Metal separation methods

Abstract

To provide a metal separation method that can efficiently separate and / or recover a metal which is desired to be separated and / or recovered, from an aqueous solution containing the metal.SOLUTION: The metal separation method is provided that includes a process of bringing the aqueous solution containing the metal into contact with a metal separation agent which contains a salt represented by the following formula (I) (component A), thiocyanic acid (component B) and a water-insoluble organic solvent (component C), and separating the metal from an aqueous phase to an organic phase. In the formula (I), R1 is a hydrocarbon group which has 6 or more and 22 or less carbon atoms, and may have an ester group, an amide group and / or an ether group; R2 and R3 are each independently a hydrocarbon group which has 6 or more and 22 or less carbon atoms and may have an ester group, an amide group and / or an ether group, or an alkyl group which has 1 or more and 4 or less carbon atoms and may have a hydroxyl group; R4 is an alkyl group having 1 or more and 6 or less carbon atoms, or a hydrogen atom; and X- is an anion.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a metal separation method for separating or separating and recovering a metal from an aqueous solution containing the metal, a metal separator kit, a metal recovery method, a method for producing a lithium ion battery, and a metal separator. [Background technology]

[0002] Rare and precious metals are important metals due to their widespread use in commerce and industry. However, efficient recycling processes for these metals in industrial products must be developed to avoid the discharge of hazardous residues. Metal recovery from e-waste and natural resources is typically achieved by applying pyrometallurgical and hydrometallurgical processes. However, pyrometallurgical methods consume large amounts of energy and generate polluting gases during the process, which can be highly damaging to humans and the environment. Hydrometallurgical methods involve dissolving the desired metals through alkaline or acid leaching. After the leaching process, the resulting metal solution is subjected to further separation processes such as chemical precipitation, solvent extraction, and electrolytic deposition. Among these, solvent extraction is the most efficient and commonly used method. Solvent extraction uses a metal capture agent (metal separator) to capture the metals in the aqueous solution. Nitrogen-containing compounds such as amine compounds are commonly used as metal capture agents.

[0003] For example, Patent Document 1 discloses a technique for extracting cobalt using a tertiary amine as an extractant and an aromatic hydrocarbon solvent as a diluent in order to separate and recover cobalt from a cobalt-containing aqueous nickel chloride solution in the production of metallic nickel and metallic cobalt by a hydrometallurgical process. In the examples, tri-normal octylamine is used as the tertiary amine.

[0004] Patent Document 2 discloses a solvent extraction method for extracting cobalt from an aqueous solution containing cobalt ions, in which the solubility of a quaternary ammonium ionic liquid in water is significantly reduced by mixing it with a certain organic solvent, and the quaternary ammonium ionic liquid is used as an extractant to extract ions from the aqueous solution containing cobalt. In the examples, trioctylmethylammonium chloride is used. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-183282 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-168858 Summary of the Invention [Problem to be solved by the invention]

[0006] However, alkylammonium salts such as trioctylmethylammonium chloride tend to exhibit poor cobalt separation and recovery performance when the hydrochloric acid concentration is low or in the presence of sulfate ions. High-concentration hydrochloric acid also places a heavy burden on the environment and is difficult to dispose of. Furthermore, the change in separation and recovery performance depending on the type of acid present reduces the versatility of the extractant.

[0007] Therefore, the present disclosure provides a metal separation method that can efficiently separate and / or recover a metal to be separated and / or recovered from an aqueous solution containing the metal. [Means for solving the problem]

[0008] In one aspect, the present disclosure relates to a metal separation method for separating or separating and recovering a metal from an aqueous solution containing the metal, the metal separation method comprising the step of contacting the aqueous solution containing the metal with a metal separating agent comprising a salt represented by the following formula (I) (component A), thiocyanic acid (component B), and a water-insoluble organic solvent (component C), and separating the metal from the aqueous phase into an organic phase. [ka] In formula (I), R 1 is a hydrocarbon group having 6 to 22 carbon atoms which may have an ester group, an amide group, and / or an ether group, and R 2 and R 3 are each independently a hydrocarbon group having 6 to 22 carbon atoms which may have an ester group, an amide group and / or an ether group, or an alkyl group having 1 to 4 carbon atoms which may have a hydroxyl group, and R 4 is an alkyl group having 1 to 6 carbon atoms or a hydrogen atom, and X - is an anion.

[0009] In one aspect, the present disclosure relates to a metal separating agent kit for separating or separating and recovering a metal from an aqueous solution containing the metal, the metal separating agent kit comprising a first agent containing a salt represented by the following formula (I) (component A) and a second agent containing thiocyanic acid (component B): [ka] In formula (I), R 1 is a hydrocarbon group having 6 to 22 carbon atoms which may have an ester group, an amide group, and / or an ether group, and R 2 and R 3 are each independently a hydrocarbon group having 6 to 22 carbon atoms which may have an ester group, an amide group and / or an ether group, or an alkyl group having 1 to 4 carbon atoms which may have a hydroxyl group, and R 4 is an alkyl group having 1 to 6 carbon atoms or a hydrogen atom, and X - is an anion.

[0010] In one aspect, the present disclosure relates to a metal recovery method for separating and recovering metals from an aqueous solution containing the metal, the method including the steps of contacting the aqueous solution containing the metal with an agent comprising the metal separating agent kit of the present disclosure to separate the metal from the aqueous phase into an organic phase, and recovering the metal from the organic phase.

[0011] In one aspect, the present disclosure relates to a method for manufacturing a lithium ion battery, comprising the steps of contacting an aqueous solution containing a metal with an agent comprising the metal separating agent kit of the present disclosure to separate the metal from the aqueous phase into an organic phase, recovering the metal from the organic phase, and manufacturing a battery using the metal recovered in the above step.

[0012] In one aspect, the present disclosure relates to a metal separating agent for separating or separating and recovering a metal from an aqueous solution containing the metal, the metal separating agent comprising a salt represented by the following formula (I) (component A) and thiocyanic acid (component B): In one aspect, the present disclosure relates to a metal separating agent for separating or separating and recovering metals from an aqueous solution containing the metal, the metal separating agent comprising a salt represented by the following formula (I) (component A) and thiocyanic acid (component B): [ka] In formula (I), R 1 is a hydrocarbon group having 6 to 22 carbon atoms which may have an ester group, an amide group, and / or an ether group, and R 2 and R 3 are each independently a hydrocarbon group having 6 to 22 carbon atoms which may have an ester group, an amide group and / or an ether group, or an alkyl group having 1 to 4 carbon atoms which may have a hydroxyl group, and R 4 is an alkyl group having 1 to 6 carbon atoms or a hydrogen atom, and X - is an anion.

[0013] In one aspect, the present disclosure relates to a metal separation method for separating a metal from an aqueous solution containing the metal, the metal separation method comprising the step of contacting the aqueous solution containing the metal with the metal separating agent of the present disclosure and separating the metal from the aqueous phase into an organic phase.

[0014] In one aspect, the present disclosure relates to a metal recovery method for separating and recovering metals from an aqueous solution containing the metals, the method including the steps of contacting the aqueous solution containing the metals with the metal separating agent of the present disclosure to separate the metals from the aqueous phase into an organic phase, and recovering the metals from the organic phase. [Effects of the Invention]

[0015] According to one aspect of the present disclosure, a metal separation method can be provided that can efficiently separate and / or recover a metal to be separated and / or recovered from an aqueous solution containing the metal. DETAILED DESCRIPTION OF THE INVENTION

[0016] [Metal separation method] The present disclosure is based on the finding that by using a metal separating agent containing a salt represented by the above formula (I) (component A), thiocyanic acid (component B) and a water-insoluble organic solvent (component C), or a metal separating agent containing a salt represented by the above formula (I) (component A) and thiocyanic acid (component B), it is possible to efficiently separate and / or recover a metal to be separated and / or recovered from an aqueous solution containing the metal.

[0017] That is, in one aspect, the present disclosure relates to a metal separation method for separating or separating and recovering a metal from an aqueous solution containing the metal, the metal separation method (hereinafter also referred to as the "metal separation method of the present disclosure") comprising a step (hereinafter also referred to as the "contact step") of contacting the aqueous solution containing the metal with a metal separating agent (hereinafter also referred to as the "metal separating agent of the present disclosure") comprising a salt represented by the above formula (I) (component A), thiocyanic acid (component B), and a water-insoluble organic solvent (component C) to separate the metal from the aqueous phase into an organic phase. In one or more embodiments, the metal separation method of the present disclosure can provide a metal separation method that can efficiently separate and / or recover a metal to be separated and / or recovered from an aqueous solution containing the metal.In one or more embodiments, the metal separation method of the present disclosure can provide a metal separation method that has excellent performance for separating and recovering metals from an aqueous solution containing the metal.

[0018] In another aspect, the present disclosure relates to a metal separation method for separating a metal from an aqueous solution containing the metal, the metal separation method comprising a step (hereinafter also referred to as the "metal separation method of the present disclosure") of contacting the aqueous solution containing the metal with a metal separating agent (hereinafter also referred to as the "metal separating agent of the present disclosure") comprising a salt represented by the above formula (I) (component A) and thiocyanic acid (component B) to separate the metal from the aqueous phase into an organic phase (hereinafter also referred to as the "contacting step"). According to the metal separation method of the present disclosure, it is possible to efficiently separate a desired metal from an aqueous solution containing the metal.

[0019] In one or more embodiments, the metal separation method of the present disclosure is excellent in cobalt recovery efficiency. Furthermore, in one or more embodiments, the metal separation method of the present disclosure is excellent in Co-Ni separation ability. That is, in one or more embodiments, the metal separation method of the present disclosure is a metal separation method for separating cobalt from an aqueous solution containing cobalt, or for separating and recovering cobalt. In one or more embodiments, the metal separation method of the present disclosure is a metal separation method for separating cobalt from an aqueous solution containing cobalt and nickel, or for separating and recovering cobalt.

[0020] Although the details of the mechanism of action by which the effects of the present disclosure are manifested are still unclear, it is speculated as follows. In an aqueous solution (aqueous phase), metal ions are stabilized by primarily accepting electrons from water molecules or other hydrophilic compounds. This stabilized structure is called a metal ion cluster. In order for a metal ion cluster to migrate into oil (organic phase), it must be more stabilized. Because the salt represented by formula (I) (Component A) in this disclosure is positively charged with a high charge density, electrostatic interactions occur with negatively charged metal ion clusters in the aqueous solution (aqueous phase), enabling the formation of a more stabilized structure. Therefore, Component A in this disclosure exhibits a certain effect as a metal separating agent for oil (organic phase). Furthermore, when used in combination with thiocyanate (component B), component B forms complexes with each metal that have unique structures compared to general ligands. For example, it is said to form a linear bidentate complex with nickel and a tetrahedral tetradentate complex with cobalt. The difference in the structure of this thiocyanate complex creates differences in the reactivity of component A with each metal, which is thought to enable more precise metal separation. In the present disclosure, the presence of component B in the oil (organic phase) traps metal ions in the oil (organic phase), and component A contributes to the stable presence of component B in the oil (organic phase) with the metal ions that have interacted in the oil (organic phase), and it is believed that specific metal ions can be extracted much more efficiently than when the salt represented by formula (I) (component A) or thiocyanic acid (component B) is used alone. The salt represented by formula (I) (Component A) in the present disclosure may be an alkylammonium salt or amine salt having a polar group such as an ester group. When the alkylammonium salt or amine salt has a polar group, its electron-withdrawing properties are thought to enable it to share electrons with the metal ion and form a more stable covalent bond. The rate of formation of this covalent bond differs for each type of metal ion, which is thought to improve selectivity and enable separation of negatively charged metal ion clusters. Therefore, when Component A in the present disclosure has a polar group (specific alkylammonium salt or amine salt), it is thought to be able to provide better metal separation and recovery capabilities. However, the present disclosure need not be construed as being limited to the above mechanism.

[0021] <Aqueous solution containing metal> In one or more embodiments, the "metal-containing aqueous solution" in the present disclosure may be obtained by treating electronic waste. In one or more embodiments, the electronic waste may be waste from electronic components such as lithium-ion batteries. In one or more embodiments, the metal-containing aqueous solution may be an aqueous solution (leachate) obtained by treating electronic component waste with acid. A "metal-containing aqueous solution" obtained from electronic waste can be obtained, for example, by separating the positive electrode components of a lithium-ion battery into iron-based metals, plastics, electrode powder BM (black matrix), etc. by crushing or heat treatment, and then dissolving the electrode powder BM in a sulfuric acid or hydrochloric acid solution to form an acidic aqueous solution. Electrode powder BM contains, for example, lithium (Li), cobalt (Co), nickel (Ni), manganese (Mn), etc. In one or more embodiments, the metal-containing aqueous solution can be an aqueous solution containing cobalt or an aqueous solution containing cobalt and nickel. In the present disclosure, an example of an aqueous solution containing a metal is a leachate obtained by leaching battery sludge containing a positive electrode active material of a lithium ion battery with an acidic aqueous solution.

[0022] <Contact process> In one or more embodiments, the contacting step is a step of separating the metal from the aqueous phase by contacting an aqueous solution containing the metal, which is the aqueous phase, with the organic phase of the metal separating agent of the present disclosure, and distributing (extracting) the metal to be separated into the organic phase. The organic phase used in the above process may be contained in an oil-continuous or bicontinuous emulsion system. In one or more embodiments, the metal separating agent of the present disclosure containing an organic phase is in a form containing a water-insoluble organic solvent (component C) described below. The procedure for the contact step is not particularly limited, and any known procedure used in liquid-phase extraction can be appropriately selected. For example, an aqueous solution containing a metal, which is an aqueous phase, and the metal separating agent of the present disclosure, which is an organic phase, can be placed in a container, and the aqueous and organic phases can be thoroughly mixed using a shaker or the like, followed by phase separation by centrifugation to perform liquid separation. Alternatively, known extraction devices or extraction tools, such as an extraction device such as a countercurrent extraction device or a separating funnel, can be used instead of the container.

[0023] The pH of the metal-containing aqueous solution is not particularly limited and can be appropriately selected depending on the type and purpose of the metal to be separated and / or recovered. In one or more embodiments, the pH of the metal-containing aqueous solution is typically 6.0 or less, preferably 5.5 or less, and more preferably 5.0 or less or 5 or less. For example, when the metal to be separated and / or recovered is cobalt (Co), the pH of the metal-containing aqueous solution is preferably 7.0 or less or 7 or less, and more preferably 4.0 or less or 4 or less. In the present disclosure, the pH of the aqueous solution is a value at 25°C and can be measured using a pH meter, specifically, by the method described in the Examples.

[0024] In the contacting step, the time for which the aqueous phase and the organic phase are brought into contact with each other is not particularly limited and can be appropriately selected depending on the purpose. The time for the contacting is, for example, 1 to 10 minutes.

[0025] In the contact step, the temperature at which the aqueous phase and the organic phase are brought into contact is not particularly limited, but from the viewpoint of the solubility of the metal separating agent, it is preferably 0° C. or higher, more preferably 10° C. or higher, and even more preferably 20° C. or higher, and from the viewpoint of handleability, it is preferably 100° C. or lower, more preferably 75° C. or lower, and even more preferably 50° C. or lower. More specifically, the temperature in the contact step is preferably 0° C. or higher and 100° C. or lower, more preferably 10° C. or higher and 75° C. or lower, and even more preferably 20° C. or higher and 50° C. or lower.

[0026] In one or more embodiments, the metal separating agent of the present disclosure that is brought into contact with the aqueous phase in the contacting step includes an organic phase, which in one or more embodiments is derived from the water-insoluble organic solvent (component C) of the metal separating agent of the present disclosure.

[0027] In the contacting step, the volume ratio of the aqueous phase to the organic phase to be contacted (aqueous phase volume / organic phase volume) is not particularly limited and can be appropriately selected depending on the purpose. It is usually 1 or more, and preferably 1 to 10.

[0028] The amount (mol%) of the salt represented by formula (I) (component A) in the metal separating agent of the present disclosure to be contacted with the aqueous phase in the contact step is, from the viewpoint of the separability of the metal to be separated, preferably 100 mol% or more, more preferably 500 mol% or more, even more preferably 1000 mol% or more, and preferably 10,000 mol% or less, more preferably 5,000 mol% or less, and even more preferably 2,500 mol% or less, relative to the metal concentration (100 mol%) in the aqueous solution containing the metal. More specifically, the amount of the salt represented by formula (I) (component A) in the metal separating agent of the present disclosure is preferably 100 mol% or more and 10,000 mol% or less, more preferably 500 mol% or more and 5,000 mol% or less, and even more preferably 1,000 mol% or more and 2,500 mol% or less, relative to the metal concentration (100 mol%) in the aqueous solution containing the metal.

[0029] The amount of thiocyanate (component B) in the metal separating agent of the present disclosure that is contacted with the aqueous phase in the contact step is, from the viewpoint of the separability of the metal to be separated, preferably 100 mol% or more, more preferably 500 mol% or more, even more preferably 1000 mol% or more, and preferably 20,000 mol% or less, more preferably 10,000 mol% or less, and even more preferably 5,000 mol% or less, relative to the metal concentration (100 mol%) in the metal-containing aqueous solution. More specifically, the amount of thiocyanate (component B) in the metal separating agent of the present disclosure is preferably 100 mol% or more and 20,000 mol% or less, more preferably 500 mol% or more and 10,000 mol% or less, and even more preferably 1,000 mol% or more and 5,000 mol% or less, relative to the metal concentration (100 mol%) in the metal-containing aqueous solution.

[0030] The amount of the water-insoluble organic solvent (component C) in the metal separating agent of the present disclosure that is contacted with the aqueous phase in the contact step is, from the viewpoint of recovery efficiency of the metal to be recovered, preferably 1000 mol% or more, more preferably 5000 mol% or more, even more preferably 10,000 mol% or more, and preferably 100,000 mol% or less, more preferably 50,000 mol% or less, and even more preferably 25,000 mol% or less, relative to the metal concentration (100 mol%) in the metal-containing aqueous solution. More specifically, the amount of the water-insoluble organic solvent (component C) in the metal separating agent of the present disclosure is preferably 1000 mol% to 100,000 mol%, more preferably 5000 mol% to 50,000 mol%, and even more preferably 10,000 mol% to 25,000 mol% relative to the metal concentration (100 mol%) in the metal-containing aqueous solution.

[0031] [Metal separation agent] In one aspect, the present disclosure relates to a metal separating agent for separating or separating and recovering a metal from an aqueous solution containing the metal, the metal separating agent comprising a salt represented by the above formula (I) (component A) and thiocyanic acid (component B) (hereinafter also referred to as the "metal separating agent of the present disclosure").

[0032] According to one or more embodiments of the present disclosure, a metal separating agent capable of efficiently separating and / or recovering a metal to be separated and / or recovered from an aqueous solution containing the metal can be provided. According to one or more embodiments of the present disclosure, a metal separating agent having excellent performance for separating and recovering metals from an aqueous solution containing the metal can be provided.

[0033] In one or more embodiments, the metal separating agent of the present disclosure is used to separate or separate and recover metals from an aqueous solution containing the metal. In one or more embodiments, the metal to be separated and / or recovered includes a catalytic metal for lithium-ion batteries and the like. Examples of catalytic metals include fourth period metals, such as at least one metal selected from cobalt, nickel, and manganese. The metal in the aqueous solution is preferably in an ionic state. In particular, in one or more embodiments, the metal separating agent of the present disclosure has excellent cobalt recovery efficiency. Furthermore, in one or more other embodiments, the metal separating agent of the present disclosure has excellent Co-Ni separation ability. That is, in one or more embodiments, the metal separating agent of the present disclosure is a metal separating agent for separating or separating and recovering cobalt from an aqueous solution containing cobalt. In one or more embodiments, the metal separating agent of the present disclosure is a metal separating agent for separating or separating and recovering cobalt from an aqueous solution containing cobalt and nickel.

[0034] <Component A: Salt represented by formula (I)> The metal separating agent of the present disclosure contains a salt represented by the following formula (I) (hereinafter also referred to as "component A"). 4 When R is an alkyl group having 1 to 6 carbon atoms, component A is a quaternary ammonium salt. 4 is a hydrogen atom, Component A is a tertiary amine salt. That is, Component A is a salt represented by formula (I) and includes a quaternary ammonium salt and a tertiary amine salt. Component A may be one type or a combination of two or more types. [ka]

[0035] In formula (I), R 1 is a hydrocarbon group having 6 to 22 carbon atoms which may have an ester group, an amide group, and / or an ether group, and R 2 and R 3 are each independently a hydrocarbon group having 6 to 22 carbon atoms which may have an ester group, an amide group and / or an ether group, or an alkyl group having 1 to 4 carbon atoms which may have a hydroxyl group, and R 4 is an alkyl group having 1 to 6 carbon atoms or a hydrogen atom, and X - is an anion.

[0036] In the above formula (I), R 1 , R 2 and R 3 are each independently a hydrocarbon group having 6 to 22 carbon atoms which may have an ester group, an amide group, and / or an ether group, and R 1 , R 2 and R 3 From the viewpoint of the separability of the metal to be separated, the hydrocarbon group is a hydrocarbon group having 6 to 22 carbon atoms, preferably a hydrocarbon group having 8 to 18 carbon atoms, and more preferably a hydrocarbon group having 8 to 16 carbon atoms. The hydrocarbon group may be a straight chain or a branched chain, but preferably has a branched chain from the viewpoint of suppressing foaming upon contact with an aqueous solution. The hydrocarbon group may be a saturated chain or an unsaturated chain, but preferably has an unsaturated chain from the viewpoint of suppressing foaming upon contact with an aqueous solution. R 1 , R 2 and R 3 From the viewpoint of the separability of the separated metals, at least one of the above preferably has an ester group, an amide group, and / or an ether group, more preferably has an ester group or an ether group, and even more preferably has an ester group. R 1 , R 2 and R 3 In one or more embodiments, when the hydrocarbon group having 6 to 22 carbon atoms has an ester group, an amide group, and / or an ether group, -R 5 -XR6 and R 5 is an alkylene group having 1 to 4 carbon atoms, X is -OC(=O)-, -NH-C(=O)-, or an oxygen atom, and from the viewpoint of the separation ability of the metal to be separated, R 6 R is a hydrocarbon group having 6 to 18 carbon atoms. 5 The number of carbon atoms in R is preferably 1 or 2 from the viewpoint of the separation of the metal to be separated. 6 The number of carbon atoms in R is preferably 6 or more and 18 or less from the viewpoint of the separation of the metal to be separated. 6 The hydrocarbon group may be saturated or unsaturated, but in one or more embodiments, it preferably has an unsaturated chain from the viewpoint of suppressing foaming upon contact with an aqueous solution, and in one or more embodiments, X is preferably —O—C(═O)— from the viewpoint of the separability of the metal to be separated. R 2 and R 3 In terms of the separability of the metal to be separated, the alkyl group having 1 to 4 carbon atoms and optionally having a hydroxyl group is preferably an alkyl group having 1 to 3 carbon atoms and optionally having a hydroxyl group, more preferably an alkyl group having 1 or 2 carbon atoms and optionally having a hydroxyl group, and even more preferably a hydroxyethyl group. R 4 From the viewpoint of the separability of the metal to be separated, the alkyl group is an alkyl group having 1 to 6 carbon atoms or a hydrogen atom, preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, even more preferably an alkyl group having 1 to 2 carbon atoms, and even more preferably a methyl group. X - is a counter ion, and examples thereof include alkyl sulfate ions having 1 to 3 carbon atoms, sulfate ions, phosphate ions, carboxylate ions having 1 to 3 carbon atoms (formate ions, acetate ions, propionate ions), and halide ions. Among these, from the viewpoint of ease of production and availability of raw materials, X - is preferably at least one selected from the group consisting of methyl sulfate ion, ethyl sulfate ion, chloride ion, and bromide ion, and more preferably methyl sulfate ion. -may be one type alone or two or more types.

[0037] In one or more embodiments, component A is R 1 , R 2 and R 3 In one or more embodiments, component A1 is a compound in which at least one of R in formula (I) has an ester group having 6 to 22 carbon atoms (hereinafter also referred to as "component A1"). 1 , R 2 and R 3 a compound in which at least two of R in formula (I) have an ester group having 6 to 22 carbon atoms; 1 , R 2 and R 3 is a compound having an ester group having 6 to 22 carbon atoms. In one or more embodiments, component A1 may be R 1 , R 2 and R 3 are hydrocarbon groups each having 6 to 22 carbon atoms and each having an ester group, 1 and R 2 are hydrocarbon groups each having 6 to 22 carbon atoms and each having an ester group, and R 3 is an alkyl group having 1 to 4 carbon atoms which may have a hydroxyl group, such as methyltris-[ethyl 2-ethylhexyl]-ammonium salt and (2-hydroxyethyl)-methylbis-[ethyl 2-oleate]-ammonium salt. Counter ions of these salts include, for example, methyl sulfate ion, ethyl sulfate ion, chloride ion, bromide ion, etc. Examples of component A1 include methyltris-[ethyl 2-ethylhexyl]-ammonium methyl sulfate and (2-hydroxyethyl)-methylbis-[ethyl 2-oleate]-ammonium methyl sulfate. The number of carbon atoms in the ester group and the hydrocarbon group interrupted by a nitrogen atom is not particularly limited, and may be, for example, 0 or more or 4 or less. In one or more embodiments, component A is R 1 , R 2 and R3 In one or more embodiments, component A2 is a compound in which at least one of the following has an ether group having 6 to 22 carbon atoms (hereinafter also referred to as "component A2"). 1 , R 2 and R 3 is a hydrocarbon group having 6 to 22 carbon atoms and having an ether group, such as tris[2-hexoxyethyl]hexylammonium salt. Counter ions of these salts include, for example, methyl sulfate ion, ethyl sulfate ion, chloride ion, bromide ion, etc. Component A2 includes, for example, tris[2-hexoxyethyl]hexylammonium hydrochloride. The number of carbon atoms in the ether group and the hydrocarbon group interrupted by a nitrogen atom is not particularly limited, but may be, for example, 0 to 4. In one or more embodiments, component A is R 1 , R 2 and R 3 In one or more embodiments, Component A3 is a compound in which at least one of R in Formula (I) has an amide group having 6 to 22 carbon atoms (hereinafter also referred to as "Component A3"). 1 , R 2 and R 3 are hydrocarbon groups each having an amide group and having 6 to 22 carbon atoms, such as tris[2-(oleamido)ethyl]-methyl-ammonium methyl salt. Counter ions of these salts include, for example, methyl sulfate ion, ethyl sulfate ion, chloride ion, bromide ion, etc. Component A3 includes, for example, tris[2-(oleamido)ethyl]-methyl-ammonium methyl sulfate. The number of carbon atoms in the amide group and the hydrocarbon group interrupted by a nitrogen atom is not particularly limited, but may be 0 or more or 4 or less.

[0038] From the viewpoint of the separability of the metal to be separated, component A is preferably at least one selected from component A1, component A2, and component A3, more preferably at least one selected from component A1 and component A2, and even more preferably component A1. From the same viewpoint, component A is preferably at least one selected from methyltris-[ethyl 2-ethylhexylate]-ammonium salt, (2-hydroxyethyl)-methylbis-[ethyl 2-oleate]-ammonium salt, tris[2-hexoxyethyl]-hexyl-ammonium salt, and tris[2-(oleamido)ethyl]-methyl-ammonium methyl salt, and more preferably methyltris-[ethyl 2-ethylhexylate]-ammonium salt, (2-hydroxyethyl)-methylbis-[ethyl 2-oleate]-ammonium salt, At least one selected from methyltris-[ethyl 2-ethylhexyl]-ammonium salt and tris[2-hexoxyethyl]-hexyl-ammonium salt is more preferred, at least one selected from methyltris-[ethyl 2-ethylhexyl]-ammonium salt and (2-hydroxyethyl)-methylbis-[ethyl 2-oleate]-ammonium salt is even more preferred, methyltris-[ethyl 2-ethylhexyl]-ammonium salt is even more preferred, and methyltris-[ethyl 2-ethylhexyl]-ammonium methyl sulfate is even more preferred.

[0039] From the viewpoint of the separability of the metal to be separated, the blending amount (mass%) of component A in the metal separating agent of the present disclosure is preferably 1.0 mass% or more or 1 mass% or more, more preferably 5.0 mass% or more or 5 mass% or more, even more preferably 10.0 mass% or more or 10 mass% or more, and preferably 50 mass% or less, more preferably 40 mass% or less, and even more preferably 30 mass% or less. More specifically, the blending amount (mass%) of component A in the metal separating agent of the present disclosure is preferably 1.0 mass% or more to 50 mass% or 1 mass% or more to 50 mass%, more preferably 5.0 mass% or more to 40 mass% or 5 mass% or more to 40 mass%, and even more preferably 10.0 mass% or more to 30 mass% or 10 mass% or more to 30 mass%. When component A is a combination of two or more types, the blending amount of component A refers to the total blending amount thereof.

[0040] In one or more embodiments, the metal separating agent of the present disclosure is a composition containing component A and component B.

[0041] <Thiocyanate (ingredient B)> In one or more embodiments, the metal separating agent of the present disclosure comprises or contains a blend of component A and a thiocyanate (hereinafter also referred to as "component B") from the viewpoint of the separability of the metal to be separated. That is, in one or more embodiments, the metal separating agent of the present disclosure comprises a blend of component A and a thiocyanate (component B). In one or more embodiments, in the metal separating agent of the present disclosure, component A and component B are present in a miscible state. In the present disclosure, the term "combined" means that not only component A and thiocyanate (component B) but also optional components can be further blended as needed. In the present disclosure, the blending amount of each component in the metal separating agent can be interpreted as the content of each component in the metal separating agent.

[0042] From the viewpoint of the separability of the metal to be separated, examples of component B include ammonium thiocyanate and sodium thiocyanate. Component B may be one type or a combination of two or more types.

[0043] From the viewpoint of the separability of the metal to be separated, the blending amount (mass%) of component B in the metal separating agent of the present disclosure is preferably 0.1 mass% or more, more preferably 0.5 mass% or more, even more preferably 1.0 mass% or more, and is preferably 40 mass% or less, more preferably 20 mass% or less, and even more preferably 10 mass% or less. More specifically, the blending amount (mass%) of component B in the metal separating agent of the present disclosure is preferably 0.1 mass% or more and 40 mass% or less, more preferably 0.5 mass% or more and 20 mass% or less, and even more preferably 0.5 mass% or more and 10 mass% or less, or 1.0 mass% or more and 10 mass% or less. When component B is a combination of two or more types, the blending amount of component B refers to the total blending amount of these.

[0044] The mass ratio A / B of component A to component B in the metal separating agent of the present disclosure (amount of component A blended / amount of component B blended) is preferably 0.01 or more, more preferably 0.1 or more, and even more preferably 1.0 or more, from the viewpoint of the separability of the metal to be separated, and from the same viewpoint, is preferably 50 or less, 40 or less, or 20 or less, more preferably 10 or less, and even more preferably 5.0 or less. More specifically, the mass ratio A / B (amount of component A blended / amount of component B blended) is preferably 0.01 or more and 50 or less, 0.01 or more and 30 or less, or 0.01 or more and 20 or less, more preferably 0.1 or more and 10 or less, and even more preferably 1.0 or more and 5.0 or less.

[0045] <Water-insoluble organic solvent (component C)> In one or more embodiments, the metal separating agent of the present disclosure comprises or contains a blend of component A, a thiocyanate (component B), and a water-insoluble organic solvent (component C).

[0046] In the present disclosure, the term "water-insoluble organic solvent" refers to an organic solvent that dissolves in an amount of 0.01 g or less in 100 g of water at 25°C. Examples of water-insoluble organic solvents (component C) include petroleum-based solvents such as kerosene; aliphatic hydrocarbon solvents such as hexane, isooctane, and dodecane; aromatic hydrocarbon solvents such as benzene, toluene, and xylene; halogenated solvents such as chloroform and dichloromethane; higher alcohol solvents such as dodecyl alcohol and octanol; and higher fatty acid solvents such as oleic acid. Among these, petroleum-based solvents such as kerosene are preferred from the viewpoint of recovery efficiency of the metals to be recovered. Component C may be one type or a combination of two or more types (mixed solvent). In the present disclosure, the phase derived from component C when the metal separating agent of the present disclosure is mixed with an aqueous solution may be referred to as the "organic phase."

[0047] When the metal separating agent of the present disclosure contains component C, the blending amount (mass%) of component C in the metal separating agent of the present disclosure is, from the viewpoint of the recovery efficiency of the target metal, preferably 50 mass% or more, more preferably 60 mass% or more, even more preferably 70 mass% or more, and preferably 99.9 mass% or less, more preferably 99 mass% or less, and even more preferably 95 mass% or less. More specifically, the blending amount (mass%) of component C in the metal separating agent of the present disclosure is preferably 50 mass% or more and 99.9 mass% or less, more preferably 60 mass% or more and 99 mass% or less, and even more preferably 70 mass% or more and 95 mass% or less. When component C is a combination of two or more types, the blending amount of component C refers to the total blending amount of the two or more types.

[0048] When the metal separating agent of the present disclosure contains component C, the mass ratio A / C of component A to component C in the metal separating agent of the present disclosure (amount of component A blended / amount of component C blended) is, from the viewpoint of the recovery efficiency of the desired metal, preferably 0.01 or more, more preferably 0.05 or more, and even more preferably 0.1 or more, and from the same viewpoint, is preferably 10 or less, more preferably 5.0 or less or 5 or less, and even more preferably 1.0 or less or 1 or less. More specifically, the mass ratio A / C (amount of component A blended / amount of component C blended) is preferably 0.01 or more and 10 or less, more preferably 0.05 or more and 5.0 or 0.05 or more and 5 or less, and even more preferably 0.1 or more and 1.0 or 0.1 or more and 1 or less.

[0049] When the metal separating agent of the present disclosure contains component C, the mass ratio B / C of components B to C in the metal separating agent of the present disclosure (compound amount of component B / compound amount of component C) is, from the viewpoint of the recovery efficiency of the desired metal, preferably 0.001 or more, more preferably 0.01 or more, and even more preferably 0.05 or more, and from the same viewpoint, is preferably 10 or less, more preferably 5 or less, and even more preferably 1 or less. More specifically, the mass ratio B / C (compound amount of component B / component C) is preferably 0.001 or more and 10 or less, more preferably 0.01 or more and 5 or less, and even more preferably 0.01 or more and 1 or less.

[0050] <Other ingredients> The metal separating agent of the present disclosure may contain other components as needed, as long as the effects of the present disclosure are not impaired. Examples of other components include an antifoaming agent and a demulsifier.

[0051] [Metal Separator Kit] In one aspect, the present disclosure relates to a metal separating agent kit for separating or separating and recovering a metal from an aqueous solution containing the metal, the metal separating agent kit including a first agent containing component A and a second agent containing component B (hereinafter also referred to as the "metal separating agent kit of the present disclosure"). In one or more embodiments, the first and second agents are mixed at the time of use. The first and second agents may each contain the above-mentioned optional components (component C, other components) as necessary. In one or more embodiments, an agent prepared by blending the metal separating agent kit of the present disclosure, that is, an agent obtained by mixing the first agent and the second agent, is the metal separating agent of the present disclosure. In one or more embodiments, the metal separating agent kit of the present disclosure is a kit for producing the metal separating agent of the present disclosure. In one or more embodiments, the metal separator kit of the present disclosure is a metal separator kit for separating or separating and recovering cobalt. In one or more embodiments, the metal separator kit of the present disclosure is a metal separator kit for separating or separating and recovering cobalt from an aqueous solution containing cobalt and nickel.

[0052] [Metal recovery method] In one aspect, the present disclosure relates to a metal recovery method for separating and recovering metals from a metal-containing aqueous solution, the metal recovery method including a step of contacting the metal-containing aqueous solution with a metal separating agent of the present disclosure or an agent containing the metal separating agent kit of the present disclosure to separate the metal from the aqueous phase into an organic phase (hereinafter also referred to as the "contacting step"), and a step of recovering the metal from the organic phase (hereinafter also referred to as the "recovery step") (hereinafter also referred to as the "metal recovery method of the present disclosure"). The metal recovery method of the present disclosure allows for efficient separation and recovery of the desired metal from the metal-containing aqueous solution (aqueous phase). In one or more embodiments, the metal recovery method of the present disclosure is excellent in cobalt recovery efficiency. Furthermore, in one or more embodiments, the metal recovery method of the present disclosure is excellent in Co-Ni separation ability. That is, in one or more embodiments, the metal recovery method of the present disclosure is a metal recovery method for separating and recovering cobalt from an aqueous solution containing cobalt. In one or more embodiments, the metal recovery method of the present disclosure is a metal recovery method for separating and recovering cobalt from an aqueous solution containing cobalt and nickel.

[0053] <Contact process> The contacting method and contacting conditions in the contacting step of the metal recovery method of the present disclosure can be the same as the contacting method and contacting conditions in the metal separation method of the present disclosure described above.

[0054] <Recovery process> In the recovery step, examples of a method for recovering the metal separated (distributed, extracted) in the organic phase include crystallization and electrolysis.

[0055] <Liquid separation process and back-extraction process> In one or more embodiments, the metal separation method and the metal recovery method of the present disclosure may further include the following liquid separation step (1) and back-extraction step (2). (1) A liquid separation step in which the aqueous phase and the organic phase contacted in the contact step are separated. (2) A back-extraction step in which the organic phase separated in the separation step is contacted with an aqueous phase other than the aqueous phase separated in the separation step to perform back-extraction. The aqueous solution other than the aqueous solution separated in the separation step (1) is not particularly limited as long as it can be used for back extraction, but is preferably an acidic aqueous solution or an aqueous solution containing a complexing agent such as ethylenediaminetetraacetic acid (EDTA) or thiourea. In the case of an acidic aqueous solution, its pH is preferably adjusted to be lower than the pH of the aqueous solution used in the contact step. The acid to be used is not particularly limited, but examples thereof include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, phosphorous acid, and hypophosphorous acid.

[0056] <Preparation process> In one or more embodiments, the metal separation method and the metal recovery method of the present disclosure may further include a step of preparing an aqueous solution containing a metal (hereinafter also referred to as a "preparation step"). The preparation method is not particularly limited, and the aqueous solution containing a metal may be obtained, or the aqueous solution containing a metal may be prepared by the user. The metal-containing aqueous solution is not particularly limited as long as it contains the metal to be separated and / or recovered, and is usually prepared under conditions that allow the metal to be separated and / or recovered to be separated (extracted) (if metals other than the metal to be separated and / or recovered are also contained, conditions that result in a difference between the extraction rate of the metal to be separated and / or recovered and the extraction rate of metals other than the metal to be separated and / or recovered), and it is preferable that the aqueous solution be prepared as an acidic aqueous solution. Examples of the metal-containing aqueous solution include those obtained by treating the above-mentioned electronic waste. When preparing an acidic aqueous solution containing a metal to be separated and / or recovered by oneself, the preparation method is not particularly limited, and an acid may be added to an aqueous solution containing the metal to be separated and / or recovered (to adjust the pH), or an acidic aqueous solution may be prepared to dissolve the metal to be separated and / or recovered. Examples of acids used to prepare the acidic aqueous solution include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, phosphorous acid, and hypophosphorous acid.

[0057] [Lithium-ion battery manufacturing method] In one aspect, the present disclosure relates to a method for manufacturing a lithium ion battery (hereinafter also referred to as the "lithium ion battery manufacturing method of the present disclosure"), which includes a step of contacting an aqueous solution containing a metal with an agent comprising the metal separator kit of the present disclosure to separate the metal from the aqueous phase to an organic phase (hereinafter also referred to as the "contact step"), a step of recovering the metal from the organic phase (hereinafter also referred to as the "recovery step"), and a step of manufacturing a battery using the metal recovered in the above step. The contacting method and contacting conditions in the contacting step of the lithium ion battery manufacturing method of the present disclosure can be the same as the contacting method and contacting conditions of the metal separation method of the present disclosure described above. The recovery method in the recovery step of the lithium ion battery manufacturing method of the present disclosure can be the same as the recovery method of the metal recovery method of the present disclosure described above. In one or more embodiments, the method for producing a lithium ion battery according to the present disclosure may further include the separation step (1) and the back-extraction step (2) described above. In one or more embodiments, the lithium-ion battery manufacturing method of the present disclosure may further include the above-mentioned preparation step. [Example]

[0058] The present disclosure will be specifically described below using examples, but the present disclosure is not limited to these examples in any way.

[0059] 1. Preparation of metal separation agent I (organic phase) A quaternary ammonium salt (component A shown in Table 1) and an organic solvent (component C shown in Table 1) were mixed at a mixing ratio of 0 to 30 vol%. Furthermore, ammonium thiocyanate (component B shown in Table 1) was added to the mixture at a ratio of 0.5 mol / L to prepare metal separating agent I (Examples 1 to 9, Comparative Examples 1 and 2). The blending amount (mass%) of each component in the metal separating agent of the present disclosure is shown in Table 1.

[0060] The following components were used as the metal separating agent. (Component A) <Production Example of Triester Methyl Ammonium Methyl Sulfate> Triester methylammonium methyl sulfate (compound name: methyl tris-[2-ethylhexyl ethyl]-ammonium methyl sulfate) [wherein R 1 , R 2 , R 3 is ethyl 2-ethylhexyl ester, and R 4 The compound in which X is methyl and X is methyl sulfate was obtained as follows. A four-neck flask equipped with a condenser was charged with 2-ethylhexyl acid, triethanolamine, hypophosphorous acid as a catalyst, and butylhydroxytoluene as an antioxidant. After purging with nitrogen, the mixture was heated to 170°C over 1.5 hours and stirred for 2 hours. The pressure was then reduced to 13.3 kPa over 1.5 hours, and the mixture was aged for 7 hours before being cooled to obtain an esteramine. The resulting esteramine was charged into a 2-L separable flask, purged with nitrogen, and heated to 65°C. Dimethyl sulfate was added dropwise over 1 hour, and the mixture was aged at 65°C for 4 hours. The mixture was then cooled to room temperature to obtain triestermethylammonium methylsulfate. <Production Example of Diester Methyl Ammonium Methyl Sulfate> Diester methylammonium methyl sulfate (compound name: (2-hydroxyethyl)-methylbis-[2-ethyl oleate]-ammonium methyl sulfate) [R in formula (I)] 1 , R 2 is ethyl oleate, and R 3 is hydroxyethyl, and R 4 The compound in which X is methyl and X is methyl sulfate was obtained as follows. A four-neck flask equipped with a condenser was charged with oleic acid, triethanolamine, hypophosphorous acid as a catalyst, and butylhydroxytoluene as an antioxidant. After purging with nitrogen, the mixture was heated to 170°C over 1.5 hours and stirred for 2 hours. The pressure was then reduced to 13.3 kPa over 1.5 hours, and the mixture was aged for 7 hours before being cooled to obtain an esteramine. The resulting esteramine was charged to a separable flask, purged with nitrogen, and heated to 65°C. Dimethyl sulfate was added dropwise over 1 hour, and the mixture was aged at 65°C for 4 hours. The mixture was then cooled to room temperature to obtain diestermethylammonium methylsulfate. <Production Example of Trietherhexylammonium Hydrochloride> Trietherhexylammonium hydrochloride (compound name: tris[2-hexoxyethyl]-hexyl-ammonium hydrochloride) [R in formula (I)] 1 , R 2 , R 3 is hexoxyethyl, and R 4The compound in which X is hexyl and X is chloride was obtained as follows. Triethanolamine, hexanol, and sodium hydroxide were charged into a four-neck flask, and after purging with nitrogen, the temperature was raised to 160°C. After heating, the pressure was reduced to 1.3 kPa or less and the mixture was stirred for 24 hours. The mixture was then cooled to room temperature, and water was added to terminate the reaction, yielding trietheramine. The resulting trietheramine was charged into a separable flask, and after purging with nitrogen, the mixture was heated to 65°C, while hexyl chloride was added dropwise over 1 hour, and the mixture was aged at 65°C for 4 hours. The mixture was then cooled to room temperature, yielding trietherhexylammonium hydrochloride. The synthetic raw materials used in the production of the above component A are shown below. <Synthetic raw materials> Triethanolamine [Tokyo Chemical Industry Co., Ltd.] 2-Ethylhexyl acid [Tokyo Chemical Industry Co., Ltd.] Oleic acid [Tokyo Chemical Industry Co., Ltd.] Hypophosphorous acid [Sigma-Aldrich] BHT [Tokyo Chemical Industry Co., Ltd.] Dimethyl sulfate [Tokyo Chemical Industry Co., Ltd.] Hexanol [Tokyo Chemical Industry Co., Ltd.] Sodium hydroxide [Tokyo Chemical Industry Co., Ltd.] Hexyl chloride [Tokyo Chemical Industry Co., Ltd.] <Trioctylmethylammonium methyl sulfate> A compound obtained by washing trioctylmethylammonium hydrochloride with an aqueous methylsulfate solution and converting it into methylsulfate. (Component B) Ammonium thiocyanate [Tokyo Chemical Industry Co., Ltd.] (Component C) Kerosene [Tokyo Chemical Industry Co., Ltd.]

[0061] 2. Preparation of aqueous solution II (aqueous phase, aqueous solution containing metals) Co sulfate and Ni sulfate were dissolved in 1 mol / L sulfuric acid to prepare aqueous solution II containing Co and Ni (Co concentration: 3.0 g / L, Ni concentration: 3.0 g / L). The pH of aqueous solution II is shown in Table 1. The content of each metal in aqueous solution II was 0.3 mass% for Co and 0.3 mass% for Ni.

[0062] [pH measurement method] The pH of Aqueous Solution II was measured at 25°C using a pH meter (HM-30G, manufactured by Toa Denpa Kogyo Co., Ltd.) one minute after the electrode was immersed in the polishing composition. The results are shown in Table 1.

[0063] 3. Evaluation of Metal Separating Agents (Examples 1 to 9, Comparative Examples 1 and 2) Metal separating agent I (organic phase) was contacted with aqueous solution II (aqueous phase), and the Co extraction ability and Co-Ni separation ability were evaluated. The specific procedures are as follows. [Metal extraction method] The metal separating agent I (organic phase) and the aqueous solution II (aqueous phase) were placed in a separatory funnel and contacted by shaking for 10 minutes at 20°C, and the metals were transferred (distributed) to the metal separating agent I (organic phase) to extract (separate) the metals. The volume ratio (aqueous phase volume / organic phase volume) of the contacted aqueous solution II (aqueous phase) to the metal separating agent I (organic phase) was 1.0. The amounts of each component in the metal separating agent I contacted with the aqueous solution II were 1500 mol% for component A, 2500 mol% for component B, and 25000 mol% for component C, relative to the Co concentration in the aqueous solution II. The Co and Ni concentrations in the metal separating agent I (organic phase) and aqueous solution II (aqueous phase) after extraction were quantitatively analyzed using ICP-OES, and the Co extraction rate and Co-Ni resolution were calculated. The results are shown in Table 1. The Co extraction rate and Co-Ni resolution are defined as follows: [Co extraction rate] The Co extraction rate was calculated by dividing the Co concentration (g / L) in the metal separating agent I after extraction by the initial (before extraction) Co concentration (g / L) in the aqueous solution I. Co extraction rate = (Co concentration in metal separating agent I after extraction) / (Co concentration in aqueous solution I before extraction) In addition, when the result is below the detection limit by ICP-OES, it is indicated as "below the detection limit" in Table 1. [Co-Ni separation ability] The Co-Ni separation ability is the ratio of the Co concentration (g / L) to the Ni concentration (g / L) in metal separating agent I after extraction, Co / Ni, divided by the ratio of the Co concentration (g / L) to the Ni concentration (g / L) in aqueous solution II after extraction, Co / Ni. Co-Ni separation ability = (Co / Ni concentration ratio in metal separating agent I after extraction) / (Co / Ni concentration ratio in aqueous solution II after extraction) In addition, for Examples 2 and 5, the Co—Ni separation ability was not calculated, and therefore is indicated in Table 1 as “-”.

[0064] [Table 1]

[0065] As shown in Table 1, in Examples 1 to 9, which used a quaternary ammonium salt represented by formula (I) (component A) and ammonium thiocyanate (component B), the Co extraction rate was 94% or higher. Furthermore, Examples 1 to 9 had better Co-Ni separation ability than Comparative Examples 1 and 2, which did not use component B. Furthermore, the Co-Ni separation ability of Examples 1, 3, and 4 was better than that of Example 9. Thus, it was confirmed that the metal separating agents of Examples 1 to 9 have high separation and recovery performance. In particular, in Example 1, which used triestermethylammonium methyl sulfate as component A, the Co extraction rate was 99% or higher and the separation ability was 1300 or higher, demonstrating higher separation and recovery performance. [Industrial Applicability]

[0066] The metal separating agent of the present disclosure can be used as a recovery agent for rare metals and precious metals.

Claims

1. A metal separation method for separating or separating and recovering cobalt from an aqueous solution containing cobalt, comprising: The method includes a step of contacting an aqueous solution containing cobalt with a metal separating agent containing a salt represented by the following formula (I) (component A), thiocyanic acid (component B), and a water-insoluble organic solvent (component C), and separating the cobalt from the aqueous phase into an organic phase, Component A is R in the following formula (I): 1 , R 2 and R 3 at least one of which is a compound having an ester group having 6 to 22 carbon atoms. 【Chemical 1】 In formula (I), R 1 is a hydrocarbon group having 6 to 22 carbon atoms which may have an ester group, an amide group, and / or an ether group, and R 2 and R 3 are each independently a hydrocarbon group having 6 to 22 carbon atoms which may have an ester group, an amide group and / or an ether group, or an alkyl group having 1 to 4 carbon atoms which may have a hydroxyl group, R 4 is an alkyl group having 1 to 6 carbon atoms or a hydrogen atom, and X - is an anion.

2. Component A is R in formula (I). 1 , R 2 and R 3 2. The metal separation method according to claim 1, wherein at least two of the compounds are compounds having an ester group having 6 to 22 carbon atoms.

3. Component A is R in formula (I). 1 , R 2 and R 3 2. The metal separation method according to claim 1, wherein the compound is a compound having an ester group having 6 to 22 carbon atoms.

4. 2. The metal separation method according to claim 1, wherein the mass ratio A / B of component A to component B in the metal separating agent is 0.01 or more and 50 or less.

5. 2. The metal separation method according to claim 1, wherein the content of component A in the metal separating agent is 1% by mass or more and 50% by mass or less.

6. 2. The metal separation method according to claim 1, wherein the content of component B in the metal separating agent is 0.5% by mass or more and 10% by mass or less.

7. 2. The method for separating metals according to claim 1, which is a method for separating or separating and recovering cobalt from an aqueous solution containing cobalt and nickel.

8. A metal separating agent kit for separating or separating and recovering cobalt from an aqueous solution containing cobalt, comprising: a first agent containing a salt (component A) represented by the following formula (I); and a second agent containing thiocyanic acid (component B): Component A is R in the following formula (I): 1 , R 2 and R 3 At least one of the above is a compound having an ester group having 6 to 22 carbon atoms. 【Chemistry 2】 In formula (I), R 1 is a hydrocarbon group having 6 to 22 carbon atoms which may have an ester group, an amide group, and / or an ether group, and R 2 and R 3 are each independently a hydrocarbon group having 6 to 22 carbon atoms which may have an ester group, an amide group and / or an ether group, or an alkyl group having 1 to 4 carbon atoms which may have a hydroxyl group, R 4 is an alkyl group having 1 to 6 carbon atoms or a hydrogen atom, and X - is an anion.

9. The metal separator kit according to claim 8, which is a metal separator kit for separating or separating and recovering cobalt from an aqueous solution containing cobalt and nickel.

10. A metal recovery method for separating and recovering cobalt from an aqueous solution containing cobalt, comprising: A metal recovery method comprising: a step of contacting an aqueous solution containing cobalt with an agent comprising the metal separating agent kit according to claim 8 to separate the cobalt from the aqueous phase into an organic phase; and a step of recovering the cobalt from the organic phase.

11. A method for manufacturing a lithium ion battery, comprising the steps of: contacting an aqueous solution containing cobalt with an agent comprising the metal separating agent kit described in claim 8 to separate the cobalt from the aqueous phase into an organic phase; recovering the cobalt from the organic phase; and manufacturing a battery using the cobalt recovered in the step.

12. A metal separating agent for separating or separating and recovering cobalt from an aqueous solution containing cobalt, comprising a salt (component A) represented by the following formula (I) and thiocyanic acid (component B): Component A is R in the following formula (I): 1 , R 2 and R 3 At least one of the above compounds has an ester group having 6 to 22 carbon atoms. 【Chemistry 3】 In formula (I), R 1 is a hydrocarbon group having 6 to 22 carbon atoms which may have an ester group, an amide group, and / or an ether group, and R 2 and R 3 are each independently a hydrocarbon group having 6 to 22 carbon atoms which may have an ester group, an amide group and / or an ether group, or an alkyl group having 1 to 4 carbon atoms which may have a hydroxyl group, R 4 is an alkyl group having 1 to 6 carbon atoms or a hydrogen atom, and X - is an anion.

13. A metal separating agent for separating or separating and recovering cobalt from an aqueous solution containing cobalt, comprising a salt (component A) represented by the following formula (I) and thiocyanic acid (component B): Component A is R in the following formula (I): 1 , R 2 and R 3 At least one of the above compounds has an ester group having 6 to 22 carbon atoms. 【Chemistry 4】 In formula (I), R 1 is a hydrocarbon group having 6 to 22 carbon atoms which may have an ester group, an amide group, and / or an ether group, and R 2 and R 3 are each independently a hydrocarbon group having 6 to 22 carbon atoms which may have an ester group, an amide group and / or an ether group, or an alkyl group having 1 to 4 carbon atoms which may have a hydroxyl group, R 4 is an alkyl group having 1 to 6 carbon atoms or a hydrogen atom, and X - is an anion.

14. The metal separating agent according to claim 12 or 13, wherein the mass ratio A / B of component A to component B is 0.01 or more and 50 or less.

15. The metal separating agent according to claim 12 or 13, which is obtained by blending component A, a thiocyanate (component B), and a water-insoluble organic solvent (component C).

16. The metal separating agent according to claim 12 or 13, wherein the content of component A is 1% by mass or more and 50% by mass or less.

17. The metal separating agent according to claim 12 or 13, wherein the content of component B is 0.5 mass% or more and 10 mass% or less.

18. The metal separating agent according to claim 12 or 13, which is a metal separating agent for separating or separating and recovering cobalt from an aqueous solution containing cobalt and nickel.

19. A metal separation method for separating cobalt from an aqueous solution containing cobalt, comprising: A method for separating metals, comprising the step of contacting an aqueous solution containing cobalt with the metal separating agent according to claim 12 or 13, and separating the cobalt from the aqueous phase into an organic phase.

20. A metal recovery method for separating and recovering cobalt from an aqueous solution containing cobalt, comprising: A step of contacting an aqueous solution containing cobalt with the metal separating agent according to claim 12 or 13, and separating the cobalt from the aqueous phase into an organic phase; and recovering cobalt from the organic phase.

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