Preparation method of a porous calcium nanosilicate thermal insulation material

Abstract

The present invention relates to the technical field of nanomaterials, and specifically relates to a preparation method of a porous calcium silicate nanometer thermal insulation material. The preparation method includes: Preparation of a high-strength shell: The shell slurry is composed of tobermorite fiber, high-aluminum cement, quartz powder, modified diatomite, silicon dioxide, modified glass fiber, and a dispersant. The shell slurry is mixed and stirred evenly, poured into a mold, scraped evenly, and dried and demolded at 100-110 °C to obtain; The mixed slurry is poured into a mold and pressurized under the condition of 6-8 MPa to obtain a wet blank; The wet blanks are stacked and sent into a drying kiln at 250-260 °C for drying to obtain. The dispersant of the present invention enables the porous structures of the modified diatomite and the modified glass fiber to be intertwined with the micropores of the tobermorite fiber, forming a more complex three-dimensional pore network. This structure greatly increases the porosity of the material, reduces the thermal conductivity, and thus improves the thermal insulation performance.

Description

Technical Field

[0001] The present invention relates to the technical field of nanomaterials, and particularly to a preparation method of a porous nano calcium silicate thermal insulation material. Background Art

[0002] With the rapid development of the construction industry and the increasing emphasis on energy efficiency, thermal insulation materials, as an important part of building energy conservation, have continuously improved performance requirements. Porous nano calcium silicate thermal insulation materials have gradually become popular products in the market due to their excellent thermal insulation performance, good mechanical strength, and environmental protection characteristics.

[0003] The patent of invention with the publication number CN117585976A discloses a preparation method of a composite nano pore calcium silicate thermal insulation material, including: using tetraethyl orthosilicate, absolute ethanol, pure water, and hydrochloric acid solution to prepare silica aerogel; performing a composite treatment on the silica aerogel and tobermorite to prepare an aerogel composite tobermorite; performing supercritical drying on the aerogel composite tobermorite to obtain a nano pore calcium silicate material; preparing a nano calcium silicate slurry and a nano calcium carbonate slurry, and preparing a reinforced outer shell in a shell mold; using the prepared reinforced outer shell and the nano pore calcium silicate material to prepare a finished product of a composite nano pore calcium silicate thermal insulation material in a filter press mold. The present invention combines a thermal insulation material with a strength enhancing material to prepare a composite material, and applies this material in the preparation of the shell to obtain a composite material with excellent thermal insulation performance and structural strength.

[0004] Although there are various preparation methods for porous calcium silicate thermal insulation materials at present, most of them have problems such as insufficient thermal insulation performance, low mechanical strength, or complex preparation processes. For example, traditional calcium silicate thermal insulation materials often adopt a microporous structure, with limited thermal insulation effect and easy deformation due to temperature changes during use. In addition, although some preparation methods can prepare calcium silicate materials with a nano pore structure, they often have disadvantages such as high preparation cost and complex processes, making it difficult to be widely promoted and applied on a large scale. Based on this, the present invention proposes a preparation method of a porous nano calcium silicate thermal insulation material. Summary of the Invention

[0005] The purpose of the present invention is to provide a preparation method of a porous nano calcium silicate thermal insulation material, aiming to prepare a porous nano calcium silicate thermal insulation material with excellent thermal insulation performance.

[0006] The present invention provides a preparation method of a porous nano calcium silicate thermal insulation material, and the steps include:

[0007] (1)Preparation of high-strength shell: The shell slurry is composed of calcium hard silicate fiber, high-aluminum cement, quartz powder, modified diatomite, silica, modified glass fiber, and dispersant with a weight ratio of (20-30):(10-12):(20-24):(45-55):(10-16):(8-12):(4-6). Mix and stir the shell slurry evenly, pour it into a mold, scrape it evenly, and dry and demold it at 100-110 °C to obtain it.

[0008] (2)Preparation of thermal insulation material: Stir to obtain a mixed slurry of tobermorite nanosheets, silica aerogel, organic silicone adhesive, and calcium hard silicate fiber with a weight ratio of (10-12):(24-26):(2-3):(15-20); lay the high-strength shell in a filter press mold; pour the mixed slurry into the mold and press it under 6-8 MPa to obtain a wet blank; stack the wet blanks and send them to a drying kiln at 250-260 °C for drying to obtain it.

[0009] Further, the preparation method of the calcium hard silicate fiber includes: adding water and quartz powder according to a CaO / SiO2 molar ratio of 0.9-0.97:1 and a water-to-material ratio of 18-24:1, stirring and mixing evenly, then injecting it into a dynamic reaction kettle, and generating acicular or fibrous calcium hard silicate at 800-900 °C.

[0010] Further, the preparation method of the modified diatomite includes: impregnating the diatomite with a sulfuric acid solution first, washing it to neutrality and drying it for the first time, then impregnating it with a sodium hydroxide solution, washing it to neutrality and drying it for the second time, and then calcining the dried solid at 550-600 °C for 1-2 h and grinding it to obtain it.

[0011] Further, the mass concentration of the sulfuric acid solution is 10-12%, the temperature for impregnating with the sulfuric acid solution is 50-60 °C, and the impregnation time is 50-60 min.

[0012] Further, the mass concentration of the sodium hydroxide solution is 6-8%, the temperature for impregnating with the sodium hydroxide solution is 35-45 °C, and the impregnation time is 30-40 min.

[0013] Further, both the first washing and the second washing are performed with deionized water; the drying is vacuum drying, and the drying temperature is 60-70 °C.

[0014] Further, the preparation method of the modified glass fiber includes: mixing alumina, silane coupling agent KH550, ethanol, and deionized water, stirring for 2-3 h at 40-50 °C to obtain a dispersion liquid, then adding glass fiber, stirring at 200-300 r / min for 4-5 h, and drying at 50-60 °C after filtration to obtain it.

[0015] Further, the weight ratio of the alumina, silane coupling agent KH550, ethanol, deionized water, and glass fiber is (6 - 8):(0.4 - 0.5):(20 - 25):(15 - 20):(2 - 3).

[0016] Further, the dispersant is sodium dodecylbenzenesulfonate, polyvinyl alcohol, and deionized water with a weight ratio of (5 - 6):(8 - 10):(50 - 60).

[0017] Further, the preparation method of the tobermorite nanosheets includes: using silica, calcium oxide, and deionized water with a weight ratio of (1 - 2):(2 - 3):(6 - 8) as raw materials, ball - milling the mixed slurry, and then carrying out a hydrothermal reaction in a reaction kettle at a temperature of 220 - 240 °C to generate a tobermorite slurry, and putting it into a ball mill with ultrasonic equipment to be ultrasonically exfoliated into ultra - thin mesoporous nanosheets with a thickness of 1.23 nm.

[0018] The beneficial effects of the present invention are as follows:

[0019] In the present invention, the modified diatomite is treated alternately with sulfuric acid and sodium hydroxide, removing impurities and changing the surface properties, enhancing its performance as a filler. At the same time, the porous structure of the diatomite itself is retained or optimized during the modification process, further increasing the porosity of the material, which is beneficial to improving the thermal insulation effect. In addition, components such as modified diatomite and silica itself have a low thermal conductivity, and their distribution in the material further reduces the overall thermal conductivity, enhancing the thermal insulation performance.

[0020] In the present invention, the modified glass fiber is modified with alumina and silane coupling agent, improving its dispersibility and bonding force in the matrix. The addition of glass fiber not only enhances the mechanical properties of the material but also forms a three - dimensional network structure, which helps to fix and support the microporous structure of hard calcium silicate fiber and modified diatomite, preventing the material from collapsing or deforming during use. Moreover, the dispersibility and bonding property of the modified glass fiber with the matrix are improved, which helps to form a more uniform pore distribution inside the material.

[0021] In the present invention, the dispersant is a mixture of sodium dodecylbenzenesulfonate, polyvinyl alcohol, and deionized water, which can effectively improve the dispersibility of each component in water and prevent the occurrence of agglomeration. This helps to form a uniform mixture during the preparation process, ensuring the uniformity and stability of the internal structure of the material.

[0022] In addition, the dispersant enables the porous structures of the modified diatomaceous earth and the modified glass fiber to interweave with the micropores of the calcium hardsilicate fiber, forming a more complex three-dimensional pore network. This structure greatly increases the porosity of the material, reduces the thermal conductivity, and thus improves the heat insulation performance. Detailed implementation mode

[0023] The technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the scope of protection of the present invention. It should be noted that after the acid-base pretreatment of the modified diatomaceous earth, the diatomaceous earth is washed with deionized water until it is neutral. Silica aerogel: Type I, ≥90% below 3 microns, ≥45% below 1 micron, Guangzhou People's Chemical Factory. Organosilicon adhesive: Dow Corning SE 9184. Example 1

[0024] This example provides a preparation method of a porous nano-calcium silicate thermal insulation material. The steps include:

[0025] (1) Preparation of the high-strength shell: The shell slurry is composed of calcium hardsilicate fiber, high-aluminum cement, quartz powder, modified diatomaceous earth, silica, modified glass fiber, and dispersant with a weight ratio of 25:11:22:50:13:10:5. The shell slurry is mixed and stirred evenly, poured into a mold, scraped evenly, and dried and demolded at 105°C.

[0026] (2) Preparation of the thermal insulation material: Mix tobermorite nanosheets, silica aerogel, and organosilicon adhesive with a weight ratio of 11:25:2.5:17 with calcium hardsilicate fiber evenly to obtain a mixed slurry; lay the high-strength shell in a filter press mold; pour the mixed slurry into the mold and pressurize it at 6-8 MPa to obtain a wet blank; stack the wet blanks and send them into a drying kiln at 255°C for drying.

[0027] Among them, the preparation method of the calcium hardsilicate fiber includes: adding water and quartz powder according to a CaO / SiO2 molar ratio of 0.93:1 and a water-to-material ratio of 21:1, stirring and mixing evenly, and then injecting it into a dynamic reaction kettle to generate fibrous calcium hardsilicate at 850°C, that is, calcium hardsilicate fiber.

[0028] Among them, the preparation method of the modified diatomite includes: impregnating the diatomite with a sulfuric acid solution having a mass concentration of 11% for 55 min at an impregnation temperature of 55°C, washing it for the first time until neutral, drying it under vacuum at 65°C for 22 h, then impregnating it with a sodium hydroxide solution having a mass concentration of 7% for 35 min at an impregnation temperature of 40°C, washing it for the second time until neutral, drying it under vacuum at 65°C for 22 h, and then calcining the dried solid at 575°C for 1.5 h and grinding it to obtain the modified diatomite;

[0029] Among them, the preparation method of the modified glass fiber includes: mixing alumina, silane coupling agent KH550, ethanol and deionized water, stirring for 2.5 h at a temperature of 45°C to obtain a dispersion liquid, then adding glass fiber and stirring at 250 r / min for 4.5 h, and drying it at a temperature of 55°C after filtration to obtain the modified glass fiber; the weight ratio of alumina, silane coupling agent KH550, ethanol, deionized water and glass fiber is 7:0.45:22.5:17.5:2.5;

[0030] Among them, the dispersant is sodium dodecylbenzenesulfonate, polyvinyl alcohol and deionized water with a weight ratio of 5.5:9:55;

[0031] Among them, the preparation method of the tobermorite nanosheets includes: using silica, calcium oxide and deionized water with a weight ratio of 1.5:2.5:7 as raw materials, ball-milling the mixed slurry, and then carrying out a hydrothermal reaction in a reaction kettle at 230°C to generate a tobermorite slurry, putting it into a ball mill with an ultrasonic device, and using ultrasonic waves to peel it into ultra-thin mesoporous nanosheets with a thickness of 1.23 nm. Example 2

[0032] This example provides a preparation method of a porous nano calcium silicate thermal insulation material, and the steps include:

[0033] (1) Preparation of the high-strength shell: The shell slurry is composed of hard calcium silicate fiber, high-aluminum cement, quartz powder, modified diatomite, silica, modified glass fiber, and dispersant with a weight ratio of 20:10:20:45:10:8:4. Mix and stir the shell slurry evenly, pour it into a mold, scrape it evenly, and dry and demold it at 100°C to obtain the high-strength shell;

[0034] (2) Preparation of the thermal insulation material: Stir the tobermorite nanosheets, silica aerogel, organic silicone adhesive and hard calcium silicate fiber with a weight ratio of 10:24:2:15 evenly to obtain a mixed slurry; lay the high-strength shell in a filter press mold; pour the mixed slurry into the mold and pressurize it at 6 MPa to obtain a wet blank; stack the wet blanks and send them into a drying kiln at 250°C for drying to obtain the thermal insulation material.

[0035] Among them, the preparation method of the calcium hard silicate fiber includes: adding water and quartz powder according to a CaO / SiO2 molar ratio of 0.9 and a water-to-material ratio of 18:1, stirring and mixing evenly, then feeding into a dynamic reaction kettle, and generating fibrous calcium hard silicate, namely calcium hard silicate fiber, under the condition of 800 °C.

[0036] Among them, the preparation method of the modified diatomite includes: impregnating the diatomite with a sulfuric acid solution with a mass concentration of 10% for 50 min at an impregnation temperature of 50 °C, washing for the first time until neutral, drying under vacuum at 60 °C for 20 h, then impregnating with a sodium hydroxide solution with a mass concentration of 6% for 30 min at an impregnation temperature of 35 °C, washing for the second time until neutral, drying under vacuum at 60 °C for 20 h, and then calcining the dried solid at 550 °C for 1 h and grinding to obtain it;

[0037] Among them, the preparation method of the modified glass fiber includes: mixing alumina, silane coupling agent KH550, ethanol and deionized water, stirring for 2 h at a temperature of 40 °C to obtain a dispersion liquid, then adding glass fiber, stirring at 200 r / min for 4 h, filtering and drying at a temperature of 50 °C to obtain it; the weight part ratio of alumina, silane coupling agent KH550, ethanol, deionized water and glass fiber is 6:0.4:20:15:2;

[0038] Among them, the dispersant is sodium dodecyl benzene sulfonate, polyvinyl alcohol and deionized water with a weight part ratio of 5:8:50;

[0039] Among them, the preparation method of the tobermorite nanosheet includes: using silica, calcium oxide and deionized water with a weight part ratio of 1:2:6 as raw materials, ball-milling the mixed slurry, then carrying out hydrothermal reaction in a reaction kettle at a temperature of 220 °C to generate a tobermorite slurry, putting it into a ball mill with an ultrasonic device, and using ultrasonic waves to peel it into ultra-thin mesoporous nanosheets with a thickness of 1.23 nm. Example 3

[0040] This example provides a preparation method of a porous nano calcium silicate thermal insulation material, and the steps include:

[0041] (1) Preparation of the high-strength shell: The shell slurry is composed of calcium hard silicate fiber, high-aluminum cement, quartz powder, modified diatomite, silica, modified glass fiber, and dispersant with a weight part ratio of 30:12:24:55:16:12:6. Mix and stir the shell slurry evenly, pour it into a mold, scrape it evenly, and dry and demold it at 110 °C.

[0042] (2)Preparation of thermal insulation material: Stir toluite nanosheets, silica aerogel, organic silicone adhesive and calcium hard silicate fiber with a weight ratio of 12:26:3:20 evenly to obtain a mixed slurry; lay a high-strength shell in a filter press mold; pour the mixed slurry into the mold and pressurize it under 8 MPa to obtain a wet blank; stack the wet blanks and send them into a drying kiln at 260 °C for drying to obtain the product.

[0043] Among them, the preparation method of the calcium hard silicate fiber includes: adding water and quartz powder according to the molar ratio of CaO / SiO2 of 0.97:1 and the water-to-material ratio of 24:1, stirring and mixing evenly, then injecting into a dynamic reaction kettle, and generating fibrous calcium hard silicate at 900 °C, that is, calcium hard silicate fiber.

[0044] Among them, the preparation method of modified diatomite includes: impregnating diatomite with a sulfuric acid solution with a mass concentration of 12% for 60 min at an impregnation temperature of 60 °C, washing to neutral for the first time, drying under vacuum at 70 °C for 24 h, then impregnating with a sodium hydroxide solution with a mass concentration of 8% for 40 min at an impregnation temperature of 45 °C, washing to neutral for the second time, drying under vacuum at 70 °C for 24 h, then calcining the dried solid at 600 °C for 2 h, and grinding to obtain the product;

[0045] Among them, the preparation method of modified glass fiber includes: mixing alumina, silane coupling agent KH550, ethanol and deionized water, stirring for 3 h at a temperature of 50 °C to obtain a dispersion liquid, then adding glass fiber, stirring at 300 r / min for 5 h, filtering and drying at a temperature of 60 °C to obtain the product; the weight ratio of alumina, silane coupling agent KH550, ethanol, deionized water and glass fiber is 8:0.5:25:20:3;

[0046] Among them, the dispersant is sodium dodecyl benzene sulfonate, polyvinyl alcohol and deionized water with a weight ratio of 6:10:60;

[0047] Among them, the preparation method of the toluite nanosheets includes: using silica, calcium oxide and deionized water with a weight ratio of 2:3:8 as raw materials, ball-milling the mixed slurry, then carrying out hydrothermal reaction in a reaction kettle at a temperature of 240 °C to generate a toluite slurry, putting it into a ball mill with an ultrasonic device, and using ultrasonic waves to peel it into ultra-thin mesoporous nanosheets with a thickness of 1.23 nm. Example 4

[0048] This example provides a preparation method of a porous nano-calcium silicate thermal insulation material, and the steps include:

[0049] (1)Preparation of high-strength shell: The shell slurry is composed of calcium silicate fiber, high-aluminum cement, quartz powder, modified diatomite, silica, modified glass fiber, and dispersant with a weight ratio of 20:12:20:55:10:12:4. Mix and stir the shell slurry evenly, pour it into a mold, scrape it evenly, and dry and demold it at 110 °C to obtain it;

[0050] (2)Preparation of thermal insulation material: Stir to obtain a mixed slurry from tobermorite nanosheets, silica aerogel, organic silicone adhesive, and calcium silicate fiber with a weight ratio of 10:26:2:20; lay the high-strength shell in a filter press mold; pour the mixed slurry into the mold and press it under 6 MPa to obtain a wet blank; stack the wet blanks and send them to a drying kiln at 260 °C for drying to obtain it.

[0051] Among them, the preparation method of the calcium silicate fiber includes: adding water and quartz powder according to a CaO / SiO2 molar ratio of 0.9:1 and a water-to-material ratio of 24:1, stirring and mixing evenly, then injecting it into a dynamic reaction kettle, and generating fibrous calcium silicate at 800 °C, that is, calcium silicate fiber.

[0052] Among them, the preparation method of the modified diatomite includes: impregnating the diatomite with a sulfuric acid solution with a mass concentration of 10% for 60 min at an impregnation temperature of 50 °C, washing it to neutral for the first time, drying it under vacuum at 70 °C for 20 h, then impregnating it with a sodium hydroxide solution with a mass concentration of 8% for 30 min at an impregnation temperature of 45 °C, washing it to neutral for the second time, drying it under vacuum at 60 °C for 24 h, then calcining the dried solid at 550 °C for 2 h, and grinding it to obtain it;

[0053] Among them, the preparation method of the modified glass fiber includes: mixing alumina, silane coupling agent KH550, ethanol, and deionized water, stirring for 3 h at a temperature of 40 °C to obtain a dispersion liquid, then adding glass fiber, stirring at 200 r / min for 5 h, filtering, and drying at a temperature of 50 °C to obtain it; the weight ratio of alumina, silane coupling agent KH550, ethanol, deionized water, and glass fiber is 8:0.4:25:15:3;

[0054] Among them, the dispersant is sodium dodecylbenzenesulfonate, polyvinyl alcohol, and deionized water with a weight ratio of 5:10:50;

[0055] Among them, the preparation method of the tobermorite nanosheets includes: using silica, calcium oxide, and deionized water with a weight ratio of 1:3:6 as raw materials, ball-milling the mixed slurry, then carrying out hydrothermal reaction in a reaction kettle at a temperature of 220 °C to generate a tobermorite slurry, putting it into a ball mill with an ultrasonic device, and using ultrasonic waves to peel it into ultra-thin mesoporous nanosheets of 1.23 nm.

[0056] Comparative Example 1

[0057] This comparative example provides a method for preparing a porous calcium silicate nanometer thermal insulation material, and the steps include:

[0058] (1) Preparation of a high-strength shell: The shell slurry is composed of tobermorite fibers, high-aluminum cement, quartz powder, modified diatomaceous earth, silica, modified glass fibers, and a dispersant with a weight ratio of 25:11:22:50:13:10:5. The shell slurry is mixed and stirred evenly, poured into a mold, scraped evenly, and dried and demolded at 105 °C to obtain it;

[0059] (2) Preparation of the thermal insulation material: Mix tobermorite nanosheets, silica aerogel, organic silicone adhesive, and tobermorite fibers with a weight ratio of 11:25:2.5:17 evenly to obtain a mixed slurry; lay the high-strength shell in the filter press mold; pour the mixed slurry into the mold and pressurize it under 6 - 8 MPa to obtain a wet blank; stack the wet blanks and send them into a drying kiln at 255 °C for drying to obtain it.

[0060] Among them, the preparation method of the tobermorite fibers includes: adding water and quartz powder according to a CaO / SiO2 molar ratio of 0.93:1 and a water-to-material ratio of 21:1, stirring and mixing evenly, then injecting into a dynamic reaction kettle, and generating fibrous tobermorite at 850 °C, that is, tobermorite fibers.

[0061] Among them, the preparation method of the modified diatomaceous earth includes: impregnating diatomaceous earth with a sodium hydroxide solution with a mass concentration of 7% for 35 min at an impregnation temperature of 40 °C, washing to neutrality, drying at 65 °C under vacuum for 22 h, then calcining the dried solid at 575 °C for 1.5 h, and grinding to obtain it;

[0062] Among them, the preparation method of the modified glass fibers includes: mixing alumina, silane coupling agent KH550, ethanol, and deionized water, stirring for 2.5 h at 45 °C to obtain a dispersion liquid, then adding glass fibers, stirring at 250 r / min for 4.5 h, filtering, and drying at 55 °C to obtain it; the weight ratio of alumina, silane coupling agent KH550, ethanol, deionized water, and glass fibers is 7:0.45:22.5:17.5:2.5;

[0063] Among them, the dispersant is sodium dodecylbenzenesulfonate, polyvinyl alcohol, and deionized water with a weight ratio of 5.5:9:55;

[0064] Among them, the preparation method of the tobermorite nanosheets includes: using silica, calcium oxide, and deionized water with a weight ratio of 1.5:2.5:7 as raw materials, ball-milling the mixed slurry, and then carrying out a hydrothermal reaction in a reaction kettle at a temperature of 230 °C to generate a tobermorite slurry, which is put into a ball mill with ultrasonic equipment and exfoliated into ultra-thin mesoporous nanosheets with a thickness of 1.23 nm by using ultrasonic waves.

[0065] Comparative Example 2

[0066] This comparative example provides a preparation method of a porous calcium silicate nanowool thermal insulation material, and the steps include:

[0067] (1) Preparation of the high-strength shell: The shell slurry is composed of hard calcium silicate fiber, high-aluminum cement, quartz powder, modified diatomite, silica, modified glass fiber, and dispersant with a weight ratio of 25:11:22:50:13:10:5. The shell slurry is mixed and stirred evenly and poured into a mold, scraped evenly, and dried and demolded at 105 °C to obtain it;

[0068] (2) Preparation of the thermal insulation material: Stir the tobermorite nanosheets, silica aerogel, silicone adhesive, and hard calcium silicate fiber with a weight ratio of 11:25:2.5:17 evenly to obtain a mixed slurry; lay the high-strength shell in a filter press mold; pour the mixed slurry into the mold and pressurize it at 6 - 8 MPa to obtain a wet blank; stack the wet blanks and send them into a drying kiln at 255 °C for drying to obtain it.

[0069] Among them, the preparation method of the hard calcium silicate fiber includes: adding water and quartz powder according to a CaO / SiO2 molar ratio of 0.93:1 and a water-to-material ratio of 21:1, stirring and mixing evenly, then pumping it into a dynamic reaction kettle, and generating fibrous hard calcium silicate at 850 °C, that is, hard calcium silicate fiber.

[0070] Among them, the preparation method of the modified diatomite includes: impregnating diatomite with a sulfuric acid solution with a mass concentration of 11% for 55 min at an impregnation temperature of 55 °C, washing it to neutral for the first time, drying it under vacuum at 65 °C for 22 h, then calcining the dried solid at 575 °C for 1.5 h, and grinding it to obtain it;

[0071] Among them, the preparation method of the modified glass fiber includes: mixing alumina, silane coupling agent KH550, ethanol, and deionized water, stirring for 2.5 h at a temperature of 45 °C to obtain a dispersion liquid, then adding glass fiber, stirring at 250 r / min for 4.5 h, filtering, and drying at 55 °C to obtain it; the weight ratio of alumina, silane coupling agent KH550, ethanol, deionized water, and glass fiber is 7:0.45:22.5:17.5:2.5;

[0072] Among them, the dispersant is sodium dodecylbenzenesulfonate, polyvinyl alcohol and deionized water with a weight ratio of 5.5:9:55;

[0073] Among them, the preparation method of the tobermorite nanosheets includes: using silica, calcium oxide and deionized water with a weight ratio of 1.5:2.5:7 as raw materials, ball-milling the mixed slurry, and then carrying out hydrothermal reaction in a reaction kettle at a temperature of 230 °C to generate a tobermorite slurry, which is put into a ball mill with ultrasonic equipment and exfoliated into ultrathin mesoporous nanosheets of 1.23 nm by using ultrasonic waves.

[0074] Comparative Example 3

[0075] This comparative example provides a preparation method of a porous nano-calcium silicate thermal insulation material, and the steps include:

[0076] (1) Preparation of the high-strength shell: The shell slurry is composed of hard calcium silicate fiber, high-aluminum cement, quartz powder, diatomite, silica, modified glass fiber, and dispersant with a weight ratio of 25:11:22:50:13:10:5. The shell slurry is mixed and stirred evenly, poured into a mold, scraped evenly, and dried and demolded at 105 °C;

[0077] (2) Preparation of the thermal insulation material: Stir the tobermorite nanosheets, silica aerogel, organic silicone adhesive and hard calcium silicate fiber with a weight ratio of 11:25:2.5:17 evenly to obtain a mixed slurry; lay the high-strength shell in a filter press mold; pour the mixed slurry into the mold and pressurize it at 6 - 8 MPa to obtain a wet blank; stack the wet blanks and send them into a drying kiln at 255 °C for drying to obtain.

[0078] Among them, the preparation method of the hard calcium silicate fiber includes: adding water and quartz powder according to a CaO / SiO2 molar ratio of 0.93:1 and a water-to-material ratio of 21:1, stirring and mixing evenly, then pumping it into a dynamic reaction kettle, and generating fibrous hard calcium silicate at 850 °C, that is, hard calcium silicate fiber.

[0079] Among them, the preparation method of the modified glass fiber includes: mixing alumina, silane coupling agent KH550, ethanol and deionized water, stirring for 2.5 h at a temperature of 45 °C to obtain a dispersion liquid, then adding glass fiber, stirring at 250 r / min for 4.5 h, and drying at a temperature of 55 °C after filtration; the weight ratio of alumina, silane coupling agent KH550, ethanol, deionized water and glass fiber is 7:0.45:22.5:17.5:2.5;

[0080] Among them, the dispersant is sodium dodecylbenzenesulfonate, polyvinyl alcohol and deionized water with a weight ratio of 5.5:9:55;

[0081] Among them, the preparation method of the tobermorite nanosheets includes: using silica, calcium oxide, and deionized water with a weight ratio of 1.5:2.5:7 as raw materials, ball-milling the mixed slurry, and then carrying out hydrothermal reaction in a reaction kettle at a temperature of 230 °C to generate tobermorite slurry, which is put into a ball mill equipped with an ultrasonic device and ultrasonically peeled into ultra-thin mesoporous nanosheets with a thickness of 1.23 nm.

[0082] Comparative Example 4

[0083] This comparative example provides a preparation method of a porous calcium silicate nanosilicate thermal insulation material, and the steps include:

[0084] (1) Preparation of the high-strength shell: The shell slurry is composed of tobermorite fibers, high-aluminum cement, quartz powder, silica, modified glass fibers, and a dispersant with a weight ratio of 25:11:22:13:10:5. The shell slurry is mixed and stirred evenly, poured into a mold, scraped evenly, and dried and demolded at 105 °C to obtain it;

[0085] (2) Preparation of the thermal insulation material: Mix and stir evenly the tobermorite nanosheets, silica aerogel, organic silicone adhesive, and tobermorite fibers with a weight ratio of 11:25:2.5:17 to obtain a mixed slurry; lay the high-strength shell in a filter press mold; pour the mixed slurry into the mold and pressurize it at 6 - 8 MPa to obtain a wet blank; stack the wet blanks and send them into a drying kiln at 255 °C for drying to obtain it.

[0086] Among them, the preparation method of the tobermorite fibers includes: adding water and quartz powder according to a CaO / SiO2 molar ratio of 0.93:1 and a water-to-material ratio of 21:1, stirring and mixing evenly, then injecting it into a dynamic reaction kettle, and generating fibrous tobermorite at 850 °C, that is, tobermorite fibers.

[0087] Among them, the preparation method of the modified glass fibers includes: mixing alumina, silane coupling agent KH550, ethanol, and deionized water, stirring for 2.5 h at a temperature of 45 °C to obtain a dispersion liquid, then adding glass fibers, stirring at 250 r / min for 4.5 h, and drying at a temperature of 55 °C after filtration to obtain it; the weight ratio of alumina, silane coupling agent KH550, ethanol, deionized water, and glass fibers is 7:0.45:22.5:17.5:2.5;

[0088] Among them, the dispersant is sodium dodecylbenzenesulfonate, polyvinyl alcohol, and deionized water with a weight ratio of 5.5:9:55;

[0089] Among them, the preparation method of the tobermorite nanosheets includes: using silica, calcium oxide, and deionized water with a weight ratio of 1.5:2.5:7 as raw materials, ball-milling the mixed slurry, and then carrying out a hydrothermal reaction in a reaction kettle at a temperature of 230 °C to generate a tobermorite slurry, which is placed in a ball mill equipped with an ultrasonic device and ultrasonically peeled into ultra-thin mesoporous nanosheets with a thickness of 1.23 nm.

[0090] Comparative Example 5

[0091] This comparative example provides a preparation method for a porous calcium silicate nanowool insulation material, and the steps include:

[0092] (1) Preparation of the high-strength shell: The shell slurry is composed of tobermorite fiber, high-aluminum cement, quartz powder, modified diatomite, silica, glass fiber, and dispersant with a weight ratio of 25:11:22:50:13:10:5. The shell slurry is mixed and stirred evenly and poured into a mold, scraped evenly, and dried and demolded at 105 °C.

[0093] (2) Preparation of the insulation material: Mix the tobermorite nanosheets, silica aerogel, silicone adhesive, and tobermorite fiber with a weight ratio of 11:25:2.5:17 evenly to obtain a mixed slurry; lay the high-strength shell in a filter press mold; pour the mixed slurry into the mold and apply pressure at 6 - 8 MPa to obtain a wet blank; stack the wet blanks and send them to a drying kiln at 255 °C for drying.

[0094] Among them, the preparation method of the tobermorite fiber includes: adding water and quartz powder according to a CaO / SiO2 molar ratio of 0.93:1 and a water-to-material ratio of 21:1, stirring and mixing evenly, and then injecting into a dynamic reaction kettle to generate fibrous tobermorite at 850 °C, that is, tobermorite fiber.

[0095] Among them, the preparation method of the modified diatomite includes: impregnating the diatomite with a sulfuric acid solution with a mass concentration of 11% for 55 min at an impregnation temperature of 55 °C, washing to neutral for the first time, drying under vacuum at 65 °C for 22 h, then impregnating with a sodium hydroxide solution with a mass concentration of 7% for 35 min at an impregnation temperature of 40 °C, washing to neutral for the second time, drying under vacuum at 65 °C for 22 h, and then calcining the dried solid at 575 °C for 1.5 h and grinding.

[0096] Among them, the dispersant is sodium dodecylbenzenesulfonate, polyvinyl alcohol, and deionized water with a weight ratio of 5.5:9:55.

[0097] Among them, the preparation method of the tobermorite nanosheets includes: using silica, calcium oxide, and deionized water with a weight ratio of 1.5:2.5:7 as raw materials, ball-milling the mixed slurry, and then carrying out a hydrothermal reaction in a reaction kettle at a temperature of 230 °C to generate a tobermorite slurry, which is placed in a ball mill equipped with an ultrasonic device and ultrasonically peeled into ultra-thin mesoporous nanosheets with a thickness of 1.23 nm.

[0098] Comparative Example 6

[0099] This comparative example provides a preparation method for a porous calcium silicate nanowool thermal insulation material. The steps include:

[0100] (1) Preparation of the high-strength shell: The shell slurry is composed of tobermorite fiber, high-aluminum cement, quartz powder, modified diatomite, and silica dispersant with a weight ratio of 25:11:22:50:13:5. The shell slurry is mixed and stirred evenly, poured into a mold, scraped evenly, and dried and demolded at 105 °C.

[0101] (2) Preparation of the thermal insulation material: Mix the tobermorite nanosheets, silica aerogel, organic silicone adhesive, and tobermorite fiber with a weight ratio of 11:25:2.5:17 evenly to obtain a mixed slurry; lay the high-strength shell in a filter press mold; pour the mixed slurry into the mold and apply pressure at 6 - 8 MPa to obtain a wet blank; stack the wet blanks and send them to a drying kiln at 255 °C for drying.

[0102] Among them, the preparation method of the tobermorite fiber includes: adding water and quartz powder according to a CaO / SiO2 molar ratio of 0.93:1 and a water-to-material ratio of 21:1, stirring and mixing evenly, and then injecting into a dynamic reaction kettle to generate fibrous tobermorite at 850 °C, that is, tobermorite fiber.

[0103] Among them, the preparation method of the modified diatomite includes: impregnating the diatomite with a sulfuric acid solution with a mass concentration of 11% for 55 min at an impregnation temperature of 55 °C, washing to neutral for the first time, drying under vacuum at 65 °C for 22 h, then impregnating with a sodium hydroxide solution with a mass concentration of 7% for 35 min at an impregnation temperature of 40 °C, washing to neutral for the second time, drying under vacuum at 65 °C for 22 h, and then calcining the dried solid at 575 °C for 1.5 h and grinding.

[0104] Among them, the dispersant is sodium dodecylbenzenesulfonate, polyvinyl alcohol, and deionized water with a weight ratio of 5.5:9:55.

[0105] Among them, the preparation method of the tobermorite nanosheets includes: using silica, calcium oxide, and deionized water with a weight ratio of 1.5:2.5:7 as raw materials, ball-milling the mixed slurry, and then carrying out hydrothermal reaction in a reaction kettle at a temperature of 230 °C to generate a tobermorite slurry, which is put into a ball mill equipped with an ultrasonic device and ultrasonically peeled into ultra-thin mesoporous nanosheets with a thickness of 1.23 nm.

[0106] Comparative Example 7

[0107] This comparative example provides a preparation method of a porous calcium silicate nanowool insulation material, and the steps include:

[0108] (1) Preparation of the high-strength shell: The shell slurry is composed of tobermorite fibers, high-alumina cement, quartz powder, modified diatomaceous earth, silica, modified glass fibers, and a dispersant with a weight ratio of 25:11:22:50:13:10:5. The shell slurry is mixed and stirred evenly, poured into a mold, scraped evenly, and dried and demolded at 105 °C to obtain it;

[0109] (2) Preparation of the insulation material: Stir the tobermorite nanosheets, silica aerogel, silicone adhesive, and tobermorite fibers with a weight ratio of 11:25:2.5:17 evenly to obtain a mixed slurry; lay the high-strength shell in a filter press mold; pour the mixed slurry into the mold and apply pressure at 6 - 8 MPa to obtain a wet blank; stack the wet blanks and send them into a drying kiln at 255 °C for drying to obtain it.

[0110] Among them, the preparation method of the tobermorite fibers includes: adding water and quartz powder according to a CaO / SiO2 molar ratio of 0.93:1 and a water-to-material ratio of 21:1, stirring and mixing evenly, and then injecting into a dynamic reaction kettle to generate fibrous tobermorite at 850 °C, that is, tobermorite fibers.

[0111] Among them, the preparation method of the modified diatomaceous earth includes: first impregnating the diatomaceous earth with a sulfuric acid solution with a mass concentration of 11% for 55 min at an impregnation temperature of 55 °C, washing to neutral for the first time, drying at 65 °C under vacuum for 22 h, then impregnating with a sodium hydroxide solution with a mass concentration of 7% for 35 min at an impregnation temperature of 40 °C, washing to neutral for the second time, drying at 65 °C under vacuum for 22 h, and then calcining the dried solid at 575 °C for 1.5 h and grinding to obtain it;

[0112] Among them, the preparation method of the modified glass fiber includes: mixing alumina, silane coupling agent KH550, ethanol and deionized water, stirring for 2.5 h at a temperature of 45 °C to obtain a dispersion liquid, then adding glass fiber, stirring for 4.5 h under the condition of 250 r / min, and drying at a temperature of 55 °C after filtration to obtain; the weight ratio of alumina, silane coupling agent KH550, ethanol, deionized water and glass fiber is 7:0.45:22.5:17.5:2.5;

[0113] Among them, the dispersant is polyvinyl alcohol and deionized water with a weight ratio of 9:55;

[0114] Among them, the preparation method of the tobermorite nanosheets includes: using silica, calcium oxide and deionized water with a weight ratio of 1.5:2.5:7 as raw materials, ball-milling the mixed slurry, and then carrying out hydrothermal reaction in a reaction kettle at a temperature of 230 °C to generate a tobermorite slurry, and putting it into a ball mill with an ultrasonic device, and using ultrasonic waves to peel it into ultra-thin mesoporous nanosheets with a thickness of 1.23 nm.

[0115] The porous nano-calcium silicate thermal insulation materials prepared in Examples 1-4 and Comparative Examples 1-7 were tested, and the results are shown in Table 1 below.

[0116] Table 1: Performance Test

[0117]

[0118] Finally, it should be noted that the applicant declares that the present invention uses the above-mentioned examples to illustrate the products and detailed preparation methods of the present invention, but the present invention is not limited to the above products and detailed preparation methods, that is, it does not mean that the present invention must rely on the above products and detailed preparation methods to be implemented. Those skilled in the art should understand that any improvement of the present invention, the equivalent substitution of each raw material of the products of the present invention and the addition of auxiliary components, the selection of specific methods, etc., all fall within the protection scope and the disclosure scope of the present invention.

[0119] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple deformations can be made to the technical solutions of the present invention. These simple deformations all belong to the protection scope of the present invention.

[0120] In addition, it should be noted that, in the above specific embodiments, the various specific technical features described can be combined in any suitable manner without conflict. In order to avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0121] In addition, any combination can be made among various different embodiments of the present invention, as long as it does not violate the idea of the present invention, and it should equally be regarded as the content disclosed by the present invention.

Claims

1. A method for preparing a porous nano calcium silicate thermal insulation material, characterized in that: include: (1) Preparation of high-strength shell: The shell slurry is composed of hard calcium silicate fiber, high-alumina cement, quartz powder, modified diatomaceous earth, silicon dioxide, modified glass fiber, and dispersant in a weight ratio of (20-30): (10-12): (20-24): (45-55): (10-16): (8-12): (4-6); the shell slurry is mixed and stirred evenly and poured into a mold, scraped evenly, and dried at 100-110°C and demolded to obtain the shell; (2) Preparation of thermal insulation material: Tobermorite nanosheets, silica aerogel, organic silicone adhesive and hard calcium silicate fiber in a weight ratio of (10-12): (24-26): (2-3): (15-20) are mixed evenly to obtain a mixed slurry; a high-strength shell is laid in a filter press mold; the mixed slurry is poured into the mold and pressurized at 6-8 MPa to obtain a wet blank, which is stacked and sent to a drying kiln at 250-260° C. for drying to obtain a wet blank; The preparation method of modified diatomite includes: the diatomite is first impregnated with a sulfuric acid solution, washed to neutrality for the first time, and dried, then impregnated with a sodium hydroxide solution, washed to neutrality for the second time, and dried, and then calcined at 550-600°C for 1-2h, and then ground to obtain the modified diatomite; The preparation method of modified glass fiber comprises: mixing aluminum oxide, silane coupling agent KH550, ethanol and deionized water, stirring at 40-50°C for 2-3 hours to obtain a dispersion, then adding glass fiber, stirring at 200-300r / min for 4-5 hours, filtering and drying at 50-60°C to obtain the modified glass fiber; the weight ratio of aluminum oxide, silane coupling agent KH550, ethanol, deionized water and glass fiber is (6-8): (0.4-0.5): (20-25): (15-20): (2-3); The mass concentration of sulfuric acid solution is 10-12%, and the immersion temperature of sulfuric acid solution is 50-60℃ and the time is 50-60min; The mass concentration of the sodium hydroxide solution is 6-8%, and the immersion temperature of the sodium hydroxide solution is 35-45°C and the time is 30-40 minutes; The dispersant is sodium dodecylbenzene sulfonate, polyvinyl alcohol and deionized water in a weight ratio of (5-6): (8-10): (50-60).

2. The method for preparing a porous nano calcium silicate thermal insulation material according to claim 1, characterized in that: Deionized water is used for both the first and second washings; the drying is vacuum drying, the drying temperature is 60-70° C., and the drying time is 20-24 hours.

3. The method for preparing a porous nano calcium silicate thermal insulation material according to claim 1, characterized in that: The preparation method of the tobermorite nanosheets comprises: using silicon dioxide, calcium oxide and deionized water in a weight ratio of (1-2): (2-3): (6-8) as raw materials, ball-milling the mixed slurry, then performing a hydrothermal reaction in a reactor at a temperature of 220-240° C. to generate tobermorite slurry, placing the slurry in a ball mill equipped with an ultrasonic device, and using ultrasonic exfoliation to obtain ultrathin mesoporous nanosheets of 1.23 nm.

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