A method for preparing an intercalated self-assembled aluminum-based lithium adsorbent

Abstract

This invention discloses a method for preparing an intercalated self-assembled aluminum-based lithium adsorbent, comprising the following steps: (1) obtaining an aluminum-lithium mixture; (2) obtaining a protonated surfactant solution; (3) adding the protonated surfactant solution dropwise to the aluminum-lithium mixture and stirring until homogeneous; (4) adding an alkaline solution dropwise to the material obtained in step (3); (5) reacting the material obtained in step (4) at 80-120°C to obtain a first product; (6) washing the first product with water and ethanol by vacuum filtration, followed by vacuum drying and grinding to form a second product; (7) granulating the second product to obtain a third product; and (8) crushing and sieving the third product to obtain the final product. This invention prepares an intercalated self-assembled lithium adsorbent powder using a homogeneous-hydrothermal precipitation method. The powder exhibits good crystallinity, and the resulting lithium adsorbent, obtained through binder granulation, has a large adsorption capacity, low solubility, and strong anti-pollution ability.

Description

Technical Field

[0001] This invention belongs to the field of lithium adsorbent technology, specifically relating to a method for preparing an intercalated self-assembled aluminum-based lithium adsorbent. Background Technology

[0002] Lithium, being the most reactive and lightest metal, has become a focus of attention and development. Lithium and its compounds are widely used in metallurgy, aerospace, medicine, chemical engineering, electronics, and defense. With the continuous development and progress of science and technology, the applications of lithium and its compounds are becoming increasingly widespread, and the demand is also growing. While brine lithium resources are abundant, their grade is low. Due to their unique type, high magnesium-to-lithium ratio, and difficulty in separation, the processing technology is still immature. However, with the depletion of solid lithium ore and the development of brine lithium extraction technology, brine lithium extraction will become a key focus for lithium resource extraction.

[0003] Currently, lithium extraction technologies from salt lakes mainly include evaporation concentration and precipitation, calcination leaching, solvent extraction, membrane separation, salting out, and adsorption. Membrane separation is widely studied due to its high selectivity for lithium ions, stable adsorption and desorption performance, simple preparation method, good thermal and mechanical stability, moderate price, good cycle performance, and no environmental pollution. Common lithium adsorbents used in adsorption methods for lithium extraction from salt lake brine include manganese-based ion sieves, titanium-based ion sieves, and aluminum-based lithium adsorbents. Manganese and titanium-based ion sieves have high adsorption capacity and ultra-high selectivity, but their desorption and extraction require acid washing, which causes dissolution and internal structural collapse, preventing repeated recycling and limiting their application. Aluminum-based lithium adsorbents, on the other hand, can be desorbed and regenerated simply by washing with water, preventing damage to equipment and the environment from large amounts of acid. However, current aluminum-based lithium adsorbents have small interlayer spacing in their layered structure, resulting in low effective utilization area and low adsorption capacity. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects of the prior art and provide a method for preparing an intercalated self-assembled aluminum-based lithium adsorbent.

[0005] The technical solution of the present invention is as follows:

[0006] A method for preparing an intercalated self-assembled aluminum-based lithium adsorbent includes the following steps:

[0007] (1) Soluble aluminum compound and soluble lithium compound are ultrasonically dissolved in deionized water and reacted at 70-80℃ to obtain aluminum-lithium mixture;

[0008] (2) Protonate the surfactant with concentrated hydrochloric acid to obtain a protonated surfactant solution;

[0009] (3) At a rotation speed of 1800-2000 r / min and a temperature of 70-80℃, the above protonated surfactant solution was added dropwise to the above aluminum-lithium mixture and stirred until homogeneous.

[0010] (4) Add the alkaline solution dropwise to the material obtained in step (3), and control the pH value at the endpoint of the dropwise addition to 6;

[0011] (5) React the material obtained in step (4) at 80-120℃ for 4-10h to obtain the first product;

[0012] (6) The first product above is washed with water and ethanol by vacuum filtration to remove unreacted ions, then vacuum dried until the water content is less than 5%, and then ground and pulverized to form the second product;

[0013] (7) The second product is added to a conical double helix mixer, then binder and solvent are added, and the third product is obtained by mixing and granulation.

[0014] (8) The third product is crushed and sieved to obtain the intercalated self-assembled aluminum-based lithium adsorbent with a particle size of 0.4-1.5 mm.

[0015] In a preferred embodiment of the present invention, the soluble aluminum compound is at least one of aluminum chloride, aluminum sulfate, and aluminum nitrate.

[0016] In a preferred embodiment of the present invention, the soluble lithium compound is at least one of lithium hydroxide, lithium chloride, and lithium carbonate.

[0017] In a preferred embodiment of the present invention, the surfactant is at least one selected from hexadecyltrimethylammonium bromide, sodium dodecyl sulfate, and hexadecyltrimethylammonium chloride.

[0018] In a preferred embodiment of the invention, the adhesive is at least one of polyvinyl alcohol, polyurethane, and epoxy resin.

[0019] In a preferred embodiment of the present invention, the alkaline solution is a sodium hydroxide solution or a potassium hydroxide solution.

[0020] In a preferred embodiment of the present invention, the solvent is at least one selected from water, ethanol, acetone and ethyl acetate.

[0021] In a preferred embodiment of the present invention, in step (1), the molar ratio of surfactant, Al and Li is 1-2:2:1.

[0022] More preferably, in step (4), the amount of the adhesive is 20 wt% of the second product.

[0023] More preferably, in step (4), the amount of solvent is 50 wt% of the second product.

[0024] The beneficial effects of this invention are: This invention prepares intercalated self-assembled lithium adsorbent powder by homogeneous-hydrothermal precipitation method. The powder has good crystallinity. The lithium adsorbent obtained by granulation with binder has a large adsorption capacity, low solubility, strong anti-pollution ability, and an adsorption capacity of 5-7 mg / L. It still maintains a high adsorption capacity after 100 regeneration cycles. Attached Figure Description

[0025] Figure 1 The images show the XRD patterns of the intercalated self-assembled aluminum-based lithium adsorbents prepared in the comparative examples and embodiments of this invention.

[0026] Figure 2 This is a scanning electron microscope image of the intercalated self-assembled aluminum-based lithium adsorbent prepared in Example 2 of the present invention. Detailed Implementation

[0027] The technical solution of the present invention will be further explained and described below with reference to specific embodiments and accompanying drawings.

[0028] Comparative Example 1

[0029] (1) Weigh 36g AlCl3·6H2O and 4.5g LiCl·H2O and dissolve them in 100mL of deionized water (Li / Al molar ratio is 1 / 2). After sonicating for 60min and mixing evenly, react in a water bath at 75℃ for 2h to obtain an aluminum-lithium mixture.

[0030] (2) 5 mol / L sodium hydroxide was added dropwise to the above aluminum-lithium mixture at a rate of 10 mL / min. The pH value at the endpoint of the addition was controlled to be 6, and the first product was obtained.

[0031] (3) The first product above is washed with water and ethanol by vacuum filtration to remove unreacted ions, then vacuum dried at 120°C for 12 hours until the water content is less than 5%, and then ground to form the second product.

[0032] (4) The second product is added to a conical double helix mixer, followed by 20% polyurethane resin and 50% anhydrous ethanol by mass of the second product, and the third product is obtained by mixing and granulation.

[0033] (5) The third product above is crushed and screened to obtain a comparative lithium adsorbent with a particle size of 0.4-1.5 mm.

[0034] The comparative lithium adsorbent prepared in this comparative example was loaded into a 60 mL adsorption column and activated by washing with water. Salt lake brine (initially with a Li concentration of 300 ppm, taken from a salt lake in Qinghai) was fed through the adsorption column at a feed rate of 2 BV / h. The change in Li+ in the adsorption tail liquid of the old brine was measured by ICP. After adsorption saturation, the working capacity was 2.8 mg / L. After 100 cycles of analysis and regeneration, the working capacity was 2.13 mg / L.

[0035] Comparative Example 2

[0036] (1) Weigh 36g AlCl3·6H2O and 4.5g LiCl·H2O and dissolve them in 100mL of deionized water (Li / Al molar ratio is 1 / 2). After sonicating for 60min and mixing evenly, react in a water bath at 75℃ for 2h to obtain an aluminum-lithium mixture.

[0037] (2) Add 35g of urea to the above aluminum-lithium mixture, then pour it into the reaction vessel, set the temperature to 80℃, and the reaction time to 4h to obtain the first product.

[0038] (3) The first product above is washed with water and ethanol by vacuum filtration to remove unreacted ions, then vacuum dried at 120°C for 12 hours until the water content is less than 5%, and then ground to form the second product.

[0039] (4) The second product is added to a conical double helix mixer, followed by 20% polyurethane resin and 50% anhydrous ethanol by mass of the second product, and the third product is obtained by mixing and granulation.

[0040] (5) The third product above is crushed and screened to obtain a comparative lithium adsorbent with a particle size of 0.4-1.5 mm.

[0041] The comparative lithium adsorbent prepared in this comparative example was loaded into a 60 mL adsorption column and activated by washing with water. Salt lake brine (initially with a Li concentration of 300 ppm, taken from a salt lake in Qinghai) was fed through the adsorption column at a feed rate of 2 BV / h. The change in Li+ in the adsorption tail liquid of the old brine was measured by ICP. After adsorption saturation, the working capacity was 3.82 mg / L. After 100 cycles of analysis and regeneration, the working capacity was 3.45 mg / L.

[0042] Comparative Example 3

[0043] (1) Weigh 36g AlCl3·6H2O and 4.5g LiCl·H2O and dissolve them in 100mL of deionized water. The Li / Al molar ratio is 1 / 2. After sonicating for 60min and mixing evenly, react in a water bath at 75℃ for 2h to obtain an aluminum-lithium mixture.

[0044] (2) Mix 15g of CTAB and concentrated hydrochloric acid at a volume ratio of 1:2 to form a CTAB protonated solution;

[0045] (3) At a rotation speed of 2000 r / min and a temperature of 75°C, the CTAB protonation solution was added dropwise to the above aluminum-lithium mixture and stirred until homogeneous;

[0046] (4) Add 5 mol / L sodium hydroxide to the material obtained in step (3) at a dropping rate of 10 mL / min, and control the pH value at the endpoint of the dropping to 6.

[0047] (5) Pour the material obtained in step (4) into the reactor, set the temperature to 80°C, and the reaction time to 4h to obtain the first product;

[0048] (6) The first product above is washed with water and ethanol by vacuum filtration to remove unreacted ions, then vacuum dried at 120°C for 12 hours until the water content is less than 5%, and then ground to form the second product.

[0049] (7) The second product is added to a conical double helix mixer, followed by 20% polyurethane resin and 50% anhydrous ethanol by mass of the second product, and the third product is obtained by mixing and granulation.

[0050] (8) The third product above is crushed and screened to obtain a comparative lithium adsorbent with a particle size of 0.4-1.5 mm.

[0051] The comparative lithium adsorbent prepared in this comparative example was loaded into a 60 mL adsorption column and activated by washing with water. Salt lake brine (initially with a Li concentration of 300 ppm, taken from a salt lake in Qinghai) was fed through the adsorption column at a feed rate of 2 BV / h. The change in Li+ in the adsorption tail liquid of the old brine was measured by ICP. After adsorption saturation, the working capacity was 4.2 mg / L. After 100 cycles of analysis, recycling and regeneration, the working capacity was 3.78 mg / L.

[0052] Example 1

[0053] (1) Weigh 36g AlCl3·6H2O and 4.5g LiCl·H2O and dissolve them in 100mL of deionized water (Li / Al molar ratio is 1 / 2). After sonicating for 60min and mixing evenly, react in a water bath at 75℃ for 2h to obtain an aluminum-lithium mixture.

[0054] (2) Mix 27.3g of CTAB and concentrated hydrochloric acid at a volume ratio of 1:2 to form a protonated solution of CTAB;

[0055] (3) At a rotation speed of 2000 r / min and a temperature of 75°C, the above CTAB protonated solution was added dropwise to the above aluminum-lithium mixture and stirred until homogeneous;

[0056] (4) Add 5 mol / L sodium hydroxide to the material obtained in step (3) at a dropping rate of 10 mL / min, and control the pH value at the endpoint of the dropping to 6.

[0057] (5) Pour the material obtained in step (4) into the reactor, set the temperature to 80°C, and the reaction time to 4h to obtain the first product;

[0058] (6) The first product above is washed with water and ethanol by vacuum filtration to remove unreacted ions, then vacuum dried at 120°C for 12 hours until the water content is less than 5%, and then ground to form the second product.

[0059] (7) The second product is added to a conical double helix mixer, followed by 20% polyurethane resin and 50% anhydrous ethanol by mass of the second product, and the third product is obtained by mixing and granulation.

[0060] (8) The above third product is crushed and sieved to obtain the following: Figure 1 The intercalated self-assembled aluminum-based lithium adsorbent shown has a particle size of 0.4-1.5 mm.

[0061] The intercalated self-assembled aluminum-based lithium adsorbent prepared in this embodiment was loaded into a 60 mL adsorption column and activated by washing with water. Salt lake brine (initially with a Li concentration of 300 ppm, taken from a salt lake in Qinghai) was fed through the adsorption column at a feed rate of 2 BV / h. The change in Li+ in the adsorption tail liquid of the old brine was measured by ICP. After adsorption saturation, the working capacity was 5.72 mg / L. After 100 cycles of analysis, recycling and regeneration, the working capacity was 5.42 mg / L.

[0062] Example 2

[0063] (1) Weigh 36g AlCl3·6H2O and 4.5g LiCl·H2O and dissolve them in 100mL of deionized water (Li / Al molar ratio is 1 / 2). After sonicating for 60min and mixing evenly, react in a water bath at 75℃ for 2h to obtain an aluminum-lithium mixture.

[0064] (2) Mix 41g of CTAB and concentrated hydrochloric acid at a volume ratio of 1:2 to form a CTAB protonated solution;

[0065] (3) At a rotation speed of 2000 r / min and a temperature of 75°C, the above CTAB protonated solution was added dropwise to the above aluminum-lithium mixture and stirred until homogeneous;

[0066] (4) Add 5 mol / L sodium hydroxide to the material obtained in step (3) at a dropping rate of 10 mL / min, and control the pH value at the endpoint of the dropping to 6.

[0067] (5) Pour the material obtained in step (4) into the reactor, set the temperature to 80°C, and the reaction time to 4h to obtain the first product;

[0068] (6) The first product above is washed with water and ethanol by vacuum filtration to remove unreacted ions, then vacuum dried at 120°C for 12 hours until the water content is less than 5%, and then ground to form the second product.

[0069] (7) The second product is added to a conical double helix mixer, followed by 20% polyurethane resin and 50% anhydrous ethanol by mass of the second product, and the third product is obtained by mixing and granulation.

[0070] (8) The above third product is crushed and sieved to obtain the following: Figure 1 and Figure 2 The intercalated self-assembled aluminum-based lithium adsorbent shown has a particle size of 0.4-1.5 mm.

[0071] The intercalated self-assembled aluminum-based lithium adsorbent prepared in this embodiment was loaded into a 60 mL adsorption column and activated by washing with water. Salt lake brine (initially with a Li concentration of 300 ppm, taken from a salt lake in Qinghai) was fed through the adsorption column at a feed rate of 2 BV / h. The change in Li+ in the adsorption tail liquid of the old brine was measured by ICP. After adsorption saturation, the working capacity was 6.92 mg / L. After 100 cycles of analysis, recycling and regeneration, the working capacity was 6.68 mg / L.

[0072] Example 3

[0073] (1) Weigh 36g AlCl3·6H2O and 4.5g LiCl·H2O and dissolve them in 100mL of deionized water (Li / Al molar ratio is 1 / 2). After sonicating for 60min and mixing evenly, react in a water bath at 75℃ for 2h to obtain an aluminum-lithium mixture.

[0074] (2) Mix 54.3g of CTAB and concentrated hydrochloric acid at a volume ratio of 1:2 to form a CTAB protonated solution;

[0075] (3) At a rotation speed of 2000 r / min and a temperature of 75°C, the above CTAB protonated solution was added dropwise to the above aluminum-lithium mixture and stirred until homogeneous;

[0076] (4) Add 5 mol / L sodium hydroxide to the material obtained in step (3) at a dropping rate of 10 mL / min, and control the pH value at the endpoint of the dropping to 6.

[0077] (5) Pour the material obtained in step (4) into the reactor, set the temperature to 80°C, and the reaction time to 4h to obtain the first product;

[0078] (6) The first product above is washed with water and ethanol by vacuum filtration to remove unreacted ions, then vacuum dried at 120°C for 12 hours until the water content is less than 5%, and then ground to form the second product.

[0079] (7) The second product is added to a conical double helix mixer, followed by 20% polyurethane resin and 50% anhydrous ethanol by mass of the second product, and the third product is obtained by mixing and granulation.

[0080] (8) The above third product is crushed and sieved to obtain the following: Figure 1 The intercalated self-assembled aluminum-based lithium adsorbent shown has a particle size of 0.4-1.5 mm.

[0081] The intercalated self-assembled aluminum-based lithium adsorbent prepared in this embodiment was loaded into a 60 mL adsorption column and activated by washing with water. Salt lake brine (initially with a Li concentration of 300 ppm, taken from a salt lake in Qinghai) was fed through the adsorption column at a feed rate of 2 BV / h. The change in Li+ in the adsorption tail liquid of the old brine was measured by ICP. After adsorption saturation, the working capacity was 6.6 mg / L. After 100 cycles of analysis, recycling and regeneration, the working capacity was 6.26 mg / L.

[0082] Table 1 Performance parameters of the adsorbents prepared in the examples and comparative examples

[0083]

[0084]

[0085] 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 intercalated self-assembled aluminum-based lithium adsorbent, characterized by: Includes the following steps: (1) Dissolve a soluble aluminum compound and a soluble lithium compound in deionized water by ultrasonication, and react at 70-80℃ to obtain an aluminum-lithium mixture; the soluble aluminum compound is at least one of aluminum chloride, aluminum sulfate and aluminum nitrate, and the soluble lithium compound is at least one of lithium hydroxide, lithium chloride and lithium carbonate. (2) Hexadecyltrimethylammonium bromide (CTAB) and concentrated hydrochloric acid were stirred at a volume ratio of 1:2 to form a protonated CTAB solution; (3) At a rotation speed of 1800-2000 r / min and a temperature of 70-80℃, the above CTAB protonation solution was added dropwise to the above aluminum-lithium mixture and stirred evenly. The molar ratio of surfactant, Al and Li was 1-2: 2:

1. (4) Add the alkaline solution dropwise to the material obtained in step (3), and control the pH value at the endpoint of the addition to 6; the alkaline solution is a sodium hydroxide solution or a potassium hydroxide solution; (5) React the material obtained in step (4) at 80-120℃ for 4-10h to obtain the first product; (6) The first product above is washed with water and ethanol by vacuum filtration to remove unreacted ions, then vacuum dried until the water content is less than 5%, and then ground to form the second product; (7) The second product is added to a conical double helix mixer, then a binder and a solvent are added, and the third product is obtained by mixing and granulation; the binder is at least one of polyvinyl alcohol, polyurethane and epoxy resin, and the solvent is at least one of water, ethanol, acetone and ethyl acetate; (8) The third product above is crushed and sieved to obtain the intercalated self-assembled aluminum-based lithium adsorbent with a particle size of 0.4-1.5 mm.

2. The preparation method according to claim 1, characterized in that: In step (7), the amount of adhesive is 20 wt% of the second product.

3. The preparation method according to claim 2, characterized in that: In step (7), the amount of solvent is 50 wt% of the second product.

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