Composite fiber reinforced refractory brick and preparation method thereof

Abstract

The invention relates to the field of fire resistance, in particular to a composite fiber reinforced refractory brick and a preparation method thereof.The composite fiber reinforced refractory brick is prepared from, by weight, 70-80 parts of mullite, 40-50 parts of quartz, 20-30 parts of alumina, 40-60 parts of magnesium aluminate spinel fine powder, 5-10 parts of silicon carbide powder, 1-5 parts of composite fibers and 0.5-1 part of sodium tetrapolyphosphate; wherein the composite fiber is composed of modified zirconium oxide fiber and magnesium metal fiber. According to the preparation method, zirconium oxide fiber dispersion liquid, hydroxyethyl methylacrylate and N, N-methylene acrylamide are subjected to cross-linking polymerization under the action of a silane coupling agent, an initiator and an emulsifier, macromolecular chains are loaded on the surfaces of zirconium oxide fibers, the macromolecular chains are taken as cross-linking points, the zirconium oxide fibers are mutually linked to form a cross-linked polymer, and the zirconium oxide fibers are uniformly dispersed in the cross-linked polymer. The two-dimensional zirconium oxide fibers are constructed into a three-dimensional network structure, and the modified zirconium oxide fibers are prepared. The composite fiber can significantly enhance the strength and mechanical toughness of the refractory brick.

Description

Technical Field

[0001] The present invention relates to the field of refractory, and in particular to a composite fiber reinforced refractory brick and a preparation method thereof. Background Art

[0002] Due to their ultra-high refractoriness (not less than 1580°C) and stable physical and chemical properties during the sintering process, refractory materials are used as structural materials for thermal equipment such as high-temperature kilns, as well as materials for industrial high-temperature containers and components, playing an indispensable role in national construction and development. There are many types of refractory materials available. Based on their mineral composition, they can be divided into silica, aluminum silicate, magnesia, dolomite, olivine, spinel, carbonaceous, zirconium-containing refractory materials, and special refractory materials; based on the heat treatment method, they can be divided into unfired products, fired products, and fused-cast products; based on the method, they can be divided into block products and amorphous refractory materials; based on their refractoriness, they can be divided into ordinary, high-grade, and special-grade refractory products; based on their chemical properties, they can be divided into acidic, neutral, and alkaline refractory materials; based on their density, they can be divided into lightweight and heavyweight refractory materials; based on their manufacturing method, they can be divided into natural ores and artificial products. Most refractory materials are manufactured from natural ores such as refractory clay, silica, magnesite, and dolomite. However, the use of certain industrial and synthetic raw materials, such as industrial alumina, silicon carbide, synthetic mullite, and synthetic spinel, is also increasing. Due to their simple production process, convenient construction, and long service life, they are used as lining materials for industrial furnaces that are subject to high thermal shock, strong mechanical impact, high temperature stability, and difficult construction.

[0003] The patented technology of "A high-strength refractory castable and its preparation method" (CN202210758855.5) introduces polyvinyl alcohol-modified polyurethane as a water reducer to prepare a high-strength refractory castable. However, its poor mechanical toughness will affect its thermal shock resistance at high temperatures. Due to the large temperature difference between rapid cooling and heating and the gap between use, the refractory material is very likely to crack and peel off under the action of thermal expansion and contraction, which affects the integrity of the refractory material and reduces the service life of the refractory material.

[0004] The patented technology of "Fiber-reinforced refractory castable and its preparation method" (CN202211452504.8) mainly describes the preparation method of fiber-reinforced refractory castable. However, adding a certain amount of metal aluminum fiber and / or magnesium-aluminum alloy fiber to the refractory castable cannot significantly improve the mechanical toughness. Poor mechanical toughness will greatly increase the damage rate of refractory products.

[0005] The patented technology of "Ceramic Fiber Refractory Castable and Preparation Method Thereof" (CN201910073196.X) prepares ceramic fiber refractory castable by introducing stainless steel fiber. However, stainless steel fiber is easily oxidized in a high temperature environment to form FeO, Fe2O3, Fe3O4, etc., which reduces the strength of the material and causes large volume expansion, destroying the material structure and affecting the structural stability of the refractory material. At the same time, iron oxide significantly reduces the refractoriness of the refractory material. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the present invention aims to provide a composite fiber reinforced refractory brick and a preparation method thereof, by introducing composite fibers, ultimately obtaining a refractory brick with high strength, strong mechanical toughness and long service life.

[0007] The specific technical solutions of the present invention are as follows:

[0008] In order to achieve the above-mentioned object, the present invention adopts the following technical scheme: a composite fiber reinforced refractory brick and a preparation method thereof, comprising the following components in parts by weight: 70-80 parts of mullite, 40-50 parts of quartz, 20-30 parts of alumina, 40-60 parts of magnesia alumina spinel fine powder, 5-10 parts of silicon carbide powder, 1-5 parts of composite fiber and 0.5-1 part of sodium tetrapolyphosphate.

[0009] The present invention utilizes mullite, quartz, and alumina as aggregates, magnesia-alumina spinel powder as a pulverulent material, silicon carbide powder as a sintering promoter, composite fiber as a binder, and sodium tetrapolyphosphate as a water reducer to produce refractory bricks with strong mechanical toughness and high strength. Mullite, an inorganic compound with a melting point exceeding 1850°C, along with quartz and alumina, forms a common, high-quality silicon-alumina oxide system for refractory bricks. The magnesium oxide and aluminum oxide in the magnesia-alumina spinel powder are also inorganic oxides with high melting points. They react with the silicon-alumina oxides to form a solid solution, enhancing the refractoriness of the refractory bricks.

[0010] Furthermore, the particle size of the aggregate is 0.088-10 mm, wherein the Al2O3 content of the mullite fine powder is ≥68wt%, the SiO2 content of the quartz is ≥92wt%, and the Al2O3 content of the alumina is ≥48wt%.

[0011] Furthermore, the particle size of the magnesia-alumina spinel fine powder is less than 0.088 mm, the Al2O3 content thereof is 71-85wt%, and the (Al2O3+MgO) content is 98wt%.

[0012] Furthermore, the particle size of the silicon carbide powder is less than 4 μm, wherein SiC ≥ 98 wt %.

[0013] Furthermore, the composite fiber is composed of modified zirconia fiber and magnesium metal fiber, wherein the modified zirconia fiber accounts for 80-88wt% and the balance is magnesium metal fiber; the diameter of the modified zirconia fiber is 0.02-0.1mm and the length is 0.5-1mm, and the diameter of the magnesium metal fiber is 0.2-1mm and the length is 3-6mm.

[0014] Magnesium is a metal material with excellent affinity, combining well with inorganic materials and resisting detachment or separation after being composited with inorganic materials. Furthermore, magnesium possesses ductility comparable to that of metallic iron, and its density is relatively low, similar to that of metallic aluminum. When added to refractory bricks, it enhances the fracture toughness of the bricks, allowing them to withstand greater fracture deformation without breaking. However, due to its melting point of 650 degrees Celsius, the toughening effect of magnesium deteriorates or even disappears when refractory bricks are used at high temperatures. Therefore, modified zirconia fibers with a higher failure temperature are added to compensate for the adverse effects of magnesium at high temperatures.

[0015] Zirconia has better mechanical toughness than silica-alumina systems, and adding zirconium oxide fibers to silica-alumina refractory bricks can enhance the brick's toughness. When tiny cracks appear within the brick, the embedded zirconium oxide fibers prevent further crack propagation, thereby enhancing the brick's toughness. To further enhance the mechanical toughness of zirconium oxide fibers, zirconium oxide is modified.

[0016] Furthermore, the preparation method of the modified zirconia fiber comprises the following steps:

[0017] SS1: Immerse the zirconia fiber in a 0.5% to 1% sodium carbonate solution for 4 to 6 hours, centrifuge the material, wash and vacuum dry it, and then mix it with a mixed solution of ethanol and purified water in a volume ratio of 3:1. Ultrasonic dispersion is performed to form a uniform dispersion. A silane coupling agent is then added. The temperature is then raised to 60 to 70°C, stirred for 4 to 8 hours, cooled, discharged, and the solid material is separated by centrifugation.

[0018] SS2: After the solid material is evenly dispersed in a mixed solution of ethanol and purified water in a volume ratio of 1:1, hydroxyethyl methacrylate, N,N-methylene acrylamide and initiator are added and stirred evenly. After stirring at 90-100°C for 12-16 hours, the solid material is separated to obtain a precursor;

[0019] SS3: Disperse the precursor in purified water, add emulsifier, mix evenly, continue to add cyclohexane and stir evenly to form a stable emulsion, stir and emulsify at 60-80°C for 20-30 minutes, then add initiator, after addition, raise the temperature to 70-80°C, stir for 6-8 hours, separate the material, wash and freeze-dry to obtain modified zirconia fiber.

[0020] Furthermore, in step SS1, the silane coupling agent is any one of propylene glycol methyl acrylate or 3-(methacryloyloxy)propyltrimethoxysilane.

[0021] Furthermore, in step SS2 and step SS3, the initiator is any one of vinyl nitrate or ethyl peroxypropionate.

[0022] Furthermore, in step SS3, the emulsifier is any one of sodium lauryl sulfonate or sodium lauryl phosphate.

[0023] In the above technical solution, a silane coupling agent is added to the treated zirconia fiber dispersion, and the unsaturated olefinic functional group in the silane coupling agent structure serves as an active initiation site. The initiator initiates cross-linking polymerization of hydroxyethyl methacrylate and N,N-methylene acrylamide, which then reacts with the active groups on the surface of the zirconia fiber, thereby loading a macromolecular chain on the surface of the zirconia fiber. Under the action of the Pickering emulsion, the macromolecular chain is fixed on the surface of the zirconia fiber. With the macromolecular chain as the cross-linking point, the zirconia fibers are interconnected to form a cross-linked polymer, and the two-dimensional zirconia fiber is constructed into a three-dimensional network structure to obtain a modified zirconia fiber.

[0024] A composite fiber reinforced refractory brick and a preparation method thereof, specifically comprising the following steps:

[0025] S1: Mix the aggregate and powder evenly, then add the binder and ball mill for 5-15 minutes to obtain ball-milled aggregate;

[0026] S2: adding a sintering agent and a water reducing agent to the ball-milled aggregate obtained in step S1, and ball-milling for 5 to 15 minutes to obtain a mixture;

[0027] S3: adding water to the mixture obtained in step S2, stirring evenly, pouring into a mold, shaking and compacting in layers, letting it stand, and demolding to obtain refractory brick blanks;

[0028] S4: sintering the refractory brick blank, and naturally cooling it to room temperature after sintering to obtain a composite fiber reinforced refractory brick.

[0029] Furthermore, the ball milling speed during the ball milling in steps S1 and S2 is 1200-1500 rpm.

[0030] Furthermore, in step S3, the weight ratio of the mixture to water is 100:5-10.

[0031] Furthermore, the thermal sintering process in step S4 is a step-by-step temperature increase, and the step-by-step temperature increase procedure is as follows:

[0032] Thermal curing: 100-150°C, keep warm for 0.5-1.5h;

[0033] Pre-burning: 500-600℃, keep warm for 2-4h;

[0034] Post-firing: keep warm at 1000-1200℃ for 2-4h.

[0035] The beneficial effects of the present invention are:

[0036] The present invention provides a composite fiber-reinforced refractory brick and a preparation method thereof, comprising the following components: mullite, quartz, alumina, magnesia-alumina spinel fine powder, silicon carbide powder, composite fiber, and sodium tetrapolyphosphate. The composite fiber comprises modified zirconia fiber and magnesium metal fiber. The treated zirconia fiber is treated with a silane coupling agent. The unsaturated olefinic functional groups in the silane coupling agent structure serve as active initiation sites. The initiator initiates cross-linking polymerization of hydroxyethyl methacrylate and N,N-methylene acrylamide, which then react with active groups on the surface of the zirconia fiber, thereby loading macromolecular chains on the surface of the zirconia fiber. Under the action of a Pickering emulsion, the macromolecular chains serve as cross-linking points, causing the zirconia fibers to interconnect with each other, thereby constructing a three-dimensional network structure from the two-dimensional zirconia fiber to produce a modified zirconia fiber, thereby improving its mechanical toughness. Consequently, a refractory brick with high strength, strong mechanical toughness, and long service life is obtained. DETAILED DESCRIPTION

[0037] The technical solutions of the present invention are further described below by way of specific examples. Unless otherwise specified, the raw materials and equipment used in the present invention are all commercially available or commonly used in the art, and the methods in the examples are all conventional methods in the art unless otherwise specified.

[0038] Example 1

[0039] A composite fiber reinforced refractory brick is prepared from the following raw materials in parts by weight: 70 parts of mullite, 40 parts of quartz, 20 parts of alumina, 40 parts of magnesia-alumina spinel fine powder, 5 parts of silicon carbide powder, 1 part of composite fiber and 0.5 part of sodium tetrapolyphosphate. The aggregate has a particle size of 0.088 to 10 mm, wherein the Al2O3 content of the mullite fine powder is ≥68 wt%, the SiO2 content of the quartz is ≥92 wt%, and the Al2O3 content of the bauxite is ≥48 wt%; the particle size of the magnesia-alumina spinel fine powder is less than 0.088 mm, wherein the Al2O3 content is 71 to 85 wt%, and the (Al2O3 + MgO) content is 98 wt%; the particle size of the silicon carbide micropowder is less than 4 μm, wherein SiC ≥98 wt%; the composite fiber is composed of modified zirconia fiber and magnesium metal fiber, wherein the modified zirconia fiber accounts for 80 to 88 wt% and the balance is magnesium metal fiber; the diameter of the modified zirconia fiber is 0.02 to 0.1 mm and the length is 0.5 to 1 mm, and the diameter of the magnesium metal fiber is 0.2 to 1 mm and the length is 3 to 6 mm.

[0040] Furthermore, the preparation method of the modified zirconia fiber comprises the following steps:

[0041] SS1: Zirconia fiber was immersed in a 0.5% sodium carbonate solution for 4 hours, the material was centrifuged, washed and vacuum-dried, and then mixed with a mixed solution of ethanol and purified water in a volume ratio of 3:1. Ultrasonic dispersion was performed to form a uniform dispersion. A silane coupling agent was then added. The temperature was then raised to 60°C and stirred for 4 hours. The material was then cooled and discharged, and the solid material was separated by centrifugation.

[0042] SS2: The solid material is evenly dispersed in a mixed solution of ethanol and purified water in a volume ratio of 1:1. Hydroxyethyl methacrylate, N,N-methylene acrylamide, and an initiator are then added and stirred. The mixture is stirred at 90°C for 12 hours, and the solid material is separated to obtain a precursor.

[0043] SS3: Disperse the precursor in purified water, add emulsifier, mix evenly, continue to add cyclohexane and stir to form a stable emulsion, stir and emulsify at 60°C for 20 minutes, then add initiator, after addition, raise the temperature to 70°C, stir for 6 hours, separate the material, wash and freeze-dry to obtain modified zirconia fiber.

[0044] A composite fiber reinforced refractory brick and a preparation method thereof, specifically comprising the following steps:

[0045] S1: Aggregate and powder were mixed evenly, and then binder was added and ball milled at a speed of 1200 rpm for 5 min to obtain ball-milled aggregate;

[0046] S2: adding a sintering agent and a water reducing agent to the ball-milled aggregate obtained in step S1, and ball-milling at a rotation speed of 1200 rpm for 5 minutes to obtain a mixture;

[0047] S3: adding water to the mixture obtained in step S2, with the weight ratio of the mixture to water being 100:5, stirring evenly and pouring into a mold, vibrating and compacting in layers, letting it stand, and demolding to obtain refractory brick blanks;

[0048] S4: sintering the refractory brick blanks, and the step-by-step heating program is as follows: thermal curing: at 100°C, keeping warm for 0.5h; pre-firing: at 500°C, keeping warm for 2h; post-firing: at 1000°C, keeping warm for 2h. After sintering, naturally cool to room temperature to obtain composite fiber reinforced refractory bricks.

[0049] Example 2

[0050] A composite fiber reinforced refractory brick is prepared from the following raw materials in parts by weight: 80 parts of mullite, 50 parts of quartz, 30 parts of alumina, 60 parts of magnesia-alumina spinel fine powder, 10 parts of silicon carbide powder, 5 parts of composite fiber and 1 part of sodium tetrapolyphosphate. The aggregate has a particle size of 0.088 to 10 mm, wherein the Al2O3 content of the mullite fine powder is ≥68 wt%, the SiO2 content of the quartz is ≥92 wt%, and the Al2O3 content of the bauxite is ≥48 wt%; the particle size of the magnesia-alumina spinel fine powder is less than 0.088 mm, wherein the Al2O3 content is 71 to 85 wt%, and the (Al2O3 + MgO) content is 98 wt%; the particle size of the silicon carbide micropowder is less than 4 μm, wherein SiC ≥98 wt%; the composite fiber is composed of modified zirconia fiber and magnesium metal fiber, wherein the modified zirconia fiber accounts for 80 to 88 wt% and the balance is magnesium metal fiber; the diameter of the modified zirconia fiber is 0.02 to 0.1 mm and the length is 0.5 to 1 mm, and the diameter of the magnesium metal fiber is 0.2 to 1 mm and the length is 3 to 6 mm.

[0051] Furthermore, the preparation method of the modified zirconia fiber comprises the following steps:

[0052] SS1: Zirconia fiber was immersed in a 1% sodium carbonate solution for 6 hours, the material was centrifuged, washed and vacuum-dried, and then mixed with a mixed solution of ethanol and purified water in a volume ratio of 3:1. Ultrasonic dispersion was performed to form a uniform dispersion. A silane coupling agent was then added. The temperature was then raised to 70°C and stirred for 8 hours. The material was then cooled and discharged, and the solid material was separated by centrifugation.

[0053] SS2: The solid material is evenly dispersed in a mixed solution of ethanol and purified water in a volume ratio of 1:1. Hydroxyethyl methacrylate, N,N-methylene acrylamide, and an initiator are then added and stirred. The mixture is stirred at 100°C for 16 hours, and the solid material is separated to obtain a precursor.

[0054] SS3: Disperse the precursor in purified water, add emulsifier, mix evenly, continue to add cyclohexane and stir to form a stable emulsion, stir and emulsify at 80°C for 30 minutes, then add initiator, after addition, raise the temperature to 80°C, stir for 8 hours, separate the material, wash and freeze-dry to obtain modified zirconia fiber.

[0055] A composite fiber reinforced refractory brick and a preparation method thereof, specifically comprising the following steps:

[0056] S1: Aggregate and powder were mixed evenly, and then binder was added and ball milled at a speed of 1500 rpm for 15 min to obtain ball-milled aggregate;

[0057] S2: adding a sintering agent and a water reducing agent to the ball-milled aggregate obtained in step S1, and ball-milling at a rotation speed of 1500 rpm for 15 minutes to obtain a mixture;

[0058] S3: adding water to the mixture obtained in step S2, with the weight ratio of the mixture to water being 100:10, stirring evenly and pouring into a mold, vibrating and compacting in layers, letting it stand, and demolding to obtain refractory brick blanks;

[0059] S4: sintering the refractory brick blanks, and the step-by-step heating program is as follows: thermal curing: at 150°C, keeping warm for 1.5 hours; pre-firing: at 600°C, keeping warm for 4 hours; post-firing: at 1200°C, keeping warm for 4 hours. After sintering, naturally cool to room temperature to obtain composite fiber reinforced refractory bricks.

[0060] Example 3

[0061] A composite fiber reinforced refractory brick is prepared from the following raw materials in parts by weight: 75 parts of mullite, 45 parts of quartz, 25 parts of alumina, 50 parts of magnesia-alumina spinel fine powder, 7.5 parts of silicon carbide powder, 3 parts of composite fiber and 0.75 parts of sodium tetrapolyphosphate. The aggregate has a particle size of 0.088 to 10 mm, wherein the Al2O3 content of the mullite fine powder is ≥68 wt%, the SiO2 content of the quartz is ≥92 wt%, and the Al2O3 content of the bauxite is ≥48 wt%; the particle size of the magnesia-alumina spinel fine powder is less than 0.088 mm, wherein the Al2O3 content is 71 to 85 wt%, and the (Al2O3 + MgO) content is 98 wt%; the particle size of the silicon carbide micropowder is less than 4 μm, wherein SiC ≥98 wt%; the composite fiber is composed of modified zirconia fiber and magnesium metal fiber, wherein the modified zirconia fiber accounts for 80 to 88 wt% and the balance is magnesium metal fiber; the diameter of the modified zirconia fiber is 0.02 to 0.1 mm and the length is 0.5 to 1 mm, and the diameter of the magnesium metal fiber is 0.2 to 1 mm and the length is 3 to 6 mm.

[0062] Furthermore, the preparation method of the modified zirconia fiber comprises the following steps:

[0063] SS1: Zirconia fiber was immersed in a 0.75% sodium carbonate solution for 5 hours, and the material was centrifuged. After washing and vacuum drying, it was mixed with a mixed solution of ethanol and purified water in a volume ratio of 3:1, and ultrasonically dispersed to form a uniform dispersion. Silane coupling agent was then added, and the temperature was raised to 65°C. After stirring for 6 hours, the material was cooled and discharged, and the solid material was separated by centrifugation;

[0064] SS2: The solid material is evenly dispersed in a mixed solution of ethanol and purified water in a volume ratio of 1:1. Hydroxyethyl methacrylate, N,N-methylene acrylamide, and an initiator are then added and stirred. The mixture is stirred at 95°C for 15 hours, and the solid material is separated to obtain a precursor.

[0065] SS3: Disperse the precursor in purified water, add emulsifier, mix well, continue to add cyclohexane and stir to form a stable emulsion, stir and emulsify at 70°C for 25 minutes, then add initiator, after addition, raise the temperature to 75°C, stir for 7 hours, separate the material, wash and freeze-dry to obtain modified zirconia fiber.

[0066] A composite fiber reinforced refractory brick and a preparation method thereof, specifically comprising the following steps:

[0067] S1: Aggregate and powder were mixed evenly, and then binder was added and ball milled at 1350 rpm for 10 min to obtain ball-milled aggregate;

[0068] S2: adding a sintering agent and a water reducing agent to the ball-milled aggregate obtained in step S1, and ball-milling at a rotation speed of 1350 rpm for 10 minutes to obtain a mixture;

[0069] S3: adding water to the mixture obtained in step S2, with the weight ratio of the mixture to water being 100:7.5, stirring evenly and pouring into a mold, shaking and compacting in layers, letting it stand, and demolding to obtain refractory brick blanks;

[0070] S4: sintering the refractory brick blanks, and the step-by-step heating program is as follows: thermal curing: at 125°C, keeping warm for 1.0h; pre-firing: at 550°C, keeping warm for 3h; post-firing: at 1100°C, keeping warm for 3h. After sintering, naturally cool to room temperature to obtain composite fiber reinforced refractory bricks.

[0071] Comparative Example 1

[0072] The difference between Comparative Example 1 and Example 3 is that the zirconium oxide has not been modified.

[0073] Comparative Example 2

[0074] The difference between Comparative Example 2 and Example 3 is that the composite fiber contains only magnesium metal fibers.

[0075] Comparative Example 3

[0076] The difference between Comparative Example 3 and Example 3 is that the composite fiber contains only modified zirconia fiber.

[0077] Test results:

[0078] The flexural strength of the six samples obtained from the examples and comparative examples was measured according to the GB / T 3001-2007 standard. The results are shown in Table 1 below.

[0079] Table 1 Performance test results of the enhanced refractory bricks obtained in the examples and comparative examples

[0080]

[0081] As can be seen from Table 1, the mechanical toughness and strength of the example products are greater than those of the control group, and control 1 is greater than control 2 and control 3. This is mainly because the examples all contain composite fibers. The zirconia fibers in the composite fibers of control 1 have not been modified, while the composite fibers of control 2 and control 3 contain only magnesium metal fibers or modified zirconia fibers. When zirconia fibers are not modified, they have little effect on the toughness, refractoriness, and strength of refractory bricks at temperatures above 800°C. When only one type of fiber is included in the composite fibers, the effect on the performance of the refractory bricks is also greatly reduced. In the present invention, the composite fibers obtained by the synergistic effect of modified zirconia fibers and magnesium metal fibers can significantly improve the mechanical toughness, strength, and refractoriness of refractory bricks.

[0082] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to the specific embodiments described. Obviously, many modifications and variations are possible based on the content of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A composite fiber reinforced refractory brick, characterized in that: The invention comprises the following components in parts by weight: 70-80 parts of mullite, 40-50 parts of quartz, 20-30 parts of alumina, 40-60 parts of magnesia-alumina spinel fine powder, 5-10 parts of silicon carbide powder, 1-5 parts of composite fiber and 0.5-1 part of sodium tetrapolyphosphate.

2. A composite fiber reinforced refractory brick according to claim 1, characterized in that: The aggregate has a particle size of 0.088 to 10 mm, wherein the Al2O3 content of the mullite fine powder is ≥68 wt%, the SiO2 content of the quartz is ≥92 wt%, and the Al2O3 content of the bauxite is ≥48 wt%; the particle size of the magnesia-alumina spinel fine powder is less than 0.088 mm, wherein the Al2O3 content is 71 to 85 wt%, and the (Al2O3 + MgO) content is 98 wt%; the particle size of the silicon carbide micropowder is less than 4 μm, wherein SiC is ≥98 wt%.

3. The composite fiber reinforced refractory brick according to claim 1, characterized in that: The composite fiber is composed of modified zirconia fiber and magnesium metal fiber, wherein the modified zirconia fiber accounts for 80-88wt% and the balance is magnesium metal fiber; the diameter of the modified zirconia fiber is 0.02-0.1mm and the length is 0.5-1mm, and the diameter of the magnesium metal fiber is 0.2-1mm and the length is 3-6mm.

4. The composite fiber reinforced refractory brick according to claim 3, characterized in that: The preparation method of the modified zirconia fiber comprises the following steps: SS1: Immerse the zirconia fiber in a 0.5% to 1% sodium carbonate solution for 4 to 6 hours, centrifuge the material, wash and vacuum dry it, and then mix it with a mixed solution of ethanol and purified water in a volume ratio of 3:

1. Ultrasonic dispersion is performed to form a uniform dispersion. A silane coupling agent is then added. The temperature is then raised to 60 to 70°C, stirred for 4 to 8 hours, cooled, discharged, and the solid material is separated by centrifugation. SS2: After the solid material is evenly dispersed in a mixed solution of ethanol and purified water in a volume ratio of 1:1, hydroxyethyl methacrylate, N,N-methylene acrylamide and initiator are added and stirred evenly. After stirring at 90-100°C for 12-16 hours, the solid material is separated to obtain a precursor; SS3: Disperse the precursor in purified water, add emulsifier, mix evenly, continue to add cyclohexane and stir evenly to form a stable emulsion, stir and emulsify at 60-80°C for 20-30 minutes, then add initiator, after addition, raise the temperature to 70-80°C, stir for 6-8 hours, separate the material, wash and freeze-dry to obtain modified zirconia fiber.

5. The kaolin powder ultrafine grinding medium according to claim 4, characterized in that: The silane coupling agent in step SS1 is any one of methyl acrylate propylene glycol or 3-(methacryloyloxy)propyltrimethoxysilane.

6. The composite fiber reinforced refractory brick according to claim 4, characterized in that: In step SS2 and step SS3, the initiator is any one of vinyl nitrate and ethyl peroxypropionate.

7. The composite fiber reinforced refractory brick according to claim 4, characterized in that: In step SS3, the emulsifier is any one of sodium lauryl sulfonate or sodium lauryl phosphate.

8. The composite fiber reinforced refractory brick according to claim 2, characterized in that: In the step 3), the weight ratio of kaolin material to nano zinc oxide is 1:20-30.

9. A method for preparing a composite fiber reinforced refractory brick according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: S1: Mix the aggregate and powder evenly, then add the binder and ball mill for 5-15 minutes to obtain ball-milled aggregate; S2: adding a sintering agent and a water reducing agent to the ball-milled aggregate obtained in step S1, and ball-milling for 5 to 15 minutes to obtain a mixture; S3: adding water to the mixture obtained in step S2, stirring evenly, pouring into a mold, shaking and compacting in layers, letting it stand, and demolding to obtain refractory brick blanks; S4: sintering the refractory brick blank, and naturally cooling it to room temperature after sintering to obtain a composite fiber reinforced refractory brick.

10. The method for preparing composite fiber reinforced refractory bricks according to claim 9, characterized in that: The ball milling speed in steps S1 and S2 is 1200-1500 rpm; the weight ratio of the mixture to water in step S3 is 100:5-10; the thermal sintering treatment in step S4 is a stepwise heating process, and the stepwise heating process is as follows: thermal curing: 100-150° C., heat preservation for 0.5-1.5 hours; Pre-firing: 500-600℃, keep warm for 2-4h; post-firing: 1000-1200℃, keep warm for 2-4h.

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