An aluminum-based lithium adsorbent and a method for preparing the same

Abstract

The present application relates to a kind of preparation method of aluminum-based lithium adsorbent with high adsorption capacity and high cycle, and the preparation process includes that soluble aluminum salt, soluble lithium salt and soluble doped element salt solution are fully mixed with special surfactant solution, then lye is added to adjust solution pH value, hydrothermal reaction is carried out under specific condition and is aged, and the aluminum-based lithium adsorbent precursor slurry is obtained, the adsorbent precursor slurry is filtered after washing, then drying and grinding are carried out, and the aluminum-based lithium adsorbent powder is obtained.The present application is reconstructed to the phase and surface properties of adsorbent by the cooperation of appropriate iron and copper elements and special surfactant simultaneously doped, so that the prepared lithium adsorbent has the characteristics of high adsorption capacity and good cycle stability, and the preparation process is simple and easy to batch preparation.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical materials technology and relates to a method for preparing an aluminum-based lithium adsorbent with high adsorption capacity, high stability and good selectivity. Background Technology

[0003] Currently, the main technologies for lithium extraction from salt lake brines in my country include precipitation, extraction, membrane separation, and adsorption. While membrane separation is relatively simple and efficient, the membrane modules are prone to poisoning, leading to high costs and hindering its large-scale industrial application. Precipitation, due to the generally low lithium content in salt lake brines, is not only energy-intensive but also requires large amounts of chemical reagents, resulting in poor overall economic efficiency. Extraction, although possessing a certain processing capacity and effective for some types of brines, has a complex process flow, and organic extractants are prone to failure in harsh brine environments, causing dissolution and residue, potentially leading to secondary pollution and equipment corrosion. In contrast, adsorption, with its high selectivity for lithium ions, low energy consumption, and environmental friendliness, is particularly suitable for treating the prevalent low-grade, high magnesium-to-lithium ratio salt lake brines in my country, thus becoming the focus of current technological research and application to promote the large-scale and economical development of salt lake lithium resources.

[0004] Common lithium adsorbents used in adsorption methods mainly include manganese-based ion sieves, titanium-based ion sieves, and aluminum-based lithium adsorbents. While manganese and titanium-based ion sieves possess advantages such as large adsorption capacity and high selectivity, their lithium-ion desorption and material regeneration processes typically rely on acid washing, leading to problems such as dissolution of active components and crystal structure collapse, severely limiting their cycle stability and practical application potential. The formula for aluminum-based lithium adsorbents is generally "LiCl·2Al(OH)3·nH2O" (Li / Al‐LDHs), where Li... + It entered the Al-O octahedral cavity and removed some Li. + Subsequently, it exhibits memory effect and steric hindrance effect, thereby realizing the Li in salt lake brine + Highly selective adsorption. Compared to manganese and titanium-based adsorbents, aluminum-based lithium adsorbents only require water washing during desorption and regeneration, avoiding the impact of large amounts of acid on equipment and the environment, thus offering greater advantages as a green process. Therefore, aluminum-based lithium adsorbents are currently the only industrially available lithium adsorbent product.

[0005] However, aluminum-based lithium adsorbents still suffer from problems such as low adsorption capacity, poor cycle performance, and poor selectivity.

[0006] Therefore, there is an urgent need to provide a method for preparing an aluminum-based lithium adsorbent that is simple in preparation process, has high adsorption capacity, good cyclicity and selectivity, and to obtain an aluminum-based lithium adsorbent using this method. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for preparing aluminum-based lithium adsorbents with high adsorption capacity and high recyclability. The technical solution of this invention is as follows:

[0008] This invention discloses a method for preparing an aluminum-based lithium adsorbent with high adsorption capacity and high recyclability, comprising the following steps:

[0009] (1) Dissolve the soluble aluminum salt, soluble lithium salt, soluble iron salt, and soluble copper salt in a solvent.

[0010] Mix thoroughly to obtain a lithium-aluminum-iron-copper mixed solution; in the lithium-aluminum-iron-copper mixed solution, the molar ratio of lithium to aluminum is 0.8~2:2, the molar ratio of iron to aluminum is 1:20~80, and the molar ratio of copper to aluminum is 1:20~80.

[0011] (2) The dispersant is added to the solvent and dissolved by ultrasonication to obtain a uniform dispersant solution; the dispersant is at least one of fatty alcohol polyoxyethylene ether, poloxamer 188, sodium carboxymethyl cellulose, polyvinyl alcohol, poly(2-ethyl-2-oxazoline), Span series (such as Span 20, Span 80), ammonium dodecyl sulfate and polyethylene glycol-4000 (PEG-4000);

[0012] (3) At a rotation speed of 1500~2000 r / min and a temperature of 30~90 ℃, the above dispersant solution is added to the above lithium-aluminum-iron-copper mixture and stirred evenly.

[0013] (4) Add the alkaline solution to the material obtained in step (3) for hydrothermal reaction and control the pH endpoint value. After the addition is completed, continue to keep warm and stir for hydrothermal reaction to obtain the adsorbent precursor slurry. The pH endpoint value is 5.0~6.5.

[0014] (5) The adsorbent precursor slurry obtained in step (4) is washed, filtered, dried and ground to obtain powdered aluminum-based lithium adsorbent.

[0015] This invention provides a method for preparing an aluminum-based lithium adsorbent with high adsorption capacity and high recyclability, step (1)

[0016] Ultrasonic mixing can be used. The mixing time should be greater than 10 minutes, including 10-120 minutes.

[0017] In a preferred embodiment of the present invention, the soluble aluminum salt is at least one of anhydrous aluminum chloride, hydrated aluminum chloride, anhydrous aluminum sulfate, hydrated aluminum sulfate, anhydrous aluminum nitrate, and hydrated aluminum nitrate.

[0018] In a preferred embodiment of the present invention, the soluble lithium salt is at least one of lithium chloride, lithium sulfate, and lithium nitrate.

[0019] In a preferred embodiment of the present invention, the soluble iron salt is at least one of ferric chloride, ferric sulfate, and ferric nitrate, and the soluble copper salt is at least one of copper chloride, copper ferric sulfate, and copper nitrate.

[0020] In a preferred embodiment of the present invention, the dispersant is at least one selected from fatty alcohol polyoxyethylene ether, poloxamer 188, sodium carboxymethyl cellulose, polyvinyl alcohol, poly(2-ethyl-2-oxazoline), ammonium dodecyl sulfate, and polyethylene glycol-4000 (PEG-4000). One optimal selection of the dispersant includes selecting at least two selected from fatty alcohol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, poloxamer 188, sodium carboxymethyl cellulose, polyvinyl alcohol, poly(2-ethyl-2-oxazoline), ammonium dodecyl sulfate, and polyethylene glycol-4000 (PEG-4000). As a further preferred embodiment, when the dispersant consists of two of the above substances, the mass ratio of the two is 0.4~0.6:0.6~0.4. For example, fatty alcohol polyoxyethylene ether and 0.5 g of polyvinyl alcohol are mixed in a mass ratio of 0.4~0.6:0.6~0.4. For example, mixing poloxamer 188 and polyethylene glycol-4000 at a mass ratio of 0.4~0.6:0.6~0.4 will yield better results.

[0021] In a preferred experimental scheme of the present invention, the alkaline solution is at least one of sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonia and urea, and the concentration of the alkaline solution is 4.0~25.0 wt%.

[0022] In a preferred experimental scheme of the present invention, the solvent in steps (1) and (2) is deionized water.

[0023] In a preferred experimental scheme of the present invention, in step (1), the molar ratio of lithium to aluminum in the soluble lithium salt, the soluble aluminum salt, the soluble iron salt and the soluble copper salt is 1.5:1.8~2:2, more preferably 1.5:1.9~2.1, the molar ratio of iron to aluminum is 1:40~80, more preferably 1:55~65, and the molar ratio of copper to aluminum is 1:40~80, more preferably 1:55~65.

[0024] In a preferred experimental scheme of the present invention, in step (1), the molar ratio of lithium to aluminum in the soluble lithium salt, the soluble aluminum salt and the soluble iron salt is 1.5:2, the molar ratio of iron to aluminum is 1:60, and the molar ratio of copper to aluminum is 1:60.

[0025] In a preferred experimental scheme of the present invention, in step (2), the total amount of various dispersants added is 0.2~2.0 wt% of the mass of the lithium-aluminum-iron-copper mixed solution, including 0.6~1.0 wt%.

[0026] In a preferred experimental scheme of the present invention, in step (2), the total amount of various dispersants added is 0.8 wt% of the mass of the lithium-aluminum-iron-copper mixed solution.

[0027] In a preferred experimental scheme of the present invention, in step (4), the hydrothermal reaction temperature is 30~90 ℃, and the reaction time is greater than or equal to 30 min, which includes 0.5~3.0 h. In industrial applications, after the hydrothermal reaction is completed, aging treatment can be carried out, and the aging treatment time is generally 12~48 h, which includes 18~24 h.

[0028] In step (5) of this invention, the adsorbent precursor slurry obtained in step (4) is stirred, washed and washed with alcohol, filtered, dried and ground to obtain powdered aluminum-based lithium adsorbent.

[0029] More preferably, in step (5), the stirring and washing is carried out with water, the amount of water is 20 to 60 times the mass of the aluminum-based lithium adsorbent precursor, the washing time is greater than or equal to 10 min, including 10 to 60 min, and the drying temperature is 50 to 80°C.

[0030] Principles and advantages

[0031] This invention employs a uniquely structured organic surfactant combined with specific doping ions to regulate the external morphology and internal crystal structure of aluminum-based lithium adsorbents, thereby achieving the preparation of aluminum-based lithium adsorbents with high capacity and good cycle stability. Compared with existing technologies, the technical concept and process principle of this invention have significant advantages, specifically reflected in:

[0032] 1) By using trace amounts of iron and copper ions in synergistic doping, the two ions replace part of the aluminum ions in the aluminum-based lithium adsorbent, which stabilizes the internal structure of the aluminum-based lithium adsorbent without reducing its capacity, thus ensuring that the adsorbent has high cycle stability and adsorption capacity.

[0033] 2) By selecting a dispersant with a specific structure, the present invention effectively suppresses the aggregation of adsorbent particles during the synthesis process by utilizing the steric hindrance effect generated by the dispersant, thereby increasing the specific surface area of ​​the adsorbent. The non-ionic structure of this type of dispersant does not affect the internal crystal structure of the adsorbent due to intercalation, and can effectively improve its adsorption capacity.

[0034] 3) The adsorbent prepared by this invention has the characteristics of high adsorption capacity, excellent cycleability and selectivity. Its adsorption capacity is 6~8 mg / g, and it can still maintain a high adsorption capacity after multiple cycles (such as after 8 cycles). It also has high adsorption selectivity for lithium, and can be well applied to the extraction of lithium from salt lake brine with high magnesium-to-lithium ratio. Attached Figure Description

[0035] Figure 1 The images show the XRD patterns of the aluminum-based lithium adsorbent powder prepared in Example 1 before and after water washing.

[0036] Figure 2 The image shows the actual aluminum-based lithium adsorbent powder prepared in Example 1.

[0037] Figure 3 This is a comparison chart showing the cycling performance of aluminum-based lithium adsorbent powders prepared in Comparative Example 3 and Example 1. Detailed Implementation

[0038] To better explain the present invention, the technical solution of the present invention will be further described and illustrated below with reference to specific embodiments, accompanying drawings, or tables.

[0039] Example 1

[0040] (1) Weigh 13 g AlCl3·6H2O, 1.42 g LiCl, 0.24 g FeCl3·6H2O and 0.22 g CuSO4·5H2O and dissolve them in 60 ml of deionized water (Li / Al molar ratio is 1.5:2, Fe / Al molar ratio and Cu / Al molar ratio are both 1:60), and mix them evenly by sonication for 30 min to obtain a lithium-aluminum-iron-copper mixed solution;

[0041] (2) 1.0 g of fatty alcohol polyoxyethylene ether (AEO-9) dispersant was slowly added to 60 ml of deionized water and sonicated for 30 min to obtain a uniform dispersant solution (the amount of dispersant added was 0.8 wt% of the mass of the lithium aluminum iron copper mixed solution).

[0042] (3) At a speed of 1800 r / min and a temperature of 60 °C, the above fatty alcohol polyoxyethylene ether solution was slowly added to the above lithium aluminum iron copper mixed solution and stirred for 20 min to mix evenly.

[0043] (4) Keep the rotation speed and hydrothermal temperature constant, add 3 mol / L sodium hydroxide dropwise to the mixed solution obtained in step (3) at a drop rate of 3 mL / min to carry out hydrothermal reaction, control the pH at the drop endpoint to be 6.0, continue to keep warm for 1 h after the addition is completed, and then age for 24 h to obtain aluminum-based lithium adsorbent precursor slurry;

[0044] (5) The above aluminum-based lithium adsorbent precursor slurry was stirred, washed and washed with alcohol, filtered, dried in a drying oven at 60°C for 24 h, and ground to obtain powdered aluminum-based lithium adsorbent.

[0045] The aluminum-based lithium adsorbent prepared in this embodiment was subjected to a static adsorption performance test (Li + The initial concentration was 310 ppm (the brine was taken from Xinjiang). ICP was used to test the Li before and after adsorption in the brine. + The change in concentration, after adsorption saturation, yielded an adsorption capacity of 7.21 mg / g. After multiple cycles of adsorption, the adsorption capacity was 7.04 mg / g (8 cycles).

[0046]

[0047] Example 2

[0048] (1) Weigh 13 g AlCl3·6H2O, 1.42 g LiCl, 0.24 g FeCl3·6H2O and 0.22 g CuSO4·5H2O and dissolve them in 60 ml of deionized water (Li / Al molar ratio is 1.5:2, Fe / Al molar ratio and Cu / Al molar ratio are both 1:60), and mix them evenly by sonication for 30 min to obtain a lithium-aluminum-iron-copper mixed solution;

[0049] (2) Slowly add 1.0 g of polyvinyl alcohol dispersant to 60 ml of deionized water and sonicate for 30 min to obtain a uniform dispersant solution (the amount of dispersant added is 0.8 wt% of the mass of the lithium, aluminum, iron and copper mixed solution).

[0050] (3) At a speed of 1800 r / min and a temperature of 60 °C, the above polyvinyl alcohol solution was slowly added to the above lithium-aluminum-iron-copper mixed solution and stirred for 20 min until it was evenly mixed.

[0051] (4) Keep the rotation speed and hydrothermal temperature constant, add 3 mol / L sodium hydroxide dropwise to the mixed solution obtained in step (3) at a drop rate of 3 mL / min to carry out hydrothermal reaction, control the pH at the drop endpoint to be 6.0, continue to keep warm for 1 h after the addition is completed, and then age for 24 h to obtain aluminum-based lithium adsorbent precursor slurry;

[0052] (5) The above aluminum-based lithium adsorbent precursor slurry was stirred, washed and washed with alcohol, filtered, dried in a drying oven at 60°C for 24 h, and ground to obtain powdered aluminum-based lithium adsorbent.

[0053] The aluminum-based lithium adsorbent prepared in this embodiment was subjected to static adsorption performance testing (Li +The initial concentration was 310 ppm (the brine was taken from Xinjiang). ICP was used to test the Li before and after adsorption in the brine. + The change in concentration, after adsorption saturation, yielded an adsorption capacity of 6.53 mg / g. After multiple cycles of adsorption, the adsorption capacity was 6.41 mg / g (8 cycles).

[0054] Example 3

[0055] (1) Weigh 13 g AlCl3·6H2O, 1.42 g LiCl, 0.24 g FeCl3·6H2O and 0.22 g CuSO4·5H2O and dissolve them in 60 ml of deionized water (Li / Al molar ratio is 1.5:2, Fe / Al molar ratio and Cu / Al molar ratio are both 1:60), and mix them evenly by sonication for 30 min to obtain a lithium-aluminum-iron-copper mixed solution;

[0056] (2) Slowly add 1.0 g of poloxamer 188 dispersant to 60 ml of deionized water and sonicate for 30 min to obtain a homogeneous dispersant solution (the amount of dispersant added is 0.8 wt% of the mass of the lithium, aluminum, iron and copper mixed solution).

[0057] (3) At a speed of 1800 r / min and a temperature of 60 °C, the above poloxamer 188 solution was slowly added to the above lithium-aluminum-iron-copper mixed solution and stirred for 20 min until it was evenly mixed.

[0058] (4) Keep the rotation speed and hydrothermal temperature constant, add 3 mol / L sodium hydroxide dropwise to the mixed solution obtained in step (3) at a drop rate of 3 mL / min to carry out hydrothermal reaction, control the pH at the drop endpoint to be 6.0, continue to keep warm for 1 h after the addition is completed, and then age for 24 h to obtain aluminum-based lithium adsorbent precursor slurry;

[0059] (5) The above aluminum-based lithium adsorbent precursor slurry was stirred, washed and washed with alcohol, filtered, dried in a drying oven at 60°C for 24 h, and ground to obtain powdered aluminum-based lithium adsorbent.

[0060] The aluminum-based lithium adsorbent prepared in this embodiment was subjected to a static adsorption performance test (Li + The initial concentration was 310 ppm (the brine was taken from Xinjiang). ICP was used to test the Li before and after adsorption in the brine. + The change in concentration, after adsorption saturation, yielded an adsorption capacity of 6.69 mg / g. After multiple cycles of adsorption, the adsorption capacity was 6.58 mg / g (8 cycles).

[0061] Example 4

[0062] (1) Weigh 13 g AlCl3·6H2O, 1.42 g LiCl, 0.24 g FeCl3·6H2O and 0.22 g CuSO4·5H2O and dissolve them in 60 ml of deionized water (Li / Al molar ratio is 1.5:2, Fe / Al molar ratio and Cu / Al molar ratio are both 1:60), and mix them evenly by sonication for 30 min to obtain a lithium-aluminum-iron-copper mixed solution;

[0063] (2) 1.0 g of polyethylene glycol-4000 (PEG-4000) dispersant was slowly added to 60 ml of deionized water and sonicated for 30 min to obtain a homogeneous dispersant solution (the amount of dispersant added was 0.8 wt% of the mass of the lithium aluminum iron copper mixed solution).

[0064] (3) At a speed of 1800 r / min and a temperature of 60 ℃, the above polyethylene glycol-4000 solution was slowly added to the above lithium aluminum iron copper mixed solution and stirred for 20 min to mix evenly;

[0065] (4) Keep the rotation speed and hydrothermal temperature constant, add 3 mol / L sodium hydroxide dropwise to the mixed solution obtained in step (3) at a drop rate of 3 mL / min to carry out hydrothermal reaction, control the pH at the drop endpoint to be 6.0, continue to keep warm for 1 h after the addition is completed, and then age for 24 h to obtain aluminum-based lithium adsorbent precursor slurry;

[0066] (5) The above aluminum-based lithium adsorbent precursor slurry was stirred, washed and washed with alcohol, filtered, dried in a drying oven at 60°C for 24 h, and ground to obtain powdered aluminum-based lithium adsorbent.

[0067] The aluminum-based lithium adsorbent prepared in this embodiment was subjected to a static adsorption performance test (Li + The initial concentration was 310 ppm (the brine was taken from Xinjiang). ICP was used to test the Li before and after adsorption in the brine. + The change in concentration, after adsorption saturation, yielded an adsorption capacity of 6.80 mg / g. After multiple cycles of adsorption, the adsorption capacity was 6.68 mg / g (8 cycles).

[0068] Example 5

[0069] (1) Weigh 13 g AlCl3·6H2O, 1.42 g LiCl, 0.24 g FeCl3·6H2O and 0.22 g CuSO4·5H2O and dissolve them in 60 ml of deionized water (Li / Al molar ratio is 1.5:2, Fe / Al molar ratio and Cu / Al molar ratio are both 1:60), and mix them evenly by sonication for 30 min to obtain a lithium-aluminum-iron-copper mixed solution;

[0070] (2) 0.5 g of fatty alcohol polyoxyethylene ether (AEO-9) and 0.5 g of polyvinyl alcohol dispersant were slowly added to 60 ml of deionized water and sonicated for 30 min to obtain a uniform dispersant solution (the total amount of dispersant added was 0.8 wt% of the mass of the lithium aluminum iron copper mixed solution).

[0071] (3) At a speed of 1800 r / min and a temperature of 60 ℃, the above fatty alcohol polyoxyethylene ether and polyvinyl alcohol mixed solution were slowly added to the above lithium aluminum iron copper mixed solution and stirred for 20 min to mix evenly.

[0072] (4) Keep the rotation speed and hydrothermal temperature constant, add 3 mol / L sodium hydroxide dropwise to the mixed solution obtained in step (3) at a drop rate of 3 mL / min to carry out hydrothermal reaction, control the pH at the drop endpoint to be 6.0, continue to keep warm for 1 h after the addition is completed, and then age for 24 h to obtain aluminum-based lithium adsorbent precursor slurry;

[0073] (5) The above aluminum-based lithium adsorbent precursor slurry was stirred, washed and washed with alcohol, filtered, dried in a drying oven at 60°C for 24 h, and ground to obtain powdered aluminum-based lithium adsorbent.

[0074] The aluminum-based lithium adsorbent prepared in this embodiment was subjected to a static adsorption performance test (Li + The initial concentration was 310 ppm (the brine was taken from Xinjiang). ICP was used to test the Li before and after adsorption in the brine. + The change in concentration, after adsorption saturation, yielded an adsorption capacity of 7.86 mg / g. After multiple cycles of adsorption, the adsorption capacity was 7.69 mg / g (8 cycles).

[0075] Example 6

[0076] (1) Weigh 13 g AlCl3·6H2O, 1.42 g LiCl, 0.24 g FeCl3·6H2O and 0.22 g CuSO4·5H2O and dissolve them in 60 ml of deionized water (Li / Al molar ratio is 1.5:2, Fe / Al molar ratio and Cu / Al molar ratio are both 1:60), and mix them evenly by sonication for 30 min to obtain a lithium-aluminum-iron-copper mixed solution;

[0077] (2) 0.5 g poloxamer 188 and 0.5 g polyethylene glycol-4000 (PEG-4000) dispersant were slowly added to 60 ml of deionized water and sonicated for 30 min to obtain a uniform dispersant solution (the total amount of dispersant added was 0.8 wt% of the mass of the lithium aluminum iron copper mixed solution).

[0078] (3) At a speed of 1800 r / min and a temperature of 60 ℃, the above mixed solution of poloxamer 188 and polyethylene glycol-4000 was slowly added to the above mixed solution of lithium, aluminum, iron and copper, and stirred for 20 min to mix evenly.

[0079] (4) Keep the rotation speed and hydrothermal temperature constant, add 3 mol / L sodium hydroxide dropwise to the mixed solution obtained in step (3) at a drop rate of 3 mL / min to carry out hydrothermal reaction, control the pH at the drop endpoint to be 6.0, continue to keep warm for 1 h after the addition is completed, and then age for 24 h to obtain aluminum-based lithium adsorbent precursor slurry;

[0080] (5) The above aluminum-based lithium adsorbent precursor slurry was stirred, washed and washed with alcohol, filtered, dried in a drying oven at 60°C for 24 h, and ground to obtain powdered aluminum-based lithium adsorbent.

[0081] The aluminum-based lithium adsorbent prepared in this embodiment was subjected to a static adsorption performance test (Li + The initial concentration was 310 ppm (the brine was taken from Xinjiang). ICP was used to test the Li before and after adsorption in the brine. + The change in concentration, after adsorption saturation, yielded an adsorption capacity of 7.34 mg / g. After multiple cycles of adsorption, the adsorption capacity was 7.12 mg / g (8 cycles).

[0082] Example 7

[0083] (1) Weigh 13 g AlCl3·6H2O, 1.42 g LiCl, 0.24 g FeCl3·6H2O and 0.22 g CuSO4·5H2O and dissolve them in 60 ml of deionized water (Li / Al molar ratio is 1.5:2, Fe / Al molar ratio and Cu / Al molar ratio are both 1:60), and mix them evenly by sonication for 30 min to obtain a lithium-aluminum-iron-copper mixed solution;

[0084] (2) 0.5 g of fatty alcohol polyoxyethylene ether (AEO-9) dispersant was slowly added to 60 ml of deionized water and sonicated for 30 min to obtain a uniform dispersant solution (the amount of dispersant added was 0.4 wt% of the mass of the lithium aluminum iron copper mixed solution).

[0085] (3) At a speed of 1800 r / min and a temperature of 60 °C, the above fatty alcohol polyoxyethylene ether solution was slowly added to the above lithium aluminum iron copper mixed solution and stirred for 20 min to mix evenly.

[0086] (4) Keep the rotation speed and hydrothermal temperature constant, add 3 mol / L sodium hydroxide dropwise to the mixed solution obtained in step (3) at a drop rate of 3 mL / min to carry out hydrothermal reaction, control the pH at the drop endpoint to be 6.0, continue to keep warm for 1 h after the addition is completed, and then age for 24 h to obtain aluminum-based lithium adsorbent precursor slurry;

[0087] (5) The above aluminum-based lithium adsorbent precursor slurry was stirred, washed and washed with alcohol, filtered, dried in a drying oven at 60°C for 24 h, and ground to obtain powdered aluminum-based lithium adsorbent.

[0088] The aluminum-based lithium adsorbent prepared in this embodiment was subjected to a static adsorption performance test (Li + The initial concentration was 310 ppm (the brine was taken from Xinjiang). ICP was used to test the Li before and after adsorption in the brine. + The change in concentration, after adsorption saturation, yielded an adsorption capacity of 6.56 mg / g. After multiple cycles of adsorption, the adsorption capacity was 6.32 mg / g (8 cycles).

[0089] Example 8

[0090] (1) Weigh 13 g AlCl3·6H2O, 1.42 g LiCl, 0.24 g FeCl3·6H2O and 0.22 g CuSO4·5H2O and dissolve them in 60 ml of deionized water (Li / Al molar ratio is 1.5:2, Fe / Al molar ratio and Cu / Al molar ratio are both 1:60), and mix them evenly by sonication for 30 min to obtain a lithium-aluminum-iron-copper mixed solution;

[0091] (2) Slowly add 0.25 g of fatty alcohol polyoxyethylene ether dispersant to 60 ml of deionized water and sonicate for 30 min to obtain a uniform dispersant solution (the amount of dispersant added is 0.2 wt% of the mass of the lithium aluminum iron copper mixed solution).

[0092] (3) At a speed of 1800 r / min and a temperature of 60 °C, the above fatty alcohol polyoxyethylene ether solution was slowly added to the above lithium aluminum iron copper mixed solution and stirred for 20 min to mix evenly.

[0093] (4) Keep the rotation speed and hydrothermal temperature constant, add 3 mol / L sodium hydroxide dropwise to the mixed solution obtained in step (3) at a drop rate of 3 mL / min to carry out hydrothermal reaction, control the pH at the drop endpoint to be 6.0, continue to keep warm for 1 h after the addition is completed, and then age for 24 h to obtain aluminum-based lithium adsorbent precursor slurry;

[0094] (5) The above aluminum-based lithium adsorbent precursor slurry was stirred, washed and washed with alcohol, filtered, dried in a drying oven at 60°C for 24 h, and ground to obtain powdered aluminum-based lithium adsorbent.

[0095] The aluminum-based lithium adsorbent prepared in this embodiment was subjected to a static adsorption performance test (Li + The initial concentration was 310 ppm (the brine was taken from Xinjiang). ICP was used to test the Li before and after adsorption in the brine. + The change in concentration, after adsorption saturation, yielded an adsorption capacity of 6.02 mg / g. After multiple cycles of adsorption, the adsorption capacity was 5.88 mg / g (8 cycles).

[0096] Example 9

[0097] (1) Weigh 13 g AlCl3·6H2O, 1.42 g LiCl, 0.73 g FeCl3·6H2O and 0.67 g CuSO4·5H2O and dissolve them in 60 ml of deionized water (Li / Al molar ratio is 1.5:2, Fe / Al molar ratio and Cu / Al molar ratio are both 1:20), and mix them evenly by sonication for 30 min to obtain a lithium-aluminum-iron-copper mixed solution;

[0098] (2) 1.0 g of fatty alcohol polyoxyethylene ether (AEO-9) dispersant was slowly added to 60 ml of deionized water and sonicated for 30 min to obtain a uniform dispersant solution (the amount of dispersant added was 0.8 wt% of the mass of the lithium aluminum iron copper mixed solution).

[0099] (3) At a speed of 1800 r / min and a temperature of 60 °C, the above fatty alcohol polyoxyethylene ether solution was slowly added to the above lithium aluminum iron copper mixed solution and stirred for 20 min to mix evenly.

[0100] (4) Keep the rotation speed and hydrothermal temperature constant, add 3 mol / L sodium hydroxide dropwise to the mixed solution obtained in step (3) at a drop rate of 3 mL / min to carry out hydrothermal reaction, control the pH at the drop endpoint to be 6.0, continue to keep warm for 1 h after the addition is completed, and then age for 24 h to obtain aluminum-based lithium adsorbent precursor slurry;

[0101] (5) The above aluminum-based lithium adsorbent precursor slurry was stirred, washed and washed with alcohol, filtered, dried in a drying oven at 60°C for 24 h, and ground to obtain powdered aluminum-based lithium adsorbent.

[0102] The aluminum-based lithium adsorbent prepared in this embodiment was subjected to a static adsorption performance test (Li + The initial concentration was 310 ppm (the brine was taken from Xinjiang). ICP was used to test the Li before and after adsorption in the brine. +The change in concentration, after adsorption saturation, yielded an adsorption capacity of 6.11 mg / g. After multiple cycles of adsorption, the adsorption capacity was 5.94 mg / g (8 cycles).

[0103] Example 10

[0104] (1) Weigh 13 g AlCl3·6H2O, 1.42 g LiCl, 0.18 g FeCl3·6H2O and 0.17 g CuSO4·5H2O and dissolve them in 60 ml of deionized water (Li / Al molar ratio is 1.5:2, Fe / Al molar ratio and Cu / Al molar ratio are both 1:80), and mix them evenly by sonication for 30 min to obtain a lithium-aluminum-iron-copper mixed solution;

[0105] (2) 1.0 g of fatty alcohol polyoxyethylene ether (AEO-9) dispersant was slowly added to 60 ml of deionized water and sonicated for 30 min to obtain a uniform dispersant solution (the amount of dispersant added was 0.8 wt% of the mass of the lithium aluminum iron copper mixed solution).

[0106] (3) At a speed of 1800 r / min and a temperature of 60 °C, the above fatty alcohol polyoxyethylene ether solution was slowly added to the above lithium aluminum iron copper mixed solution and stirred for 20 min to mix evenly.

[0107] (4) Keep the rotation speed and hydrothermal temperature constant, add 3 mol / L sodium hydroxide dropwise to the mixed solution obtained in step (3) at a drop rate of 3 mL / min to carry out hydrothermal reaction, control the pH at the drop endpoint to be 6.0, continue to keep warm for 1 h after the addition is completed, and then age for 24 h to obtain aluminum-based lithium adsorbent precursor slurry;

[0108] (5) The above aluminum-based lithium adsorbent precursor slurry was stirred, washed and washed with alcohol, filtered, dried in a drying oven at 60°C for 24 h, and ground to obtain powdered aluminum-based lithium adsorbent.

[0109] The aluminum-based lithium adsorbent prepared in this embodiment was subjected to a static adsorption performance test (Li + The initial concentration was 310 ppm (the brine was taken from Xinjiang). ICP was used to test the Li before and after adsorption in the brine. + The change in concentration, after adsorption saturation, yielded an adsorption capacity of 6.34 mg / g. After multiple cycles of adsorption, the adsorption capacity was 6.12 mg / g (8 cycles).

[0110] Comparative Example 1

[0111] (1) Weigh 13 g AlCl3·6H2O and 1.42 g LiCl and dissolve them in 120 ml of deionized water (Li / Al molar ratio is 1.5:2). Mix them evenly by sonication for 30 min to obtain a lithium-aluminum mixed solution.

[0112] (2) At a rotation speed of 1800 r / min and a temperature of 60 °C, 3 mol / L sodium hydroxide was added dropwise to the above lithium-aluminum mixed solution at a dropping rate of 3 mL / min to carry out hydrothermal reaction. The pH at the dropwise endpoint was controlled to be 6.0. After the addition was completed, the temperature was kept for 1 h and then aged for 24 h to obtain aluminum-based lithium adsorbent precursor slurry.

[0113] (3) The above aluminum-based lithium adsorbent precursor slurry was stirred, washed and washed with alcohol, filtered, dried in a drying oven at 60°C for 24 h, and ground to obtain powdered aluminum-based lithium adsorbent.

[0114] The comparative aluminum-based lithium adsorbent prepared in this comparative example was used to conduct a static adsorption performance test experiment (Li). + The initial concentration was 310 ppm (the brine was taken from Xinjiang). ICP was used to test the Li before and after adsorption in the brine. + The change in concentration, after adsorption saturation, yielded an adsorption capacity of 4.84 mg / g. After multiple cycles of adsorption, the adsorption capacity was 3.64 mg / g (8 cycles).

[0115] Comparative Example 2

[0116] (1) Weigh 13 g AlCl3·6H2O, 1.42 g LiCl, 0.24 g FeCl3·6H2O and 0.22 g CuSO4·5H2O and dissolve them in 120 ml of deionized water (Li / Al molar ratio is 1.5:2, Fe / Al and Cu / Al molar ratio are both 1:60), and mix them evenly by sonication for 30 min to obtain a lithium-aluminum-iron-copper mixed solution;

[0117] (2) At a speed of 1800 r / min and a temperature of 60 °C, 3 mol / L sodium hydroxide was added dropwise to the above lithium-aluminum-iron-copper mixed solution at a dropping rate of 3 mL / min to carry out hydrothermal reaction. The pH at the dropwise endpoint was controlled to be 6.0. After the addition was completed, the temperature was kept for 1 h and then aged for 24 h to obtain aluminum-based lithium adsorbent precursor slurry.

[0118] (3) The above aluminum-based lithium adsorbent precursor slurry was stirred, washed and washed with alcohol, filtered, dried in a drying oven at 60°C for 24 h, and ground to obtain powdered aluminum-based lithium adsorbent.

[0119] The comparative aluminum-based lithium adsorbent prepared in this comparative example was used to conduct a static adsorption performance test experiment (Li).+ The initial concentration was 310 ppm (the brine was taken from Xinjiang). ICP was used to test the Li before and after adsorption in the brine. + The change in concentration, after adsorption saturation, yielded an adsorption capacity of 5.52 mg / g. After multiple cycles of adsorption, the adsorption capacity was 5.35 mg / g (8 cycles).

[0120] Comparative Example 3

[0121] (1) Weigh 13 g AlCl3·6H2O and 1.42 g LiCl and dissolve them in 60 ml of deionized water (Li / Al molar ratio is 1.5:2). Mix them evenly by sonication for 30 min to obtain a lithium-aluminum mixed solution.

[0122] (2) 1.0 g of fatty alcohol polyoxyethylene ether (AEO-9) dispersant was slowly added to 60 ml of deionized water and sonicated for 30 min to obtain a uniform dispersant solution (the amount of dispersant added was 0.8 wt% of the mass of the lithium aluminum mixed solution).

[0123] (3) At a speed of 1800 r / min and a temperature of 60 °C, the above fatty alcohol polyoxyethylene ether solution was slowly added to the above lithium aluminum mixed solution and stirred for 20 min until it was mixed evenly.

[0124] (4) Keep the rotation speed and hydrothermal temperature constant, add 3 mol / L sodium hydroxide dropwise to the mixed solution obtained in step (3) at a drop rate of 3 mL / min to carry out hydrothermal reaction, control the pH at the drop endpoint to be 6.0, continue to keep warm for 1 h after the addition is completed, and then age for 24 h to obtain aluminum-based lithium adsorbent precursor slurry;

[0125] (5) The above aluminum-based lithium adsorbent precursor slurry was stirred, washed and washed with alcohol, filtered, dried in a drying oven at 60°C for 24 h, and ground to obtain powdered aluminum-based lithium adsorbent.

[0126] The comparative aluminum-based lithium adsorbent prepared in this comparative example was used to conduct a static adsorption performance test experiment (Li). + The initial concentration was 310 ppm (the brine was taken from Xinjiang). ICP was used to test the Li before and after adsorption in the brine. + The change in concentration, after adsorption saturation, yielded an adsorption capacity of 6.42 mg / g. After multiple cycles of adsorption, the adsorption capacity was 5.28 mg / g (8 cycles).

[0127] The above description is merely a preferred embodiment of the present invention, and therefore should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made in accordance with the scope of the patent and the contents of the specification should still fall within the scope of the present invention.

Claims

1. A method for preparing an aluminum-based lithium adsorbent with high adsorption capacity and high recyclability, characterized in that, Includes the following steps: (1) Dissolve the soluble aluminum salt, soluble lithium salt, soluble iron salt, and soluble copper salt in a solvent. Mix thoroughly to obtain a lithium-aluminum-iron-copper mixed solution; in the lithium-aluminum-iron-copper mixed solution, the molar ratio of lithium to aluminum is 0.8~2:2, the molar ratio of iron to aluminum is 1:20~80, and the molar ratio of copper to aluminum is 1:20~80. (2) The dispersant is added to the solvent and dissolved by ultrasonication to obtain a uniform dispersant solution; the dispersant is at least one of fatty alcohol polyoxyethylene ether, poloxamer 188, sodium carboxymethyl cellulose, polyvinyl alcohol, poly(2-ethyl-2-oxazoline), Span series, ammonium dodecyl sulfate and polyethylene glycol-4000; (3) Add the dispersant solution to the lithium-aluminum-iron-copper mixture at a rotation speed of 1500~2000 r / min and a temperature of 30~90 ℃, and stir until uniform; (4) Add the alkaline solution to the material obtained in step (3) for hydrothermal reaction and control the pH endpoint value. After the addition is completed, continue to keep warm and stir for hydrothermal reaction to obtain the adsorbent precursor slurry. The pH endpoint value is 5.0~6.

5. (5) The adsorbent precursor slurry obtained in step (4) is washed, filtered, dried and ground to obtain powdered aluminum-based lithium adsorbent.

2. The method for preparing an aluminum-based lithium adsorbent with high adsorption capacity and high recyclability according to claim 1, characterized in that: In step (1), the mixing method includes ultrasonic mixing; the mixing time is greater than 10 min.

3. The method for preparing an aluminum-based lithium adsorbent with high adsorption capacity and high recyclability according to claim 1, characterized in that: The soluble aluminum salt is at least one of anhydrous aluminum chloride, hydrated aluminum chloride, anhydrous aluminum sulfate, hydrated aluminum sulfate, anhydrous aluminum nitrate, and hydrated aluminum nitrate. The soluble lithium salt is at least one of lithium chloride, lithium sulfate, and lithium nitrate; The soluble iron salt is at least one of ferric chloride, ferric sulfate, and ferric nitrate, and the soluble copper salt is at least one of copper chloride, copper ferric sulfate, and copper nitrate.

4. The method for preparing an aluminum-based lithium adsorbent with high adsorption capacity and high recyclability according to claim 1, characterized in that: The dispersant is at least one selected from fatty alcohol polyoxyethylene ether, poloxamer 188, sodium carboxymethyl cellulose, polyvinyl alcohol, poly(2-ethyl-2-oxazoline), ammonium dodecyl sulfate, and polyethylene glycol-4000. One of the preferred options for the dispersant is fatty alcohol polyoxyethylene ether.

5. The method for preparing an aluminum-based lithium adsorbent with high adsorption capacity and high recyclability according to claim 1, characterized in that: The alkaline solution is at least one of sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonia, and urea, and the concentration of the alkaline solution is 4.0~25.0 wt%.

6. The method for preparing an aluminum-based lithium adsorbent with high adsorption capacity and high recyclability according to claim 1, characterized in that: The solvent used in steps (1) and (2) is deionized water.

7. The method for preparing an aluminum-based lithium adsorbent with high adsorption capacity and high recyclability according to claim 1, characterized in that: In step (1), the molar ratio of lithium to aluminum in the soluble lithium salt, soluble aluminum salt, soluble iron salt, and soluble copper salt is 1.5:1.8~2:2, more preferably 1.5:1.9~2.1; the molar ratio of iron to aluminum is 1:40~80, more preferably 1:55~65; and the molar ratio of copper to aluminum is 1:40~80, more preferably 1:55~65. As a further preferred embodiment, in step (1), the molar ratio of lithium to aluminum in the soluble lithium salt, soluble aluminum salt, and soluble iron salt is 1.5:2; the molar ratio of iron to aluminum is 1:60; and the molar ratio of copper to aluminum is 1:

60.

8. The method for preparing an aluminum-based lithium adsorbent with high adsorption capacity and high recyclability according to claim 1, characterized in that: In step (2), the total amount of each dispersant added is 0.2 to 2.0 wt% of the mass of the lithium-aluminum-iron-copper mixed solution, including 0.6 to 1.0 wt%. As a further preferred option, in step (2), the total amount of each dispersant added is 0.8 wt% of the mass of the lithium-aluminum-iron-copper mixed solution.

9. The method for preparing an aluminum-based lithium adsorbent with high adsorption capacity and high recyclability according to claim 1, characterized in that: In step (4), the hydrothermal reaction temperature is 30~90 ℃, and the reaction time is greater than or equal to 30 min, which includes 0.5~3.0 h. After the hydrothermal reaction is completed, aging treatment can be carried out, and the aging treatment time is generally 12~48 h, which includes 18~24 h.

10. The method for preparing an aluminum-based lithium adsorbent with high adsorption capacity and high recyclability according to claim 1, characterized in that: In step (5), the adsorbent precursor slurry obtained in step (4) is stirred, washed, and then washed with alcohol, filtered, dried, and ground to obtain powdered aluminum-based lithium adsorbent. In step (5), the stirring and washing is carried out with water, the amount of water is 20 to 60 times the mass of the aluminum-based lithium adsorbent precursor, the washing time is 10 to 60 min, and the drying temperature is 50 to 80 ℃.

Images