A lithium extraction resin, a preparation method and application thereof, and a lithium recovery method for a lithium-containing feed liquid

Abstract

This invention belongs to the field of chemical separation technology, specifically relating to a lithium extraction resin, its preparation method and application, and a method for recovering lithium from lithium-containing liquids. The lithium extraction resin provided by this invention comprises a resin and an ion exchanger distributed within the resin; the ion exchanger is an alkyl salicylate; the lithium extraction resin is porous spherical or near-spherical with a particle size of 100-200 mesh. The lithium extraction resin provided by this invention can be used as an extraction resin in the lithium recovery process, not only preventing the loss of the ion exchanger but also effectively overcoming the problem of difficult phase separation, improving the extraction rate, and reducing energy consumption. Furthermore, the resin can be recycled multiple times, significantly reducing operating costs. The recovery method provided by this invention has a simple process and is easy to operate, achieving both the high selectivity of solvent extraction and the advantages of simple equipment and high efficiency of ion exchange, thereby improving the recovery rate and reducing energy consumption.

Description

Technical Field

[0001] This invention belongs to the field of chemical separation technology, specifically relating to a lithium extraction resin, its preparation method and application, and a method for recovering lithium from lithium-containing liquid. Background Technology

[0002] Lithium is an important rare metal, widely used in batteries, metallurgy, aerospace, medicine, and military fields due to its excellent physicochemical properties such as low density and high electrochemical activity. Driven by the new energy technology revolution represented by high-energy lithium batteries and emerging technologies such as lithium-aluminum alloys and controlled thermonuclear fusion, global demand for lithium is rapidly increasing, and the global status of lithium resources is gradually rising.

[0003] Currently, Li₂CO₃ is mainly produced by reacting a concentrated lithium-rich solution with sodium carbonate to obtain lithium carbonate and lithium precipitation mother liquor. Due to the large solubility product of Li₂CO₃, the lithium precipitation rate in the system is generally only 70-80%. The traditional method for recovering lithium from the lithium precipitation mother liquor is to first neutralize the mother liquor with sulfuric acid to remove CO₃²⁻. 2- Then, the neutralized lithium precipitation mother liquor is evaporated, concentrated, and crystallized to separate anhydrous sodium sulfate, followed by a second lithium precipitation; however, due to the presence of impurity ions Na in the lithium precipitation mother liquor... + K + The high content of lithium carbonate limits its production to low-value industrial secondary lithium carbonate products, a long-standing and unresolved problem in the lithium industry. Therefore, improving and upgrading existing lithium carbonate production technologies is urgently needed.

[0004] To address the separation of lithium from other alkali metal ions in lithium precipitation mother liquor, patent documents CN115786735A and CN112342405A report methods for extracting lithium from alkaline solutions using a β-diketone-organophosphorus extraction system, and patent document CN115433830A reports a method for extracting lithium from alkaline lithium-containing solutions using a salicylic acid alkyl ester-organophosphorus extraction system. These methods have achieved good separation results. However, the above extraction systems are prone to phase separation difficulties when the metal ion loading is high, thus limiting the large-scale industrial application of the β-diketone / salicylic acid alkyl ester-organophosphorus extraction system. Summary of the Invention

[0005] The purpose of this invention is to provide a lithium extraction resin, its preparation method and application, and a method for recovering lithium from lithium-containing liquid. The lithium extraction resin provided by this invention can overcome the problem of difficult phase separation and has a good extraction effect.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a lithium extraction resin, comprising a resin and an ion exchanger distributed in the resin; the ion exchanger is an alkyl salicylate ester;

[0008] The lithium extraction resin is a porous spherical or near-spherical material with a particle size of 100-200 mesh.

[0009] Preferably, the resin is polystyrene resin;

[0010] The alkyl salicylate includes one or more of octyl salicylate, propyl salicylate, butyl salicylate, pentyl salicylate, and hexyl salicylate; the mass percentage of the ion exchanger in the lithium extraction resin is 10-60%.

[0011] Preferably, the lithium extraction resin has a pore volume of 2 mL / g or more and a specific surface area of ​​500 m². 2 / g or more, with an average pore size of 10nm or more.

[0012] The present invention also provides a method for preparing the lithium extraction resin described in the above technical solution, comprising the following steps:

[0013] The monomer, ion exchanger, crosslinking agent, initiator, and porogen are first mixed to obtain an organic phase; the ion exchanger is an alkyl salicylic acid ester.

[0014] The dispersant, surfactant, and water are mixed in a second phase to obtain an aqueous phase.

[0015] The organic phase and the aqueous phase are mixed for the third time to obtain a reaction solution;

[0016] The reaction solution is subjected to a polymerization reaction to obtain the lithium extraction resin.

[0017] Preferably, the monomer is styrene;

[0018] The crosslinking agent is divinylbenzene;

[0019] The initiator is benzoyl peroxide, azobisisobutyronitrile, cumene hydroperoxide, or lauroyl peroxide;

[0020] The pore-forming agent is sodium thiocyanate, sodium bicarbonate, sodium carbonate, n-butyl ether, or toluene;

[0021] The dispersant is gelatin or polyvinyl alcohol;

[0022] The surfactant is sodium dodecyl sulfonate or Triton.

[0023] Preferably, the volume ratio of the monomer to the crosslinking agent is 1:0.5 to 1.5;

[0024] The volume ratio of the monomer to the reaction solution is 1:10 to 20;

[0025] The ion exchanger in the organic phase has a mass percentage content of 10-60%.

[0026] The present invention also provides the application of the lithium extraction resin described in the above technical solution or the lithium extraction resin obtained by the preparation method described in the above technical solution in lithium recovery.

[0027] The present invention also provides a method for recovering lithium from lithium-containing liquid, comprising the following steps:

[0028] The lithium-containing liquid is passed through a lithium extraction resin for adsorption, resulting in an adsorption tail liquid and a lithium-rich resin; the lithium extraction resin is the lithium extraction resin described in the above technical solution or the lithium extraction resin obtained by the preparation method described in the above technical solution.

[0029] The acid solution is passed into the lithium-rich resin to desorb the lithium and obtain a lithium desorption solution.

[0030] Preferably, the lithium concentration in the lithium-containing solution is 0.05–10 g / L; the flow rate of the lithium-containing solution is 2–5 BV / h.

[0031] The ratio of lithium concentration in the adsorption tail liquid to lithium concentration in the lithium-containing feed liquid is 1:10 to 100; adsorption stops when the lithium concentration in the adsorption tail liquid reaches 0.005 to 1 g / L.

[0032] Preferably, the acid solution includes one or more of hydrochloric acid solution, nitric acid solution, and sulfuric acid solution; the hydrogen ion concentration of the acid solution is 0.05–6 mol / L.

[0033] The flow rate of the acid solution is 0.5–2 BV / h.

[0034] This invention provides a lithium extraction resin, comprising a resin and an ion exchanger distributed within the resin; the ion exchanger is an alkyl salicylate ester; the lithium extraction resin is porous spherical or near-spherical with a particle size of 100-200 mesh. The lithium extraction resin provided by this invention can be used as an extraction resin in the lithium recovery process, not only preventing the loss of the ion exchanger but also effectively overcoming the problem of difficult phase separation in liquid extraction systems, improving the extraction rate, and reducing energy consumption. Furthermore, this resin can be recycled multiple times, significantly reducing operating costs.

[0035] The recovery method provided by this invention has a simple process and is easy to operate. It achieves the high selectivity of solvent extraction and the advantages of simple equipment and high efficiency of ion exchange. It can improve the recovery rate and reduce energy consumption. Moreover, the process does not require the use of co-extractants and diluents, thus avoiding the environmental problems caused by the volatilization of organic solvents. Detailed Implementation

[0036] This invention provides a lithium extraction resin, comprising a resin and an ion exchanger distributed in the resin; the ion exchanger is an alkyl salicylate ester;

[0037] The lithium extraction resin is a porous spherical or near-spherical material with a particle size of 100-200 mesh.

[0038] In this invention, unless otherwise specified, all raw material components are commercially available products well known to those skilled in the art.

[0039] In this invention, the resin is preferably polystyrene resin.

[0040] In this invention, the alkyl chain in the alkyl salicylate is preferably C3 to C8; the alkyl salicylate preferably includes one or more of octyl salicylate, propyl salicylate, butyl salicylate, pentyl salicylate, and hexyl salicylate, more preferably one or more of octyl salicylate, butyl salicylate, and pentyl salicylate; the octyl salicylate preferably includes isooctyl salicylate and / or n-octyl salicylate; the butyl salicylate is preferably n-butyl salicylate; the pentyl salicylate is preferably isoamyl salicylate; when the alkyl salicylate is two or more of the above types, the present invention does not impose any special limitation on the proportion of the alkyl salicylate; the alkyl salicylate is soluble in a styrene-divinylbenzene system; the mass percentage of the ion exchanger in the lithium extraction resin is preferably 10-60%, more preferably 15-50%.

[0041] In this invention, the lithium extraction resin is preferably opaque white; the particle size is 100-200 mesh, preferably 100-200 mesh; the pore volume of the lithium extraction resin is preferably 2 mL / g or more, more preferably 3-5 mL / g; and the specific surface area is preferably 500 m². 2 / g or more, more preferably 600-800m 2 / g; the average pore size is preferably 10 nm or more, more preferably 10 to 12 nm.

[0042] The present invention also provides a method for preparing the lithium extraction resin described in the above technical solution, comprising the following steps:

[0043] The monomer, ion exchanger, crosslinking agent, initiator, and porogen are first mixed to obtain an organic phase; the ion exchanger is an alkyl salicylic acid ester.

[0044] The dispersant, surfactant, and water are mixed in a second phase to obtain an aqueous phase.

[0045] The organic phase and the aqueous phase are mixed for the third time to obtain a reaction solution;

[0046] The reaction solution is subjected to a polymerization reaction to obtain the lithium extraction resin.

[0047] In this invention, monomers, ion exchangers, crosslinking agents, initiators, and porogens are first mixed to obtain an organic phase.

[0048] In this invention, the monomer is preferably styrene; the advantage of using styrene as a monomer is that it has excellent alkali resistance and is suitable for the extraction of lithium-containing solutions.

[0049] In this invention, the alkyl chain in the alkyl salicylate is preferably C3 to C8; the alkyl salicylate preferably includes one or more of octyl salicylate, propyl salicylate, butyl salicylate, pentyl salicylate, and hexyl salicylate, more preferably one or more of octyl salicylate, butyl salicylate, and pentyl salicylate; the octyl salicylate preferably includes isooctyl salicylate and / or n-octyl salicylate; the butyl salicylate is preferably n-butyl salicylate; the pentyl salicylate is preferably isoamyl salicylate; when the alkyl salicylate is two or more of the above types, this invention does not impose any special limitation on the proportion of the alkyl salicylate; the alkyl salicylate is soluble in a styrene-divinylbenzene system.

[0050] In this invention, the crosslinking agent is preferably divinylbenzene; the volume ratio of the monomer to the crosslinking agent is preferably 1:0.5 to 1.5, more preferably 1:1 to 1.5.

[0051] In this invention, the initiator is preferably benzoyl peroxide, azobisisobutyronitrile, cumene hydroperoxide or lauroyl peroxide, more preferably benzoyl peroxide, azobisisobutyronitrile or cumene hydroperoxide;

[0052] The volume ratio of the monomer to the mass ratio of the initiator is preferably 25 mL: 0.25–1 g, more preferably 25 mL: 0.4–0.8 g.

[0053] In this invention, the porogen is preferably sodium thiocyanate, sodium bicarbonate, sodium carbonate, n-butyl ether, or toluene, more preferably sodium thiocyanate, sodium bicarbonate, or sodium carbonate; the volume ratio of the monomer to the mass ratio of the porogen is preferably 25 mL: 0.1–0.5 g, more preferably 25 mL: 0.2–0.4 g.

[0054] In this invention, the mass percentage of the ion exchanger in the organic phase is preferably 10-60%, more preferably 15-50%.

[0055] In this invention, the first mixing process is preferably as follows: first, the ion exchanger is added to the monomer, then mixed with the crosslinking agent and the initiator for a first stirring, and finally mixed with the porogen for a second stirring; this invention does not impose any special limitations on the first stirring process, and the initiator can be completely dissolved using a method known to those skilled in the art; this invention does not impose any special limitations on the second stirring process, and the organic phase can be made uniform and stable using a method known to those skilled in the art.

[0056] The present invention involves mixing a dispersant, a surfactant, and water to obtain an aqueous phase.

[0057] In this invention, the dispersant is preferably gelatin or polyvinyl alcohol; the mass ratio of the dispersant to water is preferably 0.5 to 1:300, more preferably 0.5 to 1:300.

[0058] In this invention, the surfactant is preferably sodium dodecyl sulfonate or Triton; the Triton is preferably TX-100; the mass ratio of the surfactant to water is preferably 0.1-0.25:300, more preferably 0.15-0.2:300.

[0059] The present invention does not impose any special limitations on the second mixing process, and any method known to those skilled in the art can be used.

[0060] After obtaining the organic phase and the aqueous phase, the present invention mixes the organic phase and the aqueous phase in a third step to obtain a reaction solution.

[0061] The present invention does not impose any special limitations on the third mixing process, and any method known to those skilled in the art can be used.

[0062] In this invention, the volume ratio of the monomer to the reaction solution is preferably 1:10 to 20, and more preferably 1:12 to 18.

[0063] After obtaining the reaction solution, the present invention performs a polymerization reaction on the reaction solution to obtain the lithium extraction resin.

[0064] In this invention, the polymerization reaction is preferably suspension polymerization; the polymerization reaction preferably includes a first stage and a second stage carried out sequentially; the temperature of the first stage is preferably 80-85°C, and the time is preferably 0.25-1h, more preferably 0.5h; the temperature of the second stage is preferably 90-95°C, more preferably 90°C, and the time is preferably 2-4h; the function of the second stage is to ensure that the residual initiator and monomer react completely; the polymerization reaction is carried out under stirring conditions; this invention does not impose any special limitations on the stirring process, and any method known to those skilled in the art can be used.

[0065] In this invention, the polymerization reaction is preferably followed by sequential cooling, washing, filtration, and drying. The cooling process is not particularly limited in this invention; cooling to below 50°C can be performed using methods well known to those skilled in the art. The washing process is not particularly limited in this invention; washing until the washing liquid is clear can be performed using methods well known to those skilled in the art. The filtration and drying processes are not particularly limited in this invention; methods well known to those skilled in the art can be used.

[0066] The lithium extraction resin provided by this invention can be used as an extraction resin in the lithium recovery process. It not only prevents the loss of ion exchangers but also effectively overcomes the problem of difficult phase separation, improves the extraction rate, and reduces energy consumption. Furthermore, the resin can be recycled multiple times, significantly reducing operating costs.

[0067] The present invention also provides the application of the lithium extraction resin described in the above technical solution or the lithium extraction resin obtained by the preparation method described in the above technical solution in lithium recovery.

[0068] The present invention also provides a method for recovering lithium from lithium-containing liquid, comprising the following steps:

[0069] The lithium-containing liquid is passed through a lithium extraction resin for adsorption, resulting in an adsorption tail liquid and a lithium-rich resin; the lithium extraction resin is the lithium extraction resin described in the above technical solution or the lithium extraction resin obtained by the preparation method described in the above technical solution.

[0070] The acid solution is passed into the lithium-rich resin to desorb the lithium and obtain a lithium desorption solution.

[0071] This invention involves passing a lithium-containing liquid into a lithium extraction resin for adsorption, resulting in an adsorption tail liquid and a lithium-rich resin.

[0072] In this invention, the adsorption process preferably includes washing; the washing includes acid washing and alkali washing; this invention does not impose any special limitations on the acid washing and alkali washing process, and any method known to those skilled in the art can be used; the purpose of acid washing and alkali washing is to wash away residual pore-forming agents, surfactants and residual ion exchangers in the resin, so that the resin has a stable macroporous structure.

[0073] In this invention, the adsorption process preferably includes filling an ion exchange column with lithium extraction resin; the ion exchange column has a size of Φ35mm×400mm; the filling amount is preferably 100-150g, more preferably 100-120g; the column diameter ratio is preferably 5-10, more preferably 6-9.

[0074] In this invention, the lithium concentration in the lithium-containing solution is preferably 0.05–10 g / L, more preferably 0.1–5 g / L; the hydroxide ion concentration is preferably 0.01–6 mol / L, more preferably 0.1–5 g / L; the lithium-containing solution is preferably a lithium precipitation mother liquor; and the flow rate of the lithium-containing solution is preferably 2–5 BV / h, more preferably 3–4 BV / h.

[0075] In this invention, the ratio of lithium concentration in the adsorption tail liquid to lithium concentration in the lithium-containing feed liquid is preferably 1:10 to 100, more preferably 1:20 to 80; the adsorption is preferably stopped when the lithium concentration in the adsorption tail liquid reaches 0.005 to 1 g / L, more preferably 0.005 to 0.05 g / L.

[0076] After obtaining the lithium-rich resin, the present invention introduces acid into the lithium-rich resin to desorb the lithium and obtain a lithium desorption solution.

[0077] In this invention, the process before desorption also includes washing; the washing reagent is preferably water; the washing flow rate is preferably 0.5-5 BV / h, more preferably 1-4 BV / h; the washing time is preferably 10-60 min, more preferably 30-60 min; the reason for washing is that after the adsorption mother liquor flows through the resin column for adsorption, there is residual mother liquor in the resin column. The mother liquor contains impurities such as sodium and potassium. If water is not used for washing, sodium and potassium will enter the desorption liquid during the desorption stage, and the sodium and potassium content in the desorption liquid is likely to exceed the standard, which will result in the failure to achieve the purpose of preparing a relatively pure lithium solution.

[0078] In this invention, the acid solution preferably includes one or more of hydrochloric acid solution, nitric acid solution and sulfuric acid solution, more preferably hydrochloric acid solution and / or sulfuric acid solution; the hydrogen ion concentration of the acid solution is preferably 0.05-6 mol / L, more preferably 0.1-5 mol / L; the flow rate of the acid solution is preferably 0.5-2 BV / h, more preferably 1-2 BV / h.

[0079] In this invention, the lithium concentration in the lithium desorption solution is preferably reduced to 0.01-1 g / L and desorption is stopped, more preferably to 0.05-0.5 g / L.

[0080] In this invention, the desorption process preferably includes washing; the washing reagent is preferably water; the washing flow rate is preferably 0.5–5 BV / h, more preferably 1–4 BV / h; the washing time is preferably 10–60 min, more preferably 30–60 min; the purpose of washing is to achieve the regeneration and reuse of the lithium extraction resin.

[0081] The recovery method provided by this invention has a simple process and is easy to operate. It achieves the high selectivity of solvent extraction and the advantages of simple equipment and high efficiency of ion exchange. It can improve the recovery rate and reduce energy consumption. Moreover, the process does not require the use of co-extractants and diluents, thus avoiding the environmental problems caused by the volatilization of organic solvents.

[0082] To further illustrate the present invention, the following detailed descriptions, in conjunction with embodiments, illustrate the lithium extraction resin, its preparation method, its application, and the method for recovering lithium from lithium-containing liquids provided by the present invention. However, these descriptions should not be construed as limiting the scope of protection of the present invention.

[0083] Example 1

[0084] Resin preparation: In a dry beaker, add 50 mL of isooctyl salicylate, 25 mL of styrene, 25 mL of divinylbenzene, and 0.25 g of benzoyl peroxide initiator, and stir until the initiator is completely dissolved. Add 0.5 g of sodium thiocyanate as a porogen, stir the above oil phase evenly, and then add it to a 500 mL three-necked flask containing 300 mL of deionized water, 0.5 g of gelatin, and 0.25 g of sodium dodecyl sulfonate. Attach a thermometer, condenser, and electric stirrer, and react at 80 °C for 0.5 h. Then raise the temperature to 90 °C and react for 3 h to ensure the remaining initiator and monomers react completely. Cool to about 50 °C, wash with deionized water until the aqueous phase is clear, filter, and dry for later use. The obtained resin is opaque white in color, contains 48.9% isooctyl salicylate, has a particle size of 100-200 mesh, a pore volume of 4.25 mL / g, and an optimal specific surface area of ​​824.3 m². 2 / g, with an average pore size of 12.6nm.

[0085] Adsorption: Weigh 100g of extraction resin, wash it several times with dilute acid and dilute alkali, and then pack it into an ion exchange column with a column diameter ratio of 7. Pass the lithium precipitation mother liquor into the ion exchange column at a flow rate of 5 BV / h for adsorption. The lithium concentration in the lithium-containing solution is 2 g / L, the sodium concentration is 50 g / L, and the hydroxide concentration is 0.1 mol / L. Stop adsorption when the lithium concentration in the effluent reaches 0.05 g / L. Wash the resin with water at a flow rate of 2 BV / h for 30 min. After washing, proceed to the next step.

[0086] Desorption: The adsorbed resin was desorbed using sulfuric acid with a hydrogen ion concentration of 3 mol / L. The desorbent was passed through the resin after lithium adsorption at a flow rate of 0.5 BV / h. Desorption was stopped when the lithium concentration in the outlet desorbent was less than 0.1 g / L.

[0087] Regeneration: After the adsorption and desorption processes are completed, the resin is washed with water at a flow rate of 1.5 BV / h for 30 minutes. The regenerated resin after washing can enter the next adsorption cycle.

[0088] In this embodiment, the TOC value in the adsorption tail liquid is 12.0 mg / L, and the TOC value in the desorption liquid is 19.5 mg / L; the lithium desorption rate in the desorption step is 99%, and the lithium concentration in the desorption liquid is 13 g / L.

[0089] Example 2

[0090] Resin preparation: In a dry beaker, add 20 mL of isoamyl salicylate, 25 mL of styrene, 25 mL of divinylbenzene, and 0.25 g of initiator azobisisobutyronitrile (AIBN). Stir until the initiator is completely dissolved. Add 0.5 g of porogen sodium thiocyanate. After stirring the above oil phase evenly, add it to a 500 mL three-necked flask containing 300 mL of deionized water, 0.5 g of gelatin, and 0.5 g of sodium dodecyl sulfonate. Attach a thermometer, condenser, and electric stirrer. React at 80 °C for 0.5 h, then raise the temperature to 90 °C and react for 2 h to ensure complete reaction of the remaining initiator and monomers. Cool to approximately 50 °C, wash with deionized water until the aqueous phase is clear, filter, and dry for later use. The obtained resin is opaque white in color, contains 25.7% isoamyl salicylate, has a sieve particle size of 100-200 mesh, a pore volume of 3.78 mL / g, and an optimal specific surface area of ​​810.4 m². 2 / g, with an average pore size of 10.1nm.

[0091] Adsorption: Weigh 100g of extraction resin, wash it several times with dilute acid and dilute alkali, and then pack it into an ion exchange column with a column diameter ratio of 7. Pass the lithium precipitation mother liquor into the ion exchange column at a flow rate of 2 BV / h for adsorption. The lithium concentration in the lithium-containing solution is 0.1 g / L, the sodium concentration is 10 g / L, and the hydroxide concentration is 0.5 mol / L. Stop adsorption when the lithium concentration in the effluent reaches 0.01 g / L. Wash the resin with water at a flow rate of 2 BV / h for 30 min. After washing, proceed to the next step.

[0092] Desorption: The adsorbed resin was desorbed using sulfuric acid with a hydrogen ion concentration of 3 mol / L. The desorbent was passed through the resin after lithium adsorption at a flow rate of 0.5 BV / h. Desorption was stopped when the lithium concentration in the outlet desorbent was less than 0.1 g / L.

[0093] Regeneration: After the adsorption and desorption processes are completed, the resin is washed with water at a flow rate of 1.0 BV / h for 30 minutes. The regenerated resin after washing can enter the next adsorption cycle.

[0094] In this embodiment, the TOC value in the adsorption tail liquid is 15.5 mg / L, and the TOC value in the desorption liquid is 23.0 mg / L; the lithium desorption rate in the desorption step is 99.3%, and the lithium concentration in the desorption liquid is 1.5 g / L.

[0095] Example 3

[0096] Resin Preparation: In a dry beaker, add 15 mL of n-butyl salicylate, 25 mL of styrene, 25 mL of divinylbenzene, and 0.5 g of lauroyl peroxide initiator, and stir until the initiator is completely dissolved. Add 0.5 g of sodium thiocyanate as a pore-forming agent. After stirring the above oil phase evenly, add it to a 500 mL three-necked flask containing 300 mL of deionized water, 0.5 g of gelatin, and 0.5 g of sodium dodecyl sulfonate. Attach a thermometer, condenser, and electric stirrer, and react at 85 °C for 1 h. Then raise the temperature to 90 °C and react for 2 h to ensure complete reaction of residual initiator and monomers. Cool to about 50 °C, wash with deionized water until the aqueous phase is clear, filter, and dry for later use. The obtained resin is opaque white in color, with an isooctyl salicylate content of 20.1%, a sieve particle size of 100–200 mesh, a pore volume of 5.10 mL / g, and a preferred specific surface area of ​​794.3 m². 2 / g, with an average pore size of 10.9nm.

[0097] Adsorption: Weigh 100g of extraction resin, wash it several times with dilute acid and dilute alkali, and then pack it into an ion exchange column with a column diameter ratio of 7. Pass the lithium precipitation mother liquor into the ion exchange column at a flow rate of 2 BV / h for adsorption. The lithium concentration in the lithium-containing solution is 5 g / L, the sodium concentration is 70 g / L, and the hydroxide concentration is 0.1 mol / L. Stop adsorption when the lithium concentration in the effluent reaches 0.1 g / L. Wash the resin with water at a flow rate of 0.5 BV / h for 30 min. After washing, proceed to the next step.

[0098] Desorption: The adsorbed resin was desorbed using sulfuric acid with a hydrogen ion concentration of 6 mol / L. The desorbent was passed through the resin after lithium adsorption at a flow rate of 0.5 BV / h. Desorption was stopped when the lithium concentration in the outlet desorbent was less than 0.1 g / L.

[0099] Regeneration: After the adsorption and desorption processes are completed, the resin is washed with water at a flow rate of 0.5 BV / h for 60 minutes. The regenerated resin after washing can enter the next adsorption cycle.

[0100] In this embodiment, the TOC value in the adsorption tail liquid is 21.0 mg / L, and the TOC value in the desorption liquid is 30.5 mg / L; the lithium desorption rate in the desorption step is 98.7%, and the lithium concentration in the desorption liquid is 10 g / L.

[0101] Example 4

[0102] Resin preparation: In a dry beaker, add 15 mL of isooctyl salicylate, 15 mL of isoamyl salicylate, 25 mL of styrene, 25 mL of divinylbenzene, and 0.5 g of benzoyl peroxide initiator. Stir until the initiator is completely dissolved. Add 0.5 g of sodium thiocyanate as a porogen. After stirring the above oil phase evenly, add it to a 500 mL three-necked flask containing 300 mL of deionized water, 1.0 g of gelatin, and 0.5 g of sodium dodecyl sulfonate. Attach a thermometer, condenser, and electric stirrer. React at a constant temperature of 85 °C for 1 h, then raise the temperature to 95 °C and react for 2 h to ensure complete reaction of the remaining initiator and monomers. Cool to about 50 °C, wash with deionized water until the aqueous phase is clear, filter, and dry for later use. The obtained resin is opaque white in color, contains 37.5% isooctyl salicylate, has a particle size of 100-200 mesh, a pore volume of 5.60 mL / g, and an optimal specific surface area of ​​763.2 m². 2 / g, with an average pore size of 11.1nm.

[0103] Adsorption: Weigh 100g of extraction resin, wash it several times with dilute acid and dilute alkali, and then pack it into an ion exchange column with a column diameter ratio of 7. Pass the lithium precipitation mother liquor into the ion exchange column at a flow rate of 5 BV / h for adsorption. The lithium concentration in the lithium-containing solution is 2.5 g / L, the sodium concentration is 50 g / L, and the hydroxide concentration is 0.8 mol / L. Stop adsorption when the lithium concentration in the effluent reaches 0.5 g / L. Wash the resin with water at a flow rate of 2 BV / h for 30 min. After washing, proceed to the next step.

[0104] Desorption: The adsorbed resin was desorbed using sulfuric acid with a hydrogen ion concentration of 3 mol / L. The desorbent was passed through the lithium-adsorbed resin at a flow rate of 2 BV / h. Desorption was stopped when the lithium concentration in the outlet desorbent was less than 1 g / L.

[0105] Regeneration: After the adsorption and desorption processes are completed, the resin is washed with water at a flow rate of 5 BV / h for 10 minutes. The regenerated resin after washing can enter the next cycle of adsorption process.

[0106] In this embodiment, the TOC value in the adsorption tail liquid is 11.5 mg / L, and the TOC value in the desorption liquid is 31.7 mg / L; the lithium desorption rate in the desorption step is 95.5%, and the lithium concentration in the desorption liquid is 25 g / L.

[0107] Example 5

[0108] Resin preparation: In a dry beaker, add 15 mL of isoamyl salicylate, 25 mL of styrene, 25 mL of divinylbenzene, and 0.25 g of benzoyl peroxide initiator, and stir until the initiator is completely dissolved. Add 0.5 g of sodium bicarbonate porogen, stir the above oil phase evenly, and then add it to a 500 mL three-necked flask containing 300 mL of deionized water, 0.5 g of gelatin, and 0.25 g of sodium dodecyl sulfonate. Attach a thermometer, condenser, and electric stirrer, and react at 80 °C for 0.5 h. Then raise the temperature to 95 °C and react for 2 h to ensure the remaining initiator and monomers react completely. Cool to about 50 °C, wash with deionized water until the aqueous phase is clear, filter, and dry for later use. The obtained resin is opaque white in color, contains 23.0% isooctyl salicylate, has a sieve particle size of 100-200 mesh, a pore volume of 3.25 mL / g, and an optimal specific surface area of ​​768.0 m². 2 / g, with an average pore size of 12.0nm.

[0109] Adsorption: Weigh 100g of extraction resin, wash it several times with dilute acid and dilute alkali, and then pack it into an ion exchange column with a column diameter ratio of 7. Pass the lithium precipitation mother liquor into the ion exchange column at a flow rate of 2 BV / h for adsorption. The lithium concentration in the lithium-containing solution is 0.05 g / L, the sodium concentration is 10 g / L, and the hydroxide concentration is 0.03 mol / L. Stop adsorption when the lithium concentration in the effluent reaches 0.005 g / L. Wash the resin with water at a flow rate of 1 BV / h for 30 min. After washing, proceed to the next step.

[0110] Desorption: The adsorbed resin was desorbed using sulfuric acid with a hydrogen ion concentration of 0.05 mol / L. The desorbent was passed through the resin after lithium adsorption at a flow rate of 0.5 BV / h. Desorption was stopped when the lithium concentration in the outlet desorbent was less than 0.01 g / L.

[0111] Regeneration: After the adsorption and desorption processes are completed, the resin is washed with water at a flow rate of 0.5 BV / h for 60 minutes. The regenerated resin after washing can enter the next adsorption cycle.

[0112] In this embodiment, the TOC value in the adsorption tail liquid was 20.1 mg / L, and the TOC value in the desorption liquid was 33.9 mg / L; the lithium desorption rate in the desorption step was 99.4%, and the lithium concentration in the desorption liquid was 0.8 g / L.

[0113] Comparative Example

[0114] Using isooctyl salicylate as the extractant, trialkylphosphine oxide as the co-extractant, and sulfonated kerosene as the diluent, an organic phase #1 for extraction was obtained. The concentrations of isooctyl salicylate and trialkylphosphine oxide in this organic phase were 1.0 mol / L, with the remainder being sulfonated kerosene. Using benzoyltrifluoroacetone as the extractant, trialkylphosphine oxide as the co-extractant, and sulfonated kerosene as the diluent, an organic phase #2 for extraction was obtained. The concentrations of benzoyltrifluoroacetone and trialkylphosphine oxide in this organic phase were 1.0 mol / L, with the remainder being sulfonated kerosene.

[0115] A lithium-containing solution with a lithium concentration of 0.05 g / L, a sodium concentration of 10 g / L, and a hydroxide concentration of 0.03 mol / L was used as the extraction aqueous phase.

[0116] The above-mentioned #1 and #2 organic phases were subjected to single-stage extraction with the extraction aqueous phase at an extraction ratio (O / A) of 1:1 for 15 min. After the extraction reached equilibrium, the phases were allowed to separate, yielding #1 raffinate and #2 raffinate. The loaded organic phase was then back-extracted with 3 mol / L hydrochloric acid solution at an O / A ratio of 10:1 to obtain #1 back-extract and #2 back-extract.

[0117] The TOC values ​​in the raffinate and back-extraction solution were measured. The TOC value in raffinate #1 was 351.2 mg / L, and the TOC value in raffinate #2 was 289.7 mg / L. The TOC value in back-extraction solution #1 was 283.9 mg / L, and the TOC value in raffinate #2 was 237.0 mg / L.

[0118] As can be seen from the above embodiments, the lithium extraction resin provided by the present invention has almost no solvent loss when used for the recovery of lithium from lithium-containing liquids, and at the same time avoids the environmental problems caused by the volatilization of organic solvents.

[0119] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. Other embodiments can be obtained based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A lithium extraction resin, characterized in that, It includes a resin and an ion exchanger distributed in the resin; the ion exchanger is an alkyl salicylate ester. The lithium extraction resin is a porous spherical or near-spherical material with a particle size of 100-200 mesh. The lithium extraction resin contains 10-60% by mass of ion exchanger. The method for preparing the lithium extraction resin includes the following steps: The monomer, ion exchanger, crosslinking agent, initiator, and porogen are first mixed to obtain an organic phase; the ion exchanger is an alkyl salicylic acid ester. The dispersant, surfactant, and water are mixed in a second phase to obtain an aqueous phase. The organic phase and the aqueous phase are mixed for the third time to obtain a reaction solution; The reaction solution is subjected to a polymerization reaction to obtain the lithium extraction resin.

2. The lithium extraction resin according to claim 1, characterized in that, The resin is polystyrene resin; The alkyl salicylate includes one or more of octyl salicylate, propyl salicylate, butyl salicylate, pentyl salicylate, and hexyl salicylate.

3. The lithium extraction resin according to claim 1, characterized in that, The lithium extraction resin has a pore volume of 2 mL / g or more and a specific surface area of ​​500 m². 2 / g or more, with an average pore size of 10nm or more.

4. The method for preparing the lithium extraction resin according to any one of claims 1 to 3, characterized in that, Includes the following steps: The monomer, ion exchanger, crosslinking agent, initiator, and porogen are first mixed to obtain an organic phase; the ion exchanger is an alkyl salicylic acid ester. The dispersant, surfactant, and water are mixed in a second phase to obtain an aqueous phase. The organic phase and the aqueous phase are mixed for the third time to obtain a reaction solution; The reaction solution is subjected to a polymerization reaction to obtain the lithium extraction resin.

5. The preparation method according to claim 4, characterized in that, The monomer is styrene; The crosslinking agent is divinylbenzene; The initiator is benzoyl peroxide, azobisisobutyronitrile, cumene hydroperoxide, or lauroyl peroxide; The pore-forming agent is sodium thiocyanate, sodium bicarbonate, sodium carbonate, n-butyl ether, or toluene; The dispersant is gelatin or polyvinyl alcohol; The surfactant is sodium dodecyl sulfonate or Triton.

6. The preparation method according to claim 4 or 5, characterized in that, The volume ratio of the monomer to the crosslinking agent is 1:0.5~1.5; The volume ratio of the monomer to the reaction solution is 1:10~20; The ion exchanger in the organic phase has a mass percentage content of 10-60%.

7. The application of the lithium extraction resin according to any one of claims 1 to 3 or the lithium extraction resin obtained by the preparation method according to any one of claims 4 to 6 in lithium recovery.

8. A method for recovering lithium from a lithium-containing liquid, characterized in that, Includes the following steps: The lithium-containing liquid is passed through a lithium extraction resin for adsorption, resulting in an adsorption tail liquid and a lithium-rich resin; the lithium extraction resin is the lithium extraction resin according to any one of claims 1 to 3 or the lithium extraction resin obtained by the preparation method according to any one of claims 4 to 6. The acid solution is passed into the lithium-rich resin to desorb the lithium and obtain a lithium desorption solution.

9. The recycling method according to claim 8, characterized in that, The lithium concentration in the lithium-containing solution is 0.05~10 g / L; the flow rate of the lithium-containing solution is 2~5 BV / h. The ratio of lithium concentration in the adsorption tail liquid to lithium concentration in the lithium-containing feed liquid is 1:10~100; adsorption stops when the lithium concentration in the adsorption tail liquid reaches 0.005~1g / L.

10. The recycling method according to claim 8, characterized in that, The acid solution includes one or more of hydrochloric acid solution, nitric acid solution, and sulfuric acid solution; the hydrogen ion concentration of the acid solution is 0.05~6 mol / L; The flow rate of the acid solution is 0.5~2 BV / h.