Adsorbent for lithium extraction, and preparation method therefor and use thereof

Abstract

The present disclosure provides an adsorbent for lithium extraction, and a preparation method therefor and the use thereof. The adsorbent for lithium extraction comprises at least one hollow penetrating columnar adsorbent for lithium extraction, and the hollow penetrating columnar adsorbent for lithium extraction is made of an aluminum-based adsorbent and a polymer. The adsorbent for lithium extraction in the present disclosure can achieve a capillary action by virtue of the unique structure thereof; brine to be subjected to lithium extraction can be separated from brine, which is not subjected to lithium extraction, during the lithium extraction process; the brine in a hollow position can be discharged by means of a negative pressure after lithium extraction; and the concentration of the brine can be prevented from being reduced during the lithium extraction process.

Description

A lithium extraction adsorbent and its preparation method and application Technical Field

[0001] The present invention belongs to the technical field of lithium extraction from salt lakes and relates to a lithium extraction adsorbent and a preparation method and application thereof. Background Art

[0002] With the increasing demand for energy storage in various industries, including portable electronic devices, large-scale grid storage, and electric vehicles, the demand for lithium is also rising. Lithium exists naturally in various chemical forms, primarily as ores and salt lakes. Salt lakes account for approximately 70% of lithium resources. Current methods for extracting lithium from salt lakes include salt pan methods, electrochemical deintercalation, extraction, and adsorption. The salt pan and extraction methods are restricted due to their significant environmental and ecological impacts. The technical maturity of the electrochemical deintercalation method is still far from meeting industrial requirements. Adsorption methods include molecular sieve adsorption and ion sieve adsorption. The adsorbents used for lithium extraction from chloride salt lakes are primarily aluminum molecular sieves, which are currently the most mature adsorbents for lithium extraction.

[0003] CN111804270A discloses an aluminum-based lithium adsorbent and its preparation method. The preparation method comprises: mixing and dissolving a lithium salt and an inducer in water to prepare an alkaline mixed solution; the inducer is a non-aluminum salt and has the same acid radical ion as the target product; then adding a soluble aluminum salt solution to the mixed solution for reaction, followed by stirring and crystallization. The present disclosure utilizes this preparation method to obtain an aluminum-based lithium adsorbent with a layered structure.

[0004] CN116272843A discloses a mesoporous aluminum-based lithium adsorbent and its preparation method and application. The preparation method comprises: step 1) preparation of a precursor of the mesoporous aluminum-based lithium adsorbent; ； Step 2) forming and granulating; Step 3) washing and drying to obtain the mesoporous lithium adsorbent. The obtained mesoporous aluminum-based lithium adsorbent is a spherical porous material.

[0005] During the process of lithium extraction by the lithium extraction adsorbent prepared by the above scheme, the brine concentration will gradually decrease, which will reduce the lithium extraction efficiency. In addition, the adsorbent and brine need to be separated during the process of lithium extraction by adsorption, and separation by filtration is relatively complicated.

[0006] Summary of the Invention

[0007] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0008] The purpose of the present disclosure is to provide a lithium extraction adsorbent, a preparation method and application thereof. The lithium extraction adsorbent can realize capillary action due to its unique structure. During the lithium extraction process, it can separate the brine to be extracted with lithium from the brine that has not been extracted with lithium. After lithium extraction, negative pressure can be used to remove the brine in the hollow position, thereby avoiding the reduction of brine concentration during the lithium extraction process.

[0009] To achieve this purpose, the present disclosure adopts the following technical solutions:

[0010] In a first aspect, the present disclosure provides a lithium extraction adsorbent, which includes at least one hollow through-columnar lithium extraction adsorbent, and the material of the hollow through-columnar lithium extraction adsorbent includes an aluminum-based adsorbent and a polymer.

[0011] The lithium extraction adsorbent disclosed herein has a hollow, through-columnar structure (similar to a capillary structure, with a through-columnar interior and a columnar outer wall). Capillary action can be used to adsorb brine into the hollow space. After lithium extraction, negative pressure can be used to remove the brine from the hollow space, thereby preventing a decrease in brine concentration during the lithium extraction process. The lithium extraction adsorbent does not need to be flushed by brine during the lithium extraction process, which can slow down the dissolution of the adsorbent and improve the cyclic stability of the adsorbent.

[0012] In one embodiment, the length of the hollow through-columnar lithium extraction adsorbent is 10 to 50 cm, for example, 10 cm, 20 cm, 30 cm, 40 cm or 50 cm.

[0013] In one embodiment, the inner diameter of the hollow through-columnar lithium extraction adsorbent is 0.1 to 2.5 mm, for example, 0.1 mm, 0.5 mm, 1 mm, 1.5 mm or 2.5 mm.

[0014] In one embodiment, the wall thickness of the hollow columnar lithium extraction adsorbent is 0.05 to 1.5 mm.

[0015] In one embodiment, the polymer includes any one or a combination of at least two of polytetrafluoroethylene, polyvinylidene fluoride, polyurethane, polystyrene or polycarbonate.

[0016] In one embodiment, the mass ratio of the polymer to the aluminum-based adsorbent is (1-2):1, for example: 1:1, 1.2:1, 1.5:1, 1.8:1 or 2:1, etc.

[0017] In one embodiment, a binder is provided between adjacent hollow through-columnar lithium extraction adsorbents.

[0018] The lithium extraction adsorbent disclosed in the present invention includes but is not limited to a hollow through-columnar structure. A plurality of hollow through-columnar lithium extraction adsorbents can be adhered together side by side as needed to simultaneously extract lithium. Adhesives need to be provided between adjacent hollow through-columnar lithium extraction adsorbents to fix the structure.

[0019] In one embodiment, the binder includes any one of polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl alcohol or polyurethane, or a combination of at least two thereof.

[0020] In a second aspect, the present disclosure provides a method for preparing the lithium extraction adsorbent as described in the first aspect, the preparation method comprising the following steps:

[0021] (1) mixing a polymer, an aluminum-based adsorbent, and a solvent to obtain an adsorbent slurry;

[0022] (2) The adsorbent slurry is placed in a syringe and the lithium extraction adsorbent is obtained by 3D printing.

[0023] The present invention uses 3D printing to control the length, pore size, wall thickness and other parameters of the lithium extraction adsorbent, and prepares a hollow columnar lithium extraction adsorbent that can realize capillary phenomenon, thereby avoiding the problem of difficult solid-liquid separation of traditional adsorbents during the lithium extraction process.

[0024] In one embodiment, the solvent in step (1) comprises any one of butyl acetate, N-methylpyrrolidone, tetrahydrofuran or dimethylformamide, or a combination of at least two thereof.

[0025] In one embodiment, the mass fraction of the aluminum-based adsorbent in the adsorbent slurry is 10-20%, for example, 10%, 12%, 15%, 18% or 20%.

[0026] In one embodiment, the trajectory of the 3D printed syringe nozzle in step (2) is controlled by a Nordson robot.

[0027] In one embodiment, the air supply pressure for 3D printing is 200-500 psi, for example, 200 psi, 250 psi, 300 psi, 400 psi, or 500 psi.

[0028] In one embodiment, the printing speed of the 3D printing is 1 to 3 mm / s, for example, 1 mm / s, 1.5 mm / s, 2 mm / s, 2.5 mm / s or 3 mm / s.

[0029] In one embodiment, a drying process is performed after the 3D printing.

[0030] In one embodiment, after the drying treatment, the binder and N-methylpyrrolidone are mixed in a mass ratio of (2 to 3): 1 (for example, 2: 1, 2.2: 1, 2.5: 1, 2.8: 1 or 3: 1, etc.) to prepare a slurry, and the slurry is coated on the surface of the hollow through-columnar lithium extraction adsorbent and bonded to another hollow through-columnar lithium extraction adsorbent, and the steps are repeated to obtain a combined lithium extraction adsorbent.

[0031] In a third aspect, the present disclosure provides a method for extracting lithium, comprising the following steps:

[0032] placing one end portion of the lithium extraction adsorbent as described in the first aspect in brine, filling the brine into the hollow portion of the lithium extraction adsorbent by capillary action, and taking out the lithium extraction adsorbent to perform a static lithium extraction reaction;

[0033] placing the lithium extraction adsorbent after the lithium extraction reaction in a negative pressure device to suck out the brine to obtain an adsorbent to be delithiated;

[0034] The adsorbent to be delithiated is subjected to a lithium removal treatment to obtain a lithium-rich solution and a lithium-extracting adsorbent.

[0035] The lithium extraction method disclosed in the present invention can separate the brine to be extracted with lithium from the brine that has not been extracted with lithium. After lithium extraction, the brine in the hollow position can be removed by negative pressure, and the brine concentration will not be reduced during the lithium extraction process, thereby ensuring the lithium extraction efficiency of the adsorbent.

[0036] In one embodiment, the standing lithium extraction reaction time is 5 to 20 hours, for example, 5 hours, 8 hours, 10 hours, 15 hours or 20 hours.

[0037] In one embodiment, the pressure of the negative pressure device is -5 to -15 kPa, for example: -5 kPa, -8 kPa, -10 kPa, -12 kPa or -15 kPa.

[0038] In one embodiment, the delithiation process includes mixed lithium extraction and / or capillary lithium extraction.

[0039] In one embodiment, the mixed lithium extraction comprises mixing the adsorbent to be delithiated with pure water, and stirring to obtain a lithium-rich solution and a lithium-extracting adsorbent.

[0040] In one embodiment, the capillary lithium extraction includes placing one end portion of the adsorbent to be delithiated in pure water, filling the hollow portion of the adsorbent to be delithiated with pure water, taking out the adsorbent to be delithiated for a static delithiation reaction, placing the lithium-extracting adsorbent after the delithiation reaction in a negative pressure device, and sucking out the lithium-rich solution to obtain a lithium-extracting adsorbent and a lithium-rich solution.

[0041] In one embodiment, the delithiation reaction time is 1 to 5 hours, for example, 1 hour, 2 hours, 3 hours, 4 hours or 5 hours.

[0042] Compared with the prior art, the present disclosure has the following beneficial effects:

[0043] (1) The lithium extraction adsorbent disclosed in the present invention can realize capillary action due to its unique structure. During the lithium extraction process, it can separate the brine to be extracted with lithium from the brine that has not been extracted with lithium. After lithium extraction, negative pressure can be used to remove the brine in the hollow position, which can avoid the reduction of brine concentration during the lithium extraction process.

[0044] (2) The adsorption capacity of the lithium extraction adsorbent disclosed in the present invention can reach above 9.31 mg / g, and the capacity retention rate can reach above 97.8% after 100 cycles.

[0045] Still other aspects will become apparent upon reading and understanding the accompanying drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The accompanying drawings are used to provide a further understanding of the technical solution of this article and constitute a part of the specification. Together with the embodiments of this application, they are used to explain the technical solution of this article and do not constitute a limitation on the technical solution of this article.

[0047] FIG1 is a schematic structural diagram of a lithium extraction adsorbent according to an embodiment of the present disclosure.

[0048] FIG2 is a schematic diagram of an apparatus used in the preparation process of a lithium extraction adsorbent according to an embodiment of the present disclosure.

[0049] FIG3 is a schematic diagram of a process of using a lithium extraction adsorbent according to an embodiment of the present disclosure to extract lithium. DETAILED DESCRIPTION

[0050] The technical solution of the present disclosure is further described below through specific implementation methods. Those skilled in the art should understand that the embodiments are only used to help understand the present disclosure and should not be regarded as specific limitations of the present disclosure.

[0051] Example 1

[0052] This embodiment provides a lithium extraction adsorbent, which is prepared by the following method:

[0053] (1) dissolving polytetrafluoroethylene in butyl acetate, adding an aluminum-based adsorbent, and stirring to obtain an adsorbent slurry, wherein the mass fraction of the aluminum-based adsorbent in the adsorbent slurry is 15 wt %, and the mass ratio of polytetrafluoroethylene to the aluminum-based adsorbent is 1:1;

[0054] (2) The adsorbent slurry is loaded into a syringe, and the syringe is connected to the coaxial nozzle through a transfer tube (the schematic diagram of the device is shown in Figure 2). The movement trajectory of the nozzle is controlled by a Nordson robot (Nordson JR-V2000, USA). The air supply pressure is 300psi, the printing speed is 2mm / s, and a hollow through-column adsorbent with an inner diameter of 2mm, a wall thickness of 1mm, and a length of 15cm is prepared by 3D printing. The printed product is dried, polytetrafluoroethylene and N-methylpyrrolidone are mixed in a mass ratio of 2:1 to prepare a slurry, and the hollow through-column adsorbent is bonded and combined to obtain the lithium extraction adsorbent.

[0055] The structural schematic diagram of the lithium extraction adsorbent is shown in FIG1 .

[0056] Example 2

[0057] This embodiment provides a lithium extraction adsorbent, which is prepared by the following method:

[0058] (1) dissolving polyvinylidene fluoride in butyl acetate, adding an aluminum-based adsorbent, and stirring to obtain an adsorbent slurry, wherein the mass fraction of the aluminum-based adsorbent in the adsorbent slurry is 20 wt %, and the mass ratio of polyvinylidene fluoride to the aluminum-based adsorbent is 1.5:1;

[0059] (2) The adsorbent slurry is loaded into a syringe, and the syringe is connected to the coaxial nozzle via a transfer tube (the schematic diagram of the device is shown in FIG2 ). The movement trajectory of the nozzle is controlled by a Nordson robot (Nordson JR-V2000, USA). The air supply pressure is 200 psi, and the printing speed is 1 mm / s. A hollow through-column adsorbent with an inner diameter of 1.5 mm, a wall thickness of 0.5 mm, and a length of 10 cm is prepared by 3D printing. The printed product is dried, and polytetrafluoroethylene and N-methylpyrrolidone are mixed in a mass ratio of 2.5:1 to prepare a slurry. The hollow through-column adsorbent is bonded and combined to obtain the lithium extraction adsorbent.

[0060] The structural schematic diagram of the lithium extraction adsorbent is shown in FIG1 .

[0061] Example 3

[0062] This embodiment provides a lithium extraction adsorbent, which is prepared by the following method:

[0063] (1) dissolving polyurethane in N-methylpyrrolidone, adding an aluminum-based adsorbent, and stirring to obtain an adsorbent slurry, wherein the mass fraction of the aluminum-based adsorbent in the adsorbent slurry is 10 wt %, and the mass ratio of polyurethane to aluminum-based adsorbent is 2:1;

[0064] (2) The adsorbent slurry is loaded into a syringe, and the syringe is connected to the coaxial nozzle through a transfer tube (the schematic diagram of the device is shown in Figure 2). The movement trajectory of the nozzle is controlled by a Nordson robot (Nordson JR-V2000, USA). The air supply pressure is 500psi, the printing speed is 3mm / s, and a hollow through-column adsorbent with an inner diameter of 2.2mm, a wall thickness of 0.85mm, and a length of 50cm is prepared by 3D printing. The printed product is dried, and polytetrafluoroethylene and N-methylpyrrolidone are mixed in a mass ratio of 3.5:1 to prepare a slurry. The hollow through-column adsorbent is bonded and combined to obtain the lithium extraction adsorbent.

[0065] The structural schematic diagram of the lithium extraction adsorbent is shown in FIG1 .

[0066] Example 4

[0067] The only difference between this embodiment and embodiment 1 is that the inner diameter of the hollow through-columnar lithium extraction adsorbent is 3 mm, and the other conditions and parameters are exactly the same as those in embodiment 1.

[0068] Example 5

[0069] The only difference between this embodiment and embodiment 1 is that the mass ratio of the polymer (polytetrafluoroethylene) to the aluminum-based adsorbent is 0.5:1, and the other conditions and parameters are exactly the same as those in embodiment 1.

[0070] Example 6

[0071] The only difference between this embodiment and embodiment 1 is that the mass ratio of the polymer (polytetrafluoroethylene) to the aluminum-based adsorbent is 3:1, and the other conditions and parameters are exactly the same as those in embodiment 1.

[0072] Comparative Example 1

[0073] This comparative example provides a lithium extraction adsorbent, which is prepared by the following method:

[0074] Aluminum chloride, lithium chloride and water are mixed and ultrasonically stirred to obtain a mixed aluminum-lithium solution. Alkaline solution is then gradually added to the aluminum-lithium solution to perform a precipitation reaction, and the pH value at the reaction end point is controlled to be 6. The aluminum-based lithium adsorbent precursor precipitate is then filtered and separated from the liquid, and then dried and crushed to obtain the aluminum-based lithium adsorbent precursor.

[0075] Mixing chlorinated polyvinyl chloride and N-methylpyrrolidone, stirring until completely dissolved, to obtain a composite resin glue;

[0076] 15 wt% of the obtained composite resin glue and 28 wt% of the aluminum-based lithium adsorbent precursor were mixed and stirred to obtain a blend slurry;

[0077] The blended slurry is solidified and granulated by a granulating device, and then sieved to obtain the lithium extraction adsorbent.

[0078] Comparative Example 2

[0079] The only difference between this comparative example and Example 1 is that a solid columnar adsorbent is prepared by 3D printing, and the other conditions and parameters are exactly the same as those in Example 1.

[0080] Comparative Example 3

[0081] The only difference between this comparative example and Example 1 is that the prepared hollow cylindrical adsorbent has an inner diameter of 5 mm, an outer diameter of 6 mm, and a length of 50 cm. During lithium extraction, an external casing is added to continuously apply negative pressure so that the brine fills the interior of the hollow cylindrical adsorbent.

[0082] Application Example 1

[0083] This application example provides a lithium extraction method, which includes the following steps:

[0084] (1) One end of the lithium extraction adsorbent prepared in Example 1 was placed in brine with a lithium content of 273 mg / L. The brine was filled into the hollow part of the lithium extraction adsorbent by capillary action. The lithium extraction adsorbent was taken out and allowed to stand for 10 hours to perform a lithium extraction reaction.

[0085] (2) placing the lithium extraction adsorbent after the lithium extraction reaction in a negative pressure device at a pressure of -8 kPa, sucking out the low-lithium brine in the hollow part to obtain an adsorbent with no brine in the hollow part, repeating step (1) until the difference in brine concentration before and after the lithium extraction operation is less than 1%, and obtaining an adsorbent to be delithiated. The schematic diagram of the lithium extraction process is shown in Figure 3;

[0086] (3) placing one end of the adsorbent to be delithiated in pure water, and using capillary action to allow the pure water to fill the hollow part of the adsorbent. After standing for 2 hours to delithiate, the adsorbent is placed in a negative pressure device with a pressure of -8 kPa, and the lithium solution in the hollow part is sucked out to obtain an adsorbent without pure water in the hollow part. Repeat step (1) until the lithium ion concentration in the brine after the delithiation operation is less than 20 mg / L, thereby obtaining a completely delithiated adsorbent and a lithium-rich solution, and the completely delithiated adsorbent is reused in step (1).

[0087] Application Example 2

[0088] The only difference between this application example and application example 1 is that the lithium extraction adsorbent is prepared using Example 2, and in step (3) of application example 1, the delithiation method directly mixes the adsorbent to be delithiated with pure water for delithiation. The other conditions and parameters are exactly the same as those in application example 1.

[0089] Application Example 3

[0090] The only difference between this application example and application example 1 is that the lithium extraction adsorbent is prepared using Example 3, and the other conditions and parameters are exactly the same as those in application example 1.

[0091] Application Example 4

[0092] The only difference between this application example and application example 1 is that the lithium extraction adsorbent is prepared using Example 4, and the other conditions and parameters are exactly the same as those in application example 1.

[0093] Application Example 5

[0094] The only difference between this application example and application example 1 is that the lithium extraction adsorbent is prepared using Example 5, and the other conditions and parameters are exactly the same as those in application example 1.

[0095] Application Example 6

[0096] The only difference between this application example and application example 1 is that the lithium extraction adsorbent is prepared using Example 6, and the other conditions and parameters are exactly the same as those in application example 1.

[0097] Comparative Application Example 1

[0098] This comparative application example provides a lithium extraction method, which includes the following steps:

[0099] The aluminum-based lithium adsorbent prepared in Comparative Example 1 was loaded into a chromatography column, and brine with a lithium content of 273 mg / L was subjected to a one-way adsorption-washing-analysis evaluation. The brine adsorption flow rate was 2.6 Bv / h, the pure water washing flow rate was 3.5 Bv / h, the washing volume was 0.8 Bv, the analysis flow rate was 4 Bv / h, and deionized water was used at 20°C for 1 hour.

[0100] Comparative Application Example 2

[0101] The only difference between this comparative application example and application example 1 is that the lithium extraction adsorbent is prepared using comparative example 2, and the other conditions and parameters are exactly the same as those of application example 1.

[0102] Comparative Application Example 3

[0103] The only difference between this comparative application example and application example 1 is that the lithium extraction adsorbent prepared in comparative example 3 is used, and a negative pressure of 10 kPa is continuously applied during lithium extraction.

[0104] Performance testing:

[0105] The test results of the application examples and comparative application examples are shown in Table 1:

[0106] Table 1

[0107] As can be seen from Table 1, from Examples 1-3, the adsorption capacity of the lithium extraction adsorbent disclosed in the present disclosure can reach above 9.31 mg / g, and the capacity retention rate can reach above 97.8% after 100 cycles.

[0108] From the comparison between Example 1 and Example 4, it can be seen that the inner diameter of the hollow through-columnar lithium extraction adsorbent in the lithium extraction adsorbent disclosed in the present invention will affect the capillary effect, and thus affect the performance of the prepared lithium extraction adsorbent. If the inner diameter of the hollow through-columnar lithium extraction adsorbent is too large, the capillary effect is poor, and it is difficult to make all the adsorbent contact with the brine, which affects the adsorption capacity. If the inner diameter is too small, the adsorption efficiency is affected.

[0109] By comparing Example 1 with Examples 5-6, it can be seen that in the preparation process of the lithium extraction adsorbent described in the present disclosure, the mass ratio of the polymer to the aluminum-based adsorbent will affect its performance. The mass ratio of the polymer to the aluminum-based adsorbent is controlled at 1 to 2:1, and the lithium extraction adsorbent is better. If the proportion of the polymer is too high, it will affect the proportion of lithium extraction active substances in the lithium extraction adsorbent and affect the adsorption capacity. If the proportion of the polymer is too low, it will be difficult to perform 3D printing, which will affect the cycle stability.

[0110] A comparison of Example 1 and Comparative Example 1 shows that the adsorption capacity of the lithium extraction adsorbent disclosed herein is significantly higher than that of conventional aluminum-based adsorbents. Furthermore, due to its hollow, columnar structure, brine can be adsorbed into the hollow region by capillary action. After lithium extraction, the brine in the hollow region can be removed by negative pressure, thus preventing a decrease in brine concentration during the lithium extraction process. The lithium extraction adsorbent does not need to be flushed by brine during the lithium extraction process, which can slow down the dissolution loss of the adsorbent and improve its cyclic stability.

[0111] As can be seen from the comparison between Example 1 and Comparative Example 2, the lithium extraction adsorbent disclosed in the present disclosure, with its unique hollow through-columnar structure, can use capillary action to adsorb brine to the hollow position. After lithium extraction, the brine in the hollow position can be removed by negative pressure, which can avoid the continuous decrease in brine concentration during the lithium extraction process. It is easy to distinguish between lithium-extracted brine and non-lithium-extracted brine, which is conducive to targeted treatment of different brines. If a solid lithium extraction adsorbent is used, it can only play the role of adsorbing and extracting lithium, which is no different from a conventional lithium extraction adsorbent and cannot avoid the continuous decrease in brine concentration during the lithium extraction process.

[0112] From the comparison between Example 1 and Comparative Example 3, it can be seen that the lithium extraction adsorbent disclosed in the present invention can utilize capillary action to adsorb brine to the hollow position. If adsorbents of other sizes are used, external force is required to make the brine fill the interior of the hollow tubular adsorbent, which will generate additional energy consumption and is not conducive to energy and cost savings.

Claims

1. A lithium extraction adsorbent, comprising at least one hollow through-columnar lithium extraction adsorbent, and the material of the hollow through-columnar lithium extraction adsorbent comprises an aluminum-based adsorbent and a polymer.

2. The lithium extraction adsorbent according to claim 1, wherein, The length of the hollow through-column lithium extraction adsorbent is 10 to 50 cm.

3. The lithium extraction adsorbent according to claim 1 or 2, wherein, The inner diameter of the hollow through-column lithium extraction adsorbent is 0.1 to 2.5 mm.

4. The lithium extraction adsorbent according to any one of claims 1-3, wherein, The wall thickness of the hollow through-column lithium extraction adsorbent is 0.05 to 1.5 mm.

5. The lithium extraction adsorbent according to any one of claims 1-4, wherein, The polymer includes any one or a combination of at least two of polytetrafluoroethylene, polyvinylidene fluoride, polyurethane, polystyrene, or polycarbonate.

6. The lithium extraction adsorbent according to any one of claims 1-5, wherein, The mass ratio of the polymer to the aluminum-based adsorbent is (1 to 2):

1.

7. The lithium extraction adsorbent according to any one of claims 1-6, wherein, A binder is provided between adjacent hollow through-column lithium extraction adsorbents.

8. The lithium extraction adsorbent according to claim 7, wherein, The binder includes any one or a combination of at least two of polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl alcohol, or polyurethane.

9. A preparation method of the lithium extraction adsorbent according to any one of claims 1-8, comprising the following steps: (1) Mix the polymer, the aluminum-based adsorbent, and a solvent to obtain an adsorbent slurry; (2) Place the adsorbent slurry in a syringe and obtain the lithium extraction adsorbent by 3D printing.

10. The preparation method according to claim 9, wherein, The solvent in step (1) includes any one or a combination of at least two of butyl acetate, N-methylpyrrolidone, tetrahydrofuran, or dimethylformamide.

11. The preparation method according to claim 9 or 10, wherein, The mass fraction of the aluminum-based adsorbent in the adsorbent slurry is 10 to 20%.

12. The preparation method according to any one of claims 9-11, wherein, The trajectory of the 3D printing syringe nozzle in step (2) is controlled by a Nordson robot; Optionally, the air supply pressure for 3D printing is 200 to 500 psi; Optionally, the printing speed for 3D printing is 1 to 3 mm / s; Optionally, drying treatment is performed after 3D printing; Optionally, after the drying treatment, the binder and N-methylpyrrolidone are mixed into a slurry according to a mass ratio of (2 to 3):1, the slurry is coated on the surface of the hollow through-column lithium extraction adsorbent and bonded to another hollow through-column lithium extraction adsorbent, and the steps are repeated to obtain a combined lithium extraction adsorbent.

13. A lithium extraction method, comprising the following steps: Place one end portion of the lithium extraction adsorbent according to any one of claims 1-7 in brine, and use capillary action to fill the hollow portion of the lithium extraction adsorbent with the brine, then take out the lithium extraction adsorbent for static lithium extraction reaction; Place the lithium extraction adsorbent after the lithium extraction reaction in a negative pressure device to suck out the brine to obtain a lithium-depleted adsorbent; Perform lithium-depletion treatment on the lithium-depleted adsorbent to obtain a lithium-rich solution and a lithium extraction adsorbent.

14. The lithium extraction method according to claim 13, wherein, The time for the static lithium extraction reaction is 5 to 20 h; Optionally, the pressure of the negative pressure device is -5 to -15 kPa.

15. The lithium extraction method according to claim 13 or 14, wherein, The lithium-depletion treatment includes mixed lithium extraction and / or capillary lithium extraction; Optionally, the mixed lithium extraction includes mixing the lithium-depleted adsorbent with pure water and stirring to obtain a lithium-rich solution and a lithium extraction adsorbent; Optionally, the capillary lithium extraction includes placing one end portion of the lithium-depleted adsorbent in pure water, filling the hollow portion of the lithium-depleted adsorbent with the pure water, taking out the lithium-depleted adsorbent for static lithium-depletion reaction, placing the lithium extraction adsorbent after the lithium-depletion reaction in a negative pressure device, and sucking out the lithium-rich solution to obtain a lithium extraction adsorbent and a lithium-rich solution; Optionally, the time for the lithium-depletion reaction is 1 to 5 h.

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