Manufacturing method of battery material

Abstract

According to the present disclosure, it is possible to improve the efficiency of recovering a noble metal from a recovery target such as a used lithium ion secondary battery. A production method disclosed herein includes: a preparation step S11 for preparing a recovery target containing at least one of Ni and Co; a measurement step (S12) for measuring the amount of substance of the oxygen element and the reducing component contained in the object to be recovered; a determination step (S13) for determining whether or not the mass ratio of the reducing component to the oxygen element is equal to or greater than a threshold value based on the stoichiometric ratio of the oxide of the reducing component; a reducing component addition step (S14) for adding a reducing component to the object to be recovered when the determination result of the determination step is lower than a threshold value; and a heating step (S15) in which the object to be recovered is heated in an inert atmosphere. This makes it possible to reduce a noble metal such as Ni or Co to a metal elementary substance, and thus makes it possible to improve the recovery efficiency of the noble metal.

Description

Technical Field

[0001] The technology disclosed herein relates to methods for making battery materials. Background Art

[0002] Lithium-ion secondary batteries are widely used in various fields. The lithium-ion secondary batteries use various materials including precious metals such as Ni and Co. For example, lithium transition metal composite oxides such as lithium nickel composite oxide, lithium cobalt composite oxide, lithium nickel cobalt composite oxide, and lithium nickel cobalt manganese composite oxide are used as the positive electrode active material. In addition, aluminum is used as the positive electrode core. On the other hand, carbon materials are used as the negative electrode active material. Moreover, copper is used as the negative electrode core. In addition, aluminum is also used as the battery case that accommodates these electrodes.

[0003] In recent years, the development of recycling technology that recovers precious metals from used batteries, processing waste, etc. and reuses them as battery materials has been actively promoted. In this recycling technology, first, the recycling object (used batteries, processing waste, etc.) is roasted. Then, the roasted recycling object is subjected to acid leaching. In this way, a metal solution in which the metal components (Li, Ni, Co, Mn, Al, Cu, etc.) in the recycling object are dissolved in the acid solution can be obtained. In addition, the carbon component in the recycling object can be separated by this acid leaching. On the other hand, various separation treatments (neutralization precipitation, solvent extraction, etc.) are performed on the metal solution after acid leaching. In this way, the required metal components can be extracted and reused as battery materials.

[0004] An example of this recycling technology is disclosed in Patent Document 1. In the recycling method described in Patent Document 1, in a heating process (roasting process), a battery slag (recycling object) having a positive electrode active material containing Ni and / or Co and a negative electrode active material containing graphite is heated, thereby oxidizing the graphite contained in the negative electrode active material in the battery slag to generate carbon dioxide gas. Then, in this recycling method, the recycling object is roasted in an oxidizing atmosphere (for example, an atmospheric atmosphere). As a result, the precious metals (trivalent or tetravalent Ni ions and Co ions) in the recycling object are reduced to divalent oxides. In Patent Document 1, the view that such divalent oxides are easily dissolved in an acid solution in an acid leaching process is disclosed.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2022-118594 Summary of the invention

[0008] However, according to the research results of the present inventors, it is known that the solubility of the above-mentioned divalent oxides of the noble metals in the acid solution is still insufficient. Moreover, if the acid solubility of the noble metal is low, not only the noble metal but also many other metal materials (Cu, etc.) may be dissolved in the metal solution after acid leaching. As a result, not only the separation process for separating impurities is complicated, but also a part of the noble metal may be removed in the separation process.

[0009] In order to solve the above-mentioned problems, a method for producing a battery material having the following structure (hereinafter, also simply referred to as a “production method”) is provided.

[0010] The manufacturing method of the battery material disclosed in this article includes the following steps: a preparation step, preparing a recycling object containing at least one of Ni and Co; a measurement step, measuring the amount of oxygen element and reducing component contained in the recycling object; a judgment step, judging whether the amount ratio of the reducing component to the oxygen element is above a threshold value based on the stoichiometric ratio of the oxide of the reducing component; a reducing component adding step, when the judgment result of the judgment step is lower than the threshold value, adding the reducing component to the recycling object; and a heating step, heating the recycling object under an inactive atmosphere.

[0011] In the manufacturing method of the above structure, roasting is performed under the condition that a large amount of reducing components are present in the recycling object and oxygen is not supplied from the outside. As a result, the movement of oxygen from the oxide of the precious metal in the recycling object (hereinafter also referred to as "precious metal oxide") to the reducing component is rapidly promoted. As a result, the precious metal in the recycling object can be reduced to a state of a metal unit. Moreover, the metal unit of the precious metal has excellent acid solubility compared with other metal materials, so it can contribute to a significant improvement in the recovery efficiency of the precious metal. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a longitudinal cross-sectional view schematically showing the internal structure of a lithium-ion secondary battery.

[0013] Figure 2 It is schematically indicated Figure 1 A perspective view of an electrode body of a lithium-ion secondary battery shown.

[0014] Figure 3 This is a flowchart illustrating a method for producing a battery material according to one embodiment.

[0015] Figure 4 This is a flowchart illustrating in detail a calcination step in a production method according to one embodiment.

[0016] Figure 5 This is a flowchart illustrating in detail a solvent extraction step in a production method according to one embodiment.

[0017] Figure 6 It is a figure which shows the result of XRD analysis in the test example.

[0018] Explanation of symbols

[0019] 1Lithium-ion secondary battery

[0020] 10 Shell

[0021] 12 Positive terminal

[0022] 14 Negative terminal

[0023] 20 electrode body

[0024] 30 positive plate

[0025] 32 positive electrode core

[0026] 34 Positive electrode active material layer

[0027] 40 negative plate

[0028] 42 negative electrode core

[0029] 44 Negative electrode active material layer

[0030] 50 Isolators DETAILED DESCRIPTION

[0031] Hereinafter, the embodiments of the technology disclosed herein will be described with reference to the accompanying drawings. It should be noted that matters other than those specifically mentioned in this specification and matters required for the implementation of the technology disclosed herein can be grasped as design matters for those skilled in the art based on the prior art in this field. The technology disclosed herein can be implemented based on the contents disclosed in this specification and the technical common sense in this field.

[0032] 1. Recycling objects

[0033] The manufacturing method of the battery material involved in this embodiment manufactures the battery material (typically the material of the positive electrode active material of the lithium ion secondary battery, the precursor of the positive electrode active material, and the positive electrode active material) by recovering precious metals such as Ni and Co from the specified recycling object. As an example of the recycling object here, a used lithium ion secondary battery can be cited. The lithium ion secondary battery is described in detail below. Figure 1 It is a longitudinal cross-sectional view schematically showing the internal structure of a lithium-ion secondary battery. Figure 2 It is schematically indicated Figure 1 A perspective view of an electrode body of a lithium-ion secondary battery shown.

[0034] like Figure 1 As shown, the lithium ion secondary battery 1 includes a case 10 , an electrode body 20 , and an electrolyte (not shown).

[0035] (1) Housing

[0036] The housing 10 is a box-shaped container. The electrode body 20 and the electrolyte are contained in the housing 10. The housing 10 is made of, for example, a metal material having a certain strength (aluminum (Al) or the like). In addition, a positive terminal 12 and a negative terminal 14 are installed in the housing 10. The positive terminal 12 and the negative terminal 14 are connected to the electrode body 20 in the housing 10. Specifically, the positive terminal 12 is connected to the positive electrode plate 30 (see Figure 2 ) is connected. Aluminum (Al) or the like is used for the positive electrode terminal 12. On the other hand, the negative electrode terminal 14 is connected to the negative electrode plate 40 of the electrode body 20. Copper (Cu) or the like is used for the negative electrode terminal 14.

[0037] (2) Electrode body

[0038] The electrode body 20 is a power generation element of the lithium ion secondary battery 1. Figure 2 As shown, the electrode body 20 includes a positive electrode plate 30, a negative electrode plate 40 and a separator 50. Figure 2 The electrode body 20 shown is a wound electrode body. The wound electrode body is made by stacking a positive electrode plate 30, a negative electrode plate 40 and a separator 50 to form a long strip-shaped laminate, and then winding the laminate. The structure of the electrode body 20 is not particularly limited, and can be other structures that have been known to the public (laminated electrode body, etc.).

[0039] The positive electrode plate 30 includes: a positive electrode core 32 as a conductive metal foil, and a positive electrode active material layer 34 provided on the surface of the positive electrode core 32. The positive electrode core 32 uses aluminum (Al) or the like. In addition, the positive electrode active material layer 34 is a mixture layer containing a positive electrode active material, a conductive material, a binder, etc. The positive electrode active material is a lithium transition metal composite oxide containing at least one of nickel (Ni) and cobalt (Co). As an example of the lithium transition metal composite oxide, lithium nickel composite oxide, lithium cobalt composite oxide, lithium nickel manganese composite oxide, lithium manganese cobalt composite oxide, lithium nickel cobalt composite oxide, lithium nickel manganese cobalt composite oxide, etc. can be cited. According to the manufacturing method involved in this embodiment, Ni and / or Co can be efficiently recovered from the recycling object containing such a lithium transition metal composite oxide. In addition, as a conductive material, carbon materials such as acetylene black and graphite can be cited. In addition, as a binder, resin materials such as polyvinylidene fluoride (PVdF) can be cited.

[0040] On the other hand, the negative electrode plate 40 includes: a negative electrode core 42 which is a conductive metal foil, and a negative electrode active material layer 44 provided on the surface of the negative electrode core 42. Copper (Cu) or the like is used for the negative electrode core 42. In addition, the negative electrode active material layer 44 is a composite layer containing a negative electrode active material, a binder, a thickener, and the like. As an example of the negative electrode active material, carbon materials such as graphite, hard carbon, and soft carbon can be cited. In addition, as other examples of the negative electrode active material, lithium titanate (LTO), silicon carbide, a composite containing carbon and silicon, silicon oxide (SiO X ) etc. The details are described below, but according to the manufacturing method involved in this embodiment, even if a battery using such a non-carbon-based negative electrode active material is used as a recycling object, the recovery efficiency of precious metals can be appropriately improved. In addition, as a binder, a resin material such as styrene-butadiene rubber (SBR) can be cited. As a thickener, a resin material such as carboxymethyl cellulose (CMC) can be cited.

[0041] In addition, the separator 50 is an insulating sheet sandwiched between the positive electrode plate 30 and the negative electrode plate 40. The separator 50 uses, for example, a resin material such as polyethylene (PE), polypropylene (PP), polyester, cellulose, polyamide, etc. In addition, a heat-resistant layer containing an inorganic filler can be formed on the surface of the separator 50. Examples of the inorganic filler include inorganic oxides such as aluminum oxide, magnesium oxide, silicon oxide, and titanium oxide, nitrides such as aluminum nitride and silicon nitride, metal hydroxides such as calcium hydroxide, magnesium hydroxide, and aluminum hydroxide, and clay minerals such as mica, talc, boehmite, zeolite, apatite, and kaolin.

[0042] (3) Electrolytes

[0043] The electrolyte is present between the positive electrode plate 30 and the negative electrode plate 40. Thus, the charge carrier (Li ion) can be moved between the positive electrode plate 30 and the negative electrode plate 40. As an example of the electrolyte, a non-aqueous electrolyte, a gel electrolyte, etc. can be cited. It should be noted that the electrolyte can be used without particular limitation for an electrolyte that can be used in a lithium ion secondary battery, and the technology disclosed herein is not limited.

[0044] As an example of a recycling object in the manufacturing method involved in the present embodiment, a lithium-ion secondary battery 1 is described above. However, the manufacturing method disclosed herein is not limited to the method of using the lithium-ion secondary battery 1 of the above-mentioned structure as a recycling object. For example, at the manufacturing site of the lithium-ion secondary battery, a part of the positive plate is sometimes cut off when the electrode body is made. Since the part of the cut positive plate (processing waste) also contains Ni and Co, it can also become a recycling object of the manufacturing method disclosed herein. In addition, at the manufacturing site of the lithium-ion secondary battery, sometimes the electrode body after manufacture has some defects and cannot be used for products. Such an electrode body can also be a recycling object because it contains Ni and Co. That is, the recycling object of the manufacturing method disclosed herein only needs to contain at least one of Ni and Co, and is not limited to a specific structure.

[0045] 2. Manufacturing methods of battery materials

[0046] Hereinafter, a method for producing the battery material according to the present embodiment will be described. Figure 3 It is a flowchart explaining the manufacturing method involved in this embodiment. Figure 4 It is detailed description Figure 3 Flow chart of the roasting process in . Figure 5 It is detailed description Figure 3 Flowchart of the solvent extraction process in FIG.

[0047] like Figure 3 As shown, the manufacturing method of the battery material according to the present embodiment comprises a calcination step S10, a screening step S20, an acid leaching step S30, a neutralization precipitation step S40, a solvent extraction step S50, an NCM crystallization step S60, a Li crystallization step S70, and an active material generation step S80. Each step will be described below.

[0048] (1) Calcination Step S10

[0049] In this process, the recycling object is heated at a predetermined temperature. Thus, the liquid components (electrolyte, etc.) in the recycling object can be removed, and the resin components (binder, separator, etc.) can be carbonized. In addition, when the charged lithium-ion secondary battery 1 is used as the recycling object, the function as a battery can be stopped by performing the roasting process S10. Thus, the next process can be safely performed.

[0050] Here, if Figure 4 As shown, the roasting step S10 in this embodiment includes: a preparation step S11, a measurement step S12, a determination step S13, a reducing component adding step S14 and a heating step S15. Thus, the recovery efficiency of precious metals such as Co and Ni can be greatly improved. Specific description is given below.

[0051] (a) Preparation Step S11

[0052] In this process, a recycling object including at least one of Ni and Co is prepared. As described above, the "recycling object" in the technology disclosed herein is not limited to completed lithium-ion secondary batteries, but also includes processing waste, defective parts (electrode bodies, etc.). It should be noted that the details of the recycling object have been described, so repeated descriptions are omitted. It should be noted that according to the manufacturing method involved in this embodiment, in addition to the above-mentioned nickel (Ni) and cobalt (Co), manganese (Mn), lithium (Li), etc. can also be recycled (manufactured).

[0053] (b) Measurement step S12

[0054] In the measuring step S12, the amount of oxygen element (O) and the reducing component contained in the recycling object is measured. In this step, a part of the recycling object can be taken as a sample for measurement, and the oxygen element and the reducing component of the sample for measurement can be measured. In addition, this step can be implemented only when the type of recycling object is changed, and it can also be implemented for all the prepared recycling objects. Thus, the manufacturing efficiency can be improved.

[0055] It should be noted that the "reducing component" in this specification is not particularly limited as long as it is a component that can reduce Ni and Co in the heating process S15 described later. In the manufacturing method involved in this embodiment, carbon element (C) is used as a reducing component. From the perspective of being less prone to oxidation and more stable until the start of the heating process S15, carbon is particularly preferred as a reducing component. In addition, depending on the type of recycling object, various carbon materials (conductive materials, binders, negative electrode active materials, etc.) are sometimes included. By using these carbon materials as a supply source of reducing components, it can help reduce the cost required for the recovery of precious metals.

[0056] In addition, the method for measuring the amount of the reducing component (carbon element) in the recovery object is not particularly limited, and the known measurement method can be used without particular limitation. For example, as a method for measuring the amount of carbon element, thermogravimetric differential thermal analysis (TG-DTA), SEM-EDS analysis, combustion oxidation-non-dispersive infrared absorption method, combustion volume method, etc. can be cited.

[0057] Next, a method for determining the amount of oxygen element in the recycling object is described. First, when the chemical composition of the positive electrode active material in the recycling object is known in advance, the amount of metal element in the recycling object can be determined, and the amount of oxygen element can be calculated based on the amount of metal element. In this way, the amount of oxygen element in a precious metal oxide (for example, a lithium transition metal composite oxide) can be easily determined. A specific example of this measurement step is as follows. First, prepare a solution in which a part of the recycling object (the sample for measurement) is dissolved in an acid. Next, the solution is subjected to inductively coupled plasma mass spectrometry (ICP: Inductively Coupled Plasma). In this way, the total amount M of transition metal elements (Ni, Co, Mn) in the recycling object can be determined. Then, after the chemical composition of the positive electrode active material in the recycling object (LiNi x Co y Mn z O δ ), the ratio (x+y+z:δ) of the total amount of transition metal elements (x+y+z) to the amount of O (δ) can be determined. In this case, the amount of oxygen element N can be calculated from the ICP measurement result (the total amount of metal elements M) based on the following formula (1).

[0058] N=δ·M / (x+y+z) (1)

[0059] It should be noted that the method for determining the amount of oxygen in the recovered object is not limited to the above method, and a known determination method can be used without particular limitation. For example, the oxygen in the recovered object can be directly determined by SEM-EDS analysis, XRF analysis, etc. By using these methods, the amount of oxygen can be determined even when the chemical composition of the positive electrode active material in the recovered object is unknown.

[0060] (c) Determination step S13

[0061] In the determination step S13, it is determined whether the mass ratio of the reducing component to the oxygen element is above a predetermined threshold value. Here, the "threshold value" in this step is set based on the stoichiometric ratio of the oxide of the reducing component. For example, when carbon is used as the reducing component, the "oxide of the reducing component" becomes carbon dioxide (CO2). At this time, in the heating step S15 described later, in order to properly reduce the oxide of the precious metal, the threshold value is set to a value above the ratio of the carbon element to the oxygen element in CO2 (1 / 2). Then, in this step, it is determined whether the mass ratio (C / O ratio) of the carbon element (reducing component) to the oxygen element in the recovery object is above 1 / 2. In this way, it is possible to determine whether there is a reducing component in the recovery object that is sufficient to reduce the precious metal to a metal element. Then, when the C / O ratio is above 1 / 2 ( Figure 4 On the other hand, when the C / O ratio is less than 1 / 2 ( Figure 4 If the result of step S13 is No, the recovered object is provided to the reducing component adding step S14.

[0062] It should be noted that, as described above, the threshold value in this process can be set to a value greater than the stoichiometric ratio of the oxide of the reducing component. For example, when the reducing component is carbon, the threshold value can be set to 3 / 4 or more (more preferably 1 or more, further preferably 5 / 4 or more, and particularly preferably 3 / 2 or more). Thus, only the recovery object containing a large amount of reducing component (carbon element) can be supplied to the heating process S15, so the reduction of the precious metal oxide in the heating process S15 can be further promoted.

[0063] (d) Reducing Component Adding Step S14

[0064] In the reducing component adding step S14, when the determination result of the determination step S13 is lower than the threshold value ( Figure 4 In the case of a no in S13 of the determination step S13), a reducing component is added to the recycling object. In the present embodiment, for the recycling object whose C / O ratio is determined to be less than 1 / 2 in the determination step S13, a reducing component (carbon-containing material) is added in such a way that the C / O ratio becomes above a threshold value (above 1 / 2). As a result, it is possible to make the recycling object contain a reducing component (carbon element) sufficient to reduce the precious metal to a metal element. It should be noted that as the carbon-containing material here, carbon materials such as graphite, hard carbon, and soft carbon can be cited. In addition, the carbon-containing material can be a resin material such as polyolefins and polyesters. These resin materials produce carbon elements due to the initial carbonization in the heating step S15, and therefore can be used as a supply source of carbon elements.

[0065] It should be noted that in this process, a reducing component in an amount far exceeding the above threshold value may be added. For example, when the reducing component is carbon, the carbon-containing material may be added in such a manner that the C / O ratio in the recovery object becomes 3 / 4 or more (more preferably 1 or more, further preferably 5 / 4 or more, and particularly preferably 3 / 2 or more). Thus, the recovery object containing a large amount of reducing components (carbon elements) can be supplied to the heating process S15, thereby further promoting the reduction of the precious metal oxide in the heating process S15.

[0066] (e) Heating step S15

[0067] In the heating process S15, the recovery object is heated under an inert atmosphere. Here, in the manufacturing method involved in the present embodiment, the recovery object whose mass ratio of the reducing component to the oxygen element is adjusted to be greater than the stoichiometric ratio of the oxide of the reducing component is supplied to the heating process S15. That is, the recovery object in the present embodiment is heated in the presence of a large amount of reducing components. Moreover, the heating process S15 in the present embodiment heats the recovery object under an inert atmosphere. Thus, it is possible to prevent the oxygen element from being supplied to the recovery object being heated. As a result, it is possible to promote the rapid movement of the oxygen element from the precious metal oxide (lithium transition metal composite oxide, etc.) to the reducing component. For example, when carbon element is used as the reducing component, a reaction as shown in the following formula (2) occurs. Thus, the precious metal in the recovery object can be reduced to a state of a metal element (metal Ni, metal Co).

[0068] LiNi x Co y Mn z O δ +C 1 / 2δ =Li+xNi+yCo+zMn+1 / 2δ·CO2 (2)

[0069] It should be noted that the heating temperature in this process is preferably 600°C or more, more preferably 650°C or more, further preferably 700°C or more, and particularly preferably 750°C or more. As the heating temperature increases, there is a tendency for the metal element of the noble metal to be easily generated. On the other hand, from the viewpoint of the reduction of the noble metal, the upper limit of the heating temperature is not particularly limited, and may be 1500°C or less, 1400°C or less, or 1300°C or less. It should be noted that from the perspective of reducing the cost required for the heat treatment, the upper limit of the heating temperature is preferably 1200°C or less, more preferably 1100°C or less, and particularly preferably 1000°C or less.

[0070] In addition, in this process, it is preferred to heat the recovery object under the circulation of an inert gas such as argon or nitrogen. In this way, the supply of oxygen to the recovery object can be appropriately prevented, further promoting the rapid reduction of the precious metal. It should be noted that the "inert atmosphere" in this specification refers to a heating atmosphere containing the above-mentioned inert gas as the main component. In other words, the heating atmosphere in this process is not limited to a completely inert atmosphere in which the content of the inert gas is 100% (the content of the oxygen element is 0%), but may contain a very small amount of oxygen element. Specifically, in the heating atmosphere in this process, the content of the oxygen element may be 5% or less (preferably 3% or less, more preferably 1% or less, further preferably 0.5% or less, and particularly preferably 0.1% or less). If it is such a small amount, even if the oxygen element is contained in the heating atmosphere, the precious metal in the recovery object can be reduced to a metal element.

[0071] (2) Screening step S20

[0072] like Figure 3 As shown, the manufacturing method involved in this embodiment implements a screening step S20 after implementing the roasting step S10. In this step, the various components contained in the recycling object after roasting are screened with a sieve. For example, when the processing waste of the positive electrode plate 30 is the recycling object, the positive electrode core 32 can be screened from the processing waste with a sieve and removed from the recycling object. In addition, when the electrode body 20 is the recycling object, in addition to the positive electrode core 32, the negative electrode plate 40 can also be removed from the recycling object. In addition, when the lithium-ion secondary battery 1 is the recycling object, in addition to the above-mentioned positive electrode core 32 and negative electrode plate 40, the shell 10 can also be removed from the recycling object. As a result, the content of impurities (Al, Cu, etc.) in the recycling object is reduced, which can help improve the recovery efficiency of precious metals (Co, Ni).

[0073] It should be noted that in this process, the recycling object can be crushed as needed. This can improve the efficiency of screening each component. For example, when the lithium-ion secondary battery 1 is the recycling object, the shell 10 and the electrode body 20 can be crushed. This makes it easy to remove the shell 10, the positive electrode core 32 and the negative electrode plate 40 from the recycling object.

[0074] In addition, the screening step S20 is not a step for intentionally completely removing impurities such as Al and Cu from the recycling object. The details are described below. Even if impurities remain in the recycling object, they can be fully removed in the following steps (acid leaching step S30, neutralization precipitation step S40, etc.). That is, this step can be appropriately omitted as needed. For example, when the recycling object has a low impurity content (processing waste of the positive plate 30, etc.), even if this step is omitted, precious metals can be efficiently recovered.

[0075] (3) Acid leaching step S30

[0076] Next, in the acid leaching process S30, the recovery object after the heating process S15 (screening process S20) is immersed in an acid solution. Thus, the precious metals (Li, Ni, Co, Mn) in the recovery object are dissolved in the acid solution. It should be noted that in this process, in addition to precious metals, other metal materials (Cu, Al, etc.) are sometimes dissolved in the acid solution. That is, the solution (metal solution) after acid leaching sometimes contains metal elements such as Li, Al, Cu, Co, Ni, and Mn. It should be noted that the acid leaching step can adopt the steps that have always been known without special restrictions. As an example, the pH of the acid solution used in this process is preferably -1.5 to 1.5 (more preferably -0.5 to 0.5). Thus, the metal components in the recovery object can be appropriately dissolved. It should be noted that as specific examples of acid solutions, inorganic acids such as sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid, and organic acids such as citric acid, ascorbic acid, oxalic acid, and acetic acid can be cited. In addition, in this process, it is preferred to filter the metal solution after acid leaching. Thus, undissolved components (carbon components, etc.) can be removed efficiently. It should be noted that the temperature of the acid solution is preferably 50°C or higher (more preferably 55°C or higher, particularly preferably 60°C or higher). Thus, the acid leaching step S30 can be shortened. In addition, the upper limit of the temperature of the acid solution is not particularly limited, and may be 90°C or lower, 85°C or lower, or 80°C or lower.

[0077] Here, in the existing recovery technology, the recovery object after roasting contains a large amount of precious metal oxides (nickel (II) oxide, cobalt (II) oxide, etc.). Therefore, in the existing acid leaching process, it is necessary to set conditions that can properly dissolve these oxides. However, if the acid leaching process is carried out under conditions that can dissolve the oxides of precious metals, metal materials other than precious metals (Cu, etc.) may also be dissolved in the acid solution in large quantities. In this case, a large amount of impurities will be mixed into the metal solution after the acid leaching process, so there will be problems such as complication of separation treatment and reduction of the recovery rate of precious metals. In contrast, in the manufacturing method involved in the present embodiment, the precious metal is reduced to a state of a metal element (metal nickel, metal cobalt, etc.) in the roasting process S10. The acid solubility of these metal elements is higher than that of other metal materials. Therefore, in the acid leaching process S30 in the present embodiment, the precious metal can be properly dissolved before Cu dissolves.

[0078] (4) Neutralization precipitation step S40

[0079] In this process, a neutralizing agent is added to the metal solution obtained in the acid leaching process S30. As a result, Al hydroxide (Al(OH)3) is precipitated and precipitated. As a result, Al can be roughly removed from the metal solution containing Li, Al, Cu, Co, Ni, Mn, etc. It should be noted that as a neutralizing agent used in this process, an alkaline solution with a pH of 11 to 15 (preferably pH 12 to 14) can be used. It should be noted that specific examples of neutralizing agents include aqueous sodium hydroxide solution, calcium hydroxide, ammonia, etc. In addition, in this process, it is also preferred to filter the metal solution after Al(OH)3 precipitation. As a result, Al(OH)3 can be efficiently removed from the metal solution.

[0080] (5) Solvent extraction step S50

[0081] In this process, Co, Ni, and Mn are extracted from the metal solution by solvent extraction. Thus, Co solution, Ni solution, and Mn solution can be prepared respectively. In addition, in this process, impurities (such as Al) remaining in the metal solution can also be separated. Specifically, Figure 5 As shown, the solvent extraction step S50 in this embodiment includes a Mn extraction step S51, a Co extraction step S52, and a Ni extraction step S53.

[0082] (a) Mn extraction step S51

[0083] In this process, an organic solvent (first extracting solution) having high extractability for Mn and low extractability for Li, Al, Cu, Co, and Ni is added to the metal solution. As the first extracting solution, a phosphate-based extracting agent, an oxime-based extracting agent, and the like can be used. Specific examples of phosphate-based extracting agents include di-2-ethylhexyl phosphate (D2EHPA), and the like. In addition, specific examples of oxime-based extracting agents include 2-hydroxy-5-nonylacetophenone oxime (LIX84), 5-dodecyl salicylaldehyde oxime (LIX860), and 5-nonyl salicylaldehyde oxime (ACORGAM5640), and the like. In addition, the first extracting solution can use a liquid obtained by mixing and diluting these extracting agents. Then, in this process, the metal solution and the first extracting solution are stirred to suspend them. As a result, the Mn in the metal solution is dissolved in the first extracting solution. Then, by leaving the solution to stand until the two liquids separate, a Mn solution in which Mn is dissolved in the first extract and a metal solution from which Mn has been removed can be obtained.

[0084] In addition, in this process, the Mn solution after extraction (the first extract containing Mn) can be subjected to a reverse extraction treatment. In the reverse extraction treatment, first, the Mn solution (organic phase) and the acidic aqueous solution are stirred and mixed using a stirrer or the like. Then, the mixture is allowed to stand until the two liquids are separated. Thus, an aqueous Mn solution in which Mn is dissolved in the acidic aqueous solution can be obtained. It should be noted that examples of the acidic aqueous solution used in the reverse extraction treatment include sulfuric acid, hydrochloric acid, and the like (particularly sulfuric acid).

[0085] (b) Co extraction step S52

[0086] In this process, an organic solvent (second extracting solution) with high extractability for Co and low extractability for Li, Al, Cu, and Ni is added to the metal solution. In this way, Co can be separated from the metal solution, and a Co solution in which Co is dissolved in the second extracting solution can be obtained. It should be noted that as a specific example of the second extracting solution, phosphonates such as 2-ethylhexylphosphonate (PC-88A) and the like can be cited. In addition, the extracted Co solution (the second extracting solution containing Co) can be subjected to a reverse extraction treatment. In this way, an aqueous Co solution can be obtained. It should be noted that the steps of the reverse extraction treatment have been described, so repeated records are omitted.

[0087] (c) Ni extraction step S53

[0088] In this process, an organic solvent (third extract) with high Ni extraction and low Li, Al, and Cu extraction is added to the metal solution. In this way, Ni can be separated from the metal solution, and a Ni solution in which Ni is dissolved in the third extract can be obtained. It should be noted that as a specific example of the third extract, carboxylic acid extractants such as neodecanoic acid and cyclohexane acid can be cited. In addition, the extracted Ni solution (the third extract containing Ni) can also be subjected to reverse extraction treatment. In this way, an aqueous Ni solution can be obtained. It should be noted that the steps of the reverse extraction treatment have been described, so repeated records are omitted.

[0089] (6) NCM crystallization step S60

[0090] In this process, crystals of metal compounds are precipitated from Co solution, Ni solution and Mn solution, respectively. In this process, the crystallization treatment known to the public can be adopted without particular limitation. For example, when the reverse extraction treatment is respectively implemented in Mn extraction process S51 to Ni extraction process S53, an aqueous mixed solution of Co solution, Ni solution and Mn solution is prepared. Then, the pH of the mixed solution is controlled to be alkaline. Thus, crystals of metal compounds can be precipitated. It should be noted that in the preparation of the mixed solution, the mixing ratios of the Co solution, Ni solution and Mn solution can be changed as needed. Then, in the adjustment of pH, the mixed solution is added dropwise to the reaction tank together with the alkaline solution (ammonia water, sodium hydroxide aqueous solution). Thus, spherical NiCoMn hydroxide (NCM precursor) can be crystallized.

[0091] (7) Li crystallization step S70

[0092] In the Li crystallization step S70, crystals of Li compounds are precipitated from the metal solution after the solvent extraction step S50. In this step, the crystallization treatment known to the public can be adopted without particular limitation. For example, in this step, sodium carbonate can be added to the metal solution. Thus, crystals of lithium carbonate (Li2CO3) can be precipitated. It should be noted that the Li compound generated in this step is not limited to lithium carbonate. For example, lithium hydroxide (LiOH) can be generated as a Li compound as needed. In the generation of the lithium hydroxide, first, the lithium carbonate precipitated from the metal solution is dissolved (or suspended) in a prescribed solvent. Then, calcium hydroxide is added to the solution. Thereafter, the solvent is evaporated and removed as needed. Thus, crystals of lithium hydroxide can be precipitated.

[0093] (8) Active Material Generation Step S80

[0094] In this step, the metal compound obtained in the NCM crystallization step S60 and the Li compound obtained in the Li crystallization step S70 are used to generate a battery material (positive electrode active material). Specifically, NiCoMn hydroxide (NCM precursor) and a Li compound (Li2CO3, etc.) are mixed and calcined. Thus, a positive electrode active material (lithium transition metal composite oxide) of a lithium ion secondary battery can be manufactured.

[0095] The above is a description of the manufacturing method of the battery material involved in the present embodiment. As described above, in the manufacturing method involved in the present embodiment, the roasting step S10 is implemented under the condition that there are a large amount of reducing components in the recycling object and the oxygen element is not supplied from the outside. As a result, the oxide of the precious metal in the recycling object is rapidly reduced to the state of the metal element. Since the metal element of the precious metal has high acid solubility, it can be easily dissolved in the acid solution before impurities such as Cu are dissolved in the acid leaching step S30. As a result, impurities in the metal solution can be reduced, which helps to improve the recovery rate of precious metals such as Co and Ni.

[0096] 3. Other Implementation Methods

[0097] An embodiment of the technology disclosed herein has been described above. It should be noted that the technology disclosed herein is not limited to the above-described embodiment, and also includes other embodiments in which various configurations are changed. Other examples of the embodiments of the technology disclosed herein will be described below.

[0098] (1) Processes after the calcination process

[0099] In the manufacturing method involved in the above-mentioned embodiment, after the roasting step S10 is implemented, the screening step S20 to the active material generation step S80 are implemented. However, the description of the above-mentioned embodiment is not intended to limit the steps after the roasting step. That is, in the manufacturing method disclosed herein, the steps after the roasting step can be appropriately added, deleted, or changed as needed.

[0100] (a) Omission of solvent extraction step

[0101] For example, according to the manufacturing method disclosed in this article, the solvent extraction step S50 can also be omitted. Specifically, as described above, in the technology disclosed in this article, the dissolution of Cu in the acid leaching step S30 can be suppressed. Therefore, the metal solution after acid leaching mainly contains Li, Al, Ni, Co, and Mn. If Li is recovered separately on the basis of properly separating Al from such a metal solution, a solution containing precious metals (Ni, Co, Mn) with high purity can be obtained. In this case, even if the solvent extraction step S50 is not implemented, a mixed solution of precious metals used in the NCM crystallization step S60 can be obtained. It should be noted that Al can be fully separated from the metal solution by the above-mentioned neutralization precipitation step S40. On the other hand, as an example of a method for recovering Li, the following method can be cited. First, when implementing the roasting step S10, a non-metallic chlorine compound (HCl, etc.) is added to the recovery object for roasting. As a result, the Li in the recovery object reacts with the non-metallic chlorine compound to generate LiCl. Next, a water immersion step is implemented to immerse the roasted recovery object in water. Since LiCl is a water-soluble compound, Li can be recovered simply by bringing the recovery target into contact with water.

[0102] (b) Changes in the solvent extraction process

[0103] In addition, the specific processing steps in the solvent extraction process S50 can be appropriately changed. For example, the solvent extraction process S50 in the above-mentioned embodiment includes a Mn extraction process S51, a Co extraction process S52, and a Ni extraction process S53. Thus, Co solution, Ni solution, and Mn solution can be extracted independently. However, multiple precious metals can also be extracted simultaneously in the solvent extraction process S50. For example, an organic solvent with high extractability for Ni and Co and low extractability for Li, Al, and Cu can be added to the metal solution after Mn extraction. Thus, Ni and Co can be extracted simultaneously. If multiple precious metals are extracted simultaneously in this way, it is possible to achieve an improvement in manufacturing efficiency brought about by shortening the process.

[0104] (c) Addition of Li separation step

[0105] In addition, the Li separation process can be performed on the metal solution after the solvent extraction process S50. Specifically, the metal solution after the solvent extraction process S50 contains Li as the main component. However, in addition to Li, the metal solution also contains Cu that cannot be removed in the acid leaching process S30, Al that cannot be removed in the neutralization precipitation process S40, etc. The Li separation process is a process for removing Cu and Al from the metal solution. As a result, a high-purity Li compound can be obtained in the Li crystallization process S70. It should be noted that the method for preparing the Li solution is not particularly limited, and it is preferred to appropriately adopt a solvent extraction method, an ion exchange method, or other methods that have been known to the public.

[0106] (d) Addition of Li Concentration Step

[0107] In addition, a Li concentration process can be performed on the metal solution after the above-mentioned Li separation process. In the Li concentration process, the Li solution is heated to evaporate the solvent. As a result, a high-concentration Li solution can be obtained, thereby improving the crystallization efficiency in the Li crystallization process S70. It should be noted that the Li concentration process can be performed on a metal solution that has not undergone a Li separation process. For example, when impurities (Cu, Al) are fully removed between the acid leaching process S30 and the solvent extraction process S50, the Li separation process can be omitted and only the Li concentration process can be performed. In this case, a high-concentration Li solution can also be obtained.

[0108] (e) Changes in the NCM crystallization process

[0109] In addition, in the above-mentioned embodiment, the NCM crystallization step S60 is implemented on the mixed solution formed by mixing the Co solution, the Ni solution and the Mn solution. As a result, the NiCoMn hydroxide, which is a metal compound containing Co, Ni and Mn, can be crystallized. However, in the NCM crystallization step, the metal compound can be crystallized independently from the Co solution, the Ni solution and the Mn solution. In the case of reverse extraction with sulfuric acid as in the above-mentioned embodiment, the crystals of manganese sulfate (MnSO4) can be precipitated from the Mn solution by removing the solvent and cooling as needed. In addition, crystals of cobalt sulfate (CoSO4) are precipitated from the Co solution. Moreover, crystals of nickel sulfate (NiSO4) are precipitated from the Ni solution. The battery material (positive electrode active material) can be generated by mixing the NCM precursor synthesized from the crystals of these sulfates with a Li compound and calcining it.

[0110] (2) Reducing ingredients used in the calcination process

[0111] In addition, the detailed conditions in the roasting process S10 can also be appropriately changed. For example, in the manufacturing method involved in the above-mentioned embodiment, carbon element is used as a reducing component. However, as mentioned above, the reducing component is not particularly limited as long as it is a component that can reduce Ni and Co in the heating process. As reducing components other than carbon element (C), lithium (Li), cesium (Cs), potassium (K), barium (Ba), strontium (Sr), calcium (Ca), sodium (Na), magnesium (Mg), aluminum (Al), titanium (Ti), zirconium (Zr), manganese (Mn) and other metal-based reducing components can be cited. These metal-based reducing components are preferably present in the recovery object in the state of sulfite or the like. For example, if calcium sulfite (CaSO3) is used as a reducing component, the precious metal is reduced to a metal element in the heating process, and calcium oxide (CaO) is generated at the same time. In this case, the threshold value in the judgment process is set to a value above the stoichiometric ratio (1 / 1) of CaO. Thus, the precious metal in the recovery object can be appropriately reduced to a state of a metal element. It should be noted that in the determination step S12, as a method for determining the reducing component of the metal system, ICP, SEM-EDS analysis, XRF analysis, etc. can be cited. In addition, the reducing component as the determination object in the determination step S13 and the reducing component added in the reducing component adding step S14 can be the same or different. For example, when it is determined that the carbon element (C) is insufficient in the determination step S13, calcium sulfite (CaSO3) can be added in the reducing component adding step S14. Even in this case, the precious metal can be appropriately reduced to the state of the metal element in the heating step S15.

[0112] [Test example]

[0113] Hereinafter, test examples related to the technology disclosed herein will be described. It should be noted that the contents of the test examples described below are not intended to limit the technology disclosed herein.

[0114] 1. Sample Preparation

[0115] (Example 1)

[0116] In this experiment, a mixture of positive and negative plates was used as the recycling object, and a roasting process was performed on the recycling object. Specifically, as the positive plate, a positive electrode core (Al foil) was coated with a positive electrode active material layer. It should be noted that the positive electrode active material in this experiment was lithium nickel cobalt manganese composite oxide (LiNi 1 / 3 Co 1 / 3 Mn 1 / 3O2). On the other hand, as the negative electrode plate, a material obtained by coating a negative electrode active material layer on the surface of a negative electrode core (Cu foil) is used. In addition, a carbon material (graphite) is used as the negative electrode active material. Then, the mixture of the positive electrode plate and the negative electrode plate is crushed, and the powder that passes through a sieve with an aperture of 500 μm is used as a test sample.

[0117] Next, a portion of the test sample was taken and dissolved in sulfuric acid. Then, ICP was performed on the solution to measure the total mass M of Ni, Co, and Mn. Then, based on the composition of the positive electrode active material (LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2), and the amount of twice the total amount M is taken as the amount N of oxygen element (N=2M). In addition, in this experiment, thermogravimetric differential thermal analysis (TG-DTA) was also performed on a part of the test samples. In this thermogravimetric differential thermal analysis, the test samples were heated in an atmosphere of 800°C. It should be noted that in this analysis, the heating rate from room temperature (20°C) to 800°C was set to 5°C / min. The amount of carbon in the test sample was thus determined. Next, it was investigated whether the measured amount ratio (C / O ratio) of carbon element to oxygen element was greater than the stoichiometric ratio (1 / 2) of CO2. As a result, in Example 1, the above C / O ratio was greater than 1 / 2.

[0118] Next, in Example 1, the test sample was calcined in an inert atmosphere. Specifically, the test sample was placed in an electric furnace, and the temperature in the furnace was raised to 600°C while supplying Ar gas. It should be noted that the heating rate at this time was set to 5°C / min. Then, the calcination was performed for 5 hours while maintaining the temperature in the furnace at 600°C. Thereafter, the temperature in the furnace was cooled to 50°C, and the test sample was recovered.

[0119] (Example 2~Example 8)

[0120] In Examples 2 to 8, at least one of the conditions of the heating temperature, the heating atmosphere, and the mass ratio (C / O) of the test sample was changed from Example 1. The conditions of each example are shown in Table 1. It should be noted that in Examples 2 to 8, except for the conditions shown in Table 1, the preparation and calcination steps of the test sample were carried out in the same manner as in Example 1.

[0121] 2. Evaluation test

[0122] (1) XRD analysis

[0123] The calcined test samples were subjected to X-ray diffraction (XRD) analysis using a Mo ray source to evaluate the state of the Ni element in the test samples. Figure 6(XRD diagram of example 3) shown, for the test sample after roasting, peaks are confirmed near 19 ° and near 20 ° respectively. Among these, the peak (NiO peak) from Ni oxide can be confirmed near 19 °. On the other hand, the peak (Ni peak) from the metal element can be confirmed near 20 °. Then, in this test, the peak intensity ratio (Ni / NiO) of Ni peak and NiO peak is calculated. Then, when the peak intensity ratio is less than 1, it is evaluated as a sample in which NiO predominates. On the other hand, when the peak intensity ratio is more than 1, it is evaluated as a sample in which Ni predominates. The results are shown in Table 1.

[0124] In addition, in the XRD analysis, the states of Ni and Co in the test samples were also evaluated. Specifically, in the above XRD diagram, the sample in which only the NiO peak is confirmed is regarded as "NiO accounts for the majority ("NiO" in Table 1)". In addition, when both the NiO peak and the Ni peak are confirmed, it is regarded as "NiO and Ni are mixed ("NiO+Ni" in Table 1)". Moreover, when only the Ni peak is confirmed, it is regarded as "Ni accounts for the majority ("Ni" in Table 1)". In addition, for the remaining metal elements (Co), the state in the test sample after roasting is analyzed according to the same steps as the above-mentioned Ni state evaluation. The results are shown in Table 1.

[0125] (2) Recovery rate of acid leaching

[0126] The calcined test samples were acid-leached, and the leaching rates of each metal element (Ni, Co, Cu) were calculated. Specifically, first, the calcined test samples were added to 1 mol / L sulfuric acid (H2SO4). Then, while the temperature of the acid solution was maintained at room temperature (25°C), the stirring treatment was continued at a stirring speed of 500 rpm for 6 hours. Next, after the dissolved metal solution was filtered, ICP was applied to the dissolved solution. The amount of each Ni, Co and Cu in the metal solution was thereby determined. Then, based on the following formula (3), the leaching rate of each metal element was calculated. It should be noted that the "amount of substance before acid leaching" in formula (3) is a value estimated by measuring the amount of substance per 1g through ICP analysis and multiplying it by the weight of the sample added to the acid.

[0127] Leaching rate = (amount of substance in metal solution / amount of substance before acid leaching) × 100 (3)

[0128] [Table 1]

[0129]

[0130] As shown in Table 1, in Example 6, the leaching rates of Ni and Co dropped significantly. It is believed that this is because the roasting was carried out in an atmospheric atmosphere, and as a result, most of the precious metals in the recovery object were oxidized, making it difficult to dissolve in the low-temperature acid solution of 25°C. On the other hand, compared with Example 6, the leaching rates of Ni and Co in Example 7 were greatly improved. Moreover, the sample of Example 7 was analyzed, and the results showed that most of the precious metals (Ni, Co) were reduced to the state of metal elements. It can be seen that roasting in a state where there is a large amount of reducing components (carbon) in the recovery object and no oxygen element is supplied from the outside can help improve the recovery rate of Ni and Co. In addition, by comparing Examples 1 to 3, Example 5, and Example 8, it was confirmed that as the heating temperature increases, the proportion of metal elements in the recovery object after roasting increases, and the leaching rate in acid leaching increases.

[0131] The above is a detailed description of the technology disclosed in this article, but these are only examples and do not limit the scope of protection claimed in the patent. The technology described in the scope of protection claimed in the patent includes various deformations and changes of the specific examples illustrated above. That is, the technology disclosed in this article includes the following items 1 to 8.

[0132] <Project 1>

[0133] A method for manufacturing a battery material, comprising the following steps:

[0134] A preparation step of preparing a recycling object including at least one of Ni and Co;

[0135] A measuring step of measuring the amount of oxygen and reducing components contained in the recovery object;

[0136] a determination step of determining whether the amount ratio of the reducing component to the oxygen element is equal to or greater than a threshold value based on a stoichiometric ratio of an oxide of the reducing component;

[0137] a reducing component adding step, when the determination result of the determination step is lower than the threshold value, adding the reducing component to the recycling object; and

[0138] The heating step is to heat the above-mentioned recovery object under an inert atmosphere.

[0139] <Project 2>

[0140] The method for producing a battery material according to Item 1, wherein the reducing component is carbon element, and the threshold value is a value greater than the stoichiometric ratio of CO 2 .

[0141] <Project 3>

[0142] The method for producing a battery material according to item 1 or 2, wherein in the heating step, the recycling object is heated at 650°C to 1000°C.

[0143] <Item 4>

[0144] The method for producing a battery material according to any one of items 1 to 3, wherein in the heating step, the recycling target is heated under an argon atmosphere or a nitrogen atmosphere.

[0145] <Item 5>

[0146] The method for producing a battery material according to any one of items 1 to 4, wherein in the measuring step, the amount of substance of the metal element in the recovery target is measured, and the amount of substance of the oxygen element is calculated based on the amount of substance of the metal element.

[0147] <Item 6>

[0148] A method for manufacturing a battery material according to any one of items 1 to 5, wherein the recycling object includes at least one selected from lithium nickel composite oxide, lithium cobalt composite oxide, lithium nickel manganese composite oxide, lithium manganese cobalt composite oxide, lithium nickel cobalt composite oxide, and lithium nickel manganese cobalt composite oxide.

[0149] <Item 7>

[0150] The method for producing a battery material according to any one of items 1 to 6, further comprising an acid leaching step of immersing the recovered object after the heating step in an acid solution.

Claims

1. A method for manufacturing a battery material, comprising the following steps: A preparation step of preparing a recycling object including at least one of Ni and Co; A measuring step of measuring the amount of oxygen and reducing components contained in the recovery object; a determination step of determining whether the amount ratio of the reducing component to the oxygen element is equal to or greater than a threshold value based on a stoichiometric ratio of an oxide of the reducing component; a reducing component adding step, when the determination result of the determination step is lower than the threshold value, adding the reducing component to the recycling object; as well as The heating step is to heat the recovery object in an inert atmosphere.

2. The method for producing a battery material according to claim 1, wherein: The reducing component is carbon element, and the threshold value is a value greater than the stoichiometric ratio of CO 2 .

3. The method for producing a battery material according to claim 1, wherein: The heating step is to heat the recycling object at 650°C to 1000°C.

4. The method for producing a battery material according to claim 1, wherein: The heating step is to heat the recovery object in an argon atmosphere or a nitrogen atmosphere.

5. The method for producing a battery material according to claim 1, wherein: The measuring step is to measure the amount of substance of the metal element in the recovery object, and calculate the amount of substance of the oxygen element based on the amount of substance of the metal element.

6. The method for producing a battery material according to claim 1, wherein: The recycling object includes at least one selected from lithium nickel composite oxide, lithium cobalt composite oxide, lithium nickel manganese composite oxide, lithium manganese cobalt composite oxide, lithium nickel cobalt composite oxide, and lithium nickel manganese cobalt composite oxide.

7. The method for producing a battery material according to any one of claims 1 to 6, wherein: Further including: The acid leaching step is to immerse the recovered object after the heating step in an acid solution.

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