Preparation method of cement-based self-regulating humidity energy-saving environment-friendly building material

Abstract

The application discloses the technical field of green building materials and discloses a preparation method of a cement-based self-humidity-regulating energy-saving and environment-friendly building material; the method obtains a composite mineral carrier by acid activation and calcination treatment of zeolite powder and diatomite, loads lithium chloride, calcium chloride and magnesium nitrate by vacuum pressure impregnation, and performs heat treatment to decompose magnesium nitrate into magnesium oxide nanoparticles, then performs organic-inorganic hybrid modification on the magnesium oxide nanoparticles after hydrolysis of a silane coupling agent and polyethylene imine, finally, gradient heat treatment is performed to construct a nitrogen-doped carbon network and realize microcrystallization of magnesium oxide, and a multi-level pore structure multi-element inorganic salt-organic hybrid nanocrystal composite modified zeolite-diatomite-based humidity-regulating functional material is prepared. The material prepared by the application has excellent passive humidity-regulating performance, good mechanical strength and long-term stability, can effectively reduce building energy consumption, and the process is suitable for industrial production.

Description

Technical Field

[0001] This invention belongs to the field of green building materials technology, specifically relating to a method for preparing a cement-based self-humidifying, energy-saving, and environmentally friendly building material. Background Technology

[0002] Indoor relative humidity is a key environmental parameter affecting human comfort, building durability, and building energy consumption. When indoor relative humidity is maintained between 40% and 70%, human thermal comfort is optimal, the risk of mold growth is minimized, and the lifespan of building materials is effectively guaranteed. However, traditional building envelopes lack autonomous humidity regulation capabilities, relying primarily on active mechanical systems such as air conditioners and dehumidifiers for humidity control. This active control method not only consumes significant amounts of electricity and increases carbon emissions from building operations, but also struggles to achieve uniform humidity distribution within the space, leaving some areas with excessively high or low humidity, impacting the quality of living. Self-regulating humidity materials, through their porous structure and physical adsorption and desorption mechanisms, can automatically respond to changes in ambient humidity without external energy input: absorbing moisture when indoor humidity is too high and releasing moisture when humidity is too low, thus achieving passive humidity buffering and realizing the dual goals of energy saving, reduced consumption, and improved comfort. In recent years, scholars at home and abroad have conducted extensive research on moisture-regulating materials based on porous minerals such as zeolite, diatomite, and sepiolite. They have modified porous minerals through physical compounding, acid activation, and salt impregnation, and have attempted to combine them with cement and other cementing materials to prepare moisture-regulating materials for buildings.

[0003] In existing technologies, the preparation of cement-based moisture-regulating materials mostly adopts a physical compounding strategy, which involves directly mixing porous minerals such as diatomite, zeolite, and sepiolite with cement, or further treating the porous minerals with single modification methods such as acid treatment or salt impregnation before compounding them with cement. While this type of technical solution has a relatively simple process, it still suffers from the following technical defects: First, the interfacial bonding between porous minerals and the cement matrix is ​​weak, and the moisture-regulating components are prone to peeling off during long-term use, leading to a decline in moisture-regulating performance. Second, the pores of porous minerals that have not been deeply activated are easily blocked by cement hydration products, resulting in a significant decrease in effective specific surface area and pore volume, and the moisture-regulating capacity cannot be fully utilized. Third, existing modification methods, such as single acid treatment or salt impregnation, have limited optimization of the pore structure, making it difficult to achieve a multi-level gradient distribution of micropores, mesopores, and macropores, thus limiting the material's response rate and buffer capacity over a wide humidity range. Fourth, there is an inherent contradiction between moisture-regulating performance and mechanical properties; high-dosage porous materials often lead to a significant reduction in the strength of cement-based materials, making it difficult to meet the basic mechanical performance requirements of building structures or plaster layers. Fifth, conventional salt-modified materials face the problem of soluble salt migration and precipitation in practical applications, leading to surface blooming and continuous decline in moisture-regulating performance, resulting in insufficient long-term stability. Therefore, how to achieve precise control over the pore structure of porous minerals while ensuring good mechanical properties, while enhancing the interfacial bonding strength between modified materials and cement matrix, and ensuring performance stability during long-term use, is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing cement-based self-humidifying, energy-saving, and environmentally friendly building materials.

[0005] In a first aspect, the present invention provides a method for preparing a cement-based self-humidifying, energy-saving, and environmentally friendly building material, comprising the following steps: S1. By weight, 100 parts of silicate cement, 30-50 parts of multi-level porous structure multi-element inorganic salt-organic hybrid nanocrystalline composite modified zeolite-diatomite-based moisture-regulating functional material, 50-80 parts of quartz sand, 15-25 parts of fly ash, 8-15 parts of magnesium aluminum hydrotalcite, and 0.3-0.8 parts of hydroxypropyl methylcellulose are sequentially added into a mixer and mixed to obtain a dry mixture. S2. Add 0.8-1.5 parts of polycarboxylate superplasticizer, 2-4 parts of ethylene-vinyl acetate copolymer, and 3-6 parts of nano-silica sol to 45-65 parts of deionized water in sequence, disperse them, and obtain a mixture. S3. Add the dry mixture to the liquid mixture and stir to obtain a slurry; pour the slurry into the mold to obtain a casting mold; S4. Allow the cast mold to stand for curing; remove the mold to obtain the demolded specimen; continue curing the demolded specimen.

[0006] In this invention, the preparation of cement-based self-humidifying energy-saving and environmentally friendly building materials achieves humidity control through the synergistic effect of multi-level porous structure multi-element inorganic salt-organic hybrid nanocrystalline composite modified zeolite-diatomite-based humidity-regulating functional materials and cement matrix. Calcined hydrotalcite undergoes an adsorption reaction with calcium hydroxide in the early stages of cement hydration. Its layered structure fills the pores at the cement paste interface, increasing matrix density and reducing microcracks, while simultaneously providing stable anchoring points for the multi-level porous structure multi-element inorganic salt-organic hybrid nanocrystalline composite modified zeolite-diatomite-based humidity-regulating functional materials. A two-stage humidity control strategy is adopted during the curing stage: an initial high-humidity environment ensures full cement hydration, forming dense hydration products (such as CSH gel), providing a uniformly dispersed substrate for the multi-level porous structure multi-element inorganic salt-organic hybrid nanocrystalline composite modified zeolite-diatomite-based humidity-regulating functional materials; subsequently, curing under low-humidity conditions effectively inhibits the migration of soluble salt components such as lithium chloride and calcium chloride to the surface, avoiding efflorescence caused by precipitation. The hierarchical porous structure of the multi-element inorganic salt-organic hybrid nanocrystalline composite modified zeolite-diatomite-based humidity-regulating functional material forms microscale humidity-regulating channels within the cement matrix. The phase transition process of salts within the channels (salt dissolves and absorbs moisture during absorption, and crystallizes and releases moisture during release) buffers humidity. Meanwhile, the organic-inorganic hybrid layer enhances the interfacial bonding strength between the pore walls and the cement matrix, preventing channel failure due to interfacial weakening during humidity cycles. This synergistic mechanism ensures the stability of the material's moisture absorption and release properties under long-term humidity variations. Simultaneously, interface optimization between cement hydration products and the multi-element inorganic salt-organic hybrid nanocrystalline composite modified zeolite-diatomite-based humidity-regulating functional material improves overall mechanical properties. The organic-inorganic hybrid network also promotes a uniform distribution of the humidity gradient within the channels, avoiding localized over- or under-humidity, achieving a balance between energy conservation, environmental protection, and functional stability, significantly extending the material's service life.

[0007] According to a preferred embodiment of the present invention, in step S1, the mixing time is 15-30 min.

[0008] According to a preferred embodiment of the present invention, in step S2, the dispersion processing time is 5-8 minutes.

[0009] According to a preferred embodiment of the present invention, in step S3, the stirring and mixing time is 3-5 minutes.

[0010] According to a preferred embodiment of the present invention, in step S4, the static curing time is 24-30 hours.

[0011] According to a preferred embodiment of the present invention, the preparation steps of the multi-level porous structure multi-element inorganic salt-organic hybrid nanocrystal composite modified zeolite-diatomite-based humidity-regulating functional material include: A1. By weight, mix 30-50 parts of zeolite powder with 6-17 parts of diatomaceous earth to obtain a composite mineral precursor; place the composite mineral precursor in 160-280 parts of hydrochloric acid solution and stir at 73-77℃; after treatment, vacuum filter to obtain a solid; wash the solid with deionized water to obtain a washed solid; place the washed solid in a vacuum drying oven and dry at 103-107℃ to obtain an acid-activated composite mineral; place the acid-activated composite mineral in a muffle furnace and calcine at 390-410℃, then allow it to cool naturally to room temperature to obtain the calcined product; grind and sieve the calcined product to obtain a composite mineral carrier. A2. Place 100 parts of the composite mineral carrier in a vacuum impregnation apparatus; under vacuum conditions, inject a first impregnation solution composed of 3.5-4.5 parts of anhydrous lithium chloride, 3.5-4.5 parts of anhydrous calcium chloride, and 28-36 parts of deionized water into the vacuum impregnation apparatus to obtain a mixture; transfer the mixture to a sealed reaction vessel and impregnate it at 83-87℃ to obtain an impregnated mixture; transfer the impregnated mixture to a rotary evaporator and concentrate it under reduced pressure at 68-72℃ to obtain the product; [The text abruptly ends here, likely due to an incomplete sentence or missing information.] The modified composite mineral was dried in a forced-air drying oven at 118-122℃ to obtain a modified composite mineral. 100 parts of the modified composite mineral were immersed in a solution composed of 45-55 parts magnesium nitrate and 135-165 parts deionized water, and ultrasonically assisted impregnation was performed in a constant temperature water bath at 58-62℃. The impregnation was continued to stand to obtain an impregnation mixture. The impregnation mixture was dried at 104-106℃, and then placed in a muffle furnace and heated to 290-310℃ for heat treatment. After cooling to room temperature in the furnace, the mixture was ground and sieved to obtain a multi-element inorganic salt gradient impregnation modified product. A3. Disperse 100 parts of the multi-element inorganic salt gradient impregnation modified product in 270-330 parts of anhydrous ethanol and stir to obtain a dispersion. Mix 3-5 parts of γ-glycidyl etheroxypropyltrimethoxysilane with 15-25 parts of deionized water, adjust the pH to 4.0-5.0 with 0.1-0.3 parts of glacial acetic acid, and hydrolyze at room temperature to obtain a hydrolyzed silane solution. Add the hydrolyzed silane solution dropwise to the dispersion. After the addition is complete, continue the reaction under ice-water bath conditions. Then remove the ice-water bath, raise the temperature to 58-62℃, add a solution composed of 1.8-2.2 parts of polyethyleneimine and 160-240 parts of deionized water, and continue the reaction at 58-62℃. After the reaction is complete, centrifuge to separate the solid product, wash the solid product with anhydrous ethanol, and dry it in a vacuum drying oven at 58-62℃ to obtain an organic-inorganic hybrid pore-modified composite modified material. A4. Place 100 parts of the organic-inorganic hybrid pore-modified composite material in a tube furnace and, under nitrogen atmosphere protection, heat to 148-152℃ and hold at that temperature; heat to 348-352℃ and hold at that temperature; then heat to 548-552℃ and hold at that temperature; under nitrogen atmosphere protection, cool to room temperature to obtain the cooled product; grind and sieve the cooled product.

[0012] In this invention, the preparation of multi-level porous inorganic salt-organic hybrid nanocrystalline composite modified zeolite-diatomite-based humidity-regulating functional materials is based on a three-step core mechanism: mineral activation, salt gradient impregnation, and organic-inorganic hybridization. Natural zeolite and diatomite are treated with an acidic solution, undergoing a proton exchange reaction. Exchangeable cations in the zeolite framework are replaced by hydrogen ions, while impurity mineral phases in the diatomite dissolve, forming a highly surface-active activation intermediate. This process significantly opens the microporous structure of the zeolite, increasing its specific surface area and pore accessibility. Subsequently, lithium chloride and calcium chloride solutions permeate into the mineral micropores under vacuum impregnation conditions through capillary action, utilizing the hydrophilicity of the pores to achieve the directional distribution of salt ions. After impregnation with magnesium nitrate solution, heat treatment completely decomposes the magnesium nitrate into magnesium oxide nanoparticles. These particles uniformly nucleate and grow on the inner walls of the pores, anchoring to the mineral framework through chemical bonding, forming a salt-oxide composite structure that effectively inhibits the migration and precipitation of salts under humidity changes. The key steps lie in the hydrolysis and hybridization of the silane coupling agent: γ-glycidoxypropyltrimethoxysilane hydrolyzes under acidic conditions, and its silane groups condense with the silanol groups on the mineral surface to form siloxane bonds. Simultaneously, the epoxy groups undergo ring-opening addition reactions with the amino groups of polyethyleneimine, constructing an organic-inorganic hybrid network rich in amino functional groups. During gradient heat treatment, polyethyleneimine gradually carbonizes to form a nitrogen-doped carbon framework, which works synergistically with magnesium oxide nanoparticles to induce a microcrystalline transformation of the mineral channels, forming a multi-level gradient structure of micropores, mesopores, and macropores. This structure achieves efficient humidity buffering through the phase transition of salts within the channels (dissolving and absorbing moisture during hygroscopic absorption, and crystallizing and releasing moisture during dehumidification). The enhancement of the organic-inorganic interface significantly improves the stability of the channel structure during cycling, preventing collapse caused by mechanical stress.

[0013] According to a preferred embodiment of the present invention, in step A1, the calcination time at 390-410°C is 2-4 hours.

[0014] According to a preferred embodiment of the present invention, in step A2, the heat treatment time at 290-310°C is 3-5 hours.

[0015] According to a preferred embodiment of the present invention, in step A3, the reaction is continued at 58-62°C for 6-8 hours.

[0016] According to a preferred embodiment of the present invention, in step A4, the time for constant temperature treatment at 548-552°C is 1-2 hours.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention achieves a significant improvement in humidity regulation performance. Through the synergistic effect of four steps—precursor activation treatment, gradient impregnation with multi-element inorganic salts, organic-inorganic hybrid pore modification, gradient heat treatment, and nanocrystallization—a multi-level pore structure with a gradient distribution of micropores, mesopores, and macropores is constructed within the zeolite-diatomite composite mineral. Simultaneously, the inner walls of the pores are loaded with lithium chloride, calcium chloride, magnesium oxide nanocrystals, and a nitrogen-doped carbon network. The synergistic effect of the multi-level pore structure and multiple functional layers enables the material to exhibit excellent moisture absorption and release capabilities over a wide humidity range, achieving an excellent moisture buffering value.

[0018] (2) This invention achieves synergistic optimization of humidity-regulating performance and mechanical properties. By constructing an organic-inorganic hybrid network structure on the surface of the multi-level porous multi-element inorganic salt-organic hybrid nanocrystalline composite modified zeolite-diatomite-based humidity-regulating functional material, a chemical bond interface is formed between the multi-level porous multi-element inorganic salt-organic hybrid nanocrystalline composite modified zeolite-diatomite-based humidity-regulating functional material and the cement matrix, effectively mitigating the weakening effect of the interface transition zone. At the same time, the polyethyleneimine and silane coupling agent segments in the organic-inorganic hybrid network can complex with calcium ions during cement hydration, promoting the uniform growth of hydrated calcium silicate gel on the surface of the modified material. The magnesium aluminum hydrotalcite added to the formulation can adsorb calcium hydroxide to generate hydrated calcium silicate and hydrated calcium aluminate, further filling the interface pores. Under the combined effect of the above mechanisms, the material of the present invention can still maintain good mechanical properties under high dosage conditions of multi-level porous structure multi-element inorganic salt-organic hybrid nanocrystal composite modified zeolite-diatomite based humidity regulating functional material, which fully meets the requirements for use of building interior wall plastering materials.

[0019] (3) This invention exhibits excellent long-term stability and energy-saving and environmental benefits. Multiple anchoring mechanisms effectively inhibit the migration of soluble salts: vacuum pressure impregnation allows salt components to penetrate deep into the mineral pores; an organic-inorganic hybrid network forms a physical coating; magnesium oxide nanoparticles generated by magnesium nitrate heat treatment form a strong chemical bond with the inner wall of the pores; and a nitrogen-doped carbon network formed by partial carbonization of polyethyleneimine further enhances the overall stability of the pore structure. Accelerated aging tests show that the moisture absorption performance degradation rate of the material of this invention is significantly lower than that of existing technologies. Furthermore, the material of this invention effectively reduces the energy consumption of building air conditioning dehumidification through passive humidity control, while also utilizing a large amount of industrial by-products and natural mineral resources, reducing cement usage, and lowering carbon emissions during the production process of building materials, thus possessing significant energy-saving and environmental benefits. Detailed Implementation

[0020] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0021] Example 1 This embodiment provides a method for preparing a cement-based self-humidifying, energy-saving, and environmentally friendly building material, including the following steps: S1. 100g silicate cement, 40g multi-level porous structure multi-element inorganic salt-organic hybrid nanocrystalline composite modified zeolite-diatomite-based humidity regulating functional material, 65g quartz sand, 20g fly ash, 12g magnesium aluminum hydrotalcite, and 0.5g hydroxypropyl methylcellulose are sequentially added into a three-dimensional mixer and mixed at 20 rpm for 15 minutes to obtain a dry mixture.

[0022] S2. Add 1.2g of polycarboxylate superplasticizer, 3g of ethylene-vinyl acetate copolymer, and 4.5g of nano-silica sol to 55g of deionized water in sequence, and disperse at 900rpm for 6min to obtain a mixture.

[0023] S3. Add the dry mixture to the liquid mixture and use a planetary mixer to mix at a low speed of 45 rpm for 2 minutes, and then mix at a high speed of 125 rpm for 3 minutes to obtain a slurry. Pour the slurry into a 300mm×300mm×10mm mold and vibrate at 55Hz for 45 seconds while pouring to obtain a cast mold.

[0024] S4. Place the cast mold in an environment with a temperature of 20℃ and a relative humidity of over 95% for 24 hours to cure. Remove the mold to obtain the demolded specimen. Transfer the demolded specimen to a curing room with a temperature of 20℃ and a relative humidity of 60% for 28 days to obtain the cement-based self-humidifying energy-saving and environmentally friendly building material.

[0025] The preparation steps of multi-level porous structure multi-element inorganic salt-organic hybrid nanocrystal composite modified zeolite-diatomite based humidity-regulating functional materials include: A1. Mix 40g of zeolite powder with 12g of diatomaceous earth to obtain a composite mineral precursor. Place the composite mineral precursor in 220g of 1.2mol / L hydrochloric acid solution and stir at 350rpm for 2.5h at 75℃. After treatment, vacuum filter to obtain a solid. Wash the solid with deionized water until the pH of the filtrate is 6.8 to obtain a washed solid. Place the washed solid in a vacuum drying oven and dry it at 105℃ to constant weight to obtain an acid-activated composite mineral. Place the acid-activated composite mineral in a muffle furnace and calcine it at 400℃ for 2h by heating at 5℃ / min. Let it cool naturally to room temperature with the furnace to obtain the calcined product. Grind the calcined product through a 200-mesh sieve to obtain a composite mineral carrier.

[0026] A2. Place 100g of composite mineral carrier in a vacuum impregnation apparatus, evacuate to an absolute pressure of 1.5kPa and maintain for 30min; under vacuum conditions, inject a first impregnation solution composed of 4.0g anhydrous lithium chloride, 4.0g anhydrous calcium chloride and 32g deionized water into the vacuum impregnation apparatus to obtain a mixture; transfer the mixture to a sealed reaction vessel and perform pressure impregnation treatment at 85℃, with a treatment pressure of 0.35MPa and a treatment time of 4h to obtain an impregnated mixture; transfer the impregnated mixture to a rotary evaporator and perform reduced pressure concentration at 70℃ until the material becomes a viscous paste to obtain the product; The product was placed in a forced-air drying oven and dried at 120℃ for 12 hours to obtain modified composite minerals. 100g of the modified composite minerals were immersed in a 25% magnesium nitrate aqueous solution composed of 50g of magnesium nitrate and 150g of deionized water, and ultrasonically assisted impregnated in a constant temperature water bath at 60℃ for 1 hour. The ultrasonic frequency was 40kHz and the power density was 0.5W / cm². The impregnation was continued for 24 hours to obtain an impregnation mixture. The impregnation mixture was dried at 105℃ for 8 hours, and then placed in a muffle furnace and heat-treated at 300℃ for 3 hours with a heating rate of 2℃ / min. After cooling to room temperature with the furnace, the mixture was ground through a 200-mesh sieve to obtain a multi-element inorganic salt gradient impregnation modified product.

[0027] A3. 100g of the multi-element inorganic salt gradient impregnation modified product was dispersed in 300g of anhydrous ethanol and stirred at 550rpm to obtain a dispersion. 4.0g of γ-glycidyl etheroxypropyltrimethoxysilane was mixed with 20g of deionized water, and the pH was adjusted to 4.5 with 0.2g of glacial acetic acid. The mixture was hydrolyzed at room temperature for 30min to obtain a hydrolyzed silane solution. The hydrolyzed silane solution was added dropwise to the dispersion at 1.5mL / min. After the addition was complete, the reaction was continued under ice-water bath conditions for 2h. Subsequently, the ice-water bath was removed, the temperature was raised to 60℃, and a polyethyleneimine aqueous solution with a mass fraction of approximately 1% (constantly composed of 2.0g of polyethyleneimine and 200g of deionized water) was added. The reaction was continued at 60℃ for 6h. After the reaction was completed, the solid product was collected by centrifugation. The solid product was washed three times with anhydrous ethanol and dried in a vacuum drying oven at 60℃ for 24h to obtain an organic-inorganic hybrid pore-modified composite modified material.

[0028] A4. Place 100g of the organic-inorganic hybrid pore-modified composite material in a tube furnace. Under nitrogen atmosphere protection, heat the material at 1℃ / min to 150℃ and hold for 2h, then heat it at 2℃ / min to 350℃ and hold for 3h, then heat it at 3℃ / min to 550℃ and hold for 1h. Under nitrogen atmosphere protection, cool the material to room temperature at 2℃ / min to obtain the cooled product. Grind the cooled product through a 300-mesh sieve to obtain the multi-level pore structure multi-element inorganic salt-organic hybrid nanocrystal composite modified zeolite-diatomite-based humidity-regulating functional material.

[0029] Example 2 The difference between this embodiment and Embodiment 1 is that this embodiment provides a method for preparing a cement-based self-humidifying, energy-saving, and environmentally friendly building material, including the following steps: S1. 100g silicate cement, 35g multi-level porous structure multi-element inorganic salt-organic hybrid nanocrystalline composite modified zeolite-diatomite-based humidity regulating functional material, 70g quartz sand, 18g fly ash, 10g magnesium aluminum hydrotalcite, and 0.6g hydroxypropyl methylcellulose are sequentially added into a three-dimensional mixer and mixed at 20rpm for 20min to obtain a dry mixture.

[0030] S2. Add 1.0g of polycarboxylate superplasticizer, 2.5g of ethylene-vinyl acetate copolymer, and 4g of nano-silica sol to 52g of deionized water in sequence, and disperse at 850rpm for 7min to obtain a mixture.

[0031] S3. Add the dry mixture to the liquid mixture and use a planetary mixer to mix at a low speed of 45 rpm for 2 minutes, and then mix at a high speed of 125 rpm for 3 minutes to obtain a slurry. Pour the slurry into a 300mm×300mm×10mm mold and vibrate at 52Hz for 50 seconds while pouring to obtain a cast mold.

[0032] S4. Place the cast mold in an environment with a temperature of 20℃ and a relative humidity of over 95% for 26 hours to cure. Remove the mold to obtain the demolded specimen. Transfer the demolded specimen to a curing room with a temperature of 20℃ and a relative humidity of 60% for 28 days to obtain the cement-based self-humidifying energy-saving and environmentally friendly building material.

[0033] The preparation steps of multi-level porous structure multi-element inorganic salt-organic hybrid nanocrystal composite modified zeolite-diatomite based humidity-regulating functional materials include: A1. Mix 35g of zeolite powder with 9g of diatomaceous earth to obtain a composite mineral precursor. Place the composite mineral precursor in 176g of 1.2mol / L hydrochloric acid solution and stir at 320rpm for 2.5h at 74℃. After treatment, vacuum filter to obtain a solid. Wash the solid with deionized water until the pH of the filtrate is 6.7 to obtain a washed solid. Place the washed solid in a vacuum drying oven and dry it at 104℃ to constant weight to obtain an acid-activated composite mineral. Place the acid-activated composite mineral in a muffle furnace and calcine it at 395℃ for 2.5h with a heating rate of 5℃ / min. Allow it to cool naturally to room temperature to obtain the calcined product. Grind the calcined product through a 200-mesh sieve to obtain a composite mineral carrier.

[0034] A2. Place 100g of composite mineral carrier in a vacuum impregnation apparatus, evacuate to an absolute pressure of 1.2kPa and maintain for 30min; under vacuum conditions, inject a first impregnation solution composed of 3.8g anhydrous lithium chloride, 3.8g anhydrous calcium chloride and 30g deionized water into the vacuum impregnation apparatus to obtain a mixture; transfer the mixture to a sealed reaction vessel and perform pressure impregnation treatment at 84℃, with a treatment pressure of 0.32MPa and a treatment time of 4h to obtain an impregnated mixture; transfer the impregnated mixture to a rotary evaporator and perform reduced pressure concentration at 69℃ until the material becomes a viscous paste to obtain the product; the product... The material was placed in a forced-air drying oven and dried at 119℃ for 12 hours to obtain modified composite minerals. 100g of the modified composite minerals were immersed in a 25% magnesium nitrate aqueous solution composed of 48g of magnesium nitrate and 144g of deionized water, and ultrasonically assisted impregnated in a constant temperature water bath at 59℃ for 1 hour. The ultrasonic frequency was 40kHz and the power density was 0.5W / cm². The impregnation was continued for 24 hours to obtain an impregnation mixture. The impregnation mixture was dried at 104℃ for 8 hours, and then placed in a muffle furnace and heat-treated at 2℃ / min to 295℃ for 3.5 hours. After cooling to room temperature in the furnace, the mixture was ground through a 200-mesh sieve to obtain a multi-element inorganic salt gradient impregnation modified product.

[0035] A3. 100g of the multi-element inorganic salt gradient impregnation modified product was dispersed in 290g of anhydrous ethanol and stirred at 520rpm to obtain a dispersion. 3.5g of γ-glycidyl etheroxypropyltrimethoxysilane was mixed with 18g of deionized water, and the pH was adjusted to 4.3 with 0.15g of glacial acetic acid. The mixture was hydrolyzed at room temperature for 30min to obtain a hydrolyzed silane solution. The hydrolyzed silane solution was added dropwise to the dispersion at 1.2mL / min. After the addition was complete, the reaction was continued under ice-water bath conditions for 2h. Subsequently, the ice-water bath was removed, the temperature was raised to 59℃, and a polyethyleneimine aqueous solution with a mass fraction of approximately 1% (1.9g of polyethyleneimine and 190g of deionized water) was added. The reaction was continued at 59℃ for 7h. After the reaction was completed, the solid product was collected by centrifugation. The solid product was washed three times with anhydrous ethanol and dried in a vacuum drying oven at 59℃ for 24h to obtain an organic-inorganic hybrid pore-modified composite modified material.

[0036] A4. Place 100g of the organic-inorganic hybrid pore-modified composite material in a tube furnace. Under nitrogen atmosphere protection, heat the material at 1℃ / min to 149℃ and hold for 2h, then heat it at 2℃ / min to 349℃ and hold for 3h, then heat it at 3℃ / min to 549℃ and hold for 1.2h. Under nitrogen atmosphere protection, cool the material to room temperature at 2℃ / min to obtain the cooled product. Grind the cooled product through a 300-mesh sieve to obtain the multi-level pore structure multi-element inorganic salt-organic hybrid nanocrystal composite modified zeolite-diatomite-based humidity-regulating functional material.

[0037] Example 3 The difference between this embodiment and Embodiment 1 is that this embodiment provides a method for preparing a cement-based self-humidifying, energy-saving, and environmentally friendly building material, including the following steps: S1. 100g silicate cement, 45g multi-level porous structure multi-element inorganic salt-organic hybrid nanocrystalline composite modified zeolite-diatomite-based humidity regulating functional material, 60g quartz sand, 22g fly ash, 14g magnesium aluminum hydrotalcite, and 0.4g hydroxypropyl methylcellulose are sequentially added into a three-dimensional mixer and mixed at 20rpm for 25min to obtain a dry mixture.

[0038] S2. Add 1.4g of polycarboxylate superplasticizer, 3.5g of ethylene-vinyl acetate copolymer, and 5g of nano-silica sol to 60g of deionized water in sequence, and disperse at 950rpm for 5.5min to obtain a mixture.

[0039] S3. Add the dry mixture to the liquid mixture and use a planetary mixer to mix at a low speed of 45 rpm for 2 minutes, and then mix at a high speed of 125 rpm for 3 minutes to obtain a slurry. Pour the slurry into a 300mm×300mm×10mm mold and vibrate at 58Hz for 40 seconds while pouring to obtain a cast mold.

[0040] S4. Place the cast mold in an environment with a temperature of 20℃ and a relative humidity of over 95% for 28 hours to cure. Remove the mold to obtain the demolded specimen. Transfer the demolded specimen to a curing room with a temperature of 20℃ and a relative humidity of 60% for another 28 days to obtain the cement-based self-humidifying energy-saving and environmentally friendly building material.

[0041] The preparation steps of multi-level porous structure multi-element inorganic salt-organic hybrid nanocrystal composite modified zeolite-diatomite based humidity-regulating functional materials include: A1. Mix 45g of zeolite powder with 15g of diatomaceous earth to obtain a composite mineral precursor. Place the composite mineral precursor in 240g of 1.2mol / L hydrochloric acid solution and stir at 380rpm for 2.5h at 76℃. After treatment, vacuum filter to obtain a solid. Wash the solid with deionized water until the pH of the filtrate is 6.9 to obtain a washed solid. Place the washed solid in a vacuum drying oven and dry it at 106℃ to constant weight to obtain an acid-activated composite mineral. Place the acid-activated composite mineral in a muffle furnace and calcine it at 405℃ for 2h with a heating rate of 5℃ / min. Allow it to cool naturally to room temperature with the furnace to obtain the calcined product. Grind the calcined product through a 200-mesh sieve to obtain a composite mineral carrier.

[0042] A2. Place 100g of composite mineral carrier in a vacuum impregnation apparatus, evacuate to an absolute pressure of 1.8kPa and maintain for 30min; under vacuum conditions, inject a first impregnation solution composed of 4.2g anhydrous lithium chloride, 4.2g anhydrous calcium chloride and 34g deionized water into the vacuum impregnation apparatus to obtain a mixture; transfer the mixture to a sealed reaction vessel and perform pressure impregnation treatment at 86℃, with a treatment pressure of 0.38MPa and a treatment time of 4h to obtain an impregnated mixture; transfer the impregnated mixture to a rotary evaporator and perform reduced pressure concentration at 71℃ until the material becomes a viscous paste to obtain the product; The product was placed in a forced-air drying oven and dried at 121℃ for 12 hours to obtain modified composite minerals. 100g of the modified composite minerals were immersed in a 25% magnesium nitrate aqueous solution composed of 52g of magnesium nitrate and 156g of deionized water, and ultrasonically assisted impregnated in a constant temperature water bath at 61℃ for 1 hour. The ultrasonic frequency was 40kHz and the power density was 0.5W / cm². The impregnation was continued for 24 hours to obtain an impregnation mixture. The impregnation mixture was dried at 106℃ for 8 hours, and then placed in a muffle furnace and heat-treated at 305℃ for 3 hours with a heating rate of 2℃ / min. After cooling to room temperature in the furnace, the mixture was ground through a 200-mesh sieve to obtain a multi-element inorganic salt gradient impregnation modified product.

[0043] A3. 100g of the multi-element inorganic salt gradient impregnation modified product was dispersed in 320g of anhydrous ethanol and stirred at 580rpm to obtain a dispersion. 4.5g of γ-glycidyl etheroxypropyltrimethoxysilane was mixed with 22g of deionized water, and the pH was adjusted to 4.7 with 0.25g of glacial acetic acid. The mixture was hydrolyzed at room temperature for 30min to obtain a hydrolyzed silane solution. The hydrolyzed silane solution was added dropwise to the dispersion at 1.8mL / min. After the addition was complete, the reaction was continued under ice-water bath conditions for 2h. Subsequently, the ice-water bath was removed, the temperature was raised to 61℃, and a polyethyleneimine aqueous solution with a mass fraction of approximately 1% (constantly composed of 2.1g of polyethyleneimine and 210g of deionized water) was added. The reaction was continued at 61℃ for 6.5h. After the reaction was completed, the solid product was collected by centrifugation. The solid product was washed three times with anhydrous ethanol and dried in a vacuum drying oven at 61℃ for 24h to obtain an organic-inorganic hybrid pore-modified composite modified material.

[0044] A4. Place 100g of the organic-inorganic hybrid pore-modified composite material in a tube furnace. Under nitrogen atmosphere protection, heat the material at 1℃ / min to 151℃ and hold for 2h, then heat it at 2℃ / min to 351℃ and hold for 3h, then heat it at 3℃ / min to 551℃ and hold for 1.5h. Under nitrogen atmosphere protection, cool the material to room temperature at 2℃ / min to obtain the cooled product. Grind the cooled product through a 300-mesh sieve to obtain the multi-level pore structure multi-element inorganic salt-organic hybrid nanocrystal composite modified zeolite-diatomite-based humidity-regulating functional material.

[0045] Comparative Example 1 The difference between this comparative example and Example 1 is that the multi-level porous structure multi-element inorganic salt-organic hybrid nanocrystal composite modified zeolite-diatomaceous earth-based humidity-regulating functional material is replaced with a mixture of unmodified zeolite powder and diatomaceous earth. 40g of zeolite powder and 12g of diatomaceous earth are mixed to form the unmodified zeolite powder and diatomaceous earth mixture, and the rest is the same as in Example 1.

[0046] Comparative Example 2 The difference between this comparative example and Example 1 is that step A2 is omitted in the preparation process of the multi-level porous structure multi-element inorganic salt-organic hybrid nanocrystal composite modified zeolite-diatomite-based humidity regulating functional material; the rest is the same as in Example 1.

[0047] Comparative Example 3 The difference between this comparative example and Example 1 is that step A3 is omitted in the preparation process of the multi-level porous structure multi-element inorganic salt-organic hybrid nanocrystal composite modified zeolite-diatomite-based humidity regulating functional material; otherwise, it is the same as in Example 1.

[0048] In accordance with national and industry standard testing specifications, a series of standardized tests were conducted on the cement-based self-humidifying energy-saving and environmentally friendly building materials described in Examples 1-3 and Comparative Examples 1-3.

[0049] The moisture absorption test method is as follows: Cut the sample into a cube with a side length of 50 mm, and place it in an environment with a temperature of 23±2℃ and a relative humidity of 50±5% for 7 days until constant weight. Record the initial mass of the sample to an accuracy of 0.001 g. Place the constant weight sample in a constant temperature and humidity chamber, control the temperature at 23±2℃ and the relative humidity at 75±3%, and place it for 7 days. Take it out and weigh the sample immediately to an accuracy of 0.001 g. The moisture absorption is calculated according to the formula. The moisture absorption is the mass of the sample after moisture absorption minus the initial mass of the sample, divided by the initial mass of the sample, and multiplied by 100%, expressed as a percentage.

[0050] The moisture release test method is as follows: After the above moisture absorption test is completed, the specimen is placed directly in a constant temperature and humidity chamber, and the temperature is controlled at 23±2℃ and the relative humidity at 33±3%. After 7 days, the specimen is taken out and weighed immediately, accurate to 0.001g. The moisture release is calculated according to the formula, which is the mass of the specimen after moisture absorption minus the mass of the specimen after moisture release, divided by the initial mass of the specimen, multiplied by 100%, and expressed as a percentage.

[0051] The wet buffer value test method is as follows: The sample is cut into a square thin plate with a side length of 100 mm and a thickness of 10 mm. It is placed in an environment with a temperature of 23±2℃ and a relative humidity of 50±5% for 7 days until constant weight. The sample is placed in a constant temperature and humidity chamber, and the temperature is controlled at 23±2℃. The relative humidity is first maintained at 33±3% for 8 hours, and then stepped to 75±3% within 10 minutes and maintained for 8 hours. This is a complete step cycle, and three cycles are performed continuously. During the test, the mass of the sample is weighed every 30 minutes, accurate to 0.001 g, and the stable mass of the sample at the end of each humidity stage is recorded. The wet buffer value is calculated according to the formula. The wet buffer value is the difference between the mass of the sample at the end of the 33% relative humidity stage and the mass at the end of the 75% relative humidity stage in the third cycle, divided by the surface area of ​​the sample, and then divided by the relative humidity change range of 42%. The unit is grams per square meter per percentage of relative humidity.

[0052] The 28-day compressive strength test method is as follows: The specimen is prepared as a prism specimen of 40mm×40mm×160mm. After curing in an environment with a temperature of 20±2℃ and a relative humidity of 95% or higher for 24 hours, it is demolded and transferred to a curing room with a temperature of 20±2℃ and a relative humidity of 60±5% for continued curing until 28 days of age. A pressure testing machine is used for testing, with the loading rate controlled at 2400±200N / s until the specimen fails. The failure load is recorded to an accuracy of 100N. The compressive strength is calculated using the formula: the failure load divided by the bearing area of ​​the specimen, where the bearing area is 40mm×40mm, and the unit is megapascals (MPa).

[0053] The 28-day flexural strength test method is as follows: The specimen is prepared as a prism specimen of 40mm×40mm×160mm. After curing in an environment with a temperature of 20±2℃ and a relative humidity of 95% or higher for 24 hours, it is demolded and transferred to a curing room with a temperature of 20±2℃ and a relative humidity of 60±5% for continued curing until 28 days of age. A three-point bending test is performed using a flexural testing machine with a support span of 100mm and a loading rate controlled at 50±10N / s until the specimen breaks. The breaking load is recorded to an accuracy of 10N. The flexural strength is calculated using the formula: flexural strength is the breaking load multiplied by the support span divided by the specimen width multiplied by the square of the specimen height. The specimen width and height are both 40mm, and the unit is megapascals (MPa).

[0054] The method for testing the moisture absorption decay rate after 10 cycles is as follows: Cut the sample into cubic specimens with a side length of 50 mm. Place them in an environment with a temperature of 23±2℃ and a relative humidity of 50±5% for 7 days until constant weight is achieved. Record the initial mass before moisture absorption to an accuracy of 0.001 g. Place the specimens in a constant temperature and humidity chamber, controlling the temperature at 40±2℃ and the relative humidity at 90±5%. After 12 hours, remove them and immediately transfer them to another constant temperature and humidity chamber, controlling the temperature at 20±2℃ and the relative humidity at 90±5%. The humidity is 30±5%, and the sample is placed for 12 hours, which constitutes one cycle. This cycle is repeated 10 times. After completing 10 cycles, the sample is placed in an environment with a temperature of 23±2℃ and a relative humidity of 50±5% for 24 hours. Then, the moisture absorption after the cycle is measured according to the moisture absorption test method, accurate to 0.001g. The moisture absorption decay rate is calculated according to the formula. The moisture absorption decay rate is the initial moisture absorption minus the moisture absorption after the cycle, divided by the initial moisture absorption, multiplied by 100%, and expressed as a percentage.

[0055] The performance test data above are shown in Table 1.

[0056] Table 1 Performance Test Results

[0057] As can be seen from the above, the comparative analysis of Examples 1-3 and Comparative Examples 1-3 shows that the present invention has successfully solved the three core technical problems that have long existed in existing cement-based moisture-regulating materials.

[0058] First, Comparative Example 1 uses an unmodified mixture of zeolite and diatomaceous earth, with a moisture absorption capacity of only 6.2%, a moisture release capacity of only 5.1%, and a moisture buffer value of only 0.85 g / (m²·%RH). In contrast, Examples 1-3 have moisture absorption capacities of 11.6-13.5%, moisture release capacities of 10.3-11.8%, and moisture buffer values ​​of 1.48-1.75 g / (m²·%RH). This demonstrates that the present invention achieves this through a four-step synergistic process: opening the pore structure of zeolite and diatomaceous earth through precursor activation treatment; gradient impregnation of the inner wall of the pores with multi-element inorganic salts to load magnesium oxide nanoparticles generated by the thermal decomposition of lithium chloride, calcium chloride, and magnesium nitrate; introducing a network structure rich in amino functional groups through organic-inorganic hybrid modification; and constructing a nitrogen-doped carbon network and achieving magnesium oxide microcrystallization through gradient thermal treatment. This process constructs a multi-level pore structure with a gradient distribution of micropores, mesopores, and macropores, significantly improving the moisture absorption capacity and response rate of the material and solving the problem of insufficient moisture regulation performance in the prior art.

[0059] Secondly, Comparative Example 2, which omitted step A2, showed a 28-day compressive strength of 16.5 MPa and a flexural strength of 4.6 MPa, which were lower than the 16.8-20.2 MPa and 4.8-5.5 MPa of Examples 1-3, respectively. Comparative Example 3, which omitted step A3, showed an even more significant decrease in 28-day compressive strength (15.8 MPa) and flexural strength (4.4 MPa). This indicates that the organic-inorganic hybrid network not only endows the material with hydrophilic functional groups, but more importantly, the hydrolysis of the silane coupling agent interacts with the mineral surface... The condensation of silanol groups forms covalent bonds, and the ring-opening addition of the amino group of polyethyleneimine with the epoxy group of the silane coupling agent constructs a stable organic-inorganic hybrid layer on the pore surface. This hybrid layer complexes with calcium ions in the cement matrix, promoting the uniform growth of hydrated calcium silicate gel. At the same time, magnesium aluminum hydrotalcite adsorbs calcium hydroxide to generate hydrated calcium silicate and hydrated calcium aluminate, filling the interfacial pores. This allows the material to maintain good mechanical properties even with a high content of modified materials, solving the contradiction between moisture conditioning performance and mechanical properties in the prior art.

[0060] Furthermore, the moisture absorption decay rate of Comparative Example 1 after 10 cycles was as high as 24.5%, Comparative Example 2 was 15.2%, and Comparative Example 3 was 12.6%, while the decay rate of Examples 1-3 was only 6.2-7.2%. This indicates that the present invention achieves excellent long-term stability through multiple anchoring mechanisms: vacuum pressure impregnation allows lithium chloride and calcium chloride to penetrate deep into the mineral channels rather than just being distributed on the surface; the organic-inorganic hybrid network forms a physical coating that confines the salt components within the channels; the magnesium oxide nanoparticles generated by the complete decomposition of magnesium nitrate during heat treatment at 300°C form a strong chemical bond with the inner wall of the channels; and the nitrogen-doped carbon network formed by the partial carbonization of polyethyleneimine at 350°C further enhances the overall stability of the channel structure. The synergistic effect of multiple mechanisms effectively inhibits the migration and precipitation of soluble salts during long-term use, solving the problems of surface frost and performance degradation that are common in existing salt-modified moisture-regulating materials.

[0061] Based on the above analysis, the multi-level porous structure multi-element inorganic salt-organic hybrid nanocrystal composite modified zeolite-diatomite-based humidity-regulating functional material constructed by the present invention through a four-step synergistic modification process achieves synergistic optimization of humidity regulation performance, mechanical properties and long-term stability after being combined with a cement matrix, providing a complete and feasible technical solution for passive humidity control materials for building interior walls.

Claims

1. A method for preparing a cement-based self-humidifying, energy-saving, and environmentally friendly building material, characterized in that, Includes the following steps: S1. By weight, 100 parts of silicate cement, 30-50 parts of multi-level porous structure multi-element inorganic salt-organic hybrid nanocrystalline composite modified zeolite-diatomite-based moisture-regulating functional material, 50-80 parts of quartz sand, 15-25 parts of fly ash, 8-15 parts of magnesium aluminum hydrotalcite, and 0.3-0.8 parts of hydroxypropyl methylcellulose are sequentially added into a mixer and mixed to obtain a dry mixture. S2. Add 0.8-1.5 parts of polycarboxylate superplasticizer, 2-4 parts of ethylene-vinyl acetate copolymer, and 3-6 parts of nano-silica sol to 45-65 parts of deionized water in sequence, and disperse them to obtain a mixture. S3. Add the dry mixture to the liquid mixture and stir to obtain a slurry; pour the slurry into the mold to obtain a casting mold; S4. Allow the mold to stand for curing; remove the mold to obtain the demolded specimen; Continue curing the demolded specimens; The preparation steps of the multi-level porous structure multi-element inorganic salt-organic hybrid nanocrystalline composite modified zeolite-diatomite-based humidity-regulating functional material include: A1. By weight, 30-50 parts of zeolite powder and 6-17 parts of diatomaceous earth are mixed to obtain a composite mineral precursor. The composite mineral precursor was placed in 160-280 parts of hydrochloric acid solution and stirred at 73-77℃. After treatment, it was vacuum filtered to obtain a solid. The solid was washed with deionized water to obtain a washed solid. The washed solid was placed in a vacuum drying oven and dried at 103-107℃ to obtain an acid-activated composite mineral. The acid-activated composite mineral was placed in a muffle furnace and calcined at 390-410℃, and then naturally cooled to room temperature with the furnace to obtain a calcined product. The calcined product was ground and sieved to obtain a composite mineral carrier. A2. Place 100 parts of the composite mineral carrier in a vacuum impregnation apparatus; under vacuum conditions, inject a first impregnation solution composed of 3.5-4.5 parts of anhydrous lithium chloride, 3.5-4.5 parts of anhydrous calcium chloride, and 28-36 parts of deionized water into the vacuum impregnation apparatus to obtain a mixture; transfer the mixture to a sealed reaction vessel and impregnate it at 83-87℃ to obtain an impregnated mixture; transfer the impregnated mixture to a rotary evaporator and concentrate it under reduced pressure at 68-72℃ to obtain the product; [The text abruptly ends here, likely due to an incomplete sentence or missing information.] The modified composite mineral was dried in a forced-air drying oven at 118-122℃ to obtain a modified composite mineral. 100 parts of the modified composite mineral were immersed in a solution composed of 45-55 parts magnesium nitrate and 135-165 parts deionized water, and ultrasonically assisted impregnation was performed in a constant temperature water bath at 58-62℃. The impregnation was continued to stand to obtain an impregnation mixture. The impregnation mixture was dried at 104-106℃, and then placed in a muffle furnace and heated to 290-310℃ for heat treatment. After cooling to room temperature in the furnace, the mixture was ground and sieved to obtain a multi-element inorganic salt gradient impregnation modified product. A3. Disperse 100 parts of the multi-element inorganic salt gradient impregnation modified product in 270-330 parts of anhydrous ethanol and stir to obtain a dispersion. Mix 3-5 parts of γ-glycidyl etheroxypropyltrimethoxysilane with 15-25 parts of deionized water, adjust the pH to 4.0-5.0 with 0.1-0.3 parts of glacial acetic acid, and hydrolyze at room temperature to obtain a hydrolyzed silane solution. Add the hydrolyzed silane solution dropwise to the dispersion. After the addition is complete, continue the reaction under ice-water bath conditions. Then remove the ice-water bath, raise the temperature to 58-62℃, add a solution composed of 1.8-2.2 parts of polyethyleneimine and 160-240 parts of deionized water, and continue the reaction at 58-62℃. After the reaction is complete, centrifuge to separate the solid product, wash the solid product with anhydrous ethanol, and dry it in a vacuum drying oven at 58-62℃ to obtain an organic-inorganic hybrid pore-modified composite modified material. A4. Place 100 parts of the organic-inorganic hybrid pore-modified composite material in a tube furnace and, under nitrogen atmosphere protection, heat to 148-152℃ and hold at that temperature; heat to 348-352℃ and hold at that temperature; then heat to 548-552℃ and hold at that temperature; under nitrogen atmosphere protection, cool to room temperature to obtain the cooled product; grind and sieve the cooled product.

2. The preparation method of the cement-based self-humidifying energy-saving and environmentally friendly building material according to claim 1, characterized in that, In step S1, the mixing time is 15-30 minutes.

3. The preparation method of the cement-based self-humidifying energy-saving and environmentally friendly building material according to claim 1, characterized in that, In step S2, the dispersion processing time is 5-8 minutes.

4. The preparation method of the cement-based self-humidifying energy-saving and environmentally friendly building material according to claim 1, characterized in that, In step S3, the mixing time is 3-5 minutes.

5. The preparation method of the cement-based self-humidifying energy-saving and environmentally friendly building material according to claim 1, characterized in that, In step S4, the static curing time is 24-30 hours.

6. The preparation method of the cement-based self-humidifying energy-saving and environmentally friendly building material according to claim 1, characterized in that, In step A1, the calcination time at 390-410℃ is 2-4 hours.

7. The preparation method of the cement-based self-humidifying energy-saving and environmentally friendly building material according to claim 1, characterized in that, In step A2, the heat treatment time is 3-5 hours at a temperature of 290-310℃.

8. The preparation method of the cement-based self-humidifying energy-saving and environmentally friendly building material according to claim 1, characterized in that, In step A3, the reaction continues at 58-62℃ for 6-8 hours.

9. The preparation method of the cement-based self-humidifying energy-saving and environmentally friendly building material according to claim 1, characterized in that, In step A4, the temperature is raised to 548-552℃ and kept at that temperature for 1-2 hours.

Images