JP7378253B2 - Grinding method - Google Patents

Description

The present invention relates to a media agitation type pulverizer equipped with a centrifugal separator, and relates to a pulverization system, a pulverizer, and a pulverization method for turning solid particles in a slurry of processed material into fine particles.

Wet crushers using media are used in a wide range of fields, including printer inks, paints, polymerized toners, color resists, ceramic particles, titanium oxide, metal powders, and pharmaceuticals. In this specification, the term "pulverization treatment" includes the dispersion treatment for breaking up aggregated particles.

Patent Document 1 describes a media stirring type pulverizer that pulverizes a slurry of a processed material. In this crusher, a tubular rotating shaft is inserted through the side wall of one end of a cylindrical crushing container, and a centrifugal separator and a stirring member for stirring the inside of the crushing container are attached to this rotating shaft. Furthermore, the crushing container is equipped with a cooling jacket on the outer periphery, and the processed material in the crushing container can be cooled by flowing a cooling medium into the jacket.
Here, the processed material slurry is supplied from one end side wall of the pulverization container, undergoes pulverization treatment within the container, is separated from the media, and is discharged from the inside of the tube of the rotating shaft.

A media agitation type pulverizer has the property that the particle size of solid particles after pulverization is determined by the diameter of the media used. That is, as the required product particle size decreases, the particle size of the media used also decreases. In Patent Document 1, a medium having a diameter of 0.03 to 0.1 mm is used to process particles into nano-order particles.

However, such a crusher has a problem in that the crushing ratio cannot be increased very much. The grinding ratio is the ratio of the particle sizes of raw material particles and product particles.
The particle size distribution will be described later, but if ideal pulverization is performed, the product particles will have a sharp particle size distribution with sharp peaks. On the other hand, if inappropriate pulverization is performed, product particles will have a broad particle size distribution with two peaks.

The fact that the particle size distribution after the pulverization treatment has two peaks indicates that sufficient product particles cannot be obtained by one pulverization treatment, and a two-stage treatment is necessary.
In other words, in the first stage, a large diameter media is used to perform the pulverization process, and the slurry obtained from that process is then pulverized again in the second stage, using a small diameter media. Become.

FIG. 10 shows a schematic configuration of a pulverization processing system 200 that performs two-stage processing.
The pulverization processing system 200 includes two media agitation type pulverizers 111 and 112, two pumps 181 and 182, and a holding tank 160.
The crushers 111 and 112 are equipped with cooling jackets on the outside of the crushing containers 111a and 112a in order to remove heat generated by stirring, and are connected to lines 196, 197, 198, and 199 for flowing a cooling medium. .

Then, the raw material slurry is put into a holding tank 160 equipped with an agitator 161, one pulverizer 111 is filled with large media (for example, 0.5 mm in diameter), and the other pulverizer 112 is filled with small media ( For example, a diameter of 0.1 mm) is filled.
The first-stage crushing process is performed using the crusher 111, the pump 181, and the holding tank 160, and after this process is completed, the second-stage crushing process is performed.
The second-stage crushing process is performed using the crusher 112, pump 182, and holding tank 160.

On the other hand, Patent Document 2 discloses a pulverizer that solves the problem of solid particles in slurry settling and adhering inside the equipment and the problem of increased pressure loss when equipment such as a cooler is placed in the circulation line. The processing system is described.

Japanese Patent Application Publication No. 2007-229686 Japanese Patent Application Publication No. 2017-192876

However, in the crushing system 200 that performs the two-stage process as described above, the equipment becomes expensive because two crushers 111 and 112 are used. Furthermore, since the same pulverization process is performed twice, the time required for the pulverization process becomes longer, and the time required for preparation for the process and the time required for cleaning and maintenance also become longer.

Therefore, an object of the present invention is to provide an inexpensive pulverization system, a pulverizer, and a pulverization method that can obtain a large pulverization ratio in one stage of processing.

In order to achieve the above object, the pulverization processing system of the present invention is a pulverization processing system that pulverizes solid particles in a slurry using a media agitation type pulverizer, and includes a cylindrical resin pulverization container. a holding tank for the processed material connected to the grinder via a circulation line having a circulation pump; a cooler connected to a tank, and the crusher includes a stirring member for stirring the processed material and media, and a stirring member for stirring the processed material and the media, and a stirring member for stirring the processed material and the media, and a tubular rotating shaft inserted through the side wall of one end of the crushing container. A separator is attached to separate the particles from the media, and the outer peripheral speed of the stirring member can be set to a speed exceeding 20 m/sec.

The invention of a crusher is also a media agitation type crusher that atomizes solid particles in a slurry, which includes a cylindrical crushing container and a tubular rotating shaft inserted through a side wall of one end of the crushing container. and a stirring member attached to the rotating shaft to stir the processed material and the media, and a separator to separate the solid particles from the media, and the grinding container is made of resin.
Here, the stirring member and the separator may also be made of resin.

Furthermore, the invention of a pulverization processing method is a pulverization processing method in which solid particles in a slurry are pulverized using the pulverizer of the above pulverization processing system, the processing material being put into the holding tank and the pulverizer a step of stirring the media filled with the material by rotating it at high speed at a peripheral speed of the stirring member exceeding 20 m/sec; cooling the processed material sent through the cooling line with the cooler; The method is characterized by repeating the step of returning to the holding tank.
Here, it is preferable that the average residence time of the processed material in the pulverizer is 60 seconds or less.

The pulverization processing system of the present invention configured as described above includes a media agitation type pulverizer having a cylindrical resin pulverization container, and the outer circumferential speed of the stirring member that stirs the inside of the pulverization container exceeds 20 m/sec. speed can be set. Further, a cooler for cooling the processed material is connected to the holding tank via a cooling line having a pump.

If equipped with a cooler connected via a cooling line, it is possible to efficiently remove heat generated by rotating the stirring member at high speed, and achieve a large pulverization ratio in one stage of processing. You will be able to obtain Furthermore, by simplifying the system with one-stage processing, it becomes possible to significantly reduce equipment costs and operating costs. Furthermore, if the crushing container is made of resin, it can be manufactured at low cost.

In addition, in the invention of the crusher, the crushing container is formed of a resin material with low thermal conductivity, so the structure is simplified as there is no cooling means on the outer periphery of the crushing container, and it is significantly lighter. can be converted into Therefore, the manufacturing cost is low, and the structure is excellent in workability.

Furthermore, in the invention of the pulverization processing method, when the processing material and the media are stirred and processed in the pulverizer, the heat generated by rotating the stirring member at a high speed at a peripheral speed of more than 20 m/sec. It can be efficiently cooled by a cooler connected with a cooling line. Further, by setting the average residence time of the processed material in the pulverizer to 60 seconds or less, the temperature rise of the processed material can be suppressed.

1 is a flowchart showing a schematic flow of a pulverization processing system according to an embodiment of the present invention. FIG. 2 is a diagram illustrating the configuration of a crusher, in which (a) is a schematic cross-sectional view of the whole, (b) is an explanatory diagram of the size of a crushing container, and (c) is an explanatory diagram of the size of a stirring member. FIG. 2A is a schematic cross-sectional view taken in the direction of the arrow AA in FIG. 2(a). FIG. 2 is a diagram illustrating the particle size distribution in Example 1, in which (a) is a particle size distribution diagram of the raw material, (b) is a particle size distribution diagram after 60 minutes treatment, and (c) is a particle size distribution diagram after 120 minutes treatment. be. 3 is a graph showing changes in particle size over time during the pulverization process of Example 1. FIG. 2 is a diagram illustrating the particle size distribution in Comparative Example 1, in which (a) is a particle size distribution diagram of the raw material, (b) is a particle size distribution diagram after 120 minutes treatment, and (c) is a particle size distribution diagram after 240 minutes treatment. be. 3 is a graph showing changes in particle size over time in the pulverization process of Comparative Example 1. FIG. 3 is a diagram illustrating the particle size distribution in Comparative Example 2, in which (a) is a particle size distribution diagram of the raw material, (b) is a particle size distribution diagram after 60 minutes treatment, and (c) is a particle size distribution diagram after 120 minutes treatment. be. 3 is a graph showing changes in particle size over time in the pulverization process of Comparative Example 2. 1 is a flowchart showing a schematic flow of a conventional pulverization processing system that performs two-stage processing.

A pulverization processing system 100 according to an embodiment of the present invention will be described with reference to FIG.
The pulverization processing system 100 of this embodiment includes a media stirring type pulverizer 10, a holding tank 60 for the processed material, and a cooler 70 for the processed material.
One batch of the processed material slurry, which is a slurry containing solid particles, is put into a holding tank 60 and stirred by a stirrer 61 to maintain a uniform concentration.

The slurry to be processed is extracted from the bottom of the holding tank 60 through a line 90, and a part of it is sent to the crusher 10 by a circulation pump 81 through a line 91 that constitutes a circulation line, where it is subjected to a crushing process. , and is returned to the holding tank 60 by line 92. The pulverization process is performed for a predetermined period of time while the processed material is being circulated in this manner.

The crusher 10 performs the crushing process by stirring the slurry of the processed material and the media within the cylindrical crushing container 20 . The crusher 10 includes a relatively large electric motor 11 to rotate the stirring member 40 at high speed. In addition, in order to reliably separate the solid particles and the media, the pulverization process is performed with the rotating shaft 30 (see FIG. 2(a)) vertical. In order to facilitate maintenance, it is preferable that the rotating shaft 30 be horizontal, so that the entire structure can be rotated by 90 degrees with respect to the support column 12.

In the pulverization processing system 100, the amount of heat generated in the pulverizer 10 is very large due to high-speed agitation of the processed material and media. The temperature rise of the processed material can be suppressed to a small level. That is, by shortening the average residence time of the processed material in the crusher 10, the temperature rise of the processed material is suppressed. Such control of the passage speed (average residence time) is performed by setting or operating the circulation pump 81.

On the other hand, the other part of the processed material slurry extracted through line 90 is sent by pump 82 from line 95 constituting a cooling line to cooler 70 , where it is cooled and then returned to holding tank 60 through line 96 . It will be done. Lines 98 and 99 for flowing a cooling medium are connected to the cooler 70.

It is preferable that the cooler 70 has a structure in which the slurry of the processed material does not stagnate in order to avoid sedimentation and adhesion of particles. For this reason, it is preferable to have a structure in which the slurry to be treated is passed through a pipe with a constant cross-sectional area, and the outside of the pipe is cooled with a cooling medium. Further, it is preferable to use a configuration that allows the interior of the pipe to be reliably inspected and cleaned.

The models of the circulation pump 81 and the pump 82 can be freely selected depending on the properties of the slurry to be processed, etc., but because a constant flow rate can be stably obtained, the flow rate can be easily set. Therefore, it is preferable to use a metering pump.

Next, the crusher 10 used in the crushing system 100 of this embodiment will be described with reference to FIGS. 2 and 3.
FIG. 2(a) is a schematic cross-sectional view taken along a plane passing through the axis of the rotating shaft 30, and FIGS. 2(b) and 2(c) are diagrams for explaining the dimensional relationship between the crushing container 20 and the stirring member 40. It is. FIG. 3 is a cross-sectional view taken along the line AA in FIG. 2(a).

The crusher 10 is provided with a tubular rotating shaft 30 that passes through the side wall of one end of the cylindrical crushing container 20. The rotating shaft 30 includes a stirring member 40 that stirs the processed material and media, and a stirring member 40 that stirs the processed material (solids). A separator 50 is attached to separate particles (particles) and media. This crushing container 20 is made of resin and is not equipped with a cooling means such as a jacket, as will be described later.

In the crushing container 20, a container main body 25 and a lid member 26 are integrally connected at a flange portion with bolts 29. A stirring member 40 and a separator 50 are arranged in the container body 25 to form a crushing chamber. A rotating shaft 30 is inserted through the lid member 26 and sealed by a shaft seal 35 . Further, the lid member 26 is provided with a supply port 21 for the slurry of the processed material.

The stirring member 40 has a cylindrical member formed with a plurality of flow passages 41 penetrating inside and outside, thereby forming a plurality of blades 42. Therefore, when the stirring member 40 is rotated in the direction of the arrow in FIG. 3, the slurry and the media flow violently from the inside to the outside of the flow path 41, and return from the outside to the inside through the lower end. A circular flow is formed.
By setting the outer circumferential speed of the stirring member 40 to a speed exceeding 20 m/sec, the crusher 10 can form a stirring circulating flow having crushing energy with strong destructive power.

The separator 50 is located inside the stirring member 40 and rotates together with the stirring member 40.
The separator 50 also has a cylindrical member formed with a plurality of flow passages 51 penetrating the inside and outside, and a plurality of blades 52. However, since the bottom portion is closed by the bottom plate 55 (FIG. 2(a)), no circulating flow is generated even when the rotation is made.

The lower end of the tubular rotating shaft 30 is located in the inner space 53 of the separator 50, and the opening 33 is provided in the tube wall, so that the inner space 53 and the inner tube 32 of the rotating shaft 30 communicate with each other. are doing. Therefore, the slurry of the processed material forming the stirring circulation flow enters the pipe 32 of the rotating shaft 30 via the separator 50 and is discharged from the discharge port 31.

The slurry to be treated flows through the flow path 51 from the outside to the inside, so it is subjected to centrifugal force due to the rotation of the blade 52. This allows the finely divided solid particles to pass into the tube 32, while the media and large solid particles are forced back into the agitated circulation flow by centrifugal force.
As a result, only the processed material slurry separated from the media can proceed to the discharge port 31, and the media remains in the crushing container 20 as it is. This is the separation function of the separator 50, and is called a centrifugal type.

Next, the characteristics of the crusher 10 will be explained.
First, as shown in FIGS. 2(b) and 2(c), the external volume Vr of the stirring member 40 is significantly larger than the internal volume V of the crushing container 20. The external volume Vr of the stirring member 40 is 50% or more, preferably 60 to 70%, of the internal volume V of the crushing container 20.

This indicates that the stirring circulation flow of the processed material slurry and media generated in the crusher 10 is a circulation flow throughout the crushing container 20. That is, this means that the slurry of the processed material and the media are vigorously stirred throughout the entire pulverizing container 20, and the pulverizing process is performed throughout the pulverizing container 20. Then, the inside of the crushing container 20 is in a completely mixed state.

Another feature is that the diameter D of the crushing container 20 is larger than the length L in the axial direction. That is, L/D is smaller than 1, preferably about 1/3. For this reason, the diameter Dr of the stirring member 40 is also larger than the length Lr in the axial direction. Due to these dimensional relationships, it is believed that the stirring member 40 imparts maximum kinetic energy to the processed material and the media within a limited space.
By reducing L/D in this way, the dispersion force increases, making it difficult for the media to become unbalanced, and it also becomes possible to increase the flow rate, thereby suppressing the temperature rise within the crushing container 20. becomes possible.

Furthermore, the separator 50 in the crusher 10 has excellent features.
That is, even if the amount of processed material slurry supplied to the crusher 10 is significantly increased, the separator 50 can exhibit stable separation performance. Further, even when the stirring member 40 is rotated at high speed to form a vigorous stirring circulating flow, the separator 50 rotates at high speed together with the stirring member 40, and therefore can exhibit stable separation performance.

The pulverization processing system 100 of this embodiment is characterized in that processing is performed at an outer circumferential speed of the stirring member 40 exceeding 20 m/sec. By performing high-speed stirring, the amount of heat generated in the crusher 10 usually becomes very large. On the other hand, the excellent separation performance of the separator 50 of the crusher 10 makes it possible to significantly increase the supply amount of the slurry of the processed material, thereby suppressing the temperature rise of the processed material and ensuring stable pulverization. can be continued.

Here, the amount of heat generated will be explained.
For example, when the crushing container 20 is filled with a predetermined amount of media and about 3 liters of slurry, and the peripheral speed of the stirring member 40 is 20 m/sec, the power consumption is about 6.6 KW. At 25 m/sec, the power increases rapidly to about 13.4 KW. Hereinafter, in order to simplify the explanation, numerical values are shown as approximate values.
The power of 6.6 KW is the amount of heat that increases the temperature of 3 liters of material to be processed by 0.5° C. per second, and the power of 13.4 KW is the amount of heat that increases the temperature of the object to be processed by 1° C. per second.

The temperature rise in the pulverizer 10 can be set to at least 30°C or lower to enable pulverization, and the temperature rise to 20°C or lower allows stable pulverization.
For this reason, when the peripheral speed of the stirring member 40 is 20 m/sec, the residence time of the processed material in the crushing container 20 is preferably at most 60 seconds or less, and more preferably 40 seconds or less.
Furthermore, when the peripheral speed of the stirring member 40 is 25 m/sec, the residence time of the processed material in the crushing container 20 is preferably 30 seconds or less at most, and more preferably 20 seconds or less.

In order to suppress the temperature rise in the crusher 10 as described above, shortening the residence time of the processed material in the crusher 10 has not been considered at all in conventional crushing techniques.
Even if a cooling jacket is provided to cover the outer periphery of the crushing container 20 of the crusher 10, it is difficult to maintain a stable temperature state due to such a large amount of heat generated by high-speed rotation. It is. Therefore, in the pulverization processing system 100 of this embodiment, the pulverizer 10 itself is not provided with any cooling means. That is, all cooling of the processed material is performed by external cooling using a cooler 70 connected via a cooling line.

Since this cooling line is equipped with its own pump 82 in addition to the circulation pump 81 of the circulation line, cooling can be performed at a sufficiently high flow rate to prevent sedimentation or adhesion within the cooler 70. Furthermore, since the pump 82 can stabilize the flow rate of the slurry to be processed that is supplied to the cooler 70, stable temperature control by the cooler 70 is possible, and an abnormal rise in temperature can be prevented.

By not providing the crushing container 20 with a jacket or the like in this manner, the structure of the crushing container 20 can be greatly simplified.
Generally, when providing a jacket, it is necessary to use a metal with high thermal conductivity, but if heat conduction is not taken into account, a resin material with a light specific gravity can be used. Therefore, a resin material is used for the peripheral wall and bottom surface portion, which are the main components of the crushing container 20 of the crusher 10 of this embodiment.

As the resin material, polyamide resin such as nylon resin can be used. Furthermore, when chemical resistance is required, fluororesin or the like can be used. Since these materials are lightweight, workability in processing operations is improved and equipment with high safety can be provided. Moreover, if the crushing container 20 is made of resin, it can be manufactured at low cost.
Furthermore, the stirring member 40 and the separator 50 can also be formed from a resin material.

Next, the pulverization process using high-speed stirring will be explained.
By setting the outer circumferential speed of the stirring member 40 to a speed exceeding 20 m/sec, it becomes possible to obtain large crushing energy that could not be obtained conventionally, and it is possible to crush solid particles on the micron order into fine particles on the nano order. It becomes like this. Here, as the media to be filled into the crushing container 20, it is preferable to use media having a diameter of 0.1 mm or less.

It has been said that when high-speed stirring is performed by the stirring member 40, fine particles that have been crushed once re-agglomerate, but by using media with a diameter of 0.1 mm or less, fine particles can be finely crushed without causing re-agglomeration. be able to process.
Furthermore, it has been said that such high-speed stirring causes severe wear on the grinding container 20 and the stirring member 40, but this may become a practical problem when using media with a diameter of 0.1 mm or less. It causes almost no wear. Furthermore, although it depends on the processed material, if the raw material is one that will be fired in a subsequent process, the fine powder of the resin material will be burned off and will not remain.

Using a resin material with low thermal conductivity as a member of the crushing container 20 in this manner would have been unthinkable when using a cooling jacket. However, in the pulverization processing system 100 of this embodiment, since the cooler 70 is connected via a cooling line, a resin material with low thermal conductivity can be used for the pulverization container 20. Furthermore, by using the crushing container 20 made of resin with low thermal conductivity, it is less susceptible to the influence of outside air, and the temperature of the processed material can be easily controlled, allowing stable crushing to be performed.

With the pulverization processing system 100 of this embodiment configured as described above, it is possible to increase the pulverization ratio in the pulverization processing in which the solid particles in the slurry of the processed material are on the nano-order. In other words, it is possible to finish the process in a short time with one pulverization process, the particle size distribution of the product particles has a sharp peak, and a large pulverization ratio is achieved when comparing the median diameter and maximum diameter. You will be able to do this.

Further, in one pulverization process, it is possible to perform pulverization processing such that the pulverization ratio is about 100 when converting a micron-order raw material slurry into a nano-order product slurry. By enabling one-stage processing in this manner, the system configuration of the pulverization processing system 100 can be simplified, and equipment costs and operating costs can be significantly reduced.

Furthermore, the pulverization processing method of this embodiment is a pulverization processing method in which solid particles in a slurry are pulverized using the pulverizer 10 of the pulverization processing system 100. Then, the process material put into the holding tank 60 and the media filled in the crusher 10 are stirred by rotating at high speed at a peripheral speed of the stirring member 40 exceeding 20 m/sec, and the material is fed through a cooling line. The process of cooling the processed material in the cooler 70 and returning it to the holding tank 60 is repeated for a predetermined period of time.

In this way, when the slurry of the processed material and the media are stirred and processed in the crusher 10, the heat generated by rotating the stirring member 40 at high speed is efficiently absorbed by the cooler 70 connected to the cooling line. can be cooled to Further, by setting the average residence time of the processed material in the crusher 10 to 60 seconds or less, it is possible to suppress the temperature rise of the processed material.

Hereinafter, an experiment in which the performance of the pulverization processing system 100 described in the embodiment was confirmed will be described with reference to FIGS. 4 to 9. Note that parts that are the same or equivalent to those described in the above embodiment will be described using the same terms or the same symbols.

In Example 1, calcium carbonate was pulverized using the pulverization system 100 under the following conditions. After starting the crusher 10, samples were taken from the line 92 at predetermined intervals and their particle size distribution was measured.
Grinding machine 10: Total volume of grinding container 20: approximately 6.5 liters
Volume for processing material and media: Approximately 4.5 liters Stirring member 40: Peripheral speed: 25 m/sec Media: Material: Zirconia
Shape Diameter 0.1mm
Amount used: 1.36 liters Processed material: Calcium carbonate
Usage amount: 3kg
solvent water
Slurry concentration 10wt%
Flow rate of line 91: 8 liters/min
Residence time in crusher 10: 24 seconds
Flow rate of line 95: 35 liters/min

FIG. 4 shows the particle size distribution in Example 1. FIG. 4(a) shows the particle size distribution of the raw material for the slurry of the processed material initially charged into the holding tank 60, and FIG. 4(b) shows the particle size distribution of the sample collected after 60 minutes of pulverization. c) is the particle size distribution of a sample collected after 120 minutes of pulverization.
In the particle size distribution, the horizontal axis shows the particle diameter (μm) on a logarithmic scale, and the vertical axis shows the frequency (%). The left end of the graph shows the minimum particle size, and the right end shows the maximum particle size. Then, the particle sizes are compared, with the particle size at which the cumulative value is 50% when the frequencies (%) are accumulated starting from the left as the median diameter, and the particle size at which the cumulative value is 100% as the maximum diameter.

In Example 1, the median diameter of the raw material was 6.674 μm, and the maximum diameter was 52.33 μm (FIG. 4(a)). After this raw material was pulverized for 60 minutes, it had a sharp particle size distribution with sharp peaks (FIG. 4(b)). At this time, the median diameter was 0.187 μm, and the maximum diameter was 0.818 μm. When the grinding ratio is calculated from the results thus far, it is 35.7 at the center diameter and 64.0 at the maximum diameter. Furthermore, after the pulverization treatment for 120 minutes, the median diameter was 0.159 μm and the maximum diameter was 0.486 μm (FIG. 4(c)). As a result, the grinding ratio is 42.0 at the center diameter and 107.7 at the maximum diameter.

In Figure 5, the horizontal axis shows the pulverization processing time (Hr), the vertical axis shows the particle size at the median diameter (50% cumulative) and the maximum diameter (100% cumulative), and shows the change in particle size with respect to time. There is. The median diameter becomes 1 μm or less after 20 minutes of pulverization, and the maximum diameter becomes 1 μm or less after 1 hour of pulverization.

<Comparative example 1>
Subsequently, as Comparative Example 1, pulverization was performed under the same conditions as in Example 1 except that the outer circumferential speed of the stirring member 40 was set to 16 m/sec. FIG. 6 shows the particle size distribution in Comparative Example 1.
FIG. 6(a) shows the particle size distribution of the raw material of the processed material slurry initially charged into the holding tank 60, and is the same as the particle size distribution of Example 1 (FIG. 4(a)). FIG. 6(b) shows the particle size distribution of a sample taken after pulverization for 120 minutes, and FIG. 6(c) shows the particle size distribution of a sample taken after pulverization for 240 minutes.
Looking at FIGS. 6(b) and 6(c), both have two peaks, indicating a broad particle size distribution.

FIG. 7 shows the change in particle size in the median diameter and maximum diameter in Comparative Example 1 using a graph similar to FIG. 5 in Example 1. The median diameter is reduced to 1 μm or less after 90 minutes of pulverization, but the maximum diameter is 30 μm even after 4 hours of pulverization, which shows almost no progress in refining.

<Comparative example 2>
In Comparative Example 2, the peripheral speed of the stirring member 40 was set to 20 m/sec, and the crushing process was performed under the same conditions as in Example 1 except for the above. FIG. 8 shows the particle size distribution in Comparative Example 2.
FIG. 8(a) shows the particle size distribution of the raw material of the processed material slurry initially charged into the holding tank 60, and is the same as the particle size distribution of Example 1 (FIG. 4(a)). FIG. 8(b) shows the particle size distribution of a sample collected after pulverization for 60 minutes, and FIG. 8(c) shows the particle size distribution of a sample collected after pulverization for 120 minutes. In Comparative Example 2, the particle size distribution was broad in FIG. 8(b) after pulverization for 60 minutes, but changed to a sharp particle size distribution in FIG. 8(c) after pulverization for 120 minutes.

FIG. 9 shows the change in particle size of the median diameter and maximum diameter in Comparative Example 2 using a graph similar to FIG. 5 of Example 1. The median diameter becomes 1 μm or less after 30 minutes of pulverization, and the maximum diameter decreases rapidly after 60 minutes of pulverization and becomes 1 μm or less after 90 minutes. This indicates that the right side of the broad particle size distribution (FIG. 8(b)) disappeared during the subsequent 30-minute grinding process.

From the above results, the outer peripheral speed of the stirring member 40 has a boundary around 20 m/sec in Comparative Example 2, a speed below this (Comparative Example 1) requires two-stage processing, and a speed exceeding 20 m/sec It can be said that by setting this, processing can be performed in one stage.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes that do not depart from the gist of the present invention may be made to the present invention. included.
For example, the flow of the slurry to be processed may include a flow circulating through the pulverizer 10 (circulation line) and a flow circulating through the cooler 70 (cooling line), and the other configurations of the pulverization processing system 100 are as follows. It is not limited to the description of the form.

100: Grinding system 10: Grinding machine 20: Grinding container 30: Rotating shaft 40: Stirring member 50: Separator 60: Holding tank 70: Cooler 81: Circulation pump 82: Pump 91: Line (circulation line)
95: Line (cooling line)

Claims (2)

A media agitation type pulverizer having a cylindrical resin crushing container, a holding tank for the processed material connected to the pulverizer via a circulation line having a circulation pump, and a pump for cooling the processed material. a cooler connected to the holding tank via a cooling line having A pulverization treatment method for pulverizing solid particles in a slurry using the pulverizer of a pulverization treatment system that is equipped with a stirring member that stirs the material and a separator that separates the processed material and the media, the method comprising:
When the peripheral speed of the stirring member is 20 m/sec, the residence time of the processed material in the grinding container is 60 seconds or less for the processed material input into the holding tank and the media filled in the pulverizer, stirring under high-speed rotation with a residence time of 30 seconds or less when the speed is 25 m/sec ;
A pulverization processing method characterized by repeating the steps of cooling the processed material sent through the cooling line in the cooler and returning it to the holding tank. According to claim 1, the residence time of the processed material in the crusher is 40 seconds or less when the outer circumferential speed of the stirring member is 20 m/sec, and 20 seconds or less when the outer circumferential speed of the stirring member is 25 m/sec. The grinding treatment method described.