JP5726478B2 - Classification method and classification tube - Google Patents

Description

  The present invention relates to a classification method for wet classification of a porous material or resin of ceramics and particulate materials such as the porous material, and a classification tube used therefor.

  Ceramic porous bodies and resins produced by pulverization or synthesis and particulate substances such as porous bodies have a wide particle size distribution. When fine particles are mixed, problems such as clogging of the filter with fine particles occur in a process using a ceramic porous body, a resin, and the porous body. As a method for removing fine particles, a sieve is generally used. However, since the sieve is clogged, it cannot be efficiently removed.

  Therefore, a hydraulic classification method is effective in which water is supplied from the bottom of the classification tank containing the classification target particles to create an upward flow, and classification is performed using the difference in sedimentation speed. However, the conventional hydraulic classification method requires a large classification tank having a special structure and a pump with a large flow rate, and the liquid flow rate is small when only fine particles of small density particles are separated. There was a problem that a retention part was formed at the bottom and classification efficiency was lowered (Patent Documents 1 to 3).

JP 2000-301022 A JP 2001-87673 A Japanese Patent Application Laid-Open No. 2004-113962

  The present invention has been made in view of the above-described problems, and an object thereof is to provide an efficient and low-cost classification method without requiring a large-sized classification tank having a special structure.

In the classification method of the present invention that solves the above-mentioned problems, the particles to be classified are added to a classification tank together with a liquid medium, and this is stirred to prepare a classification liquid, and a liquid inlet is provided in the classification liquid in the classification tank. A classification tube is inserted so as to communicate with the classification liquid, and the classification liquid is sucked from the liquid outlet of the classification pipe while continuing the stirring in the classification tank, thereby allowing the classification liquid to pass through the classification pipe. And removing fine particles.
The classification tube used in the classification method of the present invention is preferably provided with at least one baffle on the liquid inflow side. Moreover, it is preferable to provide at least one rib on the liquid outflow side in the classification tube used in the classification method of the present invention.

  According to the classification method of the present invention, it is possible to classify a porous material of ceramic, a resin, and a granular material such as the porous material without the need for a large-sized classification tank having a special structure or a pump having a large flow rate. In addition, it can be performed at low cost.

It is an example of the apparatus for enforcing the classification method of this invention. It is an example of the classification tube used for the classification method of this invention. It is another example of the apparatus for enforcing the classification method of this invention. It is a figure which shows the relationship between the processing time and the particle removal rate of the example which removed the microparticles | fine-particles by the classification method of this invention.

  In the classification method of the present invention, classification target particles are added to a classification tank together with a liquid medium, and this is stirred to prepare a classification liquid, and a liquid inlet communicates with the classification liquid in the classification liquid in the classification tank. In such a manner, the classification liquid is sucked from the liquid outlet of the classification pipe while continuing the stirring in the classification tank so that the fine particles are removed by passing the classification liquid through the classification pipe. It is characterized by doing. In the classification method of the present invention, the classification liquid is stirred and mixed in the classification tank, and classification is performed by inhaling one of the classification tubes inserted into the classification liquid, so that high classification efficiency is obtained. Moreover, an existing stirring tank can be used without requiring a large classification tank having a special structure.

Hereinafter, the classification method of the present invention will be described in more detail with reference to the drawings.
The classification method of the present invention can be applied regardless of the shape of the particles as long as the particles do not dissolve in the liquid medium (generally water is used) and the density is higher than that of the liquid medium. Can be suitably used for particles having a density of 2000 Kg / m ³ or less, such as ceramic porous bodies and resins, and particulate materials such as porous bodies, which is relatively difficult to perform by the hydraulic classification. The particle size of the particles to be classified that can be classified by the classification method of the present invention can vary depending on the particle density, liquid medium density, pump performance, etc., but particles having a particle size of about several μm to several hundred μm can be classified. .

FIG. 1 shows an outline of an example of an apparatus for carrying out the classification method of the present invention.
The classification tank 1 used in the classification method of the present invention only needs to be able to stir the classification liquid 2 composed of the classification target particles and the liquid medium using the stirrer 3 and the like, and does not require a special structure. An existing stirring tank may be used.

  The stirrer 3 only needs to have a stirring blade capable of floating particles, and examples of the stirring blade of the stirrer 3 include a propeller, an inclined paddle, a turbine, a fiddler, and an anchor type.

  Details of an example of the classification tube 4 used in the classification method of the present invention are shown in FIG. As shown in FIG. 2A, the classification tube 4 is configured so that the classification liquid can pass upward from the liquid inlet 21 to the liquid outlet 22. The shape of the classification tube 4 is preferably a cylindrical shape in order to form a uniform flow, but may be a quadrangular prism shape or a triangular prism shape. It is preferable that the liquid outlet port of the classification tube 4 has a conical shape with a narrowing angle of 90 ° or less so that the flow is not disturbed. The diameter of the classification tube 4 can be inserted into the classification tank 1, and the classification can be performed in a shorter time as the pump suction amount is not restricted. However, about 50 mm to 1000 mm is preferably used. The length of the classification tube 4 is preferably 2 to 10 times the diameter. If it is too short, it is difficult to form a uniform flow, and a sufficient classification effect cannot be obtained. Moreover, when too long, the weight of a classification tube will increase and there exists a problem which becomes difficult to hold | maintain. Preferably, it is about 2.5 to 6 times the diameter.

  The classifying pipe of the present invention is preferably provided with a baffle 23 on the inner wall on the side of the lower liquid inlet. By providing the baffle 23, there is no influence of the liquid flow due to the stirring of the classification tank, and the restriction of the stirring conditions is eliminated. For example, four baffles 23 can be provided equally as shown in FIG. The width of the baffle 23 is preferably 1/10 or more of the diameter of the classification tube 4, and the length of the baffle 23 is preferably 1/20 or more of the length of the classification tube 4.

  Moreover, it is preferable that the classifying pipe of the present invention is provided with a rib 24 as shown in FIG. Since there is almost no liquid flow near the inner wall of the classification tube, the particles descend around the wall surface and the classification efficiency decreases. However, by providing the rib 24, the particles that descend are guided to a region where the liquid flow is present, and the classification efficiency is improved. Can be improved. The height of the rib 24 is preferably about 1 to 10 mm.

Next, the procedure of the classification method of the present invention will be described.
First, the classification target particles having a wide particle size distribution are added to the classification tank 1 together with the liquid medium, and this is stirred to prepare a slurry-like classification liquid 2. Next, while stirring the classification tank 1, the liquid inlet 21 of the classification pipe 4 is inserted in the vertical direction so as to communicate with the classification liquid 2 in the classification tank 1. The insertion position of the classification tube 4 at this time can be arbitrarily set in a range that does not contact the stirring blade and does not contact the wall surface of the classification tank 1 in the lateral direction. Further, the vertical direction can be arbitrarily set within a range in which air does not get in from the liquid inlet 21 without contacting the bottom of the classification tank 1, but the liquid flow caused by the stirring blades should be as far as possible from the stirring blades. It is preferable because it is not easily affected. Then, the classification liquid 2 is sucked from the liquid outlet 22 of the classification pipe 4 by the pump 5 at a constant speed so that the liquid speed in the classification pipe is rectified. Here, the constant speed is a liquid flow rate obtained from the Stokes equation, which can separate particles having a particle diameter to be separated. The suction speed can be adjusted using the flow meter 6 or the like. The fine particles sucked and removed from the classification tube 4 in this way are sent to the filter 7 where they are collected by filtration, and the filtrate is supplied to the classification tank 1 again. Such classification operation is performed for a predetermined time. The removal of the fine particles can also be performed using a separation tank 8 as shown in FIG. In addition, classification processing may be performed using a plurality of classification tubes.

  Hereinafter, although the classification method of this invention is demonstrated in detail by an Example, this invention is not limited to these.

Example 1
A copolymer of 4-vinylpyridine and divinylbenzene (density 1100 Kg / m ³ ) was synthesized by suspension polymerization. As a result of measuring the particle size of the obtained resin beads with a laser diffraction / scattering particle size distribution measuring device, the particle size was less than 200 μm and contained about 3 vol% and less than 262 μm particle size about 16 vol% ( (Average particle size 400 μm). The resin beads were classified as follows using the apparatus shown in FIG.

  20 L of resin beads and 80 L of water were placed in a cylindrical classification tank (570Φ × 700 mmH) having a capacity of 120 L and stirred with an anchor type stirrer (“Three-One Motor”, blade diameter 150 mm) to prepare a classification solution. In this classification tank, a 100 mmΦ × 500 mmH classification tube having a shape as shown in FIG. 2 (four baffles with a width of 20 mm and a height of 100 mm at the liquid inlet and a height of 1.5 mm at a position 300 mm from the liquid inlet. Is inserted into the position of 180 mm from the center of the classification tank and 195 mm from the bottom of the classification tank so that the liquid inlet communicates with the classification liquid, and the liquid flow is continued while stirring at 100 rpm. Suction was performed from the outlet by a pump at a flow rate of 120 L / h (liquid flow rate: 0.00425 m / s). The sucked classification liquid was passed through a cartridge filter (filtration accuracy: 10 μm) to remove contained particles, and the filtrate was again supplied to the classification tank.

  While performing the above classification treatment, the resin was collected from the classification tank every 30 minutes, and the particle size distribution was measured. FIG. 4 shows the relationship between the treatment time and the removal rate of particles having a particle diameter of less than 200 μm. With a treatment time of 2 hours, the removal rate was 98% or more (the content rate of particles having a particle size of less than 200 μm was less than 0.05 vol%), and was not detected after 2.5 hours. The particle yield at this time was 80%.

Example 2
When the classification treatment was performed under the same conditions as in Example 1 except that the classification tube was not provided with ribs, particles having a particle size of less than 200 μm were not detected after 3.0 hours. The particle yield at this time was 75%.

Example 3
When the classification treatment was performed under the same conditions as in Example 1 except that the classification tube was not provided with ribs and baffles, particles with a particle size of less than 200 μm were not detected after 6.0 hours. The particle yield at this time was 50%.

  According to the classification method of the present invention, it is necessary to classify any particulate matter including ceramic porous bodies and resins and porous bodies thereof, and to require a large-sized classification tank having a special structure and a pump with a large flow rate. It is possible to carry out with high efficiency and low cost.

1 Classification tank 2 Classification liquid 3 Stirrer 4 Classification pipe 5 Pump 6 Flow meter 7 Filter 8 Separation tank 21 Liquid inlet 22 Liquid outlet 23 Baffle 24 Rib

Claims (8)

The particles to be classified are added to the classification tank together with the liquid medium, and this is stirred to prepare a classification liquid, and the liquid outlet is connected to the classification liquid in the classification tank so that the liquid inlet communicates with the classification liquid. A cylindrical classification tube having a conical shape is inserted and the classification liquid is sucked from the liquid outlet of the classification pipe while continuing the stirring in the classification tank, so that the liquid is introduced from the liquid inlet. the classification liquid upwardly into the outlet a classifying way to remove fine particles is passed through the classification pipe,
The classifying tube has a plurality of baffles provided evenly at the liquid inlet of the classifying tube and at least one semicircular rib provided above the baffle. Way .   2. The classification method according to claim 1, wherein the classification liquid is sucked at a constant speed capable of separating particles having a particle diameter desired to be separated, which is obtained from a Stokes equation.   The classification method according to claim 1 or 2, wherein the classification target particles are a ceramic porous body, a resin, or a granular material of the porous body. Classification method according to any one of claims 1 to 3 density of the classification target particles wherein there 2,000 Kg / m ³ or less.   The classification method according to claim 1, wherein the liquid medium is water.   The classification method according to any one of claims 1 to 5, wherein a plurality of the classification tubes are used. It is a classification tube used for the classification method as described in any one of Claims 1-6, Comprising: It has the column-shaped shape where the liquid outlet part becomes a cone shape, and is equal to a liquid inlet part. A plurality of baffles provided and at least one semicircular rib provided above the baffle, the baffle having a width of 1/10 or more of the diameter of the classification tube and a length of classifying tube, wherein the at least 1/20 der Turkey classifying tube length. It is a classification tube used for the classification method as described in any one of Claims 1-6, Comprising: It has the column-shaped shape where the liquid outlet part becomes a cone shape, and is equal to a liquid inlet part. provided having a plurality of baffles and at least one semi-circular rib provided on the upper portion than the baffle, the rib is classified tube height, characterized in that a 1 to 10 mm.

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