Aluminum lithium adsorbent and preparation method thereof

Abstract

The present embodiment relates to an aluminum-based adsorbent having a sulfate group (SO4) as a counterion, and more specifically, to an aluminum-based lithium adsorbent having a chemical formula represented by Li2SO4. 4Al (OH) 3. NH2O (n is 1 to 6) and a method for preparing the same.

Description

Technical Field

[0001] This embodiment relates to an aluminum-based lithium adsorbent having sulfate (SO4) as a counter ion and a preparation method thereof. Specifically, it relates to a preparation method of an aluminum-based lithium adsorbent with improved durability that can efficiently separate lithium in a lithium sulfate solution. Background Art

[0002] Recently, due to the popularization of intelligent devices such as electric vehicles, the demand for lithium batteries has increased sharply. Therefore, the prices of lithium carbonate and lithium hydroxide, which are materials for lithium batteries, have risen significantly recently, and research on lithium, the main raw material for extracting lithium carbonate and lithium hydroxide, has also become active. Lithium can be mainly extracted from salt lakes and ores, and there are various extraction methods, including natural evaporation method, chemical method, direct lithium extraction method, etc. In the lithium-containing salt lake, various minerals are dissolved. The conventional method for extracting lithium from the salt lake is to concentrate the brine by the natural evaporation method, while removing residual calcium, magnesium, boron, sulfate ions, etc. in the lithium-containing solution, and then adding sodium carbonate to extract lithium carbonate. The advantage of this method is low cost, but the disadvantages are low lithium recovery rate and long time consumption. To make up for these disadvantages, there are chemical methods of using auxiliary raw materials for precipitation and removing impurities and direct lithium extraction methods. Among them, the lithium extraction method using an adsorbent has the advantages of not using additional auxiliary raw materials and being able to be reused by regenerating the adsorbent. Therefore, research on various forms of adsorbents such as lithium manganese oxide (LMO)-based, titanium-based, zirconium-based, and aluminum-based is being actively carried out.

[0003] Among them, the aluminum-based adsorbent with a double-layer plate structure has a lithium counter ion between the stacked aluminum hydroxide plate structures, thus forming a space through which water or counter ions can pass, and the pore size existing in the aluminum hydroxide plate is similar to that of lithium ions. Therefore, lithium can be adsorbed and desorbed through the pores, thereby selectively extracting lithium. Therefore, according to the type of counter ion located between the plate structures, an adsorbent capable of extracting lithium in various types of lithium solutions can be prepared. The counter ion in the brine is mostly Cl-. So far, adsorbents in the form of LiCl·2Al(OH)3·nH2O have been widely studied. However, recently, in the processes of lithium battery recycling or lithium extraction from ores, attempts have been made to recover lithium from the discharged lithium sulfate solution by various methods. That is, by preparing an adsorbent in the form of Li2SO4·4Al(OH)3·nH2O, lithium can be recovered from a lithium sulfate solution with SO4 as the counter ion in the same mechanism as extracting lithium in a lithium chloride solution. 2- as the counter ion.

[0004] In Chinese Patent CN2020-11504630, a method is proposed, that is, dissolving aluminum salt in water, adding sodium hydroxide, forming an intermediate of LiOH·2Al(OH)3·nH2O in an alkaline environment, and then reacting with a sulfate-containing substance in an acidic environment to prepare an adsorbent in the form of Li2SO4·4Al(OH)3·nH2O. The preparation method involves carrying out chemical reactions in an alkaline environment to prepare the intermediate, then adding compounds again to form an acidic environment, and finally preparing the final adsorbent through chemical reactions. The entire process for preparing the Li2SO4·4Al(OH)3·nH2O adsorbent is complex, and a large variety of chemical substances are used, which not only leads to an increase in the overall production cost and a decrease in process efficiency, but also due to the diversity of raw materials, results in the diversity of downstream pollutant emissions and an increase in the post-treatment process load of the discharged pollutants. In addition, Patent CN2020-11504630 also discloses that in order to improve the durability of the prepared Li2SO4·4Al(OH)3·nH2O adsorbent, a coating is formed on its surface by further reacting with an aluminum oxide salt.

[0005] Therefore, there is a need to develop a lithium adsorbent that can effectively extract lithium from a lithium sulfate solution through a simple process and has excellent durability. Summary of the Invention

[0006] Technical Problem

[0007] In one embodiment of the present invention, an object is to provide a method for preparing an aluminum-based lithium adsorbent with improved durability, which can effectively recover lithium from a lithium sulfate solution.

[0008] Technical Solution

[0009] The aluminum-based lithium adsorbent according to an embodiment of the present invention is represented by Chemical Formula 1 below.

[0010] [Chemical Formula 1]

[0011] Li2SO4·4Al(OH)3·nH2O (n is from 1 to 6)

[0012] In the XRD analysis of the aluminum-based lithium adsorbent, the peak intensities at 2θ of 8°, 17°, 20° and 26° are 10 or more. The intensity ratio of the peak at 2θ of 44° to the peak at 2θ of 20° is in the range of 0.1 to 0.5, and the intensity ratio of the peak at 2θ of 44° to the peak at 2θ of 36° is in the range of 0.3 to 0.7.

[0013] In addition, in the XRD analysis, the intensity ratio of the peak at 2θ = 44° to the peak at 2θ = 8° is in the range of 0.2 to 0.4, and the intensity ratio of the peak at 2θ = 44° to the peak at 2θ = 17° is in the range of 0.2 to 0.6. In the XRD analysis, the intensity ratio of the peak at 2θ = 17° to the peak at 2θ = 36° is in the range of 1.0 to 3.0, and the intensity ratio of the peak at 2θ = 26° to the peak at 2θ = 8° is in the range of 0.3 to 0.7.

[0014] Moreover, the plate-like primary particles are located on the surface at a certain angle.

[0015] The method for preparing an aluminum-based lithium adsorbent according to an embodiment of the present invention includes: a step of dissolving aluminum sulfate and lithium sulfate in distilled water to prepare a mixed aqueous solution; a step of adding sodium hydroxide to the mixed aqueous solution to form a precipitate; a step of aging the solution forming the precipitate to form a solid; and a step of separating the solid; wherein, 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.

[0016] [Chemical Formula 1]

[0017] Li2SO4·4Al(OH)3·nH2O (n is 1 to 6)

[0018] The step of adding sodium hydroxide to the mixed aqueous solution to form a precipitate is carried out in the range of a pH value of about 7.0 to 11.0, and sodium hydroxide is added at a rate of 0.05 mol / min to 1.0 mol / min.

[0019] In the step of dissolving aluminum sulfate and lithium sulfate in distilled water to prepare a mixed aqueous solution, aluminum sulfate and lithium sulfate are mixed at a molar ratio in the range of 2:1 to 4:1. In the step of adding sodium hydroxide to the mixed aqueous solution to form a precipitate, sodium hydroxide and aluminum sulfate are mixed at a molar ratio in the range of 1.5:1 to 4:1.

[0020] In the step of adding sodium hydroxide to the mixed aqueous solution to form a precipitate, a precipitate is formed through the reaction of Reaction Formula 1 below.

[0021] [Reaction Formula 1]

[0022] 2Al2(SO4)3·mH2O + Li2SO4 + 12NaOH → Li2SO4·4Al(OH)3·nH2O + 6Na2SO4

[0023] (Here, n is 1 to 6)

[0024] After dissolving aluminum sulfate and lithium sulfate in distilled water to prepare a mixed aqueous solution, it further includes the step of heating the mixed aqueous solution to 70°C to 90°C.

[0025] The step of adding sodium hydroxide to the mixed aqueous solution to form a precipitate is carried out at a temperature in the range of 70°C to 100°C.

[0026] The step of aging the solution in which the precipitate is formed can be carried out at a temperature above 60°C for 1 hour to 24 hours.

[0027] After the step of separating the solid matter, it may further include the step of washing the separated solid matter with water. After washing the separated solid matter with water, it includes the step of drying the washed solid matter at a temperature in the range of 40°C to 60°C for 24 to 48 hours.

[0028] Advantages of the Invention

[0029] According to an embodiment of the present invention, lithium can be effectively extracted from a lithium sulfate solution, and an aluminum-based lithium adsorbent with improved durability can be prepared.

[0030] In addition, the entire process is simple, and by minimizing the types of raw materials used, the overall process efficiency is improved, and it has the advantage of environmental protection. Brief Description of the Drawings

[0031] Figure 1 Generally shows the preparation method of the aluminum-based lithium adsorbent in the embodiment of the present invention.

[0032] Figure 2 Shows the XRD analysis results of the aluminum-based lithium adsorbents according to Embodiments 1 to 3 of the present invention.

[0033] Figure 3 Shows the XRD analysis results of the aluminum-based lithium adsorbents according to Embodiments 3 to 4 and Comparative Example 1 of the present invention.

[0034] Figure 4 Shows the SEM images of the adsorbents according to Embodiments 3 to 4 and Comparative Example 1 of the present invention.

[0035] Figure 5 Shows the SEM images of the adsorbents according to Comparative Example 2 and Comparative Example 3.

[0036] Figure 6 Shows the XRD analysis results of the solid generated after aging in Example 3 before and after washing with fresh water. Detailed Description of the Embodiments

[0037] In the description of the present invention, terms such as first, second, third, etc. are used to describe multiple parts, components, regions, layers, and / or segments, but these parts, components, regions, layers, and / or segments should not be limited by these terms. These terms are only used to distinguish one part, component, region, layer, and / or segment from another part, component, region, layer, and / or segment. Therefore, without departing from the scope of the present invention, the first part, component, region, layer, and / or segment described below can also be described as the second part, component, region, layer, and / or segment.

[0038] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. Unless otherwise clearly indicated to the contrary in the context, the singular forms used are also intended to include the plural forms. It should also be understood that the term "comprising" used in the specification may specifically refer to a certain characteristic, field, integer, step, action, element, and / or component, but does not exclude the existence or addition of other characteristics, fields, integers, steps, actions, elements, and / or components.

[0039] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. For terms defined in a dictionary, they should be interpreted as having a meaning consistent with the relevant technical literature and the content disclosed herein, and should not be interpreted in an idealized or overly formal sense.

[0040] Embodiments of the present invention will be described in detail below. However, this is only provided as an example, and the present invention is not limited thereto, and the present invention is only defined by the scope of the following claims.

[0041] Figure 1 Generally shows the preparation method of the aluminum-based lithium adsorbent in the embodiments of the present invention.

[0042] Reference Figure 1 , first, a step of dissolving aluminum sulfate and lithium sulfate in distilled water to prepare a mixed aqueous solution is carried out. The aluminum sulfate and lithium sulfate can be mixed in a molar ratio range of 2:1 to 4:1. Specifically, they can be mixed in a ratio range of 2.5:1 to 3.5:1. When the molar ratio of aluminum sulfate to lithium sulfate satisfies the above range, it is beneficial to effectively prepare the aluminum-based lithium adsorbent shown by Chemical Formula 1 of the present invention.

[0043] [Chemical Formula 1]

[0044] Li2SO4·4Al(OH)3·nH2O (n is 1 to 6)

[0045] The prepared mixed aqueous solution of aluminum sulfate and lithium sulfate can be heated to a temperature range of 70°C to 90°C. Specifically, it can be heated to a temperature range of 80°C to 90°C.

[0046] Next, the step of adding sodium hydroxide to the prepared mixed aqueous solution can be carried out. Specifically, sodium hydroxide can be added to the mixed aqueous solution at a certain rate to form a precipitate. At this time, the total amount of sodium hydroxide added can be mixed in the range of 1.5:1 to 4:1 based on the molar basis of the aluminum sulfate, specifically, it can be mixed in the ratio range of 2:1 to 4:1. When sodium hydroxide and aluminum sulfate are mixed in the above range, aluminum hydroxide can be effectively generated, which is beneficial to improving the quality of the final product, the aluminum-based lithium adsorbent.

[0047] On the other hand, the sodium hydroxide can be added to the mixed aqueous solution of aluminum sulfate and lithium sulfate 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 in this rate range can prevent the particle size of the product from being too small, which is beneficial to the effective progress of the subsequent separation process.

[0048] The step of adding sodium hydroxide to the prepared mixed aqueous solution can be carried out under the condition that the pH value is 7 to 11. When the pH value is lower than the above range, there will be a problem that it is difficult to produce an adsorbent with the target structure of the present invention; while when the pH value is higher than the above range, the structure of the finally generated substance will be damaged, and it is difficult to perform the function as an adsorbent.

[0049] In addition, it can be carried out at a temperature below 100 °C. Specifically, it can be carried out in the range of 70 °C to 100 °C, and sodium hydroxide can be added while stirring the mixed aqueous solution at a speed in the range of 200 rpm to 1000 rpm. When stirring in this way, the added sodium hydroxide can quickly diffuse into the interior of the mixed aqueous solution, which is beneficial to the effective formation of a precipitate.

[0050] At this time, a precipitate can be formed through the reaction of Reaction Formula 1 below.

[0051] [Reaction Formula 1]

[0052] 2Al2(SO4)3·mH2O + Li2SO4 + 12NaOH → Li2SO4·4Al(OH)3·nH2O + 6Na2SO4

[0053] Here, n is from 1 to 6.

[0054] Then, after adding sodium hydroxide completely to the prepared mixed aqueous solution, the solution forming the precipitate can be aged for 1 to 24 hours at a temperature above 60 °C.

[0055] After completing the aging, the solid can be separated by filtration. The separated solid can be washed with water to remove surface impurities. At this time, fresh water or distilled water can be used for washing.

[0056] The washed solid can be dried at a temperature in the range of 40°C to 60°C within 24 hours to 48 hours. When the drying temperature is within the said range, it is possible to avoid too long drying time and prevent the problem of reduced adsorption performance caused by the destruction of the structure at high temperature.

[0057] In another embodiment of the present invention, an aluminum-based lithium adsorbent prepared according to the said method can be provided. The aluminum-based lithium adsorbent is represented by the following Chemical Formula 1.

[0058] [Chemical Formula 1]

[0059] Li2SO4·4Al(OH)3·nH2O (n is from 1 to 6)

[0060] The aluminum-based lithium adsorbent can be formed by the aggregation of flaky crystals to form pores.

[0061] On the other hand, in the XRD analysis of the aluminum-based lithium adsorbent, peaks at 2θ of 8°, 17°, 20°, 26°, 36°, 38° and 44° can appear. In this specification, the numerical range of the diffraction angle 2θ in the XRD analysis can be ±1.0°, specifically, it can be in the range of ±0.50°.

[0062] On the other hand, in the XRD analysis, the intensity ratio (I44° / I20°) of the peak at 2θ of 44° to the peak at 2θ of 20° can be in the range of 0.1 to 0.5, specifically in the range of 0.2 to 0.4.

[0063] In addition, in the XRD analysis, the intensity ratio (I44° / I36°) of the peak at 2θ of 44° to the peak at 2θ of 36° can be in the range of 0.3 to 0.7, specifically it can be in the range of 0.4 to 0.6. In addition, the intensity ratio (I44° / I17°) of the peak at 2θ of 44° to the peak at 2θ of 17° can be in the range of 0.2 to 0.6, specifically it can be in the range of 0.3 to 0.5, and the intensity ratio (I44° / I8°) of the peak at 2θ of 44° to the peak at 2θ of 8° can be in the range of 0.2 to 0.4, specifically it can be in the range of 0.25 to 0.35.

[0064] And, in the XRD analysis, the intensity ratio (I17° / I36°) of the peak at 2θ of 17° to the peak at 2θ of 36° can be between 1.0 and 3.0, specifically in the range of 1.0 to 2.5.

[0065] Moreover, the intensity ratio (I 26° / I 8°) of the peak at 2θ = 26° to the peak at 2θ = 8° can be in the range of 0.3 to 0.7, specifically in the range of 0.4 to 0.6.

[0066]

Embodiments of the Invention

[0067] Hereinafter, embodiments of the present invention will be described in detail. However, this is only presented as an example and does not limit the present invention, which is only defined by the scope of the following claims.

[0068] (Examples 1 to 3)

[0069] First, 7 L of water was added to a 10 L double-jacketed reactor and heated to 50°C. Then, 1.49 kg of aluminum sulfate hydrate (Al2(SO4)3·mH2O (m is 14 to 18)) and 0.14 kg of lithium sulfate (Li2SO4) were added. The mixture was stirred at a speed of 200 rpm and completely dissolved within 30 minutes to obtain a mixed aqueous solution. Subsequently, the temperature of the mixed aqueous solution was adjusted to 70°C, 80°C, and 90°C for heating. After reaching the said temperature, 1.14 kg of 50 wt% sodium hydroxide (NaOH) was added for 1 hour. At the same time, the pH value of the solution was adjusted to about 7. In addition, the solution temperature was controlled not to exceed 100°C. After the reaction was completed, aging was carried out at a temperature above 60°C for 1 to 16 hours. After the aging was completed, the generated solid was separated by filtration and washed with 2 times (1 L) of pure water. The solid washed with pure water was filtered and then dried in an oven at 45°C for 24 hours, and finally 0.5 kg of an aluminum-based lithium adsorbent was prepared. At this time, the preparation yield of the aluminum-based lithium adsorbent was approximately 90%.

[0070] (Example 4)

[0071] 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 set to 90°C and the pH value was set to 11.07.

[0072] (Comparative Example 1)

[0073] An aluminum-based lithium adsorbent was prepared in the same manner as in Example 4, except that the pH was adjusted to 12.82.

[0074] (Comparative Example 2)

[0075] An aluminum-based lithium adsorbent was prepared in the same manner as in Example 1, except that LiOH was used instead of Li2SO4.

[0076] (Comparative Example 3)

[0077] An aluminum-based lithium adsorbent was prepared in the same manner as in Example 1, except that NaOH was added to the mixed aqueous solution of Al2(SO4)3·mH2O and Li2SO4 all at once.

[0078] Figure 2 XRD analysis results of the aluminum-based lithium adsorbents according to Examples 1 to 3 of the present invention are shown.

[0079] Reference Figure 2 , in the XRD analysis results of the aluminum-based lithium adsorbents in Examples 1 to 3 of the present invention, representative peaks of Li2SO4·4Al(OH)3·nH2O at 2θ of 8°, 17°, 20°, 26°, 36°, 38° and 44° were clearly formed. Therefore, it can be judged that the prepared aluminum-based lithium adsorbent has excellent crystallinity.

[0080] Figure 3 XRD analysis results of the aluminum-based lithium adsorbents according to Examples 3 to 4 and Comparative Example 1 of the present invention are shown.

[0081] Reference Figure 3 , in the aluminum-based lithium adsorbents according to Examples 3 to 4 of the present invention, typical peaks of Li2SO4·4Al(OH)3·nH2O were clearly formed, so it can be confirmed that an adsorbent with excellent crystallinity was prepared.

[0082] On the contrary, in Comparative Example 1, the typical 2θ = 44° peak of Li2SO4·4Al(OH)3·nH2O disappeared, and the 2θ = 26° peak shifted to the left. In addition, other peaks were formed in addition to the typical peaks of Li2SO4·4Al(OH)3·nH2O. It can thus be confirmed that the crystal structure of the adsorbent according to Comparative Example 2 has changed.

[0083] In addition, from Figure 4 the scanning electron microscope (SEM) analysis results of the aluminum-based lithium adsorbents of Examples 3 to 4 and Comparative Example 1, it can be confirmed that the adsorbents according to Examples 3 and 4 have well-formed crystal phases. And the adsorbent is in the form of aggregated plate-like primary particles, and it can be confirmed that the broad faces of the plate-like primary particles are positioned at a certain angle with respect to the adsorbent surface. On the contrary, the particles of the adsorbent in Comparative Example 1 are in a molten and aggregated form.

[0084] Figure 5 SEM images of the adsorbents according to Comparative Example 2 and Comparative Example 3 are shown.

[0085] Figure 5 (a) shows the SEM image of the adsorbent according to Comparative Example 2, Figure 5 (b) shows the SEM image of the adsorbent according to Comparative Example 3.

[0086] Reference Figure 5 , when NaOH is added in one go ( Figure 5 (b)), nano-sized particles are formed; while when NaOH is added in stages ( Figure 5 (a)), particle growth up to the micron scale is observed. In addition, reference Figure 5 (a), plate-shaped primary particles aggregate to form micron-sized particles, and the wide surfaces of the plate-shaped primary particles cover the surface to form micron-sized particles.

[0087] Figure 6 shows the XRD analysis results before and after filtration and separation of the solid product formed after aging in Example 3 and washing with fresh water.

[0088] Reference Figure 6 , after washing with fresh water, the peak of residual Na2SO4 on the surface disappears, and the representative peaks of Li2SO4·4Al(OH)3·nH2O become clearer. Therefore, it can be confirmed that the purity of the aluminum-based lithium adsorbent prepared by washing with fresh water has been improved.

[0089] (Experimental Example)

[0090] Using the aluminum-based lithium adsorbent prepared according to Example 3 of the present invention, adsorption and desorption experiments of lithium were carried out in a lithium sulfate solution.

[0091] First, lithium sulfate solutions with dissolved concentrations of lithium sulfate of 970 ppm and 510 ppm were prepared respectively.

[0092] In the adsorption experiment, 100 mL lithium sulfate solutions with lithium concentrations of 1000 ppm and 500 ppm were prepared respectively. After adding 10 g of each adsorbent, stirring was carried out for 24 hours to achieve adsorption. Subsequently, it was placed in 100 mL of pure water and stirred again for 24 hours to achieve desorption. Finally, the lithium concentration in each solution was measured by ICP, and the adsorption rate and desorption rate were calculated.

[0093] The experimental results are summarized in Table 1 below.

[0094] [Table 1]

[0095]

[0096] Referring to Table 1, when using the aluminum-based lithium adsorbent prepared according to the present invention, it can be confirmed that the lithium adsorption rate in the lithium sulfate solution is about 12% to 20%, and the desorption rate is more than 90%.

[0097] The present invention is not limited to the above embodiments, but can be implemented in various different forms, and those skilled in the art to which the present invention pertains should understand that the present invention can be implemented in other specific forms without changing the technical idea or basic characteristics of the present invention. Therefore, it should be understood that the above embodiments are exemplary in all aspects and not restrictive.

Claims

1. An aluminum-based lithium adsorbent, wherein, In the XRD analysis, peaks appear at 2θ = 8°, 17°, 20° and 26°. The aluminum-based lithium adsorbent is represented by Chemical Formula 1 below. [Chemical Formula 1] Li2SO4·4Al(OH)3·nH2O (n is from 1 to 6).

2. The aluminum-based lithium adsorbent according to claim 1, wherein, 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.

3. The aluminum-based lithium adsorbent according to claim 1, wherein, 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.

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

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

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

7. The aluminum-based lithium adsorbent according to claim 1, wherein, In the XRD analysis, the intensity ratio of the 2θ = 26° peak to the 2θ = 8° peak is in the range of 0.3 to 0.

7.

8. The aluminum-based lithium adsorbent according to claim 1, wherein, Plate-shaped primary particles are located on the surface at a certain angle.

9. A method for preparing an aluminum-based lithium adsorbent, comprising: The step of dissolving aluminum sulfate and lithium sulfate in distilled water to prepare a mixed aqueous solution; The step of adding sodium hydroxide to the mixed aqueous solution to form a precipitate; The step of aging the solution with the formed precipitate to form a solid; And The step of separating the solid; wherein, 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. [Chemical Formula 1] Li2SO4·4Al(OH)3·nH2O (n is from 1 to 6).

10. The method for preparing an aluminum-based lithium adsorbent according to claim 9, wherein, The step of adding sodium hydroxide to the mixed aqueous solution to form a precipitate is carried out in the range of a pH value of about 7.0 to 11.

0.

11. The method for preparing an aluminum-based lithium adsorbent according to claim 9, wherein, In the step of adding sodium hydroxide to the mixed aqueous solution to form a precipitate, sodium hydroxide is added at a rate of 0.05 mol / min to 1.0 mol / min.

12. The method for preparing an aluminum-based lithium adsorbent according to claim 9, wherein, In the step of dissolving aluminum sulfate and lithium sulfate in distilled water to prepare a mixed aqueous solution, the aluminum sulfate and lithium sulfate are mixed at a molar ratio in the range of 2:1 to 4:

1.

13. The preparation method of the aluminum-based lithium adsorbent according to claim 9, wherein, In the step of adding sodium hydroxide to the mixed aqueous solution to form a precipitate, sodium hydroxide and aluminum sulfate are mixed at a molar ratio in the range of 1.5:1 to 4:

1.

14. The preparation method of the aluminum-based lithium adsorbent according to claim 9, wherein, In the step of adding sodium hydroxide to the mixed aqueous solution to form a precipitate, a precipitate is formed through the reaction of Reaction Formula 1 below. [Reaction Formula 1] 2Al2(SO4)3·mH2O + Li2SO4 + 12NaOH → Li2SO4·4Al(OH)3·nH2O + 6Na2SO4 (Here, n is from 1 to 6).

15. The preparation method of the aluminum-based lithium adsorbent according to claim 9, wherein, After dissolving aluminum sulfate and lithium sulfate in distilled water to prepare a mixed aqueous solution, It further includes the step of heating the mixed aqueous solution to 70°C to 90°C.

16. The preparation method of the aluminum-based lithium adsorbent according to claim 9, wherein, The step of adding sodium hydroxide to the mixed aqueous solution to form a precipitate is carried out at a temperature in the range of 70°C to 100°C.

17. The preparation method of the aluminum-based lithium adsorbent according to claim 9, wherein, The step of aging the solution with the formed precipitate is carried out at a temperature above 60°C for 1 hour to 24 hours.

18. The preparation method of the aluminum-based lithium adsorbent according to claim 9, wherein, After the step of separating the solid matter, it further includes a step of washing the separated solid matter with water.

19. The preparation method of the aluminum-based lithium adsorbent according to claim 18, wherein, After washing the separated solid matter with water, it includes a step of drying the washed solid matter within a temperature range of 40°C to 60°C for 24 to 48 hours.

Images