Infrared ray porous ceramic plate fired at low temperature and preparation method thereof

Abstract

The invention discloses a preparation method of a low-temperature fired infrared porous ceramic plate. The preparation method comprises the following steps: (1) preparing composite oxide powder; (2) preparing coating powder; (3) soaking the coated powder in an aqueous solution of lithium acetate, filtering, drying and calcining to obtain modified powder; and (4) uniformly mixing celsian powder, quartz powder, barium aluminum silicate powder, the composite oxide powder, the modified powder and sodium tripolyphosphate to obtain mixed powder, adding water to adjust the water content, pressing into a plate blank, drying, calcining, and cooling along with a furnace to obtain the infrared porous ceramic plate. The ceramic plate prepared by the method has good far infrared ray emissivity and strength, the application performance of the ceramic material in the aspects of decoration, heat preservation, air purification and the like is improved, and the durability of the ceramic is improved.

Description

Technical Field

[0001] This invention relates to the field of functional ceramic materials technology, and in particular to a low-temperature sintered infrared porous ceramic plate and its preparation method. Background Technology

[0002] Since the discovery of infrared radiation, infrared technology has been extensively and deeply studied, with the research of high-emissivity materials becoming a hot topic. Ceramic materials, composed of polyatomic molecules with macromolecular structures, exhibit high emissivity because the vibration of these polyatomic atoms easily alters the molecular symmetry, causing changes in the dipole moment. Therefore, obtaining infrared radiation materials with high emissivity using ceramic preparation techniques has become an increasingly important research focus. Infrared ceramic materials are made by mixing inorganic compounds and trace metal elements or specific natural minerals in different proportions, followed by high-temperature sintering to achieve high emissivity and radiation intensity within a certain infrared wavelength range. Researching and optimizing the selection of raw materials, the proportions of the formulation, and the sintering process are key to obtaining high infrared emissivity. Summary of the Invention

[0003] Therefore, the present invention provides a method for preparing a low-temperature sintered infrared porous ceramic plate, the steps of which include: (1) Prepare a composite aqueous solution of cerium nitrate and manganese nitrate in a reaction vessel. Add ethylene glycol to the composite aqueous solution of cerium nitrate and manganese nitrate under stirring. After the addition is completed, stir for more than 10 minutes. Then, add acetic acid and polyvinylpyrrolidone to the solution under stirring. After the addition is completed, stir for more than 30 minutes. Then seal the reaction vessel and heat it to 180-190℃ and keep it at that temperature for more than 20 hours. Then, cool it naturally to room temperature. Open the reaction vessel and add sodium hydroxide solution. After the addition is completed, stir for more than 30 minutes. Then, separate the solid and liquid phases. Wash the solid phase with deionized water, dry it, and then calcine it at 500-550℃ for more than 3 hours to obtain composite oxide powder. (2) Prepare a composite aqueous solution of copper sulfate and ferrous sulfate, and a composite ethanol solution of zinc acetate and praseodymium acetate; keep the composite aqueous solution of copper sulfate and ferrous sulfate at a constant temperature of 45±5℃ in a water bath, and then add sodium carbonate solution to the solution under stirring. After the addition is completed, continue stirring at a constant temperature of 45±5℃ for more than 2 hours. Then, separate the solid and liquid phases, wash the solid phase with deionized water, dry it, and soak the dried solid phase in the composite ethanol solution of zinc acetate and praseodymium acetate to obtain a mixture. Keep the mixture under negative pressure for more than 2 hours, and then separate the solid and liquid phases. Calcine the solid phase at 400~450℃ for more than 3 hours to obtain coated powder. (3) Prepare an aqueous solution of lithium acetate, immerse the coated powder in the aqueous solution of lithium acetate, stir for more than 5 minutes, then filter, dry in solid phase, calcine at 500-550°C for more than 1 hour after drying, then cool naturally to room temperature, immerse again in the aqueous solution of lithium acetate, stir for more than 5 minutes, filter, dry in solid phase, calcine at 500-550°C for more than 5 hours after drying to obtain the modified powder; (4) Mix barium feldspar powder, quartz powder, barium aluminum silicate powder, the composite oxide powder, the modified powder, and sodium tripolyphosphate evenly to obtain a mixed powder. Add water to the mixed powder to adjust the moisture content, then press it into a slab. The slab is dried and then calcined at 1140-1160°C and then cooled in the furnace to obtain the infrared porous ceramic plate.

[0004] Further, in step (1), the concentration of cerium nitrate in the composite aqueous solution of cerium nitrate and manganese nitrate is 8-10 g / 100 mL, the concentration of manganese nitrate is 3-4 g / 100 mL, and the solvent is water; the ratio of ethylene glycol, acetic acid, polyvinylpyrrolidone, and sodium hydroxide solution added to the composite aqueous solution of cerium nitrate and manganese nitrate is: composite aqueous solution of cerium nitrate and manganese nitrate: ethylene glycol: acetic acid: polyvinylpyrrolidone: sodium hydroxide solution = 10 mL: 20-25 mL: 0.8-1 mL: 0.5-0.8 g: 5-8 mL, wherein the mass percentage of solute in the sodium hydroxide solution is 20%-25%.

[0005] Further, in step (2), in the composite aqueous solution of copper sulfate and ferrous sulfate, the concentration of copper sulfate is 5-8 g / 100 mL, the concentration of ferrous sulfate is 10-12 g / 100 mL, and the solvent is water; in the composite ethanol solution of zinc acetate and praseodymium acetate, the concentration of zinc acetate is 20-22 g / L, the concentration of praseodymium acetate is 2-4 g / L, and the solvent is ethanol.

[0006] Further, in step (2), the volume ratio of sodium carbonate solution added to the composite aqueous solution of copper sulfate and ferrous sulfate is 10:3-5, the concentration of sodium carbonate in the sodium carbonate solution is 18-20 g / 100 mL, and the solvent is water.

[0007] Further, in step (2), the solid-liquid mass ratio of the dried solid phase immersed in the composite ethanol solution of zinc acetate and praseodymium acetate is 1:50 to 200.

[0008] Further, in step (3), the concentration of lithium acetate in the aqueous solution of lithium acetate is 22-25 g / 100 mL; the ratio of the amount of coating powder soaked in the aqueous solution of lithium acetate is 1 g of coating powder to 50-100 g of aqueous solution of lithium acetate.

[0009] Further, in step (4), the barium feldspar powder, quartz powder, barium aluminum silicate powder, composite oxide powder, modifying powder, and sodium tripolyphosphate are in the following weight parts: 25 parts barium feldspar powder, 12-18 parts quartz powder, 6-8 parts barium aluminum silicate powder, 3-10 parts composite oxide powder, 5-8 parts modifying powder, and 1.8-2.2 parts sodium tripolyphosphate.

[0010] The beneficial effects of this invention are as follows: the ceramic plate prepared by the method described in this invention has good far-infrared emissivity and intensity, improving the application performance of ceramic materials in decoration, heat insulation, air purification, etc., and improving the durability of ceramics. This may be because this invention first adds cerium-manganese composite oxide to the ceramic. During the ceramic sintering process, cerium can induce the crystallization process, promote the occurrence of ceramic lattice distortion, and enhance the vibrational activity of the lattice. The addition of manganese and subsequent copper and iron elements helps to reduce lattice symmetry and enhance the anharmonic effect of lattice vibration, thereby improving the far-infrared emissivity of the ceramic. Subsequently, by coating with zinc-praseodymium composite oxide, praseodymium ions are added to the ceramic crystal, introducing impurity energy levels into the crystal structure and facilitating the escape of oxygen atoms from the lattice to form oxygen vacancies. This increases electrons and holes, promoting carrier absorption. At the same time, the presence of the radius difference between praseodymium ions and cerium / barium, as well as the introduction of oxygen vacancies, can further induce lattice distortion, thereby enhancing the effect of lattice vibration on far-infrared radiation. Furthermore, doping with praseodymium can optimize the surface state of the coated powder, providing better conditions for subsequent lithium modification. Finally, the lithium oxide modification process forms a lithium oxide layer, which promotes the sintering process of ceramics. During sintering, it easily forms a composite phase with silicon dioxide, lowering the sintering temperature and greatly reducing microcrack defects inside the ceramic, thereby improving the strength of the ceramic material. Attached Figure Description

[0011] Figure 1 A comparison of the infrared emissivity of ceramic plates prepared by the methods described in the various embodiments and comparative examples; Figure 2 The diagram shows a comparison of the bending strength of ceramic plates prepared by the methods described in the various embodiments and comparative examples. Detailed Implementation

[0012] The present invention will be further described below with reference to the embodiments.

[0013] Example 1 A method for preparing a low-temperature sintered infrared porous ceramic plate, comprising the following steps: (1) Prepare a composite aqueous solution of cerium nitrate and manganese nitrate in a reaction vessel. The concentration of cerium nitrate in the composite aqueous solution is 8 g / 100 mL, the concentration of manganese nitrate is 3 g / 100 mL, and the solvent is water. Add ethylene glycol to the composite aqueous solution of cerium nitrate and manganese nitrate under stirring. After the addition is complete, stir for 10 min. Then, add acetic acid and polyvinylpyrrolidone (K30) to the solution under stirring. After the addition is complete, stir for another 30 min. Then seal the reaction vessel, heat to 180℃ and keep at that temperature for 20 h. Then, allow it to cool naturally to room temperature and open the reaction vessel. Add sodium hydroxide solution. The ratio of ethylene glycol, acetic acid, polyvinylpyrrolidone, and sodium hydroxide solution added to the composite aqueous solution of cerium nitrate and manganese nitrate is 10 mL: 20 mL: 0.8 mL: 0.5 g: 5 mL, wherein the mass percentage of solute in the sodium hydroxide solution is 20%. After the addition is completed, stir for 30 min, then separate the solid and liquid phases. Wash the solid phase three times with deionized water, dry it at 60 °C for 2 h, and then calcine it at 500 °C for 3 h to obtain composite oxide powder. (2) Prepare a composite aqueous solution of copper sulfate and ferrous sulfate, wherein the concentration of copper sulfate is 5 g / 100 mL, the concentration of ferrous sulfate is 10 g / 100 mL, and the solvent is water; prepare a composite ethanol solution of zinc acetate and praseodymium acetate, wherein the concentration of zinc acetate is 20 g / L, the concentration of praseodymium acetate is 2 g / L, and the solvent is ethanol; keep the composite aqueous solution of copper sulfate and ferrous sulfate at a constant temperature of 45°C in a water bath, and then add sodium carbonate solution to the solution while stirring, wherein the volume ratio of sodium carbonate solution added to the composite aqueous solution of copper sulfate and ferrous sulfate is copper sulfate to ferrous sulfate. A composite aqueous solution of ferrous acetate and sodium carbonate solution was prepared at a ratio of 10:3, wherein the concentration of sodium carbonate in the sodium carbonate solution was 18 g / 100 mL, and the solvent was water. After the addition of the materials, the mixture was stirred at a constant temperature of 45 °C for 2 h, and then the solid and liquid phases were separated. The solid phase was washed three times with deionized water and dried at 60 °C for 2 h. The dried solid phase was then immersed in a composite ethanol solution of zinc acetate and praseodymium acetate to obtain a mixture. The solid-liquid mass ratio of the dried solid phase immersed in the composite ethanol solution of zinc acetate and praseodymium acetate was 1:50. The mixture was held under negative pressure (0.01 standard atmospheres) for 2 h, and then the solid and liquid phases were separated. The solid phase was calcined at 400 °C for 3 h to obtain a coated powder. (3) Prepare an aqueous solution of lithium acetate, wherein the concentration of lithium acetate in the aqueous solution of lithium acetate is 22 g / 100 mL; immerse the coated powder in the aqueous solution of lithium acetate, wherein the ratio of the coated powder to the aqueous solution of lithium acetate is 1 g: 50 g; stir for 5 min, then filter, dry the solid phase at 100 °C for 10 min, calcine at 500 °C for 1 h after drying, then cool naturally to room temperature, and after cooling, immerse the powder in the aqueous solution of lithium acetate again according to the same process as above, stir for 5 min, filter, dry the solid phase at 100 °C for 10 min, but calcine at 500 °C for 5 h after drying to obtain the modified powder; (4) Barium feldspar powder, quartz powder, barium aluminum silicate powder, the composite oxide powder, the modifying powder, and sodium tripolyphosphate are mixed evenly to obtain a mixed powder. The weight parts of the barium feldspar powder, quartz powder, barium aluminum silicate powder, the composite oxide powder, the modifying powder, and sodium tripolyphosphate are as follows: 25 parts barium feldspar powder, 12 parts quartz powder, 6 parts barium aluminum silicate powder, 3 parts composite oxide powder, 5 parts modifying powder, and 1.8 parts sodium tripolyphosphate. Water is added to the mixed powder to adjust the moisture content to 10 wt%, and then it is pressed into a slab under a pressure of 40 MPa. The slab is dried at 80°C for 30 min, then calcined at 1140°C for 3 h, and then cooled in the furnace to obtain the infrared porous ceramic plate.

[0014] Example 2 A method for preparing a low-temperature sintered infrared porous ceramic plate, comprising the following steps: (1) Prepare a composite aqueous solution of cerium nitrate and manganese nitrate in a reaction vessel. The concentration of cerium nitrate in the composite aqueous solution is 9 g / 100 mL, the concentration of manganese nitrate is 3 g / 100 mL, and the solvent is water. Ethylene glycol is added to the composite aqueous solution of cerium nitrate and manganese nitrate under stirring. After the addition is completed, stir for 10 min. Then, acetic acid and polyvinylpyrrolidone (K30) are added to the solution under stirring. After the addition is completed, stir for another 30 min. Then, seal the reaction vessel, heat to 180℃ and keep at that temperature for 20 h. Then, allow it to cool naturally to room temperature and open the reaction vessel. Add sodium hydroxide solution. The ratio of ethylene glycol, acetic acid, polyvinylpyrrolidone, and sodium hydroxide solution added to the composite aqueous solution of cerium nitrate and manganese nitrate is 10 mL: 22 mL: 0.9 mL: 0.6 g: 6 mL, wherein the mass percentage of solute in the sodium hydroxide solution is 20%. After the addition is completed, stir for 30 min, then separate the solid and liquid phases. Wash the solid phase three times with deionized water, dry it at 60 °C for 2 h, and then calcine it at 500 °C for 3 h to obtain composite oxide powder. (2) Prepare a composite aqueous solution of copper sulfate and ferrous sulfate, wherein the concentration of copper sulfate is 6 g / 100 mL, the concentration of ferrous sulfate is 11 g / 100 mL, and the solvent is water; prepare a composite ethanol solution of zinc acetate and praseodymium acetate, wherein the concentration of zinc acetate is 21 g / L, the concentration of praseodymium acetate is 3 g / L, and the solvent is ethanol; keep the composite aqueous solution of copper sulfate and ferrous sulfate at a constant temperature of 45°C in a water bath, and then add sodium carbonate solution to the solution while stirring, wherein the volume ratio of sodium carbonate solution added to the composite aqueous solution of copper sulfate and ferrous sulfate is copper sulfate to ferrous sulfate. A composite aqueous solution of ferrous acetate and sodium carbonate solution was prepared at a ratio of 10:4, wherein the concentration of sodium carbonate in the sodium carbonate solution was 18 g / 100 mL, and the solvent was water. After the addition of the materials, the mixture was stirred at a constant temperature of 45 °C for 2 h, and then the solid and liquid phases were separated. The solid phase was washed three times with deionized water and dried at 60 °C for 2 h. The dried solid phase was then immersed in a composite ethanol solution of zinc acetate and praseodymium acetate to obtain a mixture. The solid-liquid mass ratio of the dried solid phase immersed in the composite ethanol solution of zinc acetate and praseodymium acetate was 1:50. The mixture was held under negative pressure (0.01 standard atmospheres) for 2 h, and then the solid and liquid phases were separated. The solid phase was calcined at 400 °C for 3 h to obtain a coated powder. (3) Prepare an aqueous solution of lithium acetate, wherein the concentration of lithium acetate in the aqueous solution of lithium acetate is 23 g / 100 mL; immerse the coated powder in the aqueous solution of lithium acetate, wherein the ratio of the coated powder to the aqueous solution of lithium acetate is 1 g: 50 g; stir for 5 min, then filter, dry the solid phase at 100 °C for 10 min, calcine at 500 °C for 1 h after drying, then cool naturally to room temperature, and after cooling, immerse the powder in the aqueous solution of lithium acetate again according to the same process as above, stir for 5 min, filter, dry the solid phase at 100 °C for 10 min, but calcine at 500 °C for 5 h after drying to obtain the modified powder; (4) Barium feldspar powder, quartz powder, barium aluminum silicate powder, the composite oxide powder, the modifying powder, and sodium tripolyphosphate are mixed evenly to obtain a mixed powder. The barium feldspar powder, quartz powder, barium aluminum silicate powder, the composite oxide powder, the modifying powder, and sodium tripolyphosphate are in the following weight parts: 25 parts barium feldspar powder, 14 parts quartz powder, 7 parts barium aluminum silicate powder, 6 parts composite oxide powder, 6 parts modifying powder, and 2 parts sodium tripolyphosphate. Water is added to the mixed powder to adjust the moisture content to 10 wt%, and then it is pressed into a slab under a pressure of 40 MPa. The slab is dried at 80°C for 30 min, then calcined at 1150°C for 3 h, and then cooled in the furnace to obtain the infrared porous ceramic plate.

[0015] Example 3 A method for preparing a low-temperature sintered infrared porous ceramic plate, comprising the following steps: (1) Prepare a composite aqueous solution of cerium nitrate and manganese nitrate in a reactor. The concentration of cerium nitrate in the composite aqueous solution is 9 g / 100 mL, the concentration of manganese nitrate is 4 g / 100 mL, and the solvent is water. Ethylene glycol is added to the composite aqueous solution of cerium nitrate and manganese nitrate under stirring. After the addition is complete, stir for 10 min. Then, acetic acid and polyvinylpyrrolidone (K30) are added to the solution under stirring. After the addition is complete, stir for another 30 min. Then, seal the reactor, heat to 190℃ and keep at that temperature for 20 h, then allow it to cool naturally to room temperature. Open the reactor and add... Add sodium hydroxide solution to the composite aqueous solution of cerium nitrate and manganese nitrate. The ratio of ethylene glycol, acetic acid, polyvinylpyrrolidone, and sodium hydroxide solution is: composite aqueous solution of cerium nitrate and manganese nitrate: ethylene glycol: acetic acid: polyvinylpyrrolidone: sodium hydroxide solution = 10 mL: 24 mL: 0.9 mL: 0.7 g: 7 mL, wherein the mass percentage of solute in the sodium hydroxide solution is 20%. After the addition is completed, stir for 30 min, then separate the solid and liquid phases. Wash the solid phase three times with deionized water, dry it at 60 °C for 2 h, and then calcine it at 500–550 °C for 3 h to obtain composite oxide powder. (2) Prepare a composite aqueous solution of copper sulfate and ferrous sulfate, wherein the concentration of copper sulfate is 7 g / 100 mL, the concentration of ferrous sulfate is 11 g / 100 mL, and the solvent is water; prepare a composite ethanol solution of zinc acetate and praseodymium acetate, wherein the concentration of zinc acetate is 21 g / L, the concentration of praseodymium acetate is 3 g / L, and the solvent is ethanol; keep the composite aqueous solution of copper sulfate and ferrous sulfate at a constant temperature of 45°C in a water bath, and then add sodium carbonate solution to the solution while stirring, wherein the volume ratio of sodium carbonate solution added to the composite aqueous solution of copper sulfate and ferrous sulfate is copper sulfate to ferrous sulfate. A composite aqueous solution of ferrous acetate and sodium carbonate solution was prepared at a ratio of 10:4, wherein the concentration of sodium carbonate in the sodium carbonate solution was 20 g / 100 mL, and the solvent was water. After the addition of the materials, the mixture was stirred at a constant temperature of 45 °C for 2 h, and then the solid and liquid phases were separated. The solid phase was washed three times with deionized water and dried at 60 °C for 2 h. The dried solid phase was then immersed in a composite ethanol solution of zinc acetate and praseodymium acetate to obtain a mixture. The solid-liquid mass ratio of the dried solid phase immersed in the composite ethanol solution of zinc acetate and praseodymium acetate was 1:50. The mixture was held under negative pressure (0.01 standard atmospheres) for 2 h, and then the solid and liquid phases were separated. The solid phase was calcined at 450 °C for 3 h to obtain a coated powder. (3) Prepare an aqueous solution of lithium acetate, wherein the concentration of lithium acetate in the aqueous solution of lithium acetate is 25 g / 100 mL; immerse the coated powder in the aqueous solution of lithium acetate, wherein the ratio of the coated powder to the aqueous solution of lithium acetate is 1 g: 50 g; stir for 5 min, then filter, dry the solid phase at 100 °C for 10 min, calcine at 500 °C for 1 h after drying, then cool naturally to room temperature, and after cooling, immerse the powder in the aqueous solution of lithium acetate again according to the same process as above, stir for 5 min, filter, dry the solid phase at 100 °C for 10 min, but calcine at 500 °C for 5 h after drying to obtain the modified powder; (4) Barium feldspar powder, quartz powder, barium aluminum silicate powder, the composite oxide powder, the modifying powder, and sodium tripolyphosphate are mixed evenly to obtain a mixed powder. The barium feldspar powder, quartz powder, barium aluminum silicate powder, the composite oxide powder, the modifying powder, and sodium tripolyphosphate are in the following weight parts: 25 parts barium feldspar powder, 16 parts quartz powder, 7 parts barium aluminum silicate powder, 8 parts composite oxide powder, 7 parts modifying powder, and 2 parts sodium tripolyphosphate. Water is added to the mixed powder to adjust the moisture content to 10 wt%, and then it is pressed into a slab under a pressure of 40 MPa. The slab is dried at 80°C for 30 min, then calcined at 1150°C for 3 h, and then cooled in the furnace to obtain the infrared porous ceramic plate.

[0016] Example 4 A method for preparing a low-temperature sintered infrared porous ceramic plate, comprising the following steps: (1) Prepare a composite aqueous solution of cerium nitrate and manganese nitrate in a reaction vessel. The concentration of cerium nitrate in the composite aqueous solution is 10 g / 100 mL, the concentration of manganese nitrate is 4 g / 100 mL, and the solvent is water. Add ethylene glycol to the composite aqueous solution of cerium nitrate and manganese nitrate under stirring. After the addition is complete, stir for 10 min. Then, add acetic acid and polyvinylpyrrolidone (K30) to the solution under stirring. After the addition is complete, stir for another 30 min. Then seal the reaction vessel, heat to 190℃ and keep at that temperature for 20 h. Then, allow it to cool naturally to room temperature and open the reaction vessel. Add sodium hydroxide solution. The ratio of ethylene glycol, acetic acid, polyvinylpyrrolidone, and sodium hydroxide solution added to the composite aqueous solution of cerium nitrate and manganese nitrate is 10 mL: 25 mL: 1 mL: 0.8 g: 8 mL, where the mass percentage of solute in the sodium hydroxide solution is 20%. After the addition is completed, stir for 30 min, then separate the solid and liquid phases. Wash the solid phase three times with deionized water, dry it at 60 °C for 2 h, and then calcine it at 500–550 °C for 3 h to obtain composite oxide powder. (2) Prepare a composite aqueous solution of copper sulfate and ferrous sulfate, wherein the concentration of copper sulfate is 8 g / 100 mL, the concentration of ferrous sulfate is 12 g / 100 mL, and the solvent is water; prepare a composite ethanol solution of zinc acetate and praseodymium acetate, wherein the concentration of zinc acetate is 22 g / L, the concentration of praseodymium acetate is 4 g / L, and the solvent is ethanol; keep the composite aqueous solution of copper sulfate and ferrous sulfate at a constant temperature of 45°C in a water bath, and then add sodium carbonate solution to the solution while stirring, wherein the volume ratio of sodium carbonate solution added to the composite aqueous solution of copper sulfate and ferrous sulfate is copper sulfate to ferrous sulfate. A composite aqueous solution of ferrous acetate and sodium carbonate solution was prepared at a ratio of 10:5, wherein the concentration of sodium carbonate in the sodium carbonate solution was 20 g / 100 mL, and the solvent was water. After the addition of the materials, the mixture was stirred at a constant temperature of 45 °C for 2 h, and then the solid and liquid phases were separated. The solid phase was washed three times with deionized water and dried at 60 °C for 2 h. The dried solid phase was then immersed in a composite ethanol solution of zinc acetate and praseodymium acetate to obtain a mixture. The solid-liquid mass ratio of the dried solid phase immersed in the composite ethanol solution of zinc acetate and praseodymium acetate was 1:50. The mixture was held under negative pressure (0.01 standard atmospheres) for 2 h, and then the solid and liquid phases were separated. The solid phase was calcined at 450 °C for 3 h to obtain a coated powder. (3) Prepare an aqueous solution of lithium acetate, wherein the concentration of lithium acetate in the aqueous solution of lithium acetate is 25 g / 100 mL; immerse the coated powder in the aqueous solution of lithium acetate, wherein the ratio of the coated powder to the aqueous solution of lithium acetate is 1 g: 50 g; stir for 5 min, then filter, dry the solid phase at 100 °C for 10 min, calcine at 500 °C for 1 h after drying, then cool naturally to room temperature, and after cooling, immerse the powder in the aqueous solution of lithium acetate again according to the same process as above, stir for 5 min, filter, dry the solid phase at 100 °C for 10 min, but calcine at 500 °C for 5 h after drying to obtain the modified powder; (4) Barium feldspar powder, quartz powder, barium aluminum silicate powder, the composite oxide powder, the modifying powder, and sodium tripolyphosphate are mixed evenly to obtain a mixed powder. The weight parts of the barium feldspar powder, quartz powder, barium aluminum silicate powder, the composite oxide powder, the modifying powder, and sodium tripolyphosphate are as follows: 25 parts barium feldspar powder, 18 parts quartz powder, 8 parts barium aluminum silicate powder, 10 parts composite oxide powder, 8 parts modifying powder, and 2.2 parts sodium tripolyphosphate. Water is added to the mixed powder to adjust the moisture content to 10 wt%, and then it is pressed into a slab under a pressure of 40 MPa. The slab is dried at 80°C for 30 min, then calcined at 1160°C for 3 h, and then cooled in the furnace to obtain the infrared porous ceramic plate.

[0017] Comparative Example 1 A method for preparing a ceramic plate as a comparison includes the following steps: (1) Prepare an aqueous solution of cerium nitrate in a reaction vessel, wherein the concentration of cerium nitrate in the aqueous solution is 9 g / 100 mL, and the solvent is water; add ethylene glycol to the aqueous solution of cerium nitrate while stirring, and stir for 10 min after the addition is complete; then add acetic acid and polyvinylpyrrolidone (K30) to the solution while stirring, and stir for another 30 min after the addition is complete; then seal the reaction vessel, heat to 190℃ and keep at that temperature for 20 h, then allow it to cool naturally to room temperature; open the reaction vessel, add sodium hydroxide solution, and the cerium nitrate solution is added to the solution. The following steps are performed: Ethylene glycol, acetic acid, polyvinylpyrrolidone, and sodium hydroxide solution are added to an aqueous solution of cerium nitrate in the following ratio: aqueous solution of cerium nitrate: ethylene glycol: acetic acid: polyvinylpyrrolidone: sodium hydroxide solution = 10 mL: 24 mL: 0.9 mL: 0.7 g: 7 mL, wherein the mass percentage of solute in the sodium hydroxide solution is 20%. After the addition is completed, the mixture is stirred for 30 min, then the solid and liquid phases are separated. The solid phase is washed three times with deionized water, dried at 60 °C for 2 h, and then calcined at 500–550 °C for 3 h to obtain cerium oxide powder. (2) Prepare a composite aqueous solution of copper sulfate and ferrous sulfate, wherein the concentration of copper sulfate is 7 g / 100 mL, the concentration of ferrous sulfate is 11 g / 100 mL, and the solvent is water; prepare a composite ethanol solution of zinc acetate and praseodymium acetate, wherein the concentration of zinc acetate is 21 g / L, the concentration of praseodymium acetate is 3 g / L, and the solvent is ethanol; keep the composite aqueous solution of copper sulfate and ferrous sulfate at a constant temperature of 45°C in a water bath, and then add sodium carbonate solution to the solution while stirring, wherein the volume ratio of sodium carbonate solution added to the composite aqueous solution of copper sulfate and ferrous sulfate is copper sulfate to ferrous sulfate. A composite aqueous solution of ferrous acetate and sodium carbonate solution was prepared at a ratio of 10:4, wherein the concentration of sodium carbonate in the sodium carbonate solution was 20 g / 100 mL, and the solvent was water. After the addition of the materials, the mixture was stirred at a constant temperature of 45 °C for 2 h, and then the solid and liquid phases were separated. The solid phase was washed three times with deionized water and dried at 60 °C for 2 h. The dried solid phase was then immersed in a composite ethanol solution of zinc acetate and praseodymium acetate to obtain a mixture. The solid-liquid mass ratio of the dried solid phase immersed in the composite ethanol solution of zinc acetate and praseodymium acetate was 1:50. The mixture was held under negative pressure (0.01 standard atmospheres) for 2 h, and then the solid and liquid phases were separated. The solid phase was calcined at 450 °C for 3 h to obtain a coated powder. (3) Prepare an aqueous solution of lithium acetate, wherein the concentration of lithium acetate in the aqueous solution of lithium acetate is 25 g / 100 mL; immerse the coated powder in the aqueous solution of lithium acetate, wherein the ratio of the coated powder to the aqueous solution of lithium acetate is 1 g: 50 g; stir for 5 min, then filter, dry the solid phase at 100 °C for 10 min, calcine at 500 °C for 1 h after drying, then cool naturally to room temperature, and after cooling, immerse the powder in the aqueous solution of lithium acetate again according to the same process as above, stir for 5 min, filter, dry the solid phase at 100 °C for 10 min, but calcine at 500 °C for 5 h after drying to obtain the modified powder; (4) Barium feldspar powder, quartz powder, barium aluminum silicate powder, cerium oxide powder, the modified powder, and sodium tripolyphosphate are mixed evenly to obtain a mixed powder. The barium feldspar powder, quartz powder, barium aluminum silicate powder, cerium oxide powder, the modified powder, and sodium tripolyphosphate are in the following weight parts: 25 parts barium feldspar powder, 16 parts quartz powder, 7 parts barium aluminum silicate powder, 8 parts cerium oxide powder, 7 parts modified powder, and 2 parts sodium tripolyphosphate. Water is added to the mixed powder to adjust the moisture content to 10 wt%, and then it is pressed into a slab under a pressure of 40 MPa. The slab is dried at 80°C for 30 min, then calcined at 1150°C for 3 h, and then cooled in the furnace to obtain the ceramic plate described in this comparative example.

[0018] Comparative Example 2 A method for preparing a ceramic plate as a comparison includes the following steps: (1) Prepare a composite aqueous solution of cerium nitrate and manganese nitrate in a reactor. The concentration of cerium nitrate in the composite aqueous solution is 9 g / 100 mL, the concentration of manganese nitrate is 4 g / 100 mL, and the solvent is water. Ethylene glycol is added to the composite aqueous solution of cerium nitrate and manganese nitrate under stirring. After the addition is complete, stir for 10 min. Then, acetic acid and polyvinylpyrrolidone (K30) are added to the solution under stirring. After the addition is complete, stir for another 30 min. Then, seal the reactor, heat to 190℃ and keep at that temperature for 20 h, then allow it to cool naturally to room temperature. Open the reactor and add... Add sodium hydroxide solution to the composite aqueous solution of cerium nitrate and manganese nitrate. The ratio of ethylene glycol, acetic acid, polyvinylpyrrolidone, and sodium hydroxide solution is: composite aqueous solution of cerium nitrate and manganese nitrate: ethylene glycol: acetic acid: polyvinylpyrrolidone: sodium hydroxide solution = 10 mL: 24 mL: 0.9 mL: 0.7 g: 7 mL, wherein the mass percentage of solute in the sodium hydroxide solution is 20%. After the addition is completed, stir for 30 min, then separate the solid and liquid phases. Wash the solid phase three times with deionized water, dry it at 60 °C for 2 h, and then calcine it at 500–550 °C for 3 h to obtain composite oxide powder. (2) Prepare a composite aqueous solution of copper sulfate and ferrous sulfate, wherein the concentration of copper sulfate is 7 g / 100 mL, the concentration of ferrous sulfate is 11 g / 100 mL, and the solvent is water; prepare an ethanol solution of zinc acetate, wherein the concentration of zinc acetate is 21 g / L, and the solvent is ethanol; keep the composite aqueous solution of copper sulfate and ferrous sulfate at a constant temperature of 45°C in a water bath, and then add sodium carbonate solution to the solution while stirring, wherein the volume ratio of sodium carbonate solution added to the composite aqueous solution of copper sulfate and ferrous sulfate is [missing value] / [missing value]. Aqueous solution: Sodium carbonate solution = 10:4, wherein the concentration of sodium carbonate in the sodium carbonate solution is 20 g / 100 mL, and the solvent is water; after the addition is completed, stir at a constant temperature of 45 °C for 2 h, then separate the solid and liquid phases, wash the solid phase three times with deionized water, dry at 60 °C for 2 h, and soak the dried solid phase in the ethanol solution of zinc acetate to obtain a mixture, wherein the solid-liquid mass ratio of the dried solid phase soaked in the ethanol solution of zinc acetate is solid / liquid = 1:50; the mixture is held under negative pressure (0.01 standard atmospheres) for 2 h, then separate the solid and liquid phases, and calcine the solid phase at 450 °C for 3 h to obtain coated powder; (3) Prepare an aqueous solution of lithium acetate, wherein the concentration of lithium acetate in the aqueous solution of lithium acetate is 25 g / 100 mL; immerse the coated powder in the aqueous solution of lithium acetate, wherein the ratio of the coated powder to the aqueous solution of lithium acetate is 1 g: 50 g; stir for 5 min, then filter, dry the solid phase at 100 °C for 10 min, calcine at 500 °C for 1 h after drying, then cool naturally to room temperature, and after cooling, immerse the powder in the aqueous solution of lithium acetate again according to the same process as above, stir for 5 min, filter, dry the solid phase at 100 °C for 10 min, but calcine at 500 °C for 5 h after drying to obtain the modified powder; (4) Barium feldspar powder, quartz powder, barium aluminum silicate powder, the composite oxide powder, the modifying powder, and sodium tripolyphosphate are mixed evenly to obtain a mixed powder. The barium feldspar powder, quartz powder, barium aluminum silicate powder, the composite oxide powder, the modifying powder, and sodium tripolyphosphate are in the following weight parts: 25 parts barium feldspar powder, 16 parts quartz powder, 7 parts barium aluminum silicate powder, 8 parts composite oxide powder, 7 parts modifying powder, and 2 parts sodium tripolyphosphate. Water is added to the mixed powder to adjust the moisture content to 10 wt%, and then it is pressed into a slab under a pressure of 40 MPa. The slab is dried at 80°C for 30 min, then calcined at 1150°C for 3 h, and then cooled in the furnace to obtain the ceramic plate described in this comparative example.

[0019] Comparative Example 3 A method for preparing a ceramic plate as a comparison includes the following steps: (1) Prepare a composite aqueous solution of cerium nitrate and manganese nitrate in a reactor. The concentration of cerium nitrate in the composite aqueous solution is 9 g / 100 mL, the concentration of manganese nitrate is 4 g / 100 mL, and the solvent is water. Ethylene glycol is added to the composite aqueous solution of cerium nitrate and manganese nitrate under stirring. After the addition is complete, stir for 10 min. Then, acetic acid and polyvinylpyrrolidone (K30) are added to the solution under stirring. After the addition is complete, stir for another 30 min. Then, seal the reactor, heat to 190℃ and keep at that temperature for 20 h, then allow it to cool naturally to room temperature. Open the reactor and add... Add sodium hydroxide solution to the composite aqueous solution of cerium nitrate and manganese nitrate. The ratio of ethylene glycol, acetic acid, polyvinylpyrrolidone, and sodium hydroxide solution is: composite aqueous solution of cerium nitrate and manganese nitrate: ethylene glycol: acetic acid: polyvinylpyrrolidone: sodium hydroxide solution = 10 mL: 24 mL: 0.9 mL: 0.7 g: 7 mL, wherein the mass percentage of solute in the sodium hydroxide solution is 20%. After the addition is completed, stir for 30 min, then separate the solid and liquid phases. Wash the solid phase three times with deionized water, dry it at 60 °C for 2 h, and then calcine it at 500–550 °C for 3 h to obtain composite oxide powder. (2) Prepare a composite aqueous solution of copper sulfate and ferrous sulfate, wherein the concentration of copper sulfate is 7 g / 100 mL, the concentration of ferrous sulfate is 11 g / 100 mL, and the solvent is water; prepare a composite ethanol solution of zinc acetate and praseodymium acetate, wherein the concentration of zinc acetate is 21 g / L, the concentration of praseodymium acetate is 3 g / L, and the solvent is ethanol; keep the composite aqueous solution of copper sulfate and ferrous sulfate at a constant temperature of 45°C in a water bath, and then add sodium carbonate solution to the solution while stirring, wherein the volume ratio of sodium carbonate solution added to the composite aqueous solution of copper sulfate and ferrous sulfate is copper sulfate to ferrous sulfate. A composite aqueous solution of ferrous acetate and sodium carbonate solution was prepared at a ratio of 10:4, wherein the concentration of sodium carbonate in the sodium carbonate solution was 20 g / 100 mL, and the solvent was water. After the addition of the materials, the mixture was stirred at a constant temperature of 45 °C for 2 h, and then the solid and liquid phases were separated. The solid phase was washed three times with deionized water and dried at 60 °C for 2 h. The dried solid phase was then immersed in a composite ethanol solution of zinc acetate and praseodymium acetate to obtain a mixture. The solid-liquid mass ratio of the dried solid phase immersed in the composite ethanol solution of zinc acetate and praseodymium acetate was 1:50. The mixture was held under negative pressure (0.01 standard atmospheres) for 2 h, and then the solid and liquid phases were separated. The solid phase was calcined at 450 °C for 3 h to obtain a coated powder. (3) Barium feldspar powder, quartz powder, barium aluminum silicate powder, the composite oxide powder, the coating powder, and sodium tripolyphosphate are mixed evenly to obtain a mixed powder. The barium feldspar powder, quartz powder, barium aluminum silicate powder, the composite oxide powder, the coating powder, and sodium tripolyphosphate are in the following weight parts: 25 parts barium feldspar powder, 16 parts quartz powder, 7 parts barium aluminum silicate powder, 8 parts composite oxide powder, 7 parts coating powder, and 2 parts sodium tripolyphosphate. Water is added to the mixed powder to adjust the moisture content to 10 wt%, and then it is pressed into a slab under a pressure of 40 MPa. The slab is dried at 80°C for 30 min, then calcined at 1150°C for 3 h, and then cooled in the furnace to obtain the ceramic plate described in this comparative example.

[0020] Example 5 The infrared emissivity of the ceramic plates prepared by the methods described in the above embodiments and comparative examples was measured using an infrared spectrometer in the wavelength range of 8–14 μm. The flexural strength of the ceramic plates prepared by the methods described in the above embodiments and comparative examples was tested according to the requirements of standard GB / T 3810.4-2016. The sample size was cut to 40 mm × 20 mm × 5 mm, the test span was 36 mm, and the loading rate was 1 N / (mm²). 2 ·s). Test results are as follows Figure 1 and Figure 2 As shown.

[0021] Depend on Figure 1 and Figure 2It is evident that the ceramic slab prepared using the method described in this invention possesses excellent far-infrared emissivity and strength, improving the application performance of ceramic materials in decoration, heat insulation, and air purification, while also enhancing the durability of the ceramics. Comparing Example 3 of this invention with various comparative examples, it is clear that adding cerium-manganese composite oxide to the ceramic raw materials, employing a zinc-praseodymium coating process, or modifying with lithium oxide can all improve the far-infrared emissivity of the ceramic slab to a certain extent. Furthermore, the zinc-praseodymium coating process and the lithium oxide modification process can significantly improve the flexural strength of the ceramic. This may be because this invention first prepares cerium-manganese composite oxide and adds it to the ceramic. During the ceramic sintering process, cerium can induce the crystallization process, promote the occurrence of ceramic lattice distortion, and enhance the vibrational activity of the lattice. The addition of manganese and subsequent copper and iron elements helps to reduce lattice symmetry and enhance the anharmonic effect of lattice vibration, thereby improving the far-infrared emissivity of the ceramic. Subsequently, by coating with a zinc-praseodymium composite oxide, praseodymium ions are introduced into the ceramic crystal, introducing impurity energy levels into the crystal structure. This facilitates the escape of oxygen atoms from the lattice, forming oxygen vacancies, increasing electrons and holes, and promoting carrier absorption. Simultaneously, the presence of the radius difference between praseodymium ions and cerium / barium, along with the introduction of oxygen vacancies, further induces lattice distortion, thereby enhancing the effect of lattice vibrations on far-infrared radiation. Furthermore, praseodymium doping optimizes the surface state of the coated powder, providing better conditions for subsequent lithium modification. Finally, the lithium oxide modification process forms a lithium oxide layer, which promotes the sintering process of the ceramic. During sintering, it easily forms a composite phase with silicon dioxide, lowering the sintering temperature and significantly reducing internal microcrack defects, thus improving the strength of the ceramic material.

[0022] The technical solutions provided by the present invention have been described in detail above. For those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the embodiments of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for preparing a low-temperature sintered infrared porous ceramic plate, characterized in that the steps include... include: (1) Prepare a composite aqueous solution of cerium nitrate and manganese nitrate in a reaction vessel. Add ethylene glycol to the composite aqueous solution of cerium nitrate and manganese nitrate under stirring. After the addition is completed, stir for more than 10 minutes. Then, add acetic acid and polyvinylpyrrolidone to the solution under stirring. After the addition is completed, stir for more than 30 minutes. Then seal the reaction vessel and heat it to 180-190℃ and keep it at that temperature for more than 20 hours. Then, cool it naturally to room temperature. Open the reaction vessel and add sodium hydroxide solution. After the addition is completed, stir for more than 30 minutes. Then, separate the solid and liquid phases. Wash the solid phase with deionized water, dry it, and then calcine it at 500-550℃ for more than 3 hours to obtain composite oxide powder. (2) Prepare a composite aqueous solution of copper sulfate and ferrous sulfate, and a composite ethanol solution of zinc acetate and praseodymium acetate; keep the composite aqueous solution of copper sulfate and ferrous sulfate at a constant temperature of 45±5℃ in a water bath, and then add sodium carbonate solution to the solution under stirring. After the addition is completed, continue stirring at a constant temperature of 45±5℃ for more than 2 hours. Then, separate the solid and liquid phases, wash the solid phase with deionized water, dry it, and soak the dried solid phase in the composite ethanol solution of zinc acetate and praseodymium acetate to obtain a mixture. Keep the mixture under negative pressure for more than 2 hours, and then separate the solid and liquid phases. Calcine the solid phase at 400~450℃ for more than 3 hours to obtain coated powder. (3) Prepare an aqueous solution of lithium acetate, immerse the coated powder in the aqueous solution of lithium acetate, stir for more than 5 minutes, then filter, dry in solid phase, calcine at 500-550°C for more than 1 hour after drying, then cool naturally to room temperature, immerse again in the aqueous solution of lithium acetate, stir for more than 5 minutes, filter, dry in solid phase, calcine at 500-550°C for more than 5 hours after drying to obtain the modified powder; (4) Mix barium feldspar powder, quartz powder, barium aluminum silicate powder, the composite oxide powder, the modified powder, and sodium tripolyphosphate evenly to obtain a mixed powder. Add water to the mixed powder to adjust the moisture content, then press it into a slab. The slab is dried and then calcined at 1140-1160°C and then cooled in the furnace to obtain the infrared porous ceramic plate.

2. The method for preparing a low-temperature sintered infrared porous ceramic plate according to claim 1, characterized in that, In step (1), the concentration of cerium nitrate in the composite aqueous solution of cerium nitrate and manganese nitrate is 8-10 g / 100 mL, the concentration of manganese nitrate is 3-4 g / 100 mL, and the solvent is water. The ratio of ethylene glycol, acetic acid, polyvinylpyrrolidone, and sodium hydroxide solution added to the composite aqueous solution of cerium nitrate and manganese nitrate is: composite aqueous solution of cerium nitrate and manganese nitrate: ethylene glycol: acetic acid: polyvinylpyrrolidone: sodium hydroxide solution = 10 mL: 20-25 mL: 0.8-1 mL: 0.5-0.8 g: 5-8 mL, wherein the mass percentage of solute in the sodium hydroxide solution is 20%-25%.

3. The method for preparing a low-temperature sintered infrared porous ceramic plate according to claim 1, characterized in that, In step (2), the concentration of copper sulfate in the composite aqueous solution of copper sulfate and ferrous sulfate is 5-8 g / 100 mL, the concentration of ferrous sulfate is 10-12 g / 100 mL, and the solvent is water; the concentration of zinc acetate in the composite ethanol solution of zinc acetate and praseodymium acetate is 20-22 g / L, the concentration of praseodymium acetate is 2-4 g / L, and the solvent is ethanol.

4. The method for preparing a low-temperature sintered infrared porous ceramic plate according to claim 3, characterized in that, In step (2), the volume ratio of sodium carbonate solution added to the composite aqueous solution of copper sulfate and ferrous sulfate is 10:3-5, the concentration of sodium carbonate in the sodium carbonate solution is 18-20 g / 100 mL, and the solvent is water.

5. The method for preparing a low-temperature sintered infrared porous ceramic plate according to claim 3, characterized in that, In step (2), the solid phase after drying is immersed in the composite ethanol solution of zinc acetate and praseodymium acetate with a solid-liquid mass ratio of 1:50 to 200.

6. The method for preparing a low-temperature sintered infrared porous ceramic plate according to claim 1, characterized in that, In step (3), the concentration of lithium acetate in the aqueous solution of lithium acetate is 22-25 g / 100 mL; the ratio of the amount of coating powder soaked in the aqueous solution of lithium acetate is 1 g of coating powder to 50-100 g of aqueous solution of lithium acetate.

7. The method for preparing a low-temperature sintered infrared porous ceramic plate according to claim 1, characterized in that, In step (4), the barium feldspar powder, quartz powder, barium aluminum silicate powder, composite oxide powder, modifying powder, and sodium tripolyphosphate are in the following weight proportions: 25 parts barium feldspar powder, 12-18 parts quartz powder, 6-8 parts barium aluminum silicate powder, 3-10 parts composite oxide powder, 5-8 parts modifying powder, and 1.8-2.2 parts sodium tripolyphosphate.

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