Fluidized bed reactor and method for regenerating lithium precursor using the same

Abstract

The method for regenerating a lithium precursor of the present invention includes preparing a positive electrode active material powder including lithium composite oxide particles and having different particle sizes, reducing the positive electrode active material powder in a fluidized bed reactor including a reactor body whose diameter decreases stepwise or gradually from top to bottom to produce a pre-precursor mixture, and recovering a lithium precursor from the pre-precursor mixture.

Description

[Technical Field]

[0001] The present invention relates to a fluidized bed reactor and a method for regenerating lithium precursors using the same, and more specifically, to a fluidized bed reactor and a method for regenerating lithium precursors from waste lithium-containing compounds using the same. [Background technology]

[0002] Rechargeable batteries are batteries that can be repeatedly charged and discharged, and with the development of the information and communication and display industries, they have been widely applied to portable electronic communication devices such as camcorders, mobile phones, and laptop computers. Examples of rechargeable batteries include lithium-ion batteries, nickel-cadmium batteries, and nickel-metal hydride batteries. Among these, lithium-ion batteries have been actively developed and applied due to their high operating voltage and energy density per unit weight, as well as their advantages in charging speed and weight reduction.

[0003] A lithium secondary battery may include an electrode assembly comprising a positive electrode, a negative electrode, and a separator, and an electrolyte that impregnates the electrode assembly. The lithium secondary battery may further include an outer packaging material, for example, a pouch, that houses the electrode assembly and the electrolyte.

[0004] A lithium metal oxide can be used as the positive electrode active material for the lithium secondary battery. The lithium metal oxide may further contain transition metals such as nickel, cobalt, and manganese.

[0005] The lithium metal oxide used as the positive electrode active material can be produced by reacting a lithium precursor with a nickel-cobalt-manganese (NCM) precursor containing nickel, cobalt, and manganese.

[0006] Because the aforementioned high-cost valuable metals are used in the positive electrode active material, the manufacturing of the positive electrode material accounts for more than 20% of the manufacturing cost. Furthermore, in recent years, with growing concern for environmental protection, research into recycling methods for positive electrode active materials is progressing. For the recycling of the positive electrode active material, it is necessary to regenerate the lithium precursor from waste positive electrodes with high efficiency and high purity. [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] One objective of the present invention is to provide a fluidized bed reactor for recovering lithium precursors from lithium-containing compounds in high purity and high yield, and a method for regenerating lithium precursors using the same. [Means for solving the problem]

[0008] A method for regenerating a lithium precursor according to an embodiment of the present invention may include the step of preparing a positive electrode active material powder comprising lithium composite oxide particles having different particle sizes. The positive electrode active material powder is reduced in a fluidized bed reactor having a reactor body in which the diameter decreases stepwise or gradually from top to bottom to produce a preliminary precursor mixture. Then, a lithium precursor is recovered from the preliminary precursor mixture.

[0009] In exemplary embodiments, the positive electrode active material mixture comprises a first active material powder, a second active material powder, and a third active material powder having different particle sizes, and the reactor body may include a first region where the first active material powder is fluidized, a second region where the second active material powder is fluidized, and a third region where the third active material powder is fluidized.

[0010] In an exemplary embodiment, the first region, the second region, and the third region can be arranged sequentially from the top of the reactor body.

[0011] In exemplary embodiments, the diameter of the first region may be greater than the diameter of the second region, and the diameter of the second region may be greater than the diameter of the third region.

[0012] In exemplary embodiments, the ratio of the diameter of the first region to the diameter of the third region may be 4 to 16.

[0013] In exemplary embodiments, the ratio of the diameter of the second region to the diameter of the third region may be 2 to 4.

[0014] In exemplary embodiments, the particle size of the first active material powder may be smaller than that of the second active material powder, and the particle size of the second active material powder may be smaller than that of the third active material powder.

[0015] In exemplary embodiments, the particle size of the first active material powder may be less than 10 μm, the particle size of the second active material powder may be 10 to 100 μm, and the particle size of the third active material powder may be 100 μm or more.

[0016] In exemplary embodiments, the preparation of the preliminary precursor mixture may include injecting a reducing gas into the fluidized bed reactor.

[0017] In exemplary embodiments, the minimum flow velocity of the reducing gas within the first region may be less than or equal to the terminal velocity of the first active material powder.

[0018] In exemplary embodiments, the maximum flow velocity of the reducing gas within the second region may be greater than or equal to the minimum fluidization rate of the second active material powder, and the maximum flow velocity of the reducing gas within the third region may be greater than or equal to the minimum fluidization rate of the third active material powder.

[0019] In an exemplary embodiment, the reducing gas can be injected into the fluidized bed reactor at a flow rate of 8 to 18 cm / s.

[0020] In an exemplary embodiment, it may include a first connecting portion that connects the first region and the second region and has a diameter decreasing from the first region to the second region, and a second connecting portion that connects the second region and the third region and has a diameter decreasing from the second region to the third region.

[0021] In an exemplary embodiment, the first connecting portion and the second connecting portion may further include gas injection ports located on the side surface.

[0022] In an exemplary embodiment, the gas injection ports can be arranged to incline towards the side surface upwardly with respect to the reactor main body.

[0023] In an exemplary embodiment, the angle formed by the side surfaces of the first connecting portion and the second connecting portion and the gas injection ports may be 45 to 90°.

[0024] The fluidized bed reactor for reducing a positive electrode active material according to an embodiment of the present invention includes a reactor main body whose diameter decreases stepwise or gradually from the upper part to the lower part, an active material injection port that includes lithium composite oxide particles and into which a plurality of active material powders having different particle sizes are injected within the reactor main body, and a gas injection port that is located at the lower part of the reactor main body and into which a reducing gas for fluidizing the active material powder is injected.

[0025] In an exemplary embodiment, the fluidized bed reactor for reducing a positive electrode active material of the present invention may include a first connecting portion that connects the first region and the second region and has a diameter decreasing from the first region to the second region, and a second connecting portion that connects the second region and the third region and has a diameter decreasing from the second region to the third region.

[0026] In an exemplary embodiment, the first connecting portion and the second connecting portion may further include gas injection ports located on the side surface.

Advantages of the Invention

[0027] According to the exemplary embodiments described above, the lithium precursor regeneration method of the present invention allows for the reduction treatment of active material powders having different particle sizes in a fluidized bed reactor containing a reactor body in which the diameter decreases stepwise or progressively from top to bottom. This makes it easier to obtain lithium precursors in high yield and high purity.

[0028] Furthermore, by changing the diameter of the reactor, temperature deviations due to location within the reactor can be reduced. This allows for smoother fluidization of the positive electrode active material particles, enabling uniform mixing and reduction throughout the entire reactor.

[0029] Furthermore, the fluidized bed reactor may further include gas injection ports on its side. These gas injection ports can prevent the active material powder from accumulating on the side of the fluidized bed reactor. This allows for a further improvement in the recovery efficiency of the lithium precursor. [Brief explanation of the drawing]

[0030] [Figure 1] Figure 1 is a schematic flowchart illustrating a method for regenerating a lithium precursor according to an exemplary embodiment. [Figure 2] Figure 2 is a schematic diagram showing a fluidized bed reactor for reducing positive electrode active material according to an exemplary embodiment. [Figure 3] Figure 3 is a schematic diagram showing a fluidized bed reactor for reducing positive electrode active material according to an exemplary embodiment. Forms for making an invention

[0031] Embodiments of the present invention utilize a fluidized bed reactor, which includes a reactor body whose diameter decreases in a stepwise or gradual manner from top to bottom, to recover a lithium precursor from a positive electrode active material. This allows for a further improvement in the recovery efficiency of the lithium precursor.

[0032] The embodiments of the present invention will be described in detail below with reference to the attached drawings. However, these embodiments are merely illustrative and do not limit the present invention.

[0033] As used herein, the term “precursor” is used to comprehensively refer to compounds containing a specific metal in order to provide a specific metal contained in an electrode active material.

[0034] Figure 1 is a schematic flowchart illustrating a method for regenerating a lithium precursor according to an exemplary embodiment.

[0035] According to an exemplary embodiment, a positive electrode active material powder can be prepared that comprises lithium composite oxide particles having different particle sizes (e.g., step S10).

[0036] The positive electrode active material powder may include lithium composite oxide particles obtained or recycled from electrical or chemical elements. The positive electrode active material powder may also include various lithium composite oxide particles such as lithium oxide, lithium carbon oxide, and lithium hydroxide.

[0037] The positive electrode active material powder may include lithium composite oxide particles obtained or recycled from a waste lithium secondary battery. The waste lithium secondary battery may include an electrode assembly comprising a positive electrode, a negative electrode, and a separator membrane interposed between the positive electrode and the negative electrode. The positive electrode and the negative electrode may each include a positive electrode current collector and a positive electrode active material layer and a negative electrode active material layer coated on the negative electrode current collector, respectively.

[0038] For example, the positive electrode active material contained in the positive electrode active material layer may include lithium composite oxide particles containing lithium and a transition metal.

[0039] In some embodiments, the positive electrode active material may include lithium composite oxide particles represented by the following chemical formula 1.

[0040] [Chemical formula 1] Li x M1 a M2 b M3 c O y

[0041] In chemical formula 1, M1, M2 and M3 may be transition metals selected from Ni, Co, Mn, Na, Mg, Ca, Ti, V, Cr, Cu, Zn, Ge, Sr, Ag, Ba, Zr, Nb, Mo, Al, Ga, or B. <x≦1.2、2≦y≦2.2、0<a<1、0<b<1、0<c<1、0<a+b+c≦1であってもよい。

[0042] In some embodiments, the positive electrode active material may include NCM-based lithium composite oxide particles containing nickel, cobalt, and manganese. The NCM-based lithium composite oxide can be produced by reacting a lithium precursor and an NCM precursor (e.g., an NCM oxide) with each other, for example, by a coprecipitation reaction.

[0043] However, the embodiments of the present invention can be applied not only to cathode materials containing NCM-based lithium composite oxide particles, but also to lithium-containing lithium composite oxide cathode materials.

[0044] For example, the positive electrode can be separated and recovered from the waste lithium secondary battery. The positive electrode includes a positive electrode current collector (e.g., aluminum (Al)) and a positive electrode active material layer, and the positive electrode active material layer may include a conductive material and a binder together with the positive electrode active material.

[0045] The conductive material may include, for example, carbon-based materials such as graphite, carbon black, graphene, and carbon nanotubes.

[0046] The binder may include, for example, resin substances such as vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidene fluoride (PVDF), polyacrylonitrile, and polymethyl methacrylate.

[0047] In some exemplary embodiments, the positive electrode active material powder can be prepared by separating the positive electrode from the waste lithium secondary battery and grinding the separated positive electrode.

[0048] For example, the grinding can be carried out using a hammer mill, shredder, cut crusher, impact crusher, etc. In this case, the positive electrode active material powder can be prepared in powder form by grinding, and the positive electrode active material powder may contain particles having different particle sizes.

[0049] For example, the positive electrode active material powder may have a multimodal particle size distribution. For example, a multimodal particle size distribution may mean that there are multiple main peaks in the particle size distribution diagram. In this case, the particle size of the positive electrode active material powder may be about 1 to 100 μm.

[0050] For example, the positive electrode active material powder may include a first active material powder, a second active material powder, and a third active material powder having different particle sizes. For example, the particle size of the first active material powder may be smaller than that of the second active material powder, and the particle size of the second active material powder may be smaller than that of the third active material powder.

[0051] For example, particles with a particle size of less than approximately 10 μm contained in the positive electrode active material powder can be defined as the first active material powder, particles with a particle size of approximately 10 to 100 μm can be defined as the second active material powder, and particles with a particle size of approximately 100 μm or more can be defined as the third active material powder.

[0052] In some embodiments, the recovered positive electrode may be heat-treated before grinding. This can facilitate the desorption of the positive electrode current collector during the grinding process and at least partially remove the binder and conductive material. The temperature of the heat treatment may be, for example, about 100 to 500°C, preferably about 350 to 450°C.

[0053] For example, the positive electrode current collector can be removed by immersing the separated positive electrode in an organic solvent. The positive electrode current collector can be removed from the separated positive electrode by centrifugation, and the positive electrode active material mixture can be selectively extracted by removing the positive electrode current collector.

[0054] Through the aforementioned process, the positive electrode active material mixture can be obtained in which positive electrode current collector components such as aluminum are substantially completely separated and removed, and the content of carbon-based components derived from the carbon-based conductive material and binder is removed or reduced.

[0055] According to an exemplary embodiment, a preliminary precursor mixture can be prepared from the cathode active material powder (e.g., step S20).

[0056] In some embodiments, the positive electrode active material powder can be subjected to hydrogen reduction treatment to produce a preliminary precursor mixture. For example, the hydrogen reduction treatment can be carried out in a fluidized bed reactor including a reactor body in which the diameter decreases stepwise or gradually from top to bottom. For example, the positive electrode active material powder can be introduced into the fluidized bed reactor and a reducing gas can be injected from the bottom of the fluidized bed reactor. For example, the reducing gas may be hydrogen gas. The structure of the fluidized bed reactor and the reactions within the fluidized bed reactor will be described later.

[0057] The reducing gas can form a cyclone from the bottom of the fluidized bed reactor, and the preliminary precursor mixture can be generated in contact with the active material powder.

[0058] For example, the carrier gas can be mixed and injected from the bottom of the fluidized bed reactor along with the reducing gas. This allows the fluidized bed to promote gas-solid mixing and accelerate the reaction, facilitating the formation of the reaction bed of the preliminary precursor mixture within the fluidized bed reactor. The carrier gas may include, for example, an inert gas such as nitrogen (N2) or argon (Ar).

[0059] The preliminary precursor mixture may include the hydrogen reduction reaction product of the lithium-transition metal oxide contained in the active material powder. When an NCM-based lithium oxide is used as the lithium-transition metal oxide, the preliminary precursor mixture may include a preliminary lithium precursor and a transition metal-containing reaction product.

[0060] The aforementioned pre-lithium precursor may include lithium hydroxide, lithium oxide, and / or lithium carbon. According to an exemplary embodiment, since the pre-lithium precursor is obtained by a hydrogen reduction reaction, the mixed content of lithium carbon can be reduced.

[0061] The transition metal-containing reactant may include Ni, Co, NiO, CoO, MnO, and the like.

[0062] The hydrogen reduction reaction can be carried out at approximately 400 to 700°C, preferably 450 to 550°C.

[0063] According to an exemplary embodiment, after collecting the preliminary precursor mixture, a washing treatment can be performed (for example, step S30).

[0064] Through the aforementioned water washing process, the preliminary lithium precursor can be converted into a lithium precursor substantially composed of lithium hydroxide. For example, lithium oxide and lithium carbon mixed in the preliminary lithium precursor can be converted into lithium hydroxide by reacting with water or removed by washing with water. This makes it possible to produce a high-purity lithium precursor converted into the desired form of lithium hydroxide.

[0065] The aforementioned preliminary lithium precursor can react with water and dissolve to produce a substantially aqueous lithium hydroxide solution.

[0066] The transition metal-containing reactant contained in the preliminary precursor mixture can precipitate without dissolving or reacting in water after the washing treatment. This allows the transition metal-containing reactant to be separated by filtration, thereby obtaining a lithium precursor containing high-purity lithium hydroxide.

[0067] In some embodiments, the washing process can be carried out under conditions where carbon dioxide (CO2) is excluded. For example, by performing the washing process in a CO2-free atmosphere (e.g., an air atmosphere from which CO2 has been removed), the regeneration of lithium carbon oxide can be prevented.

[0068] In one embodiment, a CO2-free atmosphere can be formed by purging the water provided during the washing process with a CO2-deficient gas (for example, nitrogen purging).

[0069] In some embodiments, the precipitated transition metal-containing reaction product can be treated with an acid solution to form precursors in the form of salts of each transition metal. In one embodiment, sulfuric acid can be used as the acid solution. In this case, NiSO4, MnSO4, and CoSO4 can be recovered as the transition metal precursors, respectively.

[0070] As mentioned above, the preliminary precursor mixture produced by hydrogen reduction can be washed with water to obtain a lithium precursor that is substantially composed of lithium hydroxide. This prevents the by-production of other forms of lithium precursors, such as lithium carbon dioxide, and allows for the production of a higher-capacity, longer-lived cathode active material.

[0071] The lithium precursor may include lithium hydroxide (LiOH), lithium oxide (Li2O), or lithium carbon oxide (Li2CO3). From the viewpoint of charge / discharge characteristics, lifespan characteristics, and high-temperature stability of lithium secondary batteries, lithium hydroxide is advantageous as a lithium precursor. For example, lithium carbon oxide may undergo deposition reactions on the separation membrane, weakening its lifespan stability.

[0072] Figures 2 and 3 are schematic diagrams illustrating a fluidized bed reactor for reducing positive electrode active material according to an exemplary embodiment.

[0073] Referring to Figure 2, the fluidized bed reactor 100 for reducing positive electrode active material according to the present invention may include a reactor body 110 whose diameter decreases in a stepwise or gradual manner from top to bottom, an active material inlet 103 into which a plurality of active material powders 50, 60, 70 containing lithium composite oxide particles and having different particle sizes are injected, and a gas inlet 105 located in the lower part of the reactor body 110 into which a reducing gas is injected to fluidize the active material powders 50, 60, 70.

[0074] According to some exemplary embodiments, the positive electrode active material powders 50, 60, and 70 may include a first active material powder 50, a second active material powder 60, and a third active material powder 70 having different particle sizes from each other.

[0075] For example, multiple active material powders 50, 60, and 70 can be fluidized within the reactor body 110. For example, the reactor body 110 can include multiple regions with different diameters, each of which is fluidized.

[0076] For example, the larger particle size third active material powder 70 can be fluidized in the lower part of the reactor body 110, while the smaller particle size first active material powder 50 can be fluidized in the upper part of the reactor body 110.

[0077] According to some embodiments, the reactor body 110 may include a first region 111 in which the first active material powder 50 is fluidized, a second region 112 in which the second active material powder 60 is fluidized, and a third region 113 in which the third active material powder 70 is fluidized.

[0078] This effectively prevents problems such as small-particle-sized active material powders scattering and flowing out, or large-particle-sized active material powders not being sufficiently fluidized, during the process of fluidizing the positive electrode active material mixture containing multiple active material powders having different particle sizes.

[0079] Furthermore, by changing the reactor diameter, temperature variations within the reactor can be reduced. This facilitates the fluidization of the positive electrode active material particles, enabling uniform mixing of particles throughout the reactor. As a result, excellent reaction efficiency can be achieved even with particle mixtures having different particle size distributions.

[0080] For example, the diameter D1 of the first region 111 may be larger than the diameter D2 of the second region 112, and the diameter D2 of the second region 112 may be larger than the diameter D3 of the third region 113.

[0081] In this case, the particle size of the first active material powder 50 fluidized in the first region 111 may be smaller than the particle size of the second active material powder 60 fluidized in the second region 112, and the particle size of the second active material powder 60 fluidized in the second region 112 may be larger than the particle size of the third active material powder 70 fluidized in the third region 113.

[0082] For example, the flow rate of the reducing gas injected into the fluidized bed reactor can be inversely proportional to the square of the diameter of each region. Therefore, the flow rate of the reducing gas may be slower in the first region 111 than in the second region 112, and slower in the second region 112 than in the third region 113. This allows the first active material powder 50 with small particle size to be easily fluidized in the first region 111, and the third active material powder 70 with large particle size to be easily fluidized in the third region 113.

[0083] According to some exemplary embodiments, the ratio D1 of the diameter of the first region 111 to the diameter D3 of the third region 113 may be 5 to 10. For example, the ratio D2 of the diameter of the second region 112 to the diameter D3 of the third region 113 may be 2 to 4.

[0084] For example, by satisfying the aforementioned diameter ratio range, the fluidization of the first active material powder 50, the second active material powder 60, and the third active material powder 70 can be made easier. This can further improve the recovery efficiency of the lithium precursor.

[0085] According to some exemplary embodiments, the first region 111, the second region 112, and the third region 113 can be arranged sequentially from the top of the reactor body 110. In this case, reducing gas can be injected from the bottom to the top of the reactor body 110. This allows the diameter of each region to decrease from the top to the bottom of the reactor body 110.

[0086] For example, by decreasing the diameter of the reactor body 110 from top to bottom, the flow rate of the reducing gas injected into the lower part of the reactor body 110 can be reduced from bottom to top. As a result, the first active material powder 50 with small particle size can be fluidized in the first region 111 with a large diameter, and the third active material powder 70 with large particle size can be fluidized in the third region 113 with a small diameter.

[0087] This can effectively prevent the problem that during the process of fluidizing the positive electrode active material mixture, the active material powder with a small particle size scatters or the active material powder with a large particle size is not fluidized, resulting in a decrease in the recovery efficiency of the lithium precursor.

[0088] For example, the gas inlet 105 is located at the lower part of the reactor body 110 and can inject a reducing gas. The reducing gas can include, for example, hydrogen gas. For example, the reducing gas is injected into the lower part of the reactor body 110 and can fluidize and reduce the positive electrode active material mixture contained inside the reactor body 110.

[0089] For example, the minimum fluidization velocity described later can mean the minimum flow velocity of the reducing gas for fluidizing the positive electrode active material powders 50, 60, 70. For example, the minimum fluidization velocity can be calculated using the following formula 1.

[0090]

Equation

[0091] In the formula 1, u mf is the minimum fluidization velocity, ε mf is the volume fraction of the active material powder particles, d p is the size of the active material powder particles, ρ g is the gas density of the reducing gas, ρ s is the solid density of the active material powder particles, μ is the gas viscosity of the reducing gas, φ s is the sphericity of the active material powder particles, and g may be the acceleration due to gravity.

[0092] For example, the flow velocity of the reducing gas in the fluidized bed reactor 100 can vary depending on the diameter of the reactor body 110 included in the fluidized bed reactor 100. For example, the flow velocity of the reducing gas can decrease as the diameter of the reactor body 110 increases.

[0093] In some exemplary embodiments, the minimum flow velocity within the first region 111 of the reducing gas may be less than or equal to the terminal velocity of the first active material powder 50. For example, terminal velocity may refer to the velocity at which an object is moving at a constant velocity when descending or moving in a fluid.

[0094] For example, terminal velocity can be calculated using equation 2 below.

[0095]

number

[0096] In the above equation 2, u t d is terminal velocity, p φ is the size of the active material powder particles. s This may also be a spherical diagram of the active material powder particles.

[0097] When the minimum flow velocity of the reducing gas within the first region 111 decreases to or below the terminal velocity of the first active material powder 50, the problem of the relatively small particle size of the first active material powder 50 scattering can be effectively prevented. Furthermore, since the first active material powder 50 can no longer rise to the top of the fluidized bed reactor 100 and descends, the amount of fluidized first active material powder 50 can be further increased. This can further improve the recovery efficiency of the lithium precursor.

[0098] In some exemplary embodiments, the maximum flow velocity in the second region 112 of the reducing gas may be greater than or equal to the minimum fluidization rate of the second active material powder 60, and the maximum flow velocity in the third region 113 of the reducing gas may be greater than or equal to the minimum fluidization rate of the third active material powder 70.

[0099] In this case, the second active material powder 60 and the third active material powder 70, which have larger particle sizes, can be fluidized more effectively. This effectively prevents the problem of the positive electrode active material powder not being fluidized and depositing at the bottom of the fluidized bed reactor 100.

[0100] In some exemplary embodiments, the reducing gas can be injected into the fluidized bed reactor 100 at a flow rate of 8 to 18 cm / s or more.

[0101] For example, by satisfying the aforementioned flow velocity range, the wide-diameter first region located at the top of the fluidized bed reactor prevents the first active material powder, which has small particle sizes, from scattering, while effectively fluidizing the third active material powder, which has large particle sizes. This improves the recovery efficiency of the lithium precursor.

[0102] According to some exemplary embodiments, the fluidized bed reactor 100 for reducing positive electrode active material of the present invention may include a first connecting portion 121 that connects a first region 111 and a second region 112, with its diameter decreasing from the first region 111 to the second region 112, and a second connecting portion 122 that connects the second region 112 and a third region 113, with its diameter decreasing from the second region 112 to the third region 113.

[0103] In this case, the first connecting portion 121 and the second connecting portion 122 prevent a sudden change in the diameter of the reactor body 110, thereby preventing a sudden decrease in the flow velocity of the reducing gas within the reactor body 110. This effectively prevents the problem of active material powder depositing on the sides of the reactor body 110 due to the decrease in the flow velocity of the reducing gas.

[0104] Referring to Figure 3, the fluidized bed reactor for reducing positive electrode active material of the present invention may further include a gas injection port 130 located on the side surface of the connecting portion 120. For example, a reducing gas or the like can be injected through the gas injection port 130. In this case, the gas injected from the gas injection port 130 can effectively prevent the deposition of active material powder on the side surface of the connecting portion 120.

[0105] According to some exemplary embodiments, the gas inlet 130 can be positioned so as to be inclined toward the side surface toward the upward direction of the reactor body 110. In this case, the gas inlet 130 positioned toward the upward direction of the reactor body 110 can more effectively prevent the problem of the positive electrode active material powders 50, 60, and 70 depositing on the side surface of the connecting portion 120.

[0106] According to some exemplary embodiments, the angle α formed by the side surface of the connecting portion 120 and the gas injection port 130 may be 45 to 90°. When the angle α formed by the side surface of the connecting portion 120 and the gas injection port 130 falls within this range, the problem of the active material powder depositing on the side surface of the connecting portion 120 can be prevented more effectively.

Claims

1. A step of preparing multiple positive electrode active material powders containing lithium composite oxide particles and having different particle sizes from each other, The steps include: reducing the positive electrode active material powder in a fluidized bed reactor, which includes a reactor body in which the diameter decreases stepwise or gradually from top to bottom, to produce a preliminary precursor mixture; A method for regenerating a lithium precursor, comprising the step of recovering a lithium precursor from the aforementioned preliminary precursor mixture, The positive electrode active material powder comprises a first active material powder, a second active material powder, and a third active material powder, each having different particle sizes. A method for regenerating a lithium precursor, wherein the reactor body includes a first region where the first active material powder is fluidized, a second region where the second active material powder is fluidized, and a third region where the third active material powder is fluidized.

2. The method for regenerating a lithium precursor according to claim 1, wherein the first region, the second region, and the third region are arranged sequentially from the upper part of the reactor body.

3. The method for regenerating a lithium precursor according to claim 2, wherein the diameter of the first region is greater than the diameter of the second region, and the diameter of the second region is greater than the diameter of the third region.

4. The method for regenerating a lithium precursor according to claim 3, wherein the ratio of the diameter of the first region to the diameter of the third region is 4 to 16.

5. The method for regenerating a lithium precursor according to claim 3, wherein the ratio of the diameter of the second region to the diameter of the third region is 2 to 4.

6. The method for regenerating a lithium precursor according to claim 2, wherein the particle size of the first active material powder is smaller than that of the second active material powder, and the particle size of the second active material powder is smaller than that of the third active material powder.

7. The method for regenerating a lithium precursor according to claim 6, wherein the particle size of the first active material powder is less than 10 μm, the particle size of the second active material powder is 10 to 100 μm, and the particle size of the third active material powder is 100 μm or more.

8. The method for regenerating a lithium precursor according to claim 1, wherein the step of producing the preliminary precursor mixture further comprises injecting a reducing gas into the fluidized bed reactor.

9. The method for regenerating a lithium precursor according to claim 8, wherein the minimum flow velocity of the reducing gas within the first region is less than or equal to the terminal velocity of the first active material powder.

10. The method for regenerating a lithium precursor according to claim 8, wherein the maximum flow velocity of the reducing gas in the second region is greater than or equal to the minimum fluidization rate of the second active material powder, and the maximum flow velocity of the reducing gas in the third region is greater than or equal to the minimum fluidization rate of the third active material powder.

11. The method for regenerating a lithium precursor according to claim 8, wherein the reducing gas is injected into the fluidized bed reactor at a flow rate of 8 to 18 cm / s.

12. A method for regenerating a lithium precursor according to claim 1, comprising: a first connecting portion that connects the first region and the second region, wherein the diameter decreases as you move from the first region to the second region; and a second connecting portion that connects the second region and the third region, wherein the diameter decreases as you move from the second region to the third region.

13. The method for regenerating a lithium precursor according to claim 12, wherein the first connecting portion and the second connecting portion further include a gas injection port located on the side.

14. The method for regenerating a lithium precursor according to claim 13, wherein the gas injection port is arranged to be inclined toward the side surface toward the upward of the reactor body.

15. The method for regenerating a lithium precursor according to claim 13, wherein the angle formed between the side surfaces of the first and second connecting portions and the gas injection port is 45 to 90°.

16. A reactor body in which the diameter decreases in stages or gradually from top to bottom, The reactor body includes an active material inlet into which multiple positive electrode active material powders containing lithium composite oxide particles and having different particle sizes are injected, A fluidized bed reactor for reducing positive electrode active material, comprising a gas inlet located at the bottom of the reactor body into which a reducing gas is injected to fluidize the active material powder, The positive electrode active material powder comprises a first active material powder, a second active material powder, and a third active material powder, each having different particle sizes. The reactor body includes a first region in which the first active material powder is fluidized, a second region in which the second active material powder is fluidized, and a third region in which the third active material powder is fluidized. A first connecting portion connects the first region and the second region, and the diameter decreases as you move from the first region to the second region, A fluidized bed reactor for reducing a positive electrode active material, comprising a second connecting portion that connects the second region and the third region, the second connecting portion having a diameter that decreases as it moves from the second region to the third region.

17. The fluidized bed reactor for reducing positive electrode active material according to claim 16, wherein the first and second connecting portions further include gas injection ports located on the sides.

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