Granular manganese lithium ion sieve and cross-linking granulation forming method thereof

Abstract

The invention provides a granular manganese lithium ion sieve and a cross-linking granulation forming method thereof, and the method comprises the following steps: carrying out surface modification on manganese lithium ion sieve powder to obtain a modified manganese lithium ion sieve; the preparation method comprises the following steps: adding a hydrophobic polymer binder, a hydrophilic cross-linking agent, a modified manganese lithium ion sieve, a cross-linking aid and a pore-foaming agent into a solvent to obtain premixed slurry A; pre-crosslinking the pre-mixed slurry A, dropwise adding the pre-crosslinked pre-mixed slurry A into deionized water to form spheres, curing in the soaking process, removing the solvent and the pore-foaming agent, and finally washing and drying the spheres to obtain pre-crosslinked particles B; and carrying out deep crosslinking on the pre-crosslinked particles B to obtain the granular manganese lithium ion sieve. According to the application, the manganese lithium ion sieve is firstly modified by the silane coupling agent, and the porosity and the network strength are precisely regulated and controlled by adopting the hydrophobic polymer binder, the hydrophilic crosslinking agent and the pre-crosslinking sizing-deep crosslinking strengthening process, so that the hydrophilicity and the adsorption kinetics of the particles are improved, and the high adsorption performance and the stability of the particles are balanced.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion sieve production technology, specifically relating to a granular manganese-based lithium-ion sieve and its cross-linking granulation molding method. Background Technology

[0002] With the rapid development of the new energy industry, lithium resources, as a key raw material in core fields such as power batteries and energy storage equipment, are experiencing a continuous rise in strategic value and market demand. How to efficiently extract lithium from liquid lithium resources such as salt lake brine and leachate from spent lithium batteries has become a critical problem that urgently needs to be solved. Among existing lithium extraction technologies, manganese-based lithium-ion sieves have become ideal lithium extraction materials due to their high selectivity and excellent adsorption performance.

[0003] However, manganese-based lithium ion sieves are usually in the form of micron or even nano-sized powders, which are easily lost during actual adsorption-desorption cycles, leading to material loss and water pollution. Furthermore, solid-liquid separation of powders requires supporting filtration equipment, which increases industrial costs. Therefore, they must be prepared into specific shapes through molding processes to meet the needs of industrial applications.

[0004] Granulation is a common method for forming lithium-ion sieves. It mainly involves encapsulating the lithium-ion sieve with a binder and then solidifying it. Based on the preparation method, it is mainly divided into physical encapsulation and suspension polymerization. Physical encapsulation is the primary method due to its simplicity, but it has significant drawbacks: the lithium-ion sieve and the binder surface lack effective chemical interaction; during the adsorption-desorption cycle, the poor compatibility between the powder and the binder easily leads to interfacial detachment; and the dense binder coating physically shields adsorption sites, resulting in a significant decrease in adsorption capacity. Chinese patent CN119114005A discloses a porous lithium metatitanate lithium-ion sieve, which uses styrene monomer, divinylbenzene crosslinking agent, initiator, and pore-forming agent to granulate the lithium-ion sieve through suspension polymerization. The lithium-ion sieve particles prepared by this invention solve the problems of high dissolution loss and difficult filtration of powdered lithium-ion sieves, but their adsorption capacity is low.

[0005] Existing granulation technologies for lithium-ion sieves struggle to balance powder immobilization and high adsorption performance, hindering their efficient application in lithium resource recovery. Therefore, improving granulation technology to maintain the original adsorption performance of lithium-ion sieves remains a key challenge in the field. Summary of the Invention

[0006] To address the shortcomings of existing technologies, such as powder loss and low adsorption capacity, and to achieve a balance between powder fixation and high adsorption performance, this application first proposes a cross-linking granulation method for granular manganese-based lithium ion sieves, which includes the following steps:

[0007] (1) Silane coupling agent is used to modify the surface of manganese lithium ion sieve powder to graft reactive groups onto the surface of manganese lithium ion sieve to obtain modified manganese lithium ion sieve.

[0008] (2) Add hydrophobic polymer binder, hydrophilic crosslinking agent, modified manganese lithium ion sieve, crosslinking aid and pore-forming agent to solvent, mix evenly to obtain premixed slurry A;

[0009] (3) Premixed slurry A is placed in a constant temperature water bath for pre-crosslinking to obtain pre-crosslinked slurry. The pre-crosslinked slurry is dropped into deionized water to form spheres. The spheres are then soaked in deionized water, cured and the solvent and pore-forming agent are removed. The spheres are then washed and dried to constant weight to obtain pre-crosslinked particles B.

[0010] (4) The pre-crosslinked particles B are deeply crosslinked under vacuum to obtain granular manganese lithium ion sieve.

[0011] Specifically, the manganese-based lithium ion sieve is HMn2O4, H 1.6 Mn 1.6 O4, H4Mn5O 12 One or more of them.

[0012] This application first modifies the manganese-based lithium-ion sieve using a silane coupling agent, grafting epoxy groups onto its surface. These epoxy groups can undergo ring-opening reactions with the amino groups of the hydrophilic crosslinking agent, forming chemical bonds and enhancing the interfacial bonding between the lithium-ion sieve and the binder, thus facilitating the effective fixation of the lithium-ion sieve powder. Furthermore, a hydrophobic polymer binder and a hydrophilic crosslinking agent are used to fix the powdered lithium-ion sieve and improve the hydrophilicity of the particles, thereby enhancing their adsorption kinetics. A pre-crosslinking shaping-deep crosslinking strengthening process is employed, allowing the pore-forming agent to volatilize during crosslinking, precisely controlling porosity and network strength, ensuring both high adsorption performance and balanced stability. The granular manganese-based lithium-ion sieve prepared using this application maintains an equilibrium adsorption capacity above 31.6 mg / g, with a powder loss rate controlled below 0.4%.

[0013] Specifically, in step (1), the surface modification of the manganese-based lithium ion sieve powder includes the following steps:

[0014] First, the manganese-based lithium ion sieve powder is added to an ethanol aqueous solution and stirred, and then ultrasonically dispersed to obtain a powder solution;

[0015] Then, the silane coupling agent is added to the powder solution to form a coupling agent mixture. The coupling agent mixture is heated to 50~70℃ and stirred for 1~3 hours to obtain a suspension.

[0016] The suspension was filtered, the filter residue was washed with ethanol, and after drying, a modified manganese-based lithium-ion sieve with surface-grafted epoxy groups was obtained.

[0017] Specifically, the concentration of manganese-based lithium ion sieve powder in the powder solution is 15~30g / L; the drying of the filter residue is carried out under vacuum conditions with an absolute pressure of 800~1500Pa, a drying temperature of 70~90℃, and a drying time of 4~7h.

[0018] Preferably, the ethanol aqueous solution is formed by anhydrous ethanol and water in a volume ratio of (2~4):1, the silane coupling agent is KH-560, and the amount of silane coupling agent is 2~5% of the mass of the manganese-based lithium ion sieve powder.

[0019] The amount of alkyl coupling agent used will affect the grafting rate of epoxy groups in the lithium-ion screen, thus affecting the interfacial bonding force between the lithium-ion screen and the hydrophobic polymer binder. If the amount of alkyl coupling agent used is relatively small, the grafting rate will be too low, and it will not be able to fully react with the amino groups of the hydrophilic crosslinking agent, resulting in weak interfacial bonding force. If the amount of alkyl coupling agent used is too large, the excess alkyl coupling agent will agglomerate on the surface of the lithium-ion screen, affecting the uniformity of crosslinking.

[0020] Preferably, the amount of solvent is 3 to 5 times the total mass of the hydrophobic polymer binder, the hydrophilic crosslinking agent, and the modified manganese lithium-ion sieve; the mass ratio of the hydrophobic polymer binder to the hydrophilic crosslinking agent is 1:(0.2 to 2); the mass ratio of the total mass of the hydrophobic polymer binder and the hydrophilic crosslinking agent to the mass of the modified manganese lithium-ion sieve is 1:(1 to 3); the mass of the crosslinking aid is 3 to 5% of the total mass of the hydrophobic polymer binder and the hydrophilic crosslinking agent; and the mass of the pore-forming agent is 5 to 8% of the mass of the premixed slurry A.

[0021] The amount of solvent used affects the viscosity of premixed slurry A. Controlling the viscosity of premixed slurry A within a certain range ensures its flowability for subsequent dripping and allows it to quickly solidify after being added to deionized water. If the viscosity of premixed slurry A is too high, it cannot form droplets during dripping and instead forms a continuous line. If the viscosity of premixed slurry A is too low, although dripping is possible, the solidification speed in deionized water decreases, causing droplets to clump together and fail to form droplets. In severe cases, this can lead to the formation of a large lump of premixed slurry A in deionized water.

[0022] The mass ratio of hydrophobic polymer binder to hydrophilic crosslinking agent affects the hydrophilicity and mechanical strength of granular manganese lithium ion sieves. If the proportion of hydrophilic crosslinking agent is too low, the hydrophilicity of the granular manganese lithium ion sieve will not be significantly improved. If the proportion of hydrophilic crosslinking agent is too high, it will easily cause phase separation of the hydrophobic polymer binder, resulting in a decrease in the mechanical properties and poor stability of the prepared granular manganese lithium ion sieve.

[0023] The amount of pore-forming agent added affects the porosity of granular manganese-based lithium-ion sieves. When the amount of pore-forming agent is 5-8%, the particles form an interconnected pore structure, which can shorten the Li-ion sieve's lifespan.+ The diffusion path of Li + It can reach the adsorption site more quickly, thereby improving adsorption kinetics; when the amount of pore-forming agent is >8%, excessive pore connectivity will lead to a decrease in the strength of granular manganese lithium ion sieves, and lithium ion sieve powder will easily fall off and be lost during adsorption.

[0024] Specifically, in step (2), the solvent is one or a mixture of two of N,N-dimethylformamide, N,N-dimethylacetamide, or tetrahydrofuran; the hydrophobic polymeric binder is polyvinyl chloride; the hydrophilic crosslinking agent is polyethyleneimine, with a number average molecular weight of 600-10000; and the porogen is polyethylene glycol 400. The degree of polymerization of polyvinyl chloride is 600-800.

[0025] Polyethyleneimine, as a hydrophilic crosslinking agent, possesses amino groups that improve hydrophilicity, thereby enhancing the wettability of the prepared granular manganese-based lithium ion sieve. During adsorption, this increases the effective contact area between the granular manganese-based lithium ion sieve and the lithium-containing solution, which is beneficial for improving its adsorption capacity and adsorption rate. Furthermore, the amino groups undergo nucleophilic substitution reactions with the chlorine atoms of polyvinyl chloride to form a three-dimensional network structure that encapsulates and fixes the manganese-based lithium ion sieve. The amino groups can also chemically anchor the epoxy groups on the surface of the modified manganese-based lithium ion sieve, further immobilizing it.

[0026] The degree of polymerization of polyvinyl chloride (PVC) and the molecular weight of polyethyleneimine affect the crosslinking density of premixed slurry A. Under the above constraints, polyethyleneimine can react simultaneously with the epoxy groups of the lithium-ion sieve and the chlorine atoms of PVC to form a complete crosslinked network that fixes the lithium-ion sieve. If the molecular weight of polyethyleneimine is too high, it can easily lead to an increase in the viscosity of the system, making granulation difficult. Furthermore, using PVC with the above-mentioned degree of polymerization ensures its solubility and also allows for the formation of a uniform crosslinked network when PVC reacts with polyethyleneimine.

[0027] Preferably, in step (2), the crosslinking aid is a composite catalyst composed of triethylamine and potassium iodide, wherein the mass ratio of triethylamine to potassium iodide in the composite catalyst is (3~5):1.

[0028] Using the aforementioned composite catalyst as a crosslinking aid can improve the crosslinking rate and degree of crosslinking between polyvinyl chloride (PVC) and polyethyleneimine (PEI). Triethylamine, as a nucleophilic substitution catalyst, can neutralize the HCl generated during the crosslinking of PVC and PEI, preventing the protonation of PEI and subsequent deactivation. The I in potassium iodide... - Cl in polyvinyl chloride - Replace with a more active I - It activates chlorine atoms, making it easier for the amino group of polyethyleneimine to attack.

[0029] Specifically, in step (2), the preparation of premixed slurry A is carried out in the following steps: First, the hydrophilic crosslinking agent is dissolved in the solvent. After the hydrophilic crosslinking agent is completely dissolved, the hydrophobic polymer binder and pore-forming agent are added. After the hydrophobic polymer binder and pore-forming agent are completely dissolved, the modified manganese lithium ion sieve is added and stirred evenly. Finally, the crosslinking aid is added and stirred evenly.

[0030] First, dissolve the polyethyleneimine, which acts as a hydrophilic crosslinking agent, to ensure that the reaction sites (amino groups) are evenly distributed in the system. If it is added simultaneously with solid components such as hydrophobic polymer binders (polyvinyl chloride) and modified manganese-based lithium ion sieves, the dissolution may be hindered due to the adsorption of solvent by solid particles, forming locally undissolved polyethyleneimine aggregates. This can easily lead to defects such as excessive or uncrosslinked areas during subsequent crosslinking with polyvinyl chloride.

[0031] Subsequently, a hydrophobic polymeric binder (polyvinyl chloride) and a porogen are added simultaneously. This simultaneous dissolution allows the porogen to penetrate the polyvinyl chloride molecular chains, reducing intermolecular forces, accelerating the dissolution of polyvinyl chloride, and forming a homogeneous solution. This avoids the increase in system viscosity caused by the preferential dissolution of polyvinyl chloride, which could lead to the aggregation of the porogen. Uniform dispersion of the porogen is beneficial for subsequent cross-linking and antisolvent precipitation, as it allows the porogen to form uniform, interconnected pores, preventing uneven porosity or closed pores.

[0032] After the added components have completely dissolved, the modified manganese-based lithium ion sieve is added. The epoxy groups on the surface of the modified manganese-based lithium ion sieve can fully contact the uniformly dispersed polyethyleneimine amino groups to ensure the bonding force between the lithium ion sieve and other components.

[0033] Finally, a crosslinking aid (composite catalyst) is added. At this point, all components in the system are in a homogeneous state and the lithium-ion sieve powder is evenly dispersed. Starting the crosslinking reaction at this point ensures that the reaction proceeds synchronously throughout the entire system, avoiding excessive local crosslinking that forms gel blocks or insufficient crosslinking that causes the powder to easily fall off.

[0034] Specifically, in the preparation process of premixed slurry A, the temperature of the solution is maintained at 40~60℃ to ensure that the hydrophobic polymer binder, hydrophilic crosslinking agent, crosslinking aid and pore-forming agent are completely dissolved and well dispersed, which facilitates subsequent pre-crosslinking.

[0035] Preferably, in order to ensure the quality of crosslinking, in step (3), the pre-crosslinking temperature is 80~90℃ and the pre-crosslinking time is 4~6h; the sphere is soaked in deionized water for 1~2h and the soaking temperature is 40~60℃; the drying temperature of the sphere is 60~80℃.

[0036] Preferably, in step (4), the deep crosslinking temperature is 100~120℃, the deep crosslinking time is 1~2h, and the vacuum degree is 800~1500Pa.

[0037] Secondly, this application also discloses granular manganese-based lithium-ion sieves prepared using any of the above-described cross-linking granulation molding methods.

[0038] This invention employs a stepwise crosslinking method. Pre-crosslinking initially forms a uniform crosslinking network, while deep crosslinking strengthens the crosslinking network. Simultaneously, during the crosslinking process, the volatilization of the pore-forming agent synergistically regulates the porosity and network strength, thus fixing the lithium-ion sieve powder while ensuring its adsorption activity.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] (1) The cross-linking granulation molding method of the present invention modifies the surface of the lithium ion screen by using an alkyl coupling agent, introduces epoxy groups, enhances the chemical bond between the lithium ion screen and the binder, and thus improves the problem of powder loss.

[0041] (2) The present invention uses hydrophobic polymer binder and hydrophilic crosslinking agent. The hydrophobic polymer binder participates in crosslinking through nucleophilic substitution reaction, giving the network excellent mechanical strength and resistance to acid and alkali corrosion. The amino group of the hydrophilic crosslinking agent not only anchors the lithium ion sieve through chemical action and effectively fixes the lithium ion sieve, but also improves the hydrophilicity of the particles and greatly improves the adsorption kinetics of the particles.

[0042] (3) The present invention adopts a method of pre-crosslinking shaping-deep crosslinking strengthening, and volatilizing the pore-forming agent during the crosslinking process to precisely control the porosity and network strength, which ensures both the high adsorption performance of the particles and the balance of stability. Attached Figure Description

[0043] Figure 1 The change in contact angle of the granular manganese-based lithium ion sieve prepared in Example 1 within 2 minutes.

[0044] Figure 2 This is a SEM image of the surface of the granular manganese-based lithium ion sieve prepared in Example 1.

[0045] Figure 3 This is a SEM image of the cross-section of the granular manganese-based lithium ion sieve prepared in Example 1.

[0046] Figure 4 This is a SEM image of the cross-section of the granular manganese-based lithium ion sieve prepared in Example 2.

[0047] Figure 5 This is a SEM image of the cross-section of the granular manganese-based lithium ion sieve prepared in Example 3.

[0048] Figure 6 This is a SEM image of the surface of the granular manganese-based lithium ion sieve prepared in Example 4.

[0049] Figure 7This is a SEM image of the surface of the granular manganese-based lithium ion sieve prepared in Example 5.

[0050] Figure 8 The image shows a cross-sectional SEM image of the granular manganese-based lithium ion sieve prepared in Comparative Example 1.

[0051] Figure 9 The image shows a cross-sectional SEM image of the granular manganese-based lithium ion sieve prepared in Comparative Example 2.

[0052] Figure 10 The image shows a cross-sectional SEM image of the granular manganese-based lithium ion sieve prepared in Comparative Example 3.

[0053] Figure 11 The image shows a cross-sectional SEM image of the granular manganese-based lithium ion sieve prepared in Comparative Example 4.

[0054] Figure 12 The image shows a cross-sectional SEM image of the granular manganese-based lithium ion sieve prepared in Comparative Example 5.

[0055] Figure 13 The image shows a cross-sectional SEM image of the granular manganese-based lithium ion sieve prepared in Comparative Example 6.

[0056] Figure 14 The image shows a cross-sectional SEM image of the granular manganese-based lithium ion sieve prepared in Comparative Example 7.

[0057] Figure 15 This is a comparison graph of the adsorption capacity of each embodiment and the comparative example. Detailed Implementation

[0058] Example 1

[0059] (1) 10g of manganese-based lithium ion sieve powder was added to 500mL of ethanol-water solution (the volume ratio of anhydrous ethanol to water was 3:1), and ultrasonicated for 30min to disperse the manganese-based lithium ion sieve powder, thereby obtaining a powder solution. Then, 0.35g of KH-560 was added to the powder solution, and the mixture was stirred at 60℃ for 2h to obtain a suspension. In this embodiment, the manganese-based lithium ion sieve powder specifically used was HMn4O5 lithium ion sieve.

[0060] After filtering the suspension, the filter residue was washed three times with anhydrous ethanol, filtered again, and dried at a vacuum of 1000 Pa and a temperature of 80 °C for 5 hours to obtain a modified manganese lithium ion sieve with surface-grafted epoxy groups.

[0061] (2) 1g of PEI (number average molecular weight 1800) was added to 30mL of N,N-dimethylacetamide and completely dissolved. Then, 2g of polyvinyl chloride with a degree of polymerization of 700 and 2.4g of polyethylene glycol 400 were added. After the polyvinyl chloride and polyethylene glycol 400 were completely dissolved, 6g of modified manganese-based lithium ion sieve was added. The mixture was stirred at 50℃ for 1.5h, and then 0.15g of composite catalyst was added. The mixture was stirred for another 30min to obtain premixed slurry A. The composite catalyst was composed of triethylamine and potassium iodide in a mass ratio of 4:1.

[0062] (3) Place the premixed slurry A in an 85°C constant temperature water bath and stir for 4 hours. Use a syringe to drop the premixed slurry A into 40°C deionized water to form spheres. Continue to soak the spheres in deionized water for 1 hour to solidify and remove solvent and pore-forming agent. Then filter out the spheres, wash them 3 times with deionized water, and dry them in a 70°C forced-air drying oven until constant weight to obtain pre-crosslinked particles B.

[0063] (4) Transfer the pre-crosslinked particles B to a vacuum drying oven and perform deep crosslinking for 1 hour under a vacuum of 1000 Pa and a temperature of 100 °C. Then cool to room temperature to obtain 1# granular manganese lithium ion sieve.

[0064] The contact angle of the No. 1 granular manganese-based lithium ion sieve obtained in this embodiment was measured, and the results are as follows: Figure 1 As shown in the figure, the contact angle decreased from 79.3° to 20.8° within 2 minutes, indicating that the No. 1 granular manganese lithium ion sieve has good hydrophilicity. This suggests that the crosslinking of polyethyleneimine and polyvinyl chloride introduces a large number of hydrophilic groups, effectively improving the hydrophilicity of the particles and increasing the effective contact area between the granular manganese lithium ion sieve and the lithium-containing solution, which is beneficial to improving its adsorption capacity and adsorption rate.

[0065] The surface and cross-section of the No. 1 granular manganese-based lithium ion sieve obtained in this embodiment were scanned to obtain... Figure 2 and Figure 3 The SEM image shown, in which Figure 2 Here is a SEM image of the surface. Figure 3 This is a SEM image of the cross-section. From Figure 3 It can be seen that the No. 1 granular manganese-based lithium ion sieve exhibits a three-dimensional network structure, which is formed by cross-linking of polyvinyl chloride and polyethyleneimine. Compared with the subsequent comparative examples 1-7, Figure 3 The observation of a uniform and complete cross-linked network indicates that polyethyleneimine and polyvinyl chloride are fully cross-linked, effectively immobilizing the lithium-ion sieve. Figure 2 It can be seen that the surface of the No. 1 granular manganese-based lithium ion sieve has pores of moderate size. These pores form interconnected channels with the internal network structure, which are conducive to the production of lithium ions. + The diffusion provides channels, exposing more adsorption sites, allowing Li to...+ It can quickly reach the adsorption site, thereby improving adsorption kinetics and adsorption capacity.

[0066] Example 2

[0067] (1) 10g of manganese-based lithium ion sieve powder was added to 650mL of ethanol-water solution (the volume ratio of anhydrous ethanol to water was 3:1), and ultrasonicated for 30min to disperse the manganese-based lithium ion sieve powder to obtain a powder solution. Then, 0.21g of KH-560 was added to the powder solution, and the mixture was stirred at 70℃ for 1.5h to obtain a suspension. In this embodiment, the manganese-based lithium ion sieve powder specifically used was HMn4O5 lithium ion sieve.

[0068] After filtering the suspension, the filter residue was washed three times with anhydrous ethanol, filtered again, and dried at a vacuum of 1500 Pa and a temperature of 85 °C for 4 hours to obtain a modified manganese lithium ion sieve with surface-grafted epoxy groups.

[0069] (2) 0.5 g of PEI (number average molecular weight 600) was added to 30 mL of N,N-dimethylacetamide and completely dissolved. Then, 2.5 g of polyvinyl chloride with a degree of polymerization of 700 and 2.4 g of polyethylene glycol 400 were added. After the polyvinyl chloride and polyethylene glycol 400 were completely dissolved, 6 g of modified manganese-based lithium ion sieve was added. The mixture was stirred at 50 °C for 1.5 h. Then, 0.15 g of composite catalyst was added and the mixture was stirred for another 30 min to obtain premixed slurry A. The composite catalyst was composed of triethylamine and potassium iodide in a mass ratio of 3:1.

[0070] (3) Place the premixed slurry A in an 80°C constant temperature water bath and stir for 5 hours. Use a syringe to drop the premixed slurry A into 50°C deionized water to form spheres. Continue to soak the spheres in deionized water for 2 hours to solidify and remove solvent and pore-forming agent. Then filter out the spheres, wash them 3 times with deionized water, and dry them in a 70°C forced-air drying oven until constant weight to obtain pre-crosslinked particles B.

[0071] (4) Transfer the pre-crosslinked particles B to a vacuum drying oven and perform deep crosslinking for 2 hours under a vacuum of 1200 Pa and a temperature of 120 °C. Then cool to room temperature to obtain 2# granular manganese lithium ion sieve.

[0072] The No. 2 granular manganese-based lithium ion sieve obtained in this embodiment was scanned to obtain the following results: Figure 4 The SEM image shown. (By...) Figure 4 It can be seen that the prepared No. 2 granular manganese lithium ion sieve has a cross-linked network structure, but some networks are starting to become incomplete, which may be due to the relatively small amount of polyethyleneimine used.

[0073] Example 3

[0074] (1) 10g of manganese-based lithium ion sieve powder was added to 350mL of ethanol-water solution (the volume ratio of anhydrous ethanol to water was 4:1), and ultrasonicated for 30min to disperse the manganese-based lithium ion sieve powder, thereby obtaining a powder solution. Then, 0.4g of KH-560 was added to the powder solution, and the mixture was stirred at 50℃ for 3h to obtain a suspension. In this embodiment, the manganese-based lithium ion sieve powder specifically used was HMn4O5 lithium ion sieve.

[0075] After filtering the suspension, the filter residue was washed three times with anhydrous ethanol, filtered again, and dried at a vacuum of 800 Pa and a temperature of 70 °C for 6 hours to obtain a modified manganese lithium ion sieve with surface-grafted epoxy groups.

[0076] (2) 2g of PEI (number average molecular weight 10000) was added to 40mL of N,N-dimethylacetamide and completely dissolved. Then, 1g of polyvinyl chloride with a degree of polymerization of 700 and 3.8g of polyethylene glycol 400 were added. After the polyvinyl chloride and polyethylene glycol 400 were completely dissolved, 6g of modified manganese-based lithium ion sieve was added. The mixture was stirred at 50℃ for 1.5h, and then 0.12g of composite catalyst was added. The mixture was stirred for another 30min to obtain premixed slurry A. The composite catalyst was composed of triethylamine and potassium iodide in a mass ratio of 5:1.

[0077] (3) Place the premixed slurry A in a 90℃ constant temperature water bath and stir for 4 hours. Use a syringe to drop the premixed slurry A into 60℃ deionized water to form spheres. Continue to soak the spheres in deionized water for 1 hour to solidify and remove solvent and pore-forming agent. Then filter out the spheres, wash them 3 times with deionized water, and put them into an 80℃ forced-air drying oven to dry to constant weight to obtain pre-crosslinked particles B.

[0078] (4) Transfer the pre-crosslinked particles B to a vacuum drying oven and perform deep crosslinking for 1.5 h in an environment with a vacuum degree of 800 Pa and a temperature of 110 °C. Then cool to room temperature to obtain No. 3 granular manganese lithium ion sieve.

[0079] The No. 3 granular manganese-based lithium ion sieve obtained in this embodiment was scanned to obtain the following results: Figure 5 The SEM image shown. (By...) Figure 5 It can be seen that the cross-linked network structure inside the No. 3 granular manganese lithium ion sieve begins to increase. This may be because the amount of polyethyleneimine used is relatively large, and local phase separation begins to occur during the cross-linking process, which affects the fixation of the lithium ion sieve powder and increases the instability of the particle structure.

[0080] Example 4

[0081] (1) 10g of manganese-based lithium ion sieve powder was added to 400mL of ethanol-water solution (the volume ratio of anhydrous ethanol to water was 3.5:1), and ultrasonicated for 30min to disperse the manganese-based lithium ion sieve powder, thereby obtaining a powder solution. Then, 0.45g of KH-560 was added to the powder solution, and the mixture was stirred at 65℃ for 2h to obtain a suspension. In this embodiment, the manganese-based lithium ion sieve powder specifically used was HMn4O5 lithium ion sieve.

[0082] After filtering the suspension, the filter residue was washed three times with anhydrous ethanol, filtered again, and dried at a vacuum of 900 Pa and a temperature of 90 °C for 4 hours to obtain a modified manganese lithium ion sieve with surface-grafted epoxy groups.

[0083] (2) 1g of PEI (number average molecular weight 1800) was added to 30mL of N,N-dimethylacetamide and completely dissolved. Then, 2g of polyvinyl chloride with a degree of polymerization of 700 and 2g of polyethylene glycol 400 were added. After the polyvinyl chloride and polyethylene glycol 400 were completely dissolved, 6g of modified manganese-based lithium ion sieve was added. The mixture was stirred at 50℃ for 1.5h, and then 0.15g of composite catalyst was added. The mixture was stirred for another 30min to obtain premixed slurry A. The composite catalyst was composed of triethylamine and potassium iodide in a mass ratio of 4:1.

[0084] (3) Place the premixed slurry A in an 85°C constant temperature water bath and stir for 6 hours. Use a syringe to drop the premixed slurry A into 50°C deionized water to form spheres. Continue to soak the spheres in deionized water for 1.5 hours to solidify and remove solvent and pore-forming agent. Then filter out the spheres, wash them 3 times with deionized water, and dry them in a 60°C forced-air drying oven until constant weight to obtain pre-crosslinked particles B.

[0085] (4) Transfer the pre-crosslinked particles B to a vacuum drying oven and perform deep crosslinking for 1 hour under a vacuum of 1300 Pa and a temperature of 115 °C. Then cool to room temperature to obtain 4# granular manganese lithium ion sieve.

[0086] The No. 4 granular manganese-based lithium ion sieve obtained in this embodiment was scanned to obtain the following results: Figure 6 The SEM image shown. (By...) Figure 6 It can be seen that the surface porosity of the No. 4 granular manganese lithium ion screen is reduced, which may be because the amount of polyethylene glycol 400 added is too small, thus reducing the porosity improvement effect.

[0087] Example 5

[0088] (1) 10g of manganese-based lithium ion sieve powder was added to 350mL of ethanol-water solution (the volume ratio of anhydrous ethanol to water was 2.5:1), and ultrasonicated for 30min to disperse the manganese-based lithium ion sieve powder to obtain a powder solution. Then, 0.5g of KH-560 was added to the powder solution, and the mixture was stirred at 55℃ for 2.5h to obtain a suspension. In this embodiment, the manganese-based lithium ion sieve powder specifically used was HMn4O5 lithium ion sieve.

[0089] After filtering the suspension, the filter residue was washed three times with anhydrous ethanol, filtered again, and dried at a vacuum of 1200 Pa and a temperature of 80 °C for 4.5 h to obtain a modified manganese lithium ion sieve with surface grafted epoxy groups.

[0090] (2) 1g of PEI (number average molecular weight 1800) was added to 30mL of N,N-dimethylacetamide and completely dissolved. Then, 2g of polyvinyl chloride with a degree of polymerization of 700 and 3.1g of polyethylene glycol 400 were added. After the polyvinyl chloride and polyethylene glycol 400 were completely dissolved, 6g of modified manganese-based lithium ion sieve was added. The mixture was stirred at 50℃ for 1.5h, and then 0.15g of composite catalyst was added. The mixture was stirred for another 30min to obtain premixed slurry A. The composite catalyst was composed of triethylamine and potassium iodide in a mass ratio of 4:1.

[0091] (3) Place the premixed slurry A in a 90℃ constant temperature water bath and stir for 4 hours. Use a syringe to drop the premixed slurry A into 55℃ deionized water to form spheres. Continue to soak the spheres in deionized water for 1.5 hours to solidify and remove solvent and pore-forming agent. Then filter out the spheres, wash them 3 times with deionized water, and put them into a 65℃ forced-air drying oven to dry to constant weight to obtain pre-crosslinked particles B.

[0092] (4) Transfer the pre-crosslinked particles B to a vacuum drying oven and perform deep crosslinking for 2 hours under a vacuum of 1500 Pa and a temperature of 105 °C. Then cool to room temperature to obtain 5# granular manganese lithium ion sieve.

[0093] The No. 5 granular manganese-based lithium ion sieve obtained in this embodiment was scanned to obtain the following results: Figure 7 The SEM image shown. (By...) Figure 7 It can be seen that the surface of the No. 5 granular manganese lithium ion screen is rich in pores and the pores are large. This may be because excessive polyethylene glycol 400 has damaged part of the polyvinyl chloride body.

[0094] Comparative Example 1

[0095] (1) 1g of PEI (number average molecular weight 1800) was added to 30mL of N,N-dimethylacetamide and completely dissolved. Then, 2g of polyvinyl chloride with a degree of polymerization of 700 and 2.4g of polyethylene glycol 400 were added. After the polyvinyl chloride and polyethylene glycol 400 were completely dissolved, 6g of manganese-based lithium ion sieve was added. The mixture was stirred at 50℃ for 1.5h. Then, 0.15g of composite catalyst was added and the mixture was stirred for another 30min to obtain premixed slurry A. The composite catalyst was composed of triethylamine and potassium iodide in a mass ratio of 4:1.

[0096] (2) Place the premixed slurry A in an 85°C constant temperature water bath and stir for 4 hours. Use a syringe to drop the premixed slurry A into 40°C deionized water to form spheres. Continue to soak the spheres in deionized water for 1 hour to solidify and remove solvent and pore-forming agent. Then filter out the spheres, wash them 3 times with deionized water, and dry them in a 70°C forced-air drying oven until constant weight to obtain pre-crosslinked particles B.

[0097] (3) Transfer the pre-crosslinked particles B to a vacuum drying oven and perform deep crosslinking for 1 hour under a vacuum of 1000 Pa and a temperature of 100 °C. Then cool to room temperature to obtain 6# granular manganese lithium ion sieve.

[0098] This comparative example did not use silane coupling agents to modify the surface of the manganese-based lithium ion sieve.

[0099] The No. 6 granular manganese-based lithium ion sieve obtained in this comparative example was scanned, and the results were as follows: Figure 8 The SEM image shown. (By...) Figure 8 It can be seen that the unmodified manganese-based lithium ion sieve powder agglomerates inside the particles and fails to be uniformly dispersed in the cross-linked network and effectively fixed.

[0100] Comparative Example 2

[0101] (1) 10g of manganese-based lithium ion sieve powder was added to 500mL of ethanol-water solution (the volume ratio of anhydrous ethanol to water was 3:1), and ultrasonicated for 30min to disperse the manganese-based lithium ion sieve powder, thereby obtaining a powder solution. Then, 0.35g of KH-560 was added to the powder solution, and the mixture was stirred at 60℃ for 2h to obtain a suspension. In this embodiment, the manganese-based lithium ion sieve powder specifically used was HMn4O5 lithium ion sieve.

[0102] After filtering the suspension, the filter residue was washed three times with anhydrous ethanol, filtered again, and dried at a vacuum of 1000 Pa and a temperature of 80 °C for 5 hours to obtain a modified manganese lithium ion sieve with surface-grafted epoxy groups.

[0103] (2) Add 2g of polyvinyl chloride with a degree of polymerization of 700 and 2.4g of polyethylene glycol 400 to 30mL of N,N-dimethylacetamide and dissolve them completely. Then add 6g of modified manganese lithium ion sieve and stir at 50℃ for 1.5h to obtain premixed slurry A.

[0104] (3) The premixed slurry A was dropped into deionized water at 40°C using a syringe to form spheres. The spheres were soaked in deionized water for 1 hour to solidify and remove solvent and pore-forming agent. The spheres were then filtered out, washed three times with deionized water, and dried in a 70°C forced-air drying oven to constant weight to obtain No. 7 granular manganese lithium ion sieve.

[0105] This comparative example uses a single polyvinyl chloride and does not use polyethyleneimine for cross-linking to granulate manganese-based lithium ion sieve powder.

[0106] The No. 7 granular manganese-based lithium ion sieve obtained in this comparative example was scanned, and the results were as follows: Figure 9 The SEM image shown. (By...) Figure 9 It is known that some of the binder directly covers the surface of the lithium-ion sieve, shielding the adsorption sites and resulting in low adsorption capacity.

[0107] Comparative Example 3

[0108] (1) 10g of manganese-based lithium ion sieve powder was added to 500mL of ethanol-water solution (the volume ratio of anhydrous ethanol to water was 3:1), and ultrasonicated for 30min to disperse the manganese-based lithium ion sieve powder, thereby obtaining a powder solution. Then, 0.35g of KH-560 was added to the powder solution, and the mixture was stirred at 60℃ for 2h to obtain a suspension. In this embodiment, the manganese-based lithium ion sieve powder specifically used was HMn4O5 lithium ion sieve.

[0109] After filtering the suspension, the filter residue was washed three times with anhydrous ethanol, filtered again, and dried at a vacuum of 1000 Pa and a temperature of 80 °C for 5 hours to obtain a modified manganese lithium ion sieve with surface-grafted epoxy groups.

[0110] (2) Add 1g of PEI (number average molecular weight 1800) to 30mL of N,N-dimethylacetamide and dissolve it completely. Then add 2g of polyvinyl chloride with a degree of polymerization of 700 and 2.4g of polyethylene glycol 400. After the polyvinyl chloride and polyethylene glycol 400 are completely dissolved, add 6g of modified manganese lithium ion sieve. Stir at 50℃ for 1.5h, add 0.15g of triethylamine, and continue stirring for 30min to obtain premixed slurry A.

[0111] (3) Place the premixed slurry A in an 85°C constant temperature water bath and stir for 4 hours. Use a syringe to drop the premixed slurry A into 40°C deionized water to form spheres. Continue to soak the spheres in deionized water for 1 hour to solidify and remove solvent and pore-forming agent. Then filter out the spheres, wash them 3 times with deionized water, and dry them in a 70°C forced-air drying oven until constant weight to obtain pre-crosslinked particles B.

[0112] (4) Transfer the pre-crosslinked particles B to a vacuum drying oven and perform deep crosslinking for 1 hour under a vacuum of 1000 Pa and a temperature of 100 °C. Then cool to room temperature to obtain No. 8 granular manganese lithium ion sieve.

[0113] This comparative example uses a single catalyst, triethylamine, and does not use potassium iodide to granulate the manganese-based lithium ion sieve powder.

[0114] The No. 8 granular manganese-based lithium ion sieve obtained in this comparative example was scanned, and the results were as follows: Figure 10 The SEM image shown. (By...) Figure 10 It is evident that the cross-linked network of the No. 8 granular manganese-based lithium ion sieve prepared using only a single catalyst has significant defects.

[0115] Comparative Example 4

[0116] (1) 10g of manganese-based lithium ion sieve powder was added to 500mL of ethanol-water solution (the volume ratio of anhydrous ethanol to water was 3:1), and ultrasonicated for 30min to disperse the manganese-based lithium ion sieve powder, thereby obtaining a powder solution. Then, 0.35g of KH-560 was added to the powder solution, and the mixture was stirred at 60℃ for 2h to obtain a suspension. In this embodiment, the manganese-based lithium ion sieve powder specifically used was HMn4O5 lithium ion sieve.

[0117] After filtering the suspension, the filter residue was washed three times with anhydrous ethanol, filtered again, and dried at a vacuum of 1000 Pa and a temperature of 80 °C for 5 hours to obtain a modified manganese lithium ion sieve with surface-grafted epoxy groups.

[0118] (2) 1g of PEI (number average molecular weight 1800) was added to 30mL of N,N-dimethylacetamide and completely dissolved. Then, 2g of polyvinyl chloride with a degree of polymerization of 700 and 2.4g of polyethylene glycol 400 were added. After the polyvinyl chloride and polyethylene glycol 400 were completely dissolved, 6g of modified manganese-based lithium ion sieve was added. The mixture was stirred at 50℃ for 1.5h, and then 0.15g of composite catalyst was added. The mixture was stirred for another 30min to obtain premixed slurry A. The composite catalyst was composed of triethylamine and potassium iodide in a mass ratio of 6:1.

[0119] (3) Place the premixed slurry A in an 85°C constant temperature water bath and stir for 4 hours. Use a syringe to drop the premixed slurry A into 40°C deionized water to form spheres. Continue to soak the spheres in deionized water for 1 hour to solidify and remove solvent and pore-forming agent. Then filter out the spheres, wash them 3 times with deionized water, and dry them in a 70°C forced-air drying oven until constant weight to obtain pre-crosslinked particles B.

[0120] (4) Transfer the pre-crosslinked particles B to a vacuum drying oven and perform deep crosslinking for 1 hour under a vacuum of 1000 Pa and a temperature of 100 °C. Then cool to room temperature to obtain 9# granular manganese lithium ion sieve.

[0121] This comparative example uses triethylamine and a relatively low amount of potassium iodide to granulate manganese-based lithium ion sieve powder.

[0122] The 9# granular manganese-based lithium ion sieve obtained in this comparative example was scanned, and the results were as follows: Figure 11 The SEM image shown. (By...) Figure 11 It can be seen that the crosslinking degree of the No. 9 granular manganese lithium ion sieve prepared with low potassium iodide is relatively low.

[0123] Comparative Example 5

[0124] (1) 10g of manganese-based lithium ion sieve powder was added to 500mL of ethanol-water solution (the volume ratio of anhydrous ethanol to water was 3:1), and ultrasonicated for 30min to disperse the manganese-based lithium ion sieve powder, thereby obtaining a powder solution. Then, 0.35g of KH-560 was added to the powder solution, and the mixture was stirred at 60℃ for 2h to obtain a suspension. In this embodiment, the manganese-based lithium ion sieve powder specifically used was HMn4O5 lithium ion sieve.

[0125] After filtering the suspension, the filter residue was washed three times with anhydrous ethanol, filtered again, and dried at a vacuum of 1000 Pa and a temperature of 80 °C for 5 hours to obtain a modified manganese lithium ion sieve with surface-grafted epoxy groups.

[0126] (2) 1g of PEI (number average molecular weight 1800) was added to 30mL of N,N-dimethylacetamide and completely dissolved. Then, 2g of polyvinyl chloride with a degree of polymerization of 700 and 2.4g of polyethylene glycol 400 were added. After the polyvinyl chloride and polyethylene glycol 400 were completely dissolved, 6g of modified manganese-based lithium ion sieve was added. The mixture was stirred at 50℃ for 1.5h, and then 0.15g of composite catalyst was added. The mixture was stirred for another 30min to obtain premixed slurry A. The composite catalyst was composed of triethylamine and potassium iodide in a mass ratio of 2:1.

[0127] (3) Place the premixed slurry A in an 85°C constant temperature water bath and stir for 4 hours. Use a syringe to drop the premixed slurry A into 40°C deionized water to form spheres. Continue to soak the spheres in deionized water for 1 hour to solidify and remove solvent and pore-forming agent. Then filter out the spheres, wash them 3 times with deionized water, and dry them in a 70°C forced-air drying oven until constant weight to obtain pre-crosslinked particles B.

[0128] (4) Transfer the pre-crosslinked particles B to a vacuum drying oven and perform deep crosslinking for 1 hour under a vacuum of 1000 Pa and a temperature of 100 °C. Then cool to room temperature to obtain 10# granular manganese lithium ion sieve.

[0129] This comparative example uses triethylamine and excess potassium iodide to granulate manganese-based lithium ion sieve powder.

[0130] The 10# granular manganese-based lithium ion sieve obtained in this comparative example was scanned, and the results were as follows: Figure 12 The SEM image shown. (By...) Figure 12 It can be seen that the No. 10 granular manganese lithium ion sieve prepared by using excessive potassium iodide has excessive cross-linking.

[0131] Comparative Example 6

[0132] (1) 10g of manganese-based lithium ion sieve powder was added to 500mL of ethanol-water solution (the volume ratio of anhydrous ethanol to water was 3:1), and ultrasonicated for 30min to disperse the manganese-based lithium ion sieve powder, thereby obtaining a powder solution. Then, 0.35g of KH-560 was added to the powder solution, and the mixture was stirred at 60℃ for 2h to obtain a suspension. In this embodiment, the manganese-based lithium ion sieve powder specifically used was HMn4O5 lithium ion sieve.

[0133] After filtering the suspension, the filter residue was washed three times with anhydrous ethanol, filtered again, and dried at a vacuum of 1000 Pa and a temperature of 80 °C for 5 hours to obtain a modified manganese lithium ion sieve with surface-grafted epoxy groups.

[0134] (2) 1g of PEI (number average molecular weight 1800) was added to 30mL of N,N-dimethylacetamide and completely dissolved. Then, 2g of polyvinyl chloride with a degree of polymerization of 700 and 2.4g of polyethylene glycol 400 were added. After the polyvinyl chloride and polyethylene glycol 400 were completely dissolved, 6g of modified manganese-based lithium ion sieve was added. The mixture was stirred at 50℃ for 1.5h, and then 0.15g of composite catalyst was added. The mixture was stirred for another 30min to obtain premixed slurry A. The composite catalyst was composed of triethylamine and potassium iodide in a mass ratio of 4:1.

[0135] (3) Using a syringe, premixed slurry A is dropped into deionized water at 40°C to form spheres. The spheres are soaked in deionized water for 1 hour to solidify and remove solvent and pore-forming agent. Then, the spheres are filtered out, washed three times with deionized water, and dried in a 70°C forced-air drying oven to constant weight to obtain particles B.

[0136] (4) Transfer particle B to a vacuum drying oven and perform deep cross-linking for 1 hour under a vacuum of 1000 Pa and a temperature of 100 °C. Then cool to room temperature to obtain 11# granular manganese lithium ion sieve.

[0137] This comparative example did not use pre-crosslinking to granulate the manganese-based lithium ion sieve powder.

[0138] The 11# granular manganese-based lithium ion sieve obtained in this comparative example was scanned, and the results were as follows: Figure 13 The SEM image shown. (By...) Figure 13 It can be seen that the 11# granular manganese-based lithium ion sieve prepared by physical mixing without pre-crosslinking did not form a crosslinked network.

[0139] Comparative Example 7

[0140] This comparative example uses the method described in Example 4 of Patent No. CN119114005A, entitled "A Porous Lithium Metatitanate Type Lithium Ion Screen," to prepare granular manganese-based lithium ion screens.

[0141] (1) 20g of manganese-based lithium ion sieve powder was added to 1L of ethanol aqueous solution (the volume ratio of anhydrous ethanol to water was 3:1), and ultrasonicated for 30min to disperse the manganese-based lithium ion sieve powder to obtain a powder solution. Then, 0.7g of KH-560 was added to the powder solution, and the mixture was stirred at 60℃ for 2h to obtain a suspension. In this embodiment, the manganese-based lithium ion sieve powder specifically used was HMn4O5 lithium ion sieve.

[0142] After filtering the suspension, the filter residue was washed three times with anhydrous ethanol, filtered again, and dried at a vacuum of 1000 Pa and a temperature of 80 °C for 5 hours to obtain a modified manganese lithium ion sieve with surface-grafted epoxy groups.

[0143] (2) Mix 125 ml of gelatin aqueous solution with a mass concentration of 14 g / L, 125 ml of polyvinyl alcohol solution with a mass concentration of 7 g / L and 250 ml of pure aqueous solution evenly to form the aqueous phase.

[0144] (3) Mix 25ml styrene, 25ml divinylbenzene, 75ml toluene and 1.5g initiator benzoyl peroxide evenly as the oil phase.

[0145] (3) Slowly transfer the aqueous phase, oil phase and 20g of modified manganese lithium ion sieve into the separation reactor, keeping the stirring paddle speed at 300rpm.

[0146] (4) After mixing evenly, use a water bath to slowly heat the system to 83°C and keep it stable to enter the suspension granulation stage. Keep the reaction system unchanged for 3 hours. After the suspension granulation stage, slowly continue to heat the system to 95°C, keep the stirring speed unchanged, and enter the particle hardening stage. Keep the reaction system unchanged for 1 hour.

[0147] (5) After the reaction is completed, the lithium ion sieve after sieving and washing is transferred to a Soxhlet extractor containing 200 ml of ethanol solution and extracted at 95 °C for 9 hours to obtain 12# granular manganese lithium ion sieve.

[0148] The 12# granular manganese-based lithium ion sieve obtained in this comparative example was scanned, and the results were as follows: Figure 14 The SEM image shown.

[0149] Adsorption experiments were conducted on the granular manganese-based lithium ion sieves obtained in the above embodiments and comparative examples: the granular manganese-based lithium ion sieves were mixed with 100 mg / L LiOH solution (pH=12) at a solid-liquid ratio of 1 g / L, and stirred for 48 h for adsorption. Li was measured at regular intervals. + Based on the concentration, calculate the adsorption capacity of the granular manganese-based lithium ion sieve. The formula for calculating the adsorption capacity is:

[0150] (1)

[0151] In the formula, Q t The adsorption capacity is expressed as mg / g at a specific time; C0 represents the initial Li in the adsorption solution. + Concentration, in mg / L; C t Li in the adsorbent solution at a specific time + The concentration is expressed in mg / L; V is the volume of the adsorbent solution in L; and m is the mass of the powder in the granular manganese-based lithium ion sieve in mg.

[0152] The various detection data were plotted as adsorption capacity-time curves, as shown below. Figure 15 As shown in Table 1, the equilibrium adsorption capacity of the granular manganese-based lithium ion sieve was obtained based on the adsorption capacity-time curve. Figure 15 In the text, "powder" refers to the original powdered manganese-based lithium ion sieve.

[0153] Depend on Figure 15It can be seen that with the increase of adsorption time, the adsorption capacity of the examples and comparative examples increased rapidly in the first 12 hours, and then gradually tended to reach equilibrium and saturation. However, their adsorption rates were significantly different. After 6 hours of adsorption, the adsorption capacities of Examples 1-5 were 90.95%, 90.09%, 91.02%, 89.96%, and 93.22% of the equilibrium adsorption capacity, respectively. The adsorption capacities of Comparative Examples 1-7 were 80.24%, 44.98%, 84.85%, 84.88%, 88.06%, 76.87%, and 79.05% of the equilibrium adsorption capacity, respectively. The overall adsorption capacity of each example was higher than that of the comparative examples. This indicates that the adsorption kinetics of the granular manganese lithium ion sieve was improved by crosslinking the hydrophilic crosslinking agent with the hydrophobic polymer binder.

[0154] The adsorption liquid after 48 hours of adsorption was filtered to retain the detached powder. After drying, the powder was weighed and the powder loss rate was calculated. The results are shown in Table 1. The formula for calculating the powder loss rate is:

[0155] (2)

[0156] In the formula, L is the powder loss rate of the granular manganese-based lithium ion sieve after 48 hours of adsorption, in units of %; m is the mass of powder retained after 48 hours of adsorption, in units of mg; and M is the total mass of powder in the granular manganese-based lithium ion sieve before adsorption begins, in units of mg.

[0157] Table 1

[0158] Equilibrium adsorption capacity (mg / g) Powder loss rate Example 1 32.69 0.277% Example 2 31.85 0.229% Example 3 33.47 0.372% Example 4 31.64 0.283% Example 5 33.93 0.391% Comparative Example 1 32.19 2.85% Comparative Example 2 19.74 1.037% Comparative Example 3 28.12 1.782% Comparative Example 4 24.21 1.129% Comparative Example 5 29.35 0.95% Comparative Example 6 30.35 8.983% Comparative Example 7 22.34 1.12% Powdered lithium ion sieve 39.57 \

[0159] As shown in Table 1, the preparation method described in this application forms a three-dimensional network structure by adding a hydrophilic crosslinking agent and a hydrophobic polymer binder, which significantly improves the adsorption capacity of granular manganese lithium ion sieves and the effective fixation of powdered lithium ion sieves.

Claims

1. A cross-linking granulation molding method of a particulate manganese-based lithium ion sieve, characterized by, The method comprises the following steps: (1) surface modification of the manganese-based lithium ion sieve powder by silane coupling agent to graft reactive groups on the surface of the manganese-based lithium ion sieve, thereby obtaining modified manganese-based lithium ion sieve; (2) adding a hydrophobic polymer binder, a hydrophilic crosslinking agent, the modified manganese-based lithium ion sieve, a crosslinking aid and a pore-forming agent into a solvent, mixing uniformly to obtain premixed slurry A; (3) placing the premixed slurry A in a constant-temperature water bath for pre-crosslinking to obtain pre-crosslinked slurry, dropping the pre-crosslinked slurry into deionized water to form spheres, continuing to soak the spheres in the deionized water, solidifying and removing the solvent and the pore-forming agent, then washing and drying the spheres to constant weight to obtain pre-crosslinked particles B; (4) deep crosslinking of the pre-crosslinked particles B under vacuum to obtain granular manganese-based lithium ion sieve.

2. The crosslinking pelletizing molding method according to claim 1, wherein, In step (1), the surface modification of the manganese-based lithium ion sieve powder comprises the following steps: First, the manganese-based lithium ion sieve powder is added into an ethanol aqueous solution, stirred and ultrasonically dispersed to obtain a powder solution; Then, the silane coupling agent is added into the powder solution to form a coupling agent mixture, the coupling agent mixture is heated to 50-70 DEG C and kept stirring for 1-3 hours to obtain a suspension; The suspension is filtered, the filter residue is washed with ethanol, and the modified manganese-based lithium ion sieve grafted with epoxy groups on the surface is obtained after drying.

3. The crosslinking pelletizing molding method according to claim 2, characterized by, The ethanol aqueous solution is formed by anhydrous ethanol and water in a volume ratio of (2-4):1, the silane coupling agent is KH-560, and the amount of the silane coupling agent is 2-5% of the mass of the manganese-based lithium ion sieve powder.

4. The crosslinking pelletizing molding method according to claim 1, wherein In step (2), the amount of the solvent is 3-5 times of the total mass of the hydrophobic polymer binder, the hydrophilic crosslinking agent and the modified manganese-based lithium ion sieve, the mass ratio of the hydrophobic polymer binder to the hydrophilic crosslinking agent is 1:(0.2-2), the total mass of the hydrophobic polymer binder and the hydrophilic crosslinking agent to the mass of the modified manganese-based lithium ion sieve is 1:(1-3), the mass of the crosslinking aid is 3-5% of the total mass of the hydrophobic polymer binder and the hydrophilic crosslinking agent, and the mass of the pore-forming agent is 5-8% of the mass of the premixed slurry A.

5. The crosslinking pelletizing molding method according to claim 1, wherein In step (2), the solvent is one or a mixture of two of N,N-dimethylformamide, N,N-dimethylacetamide or tetrahydrofuran; the hydrophobic polymer binder is polyvinyl chloride; the hydrophilic crosslinking agent is polyethyleneimine, and the number average molecular weight of the polyethyleneimine is 600-10000; and the pore-forming agent is polyethylene glycol 400.

6. The crosslinking pelletizing molding method according to claim 1, wherein In step (2), the crosslinking aid is a composite catalyst composed of triethylamine and potassium iodide, and the mass ratio of triethylamine to potassium iodide in the composite catalyst is (3-5):

1.

7. The crosslinking pelletizing molding method according to claim 1, wherein In step (2), the preparation of the premixed slurry A adopts the following steps: first, the hydrophilic crosslinking agent is dissolved in the solvent, after the hydrophilic crosslinking agent is completely dissolved, the hydrophobic polymer binder and the pore-forming agent are added, after the hydrophobic polymer binder and the pore-forming agent are completely dissolved, the modified manganese-based lithium ion sieve is added, stirred uniformly, and finally the crosslinking aid is added and stirred uniformly.

8. The crosslinking pelletizing molding method according to claim 1, wherein In step (3), the pre-crosslinking temperature is 80-90℃, the pre-crosslinking time is 4-6h; the ball is soaked in deionized water for 1-2h, the soaking temperature is 40-60℃; the drying temperature of the ball is 60-80℃.

9. The crosslinking pelletizing molding method according to claim 1, wherein In step (4), during deep crosslinking, the deep crosslinking temperature is 100-120℃, the deep crosslinking time is 1-2h, and the vacuum degree is 800-1500Pa absolute pressure.

10. The granular manganese-based lithium ion sieve prepared by the crosslinking granulation molding method according to any one of claims 1-9.

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