Process for the separation of lithium from a high-sodium lithium-containing solution

Abstract

This invention provides a method for separating lithium from a high-sodium lithium-containing solution. The method includes the following steps: (1) adsorbing the high-sodium lithium-containing solution with a lithium adsorbent at pH = 5-13 to obtain a lithium-loaded adsorbent; (2) washing the lithium-loaded adsorbent obtained in step (1) with a lithium-containing solution, wherein the lithium-containing solution has a pH = 3-13 and a sodium content of 40%. + / Li + (2) A lithium adsorbent loaded with lithium after washing is obtained by mass ratio ≤0.1; (3) The lithium adsorbent loaded with lithium after washing obtained in step (2) is desorbed by acid solution to obtain lithium-rich desorption solution. This invention achieves the following results under optimized process conditions using a lithium adsorbent with a specific structure: lithium adsorption rate ≥99.0%; desorption solution Li + Concentration 20-30 g / L and Na + / Li + ≤0.05, can be used for lithium carbonate preparation; lithium adsorbent can be reused after multiple cycles.

Description

Technical Field

[0001] This invention relates to the field of lithium resource extraction and recovery technology, specifically to a method for separating lithium from a high-sodium lithium-containing solution. Background Technology

[0002] In recent years, with the rapid development of the lithium battery industry, lithium resource extraction technology has continued to innovate. The lithium precipitation mother liquor produced during lithium carbonate production contains a considerable amount of lithium resources, and how to efficiently recover the lithium from it has become a key direction for process optimization.

[0003] Currently, precipitation is the primary method used in industrial processing of lithium precipitate mother liquor, but this method cannot effectively separate lithium from sodium. In contrast, lithium extraction processes based on adsorption separation exhibit unique advantages due to their simplicity and environmental friendliness. This process, through a basic "adsorption-washing-desorption" flow, enables the selective extraction and enrichment of lithium ions.

[0004] However, existing adsorption lithium extraction processes still face significant technical bottlenecks in practical applications. In particular, when processing solutions with a high sodium-to-lithium ratio, conventional processes struggle to achieve efficient lithium-sodium separation, resulting in insufficient purity of the final product.

[0005] To address the aforementioned issues, there is an urgent need to develop innovative processes to improve lithium recovery efficiency and product purity by optimizing the synergistic effect of adsorption materials and process flows. In particular, it is crucial to solve key technical challenges such as selective lithium extraction in high-sodium environments and efficient adsorption by adsorbents, thereby promoting the industrial application of adsorption-based lithium extraction processes. Summary of the Invention

[0006] The purpose of this invention is to provide a method for separating lithium from a high-sodium lithium-containing solution, which has a high lithium adsorption rate and can effectively separate it from sodium ions.

[0007] Therefore, according to a first aspect, the present invention provides a method for separating lithium from a high-sodium lithium-containing solution, comprising the following steps: (1) A lithium-loaded lithium adsorbent was obtained by adsorbing a high-sodium lithium-containing solution under pH conditions of 5-13. (2) Wash the lithium-loaded adsorbent obtained in step (1) with a lithium-containing solution, wherein the lithium-containing solution has a pH of 3-13 and contains Na+. + / Li + With a mass ratio ≤0.1, a lithium adsorbent loaded with lithium is obtained after washing; (3) The lithium adsorbent loaded with lithium after washing obtained in step (2) is desorbed using an acid solution to obtain a lithium-rich desorbent solution. Na in high sodium lithium-containing solution + / Li + Mass ratio ≥ 5.

[0008] Furthermore, the lithium adsorbent has any one or a combination of at least two of the structures shown in formulas Ia, Ib, and Ic: (Formula Ia), (Formula Ib), (Formula Ic), in: M is the resin matrix; A is selected from -O- and -NH-(CH2). t - and -NH(CH2) n NH-, where n is an integer from 2 to 9, and t is an integer from 0 to 9; B is either C or S=O; X is C, CH, or N; D, together with B and X, forms a saturated or unsaturated ring structure containing one or two heteroatoms, or a benzo[a] ring structure. D1 is a compound containing 1-3 six-membered aromatic rings with a hydroxyl group at the C=O ortho position, and 0-2 nitrogen atoms in the rings; D2 is a compound containing 1-3 six-membered aromatic rings with a hydroxyl group at the ortho position of SO2, and 0-2 nitrogen atoms in the rings; The ring structure or benzo[a] ring structure is optionally composed of one or more elements selected from C1-C2. 20 Alkyl, C1-C 20 Alkoxy, C6-C 12 Aryl, optional C1-C 20 The substituted amino, hydroxyl, fluorine and chlorine atoms are substituted, the heteroatoms are selected from N, O and S, the ring structure is a 5 or 7-membered ring structure, or the heteroatoms are selected from O, and the ring structure is a 6-membered ring structure. The hydrogen atoms on the six-membered aromatic ring, other than the phenolic hydroxyl hydrogen, are optionally separated by one or more atoms selected from C1-C2. 20 Alkyl, C1-C 20 Alkoxy, C6-C 12 Aryl, optional C1-C 20 Substitution of amino, hydroxyl, fluorine and chlorine atoms by substituted groups.

[0009] The method of this invention has a high lithium adsorption rate and a good separation effect between lithium and sodium. Detailed Implementation

[0010] The various aspects of the invention, as well as further objects, features and advantages, will be described in more detail below.

[0011] According to a first aspect, the present invention provides a method for separating lithium from a high-sodium lithium-containing solution, comprising the following steps: (1) A lithium-loaded lithium adsorbent was obtained by adsorbing a high-sodium lithium-containing solution under pH conditions of 5-13. (2) Wash the lithium-loaded adsorbent obtained in step (1) with a lithium-containing solution, wherein the lithium-containing solution has a pH of 3-13 and contains Na+. + / Li + With a mass ratio ≤0.1, a lithium adsorbent loaded with lithium is obtained after washing; (3) The lithium adsorbent loaded with lithium after washing obtained in step (2) is desorbed using an acid solution to obtain a lithium-rich desorbent solution. Na in high sodium lithium-containing solution + / Li + Mass ratio ≥ 5.

[0012] Preferably, the lithium adsorbent has any one or a combination of at least two of the structures shown in formulas Ia, Ib, and Ic: (Formula Ia), (Formula Ib), (Formula Ic), in: M is the resin matrix; A is selected from -O- and -NH-(CH2). t - and -NH(CH2) n NH-, where n is an integer from 2 to 9, and t is an integer from 0 to 9; B is either C or S=O; X is C, CH, or N; D, together with B and X, forms a saturated or unsaturated ring structure containing one or two heteroatoms, or a benzo[a] ring structure. D1 is a compound containing 1-3 six-membered aromatic rings with a hydroxyl group at the C=O ortho position, and 0-2 nitrogen atoms in the rings; D2 is a compound containing 1-3 six-membered aromatic rings with a hydroxyl group at the ortho position of SO2, and 0-2 nitrogen atoms in the rings; The ring structure or benzo[a] ring structure is optionally composed of one or more elements selected from C1-C2. 20 Alkyl, C1-C 20 Alkoxy, C6-C 12 Aryl, optional C1-C 20 The substituted amino, hydroxyl, fluorine and chlorine atoms are substituted, the heteroatoms are selected from N, O and S, the ring structure is a 5 or 7-membered ring structure, or the heteroatoms are selected from O, and the ring structure is a 6-membered ring structure. The hydrogen atoms on the six-membered aromatic ring, other than the phenolic hydroxyl hydrogen, are optionally separated by one or more atoms selected from C1-C2. 20 Alkyl, C1-C 20 Alkoxy, C6-C 12Aryl, optional C1-C 20 Substitution of amino, hydroxyl, fluorine and chlorine atoms by substituted groups.

[0013] The present invention does not specifically limit the resin matrix M. Preferably, the resin matrix M is selected from polystyrene resin, copolymer of styrene and divinylbenzene, phenolic resin, polyacrylic acid resin, and silicone resin. More preferably, the resin matrix M is selected from polystyrene resin and copolymer of styrene and divinylbenzene.

[0014] Preferably, the cyclic structure or benzocyclic structure is optionally substituted with one or two groups selected from C1-C8 alkyl, C1-C8 alkoxy, phenyl, optionally C1-C8 substituted amino, hydroxyl, fluorine and chlorine atoms.

[0015] Preferably, D1 is a compound containing 1-2 six-membered aromatic rings with a hydroxyl group at the C=O ortho position, and the number of nitrogen atoms in the ring is 1 or 2.

[0016] Preferably, D2 is a compound containing 1-2 hexa-membered aromatic molecules with a hydroxyl group at the ortho position of SO2. The number of nitrogen atoms in the ring is 0, 1, or 2.

[0017] Preferably, the hydrogen atoms on the six-membered aromatic ring, other than the phenolic hydroxyl hydrogen, are optionally substituted by one or two groups selected from C1-C8 alkyl, C1-C8 alkoxy, phenyl, optionally C1-C8 substituted amino, hydroxyl, fluorine and chlorine atoms.

[0018] Specifically, n is 2, 3, 4, 5, 6, 7, 8 or 9, and t is 1, 2, 3, 4, 5, 6, 7, 8 or 9, preferably n is 2 and t is 0, 1 or 2.

[0019] Preferably, D, B, and X form the structure shown below: , , , , , , , , , , , , , , , , and .

[0020] Preferably, D1 has the following structure: , , , , , , , , , , .

[0021] Preferably, D2 has the following structure: , , , , , , , , , , , , .

[0022] More preferably, D, B, and X form a structure as shown below: , , , and .

[0023] More preferably, D1 has the following structure: .

[0024] More preferably, D2 has the following structure: .

[0025] * indicates a connection point.

[0026] Preferably, the lithium adsorbent has a structure selected from the following: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , and , M is selected from polystyrene resin, copolymer of styrene and divinylbenzene, phenolic resin, polyacrylic resin and silicone resin.

[0027] More preferably, the lithium adsorbent has a structure selected from the following: , , , , , and , M is selected from polystyrene resin and copolymers of styrene and divinylbenzene.

[0028] Furthermore, the high-sodium lithium-containing solution includes any one or a combination of at least two of the following: salt lake brine, lithium precipitation mother liquor, lithium ore leachate, and lithium battery waste leachate, wherein the lithium concentration in the high-sodium lithium-containing solution is 0.2-5 g / L.

[0029] High-sodium lithium-containing solutions can be chloride-type, sulfate-type, or carbonate-type brine.

[0030] Furthermore, the sodium ion concentration in the high-sodium lithium-containing solution is 10-120 g / L.

[0031] Preferably, the adsorption flow rate in step (1) is 1-10 BV / h, more preferably 1-5 BV / h.

[0032] Preferably, a transformation treatment step is included before step (1), wherein the transformation treatment uses one or a combination of two of the following: a sodium hydroxide solution and a sodium carbonate solution with a concentration of 0.1-1 mol / L.

[0033] Preferably, the adsorption temperature in step (1) is 5-80℃, more preferably 10-80℃, and even more preferably 10-50℃.

[0034] Preferably, in step (1), a lithium adsorbent is used to adsorb the high sodium lithium-containing solution under conditions of pH=7-13, more preferably pH=9-12, to obtain a lithium adsorbent loaded with lithium.

[0035] Further, the lithium-containing solution in step (2) includes one or more of lithium sulfate, lithium chloride, lithium carbonate, lithium hydroxide, lithium nitrate, the washing liquid obtained in step (2), and the desorption liquid obtained in step (3); preferably, the lithium-containing solution in step (2) is one or more of lithium sulfate, lithium chloride, lithium carbonate, lithium hydroxide, and lithium nitrate solutions.

[0036] Preferably, the concentration of lithium ions in the lithium-containing solution in step (2) is 2-25 g / L.

[0037] Preferably, the content of impurity ions in the lithium-containing solution in step (2) satisfies the following ratio: Na + / Li + The mass ratio is ≤0.05, more preferably ≤0.01.

[0038] Optionally, the content of impurity ions in the lithium-containing solution also satisfies the following proportional relationship: K + / Li + Mass ratio ≤0.01, preferably ≤0.005, Ca 2+ / Li + ≤0.005.

[0039] Preferably, the lithium-containing solution in step (2) has a pH of 5-13, and more preferably a pH of 5-12.

[0040] Preferably, the washing flow rate is 0.5-10 BV / h, more preferably 1-5 BV / h.

[0041] Preferably, the amount of lithium-containing solution used in step (2) is 1-10 BV.

[0042] Further, the acid solution in step (3) includes one or a mixture of two of hydrochloric acid and sulfuric acid solutions. Preferably, the acid solution in step (3) includes a sulfuric acid solution.

[0043] Preferably, the concentration of the sulfuric acid solution is 0.5-6 mol / L and the concentration of the hydrochloric acid solution is 1-8 mol / L; more preferably, the concentration of the sulfuric acid solution is 2-6 mol / L and the concentration of the hydrochloric acid solution is 2-8 mol / L.

[0044] Preferably, the desorption flow rate is 0.5-10 BV / h, more preferably 1-5 BV / h.

[0045] Preferably, the amount of acid solution used in step (3) is 1-10 BV, more preferably 1-5 BV.

[0046] Furthermore, after desorption is completed, the lithium adsorbent after desorption is regenerated using a regenerating agent. Preferably, the regenerating agent includes one or more of pure water, tap water, industrial fresh water, and top feed effluent, and the regeneration flow rate is 1-10 BV / h.

[0047] According to a second aspect, the present invention provides a method for preparing the above-mentioned lithium adsorbent, characterized in that it includes one of the following steps S1, S2, S3, S4, and S5: S1. A resin containing a primary amine group is reacted with a compound of formula IIa, IIb, or IIc in the presence of 4-dimethylaminopyridine at a temperature of 60-120°C in a solvent selected from one or more solvents chosen from methanol, ethanol, diethyl ether, toluene, dioxane, N,N-dimethylformamide, dichloromethane, and ethyl acetate for 2-48 h via an amine-ester exchange reaction to obtain the lithium adsorbent. The molar ratio of the primary amine group, the compound of formula IIa, IIb, or IIc, to 4-dimethylaminopyridine is 1:(1-1.5):(0.1-0.5), and the amount of solvent used is 1-30 times the mass of the resin. (Formula IIa) (Formula IIa) (Formula IIb) in: Y is C1-C 10 alkoxy groups; S2. In the presence of formaldehyde, a primary amine resin is reacted with a ketone of formula IIIa, IIIb, or IIIc in an acidic solution of one or more of sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, and perchloric acid at a temperature of 40-120°C for 4-48 h to obtain the lithium adsorbent. The solvent in the acidic solution is one or a mixture of water, ethanol, methanol, and N,N-dimethylformamide. The concentration of the acidic solution is 0.1-6 mol / L. The molar ratio of the acid in the acidic solution to the primary amine groups in the resin is 0.5-3:1. The molar ratio of the primary amine groups, aldehydes, and ketones of formula IIIa, IIIb, or IIIc is 1:1-1.5:0.75-1.75, preferably 1:1-1.25:0.8-1.5. The amount of solvent in the acidic solution is 1-30 times the mass of the resin. (Formula IIIa) (Formula IIIa) (Formula IIIb) S3. First, H2N-(CH2)n-NH2 undergoes an amine-ester exchange reaction with a compound of formula IIa, IIb, or IIc to obtain an intermediate of formula IVa, IVb, or IVc. Then, a substitution reaction is carried out between the chlorinated spherical resin and the intermediate of formula IVa, IVb, or IVc in a 0.1-5 mol / L alkaline solution at a temperature of 40-120°C for 4-48 h to obtain the lithium adsorbent, H2N-(CH2). n The molar ratio of -NH2 to the compound of formula II is 1.1-1.5:1, the molar ratio of the chlorinated resin to substances of formula IVa, IVb or IVc is 1:(1.2-3), the solute of the alkaline solution is one or a combination of two or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, ammonia, triethylamine and calcium hydroxide, the solvent of the alkaline solution is one or a combination of two or more of water, ethanol, methanol, N,N-dimethylformamide, and the amount of solvent used in the alkaline solution is 1-30 times the mass of the resin.

[0048] (Formula IVa) (Formula IVb) (Formula IVc) in: n is as defined for Equation I. S4. Swell chlorine beads for 6-12 hours using any one of acetone, ethanol, 1,4-dioxane, dichloromethane, dimethyl sulfoxide, N,N-dimethylformamide, benzene, or diethyl ether. Add any one of 1-4 mol / L (preferably 2-3 mol / L) sodium hydroxide solution or potassium hydroxide solution to a reaction vessel containing the swollen chlorine bead resin. Heat at 40-90°C for 8-24 hours to hydrolyze the resin. After the reaction, separate the resin and wash it multiple times with any one or a mixture of anhydrous ethanol, dichloromethane, methanol, n-hexane, deionized water, 1,4-dioxane, or acetone to obtain the hydrolyzed chlorine beads. Place the hydrolyzed chlorine bead resin in a reaction vessel and add a solvent to swell the chlorine bead resin, a compound of formula IIa, IIb, or IIc, an acid-binding agent, and a co-catalyst. Heat at 60-10°C for 60-12 hours. The reaction is carried out at 0°C for 8-24 hours to obtain the lithium adsorbent, wherein the compound of formula IIa, IIb or IIc is as defined in step S1, the acid-binding agent is any one of potassium carbonate, sodium carbonate, triethylamine, tri-n-propylamine, and N,N-diisopropylethylamine, the co-catalyst includes potassium iodide and / or tetrabutylammonium chloride, and the molar ratio of the chlorinated resin, the compound of formula IIa, IIb or IIc and the acid-binding agent is 1:(1.5-3):(1-2), preferably 1:2:1.5. S5. The resin containing primary amine groups is mixed with a compound of formula Va, Vb, or Vc in an alkaline solution under heating conditions at a molar ratio of 1:0.75-1.75, preferably 1:0.8-1.5, to undergo a substitution reaction to obtain the lithium adsorbent. The substitution reaction conditions are as described in step S3, and the molar ratio of the solute in the alkaline solution to the primary amine groups in the resin is 0.8-2.5:1. in: (Equation Va) (Formula Vb) (Formula Vc) in: Y is either Cl or Br; q is an integer from 1 to 9, preferably q is 0, 1 or 2; D, B, and X are as defined with respect to equation Ia; D1 is defined as in equation Ib, and D2 is defined as in equation Ic; Before steps S1, S2, S3, S4, and S5, the resin matrix can be pretreated.

[0049] Specifically, the pretreatment includes rinsing the resin matrix with a solvent, stirring and shaking the resin, and then removing excess solvent.

[0050] Preferably, the solvent used in the pretreatment is a mixture of one or more solvents selected from water, ethanol, diethyl ether, toluene, dioxane, N,N-dimethylformamide, dichloromethane, and ethyl acetate.

[0051] The "chloro-2-methyl resin" mentioned in this application refers to a resin containing a chloromethyl (-CH2Cl) functional group.

[0052] Preferably, the resin matrix is ​​a macroporous resin.

[0053] As used herein, the pore size of the macroporous resin is in the range of 10-1000 nm, preferably 20-100 nm.

[0054] In this article, BV represents the resin bed volume.

[0055] This invention achieves, under optimized process conditions, a lithium adsorbent with a specific structure: a lithium adsorption rate ≥99.0%; and a desorption solution Li + Concentration 20-30 g / L and Na + / Li + ≤0.05, can be used for lithium carbonate preparation; lithium adsorbent can be reused after multiple cycles.

[0056] In this application, the terms "comprising" and "including" cover situations where other elements not explicitly mentioned are also included, as well as situations where the mentioned elements constitute the entirety of the application.

[0057] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In the event of any discrepancy between the definitions of terms in this specification and their commonly understood meaning by one of ordinary skill in the art to which this invention pertains, the definitions set forth herein shall prevail.

[0058] Unless otherwise stated, all numerical values ​​for the amount of ingredients, temperature, time, etc., used in the specification and claims are to be understood as being modified by the term "about". Therefore, unless otherwise indicated, the numerical parameters set forth herein are approximate values ​​that can be varied to obtain the desired performance.

[0059] Example The following will further illustrate the concept and technical effects of the present invention with reference to embodiments, so that those skilled in the art can fully understand the purpose, features, and effects of the present invention. It will be readily understood by those skilled in the art that the embodiments described herein are merely illustrative, and the scope of the present invention is not limited thereto.

[0060] Synthesis Example 1: Preparation of Resin 1 The synthetic route for resin 1 is shown below: (Resin 1) Add 10 g (30 mmol, -NH2) of primary amine polystyrene resin (from Samsung Resins, model SX382) and 7.18 g (35 mmol) of... to a three-necked flask. (CAS No.: 43015-71-0) 0.48 g (4 mmol) of 4-dimethylaminopyridine, and then 50 mL of N,N-dimethylformamide were added. The mixture was heated at 100 °C for 12 hours under mechanical stirring. After the reaction was completed, the resin was separated and washed repeatedly with anhydrous ethanol and acetone to obtain resin 1.

[0061] Synthesis Example 2: Preparation of Resin 2 The synthetic route for resin 2 is shown below: (Resin 2) 10 g (30 mmol, -NH2) of primary amine polystyrene resin (from Samsung Resin, model SX382), 5.5 g (35 mmol) of methyl 2,4-dioxapyrrolidine-3-carboxylate, and 0.48 g (4 mmol) of 4-dimethylaminopyridine were added to a three-necked flask, followed by 50 mL of toluene. The mixture was heated at 80 °C for 24 hours under mechanical stirring. After the reaction was completed, the resin was separated and washed repeatedly with anhydrous ethanol and acetone to obtain resin 2.

[0062] Synthesis Example 3: Preparation of Resin 3 The synthetic route for resin 3 is shown below: (Resin 3) Specifically, 10 g (30 mmol, -NH2) and 8.5 g (45 mmol) of primary amino polystyrene microspheres (from Samsung Resin, model SX382) were taken. (CAS No.: 185746-06-9) was placed in a 100ml three-necked flask, and 57g of acetone and 4.6g (45mmol) of triethylamine were added in sequence. The mixture was heated to 60℃ under mechanical stirring and reacted for 4 hours. After the reaction was completed, the resin was separated and washed repeatedly with anhydrous ethanol and acetone to obtain resin 3.

[0063] Synthesis Example 4: Preparation of Resin 4 The synthetic route for resin 4 is shown below: (Resin 4) Add 10g (30mmol, -NH2) primary amine polystyrene resin (from Samsung Resins, model SX382) and 8.2g (35mmol) of [unclear text - likely a continuation of the previous sentence] to a three-necked flask. (CAS No.: 1084-41-9) 0.48 g (4 mmol) of 4-dimethylaminopyridine, and then 100 mL of N,N-dimethylformamide were added. The mixture was heated at 100 °C for 12 hours under mechanical stirring. After the reaction was completed, the resin was separated and washed repeatedly with anhydrous ethanol and acetone to obtain resin 4.

[0064] Synthesis Example 5: Preparation of Resin 5 The synthetic route for resin 5 is shown below: (Resin 5) 10 g (30 mmol, -NH2) of primary amine polystyrene resin (from Samsung Resin, model SX382), 6.0 g (35 mmol) of ethyl 4-hydroxy-2-oxo-2,5-dihydro-3-furanose, and 0.48 g (4 mmol) of 4-dimethylaminopyridine were added to a three-necked flask, followed by 100 mL of N,N-dimethylformamide. The mixture was heated at 100 °C for 12 hours under mechanical stirring. After the reaction was completed, the resin was separated and washed repeatedly with anhydrous ethanol and acetone to obtain resin 5.

[0065] Synthesis Example 6: Preparation of Resin 6 The synthetic route for resin 6 is shown below: (Resin 6) 10 g (30 mmol, -NH2) of primary amine polystyrene resin (from Samsung Resin, model SX382), 5.4 g (35 mmol) of methyl 4-hydroxy-5-pyrimidinecarboxylate, and 0.48 g (4 mmol) of 4-dimethylaminopyridine were added to a three-necked flask. Then, 100 mL of N,N-dimethylformamide was added. The mixture was heated at 100 °C for 12 hours under mechanical stirring. After the reaction was completed, the resin was separated and washed repeatedly with anhydrous ethanol and acetone to obtain resin 6.

[0066] Synthesis Example 7: Preparation of Resin 7 The synthetic route for resin 7 is shown below: (Resin 7) Specifically, 10 g (30 mmol, -NH2) and 9.3 g (45 mmol) of primary amino polystyrene microspheres (from Samsung Resin, model SX382) were taken. (CAS No.: 219715-44-3) was placed in a 100ml three-necked flask, and 57g of acetone and 4.6g (45mmol) of triethylamine were added in sequence. The mixture was heated to 60℃ under mechanical stirring and reacted for 4 hours. After the reaction was completed, the resin was separated and boiled at 50℃ for 12 hours with 2 mol / L NaOH solution. Then it was washed repeatedly with anhydrous ethanol and acetone to obtain resin 7.

[0067] Example 1 This embodiment uses salt lake brine as raw material. The concentrations of lithium ions and sodium ions in the salt lake brine are 4.1 g / L and 95.3 g / L, respectively. - 95 g / L, SO4 2- 3.6 g / L, CO3 2-23 g / L, initial pH=9.5. Two resin columns packed with resin 1 (single column packing volume 1 BV=65 mL) were connected in series, and 0.6 mol / L NaOH solution (total volume 10 BV) was passed in reverse from bottom to top at a flow rate of 5 BV / h. The saponified solution was recycled until the pH of the effluent was measured three times consecutively within the range of 10.3 ± 0.3.

[0068] The modified resin columns were adjusted to a 6-column series configuration. The feed solution was introduced forward at a flow rate of 1.0 BV / h at 15°C, controlling the total feed volume to 10 BV. The first 3 BV was the adsorption tail liquid, which was directly discharged, and the remaining 7 BV was returned to the feed tank. Washing was performed using a 4-column series configuration, with a Li₂SO₄ solution (Li₂SO₄) introduced forward at a flow rate of 1 BV / h. + =25 g / L, Na + / Li + (Mass ratio = 0.01, pH = 5.0), total dosage is 3 BV.

[0069] Maintain 4 columns in series, and pass 4.0 mol / L H2SO4 solution forward at a flow rate of 1.0 BV / h. Collect the first 1.8 BV as lithium-rich desorption solution. Rinse the resin column with pure water until the outlet pH is >2, and set aside for later use.

[0070] The lithium recovery rate and the concentration of major ions in the lithium-rich desorption solution are shown in Table 1.

[0071] (Note: In this embodiment and all subsequent embodiments, 1 BV refers to a 65 mL resin bed volume.) Example 2 The raw material is a filtrate obtained by filtering the lithium precipitation mother liquor from the lithium carbonate production process. The main dissolved components are lithium chloride, lithium carbonate, sodium carbonate, and sodium chloride. The filtrate contains Li. + 3.2 g / L, Na + 70.2 g / L, CO3 2- 25 g / L, initial pH=10.5. Two resin columns containing resin 2 were connected in series, and 0.6 mol / L NaOH solution was passed in reverse at 5 BV / h, with a total volume of 10 BV. The saponified solution was recycled until the pH of the effluent was measured three times consecutively within the range of 10.3 ± 0.3.

[0072] The modified resin columns were adjusted to 6 columns in series. Lithium precipitation mother liquor was introduced forward at a flow rate of 2.0 BV / h at 30℃, with a total feed volume of 15 BV. The first 9 BV was the adsorption tail liquid, which was directly discharged, and the last 6 BV was returned to the feed pool. Four columns were maintained in series, and Li₂SO₄ solution (Li₂SO₄) was introduced forward at a flow rate of 2.5 BV / h. + 20 g / L, pH=6.5, Na+ / Li + Mass ratio = 0.01), dosage 5 BV.

[0073] Maintain two columns in series, and pass 4.5 mol / L H2SO4 solution forward at a flow rate of 1.5 BV / h. Collect the first 1.8 BV as lithium-rich desorption solution. Rinse the resin column with pure water until the outlet pH is >2, and set aside for later use.

[0074] The lithium recovery rate and the concentration of major ions in the lithium-rich desorption solution are shown in Table 1.

[0075] Example 3 Using lithium ore leaching solution as raw material, the lithium ore leaching solution contains Li + 1.0 g / L, Na + 20.5 g / L, SO4 2- 33.5 g / L, Cl - 1.2 g / L, CO3 2- 0.6 g / L, initial pH = 11.5; connect two resin columns containing resin 3 in series, and backflush 0.6 mol / L NaOH solution at 5 BV / h, for a total volume of 10 BV. Circulate the saponified solution until the pH of the effluent is within the range of 10.3 ± 0.3 for three consecutive measurements.

[0076] The modified resin columns were adjusted to 5 columns in series. Lithium ore leaching solution was introduced at 20℃ at 4.0 BV / h, with a total feed of 50 BV. The first 20 BV was collected as adsorption tailings and discharged directly, while the remaining 30 BV was returned to the raw material pool. Washing was performed using 4 columns in series, with LiOH solution (Li...) being introduced forward at 1.5 BV / h. + =6.5 g / L, Na + / Li + (Mass ratio = 0.01, pH = 10.5), dosage 5 BV; Maintain three columns in series, and pass 4.8 mol / L H2SO4 solution forward at a rate of 1.5 BV / h. Collect the first 2.5 BV as lithium-rich desorption solution. Rinse the resin column with pure water until the outlet pH is >2, and set aside for later use.

[0077] The lithium recovery rate and the concentration of major ions in the lithium-rich desorption solution are shown in Table 1.

[0078] Example 4 Using lithium battery waste leachate as raw material, the lithium battery waste leachate contains Li + 0.5 g / L, Na + 12.3 g / L, SO4 2- 28 g / L, Cl -0.5 g / L, initial pH 5.5; connect two resin columns containing resin 4 in series, and backflush 0.6 mol / L NaOH solution at 5 BV / h, for a total volume of 10 BV. The saponified solution is recycled until the pH of the effluent is measured three times consecutively within the range of 10.3 ± 0.3.

[0079] The modified resin columns were adjusted to 8 columns in series. Leachate was introduced at 40°C at a rate of 4.0 BV / h, with a total feed of 100 BV. The first 50 BV was collected as adsorption tail liquid and discharged directly, while the remaining 50 BV was returned to the feed tank. Washing was performed using 3 columns in series, with LiOH solution (Li...) being introduced forward at a rate of 2 BV / h. + Concentration 10 g / L, Na + / Li + (Mass ratio = 0.02, pH = 10.0), dosage 5 BV.

[0080] Maintain three columns in series, and pass 3.8 mol / L H2SO4 solution forward at 1.2 BV / h. Collect the first 2.5 BV as lithium-rich desorption solution. Rinse the resin column with pure water until the outlet pH is >2, and set aside for later use.

[0081] The lithium recovery rate and the concentration of major ions in the lithium-rich desorption solution are shown in Table 1.

[0082] Example 5 The steps are the same as in Example 2, except that resin 2 is replaced with resin 5.

[0083] The lithium recovery rate and the concentration of major ions in the lithium-rich desorption solution are shown in Table 1.

[0084] Example 6 The steps are the same as in Example 2, except that resin 2 is replaced with resin 6.

[0085] The lithium recovery rate and the concentration of major ions in the lithium-rich desorption solution are shown in Table 1.

[0086] Example 7 The steps are the same as in Example 2, except that resin 3 is replaced with resin 7.

[0087] The lithium recovery rate and the concentration of major ions in the lithium-rich desorption solution are shown in Table 1.

[0088] Example 8 The steps are the same as in Example 2, except that resin 2 is replaced with resin 3.

[0089] The lithium recovery rate and the concentration of major ions in the lithium-rich desorption solution are shown in Table 1.

[0090] Example 9 A 100-cycle experiment was conducted using the conditions of Example 8. The results showed that, in the 100th cycle, the desorption solution Li... + 27.7 g / L (98.6% for the first time), Na + 0.74 g / L, adsorption rate 99.18%.

[0091] Comparative Example 1 Resin 8 was prepared according to the following synthetic route: (Resin 8) 10 g of primary amine polystyrene resin (from Samsung Resin, model SX382), 4.1 g (35 mmol) of methyl acetoacetate and 0.48 g (4 mmol) of 4-dimethylaminopyridine were added to a three-necked flask, followed by 100 mL of N,N-dimethylformamide. The mixture was heated to 80 °C for 24 hours under mechanical stirring. After the reaction was completed, the resin was separated and washed repeatedly with anhydrous ethanol and acetone to obtain resin 8.

[0092] The test was conducted according to Example 2, which differs from Example 2 in that the resin has the following structural formula: M represents polystyrene microspheres, i.e., resin 8.

[0093] The lithium recovery rate and the concentration of major ions in the desorption solution are shown in Table 1.

[0094] Comparative Example 2 Resin 9 was prepared according to the following synthetic route: (Resin 9) 10 g of primary amine polystyrene resin (from Samsung Resin, model SX382), 5.0 g (35 mmol) of methyl 2-oxopyrrolidine-3-carboxylic acid and 0.48 g (4 mmol) of 4-dimethylaminopyridine were added to a three-necked flask, followed by 100 mL of N,N-dimethylformamide. The mixture was heated to 80 °C for 24 hours under mechanical stirring. After the reaction was completed, the resin was separated and washed repeatedly with anhydrous ethanol and acetone to obtain resin 9.

[0095] The test was conducted according to Example 2, which differs from Example 2 in that the resin has the following structural formula: M represents polystyrene microspheres, i.e., resin 9.

[0096] The lithium recovery rate and the concentration of major ions in the desorption solution are shown in Table 1.

[0097] Comparative Example 3 The steps are the same as in Example 2, except that the pH of the lithium mother liquor was adjusted to 13.7 using a 2 mol / L sodium hydroxide solution.

[0098] The lithium recovery rate and the concentration of major ions in the desorption solution are shown in Table 1.

[0099] The experimental data for each embodiment are summarized in the table below: Table 1 Lithium adsorption rate / % = (Lithium ion content in raw material - Lithium ion content in adsorption tail liquid) / Lithium ion content in raw material × 100%.

[0100] The lithium adsorbent of this invention in Na + / Li + In raw materials with a mass ratio ≥ 5, the following can be achieved: (1) lithium adsorption rate ≥ 99.0%; (2) lithium-rich desorption solution Na + / Li + ≤0.05; (3) The performance of lithium adsorbent decreases by ≤5% after 100 cycles.

[0101] The foregoing descriptions are merely exemplary embodiments or examples of the present invention and are not intended to limit the invention. Those skilled in the art will recognize that the present invention can be modified and varied in many ways. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention are included within the scope of the claims of this application.

Claims

1. A method for separating lithium from a high-sodium lithium-containing solution, characterized in that, Includes the following steps: (1) A lithium adsorbent was used to adsorb a high sodium lithium-containing solution under pH conditions of 5-13 to obtain a lithium adsorbent loaded with lithium. (2) Wash the lithium-loaded adsorbent obtained in step (1) with a lithium-containing solution, wherein the lithium-containing solution has a pH of 3-13 and contains Na+. + / Li + With a mass ratio ≤0.1, a lithium adsorbent loaded with lithium is obtained after washing. (3) The lithium adsorbent loaded with lithium after washing obtained in step (2) is desorbed using an acid solution to obtain a lithium-rich desorption solution. Na in high sodium lithium-containing solution + / Li + Mass ratio ≥ 5 The lithium adsorbent has any one or a combination of at least two of the structures shown in formulas Ia, Ib, and Ic: (Formula Ia), (Formula Ib), (Formula Ic), in: M is the resin matrix; A is selected from -O- and -NH-(CH2). t - and -NH(CH2) n NH-, where n is an integer from 2 to 9, and t is an integer from 0 to 9; B is either C or S=O; X is C, CH, or N; D, together with B and X, forms a saturated or unsaturated ring structure containing one or two heteroatoms, or a benzo[a] ring structure. D1 is a compound containing 1-3 six-membered aromatic rings with a hydroxyl group at the C=O ortho position, and 0-2 nitrogen atoms in the rings; D2 is a compound containing 1-3 six-membered aromatic rings with a hydroxyl group at the ortho position of SO2, and 0-2 nitrogen atoms in the rings; The ring structure is as follows: (i) A 5-membered ring, with heteroatoms selected from one or two of N, O, and S; or (ii) A 6-membered ring, with heteroatoms selected from O.

2. The method according to claim 1, characterized in that, M is selected from any one or more of polystyrene resin, copolymer of styrene and divinylbenzene, phenolic resin, polyacrylic resin, and silicone resin.

3. The method according to claim 1 or 2, characterized in that, D, B, and X form the structure shown below: , , , , , , , , , , , , , , and , D1 has the following structure: 、 、 、 、 、 、 、 、 、 、 ， D2 has the following structure: 、 、 、 、 、 、 、 、 、 、 、 、 ， * indicates a connection point.

4. The method according to claim 3, characterized in that, The lithium adsorbent has a structure selected from the following: , , , , , , , , , , , , , , , , , , , , , , , , , , , , and , M is selected from polystyrene resin, copolymer of styrene and divinylbenzene, phenolic resin, polyacrylic resin and silicone resin.

5. The method according to claim 1, characterized in that, The high-sodium lithium-containing solution includes any one or a combination of at least two of the following: salt lake brine, lithium precipitation mother liquor, lithium ore leaching solution, and lithium battery waste leaching solution, wherein the lithium concentration in the high-sodium lithium-containing solution is 0.2-5 g / L.

6. The method according to claim 1, characterized in that, The sodium ion concentration in the high sodium lithium solution is 10-120 g / L, the adsorption flow rate in step (1) is 1-10 BV / h, and the adsorption temperature is 5-80℃.

7. The method according to claim 1, characterized in that, The lithium-containing solution in step (2) includes one or more of the following: lithium sulfate solution, lithium chloride solution, lithium carbonate solution, lithium hydroxide solution, lithium nitrate solution, washing liquid obtained in step (2), and desorption liquid obtained in step (3); the washing flow rate is 0.5-10 BV / h.

8. The method according to claim 7, characterized in that, The concentration of lithium ions in the lithium-containing solution in step (2) is 2-25 g / L.

9. The method according to claim 8, characterized in that, The impurity ion content in the lithium-containing solution in step (2) satisfies the following ratio: Na + / Li + Mass ratio ≤ 0.

05.

10. The method according to claim 9, characterized in that, The impurity ion content in the lithium-containing solution in step (2) satisfies the following ratio: Na + / Li + Mass ratio ≤ 0.

01.

11. The method according to claim 1, characterized in that, The acid solution in step (3) includes one or a mixture of hydrochloric acid and sulfuric acid; the concentration of the sulfuric acid solution is 0.5-6 mol / L and the concentration of the hydrochloric acid solution is 1-8 mol / L.

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