TWI727776B - Formation method of safety layer refractory material of main blast furnace main channel - Google Patents

Abstract

The present invention provides a method for forming a refractory material for a safety layer of a blast furnace main passage, which includes: a heat-insulating brick installation step, which is tied to the bottom and wall of the iron shell of the blast furnace main passage and laying the heat-insulating bricks to form the heat insulation Brick bottom layer and insulating brick wall layer; the pouring material construction step is to pouring the pouring material on the aforementioned insulating brick bottom layer to form the pouring material bottom layer; wherein the composition of the pre-injected block and the pouring material includes: 50~ 90% by weight of Al ₂ O ₃ , 0 to 40% by weight of SiO ₂ and 0 to 10% by weight of SiC. With the method for forming the safety layer of the blast furnace sprue of the present invention, the safety of the molten iron leakage during milling of the blast furnace sprue can be improved, and the temperature of the iron shell during the pass milling of the blast furnace sprue can be reduced, thereby extending the blast furnace mainstream The service life of the iron shell.

Description

Formation method of safety layer refractory material of main flow channel of blast furnace

The invention relates to a method for forming a refractory material for the safety layer of the main passage of a blast furnace.

According to the theory, the steel industry is an industry that mainly produces various steel products. It is a basic industry built by the country and is called the mother of industry. However, because the steel industry needs to perform the production process of steel products at high temperatures, it is necessary to form a safety layer with fire-resistant properties in the main runner of the blast furnace used in the steel industry.

Therefore, some people have proposed a method for forming the refractory material of the safety layer of the sprue of a blast furnace, which is described below with reference to FIG. 1. Figure 1 is a longitudinal cross-sectional view of a blast furnace sprue showing the conventional method for forming a safety layer refractory material 90. Its main feature is that insulating bricks are laid on the bottom and walls of the blast furnace sprue iron shell 100 to form a partition. Heat brick bottom layer 2 and insulation brick wall layer 3, and then use the refractory brick bricklaying mode to form a U-shaped refractory brick layer 4 on the insulation brick bottom layer 2 and insulation brick wall layer 3, and in the U-shaped The upper side of the bottom of the refractory brick layer 4 is made of carbon bricks to form the carbon brick layer 5. The combination of the insulating brick bottom layer 2, the insulating brick wall layer 3, the refractory brick layer 4, and the carbon brick layer 5 is the conventional safety layer 90 of the blast furnace main channel. Finally, pouring material is poured into the sprue of the blast furnace where the safety layer 90 is formed to form the working layer 6, which is used in the process of producing steel products.

With the safety layer of this blast furnace main channel, the effect of protecting the blast furnace main channel iron shell and prolonging its service life is achieved.

However, the conventional security layer still has the following problems. For example, because the bricklaying mode will form many brick gaps between the bricks, when the blast furnace main runner is being overhauled and the work layer is removed with a strange handpiece, a large amount of vibration will be generated, causing looseness and damage between the refractory bricks. The brick gap is further increased and enlarged, which increases the risk of molten iron milling.

In addition, because of the high heat transfer value of carbon bricks (10W/mk~20W/mk), the temperature of the iron shell in the main channel of the blast furnace will often reach 350°C or more, or even close to 400°C, causing the iron shell to be heated and deformed. Therefore, in terms of the effect of prolonging the service life of the main iron shell of the blast furnace, the conventional safety layer still has room for improvement.

In view of this, the inventors of this case conducted research on the formation method of the safety layer refractory material of the blast furnace main channel, and invented a method of forming the safety layer refractory material of the blast furnace main channel (using pre-injected blocks). The injection block composition can greatly reduce the brick joints caused by the bricklaying mode, and can maintain the stability of the safety layer structure even when the working layer is removed, thereby improving the safety of the blast furnace main channel hot metal leaking milling, and can reduce the blast furnace The temperature of the iron shell when the main runner passes through milling.

The method for forming the refractory material for the safety layer of the blast furnace main channel of the present invention replaces the refractory brick layer formed by the bricklaying mode by assembling pre-injected blocks, and replaces the bricklaying mode with the base layer formed by the infusion material The carbon brick layer, as well as the use of pre-injected blocks and pouring materials with specific composition, can improve the safety of molten iron leakage during the use of the blast furnace sprue, and can reduce the temperature of the iron shell during the milling of the blast furnace sprue, thereby extending the blast furnace The service life of the main iron casing.

In order to achieve the above and other objectives, the present invention provides a method for forming a refractory material (using pre-injected blocks) for the safety layer of a blast furnace sprue, which includes: a heat-insulating brick laying step, which is attached to the iron shell of the blast furnace sprue Insulating bricks are laid on the bottom and walls of the base to form an insulating brick bottom layer and an insulating brick wall layer; the pouring material construction step is to pouring the pouring material on the aforementioned insulating brick bottom layer to form the pouring material bottom layer; The composition of the precast block and the pouring material includes: 50 to 90% by weight of Al ₂ O ₃ , 0 to 40% by weight of SiO ₂ and 0 to 10% by weight of SiC.

In one embodiment, it further comprises: a step of forming a self-flowing material layer, which is performed after the step of installing the pre-cast block, by pouring the self-flowing material between the insulating brick wall layer and the backing layer of the pre-cast block , To form a self-flowing material layer.

In an embodiment, a high-temperature fiber insulation board is further included between the main iron shell of the blast furnace, the bottom layer of the insulation brick and the wall layer of the insulation brick.

In one embodiment, the pre-injection block is arranged at the slag runner opening of the main runner iron shell of the blast furnace.

In one embodiment, the pre-injection block is disposed at the residual milling runner opening of the main runner iron shell of the blast furnace.

In an embodiment, the back of the pre-injection block further includes a positioning pad.

In an embodiment, the positioning pad is a trapezoidal bump.

In one embodiment, the thermal conductivity of the precast block at 500°C is 4.0 W/mK or less, and the compressive strength at 1450°C is greater than 80 MPa.

In one embodiment, the pre-cast block includes: 80 to 90% by weight of Al ₂ O ₃ , 0 to 15% by weight of SiO ₂ and 0 to 10% by weight of SiC.

In one embodiment, in the longitudinal section of the main runner of the blast furnace, the height ratio of the bottom layer of the pouring material to the backing layer of the pre-injected block is 1:5 to 1:6.

In summary, the method for forming the refractory material (using pre-injected blocks) for the safety layer of the blast furnace sprue of the present invention replaces the refractory brick layer formed by using the bricklaying mode with the assembled pre-injected block, and uses the cast material to form the refractory layer. The formation of the bottom layer of pouring material to replace the carbon brick layer formed by the bricklaying mode, and the use of pre-filled blocks and pouring materials with a specific composition can improve the safety of molten iron leakage when using the main channel of the blast furnace, and can reduce the mainstream of the blast furnace The temperature of the iron shell during pass milling, thereby extending the service life of the main iron shell of the blast furnace.

2: Bottom of insulation brick

3: Insulation brick wall layer

4: Refractory brick layer

5: Carbon brick layer

6: Operating layer

9: Pre-injection block

10: Pouring material bottom layer

20: Pre-filled block backing layer

30: Artesian material layer

40: High temperature fiber insulation board

50: high alumina brick layer

90: Security layer

90A~90C: Security layer

91: positioning pad

100: blast furnace main duct iron shell

A~B: height

C~D: thickness

[Figure 1] is a longitudinal cross-sectional view of the sprue of a blast furnace showing the conventional method for forming a safety layer refractory.

[Figure 2] is a longitudinal cross-sectional view of a blast furnace sprue showing a method for forming a safety layer refractory (using a pre-cast block) according to an embodiment of the present invention.

[Figure 3] is a longitudinal cross-sectional view of a blast furnace sprue showing a method for forming a safety layer refractory material (using a pre-cast block) according to another embodiment of the present invention.

[Figure 4] is a longitudinal cross-sectional view of a blast furnace sprue showing a method for forming a safety layer refractory (using a pre-cast block) according to another embodiment of the present invention.

[Figure 5] (A) is a schematic diagram showing the pre-injection block style in an embodiment of the present invention; (B) is a schematic diagram showing the positioning pad of the pre-injection block.

In order to fully understand the purpose, features and effects of the present invention, the following specific embodiments are used in conjunction with the accompanying drawings to give a detailed description of the present invention. The description is as follows.

First, the method for forming the safety layer refractory (using pre-cast blocks) of the blast furnace sprue in an embodiment of the present invention will be described.

Please refer to FIG. 2. FIG. 2 is a longitudinal cross-sectional view of a blast furnace sprue in a method for forming a safety layer 90A according to an embodiment of the present invention. As shown in Figure 2, firstly, the heat-insulating brick laying step is performed, which is in a brick-laying mode, and heat-insulating bricks are laid on the bottom and walls of the main iron shell 100 of the blast furnace to form a bottom layer of heat-insulating bricks 2 and Insulation brick wall layer 3. Here, in terms of the thickness of the insulating brick bottom layer 2 and the insulating brick wall layer 3, it can be 60 to 70 cm, preferably 65 cm. Moreover, as for the material of the heat-insulating brick, conventional heat-insulating bricks, such as clay bricks, mullite heat-insulating bricks, diatomaceous earth bricks, etc., can be used.

Next, the pouring material construction step is carried out, which is by pouring the pouring material on the aforementioned insulating brick bottom layer 2 to form the pouring material bottom layer 10. Regarding the thickness A of the bottom layer 10 of the pouring material, it can be 160 to 180 cm, preferably 170 cm. In addition, in terms of the material of the potting material, its composition includes: 50 to 90% by weight of Al ₂ O ₃ , 0 to 40% by weight of SiO ₂ and 0 to 10% by weight of SiC. By using pouring materials and replacing the carbon bricks of the conventional bricklaying mode with the perfusion method, the brick joints caused by the bricklaying mode can be reduced and the safety of the hot metal leaking milling of the main channel of the blast furnace can be effectively improved.

Then, proceed to the pre-injection block installation step, which is to install the pre-injection block on the bottom layer 10 of the infusion material close to the insulating brick wall layer 3 and on the insulating brick wall layer 3 to form a pre-injection block back Lining 20. Here, "the position of the bottom layer of the pouring material close to the insulating brick wall" means that in the cross-sectional view of FIG. 2, the left and right sides of the bottom layer of the pouring material 10 are taken as the starting point, and the starting point is toward the center of the bottom layer of the pouring material 10 respectively. Move the range of 0~10% to 0~15% of the length of the bottom 10 of the pouring material. For example, if the total length of the pouring material bottom layer 10 in the cross-sectional view of FIG. 2 is 100 cm, then "the position of the pouring material bottom layer close to the insulating brick wall layer" refers to the direction from the left and right sides of the pouring material bottom layer 10 to each The center of the bottom layer 10 of the pouring material moves 0-10 cm to a range of 0-15 cm.

In the pre-injection block installation step, the conventional bricklaying mode is not used, but the pre-injection block is pre-injected in the form of a large block, and then the pre-injection block is installed in the safety layer of the main flow channel of the blast furnace. Compared with bricklaying mode, because pre-injected pre-injected blocks are used to assemble, it can reduce the large amount of manpower required in bricklaying mode, and when the main runner of the blast furnace is being overhauled, the working layer is removed. It can also reduce the increase of brick cracks when the bricks become loose due to vibration. As a result, the use of pre-cast blocks to replace conventional refractory bricks can reduce the brick joints caused by the bricklaying mode, and can effectively improve the safety of hot metal leak milling when the main runner of the blast furnace is used.

Furthermore, the thickness of the pre-cast block backing layer 20 (that is, the width of the pre-cast block) can be, for example, 150 to 200 cm. In addition, in terms of the material of the precast block, its composition includes: 50 to 90% by weight of Al ₂ O ₃ , 0 to 40% by weight of SiO ₂ and 0 to 10% by weight of SiC. In a preferred embodiment, the pre-injection block contains: 80 to 90% by weight of Al ₂ O ₃ , 0 to 15% by weight of SiO ₂ and 0 to 10% by weight of SiC.

The design of the above-mentioned pre-injected block material is based on aluminum oxide (Al ₂ O ₃ ) and _{silicon dioxide (SiO 2} ), and a small amount of silicon carbide (SiC) is added as the main design axis. In this way, the pre-cast block can exhibit high strength (for example, the compressive strength at 1450℃ is greater than 80MPa) and low heat transfer (for example, the thermal conductivity at 500℃ is below 4.0W/mK, or even below 3.5W/mK The characteristics of) make the pre-injected block not easy to be damaged due to collision during assembly and hanging operations, and achieve the purpose of effectively reducing the temperature of the iron shell of the main channel of the blast furnace.

Here, on the longitudinal section of the main runner iron shell 100 of the blast furnace, the height ratio of the bottom layer 10 of the pouring material to the backing layer 20 of the pre-injection block can be 1:5~1:6, that is, the ratio of the following A and B The ratio can be 1:5~1:6. For example, as shown in FIG. 2, the height A of the bottom layer of the pouring material 10 (also the thickness of the bottom layer of the pouring material in this figure) A can be 172 cm, and the height B of the backing layer 20 of the pre-cast block can be 970 cm. With the aforementioned height ratio, the temperature of the main duct iron shell of the blast furnace can be lowered more effectively.

Finally, after forming the safety layer 90A as described above (in Figure 2, the combination of the insulating brick bottom layer 2, the insulating brick wall layer 3, the pouring material bottom layer 10 and the pre-cast block backing layer 20), then The blast furnace main runner iron shell 100 on which the safety layer 90A is formed is filled with casting material to form the working layer 6. The working layer 6 covers the top of the safety layer 90A. Here, as for the working layer 6, it forms a U-shaped working layer, and the thickness of the bottom of the working layer is 260 cm, and the thickness of the left and right sides is 400 to 600 cm. As far as casting materials are concerned, low-cement casting materials or ultra-low cement casting materials made by adding high-alumina cement and debonding agent can be used; or they can be used without adding high-alumina cement, and silica gel is used to replace water during pouring construction. Made of cement-free castable material.

In a preferred embodiment, a self-flowing material layer can be formed between the insulating brick wall layer and the pre-cast block backing layer. The following is a description with reference to FIG. 3, which is a longitudinal cross-sectional view of a blast furnace sprue in a method for forming a safety layer according to another embodiment of the present invention. In FIG. 3, the layers that are the same as those in FIGS. 1 to 2 are denoted by the same symbols, and their description is omitted.

First, as shown in Fig. 3, in the same manner as Fig. 2, the insulating brick bottom layer 2, the insulating brick wall layer 3, the pouring material bottom layer 10, and the pre-cast block backing layer 20 are respectively formed; however, it is different from Fig. 2 However, in the embodiment of FIG. 3, the pre-cast block backing layer 20 is not close to the insulating brick wall layer 3, but is left between the insulating brick wall layer 3 and the pre-cast block backing layer 20 The gap, and the width of the aforementioned gap can be 50-60 cm.

Next, a self-flowing material is poured between the insulating brick wall layer 3 and the pre-injected block backing layer 20 to form a self-flowing material layer 30; in other words, the self-flowing material layer 30 is filled and formed in the aforementioned gap Inside. As far as the material of the artesian material layer 30 is concerned, it may be corundum, bauxite or aluminum cement. In addition, because the pre-cast block backing layer 20 is a pre-cast block formed in advance, if it is directly joined with the insulating brick wall layer 3, some gaps will inevitably occur during joining and there is a risk of loosening. Therefore, by forming the self-flowing material layer 30 between the insulating brick wall layer 3 and the pre-cast block backing layer 20, the insulating brick wall layer 3 and the pre-cast block backing layer 20 can be further closely adhered to each other. The effect of fixing the heat-insulating brick wall layer 3 and the pre-injected block backing layer 20 is achieved. Thus, in FIG. 3, the combination of the insulating brick bottom layer 2, the insulating brick wall layer 3, the pouring material bottom layer 10, the pre-cast block backing layer 20 and the artesian material layer 30 forms a more stable safety layer 90B, And more effectively reduce the temperature of the main runner iron shell of the blast furnace, and extend the life of the main runner of the blast furnace.

In a more preferred embodiment, a high-temperature fiber insulation board is further included between the main iron shell of the blast furnace and the bottom layer of the insulation brick and the wall layer of the insulation brick. And optionally, a high alumina brick layer can be used to cover the top of the pre-cast block backing layer and the self-flowing material layer. The following is a description with reference to FIG. 4, which is a longitudinal cross-sectional view of a blast furnace sprue in a method for forming a safety layer 90C according to another embodiment of the present invention. In FIG. 4, the same layers as those in FIGS. 1 to 3 are labeled with the same symbols, and their description is omitted.

First, as shown in Fig. 4, in the same manner as Fig. 3, the insulating brick bottom layer 2, the insulating brick wall layer 3, the pouring material bottom layer 10, the pre-cast block backing layer 20, and the artesian material layer 30 are respectively formed; However, unlike FIG. 3, in the embodiment of FIG. 4, between the main blast furnace iron shell 100 and the insulating brick bottom layer 2 and the insulating brick wall layer 3, a high-temperature fiber insulation board is also included. 40. Here, the material of the high-temperature fiber heat insulation board 40 may be alumina fiber, ceramic fiber, etc., but it is not limited thereto.

In addition, the thickness of the artesian material layer 30, that is, the width of the aforementioned gap, may be 50 to 60 cm. The thickness C of the insulating brick bottom layer 2 and the insulating brick wall layer 3 is the same as the aforementioned figure 2 and can be 60 to 70 cm. The thickness A of the bottom layer 10 of the pouring material is also the same as that of FIG. 2, and can be 170 to 180 cm. The thickness of the backing layer 20 of the pre-injection block is also the same as The above figure 2 is the same, it can be 150~200 cm. In addition, the thickness of the high-temperature fiber heat insulation board 40 is not particularly limited, and may be 0.3 to 0.9 cm, preferably 0.6 cm.

In addition, the high alumina brick layer 50 can be used to cover the top of the pre-cast block backing layer 20 and the artesian material layer 30 to fill the pre-cast block backing layer 20 and the self-flowing material layer 30 to the upper end of the blast furnace main runner iron shell 100 The height difference between the pressure plates. Here, the material of the high alumina brick layer 50 can be selected from corundum series high alumina bricks, alumite series high alumina bricks, etc., and is not limited thereto. In addition, the thickness D of the high alumina brick layer 50 may be 30 to 70 cm.

Thus, in FIG. 4, the safety layer 90C includes a bottom layer of insulating bricks 2, a wall layer of insulating bricks 3, a bottom layer of pouring material 10, a backing layer of pre-cast blocks 20, a layer of artesian materials 30, and a high-temperature fiber insulation board. 40 and 50 of high alumina brick layer. The high-temperature fiber insulation board 40 can further improve the thermal insulation effect of the safety layer 90C to protect the blast furnace main channel iron shell, and can more effectively reduce the temperature of the blast furnace main channel iron shell and prolong the life of the blast furnace main channel iron shell.

Finally, although the working layer 6 is not shown in FIGS. 3 to 4, as in FIG. 2, after the safety layer is formed as described above, the blast furnace main runner iron shell 100 on which the safety layer is formed is filled and poured材 to form a working layer 6. In addition, the thickness and material of the working layer 6 may be the same as those described in the description of FIG. 2 above.

In addition, the safety layers 90A to 90C shown in Figures 2 to 4 are distributed in various positions of the main iron shell of the blast furnace, and preferably are mainly distributed in the whole section of the main iron shell of the blast furnace. This is because the thermal stress in the front section of the main iron casing of the blast furnace is relatively strong, and more pre-cast blocks are required to disperse the thermal stress. In addition, the safety layer is also formed at the slag runner opening and/or the residual milling runner opening of the blast furnace main runner iron shell, that is, the pre-injection block is arranged at the slag runner opening and/or residual milling runner opening of the blast furnace main runner iron shell.

Next, in a preferred embodiment, the back of the pre-injection block further includes a positioning pad. The following is a description with reference to FIG. 5 together. FIG. 5A is a schematic diagram showing the style of the pre-injection block in an embodiment of the present invention; FIG. 5B is a schematic diagram showing the positioning pad of the pre-injection block.

First, as shown in FIG. 5A, the back of the pre-injection block 9 also includes a positioning pad 91. By including the positioning pad 91 on the back of the pre-injection block 9, the positioning of the hanging assembly of the pre-injection block 9 can be facilitated during construction, and the construction and assembly efficiency of the pre-injection block 9 can be effectively improved. Regarding the arrangement of the positioning pads 91, as shown in FIG. 5A, two positioning pads 91 can be designed symmetrically on the upper and lower ends of the back of the pre-injection block 9, respectively.

Next, as shown in FIG. 5B, the top surface of the positioning pad 91 is a trapezoid, and the positioning pad 91 is a trapezoidal protrusion. With the design of the trapezoidal convex block of the positioning pad 91, the construction and assembly efficiency of the pre-cast block 9 can be effectively improved.

In addition, the pre-injection block 9 is not limited to the style shown in FIG. 5, and can be designed differently according to the use position of the pre-injection block 9 (the front section of the main runner, the rear section, the slag runner or the residual milling runner, etc.). However, in the present invention, the pre-injection block 9 preferably includes a positioning pad 91.

Specific examples are listed below to describe the method for forming the safety layer refractory (using pre-cast blocks) of the blast furnace sprue of the present invention.

[Example]

First, use the method of the present invention to form a safety layer as shown in Figure 4, and the safety layer includes: insulation brick bottom layer, insulation brick wall layer, pouring material bottom layer, pre-injected block backing layer, self-flowing material layer, high-temperature fiber Insulation board and high alumina brick layer. Among them, the thickness of the insulating brick bottom layer and the insulating brick wall layer is 65 cm; the thickness of the pouring material bottom layer is 172 cm; the thickness of the backing layer of the pre-cast block is 200 cm; the thickness of the artesian material layer is 56 cm; high temperature The thickness of the fiber insulation board is 0.6 cm; the thickness of the high alumina brick layer is 68 cm.

Secondly, the casting material is filled in the iron shell of the main runner of the blast furnace to form a working layer. The operation layer covers the top of the safety layer. Here, it is preferable to form a U-shaped working layer, and the thickness of the bottom of the working layer is 260 cm, and the thickness on the left and right sides is 400 to 600 cm.

Among them, the material of the bottom layer of the insulation brick and the wall layer of the insulation brick are silica or bauxite. The bottom layer of the pouring material is made of M clinker, andalusite or aluminum cement. The material of the backing layer of the pre-injected block is Use corundum, bauxite or aluminum cement. The material of the high-temperature fiber insulation board is alumina fiber or ceramic fiber. The material of the artesian material layer is corundum, bauxite or aluminum cement. The material of the high alumina brick layer is steel jade or bauxite. The working layer is made of steel jade, silicon carbide or aluminum cement.

Next, 28 pre-injection blocks (safety layer) are used within 12 meters of the front section of the iron casing of the main blast furnace, and 5 pre-injection blocks (safety layer) are used within 5 meters of the back section. In addition, one pre-injection block (safety layer) is used at the entrance of the residual milling runner; two pre-injection blocks (safety layer) are used at the slag runner entrance. Next, measure the temperature of the iron shells at 16 locations of the main runner of the blast furnace (13 in the front section and 3 in the rear section).

The results of the above temperature measurement are shown in Table 1 below.

With reference to Table 1, it is calculated that the average temperature of the iron shell of the main runner of the blast furnace is 244°C. It can be seen from this that after using the safety layer of the present invention, the average temperature of the iron shell of the blast furnace main channel can be controlled within 300℃, which greatly improves the average temperature of the blast furnace main channel iron shell when the conventional brick cutting mode is used to reach 350 The temperature is above ℃, so the new construction method can effectively reduce the temperature of the main duct iron shell of the blast furnace by 60~100℃.

The present invention has been disclosed in a preferred embodiment above, but those skilled in the art should understand that the embodiment is only used to describe the present invention and should not be construed as limiting the scope of the present invention. It should be noted that all changes and substitutions equivalent to this embodiment should be included in the scope of the present invention. Therefore, the protection scope of the present invention should be defined by the scope of the patent application.

2: Bottom of insulation brick

3: Insulation brick wall layer

6: Operating layer

10: Pouring material bottom layer

20: Pre-filled block backing layer

90A: Security layer

100: blast furnace main duct iron shell

A~B: height

Claims (7)

A method for forming a refractory material for a safety layer of a blast furnace main channel, which includes: a heat-insulating brick installation step, which is tied to the bottom and walls of the iron shell of the blast furnace main channel and laying insulating bricks to form a bottom layer of the heat-insulating bricks and Insulation brick wall layer; the pouring material construction step, which is pouring the pouring material on the aforementioned insulating brick bottom layer to form the pouring material bottom layer; the pre-injecting block installation step, which is to install the pre pouring block on the bottom of the pouring material bottom layer A position close to the insulating brick wall layer and on the insulating brick wall layer to form a pre-cast block backing layer, and the back of the pre-cast block also includes a trapezoidal bump as a positioning pad; wherein, the pre-cast block The composition of the injection block and the pouring material includes: 50 to 90% by weight of Al ₂ O ₃ , 0 to 40% by weight of SiO ₂ and 0 to 10% by weight of SiC; and on the longitudinal section of the main runner iron shell of the blast furnace , The height ratio of the bottom layer of the pouring material to the backing layer of the pre-injected block is 1:5~1:6. The method for forming a refractory material for a safety layer of a blast furnace sprue as claimed in claim 1, further comprising: a step of forming a self-flowing material layer, which is performed by pouring the self-flowing material into the pre-injection block after the installation step. Between the insulating brick wall layer and the pre-injected block backing layer, a self-flowing material layer is formed. The method for forming a refractory material for a safety layer of a blast furnace sprue as described in claim 1, wherein, between the iron shell of the blast furnace sprue and the bottom layer of the insulating brick and the insulating brick wall layer, high-temperature fiber heat insulation is further included board. The method for forming a safety layer of a blast furnace main duct iron shell according to claim 1, wherein the pre-injected block is arranged at the slag runner opening of the blast furnace main duct iron shell. The method for forming a safety layer of a blast furnace main runner iron shell according to claim 1, wherein the pre-injected block is arranged at the residual milling runner opening of the blast furnace main runner iron shell. The method for forming a safety layer of a main duct iron case of a blast furnace according to any one of claims 1 to 5, wherein the thermal conductivity of the precast block at 500°C is 4.0W/mK or less, and at 1450°C The compressive strength is greater than 80MPa. The method for forming a safety layer of a main iron shell of a blast furnace according to any one of claims 1 to 5, wherein the pre-injected block contains: 80 to 90% by weight of Al ₂ O ₃ and 0 to 15% by weight SiO ₂ and 0-10% by weight of SiC.

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