1. A method for manufacturing glazed tiles by adopting solid powder is characterized in that: the method comprises the following steps:

s1, placing the solid powder into a press, and pressing under the action of a mould to form a green brick base layer;

s2, drying the green brick base layer to ensure that the water content is not more than 0.3%;

s3, uniformly spraying the ceramic slurry on the upper surface of the green brick base layer to form a green brick surface layer to obtain a green brick;

s4, drying the green brick;

s5, applying base coat on the surface of the green brick;

s6, surface decoration;

s7, applying surface glaze;

and S8, firing to obtain the glazed tile.

2. The method of claim 1 for making a glazed tile from solid powder, wherein: the ceramic slurry comprises the following components in parts by weight:

26-30 parts of high-potassium sand, 8-12 parts of aluminum sand, 24-28 parts of potassium stone powder, 24-28 parts of sodium stone powder, 3-5 parts of talc mud, 8-12 parts of water-washed kaolin for glaze and 1-3 parts of calcined kaolin.

3. The method of claim 2 for making a glazed tile from solid powder, wherein: the ceramic slurry also comprises the following components in parts by weight:

0.1-0.5 part of water glass and 0.1-0.2 part of sodium tripolyphosphate.

4. The method of claim 1 for making a glazed tile from solid powder, wherein: the thickness of the green brick surface layer is 0.2 mm-1 mm.

5. The method of claim 1 for making a glazed tile from solid powder, wherein: the thickness of the green brick base layer is 3 mm-20 mm.

6. The method of claim 1 for making a glazed tile from solid powder, wherein: the particle size of the solid powder adopted in the step S1 is smaller than 12 meshes.

7. The method for manufacturing glazed tiles by using solid powder as claimed in any one of claims 1 to 6, wherein the method comprises the following steps: the fineness of the ceramic slurry is 0.2-0.4 wt% of the residue of a 250-mesh screen, and the specific gravity of the slurry is 1.7-1.85 g/cm³The flow rate is 30-45 seconds.

8. The method of claim 7 for making a glazed tile from solid powder, wherein: further comprising the steps of:

and S9, polishing the glaze.

9. The method of claim 8 for making a glazed tile from solid powder, wherein: in the step S9, four sections are adopted for polishing, and the four sections of polishing tools are respectively an elastic grinding block, a matte grinding block, a grinding friction and a polishing sheet; the fineness of the abrasive is 120-250 meshes, 260-360 meshes, 340-400 meshes and 360-600 meshes respectively.

Background

At present, in the ceramic industry, the powder preparation process which is actually applied in production mainly comprises a wet powder preparation process, a dry powder preparation process and an integrated powder preparation process.

Wet milling, i.e. spray drying milling, has been used in ceramic tile production for over forty years. The technological process of spray drying powder preparation comprises the following steps: raw material crushing → weighing and proportioning → wet ball milling → slurry sieving to remove iron → slurry homogenizing → spray drying → powder lot. The main production equipment for spray drying and pulverizing is spray drying tower and hot-air furnace, the hot-air furnace generally uses water-coal slurry (or lump coal, water gas and natural gas) as fuel, the hot-air furnace can be used for providing hot air for spray drying tower, the hot air can be used for making heat exchange with atomized slurry in the spray drying tower so as to dry the slurry whose water content is 33% -40% into powder whose water content is 6% -8%. The powder produced by the process has the advantages of good fluidity and uniformity and stable powder quality, and is widely applied to ceramic tile production enterprises. The main disadvantages of the spray drying powder process are "high energy consumption, high emission, high cost".

Dry milling: the typical dry process flow is: raw material crushing → weighing and proportioning → dry grinding (such as vertical milling) → granulating by adding water → dry optimization → powder lot. The dry method powder preparation reduces the main energy consumption equipment of the spray drying tower, so the energy consumption is low, and the economic benefit can be obviously increased. And because the energy consumption is reduced, the pollutant emission is reduced, and the ultralow emission can be realized without configuring special pollutant treatment facilities. The dry method powder preparation has no huge mud pool, the solid powder can not realize high homogenization like fluid mud, and the requirements on the quality and the stability of the raw materials are higher. And the powder prepared by dry milling has poor mixing uniformity, large dust in the production process, difficult removal of iron-containing impurities and coarse particle impurities, poor powder flowability and particle grading and the like, so that the product quality stability is poor and the product qualification rate is low, which influences the application of the dry milling process.

The main process of the integrated powder preparation process comprises the following steps: raw material crushing → weighing and proportioning → wet ball milling → sizing agent sieving and deironing → sizing agent homogenizing → filter pressing and dewatering → mud cake cutting → mud drying → granulation → optimization → qualified powder. The preparation process of the slurry of the process is basically the same as that of the slurry of the traditional process, the slurry is subjected to filter pressing and dehydration to obtain a mud cake with the water content of 20-21%, the mud cake is cut into small mud blocks and then dried by a dryer to obtain small mud blocks with the water content of about 10%, and the small mud blocks are crushed, granulated and optimized to obtain powder particles with the water content of 7-8% and the particle size meeting the requirement. Compared with the ball milling-spray drying powder preparation process and the vertical milling-dry powder preparation process, the ball milling-integrated powder preparation belongs to a wet process.

The integrated powder making process can fully utilize the afterheat of the sintering kiln, overcomes the defects of high energy consumption, high emission and high cost of the spray drying powder making process, overcomes the defects of poor mixing uniformity of ingredients, large dust in the production process and difficult removal of iron-containing impurities and coarse particle impurities of the dry powder making process, and combines certain advantages of the traditional spray drying powder making process and the dry powder making process.

The following table shows the shape comparison of the powder prepared in the 3 powder preparation processes:

	wet process for making powder	Dry milling	Integrated powder process
				Powder form	Hollow, nearly spherical	Solid, relatively irregular	Solid, relatively irregular

As can be seen from the above table, the powder mainly has two forms, i.e., hollow powder and solid powder. Compared with the spherical hollow powder with smooth and regular surface after spray granulation of wet powder preparation, the solid powder obtained by dry powder preparation and integrated powder preparation has irregular surface, rough surface, poor sphericity, higher solid strength of particles and higher requirement on press molding. This results in the inability to simply implement a dry process instead of a wet process for the powder process, requiring a subsequent change in the overall process flow.

On the glazed tile, the hollow powder obtained by wet milling has smooth surface, good fluidity and small friction among particles, when a certain pressure is applied on a blank, the hollow powder begins to move towards the stress direction, the gas among the powder is extruded by extrusion, the powder particles uniformly shrink along with the increase of the pressure to form compact accumulation, and the surface of the blank body is smooth and flat; the surface of solid powder particles obtained by dry powder preparation or integrated powder preparation is uneven and has edges and corners, the particles are irregular, the flowability is poor, the friction force among the particles is large, certain pressure is not applied to the powder, the powder particles start to move towards the stress direction, gas among the powder is extruded by extrusion, the powder particles can deform and break along with the increase of the pressure, the powder particles shrink unevenly, fine pits and protrusions are formed on the surface of a blank, the roughness is large, and the surface of the blank is not smooth and uneven. In order to solve the problem of rough surface of green bricks pressed by solid powder, the following two treatment modes exist at present:

the first is that: chinese invention patent with application number CN 2018105787454: a method for producing green brick and glazed brick by dry pulverizing features that the green brick is polished to improve its surface smoothness and smoothness, resulting in better surface smoothness and decorative effect.

Secondly, the following steps: the thickness of the ground coat is increased during glazing to cover up the defects on the surface of the green brick.

However, both of the above methods have some problems, and the first method has a major disadvantage of complicated process, and although the patent improves the surface quality of the green body, since the solid powder particles are liable to form pores inside during pressing, the green body is liable to have depressions on the surface after firing even though the surface flatness and smoothness are high. For the second method, the thickness of the ground coat is increased to increase the product cost, the price of the glaze is 2000 yuan/ton (2021 year price), the cost is higher, and secondly, the thick glaze has poor binding property due to large component difference with the green brick, and other surface defects are easy to occur.

Therefore, there is a need to develop a new process for making glazed tile from solid powder, which can improve the performance of glazed tile and reduce the cost.

Disclosure of Invention

The invention provides a method for manufacturing a glazed tile by using solid powder, aiming at solving the above factors existing in the production of the glazed tile by using the solid powder.

In order to achieve the functions, the technical scheme provided by the invention is as follows:

a method for manufacturing a glazed tile by adopting solid powder comprises the following steps:

s1, placing the solid powder into a press, and pressing under the action of a mould to form a green brick base layer;

s2, drying the green brick base layer to ensure that the water content is not more than 0.3%;

s3, uniformly spraying the ceramic slurry on the upper surface of the green brick base layer to form a green brick surface layer to obtain a green brick;

s4, drying the green brick;

s5, applying base coat on the surface of the green brick;

s6, surface decoration;

s7, applying surface glaze;

and S8, firing to obtain the glazed tile.

Preferably, the ceramic slurry comprises the following components in parts by weight:

26-30 parts of high-potassium sand, 8-12 parts of aluminum sand, 24-28 parts of potassium stone powder, 24-28 parts of sodium stone powder, 3-5 parts of talc mud, 8-12 parts of water-washed kaolin for glaze and 1-3 parts of calcined kaolin.

Preferably, the ceramic slurry further comprises the following components in parts by weight:

0.1-0.5 part of water glass and 0.1-0.2 part of sodium tripolyphosphate.

Preferably, the thickness of the adobe surface layer is 0.2 mm-1 mm.

Preferably, the thickness of the green brick base layer is 6 mm-10 mm.

Preferably, the particle size of the solid powder used in step S1 is smaller than 12 meshes.

Preferably, the fineness of the ceramic slurry is 0.2-0.4 wt% of the screen residue of a 250-mesh screen, and the specific gravity of the slurry is 1.7-1.85 g/cm³The flow rate is 30-45 seconds.

Preferably, the method for manufacturing the glazed tile further comprises the following steps:

and S9, polishing the glaze.

Preferably, in the step S9, four sections of polishing tools are used for polishing, where the four sections of polishing tools are respectively an elastic grinding block, a matte grinding block, a grinding friction block, and a polishing sheet; the fineness of the abrasive is 120-250 meshes, 260-360 meshes, 340-400 meshes and 360-600 meshes respectively.

The invention has the beneficial effects that:

1. ceramic slurry with the thickness of 0.2 mm-1 mm is uniformly sprayed on the surface of the formed green brick base layer to form a green brick surface layer, and the green brick surface layer is obtained by adopting a slurry spraying mode and is smooth and fine in surface, so that the problems of rough and uneven surface of the green brick base layer obtained by pressing solid powder are effectively solved; the surface of the glazed tile obtained after subsequent glazing, sintering and polishing has better smoothness and flatness and better decorative effect, and the color and pattern expressive force of the glazed tile are improved;

2. because the surface layer of the green brick is obtained by adopting a slurry spraying mode, the green brick base layer can be formed by adopting a coarse particle size, so that the cost of powder particles is reduced;

3. because the amount of the ceramic slurry or color paste required by the surface layer of the poured glazed tile blank is less, the ceramic slurry or color paste prepared in the same batch can meet the amount required by producing a large batch of glazed tiles, so that the glazed tile blanks produced in the same large batch can be ensured to have no color difference, and the finally obtained glazed tile finished products have no color difference;

4. the green brick surface of the glazed tile produced by the method is fine, so that the glaze amount of the ground glaze applied in the subsequent production of the glazed tile can be reduced, and the cost of the glaze material is saved.

Drawings

FIG. 1 is a flow chart of a production method of the first embodiment;

FIG. 2 is a flow chart of the production method of example two.

Detailed Description

The invention will be further elucidated with reference to the accompanying figures 1 and 2:

the first embodiment is as follows:

the powder adopted in this embodiment is solid powder obtained by dry milling or integrated milling, and the two milling processes are the prior art and will not be described herein. As shown in figure 1, the method for manufacturing the glazed tile by adopting the solid powder comprises the following steps:

s1, placing the solid powder into a press, and pressing under the action of a mould to form a green brick base layer;

s2, drying the green brick base layer to ensure that the water content is not more than 0.3%;

s3, uniformly spraying the ceramic slurry on the upper surface of the green brick base layer to form a green brick surface layer to obtain a green brick;

s4, drying the green brick to ensure that the water content is not more than 0.3%;

s5, applying base coat on the surface of the green brick;

s6, surface decoration;

s7, applying surface glaze;

and S8, firing to obtain the glazed tile.

The raw materials of the powder can adopt waste ore, tailings and low-grade raw materials, the particle size of the solid powder is smaller than 12 meshes, the water content is 7-9%, and the raw material cost and the granulation cost can be saved by selecting cheap raw materials and selecting powder with a larger particle size range. At present, when solid powder is used for pressing green bricks, powder with the grain size of more than 80 meshes and less than 30 meshes is generally used, and the purpose is to obtain better green brick surfaces in the following process. In the invention, the quality of the surface of the green brick is mainly determined by the ceramic slurry sprayed on the green brick base layer, so the particle size range of the powder forming the green brick base layer and the selection of raw materials can be properly widened, thereby reducing the manufacturing cost of the powder. In addition, the base course of the green brick accounting for more than 80 percent of the volume of the green brick is produced by adopting low-grade cheap raw materials (ceramic raw materials with low whiteness and high impurity content), so that the raw material cost of production is greatly reduced on the basis of ensuring the same appearance of the product.

Generally, the thickness of the surface layer of the green brick is 0.2 mm-1 mm, and the thickness of the base layer of the green brick is 3 mm-20 mm. In this example, the particle size of the powder used for the green brick base layer is 120 mesh to 20 mesh, the thickness is 10mm, and the thickness of the green brick surface layer is 0.8 mm.

In this embodiment, the ceramic slurry comprises the following components in parts by weight:

26-30 parts of high-potassium sand, 8-12 parts of aluminum sand, 24-28 parts of potassium stone powder, 24-28 parts of sodium stone powder, 3-5 parts of talc mud, 8-12 parts of glazed water-washed kaolin, 1-3 parts of calcined kaolin, 0.1-0.5 part of water glass and 0.1-0.2 part of sodium tripolyphosphate.

Adding an appropriate amount of water into the components for ball milling to obtain ceramic slurry with the fineness of 0.2-0.4 wt% of the residue of a 250-mesh screen and the specific gravity of 1.7-1.85 g/cm³The flow rate is 30-45 seconds. The ceramic slurry is uniformly sprayed and covered by adopting a bell jar slurry spraying methodOn the upper surface of the green brick base layer.

Because the components of the ceramic slurry and the green brick base layer are in the same formula system, the green brick surface layer sprayed with the ceramic slurry and the green brick base layer can be well combined during sintering; the different formula systems of the green brick and the glaze lead to the problem of blank glaze adaptability of the green brick and the glaze, so the glazing amount cannot be too much, and if thick base glaze is applied to cover the rough surface of the green brick to smooth the surface, the problem of cracking of a finished product and the like can be caused. The invention solves the problem of rough surface of the green brick by spraying the ceramic slurry and can reduce the amount of the ground coat.

The whiteness of the surface of the green brick has important influence on the color development of the pigment, and in the chemical components of the green brick, Fe₂O₃And TiO₂The influence on the whiteness of the blank is the largest. When Fe₂O₃And TiO₂When the content is higher, the whiteness of the blank is lower, the color development is often not pure after the pigment is introduced and sintered, and the color brightness is poor. In the present invention, the whiteness of the green brick surface is mainly determined by the green brick surface layer, so the ceramic slurry adopts low Fe₂O₃And TiO₂ The raw materials are produced, and the ceramic slurry after ball milling is subjected to iron removal treatment, so that the whiteness of the surface of the green brick can be greatly improved under the condition of not increasing much cost because the using amount of the ceramic slurry is not large.

The surface of the ceramic adobe produced by the production method is smooth and fine, so that the ceramic tile produced based on the adobe in the subsequent process has better effect.

Taking glazed tile as an example, the amount of decorative glaze, namely bottom glaze, can be reduced during production based on the green brick, the glaze of the obtained glazed tile is smooth and flat, and the glazed pattern has richer expressive force, so that the quality of the glazed tile is effectively improved. Generally, the thickness of a ground glaze of a green brick made of hollow powder obtained by wet powder making is 0.5-0.8 mm; in the invention, the thickness of the ground glaze is 0.2-0.4 mm, and the same effect can be achieved, so that the cost of the glaze is saved.

On the other hand, when the green bricks are produced by the production method, the using amount of the ceramic slurry used for slurry spraying of the surface layer of the green bricks is less, so that the ceramic slurry for slurry spraying produced by the same raw material can be used for a large batch (the production amount of a common ceramic factory is several days), and the surface color of the large batch of green bricks is determined by the ceramic slurry, so that the surface color of the large batch of green bricks is consistent, the color number is the same, and the color difference is basically avoided.

Before applying the ground coat, the surface of the green brick can be sprayed with water for wetting.

The surface decoration in step S6 is to perform inkjet printing or flat printing on the surface of the ground coat to obtain a decorative pattern.

Example two:

as shown in fig. 2, the method for manufacturing glazed tiles by using solid powder of the present invention has the same main steps as the first embodiment, and the main differences are as follows:

in order to obtain a brighter ceramic tile surface, the surface of the fired glazed tile can be polished to finally obtain the glazed tile.

In this embodiment, polishing the glaze surface adopts four-stage polishing:

a first stage: the elastic grinding block is used as a polishing machine of a polishing grinding tool, diamond abrasive is used as a polishing medium, and the fineness of the abrasive is 120-250 meshes;

and a second stage: the polishing method comprises the following steps of (1) using a matte grinding block as a polishing machine of a polishing grinding tool, using resin to bond silicon carbide and magnesium oxide grinding materials as a polishing medium, wherein the fineness of the grinding materials is 260-360 meshes;

a third stage: the polishing machine uses grinding friction as a polishing grinding tool, the bristles of the grinding friction use silicon carbide and hard plastics, and the fineness of the grinding material is 340-400 meshes;

a fourth stage: the polishing piece is used as a polishing machine of a polishing grinding tool, silicon carbide abrasive materials are embedded into fibers and obtained through compaction or bonding compaction, and the fineness of the abrasive materials is 360-600 meshes.

By the polishing, the pattern effect of the ceramic product is vivid and the luster is soft.

The method of the invention is adopted to manufacture the glazed tile, which overcomes the problems that the surface of a green brick prepared from solid powder is rough, or the surface is polished and smooth in form but is easy to form small holes on the surface after heating, so that the glaze of the glazed tile is smooth and flat, which is not inferior to the glazed tile prepared from hollow powder prepared by warm process powder preparation, thereby being beneficial to the popularization of dry process powder preparation and integrated powder preparation technology.

The above-described embodiments are merely preferred examples of the present invention, and not intended to limit the scope of the invention, so that equivalent changes or modifications in the structure, features and principles of the invention described in the claims should be included in the claims.