Lithium adsorbent particles, and methods of making and using the same

Abstract

The application discloses a lithium adsorbent particle and a preparation method and application thereof, and the lithium adsorbent particle contains a lithium adsorbent precursor powder, a polypeptide, a high-molecular binder and a pore-forming agent in the inside. The polypeptide crosslinks the precursor powder, the high-molecular binder and the pore-forming agent into a network structure through chain entanglement and hydrogen bond interaction between the polypeptide, the high-molecular binder and the pore-forming agent and self-crosslinking. The application aims to solve the problems in the existing forming and granulating technology, such as large amount of binder, low proportion of effective component lithium adsorbent precursor, low hydrophilicity of the surface of the adsorbent particle, low adsorption capacity after granulation, low lithium extraction efficiency and the like.

Description

Technical Field

[0001] This invention belongs to the field of lithium extraction technology from salt lakes, specifically relating to a lithium adsorbent particle, its preparation method, and its application. Background Technology

[0002] As the cumulative number of retired power batteries in my country continues to rise, battery recycling is poised for rapid development. Overall, whether it's lithium extraction from salt lakes or battery recycling, high-performance lithium extraction materials and green, efficient, and low-cost combined processes will be key to the industry's growth.

[0003] As a core material in the field of lithium extraction technology, adsorbents typically need to possess the following three characteristics: 1) Excellent selective adsorption: They should be able to selectively adsorb lithium ions from the solution while allowing other ions to pass through; 2) Good stability: They should maintain good performance, structure, and mechanical stability in high-salinity environments and during repeated adsorption and desorption processes; 3) High adsorption capacity: A unit mass of adsorbent material should be able to adsorb as many lithium ions as possible.

[0004] In the prior art, CN109225124A discloses a method for preparing granular lithium adsorbents. The method involves mixing and stirring lithium adsorbent or its precursor powder, various polymers, a pore-forming agent, and an organic solvent under a certain pressure and temperature to obtain a homogeneous mixture. This homogeneous mixture is then dropped into a solution or extruded and crushed, followed by washing to obtain granular lithium adsorbents. The adsorbent particles prepared by this invention have high strength and good toughness, making them suitable for industrial applications. However, this method does not consider the low bonding strength between the adsorbent powder and the polymer and the problem of powder loss. CN115845825B discloses a method for preparing lithium adsorbents, involving mixing a binder, a pore-forming agent, and precursor powder in a solvent in a specific ratio, followed by spin-curing and granulation to achieve the granulation of powdered lithium adsorbents. This invention utilizes water-soluble organic compounds of varying molecular weights as porogens, ultimately confirming the formation of a unique gradient pore structure within the product. This gradient pore structure helps prevent powder loss and ion transfer, effectively improving the adsorbent's lifespan and promoting faster adsorption and desorption rates. However, this method still suffers from drawbacks, including the large amount of polymer binder required and weak adhesion between the binder and the powder, leading to reduced cycle life due to adsorbent wear over long-term use. Furthermore, the loss of hydrophilic porogens in the coagulation bath results in low hydrophilicity on the adsorbent particle surface, hindering further improvements in adsorption capacity and lithium extraction rate.

[0005] Therefore, it is necessary to improve the bonding strength between the binder and the powder and the hydrophilicity of the adsorbent surface to solve the problems of large amount of polymer binder and low hydrophilicity of adsorbent particle surface in the existing technology. Summary of the Invention

[0006] This invention aims to solve the problems in existing molding and granulation technologies, such as large amount of binder, low proportion of effective lithium adsorbent precursor, low hydrophilicity of adsorbent particle surface, low adsorption capacity after granulation, and low lithium extraction efficiency. It provides a lithium adsorbent particle, its preparation method, and its application.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides lithium adsorbent particles containing lithium adsorbent precursor powder, polypeptides, polymeric binders, and porogens. The polypeptides, through chain entanglement and hydrogen bonding interactions with the polymeric binders and porogens, as well as self-crosslinking, crosslink the precursor powder, polymeric binders, and porogens into a network structure, thereby enhancing the overall viscosity and surface hydrophilicity of the adsorbent particles.

[0009] Furthermore, the polypeptide is formed by the dehydration condensation of 2 to 10 amino acids and has a molecular weight of 200 to 1500.

[0010] Furthermore, the mass ratio of the polypeptide to the polymeric binder is 0.1 to 1:1, preferably 0.1 to 0.5:1.

[0011] Furthermore, the mass ratio of the lithium adsorbent precursor powder to the polymer binder is 5 to 50:1, preferably 5 to 20:1.

[0012] Furthermore, the lithium adsorbent precursor powder is selected from LiCl·2Al(OH)3·nH2O, LiMn2O4, and Li 1.6 Mn 1.6 O4, Li 1.33 Mn 1.67 O4, Li2TiO3, Li4Ti5O 12 One or more of them.

[0013] Furthermore, the lithium adsorbent precursor powder has a particle size of 0.1-100 μm, preferably 1-50 μm.

[0014] Furthermore, the polymeric binder is selected from one or more of polysulfone, polyvinylidene fluoride, polyvinyl chloride, chlorinated polyvinyl chloride, cellulose acetate, carboxymethyl cellulose, and chitosan.

[0015] Furthermore, the pore-forming agent is selected from one or a mixture of several of PVP K30, PVP K60, PVP K90, PEG-1000, PEG-2000, and PEG-6000.

[0016] Furthermore, the amount of the pore-forming agent is 0.1-5 wt% of the mass of the lithium adsorbent precursor powder.

[0017] In a second aspect, the present invention provides a method for preparing lithium adsorbent particles, comprising the following steps:

[0018] (1) The lithium adsorbent precursor powder, polypeptide, polymer binder, organic solvent and pore-forming agent are mixed evenly at high temperature to obtain a mixture.

[0019] (2) The mixture is solidified, dried, crushed and sieved to obtain a lithium adsorbent semi-finished product;

[0020] (3) The lithium adsorbent semi-finished product is post-treated with deionized water to obtain lithium adsorbent particles.

[0021] Further, in step (1), the organic solvent is selected from one or a mixture of several of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, chloroform, dichloroethane, and ethyl acetate. Preferably, the amount of organic solvent used is 50 to 100% of the total mass of the precursor powder, polypeptide, and polymer binder.

[0022] Furthermore, in step (1), the mixing temperature is 80-120°C and the mixing time is 1-5 hours.

[0023] Furthermore, in step (2), the particle size of the lithium adsorbent semi-finished product obtained by crushing and sieving is 0.5 mm to 3.0 mm.

[0024] Further, in step (3), the deionized water post-treatment temperature is 25-45℃, and the lithium adsorbent semi-finished product is treated with a stirring rate of 20-120r / min for 12-48h. After filtering to remove excess water, lithium adsorbent particles are obtained.

[0025] Thirdly, the present invention provides the application of the lithium adsorbent prepared by the above-mentioned method in the field of lithium extraction technology from salt lakes.

[0026] The beneficial effects of this invention are as follows: This invention provides lithium adsorbent particles containing lithium adsorbent precursor powder, polypeptides, polymeric binders, and porogens. The polypeptides, through chain entanglement and hydrogen bonding interactions with the polymeric binders and porogens, as well as self-crosslinking, crosslink the precursor powder, polymeric binders, and porogens into a network structure, enhancing the overall viscosity and surface hydrophilicity of the adsorbent particles. This is because polypeptides are formed by the dehydration condensation of multiple amino acid molecules and can act as hydrogen donors, forming hydrogen bonds with molecules containing hydrogen acceptors. Furthermore, the residual carboxyl and amino groups of the polypeptides, under suitable excitation conditions, can undergo self-crosslinking to form peptide bonds, providing stable and reversible crosslinking points between polymers, thereby achieving polymer crosslinking and self-assembly.

[0027] In the preparation process of this invention, the adsorbent precursor powder, peptide, polymeric binder, and pore-forming agent are uniformly mixed together. During mixing, the peptide cross-links with the polymeric binder and pore-forming agent through chain entanglement and hydrogen bonding to form a network structure. During post-treatment with deionized water: on the one hand, the pore-forming agent in the adsorbent particles dissolves and diffuses into the deionized water, thereby forming a porous structure on the particle surface and inside. Due to the chain entanglement and hydrogen bonding between the peptide and the hydrophilic pore-forming agent, more hydrophilic pore-forming agent is anchored to the porous structure surface, significantly increasing the hydrophilicity of the adsorbent particle surface. On the other hand, under suitable water treatment temperature conditions, the residual carboxyl and amino groups of the peptide self-crosslink to form peptide bonds, providing stable and reversible crosslinking points between polymers, further enhancing the adhesion between the precursor powder and the polymeric binder. This overall cross-linked network structure reduces the amount of binder used and increases the proportion of lithium adsorbent precursor powder, thereby significantly increasing the effective component ratio of the formed lithium adsorbent particles. Furthermore, the polypeptides used in this invention improve the hydrophilicity of the lithium adsorbent, making the interaction between the adsorbent and the brine stronger, which is beneficial to improving the lithium extraction rate. It also makes the lithium adsorbent precursor powder bond more firmly, which is beneficial to improving the wear resistance and cycle life of the adsorbent. Detailed Implementation

[0028] To facilitate understanding of the present invention, the following description, in conjunction with embodiments, will further illustrate the invention. It should be understood that the following embodiments are merely for a better understanding of the invention and do not imply that the invention is limited to these embodiments.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The term "and / or" may be used herein to include any and all combinations of one or more of the associated listed items.

[0030] The main sources used in the embodiments and comparative examples of this invention are as follows. Unless otherwise specified, other raw materials and reagents can be obtained from commercially available sources:

[0031] The lithium adsorbent precursor LiCl.2Al(OH)3.H2O was prepared using the method disclosed in the reference "Aluminium hydroxide as selective sorbent of lithium salts from brines and technical solutions".

[0032] Li 1.6 Mn 1.6 O4 was prepared using the method disclosed in the reference "Preparation of High Manganese-to-Lith Ratio Adsorbent Materials and Study on Lithium Adsorption Performance";

[0033] Li2TiO3, tripeptide (copper peptide), and decapeptide-4 were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0034] The performance testing methods in various embodiments of the present invention are as follows:

[0035] Adsorption capacity detection method: Approximately 50g (dry weight) of adsorbent particles were loaded into a glass chromatography column and adsorbed using a salt lake brine with a high magnesium-to-lithium ratio (magnesium content 4g / kg, lithium content 0.2g / kg) for 1 hour. Then, the adsorption was desorbed with deionized water at room temperature for 1 hour. The adsorption capacity and desorption capacity were calculated based on the lithium ion concentration difference in the water sample.

[0036] Cycle life evaluation method: According to the adsorption and desorption process in the adsorption capacity test method, simulate 1000 cycles of continuous dynamic operation in industrial settings, and calculate the dissolution loss based on the mass difference of the adsorbent.

[0037] Example 1

[0038] Weigh 100g of lithium adsorbent precursor powder LiCl·2Al(OH)3·H2O (particle size 50–100 μm), 20g of polyvinylidene fluoride, 2g of tripeptide, 3g of PVP K90, and 100g of N,N-dimethylformamide. Mix them in a kneader at 80°C for 5 hours to obtain a mixture. Then, remove the solvent using an atmospheric pressure drying oven. Crush the mixture and sieve out particles with a diameter of 0.5–3 mm. Stir the mixture with deionized water at 120 r / min at 25°C for 48 hours. Filter out excess water to obtain granular lithium adsorbent.

[0039] Example 2

[0040] Weigh 100g of lithium adsorbent precursor powder LiCl.2Al(OH)3.H2O (particle size 1-20μm), 5g of polysulfone, 2.5g of decapeptide-4, 0.5g of PEG-2000, and 60g of N,N-dimethylacetamide. Mix them in a kneader at 100℃ for 2 hours to obtain a mixture. Then, remove the solvent using an atmospheric pressure drying oven. Crush the mixture and sieve out particles with a diameter of 0.5-3mm. Stir the mixture with deionized water at 20r / min at 45℃ for 12 hours. Filter out excess water to obtain granular lithium adsorbent.

[0041] Example 3

[0042] Weigh 100g of lithium adsorbent precursor powder LiCl·2Al(OH)3·H2O (particle size 20–50 μm), 20g of polyvinylidene fluoride, 2.5g of tripeptide, 0.5g of PEG-6000, and 120g of N,N-dimethylformamide. Mix them in a kneader at 120℃ for 1.5h to obtain a mixture. Then, remove the solvent using an atmospheric pressure drying oven. Crush the mixture and sieve out particles with a diameter of 0.5–3 mm. Stir with deionized water at 70 r / min at 35℃ for 24h. Filter out excess water to obtain granular lithium adsorbent.

[0043] Example 4

[0044] Weigh 100g of lithium adsorbent precursor powder Li 1.6 Mn 1.6 O4 (particle size 20–50 μm), 20 g polyvinylidene fluoride (PVDF), 2.5 g decapeptide-4, 0.5 g PVP K30, and 80 g N-methylpyrrolidone were mixed in a kneader at 120 °C for 1.5 h to obtain a mixture. The solvent was then removed using an atmospheric pressure drying oven. The mixture was pulverized, and particles with a diameter of 0.5–3 mm were sieved out. The mixture was then stirred with deionized water at 70 r / min at 35 °C for 24 h. Excess water was filtered off to obtain granular lithium adsorbent.

[0045] Example 5

[0046] Weigh 100g of lithium adsorbent precursor powder Li₂TiO₃ (particle size 20–50 μm), 20g of polyvinylidene fluoride, 2.5g of decapeptide-4, 0.5g of PEG-6000, and 120g of N,N-dimethylformamide. Mix them in a kneader at 120°C for 1.5 h to obtain a mixture. Then, remove the solvent using an atmospheric pressure drying oven. Crush the mixture and sieve out particles with a diameter of 0.5–3 mm. Stir the mixture with deionized water at 70 r / min at 35°C for 24 h. Filter out excess water to obtain granular lithium adsorbent.

[0047] Comparative Example 1

[0048] Weigh 100g of lithium adsorbent precursor powder LiCl.2Al(OH)3.H2O (particle size 20-50μm), 20g of polyvinylidene fluoride, 0.5g of PEG-6000, and 120g of N,N-dimethylformamide. Mix them in a kneader at 120℃ for 1.5h to obtain a mixture. This mixture cannot be formed into a single mass, and many lithium adsorbent precursor powder particles remain unbonded. Remove the solvent from the mixture using an atmospheric pressure drying oven, pulverize it, and sieve out particles with a diameter of 0.5-3mm. Stir the mixture with deionized water at 70r / min at 35℃ for 24h, and filter out excess water to obtain granular lithium adsorbent.

[0049] Comparative Example 2

[0050] Weigh 100g of lithium adsorbent precursor powder Li₂TiO₃ (particle size 20–50 μm), 20g of polyvinylidene fluoride (PVDF), 0.5g of PEG-6000, and 120g of N,N-dimethylformamide. Mix them in a kneader at 120°C for 1.5 hours to obtain a mixture. This mixture cannot be formed into a single mass, and many lithium adsorbent precursor powder particles remain unbonded. Remove the solvent from the mixture using an atmospheric pressure drying oven, pulverize it, and sieve out particles with a diameter of 0.5–3 mm. Stir the mixture with deionized water at 70 rpm for 24 hours at 35°C, and filter out excess water to obtain granular lithium adsorbent.

[0051] The adsorption and desorption capacity test results of the samples in Examples 1-5 and Comparative Examples 1-2 are as follows:

[0052] Lithium adsorption capacity (mg / g) Lithium extraction capacity (mg / g) Example 1 10.6 10.5 Example 2 9.2 9.2 Example 3 12.9 12.9 Example 4 11.8 11.8 Example 5 10.5 10.5 Comparative Example 1 7.4 7.4 Comparative Example 2 6.9 6.8

[0053] The cycle life test results using the sample from Example 3 are as follows:

[0054]

[0055]

[0056] As can be seen from the table, the prepared granular lithium adsorbent has strong cycle stability, low solubility, good wear resistance and cycle life.

[0057] It is readily understood that the above embodiments are merely illustrative examples for clear explanation and do not imply that the invention is limited thereto. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A lithium adsorbent particle, characterized in that, The raw material contains lithium adsorbent precursor powder, polypeptide, polymer binder and pore-forming agent; the polypeptide is formed by the dehydration condensation of 2 to 10 amino acids, with a molecular weight of 200 to 1500, and the mass ratio of the polypeptide to the polymer binder is 0.1 to 1:

1. The polymeric binder is selected from one or more of polysulfone, polyvinylidene fluoride, polyvinyl chloride, chlorinated polyvinyl chloride, cellulose acetate, carboxymethyl cellulose, and chitosan; the porogen is selected from one or more of PVPK30, PVPK60, PVPK90, PEG-1000, PEG-2000, and PEG-6000.

2. The lithium adsorbent particles according to claim 1, characterized in that, The lithium adsorbent precursor powder is selected from LiCl.2Al(OH)3.nH2O, LiMn2O4, and Li 1.6 Mn 1.6 O4, Li 1.33 Mn 1.67 O4, Li2TiO3, Li4Ti5O 12 One or more of them.

3. The lithium adsorbent particles according to claim 1, characterized in that, The lithium adsorbent precursor powder has a particle size of 0.1-100 μm.

4. The lithium adsorbent particles according to claim 3, characterized in that, The lithium adsorbent precursor powder has a particle size of 1-50 μm.

5. The lithium adsorbent particles according to claim 1, characterized in that, The mass ratio of the lithium adsorbent precursor powder to the polymer binder is 5 to 50:

1.

6. The lithium adsorbent particles according to claim 5, characterized in that, The mass ratio of the lithium adsorbent precursor powder to the polymer binder is 5 to 20:

1.

7. The lithium adsorbent particles according to claim 1, characterized in that, The amount of pore-forming agent used is 0.1-5 wt% of the mass of the lithium adsorbent precursor powder.

8. A method for preparing lithium adsorbent particles according to any one of claims 1-7, characterized in that, The steps include the following: (1) Mix lithium adsorbent precursor powder, polypeptide, polymer binder, organic solvent and pore-forming agent evenly to obtain a mixture; (2) The mixture is solidified, dried, crushed and sieved to obtain a lithium adsorbent semi-finished product; (3) The lithium adsorbent semi-finished product is post-treated with water to obtain granular lithium adsorbent.

9. The method for preparing lithium adsorbent particles according to claim 8, characterized in that, In step (1), the organic solvent is selected from one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, chloroform, dichloroethane, and ethyl acetate.

10. The method for preparing lithium adsorbent particles according to claim 9, characterized in that, The amount of organic solvent used is 50-100% of the total mass of lithium adsorbent precursor powder, polypeptide, and polymer binder.

11. The method for preparing lithium adsorbent particles according to claim 8, characterized in that, The mixing temperature in step (1) is 80-120℃ and the mixing time is 1-5h.

12. The method for preparing lithium adsorbent particles according to claim 8, characterized in that, In step (2), the particle size of the lithium adsorbent semi-finished product obtained by crushing and sieving is 0.5 mm to 3.0 mm.

13. The method for preparing lithium adsorbent particles according to claim 8, characterized in that, In step (3), the post-processing temperature is 25-45°C and the time is 12-48h.

14. The method for preparing lithium adsorbent particles according to claim 13, characterized in that, The post-processing is accompanied by stirring at a rate of 20-120 r / min.

15. The application of the lithium adsorbent particles according to any one of claims 1-7 or the lithium adsorbent particles prepared by the preparation method according to any one of claims 8-14 in the field of lithium extraction from salt lakes.

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