Preparation method of super-smooth white glaze for daily use porcelain

Abstract

The application discloses a preparation method of super-smooth daily-use porcelain white glaze, which completely replaces traditional quartz as a main silicon source with an industrial by-product lithium residue, introduces bismuth oxide (Bi2O3) as an efficient fluxing agent, and supplements tin oxide (SnO2) and antimony oxide (Sb2O3) as functional additives to form a K-Na-Ca-Mg-Sb-Bi multi-element eutectic system; and introduces potassium nitrate (KNO3) as an oxidation stabilizer to inhibit the precipitation of bismuth-based microcrystals and eliminate the yellowing phenomenon of the glaze surface caused by the change of the valence of bismuth elements, so that high-quality glaze surfaces with super-smooth surfaces and high whiteness are successfully obtained while the firing temperature is significantly reduced. The application significantly reduces the dependence on traditional non-renewable mineral resources such as high-grade quartz and feldspar, saves the raw material cost, meets the needs of green environmental protection and circular economy development, and provides a new path for the sustainable development of the ceramic industry.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of domestic ceramic glaze, and particularly relates to a preparation method of super-smooth domestic porcelain white glaze taking industrial by-product lithium residue as a main silicon source. BACKGROUND

[0002] As a utensil closely related to people's daily life, the glaze of domestic ceramic not only directly affects the aesthetics and use experience of the product, but also relates to food safety and health. The super-smooth and high-whiteness glaze can present a pure and warm texture, improve the visual level and touch comfort of domestic porcelain such as tableware and tea set, and the dense and smooth surface is easier to clean and inhibit bacterial residues. Therefore, to realize the glaze with excellent use performance and elegant aesthetic value is the continuous pursuit in the field of domestic porcelain manufacturing. The final quality of the glaze depends largely on its chemical composition, purity of raw materials and firing process.

[0003] The production of traditional high-quality domestic white glaze relies heavily on high-quality natural mineral raw materials such as high-purity quartz, potassium feldspar and kaolin. This dependence on single and high-grade raw materials not only leads to high production costs, but also results in the continuous consumption of non-renewable resources. On the other hand, in order to achieve the smooth touch and stable high whiteness of the glaze, a large amount of expensive chemical raw materials are often introduced as fluxes (such as lithium carbonate, zinc oxide, etc.) and opacifiers (such as tin oxide, zirconium oxide, etc.), which further increase the production cost of domestic porcelain and limit its popularity in the mass market and competitiveness in the high-end market. How to break the dependence on traditional high-quality raw materials and effectively control the cost under the premise of ensuring the health and safety of the glaze, comfortable touch and visual aesthetics has become a key technical problem faced by the development of domestic ceramic glaze.

[0004] At the same time, the storage and treatment of various industrial solid wastes have become an urgent environmental problem. Among them, lithium residue, as a large amount of solid waste generated in the production process of lithium salt, has a huge emission amount and is currently mainly treated by landfill, which not only occupies land but also has potential environmental risks. However, from the resource perspective, lithium residue usually contains a large amount of SiO2 and Al2O3 components, and its chemical composition has high compatibility with the basic system of ceramic glaze. If it can be applied to ceramic glaze on a large scale and with high added value, the goal of "waste treatment and waste to treasure" will be achieved.

[0005] Bismuth oxide (Bi2O3) as a strong low-temperature flux can reduce the high-temperature surface tension of the glaze, so that the glaze reaches a smooth effect, thereby reducing the surface roughness. However, as a glaze raw material, it will precipitate bismuth-based microcrystals when cooled, showing a cream color, light yellow or straw yellow color. It has little effect on color glaze, but has a greater impact on colorless glaze, which brings great difficulties to the preparation of white glaze. SUMMARY

[0006] The present application aims to overcome the deficiencies of the prior art, and provides a preparation method of super-smooth daily-use porcelain white glaze, which completely replaces traditional quartz with industrial by-product lithium residue as the main silicon source, and introduces bismuth oxide (Bi2O3) as a high-efficiency flux, supplemented with tin oxide (SnO2) and antimony oxide (Sb2O3) as functional additives, to form a K-Na-Ca-Mg-Sb-Bi multi-component eutectic system. Bismuth oxide and antimony oxide serve as main flux materials, which can reduce the glaze melting temperature. Tin oxide serves as an opacifier to enhance whiteness. The three components synergistically work in the glaze to reduce the high-temperature viscosity and surface tension of the glaze, and optimize the melting characteristics and surface spreading properties of the glaze. In particular, potassium nitrate (KNO3) is introduced as a strong oxidizing agent to reduce the yellowing phenomenon of the glaze surface caused by the valence change of bismuth elements, so that through the synergistic effect of the components, a high-quality glaze surface with super-smooth surface and high whiteness is obtained while the firing temperature is significantly reduced.

[0007] The object of the present application is achieved by the following technical solutions:

[0008] The present application provides a preparation method of super-smooth daily-use porcelain white glaze. The raw material composition of the white glaze is as follows: lithium residue 35-40wt%, potassium feldspar 15-20wt%, sodium feldspar 10-15wt%, kaolin 11-18wt%, talc 5-10wt%, calcite 2-4wt%, tin oxide 3-6wt%, bismuth oxide 2-5wt%, and antimony oxide 1-3wt%. The chemical composition of the lithium residue is as follows: SiO272.93-80.94wt%, Al2O38.96-10.92wt%, K2O1.076-1.31wt%, Na2O1.7176-2.34wt%, and IL7.26-12.5wt%. The preparation method comprises the following steps:

[0009] (1) After the raw materials are mixed according to the composition, they are placed in a ball mill for ball milling treatment. After the obtained slurry is aged, a glaze slurry is obtained;

[0010] (2) The glaze slurry is uniformly applied to the surface of the body to obtain a glaze layer. Then, a potassium nitrate solution with a concentration of 0.1-0.3g / ml is uniformly sprayed on the surface of the glaze layer at a spraying amount of 0.025-0.045ml / cm 2 After drying, sintering treatment is carried out at a temperature of 1200-1230℃ for 40-60min, and a super-smooth daily-use porcelain white glaze is obtained.

[0011] Further, in step (1), the ball milling treatment is carried out according to the mass ratio of material: ball: water = 1:2-3:0.5-1.5, the ball milling time is 2-4h, and the aging time is 24-48h.

[0012] Further, the glaze layer thickness in step (2) is 0.1-0.3 mm.

[0013] Further, the super-smooth daily-use porcelain white glaze prepared by the present application has whiteness > 89 and roughness < 0.0087 μm.

[0014] The present application has the following beneficial effects:

[0015] (1) The present application successfully constructs a K-Na-Ca-Mg-Sb-Bi multi-element eutectic system by mixing and ball-milling lithium slag, potassium feldspar, sodium feldspar, calcite, talc and functional additives such as bismuth oxide and antimony oxide. The system can significantly reduce the melting temperature of the glaze, and the glaze can be fired at a relatively low temperature of 1200-1230℃. Ca, Mg, Sb, Bi and Sn effectively reduce the surface tension of the glaze at high temperature, and the flowability and spreading property of the glaze surface are excellent, thereby obtaining a mirror-like super-smooth surface.

[0016] (2) The present application sprays potassium nitrate solution on the surface of the glaze, creates a strong oxidizing atmosphere during firing, and effectively inhibits the yellow tint caused by the change in the valence state of bismuth oxide, thereby ensuring the high whiteness of the final glaze surface. At the same time, by introducing tin oxide as an opacifying agent in the formula, a large number of fine dispersed phases are formed in the glaze melt, which strongly scatter light, and the glaze surface has excellent whiteness.

[0017] (3) The present application uses industrial solid waste lithium slag as the main silicon and aluminum source, and the amount is as high as 30-45% of the total amount of the glaze, which realizes efficient and large-scale consumption of bulk solid waste. This not only significantly reduces the dependence on traditional high-grade quartz, feldspar and other non-renewable mineral resources, saves raw material costs, but also is in line with green and circular economic development, and provides a new path for the sustainable development of the ceramic industry. BRIEF DESCRIPTION OF DRAWINGS

[0018] The present application will be further described in detail below with reference to the embodiments and the accompanying drawings:

[0019] Figure 1 is an atomic force microscope two-dimensional morphology analysis diagram of the glaze surface of the sample obtained in Example Three of the present application;

[0020] Figure 2 is an atomic force microscope three-dimensional morphology analysis diagram of the glaze surface of the sample obtained in Example Three of the present application. DETAILED DESCRIPTION

[0021] The application discloses a preparation method of super-smooth daily-use porcelain white glaze.

[0022] (1) After the raw material components are mixed according to the above-mentioned raw material composition, the mixture is placed in a planetary ball mill, and ball milling treatment is carried out according to the mass ratio of material: ball: water = 1: 2-3: 0.5-1.5, the ball milling time is 2-4h, and the obtained slurry is aged for 24-48h to obtain glaze slurry;

[0023] (2) The glaze slurry is uniformly applied to the surface of the body blank to obtain a glaze layer with a thickness of 0.1-0.3mm; then a potassium nitrate solution with a concentration of 0.1-0.3g / ml is sprayed on the surface of the glaze layer by using a watering can with a spraying amount of 0.025-0.045ml / cm 2 After drying, sintering treatment is carried out at a temperature of 1200-1230℃, and the holding time is 40min, to obtain the super-smooth daily-use porcelain white glaze.

[0024] The raw material composition of the white glaze in each embodiment of the application is shown in Table 1; and the chemical composition of each raw material is shown in Table 2.

[0025] Table 1 Raw material composition (wt%) of the white glaze in each embodiment of the application:

[0026]

[0027] Table 2 Chemical composition (wt%) of the raw material used in the embodiments of the application:

[0028]

[0029] The process parameters of each embodiment of the application are shown in Table 3.

[0030] Table 3 Process parameters of each embodiment of the application:

[0031]

[0032] Comparative Example One:

[0033] Comparative Example One is not added with antimony oxide and does not use a potassium nitrate solution, and the remaining conditions are the same as those in Embodiment One, Embodiment Two, Embodiment Three and Embodiment Four, and four groups of experiments are carried out.

[0034] Comparative Example Two:

[0035] As a comparative example 3, bismuth oxide was not added, and potassium nitrate solution was not used, and the other conditions were the same as in example 1, example 2, example 3, and example 4, and four groups of experiments were carried out.

[0036] Comparative example 3:

[0037] As a comparative example 3, bismuth oxide was not added, and potassium nitrate solution was not used, and the other conditions were the same as in example 1, example 2, example 3, and example 4, and four groups of experiments were carried out.

[0038] The atomic force microscope topography analysis of the sample glaze surface prepared in example 3 is shown in Figure 1 , Figure 2 The results show that the sample glaze surface is smooth. The glaze roughness test was carried out according to the detection method of GB / T 3810.14-2016; the glaze whiteness test was carried out according to the detection method of GB / T 5950-2008. The performance indicators of the glaze obtained in each example and comparative example of the application are shown in table 4.

[0039] Table 4 Performance indicators of the glaze obtained in each example and comparative example of the application:

[0040]

[0041] Note: The performance indicators of each comparative example are the average values of four groups of experiments.

[0042] Analysis of the performance data in table 4: the whiteness of comparative example 1 decreased to 65.8, and the roughness increased to 0.01756 μm; the whiteness of comparative example 2 decreased to 63.3, and the roughness increased to 0.02048 μm; the whiteness of comparative example 3 decreased to 71.1, and the roughness increased to 0.01699 μm. This shows that the strong oxidizing effect of potassium nitrate solution and the synergistic addition of the three oxides significantly improves the whiteness of the glaze and reduces the roughness. The mechanism is that in the K-Na-Ca-Mg-Sb-Bi multi-component eutectic system designed in the application, bismuth oxide as a high-efficiency flux reduces the glaze melting temperature, tin oxide as an opacifier enhances the whiteness, and antimony oxide as an auxiliary flux cooperates with bismuth oxide to reduce the surface tension. The three synergistically optimize the excellent glaze melting fluidity, surface spreading property, and opacification effect.

Claims

1. A method for preparing an ultra-smooth daily-use porcelain white glaze, characterized in that: The raw material composition of the white glaze is as follows: lithium slag 35-40 wt%, potassium feldspar 15-20 wt%, sodium feldspar 10-15 wt%, kaolin 11-18 wt%, talc 5-10 wt%, calcite 2-4 wt%, tin oxide 3-6 wt%, bismuth oxide 2-5 wt%, and antimony oxide 1-3 wt%. The chemical composition of the lithium slag is: SiO2 72.93-80.94 wt%, Al2O 38.96-10.92 wt%, K2O 1.076-1.31 wt%, Na2O 1.7176-2.34 wt%, and IL 7.26-12.5 wt%. The preparation method includes the following steps: (1) After mixing the raw materials according to the above composition, the mixture is placed in a ball mill for ball milling. The resulting slurry is aged to obtain a glaze slurry. (2) The glaze slurry is evenly applied to the surface of the unglazed body to obtain a glaze layer; then a potassium nitrate solution with a concentration of 0.1-0.3 g / ml is sprayed at a rate of 0.025-0.045 ml / cm². 2 The glaze is evenly sprayed onto the surface of the glaze layer, dried, and then sintered at 1200–1230℃ for 40–60 minutes to obtain an ultra-smooth daily-use porcelain white glaze.

2. The method for preparing ultra-smooth daily-use porcelain white glaze according to claim 1, characterized in that: In step (1), ball milling is performed at a mass ratio of material:ball:water = 1:2~3:0.5~1.

5.

3. The method for preparing ultra-smooth daily-use porcelain white glaze according to claim 1, characterized in that: The aging time in step (1) is 24 to 48 hours.

4. The method for preparing ultra-smooth daily-use porcelain white glaze according to claim 1, characterized in that: In step (2), the glaze thickness is 0.1 to 0.3 mm.

5. The method for preparing ultra-smooth daily-use porcelain white glaze according to claim 1, characterized in that: The resulting ultra-smooth daily-use porcelain white glaze has a whiteness > 89 and a roughness < 0.0087 μm.

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