Geopolymer cement based on coal gangue activation reaction as well as preparation method and application of geopolymer cement

Abstract

The invention discloses geopolymer cement based on coal gangue activation reaction as well as a preparation method and application thereof, and relates to the technical field of building materials. The invention relates to a coal gangue concrete, which is prepared from the following raw materials in percentage by mass: 50 to 70 percent of activated coal gangue powder, 5 to 15 percent of alkali activator, 10 to 30 percent of auxiliary cementing material and water, wherein the water accounts for 30 to 40 percent of the total mass of the activated coal gangue powder, the alkali activator and the auxiliary cementing material. Through a composite activation process of medium-temperature calcination decarburization and superfine grinding, the activity of silicon-aluminum components in the coal gangue is effectively excited, the reaction efficiency is remarkably improved, the mixing amount of the coal gangue reaches 50%-70%, the resource utilization rate of solid waste is greatly increased, and efficient activation and resource utilization of the coal gangue are achieved. By adopting the methyl sodium silicate and sodium silicate composite activator, the reaction rate and the product structure are regulated and controlled, and the workability and the setting and hardening behaviors of slurry are improved, so that the obtained geopolymer cement has relatively high early and later strength and excellent durability.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of building materials, and in particular relates to a geopolymer cement based on coal gangue activation reaction and a preparation method and application thereof. BACKGROUND

[0002] Coal gangue is the main solid waste in the process of coal mining and washing, and its large accumulation not only occupies land resources, but also may release harmful substances due to weathering, leaching and other processes, causing long-term pollution to soil, water and ecological environment. Traditional cement production process relies on limestone calcination, which has high energy consumption and large carbon emissions, and is contrary to the current green and low-carbon development concept. As a new type of aluminosilicate cementitious material, geopolymer cement forms a three-dimensional network structure through alkali activation reaction, and has excellent properties such as early strength, corrosion resistance, low shrinkage and low carbon environmental protection, and is considered as one of the ideal substitutes for traditional cement.

[0003] However, in the prior art, the application of coal gangue in geopolymer still faces the following key problems: 1. Insufficient activity excitation: the silicon aluminum components in the original coal gangue have high crystallinity and poor reactivity, and a single activation method cannot effectively release the cementitious potential thereof; 2. Residual carbon interferes with the reaction: coal gangue usually contains 15% to 17% of residual carbon, which affects the uniformity of the cementitious system and the structural stability of the final product; 3. Using a single alkali activator may lead to difficulties in controlling the reaction process, and problems such as unreasonable setting time and unstable strength development may occur. Therefore, it is urgent to develop a geopolymer cement preparation technology that can efficiently activate coal gangue, optimize the reaction system, and realize the large-scale high-value utilization thereof.

[0004] Therefore, we propose a geopolymer cement based on coal gangue activation reaction and a preparation method and application thereof to solve the problems mentioned above.

[0005] The above information disclosed in the background section is only intended to increase the understanding of the background of the present application, and therefore, it can include information known by those of ordinary skill in the art. SUMMARY

[0006] The purpose of the present application is to provide a geopolymer cement based on coal gangue activation reaction and a preparation method and application thereof to overcome the problems of low activity of coal gangue, serious carbon interference and insufficient alkali activation efficiency in the prior art.

[0007] In order to achieve the above-mentioned purpose, the present application provides the following technical scheme: a geopolymer cement based on coal gangue activation reaction, which is composed of the following raw materials in mass percentage: activated coal gangue powder 50% to 70%, alkali activator 5% to 15%, auxiliary cementitious material 10% to 30%, and water, wherein the water is 30% to 40% of the total mass of the activated coal gangue powder, the alkali activator and the auxiliary cementitious material.

[0008] Preferably, the activated coal gangue powder is calcined at 500-800 DEG C by a rotary calcining device to remove carbon and has a carbon content of 15-17%, and is treated by a superfine airflow grinding machine to have a particle size of less than or equal to 20 microns and a specific surface area of greater than or equal to 500 m2 / kg.

[0009] Preferably, the alkali activator comprises sodium methyl silicate and sodium silicate, the sodium methyl silicate accounts for 30-50% of the total mass of the alkali activator, the purity of the sodium methyl silicate is greater than or equal to 98%, and the modulus of the sodium silicate is 1.5-3.5.

[0010] Preferably, the auxiliary cementitious material comprises at least one of slag powder and fly ash, the slag powder has a specific surface area of greater than or equal to 400 m2 / kg, and the fly ash is grade I or grade II fly ash.

[0011] The application further provides a preparation method of the geopolymer cement based on the activation reaction of coal gangue, comprising the following steps:

[0012] Step 1: coal gangue pretreatment: coal gangue with a carbon content of 15-17% is crushed to have a particle size of less than or equal to 5 mm, is calcined at 500-800 DEG C in a rotary calcining device for 1-2 hours to remove carbon and activate silicon and aluminum components;

[0013] Step 2: superfine grinding: the calcined coal gangue is put into a superfine airflow grinding machine to have a particle size of less than or equal to 20 microns and a specific surface area of greater than or equal to 500 m2 / kg, thereby obtaining activated coal gangue powder;

[0014] Step 3: mixing and activation: the activated coal gangue powder, the auxiliary cementitious material and the alkali activator are uniformly dry mixed, water is added and stirred to form a slurry, the water-binder ratio is 0.30-0.40, the stirring time is greater than or equal to 3 minutes, and after the slurry is shaped, it is cured at 20-40 DEG C for 24-48 hours to obtain early strength.

[0015] Preferably, in the step 1, the calcination stage adopts oxygen enrichment combustion technology, oxygen-enriched air with an oxygen concentration of 25-30% is introduced to make the carbon in the coal gangue burn efficiently.

[0016] Preferably, in the step 2, the superfine grinding stage adopts a three-ring medium-speed superfine grinding machine, and the grinding temperature is controlled to be less than or equal to 60 DEG C to prevent decomposition of active components.

[0017] Preferably, in the step 3, the dry mixing time is 1-2 minutes, and the stirring speed is 100-200 rpm to ensure uniform mixing.

[0018] The application further provides application of the geopolymer cement based on the activation reaction of coal gangue as described above in road base / surface layer materials, light aggregate concrete preparation, soil solidifying agents and water treatment adsorption materials.

[0019] Preferably, when the geopolymeric cement is used for road base / surface layer material, the geopolymeric cement is mixed with aggregate at a mass ratio of 1:3 to 1:5, and the compaction degree is greater than or equal to 95%; when the geopolymeric cement is used for light aggregate concrete preparation, the geopolymeric cement is mixed with light aggregate at a mass ratio of 1:1 to 1:3, and the dry density is less than or equal to 1800 kg / m³; when the geopolymeric cement is used for soil solidification agent, the addition amount is 5% to 15% of the mass of the soil, and the unconfined compressive strength of the solidified soil is greater than or equal to 2 MPa; when the geopolymeric cement is used for water treatment adsorption material, the geopolymeric cement is made into granular adsorbent, the specific surface area is greater than or equal to 600 m² / kg, and the adsorption rate of heavy metal ions is greater than or equal to 90%.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] 1. The present application effectively activates the silicon and aluminum components in coal gangue by a composite activation process of medium-temperature calcination and decarburization and superfine grinding, significantly improves the reaction efficiency, and enables the coal gangue content to reach 50% to 70%, thereby greatly improving the resource utilization rate of solid waste and realizing efficient activation and resource utilization of coal gangue.

[0022] 2. The present application uses a composite activator of sodium methyl silicate and sodium silicate to control the reaction rate and product structure, improve the workability and setting and hardening behavior of the slurry, and enable the obtained geopolymeric cement to have high early and late strength and excellent durability.

[0023] 3. The present application uses industrial solid waste as the main raw material, significantly reduces the dependence on traditional cement clinker, and has much lower carbon emissions and energy consumption than ordinary Portland cement in the production process, thereby conforming to the development direction of environment-friendly and green building materials.

[0024] 4. The product of the present application can not only be used for structural materials such as road engineering and light aggregate concrete, but also be used as a soil solidification agent and a water treatment adsorption material, thereby realizing one material with multiple uses and broadening the application field of geopolymeric materials. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments described in the present application, and other drawings can also be obtained by those skilled in the art based on these drawings.

[0026] Figure 1 The present application is a preparation flowchart. DETAILED DESCRIPTION

[0027] In order for those skilled in the art to better understand the technical solutions of the present application, the present application will be further described in detail below with reference to the drawings. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0028] A geopolymer cement based on coal gangue activation reaction, which is composed of the following raw materials in percentage by mass: activated coal gangue powder 50-70%, alkali activator 5-15%, auxiliary cementitious material 10-30%, and water, which is 30-40% of the total mass of the activated coal gangue powder, alkali activator and auxiliary cementitious material.

[0029] Specifically, the activated coal gangue powder is decarburized by calcination at 500-800℃ through a rotary calcination device, with carbon content of 15-17%, and is processed by a superfine jet mill to a particle size of ≤20μm and a specific surface area of ≥500 m² / kg.

[0030] Specifically, the alkali activator includes sodium methyl silicate and sodium silicate, with sodium methyl silicate accounting for 30-50% of the total mass of the alkali activator, the purity of sodium methyl silicate being ≥98%, and the modulus of sodium silicate being 1.5-3.5.

[0031] Specifically, the auxiliary cementitious material includes at least one of slag powder and fly ash.

[0032] A preparation method of a geopolymer cement based on coal gangue activation reaction, characterized in that it comprises the following steps:

[0033] Step 1, coal gangue pretreatment: coal gangue with carbon content of 15-17% is crushed to a particle size of ≤5mm, and is calcined at 500-800℃ for 1-2 hours in a rotary calcination device to decarburize and activate the silicon-aluminum components;

[0034] Specifically, the oxygen-enhanced combustion technology is used in the calcination stage, and oxygen-enriched air with oxygen concentration of 25-30% is introduced to make the carbon in coal gangue burn efficiently.

[0035] Step 2, superfine grinding: the calcined coal gangue is put into a superfine jet mill to grind to a particle size of ≤20μm and a specific surface area of ≥500 m² / kg, to obtain activated coal gangue powder;

[0036] Specifically, the three-ring medium-speed superfine grinding mill is used in the superfine grinding stage, and the grinding temperature is controlled to be ≤60℃ to prevent the decomposition of active components.

[0037] Step 3, mixed excitation: the activated coal gangue powder, auxiliary cementitious material and alkali activator are dry mixed uniformly, water is added for stirring to form a slurry, the water-binder ratio is 0.30-0.40, the stirring time is greater than or equal to 3 minutes, and after the slurry is formed, the slurry is cured at 20-40℃ for 24-48 hours to obtain early strength.

[0038] Specifically, the dry mixing time is 1-2 minutes, and the stirring speed is 100-200 rpm to ensure uniform mixing.

[0039] The application of the above-mentioned geopolymer cement based on coal gangue activation reaction in road base / floor materials, light aggregate concrete preparation, soil solidification agent and water treatment adsorption material.

[0040] When the above-mentioned geopolymer cement is used in road base / floor materials, the aggregate is mixed at a mass ratio of 1:3-1:5, and the compaction degree is greater than or equal to 95%;

[0041] When the above-mentioned geopolymer cement is used in light aggregate concrete preparation, the light aggregate is mixed at a mass ratio of 1:1-1:3, and the dry density is less than or equal to 1800 kg / m³;

[0042] When the above-mentioned geopolymer cement is used in soil solidification agent, the addition amount is 5%-15% of the mass of the soil, and the unconfined compressive strength of the solidified soil is greater than or equal to 2MPa;

[0043] When the above-mentioned geopolymer cement is used in water treatment adsorption material, the granular adsorbent is prepared, the specific surface area is greater than or equal to 600m² / kg, and the adsorption rate of heavy metal ions is greater than or equal to 90%.

[0044] In order to verify the comprehensive performance of the geopolymer cement based on coal gangue activation reaction, comparative experiments are carried out, and the mechanical properties, environmental benefits and durability are evaluated.

[0045] Experimental group

[0046] The following raw materials are prepared:

[0047] 60% activated coal gangue powder: calcination condition: 600℃, 1.5 hours; particle size after grinding is less than or equal to 20μm, specific surface area is greater than or equal to 500m² / kg;

[0048] 10% alkali activator: 40% of which is sodium methyl silicate, and the purity is greater than or equal to 98%, and the modulus of sodium silicate is 2.5;

[0049] 30% auxiliary cementitious material: 15% of which is slag powder and 15% of which is fly ash, the specific surface area of the slag powder is greater than or equal to 400m² / kg, and the fly ash is grade I;

[0050] Water: 35% of the total mass of the above solids.

[0051] Step 1, coal gangue pretreatment: after crushing, calcine in rotary calcination equipment at 600℃ for 1.5 hours, and pass in oxygen-rich air with oxygen concentration of 28%.

[0052] Step 2, superfine grinding: use three-ring medium-speed superfine grinding machine, control temperature ≤ 60℃, and grind to particle size ≤ 20μm.

[0053] Step 3, mixed activation: dry mix for 1.5 minutes, stirring speed 150 rpm, add water and stir for 3 minutes, water-binder ratio 0.35. After the slurry is formed, it is cured at 25℃ for 48 hours, and then moved to a standard curing room (20℃, 95% humidity) until the test age.

[0054] Control group 1

[0055] Prepare the following raw materials:

[0056] Ordinary Portland cement: 100%;

[0057] Water: water-cement ratio 0.4;

[0058] Aggregate: standard ISO sand, cement:sand = 1:3;

[0059] According to GB / T 17671-1999 standard, mix cement, standard sand and water, stir and then form, and standard cure at 20℃, 95% humidity.

[0060] Control group 2

[0061] Prepare the following raw materials:

[0062] 60% unactivated coal gangue powder: same source coal gangue as the experimental group, only crushed to particle size ≤ 5mm, not calcined;

[0063] 10% alkali activator: same as the experimental group;

[0064] 30% auxiliary cementitious material: same as the experimental group;

[0065] Water: 35% of the total mass of the above solids.

[0066] Except that the coal gangue is not calcined, the other steps are the same as the experimental group, i.e. directly use the unactivated coal gangue powder after crushing.

[0067] 1. Mechanical property test

[0068] Prepare 40mm×40mm×160mm prismatic specimens, 9 for each group. The test time points are 3 days, 7 days and 28 days. The compressive strength and flexural strength are tested according to GB / T 17671-1999 "Cement mortar strength test method", and the equipment uses a universal testing machine.

[0069] The experimental results are shown in the following table.

[0070] Group 3-day compressive strength 7-day compressive strength 28-day compressive strength 28-day flexural strength Experimental group 18.5 MPa 32.6 MPa 48.2 MPa 7.4 MPa Control group 1 20.8 MPa 34.1 MPa 49.5 MPa 8.1 MPa Control group 2 7.2 MPa 13.5 MPa 25.8 MPa 4.3 MPa

[0071] From the above, the 28-day compressive strength of the experimental group reached 48.2 MPa, which was comparable to that of the control group 1 (49.5 MPa) and significantly higher than that of the control group 2 (25.8 MPa). The early strength of the experimental group (18.5 MPa) was slightly lower than that of the control group 1 (20.8 MPa), but the gap narrowed after 7 days. The control group 2 had significantly lower strength, demonstrating the effect of coal gangue activation.

[0072] 2. Environmental benefits

[0073] Based on life cycle assessment (LCA), the CO2 emissions per ton of cement produced were calculated, including raw material processing, calcination, grinding, and other energy consumption.

[0074] The total energy consumption (kWh) per ton of cement produced was calculated, including crushing, calcination, grinding, and other processes.

[0075] The experimental results are shown in the table below.

[0076] Group Carbon emissions (kg CO2 / ton of cement) Energy consumption (kWh / ton of cement) Waste utilization rate (%) Experimental group 185 92 60 Control group 1 850 135 0 Control group 2 120 65 60

[0077] From the above, the carbon emissions of the experimental group were 185 kg CO2 / ton of cement, and the energy consumption was 92 kWh / ton of cement, both of which were significantly lower than those of the control group 1. Compared with the control group 2, the carbon emissions and energy consumption of the experimental group were slightly higher, but the strength performance was greatly improved, reflecting the value of the activation process. In terms of waste utilization rate, both the experimental group and the control group 2 reached 60%, achieving waste resource utilization.

[0078] 3. Durability test

[0079] 100mm×100mm×100mm cubic specimens were prepared for permeability and frost resistance tests, and Φ50mm×50mm cylindrical specimens were prepared for corrosion resistance tests, with 6 specimens per group. Permeability was tested according to GB / T 50082-2009 "Standard for Testing Methods of Long-term Performance and Durability of Ordinary Concrete", using a concrete permeameter. Frost resistance was tested according to GB / T 50082-2009, with 50 cycles of freeze-thaw cycles, measuring mass loss rate and relative dynamic elastic modulus loss. Corrosion resistance was tested by immersing in a 5% sodium sulfate solution for 28 days, and testing the compressive strength loss rate.

[0080] The experimental results are shown in the table below.

[0081] Group Permeability coefficient (x 10 -12 m / s) Freeze-thaw mass loss (%) Freeze-thaw strength loss (%) Sulfate erosion strength loss (%) Experimental group 0.8 1.5 7.2 6.5 Control group 1 1.6 3.2 12.8 13.4 Control group 2 3.5 4.7 18.3 21.6

[0082] From the above, the experimental group is superior to the control group 1 and the control group 2 in terms of anti-permeability, anti-freezing and corrosion resistance, and its low permeability coefficient and small freeze-thaw loss indicate that the geopolymer structure is dense and has excellent durability. The poor performance of the control group 2 further verifies the key role of the activation process in improving the microstructure and durability.

[0083] The geopolymer cement of the present application has excellent performance in mechanical properties, environmental benefits and durability, and not only has strength comparable to ordinary Portland cement, but also is low-carbon, environmentally friendly and durable, and has a wide application prospect.

[0084] Application Case 1: Application in road base / floor material

[0085] The application scenario is a heavy transport road base repair project in a mining area.

[0086] The geopolymer cement prepared by the present application is mixed with graded gravel at a mass ratio of 1:4, an appropriate amount of water is added, and the mixture is uniformly mixed by plant mixing method, then transported to the site for paving, and rolled to a compaction degree ≥ 95% using a 20-ton roller.

[0087] The 7-day unconfined compressive strength reaches 4.5 MPa, and the 28-day strength is stably above 8.0 MPa, meeting the strength requirements of heavy road base. The strength retention rate of the base specimen after immersion is as high as 92%, much higher than that of traditional cement stabilized gravel, showing excellent water damage resistance. Compared with traditional cement base, the material cost is reduced by about 15%, and the on-site resource utilization of locally produced coal gangue in the mining area is realized.

[0088] Application Case 2: Application in light aggregate concrete preparation

[0089] The application scenario is to prepare A3.5 B06 grade light aggregate concrete block for building non-load-bearing partition wall.

[0090] The geopolymer cement of the present application is mixed with ceramsite with a particle size of 5-16 mm at a mass ratio of 1:2, the water-binder ratio is controlled at 0.38, and then mixed by a forced mixer, and then vibrated and formed by a block forming machine, and then steam cured at 40°C for 24 hours.

[0091] The dry density of the finished concrete is 1650 kg / m³, meeting the requirements of B06 grade, effectively reducing the self-weight of the building. The compressive strength reaches 4.2 MPa, meeting the requirements of A3.5 grade. The thermal conductivity is 0.35 W / (m·K), having good building thermal insulation performance. The content of solid waste such as coal gangue and fly ash in the product is more than 70%, which is a green building material product.

[0092] Application Case 3: Application in soil stabilizer

[0093] The application scenario is in-situ solidification of high-moisture silt soil in a river embankment project.

[0094] The silt soil with a moisture content of about 45% is added with 12% of the geopolymer cement powder of the application, uniformly mixed in-situ using a rotary tiller mixer, and then spread and rolled.

[0095] The solidified soil has a 7-day unconfined compressive strength of 1.8 MPa and a 28-day strength of 2.8 MPa, meeting the embankment filling strength requirement. The solidified body does not disintegrate after being soaked in water for 7 days, and the strength retention rate is more than 85%, showing strong resistance to water scouring. The geopolymer cement is alkaline, and can effectively solidify / stabilize part of heavy metal ions in the soil. After detection, the heavy metal leaching concentration in the solidified soil is far below the national standard limit.

[0096] Application Case 4: Application in water treatment adsorption materials

[0097] The application scenario is the removal of Cu 2+ ions in simulated electroplating wastewater by adsorption.

[0098] The geopolymer cement slurry of the application is granulated into 1-2 mm particles, and after curing and drying, a porous adsorbent is prepared. 1 g of the adsorbent is put into 100 mL of simulated wastewater with an initial Cu 2+ concentration of 50 mg / L, and shaken at 150 rpm for 2 hours at 25°C.

[0099] The adsorption rate of Cu 2+ is as high as 96%, and the saturated adsorption capacity reaches 28.5 mg / g. The specific surface area of the prepared granular adsorbent reaches 650 m² / kg, and the internal structure is rich in pores. In the pH range of 4-10, the adsorbent structure is stable and does not disintegrate significantly, and the Cu 2+ removal rate remains above 90%. The main raw material is coal gangue, and the cost is much lower than that of commercial activated carbon, providing an economical and efficient adsorption material option for industrial wastewater advanced treatment.

[0100] The above only describes certain exemplary embodiments of the application by way of illustration, and it is needless to say that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the application. Therefore, the above figures and description are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the application.

Claims

1. A geopolymer cement based on coal gangue activation reaction, characterized in that, The raw materials are composed of activated coal gangue powder 50-70%, alkali activator 5-15%, auxiliary cementing material 10-30%, and water, wherein the water is 30-40% of the total mass of the activated coal gangue powder, the alkali activator and the auxiliary cementing material.

2. The coal gangue-based geopolymer cement according to claim 1, characterized in that: The activated coal gangue powder is decarburized at 500-800℃ by a rotary calcination device, and has a carbon content of 15-17% and a particle size of ≤20μm and a specific surface area of ≥500 m² / kg after being treated by a superfine airflow grinding machine.

3. The coal gangue-based geopolymer cement according to claim 1, characterized in that: The alkali activator comprises sodium methyl silicate and sodium silicate, and the sodium methyl silicate accounts for 30-50% of the total mass of the alkali activator, has a purity of ≥98%, and the sodium silicate has a modulus of 1.5-3.

5.

4. The coal gangue-based geopolymer cement according to claim 1, characterized in that: The auxiliary cementing material comprises at least one of slag powder and fly ash, and the slag powder has a specific surface area of ≥400 m² / kg, and the fly ash is grade I or grade II fly ash.

5. The preparation method of the coal gangue activation reaction-based geopolymer cement according to any one of claims 1-4, characterized in that, The method comprises the following steps: Step 1: coal gangue pretreatment: coal gangue with a carbon content of 15-17% is crushed to a particle size of ≤5mm, and is calcined at 500-800℃ for 1-2 hours in a rotary calcination device to decarburize and activate the silicon and aluminum components; Step 2: superfine grinding: the calcined coal gangue is put into a superfine airflow grinding machine to grind to a particle size of ≤20μm and a specific surface area of ≥500 m² / kg to obtain activated coal gangue powder; Step 3: mixing and activation: the activated coal gangue powder, the auxiliary cementing material and the alkali activator are dry mixed uniformly, water is added and stirred to form a slurry, the water-binder ratio is 0.30-0.40, the stirring time is ≥3 minutes, and the slurry is cured at 20-40℃ for 24-48 hours to obtain early strength.

6. The preparation method of the coal gangue activation reaction-based geopolymer cement according to claim 5, characterized in that: In the step 1, the calcination stage adopts oxygen enrichment combustion technology, and oxygen-enriched air with an oxygen concentration of 25-30% is introduced to make the carbon in the coal gangue burn efficiently.

7. The preparation method of the coal gangue activation reaction-based geopolymer cement according to claim 1, characterized in that: In the step 2, the superfine grinding stage adopts a three-ring medium-speed superfine grinding machine, and the grinding temperature is controlled to be ≤60℃ to prevent the decomposition of active components.

8. The preparation method of the coal gangue activation reaction-based geopolymer cement according to claim 1, characterized in that: In the step 3, the dry mixing time is 1-2 minutes, and the stirring speed is 100-200 rpm to ensure uniform mixing.

9. Application of the coal gangue activation reaction-based geopolymer cement according to any one of claims 1-4 in road base / floor materials, light aggregate concrete preparation, soil solidifying agents, and water treatment adsorption materials.

10. Use according to claim 9, characterized in that: When the geopolymer cement is used in road base / floor materials, the geopolymer cement is mixed with aggregate at a mass ratio of 1:3-1:5, and the compaction degree is ≥95%; when the geopolymer cement is used in light aggregate concrete preparation, the geopolymer cement is mixed with light aggregate at a mass ratio of 1:1-1:3, and the dry density is ≤1800 kg / m³; when the geopolymer cement is used in soil solidifying agents, the addition amount is 5-15% of the mass of the soil, and the unconfined compressive strength of the solidified soil is ≥2MPa; and when the geopolymer cement is used in water treatment adsorption materials, the geopolymer cement is made into granular adsorbents with a specific surface area of ≥600 m² / kg and an adsorption rate of heavy metal ions of ≥90%.

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