Method for producing mixed metal solution and method for producing mixed metal salt

Abstract

A method for producing a metal mixed solution containing at least one of cobalt ions and nickel ions and manganese ions, comprising: an Al removal step, in which, for an acidic solution containing at least one of cobalt ions and nickel ions, manganese ions and aluminum ions obtained by supplying battery powder of lithium ion battery waste to a leaching step, at least a part of the manganese ions in the acidic solution is left in an aqueous phase, and aluminum ions are extracted into a solvent for removal; and a metal extraction step, in which, for an extract residue obtained by the Al removal step, a solvent containing a carboxylic acid extractant is used to adjust the equilibrium pH to 6.5 to 7.5, and at least one of cobalt ions and nickel ions and manganese ions in the extract residue are extracted into the solvent, and then the cobalt ions and at least one of nickel ions and manganese ions are stripped from the solvent.

Description

Technical Field

[0001] This specification discloses technologies related to a method for producing a metal mixed solution and a method for producing a mixed metal salt. Background Art

[0002] In recent years, from the viewpoint of effective utilization of resources, there has been extensive research into recovering valuable metals such as cobalt and nickel contained in lithium ion battery waste including positive electrode materials of lithium ion secondary batteries discarded due to product life or manufacturing failure, etc., by wet treatment.

[0003] In the process of recovering valuable metals from lithium-ion battery waste, for example, battery powder obtained through a predetermined process such as roasting is usually added to an acid for leaching to obtain a leached liquid in which cobalt, nickel, manganese, iron, aluminum, etc. that may be contained therein are dissolved.

[0004] Then, iron and the like are separated and removed from the leached liquid, and each metal ion in the separated liquid is further extracted by a multi-stage solvent extraction. In the multi-stage solvent extraction, specifically, manganese ions and aluminum ions are first extracted into a solvent and removed. Next, after the cobalt ions are extracted and stripped, the nickel ions are extracted and stripped. The solution containing the cobalt ions and the solution containing the nickel ions obtained by each stripping are electrolyzed, and the cobalt and nickel are respectively recovered in the state of metal (see, for example, Patent Document 1).

[0005] Prior Art Literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2014-162982 Summary of the invention

[0008] Problems to be solved by the invention

[0009] However, in the above-mentioned metal recovery process, if cobalt, nickel and manganese can be recovered in the state of a higher purity metal mixed solution in which two or three metals are dissolved, or a higher purity mixed metal salt containing each metal salt of two or three metals, it is possible to use it directly as a raw material for manufacturing anode materials of lithium-ion batteries. For example, in the case of obtaining a higher purity metal mixed solution in which cobalt, nickel and manganese are dissolved, or a higher purity mixed metal salt containing each metal salt of these three metals, it is possible to use it directly as a raw material for manufacturing anode materials of ternary systems of lithium-ion batteries. In this case, the aforementioned electrolysis and other treatments can be omitted, so that the simplification of the process and the substantial reduction of costs can be expected.

[0010] Here, in the above-mentioned metal recovery process, in the initial solvent extraction, not only aluminum ions but also manganese ions are extracted, so due to the lack or insufficiency of manganese, a metal mixed solution or mixed metal salt containing two or three metals of manganese in an appropriate ratio cannot be obtained. However, if aluminum is not fully extracted and removed, there is a concern that it is contained as an impurity in the metal mixed solution or mixed metal salt, thereby reducing the purity.

[0011] This specification discloses a method for producing a metal mixed solution and a method for producing a mixed metal salt, which are capable of efficiently producing a relatively pure metal mixed solution or a mixed metal salt containing at least one of manganese ions, cobalt ions, and nickel ions.

[0012] Means for solving problems

[0013] The method for producing a metal mixed solution disclosed in the present specification is a method for producing a metal mixed solution containing at least one of cobalt ions and nickel ions and manganese ions, wherein the method for producing a metal mixed solution comprises: an Al removal step, in which, for an acidic solution containing at least one of cobalt ions and nickel ions, manganese ions, and aluminum ions obtained by supplying battery powder of lithium ion battery waste to a leaching step, at least a part of the manganese ions in the acidic solution is left in an aqueous phase, and aluminum ions are extracted into a solvent for removal; and a metal extraction step, in which, for the residual extract obtained by the Al removal step, a solvent containing a carboxylic acid extractant is used to adjust the equilibrium pH to 6.5 to 7.5, and at least one of cobalt ions and nickel ions and manganese ions in the residual extract are extracted into the solvent, and then the cobalt ions and nickel ions and manganese ions are stripped from the solvent.

[0014] The method for producing a mixed metal salt disclosed in the present specification is a method for producing a mixed metal salt comprising a metal salt of manganese and a metal salt of at least one of cobalt and nickel, wherein the method for producing a mixed metal salt comprises: a precipitation step, in which a mixed metal salt comprising a metal salt of manganese and a metal salt of at least one of cobalt and nickel is precipitated from a metal mixed solution obtained by the above-mentioned method for producing a metal mixed solution.

[0015] Effects of the Invention

[0016] According to the above-mentioned method for producing a metal mixed solution or a method for producing a mixed metal salt, a relatively high-purity metal mixed solution or a mixed metal salt containing at least one of cobalt ions and nickel ions and manganese ions can be efficiently produced. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1This is a flow chart showing an example of a process including a method for producing a mixed metal salt according to an embodiment.

[0018] Figure 2 This is a graph showing an example of an extraction curve indicating the relationship between the extraction rate of each metal and pH in extraction using a solvent containing a carboxylic acid-based extractant (VA-10). DETAILED DESCRIPTION

[0019] Hereinafter, embodiments of the method for producing the above-mentioned metal mixed solution and the method for producing the mixed metal salt will be described in detail.

[0020] A method for producing a metal mixed solution according to one embodiment is a method for producing a metal mixed solution containing at least one of manganese ions, cobalt ions and nickel ions, comprising: an Al removal step, in which an acidic solution containing at least manganese ions and aluminum ions, and at least one of cobalt ions and nickel ions, obtained by supplying battery powder of lithium ion battery waste to a leaching step, at least a portion of the manganese ions in the acidic solution is left in an aqueous phase, and the aluminum ions are extracted into a solvent for removal; and a metal extraction step, in which a solvent containing a carboxylic acid-based extractant is used to adjust the equilibrium pH to 6.5 to 7.5 for the residual extract obtained in the Al removal step, at least one of the cobalt ions and nickel ions and the manganese ions in the residual extract are extracted into the solvent, and then at least one of the cobalt ions and nickel ions and the manganese ions are stripped from the solvent.

[0021] This embodiment can be applied, for example, Figure 1 The process of recovering metals from lithium-ion battery waste is as shown in the example. Figure 1 , which is described in detail below.

[0022] (Lithium-ion battery)

[0023] The lithium ion battery waste as the object is a lithium ion secondary battery that contains at least cobalt and / or nickel and manganese as positive electrode active materials and can be used in various electronic devices such as mobile phones, and is discarded due to the life of the battery product, manufacturing failure or other reasons. From the perspective of effective utilization of resources, it is preferred to recover valuable metals from the above-mentioned lithium ion battery waste. In addition, the purpose is to be able to recover cobalt and / or nickel and manganese as valuable metals with high purity and reuse them in the manufacture of lithium ion secondary batteries.

[0024] Lithium ion battery waste has a frame containing aluminum as an outer covering that wraps around it. As the frame, for example, there is a frame consisting of only aluminum, a frame containing aluminum and iron, an aluminum laminate, etc. In addition, lithium ion battery waste sometimes contains a positive electrode active material or aluminum foil (positive electrode substrate) in the above-mentioned frame, and the positive electrode active material is composed of a single metal oxide or two or more composite metal oxides selected from the group consisting of lithium, nickel, cobalt and manganese, and the aluminum foil (positive electrode substrate) is coated with an organic binder such as polyvinylidene fluoride (PVDF) and fixed with the positive electrode active material. In addition, copper, iron, etc. are sometimes contained in lithium ion battery waste. Moreover, in lithium ion battery waste, an electrolyte is usually contained in the frame. As the electrolyte, for example, ethylene carbonate, diethyl carbonate, etc. are sometimes used.

[0025] Lithium-ion battery waste is often subjected to a pretreatment process, which may include calcination, pulverization, and sieving, thereby obtaining battery powder.

[0026] In the roasting treatment, the above-mentioned lithium ion battery waste is heated. The roasting treatment is performed, for example, for the purpose of changing metals such as lithium and cobalt contained in the lithium ion battery waste into a form that is easily soluble. In the roasting treatment, it is preferred to heat the lithium ion battery waste at a temperature range of, for example, 450°C to 1000°C, preferably 600°C to 800°C for 0.5 to 4 hours. Here, various furnaces such as a rotary kiln furnace and various heating equipment such as a furnace that heats in an atmospheric atmosphere can be used.

[0027] After the calcination process, a pulverization process can be performed to remove the positive electrode material and the negative electrode material from the frame of the lithium ion battery waste. The pulverization process is performed to destroy the frame of the lithium ion battery waste and selectively separate the positive electrode active material from the aluminum foil coated with the positive electrode active material.

[0028] In the pulverization process, various known devices or equipment can be used, but it is particularly preferred to use an impact pulverizer that can cut off the lithium ion battery waste while applying impact to pulverize. As the impact pulverizer, a sample mill, a hammer mill, a pin mill, a wing mill, a tornado mill, a hammer crusher, etc. can be cited. It should be noted that a screen can be set at the outlet of the pulverizer, whereby the lithium ion battery waste is discharged from the pulverizer through the screen when it is pulverized to a size that can pass through the screen.

[0029] After the lithium ion battery waste is crushed by the pulverization process, for example, a screening process using a sieve with an appropriate mesh is performed for the purpose of removing aluminum powder. Thus, aluminum and copper remain on the sieve, and battery powder with aluminum and copper removed to a certain extent can be obtained below the sieve.

[0030] The battery powder contains manganese, cobalt and / or nickel, for example, sometimes contains 0% to 30% by mass of cobalt, 0% to 30% by mass of nickel, and 1% to 30% by mass of manganese. In addition, the battery powder may contain aluminum, iron, copper, etc.

[0031] (Leaching process)

[0032] The battery powder is supplied to the leaching process. In the leaching process, the battery powder is added to an acidic leaching solution such as sulfuric acid for leaching. The leaching process can be performed by a known method or condition, but it is preferred to set the pH to 0.0 to 2.0 and the oxidation-reduction potential (ORP value, silver / silver chloride potential reference) to 0 mV or less.

[0033] It should be noted that, as required, the battery powder may be contacted with water in advance before leaching with the acidic leaching solution to separate only the lithium contained in the lithium ion battery waste. In this case, the water leaching residue after leaching lithium by contacting the battery powder with water is added to the acidic leaching solution to perform acid leaching.

[0034] A post-leaching solution in which a specified metal is dissolved is obtained by acid leaching. The specified metals mentioned here include cobalt, nickel, manganese, and aluminum. The specified metals sometimes also include lithium, iron, etc. It should be noted that sometimes the copper contained in the battery powder is not dissolved by acid leaching, but can remain in the acid leaching residue for removal. It should be noted that in the case where copper is leached and dissolved in the post-leaching solution, a process of removing copper by electrolysis can also be performed before the neutralization process described later.

[0035] For example, the cobalt concentration in the leached solution may be 0 g / L to 50 g / L, the nickel concentration may be 0 g / L to 50 g / L, the manganese concentration may be 1 g / L to 50 g / L, the aluminum concentration may be 0.010 g / L to 10 g / L, and the iron concentration may be 0.1 g / L to 5 g / L. The lithium concentration may be 0 g / L to 7.0 g / L, for example. The calcium concentration may be 0 g / L to 1.0 g / L, for example.

[0036] (Neutralization process)

[0037] Next, the post-leaching liquid can be subjected to a neutralization step. In the neutralization step, first, an alkali such as sodium hydroxide is added to the post-leaching liquid to neutralize it in a manner to achieve a predetermined pH. As a result, part of the aluminum dissolved in the post-leaching liquid is precipitated. Then, by solid-liquid separation using a filter press, a concentrator, or the like, the residue containing part of the aluminum can be removed.

[0038] Here, it is more preferable to adjust the pH to 4.0 to 6.0 by adding an alkali. In addition, the oxidation-reduction potential (ORPvsAg / AgCl) of the post-leaching solution is preferably -500 mV to 100 mV. The liquid temperature is preferably 50°C to 90°C.

[0039] After that, an oxidant is added and the pH is adjusted to a range of 3.0 to 4.0, thereby precipitating the iron in the liquid. The addition of the oxidant oxidizes the iron in the liquid from divalent to trivalent, and the trivalent iron precipitates as an oxide or hydroxide at a lower pH than the divalent iron. In most cases, the iron precipitates as a solid such as iron hydroxide (Fe(OH)3). The precipitated iron can be removed by solid-liquid separation.

[0040] In order to precipitate iron, the ORP value during oxidation is preferably set to 300 mV to 900 mV. In addition, before adding the oxidizing agent, in order to lower the pH, for example, an acid such as sulfuric acid, hydrochloric acid, or nitric acid may be added.

[0041] The oxidant is not particularly limited as long as it can oxidize iron, and for example, manganese dioxide can be used. The manganese dioxide used as the oxidant may be a reagent, or may be a positive electrode active material containing manganese dioxide or a manganese-containing leaching residue obtained by leaching the positive electrode active material.

[0042] After the addition of the oxidizing agent, a base such as sodium hydroxide, sodium carbonate, or ammonia may be added to adjust the pH to a predetermined range.

[0043] After the neutralization step, an acidic solution as a neutralized solution is obtained. The acidic solution contains at least cobalt ions and / or nickel ions, manganese ions and aluminum ions. The acidic solution sometimes also contains one or more metal ions selected from the group consisting of magnesium ions, sodium ions, lithium ions and calcium ions.

[0044] For example, the cobalt concentration in the acidic solution is sometimes 0 g / L to 50 g / L, the nickel concentration is 0 g / L to 50 g / L, and the manganese concentration is 1 g / L to 50 g / L. The aluminum concentration is preferably 0.010 g / L to 1 g / L, and more preferably 0.010 g / L to 0.5 g / L. The magnesium concentration is sometimes, for example, 0 g / L to 0.1 g / L. The sodium concentration is sometimes, for example, 0 g / L to 40 g / L. The lithium concentration is sometimes, for example, 0 g / L to 7.0 g / L. The calcium concentration is sometimes, for example, 0 g / L to 1.0 g / L.

[0045] (Al removal process)

[0046] After the neutralization step, an Al removal step is performed to extract the aluminum ions in the above-mentioned acidic solution into a solvent to remove them. Here, the manganese ions in the acidic solution remain in the extract residue (aqueous phase), and the aluminum ions are extracted into the solvent (organic phase). Thus, the aluminum ions are removed to obtain an extract residue containing at least cobalt ions and / or nickel ions, and manganese ions. Here, the content of cobalt ions and / or nickel ions, and the content of manganese ions in the extract residue obtained after the Al removal step are preferably 80% or more of the content of each ion in the neutralized solution (acidic solution) on a mass basis, and more preferably 90% or more.

[0047] In the Al removal step, if aluminum ions are extracted while manganese ions are hardly extracted, various extractants such as phosphate-based extractants and carboxylic acid-based extractants can be used, and an appropriate equilibrium pH can be set accordingly during extraction.

[0048] Examples of carboxylic acid extractants that can be used in the Al removal process include neodecanoic acid and cyclohexanecarboxylic acid. Among them, neodecanoic acid is preferred from the viewpoint of extracting aluminum ions without extracting manganese ions as much as possible. The carboxylic acid extractant preferably contains a carboxylic acid having 8 to 16 carbon atoms. Specifically, Versatic Acid 10 (also referred to as "VA-10") manufactured by Shell Chemical Company can be used. In this case, the equilibrium pH during extraction is preferably set to 4.0 to 5.0, and more preferably to 4.3 to 4.7. At an equilibrium pH that is too low, there is a possibility that aluminum ions are not fully extracted into the solvent and remain in the acidic solution in large quantities. On the other hand, at an equilibrium pH that is too high, aluminum is oxidized to form solid aluminum hydroxide, which cannot be extracted by the solvent. In addition, if the equilibrium pH can be extracted from Figure 2 As known, cobalt ions, nickel ions, and manganese ions may be extracted into the solvent. If a solvent containing a carboxylic acid extractant is used and the equilibrium pH is set as described above, almost all aluminum ions can be removed, while most of the cobalt ions and / or nickel ions and manganese ions remain in the extract residue (aqueous phase). Here, Figure 2 This is a graph obtained by plotting the extraction rates of each metal obtained in each of these extraction tests (calculated based on the amount of each metal in the acidic solution of Table 1 and the amount of each metal remaining in the extract residue) by performing a plurality of extraction tests under different conditions in which the equilibrium pH was changed within the range of pH 3.0 to pH 7.5 using a solvent containing VA-10 as an extractant for the acidic solution of the composition shown in Table 1.

[0049] [Table 1]

[0050] Ni Co Mn Mg Ca Al Concentration (g / L) 31.36 9.98 10.38 0.0164 0.45 0.49

[0051] When an extractant is used, the solvent is typically obtained by diluting a hydrocarbon-based organic solvent. Examples of organic solvents include aromatics, paraffins, and cycloparaffins. For example, the concentration of a phosphate-based extractant in a solvent is sometimes set to 20% to 30% by volume, and the concentration of a carboxylic acid-based extractant in a solvent is sometimes set to 20% to 30% by volume. However, this is not limited to this. It should be noted that the O / A ratio is sometimes set to 1.0 to 5.0.

[0052] The above-mentioned extraction can be carried out based on the usual method. As one example, a solution (aqueous phase) is brought into contact with a solvent (organic phase), and they are typically stirred and mixed by a mixer for, for example, 5 to 60 minutes, so that the ions react with the extractant. The temperature during extraction is set to room temperature (about 15 to 25°C) to below 60°C, and is preferably implemented at 35 to 45°C for reasons of extraction speed, phase separation, and evaporation of the organic solvent. Thereafter, the mixed organic phase and aqueous phase are separated by a settling vessel using a difference in specific gravity. The extraction of the metal extraction step described later can also be implemented in the same manner.

[0053] In the raffinate obtained after the Al removal step as described above, for example, the cobalt concentration is 0 g / L to 50 g / L, the nickel concentration is 0 g / L to 50 g / L, the manganese concentration is 1 g / L to 50 g / L, and the aluminum concentration is 0.001 g / L or less.

[0054] (Metal Extraction Process)

[0055] The raffinate after the Al removal step is subjected to a metal extraction step of extracting and stripping two or three metal ions of cobalt ions and / or nickel ions and manganese ions contained therein. Thus, impurities such as sodium ions, calcium ions, lithium ions, and magnesium ions that may be contained in the raffinate are left in the aqueous phase and separated from the two or three metal ions, thereby obtaining a metal mixed solution as a stripped solution containing the two or three metal ions.

[0056] In the metal extraction step, in order to extract the above three metal ions, a solvent containing a carboxylic acid extractant is used, and the equilibrium pH is set to 6.5 to 7.5. If the equilibrium pH is within this range, then according to Figure 2 The exemplified extraction curve shows that cobalt ions and / or nickel ions and manganese ions can be extracted efficiently, and impurities can be left in the aqueous phase. The equilibrium pH is more preferably set to 6.8 to 7.2.

[0057] The carboxylic acid extractant may be cyclohexane acid or the like as described above, but preferably contains neodecanoic acid, and preferably contains a carboxylic acid having 8 to 16 carbon atoms, and particularly preferably VA-10. When a carboxylic acid extractant containing neodecanoic acid is used, cobalt ions and / or nickel ions, and manganese ions can be effectively extracted without extracting other metal ions.

[0058] The carboxylic acid extractant can be diluted with an organic solvent such as an aromatic, paraffin, or cycloalkane to form a solvent. The concentration of the carboxylic acid extractant in the solvent is preferably set to 20% to 30% by volume. As a result, most of the impurities can remain in the aqueous phase, while manganese ions, cobalt ions, and / or nickel ions can be fully extracted. The O / A ratio is preferably set to 1.0 to 1.5. If the O / A ratio is within this range, impurities are hardly extracted, while manganese ions, cobalt ions, and / or nickel ions are fully extracted.

[0059] After the cobalt ions and / or nickel ions and manganese ions are extracted into the solvent, the solvent is stripped to transfer the cobalt ions and / or nickel ions and manganese ions to the aqueous phase. Specifically, the solvent is mixed with a stripping solution such as sulfuric acid or hydrochloric acid, and stirred for 5 to 60 minutes by a mixer or the like. As the stripping solution, sulfuric acid is preferably used. In the case of using a stripping solution of sulfuric acid, the stripping solution, i.e., the metal mixed solution, becomes a sulfuric acid solution. In order to effectively strip the manganese ions, cobalt ions and / or nickel ions in the solvent, the acid concentration of the stripping solution is preferably adjusted to 0.05 g / L to 200 g / L (pH: -0.6 to 3.0), and more preferably adjusted to 1.5 g / L to 15 g / L (pH: 0.5 to 1.5). The stripping temperature can be set to room temperature to below 60°C, and is preferably implemented at 35 to 45°C for the reasons of stripping speed, phase separation, and evaporation of the organic solvent.

[0060] The metal mixed solution contains cobalt ions and / or nickel ions, and manganese ions. For example, the cobalt concentration in the stripped solution is sometimes 0 g / L to 50 g / L, the nickel concentration is 0 g / L to 50 g / L, and the manganese concentration is 1 g / L to 50 g / L. The stripped solution sometimes contains sodium, calcium, and magnesium as impurities, but the total concentration of the impurities is preferably 1.0 g / L or less.

[0061] (Precipitation process)

[0062] In the precipitation step, a mixed metal salt containing metal salts of cobalt and / or nickel and manganese is precipitated from the metal mixed solution (strip extraction solution) obtained in the above-mentioned metal extraction step.

[0063] Here, for example, a base such as sodium hydroxide is added to the metal mixed solution to set the pH to 9.0 to 10.0, so that cobalt and / or nickel and manganese are precipitated. The ORP value (silver / silver chloride potential reference) at this time can be set to, for example, 0 mV to 600 mV. The liquid temperature can be set to 60°C to 90°C.

[0064] The mixed metal salt as the neutralization residue obtained by the subsequent solid-liquid separation may contain metal salts of cobalt and / or nickel and manganese, such as cobalt hydroxide and / or nickel hydroxide and manganese hydroxide, etc. In addition, the neutralization residue may contain oxides of each metal, such as Co3O4, Mn3O4, Mn2O3, Ni3O4, etc.

[0065] It should be noted that, if necessary, the neutralization residue may be washed with water or the like, dissolved in a sulfuric acid solution, and heated and concentrated or cooled to obtain a mixed metal salt containing cobalt sulfate and / or nickel sulfate and manganese sulfate.

[0066] In the mixed metal salts such as the above-mentioned hydroxides or sulfates containing cobalt and / or nickel and manganese, for example, the content of cobalt is 0% to 60% by mass, the content of nickel is 0% to 60% by mass, and the content of manganese is 1% to 60% by mass. In addition, in the mixed metal salt, the content of sodium as an impurity is preferably 60 ppm by mass or less, the content of calcium is 10 ppm by mass or less, and the content of magnesium is 10 ppm by mass or less.

[0067] The mixed metal salt described above can be easily recovered at a low cost compared to the individual metals of cobalt, nickel, and manganese, and can be suitably used in the production of lithium-ion batteries.

[0068] Example

[0069] Next, the above-mentioned method for producing a mixed metal salt was experimentally carried out, and thus the method will be described below. However, the description here is for the purpose of illustration only and is not intended to be limiting.

[0070] (Example 1)

[0071] For 43.4 mL of the acidic solution of the composition shown in Table 2, 217 mL of a solvent containing VA-10 (extraction solvent S1) was used as an extractant and the equilibrium pH was set to 5.0, and aluminum was extracted and removed. The concentration of VA-10 in the solvent was set to 25%, and the O / A ratio was set to 1.0. Here, most of the nickel ions, cobalt ions, and manganese ions were not extracted, and most of the aluminum ions were extracted. The extraction rates calculated based on the concentrations of each metal in the acidic solution and the concentrations of each metal in the extraction residue (extraction residue L1), as well as the contents of each metal in the acidic solution and the contents of each metal in the extraction residue (extraction residue L1) are shown in Table 2. Aluminum ions were extracted 100%. On the other hand, the extraction rates of nickel ions were 11%, the extraction rates of cobalt ions were 9%, and the extraction rates of manganese ions were 9%, all of which could be maintained at around 10%. It should be noted that in this experiment, a separatory funnel was used for the experiment, but in the operation, by performing the extraction in a multi-stage countercurrent manner, it can be expected that aluminum ions can be extracted without extracting nickel ions, cobalt ions, and manganese ions.

[0072] [Table 2]

[0073]

[0074] For 28.0 mL of the above-mentioned raffinate L1, under the condition that the equilibrium pH is 7.0 using 155 mL of a solvent containing VA-10 (extraction solvent S2) as an extractant, cobalt ions, nickel ions and manganese ions are extracted into the solvent, and other elements remain in the aqueous phase (raffinate L2). The concentration of VA-10 in the solvent is set to 25%, and the O / A ratio is set to 1.0. The concentration of each metal in the raffinate L2, the amount of metal in the solvent calculated based on the content of each metal in the raffinate L1 supplied to the test and the content of each metal in the raffinate L2, and the extraction rate are shown in Table 3. The extraction rate of nickel ions is 100%, the extraction rate of cobalt ions is 100%, and the extraction rate of manganese ions is 99%, and almost all of them can be extracted. On the other hand, with regard to magnesium, 45% can be extracted, and the remaining 55% remains in the aqueous phase.

[0075] [Table 3]

[0076]

[0077] For the 155mL of the above-mentioned extraction solvent S2 after the above-mentioned extraction, 155mL of the stripping solution (O / A ratio = 1) with a sulfuric acid concentration of 1.5g / L and a pH of 1.5 was used for stripping. Thus, a metal mixed solution as a stripping liquid was obtained. The concentration and content of each metal in the metal mixed solution (stripping liquid) obtained by the stripping are shown in Table 4. As a result, nickel ions, cobalt ions, and manganese ions can be recovered in their entirety to the aqueous phase by stripping, while magnesium can remain in the solvent without being stripped.

[0078] [Table 4]

[0079]

[0080] According to the above results, by treating the acidic solution in the above steps, all aluminum contained in the acidic solution is removed, and about 90% of nickel ions, cobalt ions, and manganese ions can be recovered in the metal mixed solution.

Claims

1. A method for producing a metal mixed solution, which is a method for producing a metal mixed solution containing at least one of cobalt ions and nickel ions and manganese ions, wherein: The method for preparing the metal mixed solution comprises: an Al removal step, in which the battery powder of the lithium ion battery waste is subjected to a leaching step to obtain an acidic solution containing at least one of cobalt ions and nickel ions, manganese ions and aluminum ions, while leaving at least a portion of the manganese ions in the acidic solution in an aqueous phase and removing the aluminum ions by extracting them into a solvent; and a metal extraction step, in which the raffinate obtained in the Al removal step is subjected to an equilibrium pH of 6.5 to 7.5 using a solvent containing a carboxylic acid extractant, and cobalt ions and at least one of nickel ions and manganese ions in the raffinate are extracted into the solvent, and then the cobalt ions and at least one of nickel ions and manganese ions are stripped from the solvent to obtain a metal mixed solution containing at least one of cobalt ions and nickel ions and manganese ions as a stripped liquid, In the Al removal step, a solvent containing a carboxylic acid extractant is used to adjust the equilibrium pH to 4.0 to 5.

0. In the Al removal step, at least 80% by mass of the manganese ions and at least 80% by mass of at least one of the cobalt ions and the nickel ions in the acidic solution remain in the aqueous phase.

2. The method for producing a metal mixed solution according to claim 1, wherein: In the metal extraction step, the carboxylic acid-based extractant contained in the solvent includes neodecanoic acid.

3. A method for producing a mixed metal salt, which is a method for producing a mixed metal salt containing a metal salt of manganese and a metal salt of at least one of cobalt and nickel, wherein: The method for preparing the mixed metal salt comprises: A precipitation step in which a mixed metal salt containing a metal salt of manganese and a metal salt of at least one of cobalt and nickel is precipitated from the metal mixed solution obtained by the method for producing a metal mixed solution according to claim 1 or 2.

4. The method for producing a mixed metal salt according to claim 3, wherein: In the precipitation step, the metal mixed solution is neutralized with sodium hydroxide to precipitate a mixed metal salt including at least one of cobalt hydroxide and nickel hydroxide and manganese hydroxide.

5. The method for producing a mixed metal salt according to claim 3 or 4, wherein: The mixed metal salt is used in the manufacture of lithium ion batteries.

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