A lithium extraction adsorbent, a preparation method and application thereof

Abstract

The present disclosure provides a lithium extraction adsorbent, a preparation method and application thereof. The lithium extraction adsorbent comprises at least one hollow through columnar lithium extraction adsorbent, and a material of the hollow through columnar lithium extraction adsorbent comprises an aluminum-based adsorbent and a polymer. The lithium extraction adsorbent can realize capillary action due to its unique structure, can separate the brine to be extracted from the brine not to be extracted in the lithium extraction process, and can remove the brine in the hollow position by using negative pressure after lithium extraction, so that the concentration of the brine can be prevented from being reduced in the lithium extraction process.

Description

TECHNICAL FIELD

[0001] The present disclosure 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

[0002] With the increasing demand for energy storage in various industries such as portable electronic devices, large-scale power grid storage and electric vehicles, the demand for lithium elements has also increased. Lithium exists in nature in various chemical forms, mainly in the form of ores and salt lakes, of which salt lakes account for about 70% of lithium resources. Current lithium extraction from salt lakes mainly includes salt field method, electrochemical deintercalation method, extraction method, adsorption method, etc. The salt field method and the extraction method are limited in use due to their large environmental and ecological impact. The electrochemical deintercalation method is difficult to achieve industrialization due to its technical maturity. The adsorption method includes molecular sieve adsorption method and ion sieve adsorption method. The adsorbent used for lithium extraction from chlorinated salt lakes is mainly aluminum-based molecular sieve adsorbent, which is the most mature lithium extraction adsorbent at present.

[0003] CN111804270A discloses an aluminum-based lithium adsorbent and a preparation method thereof. The preparation method includes: dissolving lithium salt and an inducing agent in water to prepare an alkaline mixed solution; the inducing agent is a non-aluminum salt, and the inducing agent has the same acid radical ion as the target product; then, a soluble aluminum salt solution is added to the mixed solution for reaction, and then stirring and crystallization are performed. The present disclosure obtains an aluminum-based lithium adsorbent with a layered structure by using the above preparation method.

[0004] CN116272843A discloses a mesoporous aluminum-based lithium adsorbent, a preparation method and application thereof. The preparation method includes: step 1) preparation of a mesoporous aluminum-based lithium adsorbent precursor; step 2) molding and granulation; and step 3) water washing and drying to obtain the mesoporous lithium adsorbent. The obtained mesoporous aluminum-based lithium adsorbent is a spherical porous material.

[0005] In the process of adsorbing and extracting lithium by the lithium extraction adsorbent prepared by the above scheme, the concentration of the brine will gradually decrease, which will reduce the lithium extraction efficiency. In addition, the adsorbent needs to be separated from the brine in the process of adsorbing and extracting lithium, and the separation by filtration is relatively complex. SUMMARY

[0006] The following is a summary of the subject matter of the detailed description herein. This summary is not intended to limit the scope of the claims.

[0007] The present disclosure aims to provide a lithium extraction adsorbent and a preparation method and application thereof. The lithium extraction adsorbent has a unique structure, can realize capillary action, can separate the brine to be extracted from the brine not to be extracted in the lithium extraction process, and can remove the brine in the hollow position by using negative pressure after lithium extraction, so as to avoid the decrease of the brine concentration in the lithium extraction process.

[0008] To achieve the above object, the present disclosure adopts the following technical solutions:

[0009] In a first aspect, the present disclosure provides a lithium extraction adsorbent, which comprises 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.

[0010] The lithium extraction adsorbent described in the present disclosure has a hollow-through columnar structure (i.e. a structure similar to a capillary tube, the inside of the tube is hollow, and the outer wall is columnar), which can utilize capillary action to adsorb brine to the hollow position, and after lithium extraction, the brine in the hollow position can be removed by negative pressure, thereby avoiding the reduction of brine concentration during lithium extraction. The lithium extraction adsorbent does not need to be flushed by brine during lithium extraction, which can slow down the dissolution loss of the adsorbent and improve the cycle stability of the adsorbent.

[0011] In an embodiment, the length of the hollow-through columnar lithium extraction adsorbent is 10-50 cm, for example, 10 cm, 20 cm, 30 cm, 40 cm or 50 cm, etc.

[0012] In an embodiment, the inner diameter of the hollow-through columnar lithium extraction adsorbent is 0.1-2.5 mm, for example, 0.1 mm, 0.5 mm, 1 mm, 1.5 mm or 2.5 mm, etc.

[0013] In an embodiment, the wall thickness of the hollow-through columnar lithium extraction adsorbent is 0.05-1.5 mm.

[0014] In an embodiment, the polymer comprises any one of polytetrafluoroethylene, polyvinylidene fluoride, polyurethane, polystyrene or polycarbonate, or a combination of at least two thereof.

[0015] In an 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.

[0016] In an embodiment, an adhesive is arranged between adjacent hollow-through columnar lithium extraction adsorbents.

[0017] The lithium extraction adsorbent described in the present disclosure comprises but is not limited to one hollow-through columnar structure, and multiple hollow-through columnar lithium extraction adsorbents can be adhered together side by side as needed for lithium extraction, and an adhesive needs to be arranged between adjacent hollow-through columnar lithium extraction adsorbents to fix the structure.

[0018] In an embodiment, the adhesive comprises any one of polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl alcohol or polyurethane, or a combination of at least two thereof.

[0019] In a second aspect, the present disclosure provides a preparation method of the lithium extraction adsorbent according to the first aspect, the preparation method comprising the following steps:

[0020] (1) mixing the polymer, the aluminum-based adsorbent and the solvent to obtain an adsorbent slurry;

[0021] (2) placing the adsorbent slurry in a syringe and obtaining the lithium extraction adsorbent by 3D printing.

[0022] The present disclosure can control the length, pore size, wall thickness and other parameters of the prepared lithium extraction adsorbent by 3D printing, and prepare a hollow through columnar lithium extraction adsorbent that can realize capillary phenomenon, thereby avoiding the problem of difficult solid-liquid separation of traditional adsorbents in the lithium extraction process.

[0023] In an embodiment, the solvent in step (1) comprises any one or a combination of at least two of butyl acetate, N-methyl pyrrolidone, tetrahydrofuran or dimethylformamide.

[0024] In an embodiment, the mass fraction of the aluminum-based adsorbent in the adsorbent slurry is 10-20%, for example, 10%, 12%, 15%, 18% or 20%, etc.

[0025] In an embodiment, the trajectory of the 3D printing syringe nozzle in step (2) is controlled by a Nordson robot.

[0026] In an embodiment, the gas supply pressure of the 3D printing is 200-500 psi, for example, 200 psi, 250 psi, 300 psi, 400 psi or 500 psi, etc.

[0027] In an embodiment, the printing speed of the 3D printing is 1-3 mm / s, for example, 1 mm / s, 1.5 mm / s, 2 mm / s, 2.5 mm / s or 3 mm / s, etc.

[0028] In an embodiment, the 3D printing is followed by a drying process.

[0029] In an embodiment, after the drying process, the binder and N-methyl pyrrolidone are mixed at a mass ratio of (2-3):1 (for example, 2:1, 2.2:1, 2.5:1, 2.8:1 or 3:1, etc.) to prepare a slurry, the slurry is coated on the surface of the hollow through columnar lithium extraction adsorbent and another hollow through columnar lithium extraction adsorbent to bond them, and the step is repeated to obtain a combined lithium extraction adsorbent.

[0030] In a third aspect, the present disclosure provides a lithium extraction method, the lithium extraction method comprising the following steps:

[0031] placing one end of the lithium extraction adsorbent as described in the first aspect in the brine, filling the brine into the hollow part of the lithium extraction adsorbent by capillary action, taking out the lithium extraction adsorbent for static lithium extraction reaction;

[0032] placing the lithium extraction adsorbent after the lithium extraction reaction in a negative pressure device to suck out the brine, and obtaining the lithium extraction adsorbent to be delithiated;

[0033] delithiating the lithium extraction adsorbent to be delithiated to obtain a lithium-rich solution and the lithium extraction adsorbent.

[0034] The lithium extraction method of the present disclosure can separate the brine to be extracted from the brine not to be extracted, and the brine in the hollow position can be removed by negative pressure after lithium extraction, so that the concentration of the brine is not reduced during the lithium extraction process, and the lithium extraction efficiency of the adsorbent is ensured.

[0035] In one embodiment, the static lithium extraction reaction time is 5-20h, for example, 5h, 8h, 10h, 15h or 20h, etc.

[0036] In one embodiment, the pressure of the negative pressure device is-5 to-15kPa, for example, -5kPa, -8kPa, -10kPa, -12kPa or-15kPa, etc.

[0037] In one embodiment, the delithiation treatment includes mixed lithium extraction and / or capillary lithium extraction.

[0038] In one embodiment, the mixed lithium extraction includes mixing the lithium extraction adsorbent to be delithiated with pure water, and stirring to obtain a lithium-rich solution and the lithium extraction adsorbent.

[0039] In one embodiment, the capillary lithium extraction includes placing one end of the lithium extraction adsorbent to be delithiated in pure water, filling the pure water into the hollow part of the lithium extraction adsorbent to be delithiated, taking out the lithium extraction adsorbent to be delithiated for static delithiation reaction, and placing the lithium extraction adsorbent after the delithiation reaction in a negative pressure device to suck out the lithium-rich solution, and obtaining the lithium extraction adsorbent and the lithium-rich solution.

[0040] In one embodiment, the delithiation reaction time is 1-5h, for example, 1h, 2h, 3h, 4h or 5h, etc.

[0041] Compared with the prior art, the present disclosure has the following beneficial effects:

[0042] (1) The lithium extraction adsorbent of the present disclosure can realize capillary action due to its unique structure, and can separate the brine to be extracted from the brine not to be extracted during the lithium extraction process. After lithium extraction, the brine in the hollow position can be removed by negative pressure, and the concentration of the brine can be prevented from being reduced during the lithium extraction process.

[0043] (2) The adsorption capacity of the lithium extraction adsorbent disclosed in the present disclosure can reach 9.31 mg / g or more, and the capacity retention rate after 100 cycles can reach 97.8% or more.

[0044] Other aspects can become apparent from reading the specification and drawings. BRIEF DESCRIPTION OF DRAWINGS

[0045] The accompanying drawings are included to provide a further understanding of the technical solutions of the present disclosure, and constitute a part of the specification, and are used together with the embodiments of the present disclosure to explain the technical solutions of the present disclosure, and do not constitute a limitation on the technical solutions of the present disclosure.

[0046] Figure 1 is a structural schematic diagram of the lithium extraction adsorbent according to an embodiment of the present disclosure.

[0047] Figure 2 is a schematic diagram of a device used in the preparation process of the lithium extraction adsorbent according to an embodiment of the present disclosure.

[0048] Figure 3 is a process schematic diagram of the lithium extraction adsorbent for lithium extraction according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0049] The technical solutions of the present disclosure will be further described by specific embodiments. It should be understood by those skilled in the art that the embodiments are only used to help understand the present disclosure, and should not be regarded as a specific limitation on the present disclosure.

[0050] Embodiment 1

[0051] The present embodiment provides a lithium extraction adsorbent, which is prepared by the following method:

[0052] (1) Dissolve polytetrafluoroethylene in butyl acetate, add aluminum-based adsorbent, and stir to obtain an adsorbent slurry, wherein the mass fraction of aluminum-based adsorbent in the adsorbent slurry is 15 wt%, and the mass ratio of polytetrafluoroethylene to aluminum-based adsorbent is 1:1;

[0053] (2) The adsorbent slurry is loaded into a syringe, and the syringe is connected to a coaxial nozzle through a transfer tube (device schematic diagram as shown in Figure 2 The movement trajectory of the nozzle is controlled by a Nordson robot (Nordson JR-V2000, USA). The gas supply pressure is 300 psi, the printing speed is 2 mm / s, and a hollow through columnar adsorbent with an inner diameter of 2 mm, a wall thickness of 1 mm, and a length of 15 cm is prepared by 3D printing. The printed product is dried, polytetrafluoroethylene and N-methyl pyrrolidone are mixed at a mass ratio of 2:1 to prepare a slurry, and the hollow through columnar adsorbent is adhered and combined to obtain the lithium extraction adsorbent.

[0054] A schematic diagram of the lithium extraction adsorbent is shown in Figure 1 .

[0055] Example 2

[0056] The present example provides a lithium extraction adsorbent, which is prepared by the following method:

[0057] (1) Dissolve polyvinylidene fluoride in butyl acetate, add aluminum-based adsorbent, and stir to obtain an adsorbent slurry, wherein the mass fraction of aluminum-based adsorbent in the adsorbent slurry is 20 wt%, and the mass ratio of polyvinylidene fluoride to aluminum-based adsorbent is 1.5:1;

[0058] (2) Load the adsorbent slurry into a syringe, and connect the syringe to a coaxial nozzle through a transfer tube (a schematic diagram of the device is shown in Figure 2 ). The motion trajectory of the nozzle is controlled by a Nordson robot (Nordson JR-V2000, USA). The gas supply pressure is 200 psi, the printing speed is 1 mm / s, and a hollow through columnar 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. Dry the printed product, mix polytetrafluoroethylene and N-methyl pyrrolidone at a mass ratio of 2.5:1 to prepare a slurry, and stick the hollow through columnar adsorbent to obtain the lithium extraction adsorbent.

[0059] A schematic diagram of the lithium extraction adsorbent is shown in Figure 1 .

[0060] Example 3

[0061] The present example provides a lithium extraction adsorbent, which is prepared by the following method:

[0062] (1) Dissolve polyurethane in N-methyl pyrrolidone, add aluminum-based adsorbent, and stir to obtain an adsorbent slurry, wherein the mass fraction of aluminum-based adsorbent in the adsorbent slurry is 10 wt%, and the mass ratio of polyurethane to aluminum-based adsorbent is 2:1;

[0063] (2) Load the adsorbent slurry into a syringe, and connect the syringe to a coaxial nozzle through a transfer tube (a schematic diagram of the device is shown in Figure 2 ). The motion trajectory of the nozzle is controlled by a Nordson robot (Nordson JR-V2000, USA). The gas supply pressure is 500 psi, the printing speed is 3 mm / s, and a hollow through columnar adsorbent with an inner diameter of 2.2 mm, a wall thickness of 0.85 mm, and a length of 50 cm is prepared by 3D printing. Dry the printed product, mix polytetrafluoroethylene and N-methyl pyrrolidone at a mass ratio of 3.5:1 to prepare a slurry, and stick the hollow through columnar adsorbent to obtain the lithium extraction adsorbent.

[0064] The schematic structure of the lithium extraction adsorbent is shown in Figure 1

[0065] Example 4

[0066] The difference between this example and Example 1 is only that the inner diameter of the hollow through-column lithium extraction adsorbent is 3 mm, and other conditions and parameters are exactly the same as those in Example 1.

[0067] Example 5

[0068] The difference between this example and Example 1 is only that the mass ratio of the polymer (polytetrafluoroethylene) to the aluminum-based adsorbent is 0.5:1, and other conditions and parameters are exactly the same as those in Example 1.

[0069] Example 6

[0070] The difference between this example and Example 1 is only that the mass ratio of the polymer (polytetrafluoroethylene) to the aluminum-based adsorbent is 3:1, and other conditions and parameters are exactly the same as those in Example 1.

[0071] Comparative Example 1

[0072] This comparative example provides a lithium extraction adsorbent, which is prepared by the following method:

[0073] Aluminum chloride, lithium chloride and water are mixed to obtain a mixed aluminum-lithium solution, and then an alkali solution is gradually added to the aluminum-lithium solution to perform a precipitation reaction, and the pH at the end of the reaction is controlled to be 6; then the aluminum-based lithium adsorbent precursor precipitate is separated from the liquid by filtration, and then dried and crushed to obtain the aluminum-based lithium adsorbent precursor;

[0074] Polyvinyl chloride chloride is mixed with N-methyl pyrrolidone, and stirred until completely dissolved to obtain a composite resin glue;

[0075] The obtained composite resin glue 15wt% and aluminum-based lithium adsorbent precursor 28wt% are mixed in a ratio of 15wt%:28wt% and stirred uniformly to obtain a blended slurry;

[0076] The blended slurry is solidified and granulated by a granulating device, and then sieved to obtain the lithium extraction adsorbent.

[0077] Comparative Example 2

[0078] The difference between this comparative example and Example 1 is only that a solid columnar adsorbent is prepared by 3D printing, and other conditions and parameters are exactly the same as those in Example 1.

[0079] Comparative Example 3

[0080] ​The comparative example differs from example 1 only in 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. A sleeve is applied to continuously apply negative pressure during lithium extraction, so that the brine fills the inside of the hollow cylindrical adsorbent.

[0081] Application Example 1

[0082] The application example provides a lithium extraction method, which comprises the following steps:

[0083] (1) A part of the lithium extraction adsorbent prepared in example 1 is placed in brine with a lithium content of 273 mg / L, and the brine is filled into the hollow part of the lithium extraction adsorbent by capillary action. The lithium extraction adsorbent is taken out and allowed to stand for 10 h for lithium extraction reaction.

[0084] (2) The lithium extraction adsorbent after the lithium extraction reaction is placed in a negative pressure device with a pressure of -8 kPa, and the low-lithium brine in the hollow part is sucked out to obtain an adsorbent without brine in the hollow part. Repeat step (1) until the difference in brine concentration before and after lithium extraction is less than 1%, and obtain the adsorbent to be delithiated. The lithium extraction process is shown in Figure 3 .

[0085] (3) A part of the adsorbent to be delithiated is placed in pure water, and the pure water is filled into the hollow part of the adsorbent by capillary action. After standing for 2 h for delithiation, it is placed in a negative pressure device with a pressure of -8 kPa, and the lithium-containing 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 delithiation is less than 20 mg / L, and obtain the completely delithiated adsorbent and the lithium-rich solution. The completely delithiated adsorbent is reused in step (1).

[0086] Application Example 2

[0087] The application example differs from application example 1 only in that the lithium extraction adsorbent prepared in example 2 is used, and in step (3) of application example 1, the delithiation method directly mixes the adsorbent to be delithiated with pure water for delithiation. Other conditions and parameters are the same as those in application example 1.

[0088] Application Example 3

[0089] The application example differs from application example 1 only in that the lithium extraction adsorbent prepared in example 3 is used, and other conditions and parameters are the same as those in application example 1.

[0090] Application Example 4

[0091] The application example differs from application example 1 only in that the lithium extraction adsorbent prepared in example 4 is used, and other conditions and parameters are the same as those in application example 1.

[0092] Application Example 5

[0093] The application example differs from application example 1 only in that the lithium extraction adsorbent is prepared using Example 5, and other conditions and parameters are exactly the same as in application example 1.

[0094] Application Example 6

[0095] The application example differs from application example 1 only in that the lithium extraction adsorbent is prepared using Example 6, and other conditions and parameters are exactly the same as in application example 1.

[0096] Comparative Application Example 1

[0097] The comparative application example provides a lithium extraction method, which comprises the following steps:

[0098] The aluminum-based lithium adsorbent prepared in Comparative Example 1 is loaded into a chromatographic column, and a lithium-containing brine with a lithium content of 273 mg / L is subjected to one-way adsorption-washing-elution evaluation, the adsorption rate into the brine is 2.6 Bv / h, the washing rate into pure water is 3.5 Bv / h, the washing volume is 0.8 Bv, the elution rate is 4 Bv / h, and deionized water is used to elute the column at 20°C for 1 h.

[0099] Comparative Application Example 2

[0100] The comparative application example differs from application example 1 only in that the lithium extraction adsorbent is prepared using Comparative Example 2, and other conditions and parameters are exactly the same as in application example 1.

[0101] Comparative Application Example 3

[0102] The comparative application example differs from application example 1 only in that the lithium extraction adsorbent is prepared using Comparative Example 3, and a negative pressure of 10 kPa is continuously applied during lithium extraction.

[0103] Performance test:

[0104] The test results of the application examples and comparative application examples are shown in Table 1.

[0105] Table 1

[0106]

[0107]

[0108] As can be seen from Table 1, according to Examples 1-3, the adsorption capacity of the lithium extraction adsorbent described in the present disclosure can reach 9.31 mg / g or more, and the capacity retention rate after 100 cycles can reach 97.8% or more.

[0109] From the comparison of Example 1 and Example 4, it can be seen that the inner diameter of the hollow through columnar lithium extraction adsorbent in the present disclosure affects the capillary effect, and in turn affects 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, it is difficult to make all the adsorbents contact with the brine, which affects the adsorption capacity. If the inner diameter is too small, the adsorption efficiency is affected.

[0110] From the comparison of Example 1 and Example 5-6, it can be seen that the mass ratio of polymer to aluminum-based adsorbent in the preparation process of the lithium extraction adsorbent in the present disclosure affects its performance. If the mass ratio of polymer to aluminum-based adsorbent is controlled at 1-2:1, the prepared lithium extraction adsorbent has better effect. If the proportion of polymer is too high, it will affect the proportion of lithium extraction active substances in the lithium extraction adsorbent, affecting the adsorption capacity. If the proportion of polymer is too low, it is difficult to perform 3D printing, affecting the cycle stability.

[0111] From the comparison of Example 1 and Comparative Example 1, it can be seen that the adsorption capacity of the lithium extraction adsorbent in the present disclosure is significantly higher than that of the conventional aluminum-based adsorbent. Moreover, due to its hollow through columnar structure, the brine can be adsorbed to the hollow position by capillary action. After lithium extraction, the brine in the hollow position can be removed by negative pressure, which can avoid the decrease of brine concentration during lithium extraction. The lithium extraction adsorbent does not need to be flushed by brine during lithium extraction, which can slow down the dissolution loss of the adsorbent and improve the cycle stability of the adsorbent.

[0112] From the comparison of Example 1 and Comparative Example 2, it can be seen that the lithium extraction adsorbent in the present disclosure can utilize capillary action to adsorb brine to the hollow position by virtue of its unique hollow through columnar structure. After lithium extraction, the brine in the hollow position can be removed by negative pressure, which can avoid the continuous decrease of brine concentration during lithium extraction, easily distinguish the lithium-extracted brine from the non-lithium-extracted brine, and facilitate targeted treatment of different brines. If a solid lithium extraction adsorbent is used, it can only play a role in adsorbing lithium, which is no different from the conventional lithium extraction adsorbent, and cannot avoid the continuous decrease of brine concentration during lithium extraction.

[0113] From the comparison of Example 1 and Comparative Example 3, it can be seen that the lithium extraction adsorbent in the present disclosure can utilize capillary action to adsorb brine to the hollow position. If other size adsorbents are used, external force is needed to make the brine fill the inside of the hollow tubular adsorbent, which will produce additional energy consumption, which is not conducive to energy and cost saving.

Claims

1. A method of lithium extraction, wherein, The method comprises the following steps: One end of the lithium extraction adsorbent is placed in brine, and the brine is filled into the hollow part of the lithium extraction adsorbent by capillary action, and the lithium extraction adsorbent is taken out for static lithium extraction reaction; The lithium extraction adsorbent after the lithium extraction reaction is placed in a negative pressure device, and the brine is pumped out to obtain a lithium extraction adsorbent to be delithiated; The lithium extraction adsorbent to be delithiated is subjected to delithiation treatment to obtain a lithium-rich solution and a lithium extraction adsorbent; The lithium extraction adsorbent comprises 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 method for lithium extraction as claimed in claim 1, wherein, The static lithium extraction reaction time is 5-20 h.

3. The method for lithium extraction of claim 1, wherein, The pressure of the negative pressure device is-5 to-15 kPa.

4. The method for lithium extraction of claim 1, wherein, The delithiation treatment comprises mixed lithium extraction and / or capillary lithium extraction.

5. The method for lithium extraction as claimed in claim 4 wherein, The mixed lithium extraction comprises mixing the lithium extraction adsorbent to be delithiated with pure water, stirring to obtain a lithium-rich solution and a lithium extraction adsorbent.

6. The method for lithium extraction as claimed in claim 4 wherein, The capillary lithium extraction comprises placing one end of the lithium extraction adsorbent to be delithiated in pure water, filling the pure water into the hollow part of the lithium extraction adsorbent to be delithiated, taking out the lithium extraction adsorbent to be delithiated for static delithiation reaction, and placing the lithium extraction adsorbent after the delithiation reaction in a negative pressure device to pump out the lithium-rich solution to obtain a lithium extraction adsorbent and a lithium-rich solution.

7. The method for lithium extraction as claimed in claim 6 wherein, The delithiation reaction time is 1-5 h.

8. The method for lithium extraction as claimed in claim 1 wherein, The length of the hollow through columnar lithium extraction adsorbent is 10-50 cm.

9. The lithium extraction method of claim 1, wherein, The inner diameter of the hollow through columnar lithium extraction adsorbent is 0.1-2.5 mm.

10. The method for lithium extraction of claim 1, wherein, The wall thickness of the hollow through columnar lithium extraction adsorbent is 0.05-1.5 mm.

11. The method for lithium extraction as claimed in claim 1 wherein, The polymer comprises any one or a combination of at least two of polytetrafluoroethylene, polyvinylidene fluoride, polyurethane, polystyrene or polycarbonate.

12. The method for lithium extraction as claimed in claim 1 wherein, The mass ratio of the polymer to the aluminum-based adsorbent is (1-2):

1.

13. The method for lithium extraction of claim 1, wherein, An adjacent hollow through columnar lithium extraction adsorbent is provided with a bonding agent.

14. The method for lithium extraction as claimed in claim 13 wherein, The bonding agent comprises any one or a combination of at least two of polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl alcohol or polyurethane.

15. The lithium extraction method of claim 1, wherein the preparation method of the lithium extraction adsorbent comprises the following steps: (1) mixing a polymer, an aluminum-based adsorbent and a solvent to obtain an adsorbent slurry; (2) placing the adsorbent slurry in a syringe to obtain the lithium extraction adsorbent by 3D printing.

16. The method for lithium extraction as claimed in claim 15 wherein, The solvent of step (1) comprises any one or a combination of at least two of butyl acetate, N-methyl pyrrolidone, tetrahydrofuran or dimethylformamide.

17. The method for lithium extraction as claimed in claim 15 wherein, The mass fraction of the aluminum-based adsorbent in the adsorbent slurry is 10-20%.

18. The method for lithium extraction of claim 15, wherein, The trajectory of the 3D printing syringe nozzle of step (2) is controlled by a Nordson robot.

19. The method for lithium extraction of claim 15, wherein, The air supply pressure of the 3D printing is 200-500 psi.

20. The method for lithium extraction of claim 15, wherein, The printing speed of the 3D printing is 1-3 mm / s.

21. The method for lithium extraction as claimed in claim 15 wherein, The 3D printing is subjected to drying treatment.

22. The method for lithium extraction as claimed in claim 21 wherein, After the drying treatment, the bonding agent is mixed with N-methyl pyrrolidone at a mass ratio of (2-3):1 to prepare a slurry, the slurry is coated on the surface of the hollow through columnar lithium extraction adsorbent to bond with another hollow through columnar lithium extraction adsorbent, and the step is repeated to obtain a combined lithium extraction adsorbent.

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