JP2000000481A - Pulverizer for ceramic particles and method of pulverizing same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a device and method for coarsely pulverizing ceramic particles. SOLUTION: In an agitation tank 2, an agitation body 3 that a lot of blade plates 11 are laminated is installed and is driven at low speed of 1-6 m/s peripheral velocity. The blade plates 11 each have a lot of blade parts on the outer periphery thereof and are fitted to a driving shaft 12 with the phases of the blade parts being shifted from each other, thereby forming a spiral blade 17. Dispersing mediums like beads are sealed in the tank 2, and slurry of ceramic particles is fed from a feed port 5, and the spiral blade 17 gives rotational force and thrust as shown by arrows 18, 19 to a mixed body M of the dispersing mediums and the slurry. A screw 20 is provided as the need arises to limit throughput of the slurry. A separation part 4 is installed in the upper part wherein a ratio of the dispersing mediums is small to return the mediums to the tank by centrifugal force to separate the slurry.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an apparatus and a grinding method for continuously grinding ceramic particles.

[0002]

2. Description of the Related Art An apparatus of this type is disclosed, for example, in Japanese Unexamined Patent Publication No.
The devices described in JP-A-4-43337 and JP-A-4-61635 are known, and a stirrer provided with a blade or a convex portion on the outer periphery is provided in a stirring tank by using these devices. A bead-shaped dispersion medium is accommodated, and a slurry in which ceramic particles as a material to be treated are mixed with a liquid such as water or an organic solvent is supplied to a stirring tank, and the slurry is stirred with the dispersion medium to pulverize the ceramic particles. Thereafter, a pulverization method of separating the dispersion medium in a medium separation unit and discharging the processed slurry is used.

[0003] In the conventional pulverizing apparatus and pulverizing method,
The peripheral speed of the stirrer is set to about 10 m / s, and it operates so as to pulverize the ceramic particles extremely finely. In FIG. 4 (A), the particles indicated by a on the left are ceramic particles formed by spray-drying a solution of a plurality of types of materials and then calcining the particles. And a single particle a has a diameter d of 0.1.
The size is 1 to several μm.

[0004] However, in order to pulverize the powder into such fine powder b, it is necessary to apply a high torque to the agitator to operate it for a long time. Moreover, as shown in FIG.
In the case of having a multilayer structure in which the surface of the particle a is coated with another component c, or in the case of having a gradient structure having a different composition ratio from the center of the particle a toward the surface of the particle a, the fine powder b contains components Many fine powders not coated with c and fine powders having different composition ratios are mixed, and uniform ceramic particles cannot be obtained.

Further, if a gap separator driven by a stirrer is used in the medium separation section, the dispersion medium is caught in the gap, and there is a disadvantage that the resistance to rotation of the stirrer increases.

[0006]

An object of the present invention is to crush and remove ceramic particles having a multilayer structure or a gradient structure formed by calcination with little energy while maintaining the structure of the particles. Make it an issue.

[0007]

Means for Solving the Problems The first means among the means for solving the above-mentioned problems is, as described in claim 1, beads in a stirring tank having a stirring body having a blade portion on the outer periphery. In a ceramic particle pulverizing apparatus for accommodating a dispersion medium having a shape and stirring while continuously supplying a slurry of ceramic particles to the stirring tank and discharging the slurry after stirring from the medium separation unit, the blades of the stirring body The spiral is provided in the range of two-thirds or more of the inner diameter of the stirring tank, and a spiral is formed at the blades from both ends in the longitudinal direction of the stirring body to propel the slurry and the dispersing medium. A medium separation unit of a centrifugal separation type, and a drive source for the blade unit and a drive source for the medium separation unit are separately provided.

According to this means, excessive fine powder is prevented from being generated in the ceramic particles having the multilayer structure or the inclined structure. Also, the dispersion medium having a larger diameter than the ceramic particles in the slurry tends to sink downward, and the amount of the dispersion medium entering the medium separation unit located at the top of the stirring tank is reduced, and the separation efficiency is improved.

The second means is characterized in that, in the first aspect, the front surface in the rotation direction of the blade portion is a surface whose outer peripheral side is recessed from the center side.
According to this means, the impact acting on the ceramic particles and the dispersion medium is reduced, and excessive pulverization is prevented.

According to a third aspect of the present invention, in the first or second aspect, a plurality of blade plates provided with blades on the outer periphery are fixed to the drive shaft with their phases shifted, so that the blade portion is formed. Characterized by forming a twist of According to this means, the blades are attached to the drive shaft and shifted in phase, and the blades are twisted by overlapping and fixing the blades to the drive shaft.

According to a fourth aspect of the present invention, as set forth in claim 4, a bead-shaped dispersion medium is accommodated in a stirring tank provided with a stirring member having blades on the outer periphery, and a slurry of ceramic particles is placed in the stirring tank. In the method of pulverizing ceramic particles, in which the stirring is performed while continuously supplying the slurry and the slurry after the stirring is discharged from the medium separating unit, the blades of the stirrer are mixed with the contents of the stirring tank according to the contents of the stirring tank.
A spiral body for driving the slurry and the dispersion medium is formed in the center from both ends in the longitudinal direction of the stirring body by the blades, and a centrifugal separation type medium separation section is provided above the center line of the stirring body. Is provided, and the peripheral speed of the blade portion is set to 1 to 6 m / s,
The peripheral speed of the medium separation unit is set to be higher than the peripheral speed of the blade unit.

According to this method, excessive fine powder is prevented from being generated in ceramic particles having a multilayer structure or a gradient structure, and can be pulverized and taken out with little energy.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment,
In the figure, 1 is a crusher, 2 is a stirrer, 3 is a stirrer, and 4 is a centrifugal medium separation unit. The stirring tank 2 is pre-enclosed with a dispersion medium composed of beads such as glass or ceramic for transmitting the pressure or impact force of the blades to the ceramic particles via media, and the beads have a diameter of 0.1 to 0.1 mm. About 2.0 mm, about 60% of the volume of the stirring layer 2 is used. The stirring tank 2 is provided with a supply port 5 at one end, and a slurry in which the ceramic particles a and water are mixed in substantially equal amounts is pumped by a pump.

The medium separation section 4 is provided at an upper portion of the tank 2 opposite to the supply port 5, and a case 6 opening downward is connected to the stirring tank 2, and is connected to a rotating shaft 7 supported by the case 6. The output of the centrifuge 8 and the motor 9 is fixed. The centrifuge 8 has one or more flow paths 8a penetrating in the diameter direction.
A T-shaped flow path 7 a is provided on the rotating shaft 7, and communicates the flow path 8 a with the outlet 10.

The stirrer 3 is formed by stacking a number of blades 11 shown in FIG. 2 with their phases shifted as shown in FIG.
2 fixed. The blade plate 11 is provided with a blade portion 13 and a valley portion 14 on the outer periphery, a square hole 15 at the center, and a square shaft portion 12 a provided on the drive shaft 12.
And driven by the motor 16 in the direction of arrow A. The blade portion 13 is provided in a range of not less than ／ of the inner diameter of the stirring tank 1, and has a receding angle α on the front surface 13 a in the rotation direction,
The rear surface 13b extends substantially in the radial direction.

Since nine sets of the blades 13 or the valleys 14 in FIG. 2 are provided, one pitch is 40 °, and when the two blades 11 are shifted by 90 ° and fitted to the square shaft 12a, 2
A displacement of a sum of 80 ° and 10 ° corresponding to the pitch results in a displacement of 10 ° between the blades 13 and 13 or between the valleys 14 and 14 of two adjacent blades 11.

Therefore, when each blade plate 11 is shifted by 90 ° and fitted to the square shaft portion 12a, the blade portions 13 are arranged in a stepped spiral shape as a whole, and a spiral body 17 is formed. The pitch angle of the blade portion 13 and the shape of the square hole 15 can be appropriately determined without being limited to those described above.
Spline fitting can be used instead of fitting the square hole and the square shaft.

In FIG. 1, the spiral body 17 formed by the blade section 13 is formed symmetrically, and the mixture of the slurry and the dispersion medium in the stirring tank 2 is rotated by rotating the drive shaft 12 in the direction of arrow A. Receives thrusts in the directions of arrows 18 and 19 while being pressed in the circumferential direction by the blade portion 13, and acts so as to press against each other at the center.

An axial pump type screw 20 is fixed to the drive shaft 12 on the side of the medium separation section 4 and driven at the same speed as the stirring body 3 to feed the mixture M into the supply port 5 as shown by an arrow 21. The thrust in the direction of pushing back is generated. However, the pressure of the slurry entering from the supply port 5 is set so as to overcome the thrust generated by the stirring body 3 and the screw 20. The screw 20 can be omitted.

When the apparatus 1 is operated, the mixture M of the slurry and the dispersion medium in the stirring tank 2 moves in the axial direction while rotating by the rotation of the stirring body 3, but the dispersion medium in the mixture M has a large diameter. It is easy to sink down due to its large mass,
In addition, a large centrifugal force is easily generated. The present invention focuses on this point. The medium separator 4 is provided above the stirring tank 2 to reduce the rate at which the separation medium flows into the separator 4, and the peripheral speed of the centrifuge 8 is reduced by the stirring speed of the stirring body 3. Alternatively, the dispersion medium is pushed back out of the separator 4 by increasing the peripheral speed of the screw 20, and the separation efficiency of the slurry is improved by these means.

Further, by making the front surface 13a of the blade portion 13 have a receding angle and by driving the blade portion 13 at a peripheral speed of about 1 to 6 m / s, which is lower than that of the conventional device, the ceramic particles a The applied impact force was reduced to prevent excessive pulverization.

In the above-described embodiment, the blade plate 11 has a large number of blade portions 13 and valley portions 14, and the spiral 17 is formed by shifting the phases thereof.
Can be used. The slat 1
1a is a disk having a circular contour, and a square hole 15 is provided at an eccentric position shifted from the center of the disk. A spiral body is formed by displacing the wing plate 11a by 90 ° and fitting it to the square shaft portion 12a.

Next, a second embodiment of the present invention will be described. In FIG. 5, 1 is a crusher, 2 is its stirring tank,
Reference numeral 3 denotes a stirrer, 4 denotes a centrifugal medium separation unit, and other components common to those in the apparatus in FIG.

A major difference between the second embodiment and the first embodiment is the flow direction of the slurry with respect to the rotating shaft 12 of the stirring body 3. The point is that the supply port 5 is provided at the proximal end. At the end of the stirring tank 2 on the motor 16 side,
A partition wall 23 having a large-diameter inflow chamber 22 formed on the inner peripheral side and an end wall 24 are fixed, and the drive shaft 12 is provided with a stepped sleeve 2.
5 is fitted, and the inflow chamber 22 is
A larger diameter flange 26 is fixed, and a gap 27 is formed between the flange 26 and the end wall 23. The inflow pipe 5 is connected to the inflow chamber 22, and the sleeve 25 and the end wall 24 are connected.
A seal 28 is interposed therebetween. In this case, the gap size of the gap 27 is preferably smaller than the bead diameter.

In this apparatus, a slurry in which water and ceramic particles are mixed is supplied into the stirring tank 2 from the inlet 5 through the gap 27, and is stirred together with the beads sealed inside the tank as in the apparatus of FIG. Then, the beads are separated in the medium separating section 4, and the slurry after the treatment is taken out from the outlet 10.

[0026]

As is apparent from the above description, according to the first aspect of the invention, the impact on the ceramic particles is reduced to prevent the powder from being excessively crushed into fine powder, and the power to be supplied is also reduced. .

Further, since the medium separation section is provided above the blade section, a mixture containing a small amount of dispersion medium can be processed, and the separation operation can be performed efficiently.

According to the second aspect of the present invention, since the front surface of the blade portion is set to the receding surface, there is an advantage that the impact can be reduced and the working time of the blade portion can be extended to increase the fine work.

According to the third aspect of the present invention, the agitator can be manufactured by using one or a small number of blades, so that there is an advantage that the agitator can be manufactured at low cost.

According to the fourth aspect of the present invention, the impact on the ceramic particles having a multilayer structure, an inclined structure, etc. is reduced to prevent the powder from being excessively pulverized into fine powders. Can be manufactured.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a first embodiment of the present invention.

FIG. 2 is a front view of a slat.

FIG. 3 is a partial perspective view of a stirring body.

FIG. 4 is an explanatory view of a crushing action.

FIG. 5 is a perspective view of a modified example of a blade.

FIG. 6 is a longitudinal sectional view of a second embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 2 Stirring tank 3 Stirrer 4 Media separator 5 Supply port 8 Centrifuge 10 Outlet 11, 11a Blade 12 Drive shaft 13 Blade 13a Front surface 14 Valley 17 Spiral 20 Screw 26 Flange 27 Gap M mixture

Claims (4)

[Claims] 1. A bead-shaped dispersion medium is accommodated in a stirring tank provided with a stirring body having a blade portion on the outer periphery, and stirring is performed while continuously supplying a slurry of ceramic particles to the stirring tank.
In the ceramic particle pulverizing device for discharging the slurry after stirring from the medium separating unit, the blade of the stirring body is provided in a range of not less than 2/3 of the inner diameter of the stirring tank, and the blade is moved in the longitudinal direction of the stirring body by the blade. A spiral is formed from both ends to the center to propel the slurry and the dispersion medium, and a centrifugal separation type medium separation unit is provided above the center line of the stirrer, and the driving source for the blade unit and the driving source for the medium separation unit are separated. An apparatus for crushing ceramic particles, comprising: 2. The ceramic particle pulverizing device according to claim 1, wherein the front surface in the rotation direction of the blade portion is a surface whose outer peripheral side is recessed from the center side. 3. A ceramic according to claim 1, wherein the blades are twisted by fixing a plurality of blades provided with blades on the outer periphery to a drive shaft with a phase shift. Particle crusher. 4. A bead-shaped dispersion medium is accommodated in a stirring tank provided with a stirring body having a blade portion on the outer periphery, and the slurry is stirred while continuously supplying a slurry of ceramic particles to the stirring tank.
In the method of pulverizing ceramic particles for discharging the slurry after stirring from the medium separation unit, the blades of the stirring body are provided in a range of not less than 2/3 of the inner diameter of the stirring tank, and the blades are arranged at both ends in the longitudinal direction of the stirring body. A spiral body for driving the slurry and the dispersion medium is formed in the center, and a medium separation unit of a centrifugal separation type is provided above the center line of the stirring body, and the peripheral speed of the blade unit is 1 to 6 m.
/ S, and the peripheral speed of the medium separation unit is set to be higher than or equal to the peripheral speed of the blade unit.