A radiation-cooled glaze and its preparation method, and lightweight ceramic bricks.

Abstract

This invention belongs to the field of building ceramics technology, specifically disclosing a radiation-cooling glaze, its preparation method, and lightweight ceramic bricks. The radiation-cooling glaze comprises a base glaze and radiation-cooling powder, wherein the radiation-cooling powder comprises nanoporous alumina and magnesium aluminum spinel doped with metal oxides, the metal oxide being selected from at least one of ferric oxide, manganese dioxide, cobalt trioxide, and copper oxide. This invention uses a composite of nanoporous alumina and magnesium aluminum spinel doped with metal oxides as the radiation-cooling powder, adding it to the surface glaze of lightweight ceramic bricks. This not only achieves good glaze quality and brick shape but also improves the solar reflectance ratio of the glaze, thus realizing a good radiation-cooling effect. The solar reflectance reaches 88-94%, and the glaze quality and brick shape are excellent, with a surface flatness of ±0.3 mm.

Description

Technical Field

[0001] This invention belongs to the field of building ceramics technology, specifically relating to a radiation-cooled glaze and its preparation method, and lightweight ceramic bricks. Background Technology

[0002] With economic and social development, people are increasingly reliant on indoor environments and spending more and more time indoors. According to statistics from relevant institutions, urban residents in my country spend over 80% of their daily time indoors. Along with socio-economic development and rising demands for indoor comfort, the requirements for buildings are also rapidly increasing, especially in hot summer months when many cities experience the heat island effect, with urban temperatures generally about 5°C higher than suburban areas. This leads to a greater reliance on cooling equipment and a continuous increase in energy consumption. Therefore, developing energy-efficient and environmentally friendly cooling technologies is urgently needed to reduce the use of cooling equipment and alleviate its high energy consumption.

[0003] Lightweight ceramic tiles, characterized by their porous structure, light weight, and thermal insulation properties, are a new generation of green, energy-saving, and environmentally friendly building materials. They effectively reduce the load on floors, and their excellent thermal insulation performance allows them to be used as energy-saving building materials, reducing electricity consumption. Therefore, they can be widely used in interior and exterior building walls. Radiative cooling materials primarily work by controlling the optical properties of an object's surface to reflect solar heat and continuously radiate heat into the upper atmosphere through atmospheric windows, thereby effectively reducing the object's surface temperature and achieving a low-energy-consumption cooling effect. Therefore, applying a layer of radiative cooling glaze to the surface of lightweight ceramic tiles is an effective way to alleviate the high energy consumption of refrigeration equipment. Summary of the Invention

[0004] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a radiation-cooling glaze, its preparation method, and a lightweight ceramic brick. When the radiation-cooling glaze is applied to a lightweight body, it can effectively improve the solar reflectivity of the glaze surface while ensuring the quality of the glaze and the shape of the brick, thus achieving a good radiation-cooling effect.

[0005] To solve the above-mentioned technical problems, the first aspect of the present invention provides a radiation-cooled glaze, comprising a base glaze and a radiation-cooled powder, wherein the radiation-cooled powder comprises nanoporous alumina and magnesium aluminum spinel doped with metal oxides, and the metal oxides are selected from at least one of ferric oxide, manganese dioxide, cobalt oxide, and copper oxide.

[0006] Specifically, nanoporous alumina has a high infrared reflectivity. When infrared light shines on the surface of nanoporous alumina, some of the light is reflected back, while the rest penetrates into the particles. Inside the particles, the light undergoes multiple reflections and refractions. Due to the high reflectivity of alumina, most of the light inside the particles is also reflected back. Therefore, in the process of radiative cooling, nanoporous alumina can release heat through atmospheric windows in the form of infrared radiation, thereby achieving its own cooling effect. However, due to the high sintering temperature and coefficient of thermal expansion (8.0 × 10⁻⁶), nanoporous alumina... -6 -9.3×10 -6 K -1 The coefficients of thermal expansion (CPE) of the glaze are relatively high. If added directly to the glaze, too low a concentration will not achieve a good infrared light reflection effect; while too high a concentration will easily lead to insufficient firing of the glaze, affecting the glaze surface effect of the ceramic tile. Furthermore, it will cause the glaze to expand too much during firing due to the high coefficient of thermal expansion (CPE) of the lightweight body. -6 -7.6×10 -6 K -1 The mismatch causes deformation.

[0007] Based on this, this invention uses a composite of nanoporous alumina and metal oxide-doped magnesium aluminum spinel as a radiation cooling powder. Magnesium aluminum spinel can be used as a raw material for preparing ceramic glazes, not only without negatively impacting the glaze but also improving its mechanical properties. Simultaneously, magnesium aluminum spinel itself possesses certain optical properties. After doping with ferric oxide, manganese dioxide, cobalt oxide, and copper oxide, iron, manganese, cobalt, and copper ions enter the spinel's crystal structure, replacing some magnesium or aluminum ions, altering the original crystal structure, and forming doped magnesium aluminum spinel, significantly enhancing its light reflection effect. Furthermore, the doped magnesium aluminum spinel also has a lower melting temperature; adding it to glazes can effectively reduce the glaze's firing temperature. In addition, the coefficient of thermal expansion of metal oxide-doped magnesium aluminum spinel is 6.0 × 10⁻⁶. -6 -6.8×10 -6 K -1 The lower temperature coefficient of thermal expansion effectively balances the difference in thermal expansion coefficients between the nanoporous alumina and the lightweight body. Therefore, this invention replaces a portion of the nanoporous alumina with magnesium aluminum spinel doped with metal oxides, which not only achieves good glaze quality and brick shape, but also improves the solar reflectivity of the glaze, thereby achieving a good radiative cooling effect.

[0008] In some embodiments of the present invention, the doping amount of the metal oxide is 0.3-1 wt%. Ferric oxide, manganese dioxide, cobalt oxide, and copper oxide are all non-ferrous metal oxides, and their content in the glaze should not be too high.

[0009] In some embodiments of the present invention, the particle size of the nanoporous alumina is 20-50 nm.

[0010] In some embodiments of the present invention, the pore size of the nanoporous alumina is 2-20 nm.

[0011] In some embodiments of the present invention, the specific surface area of ​​the nanoporous alumina is 200-300 m². 2 / g. High specific surface area nano-alumina not only helps to improve the infrared reflectivity of alumina, but also helps to reduce the sintering temperature of alumina.

[0012] In some embodiments of the present invention, the mass ratio of nanoporous alumina in the radiation cooling powder is 50-70%. By adjusting the mass ratio of nanoporous alumina to magnesium aluminum spinel doped with metal oxides, the infrared reflectivity of the glaze can be improved while ensuring the quality of the glaze surface and the shape of the brick.

[0013] In some embodiments of the present invention, the mass ratio of the base glaze to the radiation-cooling powder is 100:(5-20). Adding a certain amount of radiation-cooling powder to the glaze improves its infrared reflectivity without affecting its performance.

[0014] In some embodiments of the present invention, the raw materials for preparing the base glaze include, by weight: 20-25 parts feldspar powder, 25-30 parts calcined kaolin, 20-25 parts quartz, 3-5 parts talc, 2-5 parts calcium carbonate, 2-5 parts dolomite, and 3-5 parts borax.

[0015] A second aspect of the present invention provides a method for preparing the above-mentioned radiation-cooled glaze, comprising the following steps:

[0016] The base glaze and radiation-cooled powder are subjected to wet ball milling to obtain the radiation-cooled glaze.

[0017] In some embodiments of the present invention, the specific gravity of the radiation-cooled glaze is 1.8-1.9 g / cm³. 3 .

[0018] A third aspect of the present invention provides a lightweight ceramic brick comprising a lightweight body and a surface glaze layer, the surface glaze layer being formed by firing the aforementioned radiation-cooled glaze.

[0019] In some embodiments of the present invention, the raw materials for preparing the lightweight preform include silicon carbide.

[0020] Specifically, during high-temperature firing of lightweight ceramic bricks, silicon carbide reacts to produce CO2 gas. Part of this CO2 gas forms a closed-cell structure within the ceramic brick, while some escapes through the glaze layer, easily leading to defects such as pinholes and bubbles on the glaze surface, thus affecting the glaze quality. The nanoporous alumina in the radiation-cooled glaze of this invention helps improve the sealing effect of CO2 gas and reduces the generation of glaze defects.

[0021] In some embodiments of the present invention, the bulk density of the lightweight ceramic brick is 1.7-1.9 g / cm³. 3 .

[0022] In some embodiments of the present invention, the maximum firing temperature is 1150-1250°C.

[0023] In some embodiments of the present invention, the firing cycle is 50-80 minutes.

[0024] In some embodiments of the present invention, a protective glaze layer is further provided on the surface of the glaze layer.

[0025] Compared with the prior art, the above-described technical solution of the present invention has at least the following technical effects or advantages:

[0026] (1) This invention uses a composite of nanoporous alumina and magnesium aluminum spinel doped with metal oxides as a radiation cooling powder, and adds it to the glaze of lightweight ceramic bricks. This not only achieves good glaze quality and brick shape, but also improves the solar reflectivity of the glaze, thus realizing a good radiation cooling effect. Among them: nanoporous alumina has a high infrared reflectivity. During the radiation cooling process, it can release heat through the atmospheric window in the form of infrared radiation, thereby achieving its own cooling effect. Magnesium aluminum spinel can be used as a raw material for preparing ceramic glaze. It will not only not have a negative impact on the glaze, but also help improve the mechanical properties of the glaze. The doped metal oxides ferric oxide, manganese dioxide, cobalt oxide, and copper oxide are all reflective raw materials. These metal oxides can emit absorbed sunlight and heat into the air at a certain wavelength, playing a blocking and reflecting role. At the same time, the doped metal oxides have a lower melting temperature, which can effectively reduce the firing temperature of the glaze. In addition, the magnesium aluminum spinel doped with metal oxides has a low coefficient of thermal expansion, which can effectively balance the difference in the coefficient of thermal expansion between nanoporous alumina and the green body.

[0027] (2) The lightweight ceramic brick prepared by the present invention has good radiation cooling function, a solar reflectivity of up to 88-94%, and good glaze quality and brick shape, with a surface flatness of ±0.3mm. Detailed Implementation

[0028] The present invention will now be described in detail with reference to embodiments to facilitate understanding of the invention by those skilled in the art. It is particularly important to note that the embodiments are merely illustrative of the invention and should not be construed as limiting the scope of protection of the invention. Non-essential improvements and adjustments made to the invention by those skilled in the art based on the above description should still fall within the scope of protection of the invention. Furthermore, all raw materials mentioned below, unless otherwise specified, are commercially available products; all process steps or preparation methods not mentioned in detail are process steps or preparation methods known to those skilled in the art.

[0029] The raw material components of the blanks used in the following examples and comparative examples, by weight, include: 45 parts feldspar, 18 parts clay, 8 parts ball clay, 5 parts talc, 5 parts bentonite, 12 parts quartz, and 0.5 parts silicon carbide.

[0030] The chemical composition of the protective glaze, by weight percentage, includes: 57% SiO2, 33% Al2O3, 0.1% Fe2O3, 0.2% TiO2, 0.4% CaO, 0.4% MgO, 2% K2O, 1% Na2O, 1% ZrO2 and 5% loss on ignition.

[0031] Example 1

[0032] A radiation-cooling glaze comprises, by weight, the following raw material components: 20 parts feldspar powder, 30 parts calcined kaolin, 25 parts quartz, 5 parts talc, 5 parts calcium carbonate, 2 parts dolomite, 3 parts borax, and 10 parts radiation-cooling powder. The radiation-cooling powder comprises 6 parts porous nano-alumina and 4 parts ferric oxide-doped magnesium aluminum spinel. The porous nano-alumina has a particle size of 20-50 nm, a pore size of 2-20 nm, and a specific surface area of ​​220 m². 2 / g; the doping amount of ferric oxide is 0.5wt%.

[0033] A method for preparing lightweight ceramic bricks includes the following steps:

[0034] (1) Weigh the raw materials according to the raw material composition of the lightweight blank, make them into powder, and then distribute, dry press and dry to obtain the lightweight blank;

[0035] (2) Weigh the raw materials for preparing the radiation-cooled glaze according to the weight ratio, and then perform wet ball milling to obtain a specific gravity of 1.8 g / cm³. 3 Radiation-cooled glaze;

[0036] (3) Weigh the raw materials according to the chemical composition of the protective glaze, and then perform wet ball milling to obtain a specific gravity of 1.9 g / cm³. 3 The protective glaze;

[0037] (4) Apply radiation-cooled glaze (glaze thickness of 0.5 mm) and protective glaze (glaze thickness of 0.3 mm) sequentially to the surface of the lightweight body prepared above to form a surface glaze layer and a protective glaze layer in sequence. After drying and firing (maximum firing temperature of 1150℃, firing cycle of 60 minutes), the lightweight ceramic brick of this embodiment is obtained.

[0038] Example 2

[0039] A radiation-cooling glaze comprises, by weight, the following raw material components: 20 parts feldspar powder, 25 parts calcined kaolin, 25 parts quartz, 5 parts talc, 5 parts calcium carbonate, 2 parts dolomite, 3 parts borax, and 15 parts radiation-cooling powder. The radiation-cooling powder comprises 10.5 parts porous nano-alumina and 4.5 parts manganese dioxide-doped magnesium aluminum spinel. The porous nano-alumina has a particle size of 20-50 nm, a pore size of 2-20 nm, and a specific surface area of ​​250 m². 2 / g; the doping amount of manganese dioxide is 0.6wt%.

[0040] A method for preparing lightweight ceramic bricks includes the following steps:

[0041] (1) Weigh the raw materials according to the raw material composition of the lightweight blank, make them into powder, and then distribute, dry press and dry to obtain the lightweight blank;

[0042] (2) Weigh the raw materials for preparing the radiation-cooled glaze according to the weight ratio, and then perform wet ball milling to obtain a specific gravity of 1.8 g / cm³. 3 Radiation-cooled glaze;

[0043] (3) Weigh the raw materials according to the chemical composition of the protective glaze, and then perform wet ball milling to obtain a specific gravity of 1.9 g / cm³. 3 The protective glaze;

[0044] (4) Apply radiation-cooled glaze (glaze thickness of 0.7 mm) and protective glaze (glaze thickness of 0.2 mm) sequentially to the surface of the lightweight body prepared above to form a surface glaze layer and a protective glaze layer in sequence. After drying and firing (maximum firing temperature of 1200℃, firing cycle of 60 minutes), the lightweight ceramic brick of this embodiment is obtained.

[0045] Example 3

[0046] A radiation-cooling glaze comprises, by weight, the following raw material components: 20 parts feldspar powder, 25 parts calcined kaolin, 25 parts quartz, 5 parts talc, 5 parts calcium carbonate, 5 parts dolomite, 5 parts borax, and 10 parts radiation-cooling powder. The radiation-cooling powder comprises 6 parts porous nano-alumina and 4 parts cobalt trioxide-doped magnesium aluminum spinel. The porous nano-alumina has a particle size of 20-50 nm, a pore size of 2-20 nm, and a specific surface area of ​​250 m². 2 / g; the cobalt trioxide doping amount is 0.6wt%.

[0047] A method for preparing lightweight ceramic bricks includes the following steps:

[0048] (1) Weigh the raw materials according to the raw material composition of the lightweight blank, make them into powder, and then distribute, dry press and dry to obtain the lightweight blank;

[0049] (2) The raw materials for preparing the radiation-cooled glaze were weighed according to the specified weight ratio and then wet-milled to obtain a specific gravity of 1.9 g / cm³. 3 Radiation-cooled glaze;

[0050] (3) Weigh the raw materials according to the chemical composition of the protective glaze, and then perform wet ball milling to obtain a specific gravity of 1.9 g / cm³. 3 The protective glaze;

[0051] (4) Apply radiation-cooled glaze (glaze thickness of 0.5 mm) and protective glaze (glaze thickness of 0.3 mm) sequentially to the surface of the lightweight body prepared above to form a surface glaze layer and a protective glaze layer in sequence. After drying and firing (maximum firing temperature of 1200℃, firing cycle of 70 minutes), the lightweight ceramic brick of this embodiment is obtained.

[0052] Example 4

[0053] A radiation-cooling glaze comprises, by weight, the following raw material components: 20 parts feldspar powder, 25 parts calcined kaolin, 20 parts quartz, 5 parts talc, 5 parts calcium carbonate, 5 parts dolomite, 5 parts borax, and 15 parts radiation-cooling powder. The radiation-cooling powder comprises 9 parts porous nano-alumina and 6 parts copper oxide-doped magnesium aluminum spinel. The porous nano-alumina has a particle size of 20-50 nm, a pore size of 2-20 nm, and a specific surface area of ​​240 m². 2 / g; the copper oxide doping amount is 0.5wt%.

[0054] A method for preparing lightweight ceramic bricks includes the following steps:

[0055] (1) Weigh the raw materials according to the raw material composition of the lightweight blank, make them into powder, and then distribute, dry press and dry to obtain the lightweight blank;

[0056] (2) Weigh the raw materials for preparing the radiation-cooled glaze according to the weight ratio, and then perform wet ball milling to obtain a specific gravity of 1.8 g / cm³. 3 Radiation-cooled glaze;

[0057] (3) Weigh the raw materials according to the chemical composition of the protective glaze, and then perform wet ball milling to obtain a specific gravity of 1.9 g / cm³. 3 The protective glaze;

[0058] (4) Apply radiation-cooled glaze (glaze thickness of 0.5 mm) and protective glaze (glaze thickness of 0.3 mm) sequentially to the surface of the lightweight body prepared above to form a surface glaze layer and a protective glaze layer in sequence. After drying and firing (maximum firing temperature of 1200℃, firing cycle of 60 minutes), the lightweight ceramic brick of this embodiment is obtained.

[0059] Comparative Example 1

[0060] The difference between Comparative Example 1 and Example 1 lies in the raw material composition of the radiation-cooling glaze. The radiation-cooling powder in the raw material composition of Comparative Example 1 is a single porous nano-alumina. The raw material composition of the radiation-cooling glaze in Comparative Example 1, by weight, includes: 20 parts feldspar powder, 30 parts calcined kaolin, 25 parts quartz, 5 parts talc, 5 parts calcium carbonate, 2 parts dolomite, 3 parts borax, and 10 parts radiation-cooling powder. The radiation-cooling powder is porous nano-alumina with a particle size of 20-50 nm, a pore size of 2-20 nm, and a specific surface area of ​​220 m². 2 / g.

[0061] The preparation method of the lightweight ceramic brick in Comparative Example 1 is the same as that in Example 1.

[0062] Comparative Example 2

[0063] The difference between Comparative Example 2 and Example 1 lies in the raw material composition of the radiation-cooling glaze. The radiation-cooling powder in Comparative Example 2 is a single type of ferric oxide-doped magnesium aluminum spinel. The raw material composition of the radiation-cooling glaze in Comparative Example 2, by weight, includes: 20 parts feldspar powder, 30 parts calcined kaolin, 25 parts quartz, 5 parts talc, 5 parts calcium carbonate, 2 parts dolomite, 3 parts borax, and 10 parts radiation-cooling powder. Specifically, the radiation-cooling powder is ferric oxide-doped magnesium aluminum spinel, and the ferric oxide doping amount is 0.5 wt%.

[0064] The preparation method of the lightweight ceramic brick in Comparative Example 2 is the same as that in Example 1.

[0065] Comparative Example 3

[0066] The only difference between Comparative Example 3 and Example 1 is the raw material composition of the radiation-cooling glaze. The radiation-cooling powder in Comparative Example 3 includes 6 parts porous nano-alumina and 4 parts zinc oxide-doped magnesium aluminum spinel. The raw material composition of Comparative Example 4, by weight, includes: 20 parts feldspar powder, 30 parts calcined kaolin, 25 parts quartz, 5 parts talc, 5 parts calcium carbonate, 2 parts dolomite, 3 parts borax, and 10 parts radiation-cooling powder. The porous nano-alumina has a particle size of 20-50 nm, a pore size of 2-20 nm, and a specific surface area of ​​200-300 m². 2 / g; the zinc oxide doping amount is 0.5wt%.

[0067] The preparation method of the lightweight ceramic brick in Comparative Example 3 is the same as that in Example 1.

[0068] Performance testing

[0069] The bulk density, solar reflectance ratio, and surface flatness of the lightweight ceramic tile samples prepared in Examples 1-4 and Comparative Examples 1-3 were tested, and their glaze quality was observed. Specifically, the solar reflectance was tested according to Part 1 of standard GJB5023.1A-2012, "Test Methods for Reflectance and Emissivity of Materials and Coatings." Reflectance refers to the proportion of solar radiation reflected by the material surface, usually expressed as a percentage. Higher reflectance means less solar energy absorbed by the surface and a lower surface temperature. Surface flatness was tested according to GB / T 4100-2015, "Ceramic Tiles," measuring the center curvature of the sample relative to the diagonal calculated from the working dimensions. The sample size was 400 × 800 mm. The test results are shown in Table 1.

[0070] Table 1:

[0071]

[0072] As shown in Table 1, the lightweight ceramic brick samples prepared in Examples 1-4 all have good radiative cooling effect, with a solar reflectivity of 88-94%; and the brick surface has high flatness; the glaze quality is good and there are no obvious defects.

[0073] Compared to Example 1, Comparative Example 1 uses a single porous nano-alumina powder for radiation cooling. The coefficient of thermal expansion of the glaze layer is excessively greater than that of the lightweight body. During the cooling process, the lightweight body is subjected to compressive stress from the glaze layer, while the glaze layer is subjected to tensile stress from the lightweight body. This causes the brick to warp upwards, resulting in severe concave deformation, making it impossible to test the solar reflectivity and flatness of the glaze surface, and causing cracking of the glaze surface.

[0074] Compared to Example 1, Comparative Example 2 used a single type of ferric oxide doped with magnesium aluminum spinel, and the coefficient of thermal expansion of the glaze layer was slightly smaller than that of the lightweight body. During the cooling process, the glaze layer was subjected to compressive stress from the lightweight body, while the lightweight body was subjected to tensile stress from the glaze layer, causing the brick to bend downwards and deform into a convex shape, making it impossible to test the solar reflectivity and flatness of the glaze surface. Simultaneously, due to the reduced alumina content, air bubbles generated in the lightweight body could not be sealed within the brick, resulting in defects such as pinholes and glaze bubbles on the glaze surface.

[0075] Compared to Example 1, Comparative Example 3 uses zinc oxide-doped magnesium aluminum spinel instead of ferric oxide-doped magnesium aluminum spinel in the radiation cooling powder. Since zinc oxide-doped magnesium aluminum spinel reduces the reflectivity in the visible light range and enhances the absorption of visible light, the solar reflectivity of the glaze surface is significantly lower than that in Example 1.

[0076] For those skilled in the art, several simple deductions or substitutions can be made without departing from the inventive concept, without requiring creative effort. Therefore, any simple improvements made to this invention by those skilled in the art based on the disclosure of this invention should be within the scope of protection of this invention. The above embodiments are preferred embodiments of this invention, and all processes similar to this invention and equivalent changes should fall within the scope of protection of this invention.

Claims

1. A radiative cooling glaze, characterized in that, The radiation cooling glaze comprises a base glaze and a radiation cooling powder, the radiation cooling powder comprises nano-porous alumina and metal oxide doped magnesium aluminate spinel, the metal oxide is at least one selected from the group consisting of ferric oxide, manganese dioxide, cobaltic oxide, and cupric oxide.

2. The radiative cooling glaze of claim 1, wherein, The doping amount of the metal oxide is 0.3-1wt%.

3. The radiative cooling glaze of claim 1, wherein, The nanoporous alumina has a particle size of 20-50 nm; and / or, the nanoporous alumina has a pore size of 2-20 nm; and / or, the nanoporous alumina has a specific surface area of 200-300 m 2 / g.

4. The radiative cooling glaze of claim 1, wherein, The mass ratio of the nano-porous alumina in the radiation cooling powder is 50-70%.

5. The radiative cooling glaze of claim 1, wherein, The mass ratio of the base glaze and the radiation cooling powder is 100:(5-20).

6. The radiative cooling glaze of claim 1, wherein, The preparation raw materials of the base glaze comprise, by weight fraction, 20-25 parts of feldspar powder, 25-30 parts of calcined kaolin, 20-25 parts of quartz, 3-5 parts of talc, 2-5 parts of calcium carbonate, 2-5 parts of dolomite, and 3-5 parts of borax.

7. A method of producing a radiative cooling glaze according to any one of claims 1-6, characterized in that, The method comprises the following steps: The base glaze and the radiation cooling powder are wet ball milled to obtain the radiation cooling glaze.

8. The method of claim 7, wherein the radiation cooling glaze is prepared by the steps of: The specific gravity of the radiation cooling glaze is 1.8-1.9 g / cm 3 .

9. A lightweight ceramic tile, characterized by, The radiation cooling glaze comprises a base glaze and a radiation cooling powder, the radiation cooling powder comprises nano-porous alumina and metal oxide doped magnesium aluminate spinel, the metal oxide is at least one selected from the group consisting of ferric oxide, manganese dioxide, cobaltic oxide, and cupric oxide.

10. The light weight ceramic tile according to claim 9, characterized in that, The highest temperature of the firing is 1150-1250℃; and / or, the firing cycle is 50-80 minutes.

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