JPH07116533A - Ball mill and treatment of ceramic powder - Google Patents

Abstract

PURPOSE:To prevent the formation of the groove caused by the wear due to a ball stone on the inside surface of a peripheral wall even if a ball mill is used for long time. CONSTITUTION:A guide surface 16 is formed so that the ball stone comes not in contact with the inside surface of the peripheral wall 13 and an inside surface of an edge wall 14 simultaneously at the area where the inside surface of the peripheral wall 13 and the inside surface of the edge wall 14 cross each other. In this way, the ball stone does not stay at a prescribed position, and the formation of the groove caused by the wear due to the ball stone is prevented, and the mixing and/or grinding treatment of the material to be treated is executed in uniform quality over a long period of time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball mill and a method for treating ceramic powder using the ball mill,
In particular, the present invention relates to an improvement for extending the life of a pot provided in a ball mill.

[0002]

2. Description of the Related Art Usually, a ceramic green sheet is prepared for manufacturing a ceramic electronic component, and a ceramic slurry is prepared for obtaining a ceramic green sheet. In the production of the ceramic slurry, for example, first, a crushing step is required to make the sintered ceramic material into a fine powder,
Next, a step of uniformly mixing the ceramic powder with the binder is required. The crushing process and the mixing process as described above are performed using, for example, a ball mill.

FIG. 4 is a sectional view showing the outline of such a ball mill. The ball mill includes a drum-shaped pot 1. The pot 1 has a central axis 2 oriented horizontally.
Which are rotated around as shown by arrow 3 and are located at both ends of the peripheral wall 5 so as to close the peripheral wall 5 and the peripheral wall 5 which are positioned so as to form the space 4 around the central axis 2. Has an end wall 6 which is Such a pot 1 is made of resin such as polyamide resin.

In the space 4 inside the pot 1, a material to be processed (not shown) is accommodated together with a plurality of cobblestones 7.
The cobblestone 7 is made of, for example, ceramic and has a spherical shape. When crushing the sintered ceramic material, such a ceramic material is accommodated in the pot 1 together with a liquid such as water. Further, when the ceramic slurry is to be obtained, the ceramic powder is stored in the pot 1 together with the binder.

While the pot 1 rotates, a plurality of boulders 7
Move randomly in the space 4, which facilitates the grinding or mixing as described above.

[0006]

In order to sufficiently perform the above-mentioned pulverization or mixing, it is important that the plurality of cobblestones 7 make a random movement while the pot 1 rotates. However, a phenomenon in which a plurality of cobblestones 7 are sequentially aligned along the inner surface of the peripheral wall 5 while keeping the particular one in contact with the inner surface of the end wall 6 and such an aligned state is maintained. Often occurs. As a result, when the ball mill is operated for a long time such as 2000 hours, the cobblestone 7 may wear the peripheral wall 5 and form the groove 8 on the inner surface of the peripheral wall 5, as shown in FIG.
The groove 8 may reach a depth corresponding to the radius of the boulder 7.

The groove 8 as described above prevents random movement of the cobblestone 7. As a result, it becomes difficult to obtain sufficient homogeneity in the grinding and mixing steps. For example, when trying to obtain a ceramic slurry, the dispersibility of the ceramic powder in the ceramic slurry decreases.

Therefore, an object of the present invention is to provide a ball mill which, even when used for a long period of time, prevents abrasion at a specific place on the inner surface of the peripheral wall and thereby prolongs the life of the ball mill. It is an object of the present invention to provide a method for treating ceramic powder using such a ball mill.

[0009]

SUMMARY OF THE INVENTION The present invention is for rotating about a central axis oriented horizontally, and a peripheral wall positioned to form a space around said central axis and said peripheral wall. A pot having end walls respectively positioned at both ends of the peripheral wall so as to close the space is provided, and a material to be treated is contained in the space in the pot together with a plurality of boulders, and mixed and / or crushed. To be processed, which is directed to a ball mill, in order to solve the above-mentioned technical problem, in the region where the inner surface of the peripheral wall and the inner surface of the end wall intersect, each of the cobblestones and the inner surface of the peripheral wall and It is characterized in that a guide surface is formed so as not to contact the inner surface of the end wall at the same time.

The present invention also provides a method for treating ceramic powder using the above-mentioned ball mill, and in this treating method, the above-mentioned material to be treated contains ceramic powder. That is, in this ceramic powder processing method, the ceramic powder is crushed or mixed.

[0011]

In the ball mill according to the present invention, the guide surface formed in the region where the inner surface of the peripheral wall and the inner surface of the end wall intersect with each other causes a specific cobblestone to contact the inner surface of the peripheral wall and the inner surface of the end wall at the same time and stabilize. The boulders that come into contact with the inner surface of the peripheral wall frequently change their positions.

[0012]

Therefore, according to the ball mill of the present invention, it is possible to prevent a specific portion of the inner surface of the peripheral wall from being worn by the boulders and forming a groove on the inner surface. Therefore, even if the ball mill is used for a long time, the random movement of the cobblestones is guaranteed, and the uniformity of the mixing and / or pulverizing process by the ball mill can be maintained for a long time.
As a result, the life of the ball mill can be extended.

According to the method for treating ceramic powder according to the present invention, the ceramic powder can be uniformly mixed and / or pulverized even after the ball mill has been used for a long time. Therefore, it is possible to obtain the ceramic powder and the ceramic slurry with stable quality.

[0014]

FIG. 1 is an enlarged sectional view showing a part of a pot 11 provided in a ball mill according to an embodiment of the present invention. Like the pot 1 described above, the pot 11 is made of a resin such as a polyamide resin, and is rotated around a central axis line oriented in the horizontal direction. The pot 11 has a peripheral wall 13 positioned so as to form a space 12 around the central axis and an end wall 14 positioned at both ends of the peripheral wall 13 so as to close the space 12.
(Only one end wall 14 is shown). A plurality of cobblestones 15 are housed in the space 12 inside the pot 11. Together with these cobblestones 15, the material to be treated (not shown) is housed in the space 12, whereby the material is subjected to a mixing and / or grinding treatment. For example, the sintered ceramic material is contained in the pot 11 together with water or an organic solvent, and is thereby made into a fine powder. Further, when the ceramic powder is stored in the pot 11 together with the binder, a uniform ceramic slurry is obtained.

In this embodiment, the inner surface of the peripheral wall 13 and the inner wall 1 are
A guide surface 16 having a rounded surface is formed in a region where the inner surface of 4 intersects. As can be seen from the state of the cobblestone 15 indicated by the alternate long and short dash line, this guide surface 16 has the peripheral wall 13
15 and the inner surface of the end wall 14 at the same time so that the boulders 15 do not come into contact with each other. In order to enable such an action, it is sufficient that the radius R of the rounded surface that provides the guide surface 16 and the diameter d of the cobblestone 15 satisfy the relationship of R / d> 0.5. Further, when the relationship of R / d ≧ 1 is established, the effect of preventing the cobblestone 15 from remaining at a certain position can be more exerted.

FIG. 2 shows the wear rate and life when the R / d ratio is changed. The wear rate is
The ratio of t / T shown in FIG. 5 when the ball mill was used for 2000 hours is shown.

As can be seen from FIG. 2, the R / d ratio is 0.5.
When it exceeds, the effect of decreasing the wear rate (t / T) and prolonging the life is exhibited. In particular, when the R / d ratio is 1 or more, it is more effective in reducing the wear rate and extending the life.

In the above-described embodiment, the guide surface 16 has a rounded surface. However, such a guide surface 16 works so that the cobbles do not contact the inner surface of the peripheral wall and the inner surface of the end wall at the same time. In that case, in addition to forming the protrusion, it may be modified in any manner. In Figure 3,
A modification of the guide surface is shown.

Referring to FIG. 3, guide surface 16a is formed with a linearly extending gradient. Even with such a guide surface 16a, as can be seen from the boulder 15 indicated by the alternate long and short dash line, the boulder 15 is formed on the inner surface of the peripheral wall 13 and the end wall 14.
Simultaneous contact with the inner surface of the can be prohibited.

Furthermore, in the above embodiment, the resin is used as the pot, but the pot is not limited to this, and may be made of metal, ceramic, or other material, and the inner wall of the pot may be made of resin. What formed the film may be used.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view showing a part of a pot 11 provided in a ball mill according to an embodiment of the present invention.

FIG. 2 is a graph showing each of the wear rate and the life obtained when the R / d ratio is changed in the example shown in FIG.

FIG. 3 is a sectional view corresponding to FIG. 1, showing a pot provided in a ball mill according to another embodiment of the present invention.

FIG. 4 is a sectional view schematically showing a pot provided in a conventional ball mill.

FIG. 5 is an enlarged sectional view showing a part of the pot 1 for explaining the problem to be solved by the present invention.

[Explanation of symbols]

 11 pot 12 space 13 peripheral wall 14 end wall 15 boulders 16, 16a guide surface

Claims (2)

[Claims] 1. A peripheral wall that is rotated about a central axis that is oriented in the horizontal direction and that is positioned so as to form a space around the central axis and that of the peripheral wall that closes the space. A ball mill comprising a pot having end walls respectively positioned at both ends, wherein a material to be treated is contained in the space in the pot together with a plurality of cobblestones, and is mixed and / or pulverized, In the area where the inner surface of the peripheral wall and the inner surface of the end wall intersect,
A ball mill, characterized in that a guide surface is formed to prevent each of the cobblestones from simultaneously contacting the inner surface of the peripheral wall and the inner surface of the end wall. 2. A method of treating ceramic powder using the ball mill according to claim 1, wherein the material to be treated according to claim 1 comprises ceramic powder.