An extractant, its preparation method and application

Abstract

The present application provides an extractant and its preparation method and application, the extractant includes diluent and the combination of nitrogen-containing heterocyclic amide compound, the nitrogen-containing heterocyclic amide compound has as shown in formula I structure.The extractant with nitrogen-containing heterocyclic amide compound as active ingredient, especially suitable for metal separation in chloride or nitrate system, can efficiently separate manganese, magnesium, calcium and other impurities, purify nickel and cobalt.The extractant preferentially extracts nickel, separates cobalt, fills the blank of selective extraction of nickel in nickel / cobalt separation, and removes iron, copper, zinc, manganese, calcium, magnesium and other impurities by single extractant, simplifies the process.The extractant is especially suitable for being used as nickel-cobalt extractant for metal separation in nickel-cobalt feed liquid, has large extraction capacity, good separation effect, low reagent consumption, simple process, does not need acid and alkali consumption in extraction process, low operating cost, and will not bring complex waste water treatment problem, more environmental protection.

Description

Technical Field

[0001] This invention belongs to the field of chemical separation technology, specifically relating to an extractant, its preparation method, and its application. Background Technology

[0002] With the rapid development of new energy technologies, the demand for lithium batteries is increasing. Nickel-cobalt-manganese ternary cathode materials, with their good cycle performance and high cost-effectiveness, are among the commonly used cathode materials for lithium batteries. Nickel and cobalt are important elements in battery components, and their separation and extraction technologies are key research topics in the chemical industry. The development of nickel-cobalt separation technology can, on the one hand, improve the mining efficiency of low-grade nickel-cobalt ores, obtaining high-purity nickel-cobalt products and thus reducing the mining cost of low-grade nickel-cobalt ores; on the other hand, it can recycle nickel and cobalt from waste lithium battery cathode materials, realizing the recycling of metals, which is of great significance to environmental protection and sustainable resource development.

[0003] Nickel-cobalt extraction and separation are generally carried out in a sulfate system. For example, CN112430733A discloses a method for processing lateritic nickel ore, which includes the following steps: leaching lateritic nickel ore with sulfuric acid to obtain a lateritic nickel ore leachate; precipitating the lateritic nickel ore leachate to obtain a nickel-cobalt-containing solution; and subjecting the nickel-cobalt sulfate solution to impurity removal and extraction treatments to obtain battery-grade nickel sulfate and cobalt sulfate. The impurity removal extractant used in the impurity removal treatment is P204, and the extraction extractant used in the extraction treatment is CPH88. This method can achieve the synergistic recovery of nickel and cobalt. CN112941338A discloses a method for co-extraction enrichment of nickel and cobalt in a mixed solution, comprising the following steps: (1) homogeneously saponifying a P507 extractant with an alkali to obtain a saponified extractant; (2) co-extracting, settling, and separating a cobalt-nickel solution containing impurities with the saponified extractant to obtain an organic phase loaded with nickel and cobalt; (3) acid washing the organic phase with sulfuric acid to obtain an acid-washed organic phase loaded with nickel and cobalt; (4) back-extracting the acid-washed organic phase with a sulfuric acid back-extractant to obtain an aqueous phase containing nickel and cobalt. Existing nickel-cobalt extractants are mostly P204 and P507, which are acidic extractants, and the reaction with nickel and cobalt is a cation exchange process. The use of this type of extractant generally requires the addition of alkali to saponify the extractant, or the adjustment to a suitable equilibrium pH during the extraction process, resulting in high acid and alkali consumption and excessive salt content in the wastewater generated by the extraction process, which brings about wastewater treatment problems. If ammonia is used for extractant saponification or to adjust the extraction equilibrium pH, the ammonia nitrogen content in the wastewater will increase, which will also increase the wastewater treatment cost.

[0004] Another system for nickel-cobalt extraction and separation is the chloride system, which often uses amine extractants (such as N235) to form CoCl4 via Co(II). 2-Co is separated by anion exchange extraction, while Ni(II) remains unextracted. However, for solutions containing a small amount of Ni from a large amount of Co, the saturation capacity of amine extractants is relatively small. Separating Ni by completely extracting Co is labor-intensive and costly. Furthermore, nickel and cobalt often contain impurities such as iron, zinc, copper, manganese, magnesium, and calcium. Removing these impurities is necessary to extract pure nickel and cobalt. Currently, multiple extraction systems are used in multiple extraction cycles for separation and removal, resulting in a long process flow, high reagent consumption, and high costs.

[0005] Therefore, developing extractants with better separation effects and larger capacity is a key research focus in this field. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide an extractant, its preparation method, and its application. The extractant uses a nitrogen-containing heterocyclic amide compound as the active ingredient and is particularly suitable for chloride or nitrate systems. It can efficiently separate impurities such as manganese, magnesium, and calcium, and purify nickel and cobalt. It has a large extraction capacity, good separation effect, low reagent consumption, and a simple process.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides an extractant comprising a combination of a diluent and a nitrogen-containing heterocyclic amide compound having a structure as shown in Formula I:

[0009]

[0010] In Formula I, R1 is selected from any one of the nitrogen-containing heteroaryl groups of C4-C20 (e.g., C4, C5, C6, C7, C8, C9, C10, C11, C12, C14, C16 or C18, etc.).

[0011] In Formula I, R2 is selected from hydrogen, or any one of C8-C12 (e.g., C8, C9, C10, C11 or C12) straight-chain or branched alkyl groups;

[0012] In Formula I, R3 is selected from any one of C8-C12 (e.g., C8, C9, C10, C11 or C12) straight-chain or branched alkyl groups.

[0013] The extractant provided by this invention uses a nitrogen-containing heterocyclic amide compound with the structure shown in Formula I as the main active ingredient. It is used for the separation of nickel and cobalt in chloride and / or nitrate systems without acid-base adjustment. It preferentially extracts Ni(II) and separates it from Co(II). This type of extractant extracts Fe(III), Cu(II), and Zn(II) more strongly than Ni(II), and extracts almost no Mn(II), Ca(II), and Mg(II). The extractant is particularly suitable as a nickel-cobalt extractant, preferentially extracting nickel and cobalt from nickel-cobalt feed solutions and separating impurity elements such as manganese, magnesium, and calcium. The extractant has a large extraction capacity, good separation effect, and uses water back-extraction, resulting in low reagent consumption.

[0014] Preferably, R1 is selected from pyrrole. pyridyl Quinoline or isoquinoline Any one of them; the dashed line represents the connection site of the group.

[0015] Preferably, R2 is selected from any one of hydrogen, octyl, isooctyl, decyl, isodecyl, or dodecyl.

[0016] Preferably, R3 is selected from any one of octyl, isooctyl, decyl, isodecyl, or dodecyl.

[0017] Preferably, the nitrogen-containing heterocyclic amide compound includes N-octylquinoline-8-carboxamide, N-isooctylquinoline-8-carboxamide, N,N-di(octyl)quinoline-8-carboxamide, N,N-di(isooctyl)quinoline-8-carboxamide, N-octylisoquinoline-8-carboxamide, N-isooctylisoquinoline-8-carboxamide, N,N-di(octyl)isoquinoline-8-carboxamide, N,N-di(isooctyl)isoquinoline-2-carboxamide, N-dodecylquinoline-8-carboxamide, N,N-bis(octyl)quinoline-8-carboxamide, etc. (Dodecyl)quinoline-8-carboxamide, N-dodecylisoquinoline-8-carboxamide, N,N-bis(dodecyl)isoquinoline-8-carboxamide, N-octyl-1H-pyrrole-2-carboxamide, N-isooctyl-1H-pyrrole-2-carboxamide, N,N-bis(octyl)-1H-pyrrole-2-carboxamide, N,N-bis(isooctyl)-1H-pyrrole-2-carboxamide, N-dodecyl-1H-pyrrole-2-carboxamide, N,N-bis(dodecyl)-1H-pyrrole-2-carboxamide N-C(Octyl)-1H-pyrrole-3-carboxamide, N-Isooctyl-1H-pyrrole-3-carboxamide, N,N-Di(Octyl)-1H-pyrrole-3-carboxamide, N,N-Di(Isooctyl)-1H-pyrrole-3-carboxamide, N-Dodecyl-1H-pyrrole-3-carboxamide, N,N-Bis(Dodecyl)-1H-pyrrole-3-carboxamide, N-Octylpyridine-3-carboxamide, N-Isooctylpyridine-3-carboxamide, N,N-Di(Octyl)pyridine-3-carboxamide The amide, N,N-di(isooctyl)pyridine-3-carboxamide, N-octylpyridine-4-carboxamide, N-isooctylpyridine-4-carboxamide, N,N-di(octyl)pyridine-4-carboxamide, N,N-di(isooctyl)pyridine-4-carboxamide, N-dodecylpyridine-3-carboxamide, N-dodecylpyridine-4-carboxamide, N,N-bis(dodecyl)pyridine-3-carboxamide or N,N-bis(dodecyl)pyridine-4-carboxamide, any one or a combination of at least two of them.

[0018] As a preferred embodiment of the present invention, the nitrogen-containing heterocyclic amide compound having the structure shown in Formula I can be purchased commercially or prepared by an amide reaction. Exemplary preparation routes and related references for the nitrogen-containing heterocyclic amide compound are as follows:

[0019] Route 1: R2 is hydrogen.

[0020] Route 2: R2 is any one of C8-C12 straight-chain or branched alkyl groups.

[0021]

[0022] R1 and R3 have the same range of limitation as in Equation I.

[0023] The nitrogen-containing heterocyclic amide compound can also be synthesized with reference to the following literature: "Extraction of copper from acid chloride solutions by N-alkyl-and N,N-dialkyl-3-pyridinecarboxamides", Borowiak-Resterna A., Solvent Extraction and Ion Exchange, 2007, 12(3), 557-569; "Synthesis of N-(2-ethylhexyl)-pyridine-4-carboxamide and its synergistic behaviors with dinonylnaphthalene sulfonicacid for the selective extraction of nickel and cobalt", Liu W. et al., Separation and Purification Technology, 2022, 286:p.120385.

[0024] Preferably, the volume percentage of the nitrogen-containing heterocyclic amide compound in the extractant is 5-50%, for example, it can be 6%, 8%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 28%, 30%, 32%, 35%, 38%, 40%, 42%, 45%, or 48%, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range, but it is more preferably 10-40%.

[0025] Preferably, the diluent includes any one or a combination of at least two of sulfonated kerosene, kerosene, or aliphatic hydrocarbon solvent oil.

[0026] Preferably, the aliphatic hydrocarbon solvent oil includes solvent oils DT100 and / or D110.

[0027] Preferably, the extractant further includes a phase modifier.

[0028] As a preferred embodiment of the present invention, the extractant includes a phase modifier, which helps to adjust the polarity of the nitrogen-containing heterocyclic amide compound and increase the solubility of the nitrogen-containing heterocyclic amide compound in the diluent, thereby avoiding the occurrence of "three phases" during the extraction process.

[0029] Preferably, the phase modifier comprises neutral phosphate esters and / or aliphatic chain alkanols.

[0030] Preferably, the phase modifier includes any one or a combination of at least two of isooctanol, sec-octanol, dodecyl alcohol, isothietol, or tributyl phosphate.

[0031] Preferably, the volume percentage of the phase modifier in the extractant is 1-30%, for example, it can be 2%, 3%, 5%, 7%, 9%, 10%, 11%, 13%, 15%, 17%, 19%, 20%, 22%, 25% or 28%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0032] Preferably, the extractant comprises, by volume percentage: 10-40% nitrogen-containing heterocyclic amide compound, 1-30% phase modifier, and the balance being diluent.

[0033] In a second aspect, the present invention provides a method for preparing an extractant as described in the first aspect, the method comprising: mixing a nitrogen-containing heterocyclic amide compound with a diluent to obtain the extractant.

[0034] Thirdly, the present invention provides the application of the extractant as described in the first aspect in the separation, extraction or purification of metals.

[0035] Preferably, the metal comprises any one or a combination of at least two of Cu, Zn, Ni, Co, Mn, Ca, Mg, or Fe.

[0036] As a preferred embodiment of the present invention, the extractant is used for the separation, extraction, or purification of metals in chloride and / or nitrate systems, particularly suitable for chloride systems. It preferentially extracts nickel, followed by cobalt, with the extraction order being: Cu≈Zn≈Fe(III)>Ni>Co>>Mn≈Ca≈Mg. Since the technology for separating iron, copper, and zinc is relatively mature, the extractant provided by the present invention is of great significance in the separation of nickel and cobalt. As a nickel-cobalt extractant, it can effectively remove impurities such as calcium, magnesium, and manganese, purify nickel and cobalt, and achieve effective separation of nickel and cobalt through water back-extraction. It is suitable for the separation of nickel and cobalt in nickel ore leaching solutions, the removal of small amounts of nickel from cobalt, and the direct co-extraction of nickel and cobalt in ternary battery leaching solutions.

[0037] Fourthly, the present invention provides a method for separating metals from a nickel-cobalt feed solution, the method comprising: extracting the nickel-cobalt feed solution with the extractant described in the first aspect to obtain a loaded organic phase and a raffinate aqueous phase; wherein the anions in the nickel-cobalt feed solution include Cl... - and / or NO3 - .

[0038] Preferably, the anions in the nickel-cobalt solution include Cl. -That is, the nickel-cobalt feed solution is a chloride system, and the extraction and separation process is carried out using the extractant provided by this invention. The extraction and separation can be achieved through anion (MCl) x n- The process can be carried out in neutral molecular form by exchange or solvation, without the need for pH adjustment; moreover, the supported organic phase is back-extracted with water, without acid or alkali consumption, and the medium is easy to circulate (through HCl volatilization and recycling or mother liquor recycling after crystallization by temperature change).

[0039] Preferably, the nickel-cobalt leaching solution is a hydrochloric acid leaching solution of nickel ore.

[0040] Preferably, the pH value of the nickel-cobalt solution is 2-7, for example, the pH value can be 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6 or 6.5, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0041] Preferably, the concentration of anions in the nickel-cobalt solution is 2-7 mol / L, for example, it can be 2.5 mol / L, 3 mol / L, 3.5 mol / L, 4 mol / L, 4.5 mol / L, 5 mol / L, 5.5 mol / L, 6 mol / L or 6.5 mol / L, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0042] Preferably, the nickel-cobalt feed solution contains anions (Cl...) - The concentration of ) can be adjusted by adding hydrochloride (e.g., sodium chloride and / or ammonium chloride) to achieve 2-7 mol / L.

[0043] Preferably, the volume ratio (O / A) of the extractant to the nickel-cobalt solution is 1:(0.1-10), for example, it can be 1:0.2, 1:0.5, 1:0.8, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8 or 1:9, etc.

[0044] Preferably, the extraction is a multi-stage countercurrent extraction.

[0045] Preferably, the number of stages in the multi-stage countercurrent extraction is 2-10, for example, it can be 3, 4, 5, 6, 7, 8 or 9 stages.

[0046] Preferably, the supported organic phase is back-extracted with water to obtain nickel and cobalt, respectively.

[0047] Preferably, the volume ratio (O / A) of the loaded organic phase to water is (1-50):1, for example, it can be 2:1, 5:1, 8:1, 10:1, 15:1, 20:1, 25:1, 30:1, 35:1, 40:1 or 45:1, etc.

[0048] Preferably, the back-extraction is a multi-stage countercurrent back-extraction.

[0049] Preferably, the number of stages in the multi-stage countercurrent back-extraction is 2-10, for example, it can be 3, 4, 5, 6, 7, 8 or 9 stages.

[0050] Preferably, the supported organic phase further includes a washing step before back-extraction.

[0051] Preferably, the washing reagent is a hydrochloride solution and / or a nitrate solution.

[0052] Preferably, the anion in the nickel-cobalt solution is Cl. - The washing reagent is a hydrochloride (e.g., sodium chloride) solution.

[0053] Preferably, the concentration of the hydrochloric acid solution is 2-7 mol / L, for example, it can be 2.5 mol / L, 3 mol / L, 3.5 mol / L, 4 mol / L, 4.5 mol / L, 5 mol / L, 5.5 mol / L, 6 mol / L or 6.5 mol / L, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0054] Preferably, the volume ratio (O / A) of the supported organic phase to the washing reagent is (1-30):1, for example, it can be 3:1, 5:1, 7:1, 10:1, 12:1, 15:1, 17:1, 19:1, 20:1, 23:1, 25:1, 27:1 or 29:1, etc.

[0055] Preferably, the separation method includes the following steps:

[0056] (1) The nickel-cobalt feed solution is extracted using the extractant to obtain a loaded organic phase and a raffinate aqueous phase; the anions in the nickel-cobalt feed solution include Cl. - The pH value of the nickel-cobalt solution is 2-7, and the Cl content in the nickel-cobalt solution is... - The concentration is 2-7 mol / L; the volume ratio of the extractant to the nickel-cobalt solution is 1:(0.1-10);

[0057] (2) The loaded organic phase obtained in step (1) is washed with hydrochloric acid solution to obtain the washed loaded organic phase; the concentration of the hydrochloric acid solution is 2-7 mol / L; the volume ratio of the loaded organic phase to the hydrochloric acid solution during washing is (1-30):1.

[0058] (3) The washed loaded organic phase obtained in step (2) is back-extracted with water to obtain nickel and cobalt; the volume ratio of the washed loaded organic phase to water is (1-50):1.

[0059] Compared with the prior art, the present invention has the following beneficial effects:

[0060] The extractant provided by this invention uses a nitrogen-containing heterocyclic amide compound as the active ingredient, and is particularly suitable for metal separation in chloride or nitrate systems. It can efficiently separate impurities such as manganese, magnesium, and calcium, and purify nickel and cobalt. The extractant preferentially extracts nickel and separates cobalt, filling the gap in selective extraction of nickel for cobalt separation. It also removes impurities such as iron, copper, zinc, manganese, calcium, and magnesium using a single extractant, simplifying the process. The extractant is particularly suitable as a nickel-cobalt extractant for metal separation in nickel-cobalt solutions. The extraction rate of nickel and cobalt can reach over 90%, and the extraction rate of nickel can even reach 99%. It has a large extraction capacity, good separation effect, high extraction efficiency, and a phase separation time ≤15 min, which can be as low as 5 min. It has low reagent consumption, a simple process, does not require acid or alkali consumption during extraction, has low operating costs, and avoids complex wastewater treatment problems, making it more environmentally friendly. Detailed Implementation

[0061] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0062] The materials used in the following specific embodiments of the present invention are obtained through the following means:

[0063] (1) Nitrogen-containing heterocyclic amide compounds: These are obtained through commercial purchases or prepared via amide reactions. The preparation routes and relevant references for these nitrogen-containing heterocyclic amide compounds are as follows:

[0064] Route 1: R2 is hydrogen.

[0065] Route 2: R2 is any one of C8-C12 straight-chain or branched alkyl groups. R1 and R3 have the same range of limitation as in Equation I.

[0066] For example, the nitrogen-containing heterocyclic amide compound can also be synthesized with reference to the following literature: Literature 1: "Extraction of copper from acid chloride solutions by N-alkyl-and N,N-dialkyl-3-pyridinecarboxamides", Borowiak-Resterna A., Solvent Extraction and Ion Exchange, 2007, 12(3), 557-569; Literature 2: "Synthesis of N-(2-ethylhexyl)-pyridine-4-carboxamide and its synergistic behaviors with dinonylnaphthalenesulfonic acid for the selective extraction of nickel and cobalt", Liu W. et al., Separation and Purification Technology, 2022, 286:p.120385.

[0067] Specifically, the N-isooctylpyridine-4-carboxamide is obtained by reacting 4-pyridinecarboxylic acid with isooctylamine; N-octylpyridine-4-carboxamide is obtained by reacting 4-pyridinecarboxylic acid with n-octylamine; N-isooctylquinoline-8-carboxamide is obtained by reacting 8-quinolinecarboxylic acid with isooctylamine; N,N-di(isooctyl)quinoline-8-carboxamide is obtained by reacting 8-quinolinecarboxylic acid with diisooctylamine; N-octyl-1H-pyrrole-2-carboxamide is obtained by reacting pyrrole-2-carboxylic acid with n-octylamine; N-isooctyl-1H-pyrrole-2-carboxamide is obtained by reacting pyrrole-2-carboxylic acid with isooctylamine; N,N-bis(dodecyl)-1H-pyrrole-2-carboxamide is obtained by reacting pyrrole-2-carboxylic acid with bisdodecylamine; the synthesis process parameters can be found in reference 2.

[0068] (2) Phase modifiers: Tributyl phosphate (TBP) and isothietrol were purchased from Chongqing Kangpu Chemical Industry Co., Ltd.

[0069] (3) Diluent: kerosene, aliphatic hydrocarbon solvent oil DT100, purchased from Chongqing Kangpu Chemical Industry Co., Ltd.

[0070] Example 1

[0071] An extractant comprising, by volume percentage: 30% of a nitrogen-containing heterocyclic amide compound (N-isooctylpyridine-4-carboxamide), 5% of a phase modifier (tributyl phosphate, TBP), and the balance being a diluent (kerosene).

[0072] The extraction agent is prepared by mixing a nitrogen-containing heterocyclic amide compound, a phase modifier, and a diluent at room temperature to obtain the extraction agent.

[0073] Example 2

[0074] An extractant comprising, by volume percentage: 10% of a nitrogen-containing heterocyclic amide compound (N-isooctylpyridine-4-carboxamide), 1% of a phase modifier (TBP), and the balance being a diluent (kerosene).

[0075] The extraction agent is prepared by mixing a nitrogen-containing heterocyclic amide compound, a phase modifier, and a diluent at room temperature to obtain the extraction agent.

[0076] Example 3

[0077] An extractant comprising, by volume percentage: 40% nitrogen-containing heterocyclic amide compound (N-isooctylpyridine-4-carboxamide), 20% phase modifier (TBP), and the balance being diluent (kerosene).

[0078] The extraction agent is prepared by mixing a nitrogen-containing heterocyclic amide compound, a phase modifier, and a diluent at room temperature to obtain the extraction agent.

[0079] Example 4

[0080] An extractant comprising, by volume percentage: 30% of a nitrogen-containing heterocyclic amide compound (N-octylpyridine-4-carboxamide), 5% of a phase modifier (TBP), and the balance being a diluent (kerosene).

[0081] The extraction agent is prepared by mixing a nitrogen-containing heterocyclic amide compound, a phase modifier, and a diluent at room temperature to obtain the extraction agent.

[0082] Example 5

[0083] A nickel-cobalt extractant comprises, by volume percentage: 30% nitrogen-containing heterocyclic amide compound (N-isooctylquinoline-8-carboxamide), 5% phase modifier (isotridecyl alcohol), and the balance being diluent (DT100).

[0084] The extraction agent is prepared by mixing a nitrogen-containing heterocyclic amide compound, a phase modifier, and a diluent at room temperature to obtain the extraction agent.

[0085] Example 6

[0086] A nickel-cobalt extractant comprises, by volume percentage: 30% of a nitrogen-containing heterocyclic amide compound (N,N-bis(isooctyl)quinoline-8-carboxamide), 5% of a phase modifier (isotridecyl alcohol), and the balance being a diluent (DT100).

[0087] The extraction agent is prepared by mixing a nitrogen-containing heterocyclic amide compound, a phase modifier, and a diluent at room temperature to obtain the extraction agent.

[0088] Example 7

[0089] A nickel-cobalt extractant comprises, by volume percentage: 30% of a nitrogen-containing heterocyclic amide compound (N-octyl-1H-pyrrole-2-carboxamide), 5% of a phase modifier (isotridecyl alcohol), and the balance being a diluent (DT100).

[0090] The extraction agent is prepared by mixing a nitrogen-containing heterocyclic amide compound, a phase modifier, and a diluent at room temperature to obtain the extraction agent.

[0091] Example 8

[0092] A nickel-cobalt extractant comprises, by volume percentage: 30% of a nitrogen-containing heterocyclic amide compound (N-isooctyl-1H-pyrrole-2-carboxamide), 5% of a phase modifier (isotridecyl alcohol), and the balance being a diluent (DT100).

[0093] The extraction agent is prepared by mixing a nitrogen-containing heterocyclic amide compound, a phase modifier, and a diluent at room temperature to obtain the extraction agent.

[0094] Example 9

[0095] A nickel-cobalt extractant comprises, by volume percentage: 30% of a nitrogen-containing heterocyclic amide compound (N,N-bis(dodecyl)-1H-pyrrole-2-carboxamide), 5% of a phase modifier (isotridecyl alcohol), and the balance being a diluent (DT100).

[0096] The extraction agent is prepared by mixing a nitrogen-containing heterocyclic amide compound, a phase modifier, and a diluent at room temperature to obtain the extraction agent.

[0097] Application examples

[0098] A method for separating metals from a nickel-cobalt leaching solution, comprising extraction treatment using the extractants provided in Examples 1-9; the nickel-cobalt leaching solution is a hydrochloric acid leaching solution of lateritic nickel ore, with an initial pH of 4.0 and the following composition: 5.3 g / L Ni 2+ 0.52g / L Co 2+ 2.12 g / L Mn 2+ 12.15 g / L Mg 2+ 0.5g / L Ca 2+ .

[0099] The separation method specifically includes the following steps:

[0100] (1) The extractant is mixed and stirred with the nickel-cobalt feed solution, and an appropriate amount of solid sodium chloride is added to adjust the Cl. - Concentration, extraction was performed to obtain a loaded organic phase and a raffinate aqueous phase; after extraction equilibrium, the pH of the nickel-cobalt feed solution was 4, Cl - The concentration of the extractant is 6 mol / L; the volume ratio of the extractant to the nickel-cobalt feed solution (O / A) is 1:1; the extraction is a 4-stage countercurrent extraction.

[0101] (2) The loaded organic phase obtained in step (1) is washed with 6 mol / L sodium chloride solution. The volume ratio (O / A) of the loaded organic phase to the sodium chloride solution during washing is 10:1. The washing is a 3-stage countercurrent washing to obtain the washed loaded organic phase.

[0102] (3) The washed loaded organic phase obtained in step (2) is back-extracted with deionized water. The volume ratio (O / A) of the washed loaded organic phase to water in the back-extraction operation is 20:1. The back-extraction is a 3-stage countercurrent back-extraction to complete the metal separation.

[0103] Separation effect evaluation:

[0104] The concentration of metal ions in the raffinate was quantified using ICP-OES (inductively coupled plasma optical emission spectrometry); the metal ion content in the organic phase was also analyzed using ICP-OES after back-extraction with deionized water; the metal extraction rate (Ex) was calculated using the following formula:

[0105]

[0106] Among them, C org and C aq V represents the concentration of metal ions in the organic and aqueous phases, respectively. org and V aq These represent the volumes of the organic phase and the aqueous phase, respectively.

[0107] The specific test results are shown in Table 1:

[0108] Table 1

[0109]

[0110] According to the test results in Table 1, the extractant provided by this invention uses nitrogen-containing heterocyclic amide compounds as the active ingredient and exhibits good selectivity for nickel and cobalt. The extraction rates of nickel and cobalt can reach over 90%, and even 99%. Impurity ions such as manganese, calcium, and magnesium are hardly extracted. Moreover, the phase separation time is ≤15 min, or even <5 min. It has high extraction efficiency, large capacity, simple process, and does not require acid or alkali consumption during the extraction process.

[0111] According to the components of the extractants in Examples 1-9 and the test results in Table 1, the extraction of nickel and cobalt using different nitrogen-containing heterocyclic amide compounds as active ingredients also follows these rules: (1) Adding phase modifiers such as TBP or isotretinoin can effectively avoid the formation of "three phases" during the extraction process; for example, the content of phase modifier in Example 2 was relatively low, resulting in the appearance of "three phases" during phase separation. (2) In the nitrogen-containing heterocyclic amide compounds, when the carbon chain attached to the amide N is a branched chain, it has a better phase separation effect than the straight chain system. (3) The extraction rate of nickel and cobalt increases with the increase of extractant concentration, but the corresponding phase separation time also increases. In practical applications, an appropriate concentration can be selected. (4) At the same volume concentration, the extraction ability of three types of nitrogen-containing heterocyclic amide compounds with different nitrogen heterocycles (i.e., different R1) for nickel and cobalt is in the following order: pyrrolamide compounds > pyridine amide compounds > quinoline amide compounds. (5) At the same volume concentration, the extractant containing nitrogen-containing heterocyclic secondary amide compounds (i.e., R2 is hydrogen) has a significantly better extraction ability for nickel and cobalt than the extractant containing nitrogen-containing heterocyclic tertiary amide compounds (i.e., R2 is C8-C12 straight-chain or branched alkyl).

[0112] The applicant declares that the present invention is illustrated by the above embodiments to demonstrate an extractant, its preparation method, and its application. However, the present invention is not limited to the above embodiments, i.e., it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. An extractant for separating nickel and cobalt from a nickel-cobalt feed solution, characterized in that, The extractant comprises a combination of a diluent and a nitrogen-containing heterocyclic amide compound. The nitrogen-containing heterocyclic amide compound is any one or a combination of at least two of N-isooctylquinoline-8-carboxamide, N,N-bis(isooctyl)quinoline-8-carboxamide, N-octyl-1H-pyrrole-2-carboxamide, N-isooctyl-1H-pyrrole-2-carboxamide, N,N-bis(dodecyl)-1H-pyrrole-2-carboxamide, or N-isooctylpyridine-3-carboxamide.

2. The extractant according to claim 1, characterized in that, The volume percentage of nitrogen-containing heterocyclic amide compounds in the extractant is 5-50%.

3. The extractant according to claim 2, characterized in that, The volume percentage of nitrogen-containing heterocyclic amide compounds in the extractant is 10-40%.

4. The extractant according to claim 1, characterized in that, The diluent includes kerosene and / or aliphatic hydrocarbon solvent oil.

5. The extractant according to claim 1, characterized in that, The extractant also includes a phase modifier.

6. The extractant according to claim 5, characterized in that, The phase modifiers include neutral phosphate esters and / or aliphatic chain alkanols.

7. The extractant according to claim 6, characterized in that, The phase modifier includes any one or a combination of at least two of isooctanol, sec-octanol, dodecyl alcohol, isothietol, or tributyl phosphate.

8. The extractant according to claim 5, characterized in that, The volume percentage of the phase modifier in the extractant is 1-30%.

9. The extractant according to claim 5, characterized in that, The extractant comprises, by volume percentage: 10-40% nitrogen-containing heterocyclic amide compound, 1-30% phase modifier, and the remainder is diluent.

10. A method for preparing an extractant as described in any one of claims 5-9, characterized in that, The preparation method is as follows: a nitrogen-containing heterocyclic amide compound, a phase modifier, and a diluent are mixed evenly at room temperature to obtain the extractant.

11. An application of the extractant as described in any one of claims 1-9 in separating nickel and cobalt in a nickel-cobalt feed solution.

12. A method for separating nickel and cobalt from a nickel-cobalt slurry, characterized in that, The method includes: extracting a nickel-cobalt feed solution using the extractant as described in any one of claims 1-9 to obtain a loaded organic phase and a raffinate aqueous phase; the anions in the nickel-cobalt feed solution include Cl... - and / or NO3 - .

13. The method according to claim 12, characterized in that, The pH value of the nickel-cobalt solution is 2-7.

14. The method according to claim 12, characterized in that, The concentration of anions in the nickel-cobalt solution is 2-7 mol / L.

15. The method according to claim 12, characterized in that, The volume ratio of the extractant to the nickel-cobalt solution is 1:(0.1-10).

16. The method according to claim 12, characterized in that, The extraction is a multi-stage countercurrent extraction.

17. The method according to claim 16, characterized in that, The number of stages in the multi-stage countercurrent extraction is 2-10.

18. The method according to claim 12, characterized in that, The supported organic phase was back-extracted with water to obtain nickel and cobalt, respectively.

19. The method according to claim 18, characterized in that, The volume ratio of the supported organic phase to water is (1-50):

1.

20. The method according to claim 18, characterized in that, The back-extraction is a multi-stage countercurrent back-extraction.

21. The method according to claim 20, characterized in that, The number of stages in the multi-stage countercurrent back-extraction is 2-10.

22. The method according to claim 18, characterized in that, The supported organic phase also includes a washing step prior to back-extraction.

23. The method according to claim 22, characterized in that, The washing reagent is a hydrochloride solution and / or a nitrate solution.

24. The method according to claim 22, characterized in that, The volume ratio of the supported organic phase to the washing reagent is (1-30):1.

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