Method for lithium extraction from salt lake by electrodialysis based on shallow geothermal regulation and membrane decontamination

Abstract

The application discloses a kind of based on shallow ground source heat regulation and control's electrodialysis salt lake lithium extraction and membrane pollution removal method, including ultra-shallow ground source heat pipe, surface ground source heat pipe, brine tank, fresh water tank, porous medium membrane and external circuit, wherein: using the heat of ultra-shallow ground source, surface ground source, respectively, fresh water tank and brine tank are heated or cooled, so that there is certain temperature difference between fresh water, brine, voltage is applied on the two sides of system, using electrodialysis process principle, lithium ion, magnesium ion in brine can be separated from original solution;Use specific cation selective exchange membrane, lithium ion is separated from lithium, magnesium mixed solution;Meanwhile, magnesium ion will adhere to cation selective exchange membrane and its ion channel, and form membrane blockage;At this time, remove electric field, based on Soret effect, magnesium ion will spontaneously migrate from high temperature side to low temperature side, and form no energy consumption membrane pollution removal.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of geothermal heat source utilization and electrodialysis lithium extraction, and particularly relates to an electrodialysis salt lake lithium extraction and membrane pollution removal method based on shallow geothermal regulation. BACKGROUND

[0002] In recent years, new energy mainly based on underground pipe heat exchange is widely used in heating and refrigeration systems of various indoor buildings and industrial fields, and becomes an important part of renewable energy.

[0003] Geothermal energy utilization is based on the characteristics of low specific heat, large mass, and easy long-time storage of a large amount of heat or cold. Based on this part of energy, low-cost and pollution-free heat exchange can be performed on the target system, so as to achieve the effect of refrigeration or heating. In the present application, the soil is divided into temperature-variable layer soil above 4m underground and constant-temperature layer soil below 4m underground. The temperature-variable layer soil refers to the soil whose temperature changes with the change of external conditions such as air temperature, humidity and rainfall, and is greatly affected by the outside. The constant-temperature layer soil refers to the soil that maintains a certain temperature all year round. This part of soil is a certain distance from the ground and is usually not affected by external temperature factors.

[0004] In recent years, with the rapid development of the lithium battery industry, lithium and its compounds have become necessities for China's metallurgical, chemical and other industries. So far, the common methods for extracting lithium include calcination, evaporation, chemical precipitation and nanofiltration. However, most of these technologies still have defects. For example, in the process of calcining lithium-containing ores by calcination method, there are problems of acid mist emission and energy consumption. Evaporation method can only concentrate lithium in brine but cannot separate magnesium. Chemical precipitation method reacts other chemicals with lithium ions to generate high-concentration lithium hydroxide product, but this method consumes a large amount of chemical products, produces byproduct pollutants calcium carbonate precipitation, and has a low generation rate of lithium hydroxide. Nanofiltration method is a separation method based on nanofiltration membrane. Although it has low energy consumption, high efficiency and can separate magnesium ions and lithium ions in salt lake, it is difficult to separate them only by size exclusion mechanism because the ionic radii of magnesium ions and lithium ions are very close (magnesium ion: 0.428 nm, lithium ion: 0.379 nm).

[0005] Electrodialysis technology is a method that uses ion-selective exchange membrane to drive the directional migration of anions and cations in brine under the action of a direct current electric field, so as to achieve the purpose of separation, purification and concentration of electrolyte solution. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a method for extracting lithium from salt lakes by electrodialysis based on shallow geothermal regulation and membrane decontamination, aiming at the deficiencies in the prior art, to solve the technical problem of low purity and heavy pollution of lithium ions extracted from salt lakes, effectively combine geothermal heat and electrodialysis, use geothermal heat to enhance the lithium extraction efficiency of electrodialysis, and use the Soret effect to achieve energy-free membrane decontamination.

[0007] The present application adopts the following technical solutions:

[0008] A method for extracting lithium from salt lakes by electrodialysis based on shallow geothermal regulation, in summer, connecting the surface geothermal heat pipe to the freshwater tank, connecting the super-shallow geothermal heat pipe to the brine tank, storing the desalination original solution containing a large amount of lithium ions and magnesium ions in the brine tank as the desalination chamber of the electrodialysis process; in winter, connecting the super-shallow geothermal heat pipe to the freshwater tank, connecting the surface geothermal heat pipe to the brine tank; storing freshwater in the freshwater tank, collecting desalted lithium ions as the lithium ion recovery chamber of the electrodialysis process.

[0009] When powered on, the ions in the brine tank migrate directionally under the action of the electric field, the cations migrate to the cathode direction of the electric field, and the anions migrate to the anode direction of the electric field; the lithium ions pass through the monovalent cation selective membrane, and the magnesium ions are attached and accumulated on the surface of the monovalent cation selective membrane and the pore openings to form membrane blockage; after the electric field is removed, under the action of geothermal heat, a temperature field with an inverse concentration gradient is formed between the freshwater tank and the brine tank, and the magnesium ions attached and accumulated on the cation selective membrane migrate from the high-temperature side to the low-temperature side.

[0010] Specifically, a porous medium membrane is arranged between the freshwater tank and the brine tank.

[0011] Further, in summer, one end of the first brine tank is connected to the negative electrode of the power supply through the first freshwater tank, the other end is connected to the positive electrode of the power supply through the second freshwater tank, a first cation selective exchange membrane is arranged between the first brine tank and the first freshwater tank, a first anion selective membrane is arranged between the first brine tank and the second freshwater tank, the first freshwater tank and the second freshwater tank are connected to the surface geothermal heat pipe, and the first brine tank is connected to the super-shallow geothermal heat pipe.

[0012] Further, a vacuum heat insulation section is arranged at the connection between the super-shallow geothermal heat pipe and the first brine tank.

[0013] Further, in winter, one end of the second brine tank is connected to the negative electrode of the power supply through the third freshwater tank, the other end is connected to the positive electrode of the power supply through the fourth freshwater tank, a second cation selective exchange membrane is arranged between the second brine tank and the third freshwater tank, a second anion selective membrane is arranged between the second brine tank and the fourth freshwater tank, the second brine tank is connected to the surface geothermal heat pipe, and the third freshwater tank and the fourth freshwater tank are connected to the super-shallow geothermal heat pipe.

[0014] Further, the connection part of the super-shallow ground source heat pipe and the third fresh water tank and the fourth fresh water tank is provided with a vacuum heat insulation section.

[0015] Further, the external circuit connected with the power supply is operated by constant voltage or constant current direct current electric field.

[0016] Further, the vacuum heat insulation section of the super-shallow ground source heat pipe is located on the ground surface layer.

[0017] Specifically, the brine tank is coated or covered with a radiation-proof coating material on the outer layer to reduce the radiation heat absorbed by the brine tank, and the fresh water tank is coated with a coating material easy to absorb radiation on the outer layer to increase the radiation heat absorbed by the fresh water tank.

[0018] Specifically, the brine tank and the fresh water tank are further increased in temperature difference between them under the joint action of the ground source heat and the radiation heat.

[0019] Compared with the prior art, the present application has at least the following beneficial effects:

[0020] The present application is a method for lithium extraction and membrane pollution removal of salt lake by electrodialysis based on shallow ground source heat regulation, which utilizes the heat of super-shallow ground source and ground surface source to heat or cool the fresh water tank and the brine tank respectively, so that a certain temperature difference exists between the fresh water and the brine, and a voltage is applied on both sides of the system, and lithium ions and magnesium ions in the brine can be separated from the original solution by using the principle of electrodialysis process, and a specific monovalent cation selective exchange membrane is used to separate lithium ions from the lithium-magnesium mixed solution, but the magnesium ions will adhere to the monovalent cation selective exchange membrane and its ion channels to form membrane clogging, at this time, the electric field is removed, and based on the Soret effect, the magnesium ions will spontaneously migrate from the high temperature side to the low temperature side to form a non-energy-consuming membrane pollution removal.

[0021] Further, the porous medium membrane is arranged between the fresh water tank and the brine tank to separate cations and anions in the raw material solution.

[0022] Further, in summer, the ground surface temperature is relatively high, the ground surface heat source temperature is used to heat the fresh water in the fresh water tank, the super-shallow ground source temperature is relatively low, the super-shallow ground source is used to cool the brine in the brine tank, and the coating material easy to absorb radiation is coated on the outer surface of the fresh water tank and the radiation-proof coating material is coated on the outer surface of the brine tank to keep a larger temperature gradient between the fresh water tank and the brine tank, which is helpful for ion migration.

[0023] Further, the vacuum heat insulation section is arranged because the ground surface temperature is relatively high in summer, the super-shallow ground source is used to cool the brine tank to prevent the ground surface heat from being transferred to the super-shallow ground source in the process.

[0024] Further, in winter, the temperature of the super-shallow geothermal source is higher, the fresh water in the fresh water tank is heated by the temperature of the super-shallow geothermal source, the temperature of the ground surface is relatively low, the brine in the brine tank is cooled by the ground surface geothermal source, and the outer surface of the fresh water tank is coated with a radiation-absorbing coating material, the outer surface of the brine tank is coated with a radiation-resistant coating material, a greater temperature gradient is maintained between the fresh water tank and the brine tank, and ion migration is facilitated.

[0025] Further, the vacuum insulation section is arranged because the temperature of the super-shallow geothermal source is higher in winter, and the brine tank is cooled by the ground surface geothermal source to prevent the ground surface geothermal source from cooling the super-shallow geothermal heat pipe during the process.

[0026] Further, the electrodialysis process requires an external constant-voltage or constant-current direct-current power supply.

[0027] Further, because the temperature of the super-shallow geothermal source is relatively constant, the vacuum insulation section is arranged to prevent heat exchange between the super-shallow geothermal heat pipe located at the ground surface and the soil at the ground surface during the heating or cooling process.

[0028] Further, the efficiency of lithium extraction by the electrodialysis process and the purity of lithium ions are improved.

[0029] In summary, the combination of lithium extraction by electrodialysis and geothermal heat effectively improves the efficiency of the lithium extraction process and reduces the energy consumption caused by membrane clogging and cleaning.

[0030] The technical solutions of the present application will be further described in detail below with reference to the accompanying drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 a schematic diagram of the arrangement in summer;

[0032] Figure 2 a schematic diagram of the arrangement in winter;

[0033] Figure 3 a schematic diagram of the electrodialysis process;

[0034] Figure 4 a three-dimensional sectional view of each component;

[0035] Figure 5 a schematic diagram of membrane clogging of the present application;

[0036] Figure 6 a columnar schematic diagram of the concentration of magnesium ions at the entrance of the ion channel under the action of different temperature gradients.

[0037] Wherein, 1. first fresh water tank; 2. second fresh water tank; 3. first brine tank; 4. first cation selective exchange membrane; 5. first anion selective membrane; 6. third fresh water tank; 7. fourth fresh water tank; 8. second brine tank; 9. second cation selective exchange membrane; 10. second anion selective membrane; 11. negative electrode plate; 12. positive electrode plate. DETAILED DESCRIPTION

[0038] The technical solutions of the present application will be described clearly and completely below, obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0039] In the present application, all the embodiments and preferred embodiments mentioned in the present application can be combined to form new technical solutions, if not otherwise specified.

[0040] In the present application, all the technical features and preferred features mentioned in the present application can be combined to form new technical solutions, if not otherwise specified.

[0041] In the present application, percentage (%) or part refers to the weight percentage or weight part of the composition, if not otherwise specified.

[0042] In the present application, all the components or preferred components mentioned in the present application can be combined to form new technical solutions, if not otherwise specified.

[0043] In the present application, unless otherwise specified, the numerical range "a~b" represents a shorthand notation for any real number combination between a and b, wherein a and b are both real numbers. For example, the numerical range "6~22" represents that all the real numbers between "6~22" have been listed herein, and "6~22" is only a shorthand notation for these numerical combinations.

[0044] The lower limit and upper limit of the range disclosed in the present application can be one or more lower limits and one or more upper limits, respectively.

[0045] In the present application, the term "and / or" used herein means any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0046] In the present application, unless otherwise specified, each reaction or operation step can be carried out sequentially or according to the sequence. Preferably, the reaction method herein is carried out sequentially.

[0047] Unless otherwise defined, all terms of art used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application pertains. In addition, any method or material similar or equivalent in function to those described herein can be used in the practice of the present application.

[0048] The present application provides a method for extracting lithium from salt lake by electrodialysis based on shallow geothermal regulation and membrane decontamination, which utilizes the heat of ultra-shallow geothermal source and surface geothermal source to heat or cool the fresh water tank and the brine tank, so that there is a certain temperature difference between the fresh water and the brine, and a voltage is applied on both sides of the system. According to the principle of electrodialysis process, lithium ions and magnesium ions in the brine can be separated from the original solution. A specific cation selective exchange membrane is used to separate lithium ions from the mixed solution of lithium and magnesium. At the same time, magnesium ions will adhere to the cation selective exchange membrane and its ion channels, forming membrane blockage. At this time, the electric field is removed, and based on the Soret effect, magnesium ions will spontaneously migrate from the high temperature side to the low temperature side, forming a non-energy-consuming membrane decontamination.

[0049] The present application provides a method for extracting lithium from salt lake by electrodialysis based on shallow geothermal regulation and membrane decontamination, which includes two modes of summer and winter, as follows:

[0050] In summer, the surface geothermal heat pipe is connected to the fresh water tank, and the ultra-shallow geothermal heat pipe is connected to the brine tank. The brine tank stores desalination original solution containing a large amount of lithium ions and magnesium ions, which serves as the desalination chamber of the electrodialysis process. The fresh water tank stores fresh water to collect lithium ions after desalination, which serves as the lithium ion recovery chamber of the electrodialysis process. A porous medium membrane is arranged between the fresh water tank and the brine tank.

[0051] Please refer to Figure 1 , one end of the first brine tank 3 is connected to the negative electrode of the power supply through the first fresh water tank 1, and the other end is connected to the positive electrode of the power supply through the second fresh water tank 2. A first cation selective exchange membrane 4 is arranged between the first brine tank 3 and the first fresh water tank 1, and a first anion selective membrane 5 is arranged between the first brine tank 3 and the second fresh water tank 2. The first fresh water tank 1 and the second fresh water tank 2 are connected to the surface geothermal heat pipe, and the first brine tank 3 is connected to the ultra-shallow geothermal heat pipe. A vacuum insulation section is arranged at the connection between the ultra-shallow geothermal heat pipe and the first brine tank 3.

[0052] Since the surface temperature is high in summer, and the ultra-shallow geothermal source temperature is constant throughout the year, maintaining at 15℃, the surface geothermal source is used to heat the first fresh water tank 1 and the second fresh water tank 2, and the ultra-shallow geothermal source is used to cool the first brine tank 3. At the same time, a radiation-proof coating material is applied or covered on the outer layer of the first brine tank 3 to reduce the absorption of external radiation heat by the first brine tank 3. A coating material that easily absorbs radiation is applied on the outer layer of the first fresh water tank 1 and the second fresh water tank 2 to further increase the temperature difference between the first fresh water tank 1, the second fresh water tank 2 and the first brine tank 3.

[0053] In winter, the ground surface temperature is low, while the temperature of the super-shallow ground source is constant. The super-shallow ground source heat pipe is connected to the fresh water tank, the ground surface ground source heat pipe is connected to the brine tank, the brine tank stores desalination original solution containing a large amount of lithium ions and magnesium ions, and serves as a desalination chamber of the electrodialysis process. The fresh water tank stores fresh water to collect lithium ions after desalination, and serves as a lithium ion recovery chamber of the electrodialysis process. A porous medium film is arranged between the fresh water tank and the brine tank.

[0054] Please refer to Figure 2 One end of the second brine tank 8 is connected to the negative electrode of the power supply through the third fresh water tank 6, and the other end is connected to the positive electrode of the power supply through the fourth fresh water tank 7. A second cation selective exchange film 9 is arranged between the second brine tank 8 and the third fresh water tank 6, and a second anion selective film 10 is arranged between the second brine tank 8 and the fourth fresh water tank 7. The second brine tank 8 is connected to the ground surface ground source heat pipe, and the third fresh water tank 6 and the fourth fresh water tank 7 are connected to the super-shallow ground source heat pipe. A vacuum insulation section is arranged at the connection between the super-shallow ground source heat pipe and the third fresh water tank 6 and the fourth fresh water tank 7.

[0055] Because the ground surface temperature is low in winter, although the temperature of the super-shallow ground source is constant throughout the year, it is slightly higher than the ground surface temperature in winter. Therefore, the third fresh water tank 6 and the fourth fresh water tank 7 are heated by the super-shallow ground source, and the second brine tank 8 is cooled by the ground surface ground source. At the same time, a radiation-proof coating material is applied or covered on the outer layer of the second brine tank 8 to reduce the absorption of external radiation heat by the second brine tank 8. A coating material that easily absorbs radiation is applied or covered on the outer layer of the third fresh water tank 6 and the fourth fresh water tank 7 to increase the absorption of external radiation by the third fresh water tank 6 and the fourth fresh water tank 7, so that the temperature difference between the third fresh water tank 6, the fourth fresh water tank 7 and the second brine tank 8 is further increased.

[0056] The total length of the super-shallow ground source heat pipe is 5.8 m, the underground buried pipe length is 4 m, and the ground length is 1.8 m.

[0057] The total length of the ground surface ground source heat pipe is 2.8 m, the underground buried pipe length is 1 m, and the ground length is 1.8 m.

[0058] The porous medium film is a specific monovalent anion selective film and a monovalent cation selective film.

[0059] Under the action of an electric field, lithium ions are separated and collected from the desalination original solution.

[0060] Please refer to Figure 3 The arrangement order of each electrodialysis unit from the cathode to the anode is:

[0061] Fresh water tank, cation selective exchange membrane, bipolar membrane, brine tank, bipolar membrane, anion selective exchange membrane, fresh water tank; the bipolar membrane is arranged between the cation selective exchange membrane and the anion selective exchange membrane, so that the fresh water tank, the brine tank and the fresh water tank constitute an alkali chamber, a liquid chamber and an acid chamber; the alkali chamber and the acid chamber are the fresh water tank, in which fresh water is filled, and the liquid chamber is the brine tank, in which a lithium-containing original solution is filled.

[0062] When the electrodialysis system is powered on, the ions in the liquid chamber migrate directionally under the action of the electric field, in which the cations migrate towards the cathode of the electric field, and the anions migrate towards the anode of the electric field, since the cation selective exchange membrane and the anion selective exchange membrane are both monovalent ion exchange membranes, only lithium ions in the brine can pass through, and magnesium ions will adhere to the channel opening of the ion exchange membrane, thereby forming membrane clogging.

[0063] When the electric field is removed, an inverse concentration gradient temperature field is formed between the fresh water tank and the brine tank under the action of the geothermal heat, based on the Soret effect, the magnesium ions adhering and accumulating at the channel opening of the monovalent cation selective membrane will spontaneously migrate from the high-temperature side to the low-temperature side, thereby achieving the effect of membrane cleaning, compared with other membrane cleaning methods using electricity, the membrane cleaning method adopted by the present application can achieve zero energy consumption. Since the geothermal heat is used to heat the solution in the fresh water tank, the energy consumption for heating in the subsequent evaporation and precipitation lithium extraction step can be reduced.

[0064] Please refer to Figure 4 The temperature difference between the surface heat source and the super-shallow heat source is large, so when the super-shallow heat source is used, the pipeline in the surface layer, i.e. the temperature layer, should be vacuumized and heat-insulated to avoid affecting the temperature of the pipeline in the constant temperature layer.

[0065] Please refer to Figure 5 Under the action of the electric field, the positive magnesium ions and lithium ions migrate towards the cathode, after passing through the bipolar membrane, since the ion selective exchange membrane is a monovalent cation permeable membrane, a large number of magnesium ions accumulate at the entrance of the ion channel, the free magnesium ions combine with OH - to form Mg(OH)2 precipitate and adhere to the entrance of the channel, thereby forming membrane clogging and affecting the migration of lithium ions.

[0066] Among them, the external circuit adopts a constant voltage or constant current direct current electric field operation.

[0067] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0068] The present application is simulated by COMSOL 6.0, and the magnesium ion migration under the action of different temperature gradients of solutions under different concentration differences is obtained, as shown in FIGS. 1 to 3. Figure 6 As shown in FIGS. 1 to 3, when the concentration difference of the solution is 10 times, 30 times and 50 times respectively, the temperature of the fresh water tank gradually increases, and the temperature of the brine tank is maintained at 283K, that is, when the temperature difference between the two is increased from 10K to 30K, the influence of the 10K temperature difference on the magnesium ion migration is < the influence of the 20K temperature difference on the magnesium ion migration < the influence of the 30K temperature difference on the magnesium ion migration, and the specific values are shown in the following table:

[0069] Table 1 is the ion concentration at the entrance of the ion channel under the action of each temperature gradient under a 10-time concentration difference

[0070]

[0071] As can be seen from Table 1, as the temperature difference between the fresh water tank and the brine tank increases, the magnesium ion concentration attached to the entrance of the channel decreases, that is, under the action of the temperature gradient, the membrane is decontaminated.

[0072] Table 2 is the ion concentration at the entrance of the ion channel under the action of each temperature gradient under a 30-time concentration difference

[0073]

[0074] As can be seen from Table 2, as the temperature difference between the fresh water tank and the brine tank increases, the magnesium ion concentration attached to the entrance of the channel decreases, that is, under the action of the temperature gradient, the membrane is decontaminated.

[0075] Table 3 is the ion concentration at the entrance of the ion channel under the action of each temperature gradient under a 50-time concentration difference

[0076]

[0077] As can be seen from Table 3, with the increase of the temperature difference between the fresh water tank and the brine tank, the concentration of magnesium ions attached to the entrance of the pore channel is reduced, that is, under the action of the temperature gradient, the membrane pollution removal is realized.

[0078] In summary, the method for extracting lithium from a salt lake by electrodialysis based on shallow geothermal regulation and membrane pollution removal effectively combines the lithium extraction by electrodialysis with geothermal heat, strengthens the efficiency of the lithium extraction process, and reduces the energy consumption caused by the membrane clogging and pollution removal.

[0079] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for lithium extraction from salt lakes by electrodialysis based on shallow geothermal regulation and membrane decontamination, characterized in that, In summer, the surface ground source heat pipe is connected to the fresh water tank, the super-shallow ground source heat pipe is connected to the brine tank, and the desalination original solution containing a large amount of lithium ions and magnesium ions is stored in the brine tank as a desalination chamber of the electrodialysis process; in winter, the super-shallow ground source heat pipe is connected to the fresh water tank, and the surface ground source heat pipe is connected to the brine tank; the fresh water tank stores fresh water and collects lithium ions after desalination as a lithium ion recovery chamber of the electrodialysis process. When the power is on, the ions in the brine tank migrate directionally under the action of the electric field, the cations migrate to the cathode direction of the electric field, and the anions migrate to the anode direction of the electric field; the lithium ions pass through the monovalent cation selective membrane, and the magnesium ions are attached and accumulated on the surface and pore mouth of the monovalent cation selective membrane to form membrane blockage; after the electric field is removed, under the action of the ground source heat, a temperature field with an inverse concentration gradient is formed between the fresh water tank and the brine tank, the magnesium ions attached and accumulated on the cation selective membrane migrate from the high-temperature side to the low-temperature side, and a porous medium membrane is arranged between the fresh water tank and the brine tank; In summer, one end of the first brine tank is connected to the negative electrode of the power supply through the first fresh water tank, the other end is connected to the positive electrode of the power supply through the second fresh water tank, a first cation selective exchange membrane is arranged between the first brine tank and the first fresh water tank, a first anion selective membrane is arranged between the first brine tank and the second fresh water tank, the first fresh water tank and the second fresh water tank are connected to the surface ground source heat pipe, and the first brine tank is connected to the super-shallow ground source heat pipe; In winter, one end of the second brine tank is connected to the negative electrode of the power supply through the third fresh water tank, the other end is connected to the positive electrode of the power supply through the fourth fresh water tank, a second cation selective exchange membrane is arranged between the second brine tank and the third fresh water tank, a second anion selective membrane is arranged between the second brine tank and the fourth fresh water tank, the second brine tank is connected to the surface ground source heat pipe, and the third fresh water tank and the fourth fresh water tank are connected to the super-shallow ground source heat pipe.

2. The method according to claim 1, wherein the method is characterized in that, A vacuum heat insulation section is arranged at the connection between the super-shallow ground source heat pipe and the first brine tank.

3. The method for lithium extraction and membrane decontamination from saline lakes based on shallow geothermal regulation according to claim 1, characterized in that, A vacuum heat insulation section is arranged at the connection between the super-shallow ground source heat pipe and the third fresh water tank and the fourth fresh water tank.

4. The method according to claim 1, wherein the method is characterized in that, The external circuit connected to the power supply is operated by a constant voltage or constant current direct current electric field.

5. The method according to claim 2 or 3, wherein the shallow geothermal source heat regulation based electrodialysis lithium extraction and membrane desalination method is characterized in that, The vacuum heat insulation section of the super-shallow ground source heat pipe is located on the surface layer.

6. The method for lithium extraction and membrane fouling removal from salt lake by electrodialysis based on shallow geothermal regulation according to claim 1, characterized in that, The outer layer of the brine tank is coated or covered with a radiation-proof coating material to reduce the absorption of external radiation heat by the brine tank, and the outer layer of the fresh water tank is coated with a coating material that easily absorbs radiation to increase the absorption of external radiation heat by the fresh water tank.

7. The method according to claim 1 or 6, wherein the method is characterized in that, The brine tank and the fresh water tank are further increased in temperature difference between them under the combined action of the ground source heat and the radiation heat.

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