Aluminum-doped manganese-based lithium ion sieve, and preparation method and application thereof

Abstract

The application discloses an aluminum-doped manganese lithium ion sieve, and has a molecular formula of H 1.6 (Al x Mn 1‑x ) 1.6 O4, wherein 0.05<=x<=0.15, and a crystal form of the aluminum-doped manganese lithium ion sieve is a pure-phase spinel structure. The application also provides a preparation method and application of the aluminum-doped manganese lithium ion sieve. The manganese lithium ion sieve is modified by aluminum doping, the cell structure is more stable, the problem of easy solution loss of a traditional H 1.6 Mn 1.6 O4 lithium ion sieve is solved, the saturated adsorption capacity is improved, and the manganese lithium ion sieve can be repeatedly used for multiple cycles. In addition, the aluminum-doped manganese lithium ion sieve has a larger specific surface area, is beneficial to full contact with lithium ions in a water body, is beneficial to embedding and disembedding of the lithium ions, and is beneficial to maintaining the cycle stability of the material.

Description

Technical Field

[0001] This invention relates to lithium-ion sieve adsorbents, and particularly to an aluminum-doped manganese-based lithium-ion sieve, its preparation method, and its application. Technical Background

[0002] Lithium and its compounds are widely used in energy, aerospace, alloy materials, ceramics, construction, and chemical industries, and are known as the "energy element of the 21st century," representing an important strategic resource. China possesses abundant salt lake brines, containing approximately 85% of the country's total lithium resources. However, most of my country's salt lakes have a high magnesium-to-lithium ratio, making the efficient and selective extraction of lithium from salt lake brines a hot topic in lithium resource development and utilization.

[0003] Lithium-ion sieves are a class of adsorbents that selectively adsorb lithium from solution. They are produced by pre-introducing lithium ions into an inorganic compound, followed by recrystallization into a composite oxide. The lithium is then extracted using an eluent. The framework of the resulting lithium-ion sieve remains largely unchanged, ultimately forming a framework compound with a certain degree of porosity. Based on size effect, steric hindrance effect, and sieving effect, these compounds can remember and filter target lithium ions even in the presence of multiple ions. Manganese-based lithium-ion sieves, due to their stable spinel structure and unique three-dimensional tunnel structure, exhibit high adsorption capacity and good selectivity, and are widely recognized as a promising green adsorbent. The synthesis of manganese-based lithium-ion sieves mainly includes solid-phase methods (high-temperature solid-phase method, microwave sintering method) and liquid-phase methods (sol-gel method, precipitation method, and hydrothermal method). Among these methods, the high-temperature solid-state method is the most commonly used and easy to operate. It involves calcining easily fusible or decomposable lithium-containing compounds (lithium carbonate, lithium hydroxide, lithium nitrate, etc.) and manganese sources (manganese oxide, manganese trioxide, manganese carbonate, manganese acetate, etc.) at high temperatures in a specific ratio to obtain lithium-manganese-oxygen compounds. While the high-temperature solid-state method is simple to operate, has short steps, and is easy to industrialize, it also suffers from uneven reaction of raw material powders, partial volatilization of lithium salts, resulting in impurities in the product and poor product uniformity. The hydrothermal method can effectively solve the problems of uneven mixing of lithium and manganese sources during the synthesis of lithium-ion sieve precursors. Furthermore, its unique homogeneous nucleation mechanism allows for the preparation of novel compounds that cannot be synthesized by other methods. Therefore, replacing the high-temperature solid-state method with the homogeneous hydrothermal method to avoid uneven raw material reaction is of great significance.

[0004] Manganese-based lithium ion sieves mainly include HMn2O4 (λ-MnO2), H 1.33 Mn 1.67 O4(MnO2·0.31H2O), H 1.6 Mn 1.6 O4(MnO2·0.5H2O), whose corresponding precursors are LiMn2O4 and Li 1.33Mn 1.67 O4, Li 1.6 Mn 1.6 O4, where H 1.6 Mn 1.6 O4 has the highest theoretical adsorption capacity and good cycling performance, making it the most representative. However, H... 1.6 Mn 1.6 O4 still faces the problem of manganese dissolution, which not only reduces the adsorption capacity of ion sieves but also affects their recycling performance. Doping modification is considered the simplest and most effective method to reduce manganese dissolution loss in spinel adsorbents. Introducing dopant ions can increase the average valence of manganese in lithium manganese oxide spinel and reduce Mn. 3+ The content of certain metal ions, while suppressing the Jahn-Teller effect or enhancing the octahedral bonding force to stabilize the spinel structure, can improve the cycling stability of the material. Therefore, doping with suitable metal ions and optimizing the preparation process to prepare manganese-based lithium ion sieves with high adsorption and low solubility remains a difficult and hot issue in current lithium extraction from salt lakes.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] The purpose of this invention is to provide an aluminum-doped manganese lithium-ion sieve, its preparation method, and its application.

[0007] This invention proposes an aluminum-doped manganese-based lithium-ion sieve with the molecular formula: H 1.6 (Al x Mn 1-x ) 1.6 O4, wherein 0.05≤x≤0.15, and the crystal form of the aluminum-doped manganese lithium-ion sieve is a pure-phase spinel crystal form.

[0008] Preferably, the molar percentage of aluminum is 0.05 to 0.15.

[0009] This aluminum-doped manganese-based lithium-ion sieve exhibits high adsorption capacity, low manganese dissolution, and good cycle stability, enabling it to effectively and selectively adsorb lithium ions from salt lakes or seawater.

[0010] The above-mentioned method for preparing aluminum-doped manganese-based lithium-ion sieves includes the following steps:

[0011] a. Manganese carbonate is calcined at 600℃-800℃ to obtain manganese trioxide powder. A certain amount of manganese trioxide is mixed evenly with lithium hydroxide and placed at 120℃ for hydrothermal reaction. The product is filtered and dried to obtain a gray-green LiMnO2 intermediate.

[0012] b. Calcination of LiMnO2 at 350℃-600℃ yields Li 1.6 Mn1.6 O4. Further, Li 1.6 Mn 1.6 O4 was dispersed in a methanol solution of aluminum chloride, stirred to ensure full contact, and then evaporated to remove the methanol. The thoroughly mixed sample was calcined to obtain an aluminum-doped manganese-based lithium-ion sieve precursor, Li. 1.6 (Al x Mn 1-x ) 1.6 O4, where x = 0.05 ≤ x ≤ 0.15.

[0013] c. The aluminum-doped manganese-based lithium-ion sieve precursor Li 1.6 Mn 1.6 O4(Al) was acid-leached in 0.05-0.5M HCl for 4-12 hours, filtered, washed, and dried at 80℃ to obtain H. 1.6 (Al x Mn 1-x ) 1.6 O4, where x = 0.05 ≤ x ≤ 0.15.

[0014] Preferably, the manganese source in step a is obtained by calcining manganese carbonate in air, with a calcination temperature of 600℃-800℃, a heating rate of 5℃ / min, and a time of 4 hours.

[0015] Preferably, in step a, the LiMnO2 intermediate is prepared by hydrothermal method at a temperature of 120°C for 24 hours, with a stirring speed of 100 r / min-500 r / min; the amount of manganese trioxide is 95 g, the amount of lithium hydroxide is 100 g, and the volume of water is 600 mL.

[0016] Preferably, in step b, the LiMnO2 intermediate is calcined in air to obtain Li 1.6 Mn 1.6 O4, calcination temperature 350℃-600℃, time 4-10 hours, heating rate 5℃ / min;

[0017] Preferably, in step b, the Li 1.6 Mn 1.6 The amount of O4 used was 200g, and the molar percentage of aluminum was 0.05 to 0.15.

[0018] Preferably, in step b, the Li 1.6 Mn 1.6 The O4 and aluminum chloride are mixed by impregnation, with methanol as the dispersant and Li... 1.6 Mn 1.6 The solid-liquid ratio of O4 to methanol was 0.4 g / mL, the evaporation temperature was 50℃, and the evaporation time was 4 h.

[0019] Preferably, the fully mixed sample in step b is calcined at a temperature of 350-550°C for 16-24 hours at a heating rate of 5°C / min.

[0020] Preferably, in step c, the dilute acid is 0.05-0.5M HCl, the temperature is room temperature, the acid leaching time is 4-12 hours, and the solid-liquid ratio of the powder to the acid is 20g / L-50g / L.

[0021] The above-mentioned aluminum-doped manganese lithium ion sieve can be used as an adsorbent to remove lithium ions from water.

[0022] Preferably, when the aluminum-doped manganese lithium ion sieve is used for adsorption treatment in water, the amount of aluminum-doped manganese lithium ion sieve is 1g / L-10g / L, the initial concentration of lithium ions is 1mg / L-1000mg / L, and the solution system is an ammonia-ammonium chloride aqueous solution.

[0023] Preferably, the water body can be salt lake water or seawater, and the aluminum-doped manganese lithium ion sieve provided by the present invention can be used for the extraction of lithium from salt lakes or seawater.

[0024] The manganese-based lithium-ion sieve of this invention, through aluminum doping modification, has a more stable cell structure, solving the problem of traditional H 1.6 Mn 1.6 This invention addresses the problem of easy dissolution and damage of O4 lithium-ion sieves, and improves their saturated adsorption capacity, allowing for repeated recycling. Furthermore, the aluminum-doped manganese-based lithium-ion sieve of this invention has a large specific surface area, which facilitates sufficient contact with lithium ions in water, promotes lithium ion insertion and extraction, and helps maintain the material's cycling stability.

[0025] The present invention has the following advantages:

[0026] 1. The aluminum-doped manganese lithium-ion sieve provided by the present invention has a more stable structure, increased adsorption capacity, reduced manganese dissolution loss, and can be repeatedly recycled after aluminum doping.

[0027] 2. The aluminum-doped manganese lithium-ion sieve provided by this invention has excellent selectivity for lithium ions and can be applied to the separation of lithium in high magnesium-to-lithium ratios.

[0028] 3. The aluminum-doped manganese lithium ion sieve provided by the present invention has a large specific surface area, which is beneficial to exposing more active sites and facilitating the insertion and extraction of lithium ions.

[0029] 4. The aluminum-doped manganese lithium-ion sieve preparation process provided by this invention is simple, efficient, and low-cost, and can be well applied in industrial production. Attached Figure Description

[0030] Figure 1X-ray diffraction patterns of the aluminum-doped manganese lithium-ion sieve precursors prepared in Examples 1-3 and Comparative Examples 1-3;

[0031] Figure 2 The nitrogen adsorption-desorption curve of the aluminum-doped manganese lithium-ion sieve prepared in Example 3 is shown.

[0032] Figure 3 This is a schematic diagram illustrating the selective adsorption effect of the aluminum-doped manganese lithium-ion sieve prepared in Example 3 on lithium ions under various interfering ion coexistence conditions.

[0033] Figure 4 This is a schematic diagram showing the adsorption effect of the aluminum-doped manganese lithium-ion sieve prepared in Example 3 on lithium ions and the manganese dissolution in a cyclic experiment.

[0034] To more clearly demonstrate the technical solution and its effects provided by the present invention, the following detailed description of the aluminum-doped manganese lithium-ion sieve, its preparation method, and its application are provided by specific embodiments of the present invention. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0036] The following provides a detailed description of an aluminum-doped manganese-based lithium-ion sieve, its preparation method, and its applications. Contents not described in detail in the embodiments of this invention are prior art known to those skilled in the art.

[0037] Example 1

[0038] 200 g of manganese carbonate was placed in a muffle furnace and calcined at 800 °C for 4 hours at a heating rate of 5 °C / min to obtain Mn₂O₃ (product detected by XRD). 100 g of LiOH·H₂O, 95 g of Mn₂O₃, and 600 mL of deionized water were added to a high-pressure reactor and hydrothermally reacted at 120 °C with stirring at 200 r / min for 24 hours, then cooled to room temperature. The resulting solid product was filtered and dried in an oven at 80 °C to obtain LiMnO₂ (product detected by XRD).

[0039] LiMnO2 was placed in a muffle furnace and heated at a rate of 5 °C / min from room temperature to 450 °C for 4 hours to obtain the product Li. 1.6 Mn 1.6O4 (product analyzed by XRD). Based on an aluminum molar ratio (Al / Mn+Al molar ratio) of 0.05, 200g of Li... 1.6 Mn 1.6 O4 was dispersed in a methanol solution of AlCl3·6H2O (500 mL volume). After thorough stirring, the methanol was evaporated at 50 °C to remove the solvent. The thoroughly mixed sample after methanol removal was calcined at a rate of 5 °C / min, from room temperature to 350 °C, and calcined for 16 hours to obtain the aluminum-doped manganese-based lithium-ion sieve precursor Li. 1.6 (Al 0.05 Mn 0.95 ) 1.6 O4 (product detected by XRD).

[0040] The aluminum-doped manganese-based lithium-ion sieve precursors Li prepared in Examples 1-3 and Comparative Examples 1-3 were respectively used. 1.6 (Al 0.05 Mn 0.95 ) 1.6 O4 was leached in 0.1M HCl at a solid-liquid ratio of 50 g / L for 8 hours at room temperature. After filtration, washing with water, and drying, aluminum-doped manganese-based lithium-ion sieve product H was obtained. 1.6 (Al 0.05 Mn 0.95 ) 1.6 O4, ICP-MS was used to test the manganese content in the filtrate to obtain the manganese loss during the pickling process (see Table 1).

[0041] Manganese loss I Mn Calculation formula: I Mn =CV / m×100%, where C is the concentration of manganese ions in the filtrate after acid washing (g / L); V is the volume of HCl solution (L); and m is the mass of manganese in the precursor (g).

[0042] Example 2

[0043] The process and conditions are the same as in Example 1, except that the molar ratio of aluminum is 0.1 (i.e., the Al ion concentration in the methanol solution of AlCl3·6H2O is different from that in Example 1); the remaining process steps of Example 2 are exactly the same as those of Example 1, so they will not be described again.

[0044] In this embodiment, aluminum-doped manganese-based ion sieve product H was prepared. 1.6 (Al 0.1 Mn 0.9 ) 1.6 O4.

[0045] Example 3

[0046] The process and conditions are the same as in Example 1, except that the molar ratio of aluminum is 0.15 (i.e., the Al ion concentration in the methanol solution of AlCl3·6H2O is different from that in Example 1); the remaining process steps of Example 3 are exactly the same as those of Example 1, so they will not be described again.

[0047] In this embodiment, aluminum-doped manganese-based ion sieve product H was prepared. 1.6 (Al 0.15 Mn 0.85 ) 1.6 O4.

[0048] Example 4

[0049] 0.1 g of the lithium-ion sieve products prepared in Examples 1-3 and Comparative Examples 1-3 were respectively placed into 100 mL of a 50 mg / L Li₂ solution. + In a 0.1 mol / L ammonia-ammonium chloride buffer solution with pH=10, the adsorption time was 8 hours. The supernatant was taken to test the ion concentration in the solution, thus obtaining the adsorption capacity of the aluminum-doped manganese-based lithium ion sieve. The results are shown in Table 1. + The source is lithium chloride;

[0050] Adsorption capacity Q a Calculation formula: Q a =(C0-C e )V / m, where C0 is the initial concentration of lithium ions in the solution (mg / L); C e V represents the concentration of lithium ions in the solution after adsorption (mg / L); V represents the solution volume (L); and m represents the adsorbent mass (g).

[0051] Example 5

[0052] Prepare 20 mL of Li solution with a concentration of 10 mM. + Na + K + Ca 2+ Mg 2+ The mixed solution was adjusted to pH 8 using a 0.1 mol / L ammonia-ammonium chloride system, and then 0.2 g of the manganese-based ion sieve H prepared in Example 3 of this invention was added. 1.6 (Al 0.15 Mn 0.85 ) 1.6 O4 was added and stirred continuously at 25°C for 8 hours, then filtered. Finally, the concentration of Li in the filtrate was tested. + The concentration of H, thus obtaining the manganese ion sieve H 1.6 (Al 0.15 Mn 0.85 ) 1.6 The selective adsorption effect of O4 on lithium ions under various interfering ion coexistence conditions is shown in [reference needed]. Figure 3 The sources of interfering ions are lithium chloride, sodium chloride, potassium chloride, calcium chloride, and magnesium sulfate.

[0053] Removal rate R calculation formula: R = (C0 - C) e ) / C0×100%, where C0 is the initial concentration of lithium ions in the solution (mg / L), C e The concentration of lithium ions after adsorption is expressed in mg / L.

[0054] Allocation factor K d Calculation formula: K d =(C0-C e )V / (C e ·m), where C0 is the initial concentration of lithium ions in the solution (mg / L); C e denoted as ρ, where ρ is the concentration of lithium ions after adsorption (mg / L); V is the solution volume (L); and m is the adsorbent mass (g).

[0055] Example 6:

[0056] Example 4 adsorbed Li + Example 3 corresponds to the manganese-based ion sieve H 1.6 (Al 0.15 Mn 0.85 ) 1.6 O4 was desorbed using 0.1M dilute hydrochloric acid at a solid-liquid ratio of 50 g / L and a desorption time of 8 hours. Separation was performed by filtration, and the concentrations of manganese and lithium ions in the desorption solution were measured. The manganese loss and desorption amount during the cyclic experiment were obtained (see...). Figure 4 Then wash with deionized water until neutral, and dry at 80°C to obtain the manganese-based ion sieve H. 1.6 (Al 0.15 Mn 0.85 ) 1.6 O4 regeneration.

[0057] Add 0.1g of regenerated manganese-based ion sieve to 100ml of 50mg / L Li + In a 0.1 mol / L ammonia-ammonium chloride buffer solution, after adsorption at 25 °C for 8 h, the lithium ion concentration in the filtrate was measured to obtain the amount of lithium ions adsorbed during the cyclic experiment (see [reference]). Figure 4 The adsorption-desorption-regeneration process was repeated five times in a co-cycle experiment.

[0058] Desorption amount calculation formula Q d =CV, where C is the concentration of lithium ions in the desorption solution (mg / L) and V is the volume of the desorption solution (L).

[0059] Comparative Example 1

[0060] The process and conditions are the same as in Example 1. The difference between Comparative Example 1 and Example 1 is that the molar ratio of aluminum element is 0.2 (that is, the Al ion concentration in the methanol solution of AlCl3·6H2O is different from that in Example 1). The remaining process steps of Comparative Example 1 are exactly the same as those of Example 1, so they will not be described again.

[0061] In this embodiment, aluminum-doped manganese-based lithium-ion sieve product H was prepared. 1.6 (Al 0.2 Mn 0.8 ) 1.6 O4.

[0062] Comparative Example 2

[0063] The process and conditions are the same as in Example 1. The difference between Comparative Example 2 and Example 1 is that the molar ratio of aluminum element is 0.25 (i.e., the Al ion concentration in the methanol solution of AlCl3·6H2O is different from that in Example 1): 1. The remaining process steps of Comparative Example 2 are exactly the same as those of Example 1, so they will not be described again.

[0064] In this embodiment, aluminum-doped manganese-based lithium-ion sieve product H was prepared. 1.6 (Al 0.25 Mn 0.75 ) 1.6 O4.

[0065] Comparative Example 3

[0066] 200g of manganese carbonate was placed in a muffle furnace and calcined at 800℃ for 4 hours at a heating rate of 5℃ / min to obtain Mn2O3. 100g of LiOH·H2O, 95g of Mn2O3, and 600mL of deionized water were added to a smart high-pressure reactor and hydrothermally reacted at 120℃ with stirring for 24 hours, then cooled to room temperature. The resulting product was filtered and dried in an oven at 80℃ to obtain the LiMnO2 intermediate.

[0067] LiMnO2 was placed in a muffle furnace and calcined at 450℃ for 4 hours at a heating rate of 5℃ / min to obtain Li. 1.6 Mn 1.6 O4. The manganese-based lithium ion sieve precursor Li... 1.6 Mn 1.6 O4 was acid-leached in 0.1M HCl at a solid-liquid ratio of 50 g / L at room temperature for 8 hours. After filtration, washing, and drying, H was obtained. 1.6 Mn 1.6 O4.

[0068] In this embodiment, manganese-based lithium ion sieve product H was prepared. 1.6 Mn 1.6 O4.

[0069] Results Analysis

[0070] The aluminum-doped manganese-based lithium-ion sieves prepared in Examples 1-3 and Comparative Examples 1-3 of this invention were subjected to compositional analysis and performance testing, and the following experimental results were obtained:

[0071] (1) From Figure 1 It can be seen that: Li 1.6 Mn 1.6 The diffraction peaks of O4 indicate a spinel structure (JCPDS NO. 52-1841). When the molar percentage of aluminum is 0.05-0.2%, the diffraction peaks of the aluminum-doped manganese lithium-ion sieve precursors all show good crystallinity with no impurity peaks, indicating that the spinel structure is maintained after doping. That is, the crystal form of the prepared aluminum-doped manganese lithium-ion sieves is the pure-phase spinel crystal form. When the molar percentage of aluminum is 0.25%, the obtained aluminum-doped manganese lithium-ion sieve precursor Li... 1.6 (Al 0.25 Mn 0.75 ) 1.6 The diffraction peaks of O4 shifted to lower angles, indicating a decrease in interplanar spacing.

[0072] (2) The aluminum-doped manganese lithium ion sieve precursors prepared in Examples 1-3 and Comparative Examples 1-3 were delithiated with acid solution. The supernatant was taken to measure the manganese ion concentration in the solution and the manganese dissolution rate was calculated. The test results are shown in Table 1 below.

[0073] (3) The lithium adsorption capacity of the aluminum-doped manganese lithium ion sieves prepared in Examples 1-3 and Comparative Examples 1-3 was tested according to the method in Example 4. The test results are shown in Table 1 below.

[0074] Table 1. Manganese dissolution and adsorption capacity of aluminum-doped manganese lithium-ion sieves prepared in Examples 1-3 and Comparative Examples 1-3.

[0075] <![CDATA[H 1.6 Mn 1.6 O4]]> 2.10％ 23.6 mg / g <![CDATA[H 1.6 (Al 0.05 Mn 0.95 ) 1.6 O4]]> 2.08％ 27.5mg / g <![CDATA[Hi 1.6 (Al 0.1 Mn 0.9 ) 1.6 O4]]> 2.03％ 31.8 mg / g <![CDATA[H 1.6 (Al 0.15 Mn 0.85 ) 1.6 O4]]> 1.94％ 31.2 mg / g <![CDATA[H 1.6 (Al 0.2 Mn 0.8 ) 1.6 O4]]> 4.03％ 27.3 mg / g <![CDATA[H 1.6 (Al 0.25 Mn 0.75 ) 1.6 O4]]> 4.67％ —

[0076] Table 1 shows that a low proportion of aluminum doping can reduce manganese dissolution while increasing lithium adsorption. When the molar percentage of aluminum is 0.25, manganese dissolution is severe. Meanwhile, H... 1.6 (Al 0.25 Mn 0.75 ) 1.6 O4 was used as an adsorbent for lithium, but the adsorbed lithium could not be separated by centrifugation, indicating that a high proportion of aluminum doping is detrimental to its structural stability. Considering both adsorption capacity and stability, the optimal molar ratio of aluminum is 0.15.

[0077] (4) Appendix Figure 2 The manganese-based ion sieve H in Example 3 1.6 (Al 0.15 Mn0.85 ) 1.6 The BET curve of O4 shows a type II adsorption curve with an H4-type hysteresis loop, indicating that it is a microporous-mesoporous material with a specific surface area of ​​91 m². 2 / g. The BET ratio is 10-30m relative to most lithium adsorbents. 2 / g, which has significant advantages.

[0078] (5) The manganese-based ion sieve H prepared using Example 3 of the present invention 1.6 (Al 0.15 Mn 0.85 ) 1.6 O4 was used as an adsorbent, and adsorption experiments on lithium ions were conducted under the presence of other interfering ions. The lithium content was determined by ICP, thereby obtaining the partition factor of the adsorbent for lithium. The specific scheme is as described in Example 5, and the experimental results are as follows. Figure 3 As shown. By Figure 3 It can be seen that the aluminum-manganese-doped ion sieve H prepared in the embodiments of the present invention 1.6 (Al 0.15 Mn 0.85 ) 1.6 O4 achieved near-100% lithium removal from water despite interference from other competing ions, with a partition factor as high as 6 × 10⁻⁶. 4 mL / g, that is, the manganese-based ion sieve H prepared in Embodiment 3 of the present invention... 1.6 (Al 0.15 Mn 0.85 ) 1.6 O4 exhibits excellent selectivity when multiple interfering ions coexist.

[0079] (5) The manganese-based ion sieve H prepared using Example 3 of the present invention 1.6 (Al 0.15 Mn 0.85 ) 1.6 O4 was used as the adsorbent in a cyclic adsorption experiment, and the lithium and manganese contents were determined by ICP to obtain the adsorption capacity of the adsorbent for lithium and the manganese dissolution loss. The specific procedure is described in Example 6, and the experimental results are as follows. Figure 4 As shown. By Figure 4 It can be seen that the manganese-based ion sieve H prepared in Example 3 of this invention 1.6 (Al 0.15 Mn 0.85 ) 1.6 O4 still exhibits good adsorption performance even after multiple cycles, with manganese loss remaining below 5% after five cycles.

[0080] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An aluminum-doped manganese-based lithium-ion sieve, wherein the molecular formula of the aluminum-doped manganese-based lithium-ion sieve is: H 1.6 (Al x Mn 1- x ) 1.6 O4, of which 0.1≤x≤0.15, the crystal form of the aluminum-doped manganese lithium-ion sieve is a pure-phase spinel crystal form; The preparation method of the aluminum-doped manganese-based lithium-ion sieve includes the following steps: a. Manganese trioxide powder and lithium hydroxide aqueous solution are mixed evenly and placed in a high-pressure reactor for hydrothermal reaction. The product is filtered and dried to obtain LiMnO2. The amount of manganese trioxide in the hydrothermal reaction system is 90 g-110 g, the amount of lithium hydroxide is 90 g-100 g, the water volume is 500 mL-800 mL, the reaction temperature is 100℃-150℃, and the time is 24 h-48 h. b. Calcine the LiMnO2 obtained in a. above to obtain Li 1.6 Mn 1.6 O4, then Li 1.6 Mn 1.6 O4 was dispersed in a methanol solution of aluminum chloride, stirred and mixed thoroughly, and then evaporated to remove the methanol; after evaporation, the thoroughly mixed Li 1.6 Mn 1.6 Calcination of O4 with aluminum chloride samples yielded aluminum-doped manganese-based lithium-ion sieve precursor Li. 1.6 (Al x Mn 1-x ) 1.6 O4; where 0.1 ≤ x ≤ 0.15; c. Using aluminum-doped manganese-based lithium-ion sieve precursor Li 1.6 (Al x Mn 1-x ) 1.6 O4 is leached in acid to remove lithium, and after filtration, washing, and drying, H is obtained. 1.6 (Al x Mn 1-x ) 1.6 O4, where 0.1≤x≤0.15; The manganese trioxide mentioned in step a is obtained by calcining manganese carbonate in an air atmosphere. The manganese carbonate is calcined at 600℃-800℃ to obtain manganese trioxide.

2. A method for preparing an aluminum-doped manganese-based lithium-ion sieve as described in claim 1, characterized in that, Includes the following steps: a. Manganese trioxide powder and lithium hydroxide aqueous solution are mixed evenly and placed in a high-pressure reactor for hydrothermal reaction. The product is filtered and dried to obtain LiMnO2. The amount of manganese trioxide in the hydrothermal reaction system is 90 g-110 g, the amount of lithium hydroxide is 90 g-100 g, the water volume is 500 mL-800 mL, the reaction temperature is 100℃-150℃, and the time is 24 h-48 h. b. Calcine the LiMnO2 obtained in a. above to obtain Li 1.6 Mn 1.6 O4, then Li 1.6 Mn 1.6 O4 was dispersed in a methanol solution of aluminum chloride, stirred and mixed thoroughly, and then evaporated to remove the methanol; after evaporation, the thoroughly mixed Li 1.6 Mn 1.6 Calcination of O4 with aluminum chloride samples yielded aluminum-doped manganese-based lithium-ion sieve precursor Li. 1.6 (Al x Mn 1-x ) 1.6 O4; where 0.1 ≤ x ≤ 0.15; c. Using aluminum-doped manganese-based lithium-ion sieve precursor Li 1.6 (Al x Mn 1-x ) 1.6 O4 is leached in acid to remove lithium, and after filtration, washing, and drying, H is obtained. 1.6 (Al x Mn 1-x ) 1.6 O4, where 0.1≤x≤0.

15.

3. The preparation method according to claim 2, characterized in that: In step a, the LiMnO2 intermediate was prepared by hydrothermal method. During the reaction, mechanical stirring was carried out at a speed of 100 r / min-500 r / min.

4. The preparation method according to claim 2, characterized in that: In step b, LiMnO2 is calcined in air to obtain Li. 1.6 Mn 1.6 O4, roasting temperature 350℃-600℃, time 4-10 hours.

5. The preparation method according to claim 4, characterized in that: In step b, LiMnO2 is calcined in air to obtain Li. 1.6 Mn 1.6 O4, roasting temperature 400℃-500℃, time 4-6 hours.

6. The preparation method according to claim 2, characterized in that: In step b, Li 1.6 Mn 1.6 The O4 and aluminum chloride are mixed by impregnation, with methanol as the dispersant. The methanol evaporation temperature is 30℃~80℃, and the methanol evaporation time is 0.5 h~8 h. The Li 1.6 Mn 1.6 O4 and aluminum chloride are mixed and calcined, wherein the molar ratio of aluminum (Al / Mn+Al) is 0.1~0.15, and Li... 1.6 Mn 1.6 The solid-liquid ratio of O4 to methanol is 0.1 g / mL to 1 g / mL.

7. The preparation method according to claim 2, characterized in that: In step b, Li 1.6 Mn 1.6 The O4 and aluminum chloride are mixed by impregnation, with methanol as the dispersant. The methanol evaporation temperature is 30℃~50℃, and the methanol evaporation time is 2h~6h. Li 1.6 Mn 1.6 The solid-liquid ratio of O4 to methanol is 0.2 g / mL to 0.5 g / mL.

8. The preparation method according to claim 2, characterized in that: In step c, the acid is 0.05-0.5 M HCl, the temperature is room temperature, and the acid leaching time is 4-12 hours. The aluminum-doped manganese-based lithium-ion sieve precursor Li... 1.6 (Al x Mn 1-x ) 1.6 The solid-liquid ratio of O4 to acid is 20 g / L - 50 g / L.

9. The preparation method according to claim 2, characterized in that: The aluminum-doped manganese-based lithium-ion sieve precursor Li mentioned in step c 1.6 (Al x Mn 1-x ) 1.6 The solid-liquid ratio of O4 to acid is 40 g / L - 50 g / L.

10. The application of the aluminum-doped manganese lithium-ion sieve of claim 1 in lithium extraction from water.

11. The application according to claim 10, characterized in that, The amount of aluminum-doped manganese lithium-ion sieve used is 1g / L-10g / L of water, the initial lithium-ion concentration is 1mg / L-1000mg / L, and the aqueous solution system is a 0.1mol / L ammonia-0.1mol / L ammonium chloride buffer solution with pH=8~11.

12. The application according to claim 11, characterized in that, The initial lithium ion concentration is 50 mg / L-500 mg / L.

13. The application according to claim 10, characterized in that, The water body may be salt lake water and / or seawater.

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