Modified aluminum-based lithium extraction adsorbent, and preparation method therefor and use thereof

Abstract

A modified aluminum-based lithium extraction adsorbent, and a preparation method therefor and the use thereof. The preparation method comprises the following steps: (1) mixing an aluminum-based adsorbent with a dihydrogen phosphate solution, and reacting same to obtain a modified adsorbent slurry; and (2) mixing the modified adsorbent slurry with a curing agent, and granulating the resulting mixture at a high temperature to obtain the modified aluminum-based lithium extraction adsorbent. The preparation method can improve the strength of the adsorbent, reduce adsorbent poisoning and prolong the service life of the adsorbent.

Description

A modified aluminum-based lithium extraction adsorbent and its preparation method and application Technical Field

[0001] The present application relates to the technical field of lithium extraction from salt lakes, for example, a modified aluminum-based lithium extraction adsorbent and its preparation method and application. Background Art

[0002] With the booming new energy industry and the rapid expansion of the lithium-battery-based power vehicle and electrochemical energy storage markets, demand for lithium resources is increasing. Salt lakes in my country's Qinghai and Tibet regions are rich in lithium resources. However, these salt lakes have a high magnesium-to-lithium ratio and low lithium content, making adsorption methods more suitable. One of the core materials in this method is a lithium adsorbent that specifically absorbs lithium ions from brine.

[0003] Powdered lithium adsorbents are easily lost during the lithium extraction process, so an appropriate granulation molding process is required to ensure the economy and long-term operation stability of the lithium adsorbent.

[0004] CN111804270A discloses an aluminum-based lithium adsorbent and a preparation method thereof. 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 the inducer and the target product have the same acid radical ion; then adding a soluble aluminum salt solution to the mixed solution to react, and then stirring to crystallize.

[0005] CN116829257A discloses an aluminum-based lithium adsorbent and a preparation method thereof. The preparation method of the aluminum-based lithium adsorbent comprises the following steps: mixing aluminum chloride and sodium hydroxide solution and heating the mixture to react to obtain a precursor; mixing the obtained precursor with lithium chloride, adding MoS2, and ball milling to obtain the aluminum-based lithium adsorbent.

[0006] The adsorbent prepared by the above scheme has a low lithium adsorption capacity. In order to increase the contact area between the adsorbent and the brine, the adsorbent is usually pore-formed. However, the porous adsorbent has low strength and is easily broken during pore formation and lithium extraction, which affects the service life of the adsorbent.

[0007] Summary of the Invention

[0008] 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.

[0009] The present application provides a modified aluminum-based lithium extraction adsorbent, a preparation method and application thereof. The present application prepares an aluminum-based lithium extraction adsorbent with surface phosphate modified, which improves the strength of the adsorbent while reducing adsorbent poisoning and increasing the service life of the adsorbent.

[0010] In a first aspect, the present application provides a method for preparing a modified aluminum-based lithium extraction adsorbent, the preparation method comprising the following steps:

[0011] (1) mixing an aluminum-based adsorbent with a dihydrogen phosphate solution to react and obtain a modified adsorbent slurry;

[0012] (2) The modified adsorbent slurry is mixed with a curing agent, and subjected to high-temperature granulation treatment to obtain the modified aluminum-based lithium extraction adsorbent.

[0013] The present application uses a dihydrogen phosphate solution to modify the surface of an aluminum-based adsorbent, and high-temperature granulation is used to generate aluminum phosphate, so that the PO bond with a shorter bond length replaces part of the Al-OH bond in the adsorbent to form a more stable PO-Al-OH structure. Therefore, the strength of the adsorbent can be improved, making it difficult to break during the granulation process. The aluminum phosphate on the surface can inhibit the entry of carbonate into the adsorbent to a certain extent through electrostatic repulsion and place-occupancy, thereby reducing carbonate poisoning of the adsorbent and increasing the service life of the adsorbent. The modified adsorbent slurry can be directly granulated without the need for an external binder, which can reduce the production cost of lithium extraction companies. The aluminum phosphate generated after the curing agent is solidified can increase the strength of the porous adsorbent, thereby extending the service life of the adsorbent.

[0014] In one embodiment, the aluminum-based adsorbent in step (1) comprises a porous aluminum-based adsorbent.

[0015] The aluminum-based adsorbent described in this application is a complex of aluminum hydroxide and lithium salt. The dihydrogen phosphate reacts with aluminum hydroxide to obtain aluminum phosphate. The reaction equation is as follows (taking sodium dihydrogen phosphate as an example): NaH2PO4+Al(OH)3→Al(H2PO4)3+NaOH

[0016] In one embodiment, the porous aluminum-based adsorbent is prepared by the following method:

[0017] The lithium salt, the aluminum salt, the precipitant and the surfactant are mixed with the solvent to obtain a mixed solution, and the mixed solution is reacted in a water bath to obtain the porous aluminum-based adsorbent.

[0018] In one embodiment, the lithium salt includes any one of lithium chloride, lithium sulfate, lithium nitrate, lithium acetate, or a combination of at least two of lithium acetate.

[0019] In one embodiment, the aluminum salt includes any one of aluminum nitrate, aluminum chloride, or aluminum sulfate, or a combination of at least two thereof.

[0020] In one embodiment, the precipitant includes any one of urea, ammonia water, sodium hydroxide, potassium hydroxide or lithium hydroxide, or a combination of at least two thereof.

[0021] In one embodiment, the surfactant includes any one of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, or hexadecyltrimethylammonium bromide, or a combination of at least two thereof.

[0022] In one embodiment, the molar ratio of the surfactant to the aluminum ion in the aluminum salt is 1:(30-50), for example, 1:30, 1:35, 1:40, 1:45 or 1:50.

[0023] In one embodiment, the pH of the mixed solution is 4.5-5, for example, 4.5, 4.6, 4.8, 4.9 or 5.

[0024] In one embodiment, the concentration of lithium ions in the mixed solution is 0.1 to 1 mol / L, for example, 0.1 mol / L, 0.2 mol / L, 0.5 mol / L, 0.8 mol / L or 1 mol / L.

[0025] In one embodiment, the concentration of aluminum ions in the mixed solution is 0.1 to 0.5 mol / L, for example, 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L or 0.5 mol / L.

[0026] In one embodiment, the temperature of the water bath reaction is 80-100°C, for example, 80°C, 85°C, 90°C, 95°C or 100°C.

[0027] In one embodiment, the water bath reaction time is 10 to 30 hours, for example, 10 hours, 15 hours, 20 hours, 25 hours or 30 hours.

[0028] In one embodiment, the water bath reaction is followed by water washing and drying.

[0029] In one embodiment, the dihydrogen phosphate solution in step (1) comprises a sodium dihydrogen phosphate solution.

[0030] In one embodiment, the concentration of the dihydrogen phosphate solution is 0.05 to 0.1 mol / L, for example, 0.05 mol / L, 0.06 mol / L, 0.08 mol / L, 0.09 mol / L or 0.1 mol / L.

[0031] In one embodiment, the solid-to-liquid ratio of the aluminum-based adsorbent to the dihydrogen phosphate solution is 0.5 to 2 g / mL, for example, 0.5 g / mL, 0.8 g / mL, 1 g / mL, 1.5 g / mL or 2 g / mL.

[0032] In one embodiment, the molar ratio of aluminum ions in the aluminum-based adsorbent to phosphate in the dihydrogen phosphate solution is (1-6):1, for example: 1:1, 2:1, 3:1, 5:1 or 6:1.

[0033] In one embodiment, the reaction time is 10 to 30 minutes, for example, 10 minutes, 16 minutes, 20 minutes, 25 minutes or 30 minutes.

[0034] In one embodiment, the curing agent in step (2) includes aluminum hydroxide and / or iron oxide.

[0035] In one embodiment, the mass ratio of aluminum phosphate to curing agent in the modified adsorbent slurry is (5-8):1, for example: 5:1, 5.5:1, 6:1, 7:1 or 8:1.

[0036] In one embodiment, the atmosphere of the high-temperature granulation treatment in step (2) includes water vapor.

[0037] The purpose of using water vapor as the atmosphere in the high-temperature granulation process described in the present application is to inhibit the decomposition of aluminum hydroxide. The reaction equations involved in the high-temperature granulation process are as follows: Al(H2PO4)3+Al(OH)3→Al(HP2O7)·2.5H2O; Al(HP2O7)·2.5H2O→AlPO4; Al(H2PO4)3+Fe2O3→Al(HP2O7)·2.5H2O+Fe(HP2O7)·2.5H2O; Al(HP2O7)·2.5H2O+Fe(HP2O7)·2.5H2O→AlPO4+FePO4.

[0038] Aluminum dihydrogen phosphate has low activity with aluminum hydroxide and / or iron oxide, so the adhesive viscosity is large, the curing reaction is complete, the structure is intact, and aluminum phosphate is generated during the reaction, further improving the stability of the adsorbent. The reaction temperature of aluminum dihydrogen phosphate with aluminum hydroxide is relatively low, about 200°C, and the reaction temperature with iron oxide is relatively high, which needs to be controlled at about 800°C.

[0039] In one embodiment, the curing agent is aluminum hydroxide, and the high-temperature granulation process includes one-step granulation and two-step granulation.

[0040] In one embodiment, the curing agent is iron oxide, and the high-temperature granulation includes one-step granulation, two-step granulation and three-step granulation.

[0041] In one embodiment, the temperature of the one-step granulation is 150-200°C, for example, 150°C, 160°C, 180°C, 190°C or 200°C.

[0042] In one embodiment, the one-step granulation time is 0.5 to 1 h, for example, 0.5 h, 0.6 h, 0.8 h, 0.9 h or 1 h.

[0043] In one embodiment, the temperature of the second-step granulation is 220-250°C, for example, 220°C, 225°C, 230°C, 240°C or 250°C.

[0044] In one embodiment, the time for the two-step granulation is 0.5 to 1 h, for example, 0.5 h, 0.6 h, 0.8 h, 0.9 h or 1 h.

[0045] In one embodiment, the temperature of the three-step granulation is 700-900°C, for example, 700°C, 750°C, 800°C, 850°C or 900°C.

[0046] In one embodiment, the three-step granulation time is 3 to 5 hours, for example: 30°C, 3.50°C, 40°C, 4.50°C or 50°C.

[0047] In a second aspect, the present application provides a modified aluminum-based lithium extraction adsorbent, which is prepared by the method described in the first aspect.

[0048] In a third aspect, the present application provides an application of the modified aluminum-based lithium extraction adsorbent as described in the second aspect, wherein the modified aluminum-based lithium extraction adsorbent is used for extracting lithium from salt lakes.

[0049] Compared with the related art, this application has the following beneficial effects:

[0050] (1) The preparation method of the modified aluminum-based lithium extraction adsorbent described in the present application is simple, and no binder needs to be added during the preparation process, thereby reducing production costs. The obtained lithium extraction adsorbent has high strength and is not easy to break during the granulation process. In addition, the aluminum phosphate on the surface of the adsorbent can reduce carbonate poisoning and increase the service life of the adsorbent.

[0051] (2) The adsorption capacity of the adsorbent prepared in the present application can reach above 8.52 mg / g, and the capacity retention rate can reach above 87.55% after 100 cycles.

[0052] Still other aspects will become apparent upon reading and understanding the accompanying drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] 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.

[0054] FIG1 is a SEM image of the modified aluminum-based lithium extraction adsorbent prepared in Example 1.

[0055] FIG2 is an XRD diagram of the modified aluminum-based lithium extraction adsorbent obtained in Example 1. DETAILED DESCRIPTION

[0056] The technical solution of the present application 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 application and should not be regarded as specific limitations of the present application.

[0057] Example 1

[0058] This embodiment provides a modified aluminum-based lithium extraction adsorbent, and the preparation method of the modified aluminum-based lithium extraction adsorbent is as follows:

[0059] (1) lithium chloride, aluminum chloride, ammonia water and sodium lauryl sulfate are mixed with water to obtain a mixed solution, wherein the molar ratio of the surfactant to the aluminum ion is 1:40; the lithium ion concentration in the mixed solution is 0.5 mol / L, the aluminum ion concentration is 0.3 mol / L, the pH of the mixed solution is controlled to be 4.6, and the reaction is carried out in a water bath at 90° C. for 20 hours. The solid obtained after the reaction is washed with water and dried to obtain a porous aluminum-based adsorbent. The porous aluminum-based adsorbent is added to a sodium dihydrogen phosphate solution with a concentration of 0.07 mol / L and reacted for 15 minutes. The solid-liquid ratio is 1 g / ml, and the molar ratio of sodium dihydrogen phosphate to aluminum ion is 1:4 to obtain a modified adsorbent slurry;

[0060] (2) The modified adsorbent slurry is mixed with iron oxide according to the mass ratio of aluminum dihydrogen phosphate to curing agent in the slurry of 7:1, and high-temperature granulation is carried out in a water vapor atmosphere. The temperature is raised to 200°C and kept warm for 0.8h, then raised to 250°C and kept warm for 0.8h, and then raised to 800°C and kept warm for 4h to obtain the modified aluminum-based lithium extraction adsorbent.

[0061] The SEM image of the modified aluminum-based lithium extraction adsorbent is shown in Figure 1. As can be seen from Figure 1, the surface morphology of the prepared adsorbent is irregular, and the surface layer has flaky aluminum phosphate with a size of 1 to 5 μm, indicating that the modified aluminum-based lithium extraction adsorbent has been successfully synthesized.

[0062] The XRD pattern of the modified aluminum-based lithium extraction adsorbent is shown in Figure 2. It can be seen from Figure 2 that the peak position of the synthesized adsorbent X-ray diffraction curve is basically consistent with the characteristic peak of the LiCl·2Al(OH)3·xH2O standard card. At the same time, the X-ray diffraction curve of the adsorbent shows a characteristic peak of aluminum phosphate at 2θ=9.6°, indicating that LiCl·2Al(OH)3·xH2O and aluminum phosphate are composited to form a modified aluminum-based lithium extraction adsorbent.

[0063] Example 2

[0064] This embodiment provides a modified aluminum-based lithium extraction adsorbent, and the preparation method of the modified aluminum-based lithium extraction adsorbent is as follows:

[0065] (1) lithium nitrate, aluminum nitrate, sodium hydroxide and sodium dodecyl sulfate are mixed with water to obtain a mixed solution, wherein the molar ratio of surfactant to aluminum ion is 1:30; the lithium ion concentration and aluminum ion concentration in the mixed solution are 0.1 mol / L and 0.1 mol / L, the pH of the mixed solution is controlled to be 4.8, and the reaction is carried out in a water bath at 80°C for 30 hours. The solid obtained after the reaction is washed with water and dried to obtain a porous aluminum-based adsorbent, and the porous aluminum-based adsorbent is added to a sodium dihydrogen phosphate solution with a concentration of 0.05 mol / L to react for 10 minutes, the solid-liquid ratio is 0.5 g / ml, and the molar ratio of sodium dihydrogen phosphate to aluminum ion is 1:2, to obtain a modified adsorbent slurry;

[0066] (2) The modified adsorbent slurry is mixed with aluminum hydroxide according to a mass ratio of aluminum dihydrogen phosphate to curing agent in the slurry of 5:1, and high-temperature granulation is performed in a water vapor atmosphere. The temperature is raised to 150°C and kept warm for 1 hour, and then raised to 220°C and kept warm for 1 hour to obtain the modified aluminum-based lithium extraction adsorbent.

[0067] Example 3

[0068] This embodiment provides a modified aluminum-based lithium extraction adsorbent, and the preparation method of the modified aluminum-based lithium extraction adsorbent is as follows:

[0069] (1) lithium sulfate, aluminum sulfate, sodium hydroxide and hexadecyltrimethylammonium bromide are mixed with water to obtain a mixed solution, wherein the molar ratio of the surfactant to the aluminum ion is 1:50; the lithium ion concentration in the mixed solution is 1 mol / L, the aluminum ion concentration is 0.5 mol / L, the pH of the mixed solution is controlled to be 5, and the mixture is reacted in a water bath at 100° C. for 10 hours, the solid obtained after the reaction is washed with water, and dried to obtain a porous aluminum-based adsorbent, and the porous aluminum-based adsorbent is added to a sodium dihydrogen phosphate solution with a concentration of 0.1 mol / L to react for 30 minutes, the solid-liquid ratio is 2 g / ml, and the molar ratio of sodium dihydrogen phosphate to aluminum ion is 1:6, to obtain a modified adsorbent slurry;

[0070] (2) The modified adsorbent slurry is mixed with aluminum hydroxide according to the mass ratio of aluminum dihydrogen phosphate to curing agent in the slurry of 8:1, and high-temperature granulation is carried out in a water vapor atmosphere. The temperature is raised to 200°C and kept warm for 0.5h, and then raised to 250°C and kept warm for 0.5h to obtain the modified aluminum-based lithium extraction adsorbent.

[0071] Example 4

[0072] The only difference between this embodiment and embodiment 1 is that the molar ratio of sodium dihydrogen phosphate to aluminum ion is 1:1, and other conditions and parameters are exactly the same as those in embodiment 1.

[0073] Example 5

[0074] The only difference between this embodiment and embodiment 1 is that the molar ratio of sodium dihydrogen phosphate to aluminum ion is 1:8, and other conditions and parameters are exactly the same as those in embodiment 1.

[0075] Example 6

[0076] The only difference between this embodiment and embodiment 1 is that the mass ratio of aluminum dihydrogen phosphate to curing agent is 3:1, and other conditions and parameters are exactly the same as those in embodiment 1.

[0077] Example 7

[0078] The only difference between this embodiment and embodiment 1 is that the mass ratio of aluminum dihydrogen phosphate to curing agent is 10:1, and other conditions and parameters are exactly the same as those in embodiment 1.

[0079] Example 8

[0080] The only difference between this embodiment and embodiment 1 is that the high-temperature granulation in step (2) is carried out under a nitrogen atmosphere, and the other conditions and parameters are exactly the same as those in embodiment 1.

[0081] Comparative Example 1

[0082] The only difference between this comparative example and Example 1 is that in step (1), sodium dihydrogen phosphate is replaced by phosphoric acid, and in step (2), phenolic resin is used as a binder. Other conditions and parameters are exactly the same as in Example 1.

[0083] Comparative Example 2

[0084] This comparative example provides a modified aluminum-based lithium extraction adsorbent, and the preparation method of the modified aluminum-based lithium extraction adsorbent is as follows:

[0085] (1) lithium chloride, aluminum chloride, ammonia water, and sodium lauryl sulfate are mixed with water to obtain a mixed solution, wherein the molar ratio of the surfactant to the aluminum ion is 1:40; the lithium ion concentration in the mixed solution is 0.5 mol / L, the aluminum ion concentration is 0.3 mol / L, the pH of the mixed solution is controlled to be 4.6, and the mixture is reacted in a water bath at 90° C. for 20 hours. The solid obtained after the reaction is washed with water and dried to obtain a porous aluminum-based adsorbent;

[0086] (2) 200 g of porous aluminum-based adsorbent, 50 g of polyvinylidene fluoride, 12.5 g of polyvinyl pyrrolidone, and 350 gg of N,N-dimethylformamide were added into a planetary mixer and mixed evenly. The mixture was granulated by an extruder and then washed with water to obtain a lithium adsorbent.

[0087] Performance testing:

[0088] The adsorbents prepared in the examples and comparative examples were used to extract lithium from brine with a Li+ concentration of 500 ppm for 15 h. 20 g of deionized water and 2 g of the lithium adsorbent were mixed and delithiation was carried out at room temperature for 10 h. The brine concentrations before and after adsorption were measured, and the adsorption capacity was calculated according to the following formula.

[0089] The adsorption capacity of the adsorbent is: Q = V (C0-C) / m;

[0090] Q is the adsorption capacity, mg / g; V is the volume of the adsorption liquid, L; m is the mass of the adsorbent, g; C0 and C are the lithium ion concentrations in the brine before and after adsorption, respectively, mg / L.

[0091] The ratio of the adsorption capacity after 100 cycles to the initial adsorption capacity is the capacity retention rate after 100 cycles. The test results are shown in Table 1:

[0092] Table 1

[0093] As can be seen from Table 1, from Examples 1-3, the adsorption capacity of the adsorbent prepared in the present application can reach above 8.52 mg / g, and the capacity retention rate can reach above 87.55% after 100 cycles.

[0094] By comparing Example 1 with Examples 4-5, it can be seen that in the preparation process of the modified aluminum-based lithium extraction adsorbent described in the present application, the molar ratio of dihydrogen phosphate to aluminum ions will affect its performance. The molar ratio of dihydrogen phosphate to aluminum ions is controlled at 1:2~6, and the performance of the modified aluminum-based lithium extraction adsorbent is better. If the amount of dihydrogen phosphate added is too large, it will cause excessive raw materials, and a large amount of raw materials will not react and cause waste. If the amount of dihydrogen phosphate added is too small, the amount of aluminum phosphate formed is small, and the modification effect on the lithium extraction adsorbent is not good.

[0095] By comparing Example 1 with Examples 6-7, it can be seen that in the preparation process of the modified aluminum-based lithium extraction adsorbent described in the present application, the mass ratio of aluminum dihydrogen phosphate to the curing agent in the slurry will affect its performance. By controlling the mass ratio of aluminum dihydrogen phosphate to the curing agent at 5 to 8:1, the performance of the modified aluminum-based lithium extraction adsorbent obtained is better. If the amount of curing agent added is too large, it will affect the lithium extraction capacity of the adsorbent. If the amount of curing agent added is too small, the strength of the adsorbent after granulation will be reduced, affecting the cycle stability.

[0096] From the comparison between Example 1 and Example 8, it can be seen that the use of water vapor as the high-temperature granulation atmosphere in the present application can inhibit the decomposition of aluminum hydroxide and avoid the reduction of adsorption capacity.

[0097] By comparison of Example 1 and Comparative Examples 1-2, it can be seen that the present application performs surface modification on the adsorbent so that the PO bonds with shorter bond lengths replace part of the Al-OH bonds in the adsorbent to form a more stable PO-Al-OH structure. The aluminum phosphate on the surface can inhibit the entry of carbonate into the adsorbent to a certain extent through electrostatic repulsion and space occupation, thereby reducing carbonate poisoning of the adsorbent and increasing the service life of the adsorbent. The surface modification of the aluminum-based adsorbent using dihydrogen phosphate and the high-temperature granulation to generate aluminum phosphate can increase the strength of the adsorbent without using a binder, making it less likely to break during the granulation process.

[0098] The applicant declares that the above is only a specific implementation method of the present application, but the protection scope of the present application is not limited thereto. Technical personnel in the relevant technical field should understand that any changes or substitutions that can be easily thought of by technical personnel in the relevant technical field within the technical scope disclosed in this application fall within the protection scope and disclosure scope of this application.

Claims

1. A preparation method of a modified lithium extraction adsorbent based on aluminum, comprising the following steps: (1) Mix an aluminum-based adsorbent with a dihydrogen phosphate solution, and react to obtain a modified adsorbent slurry; (2) Mix the modified adsorbent slurry with a curing agent, and perform high-temperature granulation treatment to obtain the modified lithium extraction adsorbent based on aluminum.

2. The preparation method according to claim 1, wherein The aluminum-based adsorbent in step (1) includes a porous aluminum-based adsorbent.

3. The preparation method according to claim 2, wherein, The porous aluminum-based adsorbent is prepared by the following method: Mix a lithium salt, an aluminum salt, a precipitating agent, and a surfactant with a solvent to obtain a mixed solution, and perform a water bath reaction to obtain the porous aluminum-based adsorbent.

4. The preparation method according to claim 3, wherein, The lithium salt includes any one or a combination of at least two of lithium chloride, lithium sulfate, lithium nitrate, lithium acetate, or lithium acetate; Optionally, the aluminum salt includes any one or a combination of at least two of aluminum nitrate, aluminum chloride, or aluminum sulfate.

5. The preparation method according to claim 3 or 4, wherein The precipitating agent includes any one or a combination of at least two of urea, ammonia water, sodium hydroxide, potassium hydroxide, or lithium hydroxide.

6. The preparation method according to any one of claims 3-5, wherein, The surfactant includes any one or a combination of at least two of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, or cetyltrimethylammonium bromide.

7. The preparation method according to any one of claims 3-6, wherein, The molar ratio of the surfactant to aluminum ions in the aluminum salt is 1:(30-50); Optionally, the pH of the mixed solution is 4.5-5; Optionally, the concentration of lithium ions in the mixed solution is 0.1-1 mol / L; Optionally, the concentration of aluminum ions in the mixed solution is 0.1-0.5 mol / L.

8. The preparation method according to any one of claims 3-7, wherein, The temperature of the water bath reaction is 80-100 °C; Optionally, the time of the water bath reaction is 10-30 h; Optionally, after the water bath reaction, washing with water and drying are performed.

9. The preparation method according to any one of claims 1-8, wherein, The dihydrogen phosphate solution in step (1) includes a sodium dihydrogen phosphate solution; Optionally, the concentration of the dihydrogen phosphate solution is 0.05-0.1 mol / L; Optionally, the solid-liquid ratio of the aluminum-based adsorbent to the dihydrogen phosphate solution is 0.5-2 g / mL; Optionally, the molar ratio of aluminum ions in the aluminum-based adsorbent to phosphate radicals in the dihydrogen phosphate solution is (1-6):1; Optionally, the reaction time is 10-30 min.

10. The preparation method according to any one of claims 1-9, wherein, The curing agent in step (2) includes aluminum hydroxide and / or iron oxide; Optionally, the mass ratio of aluminum phosphate salt to the curing agent in the modified adsorbent slurry is (5-8):

1.

11. The preparation method according to any one of claims 1-10, wherein, The atmosphere of the high-temperature granulation treatment in step (2) includes water vapor; Optionally, the curing agent is aluminum hydroxide, and the high-temperature granulation treatment includes one-step granulation and two-step granulation; Optionally, the curing agent is iron oxide, and the high-temperature granulation treatment includes one-step granulation, two-step granulation, and three-step granulation.

12. The preparation method according to claim 11, wherein, The temperature of the one-step granulation is 150-200 °C; Optionally, the time of the one-step granulation is 0.5-1 h.

13. The preparation method according to claim 11 or 12, wherein, The temperature of the two-step granulation is 220-250 °C; Optionally, the time of the two-step granulation is 0.5-1 h.

14. The preparation method according to any one of claims 11-13, wherein, The temperature of the three-step granulation is 700-900 °C; Optionally, the time of the three-step granulation is 3-5 h.

15. A modified lithium-extracting adsorbent based on aluminum, wherein, The modified lithium extraction adsorbent based on aluminum is prepared by the method according to any one of claims 1-14.

16. Use of the modified lithium extraction adsorbent based on aluminum as described in claim 15, wherein, The modified lithium extraction adsorbent based on aluminum is used for extracting lithium from salt lakes.

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