JP2002037671A - Method for forming ceramic and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the method for forming a ceramic, in which the forming body to be formed from slurry is irradiated with microwaves, associated water existing in the surface of raw material grains is removed, and the forming body that is dense and thick-walled can be produced, and provide a device for the method. SOLUTION: In this method for forming a ceramic, slurry 7 is prepared by allowing ceramic raw material powder to contain moisture and have fluidity. When the forming body is formed from slurry 7 and dried, a microwave generating device 4 is activated and the forming body is irradiated with microwaves, thus moisture 9 in the body is removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic molding method and apparatus for removing water from a slurry using a microwave when molding a ceramic constituting a filter.

[0002]

2. Description of the Related Art Conventionally, as a method of forming a ceramic molded body, a method of absorbing water in a gypsum mold using a slurry in which water and powder are blended, and solidifying the slurry, or a method of forming a slurry using a binder such as agar. After molding to produce a molded body,
There is known a method of drying and solidifying the compact.

[0003] Japanese Patent Application Laid-Open No. 7-215768 discloses a silicon nitride sintered body and a method for producing the same. This silicon nitride sintered body uses inexpensive Si powder,
With addition of Si ₃ N ₄ powder to the Si powder, Y ₂ O
₃ , an auxiliary agent of Al ₂ O ₃ is added, and the mixing ratio of the auxiliary agent is set to 6.6 to 12% with respect to the total weight, thereby improving the mechanical strength.

[0004]

However, in the conventional method for forming ceramics, it is difficult to remove water from the slurry of the formed body, especially when the formed body is thick. Bound water adhered to the surface of the constituent particles cannot be removed, and it is difficult to produce a thick molded body, and there is a problem that a good molded body cannot be obtained.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to use a microwave for drying a slurry or a slurry, which is different from the external heating of the compact. , To remove moisture from the inside, especially to enable the removal of water bound to the particle surface of the raw material powder in the slurry, and to properly dry the inside even if the molded body is thick It is an object of the present invention to provide a ceramic molding method and a ceramic molding apparatus capable of efficiently forming a thick molded body.

[0006]

Means for Solving the Problems A method of forming a ceramic for achieving the above object has the following features.

[0007] 1) A ceramic forming method comprising the steps of making a slurry by adding water to ceramic raw material powder to impart fluidity, forming a compact from the slurry, and drying the compact. In the method,
In the step of drying the compact, the moisture is removed from the compact using a microwave.

[0008] 2) In the above-described method of forming a ceramic, in the step of forming a compact from the slurry, when the slurry is formed into the compact by casting using a porous mold, the porous mold is used. In addition, the moisture contained in the inlaid portion of the slurry inlaid on the porous mold is to remove the moisture using a microwave.

3) In the method of forming a ceramic, the ceramic raw material powder contains the water in the step of making the slurry by adding the water to the ceramic raw material powder to give fluidity. After adding a binder made of a substance having a property of expanding and contracting with drying, the slurry was molded using a dense mold to produce a molded body, and then cast into the dense mold. The method is characterized in that the water contained in the slurry is removed by using a microwave, and the compact is shrunk and densified.

[0010] Further, in the above-mentioned method for molding ceramics, the swellable binder is agar.

A ceramic forming apparatus for realizing the above-described method for forming a ceramic is constituted as follows.

5) a porous mold for absorbing water from the slurry, a depressurized container disposed in close contact with a lower portion of the porous mold, a leak valve and an exhaust vacuum pump provided in the depressurized container, And a microwave generator for generating microwaves installed in the decompression container.

According to the method and the apparatus for forming ceramics having the above-mentioned structure, the bound water adhering to the surface of the particles constituting the formed body can be reliably removed from the slurry by the action of the microwave, and the dense thick wall free from defects can be obtained. Can be produced.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2,
An embodiment of a method and an apparatus for forming ceramics according to the present invention will be described.

FIG. 1 is a schematic explanatory view showing a ceramic molding apparatus according to one embodiment of the present invention, showing a state in which a slurry is filled in a molding die. FIG. 2 is a diagram showing the slurry filled in the molding apparatus in FIG. FIG. 4 is a schematic explanatory view showing a state in which a granular material has arrived.

The method for forming a ceramic according to the present invention comprises:
A process of forming a slurry 7 by adding fluidity to the ceramic raw material powder to impart fluidity, a process of forming a compact from the slurry 7, and a process of drying the compact;
The step of drying the molded body is characterized in that moisture is removed from the molded body using a microwave.

In the step of producing a molded body from the slurry 7, the raw material particles 8 in the slurry 7 are sequentially deposited on a molding die 10 to form an inlaid portion 12, thereby producing a molded body. The molding die 10 includes a dense mold 1 such as a resin material and a porous mold 2 such as a gypsum mold. In this embodiment, a predetermined amount of silicon powder is used as the ceramic raw material powder, and the slurry 7 is prepared by mixing water 9 with silicon powder, a sintering aid, and a mating material.

This method of forming a ceramic is particularly effective when the slurry 7 is formed into a molded article by casting using the porous mold 2 in the step of producing the molded article from the slurry 7. The water 9 contained in the inlaid portion 12 of the slurry 7 inlaid on the mold 2 is removed by using the microwave generated by the microwave generator 4. Generally, water 9
Although it is composed of bound water and free water surrounding the raw material particles 8, the bound water can also be removed by the action of the microwave, so that a molded body composed of the densely attached portion 12 of the raw material particles 8 is formed.

Next, an apparatus for forming ceramics according to an embodiment of the present invention will be described.

The ceramic molding apparatus comprises a porous mold 2 for absorbing water 9 from the slurry 7 and a porous mold 2 for absorbing the water 9.
, A leak valve 5 and an evacuation vacuum pump 6 provided in the
And a microwave generating decompression chamber 13 in the decompression container 3.
And a microwave generating device 4 for generating microwaves provided in the system.

In this embodiment, the porous mold 2 is a vacuum container 3
A dense plate 26 is arranged on the outer periphery of the porous mold 2 in order to prevent gas from flowing into the decompression container 3 from the outside. Although not shown, the dense plate 26 is unnecessary in the case of a structure in which the porous mold 2 is placed on the upper inner wall at the edge of the decompression container 3.

Then, by opening the leak valve 5 provided in the decompression container 3, the microwave generation decompression chamber 13 is opened.
The water vapor and the like generated inside is discharged to the outside through the leak port 14. In addition, the operation of the evacuation vacuum pump 6
The gas is discharged from the microwave generating decompression chamber 13 to the exhaust port 1
1 is exhausted through the pressure reducing chamber 1 for microwave generation.
3 becomes a negative pressure, whereby the water 9 of the slurry 7 is absorbed through the porous mold 2, and the inlay of the slurry 7 on the mold 10 proceeds smoothly.

Using the ceramic molding apparatus shown in FIGS. 1 and 2, a ceramic molded body was produced as follows.

A slurry 7 was prepared by mixing a predetermined amount of silicon powder, a sintering aid and raw material particles 8 composed of a mating material with water 9. A slurry 7 is placed in a mold 10 consisting of a dense mold 1 forming a side periphery and a gypsum-type porous mold 2 forming a bottom.
Fill. Next, the raw material particles 8 in the slurry 7 are deposited on the porous mold 2 to form a deposit 12, and the microwave generator installed in the depressurized container 3 below the porous mold 2, that is, the gypsum mold 2. 4 was operated to extract the water 9 from the inlaid portion 12, and the evacuation vacuum pump 6, that is, the decompression pump, was operated to discharge water vapor of the water 9 to the outside through the exhaust port 11.

In a usual heating method during molding, the raw material particles 8
Although it was difficult to remove the bound water adhered to the surface, the bound water was continuously extracted and discharged by the action of the microwave, so that a compact having a meat pressure could be produced.

Next, another embodiment of the method and apparatus for forming ceramics according to the present invention will be described with reference to FIGS.

FIG. 3 is a schematic explanatory view showing a state in which a slurry is filled in a molding die in another embodiment of the ceramic molding apparatus according to the present invention, and FIG. FIG. 3 is a schematic explanatory view showing a state in which the particles are densified by drying shrinkage.

The method of forming the ceramics is basically constituted by the same steps as those shown in FIGS. 1 and 2, except that it comprises a dense mold 20 as a mold and a swelling Is contained. That is, the raw material powder of the ceramic raw material powder, that is, the raw material particles 18
To the slurry 17 by adding water 19 to the fluid to impart fluidity.
In the process of making the ceramic raw material powder 18,
9, a binder 24 made of a substance having a property of expanding and contracting with drying is added to the dense mold 20.
The slurry 17 is formed by using
After the production of the microwave generator 1, the water 19 contained in the slurry 17 cast in the dense mold 20 is removed from the microwave generator 1.
5 is removed by using microwaves generated by operating 5, and the compact 21 is shrunk and densified.
As the swellable bonding material 24, for example, agar can be used.

Next, another embodiment of the ceramic forming apparatus according to the present invention will be described.

Since this ceramic molding apparatus uses the dense mold 20 as a molding die, there is no need to provide a decompression chamber or the like below the dense mold 20. Accordingly, the molding apparatus includes a dense mold 20 for filling the slurry 17 and a moisture 19 from the dense mold 20 to evaporate the raw material particles 18 into the dense mold 2.
A microwave generating container 16 for forming a microwave generating chamber 22 for generating microwaves is provided around the dense mold 20 so that the microwave is formed in the inside of the mold. Dense type 2
Numeral 0 supports the microwave generator 16 in the microwave generation chamber 22 while supporting the microwave generator 15 in the microwave generation chamber 16. The microwave generator 15 is provided around the dense mold 20. Further, the steam generated from the slurry 17 is configured to be evaporated and discharged from an opening 25 formed in an upper portion of the microwave generating chamber 22.

Using the ceramic molding apparatus shown in FIGS. 3 and 4, a ceramic molded body was produced as follows.

A slurry 17 was prepared by mixing a predetermined amount of silicon powder, a sintering aid and a raw material particle 18 composed of a mating material with a binder 24 composed of agar and water 19. The slurry 17 was cast into a mold made of a dense mold 20 made of a resin material to produce a plate-shaped molded body 21 having a ceramic molded body having a thickness of 50 mm. After the molding of the molded body 21, the microwave generator 15 was operated, and the molded body 21 was dried by applying a microwave. The molded body 21 was dried by the action of the microwave, shrunk and densified accordingly, and finally, a molded body of a thick product having a thickness of 30 mm and having no defect was obtained. .

The ceramic molding apparatus according to the present invention comprises:
As shown in FIGS. 1 and 2 and FIGS. 3 and 4, the structure is such that microwaves act on the slurries 7 and 17, and when a ceramic molded body is manufactured, a conventional method uses While the thickness limit is about 10 mm, in the present invention, the slurry 7, 17 is microwaved and dried, so that the bound water adhering to the raw material particles 8, 18 can be removed satisfactorily, and defects can be reduced. A compact having a thickness of 30 mm was obtained.

[0034]

The method and apparatus for molding ceramics according to the present invention are constructed as described above, so that the action of the microwave allows not only the free water out of the water but also the surface of the raw material particles of the ceramics. Bound water adhered to the surface can be effectively removed, and a thick molded product having no defect can be easily obtained.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a state in which a slurry is filled in a molding die in a ceramic molding apparatus according to one embodiment of the present invention.

FIG. 2 is a schematic explanatory view showing a state in which a granular material is deposited from the slurry filled in the molding apparatus of FIG.

FIG. 3 is a schematic explanatory view showing a state in which a slurry is filled in a forming die in a ceramic forming apparatus according to another embodiment of the present invention.

FIG. 4 is a schematic explanatory view showing a state in which a slurry filled in the molding apparatus of FIG. 3 is dried and shrunk and densified.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dense type 2 Porous type 3 Decompression container 4,15 Microwave generator 5 Leak valve 6 Evacuation vacuum pump 7,17 Slurry 8,18 Particles 9,19 Water 10 Mold 11 Exhaust port 12 Filling part 13 Microwave Generation decompression chamber 14 Leak port 16 Microwave generation container 20 Mold (dense type) 21 Inlaid part (molded body) 22 Microwave generation chamber 24 Binding material 25 Opening

Claims (5)

[Claims] 1. A method of forming a ceramic, comprising the steps of: adding water to ceramic raw material powder to impart fluidity to form a slurry; forming a molded body from the slurry; and drying the molded body. In the method, the step of drying the molded body includes removing the moisture from the molded body using a microwave. 2. In the step of producing the molded body from the slurry, when the slurry is produced in the molded body by casting using a porous mold, the porous mold and the porous mold are filled. 2. The method according to claim 1, wherein the moisture contained in the inlaid portion of the slurry is removed by using the microwave. 3. 3. In the step of making the slurry by adding the water to the ceramic raw material powder to impart fluidity, the ceramic raw material powder expands by containing the water and contracts with drying. After adding a binder made of a substance having properties, forming the compact by molding the slurry using a dense mold, the water contained in the slurry cast into the dense mold is microwaved. 2. The method of forming a ceramic according to claim 1, wherein the molded body is densified by shrinking the formed body. 4. The method according to claim 3, wherein the swellable binder is agar. 5. A porous mold for absorbing water from a slurry, a depressurized container disposed in close contact with a lower part of the porous mold, a leak valve and an exhaust vacuum pump provided in the depressurized container, An apparatus for forming ceramics, comprising: a microwave generating source provided in a decompression container for generating microwaves.