Metal extracting agent and metal ion separation and recovery method using same

Abstract

Provided are a metal extraction agent for extracting metal ions present in an aqueous phase into an oil phase, and a method for separating and recovering metal ions, the method comprising mixing an oil phase containing the metal extraction agent for extracting metal ions present in the aqueous phase into the oil phase, and an aqueous phase containing a plurality of types of metal ions in the metal extraction agent, nitrogen atoms located at both ends of a molecular chain constituting the metal extractant do not constitute a carbamyl bond, and have an unsubstituted hydrocarbon group, and an unsubstituted hydrocarbon group or a coordination functional group selected from the following coordination functional group G1, which is a coordination functional group (alpha) for an extracted metal ion.

Description

Technical Field

[0001] The present invention relates to a metal extractant for extracting metal ions present in an aqueous phase into an oil phase and a method for separating and recovering metal ions using the metal extractant. Background Art

[0002] The amount of metals that can be mined from mines is limited, and the stable supply of precious metals, which are essential for precision equipment, has become an important issue. Therefore, it is important to recover valuable metals from industrial waste without relying on mining.

[0003] In particular, with the popularity of electric vehicles in recent years, the amount of discarded lithium-ion batteries (LiB) has increased year by year. LiB uses positive electrode active materials containing metal elements such as cobalt and nickel, and the demand for nickel is expected to increase significantly. In order to cope with the increase in demand for valuable metals accompanying this trend, it is expected that not only the amount of mining will be increased, but also the technology for recovering metals from waste LiB will be expected.

[0004] As a method for recovering metals from waste, a wet extraction method (solvent extraction method) is used. In the wet extraction method, if an organic phase containing a metal extractant is brought into contact with an aqueous solution (aqueous phase) containing ions of metal elements (referred to as metal ions) and mixed and left to stand, the two phases are separated, so that the ions of the metal coordinated with the metal extractant can be moved (extracted) into the organic phase. The organic phase is taken out, the metal ions are reversely extracted, and purified as needed, so that it can be recovered as a (high-purity) metal.

[0005] For example, Patent Document 1 describes a method for recovering metal ions by using a "polyamine compound represented by formula (1)" as a chelating agent (metal extractant). Specifically, the following is described: As shown in the following formula (1), a polyamine compound having an ethylenediamine skeleton with terminal nitrogen atoms substituted with carboxymethyl and substituted carbamoylmethyl groups can be used to extract copper ions in an aqueous phase into an oil phase. In addition, Patent Document 2 describes a "method for removing impurities from an acid leaching solution of a nickel oxide ore containing valuable components such as nickel, cobalt, and scandium, and separating valuable components and impurities" and a specific "valuable metal extractant composed of an amide derivative represented by formula (I)" used in the method. Specifically, the valuable metal extractant is an amide derivative in which one amide group is introduced into an amino acid such as glycine as shown in the following formula (I).

[0006] [Chemical formula 1]

[0007]

[0008] Previous technical literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application Publication No. 2016-028021

[0011] Patent Document 2: Japanese Patent Application Publication No. 2014-205900 Summary of the invention

[0012] Technical issues to be solved by the invention

[0013] Patent Documents 1 and 2 state that specific metal ions present in the aqueous phase can be extracted and recovered in the oil phase when the metal extractants described in Patent Documents 1 and 2 are used. However, the selectivity or recovery rate of the extracted metal ions is insufficient in any metal extractant, and there is room for improvement.

[0014] Moreover, in patent documentation 1 and 2, do not study in the aqueous phase coexisting multiple metal ions extracting ions of more than two kinds of metal elements belonging to different families in the periodic table as ions of valuable metal elements, highly selectively and reclaim one kind of metal ion therein with high recovery rate (highly selectively and highly recovering ions of more than two kinds of metal elements belonging to different families). This is because the demand for separation and recovery of metal ions belonging to the 9th family and the 10th family, such as cobalt ions and nickel ions, has increased sharply due to the rapid popularization of lithium ion batteries in recent years, and it is not easy to separate and recycle metal ions similar to physical behavior and chemical behavior in the past. However, as ions of more than two kinds of valuable metal elements belonging to different families, if it is possible to extract metal ions (especially cobalt ions) belonging to the 9th family and metal ions (especially nickel ions) belonging to the 10th family whose physical behavior and chemical behavior are similar, and highly selectively and reclaim one kind of metal ion therein with high recovery rate, it is possible to make a great contribution to the further popularization of electric vehicles and the creation of a sustainable society.

[0015] An object of the present invention is to provide a metal extractant capable of extracting specific metal ions from a plurality of metal ions present in an aqueous phase into an oil phase with high selectivity and high recovery rate, and a method for separating and recovering metal ions using the metal extractant.

[0016] Furthermore, in a preferred embodiment of the present invention, the object is to provide a metal extractant and a method for separating and recovering metal ions using the metal extractant, wherein the metal extractant can extract ions of two or more metal elements belonging to different groups in the periodic table from a plurality of metal ions present in an aqueous phase, and can extract one of the metal ions into an oil phase with high selectivity and high recovery rate.

[0017] Means for solving technical problems

[0018] The present inventors have found that by using a metal extractant for a wet extraction method for separating and recovering metal ions from an aqueous phase containing a plurality of metal ions as a compound having the following chemical structure, a specific metal ion can be extracted from the aqueous phase into an oil phase with high selectivity and high recovery rate, and can be separated and recovered from other metal ions present in the aqueous phase: the metal extractant has a molecular chain having nitrogen atoms at both ends in the molecular structure, and an unsubstituted hydrocarbon group and a group containing a specific coordination functional group for the extracted metal ion or two unsubstituted hydrocarbon groups are introduced without forming a carbamoyl bond on the nitrogen atoms at both ends of the molecular chain. In addition, it has been found that by using the compound having the above chemical structure as a metal extractant in a wet extraction method, ions of two or more metal elements belonging to different groups, particularly preferably cobalt ions and nickel ions, can be extracted from the plurality of metal ions present in the aqueous phase, and one of the metal ions can be extracted into the oil phase with high selectivity and high recovery rate.

[0019] The present inventors have further conducted research based on these findings and have finally completed the present invention.

[0020] That is, the above-mentioned problems are solved by the following scheme.

[0021] <1> A metal extractant, which extracts metal ions present in an aqueous phase into an oil phase, wherein:

[0022] In the metal extractant, the nitrogen atoms at both ends of the molecular chain constituting the metal extractant do not form a carbamoyl bond, and have an unsubstituted hydrocarbon group, and the coordinating functional group (α) for the extracted metal ion includes any coordinating functional group group G1 described below or an unsubstituted hydrocarbon group.

[0023] <Coordinating functional group G1>

[0024] Hydroxyl group, ether group, thiol group, thioether group, nitrile group, isonitrile group, carboxyl group, amino group, amide group, phosphoric acid group, phosphonic acid group, sulfonic acid group, sulfinic acid group, phosphine group, nitrogen-containing heterocycle, oxygen-containing heterocycle, sulfur-containing heterocycle.

[0025] <2> according to <1> The metal extractant, wherein

[0026] The group including the coordinating functional group is a hydrocarbon group having a coordinating functional group.

[0027] <3> according to <1> or <2> The metal extractant, wherein

[0028] At least one of the coordinating functional groups is selected from a carboxyl group, a phosphoric acid group, a phosphonic acid group, a sulfonic acid group and a sulfinic acid group.

[0029] <4> according to <1> to <3> The metal extractant described in any one of the preceding claims is used for extracting and separating metal ions of two or more elements belonging to different groups in the periodic table among the metal ions.

[0030] <5> according to <1> to <4> The metal extractant according to any one of the preceding claims, wherein

[0031] The metal extractant is represented by the following formula (I).

[0032] [Chemical formula 2]

[0033] Formula (I)

[0034]

[0035] In formula (I), R 1 represents an unsubstituted hydrocarbon group.

[0036] R 2 represents a substituent, wherein L 3 The R of the bonded N 2 represents an unsubstituted hydrocarbon group,

[0037] X each independently represents a group selected from the following coordination functional group group G2,

[0038] L 1 , L 2 and L 3 Each independently represents a linking group.

[0039] n is an integer of 1-5.

[0040] <Coordinating functional group G2>

[0041] Carboxyl group, phosphoric acid group, phosphonic acid group, sulfonic acid group, sulfinic acid group, hydroxyl group.

[0042] <6> according to <5> The metal extractant, wherein

[0043] X is a carboxyl group, a phosphoric acid group, a phosphonic acid group, a sulfonic acid group or a sulfinic acid group.

[0044] <7> according to <1> The metal extractant, wherein

[0045] The metal extractant is represented by the following formula (II).

[0046] [Chemical formula 3]

[0047]

[0048] In formula (II), R 3 ~R 5 Each independently represents an unsubstituted hydrocarbon group,

[0049] R 6 represents a substituent, wherein 5 The R of the bonded N 6 represents an unsubstituted hydrocarbon group.

[0050] L 4 Represents a linker.

[0051] m is an integer of 1-5.

[0052] <8> A method for separating and recovering metal ions, comprising mixing an aqueous phase containing a plurality of metal ions and an oil phase containing the metal extractant according to any one of claims 1 to 7.

[0053] <9> according to <8> The separation and recovery method, wherein:

[0054] The oil layer contains <7> In the case of the metal extractant, the aqueous phase contains halide ions.

[0055] <10> according to <8> or <9> The separation and recovery method, wherein:

[0056] Among the plurality of metal ions, two or more metal ions belonging to different groups of the periodic table are extracted from the aqueous phase and recovered into the oil phase.

[0057] <11> according to <10> The separation and recovery method, wherein:

[0058] Metal ions of two or more elements are metal recyclables from waste batteries.

[0059] Effects of the Invention

[0060] The present invention can provide a metal extractant capable of extracting specific metal ions from a plurality of metal ions present in an aqueous phase into an oil phase with high selectivity and high recovery rate, and a method for separating and recovering metal ions using the metal extractant.

[0061] Furthermore, in a preferred embodiment of the present invention, a metal extractant and a method for separating and recovering metal ions using the metal extractant can be provided, wherein the metal extractant can extract ions of two or more metal elements belonging to different groups (particularly preferably cobalt ions and nickel ions) from a plurality of metal ions present in an aqueous phase, and can extract one of the metal ions into an oil phase with high selectivity and high recovery rate.

[0062] The above-mentioned features and other features and advantages of the present invention will become more apparent from the following description with appropriate reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1is the metal extractant E-1 synthesized in the embodiment 1 H-NMR spectrum.

[0064] Figure 2 This is the FT-IR chart of the metal extractant E-1 synthesized in the example.

[0065] Figure 3 The metal extractant E-3 synthesized in the embodiment 1 H-NMR spectrum. DETAILED DESCRIPTION

[0066] In the present invention, when the content, physical properties, etc. of a component are described by showing a numerical range, when the upper limit and lower limit of the numerical range are described respectively, any upper limit and lower limit can be appropriately combined to be set to a specific numerical range. On the other hand, when a plurality of numerical ranges represented by " to " are set and described, the upper limit and lower limit forming the numerical range are not limited to the specific combination recorded before and after the " to " as a specific numerical range, and can be set to the numerical range formed by appropriately combining the upper limit and lower limit of each numerical range. In addition, the numerical range represented by " to " in the present invention refers to the range including the numerical values ​​recorded before and after the " to " as the lower limit and the upper limit.

[0067] In the present invention, the term "compound" (for example, when the term "compound" is appended to the end) refers to the compound itself and includes salts and ions thereof, and also includes derivatives modified by introducing substituents, etc., within the scope of not impairing the effects of the present invention.

[0068] In the present invention, regarding the substituent, linking group, etc. (hereinafter referred to as substituent, etc.) that is not clearly described as substituted or unsubstituted, it means that the group may have an appropriate substituent. Therefore, in the present invention, even in the case of simply being described as a YYY group, the YYY group includes a mode with a substituent in addition to a mode without a substituent. This is also applicable to compounds that are not indicated as substituted or unsubstituted. As a preferred substituent, for example, a group selected from the substituent Z described later can be cited.

[0069] In the present invention, when there are multiple substituents represented by specific symbols or when multiple substituents are defined simultaneously or selected, it means that each substituent may be the same or different from each other. Furthermore, even if there is no special explanation, when multiple substituents are adjacent, it means that these may be connected or fused to each other to form a ring.

[0070] In addition, in this specification, "metal elements belonging to different groups in the periodic table" are sometimes referred to as "heterogroup metal elements", and in particular, "heterogroup metal elements in the same period in the periodic table" are referred to as "heterogroup metal elements in the same period". In addition, "ions of heterogroup metal elements" and "ions of heterogroup metal elements in the same period" are sometimes referred to as "heterogroup metal ions" and "heterogroup metal ions in the same period", respectively.

[0071] In the present invention, "ppm" indicating content and the like is based on mass and means "mass ppm" unless otherwise specified.

[0072] [Metal Extractants]

[0073] The metal extractant of the present invention is a compound that shows the function of extracting metal ions present in the aqueous phase into the oil phase, and can be preferably used in a wet extraction method in particular. If the metal extractant of the present invention is used in a wet extraction method, specific metal ions can be extracted into the oil phase from a variety of metal ions present in the aqueous phase with high selectivity and high recovery. In addition, in a preferred embodiment of the present invention, among the various metal ions present in the aqueous phase, more than two kinds of heterogeneous metal ions can be extracted, for example, more than two kinds of metal ions belonging to the 4th, 7th, 9th and 10th families, and cobalt ions and nickel ions as heterogeneous metal ions of the same period are particularly preferred as ions of the valuable metal element, and one of the metal ions can be extracted into the oil phase with high selectivity and high recovery.

[0074] In the present invention, being able to extract metal ions with high selectivity means that, in the metal ions extracted more than 2 kinds, the ratio [(the extraction amount of the specific metal ion) / (the total extraction amount of other metal ions)] of the extraction amount of the specific metal ion (usually 1 kind) as the extraction target relative to the total extraction amount of other metal ions can be extracted and separated from other metal ions with a ratio (resolution, selectivity) of more than 3.0. The above ratio is preferably more than 3.5, more preferably more than 5.0, and further preferably more than 9.0. As the upper limit, it is not particularly limited, and when extracting 2 kinds of metal ions, for example, it can be set to 20.

[0075] And, in the present invention, being able to extract metal ions with high recovery rate means that, about the metal ion (specific metal ion as extraction target) extracted with maximum extraction amount among the two or more metal ions extracted, as the ratio [(extraction amount in the oil phase of metal ions) / (content of the metal ions in the water phase)] of the extraction amount in the oil phase of the metal ion relative to the content of the metal ion in the water phase (before extraction), it is possible to extract with a ratio of more than 0.6. The above ratio is preferably more than 0.8, more preferably more than 0.9. As the upper limit, there is no particular limitation, it is desirable to be present in the total amount of the metal ions in the water phase, for example, preferably below 0.99, and can also be set to below 0.95 or below 0.90. As a specific extraction amount, it can be set to below 30,000 mass ppm, preferably below 20,000 mass ppm.

[0076] The detailed reasons why the metal extractant of the present invention exhibits the above-mentioned effects are not yet clear, but are considered to be as follows. That is, it is believed that the nitrogen atoms at both ends of the molecular chain of the metal extractant of the present invention do not form a carbamoyl bond, so that the structural isomerization of the complex ion formed by coordination with the metal ion can be suppressed, thereby achieving high selectivity. In addition, it is believed that the dissolution stability of the metal extractant in the oil phase is improved by having an unsubstituted hydrocarbon group at the end nitrogen atom, and the extraction behavior of the metal ion into the oil phase remains constant, thereby achieving a high recovery rate.

[0077] The metal extractant of the present invention is a compound having a molecular structure represented by the following structure A.

[0078] Structure A: The molecular structure of the metal extractant contains a molecular chain with nitrogen atoms at both ends.

[0079] The nitrogen atoms located at both ends of the molecular chain (sometimes referred to as terminal nitrogen atoms) do not constitute a carbamoyl bond and have an unsubstituted hydrocarbon group, and the coordinating functional group (α) for the extracted metal ion includes any coordinating functional group group G1 described below or an unsubstituted hydrocarbon group.

[0080] <Coordinating functional group G1>

[0081] Hydroxyl group, ether group, thiol group, thioether group, nitrile group, isonitrile group, carboxyl group, amino group, amide group, phosphoric acid group, phosphonic acid group, sulfonic acid group, sulfinic acid group, phosphine group, nitrogen-containing heterocycle, oxygen-containing heterocycle, sulfur-containing heterocycle.

[0082] One preferred embodiment of the metal extractant of the present invention is a compound having a molecular structure represented by the following structure B, in addition to the structure A.

[0083] Structure B: having two or more functional groups selected from the group of coordinating functional groups G1 as coordinating functional groups (α) for the extracted metal ions.

[0084] In the present invention, regarding the structure A, the metal extractant having one unsubstituted hydrocarbon group and one group containing a coordinating functional group (α) at ​​two terminal nitrogen atoms is referred to as "metal extractant I", and the metal extractant having two unsubstituted hydrocarbon groups at two terminal nitrogen atoms is referred to as "metal extractant II". Furthermore, in the present invention, the term "metal extractant" refers to a general term including metal extractants I and II unless otherwise specified.

[0085] The molecular chain having nitrogen atoms at both ends in structure A may be a straight chain, a branched chain, or a cyclic chain, preferably a straight chain or a branched chain, and may contain a cyclic chain (cyclic structure) such as a cycloalkylene group or an arylene group in part of the straight chain or the branched chain. The molecular chain is preferably a straight chain without a cyclic chain.

[0086] Here, the molecular chain refers to an atomic chain formed by a plurality of atoms bonded in a chain, and the longest chain with nitrogen atoms at both ends. That is, the molecular chain refers to a chain obtained by removing the groups bonded to the terminal nitrogen atoms from the chemical structure of the metal extractant (excluding the substituents bonded to the chain). For example, the molecular chain of the metal extractant E-1 in the example is N—CH 2 -CH 2 -N(ethylenediamine molecular chain), metal extractant T-1 becomes N-CO-CH 2 -N-CH 2 -CH 2 -N-CH 2 -C0-N (triethylenetetramine molecular chain).

[0087] The molecular chain is not particularly limited, and examples thereof include a connecting chain L having terminal nitrogen atoms bonded to each other. N As the connecting chain L N , is not particularly limited, and examples thereof include alkylene groups (preferably having 1 to 12 carbon atoms, more preferably 1 to 6, and further preferably 1 to 4), alkenylene groups (preferably having 2 to 6 carbon atoms, more preferably 2 to 3), arylene groups (preferably having 6 to 24 carbon atoms, more preferably 6 to 10), oxygen atoms, sulfur atoms, imino groups (-NR N -:R N represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms. ), a carbonyl group, a phosphate linking group (-OP(OH)(O)-O-), a phosphonic acid linking group (-P(OH)(O)-O-), or a group involved in a combination thereof. As a linking chain L N, preferably an alkylene group, an arylene group, a carbonyl group, an oxygen atom, a sulfur atom or an imino group, or a group involved in a combination thereof, more preferably an alkylene group, an arylene group or an imino group, or a group involved in a combination thereof. Here, the alkylene group and the alkenylene group can be any one of a straight chain, a branched chain, and a cyclic chain, preferably a straight chain or a branched chain, and a cyclic chain (cyclic structure) can also be included in a part of the straight chain or the branched chain. The alkylene group and the alkenylene group are preferably straight chains that do not contain cyclic chains, and are preferably straight chains in which the terminal nitrogen atoms are bonded to both ends of the longest carbon chain. As a connecting chain L N , preferably does not have a hetero atom such as an oxygen atom, a sulfur atom, or a nitrogen atom (imino group) at its terminal, and more preferably the atoms at both terminals are carbon atoms.

[0088] In the group related to the combination, the number of the combined groups, linking groups or atoms is not particularly limited, and can be, for example, 2 to 15, preferably 2 to 10, and more preferably 2 to 5. In addition, the number of types of the combined groups, linking groups or atoms is not particularly limited, and can be, for example, 2 or more, and preferably 2 or 3.

[0089] Among them, a linking group including a hydrocarbon group, an imino group, etc. is preferred, a hydrocarbon group or a group composed of a hydrocarbon group and an imino group is more preferred, and a hydrocarbon group is further preferred. Here, as the hydrocarbon group, the above-mentioned alkylene group, the above-mentioned alkenylene group, the above-mentioned arylene group, etc. can be cited, and an alkylene group is preferred, and an ethylene group is more preferred. The group composed of a hydrocarbon group and an imino group can be cited as a group composed of hydrocarbon groups and imino groups alternately bonded (polyamine skeleton), for example, -[hydrocarbon group-(imino group-hydrocarbon group) NN NN is not particularly limited and is an integer of 0 to 4, preferably an integer of 0 to 3, and more preferably 0 or 1.

[0090] The above connecting chain L N The number of connecting atoms is preferably 15 or less, more preferably 13 or less, further preferably 10 or less, and particularly preferably 6 or less. The lower limit is 1 or more. The above-mentioned number of connecting atoms refers to the minimum number of atoms between the connecting end nitrogen atoms. N The number of atoms not possessed by the imino group is N As an example, it can be set to 1 to 100, preferably 1 to 40, more preferably 1 to 24, and even more preferably 1 to 12.

[0091] For example, in the molecular chain N-CH 2 -CH 2 -N, forming a connection chain L N The number of atoms is 8, but the number of connecting atoms is 4.

[0092] In the molecular chain, from the viewpoint of metal ion selectivity and recovery rate, the two terminal nitrogen atoms do not form a carbamoyl bond (also called an amide bond, composed of -CO-NR N - indicates a bond. N As described above. ). In the present invention, the terminal nitrogen atom does not constitute a carbamoyl group means that, when a carbon atom is directly bonded to the terminal nitrogen atom, the carbon atom does not have a ketooxy group (=O) as a substituent, and preferably means that the carbon atom directly bonded to the terminal nitrogen atom has only a hydrogen atom, that is, a methylene group.

[0093] Furthermore, in the metal extractant, regarding the group containing the coordinating functional group (α) bonded to the terminal nitrogen atom, it is also preferred that the terminal nitrogen atom does not form a carbamoyl bond. In addition, other nitrogen atoms (nitrogen atoms forming amino groups or imino groups) present in the molecular structure other than the terminal nitrogen atom may form a carbamoyl group (-CO-N(R N ) 2 ) or carbamoyl bonds, but from the viewpoint of metal ion selectivity and recovery rate, it is particularly preferred that all nitrogen atoms do not constitute a carbamoyl group (-CO-N(R N ) 2 ) and carbamoyl bonds.

[0094] The unsubstituted hydrocarbon group possessed by the terminal nitrogen atom is not particularly limited as long as it is a hydrocarbon group without a substituent, and examples thereof include unsubstituted alkyl groups, unsubstituted alkenyl groups, unsubstituted aryl groups, unsubstituted aralkyl groups, or combinations thereof, preferably unsubstituted alkyl groups, unsubstituted aryl groups, and more preferably unsubstituted alkyl groups. The group composed of a combination is not particularly limited, and examples thereof include a group composed of an unsubstituted alkyl group or an unsubstituted aralkyl group and an unsubstituted aryl group. The unsubstituted hydrocarbon group does not have a coordination functional group included in the coordination functional group group G1 described later.

[0095] The alkyl group constituting the unsubstituted alkyl group, the unsubstituted alkenyl group and the unsubstituted aralkyl group may be linear, branched or cyclic, and is preferably linear or branched, and more preferably branched.

[0096] The number of carbon atoms of the unsubstituted alkyl group and the unsubstituted alkenyl group is not particularly limited, and can be, for example, 1 to 36. From the viewpoint of solubility in the oil phase, the number of carbon atoms is preferably 4 to 30, more preferably 4 to 24, and more preferably 6 to 20. The number of carbon atoms of the unsubstituted aryl group is not particularly limited, and can be, for example, 6 to 24, and preferably 6 to 10. The number of carbon atoms of the unsubstituted aralkyl group is not particularly limited, and can be, for example, 7 to 25, and preferably 7 to 11.

[0097] The group containing a coordinating functional group may be any group having one or more of any coordinating functional groups in the coordinating functional group group G1 described later, including a group consisting of a coordinating functional group and a group consisting of a coordinating functional group and a bonding group bonding the coordinating functional group to a terminal nitrogen atom.

[0098] The coordinating functional group will be described later. There is no particular limitation on the bonding group, and its meaning is the same as that of L in the formula (I) described later. 2 has the same meaning as , and preferably includes a hydrocarbon group having a coordinating functional group (an alkyl group, an alkenyl group or an aryl group or a group formed by combining these) as described later.

[0099] As the group containing a coordinating functional group, a group consisting of a coordinating functional group and a bonding group that bonds the coordinating functional group to the terminal nitrogen atom is preferred, and more preferably a group having the same meaning as “XL” in the formula (I) described later. 2 -" groups have the same meaning.

[0100] In the metal extractant I, the combination of unsubstituted alkyl groups possessed by the terminal nitrogen atoms and the combination of groups containing a coordinating functional group may be the same or different, but any combination is preferably the same.

[0101] In the metal extractant II, the four unsubstituted alkyl groups possessed by the terminal nitrogen atoms may be the same or different. Preferably, one unsubstituted alkyl group possessed by each terminal nitrogen atom is the same as each other, and preferably, the four unsubstituted alkyl groups are the same.

[0102] A preferred embodiment of the metal extractant of the present invention is as follows: in its molecular structure, as a coordination functional group (α) that coordinates and bonds with the metal ion to be extracted, it contains two or more arbitrary coordination functional groups (also simply referred to as functional groups) included in the following coordination functional group group G1 (Structure B).

[0103] The number of types of the coordination functional groups possessed by the metal extractant is not particularly limited, and may be one or more than two, but is preferably 1 to 5, and more preferably 1 or 2. In addition, as described later, the total number of the coordination functional groups possessed by the metal extractant is equivalent to the imino group of the terminal nitrogen atom as the coordination functional group, so it is at least 2, but in the case of having a coordination functional group other than the terminal nitrogen atom, as long as it is 3 or more, there is no particular limitation and it can be appropriately set. For example, in the metal extractant I, it is preferably 4 or more, more preferably 4 to 10, further preferably 4 to 8, and particularly preferably 4 to 6. On the other hand, in the metal extractant II, it is only necessary to be 2 or more, more preferably 2 to 8, further preferably 2 to 6, and particularly preferably 2 to 4. In the metal extractant, the number of imino groups contained in the molecular chain in the coordination functional group is 2 or more, but it is appropriately determined in consideration of the total number of the above-mentioned coordination functional groups, for example, it is preferably 2 to 6, preferably 2 or 3.

[0104] <Coordinating functional group G1>

[0105] Hydroxyl (-OH), ether (-O-), thiol (-SH: also known as mercapto, sulfanyl), sulfide (-S-), nitrile (-CN), isonitrile (-NC), carboxyl (-COOH), amino (-N(R N ) 2 ), amide (-CO-N (R N ) 2 : Also known as carbamoyl. ), phosphate group (-OPO 3 H 2 ), phosphonic acid group (-PO 3 H 2 ), sulfonic acid (-SO 3 H), sulfinic acid (-SO 2 H), phosphino (-PH 2 ), nitrogen-containing heterocycles, oxygen-containing heterocycles, sulfur-containing heterocycles

[0106] Here, R N As mentioned above.

[0107] In addition, the phosphoric acid group, the phosphonic acid group, the sulfonic acid group, and the sulfinic acid group all include groups in which at least one oxygen atom is substituted with a nitrogen atom or a sulfur atom.

[0108] Among the above-mentioned coordination functional groups, amino, amide, phosphoric acid, phosphonic acid, sulfonic acid, sulfinic acid, phosphino, nitrogen-containing heterocyclic ring, oxygen-containing heterocyclic ring, sulfur-containing heterocyclic ring, etc. can be present as substituents at the ends of the molecular structure, or can be present in the molecular structure as a connecting group (bond) in the above-mentioned molecular chain or bonding group. In this case, the hydrogen atoms or substituents of each group or ring are removed and introduced into the molecular structure. For example, if it is an amino group (-N(R N ) 2 ), then as the imino group (-NR N -) is introduced into the molecular structure. In the present invention, the amino group introduced into the molecular structure as an imino group is equivalent to a coordination functional group and is included in the number of coordination functional groups possessed by the metal extractant. Similarly, the terminal nitrogen atom of the molecular chain is equivalent to the amino group as a coordination functional group introduced as an imino group, and the number of the two terminal nitrogen atoms possessed by the molecular chain is included in the number of coordination functional groups possessed by the metal extractant.

[0109] When the ether group or thioether group is present at the end of the molecular chain, it has a substituent. The substituent constituting the ether group or thioether group is not particularly limited, and examples thereof include groups selected from the substituent Z described below, and preferably include alkyl groups, aryl groups, heteroatom-containing ring groups, and the like.

[0110] When an amino group is introduced as a substituent, a carbamoyl group (—CO—N(R N ) 2 ), but preferably does not form a carbamoyl group (the carbon atom directly bonded to the nitrogen atom does not have a ketooxy group as a substituent). On the other hand, when an amino group is introduced as an imino group in the molecular chain, the imino group corresponding to the terminal nitrogen atom does not form a carbamoyl bond (-CO-NR N -), other imino groups (sometimes referred to as internal nitrogen atoms) may or may not form carbamoyl bonds (-CO-NR N The internal nitrogen atom preferably does not form a carbamoyl bond (-CO-NR N -).

[0111] The nitrogen-containing heterocycle, oxygen-containing heterocycle, and sulfur-containing heterocycle are heterocycles having carbon atoms and at least one nitrogen atom, oxygen atom, or sulfur atom as ring-constituting atoms, respectively. The number of carbon atoms constituting each heterocycle is not particularly limited, and is preferably 2 to 20, for example. Each heterocycle includes an aromatic heterocycle and an aliphatic heteroatom-containing ring group, and is preferably a 5-membered ring or a 6-membered ring. For example, the heterocycle of the substituent Z described later can be cited.

[0112] Acidic groups such as carboxyl, phosphoric acid, phosphonic acid, sulfonic acid, sulfinic acid, phosphino, amino, amide, nitrogen-containing heterocycle, etc. can form salts. There are no particular restrictions on the cations that form the salts, and examples thereof include metal cations, especially metal cations of the first or second family, organic cations, etc. There are no particular restrictions on the organic cations, and examples thereof include ammonium cations, alkylammonium cations, etc.

[0113] As the coordination functional group possessed by the metal extractant, among the functional groups belonging to the above-mentioned coordination functional group group G1, amino group, carboxyl group, phosphoric acid group, phosphonic acid group, sulfonic acid group, sulfinic acid group, phosphino group, hydroxyl group, and ether group are preferred. As the coordination functional group other than the amino group introduced into the molecular chain as an imino group, carboxyl group, phosphoric acid group, phosphonic acid group, sulfonic acid group, sulfinic acid group, hydroxyl group, and ether group are more preferred, carboxyl group, phosphoric acid group, phosphonic acid group, sulfonic acid group, and sulfinic acid group are further preferred, and carboxyl group is particularly preferred.

[0114] In the case where the metal extractant has a plurality of coordination functional groups, the combination of coordination functional groups is not particularly limited, and the coordination functional groups contained in the coordination functional group group G1 can be appropriately combined with each other. For example, the metal extractant, wherein, in particular, the metal extractant I has an amino group (as an imino group (terminal nitrogen atom)) as a coordination functional group, and therefore preferably has an amino group that becomes a terminal nitrogen atom as a coordination functional group, and as at least one coordination functional group other than it, has a functional group selected from carboxyl, phosphoric acid, phosphonic acid, sulfonic acid, sulfinic acid and hydroxyl, preferably has an amino group and at least one functional group selected from carboxyl, phosphoric acid, phosphonic acid, sulfonic acid, sulfinic acid and ether, and more preferably has an amino group and a carboxyl group. On the other hand, the metal extractant II may have a coordination functional group other than the amino group that becomes the above-mentioned terminal nitrogen atom, but preferably does not have it.

[0115] The metal extractant is preferably a compound in which the above-mentioned unsubstituted hydrocarbon group or the like is introduced into the terminal nitrogen atom of the mono- or poly-(alkylene diamine) corresponding to the above-mentioned molecular chain, and more preferably a compound in which the above-mentioned unsubstituted hydrocarbon group or the like is introduced into the terminal nitrogen atom of the mono- or poly-(ethylene diamine). As the mono-(or poly) (alkylene diamine), for example, alkylene diamine, dialkylene triamine, trialkylene tetramine, tetraalkylene pentamine, pentaalkylene hexamine, etc. are preferably mentioned. Here, the meaning of the alkylene group constituting the mono-(or poly) (alkylene diamine) is the same as that constituting the above-mentioned connecting chain L. N The alkylene group has the same meaning as the alkylene group.

[0116] The metal extractant may have a substituent other than the coordinating functional group included in the coordinating functional group group G1. Examples of the substituent that may be possessed include a group selected from the substituent Z described below.

[0117] The metal extractant may have the above-mentioned structures A and B, but preferably has no carbamoyl group or carbamoyl bond from the viewpoint of the selectivity and recovery rate of metal ions.

[0118] The molecular weight of the metal extractant is not particularly limited, and can be, for example, 150 to 50,000, preferably 200 to 10,000, and more preferably 250 to 1,000 from the viewpoint of solubility in the oil phase. In the present invention, when the metal extractant is an oligomer, the molecular weight thereof refers to the number average molecular weight calculated based on standard polyfluoride by gel permeation chromatography (GPC) unless otherwise specified.

[0119] -Measurement of Molecular Weight-

[0120] The molecular weight of the oligomer is basically determined by the method of the following condition 1 or condition 2 (preferably): however, an appropriate eluent may be appropriately selected and used depending on the type of the oligomer.

[0121] (Condition 1)

[0122] Column: Two TOSOH TSKgel Super AWM-H (trade name, manufactured by Tosoh Corporation) connected

[0123] Carrier: 10mMLiBr / N-methylpyrrolidone

[0124] Measurement temperature: 40℃

[0125] Carrier flow rate: 1.0ml / min

[0126] Sample concentration: 0.1 mass%

[0127] Detector: RI (refractive index) detector

[0128] (Condition 2)

[0129] Column: A column obtained by connecting TOSOH TSKgel Super HZM-H, TOSOH TSKgel Super HZ4000, and TOSOH TSKgel Super HZ2000 (all trade names, manufactured by Tosoh Corporation) was used.

[0130] Carrier: Tetrahydrofuran

[0131] Measurement temperature: 40℃

[0132] Carrier flow rate: 1.0ml / min

[0133] Sample concentration: 0.1 mass%

[0134] Detector: RI (refractive index) detector

[0135] The acid dissociation constant pKa of the metal extractant is not particularly limited, and an appropriate value can be adopted depending on the type and number of the coordinating functional groups, etc. In the present invention, pKa is a value measured by a neutralization titration method.

[0136] The metal extractant can be synthesized by referring to a known method, for example, the method described in Patent Documents 1 and 2. For example, as a method for synthesizing the metal extractant, the synthesis method described in the Examples can be cited.

[0137] <Metal Extractant I>

[0138] Among the metal extractants, the metal extractant I is preferably a compound represented by the following formula (I).

[0139] The metal extractant I is a metal extractant having 2 to 6 nitrogen atoms and 2 Xs as coordinating functional groups, and its acid dissociation constant pKa is, for example, preferably 4 to 20, more preferably 5 to 15, and even more preferably 5 to 10.

[0140] [Chemical formula 4]

[0141]

[0142] In formula (I), R 1 represents an unsubstituted hydrocarbon group.

[0143] As can be used as R 1 The unsubstituted hydrocarbon group is not particularly limited and has the same meaning as the unsubstituted hydrocarbon group possessed by the terminal nitrogen atom. In particular, an unsubstituted branched alkyl group having 4 to 20 carbon atoms is preferred.

[0144] In formula (I), R 2 represents a substituent. 2 The substituent of is not particularly limited, and examples thereof include groups selected from the substituent Z described below, and preferably include alkyl, alkenyl, aralkyl, aryl, heteroatom-containing ring groups, etc. Among them, hydrocarbon groups such as alkyl, alkenyl, aralkyl, and aryl are preferred from the viewpoint of solubility in the oil phase. 2 The hydrocarbon group is not particularly limited and has the same meaning as the hydrocarbon group in the unsubstituted hydrocarbon group possessed by the terminal nitrogen atom. In addition, the hydrocarbon group may further have a group selected from the substituent Z as a substituent, but it is preferred that the carbon atom directly bonded to the nitrogen atom does not have a ketooxy group as a substituent, and it is more preferred to be an unsubstituted hydrocarbon group.

[0145] In the above formula (I), R 2 Middle and L3 The R of the bonded N 2 The unsubstituted hydrocarbon group has the same meaning as the unsubstituted hydrocarbon group possessed by the terminal nitrogen atom.

[0146] As R 2 More preferably, unsubstituted hydrocarbon groups are used as 3 The R of the bonded N 2 The unsubstituted hydrocarbon groups used may be respectively 1 The unsubstituted hydrocarbyl groups employed may be the same or different, but are preferably the same.

[0147] In the metal extractant I represented by formula (I), there are multiple R 2 In the case of multiple R 2 They may be the same or different, but are preferably the same.

[0148] In formula (I), X represents a coordination functional group, and represents a group selected from the following coordination functional group group G2. X is preferably a carboxyl group, a phosphoric acid group, a phosphonic acid group, a sulfonic acid group or a sulfinic acid group among the functional groups belonging to the coordination functional group group G2, and a carboxyl group is particularly preferred. The two Xs may be the same or different, but are preferably the same. The meaning of each coordination functional group included in the following coordination functional group group G2 is the same as the meaning of the corresponding coordination functional group included in the above-mentioned coordination functional group group G1.

[0149] <Coordinating functional group G2>

[0150] Carboxyl group, phosphoric acid group, phosphonic acid group, sulfonic acid group, sulfinic acid group, hydroxyl group.

[0151] In formula (I), L 1 , L 2 and L 3 Respectively represent linking groups. 1 , L 2 and L 3 The linking group is not particularly limited, and examples thereof include alkylene, alkenylene (preferably with 2 to 6 carbon atoms, more preferably with 2 to 3 carbon atoms), arylene (preferably with 6 to 24 carbon atoms, more preferably with 6 to 10 carbon atoms), oxygen atom, sulfur atom, imino (-NR N : R N The meaning of R 2), carbonyl, phosphate linking group (-OP(OH)(O)-O-), phosphonic acid linking group (-P(OH)(O)-O-) or groups related to their combination, etc. Here, the alkylene and alkenylene groups can be any of straight chain, branched chain, and cyclic chain, preferably straight chain or branched chain, and can also contain a cyclic chain (cyclic structure) in part of the straight chain or branched chain. The alkylene and alkenylene groups are preferably straight chains that do not contain cyclic chains, and are preferably straight chains in which the nitrogen atom in formula (I) is bonded to both ends of the longest carbon chain. In the groups related to the combination, the number of combined groups, linking groups or atoms is not particularly limited, for example, it can be set to 2 to 15, preferably 2 to 10, and more preferably 2 to 5. Furthermore, the number of types of combined groups, linking groups or atoms is not particularly limited, for example, it can be set to more than 2, preferably 2 to 5, and more preferably 2 or 3.

[0152] As can be used as L 1 Among the above, the linking group is preferably an alkylene group, preferably an alkylene group having 1 to 12 carbon atoms, more preferably an alkylene group having 1 to 6 carbon atoms, and further preferably an alkylene group having 1 to 4 carbon atoms. 1 The alkylene group is preferably a straight-chain alkylene group, more preferably a straight-chain alkylene group in which the nitrogen atom in formula (I) is bonded to both ends of the longest carbon chain, and further preferably 1,2-ethanediyl. 1 The alkylene group may have a substituent, but is more preferably an unsubstituted alkylene group.

[0153] In the metal extractant I represented by formula (I), there are multiple L 1 In the case of multiple L 1 They may be the same or different, but are preferably the same.

[0154] In addition, it can be used as L 1 In the linking group of 1 The carbon atom to which the nitrogen atom is directly bonded may have a ketooxy group as a substituent, but preferably does not have one.

[0155] As can be used as L 2 and L 3 The connecting group of L is preferably an alkylene group. 2 and L 3 The alkylene group may be any of linear, branched, and cyclic, preferably linear or branched, more preferably branched, and further preferably a branched (1,1-alkanediyl) in which a carbon atom at one end is bonded to N and X in formula (I) or a branched (1,2-alkanediyl) in which a carbon atom at one end and a carbon atom adjacent to the carbon atom are bonded to N and X in formula (I). 2 and L 3The number of carbon atoms in the alkylene group is not particularly limited, and can be, for example, 1 to 36. From the viewpoint of solubility in the oil phase, the number of carbon atoms in the alkylene group is preferably 4 to 30, more preferably 4 to 24, and even more preferably 6 to 20. 2 and L 3 The alkylene group is more preferably an unsubstituted alkylene group.

[0156] And, as can be used as L 2 and L 3 The linking group of L 2 and L 3 A group in which a part of the carbon atoms of the above-mentioned alkylene group are replaced by oxygen atoms is also one of the preferred embodiments. In this embodiment, the carbon atom substituted by the oxygen atom is a carbon atom located inside the carbon chain constituting the alkylene group, and the number of substituted carbon atoms is not particularly limited, and can be set to 1 to 3. As such a group, for example, a group in which one carbon atom in the above-mentioned alkylene group is replaced by an oxygen atom (alkylene-oxygen atom-alkyl group), a group in which two carbon atoms in the above-mentioned alkylene group are replaced by oxygen atoms (alkylene-oxygen atom-alkylene-oxygen atom-alkyl group, for example, the metal extractant E-6 synthesized in the example).

[0157] Can be used as L 2 and L 3 The linking groups of L may be the same or different from each other, but are preferably the same. 2 and L 3 The linker can be used with 1 The residue obtained by removing one hydrogen atom from the unsubstituted hydrocarbon group may be the same as or different from the residue obtained by removing one hydrogen atom from the unsubstituted hydrocarbon group. Preferably, the residue other than the portion where X in formula (I) is bonded to the nitrogen atom is the same as the residue that can be used as R. 1 The same as the unsubstituted hydrocarbon group.

[0158] In addition, it can be used as L 2 and L 3 In the linking group, none of the carbon atoms directly bonded to the nitrogen atom in formula (I) has a ketooxy group as a substituent.

[0159] In formula (I), -L 2 -X represented by the group and -L 3 The group represented by -X is a group having a coordinating functional group, L 2 , L 3 and X are as described above, but are preferably hydrocarbon groups having a coordination functional group. The hydrocarbon group having a coordination functional group is not particularly limited, and examples thereof include groups obtained by introducing a coordination functional group into an alkyl group, an alkenyl group, an aryl group, or a group formed by combining these groups. The above-mentioned alkyl group, alkenyl group, and aryl group respectively correspond to the hydrocarbon group that can be used as L before the introduction of the coordination functional group. 2The above-mentioned alkylene group, alkenylene group and arylene group. There are no particular restrictions on the combined group, and examples thereof include a group composed of a combination of an alkyl group and an aryl group.

[0160] In formula (I), -L 2 The group represented by -X is the same as that represented by -L 3 The groups represented by -X may be the same or different, but are preferably the same.

[0161] In formula (I), R 1 , R 2 , X and L 1 ~L 3 The combination of is not particularly limited, and combinations of respective preferred groups can be mentioned.

[0162] In formula (I), n is an integer of 1 to 5, preferably an integer of 1 to 4, and more preferably 1 or 2.

[0163] The metal extractant I may have a substituent other than the above-mentioned X. Examples of the substituent include groups selected from the substituent Z described below, but groups other than the coordinating functional groups included in the coordinating functional group group G1.

[0164] Specific examples of the metal extractant I include the organic compounds shown below in addition to the organic compounds synthesized in the Examples, but the present invention is not limited to these.

[0165] [Chemical formula 5]

[0166]

[0167] <Metal Extractant II>

[0168] Among the metal extractants, the metal extractant II is preferably a compound represented by the following formula (II).

[0169] The metal extractant II is a basic extractant having 2 to 6 nitrogen atoms (imino groups) as coordinating functional groups, and the acid dissociation constant pKa of its conjugate acid is preferably 5.0 to 14.0, more preferably 7.0 to 13.0. In the present invention, pKa is a value measured by neutralization titration.

[0170] [Chemical formula 6]

[0171]

[0172] In formula (II), R 3 ~R 5 and 3 ~R 5The unsubstituted hydrocarbon group is not particularly limited and has the same meaning as the unsubstituted hydrocarbon group possessed by the terminal nitrogen atom. In particular, an unsubstituted branched alkyl group having 4 to 20 carbon atoms is preferred. 3 ~R 5 The unsubstituted hydrocarbon groups may be the same or different, and are preferably the same.

[0173] In addition, R 5 In the case of R 6 The carbon atom to which the nitrogen atom is directly bonded does not have a ketooxy group as a substituent.

[0174] In formula (II), R 6 represents a substituent. 6 The substituent of is not particularly limited, and examples thereof include groups selected from the substituent Z described below, and preferably include alkyl, alkenyl, aralkyl, aryl, heteroatom-containing ring groups, etc. Among them, hydrocarbon groups such as alkyl, alkenyl, aralkyl, and aryl are preferred from the viewpoint of solubility in the oil phase. 6 The hydrocarbon group is not particularly limited and has the same meaning as the hydrocarbon group in the unsubstituted hydrocarbon group possessed by the terminal nitrogen atom. In addition, the hydrocarbon group may further have a group selected from the substituent Z as a substituent, but it is preferred that the carbon atom directly bonded to the nitrogen atom does not have a ketooxy group as a substituent, and it is more preferred to be an unsubstituted hydrocarbon group.

[0175] In the above formula (I), R 6 Zhong and R 5 The R of the bonded N 6 The unsubstituted hydrocarbon group has the same meaning as the unsubstituted hydrocarbon group possessed by the terminal nitrogen atom.

[0176] As R 6 More preferably, unsubstituted hydrocarbon groups are used as 5 The R of the bonded N 6 The unsubstituted hydrocarbon groups used may be respectively 3 ~R 5 The unsubstituted hydrocarbon groups in the alkyl group may be the same or different, but are preferably all the same, and are preferably all unsubstituted alkyl groups.

[0177] In the metal extractant II represented by formula (II), there are multiple R 6 In the case of multiple R 6 They may be the same or different, but are preferably the same.

[0178] In formula (II), L 4 Represents a linking group. 4The connecting group is not particularly limited, and examples thereof include alkylene (preferably having 1 to 12 carbon atoms, more preferably 1 to 6, and further preferably 1 to 4), alkenylene (preferably having 2 to 6 carbon atoms, more preferably 2 to 3), arylene (preferably having 6 to 24 carbon atoms, more preferably 6 to 10), oxygen atoms, sulfur atoms, imino (-NR N -:R N The meaning of R 2 ), carbonyl, phosphate linking group (-OP(OH)(O)-O-), phosphonic acid linking group (-P(OH)(O)-O-) or groups related to their combination, etc. Here, the alkylene and alkenylene groups can be any of straight chain, branched chain, and cyclic chain, preferably straight chain or branched chain, and can also contain a cyclic chain (cyclic structure) in part of the straight chain or branched chain. The alkylene and alkenylene groups are preferably straight chains that do not contain cyclic chains, and are preferably straight chains in which the nitrogen atom in formula (I) is bonded to both ends of the longest carbon chain. In the groups related to the combination, the number of combined groups, linking groups or atoms is not particularly limited, and for example, it can be set to 2 to 15, preferably 2 to 10, and more preferably 2 to 5. Furthermore, the number of types of combined groups, linking groups or atoms is not particularly limited, and for example, it can be set to more than 2, and preferably 2 or 3.

[0179] As can be used as L 4 The connecting group is preferably an alkylene group, preferably a straight-chain alkylene group, more preferably a straight-chain alkylene group in which the nitrogen atom in formula (II) is bonded to both ends of the longest carbon chain, and further preferably 1,2-ethanediyl. 4 The alkylene group may have a substituent, but is more preferably an unsubstituted alkylene group.

[0180] In the metal extractant II represented by formula (II), there are multiple L 4 In the case of multiple L 4 They may be the same or different, but are preferably the same.

[0181] In addition, the L 4 In the linking group, 3 and R 4 The carbon atom to which the nitrogen atom of the carbon atom is directly bonded does not have a ketooxy group as a substituent, but is bonded to a carbon atom having R 6 The carbon atom to which the nitrogen atom is directly bonded may have a ketooxy group as a substituent, but preferably does not have it.

[0182] In formula (II), R 3 and R 4 The amino group and the 5 and R 6 The amino groups may be the same or different, but are preferably the same.

[0183] In formula (II), R 3 ~R 6 and L 4 The combination of is not particularly limited, and combinations of respective preferred groups can be mentioned.

[0184] In formula (II), m is an integer of 1 to 5, preferably an integer of 1 to 4, and more preferably 1 or 2.

[0185] The metal extractant II may have a substituent, and examples of the substituent include a group selected from the substituent Z described below.

[0186] Specific examples of the metal extractant II include the organic compounds shown below in addition to the organic compounds synthesized in the Examples, but the present invention is not limited to these.

[0187] [Chemical formula 7]

[0188]

[0189] -Substituent Z-

[0190] is an alkyl group (preferably an alkyl group having 1 to 20 carbon atoms, for example, methyl, ethyl, isopropyl, tert-butyl, pentyl, heptyl, 1-ethylpentyl, benzyl, 2-ethoxyethyl, 1-carboxymethyl, etc.), an alkenyl group (preferably an alkenyl group having 2 to 20 carbon atoms, for example, vinyl, allyl, oleyl, etc.), an alkynyl group (preferably an alkynyl group having 2 to 20 carbon atoms, for example, ethynyl, butadiynyl, phenylethynyl, etc.), a cycloalkyl group (preferably a cycloalkyl group having 3 to 20 carbon atoms, for example, cyclopropyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, etc.), In the present invention, when an alkyl group is referred to, it generally means including a cycloalkyl group, but it is described separately here. ), aryl (preferably an aryl group having 6 to 26 carbon atoms, for example, phenyl, 1-naphthyl, 4-methoxyphenyl, 2-chlorophenyl, 3-methylphenyl, etc.), aralkyl (preferably an aralkyl group having 7 to 23 carbon atoms, for example, benzyl, phenethyl, etc.), heterocyclic group (preferably a heterocyclic group having 2 to 20 carbon atoms, more preferably a 5- or 6-membered heterocyclic group having at least one oxygen atom, sulfur atom, or nitrogen atom. The heterocyclic group includes aromatic heterocyclic groups and aliphatic heterocyclic groups. Heterocyclic group (for example, tetrahydropyranyl, tetrahydrofuranyl, 2-pyridyl, 4-pyridyl, 2-imidazolyl, 2-benzimidazolyl, 2-thiazolyl, 2-oxazolyl, pyrrolidonyl, etc.), alkoxy (preferably alkoxy having 1 to 20 carbon atoms, for example, methoxy, ethoxy, isopropoxy, benzyloxy, etc.), aryloxy (preferably aryloxy having 7 to 26 carbon atoms, for example, phenoxy, 1-naphthyloxy, 3-methylphenoxy, 4-methoxyphenoxy, etc.), heterocyclic oxy (a group in which -O- is bonded to the above heterocyclic group) , alkoxycarbonyl (preferably an alkoxycarbonyl having 2 to 20 carbon atoms, for example, ethoxycarbonyl, 2-ethylhexyloxycarbonyl, dodecyloxycarbonyl, etc.), aryloxycarbonyl (preferably an aryloxycarbonyl having 6 to 26 carbon atoms, for example, phenoxycarbonyl, 1-naphthyloxycarbonyl, 3-methylphenoxycarbonyl, 4-methoxyphenoxycarbonyl, etc.), heterocyclic oxycarbonyl (a group in which a -O-CO- group is bonded to the above heterocyclic group), amino (preferably an amino, alkylamino, arylamino having 0 to 20 carbon atoms, for example, amino (-NH 2), N,N-dimethylamino, N,N-diethylamino, N-ethylamino, anilino, etc.), sulfamoyl (preferably a sulfamoyl having 0 to 20 carbon atoms, for example, N,N-dimethylsulfamoyl, N-phenylsulfamoyl, etc.), acyl (including alkylcarbonyl, alkenylcarbonyl, alkynylcarbonyl, arylcarbonyl, heterocycliccarbonyl, preferably an acyl having 1 to 20 carbon atoms, for example, acetyl, propionyl, butyryl, octanoyl, hexadecanoyl, acryloyl, methacryloyl, crotonoyl, benzoyl, naphthoyl, nicotinoyl, etc.), acyloxy (including alkylcarbonyloxy, alkenylcarbonyloxy, alkynylcarbonyloxy, The heterocyclic carbonyloxy group is preferably an acyloxy group having 1 to 20 carbon atoms, for example, an acetyloxy group, a propionyloxy group, a butyryloxy group, an octanoyloxy group, a hexadecanoyloxy group, an acryloyloxy group, a methacryloyloxy group, a crotonyloxy group, a nicotinyloxy group, etc.), an aryloxy group (preferably an aryloxy group having 7 to 23 carbon atoms, for example, a benzoyloxy group, a naphthoyloxy group, etc.), a carbamoyl group (preferably a carbamoyl group having 1 to 20 carbon atoms, for example, N,N-dimethylcarbamoyl group, N-phenylcarbamoyl group, etc.), an acylamino group (preferably an acylamino group having 1 to 20 carbon atoms, for example, an acetylamino group, a benzoylamino group, etc.), an alkylthio group (preferably a 1-20 alkylthio groups, for example, methylthio, ethylthio, isopropylthio, benzylthio, etc.), arylthio groups (preferably arylthio groups having 6 to 26 carbon atoms, for example, phenylthio, 1-naphthylthio, 3-methylphenylthio, 4-methoxyphenylthio, etc.), heterocyclic thio groups (groups in which -S- groups are bonded to the above heterocyclic groups), alkylsulfonyl groups (preferably alkylsulfonyl groups having 1 to 20 carbon atoms, for example, methylsulfonyl, ethylsulfonyl, etc.), arylsulfonyl groups (preferably arylsulfonyl groups having 6 to 22 carbon atoms, for example, benzenesulfonyl, etc.), alkylsilyl groups (preferably alkylsilyl groups having 1 to 20 carbon atoms, for example, monomethylsilyl, silyl, dimethylsilyl, trimethylsilyl, triethylsilyl, etc.), arylsilyl (preferably arylsilyl having 6 to 42 carbon atoms, for example, triphenylsilyl, etc.), alkoxysilyl (preferably alkoxysilyl having 1 to 20 carbon atoms, for example, monomethoxysilyl, dimethoxysilyl, trimethoxysilyl, triethoxysilyl, etc.), aryloxysilyl (preferably aryloxysilyl having 6 to 42 carbon atoms, for example, triphenoxysilyl, etc.), phosphoryl (preferably phosphate having 0 to 20 carbon atoms, for example, -OP(=O)(R P ) 2 ), a phosphono group (preferably a phosphono group having 0 to 20 carbon atoms, for example, -P(=O)(R P ) 2 ), phosphinyl (preferably a phosphinyl group having 0 to 20 carbon atoms, for example, -P(R P ) 2), phosphonic acid group (preferably a phosphonic acid group having 0 to 20 carbon atoms, for example, -PO(OR P ) 2 ), sulfo group (sulfonic acid group), carboxyl group, hydroxyl group, sulfanyl group, cyano group, halogen atom (for example, fluorine atom, chlorine atom, bromine atom, iodine atom, etc.). P is a hydrogen atom or a substituent (preferably a group selected from the substituent Z).

[0191] Furthermore, each group listed in these substituents Z may be further substituted by the substituents Z described above.

[0192] The above-mentioned alkyl group, alkylene group, alkenyl group, alkenylene group, alkynyl group and / or alkynylene group etc. may be cyclic or chain-shaped, and may be straight-chain or branched.

[0193] [Method for separation and recovery of metal ions]

[0194] The separation and recovery method of metal ions of the present invention (hereinafter, sometimes referred to as the separation and recovery method of the present invention.) is a method for mixing an aqueous phase containing multiple metal ions and an oil phase containing a metal extractant of the present invention, thereby enabling the specific metal ions coordinated by the metal extractant of the present invention to be moved (extracted) from the aqueous phase to the oil phase, and to be separated and recovered with high selectivity and high recovery. Here, the metal ions extracted into the oil phase can be a part of the multiple metal ions contained in the aqueous phase, but can also be more than two kinds, or can be all kinds of heterogeneous metal ions contained in the aqueous phase. In the separation and recovery method of the present invention, as ions of valuable metal elements, more than two kinds of heterogeneous metal ions, for example, more than two kinds of metal ions belonging to the 4th family, the 7th family, the 9th family and the 10th family, and particularly preferably one kind of metal ion in cobalt ions and nickel ions as heterogeneous metal ions of the same period can be extracted into the oil phase with high selectivity and high recovery.

[0195] In the separation and recovery method of the present invention, it was found that the metal extractant of the present invention can extract two or more metal ions among the multiple metal ions present in the aqueous phase into the oil phase together, but can extract the characteristics and functions of one of the metal ions with high selectivity and high recovery rate, so it is suitable for the new use of separating and recovering two or more heterometallic metal ions.

[0196] <Water Phase>

[0197] The water forming the aqueous phase is not particularly limited, but (ultra)pure water, ion-exchanged water, and the like can be used.

[0198] The metal ions contained in the aqueous phase may include at least one metal ion belonging to Group 3 to Group 16, and may also include metal ions belonging to a group other than Group 3 to Group 16. In the present invention, it is preferred to include two or more metal ions belonging to Group 3 to Group 16, more preferably to include at least one ion of a transition metal element (a metal element belonging to Group 3 to Group 12), further preferably to include two or more metal ions belonging to Group 4 to Group 12, further preferably to include two or more metal ions belonging to Group 4 to Group 10, particularly preferably to include two or more metal ions belonging to Group 4, Group 7, Group 9 and Group 10, and most preferably to include two or more metal ions belonging to Group 8 to Group 10. The metal ions belonging to each group are not particularly limited, and are preferably metal ions belonging to Period 4 to Period 6 in the periodic table, and more preferably to Period 4 or Period 5. Furthermore, the number of types of metal ions is not particularly limited as long as it is 2 or more, and can be, for example, 2 to 15 types, preferably 2 to 8 types, and more preferably 2 to 5 types.

[0199] The combination of multiple metal ions is not particularly limited. For example, combinations of groups include a combination comprising group 9 and group 10 (except a combination comprising group 7), a combination comprising group 4 and group 9, a combination comprising group 7, group 9 and group 10, a combination comprising group 7, group 8, group 9 and group 10, and the like.

[0200] In the present invention, the metal ions belonging to each group may be two or more, but one is preferred from the viewpoint of exhibiting high selectivity.

[0201] Specific examples of the combination of metal ions include a combination containing Co and Ni (excluding a combination containing Mn), a combination containing Zr and Rh, a combination containing Mn, Co, and Ni, and a combination of Mn, Fe, Co, and Ni.

[0202] The metal elements belonging to each group are not particularly limited, and appropriate atoms can be used. For example, they are as follows.

[0203] As the metal element belonging to Group 3, Sc and Y are preferably mentioned.

[0204] Preferred examples of the metal element belonging to Group 4 include Ti, Zr and Hf.

[0205] Preferred examples of the metal element belonging to Group 5 include V, Nb and Ta.

[0206] As the metal element belonging to Group 6, Cr, Mo and W are preferably mentioned.

[0207] Preferred examples of the metal element belonging to Group 7 include Mn and Tc.

[0208] Preferred examples of the metal element belonging to Group 8 include Fe, Ru and Os.

[0209] Preferred examples of the metal element belonging to Group 9 include Co, Rh and Ir.

[0210] Preferred examples of the metal element belonging to Group 10 include Ni, Pd and Pt.

[0211] Preferred examples of the metal element belonging to Group 11 include Cu, Ag and Au.

[0212] Preferred examples of the metal element belonging to Group 12 include Zn, Cd and Hg.

[0213] Preferred examples of the metal element belonging to Group 13 include Al, Ga, In and Tl.

[0214] Preferred examples of the metal element belonging to Group 14 include Ge, Sn and Pb.

[0215] Preferred examples of the metal element belonging to Group 15 include Sb and Bi.

[0216] As the metal element belonging to Group 16, Te is preferably used.

[0217] As a plurality of metal ions, it is possible to prepare appropriately, for example, various metal salts (salts of inorganic acids such as nitric acid and sulfuric acid or organic acids such as acetic acid of typical elements), mixtures of metals (ions) from mining, recycled materials from metal waste, recycled materials from other wastes (such as recycled materials from waste batteries (LiB)), and mixtures thereof, etc. As recycled materials from waste LiB, recycled materials based on known methods such as wet treatment and electrolysis can be cited.

[0218] The total content of the plurality of metal ions in the aqueous phase is not particularly limited and can be appropriately set, and can be, for example, 1,000 to 1,000,000 mass ppm, preferably 1,000 to 100,000 mass ppm, and more preferably 1,000 to 80,000 mass ppm.

[0219] The total content of the metal ions belonging to Group 8 to Group 12 among the metal ions is not particularly limited and can be appropriately set, but can be, for example, 1,000 to 80,000 mass ppm, preferably 1,000 to 60,000 mass ppm.

[0220] The total content of metal ions belonging to Groups 3 to 7 and Groups 13 to 16 among the metal ions is not particularly limited and can be appropriately set, but can be, for example, 1,000 to 60,000 mass ppm, preferably 1,000 to 30,000 mass ppm.

[0221] The content of the metal ions belonging to each group is not particularly limited and can be appropriately set, but can be, for example, 1,000 to 60,000 mass ppm, preferably 1,000 to 50,000 mass ppm.

[0222] When metal ions belonging to a group other than Group 3 to Group 16 are contained, the content thereof is not particularly limited, and can be, for example, 50,000 mass ppm or less, and preferably 30,000 mass ppm or less.

[0223] When two or more metal ions belonging to each group are contained, the content of the metal ions belonging to each group is the total content.

[0224] In the present invention, the content of metal ions belonging to a certain group may be more or less than the content of metal ions belonging to other groups. In the separation and recovery method of the present invention, since metal ions can be separated and recovered with high selectivity, it is not necessary to set the content of metal ions belonging to different groups to a specific ratio. As an example, the mass ratio of the content of metal ions belonging to another group (for example, metal ions other than metal ions extracted with the maximum extraction amount (including unextracted metal ions)) to the content of metal ions belonging to a specific group (for example, metal ions extracted with the maximum extraction amount) [the content of metal ions belonging to a specific group: the content of metal ions belonging to another group] can be set to 100:1 to 10,000, preferably 100:10 to 5,000, more preferably 100:50 to 1,000, and further preferably 100:70 to 130.

[0225] The pH of the aqueous phase is not particularly limited and can be appropriately set, but if the solubility of metal ions, the formation of complex ions, etc. are taken into consideration, it is preferably set to 0.1 to 10, for example. The pH of the aqueous phase can be adjusted using an acid or a base, for example. As an acid, a known acid can be used without particular limitation, and inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, and organic acids such as formic acid, acetic acid, oxalic acid, organophosphoric acid, and organic sulfonic acid can be mentioned. As a base, a known base can be used without particular limitation, and inorganic bases and organic bases can be mentioned, preferably inorganic bases. As an inorganic base, for example, metal bases such as hydroxides and carbonates of metals of Group 1 or Group 2 can be mentioned, and further ammonia water, ammonium chloride, etc. can be mentioned. As an organic base, organic ammonium salts, etc. can be mentioned.

[0226] The temperature of the aqueous phase is not particularly limited, and can be, for example, 10 to 60°C.

[0227] The aqueous phase may contain a ligand (compound) coordinated to the metal ion or a compound generating a ligand, etc., as necessary.

[0228] The aqueous phase can be prepared by dissolving metal ions in water. The preparation conditions of the aqueous phase are not particularly limited. For example, the preparation temperature can be set to 10 to 60°C.

[0229] The aqueous phase may contain a masking agent in addition to the above-mentioned metal ions. The masking agent may be any known masking agent without particular limitation. Examples thereof include monodentate ligands such as ammonia, chelating agents such as dithizone, and the like.

[0230] <Oil phase>

[0231] In the separation and recovery method of the present invention, an oil phase (organic phase) containing one or two or more metal extractants of the present invention is used in place of the aqueous phase.

[0232] The metal extractant of the present invention exhibits solubility in an organic solvent and exists in the oil phase to coordinately bond with two or more metal ions existing near the interface between the aqueous phase and the oil phase, thereby exhibiting a function of moving the two or more metal ions into the oil phase. In the present invention, solubility in an organic solvent refers to the property that the metal extractant can be dissolved in an organic solvent in an amount described later.

[0233] The organic solvent forming the oil phase is not particularly limited, and any suitable organic solvent can be used. For example, alcohol solvents, ether solvents, hydrocarbon solvents (aromatic solvents, aliphatic solvents), halogen solvents, etc. are mentioned. Among them, hydrocarbon solvents are preferred, various solvents as petroleum diversion components are more preferred, and aromatics, paraffins, cycloalkanes, kerosene, gasoline, naphtha, kerosene, and light oil hydrocarbon solvents are further preferred.

[0234] The content of the metal extractant in the oil phase is appropriately set in consideration of the content of metal ions, the coordination amount to the metal ions, the number of coordinated functional groups, etc. For example, the content in the oil phase can be set to 20 to 10,000 millimoles / L (mM), preferably 50 to 1,000 millimoles / L, and more preferably 100 to 500 millimoles / L.

[0235] The temperature of the oil phase is not particularly limited, and can be, for example, 10 to 60°C.

[0236] The oil phase may contain appropriate components in addition to the metal extractant of the present invention.

[0237] The oil phase can be prepared by dissolving a metal extractant in an organic solvent. The conditions for preparing the oil phase are not particularly limited, and for example, the preparation temperature can be set to 10 to 60°C.

[0238] (Contact, Mixing)

[0239] In the separation and recovery method of the present invention, the water phase and the oil phase are mixed and allowed to stand.

[0240] The mixing conditions and standing conditions at this time are not particularly limited and can be appropriately set. For example, mixing can be carried out using various mixing devices. As mixing devices, there can be cited methods using a magnetic stirrer (stirrer tip), methods using a mechanical stirrer, and methods using a mixer, etc. The stirring conditions (stirring speed, stirring time, etc.) can be set appropriately according to the combination of metal ions and metal extractants, the mixing temperature, and the mixing device as long as they are conditions that can mix the aqueous phase and the oil phase (conditions for the metal extractant to coordinately bond with the metal ions). For example, the stirring time is not uniquely determined based on the stirring conditions, etc., but can be set to 10 minutes to 24 hours, for example.

[0241] The standing condition may be any condition as long as the water phase and the oil phase are separated into two layers. For example, the standing time can be set to 10 minutes to 24 hours after the mixing is stopped.

[0242] The mixing temperature and the standing temperature are not particularly limited either, and can be, for example, 10 to 60°C.

[0243] In the mixing of the aqueous phase and the oil phase, the mixing ratio of the aqueous phase and the oil phase is appropriately set according to the content (concentration) of the metal ions, the content (concentration) of the metal extractant, etc., and is not uniquely determined. For example, in the case of mixing the aqueous phase and the oil phase satisfying the above-mentioned concentrations, the oil phase can be set to a ratio of 50 to 2,000 mL relative to 100 mL of the aqueous phase, preferably 80 to 1,000 mL, and preferably 80 to 200 mmL. On the other hand, if the metal ions present in the aqueous phase are taken into consideration, the oil phase is preferably mixed at a ratio of 0.1 to 20 mole times the total content (moles) of the metal extractant relative to the metal ions. In addition, the content of the metal extractant relative to the total content of the metal ions that can be coordinated by the metal extractant (also referred to as the mixing amount. The ratio of the number of moles of the metal extractant to the total number of moles of the metal ions: molar ratio) can be set to, for example, 0.1 to 20.0 equivalents. Here, the metal ions that can be coordinated by the metal extractant refer to the metal ions that are coordinated by the metal extractant and extracted into the oil phase.

[0244] In the mixing of the aqueous phase and the oil phase, the pH of the mixed system can also be adjusted. Here, the pH set for the specific metal ion to be extracted is not unique, but is appropriately determined in consideration of the pKa of the metal extractant, the complex formation constant between the metal extractant and the metal ion, the coordination number of the metal ion, etc. As the pH of the mixed system, it is preferably set to 0.01 to 14, for example, it can also be set to 2 to 14, and preferably to 3 to 10. The preparation of pH can be carried out using the above-mentioned acid or base or their aqueous solutions, but it is preferred not to use ammonium ions.

[0245] When the pH of the mixed system is adjusted when the aqueous phase and the oil phase are mixed, the mixing of the aqueous phase and the oil phase and the standing of the mixed phase are performed after the pH is adjusted.

[0246] The two-phase separation fluid (solvent extraction phase, solvent extraction system) in which the aqueous phase and the oil phase are separated by mixing the aqueous phase and the oil phase and leaving them to stand in this way exists in a state where the aqueous phase and the oil phase are in contact with each other and separated in layers. Moreover, two or more metal ions coordinated and bonded by the metal extractant among the above-mentioned plurality of metal ions exist (move to) the oil phase. There are no particular restrictions on the two or more metal ions extracted into the oil phase from the plurality of metal ions. For example, two or more metal ions belonging to the 4th group, the 7th group, the 9th group and the 10th group can be cited. Specifically, a combination of the 9th group and the 10th group (excluding a combination including the 7th group), a combination of the 4th group and the 9th group, a combination of the 7th group, the 9th group and the 10th group, a combination including the 7th group, the 8th group, the 9th group and the 10th group, and the like. As a more specific combination of valuable metal elements, a combination of Co and Ni, a combination of Zr and Rh, a combination of Mn and Co, a combination with Mn, Co and Ni, and a combination of Mn, Fe, Co and Ni can be cited.

[0247] The number of types of metal ions extracted into the oil phase is not particularly limited as long as it is two or more, and can be, for example, 2 to 10 types, preferably 2 to 6 types, and more preferably 2 or 3 types.

[0248] By the simple method of mixing the above-mentioned aqueous phase and oil phase and letting them stand in the separation and recovery method of the present invention, it is possible to extract and separate and recover specific two or more metal ions among multiple metal ions with high selectivity and high recovery rate, and in particular, it is possible to extract ions of two or more metal elements and separate and recover one of the metal ions with high selectivity and high recovery rate.

[0249] A kind of metal ion that can be separated and recovered with high selectivity and high recovery rate is not uniquely determined according to the family or period of the metal ion, and the content, the type of metal extractant, etc. For example, when the metal ion belonging to the 9th family and the metal ion belonging to the 10th family are extracted into the oil phase, the metal ion belonging to the 9th family can be separated and recovered with high selectivity and high recovery rate, especially when Co ion is extracted as the metal ion belonging to the 9th family and Ni ion is extracted as the metal ion belonging to the 20th family, the Co ion can be separated and recovered with high selectivity and high recovery rate. And, when the metal ion belonging to the 7th family and the metal ion belonging to the 9th family are extracted into the oil phase, the metal ion belonging to the 7th family can be separated and recovered with high selectivity and high recovery rate. In addition, when the metal ion belonging to the 4th family and the metal ion belonging to the 9th family are extracted into the oil phase, the metal ion belonging to the 4th family can be separated and recovered with high selectivity and high recovery rate.

[0250] As described above, the separation and recovery method of the present invention can extract and recover two or more metal ions among the multiple metal ions present in the aqueous phase in the oil phase with high selectivity and high recovery rate. In particular, the separation and recovery method of the present invention can extract two or more metal ions and recover one of the metal ions with high selectivity and high recovery rate, so by further providing the aqueous phase containing the two or more metal ions extracted from the oil phase to the separation and recovery method of the present invention, the selectivity of one metal ion can be further improved without significantly damaging the recovery rate, and as a result, high-purity metal ions can be recovered with high recovery rate.

[0251] Such a separation and recovery method of the present invention can also be referred to as a method for extracting two or more metal ions.

[0252] The separation and recovery method of the present invention may have steps other than the step of mixing the above-mentioned aqueous phase and oil phase and letting it stand. For example, there can be cited a method of reversely extracting (separating) metal ions from the oil phase obtained in the step of mixing the aqueous phase and oil phase and letting it stand, a step of recovering the reversely extracted metal ions as compounds (salts), a step of purifying the reversely extracted metal ions or their compounds, and a step of pre-removing ions of metal elements belonging to Group 1 or Group 2 of the periodic table, etc. As a method for reversely extracting (separating) metal ions from the oil phase, a known method can be applied without particular restrictions. For example, it can be carried out by using an inorganic acid such as sulfuric acid, hydrochloric acid, nitric acid, etc., and setting the liquid phase to acidic, for example, pH 2 to 4. As a method for recovering the reversely extracted metal ions as compounds, a known method can be applied without particular restrictions.

[0253] <Separation and Recovery Method I of the Present Invention>

[0254] The separation and recovery method I of the present invention is a method in which the metal extractant I of the present invention is used as the metal extractant in the separation and recovery method of the present invention.

[0255] The separation and recovery method I of the present invention can be carried out in the same manner as the separation and recovery method of the present invention, but in the separation and recovery method I of the present invention, in the above range, from the viewpoint of selectivity and recovery rate, it is more preferred to set the pH of the aqueous phase to 0.5 to 8.0, and in particular, from the viewpoint of being able to improve the recovery rate, it is further preferably set to 3.0 to 8.0, and in particular, it is preferably set to 5.0 to 7.0. In the separation and recovery method I of the present invention, the pH of the mixed system of the aqueous phase and the oil phase is preferably set within the above range, but from the viewpoint of selectivity and recovery rate, it is more preferably set to 0.5 to 9.0, and in particular, from the viewpoint of being able to improve the recovery rate, it is further preferably set to 2.5 to 8.0, and in particular, it is preferably set to 4.0 to 7.0.

[0256] In the separation and recovery method I of the present invention, the metal extractant I can coordinate with the metal ions alone and extract the metal ions into the oil phase, so the aqueous phase and the oil phase may not contain compounds that coordinate with the metal ions and the like, which act synergistically with the metal extractant I in the extraction of the metal ions, such as known metal extractants. In the separation and recovery method of the present invention, an aqueous phase containing a plurality of metal ions as essential components and an oil phase containing a metal extractant as an essential component are usually used.

[0257] According to the separation and recovery method I of the present invention, two or more metal ions can be extracted and recovered in the oil phase with high selectivity and high recovery rate from a plurality of metal ions present in the aqueous phase, similarly to the separation and recovery method of the present invention.

[0258] <Separation and Recovery Method II of the Present Invention>

[0259] The separation and recovery method II of the present invention is a method in which the metal extractant II of the present invention is used as the metal extractant in the separation and recovery method of the present invention.

[0260] The separation and recovery method II of the present invention can be carried out in the same manner as the separation and recovery method of the present invention, and can extract and recover two or more metal ions from a plurality of metal ions present in the aqueous phase in the oil phase with high selectivity and high recovery rate.

[0261] The differences between separation and recovery method II of the present invention and the separation and recovery method of the present invention are described.

[0262] Metal extractant II is an amine (alkaline) extractant, so the metal ions extracted into the oil phase need to be negatively charged. Therefore, in the separation and recovery method II of the present invention, the aqueous phase contains a compound that forms a coordination complex (complex ion) with a negative charge by coordination with the metal ions, and the metal ions form a complex ion with a negative charge.

[0263] As such compounds, compounds in which the compound itself coordinates with metal ions to form a negatively charged complex ion, compounds in which anions generated by the compound coordinate with metal ions to form a negatively charged complex ion, etc. can be cited. As compounds that coordinate with metal ions, there are no particular limitations, and for example, chelating agents such as sodium nitrilotriacetic acid salt can be cited. In addition, as compounds that generate anions that coordinate with metal ions, metal salts of inorganic acids or organic acids such as nitrates, sulfates, and hydrochlorides, and halides can be cited. As halides, inorganic halides, organic halides, etc. can be cited. As inorganic halides, halides of typical elements (elements belonging to Group 1, Group 2, and Groups 12 to 18 of the periodic table) can be cited, and lithium chloride, sodium chloride, potassium chloride, etc. can be specifically cited.

[0264] The compound forming a complex ion is preferably a compound that generates an anion coordinated to a metal ion, and more preferably an inorganic halide.

[0265] The aqueous phase containing a compound that forms a coordination complex (complex ion) with a negative charge preferably contains anions generated (dissociated) from the compound, and more preferably contains halide ions. In addition, in the present invention, the aqueous phase containing anions and halide ions means that in addition to compounds that are dissolved in the aqueous phase and exist independently (free), it also contains compounds coordinated with metal ions.

[0266] The concentration of the compound in the aqueous phase is not particularly limited as long as complex ions can be formed, and can be, for example, 1 to 1000 g / L, preferably 10 to 300 g / L.

[0267] The content of the compound forming the negatively charged metal ion in the aqueous phase (including the compound coordinated with the metal ion, which has the same meaning as the amount added in the aqueous phase.) is not particularly limited as long as it can coordinate with the metal ion to form a negatively charged complex ion, and can be appropriately set in consideration of the content of the metal ion, the coordination amount with the metal ion, the number of coordinated functional groups, etc. The content of the above-mentioned compound can be set to 10 to 10,000 parts by mass, preferably 100 to 1,000 parts by mass, relative to 100 parts by mass of the total content of the metal ions (including uncoordinated metal ions) contained in the aqueous phase. In addition, the content of the above-mentioned compound can be set to 0.1 to 100 moles, preferably 1.0 to 100 moles, relative to the total content (moles) of the metal ions (including uncoordinated metal ions) contained in the aqueous phase. On the other hand, as the content of the above-mentioned compound relative to the total content of the metal ions (mixing amount: molar ratio), for example, it can be set to 0.1 to 100 equivalents, preferably 1.0 to 50 equivalents.

[0268] The aqueous phase can be prepared by dissolving the metal ions and the above-mentioned compound in water, or by mixing an aqueous solution in which the metal ions are dissolved and an aqueous solution in which the above-mentioned compound is dissolved. In order to coordinate the above-mentioned compound with at least one of the metal ions, the preparation of the aqueous phase is preferably carried out at a preparation temperature of 10 to 60° C. and a pH of 0.1 to 10 for 10 minutes to 6 hours. The above-mentioned acid or base can be used to adjust the pH.

[0269] The separation and recovery method II of the present invention can be carried out in the same manner as the separation and recovery method of the present invention, except that complex ions of metal ions are formed in the aqueous phase. However, in the separation and recovery method II of the present invention, within the above range, from the viewpoint of selectivity and recovery rate, it is more preferred to set the pH of the aqueous phase to 0.5 to 7, and particularly from the viewpoint of being able to improve the recovery rate, it is further preferably set to 3.0 to 7.0. In the separation and recovery method II of the present invention, the pH of the mixed system of the aqueous phase and the oil phase is preferably set within the above range, but from the viewpoint of selectivity and recovery rate, it is more preferred to set it to 0.01 to 5.5, particularly from the viewpoint of being able to improve the recovery rate, it is further preferably set to 0.1 to 4.5, and particularly preferably set to 0.1 to 3.5.

[0270] In the separation and recovery method II of the present invention, the metal extractant II coordinates with the metal ions that form complex ions and can extract the metal ions into the oil phase. Therefore, the aqueous phase and the oil phase may not contain compounds related to the extraction of metal ions, such as known metal extractants, in addition to the compound that coordinates with the metal ions to form complex ions and the metal extractant II.

[0271] In the separation and recovery method II of the present invention, a plurality of metal ions and compounds forming complex ions thereof are generally contained as essential components, and an aqueous phase containing complex ions of metal ions and an oil phase containing a metal extractant II as essential components are used.

[0272] According to the separation and recovery method II of the present invention, two or more metal ions can be extracted and recovered in the oil phase with high selectivity and high recovery rate from among a plurality of metal ions present in the aqueous phase, similarly to the separation and recovery method of the present invention.

[0273] Example

[0274] The present invention will be described in further detail below with reference to the Examples, but the present invention is not limited thereto. In the following Examples, "parts" and "%" indicating the composition are by mass unless otherwise specified.

[0275] [Synthesis and preparation of metal extractants]

[0276] The metal extractants shown below were synthesized or prepared.

[0277] In the metal extractants E-6 and T-5 described below, "Me" represents a methyl group.

[0278] [Chemical formula 8]

[0279]

[0280] PC-88A: (2-ethylhexyl)phosphonic acid mono-2-ethylhexyl (manufactured by Tokyo Chemical Industry Co., Ltd.) shown below

[0281] [Chemical formula 9]

[0282]

[0283] VA-10: Versatic acid 10 (manufactured by HEXION)

[0284] EDTA: Ethylenediaminetetraacetic acid, manufactured by DOJINDO LABORATORIES

[0285] Tris-2-EHA: tris(2-ethylhexyl)amine (manufactured by BASF Corporation) shown below

[0286] [Chemical formula 10]

[0287]

[0288] <Synthesis of Metal Extractant E-1>

[0289] Metal extractant E-1 was synthesized as follows.

[0290] That is, 305 g of ethanol and 46.0 g of sodium ethoxide (manufactured by FUJIFILM Wako Pure Chemical Corporation) were added to a 1L three-necked eggplant flask and stirred thoroughly. 97.5 g of diethyl malonate, 112 g of 1-bromo-2-ethylhexane and 126 g of ethanol were added and stirred for 6 hours under reflux. The obtained solution was passed through a Buchner funnel, and after the filtrate was concentrated, 200 mL of 2M hydrochloric acid was added. The obtained solution was extracted with 500 mL of ethyl acetate and dried with sodium sulfate. After removing the sodium sulfate, the solvent was concentrated.

[0291] The obtained compound was added to a 2L three-necked eggplant flask, and 550g of ethanol and 715g of a 4M (mol / L) NaOH aqueous solution were added, followed by stirring under reflux for 7 hours. After cooling at room temperature, the solution was extracted with xylene to obtain a xylene solution.

[0292] The obtained xylene solution was added to a 1 L three-necked eggplant flask and stirred under reflux for 8 hours. After cooling at room temperature, 1 M NaOH aqueous solution and water were added, and after extraction with toluene, the solvent was distilled off under reduced pressure to obtain Compound A.

[0293] After adding 35.0 g of the obtained compound A and 121 g of thionyl chloride to a 500 mL three-necked flask, the mixture was stirred at an internal temperature of 55° C. for 2 hours. 97.4 g of bromine was added, and the mixture was further stirred at an internal temperature of 55° C. for 5 hours. After thionyl chloride and bromine were distilled off under reduced pressure, ice water was added, and the mixture was extracted with toluene, and the solvent was distilled off under reduced pressure, thereby obtaining compound B.

[0294] 5.0 g of the intermediate I-1, 33.3 g of ethanol, 16.7 g of water, and 8.3 g of NaOH were added to a 300 mL three-necked eggplant flask and stirred under reflux. After 1 hour, a solution obtained by dissolving 13.3 g of compound B in 25.0 g of ethanol was added dropwise, and the mixture was stirred for 36 hours. After the solution was allowed to stand at room temperature, hydrochloric acid was added to neutralize the mixture to pH 3 to 4. The obtained solution was extracted with toluene, and the solvent was distilled under reduced pressure to obtain 6.5 g (yield 59%) of yellow liquid metal extractant E-1.

[0295] <Synthesis of Intermediate I-1>

[0296] 20.0 g of ethylenediamine, 350 g of ethanol, and 87.5 g of 2-ethylhexanal were added to a 1L three-necked eggplant flask, and stirred at room temperature for 5 hours. After adding 37.8 g of sodium borohydride while cooling the reaction solution in an ice bath, the ice bath was removed and stirred at room temperature for 1 hour. While cooling the reaction solution in an ice bath, an ammonium chloride solution was added until foaming stopped, and the ethanol was distilled off under reduced pressure. The obtained solution was extracted with toluene, and the solvent was distilled off under reduced pressure, thereby obtaining intermediate I-1 (N, N'-bis (2-ethylhexyl) ethane-1,2-diamine) with a yield of 98%.

[0297] The metal extractant E-1 thus synthesized was identified as follows.

[0298] That is, E-1 was dissolved in deuterated chloroform and the 1 H-NMR (equipment: BLUKER400), and the obtained graph is shown in Figure 1 Then, the metal extractant E-1 was mixed with KBr and subjected to FT-IR measurement. The obtained graph is shown in Figure 2 .

[0299] exist Figure 1 shown 1In the H-NMR chart, peaks derived from diastereomers were confirmed at chemical shifts of 63.5 to 4.0 ppm. Therefore, it is inferred that at least two asymmetric centers derived from 2-ethylhexyl groups were introduced into the compound. In addition, it can be seen that the peak (δ0.89) derived from the terminal methyl group of 2-ethylhexyl groups is equivalent to 24H relative to the integral value 4H of the peak (δ3.39) derived from the methylene group located between the two N atoms of ethylenediamine. Therefore, it can be seen that four 2-ethylhexyl groups were introduced.

[0300] And, in Figure 2 In the FT-IR chart shown, it is estimated that the -1 The broad peak observed nearby is derived from the OH stretching of the carboxyl group.

[0301] Based on the above, the obtained compound was identified as having the structure shown in the above E-1.

[0302] <Synthesis of Metal Extractant E-2>

[0303] Metal extractant E-2 was synthesized in the same manner as in the synthesis of metal extractant E-1, except that 1-bromo-2-ethylhexane was replaced with 1-bromo-3-ethylheptane. The obtained metal extractant E-2 was identified in the same manner as in the synthesis of metal extractant E-1.

[0304] <Synthesis of Metal Extractant E-3>

[0305] Metal extractant E-3 was synthesized as follows.

[0306] Specifically, 25.0 g of 1,2-dibromoethane and 129 g of di(2-ethylhexyl)amine were added to a 300 mL three-necked eggplant flask, and stirred for 10 hours at an internal temperature of 100° C. Excess di(2-ethylhexyl)amine was distilled off under reduced pressure from the obtained solution to obtain metal extractant E-3 at a yield of 85%.

[0307] The metal extractant E-3 thus synthesized was identified as follows.

[0308] That is, the metal extractant E-3 was dissolved in deuterated chloroform and the 1 H-NMR (equipment: BLUKER400), and the obtained graph is shown in Figure 3 Furthermore, fragment ions of the compound were detected by GC-MS (device: GCMS-QP2010).

[0309] It is known that Figure 1 shown 1In the H-NMR chart, the peaks (δ2.11, δ1.26, δ0.89) derived from the 2-ethylhexyl group correspond to 8H, 36H, and 24H, respectively, with respect to the integrated value 4H of the peak (δ2.46) derived from the methylene group located between the two N atoms of ethylenediamine. Therefore, it can be seen that four 2-ethylhexyl groups are introduced. In addition, the fragment of m / z254 obtained by GC-MS is estimated to be the following structure.

[0310] Based on the above, it was identified that the obtained compound had the structure shown in the above E-3.

[0311] [Chemical formula 11]

[0312]

[0313] <Synthesis of Metal Extractant E-4>

[0314] Metal extractant E-4 was synthesized in the same manner as in the synthesis of metal extractant E-3, except that di(2-ethylhexyl)amine was replaced with dinonylamine. The obtained metal extractant E-4 was identified in the same manner as in the synthesis of metal extractant E-3.

[0315] <Synthesis of Metal Extractant E-5>

[0316] Metal extractant E-5 was synthesized in the same manner as in the synthesis of metal extractant E-3, except that 1,2-dibromoethane was replaced with 1,4-bis(bromomethyl)cyclohexane. The obtained metal extractant E-5 was identified in the same manner as in the synthesis of metal extractant E-3.

[0317] <Synthesis of Metal Extractant E-6>

[0318] Metal extractant E-6 was synthesized in the same manner as in the synthesis of metal extractant E-1, except that 1-bromo-2-ethylhexane was replaced with 1-bromo-3-(2-methoxyethoxy)propane. The obtained metal extractant E-6 was identified in the same manner as in the synthesis of metal extractant E-1.

[0319] <Synthesis of Metal Extractant T-1>

[0320] According to the method described in Japanese Patent Application Laid-Open No. 2016-028021, metal extractant T-1 was synthesized and identified.

[0321] <Synthesis of Metal Extractant T-2>

[0322] Metal extractant T-2 was synthesized according to the synthesis method of D2EHAG described in Japanese Patent Application Laid-Open No. 2014-205900.

[0323] <Synthesis of Metal Extractant T-3>

[0324] Metal extractant T-3 was synthesized in the same manner as in the synthesis of metal extractant E-1, except that intermediate I-1 was changed to ethylene glycol. The obtained metal extractant T-3 was identified in the same manner as in the synthesis of metal extractant E-1.

[0325] <Synthesis of Metal Extractant T-4>

[0326] In the synthesis of metal extractant E-3, except that di(2-ethylhexyl)amine was replaced with 2-ethylhexanol and 60.0 g of sodium hydroxide was added, metal extractant T-4 was synthesized in the same manner as in the synthesis of metal extractant E-3. The obtained metal extractant T-4 was identified in the same manner as in the synthesis of metal extractant E-3.

[0327] <Synthesis of Metal Extractant T-5>

[0328] Metal extractant T-5 was synthesized in the same manner as in the synthesis of metal extractant E-1, except that 2-ethylhexanal was replaced with 3-(methylthio)butyraldehyde in the synthesis of intermediate I-1 in the synthesis of metal extractant E-1. The obtained metal extractant T-5 was identified in the same manner as in the synthesis of metal extractant-1.

[0329] Table 1-2 shows the molecular weights of the synthesized or prepared metal extractants and the pKa values ​​calculated by the above-mentioned method.

[0330] [Preparation of aqueous solution containing metal ions]

[0331] <Preparation of an aqueous solution (aqueous phase) containing metal ions used in separation and recovery method I using metal extractant I>

[0332] 95.4 g of cobalt sulfate (II) heptahydrate (manufactured by FUJIFILM Wako Pure Chemical Corporation) and 95.7 g of nickel (II) sulfate heptahydrate (manufactured by FUJIFILM Wako Pure Chemical Corporation) were added to a 1 L volumetric flask, dissolved in ultrapure water, and stirred and dissolved at 30°C to prepare a metal ion-containing aqueous solution (W1) containing two types of metal ions.

[0333] Then, each sulfate was dissolved in ultrapure water with the combination of metal ions shown in Table 1-1 to prepare aqueous solutions (W2) and (W3) containing two or three metal ions.

[0334] <Preparation of Aqueous Solution (Aqueous Phase) Containing Metal Ions Used in Separation and Recovery Method II Using Metal Extractant II>

[0335] 200 g of lithium chloride (manufactured by FUJIFILM Wako Pure Chemical Corporation), 95.4 g of cobalt sulfate (II) heptahydrate (manufactured by FUJIFILM Wako Pure Chemical Corporation), and 95.7 g of nickel sulfate (II) heptahydrate (manufactured by FUJIFILM Wako Pure Chemical Corporation) were added to a 1 L volumetric flask, dissolved with ultrapure water, and stirred and dissolved at 30° C., thereby preparing a metal ion-containing aqueous solution (W4) containing two kinds of metal ions. In this aqueous solution, the two kinds of metal ions (cobalt and nickel) form complex ions coordinated with halide ions.

[0336] <Preparation of Metal Extractant Solution (Oil Phase)>

[0337] Each synthesized or prepared metal extractant was added to a 100 mL volumetric flask, and the volume was fixed using kerosene (manufactured by FUJIFILM WakoPure Chemical Corporation) at room temperature to prepare metal extractant solutions (Y1) to (Y6) and (Yc1) to (Yc9) (concentration 310 mM) containing each metal extractant.

[0338] In addition, the metal extractant EDTA was not soluble in kerosene, and the metal extractant solution (Yc4) could not be prepared.

[0339] [Examples 1 to 4, 8: Separation and Recovery Method I Using Metal Extractant I and Comparative Examples 1 to 6, 9]

[0340] <Example 1>

[0341] In a 30 mL vial, 12 mL of the extractant solution (Y1) was added to 10 mL of the prepared aqueous solution (W1) containing metal ions, and stirred at 25°C for 30 minutes through a stirrer tip. At this time, the mixing amount (unit: equivalent) of the metal extractant relative to the total content of the coordinated metal ions (the same meaning as the extracted metal ions, Co and Ni in Example 1) was 0.5. Then, 10M sodium hydroxide aqueous solution or 10M hydrochloric acid was added to adjust the pH of the mixed solution to the value shown in the "pH when mixed" column of Table 1-2, and after further stirring at 25°C for 30 minutes, it was allowed to stand at the same temperature for 1 hour. Confirm that it is separated into two layers, the organic phase (oil phase) and the aqueous phase, and the liquid is separated and the aqueous phase is taken out, thereby separating and recovering the metal ions. The metal ions extracted in Example 1 and the metal ions with the maximum extraction amount are shown in the "Type" column and the "Maximum Extraction Amount" column of the "Extracted Metal Ions" column of Table 1-2, respectively.

[0342] <Examples 2 to 4, 8 and Comparative Examples 1 to 6, 9>

[0343] In Example 1, the metal ion-containing aqueous solution and the extractant solution were changed to the combination shown in Table 1-1 and Table 1-2 (hereinafter collectively referred to as Table 1), the pH when the aqueous phase and the oil phase were mixed was set to the value shown in the "pH when mixed" column of Table 1-2, and the mixing amount (unit: equivalent) of the metal extractant relative to the total content of the coordinated metal ions was set to the value shown in the "mixing amount" column of Table 1-2, and the metal ions of Examples 2 to 4, 8 and Comparative Examples 1 to 6, 9 were separated and recovered in the same manner as in Example 1. In each example, the extracted metal ions and the metal ions with the maximum extraction amount are respectively shown in the "Type" column and the "Maximum extraction amount" column of the "Extracted metal ions" column of Table 1-2.

[0344] In Comparative Example 4 using the metal extractant solution (Yc4), metal ions could not be extracted into the oil phase. Therefore, "-" is indicated in the "Extracted Metal Ions" column and the "Selection Ratio" column in Table 1-2.

[0345] [Examples 5 to 7: Separation and Recovery Method II Using Metal Extractant II and Comparative Examples 7 and 8]

[0346] <Example 5>

[0347] In a 30 mL vial, 12 mL of extractant solution (Y3) was added to 10 mL of the prepared aqueous solution (W4) containing metal ions, and stirred at 25°C for 30 minutes through the tip of the stirrer. At this time, the mixing amount of the metal extractant relative to the total content of the metal ions (unit: equivalent) was 0.5. Then, 10 M sodium hydroxide aqueous solution or 10 M hydrochloric acid was added to adjust the pH of the mixed solution to the value shown in the "pH when mixed" column of Table 1-2, and after further stirring at 25°C for 30 minutes, it was allowed to stand at the same temperature for 1 hour. Confirm that it is separated into two layers, the organic phase (oil phase) and the aqueous phase, and the liquid is separated and the aqueous phase is taken out, thereby separating and recovering the metal ions. The metal ions extracted in Example 5 and the metal ions with the maximum extraction amount are shown in the "Type" column and the "Maximum Extraction Amount" column of the "Extracted Metal Ions" column of Table 1-2, respectively.

[0348] <Examples 6, 7 and Comparative Examples 7, 8>

[0349] In Example 5, the aqueous solution containing metal ions and the extractant solution were changed to the combination shown in Table 1, and the pH of the aqueous phase and the oil phase when mixed was set to the value shown in the "pH when mixed" column of Table 1-2, and the mixture was allowed to stand. The metal ions of Examples 6 and 7 and Comparative Examples 7 and 8 were separated and recovered in the same manner as in Example 5. In each example, the extracted metal ions and the maximum amount of the metal ions are shown in the "Type" column and the "Maximum Extraction Amount" column of the "Extracted Metal Ions" column of Table 1-2, respectively.

[0350] For each aqueous phase used in the embodiment and the comparative example and each aqueous phase after extraction, pH was measured using a pH meter (SK-620pHII, manufactured by SATOTECH), and the content of dissolved metal ions was quantified using an inductively coupled plasma emission spectrometry (ICP-OES) device (Optima 7300D (trade name), manufactured by PerkinElmer Co., Ltd.). The measured values ​​of the pH of each aqueous phase used in the embodiment and the comparative example and the content of dissolved metal ions in each aqueous phase are shown in the "Aqueous Phase pH" column of Table 1-2 and the "Metal Ion Concentration (ppm)" column of Table 1-1, respectively. The extraction amount (ppm) of the metal ion of the maximum extraction amount measured in this way is divided by the total extraction amount (ppm) of other metal ions, and the result of calculating the ratio of the extraction amount is shown in the "Selection Ratio" column of Table 1-2.

[0351] In the Examples and Comparative Examples, the results of measuring the pH of the aqueous phase and the oil phase when mixed in the same manner are shown in the "pH when mixed" column. In addition, the mixing amount of the metal extractant relative to the total content of the metal ions that can be coordinated is shown in each "mixing amount" column of Table 1-2. In Table 1-2, the unit of the mixing amount is equivalent, but it is omitted.

[0352] In addition, the present experiment was conducted in the same manner as in Examples 1 to 8 and Comparative Examples 1 to 9 except that the metal ion concentration of the water layer was reduced to 1 / 5. As a result, the same results were obtained.

[0353] [Table 1]

[0354] Table 1-1

[0355]

[0356] [Table 2]

[0357] Table 1-2

[0358]

[0359] The following can be seen from the comparison results of "metal ion concentration (ppm) in the aqueous phase before extraction" and "metal ion concentration (ppm) in the aqueous phase after extraction" shown in Table 1.

[0360] When metal ions were separated and recovered from the aqueous phase, Comparative Examples 1 to 3 using PC-88A, VA-10 and T-1 as conventional metal extractants were able to extract only three metal ions present in the aqueous solution (W2) containing metal ions into the oil phase. However, with regard to Mn ions, although the recovery amount was high, relatively large amounts of Co and Ni were also extracted, so the selectivity of the maximum amount of Mn ions extracted was low as shown in the "Selectivity" column of Table 1-2. In addition, as described above, Comparative Example 4 using EDTA as a metal extractant was even unable to extract metal ions. And, similarly, Comparative Examples 5 to 9 using metal extractants T-2 to T-4, T-5 and Tris-2-EHA all resulted in low selectivity for the maximum amount of metal ions extracted. In particular, the maximum amount of metal ions extracted in Comparative Example 8 was also insufficient.

[0361] In contrast, Examples 1 to 8 using the metal extractant I or II of the present invention can extract two metal ions from the metal ions present in the aqueous solution containing metal ions into the oil phase. Moreover, the metal ions with the largest amount of extraction (Examples 1 and 4 to 8: Co ions, Example 2: Mn ions, Example 3: Zr ions) can be extracted from the aqueous phase to the oil phase with high selectivity in almost all amounts with respect to metal ions other than the metal ions with the largest amount of extraction. In particular, Examples 1 and 4 to 8 show that while extracting both Co ions and Ni ions, which are important in manufacturing lithium ion batteries, one metal ion, Co ions, can be recovered with high selectivity and high recovery rate from these metal ions of the same period and from different families with similar physical and chemical behaviors. In this way, it is considered that the acidic metal extractant of the present invention exhibits a unique function of selectively coordinating with a specific metal ion, preferably two or more metal ions belonging to different families, from a plurality of metal ions present in the aqueous phase, especially two or more metal ions belonging to different families. As a result, it was discovered for the first time that a plurality of metal ions, in particular one metal ion belonging to Group 9 and Group 10 that can be separated and recovered with high selectivity and high recovery rate from waste LiB.

[0362] Based on the above results, it can be seen that by reverse extraction of the oil phase obtained in the above embodiments under conventional methods and conditions, the metal ions in the oil phase extracted with high selectivity and high recovery can be easily separated and recovered with high recovery without compromising the high selectivity.

[0363] In the technology of reclaiming specific metal ions from the aqueous phase containing multiple metal ions, it is usually difficult to reclaim specific metal ions with high selectivity and recovery rate. When maintaining high selectivity, the recovery rate decreases, so in order to realize the specified recovery rate, it is actually necessary to separate and recover operations multiple times. In contrast, the present invention can extract almost all amounts of 1 of 2 kinds of heterogeneous metal ions from the aqueous phase to the oil phase with high selectivity by a simple method. Therefore, from the consideration of reclaiming a kind of metal ion with high recovery rate and further improving selectivity from the obtained oil phase by reverse extraction process etc., in view of the above-mentioned actual situation, the technical significance of the present invention is also large.

[0364] The present invention has been described together with its embodiments, but unless otherwise specified, the present invention is not intended to be limited to any of the details described, and it is considered that it should be widely interpreted within the scope without departing from the spirit of the invention as shown in the appended claims.

[0365] This application claims priority based on Japanese patent application No. 2022-147027 filed in Japan on September 15, 2022, which are hereby incorporated by reference, and the contents thereof are incorporated into this specification as a part of what is described in this specification.

Claims

1. A metal extractant that extracts metal ions present in an aqueous phase into an oil phase, In the metal extractant, the nitrogen atoms located at both ends of the molecular chain constituting the metal extractant do not form a carbamoyl bond, and have an unsubstituted hydrocarbon group, and as a coordinating functional group (α) for the extracted metal ion, a group containing any coordinating functional group in the following coordinating functional group group G1 or an unsubstituted hydrocarbon group, <Coordinating functional group G1> Hydroxyl group, ether group, thiol group, thioether group, nitrile group, isonitrile group, carboxyl group, amino group, amide group, phosphoric acid group, phosphonic acid group, sulfonic acid group, sulfinic acid group, phosphine group, nitrogen-containing heterocycle, oxygen-containing heterocycle, sulfur-containing heterocycle.

2. The metal extractant according to claim 1, wherein The group including the coordinating functional group is a hydrocarbon group having a coordinating functional group.

3. The metal extractant according to claim 1, wherein At least one of the coordinating functional groups is selected from a carboxyl group, a phosphoric acid group, a phosphonic acid group, a sulfonic acid group and a sulfinic acid group. 4 . The metal extractant according to claim 1 , which is used for extracting and separating metal ions of two or more elements belonging to different groups of the periodic table among the metal ions.

5. The metal extractant according to claim 1, wherein The metal extractant is represented by the following formula (I): Formula (I) In formula (I), R 1 represents an unsubstituted hydrocarbon group, R 2 represents a substituent, wherein L 3 The R of the bonded N 2 represents an unsubstituted hydrocarbon group, X each independently represents a group selected from the following coordination functional group group G2, L 1 , L 2 and L 3 Each independently represents a linking group, n is an integer from 1 to 5, <Coordinating functional group G2> Carboxyl group, phosphoric acid group, phosphonic acid group, sulfonic acid group, sulfinic acid group, hydroxyl group.

6. The metal extractant according to claim 5, wherein The X is a carboxyl group, a phosphoric acid group, a phosphonic acid group, a sulfonic acid group or a sulfinic acid group.

7. The metal extractant according to claim 1, wherein The metal extractant is represented by the following formula (II): Formula (II) In formula (II), R 3 ~R 5 Each independently represents an unsubstituted hydrocarbon group, R 6 represents a substituent, wherein, with R 5 The R of the bonded N 6 represents an unsubstituted hydrocarbon group, L 4 Represents a connecting base, m is an integer of 1-5.

8. A method for separating and recovering metal ions, comprising mixing an aqueous phase containing a plurality of metal ions and an oil phase containing the metal extractant according to any one of claims 1 to 7.

9. The separation and recovery method according to claim 8, wherein: When the oil layer contains the metal extractant according to claim 7, the aqueous phase contains halide ions.

10. The separation and recovery method according to claim 8, wherein: Among the plurality of metal ions, two or more metal ions belonging to different groups of the periodic table are extracted from the aqueous phase into the oil phase and recovered.

11. The separation and recovery method according to claim 10, wherein: The metal ions of the two or more elements are metal recyclables from waste batteries.

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