Radiation refrigeration ceramic tile as well as preparation method and application thereof

Abstract

The invention discloses a radiative refrigeration ceramic tile as well as a preparation method and application thereof, and belongs to the technical field of building materials. Specific glaze components are selected to be glazed on a green brick, then the green brick is calcined to obtain a dicalcium silicate-based functional glaze layer with a communicated micropore structure on the surface, and then the dicalcium silicate-based functional glaze layer with the communicated micropore structure on the surface of the green brick is obtained through an in-situ carbonization reaction by utilizing the high carbonization reaction activity of dicalcium silicate. The glaze layer is converted into a firm surface layer which takes nano or micron-sized calcium carbonate crystal grains as a main component and is embedded with nano barium sulfate crystal grains; according to the surface layer, the heat ray reflection and emission characteristics of calcium carbonate crystal grains and nano barium sulfate crystal grains are utilized, and meanwhile, the micropore structure of the surface layer is utilized, so that the excellent radiation cooling function is achieved. Furthermore, the dicalcium silicate-based glaze layer and the green brick base layer are co-fired at one time and are tightly combined, so that the radiative refrigeration ceramic brick has better strength and weather resistance; therefore, the radiation refrigeration ceramic tile has a better application prospect as a building material.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of building materials, and particularly relates to a radiation refrigeration ceramic tile and a preparation method and application thereof. BACKGROUND

[0002] With the intensification of global warming trend and the continuous aggravation of urban heat island effect, the building energy consumption problem is increasingly prominent. The building cooling energy consumption in summer accounts for a considerable proportion, and the optimization of the thermal management of building outer walls becomes the key to reducing the cooling energy consumption. In recent years, the radiation refrigeration technology as a passive cooling means of buildings has attracted increasing attention and research. Radiation refrigeration can radiate heat to outer space through the atmospheric transparent window (8-13 mu m band) without external energy input, thereby realizing the cooling effect. Studies have shown that materials with high solar reflectance (> 90%) and high atmospheric window thermal emissivity (> 90%) can also achieve cooling performance better than the ambient temperature under strong sunlight in the daytime.

[0003] At present, the radiation refrigeration materials mainly focus on polymer films, metal-oxide composite layers and the like. However, the polymer film has problems such as poor weather resistance and insufficient mechanical strength, and it is difficult to meet the needs of long-term exposure to ultraviolet light, rain and temperature difference changes and other harsh environments of the building outer wall. The metal-oxide composite layer has problems such as high preparation cost and complex process. Although the traditional ceramic outer wall tile has good durability and decoration, it is limited by the composition and surface properties, and the reflectivity of sunlight is generally lower than 80%, and the mid-infrared emissivity is usually < 85%. Therefore, the high solar absorption rate and low mid-infrared emissivity characteristics of the building surface lead to heat accumulation, and the function in inhibiting the building heat load is limited, and even the heat island effect is aggravated. It is difficult to attach or combine the polymer film, metal-oxide composite layer and the like with radiation refrigeration function to the ceramic outer wall tile, and there are also key technical bottlenecks such as long-term weather resistance.

[0004] Therefore, it is necessary to develop a radiation refrigeration ceramic tile to solve the problems existing in the prior art. SUMMARY

[0005] The present application aims to provide a radiation refrigeration ceramic tile and a preparation method and application thereof. To solve the problems of poor radiation refrigeration effect, low strength and poor weather resistance of the existing radiation refrigeration materials.

[0006] In a first aspect, the present application provides a preparation method of a radiation refrigeration ceramic tile, comprising the following steps: providing a tile blank; mixing 50-65% of γ-C2S powder, 25-35% of nano-barium sulfate, 3-5% of lithium borate glass powder and 0.2-0.5% of diboron trioxide, adding water and a dispersing agent and then ball milling to obtain a slurry, adding 1-5% of an additive and 1-5% of polymethyl methacrylate microspheres to the slurry to obtain a glaze; applying the glaze on the tile blank, and then sequentially performing temperature rising calcination and temperature falling calcination to obtain a ceramic tile; performing in-situ carbonization treatment on the ceramic tile under a carbon dioxide atmosphere to obtain a radiation refrigeration ceramic tile; wherein the additive comprises at least one of an acrylic resin emulsion and carboxymethyl cellulose.

[0007] In the present application, a specific glaze component is selected to apply on the tile blank, and then a dicalcium silicate (C2S) based functional glaze layer with a connected microporous structure is obtained on the surface of the tile blank after calcination. Then, by using the high carbonation reactivity of dicalcium silicate, the glaze layer is converted and formed into a firm surface layer mainly composed of nano or micrometer calcium carbonate grains inlaid with nano barium sulfate grains through in-situ carbonization reaction. The surface layer utilizes the reflection and emission characteristics of calcium carbonate grains and nano barium sulfate grains to heat rays, and at the same time utilizes the microporous structure of the surface layer to realize excellent radiation refrigeration function. In addition, since the dicalcium silicate based glaze layer and the tile blank base layer are co-fired at one time, the combination between them is very tight, which avoids the peeling and separation phenomenon caused by temperature difference alternation or freeze-thaw cycle, so that the radiation refrigeration ceramic tile has good strength and weather resistance.

[0008] In some embodiments, in the step of obtaining the glaze, the water is added in an amount of (0.45-0.5):1 by mass ratio of the mixed material, and the dispersing agent is added in an amount of 0.1-0.2% of the mass of the mixed material; the ball milling time is 6-8h, the particle D90 particle size in the slurry is <10μm; and the particle size of the polymethyl methacrylate microspheres is 2-5μm.

[0009] In some embodiments, in the step of obtaining the glaze, the preparation of the γ-C2S powder comprises: mixing Ca(OH)2 and SiO2, adding water and ball milling, drying, calcining, and then cooling in the furnace and self-powderizing to obtain the γ-C2S powder; wherein the molar ratio of Ca(OH)2 and SiO2 is 2:1, the water is added in an amount of (1-2):1 by mass ratio of the mixed material, and the ball milling time is 4-8h; the calcining comprises: heating at a temperature rising rate of 4-6℃ / min to 1300-1400℃, and keeping the temperature for 1-3h.

[0010] In some embodiments, in the step of obtaining the ceramic tile, the glaze has a glazing thickness of 500 μm to 1 mm; the temperature increasing calcination specifically comprises: first increasing the temperature to 350-450 °C at a temperature increasing rate of 1-3 °C / min; then increasing the temperature to 800-900 °C at a temperature increasing rate of 3-6 °C / min, and maintaining the temperature for 5-10 min; finally increasing the temperature to 1200-1250 °C at a temperature increasing rate of 6-10 °C / min, and maintaining the temperature for 60-90 min.

[0011] In some embodiments, in the step of obtaining the ceramic tile, the temperature decreasing calcination specifically comprises: first decreasing the temperature to 850-950 °C at a temperature decreasing rate of 10-20 °C / min; then decreasing the temperature to 450-550 °C at a temperature decreasing rate of 40-50 °C / min; finally decreasing the temperature to room temperature at a temperature decreasing rate of 5-10 °C / min.

[0012] In some embodiments, in the step of obtaining the radiation cooling ceramic tile, before the in-situ carbonization treatment of the ceramic tile, the ceramic tile is subjected to water soaking and air drying, wherein the water soaking time is 8-12 min, the water content of the glaze layer of the air dried ceramic tile is 10-20%, the concentration of the carbon dioxide gas is >90%, the pressure is 0.2-0.3 MPa, and the in-situ carbonization treatment time is 6-12 h.

[0013] In some embodiments, in the step of providing the green tile, the preparation of the green tile comprises: mixing 35-45% kaolin, 5-10% clay, 20-30% feldspar, 15-25% quartz, and 0-5% alumina by mass percentage, adding water and a dispersant, and then ball milling to obtain a slurry; spray drying the slurry to obtain a spherical particle powder; and shaping and drying the spherical particle powder to obtain the green tile.

[0014] In some embodiments, in the step of obtaining the slurry, the water is added in an amount of (0.32-0.35):1 by mass ratio of the mixed material, and the dispersant is added in an amount of 0.2-0.22% of the mass of the mixed material; the ball milling time is 8-10 h, the particle D50 size in the slurry is 2-4 μm, and the mesh size of the screen is 150-300 mesh; in the step of obtaining the spherical particle powder, the water content of the spherical particle powder is 6-8%, and the particle size is 50-150 μm; and in the step of obtaining the green tile, the shaping pressure is 25-30 MPa, and the water content of the green tile is <0.5%.

[0015] In a second aspect, the present application provides a radiation cooling ceramic tile prepared by any of the above preparation methods.

[0016] In a third aspect, the present application provides the use of the above radiation cooling ceramic tile in building materials.

[0017] The beneficial effects of the present application are: different from the prior art, the present application glazes the brick body by selecting specific glaze components, then obtains the dicalcium silicate (C2S) based functional glaze layer with interconnected microporous structure on the surface of the brick body after calcination, then utilizes the high carbonization reaction activity of dicalcium silicate, and through in-situ carbonization reaction, the glaze layer is transformed into a firm surface layer mainly composed of nano or micrometer calcium carbonate grains, and inlaid with nano barium sulfate grains; the surface layer utilizes the reflection and emission characteristics of the calcium carbonate grains and nano barium sulfate grains to heat rays, and at the same time utilizes the microporous structure of the surface layer, to realize excellent radiation refrigeration function. In addition, since the dicalcium silicate based glaze layer and the brick body base layer are co-fired at one time, the combination between the two is very tight, and the phenomenon of peeling and separation caused by temperature difference alternation or freeze-thaw cycle is avoided, so that the radiation refrigeration ceramic brick has good strength and weather resistance; therefore, the radiation refrigeration ceramic brick has good application prospect as a building material. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The preparation method flow chart of the radiation refrigeration ceramic brick in the present application is shown in the figure; Figure 2 The XRD pattern of the carbonized ceramic brick radiation refrigeration glaze layer obtained in step S4 of Example 1 of the present application is shown in the figure; Figure 3 The XRD pattern of the carbonized ceramic brick radiation refrigeration glaze layer obtained in step S5 of Example 1 of the present application is shown in the figure. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0020] The experimental methods not specified in the embodiments are usually carried out according to the conventional conditions and the conditions described in the manual, or according to the conditions suggested by the manufacturers, and the general equipment, materials, reagents, etc. used are commercially available, unless otherwise specified.

[0021] In the present application, the preparation of γ-C2S powder includes: mixing Ca(OH)2 and SiO2 according to a molar ratio of 2:1, adding into a ball mill, ball milling for 6 h with a water-solid ratio of 1.5, drying, then heating to 1350℃ at a heating rate of 5℃ / min, keeping for 2 h, then cooling with the furnace, and then obtaining γ-C2S powder through self-pulverization.

[0022] The particle size of the polymethyl methacrylate microspheres is 2-5 μm.

[0023] At present, the existing radiation refrigeration material has problems of poor radiation refrigeration effect, low strength and poor weather resistance.

[0024] In order to solve the problems of poor radiation refrigeration effect, low strength and poor weather resistance of the existing radiation refrigeration material, the present application provides a radiation refrigeration ceramic tile and a preparation method and application thereof.

[0025] In a first aspect, the present application provides a preparation method of a radiation refrigeration ceramic tile, comprising the following steps: providing a tile blank; mixing 50-65% of γ-C2S powder, 25-35% of nano-barium sulfate, 3-5% of lithium borate glass powder and 0.2-0.5% of diboron trioxide, adding water and a dispersing agent and then performing ball milling to obtain a slurry, adding 1-5% of an additive and 1-5% of polymethyl methacrylate microspheres to the slurry to obtain a glaze; applying the glaze on the tile blank, and then sequentially performing temperature rising calcination and temperature reduction calcination to obtain a ceramic tile; performing in-situ carbonization treatment on the ceramic tile under a carbon dioxide atmosphere to obtain a radiation refrigeration ceramic tile; wherein the additive comprises at least one of an acrylic resin emulsion and carboxymethyl cellulose.

[0026] In the preparation method of the radiation refrigeration ceramic tile provided by the present application, a specific glaze component is selected to be applied on the tile blank, and then a dicalcium silicate (C2S) based functional glaze layer with a connected microporous structure is obtained on the surface of the tile blank after calcination, then the high carbonization reactivity of dicalcium silicate is utilized to convert the glaze layer into a firm surface layer mainly composed of nano or micrometer level calcium carbonate grains inlaid with nano barium sulfate grains through in-situ carbonization reaction; the surface layer utilizes the reflection and emission characteristics of calcium carbonate grains and nano barium sulfate grains to heat rays, and simultaneously utilizes the microporous structure of the surface layer to realize excellent radiation refrigeration function. In addition, since the dicalcium silicate based glaze layer and the tile blank base layer are co-fired at one time, the combination between them is very tight, which avoids the peeling and separation phenomenon caused by temperature difference alternation or freeze-thaw cycle, so that the radiation refrigeration ceramic tile has good strength and weather resistance.

[0027] Further, in the present application, the polymethyl methacrylate microspheres are added in the glaze, which plays a role of pore-forming agent in the glaze firing process, is conducive to the formation of CO2 gas channels in the in-situ carbonization process, and significantly improves the carbonization degree of the dicalcium silicate glaze layer, at the same time, the microporous cavities formed by the melting of the polymethyl methacrylate microspheres in the firing process help to relieve the volume expansion stress and water migration stress generated in the water freezing process, thereby improving the freeze-thaw cycle resistance of the glaze surface; the lithium borate glass powder is added, which promotes the uniform melting of the glaze components in the glaze firing process and improves the bonding force between the glaze layer and the base layer; the additive is added, which is conducive to improving the viscosity and adhesion of the glaze, and also plays a role of pore-forming agent in the glaze firing process.

[0028] Further, the preparation method provided by the present application is simple and feasible, the raw materials are cheap and easy to obtain, and the present application has the advantage of low cost, thus being suitable for industrial large-scale production application.

[0029] In some embodiments, in the step of obtaining the glaze, the water is added in an amount of (0.45-0.5):1 by mass ratio of the mixed material, and the dispersant is added in an amount of 0.1-0.2% by mass ratio of the mixed material; the ball milling time is 6-8h, the particle D90 size in the slurry is <10μm; the polymethyl methacrylate microspheres have a particle size of 2-5μm, and the glaze has a solid content of 35-50%.

[0030] In the present application, the raw materials are mixed uniformly and have a large specific surface area by ball milling the glaze, which is beneficial to uniform coating of the glaze on the brick body.

[0031] It can be understood that the type of dispersant can be routinely adjusted according to actual needs, as long as it is beneficial to efficient ball milling. For example, in the present application, the dispersant is preferably a polycarboxylate dispersant.

[0032] In some embodiments, in the step of obtaining the glaze, the preparation of the γ-C2S powder comprises: mixing Ca(OH)2 and SiO2, adding water and ball milling, drying, calcining, then cooling with the furnace, and obtaining the γ-C2S powder by self-pulverization; wherein the molar ratio of Ca(OH)2 and SiO2 is 2:1, the water is added in an amount of (1-2):1 by mass ratio of the mixed material, and the ball milling time is 4-8h; the calcining comprises: heating at a heating rate of 4-6℃ / min to 1300-1400℃, and maintaining for 1-3h.

[0033] In the present application, by controlling the preparation process parameters of the γ-C2S powder within a specific range, a γ-C2S powder with good performance can be prepared.

[0034] In some embodiments, in the step of obtaining the ceramic tile, the glaze application thickness of the glaze is 500μm-1mm; the heating and calcining specifically comprises: first heating at a heating rate of 1-3℃ / min to 350-450℃; then heating at a heating rate of 3-6℃ / min to 800-900℃ and maintaining for 5-10min; finally heating at a heating rate of 6-10℃ / min to 1200-1250℃ and maintaining for 60-90min.

[0035] In the present application, by calcining at a temperature of 800-900℃, the additives and polymethyl methacrylate microspheres in the glaze can be decomposed, and a large number of interconnected micropores can be formed in the glaze layer; by calcining at a temperature of 1200-1250℃, the glaze can be fully melted to form a glaze layer and form β-C2S and a small amount of γ-C2S minerals.

[0036] In some embodiments, in the step of obtaining the ceramic tile, the cooling calcination specifically comprises: firstly cooling to 850-950 DEG C at a cooling rate of 10-20 DEG C / min, then cooling to 450-550 DEG C at a cooling rate of 40-50 DEG C / min, and finally cooling to room temperature at a cooling rate of 5-10 DEG C / min.

[0037] In the present application, by performing the segmented cooling, the C2S crystals in the glaze layer mainly exist in the form of beta-C2S crystals, avoiding the self-pulverization phenomenon caused by the large amount of conversion into gamma-C2S crystals in the conventional slow cooling process, and causing the quality of the glaze layer to decrease.

[0038] In some embodiments, in the step of obtaining the radiation refrigeration ceramic tile, before the in-situ carbonization treatment is performed on the ceramic tile, the ceramic tile is further subjected to a water soaking and air drying process, wherein the water soaking time is 8-12 min, the water content of the glaze layer of the air dried ceramic tile is 10-20%, the concentration of the carbon dioxide gas is >90%, the pressure is 0.2-0.3 MPa, and the in-situ carbonization treatment time is 6-12 h.

[0039] In the present application, by controlling the process parameters of the in-situ carbonization within a specific range, the in-situ carbonization reaction can be completely performed, the glaze layer is transformed into a firm surface layer mainly composed of nano or micron calcium carbonate crystals and embedded with nano barium sulfate crystals, and the radiation refrigeration effect of the ceramic tile is significantly improved.

[0040] In some embodiments, in the step of providing the green tile, the preparation of the green tile comprises: mixing 35-45% kaolin, 5-10% clay, 20-30% feldspar, 15-25% quartz and 0-5% alumina by mass percentage, adding water and a dispersant, and then performing ball milling, screening, and obtaining a slurry; performing spray drying on the slurry to obtain spherical particle powder; and performing shaping and drying on the spherical particle powder to obtain the green tile.

[0041] In the present application, by selecting specific components of the green tile, the green tile with good performance is obtained after ball milling, drying and shaping.

[0042] In some embodiments, in the step of obtaining the slurry, the water addition amount is (0.32-0.35):1 of the mass of the mixed material, the dispersant addition amount is 0.2-0.22% of the mass of the mixed material, the ball milling time is 8-10 h, the particle D50 particle size in the slurry is 2-4 μm, and the screen mesh aperture is 150-300 meshes; in the step of obtaining the spherical particle powder, the water content of the spherical particle powder is 6-8%, and the particle size is 50-150 μm; and in the step of obtaining the green tile, the shaping pressure is 25-30 MPa, and the water content of the green tile is <0.5%.

[0043] In the present application, by controlling the parameters in the brick preparation process within a specific range, the performance of the brick can be further improved.

[0044] In a second aspect, the present application provides a radiation cooling ceramic brick prepared by any of the above preparation methods.

[0045] The radiation cooling ceramic brick provided by the present application has excellent radiation cooling effect, as well as good strength and weather resistance.

[0046] In a third aspect, the present application provides the use of the above radiation cooling ceramic brick in building materials.

[0047] Some specific examples are listed below, it should be noted that the examples described below are exemplary, only for explaining the present application, and cannot be understood as limiting the present application.

[0048] Please refer to Figure 1 which is a preparation method flow chart of the radiation cooling ceramic brick in the present application. Specifically, the preparation method of the radiation cooling ceramic brick comprises the following steps: providing a brick; mixing 50-65% of γ-C2S powder, 25-35% of nano-barium sulfate, 3-5% of lithium borate glass powder and 0.2-0.5% of diboron trioxide by mass percentage, adding water and a dispersing agent, and then ball milling to obtain a slurry, adding 1-5% of an additive and 1-5% of polymethyl methacrylate microspheres to the slurry to obtain a glaze; applying the glaze to the brick, and then sequentially performing temperature rising calcination and temperature reduction calcination to obtain a ceramic brick; and performing in-situ carbonization treatment on the ceramic brick under a carbon dioxide atmosphere to obtain a radiation cooling ceramic brick.

[0049] Example 1 A preparation method of a radiation cooling ceramic brick comprises the following steps: S1, preparation of a brick: S11, by mass percentage, 35% of kaolin, 10% of clay, 30% of feldspar and 25% of quartz are mixed, then added into a ball mill, ball milled for 8h after adding water and 0.2% of polycarboxylate dispersant based on the mass of the mixed material at a water-solid ratio of 0.35 (at this time, the particle D50 particle size in the slurry is 4μm), sieved through a 200 mesh screen to remove coarse particles and impurities, and a slurry is obtained; S12, the slurry obtained in step S11 is spray dried to obtain a spherical particle powder with a water content of 6.7% and a particle size of 65μm; S13, the spherical particle powder obtained in step S12 is placed in a hydraulic machine and formed under a pressure of 25MPa, and then slowly dried in a drying kiln to a water content of 0.46% to obtain a brick.

[0050] S2, Preparation of glaze: S21, 55.5% of γ-C2S powder, 35% of nano-barium sulfate, 5% of lithium borate glass powder, and 0.5% of diboron trioxide were weighed in percentage by mass, mixed, and then added into a ball mill, 0.45 of water and 0.2% of polycarboxylate dispersant based on the mass of the mixed material were added, and then ball-milled for 7h (at this time, the particle D90 particle size in the slurry was 7μm), to obtain a slurry; S22, 1% of carboxymethyl cellulose and 3% of polymethyl methacrylate microspheres were added into the slurry obtained in step S21 and stirred uniformly, and the solid content of the slurry was adjusted and controlled to be 35%, to obtain a glaze.

[0051] S3, Glazing: S31, the glaze obtained in step S2 was attached to the surface of the green brick obtained in step S1 in a spraying or dipping manner, and the glazing thickness was controlled to be 650μm; S32, the glazed green brick was dried at a low temperature of 60℃ for 4h.

[0052] S4, Firing of ceramic tile: S41, the glazed green brick obtained in step S3 was put into a kiln for firing, first, temperature rising calcination was performed, specifically, the temperature was raised to 400℃ at a temperature rising rate of 1℃ / min; then the temperature was raised to 850℃ at a temperature rising rate of 5℃ / min, and kept for 7min; finally, the temperature was raised to 1250℃ at a temperature rising rate of 8℃ / min, and kept for 60min; S42, then, temperature dropping calcination was performed, specifically, the temperature was dropped to 900℃ at a temperature dropping rate of 10℃ / min, then the temperature was dropped to 500℃ at a temperature dropping rate of 45℃ / min, and finally the temperature was dropped to room temperature at a temperature dropping rate of 10℃ / min, to obtain a ceramic tile.

[0053] S5, In-situ carbonization of ceramic tile: S51, the ceramic tile obtained in step S4 was placed in a vacuum container and soaked in water for 10min, and then taken out and air-dried until the surface was dry (at this time, the water content in the glaze layer was 12%); S52, the air-dried ceramic tile obtained in step S51 was arranged in parallel at an interval of 1cm and placed in a carbonization kettle, and CO2 gas with a concentration of 99% and a gas pressure of 0.3MPa was introduced for rapid carbonization for 6h; S53, after natural drying of the carbonized ceramic tile obtained in step S52, a radiation refrigeration ceramic tile was obtained.

[0054] Example 2 A preparation method of a radiation refrigeration ceramic tile, comprising the following steps: S1, Preparation of green brick: S11, 45% kaolin, 5% clay, 25% feldspar, 20% quartz, and 5% alumina are mixed in percentage by mass, and then added into a ball mill, water and 0.22% of the mass of the mixed material of polycarboxylate dispersant are added according to the water-solid ratio of 0.32, and then ball milled for 9h (at this time, the particle D50 size in the slurry is 3μm), after sieving through a 200 mesh screen, coarse particles and impurities are removed, and a slurry is obtained; S12, the slurry obtained in step S11 is spray dried to obtain spherical particle powder with a moisture content of 7.1% and a particle size of 120μm; S13, the spherical particle powder obtained in step S12 is placed in a hydraulic machine to form under a pressure of 30MPa, and then slowly dried in a drying kiln to a moisture content of 0.38% to obtain a green brick.

[0055] S2, preparation of glaze: S21, 65% γ-C2S powder, 25% nano-barium sulfate, 3.7% lithium borate glass powder, and 0.3% diboron trioxide are mixed in percentage by mass, and then added into a ball mill, water and 0.18% of the mass of the mixed material of polycarboxylate dispersant are added according to the water-solid ratio of 0.48, and then ball milled for 6h (at this time, the particle D90 size in the slurry is 9μm), and a slurry is obtained; S22, 2% of the slurry obtained in step S21 is added with acrylic resin emulsion, 4% of polymethyl methacrylate microspheres, and stirred uniformly, and the solid content of the slurry is adjusted and controlled to 40% to obtain a glaze.

[0056] S3, glazing: S31, the glaze obtained in step S2 is attached to the surface of the green brick obtained in step S1 by spraying or dipping, and the glazing thickness is controlled to be 1000μm; S32, the glazed green brick is dried at a low temperature of 80℃ for 3h.

[0057] S4, firing of ceramic tile: S41, the glazed green brick obtained in step S3 is fired into a kiln, first, temperature rising calcination is performed, specifically, first, the temperature is raised to 400℃ at a temperature rising rate of 2℃ / min; then the temperature is raised to 850℃ at a temperature rising rate of 3℃ / min, and kept for 5min; finally, the temperature is raised to 1200℃ at a temperature rising rate of 6℃ / min, and kept for 90min; S42, then, temperature reduction calcination is performed, specifically, first, the temperature is reduced to 900℃ at a temperature reduction rate of 20℃ / min, then the temperature is reduced to 500℃ at a temperature reduction rate of 50℃ / min, and finally, the temperature is reduced to room temperature at a temperature reduction rate of 8℃ / min, to obtain a ceramic tile.

[0058] S5, in-situ carbonization of ceramic tile: S51, the ceramic tile obtained in step S4 is placed in a vacuum container and soaked for 10 min, and after being fished out, it is dried until the surface is dry (at this time, the water content in the glaze layer is 20%); S52, the dried ceramic tile obtained in step S51 is arranged in parallel at an interval of 2 cm and placed in a carbonization pot, and 99% CO2 gas with a gas pressure of 0.25 MPa is introduced for rapid carbonization for 9 h; S53, after the ceramic tile obtained in step S52 is naturally dried after carbonization, a radiation refrigeration ceramic tile is obtained.

[0059] Example 3 A preparation method of a radiation refrigeration ceramic tile, comprising the following steps: S1, preparation of a green body: S11, 43% kaolin, 9% clay, 23% feldspar, 22% quartz and 3% alumina are weighed in percentage by mass, mixed and then added to a ball mill, water is added at a water-solid ratio of 0.33, and 0.21% of a polycarboxylate dispersant based on the mass of the mixed material is added, and then ball milled for 10 h (at this time, the particle D50 size in the slurry is 2 μm), and then sieved through a 200 mesh screen to remove coarse particles and impurities, to obtain a slurry; S12, the slurry obtained in step S11 is spray dried to obtain spherical particle powder with a water content of 6.2% and a particle size of 92 μm; S13, the spherical particle powder obtained in step S12 is placed in a hydraulic machine and formed under a pressure of 27.5 MPa, and then slowly dried in a drying kiln to a water content of 0.26% to obtain a green body.

[0060] S2, preparation of a glaze: S21, 60% γ-C2S powder, 30% nano-barium sulfate, 4.5% lithium borate glass powder and 0.2% diboron trioxide are weighed in percentage by mass, mixed and then added to a ball mill, water is added at a water-solid ratio of 0.5, and 0.1% of a polycarboxylate dispersant based on the mass of the mixed material is added, and then ball milled for 8 h (at this time, the particle D90 size in the slurry is 5 μm) to obtain a slurry; S22, 4% acrylic resin emulsion and 1.3% polymethyl methacrylate microspheres are added to the slurry obtained in step S21 and stirred uniformly, and the solid content of the slurry is adjusted and controlled to 50% to obtain a glaze.

[0061] S3, glazing: S31, the glaze obtained in step S2 is attached to the surface of the green body obtained in step S1 by spraying or dipping, and the glazing thickness is controlled to be 800 μm; S32, the glazed green body is dried at a low temperature of 70°C for 3.5 h.

[0062] S4, firing of the ceramic tile: S41, the glazing tile obtained in step S3 is fired into a kiln, first, temperature rising calcination is performed, specifically, first, temperature is raised to 400℃ at a temperature rising rate of 3℃ / min; then, temperature is raised to 850℃ at a temperature rising rate of 4.5℃ / min, and kept for 10min; finally, temperature is raised to 1230℃ at a temperature rising rate of 10℃ / min, and kept for 75min; S42, then, temperature dropping calcination is performed, specifically, first, temperature is dropped to 900℃ at a temperature dropping rate of 15℃ / min, then, temperature is dropped to 500℃ at a temperature dropping rate of 40℃ / min, finally, temperature is dropped to room temperature at a temperature dropping rate of 5℃ / min, to obtain the ceramic tile.

[0063] S5, in-situ carbonization of the ceramic tile: S51, the ceramic tile obtained in step S4 is placed in a vacuum container and soaked for 10min, and after being taken out, it is air-dried until the surface is dry (at this time, the water content in the glaze layer is 15%); S52, the air-dried ceramic tile obtained in step S51 is arranged in parallel at an interval of 1.5cm and placed in a carbonization kettle, and CO2 gas with a concentration of 99% and a gas pressure of 0.2MPa is introduced for rapid carbonization for 12h; S53, after the carbonized ceramic tile obtained in step S52 is naturally dried, a radiation refrigeration ceramic tile is obtained.

[0064] Comparative Example 1 In this comparative example, the preparation method of the radiation refrigeration ceramic tile is basically the same as that in Example 1, except that step S5 is not performed.

[0065] Comparative Example 2 In this comparative example, the preparation method of the radiation refrigeration ceramic tile is basically the same as that in Example 1, except that in step S2, no nano-barium sulfate is added, and an equal amount of γ-C2S powder is used instead.

[0066] Comparative Example 3 In this comparative example, the preparation method of the radiation refrigeration ceramic tile is basically the same as that in Example 1, except that in step S2, no polymethyl methacrylate microspheres are added, and an equal amount of γ-C2S powder is used instead.

[0067] Comparative Example 4 In this comparative example, the preparation method of the radiation refrigeration ceramic tile is basically the same as that in Example 1, except that in step S2, no lithium borate glass powder is added, and an equal amount of γ-C2S powder is used instead.

[0068] Performance test Exemplarily, the carbonized pre-ceramic tile radiation refrigeration glaze layer obtained in step S4 of embodiment 1 and the carbonized post-ceramic tile radiation refrigeration glaze layer obtained in step S5 were subjected to XRD detection, and the results are shown in Figure 2 and 3 , respectively.

[0069] As can be seen from Figure 2 , after calcination of the ceramic tile, the C2S crystals in the glaze layer mainly exist in the form of β-C2S crystals and contain a small amount of γ-C2S minerals; further, as can be seen from Figure 3 , after in-situ carbonization of the calcined ceramic tile, the glaze layer is converted into a main component of calcium carbonate crystals and barium sulfate crystals.

[0070] Further, the optical properties of the radiation refrigeration ceramic tiles prepared in embodiments 1-3 and comparative examples 1-4 were tested, and the results are shown in Table 1: Table 1 Test results of optical properties of radiation refrigeration ceramic tiles

[0071] As can be seen from the data in Table 1, the radiation refrigeration ceramic tiles prepared in embodiments 1-3 have good radiation refrigeration effect. In comparative example 1, no in-situ carbonization is performed, and it is found that the solar reflectance and atmospheric window thermal emissivity significantly decrease, indicating that the in-situ carbonization process helps to improve the radiation refrigeration performance of the glaze surface, and the reason is that the carbonated calcium carbonate microcrystalline phase has better solar reflectance and infrared emissivity than the dicalcium silicate mineral before carbonization. In comparative example 2, no nano-barium sulfate is added, and it is found that the solar reflectance and atmospheric window thermal emissivity significantly decrease, indicating that the nano-barium sulfate has an important influence on the radiation refrigeration effect of the ceramic tile, and the absence of this component will significantly reduce the radiation refrigeration effect of the glaze surface. In comparative examples 3 and 4, no polymethyl methacrylate microspheres or lithium borate glass powder is added, and it is found that the solar reflectance and atmospheric window thermal emissivity have decreased to some extent, indicating that both the polymethyl methacrylate microspheres and the lithium borate glass powder can improve the radiation refrigeration effect of the ceramic tile.

[0072] Further, the glaze crack resistance and frost resistance of the radiation refrigeration ceramic tiles prepared in embodiments 1-3 and comparative examples 3-4 were tested, wherein the glaze crack resistance was tested according to the method in GB / T 3810.11, and the frost resistance was tested according to the method in GB / T 3810.12, specifically, after 100 cycles according to the specified method, whether cracks appeared on the glaze surface and the body was observed; the ceramic tile was then placed in the outdoor natural environment, and after 1 year, the test was repeated, and the results are shown in Table 2: Table 2 Test results of glaze crack resistance and frost resistance of radiation refrigeration ceramic tiles

[0073] As can be seen from Table 2, the radiation refrigeration ceramic tiles prepared in Examples 1-3 have good strength and weather resistance. In Comparative Example 3, no polymethyl methacrylate microspheres are added, and it is found that cracks appear on the glaze, which shows that the micro-porous cavities formed by the melting of the added polymethyl methacrylate microspheres during the firing process help to relieve the volume expansion stress and water migration stress generated during the freezing process of water, thereby improving the freeze-thaw cycle performance of the glaze. In Comparative Example 4, no lithium borate glass powder is added, and it is found that cracks appear on the glaze, which shows that the lithium borate glass powder plays an important role in promoting the uniform melting of the glaze, improving the bonding force between the glaze layer and the body layer, and improving the integrity of the glaze.

[0074] In conclusion, the radiation refrigeration ceramic tile with good radiation refrigeration, good bonding strength and good weather resistance is prepared by optimizing the glaze components and using a specific preparation process.

[0075] It should be noted that each of the above embodiments belongs to the same inventive concept, and the description of each embodiment has its own emphasis. If not fully described in individual embodiments, reference can be made to the description in other embodiments.

[0076] The above-described embodiments only express the implementation of the present application, and the description is more specific and detailed, but it should not be understood as limiting the scope of the patent. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the scope of protection of the present application. Therefore, the scope of protection of the present application should be subject to the appended claims.

Claims

1. A method for producing a radiation-cooled ceramic tile, characterized by, The method comprises the following steps: providing a brick body; mixing 50-65% of γ-C2S powder, 25-35% of nano-barium sulfate, 3-5% of lithium borate glass powder and 0.2-0.5% of diboron trioxide in percentage by mass, adding water and a dispersant and then performing ball milling to obtain a slurry, adding 1-5% of an additive and 1-5% of polymethyl methacrylate microspheres to the slurry to obtain a glaze; applying the glaze on the brick body, and then sequentially performing temperature rising calcination and temperature dropping calcination to obtain a ceramic tile; performing in-situ carbonization treatment on the ceramic tile in a carbon dioxide atmosphere to obtain a radiation refrigeration ceramic tile; wherein the additive comprises at least one of an acrylic resin emulsion and carboxymethyl cellulose.

2. The production method according to claim 1, characterized by, In the step of obtaining the glaze, the water is added in an amount of (0.45-0.5):1 by mass ratio of the mixed material, and the dispersant is added in an amount of 0.1-0.2% of the mass of the mixed material; the ball milling time is 6-8h, and the particle D90 size in the slurry is less than 10μm; the polymethyl methacrylate microspheres have a particle size of 2-5μm.

3. The production method according to claim 1, characterized by, In the step of obtaining the glaze, the preparation of the γ-C2S powder comprises: mixing Ca(OH)2 and SiO2, adding water and performing ball milling, drying, calcination, furnace cooling, and then self-powdering to obtain the γ-C2S powder; wherein the molar ratio of the Ca(OH)2 to the SiO2 is 2:1, the water is added in an amount of (1-2):1 by mass ratio of the mixed material, and the ball milling time is 4-8h; the calcination comprises: rising the temperature to 1300-1400℃ at a temperature rising rate of 4-6℃ / min, and maintaining the temperature for 1-3h.

4. The method of claim 1, wherein, In the step of obtaining the ceramic tile, the glaze is applied in a thickness of 500μm-1mm; the temperature rising calcination specifically comprises: first rising the temperature to 350-450℃ at a temperature rising rate of 1-3℃ / min; then rising the temperature to 800-900℃ at a temperature rising rate of 3-6℃ / min and maintaining the temperature for 5-10min; and finally rising the temperature to 1200-1250℃ at a temperature rising rate of 6-10℃ / min and maintaining the temperature for 60-90min.

5. The preparation method according to claim 1, characterized in that, In the step of obtaining the ceramic tile, the temperature dropping calcination specifically comprises: first dropping the temperature to 850-950℃ at a temperature dropping rate of 10-20℃ / min, then dropping the temperature to 450-550℃ at a temperature dropping rate of 40-50℃ / min, and finally dropping the temperature to room temperature at a temperature dropping rate of 5-10℃ / min.

6. The method of claim 1, wherein, In the step of obtaining the radiation refrigeration ceramic tile, before the in-situ carbonization treatment is performed on the ceramic tile, the ceramic tile is further subjected to water soaking and air drying, wherein the water soaking time is 8-12min, and the water content of the glaze layer of the air dried ceramic tile is 10-20%; the carbon dioxide gas has a concentration of >90% and a pressure of 0.2-0.3MPa; the in-situ carbonization treatment time is 6-12h.

7. The preparation method according to claim 1, characterized in that, In the step of providing the brick body, the preparation of the brick body comprises: Mixing 35-45% kaolin, 5-10% clay, 20-30% feldspar, 15-25% quartz and 0-5% alumina in percentage of mass, adding water and dispersant, ball milling, screening, and then obtaining slurry; Spray drying the slurry to obtain spherical granular powder; Forming and drying the spherical granular powder to obtain green brick.

8. The production method according to claim 7, characterized by, In the step of obtaining slurry, the water adding amount is (0.32-0.35):1 of the mass of the mixed material, and the dispersant adding amount is 0.2-0.22% of the mass of the mixed material; the ball milling time is 8-10h, the particle D50 size in the slurry is 2-4μm, and the screen mesh aperture is 150-300 mesh; in the step of obtaining spherical granular powder, the water content of the spherical granular powder is 6-8%, and the particle size is 50-150μm; in the step of obtaining green brick, the forming pressure is 25-30MPa, and the water content of the green brick is <0.5%.

9. A radiative cooling ceramic tile, characterized in that, Prepared by the preparation method of any one of claims 1-8.

10. Use of the radiation-cooled ceramic brick of claim 9 in building materials.

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