Novel wall material based on coal gangue and cement sintering and preparation method thereof

Abstract

The invention relates to the field of preparation of novel wall materials, in particular to a novel wall material based on coal gangue and cement sintering and a preparation method of the novel wall material. According to the innovative preparation method of the coal gangue cement-based composite material, the novel expanding agent and the mineral additive are introduced into the traditional cement-based composite material, so that the limitation of the prior art is broken through, and the wall material with higher comprehensive performance and lower cost is obtained. The material is not only suitable for the building industry, but also can be widely applied to other fields, such as environmental protection, infrastructure construction and the like.

Description

Technical Field

[0001] The present invention relates to the field of preparation of new wall materials, and in particular to a new wall material based on sintering of coal gangue and cement and a preparation method thereof. Background Art

[0002] With the continuous advancement of industrialization and urbanization, the demand for building materials is growing. Cement-based composites, a common material in construction projects, have been the focus of research on improving their performance and reducing their costs. Traditional cement-based materials often have limitations in terms of thermal insulation, sound insulation, seismic resistance, and corrosion resistance. Coal gangue, as an industrial byproduct, has great application potential. However, traditional coal gangue building materials face technical bottlenecks such as uneven pore structure and difficulty in synergistically improving mechanical and thermal insulation properties, which have hindered the full optimization of their physical properties and structure. While existing technologies have attempted to introduce single expansion agents or mineral admixtures, they have the following shortcomings: physical foaming agents lead to uneven pore distribution and significant degradation of mechanical properties; mineral additives have a limited effect, unable to simultaneously improve thermal insulation and durability; and there is a lack of in-depth chemical control mechanisms for the active components of coal gangue. Therefore, exploring new preparation methods for coal gangue and cement-based composites, especially improving their performance through the introduction of expansion agents and mineral additives, is a major challenge in current technology. Summary of the Invention

[0003] To address the above-mentioned existing technical problems, the present invention aims to provide a novel wall material based on coal gangue and cement sintering, and its preparation method. This novel wall material is achieved by introducing a novel expansion agent and mineral additives into a traditional cement-based composite material. 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 also has broad applications in other fields, such as environmental protection and infrastructure construction.

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

[0005] S1 Raw material processing: crush the coal gangue, calcine it under nitrogen atmosphere, and then mix it with cement to obtain a mixed base material;

[0006] S2 two-component compounding: ball-milling and blending the organic expander and the mineral additive to form a nano-scale composite powder;

[0007] S3 wet mixing: adding water to the mixed base prepared in step S1 and the nano-scale composite powder prepared in step S2 and mixing them evenly to obtain a suspension; then adding the latex and the polycarboxylate water reducer and mixing them evenly; during the mixing process, controlling the stirring speed to increase in a stepwise manner; after the dispersion is evenly distributed, setting the molding pressure and performing compression molding to obtain a molded type of the new wall material;

[0008] S4 calcination molding: the new wall material obtained in step S3 is molded and sintered in stages at variable temperatures, and steam cured after sintering to obtain the new wall material.

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

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

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

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

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

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

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

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

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

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention provides a new wall material based on coal gangue and cement sintering and a preparation method thereof, which has the following beneficial effects:

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

[0021] (2) The formation of the 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 expansion agent, which enhances its toughness and elasticity and significantly improves its seismic resistance.

[0023] (4) The synergistic effect of mineral additives improves the material's microstructure and its resistance to acid and alkali corrosion. The durability of the material is much higher than that of traditional cement materials.

[0024] (5) The present invention proposes for the first time the synergistic mechanism of the azodicarbonamide-calcium stearate composite expansion system (organic expansion agent) and the phosphate aluminate-metakaolin mineral additive; constructs a three-stage reaction path of "chemical expansion-crystal reconstruction-interface strengthening" to achieve precise control of the material microstructure; and realizes the unity of light weight and high strength.

[0025] (6) Develop a segmented variable temperature sintering process to ensure the temporal and spatial matching of reaction kinetics and thermodynamic processes.

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

[0027] The following examples are provided for a better understanding of the present invention and are not intended to limit the best mode of implementation. They do not limit the content and scope of protection of the present invention. Any product identical or similar to the present invention obtained by anyone under the guidance of the present invention or by combining the features of the present invention with other prior arts shall fall within the scope of protection of the present invention.

[0028] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in this field can be used. If the manufacturer of the reagents or instruments is not specified, they are all commercially available conventional reagents.

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

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

[0031] S2 two-component compounding: adding an organic expander and a mineral additive in a mass ratio of 1:5 to a mixer for ball milling and blending to form a nano-scale composite powder; wherein the organic expander is composed of calcium stearate and azodicarbonamide in a mass ratio of 1:5; the mineral additive is composed of phosphate aluminate and metakaolin in a mass ratio of 1:1.5.

[0032] S3 wet mixing:

[0033] 70 parts by weight of the mixed base, 12 parts by weight of the nanocomposite powder, and 20 parts by weight of water are mixed to form a suspension. Then, 3 parts by weight of a polycarboxylate superplasticizer and 7 parts by weight of a latex are added to the suspension and mixed evenly. During the mixing process, the stirring speed is increased in a stepwise 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, the molding pressure is increased and compression molding is performed to obtain a molded part of the new wall material.

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

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

[0036] S1 Raw material processing: Grind the coal gangue to a particle size of <15μm; then calcine it in a nitrogen atmosphere, control the calcination temperature to 820℃, and the calcination time to 1.4h. After the coal gangue is calcined and modified, mix it with cement at a mass ratio of 1:0.2 to obtain a mixed base material.

[0037] S2 two-component compounding: adding an organic expander and a mineral additive in a mass ratio of 1:5.5 to a mixer for ball milling and blending to form a nano-scale composite powder; wherein the organic expander is composed of calcium stearate and azodicarbonamide in a mass ratio of 1:5; the mineral additive is composed of phosphate aluminate and metakaolin in a mass ratio of 1:1.5.

[0038] S3 wet mixing:

[0039] 70 parts by weight of the mixed base, 12 parts by weight of the nanocomposite powder, and 20 parts by weight of water are mixed to form a suspension. Then, 3 parts by weight of a polycarboxylate superplasticizer and 7 parts by weight of a latex are added to the suspension and mixed evenly. During the mixing process, the stirring speed is increased in a stepwise 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, the molding pressure is increased and compression molding is performed to obtain a molded part of the new wall material.

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

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

[0042] S1 Raw material processing: Crush the coal gangue to a particle size of <15μm; then calcine it under a nitrogen atmosphere, control the calcination temperature to 840℃, and the calcination time to 1.6h. After the coal gangue is calcined and modified, mix it with cement at a mass ratio of 1:0.3 to obtain a mixed base material.

[0043] S2 two-component compounding: adding an organic expander and a mineral additive in a mass ratio of 1:6 to a mixer for ball milling and blending to form a nano-scale composite powder; wherein the organic expander is composed of calcium stearate and azodicarbonamide in a mass ratio of 1:5; the mineral additive is composed of phosphate aluminate and metakaolin in a mass ratio of 1:1.5.

[0044] S3 wet mixing:

[0045] 70 parts by weight of the mixed base, 12 parts by weight of the nanocomposite powder, and 20 parts by weight of water are mixed to form a suspension. Then, 3 parts by weight of a polycarboxylate superplasticizer and 7 parts by weight of a latex are added to the suspension and mixed evenly. During the mixing process, the stirring speed is increased in a stepwise 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, the molding pressure is increased and compression molding is performed to obtain a molded part of the new wall material.

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

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

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

[0049] S2 two-component compounding: adding an organic expander and a mineral additive in a mass ratio of 1:6.5 to a mixer for ball milling and blending to form a nano-scale composite powder; wherein the organic expander is composed of calcium stearate and azodicarbonamide in a mass ratio of 1:5; the mineral additive is composed of phosphate aluminate and metakaolin in a mass ratio of 1:1.5.

[0050] S3 wet mixing:

[0051] 70 parts by weight of the mixed base, 12 parts by weight of the nanocomposite powder, and 20 parts by weight of water are mixed to form a suspension. Then, 3 parts by weight of a polycarboxylate superplasticizer and 7 parts by weight of a latex are added to the suspension and mixed evenly. During the mixing process, the stirring speed is increased in a stepwise 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, the molding pressure is increased and compression molding is performed to obtain a molded part of the new wall material.

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

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

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

[0055] S2 two-component compounding: adding an organic expander and a mineral additive in a mass ratio of 1:7 to a mixer for ball milling and blending to form a nano-scale composite powder; wherein the organic expander is composed of calcium stearate and azodicarbonamide in a mass ratio of 1:5; the mineral additive is composed of phosphate aluminate and metakaolin in a mass ratio of 1:1.5.

[0056] S3 wet mixing:

[0057] 70 parts by weight of the mixed base, 12 parts by weight of the nanocomposite powder, and 20 parts by weight of water are mixed to form a suspension. Then, 3 parts by weight of a polycarboxylate superplasticizer and 7 parts by weight of a latex are added to the suspension and mixed evenly. During the mixing process, the stirring speed is increased in a stepwise 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, the molding pressure is increased and compression molding is performed to obtain a molded part of the new wall material.

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

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

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

[0061] S2 two-component compounding: adding an organic expander to a mixer for ball milling and blending to form a nano-scale powder; wherein the organic expander is composed of calcium stearate and azodicarbonamide in a mass ratio of 1:5.

[0062] S3 wet mixing:

[0063] 70 parts by weight of the mixed base, 12 parts by weight of the nanocomposite powder, and 20 parts by weight of water are mixed to form a suspension. Then, 3 parts by weight of a polycarboxylate superplasticizer and 7 parts by weight of a latex are added to the suspension and mixed evenly. During the mixing process, the stirring speed is increased in a stepwise 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, the molding pressure is increased and compression molding is performed to obtain a molded part of the new wall material.

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

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

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

[0067] S2 two-component compounding: adding the mineral additive into the mixer for ball milling and blending to form nano-scale powder; wherein the mineral additive is composed of phosphate aluminate and metakaolin in a mass ratio of 1:1.5.

[0068] S3 wet mixing:

[0069] 70 parts by weight of the mixed base, 12 parts by weight of the nanocomposite powder, and 20 parts by weight of water are mixed to form a suspension. Then, 3 parts by weight of a polycarboxylate superplasticizer and 7 parts by weight of a latex are added to the suspension and mixed evenly. During the mixing process, the stirring speed is increased in a stepwise 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, the molding pressure is increased and compression molding is performed to obtain a molded part of the new wall material.

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

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

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

[0073] S2 two-component compounding: adding an organic expander and a mineral additive in a mass ratio of 1:7 to a mixer for ball milling and blending to form a nano-scale composite powder; wherein the organic expander is composed of calcium stearate and azodicarbonamide in a mass ratio of 1:5; the mineral additive is composed of phosphate aluminate and metakaolin in a mass ratio of 1:1.5.

[0074] S3 wet mixing:

[0075] 70 parts by weight of a mixed base, 12 parts by weight of a nano-scale composite powder, and 20 parts by weight of water are uniformly mixed to obtain a suspension, and then 3 parts by weight of a polycarboxylate water reducer and 7 parts by weight of a latex are added to the suspension and mixed uniformly. During the mixing process, the stirring speed is controlled to be 500 rpm and the stirring is carried out for 20 minutes. After uniform dispersion, the molding pressure is set and compression molding is carried out to obtain a molded type of a new wall material.

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

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

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

[0079] S2 two-component compounding: adding an organic expander and a mineral additive in a mass ratio of 1:7 to a mixer for ball milling and blending to form a nano-scale composite powder; wherein the organic expander is composed of calcium stearate and azodicarbonamide in a mass ratio of 1:5; the mineral additive is composed of phosphate aluminate and metakaolin in a mass ratio of 1:1.5.

[0080] S3 wet mixing:

[0081] 70 parts by weight of the mixed base, 12 parts by weight of the nanocomposite powder, and 20 parts by weight of water are mixed to form a suspension. Then, 3 parts by weight of a polycarboxylate superplasticizer and 7 parts by weight of a latex are added to the suspension and mixed evenly. During the mixing process, the stirring speed is increased in a stepwise 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, the molding pressure is increased and compression molding is performed to obtain a molded part of the new wall material.

[0082] S4 calcination molding: the new wall material mold obtained in step S3 is sintered at a temperature range of 650-900°C and a heating rate of 5°C / min. After sintering, steam curing is performed at a temperature of 80°C, a relative humidity of 95%, and a curing time of 15 hours to finally obtain a new wall material.

[0083] The new wall materials prepared in Examples 1 to 9 were subjected to performance tests (thermal insulation performance, sound insulation performance, seismic performance and corrosion resistance), and the test results are shown in the following table:

[0084]

[0085] It can be seen from the data in the above table that the data of Examples 1 to 5 show that with the increase of the calcination temperature of coal gangue (from 800°C to 880°C), the extension of the calcination time (from 1.2h to 2.0h) and the increase of the cement ratio in the mixture of coal gangue and cement (from 1:0.1 to 1:0.5), the various performances of the new wall material show a significant improvement trend; in terms of thermal insulation performance, the thermal conductivity coefficient gradually decreases, indicating that the thermal insulation performance of the material is improving; in terms of sound insulation performance, the sound insulation volume gradually increases, indicating that the material's ability to block sound is increasing; in terms of seismic performance, the ductility ratio gradually increases, which means that the deformation ability and energy consumption capacity of the material under earthquake action are increasing; in terms of corrosion resistance, the mass loss rate gradually decreases, indicating that the durability of the material in a corrosive environment is improving.

[0086] Example 6 was prepared without the addition of a mineral additive, while Example 7 was prepared without the addition of an organic expansion agent. Compared to Example 5, the omission of the mineral additive in Example 6 resulted in a decrease in all performance characteristics of the new wall material. The omission of the organic expansion agent significantly impacted the performance of the new wall material. This is because azodicarbonamide decomposes to produce nitrogen and carbon dioxide gases, which form micropores in the material. Calcium stearate reduces interfacial tension and modulates the pore morphology to a spherical closed-cell structure. Aluminophosphate provides phosphate and tetrahydroxyaluminate groups, promoting the transformation of the CSH gel to the tobermorite crystal form. Metakaolin strengthens the interfacial transition zone. The micropores created by the organic expansion agent provide nucleation sites for the crystal remodeling of the mineral additive. The hydration products of the mineral additive fill the surface defects of the pores, forming a "hard and flexible" pore wall structure, significantly improving the compressive strength of the resulting new wall material.

[0087] Example 8, in which step-by-step stirring was omitted, had a certain impact on the performance of the new wall material compared to Example 5. This is because step-by-step stirring gradually improves the mixing uniformity of the materials, helps form a denser microstructure, reduces porosity and defects, and thus improves the thermal insulation, sound insulation, seismic resistance, and corrosion resistance of the new wall material.

[0088] Example 9, which does not undergo staged calcination, shows a decrease in all performance characteristics of the new wall material compared to Example 5. This is because staged calcination allows for the regulation of the pore structure. The graded pore design reduces the thermal conductivity of the sintered porous brick while maintaining a porosity of over 80%, achieving both thermal insulation and structural stability. Staged calcination promotes the solid solution of impurity oxides, forming substitutional or interstitial solid solutions and enhancing grain boundary bonding. It also offers energy-saving and environmental benefits.

[0089] Example 10: The mass ratio of calcium stearate and azodicarbonamide in the organic expander was screened; the screening results are shown in the following table:

[0090]

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

[0092] Example 11: The mass ratio of aluminophosphate and metakaolin in the mineral additives was screened; the screening results are shown in the following table:

[0093]

[0094] The data in the table above shows that the new wall material achieves optimal overall performance when the mass ratio of aluminophosphate to metakaolin is 1:1.7. At this point, the material exhibits excellent thermal insulation, sound insulation, seismic resistance, and corrosion resistance. While an appropriate mass ratio of aluminophosphate to metakaolin can effectively improve material performance, either excess or insufficient amounts can lead to negative effects. Therefore, in practical applications, the mass ratio of aluminophosphate to metakaolin should be strictly controlled to ensure the optimal overall performance of the new wall material.

[0095] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for preparing a new wall material based on coal gangue and cement sintering, characterized in that: The following steps are involved: S1 Raw material processing: crush the coal gangue, calcine it under nitrogen atmosphere, and then mix it with cement to obtain a mixed base material; S2 two-component compounding: ball-milling and blending the organic expander and the mineral additive to form a nano-scale composite powder; S3 wet mixing: adding water to the mixed base prepared in step S1 and the nano-scale composite powder prepared in step S2 and mixing them evenly to obtain a suspension; then adding the latex and the polycarboxylate water reducer and mixing them evenly; during the mixing process, controlling the stirring speed to increase in a stepwise manner; after the dispersion is evenly distributed, setting the molding pressure and performing compression molding to obtain a molded type of the new wall material; S4 calcination molding: the new wall material obtained in step S3 is molded and sintered in stages at variable temperatures, and steam cured after sintering to obtain the new wall material.

2. The method for preparing a new 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 less than 15 μm; the mass ratio of the coal gangue to cement is 1: (0.1-0.5).

3. The method for preparing a new wall material based on coal gangue and cement sintering according to claim 1, characterized in that: In the S2 two-component compounding step, the organic expander is composed of calcium stearate and azodicarbonamide in a mass ratio of 1:(5-8).

4. The method for preparing a new wall material based on coal gangue and cement sintering according to claim 1, characterized in that: In the S2 two-component compounding step, the mineral additive is composed of aluminophosphate and metakaolin in a mass ratio of 1:(1.5-2).

5. The method for preparing a new wall material based on coal gangue and cement sintering according to claim 1, characterized in that: In the two-component compounding step S2, the mass ratio of the organic expander to the mineral additive is 1:(5-7).

6. The method for preparing a new wall material based on coal gangue and cement sintering according to claim 1, characterized in that: In the S3 wet mixing step, the weight of the mixed base is 70 parts; the weight of the nano-composite powder is 12 parts; the weight of water is 20 parts; the weight of the polycarboxylate water reducer is 3 parts; and the weight of the latex is 7 parts.

7. The method for preparing a new 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 stirring for 3 minutes; medium speed 450 rpm stirring for 10 minutes; high speed 800 rpm stirring for 5 minutes; low speed 150 rpm stirring for 2 minutes.

8. The method for preparing a new wall material based on coal gangue and cement sintering according to claim 1, characterized in that: In the S4 calcination and molding 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°C, a heating rate of 5°C / min, and a holding time of 0.5h; the second stage is the crystal reconstruction stage, with a temperature range of 160-650°C, a heating rate of 2°C / min, and a holding time of 1.5h; the third stage is the strength development stage, with a temperature range of 650-900°C, a heating rate of 1.5°C / min, and a holding time of 2h.

9. The method for preparing a new wall material based on coal gangue and cement sintering according to claim 1, characterized in that: In the S4 calcination and molding step, the steam curing temperature is 80° C., the relative humidity is 95%, and the curing time is 15 hours.

10. A new wall material prepared by the method for preparing a new wall material based on sintering coal gangue and cement according to any one of claims 1 to 9.

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