Coal gangue-graphite tailing-based geopolymer concrete and preparation method thereof

Abstract

The invention discloses coal gangue-graphite tailing-based geopolymer concrete and a preparation method thereof, belongs to the technical field of building materials, and particularly relates to the coal gangue-graphite tailing-based geopolymer concrete and the preparation method thereof. The problems that existing geopolymer concrete is large in drying shrinkage, and coal gangue and graphite tailings pollute the environment and occupy land are solved. The material is prepared from the following components in parts by mass: coal gangue, graphite tailings, fly ash, silica fume, an exciting agent, quartz sand, coarse aggregate and water. The method comprises the following steps: 1, weighing; 2, stage treatment; 3, mixing the materials; and 4, forming and curing the concrete. The two are used for preparing the geopolymer concrete, so that waste resource utilization is realized, environmental pollution and land occupation are reduced, and the cost of raw materials is reduced. A new thought is provided for preparation of geopolymer concrete, and innovative development of a building material technology is promoted.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of building materials, and particularly relates to a coal gangue-graphite tailing-based geopolymer concrete and a preparation method thereof. BACKGROUND

[0002] In the process of development and utilization of coal resources, coal gangue, as a solid waste produced in the process of coal mining and washing, its output shows a surprising growth trend with the vigorous development of the coal industry. A large amount of accumulated coal gangue not only occupies a large amount of valuable land resources, for example, a coal mine with an annual output of ten million tons, the land area occupied by the coal gangue each year can reach tens of hectares, but its potential environmental hazards cannot be underestimated.

[0003] Coal gangue contains a large amount of heavy metals and harmful substances such as sulfur and fluorine. Under the action of natural environment for a long time, these harmful substances will gradually be released into the surrounding environment through processes such as rainwater leaching. With the passage of time, the continuous release of these harmful substances poses a long-term and potential threat to the surrounding ecological environment.

[0004] As of 2022, China's graphite production accounts for about 65% of the world's total production. At the same time, a large amount of graphite tailings are also produced; the accumulation of graphite tailings not only occupies a large amount of land, but also carries chemical substances and residual ore dressing agents, which, under the action of rainwater erosion and natural weathering, can pollute the surrounding soil, water and atmospheric environment; for example, in some graphite tailings accumulation areas, the water quality of the surrounding rivers changes significantly, the suspended solids in the water increase, the chemical oxygen demand increases, etc., causing serious damage to the aquatic ecosystem and affecting the surrounding ecological balance.

[0005] Geopolymer, as a new type of inorganic non-metallic material, has become a research hotspot in the field of materials in recent years due to its high strength, solid waste utilization, green environmental protection and other advantages, and has been widely tried to replace traditional Portland cement. Many scholars have carried out a lot of research work on the comprehensive utilization of coal gangue and graphite tailings and the application of geopolymer. Certain achievements have been made in the performance improvement of single solid waste-based geopolymer and the reaction mechanism; however, the research on the influence of coal gangue and graphite tailings on the mechanical properties of geopolymer concrete is relatively less. In addition, the existing geopolymer concrete also generally has the problem of large drying shrinkage, which seriously affects its application range and service life in actual engineering; therefore, how to effectively utilize coal gangue and graphite tailings to prepare geopolymer concrete with excellent performance, solve the problem of drying shrinkage, and realize the resource utilization of these two solid wastes, not only alleviates the environmental pollution and land occupation problems caused by them, but also meets the performance requirements of concrete materials in engineering, which has become a key problem to be solved in the field of material science and engineering. SUMMARY

[0006] The present application aims to solve the problem of large drying shrinkage of the existing geopolymer concrete, and the environmental pollution and land occupation of coal gangue and graphite tailings, and further provides a coal gangue-graphite tailings based geopolymer concrete and a preparation method thereof.

[0007] A coal gangue-graphite tailings based geopolymer concrete is composed of 280-480 parts by mass of coal gangue, 70-160 parts by mass of graphite tailings, 380-400 parts by mass of fly ash, 160-180 parts by mass of silica fume, 180-200 parts by mass of activator, 430-450 parts by mass of quartz sand, 670-690 parts by mass of coarse aggregate and 20-80 parts by mass of water.

[0008] The preparation method of the above coal gangue-graphite tailings based geopolymer concrete is specifically carried out according to the following steps:

[0009] I. 280-480 parts by mass of coal gangue, 70-160 parts by mass of graphite tailings, 380-400 parts by mass of fly ash, 160-180 parts by mass of silica fume, 180-200 parts by mass of activator, 430-450 parts by mass of quartz sand, 670-690 parts by mass of coarse aggregate and 20-80 parts by mass of water are taken as raw materials according to mass fraction;

[0010] II. The coal gangue and graphite tailings are subjected to grading treatment to obtain coarse coal gangue powder, medium coal gangue powder, fine coal gangue powder, coarse graphite tailings powder, medium graphite tailings powder and fine graphite tailings powder, respectively;

[0011] III. The fly ash, silica fume, quartz sand, coarse aggregate, coarse coal gangue powder and coarse graphite tailings powder are sequentially poured into a cement mixer and dry-mixed for 3-5 min; the medium coal gangue powder and medium graphite tailings powder are added and stirred for another 3-5 min; then the fine coal gangue powder, fine graphite tailings powder, activator and water are added and stirred for another 3-5 min;

[0012] IV. Concrete molding and curing: the mixture is loaded into a plastic triple mold, vibrated for 5 min, covered with plastic film on the surface, placed in a 60℃ air-drying oven for curing for 24 h, then demolded, wrapped with preservative film for curing until the 28d age, to obtain the coal gangue-graphite tailings based geopolymer concrete.

[0013] The present application has the following advantages:

[0014] The present application effectively utilizes the two kinds of wastes, coal gangue and graphite tailings, which are accumulated in large quantities and pollute the environment, reduces the land occupation and environmental pollution of the wastes, realizes the resource utilization of the wastes, and has remarkable environmental benefits. By using the coal gangue and graphite tailings to replace part of the traditional aggregate, the raw material cost is reduced. Meanwhile, the geopolymer concrete has excellent performance, can meet the needs of building engineering, reduces the later maintenance cost, and has good economic benefits. The present application firstly systematically studies the influence of the coal gangue and graphite tailings on the mechanical properties of the geopolymer concrete, provides a new idea and method for the preparation of the geopolymer concrete, and promotes the innovative development of the building material technology. The coal gangue-graphite tailings-based geopolymer concrete prepared by the present application has a 7-day strength of 26.7-41.5 Mpa and a 28-day strength of 33.9-68.4 Mpa. DETAILED DESCRIPTION

[0015] Specific implementation manner one: the coal gangue-graphite tailings-based geopolymer concrete in the present implementation manner is composed of 280-480 parts of coal gangue, 70-160 parts of graphite tailings, 380-400 parts of fly ash, 160-180 parts of silica fume, 180-200 parts of activator, 430-450 parts of quartz sand, 670-690 parts of coarse aggregate, and 20-80 parts of water.

[0016] Fly ash: the first-grade fly ash of Gongyi City Platinum Refractory Material Co., Ltd. is selected. The main chemical components are SiO2, Al2O3, CaO and Fe2O3; SiO2 and Al2O3 can react with the activator to form a three-dimensional network structure with strength.

[0017] Silica fume: purchased from Hebei Jiyang Mine Product Co., Ltd., the main component is amorphous SiO2, and the SiO2 content is as high as 84.69%; the high-activity SiO2 component of the silica fume can fill the pores in the geopolymer, improve the compactness of the concrete, and thus enhance the strength of the concrete.

[0018] Quartz sand: purchased from Hebei Jiyang Mine Product Co., Ltd., and the particle size is 40-70 meshes; the quartz sand serves as fine aggregate, provides a skeleton structure for the concrete, and ensures the stability of the concrete.

[0019] Graphite tailings: produced in a graphite tailings dam in Jixi City, and the fineness modulus is 0.536; the graphite tailings have a certain activity, can participate in part of the reaction in the geopolymer system, and improve the performance of the concrete.

[0020] Coarse aggregate: the continuous gradation gravel with a maximum particle size of 25 mm is used, which provides a main support structure for the concrete and enhances the compressive capacity of the concrete.

[0021] Coal gangue: produced in a coal gangue pile in Jixi City, with a particle size of 5-10 mm; after treatment, the internal active ingredients of the coal gangue can synergize with other raw materials to improve the performance of the geopolymer concrete.

[0022] In this embodiment, both the coal gangue and the graphite tailings contain a certain amount of active ingredients. The coal gangue is rich in silicate minerals, and under the action of an alkaline activator, the internal silicon-oxygen tetrahedron and aluminum-oxygen tetrahedron structures are destroyed, releasing active SiO2 and Al2O3. These active ingredients can react with OH - in the activator to generate geopolymer gels with cementitious properties, such as C-S-H (calcium silicate hydrate) and N-A-S-H (sodium silicate aluminum hydrate) gels, providing early strength to the concrete.

[0023] Although the graphite tailings have a certain degree of inertness, they also contain a small amount of active ingredients, such as SiO2 and trace amounts of metal oxides. At a suitable replacement rate of 25%-50%, their weak pozzolanic activity can be utilized. In the later stages of cement hydration, the active SiO2 in the graphite tailings can undergo a secondary hydration reaction with the cement hydration product Ca (OH)2 to generate more C-S-H gels, further enhancing the structural strength of the concrete. At the same time, trace amounts of metal oxides and other ingredients in the coal gangue and graphite tailings can also regulate the hydration reaction of cement. Certain metal ions (such as Fe 3+ , Mg 2+ , etc.) can promote the early hydration of cement minerals and accelerate strength development; in the later stages, they can stabilize the structure of the hydration products, improving the durability of the concrete.

[0024] At the same time, the particle characteristics of the coal gangue and graphite tailings have a significant impact on the performance of the concrete. After classification and treatment, the coal gangue and graphite tailings particles of different sizes cooperate with each other to form a tight and orderly packing structure. Coarse particles interweave to form the basic skeletal structure of the concrete, enhancing its early stability; medium particles fill the pores formed by coarse particles, reducing internal voids and improving the density of the concrete; fine particles, with their large specific surface area, fully react with the activator, accelerating the formation of geopolymer, and significantly enhancing the late strength and bonding properties of the concrete.

[0025] The particle morphology and grading of the graphite tailings also have unique advantages. The relatively round particle morphology can reduce the frictional resistance between particles in the concrete mixture, improving the workability, compared with the angular quartz powder. Moreover, the fine graphite tailings have a good particle grading at a replacement rate of 25% to 50%, and the particles of different sizes are filled and matched with each other to form a continuous grading system, which is beneficial to improve the fluidity and filling property of the concrete mixture, so that the concrete can be better compacted during pouring to reduce defects and improve the strength.

[0026] Specific embodiment two: The coal gangue-graphite tailings-based geopolymer concrete of the present embodiment is different from that of specific embodiment one in that it is composed of 288 parts of coal gangue, 77 parts of graphite tailings, 382 parts of fly ash, 163 parts of silica fume, 184 parts of activator, 438 parts of quartz sand, 672 parts of coarse aggregate, and 22 parts of water by mass fraction. The other aspects are the same as those of specific embodiment one.

[0027] The mass content of the main components of the sodium carbonate is 7.9% Na2O, 27.9% SiO2, and 64.2% water.

[0028] Specific embodiment three: The present embodiment is different from specific embodiment one in that the activator is composed of NaOH flake and sodium carbonate, and the mass ratio of the NaOH flake to the sodium carbonate is 1:3; the specific gravity of the sodium carbonate is 1.35, and the modulus is 3.3. The other aspects are the same as those of specific embodiment one.

[0029] Specific embodiment four: The present embodiment is different from specific embodiment three in that the activator is prepared by dissolving NaOH flake in water to form an 18 mol / L alkali solution, and then adding sodium carbonate to form an activator solution. The other aspects are the same as those of specific embodiment three.

[0030] Specific embodiment five: The present embodiment is different from specific embodiment one in that the particle size of the quartz sand is 40-70 mesh. The other aspects are the same as those of specific embodiment one.

[0031] Specific embodiment six: The present embodiment is different from specific embodiment one in that the coarse aggregate is a continuously graded gravel with a maximum particle size of 25 mm. The other aspects are the same as those of specific embodiment one.

[0032] Specific embodiment seven: The present embodiment is different from specific embodiment three in that the fineness modulus of the graphite tailings is 0.536. The other aspects are the same as those of specific embodiment three.

[0033] Specific embodiment eight: The preparation method of the coal gangue-graphite tailings-based geopolymer concrete of the present embodiment is specifically performed according to the following steps:

[0034] I. Take 280-480 parts of coal gangue, 70-160 parts of graphite tailings, 380-400 parts of fly ash, 160-180 parts of silica ash, 180-200 parts of activator, 430-450 parts of quartz sand, 670-690 parts of coarse aggregate and 20-80 parts of water as raw materials according to the mass fraction;

[0035] II. The coal gangue and graphite tailings are subjected to grading treatment to obtain coarse coal gangue powder, medium coal gangue powder, fine coal gangue powder, coarse graphite tailings powder, medium graphite tailings powder and fine graphite tailings powder, respectively;

[0036] III. The fly ash, silica ash, quartz sand, coarse aggregate, coarse coal gangue powder and coarse graphite tailings powder are sequentially poured into a cement mixer and dry-mixed for 3-5 min; the medium coal gangue powder and medium graphite tailings powder are then added and mixed for another 3-5 min; and the fine coal gangue powder, fine graphite tailings powder, activator and water are added and mixed for another 3-5 min;

[0037] IV. Concrete molding and curing: the mixture is loaded into a plastic triple-mold, vibrated for 5 min, covered with plastic film on the surface, placed in a 60°C air-drying oven for curing for 24 h, demolded, wrapped with preservative film for curing until the 28d age, to obtain coal gangue-graphite tailings-based geopolymer concrete.

[0038] The present embodiment first adds 80-120 mesh coal gangue coarse particles and 100-150 mesh graphite tailings coarse particles, which interweave with each other to form the basic skeleton structure of the concrete, thereby enhancing the early stability of the concrete; then adds 180-220 mesh coal gangue medium particles and 200-300 mesh graphite tailings medium particles, which fill in the pores formed by the coarse particles, reduce the internal voids and improve the compactness of the concrete; finally adds 300-400 mesh coal gangue fine particles and 300-400 mesh graphite tailings fine particles, which, with the huge specific surface area, fully react with the activator to accelerate the generation of geopolymer and significantly enhance the late strength and bonding performance of the concrete.

[0039] The present embodiment can improve the performance of the geopolymer concrete in multiple dimensions by grading and crushing the coal gangue and graphite tailings and adding them in stages. The multi-level particles fill in each other to form a compact and ordered internal structure, effectively reducing the porosity of the concrete and improving the durability such as impermeability and frost resistance; the particles of different fineness play different roles at different stages, the coarse particles provide support, the fine particles strengthen the reaction, the development of the strength of the concrete is more balanced, and both the early strength and the late strength are optimized; at the same time, this processing method fully taps the potential value of the coal gangue and graphite tailings, improves the utilization rate of industrial solid waste, reduces the production cost, and has both environmental and economic benefits.

[0040] Subsequently, the coal gangue, graphite tailings and auxiliary raw materials after the classification treatment are weighed and proportioned according to a scientific proportioning design. The auxiliary raw materials can be selected according to actual needs, such as silica ash, metakaolin and the like. The performance of the concrete is optimized by adjusting the proportion of each raw material.

[0041] In the use of the activator, a suitable alkaline activator, such as sodium hydroxide, sodium silicate and the like, is selected. The amount of the activator is accurately calculated according to the characteristics of the raw materials, and the activator is prepared into a solution with a certain concentration. Subsequently, the prepared raw materials and the activator solution are added to a stirring device. A reasonable stirring process is adopted. The raw materials are initially mixed uniformly at a low speed, and then further promoted to chemical reaction at a high speed to ensure that each component is fully dispersed and reacted. The stirring time and speed need to be strictly controlled.

[0042] After stirring, the mixture is poured into a mold for molding. The internal air is discharged through vibration, compaction and the like to ensure the compactness of the molding. The molded concrete product needs to be cured in a suitable environment. A standard curing room or a specific curing condition can be selected to control the curing temperature, humidity and time, promote the full reaction of the geopolymer, improve the performance indicators of the concrete, such as strength and durability, and ensure that the final product meets the expected performance requirements.

[0043] Specific embodiment nine: The difference between this embodiment and specific embodiment eight is that the classification treatment of the coal gangue is that the coal gangue is screened and then sent to a crusher for coarse crushing treatment to obtain coal gangue with a particle size of 5-10 mm. The coal gangue after coarse crushing is divided into three parts: one part is ground to 80-120 mesh by a medium-speed grinding machine to obtain coarse coal gangue powder, one part is ground to 180-220 mesh by a high-speed impact grinding machine to obtain medium coal gangue powder, and one part is ground to 300-400 mesh by a superfine grinding machine to obtain fine coal gangue powder. The others are the same as specific embodiment eight.

[0044] Specific embodiment ten: The difference between this embodiment and specific embodiment eight is that the classification treatment of the graphite tailings is that the graphite tailings are screened and then divided into three parts: one part is coarsely ground to 100-150 mesh to obtain coarse graphite tailings powder, one part is ground to 200-300 mesh to obtain medium graphite tailings powder, and one part is ground to 300-400 mesh to obtain fine graphite tailings powder. The others are the same as specific embodiment eight.

[0045] The effect of the present application is verified by the following test:

[0046] The specific raw materials and specifications used in the examples and comparative examples are as follows:

[0047] Comparative example:

[0048] I. Take 3.822 kg fly ash, 1.638 kg silica ash, 5.16 kg quartz sand, 9.6 kg coarse aggregate, 1.364 kg sodium carbonate, 0.227 kg NaOH flake alkali, 0.227 kg water in turn;

[0049] II. Preparation of activator solution: dissolve NaOH flake alkali in appropriate amount of water to prepare 18 mol / L alkali solution; then mix the alkali solution with sodium carbonate, stir uniformly and cool to room temperature for standby;

[0050] III. Stirring of raw materials: pour fly ash, silica ash, quartz sand and coarse aggregate into the cement mixer in turn and dry stir for 5 min; then add the activator solution and 0.227 kg water and continue to stir for 5 min;

[0051] IV. Concrete molding and curing: put the mixture into a plastic triple mold, vibrate for 5 min, cover the surface with plastic film, put into a 60℃ air drying oven for 24 h after demolding; after demolding, wrap it with plastic wrap and cure until 28 d age; test its 7 d strength, 28 d strength and dry density, which are 30.5 MPa, 38.6 MPa and 2.256 kg / m 3 .

[0052] Example 1:

[0053] I. Take 3.822 kg fly ash, 1.638 kg silica ash, 5.16 kg quartz sand, 9.6 kg coarse aggregate, 1.364 kg sodium carbonate, 0.227 kg NaOH flake alkali, 0.774 kg graphite tailings, 2.88 kg coal gangue, 0.227 kg water in turn;

[0054] II. Preparation of activator solution: dissolve NaOH flake alkali in appropriate amount of water to prepare 18 mol / L alkali solution; then mix the alkali solution with sodium carbonate, stir uniformly and cool to room temperature for standby;

[0055] III. Classify the coal gangue and graphite tailings to obtain coarse coal gangue powder, medium coal gangue powder, fine coal gangue powder, coarse graphite tailings powder, medium graphite tailings powder and fine graphite tailings powder respectively; the classification of the coal gangue is to screen the coal gangue and send it to the crusher for coarse crushing to obtain coal gangue with particle size of 5-10 mm in continuous gradation, and the coarse crushed coal gangue is divided into three parts: one part is ground to 80-120 mesh by a medium-speed grinding machine to obtain coarse coal gangue powder, one part is ground to 180-220 mesh by a high-speed impact grinding machine to obtain medium coal gangue powder, and one part is ground to 300-400 mesh by a superfine grinding machine to obtain fine coal gangue powder; the classification of the graphite tailings is to screen the graphite tailings and divide them into three parts: one part is coarsely ground to 100-150 mesh to obtain coarse graphite tailings powder, one part is ground to 200-300 mesh to obtain medium graphite tailings powder, and one part is ground to 300-400 mesh to obtain fine graphite tailings powder;

[0056] Four, the fly ash, silica fume, quartz sand, coarse aggregate, coarse coal gangue powder and coarse graphite tailings powder, pour into the cement mixer dry mixing 3~5min; then add the medium coal gangue powder and medium graphite tailings powder, continue to stir 3~5min; then add the fine coal gangue powder, fine graphite tailings powder, activator and water, continue to stir 3~5min;

[0057] Five, concrete forming and curing: the mixture is loaded into a plastic triple mold, vibrated for 5min, the surface is covered with plastic film, placed in a 60℃ air drying oven for 24h, then demolded, wrapped in plastic wrap after demolding and cured until 28d age, to obtain coal gangue-graphite tailings based geopolymer concrete.

[0058] Test its 7-day strength is 35.6Mpa, 28-day strength is 45.8Mpa, dry density is 2.305kg / m 3 .

[0059] Example 2:

[0060] I, 3.822kg fly ash, 1.638kg silica fume, 5.16kg quartz sand, 9.6kg coarse aggregate, 1.364kg sodium carbonate, 0.227kg NaOH flake alkali, 1.548kg graphite tailings, 4.8kg coal gangue, 0.227kg water are weighed in turn;

[0061] II, preparation of activator solution: dissolve NaOH flake alkali in an appropriate amount of water to prepare 18mol / L alkali solution; then mix the alkali solution with sodium carbonate, stir uniformly and cool to room temperature for standby;

[0062] III, the coal gangue and graphite tailings are classified and treated to obtain coarse coal gangue powder, medium coal gangue powder, fine coal gangue powder, coarse graphite tailings powder, medium graphite tailings powder and fine graphite tailings powder; the classification and treatment of the coal gangue is to screen the coal gangue and send it to the crusher for coarse crushing treatment to obtain 5~10mm particle size continuous gradation coal gangue, the coarse crushed coal gangue is divided into three parts: one part is ground to 80~120mesh by a medium-speed grinding machine to be coarse coal gangue powder, one part is ground to 180~220mesh by a high-speed impact grinding machine to be medium coal gangue powder, and one part is ground to 300~400mesh by a superfine grinding machine to be fine coal gangue powder; the classification and treatment of the graphite tailings is to screen the graphite tailings into three parts: one part is coarsely ground to 100~150mesh to be coarse graphite tailings powder, one part is ground to 200~300mesh to be medium graphite tailings powder, and one part is ground to 300~400mesh to be fine graphite tailings powder;

[0063] Four, the fly ash, silica ash, quartz sand, coarse aggregate, coarse coal gangue powder and coarse graphite tailings powder are poured into the cement mixer in sequence and dry-mixed for 3-5 min; the medium coal gangue powder and medium graphite tailings powder are further added and stirred for 3-5 min; then the fine coal gangue powder, fine graphite tailings powder, activator and water are added and stirred for 3-5 min;

[0064] Five, concrete forming and curing: the mixture is loaded into a plastic triple mold, vibrated for 5 min, covered with plastic film on the surface, placed in a 60℃ air drying oven for curing for 24 h, then demolded, wrapped in plastic wrap for curing until 28d age, to obtain the coal gangue-graphite tailings geopolymer concrete.

[0065] The 7-day strength is 32.3Mpa, the 28-day strength is 42.1Mpa, and the dry density is 2.289kg / m 3 .

[0066] As can be seen from the above examples, the geopolymer concrete prepared by the present application has good mechanical properties and physical properties, and realizes the effective utilization of coal gangue and graphite tailings. With the increase of the replacement rate of coal gangue and graphite tailings, the strength of the geopolymer concrete shows a trend of first increasing and then decreasing. Within a proper replacement rate range, the addition of coal gangue and graphite tailings can effectively improve the strength of the concrete. This is because their active components participate in the formation reaction of geopolymer, improving the microstructure of the concrete. However, when the replacement rate is too high, due to the characteristics of coal gangue and graphite tailings, the internal structure of the concrete may become non-uniform, resulting in a decrease in strength.

[0067] The dry density of the sample is in the range of 2.217-2.379kg / m 3 . The change of dry density is closely related to the replacement rate of coal gangue and graphite tailings and the mix proportion of concrete. Within a reasonable replacement rate, the compactness of the concrete is improved, and the dry density also increases accordingly. This further shows that the geopolymer concrete prepared by the method of the present application has good physical properties.

Claims

1. A coal gangue-graphite tailings base polymer concrete, characterized in that... The concrete is composed of 280-300 parts coal gangue, 70-90 parts graphite tailings, 380-400 parts fly ash, 160-180 parts silica fume, 180-200 parts activator, 430-450 parts quartz sand, 670-690 parts coarse aggregate, and 20-80 parts water by weight.

2. The coal gangue-graphite tailings base polymer concrete according to claim 1, characterized in that... The coal gangue-graphite tailings base polymer concrete is composed of 288 parts coal gangue, 77 parts graphite tailings, 382 parts fly ash, 163 parts silica fume, 184 parts activator, 438 parts quartz sand, 672 parts coarse aggregate and 22 parts water by weight.

3. The coal gangue-graphite tailings base polymer concrete according to claim 1, characterized in that... The activator is composed of NaOH flakes and sodium silicate, wherein the mass ratio of NaOH flakes to sodium silicate is 1:3; the specific gravity of sodium silicate is 1.35 and the modulus is 3.

3.

4. The coal gangue-graphite tailings base polymer concrete according to claim 3, characterized in that... The activator is prepared by dissolving NaOH flakes in water to make an 18 mol / L alkaline solution, and then adding sodium silicate to it to prepare an activator solution.

5. The coal gangue-graphite tailings base polymer concrete according to claim 1, characterized in that... The particle size of the quartz sand is 40-70 mesh.

6. The coal gangue-graphite tailings base polymer concrete according to claim 1, characterized in that... The coarse aggregate is continuously graded crushed stone with a maximum particle size of 25 mm.

7. The coal gangue-graphite tailings base polymer concrete according to claim 1, characterized in that... The fineness modulus of the graphite tailings is 0.

536.

8. The method for preparing a coal gangue-graphite tailings base polymer concrete as described in claim 1, characterized in that... The preparation method of geopolymer concrete based on coal gangue-graphite tailings is carried out according to the following steps:

1. Weigh out 280-480 parts by weight of coal gangue, 70-160 parts by weight of graphite tailings, 380-400 parts by weight of fly ash, 160-180 parts by weight of silica fume, 180-200 parts by weight of activator, 430-450 parts by weight of quartz sand, 670-690 parts by weight of coarse aggregate and 20-80 parts by weight of water as raw materials; 2. The coal gangue and graphite tailings are graded to obtain coarse coal gangue powder, middlings coal gangue powder, fine coal gangue powder, coarse graphite tailings powder, middlings graphite tailings powder and fine graphite tailings powder respectively.

3. In sequence, add fly ash, silica fume, quartz sand, coarse aggregate, coarse coal gangue powder, and coarse graphite tailings powder into a cement mixer and dry mix for 3-5 minutes; then add medium coal gangue powder and medium graphite tailings powder and continue mixing for 3-5 minutes; then add fine coal gangue powder, fine graphite tailings powder, activator, and water, and continue mixing for 3-5 minutes. IV. Concrete Forming and Curing: The mixture is placed into a plastic triple mold, vibrated for 5 minutes, covered with plastic film, and placed in a 60℃ forced-air drying oven for 24 hours. After demolding, it is wrapped with plastic wrap and cured for 28 days to obtain coal gangue-graphite tailings base geopolymer concrete.

9. The method for preparing a coal gangue-graphite tailings base polymer concrete according to claim 1, characterized in that... The grading process of the coal gangue involves screening the coal gangue and then feeding it into a crusher for coarse crushing to obtain coal gangue with a continuous particle size distribution of 5-10mm. The coarsely crushed coal gangue is divided into three parts: one part is ground to 80-120 mesh by a medium-speed grinding mill to obtain coarse coal gangue powder; one part is ground to 180-220 mesh by a high-speed impact grinding mill to obtain medium coal gangue powder; and one part is ground to 300-400 mesh by an ultrafine grinding mill to obtain fine coal gangue powder.

10. The method for preparing a coal gangue-graphite tailings base polymer concrete according to claim 1, characterized in that... The grading treatment of the graphite tailings involves screening the graphite tailings and dividing them into three parts: one part is coarsely ground to 100-150 mesh to obtain coarse graphite tailings powder, one part is ground to 200-300 mesh to obtain medium graphite tailings powder, and one part is ground to 300-400 mesh to obtain fine graphite tailings powder.