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

Abstract

The invention relates to the technical field of building materials, in particular to high-strength power plant slag-based unfired ceramsite and a preparation method thereof.The preparation method comprises the following steps that S1, power plant slag is crushed and screened; s2, dissolving sodium silicate and sodium hydroxide in water, and stirring to form an alkaline activator solution; s3, the prepared materials are put into mixing equipment, and a dry mixture is obtained; s4, adding an alkaline activator solution into the dry mixture, and carrying out wet mixing until a plastic blank is formed; s5, the plastic blank is subjected to aging treatment; s6, raw ceramsite is formed through granulation equipment, and curing is conducted to form basic ceramsite; and S7, carrying out surface hydrophobization treatment on the cured basic ceramsite, and drying to obtain an unfired ceramsite finished product. According to the invention, the high-performance ceramsite is prepared by taking high-volume power plant slag as a main raw material through a sintering-free process, and has the comprehensive advantages of high strength, good durability, low cost and excellent environmental protection property.

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-fired ceramsite and its preparation method. Background Technology

[0002] Power plant slag is a large amount of solid waste generated during the power generation process of coal-fired power plants. Its storage and disposal not only occupy land resources but also pose environmental risks. Traditional ceramsite, as a lightweight building material, is usually made from raw materials such as clay and shale through a high-temperature sintering process. This process consumes a lot of energy and is accompanied by significant carbon emissions, which is contrary to the current requirements for green and low-carbon development. Therefore, the industry has begun to explore the technology of preparing non-fired ceramsite from solid waste in order to achieve the recycling of resources.

[0003] However, existing non-fired ceramsite technology, especially systems using power plant slag as the main raw material, still faces many severe challenges. Commonly used cement-based or alkali-activated cementitious systems suffer from insufficient strength development, limited solid waste content, and poor product durability. Furthermore, production processes often rely on steam curing or high-pressure molding, resulting in complex processes and high equipment investment costs. These shortcomings severely restrict the high-value-added resource utilization of power plant slag. Therefore, there is an urgent need for a high-strength power plant slag-based non-fired ceramsite 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-fired ceramsite and its preparation method.

[0005] A high-strength, non-fired ceramsite based on power plant slag comprises power plant slag, power plant fly ash, blast furnace slag, sodium silicate, sodium hydroxide, gypsum dihydrate, silica fume, and magnesium oxide; wherein each component is expressed in the following mass percentages:

[0006] Power plant slag accounts for 24-65%;

[0007] Fly ash accounts for 10-20% of the total emissions from power plants;

[0008] Slag accounts for 10-20%;

[0009] Sodium silicate accounts for 6-14%;

[0010] Sodium hydroxide accounts for 2-5%;

[0011] The proportion of dihydrate gypsum is 1-4%;

[0012] Silica fume accounts for 5-10%;

[0013] Magnesium oxide accounts for 1-3%.

[0014] Optionally, the percentages of each component are as follows: 44% power plant slag, 15% power plant fly ash, 15% blast furnace slag, 10% sodium silicate, 4% sodium hydroxide, 3% gypsum dihydrate, 7% silica fume, and 2% magnesium oxide.

[0015] A method for preparing high-strength power plant slag-based non-fired ceramsite, comprising the following steps:

[0016] S1: Crushing and screening power plant slag;

[0017] S2: Dissolve sodium silicate and sodium hydroxide in water and stir to form a uniform alkaline activator solution;

[0018] S3: The treated power plant slag, power plant fly ash, slag, dihydrate gypsum, silica fume and magnesium oxide are put into the mixing equipment for dry mixing to obtain a uniform dry mixture.

[0019] S4: Add the alkaline activator solution to the dry mix and perform wet mixing until a uniform plastic blank is formed;

[0020] S5: The plastic blank is aged to homogenize the moisture content;

[0021] S6: The aged plastic blank is shaped into raw ceramsite through a granulation device and then placed in a constant temperature and humidity environment for curing to form basic ceramsite.

[0022] S7: After curing, the basic ceramsite is subjected to surface hydrophobic treatment and dried to obtain the final non-fired ceramsite product.

[0023] Optionally, S1 specifically includes:

[0024] S11: Use a jaw crusher to perform primary crushing of power plant slag until its particle size does not exceed 10mm.

[0025] S12: The primary crushed slag is fed into a ball mill for grinding until its specific surface area reaches 80-120 m². 2 / kg;

[0026] S13: The ground slag powder is sieved through a 30-mesh vibrating screen, and the undersize material is used as raw material for power plant slag.

[0027] Optionally, S2 specifically includes:

[0028] S21: Raise the water temperature to 35-45℃;

[0029] S22: Add sodium silicate to water, wherein the mass ratio of sodium silicate to water is 1:2-1:4, and stir at 200-300 rpm for 3-5 minutes until completely dissolved to form a sodium silicate solution;

[0030] S23: While stirring continuously, slowly add solid sodium hydroxide at a rate of 50-100 g / min until the sodium hydroxide is completely dissolved.

[0031] S24: After complete dissolution, continue stirring at 200-300 rpm for 10-15 minutes until an alkaline activator solution is formed.

[0032] Optionally, S3 specifically includes:

[0033] S31: Add the raw materials to the twin-shaft paddle mixer in sequence. Specifically, first add the power plant slag and fly ash, and mix at 100-150 rpm for 2-3 minutes; then add the slag, gypsum dihydrate, and silica fume, and continue mixing at 100-150 rpm for 3-4 minutes; finally add the magnesium oxide and mix for 1-2 minutes.

[0034] S32: After all raw materials have been added, increase the speed of the mixer to 200-250 rpm and continue mixing for 5-8 minutes to obtain a uniform dry mix.

[0035] Optionally, S4 specifically includes:

[0036] S41: Use a pressure spraying device to uniformly spray the alkaline activator solution into the continuously stirred dry mixture at a flow rate of 5-8L / min. The spraying pressure is controlled at 0.3-0.5MPa, and the distance between the spray gun and the material is kept at 30-50cm.

[0037] S42: During the liquid addition process, keep the mixer speed at 120-150 rpm. After the liquid addition is completed, increase the speed to 250-300 rpm and continue mixing for 8-12 minutes to obtain a uniform plastic billet.

[0038] Optionally, S5 specifically includes:

[0039] S51: Transfer the plastic billet into a sealed aging chamber, maintaining the humidity of the chamber at 90-95% and the ambient temperature at 20-25℃.

[0040] S52: Let the plastic billet stand in the silo for 1.5-2 hours;

[0041] S53: Slowly turn the billet at a speed of 5-10 rpm for 3-5 minutes, and then let it stand for 1 hour to complete the aging process.

[0042] Optionally, S6 specifically includes:

[0043] S61: The aged plastic billet is continuously fed into a double-roller granulator. The roller pressure is set to 8-12MPa, the roller gap is adjusted to 3-5mm, and the cutting frequency is controlled at 25-35 times / minute to obtain raw ceramsite with a particle size of 5-15mm.

[0044] S62: Spread the raw ceramsite evenly in the curing tray, with a material layer thickness not exceeding 50mm, and immediately transfer it to a curing box with a temperature of 20℃ and a relative humidity of 95% and let it stand for 24 hours;

[0045] S63: Maintain a constant temperature and humidity environment for curing. Spray water mist 1-3 times a day to keep the surface moist. Continue curing for 27 days to obtain basic ceramsite. During this period, turn the ceramsite over once every 7 days.

[0046] Optionally, S7 specifically includes:

[0047] S71: The cured basic ceramsite is baked at 80±5℃ to constant weight, and then cooled to room temperature;

[0048] S72: Immerse the basic ceramsite in a 2-3 wt% silane coupling agent ethanol solution for 10-15 minutes, maintaining the solution temperature at 25-30℃.

[0049] S73: Remove the basic ceramsite from the solution and place it on a draining rack to drain naturally;

[0050] S74: Dry the drained basic ceramsite in a hot air circulating drying oven at 85±5℃ for 60-90 minutes to obtain the final non-fired ceramsite product.

[0051] The beneficial effects of this invention are:

[0052] This invention successfully solves the core problems of insufficient strength, low solid waste content, and poor durability in existing non-fired ceramsite technology by optimizing the raw material ratio and innovating the preparation process. The synergistic effect between various solid wastes and activators in the raw materials significantly improves the mechanical properties and stability of the ceramsite, while the unique molding and curing process avoids high-temperature sintering, greatly reducing energy consumption while ensuring structural formation.

[0053] This invention enables the efficient resource utilization of power plant slag, and the produced ceramsite has excellent physical properties and environmental adaptability. It not only significantly reduces production costs, but also provides a high-value-added transformation path for bulk industrial solid waste, which has important environmental and economic value. Attached Figure Description

[0054] 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.

[0055] Figure 1 This is a schematic diagram of the preparation method of power plant slag-based non-fired ceramsite according to an embodiment of the present invention. Detailed Implementation

[0056] 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.

[0057] 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.

[0058] 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.

[0059] Example 1

[0060] A high-strength, non-fired ceramsite based on power plant slag comprises power plant slag, power plant fly ash, blast furnace slag, sodium silicate, sodium hydroxide, gypsum dihydrate, silica fume, and magnesium oxide; wherein each component is expressed in the following mass percentages:

[0061] Power plant slag accounts for 24-65%;

[0062] Fly ash accounts for 10-20% of the total emissions from power plants;

[0063] Slag accounts for 10-20%;

[0064] Sodium silicate accounts for 6-14%;

[0065] Sodium hydroxide accounts for 2-5%;

[0066] The proportion of dihydrate gypsum is 1-4%;

[0067] Silica fume accounts for 5-10%;

[0068] Magnesium oxide accounts for 1-3%.

[0069] The percentages of each component are as follows: power plant slag 44%, power plant fly ash 15%, blast furnace slag 15%, sodium silicate 10%, sodium hydroxide 4%, gypsum dihydrate 3%, silica fume 7%, and magnesium oxide 2%.

[0070] like Figure 1 As shown, a method for preparing high-strength power plant slag-based non-fired ceramsite includes the following steps:

[0071] S1: Crushing and screening power plant slag;

[0072] S2: Dissolve sodium silicate and sodium hydroxide in water and stir to form a uniform alkaline activator solution;

[0073] S3: The treated power plant slag, power plant fly ash, slag, dihydrate gypsum, silica fume and magnesium oxide are put into the mixing equipment for dry mixing to obtain a uniform dry mixture.

[0074] S4: Add the alkaline activator solution to the dry mix and perform wet mixing until a uniform plastic blank is formed;

[0075] S5: The plastic blank is aged to homogenize the moisture content;

[0076] S6: The aged plastic blank is shaped into raw ceramsite through a granulation device and then placed in a constant temperature and humidity environment for curing to form basic ceramsite.

[0077] S7: After curing, the basic ceramsite is subjected to surface hydrophobic treatment and dried to obtain the final non-fired ceramsite product.

[0078] S1 specifically includes:

[0079] S11: Use a jaw crusher to perform primary crushing of power plant slag until its particle size does not exceed 10mm.

[0080] S12: The primary crushed slag is fed into a ball mill for grinding until its specific surface area reaches 100m². 2 / kg;

[0081] S13: The ground slag powder is sieved through a 30-mesh vibrating screen, and the undersize material is used as raw material for power plant slag.

[0082] S2 specifically includes:

[0083] S21: Raise the water temperature to 40℃;

[0084] S22: Add sodium silicate to water at a mass ratio of 1:3 and stir at 250 rpm for 4 minutes until completely dissolved to form a sodium silicate solution.

[0085] S23: While stirring continuously, slowly add solid sodium hydroxide at a rate of 80 g / min until the sodium hydroxide is completely dissolved.

[0086] S24: After complete dissolution, continue stirring at 250 rpm for 13 minutes until a clear, transparent, homogeneous alkaline activator solution is formed.

[0087] S3 specifically includes:

[0088] S31: Add the raw materials to the twin-shaft paddle mixer in sequence. Specifically, first add the power plant slag and fly ash, and mix at 130 rpm for 2.5 minutes; then add the slag, gypsum dihydrate, and silica fume, and continue mixing at 130 rpm for 3.5 minutes; finally add the magnesium oxide and mix for 1.5 minutes.

[0089] S32: After all raw materials are added, increase the speed of the mixer to 230 rpm and continue mixing for 6 minutes to obtain a uniform dry mix.

[0090] S4 specifically includes:

[0091] S41: Use a pressure spraying device to uniformly spray the alkaline activator solution into the continuously stirred dry mixture at a flow rate of 6L / min. The spraying pressure is controlled at 0.4MPa, and the distance between the spray gun and the material is kept at 40cm.

[0092] S42: During the liquid addition process, maintain the mixer speed at 130 rpm. After the liquid addition is completed, increase the speed to 280 rpm and continue mixing for 10 minutes to obtain a uniform plastic billet. In specific operation, take the mixed material and knead it into a ball. When it can be plasticized and there are no obvious cracks on the surface, and no slurry seeps out when held in the hand, it is judged to be a uniform plastic billet.

[0093] S5 specifically includes:

[0094] S51: Transfer the plastic billet into a sealed aging chamber, where the humidity is maintained at 93% and the temperature is maintained at 22℃.

[0095] S52: Let the plastic billet stand in the silo for 1.8 hours;

[0096] S53: Slowly turn the billet at 8 rpm for 4 minutes, then let it stand for another hour to complete the aging process.

[0097] S6 specifically includes:

[0098] S61: The aged plastic billet is continuously fed into a double-roller granulator. The roller pressure is set to 10MPa, the roller gap is adjusted to 4mm, and the cutting frequency is controlled at 30 times / minute to obtain raw ceramsite with a particle size of 12mm.

[0099] S62: Spread the raw ceramsite evenly in the curing tray with a material layer thickness of 40mm, and immediately transfer it to a curing box with a temperature of 20℃ and a relative humidity of 95% and let it stand for 24 hours.

[0100] S63: Maintain a constant temperature and humidity environment for curing. Spray water mist twice a day to keep the surface moist. Continue curing for 27 days to obtain basic ceramsite. During this period, turn the ceramsite over once every 7 days to ensure uniform curing.

[0101] S7 specifically includes:

[0102] S71: The cured basic ceramsite is baked at 80℃ to constant weight, and then cooled to room temperature;

[0103] S72: Immerse the basic ceramic particles in a 2.5wt% silane coupling agent ethanol solution for 13 minutes, while maintaining the solution temperature at 28℃.

[0104] S73: Remove the basic ceramsite from the solution and place it on a draining rack to drain naturally;

[0105] S74: Dry the drained basic ceramsite in a hot air circulating drying oven at 85℃ for 70 minutes to obtain the final non-fired ceramsite product.

[0106] Example 2

[0107] Formula composition:

[0108] The composition is as follows: 65% power plant slag, 10% power plant fly ash, 10% blast furnace slag, 6% sodium silicate, 2% sodium hydroxide, 1% gypsum dihydrate, 5% silica fume, and 1% magnesium oxide.

[0109] The preparation method is as follows:

[0110] S1: The power plant slag is initially crushed to a particle size of no more than 10mm using a jaw crusher; then it is ground in a ball mill to a specific surface area of ​​80m². 2 / kg; The ground slag is screened through a 30-mesh vibrating screen, and the undersize material is used as a spare raw material;

[0111] S2: Heat water to 35°C, add sodium silicate to water in a 1:2 mass ratio and stir at 200 rpm for 3 minutes to form a uniform solution; while stirring continuously, slowly add sodium hydroxide solid at a rate of 50 g / min, and after it is completely dissolved, continue stirring at 200 rpm for 10 minutes to obtain a uniform alkaline activator solution.

[0112] S3: Add power plant slag and fly ash to a twin-shaft paddle mixer in sequence and stir at 100 rpm for 2 minutes; then add slag, gypsum dihydrate, and silica fume in sequence and stir at the same speed for 3 minutes; finally add magnesium oxide and stir for 1 minute; after all the raw materials are added, increase the speed to 200 rpm and continue mixing for 5 minutes to obtain a uniform dry mix.

[0113] S4: Use a pressure spraying device to evenly spray the alkaline activator into the dry mixture at a flow rate of 5L / min. Control the spraying pressure at 0.3MPa and keep the distance between the spray gun and the material at 30cm. During the spraying process, maintain the mixing speed at 120rpm. After the spraying is completed, increase the speed to 250rpm and continue stirring for 8 minutes to obtain a uniform plastic billet.

[0114] S5: Transfer the plastic billet into a sealed aging chamber with a humidity of 90% and a temperature of 20°C, and let it stand for 1.5 hours; then turn it over at a speed of 5 rpm for 3 minutes, and let it stand for another hour to ensure that the moisture of the billet is fully homogenized.

[0115] S6: Feed the aged plastic billet into a double-roller granulator, set the roller pressure to 8MPa, the roller gap to 3mm, the cutting frequency to 25 times / minute, and the granulation particle size to 5mm; spread the raw ceramsite evenly in the curing tray, with a thickness of 40mm, and immediately transfer it to a curing box at 20℃ and 95% humidity for 24 hours, then continue curing for 27 days, turning it over every 7 days and spraying it with moisture once a day;

[0116] S7: After curing, the basic ceramsite is dried at 75℃ to constant weight. After cooling to room temperature, it is immersed in a 2wt% silane coupling agent ethanol solution for 10 minutes, while maintaining the solution temperature at 25℃. Then, it is taken out and placed on a draining rack to drain, and then sent to an 80℃ hot air circulating drying oven to dry for 60 minutes to obtain the final non-fired ceramsite product.

[0117] Example 3

[0118] Formula composition:

[0119] The composition is as follows: 24% power plant slag, 20% power plant fly ash, 20% blast furnace slag, 14% sodium silicate, 5% sodium hydroxide, 4% gypsum dihydrate, 10% silica fume, and 3% magnesium oxide.

[0120] The preparation method is as follows:

[0121] S1: The power plant slag is initially crushed to a particle size of no more than 10mm using a jaw crusher; then it is ground in a ball mill to a specific surface area of ​​120m². 2 / kg; The ground slag is screened through a 30-mesh vibrating screen, and the undersize material is used as a spare raw material;

[0122] S2: Heat water to 45°C, add sodium silicate to water in a 1:4 mass ratio to a stirring tank, and stir at 300 rpm for 5 minutes to form a uniform solution; while stirring continuously, slowly add sodium hydroxide solid at a rate of 100 g / min, and after it is completely dissolved, continue stirring at 300 rpm for 15 minutes to obtain a uniform alkaline activator solution.

[0123] S3: Add power plant slag and fly ash to a twin-shaft paddle mixer in sequence and stir at 150 rpm for 3 minutes; then add slag, gypsum dihydrate, and silica fume in sequence and stir at the same speed for 4 minutes; finally add magnesium oxide and stir for 2 minutes; after all the raw materials are added, increase the speed to 250 rpm and continue mixing for 8 minutes to obtain a uniform dry mix.

[0124] S4: Use a pressure spraying device to evenly spray the alkaline activator into the dry mixture at a flow rate of 8L / min. The spraying pressure is controlled at 0.5MPa, and the distance between the spray gun and the material is kept at 50cm. During the spraying process, the mixing speed is kept at 150rpm. After the spraying is completed, the speed is increased to 300rpm and the stirring is continued for 12 minutes to obtain a uniform plastic billet.

[0125] S5: Transfer the plastic billet into a sealed aging chamber with a humidity of 95% and a temperature of 25°C, and let it stand for 2 hours; then turn it over at 10 rpm for 5 minutes, and let it stand for another hour to ensure that the moisture of the billet is fully homogenized.

[0126] S6: The aged plastic billet is fed into a double-roller granulator. The roller pressure is set to 12MPa, the roller gap is 5mm, the cutting frequency is controlled at 35 times / minute, and the granulation particle size is 15mm. The raw ceramsite is evenly spread in the curing tray with a thickness of 30mm. It is then immediately transferred to a curing box with a temperature of 20℃ and a humidity of 95% and left to stand for 24 hours. It is then continuously cured for 27 days, turning it over every 7 days and spraying it with moisture 3 times a day.

[0127] S7: After curing, the basic ceramsite is dried at 85℃ to constant weight. After cooling to room temperature, it is immersed in a 3wt% silane coupling agent ethanol solution for 15 minutes, while maintaining the solution temperature at 30℃. Then, it is taken out and placed on a draining rack to drain, and then sent to an 85℃ hot air circulating drying oven to dry for 90 minutes to obtain the final non-fired ceramsite product.

[0128] Table 1 Comparison of performance parameters of finished non-fired ceramsite

[0129] index Test methods / conditions Example 1 Example 2 Example 3 28d cube compressive strength / MPa Standard maintenance for 28 days 11.8 9.6 10.7 Single particle compressive strength / N·particle φ10–15mm particles 420 350 380 <![CDATA[Bulk density / kg·m -3 > air dry 720 780 750 24h water absorption rate / % Soaking in water at room temperature 6.5 8.2 7.1 Apparent porosity / % Archimedes 18 22 20 Granulation rate (screen pass rate) / % 5–15 mm target particle size 93 88 91 Wear loss index / % 500 revolutions per minute 3.2 4.8 3.9 Freeze-thaw cycle mass loss / % 25 freeze-thaw cycles 0.9 1.6 1.2 <![CDATA[Thermal conductivity / W·m -1 ·K-1]]> Dry state, 25℃ 0.19 0.23 0.21 leachate pH (28d) / — Particles:water = 1:5 10.5 10.8 10.6

[0130] Note: The above wear loss index is the percentage of mass loss in the drum test; the particle size ratio is the percentage of the target particle size.

[0131] As can be seen from Table 1 above, Example 1 achieves the best balance between strength, durability, and lightweight, while maintaining low water absorption and low thermal conductivity, and its overall performance is superior to that of Examples 3 and 2. The combination of the activator ratio and silica fume in Example 1 is beneficial for forming a dense C-(A)-SH gel and for micro-expansion compensation; 100m 2 The fineness of the slag ( / kg), combined with aging at 93% RH and 22℃, plus long-term wet curing and silane hydrophobic treatment, reduces porosity and water absorption, thereby achieving higher strength and better durability while ensuring lightweight properties.

[0132] Table 2 Comparison of other performance aspects

[0133]

[0134]

[0135] Note:

[0136] The rate of thermal weight loss reflects the thermal stability of a material;

[0137] The gel activity index reflects the gelation efficiency (specific strength / active oxides);

[0138] The contact angle reflects hydrophobicity; a value greater than 90° indicates hydrophobicity, and the larger the better.

[0139] The cost of the alkali activator is estimated based on the combined average purchase price of sodium silicate and sodium hydroxide.

[0140] As can be seen from Table 2 above, Example 1 exhibits a thermal weight loss rate of only 1.4% at 800℃, far lower than Example 2, demonstrating superior high-temperature inertness; its linear shrinkage rate is only 0.12%, indicating a more compact and stable structure that is less prone to deformation; Example 1 has a gel activity index as high as 83.6%, more than 12 percentage points higher than Example 2, demonstrating excellent utilization of active components; at the same time, it has the lowest mass loss due to sulfuric acid corrosion, only 1.6%, indicating stronger acid resistance; after silane treatment, Example 1 achieves a contact angle of 112.4°, with significantly better hydrophobicity than the other two groups, effectively preventing moisture absorption and freeze-thaw cracking in subsequent applications; although Example 2 has a lower cost (63 yuan / ton) due to a smaller proportion of activator, its performance is significantly reduced; Example 1 controls the activator cost to 76 yuan / ton under the premise of optimal performance, with the lowest carbon emissions (48 kg CO2 / ton), achieving a balance between performance and environmental burden; the particle size concentration of the finished product of Example 1 reaches 93%, indicating stable process and concentrated particle size distribution, which is beneficial for subsequent screening and grading or direct engineering applications.

[0141] 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.

[0142] 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 ceramsite, characterized in that, It includes power plant slag, power plant fly ash, blast furnace slag, sodium silicate, sodium hydroxide, gypsum dihydrate, silica fume, and magnesium oxide; wherein each component is expressed as a percentage by mass. Power plant slag accounts for 24-65%; Fly ash accounts for 10-20% of the total emissions from power plants; Slag accounts for 10-20%; Sodium silicate accounts for 6-14%; Sodium hydroxide accounts for 2-5%; The proportion of dihydrate gypsum is 1-4%; Silica fume accounts for 5-10%; Magnesium oxide accounts for 1-3%.

2. The high-strength power plant slag-based non-fired ceramsite according to claim 1, characterized in that, The percentages of each component are as follows: power plant slag 44%, power plant fly ash 15%, blast furnace slag 15%, sodium silicate 10%, sodium hydroxide 4%, gypsum dihydrate 3%, silica fume 7%, and magnesium oxide 2%.

3. A method for preparing high-strength power plant slag-based non-fired ceramsite, used to prepare the high-strength power plant slag-based non-fired ceramsite according to any one of claims 1-2, characterized in that, Includes the following steps: S1: Crushing and screening power plant slag; S2: Dissolve sodium silicate and sodium hydroxide in water and stir to form a uniform alkaline activator solution; S3: The treated power plant slag, power plant fly ash, slag, dihydrate gypsum, silica fume and magnesium oxide are put into the mixing equipment for dry mixing to obtain a uniform dry mixture. S4: Add the alkaline activator solution to the dry mix and perform wet mixing until a uniform plastic blank is formed; S5: The plastic blank is aged to homogenize the moisture content; S6: The aged plastic blank is shaped into raw ceramsite through a granulation device and then placed in a constant temperature and humidity environment for curing to form basic ceramsite. S7: After curing, the basic ceramsite is subjected to surface hydrophobic treatment and dried to obtain the final non-fired ceramsite product.

4. The high-strength power plant slag-based non-fired ceramsite and its preparation method according to claim 1, characterized in that, S1 specifically includes: S11: Use a jaw crusher to perform primary crushing of power plant slag until its particle size does not exceed 10mm. S12: The primary crushed slag is fed into a ball mill for grinding until its specific surface area reaches 80-120 m². 2 / kg; S13: The ground slag powder is sieved through a 30-mesh vibrating screen, and the undersize material is used as raw material for power plant slag.

5. The high-strength power plant slag-based non-fired ceramsite and its preparation method according to claim 1, characterized in that, S2 specifically includes: S21: Raise the water temperature to 35-45℃; S22: Add sodium silicate to water, wherein the mass ratio of sodium silicate to water is 1:2-1:4, and stir at 200-300 rpm for 3-5 minutes until completely dissolved to form a sodium silicate solution; S23: While stirring continuously, slowly add solid sodium hydroxide at a rate of 50-100 g / min until the sodium hydroxide is completely dissolved. S24: After complete dissolution, continue stirring at 200-300 rpm for 10-15 minutes until an alkaline activator solution is formed.

6. The high-strength power plant slag-based non-fired ceramsite and its preparation method according to claim 1, characterized in that, S3 specifically includes: S31: Add the raw materials to the twin-shaft paddle mixer in sequence. Specifically, first add the power plant slag and fly ash, and mix at 100-150 rpm for 2-3 minutes; then add the slag, gypsum dihydrate, and silica fume, and continue mixing at 100-150 rpm for 3-4 minutes; finally add the magnesium oxide and mix for 1-2 minutes. S32: After all raw materials have been added, increase the speed of the mixer to 200-250 rpm and continue mixing for 5-8 minutes to obtain a uniform dry mix.

7. The high-strength power plant slag-based non-fired ceramsite and its preparation method according to claim 1, characterized in that, S4 specifically includes: S41: Use a pressure spraying device to uniformly spray the alkaline activator solution into the continuously stirred dry mixture at a flow rate of 5-8L / min. The spraying pressure is controlled at 0.3-0.5MPa, and the distance between the spray gun and the material is kept at 30-50cm. S42: During the liquid addition process, keep the mixer speed at 120-150 rpm. After the liquid addition is completed, increase the speed to 250-300 rpm and continue mixing for 8-12 minutes to obtain a uniform plastic billet.

8. The high-strength power plant slag-based non-fired ceramsite and its preparation method according to claim 1, characterized in that, S5 specifically includes: S51: Transfer the plastic billet into a sealed aging chamber, maintaining the humidity of the chamber at 90-95% and the ambient temperature at 20-25℃. S52: Let the plastic billet stand in the silo for 1.5-2 hours; S53: Slowly turn the billet at a speed of 5-10 rpm for 3-5 minutes, and then let it stand for 1 hour to complete the aging process.

9. The high-strength power plant slag-based non-fired ceramsite and its preparation method according to claim 1, characterized in that, S6 specifically includes: S61: The aged plastic billet is continuously fed into a double-roller granulator. The roller pressure is set to 8-12MPa, the roller gap is adjusted to 3-5mm, and the cutting frequency is controlled at 25-35 times / minute to obtain raw ceramsite with a particle size of 5-15mm. S62: Spread the raw ceramsite evenly in the curing tray, with a material layer thickness not exceeding 50mm, and immediately transfer it to a curing box with a temperature of 20℃ and a relative humidity of 95% and let it stand for 24 hours; S63: Maintain a constant temperature and humidity environment for curing. Spray water mist 1-3 times a day to keep the surface moist. Continue curing for 27 days to obtain basic ceramsite. During this period, turn the ceramsite over once every 7 days.

10. The high-strength power plant slag-based non-fired ceramsite and its preparation method according to claim 1, characterized in that, Specifically, S7 includes: S71: The cured basic ceramsite is baked at 80±5℃ to constant weight, and then cooled to room temperature; S72: Immerse the basic ceramsite in a 2-3 wt% silane coupling agent ethanol solution for 10-15 minutes, maintaining the solution temperature at 25-30℃. S73: Remove the basic ceramsite from the solution and place it on a draining rack to drain naturally; S74: Dry the drained basic ceramsite in a hot air circulating drying oven at 85±5℃ for 60-90 minutes to obtain the final non-fired ceramsite product.

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