Method for manufacturing pre-treatment materials for recovering valuable metals from lithium secondary batteries

Abstract

The method for producing a pretreated material for recovering valuable metals from a lithium secondary battery includes the steps of preparing a positive electrode active material mixture from a positive electrode of a lithium secondary battery, drying or pulverizing the positive electrode active material mixture, and classifying the dried or pulverized positive electrode active material mixture so that the average particle size (D50) is 400 μm or less. The average particle size can be reduced before the reduction process to increase the fluidity.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a pretreatment product for recovering valuable metals from a lithium secondary battery, and also relates to a method for recovering valuable metals from a lithium secondary battery.

Background Art

[0002] A secondary battery is a battery that can be repeatedly charged and discharged, and has been widely applied to portable electronic communication devices such as camcorders, mobile phones, and notebook computers as the information communication and display industries have developed. Examples of secondary batteries include lithium secondary batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and the like. Among them, lithium secondary batteries have been actively developed and applied because of 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 can include an electrode assembly including a positive electrode, a negative electrode, and a separator, and an electrolyte that impregnates the electrode assembly. The lithium secondary battery can further include, for example, a pouch-shaped exterior material that houses the electrode assembly and the electrolyte.

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

[0005] The lithium metal oxide as the positive electrode active material can be manufactured by reacting a lithium precursor with a transition metal precursor containing nickel, cobalt, and manganese.

[0006] The use of the aforementioned high-cost valuable metals in the positive electrode active material results in significant costs for manufacturing the positive electrode material. Furthermore, in recent years, with growing concern for environmental protection, research into methods for recycling positive electrode active materials is progressing. For the recycling of the positive electrode active material, it is necessary to regenerate the lithium precursor and transition metal precursor from the positive electrode with high efficiency and high purity. [Overview of the project] [Problems that the invention aims to solve]

[0007] One objective of the present invention is to provide a method for producing a pre-treated material for recovering valuable metals from lithium secondary batteries that is highly efficient and reliable.

[0008] One objective of the present invention is to provide a method for recovering valuable metals from lithium secondary batteries that is highly efficient and reliable. [Means for solving the problem]

[0009] A method for producing a pre-treated material for recovering valuable metals from lithium secondary batteries according to an embodiment of the present invention includes the steps of: preparing a positive electrode active material mixture from the positive electrode of a lithium secondary battery; drying or pulverizing the positive electrode active material mixture; and classifying the dried or pulverized positive electrode active material mixture so that the average particle size (D50) is 400 μm or less.

[0010] In some embodiments, the positive electrode includes a positive electrode current collector and a positive electrode active material layer formed on the positive electrode current collector, and the step of preparing the positive electrode active material mixture may include removing the positive electrode current collector from the positive electrode.

[0011] In some embodiments, the drying can be carried out at 60-100°C for 48-96 hours.

[0012] In some embodiments, the grinding can be carried out by an impact crusher, which may include a ball mill or a hammer mill.

[0013] In some embodiments, the classification can be performed by vibrating and screening the dried or pulverized cathode active material mixture.

[0014] In some embodiments, the steps of drying the positive electrode active material mixture, grinding the dried positive electrode active material mixture, and classifying the ground positive electrode active material mixture so that the average particle size is 400 μm or less can be carried out sequentially.

[0015] In some embodiments, the prepared cathode active material mixture may contain both large aggregated particles with a particle size of 1 to 100 mm and fine powder with a particle size of less than 1 mm.

[0016] In some embodiments, the classified cathode active material mixture may not contain the large aggregated particles.

[0017] A method for recovering valuable metals from a lithium secondary battery according to an embodiment of the present invention includes the steps of reducing the classified positive electrode active material mixture to form a preprecursor mixture, and recovering a lithium precursor and a transition metal precursor from the preprecursor mixture.

[0018] In some embodiments, the step of forming the preprecursor mixture may include the steps of fluidizing the classified cathode active material mixture with a fluidizing gas in a fluidized bed reactor, and injecting a reducing gas into the fluidized bed reactor to form a preprecursor mixture from the fluidized cathode active material mixture.

[0019] In some embodiments, the reducing gas may include hydrogen.

[0020] In some embodiments, the pre-precursor mixture may include pre-lithium precursor particles and pre-transition metal precursor particles.

[0021] In some embodiments, the step of recovering the lithium precursor and the transition metal precursor from the preliminary precursor mixture may include the step of washing the preliminary lithium precursor particles with water to collect the lithium precursor, and the step of treating the preliminary transition metal precursor with an acid to collect the transition metal precursor.

[0022] In some embodiments, the step of forming the preliminary precursor mixture may include the step of treating the classified positive electrode active material mixture with an acidic solution containing a reducing agent.

[0023] In some embodiments, the step of recovering the lithium precursor and the transition metal precursor from the preliminary precursor mixture may include the step of adding an extractant to a solution containing the positive electrode active material mixture treated with the acidic solution to collect the lithium precursor and the transition metal precursor.

Advantages of the Invention

[0024] The method for manufacturing a pretreatment product for recovering valuable metals of a lithium secondary battery according to an embodiment of the present invention may include the step of drying or pulverizing a positive electrode active material mixture, and the step of classifying the dried or pulverized positive electrode active material mixture so that the average particle size is 400 μm or less. Thereby, the average particle size of the positive electrode active material mixture is uniformly reduced, and the reactivity in the subsequent reduction process can be improved.

[0025] In some embodiments, the drying can be performed at 60 to 100 °C for 48 to 96 hours. When drying is performed under the above conditions, the electrolytic solution and moisture in the mixture are sufficiently removed, the subsequent classification step can be smoothly performed, and aggregation of particles due to drying at an excessive high temperature can be prevented.

[0026] In some embodiments, the positive electrode active material mixture can be sequentially dried, pulverized, and classified. In this case, by sequentially performing the drying and pulverization steps, the large agglomerated particles can be sufficiently pulverized, so that the particle size of the classified mixture can be formed relatively uniformly. As a result, the reduction reaction of the positive electrode active material mixture can be sufficiently performed as a whole. Further, in the case of a fluidity reduction reaction, the fluidity of the positive electrode active material mixture can be improved.

Brief Description of the Drawings

[0027] [Figure 1] FIG. 1 is a schematic flowchart for explaining a method of manufacturing a pretreatment product for recovering an active metal of a lithium secondary battery according to an exemplary embodiment. [Figure 2] FIG. 2 is a schematic flowchart for explaining a method of recovering an active metal of a lithium secondary battery according to an exemplary embodiment. [Figure 3] FIG. 3 is a schematic graph showing the particle size distributions of Examples and Comparative Examples.

Embodiments for Carrying Out the Invention

[0028] Embodiments of the present invention provide a method of manufacturing a pretreatment product for recovering valuable metals of a lithium secondary battery, including a pretreatment step of reducing the average particle size of a positive electrode active material mixture. Further, embodiments of the present invention provide a method of recovering valuable metals of a lithium secondary battery using the pretreatment product manufactured by the above method.

[0029] Hereinafter, embodiments of the present invention will be described in detail. However, the present invention can be variously modified and can have various forms, and specific embodiments are illustrated in the drawings and will be described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, and it should be understood to include all modifications, equivalents, or alternatives included in the spirit and technical scope of the present invention.

[0030] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as those generally understood by a person of ordinary skill in the art to which this invention pertains. Terms as defined in commonly used dictionaries should be interpreted as having the meaning consistent with their meaning in the context of the relevant art, and not as ideal or overly formal unless explicitly defined herein.

[0031] 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.

[0032] <Method for manufacturing pre-treated materials for recovering valuable metals from lithium secondary batteries> Figure 1 is a schematic flowchart illustrating a method for manufacturing a pretreatment material for active metal recovery from lithium secondary batteries according to an exemplary embodiment.

[0033] Referring to Figure 1, the positive electrode active material can be prepared from the positive electrode of a lithium secondary battery (for example, step S10).

[0034] The 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.

[0035] For example, the positive electrode active material contained in the positive electrode active material layer may include an oxide containing lithium and a transition metal.

[0036] In some embodiments, the positive electrode active material may include a compound having a composition represented by the following chemical formula 1.

[0037] [Chemical formula 1] Li x Ni 1-y M y O 2+z

[0038] In chemical formula 1, x is 0.9 ≤ x ≤ 1.2, y is 0 ≤ y ≤ 0.7, z is -0.1 ≤ z ≤ 0.1, and M may be one or more elements selected from Na, Mg, Ca, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Co, Fe, Cu, Ag, Zn, B, Al, Ga, C, Si, Sn, or Zr.

[0039] In some embodiments, the positive electrode active material may be an NCM-based lithium oxide containing nickel, cobalt, and manganese.

[0040] The positive electrode can be separated from the lithium secondary battery and recovered. The positive electrode may be from a used lithium secondary battery or a positive electrode that was damaged or defective during the manufacturing process.

[0041] For example, 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.

[0042] The conductive material may include, for example, carbon-based materials such as graphite, carbon black, graphene, and carbon nanotubes. The binder may include, for example, resin materials such as vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidene fluoride (PVDF), polyacrylonitrile, and polymethyl methacrylate.

[0043] In exemplary embodiments, the positive electrode current collector can be removed from the recovered positive electrode to collect the positive electrode active material mixture. This allows the positive electrode active material mixture to be collected in the form of a powder from which aluminum has been removed. The positive electrode active material mixture may include, as described above, a lithium transition metal oxide powder, for example, an NCM-based lithium oxide powder (e.g., Li(NCM)O2).

[0044] In exemplary embodiments, the positive electrode active material mixture may include positive electrode active material mixture particles, such as the NCM-based lithium oxide. For example, the positive electrode active material mixture may be substantially composed of the positive electrode active material mixture particles.

[0045] For example, the collected cathode active material mixture may contain a mixture of large aggregated particles having a particle size of 1 to 100 mm and fine powder having a particle size of less than 1 mm. If the prepared cathode active material mixture is introduced into the reduction step described later without further pretreatment, a non-uniform particle size distribution may cause a non-uniform reaction in the reduction step.

[0046] For example, if the reduction process is a fluidization process as described later, large aggregated particles may not be fluidized, and the reduction reaction may not proceed sufficiently. As a result, process efficiency may decrease, and the recovery rate of valuable metals may decline.

[0047] Furthermore, if the reduction process is a wet leaching process as described later, the specific surface area of ​​the positive electrode active material mixture particles may increase, and the reactivity to the reducing agent may decrease.

[0048] According to exemplary embodiments of the present invention, the prepared positive electrode active material mixture can be dried or pulverized (e.g., step S20).

[0049] In some embodiments, the prepared positive electrode active material mixture can be dried. In this case, the electrolyte and water contained in the prepared positive electrode active material mixture can be removed. This increases the fluidity of the mixture and improves the purity of the valuable metals contained in the mixture.

[0050] For example, the drying can be carried out at 60-100°C for 48-96 hours. When drying is performed under these conditions, the electrolyte and moisture in the mixture are sufficiently removed, allowing the classification process described later to proceed smoothly and preventing excessive particle aggregation due to drying at excessively high temperatures. This makes it possible to form a uniform particle size distribution in the positive electrode active material mixture after classification.

[0051] In some embodiments, the prepared positive electrode active material mixture can be pulverized. For example, this pulverization can be carried out by an impact crusher, including a ball mill or a hammer mill.

[0052] For example, the impact crusher can be defined as "a machine that crushes an object using the impact force from the impact of a ball or a hammer."

[0053] For example, by performing the aforementioned grinding step, large aggregated particles contained in the prepared positive electrode active material mixture can be ground into a fine powder. This reduces the average particle size of the positive electrode active material mixture, enabling a uniform reduction reaction and excellent fluidity.

[0054] In an exemplary embodiment, the dried or pulverized positive electrode active material mixture can be classified so that the average particle size (D50) is 400 μm or less to produce a pre-treated material for recovering valuable metals from lithium secondary batteries (e.g., step S30).

[0055] In this invention, "average particle size" or "D50" may mean the particle size at which the cumulative volume percentage in the particle size distribution determined from the particle volume corresponds to 50%.

[0056] In this invention, "pre-treated material" may mean a classified mixture of positive electrode active materials after pulverization or drying.

[0057] For example, the classification can be performed by vibrating and screening a dried or pulverized cathode active material mixture. For example, the mixture can be classified by vibrating it on a screen with a mesh size of 400 μm. For example, the classification can be performed using a twist screen apparatus.

[0058] For example, by performing the classification process described above, the particle size of the dried or pulverized positive electrode active material mixture particles can be uniformly controlled. In this case, a uniform reaction can be carried out in the reduction process described later, and in the case of a fluidized reduction process, the fluidity of the mixture can be increased. As a result, process efficiency is improved, and valuable metals can be recovered with high efficiency and high purity.

[0059] In some embodiments, the steps of drying the prepared positive electrode active material mixture, grinding the dried positive electrode active material mixture, and classifying the ground positive electrode active material mixture so that the average particle size is 400 μm or less can be carried out sequentially.

[0060] For example, the prepared positive electrode active material mixture can first be introduced into the drying process described above. This removes the electrolyte and moisture from the mixture, allowing the grinding process to proceed smoothly. This allows the average particle size of the positive electrode active material mixture after classification to be sufficiently reduced (e.g., 400 μm or less).

[0061] For example, the dried positive electrode active material mixture can be pulverized. Since the electrolyte and moisture have been removed, the pulverization performance against large aggregated particles contained in the mixture can be improved.

[0062] For example, the pulverized positive electrode active material mixture can be classified to have an average particle size of 400 μm or less to obtain a pre-treated material for recovering valuable metals from lithium secondary batteries. In this case, by sequentially performing the drying and pulverizing steps, large aggregated particles can be sufficiently pulverized, so that the particle size of the classified mixture can be made relatively uniform. As a result, the reduction reaction of the positive electrode active material mixture can be carried out sufficiently overall, and in the case of a fluid reduction reaction, the fluidization of the positive electrode active material mixture can be facilitated.

[0063] For example, if the average particle size of the positive electrode active material mixture exceeds 400 μm, the specific surface area of ​​the positive electrode active material mixture decreases, which can reduce the reactivity of the reduction reaction and the fluidity of the particles. As a result, the recovery rate of valuable metals contained in the positive electrode active material mixture may decrease.

[0064] In some embodiments, the positive electrode active material can undergo additional heat treatment before being introduced into the reduction leaching process described later. For example, this additional heat treatment can at least partially remove impurities such as conductive materials and binders contained in the positive electrode active material layer. This allows the positive electrode active material mixture containing high-purity valuable metals to be introduced into the reduction process.

[0065] The temperature of the heat treatment may be, for example, about 100 to 500°C, preferably about 350 to 450°C. Within this range, the impurities can be substantially removed, and the destruction or damage of the positive electrode active material mixture can be prevented.

[0066] <Methods for recovering valuable metals from lithium-ion batteries> Figure 2 is a schematic flowchart illustrating a method for recovering active metals from a lithium secondary battery according to an exemplary embodiment.

[0067] Referring to Figure 2, the pre-treated material obtained as described above (e.g., the classified cathode active material mixture) can be reduced to form a preliminary precursor mixture (e.g., step S40).

[0068] The pre-precursor mixture may include pre-lithium precursor particles and pre-transition metal precursor particles.

[0069] The preliminary lithium precursor particles may include, for example, at least one of lithium hydroxide (LiOH), lithium oxide (Li2O), and lithium carbon oxide (Li2CO3). From the viewpoint of charge / discharge characteristics, life characteristics, and high-temperature stability of lithium secondary batteries, the lithium precursor may include lithium hydroxide.

[0070] Pre-transition metal precursor particles can include, for example, Ni, Co, NiO, CoO, and MnO.

[0071] In some embodiments, the reduction can be carried out by a fluidized reduction step in which the classified positive electrode active material mixture is fluidized and then subjected to reduction treatment. For example, the reduction can be carried out by a fluidized bed reactor.

[0072] As used herein, the term "fluidized bed reactor" may mean a reactor through which a fluid (gas or liquid) is passed over an injected pre-positive electrode active material mixture to fluidize the positive electrode active material mixture.

[0073] For example, the pre-treated material can be introduced into a fluidized bed reactor, and a fluidizing gas can be injected into the fluidized bed reactor to fluidize the positive electrode active material mixture.

[0074] For example, the fluidizing gas may be an oxygen or nitrogen-containing gas.

[0075] The aforementioned pretreatment material includes a fine powder with an average particle size of 400 μm or less after removing large aggregated particles, and may also contain particles with a uniform particle size overall after classification. In this case, the mixture can be smoothly fluidized with a fluidizing gas. This allows the reduction reaction of the pretreatment material to be carried out uniformly overall, increasing the yield of the prepreparative mixture and improving the recovery rate of valuable metals.

[0076] In some embodiments, the fluidized pretreatment material can be reduced by a reducing gas injected into a fluidized bed reactor to form a prepreglue mixture.

[0077] For example, the reducing gas may be a mixture of hydrogen and a non-reactive gas.

[0078] In some embodiments, the reduction can be carried out by a wet leaching process in which the classified cathode active material mixture is placed in an acidic solution together with a reducing agent and reduced.

[0079] The reducing agent may include, for example, at least one of hydrogen peroxide (H2O2), SO2, Na2S, NaHS, Na2S2O5, NaHSO3, Na2S2O3, KHSO3, K2SO3, FeSO4, H2S, glucose, sucrose, and ascorbic acid.

[0080] The acidic solution may include, for example, at least one of sulfuric acid (H2SO4), hydrochloric acid (HCl), nitric acid (HNO3), oxalic acid, and citric acid.

[0081] For example, a classified positive electrode active material mixture can be added to the acidic solution together with a reducing agent to form a preliminary precursor mixture. Since the average particle size of the positive electrode active material mixture is controlled to 400 μm or less and large aggregated particles are removed, the specific surface area of ​​the positive electrode active material mixture particles can be increased, for example, and the reactivity to the reducing agent can be increased.

[0082] In exemplary embodiments, lithium precursors and transition metal precursors can be recovered from the formed preliminary precursor mixture (e.g., step S50).

[0083] The aforementioned pre-precursor mixture may include pre-lithium precursor particles and pre-transition metal precursor particles.

[0084] In some embodiments in which a preprecursor mixture is formed by the aforementioned fluidization reduction process, the preprecursor mixture can be reacted with the leachate to form a lithium precursor. For example, prelithium precursor particles contained in the preprecursor mixture can react with the leachate to form a lithium precursor.

[0085] For example, lithium oxide and lithium carbon oxide react with leachate to form lithium hydroxide, and the formed lithium hydroxide can be dissolved in the leachate and collected.

[0086] In some embodiments, the leachate may contain water. In this case, the preliminary precursor mixture can be washed with water. This washing process causes the preliminary precursor mixture to react with water to form a lithium precursor in which lithium hydroxide is dissolved in water.

[0087] In some exemplary embodiments, the leachate may further contain dimethyl carbonate or diethyl carbonate.

[0088] For example, dimethyl carbonate or diethyl carbonate can accelerate the reaction between the preliminary precursor mixture and water. This can improve the separation efficiency of the lithium precursor.

[0089] In some embodiments, preliminary transition metal precursor particles in a preliminary precursor mixture can react with an acidic solution to form a transition metal precursor. For example, the precipitated transition metal precursor can be collected.

[0090] For example, sulfuric acid can be used as the acid solution. In this case, the transition metal precursor may include a transition metal sulfate. For example, the transition metal sulfate may include NiSO4, MnSO4, and CoSO4.

[0091] In some embodiments in which a preliminary precursor mixture is formed by the aforementioned wet leaching process, an extractant can be added to the solution containing the preliminary precursor mixture to extract lithium precursors and transition metal precursors.

[0092] The extractant may include, for example, at least one of a phosphate-based extractant, a phosphate-based extractant, a phosphine oxide-based extractant, and a carboxylic acid-based extractant.

[0093] For example, the extractant may include at least one of the following: di-2-ethylhexyl phosphoric acid (D2EHPA), bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex 272), 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester (PC88A), tributyl phosphate, trioctyl phosphine oxide, and alkyl monocarboxylic acid.

[0094] The following are specific examples to aid in understanding the present invention, but these examples are merely illustrative and do not limit the scope of the appended claims. It will be obvious to those skilled in the art that various changes and modifications can be made to these examples within the scope of the present invention and the technical concept, and it is also obvious that these variations and modifications fall within the scope of the appended claims.

[0095] Example 1 One kilogram of positive electrode material separated from a waste lithium secondary battery was cut into small units and pulverized by milling to prepare a positive electrode active material mixture containing Li-Ni-Co-Mn oxide, a binder (polyvinylidene fluoride, PVDF), and a conductive material (carbon black) (Step S10).

[0096] The positive electrode active material mixture was placed in an oven and dried at 80°C for 72 hours. Then, the dried positive electrode active material mixture was placed in an impact crusher and pulverized (step S20).

[0097] The pulverized cathode active material mixture was placed on a twist screen with a mesh size of 400 μm and classified (Step S30).

[0098] The classified positive electrode active material mixture was placed in a fluidized bed reactor and fluidized by introducing nitrogen gas. Hydrogen gas was introduced into the fluidized bed reactor as a reducing gas to reduce the fluidized positive electrode active material mixture and form a preliminary precursor mixture (Step S40).

[0099] The formed preliminary precursor mixture was washed with water to obtain an aqueous lithium precursor solution. The preliminary precursor mixture was also treated with acid to obtain a transition metal precursor (step S50).

[0100] Example 2 Valuable metals were recovered in the same manner as in Example 1, except that the drying temperature was set to 55°C.

[0101] Example 3 Valuable metals were recovered in the same manner as in Example 1, except that classification was performed immediately after drying without grinding.

[0102] Example 4 Valuable metals were recovered in the same manner as in Example 1, except that the cathode active material mixture, which was prepared without drying, was pulverized and immediately classified.

[0103] Comparative Example 1 Valuable metals were recovered in the same manner as in Example 1, except that the prepared cathode active material mixture was immediately introduced into a fluidized bed reactor without drying, grinding, or classifying.

[0104] Comparative Example 2 Valuable metals were recovered in the same manner as in Example 1, except that the crushed cathode active material mixture was placed on a twist screen with a mesh size of 500 μm and classified.

[0105] Experimental example (1) Measurement of average particle size (D50, D90) The average particle size of the classified positive electrode active material mixtures from the aforementioned examples and Comparative Example 2, as well as the prepared positive electrode active material mixture from Comparative Example 1, was measured using a laser diffraction scattering instrument, Mastersizer 3000 (Malvern).

[0106] (2) Assessment of liquidity After the positive electrode active material mixture introduced into the fluidized bed reactor according to the above-described examples and comparative examples was fluidized, the fluidity was evaluated by visual observation as follows. ○: No large aggregated particles that do not flow were observed. X: Large aggregated particles that do not flow are observed.

[0107] (3) Measurement of the recovery rate of valuable metals In the aforementioned examples and comparative examples, the weight of recovered lithium and transition metals relative to the weight of lithium and transition metals in the initial cathode active material mixture sample was measured, and the valuable metal recovery rate was calculated. The measurement and evaluation results are shown in Table 1 below.

[0108] [Table 1]

[0109] Referring to Table 1, the examples in which the cathode active material mixture was dried or pulverized and classified to an average particle size of 400 μm or less before being fed into the reduction process showed an overall lower average particle size, increased fluidity, and increased valuable metal recovery rate compared to the comparative example.

[0110] Furthermore, Comparative Examples 1 and 2 had low fluidity and could not undergo the fluidization reaction, making it impossible to recover valuable metals.

[0111] Figure 3 is a schematic graph showing the particle size distribution of Example 1 and Comparative Example 1.

[0112] Referring to Figure 3, in Example 1, the mixture was mostly formed in the form of fine powder with a particle size of 400 μm or less, while in Comparative Example 1, large aggregated particles with a particle size of 1,000 μm or more were included.

[0113] In Example 2, where the mixture was dried at a temperature below 60°C, the electrolyte and moisture in the positive electrode active material mixture could not evaporate sufficiently, resulting in reduced efficiency in the subsequent grinding and classification processes. Consequently, the average particle size and the recovery rate of valuable metals were slightly lower compared to Example 1.

[0114] In Example 3, where classification was performed immediately after drying without a grinding process, and in Example 4, where the cathode active material mixture was immediately ground and classified without drying, the average particle size increased relatively compared to Examples 1 and 2, where drying, grinding, and classification were all performed, and the recovery rate of valuable metals decreased.

Claims

1. The steps include preparing a positive electrode active material mixture from the positive electrode of a lithium secondary battery, The steps include drying the positive electrode active material mixture, The steps include: grinding the dried positive electrode active material mixture, The step includes classifying the dried and pulverized positive electrode active material mixture so that the average particle size (D50) is 400 μm or less. A method for producing a pre-treated material for recovering valuable metals from lithium secondary batteries, wherein the drying step, the crushing step, and the classification step are carried out in sequence.

2. The positive electrode includes a positive electrode current collector and a positive electrode active material layer formed on the positive electrode current collector. The method for producing a pre-treated material for recovering valuable metals from a lithium secondary battery according to claim 1, wherein the step of preparing the positive electrode active material mixture includes removing the positive electrode current collector from the positive electrode.

3. The method for producing a pre-treated product for recovering valuable metals from lithium secondary batteries according to claim 1, wherein the drying is carried out at 60 to 100°C for 48 to 96 hours.

4. The method for producing a pre-treated material for recovering valuable metals from lithium secondary batteries according to claim 1, wherein the crushing is performed by an impact crusher including a ball mill or a hammer mill.

5. The method for producing a pre-treated material for recovering valuable metals from a lithium secondary battery according to claim 1, wherein the classification is performed by vibrating and screening the dried or pulverized positive electrode active material mixture.

6. The method for producing a pre-treated material for recovering valuable metals from a lithium secondary battery, according to claim 1, wherein the prepared positive electrode active material mixture includes both large aggregated particles with a particle size of 1 to 100 mm and fine powder with a particle size of less than 1 mm.

7. The method for producing a pre-treated material for recovering valuable metals from a lithium secondary battery according to claim 6, wherein the classified positive electrode active material mixture does not contain the large aggregated particles.

8. The steps of reducing the classified positive electrode active material mixture according to claim 1 to form a preliminary precursor mixture, A method for recovering valuable metals from a lithium secondary battery, comprising the step of recovering a lithium precursor and a transition metal precursor from the aforementioned preliminary precursor mixture.

9. The step of forming the aforementioned preliminary precursor mixture is: The steps include: fluidizing the classified positive electrode active material mixture in a fluidized bed reactor with a fluidizing gas; A method for recovering valuable metals from a lithium secondary battery according to claim 8, comprising the steps of injecting a reducing gas into the fluidized bed reactor to form a preliminary precursor mixture from the fluidized positive electrode active material mixture.

10. The method for recovering valuable metals from a lithium secondary battery according to claim 9, wherein the reducing gas includes hydrogen.

11. The method for recovering valuable metals from a lithium secondary battery according to claim 9, wherein the pre-precursor mixture comprises pre-lithium precursor particles and pre-transition metal precursor particles.

12. The step of recovering lithium precursors and transition metal precursors from the aforementioned preliminary precursor mixture is: The steps include: washing the aforementioned preliminary lithium precursor particles with water to collect the lithium precursor; A method for recovering valuable metals from a lithium secondary battery according to claim 11, comprising the step of treating the aforementioned transition metal precursor with acid to collect the transition metal precursor.

13. The step of forming the aforementioned preliminary precursor mixture is: A method for recovering valuable metals from a lithium secondary battery according to claim 8, comprising the step of treating the classified positive electrode active material mixture with an acidic solution containing a reducing agent.

14. The step of recovering lithium precursors and transition metal precursors from the aforementioned preliminary precursor mixture is: A method for recovering valuable metals from a lithium secondary battery according to claim 13, comprising the step of adding an extractant to a solution containing a positive electrode active material mixture treated with the acidic solution, and collecting the lithium precursor and the transition metal precursor.

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