Non-sintered ceramsite with polystyrene core and composite mineral shell and preparation method of non-sintered ceramsite

Abstract

According to the non-sintered ceramsite with the polystyrene core and the composite mineral shell and the preparation method of the non-sintered ceramsite, efficient bonding of the organic polystyrene core and the inorganic composite mineral shell is achieved through the innovative bonding accelerant; the bonding accelerator is formed by compounding a zirconate-acrylate complex, an epoxy-terminated polyether urethane prepolymer, methacryloyloxysilane and the like, and a'chemical crosslinking-physical anchoring-elastic buffering 'triple interface bonding mechanism is constructed through the dual action of'core pretreatment + addition during granulation', so that the interface bonding force and the structural toughness are improved. The problems of core-shell interface compatibility, forming stability and shell strength are solved, and the unfired ceramsite with high compressive strength, low water absorption and uniform and stable particles is prepared.

Description

Technical Field

[0001] This invention relates to the field of non-fired ceramsite technology, and in particular to a polystyrene core-composite mineral shell non-fired ceramsite and its preparation method. Background Technology

[0002] As the construction industry shifts towards "energy conservation, environmental protection, and lightweighting," lightweight aggregates, as core materials for reducing building weight and improving thermal insulation performance, are experiencing continuous market demand growth. Expanded clay aggregate (Cephalotaxus fortunei), a typical lightweight aggregate, is divided into two main categories: sintered Cephalotaxus fortunei and non-sintered Cephalotaxus fortunei. While sintered Cephalotaxus fortunei offers stable performance, it suffers from high energy consumption during high-temperature sintering, large carbon emissions, and potential for air pollution during production. In contrast, non-sintered Cephalotaxus fortunei, cured at room temperature without high-temperature sintering, offers advantages such as low energy consumption, low pollution, and controllable production costs, making it the main development direction for the Cephalotaxus fortunei industry.

[0003] In the research and development of non-fired ceramsite, the composite structure design of "organic core - inorganic shell" has attracted much attention. Polystyrene particles, due to their low density (0.02-0.05 g / cm³), are particularly noteworthy. 3 With low thermal conductivity (0.039-0.044 W / (m·K)), it is an ideal lightweight insulation core material, which can significantly reduce the overall density of ceramsite and improve insulation performance. The selection of the outer shell material focuses on the resource utilization of industrial solid waste. Stone tailings, a solid waste generated during stone processing, have an annual emission exceeding 500 million tons. Its main components are inorganic minerals such as silica and alumina, possessing certain filling properties and potential activity. Desulfurized gypsum, a byproduct of power plant flue gas desulfurization, has an annual production exceeding 200 million tons. Its main component is calcium sulfate dihydrate, exhibiting coagulation and hardening characteristics. Using these two bulk industrial solid wastes as the main raw materials for the composite mineral outer shell not only reduces the production cost of ceramsite but also reduces land occupation and environmental pollution problems caused by solid waste stockpiling, aligning with the concept of circular economy development.

[0004] However, this composite structure of non-fired ceramsite faces a key technical bottleneck—the interfacial bonding problem between the organic core and the inorganic shell. Polystyrene, as a non-polar organic polymer, has a smooth surface, strong hydrophobicity and inertness, and lacks active groups that can react with inorganic minerals. In contrast, inorganic minerals such as stone tailings and desulfurized gypsum are rich in hydroxyl groups, exhibiting strong hydrophilicity. The significant difference in interfacial properties between the two leads to extremely poor interfacial compatibility. Specifically, during the preparation process, the mineral shell slurry is difficult to uniformly coat the polystyrene particles, easily resulting in "shell detachment." During the use of the finished product, external forces, temperature changes, or humidity can cause micro-cracks at the core-shell interface, which can then develop into delamination and shell detachment. This directly leads to insufficient compressive strength and increased water absorption in the ceramsite, failing to meet the performance requirements of lightweight aggregates for construction.

[0005] To address the interfacial adhesion problem, existing technologies often employ the addition of coupling agents. However, conventional coupling agents are ill-suited for the complex composite system of polystyrene-stone tailings-desulfurized gypsum. The core mechanism of silane coupling agents involves the condensation reaction between the silanol groups generated by hydrolysis and the hydroxyl groups on the surface of inorganic minerals, forming chemical bonds. However, their organic functional groups have poor compatibility with polystyrene, failing to establish stable intermolecular forces at the organic-inorganic interface. While titanate coupling agents can combine with inorganic components through transesterification, and their long-chain alkyl groups can entangle with the organic phase, their compatibility with the calcium sulfate system in desulfurized gypsum is insufficient, hindering their effective coupling effect. Aluminate coupling agents primarily target inorganic fillers such as calcium carbonate and talc, offering limited enhancement of adhesion in the composite system of stone tailings and desulfurized gypsum. Therefore, developing a method for preparing non-fired ceramsite that can solve the core-shell interface bonding problem and take into account both shell strength and molding stability, and achieving efficient bonding between the organic core and inorganic shell through the design and optimized use of bonding accelerators, while improving the density and strength of the shell itself, is key to promoting the industrialization of polystyrene core-composite mineral shell non-fired ceramsite, and has significant economic and environmental value. Summary of the Invention

[0006] To address the problems of insufficient interfacial bonding, low shell strength, and poor molding uniformity in the preparation of existing polystyrene core-composite mineral shell non-fired ceramsite, this invention provides a polystyrene core-composite mineral shell non-fired ceramsite and its preparation method. By combining and dual-application of bonding accelerators and optimizing disc granulation parameters, the problems of core-shell interface compatibility, molding stability, and shell strength are solved simultaneously, resulting in non-fired ceramsite with high compressive strength, low water absorption, and uniform and stable particle size.

[0007] The technical solution adopted to achieve the above-mentioned objectives of this invention is as follows: 1. Core design concept: The key to this invention lies in the formulation design of the bonding accelerator, the dual use mode of the bonding accelerator of "core pretreatment + addition during granulation", and the process synergy of "synchronous control of powder and spray water addition" in the disc granulator.

[0008] The bonding accelerator breaks through the traditional coupling agent compound framework and adopts a multi-component synergistic system of "organometallic complex + reactive elastomer + catalytic active center". The zirconate-acrylate complex achieves two-way chemical binding between organic and inorganic components, the epoxy-terminated polyether urethane prepolymer buffers interfacial stress, and nano-hydroxyapatite activates the interfacial reaction, forming a triple action mechanism of "chemical crosslinking-physical anchoring-elastic buffering", which completely solves the interfacial compatibility problem between polystyrene and composite minerals. A uniform adsorption layer is formed on the surface of polystyrene through core pretreatment, and a bonding promoter is added simultaneously during granulation to provide dual protection for the bonding strength of the core-shell interface and the bonding stability between mineral particles. In the disc granulator, powder and sprayed water are added simultaneously and gradually. The rolling of the particles ensures that the powder is evenly coated, and the coating thickness is precisely controlled to improve the uniformity of the molding. The mineral powder and cement work together to activate the stone tailings and desulfurized gypsum, improving the density and strength of the hardened outer shell.

[0009] 2. Raw material selection and proportioning: Polystyrene granules: Select granules with a particle size of 3-6mm. If the particle size is too small, it will easily lead to an excessively thick outer shell and increased density. If the particle size is too large, it will affect the overall strength uniformity of the ceramsite. Composite mineral powder: by weight, it includes: 40-60 parts stone tailings powder, 20-30 parts desulfurized gypsum, 10-15 parts mineral powder (preferably S95 grade mineral powder, activity index ≥95%), and 5-10 parts cement (preferably P・O42.5 grade ordinary Portland cement). The mineral powder can activate the hydration activity of the desulfurized gypsum, and the cement provides early strength, synergistically improving the overall performance of the outer shell.

[0010] Bonding accelerator: By weight, it includes: 35-45 parts zirconate-acrylate complex, 15-25 parts epoxy-terminated polyether urethane prepolymer, 8-12 parts methacryloxysilane, 2-4 parts dibutyltin dilaurate, 3-6 parts polyether-modified polysiloxane, 20-28 parts composite solvent, and 1-3 parts nano-hydroxyapatite. Each component is specifically adapted to the "polystyrene-stone tailings-desulfurized gypsum" composite system—the zirconate-acrylate complex provides dual reaction sites, the epoxy-terminated polyether urethane prepolymer enhances interfacial toughness, methacryloxysilane strengthens compatibility, dibutyltin dilaurate catalyzes the crosslinking reaction, the polyether-modified polysiloxane ensures dispersion stability, nano-hydroxyapatite accelerates interfacial reactions, and the composite solvent improves the uniformity of dissolution of each component.

[0011] Dosage of bonding accelerator: The diluent for core pretreatment (bonding accelerator and solvent are mixed at a volume ratio of 1:(5-10), and the solvent can be the composite solvent in the bonding accelerator). The amount added during granulation is 1%-3% of the total mass of the composite mineral powder. If the amount is too low, the effective bonding effect cannot be achieved. If the amount is too high, the cost will increase and the water absorption rate of the ceramsite may increase. Water dosage: 20%-25% of the total mass of the composite mineral powder, added by spraying to ensure that the powder is evenly moistened and does not flow.

[0012] 3. Preparation method steps: Preparation of bonding accelerator: (1) Place the solvent of the formula amount in the reaction vessel, turn on the stirring device, and control the speed to 300-400 r / min; (2) Raise the temperature in the reaction vessel to 50-60℃, and add zirconate ester-acrylate complex and terminal epoxy polyether urethane prepolymer in sequence, and continue stirring for 60 min after each addition of a component; (3) Cool down to 30-40℃, add methacryloxysilane and nano hydroxyapatite, and stir for 45 min; (4) Add dibutyltin dilaurate and polyether modified polysiloxane, and continue stirring for 30 min. After stirring, cool to room temperature to obtain the bonding accelerator. The zirconate ester-acrylate complex is prepared by reacting tetrabutyl zirconate with hydroxyethyl acrylate; preferably, the zirconate ester-acrylate complex is prepared by mixing tetrabutyl zirconate and hydroxyethyl acrylate in a molar ratio of 1:2 and reacting at 70-80℃ for 2 h. The molecular weight of the terminal epoxy polyether urethane prepolymer is 2000-3000; the HLB value of the polyether-modified polysiloxane is 12-14; the particle size of the nano-hydroxyapatite is 50-100 nm; and the composite solvent is anhydrous ethanol and ethyl acetate mixed in a volume ratio of 7:3.

[0013] Polystyrene core pretreatment: Immerse polystyrene particles in a diluted bonding accelerator solution for 10-20 minutes to ensure that the bonding accelerator is fully adsorbed onto the particle surface to form an adsorption layer to improve surface adhesion. After removal, dry at 60-80℃ to constant weight to remove excess solvent from the surface and avoid affecting subsequent powder coating. The thickness of the pre-adsorbed bonding accelerator layer on the surface of the polystyrene particles is 0.01-0.05 mm.

[0014] Composite mineral powder mixing: Mix stone tailings, desulfurized gypsum, mineral powder and cement evenly according to the formula to obtain composite mineral powder for later use; Coating molding: Start the disc granulator and put the pretreated polystyrene granules into the equipment. After the granules form a stable rolling state with the rotation of the disc, add composite mineral powder and sprayed water gradually (powder addition rate 50-100g / min, water spray rate 12.5-35mL / min) and add bonding accelerator at the same time to make the powder uniformly coat the surface of the granules to form a shell, and control the coating layer thickness to 2-5mm. Room temperature and humidity curing: Take the formed granules out of the disc granulator and place them in a curing room at 20-25℃ and relative humidity ≥60% for 7-14 days.

[0015] The obtained non-fired ceramsite has an apparent density of 0.8-1.0 g / cm³, a compressive strength of ≥3 MPa, a water absorption rate of ≤10%, a thermal conductivity of ≤0.08 W / (m・K), a sphericity of ≥92%, and no shelling phenomenon after temperature change cycling from -20℃ to 60℃.

[0016] Compared with the prior art, the technical solution provided by the present invention has the following advantages: 1. Synergistic improvement of interface bonding and molding stability: The dual application of bonding promoter solves the core-shell interface bonding problem. Combined with optimized disc granulation parameters, the sphericity of ceramic particles is ≥90%, the coating layer thickness deviation is ≤±0.3mm, and there is no delamination or peeling.

[0017] 2. Excellent overall product performance: The apparent density of the obtained non-fired ceramsite is 0.8-1.0 g / cm³. 3 It has a compressive strength ≥3.0MPa, a water absorption rate ≤10%, and a thermal conductivity ≤0.08W / (m·K). It combines lightweight, high strength, low water absorption, and good thermal insulation performance, meeting the requirements of multiple application scenarios.

[0018] 3. High utilization rate of industrial solid waste: The total proportion of stone tailings and desulfurized gypsum in the composite mineral shell is over 70%, and a single ton of ceramsite can dispose of 0.6-0.8 tons of industrial solid waste, significantly reducing the pressure of solid waste disposal.

[0019] 4. Raw materials are readily available and low cost: The raw materials used are all common industrial materials, the bonding accelerator preparation process is simple, and the overall production cost is 10-15% lower than that of traditional non-fired ceramsite, making it highly competitive in the market. Detailed Implementation

[0020] The following embodiments describe in more detail the polystyrene core-composite mineral shell non-fired ceramsite and its preparation method of the present invention. These embodiments are given by way of illustration to enable those skilled in the art to understand and implement the invention, but these embodiments do not limit the scope of protection of the invention. All equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

[0021] In this embodiment of the invention, the compressive strength, water absorption rate and apparent density of the non-fired ceramsite were tested in accordance with GB / T17431.1-2010 "Lightweight aggregates and their test methods Part 2: Lightweight aggregate test methods", and the thermal conductivity was measured in accordance with GB / T10294-2008 "Determination of steady-state thermal resistance and related properties of thermal insulation materials - protective hot plate method". Example

[0022] The method for preparing polystyrene core-composite mineral shell non-fired ceramsite provided in this embodiment includes the following steps: Preparation of bonding accelerator: 25 parts by weight of anhydrous ethanol-ethyl acetate composite solvent (volume ratio 7:3) were placed in a reaction vessel, stirred at 350 r / min, and heated to 55℃. 40 parts of zirconate-acrylate complex and 20 parts of terminal epoxy-terminated polyether urethane prepolymer (molecular weight 2500) were added sequentially, stirring for 60 min after each addition. The temperature was lowered to 35℃, and 10 parts of methacryloxysilane and 2 parts of nano-hydroxyapatite (particle size 80 nm) were added, stirring for 45 min. Finally, 3 parts of dibutyltin dilaurate and 4 parts of polyether-modified polysiloxane (HLB value 13) were added, stirring for 30 min, and cooled to room temperature to obtain the bonding accelerator. The zirconate-acrylate complex was prepared by mixing tetrabutyl zirconate and hydroxyethyl acrylate in a molar ratio of 1:2 and reacting at 70-80℃ for 2 h.

[0023] Preparation of non-fired ceramsite: Core pretreatment: Take polystyrene particles with a particle size of 5-6 mm, immerse them in a bonding accelerator-composite solvent dilution solution (volume ratio 1:8) for 15 min, and dry them at 70℃ to constant weight, thereby pre-adsorbing a bonding accelerator adsorption layer with a thickness of 0.01-0.05 mm on the surface of the polystyrene particles.

[0024] Composite mineral powder mixing: Take 50 parts by weight of stone tailings powder, 25 parts of desulfurized gypsum, 12 parts of S95 grade mineral powder, and 8 parts of P·O42.5 grade cement, mix them evenly to obtain composite mineral powder; Coating molding: Start the disc granulator, put the pretreated polystyrene granules into the equipment, and after the granules roll steadily, add composite mineral powder at a rate of 70g / min, and simultaneously add spray water at a rate of 21mL / min (the amount of water is 25% of the total mass of the powder), and simultaneously add 2% (relative to the total amount of powder) of bonding accelerator, and control the coating layer thickness to 3mm. [Assuming 70g of powder is added at a rate of 70g / min, it takes 1 minute to complete. At this point, 17.50g of water needs to be added. Adding this at a rate of 21mL / min would take 0.83 minutes. This means that if the powder is added at the above rate, the water will be added before the powder is completely added. This problem also exists in later examples. It is recommended to control only the addition rate of one item.] Curing: Place in a curing room at 23℃ and 85% relative humidity for 10 days to obtain non-fired ceramsite.

[0025] The apparent density of the ceramsite was measured to be 0.9 g / cm³. 3 The compressive strength of the cylinder is 3.2 MPa, the water absorption rate is 8.5%, the thermal conductivity is 0.075 W / (m・K), the sphericity of the particles is 92%, and the core and shell are firmly bonded after temperature change cycling from -20℃ to 60℃ without any detachment. Example

[0026] The method for preparing polystyrene core-composite mineral shell non-fired ceramsite provided in this embodiment includes the following steps: Preparation of bonding accelerator: 28 parts by weight of anhydrous ethanol-ethyl acetate composite solvent (volume ratio 7:3) were placed in a reaction vessel, stirred at 380 r / min, and heated to 58℃; 35 parts of zirconate-acrylate complex and 25 parts of terminal epoxy polyether urethane prepolymer (molecular weight 3000) were added sequentially, and stirred for 60 min at each step; the temperature was lowered to 38℃, 12 parts of methacryloxysilane and 3 parts of nano hydroxyapatite (particle size 100 nm) were added, and stirred for 45 min; finally, 4 parts of dibutyltin dilaurate and 6 parts of polyether modified polysiloxane (HLB value 14) were added, stirred for 30 min, and cooled to room temperature to obtain the bonding accelerator.

[0027] Preparation of non-fired ceramsite: Core pretreatment: Take polystyrene particles with a particle size of 4-5 mm, immerse them in a bonding accelerator-composite solvent dilution solution (volume ratio 1:7) for 18 min, and dry them at 75℃ to constant weight, thereby pre-adsorbing a bonding accelerator adsorption layer with a thickness of 0.01-0.05 mm on the surface of the polystyrene particles. Composite mineral powder mixing: Take 55 parts by weight of stone tailings powder, 20 parts of desulfurized gypsum, 10 parts of S95 grade mineral powder, and 10 parts of P·O42.5 grade cement, mix them evenly to obtain composite mineral powder; Coating molding: Start the disc granulator, put the pretreated polystyrene granules into the equipment, and after the granules roll steadily, add composite mineral powder at a rate of 80 g / min, and simultaneously spray water at a rate of 25.6 mL / min (the amount of water is 23% of the total mass of the powder), and add 2.5% bonding accelerator, and control the coating layer thickness to 4 mm. Curing: Place in a curing room at 24℃ and 88% relative humidity for 12 days to obtain non-fired ceramsite.

[0028] The apparent density of the ceramsite was measured to be 0.95 g / cm³. 3 The core and shell have a compressive strength of 3.6 MPa, a water absorption rate of 7.2%, a thermal conductivity of 0.080 W / (m・K), and a particle sphericity of 93%. After temperature cycling from -20℃ to 60℃, the core and shell are firmly bonded together without any detachment. Example

[0029] Preparation of bonding accelerator: Take 20 parts by weight of anhydrous ethanol-ethyl acetate composite solvent (volume ratio 7:3) and place it in a reaction vessel. Stir at 320 r / min and heat to 52℃. Add 45 parts of zirconate-acrylate complex and 15 parts of epoxy-terminated polyether urethane prepolymer (molecular weight 2000) in sequence, stirring for 60 min each time. Cool down to 32℃, add 8 parts of methacryloxysilane and 1 part of nano-hydroxyapatite (particle size 50 nm), and stir for 45 min. Finally, add 2 parts of dibutyltin dilaurate and 3 parts of polyether modified polysiloxane (HLB value 12), stir for 30 min, and cool to room temperature to obtain the bonding accelerator.

[0030] Preparation of non-fired ceramsite: Core pretreatment: Take polystyrene particles with a particle size of 3-6 mm, immerse them in a bonding accelerator-composite solvent dilution solution (volume ratio 1:10) for 12 min, and dry them at 65℃ to constant weight, thereby pre-adsorbing a bonding accelerator adsorption layer with a thickness of 0.01-0.05 mm on the surface of the polystyrene particles. Composite mineral powder mixing: Take 45 parts by weight of stone tailings powder, 30 parts of desulfurized gypsum, 15 parts of S95 grade mineral powder, and 5 parts of P·O42.5 grade cement, mix them evenly to obtain composite mineral powder; Coating molding: Start the disc granulator, put the pretreated polystyrene granules into the equipment, and after the granules roll steadily, add composite mineral powder at a rate of 60 g / min, and simultaneously spray water at a rate of 16.8 mL / min (the amount of water is 21% of the total mass of the powder), and add 1.5% bonding accelerator, and control the coating layer thickness to 2 mm. Curing: Place in a curing room at 22℃ and 82% relative humidity for 9 days to obtain non-fired ceramsite.

[0031] The apparent density of the expanded clay aggregate was measured to be 0.85 g / cm³. 3 The compressive strength of the cylinder is 3.0 MPa, the water absorption rate is 9%, the thermal conductivity is 0.070 W / (m・K), the sphericity of the particles is 91%, and the core and shell are firmly bonded after temperature change cycling from -20℃ to 60℃ without any detachment.

[0032] Comparative Example 1 In this comparative example, the polystyrene particles were not pretreated with a diluted bonding accelerator, and no bonding accelerator was added during granulation. The remaining preparation steps were the same as in Example 1. The apparent density of the ceramsite was measured to be 0.92 g / cm³. 3 The compressive strength of the cylinder is 1.8 MPa, the water absorption rate is 15.2%, the sphericity of the particles is 80%, and 30% of the particles show shell detachment after curing, indicating severe inadequate interfacial adhesion.

[0033] Comparative Example 2 In this comparative example, during granulation, all the composite mineral powder and bonding accelerator were added first, followed by spraying water. The remaining preparation steps were the same as in Example 1. Testing revealed that the thickness deviation of the ceramsite coating was ±0.8 mm, the sphericity of the particles was 78%, some particles experienced shell cracking due to localized water accumulation, the cylinder compressive strength was 2.4 MPa, and the water absorption rate was 10.6%.

[0034] Comparative Example 3 A single aminosilane coupling agent was used to replace the bonding accelerator of this invention, and the preparation steps and addition amount were the same as in Example 1. Testing showed that the ceramsite had a compressive strength of 2.3 MPa, a water absorption rate of 11.5%, a particle sphericity of 85%, and some particles exhibited core-shell delamination.

[0035] This invention achieves efficient bonding between an organic polystyrene core and an inorganic composite mineral shell through an innovative bonding accelerator. The composite mineral shell is mainly made from stone tailings and desulfurized gypsum, supplemented with mineral powder and cement. The bonding accelerator is a compound of zirconate-acrylate complex, epoxy-terminated polyether urethane prepolymer, and methacryloxysilane, etc. Through the dual action of "core pretreatment + addition during granulation", a triple interface bonding mechanism of "chemical crosslinking - physical anchoring - elastic buffering" is constructed, improving the interfacial bonding force and structural toughness. The preparation process includes polystyrene core pretreatment, composite mineral shell powder preparation, disc granulation and coating, and room temperature curing, without the need for high-temperature sintering. The resulting non-fired ceramsite has a compressive strength ≥3MPa, a water absorption rate ≤10%, uniform and stable particles, excellent lightweight thermal insulation performance, and can largely dispose of industrial solid waste. It has low energy consumption and good environmental performance, and is suitable for building insulation, lightweight aggregates and other fields.

Claims

1. A type of non-fired ceramsite with a polystyrene core and a composite mineral shell, characterized in that: The non-fired ceramsite has a core-shell structure. The core is polystyrene particles, and the surface of the polystyrene particles is pre-adsorbed with a bonding accelerator adsorption layer. The outer shell is made of composite mineral powder with stone tailings and desulfurized gypsum as the main raw materials. A bonding accelerator is added simultaneously with the composite mineral powder during granulation. The amount of bonding accelerator added is 1%-3% of the total mass of the composite mineral powder. The bonding accelerator comprises, by weight, 35-45 parts of zirconate-acrylate complex, 15-25 parts of epoxy-terminated polyether urethane prepolymer, 8-12 parts of methacryloxysilane, 2-4 parts of dibutyltin dilaurate, 3-6 parts of polyether-modified polysiloxane, 20-28 parts of composite solvent, and 1-3 parts of nano-hydroxyapatite.

2. The polystyrene core-composite mineral shell non-fired ceramsite according to claim 1, characterized in that: The thickness of the bonding accelerator adsorption layer pre-adsorbed on the surface of the polystyrene particles is 0.01-0.05 mm.

3. The polystyrene core-composite mineral shell non-fired ceramsite according to claim 1, characterized in that: Polystyrene particles are immersed in a diluted solution of bonding accelerator for a period of time, then removed and dried to constant weight to obtain polystyrene particles with a bonding accelerator adsorption layer on the surface.

4. The polystyrene core-composite mineral shell non-fired ceramsite according to claim 3, characterized in that: The diluted solution of the bonding accelerator is prepared by mixing the bonding accelerator and the solvent at a volume ratio of 1:(5-10).

5. The polystyrene core-composite mineral shell non-fired ceramsite according to claim 1, characterized in that: The composite mineral powder comprises, by weight, 40-60 parts stone tailings powder, 20-30 parts desulfurized gypsum, 10-15 parts mineral powder, and 5-10 parts cement.

6. The polystyrene core-composite mineral shell non-fired ceramsite according to claim 1, characterized in that: The bonding accelerator is prepared as follows: a composite solvent is added to a reaction vessel, stirring is started and the temperature is raised to 50-60°C, zirconate ester-acrylate complex and epoxy-terminated polyether urethane prepolymer are added sequentially, and stirring is continued for a period of time after each component is added; the temperature is lowered to 30-40°C, methacryloxysilane and nano-hydroxyapatite are added, and stirring is continued for a period of time; dibutyltin dilaurate and polyether-modified polysiloxane are added, and stirring is continued for a period of time. After stirring is completed, the mixture is cooled to room temperature to obtain the bonding accelerator.

7. The polystyrene core-composite mineral shell non-fired ceramsite according to claim 1, characterized in that: The zirconate-acrylate complex is prepared by reacting tetrabutyl zirconate with hydroxyethyl acrylate; the molecular weight of the terminal epoxy polyether urethane prepolymer is 2000-3000; the HLB value of the polyether-modified polysiloxane is 12-14; the particle size of the nano-hydroxyapatite is 50-100 nm; and the composite solvent is anhydrous ethanol and ethyl acetate mixed in a volume ratio of 7:

3.

8. A method for preparing polystyrene core-composite mineral shell non-fired ceramsite according to any one of claims 1-7, characterized in that... Includes the following steps: (1) Weigh the stone tailings according to the weight parts and mix them evenly to obtain composite mineral powder; (2) The polystyrene particles pre-adsorbed with a bonding accelerator adsorption layer are put into the disc granulator. After the equipment is turned on, composite mineral powder, sprayed water and bonding accelerator are added to the equipment at the same time to make the powder uniformly coated on the surface of the particles to obtain core-shell structured granules. (3) After the shaped particles are cured, polystyrene core-composite mineral shell non-fired ceramic particles are obtained.

9. The method for preparing polystyrene core-composite mineral shell non-fired ceramsite according to claim 8, characterized in that: The polystyrene particles have a particle size of 3-6 mm; the coating layer thickness is 2-5 mm.

10. The method for preparing polystyrene core-composite mineral shell non-fired ceramsite according to claim 8, characterized in that: In step (2), the amount of water added is 20%-25% of the total mass of the composite mineral powder; In step (2), the addition rate of the composite mineral powder is 50-100 g / min, and the water spray rate is 12.5-35 mL / min; The curing conditions for the formed particles in step (3) are: curing in an environment with a temperature of 20-25℃ and a relative humidity of ≥60% for 7-14 days.