Aluminum-based lithium adsorbent and method for producing same

Abstract

This embodiment relates to an aluminum-based adsorbent with a sulfate group (SO4) as a counter ion, and specifically provides an aluminum-based lithium adsorbent represented by the chemical formula Li2SO4·4Al(OH)3·nH2O (n is 1 to 6) and a method for producing the same.

Description

[Technical Field]

[0001] The present embodiment relates to an aluminum-based lithium adsorbent having a sulfate group (SO) as a counter ion and a method for producing the same, and more specifically, to a method for producing an aluminum-based lithium adsorbent with improved durability that can efficiently separate lithium from a lithium sulfate solution. [Background technology]

[0002] In recent years, the rise of smart devices such as electric vehicles has led to a surge in demand for lithium batteries. As a result, the prices of lithium carbonate and lithium hydroxide, the materials used in lithium batteries, have skyrocketed, spurring research into extracting lithium, the main raw material for lithium carbonate and lithium hydroxide. Lithium can be extracted from salt lakes and ores using a variety of extraction methods, including natural evaporation, chemical methods, and direct lithium extraction. Various minerals are dissolved in lithium-containing salt lakes. The most common method for extracting lithium from salt lakes involves concentrating the brine using natural evaporation, removing residual calcium, magnesium, boron, and sulfate ions from the lithium-containing solution, and then adding sodium carbonate to extract lithium carbonate. While this method has the advantage of being inexpensive, it has the disadvantage of a low lithium recovery rate and a long processing time. To address these drawbacks, chemical methods, which use secondary materials to precipitate and remove impurities, and direct lithium extraction methods are available. Among these, the lithium extraction method uses an adsorbent, which has the advantage of not requiring additional secondary materials and allowing the adsorbent to be regenerated and reused. Research into various types of adsorbents, such as lithium manganese oxide (LMO), titanium, zirconium, and aluminum, is being actively conducted.

[0003] Among these, aluminum-based adsorbents with a double-plate structure have lithium counter ions between the stacked aluminum hydroxide plate structures, creating spaces through which water and counter ions can pass. The size of the voids in the aluminum hydroxide plate is similar to that of the lithium ions, allowing lithium to be adsorbed and desorbed in the voids, thereby enabling selective extraction of lithium. Therefore, depending on the type of counter ions located between the plate structures, it is possible to manufacture adsorbents that can extract lithium from various types of lithium solutions. In brine, the counter ions are Cl. - In most cases, the adsorbent is LiCl·2Al(OH)3·nH2O, and up until now, much research has been done on adsorbents in the form of LiCl·2Al(OH)3·nH2O. However, recently, various methods have been attempted to recover lithium from lithium sulfate solutions discharged from lithium battery recycling and lithium ore extraction. In other words, if an adsorbent is produced in the form of Li2SO4·4Al(OH)3·nH2O, the counter ion SO4 2- Lithium can be recovered from the lithium sulfate solution.

[0004] Chinese Patent Publication No. 112808226 discloses a method for producing an adsorbent in the form of Li2SO4·4Al(OH)3·nH2O by dissolving aluminum salt in water and adding sodium hydroxide to form an intermediate LiOH·2Al(OH)3·nH2O in an alkaline atmosphere, followed by a reaction with a sulfate-containing substance in an acidic atmosphere. This method involves a chemical reaction in a basic atmosphere to produce an intermediate, followed by a chemical reaction to form an acidic atmosphere and then a chemical reaction to produce the final adsorbent. The overall process for producing Li2SO4·4Al(OH)3·nH2O adsorbent is complex, requiring a large number of chemicals, which increases overall production costs and reduces process efficiency. The need for a variety of raw materials leads to a variety of downstream pollutant emissions and increases the burden of post-treatment processes for these pollutants. In addition, the specification of the above-mentioned Patent Application Publication No. 112808226 discloses that in order to improve the durability of the produced Li2SO4·4Al(OH)3·nH2O adsorbent, a coating layer is formed on the surface by additionally reacting with aluminate.

[0005] Therefore, there is a need to develop a lithium adsorbent that can efficiently extract lithium from a lithium sulfate solution using a simple process and has excellent durability. Summary of the Invention [Problem to be solved by the invention]

[0006] One embodiment of the present invention seeks to provide a method for producing an aluminum-based lithium adsorbent with improved durability that can efficiently recover lithium from lithium sulfate solutions. [Means for solving the problem]

[0007] An aluminum-based lithium adsorbent according to one embodiment of the present invention can be represented by Chemical Formula 1. [Chemical formula 1] Li2SO4·4Al(OH)3·nH2O (n is 1 to 6)

[0008] In XRD analysis of the aluminum-based lithium adsorbent, the intensities of the 2θ8°, 17°, 20°, and 26° peaks may be 10 or more, the intensity ratio of the 2θ44° peak to the 2θ20° peak may be in the range of 0.1 to 0.5, and the intensity ratio of the 2θ44° peak to the 2θ36° peak may be in the range of 0.3 to 0.7.

[0009] Furthermore, in XRD analysis, the intensity ratio of the 2θ44° peak to the 2θ8° peak may be in the range of 0.2 to 0.4, the intensity ratio of the 2θ44° peak to the 2θ17° peak may be in the range of 0.2 to 0.6, the intensity ratio of the 2θ17° peak to the 2θ36° peak may be in the range of 1.0 to 3.0, and the intensity ratio of the 2θ26° peak to the 2θ8° peak may be in the range of 0.3 to 0.7.

[0010] In addition, the flaky primary particles can be positioned at a predetermined angle on the surface.

[0011] A method for producing an aluminum-based lithium adsorbent according to one embodiment of the present invention includes the steps of: dissolving aluminum sulfate and lithium sulfate in distilled water to prepare a mixed aqueous solution; adding sodium hydroxide to the mixed aqueous solution to form a precipitate; aging the solution in which the precipitate has been formed to form a solid; and separating the solid. In the step of adding sodium hydroxide to the mixed aqueous solution to form a precipitate, a precipitate represented by Chemical Formula 1 can be formed. [Chemical formula 1] Li2SO4·4Al(OH)3·nH2O (n is 1 to 6) The step of adding sodium hydroxide to the mixed aqueous solution to form a precipitate may be carried out at a pH value in the range of about 7.0 to 11.0, and the sodium hydroxide may be added at a rate in the range of 0.05 mol / min to 1.0 mol / min.

[0012] In the step of dissolving aluminum sulfate and lithium sulfate in water to prepare a mixed aqueous solution, the aluminum sulfate and lithium sulfate may be mixed in a molar ratio range of 2:1 to 4:1, and the sodium hydroxide and aluminum sulfate may be mixed in a molar ratio range of 1.5:1 to 4:1.

[0013] The step of adding sodium hydroxide to the mixed aqueous solution to form a precipitate can form the precipitate through a reaction according to the following reaction formula 1. [Reaction Scheme 1] 2Al2(SO4)3·mH2O + Li2SO4 + 12NaOH → Li2SO4·4Al(OH)3·nH2O + 6Na2SO4 (where n is 1 to 6)

[0014] The method may further include a step of dissolving the aluminum sulfate and lithium sulfate in distilled water to prepare a mixed aqueous solution, and then heating the mixed aqueous solution at a temperature in the range of 70°C to 90°C.

[0015] The step of mixing sodium hydroxide into the mixed aqueous solution to form a precipitate can be carried out at a temperature in the range of 70°C to 100°C.

[0016] The step of aging the solution in which the precipitate is formed can be carried out at a temperature of 60° C. or higher for 1 hour to 24 hours.

[0017] After the step of separating the solids, the method may further include a step of washing the separated solids with water, and after washing the separated solids with water, the washed solids may be dried at a temperature in the range of 40°C to 60°C for 24 to 48 hours. [Effects of the Invention]

[0018] According to one embodiment of the present invention, it is possible to efficiently extract lithium from a lithium sulfate solution and to prepare an aluminum-based lithium adsorbent having improved durability. In addition, the overall process is simple, the types of raw materials used are minimized, and the overall process efficiency is improved, which is environmentally friendly. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a diagram schematically illustrating a method for producing an aluminum-based lithium adsorbent according to one embodiment of the present invention. [Figure 2] FIG. 1 is a diagram showing the results of XRD analysis of aluminum-based lithium adsorbents according to Examples 1 to 3 of the present invention. [Figure 3] FIG. 2 is a diagram showing the results of XRD analysis of aluminum-based lithium adsorbents according to Examples 3 and 4 of the present invention and Comparative Example 1. [Figure 4] FIG. 2 is a diagram showing SEM images of adsorbents according to Examples 3 and 4 of the present invention and Comparative Example 1. [Figure 5] FIG. 1 shows SEM images of adsorbents according to Comparative Examples 2 and 3. [Figure 6] FIG. 10 shows the results of XRD analysis of the solid produced after aging in Example 3 before and after washing with fresh water. DETAILED DESCRIPTION OF THE INVENTION

[0020] In describing the present invention, terms such as first, second, and third are used to describe various parts, components, regions, layers, and / or sections, but are not limited to these. These terms are used only to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Therefore, a first part, component, region, layer, or section described below can be referred to as a second part, component, region, layer, or section without departing from the scope of the present invention.

[0021] The terminology used herein is for the purpose of referring to particular embodiments only and is not intended to limit the present invention. As used herein, the singular forms "a," "an," and "the" include the plural forms unless the context clearly dictates otherwise. As used herein, the term "comprising" refers to the inclusion of specific features, regions, integers, steps, operations, elements, and / or components, and does not exclude the presence or addition of other features, regions, integers, steps, operations, elements, and / or components.

[0022] Unless otherwise defined, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by a person of ordinary skill in the art to which the present invention pertains. Terms defined in commonly used dictionaries are additionally interpreted to have a meaning consistent with the relevant technical literature and the presently disclosed content, and are not interpreted as having an ideal or very formal meaning unless defined.

[0023] DETAILED DESCRIPTION OF THE INVENTION The following detailed description of the preferred embodiments of the present invention is provided by way of example only and is not intended to limit the scope of the present invention, which is defined solely by the claims set forth below.

[0024] FIG. 1 is a diagram schematically illustrating a method for producing an aluminum-based lithium adsorbent according to one embodiment of the present invention. Referring to Figure 1, a step of preparing a mixed aqueous solution can be performed by dissolving aluminum sulfate and lithium sulfate in distilled water. The aluminum sulfate and lithium sulfate can be mixed in a molar ratio of 2:1 to 4:1, specifically, 2.5:1 to 3.5:1. When the molar ratio of aluminum sulfate and lithium sulfate satisfies this range, it is advantageous for effectively preparing the aluminum-based lithium adsorbent represented by Chemical Formula 1, which is the objective of the present invention. [Chemical formula 1] Li2SO4·4Al(OH)3·nH2O (n is 1 to 6)

[0025] The prepared mixed aqueous solution of aluminum sulfate and lithium sulfate can be heated at a temperature in the range of 70°C to 90°C, specifically, at a temperature in the range of 80°C to 90°C.

[0026] Next, a step of adding sodium hydroxide to the prepared mixed aqueous solution can be performed. Specifically, sodium hydroxide can be added to the mixed aqueous solution at a predetermined rate to form a precipitate. At this time, the total amount of sodium hydroxide added can be in a range of 1.5:1 to 4:1 based on the molar ratio of aluminum sulfate, specifically, in a range of 2:1 to 4:1. Mixing sodium hydroxide and aluminum sulfate in this range effectively forms aluminum hydroxide, which is advantageous for improving the quality of the final aluminum-based lithium adsorbent.

[0027] Meanwhile, the sodium hydroxide can be added to the aluminum sulfate and lithium sulfate mixed aqueous solution at a rate of 0.05 mol / min to 1.0 mol / min, specifically 0.1 mol / min to 0.5 mol / min. Adding sodium hydroxide at this rate prevents the particle size of the product from becoming too small, which is advantageous for the effective progress of the subsequent separation step.

[0028] The step of adding sodium hydroxide to the prepared mixed aqueous solution can be carried out under conditions of a pH value in the range of 7 to 11. If the pH value is below this range, it is difficult to produce an adsorbent having the structure targeted in the present invention, while if the pH value is above this range, the structure of the final material produced is destroyed, making it difficult for the material to function as an adsorbent.

[0029] Alternatively, the reaction may be carried out at a temperature of 100° C. or lower, specifically at a temperature in the range of 70° C. to 100° C., and the sodium hydroxide may be added while stirring the mixed aqueous solution at a speed in the range of 200 rpm to 1000 rpm. Stirring in this manner is advantageous in that the added sodium hydroxide rapidly diffuses into the mixed aqueous solution and effectively forms a precipitate.

[0030] At this time, a precipitate can be formed by a reaction according to the following reaction formula 1. [Reaction Scheme 1] 2Al2(SO4)3·mH2O + Li2SO4 + 12NaOH → Li2SO4·4Al(OH)3·nH2O + 6Na2SO4 (where n is 1 to 6)

[0031] Subsequently, after adding sodium hydroxide to the prepared mixed aqueous solution, the solution in which a precipitate is formed may be aged at a temperature of 60° C. or higher for 1 hour to 24 hours.

[0032] After aging, the mixture can be filtered to separate the solid and liquid. The separated solid can be washed with water to remove surface impurities. This washing can be done with fresh water or distilled water.

[0033] The washed solid material can be dried for 24 to 48 hours at a temperature ranging from 40 to 60° C. When the drying temperature is within this range, the drying time is not too long and it is advantageous in preventing the problem of the structure being destroyed at high temperatures, resulting in a decrease in adsorption performance.

[0034] In another embodiment of the present invention, an aluminum-based lithium adsorbent prepared by the above method can be provided. The aluminum-based lithium adsorbent is represented by the following Chemical Formula 1: [Chemical formula 1] Li2SO4·4Al(OH)3·nH2O (n is 1 to 6)

[0035] The aluminum-based lithium adsorbent is formed by solidifying flaky crystals that form voids. Meanwhile, XRD analysis of the aluminum-based lithium adsorbent shows peaks with 2θ angles of 8°, 17°, 20°, 26°, 36°, 38°, and 44°. In the XRD analysis herein, the value of the diffraction angle 2θ may be in the range of ±1.0°, specifically, ±0.50°.

[0036] Meanwhile, in an XRD analysis, the intensity ratio of the 2θ44° peak to the 2θ20° peak (I44° / I20°) may be in the range of 0.1 to 0.5, specifically 0.2 to 0.4.

[0037] In XRD analysis, the intensity ratio of the 2θ44° peak to the 2θ36° peak (I44° / I36°) may be in the range of 0.3 to 0.7, specifically 0.4 to 0.6, the intensity ratio of the 2θ44° peak to the 2θ17° peak (I44° / I17°) may be in the range of 0.2 to 0.6, specifically 0.3 to 0.5, and the intensity ratio of the 2θ44° peak to the 2θ8° peak (I44° / I8°) may be in the range of 0.2 to 0.4, specifically 0.25 to 0.35.

[0038] In XRD analysis, the intensity ratio of the 2θ17° peak to the 2θ36° peak (I17° / I36°) may be in the range of 1.0 to 3.0, specifically 1.0 to 2.5, and the intensity ratio of the 2θ26° peak to the 2θ8° peak (I26° / I8°) may be in the range of 0.3 to 0.7, specifically 0.4 to 0.6. [Example]

[0039] The following detailed description of the present invention is provided by way of example only, and is not intended to limit the scope of the present invention, which is defined solely by the claims set forth below.

[0040] (Examples 1 to 3) First, 7 L of water was added to a 10 L double-jacket reactor and heated to 50°C. 1.49 kg of Al2(SO4)3·mH2O (m = 14-18) and 0.14 kg of Li2SO4 were added. The mixture was stirred at 200 rpm for 30 minutes until the mixture was completely dissolved. The temperature of the mixture was then increased to 70°C, 80°C, and 90°C. After the temperature was increased to these temperatures, 1.14 kg of 50 wt% NaOH was added over a 1-hour period. The pH of the solution was adjusted to approximately 7. The solution temperature was kept below 100°C, and after the reaction was complete, the mixture was aged at 60°C or higher for 1-16 hours. After aging, the resulting solid was filtered and washed twice with fresh water (1 L). The solid matter washed with fresh water was filtered and dried in an oven at 45°C for 24 hours to finally produce 0.5 kg of aluminum-based lithium adsorbent. At this time, the production yield of the aluminum-based lithium adsorbent was confirmed to be about 90%.

[0041] Example 4 An aluminum-based lithium adsorbent was prepared in the same manner as in Example 3, except that the temperature of the mixed aqueous solution was 90° C. and the pH was 11.07.

[0042] (Comparative Example 1) An aluminum-based lithium adsorbent was prepared in the same manner as in Example 4, except that the pH was adjusted to 12.82.

[0043] (Comparative Example 2) An aluminum-based lithium adsorbent was prepared in the same manner as in Example 1, except that LiOH was used instead of Li2SO4.

[0044] (Comparative Example 3) An aluminum-based lithium adsorbent was prepared in the same manner as in Example 1, except that NaOH was added all at once to the mixed aqueous solution of Al2(SO4)3·mH2O and Li2SO4.

[0045] FIG. 2 is a diagram showing the results of XRD analysis of the aluminum-based lithium adsorbents according to Examples 1 to 3 of the present invention. 2, the XRD analysis results for the aluminum-based lithium adsorbents according to Examples 1 to 3 of the present invention show that the typical peaks of LiSO·4Al(OH)·nH2O at 2θ of 8°, 17°, 20°, 26°, 36°, 38°, and 44° are clearly formed. This indicates that the aluminum-based lithium adsorbents with excellent crystallinity were prepared.

[0046] FIG. 3 is a diagram showing the results of XRD analysis of the aluminum-based lithium adsorbents according to Examples 3 and 4 of the present invention and Comparative Example 1. Referring to FIG. 3, in the case of the aluminum-based lithium adsorbents according to Examples 3 and 4 of the present invention, the representative peak of LiSO·4Al(OH)·nHO is clearly formed, confirming that an adsorbent with excellent crystallinity was prepared.

[0047] On the other hand, in the case of Comparative Example 1, the typical 2θ44° peak of LiSO4·4Al(OH)3·nH2O disappeared, and the 2θ26° peak shifted to the left. It was also shown that peaks other than the typical peak of LiSO4·4Al(OH)3·nH2O were formed. This confirms that the crystalline structure of the adsorbent of Comparative Example 2 had changed.

[0048] Furthermore, from the SEM analysis results of the aluminum-based lithium adsorbents according to Examples 3 and 4 and Comparative Example 1 in Fig. 4, it can be seen that the adsorbents according to Examples 3 and 4 have a well-formed crystalline phase. It can also be seen that the adsorbents are in the form of aggregated flaky primary particles, and that the broad faces of the flaky primary particles are positioned at a predetermined angle with the surface of the adsorbent. On the other hand, the adsorbent according to Comparative Example 1 was shown to have a shape in which the particles were fused and aggregated.

[0049] Fig. 5 shows SEM images of the adsorbents according to Comparative Examples 2 and 3. Fig. 5(a) shows an SEM image of the adsorbent according to Comparative Example 2, and Fig. 5(b) shows an SEM image of the adsorbent according to Comparative Example 3. Referring to Figure 5, it can be seen that nano-sized particles were formed when NaOH was added all at once (Figure 5(b)), while micro-sized particles were formed when NaOH was added in stages (Figure 5(a)). Also, referring to Figure 5(a), it was observed that flaky primary particles aggregated to form micro-sized particles, and the broad surfaces of the flaky primary particles wrapped around the surfaces to form micro-sized particles.

[0050] FIG. 6 shows the XRD analysis results of the solid matter produced after aging in Example 3, which was separated by filtration, before and after washing with fresh water. Referring to Figure 6, it can be seen that after fresh water washing, the Na2SO4 peak remaining on the surface disappeared and the typical peak of Li2SO4·4Al(OH)3·nH2O became more clearly visible. Therefore, it can be seen that the purity of the aluminum-based lithium adsorbent produced by fresh water washing was improved.

[0051] (Experimental example) Using the aluminum-based lithium adsorbent prepared in Example 3 of the present invention, lithium adsorption and desorption experiments were carried out in a lithium sulfate solution.

[0052] First, lithium sulfate solutions were prepared in which lithium sulfate was dissolved at concentrations of 970 ppm and 510 ppm, respectively. For the adsorption experiment, 100 mL of lithium sulfate solution with lithium concentrations of 1000 ppm and 500 ppm was prepared, and 10 g of adsorbent was added to each solution, followed by stirring for 24 hours to allow adsorption. The solution was then added again to 100 mL of fresh water and stirred for 24 hours to allow desorption, and the lithium concentration of each solution was measured by ICP to calculate the adsorption and desorption rates. The experimental results are summarized in Table 1 below.

[0053] [Table 1]

[0054] Referring to Table 1, when the aluminum-based lithium adsorbent prepared according to the present invention was used, the lithium adsorption rate in the lithium sulfate solution was confirmed to be about 12% to 20%, and the desorption rate was confirmed to be 90% or more.

[0055] The present invention is not limited to the above-described embodiments, and can be manufactured in various different forms, and those skilled in the art will understand that the present invention can be embodied in other specific forms without changing the technical spirit or essential features of the present invention. Therefore, the above-described embodiments should be understood to be illustrative in all respects and not limiting.

Claims

1. XRD analysis showed peaks at 2θ 8°, 17°, 20° and 26°. Represented by the following chemical formula 1: Aluminum-based lithium adsorbent. [Chemical formula 1] Li ２ SO ４ ・40l(OH) ３ ・nH ２ O(nは1~6)

2. In the XRD analysis, the intensity ratio of the 2θ 44° peak to the 2θ 20° peak is in the range of 0.1 to 0.

5. The aluminum-based lithium adsorbent according to claim 1.

3. In the XRD analysis, the intensity ratio of the 2θ 44° peak to the 2θ 36° peak is in the range of 0.3 to 0.

7. The aluminum-based lithium adsorbent according to claim 1.

4. In the XRD analysis, the intensity ratio of the 2θ 17° peak to the 2θ 36° peak is in the range of 1.0 to 3.

0. The aluminum-based lithium adsorbent according to claim 1.

5. In the XRD analysis, the intensity ratio of the 2θ 44° peak to the 2θ 8° peak is in the range of 0.2 to 0.

4. The aluminum-based lithium adsorbent according to claim 1.

6. In the XRD analysis, the intensity ratio of the 2θ 44° peak to the 2θ 17° peak is in the range of 0.2 to 0.

6. The aluminum-based lithium adsorbent according to claim 1.

7. In the XRD analysis, the intensity ratio of the 2θ26° peak to the 2θ8° peak is in the range of 0.3 to 0.

7. The aluminum-based lithium adsorbent according to claim 1.

8. The aluminum-based lithium adsorbent is The flaky primary particles are positioned at a predetermined angle on the surface. The aluminum-based lithium adsorbent according to claim 1.

9. Dissolving aluminum sulfate and lithium sulfate in distilled water to prepare a mixed aqueous solution; adding sodium hydroxide to the mixed aqueous solution to form a precipitate; Aging the solution in which the precipitate has formed to form a solid; and separating the solids; In the step of adding sodium hydroxide to the mixed aqueous solution to form a precipitate, a precipitate represented by Chemical Formula 1 is formed. A method for producing an aluminum-based lithium adsorbent. [Chemical formula 1] Li ２ SO ４ ・40l(OH) ３ ・nH ２ O(nは1~6)

10. The step of adding sodium hydroxide to the mixed aqueous solution to form a precipitate includes: The pH value is in the range of about 7.0 to 11.

0. The method for producing the aluminum-based lithium adsorbent according to claim 9.

11. The step of adding sodium hydroxide to the mixed aqueous solution to form a precipitate includes: The sodium hydroxide is added at a rate ranging from 0.05 mol / min to 1.0 mol / min. The method for producing the aluminum-based lithium adsorbent according to claim 9.

12. The step of dissolving aluminum sulfate and lithium sulfate in water to prepare a mixed aqueous solution includes: The aluminum sulfate and lithium sulfate are mixed in a molar ratio of 2:1 to 4:

1. The method for producing the aluminum-based lithium adsorbent according to claim 9.

13. The step of adding sodium hydroxide to the mixed aqueous solution to form a precipitate includes: The sodium hydroxide and aluminum sulfate are mixed in a molar ratio of 1.5:1 to 4:

1. The method for producing the aluminum-based lithium adsorbent according to claim 9.

14. The step of adding sodium hydroxide to the mixed aqueous solution to form a precipitate includes: forming a precipitate by a reaction according to Reaction Scheme 1 below: The method for producing the aluminum-based lithium adsorbent according to claim 9. [Reaction Scheme 1] 2Al ２ (SOO) ４ ) ３ ・mH ２ O+L ２ SO ４ +12NaOH→Li ２ SO ４ ・4Al(OH) ３ nH ２ O+6N ２ SO ４ (where n is 1 to 6)

15. The aluminum sulfate and lithium sulfate are dissolved in distilled water to prepare a mixed aqueous solution, and then further comprising the step of heating the mixed aqueous solution at a temperature in the range of 70°C to 90°C; The method for producing the aluminum-based lithium adsorbent according to claim 9.

16. The step of mixing sodium hydroxide into the mixed aqueous solution to form a precipitate includes: At a temperature ranging from 70°C to 100°C, The method for producing the aluminum-based lithium adsorbent according to claim 9.

17. The step of aging the solution in which the precipitate is formed is carried out at a temperature of 60°C or higher for 1 hour to 24 hours. The method for producing the aluminum-based lithium adsorbent according to claim 9.

18. After the solids separation step, further comprising the step of washing the separated solids with water. The method for producing the aluminum-based lithium adsorbent according to claim 9.

19. After washing the separated solid with water, further comprising the step of drying the washed solids at a temperature ranging from 40°C to 60°C for a period of 24 to 48 hours. The method for producing the aluminum-based lithium adsorbent according to claim 18.

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