High-strength power plant slag-based unfired cementing material and preparation method thereof

Abstract

The invention relates to the technical field of building materials, in particular to a high-strength power plant slag-based unfired cementing material and a preparation method thereof.The preparation method comprises the following steps that S1, weighed power plant slag, pulverized fuel ash, slag, metakaolin and silica fume are subjected to co-grinding pretreatment; s2, adding the weighed sodium silicate and sodium hydroxide into water, stirring and dissolving to obtain an alkali activator solution; s3, putting the mixed powder obtained in the step S1 into a microwave reactor, and performing microwave irradiation activation; s4, stirring the mixed powder and an alkali activator solution to form slurry; s5, performing vacuum stirring on the slurry in the S4, injecting the slurry into a mold, performing vibration compaction, and then performing constant-temperature and constant-humidity sealed maintenance; and S6, after curing is finished, demolding is conducted, and a finished cementing material product is obtained. According to the invention, the power plant slag is used as a main material to prepare the high-strength unfired cementing material at normal temperature, so that high-valued utilization of solid wastes and low-carbon transformation of building material production are realized.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, and in particular to a high-strength power plant slag-based non-burning cementitious material and its preparation method. Background Technology

[0002] Traditional silicate cement production relies on high-temperature calcination processes, resulting in huge energy consumption and persistently high carbon emissions. The resource utilization of industrial solid waste has long faced bottlenecks: power plant slag is difficult to dissociate due to its active components, and existing technologies can only use it as a low-value-added material such as roadbed filling. Although fly ash has cementing potential, its dosage is limited in conventional non-calcined systems, making it unsuitable as a main material.

[0003] More seriously, current non-fired cementitious materials generally suffer from strength defects, struggling to break through strength thresholds under room temperature curing. Improving performance, however, requires high-temperature steam curing or the addition of expensive chemical activators, severely hindering large-scale application. Therefore, there is an urgent need for a high-strength power plant slag-based non-fired cementitious material and its preparation method to solve these problems. Summary of the Invention

[0004] To achieve the above objectives, the present invention provides a high-strength power plant slag-based non-burning cementitious material and its preparation method.

[0005] A high-strength power plant slag-based non-fired cementitious material comprises power plant slag, fly ash, blast furnace slag, sodium silicate, sodium hydroxide, gypsum dihydrate, metakaolin, and silica fume; wherein the components are expressed in the following mass percentages:

[0006] Power plant slag accounts for 36-59%;

[0007] Fly ash accounts for 10-15%;

[0008] Slag accounts for 10-20%;

[0009] Sodium silicate accounts for 9-11%;

[0010] Sodium hydroxide accounts for 3-4%;

[0011] The proportion of dihydrate gypsum is 3-4%;

[0012] The proportion of metakaolinite is 4-6%;

[0013] Silica ash accounts for 2-4%.

[0014] Optionally, the percentages of each component are as follows: 48% power plant slag, 12% fly ash, 15% blast furnace slag, 10% sodium silicate, 3.5% sodium hydroxide, 3.5% gypsum dihydrate, 5% metakaolin, and 3% silica fume.

[0015] A method for preparing a high-strength power plant slag-based non-burning cementitious material includes the following steps:

[0016] S1: The weighed power plant slag, fly ash, blast furnace slag, metakaolin, and silica fume are co-ground for pretreatment to obtain a mixed powder;

[0017] S2: Add the weighed sodium silicate and sodium hydroxide to water and stir to dissolve, then age the solution to obtain an alkaline activator solution;

[0018] S3: Place the mixed powder obtained in S1 into a microwave reactor for microwave irradiation activation;

[0019] S4: Dry mix the activated powder from S3 with gypsum dihydrate, then add the alkaline activator solution prepared in S2 and stir to form a slurry;

[0020] S5: Vacuum mix the slurry from S4, then inject it into the mold and vibrate it to compact it, followed by constant temperature and humidity sealing and curing.

[0021] S6: After curing, demold to obtain the finished cementitious material.

[0022] Optionally, S1 specifically includes:

[0023] S11: Mix power plant slag, fly ash and blast furnace slag and feed them into a ball mill, then coarsely grind them to a particle size D90≤100μm;

[0024] S12: Add metakaolin and silica fume to the coarsely ground material;

[0025] S13: Add water (equivalent to 5-10% of the total solid mass) as a grinding aid, and continue grinding until the specific surface area of ​​the mixed powder is 400-500 m². 2 / kg;

[0026] S14: Dry the powder after wet grinding of S13 to a moisture content of 1%, and pass it through a 200-mesh sieve to obtain the mixed powder.

[0027] Optionally, S2 specifically includes:

[0028] S21: Take water for later use, the mass of which is 1.8-2.2 times the total mass of sodium silicate and sodium hydroxide;

[0029] S22: Raise the water temperature to 40-60℃, add sodium silicate and stir at 200-400 rpm for 5-10 minutes until completely dissolved;

[0030] S23: During the stirring process in S22, add sodium hydroxide to the solution in 3-5 portions, with an interval of 2-3 minutes between each addition;

[0031] S24: Transfer the mixed solution to a sealed container and let it stand at 20-25°C for 24-48 hours;

[0032] S25: Filter the aged solution through a 200-mesh sieve to obtain an alkaline activator solution.

[0033] Optionally, S3 specifically includes:

[0034] S31: Spread the mixed powder obtained in S1 evenly on the microwave reactor tray, with a layer thickness of 1-3cm;

[0035] S32: Start the microwave reactor, control the power to 300-500W, and irradiate for 2-5 minutes;

[0036] S33: After irradiation, remove the powder and stir it for 2-3 minutes to ensure even heat distribution.

[0037] Optionally, S4 specifically includes:

[0038] S41: Add the activated powder from S3 and gypsum dihydrate to a planetary mixer and dry mix at 200-300 rpm for 3-5 minutes.

[0039] S42: Add the alkaline activator solution prepared in S2 to the mixer at a uniform speed;

[0040] S43: Mix in two stages. Specifically, in the first stage, mix at 200-300 rpm for 2-3 minutes; in the second stage, increase the speed to 800-1000 rpm and mix for 2-3 minutes to form a slurry.

[0041] Optionally, S5 specifically includes:

[0042] S51: Transfer the slurry obtained in S4 into a vacuum mixer, evacuate to -0.08 to -0.1 MPa, and stir at 450-550 rpm for 1-2 minutes;

[0043] S52: Return to normal pressure and let stand for 1-2 minutes;

[0044] S53: Inject the slurry into a standard 40×40×160mm mold, filling it to 95-98% of the mold volume;

[0045] S54: Place on a vibration table and vibrate for 30 seconds at a frequency of 45-50Hz and an amplitude of 0.4-0.6mm;

[0046] S55: Move the mold into a constant temperature and humidity chamber, immediately cover it with a plastic film and seal it, maintain the temperature inside the chamber at 20℃ and the relative humidity at 90%, and continue curing for 25-30 days.

[0047] Optionally, S6 specifically includes:

[0048] S61: After the curing is completed, turn off the power to the constant temperature and humidity chamber and let it stand for 2-3 hours;

[0049] S62: Remove the mold fixing bolts and use a hydraulic demolding machine to eject the specimen with a pressure of 0.5-1.0MPa to obtain the finished cementitious material.

[0050] The beneficial effects of this invention are:

[0051] This invention achieves the standard strength grade of a non-burning cementitious system using power plant slag as the main material under pure ambient temperature curing through innovative material composition design and process synergy; overcomes the low reactivity defect of slag through gradient activation technology, making it the main skeleton of the cementitious network; and eliminates the dependence on high temperature or expensive reagents by establishing a synergistic mechanism of directional dissolution of alkali activator and densification of micro-aggregates. Attached Figure Description

[0052] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0053] Figure 1 This is a schematic diagram illustrating the preparation method of slag-based non-fired cementitious material according to an embodiment of the present invention. Detailed Implementation

[0054] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should also be noted that, to make the embodiments more comprehensive, the following embodiments are the best and preferred embodiments, and those skilled in the art can use other alternative methods to implement some well-known technologies; moreover, the accompanying drawings are only for more specific description of the embodiments and are not intended to specifically limit the present invention.

[0055] It should be noted that the use of terms such as "an embodiment," "an embodiment," "an exemplary embodiment," and "some embodiments" in the specification indicates that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments (whether explicitly described or not) should be within the knowledge of those skilled in the art.

[0056] Generally, terms can be understood at least partly from their use in context. For example, depending at least partly on the context, the term "one or more" as used herein can be used to describe any feature, structure, or characteristic in a singular sense, or a combination of features, structures, or characteristics in a plural sense. Additionally, the term "based on" can be understood not necessarily to convey an exclusive set of factors, but rather, alternatively, depending at least partly on the context, to allow for the presence of other factors that are not necessarily explicitly described.

[0057] Example 1

[0058] A high-strength power plant slag-based non-fired cementitious material comprises power plant slag, fly ash, blast furnace slag, sodium silicate, sodium hydroxide, gypsum dihydrate, metakaolin, and silica fume; wherein the components, by mass percentage, are: power plant slag 48%, fly ash 12%, blast furnace slag 15%, sodium silicate 10%, sodium hydroxide 3.5%, gypsum dihydrate 3.5%, metakaolin 5%, and silica fume 3%.

[0059] like Figure 1 As shown, a method for preparing a high-strength power plant slag-based non-burning cementitious material includes the following steps:

[0060] S1: The weighed power plant slag, fly ash, blast furnace slag, metakaolin, and silica fume are co-ground for pretreatment to obtain a mixed powder;

[0061] S2: Add the weighed sodium silicate and sodium hydroxide to water and stir to dissolve, then age the solution to obtain an alkaline activator solution;

[0062] S3: Place the mixed powder obtained in S1 into a microwave reactor for microwave irradiation activation;

[0063] S4: Dry mix the activated powder from S3 with gypsum dihydrate, then add the alkaline activator solution prepared in S2 and stir to form a slurry;

[0064] S5: Vacuum mix the slurry from S4, then inject it into the mold and vibrate it to compact it, followed by constant temperature and humidity sealing and curing.

[0065] S6: After curing, demold to obtain the finished cementitious material.

[0066] S1 specifically includes:

[0067] S11: Mix power plant slag, fly ash and blast furnace slag and feed them into a ball mill, then coarsely grind them to a particle size of 90μm;

[0068] S12: Add metakaolin and silica fume to the coarsely ground material;

[0069] S13: Add water equivalent to 8% of the total solid mass as a grinding aid, and continue grinding until the specific surface area of ​​the mixed powder is 450m². 2 / kg;

[0070] S14: Dry the powder after wet grinding of S13 to a moisture content of 1%, and pass it through a 200-mesh sieve to obtain the mixed powder.

[0071] S2 specifically includes:

[0072] S21: Take water for later use, the mass of which is twice the total mass of sodium silicate and sodium hydroxide;

[0073] S22: Raise the water temperature to 50℃, add sodium silicate and stir at 300rpm for 8 minutes until completely dissolved;

[0074] S23: During the stirring process in S22, sodium hydroxide is added to the solution in 4 portions, with an interval of 2.5 minutes between each addition;

[0075] S24: Transfer the mixed solution to a sealed container and let it stand at 23°C for 36 hours;

[0076] S25: Filter the aged solution through a 200-mesh sieve to obtain an alkaline activator solution.

[0077] S3 specifically includes:

[0078] S31: Spread the mixed powder obtained in S1 evenly on the microwave reactor tray, with a layer thickness of 2cm;

[0079] S32: Start the microwave reactor, control the power at 400W, and irradiate for 3 minutes;

[0080] S33: After irradiation, remove the powder and stir it for 2.5 minutes to ensure even heat distribution.

[0081] S4 specifically includes:

[0082] S41: Add the activated powder from S3 and gypsum dihydrate to a planetary mixer and dry mix at 250 rpm for 4 minutes.

[0083] S42: Add the alkaline activator solution prepared in S2 to the mixer at a uniform speed;

[0084] S43: Mix in two stages. Specifically, in the first stage, mix at 250 rpm for 2.5 minutes; in the second stage, increase the speed to 900 rpm and mix for 2.5 minutes to form a slurry.

[0085] S5 specifically includes:

[0086] S51: Transfer the slurry obtained in S4 into a vacuum mixer, evacuate to -0.09MPa, and stir at 500rpm for 1.5 minutes;

[0087] S52: Return to normal pressure and let stand for 1.5 minutes;

[0088] S53: Inject the slurry into a standard 40×40×160mm mold, filling it to 96% of its volume;

[0089] S54: Place on a vibration table and vibrate for 30 seconds at a frequency of 48Hz and an amplitude of 0.5mm;

[0090] S55: Move the mold into a constant temperature and humidity chamber, immediately cover it with a plastic film and seal it, maintain the temperature inside the chamber at 20℃ and the relative humidity at 90%, and continue curing for 28 days.

[0091] S6 specifically includes:

[0092] S61: After the curing is completed, turn off the power to the constant temperature and humidity chamber and let it stand for 2.5 hours;

[0093] S62: Remove the mold fixing bolts and use a hydraulic demolding machine to eject the specimen with a pressure of 0.8MPa to obtain the finished cementitious material.

[0094] Example 2

[0095] Formula composition: 59% power plant slag, 10% fly ash, 10% blast furnace slag, 9% sodium silicate, 3% sodium hydroxide, 3% gypsum dihydrate, 4% metakaolin, and 2% silica fume.

[0096] The preparation process is as follows:

[0097] S1: Power plant slag, fly ash, and mineral slag are mixed in a certain proportion and then fed into a ball mill for coarse grinding, controlling the product particle size D90 to be 100μm; then metakaolin and silica fume are added, followed by water (5% of the total solid mass) as a grinding aid for continued wet grinding, so that the specific surface area of ​​the resulting mixed powder reaches approximately 400m². 2 / kg; The wet-milled mixture was dried to a moisture content of 1% and sieved through a 200-mesh sieve to obtain a uniform mixed powder;

[0098] S2: Weigh the total mass of sodium silicate and sodium hydroxide, and add 1.8 times the mass of water. First, heat the water to 40°C, then add sodium silicate at 200 rpm and stir for 5 minutes until completely dissolved. Then, slowly add sodium hydroxide to the solution in 3 portions, with an interval of 2 minutes between each addition. After completion, transfer the solution to a sealed container, let it stand and age at 20°C for 24 hours, and filter it through a 200-mesh sieve to obtain a clear and homogeneous alkali activator solution.

[0099] S3: Spread the mixed powder obtained in S1 evenly in the microwave reactor tray, with the layer thickness controlled within 1cm; start the reactor, set the power to 300W, and irradiate continuously for 2 minutes; after irradiation, remove the powder and stir it for 2 minutes to ensure that the heat is fully and evenly distributed in the powder.

[0100] S4: Add the activated mixed powder and gypsum dihydrate into a planetary mixer and dry mix at 200 rpm for 3 minutes; then inject the alkali activator solution prepared in S2 into the mixer at a uniform speed. In the first stage, stir at 200 rpm for 2 minutes to complete the initial dispersion. In the second stage, increase the stirring speed to 800 rpm for 2 minutes until a slurry with good fluidity is formed.

[0101] S5: Pour the slurry into a vacuum mixer, evacuate to -0.08MPa, and stir at 450rpm for 1 minute to remove air bubbles; then restore to normal pressure and let stand for 1 minute, then inject the slurry into a standard mold with dimensions of 40×40×160mm, filling the mold to 95% of its volume; place the mold on a vibration table, set the frequency to 45Hz, the amplitude to 0.4mm, and the vibration time to 30 seconds to achieve compaction; then transfer the mold to a constant temperature and humidity chamber, seal and cover it, maintain the temperature at 20℃ and the relative humidity at 90%, and cure continuously for 25 days;

[0102] S6: After the curing period, turn off the power of the constant temperature and humidity chamber and let the mold stand for 2 hours to relieve internal stress; then remove the mold bolts, apply a pressure of 0.5MPa using a hydraulic demolding machine, eject the finished gelling material and take it out to complete the preparation.

[0103] Example 3

[0104] Formula composition: 36% power plant slag, 15% fly ash, 20% blast furnace slag, 11% sodium silicate, 4% sodium hydroxide, 4% gypsum dihydrate, 6% metakaolin, and 4% silica fume.

[0105] The preparation process is as follows:

[0106] S1: Power plant slag, fly ash, and mineral slag are mixed in a certain proportion and then fed into a ball mill for coarse grinding, controlling the product particle size D90 to be 98μm; then metakaolin and silica fume are added, followed by water (10% of the total solid mass) as a grinding aid for continued wet grinding, so that the specific surface area of ​​the resulting mixed powder reaches approximately 500m². 2 / kg; The wet-milled mixture was dried to a moisture content of 1% and sieved through a 200-mesh sieve to obtain a uniform mixed powder;

[0107] S2: Weigh the total mass of sodium silicate and sodium hydroxide, and add 2.2 times the mass of water. First, heat the water to 60°C, then add sodium silicate at 400 rpm and stir for 10 minutes until completely dissolved. Then, slowly add sodium hydroxide to the solution in 5 portions, with an interval of 3 minutes between each addition. After completion, transfer the solution to a sealed container, let it stand and age at 25°C for 48 hours, and then filter it through a 200-mesh sieve to obtain a clear and homogeneous alkali activator solution.

[0108] S3: Spread the mixed powder obtained in S1 evenly in the microwave reactor tray, with the layer thickness controlled within 3cm; start the reactor, set the power to 500W, and irradiate continuously for 5 minutes; after irradiation, remove the powder and stir it for 3 minutes to ensure that the heat is fully and evenly distributed in the powder.

[0109] S4: Add the activated mixed powder and gypsum dihydrate into a planetary mixer and dry mix at 300 rpm for 5 minutes; then inject the alkali activator solution prepared in S2 into the mixer at a uniform speed. In the first stage, stir at 300 rpm for 3 minutes to complete the initial dispersion. In the second stage, increase the stirring speed to 1000 rpm for 3 minutes until a slurry with good fluidity is formed.

[0110] S5: Pour the slurry into a vacuum mixer, evacuate to -0.1MPa, and stir at 550rpm for 2 minutes to remove air bubbles; then restore to normal pressure and let stand for 2 minutes, then inject the slurry into a standard mold with dimensions of 40×40×160mm, filling the mold to 98% of its volume; place the mold on a vibration table, set the frequency to 50Hz, the amplitude to 0.6mm, and the vibration time to 30 seconds to achieve compaction; then transfer the mold to a constant temperature and humidity chamber, seal and cover it, maintain the temperature at 20℃ and the relative humidity at 90%, and cure continuously for 30 days;

[0111] S6: After the curing period, turn off the power of the constant temperature and humidity chamber and let the mold stand for 3 hours to relieve internal stress; then remove the mold bolts, use a hydraulic demolding machine to apply a pressure of 1.0MPa, eject the finished gelling material and take it out to complete the preparation.

[0112] Table 1 Comparison of Finished Product Performance Parameters

[0113]

[0114] As can be seen from Table 1 above, Example 1 outperforms Examples 2 and 3 in all eight key performance indicators, including compressive strength, flexural strength, density, porosity, water absorption, setting time, and drying shrinkage, and has the best overall performance. Example 2 has moderate performance in all aspects. Example 3 has the lowest performance in all indicators. Therefore, the formula and process parameters selected in Example 1 can best balance strength, durability, and workability, and are suitable as the best implementation method of this invention.

[0115] Table 2 Comparison of other parameters

[0116]

[0117]

[0118] As shown in Table 2 above, Example 1 is superior to the other two groups in terms of durability, including resistance to carbonation, sulfate attack, and freeze-thaw resistance, indicating that it has better stability in long-term service environments. At the same time, it has a low bleeding rate and high fluidity, resulting in better construction performance. Furthermore, it also performs best in terms of unit raw material cost and carbon emissions, demonstrating good economic efficiency and environmental friendliness.

[0119] In summary, Example 1 is optimal in terms of structural durability, construction adaptability, economy and environmental protection, and can be regarded as the optimal implementation of the present invention, with promotion and application value; Example 2 has moderate performance, while Example 3 is relatively low in terms of strength and durability, and is suitable for application scenarios with low requirements for cost and performance.

[0120] This invention encompasses any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of this invention. To provide the public with a thorough understanding of this invention, specific details are described in detail in the following preferred embodiments; however, those skilled in the art will fully understand the invention even without these details. Furthermore, to avoid unnecessary misunderstanding of the essence of this invention, well-known methods, processes, procedures, components, and circuits are not described in detail.

[0121] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A high-strength power plant slag-based non-fired cementitious material, characterized in that, It includes power plant slag, fly ash, mineral slag, sodium silicate, sodium hydroxide, gypsum dihydrate, metakaolin, and silica fume; the components are expressed as follows by mass percentage: Power plant slag accounts for 36-59%; Fly ash accounts for 10-15%; Slag accounts for 10-20%; Sodium silicate accounts for 9-11%; Sodium hydroxide accounts for 3-4%; The proportion of dihydrate gypsum is 3-4%; The proportion of metakaolinite is 4-6%; Silica ash accounts for 2-4%.

2. The high-strength power plant slag-based non-fired cementitious material according to claim 1, characterized in that, The percentages of each component are as follows: power plant slag 48%, fly ash 12%, blast furnace slag 15%, sodium silicate 10%, sodium hydroxide 3.5%, gypsum dihydrate 3.5%, metakaolin 5%, and silica fume 3%.

3. A method for preparing a high-strength power plant slag-based non-burning cementitious material, used to prepare the high-strength power plant slag-based non-burning cementitious material according to any one of claims 1-2, characterized in that, Includes the following steps: S1: The weighed power plant slag, fly ash, blast furnace slag, metakaolin, and silica fume are co-ground for pretreatment to obtain a mixed powder; S2: Add the weighed sodium silicate and sodium hydroxide to water and stir to dissolve, then age the solution to obtain an alkaline activator solution; S3: Place the mixed powder obtained in S1 into a microwave reactor for microwave irradiation activation; S4: Dry mix the activated powder from S3 with gypsum dihydrate, then add the alkaline activator solution prepared in S2 and stir to form a slurry; S5: Vacuum mix the slurry from S4, inject it into the mold and vibrate to compact it, then perform constant temperature and humidity sealing curing. S6: After curing, demold to obtain the finished cementitious material.

4. The preparation method of a high-strength power plant slag-based non-fired cementitious material according to claim 3, characterized in that, S1 specifically includes: S11: Mix power plant slag, fly ash and blast furnace slag and feed them into a ball mill, then coarsely grind them to a particle size D90≤100μm; S12: Add metakaolin and silica fume to the coarsely ground material; S13: Add water (equivalent to 5-10% of the total solid mass) as a grinding aid, and continue grinding until the specific surface area of ​​the mixed powder is 400-500 m². 2 / kg; S14: Dry the powder after wet grinding of S13 to a moisture content of 1%, and pass it through a 200-mesh sieve to obtain the mixed powder.

5. The preparation method of a high-strength power plant slag-based non-fired cementitious material according to claim 3, characterized in that, S2 specifically includes: S21: Take water for later use, the mass of which is 1.8-2.2 times the total mass of sodium silicate and sodium hydroxide; S22: Raise the water temperature to 40-60℃, add sodium silicate and stir at 200-400 rpm for 5-10 minutes until completely dissolved; S23: During the stirring process in S22, add sodium hydroxide to the solution in 3-5 portions, with an interval of 2-3 minutes between each addition; S24: Transfer the mixed solution to a sealed container and let it stand at 20-25°C for 24-48 hours; S25: Filter the aged solution through a 200-mesh sieve to obtain an alkaline activator solution.

6. The method for preparing a high-strength power plant slag-based non-fired cementitious material according to claim 3, characterized in that, S3 specifically includes: S31: Spread the mixed powder obtained in S1 evenly on the microwave reactor tray, with a layer thickness of 1-3cm; S32: Start the microwave reactor, control the power to 300-500W, and irradiate for 2-5 minutes; S33: After irradiation, remove the powder and stir it for 2-3 minutes to ensure even heat distribution.

7. The preparation method of a high-strength power plant slag-based non-fired cementitious material according to claim 3, characterized in that, S4 specifically includes: S41: Add the activated powder from S3 and gypsum dihydrate to a planetary mixer and dry mix at 200-300 rpm for 3-5 minutes. S42: Add the alkaline activator solution prepared in S2 to the mixer at a uniform speed; S43: Mix in two stages. Specifically, in the first stage, mix at 200-300 rpm for 2-3 minutes; in the second stage, increase the speed to 800-1000 rpm and mix for 2-3 minutes to form a slurry.

8. The preparation method of a high-strength power plant slag-based non-fired cementitious material according to claim 3, characterized in that, S5 specifically includes: S51: Transfer the slurry obtained in S4 into a vacuum mixer, evacuate to -0.08 to -0.1 MPa, and stir at 450-550 rpm for 1-2 minutes; S52: Return to normal pressure and let stand for 1-2 minutes; S53: Inject the slurry into a standard 40×40×160mm mold, filling it to 95-98% of the mold volume; S54: Place on a vibration table and vibrate for 30 seconds at a frequency of 45-50Hz and an amplitude of 0.4-0.6mm; S55: Move the mold into a constant temperature and humidity chamber, immediately cover it with a plastic film and seal it, maintain the temperature inside the chamber at 20℃ and the relative humidity at 90%, and continue curing for 25-30 days.

9. The method for preparing a high-strength power plant slag-based non-fired cementitious material according to claim 3, characterized in that, S6 specifically includes: S61: After the curing is completed, turn off the power to the constant temperature and humidity chamber and let it stand for 2-3 hours; S62: Remove the mold fixing bolts and use a hydraulic demolding machine to eject the specimen with a pressure of 0.5-1.0MPa to obtain the finished cementitious material.

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