found. The cooling block was installed on the inner wall of the shell in the lower part of the shaft of a blast furnace. In comparison with a heat-resistant wall (based on aluminum oxide, 500 mm thick), which was combined with a cooling block produced by the usual method and had a shelf life of only 8 months to 1 year and 2 months, the heat-resistant layer of the method according to the invention had manufactured cooling blocks show less wear and tear and lasted three years of continuous use. A cooling block in which a heat-resistant layer had been produced by fitting refractory bricks (based on silicon carbide, 200 mm thick) into recesses in the effective cooling surface, proved to be just as good as the cooling block produced according to the invention up to 1 1/2 Years after commissioning. After that, however, suddenly

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borrowed the refractory layer from the surface of the cooling block. the The reason for this was possibly a loss of the binding force between the refractory bricks, so that when they loosened of a worn stone, a neighboring stone also loosened, after which several stones loosened one after the other.

In the method according to the invention for producing a building block unit for the wall of a metallurgical furnace, as described above, the surface 6 of the heat-resistant layer 4 serves as part a casting mold into which a molten metal is poured to cast a cooling block, so that no special processing, such as cutting, is required to establish close contact between the surface 6 of the refractory layer 4 and the to produce effective cooling surface 5 of the cooling block 1 and to achieve effective cooling of the heat-resistant layer 4. Because the Cooling block 1 is poured together with the connecting pins located therein, these are firmly connected to the heat-resistant layer 4, whereby the useful life of the resulting refractory lining of the metallurgical furnace is extended. There in addition the refractory layer 4 is made by molding and firing a castable refractory material, the one with the refractory Layer 4 provided cooling block 1 immediately as a building block unit or component use for the refractory wall or lining of a metallurgical furnace.

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Claims (7)

LiEDL, NÖTH, ZEITLEÄ Patentanwälte 8000 Munich 22 Steinsdorfstrasse 21-22 ■ Telephone 089/22 9441 NIPPON STEEL CORPORATION 6-3, 2-chome, Ohtemachi, Chiyoda-ku, Tokyo, JAPAN Method for manufacturing a building block unit for the wall of a metallurgical furnace Patent claims: 1. A method for producing a building block unit for the wall of a metallurgical furnace, characterized by method steps, at them - a castable, refractory or heat-resistant material to a heat-resistant one Layer is formed and fired, the one wall of a mold for casting a cooling block with a barrel stave Cooling linkage forms, - one or more pipes through which a coolant flows into the be arranged in the shape of the interior space, and - for casting a cooling block with cooling rods, which is connected to the heat-resistant layer to a building block unit for a furnace wall 9493 J / Br. 030025/0810 ORIGINAL INSPECTED connects, a molten metal is poured into the interior. 2. The method according to claim 1, characterized in that that the surface of the heat-resistant layer to be brought into contact with the cooling block has ribs, grooves, furrows or projections is provided. 3. The method according to claim 1, characterized in that the heat-resistant layer with at least one in the direction of the thickness expansion joint running through the refractory layer. 4. The method according to claim 1, characterized in that when forming the heat-resistant layer in the layer surface, that is to come into contact with the cooling block, one or more connecting pins are inserted. 5. The method according to claim 1, characterized in that the cast cooling block for reducing occurred during casting Stress is subjected to a heat treatment. 6. The method according to claim 2, characterized in that the ribs have a rectangular cross section. 7. The method according to claim 6, characterized in that the rectangular ribs are covered with heat-resistant fibers, which are able to absorb a contraction of the molten metal occurring during the casting of the cooling block. ⁹⁴⁹³ 030025/0810