A method for preparing a cement aerogel composite

Abstract

This invention discloses a method for preparing cement aerogel composite materials. The "silane anchoring-nucleation shell-calcium salt fixation" synergistic modification process and single-component product provided by this invention fundamentally solves the interfacial compatibility problem between hydrophobic aerogel and cement matrix by constructing a strong and tough interfacial reaction layer with a smooth modulus transition. It achieves efficient integrated fusion of the aerogel insulation phase and the cement structural phase, and successfully transforms the complex multi-component compounding process that must be completed on-site in traditional processes into standardized prefabrication production in the factory. The final single-component dry powder product completely eliminates the dependence on on-site weighing, sequential feeding, and step-by-step mixing. During construction, only water needs to be added in proportion and mixed in one step to form a homogeneous mortar. While ensuring excellent thermal insulation performance, it achieves a comprehensive improvement in mechanical strength and interfacial reliability, with cohesive failure as the main failure mode, thus enabling "ready-to-use" operation.

Description

Technical Field

[0001] This invention relates to the field of composite aerogel materials technology, and in particular to a method for preparing cement aerogel composite materials. Background Technology

[0002] Aerogels, due to their extremely low thermal conductivity, high porosity, and lightweight properties, are considered ideal materials for improving building insulation performance. Introducing aerogels into cementitious matrices to prepare composite materials that combine high-efficiency thermal insulation with a certain structural load-bearing capacity is an important research direction in the field of building energy conservation. However, significant differences in the physicochemical properties between hydrophobic silica aerogels and hydrophilic cementitious matrices have led to a long-standing technical bottleneck.

[0003] To overcome this difference, traditional processes generally adopt a "separate storage and on-site mixing" model. This model requires aerogel particles, cement, aggregates, and various polymer additives to be packaged, stored, and transported separately as independent components. During construction, the precise weighing, sequential addition, and step-by-step mixing of multiple components must be completed on-site. Typical publicly available technologies (such as CN202311267657.X) embody this complex process of "on-site component assembly." This model has inherent drawbacks: First, the process is cumbersome and heavily reliant on on-site conditions and manual operation, resulting in low construction efficiency and difficulty in ensuring quality uniformity. Second, and most critically, this model is essentially a "physical mixing" process. Hydrophobic aerogels are difficult to disperse evenly in hydrophilic slurries and are prone to agglomeration. The lack of effective chemical bonding and physical interlocking between the aerogel surface and cement hydration products creates a transition zone with weak mechanical properties at the interface.

[0004] These defective interfaces become stress concentration points and crack propagation sources in composite materials, resulting in low tensile bond strength, limited improvement in compressive strength, and failure modes primarily involving interfacial delamination. Furthermore, multi-component management increases overall costs, and aerogels are prone to moisture absorption and aggregation during storage and transportation, further impairing long-term durability.

[0005] Therefore, existing technologies have long been hampered by the contradiction between achieving "high-performance materials" and "simple and reliable construction." The key questions are: how to fundamentally improve the compatibility of the aerogel-cement interface, achieve integrated improvement in material performance while completely eliminating reliance on complex on-site mixing processes, and how to ensure stable performance while maintaining immediate usability?

[0006] Therefore, how to solve the above problems is an urgent technical challenge. Summary of the Invention

[0007] In view of this, the purpose of this invention is to provide a method for preparing cement aerogel composite materials.

[0008] For the purposes described above, the present invention provides A method for preparing cement aerogel composite material includes the following steps: S1: The original hydrophobic silica aerogel particles are dried by hot air and sieved to obtain pre-dried graded aerogel particles; the original aerogel feed amount is corrected with the target mass of the final interface reaction layer modified aerogel particles and the coating weight gain rate Δm reaching the set value as the closed-loop control target. S2: The silane coupling agent is pre-hydrolyzed in an acidic ethanol / water solution to obtain a silane pre-hydrolyzed solution; the pre-hydrolyzed solution is atomized and sprayed onto the surface of the particles obtained in S1, and then dried and cured to obtain intermediate aerogel particles with an interface anchoring layer. S3: Nano-silica sol is atomized and sprayed onto the surface of the particles obtained in S2, followed by spraying with 0.10 mol / L calcium nitrate solution, and then dried and cured. By adjusting the amount of raw materials fed and the amount of sol sprayed, the coating weight gain rate Δm is controlled to be 3.5%-4.5% to obtain the interface reaction layer - aerogel particles. S4: In a dry environment, cement, mineral admixtures, and fine aggregates are premixed; then cellulose ether, water-reducing agent, water-repellent agent, shrinkage reducing agent, defoamer, and anti-caking agent are premixed with some of the aforementioned dry powders and added to the main mixer; then a premix of redispersible latex powder and gypsum is added; then lightweight aggregates are added; finally, the interfacial reaction layer-aerogel particles obtained in S3 and the premixed fibers are added in batches, and the mixture is low-shear mixed to obtain a single-component terminal dry powder mixture; S5: After the mixture obtained in S4 is sieved, matured, and tested to ensure it passes inspection, it is sealed and packaged to obtain the single-component aerogel cement-based dry powder product.

[0009] Furthermore, in step S1, the hot air drying temperature is 75°C until the moisture content is ≤0.5%; the sieving process uses a vibrating screen to remove fine powder and large particle agglomerates.

[0010] Furthermore, in step S2, the silane coupling agent is selected from silane coupling agents, aminosilane coupling agents, or epoxysilane coupling agents; the mass ratio of ethanol to water in the acidic ethanol / water solution is 90:10, and the pH is adjusted to 4.5 using glacial acetic acid; the pre-hydrolysis is carried out for 20 minutes with stirring at 400 rpm; the atomized spraying is carried out in a roller coating machine under tumbling conditions at 15 rpm for 20 minutes; and the drying and curing are carried out at 70°C for 90 minutes.

[0011] Furthermore, in step S3, the solid content of the nano-silica sol is 20%; the atomization spraying rate of the nano-silica sol is 1.0 kg / min; after spraying the calcium nitrate solution, the step further includes spraying an aluminum nitrate solution with a concentration of 0.01-0.03 mol / L.

[0012] Furthermore, in step S4, the cement is ordinary silicate cement; the mineral admixture includes slag powder, calcined clay, limestone powder, and optionally microsilica powder; the fine aggregate is fine quartz sand; and the lightweight aggregate includes expanded perlite and hollow glass microspheres.

[0013] Furthermore, based on the preparation of 200 parts by weight of interface reaction layer-aerogel particles, the proportions of other materials in step S4 are as follows: 280 parts of ordinary silicate cement, 120 parts of slag powder, 80 parts of calcined clay, 59-60 parts of limestone powder, 18 parts of fine quartz sand, 132-140 parts of expanded perlite, 50 parts of hollow glass microspheres, 28-35 parts of redispersible latex powder, 1.8-2.0 parts of hydroxypropyl methylcellulose, 8 parts of gypsum, 1.2 parts of polycarboxylate superplasticizer powder, 0.3 parts of starch ether, 3.0 parts of hydrophobic and moisture-resistant powder, 7.0 parts of shrinkage reducing agent powder, 0.5 parts of powder defoamer, 0.2 parts of anti-caking agent, and 2.0-2.5 parts of fiber; the amount of microsilica powder added is 0-4 parts.

[0014] Further, the specific mixing process in step S4 is as follows: First, mix cement, mineral admixtures, and fine quartz sand at 40 rpm for 3 minutes; then, premix hydroxypropyl methylcellulose, starch ether, polycarboxylate superplasticizer powder, powdered defoamer, shrinkage reducing agent powder, water-repellent and moisture-resistant powder, and anti-caking additive with 15 kg of dry powder taken from the main mixer for 1 minute, and then return all of it to the main mixer and continue mixing for 2 minutes; next, premix redispersible latex powder and gypsum for 30 seconds and then add them to the main mixer and mix for 1 minute; then add expanded perlite and hollow glass microspheres and mix at 25 rpm with low shear for 90 seconds; finally, add the interface reaction layer - aerogel particles in two batches and mix at 25 rpm with low shear for 2 minutes, while simultaneously adding the fiber and 10 kg of dry powder taken from the fine quartz sand after premixing for 30 seconds, and continue mixing for 60 seconds.

[0015] Furthermore, in step S5, the sieving is performed through an 8-10 mesh vibrating screen; the maturation is carried out in a sealed drying room at a temperature of 25°C and a relative humidity of ≤60% for 12 hours; and the moisture content of the finished product is tested to be ≤0.5%.

[0016] Furthermore, a method for preparing cement aerogel composite materials yields a single-component aerogel cement-based dry powder.

[0017] Furthermore, when using it, add 0.55 times the weight of the dry powder with mixing water, and after stirring, a workable mortar can be formed. The product has a 28-day dry thermal conductivity of no more than 0.080 W / (m·K), a 28-day compressive strength ≥4.0 MPa, and a 28-day tensile bond strength ≥0.62 MPa. The beneficial effects of this invention are: The "silane anchoring-nucleation shell-calcium salt point consolidation" synergistic modification process and single-component product provided by this invention fundamentally solves the interfacial compatibility problem between hydrophobic aerogel and cement matrix by constructing a strong and tough interfacial reaction layer with a smooth modulus transition. This achieves efficient integrated fusion of the aerogel insulation phase and the cement structural phase, and successfully transforms the complex multi-component compounding process that must be completed on-site in traditional processes into standardized prefabrication in a factory. The resulting single-component dry powder product completely eliminates the reliance on on-site weighing, sequential feeding, and step-by-step mixing. During construction, only one step of mixing with water according to the ratio is required to form a homogeneous mortar. While ensuring excellent thermal insulation performance, it achieves a comprehensive improvement in mechanical strength and interfacial reliability, with cohesive failure as the primary failure mode. Thus, in a "ready-to-use" manner, it simultaneously overcomes the two core bottlenecks that have long restricted the large-scale application of this technology: "weak interfacial bonding" and "complex on-site construction," providing a system solution with uniform and stable performance and convenient and efficient construction. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0019] Example 1 A method for preparing cement aerogel composite material includes the following steps: S1: Weigh 193.2 kg of the original hydrophobic silica aerogel particles, place them in a 75°C hot air dryer for 3 hours until the moisture content is ≤0.5%, and after removing them from the oven, cool them in a sealed drying room for 45 minutes. Remove fine powder and large particle agglomerates by a vibrating screen to obtain pre-dried graded aerogel particles. With the final result of 200.0 kg of interface reaction layer modified aerogel particles and the coating weight gain Δm reaching the set value as the closed-loop control target, the amount of original aerogel feed and the amount of subsequent sol spraying are corrected in the process.

[0020] S2: Weigh 1.93 kg of silane coupling agent and add it to 40.0 kg of a mixed solvent of ethanol / water in a mass ratio of 90 / 10. Adjust the pH of the system to 4.5 with glacial acetic acid and stir at 400 rpm for 20 minutes to pre-hydrolyze the silane to obtain a silane pre-hydrolyzed solution. After the pre-hydrolyzed solution is allowed to stand at 25 degrees Celsius for 5 minutes to mature, add the aerogel particles obtained in S1 to a roller coating machine. Under the condition of tumbling at 15 rpm, spray the hydrolyzed solution with compressed air atomization for 20 minutes, then dry and cure at 70 degrees Celsius for 90 minutes, and cool in a sealed environment for 30 minutes to obtain intermediate aerogel particles with an interface anchoring layer.

[0021] S3: Take 24.2 kg of nano-silica sol with a solid content of 20%, and spray it continuously for 24.2 minutes at an atomization spraying rate of 1.0 kg / min on the surface of the particles obtained in S2 under the condition of 15 rpm of roller coating machine. During the spraying process, the particles are continuously tumbled. After the spraying is completed, the particles are tumbled for another 15 minutes. Then, spray 10.0 kg of 0.10 mol / L calcium nitrate solution and tumble for 3 minutes. After the spraying is completed, place the material at 75 degrees Celsius to dry and cure for 2 hours, and then cool it in a sealed environment for 45 minutes. Control the coating weight gain rate Δm to be 3.5% to obtain 200.0 kg of interfacial reaction layer - aerogel particles.

[0022] S4: In a dry-mixing environment with a temperature of 25 degrees Celsius and a relative humidity of ≤60%, 280 kg of ordinary silicate cement, 120 kg of slag powder, 80 kg of calcined clay, 60 kg of limestone powder, and 18 kg of fine quartz sand are sealed and left to stand for 2 hours with a moisture content controlled to ≤0.5%. The above materials are then added to a dry powder mixer and mixed at 40 rpm for 3 minutes. Separately, 1.8 kg of hydroxypropyl methylcellulose, 0.3 kg of starch ether, 1.2 kg of polycarboxylate superplasticizer powder, 0.5 kg of powdered defoamer, 7.0 kg of shrinkage reducing agent powder, 3.0 kg of water-repellent and moisture-resistant powder, and 0.2 kg of anti-caking agent are added to the aforementioned mixture. After premixing the 15 kg of dry powder for 1 minute, it was all returned to the main mixer and mixed for another 2 minutes. Then, 28 kg of redispersible latex powder and 8 kg of gypsum were premixed for 30 seconds and added to the main mixer, and mixed for 1 minute. Subsequently, 140 kg of expanded perlite and 50 kg of hollow glass microspheres were added and mixed at 25 rpm with low shear for 90 seconds. Finally, 200 kg of the interface reaction layer-aerogel particles obtained from S3 were added in two batches and mixed at 25 rpm with low shear for 2 minutes. At the same time, 2.0 kg of fiber and 10 kg of dry powder taken from fine quartz sand were premixed for 30 seconds and added, and mixed for another 60 seconds to obtain a single-component terminal dry powder mixture.

[0023] S5: The single-component terminal dry powder mixture obtained in S4 is sieved and granulated through an 8-10 mesh vibrating screen, and then placed in a drying room at 25 degrees Celsius and relative humidity ≤60% for 12 hours of sealed curing. After curing, the moisture content of the finished product is tested to be ≤0.5%, and the loose density and flowability are retested. After meeting the internal control standards, it is sealed and packaged in a moisture-proof composite film bag to obtain a single-component aerogel cement-based thermal insulation and fireproof interior wall terminal dry powder product.

[0024] Example 2 The steps differ from those in Example 1 in that: In S1, the original amount of hydrophobic silica aerogel particles is 191.4 kg.

[0025] In S2, 2.87 kg of aminosilane coupling agent was weighed for pre-hydrolysis and spraying.

[0026] In S3, 30.0 kg of nano-silica sol with a solid content of 20% was sprayed, and the coating weight gain rate Δm was controlled to be 4.5%.

[0027] In S4, the weighing amounts of each material are as follows: 280 kg of ordinary silicate cement, 120 kg of slag powder, 80 kg of calcined clay, 59.7 kg of limestone powder, 18 kg of fine quartz sand, 2.0 kg of hydroxypropyl methylcellulose, 35 kg of redispersible latex powder, 132.6 kg of expanded perlite, and 2.5 kg of fiber. The types and amounts of other materials, as well as all process parameters (such as temperature, time, and rotation speed), are the same as in Example 1.

[0028] Example 3 The steps differ from those in Example 1 in that: In S1, the original amount of hydrophobic silica aerogel particles is 192.4 kg.

[0029] In S2, 2.31 kg of epoxy silane coupling agent was weighed for pre-hydrolysis and spraying.

[0030] In S3, 26.0 kg of nano-silica sol with a solid content of 20% was sprayed; after spraying calcium nitrate solution, 5.0 kg of 0.02 mol / L aluminum nitrate solution was sprayed by dilution and atomization and rolled for 3 minutes; the coating weight gain rate Δm was controlled to be 4.0%.

[0031] In S4, the weighing amounts of each material are as follows: 280 kg of ordinary silicate cement, 120 kg of slag powder, 80 kg of calcined clay, 59.8 kg of limestone powder, 18 kg of fine quartz sand, 4.0 kg of microsilica powder, 2.0 kg of hydroxypropyl methylcellulose, 32 kg of redispersible latex powder, 132 kg of expanded perlite, and 2.0 kg of fiber. The types and amounts of the remaining materials and all process parameters are the same as in Example 1.

[0032] Comparative Example 1 The difference between the steps and those in Example 1 is that in S1, 200.0 kg of the original hydrophobic silica aerogel particles are directly weighed, dried and sieved to obtain 200.0 kg of pre-dried graded aerogel particles, which are then directly used for subsequent compounding.

[0033] In S4, except that the added aerogel particles are replaced with 200.0 kg of the above-mentioned unmodified hydrophobic aerogel particles, the formulation, dosage and mixing process of the other materials are exactly the same as in Example 1.

[0034] Step S5 is the same as in Example 1.

[0035] It omits all steps S2 (silane coupling agent anchoring treatment) and S3 (nano SiO2 sol spraying and calcium nitrate spot treatment).

[0036] Comparative Example 2 The difference between the steps and those in Example 1 is that only the silane anchoring treatment in S2 is performed, and the nucleation shell construction and calcium salt fixation steps in S3 are omitted.

[0037] In S1, approximately 198.1 kg of raw aerogel particles were weighed and corrected to obtain 200.0 kg of modified particles.

[0038] Step S2 is the same as in Example 1, yielding aerogel particles modified only with a silane anchoring layer.

[0039] In S3, without spraying the sol and calcium salt solution, the particles obtained in S2 were dried and cured at 75°C for 2 hours, resulting in a coating weight gain rate Δm of approximately 1.0%, yielding 200.0 kg of silane anchoring layer modified aerogel particles.

[0040] In S4, except that the added aerogel particles are replaced with the above-mentioned silane anchoring layer modified aerogel particles, the formulation, dosage and mixing process of the other materials are exactly the same as in Example 1.

[0041] Step S5 is the same as in Example 1.

[0042] Comparative Example 3 The steps differ from those in Example 1 in that: In S1, approximately 193.2 kg of raw aerogel particles were weighed, and calibration was performed with the goal of ultimately obtaining 200.0 kg of modified particles and achieving the required Δm.

[0043] Step S2 is skipped; the granules obtained in S1 are placed directly into the roller coating machine for later use.

[0044] In S3, 24.2 kg of nano-SiO2 sol with a solid content of 20% was sprayed onto the surface of the above particles, followed by spraying 10.0 kg of 0.10 mol / L calcium nitrate solution, and drying and curing at 75°C. The coating weight gain rate Δm was controlled to be 3.5%, resulting in 200.0 kg of nucleation-shell modified aerogel particles.

[0045] In S4, except that the added aerogel particles are replaced with the above-mentioned nucleation-shell modified aerogel particles, the formulation, dosage and mixing process of the other materials are exactly the same as in Example 1.

[0046] Step S5 is the same as in Example 1.

[0047] In the test examples, 10.0 kg of the single-component terminal dry powder products obtained in Examples 1–3 and Comparative Examples 1–3 were taken as a group of test samples. In an environment with a temperature of 25°C and a relative humidity of ≤60%, mixing water was weighed at 0.55 times the mass of the dry powder. The water was added to the mixing bucket first, and then the dry powder was added in batches. The mixture was stirred at 300 rpm for 2 minutes until uniform. After standing and maturing for 3 minutes, it was stirred at 300 rpm for 1 minute to obtain a workable mortar. The obtained mortar was used to prepare nano-indentation interface slice samples: 20 mm × 20 mm × 20 mm molds were used for molding. After filling, the samples were lightly vibrated and the surface was scraped flat. Each group had no less than 3 samples. When molding, samples containing typical aerogel particles were selected first and numbered and marked on the side.

[0048] After molding, the samples were covered with a PE film and cured for 24 hours at 25°C and 60% relative humidity. After demolding, they were cured under the same conditions for 28 days. After 28 days, the samples were sliced ​​and polished, and nanoindentation tests were performed: the samples were cut into 5–10 mm slices along the cross-section containing aerogel particles, and impregnated and cured with low-viscosity epoxy resin under vacuum; they were then wet-ground with 400#, 800#, 1200#, and 2000# sandpaper in sequence, and then polished to a mirror finish with 3 μm and 1 μm diamond suspensions and 0.05 μm silica. The boundaries of the aerogel particles were located under an optical microscope, and a Berkovich indenter was used to perform a loading-holding-unloading test with a maximum load of 3 mN (loading for 10 s, holding for 5 s, and unloading for 10 s). Using the boundary of the aerogel particles as the zero point, line scan indentation points are laid out radially towards the cement matrix, with a distance range of 0–200 μm and an indentation point spacing of 5–10 μm. Each line has no less than 30 indentation points, and each sample has no less than 3 line scans. Simultaneously, at least 20 matrix array indentation points are laid out at a distance away from the interface (≥300 μm from the interface). The elastic modulus E and hardness H of each indentation point are recorded and calculated.

[0049] The modulus valley value Emin, valley width w, interfacial weakening degree ΔE, and interfacial smoothness index G obtained by nanoindentation were used as the core data for comparative verification of the degree of fusion between aerogel and cement. The specific test results are shown in the table below: Table 1: Data on the Fusion Performance of Nanoindentation Interface ; Where ΔE = Em - Emin; R = (Emin / Em) × 100%; w is the width of the continuous interval that satisfies E < 0.80×Em; G is the average absolute value of the modulus gradient in the 0–100 μm interval of the interface. The smaller the value, the smoother the interface transition.

[0050] Table 2: Three core performance indicators of terminal products (28 days) ; Data analysis, as shown in Table 1, reveals that the interfacial reaction layer-aerogel particles of Examples 1–3 of this invention, after synergistic modification via "silane anchoring + nucleation shell + calcium salt fixation," exhibit significantly optimized interfacial fusion characteristics in nanoindentation testing. Specifically, the modulus valley value E_min is significantly increased (16.5–18.0 GPa in Examples 1–3, compared to only 9.0 GPa in Comparative Example 1); the valley width w is significantly narrowed (28–35 μm in Examples 1, compared to 95 μm in Comparative Example 1); the interfacial weakening degree ΔE is significantly reduced (6.5–8.0 GPa in Examples 1, compared to 15.0 GPa in Comparative Example 1); and the interfacial smoothness index G is significantly decreased (0.10–0.12 GPa·μm in Examples 1). -1 Comparative Example 1 has a strength of 0.25 GPa·μm. -1 This indicates that a strong and tough interface with continuous modulus transition and significantly reduced weak areas is formed between the modified aerogel particles and the cement matrix, effectively avoiding stress concentration. Although the indicators of Comparative Example 2 (silane anchoring only) and Comparative Example 3 (nucleation shell only) are better than those of Comparative Example 1 (unmodified), they are all inferior to those of Example 1, confirming the necessity of synergistic modification of the two.

[0051] Based on the macroscopic performance data in Table 2, the improved interface fusion effect directly translates into a comprehensive improvement in the overall performance of the end product. Under the premise of essentially equivalent thermal insulation performance (λ = 0.078–0.080 W / (m·K)), the 28-day compressive strength (4.0–4.5 MPa) and 28-day tensile bond strength (0.62–0.85 MPa) of the examples are significantly higher than those of the comparative examples. Crucially, the failure mode of the examples is predominantly cohesive failure, which perfectly matches the micromechanical characteristics of interface strengthening (high E_min, small ΔE) and smooth interface transition (small G) shown in Table 1, indicating that the aerogel-cement interface has transformed from a "weak link" to a "reinforcing node." In contrast, comparative examples 1–3, due to poor interface fusion, exhibit lower bond strength and a failure mode primarily characterized by interface failure.

[0052] Conclusion: The data on the mechanical properties of the nanoindentation micro-interface (Table 1) and the macroscopic core properties (Table 2) corroborate each other, jointly demonstrating that the reactive interfacial layer (RIL) modification technology provided by this invention successfully solves the compatibility problem between hydrophobic aerogel and cement matrix by constructing a strong and smoothly transitioning micro-interface, thereby preparing a single-component aerogel cement-based terminal dry powder product with excellent thermal insulation, structural load-bearing capacity and high adhesion performance.

[0053] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in the details for the sake of brevity.

[0054] This invention is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for preparing cement aerogel composite material, characterized in that, Includes the following steps: S1: The original hydrophobic silica aerogel particles are dried by hot air and sieved to obtain pre-dried graded aerogel particles; the original aerogel feed amount is corrected with the target mass of the final interface reaction layer modified aerogel particles and the coating weight gain rate Δm reaching the set value as the closed-loop control target. S2: The silane coupling agent is pre-hydrolyzed in an acidic ethanol / water solution to obtain a silane pre-hydrolyzed solution; the pre-hydrolyzed solution is atomized and sprayed onto the surface of the particles obtained in S1, and then dried and cured to obtain intermediate aerogel particles with an interface anchoring layer. S3: Nano-silica sol is atomized and sprayed onto the surface of the particles obtained in S2, followed by spraying with 0.10 mol / L calcium nitrate solution, and then dried and cured. By adjusting the amount of raw materials fed and the amount of sol sprayed, the coating weight gain rate Δm is controlled to be 3.5%-4.5% to obtain the interface reaction layer - aerogel particles. S4: In a dry environment, cement, mineral admixtures, and fine aggregates are premixed; then cellulose ether, water-reducing agent, water-repellent agent, shrinkage reducing agent, defoamer, and anti-caking agent are premixed with some of the aforementioned dry powders and added to the main mixer; then a premix of redispersible latex powder and gypsum is added; then lightweight aggregates are added; finally, the interfacial reaction layer-aerogel particles obtained in S3 and the premixed fibers are added in batches, and the mixture is low-shear mixed to obtain a single-component terminal dry powder mixture; S5: After the mixture obtained in S4 is sieved, matured, and tested to ensure it passes inspection, it is sealed and packaged to obtain the single-component aerogel cement-based dry powder product.

2. The method for preparing a cement aerogel composite material according to claim 1, characterized in that, In step S1, the hot air drying temperature is 75°C until the moisture content is ≤0.5%; the sieving process uses a vibrating screen to remove fine powder and large particle agglomerates.

3. The method for preparing a cement aerogel composite material according to claim 1, characterized in that, In step S2, the silane coupling agent is selected from silane coupling agents, aminosilane coupling agents, or epoxysilane coupling agents; the mass ratio of ethanol to water in the acidic ethanol / water solution is 90:10, and the pH is adjusted to 4.5 using glacial acetic acid; the pre-hydrolysis is carried out for 20 minutes with stirring at 400 rpm; the atomized spraying is carried out in a roller coating machine under tumbling conditions at 15 rpm for 20 minutes. The drying and curing process is carried out at 70°C for 90 minutes.

4. The method for preparing a cement aerogel composite material according to claim 1, characterized in that, In step S3, the solid content of the nano-silica sol is 20%; the atomization spraying rate of the nano-silica sol is 1.0 kg / min; after spraying the calcium nitrate solution, the step further includes spraying an aluminum nitrate solution with a concentration of 0.01-0.03 mol / L.

5. The method for preparing a cement aerogel composite material according to claim 1, characterized in that, In step S4, the cement is ordinary Portland cement; the mineral admixture includes slag powder, calcined clay, limestone powder, and optionally microsilica powder; the fine aggregate is fine quartz sand; and the lightweight aggregate includes expanded perlite and hollow glass microspheres.

6. The method for preparing a cement aerogel composite material according to claim 5, characterized in that, Based on the preparation of 200 parts by weight of interface reaction layer-aerogel particles, the proportions of other materials in step S4 are as follows: 280 parts of ordinary silicate cement, 120 parts of slag powder, 80 parts of calcined clay, 59-60 parts of limestone powder, 18 parts of fine quartz sand, 132-140 parts of expanded perlite, 50 parts of hollow glass microspheres, 28-35 parts of redispersible latex powder, 1.8-2.0 parts of hydroxypropyl methylcellulose, 8 parts of gypsum, 1.2 parts of polycarboxylate superplasticizer powder, 0.3 parts of starch ether, 3.0 parts of hydrophobic and moisture-resistant powder, 7.0 parts of shrinkage reducing agent powder, 0.5 parts of powder defoamer, 0.2 parts of anti-caking agent, and 2.0-2.5 parts of fiber; the amount of silica powder added is 0-4 parts.

7. The method for preparing a cement aerogel composite material according to claim 1, characterized in that, The specific mixing process in step S4 is as follows: First, mix cement, mineral admixtures, and fine quartz sand at 40 rpm for 3 minutes; then, premix hydroxypropyl methylcellulose, starch ether, polycarboxylate superplasticizer powder, powdered defoamer, shrinkage reducing agent powder, water-repellent and moisture-resistant powder, and anti-caking additive with 15 kg of dry powder taken from the main mixer for 1 minute, and then return all of it to the main mixer and continue mixing for 2 minutes; next, premix redispersible latex powder and gypsum for 30 seconds and then add them to the main mixer and mix for 1 minute; then add expanded perlite and hollow glass microspheres and mix at 25 rpm with low shear for 90 seconds; finally, add the interface reaction layer - aerogel particles in two batches and mix at 25 rpm with low shear for 2 minutes, while simultaneously adding the fiber and 10 kg of dry powder taken from the fine quartz sand after premixing for 30 seconds, and continue mixing for 60 seconds.

8. The method for preparing a cement aerogel composite material according to claim 1, characterized in that, In step S5, the sieving is performed through an 8-10 mesh vibrating screen; the maturation is carried out in a sealed drying room at a temperature of 25°C and a relative humidity of ≤60% for 12 hours; and the moisture content of the finished product is tested to be ≤0.5%.

9. A single-component aerogel cement-based dry powder prepared by the method for preparing a cement aerogel composite material according to any one of claims 1-8.

10. The single-component aerogel cement-based dry powder according to claim 9, characterized in that, When using it, add 0.55 times the mass of dry powder to the mixing water, and after stirring, it can form a workable mortar; the product has a 28-day dry thermal conductivity of no more than 0.080 W / (m·K), a 28-day compressive strength of ≥4.0 MPa, and a 28-day tensile bond strength of ≥0.62 MPa.