Refractory heat-insulating brick and preparation method thereof

Abstract

The method comprises the following steps that S1, dry materials and a binding agent are provided, and the dry materials comprise 19 wt%-24 wt% of intaglio corundum with the particle size being 3-5 mm, 22 wt%-35 wt% of intaglio corundum with the particle size being 1-3 mm, 12 wt%-19 wt% of white corundum with the particle size being 0-1 mm, 18 wt%-24 wt% of white corundum fine powder with the particle size being smaller than 200 meshes and 2 wt%-4 wt% of composite metal powder; s2, the dry material and a binding agent are mixed and ground, and a mixed and ground material is obtained; and S3, molding and drying the mixed and ground material to obtain the fire-resistant heat-insulating brick. The refractory brick produced by adopting the inked corundum and the white corundum as main raw materials, adding the composite metal powder and adding the additional binding agent has the advantages of high strength, good thermal shock resistance, good permeability resistance, good erosion resistance and long service life, and can be widely applied to rotary kilns, cement kilns and other parts.

Description

Technical Field

[0001] This invention relates to the field of heat-insulating brick technology, and in particular to a refractory heat-insulating brick and its preparation method. Background Technology

[0002] Insulating bricks are mostly lightweight bricks. This type of brick can play a role in heat insulation when used in permanent layers, but it reduces the thickness of the working layer and limits the service life of the parts used.

[0003] Research has revealed that C2M2A in the phase structure of graphite corundum material 14 The composition is 45%–58%, CA 68%–13%, and MA 25%–47%. All three phases are high-melting-point phases, and the lowest eutectic temperature of the system reaches 1778℃, giving it high-temperature resistance as a refractory material. Furthermore, all three phases exhibit good resistance to alkali corrosion. 14 Due to their special structure, the CA6 phase has a low thermal conductivity coefficient. Refractory bricks prepared using this multiphase material as aggregate can achieve the basic service life of ordinary refractory materials and also provide thermal insulation.

[0004] In view of this, improvements should be made to the existing technology. Summary of the Invention

[0005] The main objective of this invention is to provide a refractory insulating brick and its preparation method. Using black corundum and white corundum as main raw materials, and by adding composite metal powder and an external binder, the produced refractory brick exhibits advantages such as high strength, good thermal shock stability, good impermeability, good erosion resistance, and long service life. It can be widely applied in rotary kilns and cement kilns. This type of spinel brick has good erosion resistance, is suitable for calcination in various alkaline rotary kilns, and has a long service life. Preliminary experimental results in rotary kilns have yielded promising results. The successful development and application of this refractory insulating brick not only reduces the cost of refractory materials, resulting in high economic benefits, but also ensures the service life of rotary kilns, reduces kiln lining temperature, and represents a significant breakthrough in energy saving in rotary kilns. It has good economic benefits and excellent market application prospects.

[0006] According to one aspect of the present invention, a method for preparing refractory insulating bricks is provided, comprising the following steps: S1. Provide dry materials and binders. The dry materials include 19-24 wt% of black corundum with a particle size of 3-5 mm, 22-35 wt% of black corundum with a particle size of 1-3 mm, 12-19 wt% of white corundum with a particle size of 0-1 mm, 18-24 wt% of white corundum fine powder with a particle size of less than 200 mesh, and 2-4 wt% of composite metal powder. S2. Mix the dry material and binder to obtain the mixed material; S3. The mixed material is shaped and dried to obtain refractory and heat-insulating bricks.

[0007] According to an embodiment of the present invention, in step S2, the mixing and milling specifically includes: first, mixing and milling black corundum with a particle size of 3-5 mm, black corundum with a particle size of 1-3 mm, and white corundum with a particle size of 0-1 mm at a low speed of 60-150 r / min for t1 minutes; then adding 40-60 wt% of binder and mixing and milling at a low speed of 60-150 r / min for t2 minutes; then adding the remaining binder and mixing and milling at a low speed for t3 minutes; finally adding white corundum fine powder and composite metal powder and mixing and milling at a high speed of 600-1000 r / min for t4 minutes; and finally discharging the mixed material.

[0008] According to one embodiment of the present invention, in step S3, the drying includes: first natural drying and then drying in a drying kiln under predetermined drying conditions, wherein the predetermined drying conditions specifically include: a drying temperature of 180 to 200°C and a drying time of 8 to 16 hours.

[0009] According to one embodiment of the present invention, t1 is 1 to 2 minutes, t2 is 1 to 2 minutes, t3 is 1 to 2 minutes, and t4 is not less than 8 minutes.

[0010] According to one embodiment of the present invention, the temperature of the mixed material discharged at the end of the mixing process is controlled at 35-55°C based on the air temperature.

[0011] According to another aspect of the present invention, a refractory insulating brick is provided, comprising dry material and a binder, wherein the dry material comprises: 19–24 wt% of black corundum with a particle size of 3–5 mm, 22–35 wt% of black corundum with a particle size of 1–3 mm, 12–19 wt% of white corundum with a particle size of 0–1 mm, 18–24 wt% of white corundum fine powder with a particle size of less than 200 mesh, and 2–4 wt% of composite metal powder with a particle size of less than 150 mesh.

[0012] According to one embodiment of the present invention, the composite metal powder is a mixture of aluminum powder and silicon powder, and the particle size is controlled between 200 mesh and 180 mesh.

[0013] According to one embodiment of the present invention, the mass ratio of aluminum powder to silicon powder is 0.5 to 5:1.

[0014] According to one embodiment of the present invention, the ratio of dry material to binder is (70~75):(2.5~3).

[0015] According to one embodiment of the present invention, the binder is an aluminum dihydrogen phosphate solution with a concentration of 2-4 wt%.

[0016] According to an embodiment of the present invention, a method for preparing refractory insulating bricks uses black corundum and white corundum as the main raw materials. By adding composite metal powder and an external binder, the resulting refractory bricks possess advantages such as high strength, good thermal shock stability, good impermeability, good erosion resistance, and long service life. They can be widely used in rotary kilns and cement kilns. These spinel bricks exhibit good erosion resistance and are suitable for calcination in various alkaline rotary kilns. They have a long service life, and initial experimental results in rotary kilns have yielded promising results. The successful development and application of this refractory insulating brick not only reduces the cost of refractory materials, resulting in high economic benefits, but also ensures the service life of rotary kilns, reduces kiln lining temperature, and represents a significant breakthrough in energy conservation in rotary kilns. It has excellent economic benefits and promising prospects for market promotion and application. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some implementation examples of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A process flow diagram of a method for preparing a refractory insulating brick according to an exemplary embodiment of the present invention is shown. Detailed Implementation

[0019] The following detailed description of the embodiments is intended to exemplify the principles of the present invention, but should not be construed as limiting the scope of the invention. The present invention can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0020] These embodiments are provided to make this disclosure thorough and complete, and to fully express the scope of the invention to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, material composition, numerical expressions, and values ​​set forth in these embodiments should be interpreted as merely exemplary and not as limiting.

[0021] It should be noted that, in the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationships, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0022] It should also be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention depending on the specific circumstances. When a specific device is described as being located between a first device and a second device, an intermediary device may or may not be present between the specific device and the first or second device.

[0023] All terms used in this invention have the same meaning as understood by one of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and not as idealized or highly formalized, unless expressly defined herein.

[0024] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0025] like Figure 1 As shown, the present invention provides a method for preparing refractory and heat-insulating bricks, which includes the following steps: S1. Provide dry materials and binders. The dry materials include 19-24 wt% of black corundum with a particle size of 3-5 mm, 22-35 wt% of black corundum with a particle size of 1-3 mm, 12-19 wt% of white corundum with a particle size of 0-1 mm, 18-24 wt% of white corundum fine powder with a particle size of less than 200 mesh, and 2-4 wt% of composite metal powder. S2. Mix the dry material and binder to obtain the mixed material; S3. The mixed material is shaped and dried to obtain refractory and heat-insulating bricks.

[0026] In the preparation method of refractory insulating bricks according to embodiments of the present invention, black corundum and white corundum are used as the main raw materials. By adding composite metal powder and an external binder, the produced refractory bricks have advantages such as high strength, good thermal shock stability, good impermeability, good erosion resistance, and long service life. They can be widely used in rotary kilns and cement kilns. These spinel bricks have good erosion resistance and are suitable for calcination in various alkaline rotary kilns. They have a long service life, and preliminary test results in rotary kilns have yielded good results. The successful development and application of these refractory insulating bricks not only reduces the cost of refractory materials and has high economic benefits, but also ensures the service life of rotary kilns, reduces kiln lining temperature, and achieves a major breakthrough in energy saving in rotary kilns. They have good economic benefits and promising prospects for market promotion and application.

[0027] The physicochemical properties of the main refractory raw materials (such as black fused alumina and white fused alumina) in refractory insulating bricks are shown in Table 1.

[0028] Table 1. Physicochemical properties of main refractory raw materials for refractory insulating bricks

[0029] The physicochemical properties of the refractory insulating bricks prepared using the above technical solution are shown in Table 2.

[0030] Table 2 Physicochemical Properties of Refractory Insulating Bricks

[0031] In some specific embodiments, step S2, the mixing and grinding specifically includes: first, mixing and grinding black corundum with a particle size of 3-5 mm, black corundum with a particle size of 1-3 mm, and white corundum with a particle size of 0-1 mm at a low speed of 60-150 r / min for t1 minutes; then adding 40-60 wt% binder and mixing and grinding at a low speed of 60-150 r / min for t2 minutes; then adding the remaining binder and mixing and grinding at a low speed for t3 minutes; finally adding white corundum fine powder and composite metal powder and mixing and grinding at a high speed of 600-1000 r / min for t4 minutes; and then discharging the mixed material.

[0032] The first low-speed mixing process initially mixes coarse aggregate with some fine powder, breaking up raw material agglomerates and achieving "coarse dispersion" to avoid localized accumulation of fine powder. The second low-speed mixing process involves adding a binder and gently stirring it to allow the binder to initially coat the particle surface, forming a "preliminary coating layer" to prevent excessive localized viscosity caused by binder concentration. The third low-speed mixing process adjusts the moisture content, allowing moisture to evenly penetrate into all particle gaps, solving the problem of localized excessive dryness or wetness, and laying the groundwork for the microscopic uniformity of subsequent high-speed mixing.

[0033] After low-speed mixing and milling, the raw materials have achieved macroscopic uniformity, but the interfacial bonding between the binder and the aggregate / fine powder is still relatively loose. High-speed mixing and milling, through strong shearing and extrusion, can force the binder to coat the particle surface and even allow some fine powder to fill the aggregate pores, forming a tighter interfacial bond. This significantly improves the room temperature strength of the green body (such as flexural strength and compressive strength) and reduces the risk of cracking during handling or drying after molding.

[0034] Based on the above embodiments, step S3 includes drying by first naturally drying and then drying in a drying kiln under predetermined drying conditions, wherein the predetermined drying conditions specifically include drying temperature of 180-200°C and drying time of 8-16 hours.

[0035] Refractory insulating brick blanks contain free water and bound water. If the temperature is below 180℃, the free water evaporates slowly, and the bound water is difficult to remove, which can easily lead to an excessively long drying cycle. Furthermore, the internal structure of the blank is prone to internal stress due to uneven moisture distribution. If the temperature is above 200℃, the surface moisture will form a "hard shell" due to violent evaporation, which will hinder the diffusion of internal moisture outward, resulting in "dry outside and wet inside". This can lead to defects such as cracking and blistering (especially for blanks containing lightweight porous aggregates, whose pore structure is easily damaged by the rapid expansion of moisture).

[0036] A medium-high temperature environment of 180-200℃ allows moisture to evaporate slowly in a gradient from the inside of the billet to the surface, ensuring a match between the internal and external dehydration rates and significantly reducing the risk of cracking.

[0037] In some specific embodiments, t1 is 1 to 2 minutes, t2 is 1 to 2 minutes, t3 is 1 to 2 minutes, and t4 is no less than 8 minutes.

[0038] Based on the above embodiments, the temperature of the mixed material discharged at the end of the mixing process is controlled between 35 and 55°C, depending on the ambient temperature. A temperature of 35 to 55°C allows the binder to maintain its optimal viscosity range, which not only evenly disperses and coats the material particles but also promotes the "bridging" between fine powder and aggregate through viscosity, significantly improving the uniformity of mixing.

[0039] The present invention also proposes a refractory insulating brick, which comprises dry material and a binder, wherein the dry material comprises: 19–24 wt% of black corundum with a particle size of 3–5 mm, 22–35 wt% of black corundum with a particle size of 1–3 mm, 12–19 wt% of white corundum with a particle size of 0–1 mm, 18–24 wt% of white corundum fine powder with a particle size of less than 200 mesh, and 2–4 wt% of composite metal powder with a particle size of less than 150 mesh.

[0040] In some specific embodiments, the composite metal powder is a mixture of aluminum powder and silicon powder, with a particle size controlled between 200 mesh and 180 mesh. Coarse metal powder (>180 mesh) tends to form rigid particles in the billet, which can easily lead to mold wear during molding and cause defects such as scratches and dents on the surface of the billet. Particles with a particle size of 200 mesh to 180 mesh have moderate flowability, are easy to disperse during mixing and rolling, and are easy to compact during molding, which can reduce equipment wear and improve production efficiency.

[0041] Based on the above embodiments, the mixing mass ratio of aluminum powder and silicon powder is 0.5 to 5:1.

[0042] In some specific embodiments, the black corundum is an electrofused two-phase or three-phase material of MA, CA2 and CA6.

[0043] Based on the above embodiments, the ratio of dry material to binder is (70~75):(2.5~3).

[0044] In some specific embodiments, the binder is a 2-4 wt% aluminum dihydrogen phosphate solution. Aluminum dihydrogen phosphate is readily soluble in water, forming a viscous acidic solution (pH ≈ 2-3) upon addition of water, in which Al... 3+ With H2PO4 - Ions can be adsorbed onto the surface of aggregates and fine powders through hydrogen bonds and van der Waals forces, forming a continuous colloidal film that binds the particles together.

[0045] The following specific embodiments further illustrate this solution.

[0046] Example 1 A method for preparing a refractory insulating brick, characterized by comprising the following steps: S1. Prepare black corundum into 3~5mm and 1~3mm specifications; S2. Add 22wt% of 3-5mm black corundum, 28wt% of 1-3mm black corundum, and 15wt% of 0-1mm white corundum to a high-speed mixer and mix at low speed for 1-2 minutes; then add 1.4wt% of liquid aluminum dihydrogen phosphate and mix at low speed for 1-2 minutes; then add the remaining 1.4wt% of liquid aluminum dihydrogen phosphate and mix at low speed for 1-2 minutes; finally add 31wt% of white corundum fine powder (less than 200 mesh) and 4wt% of composite metal powder and mix at high speed for no less than 8 minutes. S3. After the mixing and grinding is completed, the discharge temperature of the mixed material is controlled at 35-60℃ according to the air temperature. The mixed material is automatically formed by a friction brick press with a tonnage of 630t or above. After the qualified formed products are naturally dried for 24 hours, they are put into a tunnel drying kiln and dried at 180-200℃ for 16 hours. After drying, the qualified products are selected as refractory heat insulation bricks.

[0047] The raw material composition of refractory insulating bricks is shown in Table 1.

[0048] The composite metal powder is a mixture of 200-mesh aluminum powder and 180-mesh silicon powder in a ratio of 5:1.

[0049] The added binder is aluminum dihydrogen phosphate solution.

[0050] Example 2 A method for preparing a refractory insulating brick, characterized by comprising the following steps: S1. Prepare black corundum into 3~5mm and 1~3mm specifications; S2. Add 22wt% of 3-5mm black corundum, 28wt% of 1-3mm black corundum, and 15wt% of 0-1mm white corundum to a high-speed mixer and mix at low speed for 1-2 minutes; then add 1.4wt% of liquid aluminum dihydrogen phosphate and mix at low speed for 1-2 minutes; then add the remaining 1.4wt% of liquid aluminum dihydrogen phosphate and mix at low speed for 1-2 minutes; finally add 31wt% of white corundum fine powder (less than 200 mesh) and 4wt% of composite metal powder and mix at high speed for no less than 8 minutes. S3. After the mixing and grinding is completed, the discharge temperature of the mixed material is controlled at 35-60℃ according to the air temperature. The mixed material is automatically formed by a friction brick press with a tonnage of 630t or above. After the qualified formed products are naturally dried for 24 hours, they are put into a tunnel drying kiln and dried at 180-200℃ for 16 hours. After drying, the qualified products are selected as refractory heat insulation bricks.

[0051] The raw material composition of refractory insulating bricks is shown in Table 1.

[0052] The composite metal powder is a mixture of 200-mesh aluminum powder and 180-mesh silicon powder in a ratio of 4:1.

[0053] The added binder is aluminum dihydrogen phosphate solution.

[0054] Example 3 A method for preparing a refractory insulating brick, characterized by comprising the following steps: S1. Prepare black corundum into 3~5mm and 1~3mm specifications; S2. Add 22wt% of 3-5mm black corundum, 28wt% of 1-3mm black corundum, and 15wt% of 0-1mm white corundum to a high-speed mixer and mix at low speed for 1-2 minutes; then add 1.4wt% of liquid aluminum dihydrogen phosphate and mix at low speed for 1-2 minutes; then add the remaining 1.4wt% of liquid aluminum dihydrogen phosphate and mix at low speed for 1-2 minutes; finally add 31wt% of white corundum fine powder (less than 200 mesh) and 4wt% of composite metal powder and mix at high speed for no less than 8 minutes. S3. After the mixing and grinding is completed, the discharge temperature of the mixed material is controlled at 35-60℃ according to the air temperature. The mixed material is automatically formed by a friction brick press with a tonnage of 630t or above. After the qualified formed products are naturally dried for 24 hours, they are put into a tunnel drying kiln and dried at 180-200℃ for 16 hours. After drying, the qualified products are selected as refractory heat insulation bricks.

[0055] The raw material composition of refractory insulating bricks is shown in Table 1.

[0056] The composite metal powder is a mixture of 200-mesh aluminum powder and 180-mesh silicon powder in a ratio of 2:1.

[0057] The added binder is aluminum dihydrogen phosphate solution.

[0058] Example 4 A method for preparing a refractory insulating brick, characterized by comprising the following steps: S1. Prepare black corundum into 3~5mm and 1~3mm specifications; S2. Add 22wt% of 3-5mm black corundum, 28wt% of 1-3mm black corundum, and 15wt% of 0-1mm white corundum to a high-speed mixer and mix at low speed for 1-2 minutes; then add 1.4wt% of liquid aluminum dihydrogen phosphate and mix at low speed for 1-2 minutes; then add the remaining 1.4wt% of liquid aluminum dihydrogen phosphate and mix at low speed for 1-2 minutes; finally add 31wt% of white corundum fine powder (less than 200 mesh) and 4wt% of composite metal powder and mix at high speed for no less than 8 minutes. S3. After the mixing and grinding is completed, the discharge temperature of the mixed material is controlled at 35-60℃ according to the air temperature. The mixed material is automatically formed by a friction brick press with a tonnage of 630t or above. After the qualified formed products are naturally dried for 24 hours, they are put into a tunnel drying kiln and dried at 180-200℃ for 16 hours. After drying, the qualified products are selected as refractory heat insulation bricks.

[0059] The raw material composition of refractory insulating bricks is shown in Table 1.

[0060] The composite metal powder is a mixture of 200-mesh aluminum powder and 180-mesh silicon powder in a 1:1 ratio.

[0061] The added binder is aluminum dihydrogen phosphate solution.

[0062] Example 5 A method for preparing a refractory insulating brick, characterized by comprising the following steps: S1. Prepare black corundum into 3~5mm and 1~3mm specifications; S2. Add 22wt% of 3-5mm black corundum, 28wt% of 1-3mm black corundum, and 15wt% of 0-1mm white corundum to a high-speed mixer and mix at low speed for 1-2 minutes; then add 1.4wt% of liquid aluminum dihydrogen phosphate and mix at low speed for 1-2 minutes; then add the remaining 1.4wt% of liquid aluminum dihydrogen phosphate and mix at low speed for 1-2 minutes; finally add 31wt% of white corundum fine powder (less than 200 mesh) and 4wt% of composite metal powder and mix at high speed for no less than 8 minutes. S3. After the mixing and grinding is completed, the discharge temperature of the mixed material is controlled at 35-60℃ according to the air temperature. The mixed material is automatically formed by a friction brick press with a tonnage of 630t or above. After the qualified formed products are naturally dried for 24 hours, they are put into a tunnel drying kiln and dried at 180-200℃ for 16 hours. After drying, the qualified products are selected as refractory heat insulation bricks.

[0063] The raw material composition of refractory insulating bricks is shown in Table 1.

[0064] The composite metal powder is a mixture of 200-mesh aluminum powder and 180-mesh silicon powder in a ratio of 0.5:1.

[0065] The added binder is aluminum dihydrogen phosphate solution.

[0066] The above are exemplary embodiments disclosed in this invention. The order of the disclosed embodiments is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. However, it should be noted that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the disclosed embodiments of this invention (including the claims) is limited to these examples. Various changes and modifications can be made without departing from the scope defined by the claims. The functions, steps, and / or actions of the methods according to the disclosed embodiments described herein do not need to be performed in any particular order. Furthermore, although the elements disclosed in the embodiments of this invention may be described or claimed individually, they may be understood as multiple unless explicitly limited to a singular.

[0067] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples. Within the framework of the invention, technical features of the above embodiments or different embodiments can be combined, and many other variations of the different aspects of the invention as described above exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.

Claims

1. A method for preparing a refractory insulating brick, characterized in that, Includes the following steps: S1. Provide dry materials and binders, wherein the dry materials include 19-24 wt% of black corundum with a particle size of 3-5 mm, 22-35 wt% of black corundum with a particle size of 1-3 mm, 12-19 wt% of white corundum with a particle size of 0-1 mm, 18-24 wt% of white corundum fine powder with a particle size of less than 200 mesh, and 2-4 wt% of composite metal powder; S2. The dry material and the binder are mixed and milled to obtain a mixed material; S3. The mixed material is shaped and dried to obtain refractory and heat-insulating bricks.

2. The method for preparing refractory and heat-insulating bricks according to claim 1, characterized in that, In step S2, the mixing and milling specifically includes: first, mixing and milling black corundum with a particle size of 3-5 mm, black corundum with a particle size of 1-3 mm, and white corundum with a particle size of 0-1 mm at a low speed of 60-150 r / min for t1 minutes; then adding 40-60 wt% binder and mixing and milling at a low speed of 60-150 r / min for t2 minutes; then adding the remaining binder and mixing and milling at a low speed for t3 minutes; finally adding white corundum fine powder and composite metal powder and mixing and milling at a high speed of 600-1000 r / min for t4 minutes; and then discharging the mixed material.

3. The method for preparing refractory and heat-insulating bricks according to claim 1, characterized in that, In step S3, the drying process includes: first, natural drying, and then drying in a drying kiln under predetermined drying conditions, wherein the predetermined drying conditions specifically include: a drying temperature of 180 to 200°C and a drying time of 8 to 16 hours.

4. The method for preparing refractory and heat-insulating bricks according to claim 2, characterized in that, The t1 is 1 to 2 minutes, the t2 is 1 to 2 minutes, the t3 is 1 to 2 minutes, and the t4 is no less than 8 minutes.

5. The method for preparing refractory and heat-insulating bricks according to claim 2, characterized in that, The temperature of the mixed material discharged at the end of the mixing process should be controlled between 35 and 55°C, depending on the ambient temperature.

6. A refractory and heat-insulating brick, characterized in that, The refractory insulating brick comprises dry material and a binder, wherein the dry material includes: 19–24 wt% of black corundum with a particle size of 3–5 mm, 22–35 wt% of black corundum with a particle size of 1–3 mm, 12–19 wt% of white corundum with a particle size of 0–1 mm, 18–24 wt% of white corundum fine powder with a particle size of less than 200 mesh, and 2–4 wt% of composite metal powder with a particle size of less than 150 mesh.

7. The refractory insulating brick according to claim 6, characterized in that, The composite metal powder is a mixture of aluminum powder and silicon powder, with a particle size controlled between 200 mesh and 180 mesh.

8. The refractory insulating brick according to claim 7, characterized in that, The mass ratio of the aluminum powder to the silicon powder is 0.5 to 5:

1.

9. The refractory insulating brick according to claim 6, characterized in that, The ratio of the dry material to the binder is (70~75):(2.5~3).

10. The refractory insulating brick according to claim 6, characterized in that, The binder is an aluminum dihydrogen phosphate solution with a concentration of 2-4 wt%.

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