Sanitary ceramic high-gloss black glaze and preparation method thereof

Abstract

The application relates to the technical field of ceramics, in particular to a sanitary ceramic high-gloss black glaze and a preparation method thereof. The sanitary ceramic high-gloss black glaze comprises the following raw materials in parts by mass: 20-24 parts of potash feldspar, 30-36 parts of quartz powder, 3-5 parts of kaolin, 2.5-3.5 parts of aluminum oxide, 7-8 parts of calcined kaolin, 20-24 parts of wollastonite, 2.5-3.5 parts of dolomite, 0.7-0.9 parts of zinc oxide, 2-4 parts of strontium carbonate, 4.5-6 parts of black agent, and the mass ratio of the potash feldspar and the quartz powder is 1:1.5. The sanitary ceramic high-gloss black glaze has the characteristics of excellent gloss, good thermal shock resistance, no defects and strong color feeling, can meet the demand of users for high-quality sanitary ceramic products, and has wide market space and artistic value.

Description

Technical Field

[0001] This application relates to the field of ceramic technology, and in particular to a high-gloss black glaze for sanitary ceramics and its preparation method. Background Technology

[0002] Currently, my country's sanitary ceramics products suffer from problems such as limited variety, incomplete designs, and low quality. Research on high-end sanitary ceramics with colored glazes lays the foundation for improving product quality and increasing design variety. Bathroom fixtures are predominantly white, failing to meet the diverse market and personalized demands. Black is a relatively precious color in sanitary ceramic glazes, belonging to the dark color family; when properly combined, black products can exude elegance and luxury.

[0003] Black-glazed ceramics, with their dignified, elegant, noble, and stable glaze characteristics, have been beloved for centuries. Throughout history, the research and improvement of black glaze have been continuous. Traditional black glaze techniques suffer from unstable color, and the glaze surface is prone to defects such as pinholes, glaze shrinkage, and low gloss. The firing process is also difficult to master, resulting in a low product qualification rate and high production costs. Currently, a hot research topic is how to simplify the process, appropriately reduce production costs, and meet the requirements of green and environmentally friendly production, while ensuring high blackness, high gloss, pure color, and stable performance of the black glaze. Summary of the Invention

[0004] The purpose of this application is to address the shortcomings of current technology by providing a high-gloss black glaze for sanitary ceramics and its preparation method.

[0005] In the first aspect, this application provides a high-gloss black glaze for sanitary ceramics, as follows:

[0006] A high-gloss black glaze for sanitary ceramics comprises the following raw materials in parts by weight: 20-24 parts potassium feldspar, 30-36 parts quartz powder, 3-5 parts kaolin, 2.5-3.5 parts alumina, 7-8 parts calcined kaolin, 20-24 parts wollastonite, 2.5-3.5 parts dolomite, 0.7-0.9 parts zinc oxide, 2-4 parts strontium carbonate, and 4.5-6 parts blackening agent, wherein the mass ratio of potassium feldspar to quartz powder is 1:1.5.

[0007] By employing the above technical solutions, potassium feldspar provides the main glass-forming oxide—K₂O—in the glaze melt, increasing its surface tension and reducing high-temperature viscosity, thereby reducing pinhole formation and resulting in a brighter and smoother glaze surface. Quartz powder provides the silicon source in the glaze, namely SiO₂. The presence of quartz powder can increase the glaze's initial melting temperature, viscosity, and mechanical strength, while reducing its smoothness coefficient. By controlling the mass ratio of potassium feldspar to quartz powder to 1:1.5, their synergistic effect can be utilized to obtain a black glaze with high gloss. Kaolin mainly provides Al₂O₃, increasing the glaze's viscosity and hardness, and improving its resistance to chemical erosion. Alumina further increases the glaze's viscosity and hardness, contributing to improved mechanical strength and resistance. Calcined kaolin improves the glaze's quality, enhancing its gloss and smoothness. Wollastonite powder provides CaO; a small amount of wollastonite is added to the formula to replace some of the calcite. Wollastonite has little or no loss on ignition, and the CaO it provides has a strong fluxing effect, which not only helps reduce or eliminate bubbles in the glaze layer, but also relatively reduces undissolved quartz grains in the glaze layer, thus improving the wear resistance and gloss of the glaze. Dolomite: also provides CaO and MgO in the glaze, increasing its gloss and resistance to chemical erosion. Zinc oxide: adjusts the color of the glaze and also helps improve its thermal shock resistance. Strontium carbonate: also adjusts the color of the glaze and helps increase its gloss. Blackening agent: adjusts the color of the glaze, giving it a high degree of blackness. Through the proportions and synergistic effects of the above components, the high-gloss black glaze for sanitary ceramics prepared in this application has high blackness, a glaze gloss ≥96GU, thermal shock resistance: no cracking after three rapid cooling cycles from 200℃ to 20℃, no pinholes, glaze shrinkage, or glaze flow, strong color, and good overall artistic effect, thus possessing broad market potential.

[0008] Preferably, the blackening agent is one or more of cobalt black material, iron black material, and manganese oxide.

[0009] Preferably, the blackening agent is a composition of cobalt black material, iron black material and manganese oxide in a mass ratio of 1:5-8:0.5.

[0010] By adopting the above technical solution, the black agent in this application can be one or more of cobalt black pigment, iron black pigment, and manganese oxide. Preferably, the black agent is a composition with a mass ratio of 1:5 to 8:0.5. The function of the black agent is to adjust the color of the glaze to achieve a high degree of blackness. Cobalt black pigment, iron black pigment, and manganese oxide are all commonly used black pigments. They can absorb most of the light to form a deep black color effect. Cobalt black pigment is mainly composed of cobalt(II) oxide and has a good black coloring effect. It is often used in ceramic glazes. Iron black pigment is mainly composed of iron(III) oxide and can provide a deep black. Manganese oxide is another commonly used black pigment that can produce a deep brownish-black color effect. The synergistic effect of these black agents can be adjusted by the mass ratio of the composition. In the composition, cobalt black pigment, iron black pigment, and manganese oxide are combined in a mass ratio of 1:5 to 8:0.5. Such a ratio allows the characteristics of each black agent to complement each other, achieving a more ideal black effect. At the same time, this ratio can also ensure the dispersion and stability of the black agent in the glaze, guaranteeing a strong color on the final glaze surface.

[0011] Secondly, this application provides a method for preparing a high-gloss black glaze for sanitary ceramics, as follows:

[0012] A method for preparing a high-gloss black glaze for sanitary ceramics, using the aforementioned raw materials for a high-gloss black glaze for sanitary ceramics, includes the following steps:

[0013] S1 Pulping: According to the mass fraction, potassium feldspar, quartz powder, kaolin, alumina, calcined kaolin, wollastonite, dolomite, zinc oxide, strontium carbonate and blackening agent are loaded into a ball mill, and an appropriate amount of water is added for wet grinding. After ball milling, the slurry is discharged from the mill, sieved, and iron is removed to prepare black glaze slurry for later use.

[0014] S2 spray glazing: The obtained black glaze slurry is sprayed onto the surface of a clean sanitary ceramic green body, resulting in a glazed sanitary ceramic green body with a glaze layer thickness of 0.7-0.9mm;

[0015] S3 Drying: Drying the glazed sanitary ceramic body;

[0016] S4 Firing: The dried sanitary ceramic blanks are loaded into a sanitary ceramic kiln for sintering. The firing process is as follows: the temperature is increased from room temperature to 400-450℃ at a rate of 2-3℃ / min and held for 30min, then increased to 900-950℃ at a rate of 4-5℃ / min and held for 30-50min, and finally increased to 1220-1240℃ at a rate of 2-3℃ / min and held for 10-20min. Finally, heating is stopped and the ceramic blanks are allowed to cool naturally to room temperature to obtain black glazed sanitary ceramic products.

[0017] By adopting the above technical solutions, S1 Slurry Preparation: Various raw materials are mixed evenly through wet grinding in a ball mill to form a black glaze slurry. Wet grinding can accelerate the mixing and refinement of raw materials, which is beneficial to the uniform distribution of components and the stability of the glaze. The sieving and iron removal processes can remove impurities and improve the purity of the glaze. S2 Glazing: Glazing involves evenly spraying the black glaze slurry onto the surface of the sanitary ceramic green body to form a glaze layer. The purpose of glazing is to evenly cover the surface of the body with glaze to achieve uniformity and consistency, so that the final product has a uniform appearance and color. When the glaze thickness is less than 0.7mm, small defects appear on the glaze surface, and the glaze color is uneven (the glaze color is not full), resulting in poor color development (black). Conversely, when the glaze thickness is too thick, it increases the cost of glazing and glaze slurry, and the glaze surface is prone to cracking after glazing, and glaze shrinkage occurs after firing. S3 Drying: The glazed sanitary ceramic green body is dried to remove moisture from the glaze. During the drying process, the moisture in the body gradually evaporates, forming a strong bond between the glaze and the body to maintain the smoothness and integrity of the glaze. S4 Firing: The dried sanitary ceramic body is placed in a kiln for sintering. During firing, the control of the heating rate and holding time has a significant impact on the melting and fluidity of the glaze. Appropriate heating rates and holding times allow the glaze to fully melt and form a smooth and delicate surface, while avoiding defects and deformation. After firing within the temperature range (1220-1240℃), the glaze produces sufficient liquid phase, resulting in a smooth, delicate surface with high gloss. Firing at excessively high temperatures (above 1240℃) can cause the glaze to boil, resulting in small, sandwich-like bubbles; firing at excessively low temperatures (below 1220℃) can lead to underfiring, significantly reducing the gloss of the glaze. In summary, each step in the above preparation method serves the functions of mixing, spraying, drying, and sintering in this application, with the key being to achieve uniform application of black glaze, bonding of glaze with the body, and a smooth and even glaze surface with good color effect.

[0018] Preferably, in step S1, the total mass of potassium feldspar, quartz powder, kaolin, alumina, calcined kaolin, wollastonite, dolomite, zinc oxide, strontium carbonate, and blackening agent is M, the mass ratio of M:ball:water during ball milling is 2:4.5-5:1.4-1.7, and the ball milling time is 8-12 hours.

[0019] Preferably, in step S1 pulping, the sieving is performed through a 325-mesh standard sieve, and the residue after passing through the 325-mesh standard sieve is less than 0.1%.

[0020] Preferably, in step S1 of pulp preparation, the proportion of particles smaller than 10μm in the black glaze slurry is 65-75%.

[0021] By adopting the above technical solutions, the finer the particles in the glaze slurry, the better the suspension, and the lower the melting temperature of the glaze, resulting in a higher gloss of the glaze surface after firing. Particle size also affects the surface tension, high-temperature viscosity, surface roughness, and gloss of the glaze surface. When the fineness (10μm) is less than 65%, the particles are too coarse and do not easily form a liquid phase, thus increasing the viscosity and failing to form a smooth and even glaze surface. When the fineness (10μm) is greater than 75%, the particles are too small, causing chicken-foot-like cracks on the surface of the glaze blank after spraying, and easily leading to glaze shrinkage defects after firing.

[0022] Preferably, in step S1, the performance parameters of the black glaze slurry are: specific gravity of 1.745 kg / L-1.755 kg / L and fluidity of 100 mL glaze slurry with a flow time of 120-140 seconds.

[0023] Preferably, in step S3, the drying temperature is 110-120°C and the drying time is 30-60 minutes.

[0024] Preferably, the gloss of the glaze of the sanitary ceramic black glaze product is ≥96GU, and its thermal shock resistance is: it will not crack after being rapidly cooled three times from 200℃ to 20℃.

[0025] In summary, the beneficial technical effects of this application are as follows:

[0026] 1. High gloss: Through scientific raw material formulation and preparation process, the firing temperature is controlled within the range of 1220-1240℃, which allows the glaze to generate sufficient liquid phase during the firing process, thus making the glaze surface appear smooth and delicate, and with high gloss.

[0027] 2. Excellent thermal shock resistance: The high-gloss black glaze of the sanitary ceramics, after firing, can withstand three rapid cooling cycles from 200℃ to 20℃ without cracking. This indicates a strong bond between the glaze and the ceramic body, demonstrating good thermal shock resistance.

[0028] 3. Defect-free glaze: The black glaze products, after spraying and firing, exhibit a surface free of pinholes, glaze shrinkage, and glaze runs. This indicates that the glaze has good fluidity during spraying and firing, and can maintain good surface quality while being applied evenly.

[0029] 4. Strong Color Sense: Through scientific black agent formulation design, the glaze exhibits a high degree of blackness and a strong color sense, giving the high-gloss black glaze of sanitary ceramics a good visual effect that meets market demand. Detailed Implementation

[0030] The embodiments of this application will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of this application. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0031] Example 1

[0032] A high-gloss black glaze for sanitary ceramics comprises the following raw materials in parts by weight: 20 parts potassium feldspar, 30 parts quartz powder, 3 parts kaolin, 2.5 parts alumina, 7 parts calcined kaolin, 20 parts wollastonite, 2.5 parts dolomite, 0.7 parts zinc oxide, 2 parts strontium carbonate, and 4.5 parts cobalt black pigment.

[0033] A method for preparing a high-gloss black glaze for sanitary ceramics, using the aforementioned raw materials for a high-gloss black glaze for sanitary ceramics, includes the following steps:

[0034] S1 Pulping: Potassium feldspar, quartz powder, kaolin, alumina, calcined kaolin, wollastonite, dolomite, zinc oxide, strontium carbonate, and cobalt black material are loaded into a ball mill according to mass proportions. An appropriate amount of water is added for wet milling. Let the total mass of potassium feldspar, quartz powder, kaolin, alumina, calcined kaolin, wollastonite, dolomite, zinc oxide, strontium carbonate, and cobalt black material be M. The mass ratio of M:ball:water during ball milling is 2:4.5:1.4. The ball milling time is 8 hours. After ball milling, the slurry is discharged from the mill and passed through a 325-mesh standard sieve. The residue after passing through the 325-mesh standard sieve is 0.05%. Iron is removed, and a black glaze slurry is prepared for later use. The black glaze slurry contains 65% particles smaller than 10μm. The performance parameters of the black glaze slurry are: specific gravity 1.745 kg / L, and flowability 100 mL glaze slurry flow time 120 seconds.

[0035] S2 spray glazing: The obtained black glaze slurry is sprayed onto the clean surface of the sanitary ceramic green body, resulting in a glazed sanitary ceramic green body with a glaze layer thickness of 0.7mm;

[0036] S3 Drying: Dry the glazed sanitary ceramic body at a temperature of 110℃ for 60 minutes.

[0037] S4 Firing: The dried sanitary ceramic blanks are loaded into a sanitary ceramic kiln for sintering. The firing process is as follows: the temperature is increased from room temperature to 400℃ at a rate of 2℃ / min and held for 30min, then increased to 900℃ at a rate of 4℃ / min and held for 50min, and finally increased to 1220℃ at a rate of 2℃ / min and held for 20min. Finally, the heating is stopped and the ceramic is allowed to cool naturally to room temperature to obtain black glazed sanitary ceramic products.

[0038] Example 2

[0039] A high-gloss black glaze for sanitary ceramics comprises the following raw materials in parts by weight: 24 parts potassium feldspar, 36 parts quartz powder, 5 parts kaolin, 3.5 parts alumina, 8 parts calcined kaolin, 24 parts wollastonite, 3.5 parts dolomite, 0.9 parts zinc oxide, 4 parts strontium carbonate, and 6 parts iron black pigment.

[0040] A method for preparing a high-gloss black glaze for sanitary ceramics, using the aforementioned raw materials for a high-gloss black glaze for sanitary ceramics, includes the following steps:

[0041] S1 Pulping: Potassium feldspar, quartz powder, kaolin, alumina, calcined kaolin, wollastonite, dolomite, zinc oxide, strontium carbonate, and iron ferrous oxide are loaded into a ball mill according to mass proportions. An appropriate amount of water is added for wet milling. Let the total mass of potassium feldspar, quartz powder, kaolin, alumina, calcined kaolin, wollastonite, dolomite, zinc oxide, strontium carbonate, and iron ferrous oxide be M. The mass ratio of M:ball:water during ball milling is 2:5:1.7. The ball milling time is 12 hours. After ball milling, the slurry is discharged from the mill and passed through a 325-mesh standard sieve. The residue after passing through the 325-mesh standard sieve is 0.08%, removing iron, and a black glaze slurry is prepared for later use. The black glaze slurry contains 75% particles smaller than 10μm. The performance parameters of the black glaze slurry are: specific gravity 1.755 kg / L, and flowability 100 mL glaze slurry flow time 140 seconds.

[0042] S2 spray glazing: The obtained black glaze slurry is sprayed onto the clean surface of the sanitary ceramic green body, resulting in a glazed sanitary ceramic green body with a glaze layer thickness of 0.9mm;

[0043] S3 Drying: Dry the glazed sanitary ceramic body at a temperature of 120℃ for 30 minutes.

[0044] S4 Firing: The dried sanitary ceramic blanks are loaded into a sanitary ceramic kiln for sintering. The firing process is as follows: the temperature is increased from room temperature to 450℃ at a rate of 3℃ / min and held for 30min, then increased to 950℃ at a rate of 5℃ / min and held for 30min, and finally increased to 1240℃ at a rate of 3℃ / min and held for 10min. Finally, the heating is stopped and the ceramic is allowed to cool naturally to room temperature to obtain black glazed sanitary ceramic products.

[0045] Example 3

[0046] A high-gloss black glaze for sanitary ceramics comprises the following raw materials in parts by weight: 22 parts potassium feldspar, 33 parts quartz powder, 4 parts kaolin, 3 parts alumina, 7.5 parts calcined kaolin, 22 parts wollastonite, 3 parts dolomite, 0.8 parts zinc oxide, 3 parts strontium carbonate, and 5 parts manganese oxide.

[0047] A method for preparing a high-gloss black glaze for sanitary ceramics, using the aforementioned raw materials for a high-gloss black glaze for sanitary ceramics, includes the following steps:

[0048] S1 Pulping: Potassium feldspar, quartz powder, kaolin, alumina, calcined kaolin, wollastonite, dolomite, zinc oxide, strontium carbonate, and manganese oxide are loaded into a ball mill according to mass proportions. An appropriate amount of water is added for wet milling. Let the total mass of potassium feldspar, quartz powder, kaolin, alumina, calcined kaolin, wollastonite, dolomite, zinc oxide, strontium carbonate, and manganese oxide be M. The mass ratio of M:ball:water during ball milling is 2:4.8:1.6. The ball milling time is 9 hours. After ball milling, the slurry is discharged from the mill and passed through a 325-mesh standard sieve. The residue after passing through the 325-mesh standard sieve is 0.02%. Iron is removed, and a black glaze slurry is prepared for later use. The black glaze slurry contains 70% particles smaller than 10μm. The performance parameters of the black glaze slurry are: specific gravity 1.750 kg / L, and flowability 100 mL glaze slurry flow time 130 seconds.

[0049] S2 spray glazing: The obtained black glaze slurry is sprayed onto the clean surface of the sanitary ceramic green body, resulting in a glazed sanitary ceramic green body with a glaze layer thickness of 0.8mm;

[0050] S3 Drying: Dry the glazed sanitary ceramic body at a temperature of 115℃ for 40 minutes.

[0051] S4 Firing: The dried sanitary ceramic blanks are loaded into a sanitary ceramic kiln for sintering. The firing process is as follows: the temperature is increased from room temperature to 430℃ at a rate of 2.5℃ / min and held for 30 minutes, then increased to 930℃ at a rate of 4.5℃ / min and held for 40 minutes, and finally increased to 1230℃ at a rate of 2.5℃ / min and held for 15 minutes. Finally, the heating is stopped and the ceramic is allowed to cool naturally to room temperature to obtain black glazed sanitary ceramic products.

[0052] Example 4

[0053] Similar to Example 3, except that an equal amount of cobalt black pigment, iron black pigment and manganese oxide in a mass ratio of 1:5:0.5 are used instead of manganese oxide.

[0054] Example 5

[0055] Similar to Example 3, except that an equal amount of cobalt black pigment, iron black pigment and manganese oxide in a mass ratio of 1:8:0.5 are used instead of manganese oxide.

[0056] Example 6

[0057] Similar to Example 3, except that an equal amount of cobalt black pigment, iron black pigment and manganese oxide in a mass ratio of 1:7:0.5 are used instead of manganese oxide.

[0058] Comparative Example 1

[0059] Similar to Example 6, except that 18 parts of potassium feldspar and 37 parts of quartz powder were used instead of 22 parts of potassium feldspar and 33 parts of quartz powder.

[0060] Comparative Example 2

[0061] Similar to Example 6, except that 26 parts of potassium feldspar and 29 parts of quartz powder were used instead of 22 parts of potassium feldspar and 33 parts of quartz powder.

[0062] Comparative Example 3

[0063] Similar to Example 6, except that the proportion of particles smaller than 10 μm in the black glaze paste is 60%.

[0064] Comparative Example 4

[0065] Similar to Example 6, except that the proportion of particles smaller than 10μm in the black glaze paste is 80%.

[0066] Comparative Example 5

[0067] Similar to Example 6, except that in step S4 firing: the temperature is finally raised to 1200°C at a rate of 2.5°C / min and held for 15min.

[0068] Comparative Example 6

[0069] Similar to Example 6, except that in step S4 firing: the temperature is finally raised to 1260°C at a rate of 2.5°C / min and held for 15min.

[0070] Performance testing

[0071] Samples of the sanitary ceramic black glaze products prepared in Examples 1-6 and Comparative Examples 1-6 were taken and tested. The test results are shown in Table 1.

[0072] Gloss determination: The gloss of the sample is tested using a WGG-60 gloss meter. Simply align the measuring port of the gloss meter with the sample to be measured, press the button, and the measurement will start automatically. The value displayed on the screen after the measurement is completed is the gloss result of the sample.

[0073] Determination of stain resistance: Wipe the surface of the product or test piece clean with a soft cloth, and then test it at 100cm. 2Add 3-4 drops of ink to the surface, then use your right hand, wearing a rubber glove, to clench your fingers and spread the ink evenly and grind it repeatedly. After 3 minutes, rinse the ink off the surface with water and observe the amount of black stains adsorbed on the glaze surface. The glaze is divided into 1-5 grades, with higher grades indicating stronger stain resistance.

[0074] Determination of thermal stability: Place the product or test piece in an electric heating constant temperature drying oven and bake at 200℃ for 3 hours. Then place it in cold water at 20℃. After the product or test piece temperature drops to 20℃, place it in a container filled with red ink solution and immerse it for 10 minutes (the red ink solution should submerge the test object). Take it out and observe whether there are cracks on the glaze surface.

[0075] Color difference determination: The color difference was tested using an X-Rite Ci60 colorimeter from the USA. This colorimeter is a portable digital display. During measurement, after selecting the standard to be used, simply align the measuring port of the colorimeter with the sample to be measured, press the button, and the measurement will start automatically. The value displayed on the screen after the measurement is completed is the color difference result of the sample.

[0076] Table 1

[0077]

[0078] As shown in Table 1, the sanitary ceramic black glaze products prepared in Examples 1-6 have a gloss greater than 96 GU, a stain resistance of the highest level 5, and thermal shock resistance: they do not crack after three rapid cooling cycles from 200℃ to 20℃. Their color difference L-value is between 22.68 and 27.23, indicating a very deep black color. A comparative analysis of the color difference L-values ​​of the sanitary ceramic black glaze products prepared in Examples 1-3 and Examples 4-6 shows that the sanitary ceramic black glaze products prepared using a composition of cobalt black material, iron black material, and manganese oxide in a mass ratio of 1:5-8:0.5 have a deeper black color and a higher gloss.

[0079] As shown in Table 1, the performance comparison analysis of the sanitary ceramic black glaze products prepared in Example 6 and Comparative Examples 1-2 shows that by controlling the mass ratio of potassium feldspar and quartz powder to 1:1.5, and utilizing their synergistic effect, a black glaze with high gloss can be obtained, and the overall performance of the sanitary ceramic black glaze products is superior.

[0080] As shown in Table 1, a comparative analysis of the performance of the sanitary ceramic black glaze products prepared in Example 6 and Comparative Examples 3-4 reveals that the finer the particles in the glaze slurry, the better the suspension, and the lower the melting temperature of the glaze, resulting in a higher gloss after firing. Particle size also affects the surface tension, high-temperature viscosity, surface roughness, and gloss of the glaze. When the fineness (10μm) is less than 65%, the particles are too coarse and do not easily form a liquid phase, thus increasing the viscosity and preventing the formation of a smooth and even glaze surface. When the fineness (10μm) is greater than 75%, the particles are too small, leading to chicken-foot-like cracks on the surface of the glaze blank after spraying, and easily causing glaze shrinkage defects after firing.

[0081] As shown in Table 1, the performance comparison of the sanitary ceramic black glaze products prepared in Example 6 and Comparative Examples 5-6 reveals that the control of heating rate and holding time during firing has a significant impact on the melting and fluidity of the glaze. Appropriate heating rate and holding time allow the glaze to fully melt and form a smooth and delicate surface, while avoiding defects and deformation. After firing within the temperature range (1220-1240℃), the glaze produces sufficient liquid phase, resulting in a smooth, delicate surface with high gloss. Excessively high firing temperatures (above 1240℃) cause the glaze to boil, resulting in small bubbles resembling sandwich glazes; excessively low firing temperatures (below 1220℃) lead to underfiring, significantly reducing the gloss of the glaze.

[0082] The above embodiments are only used to explain the technical solutions of this application and are not intended to limit it. Although the above embodiments have provided specific descriptions of this application, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation methods of this application. Any modifications and equivalent substitutions that do not depart from the spirit and scope of this application should be covered within the protection scope of this application.

Claims

1. A high-gloss black glaze for sanitary ceramics, characterized in that, The raw materials include the following parts by weight: 20-24 parts potassium feldspar, 30-36 parts quartz powder, 3-5 parts kaolin, 2.5-3.5 parts alumina, 7-8 parts calcined kaolin, 20-24 parts wollastonite, 2.5-3.5 parts dolomite, 0.7-0.9 parts zinc oxide, 2-4 parts strontium carbonate, and 4.5-6 parts blackening agent. The mass ratio of potassium feldspar to quartz powder is 1:1.

5.

2. The high-gloss black glaze sanitary ceramic according to claim 1, characterized in that, The blackening agent is one or more of cobalt black material, iron black material, and manganese oxide.

3. The high-gloss black glaze sanitary ceramic according to claim 2, characterized in that, The blackening agent is a composition of cobalt black material, iron black material and manganese oxide in a mass ratio of 1:5-8:0.

5.

4. A method for preparing a high-gloss black glaze for sanitary ceramics, characterized in that, The preparation method of the high-gloss black glaze for sanitary ceramics using the raw materials described in any one of claims 1-3 includes the following steps: S1 Slurry Preparation: According to the mass fraction, potassium feldspar, quartz powder, kaolin, alumina, calcined kaolin, wollastonite, dolomite, zinc oxide, strontium carbonate, and blackening agent are loaded into a ball mill, and an appropriate amount of water is added for ball milling. After ball milling, the slurry is discharged from the mill, sieved, and iron is removed to prepare a black glaze slurry for later use; S2 Glazing: The obtained black glaze slurry is sprayed onto the surface of a clean sanitary ceramic green body to obtain a glazed sanitary ceramic green body with a glaze layer thickness of 0.7-0.9mm; S3 Drying: Drying the glazed sanitary ceramic body; S4 Firing: The dried sanitary ceramic blanks are loaded into a sanitary ceramic kiln for sintering. The firing process is as follows: the temperature is increased from room temperature to 400-450℃ at a rate of 2-3℃ / min and held for 30min, then increased to 900-950℃ at a rate of 4-5℃ / min and held for 30-50min, and finally increased to 1220-1240℃ at a rate of 2-3℃ / min and held for 10-20min. Finally, the heating is stopped and the ceramic blanks are allowed to cool naturally to room temperature to obtain black glazed sanitary ceramic products. In step S1, during the pulping process, the proportion of particles smaller than 10μm in the black glaze slurry is 65-75%.

5. The method for preparing a high-gloss black glaze for sanitary ceramics according to claim 4, characterized in that, In step S1, the total mass of potassium feldspar, quartz powder, kaolin, alumina, calcined kaolin, wollastonite, dolomite, zinc oxide, strontium carbonate, and blackening agent is M. The mass ratio of M:ball:water during ball milling is 2:4.5-5:1.4-1.7, and the ball milling time is 8-12 hours.

6. The method for preparing a high-gloss black glaze for sanitary ceramics according to claim 4, characterized in that, In step S1 pulping, the sieving is done through a 325-mesh standard sieve, and the residue after passing through the 325-mesh standard sieve is less than 0.1%.

7. The method for preparing a high-gloss black glaze for sanitary ceramics according to claim 4, characterized in that, In step S1, the performance parameters of the black glaze slurry are: specific gravity of 1.745 kg / L-1.755 kg / L, and flowability of 100 mL of glaze slurry with a flow time of 120-140 seconds.

8. The method for preparing a high-gloss black glaze for sanitary ceramics according to claim 4, characterized in that, In step S3, the drying temperature is 110-120℃ and the drying time is 30-60 min.

9. The method for preparing a high-gloss black glaze for sanitary ceramics according to claim 4, characterized in that, The gloss of the black glaze sanitary ceramic product is ≥96GU, and its thermal shock resistance is: it will not crack after being rapidly cooled three times from 200℃ to 20℃.

Images