Industrial and agricultural solid waste-based carbon-sequestration thermal-insulation high-strength geopolymer material and preparation method thereof

Abstract

The invention discloses a carbon-sequestration heat-preservation high-strength geopolymer material based on industrial and agricultural solid waste and a preparation method of the carbon-sequestration heat-preservation high-strength geopolymer material, and belongs to the technical field of building material preparation. The carbon-sequestration heat-preservation high-strength geopolymer material based on the industrial and agricultural solid waste comprises 20%-50% of biomass power generation ash, 1%-15% of straw powder, 10%-20% of iron tailing sand and the balance steel slag powder. The biomass power generation ash and the steel slag powder are used as precursors, the straw powder and the iron tailing sand are used as fillers, potassium hydroxide and potassium silicate are mixed to serve as alkali activators, the light high-strength material is prepared, on the premise that the strength is guaranteed, the preparation cost of geopolymers is successfully reduced, the heat preservation performance of the material is improved, and meanwhile, the material has the good application prospect. And carbon emission in preparation of the geopolymer thermal insulation material is further reduced through a carbonization curing mode.

Description

Technical Field

[0001] This invention belongs to the field of building material preparation technology, specifically relating to a high-strength geopolymer material for carbon sequestration and insulation based on industrial and agricultural solid waste and its preparation method. Background Technology

[0002] The construction industry faces severe challenges due to high carbon emissions in concrete production, urgently requiring innovative low-carbon solutions. Meanwhile, traditional methods of treating agricultural waste (such as straw and rice husks) in my country pose environmental risks. Using these wastes as cement admixtures in concrete can achieve both resource utilization and contribute to emission reduction in the industry, thus possessing both environmental and economic value.

[0003] Existing studies have confirmed that agricultural solid wastes such as rice husk powder and straw powder, as active admixtures, can replace part of the cement and have significant potential for energy conservation and emission reduction. Meanwhile, numerous experiments and engineering practices have shown that the incorporation of agricultural solid wastes also has a positive impact on the mechanical properties, durability, and thermal insulation of concrete, thus improving the overall performance of concrete to a certain extent.

[0004] However, current research still has significant limitations. Patent searches reveal that while existing technologies have made progress in specific performance aspects, none have achieved synergistic optimization of engineering and environmental performance. Specifically:

[0005] Invention patent CN118459194A utilizes the structural characteristics of rice husk ash to significantly improve the interlayer adhesion, yield strength, thixotropy, and constructability of the material, but it does not demonstrate significant advantages in thermal insulation and strength. Invention patent CN119330617A, a composite cementitious material prepared from biomass power plant ash and blast furnace slag, possesses a porous structure and good thermal insulation, but its mechanical properties and low-carbon characteristics are not fully realized. Invention patent CN115403284B proposes an alkali-activated cementitious material that effectively inhibits efflorescence and exhibits high strength, rapid setting, high fluidity, and durability, but its low-carbon characteristics and thermal insulation performance are still insufficient. Therefore, existing technologies either focus on improving a single performance aspect or suffer from an imbalance in overall performance, making it difficult to meet the current societal demand for composite materials that combine excellent engineering and environmental performance. Thus, developing a high-performance material with synergistically optimized performance has become a crucial issue that urgently needs to be addressed.

[0006] In conclusion, industrial and agricultural solid waste has significant practical implications and broad development prospects. Optimizing the proportions of agricultural solid wastes such as rice husk powder and straw powder as active admixtures to replace a portion of cement, while ensuring energy conservation and emission reduction during concrete production, can improve the mechanical properties of concrete. Realizing its application value through low carbon emissions and significantly enhanced mechanical properties has become a new research topic. Therefore, achieving carbon fortification of geopolymer concrete through optimizing the mix proportions of industrial and agricultural solid waste admixtures has become a new technical problem to be solved. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention discloses a high-strength geopolymer material for carbon fixation and thermal insulation based on industrial and agricultural solid waste, and its preparation method.

[0008] The first aspect of this invention discloses a carbon-fixing, heat-insulating, high-strength geopolymer material based on industrial and agricultural solid waste. The carbon-fixing, heat-insulating, high-strength geopolymer material based on industrial and agricultural solid waste comprises: 20% to 50% biomass power generation ash, 1% to 15% straw powder, 10% to 20% iron tailings sand, and the balance being steel slag powder.

[0009] As an improvement to the present invention, the carbon-fixing and heat-insulating high-strength geopolymer material based on industrial and agricultural solid waste comprises, with a mass of 100%, 25% to 30% biomass power generation ash, 3% to 13% straw powder, 10% to 15% iron tailings sand, and the remainder being steel slag powder.

[0010] As a further improvement of the present invention, based on 100% of the mass of industrial and agricultural solid waste admixture, the carbon-fixing and heat-insulating high-strength geopolymer material based on industrial and agricultural solid waste includes: 25% biomass power generation ash, 5% to 10% straw powder, 10% to 15% iron tailings sand, and 45% to 55% steel slag powder.

[0011] As an improvement of the present invention, the carbon-fixing and heat-insulating high-strength geopolymer material based on industrial and agricultural solid waste further includes an alkali activator, the amount of which is 4% to 8% of the alkali equivalent.

[0012] As a preferred embodiment of the present invention, the alkaline activator comprises potassium silicate and potassium hydroxide; the modulus of the alkaline activator is 1.0 to 1.5.

[0013] As a preferred embodiment of the present invention, the particle size of the steel slag powder is less than 100 micrometers.

[0014] The second aspect of this invention aims to provide a method for preparing a carbon-fixing, heat-insulating, high-strength geopolymer material based on industrial and agricultural solid waste. The method involves dissolving an alkali activator in water to prepare an alkali activator solution; dry mixing biomass power plant ash, straw powder, iron tailings sand, and steel slag powder to obtain the industrial and agricultural solid waste admixture; adding the alkali activator solution to the industrial and agricultural solid waste admixture in portions and stirring evenly; pouring the mixture into a mold for curing to obtain the carbon-fixing, heat-insulating, high-strength geopolymer material based on industrial and agricultural solid waste.

[0015] As a preferred embodiment of the present invention, the amount of water added is 15% to 30% of the total mass of the industrial and agricultural solid waste admixture.

[0016] As a further preferred embodiment of the present invention, the addition of the alkaline activator solution to the industrial and agricultural solid waste admixture in portions includes the following steps: slowly pouring two-thirds of the activator solution into the industrial and agricultural solid waste admixture, stirring for 1 to 2 minutes at a speed of less than 120 rpm, then pouring in the remaining alkaline activator solution, and continuing to stir for 1 to 2 minutes at a speed of 150 to 300 rpm.

[0017] As a preferred embodiment of the present invention, the curing is selected from any of the following methods: (1) standard curing for 28 days, followed by curing at room temperature with 95% carbon dioxide concentration and 90% humidity in a carbonization curing box for 2 days; (2) curing in a 90°C water bath for 12 hours, followed by curing at room temperature with 95% carbon dioxide concentration and 90% humidity in a carbonization curing box for 2 days.

[0018] This invention has at least the following technical effects:

[0019] The geopolymer material prepared in this invention uses industrial and agricultural solid waste as admixtures. Straw powder, a fine powder formed from agricultural straw waste after shearing, is lightweight, porous, and contains abundant plant fibers, which can reduce the thermal conductivity of the geopolymer material and improve its insulation performance. The porous and lightweight characteristics of straw powder also contribute to the material's lightweight properties. Biomass power generation ash, collected from the combustion of straw, grain husks, and forest residues in biomass power plants, possesses certain pozzolanic activity and is a good precursor for geopolymer activation. Steel slag and iron tailings sand are mixed into biomass power generation ash. Through the high efficiency of microwave energy absorption by both, the matrix reaction of the geopolymer is promoted, thereby improving the density of the geopolymer matrix. While improving the thermal insulation performance of the material, the compressive strength and durability of the material are guaranteed. This effectively avoids the contradiction between the porous insulation of the material and the high density and strength of the matrix, forming a building thermal insulation material with lightweight and high strength performance. The compressive strength and thermal conductivity of the geopolymer material prepared by this invention are at a good level, which can meet the requirements of integrated structural and functional thermal insulation wall panels.

[0020] The geopolymer material of this invention contains a large amount of steel slag. During the solidification process, a certain amount of high-calcium CASH gel is generated. Through the pore channels formed by straw powder, the ability of the geopolymer to absorb carbon dioxide is enhanced. At the same time, its carbon fixation product is calcium carbonate crystals, which improve the density of the matrix by filling the pores, thereby improving the compressive strength. This realizes the carbon strengthening mechanism of environmental carbon on materials. It should be noted that through the physicochemical synergy of straw powder and steel slag, the carbon fixation efficiency reaches 8%, and the carbon strengthening improvement rate of 180-day compressive strength reaches 10%, that is, the strength is improved by 10% after carbon fixation.

[0021] This invention uses industrial and agricultural solid wastes such as iron tailings, blast furnace slag, biomass power generation ash, and straw powder as admixtures to effectively realize the high-value utilization of industrial and agricultural solid waste in building materials, which is energy-saving and environmentally friendly. It can also reduce the cost and increase the efficiency of building materials, promote the green transformation of high-performance thermal insulation building materials, and has broad market prospects and ecological and environmental benefits. Attached Figure Description

[0022] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0023] Figure 1 The image shows a scanning electron microscope (SEM) image of the high-strength geopolymer material with carbon sequestration and thermal insulation based on industrial and agricultural solid waste prepared in Example 1.

[0024] Figure 2 The image shows the XRD pattern of the high-strength geopolymer material with carbon sequestration and thermal insulation based on industrial and agricultural solid waste prepared in Example 1. Detailed Implementation

[0025] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0026] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0027] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0028] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0029] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0030] This invention discloses a carbon-fixing, heat-insulating, high-strength geopolymer material based on industrial and agricultural solid waste. The material comprises, based on 100% of the industrial and agricultural solid waste admixture, 20%–50% biomass power generation ash, 1%–15% straw powder, 10%–20% iron tailings sand, with the remainder being steel slag powder.

[0031] In some optional embodiments, based on 100% by weight of industrial and agricultural solid waste admixtures, the carbon-fixing and heat-insulating high-strength geopolymer material based on industrial and agricultural solid waste includes: 25% to 30% biomass power generation ash, 3% to 13% straw powder, 10% to 15% iron tailings sand, and the balance being steel slag powder.

[0032] In some preferred embodiments, based on 100% by weight of industrial and agricultural solid waste admixtures, the carbon-fixing and heat-insulating high-strength geopolymer material based on industrial and agricultural solid waste includes: 25% biomass power generation ash, 5% to 10% straw powder, 10% to 15% iron tailings sand, and 45% to 55% steel slag powder.

[0033] Straw powder is a fine powder formed from agricultural straw waste after shearing. It is lightweight, porous, and contains a large amount of plant fiber. In this embodiment of the invention, the straw can include, but is not limited to, corn stalks, sorghum stalks, wheat stalks, rice stalks, and bean stalks. These straws are collected, dried, crushed, and sieved to obtain straw powder. To minimize the particle size of the straw powder, a large mesh size sieve, such as 80 mesh or 100 mesh, should be selected.

[0034] Biomass power generation ash is the ash and fly ash collected after burning waste such as straw, grain husks, and forest residue in biomass power plants. It has a certain degree of pozzolanic activity. Biomass power generation ash is mainly composed of silicon dioxide, magnesium oxide, and calcium oxide, and contains a certain amount of potassium oxide. Its high magnesium oxide and potassium oxide content makes it unsuitable as an admixture for cement concrete. However, it has a high proportion of active SiO2 + Al2O3, making it easily activated by alkalis. Furthermore, its heavy metal content and organic waste emissions are far lower than those of waste incineration fly ash, requiring no secondary treatment. Its pH value is more stable, reducing the likelihood of concrete corrosion, making it one of the ideal precursors for geopolymer concrete. Biomass power generation ash particles often have a very uniform size, with a reasonable and easily controllable silicon-to-calcium ratio, which can optimize the compressive strength and pore structure of geopolymer concrete.

[0035] In some optional embodiments, the carbon-fixing and heat-insulating high-strength geopolymer material based on industrial and agricultural solid waste further includes an alkali activator, the amount of which is 2% to 8% of the alkali equivalent (equivalent potassium oxide).

[0036] In some optional embodiments, the alkali activator comprises potassium silicate and potassium hydroxide; the modulus of the alkali activator is 1.0 to 1.5.

[0037] In some optional embodiments, the steel slag powder is obtained by crushing and grinding blast furnace steel slag, preferably with a particle size of less than 100 micrometers. The steel slag powder contains calcium oxide, silicon dioxide, and aluminum oxide, exhibiting hydraulic properties. The ratio of calcium oxide to silicon dioxide in the steel slag powder is within the optimal range for geopolymer reaction, and using steel slag powder as a geopolymer admixture can optimize the formation of the silicate network structure. Additionally, the steel slag powder contains a small amount of iron oxide, which can enhance the compressive strength and durability of the geopolymer. After ultrafine grinding, the specific surface area is significantly increased, further contributing to the improvement of the compressive strength of the geopolymer.

[0038] Iron tailings sand contains metal oxides such as iron oxide and aluminum oxide, which can optimize the mechanical properties and durability of geopolymers. It also contains a large amount of silica, which is highly compatible with the aluminosilicate activity required for geopolymer reactions, effectively promoting the formation of a three-dimensional network structure and thus improving the mechanical properties of the geopolymers. Furthermore, the surface of iron tailings sand has a microporous structure, which can enhance the bonding strength with other admixtures, thereby reducing interfacial defects.

[0039] The second aspect of this invention aims to provide a method for preparing a carbon-fixing, heat-insulating, high-strength geopolymer material based on industrial and agricultural solid waste. The method involves dissolving an alkali activator in water to prepare an alkali activator solution; dry mixing biomass power plant ash, straw powder, iron tailings sand, and steel slag powder to obtain the industrial and agricultural solid waste admixture; adding the alkali activator solution to the industrial and agricultural solid waste admixture in portions and stirring evenly; pouring the mixture into a mold for curing to obtain the carbon-fixing, heat-insulating, high-strength geopolymer material based on industrial and agricultural solid waste.

[0040] As a preferred embodiment of the present invention, the amount of water added is 15% to 30% of the total mass of the industrial and agricultural solid waste admixture, i.e., the water-cement ratio is 15% to 30%.

[0041] As a further preferred embodiment of the present invention, the addition of the alkaline activator solution to the industrial and agricultural solid waste admixture in portions includes the following steps: slowly pouring two-thirds of the activator solution into the industrial and agricultural solid waste admixture, stirring for 1 to 2 minutes at a speed of less than 120 rpm, then pouring in the remaining alkaline activator solution, and continuing to stir for 1 to 2 minutes at a speed of 150 to 300 rpm.

[0042] As a preferred embodiment of the present invention, the curing is selected from any of the following methods: (1) standard curing for 28 days, followed by curing at room temperature with 95% carbon dioxide concentration and 90% humidity in a carbonization curing box for 2 days; (2) curing in a 90°C water bath for 12 hours, followed by curing at room temperature with 95% carbon dioxide concentration and 90% humidity in a carbonization curing box for 2 days.

[0043] In the following embodiments, the technical specifications of the straw powder are as follows: the straw powder is made from rice straw and passes through a 100-mesh sieve.

[0044] Technical specifications of steel slag powder: average particle size of steel slag powder is 21.7 micrometers, and the ratio of calcium oxide to silicon dioxide is 2.2.

[0045] Technical specifications of iron tailings: The average particle size of iron tailings is 116.2 micrometers, and its silica content is 72%.

[0046] Technical specifications of biomass power generation ash: The average particle size of biomass power generation ash is 38.1 micrometers, the ratio of calcium oxide to silicon dioxide is 0.8, and XRF analysis shows that it contains 8.1% magnesium oxide and 4.6% potassium oxide.

[0047] Quartz sand technical specifications: The average particle size of quartz sand is 129.6 micrometers, and its silica content is 96%.

[0048] Technical specifications for fly ash: average particle size of fly ash is 70.2 micrometers, and the ratio of calcium oxide to silicon dioxide is 0.19.

[0049] Technical specifications for fly ash from municipal solid waste incineration: The average particle size of fly ash from municipal solid waste incineration is 26.5 micrometers, the ratio of calcium oxide to silicon dioxide is 8.8, XRF analysis shows that it contains 8% chloride ions, and heavy metal content analysis shows that the chromium content is 163 mg / kg, the copper content is 680 mg / kg, and the zinc content is 3701 mg / kg.

[0050] It should be noted that any technical means not described in detail in the embodiments of the present invention can be implemented using conventional technical means in the art.

[0051] Example 1

[0052] A high-strength geopolymer material for carbon fixation and thermal insulation based on industrial and agricultural solid waste, comprising, by weight percentage, 30% biomass power generation ash, 45% steel slag powder, 12% iron tailings sand, and 13% straw powder; potassium silicate and potassium hydroxide as alkali activators with a modulus of 1.4 and an alkali equivalent of 4%; and water added during the preparation process is 30% of the total mass of the industrial and agricultural solid waste admixture.

[0053] The preparation method is as follows:

[0054] 1) Weigh out potassium silicate, potassium hydroxide and water according to the above mass proportions, mix for 5 minutes at 100 rpm, and let cool to room temperature to obtain the alkali activator for later use;

[0055] 2) Weigh out the straw powder, steel slag powder, iron tailings sand and biomass power generation ash according to the mass fractions, dry mix for 3 minutes at 100 rpm to obtain the dry admixture;

[0056] 3) Slowly pour two-thirds of the alkali activator obtained in step 1) into the dry admixture obtained in step 2), stir for 2 minutes at 100 rpm, then pour in the remaining alkali activator and continue stirring for 2 minutes at 150 rpm.

[0057] 4) Pour the prepared geopolymer mortar from step 3) into the mold, cover it with a layer of plastic film to seal it, and remove the mold after curing in the mold for 2 days at 20±5℃.

[0058] 5) After demolding in step 4), the specimens were cured under standard conditions for 28 days, and then cured at room temperature with 95% carbon dioxide concentration and 90% humidity in a carbonization curing chamber for 2 days to obtain a high-strength geopolymer material with carbon sequestration and thermal insulation based on industrial and agricultural solid waste.

[0059] The scanning electron microscope image of the high-strength, carbon-fixing, heat-insulating geopolymer material based on industrial and agricultural solid waste prepared in this embodiment is shown below. Figure 1 The lumpy substance in the image is calcium carbonate; see XRD pattern. Figure 2 ,from Figure 2 As can be seen from the data, the high-strength geopolymer material prepared in this embodiment generates characteristic peaks of calcium carbonate crystals after curing, which further confirms the formation of calcium carbonate crystals.

[0060] Example 2

[0061] A high-strength geopolymer material for carbon fixation and thermal insulation based on industrial and agricultural solid waste, comprising, by weight percentage, 30% biomass power generation ash, 50% steel slag powder, 12% iron tailings sand, and 8% straw powder; potassium silicate and potassium hydroxide as alkali activators with a modulus of 1.4 and an alkali equivalent of 4%; and water added during the preparation process at 30% of the total mass of the industrial and agricultural solid waste admixture.

[0062] The preparation method is the same as in Example 1.

[0063] Example 3

[0064] A high-strength geopolymer material for carbon fixation and thermal insulation based on industrial and agricultural solid waste, comprising, by weight percentage, 30% biomass power generation ash, 55% steel slag powder, 12% iron tailings sand, and 3% straw powder; potassium silicate and potassium hydroxide as alkali activators with a modulus of 1.3 and an alkali equivalent of 5%; and water added during the preparation process is 30% of the total mass of the industrial and agricultural solid waste admixture.

[0065] The preparation method is the same as in Example 1.

[0066] Example 4

[0067] A high-strength geopolymer material for carbon fixation and thermal insulation based on industrial and agricultural solid waste, comprising, by weight percentage, 30% biomass power generation ash, 55% steel slag powder, 10% iron tailings sand, and 5% straw powder; potassium silicate and potassium hydroxide as alkali activators with a modulus of 1.3 and an alkali equivalent of 6%; and water added during the preparation process at 20% of the total mass of the industrial and agricultural solid waste admixture.

[0068] The preparation method is the same as in Example 1.

[0069] Example 5

[0070] A high-strength geopolymer material for carbon fixation and thermal insulation based on industrial and agricultural solid waste, comprising, by weight percentage, 25% biomass power generation ash, 55% steel slag powder, 15% iron tailings sand, and 5% straw powder; potassium silicate and potassium hydroxide as alkali activators with a modulus of 1.3 and an alkali equivalent of 6%; and water added during the preparation process at 15% of the total mass of the industrial and agricultural solid waste admixture.

[0071] The preparation method is as follows:

[0072] Weigh out potassium silicate, potassium hydroxide and water according to the above mass proportions, mix for 5 minutes at 100 rpm, and let cool to room temperature to obtain the alkali activator for later use;

[0073] 2) Weigh out the straw powder, steel slag powder, iron tailings sand and biomass power generation ash according to the mass fractions, dry mix for 3 minutes at 100 rpm to obtain the dry admixture;

[0074] 3) Slowly pour two-thirds of the alkali activator obtained in step 1) into the dry admixture obtained in step 2), stir for 2 minutes at 100 rpm, then pour in the remaining alkali activator and continue stirring for 2 minutes at 150 rpm.

[0075] 4) Pour the prepared geopolymer mortar from step 3) into the mold, cover it with a layer of plastic film to seal it, and remove the mold after curing in the mold for 2 days at 20±5℃.

[0076] 5) After demolding in step 4), the specimen is cured in a 90℃ water bath for 12 hours, and then cured in a carbonization curing box at 95% carbon dioxide concentration and 90% humidity at room temperature for 2 days to obtain a carbon-fixing and heat-insulating high-strength geopolymer material based on industrial and agricultural solid waste.

[0077] Example 6

[0078] A high-strength geopolymer material for carbon fixation and thermal insulation based on industrial and agricultural solid waste, comprising, by weight percentage, 30% biomass power generation ash, 52% steel slag powder, 15% iron tailings sand, and 3% straw powder; potassium silicate and potassium hydroxide as alkali activators with a modulus of 1.2 and an alkali equivalent of 7%; and water added during the preparation process at 15% of the total mass of the industrial and agricultural solid waste admixture.

[0079] The preparation method is the same as in Example 5.

[0080] Example 7

[0081] A high-strength geopolymer material for carbon fixation and thermal insulation based on industrial and agricultural solid waste, comprising, by weight percentage, 25% biomass power generation ash, 55% steel slag powder, 11% iron tailings sand, and 9% straw powder; potassium silicate and potassium hydroxide as alkali activators with a modulus of 1.1 and an alkali equivalent of 8%; and water added during the preparation process at 15% of the total mass of the industrial and agricultural solid waste admixture.

[0082] The preparation method is the same as in Example 5.

[0083] Comparative Example 1

[0084] A high-strength geopolymer material for carbon fixation and thermal insulation based on industrial and agricultural solid waste, comprising, by weight percentage, 25% treated fly ash from waste incineration, 55% steel slag powder, 15% iron tailings sand, and 5% straw powder; potassium silicate and potassium hydroxide as alkali activators with a modulus of 1.3 and an alkali equivalent of 6%; and water added during the preparation process at 15% of the total mass of the industrial and agricultural solid waste admixture.

[0085] The preparation method is the same as in Example 5.

[0086] Comparative Example 2

[0087] A high-strength geopolymer material for carbon fixation and thermal insulation based on industrial and agricultural solid waste, comprising, by weight percentage, 25% fly ash, 55% steel slag powder, 15% iron tailings sand, and 5% straw powder; potassium silicate and potassium hydroxide as alkali activators with a modulus of 1.3 and an alkali equivalent of 6%; and water added during the preparation process at 15% of the total mass of the industrial and agricultural solid waste admixture.

[0088] The preparation method is the same as in Example 5.

[0089] Comparative Example 3

[0090] A high-strength geopolymer material for carbon fixation and thermal insulation based on industrial and agricultural solid waste, comprising, by weight percentage, 25% biomass power generation ash, 55% steel slag powder, 15% quartz sand, and 5% straw powder; potassium silicate and potassium hydroxide as alkali activators with a modulus of 1.3 and an alkali equivalent of 6%; and water added during the preparation process at 15% of the total mass of the industrial and agricultural solid waste admixture.

[0091] The preparation method is the same as in Example 5.

[0092] Comparative Example 4

[0093] A high-strength geopolymer material for carbon fixation and thermal insulation based on industrial and agricultural solid waste, comprising, by weight percentage, 5% biomass power generation ash, 80% steel slag powder, 10% iron tailings sand, and 5% straw powder; potassium silicate and potassium hydroxide as alkali activators with a modulus of 1.3 and an alkali equivalent of 6%; and water added during the preparation process at 15% of the total mass of the industrial and agricultural solid waste admixture.

[0094] The preparation method is the same as in Example 5.

[0095] Comparative Example 5

[0096] A high-strength geopolymer material for carbon fixation and thermal insulation based on industrial and agricultural solid waste, comprising, by weight percentage, 80% steel slag powder, 15% iron tailings sand, and 5% straw powder; potassium silicate and potassium hydroxide as alkali activators with a modulus of 0.5 and an alkali equivalent of 2%; and water added during the preparation process at 30% of the total mass of the industrial and agricultural solid waste admixture.

[0097] The preparation method is the same as in Example 5.

[0098] Comparative Example 6

[0099] A high-strength geopolymer material with carbon sequestration and thermal insulation based on industrial and agricultural solid waste, with the same raw material ratio as in Example 6.

[0100] The preparation method is as follows:

[0101] 1) Weigh out potassium silicate, potassium hydroxide and water according to the above mass proportions, mix for 5 minutes at 100 rpm, and let cool to room temperature to obtain the alkali activator for later use;

[0102] 2) Weigh out the straw powder, steel slag powder, iron tailings sand and biomass power generation ash according to the mass fractions and dry mix for 3 minutes at a speed of 100 rpm to obtain the dry admixture; add the alkali activator prepared in step 1) to the dry admixture and continue stirring for 3 minutes to obtain the geopolymer mortar.

[0103] 3) Pour the geopolymer mortar into the mold, cover it with a layer of plastic film to seal it, and remove the mold after curing in the mold for 2 days at 20±5℃.

[0104] 4) After demolding in step 3), the specimens are cured in a 90℃ water bath for 12 hours to obtain a high-strength geopolymer material based on industrial and agricultural solid waste.

[0105] The performance of the high-strength, carbon-fixing, heat-insulating geopolymer materials based on industrial and agricultural solid waste prepared in Examples 1-7 and Comparative Examples 1-6 was tested. The density measurement specimens were 40mm × 40mm × 40mm in size, and the test method involved measuring the specimen mass.

[0106] The test specimen for compressive strength is 40mm×40mm×40mm. The test method is uniaxial compression (JGJ / T702009). The compressive strength is taken as the average strength of three specimens. The compressive strength is more than 60MPa and it is considered high-strength concrete.

[0107] The test specimen for thermal insulation performance is 300mm×300mm×30mm, and the test method is the determination of thermal conductivity (GB / T10294-2008).

[0108] The carbon fixation performance was tested using the TG test.

[0109] The heavy metal leaching test method shall be performed in accordance with the standard GB / T 41058-2021, and the acceptance standard shall be performed in accordance with GB / T 30760-2024.

[0110] The performance test results of the high-strength geopolymer materials based on industrial and agricultural solid waste prepared in Examples 1-7 and Comparative Examples 1-6 are shown in Table 1.

[0111] Table 1

[0112]

[0113]

[0114] As shown in Table 1:

[0115] (1) The density of the example is less than 1850 kg / m³ 3 With a compressive strength higher than 60MPa, a thermal conductivity lower than 0.18W / (mK), and a carbon fixation efficiency higher than 7%, it belongs to high-strength geopolymer material with carbon fixation and thermal insulation.

[0116] (2) Compared with Example 5, Comparative Example 1 has lower compressive strength, thermal insulation performance and carbon fixation effect than Example 5. This indicates that the use of municipal solid waste incineration fly ash in the system of this invention will seriously reduce the material performance. Moreover, municipal solid waste incineration fly ash must be pretreated to avoid heavy metal ion leaching and environmental pollution, which increases economic costs.

[0117] (3) Compared with Example 5, Comparative Example 2 has lower compressive strength, thermal insulation performance and carbon fixation effect than Example 5, and does not meet the standard of high-strength concrete. This shows that biomass power generation ash can more effectively improve the material performance of the system of the present invention than fly ash.

[0118] (4) Compared with Example 5, the material density and thermal conductivity of Comparative Example 3 are significantly higher than those of Example 5, which does not meet the requirements of lightweight and high strength. Furthermore, quartz sand is a mineral resource, not a solid waste, indicating that tailings sand can effectively improve the lightweight and high strength properties of the system of the present invention compared with quartz sand.

[0119] (5) Compared with Example 5, Comparative Example 4 showed that its carbon fixation effect and heat preservation performance were significantly lower than those of Example 5. It did not meet the high carbon fixation and heat preservation properties of the material, indicating that insufficient biomass power generation ash content would reduce the carbon fixation and heat preservation performance of the material.

[0120] (6) Compared with Example 5, Comparative Example 5 showed that its compressive strength and carbon fixation performance were significantly lower than those of Example 5, and it did not meet the requirements of high strength and carbon fixation properties of the material. This indicates that the modulus and alkali content will affect the carbon fixation performance and mechanical properties of the material.

[0121] (7) Compared with Example 6, Comparative Example 6 showed that its carbon fixation performance was significantly lower than that of Example 6, and it did not meet the carbon fixation properties of the material, indicating that the curing method would affect the carbon fixation performance of the material.

[0122] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A high-strength geopolymer material for carbon sequestration and thermal insulation based on industrial and agricultural solid waste, characterized in that, Based on 100% of the industrial and agricultural solid waste admixture, it includes: 20%–50% biomass power generation ash, 1%–15% straw powder, 10%–20% iron tailings sand, and the remainder is steel slag powder.

2. The high-strength, carbon-fixing, heat-insulating geopolymer material based on industrial and agricultural solid waste according to claim 1, characterized in that, Based on 100% of the industrial and agricultural solid waste admixture, it includes: 25%–30% biomass power generation ash, 3%–13% straw powder, 10%–15% iron tailings sand, and the remainder is steel slag powder.

3. The high-strength, carbon-fixing, heat-insulating geopolymer material based on industrial and agricultural solid waste according to claim 2, characterized in that, Based on 100% of the quality of industrial and agricultural solid waste admixtures, it includes: 25% biomass power generation ash, 5% to 10% straw powder, 10% to 15% iron tailings sand, and 45% to 55% steel slag powder.

4. The high-strength, carbon-fixing, heat-insulating geopolymer material based on industrial and agricultural solid waste according to any one of claims 1 to 3, characterized in that, It also includes alkali activators, the amount of which is calculated as 4% to 8% of the alkali equivalent.

5. The high-strength, carbon-fixing, heat-insulating geopolymer material based on industrial and agricultural solid waste according to any one of claims 1 to 3, characterized in that, The alkaline activator includes potassium silicate and potassium hydroxide; the modulus of the alkaline activator is 1.0 to 1.

5.

6. The high-strength, carbon-fixing, heat-insulating geopolymer material based on industrial and agricultural solid waste according to any one of claims 1 to 3, characterized in that, The particle size of the steel slag powder is less than 100 micrometers.

7. A method for preparing a high-strength, carbon-fixing, heat-insulating geopolymer material based on industrial and agricultural solid waste as described in any one of claims 1 to 6, characterized in that, The alkali activator is dissolved in water to prepare an alkali activator solution. The biomass power generation ash, straw powder, iron tailings sand and steel slag powder are dry-mixed to obtain the industrial and agricultural solid waste admixture. The alkali activator solution is added to the industrial and agricultural solid waste admixture in several batches and stirred evenly. The mixture is poured into a mold for curing to obtain the carbon-fixing, heat-insulating, high-strength geopolymer material based on industrial and agricultural solid waste.

8. The preparation method according to claim 7, characterized in that, The amount of water added is 15% to 30% of the total mass of the industrial and agricultural solid waste admixture.

9. The preparation method according to claim 7, characterized in that, The process of adding the alkaline activator solution to the industrial and agricultural solid waste admixture in portions includes the following steps: slowly pouring two-thirds of the activator solution into the industrial and agricultural solid waste admixture, stirring for 1 to 2 minutes at a speed of less than 120 rpm, then pouring in the remaining alkaline activator solution, and continuing to stir for 1 to 2 minutes at a speed of 150 to 300 rpm.

10. The preparation method according to claim 7, characterized in that, The curing is selected from any of the following methods: (1) standard curing for 28 days, followed by curing at room temperature with 95% carbon dioxide concentration and 90% humidity in a carbonization curing box for 2 days; (2) water bath curing at 90℃ for 12 hours, followed by curing at room temperature with 95% carbon dioxide concentration and 90% humidity in a carbonization curing box for 2 days.

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