Methods for separating valuable materials.

Abstract

DEPCT6720 / 02 / 2567 Methods for separating valuable materials include heat treatment procedures. Perform thermal treatment on lithium-ion secondary batteries that include valuable materials. The compaction process of the product, which is heat-treated during the manufacturing process. With heat, and a classification process that includes the first classification step of the classification. The product is compressed during the compaction process, resulting in coarse particle products. The intermediate products at the intersection point are classified as 0.6 mm or more and 2.4 mm or more. Even less, and the second classification step of the intermediate product classification into products. Medium particles and fine particle products are excluded at the cut-off point in the classification of 40 micrometers. Or more, and 300 micrometers or less;

Description

How to sort valuables

[0001] The present invention relates to a method for sorting valuable materials.

[0002] Lithium ion secondary batteries are lighter, have a larger capacity, and have a higher electromotive force than conventional lead-acid batteries and nickel-cadmium secondary batteries, and are used in personal computers, electric vehicles, portable devices, and the like.

[0003] As the use of lithium-ion secondary batteries is expected to continue to expand, from the perspective of resource recycling, it is desirable to recover valuable materials from lithium-ion secondary batteries that are discarded due to defective products generated during the manufacturing process or due to the end of the life of the devices they are used in or the batteries. When recovering valuable materials such as cobalt, nickel, manganese, aluminum, iron, and copper from lithium-ion secondary batteries, it is important to separate and sort the various metals and impurities used in the lithium-ion secondary batteries in order to increase the value of the recovered materials.

[0004] As a technique for recovering valuable materials from lithium-ion secondary batteries, a technique has been proposed in which lithium-ion secondary batteries are heated, crushed, and classified, and the fine product is subjected to wet magnetic separation to concentrate and recover cobalt, nickel, and the like (see, for example, Patent Document 1). Another technique has been proposed in which magnetized materials such as cobalt and nickel are separated from non-magnetized materials such as copper by heating and crushing the batteries and then subjecting the resulting crushed material to magnetic separation (see, for example, Patent Document 2). Another technique has been proposed in which lithium-ion secondary batteries are heated, crushed, and subjected to two-stage classification, and the intermediate-particle-size product obtained by the classification is subjected to dry magnetic separation to concentrate and recover cobalt, nickel, and the like (see, for example, Patent Document 3).

[0005] However, in the conventional techniques described above, for example, cobalt, nickel, and iron are magnetic materials, and when cobalt and nickel are recovered using magnetic force, iron may also be recovered and mixed in. This has led to the problem of high iron content in valuable materials enriched with cobalt and nickel from the resulting lithium-ion secondary battery. Furthermore, there has been a problem that non-magnetic materials such as copper and aluminum, if present in large amounts, are also entangled and recovered together with the magnetic materials during magnetic separation. There has also been a problem of low recovery rates of cobalt and nickel in intermediate particle sizes.

[0006] Patent No. 6748274 Patent No. 6268130 Patent No. 6676124

[0007] The present invention aims to solve the above-mentioned problems in the prior art and to achieve the following object: That is, the present invention aims to provide a method for separating valuable materials, which can easily separate cobalt and nickel from iron and copper from a lithium ion secondary battery and can obtain high-quality valuable materials with increased concentrations of cobalt and nickel at a high recovery rate.

[0008] Means for solving the above problems are as follows: <1> A method for separating valuable resources, comprising: a heat treatment step of heat-treating lithium-ion secondary batteries containing valuable resources; a crushing step of crushing the heat-treated material obtained in the heat treatment step; and a classification step including: a first classification step of classifying the crushed material obtained in the crushing step into a coarse product and an intermediate product at a classification point of 0.6 mm to 2.4 mm, and a second classification step of classifying the intermediate product into a medium product and a fine product at a classification point of 40 μm to 300 μm. <2> The method for separating valuable resources according to <1>, wherein the crushed material obtained in the crushing step is classified into a coarse product and an intermediate product at a classification point of 1.2 mm in the first classification step. <3> The method for separating valuable resources according to any one of <1> or <2>, wherein the lithium-ion secondary batteries are heat-treated at a temperature of 660°C to 1,085°C in the heat treatment step. <4> The method for sorting valuable resources according to any one of <1> to <3>, wherein in the second classification step, the intermediate product is wet classified at a classification point of 40 μm or more and 75 μm or less. <5> The method for sorting valuable resources according to any one of <1> to <4>, wherein the lithium ion secondary battery is a lithium ion secondary battery pack selected from those for vehicles, power storage systems, and uninterruptible power supplies.

[0009] According to the present invention, it is possible to solve the various problems of the prior art, and to provide a method for separating valuable materials that can easily separate cobalt and nickel from iron and copper from lithium ion secondary batteries, and that can obtain high-quality valuable materials with increased concentrations of cobalt and nickel at a high recovery rate.

[0010] FIG. 1 is a flow chart showing an example of a method for sorting valuable resources according to the present invention.

[0011] (Method for Sorting Valuable Resources) The method for sorting valuable resources of the present invention includes a heat treatment step, a crushing step, and a classification step, and may further include other steps as necessary.

[0012] The method for separating valuable materials of the present invention is a method for recovering valuable materials from lithium ion secondary batteries (LIBs). Here, the term "valuable materials" refers to materials that can be traded without being discarded, such as various metals such as cobalt (Co), nickel (Ni), iron (Fe), copper (Cu), and aluminum (Al).

[0013] As a result of extensive research, the present inventors have found that, with conventional techniques, when increasing (concentrating) the concentrations of cobalt and nickel to be recovered from a target object such as a lithium-ion secondary battery, the quality and recovery rate of each valuable material may be insufficient.

[0014] More specifically, when processing large LIB packs, such as those used in vehicles, energy storage systems (ESS), uninterruptible power supplies (UPS), and the like, which have become increasingly common in recent years, the inventors have found that in the technology disclosed in Patent Document 1 (Japanese Patent No. 6748274), the pack's exterior components (sometimes referred to as "pack casings" and made mainly of iron) account for a high proportion of the LIB pack weight, and when the LIB packs are crushed and classified, some of the crushed fine iron particles are also recovered in the fine product.The inventors have found that when wet magnetic separation is performed on this fine product containing iron, most of the iron in the crushed material is recovered as magnetic material, and the cobalt and nickel to be separated at this time are also magnetic and are recovered as magnetic material, making it impossible to separate the cobalt and nickel from the iron. The present inventors also found that the non-magnetic matter in wet magnetic separation contained a large amount of sheet-like copper with a large diameter.

[0015] Furthermore, the technology disclosed in Patent Document 2 (Japanese Patent No. 6268130) proposes a sieving step prior to the magnetic separation step, in which copper is separated using a 1.0 mm sieve. However, there is no mention whatsoever of a method for removing iron, which is magnetically attracted together with the cobalt and nickel and cannot be removed in the magnetic separation step.

[0016] Furthermore, in the technology disclosed in Patent Document 3 (Patent No. 6676124), when treating large LIB packs for use in vehicles or ESS / UPS, etc., the volume of the LIB pack is large, and during heat treatment (aimed at deactivating the LIB and burning off the electrolyte), a difference in temperature occurs between the pack surface and the positive electrode active material (including cobalt and nickel) contained in the cells inside the pack (the positive electrode active material is treated at a lower temperature than the pack surface), and the reduction of cobalt and nickel oxides in the positive electrode active material to metal particles and particle growth do not proceed sufficiently compared to when the cells themselves are heat treated. The inventors have found that this makes it difficult to recover the cobalt and nickel particles shown in Patent Document 3 into an intermediate product of 0.3 mm or more (in other words, to recover these fine cobalt and nickel particles, it is necessary to recover them into a fine particle product with a classification point of 300 μm or less).

[0017] As described above, the inventors have found that conventional techniques have problems in that impurities such as iron and copper cannot be sufficiently removed when concentrating and recovering cobalt and nickel from objects such as lithium-ion secondary batteries, and that the recovery rate of cobalt and nickel is low. Therefore, the inventors have conducted extensive research into a method for sorting valuables that can easily separate cobalt and nickel from iron and copper from lithium-ion secondary batteries containing multiple types of valuables, and that can obtain high-quality valuables with increased concentrations of cobalt and nickel at a high recovery rate, and have come up with the present invention. That is, the present inventors have found that a method for sorting valuable materials, which includes a heat treatment step of heat-treating lithium ion secondary batteries containing valuable materials, a crushing step of crushing the heat-treated material obtained in the heat treatment step, and a classification step including a first classification step of classifying the crushed material obtained in the crushing step into a coarse product and an intermediate product at a classification point of 0.6 mm or more and 2.4 mm or less, and a second classification step of classifying the intermediate product into a medium product and a fine product at a classification point of 40 μm or more and 300 μm or less, can easily separate iron, copper, etc. from lithium ion secondary batteries containing multiple types of valuable materials, and can obtain valuable materials in which cobalt and nickel are concentrated at a high recovery rate.

[0018] <Heat Treatment Step> The heat treatment step is a step of heat treating the lithium ion secondary battery containing the valuable material.

[0019] The lithium ion secondary battery is not particularly limited and can be appropriately selected depending on the purpose, but is preferably a lithium ion secondary battery pack selected from those for vehicles, power storage systems, and uninterruptible power supplies.

[0020] In the heat treatment step, for example, aluminum derived from the pack housing of the lithium-ion secondary battery, the constituent members of the module (sometimes referred to as the "module housing"), and the cell case (sometimes referred to as the "cell housing") is separated as a molten material, and organic components derived from the electrolyte are decomposed. More specifically, the heat treatment step is a step in which a lithium-ion secondary battery containing the valuable material is heat-treated to melt the aluminum, the molten material is separated, and a heat-treated product (roasted product) remaining after the molten material is separated is obtained. Here, the heat-treated product means a product obtained by heat-treating a lithium-ion secondary battery.

[0021] The method for carrying out the heat treatment in the heat treatment step is not particularly limited and can be appropriately selected depending on the purpose. For example, a method in which the lithium ion secondary battery is heated in a known roasting furnace can be mentioned.

[0022] The roasting furnace is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include a rotary kiln, a fluidized bed furnace, a tunnel furnace, a batch furnace such as a muffle, a fixed bed furnace, a cupola, and a stoker furnace.

[0023] The atmosphere used for the heat treatment is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include an air atmosphere, an inert atmosphere, a reducing atmosphere, and a low-oxygen atmosphere. An air atmosphere (air atmosphere) refers to an atmosphere containing about 21% by volume of oxygen and about 78% by volume of nitrogen. An example of an inert atmosphere is an atmosphere consisting of nitrogen and / or argon. A reducing atmosphere is, for example, an inert atmosphere such as nitrogen or argon, containing CO, H ２ , H ２ S, SO ２ The low-oxygen atmosphere means an atmosphere containing 11% by volume or less of oxygen.

[0024] The conditions for heat treating (heating) the lithium ion secondary battery (heat treatment conditions) are not particularly limited as long as they allow the lithium ion secondary battery to be separated into its components and to be crushable in the crushing step described below, and can be appropriately selected depending on the purpose. Here, examples of the heat treatment conditions include the heat treatment temperature and the heat treatment time.

[0025] The heat treatment temperature refers to the temperature of the lithium ion secondary battery during the heat treatment. The heat treatment temperature is not particularly limited and can be appropriately selected depending on the form of the lithium ion secondary battery, but is preferably a temperature equal to or higher than the melting point of the casing of the lithium ion secondary battery, or a temperature equal to or higher than the melting point of the positive electrode current collector and lower than the melting point of the negative electrode current collector of the lithium ion secondary battery.

[0026] If the heat treatment temperature is set to a temperature equal to or higher than the melting point of the casing of the lithium-ion secondary battery, the casing can be melted during the heat treatment process if the casing of the lithium-ion secondary battery is made of metal. For example, by placing a tray for collecting the molten metal from the casing under the lithium-ion secondary battery, the metal originating from the casing and the electrodes of the lithium-ion secondary battery can be easily separated and recovered. More specifically, for example, when the casing of the lithium-ion secondary battery contains aluminum, the heat treatment temperature is preferably set to 660°C or higher, which is the melting point of aluminum. This allows the aluminum contained in the casing to be easily separated from other parts of the lithium-ion secondary battery (e.g., electrodes) during the heat treatment process, allowing the aluminum originating from the casing to be easily recovered. Furthermore, at this temperature, cobalt and nickel present as oxides in the positive electrode active material can be reduced to cobalt and nickel metal particles by the action of carbon contained in the negative electrode active material.

[0027] When the heat treatment temperature is set to a temperature above the melting point of the positive electrode current collector and below the melting point of the negative electrode current collector, for example, in a typical configuration in which the positive electrode current collector is aluminum (melting point: 660 ° C) and the negative electrode current collector is copper (melting point: 1,085 ° C), the temperature is preferably 660 ° C or higher and 1,085 ° C or lower, and more preferably 660 ° C or higher and 850 ° C or lower. By doing so, the positive electrode current collector formed of aluminum foil melts and becomes embrittled, making it easier to pulverize in the crushing process described below, allowing the aluminum derived from the housing to be separated and recovered, and the copper contained in the negative electrode current collector can be kept in a shape similar to that of foil without melting. In addition, aluminum can be melted and separated while preventing embrittlement of metals other than aluminum.

[0028] The method for measuring the heat treatment temperature is not particularly limited and can be appropriately selected depending on the purpose. For example, a method for measuring the heat treatment temperature includes inserting a thermometer such as a thermistor into the lithium ion secondary battery at the heat treatment temperature.

[0029] The heat treatment time refers to the time for which the lithium ion secondary battery is subjected to heat treatment. The heat treatment time is not particularly limited and can be appropriately selected depending on the purpose, but is preferably from 1 minute to 5 hours, more preferably from 1 minute to 2 hours, and particularly preferably from 1 minute to 1 hour. The heat treatment time may be, for example, the time required for the lithium ion secondary battery to reach the heat treatment temperature, or the holding time may be short. The heat treatment time of from 1 minute to 5 hours is advantageous in that it can reduce the cost of the heat treatment and improve the efficiency of the heat treatment.

[0030] <<Lithium Ion Secondary Battery>> The lithium ion secondary battery is not particularly limited as long as it can be crushed at least after heat treatment, and can be appropriately selected from known batteries. Specific examples of the lithium ion secondary battery include defective lithium ion secondary batteries generated during the manufacturing process of lithium ion secondary batteries, lithium ion secondary batteries discarded due to defects in the equipment used or the end of the life of the equipment, and used lithium ion secondary batteries discarded due to the end of the life of the equipment. These may be used alone or in combination of two or more.

[0031] The shape, structure, size, and material of the lithium ion secondary battery are not particularly limited and can be appropriately selected depending on the purpose. The shape of the lithium ion secondary battery cell is also not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include laminate type, cylindrical type, button type, coin type, square type, and flat type.

[0032] The form of the lithium ion secondary battery is not particularly limited and can be appropriately selected depending on the purpose. Examples include a battery cell, a battery module, and a battery pack. The battery cell is a unit battery. The battery module refers to a battery in which a plurality of the battery cells are connected and assembled into a single housing (module housing). The battery pack refers to a battery in which a plurality of battery modules are assembled into a single housing (pack housing). The battery pack may also include a controller and a cooling device.

[0033] The lithium ion secondary battery may have a structure including, for example, a positive electrode, a negative electrode, a separator, an electrolyte, and an outer container, but may also have a state in which the positive electrode, the negative electrode, etc., are detached.

[0034] The positive electrode is not particularly limited and can be appropriately selected depending on the purpose as long as it has a positive electrode active material containing either cobalt or nickel, or both. The shape of the positive electrode is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a flat plate shape and a sheet shape.

[0035] --Positive Electrode Current Collector-- The shape, structure, size, and material of the positive electrode current collector are not particularly limited and can be appropriately selected depending on the purpose. Examples of the shape of the positive electrode current collector include foil. Examples of the material of the positive electrode current collector include stainless steel, nickel, aluminum, copper, titanium, and tantalum. Among these, aluminum is preferred.

[0036] The positive electrode material is not particularly limited and can be appropriately selected depending on the purpose. For example, a positive electrode material containing at least a positive electrode active material containing a rare valuable material, and optionally containing a conductive agent and a binder resin, can be used. Examples of the positive electrode active material include lithium cobalt oxide (LiCoO ２ ), lithium cobalt nickel oxide (LiCo １／２ Ni １／２ O ２ ), NCM-based cathode material (LiNi ｘ Co ｙ Mn ｚ O ２ Examples of the conductive agent include (x+y+z=1), NCA-based positive electrode materials (nickel, cobalt, aluminum-based), lithium manganate, and mixtures of these positive electrode materials. The conductive agent is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include carbon black, graphite, carbon fiber, and metal carbides. The binder resin is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include homopolymers or copolymers of vinylidene fluoride, tetrafluoroethylene, acrylonitrile, ethylene oxide, and the like, and styrene-butadiene rubber.

[0037] The negative electrode is not particularly limited and can be appropriately selected depending on the purpose as long as it has a negative electrode active material containing carbon. The shape of the negative electrode is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a flat plate shape and a sheet shape.

[0038] --Negative electrode current collector-- The shape, structure, size, and material of the negative electrode current collector are not particularly limited and can be appropriately selected depending on the purpose. Examples of the shape of the negative electrode current collector include foil. Examples of the material of the negative electrode current collector include stainless steel, nickel, aluminum, copper, titanium, and tantalum. Among these, copper is preferred.

[0039] The negative electrode material is not particularly limited and can be appropriately selected depending on the purpose. Examples include carbon materials such as graphite and hard carbon, and titanates.

[0040] -Electrolyte- The electrolyte is not particularly limited and can be appropriately selected from known electrolytes. For example, the electrolyte contains an electrolyte and an organic solvent, and further contains other components as necessary.

[0041] The cell casing (sometimes referred to as "casing") is not particularly limited and can be appropriately selected depending on the purpose, but is preferably one that can accommodate the positive electrode, the negative electrode, the separator, the electrolyte, etc., and examples thereof include a battery case, etc. The material of the cell casing is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include aluminum, resin (plastic), etc.

[0042] The module housing is not particularly limited and can be selected appropriately depending on the purpose, and examples thereof include a housing that houses multiple battery cells. The material of the cell housing is not particularly limited and can be selected appropriately depending on the purpose, and examples thereof include aluminum, resin (plastic), etc.

[0043] The pack housing is not particularly limited and can be selected appropriately depending on the purpose, and examples thereof include a pack housing that houses multiple battery modules. The material of the cell housing is not particularly limited and can be selected appropriately depending on the purpose, and examples thereof include iron, stainless steel, aluminum, and resin (plastic).

[0044] <Crushing step> The crushing step is a step of crushing the heat-treated product obtained in the heat treatment step. The crushing step is not particularly limited as long as it can crush the heat-treated product to obtain crushed products, and can be appropriately selected depending on the purpose. Here, the crushed products refer to the crushed products obtained by crushing the heat-treated product.

[0045] In the crushing step, the method for crushing the heat-treated product is not particularly limited and can be appropriately selected depending on the purpose, but a method in which the heat-treated product is crushed by impact to obtain crushed products is preferred. For example, when the casing of the lithium ion secondary battery is not melted in the heat treatment step, it is more preferred to pre-crush the heat-treated product by cutting it with a cutter before applying an impact to the heat-treated product.

[0046] Examples of methods for crushing the heat-treated material by impact include a method in which the heat-treated material is thrown by a rotating striking plate and slammed against a collision plate to apply impact, and a method in which the heat-treated material is hit by a rotating striker (beater), and this can be done using, for example, a hammer crusher. Another method for crushing the heat-treated material by impact includes a method in which the heat-treated material is hit by ceramic or other balls, and this method can be done using a ball mill or the like. Furthermore, the crushing of the heat-treated material by impact can also be done using, for example, a biaxial crusher with a short blade width or length that crushes by compression. Another method for crushing the heat-treated material by impact includes a method in which the heat-treated material is hit by two rotating chains to apply impact, and this can be done using, for example, a chain mill.

[0047] The crushing time in the crushing step is not particularly limited and can be appropriately selected depending on the purpose. For example, the crushing time per kg of lithium ion secondary batteries is preferably from 1 second to 30 minutes, more preferably from 2 seconds to 10 minutes, and particularly preferably from 3 seconds to 5 minutes.

[0048] Furthermore, as for the crushing conditions in the crushing step, for example, when crushing with an impact / percussion crusher such as a chain mill or a hammer mill, it is preferable to set the tip speed of the chain or hammer to 10 m / s or more and 300 m / s or less, and the residence time of the lithium ion secondary batteries in the crusher to 1 second or more and 10 minutes or less. By doing so, in the method for sorting valuable resources, it is possible to crush components such as the positive electrode material (e.g., copper, aluminum, etc.) and iron derived from the casing without excessive crushing.

[0049] <Classification step> The classification step includes a first classification step of classifying the crushed material obtained in the crushing step into a coarse-grained product and an intermediate product at a classification point of 0.6 mm or more and 2.4 mm or less, and a second classification step of classifying the intermediate product into a medium-grained product and a fine-grained product at a classification point of 40 μm or more and 300 μm or less.

[0050] The classification step may include a further classification step such as a third classification step in addition to the first classification step and the second classification step, in which case the impurity grade of each product (each element of the valuable material) may be further reduced. Examples of a mode in which a further classification step is performed include a mode in which additional classification is performed at a classification point below the second classification point after the second classification step (third classification step).

[0051] <<First Classification Step>> The first classification step is a step of classifying the crushed material obtained in the crushing step into a coarse product and an intermediate product at a classification point of 0.6 mm to 2.4 mm. By including the first step, the crushed material (intermediate product) from which long pieces of at least one of copper and iron have been removed in advance is processed in the second classification step, thereby obtaining a fine product (valuable material) with higher cobalt and nickel enrichment. The first classification step may be repeated multiple times within the classification point range of the first classification step. This can further reduce the impurity grade of each product (each element of the valuable material).

[0052] The classification point in the first classification step is 0.6 mm or more and 2.4 mm or less, but from the viewpoint of further improving the precision of copper sorting, 1.2 mm is more preferable.

[0053] <<Second Classification Step>> The second classification step is a step of classifying the intermediate product obtained in the first classification step into a medium-sized product and a fine-sized product at a classification point of 40 μm or more and 300 μm or less. Here, the medium-sized product is the coarse-sized product obtained by classifying the intermediate product in the second classification step, and the fine-sized product is the fine-sized product obtained by classifying in the second classification step. The second classification step may be repeated multiple times within the range of the classification point of the second classification step. This can further reduce the impurity quality of each product (each element of the valuable material).

[0054] The classification point in the second classification step is 40 μm or more and 300 μm or less, but is more preferably 40 μm or more and 75 μm or less in terms of being able to remove iron and copper with high efficiency.

[0055] The second classification step preferably includes one or more wet classifications, which can reduce particle aggregation compared to dry classifications and further reduce the impurity content of each product.

[0056] The classification step is not particularly limited as long as it is a processing method that can classify the crushed material within the range of the classification point, and can be appropriately selected depending on the purpose. For example, a multistage vibrating sieve, a cyclone, a cyclosizer, a standard sieve according to JIS Z8801, etc. can be used.

[0057] Here, the "classification point" refers to the sieve opening in the case of sieving, and to the 50% separation diameter in the case of flow classification. In this specification, the "50% separation diameter" refers to the particle size at which the distribution rate to the cyclone underflow for a certain classification particle size is 50%. For example, a cyclone with a classification point of 10 μm refers to a cyclone and its operating conditions that can recover 50% of 10 μm particles in the underflow.

[0058] <Other Steps> The method for sorting valuable resources may include other steps in addition to the heat treatment step, the crushing step, and the classification step. The other steps are not particularly limited and can be appropriately selected depending on the purpose.

[0059]

[0023] <Example of embodiment> Here, an example of an embodiment of the method for sorting lithium ion secondary batteries of the present invention will be described with reference to the drawings. Fig. 1 is a flow chart showing an example of a process flow in one embodiment of the method for sorting valuable resources of the present invention.

[0060] As shown in FIG. 1 , in this embodiment, first, a lithium-ion secondary battery 100 is heat-treated to obtain a heat-treated lithium-ion secondary battery 100. The lithium-ion secondary battery 100 is heat-treated at a temperature equal to or higher than the melting point of aluminum and lower than the melting point of copper (660° C. or higher and 1,085° C. or lower), the aluminum contained in the lithium-ion secondary battery 100 is melted and separated, and molten aluminum 101 is recovered (step ST1 in FIG. 1 ). Next, the heat-treated lithium-ion secondary battery 100 is crushed to obtain crushed material (step ST2 in FIG. 1 ). The crushed material is then classified (first classification step) using a sieve with a mesh size of 0.6 mm to 2.4 mm into a coarse product 102 (oversized material, from which most of the copper and iron have been removed) and an intermediate product 103 (undersized material, from which cobalt and nickel have been recovered) (step ST3 in FIG. 1 ). Next, the intermediate product 103 is classified at a classification point of 40 μm to 300 μm, and is classified into a medium-grain product (coarse grains) 104 and a fine-grain product (fine grains) 105 (second classification step) (step ST4 in FIG. 1 ). Here, some of the copper (Cu) and iron (Fe) recovered in the intermediate product in the first classification step can be separated into the medium-grain product 104, and a fine-grain product with low copper and iron contents and high cobalt and nickel contents can be recovered. In this way, in this embodiment, cobalt, nickel, and manganese contained in the lithium-ion secondary battery can be efficiently separated from iron and copper with high accuracy, and high-quality valuable materials with increased cobalt and nickel concentrations can be obtained at a high recovery rate.

[0061] The present invention will be specifically explained below with reference to examples and comparative examples, but the present invention is not limited to these examples in any way.

[0062] (Example 1) <Heat Treatment Step> A battery pack (approximately 75 kg) of a lithium ion secondary battery including an iron member in the pack housing and aluminum in the cell housing was subjected to heat treatment at a heat treatment temperature of 800°C (heated over 1 hour and then maintained for 2 hours) using a batch burner furnace manufactured by Ecosystem Akita Co., Ltd. as the heat treatment device, to obtain a heat-treated product. When performing the heat treatment, the lithium ion secondary battery was placed on a container and placed in the heat treatment device, and the aluminum was melted and separated and recovered in the lower part of the container (aluminum was melted and recovered).

[0063] <Crushing step> Next, the heat-treated product (heat-treated lithium ion secondary batteries) obtained in the heat treatment step was crushed using a hammer crusher (Makino-type swing hammer crusher HC-20-3.7, manufactured by Makino Sangyo Co., Ltd.) as a crushing device under conditions of 50 Hz (hammer peripheral speed 38 m / sec) and a screen at the outlet portion with grate-type openings of 30 mm x 200 mm, to obtain crushed lithium ion secondary batteries.

[0064] <First Classification Step> Subsequently, the crushed material of the lithium ion secondary batteries was sieved (first classification step) using a sieve (diameter 200 mm, manufactured by Tokyo Screen Co., Ltd.) with mesh openings of 1.2 mm to separate the crushed material into an over-sieve material (coarse product) and an under-sieve material (intermediate product), and 1 kg of the under-sieve product (intermediate product) was used as the crushed material to be used in the next step.

[0065] - Quality Analysis - A portion of the undersize product (intermediate product) obtained in the first classification step was collected, dissolved in aqua regia, and analyzed using an ICP optical emission spectrometer (ICP-AES, iCAP6300, manufactured by Thermo Fisher Scientific K.K.) to determine the quality (mass%) of each element contained in the undersize product (intermediate product). The results are shown in Table 1.

[0066]

[0067] <Second Classification Step> The undersize product (intermediate product) obtained in the <First Classification Step> was treated as the object of the second classification step. Using a 300 μm electromagnetic sieve, the product was classified into an oversize product (medium-sized product) and an undersize product (fine-sized product). The electromagnetic sieve was operated using an electromagnetic sieve shaker (AS200 Control, manufactured by Retsch) at an amplitude of 1.45 mm for 20 minutes.

[0068] - Quality Analysis - Using the same method as in the quality analysis of the intermediate product in the first classification step, the content of each element in the undersize product (fine product) obtained in the second classification step was determined, and the recovery rate (%) of each element in the undersize product (fine product) obtained in the second classification step was determined when the amount of each element in the intermediate product obtained in the first classification step was taken as 100%, and is shown in Table 2.

[0069] (Example 2) Except for changing the classification point of the second classification step to 150 μm, the <heat treatment step>, <crushing step>, <first classification step>, and <second classification step> were performed in the same manner as in Example 1, and a fine product was recovered. Furthermore, the recovery rate of each element in this fine product was determined in the same manner as in Example 1, and the results are shown in Table 2.

[0070] (Example 3) A fine product was recovered by performing the <heat treatment step>, <crushing step>, <first classification step>, and <second classification step> in the same manner as in Example 1, except that the classification point in the second classification step was changed to 75 μm. Furthermore, the recovery rate of each element in this fine product was determined in the same manner as in Example 1, and the results are shown in Table 2.

[0071] (Example 4) A fine product was recovered by carrying out the <heat treatment step>, <crushing step>, <first classification step>, and <second classification step> in the same manner as in Example 1, except that the classification point in the second classification step was changed to 40 μm. Furthermore, the recovery rate of each element in this fine product was determined in the same manner as in Example 1, and the results are shown in Table 2.

[0072] (Example 5) The <heat treatment step>, <crushing step>, and <first classification step> were carried out in the same manner as in Example 1, except that the <second classification step> in Example 1 was changed as follows, and a fine product was recovered. The recovery rates of each element in this fine product were determined in the same manner as in Example 1, and the results are shown in Table 2.

[0073] <Second classification step> 0.1 kg of the intermediate product obtained in the <First classification step> was added to 0.5 L of water in a 1 L glass beaker, and then stirred with a magnetic stirrer at 300 rpm for 1 hour to prepare a slurry of the intermediate product. This slurry was run for 20 minutes using a 40 μm electromagnetic sieve (electromagnetic sieve shaker, AS200 Control, manufactured by Retsch) at an amplitude of 1.45 mm to separate the sieved product (medium-sized product) and the undersieved product (slurry containing fine-sized product), and the slurry containing the fine-sized product was recovered. The obtained slurry containing the fine-sized product was subjected to solid-liquid separation using 5C filter paper, and the cake was dried at 105 ° C. for 2 hours to obtain a fine-sized product.

[0074] Comparative Example 1 A fine product was recovered by carrying out the heat treatment step, crushing step, first classification step, and second classification step in the same manner as in Example 1, except that the classification point in the second classification step was changed to 600 μm. The recovery rates of each element in this fine product were determined in the same manner as in Example 1, and are shown in Table 2.

[0075]

[0076] The results in Table 2 show that in Examples 1 to 5, cobalt and nickel were concentrated in the fine product. That is, cobalt and nickel were obtained in the fine product at a recovery rate of 70% or more, and 70% or more of the iron and 50% or more of the copper contained in the intermediate product were removed from the fine product. In Comparative Example 1, 60% or more of the iron and 80% or more of the copper were recovered in the fine product, and they could not be sufficiently separated from the cobalt and nickel.

[0077] ST1 Heat treatment step ST2 Crushing step ST3 First classification step ST4 Second classification step 100 Lithium ion secondary battery 101 Aluminum 102 Coarse grain product 103 Intermediate product 104 Medium grain product 105 Fine grain product

Claims

DEPCT6720 / 02 / 25671. A method for separating valuable materials, in which the method comprises: a thermal treatment step of performing thermal treatment on a secondary lithium-ion battery containing valuable materials; a compaction step of compacting the thermally treated product obtained in the thermal treatment step; and a classification step, which includes the first classification step of classifying the compacted product obtained in the compaction step into coarse particle products and intermediate products with an inter-sectional cutoff in classification of 0.6 mm or more and 2.4 mm or less, and the second classification step of classifying the intermediate product into medium particle products and fine particle products with an inter-sectional cutoff in classification of 40 µm or more and 300 µm or less.

2. A method for separating valuable materials according to claim 1, in which the compacted product obtained in the compaction step is classified into coarse particle products and intermediate products with an inter-sectional cutoff in classification of 1.2 mm in the first classification step.3.Method of separating valuable materials according to claim 1 or 2, where thermal treatment is performed on lithium-ion secondary batteries at 660°C or higher and 1,085°C or lower in the thermal treatment step; 4. Method of separating valuable materials according to one of claims 1 to 3, where the intermediate products are classified by wet classification at the cut-off point in classification of 40 µm or more and 75 µm or less in the second classification step; 5. Method of separating valuable materials according to one of claims 1 to 4, where the lithium-ion secondary battery is a lithium-ion secondary battery pack selected from lithium-ion secondary battery packs for automobiles, lithium-ion secondary battery packs for energy storage systems, and lithium-ion secondary battery packs for backup power supplies.

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