High-temperature-resistant high-strength aerogel thermal insulation material and preparation method thereof

Abstract

The application relates to a high-temperature-resistant high-strength aerogel thermal insulation material and a preparation method thereof. The method comprises the following steps: uniformly mixing aluminum oxide nano powder, aluminum silicate fiber, aluminum oxide fiber and an acidic solution with water to obtain a mixed solution, then carrying out hydrothermal reaction on the mixed solution at 200-300 DEG C to obtain a gel; the acidic solution is a hydrochloric acid and / or sulfuric acid solution; the gel is soaked in water to obtain a soaking treatment gel; the soaking treatment gel is dried under normal pressure to obtain an aerogel material; and the aerogel material is heat treated in an air atmosphere to obtain the high-temperature-resistant high-strength aerogel thermal insulation material. The aerogel thermal insulation material prepared by the application is a cage-shaped nano structure surrounded by nanometer strips, has better mechanical strength, does not need a supercritical drying process, and can directly obtain the high-temperature-resistant aerogel thermal insulation material with good temperature resistance, high strength, high efficiency, low density and excellent high-temperature thermal insulation performance through a normal pressure drying and a relatively low-temperature heat treatment step.

Description

Technical Field

[0001] This invention relates to the field of aerogel preparation technology, and in particular to a high-temperature resistant, high-strength aerogel insulation material and its preparation method. Background Technology

[0002] Nanoporous aerogels (or simply aerogels) are gel materials with a gaseous dispersion medium. They are nanoporous solid materials with a network structure, composed of colloidal particles or polymer molecules aggregated together. The pore size in these materials is on the nanometer scale. Their porosity can be as high as 80–99.8%, the typical pore size is 1–100 nm, and the density can be as low as 3 kg / m³. 3 Aerogels have low thermal conductivity at room temperature. These characteristics give aerogels broad application potential in thermal, acoustic, optical, microelectronic, and particle detection fields. Currently, the most widespread application of aerogels remains in thermal insulation, as their unique nanostructure effectively reduces convection, solid-phase conduction, and thermal radiation.

[0003] Traditional aerogel materials are mostly pearl necklace-like structures formed by the stacking of nanoparticles. The drying process often requires supercritical drying, which significantly increases the preparation cycle and cost. Furthermore, this type of aerogel material is brittle, requiring structural reinforcement for practical applications. However, existing structural reinforcement processes lead to increased density, increased solid-state thermal conductivity, and increased process complexity. In addition, some methods for strengthening the framework produce aerogel materials with good structural strength; however, these methods often require complex high-temperature sintering processes to increase the framework size and thus improve the material's strength, which also introduces new problems such as high thermal conductivity and brittleness. With the development of technology, various fields are placing higher demands on the strength, temperature resistance, lightweight, and / or thermal insulation performance of aerogel insulation materials.

[0004] In summary, it is essential to provide a high-temperature resistant, high-strength aerogel insulation material and its preparation method. Summary of the Invention

[0005] To address one or more technical problems existing in the prior art, this invention provides a high-temperature resistant, high-strength aerogel insulation material and its preparation method.

[0006] In a first aspect, this invention provides a method for preparing a high-temperature resistant, high-strength aerogel insulation material, the method comprising the following steps:

[0007] (1) Alumina nanopowder, aluminum silicate fiber, alumina fiber and acidic solution are mixed evenly with water to obtain a mixture. Then the mixture is placed at 200-300℃ for hydrothermal reaction to obtain a gel. The acidic solution is hydrochloric acid and / or sulfuric acid solution. The mass fraction of alumina nanopowder contained in the mixture is 8-20%.

[0008] (2) Soak the gel in water for 6-72 hours to obtain soaking-treated gel;

[0009] (3) The soaking gel obtained in step (2) is dried under normal pressure to obtain aerogel material;

[0010] (4) The aerogel material obtained in step (3) is heat-treated in an air atmosphere to obtain a high-temperature resistant and high-strength aerogel insulation material.

[0011] Preferably, the mixture further contains titanium dioxide powder; the mass fraction of titanium dioxide nanoparticles contained in the mixture is 0.5-10%, preferably 1-5%.

[0012] Preferably, the mixture contains 1-15% by mass of aluminum silicate fiber, more preferably 1-4%; and / or the mixture contains 1-3% by mass of alumina fiber.

[0013] Preferably, the mass ratio of the aluminum silicate fiber to the alumina fiber is (1-3):1, more preferably 2:1.

[0014] Preferably, the hydrothermal reaction time is 1 to 48 hours, and more preferably 3 to 12 hours.

[0015] Preferably, the temperature for atmospheric pressure drying is 25–80°C, and the drying time is 12–120 h.

[0016] Preferably, the heat treatment temperature is 600–1000°C, and the heat treatment time is 0.5–2 hours.

[0017] Preferably, the concentration of the acidic solution is 0.1–5 mol / L; and / or the amount of the acidic solution accounts for 0.3–5% of the total mass of the mixture.

[0018] Preferably, the high-temperature resistant and high-strength aerogel insulation material has a cage-like structure surrounded by nanoribbons.

[0019] In a second aspect, the present invention provides a high-temperature resistant, high-strength aerogel insulation material prepared by the method described in the first aspect of the present invention.

[0020] Compared with the prior art, the present invention has at least the following beneficial effects:

[0021] (1) Compared with traditional pearl necklace-shaped aerogel materials, the high-temperature resistant and high-strength aerogel insulation material prepared by the present invention is a cage-like nanostructure surrounded by nanobelts, with a porosity of up to about 95%, ultra-lightweight properties, a heat resistance temperature of up to 1200℃ or more, and better mechanical strength.

[0022] (2) The method of the present invention uses an aqueous phase as the reaction medium and does not require a supercritical drying process or a relatively high temperature heat treatment process or a complex stepwise heat treatment process. The preparation process avoids environmental pollution and waste caused by the use of organic solvents. The present invention can directly obtain the high temperature resistant and high strength aerogel insulation material by soaking the gel in water and then drying it under normal pressure and heat treatment at a relatively low temperature.

[0023] (3) The gelation process in the preparation method of the present invention is a hydrothermal process, which is different from the traditional RTM pressure injection process. It is not limited by the shape and size of the reinforcement and can prepare aerogel materials of any shape and thickness.

[0024] (4) The high-temperature resistant and high-strength aerogel insulation material prepared by some preferred technical solutions of the present invention has excellent heat insulation performance at high temperature because it contains uniform anti-radiation agent titanium dioxide nanopowder.

[0025] (5) The high-temperature resistant and high-strength aerogel insulation material prepared by the present invention has a very low density. Compared with other aerogel materials of the same strength, it has the characteristic of ultra-low density. The aerogel material prepared by the method of the present invention has excellent high-temperature resistance while maintaining low thermal conductivity, and can achieve long-term thermal insulation application at 1200℃. The present invention obtains a high-strength aerogel insulation material with good temperature resistance, high strength, low density and good high-temperature thermal insulation performance. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating the preparation process of some specific embodiments of the present invention.

[0027] Figure 2 This is a SEM image of the high-temperature resistant and high-strength aerogel insulation material prepared in Example 1 of this invention.

[0028] Figure 3 This is an optical photograph of the high-temperature resistant and high-strength aerogel thermal insulation material prepared in Example 2 of the present invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0030] In a first aspect, this invention provides a method for preparing a high-temperature resistant, high-strength aerogel insulation material, the preparation process of which is illustrated in the following flowchart: Figure 1 As shown, the method includes the following steps:

[0031] (1) Alumina nanoparticles, aluminum silicate fibers, alumina fibers and an acidic solution are mixed evenly with water to obtain a mixture. The mixture is then subjected to a hydrothermal reaction at 200-300°C to obtain a gel. The acidic solution is hydrochloric acid and / or sulfuric acid solution. The mass fraction of alumina nanoparticles contained in the mixture is 8-20% (e.g., 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%). In this invention, both the hydrochloric acid and the sulfuric acid solution are known to be aqueous solutions, i.e., hydrochloric acid aqueous solution and sulfuric acid aqueous solution, respectively.

[0032] (2) The gel is soaked in water for 6 to 72 hours (e.g., 6, 12, 18, 24, 30, 36, 42, 48, 60, 66 or 72 hours) to obtain an soaked gel. In this invention, the gel is aged by soaking in water. Water has good diffusivity and uniformity, and can penetrate into the gel evenly, making the aging process more uniform. Water soaking aging can provide uniform wetting conditions, which helps the internal reaction of the gel to proceed evenly, helps to form a finer pore structure, helps to reduce cracks and defects in the final aerogel, and provides a higher specific surface area. Moreover, the soaking aging process can enhance the uniformity and connectivity of the gel material. Aging in water helps to form a more stable gel structure, which is beneficial to the subsequent atmospheric pressure drying process. In this invention, the soaking is carried out at room temperature, for example, soaking in water at room temperature of 20 to 35°C for 6 to 72 hours.

[0033] (3) The soaking gel obtained in step (2) is dried under normal pressure to obtain aerogel material;

[0034] (4) The aerogel material obtained in step (3) is heat-treated in an air atmosphere to obtain a high-temperature resistant and high-strength aerogel insulation material.

[0035] This invention discovers that by subjecting a mixture containing alumina nanoparticles, aluminosilicate fibers, and an acidic solution to a hydrothermal reaction, the aluminosilicate fibers and alumina fibers can participate in the reaction, allowing the alumina nanoparticles to interact with the aluminosilicate fibers and alumina fibers. This interaction may lead to cross-linking, cross-connection, or encapsulation of the alumina nanoparticles with the aluminosilicate fibers and alumina fibers at the nanoscale, constructing a precursor (gel) with a cage-like structure surrounded by nanoribbons. Preferably, when constructing this gel, uniform doping with anti-radiation titanium dioxide nanoparticles is performed. In this invention, it is possible to... This aerogel material primarily uses aluminosilicate fibers, supplemented by alumina fibers. Together, the aluminosilicate and alumina fibers act as templaters and support agents, guiding the alumina nanoparticles to form a gel morphology. This provides a template effect for the formation of the cage-like structure surrounded by nanoribbons, and helps maintain the stability and strength of the gel structure. This facilitates the subsequent atmospheric pressure drying process. After atmospheric pressure drying and heat treatment, the cage-like structure surrounded by nanoribbons in the aerogel material is maintained and strengthened, ultimately constructing a high-temperature resistant, high-strength aerogel insulation material with a cage-like structure surrounded by nanoribbons. For example, ... Figure 2 As shown; in some preferred embodiments, a high-temperature resistant and high-strength aerogel insulation material with a cage-like structure surrounded by nanoribbons and doped with titanium dioxide nanoparticles is finally constructed. The present invention found that if only aluminum silicate fiber or alumina fiber is added to the mixture, structural shrinkage is likely to occur during the preparation process, and the cage-like structure surrounded by nanoribbons cannot be formed. This will result in a significant decrease in the specific surface area and an increase in density of the formed aerogel material, and there may be large gaps and interfaces, which will cause more scattering of heat transfer, resulting in a significant increase in thermal conductivity and a decrease in insulation performance. In the present invention, only by carrying out a hydrothermal reaction with alumina nanoparticles, aluminum silicate fiber and alumina fiber together can the formation of a cage-like structure surrounded by nanoribbons be guaranteed, and the aerogel material can have a high specific surface area, low density and low thermal conductivity, ensuring that the aerogel material has excellent insulation performance and high temperature resistance, and can withstand temperatures above 1200℃. This invention has found that if alumina nanopowder is subjected to a hydrothermal reaction with fibers such as mullite fiber, basalt fiber or glass fiber, only physical doping and entanglement between alumina aerogel and fibers can be achieved, and it is also impossible to form an aerogel material with a cage-like structure surrounded by nanoribbons.

[0036] Compared to traditional pearl necklace-like aerogel materials, the high-temperature resistant, high-strength aerogel insulation material prepared by this invention has a cage-like nanostructure surrounded by nanoribbons, exhibiting high porosity, ultra-lightweight properties, and a heat resistance temperature exceeding 1200℃, enabling long-term insulation applications at 1200℃, while also possessing superior mechanical strength. This invention yields a high-strength aerogel insulation material with excellent temperature resistance, high strength, low density, and superior high-temperature insulation performance. The method of this invention directly obtains the high-temperature resistant, high-strength aerogel insulation material by soaking the gel in water followed by atmospheric pressure drying and relatively low-temperature heat treatment, eliminating the need for supercritical drying processes and complex stepwise heat treatments or relatively high-temperature heat treatments. This invention simplifies the preparation process, reduces process steps and operational difficulties, lowers the complexity and cost of the preparation process, helps save energy, and avoids environmental pollution and waste caused by the use of organic solvents. This invention employs simpler, more environmentally friendly, and more easily controlled steps, contributing to obtaining a high-temperature resistant, high-strength aerogel insulation material with more stable quality and superior performance.

[0037] According to some preferred embodiments, the mixture further contains titanium dioxide powder, that is, step (1) is: mixing alumina nanoparticles, aluminum silicate fibers, alumina fibers, titanium dioxide nanoparticles and sulfuric acid solution evenly with water to obtain a mixture, and then placing the mixture at 200-300°C for hydrothermal reaction to obtain a gel; the mass fraction of titanium dioxide nanoparticles contained in the mixture is 0.5-10% (e.g. 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%), preferably 1-5%.

[0038] According to some preferred embodiments, the mixture contains 1 to 15% (e.g., 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, or 15%) of aluminum silicate fiber, preferably 1 to 4% (e.g., 1%, 2%, 3%, or 4%); and / or the mixture contains 1 to 3% (e.g., 1%, 2%, or 3%) of alumina fiber.

[0039] According to some preferred embodiments, the mass ratio of the aluminosilicate fiber to the alumina fiber is (1-3):1 (e.g., 1:1, 1.5:1, 2:1, 2.5:1 or 3:1), preferably 2:1.

[0040] In this invention, the preferred mass ratio of the aluminosilicate fiber to the alumina fiber is (1-3):1. By using a reasonable ratio, the advantages of both can be fully utilized to obtain better overall performance, which helps to obtain a high-temperature resistant and high-strength aerogel insulation material with superior performance. If the ratio of aluminosilicate fiber to alumina fiber is not within a reasonable range, it may affect the pore structure and skeleton strength of the aerogel material, thereby affecting the porosity, specific surface area, thermal conductivity, etc. of the aerogel material.

[0041] This invention does not specifically limit the alumina nanopowder, titanium dioxide nanopowder, aluminum silicate fiber, and alumina fiber; commercially available products or products synthesized by existing methods can be used. Preferably, the alumina nanopowder has a particle size of 10–100 nm, more preferably 10–25 nm; the titanium dioxide nanopowder has a particle size of 20–100 nm, more preferably 20–40 nm; the aluminum silicate fiber has a length of 1–3 mm and a diameter of 2–9 μm; and the alumina fiber has a length of 1–5 mm and a diameter of 4–9 μm.

[0042] According to some preferred embodiments, the hydrothermal reaction time is 1 to 48 hours (e.g., 1, 3, 5, 10, 12, 15, 18, 20, 25, 30, 36, 40, 45 or 48 hours), preferably 3 to 12 hours (e.g., 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12 hours).

[0043] According to some preferred embodiments, the temperature of the atmospheric pressure drying is 25-80°C (e.g., 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, or 80°C), and the time of the atmospheric pressure drying is 12-120h (e.g., 12, 24, 36, 48, 60, 72, 84, 96, 108, or 120h), preferably 24-48h.

[0044] According to some preferred embodiments, the heat treatment temperature is 600–1000°C (e.g., 600°C, 700°C, 800°C, 900°C, or 1000°C), preferably 600–800°C (e.g., 600°C, 700°C, or 800°C), and the heat treatment time is 0.5–2 hours (e.g., 0.5, 1, 1.5, or 2 hours).

[0045] Compared to heat treatment at a relatively low temperature of 600–1000°C, the present invention can produce a high-temperature resistant and high-strength aerogel insulation material with comparable performance by performing heat treatment at a relatively high temperature of 1000–1200°C.

[0046] According to some embodiments, the concentration of the acidic solution is 0.1–5 mol / L, preferably 1–5 mol / L; and / or the amount of the acidic solution accounts for 0.3–5% of the total mass of the mixture, preferably 1–3%.

[0047] According to some specific embodiments, the preparation process of the high-temperature resistant and high-strength aerogel insulation material of the present invention is as follows: Figure 1 As shown, the method includes the following steps:

[0048] (1) Alumina nanoparticles, aluminum silicate fibers, alumina fibers, titanium dioxide nanoparticles, and sulfuric acid solution (aqueous sulfuric acid solution) are mixed evenly with water to obtain a mixed liquid. The alumina nanoparticles, aluminum silicate fibers, alumina fibers, and titanium dioxide nanoparticles are then mixed evenly using a high-speed disperser. The mixed liquid is then subjected to a hydrothermal reaction at 200–300°C for 1–48 hours to obtain a gel. The mass fraction of alumina nanoparticles in the mixed liquid is 8–20%, the mass fraction of aluminum silicate fibers is 1–15%, and the mass fraction of alumina fibers is 1–3%. The liquid contains 0.5-10% titanium dioxide nanopowder; in step (1), the mixture is mixed evenly, for example by high-speed dispersion, specifically: after mixing alumina nanopowder, aluminum silicate fiber, alumina fiber, titanium dioxide nanopowder and sulfuric acid solution with water, the mixture is dispersed at 1000-8000 r / min for 5-120 min in a high-speed disperser; in this invention, the mixture is placed in a sealed container and hydrothermally reacted at 200-300℃; in this invention, the hydrothermal reaction needs to be carried out under sealed conditions, and the material of the sealed container needs to be a material that does not react with the system;

[0049] (2) Soak the obtained gel in pure water for 6-72 hours;

[0050] (3) The obtained soaking-treated gel material is dried under normal pressure at a temperature of 25-80℃ for 12-120 hours; the normal pressure drying is, for example, drying in an oven under normal pressure.

[0051] (4) Heat treatment is performed on the dried aerogel material. The air atmosphere heat treatment temperature is 600-1000℃ to obtain a high-temperature resistant and high-strength aerogel insulation material.

[0052] According to some preferred embodiments, the high-temperature resistant, high-strength aerogel insulation material has a cage-like structure surrounded by nanoribbons, for example, as... Figure 2 As shown, Figure 2This invention demonstrates that the high-temperature resistant and high-strength aerogel insulation material obtained by the present invention has a cage-like structure surrounded by nanoribbons. Specifically, the skeleton structure of the high-temperature resistant and high-strength aerogel insulation material in the present invention is a cage-like structure surrounded by nanoribbons.

[0053] According to some preferred embodiments, the density of the high-temperature resistant, high-strength aerogel insulation material is as low as 0.25 g / cm³. 3 It has a high porosity of 93.8% and a specific surface area of ​​165 m². 2 / g, the compressive strength at 10% compression is 1.45MPa, the thermal conductivity at 1000℃ is as low as 0.067W / (m·K), and the heat resistance temperature is above 1200℃.

[0054] The present invention provides, in a second aspect, a high-temperature resistant and high-strength aerogel insulation material prepared by the method described in the first aspect of the present invention.

[0055] The present invention will be further described below by way of examples, but the scope of protection of the present invention is not limited to these embodiments.

[0056] Example 1

[0057] (1) Alumina nanoparticles, aluminum silicate fibers, alumina fibers and hydrochloric acid are mixed with water and dispersed in a high-speed disperser at a speed of 5000 r / min for 30 min to obtain a uniform mixture; then the mixture is placed in a hydrothermal reaction at 220℃ for 5 h to obtain a gel; the mass fraction of alumina nanoparticles in the mixture is 10%, the mass fraction of aluminum silicate fibers in the mixture is 2%, and the mass fraction of alumina fibers in the mixture is 1%; the amount of hydrochloric acid used accounts for 1.5% of the total weight of the mixture, and the concentration of hydrochloric acid is 2 mol / L.

[0058] (2) The obtained gel was placed in pure water at room temperature (25°C) for 24 hours to obtain the soaked gel.

[0059] (3) The obtained soaking gel was dried under normal pressure at a temperature of 60°C for 24 hours to obtain aerogel material.

[0060] (4) The obtained aerogel material is subjected to heat treatment to obtain a high-temperature resistant and high-strength aerogel insulation material; the heat treatment temperature is 600℃, the heat treatment time is 1h, and the heat treatment is carried out in an air atmosphere.

[0061] The high-temperature resistant and high-strength aerogel insulation material prepared in this embodiment has excellent structural strength. When the insulation performance was tested, it was found that the surface of the high-temperature resistant and high-strength aerogel insulation material did not lose its gloss, change color, or peel off.

[0062] The density of the high-temperature resistant, high-strength aerogel insulation material prepared in this embodiment is 0.2 g / cm³. 3 Specific surface area is 152m² 2 With a porosity of 93.5%, a compressive strength of 1.3 MPa at 10% compression, and a heat resistance temperature of 1200℃, this is a high-temperature resistant, high-strength aerogel insulation material with excellent temperature resistance, large specific surface area, low porosity, high strength, low density, and good thermal insulation performance. The heat resistance temperature is tested by heat-treating the aerogel material obtained in each embodiment at a certain high temperature (in air) for 2 hours. If the linear shrinkage rate of the aerogel material is no greater than 5%, it indicates that the aerogel material can withstand that high temperature. In this embodiment, the high-temperature resistant, high-strength aerogel insulation material obtained in this embodiment, after heat treatment at 1200℃ (in air) for 2 hours, exhibits a linear shrinkage rate of no more than 5% and a heat resistance temperature of 1200℃, enabling long-term thermal insulation applications at 1200℃.

[0063] Example 2

[0064] (1) Alumina nanoparticles, aluminum silicate fibers, alumina fibers, titanium dioxide nanoparticles and sulfuric acid solution are mixed with water and dispersed in a high-speed disperser at 5000 r / min for 30 min to obtain a uniform mixture; then the mixture is placed in a hydrothermal reaction at 230℃ for 10 h to obtain a gel; the mass fraction of alumina nanoparticles in the mixture is 10%, the mass fraction of aluminum silicate fibers in the mixture is 2%, the mass fraction of alumina fibers in the mixture is 1%, the mass fraction of titanium dioxide nanoparticles in the mixture is 1%; the amount of sulfuric acid solution is 1.5% of the total weight of the mixture, and the concentration of the sulfuric acid solution is 2 mol / L.

[0065] (2) The obtained gel was placed in pure water at room temperature (25°C) for 24 hours to obtain the soaked gel.

[0066] (3) The obtained soaking gel was dried under normal pressure at a temperature of 60°C for 24 hours to obtain aerogel material.

[0067] (4) The obtained aerogel material is subjected to heat treatment to obtain a high-temperature resistant and high-strength aerogel insulation material; the heat treatment temperature is 600℃, the heat treatment time is 1h, and the heat treatment is carried out in an air atmosphere.

[0068] The high-temperature resistant and high-strength aerogel insulation material prepared in this embodiment has excellent structural strength. When the insulation performance was tested, it was found that the surface of the high-temperature resistant and high-strength aerogel insulation material did not lose its gloss, change color, or peel off.

[0069] The density of the high-temperature resistant, high-strength aerogel insulation material prepared in this embodiment is 0.25 g / cm³. 3 Specific surface area is 165m² 2 With a porosity of 93.8%, a compressive strength of 1.45 MPa at 10% compression, and a heat resistance temperature of 1200℃, this high-temperature resistant, high-strength aerogel insulation material exhibits excellent temperature resistance, large specific surface area, low porosity, high strength, low density, and good high-temperature insulation performance.

[0070] Example 3

[0071] Example 3 is basically the same as Example 2, except that:

[0072] (1) Alumina nanoparticles, alumina fibers, titanium dioxide nanoparticles and sulfuric acid solution are mixed with water and dispersed in a high-speed disperser at 5000 r / min for 30 min to obtain a uniform mixture; then the mixture is placed in a hydrothermal reaction at 230℃ for 10 h to obtain a gel; the mass fraction of alumina nanoparticles in the mixture is 10%, the mass fraction of alumina fibers in the mixture is 3%, and the mass fraction of titanium dioxide nanoparticles in the mixture is 1%; the amount of sulfuric acid solution is 1.5% of the total weight of the mixture, and the concentration of the sulfuric acid solution is 2 mol / L.

[0073] Although the aerogel material prepared by steps (1) to (4) in this embodiment has good structural strength, it shrinks significantly during the normal pressure drying process, resulting in a large material density, a small specific surface area, and a significantly increased thermal conductivity. The performance test results are shown in Table 1.

[0074] Example 4

[0075] Example 4 is basically the same as Example 2, except that:

[0076] (1) Alumina nanoparticles, aluminum silicate fibers, titanium dioxide nanoparticles and sulfuric acid solution are mixed with water and dispersed in a high-speed disperser at a speed of 5000 r / min for 30 min to obtain a uniform mixture; then the mixture is placed in a hydrothermal reaction at 230℃ for 10 h to obtain a gel; the mass fraction of alumina nanoparticles in the mixture is 10%, the mass fraction of aluminum silicate fibers in the mixture is 3%, and the mass fraction of titanium dioxide nanoparticles in the mixture is 1%; the amount of sulfuric acid solution is 1.5% of the total weight of the mixture, and the concentration of the sulfuric acid solution is 2 mol / L.

[0077] Although the aerogel material prepared by steps (1) to (4) in this embodiment has good structural strength, it shrinks during the normal pressure drying process, resulting in a large material density, small specific surface area, and increased thermal conductivity. The performance test results are shown in Table 1.

[0078] Example 5

[0079] Example 5 is basically the same as Example 2, except that:

[0080] (1) Alumina nanoparticles, aluminum silicate fibers, alumina fibers, titanium dioxide nanoparticles and sulfuric acid solution are mixed with water and dispersed in a high-speed disperser at 5000 r / min for 30 min to obtain a uniform mixture; then the mixture is placed in a hydrothermal reaction at 230℃ for 10 h to obtain a gel; the mass fraction of alumina nanoparticles in the mixture is 10%, the mass fraction of aluminum silicate fibers in the mixture is 0.5%, the mass fraction of alumina fibers in the mixture is 0.5%, and the mass fraction of titanium dioxide nanoparticles in the mixture is 1%; the amount of sulfuric acid solution is 1.5% of the total weight of the mixture, and the concentration of the sulfuric acid solution is 2 mol / L.

[0081] The performance test results of the high-temperature resistant and high-strength aerogel insulation material obtained by steps (1) to (4) in this embodiment are shown in Table 1.

[0082] Example 6

[0083] Example 6 is basically the same as Example 2, except that:

[0084] (1) Alumina nanoparticles, aluminum silicate fibers, alumina fibers, titanium dioxide nanoparticles and sulfuric acid solution are mixed with water and dispersed in a high-speed disperser at a speed of 5000 r / min for 30 min to obtain a uniform mixture; then the mixture is placed in a hydrothermal reaction at 230℃ for 10 h to obtain a gel; the mass fraction of alumina nanoparticles in the mixture is 10%, the mass fraction of aluminum silicate fibers in the mixture is 10%, the mass fraction of alumina fibers in the mixture is 1%, and the mass fraction of titanium dioxide nanoparticles in the mixture is 1%; the amount of sulfuric acid solution is 1.5% of the total weight of the mixture, and the concentration of the sulfuric acid solution is 2 mol / L.

[0085] The performance test results of the aerogel materials prepared in steps (1) to (4) of this embodiment are shown in Table 1.

[0086] Example 7

[0087] Example 7 is basically the same as Example 2, except that:

[0088] ① Alumina nanoparticles, aluminum silicate fibers, alumina fibers, titanium dioxide nanoparticles, and sulfuric acid solution are mixed with water and dispersed in a high-speed disperser at 5000 r / min for 30 min to obtain a uniform mixture. Then, the mixture is subjected to hydrothermal reaction at 150℃ for 10 h to obtain a gel. The mass fraction of alumina nanoparticles in the mixture is 10%, the mass fraction of aluminum silicate fibers is 2%, the mass fraction of alumina fibers is 1%, and the mass fraction of titanium dioxide nanoparticles is 1%. The amount of sulfuric acid solution used accounts for 1.5% of the total weight of the mixture, and the concentration of the sulfuric acid solution is 2 mol / L.

[0089] In this embodiment, the hydrothermal reaction temperature is relatively low, which makes it impossible to form a very complete block. The aerogel material shrinks, resulting in a significant reduction in the porosity and specific surface area of ​​the prepared aerogel material. Other performance test results are shown in Table 1.

[0090] Example 8

[0091] Example 8 is basically the same as Example 2, except that:

[0092] (1) Alumina nanoparticles, aluminum silicate fibers, alumina fibers, titanium dioxide nanoparticles and sulfuric acid solution are mixed with water and dispersed in a high-speed disperser at 5000 r / min for 30 min to obtain a uniform mixture; then the mixture is placed in a hydrothermal reaction at 230℃ for 10 h to obtain a gel; the mass fraction of alumina nanoparticles in the mixture is 25%, the mass fraction of aluminum silicate fibers in the mixture is 2%, the mass fraction of alumina fibers in the mixture is 1%, and the mass fraction of titanium dioxide nanoparticles in the mixture is 1%; the amount of sulfuric acid solution is 1.5% of the total weight of the mixture, and the concentration of the sulfuric acid solution is 2 mol / L.

[0093] The performance test results of the aerogel materials prepared in steps (1) to (4) of this embodiment are shown in Table 1.

[0094] Although the aerogel material prepared by steps (1) to (4) in this embodiment has good structural strength, the specific surface area of ​​the material is very small and the thermal conductivity increases at 1000℃.

[0095] Example 9

[0096] Example 9 is basically the same as Example 2, except that:

[0097] (1) Alumina nanoparticles, aluminum silicate fibers, alumina fibers, titanium dioxide nanoparticles and sulfuric acid solution are mixed with water and dispersed in a high-speed disperser at a speed of 5000 r / min for 30 min to obtain a uniform mixture; then the mixture is placed in a hydrothermal reaction at 230℃ for 10 h to obtain a gel; the mass fraction of alumina nanoparticles in the mixture is 4%, the mass fraction of aluminum silicate fibers in the mixture is 2%, the mass fraction of alumina fibers in the mixture is 1%, and the mass fraction of titanium dioxide nanoparticles in the mixture is 1%; the amount of sulfuric acid solution is 1.5% of the total weight of the mixture, and the concentration of the sulfuric acid solution is 2 mol / L.

[0098] The performance test results of the aerogel materials prepared in steps (1) to (4) of this embodiment are shown in Table 1.

[0099] Example 10

[0100] Example 10 is basically the same as Example 2, except that:

[0101] (4) The obtained aerogel material is subjected to heat treatment to obtain a high-temperature resistant and high-strength aerogel insulation material; the heat treatment temperature is 500℃, the heat treatment time is 1h, and the heat treatment is carried out in an air atmosphere.

[0102] The performance test results of the aerogel materials prepared in steps (1) to (4) of this embodiment are shown in Table 1.

[0103] Comparative Example 1

[0104] Comparative Example 1 is basically the same as Example 2, except that:

[0105] (2) The obtained gel was aged in an airless environment at 60°C for 2 hours to obtain an aged gel block; the aged gel block was used for subsequent steps (3) and (4).

[0106] The performance test results of the aerogel materials prepared in steps (1) to (4) of this comparative example are shown in Table 1.

[0107] Comparative Example 2

[0108] Comparative Example 2 is basically the same as Example 2, except that:

[0109] (1) Alumina nanoparticles, mullite fibers, basalt fibers, titanium dioxide nanoparticles and sulfuric acid solution are mixed with water and dispersed in a high-speed disperser at 5000 r / min for 30 min to obtain a uniform mixture. Then the mixture is placed in a hydrothermal reaction at 230℃ for 10 h to obtain a gel. The mass fraction of alumina nanoparticles in the mixture is 10%, the mass fraction of mullite fibers in the mixture is 2%, the mass fraction of basalt fibers in the mixture is 1%, and the mass fraction of titanium dioxide nanoparticles in the mixture is 1%. The amount of sulfuric acid solution used accounts for 1.5% of the total weight of the mixture, and the concentration of the sulfuric acid solution is 2 mol / L.

[0110] The performance test results of the aerogel materials prepared in steps (1) to (4) of this comparative example are shown in Table 1.

[0111] Comparative Example 3

[0112] (1) Alumina nanoparticles, aluminum silicate fibers, alumina fibers, titanium dioxide nanoparticles and sulfuric acid solution are mixed with water and dispersed in a high-speed disperser at a speed of 5000 r / min for 30 min to obtain a uniform mixture; then the mixture is placed in a hydrothermal reaction at 230℃ for 10 h to obtain a gel; the mass fraction of alumina nanoparticles in the mixture is 10%, the mass fraction of aluminum silicate fibers in the mixture is 2%, the mass fraction of alumina fibers in the mixture is 1%, and the mass fraction of titanium dioxide nanoparticles in the mixture is 1%; the amount of sulfuric acid solution is 1.5% of the total weight of the mixture, and the concentration of the sulfuric acid solution is 2 mol / L.

[0113] (2) The obtained gel was aged in an airless environment at 60°C for 2 hours to obtain an aged gel.

[0114] (3) The aged gel is subjected to solvent replacement and supercritical drying in sequence to obtain aerogel material; the specific steps are as follows: the solvent replacement uses ethanol as solvent, and the replacement is carried out 3 times according to 10 times the volume of the soaked gel block, and the solvent replacement time is 3 days each time; then the supercritical carbon dioxide drying process is carried out, the supercritical drying temperature is 50℃, the pressure is 14MPa, and the time is 24h.

[0115] (4) The obtained aerogel material is subjected to heat treatment to obtain composite aerogel material; the heat treatment temperature is 1150℃, the heat treatment time is 0.5h, and the heat treatment is carried out in an air atmosphere.

[0116] The performance test results of the aerogel materials prepared in steps (1) to (4) of this comparative example are shown in Table 1.

[0117] Comparative Example 4

[0118] Comparative Example 4 is basically the same as Example 2, except that:

[0119] (1) Alumina nanoparticles, titanium dioxide nanoparticles and sulfuric acid solution are mixed with water and dispersed in a high-speed disperser at a speed of 5000 r / min for 30 min to obtain a uniform mixture; then the mixture is placed in a hydrothermal reaction at 230℃ for 10 h to obtain a gel; the mass fraction of alumina nanoparticles in the mixture is 10% and the mass fraction of titanium dioxide nanoparticles in the mixture is 1%; the amount of sulfuric acid solution is 1.5% of the total weight of the mixture and the concentration of the sulfuric acid solution is 2 mol / L.

[0120] The performance test results of the aerogel materials prepared in steps (1) to (4) of this comparative example are shown in Table 1.

[0121]

[0122]

[0123] In Table 1, the symbol “—” indicates that the performance indicator was not tested.

[0124] The parts of this invention not described in detail are techniques known to those skilled in the art.

[0125] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a high-temperature resistant, high-strength aerogel insulation material, characterized in that, The method includes the following steps: (1) Alumina nanoparticles, aluminum silicate fibers, alumina fibers and an acidic solution are mixed evenly with water to obtain a mixture. The mixture is then subjected to a hydrothermal reaction at 200-300°C to obtain a gel. The acidic solution is hydrochloric acid and / or sulfuric acid solution. The mass fraction of alumina nanoparticles in the mixture is 8-20%. The mixture also contains titanium dioxide nanoparticles. The mass fraction of titanium dioxide nanoparticles in the mixture is 0.5-10%. The mass fraction of aluminum silicate fibers in the mixture is 1-4%, and the mass fraction of alumina fibers in the mixture is 1-3%. The mass ratio of aluminum silicate fibers to alumina fibers is (1-3):

1. (2) Soak the gel in water for 6-72 hours to obtain the soaking-treated gel; (3) The soaking gel obtained in step (2) is dried under normal pressure to obtain aerogel material; (4) The aerogel material obtained in step (3) is heat-treated in an air atmosphere to obtain a high-temperature resistant and high-strength aerogel insulation material; the high-temperature resistant and high-strength aerogel insulation material has a cage-like structure surrounded by nanobelts; the heat treatment temperature is 600~800℃ and the heat treatment time is 0.5~2h.

2. The method according to claim 1, characterized in that: The mass fraction of titanium dioxide nanoparticles contained in the mixture is 1-5%.

3. The method according to claim 1 or 2, characterized in that: The mass ratio of the aluminum silicate fiber to the alumina fiber is 2:

1.

4. The method according to claim 1 or 2, characterized in that: The hydrothermal reaction time is 1 to 48 hours.

5. The method according to claim 4, characterized in that: The hydrothermal reaction takes 3 to 12 hours.

6. The method according to claim 1 or 2, characterized in that: The temperature for atmospheric pressure drying is 25~80℃, and the drying time is 12~120h.

7. The method according to claim 1 or 2, characterized in that: The concentration of the acidic solution is 0.1~5 mol / L; and / or The amount of acidic solution used accounts for 0.3 to 5% of the total mass of the mixture.

8. A high-temperature resistant, high-strength aerogel insulation material prepared by the method of any one of claims 1 to 7.

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