JP2024047578A - Metal compound fine particle manufacturing device, metal compound fine particle manufacturing system - Google Patents

Abstract

[Problem] To provide an apparatus for producing fine particles of a metal compound having high sphericity, a high nickel content of 90% or more in terms of substance amount ratio, and an average particle diameter d50 of 3 μm or less. [Solution] An apparatus for producing fine particles of a metal compound, comprising: an agitator blade having a plurality of holes passing through in the radial direction and capable of rotating around a central axis, a cylindrical reaction vessel with a bottom capable of concentrically accommodating the agitator blade inside, a first liquid supply unit provided in the reaction vessel and capable of supplying a first reaction liquid to the inside of the reaction vessel, a second liquid supply unit provided in the agitator blade and capable of supplying a second reaction liquid to the inside of the reaction vessel, and a control unit for controlling the peripheral speed of the agitator blade. [Selected Figure] Figure 1

Description

The present invention relates to an apparatus for producing fine particles of metal compounds and a system for producing fine particles of metal compounds.

There is a demand for higher capacity and power output in cathode materials for next-generation batteries, such as high-performance secondary batteries and all-solid-state batteries.

In order to achieve high capacity and high output, research is being conducted to increase the nickel content in the positive electrode material and to reduce the particle size (secondary particle size).

The co-precipitation method is commonly used to manufacture metal hydroxides, which are the raw material for cathode materials. The more the nickel content in the metal hydroxide is increased to increase the capacity of the cathode material, the larger the particle size of the metal hydroxide obtained by the co-precipitation method tends to become, which conflicts with the need for microparticulation to obtain high output. In order to achieve both high capacity and high output, research is being conducted into technology that can increase the nickel content and produce microparticulate material.

Methods for achieving high nickel content and fine particle size include shortening the residence time of the crystals in the reaction tank and increasing the pH. This makes it possible to reduce the secondary particle size, but excessive shortening of the residence time or high pH leads to a decrease in crystal quality, such as miniaturization of primary particles and deterioration of the shape of secondary particles (reduced sphericity), and the limit of maintaining crystal quality is the limit of adjustment using the above methods. Here, sphericity is defined as (diameter equivalent to the area circle of the projected image of the particle) / (diameter of the smallest circumscribed circle of the projected image of the particle).

Research has been conducted into suppressing particle size growth by increasing the stirring and shearing forces in the reaction apparatus, but there is a need to transmit high stirring and shearing forces with high efficiency to the micro-reaction field of metal hydroxides, which have very short reaction times. In particular, when producing ultrafine particles with an average particle size d50 of 3 μm or less from metal hydroxides with a high nickel content, the challenge in increasing sphericity is to transmit high stirring and shearing forces with high efficiency to the micro-reaction field.

Patent Document 1 discloses a manufacturing apparatus that is equipped with a pump and a propeller-type rotor-type agitator, and that manufactures a positive electrode active material for a non-aqueous electrolyte secondary battery having an average particle size of 1.00 μm to 3.0 μm and a nickel content of up to 80%.
Patent Document 2 discloses a production apparatus equipped with a turbine impeller as an agitator for producing an oxide-based positive electrode active material for an all-solid-state lithium-ion battery having an average particle diameter d50 of 1.0 to 5.0 μm.
Patent Document 3 discloses an apparatus for producing ternary oxide microparticles composed of cerium, zirconium, and yttrium, the primary particles having an average particle size of 0.5 to 100 nm and the secondary particles having an average particle size of 2 to 100 nm.

Republished WO2019/117027 International Publication No. 2020/202602 Patent No. 4784623

The present invention has been made against this background, and aims to provide a manufacturing device for metal compound fine particles that can realize high capacity and high output to the extent that they can be used as positive electrode materials for next-generation batteries, and that can control the average particle diameter d50 of metal compound fine particles with a high nickel content mainly by adjusting the peripheral speed of the stirring blade.

In order to solve the above problems and achieve the above object, the present invention proposes the following means.
A first aspect of the present invention is an apparatus for producing fine particles of a metal compound, comprising: an agitator having a plurality of holes penetrating in the radial direction and capable of rotatable around a central axis; a bottomed cylindrical reaction vessel capable of concentrically accommodating the agitator therein; a first liquid supply section provided in the reaction vessel and capable of supplying a first reaction liquid to the inside of the reaction vessel; a second liquid supply section provided in the agitator and capable of supplying a second reaction liquid to the inside of the reaction vessel; and a control section for controlling the peripheral speed of the agitator.

According to the first aspect of the present invention, a manufacturing device for producing fine particles of a metal compound can be obtained in which the average particle diameter d50 of a metal compound having high sphericity can be controlled mainly by adjusting the peripheral speed of the stirring blade. That is, a control unit capable of controlling the peripheral speed of the stirring blade is provided, and the shear force and the circulating flow can be adjusted separately, so that stirring specialized for the transmission of shear force is possible in the reaction tank. The great advantage of this mechanism improvement is that the particle diameter can be controlled mainly by adjusting the peripheral speed of the stirring blade. Since the particle diameter can be controlled mainly by adjusting the peripheral speed of the stirring blade while the set values of the residence time and pH value remain constant under conditions that do not deteriorate the product quality, the control performance of the particle diameter is dramatically improved. This improvement in functionality makes it possible to control the particle diameter while maintaining the residence time and pH value that do not cause deterioration of the particle shape, and to obtain a high-quality metal hydroxide with a high nickel content and a small average particle diameter and high sphericity.

The second aspect of the present invention is an apparatus for producing fine particles of a metal compound, characterized in that in the first aspect, the stirring blade of the crystallization device comprises a cylindrical portion having the plurality of holes penetrating in the radial direction, a disk-shaped disk portion having an outer periphery fixed to the inner circumferential surface of the cylindrical portion, and a rotating shaft extending upward from the center of the disk portion along the central axis in a plan view, the second reaction liquid can flow through the inside of the disk portion and the rotating shaft, and the second liquid supply portion is provided on the outer periphery of the disk portion.

According to the second aspect of the present invention, it is possible to obtain a manufacturing device for producing fine particles of a metal compound, which can supply the second reaction liquid to a range close to the inner and outer periphery of the stirring blade where the shear force is high, and the average particle diameter d50 of the metal compound having high sphericity can be controlled mainly by adjusting the peripheral speed of the stirring blade.

The third aspect of the present invention is a manufacturing device for metal compound microparticles, which is the second aspect, characterized in that the second liquid supply section opens downward.

According to the third aspect of the present invention, it is possible to obtain a manufacturing device for metal compound fine particles, which can supply the second reaction liquid to a range close to the inner and outer periphery of the stirring blade where the shear force is high, and can control the average particle diameter d50 of the metal compound with high sphericity mainly by adjusting the peripheral speed of the stirring blade.

The fourth aspect of the present invention is an apparatus for producing fine particles of a metal compound according to the third aspect, characterized in that in the cylindrical portion above the disk portion, a plurality of holes penetrating in the radial direction are blocked, and a disk-shaped second disk portion having an outer periphery fixed to the inner circumferential surface of the cylindrical portion is provided at the upper end of the cylindrical portion.

According to the fourth aspect of the present invention, it is possible to obtain a manufacturing device for producing fine particles of metal compounds, which reduces the power required to rotate the stirring blades and allows the average particle diameter d50 of metal compounds with high sphericity to be controlled mainly by adjusting the peripheral speed of the stirring blades.

The fifth aspect of the present invention is the third aspect of the apparatus for producing fine particles of a metal compound, characterized in that the disk portion is provided at the upper end of the cylindrical portion.

According to the fifth aspect of the present invention, it is possible to obtain a manufacturing device for producing fine particles of a metal compound, which reduces the power required to rotate the stirring blade and allows the average particle diameter d50 of a metal compound with high sphericity to be controlled mainly by adjusting the peripheral speed of the stirring blade.

The sixth aspect of the present invention is an apparatus for producing fine particles of a metal compound according to any one of the second to fifth aspects, characterized in that, when the clearance between the outer peripheral surface of the cylindrical portion and the inner peripheral surface of the reaction tank is L3 and the height of the cylindrical portion is He, He/L3 is 10 or more.

According to the sixth aspect of the present invention, it is possible to obtain a manufacturing device for fine particles of a metal compound, in which the average particle diameter d50 of the metal compound having high sphericity can be controlled mainly by adjusting the peripheral speed of the stirring blade.

The seventh aspect of the present invention is an apparatus for producing fine particles of a metal compound according to any one of the first to sixth aspects, characterized in that a plurality of the second liquid supply sections are provided.

According to the seventh aspect of the present invention, it is possible to obtain a manufacturing device for producing fine particles of a metal compound, which can supply the second reaction liquid uniformly in the circumferential direction of the disk portion, and in which the average particle diameter d50 of a metal compound having high sphericity can be controlled mainly by adjusting the peripheral speed of the stirring blade.

The eighth aspect of the present invention is a system for producing fine particles of a metal compound, comprising the manufacturing apparatus according to any one of the first to seventh aspects, a circulation line for flowing a slurry containing the fine particles discharged from an outlet of the manufacturing apparatus and circulating the slurry from the first liquid supply section of the manufacturing apparatus into the manufacturing apparatus, and a circulation pump for circulating the slurry between the manufacturing apparatus and the circulation line, the circulation line having a bent portion forming a serpentine shape.

According to the eighth aspect of the present invention, a production system for fine particles of metal compounds can be obtained in which the average particle diameter d50 of metal compounds with high sphericity can be controlled mainly by adjusting the peripheral speed of the stirring blades.

The ninth aspect of the present invention is an apparatus for producing fine particles of a metal compound, characterized in that in the first aspect, the stirring blade comprises a cylindrical cylinder portion having the plurality of holes penetrating in the radial direction, a disk-shaped disk portion whose outer periphery is fixed to the inner circumferential surface of the cylindrical portion, and a rotating shaft extending upward from the center of the disk portion along the central axis in a plan view, a through hole penetrating the disk portion in the direction of extension of the rotating shaft is provided on the radial outer side of the disk portion, the second liquid supply portion is provided at two different locations in the direction of extension of the rotating shaft, the upper second liquid supply portion provided on the upper side is provided on the outer periphery of the disk portion, and the lower second liquid supply portion provided on the lower side is provided on an extension portion extending radially outward from the lower part of the rotating shaft, and the second reaction liquid can flow through the inside of the rotating shaft, the disk portion, and the extension portion.

According to the ninth aspect of the present invention, the second liquid supply section for supplying the second reaction liquid is provided at two different locations in the direction in which the rotation shaft extends, so that the first reaction liquid and the second reaction liquid are mixed more effectively. In addition, a through hole is provided through the disk section in the direction in which the rotation shaft extends, so that the flow of the mixed liquid in the reaction tank becomes smoother and pressure loss can be reduced. In other words, the flow resistance of the reaction tank to the flow of the mixed liquid can be reduced, so that pressure loss in the reaction tank can be reduced. Therefore, the power consumption of the pump can be suppressed when increasing the circulation flow rate.

The tenth aspect of the present invention is the apparatus for producing fine particles of a metal compound according to the ninth aspect, characterized in that the outlet of the reaction vessel is open in the direction in which the rotation shaft extends in the reaction vessel.

According to the tenth aspect of the present invention, an increase in the peripheral speed of the stirring blade does not directly lead to an increase in the circulation flow rate of the mixed liquid from the first liquid supply section (inlet) to the outlet. In other words, an increase in the peripheral speed of the stirring blade increases only the shear force acting on the mixed liquid, and the increase in the circulation flow rate of the mixed liquid from the inlet to the outlet can be made to depend only on the flow rate of the pump installed outside the manufacturing apparatus. Therefore, it is possible to individually control with higher precision the circulation flow rate of the mixed liquid in the manufacturing apparatus and the increase or decrease in the shear force acting on the mixed liquid due to the increase or decrease in the peripheral speed of the stirring blade. Therefore, it is possible to control the properties of the generated particles with higher precision.

The eleventh aspect of the present invention is a system for producing fine particles of a metal compound, comprising the production apparatus of the tenth aspect, a circulation line for flowing a slurry containing the fine particles discharged from the discharge port of the production apparatus and circulating the slurry from the first liquid supply unit of the production apparatus into the production apparatus, and a circulation pump for circulating the slurry between the production apparatus and the circulation line, the circulation line including a retention tank.

According to the eleventh aspect of the present invention, by providing a retention tank, the reaction time and retention time required for generating the microparticles can be appropriately adjusted to obtain the desired microparticles.

The twelfth aspect of the present invention is a system for producing fine particles of a metal compound, comprising the production apparatus of the tenth aspect, a circulation line for flowing a slurry containing the fine particles discharged from the discharge port of the production apparatus and circulating the slurry from the first liquid supply unit of the production apparatus into the production apparatus, and a circulation pump for circulating the slurry between the production apparatus and the circulation line, wherein the circulation line does not include a retention tank.

According to the twelfth aspect of the present invention, by not including a retention tank, the microparticle production system can have a completely sealed structure. Therefore, since the production apparatus can be operated under pressure, it is possible to suppress the occurrence of cavitation caused by the mixed liquid becoming equal to or lower than the saturated vapor pressure in the low pressure region generated by the rotation of the stirring blade, and it is also possible to suppress the occurrence of cavitation even under high temperature conditions where the saturated vapor pressure increases.

The thirteenth aspect of the present invention is the system for producing fine particles of a metal compound according to the eleventh or twelfth aspect, characterized in that the second liquid supply part capable of supplying the second reaction liquid to the inside of the reaction tank is further provided above the stirring blade and the first liquid supply part in the reaction tank.

According to the thirteenth aspect of the present invention, the shear force acting on the mixed liquid in the region above the stirring blade and the region below the stirring blade can be individually controlled. Therefore, it is possible to improve the adjustment function of not only the crystal particle size but also the crystal shape. Furthermore, since the number of places to supply the second reaction liquid is increased, the dispersibility of the mixed liquid is improved, and the production capacity of fine particles can be improved. In addition, the second reaction liquid can be divided into a system that supplies the upper second liquid supply part and the lower second liquid supply part, and a system that supplies the second reaction liquid to the upper side of the stirring blade and the first liquid supply part in the reaction tank. Therefore, by supplying the main raw material to one system and supplying a different additive that contributes to improving the quality of the crystal product to the other system, it is possible to shorten the additive addition process and produce a product containing the additive as an ingredient.

The present invention provides a manufacturing device for metal compound microparticles that can achieve high capacity and high output to the extent that they can be used as positive electrode materials for next-generation batteries, and that can control the average particle diameter d50 of metal compound microparticles with a high nickel content mainly by adjusting the peripheral speed of the stirring blade.

1 is a schematic diagram of a crystallization system according to a first embodiment of the present invention. FIG. 1 is an enlarged view of a main part of a crystallization system according to a first embodiment of the present invention. FIG. 1 is a graph showing the relationship between the average particle size of fine particles produced using the crystallization system of the first embodiment according to the present invention and the peripheral speed of the stirring blade. 1 is a photograph of fine particles produced using the crystallization system of the first embodiment according to the present invention. 1 is a photograph of microparticles produced using a prior art crystallization system. 4 is a photograph of microparticles produced using the second or third modified example of the crystallization system of the first embodiment according to the present invention. FIG. 1 is a schematic diagram of a crystallization system according to a first modified example of a first embodiment of the present invention. FIG. 2 is a schematic diagram of a crystallization system according to a second modified example of the first embodiment of the present invention. FIG. 1 is a schematic diagram of a crystallization system according to a third modified example of the first embodiment of the present invention. FIG. 2 is a schematic diagram of a crystallizer in a crystallization system according to a second embodiment of the present invention. FIG. 11 is a schematic diagram of a modified example of a crystallizer in the crystallization system according to the second embodiment of the present invention. FIG. 2 is a cross-sectional view of a crystallizer in a crystallization system according to a second embodiment of the present invention. FIG. 2 is a schematic diagram of a crystallization system according to a second embodiment of the present invention. FIG. 1 is a schematic diagram of a first modified example of a crystallization system according to a second embodiment of the present invention. FIG. 11 is a schematic diagram of a second modified example of the crystallization system according to the second embodiment of the present invention.

First Embodiment
Hereinafter, a crystallization system 10A according to a first embodiment of the present invention will be described with reference to FIG.

The crystallization system 10A includes a crystallizer 4 that mixes multiple raw material solutions to generate particles derived from the raw materials in the multiple raw material solutions, a circulation line Po that is provided downstream of the crystallizer 4 and circulates the slurry D1 discharged from the discharge port 6 of the crystallizer 4 to the inlet (first liquid supply section) 5a of the crystallizer 4, and a circulation pump 30 that circulates the slurry D1 between the crystallizer 4 and the circulation line Po. In the following description, the particles may be referred to as fine particles or fine particles of a metal compound. Furthermore, the crystallization system 10A may be referred to as a manufacturing system for fine particles of a metal compound, and the crystallization device 4 may be referred to as a manufacturing device for fine particles of a metal compound.

The circulation pipeline Po has a bent portion Pp, which is a serpentine-shaped pipeline. Furthermore, the circulation pipeline Po has a pipe 22 that connects the crystallizer 4 to the bent portion Pp, a pipe 23 that connects the circulation pump 30 to the bent portion Pp, and a pipe 24 that connects the circulation pump 30 to the crystallizer 4. Note that the bent portion Pp is not limited to a serpentine shape, and may have a spiral shape.

The circulation pump 30 is a circulation pump that has the function of circulating the slurry D1 between the crystallizer 4 and the bent portion Pp at an adjustable flow rate. However, it is not necessarily limited to a circulation pump as long as it has a similar function; for example, an impeller with a controllable rotation speed may be provided in the pipe 23 or the pipe 24.

The crystallization device 4 includes a cylindrical reaction tank 1 with a bottom having a central axis O1 facing vertically, and a cylindrical stirring blade Wc. The stirring blade Wc can rotate around a hollow rotating shaft 3 extending upward along the central axis O1 from the center of the stirring blade Wc in a plan view, and is housed inside the reaction tank 1 with the central axis O1 as the same central axis. The rotating shaft 3 rotates by a torque supplied through a belt B from a prime mover M provided outside the crystallization device 4. The prime mover M is not particularly limited as long as it is a device that generates rotational power, such as a motor or an engine. The belt B that transmits the rotational force to the rotating shaft 3 is not particularly limited as long as it can transmit the rotational force, such as a chain or a gear. The bottom surface of the reaction tank 1 may be flat as shown in the figure, or may be a cone shape that is convex downward. An outlet 6 is provided at the top of the reaction tank 1, which can discharge the slurry containing particles (crystals) generated in the reaction tank 1 to the next process. A pressure indication controller that maintains or adjusts the pressure of the slurry D1 discharged from the discharge port 6 to the pipe 22 is provided in the pipe 22. Details of the mixing blade Wc will be described later.

The lower part of the reaction tank 1 is provided with an inlet 5a through which the first reaction liquid L1 and the slurry D1 flowing through the circulation pipe Po are supplied. The first reaction liquid L1 is generated by supplying and mixing auxiliary materials S _A and S _B from tanks (not shown) that store the external auxiliary materials S _A and S _B. The flow rates of the auxiliary materials S _A and S _B of the first reaction liquid L1 are maintained or adjusted by flow indication controllers FIC ₂ and FIC _3. The first reaction liquid L1 is supplied to the reaction tank 1 in a predetermined amount from the inlet 5a. The supply amount of the first reaction liquid L1 from the inlet 5a can be adjusted to a predetermined amount by, for example, adjusting the rotation speed of the circulation pump 30. A pressure indicator PI ₁ is provided as necessary in the pipe 24 through which the first reaction liquid L1 flows.
A second reaction liquid L2 is supplied into the reaction tank 1 from a liquid supply section (second liquid supply section) 5b provided on the stirring blade Wc. The second reaction liquid L2 is supplied from an external tank (not shown) that stores the main raw material S _M. The flow rate of the second reaction liquid L2 is maintained or adjusted by a flow rate indicating controller _FIC1 .
The first reaction liquid L1 and the second reaction liquid L2 supplied to the reaction vessel 1 react with each other to generate precipitated and crystallized fine particles of a metal compound. The slurry D1 is a fluid containing the fine particles of the metal compound.

The bent portion Pp is composed of a plurality of straight pipe sections (Po1, Po2, Po3, Po4, Po5, Po6) with an inner diameter r2 arranged to face substantially the same direction with a space between them, a plurality of curved pipe sections C ( _C1 , C2, C3, C4, _C5 ) with an inner diameter r3 that connect the adjacent straight pipe sections Po1, _Po2 , _Po3 , _Po4 , Po5, Po6 in a separable or detachable manner, and a fixing plate 21 that fixes the plurality of straight pipe sections. The fact that the plurality of curved pipe sections C are separable means that, for example, the curved pipe section _C5 that is provided to connect the straight pipe section Po5 and the straight pipe section Po6 can be separated from the straight pipe section Po5 and the straight pipe section Po6.
As a method of attaching and detaching the curved pipe section _C5 to the straight pipe sections Po5 and Po6, flange sections (not shown) are provided on both ends of the curved pipe section _C5 and on the left ends of the straight pipe sections Po5 and Po6, and the curved pipe section _C5 may be attached and detached to and from the straight pipe sections Po5 and Po6 by fastening and loosening the flange sections using bolts, nuts, etc. The attachment and detachment method is not limited to this, and as long as it is freely attachable and detachable, for example, it is not limited to a method using flange sections, and the curved pipe section _C5 may be attached and detached by screwing both ends to the left ends of the straight pipe sections Po5 and Po6.
Although the fixed plate 21 has a rectangular shape in FIG. 1, the material and shape thereof are not particularly limited as long as the multiple straight pipe sections Po1, Po2, Po3, Po4, Po5, and Po6 can be held in a fixed state by the fixed plate 21.
As described above, in the case of multiple separable straight pipe sections and multiple curved pipe sections C, the inner surfaces of the straight pipe sections and curved pipe sections C can be easily cleaned by separating them, thereby improving the maintainability of the crystallization system 10A.

In the example of Figure 1, the straight pipe section is composed of six straight pipe sections, namely straight pipe section Po1, straight pipe section Po2, straight pipe section Po3, straight pipe section Po4, straight pipe section Po5, and straight pipe section Po6, and the curved pipe section C is composed of five curved pipe sections, namely curved pipe section _C1 , curved pipe section _C2 , curved pipe section _C3 , curved pipe section _C4 , and curved pipe section _C5 , but is not limited to this example.
The straight pipe section Po may be composed of six or more straight pipe sections Po, or six or less straight pipe sections Po. The number of curved pipe sections C increases or decreases according to the number of straight pipe sections Po. For example, in the example of FIG. 1, the second end of the curved pipe section _C2 , the first end of which is connected to the right end of the straight pipe section Po3, may be connected to the left end of the pipe 22. In this case, the curved pipe section _C2 may be provided with a bellows section that is capable of expanding and contracting, so that the curved pipe section _C2 may be capable of expanding and contracting.

In this way, the pipeline length of the bent section Pp, i.e., the total length of the straight pipe sections and curved pipe sections C (the number of straight pipe sections and curved pipe sections C), can be adjusted as desired to retain the slurry D1 for the desired retention time. That is, if a longer retention time is desired, it is desirable to increase the number of straight pipe sections and curved pipe sections C to lengthen the pipeline length of the bent section Pp, and if a shorter retention time is desired, it is desirable to decrease the number of straight pipe sections and curved pipe sections C to shorten the pipeline length of the bent section Pp.

The flow rate of the slurry D1 is determined by the specific gravity and diameter of the particles that make up the slurry D1. In other words, the settling speed of the particles that make up the slurry D1 is determined by the specific gravity and diameter of the particles that make up the slurry D1, so the flow rate of the slurry D1 is determined so that the slurry D1 flows without settling in the piping. Therefore, the pipe length of the bent section Pp can be calculated from the desired residence time of the slurry D1 and the flow rate of the slurry D1 to prevent the slurry D1 from settling.

The crystallizer 4 and the bent portion Pp are connected by a pipe 22 having an inner diameter r1. The bent portion Pp and the circulation pump 30 are connected by a pipe 23 having an inner diameter r4. The circulation pump 30 and the crystallizer 4 are connected by a pipe 24 having an inner diameter r5.
1, the inner diameter of the circulation pipeline Po, i.e., the inner diameter r1 of the pipe 22, the inner diameter r2 of the straight pipe sections Po1, Po2, Po3, Po4, Po5, and Po6, the inner diameter r3 of the curved pipe sections _C1 , _C2 , _C3 , _C4 , and _C5 , the inner diameter r4 of the pipe 23, and the inner diameter r5 of the pipe 24 are all the same. In this case, the cross-sectional areas of the pipe 22, the straight pipe sections Po1, Po2, Po3, Po4, Po5, and Po6, the curved pipe sections _C1 , _C2 , _C3 , _C4 , and _C5 , the pipe 23, and the pipe 24 are constant, which makes it easy to perform a flow analysis of the slurry D1 flowing through the pipelines. However, without being limited to the above example, the inner diameters of the circulation pipeline Po, i.e., the inner diameter r1 of the pipe 22, the inner diameter r2 of the straight pipe sections Po1, Po2, Po3, Po4, Po5, and Po6, the inner diameter r3 of the curved pipe sections _C1 , _C2 , _C3 , _C4 , and _C5 , the inner diameter r4 of the pipe 23, and the inner diameter r5 of the pipe 24 may be different from one another. In that case, the flow analysis may be performed taking into account the different inner diameters.

A pipeline connected to a slurry discharge pump 31 is connected to the pipe 23 through which the slurry D1 discharged from the bent portion Pp flows. This pipeline extracts the slurry D1 from the pipe 23 and accumulates it to become a product. A flow indication controller _FIC4 is provided near the slurry discharge pump 31 to maintain or adjust the flow rate of the slurry D1 extracted to the outside of the crystallization system 10A. The slurry discharge pump 31 is a slurry discharge pump having a function of adjusting the flow rate, similar to the circulation pump 30. However, the slurry discharge pump 31 is not necessarily limited to a slurry discharge pump as long as it has a function of extracting the slurry D1 from the pipe 23, and for example, an impeller capable of controlling the rotation speed may be provided in the pipeline.
The pressure of the slurry D1 in the pipe 23 immediately after the slurry D1 is drawn out to the outside is monitored by a pressure indicator _PI2 as required.

In the crystallization system 10A, at least a portion of the bent portion Pp is provided inside the temperature adjustment tank 13.
The temperature adjustment tank 13 is a member that maintains a state in which a refrigerant CW such as cold water flows in one direction inside the temperature adjustment tank 13 by a pump or the like (not shown). When at least a part of a bent portion Pp is provided in such a temperature adjustment tank 13, the refrigerant collides with the straight pipe portions Po1, Po2, Po3, Po4, Po5, and Po6 of the bent portion Pp. In this case, heat exchange is performed between the slurry D1 flowing through the straight pipe portions Po1, Po2, Po3, Po4, Po5, and Po6 of the bent portion Pp and the refrigerant CW via the members that constitute the straight pipe portions Po1, Po2, Po3, Po4, Po5, and Po6. Thus, the slurry D1 can be cooled or heated.
1, the straight pipe sections Po1, Po2, Po3, Po4, Po5, and Po6 are provided substantially perpendicular to the flow direction of the refrigerant CW, but the straight pipe sections Po1, Po2, Po3, Po4, Po5, and Po6 do not necessarily have to be provided substantially perpendicular to the flow direction of the refrigerant CW, and may be provided at an angle other than perpendicular. Also, heat exchange with the refrigerant CW may be performed in the curved pipe section C of the bent portion Pp, or heat exchange with the refrigerant CW may be performed in both the straight pipe section and the curved pipe section C of the bent portion Pp.

Here, the temperature adjustment capability for the slurry D1 can be adjusted by adjusting the length of the straight pipe sections Po1, Po2, Po3, Po4, Po5, and Po6 of the bent section Pp, or the number of the straight pipe sections Po1, Po2, Po3, Po4, Po5, and Po6. For example, if the heat quantity Q1 is transferred from the slurry D1 having the heat quantity Q flowing through the straight pipe section Po1 to the refrigerant CW by heat exchange, the heat quantity Q2 is transferred from the slurry D1 having the heat quantity (Q-Q1) flowing through the straight pipe section Po2 to the refrigerant CW by heat exchange. Furthermore, if the heat quantity Q3 is transferred from the slurry D1 having the heat quantity (Q-(Q1+Q2)) flowing through the straight pipe section Po3 to the refrigerant CW by heat exchange, the heat quantity of the slurry D1 flowing through the straight pipe section Po4 becomes (Q-(Q1+Q2+Q3)). By repeating this process a desired number of times, the amount of heat in the slurry D1 can be reduced, allowing the slurry D1 to be cooled by a desired amount. The same applies when heating the slurry D1.

According to the crystallization system 10A equipped with the circulation line Po having such a bent portion Pp, the slurry D1 containing particles produced in the crystallization device 4 can be easily mixed completely and uniformly by controlling the flow rate of the circulation pump 30. Furthermore, by adjusting the length of the pipeline at the bent portion Pp, the slurry D1 containing particles produced in the crystallization device 4 can be retained for a desired time without requiring a retention tank. Therefore, the retention time of the slurry D1 at the bent portion Pp can be adjusted without performing the complex flow analysis of the slurry D1 required when a retention tank is used. A retention tank (not shown) may be added to the crystallization system 10A.

In addition, with this type of crystallization system 10A, the slurry D1 can be cooled or heated by the desired amount by adjusting the pipe length of the bent section Pp where heat exchange with the refrigerant CW takes place, i.e., the pipe length or number of the straight pipe sections Po1, Po2, Po3, Po4, Po5, and Po6.

Next, the stirring impeller Wc of the crystallization system 10A will be described in detail. The stirring impeller Wc includes a cylindrical portion 2, a disk-shaped disk portion 8 whose outer periphery is fixed to the inner periphery 2i of the cylindrical portion 2, and a second disk portion 15 whose outer periphery is fixed to the inner periphery 2i of the upper end of the cylindrical portion 2.
The disk portion 8 is provided at a position where the height of the cylindrical portion 2 is approximately half, but is not limited to this example, and may be provided below or above approximately half the height of the cylindrical portion 2. The rotating shaft 3 is fixed to the center of the disk portion 8 in a plan view.
The second disk portion 15 is a disk-shaped member provided above the disk portion 8, and has a hole through which the rotating shaft 3 passes at the center in a plan view. Except for the hole through which the rotating shaft 3 passes, there is no hole that passes through the second disk portion 15 in the direction of the central axis O1. Therefore, the first reaction liquid L1, the second reaction liquid L2, and the mixture thereof do not enter inside the second disk portion 15.
The hollow interior of the rotating shaft 3 is a pipe line P1. A plurality of pipe lines P2 extend radially from the center toward the outer edge inside the disk portion 8. The pipe line P1 of the rotating shaft 3 and the pipe line P2 of the disk portion 8 are connected to each other. The second reaction liquid L2 is supplied to the rotating shaft 3 of the stirring blade Wc from a tank (not shown) that stores the main raw material S _M provided outside the crystallizer 4. The second reaction liquid L2 is supplied to the hollow pipe line P1 of the rotating shaft 3 via the rotary joint R, and is then supplied to the pipe line P2 of the disk portion 8. The tip of the pipe line P2 on the radial outer side of the reaction tank 1 opens downward and is used as a liquid supply section (second liquid supply section) 5b from which the second reaction liquid L2 is discharged. Therefore, a plurality of liquid supply sections 5b are provided in the disk portion 8 at intervals in the circumferential direction of the disk portion. For example, eight liquid supply sections 5b are provided. The number of liquid supply parts 5b is not limited, but it is preferable to provide them symmetrically with respect to the central axis O1.

In this embodiment, the distance between the inner circumferential surface 2i of the cylindrical portion 2 of the impeller Wc and the center of the liquid supply portion 5b is 2 mm or less. As shown in FIG. 2, if the distance (clearance) between the outer circumferential surface 2o of the cylindrical portion 2 of the impeller Wc and the inner circumferential surface 1i of the reaction tank 1 is L3, and the height along the central axis O1 of the impeller Wc (cylindrical portion 2) is He, it is preferable that the ratio He/L3 between He and L3 is 10 or more. It is more preferable that He/L3 is 25 or more. Therefore, even if a device of a different size from this embodiment is used, a similar device can be manufactured based on this ratio. The impeller Wc rotates at a peripheral speed of 5 m/s or more and 50 m/s or less. The ratio of He/L3 may differ from the above ratio depending on the purpose. For example, if it is desired to suppress crystal crushing, the ratio may be lowered from the above value.

In the cylindrical portion 2 of the impeller Wc, a plurality of holes h penetrating the cylindrical portion 2 in the radial direction are provided below the disk portion 8. These holes h allow the first reaction liquid L1, the second reaction liquid L2, or a mixture thereof to flow. Therefore, the first reaction liquid L1, the second reaction liquid L2, or a mixture thereof can move from the inside to the outside of the impeller Wc, or from the outside to the inside of the impeller Wc, through the plurality of holes h. In this way, when the plurality of holes h penetrating the cylindrical portion 2 in the radial direction are provided below the disk portion 8, the impeller Wc can be rotated with less power than when the plurality of holes h are provided on both the lower and upper sides of the disk portion 8.
Such a cylindrical portion 2 may be formed by processing the cylindrical portion 2 before processing, in which the holes h are evenly provided along the height direction of the cylindrical portion 2, so as to close the holes h above the disk portion 8, thereby forming the cylindrical portion 2 in which the holes h are provided only below the disk portion 8. Alternatively, the cylindrical portion 2 may be formed by processing the cylindrical portion 2 so as to provide the holes h only below the disk portion 8, and not processing the cylindrical portion 2 so as to provide the holes h above the disk portion 8.

In the crystallizer 4 equipped with such an agitator Wc, a predetermined amount of the first reaction liquid L1 is supplied to the reaction tank 1 from the inlet 5a. The amount of the first reaction liquid L1 supplied may be enough to fill the reaction tank 1 (full liquid state), or may be enough to press the first reaction liquid L1 against the inner circumferential surface 1i of the reaction tank 1 by the centrifugal force generated in the first reaction liquid L1 as the agitator W rotates and the first reaction liquid L1 performs a circular motion around the central axis O1 of the reaction tank 1, forming a liquid film of the first reaction liquid L1 on the inner circumferential surface 1i of the reaction tank 1. In the following, a description will be given assuming that the first reaction liquid L1 is supplied to the extent that the reaction tank 1 is full. In addition, the first reaction liquid L1 may be supplied to an extent that the above-mentioned liquid-filled state or liquid film formation state is achieved, and then the supply of the first reaction liquid L1 may be stopped and the reaction may be carried out in the reaction tank 1 (batch method described later), or the reaction in the reaction tank 1 may be carried out continuously while maintaining the first reaction liquid L1 at a flow rate sufficient to achieve the above-mentioned liquid-filled state or liquid film formation state (continuous method described later).
For example, by providing an aperture adjustment valve (not shown) at the discharge port 6 and adjusting the aperture of this aperture adjustment valve, the reaction tank 1 can be selected to be in either a liquid-filled state or a liquid film state in which a liquid film is formed.

When the reaction vessel 1 is filled with the first reaction liquid L1, the stirring blade Wc is rotated and the second reaction liquid L2 is discharged from the liquid supply section 5b along the inner circumferential surface 2i of the cylindrical portion 2 of the stirring blade Wc, thereby supplying the second reaction liquid L2 into the reaction vessel 1. In this way, the second reaction liquid L2 discharged from the liquid supply section 5b along the inner circumferential surface 2i of the cylindrical portion 2 of the stirring blade Wc comes into contact with the first reaction liquid L1 that is rotating in association with the rotation of the stirring blade Wc in the reaction vessel 1 filled with the first reaction liquid L1 near the inner circumferential surface 2i of the cylindrical portion 2 of the stirring blade Wc in the reaction vessel 1 filled with the first reaction liquid L1. In this way, the first reaction liquid L1 and the second reaction liquid L2 come into contact with each other, causing a reaction to occur and particles to be generated.

At this time, the second reaction liquid L2 is supplied to the first reaction liquid L1 from the liquid supply section 5b of the stirring blade Wc, which rotates at a peripheral speed of 5 m/s to 50 m/s, so that the second reaction liquid L2 can be mixed uniformly with the first reaction liquid L1.

Here, due to the centrifugal force generated in the first reaction liquid L1 rotating with the rotation of the agitator Wc, the second reaction liquid L2 discharged from the liquid supply part 5b of the agitator Wc rotating at a peripheral speed of 5 m/s to 50 m/s, and the mixed liquid, the first reaction liquid L1, the second reaction liquid L2, and the mixed liquid (hereinafter, sometimes collectively referred to as the mixed liquid) move radially outward from the cylindrical part 2 of the agitator Wc, collide with the inner surface 1i of the reaction tank 1 through multiple holes h provided in the cylindrical part 2 of the agitator Wc, and then move vertically along the inner surface 1i of the reaction tank 1. The mixed liquid that mainly moves downward is attracted by the flow toward the radial outward direction caused by the centrifugal force generated by the rotation of the agitator Wc, and again passes through multiple holes h provided in the cylindrical part 2 of the agitator Wc to collide with the inner surface 1i of the reaction tank 1, and then moves vertically along the inner surface 1i of the reaction tank 1, thereby generating convection. Here, when the mixed liquid passes through the multiple holes h, the mixed liquid is accelerated radially outward due to the effect of the throttle flow path, so the radially outward flow velocity of the mixed liquid is the highest in the vicinity of the multiple holes h. Furthermore, a shear force is applied in the circumferential direction to the mixed liquid that exists between the outer peripheral surface 2o and inner peripheral surface 2i of the cylindrical portion 2 of the stirring impeller Wc, which rotates at a peripheral speed of 5 m/s to 50 m/s, and the inner peripheral surface 1i of the fixed reaction vessel 1. The shear force applied to the mixed liquid is greater the closer it is to the inner peripheral surface 2i and outer peripheral surface 2o of the cylindrical portion 2 of the stirring impeller Wc. The shear force applied to the mixed liquid is a major factor that determines the particle size and uniformity of the particles obtained. In particular, the greater the applied shear force, the finer the particle size of the particles that can be obtained.

In the crystallization device 4 of this embodiment, the liquid supply section 5b is provided on the outer edge of the disk section 8. Specifically, as described above, the distance between the inner circumferential surface 2i of the cylindrical section 2 of the impeller Wc and the center of the liquid supply section 5b is set to 2 mm or less. Therefore, at the reaction initiation point where the second reaction liquid L2 discharged from the liquid supply section 5b along the inner circumferential surface 2i of the cylindrical section 2 of the impeller Wc and the first reaction liquid L1 rotating with the rotation of the impeller Wc near the inner circumferential surface 2i of the cylindrical section 2 of the impeller Wc come into contact for the first time and start the reaction, a maximum shear force is applied in addition to the flow toward the radial outside due to the centrifugal force and the effect of the throttle flow path. Therefore, the region where the applied shear force is the largest can be set as the reaction initiation point. Specifically, the reaction initiation point can be formed in a region close to the inner circumferential surface 2i and the outer circumferential surface 2o of the cylindrical section 2 of the impeller Wc, for example, within 2 mm. Here, the mixed liquid can move from the inner circumferential side to the outer circumferential side of the cylindrical section 2 through the above-mentioned multiple holes h. Therefore, the stirring of the first reaction liquid L1 and the second reaction liquid L2 at the reaction initiation point is promoted by the shear force. Therefore, more uniform mixing of the first reaction liquid L1 and the second reaction liquid L2 is started from the reaction initiation point, and the mixing and reaction are carried out in the reaction field where the reaction occurs along the flow of the mixed liquid, thereby producing fine particles having a uniform diameter. Here, the reaction initiation point refers to the area where the reaction is started, and the reaction field refers to the entire field where the reaction occurs. Therefore, the reaction initiation point is included in the reaction field.
A baffle (baffle plate) 7 shown in Fig. 2 may be provided on the inner peripheral surface of the reaction vessel 1 corresponding to the upper part of the mixing blade Wc. When the reaction vessel 1 is filled with liquid, the baffle 7 has the effect of suppressing the generation of vortexes and promoting the mixing of the mixed liquid. On the other hand, when the reaction vessel 1 is not filled with liquid and a liquid film of the mixed liquid is formed, it is not necessary to provide the baffle 7.
The baffle 7 is not an essential component and may not be provided. For example, if a mechanical seal (not shown) is provided at the location in the reaction tank 1 where the rotating shaft 3 is inserted, and a completely liquid-filled state without a gas phase is achieved, the generation of vortexes is suppressed, and therefore the baffle 7 may not be provided. If the baffle 7 is not provided, the flow path resistance is reduced, and the power of the prime mover M can be reduced.

The same effect can be obtained even when the container is not filled with liquid but instead a liquid film is formed.

According to the crystallization system 10A including such a crystallizer 4, it is possible to individually adjust the shear force, the circulation amount of the first reaction liquid L1, and the residence time of the slurry, which affect the particle quality such as the particle size, particle size distribution, and sphericity of the reaction product in the crystallizer 4, and thus further improve the control performance of the particle quality.

The crystallizer 4 of such a crystallization system 10A is further provided with a control unit CON capable of controlling the rotation speed of the prime mover M. Therefore, by controlling the rotation speed of the prime mover M with the control unit CON, the rotation speed (circumferential speed) of the agitator blade Wc can be controlled.
The control unit CON is a computer that controls the rotation speed of the prime mover M based on the operation by the operator of the crystallization system 10A. That is, the control unit CON may be a known computer including a CPU, RAM, ROM, etc. that can perform the above-mentioned control. The details of the control by the control unit CON may be defined by software that can be arbitrarily changed or updated by the user. As shown in FIG. 1 and FIG. 2, the control unit CON is electrically or electronically connected to the prime mover M. In addition, the control unit CON may include a rotation speed sensor that measures the rotation speed of the stirring blade Wc (rotating shaft 3), and the control unit CON may control the rotation speed of the prime mover M so that the rotation speed signal received from the rotation speed sensor corresponds to the desired peripheral speed. For example, when the prime mover M is a motor, the control unit CON may control the rotation speed of the motor by controlling the drive voltage of the motor. When the prime mover M is an engine, the control unit CON may control the rotation speed of the engine by controlling the amount of fuel supplied to the engine.

Using this crystallization system 10A, the residence time of the crystals in the reaction tank 1 and the pH in the reaction tank 1 were fixed at constant conditions, and the average particle diameter d50 of the microparticles obtained was measured when the peripheral speed of the agitator blade Wc was changed. As a result, the average particle diameter d50 of the microparticles obtained when the peripheral speed of the agitator blade Wc was 20 m/s was 3.79 μm (measurement point a). The average particle diameter d50 of the microparticles obtained when the peripheral speed of the agitator blade Wc was 40 m/s was 1.71 μm (measurement point b). The average particle diameter d50 of the microparticles obtained when the peripheral speed of the agitator blade Wc was 50 m/s was 1.32 μm (measurement point c).

Figure 3 shows a graph obtained by interpolating the obtained measurement points a, b, and c using a known method. It was confirmed from Figure 3 that as the peripheral speed of the stirring blade Wc increases, fine particles with a smaller average particle diameter d50 are obtained. It was also confirmed from Figure 3 that when the peripheral speed is approximately 25 m/s or more, the obtained average particle diameter d50 is 3 μm or less. Here, a peripheral speed of approximately 25 m/s or more refers to a peripheral speed between 23 m/s and 25 m/s or more, where the average particle diameter d50 is 3 μm or less.

From the results of FIG. 3, it was confirmed that by using the crystallization system 10A and setting the peripheral speed of the agitator blade Wc to approximately 25 m/s or more, fine particles with an average particle diameter d50 of 3 μm or less can be obtained. It was also confirmed that by increasing the peripheral speed of the agitator blade Wc, fine particles with a smaller average particle diameter d50 can be obtained. This is thought to be due to the fact that, since shear force is generated in a fluid due to the speed difference, the more the peripheral speed of the agitator blade Wc is increased, the greater the speed difference between the mixed liquid rotating with the agitator blade Wc and the mixed liquid stationary in the reaction tank 1 becomes, and a greater shear force is applied to the mixed liquid. Therefore, the control unit CON, which controls the peripheral speed of the agitator blade Wc by controlling the rotation speed of the prime mover M, controls the shear force applied to the mixed liquid and further controls the average particle diameter d50 of the fine particles produced.

The microparticles obtained in Fig. 3 are metal compounds containing nickel, cobalt, and manganese. More specifically, they are ternary metal hydroxides composed of nickel, cobalt, and manganese. In these microparticles, the substance amount ratio of nickel is 90% or more. The substance amount ratio of 90% or more here means that the substance amount of nickel is 90% or more when the total substance amount of nickel, cobalt, and manganese is 100. Therefore, it was confirmed that, despite the high nickel content, minute microparticles with an average particle size d50 of 3 µm or less were obtained.
The fine particles are not necessarily limited to fine particles of a ternary metal hydroxide composed of nickel, cobalt, and manganese, but may be fine particles of a metal compound composed of nickel, cobalt, and aluminum.

Here, the results in Fig. 3 were obtained when the crystallization system 10A was operated in a continuous mode. The continuous mode refers to an operating form in which the main raw material S _M and the auxiliary raw materials S _A and S _B are continuously supplied during the operation of the crystallization system 10A shown in Fig. 1, and the slurry D1 containing the generated fine particles is continuously discharged from the crystallization system 10A to the outside. Since the substance ratio of nickel in the ternary metal hydroxide composed of nickel, cobalt, and manganese produced by the crystallization system 10A is 90% or more, the substance ratio of nickel in the metal-based raw materials input to the crystallization system 10A is also 90% or more.
In addition to the continuous operation, there is also a batch operation, in which the main raw material S _M and the auxiliary raw materials S _A and S _B are not supplied during the operation of the crystallization system 10A, but a predetermined amount of the main raw material S _M and the auxiliary raw materials S _A and S _B are supplied to the crystallization system 10A before starting the operation of the crystallization system 10A, the crystallization system 10A is operated, and the slurry D1 containing the generated fine particles is discharged to the outside after the operation of the crystallization system 10A is stopped.

Figure 4 is an electron microscope photograph of fine particles obtained by operating the crystallization system 10A in such a continuous manner so that the peripheral speed of the agitator blade Wc is approximately 25 m/s or more. It can be seen that the sphericity of the particles is high, 0.85 or more on average. In this case, the average particle diameter d50 was 1.32 μm. Figure 5 is an electron microscope photograph of fine particles obtained by a conventional technique that does not use an agitator blade shaped like the agitator blade Wc of the crystallization system 10A. It can be seen that the sphericity of the fine particles is clearly lower than that of the fine particles in Figure 4. In this case, the average particle diameter d50 was 1.37 μm.

Figure 6 is an electron microscope photograph of microparticles obtained by operating crystallization system 10C or crystallization system 10D (described below) in a batch mode. As with the microparticles obtained in the continuous mode shown in Figure 4, it can be seen that even when operated in a batch mode, the sphericity of the particles is 0.9 or more on average, and microparticles with high sphericity can be obtained. Furthermore, compared to the continuous mode, the uniformity of the particle size distribution is greatly improved, achieving a span: (d90-d10)/d50 = 0.7 or less. In this case, the average particle diameter d50 was 1.40 μm.

Therefore, according to the crystallization system 10A including the crystallizer 4 equipped with the control unit CON capable of controlling the circumferential speed of the stirring blade Wc, it is possible to obtain fine particles of a ternary metal hydroxide composed of nickel, cobalt, and manganese, which has a high sphericity, a high nickel content of 90% or more in terms of substance amount ratio, and a small average particle diameter d50 of 3 μm or less. Furthermore, the average particle diameter d50 of the obtained fine particles of the metal compound can be controlled by mainly adjusting the circumferential speed of the stirring blade Wc under the control of the control unit CON. That is, by providing the control unit CON capable of controlling the circumferential speed of the stirring blade and making it possible to individually adjust the shear force and the circulating flow, stirring specialized for the transmission of shear force is possible in the reaction tank 1. That is, the shear force applied to the mixed liquid in the reaction tank 1 is adjusted by adjusting the circumferential speed of the stirring blade Wc, and the circulating flow is adjusted by adjusting the rotation speed of the circulating pump 30 in FIG. 1. The great advantage of this mechanism improvement is that the particle diameter can be controlled mainly by adjusting the circumferential speed of the stirring blade Wc. Conventionally, particle size control relied on adjusting the residence time and pH value, but with the residence time and pH value set to constant under conditions that do not degrade product quality, particle size can be controlled primarily by adjusting the peripheral speed of the stirring blades Wc, dramatically improving particle size control performance. This improved functionality makes it possible to control particle size while maintaining the residence time and pH value that do not cause deterioration of particle shape, and to obtain a high-quality metal hydroxide with a high nickel content and a small average particle size d50 and high sphericity.

<First Modification of First Embodiment>
7 is a schematic diagram showing a crystallization system 10B according to a first modified example of the first embodiment of the present invention. In the following description, only the differences from the crystallization system 10A according to the first embodiment will be described.

Crystallization system 10B differs from crystallization system 10A in that the shape of the agitator blade Wd is different from that of the agitator blade Wc of crystallization system 10A, and in that the bent portion Pp is not provided inside the temperature adjustment tank 13.

As shown in FIG. 7, the stirring blade Wd is different from the stirring blade Wc in that the disk portion 8 is provided at the upper end of the cylindrical portion 2. In addition, the height of the cylindrical portion 2 is about half the height of the cylindrical portion 2 of the stirring blade Wc. By using a crystallization device 4d equipped with such a stirring blade Wd, the same effect as the crystallization device 4 equipped with the stirring blade Wc can be achieved. In addition, since the cylindrical portion 2 is not provided above the disk portion 8, the stirring blade Wd can be made lighter than the stirring blade Wc. In addition, since the stirring blade Wd can be made to have a simple structure, the stirring blade Wd can be operated with less power than the stirring blade Wc, and energy saving of the crystallization device 4d and ease of manufacturing the stirring blade Wd can be expected. Furthermore, since the height of the cylindrical portion 2 is kept short, the crystallization device 4d can be made smaller.

The use of the crystallization system 10B according to the first modified example including such a crystallizer 4d can produce fine particles of a ternary metal hydroxide composed of nickel, cobalt, and manganese, which has high sphericity, a high nickel content of 90% or more in terms of substance amount ratio, and a very small average particle diameter d50 of 3 μm or less. This can be achieved in the same manner as the use of the crystallization system 10A.
The crystallization system 10B may be provided with the temperature adjustment tank 13 used in the crystallization system 10A. In this case, the slurry D1 can be cooled or heated by a desired amount in the same manner as in the crystallization system 10A.

<Second Modification of First Embodiment>
8 is a schematic diagram showing a crystallization system 10C according to a second modified example of the first embodiment of the present invention. In the following description, only the differences from the crystallization system 10A according to the first embodiment will be described.

Crystallization system 10C differs from crystallization system 10A in that a retention tank 10 is provided instead of the bent portion Pp of crystallization system 10A.

The crystallization system 10A and the crystallization system 10B are configured to be used when operating in a continuous manner, whereas the crystallization system 10C is configured to be used when operating in a batch manner. In this case, a larger device capacity can be secured than when using the bent portion Pp, so that in a batch manner in which the system forming the crystallization system 10C during operation is closed to the outside, more fine particles can be produced in one operation. Therefore, fine particles can be produced efficiently. Even when such a crystallization system 10C is operated in a batch manner, fine particles having a high sphericity, a high nickel content of 90% or more in terms of substance amount ratio, and an average particle diameter d50 of 3 μm or less can be produced, as shown in FIG. 6. Furthermore, when fine particles are produced in a batch manner, the uniformity of the particle size distribution is significantly improved compared to the continuous manner, and a span: (d90-d10)/d50=0.7 or less can be achieved.
The retention tank 10 of the crystallization system 10C may be provided with an agitator (not shown). For example, a known screw-type agitator may be provided as the agitator. In this case, the fluidity in the retention tank 10 can be further improved, and the dispersibility when raw materials and additives are added to the retention tank 10 can be improved.

<Third Modification of First Embodiment>
9 is a schematic diagram showing a crystallization system 10D according to a third modified example of the first embodiment of the present invention. In the following description, only the differences from the crystallization system 10C according to the second modified example of the first embodiment will be described.

Crystallization system 10D differs from crystallization system 10C in that a concentrator 11 is connected to the retention tank 10 of crystallization system 10C.

By combining the crystallization system 10D with a concentrator 11, it is possible to increase the slurry concentration in the device and improve the production volume per unit volume. In principle, the slurry has fluidity and the slurry concentration can be increased to a concentration that allows it to be pumped. A filter, a centrifuge, a thickener, or the like can be applied to the concentrator 11. When such a crystallization system 10D is used, it is possible to produce fine particles having a high sphericity, a high nickel content of 90% or more in terms of substance amount ratio, and an average particle diameter d50 of 3 μm or less, as shown in FIG. 6.
The retention tank 10 of the crystallization system 10D may be provided with an agitator (not shown). For example, a known screw-type agitator may be provided as the agitator. In this case, the fluidity in the retention tank 10 can be further improved, and the dispersibility when raw materials and additives are added to the retention tank 10 can be improved.

Here, the advantages of using the stirring blades Wc or Wd will be explained from a different perspective. Compared to using a flat disk turbine as disclosed in Patent Document 3, when operated with the same power, the stirring blades Wc or Wd, which have a blade diameter 1.25 times that of the flat disk turbine, can be operated at a peripheral speed 3.3 times that of the flat disk turbine. Therefore, when using the stirring blades Wc or Wd, a greater shear force can be applied to the micro-reaction field of the metal hydroxide than in the conventional technology. This is thought to be because, compared to the flat disk turbine, the stirring blades Wc or Wd receive less resistance from the water when rotated. Therefore, it is thought that the stirring blades Wc or Wd can be rotated at a higher speed, and therefore a greater shear force can be applied to the micro-reaction field of the metal hydroxide.

Second Embodiment
Fig. 10 is a schematic diagram of a crystallizer 40 of a crystallization system 20A according to a second embodiment of the present invention. The crystallization system 20A according to the second embodiment of the present invention is shown in Fig. 13. In the following description, the differences from the crystallization system 10B according to the first modified example of the first embodiment shown in Fig. 7 will be mainly described.

The crystallizer 40 of the crystallization system 20A differs in that the discharge port 6a opens in the direction in which the rotating shaft 3 extends in the reaction tank 1A, and that the agitator blade Ws of the crystallizer 40 has a different shape from the agitator blade Wd of the crystallization system 10B of the first modified example of the first embodiment.

In the reaction tank 1A in the crystallization device 40 of the crystallization system 20A of the second embodiment of the present invention, the inlet (first liquid supply section) 5a1 through which the first reaction liquid L1 is supplied is provided in the upper part of the reaction tank 1A, above the stirring blade Ws. In addition, in the reaction tank 1A in the crystallization device 40 of the crystallization system 20A of the second embodiment of the present invention, the discharge port 6a opens in the direction in which the rotation shaft 3 extends. In the example of FIG. 10, the discharge port 6a is provided at the bottom of the reaction tank 1A. Note that the bottom of the reaction tank 1A is not limited to a downwardly convex shape as shown in FIG. 10, and may be flat.

Figure 12 (a) shows a cross-sectional view taken along line AA in Figure 10. As shown in Figure 12 (a), the inlet 5a1 is connected to the reaction tank 1A so that the reaction liquid L1 that flows into the reaction tank 1A from the inlet 5a1 forms a vortex. The inlet 5a1 may be connected in the tangential direction of the reaction tank 1A so that the vortex is easily formed.

The impeller Ws shown in FIG. 10 differs from the impeller Wd of the crystallizer 4d shown in FIG. 7 in that the pipe P2 opens from the outer edge of the disk portion 8 toward the radially outward direction, and the liquid supply section (upper second liquid supply section) 5b1 that penetrates the cylindrical portion 2 in the radial direction and supplies the second reaction liquid L2 toward the radially outward direction of the cylindrical portion 2 into the reaction tank 1A is provided on the outer circumferential surface 2o of the cylindrical portion 2. Also, the impeller Wd of the crystallizer 4d shown in FIG. 7 differs in that the rotating shaft 3 further extends downward from the disk portion 8, and the liquid supply section (lower second liquid supply section) 5b2 that supplies the second reaction liquid L2 toward the radially outward direction of the cylindrical portion 2 into the reaction tank 1A from the lower end of the rotating shaft 3 toward the radially outward direction opens at the tip of the extension section 9 that extends from the lower end of the rotating shaft 3 toward the radially outward direction. Furthermore, it differs in that a plurality of through holes h1 are provided that penetrate the disk portion 8 in the direction in which the rotating shaft 3 extends. Here, the clearance between the inner circumferential surface 2i of the cylindrical portion 2 and the rotating shaft 3 is set to be larger than the clearance between the inner circumferential surface 1i of the reaction vessel 1A and the stirring blade Ws. In addition, the tip of the extension portion 9 is provided radially inward from the inner circumferential surface 2i of the cylindrical portion 2.

The structure of the stirring blade Ws will be described in more detail below. (b) of FIG. 12 shows a cross-sectional view taken along the line BB of FIG. 10. The pipe P2 branches from the pipe P1 provided inside the rotating shaft 3 toward the radially outer side of the rotating shaft 3. In the example of (b) of FIG. 12, four pipes P2 are provided and are equally spaced in the circumferential direction. The number of pipes P2 is not necessarily limited to four, but may be less than four or more than four as long as they are equally spaced in the circumferential direction around the rotating shaft 3. In the example of (b) of FIG. 12, the through holes h1 are slit-shaped extending in the circumferential direction of the cylindrical portion 2, and four of them are provided at equal intervals in the circumferential direction. The number of through holes h1 is not limited to four as long as they are equally spaced in the circumferential direction.

Figure 12(c) shows a cross-sectional view taken along line CC in Figure 10. Pipe P3 branches out from pipe P1 provided inside the rotating shaft 3 toward the radial outside of the rotating shaft 3. In the example of Figure 12(c), four pipes P3 are provided at equal intervals in the circumferential direction. The number of pipes P3 is not necessarily limited to four, but may be less than four or more than four as long as they are provided at equal intervals in the circumferential direction centered on the rotating shaft 3. The number of pipes P2 and the number of pipes P3 (number of extensions) may be the same or different.

Also, as shown in FIG. 10, an enlarged diameter portion 3a may be provided at the bottom of the rotating shaft 3, and the extensions 9 may extend radially outward from the enlarged diameter portion 3a. Alternatively, the enlarged diameter portion 3a may be provided detachably on the rotating shaft 3, and may be configured so that the enlarged diameter portion 3a is fastened to the rotating shaft 3 by a nut N from the bottom end of the enlarged diameter portion 3a. With this structure, the enlarged diameter portion 3a can be easily replaced with another enlarged diameter portion 3a having a different number of extensions 9.

In the crystallization apparatus 40 equipped with such a reaction tank 1A and an agitator Ws, the first reaction liquid L1 supplied from the inlet (first liquid supply section) 5a1 flows through the reaction tank 1A toward the outlet 6a. At that time, the first reaction liquid L1 rotates with the rotation of the agitator Ws. At this time, the second reaction liquid L2 is supplied radially outward from the upper second liquid supply section 5b1 and the lower second liquid supply section 5b2 provided on the rotating agitator Ws, that is, from two different locations in the direction in which the rotating shaft 3 extends (up and down direction). Therefore, the first reaction liquid L1 and the second reaction liquid L2 are mixed better than in the crystallization apparatus 4d and the crystallization apparatus 4. Furthermore, since a plurality of through holes h1 are provided through the disk portion 8 in the direction in which the rotating shaft 3 extends, the flow of the mixed liquid from the inlet 5a1 toward the outlet 6a is smoother than in the crystallizer 4d or the crystallizer 4, and pressure loss can be reduced. In other words, the flow resistance of the reaction tank 1A can be reduced with respect to the flow of the mixed liquid from the inlet 5a1 toward the outlet 6a, so that the pressure loss in the reaction tank 1A can be reduced. Therefore, the power consumption of the pump can be suppressed when increasing the circulation flow rate. In addition, the upper second liquid supply portion 5b1 and the lower second liquid supply portion 5b2 are open toward the radial outside, but the inner peripheral surface 1i of the reaction tank 1A is present on the radial outside of the upper second liquid supply portion 5b1 and the lower second liquid supply portion 5b2, and the outlet 6a is further open in the direction in which the rotating shaft 3 extends. Therefore, even if the circumferential speed of the impeller Ws increases and the centrifugal force acting on the mixed liquid rotating around the impeller Ws with the increased circumferential speed increases, the increase in the flow of the mixed liquid toward the radially outward direction due to the increase in centrifugal force is countered by the inner circumferential surface 1i of the reaction tank 1A. Therefore, unlike the case of the impeller Wd or the impeller Wc in the crystallizer 4d or the crystallizer 4 in which the outlet 6 opens toward the radially outward direction of the reaction tank 1, the increase in the circumferential speed of the impeller Ws does not directly lead to an increase in the circulation flow rate of the mixed liquid from the inlet 5a1 toward the outlet 6a. In other words, the increase in the circumferential speed of the impeller Ws increases only the shear force acting on the mixed liquid, and the increase in the circulation flow rate of the mixed liquid from the inlet 5a1 toward the outlet 6a can be made to depend only on the flow rate of the pump 30. Therefore, the circulation flow rate of the mixed liquid in the crystallization system 20A and the increase or decrease in the shear force acting on the mixed liquid due to the increase or decrease in the peripheral speed of the stirring blade Ws can be individually controlled with higher precision. Therefore, the characteristics of the generated particles can be controlled with higher precision.

13 is a schematic diagram of a crystallization system 20A according to a second embodiment of the present invention. The slurry D1 discharged from the outlet 6a of the crystallizer 40 flows into the retention tank 10 through the pipe 22. After being retained in the retention tank 10, the slurry D1 is discharged from an outlet provided at the bottom of the retention tank 10, flows into the pump 30 through the pipe 23, and is supplied to the reaction tank 1A from the inlet 5a1 through the pipe 24. The slurry D1 can be taken out to the outside from a pipe (not shown) provided in the pipe 23 using a slurry discharge pump or the like. Here, the inside of the retention tank 10 is at atmospheric pressure.
<Modification of the second embodiment>

Figure 11 is a schematic diagram of a crystallizer 41 according to a modified example of the crystallization system 20A of the second embodiment of the present invention. In the following explanation, only the differences from the crystallization system 40 of the second embodiment of the crystallization system 20A shown in Figure 10 will be explained.

The crystallizer 41 according to the modified example of the crystallization system 20A of the second embodiment shown in FIG. 11 is different from the crystallizer 40 in that an inlet (first liquid supply section) 5a2 for supplying the first reaction liquid L1 to the reaction tank 1B is provided at the bottom of the reaction tank 1B, and an outlet 6b is provided at the top of the reaction tank 1B. The stirring blade Ws used in the crystallizer 41 is the same as the stirring blade Ws used in the crystallizer 40. Even in this case, the outlet 6b opens in the direction in which the rotating shaft 3 extends in the reaction tank 1B, as in the crystallizer 40. Therefore, the same effect as the crystallizer 40 can be achieved.
<First Modification of the Crystallization System of the Second Embodiment>

FIG. 14 is a schematic diagram of a crystallization system 20B of a first modified example of the second embodiment of the present invention. The crystallization system 20B is different from the crystallization system 20A in that the retention tank 10 is not provided. When the reaction time or retention time can be short, the retention tank 10 may not be provided. By not providing the retention tank 10, the crystallization system 20B can be made compact. In addition, by not providing the retention tank 10, the crystallization system 20B can be made into a completely sealed structure. Therefore, the crystallization system 20B can be operated under pressure. In this case, the low pressure region generated around the stirring blade Ws due to the rotation of the stirring blade Ws is prevented from becoming equal to or lower than the saturated vapor pressure, so that the occurrence of cavitation can be suppressed and the quality of the particles can be stabilized.
<Second Modification of the Crystallization System of the Second Embodiment>

FIG. 15 is a schematic diagram of a crystallization system 20C according to a second modified example of the second embodiment of the present invention.
The crystallization system 20C is different from the crystallization system 20A in the configuration of the crystallizer 42. That is, the crystallization system 20C is different from the crystallization system 20A in that the second reaction liquid L2 is supplied into the reaction tank 1C not only from the upper second liquid supply part 5b1 and the lower second liquid supply part 5b2 provided on the stirring blade Ws, but also from the fixed side second liquid supply part 5b3 provided in the reaction tank 1C. Furthermore, an inlet (first liquid supply part) 5a1 for supplying the first reaction liquid L1 to the reaction tank 1C is provided so as to supply the first reaction liquid L1 in the tangential direction of the reaction tank 1C.

The fixed side second supply parts 5b3 are provided near the inner circumferential surface 1i of the reaction tank 1C, and supply the second reaction liquid L2 toward the bottom of the reaction tank 1C in the direction in which the rotation shaft 3 extends. Here, the fixed side second supply parts 5b3 are provided at equal intervals around the circumference of the reaction tank 1C. There is no limit to the number of fixed side second supply parts 5b3, as long as they are provided at equal intervals around the circumference of the reaction tank 1C.

In the crystallizer 42 of such a crystallization system 20C, an upper reaction area is formed in region A shown by a dashed line in FIG. 15, and a lower reaction area B is formed in region B shown by a dashed line. In the upper reaction area A, a reaction occurs when a second reaction liquid L2 is supplied from the fixed side second liquid supply section 5b3 to a first reaction liquid L1, which is supplied in the tangential direction of the reaction tank 1C and forms a vortex. Meanwhile, in the lower reaction area B, a reaction occurs between the first reaction liquid L1 supplied from the inlet (first liquid supply section) 5a1 and the second reaction liquid L2 supplied from the stirring blade Ws, as in the crystallizer 40.

Here, the shear force acting on the mixed liquid in the upper reaction area A is generated in the circumferential direction between the mixed liquid stationary on the inner circumferential surface 1i of the reaction tank 1C in the upper reaction area A and the mixed liquid that is radially inward of the inner circumferential surface 1i of the reaction tank 1C and rotates around the rotation axis 3 together with the first reaction liquid L1 supplied from the inlet 5a1. Since a shear force is generated in the fluid due to a speed difference, the shear force acting on the mixed liquid in the upper reaction area A depends on the circumferential speed of the mixed liquid in the upper reaction area A. In other words, it can be said that it depends on the circulation flow rate of the mixed liquid or the discharge amount of the pump 30. On the other hand, in the lower reaction area B, a shear force is generated in the circumferential direction of the mixed liquid that exists between the outer circumferential surface 2o and inner circumferential surface 2i of the cylindrical part 2 of the rotating stirring blade Ws and the inner circumferential surface 1i of the fixed reaction tank 1C. In other words, the shear force acting on the mixed liquid in the lower reaction area B depends on the circumferential speed of the stirring blade Ws. Therefore, the shear force acting on the mixed liquid in the upper reaction area A and the lower reaction area B can be individually controlled. Therefore, the crystallizer 42 can improve the adjustment function of not only the crystal particle size but also the crystal shape.

Furthermore, in the crystallizer 42, the number of places to supply the second reaction liquid L2 is increased, improving the dispersibility of the mixed liquid, and thus improving the production capacity of fine particles. Also, the second reaction liquid L2 can be divided into a system that supplies the upper second liquid supply part 5b1 and the lower second liquid supply part 5b2, and a system that supplies the fixed side second liquid supply part 5b3. Therefore, by supplying the main raw material S _M to one system and supplying a different additive X that contributes to improving the quality of the crystal product to the other system, it is possible to shorten the additive addition process and produce a product that contains the additive as an ingredient.

The above describes in detail an embodiment of the present invention and its variations with reference to the drawings, but the specific configuration is not limited to this embodiment and its variations, and also includes designs that do not deviate from the gist of the present invention and combinations of the embodiment and its variations.

1, 1A, 1B, 1C Reaction tank 2 Cylindrical part 3 Rotating shaft 4, 4d, 40, 41, 42 Crystallizer 5a Inlet (first liquid supply part)
5b Liquid supply section (second liquid supply section)
6 Discharge port 8 Disk portion h Hole 10A, 10B, 10C, 10D, 20A, 20B, 20C Crystallization system 22, 23, 24 Piping 30 Circulation pump 31 Second circulation pump Po Circulation line Pp Bent portion Po1, Po2, Po3, Po4, Po5, Po6 Straight pipe portion C, _C1 , _C2 , _C3 , _C4 , _C5 Bent pipe portion Wc, Wd, Ws Stirring blade

Claims (13)

A stirring blade having a plurality of holes penetrating in a radial direction and rotatable around a central axis;
a bottomed cylindrical reaction vessel capable of concentrically accommodating the stirring blade therein;
A first liquid supply unit provided in the reaction tank and capable of supplying a first reaction liquid to the inside of the reaction tank;
A second liquid supply part provided on the stirring blade and capable of supplying a second reaction liquid to the inside of the reaction tank;
A control unit for controlling the peripheral speed of the stirring blade;
An apparatus for producing fine particles of a metal compound, comprising: The stirring blade is
A cylindrical portion having the plurality of holes penetrating in the radial direction;
a disk-shaped portion having an outer peripheral portion fixed to an inner peripheral surface of the cylindrical portion;
a rotation axis extending upward from the center of the disk portion in a plan view along the central axis,
The apparatus for producing metal compound microparticles as described in claim 1, characterized in that the second reaction liquid can flow through the interior of the disk portion and the rotating shaft, and the second liquid supply portion is provided on the outer edge of the disk portion. The apparatus for producing fine particles of metal compounds according to claim 2, characterized in that the second liquid supply section opens downward. The apparatus for producing fine particles of metal compounds according to claim 3, characterized in that the plurality of holes penetrating in the radial direction are blocked in the cylindrical portion above the disk portion, and a second disk-shaped portion having an outer edge fixed to the inner peripheral surface of the cylindrical portion is provided at the upper end of the cylindrical portion. The apparatus for producing fine particles of metal compounds according to claim 3, characterized in that the disk portion is provided at the upper end of the cylindrical portion. The apparatus for producing fine particles of a metal compound according to any one of claims 2 to 5, characterized in that, when the clearance between the outer peripheral surface of the cylindrical portion and the inner peripheral surface of the reaction tank is L3 and the height of the cylindrical portion is He, He/L3 is 10 or more. The manufacturing device for metal compound microparticles according to any one of claims 1 to 5, characterized in that a plurality of the second liquid supply sections are provided. The manufacturing apparatus according to any one of claims 1 to 5;
a circulation pipe for flowing the slurry containing the fine particles discharged from an outlet of the manufacturing apparatus and circulating the slurry from the first liquid supply unit of the manufacturing apparatus into the manufacturing apparatus;
a circulation pump that circulates the slurry between the manufacturing apparatus and the circulation line;
2. A system for producing fine particles of a metal compound, wherein the circulation pipeline has a meandering bent portion. The stirring blade is
A cylindrical portion having the plurality of holes penetrating in the radial direction;
a disk-shaped portion having an outer peripheral portion fixed to an inner peripheral surface of the cylindrical portion;
a rotation axis extending upward from the center of the disk portion in a plan view along the central axis,
a through hole penetrating the disk portion in a direction in which the rotation shaft extends, the through hole being provided on a radially outer side of the disk portion;
The second liquid supply portion is provided at two different positions in a direction in which the rotation shaft extends,
the upper second liquid supply portion provided on the upper side is provided on the outer edge portion of the disk portion,
The lower second liquid supply portion is provided on an extension portion extending radially outward from a lower portion of the rotating shaft,
2. The apparatus for producing fine particles of a metal compound according to claim 1, wherein the second reaction liquid is capable of flowing through the interior of the rotating shaft, the disk portion, and the extension portion. The apparatus for producing fine particles of metal compounds according to claim 9, characterized in that the outlet of the reaction vessel is open in the direction in which the rotation shaft extends in the reaction vessel. The manufacturing apparatus according to claim 10;
a circulation pipe for flowing the slurry containing the fine particles discharged from the discharge port of the manufacturing apparatus and circulating the slurry from the first liquid supply unit of the manufacturing apparatus into the manufacturing apparatus;
a circulation pump that circulates the slurry between the manufacturing apparatus and the circulation line;
The system for producing fine particles of a metal compound is characterized in that the circulation pipeline includes a retention tank. The manufacturing apparatus according to claim 10;
a circulation pipe for flowing the slurry containing the fine particles discharged from the discharge port of the manufacturing apparatus and circulating the slurry from the first liquid supply unit of the manufacturing apparatus into the manufacturing apparatus;
a circulation pump that circulates the slurry between the manufacturing apparatus and the circulation line;
A system for producing fine particles of a metal compound, wherein the circulation pipeline does not include a retention tank. The system for producing fine particles of metal compounds according to claim 11 or 12, characterized in that the second liquid supply unit capable of supplying the second reaction liquid to the inside of the reaction tank is further provided above the stirring blade and the first liquid supply unit in the reaction tank.

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