JPH026808B2 - - Google Patents

Description

[Detailed description of the invention]

BACKGROUND OF THE INVENTION This invention relates to a vented refractory structure for use in blowing gas through the sheathing of a metal processing vessel. The oxygen injection method used for refining pig iron is the LD method,
This method is known as the LDAC method, OLP method, BOF method, etc., but from a metallurgical point of view, an improvement has recently been made in which a secondary gas such as nitrogen or argon is injected through the bottom of the converter under constant control. In other metal processing vessels, such as ladles or electric arc furnaces for post-treatment of steel, gas may be blown into the metal bath through the vessel bottom or coating on the vessel wall. Ventilated and refractory stones provided in the sheathing of the bottom or side walls of the container, through which gas is introduced, shall have a stability comparable to or greater than that of the ordinary refractory sheathing. There is a need. This is because, for example, it is difficult to remove heated breathable material from the bottom of the converter once it has deteriorated. Furthermore, it is desirable that the gas passageway be continuous, but also discontinuous if desired. That is, it is necessary to be able to operate the vessel without introducing gas, and to make it possible for the stone to be air permeable without any changes when the gas line is connected. Furthermore, the permeability of the stone must remain approximately constant throughout its service life and thus up to the end of the entire operation of the furnace. Previously known breathable stones made of porous refractory materials do not meet the above requirements. When used in smelting vessels, the stability (fire resistance) of the porous refractory material is less than that of the surrounding coating. In other words, the porous stone installed at the bottom of the oxygen converter becomes unusable after charging less than 100 times. In contrast, the conventional coating could be used for more than 500 charges. Furthermore, since porous stones do not provide discontinuous gas passages, metal penetrates into the pores of the stone and solidifies there. Therefore,
Even when the gas line is reconnected, the stone no longer has sufficient ventilation. Luxembourg patent application No. 81208 proposes a device suitable for installation at the bottom of a metal processing vessel for blowing process gas into the metal bath. This device has considerably improved stability compared to previously known permeable stones, yet allows the desired amount of gas to be injected. This device consists of a breathable fireproof structure, in which a number of flat, corrugated, tubular or linear separation members are embedded in the axial direction of the fireproof material, and the wall thickness of the separation members is reduced. This is what I did. In one embodiment of the structure, steel plates and segments or strips of refractory material are arranged alternately. In order to manufacture such a structure, it is necessary to cut the block made of refractory material into the required segments or strips, which makes it difficult to reduce the manufacturing costs. Because segments are generally small in thickness and large in length, segments made by compressing refractory materials are not easy to handle and are susceptible to breakage when fired. The aim of the invention is to improve the structure described above, to make it easier to manufacture and to increase the stability of the segments. Another object of the present invention is to improve the gas passage capacity while maintaining good stability of the structure. To achieve this objective, a refractory structure according to the invention comprises a passage formed along the face of at least two elongated refractory segments, said segments being spaced apart from each other by a thin metal layer. , forming a gas passage along the metal layer between the segments, each segment having a first longitudinal surface, a second longitudinal surface, a heating end surface and a cooling end surface, the first longitudinal surface of at least one of said segments a metal layer disposed on the longitudinal surface; a metal housing surrounding the segments and connecting the segments to each other and in sealing abutment with a second longitudinal surface of the segments; a gas distribution chamber formed in the cooled end surface of the segments; It is also characterized by comprising a connecting pipe communicating with the distribution chamber and means for supplying gas. In a first embodiment, the metal layer can be compression molded with a refractory material. The use of compression molded metal layers facilitates the manufacture and handling of segments of relatively thin thickness and large length. This is because the metal layer functions as a reinforcing member that increases the stability of the segment. By using segments or substructures with compression-molded metal layers, it is possible to easily produce a single structure from multiple segments. In that case, it is not necessary to install a metal plate inside. However, pairs of metal plates may be arranged between the segments if necessary. In a second embodiment, instead of being compression molded with the refractory material, the metal layer is placed adjacent to the refractory material. Regardless of whether the metal layer is compression molded with the refractory material or simply placed adjacent to the refractory material, the structures of the present invention may have longitudinal surfaces of the segments and the metal layer that are flat or grooved or corrugated, etc. It can be formed as a flat surface with a desired cross-sectional shape, and the segments can be formed from a single metal plate,
They can be placed adjacent to each other via a pair of metal plates and/or a spacing member. The spacing elements can be constituted by shaped seams or knots, by strips or wires of plate material, by combustible or vaporizable inserts, etc. In other embodiments, the metal layer is provided with a further metal layer, for example by welding, and no metal layer is interposed between mutually opposing longitudinal surfaces of adjacent segments. Desired cross-sectional shapes such as corrugations, ridges, grooves, etc. can be formed in the longitudinal surfaces of the segments of refractory material by cutting or milling. Of course, it is also possible to give the desired cross-sectional shape during the manufacture of the segments. That is, a shape opposite to the desired shape may be given to a press mold used when manufacturing the segments, and a longitudinal surface of the desired shape may be formed during compression molding of the segments. The segment, which is compression-molded together with a metal layer having a surface with a desired cross-sectional shape, is given a shape corresponding to the press mold, for example, a corrugated shape or a ridge, and the flat plate and the refractory material are simply charged into the mold. It can be easily manufactured. The desired shape is automatically given to the flat plate during press working. By assembling segments provided with metal layers of a desired cross-sectional shape, a passageway is created within the structure that allows the passage of gas, such that the desired shaped longitudinal surface of the segment is aligned with the flat or similar shape of the adjacent segment. adjacent to the longitudinal plane. The longitudinal surfaces of adjacent segments may or may not be provided with a metal layer. In another embodiment of the structure according to the invention, at least one pair of mutually adjacent metal plates is embedded within the segment. In this case, a spacing member can be placed between these metal plates as required. By appropriately determining the number of pairs of metal plates inserted into the structure and the shape of the spacing member, the gas passage characteristics can be changed as required. A structure in which pairs of metal plates are embedded is made by placing a part of the refractory material into a press mold, and then stacking pairs of metal plates that have the same length as the segments and a width less than or equal to the width of the segments. , can be easily manufactured by charging the remaining refractory material at the end. If two or more pairs of metal plates are to be buried within the structure, the above steps may be repeated. If press pressure is applied perpendicularly to the metal plate in this state, a structure with the desired structure can be obtained. When removed from the press mold, the metal plate is exposed at the end face of the structure and allows gas to pass through. A similar effect can be obtained by burying a single plate or tube with a bent cross section in place of the pair of metal plates. By appropriately determining the number of pairs of embedded metal plates within the structure, the gas passage characteristics can also be varied as required. Since the refractory material forming the structure corresponds to the material of the usual cladding, the stability of the structure is comparable to the cladding surrounding it, and there is no need to prematurely renew only the structure. As mentioned above, the structure can also be used in a gas-blocked state. That is, the metal that has entered the narrow gap between the metal plates is discharged from the structure when the gas supply is restarted, and the original gas passing performance can be obtained. This remains true throughout the life of the structure. Hereinafter, the present invention will be described with reference to illustrated embodiments. The structure 1 shown in FIG. 1 comprises a metal housing 2, for example consisting of plates welded together, which surrounds a total of 12 segments 3,
These segments are arranged in 6 rows and 2 columns. Each segment 3 has a compression-molded metal layer 4 which, at its unreinforced end face, closely adjoins the inner surface of the housing 2 via an intermediate connecting layer of mortar, not shown. This prevents uncontrollable and unwanted gas passage along the housing. A plate 5 is arranged between each row of segments 3 to allow gas to pass along this plate and the metal layer 4 of the segments 3. A pair of plates may be used instead of one plate 5. Furthermore, this plate 5 may be embedded in mortar. With the above-described configuration, gas flows along the metal layer 4 and the plate 5, and where the two metal layers are joined together, the gas also flows between the metal layers. Gas permeability can then be controlled by changing the gap between the combined metal layers. The segment 3 is spaced from the inner surface of the housing 2 by two edges 6 arranged on the inner surface of the housing 2 and preferably spot welded to the inner surface of the housing. An end plate 7 is hermetically welded to the cooling side, and a connecting pipe 8 is provided on this end plate. The space between the end plate 7 and the end face of the segment 3 serves as a gas distribution space. The unillustrated end face opposite the end plate 7 is the heating side of the structure and can be closed by a cover plate. Cover plates are used when the lining of the metal processing vessel surrounding the structure includes a carbon support such as tar. The cover plate is for preventing tar and the like from entering and adhering to the gas passage of the structure when the container is heated. At the start of operation, the cover plate melts to open the gas passage. A frame (not shown) is provided in the heated end region of the structure, by means of which the structure can be suspended from the hook of a crane. The segment 30 shown in FIG. 2 is provided with metal layers 4 on two longitudinal sides. The segment 31 shown in FIG. 3 has metal layers 4 on three longitudinal sides.
41 is provided. The segment 32 shown in FIG. 4 also has metal layers 4, 4 on four longitudinal sides.
2. These segments include:
A pawl 9 can be provided that projects into the refractory material. The segment 33 shown in FIG.
and a second metal layer 43 spot welded thereto. Segment 30 of the above embodiment,
31, 32, 33 may be placed in the housing of the structure in place of segment 3 of FIG. In structures utilizing the segments shown in Figures 2-4, the gas flows along the metal layers and plates, and in structures utilizing the segments of Figure 5, the gas flows between the mated metal layers. and flows along the metal layer. The segment 34 shown in FIG.
A flat metal layer 4 is provided on the opposite longitudinal surface. This segment 34 is 2
When assembled individually, gas passages are formed along the corrugated metal layer. Segment 35 shown in FIG. 7 corresponds to a combination of three segments 3 of FIG. A substantially U-shaped metal layer 45 is provided on this segment 35;
A pair of filler plates 10 are provided, which filler plates extend over the entire length of the segment 35 in the longitudinal direction and only a portion of the width in the width direction. Depending on the desired gas flow rate, the filling plate may be formed as a flat strip or as a strip with spacing elements such as ridges 11 as shown in FIG. In order to bond the stone and the filling plate 10 well, the filling plate 10 can also be provided with pawls 9. Seventh,
By configuring the filling plates 10 as shown in FIG. 8, gas flows between the filling plates, and also between the filling plates and the segments and along the metal layer. The structure 1 shown in FIG. 9 comprises a metal housing 2 surrounding a total of 12 segments arranged in 6 rows and 2 columns. Each segment has a desired cross-sectional shape in its longitudinal direction. That is, the segments 34a in the upper row have a groove-forming shape, and the segments 34 in the lower row have a wave-like shape. However, in reality, the segments in the two rows are both of the same shape. Place a plate between the two segments of each row. A plate having a desired cross-sectional shape may be used instead of this flat plate. A filler consisting of a pair of plates is placed between both rows. The structure 1 shown in FIG. 10 has four segments 3.
It comprises a metal housing 2 enclosing 5. These four segments are brought into contact with each other in the U-shaped metal layer 45 and with their unreinforced longitudinal sides against the inner surface of the housing, which for example consists of metal plates welded together. With this configuration, gas flows between the filling plates, and also between the filling plates and the segments and along the metal layer. For example, the material of the metal filler plate has a thickness of
A steel plate with a thickness of 0.5 to 3 mm is suitable, and one provided with a surface protective layer may also be used. The structure can be manufactured, for example, from a tar-bonded magnesium oxide material having the following composition and particle size distribution: Composition of sintered magnesium oxide MgO 96.2% by weight Fe ₂ O ₃ 0.2% by weight Al ₂ O ₃ 0.1% by weight CaO 2.5% by weight SiO ₂ 1.0% by weight Particle size distribution of sintered magnesium oxide 5-8 mm 20% by weight 3-5 mm 15% by weight 1-3mm 20% by weight 0.1-1mm 20% by weight 0-0.1mm 25% by weight 4% by weight of coal tarbitch is added as a binder to sintered magnesium oxide having the above composition and particle size distribution. Other tar, pitch, synthetic resin, etc. can also be used as the binding material. Other materials for producing stones that can be used for the structures according to the invention include those having the following composition and particle size distribution:

【table】

[Table] The above components are mixed to have a density of 1.22 g/cm ³ in order to chemically bond them using 3.7% by weight of Kieselite. The invention is not limited to the refractory materials mentioned above. Other refractory materials can also be used, such as mixtures of magnesium oxide and chromium ore or materials with a high content of aluminum oxide. The structure according to the invention has sufficient gas permeability. i.e. passages between each segment;
The passages between the inserts of the segments allow sufficient gas passage. The segments themselves are not practically gas-permeable, and therefore the refractory material used for the structure corresponds to the usual cladding materials for metal processing vessels. The breathable structure according to the invention is as stable as the surrounding sheathing, eliminating the need for frequent renewal of the structure. In the structure according to the invention, a metal plate is provided in the gas passage formed by the metal layer or plate on the surface and inside the segment, which metal plate prevents the ingress of metal, in particular pig iron, from the metal bath of the processing vessel. prevent. Due to their high viscosity, such metals have a particularly strong tendency to penetrate into gas passages. The above phenomenon will be further explained as follows. That is, by arranging the metal plate within the gas passage, a cooling effect can be produced, and heat can be quickly transferred to the cooling side of the structure. As a result, the invading treated metal moves only a short distance (several centimeters) before solidifying. However, if the metal plate is not provided, the processed metal will enter the gas passage and reach the cooling side end face.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an embodiment of the structure according to the present invention; FIGS. 2 to 7 are perspective views of each embodiment of the segment of the structure; FIG. 8 is a perspective view of an embodiment of the filling plate of the segment. 9 is a perspective view of a structure comprising the segments of FIG. 6; and FIG. 10 is a perspective view of a structure comprising the segments of FIG. 7. 1...Structure, 2...Housing, 31-3
5...Segment, 4,41-45...Metal layer,
7...End plate, 8...Connecting pipe, 10...Filled metal plate.

Claims (1)

Claims: 1. A ventilated refractory structure for use in insufflating a metal processing vessel through its cladding, comprising a passageway formed along the face of at least two elongated refractory segments (3). , the segments are spaced apart from each other by a thin metal layer to form a gas passageway between the segments along the metal layer, each of the segments having a first longitudinal surface, a second longitudinal surface, disposing the metal layer on a first longitudinal surface of at least one of the segments, the metal layer having a heated end face and a cooled end face;
a metal housing 2 surrounding said segments, connecting them to each other and in sealing abutment with a second longitudinal surface of said segments; a gas distribution chamber formed in said cooled end face of said segment; and said distribution chamber. 1. A fireproof structure comprising a connecting pipe 8 communicating with a fireproof structure and a means for supplying gas. 2. A fireproof structure according to claim 1, characterized in that the metal layer 4 is compression molded together with a fireproof material. 3. A fireproof structure according to claim 1, characterized in that a metal layer is disposed adjacent to a fireproof material. 4 Any one of claims 1 to 3
The refractory structure according to item 1, wherein the longitudinal surfaces of the segments and metal layers are formed as flat surfaces 4 or as flat surfaces 44 having a desired cross-sectional shape, such as grooved 34 or corrugated 34a. . 5 Any one of claims 1 to 4
The fireproof structure described in 2 is characterized in that another metal layer is provided on the metal layer 43 by, for example, welding, and no metal layer is interposed between mutually opposing longitudinal surfaces of adjacent segments. fireproof structure. 6 Any one of claims 1 to 5
In the fireproof structure described in
at least one pair of mutually adjacent metal plates 10 within the
A fireproof structure characterized in that the metal plates are buried therein, and a spacing member is arranged between these metal plates as necessary. 7. A refractory structure according to claim 1, further comprising a mortar layer between the second longitudinal surface of each segment and the metal housing.