Rare earth near-infrared reflective ceramic material, preparation method and application thereof

Abstract

The application belongs to the field of rare earth secondary resource recycling, and particularly relates to a rare earth near-infrared reflective ceramic material, a preparation method and application thereof. The rare earth near-infrared reflective ceramic material comprises 0-1 parts of rare earth polishing powder waste, 0-1 parts of fluorescent powder waste and 0-0.3 parts of permanent magnet waste. The application can realize effective comprehensive utilization of rare earth secondary resources, and obtain a cold pigment with high near-infrared reflectivity and bright color.

Description

Technical Field

[0001] This invention belongs to the field of rare earth secondary resource recycling, and particularly relates to a rare earth near-infrared reflective ceramic material, its preparation method and application. Background Technology

[0002] Rare earth elements are a vital non-renewable strategic resource, widely used in the development of high-tech industries, especially new materials. With the rapid development of industries such as new energy, the demand for rare earth elements is constantly increasing, leading to a corresponding year-on-year increase in rare earth waste and residue. Improper disposal of rare earth waste not only wastes resources but also pollutes the environment. Therefore, how to effectively utilize rare earth waste and residue is a key issue of concern in this field.

[0003] Currently, the recycling of rare earth waste and residue mainly adopts physical, chemical, and biological methods. However, the current recycling processes for rare earth waste and residue have problems such as complicated recycling steps, high process costs, crude production processes, large consumption of chemical raw materials, low product added value, and secondary environmental pollution caused by the generation of waste.

[0004] Utilizing the high added value of rare earth waste residues can help alleviate the increasingly serious energy situation and environmental problems. Meanwhile, the surfaces of high-temperature heat storage bodies such as buildings and roads are mostly made of low-reflection materials. These materials can absorb short-wave solar radiation, causing it to be reflected and captured again by buildings and streets. The obstruction of the sky by buildings causes heat to be intercepted by the surfaces of these obstacles and absorbed or radiated back into the city, which is also one of the main factors contributing to the "urban heat island effect."

[0005] Cold pigments, with their excellent high near-infrared reflectance and ability to block the transmission of solar energy, have become an important measure to mitigate the "urban heat island effect" and have great application value in building energy conservation. Most high near-infrared reflectance coatings are mainly white and light-colored. Although they can reflect sunlight well, the monotonous colors are difficult to meet people's aesthetic needs. Pigments are the main components that give paint color, and the near-infrared reflectance of pigments directly affects the heat insulation performance of the coating. Most existing colored pigments contain heavy metals such as Pd, Cd, Co, and Cr, which not only have low near-infrared reflectance but also easily cause environmental pollution.

[0006] In recent years, rare earth elements have been used as substitutes for toxic heavy metals due to their good chemical stability, thermal stability, low toxicity and color diversity. They have been studied and used in many pigments. However, when using rare earth elements to prepare pigments, it is usually necessary to use rare earth elements with well-defined composition and content as raw materials, which leads to high costs. Summary of the Invention

[0007] To address the shortcomings of existing technologies, a rare-earth near-infrared reflective ceramic material, its preparation method, and its applications are proposed, enabling the effective and comprehensive utilization of rare-earth secondary resources.

[0008] A brightly colored cold pigment with high near-infrared reflectance was obtained. To achieve the above objective, the technical solution of this invention is as follows:

[0009] In a first aspect, the present invention provides a rare earth near-infrared reflective ceramic material, wherein, by mass, the rare earth near-infrared reflective ceramic material comprises 0-1 parts of rare earth polishing powder waste, 0-1 parts of phosphor waste and 0-0.3 parts of permanent magnet waste.

[0010] According to an embodiment of the present invention, the rare earth near-infrared reflective ceramic material comprises, by weight, 0.1 to 1 part of rare earth polishing powder waste, 0.1 to 1 part of phosphor waste and 0.1 to 0.3 parts of permanent magnet waste.

[0011] According to an embodiment of the present invention, the rare earth near-infrared reflective ceramic material comprises, by weight, 0.2 to 1 part of rare earth polishing powder waste, 0.3 to 1 part of phosphor waste and 0.1 to 0.2 parts of permanent magnet waste.

[0012] According to an embodiment of the present invention, the rare earth near-infrared reflective ceramic material comprises, by weight, 0.3 to 1 part of rare earth polishing powder waste, 0.5 to 1 part of phosphor waste and 0.1 to 0.2 parts of permanent magnet waste.

[0013] According to an embodiment of the present invention, the rare earth near-infrared reflective ceramic material comprises 0.1 to 1 part of rare earth polishing powder waste and 0.1 to 1 part of phosphor waste by weight, for example, the mass ratio of the rare earth polishing powder waste to the phosphor waste is 10:1, 5:1, 3:1, 1:1, 1:10, 1:5, or 1:2.

[0014] According to an embodiment of the present invention, the rare earth near-infrared reflective ceramic material comprises, by weight, 0.1 to 1 part of rare earth polishing powder waste and 0.1 to 0.3 parts of permanent magnet waste. Preferably, the rare earth near-infrared reflective ceramic material comprises 0.5 to 1 part of rare earth polishing powder waste and 0.1 to 0.2 parts of permanent magnet waste. For example, the mass ratio of the rare earth polishing powder waste to the permanent magnet waste is 10:1, 5:1, 3:1, or 1:1.

[0015] According to an embodiment of the present invention, the rare earth near-infrared reflective ceramic material package contains 0.1 to 1 parts phosphor waste and 0.1 to 0.3 parts permanent magnet waste by weight, preferably 0.5 to 1 part phosphor waste and 0.1 to 0.2 parts permanent magnet waste, for example, the mass ratio of phosphor waste to permanent magnet waste is 10:1, 5:1, 3:1, or 1:1.

[0016] According to an embodiment of the present invention, the rare earth polishing powder waste contains Ce with a content of ≥45% and La with a content of ≥20%, preferably Ce with a content of ≥50% and La with a content of ≥30%, for example, the rare earth polishing powder waste contains rare earth oxides (REO) with a content of ≥80% and CeO2 with a content of ≥55%.

[0017] According to an embodiment of the present invention, the permanent magnet waste is selected from neodymium iron boron waste and / or samarium cobalt waste. Preferably, the Fe content in the neodymium iron boron waste is greater than or equal to 60%, and more preferably, the Fe2O3 content in the neodymium iron boron waste is ≥85%.

[0018] According to an embodiment of the present invention, the content of Y (yttrium) in the phosphor waste is greater than or equal to 30%, and the content of Al is greater than or equal to 15%. For example, the content of Y2O3 in the phosphor waste is ≥40%, and the content of Al2O3 is ≥35%.

[0019] According to an embodiment of the present invention, the rare-earth near-infrared reflective ceramic material has essentially the following properties: Figure 2 XRD patterns shown in (a), 3(a), 4(a), 5(a), and 6(a).

[0020] According to an embodiment of the present invention, the rare-earth near-infrared reflective ceramic material has essentially the following properties: Figure 2 The ultraviolet-visible diffuse reflectance spectra shown in (b), 3(b), 4(b), 5(b), and 6(b) are as follows.

[0021] According to an embodiment of the present invention, the rare earth near-infrared reflective ceramic material is a powder material, and the particle size D of the powder material is... 90 ≤2.5μm, preferably the particle size D of the powdered material 90 ≤2.0μm.

[0022] According to an embodiment of the present invention, the rare earth near-infrared reflective ceramic material is yellow, green, rose red, or blue-green.

[0023] According to an embodiment of the present invention, the rare-earth near-infrared reflective ceramic material has a crystalline phase structure, wherein the crystalline phase structure includes a disordered defect fluorite structure Y2Ce2O7 and a garnet structure Y3Al5O 12 It is an oxide solid solution with the main phase as the main phase.

[0024] According to an embodiment of the present invention, the near-infrared reflectivity of the rare-earth near-infrared reflective ceramic material is ≥70%, preferably ≥75%.

[0025] Secondly, the present invention provides a method for preparing the above-mentioned rare-earth near-infrared reflective ceramic material, comprising the following steps:

[0026] S1. Grind and mix 0-1 parts of rare earth polishing powder waste, 0-1 parts of fluorescent powder waste, and 0-0.3 parts of permanent magnet waste evenly to obtain a mixture;

[0027] S2. The mixture is pressed into a pellet to obtain a preform, which is then calcined in air under normal pressure at a temperature of 1200~1400℃, with a heating rate of 1~8℃ / min and a holding time of 0~6h. After calcination, the pellet is allowed to cool naturally to obtain a near-infrared reflective ceramic material.

[0028] According to an embodiment of the present invention, the particle size of the mixture is less than 0.15 mm, preferably less than 0.1 mm.

[0029] According to an embodiment of the present invention, the calcination temperature is 1250~1350℃, for example, 1200℃, 1300℃, or 1400℃.

[0030] According to an embodiment of the present invention, the heat preservation time is 1 to 5 hours, for example, 2 hours, 3 hours, 4 hours, or 5 hours.

[0031] According to an embodiment of the present invention, the heating rate of the calcination is 2~6℃ / min, for example, 1℃ / min, 2℃ / min, 3℃ / min, 4℃ / min, or 5℃ / min.

[0032] According to an embodiment of the present invention, before step S1, the following steps are also included: crushing, washing and drying, and sieving the samarium cobalt waste.

[0033] According to an embodiment of the present invention, the washing includes ultrasonic cleaning with ethanol 2 to 3 times, and the washing time is 10 to 15 minutes.

[0034] According to an embodiment of the present invention, the drying temperature is 80~100°C.

[0035] According to an embodiment of the present invention, the screening is performed using a standard sieve with a mesh size of 200 to 400.

[0036] According to an embodiment of the present invention, the NdFeB waste, rare earth polishing powder waste, and tri-color phosphor waste only need to be dried and sieved.

[0037] According to an embodiment of the present invention, the drying temperature is 80~100°C.

[0038] According to an embodiment of the present invention, the screening is performed using a standard sieve with a mesh size of 200 to 400.

[0039] According to an embodiment of the present invention, after step S2, the following step is further included: pulverizing the calcined product to a particle size D.90 ≤2.5μm.

[0040] According to embodiments of the present invention, the method of the present invention can stably synthesize disordered defect fluorite structure Y2Ce2O7 and garnet structure Y3Al5O by calcination within a temperature range of 1250~1350℃. 12 During the sintering process, the rate of sintering temperature affects the growth of grains. The heating rate can be in the range of 1~8℃ / min.

[0041] Thirdly, the present invention provides the application of ceramic materials prepared by the above method in near-infrared reflection, such as in vehicles, building walls, etc.

[0042] Fourthly, the present invention also provides a near-infrared reflective coating, the coating comprising the near-infrared reflective ceramic material as described above.

[0043] According to an embodiment of the present invention, the coating is yellow, green, rose red, blue-green, or yellowish-brown.

[0044] According to an embodiment of the present invention, the coating further includes a solvent selected from resins, oils and / or emulsions.

[0045] According to an embodiment of the present invention, the coating further includes auxiliary materials selected from at least one of dispersing agents, binders, film-forming agents, preservatives, leveling agents, and dispersants.

[0046] According to an embodiment of the present invention, the near-infrared reflective coating includes near-infrared reflective coatings and existing coatings, such as near-infrared reflective pigments, alkyd resins and / or protective varnishes.

[0047] Beneficial effects

[0048] (1) This invention creatively uses permanent magnet waste and polishing powder waste containing rare earth elements and phosphor waste as raw materials, and forms Y2Ce2O7 and Y3Al5O7 with disordered defect fluorite structure after high-temperature calcination. 12 This invention utilizes a ceramic solid solution with the main phase to prepare near-infrared reflective ceramic powder, achieving near-full-component high-value utilization of rare earth waste. It directly utilizes permanent magnet waste, polishing powder waste, and rare earth phosphor waste through contact, reaction, nucleation, and crystal growth reactions at the solid interface at high temperatures to generate composite oxides. Rare earth near-infrared reflective ceramic materials are then prepared via a high-temperature solid-state method. This achieves near-full utilization of permanent magnet waste, polishing powder waste, and rare earth phosphor waste. The process only requires high-temperature oxidation, directly utilizing rare earth waste for comprehensive utilization. This breaks through the traditional thinking of separating and purifying valuable elements from waste, avoiding environmental pollution caused by traditional recycling processes such as acid leaching. The process is simple, low-cost, and indirectly achieves energy conservation and emission reduction.

[0049] (2) The rare earth near-infrared reflective ceramic material of the present invention uses polishing powder waste and phosphor waste as the main raw materials to synthesize a ceric acid system with disordered defect fluorite structure and an aluminic acid system with garnet structure. Permanent magnet waste is used as a dopant to adjust the color and near-infrared reflectivity, which can significantly reduce the cost of rare earth near-infrared reflective ceramic material. Moreover, the obtained rare earth near-infrared reflective ceramic material has rich colors and high near-infrared reflectivity.

[0050] (3) The rare earth near-infrared reflective ceramic material of the present invention contains Ce and La elements in the rare earth polishing powder waste, Fe, Pr and Nd elements in the neodymium iron boron waste, Sm, Co and Fe elements in the samarium cobalt waste, and Y and Al elements in the phosphor waste. The higher the content of Ce, La, Y, Al and Sm elements, the higher the near-infrared reflectivity of the ceramic material. The presence of Fe, Pr and Co elements will reduce the near-infrared reflectivity of the ceramic material. As chromogenic groups, they can effectively adjust the color of the ceramic material and obtain a brightly colored rare earth near-infrared reflective ceramic material. Attached Figure Description

[0051] Figure 1 This is a process flow diagram of the method for preparing rare earth near-infrared reflective ceramic materials in this invention.

[0052] Figure 2 The images show the XRD pattern (a) and UV-Vis diffuse reflectance spectrum (b) of the rare earth near-infrared reflective ceramic powder synthesized in Example 1 of this invention.

[0053] Figure 3 The images show the XRD pattern (a) and UV-Vis diffuse reflectance spectrum (b) of the rare earth near-infrared reflective ceramic powder synthesized in Example 2 of this invention.

[0054] Figure 4 The images show the XRD pattern (a) and UV-Vis diffuse reflectance spectrum (b) of the rare earth near-infrared reflective ceramic powder synthesized in Example 3 of this invention.

[0055] Figure 5 The images show the XRD pattern (a) and UV-Vis diffuse reflectance spectrum (b) of the rare earth near-infrared reflective ceramic powder synthesized in Example 4 of this invention.

[0056] Figure 6 The images show the XRD pattern (a) and UV-Vis diffuse reflectance spectrum (b) of the rare earth near-infrared reflective ceramic powder synthesized in Example 5 of this invention. Detailed Implementation

[0057] The preparation method and application of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0058] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0059] The raw materials used in the following examples are as follows:

[0060] The NdFeB waste contains approximately 50% Fe, and approximately 20% Pr, Nd, and Ce; the Samarium Cobalt waste contains approximately 31% Sm, approximately 44% Co, and approximately 16% Fe; the rare earth polishing powder waste contains approximately 45% Ce and approximately 21% La; the waste tri-color phosphor contains approximately 31% Y and approximately 18% Al; all of the above rare earth wastes were provided by China Rare Earth Group.

[0061] Example 1

[0062] Rare earth polishing powder waste and fluorescent powder waste were dried at 80℃ for 2 hours and then passed through a 200-mesh standard sieve for later use.

[0063] Accurately weigh the dried and sieved rare earth polishing powder waste and fluorescent powder waste according to a mass ratio of 1:1, mix them evenly, and then press the powder into briquettes to obtain ceramic powder flakes. Place the pressed ceramic powder flakes into a muffle furnace and calcine them under normal pressure at a calcination temperature of 1200℃ for 3 hours at a heating rate of 5℃ / min. After calcination, allow them to cool naturally to room temperature, and then pulverize the calcined product to a particle size D. 90 ≤2.5μm, to obtain rare earth near-infrared reflective ceramic powder.

[0064] See Figure 2 As shown in (a), the XRD pattern of the rare earth high near-infrared reflectance ceramic powder prepared in this embodiment is shown. It can be seen from the XRD pattern that the powder formed by high-temperature calcination has a disordered defect fluorite structure Y 2-x It is an oxide solid solution with LaCe2O7 as the main phase and has good crystallinity.

[0065] See Figure 2 (b) shows the ultraviolet-visible diffuse reflectance spectrum of the rare earth high near-infrared reflectance ceramic powder prepared in this embodiment. As can be seen from the figure, the rare earth high near-infrared reflectance ceramic powder has a high near-infrared reflectance of about 98.68% in the 750nm~2500nm band. After colorimetric analysis, the color of the ceramic powder is light yellow.

[0066] Example 2

[0067] Rare earth polishing powder waste, fluorescent powder waste, and neodymium iron boron waste are dried at 80℃ for 2 hours and then passed through a 200-mesh standard sieve for later use.

[0068] Accurately weigh the dried and sieved rare earth polishing powder waste, fluorescent powder waste, and NdFeB waste according to a mass ratio of 1:1:0.3, mix them evenly, and then press the powder into briquettes to obtain ceramic powder sheets. Place the pressed ceramic powder sheets into a muffle furnace and calcine them under normal pressure at a temperature of 1400℃ for 5 hours at a heating rate of 3℃ / min. Allow them to cool naturally to room temperature, and then pulverize the calcined product to a particle size D. 90 ≤2.5μm, to obtain rare earth near-infrared reflective ceramic powder.

[0069] See Figure 3 As shown in (a), the XRD pattern of the rare earth high near-infrared reflectance ceramic powder prepared in this embodiment can be seen from the XRD pattern. After high-temperature calcination, a disordered defect fluorite structure Y is formed. 2-x It is an oxide solid solution with LaCe2O7 as the main phase and has good crystallinity.

[0070] See Figure 3 (b) shows the ultraviolet-visible diffuse reflectance spectrum of the rare earth high near-infrared reflectance ceramic powder prepared in this embodiment. As can be seen from the figure, the rare earth high near-infrared reflectance ceramic powder has a high near-infrared reflectance of about 75.24% in the 750nm~2500nm band. After colorimetric analysis, the color of the ceramic powder is brown.

[0071] Example 3

[0072] Rare earth polishing powder waste, fluorescent powder waste, and samarium cobalt waste are dried at 80℃ for 2 hours and then passed through a 200-mesh standard sieve for later use.

[0073] Accurately weigh the dried and sieved rare earth polishing powder waste, fluorescent powder waste, and samarium cobalt waste according to the mass ratio of 1:1:0.1, mix them evenly, and then press the powder into briquettes to obtain ceramic powder sheets. Place the pressed ceramic powder sheets into a muffle furnace and calcine them under normal pressure at a calcination temperature of 1200℃ for 1 hour at a heating rate of 3℃ / min. Allow them to cool naturally to room temperature, and then pulverize the calcined product to a particle size D90≤2.5μm to obtain rare earth near-infrared reflective ceramic powder.

[0074] See Figure 4 As shown in (a), the XRD pattern of the rare earth high near-infrared reflectance ceramic powder prepared in this embodiment can be seen from the XRD pattern. After high-temperature calcination, a disordered defect fluorite structure Y is formed. 2-xIt is an oxide solid solution with LaCe2O7 as the main phase and has good crystallinity.

[0075] See Figure 4 (b) shows the ultraviolet-visible diffuse reflectance spectrum of the rare earth high near-infrared reflectance ceramic powder prepared in this embodiment. As can be seen from the figure, the rare earth high near-infrared reflectance ceramic powder has a high near-infrared reflectance of about 70.77% in the 750nm~2500nm band. After colorimetric analysis, the color of the ceramic powder is blue-green.

[0076] Example 4

[0077] After drying the NdFeB waste and phosphor waste at 80℃ for 2 hours, they are passed through a 200-mesh standard sieve for later use.

[0078] Accurately weigh the dried and sieved phosphor waste and NdFeB waste according to a mass ratio of 1:0.2, mix them evenly, and then press the powder into briquettes to obtain ceramic powder sheets. Place the pressed ceramic powder sheets into a muffle furnace and calcine them under normal pressure at a calcination temperature of 1300℃ for 3 hours at a heating rate of 3℃ / min. Allow them to cool naturally, and then pulverize the calcined product to a particle size D. 90 ≤2.5μm, to obtain rare earth near-infrared reflective ceramic powder.

[0079] See Figure 5 As shown in (a), the XRD pattern of the rare earth high near-infrared reflectance ceramic powder prepared in this embodiment can be seen from the XRD pattern. After high-temperature calcination, a Y3Al structure with garnet was formed. 5-x FeO 12 It is an oxide solid solution with good crystallinity, and is mainly composed of oxides.

[0080] See Figure 5 (b) shows the ultraviolet-visible diffuse reflectance spectrum of the rare earth high near-infrared reflectance ceramic powder prepared in this embodiment. As can be seen from the figure, the rare earth high near-infrared reflectance ceramic powder has a high near-infrared reflectance of about 80.67% in the 750nm~2500nm band. After colorimetric analysis, the color of the ceramic powder is green.

[0081] Example 5

[0082] After drying neodymium iron boron waste and rare earth polishing powder waste at 80℃ for 2 hours, they are passed through a 200-mesh standard sieve for later use.

[0083] Accurately weigh the dried and sieved rare earth polishing powder waste and NdFeB waste according to a mass ratio of 1:0.1, mix them evenly, and press the powder into briquettes to obtain ceramic powder flakes. Place the pressed ceramic powder flakes into a muffle furnace and calcine them under normal pressure at a calcination temperature of 1200℃ for 1 hour at a heating rate of 3℃ / min. After naturally cooling to room temperature, pulverize the calcined product to a particle size D. 90 ≤2.5μm, to obtain rare earth near-infrared reflective ceramic powder.

[0084] See Figure 6 As shown in (a), this is the XRD pattern of the ceramic powder prepared in this embodiment. Figure 5 As can be seen from the XRD pattern, after high-temperature calcination, an oxide solid solution with La2Ce2O7 as the main phase and disordered defect fluorite structure was formed, with good crystallinity.

[0085] See Figure 6 (b) shows the ultraviolet-visible diffuse reflectance spectrum of the rare earth high near-infrared reflectance ceramic powder prepared in this embodiment. As can be seen from the figure, the ceramic powder has a high near-infrared reflectance of about 85.54% in the 750nm~2500nm band. After colorimetric analysis, the color of the ceramic powder is magenta.

[0086] In Example 2, rare earth polishing powder waste, phosphor waste, and neodymium iron boron waste are mixed to generate Y-type fluorite with disordered defect structure. 2-x The LaCe2O7-based oxide solid solution has a large band gap, resulting in higher near-infrared reflectance compared to Examples 4 and 5. In addition, compared to Example 1, the addition of Fe and Pr chromophores in the NdFeB waste in Example 2 changes the color of the ceramic material from light yellow to brown, while the addition of Co chromophores in the Samarium-Cobalt waste in Example 3 changes the color of the ceramic material from light yellow to blue-green.

[0087] The specific embodiments of the present invention have been described above by way of example. However, the scope of protection of the present invention is not limited to the above exemplary embodiments. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for producing a rare earth near-infrared reflective ceramic material, characterized by, The method comprises the following steps: S1. grinding and mixing rare earth near-infrared reflective ceramic materials uniformly to obtain a mixture; S2. tabletting the mixture to obtain a green body, and calcining the green body in an air atmosphere under normal pressure, wherein the calcination temperature is 1250-1350℃, the heating rate is 1-8℃ / min, the holding time is 1-5h, and the calcined product is cooled naturally to obtain a near-infrared reflective ceramic material; The rare earth near-infrared reflective ceramic material comprises any one of components a)-d): a) the rare earth near-infrared reflective ceramic material comprises 0.1-1 parts of rare earth polishing powder waste, 0.1-1 parts of fluorescent powder waste, and 0.1-0.3 parts of permanent magnet waste by mass fraction; b) the rare earth near-infrared reflective ceramic material comprises 0.1-1 parts of rare earth polishing powder waste and 0.1-1 parts of fluorescent powder waste by mass fraction; c) the rare earth near-infrared reflective ceramic material comprises 0.1-1 parts of rare earth polishing powder waste and 0.1-0.3 parts of permanent magnet waste by mass fraction; d) the rare earth near-infrared reflective ceramic material comprises 0.1-1 parts of fluorescent powder waste and 0.1-0.3 parts of permanent magnet waste by mass fraction; The content of Ce in the rare earth polishing powder waste is greater than or equal to 45%, and the content of La is greater than or equal to 20%; The permanent magnet waste is selected from neodymium-iron-boron waste, and the content of Fe in the neodymium-iron-boron waste is greater than or equal to 60%; The content of Y in the fluorescent powder waste is greater than or equal to 30%, and the content of Al is greater than or equal to 15%; The rare earth near-infrared reflective ceramic material has a crystalline phase structure including Y2Ce2O7, La2Ce2O7, or Y3Al5O 12 oxide solid solution as a main phase.

2. The method for preparing rare-earth near-infrared reflective ceramic material according to claim 1, characterized in that, The rare earth near-infrared reflective ceramic material is a powdery material, the particle size D 90 ≤ 2.5 μm.

3. The method for preparing rare-earth near-infrared reflective ceramic material according to claim 1, characterized in that, The color of the rare earth near-infrared reflective ceramic material is light yellow, green, rose or brown.

4. Process for the production of a rare earth near-infrared reflecting ceramic material according to any one of claims 1 to 3, characterized in that The near-infrared reflectivity of the rare earth near-infrared reflective ceramic material is greater than or equal to 70%.

5. The method of claim 1-3, wherein the method is characterized by, The heating rate of the calcination is 2-6℃ / min.

6. A near-infrared reflective ceramic material prepared by the method of any one of claims 1-5 for use in near-infrared reflection.

7. A near infrared reflective coating characterized in that, The coating comprises a near-infrared reflective ceramic material prepared by the method of any one of claims 1-5.

8. The near infrared reflective coating of claim 7, wherein, The coating further comprises a solvent selected from resins, oils and / or emulsions.

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