Method for preparing calcium magnesium silicate radiation refrigeration coating based on yellow phosphorus slag
By preparing magnesium calcium silicate radiation cooling coating, the problems of yellow phosphorus slag accumulation and pollution were solved, realizing the high-value reuse of yellow phosphorus slag and reducing building energy consumption. The coating has low cost and good weather resistance.
Patent Information
- Application Number
- CN202511191502.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-25
- Publication Date
- 2025-11-14
AI Technical Summary
The problems of yellow phosphorus slag accumulation and pollution have not been effectively solved, and traditional radiative cooling materials are costly and difficult to achieve green and sustainable development.
Tetragonal magnesium calcium silicate powder was prepared by mixing yellow phosphorus slag with magnesium oxide and sintering it at 800~1200℃. Radiation cooling coating was prepared by combining it with additives such as aluminum dihydrogen phosphate and then coated onto the substrate surface to form a radiation cooling coating.
It achieves high-value reuse of yellow phosphorus slag, reduces building energy consumption, reduces soil and water pollution, and the cost of the coating is only 20%-30% of that of traditional materials, with better weather resistance than organic resin-based coatings.
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Figure CN120944390A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of radiation cooling materials technology, specifically to a method for preparing magnesium calcium silicate radiation cooling coatings based on yellow phosphorus slag. Background Technology
[0002] With population growth and rapid social development, building energy consumption accounts for an increasingly larger proportion of total social energy consumption. Currently, building energy consumption accounts for more than 35% of China's total energy consumption, and air conditioning systems account for more than half of the overall building energy consumption. Currently, southern my country experiences high average temperatures and hot summers, with air conditioning accounting for approximately 80% of the total annual air conditioning energy consumption. Therefore, developing new low-energy cooling models is beneficial for reducing building energy consumption, improving my country's energy efficiency, and promoting the development of green industries. Radiative cooling is a novel zero-energy passive cooling technology. Related materials reduce heat absorption by reflecting the solar spectrum, while simultaneously transferring heat to the low-temperature outer space through their own thermal radiation within the 8-13 μm spectral wavelength range of the atmospheric window. These two mechanisms work together to lower the material's own temperature. Therefore, building coatings with radiative cooling function have considerable economic value and green energy-saving significance in reducing building energy consumption, and have been extensively and deeply studied. In the composition of radiative cooling coatings, inorganic fillers with irregular shapes are crucial. It reduces the absorption of solar heat by scattering incident solar photons, thereby suppressing the building's heat absorption and temperature rise under sunlight, and achieving passive zero-energy cooling of the building.
[0003] On the other hand, with the sound development of my country's economy and industry, the output and demand of China's yellow phosphorus industry began to recover from 2020. In the first half of 2024, China's yellow phosphorus output was 295,200 tons, an increase of 3.19% year-on-year. Yellow phosphorus slag is a by-product of the electric furnace method for producing yellow phosphorus, with annual emissions reaching millions of tons. Its main components are compounds such as SiO2, CaO, and Al2O3, and it also contains small amounts of MgO, Fe2O3, and P2O5. As a major producer of yellow phosphorus, my country produced approximately 8.5 million tons of yellow phosphorus slag in 2023, of which more than 90% was landfilled, with a utilization rate of less than 10%. This not only occupies a large amount of land resources, but also causes soil and water pollution due to the harmful elements such as fluorine and phosphorus it contains, harming the ecological environment. With my country's increasing emphasis on energy conservation and emission reduction, green development has become the key to sustainability in all industries and an important development direction for the mining and chemical industries. The development plans and policies for the phosphate industry are also mainly centered around the industry's green transformation, reducing pollution emissions, and reusing yellow phosphorus slag. Benefiting from the low cost and high content of SiO2, Al2O3 and other radiation-cooling active components in yellow phosphorus slag, a new preparation technology can be developed to transform yellow phosphorus slag into radiation-cooling materials with high solar spectral reflectivity and high atmospheric window infrared emissivity. This can synergistically realize the green and sustainable development strategy of value-added reuse of yellow phosphorus slag solid waste and reduction of building cooling energy consumption. Summary of the Invention
[0004] The purpose of this invention is to provide a method for preparing magnesium calcium silicate radiation cooling coatings based on yellow phosphorus slag, achieving high-value reuse of solid waste. The coatings of this invention are easy to produce, have significant cost advantages, and show promising application prospects in the construction industry.
[0005] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution: A method for preparing magnesium calcium silicate radiation cooling coating based on yellow phosphorus slag includes the following steps: S1: Mix yellow phosphorus slag and magnesium oxide in a weight ratio of (2:1) to (10:1) and ball mill to obtain precursor powder; S2: Sinter the precursor powder at 800~1200℃ for 4~12 hours to generate the primary reaction product of magnesium calcium silicate; S3: The primary reaction product is ball-milled and sieved to obtain magnesium calcium silicate radiation cooling powder material with a particle size of 800~4000 mesh; S4: Mix aluminum dihydrogen phosphate, magnesium calcium silicate powder and water in a mass ratio of (1:2:1) to (1:3:2), add dispersant, wetting agent, leveling agent and defoamer, and stir evenly to obtain radiation cooling coating; S5: Apply the radiation-cooling coating to the surface of a solid substrate to form a wet coating, and obtain the radiation-cooling coating after drying.
[0006] Furthermore, in step S1, the ball milling speed is 400~800 r / min, and the ball milling time is 0.5~3 hours.
[0007] Furthermore, the magnesium calcium silicate powder material has a tetragonal crystal structure.
[0008] Furthermore, the dispersant is one or more of sodium polyacrylate, hexadecyltrimethylammonium bromide, polyoxyethylene ether, and polyacrylic acid, and the amount added is 0.2 to 2 wt% of the total mass of the coating.
[0009] Furthermore, the wetting agent is one or more of sulfate ester salts, polyoxyethylene ethers, betaine, and polyether-modified silicone oil, and the amount added is 0.3 to 2 wt% of the total mass of the coating.
[0010] Furthermore, the leveling agent is one or more of the following: silicone, acrylic, fluorocarbon, and polyurethane, and the amount added is 0.5 to 3 wt% of the total mass of the coating.
[0011] Furthermore, the defoamer is one of organosilicon, polyether, or mineral oil, and the amount added is 0.6 to 3 wt% of the total mass of the coating.
[0012] Furthermore, the solid substrate is a stainless steel plate, aluminum plate, ceramic tile, or wood board, which is sanded with sandpaper and then cleaned with deionized water and anhydrous ethanol in sequence before coating.
[0013] Furthermore, the drying conditions are drying in air at 20~50℃ for 10min~10h.
[0014] Furthermore, the thickness of the radiation cooling coating is 200~800μm.
[0015] Furthermore, the obtained radiation-cooling coating has a reflectivity of 85%–95% in the solar spectrum and an infrared emissivity of 93%–97% in the 8–13 μm atmospheric window band.
[0016] Furthermore, after the radiation-cooling coating is kept in a 95% RH humidity environment for 48 hours, the solar spectral reflectance is 85.6%~96%.
[0017] The beneficial effects of this invention are: This invention uses yellow phosphorus slag as raw material, whose main components are SiO2, CaO, and Al2O3. By controlling its solid-state reaction with magnesium oxide, tetragonal magnesium calcium silicate powder is synthesized under sintering conditions of 800-1200℃. This transforms industrial solid waste into a mineral material with radiative cooling capabilities, solving the soil / water pollution problem caused by yellow phosphorus slag landfill. The raw material cost is only 20%-30% of that of traditional radiative cooling materials, due to the zero-cost nature of yellow phosphorus slag and the simplified design of the solid-state reaction process, eliminating the need for wet purification steps and achieving a resource recycling model of "waste replacing ore".
[0018] The tetragonal crystal structure of magnesium calcium silicate powder forms a multi-scale light scatterer, such as... Figure 3 SEM reveals irregular particles that achieve a high reflectivity of 85%–95% in the solar spectrum through refraction / reflection at the crystal interface. Simultaneously, the Mg-O-Si bonds and lattice vibrations generate strong infrared radiation in the atmospheric window band, resulting in an emissivity of 93%–97%. Using aluminum dihydrogen phosphate as a binder, the coating, based on the barrier effect of the inorganic network against water molecule penetration, maintains a solar reflectivity of 85.6%–96% after 48 hours of exposure in a humid and hot environment with 95% RH, significantly outperforming the weather resistance of organic resin-based coatings.
[0019] This invention utilizes the low-temperature solid-phase reaction to lower the melting temperature using impurities such as Fe2O3 / P2O5 in yellow phosphorus slag, resulting in greater energy savings compared to traditional silicate synthesis processes. The coating system achieves broad substrate adaptability through the compounding of specific additives: wetting agents reduce the surface tension of the coating to below the substrate's critical value, and leveling agents suppress brushing defects, ensuring a uniform film layer on substrates such as wood, ceramic tiles, and aluminum plates. The drying conditions are mild, requiring no high-temperature curing equipment, making it suitable for outdoor on-site application.
[0020] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description
[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0022] Figure 1 The X-ray diffraction pattern of yellow phosphorus slag in Example 1 of this invention is shown.
[0023] Figure 2 The X-ray diffraction pattern of the magnesium calcium silicate powder sample obtained by adding magnesium oxide to yellow phosphorus slag in Example 1 of this invention.
[0024] Figure 3This is a scanning electron microscope (SEM) image of the magnesium calcium silicate powder sample described in Example 1 of this invention.
[0025] Figure 4 This is a physical image of the magnesium calcium silicate powder described in Example 1 of the present invention.
[0026] Figure 5 This is a photograph of a coating sample made from the magnesium calcium silicate coating described in Example 1 of the present invention.
[0027] Figure 6 This is a solar spectral reflectance diagram of the coating sample made from the magnesium calcium silicate coating described in Example 1 of the present invention.
[0028] Figure 7 The infrared emissivity spectrum of the coating sample prepared by the magnesium calcium silicate coating described in Example 1 of this invention.
[0029] Figure 8 The solar spectral reflectance of the coating sample prepared by the magnesium calcium silicate coating described in Example 1 of this invention after being kept in an environment with a humidity of 95%RH for 48 hours.
[0030] Figure 9 This is a solar spectral reflectance diagram of the coating sample made from the magnesium calcium silicate coating described in Example 2 of the present invention.
[0031] Figure 10 The infrared emissivity spectrum of the coating sample prepared by the magnesium calcium silicate coating described in Example 2 of this invention. Detailed Implementation
[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0033] Example 1 This embodiment describes a method for preparing magnesium calcium silicate radiation cooling coating based on yellow phosphorus slag. Using yellow phosphorus slag as raw material and magnesium oxide as an additive, magnesium calcium silicate is synthesized through sintering. The method for preparing the magnesium calcium silicate radiation cooling coating is carried out according to the following steps: S1: Use a balance to weigh yellow phosphorus slag and magnesium oxide in a weight ratio of 10:1 and add them to a ball mill jar. Mix them using a ball milling device and grind them at 800 r / min for 6 hours to obtain a well-mixed precursor. S2: Magnesium calcium silicate product was prepared by sintering precursor powder. The precursor was added to a crucible, transferred to a muffle furnace, and heated to 1100 ℃ at a heating rate of 5 ℃ / min. The temperature was then held for 12 h to finally convert yellow phosphorus slag into the initial product of magnesium calcium silicate. S3: The initial product is ground into powder, sieved through a 1200-mesh sieve, and then dried to obtain magnesium calcium silicate radiation cooling powder material with a certain particle size, and then dried.
[0034] S4: Weigh aluminum dihydrogen phosphate, magnesium calcium silicate powder, and water in a mass ratio of 1:2:1 and add them to a glass beaker. Stir the mixture at 600 r / min. During the stirring process, add 1 wt% sodium polyacrylate and 2 wt% polyoxyethylene ether mixture as a dispersant, 0.5 wt% polyoxyethylene ether as a wetting agent, 2 wt% polyacrylic acid as a leveling agent, and 2 wt% mineral oil as a defoamer. Continue stirring for 60 min to obtain the inorganic coating. S5: Sand the wooden board and metal plate with sandpaper for 5 minutes, remove dirt with deionized water and anhydrous ethanol in sequence, and after drying, use a brush or spray gun to apply the coating prepared in step four to the surface of the wood and metal substrate to obtain a wet coating. Use a hot blower to dry the wet coating in the air for 1 hour to remove solvent water and obtain a radiation cooling coating.
[0035] In this embodiment, the relevant test data is as follows: (1) X-ray diffraction pattern of yellow phosphorus slag ( Figure 1 ); (2) X-ray diffraction pattern of magnesium calcium silicate powder sample obtained by adding magnesium oxide to yellow phosphorus slag and sintering ( Figure 2 ); (3) Scanning electron microscopy (SEM) images of magnesium calcium silicate powder samples ( Figure 3 ); (4) Actual picture of magnesium calcium silicate powder ( Figure 4 ); (5) A physical image of the magnesium calcium silicate radiation cooling coating. Figure 5 ); (6) The reflection curve of the magnesium calcium silicate radiation cooling coating, with an average reflectance of 91% ( Figure 6 ); (7) Emission curve of magnesium calcium silicate radiation cooling coating, with an average emissivity of 96% ( Figure 7 ); (8) The solar spectral reflectance curve of the magnesium calcium silicate radiation cooling coating described in Example 1 after being kept in an environment with a humidity of 95%RH for 48 hours, with an average reflectance of 89.8% ( Figure 8 ).
[0036] Example 2 This embodiment describes a method for preparing magnesium calcium silicate radiation cooling coating based on yellow phosphorus slag. Using yellow phosphorus slag as raw material and magnesium oxide as an additive, magnesium calcium silicate is synthesized through sintering. The method for preparing the magnesium calcium silicate radiation cooling coating is carried out according to the following steps: S1: Weigh a certain weight ratio of yellow phosphorus slag and magnesium oxide and mix them using a ball mill. Use a balance to weigh yellow phosphorus slag and magnesium oxide in a weight ratio of 10:2 and add them to the ball mill jar. Mix them using a ball mill and grind them at 1000 r / min for 12 hours to obtain a well-mixed precursor. S2: Magnesium calcium silicate product was prepared by sintering precursor powder. The precursor was added to a crucible, transferred to a muffle furnace, and heated to 1200 ℃ at a heating rate of 5 ℃ / min. The temperature was then held for 12 h to finally convert yellow phosphorus slag into the initial product of magnesium calcium silicate. S3: The initial product is ground into powder, sieved through a 4000-mesh sieve, and then dried to obtain magnesium calcium silicate radiation cooling powder material with a certain particle size, and then dried.
[0037] S4: Weigh aluminum dihydrogen phosphate, magnesium calcium silicate powder, and water in a mass ratio of 1:3:1 and add them to a glass beaker. Stir at 600 r / min using a stirrer. During the stirring process, add 1 wt% sodium polyacrylate as a dispersant, 0.5 wt% polyoxyethylene ether as a wetting agent, 2 wt% polyurethane as a leveling agent, and 2 wt% mineral oil as a defoamer in sequence. Continue stirring for 60 min to obtain an inorganic coating. S5: Sand the wooden board and metal plate with sandpaper for 5 minutes, remove the dirt with deionized water and anhydrous ethanol in turn, and after drying, use a brush or spray gun to apply the coating prepared in step four to the surface of the wood and metal substrate to obtain a wet coating. After drying the wet coating in air at 30°C for 12 hours to remove the solvent water, a radiation cooling coating is obtained.
[0038] In this embodiment, the relevant test data is as follows: (1) Reflectance curve of magnesium calcium silicate all-inorganic radiation cooling coating, with an average reflectance of 90% ( Figure 9 ); (2) Emission curve of the magnesium calcium silicate all-inorganic radiation cooling coating, with an average emissivity of 97% ( Figure 10 ).
[0039] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.
Claims
1. A method for preparing magnesium calcium silicate radiation cooling coating based on yellow phosphorus slag, characterized in that, Includes the following steps: S1: Mix yellow phosphorus slag and magnesium oxide in a weight ratio of (2:1) to (10:1) and ball mill to obtain precursor powder; S2: Sinter the precursor powder at 800~1200℃ for 4~12 hours to generate the primary reaction product of magnesium calcium silicate; S3: The primary reaction product is ball-milled and sieved to obtain magnesium calcium silicate radiation cooling powder material with a particle size of 800~4000 mesh; S4: Mix aluminum dihydrogen phosphate, magnesium calcium silicate powder and water in a mass ratio of (1:2:1) to (1:3:2), add dispersant, wetting agent, leveling agent and defoamer, and stir evenly to obtain radiation cooling coating; S5: Apply the radiation-cooling coating to the surface of a solid substrate to form a wet coating, and obtain the radiation-cooling coating after drying.
2. The method for preparing magnesium calcium silicate radiation cooling coating based on yellow phosphorus slag as described in claim 1, characterized in that: In step S1, the ball milling speed is 400~800 r / min, and the ball milling time is 0.5~3 hours.
3. The method for preparing magnesium calcium silicate radiation cooling coating based on yellow phosphorus slag as described in claim 1, characterized in that: The dispersant is one or more of sodium polyacrylate, hexadecyltrimethylammonium bromide, polyoxyethylene ether, and polyacrylic acid, and the amount added is 0.2 to 2 wt% of the total mass of the coating.
4. The method for preparing magnesium calcium silicate radiation cooling coating based on yellow phosphorus slag as described in claim 1, characterized in that: The wetting agent is one or more of sulfate ester salts, polyoxyethylene ethers, betaine, and polyether-modified silicone oil, and the amount added is 0.3~2wt% of the total mass of the coating.
5. The method for preparing magnesium calcium silicate radiation cooling coating based on yellow phosphorus slag as described in claim 1, characterized in that: The leveling agent is one or more of the following: silicone, acrylic, fluorocarbon, and polyurethane, and the amount added is 0.5 to 3 wt% of the total mass of the coating.
6. The method for preparing magnesium calcium silicate radiation cooling coating based on yellow phosphorus slag as described in claim 1, characterized in that: The defoamer is one of the following: organosilicon, polyether, or mineral oil, and the amount added is 0.6 to 3 wt% of the total mass of the coating.
7. The method for preparing magnesium calcium silicate radiation cooling coating based on yellow phosphorus slag as described in claim 1, characterized in that: The solid substrate is a stainless steel plate, aluminum plate, ceramic tile or wood board, which is sanded with sandpaper and then cleaned with deionized water and anhydrous ethanol in sequence before coating.
8. The method for preparing magnesium calcium silicate radiation cooling coating based on yellow phosphorus slag as described in claim 1, characterized in that: The drying conditions are drying in air at 20~50℃ for 10min~10h, and the thickness of the radiation cooling coating is 200~800μm.