A new wall material based on coal gangue and cement sintering and a preparation method thereof

Abstract

The present application relates to the field of new wall material preparation, in particular to a new wall material based on coal gangue and cement sintering and a preparation method thereof. The present application provides an innovative preparation method of coal gangue cement-based composite material. By introducing a new expanding agent and a mineral additive into the traditional cement-based composite material, the present application breaks through the limitations of the prior art and obtains a wall material with higher comprehensive performance and lower cost. The material is not only suitable for the construction industry, but also can be widely used in other fields, such as environmental protection and infrastructure construction.

Description

Technical Field

[0001] This invention relates to the field of new wall material preparation, specifically to a novel wall material based on coal gangue and cement sintering and its preparation method. Background Technology

[0002] With the continuous advancement of industrialization and urbanization, the demand for building materials is increasing daily. Cement-based composite materials, as commonly used materials in construction engineering, have always been a research hotspot for improving their performance and reducing their costs. Traditional cement-based materials often have certain limitations in terms of thermal insulation, sound insulation, earthquake resistance, and corrosion resistance. Coal gangue, as an industrial by-product, has good application potential. However, traditional coal gangue building materials suffer from technical bottlenecks such as uneven pore structure and difficulty in synergistically improving mechanical and thermal insulation properties, which prevents the full realization of their physical properties and structural optimization. Although existing technologies have attempted to introduce single expanding agents or mineral admixtures, they have the following shortcomings: physical foaming agents lead to uneven pore distribution and significant attenuation of mechanical properties; mineral additives have a single modification effect and cannot simultaneously improve thermal insulation and durability; and there is a lack of deep chemical regulation mechanisms for the active components of coal gangue. Therefore, exploring new preparation methods for coal gangue and cement-based composite materials, especially by introducing expanding agents and mineral additives to improve their performance, is a major challenge in current technology. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention aims to provide a novel wall material based on coal gangue and cement sintering, and its preparation method. This novel wall material is produced by introducing novel expanding agents and mineral additives into traditional cement-based composite materials. This invention overcomes the limitations of existing technologies, resulting in a wall material with higher overall performance and lower cost. This material is not only suitable for the construction industry but can also be widely used in other fields, such as environmental protection and infrastructure construction.

[0004] This invention discloses a method for preparing a novel wall material based on coal gangue and cement sintering, comprising the following preparation steps:

[0005] S1 Raw Material Processing: The coal gangue is crushed, calcined in a nitrogen atmosphere, and then mixed with cement to obtain a mixed base material;

[0006] S2 two-component composite: Organic expanding agent and mineral additive are ball-milled and blended to form nanoscale composite powder;

[0007] S3 Wet mixing: The mixed base material prepared in step S1 and the nano-composite powder prepared in step S2 are mixed with water to obtain a suspension. Then, latex and polycarboxylate superplasticizer are added and mixed evenly. During the mixing process, the stirring speed is controlled to increase in a stepwise manner. After the dispersion is even, the molding pressure is set to perform molding to obtain a new wall material molded form.

[0008] S4 Calcination and Forming: The new wall material obtained in step S3 is molded and sintered in stages at varying temperatures. After sintering, it is steam cured to obtain the new wall material.

[0009] Preferably, in the raw material processing step S1, the particle size of the crushed coal gangue is <15μm; the mass ratio of the coal gangue to cement is 1:(0.1~0.5).

[0010] Preferably, in the S2 two-component compounding step, the organic expanding agent is composed of calcium stearate and azodicarbonamide in a mass ratio of 1:(5-8).

[0011] Preferably, in the S2 two-component compounding step, the mineral additive is composed of phosphoaluminate and metakaolin in a mass ratio of 1:(1.5-2).

[0012] Preferably, in the S2 two-component compounding step, the mass ratio of the organic expanding agent to the mineral additive is 1:(5-7).

[0013] Preferably, in the S3 wet mixing step, the weight parts of the mixed base material are 70 parts; the weight parts of the nano-composite powder are 12 parts; the weight parts of water are 20 parts; the weight parts of the polycarboxylate superplasticizer are 3 parts; and the weight parts of the latex are 7 parts.

[0014] Preferably, in the S3 wet mixing step, the stirring speed is divided into four stages: low speed 200 rpm for 3 min; medium speed 450 rpm for 10 min; high speed 800 rpm for 5 min; and low speed 150 rpm for 2 min.

[0015] Preferably, in the S4 calcination and forming step, the segmented variable-temperature sintering is divided into three stages: the first stage is the pre-expansion stage, with a temperature range of 80–160℃, a heating rate of 5℃ / min, and a holding time of 0.5h; the second stage is the crystal reconstruction stage, with a temperature range of 160–650℃, a heating rate of 2℃ / min, and a holding time of 1.5h; and the third stage is the strength development stage, with a temperature range of 650–900℃, a heating rate of 1.5℃ / min, and a holding time of 2h.

[0016] Preferably, in the S4 calcination and forming step, the steam curing temperature is 80°C, the relative humidity is 95%, and the curing time is 15 hours.

[0017] A novel wall material prepared by any of the above-mentioned methods for preparing novel wall materials based on coal gangue and cement sintering.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] This invention provides a novel wall material based on coal gangue and cement sintering, and its preparation method, which has the following beneficial effects:

[0020] (1) Due to the introduction of the expanding agent, a large number of microporous structures are formed inside the material after sintering, which has excellent thermal insulation properties. According to the test, its thermal conductivity is more than 30% lower than that of traditional cement-based materials.

[0021] (2) The formation of microporous structure also effectively improves the sound insulation performance of the material, making it suitable for building environments that require sound insulation.

[0022] (3) During the sintering process, the material forms a lightweight foam structure through the action of the expanding agent, which enhances its toughness and elasticity and significantly improves its seismic resistance.

[0023] (4) The synergistic effect of mineral additives improves the microstructure of the material, thereby enhancing its resistance to acid and alkali corrosion and significantly improving its durability compared to traditional cement materials.

[0024] (5) This invention proposes for the first time the synergistic mechanism of azodicarbonamide-calcium stearate composite expansion system (organic expansion agent) and phosphoaluminate-meta-kaolin mineral additive; constructs a three-level reaction path of "chemical expansion-crystal reconstruction-interface strengthening" to achieve precise control of the microstructure of the material; and achieves the unity of lightweight and high strength.

[0025] (6) Develop segmented temperature-controlled sintering process to ensure the spatiotemporal matching of reaction kinetics and thermodynamic process.

[0026] (7) After natural cooling, steam curing is carried out to promote the secondary reaction of unhydrated particles. Detailed Implementation

[0027] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0028] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0029] Example 1: A method for preparing a novel wall material based on coal gangue and cement sintering, comprising the following steps:

[0030] S1 Raw Material Processing: The coal gangue is crushed to a particle size of <15μm; then calcined under a nitrogen atmosphere, with the calcination temperature controlled at 800℃ and the calcination time at 1.2h. After the coal gangue is calcined and modified, it is mixed with cement at a mass ratio of 1:0.1 to obtain a mixed base material.

[0031] S2 Two-Component Composite: Organic expanding agent and mineral additives are added to a mixer at a mass ratio of 1:5 and ball-milled to form nano-scale composite powder; wherein, the organic expanding agent is composed of calcium stearate and azodicarbonamide at a mass ratio of 1:5; and the mineral additives are composed of phosphoaluminate and metakaolin at a mass ratio of 1:1.5.

[0032] S3 Wet Mixing:

[0033] A suspension was prepared by uniformly mixing 70 parts by weight of the base material, 12 parts by weight of the nano-composite powder, and 20 parts by weight of water. Then, 3 parts by weight of polycarboxylate superplasticizer and 7 parts by weight of latex were added to the suspension and mixed thoroughly. During mixing, the stirring speed was controlled to increase in a stepped manner, divided into four stages: low speed 200 rpm for 3 minutes; medium speed 450 rpm for 10 minutes; high speed 800 rpm for 5 minutes; and low speed 150 rpm for 2 minutes. After uniform dispersion, molding pressure was set for compression molding to obtain the molded form of the new wall material.

[0034] S4 Calcination and Forming: The new wall material molded in step S3 is subjected to segmented variable-temperature sintering. The first stage is the pre-expansion stage, with a temperature range of 80–160℃, a heating rate of 5℃ / min, and a holding time of 0.5h. The second stage is the crystal reconstruction stage, with a temperature range of 160–650℃, a heating rate of 2℃ / min, and a holding time of 1.5h. The third stage is the strength development stage, with a temperature range of 650–900℃, a heating rate of 1.5℃ / min, and a holding time of 2h. After sintering, steam curing is performed at a temperature of 80℃, a relative humidity of 95%, and a curing time of 15h, finally yielding the new wall material.

[0035] Example 2: A method for preparing a novel wall material based on coal gangue and cement sintering, comprising the following steps:

[0036] S1 Raw Material Processing: The coal gangue is crushed to a particle size of <15μm; then calcined under a nitrogen atmosphere, with the calcination temperature controlled at 820℃ and the calcination time at 1.4h. After the coal gangue is calcined and modified, it is mixed with cement at a mass ratio of 1:0.2 to obtain a mixed base material.

[0037] S2 Two-Component Composite: Organic expanding agent and mineral additives are added to a mixer at a mass ratio of 1:5.5 and ball-milled to form nano-scale composite powder; wherein, the organic expanding agent is composed of calcium stearate and azodicarbonamide at a mass ratio of 1:5; and the mineral additives are composed of phosphoaluminate and metakaolin at a mass ratio of 1:1.5.

[0038] S3 Wet Mixing:

[0039] A suspension was prepared by uniformly mixing 70 parts by weight of the base material, 12 parts by weight of the nano-composite powder, and 20 parts by weight of water. Then, 3 parts by weight of polycarboxylate superplasticizer and 7 parts by weight of latex were added to the suspension and mixed thoroughly. During mixing, the stirring speed was controlled to increase in a stepped manner, divided into four stages: low speed 200 rpm for 3 minutes; medium speed 450 rpm for 10 minutes; high speed 800 rpm for 5 minutes; and low speed 150 rpm for 2 minutes. After uniform dispersion, molding pressure was set for compression molding to obtain the molded form of the new wall material.

[0040] S4 Calcination and Forming: The new wall material molded in step S3 is subjected to segmented variable-temperature sintering. The first stage is the pre-expansion stage, with a temperature range of 80–160℃, a heating rate of 5℃ / min, and a holding time of 0.5h. The second stage is the crystal reconstruction stage, with a temperature range of 160–650℃, a heating rate of 2℃ / min, and a holding time of 1.5h. The third stage is the strength development stage, with a temperature range of 650–900℃, a heating rate of 1.5℃ / min, and a holding time of 2h. After sintering, steam curing is performed at a temperature of 80℃, a relative humidity of 95%, and a curing time of 15h, finally yielding the new wall material.

[0041] Example 3: A method for preparing a novel wall material based on coal gangue and cement sintering, comprising the following steps:

[0042] S1 Raw Material Processing: The coal gangue is crushed to a particle size of <15μm; then calcined in a nitrogen atmosphere at a controlled calcination temperature of 840℃ for 1.6h. After the coal gangue is calcined and modified, it is mixed with cement at a mass ratio of 1:0.3 to obtain a mixed base material.

[0043] S2 Two-Component Composite: Organic expanding agent and mineral additives are added to a mixer at a mass ratio of 1:6 and ball-milled to form nano-scale composite powder; wherein, the organic expanding agent is composed of calcium stearate and azodicarbonamide at a mass ratio of 1:5; and the mineral additives are composed of phosphoaluminate and metakaolin at a mass ratio of 1:1.5.

[0044] S3 Wet Mixing:

[0045] A suspension was prepared by uniformly mixing 70 parts by weight of the base material, 12 parts by weight of the nano-composite powder, and 20 parts by weight of water. Then, 3 parts by weight of polycarboxylate superplasticizer and 7 parts by weight of latex were added to the suspension and mixed thoroughly. During mixing, the stirring speed was controlled to increase in a stepped manner, divided into four stages: low speed 200 rpm for 3 minutes; medium speed 450 rpm for 10 minutes; high speed 800 rpm for 5 minutes; and low speed 150 rpm for 2 minutes. After uniform dispersion, molding pressure was set for compression molding to obtain the molded form of the new wall material.

[0046] S4 Calcination and Forming: The new wall material molded in step S3 is subjected to segmented variable-temperature sintering. The first stage is the pre-expansion stage, with a temperature range of 80–160℃, a heating rate of 5℃ / min, and a holding time of 0.5h. The second stage is the crystal reconstruction stage, with a temperature range of 160–650℃, a heating rate of 2℃ / min, and a holding time of 1.5h. The third stage is the strength development stage, with a temperature range of 650–900℃, a heating rate of 1.5℃ / min, and a holding time of 2h. After sintering, steam curing is performed at a temperature of 80℃, a relative humidity of 95%, and a curing time of 15h, finally yielding the new wall material.

[0047] Example 4: A method for preparing a novel wall material based on coal gangue and cement sintering, comprising the following steps:

[0048] S1 Raw Material Processing: The coal gangue is crushed to a particle size of <15μm; then calcined under a nitrogen atmosphere, with the calcination temperature controlled at 860℃ and the calcination time at 1.8h. After the coal gangue is calcined and modified, it is mixed with cement at a mass ratio of 1:0.4 to obtain a mixed base material.

[0049] S2 Two-Component Composite: Organic expanding agent and mineral additives are added to a mixer at a mass ratio of 1:6.5 and ball-milled to form nano-scale composite powder; wherein, the organic expanding agent is composed of calcium stearate and azodicarbonamide at a mass ratio of 1:5; and the mineral additives are composed of phosphoaluminate and metakaolin at a mass ratio of 1:1.5.

[0050] S3 Wet Mixing:

[0051] A suspension was prepared by uniformly mixing 70 parts by weight of the base material, 12 parts by weight of the nano-composite powder, and 20 parts by weight of water. Then, 3 parts by weight of polycarboxylate superplasticizer and 7 parts by weight of latex were added to the suspension and mixed thoroughly. During mixing, the stirring speed was controlled to increase in a stepped manner, divided into four stages: low speed 200 rpm for 3 minutes; medium speed 450 rpm for 10 minutes; high speed 800 rpm for 5 minutes; and low speed 150 rpm for 2 minutes. After uniform dispersion, molding pressure was set for compression molding to obtain the molded form of the new wall material.

[0052] S4 Calcination and Forming: The new wall material molded in step S3 is subjected to segmented variable-temperature sintering. The first stage is the pre-expansion stage, with a temperature range of 80–160℃, a heating rate of 5℃ / min, and a holding time of 0.5h. The second stage is the crystal reconstruction stage, with a temperature range of 160–650℃, a heating rate of 2℃ / min, and a holding time of 1.5h. The third stage is the strength development stage, with a temperature range of 650–900℃, a heating rate of 1.5℃ / min, and a holding time of 2h. After sintering, steam curing is performed at a temperature of 80℃, a relative humidity of 95%, and a curing time of 15h, finally yielding the new wall material.

[0053] Example 5: A method for preparing a novel wall material based on coal gangue and cement sintering, comprising the following steps:

[0054] S1 Raw Material Processing: The coal gangue is crushed to a particle size of <15μm; then calcined under a nitrogen atmosphere, with the calcination temperature controlled at 880℃ and the calcination time at 2.0h. After the coal gangue is calcined and modified, it is mixed with cement at a mass ratio of 1:0.5 to obtain a mixed base material.

[0055] S2 Two-Component Composite: Organic expanding agent and mineral additives are added to a mixer at a mass ratio of 1:7 and ball-milled to form nano-scale composite powder; wherein, the organic expanding agent is composed of calcium stearate and azodicarbonamide at a mass ratio of 1:5; and the mineral additives are composed of phosphoaluminate and metakaolin at a mass ratio of 1:1.5.

[0056] S3 Wet Mixing:

[0057] A suspension was prepared by uniformly mixing 70 parts by weight of the base material, 12 parts by weight of the nano-composite powder, and 20 parts by weight of water. Then, 3 parts by weight of polycarboxylate superplasticizer and 7 parts by weight of latex were added to the suspension and mixed thoroughly. During mixing, the stirring speed was controlled to increase in a stepped manner, divided into four stages: low speed 200 rpm for 3 minutes; medium speed 450 rpm for 10 minutes; high speed 800 rpm for 5 minutes; and low speed 150 rpm for 2 minutes. After uniform dispersion, molding pressure was set for compression molding to obtain the molded form of the new wall material.

[0058] S4 Calcination and Forming: The new wall material molded in step S3 is subjected to segmented variable-temperature sintering. The first stage is the pre-expansion stage, with a temperature range of 80–160℃, a heating rate of 5℃ / min, and a holding time of 0.5h. The second stage is the crystal reconstruction stage, with a temperature range of 160–650℃, a heating rate of 2℃ / min, and a holding time of 1.5h. The third stage is the strength development stage, with a temperature range of 650–900℃, a heating rate of 1.5℃ / min, and a holding time of 2h. After sintering, steam curing is performed at a temperature of 80℃, a relative humidity of 95%, and a curing time of 15h, finally yielding the new wall material.

[0059] Example 6: A method for preparing a novel wall material based on coal gangue and cement sintering, comprising the following steps:

[0060] S1 Raw Material Processing: The coal gangue is crushed to a particle size of <15μm; then calcined under a nitrogen atmosphere, with the calcination temperature controlled at 880℃ and the calcination time at 2.0h. After the coal gangue is calcined and modified, it is mixed with cement at a mass ratio of 1:0.5 to obtain a mixed base material.

[0061] S2 two-component composite: An organic expanding agent is added to a mixer and ball-milled to form nano-sized powder; wherein, the organic expanding agent is composed of calcium stearate and azodicarbonamide in a mass ratio of 1:5.

[0062] S3 Wet Mixing:

[0063] A suspension was prepared by uniformly mixing 70 parts by weight of the base material, 12 parts by weight of the nano-composite powder, and 20 parts by weight of water. Then, 3 parts by weight of polycarboxylate superplasticizer and 7 parts by weight of latex were added to the suspension and mixed thoroughly. During mixing, the stirring speed was controlled to increase in a stepped manner, divided into four stages: low speed 200 rpm for 3 minutes; medium speed 450 rpm for 10 minutes; high speed 800 rpm for 5 minutes; and low speed 150 rpm for 2 minutes. After uniform dispersion, molding pressure was set for compression molding to obtain the molded form of the new wall material.

[0064] S4 Calcination and Forming: The new wall material molded in step S3 is subjected to segmented variable-temperature sintering. The first stage is the pre-expansion stage, with a temperature range of 80–160℃, a heating rate of 5℃ / min, and a holding time of 0.5h. The second stage is the crystal reconstruction stage, with a temperature range of 160–650℃, a heating rate of 2℃ / min, and a holding time of 1.5h. The third stage is the strength development stage, with a temperature range of 650–900℃, a heating rate of 1.5℃ / min, and a holding time of 2h. After sintering, steam curing is performed at a temperature of 80℃, a relative humidity of 95%, and a curing time of 15h, finally yielding the new wall material.

[0065] Example 7: A method for preparing a novel wall material based on coal gangue and cement sintering, comprising the following steps:

[0066] S1 Raw Material Processing: The coal gangue is crushed to a particle size of <15μm; then calcined under a nitrogen atmosphere, with the calcination temperature controlled at 880℃ and the calcination time at 2.0h. After the coal gangue is calcined and modified, it is mixed with cement at a mass ratio of 1:0.5 to obtain a mixed base material.

[0067] S2 two-component composite: mineral additives are added to a mixer and ball-milled to form nano-sized powders; wherein, the mineral additives are composed of phosphoaluminate and metakaolin in a mass ratio of 1:1.5.

[0068] S3 Wet Mixing:

[0069] A suspension was prepared by uniformly mixing 70 parts by weight of the base material, 12 parts by weight of the nano-composite powder, and 20 parts by weight of water. Then, 3 parts by weight of polycarboxylate superplasticizer and 7 parts by weight of latex were added to the suspension and mixed thoroughly. During mixing, the stirring speed was controlled to increase in a stepped manner, divided into four stages: low speed 200 rpm for 3 minutes; medium speed 450 rpm for 10 minutes; high speed 800 rpm for 5 minutes; and low speed 150 rpm for 2 minutes. After uniform dispersion, molding pressure was set for compression molding to obtain the molded form of the new wall material.

[0070] S4 Calcination and Forming: The new wall material molded in step S3 is subjected to segmented variable-temperature sintering. The first stage is the pre-expansion stage, with a temperature range of 80–160℃, a heating rate of 5℃ / min, and a holding time of 0.5h. The second stage is the crystal reconstruction stage, with a temperature range of 160–650℃, a heating rate of 2℃ / min, and a holding time of 1.5h. The third stage is the strength development stage, with a temperature range of 650–900℃, a heating rate of 1.5℃ / min, and a holding time of 2h. After sintering, steam curing is performed at a temperature of 80℃, a relative humidity of 95%, and a curing time of 15h, finally yielding the new wall material.

[0071] Example 8: A method for preparing a novel wall material based on coal gangue and cement sintering, comprising the following steps:

[0072] S1 Raw Material Processing: The coal gangue is crushed to a particle size of <15μm; then calcined under a nitrogen atmosphere, with the calcination temperature controlled at 880℃ and the calcination time at 2.0h. After the coal gangue is calcined and modified, it is mixed with cement at a mass ratio of 1:0.5 to obtain a mixed base material.

[0073] S2 Two-Component Composite: Organic expanding agent and mineral additives are added to a mixer at a mass ratio of 1:7 and ball-milled to form nano-scale composite powder; wherein, the organic expanding agent is composed of calcium stearate and azodicarbonamide at a mass ratio of 1:5; and the mineral additives are composed of phosphoaluminate and metakaolin at a mass ratio of 1:1.5.

[0074] S3 Wet Mixing:

[0075] A suspension was obtained by mixing 70 parts by weight of the base material, 12 parts by weight of the nano-composite powder, and 20 parts by weight of water. Then, 3 parts by weight of polycarboxylate superplasticizer and 7 parts by weight of latex were added to the suspension and mixed evenly. During the mixing process, the stirring speed was controlled at 500 rpm and stirred for 20 minutes. After the mixture was evenly dispersed, the molding pressure was set and the material was molded to obtain a molded new wall material.

[0076] S4 Calcination and Forming: The new wall material molded in step S3 is subjected to segmented variable-temperature sintering. The first stage is the pre-expansion stage, with a temperature range of 80–160℃, a heating rate of 5℃ / min, and a holding time of 0.5h. The second stage is the crystal reconstruction stage, with a temperature range of 160–650℃, a heating rate of 2℃ / min, and a holding time of 1.5h. The third stage is the strength development stage, with a temperature range of 650–900℃, a heating rate of 1.5℃ / min, and a holding time of 2h. After sintering, steam curing is performed at a temperature of 80℃, a relative humidity of 95%, and a curing time of 15h, finally yielding the new wall material.

[0077] Example 9: A method for preparing a novel wall material based on coal gangue and cement sintering, comprising the following steps:

[0078] S1 Raw Material Processing: The coal gangue is crushed to a particle size of <15μm; then calcined under a nitrogen atmosphere, with the calcination temperature controlled at 880℃ and the calcination time at 2.0h. After the coal gangue is calcined and modified, it is mixed with cement at a mass ratio of 1:0.5 to obtain a mixed base material.

[0079] S2 Two-Component Composite: Organic expanding agent and mineral additives are added to a mixer at a mass ratio of 1:7 and ball-milled to form nano-scale composite powder; wherein, the organic expanding agent is composed of calcium stearate and azodicarbonamide at a mass ratio of 1:5; and the mineral additives are composed of phosphoaluminate and metakaolin at a mass ratio of 1:1.5.

[0080] S3 Wet Mixing:

[0081] A suspension was prepared by uniformly mixing 70 parts by weight of the base material, 12 parts by weight of the nano-composite powder, and 20 parts by weight of water. Then, 3 parts by weight of polycarboxylate superplasticizer and 7 parts by weight of latex were added to the suspension and mixed thoroughly. During mixing, the stirring speed was controlled to increase in a stepped manner, divided into four stages: low speed 200 rpm for 3 minutes; medium speed 450 rpm for 10 minutes; high speed 800 rpm for 5 minutes; and low speed 150 rpm for 2 minutes. After uniform dispersion, molding pressure was set for compression molding to obtain the molded form of the new wall material.

[0082] S4 Calcination and Molding: The new wall material obtained in step S3 is sintered by molding at a temperature range of 650-900℃ and a heating rate of 5℃ / min. After sintering, steam curing is carried out at a temperature of 80℃ and a relative humidity of 95% for 15 hours to obtain the new wall material.

[0083] The performance of the new wall materials prepared in Examples 1-9 was tested (thermal insulation, sound insulation, seismic resistance, and corrosion resistance). The test results are shown in the table below:

[0084]

[0085] As shown in the table above, the data from Examples 1-5 indicate that with the increase in calcination temperature of coal gangue (from 800℃ to 880℃), the extension of calcination time (from 1.2h to 2.0h), and the increase in the proportion of cement in the coal gangue-cement mixture (from 1:0.1 to 1:0.5), all properties of the new wall material show a significant improvement trend. Regarding thermal insulation performance, the thermal conductivity gradually decreases, indicating an improvement in the material's thermal insulation properties. Regarding sound insulation performance, the sound insulation gradually increases, indicating an enhanced ability to block sound. Regarding seismic performance, the ductility ratio gradually increases, meaning that the material's deformation capacity and energy dissipation capacity under seismic action are enhanced. Regarding corrosion resistance, the mass loss rate gradually decreases, indicating an improvement in the material's durability in corrosive environments.

[0086] Example 6 involved the preparation of the material without the addition of mineral additives, and Example 7 involved the preparation of the material without the addition of organic expanding agents. Compared with Example 5, the absence of mineral additives in Example 6 resulted in a decrease in all properties of the novel wall material. Compared with Example 5, the absence of organic expanding agents in Example 7 significantly affected the performance of the novel wall material. This is because azodicarbonamide decomposes to produce nitrogen and carbon dioxide gases, forming micropores in the material. Calcium stearate can reduce interfacial tension and regulate the pore morphology to a spherical closed-pore structure. Phosphoaluminate provides phosphate and tetrahydroxyaluminate groups, which can promote the transformation of CSH gel to tobermorite crystal form, and metakaolinite can strengthen the interfacial transition zone. The micropores generated by the organic expanding agent provide nucleation sites for the crystal reconstruction of mineral additives, and the hydration products of mineral additives fill the surface defects of the pores, forming a "rigid-flexible" pore wall structure, which significantly improves the compressive strength of the novel wall material.

[0087] Example 8 did not involve step-by-step mixing. Compared to Example 5, the absence of step-by-step mixing had a certain impact on the performance of the novel wall material. This is because step-by-step mixing gradually improves the mixing uniformity of the materials, which helps to form a denser microstructure, reduces porosity and defects, and thus improves the thermal insulation, sound insulation, seismic resistance, and corrosion resistance of the novel wall material.

[0088] Example 9 did not involve segmented calcination. Compared to Example 5, the lack of segmented calcination resulted in a decrease in all properties of the new wall material. This is because segmented calcination allows for the control of the pore structure. The hierarchical pore design reduces the thermal conductivity of the sintered porous brick while maintaining a porosity of over 80%, thus combining thermal insulation performance with structural stability. Segmented calcination promotes the solid solution of impurity oxides, forming substitutional or interstitial solid solutions, and enhancing grain boundary bonding. It also has energy-saving and environmentally friendly effects.

[0089] Example 10: Screening of the mass ratio of calcium stearate to azodicarbonamide in organic expanding agents; the screening results are shown in the table below:

[0090]

[0091] The data in the table above shows that the overall performance of the new wall material is optimal when the mass ratio of calcium stearate to azodicarbonamide is 1:5. At this ratio, the material exhibits excellent performance in terms of thermal insulation, sound insulation, earthquake resistance, and corrosion resistance. An appropriate mass ratio of calcium stearate to azodicarbonamide can effectively improve the material's performance, but excessive use can lead to negative effects. Therefore, in practical applications, the mass ratio of calcium stearate to azodicarbonamide should be strictly controlled to ensure that the new wall material achieves the best overall performance.

[0092] Example 11: Screening of the mass ratio of phosphoaluminate to metakaolin in mineral additives; the screening results are shown in the table below:

[0093]

[0094] The data in the table above shows that the comprehensive performance of the new wall material is optimal when the mass ratio of phosphoaluminate to metakaolin is 1:1.7. At this ratio, the material exhibits excellent performance in terms of thermal insulation, sound insulation, earthquake resistance, and corrosion resistance. An appropriate mass ratio of phosphoaluminate to metakaolin can effectively improve the material's performance, but excessive or insufficient amounts will lead to negative effects. Therefore, in practical applications, the mass ratio of phosphoaluminate to metakaolin should be strictly controlled to ensure that the new wall material has the best comprehensive performance.

[0095] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a novel wall material based on coal gangue and cement sintering, characterized in that, Includes the following steps: S1 Raw Material Processing: The coal gangue is crushed, calcined in a nitrogen atmosphere, and then mixed with cement to obtain a mixed base material; S2 two-component composite: Organic expanding agent and mineral additive are ball-milled and blended to form nanoscale composite powder; S3 Wet mixing: The mixed base material prepared in step S1 and the nano-composite powder prepared in step S2 are mixed evenly with water to obtain a suspension. Then, latex and polycarboxylate superplasticizer are added and mixed evenly. During the mixing process, the stirring speed is controlled to increase in a stepwise manner. After the dispersion is even, the molding pressure is set to perform molding to obtain a new wall material molded form. S4 Calcination and Forming: The new wall material obtained in step S3 is molded and sintered in stages at varying temperatures. After sintering, it is steam cured to obtain the new wall material. In the S2 two-component compounding step, the organic expanding agent is composed of calcium stearate and azodicarbonamide in a mass ratio of 1:(5~8); the mineral additive is composed of phosphoaluminate and metakaolin in a mass ratio of 1:(1.5~2); the mass ratio of the organic expanding agent to the mineral additive is 1:(5~7); in the S3 wet mixing step, the weight parts of the mixed base material are 70 parts; the weight parts of the nano-composite powder are 12 parts; the weight parts of water are 20 parts; the weight parts of the polycarboxylate superplasticizer are 3 parts; and the weight parts of the latex are 7 parts.

2. The method for preparing a novel wall material based on coal gangue and cement sintering according to claim 1, characterized in that, In the S1 raw material processing step, the particle size of the crushed coal gangue is <15μm; the mass ratio of the coal gangue to cement is 1:(0.1~0.5).

3. The method for preparing a novel wall material based on coal gangue and cement sintering according to claim 1, characterized in that, In the S3 wet mixing step, the stirring speed is divided into four stages: low speed 200 rpm for 3 min; medium speed 450 rpm for 10 min; high speed 800 rpm for 5 min; and low speed 150 rpm for 2 min.

4. The method for preparing a novel wall material based on coal gangue and cement sintering according to claim 1, characterized in that, In the S4 calcination and forming step, the segmented variable temperature sintering is divided into three stages. The first stage is the pre-expansion stage, with a temperature range of 80~160℃, a heating rate of 5℃ / min, and a holding time of 0.5h. The second stage is the crystal reconstruction stage, with a temperature range of 160~650℃, a heating rate of 2℃ / min, and a holding time of 1.5h. The third stage is the strength development stage, with a temperature range of 650~900℃, a heating rate of 1.5℃ / min, and a holding time of 2h.

5. The method for preparing a novel wall material based on coal gangue and cement sintering according to claim 1, characterized in that, In the S4 calcination and forming step, the steam curing temperature is 80℃, the relative humidity is 95%, and the curing time is 15h.

6. A novel wall material prepared by a method for preparing a novel wall material based on coal gangue and cement sintering as described in any one of claims 1 to 5.

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