Device and method for extracting lithium by coupling an ion sieve adsorbent with bipolar membrane electrodialysis

Abstract

The present invention relates to the technical field of lithium extraction, and particularly to a device and method for coupling lithium extraction by an ion sieve adsorbent and bipolar membrane electrodialysis. By embedding the lithium ion sieve adsorbent into the acid chamber and the alkali chamber of the bipolar membrane electrodialysis device respectively to form a membrane package structure, the present invention realizes the organic combination of the adsorption method and the electrodialysis membrane separation method. When the power is on, the lithium ion sieve adsorbent in the alkali chamber is in the adsorption state, while the ion sieve in the acid chamber is not adsorbed. After a period of time, the lithium ion sieve in the alkali chamber is saturated with adsorption, and a large amount of acid is generated in the acid chamber. At this time, the power is cut off and the pipeline is "swapped". Only the liquid flows under the non-powered state. At this time, the lithium ion sieve adsorbent that has been saturated with adsorption in the alkali chamber is desorbed after being passed through the acid solution, and the ion sieve adsorbent that has not been adsorbed in the acid chamber is adsorbed after being passed through the alkali solution. A high-purity and high-concentration lithium-containing solution is obtained in the acid solution storage tank, improving the integration and efficiency of lithium extraction.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium extraction, and particularly to a device and method for coupling an ion sieve adsorbent with bipolar membrane electrodialysis for lithium extraction. Background Art

[0002] At present, the main methods for extracting lithium from salt lake brine include adsorption method, membrane separation method, precipitation method, extraction method, etc., but these methods all have certain limitations. Although the adsorption method has high selectivity and adsorption capacity, its recovery process needs to be carried out under specific conditions, and the operation difficulty is relatively large; although the electrodialysis membrane separation method is environmentally friendly and efficient, its energy consumption is high and the cost is expensive; the precipitation method has mature technology, but its selectivity for brine with a high magnesium-lithium ratio is poor; although the extraction method has excellent separation effect, the organic extraction solvent is easy to cause environmental pollution.

[0003] In the adsorption method, the commonly used adsorbents mainly include aluminum-based adsorbents, manganese-based lithium ion sieves, and titanium-based lithium ion sieves. Among them, manganese-based and titanium-based lithium ion sieves have become research hotspots due to their high selectivity for lithium, excellent adsorption capacity, regeneration performance, and high adsorption capacity. However, their adsorption and desorption processes need to be carried out in alkaline and acidic environments respectively, which limits their application scope.

[0004] The electrodialysis membrane separation method realizes the directional migration of Li + through the action of an electric field, and realizes the concentration and dilution of Li + in a specific area. Traditional electrodialysis technology generates Li2CO3 by adding soda ash to the "concentrated chamber", but if LiOH required by the lithium battery industry is to be obtained, further treatment is still needed. Summary of the Invention

[0005] The purpose of the present invention is to propose a device and method for coupling an ion sieve adsorbent with bipolar membrane electrodialysis for lithium extraction in view of the above deficiencies of the prior art.

[0006] The first object of the present invention is to provide a device for coupling an ion sieve adsorbent with bipolar membrane electrodialysis for lithium extraction, including a three-compartment bipolar membrane electrodialysis device and a liquid storage device: the three-compartment bipolar membrane electrodialysis device includes a cathode chamber, an anode chamber, and at least one membrane unit, the membrane unit is arranged between the cathode chamber and the anode chamber, the membrane unit includes an alkali chamber, a dilute chamber, and an acid chamber arranged in sequence along the direction from the cathode chamber to the anode chamber, the alkali chamber and the dilute chamber are at least separated from each other by a cation exchange membrane, the dilute chamber and the acid chamber are at least separated from each other by an anion exchange membrane, and the cathode chamber and the alkali chamber, the anode chamber and the acid chamber are at least separated from each other by a bipolar membrane; lithium ion sieve adsorbents are provided in both the alkali chamber and the acid chamber, and the lithium ion sieve adsorbent adsorbs lithium under alkaline conditions and desorbs lithium under acidic conditions;

[0007] The liquid storage device includes a fresh chamber storage tank, an alkali solution storage tank, an acid solution storage tank, and an electrode solution storage tank; the fresh chamber storage tank forms a circulation pipeline with the fresh chamber through a first pipeline assembly, and the electrode solution storage tank forms a circulation pipeline with the cathode chamber and the anode chamber through a second pipeline.

[0008] In the initial state, a lithium-containing solution is added to the fresh chamber storage tank and the alkali solution storage tank, pure water is added to the acid solution storage tank, and electrode solution is added to the electrode solution storage tank.

[0009] The alkali solution storage tank forms a circulation pipeline with the alkali chamber or the acid chamber through a third pipeline assembly, and the acid solution storage tank forms a circulation pipeline with the acid chamber or the alkali chamber through a fourth pipeline assembly.

[0010] Further, the lithium ion sieve adsorbent is prepared by the following method: a slurry containing ion sieve powder is coated on a support mesh, and then a coating layer is formed on the surface of the support mesh by gel crosslinking.

[0011] Further, the support mesh is a nylon mesh sieve, a polyester mesh sieve, or a metal mesh material.

[0012] Further, the ion sieve powder is a manganese-based ion sieve powder, a titanium-based ion sieve powder, or a composite metal-based ion sieve powder.

[0013] Further, it includes a plurality of membrane units, and the plurality of membrane units are connected in series or in parallel.

[0014] Further, the slurry also includes binder powder and N,N-dimethylformamide, and the binder powder includes polyvinyl chloride and polyacrylonitrile with a mass ratio of 9-2:1.

[0015] Further, the first pipeline assembly, the second pipeline assembly, the third pipeline assembly, and the fourth pipeline assembly all include a pipeline and a circulation pump arranged on the pipeline.

[0016] The second object of the present invention is a method for extracting lithium by coupling a lithium ion sieve adsorbent with bipolar membrane electrodialysis using the above device.

[0017] Further, the specific method is as follows:

[0018] In the initial state, a lithium-containing solution is added to the fresh chamber storage tank and the alkali solution storage tank, pure water is added to the acid solution storage tank, and electrode solution is added to the electrode solution storage tank; the alkali solution storage tank forms a circulation pipeline with the alkali chamber through a third pipeline assembly, and the acid solution storage tank forms a circulation pipeline with the acid chamber through a fourth pipeline assembly.

[0019] Start the bipolar membrane electrodialysis device. Lithium ions are adsorbed in the alkali chamber, and an acidic environment is generated in the acid chamber. When the adsorption in the alkali chamber is saturated and the pH in the acid chamber drops to the preset threshold, turn off the bipolar membrane electrodialysis device and switch the pipeline. The alkali liquid storage tank forms a circulation pipeline with the acid chamber through the third pipeline assembly, and the acid liquid storage tank forms a circulation pipeline with the alkali chamber through the fourth pipeline assembly, so that the acid liquid flows through the alkali chamber to desorb lithium ions, and the alkali liquid flows through the acid chamber for adsorption. Repeat the above steps to continuously collect the high-concentration lithium-containing solution from the acid liquid storage tank.

[0020] Furthermore, the lithium-containing solution is obtained by filtering, impurity removal or concentration treatment of at least one of the lithium-containing solution in the salt lake, seawater, oilfield water, geothermal water, and industrial wastewater.

[0021] Furthermore, the preset threshold of the pH in the acid chamber is 1-2.

[0022] The device for extracting lithium by coupling an ion sieve adsorbent and bipolar membrane electrodialysis according to the present invention integrates the ion sieve adsorbent into the acid chamber and the alkali chamber of the bipolar membrane electrodialysis device respectively to form a membrane package structure, realizing the organic combination of the adsorption method and the electrodialysis membrane separation method. The present invention makes full use of the characteristics of the acid chamber and the alkali chamber of the bipolar membrane electrodialysis: the acidic environment in the acid chamber is beneficial to the elution of Li + in the ion sieve adsorbent, while the alkali chamber can effectively concentrate the lithium-containing solution and increase its alkalinity, thereby enhancing the adsorption performance of the ion sieve adsorbent. In the energized state, the ion sieve adsorbent in the alkali chamber is in the adsorption state, while the ion sieve in the acid chamber is not adsorbed. After a period of time, the ion sieve in the alkali chamber is saturated with adsorption, and a large amount of acid is generated in the acid chamber. At this time, the power is cut off and the pipeline is "swapped". Only the liquid flows in the non-energized state. At this time, the ion sieve adsorbent that has been saturated with adsorption in the alkali chamber is desorbed after the acid liquid is introduced, and the ion sieve adsorbent that has not been adsorbed in the acid chamber is adsorbed after the alkali liquid is introduced. A high-purity and high-concentration lithium-containing solution is obtained in the acid liquid storage tank, improving the integration degree and efficiency of lithium extraction, and the obtained lithium-containing solution is lithium hydroxide, avoiding secondary treatment.

[0023] The high flow rate of electrodialysis has relatively high requirements for the structural stability and mechanical strength of the ion sieve. Therefore, the present invention further prepares an adsorption material with high adsorption capacity and high mechanical strength by forming the ion sieve with PVC / PAN, combining it with a support mesh and then coating it with a gel material. The combination of this material and the bipolar membrane electrodialysis technology forms an adsorbent-electrodialysis system, which has excellent extraction effects on low-grade lithium-containing solutions. This technology has the advantages of high energy utilization rate, high product purity, and good material recyclability, showing broad application prospects.

[0024] The invention provides a method with low cost, environmental friendliness, good stability, high lithium extraction efficiency, which can reduce the cost brought by the low initial concentration of lithium-containing solution and the regulation of pH during the adsorption and desorption process of lithium ion sieve. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 FIG. 6 is a schematic structural diagram of a device for extracting lithium by coupling an ion sieve adsorbent and bipolar membrane electrodialysis of the present invention in the energized state and the de-energized state;

[0026] Figure 2 FIG. 10 is the adsorption isotherm curve of ion sieves in different forms;

[0027] FIG. 3 shows the change of lithium ion concentration in the acid chamber;

[0028] FIG. 4 shows the change of lithium ion concentration in the alkali chamber and the dilute chamber. DETAILED DESCRIPTION OF THE INVENTION

[0029] The following are specific embodiments of the present invention in combination with the accompanying drawings, and the technical solutions of the present invention will be further described, but the present invention is not limited to these embodiments.

[0030] Example 1

[0031] Preparation of Manganese-based Lithium Ion Sieve Adsorbent

[0032] ① Weigh polyvinyl chloride (PVC) and polyacrylonitrile PAN according to a mass ratio of 5:1 and mix them into a binder powder. Among them, PVC can improve the mechanical strength of the ion sieve, and PAN can improve the hydrophilicity of the ion sieve. Then add the binder powder to N,N-dimethylformamide (DMF) according to a mass ratio of 1:13.6, seal and stir for 8 h until the solution is clear and bubble-free. Finally, add the hydrothermally synthesized Li 1.6 Mn 1.6 O4 manganese-based ion sieve powder according to the ratio of binder powder: ion sieve powder: N,N-dimethylformamide = 1:4:13.6, and seal and stir for 8 h to form a black slurry.

[0033] ② Cut a certain area of 100-mesh nylon mesh sieve, lay it flat on a glass plate, and apply the black slurry on the nylon mesh sieve with a scraper. Among them, the nylon mesh sieve provides a structural support function, and then immerse it in water for 48 hours to form a nylon-PVC / PAN-ion sieve composite material, abbreviated as NPLMO.

[0034] ③ Prepare a 1% sodium alginate (SA) solution, immerse the formed NPLMO in the SA solution, and after taking it out, soak it in a 2% CaCl₂ solution for 48 h for cross-linking and forming. Here, SA acts as a coating layer to play a physical isolation role, obtaining a SNPLOM composite membrane-like lithium ion sieve adsorbent. The obtained lithium ion sieve adsorbent has good uniformity, high mechanical strength, and high capacity retention rate, which is 78% of the powder adsorption capacity.

[0035] Example 2

[0036] The adsorption performance of SNPLMO was tested, and the initial powdered Li 1.6 Mn 1.6 O₄ ion sieve was compared with the granular formed ion sieve particles.

[0037] The detailed operating conditions and treatment results are as follows:

[0038] Isothermal adsorption was carried out on three forms of Li 1.6 Mn 1.6 O₄: powder, film, and granular. First, pickling was carried out with 0.1 mol / L HCl. After pickling and drying, at 30 °C, isothermal adsorption was carried out in a lithium-containing solution with 200 ppm LiCl and the pH adjusted to 13 with KOH.

[0039] Figure 2 shows the adsorption isotherm curves of ion sieves in different forms. It can be seen that the adsorption rate and adsorption capacity of the composite membrane-like SNPLOM are comparable to those of the granular form, which is 78% of the powder adsorption capacity. This shows that adding nylon support material and SA coating layer has almost no effect on the adsorption performance of the ion sieve, and at the same time, it also improves the mechanical strength and the strength against water flow impact.

[0040] Example 3

[0041] As Figure 1 shown, a device for extracting lithium by coupling an ion sieve adsorbent with bipolar membrane electrodialysis includes a three-compartment bipolar membrane electrodialysis device and a liquid storage device: The three-compartment bipolar membrane electrodialysis device includes a cathode chamber, an anode chamber, and at least one membrane unit. The membrane unit is arranged between the cathode chamber and the anode chamber. The membrane unit includes an alkali chamber, a dilute chamber, and an acid chamber arranged in sequence along the direction from the cathode chamber to the anode chamber. The alkali chamber and the dilute chamber are at least separated from each other by a cation exchange membrane, and the dilute chamber and the acid chamber are at least separated from each other by an anion exchange membrane. The cathode chamber and the alkali chamber, and the anode chamber and the acid chamber are at least separated from each other by a bipolar membrane; Lithium ion sieve adsorbents are provided in both the alkali chamber and the acid chamber. The lithium ion sieve adsorbent adsorbs lithium under alkaline conditions and desorbs lithium under acidic conditions;

[0042] The liquid storage device includes a fresh chamber storage tank 1, an alkali solution storage tank 3, an acid solution storage tank 2, and an electrode solution storage tank 4; the fresh chamber storage tank 1 forms a circulation pipeline with the fresh chamber through a first pipeline assembly, and the electrode solution storage tank 4 forms a circulation pipeline with the cathode chamber and the anode chamber through a second pipeline.

[0043] In the initial state, a lithium-containing solution is added to the fresh chamber storage tank 1 and the alkali solution storage tank 3, pure water is added to the acid solution storage tank 2, and electrode solution is added to the electrode solution storage tank 4.

[0044] When the three-compartment bipolar membrane electrodialysis device is operating, the alkali solution storage tank 4 forms a circulation pipeline with the alkali chamber through a third pipeline assembly, and the acid solution storage tank 2 forms a circulation pipeline with the acid chamber through a fourth pipeline assembly. After operating for a period of time, the alkali solution storage tank 4 forms a circulation pipeline with the acid chamber through the third pipeline assembly, and the acid solution storage tank 2 forms a circulation pipeline with the alkali chamber through the fourth pipeline assembly.

[0045] The first pipeline assembly, the second pipeline assembly, the third pipeline assembly, and the fourth pipeline assembly all include pipelines and circulation pumps arranged on the pipelines. In this embodiment, the circulation pump can be a magnetic pump.

[0046] Example 4:

[0047] In this embodiment, the application of coupling the SNPLOM composite membrane lithium-ion sieve adsorbent with electrodialysis for lithium extraction from simulated lithium-containing solutions was carried out.

[0048] Taking electrodialysis as a carrier, the lithium-ion sieve adsorbent is coupled into the membrane stack and integrated into a system. The high flux of electrodialysis can be used to improve the adsorption and desorption rates of the ion sieve. The electrodialysis bipolar membrane system can provide the best adsorption and desorption environment for the ion sieve adsorbent at low cost and in an environmentally friendly manner, thereby improving the adsorption performance of the ion sieve adsorbent, reducing costs, and reducing operations. The method of coupling the ion sieve adsorbent with bipolar membrane electrodialysis is as follows:

[0049] ① First, assemble the membrane stack of electrodialysis as shown in Figure 1 . This membrane stack uses cation exchange membranes, anion exchange membranes, and bipolar membranes. Among them, the cation exchange membrane only allows cations to pass through, the anion exchange membrane only allows anions to pass through, and the bipolar membrane can generate hydrogen ions and hydroxide ions on both sides of the membrane under the action of an electric field. After energized operation, the acid solution in the acid chamber changes from pure water at the beginning to an acid solution containing HCl and H2SO4, which can provide the best desorption environment required by the ion sieve; the solution in the alkali chamber changes from the initial lithium-containing solution to a highly concentrated, alkaline lithium-containing solution, which can provide the best adsorption environment required by the ion sieve.

[0050] ② Lay the ion sieve adsorbent flat between the membranes and the spacers, that is, embed the ion sieve adsorbent into the acid chamber and the alkali chamber respectively.

[0051] ③Connect the pipeline of the membrane stack embedded with the ion sieve adsorbent to the storage tank. At the same time, introduce an operation of "swapping": that is, swap the pipeline connections of the acid storage tank and the alkali storage tank, so that the acid solution can pass through the alkali chamber and the alkali solution can pass through the acid chamber.

[0052] Under the initial state, Figure 1 Add lithium-containing solution to the middle and dilute chamber storage tank and the alkali solution storage tank, and add pure water to the acid solution storage tank. After running the electrodialysis equipment, in the energized state, the lithium ion sieve adsorbent in the alkali chamber is in the adsorption state, while the ion sieve in the acid chamber is not adsorbed. After a period of time, the lithium ion sieve in the alkali chamber is saturated with adsorption, and a large amount of acid is generated in the acid chamber. At this time, power off and "swap" the pipelines of the acid solution storage tank and the alkali solution storage tank, that is, "swap" the pipelines of the third pipeline component and the fourth pipeline component. Only the liquid circulation is carried out in the non-energized state. At this time, the ion sieve adsorbent that has been saturated with adsorption in the alkali chamber is desorbed after passing through the acid solution, and the ion sieve adsorbent that is not adsorbed in the acid chamber is adsorbed after passing through the alkali solution. At this time, the acid solution storage tank contains a high-purity and high-concentration lithium-containing solution, that is, lithium hydroxide solution, which can be used for subsequent lithium extraction. Then repeat the above operations for cycling.

[0053] The detailed operating conditions and treatment results are as follows:

[0054] Figure 1 As shown, add 2L of simulated lithium-containing solution (Li content 65ppm) to the middle and dilute chamber storage tank and the alkali solution storage tank, add deionized water to the acid chamber, and add 4 %wt Na2SO4 to the electrode chamber. Run the electrodialysis under the condition of a constant voltage of 10 V and stop energizing when the pH reaches about 1. Take liquid samples from the acid chamber and the alkali chamber at regular intervals to measure the lithium concentration and pH.

[0055] Figure 3 shows the change of lithium ion concentration in the acid chamber, and Figure 4 shows the change of lithium ion concentration in the alkali chamber and the middle and dilute chamber; as Figure 3 、 Figure 4 shown, after the SNPLOM composite membrane-like lithium ion sieve adsorbent and electrodialysis are coupled and operated according to this example, the lithium ion concentration in the acid chamber reaches 130ppm after 1h of energization. The lithium ion concentration in the middle and dilute chamber gradually drops to nearly 0ppm due to the transfer to the alkali chamber. The lithium ion concentration in the alkali chamber increases due to the transfer of lithium ions, and at the same time, as the pH rises, the adsorption rate of the lithium ion sieve adsorbent increases, and lithium ions are adsorbed, so the lithium ion concentration first rises and then falls. Therefore, lithium in both chambers is adsorbed by the ion sieve. A lithium desorption rate of 75% and a lithium adsorption rate of 96.6% are achieved. The comprehensive lithium extraction rate is 75%, and the energy consumption is 117kJ / mol (calculated based on the energy consumption per mole of lithium carbonate), which is lower than the traditional lithium extraction method. It can be seen that the coupled lithium extraction of SNPLOM composite membrane-like lithium ion sieve and electrodialysis has high lithium extraction efficiency and low energy consumption. A cycle can be completed in 4 hours, and at the same time, only one-fourth of the time is energized, with low energy consumption, and has good application and development prospects.

[0056] For those not covered above, the prior art shall apply.

[0057] Although some specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and not for limiting the scope of the present invention. Those skilled in the technical field to which the present invention pertains may make various modifications or supplements to the specific embodiments described or use similar means for substitution, but will not deviate from the direction of the present invention or exceed the scope defined by the appended claims. Those skilled in the art should understand that any modification, equivalent substitution, improvement, etc. made to the above embodiments based on the technical essence of the present invention shall be included within the protection scope of the present invention.

Claims

1. A device for extracting lithium by coupling an ion sieve adsorbent with bipolar membrane electrodialysis, characterized in that: It comprises a three-compartment bipolar membrane electrodialysis device and a liquid storage device; the three-compartment bipolar membrane electrodialysis device comprises a cathode chamber, an anode chamber, and at least one membrane unit, the membrane unit is arranged between the cathode chamber and the anode chamber, and the membrane unit comprises an alkali chamber, a dilute chamber, and an acid chamber arranged in sequence in a direction from the cathode chamber to the anode chamber; the alkali chamber and the acid chamber are both provided with a lithium ion sieve adsorbent, the lithium ion sieve adsorbent adsorbs lithium under alkaline conditions and desorbs lithium under acidic conditions; The liquid storage device comprises a dilute chamber storage tank, an alkaline solution storage tank, an acid solution storage tank and a cathode solution storage tank; the dilute chamber storage tank forms a circulation pipeline with the dilute chamber through a first pipeline assembly, and the cathode solution storage tank forms a circulation pipeline with the cathode chamber and the anode chamber through a second pipeline; In the initial state, lithium-containing solution is added to the dilute liquid storage tank and the alkali liquid storage tank, pure water is added to the acid liquid storage tank, and polar liquid is added to the polar liquid storage tank; The alkali solution storage tank forms a circulation pipeline with the alkali chamber or the acid chamber through a third pipeline assembly, and the acid solution storage tank forms a circulation pipeline with the acid chamber or the alkali chamber through a fourth pipeline assembly.

2. The device for extracting lithium by coupling an ion sieve adsorbent with bipolar membrane electrodialysis as claimed in claim 1, characterized in that: The lithium ion sieve adsorbent is prepared by the following method: coating a slurry containing ion sieve powder on a support net, and then coating the support net surface by gel cross-linking to form a coating layer.

3. The device for extracting lithium by coupling an ion sieve adsorbent with bipolar membrane electrodialysis as claimed in claim 2, characterized in that: The coating layer is one of a sodium alginate gel coating layer, a chitosan gel coating layer and a polyvinyl alcohol gel coating layer.

4. The device for extracting lithium by coupling an ion sieve adsorbent with bipolar membrane electrodialysis as claimed in claim 2, characterized in that: The supporting net is a nylon mesh, a polyester mesh or a metal mesh material.

5. The device for extracting lithium by coupling an ion sieve adsorbent with bipolar membrane electrodialysis as claimed in claim 2, characterized in that: The ion sieve powder is manganese-based ion sieve powder, titanium-based ion sieve powder or composite metal-based ion sieve powder.

6. The device for extracting lithium by coupling an ion sieve adsorbent with bipolar membrane electrodialysis as claimed in claim 1, characterized in that: The first pipeline assembly, the second pipeline assembly, the third pipeline assembly and the fourth pipeline assembly all include pipelines and circulation pumps arranged on the pipelines.

7. The device for extracting lithium by coupling an ion sieve adsorbent with bipolar membrane electrodialysis as claimed in claim 1, characterized in that: It comprises a plurality of membrane units, and the plurality of membrane units are connected in series or in parallel.

8. A method for extracting lithium by coupling an ion sieve adsorbent with bipolar membrane electrodialysis, characterized in that: Use the device according to any one of claims 1 to 7; The specific method is as follows: In the initial state, lithium-containing solution is added to the dilute chamber storage tank and the alkali solution storage tank, pure water is added to the acid solution storage tank, and the polar solution storage tank is added to the polar solution; the alkali solution storage tank forms a circulation pipeline with the alkali chamber through the third pipeline assembly, and the acid solution storage tank forms a circulation pipeline with the acid chamber through the fourth pipeline assembly; The bipolar membrane electrodialysis device is started, the alkali chamber adsorbs lithium ions, and the acid chamber generates an acidic environment; when the alkali chamber is saturated with adsorption and the pH of the acid chamber drops to a preset threshold, the bipolar membrane electrodialysis device is turned off, and the pipeline is switched. The alkali solution storage tank forms a circulation pipeline with the acid chamber through a third pipeline assembly, and the acid solution storage tank forms a circulation pipeline with the alkali chamber through a fourth pipeline assembly, so that the acid solution flows through the alkali chamber to desorb lithium ions, and the alkali solution flows through the acid chamber for adsorption; the above steps are repeated to continuously collect a high-concentration lithium-containing solution from the acid solution storage tank.

9. The method for extracting lithium by coupling an ion sieve adsorbent with bipolar membrane electrodialysis as claimed in claim 8, characterized in that: The lithium-containing solution is obtained by filtering, removing impurities or concentrating at least one of a salt lake lithium-containing solution, seawater, oilfield water, geothermal water and industrial wastewater.

10. The method for extracting lithium by coupling an ion sieve adsorbent with bipolar membrane electrodialysis as claimed in claim 8, characterized in that: The preset threshold value of the acid chamber pH is 1-2.

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