Preparation method of high-powder supported aluminum adsorbent and aluminum adsorbent

Abstract

The invention discloses a preparation method of a high-powder supported aluminum adsorbent. The preparation method comprises the following steps: preparing a first solution from soluble aluminum salt and lithium salt; preparing a second solution by using soluble alkali; preparing a third solution by using a soluble polymer; mixing the second solution and the third solution to obtain a fourth solution; adding the fourth solution into the first solution, adjusting the pH value to a preset range, and reacting to obtain a mixture; washing, filtering and drying the mixture to obtain aluminum adsorbent precursor powder; and granulating the aluminum adsorbent precursor powder to obtain aluminum adsorbent particles. The method has the advantages of high powder load, high adsorption rate, high adsorption capacity, stability, reliability, reusability and the like, can be directly used for extracting Li < + > from original brine and old brine in the technical field of lithium extraction from liquid-phase salt lakes, and has very high practical application value and popularization value.

Description

Technical Field

[0001] This invention belongs to the field of lithium adsorbent preparation technology, specifically, it relates to a method for preparing a high powder-supported aluminum-based adsorbent and an aluminum-based adsorbent. Background Technology

[0002] Lithium, the lightest and least dense silvery-white alkali metal in nature, has been hailed as a "21st-century energy metal driving global progress" due to its unique advantages. In recent years, the rapid expansion of the lithium-ion battery industry has brought unprecedented development opportunities to the field of new energy materials. Compared to membrane separation, solution extraction, and electrodialysis, adsorption methods offer a significant cost advantage due to their simplicity, low cost, and high efficiency, enabling a one-step lithium extraction process from salt lakes.

[0003] Methods for extracting lithium from brine include aluminum-based adsorbents (Li / Al-LDHs), manganese-based and titanium-based lithium ion sieve adsorbents, etc. However, manganese / titanium-based ion sieve adsorbents typically require strong acid desorption for lithium desorption, which may increase costs and cause environmental pollution, making them unsuitable for use in ecologically fragile salt lake environments. Aluminum-based adsorbents have advantages such as ease of synthesis, elution with deionized water without dissolution loss, and good reusability. Furthermore, aluminum-based adsorbents are the only industrially applied adsorbents for lithium extraction from salt lake brine, demonstrating high application value in brine lithium extraction. However, current aluminum-based lithium adsorbents suffer from problems such as low adsorption capacity after granulation, low powder loading rate, and short cycle life. Ensuring high uniformity of adsorbent particles and high powder loading is a necessary prerequisite for efficient industrial adsorption.

[0004] Therefore, there is an urgent need to propose a method for preparing aluminum-based adsorbents that is simple in process, has high powder loading, fast adsorption rate and good stability, and to prepare aluminum-based adsorbents using this method. Summary of the Invention

[0005] To address the technical problems existing in the prior art, an embodiment of the present invention provides a method for preparing a high powder-loaded aluminum-based adsorbent and an aluminum-based adsorbent.

[0006] A method for preparing a high-powder-supported aluminum-based adsorbent according to one aspect of an embodiment of the present invention includes the following steps: preparing a first solution using soluble aluminum salt and lithium salt; preparing a second solution using soluble alkali; preparing a third solution using soluble polymer; mixing the second solution and the third solution to obtain a fourth solution; adding the fourth solution to the first solution and adjusting its pH value to a preset range, reacting to obtain a mixture; washing, filtering, and drying the mixture to obtain an aluminum-based adsorbent precursor powder; and granulating the aluminum-based adsorbent precursor powder to obtain aluminum-based adsorbent particles.

[0007] In one example of the preparation method provided above, the method for granulating the aluminum-based adsorbent precursor powder includes: mixing an organic solvent, an organic polymer, and the aluminum-based adsorbent precursor powder to form a slurry; and dropping the slurry into a flowing inorganic solvent to solidify and form aluminum-based adsorbent particles.

[0008] In one example of the preparation method provided above, the mass ratio of the organic solvent, the organic polymer, and the aluminum-based adsorbent precursor powder is (1-20):(0.1-2):(1-10).

[0009] In one example of the preparation method provided above, the pH value is preset to a range of 6.0 to 8.0.

[0010] In one example of the preparation method provided above, the soluble aluminum salt is at least one of anhydrous aluminum chloride, aluminum chloride hexahydrate, aluminum sulfate, hydrated aluminum sulfate, aluminum nitrate, hydrated aluminum nitrate, aluminum silicate, and aluminum sulfide; wherein the aluminum ion concentration of the soluble aluminum salt in the first solution is 0.1 to 10 mol / L.

[0011] In one example of the preparation method provided above, the lithium salt is at least one of anhydrous lithium chloride, hydrated lithium chloride, anhydrous lithium hydroxide, hydrated lithium hydroxide, lithium carbonate, lithium acetate, and lithium nitrate; wherein the lithium ion concentration of the lithium salt in the first solution is 0.1 to 10 mol / L.

[0012] In one example of the preparation method provided above, the soluble alkali is at least one of sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, ammonia, and urea; and / or, the alkali concentration of the second solution is 0.5 to 5 mol / L.

[0013] In one example of the preparation method provided above, the soluble polymer is at least one selected from polypropylene glycol, polyethylene oxide, polyethylene glycol-600, polyethylene glycol-1000, and polyethylene glycol-2000, and / or the concentration of the soluble polymer in the third solution is 0.1 to 1 mol / L.

[0014] In one example of the preparation method provided above, the organic polymer is at least one selected from polyacrylonitrile, polyvinyl alcohol, polyvinyl chloride, polyvinyl fluoride, and polyacrylamide; and / or, the organic solvent is at least one selected from N-methylpyrrolidone, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, and tetrahydrofuran.

[0015] The aluminum-based adsorbent provided according to another aspect of the present invention is prepared by the preparation method described above.

[0016] Beneficial Effects: This invention involves adding a soluble polymer to an alkaline solution, then mixing it with a soluble lithium salt. The resulting aluminum salt mixture is then used to prepare aluminum-based adsorbent precursor powder via a simple precipitation and intercalation reaction. During solvent-resistant extrusion granulation, the functional groups inherent in the soluble polymer effectively reduce powder agglomeration and powder shedding during use. Under the same binder ratio, the powder loading is more than twice that of ordinary aluminum-based adsorbent powder, effectively reducing the use of organic polymers and lowering costs. Furthermore, compared to aluminum-based adsorbent particles prepared by other methods, this invention achieves a powder loading rate of 87%, and the adsorption rate reaches equilibrium in a shorter time, even with 600 ppm Li. + In sulfate-type brine, the adsorption capacity is >9 mg / g. Furthermore, it can be directly applied to extract Li from raw brine and aged brine. + It can rapidly adsorb a large number of lithium ions in a short period of time, achieving efficient separation and extraction. Furthermore, the aluminum-based adsorbent particles of this invention exhibit high stability, maintaining a certain adsorption level during 10 cycles of use without any dissolution, demonstrating excellent structural stability.

[0017] Therefore, this invention has advantages such as high powder loading, fast adsorption rate, high adsorption capacity, stability and reliability, and reusability. In the field of lithium extraction from liquid-phase salt lakes, it can be directly applied to Li in raw brine and old brine. + Extraction has high practical application and promotion value. Attached Figure Description

[0018] The above and other aspects, features, and advantages of embodiments of the present invention will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0019] Figure 1 This is a flowchart illustrating the synthesis of a highly powder-supported aluminum-based adsorbent according to an embodiment of the present invention.

[0020] Figure 2 This is an adsorption curve of the high powder-loaded aluminum adsorbent prepared in the first specific synthesis example;

[0021] Figure 3 This is a schematic diagram of the highly powdered aluminum-based adsorbent prepared in the first specific synthesis example after 10 adsorption cycles.

[0022] Figure 4 This is a comparison diagram of the powder loading of various high powder-loaded aluminum adsorbent particles prepared in the specific synthesis example 2;

[0023] Figure 5 These are comparative scanning electron microscope cross-sectional images of the high powder-loaded aluminum adsorbent particles prepared in the specific synthesis example three. Detailed Implementation

[0024] Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention can be implemented in many different forms, and should not be construed as limited to the specific embodiments set forth herein. Rather, these embodiments are provided to explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the various embodiments of the invention and various modifications suitable for particular intended applications.

[0025] As used herein, the term "comprising" and its variations are open terms meaning "including but not limited to". The terms "based on", "according to", etc., mean "at least partially based on" or "at least partially according to". The terms "one embodiment" and "an embodiment" mean "at least one embodiment". The term "another embodiment" means "at least one other embodiment". The terms "first", "second", etc., may refer to different or the same objects. Other definitions, whether explicit or implicit, may be included below. Unless explicitly indicated by the context, the definition of a term remains consistent throughout the specification.

[0026] Figure 1 This is a flowchart illustrating the synthesis process of a highly powder-supported aluminum-based adsorbent according to an embodiment of the present invention.

[0027] Reference Figure 1 In the synthesis operation S1, a first solution is prepared using soluble aluminum salt and lithium salt.

[0028] Specifically, a first solution is prepared by dissolving soluble aluminum salts and lithium salts in 200–300 mL of deionized water. The molar ratio of aluminum ions in the soluble aluminum salt to lithium ions in the lithium salt is (0.1–1):(0.1–1). Furthermore, in the first solution, the aluminum ion concentration of the soluble aluminum salt is 0.1–10 mol / L, and the lithium ion concentration of the lithium salt is 0.1–10 mol / L.

[0029] In one example, the soluble aluminum salt includes at least one of anhydrous aluminum chloride, aluminum chloride hexahydrate, aluminum sulfate, hydrated aluminum sulfate, aluminum nitrate, hydrated aluminum nitrate, aluminum silicate, and aluminum sulfide.

[0030] In one example, the lithium salt includes at least one of anhydrous lithium chloride, hydrated lithium chloride, anhydrous lithium hydroxide, hydrated lithium hydroxide, lithium carbonate, lithium acetate, and lithium nitrate.

[0031] Continue to refer to Figure 1 In synthesis operation S2, a mixed solution of alkaline solution and soluble polymer solution is prepared.

[0032] Specifically, firstly, a soluble alkali is dissolved in deionized water to obtain a second solution. The alkali concentration in the second solution is 0.5–5 mol / L.

[0033] Next, the soluble polymer is dissolved in deionized water to obtain a third solution. The concentration of the soluble polymer in the third solution is 0.1–1 mol / L.

[0034] Next, the second and third solutions are mixed to obtain a fourth solution, which is a mixture of an alkaline solution and a soluble polymer solution.

[0035] In one example, the soluble base is at least one of sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, ammonia, and urea.

[0036] In one example, the soluble polymer is at least one of polypropylene glycol, polyethylene oxide, polyethylene glycol-600, polyethylene glycol-1000, and polyethylene glycol-2000.

[0037] Continue to refer to Figure 1 In synthesis operation S3, the fourth solution is added to the first solution, and its pH value is adjusted to a preset range, and a mixture is obtained by reaction.

[0038] Specifically, the fourth solution is added dropwise to the first solution at a rate of 5–60 mL / min, stirred until homogeneous, and the pH value is adjusted to 6.0–8.0. The mixture is then reacted for 10–20 min to obtain the final product.

[0039] Continue to refer to Figure 1 In synthesis operation S4, the mixture is washed, filtered, and dried to obtain aluminum-based adsorbent precursor powder.

[0040] Continue to refer to Figure 1 In synthesis operation S5, the aluminum-based adsorbent precursor powder is granulated to obtain aluminum-based adsorbent particles.

[0041] Specifically, firstly, an organic solvent, an organic polymer, and an aluminum-based adsorbent precursor powder are mixed to form a slurry. The organic solvent, organic polymer, and aluminum-based adsorbent precursor powder are mixed in a mass ratio of (1–20):(0.1–2):(1–10) to form a homogeneous slurry.

[0042] Next, the slurry is dripped into a flowing inorganic solvent to solidify and form aluminum-based adsorbent particles. Specifically, at least one of a pinhole, a micro-injection pump, and a centrifugal granulation microfluidic dripper is used to drip the slurry into flowing deionized water at a constant rate to solidify and form particles with a diameter of 2–3 mm.

[0043] The specific synthetic embodiments will be described in detail below. These specific synthetic embodiments employ... Figure 1 The preparation method shown.

[0044] <Specific Synthesis Example 1>

[0045] First, weigh out sodium hydroxide, polyethylene glycol-600, aluminum chloride hexahydrate, and lithium chloride according to the molar ratio of Na:PEG:Al:Li of 3.3:0.2:1:0.5.

[0046] Next, aluminum chloride hexahydrate and lithium chloride are dissolved in deionized water to obtain the first solution. In the first solution, the concentration of aluminum ions is 0.1–10 mol / L and the concentration of lithium ions is 0.1–10 mol / L.

[0047] Next, sodium hydroxide is dissolved in pure water to obtain a second solution. In the second solution, the alkali concentration is 0.5–5 mol / L.

[0048] Next, polyethylene glycol-600 was dissolved in pure water to obtain a third solution.

[0049] Next, the second solution is mixed with the third solution to obtain the fourth solution.

[0050] Next, the fourth solution was added dropwise to the first solution containing aluminum chloride hexahydrate and lithium chloride, the pH of the solution was adjusted to 7.5, and the mixture was stirred at 45°C for 10 minutes to form a mixture. The mixture was then washed, filtered, and dried to obtain aluminum-based adsorbent precursor powder.

[0051] Next, 2.5g of polyvinyl chloride and 0.5g of polyacrylonitrile were dissolved in 50mL of dimethylformamide and stirred evenly at 27°C to form an organic polymer solution. 20g of aluminum-based adsorbent precursor powder was then dissolved in the organic polymer solution to form a slurry.

[0052] Next, after stirring the slurry for 10 minutes, it was dripped into slowly flowing deionized water using a 9×15mm needle to solidify it into aluminum-based adsorbent particles with a particle diameter of 2-3mm and a powder loading of 87%.

[0053] Finally, 1.6 g of aluminum-based adsorbent particles were mixed with 100 mL of deionized water, and the mixture was shaken and deintercalated in a constant temperature shaker for 2 hours. After filtration and drying, aluminum-based adsorbent particles were obtained. The filtered and dried aluminum-based adsorbent particles were then mixed with water containing 600 ppm Li + The solution with an initial lithium ion concentration in sulfate-type brine was mixed and adsorbed by shaking in a constant temperature shaker. The adsorption capacity was >9 mg / g, which is much higher than that of adsorbent particles in the same industry.

[0054] Figure 2This is an adsorption curve of the high powder-loaded aluminum adsorbent prepared in the first specific synthesis example.

[0055] Reference Figure 2 This high-powder-loaded aluminum-based adsorbent particle has a high adsorbent powder content, a fast adsorption rate, and high particle permeability. Therefore, it is suitable for industrial column packing operations.

[0056] Figure 3 This is a schematic diagram of the high powder-loaded aluminum adsorbent prepared in the first specific synthesis example after 10 adsorption cycles.

[0057] Reference Figure 3 After 10 adsorption cycles, the adsorption capacity of the highly powdered aluminum-based adsorbent particles can be stabilized at a relatively high adsorption capacity level of approximately 9 mg / g.

[0058] <Specific Synthesis Example 2>

[0059] Weigh sodium hydroxide, polyethylene glycol-600, aluminum chloride hexahydrate, and lithium chloride according to the molar ratio of Na:PEG:Al:Li of 3.3:0.2:1:0.5.

[0060] Aluminum chloride hexahydrate and lithium chloride were dissolved in deionized water to obtain the first solution. In the first solution, the concentration of aluminum ions was 0.1–10 mol / L and the concentration of lithium ions was 0.1–10 mol / L.

[0061] Sodium hydroxide is dissolved in pure water to obtain a second solution. The alkali concentration of the second solution is 0.5–5 mol / L.

[0062] Polyethylene glycol was dissolved in pure water to obtain a third solution.

[0063] The second solution is mixed with the third solution to obtain the fourth solution.

[0064] The fourth solution was added dropwise to the first solution containing aluminum chloride hexahydrate and lithium chloride, the pH of the solution was adjusted to 7.5, and the mixture was stirred at 45°C for 10 min to obtain a mixture. The mixture was then washed, filtered, and dried to obtain aluminum-based adsorbent precursor powder.

[0065] 2.5g of polyvinyl chloride and 0.5g of polyacrylonitrile were dissolved in 50mL of dimethylformamide and stirred evenly at 27℃ to form an organic polymer solution. 15g, 20g and 25g of adsorbent powder were dissolved in the organic polymer solution to form slurries.

[0066] After stirring the slurry for 10 minutes, use a 9×15mm needle to drip it into slowly flowing deionized water to solidify it into particles.

[0067] Figure 4 This is a comparison diagram of the powder loading of various high powder-loaded aluminum adsorbent particles prepared in the specific synthesis example 2.

[0068] Reference Figure 4 The 15g and 20g adsorbent powder loaded particles were clean and orderly in appearance, covered by a smooth film, and showed no powder leakage during subsequent use. However, the 15g powder load was relatively low and did not achieve the expected effect. Slight powder shedding was observed in the 25g powder load, which was not conducive to subsequent experiments.

[0069] <Specific Synthesis Example 3>

[0070] Weigh sodium hydroxide, polyethylene glycol-600, aluminum chloride hexahydrate, and lithium chloride according to the molar ratio of Na:PEG:Al:Li of 3.3:0.2:1:0.5.

[0071] Aluminum chloride hexahydrate and lithium chloride were dissolved in deionized water to obtain the first solution. The concentration of aluminum ions in the first solution was 0.1–10 mol / L, and the concentration of lithium ions was 0.1–10 mol / L.

[0072] Sodium hydroxide is dissolved in pure water to obtain a second solution. The alkali concentration of the second solution is 0.5–5 mol / L.

[0073] Polyethylene glycol was dissolved in pure water to obtain a third solution.

[0074] The second solution is mixed with the third solution to obtain the fourth solution.

[0075] The fourth solution was added dropwise to the first solution containing aluminum chloride hexahydrate and lithium chloride, the pH of the solution was adjusted to 7.5, and the mixture was stirred at 45°C for 10 min to obtain a mixture. The mixture was then washed, filtered, and dried to obtain aluminum-based adsorbent precursor powder.

[0076] Dissolve 2.5g of polyvinyl chloride and 0.5g of polyacrylonitrile in 50mL of dimethylformamide and stir evenly at 27℃ to form an organic polymer solution. Dissolve 15g, 20g, and 25g of adsorbent powder in the organic polymer solution to form slurries.

[0077] After stirring the slurry for 10 minutes, use a 9×15mm needle to drip it into slowly flowing deionized water to solidify it into particles.

[0078] Figure 5 These are comparative scanning electron microscope cross-sectional images of the high powder-loaded aluminum adsorbent particles prepared in the specific synthesis example three.

[0079] Reference Figure 5In the SEM image of the cross-section of the 20g powder-loaded aluminum adsorbent particles, the morphology of the aluminum adsorbent particles can be seen. A large number of hollow porous structures can be seen inside the particles, which provide structural support for the whole. The network structure formed by the boundary binder can also be seen, which effectively reduces powder agglomeration and reduces the number of closed pores.

[0080] In summary, according to embodiments of the present invention, a soluble polymer is added to an alkaline solution and then mixed with a soluble lithium salt. The aluminum salt mixture is then used to prepare aluminum-based adsorbent precursor powder via a simple precipitation and intercalation reaction. During solvent-resistant extrusion granulation, the functional groups inherent in the soluble polymer effectively reduce powder agglomeration and powder shedding during use. Under the same binder ratio, the powder loading is more than twice that of ordinary aluminum-based adsorbent powder, effectively reducing the use of organic polymers and lowering costs. Furthermore, compared to aluminum-based adsorbent particles prepared by other methods, embodiments of the present invention show a powder loading rate of 87%, and the adsorption rate reaches equilibrium in a shorter time, even with 600 ppm Li. + In sulfate-type brine, the adsorption capacity is >9 mg / g. Furthermore, it can be directly applied to extract Li from raw brine and aged brine. + It can rapidly adsorb a large number of lithium ions in a short period of time, achieving efficient separation and extraction. Furthermore, the aluminum-based adsorbent particles according to embodiments of the present invention exhibit high stability, maintaining a certain adsorption level during 10 cycles of use without dissolution, demonstrating good structural stability.

[0081] Therefore, the embodiments of the present invention have advantages such as high powder loading, fast adsorption rate, high adsorption capacity, stability and reliability, and reusability. In the field of lithium extraction from liquid-phase salt lakes, they can be directly applied to Li in raw brine and old brine. + Extraction has high practical application and promotion value.

[0082] The optional embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the scope of the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all fall within the protection scope of the embodiments of the present invention.

Claims

1. A method for preparing a high-powder-supported aluminum-based adsorbent, characterized in that, The preparation method includes the following steps: The first solution was prepared using soluble aluminum and lithium salts; A second solution is prepared using a soluble base; A third solution was prepared using a soluble polymer; The second solution and the third solution are mixed to obtain a fourth solution; The fourth solution is added to the first solution, and its pH value is adjusted to a preset range, and a mixture is obtained by reaction; The mixture is washed, filtered, and dried to obtain aluminum-based adsorbent precursor powder; The aluminum-based adsorbent precursor powder was granulated to obtain aluminum-based adsorbent particles.

2. The preparation method according to claim 1, characterized in that, The method for granulating aluminum-based adsorbent precursor powder includes: Organic solvents, organic polymers, and aluminum-based adsorbent precursor powders are mixed to form a slurry; The slurry is dropped into a flowing inorganic solvent to solidify and form aluminum-based adsorbent particles.

3. The preparation method according to claim 2, characterized in that, The mass ratio of the organic solvent, the organic polymer, and the aluminum-based adsorbent precursor powder is (1-20):(0.1-2):(1-10).

4. The preparation method according to any one of claims 1 to 3, characterized in that, The preset range is 6.0 to 8.

0.

5. The preparation method according to any one of claims 1 to 3, characterized in that, The soluble aluminum salt is at least one of anhydrous aluminum chloride, aluminum chloride hexahydrate, aluminum sulfate, hydrated aluminum sulfate, aluminum nitrate, hydrated aluminum nitrate, aluminum silicate, and aluminum sulfide; wherein the aluminum ion concentration of the soluble aluminum salt in the first solution is 0.1–10 mol / L.

6. The preparation method according to any one of claims 1 to 3, characterized in that, The lithium salt is at least one of anhydrous lithium chloride, hydrated lithium chloride, anhydrous lithium hydroxide, hydrated lithium hydroxide, lithium carbonate, lithium acetate, and lithium nitrate; wherein the lithium ion concentration of the lithium salt in the first solution is 0.1–10 mol / L.

7. The preparation method according to any one of claims 1 to 3, characterized in that, The soluble alkali is at least one of sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, ammonia, and urea; and / or, the alkali concentration of the second solution is 0.5–5 mol / L.

8. The preparation method according to any one of claims 1 to 3, characterized in that, The soluble polymer is at least one of polypropylene glycol, polyethylene oxide, polyethylene glycol-600, polyethylene glycol-1000, and polyethylene glycol-2000, and / or the concentration of the soluble polymer in the third solution is 0.1 to 1 mol / L.

9. The preparation method according to claim 2 or 3, characterized in that, The organic polymer is at least one of polyacrylonitrile, polyvinyl alcohol, polyvinyl chloride, polyvinyl fluoride, and polyacrylamide; and / or the organic solvent is at least one of N-methylpyrrolidone, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, and tetrahydrofuran.

10. An aluminum-based adsorbent, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 9.

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