WO2025196882A1 - Method for producing fine particles of metal compound, and fine particles of metal compound - Google Patents

Abstract

This method for producing fine particles of a metal compound uses a crystallization device provided with: a stirring blade that has a plurality of holes penetrating in a radial direction and that is rotatable around a central axis; a bottomed cylindrical reaction tank capable of concentrically storing the stirring blades inside the reaction tank; a first liquid supply part that is provided to the reaction tank and that is capable of supplying a first reaction liquid to the inside of the reaction tank; and a second liquid supply part that is provided to the stirring blade and that is capable of supplying a second reaction liquid to the inside of the reaction tank, the method involving: supplying the first reaction liquid from the first liquid supply part and supplying the second reaction liquid from the second liquid supply part; and rotating the stirring blade at a circumferential velocity of 25 m/s or more and thereby reacting the first reaction liquid and the second reaction liquid to precipitate fine particles of a metal compound.

Description

METHOD FOR PRODUCING METAL COMPOUND MICROPARTICLES, METAL COMPOUND MICROPARTICLES

The present invention relates to a method for producing metal compound microparticles and metal compound microparticles.

High capacity and high output are required for 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 underway to increase the nickel content in the positive electrode material and reduce the particle size (secondary particle size).

The co-precipitation method is commonly used to manufacture metal hydroxides, the raw material for cathode materials. The more 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 fine particle size to achieve high output. To achieve both high capacity and high output, research is underway to develop technologies that can increase the nickel content and produce fine particles.

Methods for achieving a high nickel content and fine particle size include shortening the residence time of the crystals in the reaction tank and increasing the pH. While this can reduce the secondary particle size, excessive shortening of the residence time or high pH can lead 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 to maintaining crystal quality is the limit to adjustment using the above methods. Here, sphericity is defined as (diameter equivalent to the area circle of the particle's projected image) / (diameter of the smallest circumscribed circle of the particle's projected image).

Research is being conducted into suppressing particle size growth by increasing the stirring and shear forces in the reactor, but there is a need to efficiently transmit high stirring and shear forces to the micro-reaction fields of metal hydroxides, which have extremely 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 efficiently transmit high stirring and shear forces to the micro-reaction fields.

Patent Document 1 discloses that 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% is produced using a pump and a propeller-type rotor as an agitator.
Patent Document 2 discloses a positive electrode active material precursor for lithium ion secondary batteries, which has an average particle size of 3 to 15 μm and a nickel content of up to 30% by mass.
Patent Document 3 discloses that 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 is produced by using a turbine impeller as a stirring blade.

Republished WO2019/117027 Japanese Patent Application Publication No. 2021-136096 International Publication No. 2020/202602

The present invention was made against this background, and aims to provide a method for producing metal compound microparticles that have a high nickel content and are micronized to a level that allows for high capacity and high output sufficient for use as cathode materials for next-generation batteries, as well as metal compound microparticles.

A first aspect of the present invention is a method for producing fine particles of a metal compound, which uses a crystallization apparatus comprising: an agitator blade 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 blade; a first liquid supply unit provided in the reaction vessel and capable of supplying a first reaction liquid to the reaction vessel; and a second liquid supply unit provided in the agitator blade and capable of supplying a second reaction liquid to the reaction vessel; the first reaction liquid is supplied from the first liquid supply unit and the second reaction liquid is supplied from the second liquid supply unit; and the agitator blade is rotated at a peripheral speed of approximately 25 m/s or more, thereby reacting the first reaction liquid with the second reaction liquid and precipitating fine particles of the metal compound.

According to the first aspect of the present invention, it is possible to obtain fine particles of a metal compound having a small average particle size and high sphericity.

A second aspect of the present invention is a method for producing fine particles of a metal compound according to the first aspect, wherein the stirring blade of the crystallization device comprises a cylindrical portion, 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, 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 periphery of the disk portion.

According to the second aspect of the present invention, the second reaction liquid can be supplied to a range close to the inner and outer peripheries of the stirring blades, where high shear forces are present, and fine particles of a metal compound having a small average particle size and high sphericity can be obtained.

A third aspect of the present invention is a method for producing fine particles of a metal compound, wherein the second liquid supply section of the crystallization device according to the second aspect is open downward.

According to the third aspect of the present invention, the second reaction liquid can be supplied to a range close to the inner and outer peripheries of the stirring blades, where high shear forces are present, and fine particles of a metal compound having a small average particle size and high sphericity can be obtained.

A fourth aspect of the present invention is a method for producing fine particles of a metal compound according to the third aspect, characterized in that the cylindrical portion of the crystallization device above the disk portion has the plurality of radially penetrating holes blocked, and a second disk-shaped portion, the outer periphery of which is 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 reduce the power required to rotate the stirring blades and obtain fine particles of a metal compound with a small average particle size and high sphericity.

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

According to the fifth aspect of the present invention, it is possible to reduce the power required to rotate the stirring blades and obtain fine particles of a metal compound with a small average particle size and high sphericity.

A sixth aspect of the present invention is a method 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 of the crystallization apparatus 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 greater.

According to the sixth aspect of the present invention, it is possible to obtain fine particles of a metal compound having a small average particle size and high sphericity.

A seventh aspect of the present invention is a method for producing fine particles of a metal compound according to any one of the first to sixth aspects, characterized in that the crystallization device is provided with a plurality of second liquid supply sections.

According to the seventh aspect of the present invention, the second reaction liquid can be supplied uniformly in the circumferential direction of the disk portion, and fine particles of a metal compound having a small average particle size and high sphericity can be obtained.

An eighth aspect of the present invention is a method for producing fine particles of a metal compound according to any one of the first to seventh aspects, comprising the crystallizer; a circulation pipeline that fluidizes the slurry containing the fine particles discharged from the discharge port of the crystallizer and circulates the slurry from the first liquid supply section of the crystallizer into the crystallizer; and a circulation pump that circulates the slurry between the crystallizer and the circulation pipeline, wherein the circulation pipeline uses a crystallization system having a serpentine bend, and the metal-based raw material fed into the crystallization system contains nickel at a substance ratio of 90% or more.

According to the eighth aspect of the present invention, it is possible to obtain fine particles of a metal compound having a high nickel content, a small average particle size, and high sphericity.

A ninth aspect of the present invention is a method for producing fine particles of a metal compound according to the eighth aspect, characterized in that the pH of the mixture of the first reaction liquid and the second reaction liquid and the residence time of the fine particles in the crystallization system are maintained constant.

According to the ninth aspect of the present invention, it is possible to obtain fine particles of a metal compound having a high nickel content, a small average particle size, and high sphericity.

A tenth aspect of the present invention is a method for producing fine particles of a metal compound according to the eighth or ninth aspect, characterized in that the average particle diameter d50 of the fine particles is adjusted by adjusting the peripheral speed of the stirring blade.

According to the tenth aspect of the present invention, it is possible to obtain metal compound microparticles that have a high nickel content, a small average particle size, and high sphericity. In other words, the average particle size of the resulting metal compound microparticles can be controlled primarily by adjusting the circumferential speed of the agitator blades. In other words, by adjusting the circumferential speed of the agitator blades, it is possible to individually adjust the shear force and circulating flow, enabling agitation in the reaction vessel that is specialized for the transmission of shear force. The major benefit of this improved mechanism is that particle size can be controlled primarily by adjusting the circumferential speed of the agitator blades. Unlike the conventional method of particle size control, which relied on adjusting the residence time and pH value, this method allows particle size to be controlled primarily by adjusting the circumferential speed of the agitator blades, while maintaining constant residence time and pH values under conditions that do not degrade product quality. This improved functionality allows particle size to be controlled while maintaining the residence time and pH value so as not to deteriorate the particle shape, resulting in the production of high-quality metal hydroxides with a high nickel content, a small average particle size, and high sphericity.

An eleventh aspect of the present invention is metal compound microparticles produced by the production method of any one of the first to tenth aspects, having an average particle diameter d50 of 3 μm or less and a nickel mass ratio of 90% or more.

According to the eleventh aspect of the present invention, it is possible to obtain fine particles of a metal compound having high sphericity, a high nickel content, and an average particle diameter of 3 μm or less.

A twelfth aspect of the present invention is the eleventh aspect, wherein the microparticles are microparticles of a metal compound that are microparticles of a ternary metal hydroxide composed of nickel, cobalt, and manganese.

According to the twelfth aspect of the present invention, it is possible to obtain fine particles of a ternary metal hydroxide composed of nickel, cobalt, and manganese, which have high sphericity, a high nickel content, and an average particle diameter of 3 μm or less.

The present invention provides a method for producing a metal compound and metal compound microparticles that have a high nickel content and are microparticulate, enabling high capacity and high output to be achieved to the extent that they can be used as cathode materials for next-generation batteries.

1 is a schematic diagram of a crystallization system according to a first embodiment of the present invention. 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 microparticles 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 microparticles 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. 10 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. 1 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.

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

The crystallization system 10A comprises a crystallizer 4 that mixes multiple raw material solutions to produce particles derived from the raw materials in these multiple raw material solutions, a circulation line Po that is located downstream of the crystallizer 4 and circulates slurry D1 discharged from the discharge outlet 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. Note that in the following description, particles may be referred to as fine particles or 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. The bent portion Pp is not limited to a serpentine shape and may also be spiral-shaped.

The circulation pump 30 is a circulation pump that circulates 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 on the pipe 23 or the pipe 24.

The crystallization device 4 comprises a cylindrical reaction vessel 1 with a bottom and a vertically oriented central axis O1, and a cylindrical agitator Wc. The agitator Wc is rotatable around a hollow rotary shaft 3 extending upward along the central axis O1 from the center of the agitator Wc in a plan view, and is housed inside the reaction vessel 1 with the central axis O1 as the central axis. The rotary shaft 3 rotates due to torque supplied via a belt B from a prime mover M provided outside the crystallization device 4. The prime mover M may be a device that generates rotational power, such as a motor or engine. The belt B that transmits the torque to the rotary shaft 3 may be a chain, gear, or other device capable of transmitting torque. The bottom of the reaction vessel 1 may be flat as shown in the figure, or may be cone-shaped with a downward convexity. An outlet 6 is provided at the top of the reaction vessel 1, allowing slurry containing particles (crystals) produced in the reaction vessel 1 to be discharged to the next process. A pressure indication controller that maintains or adjusts the pressure of the slurry D1 discharged from the discharge port 6 into the pipe 22 is provided on the pipe 22. Details of the mixing blades Wc will be described later.

An inlet 5a is provided at the bottom of the reaction vessel 1, 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 produced by mixing auxiliary materials _SA and S _B supplied from tanks (not shown) that store the auxiliary materials _SA and S _B. The flow rates of the auxiliary materials _SA and S _B of the first reaction liquid L1 are maintained or adjusted by flow indication controllers _FIC2 and _FIC3 . A predetermined amount of the first reaction liquid L1 is supplied to the reaction vessel 1 from the inlet 5a. The supply rate of the first reaction liquid L1 from the inlet 5a can be adjusted to a predetermined amount, for example, by adjusting the rotation speed of the circulation pump 30. A pressure indicator _PI1 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 _SM . 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 produce precipitated and crystallized fine particles of a metal compound. The slurry D1 is a fluid containing these fine particles of the metal compound.

The bending portion Pp is composed of a plurality of straight pipe sections (Po1, Po2, Po3, Po4, Po5, Po6) with an inner diameter of r2 that are arranged at intervals facing substantially the same direction, a plurality of curved pipe sections C ( _C1 , _C2 , _C3 , C4, _C5 ) with an inner diameter of r3 that connect the adjacent plurality of 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 curved pipe section C is separable means that, for example, the curved pipe section _C5 , which 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, flanges (not shown) may be 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 flanges using bolts, nuts, etc. The attachment and detachment method is not limited to this, and as long as the curved pipe section _C5 is freely attachable and detachable, it may also be attached and detached by screwing both ends of the curved pipe section C5 to the left ends of the straight pipe sections Po5 and Po6, without being limited to the method using flanges.
Although the fixed plate 21 is rectangular 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 fixed to 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: 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: 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 Figure 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 piping 22. In this case, the curved pipe section _C2 may be provided with a bellows section that is flexible and bendable, making the curved pipe section _C2 flexible.

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. In other words, 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.

Here, 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 rate 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 can flow without settling within 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 that will 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 easier to analyze the flow 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 this case, the flow analysis may be performed taking into account the different inner diameters.

A conduit connected to a slurry discharge pump 31 is connected to the conduit 23 through which the slurry D1 discharged from the bent portion Pp flows. This conduit extracts the slurry D1 from the conduit 23 and collects it to produce 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 capable 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 the function of extracting the slurry D1 from the conduit 23. For example, an impeller with a controllable rotation speed may be provided in the conduit.
The pressure of the slurry D1 in the pipe 23 immediately after the slurry D1 is drawn out 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 control tank 13 is a component that maintains a unidirectional flow of a refrigerant CW, such as cold water, inside the temperature control tank 13 by a pump (not shown). If at least a portion of a bend Pp is provided in the temperature control tank 13, the refrigerant collides with the straight pipe sections Po1, Po2, Po3, Po4, Po5, and Po6 of the bend Pp. In this case, heat is exchanged between the slurry D1 flowing through the straight pipe sections Po1, Po2, Po3, Po4, Po5, and Po6 of the bend Pp and the refrigerant CW via the components that make up the straight pipe sections Po1, Po2, Po3, Po4, Po5, and Po6. This allows the slurry D1 to be cooled or heated.
1, the straight pipe sections Po1, Po2, Po3, Po4, Po5, and Po6 are arranged 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 arranged substantially perpendicular to the flow direction of the refrigerant CW, and may be arranged at an angle other than perpendicular. Furthermore, heat exchange with the refrigerant CW may occur in the curved pipe section C of the bent section Pp, or heat exchange with the refrigerant CW may occur in both the straight pipe section of the bent section Pp and the curved pipe section C.

Here, the temperature control 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 straight pipe sections Po1, Po2, Po3, Po4, Po5, and Po6. For example, if a heat quantity Q1 is transferred from a slurry D1 having a heat quantity Q flowing through the straight pipe section Po1 to the refrigerant CW through heat exchange, a heat quantity Q2 is transferred from a slurry D1 having a heat quantity (Q-Q1) flowing through the straight pipe section Po2 to the refrigerant CW through heat exchange. Furthermore, if a heat quantity Q3 is transferred from a slurry D1 having a heat quantity (Q-(Q1+Q2)) flowing through the straight pipe section Po3 to the refrigerant CW through 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 the desired amount. The same applies when heating the slurry D1.

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

Furthermore, with this 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 it is approximately half the height of the cylindrical portion 2, but is not limited to this example and may be provided below or above approximately half the height of the cylindrical portion 2. The rotation shaft 3 is fixed to the center of the disk portion 8 in a plan view.
The second disk part 15 is a disk-shaped member provided above the disk part 8, and has a hole in its center in a plan view through which the rotating shaft 3 passes. Except for the hole through which the rotating shaft 3 passes, there are no other holes that pass through the second disk part 15 in the direction of the central axis O1. Therefore, the first reaction liquid L1, the second reaction liquid L2, and their mixture do not enter the inside of the second disk part 15.
The hollow interior of the rotating shaft 3 is a conduit P1. Multiple conduits P2 extend radially from the center toward the outer edge within the disk portion 8. The conduit P1 of the rotating shaft 3 and the conduit P2 of the disk portion 8 are connected to each other. A second reaction liquid L2 is supplied to the rotating shaft 3 of the agitator blade Wc from a tank (not shown) that stores the main raw material S _M and is provided outside the crystallizer 4. The second reaction liquid L2 is supplied to the hollow conduit P1 of the rotating shaft 3 via the rotary joint R and then to the conduit P2 of the disk portion 8. The tip of the conduit P2, located radially outward from the reaction tank 1, opens downward and serves as a liquid supply section (second liquid supply section) 5b from which the second reaction liquid L2 is discharged. Therefore, the disk portion 8 is provided with multiple liquid supply sections 5b spaced apart around the circumference of the disk portion. For example, eight liquid supply sections 5b are provided. The number of liquid supply portions 5b is not limited, but it is desirable 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 We and the center of the liquid supply portion 5b is 2 mm or less. Furthermore, as shown in FIG. 2, if the distance (clearance) between the outer circumferential surface 2o of the cylindrical portion 2 of the impeller We and the inner circumferential surface 1i of the reaction vessel 1 is L3, and the height along the central axis O1 of the impeller We (cylindrical portion 2) is He, the ratio of He to L3, He/L3, is preferably 10 or greater. Furthermore, He/L3 is more preferably 25 or greater. Therefore, even when using a device of a different size than this embodiment, a similar device can be manufactured based on this ratio. The impeller We rotates at a peripheral speed of 5 m/s or greater and 50 m/s or less. Note that the He/L3 ratio 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.

The cylindrical portion 2 of the agitator Wc has a plurality of holes h formed below the disk portion 8, penetrating radially through the cylindrical portion 2. These holes h allow the first reaction liquid L1, the second reaction liquid L2, or a mixture thereof to flow through them. 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 agitator Wc, or from the outside to the inside of the agitator Wc, through the plurality of holes h. In this way, when the plurality of holes h penetrating radially through the cylindrical portion 2 are formed below the disk portion 8, the agitator Wc can be rotated with less power than when the plurality of holes h are formed on both the upper and lower sides of the disk portion 8.
Such a cylindrical portion 2 may be formed by processing a cylindrical portion 2 before processing, which has holes h evenly distributed across the height of the cylindrical portion 2, so as to close the holes h above the disk portion 8, thereby forming a cylindrical portion 2 in which 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 that holes h are provided only below the disk portion 8, and no processing is performed to provide holes h above the disk portion 8.

In a crystallizer 4 equipped with such an agitator Wc, a predetermined amount of first reaction liquid L1 is supplied to the reaction tank 1 through the inlet 5a. The amount of first reaction liquid L1 supplied may be enough to fill the reaction tank 1 (full state), or may be enough to press the first reaction liquid L1 against the inner circumferential surface 1i of the reaction tank 1 due to centrifugal force generated by the first reaction liquid L1 as the agitator W rotates and the first reaction liquid L1 undergoes circular motion about 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. The following description will be given assuming that the first reaction liquid L1 is supplied to the extent that the reaction tank 1 is full. Alternatively, the reaction may be carried out in the reaction tank 1 after the first reaction liquid L1 is supplied to an extent that the first reaction liquid L1 reaches the above-mentioned liquid-filled state or liquid film formation state and then the supply of the first reaction liquid L1 is stopped (batch method described later), or the reaction may be carried out continuously in the reaction tank 1 while maintaining the first reaction liquid L1 at a flow rate that reaches the above-mentioned liquid-filled state or liquid film formation state (continuous method described later).
For example, by providing an opening adjustment valve (not shown) at the outlet 6 and adjusting the opening of this opening 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 agitator Wc is rotated and the second reaction liquid L2 is discharged from the liquid supply section 5b along the inner surface 2i of the cylindrical portion 2 of the agitator 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 surface 2i of the cylindrical portion 2 of the agitator Wc comes into contact with the first reaction liquid L1 that is rotating in conjunction with the rotation of the agitator Wc near the inner surface 2i of the cylindrical portion 2 of the agitator Wc in the reaction vessel 1 filled with the first reaction liquid L1. This contact between the first reaction liquid L1 and the second reaction liquid L2 causes a reaction to occur, producing particles.

In this case, the second reaction liquid L2 is supplied to the first reaction liquid L1 from the liquid supply portion 5b of the stirring impeller Wc, which is rotating at a peripheral speed of 5 m/s or more and 50 m/s or less, thereby allowing the second reaction liquid L2 to be uniformly mixed with the first reaction liquid L1.

Here, due to the centrifugal force generated in the mixture of the first reaction liquid L1 rotating with the rotation of the agitator impeller We and the second reaction liquid L2 discharged from the liquid supply portion 5b of the agitator impeller We, which rotates at a peripheral speed of 5 m/s to 50 m/s, the first reaction liquid L1, the second reaction liquid L2, and the mixture (hereinafter sometimes collectively referred to as the mixture) move radially outward from the cylindrical portion 2 of the agitator impeller We, pass through multiple holes h provided in the cylindrical portion 2 of the agitator impeller We, collide with the inner surface 1i of the reaction vessel 1, and then move vertically along the inner surface 1i of the reaction vessel 1. The mixture, which has moved primarily downward, is attracted by the radially outward flow caused by the centrifugal force generated by the rotation of the agitator impeller We, passes through multiple holes h provided in the cylindrical portion 2 of the agitator impeller We, collide with the inner surface 1i of the reaction vessel 1, and then moves vertically along the inner surface 1i of the reaction vessel 1, creating convection. Here, when the mixed liquid passes through the multiple holes h, the effect of the throttle flow path causes the mixed liquid to accelerate radially outward, so the radially outward flow velocity of the mixed liquid is highest near the multiple holes h. Furthermore, a circumferential shear force is applied to the mixed liquid present between the outer peripheral surface 2o and inner peripheral surface 2i of the cylindrical portion 2 of the agitator impeller Wc, which rotates at a peripheral speed of 5 m/s to 50 m/s, and the fixed inner peripheral surface 1i of the 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 agitator impeller Wc. The shear force applied to the mixed liquid is a major factor in determining the particle size and uniformity of the resulting particles. In particular, the greater the applied shear force, the more fine particles can be obtained.

In the crystallization apparatus 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 agitator Wc and the center of the liquid supply section 5b is 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 agitator Wc first comes into contact with the first reaction liquid L1 rotating in association with the rotation of the agitator Wc near the inner circumferential surface 2i of the cylindrical section 2 of the agitator Wc, maximum shear force is applied in addition to the radially outward flow due to centrifugal force and the effect of the throttle flow channel. Therefore, the region with the greatest applied shear force can be used as the reaction initiation point. Specifically, the reaction initiation point can be formed in a region close to the inner circumferential surface 2i and outer circumferential surface 2o of the cylindrical section 2 of the agitator 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 multiple holes h. Therefore, the shear force promotes the mixing of the first reaction liquid L1 and the second reaction liquid L2 at the reaction initiation point. Therefore, more uniform mixing of the first reaction liquid L1 and the second reaction liquid L2 is initiated from the reaction initiation point, and the mixing and reaction occur in a reaction field where the reaction occurs along the flow of the mixed liquid, thereby producing fine particles with a uniform diameter. Here, the reaction initiation point refers to the region where the reaction starts, and the reaction field refers to the entire field where the reaction occurs. Therefore, the reaction initiation point is included in the reaction field.
2 may be provided on the inner peripheral surface of the reaction vessel 1 corresponding to the upper part of the stirring blade Wc. The baffle 7 has the effect of suppressing the generation of vortices and promoting the stirring of the mixed liquid when the reaction vessel 1 is filled with 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, the baffle 7 does not need to be provided.
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 vessel 1 where the rotating shaft 3 is inserted, and a completely liquid-filled state with no gas phase is achieved, the generation of vortices 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.

In addition, the same effect can be obtained when a liquid film is formed rather than when the container is filled with liquid.

The crystallization system 10A including this crystallizer 4 makes it possible to individually adjust the shear force, the circulation volume of the first reaction liquid L1, and the residence time of the slurry, which all affect the particle quality of the reaction product in the crystallizer 4, such as particle size, particle size distribution, and sphericity, thereby further improving the controllability of particle quality.

The crystallizer 4 of the 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 impeller Wc can be controlled.
The control unit CON is a computer that controls the rotation speed of the prime mover M based on operations 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., capable of implementing the above-described control. The details of the control by the control unit CON may be defined by software that can be changed or updated by the user. As shown in FIGS. 1 and 2 , the control unit CON is electrically or electronically connected to the prime mover M. The control unit CON may also include a rotation speed sensor that measures the rotation speed of the agitator 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, if the prime mover M is a motor, the control unit CON may control the motor rotation speed by controlling the motor's drive voltage. If the prime mover M is an engine, the control unit CON may control the engine rotation speed by controlling the amount of fuel supplied to the engine.

Using this crystallization system 10A, the residence time of the crystals in the crystallization system 10A including the reaction vessel 1 and the pH of the mixture of the first reaction liquid L1 and the second reaction liquid L2 in the reaction vessel 1 were fixed or maintained at constant conditions, and the average particle diameter d50 of the microparticles obtained was measured when the peripheral speed of the agitator impeller Wc was changed. As a result, the average particle diameter d50 of the microparticles obtained when the peripheral speed of the agitator impeller 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 impeller 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 impeller 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. From Figure 3, it was confirmed that as the peripheral speed of the stirring blade Wc increases, fine particles with a smaller average particle diameter d50 are obtained. From Figure 3, it was also confirmed that at peripheral speeds of 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, at which the average particle diameter d50 is 3 μm or less.

From the results shown in Figure 3, it was confirmed that by using the crystallization system 10A and the method for producing fine particles in which the peripheral speed of the stirring blade Wc is set to approximately 25 m/s or more, fine particles having an average particle diameter d50 of 3 µm or less can be obtained.
The microparticles obtained in Figure 3 are a metal compound 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. Here, a substance amount ratio of 90% or more means that, when the total substance amount of nickel, cobalt, and manganese is 100, the substance amount of nickel is 90% or more. Therefore, it was confirmed that, despite a high nickel content, minute microparticles with an average particle diameter 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.

The results in Figure 3 were obtained when the crystallization system 10A was operated in a continuous mode. The continuous mode refers to an operating mode in which the main raw material S _M and the auxiliary raw materials S _A and S _B are continuously supplied during operation of the crystallization system 10A shown in Figure 1, and the resulting slurry D1 containing fine particles is continuously discharged from the crystallization system 10A to the outside. Since the nickel mass ratio of the ternary metal hydroxide composed of nickel, cobalt, and manganese produced in the crystallization system 10A is 90% or more, the nickel mass ratio of the metal 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 predetermined amounts 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 the operation of the crystallization system 10A is started, 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 microparticles obtained by operating crystallization system 10A in this continuous mode so that the peripheral speed of the agitator blade Wc was approximately 25 m/s or more. It can be seen that the sphericity of the particles was high, averaging 0.85 or more. In this case, the average particle diameter d50 was 1.32 μm. Figure 5 is an electron microscope photograph of microparticles obtained using conventional technology that does not use agitator blades shaped like the agitator blade Wc of crystallization system 10A. It can be seen that the sphericity of the microparticles is clearly lower than that of the microparticles 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. Similar to the microparticles obtained in a continuous mode shown in Figure 4, even when operated in a batch mode, the sphericity of the particles averages 0.9 or more, demonstrating that highly spherical microparticles can be obtained. Furthermore, compared to the continuous mode, the uniformity of the particle size distribution is significantly improved, achieving a span of (d90 - d10)/d50 = 0.7 or less. The average particle diameter d50 in this case was 1.40 μm.

By using a crystallization system 10A including a crystallizer 4 equipped with a control unit CON capable of controlling the circumferential speed of the agitator blades Wc as described above, it is possible to produce ternary metal hydroxide microparticles composed of nickel, cobalt, and manganese, which have high sphericity, a high nickel content of 90% or more by mass, and a minute average particle diameter d50 of 3 μm or less. Furthermore, the average particle diameter d50 of the resulting metal compound microparticles can be controlled by adjusting the circumferential speed of the agitator blades Wc under the control of the control unit CON. In other words, by providing a control unit CON capable of controlling the circumferential speed of the agitator blades Wc and enabling the shear force and circulation flow to be adjusted separately, agitation specialized for the transmission of shear force is possible in the reaction vessel 1. In other words, the shear force applied to the mixed liquid in the reaction vessel 1 is adjusted by adjusting the circumferential speed of the agitator blades Wc, and the circulation flow is adjusted by adjusting the rotation speed of the circulation pump 30 (Figure 1). The major benefit of this mechanical improvement is that particle size can be controlled primarily by adjusting the circumferential speed of the agitator blades Wc. Unlike conventional particle size control, which relied on adjusting residence time and pH value, this technology allows particle size to be controlled primarily by adjusting the peripheral speed of the stirring blades Wc, while maintaining constant residence time and pH value settings that do not degrade product quality. This dramatically improves particle size control performance. This improved functionality allows particle size to be controlled while maintaining residence time and pH values that do not cause deterioration of particle shape, resulting in the production of high-quality metal hydroxide with a high nickel content, 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 modification 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 We of crystallization system 10A, and in that the bent portion Pp is not located inside the temperature control tank 13.

As shown in Figure 7, the agitator Wd differs from the agitator Wc in that the disk portion 8 is located at the upper end of the cylindrical portion 2. Furthermore, the height of the cylindrical portion 2 is approximately half that of the agitator Wc. Using a crystallizer 4d equipped with such an agitator Wd can achieve the same effects as the crystallizer 4 equipped with the agitator Wc. Furthermore, because the cylindrical portion 2 is not located above the disk portion 8, the agitator Wd can be made lighter than the agitator Wc. Furthermore, because the agitator Wd can have a simple structure, it can be operated with less power than the agitator Wc, which is expected to improve energy efficiency of the crystallizer 4d and make it easier to manufacture the agitator Wd. Furthermore, because the height of the cylindrical portion 2 is kept short, the crystallizer 4d can be made more compact.

The use of the crystallization system 10B according to the first modified example including such a crystallizer 4d makes it possible to produce fine particles of a ternary metal hydroxide composed of nickel, cobalt, and manganese, which have 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, just as in the case of using 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, similarly to the crystallization system 10A.

<Second Modification of First Embodiment>
8 is a schematic diagram showing a crystallization system 10C according to a second modification 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.

While the crystallization systems 10A and 10B are configured to be operated continuously, the crystallization system 10C is configured to be operated batchwise. In this case, a larger device capacity can be secured than when the bent portion Pp is used. Therefore, in a batchwise operation in which the system forming the crystallization system 10C is closed to the outside during operation, a larger number of microparticles can be produced in a single operation. Therefore, efficient microparticle production is possible. Even when operating this crystallization system 10C in a batchwise manner, it is possible to produce microparticles with high sphericity, a high nickel content of 90% or more in terms of substance mass ratio, and an average particle diameter d50 of 3 μm or less, as shown in FIG. 6 . Furthermore, when producing microparticles in a batchwise manner, the uniformity of the particle size distribution is significantly improved compared to a continuous method, 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 also 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 within the system and improve the production volume per unit volume. In principle, the slurry has fluidity and the concentration can be increased to a level that allows it to be pumped. A filter, a centrifuge, a thickener, or the like can be used as the concentrator 11. When using this crystallization system 10D, it is also possible to produce fine particles with high sphericity, a high nickel content of 90% or more in terms of substance amount, 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 also be improved.

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

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 includes designs that do not deviate from the gist of the invention, as well as combinations of the embodiment and its variations.

We can provide a manufacturing method for metal compounds and metal compound microparticles that have a high nickel content and are micronized, enabling high capacity and high output sufficient for use as cathode materials in next-generation batteries.

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

Claims (12)

a stirring blade having a plurality of holes penetrating in the radial direction and rotatable around a central axis;
a cylindrical reaction vessel with a bottom that can accommodate the stirring blade concentrically therein;
a first liquid supply unit provided in the reaction tank and capable of supplying a first reaction liquid into the reaction tank;
a second liquid supply unit provided on the stirring blade and capable of supplying a second reaction liquid into the reaction tank;
A crystallizer comprising:
supplying the first reaction liquid from the first liquid supply unit and the second reaction liquid from the second liquid supply unit;
A method for producing fine particles of a metal compound, comprising: rotating the stirring blade at a peripheral speed of approximately 25 m/s or more to react the first reaction liquid with the second reaction liquid, thereby precipitating fine particles of the metal compound. The stirring blade of the crystallizer is
a cylindrical portion;
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,
2. The method for producing metal compound microparticles described in claim 1, wherein 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 method for producing fine particles of a metal compound according to claim 2, wherein the second liquid supply section of the crystallization device opens downward. The method for producing fine particles of a metal compound according to claim 3, wherein the cylindrical portion of the crystallization device above the disk portion has a plurality of holes penetrating in the radial direction blocked, and a second disk-shaped portion, the outer edge of which is fixed to the inner circumferential surface of the cylindrical portion, is provided at the upper end of the cylindrical portion. The method for producing fine particles of a metal compound according to claim 3, wherein the disk portion of the crystallization device is provided at the upper end of the cylindrical portion. The method for producing fine particles of a metal compound according to any one of claims 2 to 5, wherein He/L3 is 10 or greater, where L3 is the clearance between the outer peripheral surface of the cylindrical portion of the crystallization device and the inner peripheral surface of the reaction tank, and He is the height of the cylindrical portion. The method for producing fine particles of a metal compound according to any one of claims 1 to 5, wherein the crystallization device has a plurality of second liquid supply sections. The crystallizer;
a circulation pipe that causes the slurry containing the fine particles discharged from the discharge port of the crystallizer to flow and circulates the slurry from the first liquid supply part of the crystallizer into the crystallizer;
a circulation pump that circulates the slurry between the crystallizer and the circulation line;
6. The method for producing fine particles of a metal compound according to claim 1, wherein the circulation pipeline uses a crystallization system having a serpentine bend, and nickel accounts for 90% or more of the metal-based raw materials fed into the crystallization system in terms of substance amount ratio. The method for producing fine particles of a metal compound according to claim 8, wherein the pH of the mixture of the first reaction liquid and the second reaction liquid and the residence time of the fine particles in the crystallization system are maintained constant. The method for producing fine particles of a metal compound according to claim 8, wherein the average particle diameter d50 of the fine particles is adjusted by adjusting the peripheral speed of the stirring blade. Fine particles of a metal compound produced by the production method described in any one of claims 1 to 5, having an average particle diameter d50 of 3 μm or less and a nickel mass ratio of 90% or more. The metal compound microparticles described in claim 11, wherein the microparticles are microparticles of a ternary metal hydroxide composed of nickel, cobalt, and manganese.