AU2019467669B2 - A composite thermal insulation material and its preparation method - Google Patents
A composite thermal insulation material and its preparation method Download PDFInfo
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- AU2019467669B2 AU2019467669B2 AU2019467669A AU2019467669A AU2019467669B2 AU 2019467669 B2 AU2019467669 B2 AU 2019467669B2 AU 2019467669 A AU2019467669 A AU 2019467669A AU 2019467669 A AU2019467669 A AU 2019467669A AU 2019467669 B2 AU2019467669 B2 AU 2019467669B2
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/40—Porous or lightweight materials
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2201/00—Mortars, concrete or artificial stone characterised by specific physical values
- C04B2201/50—Mortars, concrete or artificial stone characterised by specific physical values for the mechanical strength
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
Abstract
Provided is a composite thermal insulation material and a preparation method therefor. The composite thermal insulation material is a cement-based silicon dioxide aerogel-diatomite composite thermal insulation material, and comprising, by mass: 40 to 70 parts of silicon dioxide aerogel-diatomite material, 100 parts of cement, 0.4 to 1.2 parts of polypropylene fiber, 4.2 to 5.1 parts of a coupling agent, 0.56 to 1.2 parts of cellulose ether and 2.8 to 5.1 parts of redispersible latex powder. For the composite thermal insulation material, fly ash is taken as a raw material, and diatomite is taken as a strength supporting material; the silicon dioxide aerogel-diatomite material is obtained by means of steps such as high-temperature calcination, sol-gel treatment, negative-pressure adsorption, water bath modification, and normal-pressure drying; then the silicon dioxide aerogel-diatomite material, cement and a proper amount of additives are evenly dry-mixed; and water is added, and stirring is conducted to obtain the composite thermal insulation material. The preparation method is simple and low-cost, the application performance of the obtained composite heat preservation and insulation material is good, and the strength meets building use requirements.
Description
A Composite Thermal Insulation Material and Its Preparation Method
Technical Field
The present invention relates to a composite thermal insulation material and its preparation method, in particular to a cement-based silica aerogel-diatomite composite thermal insulation material and its preparation method. It belongs to the field of thermal insulation materials.
Background Technology
With the increasingly worsening of global warming, the sea level is rising year by year, so the energy conservation of buildings has become an inevitable issue in the development of the construction industry. The use of thermal insulation materials is an important way to achieve energy conservation in buildings. Silica aerogel, as the solid material with the lowest density, is a research hotspot in the field of thermal insulation. By its traditional preparation method, silica aerogel is prepared from organic solvents as raw materials through supercritical drying. Such a method features high investment cost, complicated parameter control, long production time and intermittent production, Moreover, it is not safe as flammable and toxic solvent vapor may be released during the production process. In recent years, methods of preparing silica aerogel with atmospheric drying and low cost have become new research hotspots, but the quality of silica aerogel prepared via atmospheric drying needs to be improved, because such silica aerogel is easy to crack and shrink and contains many by-products. Moreover, such preparation methods need to consume a large amount of solvent and spend a long time in completing the solvent replacement process.
Content of the Invention
Technical problem: In an attempt to overcome the shortcomings and problems of existing technologies, the present invention provides a composite thermal insulation material and its preparation method, specifically providing a cement-based silica aerogel-diatomite composite thermal insulation material and its preparation method. The preparation method features a simple process and low cost and is easy to industrialize, and also has a certain strength. It overcomes the shortcomings of traditional silica aerogel that is too high in cost but too low in strength to be widely used in the construction industry. The thermal insulation material can adjust the indoor temperature and can greatly reduce the thermal conductivity of cement-based materials, thus saving energy significantly.
Technical solution: The present invention provides a composite thermal insulation material, which is a cement-based silica aerogel-diatomite composite thermal insulation material. By mass fraction, the composite thermal insulation material includes the following components:
Silica aerogel-diatomite material 40-70 parts
Cement 100 parts
Polypropylene (PP) fiber 0.4~1.2 parts
Coupling agent 4.2-5.1 parts
Cellulose ether 0.56~1.2 parts
Redispersible emulsion powder 2.8-5.1 parts.
In some embodiments, in the said silica aerogel-diatomite material, silica aerogel without diatomite has a specific surface area of >400m 2 /g, and diatomite is ultrafine diatomite with a particle size of <300 mesh (48[tm).
In some embodiments, the length of the said PP fiber is 6mm-12mm, and the said coupling agent is a liquid silane coupling agent.
In some embodiments, the said cellulose ether is a solid powder of hydroxypropyl methylcellulose, with a viscosity of 100000-200000MPa-s and an 80-mesh (178m-aperture) sieve pass rate of >98%; the said redispersible emulsion powder is a solid powder, with a 38-mesh (400jm-aperture) sieve reject rate of <4%, and a solid content >99%.
In some embodiments, the said cement-based silica aerogel-diatomite composite thermal insulation material has a room temperature thermal conductivity of 0.13-0.27W/(m•K) and a compressive strength of 3-5MPa.
-0 The present invention provides a preparation method for the composite thermal insulation material mentioned. The method includes the following steps:
1) Mix fly ash with sodium carbonate and grind them, and then calcinate the mixture at high temperature to obtain a calcined mixture;
2) Hydrolyze the calcined mixture with a viable acid, then adjust its pH to 3 - 7, and leave it to stand still and age to form a silica gel;
3) Wash the silica gel with deionized water and then with ethanol several times in sequence, then add diatomite into washed silica gel according to the mass ratio of silica gel to diatomite at 1:1-1:5, then stir the mixture well and place it under vacuum condition to have negative pressure adsorption for 12h ~48h until the diatomite completely enters the gel, to obtain a composite material;
4) According to the volume ratio of 8:1:1-8:2:1, mix n-hexane, trimethylchlorosilane and ethanol to obtain a modification solution, and then immerse the composite material in the modification solution for modification, every 8 -24h to replace the modification solution until the composite material is suspended or floating in the modification solution, then take it out, wash with n-hexane to obtain the modified composite material;
5) Dry the modified composite material in stages: dry it at room temperature ~ 40°C for 12 - 24 hours, and then dry it at 100-130°C for 2-4 hours, and repeat such drying until constant weight, to obtain a silica aerogel-diatomite material;
6) Diatomite material, cement, polypropylene (PP) fiber, coupling agent, cellulose ether and redispersible emulsion powder are mixed under dry conditions according to the proportion specified above in relation to the composite thermal insulation material, and then water is added to the mixture and stirred evenly to obtain cement-based silica aerogel-diatomite composite insulation material.
In some embodiments, the mixing and grinding of fly ash and sodium carbonate mentioned in step 1) refer to mixing fly ash and sodium carbonate at a mass ratio of 1:0.8 - 1:1.5 and then grinding the mixture to below 200 mesh (74[tm).
In some embodiments, the particle size of the fly ash described in step 1) is < 200 mesh (74[m), and the high-temperature calcination treatment described in step 1) refers to the high temperature calcination treatment at 750-85 0 °Cfor 1.5-2h.
In some embodiments, the viable acid described in step 2) is sulfuric acid, hydrochloric acid, hydrofluoric acid, phosphoric acid, oxalic acid or nitric acid; the adjusting reagent used to adjust the pH to 3-7 described in step 2) is ammonia water, and the standing aging time described in step 2) is one to two days.
In some embodiments, the"then water is added to the mixture and stirred evenly" described in step 6), the mass of the added water is 1-2 times the mass of cement.
Beneficial effects: Compared with existing technologies, the present invention has the following advantages:
1. The cement-based silica aerogel-diatomite composite thermal insulation material provided by the present invention is prepared by making silica wet gel with fly ash and then embedding it in diatomite and finally drying the resulted mixture in stages. It overcomes the drawbacks that organic thermal insulation materials are easily flammable and inorganic thermal insulation materials have relatively high thermal conductivity, while also overcoming the shortcomings that silica aerogel has a complex preparation process, high raw material costs and a narrow application range.
2. The present invention uses silica aerogel as the thermal insulation material and diatomite as the support material of the silica aerogel. The cement-based silica aerogel-diatomite composite thermal insulation material prepared by introducing the thermal insulation material into the cement material has low thermal conductivity and good thermal insulation performance, and its thermal conductivity decreases with the increasing content of the thermal insulation material silica aerogel.
3. In terms of mechanical properties, the cement-based silica aerogel-diatomite composite thermal insulation material provided by the present invention makes up for the drawbacks of existing silica aerogel thermal insulation materials, which have good thermal insulation performance but low strength and high cost. The strength of the cement-based silica aerogel-diatomite composite thermal insulation material decreases with the increasing content of thermal insulation material, and its minimum value is 3MPa, which can meet the mechanical performance requirements of masonry mortar buildings and make up for the drawbacks of existing silica aerogel thermal insulation materials, which have good thermal insulation performance but too low strength.
4. The present invention prepares cement-based silica aerogel-diatomite composite thermal insulation material with a wide range of raw materials, and the preparation cost is low. It overcomes the high-cost defect in the existing technologies, and the preparation method has simple equipment, convenient operation, and is easy to industrialize.
Figure 1 shows the scanning electron microscope photographs of the surface morphology of the raw material diatomite as well as the silica aerogel-diatomite materials prepared in Embodiment cases 1-4, where a is diatomite; b, c, and d are the silica aerogel-diatomite materials prepared in Embodiment cases 1-3 in sequence; both e and f are silica aerogel-diatomite materials prepared in Embodiment case 4;
Figure 2 shows the nitrogen adsorption and desorption curves of the raw material diatomite as well as the silica aerogel-diatomite materials prepared in Embodiment cases 1-4;
Figure 3 shows the XRD test diagrams of the raw material diatomite, the silica aerogel prepared without diatomite as well as the silica aerogel-diatomite materials prepared in Embodiment cases 1, 2 and 4;
Figure 4 shows the FT-IR test diagrams of the raw material diatomite, the silica aerogel prepared without diatomite as well as the silica aerogel-diatomite materials prepared in Embodiment cases 1, 2 and 4;
Figure 5 shows the thermal conductivity analysis diagrams of the cement slurry test block and 1#-9# samples prepared in Embodiment cases 1-9, where a is the thermal conductivity analysis diagrams of the cement slurry test block and 1#-4# samples prepared in Embodiment cases 1-4; b is the thermal conductivity analysis diagrams of the cement slurry test block and 5#-9# samples prepared in Embodiment cases 5-9;
Figure 6 shows the compressive strength analysis diagrams of the cement slurry test block and 1#-9# samples prepared in Embodiment cases 1-9, where a is the compressive strength analysis diagrams of the cement slurry test block and 1#-4# samples prepared in Embodiment cases 1-4; b is the compressive strength analysis diagrams of the cement slurry test block and 5#-9# samples prepared in Embodiment cases 5-9;
Figure 7 shows the preparation flowchart of the cement-based silica aerogel-diatomite composite thermal insulation material.
Specific embodiment schemes
The following will further describe the present invention in combination with specific embodiment schemes.
Embodiment 1
A composite thermal insulation material (1#), which is a cement-based silica aerogel-diatomite composite thermal insulation material, includes the following components in terms of mass fraction:
Silica aerogel-diatomite material 40 parts
Cement 100 parts
Polypropylene (PP) fiber 0.56 parts
Coupling agent 4.2 parts
Cellulose ether 0.84 parts
Redispersible emulsion powder 2.8 parts.
Wherein: the said coupling agent is a liquid silane coupling agent, the said redispersible emulsion powder is a solid powder, the said PP fiber has a length of 6 mm - 12 mm, and the said cellulose ether is a solid powder of hydroxypropyl methyl cellulose with a viscosity of 100000 MPa •S.
A preparation method of the said composite thermal insulation material includes the following steps (as shown in Figure 7):
1) Mix fly ash and sodium carbonate according to the mass ratio of 1:1.5 and then grind the mixture to below 200 mesh, then calcinate the mixture at 850°C for 2h to obtain the calcined mixture;
2) Hydrolyze the calcined mixture with sulfuric acid, then adjust the pH of the resulted solution to 3 with 5mol/L aqueous ammonia solution, and then leave the solution to stand still and age for I d to form a silica gel;
3) Wash the silica gel with deionized water and ethanol several times in sequence, then add 20 mass parts of diatomite into 20 mass parts of silica gel, stir the mixture evenly and place it under vacuum conditions to have negative pressure adsorption for 12h until the diatomite completely enters the gel, to get the composite material;
4) According to the volume ratio of 8:2:1, mix n-hexane, trimethylchlorosilane and ethanol to obtain the modification solution, and then immerse the composite material in the modification solution for modification, every 24h to replace the modification solution until the composite material is suspended or floating in the modification solution, then take it out, wash with n-hexane to obtain the modified composite material;
5) Dry the modified composite material in stages, dry it at room temperature for 24 hours and then dry it at 100°C for 2 hours, and repeat such drying until constant weight to obtain the silica aerogel-diatomite material;
6) Dry and mix the silica aerogel-diatomite material, cement, PP fiber, the coupling agent, cellulose ether and redispersible emulsion powder according to a certain ratio, and then add water into the mixture (the mass of water added is 1.82 times the mass of cement) and stir it evenly, to obtain the said cement-based silica aerogel-diatomite composite thermal insulation material.
Embodiment 2
A composite thermal insulation material (2#), which is a cement-based silica aerogel-diatomite composite thermal insulation material, includes the following components in terms of mass fraction:
Silica aerogel-diatomite material 40 parts
Cement 100 parts
Polypropylene (PP) fiber 0.56 parts
Coupling agent 4.2 parts
Cellulose ether 0.84 parts
Redispersible emulsion powder 2.8 parts.
Wherein: the said coupling agent is a liquid silane coupling agent, the said redispersible emulsion powder is a solid powder, the said PP fiber has a length of 6 mm - 12 mm, and the said cellulose ether is a solid powder of hydroxypropyl methyl cellulose with a viscosity of 100000 MPa •S.
A preparation method of the said composite thermal insulation material includes the following steps (as shown in Figure 7):
1) Mix fly ash and sodium carbonate according to the mass ratio of 1:1.5 and then grind the mixture to below 200 mesh, then calcinate the mixture at 850°C for 2h to obtain the calcined mixture;
2) Hydrolyze the calcined mixture with sulfuric acid, then adjust the pH of the resulted solution to 3 with 5mol/L aqueous ammonia solution, and then leave the solution to stand still and age for I d to form a silica gel;
3) Wash the silica gel with deionized water and ethanol several times in sequence, then add 26.7 mass parts of diatomite into 13.3 mass parts of silica gel, stir the mixture evenly and place it under vacuum conditions to have negative pressure adsorption for 12h until the diatomite completely enters the gel, to get the composite material;
4) According to the volume ratio of 8:2:1, mix n-hexane, trimethylchlorosilane and ethanol to obtain the modification solution, and then immerse the composite material in the modification solution for modification, every 24h to replace the modification solution until the composite material is suspended or floating in the modification solution, then take it out, wash with n-hexane to obtain the modified composite material;
5) Dry the modified composite material in stages, dry it at room temperature for 24 hours, and dry it at 100°C for 2 hours, and repeat such drying until constant weight to obtain the silica aerogel--diatomite material;
6) Dry and mix the silica aerogel-diatomite material, cement, PP fiber, the coupling agent, cellulose ether and redispersible emulsion powder according to a certain ratio, and then add water into the mixture (the mass of water added is 1.82 times the mass of cement) and stir it evenly, to obtain the said cement-based silica aerogel-diatomite composite thermal insulation material.
Embodiment 3
A composite thermal insulation material (3#), which is a cement-based silica aerogel-diatomite composite thermal insulation material, includes the following components in terms of mass fraction:
Silica aerogel-diatomite material 40 parts
Cement 100 parts
Polypropylene (PP) fiber 0.56 parts
Coupling agent 4.2 parts
Cellulose ether 0.84 parts
Redispersible emulsion powder 2.8 parts.
Wherein: the said coupling agent is a liquid silane coupling agent, the said redispersible emulsion powder is a solid powder, the said PP fiber has a length of 6 mm - 12 mm, and the said cellulose ether is a solid powder of hydroxypropyl methylcellulose with a viscosity of 100000 MPa •S.
A preparation method of the said composite thermal insulation material includes the following steps (as shown in Figure 7):
1) Mix fly ash and sodium carbonate according to the mass ratio of 1:1.5 and then grind the mixture to below 200 mesh, then calcinate the mixture at 850°C for 2h to obtain the calcined mixture;
2) Hydrolyze the calcined mixture with sulfuric acid, then adjust the pH of the resulted solution to 3 with 5mol/L aqueous ammonia solution, and then leave the solution to stand still and age for l d to form a silica gel;
3) Wash the silica gel with deionized water and ethanol several times in sequence, then add 30 mass parts of diatomite into 10 mass parts of silica gel, stir the mixture evenly and place it under vacuum conditions to have negative pressure adsorption for 12h until the diatomite completely enters the gel, to get the composite material;
4) According to the volume ratio of 8:2:1, mix n-hexane, trimethylchlorosilane and ethanol to obtain the modification solution, and then immerse the composite material in the modification solution for modification, every 24h to replace the modification solution until the composite material is suspended or floating in the modification solution, then take it out, wash with n-hexane to obtain the modified composite material;
5) Dry the modified composite material in stages, dry it at room temperature for 24 hours and then dry it at 100°C for 2 hours, and repeat such drying until constant weight to obtain the silica aerogel-diatomite material;
6) Dry and mix the silica aerogel-diatomite material, cement, PP fiber, the coupling agent, cellulose ether and redispersible emulsion powder according to a certain ratio, and then add water into the mixture (the mass of water added is 1.82 times the mass of cement) and stir it evenly, so as to obtain the said cement-based silica aerogel-diatomite composite thermal insulation material.
Embodiment 4
A composite thermal insulation material (4#), which is a cement-based silica aerogel-diatomite composite thermal insulation material, includes the following components in terms of mass fraction:
Silica aerogel-diatomite material 40 parts
Cement 100 parts
Polypropylene (PP) fiber 0.56 parts
Coupling agent 4.2 parts
Cellulose ether 0.84 parts
Redispersible emulsion powder 2.8 parts.
Wherein: the said coupling agent is a liquid silane coupling agent, the said redispersible emulsion powder is a solid powder, the said PP fiber has a length of 6 mm - 12 mm, and the said cellulose ether is a solid powder of hydroxypropyl methyl cellulose with a viscosity of 100000 MPa •S.
A preparation method of the said composite thermal insulation material includes the following steps (as shown in Figure 7):
1) Mix fly ash and sodium carbonate according to the mass ratio of 1:1.5 and then grind the mixture to below 200 mesh, then calcinate the mixture at 850°C for 2h to obtain the calcined mixture;
2) Hydrolyze the calcined mixture with sulfuric acid, then adjust the pH of the resulted solution to 3 with 5mol/L aqueous ammonia solution, and then leave the solution to stand still and age for I d to form a silica gel;
3) Wash the silica gel with deionized water and ethanol several times in sequence, then add 32 mass parts of diatomite into 8 mass parts of silica gel, stir the mixture evenly and place it under vacuum conditions to have negative pressure adsorption for 12h until the diatomite completely enters the gel, so as to get the composite material;
4) According to the volume ratio of 8:2:1, mix n-hexane, trimethylchlorosilane and ethanol to obtain the modification solution, and then immerse the composite material in the modification solution for modification, every 24h to replace the modification solution until the composite material is suspended or floating in the modification solution, then take it out, wash with n-hexane to obtain the modified composite material;
5) Dry the modified composite material in stages, dry it at room temperature for 24 hours and then dry it at 100°C for 2 hours, and repeat such drying until constant weight to obtain the silica aerogel-diatomite material;
6) Dry and mix the silica aerogel-diatomite material, cement, PP fiber, the coupling agent, cellulose ether and redispersible emulsion powder according to a certain ratio, and then add water into the mixture (the mass of water added is 1.82 times the mass of cement) and stir it evenly, so as to obtain the said cement-based silica aerogel-diatomite composite thermal insulation material.
Embodiment 5
A composite thermal insulation material (5#), which is a cement-based silica aerogel-diatomite composite thermal insulation material, includes the following components in terms of mass fraction:
Silica aerogel-diatomite material 40 parts
Cement 100 parts
Polypropylene (PP) fiber 0.4 parts
Coupling agent 4.5 parts
Cellulose ether 0.9 parts
Redispersible emulsion powder 4 parts.
Wherein: the said coupling agent is a liquid silane coupling agent, the said redispersible emulsion powder is a solid powder, the said PP fiber has a length of 6 mm - 12 mm, and the said cellulose ether is a solid powder of hydroxypropyl methyl cellulose with a viscosity of 100000 MPa •S.
A preparation method of the said composite thermal insulation material includes the following steps (as shown in Figure 7):
1) Mix fly ash and sodium carbonate according to the mass ratio of 1:1.5 and then grind the mixture to below 200 mesh, then calcinate the mixture at 850 0C for 2h to obtain the calcined mixture;
2) Hydrolyze the calcined mixture with sulfuric acid, then adjust the pH of the resulted solution to 3 with 5mol/L aqueous ammonia solution, and then leave the solution to stand still and age for l d to form a silica gel;
3) Wash the silica gel with deionized water and ethanol several times in sequence, then add 27.7 mass parts of diatomite into 13.3 mass parts of silica gel, stir the mixture evenly and place it under vacuum conditions to have negative pressure adsorption for 12h until the diatomite completely enters the gel, so as to get the composite material;
4) According to the volume ratio of 8:2:1, mix n-hexane, trimethylchlorosilane and ethanol to obtain the modification solution, and then immerse the composite material in the modification solution for modification, every 24h to replace the modification solution until the composite material is suspended or floating in the modification solution, then take it out, wash with n-hexane to obtain the modified composite material;
5) Dry the modified composite material in stages, dry it at room temperature for 24 hours and then dry it at 100°C for 2 hours, and repeat such drying until constant weight to obtain the silica aerogel-diatomite material;
6) Dry and mix the silica aerogel-diatomite material, cement, PP fiber, the coupling agent, cellulose ether and redispersible emulsion powder according to a certain ratio, and then add water into the mixture (the mass of water added is 1.3 times the mass of cement) and stir it evenly, so as to obtain the said cement-based silica aerogel-diatomite composite thermal insulation material.
Embodiment 6
A composite thermal insulation material (6#), which is a cement-based silica aerogel-diatomite composite thermal insulation material, includes the following components in terms of mass fraction:
Silica aerogel-diatomite material 50 parts
Cement 100 parts
Polypropylene (PP) fiber 0.5 parts
Coupling agent 4.65 parts
Cellulose ether 1 parts
Redispersible emulsion powder 3.1 parts.
Wherein: the said coupling agent is a liquid silane coupling agent, the said redispersible emulsion powder is a solid powder, the said PP fiber has a length of 6 mm - 12 mm, and the said cellulose ether is a solid powder of hydroxypropyl methyl cellulose with a viscosity of 100000 MPa •S.
A preparation method of the said composite thermal insulation material includes the following steps (as shown in Figure 7):
1) Mix fly ash and sodium carbonate according to the mass ratio of 1:1.5 and then grind the mixture to below 200 mesh, then calcinate the mixture at 850°C for 2h to obtain the calcined mixture;
2) Hydrolyze the calcined mixture with sulfuric acid, then adjust the pH of the resulted solution to 3 with 5mol/L aqueous ammonia solution, and then leave the solution to stand still and age for I d to form a silica gel;
3) Wash the silica gel with deionized water and ethanol several times in sequence, then add 33.3 mass parts of diatomite into 16.7 mass parts of silica gel, stir the mixture evenly and place it under vacuum conditions to have negative pressure adsorption for 12h until the diatomite completely enters the gel, to get the composite material;
4) According to the volume ratio of 8:2:1, mix n-hexane, trimethylchlorosilane and ethanol to obtain the modification solution, and then immerse the composite material in the modification solution for modification, every 24h to replace the modification solution until the composite material is suspended or floating in the modification solution, then take it out, wash with n-hexane to obtain the modified composite material;
5) Dry the modified composite material in stages, dry it at room temperature for 24 hours and then dry it at 100°C for 2 hours, and repeat such drying until constant weight to obtain the silica aerogel-diatomite material;
6) Dry and mix the silica aerogel-diatomite material, cement, PP fiber, the coupling agent, cellulose ether and redispersible emulsion powder according to a certain ratio, and then add water into the mixture (the mass of water added is 1.3 times the mass of cement) and stir it evenly, to obtain the said cement-based silica aerogel-diatomite composite thermal insulation material.
Embodiment 7
A composite thermal insulation material (7#), which is a cement-based silica aerogel-diatomite composite thermal insulation material, includes the following components in terms of mass fraction:
Silica aerogel-diatomite material 60 parts
Cement 100 parts
Polypropylene (PP) fiber 0.6 parts
Coupling agent 4.8 parts
Cellulose ether 1.1 parts
Redispersible emulsion powder 3.2 parts.
Wherein: the said coupling agent is a liquid silane coupling agent, the said redispersible emulsion powder is a solid powder, the said PP fiber has a length of 6 mm - 12 mm, and the said cellulose ether is a solid powder of hydroxypropyl methyl cellulose with a viscosity of 100000 MPa •S.
A preparation method of the said composite thermal insulation material includes the following steps (as shown in Figure 7):
1) Mix fly ash and sodium carbonate according to the mass ratio of 1:1.5 and then grind the mixture to below 200 mesh, then calcinate the mixture at 850°C for 2h to obtain the calcined mixture;
2) Hydrolyze the calcined mixture with sulfuric acid, then adjust the pH of the resulted solution to 3 with 5mol/L aqueous ammonia solution, and then leave the solution to stand still and age for l d to form a silica gel;
3) Wash the silica gel with deionized water and ethanol several times in sequence, then add 40 mass parts of diatomite into 20 mass parts of silica gel, stir the mixture evenly and place it under vacuum conditions to have negative pressure adsorption for 12h until the diatomite completely enters the gel, to get the composite material;
4) According to the volume ratio of 8:2:1, mix n-hexane, trimethylchlorosilane and ethanol to obtain the modification solution, and then immerse the composite material in the modification solution for modification, every 24h to replace the modification solution until the composite material is suspended or floating in the modification solution, then take it out, wash with n-hexane to obtain the modified composite material;
5) Dry the modified composite material in stages, dry it at room temperature for 24 hours and then dry it at 100°C for 2 hours, and repeat such drying until constant weight to obtain the silica aerogel-diatomite material;
6) Dry and mix the silica aerogel-diatomite material, cement, PP fiber, the coupling agent, cellulose ether and redispersible emulsion powder according to a certain ratio, and then add water into the mixture (the mass of water added is 1.3 times the mass of cement) and stir it evenly, to obtain the said cement-based silica aerogel-diatomite composite thermal insulation material.
Embodiment 8
A composite thermal insulation material (8#), which is a cement-based silica aerogel-diatomite composite thermal insulation material, includes the following components in terms of mass fraction:
Silica aerogel-diatomite material 70 parts
Cement 100 parts
Polypropylene (PP) fiber 0.7 parts
Coupling agent 4.95 parts
Cellulose ether 1.2 parts
Redispersible emulsion powder 3.3 parts.
Wherein: the said coupling agent is a liquid silane coupling agent, the said redispersible emulsion powder is a solid powder, the said PP fiber has a length of 6 mm - 12 mm, and the said cellulose ether is a solid powder of hydroxypropyl methyl cellulose with a viscosity of 100000 MPa •S.
A preparation method of the said composite thermal insulation material includes the following steps (as shown in Figure 7):
1) Mix fly ash and sodium carbonate according to the mass ratio of 1:1.5 and then grind the mixture to below 200 mesh, then calcinate the mixture at 850°C for 2h to obtain the calcined mixture;
2) Hydrolyze the calcined mixture with sulfuric acid, then adjust the pH of the resulted solution to 3 with 5mol/L aqueous ammonia solution, and then leave the solution to stand still and age for I d to form a silica gel;
3) Wash the silica gel with deionized water and ethanol several times in sequence, then add 47.7 mass parts of diatomite into 23.3 mass parts of silica gel, stir the mixture evenly and place it under vacuum conditions to have negative pressure adsorption for 12h until the diatomite completely enters the gel, to get the composite material;
4) According to the volume ratio of 8:2:1, mix n-hexane, trimethylchlorosilane and ethanol to obtain the modification solution, and then immerse the composite material in the modification solution for modification, every 24h to replace the modification solution until the composite material is suspended or floating in the modification solution, then take it out, wash with n-hexane to obtain the modified composite material;
5) Dry the modified composite material in stages, dry it at room temperature for 24 hours and then dry it at 100°C for 2 hours, and repeat such drying until constant weight to obtain the silica aerogel-diatomite material;
6) Dry and mix the silica aerogel-diatomite material, cement, PP fiber, the coupling agent, cellulose ether and redispersible emulsion powder according to a certain ratio, and then add water into the mixture (the mass of water added is 1.3 times the mass of cement) and stir it evenly, to obtain the said cement-based silica aerogel-diatomite composite thermal insulation material.
Embodiment 9
A composite thermal insulation material (9#), which is a cement-based silica aerogel-diatomite composite thermal insulation material, includes the following components in terms of mass fraction:
Silica aerogel-diatomite material 40 parts
Cement 100 parts
Polypropylene (PP) fiber 0.5 parts
Coupling agent 5.1 parts
Cellulose ether 1.02 parts
Redispersible emulsion powder 3.4 parts.
Wherein: the said coupling agent is a liquid silane coupling agent, the said redispersible emulsion powder is a solid powder, the said PP fiber has a length of 6 mm - 12 mm, and the said cellulose ether is a solid powder of hydroxypropyl methyl cellulose with a viscosity of 100000 MPa •S.
A preparation method of the said composite thermal insulation material includes the following steps (as shown in Figure 7):
1) Mix fly ash and sodium carbonate according to the mass ratio of 1:1.5 and then grind the mixture to below 200 mesh, then calcinate the mixture at 850 0C for 2h to obtain the calcined mixture;
2) Hydrolyze the calcined mixture with sulfuric acid, then adjust the pH of the resulted solution to 3 with 5mol/L aqueous ammonia solution, and then leave the solution to stand still and age for l d to form a silica gel;
3) Wash the silica gel with deionized water and ethanol several times in sequence, then add 27.7 mass parts of diatomite into 13.3 mass parts of silica gel, stir the mixture evenly and place it under vacuum conditions to have negative pressure adsorption for 12h until the diatomite completely enters the gel, to get the composite material;
4) According to the volume ratio of 8:2:1, mix n-hexane, trimethylchlorosilane and ethanol to obtain the modification solution, and then immerse the composite material in the modification solution for modification, every 24h to replace the modification solution until the composite material is suspended or floating in the modification solution, then take it out, wash with n-hexane to obtain the modified composite material;
5) Dry the modified composite material in stages, dry it at room temperature for 24 hours and then dry it at 100°C for 2 hours, and repeat such drying until constant weight to obtain the silica aerogel-diatomite material;
6) Dry and mix the silica aerogel-diatomite material, cement, PP fiber, the coupling agent, cellulose ether and redispersible emulsion powder according to a certain ratio, and then add water into the mixture (the mass of water added is 1.4 times the mass of cement) and stir it evenly, to obtain the said cement-based silica aerogel-diatomite composite thermal insulation material.
Embodiment 10
A composite thermal insulation material (10#), which is a cement-based silica aerogel-diatomite composite thermal insulation material, includes the following components in terms of mass fraction:
Silica aerogel-diatomite material 60 parts
Cement 100 parts
Polypropylene (PP) fiber 1.2 parts
Coupling agent 5.1 parts
Cellulose ether 0.56 parts
Redispersible emulsion powder 5.1 parts.
Wherein: the said coupling agent is a liquid silane coupling agent, the said redispersible emulsion powder is a solid powder, the said PP fiber has a length of 6 mm - 12 mm, and the said cellulose ether is a solid powder of hydroxypropyl methyl cellulose with a viscosity of 100000 MPa •S.
A preparation method of the said composite thermal insulation material includes the following steps (as shown in Figure 7):
1) Mix fly ash and sodium carbonate according to the mass ratio of 1:0.8 and then grind the mixture to below 200 mesh, then calcinate the mixture at 800°Cfor 2h to obtain the calcined mixture;
2) Hydrolyze the calcined mixture with phosphoric acid, then adjust the pH of the resulted solution to 5 with 5mol/L aqueous ammonia solution, and then leave the solution to stand still and age for l d to form a silica gel;
3) Wash the silica gel with deionized water and ethanol several times in sequence, then add 40 mass parts of diatomite into 20 mass parts of silica gel, stir the mixture evenly and place it under vacuum conditions to have negative pressure adsorption for 12h until the diatomite completely enters the gel, to get the composite material;
4) According to the volume ratio of 8:1:1, mix n-hexane, trimethylchlorosilane and ethanol to obtain the modification solution, and then immerse the composite material in the modification solution for modification, every 24h to replace the modification solution until the composite material is suspended or floating in the modification solution, then take it out, wash with n-hexane to obtain the modified composite material;
5) Dry the modified composite material in stages, dry it at 40°C for 24 hours and 120°C for 2 hours, and repeat the drying until constant weight to obtain the silica aerogel-diatomite material;
6) Dry and mix the silica aerogel-diatomite material, cement, PP fiber, the coupling agent, cellulose ether and redispersible emulsion powder according to a certain ratio, and then add water into the mixture (the mass of water added is 2 times the mass of cement) and stir it evenly, to obtain the said cement-based silica aerogel-diatomite composite thermal insulation material.
Embodiment 11
A composite thermal insulation material (11#), which is a cement-based silica aerogel-diatomite composite thermal insulation material, includes the following components in terms of mass fraction:
Silica aerogel-diatomite material 30 parts
Cement 100 parts
Polypropylene (PP) fiber 1.2 parts
Coupling agent 4.2 parts
Cellulose ether 0.56 parts
Redispersible emulsion powder 5.1 parts.
Wherein: the said coupling agent is a liquid silane coupling agent, the said redispersible emulsion powder is a solid powder, the said PP fiber has a length of 6 mm - 12 mm, and the said cellulose ether is a solid powder of hydroxypropyl methyl cellulose with a viscosity of 100000 MPa •S.
A preparation method of the said composite thermal insulation material includes the following steps (as shown in Figure 7):
1) Mix fly ash and sodium carbonate according to the mass ratio of 1:1 and then grind the mixture to below 200 mesh, then calcinate the mixture at 750°Cfor 2h to obtain the calcined mixture;
2) Hydrolyze the calcined mixture with nitric acid, then adjust the pH of the resulted solution to 7 with 5mol/L aqueous ammonia solution, and then leave the solution to stand still and age for I d to form a silica gel;
3) Wash the silica gel with deionized water and ethanol several times in sequence, then add 20 mass parts of diatomite into 10 mass parts of silica gel, stir the mixture evenly and place it under vacuum conditions to have negative pressure adsorption for 24h until the diatomite completely enters the gel, to get the composite material;
4) According to the volume ratio of 8:1:1, mix n-hexane, trimethylchlorosilane and ethanol to obtain the modification solution, and then immerse the composite material in the modification solution for modification, every 12h to replace the modification solution until the composite material is suspended or floating in the modification solution, then take it out, wash with n-hexane to obtain the modified composite material;
5) Dry the modified composite material in stages, dry it at 40°C for 12 hours and 130°C for 2 hours, and repeat the drying until constant weight to obtain the silica aerogel-diatomite material;
6) Dry and mix the silica aerogel-diatomite material, cement, PP fiber, the coupling agent, cellulose ether and redispersible emulsion powder according to a certain ratio, and then add water into the mixture (the mass of water added is 1.5 times the mass of cement) and stir it evenly, to obtain the said cement-based silica aerogel-diatomite composite thermal insulation material.
Embodiment 12
A composite thermal insulation material (12#), which is a cement-based silica aerogel-diatomite composite thermal insulation material, includes the following components in terms of mass fraction:
Silica aerogel-diatomite material 60 parts
Cement 100 parts
Polypropylene (PP) fiber 0.8 parts
Coupling agent 4.5 parts
Cellulose ether 0.9 parts
Redispersible emulsion powder 3.5 parts.
Wherein: the said coupling agent is a liquid silane coupling agent, the said redispersible emulsion powder is a solid powder, the said PP fiber has a length of 6 mm - 12 mm, and the said cellulose ether is a solid powder of hydroxypropyl methylcellulose with a viscosity of 200000 MPa •S.
A preparation method of the said composite thermal insulation material includes the following steps (as shown in Figure 7):
.0 1) Mix fly ash and sodium carbonate according to the mass ratio of 1:1.2 and then grind the mixture to below 200 mesh, then calcinate the mixture at 830°Cfor 1.8h to obtain the calcined mixture;
2) Hydrolyze the calcined mixture with hydrochloric acid, then adjust the pH of the resulted solution to 4 with 5mol/L aqueous ammonia solution, and then leave the solution to stand still and age for 1.5d to form a silica gel;
3) Wash the silica gel with deionized water and ethanol several times in sequence, then add 50 mass parts of diatomite into 10 mass parts of silica gel, stir the mixture evenly and place it under vacuum conditions to have negative pressure adsorption for 20h until the diatomite completely enters the gel, to get the composite material;
4) According to the volume ratio of 8:1.5:1, mix n-hexane, trimethylchlorosilane and ethanol to obtain the modification solution, and then immerse the composite material in the modification solution for modification, every 8h to replace the modification solution until the composite material is suspended or floating in the modification solution, then take it out, wash with n-hexane to obtain the modified composite material;
5) Dry the modified composite material in stages, dry it at 40°C for 16 hours and 110°C for 3 hours, and repeat the drying until constant weight to obtain the silica aerogel-diatomite material;
6) Dry and mix the silica aerogel-diatomite material, cement, PP fiber, the coupling agent, cellulose ether and redispersible emulsion powder according to a certain ratio, and then add water into the mixture (the mass of water added is 1.6 times the mass of cement) and stir it evenly, to obtain the said cement-based silica aerogel-diatomite composite thermal insulation material.
Embodiment 13
A composite thermal insulation material (13#), which is a cement-based silica aerogel-diatomite composite thermal insulation material, includes the following components in terms of mass fraction:
Silica aerogel-diatomite material 50 parts
Cement 100 parts
Polypropylene (PP) fiber 0.6 parts
Coupling agent 4.5 parts
Cellulose ether 0.75 parts
Redispersible emulsion powder 4.2 parts.
Wherein: the said coupling agent is a liquid silane coupling agent, the said redispersible emulsion powder is a solid powder, the said PP fiber has a length of 6 mm - 12 mm, and the said cellulose ether is a solid powder of hydroxypropyl methyl cellulose with a viscosity of 100000 MPa •S.
A preparation method of the said composite thermal insulation material includes the following steps (as shown in Figure 7):
1) Mix fly ash and sodium carbonate according to the mass ratio of 1:1.3 and then grind the mixture to below 200 mesh, then calcinate the mixture at 770°Cfor 2h to obtain the calcined mixture;
2) Hydrolyze the calcined mixture with hydrofluoric acid, then adjust the pH of the resulted solution to 7 with 5mol/L aqueous ammonia solution, and then leave the solution to stand still and age for l d to form a silica gel;
3) Wash the silica gel with deionized water and ethanol several times in sequence, then add 35 mass parts of diatomite into 15 mass parts of silica gel, stir the mixture evenly and place it under vacuum conditions to have negative pressure adsorption for 24h until the diatomite completely enters the gel, to get the composite material;
4) According to the volume ratio of 8:1.8:1, mix n-hexane, trimethylchlorosilane and ethanol to obtain the modification solution, and then immerse the composite material in the modification solution for modification, every 12h to replace the modification solution until the composite material is suspended or floating in the modification solution, then take it out, wash with n-hexane to obtain the modified composite material;
5) Dry the modified composite material in stages, dry it at 40°C for 12 hours and 130°C for 2 hours, and repeat the drying until constant weight to obtain the silica aerogel-diatomite material;
6) Dry and mix the silica aerogel-diatomite material, cement, PP fiber, the coupling agent, cellulose ether and redispersible emulsion powder according to a certain ratio, and then add water into the mixture (the mass of water added is 1.4 times the mass of cement) and stir it evenly, to obtain the said cement-based silica aerogel-diatomite composite thermal insulation material.
The cement-based silica aerogel-diatomite composite thermal insulation materials (1#-13#) prepared in Embodiment cases 1-13 are off-white. For the raw materials used in Embodiment cases 1-9 and the cement-based silica aerogel-diatomite composite thermal insulation materials prepared in the cases, various parameter and performance analyses include:
1. Analyze the microstructure of diatomite and silica aerogel-diatomite materials with scanning electron microscope;
2. Measure the specific surface area and pore structure of the raw materials and silica aerogel-diatomite materials with an automatic specific surface area analyzer to determine the composite effect of diatomite and silica aerogel and whether the diatomite pores are effectively filled by silica aerogel;
3. Use Fourier transform infrared spectroscopy and X-ray fluorescence spectroscopy to study and analyze the chemical composition of silica aerogel-diatomite materials;
4. Use DRE-2C non-steady thermal sensor to analyze and compare the thermal conductivity of the cement-based silica aerogel-diatomite composite thermal insulation material and the cement slurry test block without thermal insulation material, and observe the effect of the silica aerogel-diatomite material on the thermal insulation performance of cement-based materials;
5. Use the cement constant stress flexural and compressive testing machine to measure the compressive strength of the cement-based silica aerogel-diatomite composite thermal insulation material.
6. Measure the changes of the thermal conductivity and compressive strength of the materials under water-saturated and dried-to-constant-weight conditions, and analyze the influence of the humid environment on the use performance of the cement-based silica aerogel-diatomite composite thermal insulation material.
The test results show that the content of silica aerogel-diatomite in the cement-based silica aerogel-diatomite composite thermal insulation material has a roughly negative correlation with the thermal conductivity and compressive strength of the composite thermal insulation material; the content of diatomite in the cement-based silica aerogel-diatomite composite thermal insulation material has a positive correlation with the density, thermal conductivity and compressive strength of the composite thermal Insulation material, but is negatively correlated with the specific surface area . At the same time, in a humid environment, the thermal conductivity of the cement-based silica aerogel-diatomite composite thermal insulation material increases significantly, and its compressive strength decreases by about 13%, as shown in Figure 1-6:
Figure 1 shows the scanning electron microscope photographs of the surface morphology of the raw material diatomite as well as the silica aerogel-diatomite materials prepared in Embodiment cases 1-4, where a is diatomite; b, c, and d are the silica aerogel-diatomite materials prepared in Embodiment cases 1-3 in sequence; both e and f are silica aerogel-diatomite materials prepared in Embodiment case 4. From microstructure diagrams, it can be seen that diatomite has a porous pie-like structure whose surface has a sieve-like pore distribution. After the silica aerogel-diatomite material is formed, the pores of diatomite decrease, and its specific surface area is greatly reduced. It can be seen from the figure that, as the amount of diatomite increases, silica aerogel cannot completely fill the pores of diatomite and some pores are exposed.
Figure 2 shows the nitrogen adsorption and desorption curves of the raw material diatomite as well as the silica aerogel-diatomite materials prepared in Embodiment cases 1-4. It can be seen from the test results that the specific surface area of diatomite is relatively small. It is known that the specific surface area of silica aerogel is large. The most probable pore diameter of diatomite is about 4nm. It can be seen from the nitrogen adsorption and desorption isotherm that most of the pores in diatomite are micropores. As the mass ratio of diatomite to silica aerogel increases, the specific surface area of the silica aerogel-diatomite material decreases from 554.465 m2/g as seen in the sample prepared in Embodiment case 1 to 84.009 m 2/g as seen in the sample prepared in Embodiment case 4, getting closer and closer to the specific surface area of diatomite, while its pore diameter is reduced to about 4nm and its nitrogen adsorption and desorption isotherm is a type I isotherm, indicating that the silica aerogel-diatomite material is a microporous material and its most probable pore diameter is about 2.2nm, in line with the pore structure characteristics of silica aerogel. Combined with SEM photos, this indicated that silica aerogel can effectively fill the pores of diatomite and can be effectively adsorbed under negative pressure to form silica aerogel-diatomite material. As the amount of diatomite increases, the specific surface area of silica aerogel-diatomite material becomes smaller and smaller. This is consistent with the analysis results of scanning electron microscope photos.
Figure 3 shows the XRD test charts of the raw material diatomite, the silica aerogel prepared without diatomite as well as the silica aerogel-diatomite materials prepared in Embodiment cases 1, 2 and 4. It can be seen from thefigure that the different peak intensities of the silica aerogel-diatomite materials are caused by the different contents of diatomite in the silica aerogel-diatomite materials. The XRD diagrams of the silica aerogel-diatomite materials have no new peaks compared with those of diatomite and the silica aerogel prepared without diatomite. This indicates that adding the diatomite negative pressure adsorption after gelation did not produce any new substances in the present invention.
Figure 4 shows the FT-IR test charts of the raw material diatomite, the silica aerogel prepared without diatomite as well as the silica aerogel-diatomite materials prepared in Embodiment cases 1, 2 and 4. It can be seen that the figure is the superposition of the FT-IR test charts of diatomite and silica aerogel. At the same time, it can be seen from the figure that there is no new peak appearing. Therefore, no new substances are generated in the silica aerogel-diatomite material formed by adding diatomite into silica aerogel during the preparation process of silica aerogel, and the structure of the silica aerogel-diatomite material remains unchanged and its thermal insulation performance is stable.
Figure 5 shows the thermal conductivity analysis diagrams of the cement slurry test block and 1#-9# samples prepared in Embodiment cases 1-9. Figure 5(a) is the thermal conductivity analysis diagram of the cement slurry test block and 1#-4# samples prepared in Embodiment cases 1-4. Through the comparison between the wet environment and the completely dry environment in the figure, it can be seen that after the cement-based material is added with the silica aerogel- diatomite material, its thermal conductivity is significantly reduced no matter whether it is in the wet care condition or under constant temperature to constant weight condition. This indicates that the addition of silica aerogel-diatomite material can significantly improve the thermal insulation performance of cement. When other conditions remain unchanged, with the increase of diatomite content in silica aerogel-diatomite materials, the thermal conductivity of cement-based silica aerogel-diatomite materials gradually rises, as shown in 1# to 4#. This is because silica aerogel cannot completely cover the pores of diatomite as the diatomite content increases. When heat is transmitted, it is transmitted along the diatomite with higher thermal conductivity, forming a thermal bridge effect, leading to a significant increase in the thermal conductivity of the composite material. Figure 5(b) is the thermal conductivity analysis diagram of 5#-9# samples prepared in Embodiment cases 5-9. From the above test results, it can be concluded that, with the increasing content of silica aerogel-diatomite material, the thermal conductivity of cement-based silica aerogel-diatomite materials shows a decreasing trend, as shown in 5#-8#, but with different decrease rates. The thermal conductivity of 5#-8# samples prepared in Embodiment cases 5-9 rises significantly after water absorption, indicating that water absorption has an adverse effect on the reduction of thermal conductivity.
Figure 6 shows the compressive strength performance analysis diagrams of the cement slurry test block as well as 1#-9# samples prepared in Embodiment cases 1-9. Figure 6(a) is the compressive strength performance analysis diagrams of the cement slurry test block and as well as 1#-4# samples prepared in Embodiment cases 1-4. According to the above test results, it can be seen that the compressive strength of the cement-based silica aerogel-diatomite material is significantly lower than that of the cement slurry test block. After the cement-based composite material is added with silica aerogel-diatomite material, its compressive strength is significantly reduced. With the increase of diatomite content in the silica aerogel-diatomite material, the compressive strength of 1#-4# samples gradually increases, because the strength of diatomite is greater than that of silica aerogel. Figure 6(b) is the compressive strength performance analysis diagrams of 5#-9# samples prepared in Embodiment cases 5-9. Their compressive strength under humid conditions is about 13% lower than that under complete dry conditions. Under dry conditions, the minimum compressive strength of the samples is about 3MPa, and the maximum is 5.1MPa. After the samples are saturated with water, their compressive strength is 1.6-4.3MPa.
Figure 7 shows the preparation flowchart of the cement-based silica aerogel / diatomite composite thermal insulation material.
The basic principle, main features and advantages of the present invention are described above. Technicians in the industry should understand that the present invention is not limited by the above embodiment cases. The above embodiment cases and description only explain the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention can also have various changes and improvements that shall all fall into the claimed scope of the present invention. The appended claims within the scope of the present invention are defined by equivalents. Using the present invention's thermal insulation materials as the thermal insulation materials of buildings can effectively reduce heat transfer inside and outside buildings, decrease indoor temperature fluctuations, achieve indoor thermal insulation, reduce the use of building heating or air conditioning and improve the energy efficiency of buildings.
The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that such prior art forms part of the common general knowledge.
It will be understood that the terms "comprise" and "include" and any of their derivatives (e.g. comprises, comprising, includes, including) as used in this specification, and the claims that follow, is to be taken to be inclusive of features to which the term refers, and is not meant to exclude the presence of any additional features unless otherwise stated or implied.
In some cases, a single embodiment may, for succinctness and/or to assist in understanding the scope of the disclosure, combine multiple features. It is to be understood that in such a case, these multiple features may be provided separately (in separate embodiments), or in any other suitable combination. Alternatively, where separate features are described in separate embodiments, these separate features may be combined into a single embodiment unless otherwise stated or implied. This also applies to the claims which can be recombined in any combination. That is a claim may be amended to include a feature defined in any other claim. Further a phrase referring to "at least one of' a list of items refers to any combination of those items, including single members. As an example, "at least one of: a, b, or c" is intended to cover: a,b, c, a-b, a-c,b-c, and a-b-c.
It will be appreciated by those skilled in the art that the disclosure is not restricted in its use to the particular application or applications described. Neither is the present disclosure restricted in its preferred embodiment with regard to the particular elements and/or features described or depicted herein. It will be appreciated that the disclosure is not limited to the embodiment or embodiments disclosed, but is capable of numerous rearrangements, modifications and substitutions without departing from the scope as set forth and defined by the following claims.
Claims (6)
1. A composite thermal insulation material, wherein the composite thermal insulation material is a cement-based silica aerogel-diatomite composite thermal insulation material, and includes the following components by mass fraction:
Silica aerogel-diatomite material 40-70 parts
Cement 100 parts
Polypropylene (PP) fiber 0.4~1.2 parts
Coupling agent 4.2-5.1 parts
Cellulose ether 0.56~1.2 parts
Redispersible emulsion powder 2.8-5.1 parts.
2. The composite thermal insulation material according to claim 1, wherein in the said silica aerogel-diatomite composite thermal insulation material, the specific surface area of silica aerogel is >400m 2 /g when diatomite is not added, and the diatomite is ultrafine diatomite with a particle size of <300 mesh (48[tm);
The length of the said polypropylene fiber is between 6 mm and 12 mm, and the said coupling agent is a liquid silane coupling agent;
The said cellulose ether is a solid powder of hydroxypropyl methylcellulose, with a viscosity of 100000-200000MPa-s and a 80-mesh (178[tm-aperture) sieve pass rate of >98%; the said redispersible emulsion powder is a solid powder, with a 38-mesh (400m-aperture) sieve reject rate of <4%, and a solid content >99%; and/or
The said cement-based silica aerogel-diatomite composite thermal insulation material has a room temperature thermal conductivity of 0.13-0.27W/(m•K) and a compressive strength of 3-5MPa.
3. A preparation method of the composite thermal insulation material according to any one of claims 1 to 2, wherein the method includes the following steps:
1) Mix fly ash with sodium carbonate and grind them, and then calcinate the mixture at high temperature to obtain a calcined mixture;
2) Hydrolyze the calcined mixture with a viable acid, then adjust its pH to 3 - 7, and leave it to stand still and age to form a silica gel;
3) Wash the silica gel with deionized water and then with ethanol several times in sequence, then add diatomite into washed silica gel according to the mass ratio of silica gel to diatomite at
1:1-1:5, then stir the mixture well and place it under vacuum condition to have negative pressure adsorption for 12h ~48h until the diatomite completely enters the gel, so as to obtain a composite material;
4) According to the volume ratio of 8:1:1-8:2:1, mix n-hexane, trimethylchlorosilane and ethanol to obtain a modification solution, and then immerse the composite material in the modification solution for modification, every 8 -24h to replace the modification solution until the composite material is suspended or floating in the modification solution, then take it out, wash with n-hexane to obtain the modified composite material;
) Dry the modified composite material in stages: dry it at room temperature ~ 40°C for 12 - 24 hours, and then dry it at 100-130°C for 2-4 hours, and repeat such drying until constant weight, so as to obtain a silica aerogel-diatomite material;
6) Diatomite material, cement, polypropylene (PP) fiber, coupling agent, cellulose ether and redispersible emulsion powder are mixed under dry conditions according to the following proportion,
Silica aerogel-diatomite material 40-70 parts
Cement 100 parts
Polypropylene (PP) fiber 0.4~1.2 parts
Coupling agent 4.2-5.1 parts
Cellulose ether 0.56~1.2 parts
Redispersible emulsion powder 2.8-5.1 parts,
and then water is added to the mixture and stirred evenly to obtain the cement-based silica aerogel-diatomite composite insulation material.
4. The preparation method of the composite thermal insulation material according to claim 3, wherein the mixing and grinding of fly ash and sodium carbonate mentioned in step 1) refer to mixing fly ash and sodium carbonate at a mass ratio of 1:0.8 - 1:1.5 and then grinding the mixture to below 200 mesh (74[tm),
The particle size of the fly ash described in step 1) is <200 mesh (74[m); and the high-temperature calcination treatment described in step 1) refers to the high temperature calcination treatment at 750-850°C for 1.5-2h,
The viable acid described in step 2) is sulfuric acid, hydrochloric acid, hydrofluoric acid, phosphoric acid, oxalic acid or nitric acid; the adjusting reagent used to adjust the pH to 3-7 afterwards described in step 2) is ammonia water, and the standing aging time described in step 2) is one to two days, and/or
In "then water is added to the mixture and stirred evenly" as described in step 6), the mass of the added water is 1-2 times the mass of cement.
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| CN110627523A (en) | 2019-12-31 |
| CN110627523B (en) | 2020-11-03 |
| AU2019467669A1 (en) | 2021-05-20 |
| WO2021056638A1 (en) | 2021-04-01 |
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