Fritted glaze, fritted glaze layer, super flat polished ceramic tile and preparation method thereof

Abstract

This invention relates to the field of ceramic tile technology, and particularly to a fused glaze, a fused glaze layer, an ultra-flat polished ceramic tile, and a method for preparing the same. The fused glaze comprises transparent dry granules and an ultra-flat glaze in a mass ratio of 1:(1.9-2.1). The raw materials of the ultra-flat glaze, by weight, include: 5-7 parts of sodium feldspar, 18-24 parts of potassium feldspar, 10-16 parts of kaolin, 5-10 parts of quartz, 8-10 parts of dolomite, 6-9 parts of wollastonite, 5.5-6.5 parts of calcined kaolin, 4-7 parts of calcined talc, 14-17 parts of nano-barium sulfate, and 8-10 parts of zinc oxide; the nano-barium sulfate has a particle size D97 of 100-150 nm. The fused glaze, with its combination of transparent dry granules and ultra-flat glaze, exhibits excellent wear resistance and stain resistance after firing, and also possesses strong transparency and good flatness.

Description

Technical Field

[0001] This invention relates to the field of ceramic tile technology, and in particular to a fused glaze, a fused glaze layer, an ultra-flat polished ceramic tile, and a method for preparing the same. Background Technology

[0002] Existing fully polished glazed ceramic tiles are manufactured by first applying a protective glaze to the inkjet pattern surface, followed by a polishing glaze. However, due to the insufficient wear resistance of both the protective and polishing glazes, they are prone to scratches during use. Furthermore, differences in the thermal expansion compatibility between the multiple glaze layers often result in unsatisfactory surface smoothness. A "water ripple" phenomenon is commonly observed before and after polishing. This uneven surface leads to uneven light reflection, causing pattern distortion and disrupting the overall visual continuity, failing to achieve a perfectly smooth surface. This issue is particularly noticeable when large tiles are laid with close joints, thus affecting the overall aesthetics. Current attempts to address these problems by increasing the amount of glaze applied and the polishing depth have not yielded significant improvements in smoothness and require increased raw material usage and energy costs, which contradicts the goal of resource conservation.

[0003] It is evident that existing technologies still need improvement and enhancement. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a fused glaze, a fused glaze layer, an ultra-flat polished ceramic tile and a method for preparing the same, with the aim of improving the overall surface flatness of ceramic tiles.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: The first aspect of the present invention provides a fused glaze comprising transparent dry granules and an ultra-flat glaze in a mass ratio of 1:(1.9 to 2.1); The transparent dry granules comprise the following chemical composition by mass fraction: SiO2 63.0%–67.5%, Al2O3 6.0%–9.5%, CaO 12.5%–16.5%, MgO 1.0%–2.8%, K2O 3.0%–4.0%, BaO 3.0%–6.3%, SrO 1.4%–2.5%, with the remainder being loss on ignition and impurities; The raw materials of the ultra-flat glaze, by weight, include: 5-7 parts of sodium feldspar, 18-24 parts of potassium feldspar, 10-16 parts of kaolin, 5-10 parts of quartz, 8-10 parts of dolomite, 6-9 parts of wollastonite, 5.5-6.5 parts of calcined kaolin, 4-7 parts of calcined talc, 14-17 parts of nano-barium sulfate, and 8-10 parts of calcined zinc oxide. The particle size D97 of the nano-barium sulfate is 100-150 nm.

[0006] The fused glaze, wherein the ultra-flat glaze comprises the following chemical composition by mass fraction: SiO2 39.5%–44.5%, Al2O3 11.5%–14.2%, CaO 5.7%–7.0%, MgO 3.4%–4.3%, K2O 2.3%–3.2%, Na2O 0.85%–1.1%, SO3 4.5%–6.0%, BaO 9.0%–11.5%, ZnO 7.7%–10.2%, with the remainder being loss on ignition and impurities.

[0007] The fused glaze, wherein the particle size D97 of the raw material in the fused glaze is 20-30µm.

[0008] The fused glaze, wherein the preparation method of the fused glaze includes the following steps: mixing the transparent dry granules, ultra-flat glaze, water, thickener and dispersant, and then ball milling, sieving and aging to obtain the fused glaze.

[0009] A second aspect of the present invention provides a fused glaze layer, which is fired from the fused glaze as described above, wherein the proportion of amorphous phase in the fused glaze layer is >99 wt.%.

[0010] A third aspect of the present invention provides an ultra-flat polished ceramic tile, comprising a body layer, a surface glaze layer, and a fused glaze layer as described above, arranged from bottom to top.

[0011] The ultra-flat polished ceramic tile, wherein the raw material for preparing the glaze layer includes a glaze, which comprises the following chemical components by mass fraction: SiO2 55.3%–61.3%, Al2O3 28.5%–33%, CaO 1.0%–1.2%, MgO 0.7%–0.9%, K2O 1.5%–1.9%, Na2O 3.7%–4.7%, with the remainder being loss on ignition and impurities.

[0012] The ultra-flat polished ceramic tile, wherein an inkjet pattern layer is provided between the surface glaze layer and the fused glaze layer.

[0013] A fourth aspect of this invention provides a method for preparing ultra-flat polished ceramic tiles, comprising the following steps: S01. Apply a surface glaze to the body layer so that a surface glaze layer is obtained after firing; S02. Apply a fused glaze to obtain a fused glaze layer after firing; S03. Firing and polishing to obtain ultra-flat polished ceramic tiles as described above.

[0014] The fifth aspect of this invention provides a method for preparing ultra-flat polished ceramic tiles, comprising the following steps: S01. Apply a surface glaze to the body layer so that a surface glaze layer is obtained after firing; S02. Inkjet print pattern to obtain inkjet pattern layer after firing; S03. Apply a fused glaze to obtain a fused glaze layer after firing; S04. Firing and polishing to obtain ultra-flat polished ceramic tiles as described above.

[0015] Beneficial Effects: This invention provides a fused glaze comprising transparent dry granules and an ultra-flat glaze. The transparent dry granules account for more than 30% of the fused glaze, filling the entire glaze layer with a high proportion, thereby reducing the reaction intensity of the glaze layer and decreasing the formation of bubbles and blistering. Simultaneously, the uniform distribution of the transparent dry granules in the ultra-flat glaze results in a relatively low coefficient of thermal expansion of the glass melt, effectively adjusting the glaze layer's deformation and improving overall flatness. Furthermore, the high proportion of SiO2 in the transparent dry granules promotes the formation of more glass networks in the glaze layer, eliminating the possibility of crystal formation and significantly improving the glaze layer's transparency. Attached Figure Description

[0016] Figure 1 The image shows the XRD phase analysis of the fused glaze layer in the ultra-flat polished ceramic tile prepared in Example 1. Detailed Implementation

[0017] This invention provides a fused glaze, a fused glaze layer, an ultra-flat polished ceramic tile, and a method for preparing the same. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0018] The first aspect of the present invention provides a fused glaze comprising transparent dry granules and an ultra-flat glaze in a mass ratio of 1:(1.9 to 2.1); The transparent dry granules comprise the following chemical composition by mass fraction: SiO2 63.0%–67.5%, Al2O3 6.0%–9.5%, CaO 12.5%–16.5%, MgO 1.0%–2.8%, K2O 3.0%–4.0%, BaO 3.0%–6.3%, SrO 1.4%–2.5%, with the remainder being loss on ignition and impurities; The raw materials of the ultra-flat glaze, by weight, include: 5-7 parts sodium feldspar, 18-24 parts potassium feldspar, 10-16 parts kaolin, 5-10 parts quartz, 8-10 parts dolomite, 6-9 parts wollastonite, 5.5-6.5 parts calcined kaolin, 4-7 parts calcined talc, 14-17 parts nano barium sulfate, and 8-10 parts calcined zinc oxide.

[0019] In the above formula, transparent dry granules account for more than 30% of the entire fused glaze, which can effectively reduce the reaction intensity of the glaze layer, thereby reducing the formation of bubbles and blistering. Transparent dry granules also result in a relatively low coefficient of thermal expansion of the glass melt, effectively adjusting the deformation of the glaze layer and improving overall smoothness. Furthermore, transparent dry granules can effectively optimize the chemical structure of the entire glaze layer, improving its overall performance. Specifically, the high proportion of SiO2 in the transparent dry granules promotes the formation of more glass networks in the glaze layer, eliminating the possibility of crystal formation and greatly improving the transparency of the glaze layer. The Al2O3 contained in the transparent dry granules can form dense Al-O-Si bonds, significantly increasing the density of the glaze layer, thereby enhancing its acid and alkali resistance and wear resistance. If the Al2O3 content is too low, it cannot fill the gaps in the glaze glass network, resulting in a loose and non-dense structure, making it easily eroded and dissolved by acids and alkalis; if the Al2O3 content is too high, it will increase the firing temperature of the glaze layer, increase the exhaust volume, leading to more pinholes on the glaze surface, which will reduce density and acid and alkali resistance.

[0020] In the raw materials of the aforementioned ultra-flat glaze, potassium feldspar and sodium feldspar act as strong fluxes, initially melting the glaze at low temperatures. Combined with fluxes such as dolomite and wollastonite, the entire glaze layer gradually melts. Simultaneously, dolomite decomposes at low temperatures, opening the pores of the glaze layer and promoting venting, which is beneficial for forming a transparent glass melt. Meanwhile, nano-barium sulfate melts and decomposes at high temperatures, increasing venting at high temperatures. The resulting barium oxide acts as a high-temperature flux for the glaze layer and reduces the viscosity of the glaze melt, ensuring smooth venting and promoting the precipitation of fine bubbles in the glass phase, thus better enhancing the texture and transparency of the glaze layer.

[0021] Meanwhile, compared with ordinary barium sulfate, nano-barium sulfate has a larger specific surface area due to its nano-sized particles, which improves its compatibility with other raw materials and can enhance the transparency, strength, toughness and wear resistance of the glaze.

[0022] When transparent dry granules are combined with ultra-flat glaze, the content of barium oxide in the system is reduced, effectively avoiding the tendency to be induced by corrosion due to its large ionic radius and low bond strength. At the same time, maintaining a certain content of barium oxide can prevent the glass network from crystallizing. Its low bond strength can effectively promote melting and reduce viscosity, which is conducive to forming a smooth surface and improving anti-fouling properties. Transparent dry granules contain a high content of calcium oxide, which can increase the overall calcium oxide content, thereby enhancing the high-temperature melting effect. It can also reduce high-temperature viscosity, allowing the glaze melt to spread more fully and reducing glaze shrinkage defects. In addition, calcium oxide is a strong alkaline oxide, which is beneficial to improving the alkali resistance of the glaze surface.

[0023] In addition, the amount of transparent dry granules should not be too much. This is because the use of transparent dry granules in combination with ultra-flat glaze reduces the overall zinc oxide ratio. Zinc oxide ions have a small radius and high field strength, which can easily damage the glass network and induce crystallization, resulting in poor transparency of the glaze layer. At the same time, zinc oxide is more likely to react with acid, causing insufficient acid resistance. Therefore, by controlling the amount of transparent dry granules, the content of zinc oxide can be controlled to ensure the transparency and acid resistance of the subsequent glaze layer.

[0024] In molten glazes, alkali metals K₂O and NaO are easily affected by H₂O. + OH - The addition of transparent dry granules can dissolve and erode alkali metals such as K2O and NaO, effectively avoiding their leaching risk. It has good acid and alkali resistance, and the sufficient amount of calcium oxide in the transparent dry granules can also increase the overall calcium oxide content of the glaze layer, thereby improving alkali resistance.

[0025] Preferably, the particle size D97 of the nano-barium sulfate is 100-150 nm. If the particle size of the nano-barium sulfate is too small, it is easy to melt and decompose, resulting in venting in the low-temperature zone. The lack of high-temperature venting in the glaze layer will cause the pores to close prematurely, forming microbubbles and affecting transparency. If the particle size of the nano-barium sulfate is too large, it will not participate in the melting reaction, but will exist as crystals, which is also detrimental to transparency.

[0026] Preferably, in the fused glaze, the particle size D97 of the raw material is 20-30µm.

[0027] Preferably, the ultra-flat glaze comprises the following chemical composition by mass fraction: SiO2 39.5%–44.5%, Al2O3 11.5%–14.2%, CaO 5.7%–7.0%, MgO 3.4%–4.3%, K2O 2.3%–3.2%, Na2O 0.85%–1.1%, SO3 4.5%–6.0%, BaO 9.0%–11.5%, ZnO 7.7%–10.2%, with the remainder being loss on ignition and impurities.

[0028] Preferably, the preparation method of the fused glaze includes the following steps: mixing the transparent dry granules, ultra-flat glaze, water, thickener and dispersant, and then ball milling, sieving and aging to obtain the fused glaze.

[0029] A second aspect of the present invention provides a fused glaze layer, which is fired from the fused glaze as described above, wherein the proportion of amorphous phase in the fused glaze layer is >99 wt.%.

[0030] A third aspect of the present invention provides an ultra-flat polished ceramic tile, comprising a body layer, a surface glaze layer, and a fused glaze layer as described above, arranged from bottom to top.

[0031] Preferably, the raw materials for preparing the surface glaze layer include a surface glaze, which comprises the following chemical components by mass fraction: SiO2 55.3%–61.3%, Al2O3 28.5%–33%, CaO 1.0%–1.2%, MgO 0.7%–0.9%, K2O 1.5%–1.9%, Na2O 3.7%–4.7%, with the remainder being loss on ignition and impurities.

[0032] Preferably, an inkjet pattern layer is provided between the surface glaze layer and the fused glaze layer.

[0033] The present invention will be further illustrated by the following examples and comparative examples.

[0034] Example 1 A type of ultra-flat polished ceramic tile, comprising, from bottom to top, a body layer, a surface glaze layer, and a fused glaze layer; The raw material for preparing the fused glaze layer is fused glaze, which is composed of transparent dry granules and ultra-flat glaze in a mass ratio of 1:2. The preparation process of the fused glaze, by weight, includes the following steps: mixing 100 parts of transparent dry granules, 200 parts of ultra-flat glaze, 100 parts of water, 0.35 parts of thickener (methylcellulose), and 0.9 parts of dispersant (sodium tripolyphosphate), followed by ball milling, sieving, and aging to obtain the fused glaze; the specific gravity of the fused glaze is 1.86 g / cm³. 3 ; The transparent dry granules are composed of the following chemical components by mass fraction: SiO2 65.21%, Al2O3 7.54%, CaO 14.71%, MgO 1.85%, K2O 3.45%, BaO 4.68%, SrO 1.99%, with a loss on ignition and impurities of 0.57%. The raw materials for preparing the transparent dry granules, by weight, are: potassium feldspar 24 parts, kaolin 6.5 parts, quartz 31 parts, limestone 13 parts, wollastonite 12.5 parts, calcined talc 5 parts, barium carbonate 5.5 parts, and strontium carbonate 2.5 parts. The preparation method of the transparent dry granules includes the following steps: mixing the above-mentioned raw materials for the transparent dry granules, calcining and melting them at 1400 ℃ to obtain a glass melt, cooling the molten glass melt through water-cooled metal rollers, and crushing it to obtain the above-mentioned transparent dry granules. The ultra-flat glaze is composed of the following chemical components by mass fraction: SiO2 42.1%, Al2O3 13.12%, CaO 6.67%, MgO 4.04%, K2O 2.72%, Na2O 0.91%, SO3 4.7%, BaO 10.4%, ZnO 8.93%, with a loss on ignition and impurities of 6.41%. By weight, the raw materials for the ultra-flat glaze are: 6 parts sodium feldspar, 20 parts potassium feldspar, 13 parts kaolin, 8 parts quartz, 9 parts dolomite, 7.5 parts wollastonite, 7 parts calcined kaolin, 5.5 parts calcined talc, 15 parts nano-barium sulfate, and 9 parts calcined zinc oxide. The ultra-flat glaze is obtained by crushing and mixing the above raw materials according to the specified proportions. The surface glaze is composed of the following chemical components by mass fraction: SiO2 58.31%, Al2O3 30.75%, CaO 1.09%, MgO 0.81%, K2O 1.72%, Na2O 4.23%, with a loss on ignition and impurities of 3.09%. By weight, the raw materials for the surface glaze are: potassium feldspar 8 parts, sodium feldspar 13 parts, kaolin 10.5 parts, quartz 27 parts, wollastonite 2 parts, nepheline 18 parts, calcined kaolin 5.5 parts, calcined talc 2 parts, and calcined alumina 14 parts. The preparation method of the surface glaze includes the following steps: mixing 100 parts of the raw materials for the surface glaze, 38 parts of water, 0.15 parts of thickener (methylcellulose), and 0.35 parts of dispersant (sodium tripolyphosphate), followed by ball milling, sieving, and aging to obtain the surface glaze. The specific gravity of the surface glaze is 1.87 g / cm³. 3 ; This embodiment provides a method for preparing ultra-flat polished ceramic tiles, comprising the following steps: S01. Obtain a green body layer with a moisture content of less than 0.3% by mass; S02. Apply a top glaze to the surface of the body layer to form a top glaze layer after firing. The amount of top glaze applied is 460g / m². 2 ; S03. Apply a fusion glaze to the surface of the glaze layer to form a fusion glaze layer after firing. The amount of fusion glaze applied is 700 g / m². 2 ; S04. A super-flat polished ceramic tile is produced by firing and polishing in a kiln with a maximum temperature of 1150℃.

[0035] Figure 1 The image shows the XRD phase analysis of the fused glaze layer in the ultra-flat polished ceramic tile prepared in Example 1. The image reveals only broadened diffuse peaks in the X-ray diffraction pattern, indicating that the fused glaze layer prepared in this invention has almost no crystalline phase precipitation, with a very high proportion of amorphous phase, and is predominantly composed of a uniform and stable glassy phase structure. Software analysis shows that the amorphous phase proportion in the fused glaze layer is >99 wt.%.

[0036] Example 2 An ultra-flat polished ceramic tile, which differs from Example 1 in that: The transparent dry granules are composed of the following chemical components by mass fraction: SiO2 63.66%, Al2O3 8.97%, CaO 12.92%, MgO 2.58%, K2O 3.73%, BaO 6.00%, SrO 1.55%, with a loss on ignition and impurities of 0.59%. The raw materials for preparing the transparent dry granules, by weight, are: potassium feldspar 26 parts, kaolin 9 parts, quartz 26.5 parts, limestone 11 parts, wollastonite 11.5 parts, calcined talc 7 parts, barium carbonate 7 parts, and strontium carbonate 2 parts. The ultra-flat glaze is composed of the following chemical components by mass fraction: SiO2 39.66%, Al2O3 13.73%, CaO 5.94%, MgO 3.53%, K2O 3.12%, Na2O 0.91%, SO3 5.78%, BaO 11.18%, ZnO 7.92%, and loss on ignition and impurities 8.23%. By weight, the raw materials of the ultra-flat glaze are: sodium feldspar 5 parts, potassium feldspar 24 parts, kaolin 15.5 parts, quartz 5 parts, dolomite 10 parts, wollastonite 6 parts, calcined kaolin 5.5 parts, calcined talc 4 parts, nano barium sulfate 17 parts, and calcined zinc oxide 8 parts. The surface glaze is composed of the following chemical components by mass fraction: SiO2 55.8%, Al2O3 32.73%, CaO 1.01%, MgO 0.87%, K2O 1.87%, Na2O 3.74%, loss on ignition and impurities 3.98%; by weight, the raw materials of the surface glaze are: potassium feldspar 10 parts, sodium feldspar 15 parts, kaolin 8.5 parts, quartz 23 parts, wollastonite 3 parts, nepheline 15 parts, calcined kaolin 3.5 parts, calcined talc 4 parts, and calcined alumina 18 parts.

[0037] Example 3 An ultra-flat polished ceramic tile, which differs from Example 1 in that: The transparent dry granules are composed of the following chemical components by mass fraction: SiO2 67.03%, Al2O3 6.51%, CaO 15.92%, MgO 1.11%, K2O 3.16%, BaO 3.44%, SrO 2.33%, with a loss on ignition and impurities of 0.50%. The raw materials for the transparent dry granules, by weight, include: potassium feldspar 22 parts, kaolin 5 parts, quartz 35.5 parts, limestone 14 parts, wollastonite 13.5 parts, calcined talc 3 parts, barium carbonate 4 parts, and strontium carbonate 3 parts. The ultra-flat glaze is composed of the following chemical components by mass fraction: SiO2 43.9%, Al2O3 11.61%, CaO 6.78%, MgO 4.09%, K2O 2.34%, Na2O 1.04%, SO3 4.76%, BaO 9.2%, ZnO 9.9%, and loss on ignition and impurities 6.38%. The raw materials of the ultra-flat glaze, by weight, include: sodium feldspar 7 parts, potassium feldspar 18 parts, kaolin 10 parts, quartz 10 parts, dolomite 8 parts, wollastonite 9 parts, calcined kaolin 7 parts, calcined talc 7 parts, nano barium sulfate 14 parts, and calcined zinc oxide 10 parts. The surface glaze is composed of the following chemical components by mass fraction: SiO2 61.07%, Al2O3 28.66%, CaO 1.09%, MgO 0.72%, K2O 1.51%, Na2O 4.57%, loss on ignition and impurities 2.38%; the raw materials of the surface glaze by weight include: potassium feldspar 6 parts, sodium feldspar 10 parts, kaolin 12 parts, quartz 31 parts, wollastonite 1 part, nepheline 21 parts, calcined kaolin 7.5 parts, calcined talc powder 1 part, and calcined alumina 10.5 parts.

[0038] Comparative Example 1 A ceramic tile that differs from Example 1 in that: In this comparative example of fused glaze, the mass ratio of transparent dry particles to ultra-flat glaze is 1:4, and the rest is the same as in Example 1.

[0039] Comparative Example 2 This comparative example provides a ceramic tile that differs from Example 1 in that: In this comparative example of fused glaze, the mass ratio of transparent dry particles to ultra-flat glaze is 2:1, and the rest is the same as in Example 1.

[0040] Comparative Example 3 A ceramic tile that differs from Example 1 in that: In the ultra-flat glaze of this comparative example, the particle size D97 of nano-barium sulfate is 250 nm.

[0041] Comparative Example 4 A ceramic tile that differs from Example 1 in that: In the ultra-flat glaze of this comparative example, the particle size D97 of nano-barium sulfate is 50 nm.

[0042] Comparative Example 5 A ceramic tile that differs from Example 1 in that: The ultra-flat glaze does not contain nano-barium sulfate.

[0043] Comparative Example 6 A ceramic tile that differs from Example 1 in that: The amount of dolomite used in the ultra-flat glaze is 4 parts.

[0044] The ultra-flat polished ceramic tiles prepared in the above embodiments and the ceramic tiles prepared in the comparative examples were subjected to performance tests, specifically testing their wear resistance, stain resistance, transparency, and surface quality. Among them, the surface wear resistance was tested using the method in GB / T3810.7, and the surface stain resistance and surface quality were tested using the method in GB / T3810.14-2016. The transparency was tested using the method of GB / T2680-94 for determining the direct transmittance of sunlight in architectural glass. After the glaze slurry was made into glaze sheets and fired (1 mm), the direct transmittance of sunlight was measured. The specific test results are shown in Table 1.

[0045] Table 1

[0046] The results above show that the ultra-flat polished ceramic tiles of Examples 1-3 have excellent wear resistance and stain resistance, high transparency, strong permeability, and good flatness.

[0047] In Comparative Example 1, all properties of the glaze layer decreased. This is because when the proportion of transparent dry particles in the fused glaze is too small and the proportion of ultra-flat glaze is too large, it will lead to melting at too low a temperature, easy precipitation of crystals, insufficient transparency of the glaze layer, and easy over-firing, resulting in poor overall flatness.

[0048] In Comparative Example 2, all properties of the glaze layer decreased. This was because when the proportion of transparent dry particles in the fused glaze was too large and the proportion of ultra-flat glaze was too large, the melting effect was not ideal, the low-temperature viscosity was high, the low-temperature venting was poor, and there was a lack of more barium sulfate to decompose and vent at high temperatures, which ultimately resulted in poor transparency. At the same time, the lack of filling with fine glaze particles resulted in poor surface stain resistance and wear resistance.

[0049] In Comparative Example 3, all properties of the glaze layer decreased. This is because when the particle size of the nano-barium sulfate in the ultra-flat glaze is too large, it cannot participate in the melting reaction and easily forms crystals, thus affecting the transparency.

[0050] In Comparative Example 4, all properties of the glaze layer decreased. This is because when the particle size of the nano-barium sulfate in the ultra-flat glaze is too small, it is easy to melt and decompose in the low-temperature zone to release gas. The lack of high-temperature gas release will cause the pores to close prematurely, forming micro-bubbles that affect the transparency, resulting in poor stain resistance and wear resistance of the glaze layer surface after polishing.

[0051] In Comparative Example 5, the ultra-flat glaze did not contain nano-barium sulfate. During high-temperature melting, the venting performance deteriorated, resulting in poor venting and a large number of fine bubbles. This also affected the transparency and led to poor stain resistance and wear resistance of the glaze surface after polishing.

[0052] In Comparative Example 6, the dolomite content in the ultra-flat glaze was low, resulting in poor glaze air removal and the formation of fine bubbles, which affected the transparency.

[0053] It is understood that those skilled in the art can make equivalent substitutions or modifications to the technical solution and inventive concept of the present invention, and all such substitutions or modifications should fall within the protection scope of the appended claims.

Claims

1. A fused glaze, characterized in that, This includes transparent dry granules and ultra-flat glazes with a mass ratio of 1:(1.9 to 2.1); The transparent dry granules comprise the following chemical composition by mass fraction: SiO2 63.0%–67.5%, Al2O3 6.0%–9.5%, CaO 12.5%–16.5%, MgO 1.0%–2.8%, K2O 3.0%–4.0%, BaO 3.0%–6.3%, SrO 1.4%–2.5%, with the remainder being loss on ignition and impurities; The raw materials of the ultra-flat glaze, by weight, include: 5-7 parts of sodium feldspar, 18-24 parts of potassium feldspar, 10-16 parts of kaolin, 5-10 parts of quartz, 8-10 parts of dolomite, 6-9 parts of wollastonite, 5.5-6.5 parts of calcined kaolin, 4-7 parts of calcined talc, 14-17 parts of nano-barium sulfate, and 8-10 parts of calcined zinc oxide. The particle size D97 of the nano-barium sulfate is 100-150 nm.

2. The fused glaze according to claim 1, characterized in that, The ultra-flat glaze comprises the following chemical components by mass fraction: SiO2 39.5%–44.5%, Al2O3 11.5%–14.2%, CaO 5.7%–7.0%, MgO 3.4%–4.3%, K2O 2.3%–3.2%, Na2O 0.85%–1.1%, SO3 4.5%–6.0%, BaO 9.0%–11.5%, ZnO 7.7%–10.2%, with the remainder being loss on ignition and impurities.

3. The fused glaze according to claim 1, characterized in that, In the fused glaze, the particle size D97 of the raw material is 20-30µm.

4. The fused glaze according to claim 1, characterized in that, The preparation method of the fused glaze includes the following steps: mixing the transparent dry granules, ultra-flat glaze, water, thickener and dispersant, and then ball milling, sieving and aging to obtain the fused glaze.

5. A fused glaze layer, characterized in that, It is made by firing the fusion glaze according to any one of claims 1-4, wherein the proportion of amorphous phase in the fusion glaze layer is >99wt.%.

6. A type of ultra-flat polished ceramic tile, characterized in that, It includes a body layer, a surface glaze layer, and a fused glaze layer as described in claim 5, arranged from bottom to top.

7. The ultra-flat polished ceramic tile according to claim 6, characterized in that, The raw materials for preparing the surface glaze layer include a surface glaze, which comprises the following chemical components by mass fraction: SiO2 55.3%–61.3%, Al2O3 28.5%–33%, CaO 1.0%–1.2%, MgO 0.7%–0.9%, K2O 1.5%–1.9%, Na2O 3.7%–4.7%, with the remainder being loss on ignition and impurities.

8. The ultra-flat polished ceramic tile according to claim 6, characterized in that, An inkjet pattern layer is also provided between the surface glaze layer and the fused glaze layer.

9. A method for preparing ultra-flat polished ceramic tiles, characterized in that, Includes the following steps: S01. Apply a surface glaze to the body layer so that a surface glaze layer is obtained after firing; S02. Apply a fused glaze to obtain a fused glaze layer after firing; S03. Firing and polishing to obtain the ultra-flat polished ceramic tile as described in claim 6 or 7.

10. A method for preparing ultra-flat polished ceramic tiles, characterized in that, Includes the following steps: S01. Apply a surface glaze to the body layer so that a surface glaze layer is obtained after firing; S02. Inkjet print pattern to obtain inkjet pattern layer after firing; S03. Apply a fused glaze to obtain a fused glaze layer after firing; S04. Firing and polishing to obtain the ultra-flat polished ceramic tile as described in claim 8.

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