Solid waste-based phase change aggregate and preparation method thereof

Abstract

The invention discloses a solid waste-based phase change aggregate and a preparation method thereof. The solid waste-based phase change aggregate is composed of a solid waste-based porous skeleton, a phase change material and a packaging layer, the phase change material is located in the porous framework, and the solid waste-based porous framework is wrapped by the packaging layer; the solid waste-based porous framework is prepared from the following raw materials in parts by weight: 16-36 parts of lithium slag, 40-60 parts of fly ash, 16-36 parts of yellow phosphorus slag, 4-18 parts of aluminum ash, 30-40 parts of water and 0.5-2 parts of a polycarboxylic acid high-efficiency water reducing agent; the ratio of the lithium slag to the yellow phosphorus slag is (20: 30)-(30: 20); the phase change material is a phase change energy storage material. The solid waste-based phase change aggregate has excellent heat storage capacity and mechanical property.

Description

Technical Field

[0001] This invention belongs to the field of concrete technology, specifically relating to a solid waste-based phase change aggregate and its preparation method. Background Technology

[0002] The large-scale disposal and high-value utilization of industrial solid waste are crucial for promoting green industrial development and achieving the goal of "zero-waste cities." Traditional treatment methods (such as stockpiling or landfilling) not only occupy land and pose environmental risks but also result in serious resource waste. How to transform these solid wastes into high-performance, functional, and advanced building materials through technological innovation has become an important research topic in the field of resources and environment. On the other hand, optimizing energy consumption in infrastructure construction and operation is a crucial step in reducing total social energy consumption and advancing the "dual-carbon" goal. Phase change energy storage technology utilizes the property of materials to absorb or release large amounts of latent heat during phase change, effectively mitigating heat exchange fluctuations between structures and the environment. In civil engineering, water conservancy projects, and transportation construction, this technology can effectively regulate the thermal performance of structures and facilities, optimize the local thermal environment, enhance structural durability, and improve user comfort, making it a promising active thermal control method. However, most phase change materials are liquid in the molten state. If directly combined with cementitious matrices, they are prone to leakage during pouring and service, and will also significantly weaken the mechanical properties of concrete. Therefore, existing technologies typically employ porous carriers to adsorb or coat phase change materials, thereby preparing phase change energy storage aggregates or phase change mortars that can be directly incorporated into concrete to address the leakage problem of phase change materials and improve their compatibility with the matrix.

[0003] Among existing published patents, one type of technical solution mainly utilizes natural porous aggregates as carriers for phase change materials, preparing phase change aggregates through vacuum impregnation or atmospheric pressure impregnation. Patent application CN120829266A discloses a method for preparing composite phase change concrete, including the preparation of a composite phase change aggregate. This composite phase change aggregate uses expanded vermiculite as a porous carrier, loading methyl palmitate and methyl stearate into the pores of expanded vermiculite through vacuum impregnation, followed by surface encapsulation to form a core-shell structure, thereby effectively inhibiting leakage of the phase change material. However, vermiculite, as a natural mineral resource, has limited reserves, and its mining process causes certain damage to the ecological environment, which is inconsistent with the concept of sustainable development. Furthermore, to achieve effective leakage prevention, additional surface coating and encapsulation with organic polymers such as epoxy resin or styrene-acrylic emulsion are required. This step not only increases raw material costs and process complexity, but the polymer encapsulation layer may also face aging risks in long-term humid and hot / cold alternating environments, thus affecting overall durability.

[0004] Another type of technology attempts to achieve a resource-based "waste-to-waste" approach by using industrial solid waste as a carrier. Patent application CN120622832A discloses a method for preparing fly ash-based inorganic phase change thermal storage aggregate based on solid waste utilization. This method uses sodium alginate gel spheres as templates, prepares hollow fly ash spheres through a high-temperature sintering process, and carries inorganic hydrated salt phase change materials. This approach also faces limitations. First, its preparation process is extremely complex, involving multiple delicate steps such as gel sphere making, high-temperature sintering, vacuum impregnation, low-temperature freezing, and multi-layer coating, requiring sophisticated equipment and control, which is not conducive to large-scale production. Second, the sintering temperature of over 1200℃ results in huge energy consumption, compromising both economic efficiency and environmental friendliness. Furthermore, while the complex multi-layer encapsulation process improves leakage prevention performance, it also significantly increases production and time costs, and since the main raw material is only fly ash, its capacity for co-processing other bulk solid wastes is limited.

[0005] In recent years, the preparation of porous aggregates from industrial solid waste has become a research hotspot, with advantages including "waste-to-waste" treatment and low cost. However, existing technologies mostly focus on the utilization of single solid wastes, making it difficult to adapt to the synergistic resource utilization needs of complex solid waste systems. Furthermore, high-energy-consuming preparation processes and packaging stability issues still restrict its engineering application. Therefore, developing a low-energy-consuming phase change energy storage aggregate preparation technology that synergistically utilizes multi-source solid waste is of great significance for promoting the high-end and functional development of solid waste resource utilization. Simultaneously, this technology also provides a solution for constructing low-cost, high-performance, and green low-carbon new energy storage systems, meeting both urgent practical needs and broad application prospects. Summary of the Invention

[0006] This invention provides a solid waste-based phase change aggregate that possesses both excellent heat storage capacity and mechanical properties.

[0007] This invention provides a solid waste-based phase change aggregate, which is composed of a solid waste-based porous framework, a phase change material, and an encapsulation layer. The phase change material is located within the solid waste-based porous framework, and the encapsulation layer encapsulates the solid waste-based porous framework. The raw material composition of the solid waste-based porous framework is 16-36 parts lithium slag, 40-60 parts fly ash, 16-36 parts yellow phosphorus slag, 4-18 parts aluminum ash, 30-40 parts water, and 0.5-2 parts polycarboxylate superplasticizer; the ratio of lithium slag to yellow phosphorus slag is 20:30-30:20; the phase change material is a phase change energy storage material.

[0008] The solid waste-based porous framework provided by this invention is based on the construction of a ternary solid waste-based hypersulfate synergistic activation system using appropriate amounts of yellow phosphorus slag, fly ash, and lithium slag. Through the synergistic effects of each component in ion supply, reaction kinetics regulation, and hydration product generation, cross-linking growth of ettringite and hydrated silicate gel is induced, ultimately forming a porous framework with high structural stability. The specific process is as follows: In the initial stage of the hydration reaction, the glassy structure in the yellow phosphorus slag gradually dissolves, releasing CaO components. 2+ A certain amount of Ca(OH)₂ is generated, causing the pH value of the system to gradually increase, thus forming an alkaline environment. This alkaline environment can promote the dissolution of aluminosilicates in fly ash and lithium slag, releasing aluminosilicate structural units. During this process, the chemical buffering effect of the glassy components of fly ash on alkalinity is utilized to inhibit the early and intense dissolution of yellow phosphorus slag. The aluminosilicate units dissolved from fly ash react with Ca... 2+ The resulting dynamic equilibrium mechanism effectively avoids Ca in the system 2+ The flash coagulation phenomenon caused by increased concentration allows the slurry to maintain good fluidity for a certain period of time, providing the necessary reaction window for the gas-entraining and pore-forming process.

[0009] During the above reaction process, the sulfate minerals in the lithium slag gradually dissolve and release SO4. 2- The reaction produces ettringite crystals. Unlike traditional supersulfate systems where gypsum is directly added externally, sulfates in lithium slag are typically distributed within the particles, and their dissolution process is controlled by the particle structure and diffusion process. Therefore, SO4... 2- The release is more uniform and sustained. This slow-release characteristic makes the formation of ettringite in the system more uniform, enabling the formation of a more uniformly distributed crystal network structure at the microscopic level.

[0010] Li contained in lithium slag + This can lower the dissociation energy of aluminosilicates, increase the dissolution rate of aluminosilicate components, accelerate the formation of hydration products and early high-strength frameworks, thereby improving the hydration reaction kinetics of the system. With the development of Li... + To promote the hydration reaction, SO4 in the system 2- The silicon-aluminum composition can rapidly form short, rod-shaped ettringite crystals. Compared to common needle-shaped ettringite crystals, this crystal structure can better fill the pores of the matrix, thus constructing a stable early framework during the reaction. This framework structure provides support for the pore walls during the alumina gas generation stage, preventing bubbles from merging or collapsing during rise or diffusion, thereby facilitating the formation of a uniform and stable structure.

[0011] In this system, fly ash primarily serves as a source of aluminosilicates. Its glassy aluminosilicate structure gradually hydrolyzes in an alkaline environment, releasing aluminosilicate components. Due to the relatively slow dissolution rate of the aluminosilicate structure in fly ash, its slow-release characteristics reduce the peak instantaneous aluminum ion concentration in the system, thus preventing the rapid formation of ettringite and subsequent hardening of the slurry. Furthermore, the silicon components released from fly ash can participate in the formation of hydrated silicate gels, gradually filling the pores between ettringite crystals in the later stages of the hydration reaction, thereby improving the density of the pore wall structure and the overall strength.

[0012] As the reaction continues, a composite cementitious structure gradually forms in the system, with ettringite as the framework and hydrated silicate gel as the filling phase. The ettringite crystals form an interwoven crystal network within the porous structure, providing early support for the pore walls; while the hydrated silicate gel gradually fills and strengthens this framework in the later stages, further densifying the pore wall structure and thus improving the mechanical properties of the porous material. Because yellow phosphorus slag can provide Ca… 2+ In alkaline environments, fly ash provides the main silicon and aluminum components, while lithium slag provides SO4. 2- and Li + This system can maintain a relatively stable ion supply state during the hydration process, enabling ettringite crystals and hydrated silicate gels to be generated in stages and gradually improve their structure.

[0013] The elemental aluminum contained in the appropriate amount of aluminum ash provided by this invention undergoes a chemical degassing reaction in the alkaline environment of the system and releases hydrogen gas. The generated bubbles are encapsulated by the slurry and transformed into uniformly distributed pores as the matrix solidifies and hardens, thereby optimizing the pore structure of the skeleton.

[0014] Preferably, the volume percentage of pores with a pore size of 100 nm to 1000 nm in the solid waste-based porous framework is 46.5% to 48.7%. Within this pore size range, the phase change material can be better loaded, allowing the impregnation rate and leakage rate of the phase change material to reach suitable values.

[0015] Preferably, the raw materials of the encapsulation layer include 1.6 to 3.6 parts of lithium slag, 4 to 6 parts of fly ash, 1.6 to 3.6 parts of yellow phosphorus slag, and 3 to 4 parts of water.

[0016] This invention employs a supersulfate cement system to prepare an encapsulating slurry, which is then used to coat and cure the outer surface of a composite skeleton impregnated with phase change material. After curing on the aggregate surface, the encapsulating slurry forms a continuous and dense outer shell structure, effectively physically encapsulating the composite skeleton and significantly reducing leakage during the thermal melting process of the phase change material. Simultaneously, due to the physical constraint of this dense shell, the phase change aggregate maintains good stability during phase change cycling, preventing adverse effects on the concrete matrix caused by leakage of the phase change material.

[0017] The encapsulation layer used in this invention is a cementitious structure formed after the hardening of the supersulfate cement system. Its main hydration products include ettringite and hydrated calcium aluminosilicate gel, which can maintain good compatibility with the hydration products in the concrete matrix. This helps to improve the density of the interfacial transition zone and enhance the bonding performance between the aggregate and the matrix, thereby effectively improving the mechanical strength of the concrete. Simultaneously, the dense encapsulation layer provides a certain barrier against moisture and external corrosive media, slowing down the erosion and deterioration process of phase change materials by environmental factors. This improves the durability of the phase change aggregate and ensures that it maintains stable heat storage and release performance under long-term service conditions.

[0018] Preferably, the phase change energy storage material is an organic phase change material and / or an inorganic phase change material, wherein the organic phase change material includes one or more of paraffin wax, fatty acids, fatty alcohols, and polyethylene glycol; and the inorganic phase change material includes one or more of inorganic hydrates and molten salts.

[0019] Preferably, the phase change material loading is 10.0%~13.2%, which ensures high heat storage capacity while not significantly affecting mechanical properties, thus ensuring the structural stability of the aggregate during thermal cycling.

[0020] On the other hand, the present invention also provides a method for preparing the solid waste-based phase change aggregate, comprising: Step S1, Raw material pretreatment: The lithium slag, fly ash, yellow phosphorus slag and aluminum ash are dried, crushed and ground respectively; Step S2: Preparation of solid waste-based porous skeleton: The raw materials of the solid waste-based porous skeleton are proportioned and stirred evenly according to the proportions of each component. Polycarboxylate superplasticizer and water are added and stirred thoroughly to form a uniform slurry. Then, the slurry is allowed to stand for curing, mechanically crushed, and screened to obtain coarse and fine aggregates. The coarse and fine aggregates are cured again to obtain the solid waste-based porous skeleton. Step S3, Phase Change Material Impregnation: The solid waste-based porous framework is dried and vacuumed. Molten phase change material is then impregnated into the solid waste-based porous framework and cooled to room temperature, so that the phase change material is solidified in the pores and stably loaded in the framework. Step S4, Surface encapsulation treatment: The encapsulation layer is wrapped around the solid waste-based porous skeleton obtained in step S3, and dried to obtain solid waste-based phase change aggregate.

[0021] Preferably, the impregnation rate of phase change material in the solid waste-based porous framework is 82.6%~85.2%, and the leakage rate is 14.2%~15.1%.

[0022] Preferably, in step S2, a natural stone crusher is used to perform mechanical crushing.

[0023] Preferably, in step S2, the aggregate is sieved through sieves with apertures of 20 mm, 4.75 mm and 2.36 mm in sequence to obtain coarse aggregate with a particle size of 4.75~20 mm and fine aggregate with a particle size of 2.36~4.75 mm, so as to meet different gradation requirements.

[0024] Preferably, the encapsulation layer contains solid waste raw materials and water, wherein the mass ratio of lithium slag, fly ash, and yellow phosphorus slag is 20:50:30~30:50:20, and the water-ash ratio is 0.3~0.4. The raw materials are ground and mixed, then mixed with a measured amount of water to form a slurry for encapsulation, ensuring a dense and uniform encapsulation layer.

[0025] Preferably, in step S3, a vacuum is drawn to -0.08 to -0.05 MPa for 2 to 3 hours, and the molten phase change material is immersed in the solid waste-based porous framework for 30 to 120 minutes.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows: This study synergistically constructed a supersulfate cement system using fly ash, yellow phosphorus slag, and lithium slag. Fly ash, as the primary aluminosilicate framework material, provided abundant silica and alumina components for the system; yellow phosphorus slag released calcium... 2+ This process creates an alkaline environment within the system, promoting the dissolution of aluminosilicates and further generating hydration products such as ettringite crystals and hydrated aluminosilicate gels. Simultaneously, the lithium slag replenishes the aluminosilicate components in the system and provides a necessary source of sulfates, achieving a multi-component synergistic reaction. Furthermore, the Li contained in the lithium slag... + It has a significant promoting effect on the hydration kinetics of the hypersulfate system. Li + This can lower the dissociation energy of aluminosilicates, thereby significantly improving the dissolution efficiency of the aluminosilicate component and further accelerating the formation rate of hydration products, thus forming a high-strength framework structure in the early stages of the system. Due to Li... + Due to the promoting effect of [the process], ettringite crystals in the system typically precipitate in the form of short rod-shaped crystals. This crystal morphology possesses excellent pore-filling and structural cross-linking capabilities, enabling it to more effectively fill micropores in the matrix and strengthen the pore wall structure, thereby significantly improving the mechanical properties of phase change aggregates. Simultaneously, the short rod-shaped ettringite crystals can further refine the macroporous structure, transforming it more into pore structures of 100–1000 nm, thus better limiting the leakage of phase change materials.

[0027] Meanwhile, this invention utilizes aluminum ash as a pore-forming agent. Through the chemical reaction of aluminum ash in an alkaline environment, gases are released, forming a rich porous structure within the solid waste-based framework, providing ample space for the loading of phase change materials (PCMs). The introduction of aluminum ash not only significantly enhances the thermal storage capacity of the energy storage aggregate but also, by optimizing the pore structure, enables the aggregate to maintain high mechanical strength while retaining high porosity and PCM loading rate, achieving synergistic optimization of thermal and mechanical properties. The resulting solid waste-based PCM aggregate, while maintaining a high PCM loading rate, still possesses excellent compressive strength and can be used as a lightweight aggregate for PCM energy storage, thereby realizing the high-value resource utilization of industrial solid waste. Attached Figure Description

[0028] Figure 1 Pore ​​volume distribution diagrams of the porous frameworks prepared in Examples 1-3 and Comparative Examples 1-4; Figure 2 The image shows the morphology of short rod-shaped ettringite crystals generated in the ternary solid waste-based porous framework prepared in Example 1. Figure 3 This is a flowchart of the preparation process of solid waste-based phase change aggregate obtained in Example 4 of the present invention. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It should be noted that the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention.

[0030] This invention uses industrial solid wastes such as lithium slag, fly ash, yellow phosphorus slag, and aluminum ash as raw materials. Fly ash serves as the main aluminosilicate component, yellow phosphorus slag provides an alkaline activation environment for the reaction, lithium slag primarily provides sulfate activation components and some aluminosilicates, and aluminum ash acts as a pore-forming agent, releasing gas under alkaline activation conditions to regulate the pore structure. Therefore, through the synergistic effect of multiple components, a framework with both excellent mechanical strength and abundant pore structure is formed. Vacuum impregnation technology is used to fully fill the pore structure with organic or inorganic phase change materials, endowing the aggregate with significant thermal energy storage capacity. Finally, the aggregate impregnated with phase change materials undergoes encapsulation treatment to improve the shaping ability of the phase change materials, thereby preparing solid waste-based phase change aggregates with excellent thermal storage performance and good mechanical properties. This process achieves the goal of high-value utilization of solid waste and structural-functional integration.

[0031] The solid waste-based phase change aggregate prepared by this invention exhibits excellent heat storage performance and good mechanical strength. The aggregate matrix comprises lithium slag, fly ash, yellow phosphorus slag, and aluminum ash. To reveal the influence of mix proportions and the mechanism by which the amount of aluminum ash affects aggregate performance, this invention designs a series of embodiments and comparative examples. By adjusting the ratio of lithium slag to yellow phosphorus slag, the optimal porosity range and optimal mix proportion of the impregnated phase change material are obtained. Then, by adjusting the amount of aluminum ash added, and testing the compressive strength and latent heat of phase change of aggregates with different mix proportions, the effects of each raw material and mix proportion on the formation of the porous framework, the load-bearing capacity of the phase change material, and the comprehensive performance of the heat storage aggregate are evaluated, providing experimental evidence for the rationality and superiority of the technical solution of this invention.

[0032] Example 1 This invention provides a method for preparing a phase change material loaded within a solid waste-based porous framework, comprising: the solid waste-based porous framework being composed of the following raw materials in parts by weight: 20 parts lithium slag, 30 parts yellow phosphorus slag, 50 parts fly ash, 5 parts aluminum ash, 35 parts water, and 1 part polycarboxylate superplasticizer. The preparation method of the solid waste-based porous framework includes the following steps: Step S1, Raw material pretreatment: The lithium slag, fly ash, yellow phosphorus slag and aluminum ash are dried, crushed and ground respectively.

[0033] Step S2: Preparation of the porous skeleton based on solid waste: Lithium slag, fly ash, yellow phosphorus slag, and aluminum ash are weighed according to predetermined mass proportions and mixed evenly in a mixing device. Then, a certain amount of polycarboxylate superplasticizer and water are added and stirred thoroughly to form a uniform slurry. The slurry is then poured into a mold for molding and allowed to stand at room temperature for 24 hours before demolding. The demolded sample is mechanically crushed and sieved to obtain coarse and fine aggregates.

[0034] Step S3, Curing and Molding: Place the obtained coarse and fine aggregates in an oven at 60℃ for 5 days to obtain a porous skeleton based on solid waste.

[0035] Then, the phase change material is loaded onto the solid waste-based porous framework by vacuum impregnation, as shown in step S4 below.

[0036] Step S4, Phase Change Material Impregnation: Industrial paraffin wax was selected as the phase change material used in this embodiment. The solid waste-based porous skeleton was pretreated in a vacuum drying oven at 60°C for 2 hours, and then placed in a vacuum impregnation device. The vacuum was evacuated to -0.08 MPa for 2 hours to remove air from the aggregate pores. Then, under vacuum, industrial paraffin wax heated to 60°C was slowly injected into the device and impregnated for 60 minutes. Subsequently, it was naturally cooled to room temperature to allow the phase change material to solidify in the pores and be stably loaded in the skeleton.

[0037] Preferably, in step S3, a natural stone crusher is used to perform mechanical crushing.

[0038] Preferably, in step S3, the aggregate is sieved through sieves with apertures of 20 mm, 4.75 mm and 2.36 mm in sequence to obtain coarse aggregate with a particle size of 4.75~20 mm and fine aggregate with a particle size of 2.36~4.75 mm, so as to meet different gradation requirements.

[0039] Example 2 Unlike Example 1, the solid waste-based porous framework in this example is composed of the following raw materials in parts by weight: 25 parts lithium slag, 25 parts yellow phosphorus slag, 50 parts fly ash, 5 parts aluminum ash, 35 parts water, and 1 part polycarboxylate superplasticizer.

[0040] Example 3 Unlike Example 1, the porous skeleton based on solid waste in this example is composed of the following raw materials in parts by weight: 30 parts lithium slag, 20 parts yellow phosphorus slag, 50 parts fly ash, 5 parts aluminum ash, 35 parts water and 1 part polycarboxylate superplasticizer.

[0041] Comparative Example 1 Unlike Example 1, the solid waste-based porous framework in this comparative example is composed of the following raw materials in parts by weight: 40 parts lithium slag, 10 parts yellow phosphorus slag, 50 parts fly ash, 5 parts aluminum ash, 35 parts water, and 1 part polycarboxylate superplasticizer.

[0042] Comparative Example 2 Unlike Example 1, the solid waste-based porous framework in this comparative example is composed of the following raw materials in parts by weight: 50 parts lithium slag, 50 parts fly ash, 5 parts aluminum ash, 35 parts water, and 1 part polycarboxylate superplasticizer.

[0043] Comparative Example 3 Unlike Example 1, the solid waste-based porous skeleton in this comparative example is composed of the following raw materials in parts by weight: 50 parts yellow phosphorus slag, 50 parts fly ash, 5 parts aluminum ash, 35 parts water, and 1 part polycarboxylate superplasticizer.

[0044] Comparative Example 4 Unlike Example 1, the solid waste-based porous framework in this comparative example is composed of the following raw materials in parts by weight: 10 parts lithium slag, 40 parts yellow phosphorus slag, 50 parts fly ash, 5 parts aluminum ash, 35 parts water, and 1 part polycarboxylate superplasticizer.

[0045] To investigate the influence of the ratio of lithium slag to yellow phosphorus slag on the performance of a porous skeleton based on solid waste, this embodiment first characterized the pore size distribution of each group of samples using mercury intrusion porosimetry while keeping the content of fly ash and aluminum ash constant. Subsequently, the impregnation rate of the phase change material (PCM) was calculated by weighing the mass change of the porous skeleton before and after impregnation with industrial paraffin. To further evaluate the encapsulation stability of the PCM on the PCM, the composite skeleton loaded with PCM was placed in a 70°C environment for 3 hours for constant temperature treatment. After removal, the residue seeping from its surface was wiped with filter paper, and a second weighing was performed to calculate the leakage rate of each group of samples. The test results and comparative data of the above properties are detailed in Table 1.

[0046] Table 1. Phase change material impregnation rate and leakage rate of the composite skeletons prepared in each embodiment and comparative example. Note: (1) Impregnation rate: refers to the percentage of the volume of phase change material actually loaded in the porous skeleton to the theoretically fillable pore volume inside the skeleton; (2) Leakage rate: refers to the percentage of the volume of phase change material leaking from the skeleton at a temperature of 70°C to the theoretically fillable pore volume inside the skeleton.

[0047] Table 1 shows that different formulations exhibit significant differences in impregnation rate and leakage rate of the phase change material. The composite skeletons prepared in Examples 1-3 have higher impregnation rates, significantly higher than those in Comparative Examples 1-4; simultaneously, their leakage rates are all below 15.1%, significantly lower than the leakage levels in Comparative Examples 1-4. These results indicate that the porous skeletons formed under the conditions of Examples 1-3 can provide good confinement for the molten phase change material. Combined with the results of mercury intrusion porosimetry pore size distribution testing (… Figure 1 It can be further inferred that the pore size of the composite frameworks prepared in Examples 1 to 3 is mainly concentrated in the range of 100 to 1000 nm, while the proportion of Comparative Examples 1 to 4 in this pore size range is relatively low. This range of pores can provide sufficient storage space for the phase change material and can effectively limit its leakage during the phase change process through capillary action. Therefore, 100 to 1000 nm is the preferred pore size range.

[0048] In Examples 1-3, when the ratio of lithium slag to yellow phosphorus slag was 20:30 to 30:20, the aforementioned excellent pore structure could be constructed. This is primarily due to the regulatory mechanism of lithium slag within the ternary synergistic activation system. Lithium slag not only provides sulfates, but also contains Li... + In an alkaline environment, it can exert a significant polarization effect on water molecules and dissolved ions in the solution. This polarization effect can enhance the solubility of silicon-aluminum components and sulfate components in the system, thereby rapidly constructing a high-strength matrix framework in the early stages of the reaction. This is achieved by using Li...+ The induced, highly efficient excitation mechanism, combined with the slow-release properties of sulfate, fundamentally altered the microstructure of the generated ettringite crystals, transforming them from elongated needle-like structures into short rod-like crystals (see...). Figure 2 At the microstructural level, short rod-shaped ettringite exhibits higher pore-filling efficiency and structural cross-linking ability compared to elongated crystals, enabling it to more effectively fill micropores in the matrix and thus optimize the pore wall structure. This morphological feature allows for further segmentation and regulation of the pore structure, transforming previously easily interconnected coarse pores into refined pore structures of approximately 100–1000 nm. Lithium slag, by providing a continuous source of sulfate and promoting the dissolution of silicon and aluminum components, can regulate the micromorphology and pore structure of hydration products, thereby optimizing the pore distribution in the matrix and improving the mechanical stability and thermal storage performance of the framework structure.

[0049] In Comparative Examples 1 to 4, when the lithium slag content was less than 20 parts or greater than 30 parts, and when the yellow phosphorus slag content was greater than 30 parts or less than 20 parts, the sulfate or alkaline environment in the system was insufficient or excessive, affecting the dissolution of aluminosilicates and the formation of ettringite crystals. When the lithium slag content was too high, the excessive sulfate concentration led to the rapid formation of ettringite and the formation of coarse crystal structures, resulting in an uneven pore structure. Conversely, when the lithium slag content was too low or yellow phosphorus slag was lacking, the alkalinity of the system was insufficient, the dissolution of fly ash was limited, the amount of hydration products generated was reduced, and it was difficult to form a stable framework structure. These conditions all led to the development of pores in the radial and macropore directions, thereby reducing the impregnation rate of the phase change material and increasing the leakage rate.

[0050] Therefore, based on the data results, it can be deduced that in Examples 1-3, due to the good synergistic effect formed between lithium slag, fly ash, and yellow phosphorus slag, the lithium... + By promoting hydration reactions and filling with short rod-shaped ettringite crystals, a porous structure with pores in the range of 100~1000 nm was constructed, enabling the porous framework to simultaneously possess high phase change material loading capacity and good encapsulation stability.

[0051] To verify the effect of the ratio of lithium slag to yellow phosphorus slag on the mechanical properties of the prepared composite skeleton, the present invention conducted cylinder compressive strength tests on the samples prepared in the above embodiments and comparative examples; the tests were conducted in accordance with GB / T 17431.2-2010 "Lightweight Aggregates and Their Test Methods".

[0052] Table 2 Compressive strength of the composite skeleton cylinders prepared in each embodiment and comparative example According to the cylinder compressive strength test results shown in Table 2, the composite skeleton cylinder compressive strengths prepared in Examples 1, 2, and 3 are 4.8 MPa, 5.1 MPa, and 5.6 MPa, respectively, all higher than 4.0 MPa, meeting the mechanical performance requirements in practical engineering applications. Therefore, it can be considered that when the ratio of lithium slag to yellow phosphorus slag is within the ranges of 20:30, 25:25, and 30:20, the composite skeleton exhibits optimal mechanical properties, forming the high-strength technical characteristics described in this invention. This can be attributed to the efficient synergistic activation achieved between lithium slag, fly ash, and yellow phosphorus slag within this ratio range. The Li released from the lithium slag... + The polarization effect generated in the alkaline environment significantly enhances the solubility of silicon-aluminum components and sulfates, thereby rapidly building a high-strength matrix framework in the early stages of the reaction.

[0053] Meanwhile, under this ratio, the slow-release properties of sulfate induce the transformation of the hydration product, ettringite, from slender needle-like crystals to short rod-like crystals. This morphological evolution effectively improves the space occupancy efficiency and structural cross-linking ability of the crystals, significantly enhancing the mechanical stability of the pore walls. Conversely, when the ratio of lithium slag to yellow phosphorus slag exceeds the above-mentioned preferred range, as shown in Comparative Examples 2 and 3, the system will experience an imbalance in the hydration process due to insufficient alkalinity or excessive sulfate, resulting in coarse crystal structures or limited crystal production, failing to construct a stable framework support, and ultimately leading to a significant decrease in cylinder compressive strength. In summary, limiting the ratio of lithium slag to yellow phosphorus slag to 20:30~30:20 is the preferred ratio scheme for achieving integrated framework structure and function.

[0054] To verify that the prepared solid waste-based phase change aggregate has good mechanical properties and heat storage capacity under the above raw material ratio, Examples 4 to 12 and Comparative Examples 5 to 8 were set up.

[0055] Example 4 This invention provides a solid waste-based phase change aggregate, which is composed of the following raw materials in parts by weight: 20 parts lithium slag, 30 parts yellow phosphorus slag, 50 parts fly ash, 5 parts aluminum ash, 13.5 parts encapsulation slurry, 35 parts water, and 1 part polycarboxylate superplasticizer. The preparation method of the solid waste-based phase change aggregate is as follows: Figure 3 As shown, it includes the following steps: Step S1, Raw material pretreatment: The lithium slag, fly ash, yellow phosphorus slag and aluminum ash are dried, crushed and ground respectively.

[0056] Step S2: Preparation of the porous skeleton based on solid waste: Lithium slag, fly ash, yellow phosphorus slag, and aluminum ash are weighed according to predetermined mass proportions and mixed evenly in a mixing device. Then, a certain amount of polycarboxylate superplasticizer and water are added and stirred thoroughly to form a uniform slurry. The slurry is then poured into a mold for molding and allowed to stand at room temperature for 24 hours before demolding. The demolded sample is mechanically crushed and sieved to obtain coarse and fine aggregates.

[0057] Step S3, Curing and Molding: Place the obtained coarse and fine aggregates in an oven at 60℃ for 5 days to obtain a porous skeleton based on solid waste.

[0058] Step S4, Phase Change Material Impregnation: Industrial paraffin wax was selected as the phase change material used in this embodiment. The solid waste-based porous skeleton was pretreated in a vacuum drying oven at 60°C for 2 hours, and then placed in a vacuum impregnation device. The vacuum was evacuated to -0.08 MPa for 2 hours to remove air from the aggregate pores. Then, under vacuum, industrial paraffin wax heated to 60°C was slowly injected into the device and impregnated for 60 minutes. Subsequently, it was naturally cooled to room temperature to allow the phase change material to solidify in the pores and be stably loaded in the skeleton.

[0059] Step S5, Surface encapsulation treatment: The outer layer of the aggregate loaded with phase change material is coated with a tight-sealing encapsulation layer composed of lithium slag, fly ash and yellow phosphorus slag, which is wrapped to achieve uniform coverage. After drying and curing, a stable encapsulation layer is formed.

[0060] Preferably, in step S3, a natural stone crusher is used to perform mechanical crushing.

[0061] Preferably, in step S3, the aggregate is sieved through sieves with apertures of 20 mm, 4.75 mm and 2.36 mm in sequence to obtain coarse aggregate with a particle size of 4.75~20 mm and fine aggregate with a particle size of 2.36~4.75 mm, so as to meet different gradation requirements.

[0062] Preferably, the industrial paraffin used in step S4 has a phase transition enthalpy of 202.7 J / g and a phase transition temperature of 27.7℃.

[0063] Preferably, the encapsulation layer contains solid waste materials such as lithium slag, yellow phosphorus slag, and fly ash, as well as water. The mass ratio of lithium slag, fly ash, and yellow phosphorus slag is 2:5:3, and the water-ash ratio is 0.35. After grinding and mixing, the raw materials are mixed with a certain amount of water to form a slurry for encapsulation, ensuring that the encapsulation layer is dense and uniform.

[0064] The aforementioned solid waste-based phase change aggregate can support 18.5 parts of industrial paraffin, with a loading of 10.7%, providing effective support for the thermal energy storage function of the aggregate.

[0065] Example 5 Unlike Example 4, the solid waste-based phase change aggregate in this example is composed of the following raw materials in parts by weight: 20 parts lithium slag, 30 parts yellow phosphorus slag, 50 parts fly ash, 10 parts aluminum ash, 13.5 parts encapsulation slurry, 35 parts water, and 1 part polycarboxylate superplasticizer. The above-mentioned solid waste-based phase change aggregate can support 22.0 parts of industrial paraffin wax, with a loading of 12.1%.

[0066] Example 6 Unlike Example 4, the solid waste-based phase change aggregate in this example is composed of the following raw materials in parts by weight: 20 parts lithium slag, 30 parts yellow phosphorus slag, 50 parts fly ash, 15 parts aluminum ash, 13.5 parts encapsulation slurry, 35 parts water, and 1 part polycarboxylate superplasticizer. The above-mentioned solid waste-based phase change aggregate can support 25.0 parts of industrial paraffin wax, with a loading of 13.2%.

[0067] Example 7 Unlike Example 4, the solid waste-based phase change aggregate in this example is composed of the following raw materials in parts by weight: 25 parts lithium slag, 25 parts yellow phosphorus slag, 50 parts fly ash, 5 parts aluminum ash, 13.5 parts encapsulation slurry, 35 parts water, and 1 part polycarboxylate superplasticizer. The above-mentioned solid waste-based phase change aggregate can support 17.5 parts of industrial paraffin wax, with a loading of 10.2%.

[0068] Example 8 Unlike Example 4, the solid waste-based phase change aggregate in this example is composed of the following raw materials in parts by weight: 25 parts lithium slag, 25 parts yellow phosphorus slag, 50 parts fly ash, 10 parts aluminum ash, 13.5 parts encapsulation slurry, 35 parts water, and 1 part polycarboxylate superplasticizer. The above-mentioned solid waste-based phase change aggregate can support 21.1 parts of industrial paraffin wax, with a loading of 11.7%.

[0069] Example 9 Unlike Example 4, the solid waste-based phase change aggregate in this example is composed of the following raw materials in parts by weight: 25 parts lithium slag, 25 parts yellow phosphorus slag, 50 parts fly ash, 15 parts aluminum ash, 13.5 parts encapsulation slurry, 35 parts water, and 1 part polycarboxylate superplasticizer. The above-mentioned solid waste-based phase change aggregate can support 23.5 parts of industrial paraffin wax, with a loading of 12.5%.

[0070] Example 10 Unlike Example 4, the solid waste-based phase change aggregate in this example is composed of the following raw materials in parts by weight: 30 parts lithium slag, 20 parts yellow phosphorus slag, 50 parts fly ash, 5 parts aluminum ash, 13.5 parts encapsulation slurry, 35 parts water, and 1 part polycarboxylate superplasticizer. The above-mentioned solid waste-based phase change aggregate can support 17.2 parts of industrial paraffin wax, with a loading of 10.0%.

[0071] Example 11 Unlike Example 4, the solid waste-based phase change aggregate in this example is composed of the following raw materials in parts by weight: 30 parts lithium slag, 20 parts yellow phosphorus slag, 50 parts fly ash, 10 parts aluminum ash, 13.5 parts encapsulation slurry, 35 parts water, and 1 part polycarboxylate superplasticizer. The above-mentioned solid waste-based phase change aggregate can support 19.9 parts of industrial paraffin wax, with a loading of 11.1%.

[0072] Example 12 Unlike Example 4, the solid waste-based phase change aggregate in this example is composed of the following raw materials in parts by weight: 30 parts lithium slag, 20 parts yellow phosphorus slag, 50 parts fly ash, 15 parts aluminum ash, 13.5 parts encapsulation slurry, 35 parts water, and 1 part polycarboxylate superplasticizer. The above-mentioned solid waste-based phase change aggregate can support 23.1 parts of industrial paraffin wax, with a loading of 12.3%.

[0073] Comparative Example 5 Unlike Example 4, the solid waste-based phase change aggregate in this comparative example is composed of the following raw materials in parts by weight: 25 parts lithium slag, 25 parts yellow phosphorus slag, 50 parts fly ash, 3 parts aluminum ash, 13.5 parts encapsulation slurry, 35 parts water, and 1 part polycarboxylate superplasticizer. The above-mentioned solid waste-based phase change aggregate can support 16.4 parts of industrial paraffin wax, with a loading of 9.7%.

[0074] Comparative Example 6 Unlike Example 4, the solid waste-based phase change aggregate in this comparative example is composed of the following raw materials in parts by weight: 25 parts lithium slag, 25 parts yellow phosphorus slag, 50 parts fly ash, 20 parts aluminum ash, 13.5 parts encapsulation slurry, 35 parts water, and 1 part polycarboxylate superplasticizer. The above-mentioned solid waste-based phase change aggregate can support 27.1 parts of industrial paraffin wax, with a loading of 13.8%.

[0075] Comparative Example 7 Unlike Example 4, the solid waste-based phase change aggregate in this comparative example is composed of the following raw materials in parts by weight: 20 parts lithium slag, 30 parts yellow phosphorus slag, 50 parts fly ash, 3 parts aluminum ash, 13.5 parts encapsulation slurry, 35 parts water, and 1 part polycarboxylate superplasticizer. The above-mentioned solid waste-based phase change aggregate can support 16.0 parts of industrial paraffin wax, with a loading of 9.5%.

[0076] Comparative Example 8 Unlike Example 4, the solid waste-based phase change aggregate in this comparative example is composed of the following raw materials in parts by weight: 30 parts lithium slag, 20 parts yellow phosphorus slag, 50 parts fly ash, 20 parts aluminum ash, 13.5 parts encapsulation slurry, 35 parts water, and 1 part polycarboxylate superplasticizer. The above-mentioned solid waste-based phase change aggregate can support 26.2 parts of industrial paraffin wax, with a loading of 13.4%.

[0077] The compressive strength and heat storage capacity of the prepared solid waste-based phase change aggregate were tested under different amounts of aluminum ash. The heat storage capacity of the aggregate was determined by differential scanning calorimetry (DSC) to obtain the phase change enthalpy. The test results are shown in Table 3.

[0078] Table 3 Compressive strength and thermal properties of solid waste-based phase change aggregates Analysis of the test results from Examples 4 to 12 after loading phase change material and surface encapsulation shows that the amount of aluminum ash is the core variable determining the heat storage capacity of the aggregate. When the ratio of lithium slag to yellow phosphorus slag is 25:25, as the amount of aluminum ash increases from 5 parts to 15 parts, the loading of industrial paraffin wax on the aggregate increases from 10.2% to 12.5%, and its phase change enthalpy also increases significantly from 20.7 J / g to 25.4 J / g. This fully verifies that the aeration and pore-forming effect of aluminum ash can effectively enrich the loading pore space of the phase change material. However, when the amount of aluminum ash is too high (20 parts), the aggregate can adsorb more phase change material, increasing the heat storage capacity to 28.0 J / g, but the compressive strength of the cylinder drops sharply to 3.4 MPa. When the amount of aluminum ash is too low (3 parts), although the compressive strength of the aggregate cylinder increases significantly to 5.3 MPa, its heat storage capacity decreases to 19.7 J / g.

[0079] To ensure that phase change aggregates maintain high mechanical properties during production, transportation, and use, their compressive strength should be no less than 4 MPa. Simultaneously, to achieve effective heat storage and release, the latent heat value should be higher than 20 J / g to meet the heat storage requirements of most scenarios. Therefore, controlling the aluminum ash content to within the range of 5-15 parts is a key technical measure to ensure that the aggregate possesses high heat storage capacity while maintaining good mechanical properties.

[0080] Therefore, the prepared solid waste-based phase change aggregate, due to its dual structural design of "internal strong skeleton + external dense layer", achieves an optimal balance between mechanical strength and heat storage function in the final product, realizing the high-value transformation of industrial solid waste into high-performance building energy-saving materials.

[0081] The solid waste-based phase change aggregate and its preparation method provided by this invention use industrial solid wastes such as lithium slag, yellow phosphorus slag, fly ash, and aluminum ash as raw materials. Phase change materials are loaded using vacuum impregnation technology, and the aggregate is then coated and encapsulated in a slurry to achieve shaping capability, thus realizing the efficient utilization of solid waste resources and the functional upgrading of aggregates. Its core beneficial effects are reflected in the following aspects: 1. This invention uses various industrial solid wastes such as lithium slag, fly ash, yellow phosphorus slag, and aluminum ash as raw materials. Through scientific proportioning design and synergistic reaction mechanisms, a porous framework structure is constructed. This not only significantly improves the comprehensive utilization rate of solid waste and reduces the environmental pressure caused by stockpiling and landfilling, but also realizes the transformation of waste into high-value-added functional building materials, aligning with the strategic orientation of "zero-waste cities" and "dual-carbon" initiatives.

[0082] 2. This invention introduces lithium slag, utilizing the Li it contains. + In an alkaline environment, the aluminosilicate components in the solution are significantly polarized, thereby accelerating the depolymerization and breakage of silicon (aluminum) oxygen bonds. This allows for the rapid formation of hydration products in the early stages of the reaction, thus constructing a high-strength matrix framework in the early stages. Simultaneously, lithium slag, as a continuous source of sulfate, forms a ternary synergistic activation system with yellow phosphorus slag and fly ash, optimizing the hydration kinetics and enabling the regulation of aluminosilicate dissolution efficiency.

[0083] 3. This invention utilizes Li + The induction and excitation mechanism, in relation to SO4 2- Under the combined action of these factors, the microstructure of the generated ettringite crystals can be altered, transforming them from the traditional slender needle-like structure into short rod-like crystals. Compared to the slender structure, the short rod-like ettringite exhibits a higher porosity filling effect and structural cross-linking ability, enabling it to more effectively fill the micropores of the matrix and strengthen the pore wall structure, thereby significantly improving the overall mechanical stability of the phase change aggregate.

[0084] 4. This invention achieves deep optimization of the matrix pore structure. Short rod-shaped ettringite crystals can further segment and refine the pore structure, transforming the originally easily interconnected coarse pores into a refined pore structure of 100~1000 nm. This optimized pore size distribution not only provides ample storage space for the phase change material, but also effectively limits the migration and leakage of the phase change material through enhanced capillary action, ultimately producing a solid waste-based phase change aggregate with both excellent thermal storage performance and good mechanical strength.

[0085] 5. By introducing aluminum ash as a pore-forming agent, a gas is generated through a reaction in an alkaline environment, forming a rich porous structure. This structure can efficiently load phase change materials, improving heat storage density and phase change enthalpy. Furthermore, through synergistic hydration between solid wastes, a dense skeleton is formed, enabling the aggregate to maintain high porosity while still possessing good compressive strength and durability. This successfully solves the industry challenge of balancing energy storage and mechanical properties.

[0086] 6. The process route, which combines room-temperature molding with mechanical crushing, avoids the high energy consumption problem of traditional high-temperature sintering. Utilizing the material's low early-stage strength for crushing significantly reduces energy consumption and equipment wear. The overall process is simple, highly controllable, and easily scalable for continuous production, aligning with the industrial development trends of green manufacturing and energy conservation.

[0087] 7. The encapsulation layer uses a solid waste-based slurry of the same origin as the skeleton, whose main components are ettringite and hydrated calcium aluminosilicate gel. It has high chemical compatibility with the cement matrix and can effectively enhance the interfacial bonding force of aggregates in the cement matrix. At the same time, the encapsulation layer has a relatively dense structure, which can effectively prevent the leakage of phase change materials and improve the durability and thermal reliability of aggregates.

[0088] 8. By selecting organic or inorganic phase change materials with different phase change temperatures, the heat storage and release characteristics of aggregates can be flexibly controlled. Applying these materials to phase change energy storage concrete or mortar can significantly mitigate temperature fluctuations, reduce building energy consumption, and delay the development of temperature cracks in large-volume concrete, showing broad application prospects in building envelopes, road engineering, and underground engineering.

[0089] 9. The solid waste-based aggregate prepared by this invention not only reduces the dependence on natural aggregates and reduces the ecological damage caused by mining, but can also be used directly as a functional aggregate in concrete preparation to improve its thermal performance.

[0090] In summary, the solid waste-based phase change aggregate prepared by this invention achieves the integrated construction of multi-source synergistic resource utilization of industrial solid waste and aggregate functionalization. Structurally, this aggregate forms a porous skeleton, which can efficiently support phase change materials. In terms of performance, it possesses both good mechanical strength and significant heat storage capacity, effectively overcoming the technical bottlenecks of decreased mechanical performance and easy leakage of traditional phase change materials in concrete applications. This invention not only provides a reliable path for the high-value-added utilization of industrial solid waste but also lays a technical foundation for the development of green cement concrete materials with both thermal regulation and structural load-bearing capacity. It has significant environmental, economic, and engineering application prospects, and helps promote the sustainable development of the building materials industry towards resource conservation, low-carbon environmental protection, and functional composite directions. The basic principles, main features, and advantages of this invention have been shown and described above. Those skilled in the art should understand that this invention is not limited to the above embodiments, and various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of this invention. The scope of this invention is defined by the appended claims and their equivalents.

Claims

1. A solid waste-based phase change aggregate, characterized in that, The solid waste-based phase change aggregate consists of a solid waste-based porous skeleton, a phase change material, and an encapsulation layer. The phase change material is located within the solid waste-based porous framework, and the encapsulation layer encapsulates the solid waste-based porous framework. The raw material composition of the solid waste-based porous framework is 16-36 parts lithium slag, 40-60 parts fly ash, 16-36 parts yellow phosphorus slag, 4-18 parts aluminum ash, 30-40 parts water, and 0.5-2 parts polycarboxylate superplasticizer; the ratio of lithium slag to yellow phosphorus slag is 20:30-30:20; the phase change material is a phase change energy storage material.

2. The solid waste-based phase change aggregate according to claim 1, characterized in that, The volume percentage of pores with a pore size of 100 nm to 1000 nm in the solid waste-based porous framework is 46.5% to 48.7%.

3. The solid waste-based phase change aggregate according to claim 1, characterized in that, The raw materials for the encapsulation layer include 1.6 to 3.6 parts lithium slag, 4 to 6 parts fly ash, 1.6 to 3.6 parts yellow phosphorus slag, and 3 to 4 parts water.

4. The solid waste-based phase change aggregate according to claim 1, characterized in that, The phase change energy storage material is an organic phase change material and / or an inorganic phase change material. The organic phase change material includes one or more of paraffin wax, fatty acids, fatty alcohols, and polyethylene glycol. The inorganic phase change material includes one or more of inorganic hydrates and molten salts.

5. The solid waste-based phase change aggregate according to claim 1, characterized in that, The phase change material loading is 10.0%~13.2%.

6. A method for preparing solid waste-based phase change aggregate according to any one of claims 1-5, characterized in that, include: Step S1, Raw materials Pretreatment: Lithium slag, fly ash, yellow phosphorus slag and aluminum ash are dried, crushed and ground respectively; Step S2: Preparation of solid waste-based porous skeleton: The raw materials of the solid waste-based porous skeleton are proportioned and stirred evenly according to the proportions of each component. Polycarboxylate superplasticizer and water are added and stirred to form a uniform slurry. Then, the slurry is allowed to stand for curing, mechanically crushed, and screened to obtain coarse and fine aggregates. The coarse and fine aggregates are cured again to obtain the solid waste-based porous skeleton. Step S3, Phase Change Material Impregnation: The solid waste-based porous framework is dried and vacuumed. Molten phase change material is then impregnated into the solid waste-based porous framework and cooled to room temperature, so that the phase change material is solidified in the pores and stably loaded in the framework. Step S4, Surface encapsulation treatment: The encapsulation layer is wrapped around the solid waste-based porous skeleton obtained in step S3, and dried to obtain solid waste-based phase change aggregate.

7. The method for preparing solid waste-based phase change aggregate according to claim 6, characterized in that, The impregnation rate of phase change material in the porous framework based on solid waste is 82.6%~85.2%, and the leakage rate is 14.2%~15.1%.

8. The method for preparing solid waste-based phase change aggregate according to claim 6, characterized in that, The encapsulation layer contains solid waste raw materials and water, wherein the mass ratio of lithium slag, fly ash and yellow phosphorus slag is 20:50:30~30:50:20, and the water-ash ratio is 0.3~0.

4.

9. The method for preparing solid waste-based phase change aggregate according to claim 6, characterized in that, In step S3, a vacuum is drawn to -0.08 to -0.05 MPa and maintained for 2 to 3 hours. The molten phase change material is then immersed in the solid waste-based porous framework for 30 to 120 minutes.

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