Structure, preparation and application of lithium extraction resin

Abstract

The invention provides lithium ion selective resin containing alkoxy grafted 2-hydroxybenzophenone (or aldehyde) functional groups as well as a preparation method and application of the lithium ion selective resin. The lithium ion selective resin disclosed by the invention has very strong chemical structure stability and high lithium-sodium separation factor in a wide pH range.

Description

Technical Field

[0001] The present invention relates to the field of lithium extraction materials, and in particular to the structure, preparation and application of lithium extraction resins. More specifically, the present invention relates to the structure, preparation method and process scheme of lithium ion-specific selective ion exchange resin grafted with phenolic ketone functional groups and the extraction of lithium from aqueous solution using the resin. Background Art

[0002] The rapid development of electric vehicles has led to an increasing demand for lithium-ion batteries. As an irreplaceable chemical element for making lithium-ion batteries, lithium is becoming a strategic resource that countries around the world are competing for. The efficient extraction of lithium from ores and brines is receiving widespread attention. The development of any type of lithium ore inevitably involves the stage of extracting lithium from aqueous solutions containing alkali metals and alkaline earth metals. Therefore, the development of separation materials that have special selectivity for lithium is the key direction for efficient lithium extraction.

[0003] The main methods for extracting lithium salts from lithium-containing aqueous solutions include precipitation, adsorption, ion exchange, electrodialysis membrane, nanofiltration membrane, solvent extraction, etc. Among them, adsorption and membrane methods are widely used due to their strong selectivity, simple process and equipment, continuous operation, and easy automatic control. Most of the lithium adsorbents currently used are inorganic adsorbents, including aluminum hydroxide or lithium aluminum double hydroxide-based aluminum lithium adsorbents, manganese dioxide or lithium manganate-based manganese series lithium adsorbents, titanic acid or lithium titanate-based titanium lithium adsorbents, or manganese-titanium lithium adsorbents. In addition, the electrosorption or rocking chair battery lithium extraction system containing the above-mentioned inorganic lithium adsorption materials also shows excellent application prospects. However, when the above-mentioned inorganic materials are used to extract lithium from lithium-containing aqueous solutions, hydration, swelling and dissolution processes are inevitably involved, resulting in adsorbent dissolution or structural failure, shortening the energy efficiency and service life of the material.

[0004] Ion exchange resins with organic polymer structures have better mechanical properties, durability and acid resistance than inorganic adsorbents. However, to date, only a few pure organic polymer ion exchange resins with specific selectivity for lithium ions have been disclosed. Patent CN108421539 discloses an organic resin for separating lithium and sodium, which uses single exchange groups such as sulfonic acid, phosphoric acid, carboxylic acid or aminodicarboxylic acid chelating groups to achieve selective separation of lithium. However, due to the small lithium-sodium separation factor, it is necessary to cooperate with complex ion exchange processes and equipment, and usually requires sodium washing operations with lithium-containing solutions, and the application process is relatively complicated. Patents CN113423499 and CN102786616 disclose organic polymer lithium extraction materials grafted with crown ethers, which use the crown 4 structure to achieve specific selection of lithium, and the lithium-sodium separation factor is close to 10. SuperLig Company launched SuperLig 80 molecular imprinting lithium extraction resin [Izatt et al., Metal separations of interest to the Chinese metallurgical industry, JOURNAL OF RARE EARTHS, Vol. 28, Spec. Issue, Dec. 2010, p. 22-29. Izatt et al., Handbook of Green Chemistry: Online, 2018, pp. 219-220]. Ventura et al. reported tetrahydroxyethyl methacrylate chelating lithium extraction resin prepared by ion imprinting method [Ventura et al., Selective Recovery of Lithium from Brines, PROCEEDINGS, 43rd Workshop on Geothermal Reservoir Engineering], but when the sodium-lithium ratio is close to 20, the lithium-sodium separation factor of the resin is only 3.5.

[0005] Therefore, there is still a need to develop a reagent and method that can efficiently separate lithium from alkali metals and alkaline earth metals. Summary of the invention

[0006] In order to solve the problem of efficient separation of lithium from alkali metals and alkaline earth metals, the inventors have found through long-term experimental research that 2-hydroxybenzophenone (or aldehyde) functional groups have extremely strong chelating ability for lithium, and can achieve effective separation of lithium from alkali metals such as sodium, potassium, rubidium, cesium and alkaline earth metals such as magnesium, calcium and strontium, and have developed ion exchange resin materials containing alkoxy-grafted 2-hydroxybenzophenone (or aldehyde) functional groups. The resin disclosed in the present invention has strong chemical structure stability and high lithium-sodium separation factor in a wide pH range.

[0007] A first aspect of the present disclosure provides a lithium ion selective resin material comprising at least one 2-hydroxybenzophenone (or aldehyde) type functional group having a structure of formula (I), wherein:

[0008] R1 is hydrogen, optionally substituted C1-C4 alkyl or optionally substituted benzene, wherein the substitution is carried out by a group selected from the group consisting of C1-C4 alkyl, C1-C4 alkoxy, halogen and phenyl;

[0009]

[0010] R2, R3, R4 and R5 are each independently hydrogen, halogen, nitro, benzyloxy, C 1-4 Alkyl, C 1-4 Alkoxy or linking group, provided that at least one of R2, R3, R4 and R5 is a linking group, which connects the structure of formula (I) to the polymer backbone via a covalent bond.

[0011] A second aspect of the present disclosure provides a method for extracting lithium, comprising:

[0012] The lithium ion selective resin of the first aspect is brought into contact with a lithium-containing solution, and then the lithium ion selective resin is separated.

[0013] The third aspect of the present disclosure provides a method for preparing a lithium ion selective resin by a grafting reaction, comprising: using a halogenated polymer matrix and a lithium chelating functional monomer as raw materials, and using an ether-forming grafting reaction to covalently connect the lithium chelating functional monomer to the polymer matrix to form lithium ion selective resin balls or particles.

[0014] The fourth aspect of the present disclosure provides a method for preparing a lithium ion selective resin by copolymerization, comprising: using a lithium chelating functional monomer bonded with 4-vinylbenzyl ether as a raw material, copolymerizing with 4-vinylstyrene and divinylbenzene to prepare lithium ion selective resin beads or particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present invention, but are not intended to limit the present invention.

[0016] Figure 1 The lithium extraction resin 8P3 prepared in Example 11 is used for dynamic lithium extraction performance testing of low sodium / lithium, potassium / lithium, rubidium / lithium and cesium / lithium ratio brines.

[0017] Figure 2 The lithium extraction resin 8P3 prepared in Example 11 is used for dynamic lithium extraction performance testing of high sodium / lithium, potassium / lithium, rubidium / lithium and cesium / lithium ratio brines.

[0018] Figure 3 The cycle performance of the lithium extraction resin of Example 24 is shown.

[0019] Figure 4 The infrared spectrum of the lithium extraction resin of Example 25 is shown.

[0020] Figure 5 A micrograph of the backbone resin of Example 26 before grafting is shown.

[0021] Figure 6 A micrograph of the grafted lithium-extracted resin of Example 26 is shown. DETAILED DESCRIPTION

[0022] All publications and patents mentioned in this disclosure are hereby incorporated by reference into the present invention in their entirety. If the purposes or terms used in any publications and patents incorporated by reference conflict with the purposes or terms used in the present invention, then the purposes and terms of the present invention prevail.

[0023] The section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.

[0024] Unless otherwise specified, all technical and scientific terms used herein have the common meaning in the field to which the claimed subject matter belongs. If there are multiple definitions for a term, the definition herein shall prevail.

[0025] Except in the working examples or otherwise indicated, all numbers of quantitative qualities such as dosage stated in the specification and claims should be understood to be modified by the term "about" in all cases. It should also be understood that any numerical range listed in the application is intended to include all subranges within the range and any combination of the respective endpoints of the range or subrange, for example, integers of 1-20 include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 and 20, and also include subranges 1-3, 1-4, 1-10, 2-4, 2-10, etc.

[0026] The words "include", "contain" or "comprises" and the like used in the present disclosure mean that the elements preceding the word include the elements listed after the word and their equivalents, without excluding unrecorded elements. The terms "contain" or "includes" used herein may be open, semi-closed and closed. In other words, the term also includes "consisting essentially of" or "consisting of".

[0027] The term "optionally" in this disclosure means that the described circumstances may or may not occur.

[0028] The present invention may be implemented in other specific forms without departing from the basic attributes of the present invention. It should be understood that, without conflict, any and all embodiments of the present invention may be combined with the technical features in any other embodiment or multiple other embodiments to obtain other embodiments. The present invention includes other embodiments obtained by such combination.

[0029] The description of the present disclosure should be interpreted in accordance with the laws and principles of chemical bonding. In some cases, a hydrogen atom may be removed in order to accommodate a substituent at a given position.

[0030] The term "alkyl" in the present disclosure refers to branched and straight chain monovalent hydrocarbon groups having n carbon atoms and 2n+1 hydrogen atoms. C1-C4 alkyl refers to straight or branched chain saturated monovalent hydrocarbon groups having 1 to 4 carbon atoms, for example, methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl. In one embodiment, C1-C4 alkyl is preferably straight chain, i.e., methyl, ethyl, propyl and n-butyl.

[0031] The term "alkoxy" refers to an alkyl group as defined above connected to the parent structure via an oxygen group in the present disclosure. Typical alkyl groups include, but are not limited to, methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, isobutoxy, tert-butoxy, pentyloxy, isopentyloxy, neopentyloxy, hexyloxy, heptyloxy, octyloxy, 2-ethylhexyloxy, nonyloxy, decyloxy, dodecyloxy, hexadecyloxy, etc.

[0032] The term "nitro" in this disclosure refers to a -NO2 group.

[0033] The term "benzyloxy" in the present disclosure refers to a monovalent group PhCH2O- remaining after benzyl alcohol loses a hydrogen atom from the hydroxyl group.

[0034] The term "halo" or "halogen" in the present disclosure refers to fluorine, chlorine, bromine or iodine. In some embodiments, "halo" or "halogen" is chlorine or bromine. In other embodiments, "halo" or "halogen" is fluorine.

[0035] The present disclosure provides a lithium ion selective resin, comprising at least one 2-hydroxybenzophenone (or aldehyde) functional group having a structure of formula (I), wherein:

[0036] R1 is hydrogen, optionally substituted C1-C4 alkyl or optionally substituted benzene, wherein the substitution is carried out by a group selected from the group consisting of C1-C4 alkyl, C1-C4 alkoxy, halogen and phenyl;

[0037]

[0038] R2, R3, R4 and R5 are each independently hydrogen, halogen, nitro, benzyloxy, C 1-4 Alkyl, C 1-4 Alkoxy or linking group, provided that at least one of R2, R3, R4 and R5 is a linking group, which connects the structure of formula (I) to the polymer backbone via a covalent bond.

[0039] Optionally, R1 in the structure of formula (I) is hydrogen, methyl or benzene.

[0040] In one embodiment, one of R2 to R5 in the structure of formula (I) is a linker, and the others are all H.

[0041] In another embodiment, one of R2 to R5 in the structure of formula (I) is a nitro group. Preferably, except for the nitro group and the linking group, the rest of R2 to R5 are H.

[0042] Preferably, the linking groups in R2 to R5 connected to the polymer backbone are ether bonds, so that the molecular structure containing formula (I) is grafted onto the polymer backbone. For example, the lithium ion selective resin has a structure of one of formulas (II) to (V):

[0043]

[0044] In one embodiment, the R1 group in the structures represented by formulas (II) to (V) is hydrogen, methyl or benzene, and R2 to R4 are all H.

[0045] In another embodiment, the R1 group in the structures represented by formula (II) to (V) is hydrogen, methyl or benzene, one of R2 to R4 is nitro, and the rest are all H.

[0046] Preferably, the polymer backbone is a polymer capable of being halomethylated or halogenated.

[0047] For example, the polymer backbone is styrene-divinylbenzene copolymer, polyvinyl chloride, polyphenylene ether, polyetheretherketone, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, ethylene-propylene rubber-styrene-acrylonitrile copolymer, acrylonitrile-butyl acrylate-styrene copolymer, acrylonitrile-vinyl chloride-styrene copolymer, methyl (meth)acrylate-butadiene-styrene copolymer, or styrene-butylene copolymer.

[0048] In one embodiment, the polymer backbone of the lithium ion selective resin has a crosslinking degree of 0 to 7 wt.%.

[0049] In one embodiment, the polymer skeleton of the lithium ion selective resin has a gel structure or a macroporous structure. Preferably, the polymer skeleton is spherical. For example, the diameter of the sphere of the polymer skeleton is 0.1 to 1.5 mm, 0.2 to 1.2 mm, or 0.5 to 1.5 mm.

[0050] In one embodiment, the polymer backbone of the lithium ion selective resin is a particle. Preferably, the particle size of the polymer backbone particles is 12 to 160 meshes, for example, 15-150 meshes, 20-100 meshes or 50-100 meshes.

[0051] In one embodiment, the 2-hydroxybenzophenone (or aldehyde) functional group having the structure of formula (I) is derived from a lithium chelating functional monomer selected from the group consisting of 2,4-dihydroxybenzaldehyde, 2,4-dihydroxyacetophenone, 2,4-dihydroxypropiophenone, 2,4-dihydroxybutyrophenone, 2,4-dihydroxybenzophenone, 2,6-dihydroxybenzaldehyde, 2,6-dihydroxyacetophenone, 2,6-dihydroxypropiophenone, 2,6-dihydroxybutyrophenone, 2,6-dihydroxybenzophenone, 2,4-dihydroxy-5-nitro-benzaldehyde, 2,4-dihydroxy-5-nitro-acetophenone, 2,4-dihydroxy-5-nitro-propiophenone, 2,4-dihydroxy-5-nitro-butyrophenone, 2,4-dihydroxy-5-nitro-benzophenone, 2,4-dihydroxy-3-nitro-benzaldehyde , 2,4-dihydroxy-3-nitro-acetophenone, 2,4-dihydroxy-3-nitro-propiophenone, 2,4-dihydroxy-3-nitro-butyrophenone, 2,4-dihydroxy-3-nitro-benzophenone, 2,6-dihydroxy-3-nitro-benzaldehyde, 2,6-dihydroxy-3-nitro-acetophenone, 2,6-dihydroxy-3-nitro-propiophenone, 2,6-dihydroxy-3-nitro-butyrophenone, 2,6-dihydroxy-3-nitro-benzophenone, 2,6-dihydroxy-3-nitro-benzophenone, 2,6-dihydroxy-5-nitro-benzaldehyde, 2,6-dihydroxy-5-nitro-acetophenone, 2,6-dihydroxy-5-nitro-propiophenone, 2,6-dihydroxy-5-nitro-butyrophenone, 2,6-dihydroxy-5-nitro-benzophenone, a mixture of one or more of them, or halogenated substances of these substances. For example, the lithium chelating functional monomer is bonded to the polymer backbone through ether bonding to graft the 2-hydroxybenzophenone (or aldehyde) functional group having the structure of formula (I) onto the resin.

[0052] In one embodiment, the grafting amount of the lithium chelating functional monomer is 0.01 to 5 mmol / g resin, such as 0.1 to 1 mmol / g resin, 0.5 to 3 mmol / g resin, or 1.5 to 4.5 mmol / g resin.

[0053] In one embodiment, the lithium ion selective resin material further comprises a modification group for improving hydrophilicity. Preferably, the modification group for improving hydrophilicity comprises one or more of a sulfonic acid group, a carboxylic acid group, a phosphoric acid group, a phenolic hydroxyl group, an alcoholic hydroxyl group, an iminodiacetic acid group, a primary amine group, a secondary amine group and a quaternary ammonium group.

[0054] For example, the hydrophilicity-improving modifying group is derived from benzenesulfonic acid, benzoic acid, benzyl alcohol, acrylic acid, aminophosphoric acid, iminodiacetic acid, phenol, allyl alcohol, trimethylamine quaternary ammonium salt, triethylamine quaternary ammonium salt, triethanolamine quaternary ammonium salt, or triisopropanolamine quaternary ammonium salt.

[0055] In one embodiment, the grafting amount of the hydrophilicity-improving modifying group is 0 to 3 mmol / g resin, such as 0.1 to 1 mmol / g resin, 0.5 to 2.5 mmol / g resin.

[0056] Preferably, the lithium ion selective resin further contains a cation exchange group or an anion exchange group.

[0057] In one embodiment, the lithium ion selective resin further contains a covalently bonded neutral chelating functional group. Preferably, the neutral chelating functional group is a ketone, an ester, a phosphine oxide or a crown ether. For example, the neutral chelating functional group is ethyl benzoate, (2-hydroxybenzyl) diphenylphosphine oxide, 2,5-dihydroxyphenyl diphenylphosphine oxide, benzo-12 crown 4 or / and dibenzo-14 crown 4.

[0058] In one embodiment, the grafting amount of the neutral chelating functional group is 0-3 mmol / g resin, such as 0.1-0.5 mmol / g resin or 0.5-2.5 mmol / g resin.

[0059] Preferably, the lithium saturation exchange capacity of the lithium ion selective resin is 0.05 to 1 mmol / g resin, for example, 0.1 to 0.9 mmol / g resin.

[0060] The present disclosure also provides a method for extracting lithium, comprising contacting the lithium ion selective resin with a lithium-containing solution, and then separating the lithium ion selective resin.

[0061] The lithium ion selective resin can be used to extract lithium from a lithium-containing aqueous solution, such as neutral or alkaline salt lake brine with low magnesium and calcium content, geothermal brine, or lithium precipitation mother liquor of lithium carbonate or lithium phosphate.

[0062] For example, the pH value of the aqueous solution containing lithium ions is 5 to 13, preferably 8 to 12.5. For alkaline natural brine, it can be directly contacted with the lithium ion selective resin to load the lithium ions in the brine onto the lithium ion selective resin; for lithium-containing aqueous solution with pH <7, the pH and alkalinity can be adjusted to 8 to 13 by adding alkali metal or ammonium hydroxide, carbonate, phosphate, or borate.

[0063] The method for extracting lithium may further include: a step of regenerating the lithium ion selective resin after the lithium ion selective resin contacts the lithium-containing solution. For example, a stripping agent may be used to act on the lithium ion selective resin loaded with lithium ions, so that the lithium ions enter the stripping agent, and the lithium ion selective resin is once again capable of extracting lithium from the lithium-containing aqueous solution; the stripping agent is an aqueous solution of an acid, and the preferred acid is one or more of carbonic acid, sulfuric acid, sulfurous acid, hydrochloric acid, nitric acid and phosphoric acid.

[0064] The present disclosure also provides a method for preparing a lithium ion selective resin by grafting reaction, comprising: using a halogenated polymer matrix and a lithium chelating functional monomer as raw materials, and using an etherification grafting reaction to connect the lithium chelating functional monomer to the polymer matrix in the form of a covalent bond, thereby forming lithium ion selective resin balls or particles.

[0065] In one embodiment, the ether-forming grafting reaction is: using at least one of acetone, acetonitrile, tetrahydrofuran, N,N-dimethylformamide, and N,N-dimethylacetamide as a solvent, using at least one of lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, and cesium carbonate as a base, the molar ratio of the lithium chelating functional monomer to the halogen in the polymer matrix is ​​0.2 to 1.2, for example, 0.5 to 1.0, the molar ratio of the base to the lithium chelating functional monomer is 0.2 to 1.2, for example, 0.5 to 1.0, the amount of the solvent is 2 to 20 times the mass of the polymer matrix, for example, 2 to 5 times, the grafting reaction temperature is 40 to 120° C., for example, 40 to 90° C., and the reaction time is 2 to 72 hours, for example, 2-8 hours.

[0066] Preferably, the method for preparing the lithium ion selective resin further comprises recovering the solvent by filtering after the grafting reaction is completed, and the recovered solvent is recycled.

[0067] For example, the polymer matrix is ​​a spherical chloromethylated styrene-divinylbenzene copolymer. Preferably, the spherical chloromethylated styrene-divinylbenzene copolymer further contains a sulfonic acid group, a phosphonic acid group or a carboxylic acid group.

[0068] In one embodiment, the spherical chloromethylated styrene-divinylbenzene copolymer has a chlorine content of 5 to 30 wt%, such as 5 to 10 wt%.

[0069] In one embodiment, the crosslinking degree of the spherical chloromethylated styrene-divinylbenzene copolymer is 0 to 5%, such as 0.5 to 2%.

[0070] For example, the spherical chloromethylated styrene-divinylbenzene copolymer can be prepared by chloromethylating white styrene-divinylbenzene copolymer spheres.

[0071] In one embodiment, tetrabutylammonium chloride, tetrabutylammonium bromide or tetrabutylammonium iodide is added as a phase transfer catalyst in the ether-forming grafting reaction.

[0072] Preferably, potassium iodide is added as a catalyst in the ether-forming grafting reaction.

[0073] The present disclosure also provides a method for preparing a lithium ion selective resin by copolymerization, comprising: using a lithium chelating functional monomer bonded to 4-vinylbenzyl ether as a raw material, copolymerizing with 4-vinylstyrene and optional divinylbenzene to prepare lithium ion selective resin spheres or particles. Here, optional divinylbenzene means that divinylbenzene may be present or absent.

[0074] Preferably, the copolymerization to prepare resin spheres or particles adopts suspension polymerization. For example, the lithium chelating functional monomer bonded to 4-vinyl benzyl ether is mixed with liquid styrene, optional divinyl benzene and an initiator, and then the mixture is added dropwise to an aqueous solution containing a salt such as sodium chloride and a reinforcing dispersing aid such as polyvinyl alcohol under heating conditions, and reacted under strong stirring to obtain a spherical or granular lithium ion selective resin. The initiator can be, for example, an oil-soluble initiator azobisisobutyronitrile, azobisisoheptanenitrile, azobisisovaleronitrile, azobiscyclohexylcarbonitrile, dimethyl azobisisobutyrate or benzoyl peroxide. Preferably, the molar ratio of styrene to the lithium chelating functional monomer bonded to 4-vinyl benzyl ether is 0.2 to 3, for example 0.5 to 2. Preferably, divinyl benzene is 0 to 7% of the total weight of the lithium chelating functional monomer bonded to styrene and 4-vinyl benzyl ether. When the divinylbenzene is 0% of the total weight of the lithium chelating functional monomers bonded with styrene and 4-vinylbenzyl ether, no divinylbenzene is added in the copolymerization reaction.

[0075] The 4-vinylbenzyl ether-bonded lithium chelating functional monomer can be prepared by reacting the lithium chelating functional monomer of the following formula (VI) with 4-vinylbenzyl chloride to generate an ether.

[0076]

[0077] R1 is hydrogen, optionally substituted C1-C4 alkyl or optionally substituted benzene, wherein the substitution is carried out by a group selected from the group consisting of C1-C4 alkyl, C1-C4 alkoxy, halogen and phenyl;

[0078] R2, R3, R4 and R5 are each independently hydroxy, hydrogen, halogen, nitro, benzyloxy, C 1-4 Alkyl or C 1-4 Alkoxy, provided that at least one of R2, R3, R4 and R5 is hydroxy. For example, R3 or R5 is hydroxy.

[0079] Exemplary lithium chelating functional monomers of formula (VI) may include: 2,4-dihydroxybenzaldehyde, 2,4-dihydroxyacetophenone, 2,4-dihydroxypropiophenone, 2,4-dihydroxybutyrophenone, 2,4-dihydroxybenzophenone, 2,6-dihydroxybenzaldehyde, 2,6-dihydroxyacetophenone, 2,6-dihydroxypropiophenone, 2,6-dihydroxybutyrophenone, 2,6-dihydroxybenzophenone, 2,4-dihydroxy-5-nitro-benzaldehyde, 2,4-dihydroxy-5-nitro-acetophenone, 2,4-dihydroxy-5-nitro-propiophenone, 2,4-dihydroxy-5-nitro-butyrophenone, 2,4-dihydroxy-5-nitro-benzophenone, 2,4-dihydroxy-3-nitro-benzaldehyde, 2,4-dihydroxy- 3-nitro-acetophenone, 2,4-dihydroxy-3-nitro-propiophenone, 2,4-dihydroxy-3-nitro-butyrophenone, 2,4-dihydroxy-3-nitro-benzophenone, 2,6-dihydroxy-3-nitro-benzaldehyde, 2,6-dihydroxy-3-nitro-acetophenone, 2,6-dihydroxy-3-nitro-propiophenone, 2,6-dihydroxy-3-nitro-butyrophenone, 2,6-dihydroxy-3-nitro-benzophenone, 2,6-dihydroxy-3-nitro-benzophenone, 2,6-dihydroxy-3-nitro-benzophenone, 2,6-dihydroxy-3-nitro-benzophenone, 2,6-dihydroxy-5-nitro-benzaldehyde, 2,6-dihydroxy-5-nitro-acetophenone, 2,6-dihydroxy-5-nitro-propiophenone, 2,6-dihydroxy-5-nitro-butyrophenone, 2,6-dihydroxy-5-nitro-benzophenone. A mixture of one or more of the following.

[0080] The lithium chelating functional monomer of formula (VI) reacts with 4-vinylbenzyl chloride to form an ether, for example, in the presence of one or more of a base such as lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, and cesium carbonate.

[0081] In one embodiment, the copolymerization reaction further comprises adding a monomer for improving the hydrophilicity of the lithium ion selective resin to copolymerize with the lithium chelating functional monomer bonded to 4-vinylbenzyl ether, styrene and optional divinylbenzene. Preferably, the monomer for improving the hydrophilicity of the lithium ion selective resin added in the copolymerization method for preparing the lithium ion selective resin is 0 to 3 mmol / g resin, such as 0.1 to 1 mmol / g resin, 0.5 to 2.5 mmol / g resin.

[0082] The monomer for improving the hydrophilicity of the lithium ion selective resin may contain a modifying group for improving the hydrophilicity, such as one or more of a sulfonic acid group, a carboxylic acid group, a phosphoric acid group, a phenolic hydroxyl group, an alcoholic hydroxyl group, an iminodiacetic acid group, a primary amine group, a secondary amine group and a quaternary ammonium group.

[0083] For example, examples of the monomer for improving the hydrophilicity of the lithium ion selective resin may include 4-vinylbenzenesulfonic acid (sodium), 4-vinylbenzoic acid (sodium), (4-vinylbenzyl)trimethylammonium chloride, or 4-vinylbenzyl alcohol.

[0084] In one embodiment, the copolymerization reaction further comprises adding 4-vinylbenzenesulfonic acid (sodium), (4-vinylbenzyl)trimethylammonium chloride or 4-vinylbenzyl alcohol and 4-vinylbenzyl ether bonded lithium chelating functional monomers, styrene and divinylbenzene to improve the hydrophilicity of the lithium ion selective resin.

[0085] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the specific embodiments of the present invention are clearly and completely described below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention. Based on the described embodiments of the present invention, all other implementations obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0086] If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the field or the product instructions are used. If no manufacturer is specified for the reagents or instruments used, they are all commercially available conventional products.

[0087] Unless otherwise defined, technical or scientific terms used in the following embodiments should have the common meanings understood by persons having ordinary skills in the field to which the present invention belongs.

[0088] Example 1

[0089] Using chloromethylated styrene-divinylbenzene copolymer intermediate as polymer skeleton to graft 2,4-dihydroxybenzophenone: 20g of dried spherical chloromethylated styrene-divinylbenzene copolymer intermediate (<30 mesh, divinylbenzene content of 0.5%, chlorine content of 20wt%) was added to a 250mL spherical reaction bottle, 120mL of N,N-dimethylformamide (DMF) was added, and the mixture was stirred and swollen at room temperature for 2 hours, and then 90mmol of 2,4-dihydroxybenzophenone, 100mmol of potassium carbonate, and 0.5g of potassium iodide were added, and the mixture was heated to 90°C and stirred for 16 hours. After the reaction was completed, the mixture was naturally cooled to room temperature, the DMF mother liquor was filtered out, and the resin balls were washed with 0.1M dilute sulfuric acid for multiple times, and then washed with 0.3M sodium hydroxide solution for multiple times to obtain 62g of wet lithium extraction resin, and the resin moisture content was 33wt.%, which was recorded as lithium extraction resin 1.

[0090] Example 2

[0091] Using chloromethylated styrene-divinylbenzene copolymer intermediate as polymer skeleton to graft 2,4-dihydroxy-5-nitro-benzophenone: 20g of dried spherical chloromethylated styrene-divinylbenzene copolymer intermediate (<30 mesh, divinylbenzene content of 0.5%, chlorine content of 20wt%) was added to a 250mL spherical reaction bottle, 120mL of N,N-dimethylformamide (DMF) was added, and the mixture was stirred and swollen at room temperature for 2 hours, and then 90mmol of 2,4-dihydroxy-5-nitro-benzophenone, 100mmol of potassium carbonate, and 0.5g of potassium iodide were added, and the mixture was heated to 90°C and stirred for 16 hours. After the reaction was completed, the mixture was naturally cooled to room temperature, the DMF mother liquor was filtered out, and the resin balls were washed with 0.1M dilute sulfuric acid for multiple times, and then washed with 0.3M sodium hydroxide solution for multiple times to obtain 69g of wet lithium extraction resin, and the resin moisture content was 34wt.%, which was recorded as lithium extraction resin 2.

[0092] Example 3

[0093] Using chloromethylated styrene-divinylbenzene copolymer intermediate as polymer skeleton to graft 2,4-dihydroxyacetophenone: 20g of dried spherical chloromethylated styrene-divinylbenzene copolymer intermediate (<30 mesh, divinylbenzene content of 0.5%, chlorine content of 20wt%) was added to a 250mL spherical reaction bottle, 120mL of N,N-dimethylformamide (DMF) was added, and the mixture was stirred and swollen at room temperature for 2 hours, and then 90mmol of 2,4-dihydroxyacetophenone, 100mmol of potassium carbonate, and 0.5g of potassium iodide were added, and the mixture was heated to 90°C and stirred for 16 hours. After the reaction was completed, the mixture was naturally cooled to room temperature, the DMF mother liquor was filtered out, and the resin balls were washed with 0.1M dilute sulfuric acid for multiple times, and then washed with 0.3M sodium hydroxide solution for multiple times to obtain 55g of wet lithium extraction resin, and the resin moisture content was 33wt.%, which was recorded as lithium extraction resin 3.

[0094] Example 4

[0095] Using chloromethylated styrene-divinylbenzene copolymer intermediate as polymer skeleton to graft 2,4-dihydroxy-5-nitro-acetophenone: 20g of dried spherical chloromethylated styrene-divinylbenzene copolymer intermediate (<30 mesh, divinylbenzene content of 0.5%, chlorine content of 20wt%) was added to a 250mL spherical reaction bottle, 120mL of N,N-dimethylformamide (DMF) was added, and the mixture was stirred and swollen at room temperature for 2 hours, and then 90mmol of 2,4-dihydroxy-5-nitro-acetophenone, 100mmol of potassium carbonate, and 0.5g of potassium iodide were added, and the mixture was heated to 90°C and stirred for 16 hours. After the reaction was completed, the mixture was naturally cooled to room temperature, the DMF mother liquor was filtered out, and the resin balls were washed with 0.1M dilute sulfuric acid for multiple times, and then washed with 0.3M sodium hydroxide solution for multiple times to obtain 67g of wet lithium extraction resin, and the resin moisture content was 34wt.%, which was recorded as lithium extraction resin 4.

[0096] Example 5

[0097] Using chloromethylated styrene-divinylbenzene copolymer intermediate as polymer skeleton to graft 2,4-dihydroxy-5-nitro-acetophenone: 20g of dried spherical chloromethylated styrene-divinylbenzene copolymer intermediate (<14 mesh, divinylbenzene content of 2%, chlorine content of 15wt%) was added to a 250mL spherical reaction bottle, 120mL of N,N-dimethylformamide (DMF) was added, and the mixture was stirred and swollen at room temperature for 2 hours, and then 70mmol of 2,4-dihydroxy-5-nitro-acetophenone, 80mmol of potassium carbonate, and 0.5g of potassium iodide were added, and the mixture was heated to 70°C and stirred for 16 hours. After the reaction was completed, the mixture was naturally cooled to room temperature, the DMF mother liquor was filtered out, and the resin balls were washed with 0.1M dilute sulfuric acid for multiple times, and then washed with 0.3M sodium hydroxide solution for multiple times to obtain 49g of wet lithium extraction resin, and the resin moisture content was 28wt.%, which was recorded as lithium extraction resin 5.

[0098] Example 6

[0099] Using chloromethylated styrene-divinylbenzene copolymer intermediate as polymer skeleton to graft 2,4-dihydroxy-5-nitro-acetophenone: 20g of dried spherical chloromethylated styrene-divinylbenzene copolymer intermediate (<14 mesh, divinylbenzene content of 5%, chlorine content of 15wt%) was added to a 250mL spherical reaction bottle, 120mL of N,N-dimethylformamide (DMF) was added, and the mixture was stirred at room temperature for 2 hours, and then 70mmol of 2,4-dihydroxy-5-nitro-acetophenone, 80mmol of potassium carbonate, and 0.5g of potassium iodide were added, and the mixture was heated to 70°C and stirred for 16 hours. After the reaction was completed, the mixture was naturally cooled to room temperature, the DMF mother liquor was filtered out, and the resin balls were washed with 0.1M dilute sulfuric acid for multiple times, and then washed with 0.3M sodium hydroxide solution for multiple times to obtain 44g of wet lithium extraction resin, and the resin moisture content was 19wt.%, which was recorded as lithium extraction resin 6.

[0100] Example 7

[0101] Using chloromethylated styrene-divinylbenzene copolymer intermediate as polymer skeleton to graft 2,4-dihydroxy-5-nitro-acetophenone: 20g of dried spherical chloromethylated styrene-divinylbenzene copolymer intermediate (<100 mesh, divinylbenzene content of 0.5%, chlorine content of 20wt%) was added to a 250mL spherical reaction bottle, 120mL of N,N-dimethylformamide (DMF) was added, and the mixture was stirred and swollen at room temperature for 2 hours, and then 90mmol of 2,4-dihydroxy-5-nitro-acetophenone, 100mmol of potassium carbonate, and 0.5g of potassium iodide were added, and the mixture was heated to 90°C and stirred for 16 hours. After the reaction was completed, the mixture was naturally cooled to room temperature, the DMF mother liquor was filtered out, and the resin balls were washed with 0.1M dilute sulfuric acid for multiple times, and then washed with 0.3M sodium hydroxide solution for multiple times to obtain 70g of wet lithium extraction resin, and the resin moisture content was 34wt.%, which was recorded as lithium extraction resin 7.

[0102] Example 8

[0103] Using chloromethylated styrene-divinylbenzene copolymer intermediate as polymer skeleton to graft 2,4-dihydroxy-5-nitro-benzophenone: 20g of dried spherical chloromethylated styrene-divinylbenzene copolymer intermediate (<100 mesh, divinylbenzene content of 0.5%, chlorine content of 20wt%) was added to a 250mL spherical reaction bottle, 120mL of N,N-dimethylformamide (DMF) was added, and the mixture was stirred at room temperature for 2 hours, and then 60mmol of 2,4-dihydroxy-5-nitro-benzophenone, 70mmol of potassium carbonate, and 0.5g of potassium iodide were added, and the mixture was heated to 90°C and stirred for 16 hours. After the reaction was completed, the mixture was naturally cooled to room temperature, the DMF mother liquor was filtered out, and the resin balls were washed with 0.1M dilute sulfuric acid for multiple times, and then washed with 0.3M sodium hydroxide solution for multiple times to obtain 70g of wet lithium extraction resin, and the resin moisture content was 34wt.%, which was recorded as lithium extraction resin 8.

[0104] Example 9

[0105] Hydrophilic modification of lithium extraction resin 8: Take 30g of the washed and dried lithium extraction resin 8 and place it in a 250mL round-bottom flask, add 100mL of tetrahydrofuran to swell for 2 hours, then add 20mmol each of trimethylamine hydrochloride and solid sodium hydroxide, stir and react at room temperature for 10 hours, then filter out the reaction mother liquor, wash the resin with water several times, and obtain the hydrophilically modified lithium extraction resin 8, which is recorded as lithium extraction resin 8P1.

[0106] Example 10

[0107] Hydrophilic modification of lithium extraction resin 8: Take 30g of washed and dried lithium extraction resin 8 and place it in a 250mL round-bottom flask, add 100mL of tetrahydrofuran to swell for 2 hours, then add 20mmol of triethanolamine, stir and react at 50℃ for 10 hours, then filter out the reaction mother liquor, wash the resin with water several times, and obtain hydrophilically modified lithium extraction resin 8, which is recorded as lithium extraction resin 8P2.

[0108] Embodiment 11

[0109] Neutral synergistic chelating ligand modification of lithium extraction resin 8: 30g of washed and dried lithium extraction resin 8 was placed in a 250mL round-bottom flask, 100mL DMF was added to swell for 2 hours, and then (2-hydroxybenzyl) diphenylphosphine oxide 40mmol, potassium carbonate 50mmol, potassium iodide 0.5g were added, and the mixture was heated to 90°C and stirred for 16 hours. After the reaction was completed, the mixture was naturally cooled to room temperature, the DMF mother liquor was filtered out, and the resin balls were washed with 0.1M dilute sulfuric acid for multiple times, and then washed with 0.3M sodium hydroxide solution for multiple times to obtain 78g of wet lithium extraction resin, and the resin water content was 35wt.%, which was recorded as lithium extraction resin 8P3.

[0110] Example 12

[0111] Neutral synergistic chelating ligand modification of lithium extraction resin 8: 30g of washed and dried lithium extraction resin 8 was placed in a 250mL round-bottom flask, 100mL DMF was added to swell for 2 hours, and then 30mmol of hydroxybenzo-12-crown 4, 40mmol of potassium carbonate, and 0.5g of potassium iodide were added, and the mixture was heated to 90°C and stirred for 16 hours. After the reaction was completed, the mixture was naturally cooled to room temperature, the DMF mother liquor was filtered out, and the resin balls were washed with 0.1M dilute sulfuric acid for many times, and then washed with 0.3M sodium hydroxide solution for many times to obtain 59g of wet lithium extraction resin, and the resin water content was 33wt.%, which was recorded as lithium extraction resin 8P4.

[0112] Embodiment 13

[0113] Preparation of chloromethylated styrene-divinylbenzene copolymer sulfonated intermediate: 200g of dry spherical chloromethylated styrene-divinylbenzene copolymer intermediate (<30 mesh, divinylbenzene content of 0.5%, chlorine content of 20wt%) was added to a 1000mL spherical reaction bottle, 1000mL of ethylene dichloride was added, and the mixture was stirred and swollen at room temperature for 2 hours, then heated to 60°C, 50mL of 98wt% concentrated sulfuric acid was slowly added dropwise, and the reaction was stirred. After 2 hours, the resin turned brown, the reaction was stopped, the ethylene dichloride solvent was distilled off under reduced pressure at 60°C, the resin was washed with water several times until neutral, 30g of 30wt.% sodium hydroxide was added to transform the resin into a sodium type, and then dried at 70°C to obtain 280g of sulfonated intermediate.

[0114] Embodiment 14

[0115] Take 20g of the chloromethylated styrene-divinylbenzene copolymer sulfonated intermediate prepared in Example 13 in a 250mL spherical reaction bottle, add 120mL of N,N-dimethylformamide (DMF), stir and swell at room temperature for 2 hours, then add 90mmol of 2,4-dihydroxybenzophenone, 100mmol of potassium carbonate, and 0.5g of potassium iodide, and heat to 90°C for stirring and reaction for 16 hours. After the reaction is completed, cool naturally to room temperature, filter out the DMF mother liquor, wash the resin balls with 0.1M dilute sulfuric acid several times, and then wash the resin balls with 0.3M sodium hydroxide solution several times to obtain 62g of wet lithium extraction resin, and the resin water content is 33wt.%, recorded as lithium extraction resin 14.

[0116] Embodiment 15

[0117] Grafting 2,4-dihydroxybenzophenone with polyvinyl chloride as the polymer skeleton: 20g of polyvinyl chloride powder (<100 mesh, chlorine content 56-58wt%) was added to a 250mL spherical reaction bottle, and 120mL of N,N-dimethylformamide (DMF) was added. The mixture was stirred at room temperature for 2 hours to dissolve, and then 90mmol of 2,4-dihydroxybenzophenone, 100mmol of cesium carbonate, and 0.5g of potassium iodide were added. The mixture was heated to 90°C and stirred for 16 hours. After the reaction was completed, the mixture was cooled to room temperature naturally, 500mL of water was added, and the DMF+water mixture was filtered out. The resin powder was washed with 0.1M dilute sulfuric acid for many times, and then washed with 0.3M sodium hydroxide solution for many times to obtain 42g of wet lithium extraction resin powder, which was recorded as lithium extraction resin 15.

[0118] Example 16

[0119] 2,4-dihydroxybenzophenone was grafted onto poly 2,6-dimethyl-1,4-phenylene ether (PPO) as the polymer backbone: 20 g of poly 2,6-dimethyl-1,4-phenylene ether (PPO) powder was placed in a 250 mL spherical reaction bottle, 120 mL of dichloroethane was added, and the mixture was stirred at room temperature for 2 hours to dissolve. Then 90 mmol of N-bromosuccinimide (NBS) was added, and the mixture was heated to reflux for 8 hours. The dichloroethane solvent was then distilled off under reduced pressure to obtain bromomethylated PPO, which was then completely dissolved in 150 mL of N,N-dimethylformamide (DMF), 90 mmol of 2,4-dihydroxybenzophenone, 100 mmol of potassium carbonate, and 0.5 g of potassium iodide were added, and the mixture was heated to 90°C and stirred for 16 hours. After the reaction was completed, the mixture was naturally cooled to room temperature, 500 mL of water was added, the DMF+water mixture was filtered out, the resin powder was washed several times with 0.1 M dilute sulfuric acid, and then washed several times with 0.3 M sodium hydroxide solution to obtain 50 g of wet lithium extraction resin powder, which was recorded as lithium extraction resin 16.

[0120] Embodiment 17

[0121] Styrene-divinylbenzene-4-(4-vinylbenzyloxy)-2-hydroxybenzophenone suspension copolymerization: 1) Preparation of 4-(4-vinylbenzyloxy)-2-hydroxybenzophenone polymerization monomer: 90mmol of 2,4-dihydroxybenzophenone, 100mmol of potassium carbonate, and 0.5g of tetrabutylammonium bromide catalyst were added to 200mL of acetone solvent, heated to 70°C to dissolve for half an hour, and then 90mmol of 4-vinylbenzyl chloride was added dropwise. After the addition was completed, the reaction was carried out for 7 hours, and then 500mL of deionized water was added to precipitate a solid product, which was filtered, washed several times, and dried to obtain 30g of the product for standby use. 2) Take 100g of styrene, wash it with 10wt% sodium hydroxide aqueous solution several times to remove the inhibitor and set it aside; take 7g of divinylbenzene, wash it with 10wt% sodium hydroxide aqueous solution several times to remove the inhibitor and set it aside; mix 30g of 4-(4-vinylbenzyloxy)-2-hydroxybenzophenone with 100g of styrene and 7g of divinylbenzene after deblocking, add 2.5g of benzoyl peroxide, mix well and add dropwise to the suspension polymerization aqueous phase under strong stirring. The configuration process of the suspension polymerization aqueous phase is: add 400mL of deionized water, 100g of sodium chloride, and 5g of polyvinyl alcohol to a 1000mL round-bottom flask, stir the solution to a uniform solution, the reaction temperature is 80°C, and the polymerization time is 8 hours. After the reaction is completed, filter out the solution to obtain 120g of lithium extraction resin balls, which are recorded as lithium extraction resin 17.

[0122] Embodiment 18

[0123] Styrene-divinylbenzene-4-(4-vinylbenzyloxy)-2-hydroxybenzophenone-4-vinylbenzenesulfonic acid suspension copolymerization: 1) Preparation of 4-(4-vinylbenzyloxy)-2-hydroxybenzophenone polymerization monomer: 90mmol of 2,4-dihydroxybenzophenone, 100mmol of potassium carbonate, and 0.5g of tetrabutylammonium bromide catalyst were added to 200mL of acetone solvent, heated to 70°C to dissolve for half an hour, and then 90mmol of 4-vinylbenzyl chloride was added dropwise. After the addition was completed, the reaction was carried out for 7 hours, and then 500mL of deionized water was added to precipitate a solid product, which was filtered, washed several times, and dried to obtain 30g of the product for standby use. 2) Take 100g of styrene, wash it with 10wt% sodium hydroxide aqueous solution several times to remove the inhibitor and set it aside; take 7g of divinylbenzene, wash it with 10wt% sodium hydroxide aqueous solution several times to remove the inhibitor and set it aside; mix 30g of 4-(4-vinylbenzyloxy)-2-hydroxybenzophenone with 100g of styrene, 7g of divinylbenzene and 10g of 4-vinylbenzenesulfonic acid after deblocking, add 3.5g of benzoyl peroxide, mix well and add dropwise to the suspension polymerization aqueous phase under strong stirring. The configuration process of the suspension polymerization aqueous phase is: add 400mL of deionized water, 100g of sodium chloride, and 5g of polyvinyl alcohol to a 1000mL round-bottom flask, stir the solution to a uniform solution, the reaction temperature is 90°C, and the polymerization time is 6 hours. After the reaction is completed, filter out the solution to obtain 130g of lithium extraction resin balls, which are recorded as lithium extraction resin 18.

[0124] Embodiment 19

[0125] Styrene-divinylbenzene-4-(4-vinylbenzyloxy)-2-hydroxybenzophenone-triethyl(4-vinylbenzyl)ammonium chloride suspension copolymerization: 1) Preparation of 4-(4-vinylbenzyloxy)-2-hydroxybenzophenone polymerization monomer: 90mmol of 2,4-dihydroxybenzophenone, 100mmol of potassium carbonate, and 0.5g of tetrabutylammonium bromide catalyst were added to 200mL of acetone solvent, heated to 70°C to dissolve for half an hour, and then 90mmol of 4-vinylbenzyl chloride was added dropwise. After the addition was completed, the reaction was carried out for 7 hours, and then 500mL of deionized water was added to precipitate a solid product, which was filtered, washed several times, and dried to obtain 30g of the product for standby use. 2) Take 100g of styrene, wash it with 10wt% sodium hydroxide aqueous solution several times to remove the inhibitor and set it aside; take 7g of divinylbenzene, wash it with 10wt% sodium hydroxide aqueous solution several times to remove the inhibitor and set it aside; mix 30g of 4-(4-vinylbenzyloxy)-2-hydroxybenzophenone with 100g of styrene, 7g of divinylbenzene and 15g of triethyl (4-vinylbenzyl) ammonium chloride after blocking, add 3.5g of benzoyl peroxide, mix well and add dropwise to the suspension polymerization aqueous phase under strong stirring. The configuration process of the suspension polymerization aqueous phase is: add 400mL of deionized water, 100g of sodium chloride, and 5g of polyvinyl alcohol to a 1000mL round-bottom flask, stir the solution to a uniform solution, the reaction temperature is 90°C, and the polymerization time is 6 hours. After the reaction is completed, filter out the solution to obtain 137g of lithium extraction resin balls, which are recorded as lithium extraction resin 19.

[0126] Embodiment 20

[0127] The static lithium exchange performance test of the lithium-extracting resin prepared in Examples 1 to 19: 1) The experimental raw material brine is a 0.25 mol / L lithium hydroxide aqueous solution (lithium concentration is 1.73 g / L); 2) During the experiment, 5 g of wet resin was added with 20 mL of the experimental raw material brine, and oscillated at room temperature for 24 hours. The residual liquid was diluted and the lithium content was determined by ion chromatography (IC), and the exchange capacity was calculated. The results are listed in Table 1 below:

[0128] Table 1: Static lithium exchange performance of lithium-extraction resins prepared in Examples 1 to 19

[0129] Lithium Extraction Resin No. Equilibrium lithium concentration (g / L) Exchangeable lithium capacity (mg / g wet resin) 1 1.12 2.44 2 0.86 3.48 3 1.26 1.88 4 0.71 4.08 5 0.79 3.76 6 1.34 1.56 7 0.57 4.64 8 0.57 4.64 8P1 0.22 6.04 8P2 0.21 6.08 8P3 0.25 5.92 8P4 0.30 5.72 14 0.12 6.44 15 1.38 1.40 16 1.27 1.84 17 0.62 4.44 18 0.33 5.60 19 0.47 5.04

[0130] Embodiment 21

[0131] The static separation performance of lithium / sodium, lithium / potassium, lithium / rubidium and lithium / cesium of the lithium extraction resin prepared in Examples 1 to 19 was tested as follows: 1) The raw material brine was a mixed aqueous solution of lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide and cesium hydroxide (Li + =0.376g / L, Na + =0.498g / L, K +=0.442g / L, Rb + =0.741g / L, Cs + =1.477g / L, pH=13); 2) Experimental process: Take 5g of wet resin, add 20mL of experimental raw material brine, oscillate at room temperature for 24 hours, take the remaining liquid and dilute it, and use ion chromatography (IC) to determine the contents of lithium, sodium, potassium, rubidium and cesium, and calculate the separation factor α (A / B). The results are listed in Table 2 below.

[0132] Table 2: Static separation performance of lithium / sodium, lithium / potassium, lithium / rubidium and lithium / cesium of the lithium extraction resins prepared in Examples 1 to 19

[0133] Lithium Extraction Resin No. α(Li / Na) α(Li / K) α(Li / Rb) α(Li / Cs) 1 5.2 8.0 8.8 9.2 2 4.4 6.1 8.7 9.7 3 5.1 7.4 7.3 8.6 4 5.8 7.3 7.2 9.0 5 6.8 9.3 11.2 15 6 7.2 10.1 11.2 14.8 7 3.7 5.4 7.2 8.0 8 3.2 5.1 7.4 8.2 8P1 3.2 5.1 7.4 8.2 8P2 3.0 4.9 7.1 9.2 8P3 10.3 14.4 15.5 18.1 8P4 13.7 20.5 27.3 30.5 14 2.7 4.5 6.1 6.2 15 5.7 8.9 8.3 10.4 16 5.1 8.0 9.2 9.3 17 8.7 10.2 15.5 19.7 18 3.2 4.9 7.2 9.1 19 3.5 5.6 6.3 8.8

[0134] Embodiment 22

[0135] Dynamic lithium extraction performance test of lithium extraction resin 8P3 prepared in Example 11 (low sodium / lithium, potassium / lithium, rubidium / lithium and cesium / lithium ratio brine):

[0136] 1) The raw material brine is a mixed aqueous solution of lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide and cesium hydroxide (Li + =0.376g / L, Na + =0.498g / L, K + =0.442g / L, Rb + =0.741g / L, Cs + =1.477g / L, pH=13); 2) Experimental process: 60g of wet resin was loaded into a In an ion exchange column with a length of 50 cm, the experimental raw material brine was passed through the resin column at a flow rate of 1 to 1.5 mL / min, the effluent was collected in sections, and the composition of the effluent was detected by ion chromatography (IC). The resin column was then washed with water, and then lithium was eluted with 0.1 mol / L hydrochloric acid. The resulting operating curve is shown in the figure below: Figure 1 As shown, the system separation factors are α(Li / Na)=62.89, α(Li / K)=69.91, α(Li / Rb)=66.59, and α(Li / Cs)=42.18.

[0137] Embodiment 23

[0138] Dynamic lithium extraction performance test of lithium extraction resin 8P3 prepared in Example 11 (high sodium / lithium, potassium / lithium, rubidium / lithium and cesium / lithium ratio brine):

[0139] 1) The raw material brine is a real brine containing lithium, sodium, potassium, rubidium and cesium chloride (Li + =0.202g / L, Na + =90.350g / L, K +=77.858g / L, Rb + =2.947g / L, Cs + =2.196 g / L, OH - The concentration is 0.2 mol / L); 2) Experimental process: The resin column in Example 22 is used again, and the experimental raw material brine is passed through the resin column at a flow rate of 1-1.5 mL / min. The effluent is collected in sections, and the composition of the effluent is detected by ion chromatography (IC). The resin column is then washed with water, and then lithium is eluted with 0.1 mol / L hydrochloric acid. The obtained operation curve is as follows Figure 2 As shown, the system separation factors are α(Li / Na)=733.08, α(Li / K)=1281.99, α(Li / Rb)>10000, and α(Li / Cs)>10000.

[0140] Example 24. Cyclic performance of lithium extraction resin

[0141] Take 5g of lithium-extracting resin 1, add 20mL of 0.25mol / L lithium hydroxide aqueous solution (lithium concentration determined by ion chromatography is 1.73g / L), shake and react for 24 hours, measure the lithium ion concentration in the residual solution, and calculate the amount of lithium exchanged into the resin. Lithium exchange capacity = (Li 原始 -Li 余液 )g / L×20mL / 5g. After that, the remaining liquid was separated and 20mL of 0.2mol / L hydrochloric acid solution was added to elute lithium and regenerate the resin. After 24 hours of oscillation reaction, the eluate was separated and washed with secondary water until neutral, and used for the next lithium exchange capacity determination. The above experimental process was repeated 10 times, and the lithium exchange capacity obtained each time was as follows Figure 3 .

[0142] Example 25. Infrared spectrum of lithium extraction resin

[0143] The infrared spectra of lithium extraction resins 1 and 3 are shown in Figure 4 As shown in Figure 2, both lithium-extracting resins are grafted products of chloromethylated styrene-divinylbenzene spherical copolymers. After grafting, the infrared vibration of the C-Cl of the chloromethyl group (ν = 670 cm -1 ) characteristics disappeared, and the characteristic infrared absorption of ether bond and ketone group appeared (ν=3020~3050cm -1 ; ν=1680~1700cm -1 )

[0144] Example 26. Comparison of micrographs of the backbone resin before grafting and the lithium-extracting resin after grafting

[0145] Figure 5 This is a micrograph of the styrene-divinylbenzene copolymer skeleton resin sphere before grafting. Figure 6This is a micrograph of lithium-extracting resin spheres grafted with styrene-divinylbenzene copolymer backbone. Figure 5 and Figure 6 It can be seen that after grafting, the resin balls become larger and the color turns yellow.

[0146] Example 27. Determination of exchange capacity (for characterizing grafting effect)

[0147] Take 5g of lithium-extracting resin balls that have been washed and dried with filter paper, add 20mL of 0.25mol / L lithium hydroxide aqueous solution (lithium concentration is 1.73g / L), shake at room temperature for 24 hours, take the remaining solution and dilute it, and use ion chromatography (IC) to determine the lithium content, so as to calculate the exchange capacity of the resin: lithium exchange capacity = (Li 原始 -Li 余液 )g / L×20mL / 5g. Furthermore, the resin beads loaded with lithium were separated and washed with water twice, and then titrated with 0.2mol / L hydrochloric acid (methyl orange as an indicator) to determine the acid consumption of the resin beads loaded with lithium, thereby calculating the exchange capacity during elution: lithium exchange capacity = hydrochloric acid titration L×0.2mol / L×6.94 / 5g.

[0148] The above description is merely an exemplary embodiment of the present invention and is not intended to limit the protection scope of the present invention. The protection scope of the present invention is determined by the appended claims.

Claims

1. A lithium ion selective resin comprising at least one 2-hydroxybenzophenone (or aldehyde) functional group having a structure of formula (I), wherein: R1 is hydrogen, optionally substituted C1-C4 alkyl or optionally substituted benzene, wherein the substitution is carried out by a group selected from the group consisting of C1-C4 alkyl, C1-C4 alkoxy, halogen and phenyl; R2, R3, R4 and R5 are each independently hydrogen, halogen, nitro, benzyloxy, C 1-4 Alkyl, C 1-4 Alkoxy or linking group, provided that at least one of R2, R3, R4 and R5 is a linking group, which connects the structure of formula (I) to the polymer backbone via a covalent bond.

2. The lithium ion selective resin of claim 1, wherein R1 in the structure of formula (I) is hydrogen, methyl or phenyl.

3. The lithium ion selective resin according to claim 1 or 2, wherein one of R2 to R5 in the structure of formula (I) is a linking group, and the others are all H.

4. The lithium ion selective resin according to claim 1 or 2, wherein one of R2 to R5 is a nitro group.

5. The lithium ion selective resin of claim 4, wherein except for the nitro group and the linking group, the rest of R2 to R5 are H.

6. The lithium ion selective resin according to any one of claims 1 to 5, wherein The connecting groups in R2 to R5 connected to the polymer backbone are ether bonds, so that the molecular structure containing formula (I) is grafted onto the polymer backbone.

7. The lithium ion selective resin of claim 6, which has a structure of one of formulas (II) to (V) 8. The lithium ion selective resin of claim 7, wherein the R1 group is hydrogen, methyl or benzene, and R2 to R4 are all H.

9. The lithium ion selective resin of claim 7, wherein the R1 group is hydrogen, methyl or benzene; one of R2 to R4 is a nitro group, and the others are all H.

10. The lithium ion selective resin according to any one of claims 1 to 9, wherein the polymer backbone is a polymer capable of being halomethylated or halogenated.

11. The lithium ion selective resin of claim 10, wherein the polymer backbone is styrene-divinylbenzene copolymer, polyvinyl chloride, polyphenylene ether, polyetheretherketone, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, ethylene-propylene rubber-styrene-acrylonitrile copolymer, acrylonitrile-butyl acrylate-styrene copolymer, acrylonitrile-vinyl chloride-styrene copolymer, methyl (meth)acrylate-butadiene-styrene copolymer, or styrene-butylene copolymer.

12. The lithium ion selective resin according to any one of claims 1 to 11, wherein the crosslinking degree of the polymer backbone is 0 to 7 wt.%.

13. The lithium ion selective resin according to any one of claims 1 to 12, wherein the polymer skeleton has a gel structure or a macroporous structure.

14. The lithium ion selective resin of claim 13, wherein the polymer skeleton is spherical.

15. The lithium ion selective resin according to claim 14, wherein the sphere diameter of the polymer skeleton is 0.1 to 1.5 mm.

16. The lithium ion selective resin of any one of claims 1 to 15, wherein the 2-hydroxybenzophenone (or aldehyde) type functional group having the structure of formula (I) is derived from a lithium chelating functional monomer selected from the group consisting of 2,4-dihydroxybenzaldehyde, 2,4-dihydroxyacetophenone, 2,4-dihydroxypropiophenone, 2,4-dihydroxybutyrophenone, 2,4-dihydroxybenzophenone, 2,6-dihydroxybenzaldehyde, 2,6-dihydroxyacetophenone, 2,6-dihydroxypropiophenone, 2,6-dihydroxybutyrophenone, 2,6-dihydroxybenzophenone, 2,4-dihydroxy-5-nitro-benzaldehyde, 2,4-dihydroxy-5-nitro-acetophenone, 2,4-dihydroxy-5-nitro-propiophenone, 2,4-dihydroxy-5-nitro-benzophenone, 2,4-dihydroxy-5-nitro-benzophenone, 2,4-dihydroxy-2-nitro-benzophenone, 2,4-dihydroxy-3-nitro-benzophenone, 2,4-dihydroxy-4-nitro-benzophenone, 2,4-dihydroxy-5-nitro-benzophenone, 2,4-dihydroxy-6-nitro-benzophenone, 2,4-dihydroxy-7-nitro-benzophenone, 2,4-dihydroxy-8-nitro-benzophenone, 2,4-dihydroxy-9-nitro-benzophenone, 2,4-dihydroxy-10-nitro-benzophenone, 2,4-dihydroxy-11-nitro-benzophenone, 2,4-dihydroxy-12-nitro-benzophenone, 2,4-dihydroxy-13-nitro-benzophenone, 2,4-dihydroxy-14-nitro-benzophenone, 2,4-dihydroxy-15-nitro-benzophenone Hydroxy-3-nitro-benzaldehyde, 2,4-dihydroxy-3-nitro-acetophenone, 2,4-dihydroxy-3-nitro-propiophenone, 2,4-dihydroxy-3-nitro-butyrophenone, 2,4-dihydroxy-3-nitro-benzophenone, 2,6-dihydroxy-3-nitro-benzaldehyde, 2,6-dihydroxy-3-nitro-acetophenone, 2,6-dihydroxy-3-nitro-propiophenone, 2,6-dihydroxy-3-nitro-propiophenone Hydroxy-3-nitro-butyrophenone, 2,6-dihydroxy-3-nitro-benzophenone, 2,6-dihydroxy-5-nitro-benzaldehyde, 2,6-dihydroxy-5-nitro-acetophenone, 2,6-dihydroxy-5-nitro-propiophenone, 2,6-dihydroxy-5-nitro-butyrophenone, 2,6-dihydroxy-5-nitro-benzophenone, a mixture of one or more thereof, or halogenated derivatives of these substances.

17. The lithium ion selective resin according to claim 16, wherein The grafting amount of the lithium chelating functional monomer is 0.01-5 mmol / g resin.

18. The lithium ion selective resin according to any one of claims 1 to 17, further comprising a modification group for improving hydrophilicity.

19. The lithium ion selective resin of claim 18, wherein the modifying group for improving hydrophilicity comprises: One or more of sulfonic acid group, carboxylic acid group, phosphoric acid group, phenolic hydroxyl group, alcoholic hydroxyl group, iminodiacetic acid group, primary amine group, secondary amine group and quaternary ammonium group.

20. The lithium ion selective resin of claim 19, wherein the hydrophilicity-improving modifying group is derived from benzenesulfonic acid, benzoic acid, benzyl alcohol, acrylic acid, aminophosphoric acid, iminodiacetic acid, phenol, allyl alcohol, trimethylamine quaternary ammonium salt, triethylamine quaternary ammonium salt, triethanolamine quaternary ammonium salt, or triisopropanolamine quaternary ammonium salt.

21. The lithium ion selective resin according to any one of claims 18 to 20, wherein the grafting amount of the hydrophilicity-improving modifying group is 0 to 3 mmol / g of resin.

22. The lithium ion selective resin according to any one of claims 1 to 21, wherein The lithium ion selective resin further contains a cation exchange group or an anion exchange group.

23. The lithium ion selective resin of any one of claims 1 to 22, further comprising a covalently bonded neutral chelating functional group.

24. The lithium ion selective resin of claim 23, wherein the neutral chelating functional group is a ketone, an ester, a phosphine oxide or a crown ether.

25. The lithium ion selective resin of claim 24, wherein the neutral chelating functional group is derived from ethyl benzoate, (2-hydroxybenzyl)diphenylphosphine oxide, (2,5-dihydroxyphenyl)diphenylphosphine oxide, benzo-12-crown-4 or / and dibenzo-14-crown-4.

26. The lithium ion selective resin according to any one of claims 23 to 25, wherein the amount of the neutral chelating functional group grafted is 0 to 3 mmol / g of resin.

27. The lithium ion selective resin according to any one of claims 1 to 26, wherein the lithium saturation exchange capacity of the lithium ion selective resin is 0.05 to 1 mmol / g resin.

28. A method for extracting lithium, comprising: The lithium ion selective resin according to any one of claims 1 to 27 is contacted with a lithium-containing solution, and then the lithium ion selective resin is separated.

29. The method of claim 28, further comprising: A step of regenerating the lithium ion selective resin after contacting the resin with the lithium containing solution.

30. A method for preparing a lithium ion selective resin by grafting reaction, comprising: With halogenated polymer matrix and lithium chelating functional monomer as raw materials, the lithium chelating functional monomer is connected to the polymer matrix in the form of covalent bonds through etherification grafting reaction, thereby forming lithium ion selective resin balls or particles.

31. The method of claim 30, wherein the ether-forming grafting reaction is: using at least one of acetone, acetonitrile, tetrahydrofuran, N,N-dimethylformamide, and N,N-dimethylacetamide as a solvent, using at least one of lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, and cesium carbonate as a base, the molar ratio of the lithium chelating functional monomer to the halogen in the polymer matrix is ​​0.2 to 1.2, the molar ratio of the base to the lithium chelating functional monomer is 0.2 to 1.2, the amount of the solvent is 2 to 20 times the mass of the polymer matrix, the grafting reaction temperature is 40 to 120°C, and the reaction time is 2 to 72 hours.

32. The method of claim 30 or 31, wherein the polymer matrix is ​​a spherical chloromethylated styrene-divinylbenzene copolymer.

33. The method of claim 32, wherein the spherical chloromethylated styrene-divinylbenzene copolymer further contains a sulfonic acid group, a phosphonic acid group, or a carboxylic acid group.

34. The method of claim 32 or 33, wherein the spherical chloromethylated styrene-divinylbenzene copolymer has a chlorine content of 5 to 30 wt%.

35. The method of any one of claims 32 to 34, wherein the spherical chloromethylated styrene-divinylbenzene copolymer has a crosslinking degree of 0 to 5%.

36. The method of any one of claims 32-35, wherein The spherical chloromethylated styrene-divinylbenzene copolymer is prepared by chloromethylation reaction of white styrene-divinylbenzene copolymer spheres.

37. The method of any one of claims 30-36, wherein Tetrabutylammonium chloride, tetrabutylammonium bromide or tetrabutylammonium iodide is added as a phase transfer catalyst in the ether-forming grafting reaction.

38. The method of any one of claims 30-37, wherein Potassium iodide is added as a catalyst in the ether-forming grafting reaction.

39. A method for preparing a lithium ion selective resin by copolymerization, comprising: The lithium ion selective resin spheres or particles are prepared by copolymerizing a lithium chelating functional monomer bonded with 4-vinylbenzyl ether with 4-vinylstyrene and optionally divinylbenzene.

40. The method of claim 39, wherein the lithium ion selective resin beads or particles are prepared by suspension polymerization.

41. The method of claim 40, wherein the suspension polymerization method comprises mixing a lithium chelating functional monomer bonded to 4-vinylbenzyl ether with liquid styrene, optional divinylbenzene and an initiator, then dropping the mixture into an aqueous solution containing salt and a reinforcing dispersing aid under heating conditions, and reacting under strong stirring to obtain lithium ion selective resin beads or particles.

42. The method of any one of claims 39 to 41, wherein the molar ratio of styrene to the lithium chelating functional monomer bonded to 4-vinylbenzyl ether is 0.2 to 3.

43. The method of claim 42, wherein divinylbenzene is 0 to 7% by weight of the total weight of the lithium chelating functional monomers bonded to styrene and 4-vinylbenzyl ether.

44. The method of claim 41, wherein the salt used is sodium chloride.

45. The method of claim 41, wherein the strengthening dispersing aid used is polyvinyl alcohol.

46. ​​The method of any one of claims 39-45, further comprising copolymerizing 4-vinylbenzenesulfonic acid (sodium), (4-vinylbenzyl)trimethylammonium chloride or a lithium chelating functional monomer bonded to 4-vinylbenzyl alcohol and 4-vinylbenzyl ether, styrene and divinylbenzene.

47. The method of claim 46, wherein the amount of 4-vinylbenzenesulfonic acid (sodium), (4-vinylbenzyl)trimethylammonium chloride or 4-vinylbenzyl alcohol added is 0 to 3 mmol / g of resin.

Images