Preparation method of high-temperature-resistant low-heat-conductivity-coefficient composite high-strength thermal insulation coating

Abstract

The invention relates to the field of high-temperature-resistant inorganic composite heat preservation and insulation materials, and particularly discloses a preparation method of a high-temperature-resistant low-heat-conductivity-coefficient composite high-strength heat preservation and insulation coating. The preparation method comprises the following steps: firstly, fully mixing and stirring an inorganic light heat-insulating material, fibers, a surfactant and water to form uniform slurry; and secondly, adding an exciting agent and powder with exciting activity into the slurry, and uniformly dispersing at a high speed to obtain the required coating. By adding the excitant and the powder with excitation activity, geopolymer gel with a three-dimensional network structure is formed in the curing process of the coating, so that the mechanical strength and the bonding strength of the material are remarkably improved, and the material has excellent compression resistance and bonding performance while keeping an extremely low heat conductivity coefficient. The coating disclosed by the invention shows remarkable advantages and wide application prospects in the fields of metallurgy, chemical industry, petrifaction, nuclear energy and the like.

Description

Technical Field

[0001] The present invention belongs to the field of high-temperature composite material thermal insulation, and specifically relates to a preparation and use method of a high-temperature resistant, low thermal conductivity composite high-strength thermal insulation coating. Background Art

[0002] In high-temperature industrial equipment (such as metallurgical kilns, chemical reactors, nuclear energy systems) and aerospace fields, thermal insulation materials play a decisive role in energy consumption control and safe operation. However, the existing material system faces two irreconcilable performance contradictions: First, although traditional insulation materials (such as aluminum silicate fiber and microporous calcium silicate) have a low thermal conductivity (0.03-0.06W / (m·K)) at room temperature, under high-temperature conditions, the thermal conductivity is significantly degraded due to the enhanced gas convection and the dominance of infrared radiation heat transfer. For example: the thermal conductivity of aluminum silicate fiber rises to 0.25W / (m·K) at 1000℃ (an increase of >700%), and the thermal conductivity of microporous calcium silicate reaches 0.18W / (m·K) at 800℃ (4.5 times the room temperature value). This degradation directly causes the heat loss rate of industrial kilns to soar from the design value of 8% to more than 22%, seriously restricting the realization of the "dual carbon" goals. Secondly, ultra-low conductivity materials such as aerogels (thermal conductivity coefficient <0.03W / (m·K) at 1000℃) have been developed to suppress high-temperature heat transfer. However, due to the intrinsic brittleness of the nanoporous structure, they have almost no compressive strength and bonding strength. Therefore, there is an urgent need to develop thermal insulation materials that have compressive strength, bonding strength, and extremely low thermal conductivity at high temperatures.

[0003] Geopolymers are inorganic polymer materials formed with a siliceous-aluminous matrix (such as metakaolin and fly ash) under the action of an activator. Currently, no technology has been found to improve the mechanical properties of lightweight inorganic thermal insulation materials, imparting excellent compressive strength and adhesive strength while also maintaining extremely low thermal conductivity at high temperatures. Summary of the Invention

[0004] To address the shortcomings of the prior art, the present invention provides a method for preparing and using a high-temperature-resistant, low-thermal-conductivity composite high-strength thermal insulation coating. By improving inorganic lightweight insulation materials with geopolymers, the present invention produces a high-temperature-resistant, low-thermal-conductivity composite high-strength thermal insulation coating, providing a solution for achieving energy conservation and emission reduction in high-temperature equipment.

[0005] In order to achieve the above object, the technical solution of the present invention is as follows:

[0006] Step 1: Mix an inorganic lightweight thermal insulation material, fiber, surfactant, and water to obtain an inorganic lightweight thermal insulation slurry; the weight ratio of the inorganic lightweight thermal insulation material, fiber, surfactant, and water is 100-200:1-50:0-30:200-500.

[0007] Step 2: stirring the slurry in step 1 at a specific temperature for a certain period of time to obtain a uniformly dispersed inorganic lightweight insulating slurry;

[0008] Step 3: Add the powder with excitation activity and the stimulator to the inorganic lightweight thermal insulation slurry prepared in step 2 to obtain a mixed slurry; the ratio of the powder with excitation activity, the stimulator, and the inorganic lightweight thermal insulation slurry is: 10-100: 5-120: 300-700.

[0009] Step 4: Stir the mixed slurry in step 3 at a specific temperature for a certain period of time to obtain a uniformly dispersed high-temperature resistant, low thermal conductivity composite high-strength thermal insulation coating.

[0010] Furthermore, the inorganic lightweight insulation material described in step 1 includes rock wool, glass wool, aluminum silicate fiber wool, expanded perlite, vitrified microspheres, expanded vermiculite, diatomaceous earth, fly ash floating beads, hollow glass microspheres, aerogel, microporous calcium silicate, and nanoporous alumina. Any one or any combination can be selected when used.

[0011] Furthermore, the fibers described in step 1 include silicon carbide fibers, alumina fibers, potassium titanate fibers, glass fibers, ceramic fibers, steel fibers, basalt fibers, hafnium carbide-coated carbon fibers, zirconium oxide fibers, silicon nitride fibers, yttrium aluminum garnet fibers, and aluminum silicate fibers, and any one or any combination thereof can be selected for use.

[0012] Furthermore, the surfactant described in step 1 includes hydroxyethyl cellulose, polyether F127, polypropylene adipate, alkylphenol polyoxyethylene ether, fatty acid polyoxyethylene ester, alkylbenzene sulfonate (ABS), alkyl sulfonate, fatty alcohol phosphate salt, fatty alcohol polyoxyethylene ether sulfate (AES), hexadecyltrimethylammonium bromide, carboxybetaine, sulfobetaine, alkylaminopropionic acid, polydimethylsiloxane-polyether copolymer, and γ-aminopropyltrimethoxysilane, and any one of them can be selected when used.

[0013] Furthermore, in step 2, the stirring temperature of the inorganic lightweight insulation slurry is 4-25° C., the stirring speed is 100-3000 r / min, and the stirring time is 0.1 h-48 h.

[0014] Furthermore, the activator in step 3 includes sodium hydroxide, potassium hydroxide, potassium silicate, sodium silicate, potassium carbonate, sodium carbonate, calcium sulfate, phosphoric acid, sulfuric acid, and nitric acid, and any one of them can be selected when used.

[0015] Furthermore, the powder with excitation activity in step 3 includes metakaolin, volcanic ash, fly ash, slag (blast furnace granulated slag), silica fume, artificial silica-alumina gel, waste glass powder, rice husk ash, and synthetic powder. Any one or any combination can be selected when used.

[0016] Furthermore, in step 4, the stirring temperature of the high-temperature resistant, low thermal conductivity composite high-strength thermal insulation coating is 4-30° C., the stirring speed is 100-4000 r / min, and the stirring time is 1 min-3 h.

[0017] The present invention also provides a high-temperature resistant, low thermal conductivity composite high-strength thermal insulation coating prepared by the above preparation method, wherein the high-temperature resistant, low thermal conductivity composite high-strength thermal insulation coating has a compressive strength of 0-40 MPa, an adhesive strength of 0-5 MPa, and a bulk density of 0.2-2.7 g / cm 3 The thermal conductivity at room temperature is 0.03-0.2W / (m·K), and the thermal conductivity at high temperature (600℃) is 0.045-0.3W / (m·K).

[0018] The present invention also provides a method for using the high-temperature resistant, low-thermal conductivity composite high-strength thermal insulation coating, which mainly includes the following three methods: spraying, brushing, and roller coating. The spraying method is suitable for large-area steel structure base surfaces and thick coating requirements (design thickness ≥ 2mm). During operation, the spray gun needs to be kept vertical to the component surface (target distance 300mm) and the air pressure is controlled within the range of 0.5 to 0.8MPa; the brushing method adopts a criss-cross painting strategy for corners, complex and special-shaped parts and local repair scenes, and the thickness of a single coating is strictly controlled at 0.1-0.2mm to avoid sagging; the roller coating method is suitable for thin coating construction on flat walls (single coating thickness 0.3-0.5mm), and the coating consistency is achieved by ensuring the uniformity of the roller dipping and uniform rolling. The actual project needs to adapt the method according to the substrate morphology, coating thickness requirements and cost-effectiveness. Complex components should adopt a composite process of "spraying as the main + brushing as the supplement".

[0019] The present invention has the following beneficial effects:

[0020] (1) The coating of the present invention can still maintain an extremely low thermal conductivity (thermal conductivity <0.2W / (m·K)) in a high temperature environment (temperature>600°C). This effectively overcomes the defects of traditional organic thermal insulation materials that fail at high temperatures or the significant increase in thermal conductivity of inorganic materials at high temperatures, providing a long-lasting and efficient thermal insulation barrier for high-temperature equipment, pipelines, kilns, etc., significantly reducing heat loss and improving energy utilization efficiency.

[0021] (2) The coating of the present invention significantly improves its compressive strength (strength > 0.15 MPa) while maintaining ultra-low thermal conductivity. This high compressive resistance enables it to withstand large external loads and internal structural stresses, avoiding the problems of traditional aerogels and other materials that are prone to cracking and pulverizing during installation, use, or in pressurized environments. This greatly improves the durability and service life of the material, making it particularly suitable for working conditions that require resistance to certain pressures or vibrations.

[0022] (3) The coating of the present invention exhibits excellent bonding properties (bonding strength to substrates >1 MPa). This property enables the material to adhere firmly to various irregular surfaces or complex structures, simplifies the construction process (e.g., reduces or eliminates the need for additional adhesives and fasteners), effectively eliminates interfacial thermal bridges, ensures the integrity and long-term reliability of the thermal insulation layer, and prevents increased heat loss or safety hazards caused by bonding failure.

[0023] (4) The present invention successfully solves the contradiction between "low thermal conductivity" and "high strength / high toughness" and "good adhesion" of inorganic lightweight thermal insulation materials. Under extremely high temperature conditions, the material not only has excellent thermal insulation performance, but its mechanical integrity and interface bonding strength are also fully guaranteed, achieving a perfect unity of thermal insulation performance and structural / construction performance. High compressive strength prevents the material from collapsing and failing under pressure, and high bonding strength ensures that the material is tightly attached and not easy to fall off, which together ensures the long-term structural stability and operational safety of the thermal insulation layer of high-temperature equipment or pipelines, and reduces the risk of abnormal energy consumption, equipment overheating and even safety accidents caused by damage to the insulation layer.

[0024] (5) The coating of the present invention combines high-temperature resistance, ultra-low thermal conductivity, high compressive strength, and strong adhesion, making it widely applicable to harsh high-temperature environments where traditional insulation materials are difficult to meet, such as aerospace thermal protection, high-temperature industrial furnaces, petrochemical cracking units, nuclear power hot end components, special vehicle exhaust pipe insulation, and high-temperature sensor protection, thus possessing broad market prospects. Furthermore, by providing an efficient, long-life high-temperature insulation solution, the material of the present invention helps significantly reduce heat loss in industrial processes, lower fuel consumption, and greenhouse gas emissions, complying with national energy conservation and emission reduction policies and having important economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a physical diagram of the thermal conductivity test of the high-temperature resistant, low-thermal conductivity composite high-strength thermal insulation coating obtained in Examples 1-8 of the present invention at 600°C, wherein A, B, C, D, E, F, G, and H correspond to Example 1, Example 2, Example 3, Example 4, Example 5, Example 6, Example 7, and Example 8 respectively;

[0026] Figure 2 Actual pictures of the bonding strength test of the high-temperature resistant, low thermal conductivity composite high-strength thermal insulation coatings obtained in Examples 1-8 of the present invention, wherein A, B, C, D, E, F, G, and H correspond to Example 1, Example 2, Example 3, Example 4, Example 5, Example 6, Example 7, and Example 8, respectively;

[0027] Figure 3These are the compressive strength test results of the high-temperature resistant, low thermal conductivity composite high-strength thermal insulation coatings obtained in Examples 1-8 of the present invention after being treated at room temperature and 600°C for 2 hours.

[0028] Figure 4 These are the bonding strength test results of the high-temperature resistant, low thermal conductivity composite high-strength thermal insulation coatings obtained in Examples 1-8 of the present invention after being treated at room temperature and 600°C for 2 hours.

[0029] Figure 5 These are the thermal conductivity test results at room temperature and 600°C of the high-temperature resistant, low-thermal conductivity composite high-strength thermal insulation coatings obtained in Examples 1-8 of the present invention.

[0030] Figure 6 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments and drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] like Figure 6 The figure shows a process flow chart of a specific embodiment of the present invention. First, an inorganic lightweight thermal insulation material, fiber, surfactant and water are mixed, and stirred at a high concentration for a certain period of time at a specific temperature to obtain an inorganic lightweight thermal insulation slurry; a powder with excitation activity and an exciter are added to the inorganic lightweight thermal insulation slurry, and stirred at a high concentration for a certain period of time at a specific temperature to obtain a uniformly dispersed high-temperature resistant and low thermal conductivity composite high-strength thermal insulation coating. The present invention forms a geopolymer gel with a three-dimensional network structure during the curing process of the coating by adding an exciter and a powder with excitation activity, which significantly improves the mechanical strength and bonding strength of the material, so that it has excellent compressive and bonding properties while maintaining an extremely low thermal conductivity. This material has shown significant advantages and broad application prospects in the fields of metallurgy, chemical industry and petrochemical industry, nuclear energy, etc.

[0033] Example 1

[0034] (1) Weigh 245 g of expanded perlite, 490 g of water, 22.5 g of silicon carbide fiber, and 15 g of alkylbenzene sulfonate (ABS) surfactant and mix them evenly to obtain expanded perlite insulation slurry.

[0035] (2) stirring the slurry obtained in step (1) at 600 r / min at 20° C. for 6 h to obtain a uniformly dispersed expanded perlite insulation slurry;

[0036] (3) Weighing 23.7 g of metakaolin and 27.3 g of 1.0 M sodium silicate water glass, adding them to the evenly dispersed expanded perlite insulation slurry obtained in step (2) and mixing them evenly to obtain a mixed slurry;

[0037] (4) The mixed slurry obtained in step (3) is stirred at 2000 r / min at 30° C. for 10 min to obtain a uniformly dispersed high-temperature resistant, low thermal conductivity expanded perlite composite high-strength thermal insulation coating.

[0038] The thermal conductivity test of the high-temperature resistant and low-thermal conductivity expanded perlite composite high-strength thermal insulation coating obtained in Example 1 at 600°C is shown in the figure below: Figure 1 As shown in A.

[0039] The actual picture of the bonding strength test of the high-temperature resistant, low thermal conductivity expanded perlite composite high-strength thermal insulation coating obtained in Example 1 is as follows Figure 2 As shown in A.

[0040] The high-temperature resistant, low-thermal-conductivity expanded perlite composite high-strength thermal insulation coating obtained in Example 1 was subjected to compressive strength tests after being treated at room temperature and 600°C for 2h. Figure 3 The high-temperature resistant and low-thermal-conductivity expanded perlite composite high-strength thermal insulation coating obtained in Example 1 was subjected to bonding strength tests after being treated at room temperature and 600°C for 2h. Figure 4 The thermal conductivity of the high-temperature resistant and low-thermal-conductivity expanded perlite composite high-strength thermal insulation coating obtained in Example 1 was tested at room temperature and 600°C. Figure 5 As shown, they are 0.081W / (m·K) and 0.165W / (m·K) respectively. Good compressive strength can ensure that the insulation layer maintains its designed thickness and thermal insulation performance throughout the life cycle of the building, avoiding the decrease in thermal resistance due to compression. In composite insulation systems (such as sandwich panels, integrated insulation and decorative panels), the compressive strength of the insulation core material makes an important contribution to the mechanical properties of the entire board. Good bonding strength ensures that the insulation board can be firmly attached to the wall, roof or ground base (such as concrete, masonry, metal base plate, etc.), resisting the effects of self-weight, wind load (especially on exterior walls), thermal stress, water vapor penetration stress, etc., and preventing the insulation layer from peeling off from the base. This is the key to preventing safety hazards of falling objects from high altitudes.

[0041] Example 2

[0042] (1) Weigh 245 g of expanded perlite, 490 g of water, 22.5 g of silicon carbide fiber, and 15 g of hydroxyethyl cellulose surfactant and mix them evenly to obtain expanded perlite insulation slurry.

[0043] (2) stirring the slurry obtained in step (1) at 600 r / min at 20° C. for 6 h to obtain a uniformly dispersed expanded perlite insulation slurry;

[0044] (3) Weighing 23.7 g of metakaolin and 27.3 g of 1.0 M sodium silicate water glass, adding them to the expanded perlite insulation slurry uniformly dispersed in step (2) and mixing them evenly to obtain a mixed slurry;

[0045] (4) The mixed slurry obtained in step (3) is stirred at 2000 r / min at 30° C. for 10 min to obtain a uniformly dispersed high-temperature resistant, low thermal conductivity expanded perlite composite high-strength thermal insulation coating.

[0046] The thermal conductivity test of the high temperature resistant low thermal conductivity expanded perlite composite high strength thermal insulation coating obtained in Example 2 at 600°C is shown in the figure below: Figure 1 As shown in B.

[0047] The actual picture of the bonding strength test of the high-temperature resistant, low thermal conductivity expanded perlite composite high-strength thermal insulation coating obtained in Example 2 is as follows Figure 2 As shown in B.

[0048] The high-temperature resistant, low-thermal-conductivity expanded perlite composite high-strength thermal insulation coating obtained in Example 2 was subjected to compressive strength tests after being treated at room temperature and 600°C for 2h. Figure 3 The high-temperature resistant and low-thermal-conductivity expanded perlite composite high-strength thermal insulation coating obtained in Example 2 was subjected to bonding strength tests at room temperature and 600°C for 2h. Figure 4 The thermal conductivity of the high-temperature resistant and low-thermal-conductivity expanded perlite composite high-strength thermal insulation coating obtained in Example 2 was tested at room temperature and 600°C. Figure 5 As shown, the compressive strength, bonding strength, and thermal conductivity of the high-temperature resistant, low-thermal conductivity expanded perlite composite high-strength thermal insulation coating in Example 2, in which a hydroxyethyl cellulose surfactant is added, are significantly better than those in Example 1, indicating that the addition of different surfactants in this system significantly affects the performance of the material.

[0049] Example 3

[0050] (1) Weigh 245 g of hollow glass microspheres, 490 g of water, 22.5 g of silicon carbide fiber, and 15 g of hydroxyethyl cellulose surfactant and mix them evenly to obtain a hollow glass microsphere insulation slurry.

[0051] (2) stirring the slurry obtained in step (1) at 1000 r / min at 20° C. for 8 h to obtain a uniformly dispersed hollow glass microsphere insulation slurry;

[0052] (3) Weighing 23.7 g of metakaolin and 27.3 g of 1.0 M sodium silicate water glass, adding them to the hollow glass microsphere insulation slurry uniformly dispersed in step (2) and mixing them evenly to obtain a mixed slurry;

[0053] (4) The mixed slurry obtained in step (3) is stirred at 2000 r / min at 30° C. for 10 min to obtain a uniformly dispersed high-temperature resistant, low thermal conductivity hollow glass microsphere composite high-strength thermal insulation coating.

[0054] The thermal conductivity test of the high-temperature resistant and low-thermal-conductivity hollow glass microsphere composite high-strength thermal insulation coating obtained in Example 3 at 600°C is shown in the figure below: Figure 1 As shown in C.

[0055] The actual picture of the bonding strength test of the high-temperature resistant and low thermal conductivity hollow glass microspheres composite high-strength thermal insulation coating obtained in Example 3 is as follows Figure 2 As shown in C.

[0056] The high-temperature resistant and low-thermal-conductivity hollow glass microsphere composite high-strength thermal insulation coating obtained in Example 3 was subjected to compressive strength tests after being treated at room temperature and 600°C for 2h. Figure 3 The high-temperature resistant and low-thermal-conductivity hollow glass microsphere composite high-strength thermal insulation coating obtained in Example 3 was subjected to bonding strength tests after being treated at room temperature and 600°C for 2h. Figure 4 The high temperature resistant and low thermal conductivity hollow glass microsphere composite high strength thermal insulation coating obtained in Example 3 was tested for thermal conductivity at room temperature and 600°C. Figure 5 As shown, they are 0.061 W / (m·K) and 0.115 W / (m·K) respectively. Compared with Example 2, the hollow glass microsphere high-strength thermal insulation coating has a lower thermal conductivity than the expanded perlite high-strength thermal insulation coating, but its bonding strength and compressive strength are relatively poor.

[0057] Example 4

[0058] (1) Weigh 245 g of hollow glass microspheres, 490 g of water, 22.5 g of silicon carbide fiber, and 15 g of hydroxyethyl cellulose surfactant and mix them evenly to obtain a hollow glass microsphere insulation slurry.

[0059] (2) stirring the slurry obtained in step (1) at 1000 r / min at 20° C. for 8 h to obtain a uniformly dispersed hollow glass microsphere insulation slurry;

[0060] (3) Weighing 50 g of gypsum and adding it to the hollow glass microsphere insulation slurry uniformly dispersed in step (2) and mixing them evenly to obtain a mixed slurry;

[0061] (4) The mixed slurry obtained in step (3) was stirred at 2000 r / min for 10 min at 30° C. to obtain a uniformly dispersed gypsum-hollow glass microsphere thermal insulation coating.

[0062] The actual picture of the thermal conductivity test of the gypsum-hollow glass microsphere thermal insulation coating obtained in Example 4 at 600°C is as follows Figure 1 As shown in D.

[0063] The actual picture of the bonding strength test of the gypsum-hollow glass microsphere thermal insulation coating obtained in Example 4 is as follows Figure 2 As shown in D.

[0064] The compressive strength test of the gypsum-hollow glass microsphere thermal insulation coating obtained in Example 4 was carried out after treatment at room temperature and 600°C for 2h. Figure 3 The gypsum-hollow glass microsphere thermal insulation coating obtained in Example 4 was subjected to bonding strength tests after being treated at room temperature and 600°C for 2h. Figure 4 The thermal conductivity of the gypsum-hollow glass microsphere thermal insulation coating obtained in Example 4 was tested at room temperature and 600°C. Figure 5 Compared with Example 3, the compressive strength and flexural strength decreased to varying degrees, and the thermal conductivity increased significantly, indicating that the performance of gypsum as a reaction raw material is significantly inferior to that of geopolymer.

[0065] Example 5

[0066] (1) Weigh 245 g of fly ash beads, 490 g of water, 22.5 g of silicon carbide fiber, and 15 g of hydroxyethyl cellulose surfactant and mix them evenly to obtain a bead insulation slurry.

[0067] (2) stirring the slurry obtained in step (1) at 20° C. and 2000 r / min for 4 h to obtain a uniformly dispersed floating bead insulation slurry;

[0068] (3) Weighing 23.7 g of blast furnace granulated slag and 27.3 g of 1.8 M sodium silicate water glass, adding them to the evenly dispersed floating bead insulation slurry in step (2) and mixing them evenly to obtain a mixed slurry;

[0069] (4) The mixed slurry obtained in step (3) is stirred at 2000 r / min at 30° C. for 10 min to obtain a uniformly dispersed high-temperature resistant, low thermal conductivity floating bead composite high-strength thermal insulation coating.

[0070] The actual picture of the thermal conductivity test of the high temperature resistant low thermal conductivity floating beads composite high strength thermal insulation coating obtained in Example 5 at 600℃ is as follows Figure 1 As shown in E.

[0071] The actual picture of the bonding strength test of the high-temperature resistant and low thermal conductivity floating beads composite high-strength thermal insulation coating obtained in Example 5 is as follows Figure 2 As shown in E.

[0072] The high-temperature resistant and low-thermal conductivity floating beads composite high-strength thermal insulation coating obtained in Example 5 was subjected to compressive strength tests after being treated at room temperature and 600°C for 2h. Figure 3 The bonding strength test of the high temperature resistant and low thermal conductivity floating beads composite high strength thermal insulation coating obtained in Example 5 was carried out after treatment at room temperature and 600℃ for 2h. Figure 4 The thermal conductivity of the high-temperature resistant and low-thermal-conductivity floating beads composite high-strength thermal insulation coating obtained in Example 5 was tested at room temperature and 600°C. Figure 5 As shown, they are 0.07W / (m·K) and 0.155W / (m·K) respectively.

[0073] Example 6

[0074] (1) Weigh 245 g of fly ash beads, 490 g of water, 22.5 g of silicon carbide fiber, and 15 g of hydroxyethyl cellulose surfactant and mix them evenly to obtain a bead insulation slurry.

[0075] (2) stirring the slurry obtained in step (1) at 20° C. and 2000 r / min for 4 h to obtain a uniformly dispersed floating bead insulation slurry;

[0076] (3) Weighing 50 g of calcium sulfate and adding it to the evenly dispersed floating bead insulation slurry in step (2) and mixing them evenly to obtain a mixed slurry;

[0077] (4) The mixed slurry obtained in step (3) was stirred at 2000 r / min at 30° C. for 10 min to obtain a uniformly dispersed calcium sulfate-floating bead thermal insulation coating.

[0078] The actual picture of the thermal conductivity test of the calcium sulfate-floating bead thermal insulation coating obtained in Example 6 at 600°C is as follows Figure 1 As shown in F.

[0079] The actual picture of the bonding strength test of the calcium sulfate-floating bead thermal insulation coating obtained in Example 6 is as follows Figure 2 As shown in F.

[0080] The compressive strength test of the calcium sulfate-floating bead thermal insulation coating obtained in Example 6 was carried out after treatment at room temperature and 600°C for 2h. Figure 3 The calcium sulfate-bead thermal insulation coating obtained in Example 6 was treated at room temperature and 600℃ for 2h and then subjected to bonding strength tests. Figure 4 The thermal conductivity of the calcium sulfate-floating bead thermal insulation coating obtained in Example 6 was tested at room temperature and 600°C. Figure 5 Compared with Example 5, the compressive strength and flexural strength decreased, and the thermal conductivity increased, indicating that the performance of calcium sulfate as a reaction raw material is significantly inferior to that of geopolymer.

[0081] Example 7

[0082] (1) Weigh 187.5 g of aerogel, 490 g of water, 22.5 g of silicon carbide fiber, and 15 g of hydroxyethyl cellulose surfactant and mix them evenly to obtain an aerogel insulation slurry.

[0083] (2) stirring the slurry obtained in step (1) at 20° C. and 2000 r / min for 4 h to obtain a uniformly dispersed aerogel insulation slurry;

[0084] (3) Weighing 23.7 g of metakaolin and 27.3 g of 1.0 M sodium silicate water glass, adding them to the aerogel insulation slurry dispersed evenly in step (2) and mixing them evenly to obtain a mixed slurry;

[0085] (4) The mixed slurry obtained in step (3) is stirred at 2000 r / min at 30° C. for 10 min to obtain a uniformly dispersed high-temperature resistant, low thermal conductivity aerogel composite high-strength thermal insulation coating.

[0086] The actual picture of the thermal conductivity test of the high temperature resistant and low thermal conductivity aerogel composite high strength thermal insulation coating obtained in Example 7 at 600°C is as follows Figure 1 As shown in G.

[0087] The actual picture of the bonding strength test of the high-temperature resistant and low thermal conductivity aerogel composite high-strength thermal insulation coating obtained in Example 7 is as follows Figure 2 As shown in G.

[0088] The compressive strength test of the high-temperature resistant and low thermal conductivity aerogel composite high-strength thermal insulation coating obtained in Example 7 was carried out after treatment at room temperature and 600°C for 2h. Figure 3 The high-temperature resistant and low-thermal conductivity aerogel composite high-strength thermal insulation coating obtained in Example 7 was subjected to bonding strength tests at room temperature and 600°C for 2h. Figure 4The thermal conductivity of the high-temperature resistant and low-thermal-conductivity aerogel composite high-strength thermal insulation coating obtained in Example 7 was tested at room temperature and 600°C. Figure 5 As shown in FIG, , they are 0.035 W / (m·K) and 0.045 W / (m·K) respectively. Compared with Example 2, the compressive strength and thermal conductivity are significantly reduced, which is due to the low strength and low thermal conductivity of the aerogel.

[0089] Example 8

[0090] (1) Weigh 187.5 g of aerogel, 490 g of water, 22.5 g of silicon carbide fiber, and 15 g of hydroxyethyl cellulose surfactant and mix them evenly to obtain an aerogel insulation slurry.

[0091] (2) stirring the slurry obtained in step (1) at 20° C. and 2000 r / min for 4 h to obtain a uniformly dispersed aerogel insulation slurry;

[0092] (3) Weighing 50 g of cement and adding it to the aerogel insulation slurry uniformly dispersed in step (2) and mixing them evenly to obtain a mixed slurry;

[0093] (4) The mixed slurry obtained in step (3) was stirred at 2000 r / min at 30° C. for 10 min to obtain a uniformly dispersed cement-aerogel thermal insulation coating.

[0094] The actual picture of the thermal conductivity test of the cement-aerogel thermal insulation coating obtained in Example 8 at 600°C is as follows Figure 1 As shown in H.

[0095] The actual picture of the bonding strength test of the cement-aerogel thermal insulation coating obtained in Example 8 is as follows Figure 2 As shown in H.

[0096] The compressive strength of the cement-aerogel thermal insulation coating obtained in Example 8 was tested after treatment at room temperature and 600°C for 2h. Figure 3 The cement-aerogel thermal insulation coating obtained in Example 8 was subjected to bonding strength tests at room temperature and 600°C for 2h. Figure 4 The thermal conductivity of the cement-aerogel thermal insulation coating obtained in Example 8 was tested at room temperature and 600°C. Figure 5 As shown, they are 0.044 W / (m·K) and 0.059 W / (m·K), respectively. Compared with Example 7, although the aerogel thermal insulation coating with traditional cement as the binder also has a lower thermal conductivity, the mechanical properties of the cement-aerogel thermal insulation coating are poor, with extremely low compressive and bonding strengths.

[0097] In the above embodiments, the compressive strength test was carried out using the "Standard for Test Methods for Physical and Mechanical Properties of Concrete" (GB / T 50081-2019); the bonding strength test was carried out using the "Determination of Bond Strength of Adhesives·Metal and Plastic" (GB / T 39289-2020); and the thermal conductivity of the high-temperature resistant, low-thermal conductivity composite high-strength thermal insulation coating at room temperature and 600°C was measured using the "Determination of Steady-State Thermal Resistance and Related Properties of Insulating Materials·Heat Flow Meter Method" (GB / T 10295).

[0098] Although the present invention has been disclosed above with reference to preferred embodiments, this is not intended to limit the present invention. Any person skilled in the art may make some modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the definition of the claims.

Claims

1. A method for preparing a high-temperature resistant, low thermal conductivity composite high-strength thermal insulation coating, characterized in that: The steps include: (1) mixing an inorganic lightweight thermal insulation material, fiber, surfactant, and water to obtain an inorganic lightweight thermal insulation slurry; the weight ratio of the inorganic lightweight thermal insulation material, fiber, surfactant, and water is 100-200:1-50:0-30:200-500; (2) stirring the inorganic lightweight thermal insulation slurry of step (1) to obtain a uniformly dispersed inorganic lightweight thermal insulation slurry; (3) adding the powder with excitation activity and the exciter to the uniformly dispersed inorganic lightweight thermal insulation slurry obtained in step (2) to obtain a mixed slurry; the weight ratio of the powder with excitation activity, the exciter, and the inorganic lightweight thermal insulation slurry is 10-100:5-120:300-700; (4) Stirring the mixed slurry of step (3) to obtain a uniformly dispersed high-temperature resistant, low thermal conductivity composite high-strength thermal insulation coating.

2. The method for preparing a high-temperature resistant, low thermal conductivity composite high-strength thermal insulation coating according to claim 1, characterized in that: The inorganic lightweight insulation material described in step (1) includes rock wool, glass wool, aluminum silicate fiber wool, expanded perlite, vitrified microspheres, expanded vermiculite, diatomaceous earth, fly ash floating beads, hollow glass microspheres, aerogel, microporous calcium silicate, and nanoporous alumina.

3. The method for preparing a high-temperature resistant, low thermal conductivity composite high-strength thermal insulation coating according to claim 1, characterized in that: The fibers described in step (1) include silicon carbide fibers, alumina fibers, potassium titanate fibers, glass fibers, ceramic fibers, steel fibers, basalt fibers, hafnium carbide coated carbon fibers, zirconium oxide fibers, silicon nitride fibers, yttrium aluminum garnet fibers, and aluminum silicate fibers.

4. The method for preparing a high-temperature resistant, low thermal conductivity composite high-strength thermal insulation coating according to claim 1, characterized in that: The surfactant described in step (1) includes hydroxyethyl cellulose, polyether F127, polypropylene adipate, alkylphenol polyoxyethylene ether, fatty acid polyoxyethylene ester, alkylbenzene sulfonate, alkyl sulfonate, fatty alcohol phosphate salt, fatty alcohol polyoxyethylene ether sulfate, hexadecyltrimethylammonium bromide, carboxybetaine, sulfobetaine, alkylaminopropionic acid, polydimethylsiloxane-polyether copolymer, and γ-aminopropyltrimethoxysilane.

5. The method for preparing a high-temperature resistant, low thermal conductivity composite high-strength thermal insulation coating according to claim 1, characterized in that: In step (2), the stirring temperature of the inorganic lightweight thermal insulation slurry is 4-25° C., the stirring speed is 100-3000 r / min, and the stirring time is 0.1 h-48 h.

6. The method for preparing a high-temperature resistant, low thermal conductivity composite high-strength thermal insulation coating according to claim 1, characterized in that: The activator in step (3) includes sodium hydroxide, potassium hydroxide, potassium silicate, sodium silicate, potassium carbonate, sodium carbonate, calcium sulfate, phosphoric acid, sulfuric acid, and nitric acid.

7. The method for preparing a high-temperature resistant, low thermal conductivity composite high-strength thermal insulation coating according to claim 1, characterized in that: The powder with excitation activity in step (3) includes metakaolin, volcanic ash, fly ash, slag, silica fume, artificial silica-alumina gel, waste glass powder, rice husk ash, and synthetic powder.

8. The method for preparing a high-temperature resistant, low thermal conductivity composite high-strength thermal insulation coating according to claim 1, characterized in that: The stirring temperature of the mixed slurry in step (4) is 4-30° C., the stirring speed is 100-4000 r / min, and the stirring time is 1 min-3 h.

9. A high-temperature resistant, low thermal conductivity composite high-strength thermal insulation coating prepared by the preparation method according to any one of claims 1 to 8, characterized in that: The high-temperature resistant and low-thermal conductivity composite high-strength thermal insulation coating has a compressive strength of 0-40 MPa, an adhesive strength of 0-5 MPa, and a bulk density of 0.2-2.7 g / cm 3 The thermal conductivity at room temperature is 0.03-0.2W / (m·K), and the thermal conductivity at 600℃ is 0.045-0.3W / (m·K).

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