Method for concentrating valuable metals contained in a lithium ion secondary battery

Abstract

Provided is a method for concentrating valuable metals contained in a lithium-ion secondary battery, the concentration method treating a lithium-ion secondary battery or a positive electrode material thereof containing at least one element of cobalt and nickel to concentrate valuable metals including at least one of cobalt and nickel, and including the following steps: a heat treatment step of heat treating the lithium-ion secondary battery or the positive electrode material thereof to form an agglomerate containing at least one valuable metal of cobalt and nickel.

Description

Technical Field

[0001] The present invention relates to a method for concentrating valuable metals contained in a lithium ion secondary battery. Background Art

[0002] Compared with conventional lead-acid batteries, nickel-cadmium secondary batteries, etc., lithium ion secondary batteries are lightweight, high-capacity, and high-electromotive-force secondary batteries, and are used as secondary batteries for personal computers, electric vehicles, portable devices, etc. For example, valuable metals such as cobalt and nickel are used in the form of lithium cobaltate (LiCoO 2 ), ternary cathode active material (LiNi x Co y Mn z O 2 (x + y + z = 1)) etc. in the cathode of a lithium ion secondary battery.

[0003] Since it is predicted that the use of lithium ion secondary batteries will also expand in the future, from the perspective of resource recovery, it is desirable to concentrate valuable metals such as cobalt and nickel from defective products generated during the manufacturing process and lithium ion secondary batteries discarded due to the use of equipment and battery life.

[0004] For example, as a technique for recovering valuable metals from waste lithium ion secondary batteries, the following method has been proposed: heating the waste secondary battery at 300 to 500 °C in an oxygen-containing gas stream, separating and removing the metal foil and recovering it, and heating the recovered material again at 500 to 650 °C in an oxygen-containing gas stream to remove combustible substances, thereby recovering it in the form of a metal compound for use as a cathode material (see Patent Document 1). In this method, the thermal decomposition treatment is carried out in two stages. In the first stage until the electrode material is peeled off from the metal foil, the decomposition of graphite in the electrode material is suppressed as much as possible. In addition, in the second stage after separating and removing the metal foil, graphite decomposition is carried out. Thus, the sintering phenomenon of increasing the particle size of the recovered metal compound is suppressed as much as possible.

[0005] In addition, for example, the following method has been proposed: heating a lithium ion battery wrapped in an aluminum case at a low temperature of 400 to 550 °C, heating the sieved battery powder after crushing and classification at a high temperature of 550 to 700 °C to effectively remove aluminum, and converting valuable metals such as cobalt into a form suitable for magnetic separation and flotation (see Patent Document 2).

[0006] However, the technique described in Patent Document 1 aims to directly reuse the recovered electrode material in the form of a metal compound for use as a cathode material, and thus does not focus on recovering nickel and cobalt in the form of metals at all.

[0007] In addition, the object of the technology described in Patent Document 2 is to separate cobalt from a mixture of aluminum, lithium aluminate, copper, copper oxide, carbon, etc. for a battery using a cobalt-based positive electrode material such as lithium cobaltate. Regarding how to separate manganese from ternary positive electrode materials (LiNi x Co y Mn z O 2 (x + y + z = 1)) and other oxides containing cobalt, nickel, and manganese by heat treatment and physical screening is not mentioned.

[0008] As a technology for concentrating cobalt and nickel from a lithium-ion secondary battery, for example, the following technology has been proposed: by roasting an electrode material in the presence of oxygen and leaching the sintered body in an inorganic acid to separate and concentrate cobalt, copper, and aluminum (for example, see Patent Document 3). In this prior art, cobalt and aluminum can be leached in an inorganic acid to separate copper. In addition, cobalt and aluminum can be separated by adjusting the pH of the inorganic acid.

[0009] In addition, for example, the following technology has been proposed: a two-stage solvent extraction process is performed on a metal mixed aqueous solution containing a metal group A composed of lithium, manganese, nickel, and cobalt and a metal group B composed of copper, aluminum, and iron to separate the metal group B and manganese from lithium, nickel, and cobalt (for example, see Patent Document 4).

[0010] In addition, for example, the following technology has been proposed: thermally decomposing, crushing, and classifying a waste lithium-ion secondary battery under superheated steam at 350°C to 550°C to concentrate the valuable metals contained in the positive electrode material (for example, see Patent Document 5). Thereby, while suppressing the generation of metal oxidation and dioxins, the organic matter contained in the lithium-ion secondary battery can be thermally decomposed at low cost. At the same time, the valuable metals contained in the positive electrode material can be concentrated without melting the aluminum (melting point 660°C) contained in the case and the positive electrode current collector.

[0011] However, in the technology described in Patent Document 3 mentioned above, there are problems such as the need for complicated processes such as filtering the inorganic acid and adjusting the pH.

[0012] In addition, in the technology described in Patent Document 4, there are problems such as the need for solvent extraction to separate manganese from cobalt, nickel, and lithium, resulting in excessive costs for the extractant and equipment introduction.

[0013] In addition, in the technology described in Patent Document 5, for example, although aluminum and copper can be separated at a high concentration rate, cobalt and nickel are not metallized, and metals such as lithium, cobalt, nickel, and manganese are only concentrated in the form of mixed compounds.

[0014] Prior art documents

[0015] Patent documents

[0016] Patent Document 1: Japanese Patent Laid-Open No. 2000-348782

[0017] Patent Document 2: Japanese Patent Laid-Open No. 2017-37807

[0018] Patent Document 3: Japanese Patent Laid-Open No. 2019-169309

[0019] Patent Document 4: Japanese Patent No. 5706457

[0020] Patent Document 5: Pamphlet of International Publication No. 2012 / 169073 Summary of the Invention

[0021] Problems to be Solved by the Invention

[0022] An object of the present invention is to provide a method for concentrating valuable metals contained in a lithium ion secondary battery, which targets a used lithium ion secondary battery, a positive electrode material of a used lithium ion secondary battery, or waste materials from their manufacturing processes, etc., and can easily obtain a metal component with concentrated cobalt and nickel, and is easy to separate cobalt and nickel, and even manganese, from other battery components, especially a composite oxide containing cobalt, nickel, and manganese as a positive electrode active material.

[0023] Solutions to the Problems

[0024] To solve the above problems, the present inventors conducted intensive research repeatedly, and as a result, found that: cobalt and nickel, which are positive electrode active materials contained in a lithium ion secondary battery, although exist in the form of oxides containing cobalt, nickel, manganese, and lithium, by performing heat treatment under specific conditions based on thermodynamic theory calculations, the cobalt and nickel in the oxides can be converted into metal, while manganese and the like still exist in the form of oxides, so that a metal component with increased concentration (concentrated) of cobalt and nickel can be obtained with high efficiency.

[0025] Based on the above findings of the present inventors, the solution for solving the foregoing problems is as follows. That is:

[0026] <1> A method for concentrating valuable metals contained in a lithium ion secondary battery, characterized in that the concentration method treats a lithium ion secondary battery or its positive electrode material containing at least one element of cobalt and nickel, and concentrates valuable metals including at least one of cobalt and nickel, and includes the following steps:

[0027] A heat treatment step of performing heat treatment on the lithium ion secondary battery or its positive electrode material to form an agglomerate containing at least one valuable metal of cobalt and nickel.

[0028] <2>The method for concentrating valuable metals contained in the lithium ion secondary battery according to <1>, wherein, in the heat treatment step, the lithium ion secondary battery or its positive electrode material is heat-treated in a reducing atmosphere or an inert atmosphere.

[0029] <3>The method for concentrating valuable metals contained in the lithium ion secondary battery according to <1> or <2>, wherein, in the heat treatment step, the lithium ion secondary battery is heat-treated in a state of being housed in a casing having a melting point above the heat treatment temperature.

[0030] <4>The method for concentrating valuable metals contained in the lithium ion secondary battery according to <3>, wherein the casing is an outer casing of a battery pack, module or battery cell of the lithium ion secondary battery.

[0031] <5>The method for concentrating valuable metals contained in the lithium ion secondary battery according to any one of <1> to <4>, wherein, in the heat treatment step, heat treatment is performed in a state where carbon is present in an amount of 10% by mass or more based on the total mass% of at least one of cobalt and nickel contained in the lithium ion secondary battery or its positive electrode material.

[0032] <6>The method for concentrating valuable metals contained in the lithium ion secondary battery according to <5>, wherein the carbon contains carbon derived from the negative electrode material of the lithium ion secondary battery.

[0033] <7>The method for concentrating valuable metals contained in the lithium ion secondary battery according to any one of <1> to <6>, further comprising the following steps:

[0034] A crushing step of crushing the heat-treated product of the lithium ion secondary battery or its positive electrode material obtained by the heat treatment step;

[0035] A screening step of screening and recovering a product concentrated with at least any one of cobalt and nickel from the crushed product of the heat-treated product obtained by the crushing step.

[0036] <8>The method for concentrating valuable metals contained in the lithium ion secondary battery according to <7>, wherein the screening step includes:

[0037] A first screening step of classifying the crushed product obtained by the crushing step using a sieve having a sieve hole of 0.1 mm to 2.4 mm into a coarse-grained product and a fine-grained product;

[0038] A second screening step of separating the fine-grained product obtained in the first screening step using at least any one of differences in magnetism, particle size, and specific gravity.

[0039] <9>The method for concentrating valuable metals contained in the lithium-ion secondary battery according to <8>, which includes a micronization step of further micronizing the fine particle product obtained in the first screening step,

[0040] Performing the second screening step on the micronized material obtained in the micronization step.

[0041] <10>The method for concentrating valuable metals contained in the lithium-ion secondary battery according to <9>, wherein the cumulative 50% volume particle size D of the micronized material 50 is 75 μm or less.

[0042] <11>The method for concentrating valuable metals contained in the lithium-ion secondary battery according to any one of <7> to <10>, wherein the screening step is a magnetic separation step, and the magnetic flux density of the magnet in the magnetic separation step is 0.01 tesla or more and 2 tesla or less.

[0043] <12>The method for concentrating valuable metals contained in the lithium-ion secondary battery according to <11>, wherein the magnetic separation step is a wet magnetic separation.

[0044] <13>The method for concentrating valuable metals contained in the lithium-ion secondary battery according to <12>, wherein a dispersant of 50 mg / L or more is added to the slurry applicable in the wet magnetic separation.

[0045] <14>The method for concentrating valuable metals contained in the lithium-ion secondary battery according to <12> or <13>, wherein the slurry applicable in the wet magnetic separation is subjected to ultrasonic-based particle dispersion treatment.

[0046] <15>The method for concentrating valuable metals contained in the lithium-ion secondary battery according to any one of <1> to <14>, wherein in the heat treatment step, heat treatment is performed at 750 °C or more and 1200 °C or less for 1 hour or more.

[0047] <16>A method for concentrating valuable metals contained in a lithium-ion secondary battery, characterized in that the concentrating method treats a lithium-ion secondary battery or its positive electrode material containing at least one element of cobalt and nickel, and concentrates valuable metals including at least one of cobalt and nickel, and includes the following steps:

[0048] A heat treatment step of heating the lithium-ion secondary battery or its positive electrode material to 600 °C to 1200 °C;

[0049] A crushing and classification step of crushing and classifying the heat-treated material obtained in the heat treatment step;

[0050] A reheat treatment process, in which the fine-grained product obtained in the crushing and classification process is reheated to 300°C to 1200°C to form a granular mass containing at least one valuable metal among cobalt and nickel.

[0051] <17> The method for concentrating valuable metals contained in the lithium-ion secondary battery according to <16>, wherein the negative electrode material in the lithium-ion secondary battery contains carbon.

[0052] <18> The method for concentrating valuable metals contained in the lithium-ion secondary battery according to <16> or <17>, characterized by including: a screening process, in which a product concentrated with at least any one of cobalt and nickel is screened and recovered from the reheat-treated product obtained through the reheat treatment process.

[0053] <19> The method for concentrating valuable metals contained in the lithium-ion secondary battery according to <18>, characterized by recovering, in the screening process, a product concentrated with at least any one of cobalt and nickel, and a product concentrated with manganese.

[0054] <20> The method for concentrating valuable metals contained in the lithium-ion secondary battery according to <18> or <19>, wherein the screening process is a process of separating using at least any one of differences in magnetism, particle size, and specific gravity.

[0055] <21> The method for concentrating valuable metals contained in the lithium-ion secondary battery according to any one of <16> to <20>, wherein in the heat treatment process, the lithium-ion secondary battery is housed in an aluminum-containing casing, and aluminum from the casing is separated during heating.

[0056] <22> The method for concentrating valuable metals contained in the lithium-ion secondary battery according to any one of <16> to <21>, wherein in the crushing and classification process, crushing based on impact, shear, or compression is performed, and classification is performed using a sieve with a sieve aperture of 0.1 mm to 2.4 mm.

[0057] <23> The method for concentrating valuable metals contained in the lithium-ion secondary battery according to any one of <16> to <22>, wherein in the reheat treatment process, the cumulative 50% volume particle size D of the granular mass containing at least one metal among cobalt and nickel 50 is 1 μm or more.

[0058] <24> The method for concentrating valuable metals contained in the lithium-ion secondary battery according to any one of <18> to <23>, wherein the screening process is a magnetic separation process, and the magnetic flux density of the magnet in the magnetic separation process is 0.01 tesla or more and 2 tesla or less.

[0059] <25> The method for concentrating valuable metals contained in the lithium ion secondary battery according to <24>, wherein the magnetic separation step is wet magnetic separation, and a dispersant of 50 mg / L or more is added to the applicable slurry.

[0060] <26> The method for concentrating valuable metals contained in the lithium ion secondary battery according to <25>, wherein the slurry applicable to the wet magnetic separation is subjected to ultrasonic-based particle dispersion treatment.

[0061] <27> The method for concentrating valuable metals contained in the lithium ion secondary battery according to any one of <16> to <26>, wherein a reducing component is added in at least one of the heat treatment step and the reheat treatment step to form a reducing atmosphere.

[0062] <28> The method for concentrating valuable metals contained in the lithium ion secondary battery according to any one of <16> to <27>, characterized in that in the heat treatment step or the reheat treatment step, a part of the heat treatment time is heated in an air atmosphere or an oxidizing atmosphere to reduce the grade of the reducing component of the heat-treated product or the reheat-treated product.

[0063] <29> The method for concentrating valuable metals contained in the lithium ion secondary battery according to any one of <18> to <28>, wherein a re-crushing step of re-crushing the heat-treated product is performed after the reheat treatment step and before the screening step.

[0064] <30> The method for concentrating valuable metals contained in the lithium ion secondary battery according to any one of claims <16> to <29>, wherein a magnetic separation step using magnetism is performed on the fine particle product obtained in the crushing and classification step, and the magnetic adsorbent obtained in the magnetic separation step is subjected to the reheat treatment step.

[0065] Effects of the Invention

[0066] According to the first embodiment of the present invention, a method for concentrating valuable metals contained in a lithium ion secondary battery can be provided. Since the lithium ion secondary battery or its positive electrode material is heat-treated to form a lump containing at least one valuable metal of cobalt and nickel, a metal component concentrated with cobalt and nickel can be easily obtained and is easily separated from other battery constituent components.

[0067] In addition, according to the second embodiment of the present invention, a method for concentrating valuable metals contained in a lithium ion secondary battery can be provided. Since the heat treatment at a specified temperature is followed by crushing and classification and then reheat treatment, a metal component concentrated with cobalt and nickel can be easily obtained and is easily separated from other battery constituent components.

[0068] In other words, according to the present invention, a method for concentrating valuable metals contained in a lithium-ion secondary battery can be provided. This method targets used lithium-ion secondary batteries, the positive electrode materials of used lithium-ion secondary batteries, or their process waste materials, etc., and can easily obtain a metal component concentrated with cobalt and nickel, and it is easy to separate cobalt and nickel, and even manganese, from other battery components, especially a composite oxide containing cobalt, nickel, and manganese as a positive electrode active material. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 A scanning electron microscope (SEM, manufactured by Hitachi High-Technologies Corporation, TM4000Plus) photograph showing an example of a part of the fine-grained product (including the positive electrode material) obtained by heat-treating, crushing, and screening a ternary lithium-ion secondary battery containing cobalt, nickel, and manganese in an embodiment of the present invention. All the SEM photographs in the drawings of this application were taken with the same device.

[0070] Figure 2 An SEM photograph showing another example of a part of the fine-grained product (including the positive electrode material) obtained by heat-treating, crushing, and screening a ternary lithium-ion secondary battery containing cobalt, nickel, and manganese in an embodiment of the present invention.

[0071] Figure 3A An SEM photograph showing an example of a part of the product after reheating at 1000 °C in a carbon-containing state of the fine-grained product (including the positive electrode material) obtained by heat-treating, crushing, and screening a ternary lithium-ion secondary battery containing cobalt, nickel, and manganese in an embodiment of the present invention.

[0072] Figure 3B A graph of the elemental peaks of a granule block based on EDS (energy dispersive X-ray spectrometer, AZtecone manufactured by Oxford Instruments) in an example of the product after reheating at 1000 °C in a carbon-containing state of the fine-grained product (including the positive electrode material) obtained by heat-treating, crushing, and screening a ternary lithium-ion secondary battery containing cobalt, nickel, and manganese in an embodiment of the present invention. All the elemental peaks based on EDS in the drawings of the present invention were obtained with the same device.

[0073] Figure 3C A graph of the elemental peaks of manganese oxide based on EDS (energy dispersive X-ray spectrometer) in an example of the product after reheating at 1000 °C in a carbon-containing state of the fine-grained product (including the positive electrode material) obtained by heat-treating, crushing, and screening a ternary lithium-ion secondary battery containing cobalt, nickel, and manganese in an embodiment of the present invention.

[0074] Figure 3D An SEM photograph showing the granule formation state after 1 hour in a 2-hour reheating in an embodiment of the present invention.

[0075] Figure 4A SEM photograph of an example of the fine-grained product before wet magnetic separation in an embodiment of the present invention.

[0076] Figure 4B Graph showing elemental peaks based on EDS (Energy Dispersive X-ray Spectrometer) of an example of the fine-grained product before wet magnetic separation in an embodiment of the present invention.

[0077] Figure 4C Graph showing elemental peaks based on EDS (Energy Dispersive X-ray Spectrometer) of an example of the fine-grained product before wet magnetic separation in an embodiment of the present invention.

[0078] Figure 5A SEM photograph of an example of the fine-grained product after wet magnetic separation in an embodiment of the present invention.

[0079] Figure 5B Graph showing elemental peaks based on EDS (Energy Dispersive X-ray Spectrometer) of an example of the fine-grained product after wet magnetic separation in an embodiment of the present invention.

[0080] Figure 5C Graph showing elemental peaks based on EDS (Energy Dispersive X-ray Spectrometer) of an example of the fine-grained product after wet magnetic separation in an embodiment of the present invention.

[0081] Figure 6A SEM photograph obtained by photographing an example of the product after micronizing the particles of the metal and oxide mass in an embodiment of the present invention.

[0082] Figure 6B To show a part in an embodiment of the present invention Figure 6A Graph of elemental peaks obtained by collecting particles a metallized with cobalt and nickel in and performing elemental analysis using EDS (Energy Dispersive X-ray Spectrometer).

[0083] Figure 6C To show a part in an embodiment of the present invention Figure 6A Graph of elemental peaks obtained by collecting particles a metallized with cobalt and nickel in and performing elemental analysis using EDS (Energy Dispersive X-ray Spectrometer).

[0084] Figure 7 Graph showing an example of X-ray diffraction peaks showing the original state of the cathode material oxide form without forming metals of cobalt and nickel in Reference Example 1.

[0085] Figure 8 Graph showing an example of X-ray diffraction peaks showing the original state of the cathode material oxide form without forming metals of cobalt and nickel in Reference Example 2.

[0086] Figure 9 A figure showing an example of the results of analyzing, by a thermogravimetric differential thermal analyzer, a substance obtained by mixing carbon and a ternary cathode material at a weight ratio of 3:7 for heat treatment temperature research.

[0087] Figure 10 A figure showing an example of the results of analyzing, by a thermogravimetric differential thermal analyzer, fine-grained products obtained by heat-treating, crushing, and classifying a lithium-ion secondary battery for reheat treatment temperature research. Detailed implementation mode

[0088] In the method for concentrating valuable metals contained in the lithium-ion secondary battery according to the first embodiment of the present invention, a heat treatment process is performed. In this heat treatment process, the lithium-ion secondary battery or its cathode material is heat-treated to form agglomerates containing at least one valuable metal among cobalt and nickel, thereby metallizing at least one of cobalt and nickel and forming agglomerates of valuable metals with increased (concentrated) concentrations of cobalt and nickel.

[0089] In this way, in the first embodiment of the present invention, valuable substances concentrated with at least one of cobalt and nickel are obtained from the lithium-ion secondary battery or its cathode material whose constituent components contain at least one element among cobalt and nickel. At least one of cobalt and nickel is metallized by heat treatment, and then, by performing a crushing process and a screening process, cobalt and nickel are separated from other battery constituent components, and valuable substances with further increased (concentrated) concentrations of cobalt and nickel can be obtained.

[0090] In addition, in the first embodiment of the present invention, it is preferable to perform heat treatment in a reducing atmosphere or an inert atmosphere. In the first embodiment of the present invention, by performing heat treatment in a reducing atmosphere or an inert atmosphere, it is easier to form agglomerates containing at least one valuable metal among cobalt and nickel.

[0091] Here, metallization means that compounds such as oxides containing cobalt and nickel, such as lithium cobaltate (LiCoO 2 ), lithium cobalt nickelate (LiCo 1 / 2 Ni 1 / 2 O 2 ), those called ternary systems or NCM systems such as LiNi x Co y Mn z O 2 (x + y + z = 1), those called NCA systems such as LiNi x Co y Al zCobalt or nickel present in the form of (x + y + z = 1) is converted into metal; for metallization, there are substances that are completely metallized in particulate form and substances that are partially metallized, and it is not necessary to be a pure substance. Thus, the metallization of cobalt or nickel means: becoming a state with a specific gravity close to that of the metal of cobalt or nickel and having magnetism. In addition, the metallized cobalt or nickel can be in the alloy state of cobalt or nickel.

[0092] In the method for concentrating valuable metals contained in the lithium-ion secondary battery according to the second embodiment of the present invention, by performing a heat treatment step, a crushing and classification step, and a reheat treatment step on the lithium-ion secondary battery or its positive electrode material containing at least one element of cobalt and nickel, at least one of cobalt and nickel is metallized to form an agglomerate of valuable metals with an increased (concentrated) concentration of cobalt and nickel. In the heat treatment step, for the positive electrode material present in the form of an oxide containing cobalt, nickel, manganese, and lithium, the heat treatment is performed in a state where it is built into the components of the battery cell, module, and battery pack of the lithium-ion secondary battery. By performing this heat treatment, while suppressing the combustion consumption of carbon in the lithium-ion secondary battery, cobalt and nickel metals can be efficiently formed. The metals of cobalt and nickel form agglomerated particles with oxide particles such as manganese.

[0093] After the heat-treated product obtained in the heat treatment step is crushed and classified, the fine-grained product mainly contains cobalt, nickel, manganese, and carbon. By performing reheat treatment on these powders, using the fine cobalt and nickel metals generated in the heat treatment step as nuclei, cobalt and nickel grow into larger agglomerates (the continuous reduction of the oxides of cobalt and nickel that form aggregates with the fine metals of cobalt and nickel increases the particle size of the fine metals), and in addition, the agglomerates melt / join with each other to further increase the particle size of the agglomerates. As a result, a clear solid-solid interface is formed with the oxides such as manganese that originally formed aggregates. Thus, screening / concentration is facilitated.

[0094] In this way, in the second embodiment, cobalt and nickel metals are formed in the heat treatment step. For this metal, cobalt and nickel are separated from manganese in the crushing and classification step, and the agglomerates of metallized cobalt and nickel grow in the reheat treatment step, thereby enabling the formation of larger agglomerates. Therefore, in the second embodiment, since large agglomerates of metallized cobalt and nickel can be obtained, it is possible to more easily recover the metallized cobalt and nickel.

[0095] Since this reheat treatment step is performed on powders, the contact efficiency between the fine cobalt and nickel metals and oxides and carbon is increased, enabling the formation of the agglomerates. In addition to the formation of the agglomerates, this reheat treatment also causes the combustion of carbon, which can reduce the carbon grade of the product after the reheat treatment.

[0096] If the heat treatment of the previous process is carried out at a temperature lower than 600 °C, since it is difficult to form fine metals of cobalt and nickel during this heat treatment, during the re-heat treatment, the heat treatment is carried out in a state where there is no nucleus for the growth of the cobalt and nickel grain masses. Before the formation of the cobalt and nickel grain masses, carbon is burned and consumed, and it is impossible to form cobalt and nickel grain masses of sufficient size. In addition, cobalt and nickel are in a state where oxides are formed with manganese, etc., and it is difficult to separate cobalt and nickel from manganese by physical screening, and sufficient magnetism cannot be imparted either.

[0097] In the second embodiment of the present invention, for at least one of cobalt and nickel, by carrying out at least a part of the combustion time in an air atmosphere or an oxidizing atmosphere in at least one of the heat treatment process and the re-heat treatment process, the grade of the reducing components of the obtained heat-treated product can be reduced. That is, since the reducing components contained in the heat-treated product are consumed, the mixing of the reducing components into the fine-grained product described below can be avoided.

[0098] (First Embodiment)

[0099] Hereinafter, first, as the first embodiment of the present invention described above, a method of concentrating valuable metals contained in a lithium-ion secondary battery by carrying out a heat treatment process will be described.

[0100] <Heat Treatment Process>

[0101] The heat treatment process is a process of heat-treating a lithium-ion battery (LIB) or its positive electrode material in a reducing atmosphere or an inert atmosphere to form grain masses containing at least one valuable metal of cobalt and nickel.

[0102] As the heat treatment temperature in the heat treatment process, for example, it is preferably 600 °C or higher and 1200 °C or lower, more preferably 700 °C or higher and 1200 °C or lower, and further preferably 750 °C or higher and 1100 °C or lower.

[0103] By setting the heat treatment temperature to 600 °C or higher, the metallization of cobalt and nickel can be carried out efficiently, and by setting the heat treatment temperature to 1200 °C or lower, the energy and cost required for the heat treatment can be suppressed.

[0104] As the heat treatment time, there is no particular limitation, and it can be appropriately selected according to the purpose. It is preferably 30 minutes or longer and 5 hours or shorter, more preferably 1 hour or longer and 3 hours or shorter. The heat treatment time is only required to be the heat treatment time at the desired temperature for the metallization of cobalt and nickel, and the holding time only needs to ensure the time for the development of metallization. When the heat treatment time is within the preferred range, it is advantageous in terms of the cost required for the heat treatment.

[0105] Therefore, it is preferable to perform heat treatment at a temperature of 750 °C or higher and 1200 °C or lower for 1 hour or longer.

[0106] As the method of heat treatment, there is no particular limitation, and it can be appropriately selected according to the purpose. Examples thereof include a method using a heat treatment furnace. Examples of the heat treatment furnace include batch furnaces such as muffle furnaces, tunnel furnaces, rotary kilns, fluidized bed furnaces, cupolas, and stokers.

[0107] The heat treatment can be carried out in an air atmosphere or an oxidizing atmosphere, or in a reducing atmosphere or an inert atmosphere.

[0108] Examples of the reducing atmosphere include an atmosphere with a low oxygen concentration containing hydrogen, carbon monoxide, etc. Specifically, the oxygen concentration can be adjusted to 15% or less.

[0109] Examples of the inert atmosphere include an atmosphere composed of nitrogen or argon. In order to easily obtain pellets in which cobalt and nickel are metallized and concentrated, a reducing component can be further added.

[0110] Thus, in the present invention, when performing heat treatment in an inert atmosphere, it is preferable to perform heat treatment in the presence of a reducing agent. Thereby, the metallization of cobalt and nickel can be efficiently carried out.

[0111] Examples of the reducing agent include carbon, hydrogen, carbon monoxide, hydrocarbon gases, and hydrocarbon compounds. In addition, the carbon as the reducing agent can be carbon derived from the negative electrode material of a lithium ion secondary battery. The addition amount of the reducing component is preferably 0.1% or more in terms of mass ratio with respect to the content of at least one of cobalt and nickel. That is, in the present invention, in the heat treatment step, it is preferable to perform heat treatment in a state where carbon is present in an amount of 10% by mass or more with respect to the total mass% of at least one of cobalt and nickel contained in the lithium ion secondary battery or its positive electrode material.

[0112] Here, when performing heat treatment only in air on compounds such as oxides containing cobalt and nickel, lithium cobaltate (LiCoO 2 ), lithium cobalt nickelate (LiCo 1 / 2 Ni 1 / 2 O 2 ), LiNi x Co y Mn z O 2 (x + y + z = 1), LiNi x Co y Al z (x + y + z = 1), etc., which are called ternary systems or NCM systems, etc., the reaction of metallization of cobalt and nickel hardly proceeds.

[0113] However, there is a trend that even if the oxygen concentration is relatively high to a certain extent, as long as it is at a high temperature, metallization is likely to develop and the particles of metallization will become larger. In this case, the heat treatment temperature is preferably 750°C to 1200°C as described above.

[0114] In addition, even if the oxygen concentration is relatively high to a certain extent, for example, as long as a sufficient amount of reducing agent exists (a reducing atmosphere can be formed), metallization becomes likely to develop.

[0115] As a method for realizing an atmosphere with a low oxygen concentration (low oxygen atmosphere), for example, a lithium ion secondary battery or its positive electrode material can be housed in an oxygen shielding container and subjected to heat treatment.

[0116] As the material of the oxygen shielding container, there is no particular limitation as long as it has durability against the combustion temperature and internal pressure, and it can be appropriately selected according to the purpose. Examples include iron, stainless steel, etc. with a high melting point. Since a lithium ion secondary battery releases gas due to the combustion of the internal electrolyte, resulting in an increase in air pressure, it is preferable to provide an opening in the oxygen shielding container. In this case, the ratio of the opening area of the opening to the surface area of the container provided with the opening, that is, the opening ratio is preferably 12.5% or less, and more preferably 6.3% or less.

[0117] By setting the opening ratio to 12.5% or less, the oxidation of cobalt and nickel caused by roasting can be suppressed, and cobalt and nickel can be metallized more efficiently.

[0118] In addition, by heat-treating the outer packaging case of a battery pack, module, or battery cell of a lithium ion secondary battery together, oxygen can be shielded and cobalt and nickel can be metallized better. That is, in the present invention, as the oxygen shielding container, for example, the outer packaging case of a battery pack, module, or battery cell of a lithium ion secondary battery can be used.

[0119] Thus, in the present invention, in the heat treatment process, it is preferable to heat-treat the lithium ion secondary battery in a state of being housed in a case having a melting point above the heat treatment temperature. As this case, the outer packaging case of a battery pack, module, or battery cell of a lithium ion secondary battery can be preferably used.

[0120] In addition, the cumulative 50% volume particle size D of metallized cobalt and nickel 50 is preferably 1 μm or more, and more preferably 1 μm or more and 5000 μm or less. When the cumulative 50% volume particle size D 50 is 1 μm or more, it has the advantage of being easily separated / concentrated in the subsequent screening process.

[0121] The cumulative 50% volume particle size D 50 can be measured by, for example, a particle size distribution meter, etc.

[0122] Next, although after the above heat treatment, a heat-treated product (LIB heat-treated product) in which metallized cobalt, nickel, and other components are mixed can be obtained, it is preferable to perform a crushing step and a screening step to separate cobalt and nickel, which are valuable substances to be concentrated. Thereby, a state in which cobalt and nickel can be easily separated from other battery components (such as manganese, aluminum, lithium, copper, iron, carbon, etc.) can be achieved.

[0123] <Crushing Step>

[0124] After performing the above heat treatment step, it is preferable to perform a crushing step of crushing the heat-treated product obtained in the heat treatment. In other words, in the present invention, it is preferably further included a crushing step that crushes the heat-treated product of the lithium-ion secondary battery or its positive electrode material obtained by the heat treatment step.

[0125] As the crushing method in the crushing step, there is no particular limitation, and it can be appropriately selected according to the purpose. As a method of crushing by impact, there can be cited a method of throwing with a rotating striking plate and hitting an impact plate to give an impact, a method of hitting the heat-treated product with a rotating striker (paddle), and it can be carried out with, for example, a hammer crusher, a chain crusher, etc. In addition, there can be cited a method of hitting the heat-treated product with balls or rods of ceramics, iron, etc., and it can be carried out with a ball mill, a rod mill, etc. In addition, as a crushing method based on compression, it can be carried out by crushing with a twin-screw crusher having a short blade width and blade length.

[0126] By promoting the crushing of the active material and the current collector through impact and compression, on the other hand, the copper in the current collector is not easily significantly changed in form and exists in the form of a foil or the like. Through this crushing, the positive electrode active material containing cobalt and nickel is separated from the current collectors of iron, stainless steel, aluminum, copper, etc. serving as the casing. A crushed product in a state where these positive electrode active materials and the current collectors of iron, stainless steel, aluminum, and copper can be efficiently separated in the screening step can be obtained.

[0127] In addition, through this crushing step, a state in which a concentrate of cobalt and nickel is separated from the above heat-treated product (LIB heat-treated product) in which metallized cobalt, nickel, and other components are mixed is obtained, and these are preferably 2.4 mm or less.

[0128] As the crushing time in the crushing step, there is no particular limitation, and it can be appropriately selected according to the purpose. The crushing time per 1 kg of the lithium-ion secondary battery is preferably 0.1 second or more and 30 minutes or less, more preferably 0.2 second or more and 10 minutes or less, and particularly preferably 0.3 second or more and 5 minutes or less. By setting the crushing time to 1 second or more and 30 minutes or less, it can be crushed into a size more suitable for classification.

[0129] <Screening Step>

[0130] Preferably, a screening process is carried out after the above-mentioned crushing process. In the screening process, cobalt and nickel are screened from the crushed materials obtained by the crushing process with respect to other cathode active material components containing manganese oxide or aluminum oxide. In other words, preferably, the present invention includes a screening process that screens and recovers a product concentrated with at least any one of cobalt and nickel from the crushed materials of the heat-treated product obtained by the crushing process.

[0131] In addition, as the screening process, as long as it can screen and recover a product concentrated with at least any one of cobalt and nickel from the crushed materials, there is no particular limitation, and it can be appropriately selected according to the purpose. Preferably, it includes a first screening process and a second screening process as follows.

[0132] <<First Screening Process>>

[0133] The first screening process is a process of classifying the crushed materials obtained in the crushing process into a coarse-grained product and a fine-grained product. As the classification method, there is no particular limitation, and it can be appropriately selected according to the purpose. Examples include a vibrating screen, a multi-stage vibrating screen, a hydrocyclone, a standard screen of JIS Z8801, a wet vibrating table, an air table, etc.

[0134] As the screen hole (classification point) in the first screening process, there is no particular limitation, and it can be appropriately selected according to the purpose. Preferably, it is, for example, 0.1 mm or more and 2.4 mm or less, and more preferably 0.6 mm or more and 2.4 mm or less.

[0135] By setting the classification point to 2.4 mm or less, the mixing of metals from the outer container and the metals of the copper current collector into the fine-grained product can be suppressed, and the separation result of cobalt and nickel from the active material can be improved. In addition, by setting the screen hole to 0.1 mm or more, the recovery rate of cobalt and nickel from the active material in the fine-grained product can be increased.

[0136] In addition, when using a screen as the classification method, by placing a fragmentation promoter, such as a stainless steel ball or an alumina ball, on the screen for screening, the small crushed materials attached to the large crushed materials can be separated from the large crushed materials, so that the large crushed materials and the small crushed materials can be efficiently separated. It should be noted that iron is mainly contained in the coarse-grained product.

[0137] It is also possible to classify the crushed materials into a coarse-grained product and a fine-grained product while carrying out the crushing in the form of a crushing and classification process (crushing and classification).

[0138] <<Second Screening Process>>

[0139] The second screening process is a process of separating the fine-grained product obtained in the first screening process using at least any one of magnetic properties, particle size, and specific gravity. By performing the second screening process, valuable metals with increased (concentrated) cobalt and nickel concentrations can be obtained.

[0140] <<Second screening process using magnetic property differences (magnetic separation)>>

[0141] Utilizing the property that cobalt and nickel can be magnetically adsorbed in the elemental metal form, a wet or dry magnetic separation process (dry magnetic separation or wet magnetic separation) can be performed on the fine-grained product obtained in the first screening process. As a result, valuable substances concentrated with metallized (converted to metal) cobalt and nickel can be concentrated in the form of magnetic adsorbates. Products concentrated with manganese, aluminum, lithium, copper, and carbon can be concentrated in the form of non-magnetic adsorbates.

[0142] In addition, the second screening process (magnetic separation) using magnetic property differences can be the same as, for example, the magnetic separation process in the above first embodiment. Therefore, as the second screening process using magnetic property differences, for example, a wet magnetic separation process is preferably used. In addition, the magnetic flux density of the magnet used in magnetic separation is preferably 0.01 tesla or more and 2 teslas or less. By performing magnetic separation using a magnet with a magnetic flux density of 0.02 tesla or more and 2 teslas or less, valuable substances with increased (concentrated) cobalt and nickel concentrations can be obtained.

[0143] For example, for a ternary cathode active material (LiNi x Co y Mn z O 2 (x + y + z = 1)), by performing magnetic separation on the fine-grained product obtained through the crushing process and the first screening process, cobalt and nickel can be separated from manganese, and valuable substances with increased (concentrated) cobalt and nickel concentrations can be obtained.

[0144] Magnetic separation is preferably wet magnetic separation. This is because cross-linking aggregation caused by moisture between particles during dry magnetic separation can be suppressed, the separability of particles is improved, and higher-purity cobalt and nickel can be easily obtained.

[0145] In the wet magnetic separation, a dispersant can be added to the applicable slurry. By adding the dispersant, the separation of cobalt and nickel from other battery components can be promoted. The addition amount of the dispersant is preferably 50 mg / L or more.

[0146] Wet magnetic separation preferably performs ultrasonic-based particle dispersion treatment on the applicable slurry. By performing this ultrasonic-based particle dispersion treatment, the separation of cobalt and nickel from other battery components can be promoted.

[0147] <<Second screening process using particle size and specific gravity (particle size and specific gravity screening)>>

[0148] By further classifying and screening the fine-grained product obtained in the first screening process based on particle size, or by performing specific gravity screening, a valuable substance with increased (concentrated) concentrations of metallized (converted to metal) cobalt and nickel can be obtained.

[0149] The second screening process (particle size and specific gravity screening) using particle size and specific gravity can be carried out using various devices exemplified, for example, as the devices using the classification method and the specific gravity screening method, or the combined principle of these, in the first embodiment above.

[0150] As the device using the classification method and the specific gravity screening method, or the combined principle of these, there is no particular limitation, and it can be appropriately selected according to the purpose. Examples include: dry particle classification devices such as vibrating screens, dry cyclones, turbo classifiers, pneumatic fine classifiers, micron classifiers, elbow jet classifiers, CliffisCF, electrostatic screening devices; wet particle classification devices such as hydrocyclones, Falcon concentrators, Nelson concentrators, multi-gravity concentrators, laboratory concentrators, cross-belt sorters, Kelsey jigs, Ott jigs, high-precision wet classifiers, vertical cylindrical wet classifiers, etc.

[0151] It should be noted that as long as the valuable substance with increased (concentrated) concentrations of cobalt and nickel as the target can be obtained, there is no particular limitation, and the above devices can be appropriately combined and used according to the purpose.

[0152] For example, in the case of a ternary cathode active material (LiNi x Co y Mn z O 2 (x + y + z = 1)), for the fine-grained product obtained in the crushing process and the first screening process, by the method of screening using the specific gravity difference between cobalt and nickel particles and manganese oxide particles, and the method of classifying using the particle size difference between the two, a valuable substance with increased (concentrated) concentrations of cobalt and nickel can also be obtained.

[0153] It should be noted that through the above-mentioned screening based on magnetic separation or specific gravity, screening using particle size differences, or various screenings based on combinations of these, not only can cobalt and nickel be screened from manganese oxide, but also aluminum, lithium, copper, iron, and carbon as other battery components can be separated.

[0154] <Micronization process>

[0155] In addition, in the present invention, before the second screening step, in other words, it is preferable to further perform a micronization step on the fine-grained product obtained through the first screening step. That is, in the present invention, it is preferable to include a micronization step of further micronizing the fine-grained product obtained in the first screening step, and performing the second screening step on the micronized product obtained in the micronization step.

[0156] Thereby, it is possible to suppress the aggregation or mixing of cobalt and nickel metallized (converted into metal) particles with other battery constituent components into a lump, and thus, the monomer separation of cobalt and nickel metals from manganese oxide becomes more highly accurate.

[0157] There is no particular limitation on the micronizer, and it can be appropriately selected according to the purpose. For example, a bead mill, a roll mill, a jet mill, a hammer mill, a needle mill, a rotary mill, a vibration mill, a planetary mill, a grinder, etc. can be used.

[0158] The cumulative 50% volume particle size D of the micronized product obtained in the micronization step 50 is preferably 75 μm or less, more preferably 0.1 μm or more and 75 μm or less, and still more preferably 0.5 μm or more and 53 μm or less. By micronizing to a cumulative 50% volume particle size D 50 of 75 μm or less, the monomer separation of cobalt and nickel metals from other constituents can be promoted.

[0159] By setting the cumulative 50% volume particle size D of the micronized product 50 to 0.1 μm or more, it is possible to prevent the aggregation of cobalt and nickel with other battery constituent components due to crosslinking caused by moisture between particles and electrostatic adsorption force, resulting in a decrease in the separability of the two.

[0160] The cumulative 50% volume particle size D 50 can be measured by, for example, a particle size distribution meter.

[0161] <Other Processes>

[0162] There is no particular limitation on other processes, and they can be appropriately selected according to the purpose. Examples include a valuable substance recovery process, a valuable substance purification process, etc.

[0163] (Second Embodiment)

[0164] Hereinafter, as the second embodiment of the present invention, a method of concentrating valuable metals contained in a lithium ion secondary battery by performing a heat treatment step, a crushing and classification step, and a re-heat treatment step will be described.

[0165] It should be noted that in the second embodiment, the processes other than the heat treatment process and the reheat treatment process in the first embodiment may be the same as those in the first embodiment, and thus the description may sometimes be omitted as needed.

[0166] <Heat Treatment Process>

[0167] In the heat treatment process, the lithium ion secondary battery or its positive electrode material is heated to 600°C to 1200°C.

[0168] From the perspective of thermal decomposition of the electrode material, the heat treatment temperature is preferably heated under the condition of 700°C to 1200°C, more preferably 750°C to 1100°C. When the heat treatment temperature is less than 600°C, the reaction of metallization of cobalt and nickel, which is the main target, is difficult to proceed. In addition, it becomes difficult to melt and separate the aluminum derived from the casing, and the load of the crushing process increases. When the heat treatment temperature exceeds 1200°C, from the perspective of energy and economy, the cost increases. In addition, when it exceeds 1200°C, as another problem, there is also the problem that the copper foil melts and it is difficult to recover the copper foil.

[0169] As the heat treatment time, as long as the molten aluminum can be separated, it can be appropriately selected, preferably 30 minutes or more and 5 hours or less, more preferably 1 hour or more and 3 hours or less. The heat treatment time is preferably the heat treatment time such that no reducing components remain in the obtained heat-treated product. From the perspective of the cost required for heat treatment, heating at 750°C to 1100°C for 1 hour or more is sufficient.

[0170] As the heat treatment method, there is no particular limitation, and it can be appropriately selected according to the purpose. Examples include methods using a heat treatment furnace. As the heat treatment furnace, examples include intermittent furnaces such as muffle furnaces, tunnel furnaces, rotary kilns, fluidized bed furnaces, cupolas, coal-fired furnaces, etc.

[0171] The heat treatment can be carried out in an air atmosphere or an oxidation atmosphere, or in a reduction atmosphere or an inert atmosphere.

[0172] As the reduction atmosphere, examples include an atmosphere with a low oxygen concentration in which hydrogen, carbon monoxide, etc. are present. Specifically, it can be adjusted to an atmosphere with an oxygen concentration of 15% or less.

[0173] As the inert atmosphere, examples include an atmosphere composed of nitrogen or argon. In order to easily obtain agglomerates in which cobalt and nickel are metallized and concentrated, a reducing component can be further added.

[0174] Thus, in the present invention, when the heat treatment is carried out in an inert atmosphere, it is preferably carried out in the presence of a reducing agent. Thereby, the metallization of cobalt and nickel can be efficiently carried out.

[0175] Examples of the reducing agent include carbon, hydrogen, carbon monoxide, hydrocarbon gas, and hydrocarbon compounds. In addition, as the carbon serving as the reducing agent, carbon derived from the negative electrode material of a lithium ion secondary battery can be used. The addition amount of the reducing component is preferably 0.1% or more in terms of mass ratio relative to the content of at least one of cobalt and nickel. That is, in the present invention, in the heat treatment step, it is preferable to perform the heat treatment in a state where carbon is present in an amount of 10% by mass or more relative to the total mass% of at least one of cobalt and nickel contained in the lithium ion secondary battery or its positive electrode material.

[0176] Generally, when heat-treating only compounds such as oxides containing cobalt and nickel, lithium cobaltate (LiCoO 2 ), lithium cobalt nickelate (LiCo 1 / 2 Ni 1 / 2 O 2 ), LiNi x Co y Mn z O 2 (x + y + z = 1), LiNi x Co y Al z (x + y + z = 1), etc., which are called ternary systems or NCM systems, the reaction of metallization of cobalt and nickel hardly progresses.

[0177] However, even in air, sometimes by allowing the carbon of the negative electrode material to function as a reducing component, metallization can be easily developed. Furthermore, in the heat treatment in the high temperature range of 600 to 1200 °C, there are cases where metallization is easily developed and fine grains with a small size of metallization can be obtained.

[0178] In addition, when the outer packaging case of the lithium ion secondary battery is made of aluminum or contains aluminum, from the perspective of concentrating cobalt and nickel in subsequent processes, it is preferable to separate the aluminum derived from the outer packaging case that melts during the heat treatment.

[0179] <Fragmentation and Classification Step>

[0180] Next, after the heat treatment step, a heat-treated product (LIB heat-treated product) can be obtained. This heat-treated product mainly contains valuable metals such as cobalt and nickel and other battery constituent components (manganese, aluminum, lithium, copper, iron, carbon, etc.).

[0181] Therefore, in order to separate cobalt and nickel, which are valuable metals to be concentrated, a fragmentation and classification step is performed to fragment and classify the LIB heat-treated product.

[0182] First, as the fragmentation method, the same method as the fragmentation method in the fragmentation step of the above first embodiment can be adopted.

[0183] Note that, in the case where pellets containing metallized cobalt and nickel are formed in the heat treatment process, the crushing method only needs to crush to the extent that the pellets and other battery constituent components are fragmented. In the present invention, crushing methods such as bead mills, roller mills, jet mills, hammer mills, needle mills, rotary mills, vibration mills, planetary mills, and grinders can be appropriately used.

[0184] As the crushing time, it can be the same as the crushing time in the crushing process of the first embodiment described above.

[0185] Next, by performing classification, the fine-grained product and the coarse-grained product constituting the crushed material obtained in the crushing are separated, where the fine-grained product contains cobalt and nickel; the coarse-grained product contains the outer casing constituent components and other electrode constituent components.

[0186] As the screening method, it is preferable to perform screening with the sieve aperture (classification point) set to, for example, 0.1 mm to 2.4 mm, and the classification point is more preferably 0.6 mm to 2.4 mm.

[0187] By setting the classification point to 2.4 mm or less, the mixing of metals from the outer container and the copper current collector into the fine-grained product can be suppressed, and the separation result of cobalt and nickel from the active material can be improved. In addition, by setting the sieve aperture to 0.1 mm or more, the recovery rate of cobalt and nickel from the active material in the fine-grained product can be increased.

[0188] For classification, for example, dry particulate classification devices such as vibrating screens, JIS Z8801 standard sieves, wet vibrating tables, air tables, dry cyclones, turbo classifiers, pneumatic fine classifiers, micron classifiers, elbow jet classifiers, CliffisCF, electrostatic screening devices, etc. can be used; wet particulate classification devices such as hydrocyclones, Falcon concentrators, Nelson concentrators, multi-gravity concentrators, laboratory concentrators, cross-belt sorters, Kelsey jigs, Ott jigs, high-precision wet classifiers, vertical cylindrical wet classifiers, etc. can be used.

[0189] In addition, when using a sieve as the classification method, by placing fragmentation promoters such as stainless steel balls and alumina balls on the sieve for screening, the small fragmented materials attached to the large fragmented materials can be separated from the large fragmented materials, so that the large fragmented materials and the small fragmented materials can be efficiently separated. Note that iron is mainly contained in the coarse-grained product.

[0190] The crushing and classification process can be carried out, for example, in a process of crushing while classifying the crushed material into a coarse-grained product and a fine-grained product.

[0191] In addition, preferably, a magnetic separation process using magnetism is performed on the fine-grained product obtained in the crushing and classification process, and a re-heat treatment process is performed on the magnetic adsorbent obtained in the magnetic separation process. In other words, preferably, the fine-grained product is subjected to magnetic separation, and the obtained magnetic adsorbent is subjected to a subsequent re-heat treatment process.

[0192] As a result, the abundance ratios of cobalt and nickel as the magnetic adsorbent increase, and it becomes easier to form agglomerates in the re-heat treatment process.

[0193] <Re-heat treatment process>

[0194] Next, in the re-heat treatment process, the fine-grained product obtained through the crushing and classification process is heated. The heating temperature is preferably 300 °C or higher and 1200 °C or lower, more preferably 700 °C or higher and 1100 °C or lower, and particularly preferably 750 °C or higher and 1050 °C or lower.

[0195] As a result, agglomerates of metallized cobalt and nickel contained in the fine-grained product are formed. The higher the temperature of the re-heat treatment, the easier the reaction to form metallized agglomerates progresses. When it is less than 300 °C, the said agglomerates are not formed, and when it exceeds 1200 °C, manganese melts, and substances other than the target product are likely to be incorporated into the agglomerates.

[0196] In addition, in the re-heat treatment process, for example, after passing through the crushing and classification process as the previous process, powders containing cobalt, nickel, and manganese are recovered in the form of fine-grained products, and carbon (derived from the negative electrode material) that acts as a reducing agent is heat-treated again as needed. Therefore, the oxide particles containing cobalt, nickel, and manganese and the carbon particles acting as a reducing agent come into closer contact with each other, and the reduction reaction is likely to occur. As a result, the metallization reaction and the formation of agglomerates are more likely to occur. In contrast, in the heat treatment process performed at the beginning, due to the structure of the battery, the negative electrode that acts as a reducing agent and the positive electrode material containing cobalt and nickel to be reduced are arranged in layers with a separator in between. Therefore, although the pulverization of these materials and the metallization of cobalt and nickel are proceeding, it is difficult for the various powders to come into contact with each other, and the reaction to form agglomerates hardly progresses. In addition, in some lithium-ion secondary batteries, carbon is added as a conductive additive to the positive electrode material. Although this contributes to the reduction reaction, the method of recovering powders containing cobalt, nickel, and manganese in the form of fine-grained products and heat-treating again as needed including carbon (derived from the negative electrode material) that acts as a reducing agent can make contact more likely to occur (the contact probability increases), and the metallization reaction and the formation of agglomerates are more likely to occur.

[0197] Here, the cumulative 50% volume particle size D of the agglomerates containing metallized cobalt and nickel formed in the re-heat treatment 50Preferably 1 μm or more, more preferably 5 μm to 1000 μm. When it is of this size, the agglomerates concentrated with cobalt and nickel can be efficiently recovered in the form of valuable metals. Cumulative volume particle size D 50 When it is 1 μm or more, there is an advantage that the separation / concentration in the subsequent screening process is easy to perform. Cumulative volume particle size D 50 It can be measured by, for example, a particle size distribution meter or the like.

[0198] Specifically, the size of the agglomerate precursor contained in the fine particle product is 0.01 to 1 μm, and the size of the agglomerate obtained by re-heat treatment is preferably 1 to 100 μm.

[0199] As the heating time of the re-heat treatment step, as long as the agglomerates of cobalt and nickel can grow, it can be appropriately selected, preferably 20 minutes or more and 5 hours or less, more preferably 1 hour or more and 3 hours or less. The heat treatment time is preferably the heating time such that no reducing components remain in the obtained heat-treated product.

[0200] In addition, as the atmosphere for the re-heat treatment, similar to the above heat treatment step, from the viewpoints of metallization and agglomerate formation of cobalt and nickel, it is preferably carried out in a reducing atmosphere or an inert atmosphere. Further, in the re-heat treatment, it is preferable to heat in an air atmosphere or an oxidizing atmosphere for a part of the time. Thereby, the reducing components contained in the heat-treated product are consumed, and their mixing into the fine particle product can be avoided.

[0201] In addition, after the re-heat treatment step, a screening step is preferably performed. Thereby, the agglomerates of cobalt and nickel, or any one of them concentrated, can be separately recovered from the re-heat treated product. On the other hand, as the product other than the agglomerates, the product concentrated with manganese can be recovered.

[0202] Typically, the wet or dry magnetic separation process (dry magnetic separation or wet magnetic separation) can be carried out by utilizing the property that cobalt and nickel are magnetically adsorbed in the form of metal monomers.

[0203] Thereby, in the re-heat treatment step, the agglomerates of cobalt and nickel formed by metallization (conversion to metal) of cobalt and nickel contained in the fine particle product can be recovered as magnetic adsorbents. As non-magnetic adsorbents, manganese, aluminum, lithium, copper, and carbon can be recovered.

[0204] In addition, the magnetic flux density of the magnet used in the magnetic separation is preferably 0.01 tesla or more and 2 tesla or less. By performing magnetic separation using a magnet having a magnetic flux density in this range, the agglomerates of valuable metals with increased (concentrated) concentrations of cobalt and nickel can be separated.

[0205] For example, in the ternary cathode active material (LiNi x Co y Mnz O 2 In the case of (x + y + z = 1), by subjecting the heat-treated product obtained by re-heat-treating the fine-grained product obtained by screening under the crushing and classification process to magnetic separation, it is possible to recover, in the form of a magnetic adsorbate, a pellet with an increased (concentrated) concentration of cobalt and nickel.

[0206] The magnetic separation is preferably wet magnetic separation. This is because the cross-linking aggregation caused by moisture between particles during dry magnetic separation can be suppressed, the separability of the particles is improved, and it is easier to obtain higher-purity cobalt and nickel.

[0207] In the wet magnetic separation, a dispersant can be added to the applicable slurry. By adding the dispersant, the separation of cobalt and nickel from other battery components can be promoted. The addition amount of the dispersant is preferably 50 mg / L or more.

[0208] In addition, the wet magnetic separation can also perform ultrasonic-based particle dispersion treatment on the applicable slurry. By performing this ultrasonic-based particle dispersion treatment, the separation of cobalt and nickel from other battery components can be promoted.

[0209] By further classifying based on particle size and performing specific gravity screening instead of the magnetic separation, it is also possible to obtain a valuable material with an increased (concentrated) concentration of metallized (converted to metal) cobalt and nickel.

[0210] As a device using a classification method and a specific gravity screening method, or a composite principle of these, there is no particular limitation, and it can be appropriately selected according to the purpose. Examples include: dry particle classification devices such as vibrating screens, dry cyclones, turbo classifiers, pneumatic fine classifiers, micron classifiers, elbow jet classifiers, CliffisCF, electrostatic screening devices, etc.; wet particle classification devices such as hydrocyclones, Falcon concentrators, Nelson concentrators, multi-gravity concentrators, laboratory concentrators, cross-belt sorters, Kelsey jigs, Ott jigs, high-precision wet classifiers, vertical cylindrical wet classifiers, etc.

[0211] It should be noted that as long as a valuable material with an increased (concentrated) concentration of cobalt and nickel as the target can be obtained, there is no particular limitation, and the above devices can be appropriately combined and used according to the purpose.

[0212] Before the screening process, the heat-treated product after re-heat-treating the fine-grained product can be crushed again.

[0213] Thus, the situation where the agglomerates or mixtures of the cobalt or nickel in the form of metallized (converted to metal) particles with other battery components are reduced. In addition, since cobalt or nickel is a metal, it is difficult to be granulated by re-crushing, while oxides such as manganese are easily granulated by re-crushing. Therefore, impurities other than cobalt or nickel can be selectively crushed. Thus, by performing physical screening such as classification, specific gravity screening, or magnetic separation on the re-crushed material, cobalt and nickel can be concentrated into coarse-grained products, heavy products, or magnetic adsorbates, and the oxides such as manganese that become fine-grained can be separated into fine-grained products, light products, or non-magnetic adsorbates. And, for example, when performing magnetic separation, the separation of the metals of cobalt and nickel from manganese oxides and the like will become more highly accurate.

[0214] The re-crushing can be any crushing that causes fragmentation in a state where the agglomerates of cobalt and nickel in the form of metallized (converted to metal) particles are kept while being mixed with other battery components, and a crusher that meets the target can be appropriately selected. As the crusher, for example, a bead mill, a roller mill, a jet mill, a hammer mill, a needle mill, a rotary mill, a vibration mill, a planetary mill, a grinder, etc. can be used.

[0215] <Other Processes>

[0216] As other processes, there are no particular limitations, and they can be appropriately selected according to the purpose. Examples include a valuable metal recovery process, a valuable metal purification process, etc.

[0217] In the method for concentrating valuable metals contained in the lithium-ion secondary battery of the present invention described above, an example of the raw material as the object is as follows.

[0218] <Lithium-Ion Secondary Battery>

[0219] A lithium-ion secondary battery is a secondary battery that charges and discharges by the movement of lithium ions between a positive electrode and a negative electrode. Examples include: a battery cell that includes a positive electrode, a negative electrode, a separator, an electrolytic solution containing an electrolyte and an organic solvent, and an outer container as a battery case that houses the positive electrode, the negative electrode, the separator, and the electrolytic solution; a module formed by connecting a plurality of battery cells; a battery pack that houses the module in a container, etc.

[0220] There are no particular limitations on the shape, structure, size, material, etc. of the lithium-ion secondary battery, and they can be appropriately selected according to the purpose. As the shape of the lithium-ion secondary battery, examples include a laminated type, a cylindrical type, a button type, a coin type, a square type, a flat type, etc.

[0221] <Positive Electrode, Positive Electrode Current Collector, and Positive Electrode Active Material>

[0222] As the positive electrode, there is no particular limitation as long as the positive electrode material is contained on the positive electrode current collector, and it can be appropriately selected according to the purpose. Regarding the shape of the positive electrode, there is no particular limitation and it can be appropriately selected according to the purpose. Examples include a flat plate shape, a sheet shape, etc.

[0223] Regarding the positive electrode current collector, there is no particular limitation on its shape, structure, size, material, etc., and it can be appropriately selected according to the purpose. Examples of the shape of the positive electrode current collector include a foil shape, etc. Examples of the material of the positive electrode current collector include stainless steel, nickel, aluminum, copper, titanium, tantalum, etc.

[0224] Regarding the positive electrode material, there is no particular limitation and it can be appropriately selected according to the purpose. Examples include a positive electrode material that at least contains a positive electrode active material containing rare valuable metals, and a positive electrode material that contains a conductive agent and an adhesive resin as required. Regarding the rare valuable metals, there is no particular limitation and it can be appropriately selected according to the purpose. It is preferably at least one of cobalt and nickel.

[0225] Examples of the positive electrode active material include lithium cobaltate (LiCoO 2 ), lithium cobalt nickelate (LiCo 1 / 2 Ni 1 / 2 O 2 ), LiNi x Co y Mn z O 2 (x + y + z = 1), which is called a ternary system or NCM system, LiNi x Co y Al z (x + y + z = 1), or a composite of these, etc.

[0226] <Negative electrode, negative electrode current collector, and negative electrode active material>

[0227] As the negative electrode, there is no particular limitation as long as the negative electrode material is contained on the negative electrode current collector, and it can be appropriately selected according to the purpose.

[0228] Regarding the shape of the negative electrode, there is no particular limitation and it can be appropriately selected according to the purpose. Examples include a flat plate shape, a sheet shape, etc.

[0229] Regarding the negative electrode current collector, there is no particular limitation on its shape, structure, size, material, etc., and it can be appropriately selected according to the purpose.

[0230] Examples of the shape of the negative electrode current collector include a foil shape, etc.

[0231] Examples of the material of the negative electrode current collector include stainless steel, nickel, aluminum, copper, titanium, tantalum, etc. Among them, copper is preferred.

[0232] As the negative electrode material, there is no particular limitation, and it can be appropriately selected according to the purpose. Examples include a negative electrode material containing at least a negative electrode active material, and optionally a conductive agent and a binder resin.

[0233] As the negative electrode active material, there is no particular limitation, and it can be appropriately selected according to the purpose. Examples include carbon materials such as carbon black, graphite, carbon fiber, metal carbide, organic matter, and carbide of organic matter, titanate, silicon, or a composite thereof.

[0234] The carbon material as the negative electrode active material can act as a reducing agent in the heat treatment to promote the metallization of cobalt and nickel.

[0235] <Outer container>

[0236] As the material of the outer container (case) of the lithium ion secondary battery, there is no particular limitation, and it can be appropriately selected according to the purpose. Examples include aluminum, resin (plastic), stainless steel, iron, other alloy systems, etc.

[0237] Examples

[0238] Hereinafter, examples of the present invention will be described, but the present invention is not limited to these examples.

[0239] (Example 1)

[0240] As the raw material (object sample) to be processed, 295 kg of a battery pack of a used in-vehicle lithium ion secondary battery was prepared. The positive electrode material contained in the battery was a ternary positive electrode active material with a composition of (LiNi x Co y Mn z O 2 (x + y + z = 1), x = 0.33, y = 0.33, z = 0.33). The negative electrode active material was carbon. The iron outer case of the battery pack was used as the oxygen shielding container.

[0241] The whole of it was heat-treated at 750 °C for 1 hour in a burner-type fixed bed furnace (industrial furnace). The heat-treated product was crushed by a hammer crusher (manufactured by Makino Co., Ltd., HC-20), and then classified by a 1.2 mm vibrating screen to recover 60 kg of the fine-grained product under the sieve. It should be noted that analysis of the composition of the fine-grained product showed that the composition of the fine-grained product was 12% by mass of cobalt, 12% by mass of nickel, and 11% by mass of manganese.

[0242] The scanning electron microscope (SEM) photograph of the fine-grained product is as Figure 1 and Figure 2 shown. Figure 1In the area circled by the circle, the dot-like parts that appear bright (white) are the products of cobalt and nickel metallization. As Figure 1 shown, at this time point, fine grains formed by cobalt and nickel metallization can be confirmed on the surface of the positive electrode material particles. In addition, at this time point, the particle size of the cobalt and nickel metallization is small, and almost all are particles with a size of less than 1 μm. In addition, Figure 2 is an SEM photograph of the coarse-grained product taken in a different field of view from Figure 1 . In the area circled by the dashed line, there are products of cobalt and nickel metallization, and in the area circled by the solid line, there are manganese oxides. As Figure 1 and Figure 2 shown, in the fine-grained product, it can be confirmed that the cobalt and nickel particles exist in the form of particles separated from the manganese oxides.

[0243] It should be noted that in Example 1, the inside of the burner-type fixed-bed furnace is in an oxidizing atmosphere. However, since the iron outer casing of the battery pack is directly used as an oxygen shielding container, and at the same time, carbon used as the negative electrode active material of the lithium-ion secondary battery acts as a reducing agent, the atmosphere inside the outer casing is a reducing atmosphere. Here, in Example 1, regarding the amount of carbon as the reducing agent, there is 135% by mass of carbon relative to the total amount of cobalt and nickel contained in the lithium-ion secondary battery, and heat treatment was carried out in this state.

[0244] Next, a part of the obtained fine-grained product was collected, and the atmosphere was made a reducing atmosphere (put into a container, covered, and in a state where carbon derived from the negative electrode active material exists as a reducing agent), and heat treatment (re-heat treatment) was carried out at 1000 °C for 1 hour to obtain a re-heat treated product. Regarding the amount of carbon contained in the fine-grained product, there is 135% by mass of carbon relative to the total amount of cobalt and nickel contained in the lithium-ion secondary battery, and heat treatment was carried out in this state. As a result, it was confirmed that the fine grains formed by the metallization (converted into metal) of cobalt and nickel contained in the fine-grained product became grain agglomerates.

[0245] That is, as Figure 3A shown in the scanning electron microscope (SEM) photograph, for the area that appears bright and white (solid line) and the area that appears gray (dashed line), a part of each was collected and elemental analysis was carried out using EDS (energy dispersive X-ray spectrometer).

[0246] As a result, as Figure 3B shown, from the peaks obtained from spectrum 179, it can be seen that the area circled by the solid line contains a large amount of cobalt and nickel. On the other hand, as Figure 3C shown, from the peaks obtained from spectrum 180, it can be seen that the area circled by the dashed line contains a large amount of manganese and oxygen.

[0247] In this way, it can be known that in Figure 3AIn the region circled by a solid line, metallized grains mainly composed of cobalt and nickel are formed. Figure 3A In the region circled by a dashed line, manganese oxides based on manganese and oxygen are formed. Additionally, Figure 3A As can be seen from the electron microscope image shown, the grains have grown into blocks with a size of 1 - 10 μm.

[0248] It should be noted that Figure 3D The SEM photograph showing the state after 1-hour heat treatment is presented. It can be confirmed that grains are formed even after 1-hour heat treatment.

[0249] Next, the re-heat-treated product obtained by re-heat treatment is subjected to wet magnetic separation using a drum magnetic separator (manufactured by Eriez Magnetics Japan Co., Ltd., WDL8 laboratory model) at a magnetic flux density of 1500 G (0.15 Tesla), a drum rotation speed of 30 rpm, a solid-liquid ratio of 10%, and a slurry supply speed of 2 L / min to recover the magnetically adsorbed matter and the non-magnetically adsorbed matter slurry. Additionally, in the wet magnetic separation of the re-heat-treated product, a dispersant is added to the slurry of the re-heat-treated product at a level of about 6% relative to the amount of carbon, and on this basis, particle dispersion treatment based on ultrasonic waves is performed.

[0250] As a result, grains containing metallized cobalt and nickel are obtained in the form of magnetically adsorbed matter. It is confirmed that manganese oxides, etc. are separated in the non-magnetically adsorbed matter.

[0251] Figure 4A The scanning electron microscope (SEM) photograph of the fine-grained product before wet magnetic separation is presented. Figure 4A In it, it is confirmed that the region circled by a solid line is grains of cobalt and nickel, and the region circled by a dashed line is manganese oxide.

[0252] That is, for Figure 4A the brighter and whiter regions (solid line) and the grayer and darker regions (dashed line) shown in the electron microscope image, a part of each is collected and elemental analysis is performed using EDS.

[0253] As a result, as Figure 4B shown, from the peaks obtained from spectrum 171, it can be seen that the region circled by a solid line is grains of cobalt and nickel. On the other hand, as Figure 4C shown, from the peaks obtained from spectrum 173, it can be seen that the region circled by a dashed line is manganese oxide. It should be noted that it is speculated that the particles darker than the dashed line region in the electron microscope image are carbon.

[0254] Figure 5A The scanning electron microscope (SEM) photograph of the fine-grained product after wet magnetic separation is presented. Figure 5A In it, it is confirmed that the region circled by a solid line is grains of cobalt and nickel, and the region circled by a dashed line is manganese oxide.

[0255] That is, for Figure 5A In the electron microscope image, a part was collected from each of the brighter and whiter regions (solid line) and the grayer and darker regions (dashed line), and elemental analysis was performed using EDS.

[0256] As a result, as Figure 5B shown, from the peaks obtained in Spectrum 136, it can be seen that the region circled by the solid line is a grain mass of cobalt and nickel. On the other hand, as Figure 5C shown, from the peaks obtained in Spectrum 135, it can be seen that the region circled by the dashed line is manganese oxide. It should be noted that it is speculated that the particles darker than the dashed line region in the electron microscope image are carbon.

[0257] In summary, as Figure 4A shown, in the fine particles before magnetic separation, grain masses of cobalt and nickel and manganese oxides were observed at the same frequency; while as Figure 5A shown, after magnetic separation, the proportion of manganese oxide decreased, and the proportion of grain masses of cobalt and nickel increased compared to before magnetic separation.

[0258] As described above, in Example 1 of the present invention, metallized cobalt and nickel were concentrated from the lithium-ion secondary battery.

[0259] (Example 2)

[0260] In Example 2, except that the product after reheat treatment was further pulverized (micropulverized) and then wet magnetic separation was performed, the same operations as in Example 1 were carried out to obtain concentrates of cobalt and nickel.

[0261] More specifically, in Example 2, the particles in the fine particle product that were lumps of metal and oxide were micropulverized using a vibration mill (manufactured by Retsch GmbH, RS200). The cumulative 50% volume particle size D50 of the micropulverized product after micropulverization was 3.9 μm.

[0262] By performing micropulverization, the metals of cobalt and nickel and manganese oxide can be more accurately separated into monomers. The monomer separation in this case means a state in which the metal particles of cobalt and nickel and the oxide particles of manganese exist separately.

[0263] An SEM photograph taken of an example of the product after micropulverizing the particles of the metal and oxide lumps in the fine particle product is as Figure 6A shown. Figure 6A In, particles a metallized with cobalt and nickel are distributed in the region circled by the dashed line, and particles b of manganese oxide are distributed in the region circled by the solid line.

[0264] Figure 6B To show collecting a part Figure 6AA graph showing the results of elemental analysis of particles a metallized with cobalt and nickel using EDS. Figure 6C To show a part of the collection Figure 6A A graph showing the results of elemental analysis of particles b of manganese oxide using EDS (energy dispersive X-ray spectrometer).

[0265] As Figure 6B and Figure 6C shown, it can be confirmed that cobalt and nickel are concentrated in particles a metallized with cobalt and nickel, and manganese oxide is concentrated in particles b of manganese oxide.

[0266] It should be noted that in Example 2, wet magnetic separation was carried out using a drum magnetic separator in the same manner as in Example 1, and the magnetic adsorbent and non-magnetic adsorbent slurries were recovered. The granulated mass containing metallized cobalt and nickel was recovered in the form of the magnetic adsorbent, and manganese oxide, etc. was recovered in the form of the non-magnetic adsorbent.

[0267] (Example 3)

[0268] In Example 3, heat treatment, crushing, and screening of the battery pack of the lithium-ion secondary battery were carried out in the same manner as in Example 1, and fine-grained products were obtained under the sieve. Then, in Example 3, for the obtained fine-grained products, wet magnetic separation was carried out under the same conditions as in Example 1 (the first time, wet magnetic separation before re-heat treatment) to obtain a magnetic adsorbent. Then, in Example 3, the obtained magnetic adsorbent was re-heat treated under the same conditions as in Example 1, and wet magnetic separation (the second time, corresponding to the wet magnetic separation in Examples 1 and 2) was further carried out on the heat-treated product obtained during the re-heat treatment to obtain a magnetic adsorbent. Here, in this second wet magnetic separation, the magnetic adsorbent and non-magnetic adsorbent slurries were screened using a drum magnetic separator under the same conditions as in Example 1. It should be noted that analysis of the obtained magnetic adsorbent shows that cobalt and nickel are concentrated in the magnetic adsorbent.

[0269] The grades of cobalt, nickel, and manganese in the magnetic adsorbent and non-magnetic adsorbent obtained by the second wet magnetic separation in Example 3 and the recovery rates of cobalt, nickel, and manganese based on wet magnetic separation are shown in Table 1.

[0270] (Example 4)

[0271] In Example 4, except that the temperature of the re-heat treatment was set to 850 °C and the re-heat treated product was micro-crushed under the same conditions as in Example 2, the same operations as in Example 3 were carried out to obtain a concentrate of cobalt and nickel (the magnetic adsorbent in the second wet magnetic separation). The grades of cobalt, nickel, and manganese in the magnetic adsorbent and non-magnetic adsorbent obtained by the second wet magnetic separation in Example 4 and the recovery rates of cobalt, nickel, and manganese based on wet magnetic separation are shown in Table 1.

[0272] Observation with SEM and comparison of the states of the magnetic adsorbents obtained by the second wet magnetic separation in Example 3 and the magnetic adsorbents obtained by the second wet magnetic separation in Example 4 revealed that in Example 3, some agglomerated parts of cobalt and nickel grains grown by reheat treatment and manganese oxides could be observed. In contrast, in Example 4, by crushing the product after reheat treatment, the physical agglomeration state of cobalt and nickel metals and manganese oxides could be more fully eliminated. It can be seen from this that compared with Example 3, the separability of cobalt and nickel from manganese in the wet magnetic separation in Example 4 was further improved. That is, compared with Example 3, Example 4 could recover more cobalt and nickel on the magnetic adsorbent side and more manganese on the non-magnetic adsorbent side.

[0273] (Examples 5 to 7)

[0274] In Examples 5 to 7, except that the temperature of the reheat treatment (850 °C or 1000 °C) and the time of the reheat treatment (1 hour or 4 hours) were changed to the temperatures and times shown in Table 1, the same operations as in Example 4 were carried out to obtain concentrates of cobalt and nickel. The grades of cobalt, nickel, and manganese in the magnetic adsorbents and non-magnetic adsorbents obtained by the second wet magnetic separation in Examples 5 to 7 and the recovery rates of cobalt, nickel, and manganese based on the wet magnetic separation are shown in Table 1. From the results of Examples 5 to 7, it can be seen that it is more preferable for the reheat treatment to have a higher temperature and a longer heat treatment time.

[0275] (Examples 8 and 9)

[0276] In Example 8, except that the fine-grained product passing through the sieve was not subjected to reheat treatment, the same operations as in Example 4 were carried out to obtain concentrates of cobalt and nickel.

[0277] In Example 9, except that the fine-grained product passing through the sieve was not subjected to reheat treatment and micronization based on a vibration mill, the same operations as in Example 4 were carried out to obtain concentrates of cobalt and nickel.

[0278] The grades of cobalt, nickel, and manganese in the magnetic adsorbents and non-magnetic adsorbents obtained by the second magnetic separation in Examples 8 and 9 and the recovery rates of cobalt, nickel, and manganese based on the magnetic separation are shown in Table 1. From the results of Examples 4, 8, and 9, it can be confirmed that by carrying out reheat treatment, the recovery rates and grades of cobalt and nickel in the magnetic adsorbent were further improved. In addition, it can be confirmed that micronization based on a vibration mill or the like was effective in improving the recovery rates and grades of cobalt and nickel in the magnetic adsorbent. From the above results, it can be confirmed that in the present invention, it is more preferable to combine reheat treatment and micronization.

[0279] (Example 10)

[0280] In Example 10, in order to confirm that the positive electrode material product itself in the lithium-ion secondary battery or the waste positive electrode material discharged during the manufacturing process of the lithium-ion secondary battery can also concentrate cobalt and nickel and separate manganese in the same manner as in the above examples, a positive electrode material (a reagent of a ternary positive electrode material used in a lithium-ion secondary battery (LiNi x Co y Mn z O 2 (x + y + z = 1), x = 0.33, y = 0.33, z = 0.33)) was used as the object for treatment.

[0281] In Example 10, first, carbon was added to the above positive electrode material, and heat treatment was carried out at 1000 °C for 1 hour in a reducing atmosphere (after being placed in a container and covered, with the presence of carbon as a reducing agent) (corresponding to the re-heat treatment in Examples 1 to 10). In Example 10, it was confirmed that after the heat treatment of the positive electrode material, it was found that cobalt and nickel formed metallic lumps.

[0282] Next, in Example 10, for the positive electrode material after heat treatment, wet magnetic separation was carried out in the same manner as in Example 2 (screening of the magnetic adsorbate and non-magnetic adsorbate slurries using a drum magnetic separator). Then, the obtained magnetic adsorbate was observed, and it was confirmed that cobalt and nickel had been concentrated.

[0283] (Examples 11 to 14)

[0284] In Examples 11 to 14, a lithium-ion secondary battery pack using LMO (a manganese-based positive electrode material using lithium manganate) as the positive electrode material was used as the object for treatment.

[0285] In addition, in Example 11, except that wet magnetic separation (the first wet magnetic separation in Example 9) was not carried out on the fine-grained product screened from the undersize of the crushed product after heat treatment of the lithium-ion secondary battery pack, and in addition, when wet magnetic separation was carried out on the re-heat treated product obtained by re-heat treatment, ultrasonic-based particle dispersion treatment was not carried out and no dispersant was added, the same operations as in Example 9 were carried out to obtain a concentrate of cobalt and nickel.

[0286] In Example 12, except that wet magnetic separation (the first wet magnetic separation in Example 9) was not carried out on the fine-grained product screened from the undersize of the crushed product after heat treatment of the lithium-ion secondary battery pack, and in addition, ultrasonic-based particle dispersion treatment was not carried out when wet magnetic separation was carried out on the re-heat treated product obtained by re-heat treatment, the same operations as in Example 9 were carried out to obtain a concentrate of cobalt and nickel.

[0287] In Example 13, the same operations as in Example 9 were performed, except that the fine-grained product screened from the undersize of the crushed product after heat treatment of the lithium-ion secondary battery pack was not subjected to wet magnetic separation (the first wet magnetic separation in Example 9), and in addition, no dispersant was added when wet magnetic separation was performed on the re-heat-treated product obtained by re-heat treatment, to obtain concentrates of cobalt and nickel.

[0288] In Example 14, the same operations as in Example 9 were performed, except that the fine-grained product screened from the undersize of the crushed product after heat treatment of the lithium-ion secondary battery pack was not subjected to wet magnetic separation (the first wet magnetic separation in Example 9), to obtain concentrates of cobalt and nickel.

[0289] Based on the results of Examples 11 to 14, the effects of ultrasonic-based particle dispersion treatment and addition of a dispersant on the grades of cobalt and nickel obtained by wet magnetic separation were evaluated. The grades of cobalt, nickel, and manganese in the magnetic adsorbate and non-magnetic adsorbate obtained by wet magnetic separation in Examples 11 to 14 and the recoveries of cobalt, nickel, and manganese based on wet magnetic separation are shown in Table 1. From these results, it was confirmed that in order to improve the grades of cobalt and nickel obtained by wet magnetic separation, it is more preferable to use ultrasonic waves and a dispersant in combination.

[0290] (Example 15)

[0291] In Example 15, the same operations as in Example 14 were performed, except that the fine-grained product screened from the undersize of the crushed product obtained by crushing and classifying the heat-treated product obtained by heat treatment was finely pulverized using a vibration mill under the same conditions as in Example 8, to obtain concentrates of cobalt and nickel.

[0292] The grades of cobalt, nickel, and manganese in the magnetic adsorbate and non-magnetic adsorbate obtained by wet magnetic separation in Example 15 and the recoveries of cobalt, nickel, and manganese based on wet magnetic separation are shown in Table 1. Compared with Example 14, in Example 15, the grades of cobalt and nickel in the magnetic adsorbate were further improved.

[0293] (Example 16)

[0294] In Example 16, the same operations as in Example 7 were performed, except that the lithium-ion secondary battery pack using LMO as the positive electrode material was used as the treatment object, and the fine-grained product screened from the undersize of the crushed product after heat treatment of the lithium-ion secondary battery pack was not subjected to wet magnetic separation (the first wet magnetic separation in Example 7), to obtain concentrates of cobalt and nickel.

[0295] The grades of cobalt, nickel, and manganese in the magnetic adsorbate and non-magnetic adsorbate obtained by wet magnetic separation in Example 16, as well as the recovery rates of cobalt, nickel, and manganese based on wet magnetic separation, are shown in Table 1. In Example 16, the grades of cobalt and nickel reached the highest compared with Examples 11 to 15. From this result, it can be seen that it is preferable to perform reheat treatment in a reducing atmosphere as in Example 7, then perform fine pulverization using a vibration mill, and then perform ultrasonic-based particle dispersion treatment on the heat-treated product after fine pulverization, and perform wet magnetic separation using a dispersant to concentrate cobalt and nickel.

[0296] (Examples 17 and 18)

[0297] In Example 17, a lithium-ion secondary battery pack using LMO as the positive electrode material was heat-treated and crushed under the same conditions as in Example 1. The product obtained by collecting the dust containing cobalt and nickel generated during crushing was finely pulverized using a vibration mill, and then wet magnetic separation was performed in the same manner as in Example 1 to obtain a concentrate of cobalt and nickel.

[0298] In addition, in Example 18, except that a lithium-ion secondary battery pack using LMO as the positive electrode material was heat-treated and crushed under the same conditions as in Example 1, and the product obtained by collecting the dust containing cobalt and nickel generated during crushing was reheat-treated under the condition that the reheat treatment time was 4 hours, the subsequent treatment after reheat treatment was performed in the same manner as in Example 2 to obtain a concentrate of cobalt and nickel.

[0299] The grades of cobalt, nickel, and manganese in the magnetic adsorbate and non-magnetic adsorbate obtained by wet magnetic separation in Examples 17 and 18, as well as the recovery rates of cobalt, nickel, and manganese based on wet magnetic separation, are shown in Table 1. From these results, it can be confirmed that the collected dust generated during crushing also contains cobalt and nickel metals, and they can be concentrated. In addition, it can be confirmed that by reheat treatment, the grain lumps of cobalt and nickel can grow, and cobalt and nickel can be further concentrated.

[0300] (Reference Example 1)

[0301] In Reference Example 1, except for performing heat treatment in an oxidizing atmosphere, the same treatment as in Example 10 was performed to confirm whether cobalt and nickel metals were generated. It was confirmed by using an X-ray diffractometer (manufactured by Rigaku Corporation, UltimaIV) on the fine-grained product after heat treatment that only the peaks of LiNi x Co y Mn z O 2 (x + y + z = 1), x = 0.33, y = 0.33, z = 0.33) were confirmed, and the peaks of cobalt and nickel metals were not confirmed. That is, it was confirmed that cobalt and nickel were oxidized and were in an oxide state, and metal grain lumps were not formed, and they could not be screened by magnetic force.

[0302] Figure 7 The X-ray diffraction peaks (spectra) in Reference Example 1, where no metals of cobalt and nickel were formed and the positive electrode material oxide remained in its original state, are shown.

[0303] (Reference Example 2)

[0304] In Reference Example 2, except that the heat treatment temperature during heat treatment was set to 550 °C, the same treatment as in Example 10 was carried out to confirm whether metals of cobalt and nickel were generated. The fine-grained product after heat treatment was confirmed using an X-ray diffractometer (manufactured by Rigaku Corporation, Ultima IV), and it was confirmed that peaks of LiNi x Co y Mn z O 2 (x + y + z = 1), x = 0.33, y = 0.33, z = 0.33) and peaks of carbon were detected, and no peaks of metals of cobalt and nickel were confirmed. That is, it was confirmed that the state where metal lumps were not formed (or basically not formed) could not be screened by magnetism.

[0305] Figure 8 The X-ray diffraction peaks (spectra) in Reference Example 2, where no metals of cobalt and nickel were formed and the positive electrode material oxide remained in its original state, are shown.

[0306] [Table 1]

[0307]

[0308] In addition, the following Tables 2 to 5 show the summary of the treatment conditions and the like of each example.

[0309] [Table 2]

[0310]

[0311] [Table 3]

[0312]

[0313] [Table 4]

[0314]

[0315] [Table 5]

[0316]

[0317] (Study on heat treatment temperature)

[0318] Regarding the heat treatment temperature of the battery pack, from 750 °C to 1200 °C, the formation of metals of cobalt and nickel was confirmed using a thermogravimetric differential thermal analyzer (manufactured by Rigaku Corporation).

[0319] Specifically, a thermogravimetric differential thermal analyzer was used to analyze a mixture of carbon and a ternary cathode material (with a molar ratio of cobalt, nickel, and manganese of 1:1:1) at a weight ratio of 3:7. As the measurement conditions, the measurement was carried out under a nitrogen atmosphere and a heating rate of 20 °C / minute.

[0320] Figure 9 The figure shows the results of the analysis of the mixture of carbon and the ternary cathode material at a weight ratio of 3:7, based on a thermogravimetric differential thermal analyzer, for studying the heat treatment temperature. Figure 7 In the figure, the vertical axis represents the change in mass (Weight: TG curve) and the temperature difference (Heat Flow; DTA curve), and the horizontal axis represents the temperature.

[0321] It can be seen that in Figure 9 the example shown, endothermic absorption starts from around 400 °C, and weight loss starts from around 750 °C. The state where weight loss occurs simultaneously with the endothermic reaction is a characteristic of the reduction reaction. From this, it can be speculated that a reduction reaction caused by carbon, which is a reagent of the cathode material as the analysis object, has occurred. As the possible reactions in this example, the following reactions can be considered:

[0322] 2LiMO 2 +C→Li 2 O+2MO+CO

[0323] MO+C→M+CO

[0324] (where M is a complex or any monomer of cobalt, nickel, and manganese)

[0325] From this, it can be considered that in order to promote the metallization of cobalt and nickel by utilizing the reduction reaction caused by contact with carbon, it is preferable to carry out the heat treatment under conditions of 750 °C or higher.

[0326] (Study on the reheat treatment temperature)

[0327] Next, for the reheat treatment temperature at which cobalt and nickel metallization occurs, verification was carried out in the above thermogravimetric differential thermal analyzer. In this verification, after heat treating, crushing, and sieving (grading) a lithium-ion secondary battery as a specimen (object), the fine-grained product screened out under the sieve was supplied to the thermogravimetric differential thermal analyzer. The measurement atmosphere at this time was assumed to be a reduction atmosphere based on the lid, similar to the above embodiment, not a completely air-free condition. Although oxygen was not actively provided, oxygen was present around the specimen, and due to the coexistence of carbon in powder form, it became a reduction atmosphere, and the measurement was carried out under an air atmosphere in such a state. The heating rate was 20 °C / minute.

[0328] Figure 10The results of thermogravimetric differential thermal analyzer analysis of the fine-grained product obtained by heat-treating, crushing, and classifying a lithium-ion secondary battery for studying the reheat treatment temperature are shown.

[0329] As Figure 10 shown, it was confirmed that starting from the position above 300 °C, weight loss and exothermic reactions occurred, and carbon burned. At this time, CO (carbon monoxide) generated by the combustion caused the reduction of cobalt and nickel compounds, and the metallization reaction developed. As the reactions that may occur in this example, the following reactions can be considered:

[0330] 2C + O 2 → 2CO

[0331] MO + CO → M + CO 2

[0332] (where M is a complex or any monomer of cobalt, nickel, and manganese)

[0333] Therefore, it can be considered that it is preferable to perform the reheat treatment under conditions above 300 °C.

Claims

1. A method for concentrating valuable metals contained in a lithium-ion secondary battery, characterized in that, the concentration method processes a lithium-ion secondary battery or its positive electrode material containing at least one element of cobalt and nickel and containing manganese, and concentrates valuable metals including at least one of cobalt and nickel, which comprises the following steps: A heat treatment step of heating the lithium-ion secondary battery or its positive electrode material to 600°C to 1200°C; A crushing and classification step of crushing and classifying the heat-treated product obtained in the heat treatment step; A re-heat treatment step of reheating the fine-grained product obtained in the crushing and classification step to 700°C to 1100°C to form a lump containing at least one valuable metal of cobalt and nickel while maintaining manganese in an oxidized state.

2. The method for concentrating valuable metals contained in a lithium-ion secondary battery according to claim 1, wherein, the negative electrode material in the lithium-ion secondary battery contains carbon.

3. The method for concentrating valuable metals contained in a lithium-ion secondary battery according to claim 1 or 2, characterized in that, it includes: A screening step of screening and recovering a product concentrated with at least any one of cobalt and nickel from the re-heat treated product obtained through the re-heat treatment step.

4. The method for concentrating valuable metals contained in a lithium-ion secondary battery according to claim 3, characterized in that, in the screening step, a product concentrated with at least any one of cobalt and nickel, and a product concentrated with manganese are recovered.

5. The method for concentrating valuable metals contained in a lithium-ion secondary battery according to claim 3, wherein, the screening step is a step of separating using at least any one difference of magnetism, particle size, and specific gravity.

6. The method for concentrating valuable metals contained in a lithium-ion secondary battery according to claim 1 or 2, wherein, in the heat treatment step, the lithium-ion secondary battery is housed in a housing containing aluminum, and aluminum derived from the housing is separated during heating.

7. The method for concentrating valuable metals contained in a lithium-ion secondary battery according to claim 1 or 2, wherein, in the crushing and classification step, crushing based on impact, shear, or compression is performed, and classification is performed using a sieve with a sieve hole of 0.1 mm to 2.4 mm.

8. The method for concentrating valuable metals contained in a lithium-ion secondary battery according to claim 1 or 2, wherein, In the reheat treatment step, the cumulative 50% volume particle size D of the pellets containing at least one metal of cobalt and nickel 50 is 1 μm or more.

9. The method for concentrating valuable metals contained in a lithium-ion secondary battery according to claim 3, wherein, the screening step is a magnetic separation step, and the magnetic flux density of the magnet in the magnetic separation step is 0.01 tesla or more and 2 tesla or less.

10. The method for concentrating valuable metals contained in a lithium-ion secondary battery according to claim 9, wherein, the magnetic separation step is a wet magnetic separation, and a dispersant of 50 mg / L or more is added to the applicable slurry.

11. The method for concentrating valuable metals contained in a lithium-ion secondary battery according to claim 10, wherein, particle dispersion treatment based on ultrasonic waves is performed on the slurry applicable to the wet magnetic separation.

12. The method for concentrating valuable metals contained in a lithium-ion secondary battery according to claim 1 or 2, wherein, A reducing atmosphere is formed by adding a reducing component in at least one of the heat treatment process and the re-heat treatment process.

13. The method for concentrating valuable metals contained in the lithium ion secondary battery according to claim 1 or 2, wherein, in the heat treatment process or the re-heat treatment process, a part of the heat treatment time is heated in an air atmosphere or an oxidizing atmosphere to reduce the grade of the reducing component of the heat-treated product or the re-heat-treated product.

14. The method for concentrating valuable metals contained in the lithium ion secondary battery according to claim 3, wherein, a re-crushing process of re-crushing the heat-treated product is performed after the re-heat treatment process and before the screening process.

15. The method for concentrating valuable metals contained in the lithium ion secondary battery according to claim 1 or 2, wherein, a magnetic separation process using magnetism is performed on the fine particle product obtained in the crushing and classification process, and the re-heat treatment process is performed on the magnetic adsorbate obtained in the magnetic separation process.

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