High-temperature fire-resistant heat-insulating carbon fiber composite material and preparation method thereof

Abstract

The invention discloses a high-temperature fire-resistant heat-insulation carbon fiber composite material which comprises the following components in parts by weight: 35-50 parts of wollastonite-feldspar composite powder, 25-35 parts of modified porous mullite aggregate, 12-20 parts of calcium aluminate cement, 2-8 parts of modified short carbon fibers, 1.5-2.5 parts of sodium dodecyl benzene sulfonate and 1-2 parts of sodium tripolyphosphate. The preparation method comprises the following steps: S1, weighing the wollastonite-feldspar composite powder, the modified porous mullite aggregate, the calcium aluminate cement and the modified short carbon fibers in proportion, and carrying out dry mixing; s2, adding water into sodium dodecyl benzene sulfonate and sodium tripolyphosphate, and stirring to obtain an auxiliary agent aqueous solution; s3, adding the auxiliary agent aqueous solution into the dry powder mixture, and stirring; s4, transferring the slurry into a mold for hydraulic forming; s5, the formed blank is subjected to curing, demolding, drying, high-temperature sintering and cooling, and the high-temperature fire-resistant heat-insulation carbon fiber composite material is obtained. The fire-resistant and heat-insulating carbon fiber composite material produced by the invention can improve the high temperature resistance and compression strength.

Description

Technical Field

[0001] This invention relates to the field of refractory materials technology, and in particular to a high-temperature refractory and heat-insulating carbon fiber composite material and its preparation method. Background Technology

[0002] High-temperature refractory insulation materials are indispensable key materials in industrial production, building kilns, metallurgy, and chemical industries. Their performance directly affects the operating efficiency, service life, and safety of high-temperature equipment. With the continuous upgrading of industrial technology, the requirements for refractory insulation materials under high-temperature conditions are becoming increasingly stringent. Refractory insulation materials not only need to have excellent high-temperature resistance, but also need to have good thermal insulation, mechanical strength, and thermal shock resistance to adapt to complex working conditions of repeated heating and cooling.

[0003] Currently, there are many types of high-temperature refractory and heat-insulating materials on the market, mainly including traditional refractory bricks, ceramic fiber materials, lightweight refractory castables, and carbon fiber reinforced composites. While traditional refractory bricks have good high-temperature resistance, they suffer from drawbacks such as high density, poor insulation, and insufficient thermal shock resistance, making them prone to cracking and breakage during thermal cycles. Ceramic fiber materials offer excellent insulation, but their low mechanical strength makes them susceptible to pulverization and failure under prolonged high-temperature conditions, resulting in a short service life. Lightweight refractory castables possess certain refractoriness and insulation properties, but their low strength after molding and tendency to shrink during sintering affect construction quality and operational stability. Carbon fiber refractory composites possess high strength, thermal shock resistance, and corrosion resistance, effectively improving the mechanical properties and crack resistance of refractory materials. However, the low surface activity of carbon fibers and weak interfacial bonding with the matrix material limit their application in composite materials.

[0004] Therefore, this application provides a high-temperature refractory and heat-insulating carbon fiber composite material and its preparation method to solve the problems of weak compressive strength of carbon fiber bonded to refractory matrix and insufficient high-temperature resistance of lightweight aggregate, thereby enhancing high-temperature resistance and improving compressive strength. Summary of the Invention

[0005] The purpose of this invention is to provide a high-temperature refractory and heat-insulating carbon fiber composite material and its preparation method, so as to solve the problems of weak compressive strength of carbon fiber combined with refractory matrix and insufficient high-temperature resistance of lightweight aggregate, thereby enhancing high-temperature resistance and improving compressive strength.

[0006] In a first aspect, the present invention provides a high-temperature refractory and heat-insulating carbon fiber composite material, comprising the following components in parts by weight: 35-50 parts of wollastonite-feldspar composite powder, 25-35 parts of modified porous mullite aggregate, 12-20 parts of calcium aluminate cement, 2-8 parts of modified short-cut carbon fiber, 1.5-2.5 parts of sodium dodecylbenzenesulfonate, and 1-2 parts of sodium tripolyphosphate.

[0007] As a preferred technical solution of the present invention, the wollastonite-feldspar composite powder is prepared by the following method: (1) Wollastonite and potassium feldspar are placed in a planetary ball mill at a mass ratio of 1:0.6 to 0.8 and ball milled at a speed of 250 to 350 r / min for 4 to 6 hours, and then passed through a 200-mesh sieve to obtain a mixed powder; (2) The mixed powder is placed in a box-type resistance furnace and heated at 900 to 950°C for 2 to 3 hours, and then cooled to obtain wollastonite-feldspar composite powder.

[0008] As a preferred technical solution of the present invention, the modified porous mullite aggregate is prepared by the following method: porous mullite aggregate raw material with Al2O3 content ≥75% and particle size of 50-200μm is immersed in a silica sol solution with a concentration of 5-10%, stirred for 30-50 minutes, then taken out and placed in an electric heating constant temperature drying oven, and dried at 75-85℃ for 2-3 hours to obtain modified porous mullite aggregate.

[0009] As a preferred embodiment of the present invention, the calcium aluminate cement is CA-50 type industrial grade calcium aluminate cement, wherein the Al2O3 content is ≥50%.

[0010] As a preferred technical solution of the present invention, the modified short-cut carbon fiber is prepared by the following method: (1) the short-cut carbon fiber is placed in a muffle furnace and calcined at 400-450°C for 20-30 minutes, and after cooling, oxidized short-cut carbon fiber is obtained; (2) the oxidized short-cut carbon fiber is placed in a high-speed mixer, and silane coupling agent KH-560 is added to the high-speed mixer according to the mass ratio of oxidized short-cut carbon fiber to silane coupling agent KH-560 of 50-70:1. The speed of the high-speed mixer is set to 1300-1500 r / min, and dry-mixed for 6-10 min to obtain modified short-cut carbon fiber.

[0011] As a preferred embodiment of the present invention, the sodium dodecylbenzenesulfonate is pretreated by the following method: the sodium dodecylbenzenesulfonate is placed in an electric thermostatic drying oven and dried at 60-80°C for 1-2 hours. After drying, it is cooled to room temperature and passed through a 200-mesh sieve. The sieved sodium dodecylbenzenesulfonate is then transferred to a brown sealed bottle for later use.

[0012] As a preferred embodiment of the present invention, the sodium tripolyphosphate is industrial grade sodium tripolyphosphate with a purity ≥98% and a water solubility ≥95g / 100mL at room temperature.

[0013] Secondly, the present invention also provides a method for preparing a high-temperature refractory and heat-insulating carbon fiber composite material, comprising the following steps:

[0014] S1. Weigh out wollastonite-feldspar composite powder, modified porous mullite aggregate, calcium aluminate cement and modified short-cut carbon fiber according to the proportion, put them into a high-speed mixer, set the speed to 800-1000 r / min, dry mix for 8-12 minutes to obtain a dry powder mixture.

[0015] S2. Weigh out deionized water and place it in a mixing tank according to the mass ratio of dry powder mixture to water of 20:5-7. Add sodium dodecylbenzenesulfonate and sodium tripolyphosphate to the deionized water in proportion. Set the speed of the mixing tank to 500-600 r / min and stir for 15-20 minutes to obtain an aqueous solution of the additives.

[0016] S3. Adjust the speed of the high-speed mixer to 400-500 r / min, and slowly add the aqueous solution of the additive to the dry powder mixture through the feed inlet at a rate of 5-10 L / h. After the addition is complete, continue stirring for 20-30 minutes to obtain the slurry.

[0017] S4. Quickly transfer the slurry into the customized mold, use a scraper to smooth the surface of the slurry, send the smoothed mold into the hydraulic molding machine, apply a pressure of 15-25MPa, hold the pressure for 3-5 minutes, and obtain the molded blank.

[0018] S5. Place the molded blank along with the mold into a constant temperature and humidity curing chamber, set the curing temperature to 20-28℃ and the relative humidity to 70-80%, and cure for 20-40 hours. Then, place it into a hydraulic demolding machine for demolding. After demolding, place it into an electric heating constant temperature drying oven for drying. Slowly raise the temperature to 110℃ at a rate of 5℃ per hour and hold it at 110℃ for 3-5 hours. After drying, place it into a high temperature sintering furnace. Under a nitrogen atmosphere, raise the temperature to 1100-1200℃ at a rate of 3-5℃ per minute and sinter at this temperature for 2-4 hours. After sintering, cool it to room temperature and remove it to obtain the finished high temperature refractory and heat-insulating carbon fiber composite material.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. This invention utilizes wollastonite-feldspar composite powder as a ceramic matrix in high-temperature refractory and heat-insulating carbon fiber composites, providing excellent high-temperature stability and a certain level of mechanical strength. Wollastonite possesses a unique needle-like or fibrous crystal structure, which remains relatively stable at high temperatures, resisting decomposition or deformation, thus providing high-temperature structural support for the composite material. Potassium feldspar can adjust the coefficient of thermal expansion of the composite material; its crystal structure's expansion or contraction during temperature changes coordinates with wollastonite, reducing the overall coefficient of thermal expansion of the composite material. After ball milling and high-temperature treatment, wollastonite and potassium feldspar achieve synergistic performance optimization, jointly enhancing the high-temperature stability and mechanical strength of the high-temperature refractory and heat-insulating carbon fiber composite material.

[0021] 2. This invention utilizes modified porous mullite aggregate as a lightweight insulating aggregate in high-temperature refractory and heat-insulating carbon fiber composites. This enhances high-temperature resistance and material strength, while its porous structure helps improve insulation performance and reduce heat transfer efficiency. Porous mullite aggregate itself possesses high strength and excellent high-temperature resistance; its crystal structure remains stable at high temperatures. After silica sol soaking, stirring, and drying, the silica sol fills the pores of the aggregate, forming a silicon-aluminum-oxygen composite structure at high temperatures, further enhancing the aggregate's strength and bonding with the matrix material. Simultaneously, the air filling the porous structure acts as an excellent insulating medium, effectively preventing heat conduction, thereby improving the insulation performance of the high-temperature refractory and heat-insulating carbon fiber composite.

[0022] 3. This invention incorporates modified short-cut carbon fibers into high-temperature refractory and heat-insulating carbon fiber composites, enhancing thermal shock resistance and reducing crack propagation and material damage caused by thermal shock. After calcination and oxidation treatment, the active groups formed on the surface of the short-cut carbon fibers increase the surface roughness and chemical activity. Further treatment with a silane coupling agent causes hydrolysis and condensation reactions on the fiber surface, forming an organic-inorganic hybrid film. This film can chemically bond with the inorganic components in the matrix material and also form good physical adsorption and chemical bonding with the carbon fiber surface, thus greatly enhancing the interfacial bonding force between the carbon fiber and the matrix material. When the high-temperature refractory and heat-insulating carbon fiber composite is subjected to external forces or thermal shock, the carbon fibers can effectively transfer and disperse stress, preventing crack propagation and improving the mechanical properties and thermal shock resistance of the high-temperature refractory and heat-insulating carbon fiber composite. Attached Figure Description

[0023] Figure 1 This is a flowchart of the preparation method of the high-temperature refractory and heat-insulating carbon fiber composite material of the present invention. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of the phrase "embodiment" in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0026] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0027] like Figure 1 As shown, a method for preparing a high-temperature refractory and heat-insulating carbon fiber composite material includes the following steps:

[0028] S1. Weigh out wollastonite-feldspar composite powder, modified porous mullite aggregate, calcium aluminate cement and modified short-cut carbon fiber according to the proportion, put them into a high-speed mixer and dry mix to obtain a dry powder mixture.

[0029] S2. Weigh out deionized water according to the proportion and place it in a mixing tank. Add sodium dodecylbenzenesulfonate and sodium tripolyphosphate, and stir to obtain an aqueous solution of the additives.

[0030] S3. Add the aqueous solution of the additive to the dry powder mixture dropwise, and continue stirring after the addition is complete to obtain a slurry.

[0031] S4. Quickly transfer the slurry into the mold, scrape the surface of the slurry, and then send it into the hydraulic forming machine to maintain pressure and obtain the formed blank.

[0032] S5. Place the molded blank into a constant temperature and humidity curing chamber, and after curing, place it into a hydraulic demolding machine for demolding. After demolding, dry it first, and then sinter it at high temperature. After sintering, cool it to room temperature and take it out to obtain the finished high temperature refractory and heat-insulating carbon fiber composite material.

[0033] All raw materials used in this invention are commercially available.

[0034] Example 1:

[0035] A high-temperature refractory and heat-insulating carbon fiber composite material comprises the following components in parts by weight: 35 parts of wollastonite-feldspar composite powder, 25 parts of modified porous mullite aggregate, 12 parts of calcium aluminate cement, 2 parts of modified short-cut carbon fiber, 1.5 parts of sodium dodecylbenzene sulfonate, and 1 part of sodium tripolyphosphate.

[0036] The wollastonite-feldspar composite powder was prepared by the following method: (1) Wollastonite and potassium feldspar were placed in a planetary ball mill at a mass ratio of 1:0.6 and ball milled at a speed of 250 r / min for 6 hours. The mixture was then passed through a 200-mesh sieve to obtain a mixed powder. (2) The mixed powder was placed in a box-type resistance furnace and heated at 900°C for 3 hours. After cooling, the wollastonite-feldspar composite powder was obtained.

[0037] Modified porous mullite aggregate is prepared by the following method: porous mullite aggregate raw material with Al2O3 content ≥75% and particle size of 50-200μm is immersed in a 5% silica sol solution, stirred for 30 minutes, then taken out and placed in an electric heating constant temperature drying oven, and dried at 75℃ for 3 hours to obtain modified porous mullite aggregate.

[0038] The calcium aluminate cement is CA-50 type industrial grade calcium aluminate cement, in which the Al2O3 content is ≥50%.

[0039] Modified chopped carbon fibers were prepared by the following method: (1) The chopped carbon fibers were placed in a muffle furnace and calcined at 400°C for 30 minutes. After cooling, oxidized chopped carbon fibers were obtained; (2) The oxidized chopped carbon fibers were placed in a high-speed mixer. The silane coupling agent KH-560 was added to the high-speed mixer at a mass ratio of 50:1 between the oxidized chopped carbon fibers and the silane coupling agent KH-560. The speed of the high-speed mixer was set to 1300 r / min. The mixture was dry-mixed for 10 minutes to obtain modified chopped carbon fibers.

[0040] Sodium dodecylbenzenesulfonate was pretreated using the following method: Sodium dodecylbenzenesulfonate was placed in an electric thermostatic drying oven and dried at 60°C for 2 hours. After drying, it was cooled to room temperature and passed through a 200-mesh sieve. The sieved sodium dodecylbenzenesulfonate was then transferred to a brown sealed bottle for later use.

[0041] The sodium tripolyphosphate used is industrial grade sodium tripolyphosphate with a purity ≥98% and a water solubility of ≥95g / 100mL at room temperature.

[0042] A method for preparing a high-temperature refractory and heat-insulating carbon fiber composite material includes the following steps:

[0043] S1. Weigh out wollastonite-feldspar composite powder, modified porous mullite aggregate, calcium aluminate cement and modified short-cut carbon fiber according to the proportion, put them into a high-speed mixer, set the speed to 800 r / min, dry mix for 12 minutes to obtain a dry powder mixture.

[0044] S2. Weigh out deionized water and place it in a mixing tank according to the mass ratio of dry powder mixture to water of 20:5. Add sodium dodecylbenzenesulfonate and sodium tripolyphosphate to the deionized water in proportion. Set the speed of the mixing tank to 500 r / min and stir for 20 minutes to obtain an aqueous solution of the additives.

[0045] S3. Adjust the speed of the high-speed mixer to 400 r / min, and slowly add the aqueous solution of the additive to the dry powder mixture through the feed port at a dropping rate of 5 L / h. After the dropping is completed, continue stirring for 30 minutes to obtain the slurry.

[0046] S4. Quickly transfer the slurry into the customized mold, use a scraper to smooth the surface of the slurry, send the smoothed mold into the hydraulic forming machine, apply a pressure of 15MPa, hold the pressure for 5 minutes, and obtain the molded blank.

[0047] S5. Place the molded blank along with the mold into a constant temperature and humidity curing chamber, set the curing temperature to 20℃ and the relative humidity to 70%, and cure for 40 hours. Then, place it into a hydraulic demolding machine for demolding. After demolding, place it into an electric heating constant temperature drying oven for drying. The temperature is slowly increased to 110℃ at a rate of 5℃ per hour and held at 110℃ for 3 hours. After drying, place it into a high temperature sintering furnace. Under a nitrogen atmosphere, the temperature is increased to 1100℃ at a rate of 3℃ per minute and sintered at this temperature for 4 hours. After sintering, cool to room temperature and remove to obtain the finished high temperature refractory and heat-insulating carbon fiber composite material.

[0048] Example 2:

[0049] A high-temperature refractory and heat-insulating carbon fiber composite material comprises the following components in parts by weight: 42 parts of wollastonite-feldspar composite powder, 30 parts of modified porous mullite aggregate, 16 parts of calcium aluminate cement, 5 parts of modified short-cut carbon fiber, 2 parts of sodium dodecylbenzene sulfonate, and 1.5 parts of sodium tripolyphosphate.

[0050] The wollastonite-feldspar composite powder was prepared by the following method: (1) Wollastonite and potassium feldspar were placed in a planetary ball mill at a mass ratio of 1:0.7 and ball milled at a speed of 300 r / min for 5 hours. The mixture was then passed through a 200-mesh sieve to obtain a mixed powder. (2) The mixed powder was placed in a box-type resistance furnace and heated at 925°C for 2.5 hours. After cooling, the wollastonite-feldspar composite powder was obtained.

[0051] Modified porous mullite aggregate was prepared by the following method: porous mullite aggregate raw material with Al2O3 content ≥75% and particle size of 50-200μm was immersed in an 8% silica sol solution, stirred for 40 minutes, then removed and placed in an electric heating constant temperature drying oven, and dried at 80℃ for 2.5 hours to obtain modified porous mullite aggregate.

[0052] The calcium aluminate cement is CA-50 type industrial grade calcium aluminate cement, in which the Al2O3 content is ≥50%.

[0053] Modified chopped carbon fibers were prepared by the following method: (1) The chopped carbon fibers were placed in a muffle furnace and calcined at 425°C for 25 minutes. After cooling, oxidized chopped carbon fibers were obtained; (2) The oxidized chopped carbon fibers were placed in a high-speed mixer. The silane coupling agent KH-560 was added to the high-speed mixer according to the mass ratio of oxidized chopped carbon fibers to silane coupling agent KH-560 of 60:1. The speed of the high-speed mixer was set to 1400 r / min and dry-mixed for 8 minutes to obtain modified chopped carbon fibers.

[0054] Sodium dodecylbenzenesulfonate was pretreated using the following method: Sodium dodecylbenzenesulfonate was placed in an electric thermostatic drying oven and dried at 70°C for 1.5 hours. After drying, it was cooled to room temperature and passed through a 200-mesh sieve. The sieved sodium dodecylbenzenesulfonate was then transferred to a brown sealed bottle for later use.

[0055] The sodium tripolyphosphate used is industrial grade sodium tripolyphosphate with a purity ≥98% and a water solubility of ≥95g / 100mL at room temperature.

[0056] A method for preparing a high-temperature refractory and heat-insulating carbon fiber composite material includes the following steps:

[0057] S1. Weigh out wollastonite-feldspar composite powder, modified porous mullite aggregate, calcium aluminate cement and modified short-cut carbon fiber according to the proportion, put them into a high-speed mixer, set the speed to 900 r / min, dry mix for 10 minutes to obtain a dry powder mixture.

[0058] S2. Weigh out deionized water and place it in a mixing tank according to the mass ratio of dry powder mixture to water of 20:6. Add sodium dodecylbenzenesulfonate and sodium tripolyphosphate to the deionized water in proportion. Set the mixing tank speed to 550 r / min and stir for 18 minutes to obtain an aqueous solution of the additives.

[0059] S3. Adjust the speed of the high-speed mixer to 450 r / min, and slowly add the aqueous solution of the additive to the dry powder mixture through the feed inlet at a rate of 8 L / h. After the addition is complete, continue stirring for 25 minutes to obtain the slurry.

[0060] S4. Quickly transfer the slurry into the customized mold, use a scraper to smooth the surface of the slurry, send the smoothed mold into the hydraulic molding machine, apply a pressure of 20MPa, hold the pressure for 4 minutes, and obtain the molded blank.

[0061] S5. Place the molded blank together with the mold into a constant temperature and humidity curing chamber, set the curing temperature to 24℃ and the relative humidity to 75%, and cure for 30 hours. Then place it into a hydraulic demolding machine for demolding. After demolding, place it into an electric heating constant temperature drying oven for drying. The temperature is slowly increased to 110℃ at a rate of 5℃ per hour and held at 110℃ for 4 hours. After drying, place it into a high temperature sintering furnace. Under a nitrogen atmosphere, the temperature is increased to 1150℃ at a rate of 4℃ per minute and sintered at this temperature for 3 hours. After sintering, cool to room temperature and remove to obtain the finished high temperature refractory heat-insulating carbon fiber composite material.

[0062] Example 3:

[0063] A high-temperature refractory and heat-insulating carbon fiber composite material comprises the following components in parts by weight: 50 parts of wollastonite-feldspar composite powder, 35 parts of modified porous mullite aggregate, 20 parts of calcium aluminate cement, 8 parts of modified short-cut carbon fiber, 2.5 parts of sodium dodecylbenzene sulfonate, and 2 parts of sodium tripolyphosphate.

[0064] The wollastonite-feldspar composite powder was prepared by the following method: (1) Wollastonite and potassium feldspar were placed in a planetary ball mill at a mass ratio of 1:0.8 and ball milled at a speed of 350 r / min for 4 hours. The mixture was then passed through a 200-mesh sieve to obtain a mixed powder. (2) The mixed powder was placed in a box-type resistance furnace and heated at 950°C for 2 hours. After cooling, the wollastonite-feldspar composite powder was obtained.

[0065] Modified porous mullite aggregate is prepared by the following method: porous mullite aggregate raw material with Al2O3 content ≥75% and particle size of 50-200μm is immersed in a 10% silica sol solution, stirred for 50 minutes, then taken out and placed in an electric heating constant temperature drying oven, and dried at 85℃ for 2 hours to obtain modified porous mullite aggregate.

[0066] The calcium aluminate cement is CA-50 type industrial grade calcium aluminate cement, in which the Al2O3 content is ≥50%.

[0067] Modified chopped carbon fibers were prepared by the following method: (1) The chopped carbon fibers were placed in a muffle furnace and calcined at 450°C for 20 minutes. After cooling, oxidized chopped carbon fibers were obtained. (2) The oxidized chopped carbon fibers were placed in a high-speed mixer. The silane coupling agent KH-560 was added to the high-speed mixer at a mass ratio of 70:1 between the oxidized chopped carbon fibers and the silane coupling agent KH-560. The speed of the high-speed mixer was set to 1500 r / min and the mixture was dry-mixed for 6 minutes to obtain modified chopped carbon fibers.

[0068] Sodium dodecylbenzenesulfonate was pretreated using the following method: Sodium dodecylbenzenesulfonate was placed in an electric thermostatic drying oven and dried at 80°C for 1 hour. After drying, it was cooled to room temperature and passed through a 200-mesh sieve. The sieved sodium dodecylbenzenesulfonate was then transferred to a brown sealed bottle for later use.

[0069] The sodium tripolyphosphate used is industrial grade sodium tripolyphosphate with a purity ≥98% and a water solubility of ≥95g / 100mL at room temperature.

[0070] A method for preparing a high-temperature refractory and heat-insulating carbon fiber composite material includes the following steps:

[0071] S1. Weigh out wollastonite-feldspar composite powder, modified porous mullite aggregate, calcium aluminate cement and modified short-cut carbon fiber according to the proportion, put them into a high-speed mixer, set the speed to 1000 r / min, dry mix for 8 minutes to obtain a dry powder mixture.

[0072] S2. Weigh out deionized water and place it in a mixing tank according to the mass ratio of dry powder mixture to water of 20:7. Add sodium dodecylbenzenesulfonate and sodium tripolyphosphate to the deionized water in proportion. Set the speed of the mixing tank to 600 r / min and stir for 15 minutes to obtain an aqueous solution of the additives.

[0073] S3. Adjust the speed of the high-speed mixer to 500 r / min, and slowly add the aqueous solution of the additive to the dry powder mixture through the feed port at a dropping rate of 10 L / h. After the dropping is completed, continue stirring for 20 minutes to obtain the slurry.

[0074] S4. Quickly transfer the slurry into the customized mold, use a scraper to smooth the surface of the slurry, send the smoothed mold into the hydraulic forming machine, apply a pressure of 25MPa, hold the pressure for 3 minutes, and obtain the molded blank.

[0075] S5. Place the molded blank together with the mold into a constant temperature and humidity curing chamber, set the curing temperature to 28℃ and the relative humidity to 80%, and after curing for 20 hours, place it into a hydraulic demolding machine for demolding; after demolding, place it into an electric heating constant temperature drying oven for drying, slowly raise the temperature to 110℃ at a rate of 5℃ per hour, and keep it at 110℃ for 5 hours; after drying, place it into a high temperature sintering furnace, raise the temperature to 1200℃ at a rate of 5℃ per minute under a nitrogen atmosphere, and sinter at this temperature for 2 hours. After sintering, cool to room temperature and take it out to obtain the finished high temperature refractory heat-insulating carbon fiber composite material.

[0076] Comparative Example 1:

[0077] The difference from Example 2 is that a single wollastonite is used instead of the wollastonite-feldspar composite powder.

[0078] Comparative Example 2:

[0079] The difference from Example 2 is that the porous mullite aggregate is added directly without modification.

[0080] Comparative Example 3:

[0081] The difference from Example 2 is that the short-cut carbon fibers are added directly without modification.

[0082] The high-temperature refractory and heat-insulating carbon fiber composite materials produced in Examples 1, 2, and 3 and Comparative Examples 1, 2, and 3 were tested.

[0083] The high-temperature refractory and heat-insulating carbon fiber composites produced in Examples 1, 2, and 3 and Comparative Examples 1, 2, and 3 were tested for room temperature compressive strength using GB / T 5072-2023 "Test Method for Room Temperature Compressive Strength of Refractory Materials" and for high temperature compressive strength using GB / T 34218-2025 "Test Method for High Temperature Compressive Strength of Refractory Materials". The results are shown in Table 1.

[0084] Table 1: Room Temperature Compressive Strength and High Temperature Compressive Strength of High Temperature Resistant and Thermally Insulating Carbon Fiber Composites

[0085] As shown in Table 1, the high-temperature refractory and heat-insulating carbon fiber composite materials produced in Examples 1, 2, and 3 have higher room temperature compressive strength and high temperature compressive strength, while the high-temperature refractory and heat-insulating carbon fiber composite materials produced in Comparative Examples 1, 2, and 3 have lower room temperature compressive strength and high temperature compressive strength.

[0086] The high-temperature refractory and heat-insulating carbon fiber composites produced in Examples 1, 2, and 3 and Comparative Examples 1, 2, and 3 were tested for their temperature resistance limits using GB / T 7322-2017 "Test Method for Refractoriness of Refractory Materials". The results are shown in Table 2.

[0087] Table 2: Temperature Resistance Limits of High-Temperature Resistant and Heat-Insulating Carbon Fiber Composite Materials

[0088] As shown in Table 2, the high-temperature refractory and heat-insulating carbon fiber composite materials produced in Examples 1, 2, and 3 have higher temperature resistance limits, while the high-temperature refractory and heat-insulating carbon fiber composite materials produced in Comparative Examples 1, 2, and 3 have lower temperature resistance limits.

[0089] In summary, the high-temperature refractory and heat-insulating carbon fiber composite material produced by this invention can solve the problems of weak compressive strength of the bond between carbon fiber and refractory matrix and insufficient high-temperature resistance of lightweight aggregate, thereby enhancing high-temperature resistance and improving compressive strength.

[0090] The above are merely specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions, or modifications made based on the present invention to solve essentially the same technical problems and achieve essentially the same technical effects are all covered within the protection scope of the present invention.

Claims

1. A high-temperature refractory and heat-insulating carbon fiber composite material, characterized in that, The composition includes the following components in parts by weight: 35-50 parts of wollastonite-feldspar composite powder, 25-35 parts of modified porous mullite aggregate, 12-20 parts of calcium aluminate cement, 2-8 parts of modified short-cut carbon fiber, 1.5-2.5 parts of sodium dodecylbenzene sulfonate, and 1-2 parts of sodium tripolyphosphate.

2. The high-temperature refractory and heat-insulating carbon fiber composite material according to claim 1, characterized in that, The wollastonite-feldspar composite powder is prepared by the following method: (1) Wollastonite and potassium feldspar are placed in a planetary ball mill at a mass ratio of 1:0.6 to 0.8 and ball milled at a speed of 250 to 350 r / min for 4 to 6 hours. The mixture is then passed through a 200-mesh sieve to obtain a mixed powder; (2) The mixed powder is placed in a box-type resistance furnace and heated at 900 to 950°C for 2 to 3 hours. After cooling, the wollastonite-feldspar composite powder is obtained.

3. The high-temperature refractory and heat-insulating carbon fiber composite material according to claim 1, characterized in that, The modified porous mullite aggregate is prepared by the following method: porous mullite aggregate raw material with Al2O3 content ≥75% and particle size of 50-200μm is immersed in a silica sol solution with a concentration of 5-10%, stirred for 30-50 minutes, then taken out and placed in an electric heating constant temperature drying oven, and dried at 75-85℃ for 2-3 hours to obtain the modified porous mullite aggregate.

4. The high-temperature refractory and heat-insulating carbon fiber composite material according to claim 1, characterized in that, The calcium aluminate cement is CA-50 type industrial grade calcium aluminate cement, wherein the Al2O3 content is ≥50%.

5. The high-temperature refractory and heat-insulating carbon fiber composite material according to claim 1, characterized in that, The modified chopped carbon fiber is prepared by the following method: (1) The chopped carbon fiber is placed in a muffle furnace and calcined at 400-450°C for 20-30 minutes. After cooling, the oxidized chopped carbon fiber is obtained; (2) The oxidized chopped carbon fiber is placed in a high-speed mixer. The silane coupling agent KH-560 is added to the high-speed mixer according to the mass ratio of oxidized chopped carbon fiber to silane coupling agent KH-560 of 50-70:

1. The speed of the high-speed mixer is set to 1300-1500 r / min. The mixture is dry-mixed for 6-10 minutes to obtain the modified chopped carbon fiber.

6. The high-temperature refractory and heat-insulating carbon fiber composite material according to claim 1, characterized in that, The sodium dodecylbenzenesulfonate was pretreated by the following method: the sodium dodecylbenzenesulfonate was placed in an electric thermostatic drying oven and dried at 60-80°C for 1-2 hours. After drying, it was cooled to room temperature and passed through a 200-mesh sieve. The sieved sodium dodecylbenzenesulfonate was then transferred to a brown sealed bottle for later use.

7. The high-temperature refractory and heat-insulating carbon fiber composite material according to claim 1, characterized in that, The sodium tripolyphosphate used is industrial grade sodium tripolyphosphate with a purity ≥98% and a water solubility of ≥95g / 100mL at room temperature.

8. A method for preparing a high-temperature refractory and heat-insulating carbon fiber composite material, comprising the following steps: S1. Weigh out wollastonite-feldspar composite powder, modified porous mullite aggregate, calcium aluminate cement and modified short-cut carbon fiber according to the proportion, put them into a high-speed mixer, set the speed to 800-1000 r / min, dry mix for 8-12 minutes to obtain a dry powder mixture. S2. Weigh out deionized water and place it in a mixing tank according to the mass ratio of dry powder mixture to water of 20:5-7. Add sodium dodecylbenzenesulfonate and sodium tripolyphosphate to the deionized water in proportion. Set the speed of the mixing tank to 500-600 r / min and stir for 15-20 minutes to obtain an aqueous solution of the additives. S3. Adjust the speed of the high-speed mixer to 400-500 r / min, and slowly add the aqueous solution of the additive to the dry powder mixture through the feed inlet at a rate of 5-10 L / h. After the addition is completed, continue stirring for 20-30 minutes to obtain the slurry. S4. Quickly transfer the slurry into the customized mold, use a scraper to smooth the surface of the slurry, send the smoothed mold into the hydraulic forming machine, apply a pressure of 15-25MPa, hold the pressure for 3-5 minutes, and obtain the molded blank. S5. Place the molded blank along with the mold into a constant temperature and humidity curing chamber, set the curing temperature to 20-28℃ and the relative humidity to 70-80%, and cure for 20-40 hours. Then, place it into a hydraulic demolding machine for demolding. After demolding, place it into an electric heating constant temperature drying oven for drying. Slowly raise the temperature to 110℃ at a rate of 5℃ per hour and hold it at 110℃ for 3-5 hours. After drying, place it into a high temperature sintering furnace. Under a nitrogen atmosphere, raise the temperature to 1100-1200℃ at a rate of 3-5℃ per minute and sinter at this temperature for 2-4 hours. After sintering, cool it to room temperature and remove it to obtain the finished high temperature refractory and heat-insulating carbon fiber composite material.

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