A high-temperature lithium extraction adsorbent, its preparation method and application

Abstract

The present invention relates to an adsorbent for lithium extraction, its preparation method and application, belonging to the field of material technology. First, a precursor solution is prepared; then, a spinel-type lithium magnesium aluminum oxide is prepared; finally, an adsorbent for high-temperature lithium extraction is obtained. The adsorbent of the present invention can achieve efficient adsorption of lithium ions in geothermal fluid. At about 80 °C, the saturated adsorption capacity of this adsorbent for Li + is greater than 40 mg / g, and the saturated adsorption capacity is greater than 35 mg / g after 30 cycles of reuse.

Description

Technical Field

[0001] The present invention relates to an adsorbent for lithium extraction at high temperature, its preparation method and application, belonging to the technical field of materials. Background Art

[0002] With the sharp increase in global demand for lithium, traditional lithium extraction methods have been difficult to meet market demand. Therefore, it is particularly important to explore new ways to extract lithium resources. Geothermal fluids are rich in lithium elements, and geothermal resources are widely distributed globally, which provides great potential for the development of lithium extraction technology from geothermal fluids. The research on lithium extraction technology from geothermal fluids not only helps to alleviate the contradiction between supply and demand of lithium resources, but also can effectively utilize geothermal resources to achieve the dual utilization of energy and mineral resources. This multiple utilization mode not only enhances the economic value of geothermal resources, but also provides new ideas for the sustainable development of lithium resources. As an efficient lithium extraction material, adsorbents have gradually become a research hotspot due to their advantages such as good selectivity, large adsorption capacity and easy regeneration.

[0003] Patent 202211737926.X reported a preparation method of a Li2TiO3 lithium extraction adsorbent, which achieved the characteristics of low titanium dissolution rate and good structural stability of the adsorbent by adding lithium sources step by step, and had a high Li + adsorption capacity during the lithium extraction process from brines at room temperature. Patent 202411338415.X reported a LiAl-LDHs@Al-MOFs core-shell lithium extraction adsorbent, which achieved high-selectivity lithium extraction from brines with a high magnesium-lithium ratio at room temperature and had good cyclic use stability.

[0004] However, compared with lithium extraction technology from brines, lithium extraction technology from geothermal fluids requires high-selectivity adsorption of Li + at high temperature. Currently, existing lithium extraction adsorbents all have problems such as low Li + adsorption capacity at high temperature and insufficient stability of the adsorbent in the lithium extraction environment under high-temperature and high-pressure conditions. The research on lithium extraction technology from geothermal fluids is still in its infancy, and there are no relevant reports on special adsorbents for lithium extraction from geothermal fluids. Therefore, it is of great significance to develop efficient adsorbents for extracting lithium from geothermal fluids. Summary of the Invention

[0005] The object of the present invention is, in view of the above situation, to provide an adsorbent for lithium extraction at high temperature, its preparation method and application. The adsorbent is a spinel-type magnesium-aluminum oxide lithium ion sieve, which can achieve efficient adsorption of lithium ions in geothermal fluids. At about 60-80 °C, the saturated Li + adsorption capacity of the adsorbent is greater than 40 mg / g, and after 30 cycles of use, the saturated adsorption capacity is greater than 35 mg / g, and it can still achieve efficient adsorption of lithium ions.

[0006] Meanwhile, the present invention provides a preparation method of an adsorbent for lithium extraction at high temperature, which realizes the efficient adsorption of lithium ions through the memory effect, the coordination effect between the adsorbent and Li + and improves the lithium ion selectivity in the process of lithium extraction at high temperature.

[0007] To solve the above technical problems, the present invention adopts the following technical solutions:

[0008] A preparation method of an adsorbent for lithium extraction at high temperature, comprising the following steps:

[0009] Step 1, at room temperature, an aluminum source, a magnesium source, a lithium source, an organic ligand, an acid source and deionized water are sequentially added into a reaction kettle. After stirring at 30-50°C for 0.5-2 h, a precursor solution is obtained; the aluminum source and the magnesium source are fluorine-containing salts or chlorine-containing salts;

[0010] Step 2, at room temperature, the pore-forming agent is prepared into a N,N-dimethylformamide solution with a concentration of 0.05-0.15 mol / L (preferably 0.1 mol / L) (that is, the pore-forming agent is dissolved in the N,N-dimethylformamide solvent to form a N,N-dimethylformamide solution with a pore-forming agent concentration of 0.05-0.15 mol / L. The solubility of the pore-forming agent in the system is increased by the solvent). The pore-forming agent solution is added dropwise to the precursor solution prepared in Step 1. After ultrasonic stirring for 1-2 h, an alkali solution is added dropwise under the ultrasonic stirring state to adjust the pH of the solution to neutral. Then, it is stirred in a constant temperature water bath at 60-90°C for 2-5 h, and then subjected to a crystallization reaction at 180-220°C for 3-8 h (the crystallization reaction is used to form a uniform aluminum-magnesium-lithium skeleton structure, thereby forming a more stable lithium-magnesium-aluminum spinel). After filtration, washing with the solvent, drying at 140-160°C for 10-24 h, and then calcining at 1200-1500°C for 10-24 h, a spinel-type lithium-magnesium-aluminum oxide is obtained;

[0011] Step 3, at room temperature, the spinel-type lithium-magnesium-aluminum oxide prepared in Step 2 and an acidic solution are added into a reaction kettle. After constant temperature oscillation for 2-5 h, filtration, washing, drying at 80-120°C for 10-24 h, and then calcining at 1200-1500°C for 10-24 h, an adsorbent for lithium extraction at high temperature is obtained.

[0012] In Step 1, the aluminum source is sodium hexafluoroaluminate or aluminum chloride; the magnesium source is magnesium fluoride or magnesium chloride; the lithium source is lithium hydroxide or lithium nitrate; the organic ligand is 2,2'-bipyridine or 2-methylimidazole; the acid source is nitric acid or hydrochloric acid.

[0013] In Step 1, the mass ratio of the aluminum source, the magnesium source, the lithium source, the organic ligand, the acid source and deionized water is 1:(0.7-0.8):(0.1-0.3):(0.4-0.8):(0.1-0.3):(15-30). In the present invention, a specific magnesium-aluminum ratio is beneficial to the formation of a more perfect spinel structure of the adsorbent at high temperature.

[0014] In Step 2, the pore former is polyethylene wax or polyvinyl alcohol; the alkaline solution is ammonia water or sodium carbonate solution, and the concentration of the sodium carbonate solution can be 0.01 mol / L.

[0015] In Step 2, the mass ratio of the pore former solution to the precursor solution is (1 - 5):1. If the proportion of the pore former is too small, an effective pore structure cannot be formed in the spinel-type lithium magnesium aluminum oxide, affecting the adsorption and diffusion of lithium ions during the lithium extraction process; if the concentration of the pore former is too high, the structure of the spinel-type lithium magnesium aluminum oxide is prone to collapse during the preparation process of the spinel-type lithium magnesium aluminum oxide.

[0016] In Step 3, the acidic solution is hydrochloric acid or nitric acid with a concentration of 0.1 - 0.5 mol / L.

[0017] In Step 3, the mass ratio of the acidic solution to the spinel-type lithium magnesium aluminum oxide is (600 - 800):1.

[0018] In Steps 1 and 2, the stirring rate is 100 - 500 rpm.

[0019] In Step 2, the ultrasonic stirring power is 1000 - 1500 W, and the temperature is 40 - 60°C.

[0020] In Step 3, the temperature of the constant-temperature oscillation is 30 - 50°C.

[0021] For the adsorbent for high-temperature lithium extraction obtained by the preparation method of the present invention, the Li + saturation adsorption capacity is greater than 40 mg / g, and the saturation adsorption capacity is greater than 35 mg / g after 30 cycles of use.

[0022] The present invention also discloses the application of the aforementioned adsorbent for high-temperature lithium extraction as an adsorbent for lithium extraction from geothermal fluids, as well as the preparation method of the aforementioned adsorbent for high-temperature lithium extraction or the application of the adsorbent for high-temperature lithium extraction in lithium extraction from geothermal fluids.

[0023] The present invention has the following beneficial effects:

[0024] (1) The high-temperature lithium extraction adsorbent prepared by the present invention uses magnesium aluminum spinel as the framework structure. Compared with other types of adsorbents, the magnesium aluminum spinel structure is stable and has good acid and alkali resistance, ensuring the structural stability of the lithium extraction adsorbent during high-temperature lithium extraction and the recycling process.

[0025] (2) During the preparation of the adsorbent for high-temperature lithium extraction in the present invention, a nitrogen-containing organic ligand is introduced. The nitrogen atom in the organic ligand forms a coordination bond with the metal ion, enabling aluminum, magnesium, and lithium to be uniformly dispersed in the spinel-type lithium magnesium aluminum oxide. This improves the density of lithium ion vacancies in the high-temperature lithium extraction adsorbent and the structural uniformity of the magnesium-aluminum spinel type in the high-temperature lithium extraction adsorbent, further enhancing the structural stability of the adsorbent during the high-temperature lithium extraction process. At the same time, the nitrogen atom in the nitrogen-containing organic ligand can cooperate with fluorine or chlorine ions. Fluorine or chlorine easily forms an ionic bond with lithium ions, resulting in the difficulty of lithium ion desorption. The competitive adsorption of nitrogen atoms with fluorine or chlorine effectively weakens the polarity of the ionic bond easily formed by fluorine or chlorine with lithium ions, which is conducive to the desorption of lithium ions after high-temperature lithium extraction by the adsorbent, thus ensuring that the adsorbent for high-temperature lithium extraction still maintains a high adsorption capacity after multiple cycles of use.

[0026] (3) During the high-temperature lithium extraction process, due to the high temperature, the diffusion rate of lithium ions is relatively fast. Therefore, compared with lithium extraction at room temperature, there are problems such as low lithium extraction rate and low adsorption capacity. During the preparation of the adsorbent for high-temperature lithium extraction in the present invention, by introducing a pore-forming agent, the pore volume and specific surface area inside the adsorbent are effectively increased. The larger pore volume is conducive to the formation of a locally concentration-stable lithium ion pool inside the adsorbent during the high-temperature lithium extraction process, further enhancing the adsorption rate of the adsorbent during the high-temperature lithium extraction process; the large specific surface area can effectively improve the mass transfer rate of lithium ions on the surface of the adsorbent and the accessibility of lithium ion vacancies during the high-temperature lithium extraction process, thereby increasing the adsorption rate and adsorption capacity of lithium ions by the adsorbent.

[0027] Due to the formation of a coordination bond between the nitrogen atom in the organic ligand and the metal ion, and the lone pair electrons of the introduced fluorine or chlorine atoms forming a stable coordination structure with lithium ions, combined with the sieving and memory effects of lithium ion vacancies, lithium ions can effectively stay in the pores of the adsorbent at high temperature. Thus, a concentration-stable lithium ion pool is formed in the pores with a larger pore volume, and lithium ions can also effectively stay on the specific surface of the adsorbent and be better adsorbed.

[0028] (4) During the high-temperature lithium extraction process, due to the high temperature, conventional adsorbents have a weak binding force with lithium ions, and the lithium ions adsorbed by the adsorbent are easily desorbed, resulting in a low lithium extraction adsorption capacity. Fluorine or chlorine elements are introduced into the adsorbent for high-temperature lithium extraction prepared in the present invention. During the high-temperature lithium extraction process, on the basis of realizing the adsorption and extraction of lithium ions through the sieving and memory effects of lithium ion vacancies, the lone pair electrons of the introduced fluorine or chlorine atoms can form a stable coordination structure with lithium ions, which can effectively improve the binding force of the adsorbent to lithium ions during the high-temperature lithium extraction process, effectively preventing the adsorbed lithium ions from desorbing and falling off the adsorbent, thereby increasing the adsorption capacity of lithium ions during the high-temperature lithium extraction process. Description of the Drawings

[0029] Figure 1XRD pattern of the adsorbent for high-temperature lithium extraction in Example 1. Detailed implementation mode

[0030] The present invention will be further described in detail below with reference to specific embodiments. The following embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0031] Example 1

[0032] At room temperature, 10 g of sodium hexafluoroaluminate, 7.5 g of magnesium fluoride, 2 g of lithium nitrate, 6 g of 2,2'-bipyridine, 2 g of nitric acid, and 200 g of water were successively added to the reaction kettle. After stirring at 40 °C and 300 rpm for 1 h, a precursor solution was obtained.

[0033] At room temperature, polyvinyl alcohol was prepared into a 0.1 mol / L N,N-dimethylformamide solution (pore-forming agent solution). 600 g of the pore-forming agent solution was gradually added dropwise to the precursor solution. After ultrasonic stirring at 1200 W and 50 °C for 1.5 h, ammonia water was added dropwise under ultrasonic stirring to adjust the pH of the solution to neutral. Then, it was stirred at 80 °C in a constant temperature water bath at 300 rpm for 3 h, crystallized at 200 °C for 5 h, filtered, washed with N,N-dimethylformamide solvent, dried at 150 °C for 12 h, and calcined at 1400 °C for 12 h to obtain spinel-type lithium magnesium aluminum oxide.

[0034] At room temperature, 10 g of spinel-type lithium magnesium aluminum oxide and 6000 g of 0.3 mol / L nitric acid solution were added to the reaction kettle. After constant temperature oscillation at 40 °C for 3 h, it was filtered, washed, dried at 100 °C for 12 h, and then calcined at 1400 °C for 12 h to obtain the adsorbent for high-temperature lithium extraction. The specific surface area of the prepared adsorbent for high-temperature lithium extraction is 356 m 2 / g.

[0035] Testing process: Prepare a 0.05 mo1 / L LiCl solution, adjust the pH to about 12 with LiOH solution. Take 100 mL of the above solution and pour it into a stoppered shaking flask. Add 0.1 g of the adsorbent for high-temperature lithium extraction at 80 °C, and perform Li + adsorption experiment on a shaker to measure the saturated adsorption capacity and saturated adsorption time of the adsorbent for high-temperature lithium extraction. At 25 °C, add 0.5 g of the adsorbent for high-temperature lithium extraction saturated with adsorption to 250 mL of 0.5 mol / L hydrochloric acid solution, and perform acid leaching for 2 h under stirring for regeneration. After regeneration, perform a cyclic adsorption experiment to test the cyclic adsorption performance of the adsorbent for high-temperature lithium extraction.

[0036] Figure 1XRD pattern of the adsorbent for high-temperature lithium extraction in Example 1. It can be seen from the figure that the adsorbent for high-temperature lithium extraction prepared by the present invention has a typical magnesium aluminate spinel structure and high crystallinity. The adsorbent prepared in this example, at 80 °C, Li + The saturated adsorption time is 12 h, the saturated adsorption capacity is 49 mg / g, and the saturated adsorption capacity is 38 mg / g after 30 cycles of use.

[0037] Example 2

[0038] At room temperature, 10 g of aluminum chloride, 7 g of magnesium chloride, 1 g of lithium hydroxide, 4 g of 2-methylimidazole, 1 g of hydrochloric acid, and 150 g of water were successively added to the reaction kettle. After stirring at 30 °C and 500 rpm for 1 h, a precursor solution was obtained;

[0039] At room temperature, polyethylene wax was prepared into a 0.1 mol / L N,N-dimethylformamide solution (pore-forming agent solution). 300 g of the pore-forming agent solution was gradually added dropwise to the precursor solution. After ultrasonic stirring at 1500 W and 60 °C for 1 h, ammonia water was added dropwise under ultrasonic stirring to adjust the pH of the solution to neutral. Then, it was stirred at 60 °C in a constant temperature water bath and 500 rpm for 3 h, crystallized at 220 °C for 3 h, filtered, washed with N,N-dimethylformamide solvent, dried at 150 °C for 12 h, and calcined at 1500 °C for 10 h to obtain spinel-type lithium magnesium aluminum oxide;

[0040] At room temperature, 10 g of spinel-type lithium magnesium aluminum oxide, 8000 g of 0.1 mol / L hydrochloric acid solution were added to the reaction kettle. After constant temperature oscillation at 50 °C for 2 h, it was filtered, washed, dried at 100 °C for 12 h, and calcined at 1500 °C for 10 h to obtain the adsorbent for high-temperature lithium extraction. The specific surface area of the prepared adsorbent for high-temperature lithium extraction is 338 m 2 / g.

[0041] The test process in Example 1 was adopted for testing.

[0042] The adsorbent prepared in this example, at 80 °C, Li + The saturated adsorption time is 15 h, the saturated adsorption capacity is 47 mg / g, and the saturated adsorption capacity is 39 mg / g after 30 cycles of use.

[0043] Example 3

[0044] At room temperature, 10 g of sodium hexafluoroaluminate, 8 g of magnesium fluoride, 3 g of lithium nitrate, 8 g of 2-methylimidazole, 3 g of nitric acid, and 180 g of water were successively added to the reaction kettle. After stirring at 50 °C and 100 rpm for 2 h, a precursor solution was obtained;

[0045] At room temperature, polyvinyl alcohol was prepared into a 0.1 mol / L N,N-dimethylformamide solution (pore-forming agent solution). 250 g of the pore-forming agent solution was added dropwise to the precursor solution. After ultrasonic stirring at 1000 W and 60 °C for 1 h, ammonia water was added dropwise under ultrasonic stirring to adjust the pH of the solution to neutral. Then, it was stirred at 90 °C in a constant temperature water bath at 100 rpm for 3 h, crystallized at 180 °C for 3 h, filtered, washed with N,N-dimethylformamide solvent, dried at 150 °C for 12 h, and calcined at 1200 °C for 16 h to obtain spinel-type lithium magnesium aluminum oxide;

[0046] At room temperature, 10 g of spinel-type lithium magnesium aluminum oxide, 7000 g of 0.1 mol / L nitric acid solution were added to the reaction kettle. After constant temperature oscillation at 30 °C for 5 h, it was filtered, washed, dried at 100 °C for 12 h, and then calcined at 1200 °C for 16 h to obtain the adsorbent for high-temperature lithium extraction. The specific surface area of the prepared adsorbent for high-temperature lithium extraction was 328 m 2 / g.

[0047] The test was carried out using the test process in Example 1.

[0048] For the adsorbent prepared in this example, at 80 °C, the + saturation adsorption time was 13 h, the saturation adsorption capacity was 46 mg / g, and the saturation adsorption capacity was 36 mg / g after 30 cycles of use.

[0049] Comparative Example 1 The addition of the pore-forming agent was omitted

[0050] At room temperature, 10 g of sodium hexafluoroaluminate, 7.5 g of magnesium fluoride, 2 g of lithium nitrate, 6 g of 2,2'-bipyridine, 2 g of nitric acid, and 200 g of water were successively added to the reaction kettle. After stirring at 40 °C and 300 rpm for 1 h, a precursor solution was obtained;

[0051] At room temperature, ammonia water was added dropwise to the precursor solution under ultrasonic stirring to adjust the pH of the solution to neutral. Then, it was stirred at 80 °C in a constant temperature water bath at 300 rpm for 3 h, crystallized at 200 °C for 5 h, filtered, washed with N,N-dimethylformamide solvent, dried at 150 °C for 12 h, and calcined at 1400 °C for 12 h to obtain spinel-type lithium magnesium aluminum oxide;

[0052] At room temperature, 10 g of spinel-type lithium magnesium aluminum oxide, 6000 g of 0.3 mol / L nitric acid solution were added to the reaction kettle. After constant temperature oscillation at 40 °C for 3 h, it was filtered, washed, dried at 100 °C for 12 h, and then calcined at 1400 °C for 12 h to obtain the adsorbent for high-temperature lithium extraction. The specific surface area of the prepared adsorbent for high-temperature lithium extraction was 197 m 2 / g.

[0053] The test was carried out using the test process in Example 1.

[0054] The adsorbent obtained in this comparative example, at 80 °C, Li + The saturated adsorption time is 18 h, the saturated adsorption capacity is 32 mg / g, and the saturated adsorption capacity is 20 mg / g after 30 cycles of use.

[0055] As can be seen from Comparative Example 1, compared with the examples, in the comparative example, since no pore-forming agent was added to the preparation system of the adsorbent for lithium extraction at high temperature, the specific surface area of the prepared adsorbent for lithium extraction at high temperature is small (<200 m 2 / g). Therefore, during the lithium extraction at high temperature, the adsorption amount of lithium is low.

[0056] Comparative Example 2 omits the introduction of fluorine / chlorine elements

[0057] At room temperature, 10 g of aluminum nitrate, 7.5 g of magnesium nitrate, 2 g of lithium nitrate, 6 g of 2,2'-bipyridine, 2 g of nitric acid, and 200 g of water were successively added to the reaction kettle. After stirring at 40 °C and 300 rpm for 1 h, a precursor solution was obtained;

[0058] At room temperature, polyvinyl alcohol was prepared into a 0.1 mol / L N,N-dimethylformamide solution (pore-forming agent solution). 600 g of the pore-forming agent solution was added dropwise to the precursor solution. After ultrasonic stirring at 1200 W and 50 °C for 1.5 h, ammonia water was added dropwise under ultrasonic stirring to adjust the pH of the solution to neutral. Then, it was stirred at 80 °C in a constant temperature water bath at 300 rpm for 3 h, crystallized at 200 °C for 5 h, filtered, washed with N,N-dimethylformamide solvent, dried at 150 °C for 12 h, and calcined at 1400 °C for 12 h to obtain spinel-type lithium magnesium aluminum oxide;

[0059] At room temperature, 10 g of spinel-type lithium magnesium aluminum oxide and 6000 g of 0.3 mol / L nitric acid solution were added to the reaction kettle. After constant temperature oscillation at 40 °C for 3 h, it was filtered, washed, dried at 100 °C for 12 h, and then calcined at 1400 °C for 12 h to obtain the adsorbent for lithium extraction at high temperature. The specific surface area of the prepared adsorbent for lithium extraction at high temperature is 296 m 2 / g.

[0060] The test process in Example 1 was used for testing.

[0061] The adsorbent obtained in this comparative example, at 80 °C, Li + The saturated adsorption time is 24 h, the saturated adsorption capacity is 26 mg / g, and the saturated adsorption capacity is 13 mg / g after 30 cycles of use.

[0062] As can be seen from Comparative Example 2, compared with the Examples, in the Comparative Example, since fluorine or chlorine elements were not introduced into the preparation system of the adsorbent for lithium extraction at high temperature, during the lithium extraction process at high temperature, it was difficult to achieve equilibrium between the adsorption and desorption of lithium ions on the adsorbent, resulting in an extended saturation adsorption time of lithium ions. Moreover, in a high-temperature environment, the adsorption binding force of lithium ions was limited only by the sieving and memory effects of lithium ion holes, and lithium ions were prone to desorb from the adsorbent, leading to a decrease in the adsorption amount of lithium ions during the lithium extraction process at high temperature.

[0063] Comparative Example 3 Replace the nitrogen-free organic ligand

[0064] At room temperature, 10 g of sodium hexafluoroaluminate, 7.5 g of magnesium fluoride, 2 g of lithium nitrate, 6 g of trimethylbenzene tricarboxylate methyl ester, 2 g of nitric acid, and 200 g of water were successively added to the reaction kettle. After stirring at 40 °C and 300 rpm for 1 h, a precursor solution was obtained;

[0065] At room temperature, polyvinyl alcohol was prepared into a 0.1 mol / L N,N-dimethylformamide solution (pore-forming agent solution). 600 g of the pore-forming agent solution was gradually added dropwise to the precursor solution. After ultrasonic stirring at 1200 W and 50 °C for 1.5 h, ammonia water was added dropwise under ultrasonic stirring to adjust the pH of the solution to neutral. Then, it was stirred at 80 °C in a constant temperature water bath at 300 rpm for 3 h, crystallized at 200 °C for 5 h, filtered, washed with N,N-dimethylformamide solvent, dried at 150 °C for 12 h, and calcined at 1400 °C for 12 h to obtain spinel-type lithium magnesium aluminum oxide;

[0066] At room temperature, 10 g of spinel-type lithium magnesium aluminum oxide and 6000 g of 0.3 mol / L nitric acid solution were added to the reaction kettle. After constant temperature oscillation at 40 °C for 3 h, it was filtered, washed, dried at 100 °C for 12 h, and then calcined at 1400 °C for 12 h to obtain the adsorbent for lithium extraction at high temperature. The specific surface area of the prepared adsorbent for lithium extraction at high temperature was 274 m 2 / g.

[0067] The test process in Example 1 was used for testing.

[0068] For the adsorbent prepared in this comparative example, at 80 °C, the Li + saturation adsorption time was 15 h, the saturation adsorption amount was 46 mg / g, and the saturation adsorption amount was 23 mg / g after 30 cycles of use.

[0069] As can be seen from Comparative Example 3, compared with the Examples, in the Comparative Example, since a nitrogen-free organic ligand was not used in the preparation system of the adsorbent for lithium extraction at high temperature, and trimethylbenzene tricarboxylate methyl ester was used as the organic ligand, although the adsorbent for lithium extraction at high temperature showed a relatively high saturation adsorption amount in the first adsorption, the saturation adsorption amount decreased rapidly after multiple cycles of use.

[0070] The above embodiments are only used to illustrate the technical solutions of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any form. Any technical solutions obtained by means of equivalent replacement or equivalent transformation fall within the protection scope of the present invention.

Claims

1. A preparation method of an adsorbent for extracting lithium at high temperature, characterized in that, It includes the following steps: Step 1: At room temperature, add an aluminum source, a magnesium source, a lithium source, an organic ligand, an acid source, and deionized water into a reaction kettle in sequence. After stirring at 30 - 50 °C for 0.5 - 2 h, a precursor solution is obtained. The aluminum source and the magnesium source are fluorine-containing salts or chlorine-containing salts. The aluminum source is sodium hexafluoroaluminate or aluminum chloride. The magnesium source is magnesium fluoride or magnesium chloride. The organic ligand is 2,2'-bipyridine or 2-methylimidazole. Step 2: At room temperature, prepare a 0.05 - 0.15 mol / L N,N-dimethylformamide solution of a pore-forming agent, and gradually add it dropwise to the precursor solution prepared in Step 1. After ultrasonic stirring for 1 - 2 h, a base solution is added dropwise under the state of ultrasonic stirring to adjust the pH of the solution to neutral. Then, stir in a constant temperature water bath at 60 - 90 °C for 2 - 5 h, carry out a crystallization reaction at 180 - 220 °C for 3 - 8 h, filter, wash with a solvent, dry at 140 - 160 °C for 10 - 24 h, and then calcine at 1200 - 1500 °C for 10 - 24 h to obtain a spinel-type lithium magnesium aluminum oxide. The mass ratio of the pore-forming agent solution to the precursor solution is (1 - 5):

1. Step 3: At room temperature, add the spinel-type lithium magnesium aluminum oxide prepared in Step 2 and an acidic solution into a reaction kettle. After constant temperature oscillation for 2 - 5 h, filter, wash, dry at 80 - 120 °C for 10 - 24 h, and then calcine at 1200 - 1500 °C for 10 - 24 h to obtain an adsorbent for high-temperature lithium extraction.

2. The preparation method according to claim 1, characterized in that: In Step 1, the lithium source is lithium hydroxide or lithium nitrate. The acid source is nitric acid or hydrochloric acid. The mass ratio of the aluminum source, the magnesium source, the lithium source, the organic ligand, the acid source, and deionized water is 1:(0.7 - 0.8):(0.1 - 0.3):(0.4 - 0.8):(0.1 - 0.3):(15 - 30).

3. The preparation method according to claim 1, characterized in that: In Step 2, the pore-forming agent is polyethylene wax or polyvinyl alcohol. The base solution is ammonia water or a 0.01 mol / L sodium carbonate solution.

4. The preparation method according to claim 1, wherein: In Step 3, the acidic solution is a 0.1 - 0.5 mol / L hydrochloric acid or nitric acid. The mass ratio of the acidic solution to the spinel-type lithium magnesium aluminum oxide is (600 - 800):

1.

5. The preparation method according to claim 1, characterized in that: In Steps 1 and 2, the stirring rate is 100 - 500 rpm. In Step 2, the ultrasonic stirring power is 1000 - 1500 W, and the temperature is 40 - 60 °C. In Step 3, the temperature of the constant temperature oscillation is 30 - 50 °C.

6. An adsorbent for high-temperature lithium extraction obtained by the preparation method according to any one of Claims 1 - 5.

7. An adsorbent for high-temperature lithium extraction according to claim 6, characterized in that: The Li of the adsorbent + has a saturated adsorption capacity greater than 40 mg / g and, after 30 cycles of use, has a saturated adsorption capacity greater than 35 mg / g.

8. Application of the adsorbent for high-temperature lithium extraction according to Claim 6 as an adsorbent for lithium extraction from geothermal fluid.

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