JPH0563216B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for granulating fine ceramic powder.

[Prior Art] In mold press molding, granulated ceramic powder is often used. Its advantage is that it has good fluidity and can be filled uniformly into the mold, resulting in a uniform molded product.

By the way, as a method for granulating ceramic powder,
Although the spray drying method is often used, there are many problems with the spray drying method as described below, and it is desired to solve these problems.

(1) Depending on the amount of binder mixed into the ceramic powder and the operating conditions of the granulation equipment, variations occur in the size, strength, and hollowness of the granules.

(2) After molding the ceramic structure, a binder removal process is required.

(3) Because the granulation process is large-scale, a large number of ceramic powders are produced.
Kg to several tens of Kg is required, making it impossible to granulate a small amount.

(4) In particular, if the granule strength is too strong, the granules will not break during molding and a molded body will not be obtained.

[Object of the Invention] The present invention was made in order to solve the problems of the prior art described above, and it is possible to easily and quickly produce ceramic granules of a uniform size with appropriate strength and no hollows into a small amount of ceramic powder. It can be granulated even with
It is an object of the present invention to provide a method for granulating fine ceramic powder, which can eliminate the need for a binder removal step in a molded article of ceramic powder granules obtained.

[Structure of the Invention] According to the present invention, the above-mentioned object is to provide a vibrator having a first stage portion with a relatively large sieve mesh, a second stage portion with a relatively small sieve mesh compared to the first stage portion, and a saucer. Using a sieve, a rolling element is placed in the first stage part together with the ceramic material to be granulated, and the vibrating sieve is vibrated at a predetermined frequency to extrude the ceramic through the sieve openings of the first stage part by the rolling element. Achieved by a method for granulating fine ceramic powder, which is characterized in that the material is classified by the sieve mesh in the second stage part, and the ceramic material present on the second stage part and on the tray is granulated by rolling with vibration. be done.

The present invention will be explained in more detail below.

The ceramic material used in the present invention is not particularly limited, and is a commonly used ceramic material that is granulated and molded to meet the above-mentioned purpose.

In the method for granulating ceramic fine powder of the present invention, ceramic granules are obtained through the steps described below. In the present invention, a multistage vibrating sieve is used during granulation, and desired ceramic granules are obtained by rolling and granulating the classified powder while performing classification. Each step will be explained with reference to FIG.

The first stage portion 3 of the vibrating sieve 1 into which the ceramic raw material 2 is introduced has a relatively rough mesh. The sieve size is preferably in the range of 20 to 40 mesh.

A required number of rolling elements such as nylon balls 4 are placed in the first stage section 3 to crush the ceramic raw material 2, which is ceramic powder or aggregates, and pass through the sieve mesh 5 of the first stage section 3 as shown at 2'. The desired particle size is forcibly extruded onto the second stage portion 6. The first stage portion is constituted by at least one sieve, and the sieve size may be the same or slightly different.

The second stage portion 6 is composed of a sieve with finer mesh than the first stage portion, and the sieve mesh is preferably in the range of 40 to 60 mesh. On the second stage portion 6, the ceramic material 2'' finer than the sieve mesh 7 falls onto the next tray 8,
The ceramic material 9, which is larger than the sieve size 7, is rolled on the second stage part 6 by vibration as shown by the arrow 10, and is granulated by rolling. The second stage portion is composed of at least one sieve, and the sieve size may be the same or slightly different.

Ceramic material 2'' that has fallen onto saucer 8 is rolled by vibration as shown by arrow 11 and is granulated by rolling. Ceramic materials 9 and 2 are granulated by rolling on second stage portion 6 and saucer 8. '' is recovered as ceramic granules.

[Operation of the Invention] Ceramic powder is placed on the first stage portion 3 of the vibrating sieve 1, and when vibration is applied, it is classified and granulated by rolling as follows.

(1) When the ceramic powder is a dry aggregate (a) The ceramic powder (aggregate) is crushed by the rolling of the rolling elements 4.

(b) The pulverized ceramic powder gets stuck in the sieve mesh 5 (for example, 32 mesh) of the first stage portion 3, but is forcibly pushed out by the weight of the rolling elements.
It becomes as small as the opening of the mesh and falls onto the next second stage portion 6.

(c) Further, on the second stage part 6, particles larger than the sieve mesh 7 (for example, 60 mesh) remain and are granulated by rolling, and particles smaller than the sieve mesh and pulverized are transferred to the next receiving tray 8. It falls to the top where it is granulated by rolling.

(d) Granules granulated on the second stage portion 6 and tray 8 are obtained as ceramic granules.

(2) When the ceramic powder is in powder form (e) The rolling elements 4 prevent it from gathering in a snowball-like manner on the first stage part (for example, 32 meshes) due to vibration, and then the process described in (1) above is performed. b) It is rolled and granulated in the same manner as the following process.

[Effects of the Invention] The above-mentioned classification and rolling granulation method of the present invention provides many advantages as described below compared to the conventional spray drying granulation method.

(1) Since rolling granulation is performed after classification in the first and second stages of the vibrating sieve, there is little variation in the size and strength of the granulated ceramic granules, and the problem of hollow granules is avoided. will also become smaller.

(2) Ceramic and binder are not used together, so
No binder removal process is required after molding.

(3) The granulation device can be made small as shown in the following examples, and can easily granulate a small amount.

(4) As mentioned in (1), the granule strength is appropriately adjusted, so when molded using this, a good molded product can be obtained.

[Example] Next, the present invention will be specifically explained with reference to an example.

The vibrating sieve consists of an upper stage, a lower stage, and a saucer as shown in Figure 1.The upper stage is a 32 mesh sieve, the lower stage is a 60 mesh sieve, and the sieve diameter is approximately 20 cm.
I used the one from

The ceramic materials used were aggregates (5 to 10 μm) and powders (approximately 1 μm) that had been crushed using a solvent in the previous step and dried. Put 50-100g of ceramic into the upper part of the vibrating sieve, then put about 10 nylon balls with a diameter of 15mm, and put the lid on.
The material was sieved for about 5 minutes at a vibration frequency of 290 rpm. The agglomerates and powders were also classified and granulated by rolling as explained in the operation of the present invention to obtain ceramic granules with an average particle size of 200 to 500 μm.

When the granules on the lower stage and on the saucer were mixed and used for mold molding, a uniform molded product with good fluidity was obtained.

Furthermore, as the vibrating sieve, in addition to the one shown in FIG. 1, a rotating vibrating type that utilizes centrifugal force and has a first sieve part 3, a second sieve part 6, and a saucer 8 concentrically from the inside is used. When granulation was carried out in the same manner as above, similar results were obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagrammatic cross-sectional view for explaining the ceramic fine powder granulation method of the present invention. Explanation of symbols, 1... vibrating sieve, 2, 2', 2''...
Ceramic material, 3... First stage part, 4... Rolling element, 5, 7... Screen mesh, 6... Second stage part, 8...
Saucer, 9...Ceramic granules, 10, 11...
Rolling direction.

Claims (1)

[Claims] 1. Granules should be granulated in the first stage part using a vibrating sieve having a first stage part with a relatively large sieve mesh, a second stage part with a relatively small sieve mesh compared to this first stage part, and a saucer. By putting a rolling element together with the ceramic material and vibrating the vibrating sieve at a predetermined frequency, the ceramic material pushed out by the rolling element through the sieve openings in the first stage part is classified by the sieving openings in the second stage part. A method for granulating fine ceramic powder, characterized in that the ceramic material present on the two-stage portion and on the saucer is granulated by rolling by vibration.