Methods for recovering valuables

Abstract

A method for recovering valuables, comprising: a heat treatment step, using a continuous furnace that moves an object storage unit containing an object and heat-treats the object, wherein the object is heat-treated in a manner that a flame used for the heat treatment does not come into contact with the object storage unit; and a valuable recovery step, recovering the valuable from a heat-treated product of the object obtained by the heat treatment step.

Description

Technical Field

[0001] The present invention relates to a method for recovering valuables. Background Art

[0002] Compared with conventional lead-acid batteries and nickel-cadmium secondary batteries, lithium-ion secondary batteries are lightweight, high-capacity, and high-electromotive force secondary batteries, and are used as secondary batteries for personal computers, electric vehicles, portable devices, etc. For example, in the positive electrode of lithium-ion secondary batteries, valuable substances such as cobalt and nickel are used in the form of lithium cobalt oxide (LiCoO2), ternary positive electrode materials (LiNi x Co y Mn z O2(x+y+z=1)) and other forms are used.

[0003] Furthermore, since the use of lithium-ion secondary batteries is expected to expand in the future, from the perspective of resource recycling, it is desirable to recover valuables such as lithium and copper from defective products generated during the manufacturing process and from lithium-ion secondary batteries discarded due to equipment use and battery life. When processing lithium-ion secondary batteries to recover valuables, heat treatment is sometimes performed to deactivate and render the lithium-ion secondary batteries harmless. Recovering the various metals contained in the heat-treated product obtained by heat-treating the lithium-ion secondary batteries without oxidation (embrittlement) is important from the perspective of increasing the value of the recovered valuables.

[0004] As a method for preventing embrittlement of various metals contained in lithium-ion secondary batteries while performing heat treatment, for example, a treatment method has been proposed, which is a method of heating a lithium-ion battery. In this method, an incinerator that uses flames to incinerate an incineration object is used. When the lithium-ion battery is heated while preventing the shell of the lithium-ion battery from directly contacting the flame, the lithium-ion battery is arranged in a battery protection container in the incinerator that prevents the shell of the lithium-ion battery from directly contacting the flame, and the outer surface of the battery protection container is brought into contact with the flame, thereby heating the lithium-ion battery (for example, see Patent Document 1).

[0005] However, this conventional technology has problems such as the possibility of deformation or destruction of the battery protection container.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-207648 Summary of the Invention

[0009] Problems to be solved by the invention

[0010] As described above, in the prior art, the outer surface of the battery protective container protecting the lithium-ion secondary battery is exposed to flames, heating the lithium-ion secondary battery. This direct contact with the flames can cause the battery protective container to deteriorate, deform, or even break. Consequently, using the prior art can result in significant costs associated with manufacturing, replacing, or repairing the battery protective container.

[0011] Furthermore, in the above-mentioned prior art, if the battery protective container deteriorates and deforms or breaks, excessive heat is applied to the lithium-ion secondary battery inside the battery protective container, causing valuables such as copper recovered from the lithium-ion secondary battery to oxidize or become brittle, potentially reducing the recovery rate and quality of the recovered valuables.

[0012] Furthermore, in the above-mentioned prior art, a stationary furnace is used in the embodiments to heat-treat lithium-ion secondary batteries. However, when using a stationary furnace to continuously heat-treat lithium-ion secondary batteries, there is the following problem: if the furnace is not allowed to cool to a specified temperature (e.g., below 200°C) after the heat treatment, the next lithium-ion secondary battery cannot be placed in the furnace. This is because when using a stationary furnace to heat-treat lithium-ion secondary batteries, if the temperature inside the furnace is high, there is a risk of the lithium-ion secondary battery catching fire immediately after it is placed in the furnace. Therefore, the above-mentioned prior art cannot continuously heat-treat lithium-ion secondary batteries, and the efficiency (productivity) of the heat treatment is insufficient.

[0013] The present invention aims to solve the aforementioned problems and achieve the following objectives. Specifically, the present invention aims to provide a valuables recovery method that can suppress degradation of a storage unit for storing valuables, effectively heat-treat the valuables, and thereby recover the valuables at a high recovery rate and high quality.

[0014] Solutions for solving problems

[0015] As a means for solving the above-mentioned problem, the following are described.

[0016] <1> A method for recovering valuables, characterized in that it comprises:

[0017] a heat treatment step of heat-treating the object using a continuous furnace that moves an object storage unit that stores an object, wherein the object contains a valuable substance, so that a flame used for the heat treatment does not come into contact with the object storage unit; and

[0018] The valuable substance recovery step is to recover the valuable substance from the heat-treated product of the object obtained in the heat treatment step.

[0019] <2> The valuables recovery method according to <1>, wherein, in the heat treatment step, the moving object storage unit is stopped, and the flame is radiated so that the flame does not come into contact with the object storage unit.

[0020] <3> A method for recovering valuables according to any one of <1> to <2>, wherein, in the heat treatment step, when a plurality of the object storage units are heat-treated, the flame is radiated from between adjacent object storage units in a manner that does not contact the object storage units.

[0021] <4> The valuable recovery method according to any one of <1> to <3>, wherein, in the heat treatment step, the radiation of the flame is made weaker during the period when the object storage unit is moved than during the period when the object storage unit is stopped.

[0022] <5> The valuables recovery method according to any one of <2> to <4>, wherein, in the heat treatment step, a ratio of a stop time of the object storage unit to a movement time of the object storage unit satisfies the following inequality:

[0023] The aforementioned stop time / the aforementioned movement time ≥ 10.

[0024] <6> The valuable recovery method according to any one of <1> to <5>, wherein the object storage unit is formed of iron or stainless steel.

[0025] <7> The method for recovering a valuable substance according to any one of <1> to <6>, wherein in the heat treatment step, the object is heat-treated at 750°C or higher and lower than 1085°C.

[0026] <8> The method for recovering a valuable substance according to any one of <1> to <7>, wherein the target object is a lithium ion secondary battery.

[0027] <9> The method for recovering valuables according to <8>, wherein the lithium-ion secondary battery has a casing containing aluminum,

[0028] In the heat treatment step, the aluminum of the casing in the lithium-ion secondary battery is melted and the melt is separated.

[0029] <10> The method for recovering a valuable substance according to any one of <8> to <9>, wherein the valuable substance contains copper.

[0030] <11> The method for recovering valuables according to any one of <8> to <10>, wherein, in the heat treatment step, the combustion state of the lithium ion secondary battery is observed to determine whether the combustion of the lithium ion secondary battery is complete.

[0031] The heat treatment is terminated when it is determined that the combustion of the lithium ion secondary battery is complete.

[0032] <12> The method for recovering a valuable substance according to any one of <1> to <11>, wherein the valuable substance recovery step comprises:

[0033] a crushing step of crushing the aforementioned heat-treated product to obtain a crushed product;

[0034] a classification step of classifying the crushed product at a classification point of 0.6 mm or more and 2.4 mm or less to obtain a coarse particle product and a fine particle product; and

[0035] In the magnetic separation step, the coarse-grained product is separated using a magnet having a magnetic flux density of 0.03 Tesla or more.

[0036] Effects of the Invention

[0037] According to the present invention, various previous problems can be solved, and a valuables recovery method can be provided that can suppress the deterioration of an object storage unit that stores an object containing valuables, and can effectively heat-treat the object, thereby recovering the valuables with a high recovery rate and high quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a conceptual diagram showing an example of a continuous furnace that can be used in the valuable substance recovery method of the present invention. DETAILED DESCRIPTION

[0039] (Method for recovering valuables)

[0040] The valuable recovery method of the present invention includes a heat treatment step and a valuable recovery step, and may further include other steps as needed. Furthermore, the valuable recovery step in the valuable recovery method of the present invention preferably includes a crushing step, a classification step, and a magnetic separation step, and may further include other steps as needed.

[0041] The present invention's valuables recovery method is based on the following findings by the present inventors: In conventional techniques, when heat-treating objects such as lithium-ion secondary batteries (LIBs) to recover valuables such as copper, the object storage unit, such as the container, can deteriorate. Furthermore, the present invention's valuables recovery method is based on the following findings by the present inventors: Conventional techniques fail to effectively heat-treat objects, and the quality and recovery rate of the recovered valuables can be insufficient.

[0042] More specifically, as mentioned above, in the prior art, since the battery protection container that protects the lithium-ion secondary battery is in direct contact with the flame for heat treatment, the battery protection container may deteriorate and deform, or may be destroyed. Therefore, when using the prior art, the production / replacement and repair of the battery protection container may cost money. Furthermore, in cases where the battery protection container deteriorates and deforms / is destroyed, the valuables such as copper recovered from the lithium-ion secondary battery may be oxidized or embrittled, and the recovery rate and grade of the recovered valuables may be reduced. In addition, in the embodiments of the prior art described above, a stationary furnace is used to heat treat the lithium-ion secondary battery, and the lithium-ion secondary battery cannot be heat treated continuously, and the efficiency (productivity) of the heat treatment is insufficient.

[0043] Thus, the inventors discovered that when using the existing technology, the object storage unit for storing objects containing valuables deteriorates, and the efficiency of heat treatment of the objects is insufficient, and thus the objects cannot be effectively heat treated. In addition, the quality and recovery rate of the recovered valuables may be insufficient.

[0044] Therefore, the inventors of the present invention have repeatedly conducted in-depth research on a valuables recovery method that can suppress the deterioration of an object storage unit that stores an object containing valuables and can effectively heat-treat the object, thereby recovering the valuables with a high recovery rate and high quality, and have come up with the present invention.

[0045] That is, the present inventors have discovered that, by providing a valuables recovery method comprising: a heat treatment process for heat-treating the object in a manner such that the flame used for the heat treatment does not come into contact with the object holding unit using a continuous furnace that moves an object holding unit holding an object containing a valuable and performs heat treatment on the object; and a valuables recovery process for recovering the valuables from the heat-treated object obtained by the heat treatment process, deterioration of the object holding unit that holds an object containing a valuable can be suppressed, and the object can be effectively heat-treated, thereby recovering the valuables with a high recovery rate and high grade.

[0046] Here, in the valuable recovery method of the present invention, a continuous furnace is used to move an object storage unit containing an object containing a valuable and to heat treat the object, and the object is heat treated in a manner that the flame used for heat treatment does not come into contact with the object storage unit (heat treatment process).

[0047] Thus, in the present invention, heat treatment is performed using a continuous furnace that moves an object storage unit and heat treats the object. Therefore, in the present invention, by continuously loading multiple object storage units into the continuous furnace, the objects stored in the object storage units can be continuously heat treated, thereby enabling more efficient heat treatment of the objects, that is, the number of objects that can be heat treated per unit time can be increased.

[0048] Furthermore, in the present invention, as described above, the object is heat-treated in such a manner that the flame used for the heat treatment does not come into contact with the object storage unit. Therefore, the present invention can prevent the object storage unit from being overheated, and degradation of the object storage unit can be suppressed. Furthermore, since degradation of the object storage unit can be suppressed, the present invention can reduce maintenance costs such as replacement and repair of the object storage unit.

[0049] In addition, in the valuable material recovery method of the present invention, since the flame used for heat treatment does not come into contact with the object storage unit, the deterioration of the object storage unit can be suppressed. Therefore, for example, the oxidation and embrittlement of the valuable materials (such as copper, etc.) contained in the object caused by direct contact between the heat treatment flame and the object due to damage to the object storage unit can be suppressed. In the valuable material recovery process, the valuable materials can be recovered with a high recovery rate and high grade.

[0050] In this way, the valuables recovery method of the present invention can suppress the deterioration of the object storage unit that stores the object containing the valuables by including the above-mentioned heat treatment process and the valuables recovery process, and can effectively heat-treat the object, thereby recovering the valuables with a high recovery rate and high grade.

[0051] The following describes in detail the various steps and the like in the valuable material recovery method of the present invention.

[0052] Heat treatment process

[0053] The heat treatment process involves using a continuous furnace that moves an object storage unit containing an object containing a valuable and heat-treating the object, heat-treating the object in a manner that prevents the flame from coming into contact with the object storage unit. In other words, the heat treatment process involves, for example, irradiating the object contained in the object storage unit with a flame in a manner that prevents the object storage unit from coming into direct contact with the flame, heat-treating the object in the continuous furnace to produce a heat-treated product. It should be noted that the heat-treated product refers to the substance obtained by heat-treating the object.

[0054] <<Object / Value>>

[0055] The object contains a valuable substance and is not particularly limited as long as it can be accommodated in an object storage unit and heat-treated using a continuous furnace, and can be appropriately selected as needed. Examples of the object include secondary batteries such as lithium-ion secondary batteries and nickel-metal hydride batteries. Typically, lithium-ion secondary batteries are preferably used.

[0056] Valuables here refer to substances that are not discarded and can be traded, and examples include various metals. When the target object is a lithium-ion secondary battery, examples of valuables include high-quality carbon (C) concentrate, copper (Cu), aluminum (Al), lithium (Li), cobalt (Co), nickel (Ni), etc. It should be noted that high-quality carbon (C) concentrate (e.g., with a grade of 80% or higher) can be suitably used as a reducing agent in metal smelting, for example.

[0057] -Lithium-ion secondary battery-

[0058] There are no particular limitations on the lithium-ion secondary battery and it can be appropriately selected as needed. Examples include defective lithium-ion secondary batteries produced during the manufacturing process of the lithium-ion secondary battery, lithium-ion secondary batteries discarded due to defects in the equipment used, the life of the equipment used, etc., and used lithium-ion secondary batteries discarded due to their lifespan.

[0059] The shape, structure, size, and material of the lithium ion secondary battery are not particularly limited and can be appropriately selected as needed.

[0060] The shape of the lithium ion secondary battery is not particularly limited and can be appropriately selected as needed. Examples thereof include a laminated type, a cylindrical type, a button type, a coin type, a square type, and a flat type.

[0061] The form of lithium-ion secondary batteries is not particularly limited and can be appropriately selected as needed. Examples include battery cells, battery modules, and battery packs. Here, a battery module refers to a structure consisting of multiple battery cells (unit batteries) connected and assembled into a single housing, while a battery pack refers to a structure consisting of multiple battery modules assembled into a single housing. Battery packs may also include a controller and a cooling device.

[0062] Examples of lithium-ion secondary batteries include a lithium-ion secondary battery comprising a positive electrode, a negative electrode, a separator, an electrolyte solution containing an electrolyte and an organic solvent, and an outer container serving as a battery case for accommodating the positive electrode, negative electrode, separator, and electrolyte solution. It should be noted that the lithium-ion secondary battery may be in a state where the positive electrode, negative electrode, etc. are removed.

[0063] --positive electrode--

[0064] As the positive electrode, there is no particular restriction and it can be appropriately selected as needed. It is preferably provided with a positive electrode current collector and a positive electrode material containing at least any one of cobalt and nickel. As the shape of the positive electrode, there is no particular restriction and it can be appropriately selected as needed. For example, a flat plate, a sheet, etc. can be listed.

[0065] ---Positive electrode collector---

[0066] The shape, structure, size, material, etc. of the positive electrode current collector are not particularly limited and can be appropriately selected as needed.

[0067] Examples of the shape of the positive electrode current collector include a foil shape.

[0068] Examples of the material of the positive electrode current collector include stainless steel, nickel, aluminum, copper, titanium, and tantalum, among which aluminum is preferred.

[0069] The positive electrode material is not particularly limited and can be appropriately selected as needed. Examples thereof include positive electrode materials containing at least a positive electrode active material containing lithium and, if necessary, a conductive agent and a binder resin.

[0070] The positive electrode active material is not particularly limited and can be appropriately selected as needed, but preferably contains at least one of cobalt and nickel.

[0071] Examples of positive electrode active materials include lithium manganese oxide (LiMn2O4) known as LMO series, lithium cobalt oxide (LiCoO2) known as LCO series, and LiNi3O4 known as ternary series and NCM series. x Co y Mn z O2 (x+y+z=1), LiNi called NCA system x Co yAl z (x+y+z=1), lithium iron phosphate (LiFePO4), lithium cobalt nickel oxide (LiCo 1 / 2 Ni 1 / 2 O2), lithium titanate (Li2TiO3), etc. In addition, these materials can be used in combination as the positive electrode active material.

[0072] The conductive agent is not particularly limited and can be appropriately selected as needed. Examples thereof include carbon black, graphite, carbon fibers, and metal carbides.

[0073] The binder resin is not particularly limited and can be appropriately selected as needed. Examples thereof include homopolymers or copolymers of vinylidene fluoride, tetrafluoroethylene, acrylonitrile, ethylene oxide, and the like, and styrene-butadiene rubber.

[0074] --negative electrode--

[0075] The negative electrode is not particularly limited and can be appropriately selected as needed. However, it preferably includes a negative electrode current collector and a negative electrode active material containing carbon (C).

[0076] The shape of the negative electrode is not particularly limited and can be appropriately selected as needed. Examples thereof include a flat plate shape and a sheet shape.

[0077] ---Negative electrode collector---

[0078] The shape, structure, size, material, etc. of the negative electrode current collector are not particularly limited and can be appropriately selected as needed.

[0079] Examples of the shape of the negative electrode current collector include a foil shape.

[0080] Examples of the material of the negative electrode current collector include stainless steel, nickel, aluminum, copper, titanium, and tantalum, among which copper is preferred.

[0081] The negative electrode active material is not particularly limited as long as it contains carbon (C), and can be appropriately selected as needed. Examples thereof include carbon materials such as graphite and hard carbon, titanates, silicon, etc. These materials may be used in combination as the negative electrode active material.

[0082] The material of the outer container (casing) of the lithium ion secondary battery is not particularly limited and can be appropriately selected as needed. Examples thereof include aluminum, iron, stainless steel, and resin (plastic).

[0083] In the present invention, even when a lithium-ion secondary battery containing a large amount of aluminum, such as a lithium-ion secondary battery having an aluminum casing, is used as the target, the aluminum, an example of a valuable substance, can be melted during the heat treatment step and separated as a molten material. In other words, the valuable substance recovery method of the present invention preferably involves melting the aluminum in the casing of the lithium-ion secondary battery during the heat treatment step, and separating the molten material.

[0084] <Object storage unit>

[0085] The object storage unit is not particularly limited as long as it can store the object and be loaded into the continuous furnace. It can be appropriately selected as needed, and examples thereof include containers, cylindrical cans, and outer containers in lithium ion secondary battery packs or modules.

[0086] The material of the object storage unit is preferably, for example, a material having a higher melting point than the temperature (heat treatment temperature) during heat treatment in the continuous furnace. More specifically, the material of the object storage unit is preferably, for example, iron, stainless steel, etc. In other words, in the valuable recovery method of the present invention, the object storage unit is preferably formed of iron or stainless steel. In this way, degradation, deformation, breakage, etc. of the object storage unit during heat treatment can be further suppressed.

[0087] The size of the object storage unit is not particularly limited as long as it can accommodate the object and can be loaded into the continuous furnace. It can be appropriately selected as needed. For example, it is preferably set to a size that can be placed on a trolley in the continuous furnace. It is preferably set to a size that allows adjacent object storage units to not contact each other when each trolley carries the object storage unit, that is, a size that forms a gap between the object storage units.

[0088] The shape and structure of the object storage unit are not particularly limited as long as the object can be stored therein, and can be appropriately selected as needed.

[0089] The object storage unit preferably has an opening that allows gas to flow. In this case, the object storage unit preferably stores the lithium-ion secondary battery in a manner that prevents gas from flowing outside the opening. The opening in the storage container allows for control of the pressure and atmosphere within the storage container.

[0090] The shape of the opening is not particularly limited and may be appropriately selected as needed. Furthermore, the position of the opening in the object storage unit is not particularly limited as long as it allows gas to flow during heat treatment and may be appropriately selected as needed. It should be noted that a plurality of openings may be provided in the object storage unit.

[0091] Alternatively, a hole in the outer container of a lithium-ion secondary battery pack or module can be used as the opening. A lithium-ion secondary battery pack typically has holes for connecting charging and discharging cables and plugs to the electrical connections within the pack or module, and these holes can be effectively utilized as openings.

[0092] There is no particular limitation on the size (area) of the opening, which can be appropriately selected as needed. It is preferably 12.5% ​​or less, more preferably 6.3% or less relative to the surface area of ​​the object storage unit. By setting the size of the opening to be 12.5% ​​or less relative to the surface area of ​​the object storage unit, the oxidation of the valuable substances contained in the collector can be further suppressed during heat treatment. In the following, the area of ​​the opening relative to the surface area of ​​the object storage unit is sometimes referred to as the "aperture ratio". It should be noted that when a plurality of openings are provided in the object storage unit, the aperture ratio can be set to the sum of the areas of the openings relative to the surface area of ​​the object storage unit.

[0093] If the opening ratio in the object storage unit is within the preferred range, for example, when the atmosphere outside the object storage unit is an air atmosphere, the atmosphere inside the object storage unit during heat treatment can be set to a low-oxygen atmosphere.

[0094] Here, the object storage unit preferably has an openable and closable cover for storing the lithium-ion secondary battery. This allows the lithium-ion secondary battery to be easily stored in the object storage unit, and the heat-treated lithium-ion secondary battery (heat-treated object) can be easily removed after the heat treatment step.

[0095] The cover is not particularly limited and can be appropriately selected as needed.

[0096] The cover may be fixed to be openable and closable by hinges or the like, or may be opened and closed by removing the cover.

[0097] Continuous furnace

[0098] The continuous furnace used in the heat treatment process is not particularly limited as long as the object storage unit that stores the object can be moved and the flame used for the heat treatment does not come into contact with the object storage unit to heat the object, and can be appropriately selected as needed. Examples of continuous furnaces (tunnel furnaces) include pusher-type continuous furnaces.

[0099] Here, for example, if one wants to continuously process a lithium-ion secondary battery as the object using a batch furnace (batch furnace), the lithium-ion secondary battery to be processed next cannot be put into the furnace from the time the heat treatment of the lithium-ion secondary battery is completed until the heat release in the furnace is completed. However, by using a continuous furnace (tunnel furnace), a heat release area is provided after the heat treatment area, thereby continuously and effectively performing heat release of the lithium-ion secondary battery that has been heat treated previously and heat treatment of the lithium-ion secondary battery to be processed next.

[0100] Here, the flame used for the heat treatment can be radiated by, for example, a flame radiating unit provided in a continuous furnace. The flame radiating unit is not particularly limited and can be appropriately selected as needed, and examples thereof include a burner.

[0101] Furthermore, the air ratio (the ratio of the actual air volume to the theoretical air volume) in the burner, which is an example of the flame radiation unit, is preferably set to be no greater than 2. By setting the air ratio in the burner to be no greater than 2, it is possible to further suppress overheating of the space surrounding the burner and degradation of the object storage unit due to air supplied by the burner.

[0102] As a continuous furnace, for example, it is preferable that the moving object storage unit be stopped during the heat treatment process, radiating the flame so that the object storage unit does not come into contact with the flame. In other words, in the present invention, it is preferable that the moving object storage unit be stopped during the heat treatment process, radiating the flame so that the object storage unit does not come into contact with the flame. This can more reliably prevent the object storage unit from coming into contact with the flame.

[0103] More specifically, during the heat treatment process, it is preferable that the radiation of the flame be weaker while the object storage unit is moving than while the object storage unit is stationary. This can more reliably prevent the object storage unit from coming into contact with the flame.

[0104] When the radiation of the flame is weakened during the movement of the object storage unit compared to the period when the object storage unit is stopped, the output of the radiation of the flame can be further weakened (reduced) or the radiation of the flame can be stopped.

[0105] Furthermore, in a continuous furnace, for example, when heat treating multiple object storage units, it is preferable that the flame radiate between adjacent object storage units. In other words, in the present invention, when heat treating multiple object storage units, it is preferable that the flame radiate between adjacent object storage units in a manner that prevents the flame from coming into contact with the adjacent object storage units. This allows for more reliable prevention of contact between the object storage units and the flame when heat treating multiple object storage units.

[0106] Here, as a continuous furnace capable of radiating flames between adjacent object storage units, for example, a continuous furnace in which a flame radiation unit is arranged between adjacent object storage units when the object storage units are stopped for heating can be used.

[0107] Here, Figure 1 This is a conceptual diagram showing an example of a continuous furnace that can be used in the valuable substance recovery method of the present invention.

[0108] Figure 1 In the example shown, the continuous furnace includes a heating standby room 11, a heating unit 12, a holding unit 13, and a cooling standby room 14. There are operating doors 15 between the heating standby room 11 and the heating unit 12, and between the cooling standby room 14 and the holding unit 13, which can be opened and closed by oil pressure or the like. Figure 1 The continuous furnace shown is connected to a secondary combustion furnace 19 as an exhaust gas treatment unit via a flue 20 above the holding portion 13. Figure 1 This is a conceptual diagram of the interior of a continuous furnace as viewed from a horizontal direction.

[0109] Figure 1 In the example shown, object storage units 17 for storing objects are placed on ten carts 16, and the carts 16 and object storage units 17 are sequentially moved in the directions indicated by the arrows from the temperature rise waiting room 11 to the temperature rise section 12. Furthermore, when moving the carts 16 and object storage units 17, for example, by pushing the cart 16 located at the left end of the temperature rise section 12 in the direction of the arrow, the carts 16 come into contact with each other and push against each other, thereby enabling each cart 16 to move. It should be noted that Figure 1 In the illustrated example, while the carriage 16 and the object storage unit 17 are being moved, the radiation of the flame 18 is made weaker than while the carriage 16 and the object storage unit 17 are being stopped.

[0110] Here, in the temperature rising section 12, the flame 18 is radiated by the flame radiating unit in such a manner that the flame 18 does not come into contact with the object storage unit 17, and the object stored in the object storage unit 17 is heat-treated by the flame 18. More specifically, Figure 1 In the example shown, when the object storage unit 17 stops heating, a flame radiation unit is arranged between adjacent object storage units 17 to radiate flame 18 between the adjacent object storage units 17. Figure 1 In the example shown, the flame 18 is radiated from both the left and right sides of the traveling direction (direction indicated by the arrow) of the trolley 16 and the object storage unit 17 in the continuous furnace. Figure 1 In the example shown, the flame 18 is radiated in a direction toward the side of the object storage unit 17 so as not to come into contact with the object storage unit 17 .

[0111] in addition, Figure 1 In the example shown, flame 18 required for maintaining the temperature in the furnace is radiated in the holding portion 13. Next, the carriage 16 and the object storage unit 17 are moved to the cooling standby room 14 and cooled.

[0112] As described above, when heat treating an object by repeatedly stopping the flame radiation and moving the object storage unit, and radiating the flame so as not to contact the object storage unit to heat the object, the ratio of the stopping time of the object storage unit to the moving time of the object storage unit is not particularly limited as long as the object can be sufficiently heat treated, and can be appropriately selected as needed. The ratio of the stopping time of the object storage unit to the moving time of the object storage unit preferably satisfies the following inequality, for example:

[0113] Stop time / movement time ≥ 10.

[0114] When the ratio of the stop time to the movement time in the heat treatment process satisfies the above inequality, the movement time can be shortened relative to the stop time, thereby suppressing the temperature drop in the continuous furnace during heat treatment and enabling more efficient heat treatment.

[0115] Furthermore, the flame irradiation time for each stop of the object storage unit for flame irradiation is preferably 5 minutes to 3 hours. Setting the flame irradiation time to 5 minutes to 3 hours prevents insufficient heat treatment of the object (e.g., a lithium-ion secondary battery), suppresses embrittlement of the recovered valuables, and reduces the amount of fuel required for heat treatment.

[0116] In the present invention, when the target object is a lithium-ion secondary battery, it is preferred that during the heat treatment process, the combustion state of the lithium-ion secondary battery be observed to determine whether combustion of the lithium-ion secondary battery is complete, and the heat treatment be terminated when combustion of the lithium-ion secondary battery is determined to be complete. This allows the lithium-ion secondary battery to be heat treated without over- or under-treatment, further suppressing degradation of the target object storage unit, and allowing the heat treatment to be performed more efficiently and in a shorter time.

[0117] There is no particular limitation on the method for observing the combustion state of a lithium-ion secondary battery, and it can be appropriately selected as needed. Examples include visual inspection, analysis of images obtained with a camera, analysis of temperature information obtained with a temperature recording method, a thermocouple, or a radiation thermometer, and analysis of changes in gas (CO, CO2, O2, etc.) concentrations. Alternatively, these methods may be combined for use.

[0118] More specifically, for example, by confirming the disappearance of the fire originating from the object storage unit using an image from a camera installed in the furnace, opening the entrance of the furnace to an extent that the gas in the furnace does not leak out of the system, and visually confirming the disappearance of the fire originating from the object storage unit from outside the furnace, it is possible to determine whether the combustion of the lithium-ion secondary battery is complete.

[0119] When the combustion of the lithium ion secondary battery is determined to be complete, the heat treatment is terminated by, for example, completely stopping the flame in the continuous furnace or radiating the flame required to maintain the temperature in the continuous furnace without contacting the object storage unit.

[0120] <<Heat treatment conditions>>

[0121] The conditions for heat treating (heating) the object (heat treatment conditions) are not particularly limited as long as the components of the object can be brought into a state in which the valuables can be recovered in the valuables recovery step described later, and can be appropriately selected as needed.

[0122] Here, as heat treatment conditions, for example, heat treatment temperature, heat treatment time, atmosphere, etc. can be cited.

[0123] The heat treatment temperature refers to the temperature of the object (eg, lithium ion secondary battery) during the heat treatment. The heat treatment temperature can be measured by inserting a thermometer such as a thermocouple or thermistor into the object during the heat treatment.

[0124] The heat treatment temperature can be appropriately selected depending on the object.

[0125] Here, when the target object is a lithium-ion secondary battery, the heat treatment temperature is preferably above the melting point of the lithium-ion secondary battery casing (external container). Thus, if the lithium-ion secondary battery casing is made of metal, the casing can be melted during the heat treatment process. For example, by placing a tray under the lithium-ion secondary battery to recover the molten metal of the casing, the metal from the lithium-ion secondary battery electrodes can be easily separated and recovered.

[0126] More specifically, for example, when the shell of a lithium-ion secondary battery contains aluminum, it is preferred that the heat treatment temperature be set to 660°C or higher, which is the melting point of aluminum. In this way, during the heat treatment process, the aluminum contained in the shell of the lithium-ion secondary battery can be melted and recovered. That is, in the method for recovering valuables of the present invention, when a lithium-ion secondary battery having a shell containing aluminum is set as the object, in the heat treatment process, by heat-treating the lithium-ion secondary battery at 660°C or higher, the aluminum contained in the shell and other parts of the lithium-ion secondary battery (such as electrodes, etc.) can be easily sorted (separated), thereby easily recovering the aluminum from the shell.

[0127] When recycling aluminum from lithium-ion secondary battery casings, for example, during the heat treatment process, aluminum can be recovered by placing aluminum trays on a trolley in a continuous furnace. Furthermore, since aluminum has low viscosity, the movement of the trolley causes aluminum remaining inside the object storage unit to be shaken and drip onto the trays, further improving the aluminum recovery rate.

[0128] In the valuable recovery method of 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 preferably 750°C or higher and 900°C or lower.

[0129] By setting the heat treatment temperature to 750°C or above, the lithium in the positive active material of the lithium-ion secondary battery, Li(Ni / Co / Mn)O2, and the lithium in the LiPF6 in the electrolyte can be formed into substances soluble in aqueous solution such as lithium fluoride (LiF), lithium carbonate (Li2CO3), and lithium oxide (Li2O), which can be separated from impurities other than fluorine when the lithium is leached. In addition, by setting the heat treatment temperature to 750°C or above, the cobalt oxide and nickel oxide contained in the positive active material are reduced to metals, which can be grown to a particle size that is easily magnetically adsorbed in the magnetic separation process described later. In addition, the growth of the metal particle size is more likely to occur when the heat treatment is performed at a higher temperature.

[0130] Furthermore, by setting the heat treatment temperature to above 750°C (a temperature higher than 660°C, which is the melting point of aluminum) and below 1085°C (the melting point of copper), for example, when a lithium-ion secondary battery having a shell containing aluminum is used as the object, the aluminum derived from the shell can be separated and recovered, and the oxidation or embrittlement of the copper contained in the negative electrode collector can be further suppressed, thereby further improving the recovery rate and grade of copper.

[0131] As heat treatment time (time that object is heat treated), there is no particular restriction, can suitably select as needed, for example, be preferably more than 1 minute and below 10 hours, more preferably more than 1 minute and below 5 hours, particularly preferably more than 1 minute and below 3 hours.The heat treatment time can for example be the time until object reaches the above-mentioned heat treatment temperature, and the holding time can also be short.Be more than 1 minute and below 5 hours by heat treatment time, can suppress the cost that heat treatment spends, and favourable on the viewpoint that can improve heat treatment efficiency.

[0132] The atmosphere used in the heat treatment is not particularly limited and may be appropriately selected as needed. Examples thereof include an air atmosphere, an inert atmosphere, a reducing atmosphere, and a low-oxygen atmosphere.

[0133] Atmospheric atmosphere refers to an atmosphere using air.

[0134] Examples of the inert atmosphere include an atmosphere composed of nitrogen gas or argon gas.

[0135] The reducing atmosphere refers to an atmosphere containing CO, H 2 , H 2 S, SO 2 , etc. in an inert atmosphere such as nitrogen or argon, for example.

[0136] A low oxygen atmosphere refers to an atmosphere in which the oxygen partial pressure is 11% or less.

[0137] Among them, a low-oxygen atmosphere is preferred from the viewpoint of reducing oxidation of the object storage unit and valuable materials such as copper due to oxygen and being achievable by controlling the oxygen supply amount of the burner without requiring special atmosphere adjustment.

[0138] <Valuable Asset Recovery Process>

[0139] The valuable substance recovery step is a step of recovering valuable substances from the heat-treated product of the object obtained in the heat treatment step.

[0140] The valuable substance recovery step is not particularly limited as long as it can recover valuable substances from the heat-treated product, and may be appropriately selected as needed. However, as described above, it preferably includes a crushing step, a classification step, and a magnetic separation step.

[0141] <<Crushing process>>

[0142] The crushing step is a step of crushing the heat-treated product to obtain a crushed product.

[0143] The crushing step is not particularly limited as long as it is a step of crushing the heat-treated product (calcined product) to obtain a crushed product, and can be appropriately selected as needed.

[0144] The crushing step is preferably a step of crushing the heat-treated product by impact to obtain crushed products. For example, when a lithium-ion secondary battery is selected as the target product, when the casing of the lithium-ion secondary battery is melted during the heat treatment step, it is preferable to perform pre-crushing by cutting the heat-treated product using a cutting machine before applying impact to the heat-treated product.

[0145] Examples of methods for crushing by impact include methods in which the heat-treated material is thrown onto a rotating striking plate or dropped onto a collision plate to impart impact; and methods in which the heat-treated material is struck by a rotating striking member (beater), which can be performed using, for example, a hammer mill. Furthermore, methods for crushing by impact include methods in which a ball made of ceramic or the like is struck against the heat-treated material, which can be performed using a ball mill. Furthermore, crushing by impact can also be performed using, for example, a twin-screw crusher with a short blade width and blade length that crushes by compression.

[0146] Furthermore, as a method of crushing by impact, for example, a method of applying impact by hitting the heat-treated product with two rotating chains can be mentioned, and this can be performed using, for example, a chain mill.

[0147] Here, the heat-treated product of the lithium-ion secondary battery is fragmented by impact, thereby promoting the fragmentation of the positive electrode current collector (e.g., aluminum (Al)), but the negative electrode current collector (e.g., copper (Cu)) remains in a foil-like form without significant morphology change. Therefore, during the fragmentation process, the negative electrode current collector is ultimately cut, and in the classification process described later, a fragmented product can be obtained in a state in which valuable substances derived from the positive electrode current collector (e.g., aluminum) and valuable substances derived from the negative electrode current collector (e.g., copper (Cu)) can be effectively separated.

[0148] The crushing time in the crushing step is not particularly limited and can be appropriately selected as needed. For example, when the target object is a lithium ion secondary battery, the crushing time per 1 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.

[0149] Furthermore, as crushing conditions in the crushing step, for example, when using an impact / percussion crusher such as a chain mill or hammer mill, it is preferable to set the chain and hammer tip speed to 10 m / sec or higher and 300 m / sec or lower, and the residence time of the object in the crusher to 1 second or higher and 10 minutes or lower. In this way, the valuable recovery method of the present invention can crush components such as copper, aluminum, and Fe from the casing, which serve as positive electrode materials, without excessive crushing.

[0150] <<Grading process>>

[0151] The classification step is a step of classifying the crushed product at a classification point of 0.6 mm or more and 2.4 mm or less to obtain a coarse particle product and a fine particle product.

[0152] The classification step is not particularly limited as long as it is a step that can classify the crushed material at a classification point of 0.6 mm or more and 2.4 mm or less to obtain a coarse-grained product and a fine-grained product, and can be appropriately selected as needed. By performing the classification step, when the target material is a lithium-ion secondary battery, for example, copper (Cu), iron (Fe), aluminum (Al), etc. can be separated into a coarse-grained product, and lithium (Li), cobalt (Co), nickel (Ni), manganese (Mn), carbon (C), etc. can be separated into a fine-grained product.

[0153] The classification step can be performed using, for example, a vibrating screen, a multi-stage vibrating screen, a cyclone separator, or a standard sieve of JIS Z8801.

[0154] The particle size for classification (classification point, sieve aperture) is preferably 0.6 mm to 2.4 mm, more preferably 0.85 mm to 1.7 mm, particularly preferably about 1.2 mm.

[0155] By setting the classified particle size to below 2.4 mm, the mixing of copper (Cu), iron (Fe), aluminum (Al), etc. into fine-grained products can be suppressed. By setting the classified particle size to above 0.6 mm, the mixing of carbon (C), lithium (Li), cobalt (Co), nickel (Ni), manganese (Mn), etc. into coarse-grained products can be suppressed.

[0156] In addition, the screening (classification) of the oversize (coarse-grained product) and undersize (fine-grained product) can be repeated multiple times. Through this re-screening, the impurity level of each product can be further reduced.

[0157] It should be noted that the crushing step and the classification step can also be carried out simultaneously. For example, the crushing step and the classification step can be carried out in the form of a crushing / classification step (crushing / classification) in which the heat-treated product obtained by the heat treatment step is crushed and the crushed product is classified into a coarse-grained product and a fine-grained product.

[0158] <<Magnetic separation process>>

[0159] The magnetic separation process involves sorting the coarse-grained product using a magnet with a magnetic flux density of 0.03 Tesla or higher. In other words, the magnetic separation process uses magnetic force to separate the crushed material, recovering valuables from the target material (the crushed material obtained by heat-treating and pulverizing the target material). It should be noted that, below, sorting using magnetic force may sometimes be referred to as "magnetic force sorting" or "magnetic sorting."

[0160] The magnetic separation step can be performed using a known magnetic sorter or the like.

[0161] As the magnetic separator that can be used in the present invention, there is no particular limitation and it can be appropriately selected as needed. For example, a magnetic bar, a lattice magnet, a rotary magnet, a magnetic filter, a high magnetic pulley (magnetic pulley) magnetic separator, a drum magnetic separator, a suspension magnetic separator, etc. can be listed. Among them, in the present invention, a drum magnetic separator and a suspension magnetic separator are preferably used.

[0162] In the magnetic separation step, for example, separation is performed according to the type of the object (the type of valuables contained in the object) by using a magnetic force capable of separating magnetically attracted substances and non-magnetically attracted substances contained in the object.

[0163] Here, a magnetically attractable substance refers to a substance that can be attracted to a magnetic source (magnetic field) by the magnetic force generated by the magnetic source (e.g., a magnet, electromagnet, etc.). Examples of magnetically attractable substances include ferromagnetic metals. Examples of ferromagnetic metals include iron, nickel, and cobalt.

[0164] A non-magnetic adsorbent refers to a substance that is not attracted to the magnetic source when the magnetic force generated by the magnetic source is utilized. There are no particular limitations on the non-magnetic adsorbent and it can be selected as needed. Furthermore, examples of metallic non-magnetic adsorbents include paramagnetic or diamagnetic metals. Examples of paramagnetic or diamagnetic metals include aluminum, manganese, gold, silver, and copper.

[0165] For example, when lithium-ion secondary batteries are selected as the target object, magnetically adsorbed materials such as iron contained in the crushed material can be separated from non-magnetically adsorbed materials such as copper as a valuable substance in the magnetic separation step.

[0166] It should be noted that in the above-mentioned example of lithium-ion secondary batteries as the object, the situation where non-magnetic adsorbents contain sorted valuable substances is described, but the present invention is not limited to this. Depending on the type of object, for example, it can be in the form of magnetically adsorbed objects containing sorted valuable substances.

[0167] In addition, the magnetic force in the magnetic separation process is not particularly limited as long as it is 0.03T (Tesla) or more, and can be appropriately selected as needed. For example, in the case of iron separation, it is preferably 0.01T (Tesla) or more and 0.3T or less. In addition, in the case of stainless steel separation, a magnetic force higher than the above range can be used. It should be noted that different magnetic forces can also be combined and used in multiple stages.

[0168] Thus, in the valuables recovery method of the present invention, magnetically adsorbed substances such as iron and stainless steel can be selectively separated.

[0169] <Other Process>

[0170] The other steps are not particularly limited and can be appropriately selected as needed.

[0171] <Example of Implementation>

[0172] Here, an example of an embodiment of the method for recycling lithium-ion secondary batteries of the present invention will be described. In addition, this embodiment shows an example in which lithium-ion secondary batteries are selected as the target object.

[0173] In this embodiment, the lithium ion secondary battery as the object is first placed in a container, the container is mounted on a trolley and moved, and heat treated in a continuous furnace to obtain a heat-treated lithium ion secondary battery. Figure 1 As shown, a burner is arranged between adjacent containers, and the cylindrical container is not exposed to the flame radiated by the burner for heat treatment. During the period of moving the trolley and the container, the radiation from the burner flame is made weaker than during the period of stopping the trolley and the container.

[0174] Furthermore, during the 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. When it is determined that the combustion of the lithium ion secondary battery is complete, the heat treatment is terminated.

[0175] In addition, when heat-treating, the lithium-ion secondary battery is heat-treated at 750° C. or higher and lower than 1085° C. to melt aluminum contained in the lithium-ion secondary battery and recover the aluminum as a melt.

[0176] The heat-treated product of the lithium-ion secondary battery is then crushed to obtain a crushed product, which is then classified into a coarse product (oversize) and a fine product (undersize). Here, copper (Cu) is separated and concentrated in the coarse product (oversize).

[0177] Next, the coarse product (oversize) is separated by magnetic force (magnetic separation) into magnetically adsorbed and non-magnetically adsorbed materials. Here, iron (Fe) is separated and concentrated in the magnetically adsorbed materials, while copper (Cu), a valuable substance, is separated and concentrated in the non-magnetically adsorbed materials.

[0178] As described above, in this embodiment, degradation of the container can be suppressed, and the lithium ion secondary battery can be efficiently heat-treated, thereby recovering copper as a valuable material at a high recovery rate and high quality.

[0179] Example

[0180] The following describes examples of the present invention, but the present invention is not limited to these examples.

[0181] (Example 1)

[0182] Heat treatment

[0183] As the object, the positive electrode material (positive electrode active material) used is LiNi x Co y Mn z A rectangular lithium-ion secondary battery cell (approximately 100 kg) was prepared using O2 (x+y+z=1), carbon (graphite) as the negative electrode material, and an aluminum outer casing. A 24.6 m long pusher-type continuous furnace (manufactured by Mino Ceramics Co., Ltd.) was used as the continuous furnace.

[0184] Ten trolleys with a 2.2m x 2.2m floor area (the loading platform area) were used as trolleys for loading into the continuous furnace. Aluminum collection trays were placed on the trolleys. A 0.6m diameter, 0.9m high, stainless steel cylindrical container (an example of an object storage unit) with an opening at the bottom for aluminum dripping was placed in the center of the trolleys. A 0.8m space was provided from the cylindrical container to the front and rear ends of the trolleys.

[0185] In addition, the interval between rails when the trolley is moved is 1.2 m.

[0186] Next, the above-mentioned lithium ion secondary battery cell was placed in a cylindrical container. The furnace temperature (heat treatment temperature) in the continuous furnace was set at approximately 850°C.

[0187] The number of trolleys in the continuous furnace is always set at 8. The trolleys are moved every 60 minutes, with each movement taking 32 seconds. In other words, after the trolley movement is repeated 8 times (after about 8 hours of heat treatment), the trolley is removed from the continuous furnace to release heat.

[0188] In addition, when the trolley and cylindrical container are stopped for heat treatment in the continuous furnace, Figure 1 As shown, burners are arranged between adjacent cylindrical containers (on the left and right sides of the traveling direction of the carriage), and the cylindrical containers are heat-treated without coming into contact with the flame radiated from the burners.

[0189] During the heat treatment, flames were radiated from the burners to the left and right of the traveling direction of the trolley and the cylindrical container in the continuous furnace, and the rails used for moving the trolley did not come into contact with the flames.

[0190] Crushing and grading

[0191] Next, a hammer crusher (Makino type swing hammer crusher HC-20-3.7, manufactured by Makino Sangyo Co., Ltd.) was used as a crushing device. Under the conditions of 50 Hz (hammer peripheral speed 38 m / s) and a hole diameter of 10 mm in the punching metal of the outlet part, the heat-treated lithium ion secondary battery (heat-treated product of the lithium ion secondary battery) was crushed to obtain a crushed product of the lithium ion secondary battery.

[0192] The crushed lithium ion secondary battery was then sieved (classified) using a sieve with a mesh size (classification point) of 1.2 mm (200 mm diameter, manufactured by TOKYO SCREEN CO., LTD.) and the 1.2 mm sieve-surface (coarse particles) and the sieve-underface (fine particles) were collected.

[0193] <Magnetic separation>

[0194] Next, the obtained coarse-grained product was magnetically separated using a dry drum magnetic separator (CC15 "φ×20" W, manufactured by Eriez Magnetics Co., Ltd.) with a magnetic flux density of 1500G (0.15T) at a feed rate of 0.5kg / min to separate and recover the magnetically adsorbed and non-magnetically adsorbed materials.

[0195] (Example 2)

[0196] In Example 1, a camera installed inside the continuous furnace determines whether the ignition of the lithium-ion secondary battery in the cylindrical container has ended during heat treatment at the third trolley from the furnace entrance. Upon determining that the ignition of the lithium-ion secondary battery has ended, the burners on the exit side (positions 5 to 8) are stopped, except for the burners on both sides of the position of the fourth trolley from the furnace entrance, which are required to maintain the temperature within the furnace. Otherwise, the magnetically attracted and non-magnetically attracted materials are separated and recovered in the same manner as in Example 1. In other words, in Example 2, the heat treatment time is shortened from approximately 8 hours in Example 1 to approximately 3 hours.

[0197] In Example 2, whether or not the combustion of the lithium ion secondary battery is complete is determined by confirming that the ignition from the lithium ion secondary battery has disappeared using an image captured by a camera inside the furnace.

[0198] (Comparative Example 1)

[0199] In Example 1, a trolley and a container are arranged in a continuous furnace at a position where the flame radiated by the burner is in direct contact with the cylindrical container, and heat treatment is performed for 3 hours. In addition, the magnetically adsorbed and non-magnetically adsorbed materials are separated and recovered in the same manner as in Example 1.

[0200] <Evaluation>

[0201] <<State of cylindrical container after heat treatment>>

[0202] For cylindrical containers (an example of an object storage unit) after heat treatment, the case where an opening (damage) of φ (diameter) of 5 mm or more is generated in the cylindrical container is evaluated as "×", the case where a deformation of 10 mm or more is confirmed is evaluated as "△", and the case where there is no opening (damage) and the deformation is within 10 mm is evaluated as "0".

[0203] <<Recovery rate / grade>>

[0204] The mass of the obtained fine-grained product, magnetic adsorbate and non-magnetic adsorbate was measured using an electromagnetic balance (trade name: GX-8K, manufactured by A&D Co., Ltd.). The residue of the leachate obtained by leaching the magnetic adsorbate and non-magnetic adsorbate was then heated and dissolved in aqua regia (manufactured by FUJIFILM Wako Pure Chemical Corporation) and analyzed by a high-frequency inductively coupled plasma emission spectrometer (iCaP6300, manufactured by Thermo Fisher Scientific KK) to determine the copper content (grade) in the fine-grained product, magnetic adsorbate and non-magnetic adsorbate. In addition, the weight ratio (%) of the copper recovered in the non-magnetic adsorbate when the weight of the copper contained in all these products is set to 100 was evaluated as the recovery rate of copper.

[0205] Table 1 shows the state of the cylindrical container after heat treatment (container state) in Example 1, Example 2, and Comparative Example 1, as well as the recovery rate of copper (Cu) contained in the non-magnetic adsorbent of the coarse particle product and the grade of copper (Cu).

[0206] [Table 1]

[0207]

[0208] As shown in Table 1, in Examples 1 and 2, degradation of the cylindrical container was suppressed, no damage occurred, and the recovery rate of copper from the non-magnetically adsorbed material in the coarse-grained product was 80% or higher, and the copper grade was also 80% or higher. Thus, in Examples 1 and 2, degradation of the cylindrical container was suppressed, and lithium-ion secondary batteries could be efficiently heat-treated, allowing copper, an example of a valuable material, to be recovered at a high recovery rate and high grade.

[0209] On the other hand, in Comparative Example 1, the cylindrical container deteriorated and broke, and the copper (Cu) collector in the lithium-ion secondary battery oxidized and became brittle, thereby reducing the recovery rate of the coarse-particle product. As a result, the recovery rate of copper in the non-magnetic adsorbent was less than 20%.

[0210] As described above, the valuable asset recovery method of the present invention includes: a heat treatment process, using a continuous furnace that moves an object storage unit that stores an object containing a valuable asset and heat-treats the object, and heat-treating the object in a manner that the flame used for heat treatment does not contact the object storage unit; and a valuable asset recovery process, recovering the valuable asset from the heat-treated object obtained by the heat treatment process.

[0211] Therefore, when using the organic matter recovery method of the present invention, the degradation of the object storage unit that stores the object containing the valuable can be suppressed, and the object can be effectively heat-treated, thereby recovering the valuable with a high recovery rate and high quality.

[0212] Description of Reference Numerals

[0213] 11 Heating waiting room

[0214] 12. Heating section

[0215] 13. Maintaining part

[0216] 14 Cooling waiting room

[0217] 15 Operation door

[0218] 16 cars

[0219] 17 Object storage unit

[0220] 18 Flame

[0221] 19 Secondary combustion furnace

[0222] 20 Flue

Claims

1. A method for recovering valuables, characterized in that: It includes: a heat treatment step of heat-treating the object using a continuous furnace that moves an object storage unit that stores an object, wherein the object contains a valuable; and heat-treating the object in such a manner that a flame used for the heat treatment does not come into contact with the object storage unit. and a valuable substance recovery step of recovering the valuable substance from the heat-treated product of the object obtained in the heat treatment step; Here, in the heat treatment step, when the plurality of object storage units are heat-treated, the flame is radiated from between adjacent object storage units so as not to come into contact with the object storage units.

2. The method for recovering valuables according to claim 1, wherein: In the heat treatment step, the moving object storage unit is stopped, and the flame is radiated so that the flame does not come into contact with the object storage unit.

3. The method for recovering valuables according to claim 1 or 2, wherein: In the heat treatment step, while the object storage unit is being moved, the radiation of the flame is made weaker than while the object storage unit is being stopped.

4. The method for recovering valuables according to claim 2, wherein: In the heat treatment step, a ratio of a stop time of stopping the object storage unit to a moving time of moving the object storage unit satisfies the following inequality: The stopping time / the moving time is ≥10.

5. The method for recovering valuables according to claim 1 or 2, wherein: The object accommodation unit is formed of iron or stainless steel.

6. The method for recovering valuables according to claim 1 or 2, wherein: In the heat treatment step, the object is heat treated at 750° C. or higher and lower than 1085° C.

7. The method for recovering valuables according to claim 1 or 2, wherein: The object is a lithium-ion secondary battery.

8. The method for recovering valuables according to claim 7, wherein: The lithium-ion secondary battery has a casing containing aluminum. In the heat treatment step, aluminum of the case in the lithium-ion secondary battery is melted and the melt is separated.

9. The method for recovering valuables according to claim 7, wherein: The valuable substance contains copper.

10. The method for recovering valuables according to claim 7, wherein: In the heat treatment step, the combustion state of the lithium ion secondary battery is observed to determine whether the combustion of the lithium ion secondary battery is complete. The heat treatment is terminated when it is determined that the combustion of the lithium ion secondary battery is completed.

11. The method for recovering valuables according to claim 1 or 2, wherein: The valuable substance recovery process includes: a crushing step of crushing the heat-treated product to obtain a crushed product; a classification step of classifying the crushed product at a classification point of 0.6 mm or more and 2.4 mm or less to obtain a coarse particle product and a fine particle product; and In the magnetic separation step, a magnet with a magnetic flux density of 0.03 Tesla or more is used to separate the coarse-grained product.

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