How to deal with used batteries

Abstract

The present invention relates to a method for treating waste batteries, which comprises the following steps: preparing waste batteries including waste positive electrodes, wherein the waste positive electrodes include an aluminum current collector and a positive electrode active material layer formed on at least one surface of the aluminum current collector; heat-treating the waste batteries at a temperature of 650° C. or higher in an air atmosphere or an oxidizing atmosphere to convert the aluminum current collector into aluminum oxide; and recovering aluminum oxide powder and positive electrode active material powder from the heat-treated waste batteries.

Description

Technical Field

[0001] The present invention relates to a method for processing waste batteries, and more particularly to a method for processing waste batteries developed as follows, wherein the method is developed so that waste positive electrodes can be pulverized and recovered in a simple process without using crushing equipment. Background Art

[0002] Lithium secondary batteries are generally composed of a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, a separator, and an electrolyte. Charging and discharging are performed by the intercalation and deintercalation of lithium ions. Lithium secondary batteries have been used in various fields because they have advantages such as high energy density and high electromotive force, as well as high capacity.

[0003] The positive electrode of a lithium secondary battery includes a positive electrode active material layer formed on the surface of a positive electrode current collector, and the positive electrode active material contains transition metals such as nickel, cobalt and manganese, and lithium, wherein nickel and cobalt are relatively expensive metals, and in particular, due to the limited number of countries producing cobalt, cobalt is known as a metal with unstable global supply and demand. Therefore, when the valuable metals contained in the positive electrode active material are recovered from waste batteries, especially waste positive electrodes, and recycled as raw materials, not only can the price competitiveness be guaranteed, but also additional income can be generated. Recently, attempts have been made to study methods for recovering and reusing valuable metals from waste batteries.

[0004] Traditionally, a melting method has been developed to recover valuable metals from used batteries. This involves placing the used batteries in a high-temperature furnace to thermally decompose them, melting them, and recovering the valuable metals in the form of alloys. However, this melting method requires high energy costs and has processing cost disadvantages due to equipment investment and waste gas treatment costs.

[0005] Therefore, in order to reduce processing costs, a method has been studied in which a pretreatment process is performed in which waste batteries are ground and classified by mechanical friction using a pulverizing device, the waste electrodes are pulverized, and then the powder is introduced into an acidic solution to extract valuable metals. Figure 1 The traditional waste battery pre-processing process using shredding equipment is described. Figure 1 As shown, the traditional pretreatment process according to the mechanical pulverization method is carried out in such a manner that after the waste batteries are subjected to primary crushing (coarse grinding, crushing) and subsequently heat-treated to remove binder components or electrolyte solution components, the waste batteries are crushed and finely ground through a secondary grinding and classification process to become micron-sized fine powder.

[0006] However, mechanical pulverization methods pose the risk of fire and dust explosion when the micron-sized fine powder comes into contact with metallic lithium and moisture contained in the battery. Furthermore, since the positive electrode current collector is also ground during the pulverization process, a large amount of materials (e.g., aluminum) contained in the positive electrode current collector is included as impurities in the final recovered powder. Therefore, the recovered powder must undergo a separate impurity removal process, which has the limitation of reducing the recovery rate of valuable metals due to the loss of valuable metals during the above-mentioned refining process. Furthermore, a separate pulverization / fine grinding device must be installed to form the fine powder.

[0007] Therefore, there is a need to develop a method for treating spent batteries that can reduce treatment costs and effectively recover positive electrode active materials without using pulverization / fine grinding equipment.

[0008] <Prior Art Documents>

[0009] (Patent Document 1) Japanese Patent Application Laid-Open No. 2015-185471 Summary of the Invention

[0010] Technical issues

[0011] One aspect of the present invention provides a method for treating waste batteries, which can effectively recover positive electrode active materials by pulverizing the waste batteries without facilities such as crushing / fine grinding equipment.

[0012] Technical Solution

[0013] According to one aspect of the present invention, a method for treating waste batteries is provided, the method comprising: preparing a waste battery comprising a waste positive electrode, the waste positive electrode comprising an aluminum current collector and a positive electrode active material layer formed on at least one surface of the aluminum current collector; heat-treating the waste battery at a temperature of 650° C. or above in an air atmosphere or an oxidizing atmosphere, thereby converting the aluminum current collector into aluminum oxide; and recovering aluminum oxide powder and positive electrode active material powder from the heat-treated waste battery.

[0014] Beneficial effects

[0015] The present invention's waste battery processing method heat-treats waste batteries, including waste positive electrodes, at temperatures above 650°C in air or an oxidizing atmosphere, converting the aluminum contained in the aluminum current collector into aluminum oxide powder. This pulverizes the positive electrode current collector and positive electrode active material without a pulverization process. Therefore, the method of the present invention reduces costs by eliminating the need for additional equipment for the grinding process. Furthermore, the method reduces the risk of explosion during the grinding process and offers excellent stability.

[0016] Furthermore, according to the method of the present invention, since the aluminum current collector is converted into aluminum oxide, which is not easily leached in acidic solutions, the amount of aluminum leached in acidic solutions is significantly reduced. Consequently, since the aluminum refining process can be minimized during the leaching of valuable metals, the loss of valuable metals during the aluminum refining process can be minimized, and the recovery rate of valuable metals can be improved.

[0017] As described above, according to the waste battery processing method of the present invention, since waste batteries can be pulverized without using crushing equipment, the positive electrode active material can be effectively recovered through a simple process and excellent results can be obtained in terms of processing cost and process safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The following drawings attached to the specification illustrate preferred embodiments of the present invention by way of example and are used to further understand the technical concept of the present invention together with the detailed description of the present invention given below. Therefore, the present invention should not be interpreted solely by the matters in these drawings.

[0019] Figure 1 is a flow chart illustrating the conventional waste battery processing process.

[0020] Figure 2 It is a flow chart illustrating the waste battery processing process of the present invention.

[0021] Figure 3 are photographs showing the state changes of the positive electrode waste before and after heat treatment by the method of Example 1; and

[0022] Figure 4 These are photographs showing the state changes of the positive electrode scrap heat-treated by the method of Comparative Example 1 before and after the heat treatment. DETAILED DESCRIPTION

[0023] Hereinafter, the present invention will be described in more detail.

[0024] It is understood that the words or terms used in the specification and claims should not be interpreted as the meanings defined in commonly used dictionaries. It is also understood that the inventor can appropriately define the meanings of the words or terms to best explain the principles of the present invention. These words or terms should be interpreted as having meanings that are consistent with their meanings in the relevant technical context and the technical ideas of the present invention.

[0025] The terms used herein are used only to describe particular example embodiments and are not intended to limit the present invention. In the specification, a term in the singular may include a plural form unless mentioned otherwise.

[0026] It should be further understood that the terms "include", "comprises" or "has" used in this specification refer to the presence of the stated features, numbers, steps, elements or combinations thereof, but do not exclude the presence or addition of one or more other features, numbers, steps, elements or combinations thereof.

[0027] Hereinafter, the method for treating waste batteries of the present invention will be described in detail.

[0028] The method for treating waste batteries of the present invention comprises the following steps: (1) preparing a waste battery including a waste positive electrode, wherein the waste positive electrode is composed of an aluminum current collector and a positive electrode active material layer formed on the surface of the aluminum current collector, (2) heat-treating the waste battery at a temperature of 650° C. or above in an air atmosphere or an oxidizing atmosphere to convert the aluminum current collector into aluminum oxide, and (3) recovering aluminum oxide powder and positive electrode active material powder from the heat-treated waste battery.

[0029] Figure 2 It is a flow chart for explaining the method for treating waste batteries of the present invention.

[0030] Next, we will combine Figure 2 Each step of the present invention is described in more detail.

[0031] First, used batteries including used positive electrodes are prepared ( S10 ).

[0032] The waste batteries in the present invention are such a concept: including all electrode wastes generated in the process of secondary battery preparation, defective batteries generated in the process of secondary battery preparation, or secondary batteries discarded after use.

[0033] The used battery may include a used positive electrode, and in this case, the used positive electrode includes an aluminum current collector and a positive electrode active material layer formed on at least one surface of the aluminum current collector. If necessary, the used battery may also include a used negative electrode.

[0034] The positive electrode active material layer may include a positive electrode active material, a binder, and / or a conductive agent.

[0035] The positive electrode active material may be a common positive electrode active material used in the art, for example, may be a lithium transition metal oxide.

[0036] Preferably, the positive electrode active material may be a positive electrode active material including lithium and at least one transition metal selected from nickel, cobalt, and manganese. As specific examples, the positive electrode active material may include lithium cobalt oxide (LiCoO2); lithium nickel oxide (LiNiO2); Li[Ni a Co b Mn c M 1 d ]O2(where M 1is at least one element selected from the group consisting of aluminum (Al), gallium (Ga) and indium (In), 0.3≤a<0.1, 0≤b≤0.5, 0≤c≤0.5, 0≤d≤0.1 and a+b+c+d=1); layered compounds such as Li (Li e M 2 f-e-f’ M 3 f’ )O 2-g A g (where 0≤e≤0.2, 0.6≤f≤1, 0≤f'≤0.2, 0≤g≤0.2, M 2 The present invention comprises manganese (Mn) and at least one selected from the group consisting of nickel (Ni), cobalt (Co), iron (Fe), chromium (Cr), vanadium (V), copper (Cu), zinc (Zn) and titanium (Ti), wherein Mn 3 is at least one selected from the group consisting of Al, magnesium (Mg) and boron (B), and A is at least one selected from the group consisting of phosphorus (P), fluorine (F), sulfur (S) and nitrogen (N), or a compound substituted with at least one transition metal; lithium manganese oxide, such as Li 1+h Mn 2-h O4 (where 0≤h≤0.33), LiMnO3, LiMn2O3 and LiMnO2; the chemical formula is LiNi 1-i M 4 i O2 (where M 4 =Co, Mn, Al, Cu, Fe, Mg, B or Ga, and 0.01≤i≤0.3) nickel-type lithium nickel oxide; chemical formula LiMn 2-j M 5 j O2 (where M 5 =Co, Ni, Fe, Cr, Zn or tantalum (Ta, and 0.01≤j≤0.1) or Li2Mn3M 6 O8 (where M 6 =Fe, Co, Ni, Cu or Zn) lithium manganese composite oxide; or LiMn2O4 in which part of lithium (Li) is replaced by alkaline earth metal ions. Preferably, the positive electrode active material may be nickel cobalt manganese lithium oxide, which includes nickel, cobalt and manganese as transition metals.

[0037] The role of the binder is to improve the bonding between the electrode active material particles and the adhesion between the electrode active material and the current collector, wherein the common electrode binders used in the art can be used. Specific examples of the binder can be polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HEP), polyvinyl alcohol, polyacrylonitrile, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated EPDM, styrene-butadiene rubber (SBR), fluororubber or its various copolymers, and a single one or a mixture of two or more thereof can be used.

[0038] The conductive agent is used to provide conductivity to the electrode, and any conductive agent can be used without particular limitation, as long as it has electronic conductivity and does not cause adverse chemical changes in the battery. Specific examples of the conductive agent include graphite, such as natural graphite and artificial graphite; carbon-based materials, such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black, and carbon fiber; metal powders, such as copper powder, nickel powder, aluminum powder, and silver powder, or metal fibers; conductive whiskers, such as zinc oxide whiskers and potassium titanate whiskers; conductive metal oxides, such as titanium oxide; or conductive polymers, such as polyphenylene derivatives, and any one of these can be used alone or as a mixture of two or more thereof.

[0039] In addition, when the used battery includes a used negative electrode, the used negative electrode includes a copper current collector and a negative electrode active material layer disposed on the copper current collector. The negative electrode active material layer may optionally include a binder or a conductive agent as well as the negative electrode active material. In this case, the binder or conductive agent included in the negative electrode active material layer is the same as that described above for the positive electrode.

[0040] A compound capable of reversibly intercalating and deintercalating lithium can be used as the negative electrode active material. Specific examples of the negative electrode active material may be carbonaceous materials such as artificial graphite, natural graphite, graphitized carbon fibers, and amorphous carbon; or composite materials including metal materials and carbonaceous materials such as Si-C composite materials or Sn-C composite materials, and any one of these or a mixture of two or more thereof may be used.

[0041] If the used batteries are secondary batteries discarded after use, they may contain an electrolyte solution. If the electrolyte solution is included in the used batteries, the steps of removing the electrolyte solution from the used batteries and deactivating the batteries may be performed during the preparation of the used batteries. The electrolyte solution removal and battery deactivation steps can be performed, for example, by punching or cutting the used batteries and then storing them in salt water. However, these steps are not mandatory and are unnecessary for waste electrodes or used batteries that do not contain an electrolyte solution.

[0042] When the waste batteries are prepared through the above process, a shredding process (S20) may be performed if necessary. The shredding process may be performed by shredding (roughly grinding) the waste batteries to a size of several tens to several hundred millimeters. The shredding process is not essential, but when the shredding process is performed, the waste batteries can be pulverized more smoothly due to the increase in the reaction zone during the heat treatment process.

[0043] Subsequently, the waste battery is subjected to a heat treatment (S30). The heat treatment is performed at a temperature of 650°C or higher in an air atmosphere or an oxidizing atmosphere. When the heat treatment is performed within the above-mentioned atmosphere and temperature range, the aluminum current collector included in the waste positive electrode is converted into aluminum oxide (Al2O3) when melted.

[0044] In this case, the heat treatment atmosphere may specifically be an air atmosphere or an oxygen atmosphere containing 21 mol% to 99 mol% of oxygen. When the heat treatment is performed in an inert atmosphere other than air or an oxidizing atmosphere or in a vacuum, aluminum does not undergo oxidation reaction even when the heat treatment is performed at a temperature of 650°C or higher, and thus conversion to aluminum oxide does not occur.

[0045] The heat treatment temperature may be in the range of 650°C or higher, for example, 650°C to 1080°C. When waste batteries are heat treated at temperatures above 650°C, the aluminum current collector is converted to aluminum oxide while being melted. This change in composition causes the aluminum current collector to pulverize. Furthermore, when the heat treatment temperature falls within the above range, the binder included in the positive electrode active material layer vaporizes during the heat treatment, reducing the bonding force between the positive electrode active material particles and thus causing the positive electrode active material layer to pulverize.

[0046] When the heat treatment temperature is lower than 650°C, since not all of the aluminum present on the surface of the aluminum current collector is converted into aluminum oxide, but only a part of it is converted into aluminum oxide, the aluminum current collector remains in a plate shape without being pulverized. In the case of waste batteries including waste negative electrodes, the heat treatment can be carried out at a temperature below 1,080°C (the melting temperature of the copper current collector). The reason for this is that when the heat treatment temperature is higher than the melting temperature of the copper current collector, impurities may be generated due to the introduction of copper since the copper current collector is melted during the heat treatment. In the case of impurities generated by the introduction of copper, a refining process for removing copper may be required, during which valuable metals may be lost, thereby reducing the recovery rate.

[0047] In addition, in the method of the present invention, although not required, if the used battery includes a used negative electrode, a step of removing carbon from the negative electrode active material layer of the used negative electrode can be further performed. Specifically, the step of removing carbon from the negative electrode active material layer can be performed by heat treating the used battery at a temperature of 250°C to 500°C.

[0048] For example, before the heat treatment at a temperature of 650°C or above, the waste battery may be subjected to a preliminary heat treatment at a temperature of 200°C to 500°C to remove carbon.

[0049] In addition, the step of removing carbon may be performed by a method in which heat treatment at a temperature of 650° C. or higher is performed by a multi-stage heating method.

[0050] In this case, the preliminary heat treatment can be performed at a temperature below 650°C, for example, 250°C to 500°C, and can be performed in an oxidizing atmosphere or an air atmosphere. Multi-stage heating can, for example, include: after the waste batteries are preliminarily heated to a temperature range of 250°C to 500°C and maintained at this temperature for a certain period of time for heat treatment, the waste batteries are secondary heated to a temperature above 650°C for heat treatment. As described above, when the preliminary heat treatment or multi-stage heating is performed, the carbon in the negative electrode active material layer reacts with oxygen, converting into carbon monoxide or carbon dioxide, and being discharged in a gaseous state. When the heat treatment temperature in the carbon removal step falls within the above range, the phenomenon of excessive localized heat generation due to the reaction of carbon and oxygen can be prevented, and the carbon in the negative electrode active material layer can be effectively removed.

[0051] Heat treatment can be performed, for example, by placing the waste batteries into a heat treatment furnace equipped with a heat source and then heating them. Any heat treatment furnace can be used without particular limitation, as long as it has space for the waste batteries, includes a heat source inside or outside the heat treatment furnace, includes a feed channel on one side of the heat treatment furnace for feeding the waste batteries, and has a discharge portion for recovering the products after the reaction is completed, but can induce an oxidation reaction. For example, any of a muffle furnace, an open hearth furnace, and a rotary kiln can be used. In addition, a gas burner, a coal burner, a resistance heating element, or an infrared (IR) lamp can be used as the heat source, but the heat source is not limited thereto.

[0052] Next, aluminum oxide powder and positive electrode active material powder are recovered from the heat-treated waste batteries ( S40 ).

[0053] As described above, when the aluminum current collector is heat-treated at a temperature of 650°C or above in air or an oxidizing atmosphere, it is converted into aluminum oxide (Al2O3) while being melted, and the physical properties of the current collector, such as hardness and brittleness, are also changed due to such composition changes, and the converted aluminum oxide is converted into spherical fine particles. Since the binding force between the current collector particles converted into aluminum oxide particles is very weak, the current collector is easily pulverized even by a small impact. In addition, during the heat treatment process, the binder that binds the active material particles is desorbed from the current collector while being evaporated and pulverized. Therefore, according to the method of the present invention, even without a separate crushing device, aluminum oxide powder and positive electrode active material powder can be easily recovered from waste batteries that have been heat-treated.

[0054] In this case, the particle size of the alumina powder may be several millimeters or less, for example, 10 mm or less, preferably 5 mm or less, and more preferably about 0.1 mm to about 5 mm. If the particle size of the alumina powder exceeds the above range and is larger, the positive electrode active material powder may become hard due to being contained in the alumina powder. Furthermore, if the positive electrode active material is confined in the alumina powder, the recovery rate of the valuable metals may be reduced because the valuable metals may not be easily recovered during the leaching process using the acidic solution in the valuable metal recovery step described later.

[0055] In the method for treating waste batteries of the present invention, if necessary, a post-treatment for recovering valuable metals from the powder recovered through the above process may be further performed.

[0056] Specifically, by adding the recovered positive electrode active material powder and alumina powder into an acidic solution, a step of recovering valuable metals from the positive electrode active material powder may be further performed.

[0057] In this case, the acidic solution can be a strong acid solution, for example, a sulfuric acid solution or a nitric acid solution. When the positive electrode active material powder and the aluminum oxide powder are added to the acidic solution, the valuable metals in the positive electrode active material powder are leached into the acidic solution. However, since aluminum oxide forms a strong ionic bond with oxygen, it is not easily leached into the acidic solution, and most of the aluminum oxide is precipitated in the acidic solution in the form of residues. Therefore, most of the valuable metals in the positive electrode active material powder are leached into the acidic solution, while the amount of aluminum leached is significantly less. Therefore, valuable metals with a low impurity content can be recovered without going through a refining process for extracting aluminum from the leachate.

[0058] When the current collector and positive electrode active material layer are pulverized using conventional mechanical pulverization methods, the aluminum contained in the current collector will be included in the recovered powder, where the aluminum precipitates as a salt in an acidic solution with a pH of 4 or above. Therefore, conventionally, after dissolving the positive electrode active material powder in an acidic solution, the pH of the solution is generally adjusted to about 4 to about 6 to precipitate the aluminum, and a valuable metal leaching process is performed after removing the aluminum precipitate. However, this process is limited by the fact that not only aluminum but also some valuable metals in the positive electrode active material may co-precipitate and be lost, resulting in a reduced recovery rate of the ultimately recovered valuable metals. However, according to the method of the present invention, since the aluminum is converted into alumina powder, the amount of aluminum dissolved in the acidic solution is less than in conventional cases, and thus the aforementioned aluminum refining process can be omitted or minimized. Therefore, according to the method of the present invention, since the loss of valuable metals can be minimized, a high recovery rate of valuable metals can be achieved.

[0059] In the waste battery treatment method of the present invention, if necessary, a separate step of separating aluminum oxide from the acidic solution may also be performed. In this case, the aluminum oxide separation step may, for example, include separating the residual aluminum oxide from the acidic solution through filtration and washing. Performing this aluminum oxide separation step further reduces the amount of impurities in the leachate. More preferably, the step of separating the precipitated aluminum oxide is performed at the initial stage of valuable metal leaching.

[0060] Hereinafter, the present invention will be described in more detail based on specific embodiments.

[0061] Example 1

[0062] A positive electrode scrap having a positive electrode active material layer formed on an aluminum current collector was prepared, and then loaded into a heat treatment furnace and heat-treated at 650° C. in an air atmosphere.

[0063] Figure 3 The photo of the cathode waste before heat treatment is shown ( Figure 3 (a)) and a photograph showing the state after heat treatment ( Figure 3 (b)). Figure 3 , it can be confirmed that both the current collector and the positive electrode active material have been pulverized after heat treatment.

[0064] Comparative Example 1

[0065] A positive electrode scrap having a positive electrode active material layer formed on an aluminum current collector was prepared, and then loaded into a heat treatment furnace and heat-treated at 600° C. in an air atmosphere.

[0066] Figure 4 The photo of the cathode waste before heat treatment is shown ( Figure 4(a)) and a photograph showing the state after heat treatment ( Figure 4 (b)). Figure 4 , it can be confirmed that when heat-treated at 600°C, the positive electrode active material layer is pulverized and peeled off from the current collector, but the current collector still maintains its original plate shape.

Claims

1. A method for treating waste batteries, comprising: Preparing a used battery including a used positive electrode, wherein the used positive electrode includes an aluminum current collector and a positive electrode active material layer formed on at least one surface of the aluminum current collector; heat-treating the waste battery at a temperature of 650° C. or higher in an oxidizing atmosphere to convert the aluminum current collector into aluminum oxide powder, thereby pulverizing the aluminum current collector and the positive electrode active material without a pulverization process; Recovering aluminum oxide powder and positive electrode active material powder from thermally treated waste batteries; recovering valuable metals from the positive electrode active material powder by adding the recovered positive electrode active material powder and alumina powder to an acidic solution; and The method also includes separating the aluminum oxide powder from the acidic solution.

2. The method for treating waste batteries according to claim 1, wherein: The heat treatment is performed at 650°C to 1080°C.

3. The method for processing waste batteries according to claim 1, further comprising shredding the waste batteries before heat-treating the waste batteries.

4. The method for treating waste batteries according to claim 1, wherein: The oxidizing atmosphere is an atmosphere containing 21 mol % to 99 mol % of oxygen.

5. The method for treating waste batteries according to claim 4, wherein: The oxidizing atmosphere is an air atmosphere.

6. The method for treating waste batteries according to claim 1, wherein: The used batteries are batteries containing an electrolyte solution, and The preparation of the spent batteries includes removing electrolyte solution from the spent batteries and deactivating the batteries.

7. The method for treating waste batteries according to claim 1, wherein: The waste battery further comprises a waste negative electrode having a copper current collector. 8 . The method for treating waste batteries according to claim 7 , further comprising removing carbon from the negative electrode active material layer of the waste negative electrode.

9. The method for treating waste batteries according to claim 8, wherein: The carbon removal includes performing a preliminary heat treatment on the waste battery at a temperature of 250°C to 500°C.

10. The method for treating waste batteries according to claim 1, wherein: The heat treatment of the spent batteries at a temperature of 650° C. or higher is performed by a multi-stage heating method.

11. The method for treating waste batteries according to claim 10, wherein: The multi-stage heating includes performing heat treatment in the following manner: after preliminarily heating the waste batteries to a temperature range of 250° C. to 500° C. and maintaining the temperature for a certain period of time for heat treatment, the waste batteries are secondary heated to a temperature above 650° C.

12. The method for treating waste batteries according to claim 1, wherein: The particle size of the aluminum oxide powder recovered from heat-treated waste batteries is less than 10 mm.

13. The method for treating waste batteries according to claim 1, wherein: The separation of the aluminum oxide powder includes separating the aluminum oxide powder as a residue from the acidic solution through filtering and washing processes.

14. The method for treating waste batteries according to claim 1, wherein: The acidic solution contains at least one of sulfuric acid or hydrochloric acid.

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