Refractory lining structure and method of constructing refractory materials
The refractory lining structure addresses mechanical damage and construction inefficiencies by optimizing layering and angles in the refractory lining, enhancing durability and reducing costs in iron-making facilities.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- JFE STEEL CORP
- Filing Date
- 2025-11-14
- Publication Date
- 2026-07-23
Smart Images
Figure 2026121268000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a refractory lining structure and a method for constructing a refractory.
Background Art
[0002] A converter-type refining furnace usually has a plurality of refractory layers formed of at least a working refractory (wear refractory) and a permanent refractory inside an iron skin as a refractory structure. The damage factors of the refractories installed in iron-making facilities such as converter-type refining furnaces and ladles are roughly classified into chemical factors such as the reaction between the refractory and the slag, and mechanical factors such as structural, thermal or mechanical spalling. Among these, as one of the damages of the refractory due to mechanical factors, damage caused by stress (thermal stress) generated in the refractory is known. It is considered that such damage to the refractory can be suppressed by improving the stacking structure of the refractory, thereby relaxing the above-mentioned thermal stress.
[0003] For example, Patent Document 1 discloses that the damage of the refractory is improved by reverse-inclination stacking in which the furnace is constructed with an inclination opposite to the inclination of the throttle portion. Further, Patent Document 2 discloses that by expanding the reverse-inclination lining stacking of the converter refractory to the straight body portion and the lower corner portion, further reduction of the mechanical damage of the in-furnace refractory is achieved, and the long life and stable operation of the furnace become possible. Furthermore, Patent Document 3 discloses a lining structure in which an amorphous refractory is poured and constructed between the iron skin of the converter and the working brick, and a gap is provided between the working brick and the amorphous refractory.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Patent Document 2
Patent Document 3
[0005] However, in the methods described in Patent Documents 1 and 2, although stress reduction is achieved by the brick stacking structure with reverse inclination, slippage may occur in the bricks (formed refractories) in the reverse-inclined section, potentially causing bricks to fall out during operation. Furthermore, the interaction between this brick slippage and the stress generated in the axial direction of the furnace may cause so-called bending deformation in the refractories. For this reason, refractory stacking structures like those in Patent Documents 1 and 2 are not necessarily effective against damage to refractories due to mechanical factors.
[0006] Furthermore, while the method described in Patent Document 3 can absorb the collision of refractories due to the expansion of work bricks through gaps, it does not create a stacking structure that takes into account the relaxation of stress acting on individual work bricks or the durability of the bricks. In addition, pouring amorphous refractories into large containers such as converters requires the preparation of large cores and formwork appropriate to the container, which may increase construction costs.
[0007] Therefore, the present invention has been made in view of the above-mentioned problems, and aims to provide a refractory lining structure for a container and a method for constructing refractory materials that can suppress mechanical damage to the refractory material in a container for containing molten iron and reduce the construction cost of the refractory material. [Means for solving the problem]
[0008] (1) According to one aspect of the present invention, a refractory lining structure for a container containing molten iron is provided, wherein the container comprises a side wall portion extending in one direction and a constricted portion formed continuously at one end of the side wall portion and extending at an inclination angle α(°) toward the inside of the container with respect to the one direction, the side wall portion and the constricted portion having, in order from the inside of the container, a workpiece refractory, a permanent refractory, and a steel shell, the workpiece refractory is formed of a plurality of shaped refractory materials, and in a cross-sectional view parallel to the thickness direction of the steel shell in the side wall portion and the extending direction of the steel shell, the connecting portion where the side wall portion and the constricted portion connect is formed of n stages of the shaped refractory material satisfying 3≦n≦6, the thickness of the shaped refractory material of the connecting portion increases from the inside to the outside of the container in the cross-sectional view, and the opening angle β(°), which is the angle between two faces facing each other in the direction of the thickness, satisfies equation (1), thus providing a refractory lining structure.
[0009]
number
[0010] (2) In the refractory lining structure of the container described in (1) above, the workpiece refractory material is such that the step difference between adjacent shaped refractory materials on the inner surface of the container is 90 mm or less.
[0011] (3) In the refractory lining structure of the container described in (1) or (2) above, the workpiece refractory material is the compressive strength σ of the shaped refractory material. c (GPa), thermal expansion coefficient α h (K -1 ), the Poisson's ratio ν and the modulus of elasticity E, as well as the temperature difference ΔT(K) between room temperature and the internal temperature of the above container, satisfy equation (2).
[0012]
number
[0013] (4) In the refractory lining structure of any one of the containers described in (1) to (3) above, the container is a converter-type refining furnace.
[0014] (5) According to one aspect of the present invention, there is provided a method for constructing a refractory of a container for containing molten iron, wherein the container includes a side wall portion extending in one direction and a throttle portion continuously formed at one end of the side wall portion and extending obliquely at an inclination angle α (°) toward the inside of the container with respect to the one direction. The side wall portion and the throttle portion have a working refractory, a permanent refractory, and an iron skin in this order from the inside of the container. When constructing the working refractory at a connection portion where the side wall portion and the throttle portion are connected, in a cross-sectional view parallel to the thickness direction and the extending direction of the iron skin in the side wall portion, n shaped refractories satisfying 3 ≤ n ≤ 6 are stacked, and as the shaped refractory of the connection portion, in the cross-sectional view, the thickness increases from the inside to the outside of the container, and an opening angle β (°), which is an angle formed by two surfaces facing each other in the thickness direction, satisfies the formula (1). A method for constructing a refractory is provided.
[0015]
Number
Advantages of the Invention
[0016] According to one aspect of the present invention, there is provided a refractory lining structure of a container and a method for constructing a refractory, which can suppress mechanical damage to the refractory and reduce the construction cost of the refractory in a container for containing molten iron.
Brief Description of the Drawings
[0017] [Figure 1] It is a cross-sectional view showing the configuration of a container according to an embodiment of the present invention. [Figure 2] It is a partial cross-sectional view showing the configuration around the connection portion. <00 extraordinariness of the present invention. It is a cross-sectional view showing the configuration of the connection portion refractory. [Figure 4] It is a diagram showing the result of thermal stress calculation in the lining structure of a converter. <0000 extraordinariness of the present invention." [Figure 5] It is a graph showing the transition of the brick elastic modulus when repeated compressive stress is applied. [Figure 6] This is a schematic diagram showing the structure of the refractory material at the connection point in the examples, where (A) represents Example 1 of the present invention, (B) represents Example 2 of the present invention, (C) represents Example 3 of the present invention, (D) represents Example 4 of the present invention, and (E) represents Comparative Examples 1 and 2. [Figure 7] This is an explanatory diagram showing the shape of the refractory material in the constricted portion in the examples, where (A) shows the stepless shape in Examples 1 to 7 of the present invention and Comparative Example 1, and (B) shows the stepped shape in Comparative Example 2. [Modes for carrying out the invention]
[0018] The following detailed description will illustrate embodiments of the present invention with reference to the drawings. In the drawings, identical or similar parts are denoted by the same or similar reference numerals, and redundant descriptions are omitted. Each drawing is schematic and may differ from reality. Furthermore, the embodiments shown below are illustrative of apparatus and methods for realizing the technical idea of the present invention, and the technical idea of the present invention is not limited to the materials, structure, arrangement, etc., of the components described below. The technical idea of the present invention can be modified in various ways within the technical scope defined by the claims described in the patent claims.
[0019] <Refractory lining structure of containers> Referring to the drawings, a refractory lining structure for a container according to one embodiment of the present invention will be described. The container in the present invention is a large iron-making container for containing molten iron. In this embodiment, as an example, the container is a converter-type smelting furnace. As shown in Figure 1, the container 1 comprises a side wall portion 11, a constricted portion 12, and a bottom portion 13. In Figure 1, the X-axis direction is horizontal, and the Y-axis direction is vertical. Furthermore, in the following description, the container 1, which is a converter-type smelting furnace, is assumed to be in an upright state with the furnace opening facing upwards.
[0020] The side wall portion 11 is a cylindrical part extending in the Y-axis direction, and in a converter-type smelting furnace, it is also called the straight cylinder portion. The constricted portion 12 is formed continuously from the upper end of the side wall portion 11 and extends inclined toward the inside of the container 1 with respect to the extension direction of the side wall portion 11 (Y-axis direction). As shown in Figure 2, in an XY cross-sectional view, the angle of inclination toward the inside of the container 1 in the extension direction of the constricted portion 12 with respect to the extension direction of the side wall portion 11 is called the inclination angle α (°). The inclination angle α is about 30° when the container 1 is a converter-type smelting furnace, and is usually in the range of 10° to 45°. An opening (furnace mouth) is also provided on the upper end side of the constricted portion 12. The bottom portion 13 is the bottom of the container 1 formed continuously from the lower end of the side wall portion 11, and in a converter-type smelting furnace, it is also called the furnace bottom portion. Furthermore, in the container 1, the portion where the side wall portion 11 and the constricted portion 12 are connected, and the portion that is bent in an XY cross-sectional view, is also called the connecting portion 14. In this embodiment, the connecting portion 14 is the portion on the lower end side of the constricted portion 12, and is the portion where the inner surface (the inner surface of the workpiece refractory material 4, which will be described later) bends inward.
[0021] Furthermore, the container 1 is provided with a steel shell 2, a permanent refractory material 3, and a workpiece refractory material 4 in order from the outside to the inside. In other words, the container 1 has a multi-layer refractory structure in which at least the permanent refractory material 3 and the workpiece refractory material 4 are provided in order inside the steel shell 2.
[0022] As shown in Figure 2, the permanent refractory material 3 is composed of shaped refractory materials (bricks) made of MgO-C bricks, and is formed by stacking multiple shaped refractory materials in the Y-axis direction from the bottom 13 to the constricted section 12 inside the steel shell 2. The material and dimensions of the permanent refractory material 3 are appropriately set according to the conditions required depending on the dimensions and intended use of the container 1.
[0023] The workpiece refractory 4 is composed of shaped refractories made of MgO-C bricks, and is formed by stacking multiple shaped refractories inside the permanent refractory 3 from the bottom 13 to the constricted section 12. In this embodiment, in the workpiece refractory 4, the shaped refractories provided on the side wall section 11 are called side wall refractories 41, the shaped refractories provided on the constricted section 12 excluding the connecting section 14 are called constricted section refractories 42, and the shaped refractories provided on the connecting section 14 are called connecting section refractories 43.
[0024] The side wall refractory material 41 has a rectangular shape extending in the X-axis direction in an XY cross-sectional view. Furthermore, the thickness of the side wall refractory material 41 is constant, which is the length in the direction perpendicular to the extension direction. The workpiece refractory material 4 in the side wall section 11, excluding the connecting portion 14, is formed by stacking multiple side wall refractory materials 41 along the permanent refractory material 3 and steel shell 2 of the side wall section 11 in the Y-axis direction. In this embodiment, bricklaying in which the extension direction of the side wall refractory material 41 is perpendicular to the steel shell 2 is called vertical bricklaying.
[0025] As shown in Figures 2 and 3, the workpiece refractory material 4 of the connection section 14 is composed of n layers of connection section refractory material 43 satisfying 3 ≤ n ≤ 6 in an XY cross-sectional view. In an XY cross-sectional view, the connection section refractory material 43 extends from the inside to the outside of the container 1, and its thickness, which is the length in the direction perpendicular to the extension direction, increases from the inside to the outside of the container 1. In other words, the connection section refractory material 43 has a roughly trapezoidal or fan-shaped form that widens from the inside to the outside of the container 1. In addition, in an XY cross-sectional view, the connection section refractory material 43 only needs to have a straight line between its upper and lower surfaces, which are opposite surfaces in the thickness direction. Furthermore, the opening angle β(°) of the connection section refractory material 43, which is the angle between the upper and lower surfaces, which are two opposite surfaces in the thickness direction, satisfies equation (1). The workpiece refractory material 4 in the connection section 14 is formed by stacking n layers of connection section refractory material 43 in the positive Y-axis direction, inclined toward the inside of the container 1 (negative X-axis direction side).
[0026]
number
[0027] Furthermore, in this embodiment, the refractory material of the connecting portion 43 is formed such that, in an XY cross-sectional view, the end face (inner surface) on the inside of the container 1 (negative X-axis side in Figures 2 and 3) is a straight line substantially perpendicular to the extension direction of the connecting portion refractory material 43. In other words, the inner surface of the connecting portion refractory material 43 is formed such that the change in the inclination angle of the inner surface between the connecting portion refractory material 43 and the shaped refractory material (side wall refractory material 41, constricted portion refractory material 42, or connecting portion refractory material 43) of the workpiece refractory material 4 adjacent to it above and below is smaller than the inclination angle α. It is preferable that this change in inclination angle be 1 / 3 or less of the inclination angle α. In an XY cross-sectional view, the end face of the connecting portion refractory material 43 on the outside of the container 1 (positive X-axis side in Figures 2 and 3) has a shape that conforms to the inner surface of the permanent refractory material 3. If the thickness of the refractory material 43 in the XY cross-section, which is the length in the direction perpendicular to the extension direction of the inner surface, is too thin, it becomes difficult to manufacture the refractory material 43, potentially increasing manufacturing costs. For this reason, it is preferable that the thickness of the inner surface of the refractory material 43 in the XY cross-section be at least 1 / 6 of the thickness of the refractory material 41 on the sidewall. On the other hand, if the thickness of the inner surface of the refractory material 43 is too thick, corners will form, causing edge loading and leading to cracking (damage). For this reason, it is preferable that the thickness of the inner surface of the refractory material 43 in the XY cross-section be at least 1 / 3 of the thickness of the refractory material 41 on the sidewall.
[0028] The refractory material 42 in the constricted section has a roughly rectangular shape that extends from the inside to the outside of the container 1 in an XY cross-sectional view. The direction of extension of the refractory material 42 in the constricted section may be inclined with respect to the thickness direction of the steel shell 2, as shown in Figure 2, or it may be perpendicular to the steel shell 2. In addition, the thickness of the refractory material 42 in the constricted section is constant in an XY cross-sectional view, which is the length in the direction perpendicular to the extension direction. The workpiece refractory material 4 in the constricted section 12, excluding the connecting section 14, is formed by stacking multiple refractory materials 42 along the permanent refractory material 3 and steel shell 2 of the constricted section 12. The direction in which the refractory materials 42 are stacked is not particularly limited and may be in the vertical direction (Y-axis direction), or it may be inclined in the Y-axis direction, as shown in Figure 2. As shown in Figure 2, bricklaying in which the direction of extension of the refractory material 42 inclined with respect to the thickness direction of the steel shell 2 is called inclined bricklaying.
[0029] The stacking direction, shape, and dimensions of the pre-formed refractories constituting the workpiece refractory 4 at the bottom 13 are set appropriately using conventional technology. Furthermore, the permanent refractory 3 and the workpiece refractory 4 are formed by joining adjacent pre-formed refractories with unformed refractories.
[0030] Furthermore, it is preferable that there are no steps between adjacent refractories on the inner surface of container 1. Adjacent refractories are those adjacent in the vertical (Y-axis direction) and horizontal directions, respectively. If there are steps between adjacent refractories in the vertical direction, the protruding surface of the refractories that protrude into the furnace is directly exposed to high temperatures. Due to this step, the portion protruding into the furnace (the protruding part) becomes hotter than the surrounding area, and the increased thermal expansion leads to increased thermal stress. Repeated temperature changes during operation make the protruding part prone to delamination, which shortens the lifespan of the refractories. Moreover, in refractories with steps, localized stress concentration occurs at the protruding part. Repeated expansion and contraction due to temperature changes during operation makes it easy for cracks to develop at this stress concentration point, and damage progresses. Similarly, if there are steps between adjacent refractories in the horizontal direction, localized stress concentration occurs at the protruding part, and damage progresses. In this embodiment, the absence of a step between adjacent refractory materials means that the step between adjacent refractory materials is 90 mm or less. By keeping the step between adjacent refractory materials at 90 mm or less, it is possible to ensure the construction accuracy of the refractory materials while sufficiently reducing the progression of delamination and damage due to localized thermal stress and stress concentration.
[0031] Furthermore, the compressive strength σ of the standard refractories constituting the workpiece refractory 4 is c (GPa), thermal expansion coefficient α h (K -1 Preferably, the Poisson's ratio ν and the modulus of elasticity E (GPa), as well as the temperature difference ΔT (K) between room temperature and the internal temperature of container 1, satisfy equation (2). Room temperature is the temperature outside container 1.
[0032]
number
[0033] In the steelmaking process using container 1, which is a converter-type refining furnace, as the converter, a series of processes including molten iron charging, blowing, and tapping are repeatedly performed in container 1. Consequently, heat is repeatedly generated due to the decarburization reaction, and heat is released through sensible heat from the exhaust gas and heat dissipation from the steel shell 2. Of this, the heat released to the outside from the steel shell 2 is thought to be released from inside container 1 (inside the furnace) through the workpiece refractory 4 and permanent refractory 3. At this time, since the workpiece refractory 4 and permanent refractory 3 have thermal conductivity corresponding to their respective properties, a temperature gradient is created from inside the furnace to the steel shell 2. As a result, thermal stress is thought to be generated within the refractory material according to this temperature gradient. Therefore, it is important to devise a refractory structure (brickwork structure) that can accommodate the thermal stress generated in the workpiece refractory 4 of container 1.
[0034] In response, the inventors performed thermal stress calculations for the lining structure of a converter using MgO-C bricks as the work bricks. A portion of the refractory lining structure and the calculation results are shown in Figure 4. In Figure 4, reference numeral 2a denotes the steel shell, reference numeral 3a denotes the permanent refractory, and reference numeral 4a denotes the work refractory. In the thermal stress calculation, the work refractory 4a was stacked vertically with its end faces positioned approximately perpendicular to the steel shell 2a. Furthermore, in the thermal stress calculation, the physical properties of the work refractory 4a, permanent refractory 3a, joints, and steel shell 2a were calculated assuming the values in Table 1 to be in a steady state. The joint is the joint between adjacent monolithic refractory pieces of work refractory 4a and permanent refractory 3a, and is composed of monolithic refractory.
[0035] [Table 1]
[0036] As shown in Figure 4, the stress calculations revealed that among the thermal stresses generated within the refractory workpiece 4a, the stress values were locally excessive at the corners where the boundary between the side wall and the constricted section occurs (indicated by the arrows). In such areas, cracks will develop and propagate. Furthermore, these areas correspond to corners in brickwork. Therefore, by smoothing these corners, that is, by reducing the angle of the corners, the stress (edge load) generated at the corners can be reduced, and damage to the edges of the refractory can be prevented.
[0037] The inventors then examined these results in detail and discovered the present invention as a means to realize a smooth refractory lining structure. Specifically, in this embodiment, as described above, the workpiece refractory 4 of the connecting portion 14 extending from the side wall portion 11 to the constricted portion 12 is composed of n stages of connecting portion refractory 43 satisfying 3 ≤ n ≤ 6. In addition, the opening angle β of the connecting portion refractory 43 satisfies equation (1). In this way, in an XY cross-sectional view, the change in the inclination angle of the inner surface of adjacent standard-shaped refractory materials at the bent corner of the inner surface of the workpiece refractory 4 can be made smaller than the inclination angle α, resulting in a smoother corner and thus reducing edge load. If the connecting portion refractory 43 has 7 or more stages, the thickness of the connecting portion refractory 43 becomes thinner, making it difficult to manufacture the refractory and potentially increasing manufacturing costs. On the other hand, if the connecting portion refractory 43 has 2 or fewer stages, edge load occurs, which is undesirable. Furthermore, by setting the opening angle β to satisfy equation (1), the refractory material 43 at the connection point can be made into a shape that is less prone to edge loading. It is more preferable that the opening angle β be α / n.
[0038] Furthermore, when container 1 is used, for example, as a converter in a converter-type refining furnace, a series of processes including molten iron charging, smelting, and tapping are repeatedly performed. During this process, heat is repeatedly generated due to the decarburization reaction, and heat is repeatedly released through sensible heat from the exhaust gas and heat dissipation from the steel shell. This repeated exchange of heat generates periodic thermal stress in the refractory material. It is known that this repeated fluctuation in thermal stress causes cracks to form and propagate within the refractory material, eventually leading to its failure.
[0039] Therefore, the inventors investigated the failure of refractories for steelmaking when subjected to long-term periodic stress. Figure 5 shows the change in the elastic modulus of an alumina brick when repeated compressive stress is applied. It was confirmed that the elastic modulus of the refractory material decreases with repeated stress. Furthermore, the decrease in the elastic modulus decreased as the ratio of repeated stress to compressive strength (repeated load) decreased. After examining the conventional knowledge and these experimental results, the inventors found that failure due to repeated loading is reduced by using a refractory material that satisfies equation (2) as the standard-shaped refractory material for the workpiece refractory material 4. In other words, in addition to the conditions such as the shape of the connecting refractory material 43 described above, satisfying equation (2) can further prevent damage to the ends of the refractory material.
[0040] Furthermore, according to the refractory lining structure of this embodiment, since the workpiece refractory material 4 is a fixed-shape refractory material, unlike in the case of undefined-shape refractory materials, there is no need to use large cores or formwork when constructing the workpiece refractory material 4. Therefore, construction costs can be reduced.
[0041] <Variation> Although the present invention has been described above with reference to specific embodiments, this description is not intended to limit the invention. By referring to the description of the present invention, those skilled in the art will also see other embodiments of the invention, including various modifications, in addition to the disclosed embodiments. Accordingly, the embodiments of the invention described in the claims should be understood to include embodiments that include these modifications described herein, either individually or in combination.
[0042] For example, in the above embodiment, the container 1 was assumed to be a converter-type smelting furnace such as a converter, but the present invention is not limited to such examples. The container 1 may be any container for holding molten iron used under conditions in which thermal stress fluctuations of the steelmaking process are repeatedly applied, and may not be a converter-type smelting furnace. For example, the container 1 may be a molten iron ladle or a molten iron wheel. In the case of a molten iron wheel, the side wall portion 11 becomes the mirror portion and the constricted portion 12 becomes the conical portion. Furthermore, the material of the refractory material used can be appropriately selected depending on the type of container 1.
[0043] Furthermore, the method of bricklaying the refractory material 41 for the side walls and the refractory material 42 for the constricted section is not limited to the above embodiment. Various bricklaying methods such as vertical, inclined, and horizontal bricklaying can be applied to the refractory material 41 for the side walls and the refractory material 42 for the constricted section. Horizontal bricklaying is a bricklaying method in which the longitudinal direction of the standard-shaped refractory material is parallel to the steel shell.
[0044] Furthermore, in the above embodiment, the connecting portion 14 is the end of the constricted portion 12 based on the shape of the steel shell 2, but the present invention is not limited to this example. The connecting portion 14 is a bent portion on the inner surface of the workpiece refractory material 4. When the bent portion on the inner surface of the workpiece refractory material 4 is formed on the negative Y-axis side than the connecting portion 14 in Figure 1, the connecting portion 14 may include both the positive Y-axis side end of the workpiece refractory material 4 in the side wall portion 11 and the negative Y-axis side end of the workpiece refractory material 4 in the constricted portion 12.
[0045] Furthermore, the present invention can also be applied to a method for constructing refractory materials in a container 1. In this case, a method for constructing the connection portion 14 is specified, and conventional methods can be used for constructing other parts. When constructing the workpiece refractory material 4 at the connection portion 14, the same connection portion refractory material 43 as in the above embodiment is used, and the construction is carried out by stacking n layers of standard-shaped refractory material at the connection portion 14.
[0046] Furthermore, although the Y-axis direction was described as the vertical direction and the X-axis direction as the horizontal direction in the above embodiment, the present invention is not limited to such examples. In the present invention, the X-axis direction and the Y-axis direction are mutually orthogonal directions, and the X-axis direction is the thickness direction of the steel shell 2 in the side wall portion 11 (i.e., the stacking direction of the workpiece refractory 4, permanent refractory 3, and steel shell 2), and the Y-axis direction is the extension direction of the steel shell 2 in the side wall portion 11. [Examples]
[0047] The present inventors will now describe an example they have carried out. In the example, the container 1 was a converter-type refining furnace, and the refractory lining structure according to the above embodiment was used. The converter was capable of holding 350 tons of molten iron, and the workpiece refractory 4, other than the connecting refractory 43, was the same as in Figure 2. That is, the side wall refractory 41 was stacked vertically, and the constricted refractory 42 was stacked at an angle. The workpiece refractory 4 was an MgO-C refractory, and the value γ calculated by equation (3) was such that it satisfied the following conditions. In addition, the inclination angle α of the container 1 was set to 30°. In the example, the furnace life was investigated for a total of 7 conditions: 5 conditions in Examples 1 to 5 of the present invention in which the connecting refractory 43 was the same as in the above embodiment, and 2 conditions in Comparative Examples 1 to 2 in which the connecting refractory 43 was different from that of the above embodiment. Details of each condition are as follows.
[0048]
number
[0049] Example 1 of the present invention: As shown in Figure 6(A), the connecting portion 14 is made of six connecting portion refractory materials 43, and the opening angle β of each is set to 5°. γ = 0.78. As shown in Figure 7(A), the refractory material 42 of the throttling portion is shaped so that there is no step difference between adjacent refractory material 42 above and below. Invention Example 2: As shown in Figure 6(B), the connecting portion 14 is made of three-tiered connecting portion refractory material 43, with each opening angle β set to 10°. γ = 0.65. The throttling portion refractory material 42 is shaped so that there is no step difference between adjacent throttling portion refractory material 42 vertically, as shown in Figure 7(A). Invention Example 3: As shown in Figure 6(C), the connecting portion 14 is made of five connecting portion refractory materials 43, and the opening angle β of each is set to 6°. γ = 0.68. As shown in Figure 7(A), the refractory material 42 of the throttling portion is shaped so that there is no step difference between adjacent refractory material 42 above and below. Invention Example 4: As shown in Figure 6(D), the connecting portion 14 is opened and made into four stages of connecting portion refractory material 43 with different angles β, and the opening angles β1, β2, β3, and β4 are 7.5°, 6.5°, 9°, and 7°, respectively. γ = 0.66. The throttling portion refractory material 42 is shaped so that there is no step difference between adjacent throttling portion refractory material 42 vertically, as shown in Figure 7(A). Comparative Example 1: As shown in Figure 6(E), the connection part 14 was made of two-stage refractory material 43, with an opening angle β of 15° for each. γ = 0.65. The refractory material 42 of the throttling section was made to have no step difference between adjacent refractory materials 42 above and below, as shown in Figure 7(A). Comparative Example 2: As shown in Figure 6(F), the connection part 14 was made of two-stage refractory material 43, with an opening angle β of 15° for each. γ = 0.71. The refractory material 42 of the throttling section was made with a stepped shape between adjacent refractory materials 42 above and below, as shown in Figure 7(B).
[0050] Then, in the inventive example and comparative example container 1 (converter), decarburization operation was performed for a certain period, and the furnace life of each was evaluated. Furnace life was evaluated by measuring the remaining brick thickness using remote, non-contact measurement with a laser profile meter, and the number of times the measured remaining brick thickness fell below a predetermined thickness at which continued operation was a concern was defined as the furnace life.
[0051] Table 2 shows the evaluation results for the examples. In Invention Examples 1 to 5, where the connecting refractory material 43 was arranged in 3 to 6 layers, it was confirmed that the furnace life was significantly longer compared to Comparative Examples 1 to 2, where it was arranged in 2 layers. Furthermore, considering the material degradation due to repeated heat loads, it was confirmed that Invention Examples 2 to 4, which satisfy the conditions of equation (2), had a longer furnace life than Invention Example 1, which does not satisfy the conditions of equation (2). In addition, comparing Comparative Example 1 and Comparative Example 2, it was confirmed that Comparative Example 1, which does not have steps on the inner surface of the workpiece refractory material 4, had a longer furnace life. From the above, the superiority of the present invention was confirmed.
[0052] [Table 2] [Explanation of symbols]
[0053] 1 container 11 Side wall section 12 Aperture section 13 Bottom 14 Connection part 2,2a Ironhide 3,3a Permanent refractory 4,4a Workpiece refractory 41 Side wall refractories 42 Refractory material for the constricted section 43 Refractory material for connection
Claims
1. A refractory lining structure for a container that holds molten iron, The container comprises a side wall portion extending in one direction, and a constricted portion formed continuously with one end of the side wall portion and extending at an inclination angle α (°) toward the inside of the container with respect to the one direction. The side wall portion and the constricted portion have, in order from the inside of the container, a workpiece refractory, a permanent refractory, and a steel shell. The aforementioned workpiece refractory is formed of a plurality of shaped refractory materials, and in a cross-sectional view parallel to the thickness direction of the steel shell and the extension direction of the steel shell in the side wall portion, the connecting portion where the side wall portion and the constricted portion are connected is formed of n stages of the shaped refractory material satisfying 3 ≤ n ≤ 6. The refractory material of the connecting portion has a refractory lining structure in which, in the cross-sectional view, the thickness increases from the inside to the outside of the container, and the opening angle β (°), which is the angle between two opposing surfaces in the direction of the thickness, satisfies equation (1). [Math 1]
2. The refractory lining structure according to claim 1, wherein the difference in height between adjacent refractory pieces on the inner surface of the container is 90 mm or less.
3. The aforementioned workpiece refractory material has a compressive strength σ of the aforementioned shaped refractory material. ｃ (GPa), thermal expansion coefficient α ｈ (K －１ The refractory lining structure according to claim 1 or 2, wherein the Poisson's ratio ν and the modulus of elasticity E (GPa), and the temperature difference ΔT (K) between room temperature and the internal temperature of the container satisfy equation (2). [Math 2]
4. The refractory lining structure according to claim 1 or 2, wherein the container is a converter-type refining furnace.
5. A method for constructing refractories for a container that holds molten iron, The container comprises a side wall portion extending in one direction, and a constricted portion formed continuously with one end of the side wall portion and extending at an inclination angle α (°) toward the inside of the container with respect to the one direction. The side wall portion and the constricted portion have, in order from the inside of the container, a workpiece refractory, a permanent refractory, and a steel shell. When constructing the workpiece refractory material at the connection portion where the side wall portion and the constricted portion are connected, n layers of standard-shaped refractory material satisfying 3 ≤ n ≤ 6 are stacked in a cross-sectional view parallel to the thickness direction of the steel shell and the extension direction of the steel shell in the side wall portion. A method for constructing a refractory material, wherein, as the standard-shaped refractory material for the connection portion, in the cross-sectional view, the thickness increases from the inside to the outside of the container, and the opening angle β (°), which is the angle between two opposing surfaces in the direction of the thickness, satisfies equation (1). [Math 3]