Amino-containing bidentate ligand as well as preparation method and application thereof

Abstract

The invention discloses an amino-containing bidentate ligand as well as a preparation method and application thereof, and belongs to the technical field of hydrometallurgy. The amino-containing bidentate ligand provided by the invention has a pyridine ring and a pyrazole ring which are connected, and the pyrazole ring is also connected with an R group; wherein a pyridine ring and an R group are located at meta positions of a pyrazole ring and are both connected with a C atom. According to the bidentate ligand containing the amido, due to the fact that the bidentate ligand containing the amido leaves amido containing protons, the bidentate ligand containing the amido is matched with an extracting agent to obtain an organic phase, and the technical problems that when nickel and cobalt are extracted and separated through a traditional solvent, the extraction capacity of the organic phase is low, the nickel and cobalt selectivity and priority are low, and the service life of the organic phase is short can be solved. The invention also provides a preparation method and application of the bidentate ligand.

Description

Technical Field

[0001] The invention relates to the technical field of hydrometallurgy, and in particular to an amine-containing bidentate ligand and a preparation method and application thereof. Background Art

[0002] Nickel and cobalt, as important non-ferrous metals, are widely used in the fields of permanent magnets, alloys, and catalysts. At present, with the rise of new energy vehicles, the production center of lithium-ion batteries has gradually shifted from 3C consumer batteries to power batteries, and its production and consumption are increasing day by day. As important raw materials for the positive electrode materials (NCM) of ternary polymer lithium-ion batteries, the demand for nickel and cobalt has also increased. At present, the main source of nickel and cobalt is the hydrometallurgy of laterite nickel ore. With the promotion of electric vehicles and the passage of time, 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 have gradually become a source of raw materials for 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, resulting in increased difficulty in separating and extracting nickel and cobalt, which increases the process flow, energy consumption, production costs, and three waste emissions.

[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 is the co-extraction of metal impurities with nickel and cobalt. In the phosphoric acid extractants and extraction systems currently used, metal impurities are extracted before nickel and cobalt or have a similar extraction priority to nickel and cobalt. Therefore, impurities with low precipitation pH such as iron and aluminum need to be removed by precipitation, while impurities such as calcium, magnesium, manganese, and zinc are removed by multi-stage extraction. In order to achieve short-process separation of 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 constantly developing extractants and extraction systems that can selectively extract nickel and cobalt from leachates with complex components.

[0004] Since nitrogen atoms have excellent coordination properties for nickel and cobalt, a variety of nitrogen-containing extractants or ligands have been synthesized and studied, mainly including oxime and pyridine derivatives. However, oxime-based extractants are easily decomposed in the presence of organic acids, which limits the scope of application of this type of extractant; pyridine carboxylic acid ester extractants do not have such problems, and the synergistic extraction system composed of pyridine carboxylic acid ester extractants has been favored by researchers, but this synergistic extraction system has the problem that the ester bond is easily destroyed during the stripping process and the nickel-cobalt selectivity is not high enough.

[0005] In summary, the relevant extraction systems for nickel-cobalt extraction and separation either require complex extraction and separation processes, or the life of the extraction system is short, making it difficult to extract and separate nickel-cobalt from a complex solution system. Summary of the invention

[0006] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes an amine-containing bidentate ligand, and an organic phase obtained by combining with an extractant, which can solve the technical problems of low organic phase extraction capacity, low nickel-cobalt selectivity and priority, and short service life of the organic phase when separating nickel and cobalt by traditional solvent extraction.

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

[0008] The present invention also provides application of the bidentate ligand.

[0009] According to an embodiment of the first aspect of the present invention, there is provided an amine-containing bidentate ligand, wherein the bidentate ligand has a structure as shown in Formula I:

[0010]

[0011] Where R is C 4 ~C 12 of alkyl.

[0012] The bidentate ligand according to the embodiment of the present invention has at least the following beneficial effects:

[0013] The present invention proposes a ligand having a [N,N] bidentate structure and a proton-containing amine group, which acts as a hydrogen bond donor and a hydrogen bond acceptor, and can interact with an acidic extractant that is also a hydrogen bond donor and a hydrogen bond acceptor to form a hydrogen bond network, and the formed complex can participate in the inner layer coordination of nickel and cobalt ions. That is, the bidentate ligand provided by the present invention can significantly improve the extraction and separation efficiency of nickel and cobalt due to the structural design.

[0014] Compared with a ligand having a simple [N,N] bidentate structure but no protonated amine group (i.e., the substituent is on the amine group, hereinafter referred to as a traditional ligand), although the traditional ligand also exhibits an ion association mechanism for metal extraction, and the pH of the solution is almost unchanged before and after extraction, the traditional ligand does not have the inductive effect of the protonated amine group, nor does it have the characteristics of a hydrogen bond donor. Therefore, the traditional ligand has no extraction effect on nickel and cobalt (only has the role of assisting coordination); the bidentate ligand provided by the present invention has the additional ability to coordinate with nickel and cobalt due to the presence of the protonated amine group, and ion association occurs in the form of sulfate to capture nickel and cobalt; therefore, the bidentate ligand provided by the present invention significantly improves the extraction rate and saturation capacity of nickel and cobalt.

[0015] Furthermore, whether the amine group in the bidentate ligand contains protons or not has a significant impact on the synergistic effect between the amine group and the extractant. The synergistic extraction system composed of the traditional ligand and the extractant shows a strong anti-synergistic effect on metals other than nickel and cobalt, and the extraction rate of cobalt is kept at a low level, and the extraction saturation capacity of nickel is low; while the synergistic extraction system composed of the bidentate ligand and the extractant provided by the present invention can simultaneously ensure that the extraction rates of nickel and cobalt are high, and the extraction saturation capacity is significantly improved, and the bidentate ligand provided by the present invention has different affinities for nickel and cobalt, and nickel and cobalt can be further separated by stripping operation. Therefore, the introduction of protons on the amine group has a significant impact on the extraction behavior of nickel, cobalt and metal impurities.

[0016] Furthermore, in the bidentate ligand provided by the present invention, the long-chain alkyl group also ensures its oil solubility and hydrophobicity, promotes nickel and cobalt to enter the organic phase from the aqueous phase, and completes the separation from other metals, that is, accelerates phase separation; if the side chain is not a long-chain alkyl group, but contains a hydrophilic group such as a hydroxyl group, it will significantly affect the hydrophobicity of the bidentate ligand, and then affect its phase separation when applied to extraction; if the side chain is not a long-chain alkyl group, but an aromatic group 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 the present invention, and then affect the extraction behavior of related sites such as proton amine groups; in addition, the selection of the type of long-chain alkyl group also lays the foundation for the subsequent preparation method, that is, the selection of a suitable side chain structure can significantly improve the yield and purity of the bidentate ligand during the preparation process, and improve the stability of the bidentate ligand. From another perspective, the type and length of the side chain affect the practicality of the bidentate ligand in extraction to a certain extent, and at the same time simplify the preparation process.

[0017] In summary, the ligand provided by the present invention can show good selectivity for nickel and cobalt, while inhibiting the extraction of other impurity metal ions, and has the advantages of stable extractant structure, large saturation capacity, clear phase separation, etc.

[0018] According to some embodiments of the present invention, in the structure shown in Formula I, R is C 4 Straight chain alkyl, C 6 Straight chain alkyl, C 8 Straight chain alkyl, C 12 Straight chain alkyl, C 8 Contains branched alkyl and C 12 One of the branched alkyl groups.

[0019] According to some embodiments of the present invention, C 8 Branched chain alkyl groups include ethylhexyl.

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

[0021] According to some embodiments of the present invention, the bidentate ligand has a macroscopic form of a white solid substance. This is because the bidentate ligand has intramolecular hydrogen bonds. The macroscopic form of a traditional ligand is a yellow oily substance.

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

[0023] S1. Make 2-picolinic acid ethyl ester (CAS: 2524-52-9) and the structural formula CH 3 The methyl ketone of COR undergoes a nucleophilic substitution reaction to obtain an intermediate product shown in Formula II;

[0024] S2. subjecting the intermediate product to a Knorr pyrazole synthesis reaction with hydrazine;

[0025]

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

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

[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 comprises the following steps:

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

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

[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 to the sodium hydride is 1:1-2. For example, 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 tetrahydrofuran solution of sodium hydride, the mass volume ratio of sodium hydride (based on the actual mass of the crude product used) to tetrahydrofuran is 50-100 mg:1 mL, for example, specifically about 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 can be achieved.

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

[0037] According to some embodiments of the present invention, in step S1a, the target temperature of the heating is 50-70°C, for example, 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, 1.2 to 1.3 mol / L.

[0039] According to some embodiments of the present invention, in step S1b, the tetrahydrofuran solution of ethyl 2-pyridinecarboxylate is added for a time of ≤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 1:0.8-1.2, for example, specifically about 1:1.

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

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

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

[0044] The temperature of the cooled mixture is -5 to 5°C, for example, about -2°C, 0°C, or about 2°C.

[0045] After adjusting the pH, the pH range of the obtained mixture is 8 to 9. The pH adjuster used includes hydrochloric acid. The concentration of the hydrochloric acid used is 0.08 to 0.12 mol / L; for example, it can be about 0.1 mol / L.

[0046] The purification of the intermediate product comprises sequentially performing ether extraction, washing the obtained organic phase with brine, removing water from the obtained organic phase and vacuum concentration.

[0047] The O / A ratio of the ether extraction is 1:3-5, for example, specifically about 1:4.

[0048] The number of times of ether extraction is 4 to 6 times, for example, specifically 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 1:0.8-1.2; for example, it can be about 1:1.

[0051] The obtained organic phase is dehydrated by drying with magnesium sulfate.

[0052] The vacuum concentration has a vacuum degree of 0.08-0.09 MPa.

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

[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 to 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 the hydrazine hydrate in the ethanol solvent is 0.8-1 mol / L, for example, 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 to 100 minutes, for example, about 90 minutes.

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

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

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

[0062] The temperature of the reduced pressure distillation is 45 to 55°C; for example, it may be specifically about 50°C.

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

[0064] The method for removing the solvent includes vacuum removal of the solvent. The specific vacuum degree is ≥ 0.09 MPa. For example, it can be about 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 the third aspect of the present invention, an organic phase is provided, wherein raw materials for preparing the organic phase include an extractant and the bidentate ligand described in the first aspect of the present invention.

[0068] Since the organic phase adopts all the technical solutions of the bidentate ligand of the above embodiment, it at least has all the beneficial effects brought by the technical solutions of the above embodiment. Specifically:

[0069] In the organic phase provided by the present invention, since the bidentate ligand used acts as both a hydrogen bond donor and a hydrogen bond acceptor, there is an intermolecular interaction between it and commonly used extractants such as DNNSA, forming a hydrogen bond network effect, and the resulting molecular association body seizes the active hydrogen in the extractant, hindering the combination of impurity ions with the commonly used extractant, thereby achieving efficient preferential extraction of nickel and cobalt; further, since the organic phase provided by the present 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 concentration of the stripping agent. That is, the organic phase provided by the present invention is suitable for the separation and recovery of nickel and cobalt in complex compositions such as minerals or secondary resources.

[0070] The organic phase provided by the present invention is easy to separate from the water phase, not easy to emulsify, and does not need saponification. The introduction of the extractant improves the disadvantage of the bidentate ligand being hydrophilic and easy to emulsify, while not 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 of dinonylnaphthalenesulfonic acid (DNNSA, CAS: 25322-17-2), di(2-ethylhexyl)phosphonic acid (P204, CAS: 298-07-7), 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (P507, CAS: 14802-03-0), bis(2,4,4-trimethylpentyl)phosphinic acid (Cyanex272, CAS: 83411-71-6) and neodecanoic acid (V10, CAS: 26896-20-8). Compared with other commonly used extractants, the above acidic extractant is easier to form a hydrogen bond network with the bidentate ligand, so that the synergistic effect between the extractant and the bidentate ligand is more obvious.

[0072] According to some embodiments of the present invention, in the organic phase, the molar ratio of the extractant to the bidentate ligand is 0.25 to 4: 1. For example, 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, in the organic phase, the concentration of the extractant is 0.01-0.1 mol / L, for example, 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 the 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 the organic phase according to the embodiment of the third aspect of the present invention; the aqueous solution contains ionic Ni and / or Co, and impurity ions; the impurity ions include Mn 2+ Mg 2+ 、Al 3+ , Ca 2+ 、Zn 2+ and Fe 3+ At least one of .

[0077] Since the method adopts all the technical solutions of the organic phase in the above embodiment, it has at least all the beneficial effects brought by the technical solutions in the above embodiment. Specifically:

[0078] In the method, the organic phase is easily separated from the aqueous phase, is not easy to emulsify, and does not require saponification; the organic phase has different extraction priorities for impurity ions, nickel, and cobalt. Therefore, in actual production, nickel, cobalt, and impurity ions can be easily separated by controlling the extraction conditions or stripping conditions, thereby significantly reducing the difficulty of nickel / cobalt extraction and shortening the process. About the control of conditions. Some rules are as follows: Under low pH conditions (e.g., pH ≤ 2), the distribution coefficient between nickel / cobalt and other impurity metal ions and 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, Ni 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, Co 2+ ; Its concentration is 0.3-1.0 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] It can be seen from this that the method provided by the present invention is suitable for the extraction and separation of cobalt and nickel in a mixed aqueous solution with a low cobalt and nickel content and a high impurity content.

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

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

[0086] According to some embodiments of the present invention, the secondary resources include at least one of retired lithium-ion secondary batteries, retired sodium-ion secondary batteries, retired nickel-hydrogen batteries, Fumei cobalt slag and retired nickel-containing catalysts. In other words, all retired materials containing nickel or cobalt are applicable.

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

[0088] A1. extracting the mixed aqueous solution with the organic phase to obtain a raffinate phase and a loaded organic phase; the amount of the extractant in the organic phase is ≥ the theoretical amount of the extractant required for Ni and Co in the mixed aqueous solution;

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

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

[0091] A4. The nickel-rich organic phase is back-extracted with an aqueous sulfuric acid solution C to obtain a nickel-rich aqueous phase and a blank organic phase; the hydrogen ion concentration in the aqueous sulfuric acid solution C is 4 to 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. For example, 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, sulfuric acid or sodium hydroxide can be used as a pH adjuster. Usually, the value range can be adjusted by changing the initial pH of the aqueous phase 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. For example, it can be about 1:2, 1:1, 2:1 or about 1:3. In actual production, the actual amount of the extractant in the extraction can be further adjusted by adjusting the concentration and other components 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; for example, it can be about 10 minutes. This time is the time for the organic phase and the aqueous phase to mix. The mixing means includes at least one of shaking and stirring. When the mixing means is stirring, the stirring speed is 500 to 700 rpm, for example, 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. Usually, ambient temperature is sufficient, and no additional temperature adjustment is required. For example, it can be room temperature in the traditional sense, that is, about 25°C; it can also 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 aqueous sulfuric acid 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 stripping is 1:1-5; for example, it may be 1:2.

[0098] According to some embodiments of the present invention, in step A2, the stripping time is 5 to 15 minutes; for example, 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 back extraction temperature is 20-30°C, for example, about 25°C.

[0100] In the stripping of step A2, the obtained impurity ion-rich aqueous phase may also include cobalt. Specifically, the proportion of cobalt is determined by the O / A ratio, stripping acidity, time and composition of the loaded organic phase in the stripping in step A2. From another perspective, the affinity of the organic phase to cobalt ions is slightly stronger than that of impurity ions represented by zinc ions, but far less than the affinity of the organic phase to nickel ions. Therefore, for the loaded organic phase containing nickel, cobalt and impurity ions at the same time, if the stripping acidity is slightly high, part of the cobalt in the loaded organic phase may be brought into the impurity ion-rich aqueous phase; since the extraction priority of the loaded organic phase to impurity ions is not as high as that of nickel and cobalt, controlling the amount of the organic phase or the acid concentration of the stripping in step A2 can reduce the impurity ions entrained in the loaded organic phase, thereby eliminating the zinc washing process; or reduce the loss of cobalt during the stripping process.

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

[0102] According to some embodiments of the present invention, in step A3, the stripping time is 5 to 15 minutes; for example, 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 back extraction temperature is 20-30°C, for example, about 25°C.

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

[0105] According to some embodiments of the present invention, in step A4, the stripping time is 5 to 15 minutes; for example, 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 back extraction temperature is 20-30°C, for example, about 25°C.

[0107] It should be noted that the stripping conditions in steps A2 to A4, except for the acid aqueous solution used, may be the same or different.

[0108] According to some embodiments of the present invention, the method further comprises, after step A4, washing the blank organic phase 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 comprises the following steps:

[0110] B1. extracting the mixed aqueous solution with the organic phase to obtain a raffinate phase A and a nickel-loaded organic phase; the amount of the extractant in the organic phase is ≤ the theoretical amount of the extractant required for Ni in the mixed aqueous solution;

[0111] B2. extracting the raffinate phase A with the organic phase to obtain a raffinate phase B and a cobalt-loaded organic phase.

[0112] The mechanism of steps B1 to B2 is as follows:

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

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

[0115] The method of steps B1 to B2, through two simple extractions, can efficiently extract nickel and cobalt from a multi-mixed aqueous solution, and further separate the two to obtain a nickel-based aqueous solution and a cobalt-based aqueous solution of higher purity; compared with traditional extraction, the process of nickel / cobalt separation is greatly simplified, and the extraction cost is reduced. In the process, by adjusting the amount of organic phase in step B1, the extraction selectivity of step B1 is higher, the loaded organic phase contains only nickel, and a nickel-based aqueous solution of higher purity can be obtained by direct back extraction; and in the extraction of step B2, due to the residual nickel ions in the raffinate phase A. Therefore, the cobalt-loaded organic phase contains a small part of nickel and most of the cobalt ions, and then 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; and the nickel-poor loaded organic phase can continue to enter the extraction operation after washing, 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 may be about 10 minutes.

[0117] In step B1, other conditions related to extraction may refer to the condition selection range of step A1, and the specific selection point values ​​may be the same as or different from those of step A1.

[0118] According to some embodiments of the present invention, step B1 further comprises stripping the nickel-loaded 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.

[0119] The stripping agent used for stripping the nickel-loaded organic phase is the sulfuric acid aqueous solution C; the specific stripping conditions can refer to the stripping condition range of step A3, and 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, and can also be reused as the organic phase in step B2, thereby saving the reagent cost of the method.

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

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

[0123] According to some embodiments of the present invention, step B2 further includes stripping the cobalt-loaded organic phase to obtain a cobalt-based aqueous solution and a nickel-depleted organic phase; the nickel-depleted organic phase is returned to step B1, mixed with the nickel-loaded organic phase, and subjected to unified stripping.

[0124] In step B2, after stripping cobalt, there is still a small amount of nickel in the organic phase because, in order to improve the purity of the nickel-loaded organic phase, the amount of organic phase used in step B1 will be slightly lower than its theoretical requirement, so the raffinate phase A still contains a small amount of nickel, which will enter the organic phase with the extraction in step B2.

[0125] The stripping agent used for stripping the cobalt-loaded organic phase is the aqueous sulfuric acid solution B; for specific stripping conditions, refer to the stripping condition range of step A2, and the specific selection point value may be the same as or different from that of step A2.

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

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

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

[0129] C3. The nickel-containing organic phase is back-extracted 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 to 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 condition selection range of the extraction in step A1; the specific selection point value may be the same as or different from that in step A1.

[0131] According to some embodiments of the present invention, in addition to the limiting conditions, the stripping of step C2 and step C3 refers to the stripping condition selection range in step A2; the specific selection point value may be the same as or different from step A2.

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

[0133] If not otherwise specified, the theoretical amount of the extractant in the method is based on its saturated capacity, more specifically, the saturated capacity of a specific organic phase; the amount of the extractant (actual amount) is related to the O / A ratio of the extraction process and the composition of the organic phase.

[0134] Unless otherwise specified, the extraction in the method is a single-stage extraction, which significantly saves the operation process of the method.

[0135] Unless otherwise specified, in the method, the washing refers to washing with deionized water. It can be seen that the organic phase including the bidentate ligand has a simple regeneration method, which further reduces the difficulty of nickel / cobalt extraction in terms of operation. The deionized water washing has an O / A ratio of 1:0.8 to 1.2, for example, specifically about 1:1; the deionized water washing time is 3 to 8 minutes; for example, specifically about 5 minutes.

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

[0137] Since the application adopts all the technical solutions of the bidentate ligand, or organic phase or method of the above embodiment, it has at least all the beneficial effects brought by the technical solutions of the above embodiment. That is,

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

[0139] According to some embodiments of the present invention, in the waste resource recycling, the waste resources used include at least one of retired lithium-ion secondary batteries, retired sodium-ion secondary batteries, retired nickel-hydrogen batteries, Fumei cobalt slag and retired nickel-containing catalysts. That is, in fact, retired materials containing nickel or cobalt are all applicable.

[0140] If there is no special explanation, the actual meaning of “about” in the present invention is that the error is allowed to be within the range of ±2%, for example, about 100 is actually 100±2%×100.

[0141] Unless otherwise specified, “between” in the present 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 present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

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

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

[0147] Figure 4 is the H NMR spectrum of the bidentate ligand prepared in Example 1 of the present invention;

[0148] Figure 5 is the NMR carbon spectrum of the bidentate ligand prepared in Example 1 of the present invention;

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

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

[0151] Figure 8 It is a schematic diagram of the synergistic effect between the bidentate ligand and the extractant in the organic phase provided in the application example of the present invention. DETAILED DESCRIPTION

[0152] The following will be combined with the embodiments to clearly and completely describe the concept of the present invention and the technical effects produced, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0153] In the description of the present invention, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0154] If there is no special description, the distribution ratio D, separation coefficient β, extraction rate E in the specific implementation method are x (%), stripping rate E s (%) are calculated according to formula (1) to formula (5):

[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] Among them, C in formula (1) MOrg , C MAq are the concentrations of metal ions M in the loaded organic phase and the raffinate phase (mol / L), respectively; β in formula (2) and formula (3) Ni / M , β Co / M Respectively represent the separation coefficients of Ni, Co and impurity M; D Ni , D Co , D M Respectively represent the distribution ratio of Ni, Co, and impurity M; in formula (4), C M0 , represents the initial concentration of metal ion M in the aqueous phase to be extracted (mol / L); C in formula (5) Ms represents the metal ion concentration of the stripping solution (mol / L), V s , V Org represent the volumes of the stripping solution and the loaded organic phase, respectively.

[0161] Example 1

[0162] In this example, a bidentate ligand containing a protonated amine group was prepared. The specific steps are as follows:

[0163] S1. Nucleophilic substitution reaction:

[0164] S1a. 2-decanone (methyl octyl ketone, CAS: 693-54-9) and a tetrahydrofuran solution of sodium hydride were stirred and mixed at room temperature (about 25°C) for 20 minutes, and heated to 60°C; wherein,

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

[0166] The mass volume ratio of sodium hydride (calculated as 60 wt % of the actual mass used) and tetrahydrofuran is 80 mg / mL.

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

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

[0169] The molar ratio of ethyl 2-pyridinecarboxylate and 2-decanone used was 1:1.

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

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

[0172] The O / A ratio used in the ether extraction was 1:4, and the number of extractions was 5.

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

[0174] S2. Within 10 minutes after the end of step S1d, the intermediate product 1-(pyridin-2-yl)heptane-1,3-dione and hydrazine hydrate were mixed in ethanol and refluxed 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 mixture obtained from the reflux reaction was subjected to reduced pressure distillation (vacuum degree of 0.08 MPa, temperature of 50°C) to remove the solvent, and then impurities were removed by silica gel column chromatography, wherein toluene was used as a decontamination agent to remove impurities in the sample, and ethyl acetate was used as an eluent to elute the product in the column; finally, the solvent was removed by high vacuum (vacuum degree of 0.1 MPa) to obtain a bidentate ligand in the form of a white powder.

[0178] Example 2

[0179] In this example, a bidentate ligand containing a protonated amine group was prepared, where R is C 4 Straight chain alkyl, the specific steps are different from those in Example 1:

[0180] The 2-decanone in step S1 was replaced with an equal amount of 2-hexanone (CAS: 591-78-6).

[0181] Example 3

[0182] In this example, a bidentate ligand containing a protonated amine group was prepared, where R is C 12 Straight chain alkyl, the specific steps are different from those in Example 1:

[0183] The 2-decanone in step S1 was replaced with an equal amount of 2-tetradecanone (methyl dodecyl ketone, CAS: 2345-27-9).

[0184] Example 4

[0185] In this example, a bidentate ligand containing a protonated amine group was prepared, in which R is a branched C 12 Alkyl, the specific steps are different from those in Example 1:

[0186] The 2-decanone in step S1 was replaced with an equal amount of 3-butyldecan-2-one (methyl butyldecanyl ketone, Pubchem CID 54205874).

[0187] Test Example 1

[0188] This example tests the infrared and nuclear magnetic resonance results of the bidentate ligands obtained in Examples 1 to 4 to prove that the present invention has indeed synthesized the corresponding bidentate ligands, and places them in an air environment for thermogravimetric testing to detect the thermal stability of the ligands under industrial conditions. The results of the nuclear magnetic hydrogen spectrum show an obvious -NH (i.e., containing a proton amine group) peak, which shows that in the preparation method provided by the present invention, the alkyl chain is indeed not directly connected to the proton amine group; and the combination of the nuclear magnetic hydrogen spectrum and the nuclear magnetic carbon spectrum shows that the number of H and C is exactly the same as that of the bidentate ligand designed by the present invention; correspondingly, the infrared spectrum also has significant evidence for the structure of the bidentate ligand. Specifically, the nuclear magnetic resonance results of Example 1 are as follows: Figures 4-5 As shown, the infrared results are Figure 6 In addition, the thermogravimetric results show that the bidentate ligand provided by the present invention starts to lose weight at 160°C and loses weight rapidly in the range of 160-350°C, which indicates that the use temperature of the bidentate ligand provided by the present invention only needs to be lower than 160°C. The thermogravimetric results of Example 1 are shown in FIG. Figure 7 shown.

[0189] In addition, the NMR results of Example 2 are as follows:1 H NMR (500 MHz, DMSO-d 6 )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 of Example 3 are as follows: 1 H NMR (500 MHz, DMSO-d 6 )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 of Example 4 are as follows: 1 H NMR (500 MHz, DMSO-d 6 )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=6.5Hz,1H),6.5 9(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 illustrate that Examples 2 to 4, like Example 1, produced 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 in Application Example 1 to extract the mixed aqueous solution, and calculates the extraction rates of nickel, cobalt and impurity metal ions by these four organic phases. Specifically:

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

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

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

[0203] Table 2 Extraction rate of organic phase to different metal ions in Application Example 2

[0204]

[0205]

[0206] According to the above results, there are great differences between the L1 group and the L2 group in themselves and in the synergistic extraction system. The L1 group itself did not show high extraction rate and selectivity for the metals contained in the solution. In the synergistic extraction system C8-1, L1 can show good selectivity and extraction performance for nickel, slightly improve the extraction performance of cobalt, and show antagonism to other metals; while L2 itself shows high extraction rate for nickel, cobalt, iron, and zinc. This is due to its protonated amine group. After being introduced into the synergistic extraction system NH-C8-1, L2 shows high selectivity for nickel and cobalt, and zinc has slight co-extraction, and the extraction rates of other metals are kept at a low level. The common point of the ligands in L1 and L2 is that their own extraction mechanism is ion association, and the pH of the solution before and after extraction is almost unchanged; L2, by virtue of the stronger association energy between the protonated amine group and the metal salt ion, exhibits certain extraction performance and specific extraction of nickel, cobalt, and iron; when introduced into the acidic extractant (DNNSA) extraction system, the extraction system exhibits a cation exchange mechanism, and the protons lacking in L1 are supplemented, so that the system has extraction performance, and the synergistic system exhibits certain selectivity for nickel and cobalt; the interaction between L2 and DNNSA inhibits the co-extraction of iron and zinc, so that nickel and cobalt can be separated from the mixed solution of multiple metals, showing an extraction capacity far superior to that of the L1 system. This shows that the presence of the protonated amine group in the bidentate ligand provided by the present invention has a significant effect on the extraction behavior of metal ions in the mixed solution, and at the same time affects the extraction saturation capacity and selectivity of the organic phase.

[0207] Application Example 3

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

[0209] Table 3 Properties of the organic phase including different branched ligands

[0210]

[0211]

[0212] The results show that the growth of alkyl chains or the presence of branching (C 8 and above) make the bidentate ligand sterically more hindered, the metal is blocked from entering the coordination layer, and the extraction rate is reduced to a certain extent; in the organic phase containing short alkyl chain bidentate ligands (NH-C 4), the extraction rates of nickel and cobalt decreased due to the partial coordination occupied by impurity metals; in the organic phase containing branched bidentate ligands, the larger steric hindrance affected the interaction between the bidentate ligand and the extractant, resulting in a decrease in the extraction rates of metals with stronger affinity to the bidentate ligands, and a certain increase in the extraction rate of impurities, but 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, and at the same time affect the interaction between the bidentate ligand and the extractant, thereby changing the inhibition of organic phases on impurities and the extraction behavior of nickel and cobalt.

[0213] Application Example 4

[0214] In this example, the organic phases numbered L2, HA and NH-C8-1 obtained in Application Example 1 were used for single-stage extraction of the sulfuric acid leaching solution of laterite nickel ore (the same mixed aqueous solution as in Application Example 2) (the extraction conditions were the same as in Application Example 2) to verify the influence of different organic phases on the extraction behavior of metal ions in the mixed aqueous solution. 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 rate of each metal ion is shown in Table 4, and the distribution ratio and separation coefficient are shown in Table 5.

[0216] Table 4 Extraction rate of metal ions by different organic phases in Application Example 4

[0217]

[0218] Table 5 Separation coefficient and distribution ratio between nickel, cobalt and other metals in Application Example 4

[0219]

[0220]

[0221] According to the above results, the commercial DNNSA extractant (HA) alone is used to extract nickel and cobalt, showing poor selectivity. It shows certain extraction performance for the metals contained in the solution, and its priority is Al>Fe>Zn>Ca>Co>Ni>Mg; while the bidentate ligand (L2 group) alone can achieve a higher extraction rate for extracting nickel and cobalt, but due to the co-extraction of iron and zinc, nickel and cobalt cannot be separated from impurities; at the same time, the extraction process has the problem of difficult phase separation and the generation of the third phase. When the mixed system (NH-C8-1) of the two is used to extract nickel, the extraction rate of nickel is close to 100%, and the extraction rate of cobalt can reach more than 85%, and the addition of commercial DNNSA successfully inhibits the co-extraction of iron, and the extraction rate of Fe, Al, Ca, and Mg impurity metals is less than 2%. There is a slight co-extraction of zinc, which improves the oil-water phase and the generation of the third phase. This shows that in the organic phase provided by the present invention, the interaction between the extractant and the bidentate ligand successfully inhibits the extraction of impurity metals, realizes the separation of nickel, cobalt and other impurity metals, and shows faster reaction kinetics. In the organic phase, the synergistic effect between the extractant and the bidentate ligand occurs as follows: Figure 8 shown.

[0222] It can also be found from the results that the separation coefficients of Ni, Co and other metal impurities (except zinc) are very high, and the separation coefficients of both for zinc are also above 30. Therefore, the organic phase provided by the present invention can separate nickel, cobalt and other metals by single-stage extraction, and the bidentate ligand containing an amine group is more easily applied to industrial extraction after the introduction of an extractant.

[0223] Application Example 5

[0224] In this example, the organic phase NH-C 8 -1 Single-stage extraction was performed on the laterite nickel ore sulfuric acid leaching solution (the same mixed aqueous solution as in Application Example 2) to verify the effect of the O / A ratio in the extraction process on the extraction effect. The remaining extraction conditions were consistent with those in Application Example 2. The corresponding relationship between the extraction effect and the O / A ratio is shown in Table 6.

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

[0226]

[0227]

[0228] The results show that as the O / A ratio decreases, the extraction rates of metal ions all decrease, and the extraction rates of cobalt, zinc, and iron decrease sharply. The extraction rates of other impurity metals remain at a low level, while the extraction rate of nickel decreases but its organic phase loading increases. The reason for this phenomenon is that after the organic phase is fully loaded with nickel at a high O / A ratio, there are still free extractant-ligand association molecules that coordinate with cobalt, zinc, and iron (extractant excess), so there is co-extraction of zinc and iron, which also reflects that the priority order of metal extraction in the system is Ni>Co>Zn>Fe; when the O / A ratio is low, there is an excess of nickel ions in the aqueous phase, the organic phase loads nickel to saturation, and other metals can no longer enter the coordination, so the extraction rates of cobalt, zinc, and iron decrease sharply. Adjusting the appropriate O / A ratio can better separate nickel, cobalt, and impurities. Taking into account the separation coefficients of nickel, cobalt and impurity metals and their extraction rates, the system has the best separation effect on each metal when O / A=1:1, with the nickel extraction rate close to 100%, the cobalt extraction rate above 85%, the zinc extraction rate around 20%, and the other impurity metal extraction rates at a lower level. Single-stage extraction can achieve the initial separation of nickel, cobalt and other metal impurities. However, this ratio is affected by the composition of the mixed aqueous solution to be extracted and the composition of the organic phase. If the above conditions change, the O / A ratio may also change accordingly.

[0229] Application Example 6

[0230] This example uses the loaded organic phase obtained from the NH-C8-1 group in Example 4 for stripping, and verifies the effect of the acidity of the sulfuric acid solution used for stripping on the stripping efficiency. Specifically:

[0231] The O / A ratio of the stripping was 1:1, the mixing time was 10 min, the stirring rate was 600 rpm, and the temperature was 25°C.

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

[0233] Table 7 Effect of acidity of aqueous phase used for stripping on stripping efficiency

[0234]

[0235] The results show that under low acidity, the zinc co-extracted in the organic phase can be successfully separated from nickel and cobalt and returned to the aqueous phase; with the increase of acidity, the stripping rate of cobalt increases significantly, while the stripping rate of nickel is still at a low level, especially when the hydrogen ion concentration is 2 mol / L, the stripping rate of cobalt is close to 100%, while the stripping rate of nickel is below 5%. Therefore, the stripping operation under this acidity condition can achieve the separation between nickel and cobalt. When the acidity is further increased to a hydrogen ion concentration of 4 mol / L, cobalt, zinc, and nickel in the loaded organic phase are stripped into the aqueous phase.

[0236] According to the above results, in the extraction process of the organic phase provided by the present invention, the metals co-extracted in the organic phase can be separated by controlling the stripping acidity: low acidity removes impurity metals, higher acidity separates cobalt and nickel, and high acidity strips nickel, and the target metal can be separated and purified without other steps. In other words, Figure 1 The process of the method shown in is feasible and has high efficiency.

[0237] Application Example 7

[0238] In this example, the NH-C 8 -2, NH-C 8 -3, NH-C 8 -4 organic phase was used to verify the effect of the extractant and the amount of extractant in the organic phase on the extraction behavior of the laterite nickel ore sulfuric acid leaching solution (the composition is the same as the mixed aqueous solution used in Application Example 2). The specific extraction conditions are the same as those 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 show that as the amount of extractant increases, the organic phase extraction rate of Ni, Co, and Zn increases significantly, while the extraction rate of other impurities remains at a relatively low level. At low extractant dosages, due to the strong affinity of the bidentate ligand provided by the present invention for nickel, the extraction rate of nickel can be maintained at a relatively high level (>85%), and the organic phase is close to saturation, so that almost no impurities are extracted. According to the priority order of the ligand's affinity for metals, cobalt is second only to nickel.

[0242] therefore, Figure 2 The method shown is feasible, that is, the nickel-loaded organic phase is reversely extracted, washed, and then the cobalt-containing raffinate phase A is extracted; when the amount of organic phase is appropriate, the nickel extraction rate is close to 100%, and the cobalt extraction rate is about 60%, while the co-extraction of impurity metals is less. Figure 3 The method flow shown is also feasible, that is, adjusting the amount of organic phase (or the amount of extractant therein) to achieve co-extraction of nickel and cobalt to obtain a nickel-cobalt loaded organic phase, and then combining with Application Example 6, the nickel and cobalt in the nickel-cobalt loaded organic phase are separated by controlling the acidity of the stripping aqueous phase, and the cobalt-containing impurity raffinate phase is returned to the aqueous solution to be mixed; and Application Example 6 provides, as Figure 1 In the method process, an excess of extractant is required. At this time, the extraction rates of nickel and cobalt are close to 100%, while there is partial co-extraction of zinc (extraction rate of about 40%); through the three-stage stripping of low acid-relatively high acid-high acid, an impurity ion-rich aqueous phase, a cobalt-rich aqueous phase and a nickel-rich aqueous phase can be obtained respectively.

[0243] Figures 1 to 3 In the three pathways shown, the organic phase is recycled after washing and regeneration, but the processes are quite different. Figure 1 The process shown in the figure consists of a single-stage extraction, three-stage stripping and one-stage regeneration operation, which has high extraction efficiency, short process, simple operation, and the presence of zinc as a byproduct, and low operating cost. However, the large amount of extractant used leads to high raw material cost; Figure 2 The shown route consists of two-stage extraction, two-stage stripping and two-stage regeneration operations. The amount of extractant used is small, the cost of raw materials is low, and the recycling rate of the organic phase in the process is higher. However, the two-stage extraction makes the operation more complicated, the process is longer, and the equipment cost is higher. Figure 3 The path shown consists of a single-stage extraction, two-stage stripping and one-stage regeneration operation. The amount of extractant used is appropriate, the raw material cost is low, and only the target metals-nickel and cobalt are extracted under the operating conditions. The extraction efficiency is higher, the process is short, and the operation is simple. However, the amount of extractant needs to be calculated and designed according to the composition of the liquid to be extracted. The three paths have their own advantages and disadvantages, but they are all easy to apply in industrial production.

[0244] Application Example 8

[0245] This example verifies the effect of the molar ratio of bidentate ligand and extractant in the organic phase on the extraction behavior of sulfuric acid leachate (mixed aqueous solution) of 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+ 0.854g / L, Mn 2+ 0.530g / L, Fe 3 + 0.149g / L、Al 3+ 0.032g / L, Ca 2+ 0.426g / L, the pH value of the feed solution is 2.03.

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

[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 Effect of organic phase composition on multi-metal 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 has co-extraction of iron. However, when the molar ratio of the 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, and the co-extraction of impurity ions (iron) is low, and the remaining impurity ions are all maintained at a low level. The separation ability of nickel, cobalt and other metals is enhanced, indicating that the organic phase provided by the present invention has preferential extraction and separation ability for nickel and cobalt in the sulfuric acid leachate of retired ternary lithium-ion batteries, and the separation of nickel and cobalt can be achieved in combination with Application Example 6.

[0252] Application Example 9

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

[0254] Mixed aqueous solution: sulfuric acid leaching solution of spent hydrogenation catalyst, which contains Ni 2+ 0.562g / L, Co 2+ 0.348g / L、Al 3+ 9.37g / L, Fe 3+ 0.056g / L,

[0255] Using the NH-C obtained in Application Example 1 8 -1 organic phase and HA organic phase, single-stage extraction of sulfuric acid leaching solution of spent hydrogenation catalyst with different pH (pH as shown in Table 10) was carried out to verify the effect of pH of the aqueous solution to be extracted on the extraction rate. The specific extraction conditions are the same as those in Application Example 2. The results are shown in Table 10.

[0256] Table 10 Effect of pH on extraction rate

[0257]

[0258] The above results show that: under different pH conditions, a single commercial DNNSA extractant cannot achieve the selective separation of nickel. Using the organic phase provided by the present invention, when the initial pH of the aqueous phase is 0.53 (equilibrium pH = 0.38), the extraction rate of nickel is still close to 100%, the extraction rate of cobalt is maintained at about 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; the extraction system still conforms to the extraction mechanism of cation exchange of acidic extractants, and can selectively extract nickel in a strongly acidic environment (pH <1), and selectively extract nickel and cobalt in a weakly acidic environment (pH≈2), and separate nickel, cobalt and other impurity metals. At the same time, due to the intervention of bidentate ligands, the active hydrogen in the commercial DNNSA extractant has a stronger ability to exchange metals, so that the equilibrium pH of the raffinate phase is lower at the same concentration of commercial DNNSA extractant dosage.

[0259] Application Example 10

[0260] This example verifies the effect of temperature on the extraction behavior of metals from organic phases. Specifically:

[0261] Mixed aqueous solution: sulfuric acid leaching solution of sodium fumei cobalt slag, which contains Co 2+ 0.685g / L, Zn 2+ 0.227g / L, Ni 2 + 0.003g / L, Fe 2+ 0.018g / L, Mn 2+ 0.011g / L, Cd 2+ 0.001g / L, pH of the feed solution is 2.04;

[0262] The organic phase adopts the NH-C 8 -1 organic phase, O / A ratio was 1:1, mixing time was 10 min, stirring rate was 600 rpm, extraction temperature range was 10-50 °C, specific temperature and results are shown in Table 11.

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

[0264]

[0265]

[0266] According to the above results: within the temperature range of 10-50°C, the organic phase has little effect on the extraction efficiency of nickel and cobalt, but has a more significant effect on the extraction behavior of zinc, indicating that the organic phase's extraction of zinc is significantly affected by thermodynamics; while cadmium has a more serious co-extraction, but its content is relatively small, making it easy to remove impurities from the organic phase. On the other hand, the composition of the mixed aqueous solution in this application example is cobalt-rich and nickel-poor, because the bidentate ligand's affinity for cobalt is second only to nickel. Therefore, when the concentration of nickel in the mixed aqueous solution decreases, the extraction rate of cobalt is greatly improved, and in this example, the cobalt content is high, so the stripping process does not need to repeatedly use high-acid stripping to obtain a small amount of nickel in the organic phase. It is only necessary to strip a large amount of nickel from the organic phase that has been circulated many times to obtain a fresh blank organic phase.

[0267] Combining all the application examples, it can be seen that the organic phase provided by the present invention has high universality, and can realize the extraction of nickel and cobalt for polymetallic sulfuric acid solutions containing nickel and cobalt (leaching solutions of ores, retired batteries, waste catalysts, etc.), and can further realize the separation between nickel and cobalt, and the two can also achieve a higher extraction rate.

[0268] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A bidentate ligand containing an amine group, characterized in that: The bidentate ligand has a structure as shown in Formula I: Among them, R is C4~C 12 of alkyl.

2. A method for preparing an amine-containing bidentate ligand according to claim 1, characterized in that: The preparation method comprises the following steps: S1. allowing ethyl 2-picolinate and a methyl ketone having a structural formula of CH3COR to undergo a nucleophilic substitution reaction to obtain an intermediate product of formula II; S2. subjecting the intermediate product to a Knorr pyrazole synthesis reaction with hydrazine; 3. The preparation method according to claim 2, characterized in that: In step S1, the temperature of the nucleophilic substitution reaction is 50-70°C.

4. An organic phase, characterized in that The raw materials for preparing the organic phase include an extractant and the bidentate ligand as claimed in claim 1.

5. The organic phase according to claim 4, characterized in that The extractant includes at least one of dinonylnaphthalenesulfonic acid, di(2-ethylhexyl)phosphonic acid, 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester, bis(2,4,4-trimethylpentyl)phosphinic acid and neodecanoic acid.

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

1.

7. The organic phase according to any one of claims 4 to 6, characterized in that In the organic phase, the concentration of the extractant is 0.01-0.1 mol / L.

8. A method for extracting and separating Ni / Co from a solution, characterized in that: The method comprises extracting a mixed aqueous solution with the organic phase according to any one of claims 4 to 7; the aqueous solution contains ionic Ni and / or Co, and impurity ions; the impurity ions include Mn 2+ Mg 2+ 、Al 3+ , Ca 2+ 、Zn 2+ and Fe 3+ At least one of .

9. The method according to claim 8, characterized in that The method comprises the following steps: A1. extracting the mixed aqueous solution with the organic phase to obtain a raffinate phase and a loaded organic phase; the amount of the extractant in the organic phase is ≥ the theoretical amount of the extractant required for Ni and Co in the mixed aqueous solution; A2. stripping the loaded organic phase with an aqueous sulfuric acid solution A to obtain an impurity ion-rich aqueous phase and a nickel-cobalt-rich organic phase; the hydrogen ion concentration in the aqueous sulfuric acid solution A is ≤0.2 mol / L; A3. stripping the nickel-cobalt-rich organic phase with an aqueous sulfuric acid solution B to obtain a cobalt-rich aqueous phase and a nickel-rich organic phase; the hydrogen ion concentration in the aqueous sulfuric acid solution B is greater than 0.2 mol / L and not less than 2 mol / L; A4. The nickel-rich organic phase is back-extracted with an aqueous sulfuric acid solution C to obtain a nickel-rich aqueous phase and a blank organic phase; the hydrogen ion concentration in the aqueous sulfuric acid solution C is 4 to 6 mol / L; Or, the method comprises the following steps: B1. extracting the mixed aqueous solution with the organic phase to obtain a raffinate phase A and a nickel-loaded organic phase; the amount of the extractant in the organic phase is ≤ the theoretical amount of the extractant required for Ni in the mixed aqueous solution; B2. extracting the raffinate phase A with the organic phase to obtain a raffinate phase B and a cobalt-loaded organic phase; Or, the method comprises the following steps: C1. extracting the mixed aqueous solution with the organic phase to obtain an impurity raffinate phase and a nickel-cobalt loaded organic phase; the amount of the extractant in the organic phase is greater than the theoretical amount of the extractant required for Ni in the mixed aqueous solution, and less than the theoretical amount of the extractant required for Ni and Co in the mixed aqueous solution; C2. stripping the nickel-cobalt loaded organic phase with an aqueous sulfuric acid solution B to obtain an aqueous cobalt-containing solution and an organic phase containing nickel; the hydrogen ion concentration in the aqueous sulfuric acid solution B is greater than 0.2 mol / L and not less than 2 mol / L; C3. The nickel-containing organic phase is back-extracted 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 to 6 mol / L.

10. Use of the bidentate ligand according to claim 1, or the organic phase according to any one of claims 4 to 7, or the method according to any one of claims 8 to 9 in nickel ore mining and waste resource recycling.

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