Preparation method of lithium adsorbent with high adsorption efficiency

Abstract

The invention belongs to the field of salt lake lithium extraction adsorbents, and relates to a high-adsorption-efficiency lithium adsorbent preparation method, which comprises: uniformly mixing a granulation base material A, a granulation base material B and a dispersant to obtain a mixed substrate ingredient; the granulation base material A is polyhydric alcohol; the granulation base material B is isocyanate; mixing active powder, the mixed substrate ingredient and a pore-forming agent, and adding the mixture into a rotary mixing granulator for granulation to obtain adsorbent particles; the active powder is an aluminum-based, titanium-based or manganese-based material; screening the adsorbent particles according to a set particle size, and drying and curing the adsorbent meeting the particle size in a drying oven; and filling the cured adsorbent particles into a fixed bed for cyclic activation to obtain the lithium adsorbent. The particle size of the lithium adsorbent is controlled within a very narrow range (0.5-1.2 mm) through a rotary mixing granulation technology, and the mass transfer efficiency in the lithium ion adsorption process is greatly improved.

Description

Technical Field

[0001] The invention belongs to the field of lithium-extracting adsorbents from salt lakes and relates to a method for preparing a lithium adsorbent with high adsorption efficiency. Background Art

[0002] Amidst the global energy transition and the booming new energy industry, lithium, known as the "white oil of the 21st century," has become a core material for power batteries and energy storage technologies. Lithium extraction from salt lakes, due to its vast reserves and environmentally friendly nature, has gradually become a mainstream approach to lithium resource development. However, traditional adsorption technologies face core challenges such as poor adsorption stability, low adsorption efficiency, poor mechanical strength, and significant degradation of lithium extraction performance at low temperatures, severely hindering the large-scale development of lithium resources and improving recovery rates.

[0003] Adsorption, a key technology for lithium extraction from salt lakes, hinges on the design and performance optimization of adsorbents. Research has shown that the adsorption efficiency of the adsorbent directly determines the lithium extraction rate, process energy consumption, and final product purity. While existing adsorbents have achieved industrial application, significant bottlenecks remain. For example, uneven adsorbent particles often lead to biased flow and short-circuiting in the fixed adsorption bed, necessitating optimization through aeration and backwashing, a process that is both complex and energy-intensive. Currently, the majority of commercial lithium adsorbents are granulated using a hydrophobic substrate, resulting in slow adsorption and desorption rates and low mass transfer efficiency. Under certain conditions, such as high pH, high turbidity, and inadequate brine pretreatment, the adsorbent experiences high mechanical loss (e.g., 5%-10% annually). Inadequate compatibility between the adsorbent and brine significantly increases initial investment and production costs. High-altitude salt lake regions experience significant temperature differences between winter and summer, and low-efficiency lithium adsorbents often experience significant performance degradation in winter, leading to significant reductions in lithium carbonate production capacity. Therefore, developing a lithium adsorbent with a narrow particle size distribution, high adsorption efficiency, low loss, and broad adaptability is key to breaking through the bottleneck of lithium extraction technology from salt lakes. This will not only improve the performance of adsorbents for lithium extraction from salt lakes, but also reduce the cost of lithium resource development, enhance the competitiveness of the industrial chain, and promote the green and sustainable development of the new energy industry, providing technical support for the efficient and sustainable development of salt lake lithium resources. Summary of the Invention

[0004] To address these needs, the present invention utilizes an innovative adsorbent manufacturing technology to develop a lithium adsorbent that combines a narrow particle size distribution, high adsorption efficiency, low loss, and broad adaptability. The lithium adsorbent granulation substrate employed in this invention is a polyurethane polymer material formed through a polycondensation reaction of polyols and polyisocyanates, exhibiting excellent mechanical properties and hydrophilicity. This granulation technology is applicable to all currently available mainstream lithium adsorbent active powders.

[0005] The present invention provides a method for preparing a lithium adsorbent with high adsorption efficiency, the steps of which include:

[0006] The granulation base material A, the granulation base material B and the dispersant are mixed evenly to obtain a mixed base ingredient; the granulation base material A is a polyol; the granulation base material B is an isocyanate;

[0007] The active powder, the mixed base ingredients and the pore-forming agent are mixed and added into a rotating mixing granulator for granulation to obtain adsorbent particles; the active powder is aluminum-based, titanium-based or manganese-based material;

[0008] Screening the adsorbent particles according to a set particle size, and placing the adsorbents meeting the particle size in an oven for drying and solidification;

[0009] The solidified adsorbent particles are filled into a fixed bed for cyclic activation to obtain the lithium adsorbent.

[0010] Furthermore, the polyol is one or more of polyether polyol, polyester polyol, polycarbonate polyol, and vegetable oil-based polyol; and the isocyanate is one or more of aromatic isocyanate, aliphatic isocyanate, and alicyclic isocyanate.

[0011] Furthermore, the dispersant is one or more of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAC), N-methylpyrrolidone (NMP), and ethyl acetate (EA).

[0012] Furthermore, the granulation base material A, the granulation base material B and the dispersant are uniformly mixed in a mass ratio of 1:0.8-1.2:0.8-1.

[0013] Furthermore, the pore-forming agent is one of polyvinyl pyrrolidone (PVP K30), polyethylene glycol (PEG), cetyltrimethylammonium bromide (CTAB), polymethyl methacrylate (PMMA), urea, and NaCl.

[0014] Furthermore, the active powder, the mixed base ingredients and the pore-forming agent are uniformly mixed in a mass ratio of 70-85:20-25:0.25-5.

[0015] Furthermore, the rotation speed of the mixing granulator is 2000-3000 r / min, and the time is 10-20 min.

[0016] Furthermore, the particle size is set to be in the range of 0.5 to 1.2 mm.

[0017] Furthermore, after the solidified adsorbent particles are filled into a fixed bed, they are activated by circulating with a 300-500 ppm lithium chloride solution for 1-2 hours.

[0018] The present invention also provides a lithium adsorbent, the particle size of which basically presents a normal distribution trend, with a maximum value interval distributed between 0.9 and 1.0 mm, and is prepared by the above method.

[0019] The beneficial effects of the present invention are as follows:

[0020] The present invention controls the particle size of the lithium adsorbent in a very narrow range (0.5-1.2 mm) through the rotary mixing granulation technology, which greatly improves the mass transfer efficiency during the lithium ion adsorption process. From the perspective of physical structural characteristics, the reduction in the particle size of the lithium adsorbent leads to a significant increase in the specific surface area of the adsorbent per unit mass, exposing more lithium ion adsorption active sites, and increasing the contact area between the lithium adsorbent and the brine fluid, which directly accelerates the surface adsorption reaction rate of lithium ions and also increases the adsorption capacity of the adsorbent. In addition, from the analysis of the mass transfer kinetic mechanism, the smaller the lithium adsorbent particles, the thinner the thickness of the brine liquid film on the surface of the adsorbent particles, and the mass transfer resistance of lithium ions from the brine fluid to the particle surface is reduced. When the adsorbent particle size is reduced, the diffusion distance of the adsorbate from the particle surface to the internal active site (such as micropores and mesopores) is shortened, effectively alleviating the diffusion limitation within the pore (diffusion time is proportional to the square of the distance in Fick's diffusion law). Macroscopically, the lithium adsorbent described in the present invention exhibits an extremely fast lithium adsorption-desorption rate. On the other hand, since the lithium adsorbent granulation substrate used in the present invention is a polyurethane polymer material, the interface has a strong hydrophilicity because it has a large number of hydrophilic groups (such as carboxyl groups, hydroxyl groups, amide groups), etc., and brine can quickly infiltrate the adsorbent body, thereby allowing lithium ions to shuttle more freely between the solid-liquid interface, further realizing the improvement of lithium adsorption efficiency and adsorption capacity.

[0021] The present invention achieves this by a single-step molding process. Due to the combined effects of mechanical rotational shear forces, dispersant, substrate, and other liquid surface tensions, tiny liquid globules are formed. Because the reaction occurs at high temperatures, the bubbles rapidly solidify into small particles. The reactants are placed in a granulator and directly rotated to form the final product. This fast reaction process avoids structural damage to the lithium adsorbent powder, which is thermodynamically unstable and can degrade over extended periods. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a physical picture of the high adsorption efficiency lithium adsorbent of the present invention.

[0023] Figure 2 This is a scanning electron microscope image of the lithium adsorbent with high adsorption efficiency of the present invention.

[0024] Figure 3 This is a particle size distribution diagram of the lithium adsorbent with high adsorption efficiency of the present invention.

[0025] Figure 4 This is a comparison chart of the adsorption efficiency of two groups of titanium-based lithium adsorbents of the present invention.

[0026] Figure 5 This is a long-period test curve of two groups of aluminum-based lithium adsorbents at low temperature (0°C) of the present invention.

[0027] Figure 6 This is a comparison chart of the saturated lithium adsorption capacity of two groups of manganese-based lithium adsorbents of the present invention. DETAILED DESCRIPTION

[0028] The present invention is further described below with reference to the accompanying drawings and examples. In the specific implementation manner, some examples and comparative examples in the experiments of the present invention are disclosed.

[0029] Example 1:

[0030] Granulation base material A, granulation base material B and dispersant are mixed uniformly in a mass ratio of 1.0:1.05:0.87 to obtain a mixed base formulation. Granulation base material A is a mixture of three polyols, mainly polyether polyol, polyester polyol and polycarbonate polyol, with a mass ratio of 1:1.2:1.7; granulation base material B is a mixture of two isocyanates, mainly aromatic isocyanate and aliphatic isocyanate, with a mass ratio of 1:1.4; dispersant is ethyl acetate and N,N-dimethylformamide, with a mass ratio of 1:0.1;

[0031] The active powder, mixed base ingredients, and pore-forming agent were mixed in a mass ratio of 76:23.5:0.5 and added to a rotating mixer granulator for granulation. The granulation process parameters were controlled at a speed of 2400 rpm and a rotation time of 12 minutes. The active powder was an aluminum-based material, and the pore-forming agent was polyvinyl pyrrolidone.

[0032] The adsorbent particles obtained in the above steps are sieved according to the particle size, and samples with a particle size range of 0.5 to 1.2 mm are retained. The byproducts with other particle sizes are crushed and uniformly granulated for secondary reuse;

[0033] The sample with the target particle size range in the above step was placed in an oven at 50°C for 6 hours for drying and solidification;

[0034] The solidified adsorbent was filled into a fixed bed and activated in a 400 ppm lithium chloride solution for 1.5 hours to obtain a final lithium adsorbent product with high adsorption efficiency.

[0035] Example 2:

[0036] Granulation base material A, granulation base material B, and dispersant are mixed uniformly in a mass ratio of 1:0.8:1 to obtain a mixed base formulation, wherein granulation base material A is a polyester polyol, granulation base material B is an alicyclic isocyanate, and dispersant is N,N-dimethylacetamide;

[0037] The active powder, mixed base ingredients, and pore-forming agent were mixed in a mass ratio of 85:20:5 and added to a rotating mixer granulator for granulation. The granulation process parameters were controlled at a speed of 2000 r / min and a rotation time of 20 minutes. The active powder was an aluminum-based material, and the pore-forming agent was NaCl.

[0038] The adsorbent particles obtained in the above steps are sieved according to the particle size, and samples with a particle size range of 0.5 to 1.2 mm are retained. The byproducts with other particle sizes are crushed and uniformly granulated for secondary reuse;

[0039] The sample with the target particle size range in the above step was placed in an oven at 40°C for 8 hours for drying and solidification;

[0040] The solidified adsorbent was filled into a fixed bed and activated in a 500 ppm lithium chloride solution for 1 hour to obtain a final lithium adsorbent product with high adsorption efficiency.

[0041] Example 3:

[0042] Granulation base material A, granulation base material B, and dispersant are mixed uniformly in a mass ratio of 1:1.2:0.8 to obtain a mixed base ingredient. Granulation base material A is a vegetable oil-based polyol, granulation base material B is a mixed isocyanate of two types, aromatic isocyanate and aliphatic isocyanate, with a mass ratio of 1:1; dispersant is a mixture of N-methylpyrrolidone (NMP) and ethyl acetate (EA), with a mass ratio of 1:1;

[0043] The active powder, mixed base ingredients, and pore-forming agent were mixed in a mass ratio of 70:25:0.25 and added to a rotating mixer granulator for granulation. The granulation process parameters were controlled at a speed of 3000 r / min and a rotation time of 10 minutes. The active powder was an aluminum-based material, and the pore-forming agent was polymethyl methacrylate.

[0044] The adsorbent particles obtained in the above steps are sieved according to the particle size, and samples with a particle size range of 0.5 to 1.2 mm are retained. The byproducts with other particle sizes are crushed and uniformly granulated for secondary reuse;

[0045] The sample with the target particle size range in the above step was placed in an oven at 60°C for 4 hours for drying and solidification;

[0046] The solidified adsorbent was filled into a fixed bed and activated in a 300 ppm lithium chloride solution for 2 hours to obtain a final lithium adsorbent product with high adsorption efficiency.

[0047] Example 4:

[0048] Granulation base material A, granulation base material B and dispersant are mixed uniformly in a mass ratio of 1.0:0.9:0.83 to obtain a mixed base formulation. Granulation base material A is a mixture of three polyols, mainly polyether polyol, polyester polyol and polycarbonate polyol, with a mass ratio of 1:1.2:1.7; granulation base material B is a mixture of two isocyanates, mainly aromatic isocyanate and aliphatic isocyanate, with a mass ratio of 1:1.4; dispersant is ethyl acetate and N,N-dimethylformamide, with a mass ratio of 1:0.1;

[0049] The active powder, mixed base ingredients, and pore-forming agent were mixed in a mass ratio of 73:24.5:0.3 and added to a rotating mixer granulator for granulation. The granulation process parameters were controlled at a speed of 2400 rpm and a rotation time of 12 minutes. The active powder was an aluminum-based material, and the pore-forming agent was polyvinyl pyrrolidone.

[0050] The adsorbent particles obtained in the above steps are sieved according to the particle size, and samples with a particle size range of 0.5 to 1.2 mm are retained. The byproducts with other particle sizes are crushed and uniformly granulated for secondary reuse;

[0051] The sample with the target particle size range in the above step was placed in an oven at 50°C for 6 hours for drying and solidification;

[0052] The solidified adsorbent was filled into a fixed bed and activated in a 400 ppm lithium chloride solution for 1.5 hours to obtain a final lithium adsorbent product with high adsorption efficiency.

[0053] Example 5:

[0054] Granulation base material A, granulation base material B and dispersant are mixed uniformly in a mass ratio of 1.0:1.1:0.9 to obtain a mixed base formulation. Granulation base material A is a mixture of three polyols, mainly polyether polyol, polyester polyol and polycarbonate polyol, with a mass ratio of 1:1.2:1.7; granulation base material B is a mixture of two isocyanates, mainly aromatic isocyanate and aliphatic isocyanate, with a mass ratio of 1:1.4; dispersant is ethyl acetate and N,N-dimethylformamide, with a mass ratio of 1:0.1;

[0055] The active powder, mixed base ingredients, and pore-forming agent were mixed in a mass ratio of 80:22:2 and added to a rotating mixer granulator for granulation. The granulation process parameters controlled the rotation speed at 2400 rpm and the rotation time at 12 minutes. The active powder was aluminum-based, and the pore-forming agent was polyvinyl pyrrolidone.

[0056] The adsorbent particles obtained in the above steps are sieved according to the particle size, and samples with a particle size range of 0.5 to 1.2 mm are retained. The byproducts with other particle sizes are crushed and uniformly granulated for secondary reuse;

[0057] The sample with the target particle size range in the above step was placed in an oven at 50°C for 6 hours for drying and solidification;

[0058] The solidified adsorbent was filled into a fixed bed and activated in a 400 ppm lithium chloride solution for 1.5 hours to obtain a final lithium adsorbent product with high adsorption efficiency.

[0059] Comparative Example 1:

[0060] Granulation base material A, granulation base material B, and dispersant were mixed uniformly in a mass ratio of 1.0:1.05:0.87 to obtain a mixed base formulation. Granulation base material A is a mixture of three polyols, mainly polyether polyol, polyester polyol, and polycarbonate polyol, with a mass ratio of 1:1.2:1.7; granulation base material B is a mixture of two isocyanates, mainly aromatic isocyanate and aliphatic isocyanate, with a mass ratio of 1:1.4; and the dispersant is water.

[0061] The active powder, mixed base ingredients, and pore-forming agent were mixed in a mass ratio of 76:23.5:0.5 and added to a rotating mixer granulator for granulation. The granulation process parameters were controlled at a speed of 2400 rpm and a rotation time of 12 minutes. The active powder was an aluminum-based material, and the pore-forming agent was polyvinyl pyrrolidone.

[0062] The adsorbent particles obtained in the above steps are sieved according to the particle size, and samples with a particle size range of 0.5 to 1.2 mm are retained. The byproducts with other particle sizes are crushed and uniformly granulated for secondary reuse;

[0063] The sample with the target particle size range in the above step was placed in an oven at 50°C for 6 hours for drying and solidification;

[0064] The solidified adsorbent was filled into a fixed bed and activated in a 400 ppm lithium chloride solution for 1.5 hours to obtain a final lithium adsorbent product with high adsorption efficiency.

[0065] Comparative Example 2:

[0066] Granulation base material A, granulation base material B, and dispersant are mixed uniformly in a mass ratio of 1:0.8:1 to obtain a mixed base formulation, wherein granulation base material A is a polyester polyol, granulation base material B is an alicyclic isocyanate, and dispersant is N,N-dimethylacetamide;

[0067] The active powder, mixed base ingredients, and pore-forming agent were mixed in a mass ratio of 88:20:5 and added to a rotating mixer granulator for granulation. The granulation process parameters were controlled at a speed of 2000 r / min and a rotation time of 20 minutes. The active powder was an aluminum-based material, and the pore-forming agent was NaCl.

[0068] The adsorbent particles obtained in the above steps are sieved according to the particle size, and samples with a particle size range of 0.5 to 1.2 mm are retained. The byproducts with other particle sizes are crushed and uniformly granulated for secondary reuse;

[0069] The sample with the target particle size range in the above step was placed in an oven at 40°C for 8 hours for drying and solidification;

[0070] The solidified adsorbent was filled into a fixed bed and activated in a 500 ppm lithium chloride solution for 1 hour to obtain a final lithium adsorbent product with high adsorption efficiency.

[0071] Comparative Example 3:

[0072] Granulation base material A, granulation base material B, and dispersant are mixed uniformly in a mass ratio of 1:1.35:0.75 to obtain a mixed base formulation. Granulation base material A is a vegetable oil-based polyol, granulation base material B is a mixed isocyanate of two types, aromatic isocyanate and aliphatic isocyanate, with a mass ratio of 1:1; dispersant is a mixture of N-methylpyrrolidone (NMP) and ethyl acetate (EA), with a mass ratio of 1:1;

[0073] The active powder, mixed base ingredients, and pore-forming agent were mixed in a mass ratio of 70:25:0.25 and added to a rotating mixer granulator for granulation. The granulation process parameters controlled the rotation speed at 3000 r / min and the rotation time at 10 minutes. The active powder was an aluminum-based material, and the pore-forming agent was a mixture of cetyltrimethylammonium bromide (CTAB) and urea, with a mass ratio of 1:1.

[0074] The adsorbent particles obtained in the above steps are sieved according to the particle size, and samples with a particle size range of 0.5 to 1.2 mm are retained. The byproducts with other particle sizes are crushed and uniformly granulated for secondary reuse;

[0075] The sample with the target particle size range in the above step was placed in an oven at 60°C for 4 hours for drying and solidification;

[0076] The solidified adsorbent was filled into a fixed bed and activated in a 300 ppm lithium chloride solution for 2 hours to obtain a final lithium adsorbent product with high adsorption efficiency.

[0077] Comparative Example 4:

[0078] Granulation base material A, granulation base material B and dispersant are mixed uniformly in a mass ratio of 1.0:1.3:1.3 to obtain a mixed base formulation. Granulation base material A is a mixture of three polyols, mainly polyether polyol, polyester polyol and polycarbonate polyol, with a mass ratio of 1:1.2:1.7; granulation base material B is a mixture of two isocyanates, mainly aromatic isocyanate and aliphatic isocyanate, with a mass ratio of 1:1.4; dispersant is ethyl acetate and N,N-dimethylformamide, with a mass ratio of 1:0.1;

[0079] The active powder, mixed base ingredients, and pore-forming agent were mixed in a mass ratio of 76:23.5:0.5 and added to a rotating mixer granulator for granulation. The granulation process parameters were controlled at a speed of 2400 rpm and a rotation time of 12 minutes. The active powder was an aluminum-based material, and the pore-forming agent was polyvinyl pyrrolidone.

[0080] The adsorbent particles obtained in the above steps are sieved according to the particle size, and samples with a particle size range of 0.5 to 1.2 mm are retained. The byproducts with other particle sizes are crushed and uniformly granulated for secondary reuse;

[0081] The sample with the target particle size range in the above step was placed in an oven at 50°C for 6 hours for drying and solidification;

[0082] The solidified adsorbent was filled into a fixed bed and activated in a 400 ppm lithium chloride solution for 1.5 hours to obtain a final lithium adsorbent product with high adsorption efficiency.

[0083] The parameters comparison of the lithium adsorbents prepared in the examples and comparative examples are shown in Table 1.

[0084] Table 1

[0085]

[0086] Please refer to Figure 1 and Figure 2 , Figure 1 and Figure 2 The physical image and scanning electron microscope image of the lithium adsorbent prepared in Example 1 are as follows. Figure 1 and Figure 2 The characterization results show that the lithium adsorbent prepared based on the adsorbent manufacturing technology of the present invention is spherical and has a relatively fine and uniform particle size. Figure 3 The results show that the particle size distribution of the adsorbent basically presents a normal distribution trend. The proportion in the range of 0.5-0.9 mm gradually increases, the proportion in the range of 1.0-1.2 mm gradually decreases, and the maximum value range is distributed between 0.9-1.0 mm (about 18%).

[0087] The present invention further conducted a comparative experiment on the lithium adsorbent prepared in Example 1 and the common lithium adsorbent in the prior art, and the results were as follows: Figure 4 The high adsorption efficiency titanium adsorbent prepared based on Example 1 takes only 20 to 30 minutes from the start of adsorption to the equilibrium adsorption state, while the ordinary titanium lithium adsorbent takes 60 minutes to reach equilibrium under the same conditions. This proves that the high adsorption efficiency titanium adsorbent prepared based on the present invention has obvious advantages in adsorption rate, which is due to the excellent mass transfer efficiency of the adsorbent itself. In addition, the adsorption capacity of the high adsorption efficiency titanium adsorbent is as high as 6.12 g / L, while the adsorption capacity of the ordinary titanium lithium adsorbent is only 5.24 g / L. This is because the interface of the ordinary titanium lithium adsorbent is relatively hydrophobic and the specific surface area is low, resulting in fewer active lithium ion adsorption sites, which is manifested as insufficient adsorption capacity on a macroscopic basis.

[0088] In actual engineering cases, since most salt lake areas are located at high altitudes and the temperature difference between winter and summer is large, the performance of traditional lithium adsorbents often decays significantly at low temperatures. The most critical reason for this is that the diffusion and mass transfer efficiency of lithium ions in the adsorbent bulk phase decreases significantly at low temperatures. The fundamental factor restricting the diffusion and mass transfer efficiency of lithium ions lies in the length of the diffusion path (particle size) and the wetting efficiency of the adsorbent interface (interface hydrophilicity). Figure 5 Further, long-term test curves for the aluminum-based lithium adsorbent prepared using the method of Example 1 and a conventional aluminum-based lithium adsorbent at low temperature (0°C) are presented. The results show that the high-efficiency aluminum-based lithium adsorbent prepared based on the present invention has a significant advantage in lithium extraction efficiency over conventional aluminum-based lithium adsorbents: over 200 test cycles, the average working capacity can reach approximately 2.5 g / L, while the average working capacity of the conventional aluminum-based lithium adsorbent is only approximately 1.7 g / L.

[0089] Figure 6 A comparison of the saturated lithium adsorption capacities of manganese-based lithium adsorbents shows that the manganese-based lithium adsorbent prepared using the method of Example 1 has a saturated capacity of approximately 3.5 g / L, while conventional manganese-based lithium adsorbents have a capacity of only 2.6 g / L. This result further demonstrates the applicability of the innovative adsorbent manufacturing technology described herein to materials with manganese-based active powders. Similar to adsorbents with titanium- and aluminum-based active powders, manganese-based adsorbents offer significant advantages in mass transfer efficiency and adsorption capacity.

Claims

1. A method for preparing a lithium adsorbent with high adsorption efficiency, comprising the steps of: The granulation base material A, the granulation base material B and the dispersant are mixed evenly to obtain a mixed base ingredient; the granulation base material A is a polyol; the granulation base material B is an isocyanate; The active powder, the mixed base ingredients and the pore-forming agent are mixed and added into a rotating mixing granulator for granulation to obtain adsorbent particles; the active powder is aluminum-based, titanium-based or manganese-based material; Screening the adsorbent particles according to a set particle size, and placing the adsorbents meeting the particle size in an oven for drying and solidification; The solidified adsorbent particles are filled into a fixed bed for cyclic activation to obtain the lithium adsorbent.

2. The method according to claim 1, characterized in that The polyol is one or more of polyether polyol, polyester polyol, polycarbonate polyol, and vegetable oil-based polyol; the isocyanate is one or more of aromatic isocyanate, aliphatic isocyanate, and alicyclic isocyanate.

3. The method according to claim 1, characterized in that The dispersant is one or more of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAC), N-methylpyrrolidone (NMP), and ethyl acetate (EA).

4. The method according to claim 1, wherein The granulation base material A, the granulation base material B and the dispersant are uniformly mixed in a mass ratio of 1:0.8-1.2:0.8-1.

5. The method according to claim 1, wherein The pore-forming agent is one of polyvinyl pyrrolidone (PVP K30), polyethylene glycol (PEG), cetyltrimethylammonium bromide (CTAB), polymethyl methacrylate (PMMA), urea, and NaCl.

6. The method according to claim 1, characterized in that The active powder, the mixed base ingredients and the pore-forming agent are uniformly mixed in a mass ratio of 70-85:20-25:0.25-5.

7. The method according to claim 1, characterized in that The rotating speed of the mixing granulator is 2000-3000 r / min, and the time is 10-20 min.

8. The method according to claim 1, characterized in that The particle size is set to be in the range of 0.5 to 1.2 mm.

9. The method according to claim 1, characterized in that After the solidified adsorbent particles are filled into the fixed bed, they are activated by circulating with 300-500 ppm lithium chloride solution for 1-2 hours.

10. A lithium adsorbent, wherein the particle size of the adsorbent substantially presents a normal distribution trend, with a maximum value interval distributed between 0.9 and 1.0 mm, and the adsorbent is prepared by the method according to any one of claims 1 to 9.

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