Method for manufacturing battery material

Abstract

To provide a method for manufacturing a battery material in which the recovery rate of valuable metals is improved.SOLUTION: The method for manufacturing a battery material disclosed herein includes: a preparation step of preparing a recovery target containing at least one of Ni and Co; an acid leaching step of immersing the recovery target in an acid solution and obtaining an acid leachate; an ammine complex generation step of mixing an ammonia solution containing ammonium ions with the acid leachate to generate a metal solution containing an ammine complex of at least one of Ni and Co; and a solid-liquid separation step of obtaining the metal solution by a solid-liquid separation.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The technology disclosed herein relates to a method for producing battery materials. [Background technology]

[0002] Lithium ion secondary batteries are widely used in various fields. Various materials including valuable metals such as Ni and Co are used in these lithium ion secondary batteries. 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. Aluminum and the like are used as the positive electrode core.

[0003] In recent years, development of recovery technology has been promoted for recovering valuable metals from used batteries and process scraps and reusing them as battery materials. For example, Patent Document 1 discloses an example of a recovery technology for positive electrode plates. As disclosed in Patent Document 1, in the conventional recovery technology for positive electrode plates, the recovery target (lithium ion battery scrap) is leached with acid, and the leaching solution obtained by the leaching is neutralized to remove at least a part of the aluminum ions from the leaching solution to obtain a neutralized solution. Furthermore, the recovery method described in Patent Document 1 includes an extraction step in which the neutralized solution is subjected to solvent extraction to extract the remaining aluminum ions from the neutralized solution. It is disclosed that this allows cobalt (Co) and / or nickel (Ni) to be recovered from the extraction residue from which aluminum has been removed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-164971 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the higher the pH of the neutralization solution, the more the precipitation of aluminum advances, while some of the valuable metals (Ni and / or Co) also begin to precipitate as a precipitate. Therefore, in the conventional technology, the pH of the neutralization solution cannot be increased, and aluminum cannot be sufficiently removed from the neutralization solution. Therefore, the technology described in Patent Document 1 requires an extraction process to remove aluminum from the neutralization solution, which leads to a loss of valuable metals (Ni and / or Co) recovery due to the additional process.

[0006] The present disclosure has been made in view of the above circumstances, and has an object to provide a method for producing a battery material with an improved recovery rate of valuable metals (Ni and / or Co). [Means for solving the problem]

[0007] In order to solve the above problems, a method for producing a battery material (hereinafter, also simply referred to as a "production method") having the following configuration is provided.

[0008] The manufacturing method of a battery material disclosed herein includes a preparation step of preparing a recovery target containing at least one of Ni and Co, an acid leaching step of immersing the recovery target in an acid solution to obtain an acid leaching solution, an ammine complex formation step of mixing an ammonia solution containing ammonium ions with the acid leaching solution to generate a metal solution containing an ammine complex of at least one of the Ni and Co, and a solid-liquid separation step of obtaining the metal solution by solid-liquid separation.

[0009] In the manufacturing method having the above configuration, the acid leachate is subjected to an ammine complex formation step to obtain a metal solution containing an ammine complex of Ni and / or Co. This makes it possible to improve the recovery rate of valuable metals from the object to be recovered. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a vertical cross-sectional view that illustrates a schematic internal structure of a lithium-ion secondary battery. [Diagram 2]FIG. 2 is a perspective view that typically shows an electrode assembly of the lithium ion secondary battery shown in FIG. [Diagram 3] FIG. 3 is a flowchart illustrating the method for producing a battery material according to the first embodiment. [Figure 4] FIG. 4 is a flow chart for explaining in detail the preparation steps in FIG. [Diagram 5] FIG. 5 is a flowchart illustrating a method for producing a battery material according to the second embodiment. [Figure 6] FIG. 6 is a flow chart illustrating in detail the solvent extraction process according to the second embodiment. [Figure 7] FIG. 7 is a flowchart illustrating a method for producing a battery material according to the third embodiment. [Figure 8] FIG. 8 is a flowchart illustrating in detail the preparation process according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the technology disclosed herein will be described with reference to the drawings. Matters other than those specifically mentioned in this specification and necessary for implementing the technology disclosed herein can be understood as design matters for a person skilled in the art based on the prior art in the relevant field. The technology disclosed herein can be implemented based on the contents disclosed in this specification and the technical common sense in the relevant field. In addition, the expression "A to B" indicating a range in this specification includes the meaning of "A or more and B or less," as well as "preferably greater than A" and "preferably smaller than B."

[0012] 1. Items to be recalled The method for producing a battery material according to the present embodiment produces a battery material (typically, a material for a positive electrode active material of a lithium ion secondary battery, a precursor of the positive electrode active material, or a positive electrode active material) by recovering valuable metals such as Ni and Co from a predetermined recovery target. An example of the recovery target here is a used lithium ion secondary battery. Hereinafter, this lithium ion secondary battery will be specifically described. FIG. 1 is a vertical cross-sectional view that typically shows the internal structure of a lithium ion secondary battery. FIG. 2 is a perspective view that typically shows an electrode body of the lithium ion secondary battery shown in FIG. 1.

[0013] As shown in FIG. 1, the lithium ion secondary battery 1 includes a case 10, an electrode assembly 20, and an electrolyte (not shown).

[0014] (1) Case The case 10 is a box-shaped container. An electrode body 20 and an electrolyte are housed inside the case 10. For example, a metal material (such as aluminum (Al)) having a certain strength is used for the case 10. A positive electrode terminal 12 and a negative electrode terminal 14 are attached to the case 10. The positive electrode terminal 12 and the negative electrode terminal 14 are connected to the electrode body 20 inside the case 10. Specifically, the positive electrode terminal 12 is connected to a positive electrode plate 30 (see FIG. 2) of the electrode body 20. The positive electrode terminal 12 is made of aluminum (Al) or the like. On the other hand, the negative electrode terminal 14 is connected to a negative electrode plate 40 of the electrode body 20. The negative electrode terminal 14 is made of copper (Cu) or the like.

[0015] (2) Electrode body The electrode body 20 is a power generating element of the lithium ion secondary battery 1. As shown in Fig. 2, the electrode body 20 includes a positive electrode plate 30, a negative electrode plate 40, and a separator 50. The electrode body 20 shown in Fig. 2 is a wound electrode body. This wound electrode body is produced by stacking the positive electrode plate 30, the negative electrode plate 40, and the separator 50 to form a long strip-shaped laminate, and then winding the laminate. However, the structure of the electrode body 20 is not particularly limited, and may be any other conventionally known structure (such as a laminated electrode body).

[0016] The positive electrode plate 30 includes a positive electrode core 32, which is a metal foil having electrical conductivity, and a positive electrode active material layer 34 applied to the surface of the positive electrode core 32. Aluminum (Al) or the like is used for the positive electrode core 32. The positive electrode active material layer 34 is a composite layer containing a positive electrode active material, a conductive material, a binder, and the like. The positive electrode active material is a lithium transition metal composite oxide containing at least one of nickel (Ni) and cobalt (Co). Examples of such lithium transition metal composite oxides include 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. According to the manufacturing method of this embodiment, Ni and / or Co can be efficiently recovered from a recovery target containing such a lithium transition metal composite oxide. Examples of the conductive material include carbon materials such as acetylene black and graphite. Examples of the binder include resin materials such as polyvinylidene fluoride (PVdF).

[0017] On the other hand, the negative electrode plate 40 includes a negative electrode core 42, which is a metal foil having electrical conductivity, and a negative electrode active material layer 44 applied to the surface of the negative electrode core 42. The negative electrode core 42 is made of copper (Cu) or the like. The negative electrode active material layer 44 is a composite layer containing a negative electrode active material, a binder, a thickener, and the like. Examples of the negative electrode active material include carbon materials such as graphite, hard carbon, and soft carbon. Other examples of the negative electrode active material include lithium titanate (LTO), silicon carbide, a composite containing carbon and silicon, and silicon oxide (SiO X ) The binder may be a resin material such as styrene butadiene rubber (SBR). The thickener may be a resin material such as carboxymethyl cellulose (CMC).

[0018] The separator 50 is an insulating sheet interposed between the positive electrode plate 30 and the negative electrode plate 40. For example, a resin material such as polyethylene (PE), polypropylene (PP), polyester, cellulose, or polyamide is used for the separator 50. A heat-resistant layer containing an inorganic filler may be formed on the surface of the separator 50. Examples of such inorganic fillers 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.

[0019] (3) Electrolyte The electrolyte is present between the positive electrode plate 30 and the negative electrode plate 40. This allows charge carriers (Li ions) to move between the positive electrode plate 30 and the negative electrode plate 40. Examples of the electrolyte include a non-aqueous electrolyte solution and a gel electrolyte. Note that the electrolyte may be any electrolyte that can be used in a lithium ion secondary battery without any particular limitation, and does not limit the technology disclosed herein.

[0020] The lithium ion secondary battery 1 has been described above as an example of the object of collection in the manufacturing method according to the present embodiment. However, the manufacturing method disclosed herein is not limited to the method in which the lithium ion secondary battery 1 having the above-mentioned configuration is the object of collection. For example, at the manufacturing site of the lithium ion secondary battery, a part of the positive electrode plate may be cut off when the electrode body is manufactured. This cut part of the positive electrode plate (process waste material) may also contain Ni or Co, and therefore may be the object of collection in the manufacturing method disclosed herein. In addition, at the manufacturing site of the lithium ion secondary battery, some defect may occur in the electrode body after manufacture, and it may become unusable in the product. Such an electrode body may also be the object of collection because it may contain Ni or Co. In other words, the object of collection in the manufacturing method disclosed herein is not particularly limited to a specific structure as long as it contains at least one of Ni and Co as a valuable metal.

[0021] 2. Manufacturing method of battery materials The manufacturing method of the battery material according to this embodiment will be described below. Fig. 3 is a flow chart for explaining the manufacturing method according to the first embodiment. Fig. 4 is a flow chart for explaining in detail the preparation steps in Fig. 3.

[0022] <First embodiment> As shown in Fig. 3, the method for producing a battery material according to the first embodiment includes a preparation step S10, an acid leaching step S20, an ammine complex formation step S30, and a solid-liquid separation step S40. The method for producing a battery material disclosed herein may further include a precursor preparation step S50 and an active material formation step S60. The production method disclosed herein may further include other steps at any stage, and the remaining production process may be the same as that of a conventional method. Each step will be described below.

[0023] (1) Preparation process S10 In the preparation step S10, a recovery target containing at least one of Ni and Co as a valuable metal is prepared. Although not particularly limited, the preparation step S10 may include a recovery target preparation step S11, a heating step S12, and a sorting step S18 as shown in Fig. 4. The details will be described below.

[0024] (1-1) Recovery preparation process S11 In the recovery object preparation step S11, the recovery object is prepared. As described above, the "recovery object" in the technology disclosed herein may contain at least one of Ni and Co as a valuable metal. In other words, the recovery object is not limited to completed lithium ion secondary batteries, but also includes process waste materials and defective parts (electrode bodies, etc.). The details of the recovery object have already been described, so a duplicated description will be omitted.

[0025] (1-2) Heating process S12 In the heating step S12, the object to be collected is heated at a predetermined temperature. This allows liquid components (electrolyte, etc.) in the object to be collected to be removed, and resin components (binder, separator, etc.) to be carbonized. Furthermore, when a charged lithium ion secondary battery 1 is to be collected, the function as a battery can be stopped by carrying out the heating step S12. This allows subsequent steps to be carried out safely. As for the method of the heating step S12, any technique used in conventional collection techniques can be used without particular limitation, and since it does not characterize the technique disclosed herein, a detailed description will be omitted.

[0026] The heating step S12 is not essential and can be omitted as necessary. For example, there are cases where a recovery target that does not require removal of liquid components and does not require stopping the function of a battery, such as process waste of a positive electrode plate 30, is prepared in the preparation step S10. In this case, valuable metals can be efficiently recovered even if the heating step S12 is omitted.

[0027] (1-3) Sorting process S18 In the sorting step S18, each member contained in the object to be collected is sorted. The method of the sorting step S18 can be a conventionally known method, and for example, sorting can be performed using a sieve or visually. For example, when the object to be collected is a process waste of a positive electrode plate 30, the positive electrode core 32 is selected from the process waste and removed from the object to be collected. When the object to be collected is an electrode body 20, in addition to the positive electrode core 32, the negative electrode plate 40 is also removed from the object to be collected. Furthermore, when the object to be collected is a lithium-ion secondary battery 1, in addition to the positive electrode core 32 and the negative electrode plate 40, the case 10 is also removed from the object to be collected. This reduces the content of other metals (Al, Cu, etc.) in the object to be collected, which contributes to improving the recovery efficiency of valuable metals (Co, Ni).

[0028] In addition, in the sorting step S18, the objects to be collected may be subjected to a crushing process as necessary. This can improve the efficiency of sorting each component. For example, when the objects to be collected are lithium-ion secondary batteries 1, it is preferable to crush the case 10 and the electrode body 20. This makes it easier to remove the case 10, the positive electrode core 32, and the negative electrode plate 40 from the objects to be collected.

[0029] Moreover, the sorting step S18 is not a step intended to completely remove other metal components such as Al and Cu from the object to be recovered. Although details will be described later, even if Al remains in the object to be recovered, valuable metals (Ni and / or Co) and Al can be sufficiently separated in a subsequent step (e.g., ammine complex formation step S30). That is, the sorting step S18 can be omitted as necessary. For example, in the case of an object to be recovered that has a low content of other metal components (such as process waste of positive electrode plate 30), valuable metals can be efficiently recovered even if the sorting step S18 is omitted.

[0030] (2) Acid leaching process S20 In the acid leaching step S20, the object to be recovered is immersed in an acid solution. As a result, valuable metals (Ni and / or Co) in the object to be recovered are dissolved in the acid solution. In addition to valuable metals, other metal materials (such as Al) may also be dissolved in the acid solution in the acid leaching step S20. That is, the acid solution that has been subjected to the acid leaching step S20 (hereinafter, also referred to as the "acid leaching solution") may contain, for example, Li, Al, Cu, Co, Ni, Mn, and the like. The procedure for acid leaching can be a conventionally known procedure without any particular restrictions. As an example, the pH of the acid solution used in the acid leaching step S20 is preferably -1.5 to 1.5 (more preferably -0.5 to 0.5). This allows the metal components in the object to be suitably dissolved. Specific examples of the acid solution include inorganic acids such as sulfuric acid, nitric acid, hydrochloric acid, and phosphoric acid, and organic acids such as citric acid, ascorbic acid, oxalic acid, and acetic acid. In addition, in the acid leaching step S20, a reducing agent such as hydrogen peroxide can be added in addition to the acid solution. This improves the dissolution rate of the material to be recovered in the acid solution, and the acid leaching step S20 can be shortened. In addition, in the acid leaching step S20, it is preferable to perform a filtration process on the acid leaching solution after acid leaching. This allows undissolved components (such as carbon components) to be efficiently removed. The temperature of the acid solution is preferably 50°C or higher (more preferably 55°C or higher, and particularly preferably 60°C or higher). This allows the acid leaching step S20 to be shortened. 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. The concentration of Ni and Co (the sum of Ni and Co) in the acid leaching solution after the acid leaching step S20 is not particularly limited, but the higher the concentration, the more preferable it is from the viewpoint of productivity. Therefore, the concentration of Ni and Co (the sum of Ni and Co) in the acid leaching solution is preferably 1.0 mol / L to 2.0 mol / L. The concentrations of Ni and Co (the sum of Ni and Co) in the acid leachate can be determined by ICP analysis.

[0031] (3) Ammine complex formation step S30 In the ammine complex formation step S30, the acid leaching solution obtained in the acid leaching step S20 is mixed with an ammonia solution. This produces an ammonia solution (hereinafter referred to as a "metal solution") containing an ammine complex of a valuable metal (Ni and / or Co). More specifically, the hydroxides of Ni and Co in the acid leaching solution typically produce an ammine complex in the ammonia solution. In this specification, the "ammonia solution" refers to an aqueous solution containing ammonium ions in water as a solvent.

[0032] In the prior art, an alkaline solution (e.g., sodium hydroxide, etc.) is dropped onto valuable metals (Ni and / or Co) in the acid leachate to neutralize the acid leachate, and Al in the acid leachate is precipitated as Al hydroxide (Al(OH)3). At this time, as the pH of the acid leachate increases, more Al in the acid leachate is precipitated as hydroxide. However, if the pH becomes too high (typically pH 6.0 or higher), some of the Ni and Co in the acid leachate also produce hydroxides and begin to precipitate as a precipitate.

[0033] Here, in this embodiment, the acid leaching solution is mixed with an ammonia solution. Valuable metals (Ni and / or Co) in the acid leaching solution generate hydroxides in the ammonia solution. By further mixing the ammonia solution, the hydroxides of the valuable metals are converted into ammine complexes of the valuable metals ([Ni(NH3)6] 2+ , [Co(NH3)6] 2+ ) is produced. The ammine complex of the valuable metal is dissolved in the ammonia solution. Meanwhile, when the Al in the acid leaching solution is mixed with the ammonia solution, it produces a hydroxide and precipitates. Even when the ammine complex of the valuable metal is produced, Al remains as a precipitate in the form of hydroxide without producing an ammine complex. This allows Al to be selectively precipitated as a precipitate while the valuable metal (Ni and / or Co) in the acid leaching solution remains in the solution.

[0034] The ammonia solution used in the ammine complex formation step S30 may be, for example, a commercially available product (ammonia water), or may be a solution in which at least a solvent containing water and an ammonia salt are dissolved. As the ammonia salt used in the ammonia solution, for example, ammonium hydroxide (NH4OH), ammonium sulfate ((NH4)2SO4), ammonium carbonate ((NH4)2CO3), ammonium hydrogen carbonate (NH4HCO3), ammonium chloride (NH4Cl), ammonium fluoride (NH4F), etc. may be appropriately used. These compounds may be used alone or in combination of two or more.

[0035] In some preferred embodiments, the ammonia solution preferably contains at least one selected from the group consisting of ammonium sulfate, ammonium chloride, and ammonium acetate. These act as so-called pH buffers for the ammonia solution. In more detail, the pH of the ammonia solution can be lowered. By lowering the pH of the ammonia solution, Ni and / or Co can preferably form an ammine complex while suppressing the dissolution of Al in the ammonia solution. Furthermore, according to the above-mentioned configuration, the ammonia concentration of the ammonia solution can be increased, so that Ni and / or Co can preferably form an ammine complex. Therefore, a metal solution containing Ni and / or Co can be selectively obtained from the acid solution containing the recovery target. That is, the recovery rate of valuable metals (Ni and / or Co) can be preferably improved. It is not necessary to use the ammonia solution containing at least one selected from the group consisting of ammonium sulfate, ammonium chloride, and ammonium acetate alone, and a separate ammonia solution may be further prepared. In that case, the timing of mixing in the ammine complex formation step S30 may be simultaneous or separate.

[0036] The pH adjusted in the ammine complex formation step S30 is preferably pH 9.5 or higher, more preferably pH 10.1 or higher. If the pH of the acid leaching solution is too low (typically less than pH 9), the valuable metals (Ni and / or Co) in the acid leaching solution do not easily form ammine complexes. In other words, the valuable metals do not easily dissolve in the metal solution. If the pH of the metal solution is within a suitable numerical range, the valuable metals in the metal solution preferably form ammine complexes. In other words, Al can be more preferably separated from the acid leaching solution. On the other hand, if the pH is too high (typically more than pH 11.5) with respect to the upper limit of the pH adjusted in the ammine complex formation step S30, a part of Al (aluminum hydroxide) will become hydroxide complexes ([Al(OH)4] ― ) and begins to dissolve in the metal solution. Therefore, the pH adjusted in the ammine complex formation step S30 is preferably pH 11.5 or less, and more preferably pH 11.0 or less.

[0037] The ammonia concentration of the ammonia solution in the ammine complex formation step S30 is not particularly limited since it may vary depending on the concentration of valuable metals (Ni and / or Co) in the acid leachate, but is preferably 10 wt% or more, and more preferably 20 wt% or more. As the ammonia concentration increases, Ni and / or Co favorably form ammine complexes, making it possible to more efficiently recover valuable metals (Ni and / or Co) from the precipitate. On the other hand, in view of the high volatility of ammonia, the upper limit of the ammonia concentration in the ammonia solution is, but is not limited to, for example, 35 wt% or less, and preferably 30 wt% or less.

[0038] The temperature of the mixture in the ammine complex formation step S30 is not particularly limited, but is preferably 25° C. or higher, more preferably 40° C. or higher, and particularly preferably 60° C. or higher. This allows the time for the ammine complex formation step S30 to be shortened. On the other hand, the upper limit of the temperature of the mixture is not particularly limited, but is preferably 100° C. or lower, more preferably 90° C. or lower, and particularly preferably 80° C. or lower.

[0039] The time for the ammine complex formation step S30 is not particularly limited because it may vary depending on, for example, the ammonia concentration in the reaction solution and the reaction temperature, but is preferably about 0.5 hours or more, more preferably 1 hour or more, and particularly preferably 2 hours or more. On the other hand, from the viewpoint of productivity, the time for the ammine complex formation step S30 is preferably about 8 hours or less, more preferably 6 hours or less, and particularly preferably 4 hours or less. Although not particularly limited, it is preferable to perform the ammine complex formation step S30 while stirring the ammonia solution. This increases the contact area between the valuable metal (Ni and / or Co) and the ammonia solution, making it possible to efficiently form an ammine complex of the valuable metal. Therefore, the time for the ammine complex formation step S30 can be shortened.

[0040] (4) Solid-liquid separation process S40 In the solid-liquid separation step S40, the precipitate (residue) in the metal solution after the ammine complex formation step S30 is removed by solid-liquid separation. This makes it possible to obtain a metal solution containing at least one of Ni and Co. The method of solid-liquid separation can be a conventionally known method. The metal solution obtained by the solid-liquid separation step S40 is typically a solution in which valuable metals (Ni and / or Co) are dissolved in an ammonia solution in the form of an ammine complex. Since Al has been removed from the metal solution obtained by the solid-liquid separation step S40, a step of further removing Al is not required. That is, there is no loss of valuable metals due to washing, Al extraction, or the like. The use of the metal solution is not particularly limited to this, but it can be suitably used, for example, as an alkaline solution in the precursor preparation step S50 described later.

[0041] As described above, in the manufacturing method disclosed herein, an ammine complex formation step is performed in which an ammonia solution is mixed with an acid leachate containing a recovery target, thereby enabling recovery of a metal solution in which valuable metals (Ni and / or Co) are dissolved as ammine complexes. Conventionally, valuable metals (Ni and / or Co) and Al are separated from each other by performing a neutralization step in which an acid leachate that has been subjected to an acid leaching step is neutralized with an alkaline solution (such as NaOH). In this case, a part of the valuable metals (Ni and / or Co) may also precipitate together with Al as a precipitate, resulting in a loss of valuable metals, or there is a problem that Al cannot be sufficiently separated from the acid leachate in order to reduce such loss, since the pH cannot be sufficiently increased in the neutralization step in an attempt to suppress the precipitation of valuable metals. On the other hand, in the manufacturing method disclosed herein, Al can be suitably removed as a precipitate from the acid leachate by the ammine complex formation step. Then, the valuable metals (Ni and / or Co) form ammine complexes and are dissolved in the metal solution. Therefore, the recovery rate of the valuable metals from the object of recovery can be improved.

[0042] The method for producing a battery material disclosed herein may further include a precursor preparation step S50 and an active material production step S60. These steps will be described in detail below.

[0043] (5) Precursor preparation process S50 In the precursor preparation step S50, a positive electrode active material precursor (metal composite hydroxide) is prepared. In the precursor preparation step S50, a conventionally known method (such as a crystallization method) can be used without any particular restrictions. For example, an aqueous solution containing a metal element source (typically a water-soluble ionic compound) is prepared. Next, the aqueous solution containing the prepared metal element source and an alkaline solution (such as an ammonia solution) are mixed in a reaction tank, and the mixture is stirred while controlling the pH, thereby coprecipitating and crystallizing particles of the metal composite hydroxide in the reaction tank. For example, various metal components obtained in the solvent extraction step can be used as the metal element source.

[0044] In some preferred embodiments, it is preferable to prepare a positive electrode active material precursor (metal composite hydroxide) using a metal solution obtained by carrying out the above-mentioned ammine complex formation step S30 as the alkaline solution in the precursor preparation step S50. The above metal solution contains Ni and / or Co in an ammonia solution. Therefore, the above metal solution does not need to be treated by washing or the like and can be used as it is as the alkaline solution in the precursor preparation step S50. Therefore, Co and Ni in the ammonia solution can also be crystallized as a positive electrode active material precursor. That is, the valuable metals (Ni and / or Co) recovered from the acid leachate in the ammine complex formation step S30 can be used efficiently.

[0045] As described above, in the precursor preparation step S50, crystallization is performed while controlling the pH of the mixed solution. At this time, an alkaline solution (such as an aqueous NH3 solution or an aqueous NaOH solution) for adjusting the pH can be dropped into the reaction tank. The amount of Ni and Co in the metal solution obtained in the ammine complex formation step S30 can be determined by ICP analysis. For this reason, Ni, Co, or other metal components such as Mn may be added depending on the composition of the target positive electrode active material. Such metal components may be added in the form of metal sulfates, hydrates, etc.

[0046] (6) Active material generation step S60 In the active material generating step S60, a battery material (positive electrode active material) is generated using the metal compound obtained in the precursor producing step S50 and a Li compound (e.g., Li2CO3, etc.). For example, the positive electrode active material precursor (metal composite hydroxide) obtained in the precursor producing step S50 is mixed with a Li compound, and the mixture is fired. This allows the positive electrode active material (lithium transition metal composite oxide) of a lithium ion secondary battery to be manufactured.

[0047] In the manufacturing method according to the above embodiment, in addition to the preparation step S10, the acid leaching step S20, the ammine complex formation step S30, and the solid-liquid separation step S40, a precursor preparation step S50 and an active material formation step S60 are performed. However, the description of the above embodiment is not intended to limit the steps other than the preparation step S10, the acid leaching step S20, the ammine complex formation step S30, and the solid-liquid separation step S40. In other words, in the manufacturing method disclosed herein, the steps other than the preparation step S10, the acid leaching step S20, the ammine complex formation step S30, and the solid-liquid separation step S40 can be appropriately added, deleted, or changed as necessary.

[0048] 3. Other embodiments An embodiment of the technology disclosed herein has been described above. Note that the technology disclosed herein is not limited to the above embodiment, and includes other embodiments in which various configurations are modified. Other examples of the embodiment of the technology disclosed herein will be described below.

[0049] In the manufacturing method according to the above embodiment, a technique for recovering valuable metals (Ni and / or Co) from a target to be recovered has been described. However, in some embodiments, the target to be recovered may further contain Li. In this case, Li can be recovered (produced) in addition to the valuable metals in the target to be recovered.

[0050] <Second embodiment> When the object to be recovered contains Li, the following embodiment can be given as an example of a means for recovering Li. FIG. 5 is a flow chart for explaining a method for producing a battery material according to a second embodiment. FIG. 6 is a flow chart for explaining in detail a solvent extraction step S70 according to a second embodiment. As shown in FIG. 5, the second embodiment includes a solvent extraction step S70 and a Li crystallization step S80 after a solid-liquid separation step S40. Note that other than this point, it may be the same as the above embodiment, and since it has already been explained, a duplicated description will be omitted. A specific description will be given below.

[0051] (7) Solvent extraction process S70 In the solvent extraction step S70, valuable metals (Ni and / or Co) are extracted from the metal solution using a solvent extraction method. In addition, in the solvent extraction step S70, other metal components (Li, etc.) in the metal solution can also be separated. Specifically, the solvent extraction step S70 in this embodiment includes a Co extraction step S71 and a Ni extraction step S72, as shown in FIG. 6. This makes it possible to prepare both a Co solution and a Ni solution. However, in the solvent extraction step S70, steps can be added, changed, or deleted as appropriate depending on the metal components contained in the metal solution. A specific explanation will be given below.

[0052] (7-1) Co extraction process S71 In the Co extraction step S71, an organic solvent (first extraction liquid) that has high extractability for Co and low extractability for Li, Cu, and Ni is added to the metal solution. This separates Co from the metal solution, and a Co solution in which Co is dissolved in the first extraction liquid can be obtained. Specific examples of the second extraction liquid include phosphonic acid esters such as 2-ethylhexyl phosphonic acid 2-ethylhexyl (PC-88A). The first extraction liquid may be a mixture or dilution of these extractants. Then, in the Co extraction step S71, the metal solution and the first extraction liquid are stirred and suspended. This dissolves Co in the metal solution in the first extraction liquid. Then, by leaving the two liquids to separate, a Co solution in which Co is dissolved in the first extraction liquid and a metal solution from which Co has been removed can be obtained.

[0053] In the Co extraction step S71, a back extraction process may be performed on the extracted Co solution (first extract solution containing Co). In this back extraction process, first, the Co solution (organic phase) and an acidic aqueous solution are stirred and mixed in a mixer or the like. Then, the mixture is left to stand until the two liquids are separated. In this way, an aqueous Co solution can be obtained. Examples of the acidic aqueous solution used in the back extraction process include sulfuric acid, hydrochloric acid, etc. (particularly sulfuric acid).

[0054] (7-2)Ni extraction process S72 In the Ni extraction step S72, an organic solvent (second extraction liquid) that has high extractability for Ni and low extractability for Li and Cu is added to the metal solution. This separates Ni from the metal solution, and a Ni solution in which Ni is dissolved in the second extraction liquid can be obtained. Specific examples of the third extraction liquid include carboxylic acid extractants such as neodecanoic acid and naphthenic acid. In addition, a back extraction process may also be performed on the Ni solution after extraction (second extraction liquid containing Ni). This allows an aqueous Ni solution to be obtained. The procedure for the back extraction process has already been described, so a duplicated description will be omitted.

[0055] The specific processing procedure in the solvent extraction step S70 can be changed as appropriate. For example, the solvent extraction step S70 in the above embodiment includes a Co extraction step and a Ni extraction step. This allows a Co solution and a Ni solution to be extracted separately. However, in the solvent extraction step S70, Ni and Co may be extracted simultaneously. This allows the process to be shortened to improve the manufacturing efficiency. The valuable metals (Ni and / or Co) obtained in the solvent extraction step S70 can be used, for example, as a metal element source in the precursor preparation step S50, but is not limited thereto.

[0056] (8) Li crystallization process S80 In the Li crystallization step S80, crystals of a Li compound are precipitated from the metal solution after the solvent extraction step S70. In the Li crystallization step S80, a conventionally known crystallization process can be adopted without any particular limitation. For example, in the Li crystallization step S80, sodium carbonate may be added to the metal solution. This allows crystals of lithium carbonate (Li2CO3) to be precipitated. The Li compound generated in the Li crystallization step S80 is not limited to lithium carbonate. For example, lithium hydroxide (LiOH) may be generated as the Li compound as necessary. In the generation of this lithium hydroxide, first, the lithium carbonate precipitated from the metal solution is dissolved (or suspended) in a predetermined solvent. Then, calcium hydroxide is added to this solution. After that, the solvent is evaporated and removed as necessary. This allows crystals of lithium hydroxide to be precipitated. The crystals of the Li compound precipitated in the Li crystallization step S80 can be used, for example, in the active material generation step S60, although this is not limited thereto.

[0057] In some embodiments, the metal solution after the solvent extraction step S70 may be subjected to a Li separation step. The Li separation step is a step of further removing other metal components (Cu, etc.) from the metal solution to prepare a high-concentration Li solution. This allows a high-purity Li compound to be obtained in the Li crystallization step S80. The means for preparing the Li solution is not particularly limited, and it is preferable to appropriately adopt a conventionally known means such as a solvent extraction method or an ion exchange method. Instead of the Li concentration step, only evaporation of the solvent may be performed. Even in this case, a high-concentration Li solution can be obtained.

[0058] In some embodiments, a Li concentration step may be performed on the metal solution after the Li separation step. In this Li concentration step, the Li solution is heated to evaporate the solvent. This makes it possible to obtain a high-concentration Li solution, thereby improving the crystallization efficiency in the Li crystallization step S80. This Li concentration step may be performed on a metal solution that has not been subjected to the Li separation step. Even in this case, a high-concentration Li solution can be obtained.

[0059] <Third embodiment> The manufacturing method of the battery material according to the second embodiment has been described above. However, the means for recovering Li is not limited to this. Another example of the Li recovery method when the recovery target contains Li can be further exemplified by the following embodiment. FIG. 7 is a flow chart for explaining the manufacturing method of the battery material according to the third embodiment. FIG. 8 is a flow chart for explaining in detail the preparation step S110 according to the third embodiment. As shown in FIG. 7 and FIG. 8, the third embodiment includes a preparation step S110 including a recovery target preparation step S11, a chlorination heating step S14, a water dissolving step S16, and a sorting step S18, instead of the preparation step S10. Note that other than this point, it may be the same as the above embodiment, and since it has already been described, a duplicate description will be omitted. In addition, the recovery target preparation step S11 and the sorting step S18 may be the same as the above embodiment, and the description will be omitted here. A specific description will be given below.

[0060] (1-4) Chloridation heating step S14 In the chlorination heating step S14, the object to be recovered is heated together with a non-metallic chlorine compound (such as HCl). As a result, Li in the object to be recovered reacts with the non-metallic chlorine compound to generate lithium chloride (LiCl). This LiCl is easily dissolved in water such as pure water or ion-exchanged water. Therefore, it can be easily separated from the object to be recovered by the water dissolution step S16 described later.

[0061] (1-5) Water dissolution step S16 In the water dissolving step S16, the object to be recovered after the chlorination heating step S14 is immersed in water. This makes it possible to obtain a Li solution in which LiCl is dissolved in water. The Li solution obtained in the water dissolving step S16 can be used to precipitate crystals of a Li compound by a method similar to that of the Li crystallization step S80 described above, but is not limited thereto. The crystals of the Li compound thus obtained can be used, for example, as the Li compound in the active material production step S60 (see FIG. 7).

[0062] The recovery target (typically, metal components other than Li) that was not salified in the chlorination heating step S14 remains as a solid content after the water dissolution step S16. In this embodiment, the solid content (recovery target) after the water dissolution step S16 can be subjected to the sorting step S18, the acid leaching step S20, the ammine complex formation step S30, and the solid-liquid separation step S40 according to the above-mentioned embodiment. In this embodiment, Li in the recovery target is recovered in advance before the acid leaching step S20 by the chlorination heating step S14 and the water dissolution step S16. That is, the metal solution obtained in the solid-liquid separation step S40 does not contain Li. Therefore, the metal solution can be used directly in the precursor preparation step S50 without going through the solvent extraction step. As a result, in this embodiment, valuable metals (Ni and / or Co) contained in the metal solution can be efficiently utilized while recovering (producing) Li from the recovery target.

[0063] [Test example] Test examples relating to the technology disclosed herein will be described below. Note that the contents of the test examples described below are not intended to limit the technology disclosed herein.

[0064] <Test Example 1: Study of pH during neutralization precipitation process> (Example 1) In this test, the positive electrode plate was used as the object to be collected, and the following process was carried out on the object to be collected. Specifically, the positive electrode plate used had a positive electrode core (Al foil) with a positive electrode active material layer applied to its surface. The positive electrode active material used in this test was lithium nickel cobalt manganese composite oxide (LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2) was used. The positive electrode plate was crushed and sieved through a 500 μm mesh sieve to obtain a powder for use as a test sample. When the powder for the test sample was analyzed by ICP, the mass ratio of Al to the total amount of Ni and Co in the sample was found to be 4 wt%.

[0065] Next, the test sample was mixed with a mixture (pH 0) of sulfuric acid (H2SO4) (concentration 2 mol / L) as an acid solution and hydrogen peroxide (H2O2) (concentration 0.6 mol / L) as a reducing agent. The acid solution was stirred at a stirring speed of 600 rpm for 6 hours while maintaining the temperature at 80°C. After stirring, the acid leachate was filtered and the resulting acid leachate was analyzed by ICP to measure the amounts of Al, Ni, and Co. The ICP measurement results showed that the concentrations of Ni and Co (the sum of Ni and Co) in the acid leachate were 1.0 mol / L.

[0066] The acid leachate obtained above was maintained at 25°C, and an ammonia (NH3) solution with an ammonia concentration of 28 wt% was added dropwise to the acid leachate while stirring at a stirring speed of 600 rpm (corresponding to the "Alkaline solution" column in Table 1). When the pH of the acid leachate reached 4.2, the addition of the ammonia solution was stopped. After the dropwise addition was stopped, stirring was continued at a stirring speed of 600 rpm for 10 minutes, and it was confirmed that the pH did not change. Then, the metal solution and the precipitate were separated into solid and liquid by filtration.

[0067] (Examples 2 to 5) In Examples 2 to 5, the dropwise addition of the ammonia solution was stopped at the pH shown in Table 1. Other than this, the procedures were the same as in Example 1.

[0068] (Example 6, Example 7) In Examples 6 and 7, the acid leaching solution obtained above was maintained at 80° C., and the dropwise addition of the ammonia solution was stopped when the pH value was as shown in Table 1. The rest of the procedures were the same as in Example 1.

[0069] (Example 8) In Example 8, 2 mol / L of ammonium sulfate ((NH4)2SO4) was added as a pH buffer before the ammonium solution was added. The same ammonia solution as in Example 1 was then added, and the addition of the ammonia solution was stopped when the pH of the acid leachate reached 10.1. The rest of the procedure was the same as in Example 1.

[0070] (Example 9 to Example 15) In Examples 9 to 15, instead of the ammonia solution, a sodium hydroxide (NaOH) solution with a concentration of 10 wt% was used and dropped onto the acid leaching solution (corresponding to the "Alkaline solution" column in Table 1). Then, the dropping of the sodium hydroxide solution was stopped when the pH value was as shown in Table 1. The rest of the procedure was the same as in Example 1.

[0071] In all of Examples 1 to 15, a precipitate was observed at the end of the dropwise addition of the alkaline solution (ammonia solution or sodium hydroxide solution).

[0072] [Metal Residual Rate in Solution] The residual rate of valuable metals (Ni, Co) and Al in the metal solution of each example was calculated. Specifically, first, the metal solution was subjected to ICP to measure the amount of each substance of Ni, Co, and Al in the metal solution. Then, based on the following formulas (1) and (2), the residual rate of Ni, Co in the metal solution and the residual rate of Al in the metal solution were calculated, respectively, compared with the acid leachate of each example (i.e., before titration). It can be said that the higher the residual rate of Ni, Co in the metal solution, the more Ni and Co that had leached into the acid leachate before the alkaline solution (ammonia solution or sodium hydroxide solution) was dissolved in the metal solution. Therefore, it is considered that the higher the residual rate of Ni, Co in the metal solution, the better the result in this test example. On the other hand, it can be said that the lower the residual rate of Al in the metal solution, the more appropriately Al in the acid leachate is separated (typically precipitated as a precipitate). Therefore, it can be said that the lower the residual rate of Al in the metal solution, the better the result in this test example. The results are shown in Table 1. Ni, Co remaining rate in metal solution (%) = {(amount of Ni in metal solution + amount of Co in metal solution) / (amount of Ni in acid leachate + amount of Co in acid leachate) × 100 ... (1) Al remaining rate in metal solution (%) = (Amount of Al in metal solution / Amount of Al in acid leachate) × 100…(2)

[0073] [Table 1]

[0074] As shown in the results in Table 1, in Examples 9 to 15, in which a sodium hydroxide (NaOH) solution was used as the alkaline solution, the residual Al rate and the residual Ni and Co rates in the metal solution decreased as the pH increased. This is believed to be because Al in the acid leaching solution was precipitated as aluminum hydroxide, while Ni and Co in the acid leaching solution also formed hydroxides and were similarly precipitated as precipitates. On the other hand, in Examples 1 to 5, in which an ammonia (NH3) solution was used as the alkaline solution, the Al residual rate in the metal solution decreased as the pH increased, as in Examples 9 to 15. As for Ni and Co, the Ni and Co residual rates in the metal solution decreased in Examples 3 and 4, in which the pH of the metal solution was 6.0 and 9.0, respectively. This is believed to be because Ni and Co in the acid leachate formed hydroxides and precipitated as the pH increased. However, in Example 5, in which the metal solution had a pH of 11.0, the Ni and Co residual rates in the metal solution increased again. This is believed to be because the hydroxides of Ni and Co in the acid leachate further formed ammine complexes with ammonia ions in the ammonia solution. This is believed to have caused Ni and Co to dissolve in the metal solution as ammine complexes. In addition, since the hydroxide of Al does not form an ammine complex, it is believed to be suitably separated as hydroxide in Example 5 as well. In other words, by mixing an ammonia solution with the acid leachate from which the recovery target containing valuable metals (Ni and / or Co) has been leached, and generating an ammine complex of the valuable metal (Ni and / or Co), Al can be suitably separated and a metal solution containing the valuable metal can be suitably obtained.

[0075] In Example 6, where the solution temperature was maintained at 80°C, an ammine complex of Ni and Co was favorably formed, and good results were obtained with respect to the separation of Al. In Example 7, where the pH of the metal solution was 12.1, good results were obtained with respect to the Ni and Co remaining rate in the metal solution, but the Ni and Co remaining rate in the metal solution was 0.9%, which was slightly higher than that in Example 6, where the pH of the metal solution was 11.0. This is because a part of the Al hydroxide as a precipitate was converted into a hydroxide complex ([Al(OH)4]) that was soluble in the metal solution. ―In Example 8, where ammonium sulfate was added to the acid leaching solution in addition to the ammonia solution, very good results were obtained for both the Ni, Co and Al remaining rates in the metal solution. This is thought to be because the addition of ammonium sulfate made it possible to increase the ammonia concentration while keeping the pH of the metal solution at 10.1, which allowed for the formation of Ni, Co ammine complexes while favorably precipitating Al.

[0076] Although the technology disclosed herein has been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes to the specific examples exemplified above. In other words, the technology disclosed herein includes the embodiments described in items 1 to 7 below.

[0077] <Item 1> A preparation step of preparing a recovery target containing at least one of Ni and Co; an acid leaching step of immersing the recovery target in an acid solution to obtain an acid leaching solution; an ammine complex formation step of mixing an ammonia solution containing ammonium ions with the acid leaching solution to form a metal solution containing an ammine complex of at least one of the Ni and Co; A solid-liquid separation step of obtaining the metal solution by solid-liquid separation. Manufacturing method for battery materials.

[0078] <Item 2> 2. The method for producing a battery material according to item 1, wherein the ammonia solution contains at least one selected from the group consisting of ammonium sulfate, ammonium chloride, and ammonium acetate.

[0079] <Item 3> 3. The method for producing a battery material according to item 1 or 2, wherein the pH of the ammonia solution is adjusted to 9.5 to 11.5 and the ammine complex formation step is carried out.

[0080] <Item 4> 4. The method for producing a battery material according to any one of items 1 to 3, wherein the ammine complex formation step is carried out at a temperature of the ammonia solution of 25 to 100° C.

[0081] <Item 5> 5. The method for producing a battery material according to any one of items 1 to 4, further comprising a precursor preparation step of preparing a positive electrode active material precursor using the metal solution.

[0082] <Item 6> 6. The method for producing a battery material according to any one of items 1 to 5, wherein the object to be recovered contains Li.

[0083] <Item 7> 7. The method for producing a battery material according to any one of items 1 to 6, further comprising a solvent extraction step of extracting at least one of the Ni and the Co from the metal solution.

[0084] <Item 8> The above preparation process is a chlorination heating step of heating the recovery target together with a non-metallic chlorine compound to produce LiCl; 8. The method for producing a battery material according to item 6 or 7, further comprising a water dissolving step of immersing the recovery target after the chlorination heating step in water to obtain a Li solution in which the LiCl is dissolved in the water. [Explanation of symbols]

[0085] 1. Lithium-ion secondary battery 10 Cases 12 Positive terminal 14 Negative terminal 20 Electrode body 30 Positive plate 32 Positive electrode core 34 Cathode active material layer 40 Negative plate 42 Negative electrode core 44 Negative electrode active material layer 50 Separator

Claims

1. A preparation step of preparing a recovery target containing at least one of Ni and Co; an acid leaching step of immersing the recovery target in an acid solution to obtain an acid leaching solution; an ammine complex generating step of mixing an ammonia solution containing ammonium ions with the acid leaching solution to generate a metal solution containing an ammine complex of at least one of the Ni and the Co; A solid-liquid separation step of obtaining the metal solution by solid-liquid separation; Manufacturing method for battery materials.

2. The method for producing a battery material according to claim 1 , wherein the ammonia solution contains at least one selected from the group consisting of ammonium sulfate, ammonium chloride, and ammonium acetate.

3. 3. The method for producing a battery material according to claim 1, wherein the pH of the ammonia solution is adjusted to 9.5 to 11.5, and the ammine complex formation step is carried out.

4. 3. The method for producing a battery material according to claim 1, wherein the ammine complex formation step is carried out at a temperature of the ammonia solution of 25 to 100° C.

5. The method for producing a battery material according to claim 1 or 2, further comprising a precursor preparation step of preparing a positive electrode active material precursor using the metal solution.

6. The method for producing a battery material according to claim 1 , wherein the target to be recovered includes Li.

7. The method for producing a battery material according to claim 6 , further comprising a solvent extraction step of extracting at least one of the Ni and the Co from the metal solution.

8. The preparation step includes: a chlorination heating step of heating the recovery target together with a non-metallic chlorine compound to generate LiCl; The method for producing a battery material according to claim 6 , further comprising a water dissolving step of immersing the recovery target after the chlorination heating step in water to obtain a Li solution in which the LiCl is dissolved in the water.

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