White dry granules with multi-layer three-dimensional effect and preparation method of white dry granules

Abstract

The invention discloses white dry granules with a multi-layer three-dimensional effect and a preparation method thereof, and relates to the technical field of building ceramic materials. The white dry granules with the multi-layer three-dimensional effect are prepared from a frit base material and a rare earth calcium phosphate additive, rare earth and calcium phosphate are added into a frit base material to serve as an additive, the high refractive index of oxides of La < 3 + > and Ce < 3 + > is utilized, refractive index difference is formed between the oxides of La < 3 + > and Ce < 3 + > and the frit base material, and light rays are subjected to multiple scattering and refraction at an interface; and meanwhile, the refractive index gradient is formed through particle size grading synergism, the reflection and refraction paths of light rays among particles with different particle sizes are different, and the visual'depth sense 'is generated. The additive is uniformly dispersed to ensure the consistent optical effect and avoid local over-brightness or over-darkness; due to the high refractive index of rare earth ions, light scattering is enhanced, and whiteness is improved; grain size distribution and light scattering are cooperated to form a multi-layer stereoscopic visual effect of bottom-layer framework support, middle-layer transition connection and top-layer fineness and brightness, and the decoration is enhanced.

Description

Technical Field

[0001] This invention relates to the field of building ceramic materials technology, and in particular to a multi-layered three-dimensional white dry granule and its preparation method. Background Technology

[0002] In the architectural ceramics industry, as consumers' demands for the decorative effects of ceramic products continue to rise, ceramic products with unique textures and three-dimensional effects are increasingly favored. Traditional dry ceramic granules have certain limitations in terms of decorative effects and cannot meet the market's demand for highly simulated natural stone, jade, and other materials.

[0003] Currently, most commercially available dry granules can only create relatively simple surface textures or granular feel in terms of three-dimensionality, failing to create rich layering variations and resulting in ceramic products lacking visual depth and realism. In terms of color, ordinary white dry granules are often not pure or white enough, affecting their application in decorative scenarios that demand high whiteness and high quality. Regarding the manufacturing process, existing methods are complex and costly, and the bonding strength between the prepared dry granules and the ceramic glaze needs improvement, easily leading to quality problems such as granule detachment. Some existing technologies simply mix raw materials and fire the dry granules, resulting in uneven granule composition and unstable performance. Patent document CN118655181A provides a multi-layered three-dimensional ceramic tile and its manufacturing process; the multi-layered structure of "screen-printed glaze + replica ink + positioning dry granules" proposed in this patent has been verified to form triple concave-convex textures within a height difference of more than 1 mm. However, this patent does not solve the problems of whiteness >85°, the formulation of the three-dimensional white dry granules themselves, and their compatibility with the overall production line process.

[0004] Therefore, developing a ceramic white dry granule that can overcome the above problems, achieve multi-layered three-dimensional effects, high whiteness, and has a simple preparation process, as well as its preparation method, is of great practical significance. Summary of the Invention

[0005] One of the objectives of this invention is to provide a multi-layered, three-dimensional white dry granule to solve the problems of poor layering and three-dimensionality and low whiteness in ceramic dry granule decoration. The second objective of this invention is to provide a method for preparing multi-layered, three-dimensional white granules.

[0006] The objective of this invention can be achieved through the following technical solutions: Firstly, a multi-layered three-dimensional white dry granule is composed of frit base material and rare earth@calcium phosphate additive in a weight ratio of 100:3-8. Rare earth@calcium phosphate additives are prepared through the following steps: S1. Lanthanum nitrate (La(NO3)3·6H2O) and cerium nitrate (Ce(NO3)3·6H2O) were dissolved in deionized water to obtain a rare earth solution. Citric acid solution was added, and the mixture was stirred at 75-85℃ to obtain a transparent sol. Ammonia was added dropwise until the pH reached 8.5-9.5. After aging for 2 hours, the mixture was washed until neutral to obtain the La / Ce coprecipitate precursor. S2. Dicalcium phosphate (CaHPO4) and nano-Al2O3 are ball-milled and mixed to obtain a porous support; S3. Mix the La / Ce coprecipitated precursor with a porous support, add PEG-400, and spray dry to obtain precursor powder; S4. After the precursor powder is calcined in a reducing atmosphere, it is pulverized by an air jet mill to obtain rare earth@calcium phosphate additive.

[0007] La / Ce co-doped phosphates exhibit strong absorption in the ultraviolet region (300-400 nm) and emit blue light (450 nm), offsetting the yellow tint of the green body. Calcium phosphate reacts with Fe during firing. 2+ A colorless complex phosphate (Fe3(PO4)2) is generated, suppressing red / yellow color development. Nano-Al2O3 bridging promotes the interfacial bonding between the rare earth phase and the dry particle matrix, preventing local aggregation.

[0008] Furthermore, in S1, the molar ratio of lanthanum nitrate, cerium nitrate, and citric acid is 2:1:6.

[0009] Furthermore, in S1, the mass concentration of the rare earth solution is 15%-25%.

[0010] Furthermore, in S1, the mass concentration of the citric acid solution is 25%-35%.

[0011] Furthermore, in S1, the ammonia concentration is 5%-15%.

[0012] Furthermore, in S2, the ball milling medium for dicalcium phosphate and nano-Al2O3 is ethanol, the ball milling speed is 400-600 rpm, and the ball milling time is 2-4 h.

[0013] Furthermore, in S2, the weight ratio of dicalcium phosphate to nano-Al2O3 is 6:1.

[0014] Furthermore, in S3, the weight ratio of La / Ce coprecipitated precursor, porous support, and PEG-400 is 1:3:0.02.

[0015] Furthermore, in S3, the spray drying inlet temperature is 180°C and the outlet temperature is 80°C.

[0016] Furthermore, in S4, the reducing atmosphere consists of nitrogen and hydrogen in a volume ratio of 95:5.

[0017] Furthermore, in S4, the calcination process involves heating at 5℃ / min to 600℃ and holding for 1 hour, then heating to 1100℃ and holding for 2 hours.

[0018] Furthermore, in S4, the D50 of the rare earth@calcium phosphate additive after air jet milling is 1-2 μm.

[0019] Furthermore, the frit base material, by mass fraction, includes the following components: Al₂O₃ 18-21 wt%; K₂O 3-5 wt%; Na₂O 4-10 wt%; CaO 6-8 wt%; ZnO 3-4 wt%; SrO 1.5-2.5 wt%; ZrO₂ 3-4 wt%; B₂O₃ 1-2 wt%; P₂O₅ 0.2-0.4 wt%; Fe₂O₃ ≤ 0.05 wt%; TiO₂ ≤ 0.03 wt%; SiO₂ balance; The method for preparing the frit base material includes the following steps: After mixing the components, heat from room temperature to 700℃ within 40-50 minutes, then continue heating to 1100℃ within 55-65 minutes, and then continue heating to 1450℃ within 70-80 minutes. Hold at this temperature for 20-30 minutes while introducing compressed air at 0.3 MPa. After holding, quench with water to room temperature and grind to 40-60 mesh.

[0020] Furthermore, the gradation of the multi-layered, three-dimensional white dry granules finished product is as follows: Bottom skeleton particles: 60-80 mesh, 40wt% Intermediate transition particle size: 100-150 mesh, 35%; Top layer fine particles: 200-250 mesh, 25%.

[0021] Secondly, a method for preparing multi-layered, three-dimensional white granules includes the following steps: The frit base material and rare earth@calcium phosphate additive are dry-mixed evenly and ground to the corresponding mesh size according to the finished product gradation to obtain multi-layer three-dimensional white dry granules.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention provides a multi-layered, three-dimensional white granule, achieved by adding rare earth element@calcium phosphate as an additive to the frit matrix, utilizing La 3+ Ce 3+The high refractive index of the oxides creates a refractive index difference with the frit matrix (mainly SiO2, with a refractive index of approximately 1.5-1.6), resulting in multiple scattering and refraction of light at the interface. Simultaneously, the synergistic particle size distribution—the differences in particle size between the bottom layer (60-80 mesh), middle layer (100-150 mesh), and top layer (200-250 mesh)—creates a refractive index gradient. The different reflection and refraction paths of light between particles of different sizes produce a visual sense of "depth" (the coarser particles at the bottom reflect more light, the finer particles at the top refract light more, and the middle particles provide a smooth transition). Uniform dispersion of the additives ensures consistent optical effects, avoiding localized over-brightness or under-brightness. The high refractive index of rare earth ions enhances light scattering and improves whiteness (≥90%). The synergistic effect of particle size distribution and light scattering creates a multi-layered, three-dimensional visual effect: a supportive bottom layer, a transitional middle layer, and a delicately brightened top layer, enhancing the decorative appeal.

[0023] 2. Dry granules of different sizes are mixed in a specific ratio (40% at the bottom, 35% in the middle, and 25% at the top), creating a three-dimensional structure through the difference in particle size: the coarse particles at the bottom form a macroscopic framework, reflecting light and enhancing the three-dimensional effect; the fine particles at the top fill the gaps, providing a smooth surface and refracting light to enhance gloss; the middle particles connect the two, eliminating the abruptness of the interface. The graded structure allows light to propagate between particles at different depths, creating a visual hierarchy of "near-real and far-blurred"; the coarse particles enhance mechanical strength (impact resistance), while the fine particles improve surface smoothness, balancing functionality and aesthetics.

[0024] 3. In the preparation of the frit base material, the high-aluminum, high-zinc system in the component ratio inhibits yellowing, while ZrO2 and SrO synergistically enhance whiteness. At low temperatures, adsorbed water, crystal water, and organic impurities (such as trace amounts of organic matter introduced from the raw materials) are removed from the raw materials to prevent rapid evaporation of moisture at high temperatures, which could lead to porosity or cracking of the frit. At medium temperatures, low-melting-point components (such as fluxes like K2O and Na2O) melt first, forming eutectic mixtures with SiO2 and Al2O3, gradually forming a liquid phase and promoting the dispersion and dissolution of high-melting-point components (such as ZrO2 and Al2O3). At high temperatures, high-melting-point components (such as SiO2 and Al2O3) melt extensively under the action of fluxes (K2O and Na2O), forming a homogeneous glassy melt. Simultaneously, functional components such as ZrO2 and SrO are uniformly dispersed in the melt, achieving chemical homogenization. The holding stage completely dissolves any remaining tiny unmelted particles in the melt, promoting uniform component diffusion, eliminating localized component segregation, and forming a homogeneous glassy structure. 0.3 MPa compressed air, used as a stirring medium, breaks up air bubbles in the melt, promoting their escape. Simultaneously, the oxidizing effect of the compressed air inhibits Fe... 2+ (Easily leads to staining) formation (because Fe2O3 content ≤ 0.05wt%, Fe needs to be maintained) 3+(To avoid a yellow / green tint). Gradual heating avoids thermal stress concentration, preventing localized overheating or unmelted particle residue due to excessive temperature differences in the raw materials, ensuring that each component melts gradually in the reaction sequence and reacts fully; eliminating bubbles and component segregation in the melt, increasing the density of the melt, and preventing Fe... 2+ Coloring ensures the high whiteness of the fused ingot. Detailed Implementation

[0025] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0026] The terminology used in the embodiments of this application is for the purpose of describing particular implementations only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the implementations of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0027] It should be understood that in the various embodiments of this application, the sequence number of each process does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the implementation regulations of this application.

[0028] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass described in the embodiments of this application can be a mass unit known in the chemical industry, such as μg, mg, g, or kg.

[0029] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0030] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application are available on the market or can be prepared by existing methods.

[0031] The following description, in conjunction with specific embodiments, provides further details.

[0032] Example 1 This embodiment provides a method for preparing rare earth@calcium phosphate additives, including the following steps: S1. Dissolve 100g La(NO3)3·6H2O and 50g Ce(NO3)3·6H2O in deionized water to obtain a 20% rare earth solution. Dissolve 173g citric acid in deionized water to obtain a 30% citric acid solution. Add the citric acid solution to the rare earth solution and stir at 80℃ to obtain a transparent sol. Add 10% ammonia water dropwise until pH=9, age for 2 hours, and wash until neutral to obtain the La / Ce coprecipitate precursor. S2. Under the condition of ethanol as a medium, calcium hydrogen phosphate and nano-Al2O3 were ball-milled at a weight ratio of 6:1 for 3 hours at a ball milling speed of 500 rpm to obtain a porous carrier. S3. Mix 100g of La / Ce coprecipitate precursor with 300g of porous support, add 2g of PEG-400, and spray dry to obtain precursor powder. The spray drying inlet temperature is 180℃ and the outlet temperature is 80℃. S4. Precursor powder is placed in a reducing atmosphere (V N2 :V H2 Rare earth@calcium phosphate additive with a D50 of 1-2 μm was obtained by heating to 600℃ at 5℃ / min and holding for 1h, then heating to 1100℃ and holding for 2h.

[0033] Example 2 This embodiment provides a method for preparing a frit base material, comprising the following components: The following components were mixed evenly: Al2O3 20wt%; K2O 4wt%; Na2O 5wt%; CaO 7wt%; ZnO 3wt%; SrO 2wt%; ZrO2 4wt%; B2O3 1.5wt%; P2O5 0.3wt%; Fe2O3 0.03wt%; TiO2 0.01wt%; and SiO2 as the balance. The mixture was heated from room temperature to 700℃ over 45 minutes, then further heated to 1100℃ over 60 minutes, and then further heated to 1450℃ over 75 minutes. The mixture was held at this temperature for 25 minutes while purging with 0.3MPa compressed air. After the holding period, the mixture was quenched in water to room temperature and then ground to 50 mesh.

[0034] Example 3 This embodiment provides a method for preparing multi-layered, three-dimensional white granules, including the following steps: The frit base material prepared in Example 2 and the rare earth@calcium phosphate additive prepared in Example 1 were mixed evenly at a weight ratio of 100:5, and divided into three parts according to a weight ratio of 40wt%, 35wt%, and 25wt%. The 40wt% mixture was ground to a mesh size of 70±5 mesh and used as the bottom skeleton particles, the 35wt% mixture was ground to a mesh size of 130±5 mesh and used as the intermediate transition particles, and the 25wt% mixture was ground to a mesh size of 220±5 mesh and used as the top fine particles.

[0035] Example 4 This embodiment provides a method for preparing multi-layered three-dimensional white dry granules. The only difference from Embodiment 3 is that the frit base material prepared in Embodiment 2 and the rare earth@calcium phosphate additive prepared in Embodiment 1 are mixed evenly at a weight ratio of 100:3.

[0036] Example 5 This embodiment provides a method for preparing multi-layered three-dimensional white dry granules. The only difference from Embodiment 3 is that the frit base material prepared in Embodiment 2 and the rare earth@calcium phosphate additive prepared in Embodiment 1 are mixed evenly at a weight ratio of 100:8.

[0037] Comparative Example 1 This comparative example provides a method for preparing a calcium phosphate additive, comprising the following steps: S1. Under the condition of ethanol as a medium, calcium hydrogen phosphate and nano-Al2O3 were ball-milled at a weight ratio of 6:1 for 3 hours at a ball milling speed of 500 rpm to obtain a porous carrier. 2g of PEG-400 was added to 2.300g of porous carrier and spray-dried to obtain precursor powder. The spray drying inlet temperature was 180℃ and the outlet temperature was 80℃. S3. Precursor powder is placed in a reducing atmosphere (V). N2 :V H2 The calcium phosphate additive with a D50 of 1-2 μm was obtained by heating to 600℃ at 5℃ / min and holding for 1 hour, then heating to 1100℃ and holding for 2 hours, followed by calcination.

[0038] Comparative Example 2 This comparative example provides a method for preparing rare earth additives, including the following steps: S1. Dissolve 100g La(NO3)3·6H2O and 50g Ce(NO3)3·6H2O in deionized water to obtain a 20% rare earth solution. Dissolve 173g citric acid in deionized water to obtain a 30% citric acid solution. Add the citric acid solution to the rare earth solution and stir at 80℃ to obtain a transparent sol. Add 10% ammonia water dropwise until pH=9, age for 2 hours, and wash until neutral to obtain the La / Ce coprecipitate precursor. S3.100g La / Ce coprecipitate precursor was mixed with 2g PEG-400 and spray-dried to obtain precursor powder. The spray drying inlet temperature was 180℃ and the outlet temperature was 80℃. S4. Precursor powder is placed in a reducing atmosphere (V N2 :V H2 The rare earth additive with a D50 of 1-2 μm was obtained by heating to 600℃ at 5℃ / min and holding for 1h, then heating to 1100℃ and holding for 2h, followed by calcination.

[0039] Comparative Example 3 The preparation method of the frit base material provided in this comparative example differs from that in Example 2 in that after the components are mixed evenly, they are heated at a uniform rate to 1450°C within 180 minutes, held at that temperature for 25 minutes, and 0.3 MPa compressed air is introduced during the holding period. After the holding period, the material is quenched in water to room temperature and then ground to 50 mesh.

[0040] Comparative Example 4 The method for preparing the frit base material provided in this comparative example differs from that in Example 2 in that 0.3 MPa compressed air is not introduced during the heat preservation stage.

[0041] Comparative Example 5 This comparative example provides a method for preparing multi-layered three-dimensional white dry granules. The only difference from Example 3 is that the rare earth@calcium phosphate additive prepared in Example 1 is replaced with an equal amount of calcium phosphate additive prepared in Comparative Example 1.

[0042] Comparative Example 6 This comparative example provides a method for preparing multi-layered three-dimensional white dry granules. The only difference from Example 3 is that the rare earth@calcium phosphate additive prepared in Example 1 is replaced with an equal amount of rare earth additive prepared in Comparative Example 2.

[0043] Comparative Example 7 This comparative example provides a method for preparing multi-layered three-dimensional white dry granules. The only difference from Example 3 is that the frit base material prepared in Example 2 is replaced with an equal amount of the frit base material prepared in Comparative Example 3.

[0044] Comparative Example 8 This comparative example provides a method for preparing multi-layered three-dimensional white dry granules. The only difference from Example 3 is that the frit base material prepared in Example 2 is replaced with an equal amount of the frit base material prepared in Comparative Example 4.

[0045] Comparative Example 9 This comparative example provides a method for preparing multi-layered three-dimensional white dry granules. The only difference from Example 3 is that the frit base material prepared in Example 2 and the rare earth@calcium phosphate additive prepared in Example 1 are mixed evenly at a weight ratio of 100:5 and then ground until the uniform mesh size is 150±5 mesh.

[0046] The white dry granules prepared in Examples 3-5 and Comparative Examples 5-9 were applied to the surface of ceramic tile bodies, and after glazing and firing, performance tests were conducted. The whiteness value (W) was measured using a whiteness meter; the gloss difference (ΔGU) between the top and bottom layers was measured using a 60° gloss meter; and the hardness was tested using a Mohs hardness tester. The test results are shown in Table 1.

[0047] Table 1 The test results above show that by adding rare earth@calcium phosphate as an additive to the frit matrix, the present invention improves the whiteness of dry particles in coordination with the frit matrix composition ratio. At the same time, the particle size distribution and light scattering work together to form a multi-layered three-dimensional visual effect of "bottom layer skeleton support, middle layer transition and connection, and top layer delicate brightening", which enhances the decorative effect.

[0048] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0049] The above-disclosed embodiments are merely a few specific examples of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A multi-layered, three-dimensional white dried granules, characterized in that, It is composed of frit base material and rare earth@calcium phosphate additive; Rare earth@calcium phosphate additives are prepared through the following steps: S1. Lanthanum nitrate and cerium nitrate are dissolved in deionized water to obtain a rare earth solution. Citric acid solution is added, and the mixture is stirred evenly at 75-85℃. The pH is adjusted to 8.5-9.5 with ammonia water, and the mixture is aged to obtain the La / Ce coprecipitate precursor. S2. Dicalcium phosphate and nano-Al2O3 are ball-milled and mixed to obtain a porous support; S3. Mix the La / Ce coprecipitated precursor with a porous support, add PEG-400, and spray dry to obtain precursor powder; S4. After the precursor powder is calcined in a reducing atmosphere, it is pulverized by an air jet mill to obtain rare earth@calcium phosphate additive.

2. The multi-layered three-dimensional white granules according to claim 1, characterized in that, The weight ratio of the frit base material to rare earth@calcium phosphate additive is 100:3-8.

3. The multi-layered three-dimensional white granules according to claim 1, characterized in that, In S1, the molar ratio of lanthanum nitrate, cerium nitrate, and citric acid is 2:1:

6.

4. The multi-layered three-dimensional white granules according to claim 1, characterized in that, In S1, the mass concentration of the rare earth solution is 15%-25%; the mass concentration of the citric acid solution is 25%-35%; and the concentration of ammonia is 5%-15%.

5. The multi-layered three-dimensional white granules according to claim 1, characterized in that, In S2, calcium hydrogen phosphate and nano The weight ratio is 6:

1.

6. The multi-layered three-dimensional white granules according to claim 1, characterized in that, In S3, the weight ratio of La / Ce coprecipitated precursor, porous support, and PEG-400 is 1:3:0.

02.

7. The multi-layered three-dimensional white granules according to claim 1, characterized in that, In S4, the reducing atmosphere consists of nitrogen and hydrogen in a volume ratio of 95:

5.

8. The multi-layered three-dimensional white granules according to claim 1, characterized in that, The frit base material, by mass fraction, comprises the following components: Al₂O₃ 18-21 wt%; K₂O 3-5 wt%; Na₂O 4-10 wt%; CaO 6-8 wt%; ZnO 3-4 wt%; SrO 1.5-2.5 wt%; ZrO₂ 3-4 wt%; B₂O₃ 1-2 wt%; P₂O₅ 0.2-0.4 wt%; Fe₂O₃ ≤0.05 wt%; TiO₂ ≤0.03 wt%; SiO₂ balance; The method for preparing the frit base material includes the following steps: After mixing the components, heat from room temperature to 700℃ within 40-50 minutes, then continue heating to 1100℃ within 55-65 minutes, and then continue heating to 1450℃ within 70-80 minutes. Hold at this temperature for 20-30 minutes while introducing compressed air at 0.3 MPa. After holding, quench with water to room temperature and grind to 40-60 mesh.

9. The multi-layered three-dimensional white granules according to claim 1, characterized in that, The finished product gradation of multi-layered, three-dimensional white dry granules is as follows: Bottom skeleton particles: 60-80 mesh, 40wt% Intermediate transition particle size: 100-150 mesh, 35%; Top layer fine particles: 200-250 mesh, 25%.

10. A method for preparing multi-layered three-dimensional effect white granules, used to prepare the multi-layered three-dimensional effect white granules according to any one of claims 1-9, characterized in that, Includes the following steps: The frit base material and rare earth@calcium phosphate additive are dry-mixed evenly and ground to the corresponding mesh size according to the finished product gradation to obtain multi-layer three-dimensional white dry granules.

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