Method for recovering valuables

Abstract

A method for recovering valuable materials comprises: a heat treatment process for heat treating a target while moving a target receiving means containing a target containing valuable materials, wherein the flame for heat treatment does not come into contact with the target receiving means; and a valuable material recovery process for recovering the valuable materials from the heat-treated target obtained by the heat treatment process.

Description

Technology Field

[0001] The present invention relates to a method for recovering valuable materials. Background Technology

[0002] Lithium-ion rechargeable batteries are lightweight, high-capacity, and high-power rechargeable batteries compared to conventional lead-acid batteries and nickel-cadmium rechargeable batteries, and are used as rechargeable batteries for computers, electric vehicles, and portable devices. For example, in the cathode of a lithium-ion rechargeable battery, valuable materials such as cobalt or nickel are used, such as lithium cobaltate (LiCoO2) and ternary cathode materials (LiNi x Co y Mn z It is used as O2(x+y+z=1)), etc.

[0003] Furthermore, as the use of lithium-ion rechargeable batteries is expected to expand in the future, it is required from the perspective of resource recycling to recover valuable materials such as lithium and copper from batteries that are discarded due to manufacturing defects or the lifespan of the devices and batteries. In this context, when processing lithium-ion rechargeable batteries to recover valuable materials, heat treatment may be performed to neutralize the batteries and render them inactive. It is important to recover the various metals contained in the post-heat-treated material without oxidation (embrittlement) to enhance the value of the recovered valuable materials.

[0004] As a method for heat treatment while preventing embrittlement of various metals included in a lithium-ion secondary battery, for example, a method of treating a lithium-ion battery by heating it is proposed, wherein the lithium-ion battery is heated while preventing the flame from directly contacting the case of the lithium-ion battery by using an incinerator that incinerates the object to be incinerated by flame, and the lithium-ion battery is placed inside a battery protection container that prevents the flame from directly contacting the case of the lithium-ion battery inside the incinerator, and the lithium-ion battery is heated by the flame contacting the outer surface of the battery protection container (for example, see Patent Document 1).

[0005] However, in such conventional technology, there is a problem that, for example, the battery protection container may be deformed or destroyed. Prior art literature

[0006] Japanese Patent Publication No. JP2016-207648 The problem to be solved

[0007] As mentioned above, in the prior art, the lithium-ion secondary battery is heated by exposing the outer surface of a battery protection container that protects the lithium-ion secondary battery to a flame, and as the flame comes into direct contact with the battery protection container, the battery protection container may deteriorate, deform, or be destroyed. Thus, in the prior art, there may be costs involved in manufacturing, replacing, or repairing the battery protection container.

[0008] In addition, in the aforementioned conventional technology, when the battery protection container deteriorates, deforms, or is destroyed, excessive heat is applied to the lithium-ion secondary battery inside the battery protection container, causing valuable materials such as copper recovered from the lithium-ion secondary battery to oxidize or embrittle, which may result in a decrease in the recovery rate and quality of the recovered valuable materials.

[0009] In addition, in the aforementioned conventional technology, a lithium-ion secondary battery is heat-treated using a stationary furnace in the embodiment. However, when continuously heat-treating lithium-ion secondary batteries in a stationary furnace, there is a problem in that, after heat treatment, the next lithium-ion secondary battery cannot be introduced into the furnace unless the furnace interior is lowered to a predetermined temperature (e.g., 200°C or lower) with sufficient heat dissipation time. This is because, when heat-treating lithium-ion secondary batteries using a stationary furnace, if the temperature inside the furnace is high, there is a risk that the lithium-ion secondary battery will ignite immediately after being introduced. Therefore, in the aforementioned conventional technology, lithium-ion secondary batteries cannot be heat-treated continuously, and thus the heat treatment efficiency (productivity) was insufficient.

[0010] The present invention aims to achieve the following objectives by solving the aforementioned problems of the prior art. Specifically, the present invention aims to provide a method for recovering valuable materials that can suppress the deterioration of a means for receiving an object containing valuable materials, and can recover the valuable materials in a high quality with a high recovery rate by efficiently heat-treating the object. means of solving the problem

[0011] The means for solving the above problem are as follows. That is,

[0012] <1> A heat treatment process that uses a continuous furnace to heat-treat an object while moving an object receiving means containing an object containing a valuable material, wherein the flame for heat treatment does not come into contact with the object receiving means, and

[0013] A method for recovering valuable materials, characterized by including a process for recovering valuable materials from a heat-treated object obtained by the above heat treatment process.

[0014] <2> In the above heat treatment process, the above object receiving means being moved is stopped, and the flame is radiated so as not to come into contact with the above object receiving means. <1> Method for recovering valuables as described in

[0015] <3> In the above heat treatment process, when heat-treating a plurality of the above object receiving means, the flame is radiated from between adjacent object receiving means so as not to come into contact with the object receiving means. <1> or <2> Method for recovering valuables as described in

[0016] <4> In the above heat treatment process, the radiation of the flame is weakened while the object receiving means is moving compared to when the object receiving means is stopped. <1> inside <3> A method for recovering valuables as described in any one of them.

[0017] <5> In the above heat treatment process, the ratio of the moving time for moving the object receiving means and the stopping time for stopping the object receiving means satisfies the inequality of the stopping time / the moving time ≥ 10. <2> inside <4> A method for recovering valuables as described in any one of them.

[0018] <6> The object receiving means is formed of iron or stainless steel, the above <1> inside <5> A method for recovering valuables as described in any one of them.

[0019] <7> In the above heat treatment process, the object is heat-treated at a temperature of 750°C or higher and less than 1085°C, the above <1> inside <6> A method for recovering valuables as described in any one of them.

[0020] <8> The above object is a lithium-ion secondary battery, the above <1> inside <7> A method for recovering valuables as described in any one of them.

[0021] <9> The above lithium-ion secondary battery includes a case containing aluminum, and

[0022] In the above heat treatment process, the aluminum of the case in the lithium-ion secondary battery is melted and the molten material is separated. <8> Method for recovering valuables as described in

[0023] <10> The above-mentioned valuable material contains copper, the above <8> or <9> Method for recovering valuables as described in

[0024] <11> In the above heat treatment process, the combustion state of the lithium-ion secondary battery is observed to determine whether the combustion of the lithium-ion secondary battery is completed, and the heat treatment is terminated when it is determined that the combustion of the lithium-ion secondary battery is completed. <8> inside <10> A method for recovering valuables as described in any one of them.

[0025] <12> The above valuable material recovery process comprises a crushing process for crushing the heat-treated material to obtain crushed material, a classification process for classifying the crushed material by a classification point of 0.6 mm or more and 2.4 mm or less to obtain coarse-grained and fine-grained products, and a magnetic separation process for separating the coarse-grained products using a magnet having a magnetic flux density of 0.03 Tesla or more. <1> inside <11> A method for recovering valuables as described in any one of them. Effects of the invention

[0026] According to the present invention, various problems of the prior art can be solved, and the deterioration of a means for receiving an object containing valuable material can be suppressed. Furthermore, a method for recovering valuable material can be provided, which efficiently heat-treats the object to recover the valuable material in a high quality with a high recovery rate. Brief explanation of the drawing

[0027] FIG. 1 is a conceptual diagram showing an example of a continuous furnace that can be used in the method for recovering valuable materials of the present invention. Specific details for implementing the invention

[0028] (Method for recovering valuables)

[0029] The method for recovering valuable materials according to the present invention includes a heat treatment process and a valuable material recovery process, and additionally includes other processes as needed. Accordingly, the valuable material recovery process in the method for recovering valuable materials according to the present invention preferably includes a crushing process, a classification process, and a magnetic separation process, and additionally includes other processes as needed.

[0030] Furthermore, the method for recovering valuable materials according to the present invention is based on the inventors' discovery that in the prior art, when recovering valuable materials such as copper by heat-treating an object such as a lithium-ion battery (LIB), the means for receiving the object, such as a container, may deteriorate. Additionally, the method for recovering valuable materials according to the present invention is based on the inventors' discovery that in the prior art, the object cannot be heat-treated efficiently, and the quality or recovery rate of the recovered valuable materials may not be sufficient.

[0031] More specifically, as mentioned above, in the prior art, heat treatment is performed by directly exposing a flame to a battery protection container that protects a lithium-ion secondary battery, which can cause the battery protection container to deteriorate, deform, or break. Therefore, in the prior art, costs may be incurred for the manufacture, replacement, and repair of the battery protection container. Furthermore, when the battery protection container deteriorates, deforms, or is damaged, valuable materials such as copper recovered from the lithium-ion secondary battery may oxidize or embrittle, resulting in a decrease in the recovery rate or quality of the recovered materials. In addition, in the embodiments of the prior art mentioned above, the lithium-ion secondary battery is heat-treated using a stationary furnace, and since the lithium-ion secondary battery cannot be heat-treated continuously, the efficiency (productivity) of the heat treatment was insufficient.

[0032] As such, the inventors have recognized the problem that in the prior art, the means for receiving an object containing valuable material deteriorates, resulting in insufficient efficiency when heat-treating the object, and furthermore, the object cannot be heat-treated efficiently, and there are cases where the quality or recovery rate of the recovered valuable material is insufficient.

[0033] Thus, the inventors have arrived at the present invention by repeatedly examining a method for recovering valuable materials that can suppress the deterioration of a means for receiving an object containing valuable materials and efficiently heat-treat the object to recover the valuable materials in high quality with a high recovery rate.

[0034] That is, the inventors have discovered that by a method for recovering valuable materials comprising a heat treatment process in which a continuous furnace is used to heat-treat a target while moving a target receiving means containing a target containing valuable materials, such that a flame for heat treatment does not come into contact with the target receiving means, and a valuable material recovery process for recovering valuable materials from a heat-treated target obtained by the heat treatment process, the deterioration of a target receiving means containing valuable materials can be suppressed, and the target can be heat-treated efficiently to recover valuable materials in a high quality with a high recovery rate.

[0035] Accordingly, in the method for recovering valuable materials according to the present invention, a continuous furnace is used to heat-treat a target while moving a target receiving means in which a target containing valuable materials is received, so that the flame for heat treatment does not come into contact with the target receiving means (heat treatment process).

[0036] In this way, the present invention heat-treats an object using a continuous furnace while moving an object receiving means. Therefore, in the present invention, by continuously placing a plurality of object receiving means into the continuous furnace, the object received in the object receiving means can be heat-treated continuously, thereby allowing the object to be heat-treated more efficiently. That is, the number of objects that can be heat-treated per unit time can be increased.

[0037] Furthermore, in the present invention, as described above, the object is heat-treated by ensuring that the flame for heat treatment does not come into contact with the object receiving means. Thus, in the present invention, it is possible to prevent the object receiving means from being overheated, thereby suppressing the deterioration of the object receiving means. In addition, since the deterioration of the object receiving means can be suppressed in the present invention, maintenance costs such as replacement and repair of the object receiving means can be reduced.

[0038] In addition, in the method for recovering valuable materials according to the present invention, the flame for heat treatment is prevented from coming into contact with the means for receiving the object, thereby suppressing the deterioration of the means for receiving the object. Thus, oxidation and embrittlement of valuable materials (e.g., copper, etc.) contained in the object, which occur when, for example, the means for receiving the object is damaged and the heat treatment flame comes into direct contact with the object, can be suppressed, and the valuable materials can be recovered in high quality with a high recovery rate in the valuable material recovery process.

[0039] As such, the method for recovering valuable materials according to the present invention includes the aforementioned heat treatment process and the valuable material recovery process, thereby suppressing the deterioration of the object receiving means that receives the object containing the valuable material, and efficiently heat-treating the object, allowing the valuable material to be recovered in high quality with a high recovery rate.

[0040] Below, each process and the like in the method for recovering valuable materials according to the present invention will be described in detail.

[0041] <Heat Treatment Process>

[0042] The heat treatment process is a process of heat treating an object by using a continuous furnace while moving an object receiving means containing an object containing a valuable material, such that the flame for heat treatment does not come into contact with the object receiving means. In other words, the heat treatment process is, for example, a process of obtaining a heat-treated object by heat treating an object by a continuous furnace by radiating a flame such that the flame does not come into direct contact with the object receiving means containing the object. Meanwhile, the term "heat-treated object" means that the object is obtained by heat treating it.

[0043] <<Objects · Valuables>>

[0044] As for the object, there are no particular restrictions as long as it contains valuable materials and can be heat-treated by a continuous furnace while contained in an object receiving means, and it can be appropriately selected according to the purpose. Examples of objects include secondary batteries such as lithium-ion batteries and nickel-hydrogen batteries. Typically, it is preferable to use lithium-ion batteries.

[0045] Here, the term "valuable material" means a material that can be traded without being discarded, and examples include various metals. When the subject is a lithium-ion secondary battery, valuable materials include, for example, high-grade carbon (C) concentrate, copper (Cu), aluminum (Al), lithium (Li), cobalt (Co), nickel (Ni), etc. Meanwhile, high-grade carbon (C) concentrate (for example, a grade of 80% or more) can be appropriately used as needed, for example, as a reducing agent during metal smelting.

[0046] -Lithium-ion secondary battery-

[0047] In the present invention, there are no particular limitations on the lithium-ion secondary battery, and it can be appropriately selected according to the purpose. Examples include defective lithium-ion secondary batteries generated during the manufacturing process, lithium-ion secondary batteries discarded due to device defects or the lifespan of the device, and used lithium-ion secondary batteries discarded according to their lifespan.

[0048] There are no specific restrictions on the shape, structure, size, or material of lithium-ion secondary batteries, and they can be appropriately selected depending on the purpose.

[0049] There are no particular restrictions on the shape of lithium-ion secondary batteries, and they can be appropriately selected depending on the purpose; examples include laminate type, cylindrical type, button type, coin type, prismatic type, and flat type.

[0050] In addition, there are no specific restrictions on the form of the lithium-ion secondary battery, and it can be appropriately selected according to the purpose, such as battery cells, battery modules, and battery packs. Here, a battery module refers to a combination of multiple battery cells, which are unit cells, connected and assembled in a single case, and a battery pack refers to a combination of multiple battery modules assembled in a single case. Furthermore, a battery pack may be equipped with a control controller, a cooling device, etc.

[0051] Examples of lithium-ion secondary batteries include those equipped with a positive electrode, a negative electrode, a separator, an electrolyte containing an organic solvent, and an external container which is a battery case accommodating the positive electrode, negative electrode, separator, and electrolyte. Meanwhile, the lithium-ion secondary battery may be in a state where the positive electrode or negative electrode is detached.

[0052] --anode-

[0053] As for the anode, there are no particular restrictions and it can be appropriately selected according to the purpose. It is preferable to have an anode current collector and an anode material containing one or more of cobalt and nickel. As for the shape of the anode, there are no particular restrictions and it can be appropriately selected according to the purpose. Examples include a flat plate shape, a sheet shape, etc.

[0054] --Bipolar collector-

[0055] As for the positive current collector, there are no specific restrictions on its shape, structure, size, material, etc., and it can be appropriately selected according to the purpose.

[0056] Examples of shapes for the positive current collector include foil-shaped types.

[0057] Examples of materials for the anode current collector include stainless steel, nickel, aluminum, copper, titanium, and tantalum. Among these, aluminum is preferred.

[0058] There are no particular restrictions on the cathode material, and it can be appropriately selected according to the purpose. For example, a cathode material may include at least a lithium-containing cathode active material, and if necessary, a conductive agent and a binding resin.

[0059] There are no particular restrictions on the cathode active material, and it can be appropriately selected depending on the purpose; however, it is preferable to include one or more of cobalt and nickel.

[0060] As cathode active materials, for example, lithium manganate (LiMn2O4) called the LMO system, lithium cobaltate (LiCoO2) called the LCO system, and LiNi called the ternary or NCM system. x Co y Mn z O2(x+y+z=1), LiNi called the NCA system x Co y Al z (x+y+z=1), lithium iron phosphate (LiFePO4), lithium cobalt nickelate (LiCo 1 / 2 Ni1 / 2 Examples include lithium oxide (O2) and lithium titanate (Li2TiO3). Additionally, a combination of these materials can be used as the cathode active material.

[0061] There are no specific restrictions on the conductive agent, and it can be appropriately selected depending on the purpose; examples include carbon black, graphite, carbon fiber, and metal carbides.

[0062] There are no particular restrictions on the binding resin, and it can be appropriately selected according to the purpose. Examples include homopolymers or copolymers such as vinylidene fluoride, tetrafluoroethylene, acrylonitrile, and ethylene oxide, as well as styrene-butadiene rubber.

[0063] --cathode-

[0064] As for the cathode, there are no particular restrictions and it can be appropriately selected according to the purpose, but it is preferable to have a cathode active material containing carbon (C) and a cathode current collector.

[0065] There are no particular restrictions on the shape of the cathode, and it can be appropriately selected according to the purpose; for example, flat plate type, sheet type, etc.

[0066] --Cathode Current Collector--

[0067] As for the cathode current collector, there are no particular restrictions on its shape, structure, size, material, etc., and it can be appropriately selected according to the purpose.

[0068] Examples of shapes for the negative current collector include thin types.

[0069] Examples of materials for the cathode current collector include stainless steel, nickel, aluminum, copper, titanium, tantalum, etc. Among these, copper is preferred.

[0070] As for the negative electrode active material, there are no particular restrictions as long as it contains carbon (C), and it can be appropriately selected according to the purpose; examples include carbon materials such as graphite and hard carbon, titanate, and silicon. In addition, these materials may be used in combination as the negative electrode active material.

[0071] In addition, there are no specific restrictions on the material of the outer container (case) of the lithium-ion secondary battery, and it can be appropriately selected depending on the purpose; for example, aluminum, iron, stainless steel, resin (plastic), etc.

[0072] In the present invention, even when the target object is a lithium-ion secondary battery containing a large amount of aluminum, such as a lithium-ion secondary battery having an aluminum case, the aluminum, which is an example of a valuable material, can be separated as a molten material by melting it in a heat treatment process. In other words, the method for recovering valuable materials according to the present invention is preferably such that the lithium-ion secondary battery is equipped with a case containing aluminum, and the aluminum in the case of the lithium-ion secondary battery is melted in a heat treatment process to separate the molten material.

[0073] Means of receiving the object

[0074] As for the means for receiving the object, there are no particular restrictions as long as it can receive the object and be placed in a continuous furnace, and it can be appropriately selected according to the purpose, for example, containers, drums, and external containers for lithium-ion secondary battery packs or modules.

[0075] For the material of the object receiving means, it is preferable that the melting point be higher than the temperature during heat treatment in a continuous furnace (heat treatment temperature). More specifically, for the material of the object receiving means, iron, stainless steel, etc. are preferable. In other words, in the method for recovering valuable materials according to the present invention, it is preferable that the object receiving means be formed of iron or stainless steel. By doing so, deterioration, deformation, and breakage of the object receiving means during heat treatment can be further suppressed.

[0076] Regarding the size of the object receiving means, there are no specific restrictions as long as it can accommodate the object and be placed in a continuous furnace, and it can be appropriately selected according to the purpose. For example, it is desirable to make it sized so that it can be mounted on a cart of a continuous furnace, and it is desirable to make it sized so that adjacent object receiving means do not come into contact when mounted on each cart, that is, so that there is a gap between the object receiving means.

[0077] As for the shape and structure of the means for receiving the object, there are no particular restrictions as long as it is capable of receiving the object, and it can be appropriately selected according to the purpose.

[0078] Here, it is preferable that the object receiving means be provided with an opening through which gas can be circulated. In this case, it is preferable that the object receiving means accommodate a lithium-ion secondary battery so that gas cannot be circulated in parts other than the opening. By providing the opening, the pressure or atmosphere inside the object receiving means can be controlled.

[0079] There are no particular restrictions on the shape of the opening, and it can be appropriately selected according to the purpose. Furthermore, regarding the location of the opening in the object receiving means, there are no particular restrictions as long as it is a location where gas can be circulated during heat treatment, and it can be appropriately selected according to the purpose. Meanwhile, multiple openings may be provided in the object receiving means.

[0080] In addition, a hole provided in the outer casing of a lithium-ion secondary battery pack or module may be used as the opening. A lithium-ion secondary battery pack is generally provided with a hole for connecting a charging or discharging cable or plug to a conductive part inside the pack or module, and this can be utilized as the opening.

[0081] There are no specific restrictions on the size (area) of the opening, and it can be appropriately selected according to the purpose. It is preferable that the opening be 12.5% ​​or less of the surface area of ​​the object receiving means, and more preferable that it be 6.3% or less. By making the size of the opening 12.5% ​​or less of the surface area of ​​the object receiving means, oxidation of valuable materials contained in the current collector during heat treatment can be suppressed. In the following, the area of ​​the opening relative to the surface area of ​​the object receiving means may be referred to as the "opening ratio." Meanwhile, if the object receiving means is provided with multiple openings, the opening ratio may be the sum of the areas of each opening relative to the surface area of ​​the object receiving means.

[0082] If the opening ratio in the object receiving means is within the above-mentioned desirable range, for example, when the atmosphere outside the object receiving means is an atmospheric atmosphere, the atmosphere inside the object receiving means during heat treatment can be made a low-oxygen atmosphere.

[0083] Here, as a means for receiving an object, it is preferable to have a cover portion that can be opened and closed to receive a lithium-ion secondary battery. By doing so, a lithium-ion secondary battery can be easily received in the means for receiving an object, and also, after a heat treatment process, the heat-treated lithium-ion secondary battery (heat-treated object) can be easily removed.

[0084] There are no particular restrictions on the cover part, and it can be appropriately selected according to the purpose.

[0085] In addition, the cover portion may be fixed so that it can be opened and closed by means of, for example, a hinge, or it may be opened and closed by removing the cover portion.

[0086] <Continuous Furnace>

[0087] As long as the continuous furnace used in the heat treatment process allows the workpiece to be heat-treated while moving the workpiece receiving means containing the workpiece, without the flame for heat treatment coming into contact with the workpiece receiving means, there are no particular restrictions, and it can be appropriately selected according to the purpose. Examples of continuous furnaces (tunnel furnaces) include, for instance, a pusher-type continuous furnace.

[0088] Here, for example, if a lithium-ion secondary battery is to be processed continuously by a batch furnace, the next lithium-ion secondary battery to be processed cannot be introduced into the furnace until the heat treatment of the lithium-ion secondary battery is completed and the heat dissipation within the furnace is completed. However, by using a continuous furnace (tunnel furnace), the heat dissipation of the lithium-ion secondary battery that was heat-treated first and the heat treatment of the lithium-ion secondary battery to be processed next can be carried out continuously and efficiently by providing a heat dissipation area after the heat treatment area.

[0089] Here, the flame for heat treatment can be emitted, for example, by a flame emitting means provided in a continuous furnace. There are no particular restrictions on the flame emitting means, and they can be appropriately selected according to the purpose; for example, a burner may be used.

[0090] In addition, as an example of a flame-emitting means, it is desirable that the air ratio in the burner (the ratio of the actual air volume to the theoretical air volume) be 2 or less. By making the air ratio in the burner 2 or less, overheating of the space around the burner and deterioration of the object receiving means due to the air supplied from the burner can be further suppressed.

[0091] For example, when performing a heat treatment process, it is desirable that the continuous furnace be able to stop the object receiving means that was moving and emit a flame so that the flame does not come into contact with the object receiving means. In other words, in the present invention, it is desirable to stop the object receiving means that was moving during the heat treatment process and emit a flame so that the flame does not come into contact with the object receiving means. By doing so, the flame coming into contact with the object receiving means can be prevented more reliably.

[0092] More specifically, it is desirable to reduce the flame radiation while the object receiving means is moving during the heat treatment process compared to when the object receiving means is stopped. By doing so, it is possible to more reliably prevent the flame from coming into contact with the object receiving means.

[0093] When the flame emission is weakened while the object receiving means is moving compared to when the object receiving means is stopped, the flame emission output may be weakened (reduced) or the flame emission may be stopped.

[0094] In addition, it is desirable that the continuous furnace be able to emit a flame from between adjacent object receiving means when heat-treating, for example, a plurality of object receiving means. In other words, in the present invention, it is desirable to emit a flame from between adjacent object receiving means so as not to come into contact with the object receiving means when heat-treating a plurality of object receiving means. By doing so, it is possible to more reliably prevent the flame from coming into contact with the object receiving means when heat-treating a plurality of object receiving means.

[0095] Here, for a continuous furnace capable of emitting a flame from between adjacent object receiving means, for example, when heating after stopping the object receiving means, a flame emitting means may be used in which a flame emitting means is positioned at a point located between adjacent object receiving means.

[0096] Here, FIG. 1 is a conceptual diagram showing an example of a continuous furnace that can be used in the method for recovering valuable materials of the present invention.

[0097] In the example shown in FIG. 1, the continuous furnace is equipped with a heating waiting room (11), a heating section (12), a holding section (13), and a cooling waiting room (14). Between the heating waiting room (11) and the heating section (12), and between the cooling waiting room (14) and the holding section (13), a movable door (15) that can be opened and closed by hydraulic pressure or the like is provided. In addition, in the continuous furnace shown in FIG. 1, a secondary combustion furnace (19) is connected to a smoke passage (20) above the holding section (13) as an exhaust gas treatment means. Meanwhile, FIG. 1 is a conceptual diagram of the interior of the continuous furnace when viewed from the horizontal direction.

[0098] In the example shown in FIG. 1, a means for receiving an object (17) containing an object is mounted on each of the ten carts (16), and the carts (16) and the means for receiving an object (17) move sequentially from the heating waiting room (11) toward the heating section (12) in the direction indicated by the arrow. Additionally, when moving the carts (16) and the means for receiving an object (17), for example, by pressing the cart (16) located at the left end of the heating section (12) in the direction of the arrow, the carts (16) come into contact with each other and push each cart (16) to move. Meanwhile, in the example shown in FIG. 1, while the carts (16) and the means for receiving an object (17) are moving, the radiation of the flame (18) is made weaker than when the carts (16) and the means for receiving an object (17) are stopped.

[0099] At this time, in the heating unit (12), flames (18) are emitted by a flame emitting means so as not to touch the object receiving means (17), and the object received in the object receiving means (17) is heat-treated by the flames (18). More specifically, as shown in the example in FIG. 1, when heating with the object receiving means (17) stopped, a flame emitting means is positioned at a point located between adjacent object receiving means (17), and flames (18) are emitted between the adjacent object receiving means (17). Meanwhile, in the example shown in FIG. 1, flames (18) are emitted from both the left and right sides in the direction of travel (indicated by arrows) of the cart (16) and the object receiving means (17) in the continuous furnace. Thus, in the example shown in FIG. 1, flames (18) are emitted in a direction toward the side of the object receiving means (17) so as not to touch the object receiving means (17).

[0100] In addition, in the example shown in FIG. 1, a flame (18) necessary to maintain the temperature inside the furnace is radiated from the maintenance part (13). Then, the cart (16) and the object receiving means (17) are moved to the cooling waiting room (14) and cooled.

[0101] As described above, when heat-treating an object by repeatedly stopping the emission of a flame and moving the object receiving means, and then emitting a flame without touching the object receiving means to heat it, there are no particular restrictions on the ratio of the movement time for moving the object receiving means to the stopping time for stopping the object receiving means, as long as the object can be sufficiently heat-treated, and the ratio can be appropriately selected according to the purpose. Regarding the ratio of the movement time for moving the object receiving means to the stopping time for stopping the object receiving means, for example, it is desirable to satisfy the inequality stopping time / movement time ≥ 10.

[0102] Since the ratio of stop time to travel time in the heat treatment process satisfies the above inequality, the travel time can be shortened relative to the stop time, thereby suppressing the temperature drop inside the continuous furnace during heat treatment and allowing for more efficient heat treatment.

[0103] In addition, the flame emission time per instance of stopping the object receiving means and emitting the flame is preferably 5 minutes or more and 3 hours or less.

[0104] By setting the flame blasting time to 5 minutes or more and 3 hours or less, it is possible to prevent insufficient heat treatment of the target object (e.g., lithium-ion secondary battery) and to suppress embrittlement of the recovered valuable material while reducing the amount of fuel required for heat treatment.

[0105] In the present invention, when the object is a lithium-ion secondary battery, it is preferable to observe the combustion state of the lithium-ion secondary battery during the heat treatment process to determine whether the combustion of the lithium-ion secondary battery is complete, and to terminate the heat treatment when it is determined that the combustion of the lithium-ion secondary battery is complete. By doing so, the lithium-ion secondary battery can be heat-treated without excess or deficiency, and the deterioration of the object receiving means can be further suppressed, thereby allowing the heat treatment to be performed more efficiently in a short period of time.

[0106] There are no particular restrictions on the methods for observing the combustion state of lithium-ion secondary batteries, and they can be appropriately selected depending on the purpose. Examples include the analysis of images acquired by visual inspection or cameras, the analysis of temperature information acquired by thermography, thermocouples, or radiation thermometers, and the analysis of gas (CO, CO2, O2, etc.) concentration fluctuations. Furthermore, these methods may be used in combination.

[0107] More specifically, for example, by confirming from an image of a camera installed inside the furnace that ignition from the object receiving means has ceased, and by opening the furnace inlet to the extent that gas inside the furnace does not leak out of the system and visually confirming from outside the furnace that ignition from the object receiving means has ceased, it is possible to determine whether the combustion of the lithium-ion secondary battery has been completed.

[0108] In addition, when the heat treatment is terminated when it is determined that the combustion of the lithium-ion secondary battery is complete, for example, the flame inside the furnace of the continuous furnace may be completely stopped, or the flame necessary to maintain the temperature inside the furnace of the continuous furnace may be radiated so as not to come into contact with the means for receiving the object.

[0109] <<Heat Treatment Conditions>>

[0110] As for the conditions for heat-treating (heating) the object (heat treatment conditions), there are no particular restrictions as long as they are conditions that allow each component of the object to be in a state where valuable materials can be recovered in the valuable material recovery process described later, and they can be appropriately selected according to the purpose.

[0111] Here, heat treatment conditions include, for example, heat treatment temperature, heat treatment time, atmosphere, etc.

[0112] The term "heat treatment temperature" refers to the temperature of an object (e.g., a lithium-ion secondary battery) during heat treatment. The heat treatment temperature can be measured by inserting a thermometer, such as a coupler or a thermistor, into the object during heat treatment.

[0113] The heat treatment temperature can be appropriately selected depending on the object.

[0114] Here, when the object is a lithium-ion secondary battery, the heat treatment temperature is preferably higher than the melting point of the case (outer container) of the lithium-ion secondary battery. By doing so, in cases where the case of the lithium-ion secondary battery is formed of metal, the case is melted during the heat treatment process, and by placing a support member to recover the molten metal of the case, for example, below the lithium-ion secondary battery, the metal derived from the case and the electrode of the lithium-ion secondary battery can be easily separated and recovered.

[0115] More specifically, for example, when the case of a lithium-ion secondary battery contains aluminum, it is preferable to set the heat treatment temperature to 660°C or higher, which is the melting point of aluminum. By doing so, the aluminum contained in the case of the lithium-ion secondary battery can be melted and recovered during the heat treatment process. That is, in the method for recovering valuable materials according to the present invention, when a lithium-ion secondary battery having a case containing aluminum is used as the target, the lithium-ion secondary battery is heat-treated at 660°C or higher during the heat treatment process, thereby easily separating the aluminum contained in the case from other parts of the lithium-ion secondary battery (e.g., electrodes, etc.) and easily recovering the aluminum derived from the case.

[0116] When recovering aluminum from the case of a lithium-ion secondary battery, for example, aluminum can be recovered in a heat treatment process by placing an aluminum support on a cart in a continuous furnace. In addition, since aluminum has low viscosity, when the cart moves, the aluminum contained within the object receiving means shakes within the object receiving means and falls onto the support, thereby further improving the aluminum recovery rate.

[0117] In addition, in the method for recovering valuable materials according to the present invention, when the target object is a lithium-ion secondary battery, the heat treatment temperature is preferably 750°C or higher, more preferably 750°C or higher and 1080°C or lower, and particularly more preferably 750°C or higher and 900°C or lower.

[0118] By setting the heat treatment temperature to 750°C or higher, the Li(Ni / Co / Mn) in the cathode active material of the lithium-ion secondary battery and the lithium in the LiPF6 electrolyte can be converted into substances soluble in aqueous solutions, such as lithium fluoride (LiF), lithium carbonate (Li2CO3), and lithium oxide (Li2O), and can be separated from impurities other than fluorine during lithium leaching. Furthermore, by setting the heat treatment temperature to 750°C or higher, the cobalt oxide and nickel oxide contained in the cathode active material are reduced to metals, and these metals can be grown to a particle diameter that is easily magnetically attached during the magnetic separation process described later. Additionally, the growth of the metal particle diameter is more likely to occur when heat treatment is performed at a higher temperature.

[0119] In addition, by setting the heat treatment temperature to 750°C (a temperature higher than the melting point of aluminum, 660°C) or higher and less than 1085°C (the melting point of copper), for example, when a lithium-ion secondary battery having a case containing aluminum is used as the target, aluminum derived from the case can be separated and recovered, and the oxidation or embrittlement of copper contained in the negative electrode current collector can be further suppressed, thereby further improving the recovery rate and quality of copper.

[0120] There are no specific restrictions on the heat treatment time (the time for performing heat treatment on the object) and it can be appropriately selected according to the purpose; for example, it is preferable to have a time of 1 minute or more and 10 hours or less, more preferable to have a time of 1 minute or more and 5 hours or less, and particularly more preferable to have a time of 1 minute or more and 3 hours or less. The heat treatment time may be, for example, the time until the object reaches the heat treatment temperature, and the holding time may be short. Having a heat treatment time of 1 minute or more and 5 hours or less is advantageous in that it can suppress the cost of heat treatment and improve the efficiency of heat treatment.

[0121] There are no particular restrictions on the atmosphere used for heat treatment, and it can be appropriately selected according to the purpose; for example, an air atmosphere, an inert atmosphere, a reducing atmosphere, a low-oxygen atmosphere, etc.

[0122] Atmospheric atmosphere refers to an atmosphere created using air.

[0123] An inert atmosphere can be exemplified by an atmosphere composed of nitrogen or argon.

[0124] A reducing atmosphere means an atmosphere containing CO, H2, H2S, SO2, etc., in an inert atmosphere such as nitrogen or argon, for example.

[0125] A low-carbon atmosphere means an atmosphere in which the partial pressure of oxygen is 11% or less.

[0126] Among these, a low-carbon atmosphere is desirable in that it can reduce the oxidation of the object receiving means and valuable materials such as copper by oxygen, and can also be achieved by controlling the oxygen supply amount of the burner without requiring special atmosphere adjustment.

[0127] <Valuable Material Recovery Process>

[0128] The valuable material recovery process is a process for recovering valuable materials from the heat-treated material of an object obtained by a heat treatment process.

[0129] As for the valuable material recovery process, there are no particular restrictions as long as valuable materials can be recovered from the heat-treated material, and it can be appropriately selected according to the purpose; as mentioned above, it is desirable to include a crushing process, a classification process, and a magnetic separation process.

[0130] <<Crushing Process>>

[0131] The crushing process is a process of crushing heat-treated materials to obtain crushed material.

[0132] As for the crushing process, there are no particular restrictions as long as it is a process of crushing a heat-treated material (roasted material) to obtain a crushed material, and it can be appropriately selected according to the purpose. Also, the term "crushed material" refers to a heat-treated material that has been crushed.

[0133] For the crushing process, for example, a process in which a crushed material is obtained by crushing the heat-treated material by impact is preferred. For example, when selecting a lithium-ion secondary battery as the target material, if the case of the lithium-ion secondary battery is not to be melted during the heat treatment process, it is more preferable to perform preliminary crushing by cutting the heat-treated material with a cutter before applying impact to it.

[0134] Methods of crushing by impact include, for example, a method of throwing the heat-treated material with a rotating impact plate to strike a collision plate, or a method of striking the heat-treated material with a rotating beater; this can be carried out, for example, by a hammer crusher. Additionally, a method of crushing by impact may involve, for example, striking the heat-treated material with a ball made of ceramic or the like, and this method can be carried out by a ball mill. Furthermore, crushing by impact can be carried out, for example, by using a twin-axis crusher with a short blade width and blade length that performs crushing by compression.

[0135] In addition, as a method of crushing by impact, for example, a method of striking the heat-treated workpiece with two rotating chains can be cited, and this can be carried out by, for example, a chain mill.

[0136] Here, by crushing the heat-treated material of the lithium-ion secondary battery through impact, the crushing of the positive current collector (e.g., aluminum (Al)) is promoted, while the negative current collector (e.g., copper (Cu)), whose shape has not changed significantly, exists in a form such as a foil. Thus, in the crushing process, the negative current collector is only cut to the extent that a crushed material can be obtained in a state in which valuable materials originating from the positive current collector (e.g., aluminum) and valuable materials originating from the negative current collector (e.g., copper (Cu)) can be efficiently separated in the classification process described later.

[0137] There are no specific limitations on the crushing time in the crushing process, so it can be appropriately selected depending on the purpose, but for example, when the object is a lithium-ion secondary battery, the crushing time per 1 kg of lithium-ion secondary battery is preferably 1 second or more and 30 minutes or less, more preferably 2 seconds or more and 10 minutes or less, and particularly more preferably 3 seconds or more and 5 minutes or less.

[0138] In addition, regarding the crushing conditions in the crushing process, for example, when crushing with an impact or blowing crusher such as a chain mill or a hammer mill, it is preferable to set the leading speed of the chain or hammer to 10 m / sec or more and 300 m / sec or less, and the residence time of the object inside the crusher to 1 second or more and 10 minutes or less. By doing so, the method for recovering valuable materials according to the present invention can crush components such as copper or aluminum, which are cathode materials, and Fe derived from the case, without excessive crushing.

[0139] <<Classification Process>>

[0140] The classification process is a process of obtaining coarse and fine products by classifying crushed material into classification points of 0.6 mm or more and 2.4 mm or less.

[0141] As for the classification process, there are no particular restrictions, and it can be appropriately selected according to the purpose, as long as it is a process that can obtain coarse and fine products by classifying the crushed material by a classification point of 0.6 mm or more and 2.4 mm or less. By performing the classification process, when the target material is a lithium-ion secondary battery, for example, copper (Cu), iron (Fe), aluminum (Al), etc. can be separated as coarse products, and lithium (Li), cobalt (Co), nickel (Ni), manganese (Mn), carbon (C), etc. can be separated as fine products.

[0142] The classification process can be carried out using, for example, a vibrating sieve, a multi-stage vibrating sieve, a cyclone, a standard sieve of JIS Z8801, etc.

[0143] As for the particle size of the classification (classification point, sieve mesh size), it is preferable to have a size of 0.6 mm or more and 2.4 mm or less, more preferable to have a size of 0.85 mm or more and 1.7 mm or less, and particularly more preferable to have a size of about 1.2 mm.

[0144] By making the particle size of the classification 2.4 mm or less, the incorporation of copper (Cu), iron (Fe), aluminum (Al), etc. into the fine product can be suppressed, and by making the particle size of the classification 0.6 mm or more, the incorporation of carbon (C), lithium (Li), cobalt (Co), nickel (Ni), manganese (Mn), etc. into the coarse product can be suppressed.

[0145] In addition, the classification of materials that did not pass through the sieve (coarse product) and materials that passed through the sieve (fine product) can be repeated multiple times. By sieving again in this way, the impurity grade of each product can be further reduced.

[0146] Meanwhile, the crushing process and the classification process may be carried out simultaneously. For example, the crushing process and the classification process may be performed as a crushing and classification process (crushing and classification) in which the heat-treated material obtained from the heat treatment process is crushed and the crushed material is classified into coarse and fine products.

[0147] <<Magnetic Separation Process>>

[0148] The magnetic separation process is a process of separating assembly products using a magnet having a magnetic flux density of 0.03 Tesla or higher. In other words, in the magnetic separation process, valuable materials are recovered from the target material (the crushed material obtained by heat-treating and crushing the target material) by performing separation by magnetic force on the crushed material. Meanwhile, in the following, separation by magnetic force may be referred to as "magnetic separation."

[0149] The magnetic separation process can be carried out using a known magnetic separator, etc.

[0150] There are no particular limitations on the magnetic separator that can be used in the present invention, and it can be appropriately selected according to the purpose. Examples include bar magnets, grid magnets, rotary magnets, magnet strainers, high magnetic pulley (magnet pulley) magnetic separators, drum-type magnetic separators, ceiling-mounted magnetic separators, etc. Among these, it is preferable to use a drum-type magnetic separator or a ceiling-mounted magnetic separator in the present invention.

[0151] In the magnetic separation process, separation is performed by magnetic force capable of separating magnetic materials and non-magnetic materials contained in the object according to, for example, the type of object (the type of valuable material contained in the object).

[0152] Here, the term "attractive material" refers to a material that can be attracted toward a magnetic source by generating an attractive force between itself and the source due to the magnetic force generated by the source (e.g., a magnet, an electromagnet, etc.) that generates a magnetic force (magnetic field). Examples of attractive materials include ferromagnetic metals. Examples of ferromagnetic metals include iron, nickel, cobalt, etc.

[0153] The term "non-magnetic material" means that it is not attracted toward the magnetic source by the magnetic force generated by the above-mentioned magnetic source. There are no particular restrictions on the non-magnetic material, and it can be selected according to the purpose. In addition, examples of metallic non-magnetic materials include paramagnetic or diamagnetic metals. Examples of paramagnetic or diamagnetic metals include aluminum, manganese, gold, silver, copper, etc.

[0154] For example, when a lithium-ion secondary battery is selected as the target material, the magnetic separation process can separate magnetic materials such as iron contained in the crushed material from non-magnetic materials such as copper which is a valuable material.

[0155] Meanwhile, in the example where the above-mentioned lithium-ion secondary battery is the subject, the case in which a valuable material selected as a non-attachable material is included has been described; however, the present invention is not limited thereto, and depending on the type of subject, it may be in a form that includes, for example, a valuable material selected as an attachable material.

[0156] In addition, there are no specific restrictions on the magnetic force in the magnetic separation process as long as it is 0.03T (Tesla) or higher, and it can be appropriately selected according to the purpose; however, for example, when separating iron, it is preferable to set it to 0.01T (Tesla) or higher and 0.3T or lower. Also, when separating stainless steel, a magnetic force higher than the above range can be used. Meanwhile, it is also possible to use different magnetic forces in combination in multiple stages.

[0157] By doing so, the method for recovering valuable materials according to the present invention can selectively separate magnetic materials such as iron or stainless steel.

[0158] Other processes

[0159] There are no particular restrictions on other processes, and they can be appropriately selected depending on the purpose.

[0160] <Example of an embodiment>

[0161] Hereinafter, an example of an embodiment of the method for recovering valuable materials according to the present invention is described. Furthermore, this embodiment shows an example in which a lithium-ion secondary battery is selected as the target object.

[0162] In this embodiment, first, a lithium-ion secondary battery, which is the subject of the invention, is placed in a container, and the container is loaded onto a cart and moved while being heat-treated by a continuous furnace to obtain a heat-treated lithium-ion secondary battery. In addition, when performing the heat treatment, as shown in FIG. 1, a burner is placed at a point located between adjacent containers, and the heat treatment is performed so that the flame emitted from the burner does not come into contact with the cylindrical container, and while the cart and container are moving, the flame emitted from the burner is weakened compared to when the cart and container are stopped.

[0163] In addition, when performing heat treatment, the combustion state of the lithium-ion secondary battery is observed to determine whether the combustion of the lithium-ion secondary battery is complete, and when it is determined that the combustion of the lithium-ion secondary battery is complete, the heat treatment is terminated.

[0164] In addition, when heat treating, the lithium-ion secondary battery is heat treated at a temperature of 750°C or higher and less than 1085°C, and the aluminum contained in the lithium-ion secondary battery is melted and recovered as a molten material.

[0165] Next, the heat-treated material of the lithium-ion secondary battery is crushed to obtain crushed material, and the crushed material is classified into coarse product (material that did not pass through the sieve) and fine product (material that passed through the sieve). Here, copper (Cu) is separated and concentrated in the coarse product (material that did not pass through the sieve).

[0166] Next, magnetic separation is performed on the aggregated product (material that did not pass through the sieve) to separate the aggregated product (material that did not pass through the sieve) into magnetically attached and non-magnetic materials. At this time, iron (Fe) is separated and concentrated in the magnetically attached material, and copper (Cu), which is a valuable material, is separated and concentrated in the non-magnetic material.

[0167] In this way, in this embodiment, the lithium-ion secondary battery is efficiently heat-treated while suppressing the deterioration of the container, and copper can be recovered as a valuable material in a high quality with a high recovery rate.

[0168] [Example]

[0169] Embodiments of the present invention are described below, but the present invention is not limited to these embodiments.

[0170] (Example 1)

[0171] Heat Treatment

[0172] As the target material, the cathode material (cathode active material) is LiNi x Co y Mn z A prismatic lithium-ion secondary battery cell (approx. 100 kg) was used, in which O2 (x+y+z=1), the negative electrode material was carbon (graphite), and the outer case was made of aluminum. A pusher-type continuous furnace with a total length of 24.6 m (manufactured by Mino Ceramics Co., Ltd.) was used.

[0173] Ten carts with a floor area (loading area) of 2.2m × 2.2m were used in succession to be fed into the continuous furnace. An aluminum recovery support was placed on the cart, and a stainless steel cylindrical container (an example of a means for receiving objects) with a diameter of 0.6m and a height of 0.9m, having an aluminum drop opening at the bottom, was mounted in the center of the cart on the aluminum recovery support. Additionally, a clearance of 0.8m was provided from the cylindrical container to the front and rear ends of the cart, respectively.

[0174] Next, the lithium-ion secondary battery cells were filled into a cylindrical container. The furnace temperature (heat treatment temperature) in the continuous furnace was set to approximately 850°C.

[0175] The number of carts in the continuous furnace is always set to 8, and the carts are moved once every 60 minutes, with each movement lasting 32 seconds. That is, at the point when the cart movement is repeated 8 times (at the point of approximately 8 hours of heat treatment), the cart is discharged from the continuous furnace and heat is released.

[0176] In addition, in the continuous furnace, when stopping the cart and the cylindrical container and performing heat treatment, as shown in Fig. 1, a burner is placed at a point located between adjacent cylindrical containers (on both the left and right sides in the direction of travel of the cart) and heat treatment is performed so that the flame emitted from the burner does not come into contact with the cylindrical container.

[0177] Meanwhile, during heat treatment, flames from the burner are emitted from both the left and right sides in the direction in which the cart and cylindrical container proceed in the continuous furnace, ensuring that the flames do not come into contact with the tracks (rails) when the cart is moved.

[0178] Crushing and Classification

[0179] Next, a crushed lithium-ion secondary battery (heat-treated lithium-ion secondary battery, etc.) was crushed using a hammer crusher (Makino-type swing hammer crusher-HC-20-3.7, manufactured by Makino Industry Co., Ltd.) as a crushing device under conditions of 50 Hz (hammer circumferential speed 38 m / sec) and a punching metal hole diameter of 10 mm at the exit section, thereby obtaining a crushed lithium-ion secondary battery.

[0180] Next, the crushed lithium-ion secondary battery was sieved using a sieve with a mesh size (classification point) of 1.2 mm (diameter 200 mm, manufactured by Tokyo Screen Co., Ltd.). Thus, after sieving, the material that did not pass through the 1.2 mm sieve (coarse product) and the material that passed through the sieve (fine product) were collected separately.

[0181] Magnetic force screening

[0182] Next, regarding the obtained assembly product, magnetic separation was performed under the condition of a feed speed of 0.5 kg / min using a dry drum-type magnetic separator (CC 15"Φ×20"W, manufactured by Aries Magnetic Co., Ltd.) with a magnetic flux density of 1500 G (0.15 T), thereby separating and recovering magnetic materials and non-magnetic materials.

[0183] (Example 2)

[0184] In Example 1, a camera installed in the continuous furnace determined whether the ignition of the lithium-ion secondary battery inside the cylindrical container had ended during heat treatment at the position of the third cart from the furnace entrance, and when it was determined that the ignition of the lithium-ion secondary battery had ended, the combustion of the burners on the outlet side (positions 5 to 8), excluding the burners on both sides at the position of the fourth cart from the furnace entrance which are necessary to maintain the furnace temperature, was stopped; otherwise, the self-attached and non-attached materials were separated and recovered in the same manner as in Example 1. That is, in Example 2, the heat treatment time was shortened from approximately 8 hours in Example 1 to approximately 3 hours.

[0185] In addition, in Example 2, the combustion of the lithium-ion secondary battery was determined by confirming that the ignition from the lithium-ion secondary battery had ceased in the image of the camera illuminating the inside of the furnace.

[0186] (Comparative Example 1)

[0187] Except for the fact that in Example 1, a cart and a container were placed in a position where the flame emitted from the burner in the furnace of the continuous furnace directly contacted the cylindrical container and heat treatment was carried out for 3 hours, the magnetic material and the non-magnetic material were separated and recovered in the same manner as in Example 1.

[0188] <Evaluation>

[0189] <<Condition of cylindrical container after heat treatment>>

[0190] In the case of a cylindrical container (an example of a means for receiving objects) after heat treatment, an opening (damage) of Φ (diameter) 5 mm or more was evaluated as “X”, a deformation of 10 mm or more was confirmed as “△”, and no opening (damage) and a deformation of 10 mm or less was evaluated as “○”.

[0191] <<Recovered Items · Quality>>

[0192] The mass of the obtained fine-grained product, magnetic material, and non-magnetic material was measured using an electromagnetic balance (product name: GX-8K, manufactured by A&D Co., Ltd.). Subsequently, the residue of the leaching solution obtained by leaching the magnetic material and non-magnetic material, respectively, was heated and dissolved in aqua regia (manufactured by Fujifilm Wako Pure Chemical Co., Ltd.) and analyzed using a high-frequency inductively coupled plasma emission spectrometer (iCaP6300, manufactured by Thermo Fisher Scientific Co., Ltd.) to determine the copper content ratio (grade) in the fine-grained product, magnetic material, and non-magnetic material. In addition, the weight ratio (%) of copper recovered in the non-magnetic material was evaluated as the copper recovery rate, with the total weight of copper contained in all these products set to 100.

[0193] Table 1 shows the condition of the cylindrical container after heat treatment in Example 1, Example 2, and Comparative Example 1 (container condition), and the recovery rate and grade of copper (Cu) contained in the non-attached material of the assembly product.

[0194] Container status Copper recovery rate (%) Copper grade (%) Example 1 △ 85 87 Example 2 ○ 89 89 Comparative Example 1 X 14 63

[0195] As shown in Table 1, in Examples 1 and 2, the deterioration of the cylindrical container was suppressed so that no damage occurred, and furthermore, the copper recovery rate of the non-attached product of the assembly output was 80% or higher and the grade was also 80% or higher. Thus, in Examples 1 and 2, the deterioration of the cylindrical container could be suppressed and the lithium-ion secondary battery could be efficiently heat-treated, and copper, which is an example of a valuable material, could be recovered with a high grade due to the high recovery rate.

[0196] Meanwhile, in Comparative Example 1, the copper (Cu) current collector in the lithium-ion secondary battery was oxidized and embrittled as the cylindrical container deteriorated and broke, resulting in a reduced recovery rate of the assembly product, and consequently, the copper recovery rate from the non-attachment material was less than 20%.

[0197] As described above, the method for recovering valuable materials according to the present invention comprises a heat treatment process in which a continuous furnace is used to heat-treat a target while moving a target receiving means containing a target containing valuable materials, such that a flame for heat treatment does not come into contact with the target receiving means, and a valuable material recovery process in which valuable materials are recovered from a heat-treated target obtained by the heat treatment process.

[0198] Thus, in the method for recovering valuable materials according to the present invention, deterioration of the object receiving means for receiving an object containing valuable materials can be suppressed, and the object can be efficiently heat-treated to recover the valuable materials in high quality with a high recovery rate. Explanation of the symbols

[0199] 11 Seungon Waiting Room 12 Temperature-boosting section 13 Maintenance Department 14 Cooling Waiting Room 15 Moving Door 16 carts 17 Means of accommodating objects 18 Flames 19 Secondary combustion chamber 20 smoke passages

Claims

Claim 1 A method for recovering valuable materials, comprising: a heat treatment process in which a flame for heat treatment is applied to a target object containing valuable materials while moving a target object receiving means, such that the flame for heat treatment does not come into contact with the target object receiving means; and a valuable material recovery process in which the valuable materials are recovered from a heat-treated target object obtained by the heat treatment process, wherein in the heat treatment process, the flame is radiated from between adjacent target object receiving means so as not to come into contact with the target object receiving means when heat-treating a plurality of the target object receiving means. Claim 2 A method for recovering valuable materials according to claim 1, wherein in the heat treatment process, the means for receiving the object being moved is stopped and the flame is radiated so as not to come into contact with the means for receiving the object. Claim 3 delete Claim 4 A method for recovering valuable materials according to claim 1 or 2, wherein in the heat treatment process, the radiation of the flame is weakened while the object receiving means is moving compared to when the object receiving means is stopped. Claim 5 A method for recovering valuables according to paragraph 2, wherein in the heat treatment process, the ratio of the moving time for moving the object receiving means to the stopping time for stopping the object receiving means satisfies the inequality of stopping time / moving time ≥ 10. Claim 6 A method for recovering valuables according to claim 1 or 2, wherein the means for receiving the object is formed of iron or stainless steel. Claim 7 A method for recovering valuable materials according to claim 1 or 2, wherein the heat treatment process involves heat-treating the object at a temperature of 750°C or higher and less than 1085°C. Claim 8 A method for recovering valuable materials according to claim 1 or 2, wherein the object is a lithium-ion secondary battery. Claim 9 A method for recovering valuable materials according to claim 8, wherein the lithium-ion secondary battery comprises a case containing aluminum, and the heat treatment process involves melting the aluminum of the case in the lithium-ion secondary battery to separate the molten material. Claim 10 A method for recovering valuables according to claim 8, wherein the valuables include copper. Claim 11 A method for recovering valuable materials according to claim 8, wherein in the heat treatment process, the combustion state of the lithium-ion secondary battery is observed to determine whether the combustion of the lithium-ion secondary battery is completed, and the heat treatment is terminated when it is determined that the combustion of the lithium-ion secondary battery is completed. Claim 12 A method for recovering valuable materials according to claim 1 or 2, wherein the valuable material recovery process comprises a crushing process for obtaining crushed material by crushing the heat-treated material, a classification process for obtaining coarse product and fine product by classifying the crushed material by a classification point of 0.6 mm or more and 2.4 mm or less, and a magnetic separation process for separating the coarse product using a magnet having a magnetic flux density of 0.03 Tesla or more.

Images