JP2017213516A - Crystallization classifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crystallization classifier capable of classifying solid particles reaching a predetermined particle diameter and becoming a drawing target with high concentration.SOLUTION: A crystallization classifier includes: a reaction vessel 10 holding a crystallization raw material 110; agitation means 20 provided with a rotation shaft 21 extending in a vertical direction and agitation blades 23 extending from the rotation shaft approximately in a horizontal direction, and rotatably disposed around the center of the reaction vessel; a draft tube 30 disposed so as to surround the periphery of the agitation blades; at least a pair of baffle plates 40 extending along the inner peripheral side surface of the reaction vessel in a vertical direction, projecting toward the rotation shaft, and being disposed so as to sandwich the draft tube from both sides; and a discharge port 51 being disposed at an outer peripheral side from the draft tube and discharging solid particles 111 in the reaction vessel to the outside of the reaction vessel.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a crystallization classifier, and more particularly to a continuous crystallization classifier in which a draft tube is provided in a tank to classify small and large particles.

  Conventionally, the particle size generated in the reaction vessel has been predicted by the reaction rate (growth speed of particle size), the residence time determined by the reaction vessel capacity and the raw material supply speed to the reaction vessel. In this case, although the average particle size can be predicted to some extent, the residence time in the tank varies, so the particle size is also distributed. As a result, particles having a small particle size smaller than the target particle size are also discharged. .

  On the other hand, by providing an inner cylindrical draft tube and a stirrer having necessary power corresponding to the specific gravity and slurry concentration of the slurry below the liquid level in the reaction tank, By flowing upward or downward in the draft tube, particles larger than the target particle size are allowed to settle in the reaction vessel, and by providing an extraction part at the center of the bottom of the reaction vessel, particles larger than a predetermined particle size are provided. There is known a reaction crystallizer capable of discharging only the gas from the reaction tank (for example, see Patent Document 1).

JP-A-10-265225

  However, in the apparatus described in Patent Document 1, the particle size of classified particles has a high ratio of particles other than the desired particle size, and there is a problem in classification efficiency.

  An object of the present invention is to solve the above-mentioned problems, and to provide a crystallization classifier capable of classifying solid particles that have reached a predetermined particle size and have been extracted at a high concentration.

In order to achieve the above object, a crystallization classifying apparatus according to one embodiment of the present invention includes a reaction tank holding a crystallization raw material,
A stirring means comprising a rotary shaft extending in the vertical direction and a stirring blade extending in a substantially horizontal direction from the rotary shaft, the stirring means being rotatably provided near the center of the reaction vessel;
A draft tube provided to surround the periphery of the stirring blade;
At least a pair of baffle plates provided so as to extend in the vertical direction along the inner peripheral side surface of the reaction tank and protrude toward the rotation shaft, and sandwich the draft tube from both sides;
A discharge port that is provided on the outer peripheral side of the draft tube and discharges the solid particles in the reaction tank to the outside of the reaction tank.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to collect | recover the slurry containing the high specific gravity particle | grains which are flowing in the tank bottom with high concentration.

It is the figure which showed an example of the crystallization classification apparatus 100 which concerns on embodiment of this invention. FIG. 1A is a top view of a crystallization classifying apparatus 100 according to an embodiment of the present invention. FIG. 1B is a cross-sectional view taken along the line X-X ′ of FIG. It is the figure which showed the crystallization classification apparatus 101 used for experiment. It is a figure for demonstrating the content of experiment. FIG. 3A is a top view of the crystallization classifier 101. FIG. 3B is a side view of the crystallization classifying apparatus 101. It is the figure which showed the result of the average density | concentration which sampled 3 times. FIG. 4A shows the density distribution at the sampling position A shown in FIG. FIG. 4B is a diagram showing the density distribution at the sampling position B shown in FIG. FIG. 4C is a diagram showing the density distribution at the sampling position C shown in FIG. It is the figure which showed the density distribution of the tank bottom in experiment conditions. It is the figure which showed the example of the location suitable for slurry extraction. FIG. 6A is a top view of an example of a portion suitable for slurry extraction. FIG.6 (b) is a side view of the example of a suitable location for slurry extraction.

  The present inventor has found that depending on the shape of the reaction vessel and the configuration and arrangement of the draft tube, particles having a particle size larger than the target particle size are not necessarily collected at the center of the reaction vessel.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing an example of a crystallization classification apparatus 100 according to an embodiment of the present invention. FIG. 1A is a top view of a crystallization classifying apparatus 100 according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along the line X-X ′ of FIG.

  As shown in FIGS. 1 (a) and 1 (b), a crystallization classifier 100 according to an embodiment of the present invention includes a reaction vessel 10, a stirrer 20, a draft tube 30, a baffle plate 40, and an extraction plate. It has a pipe 50, a crystallization raw material supplier 60, and a pump 70. Note that the lower end of the extraction pipe 50 constitutes a discharge port 51. Further, the baffle plate 40 is not shown in FIG. 1B because it is not on the X-X ′ cross section in FIG.

  In general, a classification outlet for extracting a slurry of large-diameter particles is provided by forming a hole in the center of the bottom surface of the reaction vessel 10, and is often configured to extract large-diameter particles from below. However, in the present embodiment, the discharge port 51 is provided outside the draft tube 30. Further, although it is not essential to extract the large-diameter particles from above, the large-diameter solid particles 111 existing on the bottom surface of the reaction vessel 10 outside the draft tube 30 are extracted from the bottom of the reaction vessel 10 with the lower discharge port 51. It is set as the structure extracted through the piping-shaped extraction piping 50 provided in the vicinity. Such a configuration is a configuration derived from experimental support, and is based on an experimental result that the solid particles 111 are likely to be deposited outside the reaction vessel 10. The details of the experimental results will be described later. First, individual components of the crystallization classification apparatus 100 according to the present embodiment will be described.

  The reaction tank 10 is a means for holding the crystallization raw material 110 in the tank, and is a means for stirring and causing the crystallization raw material 110 held in the tank to generate and accelerate the crystallization reaction. The crystallization raw material 110 is in a liquid state or a slurry state composed of liquid and fine particles when the raw material is charged, but as the crystallization reaction proceeds, solid particles 111 are generated and the particle size of the solid particles 111 increases. Go. Therefore, the reaction tank 10 normally holds the crystallization raw material 110 in which the liquid and the solid particles 111 are mixed in the tank.

  The reaction vessel 10 is preferably configured in a cylindrical shape having a mirror bottom. By having the said shape, it becomes easy to form the circulation flow which circulates up and down. A specific description of the circulation flow will be described later.

  As the crystallization raw material 110, various raw materials may be selected according to the crystallization target and application, but for example, the crystallization raw material 110 for crystallizing the Ni solid particles 111 may be used.

  The stirrer 20 is a stirring means for stirring the crystallization raw material 110 in the reaction vessel 10. The stirrer 20 includes a rotating shaft 21, a stirring blade support part 22, a stirring blade 23, and a motor 24. The rotating shaft 21 may be provided at an arbitrary position in the reaction vessel 10, but is generally provided near the center of the reaction vessel 10, and preferably provided so as to coincide with the center of the reaction vessel 10. In other words, the agitating blade 23 is installed so that a symmetrical flow can be generated in the reaction vessel 10 about the rotation axis. The rotating shaft 21 extends in the vertical direction and rotates the stirring blade 23 horizontally.

  The stirring blade support portion 22 is a support means for supporting the stirring blade 23. The stirring blade support 22 is fixed to the rotating shaft 21 and plays a role of transmitting the rotation of the rotating shaft 21 to the stirring blade 23.

  The stirring blade 23 may be configured to have various shapes depending on the application. For example, the stirring blade 23 has an inclination with respect to the horizontal direction or the vertical direction in order to form a vertical flow of the crystallization raw material 110. Propeller-type or inclined paddle-type stirring blades 23 are preferably used. By being provided with an inclination, it is possible to form a vertical flow that extrudes the crystallization raw material 110 up and down.

  The stirring blade 23 preferably has a shape extending in the horizontal direction (left-right direction) around the rotation shaft 21. Thereby, the rotation of the rotating shaft 21 can be efficiently transmitted to the crystallization raw material 110 without loss, and a flow symmetrical to the rotating shaft 21 can be formed.

  One or more stirring blades 23 are provided around the stirring blade support 22. When the number of stirring blades 23 extending left and right around the rotating shaft 21 is counted as one, at least one stirring blade 23 is provided, and circulation in the reaction tank 10 is further performed according to the application and the length of the reaction tank 10. A plurality may be provided to the extent that the flow can be maintained. In the present embodiment, the stirring blades 23 are configured as inclined stirring paddles in both the upper stage and the lower stage, and are provided in pairs around the stirring blade support member 22 (see FIG. 2). 1 (a)).

  The motor 24 is a driving means for rotating the stirring blade 23 via the stirring blade support portion 22, and various motors 24 may be used as long as the stirring blade 23 can be rotated at an appropriate speed and torque. .

  The draft tube 30 is provided to adjust the flow in the stirring tank 10 and functions as a rectifying member. The draft tube 30 has a cylindrical shape and is provided so as to surround the periphery of the stirring blade 23. The draft tube 30 serves to form an upward flow in the draft tube 30 by causing the upward flow of the crystallization raw material 110 formed by the stirring blade 23 to follow the inner peripheral surface thereof.

  The draft tube 30 is provided so as to be supported upright on the axial center in the reaction vessel 10. The draft tube 30 has a cylindrical shape and is provided so as to cover the stirring blade 23 at a predetermined interval from the tip of the stirring blade 23. By installing the draft tube 30, the rectification effect in the reaction vessel 10 and the reduction of the agitator power by rectification are expected.

  In addition, the draft tube 30 can be comprised with various materials, for example, may be comprised from stainless steel.

  The baffle plates 40 are provided so as to sandwich the draft tube 30 from both sides, that is, in pairs. In other words, one or more baffle plates 40 are installed radially so as to protrude toward the axial center of the reaction vessel 10. For example, only one pair of baffle plates 40 may be provided so as to sandwich the draft tube 30 from the left and right, or two pairs may be provided so as to sandwich the draft tube 30 from four directions. Or more may be provided as needed. Thus, the number of baffle plates 40 may be appropriately determined according to the application. In the present embodiment, as shown in FIG. 1A, an example will be described in which two baffle plates 40 are arranged in a cross shape. The baffle plate 40 may be referred to as a baffle 40.

  The extraction pipe 50 is a means for extracting the slurry containing the solid particles 111 deposited on the bottom surface of the reaction tank 10 to the outside of the reaction tank 10. In the classification crystallizer according to the present embodiment, the extraction pipe 50 is configured as a pipe extending in the vertical direction along the inner peripheral surface of the reaction tank 10. The lower end portion of the extraction pipe 50 functions as a discharge port 51 in order to extract the slurry containing the solid particles 111 deposited on the bottom surface of the reaction tank 10 and discharge it to the outside of the reaction tank 10. That is, the lower end of the extraction pipe 50 functions as a suction port for the slurry containing the solid particles 111. Therefore, although the discharge port 51 is provided above the bottom surface of the reaction tank 10, if it is too far from the bottom surface, it becomes difficult to suck the solid particles 111, so that the solid particles 111 can be sucked efficiently. Provided in the vicinity of the bottom surface. For example, you may make it provide the discharge port 51 in the range of 2 mm-5 cm from the bottom face of the reaction tank 10. FIG. The discharge port 51 may be provided so as to be in contact with the bottom surface of the reaction tank 10, but may block the discharge port 51 and narrow the range in which the solid particles 111 can be sucked. It is preferable to be provided near the bottom surface above the bottom surface.

  Since the extraction pipe 50 enables extraction of the slurry containing the solid particles 111 above the reaction tank 10, the extraction pipe 50 has at least a portion configured higher than the liquid surface of the crystal precipitation raw material 110. Preferably, a portion configured higher than the upper end of the reaction vessel 10 is included. Further, the end of the extraction pipe 50 provided above the reaction tank 10 is connected to a pump 70 so that the slurry containing the solid particles 111 can be pumped from the bottom surface of the reaction tank 10.

  As shown in FIGS. 1A and 1B, the extraction pipe 50 and the discharge port 51 are provided on the outer peripheral side of the draft tube 30. This is because in the crystallization classification apparatus 100 according to the present embodiment, the concentration of the solid particles 111 is higher on the outside than the inside of the draft tube 30, and a large amount of the solid particles 111 are deposited.

  The extraction pipe 50 and the discharge port 51 may be provided at various positions as long as they are outside of the draft tube 30. For example, the radius between the outer peripheral surface of the draft tube 30 and the inner peripheral surface of the reaction vessel 10. You may make it provide in the outer peripheral side rather than the intermediate point in a direction, or an intermediate point. Although details will be described later using experimental data, an intermediate point in the radial direction between the outer peripheral surface of the draft tube 30 and the inner peripheral surface of the reaction vessel 10, or the outer peripheral side of the intermediate point is more than the intermediate point. Since the result that the density | concentration of the solid particle 111 is higher than the inner area | region is obtained, the extraction piping 50 and the discharge port 51 are the radii between the outer peripheral surface of the draft tube 30, and the internal peripheral surface of the reaction tank 10. It is more preferable to arrange at an intermediate point in the direction or outside the intermediate point.

  As shown in FIG. 1A, the extraction pipe 50 and the discharge port 51 may be provided at an intermediate point in the circumferential direction between the adjacent baffle plates 40a and 40b. In FIG. 1A, an extraction pipe 50 is provided at an intermediate point (on XX ′) in the circumferential direction between the baffle plate 40a on the right rear side and the baffle plate 40b on the right front side of the two pairs of baffle plates 40. Is provided. Although this point will also be described later using experimental data, the result that the concentration of the solid particles 111 is higher than that of other regions on the intermediate point in the circumferential direction between the adjacent baffle plates 40a and 40b is obtained. Therefore, by providing the extraction pipe 50 on the intermediate point between the baffle plates 40a and 40b where more solid particles 111 are likely to be deposited, it is possible to extract the high-concentration solid particles 111.

  In the experiment described later, the result that the concentration of the solid particles 111 is high on the intermediate point between the adjacent baffle plates 40a and 40b is obtained. Even if it is slightly off in the direction, if it is close to the middle point, the concentration of the solid particles 111 should still be high. Therefore, for example, the region between the adjacent baffle plates 40a and 40b is divided into three equal parts in the circumferential direction so that each of them forms a fan shape, and the middle (center) region including the middle point in the circumferential direction is divided into one third of the region. By arranging the extraction pipe 50, it is possible to obtain the effect of the crystallization classification apparatus 100 according to the embodiment of the present invention for extracting the high concentration solid particles 111. Similarly, the discharge port 51 of the extraction pipe 50 may be provided in a 1/5 region including an intermediate point in the circumferential direction, may be provided in a 1/7 region, or 1/9. It may be provided in the area. Since the position of the discharge port 51 is preferably closer to the intermediate point in the circumferential direction, the solid particles 111 can be extracted at a higher concentration as the range of the region is narrower.

  The crystallization raw material charging device 60 is a means for charging the crystallization raw material 110 into the reaction tank 10, and includes a crystallization raw material tank 61 and a crystallization raw material charging port 62. The crystallization raw material tank 61 is a tank for accumulating the crystallization raw material 110, and stores, for example, a slurry-like crystallization raw material 110. The crystallization raw material charging port 62 is a raw material charging port or a raw material supply port for charging or supplying the crystallization raw material 110 accumulated in the crystallization raw material tank 61 into the reaction tank 10.

  As described above, according to the crystallization classification apparatus 100 according to the present embodiment, the slurry containing the high-concentration solid particles 111 is added to the reaction tank by providing the extraction pipe 50 and the discharge port 51 on the outside of the draft tube 30. 10 can be extracted. In addition, preferably, the extraction pipe 50 and the discharge port 51 are arranged at an intermediate point in the radial direction between the outer peripheral surface of the draft tube 30 and the inner peripheral surface of the reaction tank 10, or on the outer peripheral side of the intermediate point, and more preferably. By providing at the intermediate point in the circumferential direction between the adjacent baffle plates 40a, 40b, the slurry containing the high-concentration solid particles 111 can be more reliably extracted from the reaction vessel 10.

  In addition, in FIG. 1, although the example which extracts the slurry containing the solid particle 111 using the extraction piping 50 is given and demonstrated, the hole is formed in the bottom face of the reaction tank 10 of the same location, and the discharge port 51 is set. It is also possible to provide it. When the discharge port 51 is provided at the bottom of the reaction tank 10, the flow path is cut off by a valve or the like during the time when the extraction is not performed, but particles may be deposited and blocked in the vertical portion of the extraction portion. However, it is possible to extract the slurry containing the solid particles 111 from below the reaction vessel 10 by taking measures such as increasing the diameter of the discharge port 51. Therefore, it is not essential to provide the extraction pipe 50, and it may be provided as necessary.

  On the other hand, like the crystallization classifier 100 shown in FIG. 1, by carrying out slurry extraction with the extraction pipe 50, when the extraction is interrupted, the solid particles 111 are settled within the extraction pipe 50, and the reaction tank 10 Returning the solid particles 111 to this has the advantage that the blockage of the extraction pipe 50 can be eliminated.

[Experimental result]
Next, experimental data supporting the effectiveness of the crystallization classifying apparatus 100 according to the above-described embodiment will be described.

  FIG. 2 is a diagram showing the crystallization classifier 101 used in the experiment. The crystallization classification apparatus 101 shown in FIG. 2 is slightly different from the crystallization classification apparatus 100 shown in FIG. 1 in shape and the like, but the basic configuration is the same as that of the crystallization classification apparatus 100 shown in FIG. Constituent elements are denoted by the same reference numerals and description thereof is omitted.

  The crystallization classifying apparatus 101 according to FIG. 2 is different from the crystallization classifying apparatus 100 according to FIG. 1 in that the extraction pipe 50 is not provided, but these affect the experimental results. Not a difference.

  A crystallization reaction was performed using the crystallization classifier 101, and the slurry concentrations at a plurality of points were measured. The experimental conditions were such that particles having a small particle diameter of 32 to 53 μm were used, the slurry concentration was 200 g / L, a two-stage stirring blade 23 having a width of 25 mm and a diameter (blade length) of 170 mm, and a rotational speed. Rotated at 600 rpm. The draft tube 30 was installed at a position 56 mm from the tank bottom.

  FIG. 3 is a diagram for explaining the contents of the experiment. 3A is a top view of the crystallization classifying apparatus 101, and FIG. 3B is a side view of the crystallization classifying apparatus 101.

  As shown in FIG. 3A, the stirrer blade 23 of the stirrer 20 is rotated in the counterclockwise direction, and the position immediately downstream of the baffle plate 40c is the sampling position A, and the midpoint between the baffle plate 40c and the baffle plate 40d. Is the sampling position B, and the position immediately upstream of the baffle plate 40d is the sampling position C. For each sampling position A, B, C, the slurry concentration of the crystallization raw material 110 and the solid particles 111 at 17 positions shown in FIG. Was measured.

  In addition, the measurement point is a point 50 mm outside the rotary shaft 21 from the inside, a point on the inner wall and the outer wall of the draft tube 30, an intermediate point between the outer wall of the draft tube 30 and the inner wall of the reaction tank 10, and a tank wall of the reaction tank 10. It is. Further, the depth is each point of −50 mm, −150 mm, −250 mm, −350 mm, −300 mm, and −400 mm with reference to the liquid surface of the crystallization raw material 110.

  FIG. 4 shows the result of the average density obtained by sampling three times. 4A shows the concentration distribution at the sampling position A shown in FIG. 3A, FIG. 4B shows the concentration distribution at the sampling position B shown in FIG. 3A, and FIG. FIG. 4 is a diagram showing density distributions at sampling positions C shown in FIG. The concentration of the slurry was divided into four levels: a concentration of 200 g / L or more, a concentration in the range of 180 to 200 g / L, a concentration of 140 to 180 g / L, and a concentration of less than 140 g / L.

  As a result, as shown particularly prominently in FIGS. 4 (a) and 4 (b), an intermediate point between the outer wall of the draft tube 30 near the bottom of the reaction tank 10 and the inner wall of the reaction tank 10 or slightly outside of the intermediate wall. The result was that the sampling concentration at the location was high on average.

  Next, in the same crystallization classifier 101, the slurry concentration of the crystallization raw material 110 is 200 g / L, the small particle size slurry of 32 to 53 μm is 100 g / L, and the large particle size slurry of 106 to 250 μm is 100 g / L. The mixing ratio was used. The rotation speed of the stirrer 20 was set to 500 rpm.

  FIG. 5 is a diagram showing the concentration distribution at the bottom of the tank under such experimental conditions. As shown in FIG. 5, when compared in the radial direction, the density is high on average at the two outer positions in any of the sampling positions A, B, and C. Further, when compared in the circumferential direction, the sampling position B, that is, the position B in the middle of the baffle plate 40d, is generally higher in density than the sampling positions A and C.

  Therefore, the slurry concentration is higher in the radial direction than the draft tube 30, and preferably in the middle of the draft tube 30 and the reaction vessel 10, or in the position outside thereof, and is adjacent in the circumferential direction. Experiments have shown that the slurry concentration at the intermediate position between the baffle plate 40c and the baffle plate 40d is high. Therefore, it is preferable to extract the slurry containing the solid particles 111 at a position corresponding to this.

  FIG. 6 is a diagram showing an example of a portion suitable for such slurry extraction. FIG. 6A is a top view of an example of a location suitable for slurry extraction, and FIG. 6B is a side view of an example of a location suitable for slurry extraction.

  As shown in FIGS. 6A and 6B, the sampling position B, that is, near the middle between the adjacent baffle plate 40 c and the baffle plate 40 d, near the tank bottom outside the draft tube 30. Is preferred.

  This point is consistent with the crystallization classification apparatus 100 according to the present embodiment shown in FIG. 1, and the crystallization classification apparatus 100 according to the present embodiment has a configuration based on these experimental results.

  Thus, according to the crystallization classifier according to the embodiment of the present invention, the slurry containing a large amount of large-diameter particles flowing at the bottom of the reaction vessel is outside the draft tube, for example, at the center of the baffle plate and the baffle plate. It is pulled out of the tank via a pipe provided at a position near the bottom of the tank. By performing the extraction with the downward piping, when the extraction is interrupted, the particles settle in the downward piping and return the particles to the reaction tank, thereby eliminating the blockage of the extraction piping. In addition, the stirring blades are rotating in the draft tube, and it is impossible to hang down the extraction pipe, and it has been confirmed by experiments that the slurry concentration is reduced near the baffle plate due to the mixing promotion effect of the baffle plate. The piping position was determined and set as the position outside the draft tube as described above.

  Thereby, it becomes possible to collect | recover the slurry containing the high specific gravity particle | grains which are flowing at the tank bottom with high concentration. Moreover, the piping blockage at the time of withdrawal interruption can be solved.

  In addition, in this embodiment, although the example in which two pairs of baffle plates 40 are provided has been described, even in the case of a pair or more than two pairs, the outer side of the draft tube 30, In addition, by providing the discharge port 51 in the vicinity of the intermediate point between the adjacent baffle plates 40, a high-concentration slurry can be collected.

  The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. Can be added.

DESCRIPTION OF SYMBOLS 10 Reaction tank 20 Stirrer 21 Rotating shaft 22 Stirring blade support part 23 Stirring blade 24 Motor 30 Draft tube 40, 40a-40d Baffle 50 Extraction pipe 51 Discharge port 60 Crystallization raw material supply device 61 Crystallization raw material tank 62 Crystallization raw material Input port 70 Pump 100, 101 Crystallization classifier 110 Crystallization raw material 111 Solid particles

Claims (8)

A reaction vessel holding the crystallization raw material,
A stirring means comprising a rotary shaft extending in the vertical direction and a stirring blade extending in a substantially horizontal direction from the rotary shaft, the stirring means being rotatably provided near the center of the reaction vessel;
A draft tube provided to surround the periphery of the stirring blade;
At least a pair of baffle plates provided so as to extend in the vertical direction along the inner peripheral side surface of the reaction tank and protrude toward the rotation shaft, and sandwich the draft tube from both sides;
A crystallization classifier having a discharge port provided on the outer peripheral side of the draft tube and discharging solid particles in the reaction tank to the outside of the reaction tank.   2. The crystallization classification according to claim 1, wherein the discharge port is provided on an intermediate point in the radial direction between the outer peripheral surface of the draft tube and the inner peripheral surface of the reaction tank, or on the outer side of the intermediate point. apparatus.   The discharge port is provided in a middle region including an intermediate point in the circumferential direction when a region between the baffle plates arranged adjacent to each other is equally divided into three in the circumferential direction. 2. The crystallization classifier according to 2.   The crystallization classifier according to claim 3, wherein the discharge port is provided on the intermediate point in the circumferential direction between the baffle plates arranged adjacent to each other.   The crystallization classifying apparatus according to any one of claims 1 to 4, wherein the baffle plates are provided in two pairs in a cross shape.   The discharge port includes a portion that extends in the vertical direction along the inner peripheral surface of the reaction tank and that is provided above the upper end of the reaction tank so that the solid particles can be extracted above the reaction tank. The crystallization classification apparatus according to any one of claims 1 to 5, which is a lower end of a pipe.   The crystallization classifier according to claim 6, wherein the lower end of the pipe is provided in the vicinity of the bottom surface of the reaction tank.   The crystallization classification apparatus according to any one of claims 1 to 7, wherein a crystallization raw material inlet for supplying the crystallization raw material to the reaction vessel is provided.

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