A high-strength lime-sand polymer building material and preparation method thereof

Abstract

The present invention provides a high-strength fly ash-sand polymer building material and its preparation method, belonging to the technical field of building materials. The fly ash-sand polymer building material comprises calcined fly ash clinker, silica fume, lithium slag, composite nanofiller, coal gangue, steel fiber, a polymerizer, and a polymerization auxiliary. The polymerizer is prepared by mixing an aqueous solution of potassium silicate and an aqueous solution of potassium hydroxide, allowing the mixture to stand for aging after adjusting the pH with citric acid. The polymerization auxiliary is prepared by mixing perfluorohexylethyltriethoxysilane, a silane coupling agent, aminobispropyl polydimethylsiloxane, and diphenylmethane glycidyl ether epoxy resin. The calcined fly ash clinker, silica fume, and lithium slag are wet-ground to prepare a precursor, which lays the foundation for the polymerization reaction. The polymerizer and polymerization auxiliary regulate the reaction process and product structure. The polymerization auxiliary improves workability and uniformity of steel fiber distribution. By optimizing the precursor combination, polymerization formula, preparation process, and curing conditions, a high-strength, high-density, and excellently durable building material is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of new building materials, and particularly relates to a high-strength lime-sand polymer building material and a preparation method thereof. Background Art

[0002] Against the backdrop of accelerating global urbanization and the continued expansion of infrastructure construction, the construction, industrial, and infrastructure sectors are placing ever-more stringent demands on the performance of building materials. Traditional inorganic materials, especially cement and concrete, have long been core building materials. While they have played a crucial role in architectural history, they are gradually revealing their limitations. Their strength is insufficient for modern large-scale projects like super-high-rise buildings and long-span bridges, making them unable to withstand complex loads and extreme environments. In terms of durability, they are susceptible to environmental erosion. For example, freeze-thaw cycles, sulfate attack, and chloride ion penetration can cause cracking and spalling in their structures, shortening the building's service life while significantly increasing maintenance costs and safety risks. These issues make it difficult to meet the high-performance, long-life, low-maintenance requirements of modern projects.

[0003] To overcome the performance bottlenecks of traditional building materials, researchers have turned their attention to the field of nanomaterials, investigating the application of nanosilica, nanozinc oxide, nanomagnesium oxide, nanoclay, nanotitanium dioxide, and carbon nanotubes in alkali-activated materials. Nanomaterials, with their unique small size effects, surface effects, and quantum size effects, can theoretically significantly improve material performance. However, in practical applications, new problems arise. The introduction of nanomaterials can easily lead to the formation of bubbles within the material. These bubbles severely affect the material's density, leading to the formation of pore defects within the material, reducing its mechanical properties and durability, and decreasing its strength stability.

[0004] At the same time, inorganic materials based on industrial byproducts such as fly ash, silica fume, lithium slag, and slag have attracted considerable attention due to their low cost, widespread availability, and sustainable development. Reusing these industrial byproducts not only effectively alleviates resource shortages and environmental pollution, but also opens up new development directions for the building materials industry. However, these materials currently face numerous challenges in improving their performance: First, insufficient precursor activity. These industrial byproducts themselves have relatively low reactivity, making it difficult to fully react chemically during the alkaline activation process, resulting in slow early strength growth and limited later strength gains. Second, inappropriate polymerization agent formulations—the type, concentration, and ratio of alkaline activators to other additives—fail to provide a suitable reaction environment for the precursors, affecting the material's setting and hardening process and ultimate performance. Third, the material's internal structure lacks density. During the preparation process, factors such as improper particle grading and imperfect molding processes can easily lead to the formation of internal pores and defects, which reduce the material's mechanical properties and durability. Especially when this type of material is used in key parts such as foundation stones, the above-mentioned performance defects will be further amplified, significantly shortening the service life of the building and increasing engineering safety risks.

[0005] Therefore, it is necessary to develop new building materials that have high strength, high structural density and excellent comprehensive performance to promote the development of the construction field. Summary of the Invention

[0006] To address the performance bottlenecks of traditional building materials and meet the urgent demand for high-performance building materials in modern engineering, the present invention provides a high-strength lime-sand polymer building material and its preparation method. By optimizing the precursor combination, polymerization formula, preparation process, and curing conditions, a building material with high strength, high density, and excellent durability is produced. The specific technical solution is as follows:

[0007] A high-strength ash-sand polymer building material, characterized in that it comprises the following raw materials in parts by mass: 40 to 55 parts of calcined fly ash clinker, 15 to 20 parts of silica fume, 10 to 15 parts of lithium slag, 1.5 to 2.5 parts of composite nanofiller, 80 to 90 parts of coal gangue, 1.5 to 3 parts of steel fiber, 35 to 40 parts of polymerization agent, 4 to 6 parts of polymerization auxiliary agent and 1 to 2 parts of defoaming agent.

[0008] Among the above raw materials, the preparation method of calcined fly ash clinker includes: selecting low-calcium fly ash with D50≤5μm and CaO content≤8%, mixing it with 2wt%~3wt% sodium hydroxide aqueous solution at a solid-liquid ratio of (1~1.2):(2~2.5), wet ball milling for 1.5h~2.5h, filtering to remove excess liquid, drying, heating to 600℃~650℃ at a rate of 5℃ / min~6℃ / min and maintaining for 30min~40min to decompose carbonate impurities, then heating to 750℃~850℃ at a rate of 6℃ / min~8℃ / min and maintaining for 2h~2.5h to stimulate the activity of aluminosilicate, and grinding after cooling to a specific surface area of ​​≥600m² / kg.

[0009] Among the above raw materials, the mass ratio of the composite nanofiller is nano-silica: nano-metakaolin: silicon carbide whisker = (2-5): (1-3): (1-1.5); the particle size range of nano-silica is below 100 nm; the particle size range of nano-metakaolin is below 100 nm.

[0010] Among the above raw materials, the preparation method of the polymerization agent includes: compounding a potassium silicate aqueous solution with a modulus of 2.0 to 2.2 and containing 18 wt% to 22 wt% K2O with an 8 mol / L to 12 mol / L potassium hydroxide aqueous solution in a volume ratio of 1: (0.8 to 1), allowing it to stand for 30 minutes to 50 minutes, adjusting the pH to 10 to 11 with citric acid, and allowing it to stand and mature for 12 hours to 18 hours to obtain the polymerization agent.

[0011] Among the above raw materials, the preparation method of the polymerization auxiliary agent includes: adding 2 to 3 times the mass of perfluorohexylethyltriethoxysilane to 85% to 90% volume concentration of ethanol aqueous solution, mixing and hydrolyzing for 30 minutes to 40 minutes, and then adding silane coupling agent KH-560 with an amount of 1% to 3% of the mass of perfluorohexylethyltriethoxysilane, aminobispropyl polydimethylsiloxane with an amount of 3% to 5% of the mass of perfluorohexylethyltriethoxysilane, and diphenylmethane glycidyl ether epoxy resin with an amount of 2 to 3 times the mass of perfluorohexylethyltriethoxysilane, and mixing to obtain the polymerization auxiliary agent.

[0012] Among the above raw materials, the specifications of silica fume are: SiO2 content ≥92wt%, particle size D90 ≤5μm.

[0013] Among the above raw materials, the specifications of lithium slag are: containing 0.8wt%~1.5wt% Li2O, 18wt%~25wt% Al2O3, and particle size D90≤45μm.

[0014] Among the above raw materials, the grading specifications of coal gangue are: particle size range of 10mm~20mm accounts for 40wt%~45wt%, particle size range of 5mm~8mm accounts for 10wt%~15wt%, and particle size range of 0.15mm~4.75mm accounts for 40%~50%.

[0015] Among the above raw materials, the specifications of the steel fiber are: length range 5 to 10 mm, diameter range 0.15 mm to 0.25 mm.

[0016] Among the above raw materials, the defoamer is a polydimethylsiloxane-polyether block copolymer type strong alkali-resistant defoamer, BYK-1790.

[0017] The method for preparing geopolymer stone from the above-mentioned high-strength lime-sand polymer building material comprises the following steps:

[0018] S1: Calcined fly ash clinker, silica fume, and lithium slag are mixed and ground according to mass proportions until D90 ≤ 12 μm to obtain a mixture; the composite nanofiller is ultrasonically dispersed in water, wet-ground with the mixture, and water is added to adjust the slurry viscosity to 3500 cP to 4500 cP to obtain a precursor;

[0019] S2: Mold treatment: clean the mold with a sodium hydroxide aqueous solution with a pH of 10 to 12, then rinse with water, dry, spray with a composite emulsion containing polyvinyl alcohol emulsion and silane coupling agent, and dry to form a coating film of 0.08 mm to 0.15 mm;

[0020] S3: According to the mass proportions, the precursor, polymerization agent and half of the defoaming agent were vacuum stirred at 60 rpm to 80 rpm for 5 min to 10 min, the coal gangue was added in sequence and vacuum stirred at 100 rpm to 120 rpm for 10 min to 15 min, the remaining defoaming agent and polymerization auxiliary agent were added in sequence and vacuum stirred at 100 rpm to 120 rpm for 2 min to 3 min, the steel fiber was added and vacuum stirred at 120 rpm to 140 rpm for 8 min to 10 min to obtain the base material and inject it into the mold;

[0021] S4: The base material injected into the mold is first subjected to low-frequency vibration to promote particle rearrangement, and then subjected to high-frequency pulse vibration and ultrasonic wave synchronous treatment to eliminate pores; it is then subjected to low-temperature curing and molding, and then heated curing after demoulding, and finally cured at room temperature to obtain geopolymer stone.

[0022] In S1 of the above preparation method, the composite nanofiller is added into water with 8 to 10 times its mass, and ultrasonically dispersed for 15 to 20 minutes at a power of 400W to 500W and a frequency of 25kHz to 30kHz; and wet-milled for 40 to 60 minutes.

[0023] In S2 of the above preparation method, in the composite emulsion, the polyvinyl alcohol emulsion with a solid content of 6wt% to 8wt% accounts for 99.7wt% to 99.9wt%, and the silane coupling agent accounts for 0.1wt% to 0.3wt%; the silane coupling agent is KH-550 or KH-560.

[0024] In S3 of the above preparation method, the vacuum degree of vacuum stirring is -0.05 MPa to -0.06 MPa.

[0025] In S4 of the above preparation method, the low frequency vibration is 25Hz~30Hz low frequency vibration for 4min~5min; the high frequency pulse vibration and ultrasonic synchronous treatment are 45Hz~50Hz, 1s~1.5s interval high frequency pulse vibration and 40kHz~45kHz, 500W / m 3 ~600W / m 3 Synchronous ultrasonic assisted treatment for 3min~5min; low temperature curing is to heat up to 40℃~45℃ at a rate lower than 20℃ / h and cure with mold for 12h~14h; heating curing is to heat up to 70℃~80℃ in a steam curing room at a rate lower than 20℃ / h, maintain for 32h~36h, and spray humidification to control the relative humidity ≥90%; normal temperature curing is at normal temperature, spray humidification to control the relative humidity ≥90%, introduce gas containing 25%~30% volume concentration of CO2, monitor the CO2 volume concentration in a closed cycle to be not less than 20%, and cure for 3~4 days.

[0026] The porosity of the geopolymer prepared by the above method is less than 2%; the compressive strength is greater than 120 MPa, and the flexural strength is greater than 18 MPa.

[0027] The geopolymer stone prepared by the above method is used in road surface slabs in weak areas, prefabricated components of super high-rise buildings, corrosion-resistant chemical storage tank linings, and impact-resistant protective works.

[0028] The high-strength lime-sand polymer building material and its preparation method of the present invention have the following beneficial effects:

[0029] 1. The present invention is designed to mix the various components in specific mass fractions, and the raw materials work together to improve the performance of geopolymer. Calcined fly ash clinker, silica fume, and lithium slag provide active ingredients such as silicon and aluminum, laying the foundation for the polymerization reaction. Composite nanofillers can utilize the special effects of nanomaterials to fill pores and enhance interfacial bonding. Coal gangue serves as aggregate to provide support and improve particle grading. Steel fiber enhances toughness and crack resistance. Polymerizers and polymerization adjuvants regulate the reaction process and product structure. Defoamers reduce bubbles and increase density. The raw materials are mixed in this ratio to give the geopolymer high strength, high density, and excellent durability.

[0030] Calcination of fly ash clinker: Through a specific calcination process, the activity of aluminosilicates is stimulated, providing a rich source of active silicon and aluminum for the polymerization reaction, thereby improving the early and later strength of the material. Gangue, as an aggregate, plays a supporting role. Its rational grading optimizes the internal particle packing of the material, improving density, and thereby enhancing mechanical properties and durability. Silica fume, rich in high-purity silica and with a small particle size, can fill the pores of the material and increase density. It also participates in the polymerization reaction, strengthening the silicon-aluminum network structure and enhancing strength and durability. Lithium slag provides active components such as aluminum, participating in the polymerization reaction and helping to form a stable aluminosilicate structure. The presence of lithium slag catalyzes the reaction, thereby improving material performance.

[0031] Third, the polymerization agent is a compound of an aqueous potassium silicate solution and an aqueous potassium hydroxide solution. This provides an alkaline environment, stimulates the activity of the precursors, promotes the dissolution and polymerization of substances such as silicon and aluminum, and rapidly solidifies and hardens the material, improving its early strength. After adjusting the pH with citric acid, the polymerization reaction proceeds under suitable alkaline conditions. This ensures sufficient reaction of the precursors while avoiding excessive alkalinity that could lead to an overly rapid reaction. This facilitates the formation of a uniform and stable silicon-aluminum network structure, improving the material's strength and stability. Furthermore, reducing the strong alkalinity protects the polymerization auxiliary agent from exerting its effectiveness and prevents damage to its molecular structure.

[0032] Fourth, polymeric adjuvants can improve the material's interfacial properties, enhance the bonding between components, and improve the material's workability. This in turn promotes a more uniform distribution of components, especially steel fibers, enhancing the material's overall performance. They also help reduce surface tension and minimize bubble formation. Perfluorohexylethyltriethoxysilane, upon hydrolysis, forms a low-energy layer on the material's surface, lowering surface tension and reducing bubbles. Silane coupling agent KH-560 strengthens the interfacial bonding between the organic and inorganic phases. Aminobispropyl polydimethylsiloxane improves the material's crack and impact resistance. Diphenylmethane glycidyl ether epoxy resin further enhances the material's strength and bonding properties. These components work together to improve material performance in different ways. Furthermore, silane coupling agent KH-560 and aminobispropyl polydimethylsiloxane improve the compatibility between perfluorohexylethyltriethoxysilane and diphenylmethane glycidyl ether epoxy resin.

[0033] 5. In the preparation of geopolymer, the polymerization auxiliary agent is added after the addition of coal gangue and other materials. At this time, the basic structure of the material has been initially formed. The polymerization auxiliary agent can better act on the particle surface and pores, uniformly improving the interface properties and strengthening the bonding strength. If added too early, the polymerization auxiliary agent will react with the polymerization agent (strong base) prematurely during the initial stirring process, and will not be able to play its role in optimizing the interface and strengthening the bonding at the critical stage, thus affecting the material performance.

[0034] 6. This curing method combines multiple curing methods. Low-frequency vibration promotes particle rearrangement, while high-frequency pulse vibration and ultrasound assist in eliminating microscopic voids and improving density. Curing with a mold accelerates polymer formation, while steam curing promotes polycondensation of the silicon-aluminum network. Finally, CO2 carbonization fills remaining voids. Compared to natural curing for 28 days, this method more quickly and effectively improves the material's strength, density, and durability, shortens curing time, improves production efficiency, and allows for more precise control of material properties. DETAILED DESCRIPTION

[0035] The present invention will be further described below with reference to specific implementation cases, but the present invention is not limited to these embodiments.

[0036] Example 1

[0037] A high-strength ash-sand polymer building material comprises the following raw materials in parts by mass: 40 parts of calcined fly ash clinker, 15 parts of silica fume, 10 parts of lithium slag, 1.5 parts of composite nano-filler, 80 parts of coal gangue, 1.5 parts of steel fiber, 35 parts of polymerizing agent, 4 parts of polymerizing auxiliary agent and 1 part of defoaming agent.

[0038] Among them, the preparation method of calcined fly ash clinker includes: selecting low-calcium fly ash with a D50 of 3μm and a CaO content of 6%, mixing it with a 2wt% sodium hydroxide aqueous solution at a solid-liquid ratio of 1:2, wet ball milling for 1.5 hours, filtering to remove excess liquid, drying, heating to 600℃ at a rate of 5℃ / min and maintaining it for 30 minutes to decompose carbonate impurities, then heating to 750℃ at a rate of 6℃ / min and maintaining it for 2 hours to activate the activity of aluminosilicate, and grinding it to a specific surface area of ​​653m² / kg after cooling.

[0039] Among them, the specifications of silica fume are: SiO2 content 94wt%, particle size D90 is 2μm.

[0040] Among them, the specifications of lithium slag are: containing 0.8wt% Li2O, 25wt% Al2O3, and the particle size D90 is 36μm.

[0041] The mass ratio of the composite nano-filler components is nano-silicon dioxide: nano-metakaolin: silicon carbide whisker = 2:1:1; the particle size of the nano-silicon dioxide is less than 100 nm; and the particle size of the nano-metakaolin is less than 100 nm.

[0042] Among them, the grading specifications of coal gangue are: particle size range of 10mm~20mm accounts for 40wt%, particle size range of 5mm~8mm accounts for 15wt%, and particle size range of 0.15mm~4.75mm accounts for 45%.

[0043] Among them, the specifications of steel fiber are: length range 5 to 10 mm, diameter range 0.15 mm to 0.25 mm.

[0044] The preparation method of the polymerizer includes: compounding a potassium silicate aqueous solution with a modulus of 2.0 and containing 18wt% K2O with an 8mol / L potassium hydroxide aqueous solution in a volume ratio of 1:0.8, standing for 30 minutes, adjusting the pH to 10 with citric acid, and standing and maturing for 12 hours to obtain a polymerizer.

[0045] Among them, the preparation method of the polymerization auxiliary agent includes: adding 2 times the mass of perfluorohexylethyltriethoxysilane to 85% volume concentration ethanol aqueous solution, mixing and hydrolyzing for 30 minutes, and then adding silane coupling agent KH-560 with a mass of 1% of perfluorohexylethyltriethoxysilane, aminobispropyl polydimethylsiloxane with a mass of 3% of perfluorohexylethyltriethoxysilane, and diphenylmethane glycidyl ether epoxy resin with a mass of 2 times the mass of perfluorohexylethyltriethoxysilane to obtain the polymerization auxiliary agent.

[0046] Among them, the defoaming agent is a polydimethylsiloxane-polyether block copolymer type strong alkali-resistant defoaming agent, BYK-1790.

[0047] The method for preparing geopolymer stone from the above-mentioned high-strength lime-sand polymer building material comprises the following steps:

[0048] S1: calcined fly ash clinker, silica fume and lithium slag are mixed according to parts by mass and ground to a D90 of 12 μm to obtain a mixture;

[0049] S2: Add the composite nanofiller to 8 times its mass in water, and ultrasonically disperse it at a power of 400 W and a frequency of 25 kHz for 15 minutes to obtain a nanodispersion liquid; wet-grind the mixture and the nanodispersion liquid for 40 minutes, and adjust the slurry viscosity to 3500 cP by adding water to form a precursor;

[0050] S3: The mold is cleaned with a sodium hydroxide aqueous solution having a pH of 10, then washed with water, dried, sprayed with the composite emulsion, and dried into a 0.08 mm coating film;

[0051] In the composite emulsion, polyvinyl alcohol emulsion with a solid content of 6wt% accounts for 99.7wt%, and silane coupling agent accounts for 0.3wt%; the silane coupling agent is KH-550.

[0052] S4: Mix the precursor, polymerization agent and half of the defoamer by mass, stir at 60 rpm under vacuum of -0.05 MPa for 5 min, then add coal gangue, maintain vacuum and stir at 100 rpm for 10 min, then add the remaining defoamer and polymerization auxiliary agent in sequence, maintain vacuum and stir at 100 rpm for 2 min, finally add steel fiber, maintain vacuum and stir at 120 rpm for 8 min to obtain the base material, which is then injected into the mold;

[0053] S5: The base material injected into the mold is first subjected to 25Hz low-frequency vibration for 4 minutes to promote particle rearrangement, and then subjected to 45Hz high-frequency pulse vibration with an interval of 1s and 40kHz, 500W / m 3 Synchronous ultrasonic assisted treatment for 3 minutes to eliminate microscopic pores; the temperature was raised to 40°C at a rate of 15°C / h and cured in a mold for 12 hours to accelerate polymer molding; after demolding, the temperature was raised to 70°C at a rate of 15°C / h in a steam curing chamber and maintained for 32 hours, and spray humidification was used to control the relative humidity to fluctuate between 90% and 95% to further promote the condensation of the silicon-aluminum network; then, at room temperature, spray humidification was used to control the relative humidity to fluctuate between 90% and 95%, and a gas containing 25% volume concentration of CO2 was introduced, and the CO2 volume concentration was monitored in a closed cycle to fluctuate between 20% and 25%. After curing for 3 days, the remaining pores were filled with CO2 carbonization to obtain geopolymer stone.

[0054] Example 2

[0055] A high-strength ash-sand polymer building material comprises the following raw materials in parts by mass: 48 parts of calcined fly ash clinker, 18 parts of silica fume, 12 parts of lithium slag, 2 parts of composite nano-filler, 85 parts of coal gangue, 2 parts of steel fiber, 38 parts of polymerizing agent, 5 parts of polymerizing auxiliary agent and 1.5 parts of defoaming agent.

[0056] Among them, the preparation method of calcined fly ash clinker includes: selecting low-calcium fly ash with a D50 of 4μm and a CaO content of 7%, mixing it with a 2.5wt% sodium hydroxide aqueous solution at a solid-liquid ratio of 1.1:2.3, wet ball milling for 2h, filtering to remove excess liquid, drying, heating to 630℃ at a rate of 5℃ / min and holding for 35min to decompose carbonate impurities, then heating to 800℃ at a rate of 7℃ / min and holding for 2h to activate the activity of aluminosilicate, and grinding to a specific surface area of ​​627m² / kg after cooling.

[0057] Among them, the specifications of silica fume are: SiO2 content 93wt%, particle size D90 is 5μm.

[0058] Among them, the specifications of lithium slag are: containing 1wt% Li2O, 18wt% Al2O3, and the particle size D90 is 42μm.

[0059] The mass ratio of the composite nano-filler components is nano-silicon dioxide: nano-metakaolin: silicon carbide whisker = 3:2:1.2; the particle size of the nano-silicon dioxide is less than 100 nm; and the particle size of the nano-metakaolin is less than 100 nm.

[0060] Among them, the grading specifications of coal gangue are: particle size range of 10mm~20mm accounts for 40wt%, particle size range of 5mm~8mm accounts for 10wt%, and particle size range of 0.15mm~4.75mm accounts for 50%.

[0061] Among them, the specifications of steel fiber are: length range 5 to 10 mm, diameter range 0.15 mm to 0.25 mm.

[0062] Among them, the preparation method of the polymerizer includes: compounding a potassium silicate aqueous solution with a modulus of 2.1 and containing 20wt% K2O with a 10mol / L potassium hydroxide aqueous solution in a volume ratio of 1:0.9, standing for 40 minutes, adjusting the pH to 10.5 with citric acid, and standing and aging for 15 hours to obtain a polymerizer.

[0063] Among them, the preparation method of the polymerization auxiliary agent includes: adding 2.5 times the mass of perfluorohexylethyltriethoxysilane to 87% volume concentration ethanol aqueous solution, mixing and hydrolyzing for 35 minutes, and then adding silane coupling agent KH-560 with a mass of 2% of perfluorohexylethyltriethoxysilane, aminobispropyl polydimethylsiloxane with a mass of 4% of perfluorohexylethyltriethoxysilane, and diphenylmethane glycidyl ether epoxy resin with a mass of 2.5 times that of perfluorohexylethyltriethoxysilane to obtain the polymerization auxiliary agent.

[0064] Among them, the defoaming agent is a polydimethylsiloxane-polyether block copolymer type strong alkali-resistant defoaming agent, BYK-1790.

[0065] The method for preparing geopolymer stone from the above-mentioned high-strength lime-sand polymer building material comprises the following steps:

[0066] S1: calcined fly ash clinker, silica fume and lithium slag are mixed according to parts by mass and ground to a D90 of 8 μm to obtain a mixture;

[0067] S2: Add the composite nanofiller to 9 times its mass in water, and ultrasonically disperse it at a power of 450 W and a frequency of 28 kHz for 18 minutes to obtain a nanodispersion liquid. Wet-grind the mixture and the nanodispersion liquid for 50 minutes, and adjust the slurry viscosity to 4000 cP by adding water to form a precursor.

[0068] S3: The mold is cleaned with a sodium hydroxide aqueous solution of pH 11, then washed with water, dried, sprayed with the composite emulsion, and dried into a 0.1 mm coating film;

[0069] In the composite emulsion, polyvinyl alcohol emulsion with a solid content of 7wt% accounts for 99.9wt%, and silane coupling agent accounts for 0.1wt%; the silane coupling agent is KH-560.

[0070] S4: Mix the precursor, polymerization agent and half of the defoamer by mass, stir at 70 rpm under vacuum of -0.06 MPa for 8 min, then add coal gangue, maintain vacuum and stir at 110 rpm for 12 min, then add the remaining defoamer and polymerization auxiliary agent in sequence, maintain vacuum and stir at 110 rpm for 2 min, finally add steel fiber, maintain vacuum and stir at 130 rpm for 9 min to obtain the base material, which is then injected into the mold;

[0071] S5: The base material injected into the mold is first subjected to 28Hz low-frequency vibration for 4 minutes to promote particle rearrangement, and then subjected to 48Hz, 1.2s interval high-frequency pulse vibration and 42kHz, 550W / m 3 Synchronous ultrasonic assisted treatment for 4 minutes to eliminate microscopic pores; the temperature was raised to 42°C at a rate of 18°C / h and cured in a mold for 13 hours to accelerate polymer molding; after demolding, the temperature was raised to 75°C at a rate of 18°C / h in a steam curing chamber and maintained for 34 hours, and spray humidification was used to control the relative humidity to fluctuate between 90% and 95% to further promote the condensation of the silicon-aluminum network; then, at room temperature, spray humidification was used to control the relative humidity to fluctuate between 90% and 95%, and a gas containing 28% volume concentration of CO2 was introduced, and the CO2 volume concentration was monitored in a closed cycle at 24% to 28% fluctuations. After curing for 3 days, the remaining pores were filled with CO2 carbonization to obtain geopolymer stone.

[0072] Example 3

[0073] A high-strength ash-sand polymer building material comprises the following raw materials in parts by mass: 55 parts of calcined fly ash clinker, 20 parts of silica fume, 15 parts of lithium slag, 2.5 parts of composite nano-filler, 90 parts of coal gangue, 3 parts of steel fiber, 40 parts of polymerizing agent, 6 parts of polymerizing auxiliary agent and 2 parts of defoaming agent.

[0074] Among them, the preparation method of calcined fly ash clinker includes: selecting low-calcium fly ash with a D50 of 5μm and a CaO content of 8%, mixing it with a 3wt% sodium hydroxide aqueous solution at a solid-liquid ratio of 1.2:2.5, wet ball milling for 2.5 hours, filtering to remove excess liquid, drying, heating to 650℃ at a rate of 6℃ / min and maintaining it for 40 minutes to decompose carbonate impurities, then heating to 850℃ at a rate of 8℃ / min and maintaining it for 2.5 hours to activate the activity of aluminosilicate, and grinding it to a specific surface area of ​​600m² / kg after cooling.

[0075] Among them, the specifications of silica fume are: SiO2 content 92wt%, particle size D90 is 4μm.

[0076] Among them, the specifications of lithium slag are: containing 1.5wt% Li2O, 21wt% Al2O3, and the particle size D90 is 45μm.

[0077] The mass ratio of the composite nanofiller is nano-silicon dioxide: nano-metakaolin: silicon carbide whisker = 5:3:1.5; the particle size of the nano-silicon dioxide is less than 100 nm; the particle size of the nano-metakaolin is less than 100 nm.

[0078] Among them, the grading specifications of coal gangue are: particle size range of 10mm~20mm accounts for 45wt%, particle size range of 5mm~8mm accounts for 15wt%, and particle size range of 0.15mm~4.75mm accounts for 40%.

[0079] Among them, the specifications of steel fiber are: length range 5 to 10 mm, diameter range 0.15 mm to 0.25 mm.

[0080] Among them, the preparation method of the polymerizer includes: compounding a potassium silicate aqueous solution with a modulus of 2.2 and containing 22wt% K2O with a 12mol / L potassium hydroxide aqueous solution in a volume ratio of 1:1, standing for 50 minutes, adjusting the pH to 11 with citric acid, and standing and maturing for 18 hours to obtain a polymerizer.

[0081] Among them, the preparation method of the polymerization auxiliary agent includes: adding 3 times the mass of perfluorohexylethyltriethoxysilane to a 90% volume concentration ethanol aqueous solution, mixing and hydrolyzing for 40 minutes, and then adding silane coupling agent KH-560 with a mass of 3% of the mass of perfluorohexylethyltriethoxysilane, aminobispropyl polydimethylsiloxane with a mass of 5% of the mass of perfluorohexylethyltriethoxysilane, and diphenylmethane glycidyl ether epoxy resin with a mass of 3 times the mass of perfluorohexylethyltriethoxysilane, and mixing to obtain the polymerization auxiliary agent.

[0082] Among them, the defoaming agent is a polydimethylsiloxane-polyether block copolymer type strong alkali-resistant defoaming agent, BYK-1790.

[0083] The method for preparing geopolymer stone from the above-mentioned high-strength lime-sand polymer building material comprises the following steps:

[0084] S1: calcined fly ash clinker, silica fume and lithium slag are mixed according to parts by mass, and ground to a D90 of 10 μm to obtain a mixture;

[0085] S2: Add the composite nanofiller to 10 times its mass in water, and ultrasonically disperse it at a power of 500 W and a frequency of 30 kHz for 20 minutes to obtain a nanodispersion liquid; wet-grind the mixture and the nanodispersion liquid for 60 minutes, and adjust the slurry viscosity to 4500 cP by adding water to form a precursor;

[0086] S3: The mold is cleaned with a sodium hydroxide aqueous solution with a pH of 12, then washed with water, dried, sprayed with the composite emulsion, and dried into a 0.15 mm coating film;

[0087] In the composite emulsion, polyvinyl alcohol emulsion with a solid content of 8wt% accounts for 99.8wt%, and silane coupling agent accounts for 0.2wt%; the silane coupling agent is KH-560.

[0088] S4: Mix the precursor, polymerization agent and half of the defoamer by mass, stir at 80 rpm under vacuum of -0.06 MPa for 10 min, then add coal gangue, maintain vacuum and stir at 120 rpm for 15 min, then add the remaining defoamer and polymerization auxiliary agent in sequence, maintain vacuum and stir at 120 rpm for 3 min, finally add steel fiber, maintain vacuum and stir at 140 rpm for 10 min to obtain the base material, which is then injected into the mold;

[0089] S5: The base material injected into the mold is first subjected to 30Hz low-frequency vibration for 5 minutes to promote particle rearrangement, and then subjected to 50Hz, 1.5s interval high-frequency pulse vibration and 45kHz, 600W / m 3 Synchronous ultrasonic assisted treatment for 5 minutes to eliminate microscopic pores; the temperature was raised to 45°C at a rate of 20°C / h and cured in a mold for 14 hours to accelerate polymer molding; after demolding, the temperature was raised to 80°C at a rate of 20°C / h in a steam curing chamber and maintained for 36 hours, and spray humidification was used to control the relative humidity to fluctuate between 90% and 95% to further promote the condensation of the silicon-aluminum network; then, at room temperature, spray humidification was used to control the relative humidity to fluctuate between 90% and 95%, and a gas containing 30% volume concentration of CO2 was introduced, and the CO2 volume concentration was monitored in a closed cycle at 25% to 30% fluctuations. After curing for 4 days, the remaining pores were filled with CO2 carbonization to obtain geopolymer stone.

[0090] Sources of raw materials in the above examples are as follows: fly ash was sourced from Shijiazhuang Xuhan New Materials Technology Co., Ltd.; silica fume was sourced from Lingshou County Jinyuan Mining Processing Plant; lithium slag was sourced from China Construction Western Construction New Materials Technology Co., Ltd.; nanosilica was sourced from Shanghai Huijingya Nano New Materials Co., Ltd.; nanometakaolin was sourced from Foshan Hongsheng Powder Technology Co., Ltd.; calcined kaolin was sourced from Shanghai Naio Nano Technology Co., Ltd.; coal gangue was sourced from Lingshou County Cailin Mineral Products Processing Plant; perfluorohexylethyltriethoxysilane was sourced from Shanghai Fuzhe Chemical Co., Ltd.; diphenylmethane glycidyl ether epoxy resin was sourced from Huizhou Sanhua Electronic Insulation Materials Co., Ltd.; AG-80 tetrafunctional epoxy resin was sourced from Huizhou Sanhua Electronic Insulation Materials Co., Ltd.; polyvinyl alcohol (model 17-88) was sourced from Langfang Longteng New Materials Co., Ltd.; polyvinyl alcohol was dissolved in water to prepare a polyvinyl alcohol emulsion. Silane coupling agents KH-550 and KH-560 were sourced from Henan Wanshan New Materials Technology Co., Ltd.

[0091] Comparative Example 1

[0092] The material (geopolymer stone) contains 80 parts of calcined fly ash clinker and 40 parts of coal gangue; other parameters and methods are the same as those in Example 1.

[0093] Comparative Example 2

[0094] The material (geopolymer stone) contains 30 parts of silica fume and 5 parts of lithium slag; other parameters and methods are the same as those in Example 1.

[0095] Comparative Example 3

[0096] The material (geopolymer stone) contains 20 parts of polymerizing agent; other parameters and methods are the same as those in Example 1.

[0097] Comparative Example 4

[0098] In the material (geopolymer stone), the polymerizing agent was prepared without using citric acid to adjust the pH; other parameters and methods were the same as in Example 1.

[0099] Comparative Example 5

[0100] No polymerization auxiliary agent was added to the material (geopolymer stone); other parameters and methods were the same as those in Example 1.

[0101] Comparative Example 6

[0102] The material (geopolymer stone) contains 2 parts of polymerization auxiliary agent; other parameters and methods are the same as those in Example 1.

[0103] Comparative Example 7

[0104] No silane coupling agent KH-560 was added to the polymerization auxiliary agent; other parameters and methods were the same as in Example 1.

[0105] Comparative Example 8

[0106] No aminobispropyl polydimethylsiloxane was added to the polymerization auxiliary agent; other parameters and methods were the same as in Example 1.

[0107] Comparative Example 9

[0108] No diphenylmethane glycidyl ether epoxy resin was added to the polymerization auxiliary agent; other parameters and methods were the same as in Example 1.

[0109] Comparative Example 10

[0110] In the geopolymer preparation method S4, the polymerization auxiliary agent is not added after the coal gangue, but is added in advance together with the polymerization agent; other parameters and methods are the same as in Example 1.

[0111] Comparative Example 11

[0112] In the geopolymer preparation method S5, the curing method is as follows: temperature 25° C., relative humidity fluctuation 90% to 95%, and natural curing for 28 days; other parameters and methods are the same as in Example 1.

[0113] According to the formula and method of each embodiment and comparative example, a number of 100mm×100mm×100mm geopolymer samples were prepared for compressive strength, chloride ion penetration rate, porosity, 90d sulfate erosion resistance strength loss rate, and 300 freeze-thaw cycle mass loss rate tests; a number of 40mm×40mm×160mm geopolymer samples were prepared for flexural strength, carbonization resistance, and wear resistance tests.

[0114] 1. Compressive Strength: Test according to GB / T 50081, "Standard for Test Methods of Mechanical Properties of Ordinary Concrete." Place the specimen in a compression testing machine and apply a load until the specimen fails. Record the failure load and calculate the compressive strength.

[0115] 2. Flexural Strength: Test according to GB / T 50081, "Standard for Test Methods of Mechanical Properties of Ordinary Concrete." Specimens were subjected to flexural testing using a three-point loading method at a loading rate of 0.02 MPa per second. The load at failure was recorded and the flexural strength was calculated.

[0116] 3. Chloride Ion Permeation Rate: This test is conducted using the electrical flux method, in accordance with GB / T 50082, "Standard for Test Methods for Long-Term Performance and Durability of Ordinary Concrete." The specimen is cut into 50 mm thick discs, saturated with water under vacuum, and placed in a DC coulometer. A current is applied at a constant voltage of 60 V DC for 6 hours, and the electrical flux through the specimen is measured to evaluate the chloride ion permeation rate.

[0117] 4. Porosity: Using the mercury intrusion method, the sample is broken into small pieces of 1mm-5mm, dried to constant weight, and placed in a mercury intrusion instrument. The porosity of the material is calculated by measuring the volume of mercury entering the pores of the material under pressure.

[0118] 5. 90d sulfate erosion resistance strength loss rate: Soak the sample in 5wt% sodium sulfate solution for 90 days. After taking it out, wipe off the surface moisture and measure its strength according to the compressive strength test method. Calculate the strength loss rate by comparing it with the compressive strength before soaking.

[0119] 6. Mass loss after 300 freeze-thaw cycles: Test according to GB / T 50082, "Test Methods for Long-term Properties and Durability of Ordinary Concrete." Place the specimen in a freeze-thaw testing machine and subject it to freeze-thaw cycles between -20°C and 5°C, with each cycle lasting 4 hours. After 300 cycles, measure the specimen mass and calculate the mass loss.

[0120] 7. Carbonation resistance: Test according to GB / T50082, "Test Methods for Long-term Performance and Durability of Ordinary Concrete." Place the specimen in a carbonation chamber with a controlled carbon dioxide concentration of (20±3)%, relative humidity of (70±5)%, and temperature of (20±2)°C. After 28 days of carbonation, use phenolphthalein as an indicator to measure the depth of carbonation and assess carbonation resistance.

[0121] 8. Abrasion resistance: Refer to GB / T 12988, Test method for wear resistance of inorganic floor materials. Use a rotary abrader after weighing, 500g load, 1000 revolutions, weigh and calculate the wear mass.

[0122] In the above test, three parallel samples were prepared for each sample, and the test result interval values ​​are as follows.

[0123] Table 1 Test results

[0124]

[0125] Examples 1 to 3 form a dense silicon-aluminum network structure inside the material by reasonably proportioning raw materials such as calcined fly ash clinker, silica fume, lithium slag, and improving the internal structure with composite nanofillers, and the synergistic effect of the polymerizer and the polymerization auxiliary agent, combined with specific preparation technology and curing conditions, thereby having better mechanical properties and durability.

[0126] In Comparative Example 1, the amount of fly ash clinker (80 parts) was excessive, while the amount of gangue (40 parts) was insufficient. The excessive fly ash resulted in the accumulation of unreacted particles, while the insufficient aggregate (gangue) weakened the skeleton support, increasing porosity. The interconnected pores allowed water intrusion, exacerbating frost heave stress and significantly degrading mechanical properties.

[0127] In Comparative Example 2, the amount of silica fume (30 parts) was excessive, while the amount of lithium slag (5 parts) was insufficient. The excess silica fume caused agglomeration, while the insufficient lithium slag weakened the accelerating coagulant effect, resulting in an uneven gel structure. The unbalanced particle size distribution created permeable channels, impairing the internal uniformity of the material and affecting its stability and integrity. This resulted in stress concentration under load, resulting in a decrease in mechanical properties. The uneven structure also reduced the material's impermeability and durability.

[0128] In Comparative Example 3, the amount of polymerization agent (20 parts) was insufficient, failing to provide a sufficient alkaline environment and driving force for the precursor reaction. Consequently, the base-activated reaction was incomplete, resulting in insufficient amounts of silica-alumina polymerized products, making it difficult to effectively fill pores and bond particles. Consequently, the material's density decreased, weakening its mechanical properties. The loose structure also resulted in poor impermeability, increased susceptibility to damage in corrosive environments, and reduced durability.

[0129] In Comparative Example 4, the pH of the polymerization agent was not adjusted, resulting in an alkalinity that was unsuitable for the precursor reaction. Furthermore, the strong base more easily destroyed the component structure of the polymerization auxiliary, reducing the auxiliary's efficacy. Excessively strong or weak alkalinity can affect the reaction rate and product structure, resulting in suboptimal silicon-aluminum polymerization, reduced polymerization auxiliary efficacy, and decreased mechanical properties and durability.

[0130] The polymeric adjuvant in Comparative Example 5 enhances inter-particle bonding, improves material surface properties, enhances component workability, and improves uniform distribution of components. Without the polymeric adjuvant, the bonding between particles within the material is weakened, causing particles to slide relative to each other under stress, resulting in reduced mechanical properties. Poor workability also affects the distribution of steel fibers. Furthermore, surface properties deteriorate, reducing the material's impermeability and erosion resistance, and impacting durability.

[0131] In Comparative Example 6, the amount of polymerization adjuvant used was insufficient, failing to fully realize its role in optimizing the particle interface, enhancing bonding, improving component workability, enhancing uniform distribution of ingredients, and improving material properties. The internal structure of the material was not sufficiently optimized, and while some improvement was still achieved, the improvement in mechanical properties and durability was smaller than that achieved with an appropriate dosage.

[0132] The silane coupling agent KH-560 in Comparative Example 7 effectively enhances the bonding between different components and improves the compatibility of the polymerization auxiliary components, thereby effectively exerting the polymerization auxiliary's effect on other materials. Without this component, the internal components of the polymerization auxiliary have poor compatibility. After its addition, the interfacial adhesion between the inorganic raw materials and other additives in the material decreases, resulting in weak bonding between particles and prone to interfacial failure under stress and erosion. Poor workability also affects the distribution of steel fibers, leading to reduced mechanical properties and durability.

[0133] Comparative Example 8: Aminobispropyl polydimethylsiloxane improves the material's crack resistance and enhances the compatibility of the polymerization auxiliary components. Without this component, the internal components of the polymerization auxiliary have poor compatibility. Its addition reduces the interfacial adhesion between the inorganic raw materials and other additives in the material. The workability of the particle components affects the distribution of steel fibers, preventing effective stress dispersion and easily causing microcracks. This reduces the material's mechanical properties and provides a path for corrosive media, weakening its durability.

[0134] Comparative Example 9: Diphenylmethane glycidyl ether epoxy resin enhances the material's bond strength and hardness. Without this component, the material suffers from insufficient bond strength between particles, reduced overall hardness, and prone to plastic deformation under stress, resulting in reduced mechanical properties. Furthermore, the surface's wear resistance and erosion resistance deteriorate, impacting durability.

[0135] In Comparative Example 10, the premature addition of the polymerization auxiliary caused it to interact with the polymerization agent too early in the initial reaction. The continued action of the strong base in the polymerization agent prematurely destroyed the molecular structure, reducing the polymerization auxiliary's effect on the inorganic components. Consequently, the auxiliary failed to fully optimize the particle interface, promote uniform dispersion, and enhance adhesion in subsequent processes. Consequently, the internal structure of the material was not effectively improved, resulting in suboptimal performance.

[0136] The natural curing conditions in Comparative Example 11 differ significantly from those in the Examples. Lacking processes such as heating to accelerate polymerization, steam curing to promote polycondensation of the silicon-aluminum network, and CO2 carbonization to fill pores, the material reaction is slow and incomplete, resulting in a loose internal structure and high porosity. Consequently, the mechanical properties, impermeability, and durability of the material are inferior to those of the Examples.

Claims

1. A high-strength lime-sand polymer building material, characterized in that: The invention comprises the following raw materials in parts by weight: 40 to 55 parts of calcined fly ash clinker, 15 to 20 parts of silica fume, 10 to 15 parts of lithium slag, 1.5 to 2.5 parts of composite nano-filler, 80 to 90 parts of coal gangue, 1.5 to 3 parts of steel fiber, 35 to 40 parts of polymerization agent, 4 to 6 parts of polymerization auxiliary agent and 1 to 2 parts of defoaming agent; The composite nano-filler comprises nano-silicon dioxide, nano-metakaolin and silicon carbide whiskers; The polymerization agent is prepared by mixing potassium silicate aqueous solution and potassium hydroxide aqueous solution in a volume ratio of 1: (0.8-1), adjusting the pH to 10-11 with citric acid after standing, and standing and aging. The polymerization auxiliary agent is prepared by hydrolyzing perfluorohexylethyltriethoxysilane with an ethanol aqueous solution, and then adding a silane coupling agent KH-560, aminobispropyl polydimethylsiloxane and diphenylmethane glycidyl ether epoxy resin and mixing them.

2. A high-strength lime-sand polymer building material according to claim 1, characterized in that: The preparation method of calcined fly ash clinker includes: selecting low-calcium fly ash with D50≤5μm and CaO content≤8%, mixing it with 2wt%~3wt% sodium hydroxide aqueous solution at a solid-liquid ratio of (1~1.2):(2~2.5), wet ball milling for 1.5h~2.5h, filtering to remove excess liquid, drying, heating to 600℃~650℃ at a rate of 5℃ / min~6℃ / min and maintaining for 30min~40min to decompose carbonate impurities, then heating to 750℃~850℃ at a rate of 6℃ / min~8℃ / min and maintaining for 2h~2.5h to stimulate the activity of aluminosilicate, and grinding to a specific surface area of ​​≥600m² / kg after cooling.

3. The high-strength lime-sand polymer building material according to claim 1, characterized in that: The mass ratio of the components of the composite nanofiller is nano-silica: nano-metakaolin: silicon carbide whisker = (2-5): (1-3): (1-1.5); the particle size range of the nano-silica is below 100 nm; the particle size range of the nano-metakaolin is below 100 nm.

4. The high-strength lime-sand polymer building material according to claim 1, characterized in that: The preparation method of the polymerizer includes: compounding a potassium silicate aqueous solution with a modulus of 2.0 to 2.2 and containing 18 wt% to 22 wt% of K2O and an 8 mol / L to 12 mol / L potassium hydroxide aqueous solution in a volume ratio of 1: (0.8 to 1), standing for 30 minutes to 50 minutes, adjusting the pH to 10 to 11 with citric acid, and standing and maturing for 12 hours to 18 hours to obtain the polymerizer.

5. The high-strength lime-sand polymer building material according to claim 1, characterized in that: The preparation method of the polymerization auxiliary agent includes: adding 2 to 3 times the mass of perfluorohexylethyltriethoxysilane to an 85% to 90% volume concentration ethanol aqueous solution, mixing and hydrolyzing for 30 to 40 minutes, then adding 1% to 3% of the mass of the perfluorohexylethyltriethoxysilane as a silane coupling agent KH-560, 3% to 5% of the mass of the perfluorohexylethyltriethoxysilane as aminobispropyl polydimethylsiloxane, and 2 to 3 times the mass of the perfluorohexylethyltriethoxysilane as diphenylmethane glycidyl ether epoxy resin, and mixing to obtain the polymerization auxiliary agent.

6. The high-strength lime-sand polymer building material according to claim 1, characterized in that: Specifications of silica fume: SiO2 content ≥92wt%, particle size D90 ≤5μm; specifications of lithium slag: containing 0.8wt%~1.5wt% Li2O, 18wt%~25wt% Al2O3, particle size D90 ≤45μm; grading specifications of coal gangue: particle size range of 10mm~20mm accounts for 40wt%~45wt%, particle size range of 5mm~8mm accounts for 10wt%~15wt%, particle size range of 0.15mm~4.75mm accounts for 40%~50%; specifications of steel fiber: length range of 5~10mm, diameter range of 0.15mm~0.25mm; defoaming agent is BYK-1790.

7. A method for preparing geopolymer stone, using the high-strength lime-sand polymer building material according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: S1: Calcined fly ash clinker, silica fume, and lithium slag are mixed and ground according to mass proportions until D90 ≤ 12 μm to obtain a mixture; the composite nanofiller is ultrasonically dispersed in water, wet-ground with the mixture, and water is added to adjust the slurry viscosity to 3500 cP to 4500 cP to obtain a precursor; S2: Mold treatment: clean the mold with a sodium hydroxide aqueous solution with a pH of 10 to 12, rinse with water, dry, spray with a composite emulsion containing polyvinyl alcohol emulsion and silane coupling agent, and dry to form a coating film of 0.08 mm to 0.15 mm; S3: According to the mass proportions, the precursor, polymerization agent and half of the defoaming agent were vacuum stirred at 60 rpm to 80 rpm for 5 min to 10 min, the coal gangue was added in sequence and vacuum stirred at 100 rpm to 120 rpm for 10 min to 15 min, the remaining defoaming agent and polymerization auxiliary agent were added in sequence and vacuum stirred at 100 rpm to 120 rpm for 2 min to 3 min, the steel fiber was added and vacuum stirred at 120 rpm to 140 rpm for 8 min to 10 min to obtain the base material and inject it into the mold; S4: The base material injected into the mold is first subjected to low-frequency vibration to promote particle rearrangement, and then subjected to high-frequency pulse vibration and ultrasonic wave synchronous treatment to eliminate pores; it is then subjected to low-temperature curing and molding, and then heated curing after demoulding, and finally cured at room temperature to obtain geopolymer stone.

8. The method for preparing geopolymer stone according to claim 7, characterized in that: In S1, the composite nanofiller is added to 8 to 10 times the mass of water, and ultrasonic dispersion is carried out for 15 to 20 minutes at a power of 400 W to 500 W and a frequency of 25 kHz to 30 kHz; wet grinding is carried out for 40 to 60 minutes; in S2, in the composite emulsion, the polyvinyl alcohol emulsion with a solid content of 6 wt% to 8 wt% accounts for 99.7 wt% to 99.9 wt%, and the silane coupling agent accounts for 0.1 wt% to 0.3 wt%; the silane coupling agent is KH-550 or KH-560; in S3, the vacuum degree of vacuum stirring is -0.05 MPa to -0.06 MPa.

9. The method for preparing geopolymer stone according to claim 7, characterized in that: In S4, low-frequency vibration is 25Hz~30Hz low-frequency vibration for 4min~5min; high-frequency pulse vibration and ultrasonic synchronous treatment are 45Hz~50Hz, interval 1s~1.5s high-frequency pulse vibration and 40kHz~45kHz, 500W / m 3 ~600W / m 3 Synchronous ultrasonic assisted treatment for 3min~5min; low temperature curing is to heat up to 40℃~45℃ at a rate lower than 20℃ / h and cure with mold for 12h~14h; heating curing is to heat up to 70℃~80℃ in a steam curing room at a rate lower than 20℃ / h, maintain for 32h~36h, and spray humidification to control the relative humidity ≥90%; normal temperature curing is at normal temperature, spray humidification to control the relative humidity ≥90%, introduce gas containing 25%~30% volume concentration of CO2, monitor the CO2 volume concentration in a closed cycle to be not less than 20%, and cure for 3~4 days.

10. The method for preparing geopolymer stone according to claim 7, characterized in that: In S4, the porosity of the geopolymer is less than 2%; the compressive strength is greater than 120 MPa, and the flexural strength is greater than 18 MPa.

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