Aminogroup-containing bidentate ligand, its preparation method and use

Abstract

This invention discloses an amino-containing bidentate ligand, its preparation method, and its application, belonging to the field of hydrometallurgical technology. The amino-containing bidentate ligand provided by this invention has a connected pyridine ring and a pyrazole ring, with an R group attached to the pyrazole ring; wherein the pyridine ring and the R group are located at the meta position of the pyrazole ring and are both connected to a C atom. Because the amino-containing bidentate ligand provided by this invention has a protonated amino group vacated, the organic phase obtained when combined with an extractant can solve the technical problems of low organic phase extraction capacity, low nickel-cobalt selectivity and priority, and short organic phase life in traditional solvent extraction and separation of nickel and cobalt. This invention also provides a preparation method and application of the above-mentioned bidentate ligand.

Description

Technical Field

[0001] This invention relates to the field of hydrometallurgical technology, and in particular to an amine-containing bidentate ligand, its preparation method, and its application. Background Technology

[0002] Nickel and cobalt, as important non-ferrous metals, are widely used in permanent magnets, alloys, and catalysts. Currently, with the rise of new energy vehicles, lithium-ion battery production is gradually shifting from 3C consumer batteries to power batteries, and their production and consumption are increasing daily. As important raw materials for ternary polymer lithium-ion battery cathode materials (NCM), the demand for nickel and cobalt is also increasing. Currently, the main source of nickel and cobalt is the hydrometallurgical smelting of laterite nickel ore. With the promotion of electric vehicles and the passage of time, the number of retired lithium-ion batteries will increase year by year. Recycling retired lithium-ion batteries as secondary resources can effectively avoid environmental pollution and waste of valuable metals. Therefore, waste lithium-ion batteries are gradually becoming a source of nickel and cobalt. However, the composition of secondary resources such as laterite nickel ore and retired lithium-ion batteries is complex. After acid leaching, other interfering metal impurities will enter the leaching solution, increasing the difficulty of separating and extracting nickel and cobalt. This increases the process flow, energy consumption, production costs, and emissions of waste.

[0003] Solvent extraction is a commonly used method for obtaining and separating nickel and cobalt from the liquid phase. The main problem with this method lies in the co-extraction of metallic impurities with nickel and cobalt. In currently used phosphoric acid extractants and extraction systems, metallic impurities are extracted before or at a similar extraction priority to nickel and cobalt. Therefore, impurities with low pH precipitates, such as iron and aluminum, need to be removed by precipitation, while impurities such as calcium, magnesium, manganese, and zinc are removed using multi-stage extraction. To achieve a shorter separation process for nickel and cobalt, it is necessary to change the metal extraction priority of the extraction system and improve the selectivity of nickel and cobalt. To this end, researchers are continuously developing extractants and extraction systems capable of selectively extracting nickel and cobalt from complex leachates.

[0004] Due to the excellent coordination properties of nitrogen atoms with nickel and cobalt, various nitrogen-containing extractants or ligands have been synthesized and studied, mainly including oximes and pyridine derivatives. However, oxime extractants are easily decomposed in the presence of organic acids, limiting their application range. Pyridine carboxylic acid ester extractants do not have this problem, and their synergistic extraction system with acidic extractants has been favored by researchers. However, this synergistic extraction system suffers from the problem of easy destruction of ester bonds during back-extraction and insufficient nickel-cobalt selectivity.

[0005] In summary, existing extraction systems for nickel-cobalt extraction and separation either require complex extraction and separation processes or have short lifespans, making it difficult to extract and separate nickel-cobalt from complex solution systems. Summary of the Invention

[0006] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes an amine-containing bidentate ligand, which, when combined with an extractant, yields an organic phase that can solve the technical problems of low extraction capacity, low selectivity and priority of nickel and cobalt, and short lifespan of the organic phase in traditional solvent extraction and separation of nickel and cobalt.

[0007] The present invention also provides a method for preparing the above-mentioned bidentate ligand.

[0008] This invention also provides applications of the aforementioned bidentate ligands.

[0009] According to an embodiment of a first aspect of the present invention, an amino-containing bidentate ligand is provided, said bidentate ligand having the structure shown in Formula I:

[0010]

[0011] Where R is C4~C 12 Alkyl groups.

[0012] The bidentate ligands according to embodiments of the present invention have at least the following beneficial effects:

[0013] This invention proposes a ligand with a [N,N] bidentate structure and a protonated amine group, which acts as both a hydrogen bond donor and acceptor. It can interact intermolecularly with acidic extractants that also act as hydrogen bond donors and acceptors, forming a hydrogen bond network. The resulting complex can participate in the inner-layer coordination of nickel and cobalt ions. In other words, the bidentate ligand provided by this invention, due to its structural design, can significantly improve the extraction and separation efficiency of nickel and cobalt.

[0014] Compared with ligands that simply have a [N,N] bidentate structure but lack a protonated amine group (i.e., the substituent is on the amine group, hereinafter referred to as conventional ligands), although conventional ligands also exhibit ion association mechanisms for metal extraction and the pH of the solution remains almost unchanged before and after extraction, they do not have the inductive effect of the protonated amine group or the characteristic of acting as a hydrogen bond donor. Therefore, conventional ligands do not have an extraction effect on nickel and cobalt (they only have the function of assisting coordination). However, the bidentate ligands provided by this invention, due to the presence of a protonated amine group, additionally possess the ability to coordinate with nickel and cobalt, and capture nickel and cobalt through ion association in the form of sulfate. Therefore, the bidentate ligands provided by this invention significantly improve the extraction rate and saturation capacity for nickel and cobalt.

[0015] Furthermore, whether the amino group in the bidentate ligand contains a proton significantly impacts the synergistic effect with the extractant. Traditional synergistic extraction systems composed of bidentate ligands and extractants exhibit strong anti-synergistic effects on metals other than nickel and cobalt, with low cobalt extraction rates and low nickel extraction saturation capacity. In contrast, the synergistic extraction system composed of bidentate ligands and extractants provided by this invention simultaneously ensures high extraction rates for both nickel and cobalt, significantly improving extraction saturation capacity. Moreover, the bidentate ligands provided by this invention have different affinities for nickel and cobalt, enabling further separation of nickel and cobalt through back-extraction. Therefore, the introduction of a proton on the amino group has a significant impact on the extraction behavior of nickel, cobalt, and other metallic impurities.

[0016] Furthermore, in the bidentate ligands provided by this invention, the long-chain alkyl group ensures both oil solubility and hydrophobicity, promoting the entry of nickel and cobalt from the aqueous phase into the organic phase and completing their separation from other metals, thus accelerating phase separation. If the side chain is not a long-chain alkyl group but contains hydrophilic groups such as hydroxyl groups, the hydrophobicity of the bidentate ligand will be significantly affected, thereby affecting its phase separation during extraction. If the side chain is not a long-chain alkyl group but an aryl or other heterocyclic group, the side chain will affect the charge distribution and conjugated structure on the main ring of the bidentate ligand provided by this invention, thereby affecting the extraction behavior of protonated amine groups and other related sites. In addition, the selection of the type of long-chain alkyl group also lays the foundation for the subsequent preparation method; that is, selecting a suitable side chain structure can significantly improve the yield and purity of the bidentate ligand during the preparation process and enhance its stability. In other words, the type and length of the side chain, to a certain extent, affect the practicality of the bidentate ligand in extraction and simultaneously simplify the preparation process.

[0017] In summary, the ligands provided by this invention exhibit good selectivity for both nickel and cobalt, while inhibiting the extraction of other impurity metal ions. They also have advantages such as stable extract structure, large saturation capacity, and clear phase separation.

[0018] According to some embodiments of the present invention, in the structure shown in Formula I, R is a C4 straight-chain alkyl, C6 straight-chain alkyl, C8 straight-chain alkyl, C... 12 Straight-chain alkyl, C8 branched alkyl and C 12 One of the branched alkyl groups.

[0019] According to some embodiments of the present invention, the C8 branched alkyl group includes ethylhexyl.

[0020] According to some embodiments of the present invention, C 12 Branched alkyl groups include 2-butyl-octyl.

[0021] According to some embodiments of the present invention, the bidentate ligand is a white solid. This is because the bidentate ligand has intramolecular hydrogen bonds. In contrast, conventional ligands appear as a yellow oily substance.

[0022] According to an embodiment of a second aspect of the present invention, a method for preparing the aforementioned amine-containing bidentate ligand is provided, the method comprising the following steps:

[0023] S1. React ethyl 2-pyridinecarboxylate (CAS: 2524-52-9) with a methyl ketone of the structural formula CH3COR via a nucleophilic substitution reaction to obtain the intermediate shown in Formula II;

[0024] S2. The intermediate product and hydrazine are reacted to synthesize Knorr pyrazole;

[0025]

[0026] Since the preparation method adopts all the technical solutions of the bidentate ligands in the above embodiments, it has at least all the beneficial effects brought about by the technical solutions in the above embodiments.

[0027] Furthermore, the preparation method provided by the present invention is simple and easy to implement, facilitating the large-scale industrial use of the ligand.

[0028] According to some embodiments of the present invention, in step S1, the temperature of the nucleophilic substitution reaction is 50–70°C.

[0029] According to some embodiments of the present invention, in step S1, the nucleophilic substitution reaction includes the following steps:

[0030] S1a. The methyl ketone is stirred and mixed with a tetrahydrofuran solution of sodium hydride and heated;

[0031] S1b. Add the tetrahydrofuran solution of the ethyl 2-pyridinecarboxylate (CAS: 2524-52-9) to the mixture obtained in step S1a and continue stirring to react.

[0032] According to some embodiments of the present invention, the methyl ketone includes methyl octyl ketone (CAS: 693-54-9).

[0033] According to some embodiments of the present invention, the molar ratio of the methyl ketone and the sodium hydride is 1:1 to 2. Specifically, it can be about 1:1.5, 1:1.6, or about 1:1.7.

[0034] According to some embodiments of the present invention, in the sodium hydride tetrahydrofuran solution, the mass-to-volume ratio of sodium hydride (based on the actual crude product mass used) to tetrahydrofuran is 50-100 mg: 1 mL. For example, it can be approximately 80 mg: 1 mL.

[0035] According to some embodiments of the present invention, in step S1a, the stirring and mixing time is 10 to 30 minutes. For example, it can be about 15 minutes, 20 minutes, or about 25 minutes. In actual industrial production, the mixing method and duration are not strictly limited, as long as sufficient mass transfer is achieved.

[0036] In step S1a, the mixing temperature is not strictly limited. In actual production, considering cost and safety factors, room temperature (about 25°C) can be used directly.

[0037] According to some embodiments of the present invention, in step S1a, the target temperature for heating is 50 to 70°C, specifically about 55°C, 60°C, or about 65°C.

[0038] According to some embodiments of the present invention, in step S1b, the concentration of the tetrahydrofuran solution of ethyl 2-pyridinecarboxylate is 1 to 1.5 mol / L. For example, it can be 1.2 to 1.3 mol / L.

[0039] According to some embodiments of the present invention, in step S1b, a tetrahydrofuran solution of ethyl 2-pyridinecarboxylate is added, and the time taken is ≤2 min.

[0040] According to some embodiments of the present invention, in step S1, the molar ratio of ethyl 2-pyridinecarboxylate to methyl ketone is 1:0.8 to 1.2. For example, it can be about 1:1.

[0041] According to some embodiments of the present invention, in step S1b, the temperature of the stirring reaction is the target heating temperature in step S1a. That is, it can actually be 50-70°C. More specifically, it can be about 55°C, 60°C, or about 65°C.

[0042] According to some embodiments of the present invention, in step S1b, the duration of the stirring reaction is 10 to 30 minutes. For example, it can be about 15 minutes, 20 minutes, or about 25 minutes.

[0043] According to some embodiments of the present invention, step S1 further includes, after step S1b, cooling the compound obtained in step S1b, adjusting the pH, and then purifying the intermediate product.

[0044] The temperature of the mixture obtained by cooling is -5 to 5°C, specifically approximately -2°C, 0°C, or approximately 2°C.

[0045] After pH adjustment, the resulting mixture has a pH range of 8–9. The pH adjuster used includes hydrochloric acid. The concentration of the hydrochloric acid used is 0.08–0.12 mol / L; specifically, it can be approximately 0.1 mol / L.

[0046] The purification of the intermediate product includes sequential ether extraction, washing the obtained organic phase with brine, dehydration of the obtained organic phase, and vacuum concentration.

[0047] The O / A ratio of the ether extraction is 1:3 to 5, for example, it can be about 1:4.

[0048] The ether extraction is performed 4 to 6 times, for example, 5 times.

[0049] The brine used for the brine washing is a saturated sodium chloride aqueous solution.

[0050] The O / A ratio of the brine washing is 1:0.8 to 1.2; for example, it can be approximately 1:1.

[0051] The resulting organic phase was dehydrated by drying with magnesium sulfate.

[0052] The vacuum concentration is performed at a vacuum level of 0.08–0.09 MPa.

[0053] The time between the end of step S1 and the start of step S2 is ≤10 minutes.

[0054] According to some embodiments of the present invention, in step S2, the Knorr pyrazole synthesis reaction is carried out in an ethanol solvent.

[0055] According to some embodiments of the present invention, in step S2, the molar ratio of the hydrazine hydrate and the intermediate product is 2 to 3:1; for example, it can be about 2.2:1, 2.5:1 or about 2.8:1.

[0056] According to some embodiments of the present invention, in step S2, the concentration of hydrazine hydrate in the ethanol solvent is 0.8 to 1 mol / L. Specifically, it can be about 0.85 mol / L, 0.9 mol / L, or about 0.95 mol / L.

[0057] According to some embodiments of the present invention, in step S2, the Knorr pyrazole synthesis reaction is a reflux reaction.

[0058] The duration of the reflux reaction is 80–100 minutes. For example, it can be approximately 90 minutes.

[0059] According to some embodiments of the present invention, step S2 further includes purifying the bidentate ligand after the Knorr pyrazole synthesis reaction.

[0060] The purification of the bidentate ligand includes sequential vacuum distillation, silica gel column chromatography, and solvent removal.

[0061] The vacuum degree of vacuum distillation is 0.05 to 0.1 MPa; for example, it can be about 0.07 MPa or about 0.08 MPa.

[0062] The temperature for vacuum distillation is 45–55°C; specifically, it can be about 50°C.

[0063] Furthermore, the silica gel column chromatography uses toluene as a purifying agent to remove impurities from the product, and ethyl acetate as an eluent to elute the product in the column.

[0064] The solvent removal method includes vacuum solvent removal. Specifically, the vacuum level is ≥0.09 MPa. For example, it can be approximately 0.1 MPa.

[0065] According to some embodiments of the present invention, the mechanism of the preparation method is as follows:

[0066]

[0067] According to an embodiment of a third aspect of the present invention, an organic phase is provided, the raw materials for preparing the organic phase including an extractant and the bidentate ligand described in the first aspect of the present invention.

[0068] Since the organic phase employs all the technical solutions of the bidentate ligands described in the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments. Specifically:

[0069] In the organic phase provided by this invention, the bidentate ligand acts as both a hydrogen bond donor and acceptor, exhibiting intermolecular interactions with commonly used extractants such as DNNSA, forming a hydrogen bond network. The resulting molecular associative compounds preempt the active hydrogen in the extractant, hindering the binding of impurity ions with the commonly used extractant, thereby achieving highly efficient and preferential extraction of nickel and cobalt. Furthermore, because the organic phase provided by this invention has different priorities for nickel and cobalt, the separation of nickel and cobalt can be achieved by changing the concentration of the extractant or the stripping agent. In other words, the organic phase provided by this invention is suitable for the separation and recovery of nickel and cobalt from complex compositions such as minerals or secondary resources.

[0070] The organic phase provided by this invention is easily separated from the aqueous phase, does not easily emulsify, and does not require saponification. The introduction of an extractant overcomes the drawbacks of the bidentate ligand's hydrophilicity and easy emulsification, without affecting the extraction efficiency of the organic phase for nickel and cobalt.

[0071] According to some embodiments of the present invention, the extractant includes at least one selected from dinonylnaphthalenesulfonic acid (DNNSA, CAS: 25322-17-2), bis(2-ethylhexyl)phosphonic acid (P204, CAS: 298-07-7), mono-2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (P507, CAS: 14802-03-0), bis(2,4,4-trimethylpentyl)phosphonic acid (Cyanex272, CAS: 83411-71-6), and neodecanoic acid (V10, CAS: 26896-20-8). Compared with other commonly used extractants, the above-mentioned acidic extractants are more likely to form hydrogen bond networks with the bidentate ligands, thereby making the synergistic effect between the extractant and the bidentate ligands more pronounced.

[0072] According to some embodiments of the present invention, the molar ratio of the extractant to the bidentate ligand in the organic phase is 0.25 to 4:1. Specifically, it can be about 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 1:1, 1.2:1, 1.5:1, 1.8:1, 2:1, 2.5:1, 3:1, or about 3.5:1.

[0073] According to some embodiments of the present invention, the raw materials for preparing the organic phase also include a diluent.

[0074] According to some embodiments of the present invention, the diluent includes at least one of toluene, sulfonated kerosene, and xylene.

[0075] According to some embodiments of the present invention, the concentration of the extractant in the organic phase is 0.01 to 0.1 mol / L. Specifically, it can be about 0.02 mol / L, 0.03 mol / L, 0.04 mol / L, 0.05 mol / L, 0.06 mol / L, 0.07 mol / L, 0.08 mol / L, or about 0.09 mol / L.

[0076] According to an embodiment of a fourth aspect of the present invention, a method for extracting and separating Ni / Co from a solution is provided, the method comprising extracting a mixed aqueous solution with an organic phase as described in an embodiment of a third aspect of the present invention; the aqueous solution contains ionic Ni and / or Co, as well as impurity ions; the impurity ions include Mn. 2+ Mg 2+ Al 3+ Ca 2+ Zn 2+ and Fe 3+ At least one of them.

[0077] Since the method employs all the technical solutions of the organic phase in the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions in the above embodiments. Specifically:

[0078] In this method, the organic phase is easily separated from the aqueous phase, is not easily emulsified, and requires no saponification. The organic phase exhibits different extraction priorities for impurity ions, nickel, and cobalt. Therefore, in actual production, the separation of nickel, cobalt, and impurity ions can be easily achieved by controlling the extraction or back-extraction conditions, thereby significantly reducing the difficulty of nickel / cobalt extraction and shortening the process flow. Regarding condition control, some principles are as follows: Under lower pH conditions (e.g., pH ≤ 2), the partition coefficient between nickel / cobalt and other impurity metal ions, as well as the extraction efficiency of nickel / cobalt, can be significantly improved.

[0079] According to some embodiments of the present invention, in the mixed aqueous solution,

[0080] If ionic nickel is included, then Ni is also included. 2+ Its concentration is 0.5 to 2 g / L; for example, it can be about 1.0 g / L or about 1.5 g / L.

[0081] If ionic cobalt is included, then Co is included. 2+ Its concentration is 0.3 to 1.0 g / L; for example, it can be about 0.5 g / L, 0.6 g / L, 0.7 g / L or about 0.8 g / L.

[0082] The concentration of a single impurity ion is ≤10 g / L; for example, it can be about 9 g / L, 8 g / L, 5 g / L, 3 g / L, 1 g / L, 0.7 g / L, 0.6 g / L, 0.5 g / L, 0.4 g / L, 0.3 g / L, 0.2 g / L or about 0.1 g / L.

[0083] Therefore, the method provided by the present invention is applicable to the extraction and separation of cobalt and nickel in mixed aqueous solutions with low cobalt and nickel content and high impurity content.

[0084] According to some embodiments of the present invention, the pH of the mixed aqueous solution is 0 to 3. Specifically, it can be about 0.5, 1, 1.5, 2, or about 2.5. If, in actual production, the pH of the directly obtained mixed aqueous solution is not within the above range, the pH needs to be adjusted, for example, by adding a certain amount of sodium hydroxide or calcium oxide.

[0085] According to some embodiments of the present invention, the mixed aqueous solution is an acid leaching solution of minerals or secondary resources.

[0086] According to some embodiments of the present invention, the secondary resources include at least one of decommissioned lithium-ion secondary batteries, decommissioned sodium-ion secondary batteries, decommissioned nickel-metal hydride batteries, cobalt slag from Fumei, and decommissioned nickel-containing catalysts. That is, virtually any decommissioned material containing nickel or cobalt is applicable.

[0087] According to some embodiments of the present invention, the method includes the following steps:

[0088] A1. Extract the mixed aqueous solution with the organic phase to obtain the raffinate phase and the supported organic phase; the amount of extractant in the organic phase is greater than or equal to the theoretical amount of extractant required for Ni and Co in the mixed aqueous solution;

[0089] A2. Back-extract the supported organic phase with sulfuric acid aqueous solution A to obtain an aqueous phase rich in impurity ions and an organic phase rich in nickel and cobalt; the hydrogen ion concentration in the sulfuric acid aqueous solution A is ≤0.2 mol / L;

[0090] A3. Back-extract the nickel-cobalt-rich organic phase with sulfuric acid aqueous solution B to obtain a cobalt-rich aqueous phase and a nickel-rich organic phase; the hydrogen ion concentration in the sulfuric acid aqueous solution B is greater than 0.2 mol / L and not less than 2 mol / L;

[0091] A4. Back-extract the nickel-rich organic phase with sulfuric acid aqueous solution C to obtain a nickel-rich aqueous phase and a blank organic phase; the hydrogen ion concentration in the sulfuric acid aqueous solution C is 4-6 mol / L.

[0092] According to some embodiments of the present invention, in step A1, the pH of the raffinate phase is 0.3 to 3.0. Specifically, it can be about 0.5, 1.0, 1.5, 2.0, or about 2.5. If the pH of the raffinate phase changes, it needs to be adjusted, for example, using sulfuric acid or sodium hydroxide as a pH adjuster. Typically, this range can be adjusted by changing the initial pH of the aqueous solution (the mixed aqueous solution).

[0093] According to some embodiments of the present invention, in step A1, the O / A ratio of the extraction is 1:4 to 4:1. Specifically, it can be approximately 1:2, 1:1, 2:1, or approximately 1:3. In actual production, the actual amount of extractant used in the extraction can be further adjusted by regulating the concentration and other composition of the extractant in the organic phase.

[0094] According to some embodiments of the present invention, in step A1, the extraction time is 5 to 15 minutes; specifically, it can be about 10 minutes. This time is the time for mixing the organic phase and the aqueous phase. The mixing method includes at least one of shaking and stirring. When the mixing method is stirring, the stirring speed is 500 to 700 rpm, specifically, it can be about 600 rpm.

[0095] According to some embodiments of the present invention, in step A1, the extraction temperature is 10–50°C. Ambient temperature is usually sufficient, and no additional temperature adjustment is required. For example, it can be room temperature in the conventional sense, i.e., about 25°C; or it can be about 15°C, 20°C, 30°C, 35°C, 40°C, or about 45°C.

[0096] According to some embodiments of the present invention, in step A2, the hydrogen ion concentration in the sulfuric acid aqueous solution A is between 0.1 and 0.2 mol / L.

[0097] According to some embodiments of the present invention, in step A2, the O / A ratio of the back-extraction is 1:1 to 5; for example, it can be 1:2.

[0098] According to some embodiments of the present invention, in step A2, the back-extraction time is 5 to 15 minutes; specifically, it can be about 10 minutes. Within the above time range, the organic phase and the aqueous phase need to be mixed, and the mixing method includes at least one of shaking and stirring.

[0099] According to some embodiments of the present invention, in step A2, the temperature of the back-extraction is 20–30°C. For example, it can be approximately 25°C.

[0100] In step A2, the resulting aqueous phase rich in impurity ions may also contain cobalt. Specifically, the proportion of cobalt is determined by the O / A ratio, extraction acidity, time, and composition of the supported organic phase during extraction in step A2. In other words, the organic phase has a slightly stronger affinity for cobalt ions than impurity ions, such as zinc ions, but far less affinity than nickel ions. Therefore, for an organic phase containing nickel, cobalt, and impurity ions, if the extraction acidity is slightly high, some cobalt from the organic phase may be carried into the aqueous phase rich in impurity ions. Since the organic phase has a lower extraction priority for impurity ions than nickel and cobalt, controlling the amount of organic phase or the acid concentration during extraction in step A2 can reduce the impurity ions carried in the organic phase, thus eliminating the need for zinc washing; or it can reduce the amount of cobalt lost during extraction.

[0101] According to some embodiments of the present invention, in step A3, the O / A ratio of the back-extraction is 1:1 to 5; for example, it can be 1:2.

[0102] According to some embodiments of the present invention, in step A3, the back-extraction time is 5 to 15 minutes; specifically, it can be about 10 minutes. Within the above time range, the organic phase and the aqueous phase need to be mixed, and the mixing method includes at least one of shaking and stirring.

[0103] According to some embodiments of the present invention, in step A3, the temperature of the back-extraction is 20–30°C. For example, it can be approximately 25°C.

[0104] According to some embodiments of the present invention, in step A4, the O / A ratio of the back-extraction is 1:1 to 5; for example, it can be 1:2.

[0105] According to some embodiments of the present invention, in step A4, the back-extraction time is 5 to 15 minutes; specifically, it can be about 10 minutes. Within the above time range, the organic phase and the aqueous phase need to be mixed, and the mixing method includes at least one of shaking and stirring.

[0106] According to some embodiments of the present invention, in step A4, the temperature of the back-extraction is 20–30°C. For example, it can be approximately 25°C.

[0107] It should be noted that the conditions for back-extraction in steps A2 to A4 can be the same or different, except for the acid solution used.

[0108] According to some embodiments of the present invention, the method further includes washing the blank organic phase after step A4 to obtain a regenerated organic phase. In actual production, the regenerated organic phase can be reused for extraction in step A1, thereby realizing the recycling of raw materials and saving costs.

[0109] According to some embodiments of the present invention, the method includes the following steps:

[0110] B1. Extract the mixed aqueous solution with the organic phase to obtain raffinate phase A and nickel-supported organic phase; the amount of extractant in the organic phase is less than or equal to the theoretical amount of extractant required for Ni in the mixed aqueous solution;

[0111] B2. Extract the raffinate phase A with the organic phase to obtain raffinate phase B and cobalt-supported organic phase.

[0112] The mechanisms of steps B1 to B2 are as follows:

[0113] In the raffinate phase A, the main components are cobalt and impurity ions; that is, step B1 achieves the separation of nickel and other components.

[0114] In the raffinate phase B, the main component is impurity ions; that is, step B2 achieves the separation of cobalt and impurity ions.

[0115] The methods in steps B1 and B2, through two simple extraction stages, efficiently extract nickel and cobalt from mixed aqueous solutions while further separating them to obtain high-purity nickel-based and cobalt-based aqueous solutions. Compared with traditional extraction, this significantly simplifies the nickel / cobalt separation process and reduces extraction costs. During the process, by adjusting the amount of organic phase in step B1, the extraction selectivity of step B1 is high; the loaded organic phase contains only nickel, and direct back-extraction yields a high-purity nickel-based aqueous solution. In step B2, due to the presence of some residual nickel ions in the raffinate phase A, the cobalt-loaded organic phase contains a small amount of nickel and most of the cobalt ions. By adjusting the concentration of the acid used for back-extraction, only cobalt can be back-extracted into the aqueous phase to obtain a cobalt-based aqueous solution. The nickel-poor loaded organic phase can be washed and then directly entered into the extraction operation, or it can be mixed with the nickel-loaded organic phase obtained in step B1 and then back-extracted.

[0116] According to some embodiments of the present invention, in step B1, the extraction time is 5 to 15 minutes; for example, it can be about 10 minutes.

[0117] In step B1, other conditions related to extraction can be referenced from the condition selection range in step A1. The specific selection point values ​​can be the same as or different from those in step A1.

[0118] According to some embodiments of the present invention, step B1 further includes back-extracting the nickel-supported organic phase to obtain a nickel-based aqueous solution and a blank organic phase; and washing the blank organic phase to obtain a regenerated organic phase. Wherein,

[0119] The back-extraction of the nickel-supported organic phase uses the sulfuric acid aqueous solution C as the back-extraction agent. For specific back-extraction conditions, please refer to the back-extraction condition range in step A3. The specific selection point value can be the same as or different from step A3.

[0120] The regenerated organic phase can be reused in step B1, or as the organic phase in step B2. This saves on reagent costs for the method.

[0121] According to some embodiments of the present invention, in step B2, the amount of extractant used in the organic phase is greater than or equal to the theoretical amount of extractant required for Ni and Co in the raffinate phase A.

[0122] In step B2, the extraction conditions, such as extraction temperature and duration, except for the amount of extractant, are determined with reference to the extraction conditions in step A1. The specific point values ​​selected can be the same as or different from those in step A1.

[0123] According to some embodiments of the present invention, step B2 further includes back-extracting the cobalt-supported organic phase to obtain a cobalt-based aqueous solution and a nickel-poor supported organic phase; the nickel-poor supported organic phase is returned to step B1, mixed with the nickel-supported organic phase, and subjected to uniform back-extraction.

[0124] In step B2, the reason why a small amount of nickel remains in the organic phase after cobalt back-extraction is that, in order to improve the purity of the nickel-loaded organic phase, the amount of organic phase used in step B1 is slightly lower than its theoretical requirement. Therefore, the raffinate phase A still contains a small amount of nickel, which will enter the organic phase during extraction in step B2.

[0125] The back-extraction of the cobalt-supported organic phase uses the sulfuric acid aqueous solution B as the back-extraction agent; for specific back-extraction conditions, please refer to the back-extraction condition range in step A2, and the specific selection point value can be the same as or different from that in step A2.

[0126] According to some embodiments of the present invention, the method includes the following steps:

[0127] C1. Extract the mixed aqueous solution with the organic phase to obtain an impurity raffinate phase and a nickel-cobalt supported organic phase; the amount of extractant in the organic phase is greater than the theoretical amount of extractant required for Ni in the mixed aqueous solution, and less than the theoretical amount of extractant required for Ni and Co in the mixed aqueous solution;

[0128] C2. The nickel-cobalt supported organic phase is back-extracted with sulfuric acid aqueous solution B to obtain a cobalt-containing aqueous solution and a nickel-containing organic phase; the hydrogen ion concentration in the sulfuric acid aqueous solution B is greater than 0.2 mol / L and not less than 2 mol / L;

[0129] C3. Back-extract the nickel-containing organic phase with sulfuric acid aqueous solution C to obtain a nickel-containing aqueous solution and a blank organic phase; the hydrogen ion concentration in the sulfuric acid aqueous solution C is 4-6 mol / L.

[0130] According to some embodiments of the present invention, except for the limiting conditions, the extraction in step C1 refers to the range of extraction conditions selected in step A1; the specific selected point values ​​may be the same as or different from those in step A1.

[0131] According to some embodiments of the present invention, except for the limiting conditions, the back-extraction in steps C2 and C3 refers to the selection range of back-extraction conditions in step A2; the specific selected point values ​​may be the same as or different from those in step A2.

[0132] According to some embodiments of the present invention, step C3 further includes washing the blank organic phase to obtain a regenerated organic phase. The obtained regenerated organic phase can be recycled to step C1, completely or partially replacing the organic phase therein. This saves reagent costs.

[0133] Unless otherwise specified, the theoretical amount of extractant in the method is based on its saturated capacity, more precisely, on the saturated capacity of a specific organic phase; the amount of extractant used (actual amount) is related to the O / A ratio of the extraction process and the composition of the organic phase.

[0134] Unless otherwise specified, all extraction processes described in this method are single-stage extractions. This significantly reduces the complexity of the process.

[0135] Unless otherwise specified, the washing method refers to washing with deionized water. Therefore, the regeneration method for the organic phase including the bidentate ligand is simple and easy to operate, further reducing the difficulty of nickel / cobalt extraction. The deionized water washing has an O / A ratio of 1:0.8 to 1.2, specifically approximately 1:1; the deionized water washing time is 3 to 8 minutes, specifically approximately 5 minutes.

[0136] According to an embodiment of the fifth aspect of the present invention, an application is provided of a bidentate ligand as described in the first aspect of the present invention, or an organic phase as described in the third aspect of the present invention, or a method as described in any of the fifth to seventh aspects of the present invention, in nickel ore mining and waste resource recycling.

[0137] Since the application employs all the technical solutions of the bidentate ligands, organic phases, or methods described in the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments. That is,

[0138] In the nickel ore mining and waste resource recycling processes, the operation process can be significantly shortened, and the separation efficiency between nickel and cobalt, as well as the separation efficiency between nickel, cobalt and impurity ions, can be improved.

[0139] According to some embodiments of the present invention, the waste resources used in the waste resource recycling include at least one of decommissioned lithium-ion secondary batteries, decommissioned sodium-ion secondary batteries, decommissioned nickel-metal hydride batteries, Fumei cobalt slag, and decommissioned nickel-containing catalysts. That is, practically any decommissioned material containing nickel or cobalt is applicable.

[0140] Unless otherwise specified, the term "about" in this invention actually means that the error is allowed to be within ±2%, for example, about 100 is actually 100 ± 2% × 100.

[0141] Unless otherwise specified, "between" in this invention includes the number itself, for example, "between 2 and 3" includes the endpoint values ​​2 and 3.

[0142] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0143] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0144] Figure 1This is a schematic flowchart of a method for extracting and separating Ni / Co from solution, provided in an application example of the present invention.

[0145] Figure 2 This is a schematic flowchart of a method for extracting and separating Ni / Co from solution, provided in an application example of the present invention.

[0146] Figure 3 This is a schematic flowchart of a method for extracting and separating Ni / Co from solution, provided in an application example of the present invention.

[0147] Figure 4 This is the 1H NMR spectrum of the bidentate ligand obtained in Example 1 of this invention;

[0148] Figure 5 This is the carbon NMR spectrum of the bidentate ligand obtained in Example 1 of this invention;

[0149] Figure 6 This is the infrared spectrum of the bidentate ligand obtained in Example 1 of the present invention;

[0150] Figure 7 This is a thermogravimetric diagram of the bidentate ligand obtained in Example 1 of the present invention;

[0151] Figure 8 This is a schematic diagram illustrating the synergistic effect between bidentate ligands and extractants in the organic phase, provided in an application example of the present invention. Detailed Implementation

[0152] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0153] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0154] Unless otherwise specified, in the specific implementation method, the distribution ratio D, separation coefficient β, and extraction rate E are... x (%), back-extraction rate E s (%) are calculated according to equations (1) to (5) respectively:

[0155] D = C MOrg / C MAq (1);

[0156] β Ni / M =D Ni / D M (2);

[0157] β Co / M =D Co / D M (3);

[0158] E x =(C M0 -C MA ) / C M0 (4);

[0159] E s =C Ms V s / C MOrg V Org (5);

[0160] In equation (1), C MOrg C MAq Represent the concentrations (mol / L) of metal ions M in the supported organic phase and the raffinate phase, respectively; β in equations (2) and (3) Ni / M ,β Co / M D represents the separation coefficients of Ni, Co, and impurity M, respectively; Ni D Co D M Represent the distribution ratios of Ni, Co, and impurity M, respectively; in equation (4), C M0 , represents the initial concentration (mol / L) of metal ion M in the aqueous phase to be extracted; C in equation (5) Ms V represents the metal ion concentration (mol / L) of the back-extraction solution. s V Org These represent the volumes of the back-extraction solution and the supported organic phase, respectively.

[0161] Example 1

[0162] This example demonstrates the preparation of a bidentate ligand containing a protonated amine group. The specific steps are as follows:

[0163] S1. Nucleophilic substitution reaction:

[0164] S1a. 2-Decanone (methyl octyl ketone, CAS: 693-54-9) was mixed with a tetrahydrofuran solution of sodium hydride at room temperature (approximately 25°C) for 20 min, and then heated to 60°C; wherein,

[0165] The molar ratio of 2-decanone to sodium hydride (based on pure NaH) is 1:1.6;

[0166] The mass-to-volume ratio of sodium hydride (based on 60 wt% actual usage) to tetrahydrofuran is 80 mg / mL.

[0167] S1b. A tetrahydrofuran solution of ethyl 2-pyridinecarboxylate (CAS: 2524-52-9) is slowly added dropwise (total time approximately 2 min) to the mixture obtained in step S1a, and stirred at 60°C for 20 min; wherein,

[0168] The concentration of tetrahydrofuran solution of ethyl 2-pyridinecarboxylate (CAS: 2524-52-9) is 1.25 mol / L;

[0169] The molar ratio of ethyl 2-pyridinecarboxylate to 2-decone used is 1:1.

[0170] S1c. Cool the mixture obtained in step S1b to 0°C and adjust its pH to 8-9 (any range within this range is acceptable) with dilute hydrochloric acid (0.1 mol / L);

[0171] S1d. The mixture obtained in step S1c is extracted with diethyl ether, and the resulting organic phase is washed with brine, dried over anhydrous magnesium sulfate, and concentrated under vacuum (0.09 MPa) to obtain the intermediate product 1-(pyridin-2-yl)heptane-1,3-dione; wherein,

[0172] The O / A ratio used for ether extraction was 1:4, and the extraction was performed 5 times.

[0173] The brine used for washing is a saturated sodium chloride solution, and the O / A ratio for brine washing is 1:1.

[0174] S2. Within 10 minutes of the end of step S1d, the intermediate product 1-(pyridin-2-yl)heptane-1,3-dione and hydrazine hydrate are refluxed in a mixture of ethanol for 90 minutes; wherein,

[0175] The molar ratio of hydrazine hydrate to the intermediate product is 2.2:1;

[0176] The concentration of hydrazine hydrate in ethanol is 0.92 mol / L.

[0177] The solvent was removed by vacuum distillation (0.08 MPa, 50°C) of the mixture obtained from the reflux reaction. Then, impurities were removed by silica gel column chromatography, in which toluene was used as the impurity remover and ethyl acetate was used as the eluent to elute the product in the column. Finally, the solvent was removed by high vacuum (0.1 MPa) to obtain a white powder of bidentate ligand.

[0178] Example 2

[0179] This example prepares a bidentate ligand containing a protonated amine group, where R is a C4 straight-chain alkyl group. The specific steps differ from those in Example 1 in that:

[0180] Replace 2-decanoic acid in step S1 with an equal amount of 2-hexanone (CAS: 591-78-6).

[0181] Example 3

[0182] This example prepares a bidentate ligand containing a protonated amine group, where R is C 12 The difference between the linear alkyl group and Example 1 lies in the specific steps:

[0183] Replace the 2-decanoic acid in step S1 with an equal amount of 2-tetradecanoic acid (methyl dodecyl ketone, CAS: 2345-27-9).

[0184] Example 4

[0185] This example prepares a bidentate ligand containing a protonated amine group, where R is a branched C. 12 The difference between the alkyl group and the specific steps in Example 1 is as follows:

[0186] Replace the 2-decanoic acid in step S1 with an equal amount of 3-butyldecane-2-one (methylbutyldecyl one, Pubchem CID 54205874).

[0187] Test Example 1

[0188] This example tested the infrared and nuclear magnetic resonance (NMR) results of the bidentate ligands obtained in Examples 1-4 to prove that the present invention indeed synthesized the corresponding bidentate ligands. Thermogravimetric analysis (TGA) was then performed on them in air to test the thermal stability of the ligands under industrial conditions. The 1H NMR results showed a clear -NH (i.e., protonated amine) peak, indicating that in the preparation method provided by the present invention, the alkyl chain is indeed not directly connected to the protonated amine group. Furthermore, the combined 1H and 1C NMR spectra showed that the number of H and C atoms was exactly the same as that of the bidentate ligands designed in the present invention. Correspondingly, the infrared spectrum also significantly corroborated the structure of the bidentate ligands. Specifically, the NMR results of Example 1 are as follows: Figures 4-5 As shown, the infrared results are as follows Figure 6 As shown in the figure. Furthermore, thermogravimetric analysis (TGA) results show that the bidentate ligand provided by this invention begins to lose weight at 160°C, and the weight loss is rapid within the range of 160–350°C. This indicates that the bidentate ligand provided by this invention can be used at temperatures below 160°C. The thermogravimetric results of Example 1 are shown in the figure. Figure 7 As shown.

[0189] Furthermore, the NMR results for Example 2 are as follows: 1H NMR (500MHz, DMSO-d6) δ12.54(s,1H),8.49(d,J=4.7Hz,1H),7.94–7.88(m,1H),7.81(t,J=7.6Hz,1H),7.33(t ,J=6.4Hz,1H),6.62(s,1H),2.55(t,J=7.6Hz,2H),1.59(p,J=7.2Hz,2H),1.31(m,2H),1.03(t,J=6.7Hz,3H).

[0190] The NMR results for Example 3 are as follows: 1 H NMR (500MHz, DMSO-d6) δ12.61(s,1H),8.51(d,J=4.8Hz,1H),7.87–7.83(m,1H),7.76(t,J=7.6Hz,1H),7.24(t,J= 6.4Hz,1H),6.56(s,1H),2.57(t,J=7.7Hz,2H),1.62(p,J=7.3Hz,2H),1.25–1.17(m,18H),0.83(t,J=6.6Hz,3H).

[0191] The NMR results for Example 4 are as follows: 1 H NMR (500MHz, DMSO-d6) δ12.65(s,1H),8.52(d,J=4.9Hz,1H),7.88–7.83(m,1H),7.79(t,J=7.7Hz,1H),7.26(t,J=6.5H z,1H),6.59(s,1H),2.71(m,1H),1.55-1.51(m,4H),1.31–1.18(m,14H),0.83(t,J=6.7Hz,3H),0.74(t,J=6.3Hz,3H).

[0192] The above NMR results further demonstrate that, like in Example 1, Examples 2-4 yielded the expected target product.

[0193] Application Example 1

[0194] This example provides a set of organic phases, the specific composition of which is shown in Table 1:

[0195] Table 2 Composition of the organic phase in Application Example 1

[0196]

[0197]

[0198] Application Example 2

[0199] This example uses the C8-1, NH-C8-1, L1, and L2 groups from Application Example 1 to extract a mixed aqueous solution, and calculates the extraction rates of these four organic compounds relative to nickel, cobalt, and impurity metal ions. Specifically:

[0200] The main component of the mixed aqueous solution is Ni 2+ 1.208 g / L, Fe 3+ 0.622g / L, Al 3+ 0.078 g / L, Ca 2+ 0.426g / L, Co 2+ 0.537g / L, Zn 2+ 0.345 g / L, Mg 2+ 4.086 g / L, pH of the solution is 2.15; it is a pH-adjusted sulfuric acid leaching solution of laterite nickel ore.

[0201] The extraction site was a single-stage extraction with an O / A ratio of 1:1 and a temperature of 25℃. The mixing time for L1 and C8-1 group was 30 min, and the mixing time for L2 and NH-C8-1 group was 10 min. The mixing method was magnetic stirring at a speed of 600 rpm.

[0202] The test results are shown in Table 2.

[0203] Table 2 shows the extraction rates of organic compounds for different metal ions in Application Example 2.

[0204]

[0205]

[0206] The results above indicate significant differences between groups L1 and L2, both within themselves and within their synergistic extraction systems. Group L1 itself did not exhibit high extraction rates or selectivity for any metal in the solution. In the synergistic extraction system C8-1, L1 showed good selectivity and extraction performance for nickel, slightly improved extraction performance for cobalt, and exhibited antagonistic effects on other metals. In contrast, L2 itself showed high extraction rates for nickel, cobalt, iron, and zinc. This is due to its protonated amine group. When introduced into the synergistic extraction system NH-C8-1, L2 showed high selectivity for nickel and cobalt, slight co-extraction of zinc, and low extraction rates for other metals. The common feature of the ligands in L1 and L2 is that their extraction mechanism is ion association, with almost no change in the pH of the solution before and after extraction. However, L2, due to its stronger association energy with metal salt ions via its protonated amino group, exhibits certain extraction performance and specific extraction of nickel, cobalt, and iron. When introduced into an acidic extractant (DNNSA) extraction system, the extraction system exhibits a cation exchange mechanism, replenishing the protons lacking in L1, thus enabling the system to possess extraction performance and showing a certain selectivity for nickel and cobalt in the synergistic system. The interaction between L2 and DNNSA inhibits the co-extraction of iron and zinc, allowing nickel and cobalt to be separated from the multi-metal mixed solution, exhibiting an extraction capacity far superior to that of the L1 system. This demonstrates that the presence of the protonated amino group in the bidentate ligand provided by this invention significantly affects the extraction behavior of metal ions in mixed solutions, and also influences the extraction saturation capacity and selectivity of the organic phase.

[0207] Application Example 3

[0208] In this example, four different organic groups obtained from Application Example 1 were used to perform single-stage extraction on lateritic nickel ore sulfuric acid leaching solution (same as Application Example 2) to verify the extraction effect of the R-group (branched chain) type in the bidentate ligand on metal ions in the lateritic nickel ore sulfuric acid leaching solution. The extraction conditions were the same as in Application Example 2. The results are shown in Table 3.

[0209] Table 3 lists the properties of organic phases with different branched ligands.

[0210]

[0211]

[0212] The results showed that the growth of alkyl chains or the presence of branches (C8 and above) increased the steric hindrance of bidentate ligands, hindering metal entry into the coordination layer and reducing the extraction rate. In organic phases containing short-chain bidentate ligands (NH-C4), the extraction rates of nickel and cobalt decreased because impurity metals occupied part of the coordination sites. In organic phases containing branched bidentate ligands, the greater steric hindrance affected the interaction between the bidentate ligands and the extractant, leading to a decrease in the extraction rates of metals with stronger affinity for the bidentate ligands, while the extraction rate of impurities increased to some extent. However, in the organic phase of this experiment, nickel and cobalt extraction still dominated. Therefore, the design of the bidentate ligand structure can adjust its steric hindrance and alkyl chain structure, while also affecting the interaction between the bidentate ligands and the extractant, thereby changing the inhibition of impurities in organic phases and the extraction behavior of nickel and cobalt.

[0213] Application Example 4

[0214] This example uses the organic-to-sulfuric acid leaching solutions of lateritic nickel ore (numbered L2, HA, and NH-C8-1) obtained in Application Example 1 (the same mixed aqueous solution as in Application Example 2) for single-stage extraction (extraction conditions as in Application Example 2) to verify the effect of different organic-to-sulfuric acid leaching solutions on the extraction behavior of metal ions. The extraction rates of nickel, cobalt, and impurity metals, as well as the distribution ratios and distribution coefficients of nickel, cobalt, and other impurity ions, were calculated.

[0215] In this example, the extraction rates of each metal ion are shown in Table 4, and the partition ratios and separation coefficients are shown in Table 5.

[0216] Table 4 shows the extraction rates of different organic phases relative to metal ions in Application Example 4.

[0217]

[0218] Table 5 shows the separation coefficients and distribution ratios among nickel, cobalt, and other metals in Application Example 4.

[0219]

[0220]

[0221] Based on the above results, it can be seen that using commercial DNNSA extractant (HA) alone to extract nickel and cobalt exhibits poor selectivity. While it shows some extraction performance for all metals in the solution, the priority order is Al > Fe > Zn > Ca > Co > Ni > Mg. While using bidentate ligands alone (L2 group) to extract nickel and cobalt achieves high extraction rates, the co-extraction of iron and zinc prevents the separation of nickel and cobalt from impurities. Furthermore, the extraction process suffers from difficulties in phase separation and the formation of a third phase. When using a mixed system (NH-C8-1) to extract nickel, the extraction rate approaches 100%, and the extraction rate of cobalt reaches over 85%. The addition of commercial DNNSA successfully suppresses iron co-extraction, and the extraction rates of Fe, Al, Ca, and Mg impurity metals are below 2%. Slight zinc co-extraction exists, improving the problems of oil-water phase separation and third phase formation. This demonstrates that the interaction between the extractant and the bidentate ligand in the organic phase provided by this invention successfully suppresses the extraction of impurity metals, achieving the separation of nickel and cobalt from other impurity metals, and exhibiting rapid reaction kinetics. In the organic phase, the mechanism of synergistic effect between the extractant and the bidentate ligand is as follows: Figure 8 As shown.

[0222] The results also show that Ni and Co have very high separation coefficients from other metallic impurities (except zinc), and their separation coefficients for zinc are also above 30. Therefore, the organic phase provided by this invention can separate nickel and cobalt from other metals through single-stage extraction, and the amine-containing bidentate ligands are more easily applied to industrial extraction after being introduced into the extractant.

[0223] Application Example 5

[0224] In this example, the organic phase NH-C8-1 obtained in Application Example 1 was used to perform single-stage extraction on the sulfuric acid leaching solution of lateritic nickel ore (the same mixed aqueous solution as in Application Example 2), verifying the effect of the O / A ratio on the extraction efficiency. The remaining extraction conditions were the same as in Application Example 2. The relationship between the extraction efficiency and the O / A ratio is shown in Table 6.

[0225] Table 6. Effect of O / A ratio on extraction efficiency

[0226]

[0227]

[0228] The results showed that the extraction rates of all metal ions decreased with decreasing O / A ratio, with a sharp drop in the extraction rates of cobalt, zinc, and iron. The extraction rates of other impurity metals remained at low levels. While the extraction rate of nickel decreased, its organic phase loading increased. This phenomenon is attributed to the following: at high O / A ratios, after the organic phase is fully loaded with nickel, there are still free extractant-ligand associated molecules that coordinate with cobalt, zinc, and iron (excess extractant), resulting in co-extraction of zinc and iron. This also reflects the priority order of metal extraction in the system as Ni > Co > Zn > Fe. At low O / A ratios, the excess nickel ions in the aqueous phase saturate the organic phase, preventing other metals from entering the coordination phase, thus causing a sharp decrease in the extraction rates of cobalt, zinc, and iron. Adjusting the O / A ratio appropriately allows for better separation of nickel and cobalt from impurities. Considering the separation coefficients of nickel, cobalt, and impurity metals, as well as their extraction rates, the system achieves the best separation effect for each metal when the O / A ratio is 1:1. The extraction rate for nickel is close to 100%, for cobalt it exceeds 85%, for zinc it is around 20%, and the extraction rates for other impurity metals are all at relatively low levels. A single-stage extraction is sufficient to achieve preliminary separation of nickel, cobalt, and other metallic impurities. However, this ratio is affected by the composition of the aqueous solution and the organic phase. If these conditions change, the O / A ratio may also change.

[0229] Application Example 6

[0230] This example corresponds to the back-extraction of the supported organic phase obtained from the NH-C8-1 group in Case 4, verifying the effect of the acidity of the sulfuric acid solution used for back-extraction on the back-extraction efficiency. Specifically:

[0231] The O / A ratio for back-extraction was 1:1, the mixing time was 10 min, the stirring speed was 600 rpm, and the temperature was 25℃.

[0232] The acidity (hydrogen ion concentration) of the sulfuric acid solution used for back-extraction and its corresponding back-extraction effect are shown in Table 7.

[0233] Table 7. Effect of Acidity of Aqueous Phase Used for Back-extraction on Back-extraction Efficiency

[0234]

[0235] The results showed that under low acidity, zinc co-extracted from the organic phase could be successfully separated from nickel and cobalt and returned to the aqueous phase. With increasing acidity, the back-extraction rate of cobalt significantly increased, while the back-extraction rate of nickel remained low, especially at a hydrogen ion concentration of 2 mol / L, where the cobalt back-extraction rate approached 100%, while the nickel back-extraction rate was below 5%. Therefore, the back-extraction operation under these acidity conditions can achieve the separation of nickel and cobalt. Further increasing the acidity to a hydrogen ion concentration of 4 mol / L, cobalt, zinc, and nickel in the supported organic phase were all back-extracted into the aqueous phase.

[0236] Based on the above results, in the organic phase extraction process provided by this invention, the metals co-extracted in the supported organic phase can be separated by controlling the back-extraction acidity: low acidity removes impurity metals, higher acidity separates cobalt and nickel, and high acidity back-extracts nickel, achieving the separation and purification of the target metals without any other steps. In other words, Figure 1 The method shown is feasible and highly efficient.

[0237] Application Example 7

[0238] This example uses the organic phases NH-C8-2, NH-C8-3, and NH-C8-4 obtained in Application Example 1 to verify the effect of the extractant and its dosage in the organic phase on the extraction behavior of the sulfuric acid leaching solution of lateritic nickel ore (with the same composition as the mixed aqueous solution used in Application Example 2). The specific extraction conditions are the same as in Application Example 1, and the results are shown in Table 8.

[0239] Table 8 Effect of extractant dosage on extraction behavior

[0240]

[0241] The results showed that with increasing extractant dosage, the extraction rates of the organic phase for Ni, Co, and Zn significantly increased, while the extraction rates for other impurities remained at a low level. At low extractant dosages, the bidentate ligands provided in this invention exhibited a strong affinity for nickel, resulting in a high nickel extraction rate (>85%). Furthermore, the organic phase was nearly saturated, thus extracting almost no impurities. According to the priority order of ligand affinity for metals, cobalt was second only to nickel.

[0242] therefore, Figure 2 The illustrated method is feasible, involving nickel-loaded organic phase co-extraction, washing, and then extraction of the cobalt-containing raffinate phase A. With an appropriate amount of organic phase, the nickel extraction rate approaches 100%, and the cobalt extraction rate is around 60%, while the co-extraction of impurity metals is minimal. Furthermore, Figure 3 The method shown is also feasible; that is, by adjusting the amount of organic phase (or the amount of extractant), co-extraction of nickel and cobalt can be achieved to obtain a nickel-cobalt-loaded organic phase. Then, in conjunction with Application Example 6, the separation of nickel and cobalt in the nickel-cobalt-loaded organic phase is achieved by controlling the acidity of the back-extraction aqueous phase, and the cobalt-containing impurity raffinate is returned to the aqueous solution to be mixed. As provided in Application Example 6, such as... Figure 1 In the process, an excess of extractant is required. At this time, the extraction rates of nickel and cobalt are close to 100%, while some zinc is co-extracted (extraction rate of about 40%). Through three-stage back-extraction of low acid, higher acid, and high acid, impurity-rich aqueous phase, cobalt-rich aqueous phase, and nickel-rich aqueous phase can be obtained respectively.

[0243] Figures 1-3In all three pathways shown, the organic phase is recycled after washing and regeneration, but the processes differ significantly. Figure 1 The process consists of single-stage extraction, three-stage back-extraction, and one-stage regeneration. It has high extraction efficiency, short process, and simple operation. It also produces zinc as a byproduct and has low operating costs. However, the large amount of extractant used leads to high raw material costs. Figure 2 The path shown consists of two extraction stages, two back-extraction stages, and two regeneration stages. It uses a small amount of extractant, has low raw material costs, and has a higher organic phase recycling rate in the process. However, the two extraction stages make the operation more complex, the process longer, and the equipment cost higher. Figure 3 The illustrated path consists of a single-stage extraction, a two-stage back-extraction, and a single-stage regeneration operation. It uses an appropriate amount of extractant, has low raw material costs, and extracts only the target metals—nickel and cobalt—under the specified operating conditions, resulting in higher extraction efficiency, a shorter process, and simpler operation. However, the amount of extractant needs to be calculated and designed based on the composition of the extractant solution. Each of the three paths has its own advantages and disadvantages, but all are easily applicable in industrial production.

[0244] Application Example 8

[0245] This example verifies the effect of the molar ratio of bidentate ligands and extractant in the organic phase on the extraction behavior of sulfuric acid leachate (mixed aqueous solution) from retired ternary lithium-ion batteries. Specifically:

[0246] The composition of the mixed aqueous solution is Li + 0.338g / L, Ni 2+ 1.418g / L, Co 2+ 0.854 g / L, Mn 2+ 0.530 g / L, Fe 3 + 0.149g / L, Al 3+ 0.032 g / L, Ca 2+ 0.426 g / L, pH of the feed solution is 2.03.

[0247] Organic phases: such as NH-C8-1, NH-C8-5, NH-C8-6, NH-C8-7, NH-C8-8, HA-1 and L3 in Application Example 1.

[0248] The extraction conditions were the same as those for NH-C8-1 in Application Example 2. The test results are shown in Table 9.

[0249] Table 9. Effects of organic phase composition on polymetallic extraction behavior

[0250]

[0251] The results of this example show that the extractant alone cannot achieve the separation between metals, while the bidentate ligand alone exhibits co-extraction of iron. However, when the molar ratio of extractant / bidentate ligand is between 7:3 and 3:7, the extraction efficiency of nickel remains close to 100%, the extraction rate of cobalt is also at a high level, while the co-extraction of impurity ions (iron) is low, and the remaining impurity ions remain at a low level. The separation ability of nickel and cobalt from other metals is enhanced, indicating that the organic relative extraction solution provided by this invention has preferential extraction and separation capabilities for nickel and cobalt in the sulfuric acid leaching solution of decommissioned ternary lithium-ion batteries, and that the separation between nickel and cobalt can be achieved by combining it with application example 6.

[0252] Application Example 9

[0253] This example verifies the effect of pH environment of the mixed aqueous solution on the metal extraction efficiency of the organic phase. Specifically:

[0254] Mixed aqueous solution: sulfuric acid leachate from spent hydrogenation catalyst, containing Ni 2+ 0.562g / L, Co 2+ 0.348g / L, Al 3+ 9.37 g / L, Fe 3+ 0.056g / L

[0255] Using the NH-C8-1 and HA organic phases obtained in Application Example 1, single-stage extraction was performed on sulfuric acid leachates of waste hydrogenation catalysts at different pH values ​​(pH values ​​are shown in Table 10) to verify the effect of the pH of the aqueous solution to be extracted on the extraction rate. The specific extraction conditions were the same as in Application Example 2. The results are shown in Table 10.

[0256] Table 10 Effect of pH on extraction rate

[0257]

[0258] The results above show that, under different pH conditions, a single commercial DNNSA extractant cannot achieve selective separation of nickel. Using the organic phase provided by this invention, at an initial aqueous phase pH of 0.53 (equilibrium pH = 0.38), the extraction rate of nickel remains close to 100%, the extraction rate of cobalt remains around 40%, and the co-extraction of other impurities is low. As the initial pH increases, the equilibrium pH also increases, the extraction efficiency of nickel remains at a high level, and the extraction rate of cobalt increases significantly. This extraction system still conforms to the extraction mechanism of cation exchange in acidic extractants, and can selectively extract nickel in a strongly acidic environment (pH < 1), and achieve selective co-extraction of nickel and cobalt in a weakly acidic environment (pH ≈ 2), thus separating nickel, cobalt, and other impurity metals. Simultaneously, due to the intervention of bidentate ligands, the active hydrogen in the commercial DNNSA extractant has a stronger metal exchange capacity, resulting in a lower equilibrium pH of the raffinate phase at the same concentration of commercial DNNSA extractant.

[0259] Application Example 10

[0260] This example verifies the effect of temperature on the metal extraction behavior of organic phases, specifically:

[0261] Mixed aqueous solution: sulfuric acid leachate of sodium thiram cobalt residue, containing Co 2+ 0.685g / L, Zn 2+ 0.227g / L, Ni 2 + 0.003 g / L, Fe 2+ 0.018g / L, Mn 2+ 0.011 g / L, Cd 2+ 0.001 g / L, pH of the solution is 2.04;

[0262] The organic phase used was the NH-C8-1 organic phase obtained in Application Example 1, with an O / A ratio of 1:1, a mixing time of 10 min, a stirring rate of 600 rpm, and an extraction temperature range of 10–50 °C. The specific temperatures and results are shown in Table 11.

[0263] Table 11 Effect of different temperatures on metal extraction efficiency

[0264]

[0265]

[0266] The results show that within the temperature range of 10–50°C, the organic phase has little effect on the extraction efficiency of nickel and cobalt, but a significant impact on the extraction behavior of zinc, indicating that the extraction of zinc by this organic phase is significantly affected by thermodynamics. Cadmium exhibits significant co-extraction, but its content is low and easily removed by the organic phase. Furthermore, the mixed aqueous solution in this application example is cobalt-rich and nickel-poor. Since the affinity of bidentate ligands for cobalt is second only to nickel, the extraction rate of cobalt increases significantly when the nickel concentration in the mixed aqueous solution decreases. Moreover, in this example, the high cobalt content eliminates the need for repeated high-acidity back-extraction to obtain small amounts of nickel from the organic phase; only a large amount of nickel back-extraction is required from the repeatedly circulated extracted organic phase to obtain a fresh blank organic phase.

[0267] As can be seen from all the application examples, the organic phase provided by the present invention has high versatility. It can extract nickel and cobalt from polymetallic sulfuric acid solutions containing nickel and cobalt (leaching solutions from ores, decommissioned batteries, waste catalysts, etc.), and can further separate nickel and cobalt, and achieve a high extraction rate for both.

[0268] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. An organic phase, characterized in that, The raw materials for preparing the organic phase include an extractant and a bidentate ligand; the extractant is dinonylnaphthalenesulfonic acid. The bidentate ligand has the structure shown in Formula I: ； Wherein, R is a C4 straight-chain alkyl, C6 straight-chain alkyl, C8 straight-chain alkyl, C 12 Straight-chain alkyl, C8 branched alkyl and C 12 One of the branched alkyl groups.

2. The organic phase according to claim 1, characterized in that, The method for preparing the bidentate ligand includes the following steps: S1. Nucleophilic substitution reaction of ethyl 2-pyridinecarboxylate and a methyl ketone with the structural formula CH3COR yields the intermediate shown in Formula II; S2. The intermediate product and hydrazine are reacted to synthesize Knorr pyrazole; ； 3. The organic phase according to claim 2, characterized in that, In step S1, the nucleophilic substitution reaction is carried out at a temperature of 50-70°C.

4. The organic phase according to claim 1, characterized in that, In the organic phase, the molar ratio of the extractant to the bidentate ligand is 0.25 to 4:

1.

5. The organic phase according to any one of claims 1 to 4, characterized in that, In the organic phase, the concentration of the extractant is 0.01~0.1 mol / L.

6. A method for extracting and separating Ni / Co from solution, characterized in that, The method comprises extracting a mixed aqueous solution with the organic phase as described in any one of claims 1 to 5; the aqueous solution contains ionic Ni and / or Co, as well as impurity ions; the impurity ions include Mn. 2+ Mg 2+ Al 3+ Ca 2+ Zn 2+ and Fe 3+ At least one of them.

7. The method according to claim 6, characterized in that, The method includes the following steps: A1. Extract the mixed aqueous solution with the organic phase to obtain the raffinate phase and the supported organic phase; the amount of extractant in the organic phase is greater than or equal to the theoretical amount of extractant required for Ni and Co in the mixed aqueous solution; A2. Back-extract the supported organic phase with sulfuric acid aqueous solution A to obtain an aqueous phase rich in impurity ions and an organic phase rich in nickel and cobalt; the hydrogen ion concentration in the sulfuric acid aqueous solution A is ≤0.2 mol / L; A3. Back-extract the nickel-cobalt-rich organic phase with sulfuric acid aqueous solution B to obtain a cobalt-rich aqueous phase and a nickel-rich organic phase; the hydrogen ion concentration in the sulfuric acid aqueous solution B is greater than 0.2 mol / L and not less than 2 mol / L; A4. Back-extract the nickel-rich organic phase with sulfuric acid aqueous solution C to obtain a nickel-rich aqueous phase and a blank organic phase; the hydrogen ion concentration in the sulfuric acid aqueous solution C is 4~6 mol / L; Alternatively, the method may include the following steps: B1. Extract the mixed aqueous solution with the organic phase to obtain raffinate phase A and nickel-supported organic phase; the amount of extractant in the organic phase is less than or equal to the theoretical amount of extractant required for Ni in the mixed aqueous solution; B2. Extract the raffinate phase A with the organic phase to obtain raffinate phase B and cobalt-supported organic phase; Alternatively, the method may include the following steps: C1. Extract the mixed aqueous solution with the organic phase to obtain an impurity raffinate phase and a nickel-cobalt supported organic phase; the amount of extractant in the organic phase is greater than the theoretical amount of extractant required for Ni in the mixed aqueous solution, and less than the theoretical amount of extractant required for Ni and Co in the mixed aqueous solution; C2. The nickel-cobalt supported organic phase is back-extracted with sulfuric acid aqueous solution B to obtain a cobalt-containing aqueous solution and a nickel-containing organic phase; the hydrogen ion concentration in the sulfuric acid aqueous solution B is greater than 0.2 mol / L and not less than 2 mol / L; C3. Back-extract the nickel-containing organic phase with sulfuric acid aqueous solution C to obtain a nickel-containing aqueous solution and a blank organic phase; the hydrogen ion concentration in the sulfuric acid aqueous solution C is 4~6 mol / L.

8. The application of an organic phase as described in any one of claims 1 to 5, or the method as described in any one of claims 6 to 7, in nickel ore mining and waste resource recycling.

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