A method for resource utilization of phosphogypsum as thermal insulation material

Abstract

The present invention discloses a method for producing a thermal insulation material for resource utilization of phosphogypsum, and relates to the technical field of non-metallic materials. The method comprises screening phosphogypsum raw materials to remove impurities; subjecting the screened phosphogypsum raw materials to heat treatment to remove moisture and obtain phosphogypsum particles with uniform particle size; the temperature range of the heat treatment is 300°C to 500°C, and the treatment time is 1 to 3 hours. The present invention adopts a sol-gel method to stably fix antibacterial and mildew-proof components on the surface of phosphogypsum particles, so that the modified phosphogypsum maintains excellent thermal insulation performance. The thermal insulation effect of the material is further enhanced by surface modification and a reasonable ratio of composite materials. The material also has good environmental adaptability and is particularly suitable for use in humid, warm and other environments prone to mold growth, so that it can work stably for a long time in a variety of environments.

Description

Technical Field

[0001] The invention relates to the technical field of non-metallic materials, in particular to a method for resource utilization of phosphogypsum as a heat-insulating material. Background Art

[0002] Phosphogypsum is a by-product produced during the production of phosphate fertilizers. Its main component is calcium sulfate dihydrate, which also contains small amounts of phosphorus, magnesium, aluminum and other elements. With the continuous expansion of the scale of phosphate fertilizer production and phosphoric acid production, the accumulation of phosphogypsum has increased year by year, becoming an industrial waste that urgently needs to be treated. According to relevant statistics, the world's annual production of phosphogypsum is about 250 million tons, most of which is piled up or treated, resulting in increasingly serious waste of resources and environmental pollution. With the increasingly stringent environmental regulations, the resource utilization of phosphogypsum has gradually become an important issue for the development of the industry. In recent years, researchers have proposed a variety of methods for the resource utilization of phosphogypsum, mainly focusing on the fields of building materials, soil improvement, environmental remediation, etc. For example, phosphogypsum is widely used in the production of gypsum board, compound fertilizers, cement and soil conditioners.

[0003] Beyond traditional applications, a growing number of researchers are focusing on the high-value utilization of phosphogypsum, with its use as a thermal insulation material emerging as a new development. Studies have shown that, through appropriate modification, phosphogypsum can exhibit improved properties such as low thermal conductivity, flame retardancy, and pressure resistance. Therefore, using phosphogypsum to prepare thermal insulation materials can not only effectively alleviate the environmental pressures caused by phosphogypsum accumulation, but also provide an environmentally friendly and highly effective thermal insulation material for the construction industry.

[0004] However, in the prior art, the application of phosphogypsum in thermal insulation materials still faces some challenges, especially in terms of the material's stability, moisture resistance, and antibacterial and mildew-proof properties. Although some phosphogypsum thermal insulation materials have improved the thermal conductivity and compressive strength of the material by compounding with thermal insulation materials such as expanded perlite and polymers, these composite materials generally lack adaptability to humid environments. In humid or high-temperature environments, phosphogypsum materials easily absorb moisture and expand, causing their structure to be damaged and losing their thermal insulation function. In addition, phosphogypsum may also breed bacteria and mold during long-term use, which poses a potential threat to the material's service life and environmental hygiene. Therefore, how to introduce antibacterial, mildew-proof and other functions into phosphogypsum thermal insulation materials to improve their application effect in humid environments has become a technical problem that needs to be solved urgently. Summary of the Invention

[0005] In view of the problems existing in the above background technology, the present invention is proposed.

[0006] Therefore, the problem to be solved by the present invention is how to solve the problem of insufficient stability and durability of phosphogypsum insulation materials in humid environments in the prior art.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0008] In a first aspect, an embodiment of the present invention provides a method for producing a thermal insulation material by resource utilization of phosphogypsum, comprising: screening phosphogypsum raw materials to remove impurities; subjecting the screened phosphogypsum raw materials to heat treatment to remove moisture and obtain phosphogypsum particles of uniform particle size; the heat treatment temperature range is 300°C to 500°C, and the treatment time is 1 to 3 hours; and dynamic temperature control technology is introduced during the heat treatment process to adjust the temperature according to the moisture content monitored in real time.

[0009] As a preferred embodiment of the method for resource utilization of phosphogypsum as an insulating material according to the present invention, the heat treatment temperature is 350°C to 450°C, the treatment time is 1.5 hours to 2.5 hours, and the moisture content of the phosphogypsum particles is reduced to below 3%; the dynamic temperature control technology includes a feedback adjustment mechanism based on real-time moisture content to achieve optimal matching of treatment temperature and time.

[0010] As a preferred embodiment of the method for resource utilization of phosphogypsum as an insulating material according to the present invention, it further comprises: performing antibacterial and mildew-proof surface modification on the phosphogypsum particles, combining the antibacterial and mildew-proof components with the surface of the phosphogypsum particles; the antibacterial and mildew-proof components are metal compounds of silver, copper or zinc; the mass ratio of the antibacterial and mildew-proof components is 0.1% to 5% of the phosphogypsum particles.

[0011] As a preferred embodiment of the method for resource utilization of phosphogypsum as an insulating material according to the present invention, the antibacterial and mildew-proof surface modification treatment adopts a sol-gel method, in which silver ion, zinc ion or copper ion compound is dissolved in a solution with a pH of 5 to 7, and an interfacial reaction occurs with the phosphogypsum particles to form a stable antibacterial layer; the surface coverage of the antibacterial and mildew-proof component is 70% to 95%.

[0012] As a preferred solution of the method for resource utilization of phosphogypsum as an insulating material according to the present invention, the mass ratio of the antibacterial and mildew-proof component is 0.5% to 3% of the phosphogypsum particles, and the antibacterial properties of the material are optimized by controlling the metal ion concentration.

[0013] As a preferred embodiment of the method for resource utilization of phosphogypsum as an insulating material according to the present invention, it further comprises: mixing surface-modified phosphogypsum particles with other insulating materials to obtain a composite material; the insulating material comprises expanded perlite, polymer-based materials or low thermal conductivity mineral particles, and the mass ratio of the phosphogypsum particles to the expanded perlite is 3:1 to 7:1.

[0014] As a preferred embodiment of the method for resource utilization of phosphogypsum as an insulating material according to the present invention, the mixing ratio of the composite material is 40% to 70% by mass of phosphogypsum particles, expanded perlite and polymer-based material: 10% to 30% by mass: 10% to 20% by mass; the composite material is formed by a mold to obtain an insulating material board or block in the desired shape; the mold forming process includes press molding or injection molding, the pressure is 5 MPa to 20 MPa, and the molding temperature is 40°C to 80°C.

[0015] As a preferred embodiment of the method for resource utilization of phosphogypsum as an insulating material according to the present invention, the composite material after mold forming is dried and cured; the drying temperature is 40°C to 70°C, and the curing time is 4 to 12 hours; the curing process is carried out in an environment with a relative humidity of 40% to 60%, and the density of the obtained composite material is 0.3g / cm³ to 1.5g / cm³.

[0016] As a preferred solution of the method for resource utilization of phosphogypsum as an insulating material of the present invention, the polymer-based material is polyurethane or polystyrene, and a blending method is used to ensure uniform dispersion and form a stable microstructure.

[0017] As a preferred solution of the method for resource utilization of phosphogypsum as an insulating material according to the present invention, the dynamic temperature control technology in the heat treatment process realizes precise temperature control by monitoring the real-time moisture content, and dynamically adjusts the temperature range of the heat treatment through feedback.

[0018] The beneficial effects of the present invention are as follows: the present invention performs antibacterial and mildew-proof modification on the surface of phosphogypsum particles, uses metal compounds such as silver, copper or zinc as antibacterial and mildew-proof components, and combines them with the surface of phosphogypsum particles, thereby significantly improving the antibacterial and mildew-proof properties of the material.

[0019] At the same time, the present invention uses a sol-gel method to stably fix the antibacterial and mildew-proof components on the surface of phosphogypsum particles, allowing the modified phosphogypsum to maintain excellent thermal insulation properties. The thermal insulation effect of this material is further enhanced through surface modification and the rational proportioning of the composite material. It also has good environmental adaptability and is particularly suitable for use in humid, warm and other environments prone to mold growth, enabling it to operate stably for long periods of time in a variety of environments. The present invention effectively solves the problem of insufficient stability and durability of phosphogypsum insulation materials in humid environments in the prior art, and improves its wide application and long-term use effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 Flow chart of a method for resource utilization of phosphogypsum as an insulation material. DETAILED DESCRIPTION

[0022] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, the following detailed description of the specific embodiments of the present invention is given in conjunction with the accompanying drawings. It is obvious that the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in this field without creative work should fall within the scope of protection of the present invention.

[0023] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0024] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0025] The present invention is described in detail with reference to schematic diagrams. For ease of illustration, cross-sectional views of device structures may be partially enlarged and not to scale when describing embodiments of the present invention. Furthermore, the schematic diagrams are merely illustrative and should not limit the scope of the present invention. Furthermore, in actual production, the three-dimensional dimensions of length, width, and depth should be included.

[0026] In the description of the present invention, it should be noted that the terms "upper, lower, inner, and outer" and other references to orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first, second, or third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] In this disclosure, unless otherwise specified or limited, the terms "mounted," "connected," and "connected" should be interpreted broadly. For example, they may refer to fixed, removable, or integral connections. They may also refer to mechanical, electrical, or direct connections, indirect connections through an intermediary, or internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in this disclosure.

[0028] Example 1

[0029] Reference Figure 1 This is the first embodiment of the present invention, which provides an experiment on the thermal insulation performance of phosphogypsum particles. The materials used include screened phosphogypsum raw materials, expanded perlite, a mold, a pressing machine, a heat flow meter, and an oven. The specific operations are as follows:

[0030] Select phosphogypsum raw materials with smaller particles and less impurities, and screen them through a sieve to remove impurities with particle sizes less than 0.5 mm and larger than 5 mm. The raw material particles after screening range from 0.5 mm to 5 mm.

[0031] The screened phosphogypsum particles are placed in a heat treatment furnace.

[0032] Dynamic temperature control technology is introduced during the heat treatment process to monitor the moisture content of the phosphogypsum particles in real time and automatically adjust the temperature based on moisture changes. The initial temperature setting is 350°C, with a dynamic adjustment range of 350°C to 400°C. The treatment time is 1.5 hours, ensuring that the moisture content is reduced to below 3%.

[0033] Specifically, the initial heat treatment temperature is set at 350°C, a relatively conservative temperature that effectively initiates the dehydration process of the phosphogypsum particles while preventing excessive temperatures from causing particle cracking. During this initial stage, the temperature control system maintains a low temperature to slow the evaporation rate and prevent excessive evaporation from causing the outer layer of the particles to dehydrate and crack.

[0034] As the moisture content gradually decreases, the temperature control system automatically adjusts the temperature based on the moisture data. When the moisture content decreases to a certain level, the furnace temperature is gradually increased (for example, to 400°C) to accelerate the evaporation of the remaining moisture.

[0035] It should be noted that high temperatures and rapid water evaporation can cause an overly hard shell to form on the surface of phosphogypsum particles, leading to cracking. Dynamic temperature control technology detects when the water is about to be completely removed and reduces the temperature appropriately, preventing thermal expansion and cracking of the particles caused by large temperature differences.

[0036] To ensure simultaneous removal of moisture from both the surface and interior of the phosphogypsum particles, a progressive temperature control strategy is employed. For example, the initial temperature is 350°C to ensure gentle dehydration, while the temperature is later increased to 400°C to accelerate dehydration, ultimately ensuring that the surface moisture of the particles is less than 3%.

[0037] Dynamic adjustment of temperature helps to improve dehydration efficiency and prevent cracking of phosphogypsum particles. Dynamic temperature control ensures efficient use of energy, avoids energy waste at excessively high temperatures, and reduces the total energy consumption of the heat treatment process.

[0038] Mix the heat-treated phosphogypsum particles with expanded perlite in a mass ratio of 4:1. Use a mixer to mix the two materials evenly.

[0039] The mixed composite material was placed in a mold and formed using a press molding machine at a temperature of 60°C, a pressure set to 10 MPa, and a molding time of 10 minutes to produce an insulation board with a thickness of 10 mm.

[0040] The formed material was dried in an oven at 70°C for 12 hours and cured for 4 hours.

[0041] The thermal conductivity of the material was tested using a heat flow meter method. The test environment temperature was set at 25°C and the humidity was 50%. Multiple measurements were performed at 25°C, 35°C, and 45°C. Each step was strictly carried out in accordance with the steps in the invention. To ensure the accuracy of the data, multiple groups of experiments were conducted, and the processing results and relevant data of each group of experiments were recorded, as shown in Table 1.

[0042] Table 1 Thermal conductivity test results of thermal insulation materials

[0043]

[0044] As shown in Table 1, the thermal conductivity of the composite material decreases with increasing phosphogypsum particle content. In particular, when the phosphogypsum particle content reaches 70%, the thermal conductivity drops to 0.025 W / m·K, demonstrating excellent thermal insulation performance. The introduction of dynamic temperature control technology improves the stability and efficiency of the heat treatment process, allowing for more uniform dehydration of the phosphogypsum particles during treatment, further enhancing thermal insulation performance.

[0045] Stability tests also show that the composite material can still maintain good thermal stability under changes in temperature and humidity, with the stability maintained at above 92%. This result shows that the thermal insulation material of the present invention has good thermal isolation performance and can effectively cope with temperature changes in different environments.

[0046] Example 2

[0047] The second embodiment of the present invention provides an antibacterial and mildew-proofing performance experiment of phosphogypsum particles to verify the antibacterial and mildew-proofing performance of the phosphogypsum particle composite material. The specific steps are as follows:

[0048] Select phosphogypsum raw materials with smaller particles and less impurities, and screen them through a sieve to remove impurities with particle sizes less than 0.5 mm and larger than 5 mm. The raw material particles after screening range from 0.5 mm to 5 mm.

[0049] The screened phosphogypsum particles are placed in a heat treatment furnace.

[0050] Dynamic temperature control technology is introduced during the heat treatment process to monitor the moisture content of the phosphogypsum particles in real time and automatically adjust the temperature based on moisture changes. The initial temperature setting is 350°C, with a dynamic adjustment range of 350°C to 400°C. The treatment time is 1.5 hours, ensuring that the moisture content is reduced to below 3%.

[0051] Specifically, the initial heat treatment temperature is set at 350°C, a relatively conservative temperature that effectively initiates the dehydration process of the phosphogypsum particles while preventing excessive temperatures from causing particle cracking. During this initial stage, the temperature control system maintains a low temperature to slow the evaporation rate and prevent excessive evaporation from causing the outer layer of the particles to dehydrate and crack.

[0052] As the moisture content gradually decreases, the temperature control system automatically adjusts the temperature based on the moisture data. When the moisture content decreases to a certain level, the furnace temperature is gradually increased (for example, to 400°C) to accelerate the evaporation of the remaining moisture.

[0053] It should be noted that high temperatures and rapid water evaporation can cause an overly hard shell to form on the surface of phosphogypsum particles, leading to cracking. Dynamic temperature control technology detects when the water is about to be completely removed and reduces the temperature appropriately, preventing thermal expansion and cracking of the particles caused by large temperature differences.

[0054] To ensure simultaneous removal of moisture from both the surface and interior of the phosphogypsum particles, a progressive temperature control strategy is employed. For example, the initial temperature is 350°C to ensure gentle dehydration, while the temperature is later increased to 400°C to accelerate dehydration, ultimately ensuring that the surface moisture of the particles is less than 3%.

[0055] Dynamic adjustment of temperature helps to improve dehydration efficiency and prevent cracking of phosphogypsum particles. Dynamic temperature control ensures efficient use of energy, avoids energy waste at excessively high temperatures, and reduces the total energy consumption of the heat treatment process.

[0056] Dissolve a silver ion compound (e.g., silver nitrate AgNO3) in an aqueous solution with a pH of 6.0, with the concentration controlled at 0.5 M. Add an appropriate amount of alcohol solvent and gelling agent to ensure that the silver ions are stably suspended in the solution.

[0057] Add heat-treated phosphogypsum particles (particle size ranges from 0.5 mm to 5 mm) into the antibacterial solution and stir evenly so that their surfaces can fully contact the solution.

[0058] Through the sol-gel method, silver ions react with the surface of phosphogypsum particles to form a stable antibacterial layer.

[0059] The reaction is carried out at room temperature for 30 minutes to 1 hour to ensure that the silver ions are evenly deposited on the surface of the particles.

[0060] The surface coverage of the antibacterial modified phosphogypsum particles reaches 85%, and the mass ratio of the antibacterial and mildew-proof components is 2% of the phosphogypsum particles.

[0061] The antibacterial modified phosphogypsum particles were dried at 60 °C for 2 h to remove excess solvent from the surface and stabilize the antibacterial layer.

[0062] The antibacterial modified phosphogypsum particles and expanded perlite were mixed in a mass ratio of 3:1 to obtain a composite material.

[0063] Escherichia coli and Candida albicans were selected as test bacteria, and the antibacterial inhibition rate was determined using the inhibition ring method. Each group of experiments was measured three times, as follows:

[0064] Table 2 Antibacterial and mildew-proof performance test results

[0065]

[0066] The data in Table 2 show that the antibacterial properties of phosphogypsum particles improve significantly with increasing silver ion content. At a silver ion content of 1.0%, the antibacterial effect is very significant, with inhibition rates of Escherichia coli and Candida albicans reaching 85% and 90%, respectively. This demonstrates that the present invention significantly enhances the antibacterial and mildew-proofing capabilities of the material through surface modification, offering significant antibacterial advantages over conventional materials.

[0067] Example 3

[0068] The third embodiment of the present invention provides an environmental adaptability test for composite materials to verify the stability and adaptability of composite materials under different environmental conditions. The specific steps are as follows:

[0069] Select phosphogypsum raw materials with smaller particles and less impurities, and screen them through a sieve to remove impurities with particle sizes less than 0.5 mm and larger than 5 mm. The raw material particles after screening range from 0.5 mm to 5 mm.

[0070] Dynamic temperature control technology is introduced during the heat treatment process to monitor the moisture content of the phosphogypsum particles in real time and automatically adjust the temperature based on moisture changes. The initial temperature setting is 350°C, with a dynamic adjustment range of 350°C to 400°C. The treatment time is 1.5 hours, ensuring that the moisture content is reduced to below 3%.

[0071] Specifically, the initial heat treatment temperature is set at 350°C, a relatively conservative temperature that effectively initiates the dehydration process of the phosphogypsum particles while preventing excessive temperatures from causing particle cracking. During this initial stage, the temperature control system maintains a low temperature to slow the evaporation rate and prevent excessive evaporation from causing the outer layer of the particles to dehydrate and crack.

[0072] As the moisture content gradually decreases, the temperature control system automatically adjusts the temperature based on the moisture data. When the moisture content decreases to a certain level, the furnace temperature is gradually increased (for example, to 400°C) to accelerate the evaporation of the remaining moisture.

[0073] It should be noted that high temperatures and rapid water evaporation can cause an overly hard shell to form on the surface of phosphogypsum particles, leading to cracking. Dynamic temperature control technology detects when the water is about to be completely removed and reduces the temperature appropriately, preventing thermal expansion and cracking of the particles caused by large temperature differences.

[0074] To ensure simultaneous removal of moisture from both the surface and interior of the phosphogypsum particles, a progressive temperature control strategy is employed. For example, the initial temperature is 350°C to ensure gentle dehydration, while the temperature is later increased to 400°C to accelerate dehydration, ultimately ensuring that the surface moisture of the particles is less than 3%.

[0075] Dynamic adjustment of temperature helps to improve dehydration efficiency and prevent cracking of phosphogypsum particles. Dynamic temperature control ensures efficient use of energy, avoids energy waste at excessively high temperatures, and reduces the total energy consumption of the heat treatment process.

[0076] Dissolve a silver ion compound (e.g., silver nitrate AgNO3) in an aqueous solution with a pH of 6.0, with the concentration controlled at 0.5 M. Add an appropriate amount of alcohol solvent and gelling agent to ensure that the silver ions are stably suspended in the solution.

[0077] Add heat-treated phosphogypsum particles (particle size ranges from 0.5 mm to 5 mm) into the antibacterial solution and stir evenly so that their surfaces can fully contact the solution.

[0078] Through the sol-gel method, silver ions react with the surface of phosphogypsum particles to form a stable antibacterial layer.

[0079] The reaction is carried out at room temperature for 30 minutes to 1 hour to ensure that the silver ions are evenly deposited on the surface of the particles.

[0080] The surface coverage of the antibacterial modified phosphogypsum particles reaches 85%, and the mass ratio of the antibacterial and mildew-proof components is 2% of the phosphogypsum particles.

[0081] The antibacterial modified phosphogypsum particles were dried at 60 °C for 2 h to remove excess solvent from the surface and stabilize the antibacterial layer.

[0082] Take antibacterial modified phosphogypsum particles, expanded perlite and polyurethane (or polystyrene) based materials and mix them according to the mass ratio. The mass ratio of phosphogypsum particles to expanded perlite is 4:1, and the mass ratio of phosphogypsum particles to polymer based materials is 6:1.

[0083] The mixed material was placed in a mold and pressurized by a press molding machine at a pressure of 15 MPa for 10 minutes, and then dried in an oven at a temperature set to 70°C for 12 hours.

[0084] The composite materials were exposed to high temperature and high humidity (50°C, 80% RH) and low temperature and low humidity (-5°C, 30% RH) environments for 30 days. Compressive strength and thermal conductivity tests were performed weekly. Partial treatment results and related data for each set of experiments were recorded, as shown in Table 3.

[0085] Table 3 Environmental adaptability test results

[0086]

[0087] The data in Table 3 demonstrates that the composite material exhibits minimal changes in compressive strength and thermal conductivity under varying conditions, demonstrating excellent environmental adaptability. In particular, under high-temperature and high-humidity conditions, the composite material exhibits only a slight decrease in thermal conductivity and compressive strength, demonstrating its strong stability. This demonstrates that the composite material of the present invention can adapt to various harsh environments while maintaining its highly effective thermal insulation performance.

[0088] In summary, it can be seen that the present invention adopts the sol-gel method to stably fix the antibacterial and mildew-proof components on the surface of phosphogypsum particles, so that the modified phosphogypsum maintains excellent thermal insulation properties. The thermal insulation effect of the material is further enhanced by surface modification and the reasonable ratio of the composite material. It also has good environmental adaptability and is particularly suitable for use in humid, warm and other environments prone to mold growth, enabling it to work stably for a long time in a variety of environments. The present invention effectively solves the problem of insufficient stability and durability of phosphogypsum insulation materials in humid environments in the prior art, and improves its wide application and long-term use effect.

[0089] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for resource utilization of phosphogypsum as a thermal insulation material, characterized by: include: Screening of phosphogypsum raw materials to remove impurities; The screened phosphogypsum raw material is subjected to heat treatment to remove moisture and obtain phosphogypsum particles of uniform particle size; Dynamic temperature control technology is introduced during the heat treatment process to adjust the temperature based on the real-time moisture content monitoring. The dynamic temperature control technology includes a feedback regulation mechanism based on the real-time moisture content to optimize the matching of treatment temperature and time. The phosphogypsum particles are subjected to antibacterial and mildew-proof surface modification, and an antibacterial and mildew-proof component is bonded to the surface of the phosphogypsum particles. The antibacterial and mildew-proof component is a metal compound of silver, copper, or zinc. The mass ratio of the antibacterial and mildew-proof component to the phosphogypsum particles is 0.1% to 5%. The surface-modified phosphogypsum particles are mixed with other thermal insulation materials to obtain a composite material; The thermal insulation material comprises expanded perlite and a polymer-based material, wherein the mass ratio of the phosphogypsum particles to the expanded perlite is 3:1 to 7:1; The heat treatment temperature is 350° C. to 450° C., the treatment time is 1.5 hours to 2.5 hours, and the moisture content of the phosphogypsum particles is reduced to below 3%; The antibacterial and mildew-proof surface modification treatment adopts a sol-gel method, wherein silver ions, zinc ions or copper ion compounds are dissolved in a solution with a pH of 5 to 7, and react with the phosphogypsum particles to form an interfacial reaction to form a stable antibacterial layer; The surface coverage of the antibacterial and mildew-proof component is 70% to 95%.

2. The method for recycling phosphogypsum into a thermal insulation material according to claim 1, wherein: The mass ratio of the antibacterial and mildew-proof component is 0.5% to 3% of the phosphogypsum particles, and the antibacterial performance of the material is optimized by controlling the metal ion concentration.

3. The method for recycling phosphogypsum into a thermal insulation material according to claim 1, wherein: The mixing ratio of the composite material is 40% to 70% by mass of phosphogypsum particles, expanded perlite, and polymer-based material: 10% to 30% by mass: 10% to 20% by mass; forming the composite material through a mold to obtain a thermal insulation material board or block of a desired shape; The mold forming process includes compression molding or injection molding, with a pressure of 5MPa to 20MPa and a molding temperature of 40°C to 80°C.

4. The method for recycling phosphogypsum into a thermal insulation material according to claim 3, characterized in that: The composite material after mold forming is dried and cured; The drying temperature is 40°C to 70°C and the curing time is 4 to 12 hours; The curing process was carried out in an environment with a relative humidity of 40% to 60%, and the density of the resulting composite material was 0.3g / cm 3 Up to 1.5g / cm 3 .

5. The method for recycling phosphogypsum into a thermal insulation material according to claim 4, characterized in that: The polymer-based material is polyurethane or polystyrene, which is uniformly dispersed and forms a stable microstructure through a blending method.

6. The method for recycling phosphogypsum as a thermal insulation material according to claim 1, characterized in that: The dynamic temperature control technology in the heat treatment process achieves precise temperature control by monitoring the real-time moisture content, and dynamically adjusts the temperature range of the heat treatment through feedback.

Images