Heterogeneous zinc spinel-based composite active zinc oxide and preparation method thereof and ceramic glaze

Abstract

This invention relates to the field of functional ceramic materials technology, and discloses a multiphase gradient isomeric zinc spinel-based composite active zinc oxide, its preparation method, and ceramic glaze. The preparation method includes the following steps: mixing zinc oxide, aluminum oxide, silicon oxide, magnesium oxide, and rare earth oxide in a certain proportion to obtain a mixture; adding the mixture and an alkoxy compound to a solvent to disperse and form a nano-precursor slurry; subjecting the obtained nano-precursor slurry to reduction-oxidation calcination treatment to obtain a calcined product; and hydrating the obtained calcined product to obtain multiphase gradient isomeric zinc spinel-based composite active zinc oxide. By implementing this invention, the obtained multiphase gradient isomeric zinc spinel-based composite active zinc oxide contains both zinc oxide and spinel phases, exhibits low high-temperature lattice distortion, and possesses superior wear resistance. The introduction of rare earth element R not only enhances the catalytic activity of zinc oxide, increasing its degradation rate of formaldehyde and toluene, but also improves its antibacterial properties.

Description

Technical Field

[0001] This invention relates to the field of functional ceramic materials technology, and in particular to a multiphase gradient heterogeneous zinc spinel-based composite active zinc oxide, its preparation method, and ceramic glaze. Background Technology

[0002] Zinc oxide (ZnO) is a key functional raw material in ceramic glazes, and its performance directly affects the surface quality and functional characteristics of ceramic products. As the ceramic industry continues to demand higher performance from glazes, traditional zinc oxide materials have gradually revealed a series of core technological bottlenecks, making it difficult to meet the application needs of high-end ceramic products.

[0003] Firstly, regarding crystal structure stability, conventional zinc oxide possesses a hexagonal wurtzite structure, but its lattice stability is insufficient, with a lattice constant ratio (c / a = 1.600) lower than the theoretical value (1.633). This leads to the easy triggering of abnormal crystal growth during high-temperature firing at ≥1180℃, resulting in deterioration of the glaze's performance. Consequently, the Mohs hardness of the glaze only reaches 7.2-7.5, the coefficient of friction is >0.3, and according to ISO 7766 standard testing, the wear amount after 5000 hours reaches as high as 0.3 mm. 3 -0.4mm 3 This seriously affects the service life and surface wear resistance of ceramic products.

[0004] Secondly, in terms of functional diversity, traditional zinc oxide lacks photocatalytic active sites, making it unable to achieve the self-cleaning, antibacterial, and formaldehyde degradation functions of the glaze. Actual tests show that its antibacterial rate against Escherichia coli is <50%, and according to GB / T 18204.2-2014 standard, its formaldehyde degradation rate is <10%, which is insufficient to meet the indoor environmental purification requirements of GB 18580-2017 "Formaldehyde Emission Limits in Wood-based Panels and Their Products for Interior Decoration and Renovation," thus limiting the application of ceramic products in high-end homes, medical settings, and other scenarios with strict hygiene and environmental protection requirements.

[0005] Furthermore, in terms of process adaptability, traditional zinc oxide requires a high proportion of 8%-15% to be added to the glaze to meet basic performance requirements, but its surface energy is relatively high (approximately 470 mJ / m²). 2 Uneven dispersion is likely to occur in the glaze slurry, with the residue content on a 325-mesh sieve reaching 0.35%-0.5%, and the glaze slurry suspension stability <12h. This not only increases the cost of raw materials, but also easily causes defects such as pinholes and glaze shrinkage on the glaze surface after firing, reducing the production yield. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a multiphase gradient heterogeneous zinc spinel-based composite active zinc oxide and its preparation method, forming an interlocking structure of continuous zinc oxide phase / spinel reinforcing phase, so that the multiphase gradient heterogeneous zinc spinel-based composite active zinc oxide has super wear resistance, high formaldehyde degradation rate, high toluene degradation rate and excellent antibacterial properties.

[0007] The technical problem to be solved by the present invention is to provide a ceramic glaze with low viscosity, low firing energy consumption, and high yield.

[0008] To address the aforementioned technical problems, the first aspect of this invention provides a method for preparing multiphase gradient isomeric zinc spinel-based composite active zinc oxide, comprising the following steps:

[0009] 63-72 parts by weight of zinc oxide, 18-27 parts by weight of aluminum oxide, 13-22 parts by weight of silicon oxide, 3-10 parts by weight of magnesium oxide and 0.3-1.2 parts by weight of rare earth oxide are mixed in a certain proportion to obtain a mixture. The mixture and an alkoxy compound are added to a solvent, wherein the added mass of the alkoxy compound is 0.5%-1.5% of the added mass of the mixture, and dispersed to form a nano-precursor slurry.

[0010] The obtained nano-precursor slurry was subjected to reduction-oxidation calcination treatment to obtain the calcined product.

[0011] The calcined product was hydrated to obtain multiphase gradient isomeric zinc spinel-based composite active zinc oxide.

[0012] As an improvement to the above scheme, the general chemical formula of the multiphase gradient isomeric zinc spinel-based composite active zinc oxide is: [(ZnO)] x (Si) a Mg b Zn c R d Al2O 4z ] y ,

[0013] Wherein, R is a rare earth element, and R is at least one of Ce and La;

[0014] x=0.2-0.98, a=0.1-0.3, b=0.05-0.15, c=0.05-0.1, d=0.01-0.03, z=0.9-1.1, y=1-5.

[0015] As an improvement to the above scheme, the particle size D of the multiphase gradient isomeric zinc spinel-based composite active zinc oxide is... 50 Its diameter is 5μm-8μm, aspect ratio is 1.5-4, and surface hydroxyl density is 2OH / nm. 2 -3OH / nm2 .

[0016] As an improvement to the above scheme, the obtained nano-precursor slurry is subjected to reduction-oxidation calcination treatment to obtain the calcined product, including the following steps:

[0017] Heat to 800℃-1000℃ and calcine under a reducing atmosphere for 1-2 hours;

[0018] Heat to 1200℃-1250℃ and calcine in an oxidizing atmosphere for 2-3 hours.

[0019] As an improvement to the above scheme, the obtained nano-precursor slurry is subjected to reduction-oxidation calcination treatment to obtain the calcined product, including the following steps:

[0020] Heating to 800℃-1000℃ at a heating rate of 10℃ / min-15℃ / min, and calcining under N2 atmosphere for 1h-2h;

[0021] Heating to 1200℃-1250℃ at a heating rate of 5℃ / min-8℃ / min, and calcining in air for 2-3 hours.

[0022] As an improvement to the above scheme, the alkoxy compound is selected from one or more of γ-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, aminopropylmethyldiethoxysilane, 4-amino-3,3-dimethylbutyltrimethoxysilane, and 2-(2-aminoethoxy-dimethyl-silyl)oxyethylamine.

[0023] The particle size D of the nano-precursor in the nano-precursor slurry 10 The particle size is 100nm-150nm, with a diameter D. 90 The range is 750nm-850nm;

[0024] The nano-precursor slurry contains 30wt%-50wt% nano-precursor content, and the solvent is an aqueous ethanol solution with a volume ratio of ethanol to water of (2.5-3.5):1.

[0025] The particle size D of the zinc oxide 50 The range is 150nm-250nm;

[0026] The particle size D of the alumina 50 The range is 100nm-300nm;

[0027] The silicon oxide is fumed silica, and the particle size D of the fumed silica is... 50 The range is 5nm-30nm;

[0028] The magnesium oxide is active magnesium oxide, and the specific surface area of ​​the active magnesium oxide is 100 m². 2 / g-150m 2 / g.

[0029] As an improvement to the above solution, the hydration treatment includes the following steps:

[0030] The calcined product was ground in water to obtain flaky, multiphase gradient isomeric zinc spinel-based composite active zinc oxide.

[0031] The concentration of the calcined product in water is 0.5wt%-1wt%, and the grinding time is 6h-8h.

[0032] A second aspect of the present invention provides a multiphase gradient isomeric zinc spinel-based composite active zinc oxide for ceramic glazes, which is prepared according to the preparation method described above.

[0033] A third aspect of the present invention provides a ceramic glaze, wherein the raw materials for preparing the ceramic glaze include the aforementioned multiphase gradient isomeric zinc spinel-based composite active zinc oxide;

[0034] The mass of the multiphase gradient isomeric zinc spinel-based composite active zinc oxide used accounts for 3%-8% of the total mass of the ceramic glaze.

[0035] Implementing this invention has the following beneficial effects:

[0036] In this application, a nano-precursor slurry is dispersed and subjected to reduction-oxidation calcination and hydration treatments to obtain a multiphase gradient isomeric zinc spinel-based composite active zinc oxide containing both zinc oxide and spinel phases. The zinc oxide phase forms a flexible electron transport network, while the spinel phase constructs a rigid framework. The two phases are bonded through a low-energy coherent interface, resulting in a small lattice mismatch and low high-temperature lattice distortion rate. This forms an interlocking structure of continuous zinc oxide phase / spinel-reinforced phase, which improves the ultra-wear resistance of the multiphase gradient isomeric zinc spinel-based composite active zinc oxide. Furthermore, the introduction of rare earth element R for doping regulates the oxygen vacancy concentration, thereby enhancing the catalytic activity of the multiphase gradient isomeric zinc spinel-based composite active zinc oxide, increasing its degradation rate of formaldehyde and toluene, and improving its antibacterial properties. Attached Figure Description

[0037] Figure 1 XRD pattern of multiphase gradient isomeric zinc spinel-based composite active zinc oxide obtained in Example 1;

[0038] Figure 2 SEM image of the multiphase gradient isomeric zinc spinel-based composite active zinc oxide obtained in Example 1. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments will be described in further detail below.

[0040] To address the above problems, the first aspect of this invention provides a method for preparing multiphase gradient isomeric zinc spinel-based composite active zinc oxide, comprising the following steps:

[0041] (1) Mix 63-72 parts by mass of zinc oxide, 18-27 parts by mass of aluminum oxide, 13-22 parts by mass of silicon oxide, 3-10 parts by mass of magnesium oxide and 0.3-1.2 parts by mass of rare earth oxide in a certain proportion to obtain a mixture. Add the mixture and alkoxy compound to a solvent and disperse to form a nano precursor slurry.

[0042] (2) The obtained nano precursor slurry was subjected to reduction-oxidation calcination treatment to obtain the calcined product;

[0043] (3) The calcined product was hydrated to obtain multiphase gradient isomeric zinc spinel-based composite active zinc oxide.

[0044] In this invention, the chemical formula of the multiphase gradient isomeric zinc spinel-based composite active zinc oxide obtained by the above preparation method is: [(ZnO)] x (Si) a Mg b Zn c R d Al2O 4z ] y In this compound, R is a rare earth element, and R is at least one of Ce and La. The multiphase gradient isomeric zinc spinel-based composite active zinc oxide contains a zinc oxide phase and a spinel phase. The zinc oxide phase forms a flexible electron transport network, while the spinel phase constructs a rigid framework. The two are bonded through a low-energy coherent interface, resulting in a small lattice mismatch and low high-temperature lattice distortion rate. This forms an interlocking structure of a continuous zinc oxide phase and a spinel-reinforced phase, improving the ultra-wear resistance of the multiphase gradient isomeric zinc spinel-based composite active zinc oxide. Furthermore, the introduction of rare earth element R for doping regulates the oxygen vacancy concentration, enhancing the catalytic activity of the multiphase gradient isomeric zinc spinel-based composite active zinc oxide, increasing its degradation rate of formaldehyde and toluene, and improving its antibacterial properties.

[0045] Specifically, the multiphase gradient isomeric zinc spinel-based composite active zinc oxide uses ZnO as a matrix to form a continuous phase framework and regulate Zn content. 2+ The interstitial concentration of Al2O4, as the spinel matrix framework, is used to produce active zinc oxide. Si doping replaces some of the Al in the spinel, producing Si 4+ It can then replace Al with different valences. 3+Oxygen vacancies are generated, forming photocatalytic active sites. Mg doping replaces the divalent metal sites in spinel, producing Mg 2+ It can fill the tetrahedral voids of spinel, stabilize the Fd-3m cubic structure of the multiphase gradient isomeric zinc spinel-based composite active zinc oxide, improve ion conductivity. After self-doping, Zn exists simultaneously in the trivalent metal sites of zinc oxide and spinel, which can form donor levels, strengthen the interfacial bonding between the two phases, promote the dispersion of active components, and improve electron mobility. The addition of rare earth element R can effectively regulate the oxygen vacancy concentration and prolong the lifetime of photogenerated carriers.

[0046] Wherein, when R is Ce, the generated Ce 3+ In a spinel structure, it can act as an electron trap to capture holes, suppress photogenerated carrier recombination, and prolong carrier lifetime; simultaneously, it can be reversibly oxidized to Ce. 4+ Releasing electrons promotes the generation of reactive oxygen species, improving catalytic efficiency and increasing formaldehyde degradation rate. When R is La, it can act as an electron trap to capture holes, improving quantum efficiency and extending carrier lifetime. Furthermore, doping can expand spinel cell parameters, reduce grain boundary mobility, increase material stability, inhibit grain growth, ensure material hardness, form a high-density hydroxyl interface, and promote Zn degradation. 2+ Slow-release, improving the antibacterial properties of the material.

[0047] Furthermore, x represents the molar proportion of the zinc oxide phase, x = 0.2-0.98. By controlling the content of zinc oxide in the multiphase gradient isomeric zinc spinel-based composite active zinc oxide, the Zn content can be adjusted. 2+ The interstitial concentration is at 10 18 cm -3 -10 19 cm -3 This allows for the regulation of the optical bandgap width, thereby further optimizing the conductivity and mechanical strength of the complex gradient heterogeneous zinc spinel-based composite active zinc oxide.

[0048] Furthermore, a represents the mole fraction of Si dopant in the spinel phase, with a = 0.1-0.3. By controlling the Si doping concentration in the multiphase gradient isomeric zinc spinel-based composite active zinc oxide, the concentration of oxygen vacancies generated can be further regulated, and the activation energy (Ea) can be reduced to below 0.65 eV.

[0049] Furthermore, b is the mole fraction of Mg, the doping element in the spinel phase, with b = 0.05-0.15. By controlling the doping concentration of Mg in the multiphase gradient isomeric zinc spinel-based composite active zinc oxide, the lattice distortion rate can be made less than 0.1% with the synergistic effect of other components.

[0050] Furthermore, c represents the mole fraction of Zn in the spinel phase, with c = 0.05-0.1. By controlling the Zn self-doping concentration in the multiphase gradient isomeric zinc spinel-based composite active zinc oxide, and with the synergistic effect of other components, the ionization energy (Eg) of the multiphase gradient isomeric zinc spinel-based composite active zinc oxide can be increased. t The concentration of electrons in the conduction band is reduced to as low as 0.03 eV, significantly increasing the concentration. Furthermore, Zn self-doping can form a near-degenerate doped state, reducing the effective mass of electrons at the bottom of the conduction band and filling oxygen vacancies, thus reducing lattice distortion and ionized impurity scattering, thereby increasing electron mobility to 200 cm⁻¹. 2 / V·s.

[0051] Furthermore, d represents the mole fraction of dopant element R in the spinel phase, d = 0.01-0.03, where R is a rare earth element that substitutes for Zn at the A site in the spinel. 2+ By inducing lattice charge imbalance through heterovalent doping, oxygen vacancies are generated and preferentially captured by photogenerated holes, reducing their recombination probability with conduction band electrons. With the synergistic effect of Si doping, the oxygen vacancy concentration in the complex gradient heterogeneous zinc spinel-based composite active zinc oxide is regulated, and the photogenerated carrier lifetime (τ) of the complex gradient heterogeneous zinc spinel-based composite active zinc oxide reaches 2.8 μs.

[0052] Furthermore, y represents the number of structural periods, y = 1-5. By controlling the number of layers and periodicity of the composite structure, the microstructure and performance of the material can be optimized.

[0053] Understandably, z is the spinel phase lattice distortion factor, z=0.9-1.1, which can control the degree of lattice distortion and optimize the oxygen vacancy concentration.

[0054] Furthermore, the [(ZnO)] x (Si) a Mg b Zn c R d (Al2O4) z ] y The oxygen vacancy concentration was 1.0 × 10⁻⁶. 17 cm -3 -5.0×10 18 cm -3 The spinel phase content is greater than or equal to 95%. Oxygen vacancies can capture O2 to form superoxide radicals, promoting the surface hydroxyl density and Zn. 2+ The release of the spinel phase generates more photocatalytic active sites, which, together with the increased spinel phase content, enhances the degradation rate of formaldehyde and antibacterial properties. Moreover, the spinel phase provides a rigid framework, and the oxygen vacancies at this concentration will not cause lattice distortion, thus ensuring the hardness and wear resistance of the multiphase gradient heterogeneous zinc spinel-based composite active zinc oxide.

[0055] In some specific and preferred embodiments, the particle size D of the multiphase gradient isomeric zinc spinel-based composite active zinc oxide is... 50 Its diameter is 5μm-8μm, aspect ratio is 1.5-4, and surface hydroxyl density is 2OH / nm. 2 -3OH / nm 2 The resulting multiphase gradient heterogeneous zinc spinel-based composite active zinc oxide has good hydrophilicity as a glaze component. During sintering, it will produce a directional arrangement effect, forming micropores between the layers to relieve thermal stress and improve the crack resistance of the glaze.

[0056] Each step will be explained in detail below.

[0057] In step (1), the alkoxy compound can be hydrolyzed in the solvent to generate active silanol, which then reacts with the active groups present in the mixture to form stable covalent bonds, forming a bonding layer on the surface of the oxide particles, realizing the bonding between multiple oxides. At the same time, the dispersion stability of the oxides in the solvent is improved after treatment with the alkoxy compound.

[0058] Preferably, the alkoxy compound is a siloxane compound containing an amino group, which reduces the viscosity of the nano-precursor slurry. The amino group can form coordination bonds with oxygen vacancies in rare earth oxides, enhancing interfacial bonding strength, and react with active groups on the surface of adjacent oxides, suppressing phase separation caused by density differences. The alkoxy compound is added at 0.5%-1.5% of the total mass of the mixture, significantly modifying the oxides and fully utilizing steric hindrance and electrostatic repulsion to ensure the dispersion stability of the mixture, reducing the viscosity of the nano-precursor slurry by approximately 40%.

[0059] Optionally, the alkoxy compound is selected from one or more of γ-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, aminopropylmethyldiethoxysilane, 4-amino-3,3-dimethylbutyltrimethoxysilane, and 2-(2-aminoethoxy-dimethyl-silyl)oxyethylamine.

[0060] Furthermore, the nano-precursor slurry contains 30wt%-50wt% of the nano-precursor, and the solvent is an aqueous ethanol solution with a volume ratio of ethanol to water of (2.5-3.5):1, which provides a suitable polar environment for the reaction and balances the hydrolysis reaction of the alkoxy compounds and the dispersion stability of the nano-precursor slurry. For example, the nano-precursor slurry contains 30wt%, 35wt%, 40wt%, 45wt%, or 50wt% of the nano-precursor, but is not limited to this.

[0061] Furthermore, the particle size D of the nano-precursor in the nano-precursor slurry 10The particle size is 100nm-150nm, with a diameter D. 90 The particle size is 750nm-850nm. At this size, the nano-precursors in the nano-precursor slurry have good dispersibility, and the sedimentation rates of different components in the system are similar. They are not prone to agglomeration or phase separation, and have high thermal conductivity, which is beneficial for calcination and allows them to maintain their original morphology after calcination. If the particle size of the nano-precursors is too small, the particles have high surface energy and large specific surface area, making them prone to agglomeration. During calcination, problems such as local overheating and low crystallinity of zinc spinel are likely to occur, forming a dense sintered body, which leads to reduced catalytic activity. At the same time, the oxygen vacancy anode in the system will cause disordered growth at the interface. If the particle size of the nano-precursors is too large, the thermal resistance increases, the decomposition of the core region is delayed, leading to the generation of impurity phases. Moreover, the water molecule penetration is hindered during the later hydration process, resulting in uneven hydration layer thickness. For example, the particle size D of the nano-precursors in the nano-precursor slurry is... 10 The particle size D is 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, but not limited to these. 90 The nm wavelengths are 750nm, 770nm, 790nm, 810nm, 830nm, and 850nm, but are not limited to these.

[0062] In some embodiments, an ultrasonic dispersion process can be used to disperse the mixture in a solvent to form a nano-precursor slurry. In the ultrasonic dispersion process, the ultrasonic power is 400W-600W and the ultrasonic frequency is 20kHz-60kHz.

[0063] Optionally, the particle size D of the zinc oxide 50 The alumina has a particle size of 150nm-250nm and a purity of ≥99.5%. 50 The alumina has a particle size of 100nm-300nm and a purity of ≥99.5%. The silicon oxide is fumed silica with a high density of hydroxyl groups on its surface, exhibiting good reactivity with alkoxy compounds. The particle size D of the fumed silica is... 50 The nanometer diameter is 5nm-30nm. The magnesium oxide is active magnesium oxide, whose surface is rich in defect sites, which can significantly improve the bonding efficiency with alkoxy compounds and enhance the interfacial bonding strength of multi-component compounds. The specific surface area of ​​the active magnesium oxide is 100m². 2 / g-150m 2 / g. The synergistic effect of the particle sizes of various oxides can form a uniformly dispersed and stable slurry, promoting the formation of zinc oxide phase and zinc spinel phase during the later calcination process.

[0064] In step (2), calcination in a reducing atmosphere effectively inhibits metal oxidation and promotes the formation of the continuous zinc oxide phase. Subsequently, calcination is carried out in an oxidizing atmosphere, where zinc oxide reacts with aluminum oxide and magnesium oxide to form zinc spinel. Rare earth oxides act as mineralizing agents, lowering the nucleation energy barrier of the spinel phase and increasing crystallinity. In addition, the two-step calcination process exposes more surface area in the hydration treatment of the resulting fine grains, which can increase the hydroxyl density and enhance the hydrophilicity of the material.

[0065] Specifically, in step (2), the obtained nano-precursor slurry is subjected to reduction-oxidation calcination treatment to obtain the calcined product, including:

[0066] (21) Heat to 800℃-1000℃ and calcine in a reducing atmosphere for 1-2 hours;

[0067] In this step, reduction sintering at a lower temperature of 800℃-1000℃ can suppress premature oxidation, promote the decomposition of nano precursors into nanocrystal nuclei, and limit the activity of oxygen molecules in the reducing atmosphere. Calcination in the temperature range of 800℃-1000℃ can initially control the oxygen vacancy concentration within the preset concentration, avoid lattice distortion, and lay a low-defect substrate for the subsequent oxidation stage.

[0068] Optionally, the reducing atmosphere refers to an atmosphere in which the oxygen content is less than 0.5%. Specifically, a reducing atmosphere can be formed by introducing N2, wherein the introduced N2 is high-purity N2 with a purity of 99.99%, and the N2 flow rate is controlled at 450 mL / min-500 mL / min to ensure that the oxygen content in the reaction atmosphere is less than 0.5%.

[0069] Preferably, the temperature is increased to 800℃-1000℃ at a heating rate of 10℃ / min-15℃ / min, and calcined under N2 atmosphere for 1h-2h. This allows the zinc oxide precursor to fully remove hydroxyl groups and organic residues under a reducing atmosphere, avoiding bubble defects and forming uniform nanocrystal nuclei. The optimized grain size is 200nm-300nm. Furthermore, the loss of zinc components can be reduced during the heating process, ensuring the content of zinc spinel phase.

[0070] Furthermore, the calcination temperature is 930℃-970℃.

[0071] (22) Heat to 1200℃-1250℃ and calcine in an oxidizing atmosphere for 2h-3h.

[0072] In this step, high-temperature oxidation calcination promotes the uniformity of zinc spinel grain size, enhances the crystallinity of the zinc spinel phase, forms an Al-O-Zn coherent interface, and improves the thermal stability of the multiphase gradient heterogeneous zinc spinel-based composite active zinc oxide material. The oxidizing atmosphere activates rare earth dopants, precisely controlling the oxygen vacancy concentration to 1.0 × 10⁻⁶. 17 cm -3 -5.0×10 18 cm -3 This enhances photocatalytic efficiency and improves electron mobility. Furthermore, the high temperature of 1200℃-1250℃ can reduce the low lattice mismatch between the zinc oxide phase and the zinc spinel phase, achieving an interlocked structure of "zinc oxide continuous phase / zinc spinel reinforced phase", which significantly improves the hardness and wear resistance of the material.

[0073] Optionally, the oxidizing atmosphere refers to an atmosphere with an oxygen content greater than 21%. Specifically, an oxidizing atmosphere can be formed by introducing air.

[0074] Preferably, the temperature is increased to 1200℃-1250℃ at a heating rate of 5℃ / min-8℃ / min, and calcined in air for 2-3 hours, resulting in a spinel phase yield greater than 95%. After reduction calcination, the heating rate is controlled at 5℃ / min-8℃ / min to promote the full diffusion of rare earth element R to the lattice sites, forming a stable Al-O-Zn gradient interface, thus increasing the spinel phase yield to greater than 95% and providing more active sites for photocatalysis. The two calcination treatments work synergistically to achieve comprehensive optimization of grain size, interfacial bonding energy, and defect concentration. If the heating rate is too slow, it will lead to excessive growth of the spinel phase, reducing the specific surface area and causing a decrease in hydration activity.

[0075] In step (3), by hydrating the calcined product, a nano-scale hydroxylation layer can be formed on the surface of the calcined product, thereby significantly improving the antibacterial properties, catalytic activity, wear resistance, and glaze compatibility of the material. The hydration process causes the Zn-O bonds on the surface of the calcined product to react with water molecules, forming high-density hydroxyl groups. This hydroxyl layer, as the active center of the zinc oxide photocatalytic reaction, can generate reactive oxygen free radicals (·OH), which can destroy bacterial cell membranes through electrostatic adsorption and continuously release Zn²⁺. + Ions achieve antibacterial properties, resulting in a high sterilization rate. Furthermore, hydroxylation treatment can regulate the energy band and reduce the viscosity of the glaze.

[0076] Preferably, the hydration treatment includes: grinding the obtained calcined product in water to obtain sheet-like multiphase gradient isomeric zinc spinel-based composite active zinc oxide. The aqueous environment can suppress mechanical stress from damaging the crystal structure and maintain the integrity of the coherent interface between the spinel phase and the zinc oxide phase. Specifically, the obtained multiphase gradient isomeric zinc spinel-based composite active zinc oxide is in the form of sesame seed cake-shaped sheet particles.

[0077] Furthermore, the concentration of the calcined product in water is 0.5wt%-1wt%. At this time, the hydroxyl content is controlled at 1mmol / g-2mmol / g, which can reduce the mechanical shear force during grinding, avoid flaky breakage, and prevent high-concentration particles from colliding with each other during grinding, causing the active sites to be shielded, resulting in uneven distribution of hydroxyl density, and widening the sintering temperature window of the glaze.

[0078] In some specific and preferred embodiments, the grinding time is 6h-8h, and the obtained calcined product can be ground by ball milling. Specifically, ball milling can be carried out in a polyurethane ball mill jar, the grinding balls are zirconium oxide, the ball-to-material ratio is (9-11):1, the diameter of the grinding balls is 2mm-4mm, and the grinding speed is 200rpm-500rpm.

[0079] A second aspect of the present invention also provides a multiphase gradient isomeric zinc spinel-based composite active zinc oxide for ceramic glazes, which is prepared according to the above-described preparation method.

[0080] In this invention, the multiphase gradient isomeric zinc spinel-based composite active zinc oxide obtained by this preparation method exhibits superior wear resistance, with a Mohs hardness reaching 8.5 and a coefficient of friction of approximately 0.12±0.01. The wear loss after 5000 hours is approximately 0.12±0.02 mm. 3 Compared with traditional zinc oxide materials, it reduces the amount of bacteria by about 65.7%, and the antibacterial rate against Escherichia coli and Staphylococcus aureus reaches more than 99%. Under 365nm ultraviolet light irradiation, the formaldehyde degradation rate reaches 98.5% and the toluene degradation rate reaches 92%.

[0081] A third aspect of the present invention provides a ceramic glaze, wherein the raw materials for preparing the ceramic glaze include the aforementioned multiphase gradient isomeric zinc spinel-based composite active zinc oxide.

[0082] Preferably, the mass of the multiphase gradient isomeric zinc spinel-based composite active zinc oxide accounts for 3%-8% of the total mass of the ceramic glaze.

[0083] In some embodiments, when sintering the ceramic glaze, the sintering temperature can be controlled at 1200℃-1220℃, and the oxygen partial pressure in the sintering atmosphere can be controlled at 1×10⁻⁶. -8 atm-1×10 -6 The sintering time is 25-40 minutes.

[0084] In this application, the glaze containing multiphase gradient isomeric zinc spinel-based composite active zinc oxide has low viscosity and good fluidity, with a viscosity of less than 1500 mPa·s at 300 rpm and a glaze slurry specific gravity of 1.75-1.80 g / cm³. 3It can be uniformly and stably dispersed in the system, ensuring suspension stability ≥48h. Furthermore, the thermal conductivity of the spinel phase in the multiphase gradient heterogeneous zinc spinel-based composite active zinc oxide is increased to 35W / m·K, compared to 25W / m·K of traditional zinc oxide, thus improving the thermal conductivity of the glaze. Hydration treatment widens the sintering temperature window, thereby increasing the sintering temperature while reducing energy consumption and lowering costs.

[0085] Furthermore, due to the excellent wear resistance and antibacterial properties of multiphase gradient isomeric zinc spinel-based composite active zinc oxide, the yield of fired ceramic glazes has increased from 3.0% to 0.9%, and the rate of superior products has also increased significantly from 68% to 90%, further reducing its cost in industrial ceramic glazes, and the product quality has also reached export standards.

[0086] The present invention will be further described below with reference to specific embodiments:

[0087] Example 1

[0088] This embodiment provides a multiphase gradient isomeric zinc spinel-based composite active zinc oxide with the general chemical formula [(ZnO)]. 0.80 (Si) 0.20 Mg 0.10 Zn 0.08 Ce 0.02 Al2O4]3;

[0089] The preparation method is as follows:

[0090] (1) By mass, 70 parts of zinc oxide, 20 parts of aluminum oxide, 15 parts of fumed silica, 5 parts of magnesium oxide, and 1.0 parts of cerium oxide are mixed in a certain proportion to obtain a mixture. The mixture is reacted with 1.0 wt% γ-aminopropyltriethoxysilane and ultrasonically dispersed in an ethanol aqueous solution to form a nano-precursor slurry. The content of nano-precursors in the nano-precursor slurry is 40 wt%, and the particle size D of the nano-precursors is... 10 The particle size is 120 nm, and the particle size D is... 90 It is 800nm;

[0091] Among them, the particle size D of zinc oxide 50 The particle size of alumina is 200 nm; 50 The particle size D of fumed silica is 200 nm. 50 The specific surface area is 15 nm; the magnesium oxide is active magnesium oxide, and the specific surface area of ​​active magnesium oxide is 120 m². 2 / g; the purity of cerium oxide is greater than or equal to 99.9%; the volume ratio of ethanol to water in the ethanol-water solution is 3:1; the ultrasonic power of ultrasonic dispersion is 500W and the frequency is 40kHz.

[0092] (2) The temperature was increased to 950℃ at a heating rate of 12℃ / min and calcined in N2 atmosphere for 1.5h; then the temperature was increased to 1220℃ at a heating rate of 6℃ / min and calcined in air atmosphere for 2.5h to obtain the calcined product.

[0093] (3) Add deionized water to the obtained calcined product and grind it in a polyurethane ball mill at a speed of 300 rpm for 8 hours to obtain a plate-like multiphase gradient isomeric zinc spinel-based composite active zinc oxide. The concentration of the calcined product in water is 0.8 wt%, the grinding ball is zirconium oxide, the ball-to-material ratio is 10:1, and the diameter of the grinding ball is 3 mm.

[0094] Example 2

[0095] This embodiment provides a multiphase gradient isomeric zinc spinel-based composite active zinc oxide with the general chemical formula [(ZnO)]. 0.70 (Si) 0.25 Mg 0.12 Zn 0.07 La 0.015 Al2O4]3;

[0096] The preparation method is as follows:

[0097] (1) By mass, 65 parts of zinc oxide, 25 parts of aluminum oxide, 20 parts of fumed silica, 8 parts of magnesium oxide, and 0.5 parts of lanthanum oxide are mixed in a certain proportion to obtain a mixture. The mixture is reacted with 1.5 wt% γ-aminopropyltriethoxysilane and ultrasonically dispersed in an ethanol aqueous solution to form a nano-precursor slurry. The content of nano-precursors in the nano-precursor slurry is 40 wt%, and the particle size D of the nano-precursors is... 10 The particle size is 120 nm, and the particle size D is... 90 It is 800nm;

[0098] Among them, the particle size D of zinc oxide 50 The particle size of alumina is 200 nm; 50 The particle size D of fumed silica is 200 nm. 50 The specific surface area is 15 nm; the magnesium oxide is active magnesium oxide, and the specific surface area of ​​active magnesium oxide is 120 m². 2 / g; the purity of lanthanum oxide is greater than or equal to 99.9%; the volume ratio of ethanol to water in the ethanol-water solution is 3:1, the ultrasonic power of ultrasonic dispersion is 500W, and the frequency is 40kHz.

[0099] (2) The temperature was increased to 950℃ at a heating rate of 12℃ / min and calcined in N2 atmosphere for 1.5h; then the temperature was increased to 1220℃ at a heating rate of 6℃ / min and calcined in air atmosphere for 2.5h to obtain the calcined product.

[0100] (3) Add deionized water to the obtained calcined product and grind it in a polyurethane ball mill at a speed of 300 rpm for 8 hours to obtain a plate-like multiphase gradient isomeric zinc spinel-based composite active zinc oxide. The concentration of the calcined product in water is 0.8 wt%, the grinding ball is zirconium oxide, the ball-to-material ratio is 10:1, and the diameter of the grinding ball is 3 mm.

[0101] Example 3

[0102] This embodiment provides a multiphase gradient isomeric zinc spinel-based composite active zinc oxide with the general chemical formula [(ZnO)]. 0.80 (Si) 0.20 Mg 0.10 Zn 0.08 Ce 0.02 Al2O4]3;

[0103] Its preparation method is basically the same as that in Example 1, except that,

[0104] (2) The temperature was increased to 950℃ at a heating rate of 12℃ / min and calcined in N2 atmosphere for 1.5h; then the temperature was increased to 1230℃ at a heating rate of 6℃ / min and calcined in air atmosphere for 2h to obtain the calcined product.

[0105] (3) Add deionized water to the obtained calcined product and grind it in a polyurethane ball mill at a speed of 300 rpm for 6 hours to obtain a plate-like multiphase gradient isomeric zinc spinel-based composite active zinc oxide. The concentration of the calcined product in water is 0.8 wt%, the grinding ball is zirconium oxide, the ball-to-material ratio is 10:1, and the diameter of the grinding ball is 3 mm.

[0106] Example 4

[0107] This embodiment provides a multiphase gradient isomeric zinc spinel-based composite active zinc oxide with the general chemical formula [(ZnO)]. 0.80 (Si) 0.20 Mg 0.10 Zn 0.08 Ce 0.02 Al2O4]3;

[0108] Its preparation method is basically the same as that in Example 3, except that,

[0109] (2) The temperature was increased to 950℃ at a heating rate of 5℃ / min and calcined in N2 atmosphere for 1.5h; then the temperature was increased to 1220℃ at a heating rate of 10℃ / min and calcined in air atmosphere for 2.5h to obtain the calcined product.

[0110] Example 5

[0111] This embodiment provides a multiphase gradient isomeric zinc spinel-based composite active zinc oxide with the general chemical formula [(ZnO)]. 0.80 (Si) 0.20 Mg 0.10 Zn 0.08 Ce 0.02 Al2O4]3;

[0112] Its preparation method is basically the same as that in Example 3, except that,

[0113] The preparation method of the multiphase gradient isomeric zinc spinel-based composite active zinc oxide is as follows:

[0114] (3) The obtained calcined product is dried and ground to obtain multiphase gradient isomeric zinc spinel-based composite active zinc oxide, wherein the ball-to-material ratio is 10:1 and the diameter of the grinding ball is 3 mm.

[0115] Comparative Example 1

[0116] This comparative example provides a conventional zinc oxide with a particle size D. 50 The size is 1μm, and the purity is 99.0%.

[0117] (a) The zinc oxide obtained in Examples 1-5 and Comparative Example 1 was tested, as follows:

[0118] 1. Microscopic properties: XRD and SEM scans were performed on the multiphase gradient isomeric zinc spinel-based composite active zinc oxide obtained in Example 1. The test results are shown in [Figure 1]. Figure 1 , Figure 2 .

[0119] 2. Mohs hardness: The multiphase gradient isomeric zinc spinel-based composite active zinc oxide prepared in the examples and the zinc oxide in the comparative examples were tested according to ISO 2679 standard. The test results are shown in Table 1.

[0120] 3. Friction coefficient: The multiphase gradient isomeric zinc spinel-based composite active zinc oxide prepared in the example and the zinc oxide in the comparative example were tested according to ASTM D1894 standard. The test results are shown in Table 1.

[0121] 4. Formaldehyde degradation rate: The multiphase gradient isomeric zinc spinel-based composite active zinc oxide prepared in the example and the zinc oxide in the comparative example were tested according to GB / T 18204.2-2014 standard. The test results are shown in Table 1.

[0122] 5. Toluene degradation rate: The multiphase gradient isomeric zinc spinel-based composite active zinc oxide prepared in the examples and the zinc oxide in the comparative examples were tested according to GB / T 18204.2-2014 standard. The test results are shown in Table 1.

[0123] 6. Antibacterial rate: The antibacterial properties of the multiphase gradient isomeric zinc spinel-based composite active zinc oxide prepared in the examples and the zinc oxide in the comparative examples against Escherichia coli and Staphylococcus aureus were tested according to ATCC 25922 and ATCC 6538 standards. The test results are shown in Table 1.

[0124] Table 1 Performance test results of the examples and comparative examples

[0125]

[0126] As shown in Table 1 above, the multiphase gradient isomeric zinc spinel-based composite active zinc oxide obtained by the preparation method of the present invention contains a zinc oxide phase and a spinel phase, forming an interlocking structure of continuous zinc oxide phase / spinel-reinforced phase, which improves the ultra-wear resistance of multiphase gradient isomeric zinc spinel-based composite active zinc oxide. Moreover, the introduction of rare earth element R for doping regulates the oxygen vacancy concentration, which not only enhances the catalytic activity of multiphase gradient isomeric zinc spinel-based composite active zinc oxide and strengthens its degradation rate of formaldehyde and toluene, but also improves its antibacterial properties.

[0127] Combination Figure 1 and Figure 2 , Figure 1 The presence of spinel phase characteristic peaks indicates the presence of a spinel phase in the multiphase gradient isomeric zinc spinel-based composite active zinc oxide obtained by the preparation method of this invention. Figure 2 The results show that the multiphase gradient isomeric zinc spinel-based composite active zinc oxide has a flaky, sesame-cake-like particle morphology, proving the successful preparation of the multiphase gradient isomeric zinc spinel-based composite active zinc oxide. Meanwhile, from... Figure 2 It can be seen that the particle size D of the multiphase gradient isomeric zinc spinel-based composite active zinc oxide is... 50 Its diameter is 5μm-8μm, aspect ratio is 1.5-4, and surface hydroxyl density is 2OH / nm. 2 -3OH / nm 2 .

[0128] (ii) The zinc oxide obtained in Examples 1-5 and Comparative Example 1 was added to ceramic glaze, and then the ceramic glaze was fired. The concentration of zinc oxide added was 5 wt%, the sintering temperature was controlled at 1200℃, and the oxygen partial pressure in the sintering atmosphere was 1 × 10⁻⁶. -8 The sintering time is 25 minutes (atm). Details are as follows:

[0129] 1. Specific gravity: The specific gravity of the ceramic glazes obtained in the examples and comparative examples was tested, and the test results are shown in Table 2.

[0130] 2. Particle uniformity: The ceramic glazes obtained in the examples and comparative examples were passed through a 325-mesh sieve to determine their particle uniformity. The test results are shown in Table 2.

[0131] 3. Suspension stability: The suspension stability of the ceramic glazes obtained in the examples and comparative examples was tested according to GB / T 17434-2008 standard. The test results are shown in Table 2.

[0132] 4. Energy consumption of glaze firing: The energy consumption of the ceramic glazes obtained in the examples and comparative examples was tested. The energy consumption of the glazes obtained in the examples was calculated based on the energy consumption of the comparative example 1. The test results are shown in Table 2.

[0133] Table 2 Performance test results of ceramic glazes obtained in the examples and comparative examples

[0134]

[0135] As can be seen from the above results, the multiphase gradient isomeric zinc spinel-based composite active zinc oxide of the present invention, when used in glazes, results in glazes with low viscosity and good fluidity, which can be uniformly and stably dispersed in the system, with good suspension stability. Moreover, it increases the sintering temperature but reduces the sintering energy consumption during firing.

[0136] The above description is merely a preferred embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A method for preparing a multiphase gradient isomeric zinc spinel-based composite active zinc oxide, characterized in that, Includes the following steps: 63-72 parts by weight of zinc oxide, 18-27 parts by weight of aluminum oxide, 13-22 parts by weight of silicon oxide, 3-10 parts by weight of magnesium oxide and 0.3-1.2 parts by weight of rare earth oxide are mixed in a certain proportion to obtain a mixture. The mixture and an alkoxy compound are added to a solvent, wherein the added mass of the alkoxy compound is 0.5%-1.5% of the added mass of the mixture, and dispersed to form a nano-precursor slurry. The obtained nano-precursor slurry was subjected to reduction-oxidation calcination treatment to obtain the calcined product. The calcined product was subjected to hydration treatment to obtain multiphase gradient isomeric zinc spinel-based composite active zinc oxide; The general chemical formula for multiphase gradient isomeric zinc spinel-based composite active zinc oxide is: [(ZnO)] x (Si) a Mg b Zn c R d Al2O 4z ] y , Wherein, R is a rare earth element, and R is at least one of Ce and La; x=0.2-0.98, a=0.1-0.3, b=0.05-0.15, c=0.05-0.1, d=0.01-0.03, z=0.9-1.1, y=1-5; The alkoxy compound is a siloxane compound containing an amino group; The obtained nano-precursor slurry was subjected to reduction-oxidation calcination treatment to obtain the calcined product, including the following steps: Heat to 800℃-1000℃ and calcine under a reducing atmosphere for 1-2 hours; Heat to 1200℃-1250℃ and calcine under an oxidizing atmosphere for 2-3 hours; The particle size D of the zinc oxide 50 The range is 150nm-250nm; The particle size D of the alumina 50 The range is 100nm-300nm; The silicon oxide is fumed silica, and the particle size D of the fumed silica is... 50 The range is 5nm-30nm; The magnesium oxide is active magnesium oxide, and the specific surface area of ​​the active magnesium oxide is 100 m². 2 / g-150m 2 / g.

2. The method for preparing multiphase gradient isomeric zinc spinel-based composite active zinc oxide as described in claim 1, characterized in that, The particle size D of the multiphase gradient isomeric zinc spinel-based composite active zinc oxide 50 Its diameter is 5μm-8μm, aspect ratio is 1.5-4, and surface hydroxyl density is 2OH / nm. 2 -3OH / nm 2 .

3. The method for preparing multiphase gradient isomeric zinc spinel-based composite active zinc oxide as described in claim 1, characterized in that, The obtained nano-precursor slurry was subjected to reduction-oxidation calcination treatment to obtain the calcined product, including the following steps: Heating to 800℃-1000℃ at a heating rate of 10℃ / min-15℃ / min, and calcining under N2 atmosphere for 1h-2h; Heating to 1200℃-1250℃ at a heating rate of 5℃ / min-8℃ / min, and calcining in air for 2-3 hours.

4. The method for preparing multiphase gradient isomeric zinc spinel-based composite active zinc oxide as described in claim 1, characterized in that, The alkoxy compound is selected from one or more of γ-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, aminopropylmethyldiethoxysilane, 4-amino-3,3-dimethylbutyltrimethoxysilane, and 2-(2-aminoethoxy-dimethyl-silyl)oxyethylamine. The particle size D of the nano-precursor in the nano-precursor slurry 10 The particle size is 100nm-150nm, with a diameter D. 90 The range is 750nm-850nm; The nano-precursor slurry contains 30wt%-50wt% nano-precursor content, and the solvent is an aqueous ethanol solution with a volume ratio of ethanol to water of (2.5-3.5):

1.

5. The method for preparing multiphase gradient isomeric zinc spinel-based composite active zinc oxide as described in claim 1, characterized in that, The hydration treatment includes the following steps: The calcined product was ground in water to obtain flaky, multiphase gradient isomeric zinc spinel-based composite active zinc oxide. The concentration of the calcined product in water is 0.5wt%-1wt%, and the grinding time is 6h-8h.

6. A multiphase gradient isomeric zinc spinel-based composite active zinc oxide for use in ceramic glazes, characterized in that, It is prepared according to any one of claims 1-5.

7. A ceramic glaze, characterized in that, The raw materials for preparing the ceramic glaze include the multiphase gradient isomeric zinc spinel-based composite active zinc oxide as described in claim 6.

8. The ceramic glaze as described in claim 7, characterized in that, The mass of the multiphase gradient isomeric zinc spinel-based composite active zinc oxide used accounts for 3%-8% of the total mass of the ceramic glaze.

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