CN117839650A - Lithium ion sieve adsorbent, preparation method and application thereof - Google Patents

Abstract

The invention belongs to the technical field of lithium extraction in salt lakes, and particularly relates to a lithium ion sieve adsorbent, a preparation method and application thereof. The polyion liquid with phosphate groups is formed on the manganese ion sieve material, can be used as an adhesive, can play a role in extracting lithium, avoids the problem of reduced lithium extraction performance caused by the fact that the adhesive covers the adsorption active sites of the ion sieve, and can improve the adsorption capacity of lithium while reducing the dissolution loss rate of manganese.

Description

Lithium ion sieve adsorbent, preparation method and application thereof

Technical Field

The invention belongs to the technical field of lithium extraction in salt lakes, and particularly relates to a lithium ion sieve adsorbent, a preparation method and application thereof.

Background

Along with the rapid development of electronic products and new energy automobiles, the demand of lithium resources is increased year by year, but the supply of lithium resources is limited, and the contradiction between the supply and the demand of lithium resources promotes the efficient development and extraction of the lithium resources to become a research hot spot. Currently, lithium resources in salt lake brine are richer than ore lithium resources, and the defects of high energy consumption and high pollution commonly exist in the process of extracting lithium from the ore, so that the process of extracting lithium from the salt lake brine gradually becomes a main way for obtaining the lithium resources. At present, the development and utilization of salt lake brine lithium resources mainly use methods such as ion exchange and adsorption, extraction, nanofiltration, selective electrodialysis, electrochemistry and the like. The adsorbent method is a lithium extraction method which can realize selective adsorption of lithium ions by using the adsorbent, and can be desorbed through acid washing after the adsorption of lithium ions, so that the lithium ions are separated from other ions, and the method has the advantages of easy regeneration, simple operation, high recovery rate and the like, and is one of the very promising lithium extraction methods.

The lithium extraction adsorbent of the salt lake mainly comprises an aluminum adsorbent, a manganese adsorbent, a titanium adsorbent and the like. The manganese ion sieves prepared at present are all in powder form, have insufficient permeability and poor fluidity, and generally have the problems of high dissolution loss rate, low lithium recovery rate and reduced adsorption amount in the elution process. At present, the ion sieve shape is improved by mainly adopting a granulating method, a film-forming method, a foaming method, a nanofiber film method, a membrane electrode method, a magnetizing method and other forming modes. Among them, granulation is the most commonly used method of forming an ion sieve. Granulation is usually carried out by directly mixing and shaping a precursor with a binder, or cross-linking the precursor in a polymer solution to obtain a granular ion sieve adsorbent. However, the adsorption amount of the granulated adsorbent applied to the actual salt lake brine is reduced because the adsorption sites of the adsorbent are blocked by the binder or the polymer, so that the active sites for adsorbing lithium are reduced.

Therefore, there is a need to improve the preparation process of the manganese-series lithium ion sieve adsorbent so as to improve the stability of the ion sieve adsorbent and improve the adsorption capacity of lithium while reducing the dissolution loss rate of manganese.

In view of this, the present invention has been made.

Disclosure of Invention

The invention aims to provide a lithium ion sieve adsorbent, a preparation method and application thereof, and aims to reduce the dissolution loss rate of manganese and improve the adsorption capacity of lithium.

In order to achieve the above object of the present invention, the following technical solutions may be adopted:

in a first aspect, the present invention provides a solution comprising a lithium ion sieve adsorbent comprising a manganese-based ion sieve material having a polyionic liquid bound thereto;

wherein the anions in the polyionic liquid carry p=o groups.

In some embodiments of the invention, the lithium ion sieve adsorbent is polymerized from a vinyl modified adsorbent and an ionic liquid monomer; wherein the ionic liquid monomer contains a phosphate group and a vinyl group; the vinyl modified adsorbent comprises a manganese ion sieve material, and a silane coupling agent containing vinyl is combined on the manganese ion sieve material;

preferably, the ionic liquid monomer is selected from at least one of dibutyl 1-vinyl-3-ethylimidazole phosphate and diethyl 1-vinyl-3-ethylimidazole phosphate;

preferably, the manganese-based ion sieve material is selected from MnO ₂ ·0.5H ₂ O、λ-MnO ₂ And MnO ₂ ·0.3H ₂ At least one of O;

preferably, in the lithium ion sieve adsorbent, the mass ratio of the phosphoric acid groups is 15% -35%;

preferably, the silane coupling agent is selected from at least one of vinyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloylpropyl trimethoxysilane, vinyltriacetoxy silane, vinyltriisopropenyloxy silane, methylvinyldimethoxy silane, methylvinyldiethoxy silane, methacryloyloxy trimethoxysilane, methacryloyloxy triethoxysilane, and tetramethyl divinyl disiloxane.

In a second aspect, the present invention also provides a method for preparing a lithium ion sieve adsorbent, comprising: mixing and reacting the vinyl modified adsorbent with an ionic liquid monomer containing a phosphate group and vinyl to polymerize the ionic liquid monomer;

wherein the vinyl modified adsorbent comprises a manganese ion sieve material, and a silane coupling agent containing vinyl is combined on the manganese ion sieve material.

In some embodiments of the invention, there is provided: modifying the manganese ion sieve material by using a silane coupling agent containing vinyl to obtain a vinyl modified adsorbent, and mixing the vinyl modified adsorbent with an ionic liquid monomer for reaction;

preferably, the vinyl-modified adsorbent is prepared by the steps of: mixing manganese ion sieve material, silane coupling agent and solvent, and reacting for 12-24 hours at 40-85 ℃; more preferably, the silane coupling agent and the solvent are mixed to obtain a silane coupling agent solution, and the manganese ion sieve material and the silane coupling agent solution are mixed, wherein the concentration of the silane coupling agent solution is 0.5-10wt%;

preferably, the mass ratio of the manganese ion sieve material to the silane coupling agent is 1: (0.4-0.8); more preferably, the manganese-based ion sieve material has a particle size of 800 mesh to 1000 mesh;

preferably, the solvent is a mixed solvent formed by an organic solvent and water, and the mass fraction of the water in the mixed solvent is 5% -15%; more preferably, the organic solvent is selected from at least one of methanol, ethanol, isopropanol, dimethyl sulfoxide and N-methyl pyrrolidone;

preferably, after the reaction of the manganese ion sieve material and the silane coupling agent is completed, solid-liquid separation is carried out to obtain a solid material, and the solid material is washed and dried to obtain the vinyl modified adsorbent.

In some embodiments of the present invention, the vinyl modified adsorbent, solvent, ionic liquid monomer, crosslinking agent, initiator are mixed and polymerized at 65-75 ℃ for 6-24 hours;

preferably, the mass ratio of the vinyl modified adsorbent to the ionic liquid monomer is (5-15): 1, a step of;

preferably, the cross-linking agent is selected from at least one of ethylene glycol dimethacrylate and divinylbenzene; the mass ratio of the cross-linking agent to the ionic liquid monomer is (10-15): 100;

preferably, the initiator is selected from at least one of azobisisobutyronitrile and benzoyl peroxide; the mass ratio of the initiator to the ionic liquid monomer is (1.0-1.5): 100.

in some embodiments of the invention, the vinyl modified adsorbent and the solvent are mixed firstly, then the mixture is mixed with the ionic liquid monomer, the cross-linking agent and the initiator, inert gas is introduced for 30min-60min, and then the polymerization reaction is carried out under the airtight condition;

preferably, the solvent is selected from at least one of N, N-dimethylformamide and N-methylpyrrolidone; the dosage of the corresponding solvent of each gram of vinyl modified adsorbent is 1mL-3mL;

preferably, after the polymerization reaction is completed, solid-liquid separation is performed to obtain a solid material, and the solid material is washed and dried.

In some embodiments of the invention, the ionic liquid monomer is prepared by a process comprising: reacting a phosphoric acid-based organic compound with a vinyl compound;

wherein the phosphoric acid organic compound is at least one of tributyl phosphate and triethyl phosphate;

the vinyl compound is at least one selected from 1-vinylimidazole and 2-dimethylaminoethyl methacrylate;

preferably, the reaction temperature of the phosphoric acid organic compound and the vinyl compound is 120-160 ℃, and the reaction time is 10-20 h;

preferably, the molar ratio of the phosphoric acid organic compound to the vinyl compound is 1: (0.9-1.1);

preferably, after the reaction of the phosphoric acid-based organic compound with the vinyl compound is completed, extraction and washing are performed; wherein the extractant used in the extraction process is at least one selected from diethyl ether and ethyl acetate.

In a third aspect, the present invention further provides a lithium extraction method, where the lithium-containing brine is adsorbed by using the lithium ion sieve adsorbent in any of the above embodiments or the lithium ion sieve adsorbent prepared by the preparation method in any of the above embodiments.

In some embodiments of the invention, after adsorption is complete, the lithium ion sieve adsorbent is washed in an inorganic acid solution to obtain delithiated lithium ion sieve particles;

preferably, the concentration of the inorganic acid solution is 0.6mol/L to 1.1mol/L, and the mass ratio of the lithium ion sieve adsorbent to the inorganic acid solution is 1: (90-110).

In some embodiments of the invention, further comprising: mixing lithium ion sieve particles and phosphoric acid organic compounds, and reacting for 5-10 h at 120-160 ℃;

preferably, the phosphoric acid organic compound is at least one selected from tributyl phosphate and triethyl phosphate;

preferably, the mass ratio of the lithium ion removal sieve particles to the phosphoric acid organic compound is 1: (0.2-0.5);

preferably, after the reaction of the delithiated lithium ion sieve particles and the phosphoric acid organic compound is completed, the product is washed.

The polyion liquid with phosphate groups is formed on the manganese ion sieve material, and can be used as an adhesive, and can also be used as P=O-Li specific coordination bonds, coulomb force and Li in brine ⁺ The combination is carried out, thereby achieving the effect of extracting lithium, avoiding the problem of reduced performance of extracting lithium caused by the fact that the adhesive covers the adsorption active site of the ion sieve, and improving the adsorption capacity of lithium while reducing the dissolution loss rate of manganese.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a flow chart of the preparation of a lithium ion sieve adsorbent provided by the invention;

fig. 2 is a front-to-back infrared spectrogram of manganese ion sieve particles adsorbing lithium.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to examples, but it will be understood by those skilled in the art that the following examples are only for illustrating the present invention and should not be construed as limiting the scope of the present invention. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.

The endpoints of the ranges and any values disclosed in the present invention are not limited to the precise range or value, and the range or value should be understood to include values close to the range or value. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.

The embodiment of the invention provides a preparation method of a lithium ion sieve adsorbent, referring to fig. 1, comprising the following steps:

s1, providing ionic liquid monomer

The ionic liquid monomer contains a phosphate group and a vinyl group, the specific types are not limited, and the ionic liquid monomer containing the phosphate group and the vinyl group is suitable for the method provided by the invention.

In some embodiments of the present invention, the ionic liquid monomer is at least one selected from dibutyl 1-vinyl-3-ethylimidazole phosphate and diethyl 1-vinyl-3-ethylimidazole phosphate, and the ionic liquid monomer may be any one or more of the above, may be prepared by existing methods, or may be a commercially available material.

In some embodiments of the invention, the ionic liquid monomer is prepared by a process comprising: reacting a phosphoric acid-based organic compound with a vinyl compound; wherein, the phosphoric acid organic compound is at least one selected from tributyl phosphate and triethyl phosphate, and can be any one or more of the above; the vinyl compound is at least one selected from 1-vinylimidazole and 2-dimethylaminoethyl methacrylate, and can be any one or more of the above. Taking tributyl phosphate and 1-vinyl imidazole as examples, the 1-vinyl-3-ethyl imidazole dibutyl phosphate [ VEim ] [ DBP ] is obtained by reaction, and the synthesis reaction is as follows:

in some embodiments of the invention, the reaction temperature of the phosphoric acid organic compound and the vinyl compound is 120-160 ℃, the reaction time is 10-20 h, and the reaction is promoted to be fully carried out by regulating the reaction temperature and the reaction time, so that the utilization rate of raw materials is improved. Specifically, the reaction temperature may be 120 ℃, 130 ℃, 140 ℃, 150 ℃, 160 ℃, etc., and the reaction time may be 10 hours, 13 hours, 15 hours, 18 hours, 20 hours, etc.

Further, the molar ratio of the phosphoric acid organic compound to the vinyl compound is 1: (0.9-1.1), for example, 1:0.9, 1:1, 1:1.1, etc., preferably 1:1.

Further, after the reaction of the phosphoric acid organic compound with the vinyl compound is completed, extraction and washing are performed to remove unreacted phosphoric acid organic compound and vinyl compound. The extractant used in the extraction process is at least one selected from diethyl ether and ethyl acetate, and the extractant can be any one or more of the above.

S2, preparing vinyl modified adsorbent

And modifying the manganese ion sieve material by using a silane coupling agent containing vinyl to prepare the vinyl modified adsorbent.

In some embodiments of the invention, the vinyl-modified adsorbent is prepared by a process comprising: mixing manganese ion sieve material, silane coupling agent and solvent, and reacting at 40-85 deg.c for 12-24 hr. The reaction is fully carried out by regulating and controlling the reaction temperature and time. In the reaction process, the hydrolyzed product in the vinyl silane coupling agent has hydroxyl with stronger polarity, and can be subjected to condensation dehydration reaction with the hydroxyl on the surface of the manganese ion sieve material to form a covalent bond.

Specifically, the reaction temperature of the manganese ion sieve material and the silane coupling agent may be 40 ℃, 50 ℃, 60 ℃, 70 ℃, 80 ℃, 85 ℃ and the like, and the reaction time may be 12 hours, 15 hours, 18 hours, 20 hours, 24 hours and the like.

In some embodiments of the invention, the manganese-based ion sieve material is selected from MnO ₂ ·0.5H ₂ O、λ-MnO ₂ And MnO ₂ ·0.3H ₂ At least one of O can be any one or more of the above manganese ion sieve materials, and the above manganese ion sieve materials are all commercially available materials, such as MnO ₂ ·0.5H ₂ O is a manganese-based ion sieve product available from Wanlishi corporation.

Further, the particle size of the manganese ion sieve material is 800-1000 meshes, the manganese ion sieve material can be crushed before the reaction, and particularly, a high-speed crusher can be used for crushing, so that the particle size meets the requirement of 800-1000 meshes, the reaction is more fully carried out, and the influence of the overlarge particle size of the manganese ion sieve material on the introduction amount of vinyl is prevented. Specifically, the particle size of the manganese-based ion sieve material may be 800 mesh, 850 mesh, 900 mesh, 950 mesh, 1000 mesh, or the like.

In some embodiments of the present invention, the silane coupling agent is selected from at least one of vinyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloylpropyl trimethoxysilane, vinyltriacetoxy silane, vinyltriisopropenyloxy silane, methylvinyldimethoxy silane, methylvinyldiethoxy silane, methacryloyloxy trimethoxysilane, methacryloyloxy triethoxy silane, and tetramethyl divinyl disiloxane, and the silane coupling agent may be any one or more of the above materials, and the above materials are all commercially available materials, and can be used to modify manganese-based ion sieve materials, to prepare the vinyl modified adsorbent.

Further, the mass ratio of the manganese ion sieve material to the silane coupling agent is 1: (0.4-0.8), the introduced amount of the polyion liquid is controlled by regulating and controlling the mass ratio of the manganese ion sieve material to the silane coupling agent so as to regulate and control the introduced amount of vinyl, and the lithium adsorption capacity can be further improved in the range. Specifically, the mass ratio of the manganese ion sieve material to the silane coupling agent can be 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, and the like.

In the actual operation process, the silane coupling agent and the solvent can be mixed to obtain a silane coupling agent solution, then the manganese ion sieve material and the silane coupling agent solution are mixed, the concentration of the silane coupling agent solution is 0.5-10wt%, and the manganese ion sieve material and the silane coupling agent can fully react within the concentration range. Specifically, the concentration of the silane coupling agent solution may be 0.5wt%, 1.0wt%, 3.0wt%, 5.0wt%, 8.0wt%, 10.0wt%, or the like.

In some embodiments of the invention, the solvent is a mixed solvent formed by an organic solvent and water, the mass fraction of water in the mixed solvent is 5% -15%, and the organic solvent and water are adopted as the mixed solvent, so that the silane coupling agent can be better dissolved, and the reaction is promoted. Specifically, the mass fraction of water in the mixed solvent may be 5%, 8%, 10%, 12%, 15%, or the like.

Further, the organic solvent is at least one selected from methanol, ethanol, isopropanol, dimethyl sulfoxide and N-methyl pyrrolidone, and the organic solvent can be any one or more of the above.

In some embodiments of the invention, after the reaction of the manganese ion sieve material and the silane coupling agent is completed, solid-liquid separation is performed to obtain a solid material, and the solid material is washed and dried to obtain the vinyl modified adsorbent. The solid-liquid separation mode is not limited, and a conventional suction filtration mode can be adopted; the washing reagent used in the washing is not limited, and may be an organic alcohol such as ethanol; the temperature in the drying process is not limited, and the organic alcohol reagent on the surface can be sufficiently removed.

S3, polymerization

Mixing and reacting the vinyl modified adsorbent prepared in the step S2 with the ionic liquid monomer containing the phosphate group and the vinyl prepared in the step S1, and polymerizing the ionic liquid monomer.

In the actual operation process, mixing the vinyl modified adsorbent, the solvent, the ionic liquid monomer, the cross-linking agent and the initiator, and carrying out polymerization reaction for 6-24 h at 65-75 ℃, wherein the vinyl on the vinyl modified adsorbent and the vinyl in the ionic liquid monomer participate in the reaction in the polymerization process to form the polyionic liquid. Specifically, the polymerization reaction temperature may be 65 ℃, 70 ℃, 75 ℃, etc., and the polymerization reaction time may be 6 hours, 10 hours, 15 hours, 20 hours, 24 hours, etc.

In some embodiments of the present invention, the vinyl-modified adsorbent and the solvent may be mixed first, then with the ionic liquid monomer, the crosslinking agent and the initiator, and inert gas may be introduced for 30min to 60min to remove oxygen dissolved in the system, and then the polymerization reaction may be performed under closed conditions to prevent the interference reaction of oxygen. Specifically, the inert gas may be nitrogen, and the inert gas inlet time may be 30min, 40min, 50min, 60min, etc.

Further, the mass ratio of the vinyl modified adsorbent to the ionic liquid monomer is (5-15): and 1, controlling the mass ratio of the vinyl modified adsorbent to the ionic liquid monomer within the above range, so as to control the content of the polyionic liquid in the product within a better range and ensure the adsorption capacity of the adsorbent. Specifically, the mass ratio of the vinyl modified adsorbent to the ionic liquid monomer may be 5:1, 8:1, 10:1, 12:1, 15:1, etc.

In some embodiments of the present invention, the cross-linking agent is selected from at least one of ethylene glycol dimethacrylate and divinylbenzene, and the cross-linking agent may be any one or more of the above. The mass ratio of the cross-linking agent to the ionic liquid monomer is (10-15): the amount of the crosslinking agent is preferably within the above range, and the polymerization reaction can be promoted. Specifically, the mass ratio of the crosslinking agent to the ionic liquid monomer may be 10: 100. 11: 100. 12: 100. 13: 100. 14: 100. 15:100, etc.

In some embodiments of the invention, the initiator is selected from at least one of azobisisobutyronitrile and benzoyl peroxide. The initiator may be any one or more of the above. The mass ratio of the initiator to the ionic liquid monomer is (1.0-1.5): 100, the amount of the initiator used in the above range can promote the progress of the polymerization reaction. Specifically, the mass ratio of initiator to ionic liquid monomer may be 1.0:100, 1.1:100, 1.2:100, 1.3:100, 1.4:100, 1.5:100, etc.

In some embodiments of the present invention, the solvent is at least one selected from the group consisting of N, N-dimethylformamide and N-methylpyrrolidone, and the solvent may be any one or more of the above, and the vinyl-modified adsorbent may be well dispersed. The amount of the corresponding solvent per gram of the vinyl modified adsorbent is 1mL-3mL, and the solvent is preferably in the range, so that the concentration of the reaction raw materials is in a preferred range, and the reaction rate is improved. Specifically, the amount of the solvent to be used per gram of the vinyl-modified adsorbent may be 1mL, 2mL, 3mL, etc., and the amount of the solvent may be calculated based on the mass of the vinyl-modified adsorbent.

Further, after the polymerization reaction is completed, solid-liquid separation is carried out to obtain a solid material, and the solid material is washed and dried to obtain the lithium ion sieve adsorbent particles. The solid-liquid separation mode is not limited, and may be a general filtration mode; the washing reagent used in the washing is not limited, and can be organic alcohol such as methanol, and the washing reagent is preferably soaked and washed for a plurality of times by using the methanol; the drying temperature is not limited, and the organic alcohol may be removed.

The embodiment of the invention also provides a lithium ion sieve adsorbent, which comprises a manganese ion sieve material, wherein the manganese ion sieve material is combined with polyion liquid; wherein the polyionic liquid contains phosphate groups.

The ionic liquid [ VEIm ]][DBP]Through P=O-Li specific coordination bond and coulombic force and Li in brine ⁺ The combination is carried out, thereby achieving the effect of extracting lithium, and following reaction process is followed:

Li ⁺ +2[VEIm][DBP]+Cl ^- →LiCl·2[VEIm][DBP]；

the binder provided by the embodiment of the invention is polyion liquid based on [ VEim ] [ DBP ], and the polyion liquid is used as the binder and has the lithium extraction performance, so that the reduction of the lithium extraction performance caused by the binder covering the adsorption active site of the ion sieve is reduced.

In some embodiments of the invention, the lithium ion sieve adsorbent is polymerized from a vinyl modified adsorbent and an ionic liquid monomer; wherein the ionic liquid monomer contains a phosphate group and a vinyl group; the vinyl modified adsorbent comprises a manganese ion sieve material, and a silane coupling agent containing vinyl is combined on the manganese ion sieve material, and the specific preparation process can be referred to as the description above.

Further, in the lithium ion sieve adsorbent, the mass ratio of the phosphoric acid groups is 15% -35%, and the mass ratio of the phosphoric acid groups is preferably in the above range, so that the lithium extraction effect is further improved.

The embodiment of the invention also provides a lithium extraction method, the lithium ion sieve adsorbent provided by the embodiment of the invention is used for adsorbing lithium-containing brine, and compared with the common manganese ion sieve material, the lithium ion sieve adsorbent provided by the invention can further improve the adsorption capacity and reduce the dissolution loss rate of manganese in the adsorption regeneration process.

In some embodiments of the invention, after adsorption is complete, the lithium ion sieve adsorbent is washed in an inorganic acid solution to yield delithiated lithium ion sieve particles. In the pickling process, on the one hand, li ⁺ Removing from the manganese lithium ion sieve; li, on the other hand ⁺ From LiCl.2 [ VEIm ]][DBP]Middle prolapse, at the same time [ VEIm] ⁺ With Cl ^- Binding, [ DBP ]] ^- And H is ⁺ The dibutyl phosphate is formed by combination, and is adhered to the lithium ion sieve adsorbent particles due to the hydrophobicity, so that water pollution caused by entering into a water phase is avoided, and the dibutyl phosphate is also used as a raw material for regenerating the ionic liquid.

Further, when washing is performed in an inorganic acid solution, the concentration of the inorganic acid solution used is 0.6mol/L to 1.1mol/L, and the mass ratio of the lithium ion sieve adsorbent to the inorganic acid solution is 1: (90-110), the acid concentration is controlled to be 0.6mol/L-1.1mol/L in the acid washing process, the excessive acid concentration can damage the crystal structure of the manganese lithium ion sieve to increase the loss of manganese, and the insufficient acid concentration can lead to incomplete removal of lithium in the ionic liquid to reduce the adsorption capacity of lithium.

In some embodiments of the invention, further comprising: mixing the lithium ion removing sieve particles with phosphoric acid organic compounds, and reacting for 5-10 hours at 120-160 ℃ to regenerate the lithium ion removing sieve particles, thereby obtaining the poly-1-vinyl-3-ethylimidazole dibutyl phosphate [ VEIm ] [ DBP ]. The phosphoric acid organic compound used in this step is the same as the phosphoric acid organic compound used in step S2, and the phosphoric acid organic compound is at least one selected from tributyl phosphate and triethyl phosphate, and may be any one or more of the above.

Specifically, the reaction temperature of the lithium ion sieve particles and the phosphoric acid organic compound can be 120 ℃, 130 ℃, 140 ℃, 150 ℃, 160 ℃ and the like, and the reaction time can be 5 hours, 8 hours, 10 hours and the like.

Further, the mass ratio of the lithium ion removal sieve particles to the phosphoric acid organic compound is 1: (0.2-0.5), namely controlling the solid-liquid ratio to be 1: (0.2-0.5), such as may be 1:0.2, 1:0.3, 1:0.4, 1:0.5, etc.

Further, after the reaction of the lithium ion removing sieve particles and the phosphoric acid organic compound is completed, the product is washed to remove unreacted tributyl phosphate and regenerate to obtain 1-vinyl-3-ethylimidazole dibutyl phosphate [ VEim ] [ DBP ]. The washing agent used for washing is not limited and may be diethyl ether.

The features and capabilities of the present invention are described in further detail below in connection with the examples.

Example 1

The embodiment provides a preparation method of a lithium ion sieve adsorbent, which comprises the following specific steps:

(1) Tributyl phosphate and 1-vinyl imidazole in the molar ratio of 1:1 are placed in a flask, reflux condensation is carried out in an oil bath at the constant temperature of 140 ℃, magnetic stirring is carried out for 15h, the reaction product is removed from the flask, and unreacted tributyl phosphate and 1-vinyl imidazole are removed by extraction and washing with diethyl ether, thus obtaining 1-vinyl-3-ethylimidazole dibutyl phosphate [ VEim ] [ DBP ].

(2) Preparing a 3-methacryloyl propyl trimethoxy silane coupling agent solution with concentration of 5wt% by taking an aqueous solution containing 90wt% of methanol as a solvent, and adding MnO ₂ ·0.5H ₂ Pulverizing O material to 900 mesh by high speed pulverizer to obtain adsorbent powder, and mixing a certain amount of adsorbent powderAnd finally, uniformly dispersing the mixture in a silane coupling agent solution, reacting at 65 ℃ for 18 hours, filtering after the reaction is finished, washing the product with ethanol, and drying to obtain the vinyl modified adsorbent. Wherein, the mass ratio of the reactant raw material adsorbent powder to the silane coupling agent is controlled to be 1:0.6.

(3) And (3) the vinyl modified adsorbent obtained in the step (2) is prepared according to a solid-to-liquid ratio of 1g: dispersing 2mL of the mixture in an N, N-dimethylformamide solvent, adding the 1-butyl-3-methylimidazole dibutyl phosphate obtained in the step (1) as a polymerization monomer, ethylene glycol dimethacrylate as a crosslinking agent, azo-bis-isobutyronitrile as an initiator, introducing nitrogen for 40min, removing oxygen dissolved in the system, then reacting for 15h at 70 ℃ under a closed condition, filtering out reactants after the reaction, soaking and cleaning for 3 times by using methanol, and drying to obtain the lithium ion sieve adsorbent particles. The mass ratio of the vinyl modified adsorbent to the polymerized monomer is 10:1, the mass of the initiator is 1.2% of the mass of the polymerized monomer, and the mass of the crosslinking agent is 12% of the mass of the polymerized monomer.

The embodiment also provides a lithium extraction method, which comprises the following steps:

(1) Placing the lithium ion sieve adsorbent particles into lithium-containing brine for lithium adsorption, and placing the lithium ion sieve adsorbent particles into 0.8mol/L hydrochloric acid aqueous solution for washing after the adsorption is completed to obtain lithium ion sieve particles, wherein the solid-to-liquid ratio of the lithium ion sieve adsorbent particles to the hydrochloric acid solution is 1:100.

wherein, the composition of the lithium-containing brine is as follows: sodium ion (25.0 g/L), magnesium ion (32.4 g/L), lithium ion (0.6 g/L), chloride ion (311.3 g/L), and carbonate ion (15.5 g/L).

(2) Mixing lithium ion sieve particles with tributyl phosphate according to a solid-to-liquid ratio of 1:0.35, placing the mixture into a flask, refluxing and condensing the mixture in a constant-temperature oil bath at 140 ℃, magnetically stirring the mixture for reaction for 7 hours, removing the reacted product from the flask, washing the reaction product with diethyl ether to remove unreacted tributyl phosphate, and regenerating the reaction product to obtain 1-vinyl-3-ethylimidazole dibutyl phosphate [ VEim ] [ DBP ].

Example 2

The embodiment provides a preparation method of a lithium ion sieve adsorbent, which comprises the following specific steps:

(1) Tributyl phosphate and 1-vinyl imidazole in the molar ratio of 1:1 are placed in a flask, reflux condensation is carried out in an oil bath at the constant temperature of 120 ℃, magnetic stirring is carried out for 10 hours, the reaction product is removed from the flask, and unreacted tributyl phosphate and 1-vinyl imidazole are removed by extraction and washing with diethyl ether, thus obtaining 1-vinyl-3-ethylimidazole dibutyl phosphate [ VEim ] [ DBP ].

(2) Preparing 3-methacryloyl propyl trimethoxy silane coupling agent solution with concentration of 0.5wt% by taking aqueous solution containing 95wt% of methanol as solvent, and mixing MnO ₂ ·0.5H ₂ The O material is crushed to the particle size of 800 meshes by a high-speed crusher to obtain adsorbent powder, a certain amount of adsorbent powder is placed in a silane coupling agent solution to be uniformly dispersed, the mixture is reacted for 12 hours at the temperature of 85 ℃, and after the reaction is finished, the mixture is filtered by suction, and the product is washed by ethanol and dried to obtain the vinyl modified adsorbent. Wherein, the mass ratio of the reactant raw material adsorbent powder to the silane coupling agent is controlled to be 1:0.4.

(3) And (3) the vinyl modified adsorbent obtained in the step (2) is prepared according to a solid-to-liquid ratio of 1g: dispersing 1mL of the mixture in an N, N-dimethylformamide solvent, adding the dibutyl 1-butyl-3-methylimidazole phosphate obtained in the step (1) as a polymerization monomer, ethylene glycol dimethacrylate as a crosslinking agent, azodiisobutyronitrile as an initiator, introducing nitrogen for 30min, removing oxygen dissolved in the system, then reacting at 65 ℃ for 24h under a closed condition, filtering out reactants after the reaction, soaking and cleaning for 3 times by using methanol, and drying to obtain the lithium ion sieve adsorbent particles. The mass ratio of the vinyl modified adsorbent to the polymerized monomer is 5:1, the mass of the initiator is 1% of the mass of the polymerized monomer, and the mass of the crosslinking agent is 10% of the mass of the polymerized monomer.

The embodiment also provides a lithium extraction method, which comprises the following steps:

(1) Placing the lithium ion sieve adsorbent particles into lithium-containing brine (the composition is the same as that of example 1) for lithium adsorption, and placing the lithium ion sieve adsorbent particles into 0.6mol/L hydrochloric acid for washing after the adsorption is completed, wherein the solid-liquid ratio of the lithium ion sieve adsorbent particles to a hydrochloric acid solution is 1:100.

(2) Mixing lithium ion sieve particles with tributyl phosphate according to a solid-to-liquid ratio of 1:0.2, placing the mixture into a flask, refluxing and condensing the mixture in an oil bath with constant temperature of 120 ℃, magnetically stirring the mixture for reaction for 10 hours, removing the reacted product from the flask, washing the reaction product with diethyl ether to remove unreacted tributyl phosphate, and regenerating the reaction product to obtain 1-vinyl-3-ethylimidazole dibutyl phosphate [ VEim ] [ DBP ].

Example 3

The embodiment provides a preparation method of a lithium ion sieve adsorbent, which comprises the following specific steps:

(1) Tributyl phosphate and 1-vinyl imidazole in the molar ratio of 1:1 are placed in a flask, reflux condensation is carried out in an oil bath at the constant temperature of 160 ℃, magnetic stirring is carried out for 20 hours, the reaction product is removed from the flask, and unreacted tributyl phosphate and 1-vinyl imidazole are removed by extraction and washing with diethyl ether, so that 1-vinyl-3-ethylimidazole dibutyl phosphate [ VEim ] [ DBP ] is obtained.

(2) Preparing a 3-methacryloyl propyl trimethoxy silane coupling agent solution with the concentration of 10wt% by taking an aqueous solution containing 55wt% of methanol as a solvent, crushing MnO2.0.5H2O material to the particle size of 1000 meshes by a high-speed crusher to obtain adsorbent powder, uniformly dispersing a certain amount of adsorbent powder in the silane coupling agent solution, reacting at the temperature of 40 ℃ for 24 hours, filtering after the reaction is finished, washing the product by ethanol, and drying to obtain the vinyl modified adsorbent. The mass ratio of the adsorbent powder to the silane coupling agent is 1:0.8.

(3) And (3) the vinyl modified adsorbent obtained in the step (2) is prepared according to a solid-to-liquid ratio of 1g:3mL of the solution is dispersed in N, N-dimethylformamide, 1-butyl-3-methylimidazole dibutyl phosphate obtained in the step (1) is added as a polymerization monomer, ethylene glycol dimethacrylate is used as a cross-linking agent, azobisisobutyronitrile is used as an initiator, N-propanol is added as a pore-forming agent, nitrogen is introduced for 60min, oxygen dissolved in the system is removed, then the reaction is carried out for 6h at 75 ℃ under a closed condition, the reactant is filtered out after the reaction is finished, methanol is used for soaking and cleaning for 3 times, and the lithium ion sieve adsorbent particles are obtained after drying. The mass ratio of the vinyl modified adsorbent to the polymerized monomer is 15:1, the mass of the initiator is 1.5% of the mass of the polymerized monomer, and the mass of the crosslinking agent is 15% of the mass of the polymerized monomer.

The embodiment also provides a lithium extraction method, which comprises the following steps:

(1) Placing the lithium ion sieve adsorbent particles into lithium-containing brine for lithium adsorption, and placing the lithium ion sieve adsorbent particles into 1.1mol/L hydrochloric acid for washing after the adsorption is completed, wherein the solid-to-liquid ratio of the lithium ion sieve adsorbent particles to the hydrochloric acid solution is 1:100.

(2) Mixing lithium ion sieve particles and tributyl phosphate according to a solid-to-liquid ratio of 1:0.5, placing the mixture into a flask, refluxing and condensing the mixture in an oil bath with constant temperature of 160 ℃, magnetically stirring the mixture for reaction for 5 hours, removing the reacted product from the flask, washing the reaction product with diethyl ether to remove unreacted tributyl phosphate, and regenerating the reaction product to obtain 1-vinyl-3-ethylimidazole dibutyl phosphate [ VEim ] [ DBP ].

Example 4

Example 4 differs from example 1 only in that: when extracting lithium, the concentration of acid washing hydrochloric acid is 0.2mol/L.

Example 5

Example 5 differs from example 1 only in that: when extracting lithium, the concentration of acid washing hydrochloric acid is 1.5mol/L.

Example 6

Example 6 differs from example 1 only in that: the mass ratio of the vinyl modified adsorbent to the polymerized monomer in the step (3) is 2:1.

Example 7

Example 7 differs from example 1 only in that: the mass ratio of the vinyl modified adsorbent to the polymerized monomer in the step (3) is 20:1.

Example 8

Example 8 differs from example 1 only in that: the mass ratio of the adsorbent powder to the silane coupling agent in the step (2) is 1:0.1.

Example 9

Example 9 differs from example 1 only in that: the mass ratio of the adsorbent powder to the silane coupling agent in the step (2) is 1:1.3.

Example 10

Example 10 differs from example 1 only in that: the ionic liquid monomer prepared in the step (1) is 1-vinyl-3-butyl imidazole bromine salt [ VBIm ] Br ].

Example 11

Example 11 differs from example 1 only in that: the ionic liquid monomer prepared in the step (1) is diethyl 1-vinyl-3-ethylimidazole phosphate.

Comparative example 1

Comparative example 1 and example 1 differ only in that: comparative example 1 lithium extraction was performed directly using a manganese-based ion sieve material, without performing a granulation process.

Comparative example 2

Comparative example 2 differs from example 1 only in that: step (2) is omitted, and the silane coupling agent is not used for modifying the adsorbent.

Comparative example 3

The comparative example provides a preparation method of a lithium ion sieve adsorbent, which adopts a conventional method for preparation and comprises the following specific steps: the adsorbent powder consistent with example 1 is taken, and the adsorbent powder is mixed with polyvinylidene fluoride (PVDF) powder as a binder and N, N' -Dimethylacetamide (DMAC) as an organic solvent according to the mass ratio of 1:0.15: and 0.15, extruding and granulating by using a double-screw extruder, wherein the die head temperature of the extruder is 230 ℃, and granulating the extruded strips by using a granulator after extrusion to obtain porous granules.

The lithium extraction method provided in this comparative example is the same as in example 1.

Test example 1

The infrared spectrum test of the adsorbent particles prepared in example 1 before and after adsorbing lithium is shown in fig. 2.

As can be seen from FIG. 2, the infrared spectrum of the adsorbent is 600cm ^-1 The fundamental characteristic peak of Mn-O bond appears at 1243cm ^-1 The peak of the position is the stretching vibration peak of-P=O, when the infrared diagram of the adsorbent absorbs lithium, the stretching vibration peak of-P=O can be seen, and the stretching vibration peak is formed by 1243cm ^-1 Moving down to 1229cm-1, the wavenumber decreases due to the O atom in the-P=O bond and Li ⁺ After coordination, the bond energy of the P=O bond is weakened after the P=O-Li is formed, and the stretching vibration frequency is reduced. In addition, the peak intensity of the P=O bond is reduced after lithium adsorptionWeak, which may be related to a decrease in electron cloud density of O on-p=o, further illustrating Li ⁺ Electrons can be obtained from O of-p=o. Therefore, li is extracted in the lithium extraction process by using the adsorbent particles ⁺ Can be combined with a manganese ion sieve through ion exchange reaction and can be also selected from poly [ VEIm ]][DBP]Electrons are obtained on O of-P=O-Li in the ionic liquid, and based on the coordination bond of the electrons to the P=O-Li formed by action, the site for adsorbing lithium is increased after the granulation of the manganese-based lithium ion sieve, so that the capacity for adsorbing lithium after the formation of the manganese-based lithium ion sieve is improved.

Test example 2

The adsorbents prepared in examples and comparative examples were subjected to adsorption capacity test and manganese dissolution loss test, and the test results are shown in table 1.

The testing method comprises the following steps:

(1) Adsorption capacity test: the lithium ion sieve adsorbent particles were immersed in a lithium-containing solution (0.05 mol/L, S/l=1:1000) and shaken in a thermostatted shaking oven at 100rpm for 24h at 25 ℃ to ensure that the adsorption reached equilibrium. The Li+ content of the solution was determined using ICP-OES. The adsorption capacity Q (mg/g) is calculated as follows: q= (C ₀ -C _t ) V/m, wherein C ₀ (mg/L) is Li ⁺ Is a concentration of (1); ct (mg/L) is the concentration of lithium ions when the adsorption equilibrium is reached; v (L) is the volume of the solution; m (g) is the mass of the lithium ion sieve.

(2) Manganese dissolution loss test: the lithium ion sieve adsorbent particles were washed with HCl at a solid-to-liquid ratio of 1:100 at normal temperature for 24 hours, and then the supernatant was partially taken out with a pipette, and the concentration of metal cations in the solution was measured using ICP-OES, and then the dissolution loss rate of manganese (DE was calculated _Mn ) The calculation formula is as follows: DE (DE) _Mn ＝(C ₁ ×V ₁ ) In the formula (I), C ₁ (mg/L) is the detected concentration of manganese ions, V ₁ (L) is the solution volume, and m (g) is the mass of the adsorbent powder.

Table 1 adsorption capacity and manganese dissolution test results of adsorbents prepared in examples and comparative examples

It can be seen from table 1 that the manganese-based adsorbent prepared by the embodiment of the invention can obviously improve the adsorption capacity of lithium, reduce the dissolution loss rate of manganese and prolong the cycle service life of the adsorbent after being polymerized and granulated by using the ionic liquid.

As can be seen from examples 1, 4 and 5, too high an acid concentration during the acid leaching process may damage the crystal structure of the manganese-based ion sieve to increase the loss of manganese, and too low an acid concentration may cause incomplete removal of lithium from the ionic liquid to decrease the adsorption capacity of lithium.

Industrial applicability

The polyion liquid with phosphate groups is formed on the manganese ion sieve material, can be used as an adhesive, can also play a role in extracting lithium, is convenient to operate in a modification process, is mild and controllable in reaction condition, and has very good industrial practicability.

Claims (10)

1. A lithium ion sieve adsorbent, comprising a manganese ion sieve material, wherein a polyion liquid is combined on the manganese ion sieve material;

wherein the anions in the polyionic liquid carry a p=o group.

2. The lithium ion sieve adsorbent according to claim 1, wherein the lithium ion sieve adsorbent is obtained by polymerizing a vinyl-modified adsorbent and an ionic liquid monomer; wherein the ionic liquid monomer contains a phosphate group and a vinyl group; the vinyl modified adsorbent comprises a manganese ion sieve material, and a silane coupling agent containing vinyl is combined on the manganese ion sieve material;

preferably, the ionic liquid monomer is selected from at least one of dibutyl 1-vinyl-3-ethylimidazole phosphate and diethyl 1-vinyl-3-ethylimidazole phosphate;

preferably, the manganese-based ion sieve material is selected from MnO ₂ ·0.5H ₂ O、λ-MnO ₂ And MnO ₂ ·0.3H ₂ At least one of O;

preferably, in the lithium ion sieve adsorbent, the mass ratio of the phosphoric acid groups is 15% -35%;

preferably, the silane coupling agent is selected from at least one of vinyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloylpropyl trimethoxysilane, vinyltriacetoxy silane, vinyltriisopropenyloxy silane, methylvinyldimethoxy silane, methylvinyldiethoxy silane, methacryloyloxy trimethoxysilane, methacryloyloxy triethoxy silane, and tetramethyl divinyl disiloxane.

3. A method of preparing the lithium ion sieve adsorbent of any of claims 1-2, comprising: mixing and reacting a vinyl modified adsorbent and an ionic liquid monomer containing a phosphate group and vinyl, so that the ionic liquid monomer is polymerized;

wherein the vinyl modified adsorbent comprises a manganese ion sieve material, and a silane coupling agent containing vinyl is combined on the manganese ion sieve material.

4. A method of preparing as claimed in claim 3, comprising: modifying the manganese ion sieve material by using a silane coupling agent containing vinyl to obtain a vinyl modified adsorbent, and mixing the vinyl modified adsorbent with the ionic liquid monomer for reaction;

preferably, the preparation process of the vinyl modified adsorbent comprises the following steps: mixing the manganese ion sieve material, the silane coupling agent and the solvent, and reacting for 12-24 hours at the temperature of 40-85 ℃; more preferably, a silane coupling agent and a solvent are mixed to obtain a silane coupling agent solution, and the manganese ion sieve material and the silane coupling agent solution are mixed, wherein the concentration of the silane coupling agent solution is 0.5-10wt%;

preferably, the mass ratio of the manganese ion sieve material to the silane coupling agent is 1: (0.4-0.8); more preferably, the manganese-based ion sieve material has a particle size of 800 mesh to 1000 mesh;

preferably, the solvent is a mixed solvent formed by an organic solvent and water, and the mass fraction of the water in the mixed solvent is 5% -15%; more preferably, the organic solvent is selected from at least one of methanol, ethanol, isopropanol, dimethyl sulfoxide and N-methyl pyrrolidone;

preferably, after the reaction of the manganese ion sieve material and the silane coupling agent is completed, solid-liquid separation is carried out to obtain a solid material, and the solid material is washed and dried to obtain the vinyl modified adsorbent.

5. The preparation method according to claim 4, wherein the vinyl modified adsorbent, the solvent, the ionic liquid monomer, the crosslinking agent and the initiator are mixed and polymerized at 65-75 ℃ for 6-24 hours;

preferably, the mass ratio of the vinyl modified adsorbent to the ionic liquid monomer is (5-15): 1, a step of;

preferably, the crosslinking agent is selected from at least one of ethylene glycol dimethacrylate and divinylbenzene; the mass ratio of the cross-linking agent to the ionic liquid monomer is (10-15): 100;

preferably, the initiator is selected from at least one of azobisisobutyronitrile and benzoyl peroxide; the mass ratio of the initiator to the ionic liquid monomer is (1.0-1.5): 100.

6. the preparation method according to claim 5, wherein the vinyl-modified adsorbent and the solvent are mixed, then mixed with the ionic liquid monomer, the crosslinking agent and the initiator, and inert gas is introduced for 30min to 60min, and then polymerization is performed under closed conditions;

preferably, the solvent is selected from at least one of N, N-dimethylformamide and N-methylpyrrolidone; the dosage of the solvent corresponding to each gram of the vinyl modified adsorbent is 1mL-3mL;

preferably, after the polymerization reaction is completed, solid-liquid separation is performed to obtain a solid material, and the solid material is washed and dried.

7. A method of preparing according to claim 3, wherein the ionic liquid monomer is prepared by a process comprising: reacting a phosphoric acid-based organic compound with a vinyl compound;

wherein the phosphoric acid organic compound is at least one of tributyl phosphate and triethyl phosphate;

the vinyl compound is at least one selected from 1-vinylimidazole and 2-dimethylaminoethyl methacrylate;

preferably, the reaction temperature of the phosphoric acid organic compound and the vinyl compound is 120-160 ℃, and the reaction time is 10-20 h;

preferably, the molar ratio of the phosphoric acid-based organic compound to the vinyl compound is 1: (0.9-1.1);

preferably, after the reaction of the phosphoric acid-based organic compound with the vinyl compound is completed, extraction and washing are performed; wherein the extractant used in the extraction process is at least one selected from diethyl ether and ethyl acetate.

8. A lithium extraction method, characterized in that the lithium-containing brine is adsorbed by the lithium ion sieve adsorbent according to any one of claims 1-2 or the lithium ion sieve adsorbent prepared by the preparation method according to any one of claims 3-7.

9. The method according to claim 8, wherein after the adsorption is completed, the lithium ion sieve adsorbent is washed in an inorganic acid solution to obtain lithium ion sieve particles in a delithiated state;

preferably, the concentration of the inorganic acid solution is 0.6mol/L to 1.1mol/L, and the mass ratio of the lithium ion sieve adsorbent to the inorganic acid solution is 1: (90-110).

10. The lithium extraction method according to claim 9, further comprising: mixing the lithium ion sieve particles with phosphoric acid organic compounds, and reacting for 5-10 h at 120-160 ℃;

preferably, the phosphoric acid organic compound is at least one selected from tributyl phosphate and triethyl phosphate;

preferably, the mass ratio of the lithium ion removal sieve particles to the phosphoric acid organic compound is 1: (0.2-0.5);

preferably, after the reaction of the delithiated lithium ion sieve particles and the phosphoric acid based organic compound is completed, the product is washed.