阅读说明：本技术 高耐磨防污微晶装饰陶瓷厚板及其制备方法 (High-wear-resistance antifouling microcrystal decorative ceramic thick plate and preparation method thereof ) 是由 谢志军 欧阳成 黄玲艳 卢海鹏 黄秋立 肖伟荣 于 2019-12-02 设计创作，主要内容包括：本发明公开高耐磨防污微晶装饰陶瓷厚板及其制备方法。高耐磨防污微晶装饰陶瓷厚板的制备方法,包括以下步骤：使用坯体粉料制备高强通体陶瓷厚板坯体,所述坯体强度为2.8～3.5MPa；在坯体上布施面釉,所述面釉施釉量为520～580g/m<Sup>2</Sup>；布施高耐磨干粒柔光釉,所述高耐磨干粒柔光釉施釉量为250～300g/m<Sup>2</Sup>；在1200～1290℃温度下烧成75～180min；制得大规格陶瓷厚板。(The invention discloses a high-wear-resistance antifouling microcrystal decorative ceramic thick plate and a preparation method thereof. The preparation method of the high wear-resistant antifouling microcrystal decorative ceramic thick plate comprises the following steps: preparing a high-strength through-body ceramic thick plate blank by using blank powder, wherein the strength of the blank is 2.8-3.5 MPa; spreading overglaze on the blank body, wherein the overglaze application amount is 520-580g/m 2 (ii) a Applying the high-wear-resistance dry-particle soft glaze, wherein the glazing amount of the high-wear-resistance dry-particle soft glaze is 250-300 g/m 2 (ii) a Firing at 1200-1290 ℃ for 75-180 min; and manufacturing the large-size ceramic thick plate.)

1. The preparation method of the high wear-resistant antifouling microcrystal decorative ceramic thick plate is characterized by comprising the following steps:

preparing a high-strength through-body ceramic thick plate blank by using blank powder, wherein the strength of the blank is 2.8-3.5 MPa;

spreading overglaze on the blank body, wherein the overglaze application amount is 520-580g/m²；

Applying the high-wear-resistance dry-particle soft glaze, wherein the glazing amount of the high-wear-resistance dry-particle soft glaze is 250-300 g/m²；

Firing at 1200-1290 ℃ for 75-180 min;

preparing a large-size ceramic thick plate; the ceramic thick plate has the following specifications: 760 to 1600mm wide, 1800 to 3600mm long and 5.5 to 20.5mm thick.

2. The preparation method according to claim 1, wherein the chemical composition of the green body powder comprises: by mass percentage, the loss on ignition is 4.8-5.0%, and SiO is₂ 57.5-58.5%，Al₂O₃ 27.8-28.5%，Fe₂O₃ 0.75-0.80%，TiO₂ 0.58-0.62%，CaO 0.35-0.40%，MgO 1.1-1.2%，K₂O 2.2-2.4%，Na₂O 2.5-2.7%。

3. The method according to claim 1, characterized in that the grain composition of the green body powder comprises: 8-18% above 30 meshes, 30-60 meshes: 70-80%, 60-80 mesh: 6-15% and less than 6% below 80 meshes.

4. The method according to claim 1, wherein the overglaze comprises the following chemical components: by mass percentage, loss on ignition is 4-5%, and SiO is₂ 50.7～51.5%，Al₂O₃ 29～30.5%，Fe₂O₃ 0.2～0.3%，CaO 0.35～0.5%，MgO 0.1～0.2%，K₂O 5.5～6.5%，Na₂O 2.0～2.5%，ZrO₂ 5.9～6.5%。

5. The preparation method according to claim 1, wherein the high-wear-resistance dry-grain soft glaze comprises high-wear-resistance dry grains and matte crystalline glaze, and the mass ratio of the matte crystalline glaze to the high-wear-resistance dry grains is 70: 20-70: 30.

6. the preparation method according to claim 5, wherein the chemical composition of the matte crystalline glaze comprises: by mass percentage, the loss on ignition is 7.0-7.2%, and SiO is₂ 48.5～50.0%，Al₂O₃ 19.5～20.5%，Fe₂O₃ 0.15～0.18%，TiO₂ 0.08～1.0%，CaO 9.0～9.5%，MgO1.4～1.6%，K₂O 1.7～1.9%，Na₂O 3.9～4.1%，ZnO 4.8～5.2%。

7. The preparation method according to claim 5, wherein the chemical composition of the high wear-resistant dry particles comprises: by mass percentage, 0.35-0.4% of loss on ignition and Na₂O 3.2～3.4%，SiO₂ 53.5～54.5%，Al₂O₃ 18.6～19.2%，CaO 14.8～15.3%，ZnO 4.0～5.0%，K₂O 2.0～2.5%，SrO 0.5～0.8%，MgO 0.30～0.45%，BaO 0.15～0.20%。

8. The preparation method according to claim 5, wherein the grain composition of the high wear-resistant dry particles is as follows: 0% above 100 mesh, 88-92% below 100-250 mesh, and 8-12% below 250 mesh.

9. The method according to claim 1, wherein the green powder has an alumina content of 28.5 to 29.5 wt%.

10. The high wear-resistant antifouling microcrystal decorative ceramic thick plate obtained by the preparation method of the high wear-resistant antifouling microcrystal decorative ceramic thick plate according to any one of claims 1-9.

Technical Field

The invention relates to a high-wear-resistance antifouling microcrystal decorative ceramic thick plate and a preparation method thereof, belonging to the technical field of ceramic tile production and manufacturing.

Background

With the increase of the specifications of ceramic products, when the strength of a blank is low, the blank is easy to break in the processes of forming, conveying and the like. The invention aims to develop a novel thick ceramic plate which is different from the traditional large plate, can be drilled and polished, is more convenient to cut, is suitable for being made into various shapes, is positioned in high-end household application products, and can be flexibly applied in different occasions. The thick plate has excellent physical and chemical properties and surface decoration effect, and also needs to have good body feeling and good cutting processability.

Disclosure of Invention

Aiming at the problems, the invention provides a high-wear-resistance antifouling microcrystal decorative ceramic thick plate and a preparation method thereof.

In a first aspect, the invention provides a preparation method of a high wear-resistant antifouling microcrystal decorative ceramic thick plate, which comprises the following steps:

preparing a high-strength through-body ceramic thick plate blank by using blank powder, wherein the strength of the blank is 2.8-3.5 MPa;

spreading overglaze on the blank body, wherein the overglaze application amount is 520-580g/m²；

Applying the high-wear-resistance dry-particle soft glaze, wherein the glazing amount of the high-wear-resistance dry-particle soft glaze is 250-300 g/m²；

Firing at 1200-1290 ℃ for 75-180 min;

preparing a large-size ceramic thick plate; the ceramic thick plate has the following specifications: 760 to 1600mm wide, 1800 to 3600mm long and 5.5 to 20.5mm thick.

As the size of ceramic products increases, higher demands are made on the strength of the product blank in order to avoid breakage during the entire production process of the product. When the strength of the green body is low, breakage is easily caused in the forming, conveying and the like processes. Because the ceramic plate has larger specification, the strength of the blank body is attenuated along with the increase of the glazing amount. The damage can be reduced by controlling the glazing amount of the overglaze and the dry particle soft glaze; however, the color development of the product is influenced by the too small glazing amount. The damage rate can be controlled within 2 percent by controlling the strength of the blank body before the high-wear-resistant antifouling ceramic rock plate enters the kiln.

Preferably, the chemical composition of the green body powder comprises: by mass percentage, the loss on ignition is 4.8-5.0%, and SiO is₂57.5-58.5%，Al₂O₃ 27.8-28.5%，Fe₂O₃ 0.75-0.80%，TiO₂ 0.58-0.62%，CaO 0.35-0.40%，MgO 1.1-1.2%，K₂O 2.2-2.4%，Na₂O 2.5-2.7%。

Preferably, the grain composition of the green body powder comprises: 8-18% above 30 meshes, 30-60 meshes: 70-80%, 60-80 mesh: 6-15% and less than 6% below 80 meshes.

Preferably, the content of aluminum oxide in the overglaze is 29.5-30.5%.

Preferably, the chemical composition of the overglaze comprises: by mass percentage, loss on ignition is 4-5%, and SiO is₂ 50.7～51.5%，Al₂O₃ 29～30.5%，Fe₂O₃ 0.2～0.3%，CaO 0.35～0.5%，MgO 0.1～0.2%，K₂O 5.5～6.5%，Na₂O 2.0～2.5%，ZrO₂ 5.9～6.5%。

Preferably, the high-wear-resistance dry particle soft glaze comprises high-wear-resistance dry particles and matte crystalline glaze, wherein the mass ratio of the matte crystalline glaze to the high-wear-resistance dry particles is 70: 20-70: 30.

preferably, the chemical composition of the matte crystal glaze comprises: by mass percentage, the loss on ignition is 7.0-7.2%, and SiO is₂ 48.5～50.0%，Al₂O₃ 19.5～20.5%，Fe₂O₃ 0.15～0.18%，TiO₂ 0.08～1.0%，CaO 9.0～9.5%，MgO1.4～1.6%，K₂O 1.7～1.9%，Na₂O 3.9～4.1%，ZnO 4.8～5.2%。

Preferably, the chemical composition of the high-abrasion-resistance dry particles comprises: by mass percentage, 0.35-0.4% of loss on ignition and Na₂O 3.2～3.4%，SiO₂ 53.5～54.5%，Al₂O₃ 18.6～19.2%，CaO 14.8～15.3%，ZnO 4.0～5.0%，K₂O 2.0～2.5%，SrO 0.5～0.8%，MgO 0.30～0.45%，BaO 0.15～0.20%。

Preferably, the grain composition of the high wear-resistant dry particles is as follows: 0% above 100 mesh, 88-92% below 100-250 mesh, and 8-12% below 250 mesh.

Preferably, the specific gravity of the high wear-resistant dry particles is 1.30-13.5, and the glaze spraying amount is 250-300 g/m²。

On the other hand, the invention also provides a high wear-resistant antifouling ceramic thick plate obtained by any one of the preparation methods.

The specification of the high-wear-resistance antifouling microcrystal decorative ceramic thick plate is 760-1600 mm multiplied by 1800-3600 mm multiplied by 5.5-20.5 mm in large size. The method of the invention can prepare series ceramic thick plate products with surface area of 3 square meters, such as 1600mm multiplied by 3600mm multiplied by 15.5mm, 1200mm multiplied by 2400mm multiplied by 13.5mm, 1200mm multiplied by 2400mm multiplied by 5.5mm, 760mm multiplied by 2550mm multiplied by 13.5mm, 900mm multiplied by 1800mm multiplied by 10.5mm, 900mm multiplied by 1800mm multiplied by 5.5mm and the like.

Drawings

Fig. 1 is a flow chart of the preparation process of the microcrystalline decorative ceramic slab with high wear resistance and antifouling property according to an embodiment of the invention.

FIG. 2 is an XRD pattern of samples of different alumina contents.

FIG. 3 is an XRD pattern of calcined bauxite.

Figure 4 is an XRD pattern of samples of different firing cycles.

FIG. 5 is an SEM photograph of samples for different firing cycles.

Fig. 6 is a green body recipe sintering temperature range.

FIG. 7 is a comparison diagram of green body powder and general ceramic body powder magnified 50 times according to one embodiment of the present invention, wherein (a) is green body powder according to the present invention, and (b) is general ceramic body powder.

FIG. 8 is a schematic representation of the fines and hopper walls after dry blending.

FIG. 9 is a color cake diagram of wet ball milling color mixing and dry ball milling color mixing, wherein the first row is wet ball milling color mixing and the second row is dry ball milling color mixing.

FIG. 10 is a graph showing the relationship between the powder breakage rate after dry blending at 20 rpm with the dry blending time, in which 1kg of a coloring material and 250kg of a base material are mixed.

FIG. 11 is a graph showing the relationship between the powder breakage rate after dry blending for 10 minutes using 1kg of a colorant and 250kg of a base material, and the dry blending speed.

FIG. 12 is a side view and a front view of a full body ceramic slab, wherein (a) is a side view of the ceramic slab and (b) is a front view of the ceramic slab.

FIG. 13 is a schematic view showing the melting temperature range of a matte crystalline glaze, wherein (a) is an image at 1131 ℃, (b) is an image at 1171 ℃, (c) is an image at 1206 ℃, and (d) is an image at 1236 ℃.

Fig. 14 is an SEM image of the matte crystalline glaze surface layer, in which (a) is an SEM image of the soft glaze surface layer with a scale of 1 μm, and (b) is an SEM image of the soft glaze surface layer with a scale of 200 nm.

FIG. 15 is an SEM image of a matte crystalline enamel layer.

Fig. 16 is an SEM image of a matte crystalline underglaze layer.

FIG. 17 is a graph of the melting temperature of highly abrasion resistant dry pellets.

FIG. 18 is an XRD pattern of a glazed surface of a highly wear-resistant and anti-fouling ceramic slab according to an embodiment of the present invention, wherein FIG. (a) is an XRD pattern of a glazed surface of a general fully polished tile, and FIG. (b) is an XRD pattern of a glazed surface of a product according to the present invention.

Fig. 19 is SEM photo of glaze of ceramic slab with high abrasion resistance and anti-fouling according to an embodiment of the present invention, wherein (a) SEM photo of glaze of general marble tile, and (b) SEM photo of glaze of product of the present invention.

FIG. 20 is a diagram of the brick surface effect of the microcrystal decorative ceramic thick plate with high wear resistance and antifouling property obtained in the embodiment of the invention.

FIG. 21 is a diagram showing the effect of the present invention in example 2, in which there are a few pinholes and miliaria on the brick surface.

Detailed Description

The present invention is further illustrated by the following examples, which are to be understood as merely illustrative and not restrictive. The following percentages are by mass unless otherwise specified. In the present invention, the "matte crystalline glaze" may also be referred to as "matte glaze". The highly abrasion resistant dry grain soft glaze may also be referred to as "dry grain glaze".

The following description shows a method for preparing a microcrystalline decorative ceramic slab with high wear resistance and antifouling property with reference to fig. 1.

First, green body powder is prepared.

One of the technical problems to be solved in the process of preparing the thick ceramic plate is that the strength of a blank body and the bending of the blank body are not deformed. Among the factors that affect strength are the amount of glass phase, porosity, amount of crystals, and the like. As the number of crystals increases, the number of grain boundaries between the crystals increases, and the crack deflects across the grain boundaries, consuming more energy, resulting in increased failure strength. According to the invention, the test proves that the content of the aluminum oxide in the formula is improved, and the content of mullite and corundum crystals is improved. The invention mainly increases the content of aluminum oxide in the formula of the green body by increasing the addition of calcined bauxite. Preferably, the alumina content of the green body powder is 28.5-29.5 wt%.

In some embodiments, the chemical composition of the green body powder for preparing the high-strength full body ceramic thick plate green body comprises: by mass percentage, the loss on ignition is 4.8-5.0%, and SiO is₂ 57.5-58.5%，Al₂O₃ 27.8-28.5%，Fe₂O₃ 0.75-0.80%，TiO₂ 0.58-0.62%，CaO 0.35-0.40%，MgO 1.1-1.2%，K₂O 2.2-2.4%，Na₂O 2.5-2.7% 。

Various formulas are selected and debugged in the specific test process.

TABLE 1 chemical composition (wt%) of three different formulations of alumina content

The most representative of the three formulas are the three formulas.

TABLE 2 physicochemical properties of three different formulations of alumina content

The raw materials for preparing the green body powder material can comprise: selecting sodium stone powder, gold middlings, Shaoguan ball clay, water-washed ball clay, black talc, calcined bauxite, potassium aluminum sand, bentonite and Zhongshan black mud.

In some embodiments, the raw materials for the green body powder may include: by weight, 16.5-17.5 parts of selected sodium stone powder, 15.5-16.5 parts of gold middling, 5-7 parts of Shaoguo ball clay, 11-13 parts of water-washed ball clay, 2.5-3.5 parts of black talc, 16-18 parts of calcined bauxite, 19.5-20.5 parts of potassium aluminum sand, 1.5-2.5 parts of bentonite and 6.5-7.5 parts of Zhongshan black mud. The composition of the raw materials of the three different formulations of alumina content is shown in table 3.

TABLE 3 raw material composition (unit: g/part by weight) of three different formulations of alumina content

As can be seen from tables 1, 2 and 3, as the amount of calcined bauxite increased, the amount of alumina increased from 23.8% to 29.04%, the change in the dry strength and shrinkage of the green body was small, and the flexural strength increased from 62.19MPa to 74.01 MPa.

As can be seen from fig. 2 and table 4, the formulations with different alumina contents are composed of quartz, mullite, corundum and amorphous phase after firing, and as the alumina content increases, the contents of mullite and corundum phase in the formulations increase. From Griffith's strength theory, it is known that the strength of the porcelain body increases with its modulus of elasticity. Due to the elastic modulus (40X 10) of corundum⁴MPa) is much greater than mullite (9.8X 10)⁴MPa) and amorphous phase (7.2X 10)⁴MPa) and thus the flexural strength increases.

TABLE 4 Crystal phase (wt%) for three different formulations of alumina content

Combining the XRD pattern of the calcined bauxite in FIG. 3 and the semi-quantitative analysis of the calcined bauxite in Table 5, it can be seen that the calcined bauxite is mainly composed of corundum and mullite crystals, and thus is advantageous for increasing the crystal phase content. This is consistent with the present invention's increased alumina content in the green body formulation by the addition of calcined bauxite as described above.

TABLE 5 semi-quantitative analysis (wt) of calcined bauxite

The prolonged heat preservation time of the high-temperature zone has great influence on the mullite content, the grain size and the density of a green body. The test discusses the influence of different firing periods on the flexural strength, phase composition and other aspects of the green body on the basis of the formula No. 3. The experiment adopts roller kiln sintering, the sintering period is 75min and 120min respectively, and the sintering temperature is 1230 ℃. Flexural strength, water absorption, bulk density, phase composition and semi-quantitative analysis of the phases of the samples at different firing times are shown in tables 6, 7 and fig. 4, respectively.

TABLE 6 Effect of firing time on Green body Performance

As can be seen from Table 6, as the firing time was increased from 75min to 120min, the flexural strength of the green body increased from 66.58MPa to 74.01MPa, the water absorption rate decreased and the bulk density decreased from 2.42g/cm³Lifting to 2.44g/cm³。

TABLE 7 semi-quantitative analysis (wt%) of phases of samples of different firing periods

As can be seen from FIG. 4 and Table 7, the crystal phases of the samples consisted of quartz, mullite, and corundum phases at different firing times. Along with the increase of the sintering period, the mullite content is obviously increased, and the quartz phase content is reduced. As can be seen from the SEM photographs of fig. 5 showing different firing times, the amount of pores in the green body is significantly reduced with the extension of the firing period, which is advantageous for the discharge of internal gas and the realization of dense sintering. Thus, as firing time increases, the bulk density and flexural strength of the green body increases.

In conclusion, the content of the aluminum oxide in the formula of the blank is increased, and the flexural strength of the product is increased along with the increase of the content of the aluminum oxide. This is because, with an increase in the alumina content, the corundum content and the amorphous phase content in the fired product increase. From Griffith's strength theory, it is known that the strength of the porcelain body increases with its modulus of elasticity. Modulus of elasticity of corundum (40X 10)⁴MPa) is much greater than mullite (9.8X 10)⁴MPa) and amorphous phase (7.2X 10)₄MPa). In some embodiments of the invention, the content of Amorphous-Amorphous phase after the green body is fired is 46-55%. The crystal phase content is 45-54%, and the Quartz SiO mainly comprises 17-24%₂17-24% Mullite-Mullite (3 Al)₂O₃·2SiO₂) And 3-11% Corundum-Corundum Al₂O₃。

In some embodiments, the green body powder is prepared by: the raw materials are weighed according to the proportion and put into a ball mill for ball milling to obtain slurry, and the slurry is pulverized (for example, powder is sprayed by a spray tower) to obtain blank powder. The moisture range of the blank powder is controlled to be 7.2-8.0%. In some embodiments, the specific gravity of the slurry may be 1.70 to 1.72. By controlling the slurry within this specific gravity range, the bulk density of the powder can be increased and the number of hollow particles can be reduced. By improving the volume weight of the powder, the powder is solid, and is less likely to be crushed in the transfer process, and the flowability is better.

Due to the different slurry fineness and the different surface energy of the particles, the firing temperature difference of the formula is larger finally. In some specific experiments of the present invention, the effect of ball milling time on the specific gravity of the slurry, the oversize (250 mesh), green body shrinkage and water absorption was investigated. The results are shown in Table 8.

TABLE 8 Properties at different milling times

As can be seen from table 8, when the ball milling time was 10min, the particles were coarse, the oversize was 6.49%, the water absorption was 4.11% (> 0.5%), and the degree of vitrification of the green body was low; when the ball milling time is increased to 30min, the screen residue is 0.21%, the granularity is obviously reduced, the water absorption is reduced to 0.077%, and the ceramic degree of the blank is greatly improved. This is due to the fact that as the ball milling time increases, the particles are under the grinding and impact of the pebbles, resulting in a decrease in particle size. And the sintering driving force is increased along with the reduction of the granularity, the diffusion distance of atoms is shortened, the solubility of the particles in a liquid phase is improved, the sintering process is accelerated, and meanwhile, the defects of the interior and the surface of the particles are increased under the grinding of the ball stone, so that the sintering performance of the powder is improved. Therefore, with the reduction of the particle fineness, the firing temperature of the formula is reduced, the degree of vitrifying of the green body is better, the higher the density is, and the shrinkage and the water absorption of the green body are respectively increased and decreased. In order to ensure that the ceramic degree of the blank is good, the cutting performance is excellent, and the sintering shrinkage meets the actual production requirement, the screen residue of the slurry is preferably 0.3-0.5% (250 meshes) and is most suitable.

The formula, chemical composition and sintering temperature range of the blank confirmed by pilot test are respectively shown in the following by combining the experimental results and actual production. The firing system 2 is a firing system before adjustment, the tortoise back of the blank is very bad (7-8 mm), and the firing system 1 is a curve corresponding to new operation according to the adjustment of the process. The main changes are as follows: a. the sintering period is prolonged. The longer the firing period, the stronger the diffusion of the components in the glaze, the more the reaction of the blank glaze is sufficient, the better the development of the intermediate layer, the uniform thermal stress among the blank glazes is promoted, the bonding property of the blank glaze is improved, and the effect of improving the deformation is achieved; b. the flatness of the green brick can be effectively adjusted by uniformly adjusting the opening degree of the upper and lower quenching pipes. For the ceramic thick plate with the thickness of 13.5mm, 15.5mm or even 20.5mm, if the blank is not oxidized well in the whole firing process, the phenomenon of black core exists, and the flatness of the blank can be out of control. The time of the oxidation period is properly prolonged, the upper temperature and the lower temperature of the oxidation area are kept in a relatively close range as much as possible, the purpose can be achieved by increasing the heights of the surface gun, the fire barrier and the fire baffle, and the upper surface shrinkage and the lower surface shrinkage of the green body are kept synchronous basically. As can be seen from FIG. 6, the sintering temperature range is within 1260-1290 ℃ range, and the sintering temperature range is wider.

As the size of ceramic products increases, higher demands are made on the strength of the products in order to avoid breakage during operation. When the strength of the green body is low, breakage is easily caused in the forming, conveying and the like processes. The strength of the dried green body is improved by adding a proper amount of green body reinforcing agent. In some embodiments, the green body strengthening agent is preferably added in an amount of 0.2 to 0.6%. Table 9 shows the effect of the addition of the green strength agents of 0%, 0.2%, 0.4% and 0.6% on the green strength.

TABLE 9 Effect of enhancer addition on green body Strength

As can be seen from table 9, the wet green strength did not change significantly with the increase in the reinforcing agent, and the dry green strength gradually increased. When the addition amount is more than 0.2%, the increase in dry strength is insignificant. This is because ceramic particles rely primarily on van der waals forces and capillary forces generated by the presence of small amounts of moisture between the particles when no reinforcing agent is added. When the reinforcing agent is added, the green body particles are wrapped by the high polymer material, and at the moment, hydrogen bond action is generated among the green body particles besides Van der Waals force and capillary force, so that the dry strength of the green body is enhanced. When the addition amount of the reinforcing agent is increased, hydrogen bonds are increased, and the strength of the dried blank is further enhanced. Since the increase in the strength of the dried body is insignificant when the addition amount is more than 0.2%, the addition amount of 0.2% is most preferable in view of the production cost.

Meanwhile, by adjusting parameters such as temperature, air quantity and the like of spray granulation, the powder with smooth particles, good fluidity and high particle strength is prepared. When the temperature of the kiln reaches 500-580 ℃, the reinforcing agent in the green body is completely carbonized and lost, and the performance of the ceramic tile cannot be influenced.

The better the powder forming performance, the stronger the adaptability to the press. Meanwhile, the good powder fluidity is beneficial to the uniformity and the whole body effect of the material distribution of the press. The invention is mainly researched from the following aspects:

(1) improve the wet strength of the powder

The clay in the blank powder raw material greatly influences the wet strength of the powder and the whiteness of the product. Clay is a mixture of many mineral particles of different sizes and different physical, chemical and mineralogical properties, has plasticity and binding property, and is a basic raw material for ceramic production. When the iron and titanium contents in the clay raw material are higher, the whiteness is obviously reduced after firing. Several representative clays that can be used in the formulations are compared in terms of whiteness, flow rate, wet green strength, and dry strength, and the specific results are shown in table 10.

TABLE 10 basic physical Properties of Clay

Wherein: wherein 1) Shaoguan ball soil and water washing ball soil: is prepared from black mud, kaolin, sodium humate, etc. Ball clay is prepared by desanding, acid washing, iron removing and filter pressing; 2) High-strength washing mud: the raw ore mud is processed by washing with water to remove sundries such as branches and the like; 3) high-white bentonite: the Henan Xinyang high-whiteness bentonite is selected, so that the reinforcing effect is good; 4) zhongshan black mud: the raw ore black mud in the Zhongshan area is used. According to table 10, it is reasonable to select the shaoguan ball clay and bentonite for formulation adjustment.

(2) Increase the volume weight of powder and reduce hollow particles

The volume weight of the powder is improved, the powder is solid, the powder is not easy to break in the transfer process, and the flowability is good. The method is mainly achieved by increasing the specific gravity of the slurry to 1.70-1.72 and adjusting parameters such as the temperature and the air quantity of the spray tower for granulation.

(3) Reasonable particle size distribution

In some embodiments, the green body powder grain composition comprises: 8-18% above 30 meshes, 30-60 meshes: 70-80%, 60-80 mesh: 6-15% and less than 6% below 80 meshes.

In a specific test process, the invention compares the flowability of powder under different particle size compositions. Table 11 below shows a comparison of the flowability of the powder compositions of different green bodies. As can be seen from Table 11, the larger the volume weight of the powdery material, the larger the particle size of 30 mesh or larger, and the better the flowability.

TABLE 11 comparison of the flowability of the powders at different particle sizes

FIG. 7 is a comparison of green body powder and conventional ceramic green body powder at 50 times magnification according to one embodiment of the present invention. As can be seen from FIG. 7, the green body powder used in the present invention is mostly spherical, smooth in appearance, and good in flowability, which is beneficial to the distribution and molding of the press. The common ceramic tile powder is irregular in shape, and the surface of the common ceramic tile powder is provided with more burrs formed by broken fine powder, so that the powder is strong in adhesion, poor in fluidity and easy to form powder balls.

According to preliminary conjecture, the ceramic plate stress is caused by the fact that a ceramic material blank is composed of crystals, non-crystals and pores into a non-homogeneous body, and the stress distribution difference is caused by the uneven distribution of phases and pores, so that the density and the uniformity of the blank are improved, and the improvement of the stress distribution of the ceramic material is greatly facilitated. The breakage of the architectural ceramic material along the crystal is mainly used when the architectural ceramic material is broken, and the crystal in the blank body is still kept complete when the product is broken, so the content of the crystal phase and the bonding strength between the crystal phases determine the strength of the ceramic tile and the performance of later processing; the higher the crystalline phase content in the product is, the higher the green body strength is, and the later-stage processing performance is also improved. The heat preservation time of a high-temperature area is prolonged when the ceramic material is sintered, and the generation of mullite, feldspar and other crystals in the blank body can be promoted, so that the mechanical strength of the finished product is improved. In addition, the content of free quartz and the grain size of the free quartz in the sintered blank also influence the processing performance of the ceramic material, and because the quartz can generate crystal transformation at 574 ℃, in the cooling process, when the high-temperature quartz is transformed into the low-temperature quartz, cracks can be generated along the quartz grains along with the shrinkage of the grain size, so that the mechanical processing performance of the ceramic product is reduced. Three basic raw materials of ceramics: the mullite-containing ceramic material comprises clay, quartz and fluxed raw materials, wherein a mullite crystal phase generated after the clay is sintered can improve the mechanical strength, thermal stability and chemical stability of a sintered product. The clay raw material with low content of free quartz and low loss after firing is selected, so that the improvement of the processing performance of the ceramic product can be greatly promoted; meanwhile, in the raw material mixing ball milling process, the ball milling time is properly prolonged, the quartz in the raw materials is milled to be finer, and the size of cracks of the burnt free quartz in the crystal form conversion process is controlled, so that the mechanical strength of the product is improved. According to the invention, by selecting proper blank powder chemical components, particle grading, ball milling process and the like, the obtained powder has good forming performance and stronger adaptability to a press, and meanwhile, the good powder fluidity is beneficial to the uniformity and the whole body effect of the material distribution of the press.

In addition, the natural stone has consistency in external appearance and internal appearance, and the traditional ceramic tile is difficult to achieve in effect, so that huge contrast formed by the decorative effect of blanks with different colors inside and the ceramic tile glaze is obviously seen when the natural stone is subjected to treatment such as grooving, chamfering and arc in later-stage deep processing. In order to solve the problem of inconsistent inside and outside of the thick plate, the color of the blank is close to the surface effect or even consistent through a color mixing mode.

TABLE 12 comparison of color mixing of wet ball mill and dry colorant

At present, the color mixing process mainly comprises wet ball milling color mixing and dry color mixing, and the ratio of the color mixing quality of the wet ball milling color mixing and the dry color mixing is shown in table 12. As can be seen from Table 12, although the dry blending method has the advantages of convenient production conversion, no slurry pool occupation, etc., the dry blending method also has the disadvantages of color variation of powder, easy layering in press molding, etc.

Table 13 shows the volume weight, particle fineness and flow rate of the powder before and after dry-blending. As can be seen from Table 13, the amount of fine powder of 80 mesh or less increased significantly after the dry-blending step, resulting in poor flowability, and the poor flowability of the fine powder caused the powder to stick to the roller wall and cause delamination (see FIG. 8). From FIG. 9, 3% pigment is added to wet and dry color-mixed color cakes (first row wet ball milling color mixing, second row dry ball milling color mixing), the wet ball milling color-mixed powder is better colored and has no white particles, while the dry color-mixed powder is poorer colored and is mixed with white particles which are not wrapped by the pigment. Therefore, wet ball milling color mixing will not result in increased powder subdivision and poor flowability. Meanwhile, the powder is better colored.

TABLE 13 Properties of the powders before and after Dry blending

FIG. 10 is a graph showing the relationship between the powder breakage rate after dry-mixing of 1kg of a coloring material and 250kg of a base material at a stirring speed of 20 rpm as a function of the dry-mixing time, and FIG. 11 is a graph showing the relationship between the powder breakage rate after dry-mixing of 1kg of the coloring material and 250kg of the base material for 10 minutes as a function of the dry-mixing speed. It is known that the breakage rate of the powder material increases along with the extension of the dry mixing time or the increase of the dry mixing rotating speed, and the wet ball milling color mixing adopts the slurry color mixing and then the spray granulation mode does not increase the breakage of the powder material.

According to the analysis, considering that the requirement of large-size products on the powder forming performance is higher, a wet ball milling color mixing process is selected.

Then distributing the blank powder and pressing into a blank. The strength of the formed blank is 0.4-0.6 MPa. The size of the blank body can be 760-1600 mm in width, 1800-3600 mm in length and 5.5-20.5 mm in thickness. For example, 1600 mm. times.3600 mm. times.15.5 mm, 1200 mm. times.2400 mm. times.13.5 mm, 1200 mm. times.2400 mm. times.5.5 mm, 760 mm. times.2550 mm. times.13.5 mm, 900 mm. times.1800 mm. times.10.5 mm, 900 mm. times.1800 mm. times.5.5 mm. The surface area may be up to 5.76 square meters. The thickness may be 13.5mm, 15.5mm or even 20.5 mm. In some embodiments, a full body ceramic slab blank is shown in FIG. 12.

In some embodiments, the green body powder is distributed in a manner completely different from the conventional grid distribution, but a belt-in type distribution is adopted. If the ceramic plate with the ultra-large specification of 1600mm multiplied by 3600mm and the like adopts the traditional grid distribution, the grid size is very large, the rigidity of the ceramic plate is difficult to ensure, the packing thickness is uneven, and the dimensional precision of the green brick cannot be ensured. The problem of the belt stretching-in cloth does not exist. 1200 ✕ 2400mm, 760x2550mm and 900mmx1800mm are traditional grid cloth, and have the advantages of small size, simple operation and better size control.

The green body may then be dried, for example in a drying kiln. The strength of the dried green body is 2.8-3.5 MPa. The drying temperature can be 200-250 ℃, the drying time can be 90min, and the moisture of the dried blank is controlled within 0.4%.

Subsequently, a cover glaze is applied on the dried green body. The overglaze can be applied by spraying glaze. In some embodiments, the overglaze is applied at an amount of 520-580g/m²。

Preferably, the chemical composition of the overglaze may include: IL (ignition loss) 4-5% and SiO in percentage by mass₂ 50.7～51.5%，Al₂O₃ 29～30.5%，Fe₂O₃ 0.2～0.3%，CaO 0.35～0.5%，MgO 0.1～0.2%，K₂O 5.5～6.5%，Na₂O 2.0～2.5%，ZrO₂ 5.9 to 6.5 percent. Tests show that the overglaze formula has good color development and glaze effect.

However, because the firing period and the high-temperature heat preservation time of the thick ceramic plate product are longer, the temperature of the overglaze formula is slightly lower, the whiteness is deteriorated, and a few pinholes and miliaria appear on the brick surface.

Further preferably, the chemical composition of the overglaze may comprise: by mass percentage, the burning loss of IL is 4-5%, and SiO is₂ 50.9～51.3%，Al₂O₃ 29.8～30.3%，Fe₂O₃ 0.2～0.3%，CaO 0.35～0.45%，MgO 0.1～0.15%，K₂O 5.6～6.0%，Na₂O2.0～2.2%，ZrO₂ 6.1 to 6.4 percent. By increasing the contents of the high-aluminum material and the zirconium silicate on the basis of the original overglaze formula, the firing temperature of the overglaze is correspondingly increased, and the defects of miliaria, pinholes and the like on the surface of the brick in the production process are effectively solved. In some embodiments, the firing temperature of the overglaze is 1200 to 1250 ℃.

The soft glaze can be applied after the pattern is printed on the green body with the overglaze by ink-jet printing. The soft glaze layer can also be directly coated on the overglaze layer. The ink can be printed by a digital ink-jet printer. The ceramic ink used may be blue, reddish brown, orange, golden yellow, lemon yellow, black, red, etc. The specific decorative pattern, texture and color effect are determined according to the design requirements.

The blank printed with the ink-jet pattern is then dried.

The application range of the ceramic thick plate is expanded to occasions where the cupboard, the dining table top and the like contact with food, and the surface is required to have the performances of high temperature resistance, scratch resistance, acid and alkali resistance, easy cleaning, no toxicity and the like. Therefore, in the development of glaze, the materials need to be selected and developed from the following points: 1) safety and sanitation: can be in direct contact with food; 2) fireproof and high temperature resistant: the direct contact with high temperature objects can not deform; 3) impermeability: the porcelain is completely vitrified, stains cannot permeate, and no space is provided for breeding bacteria; 4) scratch resistance: the Mohs hardness exceeds 5 grade, and the scratch can be resisted; 5) corrosion resistance: resistance to various chemicals, including solutions, disinfectants, acid and base chemicals, etc.; 6) easy cleaning: the cleaning can be realized only by wiping with a wet towel, no special maintenance requirement is needed, and the cleaning is simple and quick. Meanwhile, the flatness of the thick ceramic plate is required to be met.

And then applying high-wear-resistance dry-particle soft glaze on the surface of the dried blank. The high-wear-resistance dry particle soft glaze comprises high-hardness wear-resistance dry particles and matte crystal glaze. In some embodiments, the mass ratio of the matte crystalline glaze to the high abrasion resistant dry particles is 70: 20-70: 30. the high wear-resistant antifouling ceramic thick plate with excellent performance can be prepared.

The matte crystal glaze in the invention is a matte crystal protection glaze with low glossiness after being fired, and mainly plays the roles of a suspending agent and an inclusion. Has soft light effect, fine hand feeling, wide firing range and the glossiness of the fired product is 6 to 9 degrees. Preferably, the matt crystalline glaze contains anorthite crystals. Calcite and calcined kaolin are introduced into a raw material formula of the matt glaze, a large amount of anorthite crystals are separated out from a glaze layer through firing, light rays are diffusely reflected, and the matt effect is formed. Through a large number of comparative experiments, the formula of the matt crystalline glaze is finally determined.

Some examplesIn one embodiment, the chemical composition of the matte crystalline glaze comprises: by mass percentage, IL (ignition loss) 7.0-7.2%, SiO₂ 48.5～50.0%，Al₂O₃ 19.5～20.5%，Fe₂O₃ 0.15～0.18%，TiO₂ 0.08～1.0%，CaO 9.0～9.5%，MgO1.4～1.6%，K₂O 1.7～1.9%，Na₂O 3.9～4.1%，ZnO 4.8～5.2%。

The soft glaze is prepared into a sample, and the melting temperature range is measured to be 1131-1231 ℃, and is shown in figure 13. It is known that the glaze melts from 1131 ℃ and completely melts at 1231 ℃, and the melting range is wide (about 100 ℃) and is beneficial to firing.

The XRD scanning result of the matt crystalline glaze can show that the matt crystalline glaze mainly comprises calsodic plagioclase and partial mullite crystalline phase. The hardness of the albite anorthite is 6, and the surface is compact. The detection shows that the abrasion resistance of the matte crystalline glaze (namely the soft glaze) can reach four grades (6000 revolutions).

The surface layer electron microscope scanning photograph of the soft glaze is shown in figure 14, and the middle and lower layer electron microscope scanning photographs are shown in figures 15 and 16. As can be seen from the figure, a large number of needle-shaped or columnar anorthite crystals exist in the glaze layer, are uniformly crystallized, are interwoven in a net shape and are distributed on the whole brick surface, so that light rays are diffusely reflected to form a matte effect. Because the crystals are separated on the middle layer and the lower layer of the glaze, the change of the glossiness caused by surface abrasion after long-term use is avoided.

At present, the domestic glaze technology is not advanced, the frits for preparing dry particles in the market are basically common frits, and the low-temperature glass phase is too much, so that the ceramic tile glaze is poor in wear resistance and small in hardness, the wear resistance level of the ceramic tile glaze is generally 1-2 levels, and the ceramic tile glaze is easy to wear. The high-hardness wear-resistant glaze imported from Italy Caribbean glaze company can achieve 3-4 grade of product wear resistance, and although the wear resistance grade is better than that of similar products, the use requirement of the invention is still difficult to meet. Aiming at the defects of the wear resistance and hardness of the existing imported fritted glaze, the invention provides a brand-new technical innovation assumption for further improving the wear resistance of the thick ceramic plate and realizing the localization of high-hardness wear-resistant glaze. Firstly, a special frit microcrystallization treatment process is adopted, and the common characteristics of the frit are kept and the microcrystallization effect of the frit is achieved through a specific process route; secondly, preparing frit and matte glaze slurry into glaze according to a certain ratio, applying the glaze on a ceramic tile blank, performing high-temperature densification at 1230 ℃, crystallizing and separating out high-hardness crystals by using frit microcrystals as crystal nuclei, and simultaneously keeping good permeability, stereoscopic impression and toughness of the glaze, thereby obtaining the glaze effect with high hardness, wear resistance and three-dimensional transparency.

The performance of the high wear-resistant dry particles as a multi-phase material is not only dependent on the types of the microcrystals, but also dependent on the size, the quantity and the distribution of the microcrystals, and defects of cracks, bubbles, impurities and the like of a matrix. In the case of the same formulation system, the preparation process of the frit has a great influence on the apparent hardness, and a more ordered and denser structure can obtain higher apparent hardness. When the composition and internal structure of the crystal are fixed, the smaller the grain size of the crystal phases constituting the frit is, the more densely the arrangement is, and the higher the (apparent) hardness of the frit is.

In some embodiments, the melting process parameters of the high wear-resistant dry particles are as follows: heating the raw materials to 1580 ℃ of 1450-; then, the temperature is reduced to 1280-1360 ℃ at the speed of 0.5-3 ℃/min; then continuously cooling to 1250-; then raising the temperature to 1300-1380 ℃ at 0.5-3 ℃/min. According to the invention, by setting a reasonable temperature curve (see figure 17), the heat preservation time is properly prolonged in a nucleation area, so that a large amount of crystals are nucleated and precipitated; the heat preservation time is properly shortened in the crystallization area to prevent the crystal from excessively growing, then the temperature is rapidly raised, the melt fluidity is improved, meanwhile, the corrosion of the melt to the crystal is reduced, and a part of the crystal is preserved to flow out together with the melt to prepare the fusion cake. Therefore, a reasonable temperature system is the key point for ensuring that the microcrystalline frit with large crystal quantity, small grain size and compact arrangement is obtained.

TABLE 14 main process parameters of high abrasion resistance dry grain microcrystallization

By the microcrystallization frit melting process, the erosion time of crystals is properly adjusted, so that most of the crystallite phase mainly comprising anorthite is controlled to be 0.1-0.3 mu m and not within the range of visible light wavelength (0.38-0.78 mu m); on the other hand, the refractive index of the anorthite is 1.525 to 1.535, and is close to the refractive index of the glass phase (1.517 to 1.152). Therefore, the microcrystalline frit has good transparency. Meanwhile, the high-hardness dry particles are controlled to crystallize in the frit, are distributed uniformly, and can ensure the stability of the wear-resisting grade.

In some embodiments, the chemical composition of the highly attrition resistant dry pellets comprises: by mass percentage, IL (loss on ignition) 0.35-0.4%, Na₂O 3.2～3.4%，SiO₂ 53.5～54.5%，Al₂O₃18.6～19.2%，CaO 14.8～15.3%，ZnO 4.0～5.0%，K₂O2.0-2.5%, SrO 0.5-0.8%, MgO 0.30-0.45%, and BaO 0.15-0.20%. The introduction of more CaO and Na2O promotes the growth of the albite anorthite crystal.

The high-wear-resistance dry particle soft glaze, namely the mixture of the high-wear-resistance dry particle and the matte glaze slurry, has stable physical properties, namely good suspension property and fluidity, in order to ensure stable use. The particle size of the particles is determined to be critical, the particles are too large and are easy to precipitate, and the particles are too small and are completely wrapped by the glaze slurry after being sintered, so that the purpose and the effect of the experiment cannot be achieved. Because the main characteristic of the invention is that after the glaze with dry particles (i.e. the glaze with high abrasion resistance and soft light) is sprayed, dense convex particles are formed on the surface of the product so as to form a low-light effect, the dry particles need to be at high temperature and the particles can not be coarse or fine. Through experiments, the particle composition of the high-wear-resistance dry particles can be as follows: 0% above 100 mesh, 88-92% below 100-250 mesh, and 8-12% below 250 mesh. In some embodiments, the grain composition of the high abrasion resistant dry grain glaze is: 0 percent above 100 meshes, 89.14 percent below 100 meshes and 250.37 percent below 250 meshes. And (3) carrying out crystal nucleus crystallization on the high-hardness wear-resistant dry particles, taking the frit microcrystals as crystal nuclei to crystallize and precipitate high-hardness crystals, and simultaneously keeping good permeability of the glaze.

In some embodiments, the high-wear-resistance dry-particle soft glaze is applied by glaze spraying. In some embodiments, the high-wear-resistance dry particle soft glaze has a cloth application amount of 250-300 g/m²。

Because the dry particles are applied by adopting a glaze spraying mode, the dry particles need to be prepared into glaze slip and have glaze spraying performance. The dry particle glaze slurry needs to have good suspension property and fluidity of the dry particles. The rubber roller printing ink is a printing medium with excellent rheological property for roller printing, has good suspension property and dispersibility, and has a flow rate of 10-12 s. The matte glaze slip is a matte protective glaze with lower glossiness after firing, and mainly plays a role of a base material in the invention, so that dry particles are better fused together. The flow rate of the matte glaze slip is 40-80 s. Proper amount of dry grains and roller printing oil are added into the matte glaze slip, and a small amount of leveling agent is added to adjust the flow rate of the slip. The flow rate of the dry particle glaze slip is preferably 20-30 s, the dry particle glaze slip with the flow rate has good glaze spraying performance, and dry particles sprayed on the surface of a brick can be more uniform. The leveling agent can be prepared from alkylphenol polyoxyethylene and hydrophobic silicon dioxide. Wherein the percentage content of the alkylphenol polyoxyethylene is 70-80%, the percentage content of the hydrophobic silicon dioxide is 20-30%, and the flow rate of the prepared flatting agent is 40-80 s. The dry particle glaze slip of the formula has good fluidity and high viscosity, and particles are not easy to precipitate. In the preferable scheme, the flow speed of the dry particle glaze slip is 20-25 s.

In some embodiments, the high abrasion resistant dry-particle glaze slip comprises: 30-40 parts of matte crystalline glaze, 10-15 parts of high-wear-resistance dry particles, 10-15 parts of TS268S (leveling agent) and 35-40 parts of TS268P (stamp-pad ink). The dry particle glaze slip of the formula has good fluidity and high viscosity, and dry particle particles are not easy to precipitate.

In some embodiments of the invention, high-hardness wear-resistant dry particles and matte crystal glaze slurry are mixed according to a certain proportion, then rubber roll printing oil and a leveling agent are added to disperse and adjust the slurry performance, then a high-pressure pump water jet machine large-aperture spray head glaze spraying mode is adopted to uniformly apply a layer of thin dry particle glaze on the brick surface, fine particles are densely distributed on the brick surface after high-temperature sintering, high-temperature densification is carried out at 1230 ℃, high-hardness crystals are separated out by crystallization with a frit as a crystal nucleus, and good permeability, three-dimensional effect and toughness of the glaze are maintained, so that a high-hardness, wear-resistant and three-dimensional transparent glaze effect is obtained.

And then drying the blank body coated with the glazed high-wear-resistance dry-particle soft glaze, and then sintering, edging, grading and packaging. In some embodiments, the firing temperature is 1200 to 1290 ℃ and the firing period is 75 to 180 min.

The product of the invention is greatly improved in the aspects of physical and chemical properties such as wear resistance, corrosion resistance and the like, and reaches the food-grade safety level of daily porcelain.

The present invention will be described in detail by way of examples. It is also to be understood that the following examples are illustrative of the present invention and are not to be construed as limiting the scope of the invention, and that certain insubstantial modifications and adaptations of the invention by those skilled in the art may be made in light of the above teachings. The specific process parameters and the like of the following examples are also only one example of suitable ranges, i.e., those skilled in the art can select the appropriate ranges through the description herein, and are not limited to the specific values exemplified below.