High-capacity lithium adsorbent as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of materials, and relates to a high-capacity lithium adsorbent as well as a preparation method and application thereof. The method comprises the following steps: preparing an organic polymer spinning solution from an organic polymer framework material, a hydrophilic fragment material, a gradient pore forming agent and adsorbent active powder; performing wet spinning by using the organic polymer spinning solution to obtain a lithium adsorbent crude product; and performing post-treatment on the lithium adsorbent crude product to obtain a lithium adsorbent finished product. The lithium adsorbent disclosed by the invention can quickly adsorb lithium ions in a solution in a high-capacity manner in the presence of high-concentration impurity ions, and can solve the problems of low capacity and slow mass transfer rate of a granulation lithium adsorbent in the process of extracting lithium from a salt lake. The lithium adsorbent disclosed by the invention has excellent stability and durability, is low in operation cost and is suitable for an industrial-scale lithium extraction process.

Description

Technical Field

[0001] The present invention belongs to the technical field of materials, and relates to lithium ion adsorption materials, and in particular to a high-capacity lithium adsorbent, a preparation method thereof, and an application thereof. Background Art

[0002] Granulated lithium adsorbent is a material used to efficiently adsorb lithium ions, which plays an important role in the extraction and recovery of lithium resources. With the growing demand for lithium in electric vehicles and energy storage systems, the research and development of lithium adsorbents has become particularly important. Granulation technology can improve the mechanical strength and stability of the adsorbent, making it more suitable for industrial applications.

[0003] The research on granulated lithium adsorbents involves the synthesis and modification of various materials. The preparation of granular adsorbents can also optimize their porous structure and specific surface area by using different forming agents and granulation techniques, thereby improving the lithium adsorption capacity and mass transfer rate. The latest research and patents show that the development of granulated lithium adsorbents is moving towards improving lithium adsorption efficiency, cycle stability and industrial application potential.

[0004] The existing technology of lithium adsorbents has the following disadvantages: generally, adsorbent powder, polymer binder and solvent are blended and granulated, but in this process, a dense surface layer will be formed on the surface of the adsorbent, thereby affecting the mass transfer effect, and the effective loading amount of the adsorbent active powder is low, which limits its efficiency in industrial applications. The adsorbent particles granulated with certain polymer materials (such as polyvinyl chloride, polyvinylidene fluoride, etc.) have poor water permeability, which affects the efficiency of the adsorption process. The existing granulated lithium adsorbent has a large pore size, resulting in reduced adsorption efficiency and decreased strength. Some adsorbents have dissolution problems during use, which will reduce the service life of the adsorbent and the recovery rate of lithium. The hydraulic conductivity of the granulated adsorbent in the fixed bed is low, which affects the application of large-scale continuous industrial production. In the process of lithium extraction, traditional lithium adsorbents have limited adsorption capacity and low mass transfer rate, resulting in high industrial application costs, which greatly limits their application in large-scale lithium extraction processes. Summary of the invention

[0005] The main technical problem to be solved by the present invention is to provide a method for preparing lithium adsorbent materials for use in the fields of new energy, new materials, and especially in the process of lithium recovery. Different from the existing methods, the lithium adsorbent of the present invention can adsorb lithium ions in the solution with high capacity and quickly in the presence of high concentrations of impurity ions, aiming to solve the problem of low capacity and slow mass transfer rate of granulated lithium adsorbent in the process of lithium extraction from salt lakes.

[0006] In order to solve the above problems existing in the existing adsorbents, the purpose of the present invention is to provide a granular lithium adsorbent and a preparation method thereof. The obtained granular adsorbent has a large number of gradient pores, that is, the size of the pores in the microspheres is distributed in a radial gradient, and the microspheres present a structural hierarchy due to the different pore characteristics in different intervals, and the micropores between the layers can be gradually or step-like transition. In addition, the effective powder loading is high, which makes the adsorbent have a high adsorption capacity; at the same time, because the granular adsorbent has a large number of gradient pores and no dense surface layer, the mass transfer rate is faster, and the actual operation consumes less fresh water and lower energy consumption.

[0007] The preparation of the granulated lithium adsorbent of the present invention utilizes aluminum / titanium / manganese adsorbent active powder as a precursor. First, the adsorbent active powder is mixed in a special organic polymer spinning solution, and then a crude adsorbent is obtained through a wet spinning process, and finally a high-capacity and high-efficiency granulated lithium adsorbent product is obtained through an adsorbent post-treatment process. The special organic polymer spinning solution mainly comprises a substrate (organic polymer skeleton material) with excellent mechanical strength, a highly hydrophilic fragment material, and a key gradient pore forming agent. Therefore, the resin material has high mechanical strength, long cycle life, and high mass transfer efficiency. The high-capacity lithium adsorbent preparation method involved in the present invention is simple, suitable for large-scale production, has positive economic benefits, and is suitable for lithium extraction in industries such as salt lakes, seawater, and lithium resource recovery.

[0008] The technical solution adopted by the present invention is as follows:

[0009] A method for preparing a high-capacity lithium adsorbent comprises the following steps:

[0010] The organic polymer spinning solution is prepared by using organic polymer skeleton material, hydrophilic fragment material, gradient pore former and adsorbent active powder;

[0011] Using organic polymer spinning solution to perform wet spinning to obtain a crude lithium adsorbent;

[0012] The crude lithium adsorbent is post-processed to obtain a finished lithium adsorbent.

[0013] Furthermore, the method of preparing the organic polymer spinning solution by using the organic polymer skeleton material, the hydrophilic segment material, the gradient pore forming agent and the adsorbent active powder comprises:

[0014] Weigh an appropriate amount of polar organic solvent and heat it to 50-80°C;

[0015] The organic polymer skeleton material, the hydrophilic segment material and the gradient pore forming agent are dissolved in an organic solvent, and then the adsorbent active powder is added to obtain an organic polymer spinning solution by fully mixing the materials;

[0016] Among them, the addition amount of organic polymer skeleton material is 5-25% of the sum of the mass of organic polymer skeleton material and adsorbent active powder, the hydrophilic fragment material accounts for 0.2% of the organic polymer skeleton material, the gradient pore former accounts for 40% of the organic polymer skeleton material, and the addition amount of adsorbent active powder is 75-95% of the sum of the mass of organic polymer skeleton material and adsorbent active powder.

[0017] Furthermore, the wet spinning using the organic polymer spinning solution comprises: adding the organic polymer spinning solution to a vacuum degassing kettle for degassing for 10 to 20 minutes, and then performing wet spinning.

[0018] Furthermore, the post-processing of the crude lithium adsorbent comprises:

[0019] The crude lithium adsorbent is immersed in a small molecule alcohol solution containing lithium ions for 8 to 12 hours;

[0020] The soaked lithium adsorbent crude product is granulated, screened and washed in sequence to remove the solvent and the gradient pore forming agent, and the lithium adsorbent finished product is obtained by filtering.

[0021] Furthermore, the organic polymer skeleton material is at least one of polyvinyl chloride, polyvinylidene fluoride, polyether sulfone, polyether ketone, polysulfone, polydimethylsiloxane, and polycarbonate.

[0022] Furthermore, the hydrophilic segment material is at least one of polyacrylonitrile, polyacrylic acid, polyacrylamide, polyvinyl alcohol, and polyurethane.

[0023] Furthermore, the gradient pore forming agent includes the following substances added in equal proportions: toluene, isooctyl alcohol, sodium hexadecyl sulfonate, polyvinyl biethylene, polyvinyl pyrrolidone, polyvinyl alcohol, and inorganic salts.

[0024] Furthermore, the adsorbent active powder is one of aluminum-based adsorbent active powder, titanium-based adsorbent active powder, and manganese-based adsorbent active powder.

[0025] The present invention also provides a high-capacity lithium adsorbent, which is a microsphere with three-dimensional gradient pores and is prepared by the above method.

[0026] The present invention also provides the use of the high-capacity lithium adsorbent in electrodialysis tail liquid or raw halogen.

[0027] Compared with the prior art, the advantages of the present invention are:

[0028] (1) The present invention can solve the problems of low capacity and slow mass transfer rate of traditional lithium adsorbents in the process of lithium extraction by adsorption.

[0029] (2) The lithium adsorbent of the present invention has a high effective active powder loading, so the adsorption capacity is higher than that of traditional adsorbents;

[0030] (3) The lithium adsorbent of the present invention has a three-dimensional gradient pore structure, so the mass transfer rate is faster than that of traditional adsorbents;

[0031] (4) The lithium adsorbent of the present invention has excellent stability and durability, and low operating cost, and is suitable for industrial-scale lithium extraction process.

[0032] (5) The adsorbent of the present invention has a gradient pore size ranging from nanometers to tens of micrometers, and a wide range of pore size distribution, which is conducive to rapid mass transfer. In the post-processing process of the present invention, small molecule alcohols such as propylene glycol are used to keep these pores from being closed or merged, ensuring that the final product can retain the required gradient pore structure. In addition, the large gradient pore structure has good mechanical properties and can withstand large loads, which is suitable for application scenarios requiring high strength and high stiffness. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 .The present invention relates to the preparation steps of the lithium adsorbent.

[0034] Figure 2 .SEM image of the cross section of the finished lithium adsorbent material.

[0035] Figure 3 .The lithium adsorption capacity of the resin of the present invention in the electrodialysis tail liquid.

[0036] Figure 4 .Mass transfer rate of the lithium adsorbent of the present invention in the electrodialysis tail liquid.

[0037] Figure 5 .The lithium adsorption capacity of the resin of the present invention in lithium precipitation mother liquor.

[0038] Figure 6 .Mass transfer rate of the lithium adsorbent of the present invention in raw halogen. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0040] 1. The preparation steps of the high-capacity lithium adsorbent according to the present invention:

[0041] The present invention relates to the preparation of lithium adsorbent microspheres, which mainly includes three steps: preparation of spinning solution, wet spinning and post-treatment of adsorbent crude product. Figure 1The preparation steps will be described in detail one by one below.

[0042] (1) Preparation of spinning solution: Weigh an appropriate amount of polar organic solvent and heat it to 50-80°C, dissolve the organic polymer skeleton material (the amount added is 5-25% of the sum of the mass of the organic polymer skeleton material and the adsorbent active powder), the hydrophilic segment material (accounting for 0.2% of the mass of the organic polymer skeleton material) and the gradient pore forming agent (accounting for 40% of the mass of the organic polymer skeleton material) in the organic solvent, and add the adsorbent active powder (the amount added is 75-95% of the sum of the mass of the organic polymer skeleton material and the adsorbent active powder) after the above materials are completely dissolved. Finally, the spinning solution is obtained by fully mixing.

[0043] (2) Wet spinning: The spinning solution prepared in step (1) is added to a vacuum degassing reactor for degassing (10 to 20 minutes), and then wet spinning is performed to finally obtain a crude lithium adsorbent.

[0044] (3) Post-treatment of crude adsorbent: First, the crude lithium adsorbent obtained in step (2) is completely immersed in a small molecule alcohol solution containing lithium ions for 8 to 12 hours. Secondly, the soaked adsorbent is pelletized, sieved, and washed (to remove the solvent and gradient pore forming agent) in sequence. Finally, the finished lithium adsorbent is obtained by filtration.

[0045] The small molecule alcohol solution is preferably a glycerol aqueous solution, and may also be an aqueous solution of small molecule alcohols such as methanol, ethanol, propanol, butanol, etc. Small molecule alcohols such as glycerol prevent the pores from being destroyed or blocked during the fiber coagulation and subsequent processing, so as to keep the pores from being closed or merged, and ensure that the final product can retain the desired gradient pore structure.

[0046] 2. Structural description of the high-capacity lithium adsorbent of the present invention:

[0047] The lithium adsorbent of the present invention is a microsphere with special three-dimensional gradient pores. The structural design of the resin enables it to have a higher effective active powder loading. In addition, when the adsorbent of the structure contacts with a lithium-containing solution, the active powder in the skeleton material can quickly contact with lithium, so the material can achieve efficient lithium extraction.

[0048] The structural features of the lithium adsorbent of the present invention include:

[0049] (1) Organic framework with high mechanical strength: The lithium adsorbent of the present invention uses an organic polymer with high mechanical strength as the main framework material, so the adsorbent has good chemical stability and mechanical strength.

[0050] (2) Hydrophilic fragments: The lithium adsorbent of the present invention also contains highly hydrophilic fragment materials. These hydrophilic materials can help the interior of the adsorbent to be quickly infiltrated by the lithium-containing solution, thereby achieving rapid mass transfer.

[0051] (3) Three-dimensional gradient pore structure: The three-dimensional gradient pore structure of the lithium adsorbent of the present invention is a special porous material structure, which usually has a pore size and distribution that continuously changes in space (e.g. Figure 2 This structure can provide excellent mechanical properties and functional characteristics.

[0052] (4) High adsorption capacity: The lithium adsorbent of the present invention has a large number of gradient pores, and the effective active powder loading per unit volume of the granulated adsorbent is higher, so the adsorption capacity is higher than that of traditional lithium adsorbents.

[0053] 3. The high-capacity lithium adsorbent of the present invention has high adsorption capacity and rapid adsorption of lithium ions:

[0054] The principle of high adsorption capacity and rapid adsorption of lithium ions by the granulated lithium adsorbent of the present invention mainly involves the following aspects (the active powder of the adsorbent is illustrated by taking aluminum as an example):

[0055] (1) Adsorbent active powder adsorbs Li + Principle: Aluminum-based adsorbents are mainly based on the structure of layered double hydroxides (LDHs). In this structure, the positively charged aluminum oxide octahedron and the Li + The structure is orderly assembled into a stacked structure, which is electrically neutral as a whole. During the adsorption process, lithium ions enter the octahedral cavity in the aluminum hydroxide layer in the form of bare ions and are adsorbed. At the same time, chloride ions enter the interlayer to balance the charge.

[0056] (2) The lithium adsorbent skeleton material of the present invention contains some strongly hydrophilic fragment materials, and the adsorbent has a large number of three-dimensional gradient pore structures. This special structure promotes the rapid diffusion of lithium ions, reduces the mass transfer resistance, makes the adsorption process faster, and thus improves the adsorption efficiency.

[0057] The present invention provides a high-performance lithium adsorbent for salt lakes, the key points of which are as follows:

[0058] 1. The organic polymer skeleton material is any one or more organic polymers with high mechanical strength such as polyvinyl chloride, polyvinylidene fluoride, polyether sulfone, polyether ketone, polysulfone, polydimethylsiloxane, polycarbonate, etc. Including but not limited to the above organic polymers.

[0059] 2. The hydrophilic segment material is any one or more of organic polymers with strong hydrophilicity such as polyacrylonitrile, polyacrylic acid, polyacrylamide, polyvinyl alcohol, polyurethane, etc., including but not limited to the above organic polymers.

[0060] 3. Gradient pore forming agents are: toluene, isooctyl alcohol, sodium hexadecyl sulfonate, polyvinyl (Mn: 800-2w), polyvinyl pyrrolidone (k=30), polyvinyl alcohol (Mn: 2-25w), inorganic salts (KCl, NaCl, MgCl 2 Equal water-soluble salts, particle size of 50 ~ 100μm), all of the above pore formers are added in equal proportions. It should be emphasized that each of the above pore formers can be replaced by agents of equivalent molecular size, including but not limited to the pore formers listed above. The reason why the present invention can form a three-dimensional gradient pore structure is that: during the material preparation process, these pore formers are uniformly dispersed in the organic polymer skeleton material. After spinning and forming, it is immersed in water or other solvents, and the pore formers will dissolve and be removed, leaving pores in the material. The composite pore former used in the present invention can produce pores ranging from several nanometers to tens of microns, so it can eventually form a three-dimensional gradient pore structure.

[0061] 4. The active adsorbent powder required for the preparation of the lithium adsorbent involved in the present invention is any one of aluminum, manganese and titanium. The core lies in the construction of a three-dimensional gradient pore structure, and the gradient pore former is the key.

[0062] Other embodiments of the present invention:

[0063] 1. Preparation Step (1) The mixing method may be mechanical stirring mixing, kneading machine mixing or mixing in an extruder barrel, including but not limited to the above mixing methods.

[0064] 2. The organic solvent in the preparation step (1) is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone and dimethyl sulfoxide, including but not limited to the above organic solvents.

[0065] 3. The granulation method is any one of the phase inversion granulation methods such as wet spinning granulation, pellet granulation or extrusion granulation.

[0066] The technical solution of the present invention will be explained in more detail below. However, it should be understood that within the scope of the present invention, the above-mentioned technical features of the present invention and the technical features specifically described below (such as embodiments) can be combined with each other to form a new or preferred technical solution.

[0067] Example 1. Preparation of high-capacity lithium adsorbent of the present invention

[0068] (1) Weigh 0.5 kg of polyethersulfone, 0.001 kg of polyvinyl alcohol, and 0.2 kg of gradient pore former, and add them to 50°C N,N-dimethylformamide. After they are completely dissolved, 9.5 kg of active powder of aluminum adsorbent is mixed into the above slurry, and stirred at a constant temperature of 50°C for 6 hours to obtain a spinning solution. The gradient pore formers used are: toluene, isooctyl alcohol, sodium hexadecyl sulfonate, polyvinyl divinyl (Mn: 800-2w), polyvinyl pyrrolidone (k=30), polyvinyl alcohol (Mn: 2-25w), and KCl (50-100μm).

[0069] (2) The spinning solution prepared in step (1) is added to a vacuum degassing reactor for degassing for 10 minutes, and then a crude lithium adsorbent is obtained by wet spinning.

[0070] (3) Soaking the crude adsorbent obtained in step (2) in a solution containing Li + The lithium adsorbent is then immersed in a propylene glycol aqueous solution for 8 hours. Next, the lithium adsorbent is pelletized, sieved, washed and filtered to obtain a finished lithium adsorbent. Figure 2 This is the cross-sectional SEM image of the finished lithium adsorbent.

[0071] Example 2. Preparation of high-capacity lithium adsorbent of the present invention

[0072] (1) Add 1.5 kg of polyvinyl chloride, 0.003 kg of polyacrylonitrile, and 0.6 kg of gradient pore former to 65°C N-methylpyrrolidone. After complete dissolution, mix 8.5 kg of aluminum adsorbent active powder into the above slurry and stir at a constant temperature of 50°C for 6 hours to obtain the spinning solution.

[0073] (2) The operation method is the same as step (2) of Example 1, and the degassing time is 15 min.

[0074] (3) The operation method is the same as step (3) of Example 1, and the soaking time is 10 hours.

[0075] Example 3. Preparation of high-capacity lithium adsorbent of the present invention

[0076] (1) Add 2.5 kg of polyvinylidene fluoride, 0.005 kg of polyacrylamide, and 1 kg of gradient pore former into dimethyl sulfoxide at 80°C. After they are completely dissolved, mix 7.5 kg of active powder of aluminum adsorbent into the above slurry, and stir at a constant temperature of 50°C for 6 hours to obtain a spinning solution.

[0077] (2) The operation method is the same as step (2) of Example 1, and the degassing time is 20 min.

[0078] (3) The operation method is the same as step (3) of Example 1, and the soaking time is 12 h.

[0079] Example 4. Application of the high-capacity lithium adsorbent of the present invention in electrodialysis tail liquid

[0080] 300 mL of the lithium adsorbent of the present invention was measured and filled into the chromatography column. The electrodialysis tail liquid (composition see Table 1, pH 5.5) / deionized water (pH adjusted to 5.0) was pumped in from the top and out from the bottom by a constant flow pump. The adsorption time was 90 min, and 4 BV (Bed volume) of brine was fed. The desorption time was 40 min, and 6 BV of water was fed. After the adsorption and desorption were completed, the various components of the tail brine were tested, and the test results are shown in Table 2. The lithium adsorption capacity data is shown in Table 2. Figure 3 The results show that within 15 cycles of the test, the adsorption capacity of the lithium adsorbent of the present invention is 3.75 g / L on average, with a low impurity content, while the adsorption capacity of the conventional lithium adsorbent in the electrodialysis tail liquid is 3.23 g / L on average. This experiment shows that the adsorption capacity of the lithium adsorbent of the present invention is much higher than that of the conventional lithium adsorbent. Figure 4 is the mass transfer rate of the lithium adsorbent of the present invention in the desorption stage and the adsorption stage in the electrodialysis tail liquid. It can be seen that the adsorption and desorption rates of the lithium adsorbent of the present invention are faster than those of the traditional lithium adsorbent, that is, the lithium adsorbent of the present invention consumes less fresh water when applied industrially, and the qualified liquid concentration is higher, and the energy consumption of the post-treatment process is low.

[0081] Table 1. Electrodialysis tail liquid brine components of a salt lake enterprise in Qinghai

[0082] Components Li Na K Ca Mg B <![CDATA[SO 4 2- ]]> Cl Concentration (g / L) 0.64 0.58 0.15 0.06 52.19 3.50 16.78 0.16

[0083] Table 2. Composition of qualified liquid after treatment with lithium adsorbent of the present invention

[0084] Components Li Na K Ca Mg B <![CDATA[SO 4 2- ]]> Cl Concentration (g / L) 1.39 0.04 0.01 0.001 0.22 0.16 0.08 0.02

[0085] Example 5. Application of the high-capacity lithium adsorbent of the present invention in raw halogen

[0086] 300 mL of the lithium adsorbent of the present invention was measured and filled into the chromatography column. The original brine (composition is shown in Table 3, pH 5.5) / deionized water (pH 5.0) was pumped in from the top and out from the bottom by a constant flow pump. The adsorption time was 90 min, and the brine input was 4.5 BV (Bed volume). The desorption time was 40 min, and the water input was 6.4 BV. After the adsorption and desorption were completed, the ICP test of each component of the tail brine was performed. The test results are shown in Table 4. The lithium adsorption capacity data is shown in Table 4. Figure 5 The results show that the average adsorption capacity of the lithium adsorbent of the present invention is 3.76 g / L, while the average adsorption capacity of the conventional resin in raw brine is 3.21 g / L. This experiment once again proves that the lithium adsorbent of the present invention has a higher adsorption capacity. Figure 6It is the mass transfer rate of the lithium adsorbent of the present invention in the raw halide. It can be seen that in the complex environment with high concentration of impurity ions, the mass transfer rate of the lithium adsorbent of the present invention is still faster.

[0087] Table 3. Composition of raw brine from a salt lake enterprise in Qinghai

[0088] Components Li Mg B <![CDATA[SO 4 2- ]]> K Na Ca Cl Concentration (g / L) 0.51 17.41 0.76 50.52 11.88 102.50 0.18 0.18

[0089] Table 4. Composition of qualified liquid after the original halogen table was treated with the lithium adsorbent of the present invention

[0090] Components Li Mg B <![CDATA[SO 4 2- ]]> K Na Ca Cl Concentration (g / L) 1.44 0.11 0.32 0.04 0.01 0.15 0.003 0.004

[0091] The specific embodiments of the present invention disclosed above are intended to help understand the content of the present invention and implement it accordingly. It can be understood by those skilled in the art that various replacements, changes and modifications are possible without departing from the spirit and scope of the present invention. The present invention should not be limited to the contents disclosed in the embodiments of this specification, and the scope of protection of the present invention shall be subject to the scope defined in the claims.

Claims

1. A method for preparing a high-capacity lithium adsorbent, characterized in that: The following steps are involved: The organic polymer spinning solution is prepared by using organic polymer skeleton material, hydrophilic fragment material, gradient pore former and adsorbent active powder; Using organic polymer spinning solution to perform wet spinning to obtain a crude lithium adsorbent; The crude lithium adsorbent is post-processed to obtain a finished lithium adsorbent.

2. The method according to claim 1, characterized in that The method of preparing the organic polymer spinning solution by using the organic polymer skeleton material, the hydrophilic segment material, the gradient pore forming agent and the adsorbent active powder comprises: Weigh an appropriate amount of polar organic solvent and heat it to 50-80°C; The organic polymer skeleton material, the hydrophilic segment material and the gradient pore forming agent are dissolved in an organic solvent, and then the adsorbent active powder is added to obtain an organic polymer spinning solution by fully mixing the materials; Among them, the addition amount of organic polymer skeleton material is 5-25% of the sum of the mass of organic polymer skeleton material and adsorbent active powder, the hydrophilic fragment material accounts for 0.2% of the organic polymer skeleton material, the gradient pore former accounts for 40% of the organic polymer skeleton material, and the addition amount of adsorbent active powder is 75-95% of the sum of the mass of organic polymer skeleton material and adsorbent active powder.

3. The method according to claim 1, characterized in that The wet spinning using organic polymer spinning stock solution comprises: adding the organic polymer spinning stock solution to a vacuum degassing kettle for degassing for 10 to 20 minutes, and then performing wet spinning.

4. The method according to claim 1, characterized in that: The post-processing of the crude lithium adsorbent comprises: The crude lithium adsorbent is immersed in a small molecule alcohol solution containing lithium ions for 8 to 12 hours; The soaked lithium adsorbent crude product is granulated, screened and washed in sequence to remove the solvent and the gradient pore forming agent, and the lithium adsorbent finished product is obtained by filtering.

5. The method according to claim 1, characterized in that: The organic polymer skeleton material is at least one of polyvinyl chloride, polyvinylidene fluoride, polyether sulfone, polyether ketone, polysulfone, polydimethylsiloxane, and polycarbonate.

6. The method according to claim 1, characterized in that The hydrophilic segment material is at least one of polyacrylonitrile, polyacrylic acid, polyacrylamide, polyvinyl alcohol and polyurethane.

7. The method according to claim 1, characterized in that The gradient pore forming agent includes the following substances added in equal proportions: toluene, isooctyl alcohol, sodium hexadecyl sulfonate, polyvinyl biethylene, polyvinyl pyrrolidone, polyvinyl alcohol, and inorganic salt.

8. The method according to claim 1, characterized in that The active adsorbent powder is one of aluminum-based active adsorbent powder, titanium-based active adsorbent powder and manganese-based active adsorbent powder.

9. A high-capacity lithium adsorbent, characterized in that: The high-capacity lithium adsorbent is a microsphere with three-dimensional gradient pores, and is prepared by the method described in any one of claims 1 to 8.

10. Use of the high-capacity lithium adsorbent according to claim 9 in electrodialysis tail liquid or raw brine.

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