A resin for lithium extraction and its preparation method and application

Abstract

The present invention provides a lithium extraction resin, its preparation method, and application. The lithium extraction resin comprises an amino resin in which the amino functional group is replaced by at least one of the following groups (P): #imgabs0#(P), where #imgabs1# represents a chemical bond. The lithium extraction resin of the present invention significantly enhances its ability to adsorb lithium ions in alkaline environments and in the presence of high sodium ion concentrations. The resin, which is used to obtain a high lithium ion concentration in the solution obtained after desorption, is suitable for adsorbing lithium ions from aqueous solutions containing lithium ions, particularly lithium precipitation mother liquors and carbonate-type brines, and has high commercial application value. Furthermore, the preparation method of the lithium extraction resin of the present invention utilizes a one-pot process, resulting in high reaction efficiency, a stable synthesis process, and simple operation, making it suitable for large-scale industrial production.

Description

Technical Field

[0001] The invention belongs to the field of lithium adsorbents, and particularly relates to a resin for lithium extraction, a preparation method and an application thereof. Background Art

[0002] Lithium carbonate is a key raw material for lithium batteries, and demand is increasing with the development of new energy electric vehicles. Precipitation is the most widely used method for large-scale lithium carbonate production. Due to the low solubility of lithium carbonate, crude lithium carbonate can be obtained by adding sodium carbonate to a lithium-rich solution (typically composed primarily of lithium chloride and sodium chloride) for precipitation. However, due to the high salinity of this process, the precipitation yield is only around 80%, with approximately 20% of lithium remaining in the mother liquor, resulting in a large amount of lithium-precipitated mother liquor.

[0003] The lithium precipitation mother liquor is a multi-element water-salt system with complex components. + , Mg 2+ , B(III), SO4 2- etc. are at lower concentrations, among which Li + The concentration is relatively high (1.4~2.0 g / L), and it also contains a large amount of Na + (55~62 g / L), Cl - , CO3 2- Plasma, so the key to recovering lithium from lithium precipitation mother liquor lies in lithium-sodium separation. If the lithium precipitation mother liquor is directly discharged into the circulation system, it can only slightly increase the original halogen lithium content, resulting in insignificant economic benefits. Therefore, recovering lithium from the lithium precipitation mother liquor is extremely important. Lithium and sodium have similar properties, and high sodium-to-lithium ratios make lithium recovery more difficult. Therefore, how to economically and rationally utilize lithium precipitation mother liquor has always been a difficult problem.

[0004] At present, the processes for recovering lithium from lithium precipitation mother liquor mainly include membrane treatment, phosphoric acid precipitation, extraction, adsorption, etc. Among them, the membrane treatment method is difficult to apply industrially due to the short life of the membrane and high cost. The phosphoric acid precipitation method requires relatively precise control of pH. The added sodium phosphate leads to high cost, and the product lithium phosphate is cheaper than lithium carbonate, and the yield is low, so it does not have an economic advantage. In the extraction method, due to the different functional groups of the extractant, the extraction effect varies greatly, it is easy to emulsify, and procedures such as mixing, separation, and back extraction are required, and the process is relatively complicated. For example, the patent document with publication number CN116287777A proposes that phosphate ester can be used as a lithium extractant in the comprehensive utilization method of lithium precipitation mother liquor. The extractant belongs to a functionalized ionic liquid-based extraction system, in which the cation is a quaternary ammonium functionalized by a phosphate ion and the anion is selected from an alkyl phosphate. However, the ionic liquid is easily lost during the extraction process, and the equipment requirements are relatively high. In the adsorption method, the main types of adsorbents currently used in production include: inorganic adsorbents (such as aluminum-based adsorbents, manganese-based ion sieve adsorbents, titanium-based ion sieve adsorbents, natural mineral adsorbents, carbon material adsorbents, etc.); organic adsorbents (such as crown ether and calixarene adsorbents, ion-imprinted polymer adsorbents, layered metal acid salt adsorbents, porous foam adsorbents, selective ion channel adsorbents, etc.). In recent years, the development of resin adsorbents has attracted attention, but traditional organic ion exchange resins have low selectivity for lithium ions. Such adsorbents often struggle to improve their selectivity while also improving their adsorption capacity. Furthermore, raw material and process costs may still restrict industrial production. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a resin, preferably a resin for lithium extraction, which is an amino resin having an amino functional group substituted by at least one of the following groups (P):

[0006] (P)

[0007] in, Represents a chemical bond.

[0008] According to an embodiment of the present invention, the resin has a structure represented by the following formula (I):

[0009] (I)

[0010] in, Represents a group after one H on the amino group in the amino resin is replaced. Represents a chemical bond;

[0011] n represents an integer of 1 or greater.

[0012] According to an embodiment of the present invention, n≤the total number of amino functional groups possessed by the amino resin.

[0013] According to an embodiment of the present invention, the amino resin is an amino resin containing a primary amine functional group, which may also be referred to as a "primary amine resin." For example, the amino resin includes but is not limited to polystyrene primary amine resins, polyvinyl chloride primary amine resins, and acrylamide primary amine resins.

[0014] According to an embodiment of the present invention, the resin is a resin for lithium extraction.

[0015] The present invention also provides a method for preparing the above resin, wherein the preparation method comprises the following steps:

[0016] (1) The amino resin represented by formula (A) is reacted with a phosphate ester and an orthoformate to obtain a compound represented by formula (B):

[0017]

[0018] (2) Hydrolyzing the compound represented by formula (B) to obtain a polymer represented by formula (I):

[0019]

[0020] Where R is a straight or branched C 1-6 alkyl;

[0021] The amino resin and n have the definitions described above.

[0022] According to an embodiment of the present invention, the C 1-6 Alkyl is a straight or branched saturated hydrocarbon group having 1, 2, 3, 4, 5 or 6 carbon atoms. 1-6 The alkyl group may be straight chain or branched. 1-6 The alkyl group may be methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, or the like.

[0023] According to an embodiment of the present invention, the phosphate ester is selected from, but not limited to, diphosphite (C 1-6 alkyl) esters, tetra(C 1-6 One, two or more of the alkyl) methylene diphosphates.

[0024] According to an embodiment of the present invention, the diphosphite (C 1-6 The alkyl) ester can be selected from one, two or more of dimethyl phosphite, diethyl phosphite, triethyl phosphite and diisopropyl phosphite.

[0025] According to an embodiment of the present invention, the four (C 1-6 The alkyl) methylene diphosphate may be selected from one, two or more of tetramethyl methylene diphosphate, tetraethyl methylene diphosphate and tetraisopropyl methylene diphosphate.

[0026] According to an embodiment of the present invention, the orthoformate is selected from but not limited to tris(C 1-6 orthoformate, for example, one, two or more of triethyl orthoformate, trimethyl orthoformate and tributyl orthoformate.

[0027] According to an embodiment of the present invention, the reaction of step (1) is carried out by a one-pot process.

[0028] According to an embodiment of the present invention, in step (1), the molar ratio of the amino group in the amino resin to the phosphate ester is 1:(2-4), for example, 1:2, 1:2.5, 1:3, 1:3.5 or 1:4.

[0029] According to an embodiment of the present invention, in step (1), the molar ratio of the amino resin to the orthoformate is 1:(1-2), for example, 1:1, 1:1.5 or 1:2.

[0030] According to an embodiment of the present invention, step (1) can be performed under heating conditions. For example, the reaction temperature of step (1) is 125-135°C.

[0031] According to an embodiment of the present invention, in step (1), the reaction time can be 2 to 4 hours.

[0032] According to an embodiment of the present invention, in step (1), after the reaction is completed, the product is filtered, the solid product is washed, and the next step of the reaction is carried out. As an example, the washing process is to wash alternately with ethanol and water, for example, three times.

[0033] According to an embodiment of the present invention, in the step (2), the hydrolysis is carried out under acidic conditions.

[0034] According to an embodiment of the present invention, in the step (2), the hydrolysis is carried out in the presence of an acidic medium.

[0035] According to an embodiment of the present invention, in step (2), the hydrolysis is carried out in an aqueous acid solution. For example, the acid includes, but is not limited to, an inorganic acid, such as one, two, or more of hydrochloric acid, sulfuric acid, or hydrobromic acid. Preferably, the concentration of the hydrochloric acid or hydrobromic acid aqueous solution can be 4 to 8 mol / L; the concentration of the sulfuric acid aqueous solution can be 2 to 4 mol / L.

[0036] According to an embodiment of the present invention, step (2) can be performed under heating conditions. For example, the reaction temperature of step (2) is 80-85°C.

[0037] According to an embodiment of the present invention, in step (2), the reaction time can be 12 to 16 hours.

[0038] The present invention also provides a method for adsorbing lithium ions, comprising contacting the resin of the present invention with an aqueous solution containing lithium ions.

[0039] The present invention further provides the use of the resin according to the invention for adsorbing lithium ions, for example for adsorbing lithium ions from an aqueous solution containing lithium ions.

[0040] According to an embodiment of the present invention, the method for adsorbing lithium ions includes the following steps, or the resin includes the following steps when used to adsorb lithium ions:

[0041] Resin pretreatment: Take a chromatography column, load it with the resin of the present invention, and pass pure water-acidic solution-pure water-alkaline solution-pure water through the chromatography column in sequence;

[0042] Adsorption: An aqueous solution containing lithium ions is passed through a chromatography column;

[0043] Replacement: Rinse the adsorbed column with pure water;

[0044] Desorption: Pass an acidic solution through the column and retain the eluent.

[0045] Preferably, the method for adsorbing lithium ions comprises the following steps, or the resin, when used to adsorb lithium ions, comprises the following steps:

[0046] Chromatography column filling: The resin of the present invention is loaded into a chromatography column having a height-to-diameter ratio of 5 to 20;

[0047] According to an embodiment of the present invention, in the resin pretreatment step: a chromatography column is taken and the resin of the present invention is loaded; preferably, the resin is first rinsed with 2BV of pure water, then 2-4BV of an acidic solution (for example, a hydrogen ion concentration of 1-3 mol / L) is passed through the column at a flow rate of 0.5-2BV / h, and then rinsed with pure water until the pH of the eluate is 5-7; then 2-4BV of an alkaline aqueous solution (for example, a hydroxide ion concentration of 1-3 mol / L) is passed through the column at a flow rate of 0.5-2BV / h, and finally rinsed with pure water until the pH of the eluate is 7-10.

[0048] According to an embodiment of the present invention, the resin pretreatment step includes: first, washing the resin with 2BV of pure water, then passing the resin through the column with 3BV (1.5 mol / L) of hydrochloric acid at a flow rate of 2BV / h, and then rinsing with pure water until the pH of the eluate is 5-7; finally, passing the resin through the column with 4BV (1.5 mol / L) of sodium hydroxide aqueous solution at a flow rate of 2BV / h, and finally rinsing with pure water until the pH of the eluate is 7-10.

[0049] According to an embodiment of the present invention, in the adsorption step, depending on the lithium content in the brine, 0.5BV~200BV of an aqueous solution containing lithium ions can be passed through the chromatography column at a flow rate of 0.5~10BV / h. For example, when treating lithium precipitation mother liquor, 0.5~10BV of an aqueous solution containing lithium ions can be passed through the chromatography column at a flow rate of 0.5~2BV / h.

[0050] According to an embodiment of the present invention, the aqueous solution containing lithium ions (also referred to as "lithium-containing water sample") can be selected from, for example, natural salt lake brine containing lithium ions, concentrated natural salt lake brine, lithium precipitation mother liquor or other artificial water samples or natural water samples containing lithium ions.

[0051] According to an embodiment of the present invention, the lithium precipitation mother liquor may be the mother liquor obtained after precipitation of lithium salts during the lithium ore extraction process.

[0052] According to an embodiment of the present invention, the aqueous solution containing lithium ions may contain lithium ions and other metal cations. The other metal cations may be selected from at least one of sodium ions and potassium ions.

[0053] According to an embodiment of the present invention, the aqueous solution containing lithium ions may further contain anions, such as one or more of chloride ions, carbonate, bicarbonate, sulfate, borate, and the like.

[0054] As an example, the aqueous solution containing lithium ions may contain Li + 、Na + and 1, 2, 3, 4, 5 or 6 selected from the following: CO3 2- 、HCO3 - , K + 、Cl - 、B(III)、SO4 2- .

[0055] According to an embodiment of the present invention, the aqueous solution containing lithium ions further contains H + and OH - .

[0056] According to an embodiment of the present invention, there is no particular limitation on the pH value of the aqueous solution containing lithium ions, which may range from 1 to 14. Preferably, the aqueous solution containing lithium ions is nearly neutral or alkaline, and its pH value may range from 6 to 10.

[0057] According to an embodiment of the present invention, in the replacement step: the adsorbed chromatography column is flushed with pure water at a flow rate of 2 BV / h until the pH of the eluate is between 7 and 10;

[0058] According to an embodiment of the present invention, in the desorption step: an acidic solution (e.g., an acidic aqueous solution with a hydrogen ion concentration of 1.5 to 3 mol / L, such as hydrochloric acid with a hydrogen ion concentration of 1.5 to 3 mol / L) is passed through the column at a flow rate of 0.5 to 1 BV / h, and the desorption liquid is retained every 0.5 to 1 BV.

[0059] According to an embodiment of the present invention, the method for adsorbing lithium ions or the resin used for adsorbing lithium ions further comprises a resin regeneration step and a lithium recovery step.

[0060] According to an embodiment of the present invention, the resin regeneration step includes: flushing with pure water at a flow rate of 2BV / h until the pH of the eluate is 5-7; then passing 2-4BV of an alkaline aqueous solution (for example, a hydroxide ion concentration of 1.5-3 mol / L) through the column at a flow rate of 0.5-2BV / h, and then flushing with pure water until the pH of the eluate is 7-10.

[0061] According to an embodiment of the present invention, the lithium recovery step includes: before adsorbing the lithium in the lithium precipitation mother liquor, the column tail liquid adsorbed in the previous cycle is passed through the regenerated resin bed at a flow rate of 1~4BV / h to fully recover the lithium.

[0062] Beneficial effects

[0063] The present invention relates to a resin with excellent lithium ion selective adsorption properties. The resin of the present invention significantly improves its lithium ion adsorption capacity in an alkaline environment and in the presence of high sodium ion concentrations. Using this resin, the solution obtained after desorption has a high lithium ion concentration. The resin is suitable for adsorbing lithium ions from aqueous solutions containing lithium ions, particularly from lithium precipitation mother liquors and carbonate brines, and has high commercial application value. Furthermore, the preparation method of the resin of the present invention utilizes a one-pot process, resulting in high reaction efficiency, a stable synthesis process, and simple operation, making it suitable for large-scale industrial production. DETAILED DESCRIPTION

[0064] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention, rather than limit the scope of application of the present invention.In addition, should be understood that after reading the content narrated by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the application's appended claims.

[0065] Preparation Example 1: Synthesis of primary amine resin

[0066] Oil phase: 381 g styrene, 38 g 63% divinylbenzene, 210 g liquid wax, 4.3 g benzoyl peroxide, add the above materials to a 1 L beaker and mix well for use; aqueous phase: 2.5 L water is added to a 5 L three-necked reaction flask, 1.3 g carboxymethyl cellulose, 1.2 g gelatin, 2 mL 4% methylene blue solution are added, stirred and heated to 40 ° C for use; the above-prepared oil phase is poured into a 5 L three-necked flask, let it stand for 10 min, start stirring to evenly disperse the oil phase into spherical beads, heat to 70 ° C and keep warm for 2 h, then heat to 85 ° C for 2 h and keep warm for 3 h, heat to 90 ° C for 2 h and keep warm for 2 h, cool, separate the resin, wash with water, extract with methylal, wash with water, dry, and sieve to obtain polymer spheres of 0.3~1.5 mm.

[0067] 335 g of the polymer spheres obtained in the previous step were added to a dry 5 L reactor, and 1300 g of ethylene dichloride, 400 g of acetic anhydride, and 500 g of N-hydroxymethylphthalimide were added to the reactor. 500 g of concentrated sulfuric acid was added dropwise. Stirring was started and the temperature was raised to reflux for 10 h. The temperature was lowered, the beads were filtered out, washed with methylal, and then washed with water to obtain amide spheres.

[0068] The amide balls obtained in the previous step were added to a high-pressure reactor, and 1.5 times the mass of 30% sodium hydroxide solution was added. The temperature was raised to 170°C for reaction for 10 h, and the temperature was lowered. The mixture was filtered and washed with water to obtain a primary amine resin.

[0069] The resulting primary amine resin was sampled and its weak base exchange capacity was determined according to the national standard GB / T 5760-2000, "Determination of Exchange Capacity of Hydroxide-Form Anion Exchange Resins." The primary amine functional group content was 7.2 mmol / g dry resin (numerically equivalent to the weak base mass exchange capacity). The wet primary amine resin obtained by washing with water and 1.5 volumes of methanol were added to a three-necked flask and stirred for 1 hour. Stirring was then stopped and the methanol was filtered off. The resin was washed three times with methanol in this manner and then dried to obtain a dry primary amine resin for use in the following examples and comparative examples.

[0070] Example 1

[0071] 50 g of dry primary amine resin, 107 g of triethyl orthoformate, and 199 g of diethyl phosphite were added sequentially to a 1 L three-necked flask and stirred. The temperature was gradually raised to 135°C and the reaction was allowed to proceed for 2 hours. The reaction mixture was filtered out, and 300 mL of ethanol was added to the flask and stirred for half an hour. The stirring was then stopped, the ethanol was filtered out, and 300 mL of pure water was added and stirred for half an hour. The stirring was then stopped and the water was filtered out. The resin was washed three times in this manner to obtain the resin.

[0072] The resulting resin was hydrolyzed in 250 mL of 6 mol / L hydrochloric acid at 80°C for 14 h. After the reaction, the reaction solution was filtered and washed with water to obtain resin sample 1.

[0073] Example 2

[0074] Add 50 g of dry primary amine resin, 80 g of triethyl orthoformate, and 199 g of diethyl phosphite to a 1 L three-necked flask, stirring. Gradually raise the temperature to 130°C and allow the reaction to proceed for 3 hours. Filter the reaction mixture from the flask, add 300 mL of ethanol, and stir for half an hour. Stop stirring, filter out the ethanol, and add 300 mL of pure water, stirring for half an hour. Stop stirring and filter out the water. Repeat this process three times to obtain the resin.

[0075] The resulting resin was hydrolyzed in 250 mL of hydrobromic acid (5 mol / L) at 82°C for 12 h. After the reaction, the reaction solution was filtered and washed with water to obtain resin sample 2.

[0076] Example 3

[0077] Add 50 g of dry primary amine resin, 107 g of triethyl orthoformate, and 149 g of diethyl phosphite to a 1 L three-necked flask, stirring. Gradually raise the temperature to 135°C and allow the reaction to proceed for 4 hours. Filter the reaction mixture from the flask, add 300 mL of ethanol, and stir for half an hour. Stop stirring, filter out the ethanol, and add 300 mL of pure water, stirring for half an hour. Stop stirring and filter out the water. Repeat this process three times to obtain the resin.

[0078] The resulting resin was hydrolyzed in 250 mL of 4 mol / L hydrochloric acid at 85°C for 16 h. After the reaction, the reaction solution was filtered and washed with water to obtain resin sample 3.

[0079] Example 4

[0080] Add 50 g of dry primary amine resin, 80 g of triethyl orthoformate, and 149 g of diethyl phosphite to a 1 L three-necked flask, stirring. Gradually raise the temperature to 130°C and allow the reaction to proceed for 2 hours. Filter the reaction mixture from the flask, add 300 mL of ethanol, and stir for half an hour. Stop stirring, filter out the ethanol, and add 300 mL of pure water, stirring for half an hour. Stop stirring and filter out the water. Repeat this process three times to obtain the resin.

[0081] The resulting resin was hydrolyzed in 250 mL of 4 mol / L sulfuric acid at 80°C for 15 h. After the reaction, the reaction solution was filtered and washed with water to obtain resin sample 4.

[0082] Example 5

[0083] Add 50 g of dry primary amine resin, 53 g of trimethyl orthoformate, and 99 g of diethyl phosphite to a 1 L three-necked flask, stirring. Gradually raise the temperature to 125°C and allow the reaction to proceed for 4 hours. Filter the reaction mixture from the flask, add 300 mL of ethanol, and stir for half an hour. Stop stirring, filter out the ethanol, and add 300 mL of pure water, stirring for half an hour. Stop stirring and filter out the water. Repeat this process three times to obtain the resin.

[0084] The resulting resin was hydrolyzed in 250 mL of 2 mol / L sulfuric acid at 85°C for 13 h. After the reaction, the reaction solution was filtered and washed with water to obtain resin sample 5.

[0085] Comparative Example 1

[0086] 50 g of dry primary amine resin and 150 mL of methanol were added to a 1 L three-necked flask and stirred for 2 h. Stirring was stopped, the methanol was filtered off, and 150 mL of pure water was added. Stirring was continued for 1 h. Stirring was stopped, the liquid was filtered off, and the mixture was washed three times with water. To the filtered resin, 170 g of hydrochloric acid (36% wt) and 118 g of phosphorous acid were added. The mixture was stirred and gradually heated to 65°C. Then, 120 g of formaldehyde solution (37% wt) was added dropwise. After the additions were complete, the reaction mixture was gradually heated to 95°C and maintained at this temperature for 8 h. The reaction mixture was cooled to room temperature, filtered off, and 300 mL of pure water was added to the three-necked flask and stirred for half an hour. Stirring was stopped, and the water was filtered off. This process was repeated three times to obtain resin sample D1.

[0087] Comparative Example 2

[0088] 50 g of dry primary amine resin and 150 mL of methanol were added to a 1 L three-necked flask and stirred for 2 h. Stirring was stopped, the methanol was filtered off, and 150 mL of pure water was added. Stirring was continued for 1 h. Stirring was stopped, the liquid was filtered off, and the mixture was washed three times with water. 170 g of hydrochloric acid (36% wt) and 59 g of phosphorous acid were added to the filtered resin. The mixture was stirred and gradually heated to 65°C. Then, 60 g of formaldehyde solution (37% wt) was added dropwise. After the additions were complete, the temperature was gradually raised to 95°C and maintained for 8 h. The reaction was then terminated. The reaction mixture was cooled to room temperature, filtered off, and 300 mL of pure water was added to the three-necked flask and stirred for half an hour. Stirring was stopped, and the water was filtered off. This process was repeated three times to obtain resin sample D2.

[0089] The resin samples obtained in Examples 1-5 have the structure shown in the following formula (1), and the resin samples obtained in Comparative Examples 1-2 have the structure shown in the following formula (2):

[0090]

[0091] Application Examples

[0092] 1. Resin pretreatment

[0093] Take a glass chromatography column and load 60 mL (1 BV) of the resin sample prepared in the above Examples or Comparative Examples. First, rinse the resin with 2 BV of pure water. Next, pass 3 BV (1.5 mol / L) hydrochloric acid through the column at a flow rate of 2 BV / h. Then, rinse with pure water until the eluate has a pH of 5-7. Finally, pass 4 BV (1.5 mol / L) sodium hydroxide aqueous solution through the column at a flow rate of 2 BV / h. Finally, rinse with pure water until the eluate has a pH of 7-10.

[0094] 2. Resin adsorption and desorption

[0095] 1. Lithium extraction from resin

[0096] Adsorption: 10 BV of lithium precipitation mother liquor sample (composition see Table 1) was passed through the chromatography column at a flow rate of 2 BV / h, and a mixed sample of the column liquid was taken to determine the lithium content.

[0097] Replacement: flush with 4BV pure water at a flow rate of 2BV / h;

[0098] Desorption: Use 3BV (1.5 mol / L) hydrochloric acid to pass through the column at 1BV / h, take mixed samples every 0.5BV, and determine the lithium and sodium contents of the desorption solution.

[0099] 2. Resin regeneration

[0100] Rinse with 4BV of pure water at a flow rate of 2BV / h until the pH of the eluate is 5-7; then pass 4BV (1.5mol / L) sodium hydroxide aqueous solution through the column at a flow rate of 2BV / h, and rinse with pure water until the pH of the eluate is 7-10.

[0101] In actual application, before adsorbing lithium from lithium precipitation mother liquor, the tail liquid from the previous cycle of adsorption can be passed through the regenerated resin bed at a flow rate of 1~4BV / h to fully recover lithium.

[0102]

[0103] Table 1 Information of lithium precipitation mother liquor before column

[0104]

[0105] The resin samples obtained in the examples and comparative examples were used to separate lithium and sodium. The product performance and adsorption tail liquid data are shown in Table 2 below:

[0106] Table 2 Lithium content in tail liquid after resin adsorption and lithium adsorption capacity of resin

[0107]

[0108] The desorption test was carried out according to the desorption process, and the data are shown in Table 3 below:

[0109] Table 3 Resin desorption effect

[0110]

[0111] According to the data in Table 2 and Table 3 in the experiment, the resin samples of Examples 1-5 of the present invention have a more excellent lithium adsorption capacity than the resin samples of Comparative Examples 1-2, and the lithium adsorption capacity is increased to more than 1.8 times. Moreover, the mixed liquids after the column of 1.5~2.0BV and 2.0~2.5BV are combined as qualified product liquids. The sodium-lithium ratio of the qualified product liquid of the resin samples of Examples 1-5 is significantly reduced relative to the sodium-lithium ratio of the lithium mother liquor before the column, and is better than the sodium-lithium ratio of the qualified product liquid of the resin samples of Comparative Examples 1-2, and has a better sodium-lithium separation effect. Moreover, based on the better selectivity of the resin samples of Examples 1-5 for lithium, the lithium content of its qualified product liquid is also significantly better than that of the comparative example.

[0112] Moreover, the synthesis process of the lithium extraction resin of the present invention is more convenient, and a product with better performance can be obtained through a one-pot reaction, which has broad industrial application prospects.

[0113] The above is an exemplary description of the embodiments of the technical solution of the present invention. It should be understood that the scope of protection of the present invention is not limited to the above exemplary embodiments. Any modifications, equivalent substitutions, improvements, etc. made by those skilled in the art within the spirit and principles of the present invention shall be included in the scope of protection of the claims of this application.

Claims

1. A lithium extraction resin, wherein the lithium extraction resin has a structure represented by the following formula (I): （I） in, Represents a group after one H on the amino group in the amino resin is replaced. Represents a chemical bond; n represents an integer greater than or equal to 1, and n≤the total number of amino functional groups possessed by the amino resin; The amino resin is selected from polystyrene primary amine resin.

2. The lithium extraction resin according to claim 1, wherein the lithium extraction resin adsorbs lithium ions.

3. The method for preparing the lithium extraction resin according to claim 1 or 2, wherein the method comprises the following steps: (1) The amino resin represented by formula (A) is reacted with a phosphate ester and an orthoformate to obtain a compound represented by formula (B): The phosphate is selected from diphosphite (C 1-6 Alkyl) ester, the C 1-6 Alkyl is a straight or branched chain C 1-6 alkyl; (2) Hydrolyzing the compound represented by formula (B) to obtain a polymer represented by formula (I): in, R is a straight chain or branched C 1-6 alkyl; n has the definition as described in claim 1.

4. The method for preparing a lithium extraction resin according to claim 3, wherein the C 1-6 The alkyl group is selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, and hexyl.

5. The method for preparing a lithium extraction resin according to claim 3 or 4, wherein the reaction in step (1) is carried out by a one-pot process.

6. The method for preparing a lithium extraction resin according to claim 5, wherein: In step (1), the molar ratio of the amino group in the amino resin to the phosphate ester is 1:(2-4); or In step (1), the molar ratio of amino resin to orthoformate is 1:(1-2); or In step (2), the hydrolysis is carried out under acidic conditions.

7. A method for adsorbing lithium ions, the method comprising: Resin pretreatment: Take a chromatography column, load it with the lithium extraction resin according to claim 1 or 2, and pass pure water-acidic solution-pure water-alkaline solution-pure water through the chromatography column in sequence; The lithium extraction resin is contacted with an aqueous solution containing lithium ions.

8. The method of claim 7, wherein the method comprises the following steps: Resin pretreatment: Take a chromatography column, load the lithium extraction resin, and pass pure water-acidic solution-pure water-alkaline solution-pure water through the chromatography column in sequence; Adsorption: An aqueous solution containing lithium ions is passed through a chromatography column; Replacement: Rinse the adsorbed column with pure water; Desorption: Pass the column with acidic solution and retain the eluate; The method also includes a resin regeneration step and a lithium recovery step.

9. Use of the lithium extraction resin according to claim 1 or 2, wherein the lithium extraction resin is used to adsorb lithium ions.

10. The use according to claim 9, wherein the lithium extraction resin is used to adsorb lithium ions from an aqueous solution containing lithium ions.

11. The method according to claim 10, wherein the aqueous solution containing lithium ions is selected from natural salt lake brine containing lithium ions, concentrated natural salt lake brine or lithium precipitation mother liquor.

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