Modified lithium extraction adsorbent, and preparation method and use therefor

Abstract

A modified lithium extraction adsorbent, and a preparation method and use therefor. The preparation method comprises the following steps: (1) mixing activated aluminum oxide with a lithium salt solution, and carrying out a heating reaction to obtain an adsorbent precursor; (2) mixing a phenyllithium solution with the adsorbent precursor, carrying out ultrasonic treatment, adding a chlorotriphenylmethane-containing solution, reacting to obtain a tetraphenylmethane-coated aluminum-based adsorbent; (3) carrying out plasma hydrophilic treatment on the tetraphenylmethane-coated aluminum-based adsorbent to obtain a modified lithium extraction adsorbent. The outer-layer modified layer of the modified lithium extraction adsorbent can improve the cycling stability of the adsorbent, and can physically adsorb lithium ions in the brine, such that the inner-layer adsorbent is protected while the adsorption capacity is not reduced.

Description

A modified 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 modified lithium extraction adsorbent and a preparation method and application thereof. Background Art

[0002] With the vigorous development of the new energy vehicle industry and the rapid development of advanced technologies such as aerospace, lithium and its compounds are increasingly valued, and the global demand for lithium resources is also increasing.

[0003] Currently, lithium mining relies primarily on lithium ore and salt lake brine, but lithium ore reserves are insufficient to meet the future development needs of related industries. Liquid lithium, which accounts for approximately 70% to 80% of total lithium resources, is a crucial strategic resource for alleviating lithium resource shortages. Therefore, effectively extracting liquid lithium has become a research hotspot.

[0004] Salt lake brine contains a large amount of Na, K, Mg and other ions, with complex composition and large differences in different regions. These characteristics increase the difficulty of extracting liquid lithium. Ion exchange adsorption is considered to be the most promising method for extracting lithium from salt lake brine, with the characteristics of simplicity, high selectivity and less pollution. The most studied lithium ion adsorbents at present are mainly manganese lithium ion sieves, titanium lithium ion sieves and aluminum salt lithium ion adsorbents. Aluminum salt lithium ion adsorbents are compounds formed by inserting lithium salts represented by lithium chloride into the Al(OH)3 layered molecular structure, and some Li is removed by washing with water. + The generated vacancies can selectively adsorb Li from lithium-containing solutions. + .

[0005] CN110975795A discloses a method for synthesizing a lithium-extracting adsorbent, which comprises dissolving a lithium source in a solvent containing a certain amount of additives, then adding a titanium source thereto and mixing them evenly to form a solid-liquid mixed state, and assisting the synthesis by drying treatment, so that the raw materials dry quickly and are fully mixed. After calcination, a lithium ion sieve precursor Li2TiO3 with uniform particle size distribution can be obtained; and a metatitanate-type lithium ion sieve H2TiO3 is obtained after acid elution of lithium from the precursor Li2TiO3.

[0006] CN114130375A discloses a method for preparing a film-like lithium ion sieve adsorbent, which includes the steps of 1) preparing a composite sol; 2) slurrying a lithium ion sieve precursor; 3) doping, blending, and ultrasonic homogenization; 4) casting and coating; 5) drying and peeling; 6) cross-linking; and 7) elution and displacement.

[0007] The structure of the lithium ion extraction lithium adsorbent prepared by the above method is easily corroded, and the high concentration of sulfate in the solution will have a great impact on the cyclic stability of the aluminum salt adsorbent.

[0008] Summary of the Invention

[0009] 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.

[0010] The purpose of the present disclosure is to provide a modified lithium extraction adsorbent, a preparation method and application thereof. The outer modified layer of the modified lithium extraction adsorbent prepared by the method described in the present disclosure can improve the cyclic stability of the adsorbent and can physically adsorb lithium ions in brine, thereby protecting the inner layer adsorbent without reducing the adsorption capacity.

[0011] To achieve this purpose, the present disclosure adopts the following technical solutions:

[0012] In a first aspect, the present disclosure provides a method for preparing a modified lithium extraction adsorbent, the preparation method comprising the following steps:

[0013] (1) Mixing activated alumina with a lithium salt solution and heating the mixture to react to obtain an adsorbent precursor;

[0014] (2) mixing a phenyllithium solution with the adsorbent precursor, and after ultrasonic treatment, adding a triphenylmethane solution to react to obtain a tetraphenylmethane-coated aluminum-based adsorbent;

[0015] (3) The tetraphenylmethane-coated aluminum-based adsorbent is subjected to plasma hydrophilic treatment to obtain the modified lithium extraction adsorbent.

[0016] The present invention uses phenyllithium and triphenylmethane to modify a crystalline aluminum salt lithium ion adsorbent. The benzene ring of the outer modified layer can attract lithium ions, thereby improving the adsorption efficiency of lithium ions and the lithium extraction efficiency. The tetramethylbenzene ring is an electron-donating group, which can attract the binder required for granulation during the granulation process, and is more conducive to the preparation of adsorbent particles with better cycle stability.

[0017] In one embodiment, the solute of the lithium salt solution in step (1) includes lithium chloride.

[0018] In one embodiment, the solvent of the lithium salt solution includes water.

[0019] In one embodiment, the mass concentration of the lithium salt solution is 15-30%, for example, 15%, 18%, 20%, 25% or 30%.

[0020] In one embodiment, the molar ratio of activated alumina to lithium salt is 1:(1-1.2), for example, 1:1, 1:1.05, 1:1.1, 1:1.15 or 1:1.2.

[0021] In one embodiment, the temperature of the heating reaction in step (1) is 90-100°C, for example, 90°C, 92°C, 95°C, 98°C or 100°C.

[0022] In one embodiment, the heating reaction time is 8 to 12 hours, for example, 8 hours, 9 hours, 10 hours, 11 hours or 12 hours.

[0023] In one embodiment, the heating reaction is followed by a drying process.

[0024] In one embodiment, the drying temperature is 80-110°C, for example, 80°C, 85°C, 90°C, 100°C or 110°C.

[0025] In one embodiment, the solvent of the phenyllithium solution in step (2) comprises diethyl ether.

[0026] In one embodiment, the concentration of phenyllithium in the phenyllithium-containing solution is 0.1 to 0.3 mol / L, for example, 0.1 mol / L, 0.15 mol / L, 0.2 mol / L, 0.25 mol / L or 0.3 mol / L.

[0027] In one embodiment, the solid-liquid ratio of the adsorbent precursor and the phenyllithium-containing solution is 1 to 2 g / mL, for example, 1 g / mL, 1.2 g / mL, 1.5 g / mL, 1.8 g / mL or 2 g / mL.

[0028] In one embodiment, the ultrasonic treatment time is 20 to 30 minutes, for example, 20 minutes, 22 minutes, 25 minutes, 28 minutes or 30 minutes.

[0029] In one embodiment, the solvent containing triphenylmethane solution in step (2) comprises diethyl ether.

[0030] In one embodiment, the molar ratio of phenyllithium in the phenyllithium-containing solution to triphenylmethane in the triphenylmethane-containing solution is 1:(2-3), for example, 1:2, 1:2.2, 1:2.5, 1:2.8 or 1:3.

[0031] In one embodiment, the reaction in step (2) comprises pre-stirring the reaction and then heating the reaction under reflux.

[0032] In one embodiment, the temperature of the pre-stirring reaction is 20-30°C, for example, 20°C, 22°C, 25°C, 28°C or 30°C.

[0033] In one embodiment, the pre-stirring reaction time is 1.5 to 3 hours, for example, 1.5 hours, 1.8 hours, 2 hours, 2.5 hours or 3 hours.

[0034] In one embodiment, the temperature of the heating reflux reaction is 60-80°C, for example, 60°C, 65°C, 70°C, 75°C or 80°C.

[0035] In one embodiment, the heating reflux reaction time is 0.5 to 2 hours, for example, 0.5 hours, 0.8 hours, 1 hour, 1.5 hours or 2 hours.

[0036] In one embodiment, the reaction is followed by washing with hot water.

[0037] In one embodiment, the mass fraction of tetraphenylmethane in the tetraphenylmethane-coated aluminum-based adsorbent in step (3) is 3-10%, for example, 3%, 5%, 6%, 8% or 10%.

[0038] In one embodiment, the gas for the plasma hydrophilic treatment in step (3) includes any one of ammonia, methane or oxygen or a combination of at least two thereof, and ammonia can be selected.

[0039] In one embodiment, the gas flow rate of the plasma hydrophilic treatment is 80 to 200 sccm, for example, 80 sccm, 100 sccm, 120 sccm, 150 sccm, or 200 sccm.

[0040] In one embodiment, the power of the plasma hydrophilic treatment is 100-300 W, for example, 100 W, 150 W, 200 W, 250 W or 300 W.

[0041] In one embodiment, the plasma hydrophilic treatment lasts for 30 to 300 seconds, for example, 30 seconds, 50 seconds, 100 seconds, 200 seconds, or 300 seconds.

[0042] In one embodiment, the gas pressure of the plasma hydrophilic treatment is 20-50 Pa, for example, 20 Pa, 25 Pa, 30 Pa, 40 Pa or 50 Pa.

[0043] In a second aspect, the present disclosure provides a modified lithium extraction adsorbent, which is prepared by the method described in the first aspect.

[0044] The outer modified layer of the modified lithium extraction adsorbent disclosed in the present invention can protect the inner adsorbent, isolate the inner adsorbent from the adsorption and desorption solution, and improve the cyclic stability of the adsorbent. The outer modified layer can also physically adsorb lithium ions in the brine, so it can protect the inner adsorbent without reducing the adsorption capacity.

[0045] In a third aspect, the present disclosure provides a method for extracting lithium, comprising the following steps:

[0046] (1) filling the modified lithium extraction adsorbent as described in the second aspect into a resin column, and immersing it in deionized water for activation treatment to obtain a desorbed adsorbent;

[0047] (2) After soaking the analyzed adsorbent in concentrated brine, the concentrated brine is replaced with ordinary brine for adsorption.

[0048] Since the adsorption capacity of the inner layer adsorbent and the outer modified layer of the modified lithium extraction adsorbent disclosed in the present invention is different, high-concentration brine adsorption is performed first and then low-concentration brine adsorption. The pore volume of the outer layer TPM after adsorbing lithium ions is more conducive to the passage of smaller chloride ions, which can slow down the sulfate poisoning phenomenon of the inner layer aluminum-based adsorbent.

[0049] In one embodiment, the lithium ion concentration in the concentrated brine is 500-1000 mg / L, for example, 500 mg / L, 600 mg / L, 800 mg / L, 900 mg / L or 1000 mg / L.

[0050] In one embodiment, the sulfate concentration in the concentrated brine is ≥8 g / L.

[0051] In one embodiment, the lithium ion concentration in the common brine is 100-300 mg / L, for example, 100 mg / L, 150 mg / L, 200 mg / L, 250 mg / L or 300 mg / L.

[0052] In one embodiment, the sulfate concentration in the common brine is 1 to 5 g / L, for example, 1 g / L, 2 g / L, 3 g / L, 4 g / L or 5 g / L.

[0053] Compared with the prior art, the present disclosure has the following beneficial effects:

[0054] (1) The present invention discloses a surface modified lithium extraction adsorbent. During the adsorption process of the adsorbent, lithium ions are attracted by the benzene rings on the surface and move to the high-energy binding site between the two benzene rings. After the benzene rings are saturated with adsorption, lithium ions can diffuse by filling the remaining pore space and diffuse into the internal adsorbent for lithium ion adsorption.

[0055] (2) The adsorption capacity of the modified lithium extraction adsorbent prepared by the method disclosed in the present invention can reach above 9.58 mg / g, and the capacity retention rate can reach above 95.83% after 100 cycles.

[0056] Still other aspects will become apparent upon reading and understanding the detailed description. DETAILED DESCRIPTION

[0057] 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.

[0058] Example 1

[0059] This embodiment provides a modified lithium extraction adsorbent, and the preparation method of the modified lithium extraction adsorbent is as follows:

[0060] (1) immersing activated alumina in a 20% by mass lithium chloride aqueous solution, controlling the molar ratio of alumina to lithium chloride to be 1:1.1, hydrothermally treating at 95°C for 10 hours, and then drying at 90°C to obtain a crystalline aluminum salt lithium ion adsorbent precursor;

[0061] (2) preparing a phenyllithium ether solution with a phenyllithium concentration of 0.2 mol / L, adding an aluminum salt adsorbent precursor to the above solution at a solid-liquid ratio of 1.5 g / mL and ultrasonicating for 30 minutes, then adding a 0.5 mol / L triphenylmethane ether solution to make a molar ratio of phenyllithium to triphenylmethane of 1:2.2, reacting at 25°C for 2 hours, and then heating under reflux at 70°C for 1 hour, filtering and washing the product with 50°C hot water to obtain a tetraphenylmethane-coated aluminum-based adsorbent;

[0062] (3) The aluminum-based adsorbent coated with tetraphenylmethane is placed in a low-temperature plasma generator, and the surface of the adsorbent is treated with ammonia plasma at a gas flow rate of 100 sccm, a power of 200 W, a time of 200 s, and a gas pressure of 30 Pa to obtain the modified lithium extraction adsorbent.

[0063] Example 2

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

[0065] (1) immersing activated alumina in a 15% by mass lithium chloride aqueous solution, controlling the molar ratio of alumina to lithium chloride to be 1:1, hydrothermally treating the solution at 90° C. for 12 h, and then drying the solution at 80° C. to obtain a crystalline aluminum salt lithium ion adsorbent precursor;

[0066] (2) preparing a phenyllithium ether solution with a phenyllithium concentration of 0.1 mol / L, adding an aluminum salt adsorbent precursor to the above solution at a solid-liquid ratio of 1 g / mL and ultrasonicating for 250 min, then adding a 0.5 mol / L triphenylmethane ether solution so that the molar ratio of phenyllithium to triphenylmethane is 1:2, reacting at 25°C for 1.5 h, then heating under reflux at 60°C for 2 h, filtering and washing the product with 50°C hot water to obtain a tetraphenylmethane-coated aluminum-based adsorbent;

[0067] (3) The aluminum-based adsorbent coated with tetraphenylmethane is placed in a low-temperature plasma generator, and the surface of the adsorbent is treated with ammonia plasma at a gas flow rate of 80 sccm, a power of 100 W, a time of 300 s, and a gas pressure of 20 Pa to obtain the modified lithium extraction adsorbent.

[0068] Example 3

[0069] This embodiment provides a modified lithium extraction adsorbent, and the preparation method of the modified lithium extraction adsorbent is as follows:

[0070] (1) immersing activated alumina in a 30% by mass lithium chloride aqueous solution, controlling the molar ratio of alumina to lithium chloride to be 1:1.2, hydrothermally treating the solution at 100° C. for 8 h, and then drying the solution at 110° C. to obtain a crystalline aluminum salt lithium ion adsorbent precursor;

[0071] (2) preparing a phenyllithium ether solution with a phenyllithium concentration of 0.3 mol / L, adding an aluminum salt adsorbent precursor to the above solution at a solid-liquid ratio of 2 g / mL and ultrasonicating for 30 minutes, then adding a 0.5 mol / L triphenylmethane ether solution to make a molar ratio of phenyllithium to triphenylmethane of 1:3, reacting at 25°C for 2 hours, and then heating under reflux at 80°C for 0.5 hours. After filtering, the product was washed with hot water at 50°C to obtain a tetraphenylmethane-coated aluminum-based adsorbent;

[0072] (3) The aluminum-based adsorbent coated with tetraphenylmethane is placed in a low-temperature plasma generator, and the surface of the adsorbent is treated with ammonia plasma at a gas flow rate of 200 sccm, a power of 300 W, a time of 30 s, and a gas pressure of 50 Pa to obtain the modified lithium extraction adsorbent.

[0073] Example 4

[0074] The only difference between this embodiment and embodiment 1 is that the molar ratio of phenyllithium to triphenylmethane is 1:1, and other conditions and parameters are exactly the same as those in embodiment 1.

[0075] Example 5

[0076] The only difference between this embodiment and embodiment 1 is that the molar ratio of phenyllithium to triphenylmethane is 1:4, and other conditions and parameters are exactly the same as those in embodiment 1.

[0077] Example 6

[0078] The only difference between this embodiment and embodiment 1 is that the power of the plasma hydrophilic treatment is 500 W, and the other conditions and parameters are exactly the same as those in embodiment 1.

[0079] Example 7

[0080] The only difference between this embodiment and embodiment 1 is that the power of the plasma hydrophilic treatment is 50 W, and the other conditions and parameters are exactly the same as those in embodiment 1.

[0081] Example 8

[0082] The only difference between this embodiment and embodiment 1 is that ammonia is replaced by oxygen, and other conditions and parameters are exactly the same as those in embodiment 1.

[0083] Example 9

[0084] The only difference between this embodiment and embodiment 1 is that ammonia is replaced by methane, and other conditions and parameters are exactly the same as those in embodiment 1.

[0085] Comparative Example 1

[0086] The only difference between this comparative example and Example 1 is that the crystalline aluminum salt lithium ion adsorbent precursor is directly used as the adsorbent, and the other conditions and parameters are exactly the same as those in Example 1.

[0087] Comparative Example 2

[0088] The only difference between this comparative example and Example 1 is that no phenyllithium solution is used, and other conditions and parameters are exactly the same as those in Example 1.

[0089] Comparative Example 3

[0090] The only difference between this comparative example and Example 1 is that the triphenylmethane-containing solution is not used, and the other conditions and parameters are exactly the same as those in Example 1.

[0091] Comparative Example 4

[0092] The only difference between this comparative example and Example 1 is that no plasma hydrophilic treatment is performed, and other conditions and parameters are exactly the same as those in Example 1.

[0093] Performance testing:

[0094] The adsorption performance test method is the static adsorption method. This adsorbent is used for Li + To extract lithium from brine with a concentration of 500 ppm, take 20 g of deionized water and mix it with 2 g of lithium adsorbent. Extract lithium at room temperature for 10 hours. Measure the brine concentration before and after adsorption, and calculate the adsorption capacity according to the following formula.

[0095] The adsorption capacity of the adsorbent is: Q = V (C0-C) / m;

[0096] 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.

[0097] 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:

[0098] Table 1

[0099] As can be seen from Table 1, from Examples 1-3, the adsorption capacity of the modified lithium extraction adsorbent prepared by the method of the present disclosure can reach above 9.58 mg / g, and the capacity retention rate after 100 cycles can reach above 95.83%.

[0100] By comparing Example 1 with Examples 4-5, it can be seen that in the preparation process of the modified lithium extraction adsorbent described in the present disclosure, the molar ratio of phenyllithium and triphenylmethane affects its performance. The molar ratio of phenyllithium and triphenylmethane is controlled at 1:2 to 3, and the performance of the modified lithium extraction adsorbent is better. If the proportion of phenyllithium is too large or too small, it is difficult to form tetraphenylmethane, which affects the performance of the adsorbent.

[0101] By comparing Example 1 with Examples 6-7, it can be seen that during the preparation process of the modified lithium extraction adsorbent disclosed in the present invention, the power of the plasma hydrophilic treatment will affect its performance. By controlling the power of the plasma hydrophilic treatment at 100-300W, the performance of the modified lithium extraction adsorbent is better. If the power of the plasma hydrophilic treatment is too large, the improvement of the hydrophilic effect is limited, and energy is wasted. If the power of the plasma hydrophilic treatment is too small, the hydrophilic improvement effect is poor, which affects the brine infiltration of the adsorbent.

[0102] From the comparison between Example 1 and Examples 8-9, it can be seen that in the preparation process of the modified lithium extraction adsorbent disclosed in the present invention, using ammonia as the atmosphere for plasma hydrophilic treatment has a better effect on the hydrophilic modification of the adsorbent.

[0103] By comparing Example 1 and Comparative Examples 1-3, it can be seen that the present disclosure uses phenyllithium and triphenylmethane to modify the crystalline aluminum salt lithium ion adsorbent. The benzene ring of the outer modified layer can attract lithium ions, improve the adsorption efficiency of lithium ions, and improve the lithium extraction efficiency. The tetramethylbenzene ring is an electron-donating group, which can attract the binder required for granulation during the granulation process, which is more conducive to the preparation of adsorbent particles with better cycle stability.

[0104] From the comparison between Example 1 and Comparative Example 4, it can be seen that plasma hydrophilic treatment can promote brine infiltration into the adsorbent and improve the adsorption capacity.

Claims

1. A preparation method of a modified lithium extraction adsorbent, comprising the following steps: (1) Mix activated alumina with a lithium salt solution and heat to react to obtain an adsorbent precursor; (2) Mix a phenyl lithium solution with the adsorbent precursor, after ultrasonic treatment, add a triphenylchloromethane solution, and react to obtain an aluminum-based adsorbent coated with tetraphenylmethane; (3) Perform plasma hydrophilic treatment on the aluminum-based adsorbent coated with tetraphenylmethane to obtain the modified lithium extraction adsorbent.

2. The preparation method according to claim 1, wherein, the solute of the lithium salt solution in step (1) comprises lithium chloride.

3. The preparation method according to claim 1 or 2, wherein, the solvent of the lithium salt solution comprises water.

4. The preparation method according to any one of claims 1-3, wherein, the mass concentration of the lithium salt solution is 15-30%.

5. The preparation method according to any one of claims 1-4, wherein, the molar ratio of activated alumina to lithium salt is 1:(1-1.2).

6. The preparation method according to any one of claims 1-5, wherein, the temperature of the heating reaction in step (1) is 90-100 °C; optionally, the time of the heating reaction is 8-12 h; optionally, drying treatment is performed after the heating reaction; optionally, the temperature of the drying treatment is 80-110 °C.

7. The preparation method according to any one of claims 1-6, wherein, the solvent of the phenyl lithium solution in step (2) comprises ether.

8. The preparation method according to any one of claims 1-7, wherein, the concentration of phenyl lithium in the phenyl lithium solution is 0.1-0.3 mol / L.

9. The preparation method according to any one of claims 1-8, wherein, the solid-liquid ratio of the adsorbent precursor to the phenyl lithium solution is 1-2 g / mL.

10. The preparation method according to any one of claims 1-9, wherein, the time of the ultrasonic treatment is 20-30 min.

11. The preparation method according to any one of claims 1-10, wherein, the solvent of the triphenylchloromethane solution in step (2) comprises ether; optionally, the molar ratio of phenyl lithium in the phenyl lithium solution to triphenylchloromethane in the triphenylchloromethane solution is 1:(2-3).

12. The preparation method according to any one of claims 1-11, wherein, the reaction in step (2) comprises a pre-stirring reaction followed by a heating reflux reaction; optionally, the temperature of the pre-stirring reaction is 20-30 °C; optionally, the time of the pre-stirring reaction is 1.5-3 h; optionally, the temperature of the heating reflux reaction is 60-80 °C; optionally, the time of the heating reflux reaction is 0.5-2 h; optionally, washing treatment is performed with hot water after the reaction.

13. The preparation method according to any one of claims 1-12, wherein, the mass fraction of tetraphenylmethane in the aluminum-based adsorbent coated with tetraphenylmethane in step (3) is 3-10%.

14. The preparation method according to any one of claims 1-13, wherein, The gas for the plasma hydrophilization treatment described in step (3) includes any one or a combination of at least two of ammonia, methane, or oxygen; Optionally, the gas flow rate for the plasma hydrophilization treatment is 80 - 200 sccm; Optionally, the power of the plasma hydrophilization treatment is 100 - 300 W; Optionally, the time of the plasma hydrophilization treatment is 30 - 300 s; Optionally, the air pressure of the plasma hydrophilization treatment is 20 - 50 Pa.

15. The preparation method according to any one of claims 1 - 14, wherein, the gas for the plasma hydrophilization treatment described in step (3) is ammonia.

16. A modified lithium extraction adsorbent prepared by the method according to any one of claims 1 - 15.

17. A lithium extraction method, comprising the following steps: (1) Filling the modified lithium extraction adsorbent according to claim 16 into a resin column, soaking and activating it in deionized water to obtain the resolved adsorbent; (2) After soaking the resolved adsorbent with concentrated brine, replacing the concentrated brine with ordinary brine for adsorption; Optionally, the lithium ion concentration in the concentrated brine is 500 - 1000 mg / L; Optionally, the sulfate ion concentration in the concentrated brine is ≥ 8 g / L; Optionally, the lithium ion concentration in the ordinary brine is 100 - 300 mg / L; Optionally, the sulfate ion concentration in the ordinary brine is 1 - 5 g / L.

Images