Refractory castable

Abstract

The invention relates to a refractory castable. The refractory castable is prepared from the following raw materials: first aggregate, lightweight aggregate with a porous structure, powder, a binding agent, a water reducing agent and refractory fibers, wherein the content of the first aggregate is 35%-55% by mass, the content of the lightweight aggregate is 5%-15% by mass, the content of the powder material is 30%-40% by mass, the content of the binding agent is 5%-10% by mass, the content of the water reducing agent is 0.5%-1.5% by mass, and the content of the refractory fiber is 1%-2% by mass. The refractory castable provided by the invention is a light-weight heat-preservation refractory castable with small density, low thermal conductivity, good heat preservation performance and good high-temperature use performance, heat storage loss and heat dissipation loss of a furnace body are reduced while the use conditions of an industrial furnace and high-temperature equipment are met, and the purposes of saving energy, reducing consumption and prolonging the service life of the furnace are achieved.

Description

Technical Field

[0001] The present application relates to the technical field of refractory materials, and in particular to a refractory castable. Background Art

[0002] Refractory materials are an indispensable part of industrial kilns and high-temperature equipment. They can withstand extreme high temperatures and erosion by molten materials, protecting the safe operation of equipment. As the basic material of high-temperature industry, they undoubtedly play an important role in energy saving and consumption reduction of industrial kilns and high-temperature equipment.

[0003] The traditional refractory castables currently used in high-temperature industries have a large density, resulting in high heat capacity, low thermal efficiency, and large heat storage losses; high thermal conductivity, large heat dissipation losses in the furnace body, and high energy consumption. The high density of the refractory material also causes the refractory lining of the kiln to be heavy and the heat transfer to be fast. It cannot effectively protect the steel structure from the influence of high temperature, which is one of the factors that cause the deformation of the furnace shell structure and affect the service life. Therefore, it is urgent to develop a lightweight thermal insulation refractory castable with low density, low thermal conductivity, good thermal insulation performance, and good high-temperature performance. While meeting the use conditions of industrial kilns and high-temperature equipment, it can reduce the heat storage loss and heat dissipation loss of the furnace body, so as to achieve the purpose of energy saving and consumption reduction and increase the service life of the kiln. Summary of the invention

[0004] The present application provides a refractory castable to solve the following technical problem: how to improve the performance of the refractory castable.

[0005] In a first aspect, the present application provides a refractory castable, wherein the raw materials of the refractory castable include: a first aggregate, a lightweight aggregate with a porous structure, a powder, a binder, a water reducing agent, and a refractory fiber; wherein, in terms of mass fraction,

[0006] The content of the first aggregate is 35% to 55%, the content of the lightweight aggregate is 5% to 15%, the content of the powder is 30% to 40%, the content of the binder is 5% to 10%, the content of the water reducer is 0.5% to 1.5%, and the content of the refractory fiber is 1% to 2%.

[0007] Optionally, the lightweight aggregate includes at least one of the following: porous kaolinite and porous pyrophyllite.

[0008] Optionally, the lightweight aggregate is obtained by impregnating a lightweight aggregate matrix with resin.

[0009] Optionally, the resin includes at least one of the following: phenolic resin, epoxy resin, and furan resin.

[0010] Optionally, the powder includes: high-alumina bauxite powder, aluminum powder and silicon powder.

[0011] Optionally, the weight ratio of the high-alumina bauxite powder M1, the aluminum powder M2 and the silicon powder M3 is M1:M2:M3 (6-8):(3-4):(6-8).

[0012] Optionally, the first aggregate includes at least one of the following: sintered corundum, high-alumina bauxite, and mullite.

[0013] Optionally, the binder includes at least one of the following: silica sol and aluminum sol.

[0014] Optionally, the water reducing agent includes at least one of the following: naphthalene sulfonate formaldehyde condensate, melamine sulfonate formaldehyde condensate, and lignin sulfonate.

[0015] Optionally, the refractory castable meets the following properties: bulk density <2.0 g / cm 3 , thermal conductivity (average 350℃) <0.8W / mK, compressive strength at 110℃×24h>12MPa, compressive strength at 1500℃×3h>34MPa, thermal shock stability performance 1100℃ water cooling ≥30 times.

[0016] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0017] The refractory castable provided in the embodiment of the present application has a first aggregate which can improve the refractoriness and strength of the refractory castable, and improve the thermal shock stability of the refractory castable; a lightweight aggregate with a porous structure can significantly reduce the overall density of the castable, thereby reducing the weight of the refractory castable, and the porous structure helps to reduce the thermal conductivity of the refractory castable, improve the thermal insulation performance of the refractory castable, and absorb and relieve stress to a certain extent, reducing the generation of cracks; the powder can improve the fluidity and density of the refractory castable; the binder can improve the bonding strength between the components of the castable; the water reducer can improve the fluidity of the refractory castable and reduce the water consumption; the refractory fiber can improve the toughness of the castable and crack resistance; the first aggregate and the lightweight aggregate jointly provide structural support for the castable; the powder is filled between the first aggregate and the lightweight aggregate to form a tight stack together, increase the density of the castable, provide fluidity during construction, and help improve the strength and corrosion resistance of the castable; the binder, the first aggregate, the lightweight aggregate and the powder react physically and chemically to form a network structure to enhance the bonding strength and overall performance of the castable; the water reducer can reduce the amount of the binder while maintaining the fluidity of the castable, which helps to improve the construction performance of the castable and reduce the formation of pores; and the raw materials of the above-mentioned refractory castable interact with each other at high temperature to react chemically, further enhancing the performance of the refractory castable. Therefore, the refractory castable is a lightweight thermal insulation refractory castable with low density, low thermal conductivity, good thermal insulation performance, and good high-temperature performance. While meeting the use conditions of industrial kilns and high-temperature equipment, it reduces the heat storage loss and heat dissipation loss of the furnace body, achieving the purpose of energy saving and consumption reduction and increasing the service life of the kiln. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0019] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0020] Figure 1 A schematic flow chart of a method for preparing a refractory castable provided in an embodiment of the present application. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0022] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0023] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present application specification, the terms "include", "comprise", etc. refer to "including but not limited to". In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "at least one" refers to one or more, and "multiple" refers to two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can all represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, wherein a, b, c can be single or multiple, respectively.

[0024] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0025] In a first aspect, the present application provides a refractory castable, wherein the raw materials of the refractory castable include: a first aggregate, a lightweight aggregate with a porous structure, a powder, a binder, a water reducing agent, and a refractory fiber; wherein, in terms of mass fraction,

[0026] The content of the first aggregate is 35% to 55%, the content of the lightweight aggregate is 5% to 15%, the content of the powder is 30% to 40%, the content of the binder is 5% to 10%, the content of the water reducer is 0.5% to 1.5%, and the content of the refractory fiber is 1% to 2%.

[0027] In the embodiment of the present application, the first aggregate can improve the refractoriness and strength of the refractory castable, and improve the thermal shock stability of the refractory castable; the lightweight aggregate with a porous structure can significantly reduce the overall density of the castable, thereby reducing the weight of the refractory castable, and the porous structure helps to reduce the thermal conductivity of the refractory castable, improve the thermal insulation performance of the refractory castable, and absorb and relieve stress to a certain extent, reducing the generation of cracks; the powder can improve the fluidity and density of the refractory castable; the binder can improve the bonding strength between the components of the castable; the water reducer can improve the fluidity of the refractory castable; the refractory fiber can improve the toughness and crack resistance of the castable; the first aggregate The first aggregate and the lightweight aggregate together provide structural support for the castable; the powder is filled between the first aggregate and the lightweight aggregate to form a tight stack, which increases the density of the castable, provides fluidity during construction, and helps to improve the strength and corrosion resistance of the castable; the binder, the first aggregate, the lightweight aggregate and the powder undergo a physical and chemical reaction to form a network structure, which enhances the bonding strength and overall performance of the castable; the water reducer can reduce the amount of binder and water used while maintaining the fluidity of the castable, which helps to improve the construction performance of the castable and reduce the formation of pores; and the raw materials of the above-mentioned refractory castable interact with each other at high temperature to produce a chemical reaction, thereby further enhancing the performance of the refractory castable.

[0028] The content of the first aggregate can be 35% to 55%. The first aggregate plays a role as a skeleton in the castable, improving the strength, high temperature performance, and erosion resistance of the castable; when its content is lower than 35%, an effective skeleton structure cannot be formed in the castable, which reduces its strength, affects its high temperature performance and erosion resistance, and the castable is prone to deformation and collapse at high temperatures; when its content is higher than 55%, it will lead to excessive large-particle aggregates, affecting the fluidity of the castable, and its density and uniformity will deteriorate, resulting in an increase in the internal pores of the castable, and a decrease in strength. At the same time, the deterioration of fluidity will affect the construction, and the increase in aggregates will increase the cost. Exemplarily, the content of the first aggregate can be 35%, 40%, 45%, 50%, 55%, etc., and further, the content of the first aggregate can be 40% to 45%. The content of the first aggregate can be 1 to 10 mm.

[0029] The content of lightweight aggregate can be 5% to 15%. The lightweight aggregate reflects the lightweight design of the castable. The lightweight aggregate is used to adjust the density of the castable and improve the thermal insulation performance. When its content is lower than 5%, the lightweight aggregate has a limited effect on the thermal conductivity of the castable. When its content is higher than 15%, the density of the castable is too small and the porosity is too large, resulting in a decrease in its strength, high temperature performance, and corrosion resistance. Exemplarily, the content of the above-mentioned lightweight aggregate can be 5%, 7%, 10%, 12%, 15%, etc. Further, the content of the lightweight aggregate can be 10% to 15%, and the content of the lightweight aggregate can be 1 to 10 mm.

[0030] The content of the powder can be 30% to 40%, so that it can play a filling role in the castable, so that the raw materials can be mixed to form a dense stack, improve the density of the material, and improve its strength, corrosion resistance and other properties; when its content is lower than 30%, it cannot effectively fill the gaps between the aggregates, resulting in a decrease in the density of the castable and a decrease in corrosion resistance. At the same time, too little powder leads to poor fluidity, affecting the molding quality of the castable and reducing its strength; when its content is higher than 40%, it cannot form a reasonable particle grading with the aggregate, resulting in a decrease in strength, and at the same time, the consistency of the castable is increased, affecting the construction, and the drying and sintering time are prolonged, affecting the production efficiency. Exemplarily, the content of the above-mentioned powder can be 30%, 32%, 34%, 36%, 38%, 40%, etc. Further, the content of the powder can be 30% to 35%, and the particle size of the powder can be less than 0.074mm.

[0031] The content of the binder can be 5% to 10%, in order to provide the necessary bonding strength for the castable, so that it can form a solid structure after solidification, ensure its construction performance, such as fluidity, plasticity, water retention, etc., so that the casting quality can reach the best; when its content is lower than 5%, it will affect the construction of the castable, the fluidity will deteriorate, and it will not be able to form an effective bond, resulting in the deterioration of various properties such as strength and corrosion resistance; when its content is higher than 10%, it will cause the castable to over-harden and increase the porosity, which will affect the overall performance of the material, prolong the drying and sintering time, increase energy consumption, and affect production efficiency. Exemplarily, the content of the above-mentioned binder can be 5%, 6%, 7%, 8%, 9%, 10%, etc.

[0032] The content of water reducer can be 0.5% to 1.5% to improve the fluidity of castables and reduce water consumption; when its content is lower than 0.75%, the fluidity of castables will be insufficient, leading to construction difficulties, and the porosity will increase, affecting the density and strength of the material; when its content is higher than 1.5%, the strength of castables will be affected, and water reducer will be difficult to form effective combination at high temperature, while increasing production cost. Exemplarily, the content of the water reducer can be 0.5%, 0.7%, 1.0%, 1.3%, 1.5%, etc.

[0033] The content of refractory fiber can be 1% to 2% to play a toughening role in the castable, improve the toughness, strength and thermal shock stability of the castable; when its content is lower than 1%, the castable is prone to cracks during use, resulting in a decrease in the toughness, strength and thermal shock stability of the castable; when its content is higher than 2%, it will increase the porosity, affect the density of the castable, increase the thermal conductivity, affect its thermal insulation effect, and increase the material cost. Exemplarily, the content of the above refractory fiber can be 1%, 1.5%, 2%, etc.

[0034] In some embodiments, the lightweight aggregate includes at least one of the following: porous kaolinite and porous pyrophyllite.

[0035] In an embodiment of the present application, the lightweight aggregate includes a combination of one or more of the following porous kaolinite and porous pyrophyllite. The Al2O3 mass percentage content in the porous kaolinite is ≥25%, and the SiO2 mass percentage content is ≥50%. The Al2O3 mass percentage content in the porous pyrophyllite is ≥25%, and the SiO2 mass percentage content is ≥50%. Porous kaolinite and porous pyrophyllite can significantly reduce the overall density of the castable due to their porous structure, thereby reducing the weight of the material; the porous structure helps to reduce the thermal conductivity of the material and improve the thermal insulation performance; the porous structure of the lightweight aggregate can absorb and relieve stress to a certain extent, reduce the occurrence of cracks, and thus enhance the crack resistance of the castable.

[0036] In some embodiments, the lightweight aggregate is obtained by impregnating a lightweight aggregate matrix with a resin.

[0037] In some embodiments, the resin includes at least one of the following: phenolic resin, epoxy resin, furan resin.

[0038] In the embodiment of the present application, the lightweight aggregate is obtained by impregnating the lightweight aggregate matrix with resin. The impregnation of the lightweight aggregate increases its weight, avoiding the construction difficulties caused by the floating "segregation" during the construction mixing process, which affects the performance of the castable. During high-temperature use, the impregnated material burns away, which does not affect the thermal insulation performance of the lightweight aggregate; at the same time, the resin impregnation can enhance the internal bonding force of the lightweight aggregate and improve the mechanical strength. Specifically, the lightweight aggregate is obtained by impregnating the lightweight aggregate matrix with resin, including: placing the lightweight aggregate in an impregnation tank and sealing it, turning on the vacuum pump until the residual pressure in the impregnation tank is less than 2500Pa, keeping it at this vacuum for 10 minutes, opening the liquid inlet valve on the impregnation tank to inject the resin, closing the liquid inlet valve when the lightweight aggregate is completely submerged, continuing to vacuum for 10 minutes and then turning off the vacuum pump, opening the air inlet valve on the impregnation tank, making the pressure inside and outside the container balanced and then closing the air inlet valve, turning on the air compressor until the pressure inside the impregnation tank is greater than 0.08Mpa, keeping it at this pressure for 10 minutes and then turning off the air compressor, opening the air inlet valve, making the pressure inside and outside the container balanced, opening the impregnation tank to take out the lightweight aggregate, and drying it for standby use. Exemplarily, the above-mentioned resin can be a combination of one or more of phenolic resin, epoxy resin, and furan resin.

[0039] In some embodiments, the powder includes: high-alumina bauxite powder, aluminum powder and silicon powder.

[0040] In an embodiment of the present application, the powder may include high-alumina bauxite powder, aluminum powder and silicon powder. The high-alumina bauxite powder has high refractoriness and chemical stability, and can improve the high-temperature performance and corrosion resistance of the castable; the aluminum powder can promote the hardening process of the castable due to its high activity and improve the early strength of the castable; the silicon powder has a high specific surface area and activity, which can improve the fluidity and construction performance of the castable, while improving the density and corrosion resistance. The combination of high-alumina bauxite powder and aluminum powder helps to enhance the corrosion resistance of the castable and extend its service life. The powder undergoes a melting reaction at high temperature to generate new compounds, such as aluminum powder and silicon powder reacting to form a more stable mineral phase-mullite, which helps to improve the high-temperature strength and slag resistance of the castable.

[0041] In some embodiments, the weight ratio of the high alumina powder M1, the aluminum powder M2 and the silicon powder M3 is M1:M2:M3 (6-8):(3-4):(6-8).

[0042] In the embodiment of the present application, the weight ratio M1:M2:M3 of high-alumina bauxite powder M1, aluminum powder M2 and silicon powder M3 is (6-8): (3-4): (6-8). This ratio can balance the components and achieve high strength and high temperature resistance of the castable. An appropriate amount of silicon powder can improve the construction performance of the castable, reduce the amount of water or other liquids, thereby reducing the porosity of the castable, helping to improve the density of the castable, and improve its resistance to slag penetration and strength. If the proportion of a component is too high or too low, it may cause uneven performance of the castable, such as insufficient strength or decreased refractoriness. Improper proportions may affect the fluidity and hardening behavior of the castable, leading to problems during construction, such as segregation, precipitation, or too fast or too slow hardening speed. Exemplarily, the above-mentioned M1:M2:M3 can be 2:1:2, 7:3:7, 8:3:8, etc.

[0043] In some embodiments, the first aggregate includes at least one of the following: sintered corundum, high-alumina bauxite, and mullite.

[0044] In the embodiment of the present application, the first aggregate may include at least one of the following: sintered corundum, high-alumina bauxite, and mullite, wherein the mass percentage of Al2O3 in corundum is ≥90%, the mass percentage of Al2O3 in high-alumina bauxite is ≥45%, and the mass percentage of Al2O3 in mullite is ≥70%. Due to the high Al2O3 content of sintered corundum, high-alumina bauxite, mullite, etc., they can provide excellent high temperature resistance and ensure that the castable maintains structural stability at high temperatures; these aggregates have high strength and hardness, play a skeleton role, help improve the strength of the castable and extend its service life; due to the low thermal expansion coefficient of the aggregate, it can reduce the internal stress caused by temperature changes, thereby improving the thermal shock stability of the material. The first aggregate is sintered at high temperature, and phase transformation and recrystallization occur, which enhances the structural stability; for example, corundum will be transformed into α-Al2O3 at high temperature, which has high refractoriness and hardness.

[0045] In some embodiments, the binder includes at least one of the following: silica sol and alumina sol.

[0046] In the embodiment of the present application, the binder can be a combination of one or more of silica sol and alumina sol; at high temperature, the binder silica sol will promote the formation of silicate minerals and enhance the bonding strength of the castable; the alumina sol can promote the formation of alumina and improve the refractoriness and stability of the material.

[0047] In some embodiments, the water reducing agent includes at least one of the following: naphthalene sulfonate formaldehyde condensate, melamine sulfonate formaldehyde condensate, and lignin sulfonate.

[0048] In the embodiment of the present application, the water reducing agent may be a combination of one or more of naphthalene sulfonate formaldehyde condensate, melamine sulfonate formaldehyde condensate, and lignin sulfonate.

[0049] In summary, the above powders and binders form the matrix of the castable at high temperature, and the aggregates are sintered to form polycrystalline particles and bonded to the matrix. The combined effect of the above raw materials ensures that the lightweight thermal insulation refractory castable has good physical properties and chemical stability, can maintain low thermal conductivity and excellent corrosion resistance in high temperature environments, and meet the needs of industrial applications.

[0050] Figure 1 A schematic diagram of a method for preparing a refractory castable provided in an embodiment of the present application; see Figure 1 , a method for preparing a refractory castable comprises: S1, first mixing a first aggregate, a lightweight aggregate with a porous structure, a powder, a water reducing agent and a refractory fiber to obtain a first mixture; S2, second mixing the first mixture with a binder to obtain a second mixture; S3, pouring and vibrating the second mixture, and then curing, demoulding and baking to obtain a finished refractory castable. Specifically, the first aggregate, lightweight aggregate, powder, water reducing agent and refractory fiber are weighed according to the mass percentage, put into a mixer and mixed for 5 to 10 minutes, and then the binder is added, and the stirring is continued for 5 to 10 minutes, and then the pouring and vibrating operation is performed, and the finished product is formed after curing, demoulding and baking.

[0051] In some embodiments, the refractory castable meets the following properties: bulk density <2.0 g / cm 3 , thermal conductivity (average 350℃) <0.8W / mK, compressive strength at 110℃×24h>12MPa, compressive strength at 1500℃×3h>34MPa, thermal shock stability performance 1100℃ water cooling ≥30 times.

[0052] In the embodiment of the present application, the refractory castable is a lightweight heat-insulating refractory castable with good high-temperature performance. Compared with the traditional refractory castable, the volume density of the castable is reduced, the specific heat capacity and thermal conductivity are reduced, so that the heat storage and heat dissipation losses of the refractory lining of the kiln are reduced, the thermal insulation performance is improved, the outer surface temperature of the kiln can be reduced by 30-40°C, the heat transfer can be reduced by 800-900MJ, the temperature drop of molten steel is reduced, the baking efficiency of the furnace lining is improved, and the effect of thermal insulation and energy saving is achieved. At the same time, the weight of the kiln is reduced, the thermal insulation performance is improved, the shell structure of the furnace body is protected from the influence of high temperature, and the service life of industrial kilns and high-temperature equipment is extended. It can play a demonstration role in the industry and bring good economic and social benefits.

[0053] The performance index of this product reaches: volume density <2.0g / cm 3, thermal conductivity (average 350℃) <0.8W / mK, compressive strength at 110℃×24h>12MPa, compressive strength at 1500℃×3h>34MPa, thermal shock stability performance 1100℃ water cooling ≥30 times, it has the advantages of light weight, heat preservation and energy saving, good thermal shock stability, etc., and can be used in working environments with rapid temperature fluctuations.

[0054] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0055] Example 1

[0056] A refractory castable, the raw materials of which include:

[0057] 1) 45% of mullite aggregate with a particle size of 10 to 1 mm;

[0058] 2) 10% porous kaolinite lightweight aggregate with a particle size of 10 to 1 mm;

[0059] 3) 35% of powder with a particle size less than 0.074 mm (mass percentage of high-alumina bauxite powder, aluminum powder and silicon powder 2:1:2);

[0060] 4) Silica sol 8%;

[0061] 5) 1% naphthalenesulfonate formaldehyde condensate;

[0062] 6) Refractory fiber 1%.

[0063] The lightweight aggregate is impregnated, and the impregnation liquid is phenolic resin. The impregnation method is: put the lightweight aggregate into the impregnation tank and seal it, turn on the vacuum pump until the residual pressure in the impregnation tank is 2000Pa, keep it under this vacuum for 10 minutes, open the liquid inlet valve on the impregnation tank to inject the resin, and when the lightweight aggregate is completely submerged, close the liquid inlet valve, continue to vacuum for 10 minutes, then turn off the vacuum pump, open the air inlet valve on the impregnation tank, make the pressure inside and outside the container balanced, then close the air inlet valve, turn on the air compressor until the pressure in the impregnation tank is 0.10Mpa, keep it under this pressure for 10 minutes, then turn off the air compressor, open the air inlet valve, make the pressure inside and outside the container balanced, open the impregnation tank to take out the lightweight aggregate, and dry it for standby use.

[0064] A method for preparing a refractory castable comprises: weighing aggregate, lightweight aggregate, powder, naphthalenesulfonate formaldehyde condensate and refractory fiber according to mass percentage, putting them into a mixer and mixing them for 8 minutes, adding silica sol, continuing to stir for 5 minutes, pouring and vibrating, and forming a finished product after curing, demoulding and baking.

[0065] The tested product performance is: volume density 1.81g / cm 3 The average thermal conductivity at 350℃ is 0.73W / mK, the compressive strength at 110℃×24h is 14.7MPa, the compressive strength at 1500℃×3h is 41.5MPa, and the thermal shock stability performance is 1100℃ water cooling ≥30 times.

[0066] Example 2

[0067] A refractory castable, the raw materials of which include:

[0068] 1) 55% of corundum aggregate with a particle size of 10 to 1 mm;

[0069] 2) 5% of porous pyrophyllite lightweight aggregate with a particle size of 10 to 1 mm;

[0070] 3) 30% of powder with a particle size less than 0.074 mm (mass percentage of high-alumina bauxite powder, aluminum powder and silicon powder 2:1:2);

[0071] 4) Silica sol 8%;

[0072] 5) Melamine sulfonate formaldehyde condensate 1%;

[0073] 6) Refractory fiber 1%.

[0074] Among them, the lightweight aggregate is impregnated, and the impregnation liquid is epoxy resin. The impregnation method is: put the lightweight aggregate into the impregnation tank and seal it, turn on the vacuum pump until the residual pressure in the impregnation tank is 2200Pa, keep it under this vacuum for 10 minutes, open the liquid inlet valve on the impregnation tank to inject the resin, and when the lightweight aggregate is completely submerged, close the liquid inlet valve, continue to vacuum for 10 minutes, then turn off the vacuum pump, open the air inlet valve on the impregnation tank, make the pressure inside and outside the container balanced, then close the air inlet valve, turn on the air compressor until the pressure in the impregnation tank is 0.10Mpa, keep it under this pressure for 10 minutes, then turn off the air compressor, open the air inlet valve, make the pressure inside and outside the container balanced, open the impregnation tank to take out the lightweight aggregate, and dry it for use.

[0075] A method for preparing a refractory castable comprises: weighing aggregate, lightweight aggregate, powder, melamine sulfonate formaldehyde condensate and refractory fiber according to mass percentage, putting them into a mixer and mixing them for 8 minutes, adding silica sol, continuing to stir for 5 minutes, pouring and vibrating, and forming a finished product after curing, demoulding and baking.

[0076] The tested product performance is: volume density 1.98g / cm 3 The average thermal conductivity at 350℃ is 0.80W / mK, the compressive strength at 110℃×24h is 17.6MPa, the compressive strength at 1500℃×3h is 53.9MPa, and the thermal shock stability performance is 1100℃ water cooling ≥30 times.

[0077] Example 3

[0078] A refractory castable, the raw materials of which include:

[0079] 1) 35% aggregate with a particle size of 10 to 1 mm (mass percentage of high alumina and mullite 2:3);

[0080] 2) 15% lightweight aggregate with a particle size of 10 to 1 mm (porous kaolinite and porous pyrophyllite in a mass percentage of 2:3);

[0081] 3) 40% of powder with a particle size less than 0.074 mm (mass percentage of high-alumina bauxite powder, aluminum powder and silicon powder 2:1:2);

[0082] 4) Silica sol 8%;

[0083] 5) 1% lignin sulfonate;

[0084] 6) Refractory fiber 1%.

[0085] Among them, the lightweight aggregate is impregnated, and the impregnation liquid is furan resin. The impregnation method is: put the lightweight aggregate into the impregnation tank and seal it, turn on the vacuum pump until the residual pressure in the impregnation tank is 2300Pa, keep it under this vacuum for 10 minutes, open the liquid inlet valve on the impregnation tank to inject the resin, and when the lightweight aggregate is completely submerged, close the liquid inlet valve, continue to vacuum for 10 minutes, then turn off the vacuum pump, open the air inlet valve on the impregnation tank, make the pressure inside and outside the container balanced, then close the air inlet valve, turn on the air compressor until the pressure in the impregnation tank is 0.09Mpa, keep it under this pressure for 10 minutes, then turn off the air compressor, open the air inlet valve, make the pressure inside and outside the container balanced, open the impregnation tank to take out the lightweight aggregate, and dry it for use.

[0086] A method for preparing a refractory castable comprises: weighing aggregate, lightweight aggregate, powder, lignin sulfonate and refractory fiber according to mass percentage, putting them into a mixer and mixing them for 8 minutes, adding silica sol, continuing to stir for 5 minutes, pouring and vibrating, and forming a finished product after curing, demoulding and baking.

[0087] The tested product performance is: volume density 1.65g / cm 3The average thermal conductivity at 350℃ is 0.62W / mK, the compressive strength at 110℃×24h is 13.7MPa, the compressive strength at 1500℃×3h is 36.8MPa, and the thermal shock stability performance is 1100℃ water cooling ≥30 times.

[0088] Example 4

[0089] A refractory castable, the raw materials of which include:

[0090] 1) Aggregate with a particle size of 10 to 1 mm: 43% (corundum and mullite mass percentage 23:20);

[0091] 2) 10% lightweight aggregate with a particle size of 10 to 1 mm (porous kaolinite and porous pyrophyllite in a mass percentage of 1:1);

[0092] 3) 34% of powder with a particle size less than 0.074 mm (mass percentage of high-alumina bauxite powder, aluminum powder and silicon powder 7:3:7);

[0093] 4) Aluminum sol 10%;

[0094] 5) 1% naphthalenesulfonate formaldehyde condensate;

[0095] 6) Refractory fiber 2%.

[0096] Among them, the lightweight aggregate is impregnated, and the impregnation liquid is phenolic resin. The impregnation method is: put the lightweight aggregate into the impregnation tank and seal it, turn on the vacuum pump until the residual pressure in the impregnation tank is 2200Pa, keep it under this vacuum for 10 minutes, open the liquid inlet valve on the impregnation tank to inject the resin, and when the lightweight aggregate is completely submerged, close the liquid inlet valve, continue to vacuum for 10 minutes, then turn off the vacuum pump, open the air inlet valve on the impregnation tank, make the pressure inside and outside the container balanced, then close the air inlet valve, turn on the air compressor until the pressure in the impregnation tank is 0.08Mpa, keep it under this pressure for 10 minutes, then turn off the air compressor, open the air inlet valve, make the pressure inside and outside the container balanced, open the impregnation tank to take out the lightweight aggregate, and dry it for use.

[0097] A method for preparing a refractory castable comprises: weighing aggregate, lightweight aggregate, powder, naphthalenesulfonate formaldehyde condensate and refractory fiber according to mass percentage, putting them into a mixer and mixing them for 8 minutes, adding aluminum sol, continuing to stir for 5 minutes, pouring and vibrating, and forming a finished product after curing, demoulding and baking.

[0098] The tested product performance is: volume density 1.78g / cm 3 The average thermal conductivity at 350℃ is 0.75W / mK, the compressive strength at 110℃×24h is 15.3MPa, the compressive strength at 1500℃×3h is 45.1MPa, and the thermal shock stability performance is 1100℃ water cooling ≥30 times.

[0099] Comparative Example 1

[0100] A refractory castable, the raw materials of which include:

[0101] 1) 45% of mullite aggregate with a particle size of 10 to 1 mm;

[0102] 2) 10% porous mullite with a particle size of 10 to 1 mm;

[0103] 3) 35% of powder with a particle size less than 0.074 mm (mass percentage of high-alumina bauxite powder, aluminum powder and silicon powder 2:1:2);

[0104] 4) Silica sol 8%;

[0105] 5) 1% naphthalenesulfonate formaldehyde condensate;

[0106] 6) Refractory fiber 1%.

[0107] A preparation method of a refractory castable comprises: weighing aggregate, porous mullite, powder, naphthalenesulfonate formaldehyde condensate and refractory fiber according to mass percentage, putting them into a mixer and mixing them for 8 minutes, adding silica sol, continuing to stir for 5 minutes, pouring and vibrating, and forming a finished product after curing, demoulding and baking.

[0108] The tested product performance is: volume density 2.03g / cm 3 , average thermal conductivity at 350℃ is 1.17W / mK, compressive strength at 110℃×24h is 15.8MPa, compressive strength at 1500℃×3h is 41.9MPa, thermal shock stability is 1100℃ water cooling ≥30 times. .Comparative Example 2

[0109] A refractory castable, the raw materials of which include:

[0110] 7) 45% of mullite aggregate with a particle size of 10 to 1 mm;

[0111] 8) 10% of porous kaolinite lightweight aggregate with a particle size of 10 to 1 mm;

[0112] 9) 35% of powder with a particle size less than 0.074 mm (mass percentage of high-alumina bauxite powder, aluminum powder and silicon powder 2:1:2);

[0113] 10) Silica sol 8%;

[0114] 11) 1% naphthalenesulfonate formaldehyde condensate;

[0115] 12) Refractory fiber 1%.

[0116] A method for preparing a refractory castable comprises: weighing aggregate, lightweight aggregate, powder, naphthalenesulfonate formaldehyde condensate and refractory fiber according to mass percentage, putting them into a mixer and mixing them for 8 minutes, adding silica sol, continuing to stir for 5 minutes, pouring and vibrating, and forming a finished product after curing, demoulding and baking.

[0117] The tested product performance is: volume density 1.95g / cm 3 The average thermal conductivity at 350℃ is 0.94W / mK, the compressive strength at 110℃×24h is 14.5MPa, the compressive strength at 1500℃×3h is 39.8MPa, and the thermal shock stability performance is 1100℃ water cooling ≥30 times.

[0118] The refractory castables obtained in Examples 1 to 4 have low bulk density and excellent thermal insulation performance, while maintaining excellent compressive strength and thermal shock stability, and have excellent comprehensive performance. In Comparative Example 1, the porous lightweight aggregate of the present patent application is not used, and the bulk density and average thermal conductivity at 350°C are higher than those of Example 1; and in Comparative Example 2, although the porous lightweight aggregate of the present application is used, it is not impregnated, and the bulk density and average thermal conductivity at 350°C are higher than those of Example 1, and due to the lack of impregnation, the lightweight aggregate floats, resulting in low compressive strength.

[0119] One or more technical solutions in the embodiments of the present application also have at least the following technical effects or advantages:

[0120] (1) The use of lightweight aggregates, such as porous kaolinite and porous pyrophyllite, has a lower density than traditional dense aggregates, which helps to reduce the density of the overall castable, thereby reducing the heat capacity and thermal conductivity.

[0121] (2) Impregnation treatment of lightweight aggregate. Lightweight aggregate can be impregnated with resin to enhance its dispersibility and compatibility in the castable, reduce the floating phenomenon during mixing, and ensure the uniformity and construction performance of the castable.

[0122] (3) Optimizing the ratio of powders: using high-alumina bauxite powder, aluminum powder, silicon powder, etc. as powders. The particle size of these powders is less than 0.074 mm, which helps to improve the fluidity of the castable while ensuring the density of the material.

[0123] (4) Application of binders and water reducers. The use of binders and water reducers helps to improve the rheological properties of castables and reduce the amount of water, further improving the density and strength of the material.

[0124] (5) Addition of refractory fiber: The addition of refractory fiber can further improve the thermal insulation performance of the castable, while also playing a toughening role to ensure the high-temperature structural strength of the castable.

[0125] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A refractory castable, characterized in that: The raw materials of the refractory castable include: a first aggregate, a lightweight aggregate with a porous structure, a powder, a binder, a water reducing agent and a refractory fiber; wherein, by mass fraction, The content of the first aggregate is 35% to 55%, the content of the lightweight aggregate is 5% to 15%, the content of the powder is 30% to 40%, the content of the binder is 5% to 10%, the content of the water reducer is 0.5% to 1.5%, and the content of the refractory fiber is 1% to 2%.

2. The refractory castable according to claim 1, characterized in that: The lightweight aggregate includes at least one of the following: porous kaolinite and porous pyrophyllite.

3. The refractory castable according to claim 1, characterized in that: The lightweight aggregate is obtained by impregnating a lightweight aggregate matrix with resin.

4. The refractory castable according to claim 3, characterized in that: The resin includes at least one of the following: phenolic resin, epoxy resin, and furan resin.

5. The refractory castable according to claim 1, characterized in that: The powder material includes: high-alumina bauxite powder, aluminum powder and silicon powder.

6. The refractory castable according to claim 5, characterized in that: The weight ratio of the high-alumina bauxite powder M1, the aluminum powder M2 and the silicon powder M3 is M1:M2:M3 (6-8):(3-4):(6-8).

7. The refractory castable according to claim 1, characterized in that: The first aggregate includes at least one of the following: sintered corundum, high-alumina bauxite, and mullite.

8. The refractory castable according to claim 1, characterized in that: The binder includes at least one of the following: silica sol and aluminum sol.

9. The refractory castable according to claim 1, characterized in that: The water reducing agent comprises at least one of the following: naphthalene sulfonate formaldehyde condensate, melamine sulfonate formaldehyde condensate, and lignin sulfonate.

10. The refractory castable according to any one of claims 1 to 9, characterized in that: The refractory castable meets the following properties: bulk density <2.0g / cm 3 , thermal conductivity (average 350℃) <0.8W / mK, compressive strength at 110℃×24h>12MPa, compressive strength at 1500℃×3h>34MPa, thermal shock stability performance 1100℃ water cooling ≥30 times.

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