A system and method for selectively extracting lithium from a lithium-containing high-salinity water

Abstract

The present application relates to the technical field of enrichment and extraction of rare metal lithium, and particularly relates to a system and method for selectively extracting lithium from lithium-containing high-salinity water. The system for selectively extracting lithium from lithium-containing high-salinity water comprises a lithium-containing high-salinity water selective extraction unit, electrodes arranged on both sides of the lithium-containing high-salinity water selective extraction unit, and an electrode chamber arranged between the lithium-containing high-salinity water selective extraction unit and the electrodes. The lithium-containing high-salinity water selective lithium extraction system can selectively adsorb lithium ions in lithium-containing high-salinity water by using an adsorbent in the adsorption chamber without an external electric field, and can make the lithium ions desorb and regenerate the adsorbent under an external electric field. Through the coupling of the two processes, the lithium ions can be cyclically enriched and concentrated, the desorption efficiency of the lithium ions and the lithium content of the desorption solution can be significantly improved while selectively extracting lithium from the lithium-containing high-salinity water, and the lithium concentration cost of the subsequent desorption solution can be greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of enrichment and extraction technology of rare metal lithium, specifically to a system and method for selective lithium extraction from high-salt water containing lithium. Background Technology

[0002] With the rapid development of the global new energy industry, the demand for lithium, as a crucial component of power batteries, is constantly increasing. Lithium exists in nature primarily in two forms: one is as lithium ore in lithium-bearing rocks such as spodumene and lepidolite; the other is as lithium ions in salt lake brines, underground brines, seawater, and lithium battery recovery leachates. Statistics show that approximately 60-70% of lithium ore is stored in brines, indicating a huge potential for brine-type lithium resources and a long-term, stable source of lithium. Therefore, selective lithium extraction from highly saline environments such as salt lake brines has become crucial for lithium resource development.

[0003] Currently, there are many methods for extracting lithium from high-salinity brine, mainly including chemical precipitation, ion exchange / adsorption, extraction, electrodialysis, and membrane separation. Among these, precipitation is the oldest method, and it is a mature, simple, and reliable process. However, this method is less adaptable to brines with high concentrations of alkaline earth metal ions and low lithium ion concentrations. In addition, high-salinity lithium-containing brine generally contains large amounts of sodium (Na). + K + Mg 2+ Ca 2+ and Cl - SO4 2- Characterized by impurities such as B and a high magnesium-to-lithium ratio, conventional methods such as chemical precipitation, extraction, electrodialysis, and membrane separation all suffer from low lithium recovery rates, high operating costs, and difficulty in long-term stable operation. Ion exchange / adsorption methods, on the other hand, face challenges such as low desorption efficiency, low lithium content in the desorption solution, and high costs associated with desorption solution concentration.

[0004] Therefore, there is no publicly available record in the existing technology on how to further improve the lithium-ion desorption efficiency of high-salt lithium extraction while simultaneously solving the problems of low lithium content in the desorption solution and high concentration cost of the desorption solution. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defects of existing lithium extraction methods, such as low desorption efficiency, large consumption of desorption water, low lithium content in desorption solution, and high cost of desorption solution concentration. The present invention provides a system and method for selective lithium extraction from high-salt lithium-containing water to solve the above problems.

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

[0007] A system for selective lithium extraction from lithium-containing high-salt water includes a lithium-containing high-salt water selective extraction unit, electrodes respectively disposed on both sides of the lithium-containing high-salt water selective extraction unit, and an electrode chamber disposed between the lithium-containing high-salt water selective extraction unit and the electrodes.

[0008] The lithium-containing high-salt selective lithium extraction unit includes a membrane stack consisting of alternating cation exchange membranes (CM) and anion exchange membranes (AM) arranged in an electric field, wherein the cation exchange membranes and anion exchange membranes form an adsorption chamber, and the anion exchange membranes and another adjacent cation exchange membrane form a concentration chamber.

[0009] The electrode includes an anode and a cathode. The anode is located near the outermost anion exchange membrane of the lithium-containing high-salt water selective extraction unit, and the cathode is located near the outermost cation exchange membrane of the lithium-containing high-salt water selective extraction unit. The adsorption chamber of the lithium-containing high-salt water selective extraction unit is filled with a lithium-ion selective adsorbent.

[0010] Preferably, the system for selective lithium extraction from lithium-containing high-salt water further includes:

[0011] The circuit supplies DC power to the electrodes through a regulated DC power supply;

[0012] Pipelines are connected to different circulating pumps to provide polar water, lithium-containing high-salt water, and clean water to the polar chamber, concentration chamber, and adsorption chamber, respectively.

[0013] A lithium-containing high-salt water storage tank is connected to the adsorption chamber via pipeline;

[0014] A clear water storage tank, connected to the concentration chamber and adsorption chamber, is used to store clear water and is pumped through a circulation pump for cleaning the adsorbent.

[0015] A lithium recovery liquid storage tank, connected to a concentration chamber, is used to store high-lithium clean water for recovery.

[0016] The polar water tank is connected to the polar chamber and is used to store polar water.

[0017] A circulating pump, installed in the pipeline, provides power for the transport of polar water, lithium-containing high-salt water, and clean water;

[0018] A regulated DC power supply, connected to the electrodes via a circuit, is used to provide electrical energy to the electrodes;

[0019] Control valves, online sensors, and intelligent control systems are used to automatically determine the processing status and adjust the opening and closing of the circulation pump and electrodes.

[0020] Preferably, the lithium-ion selective adsorbent includes at least one of aluminum-based molecular sieve adsorbents, titanium-based ion sieve adsorbents, manganese-based ion sieve adsorbents, and doped ion sieve adsorbents.

[0021] And / or, the packing thickness of the lithium-ion selective adsorbent is 1-100 mm;

[0022] And / or, the cross-sectional area of ​​the lithium-ion selective adsorbent is the same as the effective area of ​​the cation exchange membrane and the anion exchange membrane;

[0023] And / or, the number of adsorption chambers in the membrane stack of the lithium-containing high-salt water selective extraction unit is 1-60.

[0024] The present invention also provides a method for selective lithium extraction from high-salt water containing lithium, comprising:

[0025] 1) Pretreatment of high-lithium-containing saline solution;

[0026] 2) Without applying an electric field, the lithium-containing high-salt water pretreated in step 1) is transported to the adsorption chamber, where lithium ions in the lithium-containing high-salt water are adsorbed by a lithium-ion selective adsorbent, while clean water is simultaneously transported to the adjacent concentration chamber to maintain the pressure balance between the different chambers.

[0027] 3) Once the lithium-ion selective adsorbent is saturated with lithium ions, all compartments are rinsed with clean water.

[0028] 4) Apply an electric field to the membrane stack to desorb the adsorbed lithium ions and regenerate the adsorbent. The desorbed lithium ions enter the concentration chamber through the cation exchange membrane under the action of the applied electric field, while the chloride ions in the adsorption chamber enter the adjacent concentration chamber through the anion exchange membrane to maintain charge balance and form high-lithium water in the concentration chamber. Obtain the high-lithium water obtained in the concentration chamber.

[0029] 5) High-lithium water is circulated and concentrated to obtain a high-concentration lithium concentrate.

[0030] Preferably, the pretreatment method is at least one of chemical precipitation, precision filtration, membrane separation, activated carbon adsorption, electrodeposition, and advanced oxidation;

[0031] And / or, the pretreatment reduces the concentration of organic matter in lithium-containing high-salt water to below 100 mg / L, and the removal rate of colloids and suspended solids is ≥90%;

[0032] And / or, the concentration of lithium ions in the high-concentration lithium concentrate is 0.5 g / L or higher, preferably 0.5-6 g / L.

[0033] Preferably, the high-concentration lithium-containing concentrate is further concentrated and a precipitant is added to recover lithium products.

[0034] Preferably, the secondary concentration process is a membrane-based concentration process and / or a thermal concentration process;

[0035] And / or, the lithium concentration of the solution after the secondary concentration treatment is 10-30 g / L;

[0036] And / or, the precipitant is at least one of Na2CO3, (NH4)2CO3 and NaF;

[0037] And / or, the lithium-precipitated solution is returned to the preceding concentration unit for further concentration before lithium precipitation and recovery.

[0038] Preferably, the membrane combination concentration process is reverse osmosis and / or electrodialysis;

[0039] And / or, the thermal concentration process is steam mechanical recompression and / or multi-effect evaporation.

[0040] Preferably, the flow rate of the lithium-containing high-salt water in the membrane stack is 0.01-5.0 m / s. 3 / h;

[0041] And / or, the adsorption rate of lithium in lithium-containing high-salt water by the membrane stack in a single batch is 5%-90%;

[0042] And / or, the residual lithium ion concentration in the lithium-containing high-salt water after the adsorption treatment is ≤50mg / L;

[0043] And / or, the flow rate of the wash is 1-10 times that of the lithium-containing high-salt water flow rate.

[0044] Preferably, when an external electric field is applied to the membrane stack, the voltage between a single pair of cation exchange membranes and anion exchange membranes is 0.1-10.0V.

[0045] And / or, the desorption time of the lithium-ion selective adsorbent in the membrane stack adsorption chamber is 10-120 min.

[0046] In this invention, when there are ≥2 types of lithium-ion selective adsorbents, layered filling or uniform mixing before filling is employed; the cation exchange membrane is effective against water molecules and Cl-. - The ions exhibit low permeability; the anion exchange membrane is sensitive to water molecules and Li + Ions have low permeability.

[0047] The technical solution of this invention has the following advantages:

[0048] 1. A system for selective lithium extraction from high-salt lithium-containing brine, comprising a selective extraction unit for high-salt lithium-containing brine, electrodes respectively disposed on both sides of the selective extraction unit, and an electrode chamber disposed between the selective extraction unit and the electrodes; the selective extraction unit for high-salt lithium-containing brine includes a membrane stack consisting of alternating cation exchange membranes and anion exchange membranes disposed within an electric field, wherein the cation exchange membranes and anion exchange membranes form an adsorption chamber, and the anion exchange membrane forms a concentration chamber with another adjacent cation exchange membrane; the electrodes include an anode and a cathode, the anode being disposed near the outermost anion exchange membrane of the selective extraction unit for high-salt lithium-containing brine, and the cathode being disposed near the outermost cation exchange membrane of the selective extraction unit for high-salt lithium-containing brine; the adsorption chamber of the selective extraction unit for high-salt lithium-containing brine is filled with a lithium-ion selective adsorbent. The selective lithium extraction system for high-salt lithium-containing brine of the present invention can achieve highly selective lithium extraction from high-salt lithium-containing brine, while significantly improving lithium-ion desorption efficiency and significantly increasing the lithium content in the solution after elution treatment, thereby greatly reducing the lithium concentration cost of the subsequent desorption solution.

[0049] 2. The method for selective lithium extraction from high-salinity lithium-containing brine of the present invention utilizes the selective adsorption of lithium ions by an adsorbent when no electric field is applied. When an external electric field is applied, lithium ions undergo electro-desorption, and the adsorbent is regenerated. The coupling of these two processes achieves efficient recovery of lithium resources from high-salinity lithium-containing brine. This not only solves the problems of poor selectivity, low recovery rate, and severe scaling and membrane fouling inherent in traditional electrodialysis for lithium extraction from high-salinity brine, but also overcomes the problems of low lithium desorption efficiency, incomplete adsorbent regeneration, high consumption of clean water resources, and high concentration costs associated with ion exchange methods for lithium extraction. It promotes the efficient recovery and utilization of lithium resources from high-salinity brine, offering both environmental and economic benefits. Attached Figure Description

[0050] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0051] Figure 1 This is a schematic diagram of the selective lithium extraction system in high-salt lithium-containing water in Embodiment 1 of the present invention;

[0052] Figure 2 This is a process flow diagram of selective lithium extraction from lithium-containing high-salt water in Embodiment 1 of the present invention;

[0053] Figure 3This is a schematic diagram of the adsorption process without an external electric field in Embodiment 1 of the present invention.

[0054] Figure 4 This is a schematic diagram of the principle of lithium-ion desorption treatment under an external electric field in Embodiment 1 of the present invention. Detailed Implementation

[0055] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0056] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0057] Example 1

[0058] This embodiment provides a system for selective lithium extraction from high-salt water containing lithium, such as... Figure 1As shown, the system includes a lithium-containing high-salt water selective extraction unit, circuitry, piping, brine storage tank, clear water storage tank, lithium recovery liquid storage tank, electrode water tank, circulation pumps (including brine circulation pump, clear water circulation pump, lithium recovery liquid circulation pump, and electrode water circulation pump), a regulated DC power supply, control valves, online sensors, and an intelligent control system. The lithium-containing high-salt water selective extraction unit includes several pairs of cation exchange membranes and anion exchange membranes, an anode (titanium-coated electrode), and a cathode (ordinary titanium plate electrode). These pairs of cation exchange membranes and anion exchange membranes are arranged sequentially between the anode and cathode. The anode is positioned on the outermost side of the sequential arrangement where the anion exchange membrane is located, and the cathode is positioned on the outermost side of the sequential arrangement where the cation exchange membrane is located. Electrode chambers are formed between the anode and anion exchange membrane, and between the cathode and cation exchange membrane. Each pair of cation exchange membranes and anion exchange membrane forms an adsorption chamber, which is filled with an aluminum-based molecular sieve lithium-ion selective adsorbent with a filling thickness of 10 mm. A concentration chamber is formed between adjacent pairs of cation and anion exchange membranes. In this embodiment, 10 pairs of cation and anion exchange membranes are arranged side by side to form a membrane stack. The anode is located near the outermost anion exchange membrane of the membrane stack, and the cathode is located near the outermost cation exchange membrane of the membrane stack. Between the anode and cathode and the outermost ion exchange membrane of the membrane stack, there is also an electrode chamber through which electrode water flows. The anode and cathode are connected to a regulated DC power supply through a circuit. In the brine storage tank, brine flows through pipelines and the various adsorption chambers of the membrane stack, powered by a brine circulation pump, before returning to the brine storage tank. In the clear water storage tank, clear water flows through pipelines and the various adsorption chambers of the membrane stack, powered by a clear water circulation pump, before returning to the clear water storage tank to clean the adsorbent. In the lithium recovery solution storage tank, lithium recovery solution flows through pipelines and the various concentration chambers of the membrane stack, powered by a lithium recovery solution circulation pump, before returning to the lithium recovery solution storage tank to continuously enrich the lithium concentration in the clear water. The electrode water storage tank is connected to the electrode chambers on both sides of the membrane stack through pipelines and an electrode water circulation pump on the pipelines, providing electrode water. The electrode water (LiCl solution) is enriched during circulation to form a high-concentration lithium-containing concentrate. After the electrode water is replaced, the high-concentration lithium-containing concentrate undergoes a secondary concentration treatment. Simultaneously, the circulation pump and electrode are automatically adjusted to start and stop based on the treatment status using control valves, online sensors, and an intelligent control system. This embodiment uses low-permeability, anti-fouling cation exchange membranes and anion exchange membranes. The cation exchange membrane is effective against water molecules and Cl-. - Ions have low permeability; anion exchange membranes are less permeable to water molecules and Li. + Ions have low permeability. The effective area of ​​a single ion exchange membrane is 50 cm². 2 The loading area of ​​the lithium-ion selective adsorbent is the same as the effective area of ​​the ion exchange membrane, and the effective area of ​​the electrode is also the same as the effective area of ​​the ion exchange membrane.

[0059] In this embodiment, the main ionic composition of the lithium-containing high-salt water (brine) used is as follows: 0.56 g / L Li+ 98.25g / L Na + 11.67g / LK + 17.26 g / L Mg 2+ 0.42 g / L Ca 2+ 24.81 g / L SO4 2- 0.85g / LB 3+ .

[0060] The lithium-containing high-salt water selective lithium extraction system described in this embodiment is used to treat the aforementioned lithium-containing high-salt water (process flow is as follows). Figure 2 The specific steps (as shown) are as follows:

[0061] 1) A precision filter is used to filter lithium-containing high-salt water, reducing the concentration of organic matter in the lithium-containing high-salt water to below 20 mg / L, and the removal rate of colloids and suspended solids is ≥90%;

[0062] 2) Without applying an electric field, the lithium-containing brine filtered in step 1) is pumped to the adsorption chamber via a circulating pump. A lithium-ion selective adsorbent adsorbs lithium ions from the brine. Simultaneously, clean water is pumped into the adjacent concentration chamber via a circulating pump to maintain pressure balance between the different chambers. The flow rate of the solution in each chamber is 50 L / h. The schematic diagram for adsorption treatment without an external electric field is shown below. Figure 3 As shown;

[0063] 3) After running continuously for 120 minutes without an electric field, the adsorption chamber solution is switched to clean water and continuously rinsed for 10 minutes at a flow rate of 50 L / h to thoroughly remove the residual high saline solution in the adsorption chamber.

[0064] 4) After cleaning the membrane stack in step 3), an electric field is applied. The adsorption chamber is switched to clean water, and the concentration chamber is switched to low-lithium clean water (clean water for the first cycle, and low-lithium clean water from the lithium recovery solution storage tank for subsequent cycles). These cycles are driven by circulation pumps through different compartments. The membrane stack voltage is adjusted to a range of 10-100V using a DC potentiostat, and the membrane stack current is controlled at 0.5A. The system runs continuously for 30 minutes to ensure the complete release of adsorbed lithium ions from the adsorbent. The schematic diagram of lithium ion desorption under an applied electric field is shown below. Figure 4 As shown;

[0065] 5) After repeated static adsorption without electricity and regeneration with electricity, while the lithium-containing solution is continuously circulated and concentrated throughout the process, after 20 consecutive cycles, the Li in the lithium recovery solution storage tank... + With an ion concentration of 3.51 g / L, the recovery rate of lithium ions in high-salt water containing lithium in a single-batch adsorption-regeneration process in the membrane stack was 26.5%, and the desorption rate of lithium ions in the adsorbent under the action of an electric field was about 91.5%.

[0066] 6) When the lithium-containing solution in the lithium recovery liquid storage tank contains Li + When the ion concentration is 5.96 g / L, further concentration is achieved using a combination of electrodialysis and reverse osmosis membranes, resulting in a lithium-containing concentrate with a lithium concentration of 13.5 g / L or even higher. The concentrate is then heated to 90°C, and Na₂CO₃ precipitant is added at a lithium ion to precipitant molar ratio of 1:1.5 to further concentrate the lithium content in the concentrate. + After the ions are converted into Li₂CO₃, they are recovered. The purified water produced by reverse osmosis is returned for washing, and the residual solution after chemical precipitation is returned to conventional electrodialysis for further concentration and lithium precipitation recovery.

[0067] Example 2

[0068] The difference between this embodiment and Embodiment 1 is that the lithium-ion selective adsorbent is a manganese-based molecular sieve adsorbent and a titanium-based ion sieve adsorbent, with a mass ratio of 1:1. The two lithium-ion selective adsorbents are uniformly packed into the lithium extraction system adsorption chamber in a layered manner. Other conditions are the same as in Embodiment 1. In this embodiment, the desorbed lithium-containing solution is continuously circulated and concentrated throughout the process. After 20 consecutive cycles, the Li in the lithium recovery liquid storage tank... + With an ion concentration of 4.39 g / L, the recovery rate of lithium ions in high-salt water containing lithium in a single-batch adsorption-regeneration process in the membrane stack was 28.5%, and the desorption rate of lithium ions in the adsorbent was 93% under the action of an electric field.

[0069] Example 3

[0070] The difference between this embodiment and Embodiment 2 is that the two lithium-ion selective adsorbents are uniformly mixed before filling; other conditions are the same as in Embodiment 2. In this embodiment, the desorbed lithium-containing solution is continuously circulated and concentrated throughout the process. After 20 consecutive cycles, the Li in the lithium recovery solution storage tank... + With an ion concentration of 5.12 g / L, the recovery rate of lithium ions in high-salt water containing lithium in a single-batch adsorption-regeneration process in the membrane stack was 22.4%, and the desorption rate of lithium ions in the adsorbent was 92% under the action of an electric field.

[0071] Comparative Example 1

[0072] The difference between this comparative example and Example 1 is that no external electric field is applied during lithium ion desorption; only water is passed through for elution. Other conditions are the same as in Example 1. In this comparative example, the desorbed lithium-containing solution is continuously circulated and concentrated throughout the process. After 20 consecutive cycles, the Li in the concentrate tank... + The ion concentration was 0.65 g / L, and the recovery rate of lithium ions from high saline water in a single adsorption-regeneration process was 21.6%, while the desorption rate of lithium ions in the adsorbent was 41.5% without the application of an electric field.

[0073] Comparative Example 2

[0074] This comparative example uses the same lithium-ion selective adsorbent and filling conditions as Example 2. The difference is that no external electric field is applied during lithium-ion desorption; only water is purged for elution. Other conditions remain the same as in Example 2. Throughout the process, the lithium-containing solution in this comparative example is continuously circulated and concentrated. After 20 consecutive cycles, the Li in the lithium recovery solution storage tank... + With an ion concentration of 3.2 g / L, the recovery rate of lithium ions from lithium-containing high-salt water in a single-batch adsorption-regeneration process in the membrane stack was 20.5%, and the desorption rate of lithium ions in the adsorbent was 37.5% without the application of an electric field.

[0075] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A system for selective lithium extraction from high-salt lithium-containing brine, characterized in that, It includes a lithium-containing high-salt water selective extraction unit, electrodes respectively disposed on both sides of the lithium-containing high-salt water selective extraction unit, and an electrode chamber disposed between the lithium-containing high-salt water selective extraction unit and the electrodes; The lithium-containing high-salt selective lithium extraction unit is composed of a membrane stack consisting of alternating cation exchange membranes and anion exchange membranes arranged in an electric field. The cation exchange membrane and the anion exchange membrane form an adsorption chamber, and the anion exchange membrane and another adjacent cation exchange membrane form a concentration chamber. The electrode includes an anode and a cathode. The anode is located near the outermost anion exchange membrane of the lithium-containing high-salt water selective extraction unit, and the cathode is located near the outermost cation exchange membrane of the lithium-containing high-salt water selective extraction unit. The adsorption chamber of the lithium-containing high-salt water selective extraction unit is filled with a lithium-ion selective adsorbent. The system for selective lithium extraction from lithium-containing high-salt water also includes: The circuit supplies DC power to the electrodes through a regulated DC power supply; Pipelines are connected to different circulating pumps to provide polar water, lithium-containing high-salt water, and clean water to the polar chamber, concentration chamber, and adsorption chamber, respectively. A lithium-containing high-salt water storage tank is connected to the adsorption chamber via pipeline; A clear water storage tank, connected to the concentration chamber and adsorption chamber, is used to store clear water and is pumped through a circulation pump for cleaning the adsorbent. A lithium recovery liquid storage tank, connected to a concentration chamber, is used to store high-lithium clean water for recovery. The polar water tank is connected to the polar chamber and is used to store polar water. A circulating pump, installed in the pipeline, provides power for the transport of polar water, lithium-containing high-salt water, and clean water; A regulated DC power supply, connected to the electrodes via a circuit, is used to provide electrical energy to the electrodes; Control valves, online sensors, and intelligent control systems are used to automatically determine the processing status and adjust the opening and closing of the circulation pump and electrodes.

2. The system according to claim 1, characterized in that, The lithium-ion selective adsorbent includes at least one of aluminum-based molecular sieve adsorbents, titanium-based ion sieve adsorbents, and manganese-based ion sieve adsorbents. And / or, the packing thickness of the lithium-ion selective adsorbent is 1-100 mm; And / or, the number of adsorption chambers in the membrane stack of the lithium-containing high-salt water selective extraction unit is 1-60.

3. A method for selective lithium extraction from high-lithium brine, characterized in that, include: 1) Pretreatment of high-lithium-containing saline solution; 2) Without applying an electric field, the lithium-containing high-salt water pretreated in step 1) is transported to the adsorption chamber, where lithium ions in the lithium-containing high-salt water are adsorbed by a lithium-ion selective adsorbent, while clean water is simultaneously transported to the adjacent concentration chamber to maintain the pressure balance between the different chambers. 3) Once the lithium-ion selective adsorbent is saturated with lithium ions, all compartments are rinsed with clean water. 4) Apply an electric field to the membrane stack to desorb the adsorbed lithium ions and regenerate the adsorbent. The desorbed lithium ions enter the concentration chamber through the cation exchange membrane under the action of the applied electric field, while the chloride ions in the adsorption chamber enter the adjacent concentration chamber through the anion exchange membrane to maintain charge balance and form high-lithium water in the concentration chamber. Obtain the high-lithium water obtained in the concentration chamber. 5) High-lithium water is circulated and concentrated to obtain a high-concentration lithium-containing concentrate; The system for selective lithium extraction from lithium-containing high-salt water as described in claim 1 or 2.

4. The method according to claim 3, characterized in that, The pretreatment method is at least one of chemical precipitation, precision filtration, membrane separation, activated carbon adsorption, electrodeposition, and advanced oxidation. And / or, the pretreatment reduces the concentration of organic matter in lithium-containing high-salt water to below 100 mg / L, and the removal rate of colloids and suspended solids is ≥90%; And / or, the concentration of lithium ions in the high-concentration lithium concentrate is 0.5 g / L or higher.

5. The method according to claim 4, characterized in that, The concentration of lithium ions in the high-concentration lithium concentrate is 0.5-6 g / L.

6. The method according to claim 3 or 4, characterized in that, The high-concentration lithium-containing concentrate is further concentrated and a precipitant is added to recover lithium products.

7. The method according to claim 6, characterized in that, The secondary concentration process is a membrane combination concentration process and / or a thermal concentration process. And / or, the lithium concentration of the solution after the secondary concentration treatment is 10-30 g / L; And / or, the precipitant is at least one of Na2CO3, (NH4)2CO3 and NaF; And / or, the lithium-precipitated solution is returned to the preceding concentration unit for further concentration before lithium precipitation and recovery.

8. The method according to claim 7, characterized in that, The membrane combination concentration process is reverse osmosis and / or electrodialysis; And / or, the thermal concentration process is steam mechanical recompression and / or multi-effect evaporation.

9. The method according to claim 3 or 4, characterized in that, The flow rate of the lithium-containing high-salt water in the membrane stack is 0.01-5.0 m. 3 / h; And / or, the adsorption rate of the membrane stack for lithium in high-lithium saline water in a single batch is 5%-90%; And / or, the residual lithium ion concentration in the lithium-containing high-salt water after the adsorption treatment is ≤50 mg / L; And / or, the flow rate of the wash is 1-10 times that of the lithium-containing high-salt water flow rate.

10. The method according to claim 3 or 4, characterized in that, When an external electric field is applied to the membrane stack, the voltage between a single pair of cation exchange membranes and anion exchange membranes is 0.1-10.0 V; And / or, the desorption time of the lithium-ion selective adsorbent in the membrane stack adsorption chamber is 10-120 min.

Images