Solid-waste-based phase-change energy-storage lightweight aggregate applied to marine concrete and preparation method of solid-waste-based phase-change energy-storage lightweight aggregate

Abstract

The invention provides solid-waste-based phase-change energy-storage lightweight aggregate applied to marine concrete and a preparation method of the solid-waste-based phase-change energy-storage lightweight aggregate, and belongs to the technical field of building materials. According to the invention, solid wastes such as coal gangue and fly ash are adopted as raw materials to prepare the ceramsite, and the ratio and firing conditions of the raw materials such as coal gangue and fly ash are adjusted to improve the mechanical properties such as mechanical strength and adhesive property of the ceramsite, so that the ceramsite is more suitable for marine concrete; and then liquid paraffin is injected into the ceramsite in a vacuum impregnation manner, so that the frost heaving resistance, temperature stress resistance and impact resistance of the marine concrete can be remarkably improved. Through three core innovations of solid waste resource utilization, lightweight high-strength aggregate preparation and phase change energy storage function integration, the problems of single material performance, high process consumption, low efficiency, insufficient function integration and the like in the prior art are systematically solved.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, and in particular to a solid waste-based phase change energy storage lightweight aggregate applied to marine engineering concrete and a preparation method thereof. Background Art

[0002] Marine engineering requires concrete to have excellent seawater erosion resistance, freeze-thaw resistance and high tolerance to temperature stress. Due to its own characteristics, traditional marine engineering concrete is difficult to meet the actual needs, especially in terms of frost heaving resistance and resistance to temperature difference stress, and there are great deficiencies, which easily lead to cracking, spalling and even damage of the concrete structure.

[0003] To solve the above problems, the prior art has been improved from the following aspects: (1) Development of alternative materials for traditional aggregates: using industrial by-products (such as slag, steel slag) to replace natural sand and gravel; (2) Solid waste resource utilization technology: using solid waste such as coal gangue to prepare concrete recycled aggregates; (3) Application of phase change energy storage materials: mostly directly mixing phase change materials (such as microcapsule paraffin) into concrete. However, the above methods have the following problems: 1) Using industrial by-products (such as slag, steel slag) to replace natural sand and gravel as aggregates, due to the large density of the aggregates, the self-weight of the concrete increases, making it difficult to meet the lightweight requirements of marine engineering, and some industrial waste residues contain free calcium oxide or sulfides, which are prone to cause volume expansion or chemical corrosion, reducing the durability of the concrete, and the contact between steel slag and seawater will cause marine pollution; 2) The compressive strength of concrete recycled aggregates is insufficient (usually <5 MPa), making it difficult to meet the strength requirements of marine engineering concrete. At the same time, the temperature control is inaccurate during the calcination process (such as directly heating to 1200 °C), which easily leads to uneven internal structure of the aggregates; 3) There are problems such as easy leakage of phase change energy storage materials during the mixing and hardening process of concrete and weak interfacial bonding between the phase change energy storage materials and the cement matrix, resulting in a decrease in the compressive strength of the concrete by about 25%, causing great mechanical property losses. At the same time, the cost of phase change energy storage materials is high, greatly increasing the production cost.

[0004] Therefore, providing an aggregate with low cost and capable of improving the performance of marine engineering concrete has become an urgent technical problem in this field. Summary of the Invention

[0005] The purpose of the present invention is to provide a solid waste-based phase change energy storage lightweight aggregate applied to marine engineering concrete and a preparation method thereof. The preparation method provided by the present invention has a high solid waste utilization rate and low energy consumption. At the same time, the prepared solid waste-based phase change energy storage lightweight aggregate has a low density, high compressive strength, good freeze-thaw resistance, and can reduce the thermal conductivity of marine engineering concrete.

[0006] To achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0007] The present invention provides a preparation method of waste-based phase change energy storage lightweight aggregate applied to marine engineering concrete, comprising the following steps:

[0008] (1) Mix coal gangue particles and fly ash and then perform ball milling to obtain a mixed powder;

[0009] (2) Mix the mixed powder obtained in the step (1), a binder and water and then perform granulation to obtain green balls;

[0010] (3) Dry and calcine the green balls obtained in the step (2) in sequence to obtain ceramsite;

[0011] (4) Perform vacuum impregnation on the ceramsite obtained in the step (3) in liquid paraffin to obtain waste-based phase change energy storage lightweight aggregate.

[0012] Preferably, the particle size of the coal gangue particles in the step (1) is ≤5 cm.

[0013] Preferably, by mass percentage, the mixed powder in the step (1) comprises 60-80% of coal gangue particles and 20-40% of fly ash.

[0014] Preferably, the particle size of the mixed powder in the step (1) is ≤75 μm.

[0015] Preferably, the binder in the step (2) is sodium-based bentonite; the mass of the binder is 3-8% of the mass of the mixed powder.

[0016] Preferably, the mass percentage of water in the green balls in the step (2) is 10-18%.

[0017] Preferably, the particle size of the green balls in the step (2) is 5-10 mm.

[0018] Preferably, in the step (3), the calcination is to first raise the temperature at a heating rate of 5-15 °C / min to 400-600 °C for preheating for 20-60 min, and then raise the temperature at a heating rate of 15-30 °C / min to 1000-1400 °C for calcination for 30-60 min.

[0019] Preferably, the way of vacuum impregnation in the step (4) is to immerse the ceramsite in liquid paraffin, then evacuate for 0.5-2 h, the degree of vacuum for evacuation is -0.1 to -0.05 MPa, and then release the vacuum and let the ceramsite continue to soak in liquid paraffin for 1-2 h.

[0020] The present invention provides waste-based phase change energy storage lightweight aggregate applied to marine engineering concrete prepared by the preparation method described in the above technical solution.

[0021] The present invention provides a preparation method of solid waste-based phase change energy storage lightweight aggregate for marine concrete, comprising the following steps: (1) mixing coal gangue particles and fly ash and then performing ball milling to obtain a mixed powder; (2) mixing the mixed powder obtained in step (1), a binder and water and then performing granulation to obtain green pellets; (3) drying and calcining the green pellets obtained in step (2) in sequence to obtain ceramsite; (4) performing vacuum impregnation on the ceramsite obtained in step (3) in liquid paraffin to obtain the solid waste-based phase change energy storage lightweight aggregate. The present invention uses solid wastes such as coal gangue and fly ash as raw materials to prepare ceramsite, adjusts the ratios of raw materials such as coal gangue and fly ash and the firing conditions, improves the mechanical properties such as the mechanical strength and bonding performance of the ceramsite, so that it is more suitable for marine concrete, and then injects liquid paraffin into the interior of the ceramsite by means of vacuum impregnation, which can significantly improve the frost heaving resistance, temperature stress resistance and impact resistance of marine concrete. Through the three core innovations of solid waste resource utilization, preparation of lightweight and high-strength aggregate, and integration of phase change energy storage function, the present invention systematically solves the problems of single material performance, high consumption and low efficiency of the process, and insufficient function integration degree in the prior art. The preparation method provided by the present invention not only promotes the resource utilization of solid wastes, reduces the environmental burden, and provides a new technical path for the efficient utilization of solid wastes, but also improves the heat preservation performance and durability of marine concrete, and has been significantly improved in terms of environmental protection, economy and functionality. The preparation method provided by the present invention has a simplified process flow, does not require complex chemical synthesis steps, and is suitable for industrial production.The results of the examples show that the preparation method provided by the present invention uses coal gangue particles and fly ash as raw materials, and the solid waste utilization rate reaches more than 90%, which can reduce the stacking pollution of coal gangue and fly ash; at the same time, the ceramsite obtained by granulating and calcining coal gangue particles and fly ash can replace natural sand and gravel, reducing the damage to the ecological environment caused by resource exploitation; the energy consumption during the calcination process can be reduced by 15-20% compared with that of traditional clay ceramsite, saving energy and reducing production costs, meeting the requirements of green and low-carbon production; the obtained solid waste-based phase change energy storage lightweight aggregate has a low density, meeting the lightweight requirements of ocean engineering; at the same time, the lightweight aggregate has a high compressive strength (traditional solid waste-based aggregate < 5 MPa), which can significantly improve the bearing capacity of marine concrete, and a low porosity (traditional coal gangue aggregate > 30%), which can reduce the water absorption rate (≤ 5%) and improve the freeze-thaw resistance of marine concrete; the processing cost of raw materials during the preparation process is reduced by more than 50% (compared with the microcapsule process), and the raw material cost is saved by 40-60% (the price of natural sand and gravel is about 80-120 yuan / ton, and the cost of solid waste raw materials is almost zero); after the solid waste-based phase change energy storage lightweight aggregate is applied to marine concrete, compared with aggregates such as natural sand and gravel, the self-weight of marine concrete is reduced by 20-30%, significantly reducing the load on the foundation of marine structures, and the thermal stability of marine concrete is improved, and the temperature difference adaptation range is expanded to -30°C to 60°C (traditional concrete is -10°C to 50°C), and the chloride ion permeability resistance is increased by 50%, extending the service life of structures in the marine environment. Detailed implementation mode

[0022] The present invention provides a preparation method of a solid waste-based phase change energy storage lightweight aggregate applied to marine concrete, comprising the following steps:

[0023] (1) Mix coal gangue particles and fly ash and then carry out ball milling to obtain a mixed powder;

[0024] (2) Mix the mixed powder obtained in the step (1), a binder and water and then carry out granulation to obtain green balls;

[0025] (3) Dry and calcine the green balls obtained in the step (2) in sequence to obtain ceramsite;

[0026] (4) Carry out vacuum impregnation of the ceramsite obtained in the step (3) in liquid paraffin to obtain a solid waste-based phase change energy storage lightweight aggregate.

[0027] In the present invention, unless otherwise specified, the raw materials used are commercially available products well-known to those skilled in the art or are prepared by known methods.

[0028] In the present invention, coal gangue particles and fly ash are mixed and then ball-milled to obtain a mixed powder. The present invention uses coal gangue particles and fly ash as raw materials, and the solid waste utilization rate reaches more than 90%, which can reduce the stacking pollution of coal gangue and fly ash. At the same time, the ceramsite obtained by granulating and calcining coal gangue particles and fly ash can replace natural sand and gravel, reducing the damage to the ecological environment caused by resource exploitation.

[0029] In the present invention, the particle size of the coal gangue particles is preferably ≤ 5 cm. In the present invention, when the particle size of the coal gangue particles does not meet the above requirements, the present invention preferably performs a crushing treatment on the coal gangue particles. In the present invention, the crushing treatment is preferably carried out in a jaw crusher; the model of the jaw crusher is preferably PE-400×600. By controlling the particle size of the coal gangue particles in the present invention, subsequent mixing is facilitated.

[0030] In the present invention, by mass percentage, the mixed powder includes 60-80% of coal gangue particles and 20-40% of fly ash. As an embodiment of the present invention, the mass percentage of the coal gangue particles can be 65%, 70% or 75%; the mass percentage of the fly ash can be 25%, 30% or 35%. The present invention uses a mixture of coal gangue particles and fly ash to prepare ceramsite, and the fly ash makes up for the defect of weak compressive strength of coal gangue ceramsite, thereby ensuring that the obtained lightweight aggregate can endow the marine concrete with high mechanical properties.

[0031] In the present invention, the ball milling is preferably carried out in a ball mill; the model of the ball mill is preferably MQG1500×3000. The present invention has no special limitation on the specific parameters of the ball milling, as long as the particle size of the mixed powder meets the requirements.

[0032] The present invention preferably dries the product of the ball milling after the ball milling. In the present invention, the drying is preferably carried out in a drying oven; the drying temperature is preferably 100-150 °C; the drying time is preferably 1-4 h. As an embodiment of the present invention, the drying temperature can be 110-140 °C, and can also be 120-130 °C; the drying time can be 2-3 h. The present invention has no special limitation on the specific model and source of the drying oven, and a commercially available drying oven well-known to those skilled in the art can be used. By drying in the present invention, the ball milling medium can be removed.

[0033] In the present invention, the particle size of the mixed powder is preferably ≤ 75 μm; the moisture content of the mixed powder is preferably ≤ 2%.

[0034] After obtaining the mixed powder, the present invention mixes the mixed powder, a binder and water and then granulates to obtain green balls.

[0035] In the present invention, the binder is preferably sodium-based bentonite; the mass of the binder is preferably 3-8%, more preferably 4-7%, and further preferably 5-6% of the mass of the mixed powder. By adding the binder, the present invention can ensure that the raw materials are bonded into a mass for granulation.

[0036] In the present invention, the mass percentage of water in the green balls is preferably 10-18%. As an embodiment of the present invention, the mass percentage of water in the green balls can be 11%, 12%, 13%, 14%, 15%, 16% or 17%. By controlling the amount of water used, the present invention can avoid deformation of the shape of the green balls caused by excessive water content.

[0037] The present invention has no special limitation on the specific operation of the granulation, and the granulation can be carried out in a manner well-known to those skilled in the art. As an embodiment of the present invention, the granulation can be carried out in a granulator; the extrusion pressure of the granulation can be 10-20 MPa, and can also be 15 MPa; the model of the granulator can be ZL-200.

[0038] In the present invention, the particle size of the green balls is preferably 5-10 mm, more preferably 6-8 mm.

[0039] After obtaining the green balls, the present invention dries and calcines the green balls in sequence to obtain ceramsite.

[0040] In the present invention, the drying is preferably carried out in a drying oven. The present invention has no special limitation on the specific model and source of the drying oven, and a commercially available drying oven well-known to those skilled in the art can be used. By drying, the present invention can remove the water in the green balls and avoid the generation of a large amount of air in the ceramsite due to the evaporation of water during the calcination process, thereby further improving the mechanical properties of the ceramsite.

[0041] In the present invention, the calcination is preferably carried out in a calcination furnace. The present invention has no special limitation on the specific model and source of the calcination furnace, and a commercially available calcination furnace well-known to those skilled in the art can be used.

[0042] In the present invention, the calcination is preferably carried out by first heating at a heating rate of 5 - 15 °C / min to 400 - 600 °C for preheating for 20 - 60 min, and then heating at a heating rate of 15 - 30 °C / min to 1000 - 1400 °C for calcination for 30 - 60 min. More preferably, it is first heated at a heating rate of 10 - 12 °C / min to 450 - 500 °C for preheating for 30 - 40 min, and then heated at a heating rate of 20 - 25 °C / min to 1000 - 1400 °C for calcination for 40 - 50 min. By controlling the parameters of the calcination, the present invention can further improve the mechanical properties of the ceramsite. At the same time, the energy consumption during the calcination process can be reduced by 15 - 20% compared with that of traditional clay ceramsite, saving energy and reducing production costs, meeting the requirements of green and low-carbon production.

[0043] The present invention has no special limitation on the cooling method after the calcination, and it can be determined according to the common technical knowledge of those skilled in the art. As an embodiment of the present invention, the cooling method after the calcination can be natural cooling or furnace cooling.

[0044] In the present invention, the density of the ceramsite is preferably ≤ 1.2 g / cm 3 , more preferably ≤ 1.1 g / cm 3 ; the compressive strength of the ceramsite is preferably ≥ 10 MPa; the porosity of the ceramsite is preferably 15 - 20%. The ceramsite obtained by the present invention has a low density, meeting the lightweight requirements of ocean engineering; at the same time, it has a high compressive strength (traditional solid waste-based aggregate < 5 MPa), which can significantly improve the bearing capacity of marine concrete; at the same time, it has a low porosity (traditional coal gangue aggregate > 30%), which can reduce the water absorption rate (≤ 5%) and improve the frost resistance of marine concrete.

[0045] After obtaining the ceramsite, the present invention impregnates the ceramsite in liquid paraffin under vacuum to obtain a solid waste-based phase change energy storage lightweight aggregate.

[0046] In the present invention, the liquid paraffin is preferably commercially available paraffin or recycled paraffin.

[0047] As an embodiment of the present invention, the preparation method of the liquid paraffin preferably includes: preliminarily removing impurities from waste candles, and then successively carrying out melting, filtering and static stratification to collect the upper-layer liquid paraffin to obtain the liquid paraffin. By using waste candles to prepare liquid paraffin, the present invention can realize the resource utilization of waste candles and reduce production costs.

[0048] The present invention has no special limitation on the specific operation of the preliminary impurity removal, and it can be determined according to the common technical knowledge of those skilled in the art, as long as impurities such as wicks and labels can be removed. As an embodiment of the present invention, the preliminary impurity removal can be magnetic separation.

[0049] The present invention has no special limitation on the melting temperature, which is determined according to the common technical knowledge of those skilled in the art and can enable the candle to melt. As an embodiment of the present invention, the melting temperature can be 80-85°C.

[0050] In the present invention, the filtration is preferably carried out using a filter screen; the filter screen is preferably a 200-mesh filter screen. The present invention can further remove impurities through filtration.

[0051] The present invention has no special limitation on the specific operation of statically separating and collecting the upper-layer liquid paraffin, which can be determined according to the common technical knowledge of those skilled in the art. In the present invention, during the cooling process of the molten wax liquid, due to the differences in physical properties such as density between paraffin and other components, the two will gradually separate, and the liquid paraffin will be in the upper layer. Collecting the upper-layer liquid paraffin can obtain pure liquid paraffin.

[0052] In the present invention, the purity of the liquid paraffin is preferably ≥95%.

[0053] In the present invention, the vacuum impregnation is preferably carried out in a vacuum tank. The present invention has no special limitation on the specific model and source of the vacuum tank, and a commercially available vacuum tank well-known to those skilled in the art can be used.

[0054] In the present invention, the temperature of the vacuum impregnation is preferably 80-85°C. By controlling the temperature of the vacuum impregnation, the present invention can ensure that the paraffin always remains in a liquid state.

[0055] In the present invention, the method of vacuum impregnation is preferably to immerse the ceramsite in the liquid paraffin, then evacuate for 0.5-2 h, and the degree of vacuum during evacuation is -0.1 to -0.05 MPa. Subsequently, release the vacuum and let the ceramsite continue to soak in the liquid paraffin for 1-2 h. More preferably, immerse the ceramsite in the liquid paraffin, then evacuate for 1-1.5 h, and the degree of vacuum during evacuation is -0.08 to -0.06 MPa. Subsequently, release the vacuum and let the ceramsite continue to soak in the liquid paraffin for 1.5-1.8 h. Through vacuum impregnation, the present invention can make the liquid paraffin enter the pores of the ceramsite by means of the negative pressure effect. After releasing the vacuum and then soaking, it can ensure that the pores of the ceramsite can be filled with paraffin.

[0056] In the present invention, the adsorption rate of the liquid paraffin during vacuum impregnation is preferably 15-20%, and more preferably 16-18%. By controlling the adsorption rate of the liquid paraffin, the present invention can further improve the performance of the subsequent marine engineering concrete.

[0057] After the vacuum impregnation is completed, the present invention preferably takes out the product of the vacuum impregnation, wipes off the residual liquid paraffin on the surface, and then dries it to obtain the solid waste-based phase change energy storage lightweight aggregate. The present invention has no special limitation on the specific operation of the wiping, as long as the residual liquid paraffin on the surface can be removed. In the present invention, the drying temperature is preferably 70-80 °C.

[0058] By means of vacuum impregnation, the present invention can achieve a paraffin adsorption rate of 15-20% (only 5%-10% for the direct blending method), and there is no leakage risk; the latent heat of phase change of the solid waste-based phase change energy storage lightweight aggregate is increased by more than 40% (the latent heat of paraffin is about 200-250 J / g), which can effectively buffer temperature fluctuations and reduce thermal stress cracks; when the solid waste-based phase change energy storage lightweight aggregate is used in marine concrete, the thermal conductivity of the marine concrete can be reduced by 30-40%, improving the heat insulation performance and prolonging the structural durability.

[0059] For the preparation method provided by the present invention, the processing cost of the raw materials is reduced by more than 50% (compared with the microcapsule process); at the same time, the raw material cost is saved by 40-60% (the price of natural sand and gravel is about 80-120 yuan / ton, and the cost of the solid waste raw materials is almost zero).

[0060] The present invention uses solid wastes such as coal gangue and fly ash as raw materials to prepare ceramsite. By compounding coal gangue and fly ash, the mechanical properties such as the mechanical strength of the ceramsite can be improved, so that it is more suitable for marine concrete. Then, liquid paraffin is injected into the ceramsite interior by means of vacuum impregnation, which can significantly improve the frost heaving resistance, temperature stress resistance and impact resistance of marine concrete. Through the three core innovations of solid waste resource utilization, lightweight and high-strength aggregate preparation, and phase change energy storage function integration, the present invention systematically solves the problems of single material performance, high consumption and low efficiency of the process, and insufficient function integration in the prior art. The preparation method provided by the present invention not only promotes the resource utilization of solid wastes, reduces the environmental burden, and provides a new technical path for the efficient utilization of solid wastes, but also improves the heat insulation performance and durability of marine concrete, and has been significantly improved in terms of environmental protection, economy and functionality. The preparation method provided by the present invention has a simplified process flow, does not require complex chemical synthesis steps, and is suitable for industrial production.

[0061] The present invention also provides a solid waste-based phase change energy storage lightweight aggregate prepared by the preparation method described in the above technical solution.

[0062] After the solid waste-based phase change energy storage lightweight aggregate provided by the present invention is applied to marine engineering concrete, compared with aggregates such as natural sand and gravel, the self-weight of the marine engineering concrete is reduced by 20-30%, significantly reducing the load on the foundation of the marine structure. At the same time, the thermal stability of the marine engineering concrete is improved, and the temperature difference adaptation range is expanded to -30°C to 60°C (the traditional concrete is -10°C to 50°C). In addition, the chloride ion permeability resistance of the marine engineering concrete can be increased by 50%, extending the service life of the structure in the marine environment.

[0063] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work shall fall within the protection scope of the present invention.

[0064] Example 1

[0065] A preparation method of a solid waste-based phase change energy storage lightweight aggregate applied to marine engineering concrete comprises the following steps:

[0066] (1) Crush the coal gangue in a jaw crusher (model PE-400×600) to obtain coal gangue particles with a particle size ≤ 5 cm. Then mix the coal gangue particles and fly ash and conduct ball milling in a ball mill (model MQG1500×3000). Finally, dry at 120°C for 2 h to obtain a mixed powder with a moisture content ≤ 2% and a particle size ≤ 75 μm. By mass percentage, the mixed powder is 70% coal gangue particles and 30% fly ash;

[0067] (2) Mix the mixed powder obtained in step (1), sodium-based bentonite and water, and conduct granulation in a granulator (model ZL-200). The extrusion pressure for granulation is 15 MPa to obtain green balls with a particle size of 5-10 mm. The mass of the binder is 5% of the mass of the mixed powder; the mass percentage of water in the green balls is 14%;

[0068] (3) Dry the green balls obtained in step (2) in a drying oven and then conduct calcination in a calcination furnace. The calcination is to first heat up to 500°C at a heating rate of 10°C / min and preheat for 30 min, and then heat up to 1200°C at a heating rate of 20°C / min and calcine for 40 min. After natural cooling to room temperature, ceramsite is obtained. The density of the ceramsite is 1.1 g / cm 3 ; the compressive strength of the ceramsite is 12 MPa

[0069] (4) Put liquid paraffin into a vacuum tank, carry out vacuum impregnation of the ceramsite obtained in step (3) in the liquid paraffin, wipe off the residual liquid paraffin on the surface after taking it out, and finally dry it in hot air at 80 °C to obtain solid waste-based phase change energy storage lightweight aggregate;

[0070] The preparation method of the liquid paraffin is as follows: preliminarily remove impurities from waste candles by magnetic separation, then crush and heat them to 85 °C for melting, filter through a 200-mesh filter screen, and finally let it stand for stratification to collect the upper-layer liquid wax to obtain liquid paraffin with a purity ≥ 95%;

[0071] The temperature of the vacuum impregnation is 80 °C; the method of vacuum impregnation is to immerse the ceramsite in the liquid paraffin, then evacuate for 1 h, the degree of vacuum during evacuation is -0.08 MPa, and then release the vacuum to let the ceramsite continue to soak in the liquid paraffin for 1.5 h; the adsorption rate of the liquid paraffin during the vacuum impregnation is 18%.

[0072] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A preparation method of solid waste-based phase change energy storage lightweight aggregate for marine concrete, comprising the following steps: (1) Mix coal gangue particles and fly ash and then perform ball milling to obtain a mixed powder; (2) Mix the mixed powder obtained in step (1), a binder and water and then granulate to obtain green pellets; (3) Dry and calcine the green pellets obtained in step (2) in sequence to obtain ceramsite; (4) Vacuum impregnate the ceramsite obtained in step (3) in liquid paraffin to obtain solid waste-based phase change energy storage lightweight aggregate.

2. The preparation method according to claim 1, characterized in that, In step (1), the particle size of the coal gangue particles ≤ 5 cm.

3. The preparation method according to claim 1, characterized in that, By mass percentage, the mixed powder in step (1) includes 60 - 80% of coal gangue particles and 20 - 40% of fly ash.

4. The preparation method according to claim 1, characterized in that, In step (1), the particle size of the mixed powder ≤ 75 μm.

5. The preparation method according to claim 1, characterized in that, In step (2), the binder is sodium-based bentonite and magnesium oxide; the mass of the binder is 3 - 8% of the mass of the mixed powder.

6. The preparation method according to claim 1, wherein In step (2), the mass percentage of water in the green pellets is 10 - 18%.

7. The preparation method according to claim 1, characterized in that, In step (2), the particle size of the green pellets is 5 - 10 mm.

8. The preparation method according to claim 1, characterized in that, In step (3), the calcination is to first heat up at a heating rate of 5 - 15 °C / min to 400 - 600 °C for preheating for 20 - 60 min, and then heat up at a heating rate of 15 - 30 °C / min to 1000 - 1400 °C for calcination for 30 - 60 min.

9. The preparation method according to claim 1, characterized in that, In step (4), the way of vacuum impregnation is to immerse the ceramsite in liquid paraffin, then evacuate for 0.5 - 2 h, the vacuum degree of evacuation is -0.1 - -0.05 MPa, and then release the vacuum, and let the ceramsite continue to soak in liquid paraffin for 1 - 2 h.

10. The solid waste-based phase change energy storage lightweight aggregate for marine concrete prepared by the preparation method according to any one of claims 1 - 9.