A seawater lithium extraction system and method based on solar-powered nanofluids

Abstract

This invention discloses a seawater lithium extraction system and method based on solar-powered nanofluids. The seawater lithium extraction system comprises: a seawater preheating component with a transparent top and an embedded nanofluid; an ion concentration component, each concentration unit including an upper seawater chamber and a lower condensation chamber, the top of the seawater chamber being made of a transparent material, the seawater chamber and the condensation chamber being separated by a hydrophobic membrane for membrane distillation, and the seawater chamber inlet connected to the outlet of the seawater preheating component; a lithium extraction component, each lithium extraction unit including an upper concentrated brine chamber and a lower lithium chloride chamber, the concentrated brine chamber being made of a transparent material, the concentrated brine chamber inlet connected to the seawater chamber outlet, the concentrated brine chamber and the lithium chloride chamber being separated by a lithium-ion transport layer, and the lithium chloride chamber inlet connected to the condensation chamber outlet; and a lithium carbonate recovery component, the lithium carbonate recovery component inlet connected to the lithium chloride chamber outlet. This invention utilizes solar energy as the sole driving energy source and recovers electrical energy using salinity gradients, achieving low-cost and sustainable lithium extraction.

Description

Technical Field

[0001] This invention relates to a seawater lithium extraction system, and more particularly to a seawater lithium extraction system and method based on solar-powered nanofluids, belonging to the field of lithium extraction technology. Background Technology

[0002] With the rapid development of lithium-ion batteries, the global demand for lithium carbonate is increasing rapidly. In 2015, the world's demand for lithium carbonate was 265,000 tons, and by 2025, the global demand is projected to reach 498,000 tons. Lithium ions are gradually becoming a scarce resource that the world is vying for. Current lithium extraction technologies mainly include adsorption, reverse osmosis, and extraction. Adsorption consumes adsorbents and has low adsorption efficiency. Reverse osmosis requires high-grade electrical energy to separate lithium ions. Extraction is complex and requires significant manual labor.

[0003] CN 201811133636.8 proposes a method for lithium extraction from old brine in salt fields. This method uses five steps: (1) magnesium removal by adsorption; (2) lithium removal by segmented variable-speed elution; (3) magnesium removal by adsorption depth using ion exchange resin; (4) reverse osmosis; and (5) lithium carbonate preparation. This method has the following disadvantages: 1. The entire method is cumbersome, requiring a significant amount of time. 2. Each individual step requires a separate device, resulting in substantial costs. 3. The entire process consumes high-grade energy sources such as electricity.

[0004] CN 201611122687.1 proposed a method for lithium extraction from salt lake brine. This method involves passing magnesium-saturated or near-saturated raw brine through a microfiltration device to remove suspended particles, followed by electrodialysis multiple times to obtain the product solution. This method has the following drawbacks: 1. The steps are cumbersome, requiring a significant amount of time for the entire process. 2. Each individual step requires the preparation of a separate device, resulting in substantial costs. 3. The electrodialysis process consumes high-grade energy sources such as electricity, making it unprofitable.

[0005] Traditional lithium extraction equipment is bulky, requires high initial investment, and consumes a lot of energy. How to extract lithium at low cost is a hot topic in current lithium extraction development. In recent years, with social development and population growth, freshwater resources have become increasingly scarce, making seawater desalination a research hotspot for many scholars. Current seawater desalination methods mainly include thermal desalination and reverse osmosis desalination. Seawater is rich in lithium resources. Solar energy is an inexhaustible and renewable energy source that does not pollute the environment, making it both economical and environmentally friendly. Research has found that nanomaterials such as graphene and silver nanoparticles can serve as heat transfer nanofluids in solar-powered seawater desalination technology. The basic principle is that silver nanoparticles absorb sunlight, creating localized high temperatures, and the graphene nanofluid absorbs sunlight, resulting in a dual heating effect that produces water vapor, achieving faster evaporation instead of heating the entire water body as required for boiling. Currently, further reducing the cost of seawater lithium extraction remains a key technological challenge in the development of seawater lithium extraction technology. Summary of the Invention

[0006] The purpose of this invention is to provide a seawater lithium extraction system and method based on solar-powered nanofluids. The system utilizes solar energy as the sole driving force for seawater lithium extraction, and the entire device uses salinity gradient for power recovery, resulting in high efficiency, low cost, and sustainable lithium extraction.

[0007] In a first aspect, the present invention provides a seawater lithium extraction system, comprising:

[0008] The seawater preheating component has a transparent top and incorporates nanofluids to absorb solar energy and heat the seawater.

[0009] An ion concentration assembly includes at least one concentration unit, each concentration unit including an upper seawater chamber and a lower condensation chamber, the top of the seawater chamber being made of a transparent material, the seawater chamber and the condensation chamber being separated by a hydrophobic membrane for membrane distillation to allow water vapor in the seawater chamber to enter the condensation chamber, and the inlet of the seawater chamber being connected to the outlet of the seawater preheating assembly.

[0010] A lithium extraction assembly includes at least one lithium extraction unit, each lithium extraction unit including an upper brine chamber and a lower lithium chloride chamber. The top of the brine chamber is made of a transparent material. The inlet of the brine chamber is connected to the outlet of the seawater chamber. The outlet of the brine chamber is connected to the inlet of the seawater preheating assembly. The brine chamber and the lithium chloride chamber are separated by a lithium ion transport layer to selectively transport lithium ions in the brine chamber to the lithium chloride chamber. The inlet of the lithium chloride chamber is connected to the outlet of the condensation chamber.

[0011] A lithium carbonate recovery assembly, wherein the inlet of the lithium carbonate recovery assembly is connected to the outlet of the lithium chloride chamber to convert lithium chloride into lithium carbonate and recover it.

[0012] In the above-mentioned seawater lithium extraction system, the lithium extraction component further includes an energy storage device, and an electrode is provided in the lithium chloride chamber. The electrode, the energy storage device, and the concentrated brine chamber form a circuit.

[0013] Furthermore, the energy storage device is a battery or a capacitor, used to store the charge or electrical energy generated by lithium-ion transmission;

[0014] The electrode is a graphite electrode or a platinum electrode;

[0015] A delivery pump is provided between the seawater preheating component and the seawater cavity, and the delivery pump is powered by the energy storage device.

[0016] The overall height of the lithium chloride chamber is lower than that of the condensation chamber, so that the fresh water in the condensation chamber enters the lithium chloride chamber under the action of gravity.

[0017] In the aforementioned seawater lithium extraction system, the condensation chamber is equipped with fins, ribs, or rib plates for cooling.

[0018] In the aforementioned seawater lithium extraction system, the lithium carbonate recovery component includes a sedimentation tank.

[0019] In the above-mentioned seawater lithium extraction system, the nanofluid is composed of a first component and a second component;

[0020] The first component is at least one of activated carbon particles, graphene, graphene oxide, reduced graphene oxide, and carbon nanotubes;

[0021] The second component is at least one of silver nanoparticles and gold nanoparticles;

[0022] The mass ratio of the first component to the second component is (100-10):1.

[0023] In the above-mentioned seawater lithium extraction system, the hydrophobic membrane used for membrane distillation is a polytetrafluoroethylene (PTFE) hydrophobic membrane, a polyvinylidene fluoride (PVDF) hydrophobic membrane, or a polypropylene (PP) hydrophobic membrane.

[0024] The lithium-ion transport layer is made of lithium-ion liquid film or lithium-ion exchange resin.

[0025] In the above-mentioned seawater lithium extraction system, the seawater lithium extraction system is either 1) or 2) as follows:

[0026] 1) The ion concentration assembly includes two or more concentration units, and the lithium extraction assembly includes two or more lithium extraction units. Each concentration unit and each lithium extraction unit constitute a concentration and lithium extraction unit, and the concentration and lithium extraction units are arranged in parallel.

[0027] 2) The lithium extraction assembly includes two or more lithium extraction units, and each lithium extraction unit is connected in series.

[0028] In a second aspect, the present invention provides a method for lithium extraction from seawater, utilizing the seawater lithium extraction system described in any of the above claims, comprising the following steps:

[0029] S1. The lithium chloride chamber is filled with lithium chloride solution;

[0030] S2. Seawater and nanofluid heated by the seawater preheating component enter the seawater chamber and continuously absorb solar energy in the seawater chamber, causing the temperature to rise continuously. The seawater evaporates through membrane distillation, and the water vapor passes through the hydrophobic membrane used for membrane distillation and enters the condensation chamber. The condensed fresh water flows into the lithium chloride chamber. The concentrated brine and nanofluid in the seawater chamber enter the concentrated brine chamber and continuously absorb solar energy in the concentrated brine chamber.

[0031] S3. Lithium ions in the concentrated saline chamber move into the lithium chloride chamber under the influence of temperature and concentration differences.

[0032] S4. The lithium chloride in the lithium chloride chamber enters the lithium carbonate recovery component and reacts with carbon dioxide or sodium carbonate to form lithium carbonate precipitate.

[0033] In the above-mentioned seawater lithium extraction method, in step S1, the concentration of the lithium chloride solution is 0.01 ppm to 0.5 ppm;

[0034] In step S3, fresh water is added to the lithium chloride chamber through the condensation chamber to maintain the concentration difference on both sides of the lithium ion transport layer.

[0035] The present invention has the following beneficial effects:

[0036] (1) This invention uses only solar energy as the sole energy source to extract lithium ions from seawater with low lithium concentration.

[0037] (2) The present invention utilizes the linkage of nanofluid and membrane distillation technology to maintain the concentration difference, ensuring that the device can operate continuously.

[0038] (3) The entire device utilizes the salt gradient for energy recovery, which is highly efficient, low-cost, and allows for sustainable lithium extraction.

[0039] (4) The raw materials of this invention are all seawater, and the products are lithium carbonate and high-quality electrical energy, thus achieving the effect of turning waste into treasure.

[0040] (5) The present invention has a simple structure and can achieve low-cost industrial lithium extraction through parallel connection. Attached Figure Description

[0041] Figure 1A schematic diagram of the overall structure of a seawater lithium extraction system based on solar-powered nanofluids provided in an embodiment of the present invention;

[0042] Figure 2 The schematic diagram of the overall structure of the seawater lithium extraction system based on solar nanofluids provided in another embodiment of the present invention shows a lithium extraction module formed by three modules connected in parallel, which is convenient for industrial application.

[0043] Figure 3 This is a schematic diagram of the overall structure of a seawater lithium extraction system based on solar nanofluids, provided in another embodiment of the present invention. It consists of two lithium extraction modules connected in series, which can effectively purify the final lithium chloride solution.

[0044] Labels for each item in the figure:

[0045] 100 - Seawater preheating component; 101 - Activated carbon particles; 102 - Silver nanoparticles; 103 - Seawater inlet pipe; 104 - Nanofluid pipe;

[0046] 200 - Ion concentration unit; 201 - Seawater chamber; 202 - Condensation chamber; 203 - Hydrophobic membrane for membrane distillation; 204 - Cooling fins; 205 - Transfer pump; 206 - Freshwater pipeline;

[0047] 300 - Lithium extraction component; 301 - Concentrated brine chamber; 302 - Lithium chloride chamber; 303 - Lithium ion transport layer; 304 - Lithium chloride pipeline; 305 - Energy storage device; 306 - Electrode;

[0048] 400-Lithium carbonate recovery unit. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0050] In the description of this invention, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the system or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the use of terms such as "first," "second," etc., to define components is merely for the convenience of distinguishing the aforementioned components; unless otherwise stated, these terms have no special meaning and should not be construed as indicating or implying relative importance.

[0051] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "assembly," "setup," and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0052] The seawater lithium extraction system provided in the embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0053] like Figure 1As shown, an embodiment of the present invention provides a seawater lithium extraction system including a seawater preheating component 100, an ion concentration component 200, a lithium extraction component 300, and a lithium carbonate recovery component 400. The seawater preheating component 100 primarily functions to preheat seawater. Its top is made of a transparent material, such as transparent glass, and contains a nanofluid to absorb solar energy and heat the seawater. The nanofluid consists of activated carbon particles 101 and silver nanoparticles 102, for example, in a mass ratio of 100:1 to 10:1. The specific ratio can be determined based on performance requirements and cost. It is understood that the silver nanoparticles 102 can be replaced by gold nanoparticles, and the activated carbon particles 101 can be replaced by carbon nanomaterials such as graphene, graphene oxide, reduced graphene oxide, and carbon nanotubes. The seawater preheating component 100 is externally connected to a seawater inlet pipe 103 and a nanofluid pipe 104. Seawater enters the seawater preheating component 100 through the seawater inlet pipe 103, and the nanofluid absorbs sunlight to heat the seawater. The nanofluid mixed with seawater flows out through the nanofluid pipe 104. The ion concentration component 200 includes an upper seawater chamber 201 and a lower condensation chamber 202. The top of the seawater chamber 201 is made of a transparent material, such as transparent glass. The seawater chamber 201 and the condensation chamber 202 are separated by a hydrophobic membrane 203 for membrane distillation, allowing water vapor in the seawater chamber 201 to enter the condensation chamber 202. For example, the hydrophobic membrane 203 for membrane distillation is a polytetrafluoroethylene (PTFE) hydrophobic membrane, a polyvinylidene fluoride (PVDF) hydrophobic membrane, or a polypropylene (PP) hydrophobic membrane. The inlet of the seawater chamber 201 is connected to the outlet of the seawater preheating component 100, specifically through the nanofluid pipe 104. A delivery pump 205 is provided between the seawater preheating component 100 and the seawater chamber 201 to drive the flow of nanofluid. The delivery pump 205 can be a peristaltic pump, a small pump, or a low-energy pump. Under the action of the delivery pump 205, the nanofluid containing preheated seawater from the seawater preheating component 100 enters the seawater chamber 201. The condensation chamber 202 is provided with fins, ribs, or plates for cooling, such as cooling fins 204. The lithium extraction component 300 includes an upper concentrated brine chamber 301, a lower lithium chloride chamber 302, and an energy storage device 305. The top of the concentrated brine chamber 301 is made of a transparent material, such as transparent glass. The inlet of the concentrated brine chamber 301 is connected to the outlet of the seawater chamber 201, specifically through a nanofluid pipe 104. The outlet of the concentrated brine chamber 301 is connected to the inlet of the seawater preheating component 100, specifically through a nanofluid pipe 104.A lithium-ion transport layer 303 separates the concentrated brine chamber 301 and the lithium chloride chamber 302. The lithium-ion transport layer 303 is made of a lithium-ion liquid membrane or lithium-ion exchange resin to selectively transport lithium ions from the concentrated brine chamber 301 to the lithium chloride chamber 302. The inlet of the lithium chloride chamber 302 is connected to the outlet of the condensation chamber 202, specifically via a freshwater pipe 206. After concentration by the ion concentration component 200, the lithium extracted by the nanofluid is returned to the seawater preheating component 100. An electrode 306, which is either a graphite electrode or a platinum electrode, is installed inside the lithium chloride chamber 302. The electrode 306 forms a circuit with the energy storage device 305 and the concentrated brine chamber 301. The energy storage device 305 is a battery or capacitor to store the charge or electrical energy generated by lithium-ion transport. During the lithium extraction process, the above circuit converts salinity gradient energy into electrical energy, which is then recovered and stored in the energy storage device 305. The transfer pump 205 is powered by the energy storage device 305. The overall height of the lithium chloride chamber 302 is lower than that of the condensation chamber 202, so that fresh water in the condensation chamber 302 enters the lithium chloride chamber 302 under gravity, specifically through the fresh water pipe 206. The lithium carbonate recovery assembly 400 has its inlet connected to the outlet of the lithium chloride chamber 302, specifically through the lithium chloride pipe 304, to convert lithium chloride into lithium carbonate for recovery. The lithium carbonate recovery assembly 400 includes a sedimentation tank to collect lithium carbonate precipitate. The components can be fixed using clamps, flanges, or other methods.

[0054] Specific implementation method: Before operation, the lithium chloride chamber 302 is filled with low-concentration lithium chloride, such as 0.01ppm to 0.5ppm, specifically 0.2ppm, to start the device. At the start of operation, seawater is introduced into the seawater preheating component 100 through the seawater inlet pipe 103. The nanofluid in this component absorbs sunlight, and the silver nanoparticles 102 generate local high temperatures through the plasmon resonance effect. Under the heat absorption and conductivity of the activated carbon particles, the seawater is heated. Subsequently, the nanofluid mixed with seawater is pumped into the seawater chamber 201 through the transfer pump 205. The seawater chamber 201 continuously absorbs solar energy, and the temperature continues to rise. The seawater evaporates through membrane distillation, and the water vapor passes through the hydrophobic membrane 203 of the membrane distillation process and enters the condensation chamber 202. It condenses into fresh water on the cooling fins 204 and then flows into the lithium chloride chamber 302 to dilute the lithium chloride concentration. The nanofluid in the seawater chamber 201 flows into the concentrated brine chamber 301 through the nanofluid pipe 104, continuing to absorb heat. As the temperature continues to rise, lithium ions in the concentrated brine chamber 301 move towards the lithium chloride chamber 302 driven by the temperature and concentration difference. However, due to the selective effect of the lithium ion transport layer 303, only lithium ions can pass through. As the lithium ions move in a directional manner, the generated electrical energy is collected by the energy storage device 305 and used to power the pump 205. Because lithium extraction increases the concentration of the lithium chloride solution, the concentration difference across the lithium ion transport layer 303 decreases. This is replenished by fresh water in the condensation chamber 202. Furthermore, the lithium ions diffuse through the lithium chloride pipe 304 into the lithium carbonate recovery component 400, maintaining the concentration difference across the lithium ion transport layer 303 and continuously generating the driving force for lithium extraction. Lithium ions diffuse into the lithium carbonate recovery component 400, where the addition of carbon dioxide or sodium carbonate precipitates lithium carbonate.

[0055] Throughout the process, the lithium adsorption rate can be adjusted by changing the temperature of the nanofluid (adjusting the illumination time) or by altering the concentration across the lithium-ion liquid film. The flow rates of seawater and the flow electrode can be controlled by a pump. Additionally, fresh water can be added to the lithium chloride chamber through the condensation chamber to maintain the concentration difference across the lithium-ion transport layer.

[0056] Another embodiment of the present invention provides a seawater lithium extraction system, wherein the ion concentration component 200 includes two or more concentration units, and the lithium extraction component 300 includes two or more lithium extraction units, each concentration unit and the lithium extraction unit constituting a concentration-lithium extraction unit, and the concentration-lithium extraction units are arranged in parallel. Figure 2As shown, the ion concentration assembly 200 includes a first concentration unit, a second concentration unit, and a third concentration unit, and the lithium extraction assembly 300 includes a first lithium extraction unit, a second lithium extraction unit, and a third lithium extraction unit. The first concentration unit and the first lithium extraction unit constitute the first concentration and lithium extraction unit; the second concentration unit and the second lithium extraction unit constitute the second concentration and lithium extraction unit; and the third concentration unit and the third lithium extraction unit constitute the third concentration unit. The first, second, and third lithium extraction units are connected in parallel, meaning they share a single nanofluid main pipeline. The main pipeline diverts flow into multiple concentration units, and after concentration, the fluid enters the corresponding lithium extraction unit. The three concentration and lithium extraction units share a single lithium chloride main pipeline, and all lithium chloride pipelines from the units converge into the main pipeline. The remaining connections are the same as described above. Figure 1 This embodiment utilizes two or more lithium concentration and extraction units connected in parallel to further realize industrial-scale seawater desalination for lithium extraction and power generation.

[0057] Another embodiment of the present invention provides a seawater lithium extraction system, wherein the lithium extraction component 300 includes two or more lithium extraction units, and the lithium extraction units are arranged in series. For example... Figure 3 As shown, the lithium extraction assembly 300 includes a first lithium extraction unit and a second lithium extraction unit, which are connected in series. Specifically, the outlet of the concentrated brine chamber of the first lithium extraction unit is connected to the inlet of the concentrated brine chamber of the second lithium extraction unit, and the outlet of the lithium chloride chamber of the first lithium extraction unit is connected to the inlet of the lithium chloride chamber of the second lithium extraction unit. The remaining connections are the same. Figure 1 This embodiment utilizes two or more lithium extraction units connected in series to further improve the purity of lithium products obtained from industrial-scale seawater desalination.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A seawater lithium extraction system, characterized in that, include: The seawater preheating component has a transparent top and incorporates nanofluids to absorb solar energy and heat the seawater. An ion concentration assembly includes at least one concentration unit, each concentration unit including an upper seawater chamber and a lower condensation chamber, the top of the seawater chamber being made of a transparent material, the seawater chamber and the condensation chamber being separated by a hydrophobic membrane for membrane distillation to allow water vapor in the seawater chamber to enter the condensation chamber, and the inlet of the seawater chamber being connected to the outlet of the seawater preheating assembly. A lithium extraction assembly includes at least one lithium extraction unit, each lithium extraction unit including an upper brine chamber and a lower lithium chloride chamber. The top of the brine chamber is made of a transparent material. The inlet of the brine chamber is connected to the outlet of the seawater chamber. The outlet of the brine chamber is connected to the inlet of the seawater preheating assembly. The brine chamber and the lithium chloride chamber are separated by a lithium ion transport layer to selectively transport lithium ions in the brine chamber to the lithium chloride chamber. The inlet of the lithium chloride chamber is connected to the outlet of the condensation chamber. A lithium carbonate recovery assembly, wherein the inlet of the lithium carbonate recovery assembly is connected to the outlet of the lithium chloride chamber to convert lithium chloride into lithium carbonate and recover it.

2. The seawater lithium extraction system according to claim 1, characterized in that: The lithium extraction assembly also includes an energy storage device. The lithium chloride chamber is equipped with an electrode, which forms a circuit with the energy storage device and the concentrated brine chamber.

3. The seawater lithium extraction system according to claim 2, characterized in that: The energy storage device is a battery or capacitor, used to store the charge or electrical energy generated by lithium-ion transmission. The electrode is a graphite electrode or a platinum electrode; A delivery pump is provided between the seawater preheating component and the seawater cavity, and the delivery pump is powered by the energy storage device. The overall height of the lithium chloride chamber is lower than that of the condensation chamber, so that fresh water in the condensation chamber enters the lithium chloride chamber under the action of gravity.

4. The seawater lithium extraction system according to any one of claims 1-3, characterized in that: The condensation chamber is provided with fins, ribs or rib plates for cooling.

5. The seawater lithium extraction system according to any one of claims 1-4, characterized in that: The lithium carbonate recovery assembly includes a sedimentation tank.

6. The seawater lithium extraction system according to any one of claims 1-5, characterized in that: The nanofluid is composed of a first component and a second component; The first component is at least one of activated carbon particles, graphene, graphene oxide, reduced graphene oxide, and carbon nanotubes; The second component is at least one of silver nanoparticles and gold nanoparticles; The mass ratio of the first component to the second component is (100~10):

1.

7. The seawater lithium extraction system according to any one of claims 1-6, characterized in that: The hydrophobic membrane used for membrane distillation is a polytetrafluoroethylene hydrophobic membrane, a polyvinylidene fluoride hydrophobic membrane, or a polypropylene hydrophobic membrane. The lithium-ion transport layer is made of lithium-ion liquid film or lithium-ion exchange resin.

8. The seawater lithium extraction system according to any one of claims 1-7, characterized in that: The seawater lithium extraction system is either 1) or 2) below. 1) The ion concentration assembly includes two or more concentration units, and the lithium extraction assembly includes two or more lithium extraction units. Each concentration unit and each lithium extraction unit constitute a concentration and lithium extraction unit, and the concentration and lithium extraction units are arranged in parallel. 2) The lithium extraction assembly includes two or more lithium extraction units, and each lithium extraction unit is connected in series.

9. A method for extracting lithium from seawater, characterized in that, The seawater lithium extraction system according to any one of claims 1-8 comprises the following steps: S1. The lithium chloride chamber is filled with lithium chloride solution; S2. Seawater and nanofluid heated by the seawater preheating component enter the seawater chamber and continuously absorb solar energy in the seawater chamber, causing the temperature to rise continuously. The seawater evaporates through membrane distillation, and the water vapor passes through the hydrophobic membrane used for membrane distillation and enters the condensation chamber. The condensed fresh water flows into the lithium chloride chamber. The concentrated brine and nanofluid in the seawater chamber enter the concentrated brine chamber and continuously absorb solar energy in the concentrated brine chamber. S3. Lithium ions in the concentrated saline chamber move into the lithium chloride chamber under the influence of temperature and concentration differences. S4. The lithium chloride in the lithium chloride chamber enters the lithium carbonate recovery component and reacts with carbon dioxide or sodium carbonate to form lithium carbonate precipitate.

10. The method for extracting lithium from seawater according to claim 9, characterized in that: In step S1, the concentration of the lithium chloride solution is 0.01 ppm to 0.5 ppm; In step S3, fresh water is added to the lithium chloride chamber through the condensation chamber to maintain the concentration difference on both sides of the lithium ion transport layer.

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