Preparation method of porous ceramic material with oxygen permeability and far infrared catalytic function and application thereof in brewing

Abstract

This invention relates to the technical field of porous ceramic materials, and discloses a method for preparing porous ceramic materials with oxygen permeability and far-infrared catalytic functions and their application in brewing. The method includes the following steps: (1) mixing modified diatomaceous earth with nano-Fe2O3, nano-TiO2, and nano-CeO2 to obtain a first mixture; mixing quartz of different particle sizes and waste porcelain powder to obtain a second mixture; (2) mixing the first mixture, the second mixture, clay, and potassium feldspar, and then wet-milling to obtain a slurry; (3) filtering the slurry, then vacuum-processing and aging it to obtain a mud section; (4) rolling and drying the mud section to obtain a green body; (5) glazing one side of the inner side of the green body; (6) firing at high temperature, then spraying nano-silica sol and sintering. The porous ceramic material obtained by this invention can achieve controllable oxygen permeability without liquid leakage and far-infrared synergistic catalysis, thereby accelerating the aging and esterification reactions of the wine.

Description

Technical Field

[0001] This invention belongs to the technical field of porous ceramic materials, and more specifically relates to a method for preparing a porous ceramic material with oxygen permeability and far-infrared catalytic function and its application in brewing. Background Technology

[0002] In the winemaking industry, the wine vat, as an important brewing container, has a crucial impact on the quality of the wine. Traditional wine vats have certain functional limitations and cannot meet the demands of modern winemaking processes to improve wine quality and shorten the brewing cycle.

[0003] On the one hand, traditional wine vats have poor oxygen permeability. During the winemaking process, adequate oxygen contact plays a crucial role in the aging and esterification reactions of the wine. However, ordinary wine vats often fail to provide adequate aeration and oxygen permeability, resulting in slow fermentation and difficulty in achieving the desired flavor and taste. Some wine vats, in an effort to prevent leakage, employ overly tight seals, further hindering oxygen entry and limiting the improvement of wine quality.

[0004] On the other hand, traditional wine vats lack effective mechanisms to promote the aging and esterification reactions of the wine. Although the fermentation process of wine mainly relies on the action of microorganisms, suitable external conditions can accelerate this process. Most wine vats currently on the market do not consider using special materials or structures to accelerate the chemical reactions of the wine, resulting in a longer brewing cycle and higher production costs.

[0005] Furthermore, with increasing public concern about food safety and health, the safety of wine vats has become a significant issue. Traditional wine vats may pose a risk of heavy metal migration, such as lead and cadmium, which could threaten human health. Therefore, developing a safe and reliable wine vat with good oxygen permeability that can accelerate the aging and esterification reactions of wine is of great practical importance. Summary of the Invention

[0006] The main objective of this invention is to address the aforementioned problems by providing a method for preparing porous ceramic materials with oxygen permeability and far-infrared catalytic functions, and their application in brewing. By compounding quartz, waste porcelain powder, and diatomaceous earth of different particle sizes, a gradient distribution of micro- and nanopores is formed after sintering, achieving controllable oxygen permeability without liquid leakage. The introduction of the Fe2O3-TiO2-CeO2 nanosystem enables far-infrared synergistic catalysis, thereby obtaining a porous ceramic material with oxygen permeability and far-infrared catalytic functions.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0008] One of the technical solutions of the present invention: a method for preparing a porous ceramic material with oxygen permeability and far-infrared catalytic function, comprising the following steps:

[0009] (1) Modified diatomaceous earth is mixed with nano Fe2O3, nano TiO2 and nano CeO2 to obtain the first mixture; quartz of different particle sizes and waste porcelain powder are mixed to obtain the second mixture;

[0010] (2) The first mixture, the second mixture, clay and potassium feldspar are mixed and then wet-milled to obtain a slurry; by mass percentage, the slurry includes 5-10% modified diatomaceous earth, 4-6% nano Fe2O3, 3-4% nano TiO2, 0.5-1% nano CeO2, 15-25% quartz, 5-10% waste porcelain powder, 40-50% clay and 10-15% potassium feldspar;

[0011] (3) After the mud is pressed and filtered, it is then vacuum-kneaded and aged to obtain mud segments;

[0012] (4) After rolling and drying the clay sections, a green body is obtained;

[0013] (5) After mixing potassium feldspar, quartz, kaolin, calcite, barium carbonate and zinc oxide, water is added and stirred to obtain glaze; by mass percentage, the glaze includes 35-45% potassium feldspar, 20-30% quartz, 5-10% kaolin, 15-20% calcite, 1-5% barium carbonate and 3-8% zinc oxide; the inner side of the green body is glazed by pouring glaze.

[0014] (6) After the glazed body is fired at high temperature, nano-silica sol is sprayed and sintered to obtain porous ceramic material.

[0015] This invention utilizes a blend of quartz and waste ceramic powder of varying particle sizes, combined with the inherent porous structure of diatomaceous earth, to create a gradient distribution of micro- and nanopores after sintering. This allows for controlled oxygen permeability without liquid leakage. The introduction of an Fe2O3-TiO2-CeO2 nanosystem enables far-infrared synergistic catalysis, and the modified diatomaceous earth adsorbs this Fe2O3-TiO2-CeO2 nanosystem, improving its dispersibility and uniformity, further enhancing the infrared synergistic effect.

[0016] However, diatomaceous earth is prone to significant volume changes during firing, affecting its mechanical strength. Pre-firing diatomaceous earth decomposes organic matter in advance, improving structural stability. Without pre-firing, the gases generated by residual organic matter in the diatomaceous earth during high-temperature firing will break through the glaze layer, leading to uneven cracks or bubbles. Furthermore, pre-firing promotes the transformation of quartz in diatomaceous earth and eliminates stress.

[0017] By adjusting the components of their respective raw materials, the coefficient of thermal expansion of the body is made slightly greater than that of the glaze (the coefficient of thermal expansion of the glaze is 0.5-1.0 × 10⁻⁶ higher than that of the body). -6During the cooling process, the glaze shrinks faster, causing tensile stress. When this stress exceeds the tensile strength of the glaze, it cracks, forming uniform, fine network cracks while maintaining good interfacial adhesion. Furthermore, by controlling the micro-nano porous structure in the green body, the micro-nano porous structure on the surface of the body can be effectively connected to the air-permeable channels (crazing cracks or micropores) in the glaze, further achieving oxygen permeability while preventing liquid penetration. Finally, a silica sol nanofilm is used to seal the micropores on the glaze surface. The nanoparticles form a "fence" at the crack opening, ensuring both oxygen permeability and liquid impermeability, while surface passivation achieves long-term impermeability.

[0018] More preferably, in step (1), the modified diatomaceous earth is obtained by pre-calcining diatomaceous earth at 700-800℃ for 120-150 min and then modifying it by coating it with nano-alumina sol.

[0019] Adding diatomaceous earth reduces the coefficient of thermal expansion of the body, resulting in an excessive difference in the coefficient of thermal expansion between the body and the glaze layer. This leads to excessively large cracks that affect the material strength and make it prone to leakage. Therefore, by adding nano-alumina sol coating modification, the coefficient of thermal expansion can be balanced, and the volume change of diatomaceous earth can be reduced. High-temperature firing inhibits densification and preserves the porous structure.

[0020] More preferably, the density of the diatomaceous earth is 2.0-2.3 g / cm³. 3 The porosity is 80-90%, the pore size is 50-3000nm, and the particle size is 1-50μm; the coating modification amount of the nano alumina sol is 10-20% of the mass of diatomaceous earth, the solid content of the nano alumina sol is 20-25%, and the particle size of the nano alumina is 10-20nm.

[0021] After preliminary calcination, diatomaceous earth can further form a connected porous structure, and the preliminary calcination process helps to improve the structural stability of diatomaceous earth in the green body and avoid large volume changes during high-temperature firing.

[0022] More preferably, the quartz comprises coarse-grained quartz and fine-grained quartz in a mass ratio of 2-3:1, with the coarse-grained quartz having a particle size of 150-200 μm and the fine-grained quartz having a particle size of 20-50 μm; the waste ceramic powder has a particle size of 40-80 μm; and the nano-Fe2O3, nano-TiO2, and nano-CeO2 have a particle size of 20-100 nm.

[0023] Using waste ceramic powder as raw material reduces costs and improves sintering stability. The particle size of the waste ceramic powder, combined with that of quartz, helps form a gradient distribution of micro- and nanopores. The particle sizes of nano-Fe2O3, nano-TiO2, and nano-CeO2 are beneficial for filling gaps and are compatible with the porous structure of diatomaceous earth, achieving adsorption to improve the loading stability of the Fe2O3-TiO2-CeO2 nanosystem in ceramic materials. Furthermore, it exhibits higher dispersibility and uniformity, enhancing synergistic far-infrared performance.

[0024] More preferably, in step (3), the moisture content of the mud cake obtained after pressure filtration is 19-25%; and the aging time is 24-36h.

[0025] More preferably, in step (5), the glaze is obtained by passing it through a 300-325 mesh sieve with a residue of 0.05%; the solid content of the glaze is 50-55%. The thickness of the glaze is 0.3-0.5 mm.

[0026] After sieving, the glaze is obtained to prevent particles from clogging the pores of the body. The solid content of the glaze is controlled to ensure fluidity and glaze thickness. The glaze thickness can ensure that the micro-nano pore structure on the surface of the body is effectively connected with the air-permeable channels in the glaze layer, achieving oxygen permeability but liquid impermeability, and ensuring the strength of the glaze surface.

[0027] More preferably, in step (6), the high-temperature firing process is as follows: the temperature is raised to 1200~1280℃, the heating rate is 40-60℃ / h, and the holding time is 5-10h; after high-temperature firing, the temperature is lowered to 700-800℃ at a cooling rate of 20-30℃ / h, and then naturally cooled to room temperature and placed in an oxygen kiln for 24h or more.

[0028] More preferably, in step (6), the solid content of the nano silica sol is 5-6%, and the particle size of the nano SiO2 is 10-20nm; the spraying of nano silica sol and sintering is as follows: the blank after high temperature firing and cooling is preheated to 60-80℃, the nano silica sol is sprayed, and then the temperature is raised to 150-200℃ for sintering, and the temperature is held for 20-30min; after sintering, the thickness of the obtained silica film is 0.5-2μm.

[0029] A silica sol nanofilm is used to seal the micropores of the glaze surface. The sealing is achieved by controlling the concentration, particle size, and thickness of the silica sol, but it only blocks liquids, allowing gas diffusion. If the particle size is too small, it easily blocks deep channels; if the particle size is too large, the bonding is weak and the film strength is low. If the thickness is too thin, the sealing is incomplete, leading to slow liquid leakage; if the thickness is too thick, it loses permeability and the film layer is prone to peeling off, causing localized leakage.

[0030] The second technical solution of the present invention: the application of a porous ceramic material in brewing.

[0031] Porous ceramic materials are used to make wine tanks for brewing. Through the design of multi-level pore structure and the compounding of far-infrared catalytic components, the wine can be matured efficiently, the aging and esterification reactions can be accelerated, the taste and quality of the wine can be improved, and the wine can be safe.

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] (1) Multi-level pore structure design: By compounding raw materials (quartz + waste porcelain powder + diatomite) with different particle sizes, a gradient distribution of micro and nano pores is formed to achieve controllable oxygen permeability without liquid leakage;

[0034] (2) Far-infrared synergistic catalysis: The Fe2O3-TiO2-CeO2 nano system is introduced to provide efficient radiation in the 8-14μm band, which accelerates the vibration of wine molecules and esterification reaction.

[0035] (3) Recycling of waste porcelain: Waste porcelain powder is used as raw material to reduce costs and improve sintering stability. Detailed Implementation

[0036] The following examples further illustrate the above-described content of the present invention, but it should not be construed as limiting the scope of the subject matter of the present invention to the following examples. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention.

[0037] The raw materials used in the examples and comparative examples are as follows:

[0038] Diatomaceous earth: density 2.0-2.3 g / cm³ 3 The porosity is 80-90%, the particle size is 1-50μm, the average particle size is 20μm, and the pore size is 50-3000nm;

[0039] Nano alumina sol: solid content is 20-25%, nano alumina particle size is 10-20nm, and average particle size is 14nm;

[0040] Quartz (quartz added to the mud): coarse-grained quartz has a particle size of 150-200μm and an average particle size of 180μm; fine-grained quartz has a particle size of 20-50μm and an average particle size of 26μm.

[0041] Potassium feldspar (potassium feldspar added to the mud): Potassium feldspar powder of grades 1-7 can be selected, with an average particle size ≤40μm;

[0042] Waste ceramic powder: particle size 40-80μm, average particle size 50μm;

[0043] Nano Fe2O3: Particle size 20-100nm, average particle size 50nm;

[0044] Nano TiO2: Anatase type, with a particle size of 20-100nm and an average particle size of 50nm;

[0045] Nano CeO2: Particle size 20-100nm, average particle size 50nm;

[0046] Nano silica sol: solid content is 5-6%, nano SiO2 particle size is 10-20nm, and average particle size is 16nm;

[0047] Other raw materials (including potassium feldspar, quartz, kaolin, calcite, barium carbonate and zinc oxide used in the glaze) all use the specifications and dimensions commonly used in the field.

[0048] Example 1

[0049] By mass percentage, the mud consists of 7% modified diatomite, 35% nano-Fe2O, 3.5% nano-TiO2, 0.5% nano-CeO2, 18% quartz (8% coarse-grained quartz and 10% fine-grained quartz), 7% waste porcelain powder, 45% clay, and 14% potassium feldspar.

[0050] By weight percentage, the glaze comprises 41% potassium feldspar, 25% quartz, 8% kaolin, 16% calcite, 3% barium carbonate, and 7% zinc oxide.

[0051] The preparation method of porous ceramic wine jars specifically includes the following steps:

[0052] (1) Diatomaceous earth was heated to 750℃ at 10℃ / min and pre-calcined at 750℃ for 140 min. After cooling, nano alumina sol was added and ball-milled for 25 min to obtain modified diatomaceous earth. The amount of nano alumina sol coating modification was 15% of the mass of diatomaceous earth.

[0053] (2) Mix the modified diatomaceous earth with nano Fe2O3, nano TiO2 and nano CeO2 evenly to obtain the first mixture; mix quartz of different particle sizes and waste porcelain powder evenly to obtain the second mixture;

[0054] (3) After mixing the first mixture, the second mixture, clay and potassium feldspar, wet ball milling is performed to obtain a slurry with a particle size of 50-70 mesh;

[0055] (4) After the mud slurry is filtered, the moisture content of the mud cake is 22%. After vacuum kneading and aging for 24 hours, mud segments are obtained.

[0056] (5) After rolling and drying the clay sections, a green body is obtained;

[0057] (6) After mixing potassium feldspar, quartz, kaolin, calcite, barium carbonate and zinc oxide, add water and mix and stir. Wet grind for 7 hours, and pass through a 325 mesh sieve with 0.05% residue to obtain a glaze with a solid content of 50%. Apply glaze to the inner side of the green body using the glazing method, and the thickness of the glaze is 0.36±0.02mm.

[0058] (7) The glazed body is fired at high temperature, heated to 1220℃, with a heating rate of 50℃ / h and a holding time of 8h; after high temperature firing, it is cooled to 800℃ at a cooling rate of 25℃ / h, then naturally cooled to room temperature, and placed in an oxygen kiln for 36h to obtain a porous ceramic wine jar (glaze on the inside).

[0059] Example 2

[0060] The preparation steps in this embodiment are the same as those in Example 1, except that: the porous ceramic wine jar obtained in Example 1 is preheated to 70°C, nano-silica sol is sprayed on the glaze surface, the temperature is raised to 200°C, and the temperature is held for 20 minutes. After sintering, the thickness of the silica film layer is 1.5±0.1μm, thus obtaining the porous ceramic wine jar in this embodiment.

[0061] Example 3

[0062] By mass percentage, the mud consists of 9% modified diatomaceous earth, 4% nano-Fe2O3, 3% nano-TiO2, 0.5% nano-CeO2, 22% quartz (8% coarse-grained quartz and 14% fine-grained quartz), 6% waste porcelain powder, 43.5% clay, and 12% potassium feldspar.

[0063] By weight percentage, the glaze comprises 38% potassium feldspar, 27% quartz, 10% kaolin, 16% calcite, 3% barium carbonate, and 6% zinc oxide.

[0064] The preparation method of porous ceramic wine jars specifically includes the following steps:

[0065] (1) Diatomaceous earth was heated to 750℃ at 10℃ / min and pre-calcined at 750℃ for 140 min. After cooling, nano alumina sol was added and ball-milled for 25 min to obtain modified diatomaceous earth. The amount of nano alumina sol coating modification was 15% of the mass of diatomaceous earth.

[0066] (2) Mix the modified diatomaceous earth with nano Fe2O3, nano TiO2 and nano CeO2 evenly to obtain the first mixture; mix quartz of different particle sizes and waste porcelain powder evenly to obtain the second mixture;

[0067] (3) After mixing the first mixture, the second mixture, clay and potassium feldspar, wet ball milling is performed to obtain a slurry with a particle size of 50-70 mesh;

[0068] (4) After the mud slurry is filtered, the moisture content of the mud cake is 21%. After vacuum kneading and aging for 24 hours, mud segments are obtained.

[0069] (5) After rolling and drying the clay sections, a green body is obtained;

[0070] (6) After mixing potassium feldspar, quartz, kaolin, calcite, barium carbonate and zinc oxide, add water and stir, wet grind for 7 hours, and pass through a 325 mesh sieve with 0.05% residue to obtain a glaze with a solid content of 50%; apply glaze to the inner side of the green body by pouring glaze, and the thickness of the glaze is 0.42±0.02mm.

[0071] (7) The glazed body is fired at high temperature, heated to 1220℃ at a rate of 50℃ / h and held for 8h. After high temperature firing, the body is cooled to 800℃ at a rate of 25℃ / h and then cooled naturally to room temperature and placed in an oxygen kiln for 36h. Then it is preheated to 70℃, nano silica sol is sprayed on the glaze surface, heated to 200℃ and held for 20min. The thickness of the silica film obtained after sintering is 1.1±0.1μm, and a porous ceramic wine jar (glaze surface on the inside) is obtained.

[0072] Example 4

[0073] By mass percentage, the mud consists of 7% modified diatomite, 35% nano-Fe2O, 3.5% nano-TiO2, 0.5% nano-CeO2, 18% quartz (8% coarse-grained quartz and 10% fine-grained quartz), 7% waste porcelain powder, 45% clay, and 14% potassium feldspar.

[0074] By weight percentage, the glaze comprises 41% potassium feldspar, 25% quartz, 8% kaolin, 16% calcite, 3% barium carbonate, and 7% zinc oxide.

[0075] The preparation method of porous ceramic wine jars specifically includes the following steps:

[0076] (1) Diatomaceous earth was heated to 800℃ at 10℃ / min and pre-calcined at 800℃ for 120 min. After cooling, nano alumina sol was added and ball-milled for 30 min to obtain modified diatomaceous earth. The amount of coating modification by nano alumina sol was 18% of the mass of diatomaceous earth.

[0077] (2) Mix the modified diatomaceous earth with nano Fe2O3, nano TiO2 and nano CeO2 evenly to obtain the first mixture; mix quartz of different particle sizes and waste porcelain powder evenly to obtain the second mixture;

[0078] (3) After mixing the first mixture, the second mixture, clay and potassium feldspar, wet ball milling is performed to obtain a slurry with a particle size of 50-70 mesh;

[0079] (4) After the mud slurry is filtered, the mud cake has a moisture content of 24%. After vacuum kneading and aging for 24 hours, mud segments are obtained.

[0080] (5) After rolling and drying the clay sections, a green body is obtained;

[0081] (6) After mixing potassium feldspar, quartz, kaolin, calcite, barium carbonate and zinc oxide, add water and mix and stir. Wet grind for 7 hours, and pass through a 325 mesh sieve with 0.05% residue to obtain a glaze with a solid content of 50%. Apply glaze to the inner side of the green body using the glazing method, and the thickness of the glaze is 0.36±0.02mm.

[0082] (7) The glazed body is fired at high temperature, heated to 1220℃ at a rate of 50℃ / h and held for 8h. After high temperature firing, the body is cooled to 800℃ at a rate of 25℃ / h and then cooled naturally to room temperature and placed in an oxygen kiln for 36h. Then it is preheated to 70℃, nano silica sol is sprayed on the glaze surface, heated to 200℃ and held for 20min. The thickness of the silica film obtained after sintering is 1.5±0.1μm, and a porous ceramic wine jar (glaze surface on the inside) is obtained.

[0083] Comparative Example 1

[0084] This comparative example uses the same steps as Example 2 to prepare a porous ceramic wine jar, the only difference being that 18% fine-grained quartz is added.

[0085] Comparative Example 2

[0086] This comparative example uses the same steps as Example 2 to prepare porous ceramic wine jars, the only difference being that no modified diatomaceous earth was added.

[0087] By mass percentage, the mud comprises 35% nano-Fe2O, 3.5% nano-TiO2, 0.5% nano-CeO2, 20% quartz (10% coarse-grained quartz and 10% fine-grained quartz), 9% waste porcelain powder, 47% clay, and 15% potassium feldspar.

[0088] By weight percentage, the glaze comprises 41% potassium feldspar, 25% quartz, 8% kaolin, 16% calcite, 3% barium carbonate, and 7% zinc oxide.

[0089] The preparation method of porous ceramic wine jars specifically includes the following steps:

[0090] (1) Mix nano Fe2O3, nano TiO2 and nano CeO2 evenly to obtain the first mixture; mix quartz of different particle sizes and waste ceramic powder evenly to obtain the second mixture;

[0091] (2) After mixing the first mixture, the second mixture, clay and potassium feldspar, wet ball milling is performed to obtain a slurry with a particle size of 50-70 mesh;

[0092] (3) After the mud slurry is filtered, the mud cake has a moisture content of 22%. After vacuum kneading and aging for 24 hours, mud segments are obtained.

[0093] (4) After rolling and drying the clay sections, a green body is obtained;

[0094] (5) After mixing potassium feldspar, quartz, kaolin, calcite, barium carbonate and zinc oxide, add water and mix and stir. Wet grind for 7 hours, and pass through a 325 mesh sieve with 0.05% residue to obtain a glaze with a solid content of 50%. Apply glaze to the inner side of the green body using the glazing method, and the thickness of the glaze is 0.36±0.02mm.

[0095] (6) The glazed body is fired at high temperature, heated to 1220℃ at a rate of 50℃ / h and held for 8h. After high temperature firing, the body is cooled to 800℃ at a rate of 25℃ / h and then cooled naturally to room temperature and placed in an oxygen kiln for 36h. Then it is preheated to 70℃, nano silica sol is sprayed on the glaze surface, heated to 200℃ and held for 20min. The thickness of the silica film obtained after sintering is 1.5±0.1μm, and a porous ceramic wine jar (glaze surface on the inside) is obtained.

[0096] Comparative Example 3

[0097] This comparative example uses the same steps as Example 2 to prepare porous ceramic wine jars, the only difference being that the modified diatomaceous earth was not modified by alumina sol coating.

[0098] The preparation method of porous ceramic wine jars specifically includes the following steps:

[0099] (1) The diatomaceous earth was heated to 750℃ at 10℃ / min and pre-calcined at 750℃ for 140 min, and then cooled to obtain modified diatomaceous earth;

[0100] (2) Mix the modified diatomaceous earth with nano Fe2O3, nano TiO2 and nano CeO2 evenly to obtain the first mixture; mix quartz of different particle sizes and waste porcelain powder evenly to obtain the second mixture;

[0101] (3) After mixing the first mixture, the second mixture, clay and potassium feldspar, wet ball milling is performed to obtain a slurry with a particle size of 50-70 mesh;

[0102] (4) After the mud slurry is filtered, the moisture content of the mud cake is 22%. After vacuum kneading and aging for 24 hours, mud segments are obtained.

[0103] (5) After rolling and drying the clay sections, a green body is obtained;

[0104] (6) After mixing potassium feldspar, quartz, kaolin, calcite, barium carbonate and zinc oxide, add water and mix and stir. Wet grind for 7 hours, and pass through a 325 mesh sieve with 0.05% residue to obtain a glaze with a solid content of 50%. Apply glaze to the inner side of the green body using the glazing method, and the thickness of the glaze is 0.36±0.02mm.

[0105] (7) The glazed body is fired at high temperature, heated to 1220℃ at a rate of 50℃ / h and held for 8h. After high temperature firing, the body is cooled to 800℃ at a rate of 25℃ / h and then cooled naturally to room temperature and placed in an oxygen kiln for 36h. Then it is preheated to 70℃, nano silica sol is sprayed on the glaze surface, heated to 200℃ and held for 20min. The thickness of the silica film obtained after sintering is 1.5±0.1μm, and a porous ceramic wine jar (glaze surface on the inside) is obtained.

[0106] Comparative Example 4

[0107] This comparative example uses the same steps as Example 2 to prepare porous ceramic wine jars, the only difference being that the diatomaceous earth was not pre-fired sufficiently.

[0108] The preparation method of porous ceramic wine jars specifically includes the following steps:

[0109] (1) The diatomaceous earth was heated to 550℃ at 10℃ / min and pre-calcined at 550℃ for 70 min. After cooling, nano alumina sol was added and ball-milled for 25 min to obtain modified diatomaceous earth. The amount of nano alumina sol coating modification was 15% of the mass of diatomaceous earth.

[0110] (2) Mix the modified diatomaceous earth with nano Fe2O3, nano TiO2 and nano CeO2 evenly to obtain the first mixture; mix quartz of different particle sizes and waste porcelain powder evenly to obtain the second mixture;

[0111] (3) After mixing the first mixture, the second mixture, clay and potassium feldspar, wet ball milling is performed to obtain a slurry with a particle size of 50-70 mesh;

[0112] (4) After the mud slurry is filtered, the moisture content of the mud cake is 22%. After vacuum kneading and aging for 24 hours, mud segments are obtained.

[0113] (5) After rolling and drying the clay sections, a green body is obtained;

[0114] (6) After mixing potassium feldspar, quartz, kaolin, calcite, barium carbonate and zinc oxide, add water and mix and stir. Wet grind for 7 hours, and pass through a 325 mesh sieve with 0.05% residue to obtain a glaze with a solid content of 50%. Apply glaze to the inner side of the green body using the glazing method, and the thickness of the glaze is 0.36±0.02mm.

[0115] (7) The glazed body is fired at high temperature, heated to 1220℃ at a rate of 50℃ / h and held for 8h. After high temperature firing, the body is cooled to 800℃ at a rate of 25℃ / h and then cooled naturally to room temperature and placed in an oxygen kiln for 36h. Then it is preheated to 70℃, nano silica sol is sprayed on the glaze surface, heated to 200℃ and held for 20min. The thickness of the silica film obtained after sintering is 1.5±0.1μm, and a porous ceramic wine jar (glaze surface on the inside) is obtained.

[0116] Comparative Example 5

[0117] This comparative example uses the same steps as Example 2 to prepare a porous ceramic wine jar, the only difference being that the nano-silica sol has a larger particle size and a thicker thickness.

[0118] The preparation method of porous ceramic wine jars specifically includes the following steps:

[0119] (1) Diatomaceous earth was heated to 750℃ at 10℃ / min and pre-calcined at 750℃ for 140 min. After cooling, nano alumina sol was added and ball-milled for 25 min to obtain modified diatomaceous earth. The amount of nano alumina sol coating modification was 15% of the mass of diatomaceous earth.

[0120] (2) Mix the modified diatomaceous earth with nano Fe2O3, nano TiO2 and nano CeO2 evenly to obtain the first mixture; mix quartz of different particle sizes and waste porcelain powder evenly to obtain the second mixture;

[0121] (3) After mixing the first mixture, the second mixture, clay and potassium feldspar, wet ball milling is performed to obtain a slurry with a particle size of 50-70 mesh;

[0122] (4) After the mud slurry is filtered, the moisture content of the mud cake is 22%. After vacuum kneading and aging for 24 hours, mud segments are obtained.

[0123] (5) After rolling and drying the clay sections, a green body is obtained;

[0124] (6) After mixing potassium feldspar, quartz, kaolin, calcite, barium carbonate and zinc oxide, add water and mix and stir. Wet grind for 7 hours, and pass through a 325 mesh sieve with 0.05% residue to obtain a glaze with a solid content of 50%. Apply glaze to the inner side of the green body using the glazing method, and the thickness of the glaze is 0.36±0.02mm.

[0125] (7) The glazed body is fired at high temperature, heated to 1220℃ at a rate of 50℃ / h and held for 8h. After high temperature firing, the body is cooled to 800℃ at a rate of 25℃ / h and then naturally cooled to room temperature and placed in an oxygen kiln for 36h. Then it is preheated to 70℃ and nano silica sol (mass concentration of 5%, average particle size of nano SiO2 of 28nm, particle size range of 20-30nm) is sprayed on the glaze surface. The temperature is raised to 200℃ and held for 20min. The thickness of the silica film obtained after sintering is 3.0±0.1μm, and a porous ceramic wine jar (glaze on the inside) is obtained.

[0126] Table 1

[0127]

[0128] Note: Far-infrared emissivity: 8~14μm band, calculated by FTIR integration.

[0129] Table 2

[0130]

[0131] Note: Ordinary ceramic wine jars are commercially available; specifically, they are wine jars with excellent sealing properties and no air or oxygen permeability.

[0132] As shown in Table 1, the porous ceramic wine jars prepared in Examples 2-4 of this invention have good oxygen permeability, can accelerate the aging and esterification reactions of the wine, and have lead migration ≤0.1mg / L and cadmium migration ≤0.01mg / L, thus they are safe and reliable.

[0133] In Example 1, no silica sol nanofilm was used, and the resulting wine tank was prone to leakage after long-term storage. However, in Example 2, which used silica sol nanofilm, although the oxygen permeability of the wine tank was slightly reduced, the water absorption rate was also reduced. Moreover, after long-term storage, the percentage increase in ethyl acetate and ethyl hexanoate content in the wine was comparable to that in Example 1, and there was no leakage.

[0134] In Comparative Example 1, only a single fine-grained quartz was used to prepare the wine vat. The body failed to form a good gradient porous structure, and the micro-nano pores on the surface of the body could not effectively connect with the air-permeable channels in the glaze, resulting in reduced oxygen permeability. In Comparative Example 2, no modified diatomaceous earth was added during body preparation. Besides affecting the formation of the gradient porous structure, this also resulted in the thermal expansion coefficients of the body and the glaze being too close, preventing the formation of crazing cracks and thus making the oxygen permeability almost zero. Furthermore, the lack of modified diatomaceous earth also affected the distribution of the Fe2O3-TiO2-CeO2 nanosystem, failing to demonstrate a good infrared synergistic effect. In Comparative Example 3, the added modified diatomaceous earth was not coated with alumina sol, leading to an excessively large thermal expansion coefficient of the glaze relative to the body, resulting in larger crazing cracks. While this improved oxygen permeability, it also posed a risk of leakage and affected the strength of the wine vat. In Comparative Example 4, the diatomaceous earth was not sufficiently roasted. The residual organic matter in the diatomaceous earth, when subjected to high-temperature firing, caused gases to break through the glaze layer, resulting in uneven cracks or bubbles. Consequently, the resulting wine vat was weak and prone to leakage. After holding liquor in the vat for a period of time, it could not withstand the pressure and broke, making it impossible to conduct relevant tests after 6 months of storage. In Comparative Example 5, the silica sol particles were too large, resulting in weak bonding. An excessively thick film layer was more prone to peeling, leading to localized leakage.

[0135] Unless otherwise specified, the raw materials and equipment used in this invention are all commonly used in the field; unless otherwise specified, the methods used in this invention are all conventional methods in the field.

[0136] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, alterations, and equivalent transformations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing a porous ceramic material with oxygen permeability and far-infrared catalytic function, characterized in that, Includes the following steps: (1) Modified diatomaceous earth is mixed with nano Fe2O3, nano TiO2 and nano CeO2 to obtain the first mixture; quartz of different particle sizes and waste porcelain powder are mixed to obtain the second mixture; The modified diatomaceous earth is obtained by pre-calcining diatomaceous earth at 700-800℃ for 120-150 min, followed by modification by coating with nano-alumina sol. (2) The first mixture, the second mixture, clay and potassium feldspar are mixed and then wet-milled to obtain a slurry; by mass percentage, the slurry includes 5-10% modified diatomaceous earth, 4-6% nano Fe2O3, 3-4% nano TiO2, 0.5-1% nano CeO2, 15-25% quartz, 5-10% waste porcelain powder, 40-50% clay and 10-15% potassium feldspar; (3) After the mud is pressed and filtered, it is then vacuum-kneaded and aged to obtain mud segments; (4) After rolling and drying the clay sections, a green body is obtained; (5) After mixing potassium feldspar, quartz, kaolin, calcite, barium carbonate and zinc oxide, water is added and stirred to obtain glaze; by mass percentage, the glaze includes 35-45% potassium feldspar, 20-30% quartz, 5-10% kaolin, 15-20% calcite, 1-5% barium carbonate and 3-8% zinc oxide; the inner side of the green body is glazed by pouring glaze. (6) After the glazed body is fired at high temperature, nano-silica sol is sprayed and sintered to obtain porous ceramic material.

2. The method for preparing porous ceramic materials with oxygen permeability and far-infrared catalytic function as described in claim 1, characterized in that, The density of the diatomaceous earth is 2.0-2.3 g / cm³. 3 The porosity is 80-90%; the coating modification amount of the nano-alumina sol is 10-20% of the diatomaceous earth mass, the solid content of the nano-alumina sol is 20-25%, and the particle size of the nano-alumina is 10-20 nm.

3. The method for preparing porous ceramic materials with oxygen permeability and far-infrared catalytic function as described in any one of claims 1-2, characterized in that, In step (2), the quartz includes coarse-grained quartz and fine-grained quartz with a mass ratio of 2-3:

1. The coarse-grained quartz has a particle size of 150-200μm, and the fine-grained quartz has a particle size of 20-50μm. The waste ceramic powder has a particle size of 40-80μm.

4. The method for preparing porous ceramic materials with oxygen permeability and far-infrared catalytic function as described in claim 1, characterized in that, In step (3), the moisture content of the mud cake obtained after filtration is 19-25%; the aging time is 24-36h.

5. The method for preparing porous ceramic materials with oxygen permeability and far-infrared catalytic function as described in claim 1, characterized in that, In step (5), the solid content of the glaze is 50-55%; the thickness of the glaze is 0.3-0.5 mm.

6. The method for preparing porous ceramic materials with oxygen permeability and far-infrared catalytic function as described in claim 1, 4, or 5, characterized in that, In step (6), the high-temperature firing process is as follows: the temperature is raised to 1200~1280℃, the heating rate is 40-60℃ / h, and the holding time is 5-10h; after high-temperature firing, the temperature is lowered to 700-800℃ at a cooling rate of 20-30℃ / h, and then naturally cooled to room temperature and placed in an oxygen kiln for 24h or more.

7. The method for preparing porous ceramic materials with oxygen permeability and far-infrared catalytic function as described in claim 1, characterized in that, In step (6), the process of spraying nano-silica sol and sintering is as follows: the blank after high-temperature firing and cooling is preheated to 60-80℃, nano-silica sol is sprayed, and then the temperature is raised to 150-200℃ for sintering and held for 20-30 minutes.

8. The method for preparing porous ceramic materials with oxygen permeability and far-infrared catalytic function as described in claim 1 or 7, characterized in that, The solid content of the nano-silica sol is 5-6%, and the particle size of the nano-SiO2 is 10-20nm; after sintering, the thickness of the resulting silica film is 0.5-2μm.

9. The application of a porous ceramic material prepared by the preparation method according to any one of claims 1-8 in brewing.

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