A method for preparing aerogel fiber mat

Abstract

This invention discloses a method for preparing aerogel fiber felt. The method involves directly compounding aerogel slurry with fiber felt to prepare the aerogel felt, eliminating the need to dry the aerogel slurry into aerogel powder, dissolve it into aerogel slurry, and then compound it with the aerogel fiber felt. This simplifies the preparation process and saves costs. Furthermore, compared to using pre-made aerogel powder to prepare the aerogel slurry, directly using freshly prepared aerogel slurry to prepare the aerogel fiber felt avoids the use of aqueous solvents to dissolve the aerogel powder, thus preventing damage to the aerogel structure and affecting the thermal insulation performance of the aerogel fiber felt. The room temperature thermal conductivity of the aerogel fiber felt of this invention is 0.0201 W / (m·K), which is 20% lower than that of aerogel fiber felt made using pre-made aerogel powder, resulting in a significant improvement in thermal insulation performance.

Description

Technical Field

[0001] This invention relates to the field of aerogel fiber mat preparation technology, and specifically to a method for preparing aerogel fiber mat. Background Technology

[0002] Aerogel fiber felt is a high-performance thermal insulation material that is widely used in thermal insulation in many fields such as industrial production, transportation, and household appliances.

[0003] Currently, most companies producing aerogel fiber felt purchase finished aerogel powder to prepare the felt. The preparation process involves first converting the aerogel powder into an aerogel slurry, then laminating it with various pre-formed needle-punched felts, and finally drying it. This method is costly and inefficient for industrial production due to two main drawbacks: firstly, purchasing finished aerogel powder results in high costs; secondly, while most finished aerogel powder is actually obtained by drying aerogel slurry, using it to prepare aerogel fiber felt requires dissolving the powder again into a slurry, making the process complex and costly. Furthermore, the dissolution of aerogel powder often uses water as a solvent, creating an aqueous aerogel slurry which is then laminated with the fiber felt. The aqueous system can damage the structure of the aerogel powder, resulting in a higher thermal conductivity of the fiber felt. Additionally, the aqueous slurry dries more slowly, leading to lower production efficiency, and improper drying temperature control can cause the product to yellow. For example, CN112522949A discloses a method for manufacturing aerogel felt, including the following steps: S10, aerogel powder is added to water containing a wetting agent and stirred to form an aerogel slurry; S20, the aerogel slurry is injected into glass fiber felt using an injection gun; S30, the glass fiber felt is dried using a dryer; S40, water, acrylic emulsion, talc powder, VAE emulsion, and water-based curing agent are mixed and stirred evenly to prepare an impregnation solution; S50, the impregnation solution is poured into an impregnation tank, and the dried glass fiber felt is placed in the impregnation tank for immersion. After the impregnation solution adheres to the surface of the glass fiber felt, the glass fiber felt is dried using a dryer to produce aerogel felt. This technical solution uses finished aerogel powder to prepare aerogel fiber felt, which has a room temperature thermal conductivity of 0.02436 W / (m·K), which is relatively high and has poor thermal insulation performance.

[0004] Furthermore, when laminating aerogel slurry and fiber felt, existing technologies mostly employ immersion or spraying methods to laminate aerogel. This lamination method can lead to uneven aerogel impregnation, affecting the thermal insulation performance of the aerogel felt. Summary of the Invention

[0005] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a method for preparing aerogel fiber felt, which solves the problems that the preparation process of aerogel fiber felt in the prior art is complicated, the cost is high, and the aerogel fiber felt produced has uneven aerogel distribution and high thermal conductivity.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing an aerogel fiber mat includes the following steps:

[0008] (1) After dissolving the inorganic silicon source in desalinated water, an acid catalyst is slowly added to it and the reaction is complete to obtain sol A. Then, sol A is desalted by freezing to obtain sol B.

[0009] (2) Add alkaline catalyst and deionized water to sol B and react fully to obtain an aqueous gel;

[0010] (3) The aqueous gel obtained in step (2) is subjected to water bath aging, water washing and pulverization in sequence;

[0011] (4) Add solvent and surface modifier to the water-based gel after crushing in step (3), perform hydrophobic modification on the water-based gel, let it stand and separate into layers, and take the supernatant to obtain hydrophobic aerogel slurry.

[0012] (5) After opening, combing and laying the short fibers in sequence, the laid fiber web is pre-needled to obtain a preliminary fiber felt.

[0013] (6) After mixing the hydrophobic aerogel slurry and adhesive obtained in step (4) evenly, inject the mixed slurry quantitatively into the initially formed fiber felt, and then perform secondary needle punching on the initially formed fiber felt to obtain the formed fiber felt.

[0014] (7) Spray the mixed slurry obtained in step (6) onto the formed fiber felt so that the surface of the formed fiber felt is uniformly covered with hydrophobic aerogel slurry.

[0015] (8) After drying the fiber felt obtained in step (7), aerogel fiber felt is obtained.

[0016] Furthermore, in step (1), the freezing desalination is performed by cooling sol A to 0-10°C until no more crystals precipitate, filtering to remove the solid, and obtaining sol B.

[0017] Furthermore, in step (6), the hydrophobic aerogel slurry and adhesive are mixed at a mass ratio of inorganic silicon source to adhesive of 100:1 to 10.

[0018] Furthermore, the mass ratio of the inorganic silicon source, acid catalyst, and alkaline catalyst is 100:100-250:0.5-2.

[0019] Furthermore, in step (4), the mass ratio of solvent to surface modifier is 100:1 to 10.

[0020] Furthermore, in step (4), the solvent includes hexamethyldisiloxane, methanol, ethanol, n-hexane, or n-heptane.

[0021] Furthermore, in step (4), the surface modifier includes trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane or propyltrichlorosilane.

[0022] Furthermore, in step (8), the drying method is to continuously dry the fiber felt obtained in step (7) in a tunnel drying line to obtain aerogel fiber felt.

[0023] Furthermore, in step (3), the water bath aging is carried out by standing for 6 to 20 hours under a water bath at 40 to 60°C.

[0024] Furthermore, the adhesive in step (6) includes epoxy resin, acrylic resin, white glue, phenolic resin or polyurethane.

[0025] The aerogel slurry prepared by this invention uses water glass as the silicon source. The silicon source is inexpensive and the cost is controllable. The gelation speed is controlled by a two-step acid-base method. Combined with freezing desalination and water washing desalination, the quality of the product is improved. Furthermore, the undried hydrophobic aerogel slurry is directly injected and compounded with the incompletely needled fiber mat, so that the aerogel is uniformly distributed in the fiber mat, resulting in an aerogel mat with good thermal conductivity and low production cost.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The preparation method of the aerogel fiber felt of this invention involves directly compounding aerogel slurry with fiber felt to prepare the aerogel felt. This eliminates the need to dry the aerogel slurry into aerogel powder, dissolve it into aerogel slurry, and then compound it with the aerogel fiber felt, simplifying the preparation process and saving costs. Furthermore, compared to using pre-made aerogel powder to prepare the aerogel slurry, directly using freshly prepared aerogel slurry to prepare the aerogel fiber felt avoids the use of aqueous solvents to dissolve the aerogel powder, thus preventing damage to the aerogel structure and affecting the thermal insulation performance of the aerogel fiber felt. The room temperature thermal conductivity of the aerogel fiber felt of this invention is 0.0201 W / (mK), which is 20% lower than that of aerogel fiber felt made using pre-made aerogel powder, resulting in a significant improvement in thermal insulation performance.

[0028] 2. The composite method of the aerogel slurry and fiber felt of the present invention is as follows: the aerogel slurry is first injected into the pre-formed fiber felt by injection, and then the fiber felt is needle-punched a second time. This method has two advantages: firstly, the aerogel in the fiber felt can be more evenly distributed through injection; secondly, the present invention does not directly inject the aerogel slurry into the finished fiber felt (the needle-punched finished fiber felt has already formed and has a certain density and strength, and direct soaking or injection cannot evenly distribute the hydrophobic aerogel slurry inside the fiber felt), but rather first injects the aerogel slurry into the pre-formed fiber felt, and then performs a second needle-punching. This composite method allows for a more uniform distribution of aerogel, further improving the thermal insulation performance of the aerogel fiber felt.

[0029] 3. This invention combines the production process of aerogel slurry with the preparation process of fiber felt, thereby achieving continuous production of aerogel fiber felt. This continuous production process results in lower manufacturing costs and higher production efficiency. Furthermore, the composite fiber felt is directly conveyed to the tunnel drying line for drying, enabling a streamlined production line that significantly improves production efficiency and reduces costs.

[0030] 4. The production line equipment investment cost is much lower than that of the supercritical process, solving the problems of high investment in CO2 supercritical process equipment and high risk factor of high-temperature supercritical process, thus lowering the investment threshold for investors. Moreover, compared with the CO2 supercritical drying process, the dried product will have some residual organic solvents. The product of this invention is dried in a tunnel furnace at different temperature zones, resulting in better fire resistance. Attached Figure Description

[0031] Figure 1 This is a process flow diagram for preparing the aerogel slurry used in the aerogel fiber felt of the present invention;

[0032] Figure 2 This is a flow chart of the preparation process of the aerogel fiber felt of the present invention. Detailed Implementation

[0033] The specific embodiments of the present invention will be described in further detail below with reference to specific examples.

[0034] The numerical ranges in this invention should be understood to also specifically disclose each intermediate value between the upper and lower limits of the range. Each smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0035] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail. The terms “comprising,” “including,” “having,” “containing,” etc., as used herein are open-ended, meaning that they include but are not limited to.

[0036] Unless otherwise specified, the experimental methods used in this invention are all conventional methods.

[0037] Unless otherwise specified, all materials and reagents used in this invention can be purchased or synthesized by known methods.

[0038] In the quantitative experiments of this invention, each experiment was repeated three times, and the average value of the results was taken.

[0039] This invention provides a method for preparing aerogel fiber mat, the preparation process being as follows: Figure 1 , Figure 2 As shown, it includes the following steps:

[0040] (1) After dissolving the inorganic silicon source in desalinated water, an acid catalyst is slowly added to it and the reaction is complete to obtain sol A. Then, sol A is desalted by freezing to obtain sol B.

[0041] (2) Add alkaline catalyst and deionized water to sol B and react fully to obtain an aqueous gel;

[0042] (3) The aqueous gel obtained in step (2) is subjected to water bath aging, water washing and pulverization in sequence. Water bath aging can strengthen the internal structure of the gel, thereby improving product quality and reducing the thermal conductivity of the product. After aging, water washing removes the residual salt substances in the aqueous gel, which can prevent the thermal conductivity of the aerogel product from increasing, thereby improving product quality.

[0043] (4) Add solvent and surface modifier to the water-based gel after crushing in step (3), perform hydrophobic modification on the water-based gel, let it stand and separate into layers, and take the supernatant to obtain hydrophobic aerogel slurry.

[0044] (5) After opening, combing and laying the short fibers in sequence, the laid fiber web is pre-needled to obtain a preliminary fiber felt.

[0045] (6) After mixing the aerogel slurry and adhesive obtained in step (4) evenly, inject the mixed slurry quantitatively into the initially formed fiber felt, and then perform secondary needle punching on the initially formed fiber felt to obtain the formed fiber felt.

[0046] (7) Spray the mixed slurry obtained in step (6) onto the formed fiber felt so that the surface of the formed fiber felt is uniformly covered with aerogel slurry.

[0047] (8) After the fiber felt obtained in step (7) is continuously dried in the tunnel drying line, the aerogel fiber felt is obtained.

[0048] In specific implementation, the freezing desalination in step (1) involves cooling sol A to 0-10°C until no more crystals precipitate, filtering to remove the solid, and obtaining purified sol B. Cooling sol A allows most of the salts to precipitate, resulting in a sol containing only a very small amount of salt, thus achieving the separation and purification of the sol. The resulting solid precipitate can be collected, purified, and sold again, or directly treated as solid waste.

[0049] In specific implementations, the inorganic silicon source includes water glass, potassium silicate, or lithium silicate. The acid catalyst includes one or more of nitric acid, hydrochloric acid, phosphoric acid, or sulfuric acid. The mass concentration of the acid catalyst is 15-20%. The alkaline catalyst includes one or more of sodium hydroxide, potassium hydroxide, ammonia water with a mass concentration of 15-20%, or sodium carbonate.

[0050] In specific implementation, the mass ratio of the inorganic silicon source, acid catalyst, and alkaline catalyst is 100:100-250:0.5-2. Controlling the mass ratio of the inorganic silicon source to the acid-base catalyst within this range ensures a certain silicon content, avoiding excessively low silicon content which would lead to an increase in thermal conductivity; at the same time, it avoids excessively high silicon content, which would increase costs and cause the product to harden.

[0051] In specific implementation, the water bath aging in step (3) is carried out by standing for 6 to 20 hours under a water bath at 40 to 60°C.

[0052] In specific implementation, the solvent used in step (4) includes hexamethyldisiloxane, methanol, ethanol, n-hexane or n-heptane.

[0053] In specific implementation, the surface modifier used in step (4) includes trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane or propyltrichlorosilane.

[0054] In practice, the mass ratio of the solvent to the surface modifier is 100:1 to 10. If there is too little modifier, the modification will be insufficient. After modification and settling, some aqueous gel will remain in the lower wastewater layer, resulting in a low aerogel slurry yield and wasted costs. Conversely, if there is too much modifier, the cost will be high.

[0055] In practice, the mass ratio of the inorganic silicon source to the adhesive is 100:1 to 10. If there is too little adhesive, the bonding effect between the hydrophobic aerogel and the fiber felt will be poor, resulting in severe powder shedding; while if there is too much adhesive, the product will become hard, which is not conducive to its application, and the thermal conductivity will increase, resulting in a decrease in the product's thermal insulation performance. Therefore, the mass ratio of the inorganic silicon source to the adhesive is controlled to be 100:1 to 10.

[0056] In specific implementation, the adhesive includes epoxy resin, acrylic resin, white glue, phenolic resin, or polyurethane.

[0057] In specific implementation, the chopped fibers include one or more of glass fibers, ceramic fibers, mullite fibers, carbon fibers, basalt fibers, and high-silica fibers.

[0058] In practice, product sampling and packaging are carried out at the end of the tunnel drying line, and the packaged finished products are transferred to the warehouse for storage.

[0059] Example 1

[0060] This embodiment provides a method for preparing aerogel fiber mat, including the following steps:

[0061] (1) Mix 100kg of water glass and 100kg of desalinated water evenly, then slowly add 100kg of sulfuric acid with a mass fraction of 20% to adjust the pH to below 2 and react fully to obtain a sol; the specifications of the water glass are: modulus 3.1~3.4, Baumé degree 39.0~40.0, and silica content ≥26%.

[0062] (2) Cool the obtained sol to 5°C until no more crystals precipitate. After filtering to remove the solid, the purified sol is obtained.

[0063] (3) Add 1 kg of 20% concentrated ammonia and 19 kg of deionized water to the purified sol, adjust the pH to 5, and react to obtain an aqueous gel.

[0064] (4) The aqueous gel obtained in step (3) is placed in a 60°C water bath for 6 hours to age. The aged gel is then preliminarily crushed and washed with water to remove salt. After washing, the desalted gel is mechanically crushed.

[0065] (5) Add 500 kg of hexamethyldisiloxane and 20 kg of trimethylchlorosilane mixed solution to the pulverized gel in step (4), and stir continuously to perform hydrophobic modification on the pulverized aqueous gel. After the modification is completed, the separated liquid is the hydrophobic aerogel slurry.

[0066] (6) The chopped inorganic glass fibers are weighed according to the process conditions and then added to the opening machine for opening. The opened glass fibers are automatically transferred to the carding machine for fiber carding to fully separate the glass fibers. The carded glass fibers are automatically transferred to the web laying machine to lay the glass fibers into a continuous glass fiber web. The number of layers of the glass fiber web is adjusted according to the thickness of the needled felt, and then pre-needling is performed to obtain the pre-needled fiber felt. The main purpose of pre-needling is to make the fiber web between the layers have a certain longitudinal weaving and interlacing, initially forming the outline of the needled felt and giving it some strength.

[0067] (7) After mixing the hydrophobic aerogel slurry obtained in step (5) with 10 kg of white latex evenly, inject the mixed slurry quantitatively into the initially formed fiber felt, and then perform secondary needle punching on the initially formed fiber felt to obtain the formed fiber felt; the slurry injection process is carried out in a sealed hood filled with nitrogen to prevent the risk of explosion, combustion and other risks.

[0068] (8) Spray the mixed slurry obtained in step (7) onto the formed fiber felt so that the surface of the formed fiber felt is uniformly covered with aerogel slurry.

[0069] (9) After the fiber felt obtained in step (8) is continuously dried in the tunnel drying line, the aerogel fiber felt is obtained.

[0070] Example 2

[0071] This embodiment provides a method for preparing aerogel fiber mat, including the following steps:

[0072] (1) Mix 100kg of water glass and 100kg of water evenly, then slowly add 250kg of nitric acid with a mass fraction of 20% to adjust the pH to below 2 and react fully to obtain a sol; the specifications of the water glass are: modulus 3.1~3.4, Baumé degree 39.0~40.0, and silica content ≥26%.

[0073] (2) Cool the obtained sol to 0°C until no more crystals precipitate. After filtering to remove the solid, the purified sol is obtained.

[0074] (3) Add 0.8 kg of sodium hydroxide and 19.2 kg of deionized water to the purified sol, adjust the pH to 5, and the reaction yields an aqueous gel;

[0075] (4) The aqueous gel obtained in step (3) is placed in a 50°C water bath for 12 hours to age. The aged aqueous gel is then preliminarily crushed and washed with water to remove salt. After washing, the desalted gel is mechanically crushed.

[0076] (5) Add 500 kg of n-heptane and 15 kg of dimethyldichlorosilane mixed solution to the water-based gel after pulverization in step (4) to modify the water-based gel hydrophobically. After the modification is completed, the supernatant separated out is the hydrophobic aerogel slurry.

[0077] (6) Weigh the chopped ceramic fibers according to the process conditions, and then add them to the opening machine for opening. The opened ceramic fibers are automatically transferred to the carding machine for fiber carding, so that the ceramic fibers are fully carded. The carded ceramic fibers are automatically transferred to the web laying machine to lay the ceramic fibers into a continuous ceramic fiber web. Adjust the number of layers of the ceramic fiber web according to the thickness of the needle-punched felt, and then perform pre-needling to obtain the pre-needled fiber felt. The main purpose of pre-needling is to make the fiber web between the layers have a certain longitudinal weaving and interlacing, initially forming the outline of the needle-punched felt, and giving it some strength.

[0078] (7) After mixing the aerogel slurry obtained in step (5) with 10 kg of epoxy resin evenly, inject the mixed slurry quantitatively into the pre-formed fiber felt, and then perform a second needle punching on the pre-formed fiber felt to obtain the formed fiber felt; the slurry injection process is carried out in a sealed hood filled with nitrogen to prevent the risk of explosion, combustion and other risks.

[0079] (8) Spray the mixed slurry obtained in step (7) onto the formed fiber felt so that the surface of the formed fiber felt is uniformly covered with aerogel slurry.

[0080] (9) After the fiber felt obtained in step (8) is continuously dried in the tunnel drying line, the aerogel fiber felt is obtained.

[0081] Example 3

[0082] This embodiment provides a method for preparing aerogel fiber mat, including the following steps:

[0083] (1) Mix 100kg of water glass and 100kg of water evenly, then slowly add 150kg of nitric acid with a mass fraction of 20% to adjust the pH to below 2 and react fully to obtain a sol; the specifications of the water glass are: modulus 3.1~3.4, Baume degree 39.0~40.0, and silica content ≥26%.

[0084] (2) Cool the obtained sol to 10°C until no more crystals precipitate. After filtering to remove the solid, the purified sol is obtained.

[0085] (3) Add 1 kg of sodium hydroxide and 24 kg of deionized water to the purified sol, adjust the pH to 6, and react to obtain an aqueous gel.

[0086] (4) The aqueous gel obtained in step (3) is placed in a 40°C water bath for 20 hours to age. The aged aqueous gel is then preliminarily crushed and washed with water to remove salt. After washing, the desalted gel is mechanically crushed.

[0087] (5) Add 500 kg of n-hexane and 5 kg of methyltrichlorosilane mixed solution to the water-based gel after pulverization in step (4) to perform hydrophobic modification on the water-based gel. After the modification is completed, the supernatant separated out is the hydrophobic aerogel slurry.

[0088] (6) Weigh the chopped carbon fibers according to the process conditions, and then add them to the opening machine for opening. The opened carbon fibers are automatically transferred to the carding machine for fiber carding, so that the carbon fibers are fully carded. The carded carbon fibers are automatically transferred to the web laying machine to lay the carbon fibers into a continuous carbon fiber web. Adjust the number of layers of the carbon fiber web according to the thickness of the needle-punched felt, and then perform pre-needling to obtain pre-needled fiber felt. The main purpose of pre-needling is to make the fiber web between the layers have a certain longitudinal weaving and interlacing, initially forming the outline of the needle-punched felt, and giving it some strength.

[0089] (7) After mixing the aerogel slurry obtained in step (5) with 10 kg of phenolic resin evenly, inject the mixed slurry quantitatively into the pre-formed fiber felt, and then perform a second needle punching on the pre-formed fiber felt to obtain the formed fiber felt; the slurry injection process is carried out in a sealed hood filled with nitrogen to prevent the risk of explosion, combustion and other risks.

[0090] (8) Spray the mixed slurry obtained in step (7) onto the formed fiber felt so that the surface of the formed fiber felt is uniformly covered with aerogel slurry.

[0091] (9) After the fiber felt obtained in step (8) is continuously dried in the tunnel drying line, the aerogel fiber felt is obtained.

[0092] Table 1 shows a comparison of the room-temperature thermal conductivity of this embodiment and existing aerogel fiber felts.

[0093] Table 1 Comparison of Fiber Felt Performance

[0094] sample Thermal conductivity / W / (m·K) Fiberglass needle-punched felt 0.032 CN112522949A - Example 1 0.02418 Example 1 0.0201 Example 2 0.0211 Example 3 0.0217

[0095] As shown in Table 1, the thermal conductivity of the aerogel fiber felt prepared by the present invention is as low as 0.0201 W / (m·K) at room temperature, and its thermal insulation performance is relatively high. Compared with the aerogel fiber felt prepared using finished aerogel powder, its thermal conductivity is reduced by 20%, and its thermal insulation performance is significantly improved.

[0096] 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 the technical solutions. Those skilled in the art should understand that any modifications or equivalent substitutions to the technical solutions of the present invention without departing from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing an aerogel fiber felt, characterized in that, Includes the following steps: (1) After dissolving the inorganic silicon source in desalinated water, an acid catalyst is slowly added to it and the reaction is complete to obtain sol A. Then, sol A is desalted by freezing to obtain sol B. (2) Add alkaline catalyst and deionized water to sol B and react fully to obtain an aqueous gel; (3) The aqueous gel obtained in step (2) is subjected to water bath aging, water washing and pulverization in sequence; (4) Add solvent and surface modifier to the water-based gel after crushing in step (3), perform hydrophobic modification treatment on the water-based gel, let it stand and separate into layers, and take the supernatant to obtain hydrophobic aerogel slurry. (5) After opening, combing and laying the short fibers in sequence, the laid fiber web is pre-needled to obtain a preliminary fiber felt. (6) After mixing the hydrophobic aerogel slurry and adhesive obtained in step (4) evenly, inject the mixed slurry quantitatively into the initially formed fiber felt, and then perform secondary needle punching on the initially formed fiber felt to obtain the formed fiber felt. (7) Spray the mixed slurry obtained in step (6) onto the formed fiber felt so that the surface of the formed fiber felt is uniformly covered with hydrophobic aerogel slurry. (8) After drying the fiber felt obtained in step (7), aerogel fiber felt is obtained.

2. The method for preparing aerogel fiber felt according to claim 1, characterized in that, In step (1), the freezing desalination is performed by cooling sol A to 0-10°C until no more crystals precipitate, filtering to remove the solid, and obtaining sol B.

3. The method for preparing aerogel fiber felt according to claim 1, characterized in that, In step (6), the hydrophobic aerogel slurry and adhesive are mixed at a mass ratio of inorganic silicon source to adhesive of 100:1 to 10.

4. The method for preparing aerogel fiber felt according to claim 1, characterized in that, The mass ratio of the inorganic silicon source, acid catalyst, and basic catalyst is 100:100-250:0.5-2.

5. The method for preparing aerogel fiber felt according to claim 1, characterized in that, In step (4), the mass ratio of solvent to surface modifier is 100:1 to 10.

6. The method for preparing aerogel fiber felt according to claim 1, characterized in that, In step (4), the solvent includes hexamethyldisiloxane, methanol, ethanol, n-hexane or n-heptane.

7. The method for preparing aerogel fiber felt according to claim 1, characterized in that, In step (4), the surface modifier includes trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane or propyltrichlorosilane.

8. The method for preparing aerogel fiber felt according to claim 1, characterized in that, In step (8), the drying method is to transfer the fiber felt obtained in step (7) to the tunnel drying line for continuous drying to obtain aerogel fiber felt.

9. The method for preparing aerogel fiber felt according to claim 1, characterized in that, In step (3), the water bath aging is carried out by standing for 6 to 20 hours under a water bath at 40 to 60°C.

10. The method for preparing aerogel fiber felt according to claim 1, characterized in that, The adhesive used in step (6) includes epoxy resin, acrylic resin, white glue, phenolic resin or polyurethane.

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