Inorganic radiation refrigeration coating with zinc tailings-prepared secondary zinc oxide as filler, coating and preparation method of inorganic radiation refrigeration coating

Abstract

The invention relates to the technical field of solid waste high-value reutilization, and discloses an inorganic radiation refrigeration coating with zinc tailings prepared secondary zinc oxide as a filler, a coating and a preparation method thereof.The preparation method of the inorganic radiation refrigeration coating with zinc tailings prepared secondary zinc oxide as the filler comprises the following steps that a zinc tailings raw material is subjected to ball milling treatment and sieving, and a powder material is obtained; drying to obtain reaction precursor powder; sintering the reaction precursor powder to obtain a secondary zinc oxide primary reaction product; the secondary zinc oxide primary reaction product is subjected to ball milling, sieving and drying, and the secondary zinc oxide radiation refrigeration powder filler is obtained; and mixing the secondary zinc oxide radiation refrigeration powder filler with other components, and stirring to obtain the inorganic radiation refrigeration coating taking the secondary zinc oxide prepared from the zinc tailings as the filler. The invention provides a method for preparing an inorganic radiation refrigeration coating and a coating from zinc hypoxide prepared by solid waste conversion of zinc tailings. The coating and the coating provided by the invention have good environmental cooling characteristic and long-term stable working capability.

Description

Technical Field

[0001] This invention relates to the field of high-value reuse technology of solid waste, and in particular to an inorganic radiation cooling coating, coating material and preparation method thereof using zinc oxide produced from zinc tailings as filler. Background Technology

[0002] With the accelerating rate of resource consumption, energy conservation and waste recycling have become two key factors for sustainable development on Earth. Building energy consumption accounts for more than 40% of global total energy consumption, of which refrigeration accounts for nearly 20-30%. Active cooling methods (such as air conditioners, fans, pumps, or chillers) not only consume huge amounts of energy but also exacerbate greenhouse gas emissions. This further intensifies the future demand for cooling capacity in human society. Therefore, new zero-energy and green cooling methods are crucial for mitigating the greenhouse effect and achieving energy conservation and emission reduction.

[0003] Benefiting from the principles of zero energy consumption and passive cooling, radiation cooling is a technology that is expected to be applied on a large scale to reduce energy consumption. Radiation cooling technology is a zero-energy passive cooling technology that reduces the temperature of an object by reducing the absorption of incident sunlight and emitting the object's own energy into outer space in the form of electromagnetic waves. Therefore, the cooling process is characterized by being completely spontaneous and requiring no external energy input. The main ways in which materials achieve cooling effects through radiation cooling include: (1) reducing solar energy input through Mie scattering, metal reflective layers and / or Bragg reflectors; (2) dissipating heat energy through the vibration of functional groups with strong infrared emission capabilities at atmospheric windows. Building envelope coatings with radiation cooling function have good practical application value in reducing building cooling energy consumption. However, the radiation cooling coatings that have been disclosed so far have disadvantages such as complex preparation processes, high costs and insufficient environmental weather resistance, which greatly limits the practical application feasibility of radiation cooling coatings.

[0004] On the one hand, research indicates that the high price of radiation-cooling active fillers, which are widely used in reported coatings, is the main reason for the high price of radiation-cooling coatings. Currently, high-purity oxides and nitrides with nanoscale dimensions are widely used as active fillers in radiation cooling, such as commercially available silica (hollow microspheres) (CN 115785809 A), nano-titanium dioxide powder (CN 120648141 A), nano-zinc oxide powder (CN 120648346 A), nano-alumina powder (CN 119875506 A), rare earth oxide powder (CN 117567894 B, CN117567877 B), nano-borate (CN116004026 A), and nano-silicon nitride (CN 120310398 A, CN 119875506 A), and nano-boron nitride (CN120648346 A). A) Nitrided powders require complex chemical processes to produce, which increases the cost of coatings.

[0005] On the other hand, binders are an indispensable component for achieving adhesion between coatings and substrates. Currently reported radiative cooling coatings mainly use organic polymer binders, such as fluorosilicone resin (CN 118027812 A), fluorocarbon resin (CN118638456 A), polyacrylic resin (CN 115558348 A), polystyrene-acrylic resin (CN 120623843 A), polyurethane resin (CN 119505673 A), waterborne aldehyde-ketone resin (CN 119490780 A), and epoxy resin (CN 120137486). A) During long-term service (especially under prolonged direct sunlight), the polymer chains of polymer binders break down, causing degradation of coating performance. This is the main reason for the performance degradation of polymer binder-based radiation cooling coatings. Inorganic binders have high chemical bond strength and strong environmental stability, so using inorganic binders will greatly improve the environmental weather resistance of radiation cooling coatings. Currently, among the published patents, only those using hydrolyzed silica sol or hydrolyzed organosilicon components as binders (CN 119875506A, CN 117567894 A, CN 118006155 A) have achieved the preparation of inorganic radiation cooling coatings. However, high-temperature treatment (>400℃) is required to achieve adhesion between the coating and the substrate, which limits the practical value of this coating technology. Therefore, developing new material synthesis technologies and coating compositions to prepare low-cost, high-environmentally-resistant radiation cooling coatings has great practical value in reducing building cooling energy consumption.

[0006] Zinc tailings refer to solid waste generated during zinc ore beneficiation, containing a certain amount of zinc oxide, silicates, aluminates, and other components. Roasting zinc tailings with a zinc content of 30-60% to obtain zinc oxide powder is an effective means of reusing zinc tailings. Currently, zinc oxide is mainly used in the processing of electrolytic zinc or zinc oxide, a process that suffers from high energy consumption, pollution, and incomplete utilization of zinc oxide components. Given that the zinc oxide, silicates, and aluminates in zinc oxide possess excellent radiative cooling properties, using zinc oxide powder as a filler to prepare radiative cooling coatings for building envelopes offers advantages such as low energy consumption, simple technical processes, and high-value reuse. Therefore, converting inexpensive zinc tailings into zinc oxide radiative cooling fillers to construct radiative cooling coatings for building envelopes can achieve high-value utilization of solid waste and reduce building cooling energy consumption, which is of great significance for my country's resource recycling, improved energy efficiency, and green and sustainable economic and social development. Summary of the Invention

[0007] The purpose of this invention is to provide an inorganic radiation cooling coating using zinc oxide produced from zinc tailings as filler and its preparation method, overcoming the shortcomings of existing radiation cooling materials such as complex processes and high costs, and realizing the high-value conversion and utilization of solid waste.

[0008] To achieve the above objectives, this invention provides a method for preparing an inorganic radiation-cooling coating using zinc oxide produced from zinc tailings as a filler, comprising the following steps: Step S1: The zinc tailings raw material is ball-milled, sieved, and dried to obtain the reaction precursor powder; Step S2: The reaction precursor powder is sintered at 900-1300℃ for 10-15h to obtain the primary reaction product of zinc oxide. Step S3: The primary reaction product of zinc oxide is ball-milled and sieved to obtain powder with a particle size of 1000-2800 mesh, and dried to obtain zinc oxide radiation cooling powder filler; Step S4: Mix the zinc oxide radiation cooling powder filler, inorganic compound auxiliary powder, silicate water glass, water and coating additives in proportion and stir to obtain an inorganic radiation cooling coating with zinc oxide produced from zinc tailings as filler.

[0009] Preferably, in step S1, the ball milling conditions are: ball milling speed of 500-3000 r / min, ball milling time of 0.5-4 h; and the sieve mesh size of 200-3000 mesh.

[0010] Preferably, in step S3, the zinc oxide radiation-cooled powder filler has a hexagonal wurtzite crystal structure.

[0011] Preferably, in step S4, the inorganic compound auxiliary powder includes at least one of silicon dioxide, titanium dioxide, aluminum oxide, calcium carbonate, calcium sulfate, silicon nitride, and boron nitride.

[0012] Preferably, in step S4, the silicate water glass includes at least one of lithium silicate, sodium silicate, and potassium silicate; and the coating additive includes at least one of organosilicon and mineral oil.

[0013] Preferably, in step S4, the mass ratio of the zinc oxide radiation cooling powder filler, the inorganic compound auxiliary powder, the silicate water glass, the water, and the coating additive is (20-25):(10-15):(25-30):(5-10):(0.1-1).

[0014] Preferably, in step S4, the stirring conditions are: a stirring rate of 200-800 r / min and a stirring time of 0.5-24 h.

[0015] The inorganic radiation cooling coating with zinc oxide produced from zinc tailings as filler was prepared by the aforementioned method.

[0016] This invention also discloses an inorganic radiation-cooling coating prepared by an inorganic radiation-cooling coating using zinc oxide produced from zinc tailings as filler. The coating is prepared by the following method: the inorganic radiation-cooling coating is applied to the surface of a building envelope material substrate by brushing, spraying, or casting to obtain a wet coating, and the wet coating is dried and cured to obtain the inorganic radiation-cooling coating.

[0017] Furthermore, the thickness of the inorganic radiation cooling coating is 0.1-5mm; the building envelope materials include wood panels, color steel tiles, waterproof bricks, cement boards, metal material boards, concrete slabs, and fiber-reinforced composite material boards.

[0018] Furthermore, the inorganic radiation-cooling coating has a reflectivity of 88-94% in the solar spectral band (250-2500nm), an infrared emissivity of 90-95% in the atmospheric window spectral band (2-25μm), and a cooling efficiency of 75-110W / m. 2 .

[0019] The inorganic radiation cooling coating or inorganic radiation cooling coating with zinc oxide produced from zinc tailings as filler is used in the thermal management of buildings, data centers, cold chain transportation, automotive surfaces or outdoor equipment.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention uses zinc oxide powder prepared from zinc tailings as the core filler for a radiation-cooling coating. Zinc oxide contains defects such as oxygen vacancies and zinc interstitials. These defects form localized states or dangling bonds in the crystal, achieving high solar spectral reflectivity and high atmospheric window infrared emissivity. The high-density oxygen vacancies inherent in zinc oxide can spontaneously build a polarization network within the crystal lattice, "resonating" out the 8-13μm thermal radiation, while almost not absorbing the solar spectrum, easily achieving a 0.3-2μm reflectivity of over 94%. These oxygen vacancies also bridge each other to form a flexible three-dimensional framework, which expands to 4×10⁻⁻⁻⁴ during thermal expansion. 6 K⁻¹, zero cracks even after thousands of cycles at −40-120°C; when exposed to ultraviolet light, the vacancy self-repairs, and the optical decay is less than 3% after 20 years of outdoor exposure, providing a lightweight and long-lasting passive cooling solution for green buildings, photovoltaic backsheets, high-temperature storage tanks, etc. 2. This invention, through the synergistic effect of mechatronics and thermochemistry, completely avoids the use of organic solvents and high energy consumption in the preparation process of fillers for common radiation cooling coatings, achieving efficient conversion of solid waste raw materials and significantly reducing equipment costs. The entire process of preparing the inorganic radiation cooling coating of this invention achieves zero wastewater discharge, providing an efficient and low-carbon green solution for solid waste resource utilization. Furthermore, the radiation cooling coating of this invention is composed entirely of inorganic materials, possessing high environmental weather resistance, good ease of construction, and green environmental compatibility. Using solid waste zinc tailings as raw materials and simplifying the process design, the overall cost of the radiation cooling coating is only 20-30% of that of traditional radiation cooling materials, possessing the potential for large-scale industrial production. It also has significant application value in the thermal management of buildings, data centers, cold chain transportation, automotive surfaces, or outdoor equipment. 3. The radiation cooling coating prepared by the coating described in this invention has high environmental weather resistance. After one year of exposure to the outdoor environment, the solar absorptivity decreases by only 12%; while the radiation cooling coating prepared by a typical high-molecular polymer binder (polystyrene-acrylic emulsion) with high environmental weather resistance decreases by 28% after one year of exposure to the outdoor environment. Attached Figure Description

[0021] Figure 1 This is the XRD pattern of the zinc oxide radiation-cooled powder filler in Example 1 of the present invention; Figure 2 This is a SEM image of the zinc oxide radiation-cooled powder filler in Example 1 of the present invention; Figure 3 This is a physical image of the inorganic radiation cooling coating prepared in Example 3 of the present invention; Figure 4 The solar reflectance spectrum of the inorganic radiation cooling coating prepared in Example 3 of this invention in the 250-2500 nm wavelength range; Figure 5The infrared emission spectrum of the inorganic radiation-cooling coating prepared in Example 3 of this invention in the 2-25 μm band; Figure 6 The solar reflectance spectrum of the inorganic radiation cooling coating prepared in Example 4 of this invention in the 250-2500 nm wavelength range; Figure 7 The infrared emission spectrum of the inorganic radiation-cooling coating prepared in Example 4 of this invention in the 2-25 μm band; Figure 8 The solar reflectance spectrum of the inorganic radiation cooling coating prepared in Comparative Example 3 of the present invention in the 250-2500 nm wavelength range; Figure 9 The infrared emission spectrum of the inorganic radiation-cooling coating prepared in Comparative Example 3 of the present invention in the 2-25 μm band is shown. Figure 10 This is a physical image of the inorganic radiation cooling coating prepared in Comparative Example 4 of the present invention. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention. Example 1

[0023] This embodiment discloses a method for preparing an inorganic radiation-cooling coating using zinc oxide produced from zinc tailings as a filler, comprising the following steps: Step S1: Add zinc tailings raw material into a ball mill jar and use a ball mill to crush the zinc tailings. Grind at 800 r / min for 4 hours and then sieve through a 400 mesh screen to obtain the reaction precursor powder. Step S2: Add the reaction precursor powder to the crucible, transfer it to the muffle furnace, set the heating rate to 5 ℃ / min, heat to 1100 ℃, and hold for 12 h to obtain the primary reaction product of zinc oxide. Step S3: Add the primary reaction product of zinc oxide to a ball mill, use ethanol as the ball milling lubricant, grind at 800 r / min for 12 h, dry to remove the ethanol solution, sieve through a 1000 mesh sieve and dry to obtain powder, and further dry the powder to obtain zinc oxide radiation cooling powder filler. Step S4: Add zinc oxide radiation cooling powder filler, potassium silicate water glass with a modulus of 3.1-3.4, water and mineral oil to a container in a mass ratio of 30:25:5:0.1, and stir at 800 r / min for 1 h to obtain an inorganic radiation cooling coating with zinc oxide produced from zinc tailings as filler. Example 2

[0024] This embodiment discloses a method for preparing an inorganic radiation-cooling coating using zinc oxide produced from zinc tailings as a filler, comprising the following steps: Step S1: Add zinc tailings raw material into a ball mill jar and use a ball mill to crush the zinc tailings. Grind at 1000 r / min for 8 hours and then sieve through a 1200 mesh screen to obtain the reaction precursor powder. Step S2: Add the reaction precursor powder to the crucible, transfer it to the muffle furnace, set the heating rate to 5℃ / min, heat to 1000℃, and hold for 12h to obtain the primary reaction product of zinc oxide. Step S3: Add the primary reaction product of zinc oxide to a ball mill, use ethanol as the ball milling lubricant, grind at 800 r / min for 12 h, dry to remove the ethanol solution, sieve through a 1200 mesh sieve and dry to obtain powder, and further dry the powder to obtain zinc oxide radiation cooling powder filler. Step S4: Add zinc oxide radiation cooling powder filler, commercially available 500nm titanium dioxide powder filler, commercially available 300nm silica powder filler, potassium silicate water glass with a modulus of 3.1-3.4, sodium silicate water glass with a modulus of 3.1-3.4, water and mineral oil to a container in a mass ratio of 20:5:5:15:10:5:0.1, and stir at 800 r / min for 1 h to obtain an inorganic radiation cooling coating with zinc oxide produced from zinc tailings as filler. Example 3

[0025] This embodiment discloses a method for preparing an inorganic radiation-cooling coating, as detailed below: The inorganic radiation cooling coating prepared in Example 1, which uses zinc oxide from zinc tailings as filler, was applied to the surface of a clean aluminum sheet and a wooden building envelope material substrate by brushing to obtain a wet coating. After the wet coating was dried in air at room temperature for 30 hours to remove water, the inorganic radiation cooling coating was obtained. The inorganic radiation cooling coating has good adhesion to the substrate, is white, and has a thickness of 0.3 mm. Example 4

[0026] This embodiment discloses a method for preparing an inorganic radiation-cooling coating, as detailed below: The inorganic radiation cooling coating prepared in Example 2, which uses zinc oxide from zinc tailings as filler, was applied to the surface of a clean aluminum sheet and a wooden building envelope material substrate by spraying to obtain a wet coating. After the wet coating was dried in room temperature air for 30 hours to remove water, the inorganic radiation cooling coating was obtained. The inorganic radiation cooling coating has good adhesion to the substrate, is white, and has a thickness of 0.2 mm.

[0027] Comparative Example 1 This comparative example discloses a method for preparing an inorganic radiation-cooling coating, as detailed below: Commercial zinc oxide radiation cooling powder filler with a mesh size of 1200, potassium silicate water glass with a modulus of 3.1-3.4, water and mineral oil were added to a container in a mass ratio of 30:25:5:0.1 and stirred at 800 r / min for 1 h to obtain an inorganic radiation cooling coating.

[0028] Comparative Example 2 This comparative example discloses a method for preparing an inorganic radiation-cooling coating using zinc oxide derived from zinc tailings as a filler, comprising the following steps: Step S1: Add zinc tailings raw material into a ball mill jar and use a ball mill to crush the zinc tailings. Grind at 800 r / min for 4 hours and then sieve through a 400 mesh screen to obtain the reaction precursor powder. Step S2: Add the reaction precursor powder to the crucible, transfer it to the muffle furnace, set the heating rate to 5℃ / min, heat to 1100℃, and hold for 12h to obtain the primary reaction product of zinc oxide. Step S3: Add the primary reaction product of zinc oxide to a ball mill, use ethanol as the ball milling lubricant, grind at 800 r / min for 12 h, dry to remove the ethanol solution, sieve through a 1000 mesh sieve and dry to obtain powder, and further dry the powder to obtain zinc oxide radiation cooling powder filler. Step S4: Add zinc oxide radiation cooling powder filler, polystyrene-acrylic emulsion, water and mineral oil to a container at a mass ratio of 30:25:5:0.1, and stir at 800 r / min for 1 h to obtain an inorganic radiation cooling coating with zinc oxide produced from zinc tailings as filler.

[0029] Comparative Example 3 This comparative example discloses a method for preparing an inorganic radiation-cooling coating, as follows: The inorganic radiation cooling coating prepared in Comparative Example 1 was applied to the surface of a clean aluminum sheet and a wooden building envelope material substrate by spraying to obtain a wet coating. After the wet coating was dried in room temperature air for 30 hours to remove water, an inorganic radiation cooling coating was obtained. The inorganic radiation cooling coating has good adhesion to the substrate, is white, and has a thickness of 0.2 mm.

[0030] Comparative Example 4 This comparative example discloses a method for preparing an inorganic radiation-cooling coating, as follows: An inorganic radiation cooling coating, prepared in Comparative Example 2 and using zinc oxide from zinc tailings as filler, was applied to the surface of a clean aluminum sheet and a wooden building envelope material substrate by brushing to obtain a wet coating. The wet coating was dried in room temperature air for more than 48 hours to obtain an inorganic radiation cooling coating. The inorganic radiation cooling coating has good adhesion to the substrate, is white, and has a thickness of 0.2 mm.

[0031] Experimental Example Test 1: XRD and SEM analyses were performed on the zinc oxide radiation-cooled powder filler prepared in Example 1. The results are as follows: Figure 1-2 As shown; Test 2, Solar Reflectivity: The solar reflectivity of the inorganic radiation-cooling coatings prepared in Examples 3-4 and Comparative Examples 3-4 was tested in the wavelength range of 250-2500 nm according to the standard ASTM C 1549-09 (2014). Test 3, Infrared Emissivity: The infrared emissivity of the inorganic radiation-cooling coatings prepared in Examples 3-4 and Comparative Examples 3-4 was tested in accordance with standard GB / T 4653-1984 in the wavelength range of 2.5-25 μm. Test 4. Cooling performance: The cooling efficiency of the inorganic radiation cooling coatings prepared in Examples 3-4 and Comparative Examples 3-4 was tested to characterize their cooling performance. Test 5, Weather Resistance: The inorganic radiation cooling coatings prepared in Examples 3-4 and Comparative Examples 3-4 were exposed to the outdoor environment for one year, and the solar spectral reflectance of the coatings after exposure was tested according to the method in Test 2.

[0032] The test results for tests two, three, four, and five are shown in Table 1. Figure 4-9 As shown: Table 1 Solar reflectance / % <![CDATA[Cooling efficiency / (W / m 2 )]]> Infrared emissivity / % The decrease in solar spectral reflectance after one year of outdoor environmental exposure / % Example 3 ≥91 93 ≥93 12 Example 4 ≥94 103 ≥94 8.2 Comparative Example 3 ≥90 89 ≥91 15 Comparative Example 4 ≥92 91 ≥91 28 From Table 1, Figure 4-9 The test results show that: The inorganic radiation cooling coatings prepared in Examples 3-4 of this invention have better radiation cooling performance and weather resistance; Compared with Example 3, Example 4 added nano-titanium dioxide and silicon dioxide to the inorganic radiation coating. The addition of nano-titanium dioxide enhanced the reflectivity of the coating to incident light, thereby increasing the reflectivity of sunlight. The Ti-O bond vibration signal in nano-titanium dioxide is located in the 8-13μm band, so the addition of titanium dioxide improved the infrared emissivity of the coating. In addition, nano-titanium dioxide has high environmental stability, which improves the weather resistance of the coating. Compared with Example 3, the inorganic radiation cooling coating of Comparative Example 3 has lower radiation cooling performance and weather resistance. This is because commercial ZnO filler has strong ultraviolet excitation characteristics and low environmental stability. Compared with Example 3, the weather resistance of the inorganic radiation cooling coating of Comparative Example 4 was significantly reduced because the polymer binder under ultraviolet excitation caused polymer chain breakage under outdoor conditions, resulting in lower environmental stability.

[0033] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing an inorganic radiation-cooling coating using zinc oxide produced from zinc tailings as a filler, characterized in that, Includes the following steps: Step S1: The zinc tailings raw material is ball-milled, sieved, and dried to obtain the reaction precursor powder; Step S2: The precursor powder is sintered at 900-1300℃ for 10-15h to obtain the primary reaction product of zinc oxide. Step S3: The primary reaction product of zinc oxide is ball-milled and sieved to obtain powder with a particle size of 1000-2800 mesh, and dried to obtain zinc oxide radiation cooling powder filler; Step S4: Mix the zinc oxide radiation cooling powder filler, inorganic compound auxiliary powder, silicate water glass, water and coating additives in proportion and stir to obtain an inorganic radiation cooling coating with zinc oxide produced from zinc tailings as filler.

2. The method for preparing an inorganic radiation-cooling coating using zinc oxide produced from zinc tailings as filler according to claim 1, characterized in that, In step S1, the ball milling conditions are: ball milling speed of 500-3000 r / min, ball milling time of 0.5-4 h; and the sieve mesh size of 200-3000 mesh.

3. The method for preparing an inorganic radiation-cooling coating using zinc oxide produced from zinc tailings as filler according to claim 1, characterized in that, In step S3, the zinc oxide radiation cooling powder filler has a hexagonal wurtzite crystal structure.

4. The method for preparing an inorganic radiation-cooling coating using zinc oxide produced from zinc tailings as filler according to claim 1, characterized in that, In step S4, the inorganic compound auxiliary powder includes at least one of silicon dioxide, titanium dioxide, aluminum oxide, calcium carbonate, calcium sulfate, silicon nitride, and boron nitride.

5. The method for preparing an inorganic radiation-cooling coating using zinc oxide produced from zinc tailings as filler according to claim 1, characterized in that, In step S4, the silicate water glass includes at least one of lithium silicate, sodium silicate, and potassium silicate; the coating additive includes at least one of organosilicon and mineral oil.

6. The method for preparing an inorganic radiation-cooling coating using zinc oxide produced from zinc tailings as filler according to claim 1, characterized in that, In step S4, the mass ratio of the zinc oxide radiation cooling powder filler, inorganic compound auxiliary powder, silicate water glass, water and coating additive is (20-25):(10-15):(25-30):(5-10):(0.1-1).

7. An inorganic radiation cooling coating prepared using the method described in any one of claims 1-6, which uses zinc oxide produced from zinc tailings as filler, as an inorganic radiation cooling coating.

8. An inorganic radiation-cooling coating prepared from the inorganic radiation-cooling coating of claim 7, using zinc oxide produced from zinc tailings as filler, characterized in that, The inorganic radiation cooling coating is prepared by applying it to the surface of a building envelope material substrate by brushing, spraying, or casting to obtain a wet coating. The wet coating is then dried and cured to obtain the inorganic radiation cooling coating.

9. The inorganic radiation cooling coating according to claim 8, characterized in that, The thickness of the inorganic radiation cooling coating is 0.1-5mm; the building envelope materials include wood panels, color steel tiles, waterproof bricks, cement boards, metal material boards, concrete boards, and fiber-reinforced composite material boards.

10. The application of the inorganic radiation cooling coating with zinc oxide produced from zinc tailings as filler as described in claim 7 or the inorganic radiation cooling coating as described in claim 8 in the thermal management of buildings, data centers, cold chain transportation, automotive surfaces or outdoor equipment.

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