Spherical lithium ion adsorbent and preparation method and application thereof

Abstract

The invention relates to the technical field of adsorbent preparation, in particular to a spherical lithium ion adsorbent and a preparation method and application thereof. Mixing the resin with an organic solvent to obtain a mixed solution; the resin comprises polysulfone resin, polyacrylonitrile resin, polyvinyl chloride resin, epoxy resin or polyurethane; mixing the mixed solution with a metal adsorbent, and granulating to obtain a spherical lithium ion adsorbent; the metal adsorbent comprises an aluminum adsorbent, a titanium adsorbent or a manganese adsorbent. The spherical lithium ion adsorbent is uniform in particle size and high in roundness, and the dry basis adsorption capacity of the aluminum-series spherical lithium ion adsorbent in a lithium chloride solution with the lithium ion concentration of 1g / L is 11.1 mg / g; the dry basis adsorption capacity of the titanium-series spherical lithium ion adsorbent in a lithium chloride solution with the lithium ion concentration of 1g / L is 64.64 mg / g; the dry basis adsorption capacity of the manganese-series spherical lithium ion adsorbent in a lithium chloride solution with the lithium ion concentration of 1g / L is 18.64 mg / g.

Description

Technical Field

[0001] The present invention relates to the technical field of adsorbent preparation, and particularly to a spherical lithium ion adsorbent, a preparation method thereof and an application thereof. Background Art

[0002] There have been various reports on the shaping of lithium ion adsorption precursors. One type is to in-situ synthesize lithium ion adsorption functional bodies on the surface and inside of porous materials. Patent CN111330548A synthesizes aluminum-based layered double hydroxides on the internal pores of macroporous adsorption resins such as polystyrene, polyacrylonitrile, and polymethyl acrylate. Patent CN108543521A selects to calcine inside ceramic fibers with a loose inner core to prepare lithium manganese composite oxides. Another type is to select a polymer material as an adhesive and mix it with the prepared lithium ion adsorption powder, and use the characteristics of polymer cooling or phase transformation molding to coat the lithium ion adsorption powder to achieve the purpose of molding. Patent CN108722372A mixes an aluminum-based active adsorbent with a hot-melt binder such as polyamide, polypropylene, polyvinyl chloride, etc., and prepares lithium adsorption composite particles through heating, cooling molding, crushing, and screening. Patent CN108479719A embeds lithium ion adsorption powder in a hydrophilic polymer such as hydroxymethyl cellulose, water-soluble starch, etc., and chemically cross-links it after extrusion molding to obtain a high-performance lithium ion adsorbent.

[0003] Spherical adsorbents have good fluidity, high bulk density, high strength, and are convenient to operate, and are widely used in the fields of chemical industry, pharmacy, food, etc. There are also a small number of reports on the preparation method of spherical lithium ion adsorbents. It mainly relies on mixing a solution of a polymer resin with lithium ion adsorption powder to form a homogeneous slurry, and using the characteristics of resin phase transformation molding to drop the slurry into a coagulation bath drop by drop to obtain a uniform spherical adsorbent. Patent CN106076244A blends manganese-based lithium ion adsorption powder, polymer, and organic solvent to obtain a suspension, and the suspension is dropped into water drop by drop to obtain a uniform spherical particle adsorbent. Patent CN103316623A dissolves and mixes chitosan with water or ethanol solvent by heating, adds manganese-based lithium ion sieve powder and stirs evenly to obtain a viscous solution, and then drops the viscous solution into an oil phase composed of petroleum ether or kerosene to obtain a solid spherical adsorbent. Another type uses the method of suspension polymerization for molding. Patent CN116020397A prepares an aqueous phase with a surfactant, a dispersant, and water, prepares an oil phase with styrene monomer, divinylbenzene cross-linking agent, initiator, and pore-forming agent, and then mixes the aqueous phase, oil phase, and adsorbent powder for polymerization to obtain a granular adsorbent.

[0004] There are problems of low adsorption capacity and poor attachment stability of the adsorption functional body in the adsorbent prepared by in-situ synthesis of the lithium-ion adsorption functional body on the surface and inside of the porous material. The low adsorption capacity is mainly due to the limited internal space of the porous material and the limited effective components loaded in a single in-situ synthesis reaction. Multiple loadings are bound to cause problems with the stability of the effective components, and the effective components cannot form stable chemical bonds inside the porous material. Molding the lithium-ion adsorbent powder using the bonding effect of the polymer resin is a most feasible solution, but there are also corresponding problems with different types of polymer resins. The adsorbent prepared with the hot-melt resin binder has problems such as a dense adsorbent structure, limited addition amount of the lithium-ion adsorbent powder, irregular finished particles, and difficult temperature control. The solvent-based polymer resin has good wrapping properties for the powder and also has a large operating space. The process of dropping the mixed slurry into the coagulation bath drop by drop can be used for small-batch production. Due to the great difficulty in uniformly mixing the polymer resin solution and the powder and controlling the mixed slurry, and in addition, the requirements for the molding equipment are high, the industrialization is difficult. The adsorption capacity of the spherical particles prepared by the suspension polymerization process is relatively low, mainly because the mass of the adsorbent powder in the uncured microspheres is limited during the polymerization process. Summary of the Invention

[0005] In order to solve the above problems, the present invention provides a spherical lithium-ion adsorbent, a preparation method thereof, and an application. The spherical lithium-ion adsorbent prepared by the preparation method of the present invention improves the adsorption amount and stability of the adsorbent.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a preparation method of a spherical lithium-ion adsorbent, comprising the following steps:

[0008] 1) Mix the resin with an organic solvent to obtain a mixed solution;

[0009] The mass ratio of the resin to the organic solvent is 12.1 - 18.57:78.125 - 111.43;

[0010] The resin includes polysulfone resin, polyacrylonitrile resin, polyvinyl chloride resin, epoxy resin or polyurethane;

[0011] 2) Mix and granulate the mixed solution obtained in step 1) with a metal-based adsorbent to obtain a spherical lithium-ion adsorbent;

[0012] The mass ratio of the mixed solution to the metal-based adsorbent is 93.75 - 230;

[0013] The metal-based adsorbent includes an aluminum-based adsorbent, a titanium-based adsorbent or a manganese-based adsorbent.

[0014] Preferably, the organic solvent in step 1) includes N,N-dimethylformamide, N,N-dimethylacetamide or acetone.

[0015] Preferably, the temperature of the mixing in step 1) is 50°C.

[0016] Preferably, the particle size of the spherical lithium ion adsorbent in step 2) is 0.5 - 1 mm.

[0017] Preferably, the preparation method of the aluminum-based adsorbent in step 2) includes the following steps:

[0018] 1) Mix aluminum chloride, lithium chloride and water, adjust the pH value to 4.0 - 5.0 to obtain a mixed solution;

[0019] The mass ratio of aluminum chloride, lithium chloride and water is 168:22.6:350;

[0020] Adjust the pH value using a 6 mol / L sodium hydroxide solution;

[0021] The temperature of the mixing is 60°C;

[0022] 2) Stir and age the obtained mixed solution, and successively carry out centrifugation, washing, drying and grinding to obtain the aluminum-based adsorbent;

[0023] The conditions for the stirring and aging include: temperature of 60°C, rotation speed of 150 rpm, and time of 120 min.

[0024] Preferably, the preparation method of the titanium-based adsorbent in step 2) includes the following steps:

[0025] 1) Mix water, absolute ethanol and isopropyl titanate, let stand for 8 h, collect the precipitate and dry to obtain amorphous titanium dioxide;

[0026] The volume ratio of water, absolute ethanol and isopropyl titanate is 1:8:5;

[0027] The temperature of the drying is 80°C;

[0028] 2) Disperse the obtained amorphous titanium dioxide in absolute ethanol, then mix it with lithium carbonate and successively carry out ultrasonic treatment and drying to obtain a dried product;

[0029] The mass ratio of amorphous titanium dioxide and lithium carbonate is 119.8:110.8;

[0030] The time of the ultrasonic treatment is 30 min;

[0031] The temperature of the drying is 60°C;

[0032] 3) Calcinate the obtained dry product at 800 °C for 12 h to obtain the titanium-based adsorbent.

[0033] Preferably, the preparation method of the manganese-based adsorbent in step 2) includes the following steps:

[0034] 1) Mix manganese tetroxide with lithium hydroxide and calcine at 450 °C for 12 h, then let it stand for 15 h to obtain the calcined product;

[0035] 2) Calcinate the obtained calcined product at 720 °C for 10 h to obtain the manganese-based adsorbent.

[0036] The present invention also provides a spherical lithium-ion adsorbent obtained by the preparation method described in the above technical solution.

[0037] The present invention also provides the application of the spherical lithium-ion adsorbent described in the above technical solution in adsorbing lithium ions.

[0038] Preferably, the application includes the following steps:

[0039] 1) Load the spherical lithium-ion adsorbent into an exchange column, and perform water elution to obtain the eluted spherical lithium-ion adsorbent with lithium-ion adsorption capacity;

[0040] The inner diameter of the exchange column is 15 mm, the length is 150 mm, and each exchange column is loaded with 100 mL of spherical lithium-ion adsorbent;

[0041] The conditions for the water elution include: temperature of 40 °C, flow rate of 1 L / h, and time of 1 h;

[0042] 2) Adsorb the lithium-ion-containing solution through the exchange column filled with the eluted spherical lithium-ion adsorbent with lithium-ion adsorption capacity;

[0043] The conditions for the adsorption include: flow rate of 0.5 L / h and time of 6 h.

[0044] The mechanism for the spherical lithium-ion adsorbent provided by the present invention to improve stability and adsorption capacity is as follows:

[0045] Select a polymer as the binder for the powder. This type of binder, combined with an organic solvent with a dilution effect, can effectively reduce the concentration of the polymer to coat more inorganic powders. This is the premise for the high adsorption capacity of the spherical lithium-ion adsorbent. In addition, the presence of the organic solvent also has a certain pore-forming effect. After removing the organic solvent, a large number of microporous structures can be formed inside the adsorbent. The stability of the lithium adsorbent depends on the characteristics of the binder for phase inversion or chemical cross-linking: polysulfone resin, polyacrylonitrile resin, and polyvinyl chloride resin are cured by the resin phase inversion method, and epoxy resin and polyurethane resin are cured by chemical reactions.

[0046] Advantages of the present invention:

[0047] The spherical lithium ion adsorbent prepared by using the preparation method provided by the present invention has uniform particle size and high roundness. The dry basis adsorption capacity of the aluminum-based spherical lithium ion adsorbent in a lithium chloride solution with a lithium ion concentration of 1 g / L is 11.1 mg / g; the dry basis adsorption capacity of the titanium-based spherical lithium ion adsorbent in a lithium chloride solution with a lithium ion concentration of 1 g / L is 22.5 mg / g; the dry basis adsorption capacity of the manganese-based spherical lithium ion adsorbent in a lithium chloride solution with a lithium ion concentration of 1 g / L is 18.64 mg / g. Description of the drawings

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments.

[0049] Figure 1 It is a view of the appearance of the spherical lithium ion adsorbent, where a is the aluminum-based adsorbent, b is the titanium-based adsorbent, and c is the manganese-based adsorbent;

[0050] Figure 2 It is a graph showing the change of the static adsorption amount of the spherical lithium ion adsorbent in a 1 g / L lithium ion solution over time;

[0051] Figure 3 It is a graph of the cycle stability of the spherical lithium ion adsorbent. Detailed implementation manners

[0052] The present invention provides a preparation method of a spherical lithium ion adsorbent, which includes the following steps:

[0053] 1) Mix the resin with an organic solvent to obtain a mixed solution;

[0054] The mass ratio of the resin to the organic solvent is 12.1 - 18.57:78.125 - 111.43;

[0055] The resin includes polysulfone resin, polyacrylonitrile resin, polyvinyl chloride resin, epoxy resin or polyurethane;

[0056] 2) Mix and granulate the mixed solution obtained in step 1) with a metal-based adsorbent to obtain a spherical lithium ion adsorbent;

[0057] The mass ratio of the mixed solution to the metal-based adsorbent is 93.75 - 230;

[0058] The metal-based adsorbent includes an aluminum-based adsorbent, a titanium-based adsorbent or a manganese-based adsorbent.

[0059] The present invention mixes a resin with an organic solvent to obtain a mixed solution; the mass ratio of the resin to the organic solvent is 12.1 - 18.57:78.125 - 111.43; the resin includes polysulfone resin, polyacrylonitrile resin, polyvinyl chloride resin, epoxy resin or polyurethane. The present invention has no special limitation on the source of the resin, and conventional commercially available products can be used. For example, the polysulfone resin is purchased from BASF in Germany, and the product model is 0328; the polyacrylonitrile resin is purchased from BASF in Germany, and the product model is B2035; the polyvinyl chloride resin is purchased from Zhejiang Zhenyang Development Co., Ltd., and the product model is ZY-800; the epoxy resin is purchased from Jiangsu Sanmu Group Co., Ltd., the product model is SM6101, and the curing agent model is 650; the polyurethane is purchased from Hubei Huitian New Materials Co., Ltd., and the product model is 8642. In the present invention, the function of the resin is to bond inorganic powders as an adhesive and granulate through a specific molding device. In the present invention, the organic solvent preferably includes N,N-dimethylformamide, N,N-dimethylacetamide or acetone. In the present invention, the temperature of the mixing is preferably 50°C.

[0060] The present invention mixes the obtained mixed solution with a metal-based adsorbent and granulates to obtain a spherical lithium ion adsorbent; the mass ratio of the mixed solution to the metal-based adsorbent is 93.75 - 230; the metal-based adsorbent includes an aluminum-based adsorbent, a titanium-based adsorbent or a manganese-based adsorbent.

[0061] In the present invention, the particle size of the spherical lithium ion adsorbent is preferably 0.5 - 1 mm. The present invention preferably granulates the mixed solution and the metal-based adsorbent in a granulator to produce particles with a size of 0.5 - 1 mm, and quickly puts them into a rounding machine to improve the roundness of the particles. After screening, curing and drying, a spherical lithium ion adsorbent is obtained. In the present invention, the curing conditions preferably include dynamically washing polysulfone resin, polyacrylonitrile resin and polyvinyl chloride resin with pure water at a flow rate of twice the resin volume per hour for 2 - 4 hours; heating and reacting epoxy resin and polyurethane at 80°C for 4 - 8 hours. In the present invention, the drying conditions preferably include heating at 90°C for 0.5 - 4 h until the water content is 10%.

[0062] In the present invention, the preparation method of the aluminum-based adsorbent preferably includes the following steps:

[0063] 1) Mix aluminum chloride, lithium chloride and water, adjust the pH value to 4.0 - 5.0 to obtain a mixed solution; the mass ratio of aluminum chloride, lithium chloride and water is 168:22.6:350; use a 6 mol / L sodium hydroxide solution to adjust the pH value; the temperature of the reaction during pH adjustment is 60°C;

[0064] 2) Stir and age the obtained mixture, and successively carry out centrifugation, water washing, drying and grinding to obtain an aluminum-based adsorbent; the conditions for the stirring and aging include: the temperature is 60 °C, the rotation speed is 150 rpm, and the time is 120 min.

[0065] In the present invention, the aluminum-based adsorbent is a layered double hydroxide, and its molecular formula is LiCl·2Al(OH)3·nH2O, where 0 ≤ n ≤ 6.

[0066] In the present invention, the preparation method of the titanium-based adsorbent preferably includes the following steps:

[0067] 1) Mix water, anhydrous ethanol and isopropyl titanate, let stand for 8 h, collect the precipitate and dry it to obtain amorphous titanium dioxide; the volume ratio of water, anhydrous ethanol and isopropyl titanate is 1:8:5; the drying temperature is 80 °C;

[0068] 2) Disperse the obtained amorphous titanium dioxide in anhydrous ethanol, then mix it with lithium carbonate and successively carry out ultrasonic treatment and drying to obtain a dried product; the mass ratio of amorphous titanium dioxide to lithium carbonate is 119.8:110.8; the ultrasonic treatment time is 30 min; the drying temperature is 60 °C;

[0069] 3) Calcinate the obtained dried product at 800 °C for 12 h to obtain a titanium-based adsorbent.

[0070] In the present invention, the titanium-based adsorbent has a layered monoclinic crystal structure, and its molecular formula is Li2TiO3.

[0071] In the present invention, the preparation method of the manganese-based adsorbent preferably includes the following steps:

[0072] 1) Mix manganese tetraoxide and lithium hydroxide and calcine at 450 °C for 12 h, let stand for 15 h to obtain a calcined product;

[0073] 2) Calcinate the obtained calcined product at 720 °C for 10 h to obtain a manganese-based adsorbent.

[0074] In the present invention, the manganese-based adsorbent has a spinel structure, and its molecular formula is LiMn2O4, Li 1.33 Mn 1.67 O4 or Li 1.67 Mn 1.67 O4.

[0075] The present invention also provides a spherical lithium-ion adsorbent obtained by the preparation method described in the above technical solution.

[0076] The present invention also provides the application of the spherical lithium-ion adsorbent described in the above technical solution in adsorbing lithium ions.

[0077] In the present invention, the application preferably includes the following steps:

[0078] 1) Pack the spherical lithium ion adsorbent into an exchange column, and perform water elution to obtain an eluted exchange column; the inner diameter of the exchange column is 15 mm, the length is 150 mm, and each exchange column is filled with 100 mL of spherical lithium ion adsorbent; the conditions for the water elution include: temperature of 40 °C, flow rate of 1 L / h, and time of 1 h;

[0079] 2) Pass the lithium ion-containing solution through the eluted exchange column for adsorption; the conditions for the adsorption include: flow rate of 0.5 L / h and time of 6 h.

[0080] To further illustrate the present invention, the present invention will be described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0081] Example 1

[0082] Weigh 168 g of AlCl3·6H20 (0.675 mol) and 22.6 g of anhydrous LiCl (0.506 mol) respectively, dissolve them in 350 mL of distilled water, then keep the temperature constant and mix them evenly by ultrasonic oscillation, dropwise add sodium hydroxide solution with a concentration of 6 mol / L, control the water bath temperature at 60 °C, the feeding time at 30 min, the end point pH value at 5.0, the stirring speed at 150 r / min, and the stirring aging time at 120 min. After the reaction, centrifuge and wash with water for 3 times. Take the precipitate, dry it and then grind it to obtain an aluminum-based adsorbent powder with the molecular formula LiCl·2Al(OH)3·H2O.

[0083] Accurately weigh 18.57 g of polyvinyl chloride resin and add it to 111.43 g of acetone organic solvent. Heat and stir at 50 °C until the polymer is completely dissolved. Mix the dissolved polyvinyl chloride resin solution with 300 g of aluminum-based adsorbent powder evenly. Put the mixed material into a granulator to make particles with a particle size of 0.5 - 1.0 mm, and quickly put them into a rounding machine to improve the roundness of the particles. The rounded particles are screened, and the particles are loaded into an exchange column and dynamically washed with pure water at a flow rate of twice the resin volume per hour for 2 hours for curing, and then dried in a fluidized bed dryer at 80 °C for 1 hour to obtain an aluminum-based spherical lithium ion adsorbent with a particle size of 0.5 - 1.0 mm.

[0084] Add 1 g of the above-mentioned aluminum-based spherical lithium ion adsorbent to 50 mL of pure water, put it into a constant temperature shaker at 40 °C and wash for 1 h. Add the washed adsorbent to 50 mL of lithium chloride solution with a lithium ion concentration of 1 g / L, and adsorb at room temperature (25 °C) for 4 h. The remaining lithium ion concentration in the solution is 778 mg / L. Calculate the adsorption capacity of the aluminum-based spherical lithium ion adsorbent to be 11.1 mg / g.

[0085] Example 2

[0086] Mix 100 mL of deionized water and 800 mL of absolute ethanol and stir continuously. Then, dropwise add 500 mL of isopropyl titanate to the above solution until complete hydrolysis. After that, let the white suspension stand for 8 h, collect the precipitate, wash it with absolute ethanol, and then dry it at 80 °C to obtain amorphous TiO₂. Disperse 119.8 g of the prepared amorphous TiO₂ powder in absolute ethanol, then add 110.8 g of Li₂CO₃ powder and stir continuously. Thereafter, ultrasonically treat the mixture for 30 min, then dry it at 60 °C. Heat the obtained powder in a muffle furnace from room temperature to 800 °C at a heating rate of 5 °C / min, then hold for 12 h, and obtain titanium-based adsorbent powder, Li₂TiO₃, after grinding.

[0087] Accurately weigh 12.10 g of polyacrylonitrile resin and add it to 84.7 g of N,N-dimethylacetamide organic solvent. Heat and stir at 50 °C until the polymer is completely dissolved. Uniformly mix the dissolved polyvinyl chloride resin solution with 300 g of titanium-based adsorbent powder. Feed the mixed material into a granulator to produce particles with a particle size of 0.5 - 1.0 mm and quickly put them into a rounding machine to improve the roundness of the particles. Screen the rounded particles, load the particles into an exchange column, and dynamically wash them with pure water at a flow rate of twice the resin volume per hour for 3 h for curing, and then dry them in a fluidized bed dryer at 80 °C for 30 min to obtain titanium-based spherical lithium ion adsorbents with a particle size of 0.5 - 1.0 mm.

[0088] Add 1 g of the above titanium-based spherical lithium ion adsorbent to 50 mL of 0.2 mol / L hydrochloric acid solution, place it in a constant temperature shaking incubator at 60 °C for cleaning for 4 h. Add the washed adsorbent to 50 mL of lithium chloride solution with a lithium ion concentration of 1 g / L, adsorb at 50 °C for 24 h, and the remaining lithium ion concentration in the solution is 550 mg / L. Calculate the adsorption capacity of the titanium-based spherical lithium ion adsorbent to be 34.64 mg / g.

[0089] Example 3

[0090] Weigh 376 g of MnO₂ and calcine it in a box-type resistance furnace at 1100 °C for 4 h to obtain the product Mn₃O₄. Grind 61.016 g of Mn₃O₄ and 16.784 g of LiOH·H₂O evenly in an agate mortar, then heat from room temperature to 450 °C at a heating rate of 10 °C / min and calcine in a muffle furnace for 12 h. After standing for 15 h, grind the calcined product evenly in an agate mortar again and place it in a muffle furnace at 720 °C for calcining for 10 h. Finally, obtain manganese-based adsorbent powder, LiMn₂O₄, after grinding.

[0091] Accurately weigh 15.625 g of epoxy resin and add it to 78.125 g of N,N-dimethylformamide organic solvent. Heat and stir at 50 °C until the polymer is completely dissolved. Uniformly mix the dissolved epoxy resin solution with 300 g of manganese-based adsorbent powder. Feed the mixed material into a granulator to produce particles with a particle size of 0.5 - 1.0 mm and quickly put them into a rounding machine to improve the roundness of the particles. The rounded particles are screened, and the particles are cured in a fluidized bed dryer at 80 °C for 1 hour to obtain manganese-based spherical lithium ion adsorbents with a particle size of 0.5 - 1.0 mm.

[0092] Add 1 g of the above-mentioned manganese-based spherical lithium ion adsorbent to 50 mL of 0.5 mol / L hydrochloric acid solution, place it in a constant temperature shaking oscillator at room temperature for 2 h for cleaning. Add the washed adsorbent to 50 mL of lithium chloride solution with a lithium ion concentration of 1 g / L, and adsorb at 25 °C for 10 h. The remaining lithium ion concentration in the solution is 627.2 mg / L. Calculate the adsorption capacity of the manganese-based spherical lithium ion adsorbent to be 18.64 mg / g.

[0093] Example 4

[0094] Use simulated salt lake brine to test the adsorption performance of the spherical lithium ion adsorbents prepared in Examples 1, 2, and 3.

[0095] The simulated salt lake brine is prepared using MgCl2·6H2O, LiCl, CaCl2, KCl, and NaCl as raw materials respectively, and the composition of metal cations is shown in Table 1.

[0096] Table 1 Chemical composition of metal cations in simulated brine

[0097] Element <![CDATA[Li + > <![CDATA[Mg 2+ > <![CDATA[Ca 2+ > <![CDATA[Na + > <![CDATA[K + > Content (ppm) 383 22100 41 590 210

[0098] Accurately measure 100 mL of the aluminum-based spherical lithium ion adsorbent prepared in Example 1 and place it in a jacketed exchange column with an inner diameter of 15 mm and a length of 150 mm. Use pure water at 40 °C as the eluent to elute the adsorbent, with an elution flow rate of 1 L / h and a running time of 1 h. After elution, introduce the simulated brine solution at room temperature for adsorption, with an adsorption flow rate of 0.5 L / h and a running time of 6 h. Take samples of every 0.6 L of the effluent to detect the ion content in the solution. After adsorption, use pure water at 40 °C for elution, with an elution flow rate of 1 L / h and a running time of 1 h. Take samples of every 0.2 L of the effluent to detect the ion content in the solution. Take one adsorption-elution cycle and continuously run 20 cycles to test the cycle stability of the adsorbent.

[0099] The results of this experiment are as Figure 3 shown, from Figure 3It can be seen that the spherical aluminum-based lithium ion adsorbent prepared in Example 1 has a relatively stable adsorption capacity within 300 consecutive operation cycles, and the decline rate of the adsorption capacity is less than 10%.

[0100] Although the above embodiments have made a detailed description of the present invention, they are only a part of the embodiments of the present invention, rather than all embodiments. People can also obtain other embodiments based on these embodiments without creative efforts, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A preparation method of a spherical lithium ion adsorbent, characterized in that, It includes the following steps: 1) Mix the resin with an organic solvent to obtain a mixed solution; The mass ratio of the resin to the organic solvent is 12.1 - 18.57:78.125 - 111.43; The resin includes polysulfone resin, polyacrylonitrile resin, polyvinyl chloride resin, epoxy resin or polyurethane; 2) Mix and granulate the mixed solution obtained in step 1) with a metal-based adsorbent to obtain a spherical lithium ion adsorbent; The mass ratio of the mixed solution to the metal-based adsorbent is 93.75 - 230; The metal-based adsorbent includes an aluminum-based adsorbent, a titanium-based adsorbent or a manganese-based adsorbent.

2. The preparation method according to claim 1, wherein The organic solvent in step 1) includes N,N-dimethylformamide, N,N-dimethylacetamide or acetone.

3. The preparation method according to claim 1, characterized in that, The temperature of mixing in step 1) is 50 °C.

4. The preparation method according to claim 1, characterized in that, The particle size of the spherical lithium ion adsorbent in step 2) is 0.5 - 1 mm.

5. The preparation method according to claim 1, characterized in that, The preparation method of the aluminum-based adsorbent in step 2) includes the following steps: 1) Mix aluminum chloride, lithium chloride and water, adjust the pH value to 4.0 - 5.0 to obtain a mixed solution; The mass ratio of aluminum chloride, lithium chloride and water is 168:22.6:350; Use a 6 mol / L sodium hydroxide solution to adjust the pH value; The temperature of mixing is 60 °C; 2) Stir and age the obtained mixed solution, and successively carry out centrifugation, water washing, drying and grinding to obtain an aluminum-based adsorbent; The conditions for stirring and aging include: temperature is 60 °C, rotation speed is 150 rpm, and time is 120 min.

6. The preparation method according to claim 1, characterized in that, The preparation method of the titanium-based adsorbent in step 2) includes the following steps: 1) Mix water, anhydrous ethanol and isopropyl titanate, let it stand for 8 h, collect the precipitate and dry it to obtain amorphous titanium dioxide; The volume ratio of water, anhydrous ethanol and isopropyl titanate is 1:8:5; The temperature of drying is 80 °C; 2) Disperse the obtained amorphous titanium dioxide in anhydrous ethanol, then mix it with lithium carbonate and successively carry out ultrasonic treatment and drying to obtain a dried product; The mass ratio of amorphous titanium dioxide to lithium carbonate is 119.8:110.8; The time of ultrasonic treatment is 30 min; The temperature of drying is 60 °C; 3) Calcinate the obtained dried product at 800 °C for 12 h to obtain a titanium-based adsorbent.

7. The preparation method according to claim 1, characterized in that, The preparation method of the manganese-based adsorbent in step 2) includes the following steps: 1) Mix manganese tetroxide with lithium hydroxide and calcine at 450 °C for 12 h, let it stand for 15 h to obtain a calcined product; 2) Calcinate the obtained calcined product at 720 °C for 10 h to obtain a manganese-based adsorbent.

8. A spherical lithium ion adsorbent obtained by the preparation method according to any one of claims 1 - 7.

9. Application of the spherical lithium ion adsorbent according to claim 8 in adsorbing lithium ions.

10. The application according to claim 9, wherein The application includes the following steps: 1) Load the spherical lithium ion adsorbent into an exchange column, and carry out water elution to obtain an eluted spherical lithium ion adsorbent with lithium ion adsorption capacity; The inner diameter of the exchange column is 15 mm, the length is 150 mm, and each exchange column is loaded with 100 mL of spherical lithium ion adsorbent; The conditions for the water elution include: temperature of 40 °C, flow rate of 1 L / h, and time of 1 h; 2) Adsorb the lithium-ion-containing solution through an exchange column filled with spherical lithium-ion adsorbents with lithium-ion adsorption capacity after the elution; The conditions for the adsorption include: flow rate of 0.5 L / h and time of 6 h. The lithium-ion adsorbent after adsorption is eluted again according to the above elution conditions, and the adsorption-elution process is regarded as one complete cycle.

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