Salt lake lithium extraction device and lithium extraction method

Abstract

The present invention relates to the technical field of lithium extraction from salt lakes, and in particular, to a device for extracting lithium from salt lakes and a method for extracting lithium from salt lakes. The device for extracting lithium from salt lakes comprises a first electrolytic cell, a second electrolytic cell, a first liquid storage device, a second liquid storage device, a third liquid storage device and a heating device, wherein the first liquid storage device, the second cathode chamber and the first anode chamber are sequentially connected via a first pipeline to form a first circulation system, the second liquid storage device, the first cathode chamber and the second anode chamber are sequentially connected via a second pipeline to form a second circulation system, and the third liquid storage device, the first lithium extraction chamber and the second lithium extraction chamber are sequentially connected via a third pipeline to form a third circulation system. The above-mentioned lithium extraction device can realize automatic and continuous lithium extraction.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium extraction from salt lakes, and in particular to a device and method for extracting lithium from salt lakes. Background Art

[0002] Lithium has many excellent physical and chemical properties and is widely used in military fields, aerospace, and glass manufacturing. With the increase in demand for lithium, the development of lithium extraction technology has also received increasing attention. However, the lithium content in the earth's crust is low, and a large amount of lithium resources exist in salt lakes. Lithium extraction from salt lakes refers to the extraction of lithium ore from salt lakes. The commonly used methods for extracting lithium from salt lakes are precipitation, solvent extraction, and adsorption, but these methods all have defects such as complex extraction processes and high costs. To this end, researchers have gradually developed electrochemical lithium extraction technology.

[0003] The charging and discharging process of lithium batteries is essentially the process of lithium ions being inserted and removed from the battery structure. The principle of lithium extraction from salt lakes by the "electrochemical deintercalation method" is similar to the charging and discharging principle of lithium batteries. The main difference is that the electrolyte used in lithium batteries is generally pure lithium hexafluorophosphate (which can support Li + The characteristic of the "electrochemical deintercalation method" is that the battery material is placed in the brine of the salt lake for charging and discharging. During the charging process, the electrode material absorbs the lithium ions in the brine, and during the discharging process, the electrode material transfers the Li + Released into a specific desorption liquid to achieve the effect of separation and concentration.

[0004] However, the traditional "electrochemical deintercalation method" for lithium extraction has the following defects: 1. The amount of adsorbent loaded per unit diaphragm area is small and the adsorption capacity is low. In an electrolytic cell of a certain volume, after increasing the number of electrodes, the adsorption efficiency of the adsorbent far away from the diaphragm is low, and the farther the adsorbent is from the diaphragm, the lower the absorption / deintercalation rate; 2. The temperature conditions cannot be controlled, that is, the adsorbent cannot be heated, which greatly limits the lithium extraction rate in a low temperature environment; 3. After each absorption / deintercalation cycle, not only does the electrode need to be manually replaced, but it also needs to be rinsed to remove residual impurity ions. The operation process is cumbersome and cannot achieve automated continuous lithium extraction. Summary of the invention

[0005] Based on this, it is necessary to provide a salt lake lithium extraction device and a lithium extraction method that can increase the lithium extraction rate, has adjustable reaction temperature, and can realize automated and continuous lithium extraction.

[0006] In one aspect, the present invention provides a salt lake lithium extraction device, comprising:

[0007] A first electrolytic cell, wherein the electrolytic cell of the first electrolytic cell is sequentially separated into a first anode chamber, a first lithium extraction chamber, a first brine chamber and a first cathode chamber by a first cation exchange membrane, a first anion exchange membrane and a second cation exchange membrane;

[0008] A second electrolytic cell, wherein the electrolytic cell of the second electrolytic cell is sequentially separated into a second anode chamber, a second lithium extraction chamber, a second brine chamber, and a second cathode chamber via a third cation exchange membrane, a second anion exchange membrane, and a fourth cation exchange membrane;

[0009] A first liquid storage device, used for storing lithium-rich adsorption material;

[0010] A second liquid storage device for storing lithium-deficient adsorption material;

[0011] A third liquid storage device, used to store desorption liquid; and

[0012] A heating device, used to heat the first liquid storage device, the second liquid storage device and the third liquid storage device;

[0013] The first liquid storage device, the second cathode chamber and the first anode chamber form a first circulation system via a first pipeline to allow the lithium-rich adsorption material to flow; the second liquid storage device, the first cathode chamber and the second anode chamber form a second circulation system via a second pipeline to allow the lithium-deficient adsorption material to flow; the third liquid storage device, the first lithium extraction chamber and the second lithium extraction chamber form a third circulation system via a third pipeline to allow the desorption liquid to flow; and the first brine chamber and the second brine chamber are respectively circulated with salt lake brine via a fourth pipeline.

[0014] In one embodiment, the first anode chamber, the first cathode chamber, the second anode chamber and the second cathode chamber are each provided with a current collector, and the current collector is a block with a three-dimensional cross-hole structure, or the current collector is a block with a plurality of grooves, and a porous structure is provided on the side wall of the groove.

[0015] In one embodiment, the salt lake lithium extraction device also includes a first power supply and a second power supply, the first power supply is connected in series between the first anode chamber and the first cathode chamber, and the second power supply is connected in series between the second anode chamber and the second cathode chamber.

[0016] In one embodiment, the salt lake lithium extraction device also includes a fourth liquid storage device for storing salt lake brine.

[0017] In one embodiment, the first brine chamber and the second brine chamber are connected via a fourth pipe, so that the salt lake brine flows between the first brine chamber and the second brine chamber;

[0018] Optionally, a pump body is provided on the first pipeline, the second pipeline, the third pipeline and the fourth pipeline.

[0019] In one aspect, the present invention further provides a method for extracting lithium from a salt lake, which uses the above-mentioned salt lake lithium extraction device and comprises the following steps:

[0020] Allowing salt lake brine to flow through the first brine chamber and the second brine chamber, respectively, and filling the first liquid storage device, the second liquid storage device, and the third liquid storage device with lithium-rich adsorption material, lithium-deficient adsorption material, and desorption liquid, respectively;

[0021] The first electrolytic cell and the second electrolytic cell are started to allow the lithium-rich adsorption material, the lithium-deficient adsorption material and the desorption solution to flow in the first circulation system, the second circulation system and the third circulation system respectively; in the first circulation system, the lithium-rich adsorption material undergoes an oxidation reaction when flowing through the first anode chamber to convert Li + The lithium-deficient adsorption material is removed into the desorption liquid of the first lithium extraction chamber and converted into a lithium-deficient adsorption material. The lithium-deficient adsorption material undergoes a reduction reaction when flowing through the second cathode chamber and absorbs Li in the salt lake brine of the second brine chamber. + , and reform the lithium-rich adsorption material; in the second circulation system, the lithium-deficient adsorption material undergoes a reduction reaction when flowing through the first cathode chamber and absorbs Li in the salt lake brine in the first brine chamber + , and is converted into a lithium-rich adsorption material, which undergoes an oxidation reaction when flowing through the second anode chamber to convert Li + The lithium ions are removed into the desorption liquid of the second lithium extraction chamber and converted back into lithium-deficient adsorption material. Under the action of the first circulation system and the second circulation system, the lithium ions in the salt lake brine are removed. + Extraction complete.

[0022] In one embodiment, the desorption liquid is an inorganic salt solution;

[0023] Optionally, the inorganic salt solution includes one or more of a chloride solution, a carbonate solution, a sulfate solution and a phosphate solution.

[0024] In one embodiment, the method for extracting lithium from a salt lake satisfies at least one of the following characteristics:

[0025] (1) The lithium-rich adsorption material is a positive electrode material for a lithium battery;

[0026] Optionally, the lithium battery positive electrode material includes LiFePO4, LiMn2O4, Li4Ti5O 12 , LiCoO2 and LiVO3;

[0027] (2) The lithium-deficient adsorption material is a lithium-depleted lithium battery positive electrode material;

[0028] Optionally, the lithium-free lithium battery positive electrode material includes FePO4, Li 1-x Mn2O4、Li 4-x Ti5O 12 , Li 1- x CoO2 and Li 1-x One or more of VO3.

[0029] In one embodiment, the solid contents of the lithium-rich adsorption material and the lithium-deficient adsorption material are independently 20 g / L to 100 g / L.

[0030] In one embodiment, the voltages applied by the first power supply and the second power supply are independently 0.2V~1.0V.

[0031] The above-mentioned salt lake lithium extraction device can enable the lithium-rich adsorption material to continuously transfer its own Li + Released into the desorption solution, the lithium-deficient adsorption material continuously absorbs Li + Transmembrane adsorption is carried out to achieve the purpose of extracting lithium from salt lake brine.

[0032] Selecting a flowing desorption liquid as the adsorbent and placing it in the third liquid storage device can not only avoid the problems of low loading and low absorption / desorption rate of traditional solid adsorbents, but also heat it through a heating device, so as to achieve rapid lithium extraction at any temperature, especially at low temperature. The desorption liquid and salt lake brine are separated by a cation exchange membrane, so that the lithium-rich adsorption material circulates in the first circulation system, achieving its Li removal through the first cation exchange membrane. + To the desorption solution, Li + The lithium-deficient adsorption material circulates in the second circulation system, achieving the adsorption of Li + Through the third cation exchange membrane, Li + The above process realizes the desorption of Li + The adsorption and desorption are carried out through transmembrane adsorption and desorption rather than through direct contact with salt lake brine and desorption liquid, thus avoiding the step of cleaning the adsorbent after the adsorption / desorption cycle, further improving the lithium extraction rate and avoiding manual operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 This is a schematic diagram of the structure of a salt lake lithium extraction device in one embodiment of the present invention;

[0035] Figure 2 This is a schematic diagram of the structure of a salt lake lithium extraction device in another embodiment of the present invention.

[0036] Explanation of the reference numerals: 100, first electrolytic cell; 101, first cation exchange membrane; 102, first anion exchange membrane; 103, second cation exchange membrane; 104, first anode chamber; 105, first lithium extraction chamber; 106, first brine chamber; 107, first cathode chamber; 108, first power supply; 109, first pipeline; 110, second pipeline; 111, third pipeline; 112, fourth pipeline; 200, second electrolytic cell; 201, third cation exchange membrane; 202, second anion exchange membrane; 203, fourth cation exchange membrane; 204, second anode chamber; 205, second lithium extraction chamber; 206, second brine chamber; 207, second cathode chamber; 208, second power supply; 300, first liquid storage device; 400, second liquid storage device; 500, third liquid storage device; 600, heating device; 700, fourth liquid storage device; 800, pump body. DETAILED DESCRIPTION

[0037] References to embodiments of the present invention will now be provided in detail, one or more examples of which are described below. Each example is provided as an explanation rather than a limitation of the present invention. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made to the present invention without departing from the scope or spirit of the present invention. For example, a feature illustrated or described as part of one embodiment may be used in another embodiment to produce a further embodiment.

[0038] Therefore, it is intended that the present invention covers such modifications and variations that fall within the scope of the appended claims and their equivalents. Other objects, features and aspects of the present invention are disclosed in or are obvious from the following detailed description. Those of ordinary skill in the art will appreciate that this discussion is only a description of exemplary embodiments and is not intended to limit the broader aspects of the present invention.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0040] It is understandable that the adsorbent of the conventional salt lake lithium extraction device is solid and has a low loading capacity, resulting in a low lithium extraction rate. Moreover, after the absorption / desorption cycle, the adsorbent needs to be reversed and cleaned, which is complicated to operate and cannot achieve automatic continuous lithium extraction. To this end, the present invention provides a salt lake lithium extraction device, which can enable the lithium-rich adsorbent to continuously transfer its own Li + Released into the desorption solution, the lithium-deficient adsorption material continuously absorbs Li + Transmembrane adsorption is performed to achieve the purpose of extracting lithium from salt lake brine. The fluid desorption liquid is selected as the adsorbent and placed in the third liquid storage device 500, which can not only avoid the problems of low loading and low absorption / desorption rate of traditional solid adsorbents, but also can be heated by the heating device 600, so that rapid lithium extraction can be achieved at any temperature, especially at low temperature. The desorption liquid and salt lake brine are separated by a cation exchange membrane, so that the lithium-rich adsorption material circulates in the first circulation system, achieving its removal of Li through the first cation exchange membrane 101. + To the desorption liquid, the fourth cation exchange membrane 203 is used to remove Li + The lithium-deficient adsorption material circulates in the second circulation system, achieving the adsorption of Li by the second cation exchange membrane 103. + Through the third cation exchange membrane 201, Li + The above process realizes the desorption of Li + The adsorption and desorption are carried out through transmembrane adsorption and desorption rather than through direct contact with salt lake brine and desorption liquid, thus avoiding the step of cleaning the adsorbent after the adsorption / desorption cycle, further improving the lithium extraction rate and avoiding manual operation.

[0041] In the initial stage of the electrolysis reaction, the lithium-rich adsorbent material in the first liquid storage device 300 is continuously converted into the lithium-deficient adsorbent material in the first anode chamber 104, forming a mixed solution of the lithium-rich adsorbent material and the lithium-deficient adsorbent material. As the reaction time progresses, the proportion of the lithium-rich adsorbent material in the mixed solution gradually decreases, and the proportion of the lithium-deficient adsorbent material gradually increases. When the lithium-deficient adsorbent material in the mixed solution reaches a certain proportion, when it flows through the second cathode chamber 207, the lithium-deficient adsorbent material therein will begin to undergo a reduction reaction and be converted back into the lithium-rich adsorbent material, and the reaction rate increases with the increase in the proportion of the lithium-deficient adsorbent material in the mixed solution. During this process, the conversion rate of the lithium-rich adsorbent material in the first liquid storage device 300 to the lithium-deficient adsorbent material changes from fast to slow, and the conversion rate of the lithium-deficient adsorbent material to the lithium-rich adsorbent material changes from slow to fast. After a certain period of time, the conversion rates of the two will achieve a "dynamic balance". At this time, the first liquid storage device 300 contains a mixed solution with a constant ratio of lithium-rich adsorbent material and lithium-deficient adsorbent material, and the lithium-rich adsorbent material therein continuously releases Li in the first anode chamber 104. + To the first lithium extraction chamber 105, the lithium-deficient adsorption material in the second cathode chamber 207 continuously removes the Li + The cross-membrane adsorption is carried out into the lithium-deficient adsorption material, and the reaction rates of the two are in a dynamic equilibrium state, which can keep the mixed solution with a stable composition.

[0042] At the same time, in the initial stage of the reaction, the lithium-deficient adsorbent material in the third liquid storage device 500 is continuously converted into lithium-rich adsorbent material in the first cathode chamber 107, forming a mixed solution of lithium-rich adsorbent material and lithium-deficient adsorbent material. As the reaction time progresses, the proportion of lithium-deficient adsorbent material in the mixed solution gradually decreases, and the proportion of lithium-rich adsorbent material gradually increases. When the lithium-rich adsorbent material in the mixed solution reaches a certain proportion, when it flows through the second anode chamber 204, the lithium-rich adsorbent material therein begins to undergo an oxidation reaction, removing Li + When it reaches the second lithium extraction chamber 205, it is converted back into a lithium-deficient adsorbent material, and the reaction rate increases with the increase in the proportion of lithium-rich adsorbent material in the mixed solution. In this process, the conversion rate of the lithium-deficient adsorbent material to the lithium-rich adsorbent material in the third liquid storage device 500 changes from fast to slow, and the conversion rate of the lithium-rich adsorbent material to the lithium-deficient adsorbent material changes from slow to fast. After a certain period of time, the conversion rates of the two achieve a "dynamic balance". At this time, the ratio of the lithium-rich adsorbent material to the lithium-deficient adsorbent material in the third liquid storage device 500 is constant, and the lithium-deficient adsorbent material in the first cathode chamber 107 continuously converts the Li in the first brine chamber 106 into lithium-rich adsorbent material. + The lithium-rich adsorption material in the second anode chamber 204 continuously absorbs Li +The cross-membrane detachment into the desorption liquid is carried out, and the reaction rates of the two are equal, so the composition of the mixed liquid can be kept stable.

[0043] After the mixed liquids in the first liquid storage device 300 and the third liquid storage device 500 reach the dynamic equilibrium of absorption / desorption, they can continuously transfer the Li + The lithium is extracted into the desorption solution for enrichment, thus realizing automated and continuous lithium extraction.

[0044] See also Figure 1 The first object of the present invention is to provide a salt lake lithium extraction device, which includes a first electrolytic cell 100, a second electrolytic cell 200, a first liquid storage device 300, a second liquid storage device 400, a third liquid storage device 500 and a heating device 600. Wherein:

[0045] The electrolytic cell of the first electrolytic cell 100 is sequentially separated into a first anode chamber 104, a first lithium extraction chamber 105, a first brine chamber 106 and a first cathode chamber 107 by a first cation exchange membrane 101, a first anion exchange membrane 102 and a second cation exchange membrane 103;

[0046] The electrolytic cell of the second electrolytic cell 200 is sequentially separated into a second anode chamber 204, a second lithium extraction chamber 205, a second brine chamber 206 and a second cathode chamber 207 by a third cation exchange membrane 201, a second anion exchange membrane 202 and a fourth cation exchange membrane 203;

[0047] The first liquid storage device 300 is used to store lithium-rich adsorption material;

[0048] The second liquid storage device 400 is used to store lithium-deficient adsorption material;

[0049] The third liquid storage device 500 is used to store desorption liquid;

[0050] The heating device 600 is used to heat the first liquid storage device 300, the second liquid storage device 400 and the third liquid storage device 500;

[0051] The first liquid storage device 300, the second cathode chamber 207 and the first anode chamber 104 form a first circulation system via the first pipeline 109 to allow the lithium-rich adsorption material to circulate; the second liquid storage device 400, the first cathode chamber 107 and the second anode chamber 204 form a second circulation system via the second pipeline 110 to allow the lithium-deficient adsorption material to circulate; the third liquid storage device 500, the first lithium extraction chamber 105 and the second lithium extraction chamber 205 form a third circulation system via the third pipeline 111 to allow the desorption liquid to circulate, and the first brine chamber 106 and the second brine chamber 206 are respectively circulated with salt lake brine via the fourth pipeline 112.

[0052] In some embodiments, a current collector is provided in the first anode chamber 104, the first cathode chamber 107, the second anode chamber 204, and the second cathode chamber 207. The current collector is a block having a three-dimensional cross-hole structure, or the current collector is a block having a plurality of grooves, and a porous structure is provided on the side wall of the groove. Preferably, the plurality of grooves are arranged in parallel on the same plane of the current collector. The above-mentioned arrangement of the structure of the current collector can increase the specific surface area and internal electric field coverage of the current collector, promote the circulation of lithium-rich adsorbent materials and lithium-deficient adsorbent materials in the current collector, and increase the frequency of contact between the lithium-rich adsorbent materials and the lithium-deficient adsorbent materials and the current collector.

[0053] The material of the current collector is not limited, and an inert material with strong conductivity and no reaction with the lithium-rich adsorption material and the lithium-deficient adsorption material is selected, for example, titanium, graphite or nickel.

[0054] In some embodiments, the effective area of ​​the first cation exchange membrane 101, the first anion exchange membrane 102, the second cation exchange membrane 103, the third cation exchange membrane 201, the second anion exchange membrane 202, and the fourth cation exchange membrane 203 may be 0.16 m 2 ~0.25m 2 .

[0055] It can be understood that the salt lake lithium extraction device can also include a first power supply 108 and a second power supply 208, the first power supply 108 is connected in series between the first anode chamber 104 and the first cathode chamber 107, and the second power supply 208 is connected in series between the second anode chamber 204 and the second cathode chamber 207. By providing the first power supply 108 and the second power supply 208, the first electrolytic cell 100 and the second electrolytic cell 200 can be provided with the power required for electrolysis.

[0056] In some embodiments, the salt lake lithium extraction device further includes a fourth liquid storage device 700 for storing salt lake brine.

[0057] Please also read Figure 2 In some embodiments, the first brine chamber 106 and the second brine chamber 206 may be connected via a fourth pipe 112 to allow salt lake brine to flow between the first brine chamber 106 and the second brine chamber 206 .

[0058] Preferably, a pump body 800 may be further provided on the first pipeline 109, the second pipeline 110, the third pipeline 111 and the fourth pipeline 112. By adding the pump body 800, the desorption liquid, the salt lake brine, the lithium-rich adsorption material and the lithium-deficient adsorption material can flow smoothly in the pipeline. The pump body 800 may be a magnetic pump.

[0059] In one aspect, the present invention further provides a method for extracting lithium from a salt lake, which uses the above-mentioned salt lake lithium extraction device and comprises the following steps:

[0060] The salt lake brine is made to flow through the first brine chamber 106 and the second brine chamber 206, respectively, and the lithium-rich adsorption material, the lithium-deficient adsorption material and the desorption liquid are respectively filled in the first liquid storage device 300, the second liquid storage device 400 and the third liquid storage device 500;

[0061] The first electrolytic cell 100 and the second electrolytic cell 200 are started, and the lithium-rich adsorption material, the lithium-deficient adsorption material and the desorption liquid are circulated in the first circulation system, the second circulation system and the third circulation system respectively; in the first circulation system, the lithium-rich adsorption material undergoes an oxidation reaction when flowing through the first anode chamber 104 to convert Li + The lithium-deficient adsorption material is removed into the desorption liquid of the first lithium extraction chamber 105 and converted into a lithium-deficient adsorption material. The lithium-deficient adsorption material undergoes a reduction reaction when flowing through the second cathode chamber 207 and absorbs Li in the salt lake brine of the second brine chamber 206. + , and re-form the lithium-rich adsorption material; in the second circulation system, the lithium-deficient adsorption material undergoes a reduction reaction when flowing through the first cathode chamber 107 and absorbs Li in the salt lake brine in the first brine chamber 106 + , and is converted into a lithium-rich adsorption material. The lithium-rich adsorption material undergoes an oxidation reaction when flowing through the second anode chamber 204 to convert Li + The lithium ions are removed into the desorption liquid of the second lithium extraction chamber 205 and converted back into lithium-deficient adsorption material. Under the action of the first circulation system and the second circulation system, the lithium ions in the salt lake brine are removed. + Extraction complete.

[0062] In some embodiments, the desorption liquid may be any liquid commonly used in the art for collecting, enriching or concentrating high-purity lithium solutions, such as an inorganic salt solution;

[0063] It can be understood that the inorganic salt solution can be one or more of a chloride solution, a carbonate solution, a sulfate solution and a phosphate solution.

[0064] In some embodiments, the lithium-rich adsorption material can be selected from materials commonly used in the art, such as lithium battery positive electrode materials, which can include LiFePO4, LiMn2O4, Li4Ti5O 12 , LiCoO2 and LiVO3 or more.

[0065] In some embodiments, the lithium-deficient adsorption material may also be selected from materials commonly used in the art, such as lithium-depleted lithium battery positive electrode materials, which may include FePO4, Li 1-x Mn2O4、Li 4- x Ti5O 12 , Li1-x CoO2 and Li 1-x One or more of VO3, wherein 0≤x≤1.

[0066] In some embodiments, the solid contents of the lithium-rich adsorption material and the lithium-deficient adsorption material may be independently 20 g / L to 100 g / L.

[0067] It is understood that in order to improve the conductivity of the lithium-rich adsorption material and the lithium-deficient adsorption material, they can be mixed with a conductive additive, wherein the mass percentage of the conductive additive can be 2% to 20%, and the conductive additive can be one or more of conductive carbon powder, conductive metal powder, graphene and carbon nanotubes.

[0068] It can be understood that in order to improve the conductivity of the electrode liquid formed by the lithium-rich adsorption material and the lithium-deficient adsorption material, they can be mixed with an inorganic salt electrolyte, wherein the concentration of the inorganic salt electrolyte can be 0.05 mol / L~1.0 mol / L.

[0069] In some embodiments, the flow rates of the lithium-rich adsorption material, the lithium-deficient adsorption material, the desorption solution, and the salt lake brine may be independently 20 mL / min to 500 mL / min.

[0070] In some embodiments, the salt lake brine may include at least lithium ions, and may also include one or more of magnesium ions, potassium ions, sodium ions, and aluminum ions.

[0071] In some embodiments, during the electrolysis process, the voltages applied by the first power source 108 and the second power source 208 to the first electrolytic cell 100 and the second electrolytic cell 200 may be independently 0.1V to 1V, respectively.

[0072] In some embodiments, the electrolysis reaction time can be 8h~12h.

[0073] The present invention is further described in detail below with reference to specific embodiments and comparative examples. Example 1

[0074] like Figure 2 As shown, the salt lake lithium extraction device provided in this embodiment includes a first electrolytic cell 100, a second electrolytic cell 200, a first liquid storage device 300, a second liquid storage device 400, a third liquid storage device 500, a fourth liquid storage device 700 and a heating device 600. Among them,

[0075] The electrolytic cell of the first electrolytic cell 100 is separated into a first anode chamber 104, a first lithium extraction chamber 105, a first brine chamber 106 and a first cathode chamber 107 by a first cation exchange membrane 101, a first anion exchange membrane 102 and a second cation exchange membrane 103 in sequence. The first power supply 108 is connected in series between the first anode chamber 104 and the first cathode chamber 107. The electrolytic cell of the second electrolytic cell 200 is separated into a second anode chamber 204, a second lithium extraction chamber 205, a second brine chamber 206 and a second cathode chamber 207 by a third cation exchange membrane 201, a second anion exchange membrane 202 and a fourth cation exchange membrane 203 in sequence. The second power supply 208 is connected in series between the second anode chamber 204 and the second cathode chamber 207. A current collector is provided in the first anode chamber 104, the second anode chamber 204, the first cathode chamber 107 and the second cathode chamber 207, and the current collector is a graphite block with a three-dimensional cross hole structure. The electrolytic cells of the first electrolytic cell 100 and the second electrolytic cell 200 are both made of graphite. The first liquid storage device 300 stores lithium-rich adsorption material, the second liquid storage device 400 stores lithium-deficient adsorption material, the third liquid storage device 500 stores desorption liquid, and the fourth liquid storage device 700 stores salt lake brine. A heating device 600 is used to heat the first liquid storage device 300, the second liquid storage device 400, the third liquid storage device 500 and the fourth liquid storage device 700. Salt lake brine flows through the first brine chamber 106 and the second brine chamber 206 respectively; the first liquid storage device 300, the second cathode chamber 207 and the first anode chamber 104 form a first circulation system via the first pipeline 109 in sequence to allow the lithium-rich adsorption material to flow; the second liquid storage device 400, the first cathode chamber 107 and the second anode chamber 204 form a second circulation system via the second pipeline 110 in sequence to allow the lithium-deficient adsorption material to flow; the third liquid storage device 500, the first lithium extraction chamber 105 and the second lithium extraction chamber 205 form a third circulation system via the third pipeline 111 in sequence to allow the desorption liquid to flow; the first brine chamber 106 and the second brine chamber 206 are connected via the fourth pipeline 112 to allow the salt lake brine to flow.

[0076] In this embodiment, the volume of the lithium-rich adsorption material electrode liquid is 500mL, wherein the active material is LiFePO4, the solid content is 50g / L, and the concentration of NaCl is 0.1mol / L; the volume of the lithium-deficient adsorption material electrode liquid is 500ml, wherein the active material is FePO4, the solid content is 50g / L, and the concentration of NaCl is 0.1mol / L; the original mass ratio of the lithium-rich adsorption material to the lithium-deficient adsorption material is 1:1; the desorption liquid is a NaCl solution with a volume of 1L and a concentration of 0.1mol / L; the volume of salt lake brine is 5L, which includes lithium ions with a concentration of 220.1mg / L, magnesium ions with a concentration of 58.2g / L, potassium ions with a concentration of 32.5g / L and sodium ions with a concentration ratio of magnesium ions to lithium ions of 264; the effective areas of the first cation exchange membrane 101, the first anion exchange membrane 102, the second cation exchange membrane 103, the third cation exchange membrane 201, the second anion exchange membrane 202 and the fourth cation exchange membrane 203 are all 0.16m 2 ; The output voltages of the first power supply 108 and the second power supply 208 are both 0.3V; the heating device 600 is controlled to maintain the temperature of the first liquid storage device 300, the second liquid storage device 400, the third liquid storage device 500 and the fourth liquid storage device 700 at 23°C. The pump body 800 is operated to maintain the flow rate of the lithium-rich adsorption material, the lithium-deficient adsorption material, the desorption liquid and the salt lake brine at 120mL / min. After 4.2 hours of power-on, the currents of the first electrolytic cell 100 and the second electrolytic cell 200 are consistent, and the lithium ion enrichment rates in the first lithium extraction chamber 105 and the second lithium extraction chamber 205 are equal, and it can be judged that the reaction has reached dynamic equilibrium. During the 4.2h~8h power-on process, due to the continuous decrease in the lithium ion concentration in the brine, the currents of the two electrolytic cells began to decrease synchronously at the same time, that is, they remained equal in value, and the lithium ion enrichment rates were still equal. After 8 hours of reaction time, the mass ratio of LiFePO4 to FePO4 in the first liquid storage device 300 and the second liquid storage device 400 was measured to be 1:1.46, the lithium ion concentration in the salt lake brine decreased to 131.6 mg / L, and the lithium ion concentration in the desorption liquid increased from 0 to 423.9 mg / L. The lithium ion migration rate per unit membrane area was calculated to be 0.331 g / m 2 h, and the lithium ion recovery rate was 38.5%. Example 2

[0077] The lithium extraction method of this embodiment is basically the same as that of embodiment 1, except that the solid content of the lithium-rich adsorption material and the lithium-deficient adsorption material is 120 g / L. After 4.0 hours of power-on, the reaction reaches a dynamic equilibrium. After 8 hours of reaction time, the mass ratio of LiFePO4 and FePO4 in the first liquid storage device 300 and the second liquid storage device 400 is measured to be 1:1.43. The lithium ion concentration in the salt lake brine is measured to drop to 62.8 mg / L, and the lithium ion concentration in the desorption liquid increases from 0 to 778.5 mg / L. The lithium ion migration rate per unit membrane area is calculated to be 0.607 g / m 2 h, the lithium ion recovery rate is 70.7%. Example 3

[0078] The lithium extraction method of this embodiment is basically the same as that of embodiment 2, except that the salt lake brine includes lithium ions at a concentration of 660.4 mg / L, magnesium ions at a concentration of 13.5 g / L, potassium ions at a concentration of 5.9 g / L, aluminum ions at a concentration of 762.2 mg / L, and sodium ions at a concentration of 23.8 g / L, and the concentration ratio of magnesium ions to lithium ions is 20.5. After 1.2 hours of power-on, the reaction reaches a dynamic equilibrium. After the reaction time of 8 hours, the mass ratio of LiFePO4 and FePO4 in the first liquid storage device 300 and the second liquid storage device 400 is measured to be 1:1.28. The lithium ion concentration in the salt lake brine is measured to drop to 354.0 mg / L, and the lithium ion concentration in the desorption solution increases from 0 to 1530.1 mg / L. The lithium ion migration rate per unit membrane area is calculated to be 1.195 g / m 2 h, and the lithium ion recovery rate was 46.4%. Example 4

[0079] The lithium extraction method of this embodiment is basically the same as that of embodiment 1, except that: the lithium-rich adsorption material is LiMn2O4, and the lithium-deficient adsorption material is Li 1-x Mn2O4, x is 0.8. After 2.5 hours of power on, the reaction reached a dynamic equilibrium. After 8 hours of reaction time, the LiMn2O4 and Li 1-x The mass ratio of Mn2O4 is 1:0.95. The lithium ion concentration in the salt lake brine is measured to drop to 95.2 mg / L, and the lithium ion concentration in the desorption solution increases from 0 to 617.3 mg / L. The lithium ion migration rate per unit membrane area is calculated to be 0.482 g / m 2 h, and the lithium ion recovery rate was 56.7%. Example 5

[0080] The lithium extraction method of this embodiment is basically the same as that of embodiment 4, except that the current collector is a one-piece graphite block with multiple grooves, and a porous structure is provided on the side wall of each groove. After 1.0h of power supply, the reaction reaches a dynamic equilibrium. After 8h of reaction time, the LiMn2O4 and Li in the first liquid storage device 300 and the second liquid storage device 400 are measured. 1-x The mass ratio of Mn2O4 is 1:0.92. The lithium ion concentration in the salt lake brine is measured to drop to 32.5 mg / L, and the lithium ion concentration in the desorption solution increases from 0 to 935.2 mg / L. The lithium ion migration rate per unit membrane area is calculated to be 0.729 g / m 2 h, the lithium ion recovery rate was 84.9%. Example 6

[0081] The lithium extraction method of this embodiment is basically the same as that of embodiment 1, except that: the lithium-rich adsorption material is Li4Ti5O 12 , the lithium-deficient adsorption material is Li 4-x Ti5O 12 , x is 2.8. After 2.4 hours of power on, the reaction reached a dynamic equilibrium. After 8 hours of reaction time, the Li4Ti5O in the first liquid storage device 300 and the second liquid storage device 400 were measured. 12 and Li 4-x Ti5O 12 The mass ratio of is 1:0.66. The lithium ion concentration in the salt lake brine was measured to drop to 15.4 mg / L, and the lithium ion concentration in the desorption solution increased from 0 to 1014.6 mg / L. The lithium ion migration rate per unit membrane area was calculated to be 0.528 g / m 2 h, the lithium ion recovery rate is 92.9%. Example 7

[0082] The lithium extraction method of this embodiment is basically the same as that of embodiment 4, except that: the electrode liquid of the lithium-rich adsorption material and the electrode liquid of the lithium-deficient adsorption material both contain 0.5 mol / L NaCl to provide basic conductivity. After 5.2 hours of power supply, the reaction reaches a dynamic equilibrium. After the reaction time of 8 hours, the LiMn2O4 and Li in the first liquid storage device 300 and the second liquid storage device 400 are measured. 1-x The mass ratio of Mn2O4 is 1:0.9. The lithium ion concentration in the salt lake brine is measured to drop to 48.3 mg / L, and the lithium ion concentration in the desorption solution increases from 0 to 862.8 mg / L. The lithium ion migration rate per unit membrane area is calculated to be 0.673 g / m 2 h, the lithium ion recovery rate is 78.1%. Example 8

[0083] The lithium extraction method of this embodiment is basically the same as that of embodiment 3, except that the temperature of the first liquid storage device 300, the second liquid storage device 400 and the third liquid storage device 500 is maintained at 50°C, and the temperature of the fourth liquid storage device 700 is maintained at 23°C. After 0.3h of power-on, the reaction reaches a dynamic equilibrium. After 8h of reaction time, the mass ratio of LiFePO4 and FePO4 in the first liquid storage device 300 and the second liquid storage device 400 is measured to be 1:1.2. The lithium ion concentration in the salt lake brine is measured to drop to 262.5mg / L, and the lithium ion concentration in the desorption liquid increases from 0 to 1976.4mg / L. The lithium ion migration rate per unit membrane area is calculated to be 1.544g / m 2 h, and the lithium ion recovery rate was 60.3%. Example 9

[0084] The lithium extraction method of this embodiment is basically the same as that of embodiment 4, except that the output voltage of the first power supply 108 and the second power supply 208 are both 0.5V. After 3.5 hours of power supply, the reaction reaches a dynamic equilibrium. After 8 hours of reaction time, the LiMn2O4 and Li in the first liquid storage device 300 and the second liquid storage device 400 are measured. 1-x The mass ratio of Mn2O4 is 1:0.92. The lithium ion concentration in the salt lake brine was measured to drop to 12.7 mg / L, and the lithium ion concentration in the desorption solution increased from 0 to 1032.0 mg / L. The lithium ion migration rate per unit membrane area was calculated to be 0.806 g / m 2 h, and the lithium ion recovery rate was 94.2%. Example 10

[0085] The lithium extraction method of this embodiment is basically the same as that of embodiment 3, except that the lithium-rich adsorption material and the lithium-deficient adsorption material are both doped with 5% conductive carbon powder by mass. After 0.8h of power-on, the reaction reaches a dynamic equilibrium. After the reaction time of 8h, the mass ratio of LiFePO4 and FePO4 in the first liquid storage device 300 and the second liquid storage device 400 is measured to be 1:1.49. The lithium ion concentration in the salt lake brine is measured to drop to 308.2mg / L, and the lithium ion concentration in the desorption liquid increases from 0 to 1770.1mg / L. The lithium ion migration rate per unit membrane area is calculated to be 1.383g / m 2 h, and the lithium ion recovery rate was 53.3%. Embodiment 11

[0086] The lithium extraction method of this embodiment is basically the same as that of embodiment 5, except that the volume of salt lake brine is 30L and the electrolysis reaction time is 36h. After 0.5h of power on, the reaction reaches a dynamic equilibrium. After the reaction time of 36h, the LiMn2O4 and Li in the first liquid storage device 300 and the second liquid storage device 400 are measured. 1-xThe mass ratio of Mn2O4 is 1:0.86. The lithium ion concentration in the salt lake brine is measured to drop to 28.5 mg / L, and the lithium ion concentration in the desorption solution increases from 0 to 3.81 g / L. The lithium ion migration rate per unit membrane area is calculated to be 0.638 g / m 2 h, the lithium ion recovery rate was 87.1%. Comparative Example 1

[0087] The lithium extraction method of this comparative example is basically the same as that of Example 1, except that the current collector is a graphite block with grooves, and the grooves are filled with a titanium three-dimensional mesh. After 6.8 hours of power-on, the reaction reaches a dynamic equilibrium. After the 8-hour reaction time, the mass ratio of LiFePO4 and FePO4 in the first liquid storage device 300 and the second liquid storage device 400 is measured to be 1:0.92. The lithium ion concentration in the salt lake brine is measured to drop to 157.3 mg / L, and the lithium ion concentration in the desorption liquid increases from 0 to 311.8 mg / L. The lithium ion migration rate per unit membrane area is calculated to be 0.245 g / m 2 h, and the lithium ion recovery rate was 28.5%. Comparative Example 2

[0088] The lithium extraction method of this comparative example is basically the same as that of Example 5, except that the first electrolytic cell 100 and the second electrolytic cell 200 are both in a low temperature environment, and the temperature of the first liquid storage device 300, the second liquid storage device 400, the third liquid storage device 500 and the fourth liquid storage device 700 is maintained at 0°C. After 4.2 hours of power-on, the reaction reaches a dynamic equilibrium. After the reaction time of 8 hours, the LiMn2O4 and Li in the first liquid storage device 300 and the second liquid storage device 400 are measured. 1-x The mass ratio of Mn2O4 is 1:0.92. The lithium ion concentration in the salt lake brine is measured to drop to 101.4 mg / L, and the lithium ion concentration in the desorption solution increases from 0 to 590.8 mg / L. The lithium ion migration rate per unit membrane area is calculated to be 0.463 g / m 2 h, and the lithium ion recovery rate was 53.9%.

[0089] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0090] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A device for extracting lithium from a salt lake, characterized in that: include: A first electrolytic cell, wherein the electrolytic cell of the first electrolytic cell is sequentially separated into a first anode chamber, a first lithium extraction chamber, a first brine chamber and a first cathode chamber by a first cation exchange membrane, a first anion exchange membrane and a second cation exchange membrane; A second electrolytic cell, wherein the electrolytic cell of the second electrolytic cell is sequentially separated into a second anode chamber, a second lithium extraction chamber, a second brine chamber, and a second cathode chamber via a third cation exchange membrane, a second anion exchange membrane, and a fourth cation exchange membrane; A first liquid storage device, used for storing lithium-rich adsorption material; A second liquid storage device for storing lithium-deficient adsorption material; A third liquid storage device, used for storing desorption liquid; as well as A heating device, used to heat the first liquid storage device, the second liquid storage device and the third liquid storage device; The first liquid storage device, the second cathode chamber and the first anode chamber form a first circulation system via a first pipeline to allow the lithium-rich adsorption material to flow; the second liquid storage device, the first cathode chamber and the second anode chamber form a second circulation system via a second pipeline to allow the lithium-deficient adsorption material to flow; the third liquid storage device, the first lithium extraction chamber and the second lithium extraction chamber form a third circulation system via a third pipeline to allow the desorption liquid to flow; and the first brine chamber and the second brine chamber are respectively circulated with salt lake brine via a fourth pipeline.

2. The salt lake lithium extraction device according to claim 1, characterized in that: The first anode chamber, the first cathode chamber, the second anode chamber and the second cathode chamber are all provided with current collectors, and the current collectors are blocks with a three-dimensional cross-hole structure, or the current collectors are blocks with multiple grooves, and the side walls of the grooves are provided with a porous structure.

3. The salt lake lithium extraction device according to claim 1, characterized in that: The salt lake lithium extraction device also includes a first power supply and a second power supply, wherein the first power supply is connected in series between the first anode chamber and the first cathode chamber, and the second power supply is connected in series between the second anode chamber and the second cathode chamber.

4. The device for extracting lithium from salt lake according to any one of claims 1 to 3, characterized in that: The salt lake lithium extraction device also includes a fourth liquid storage device for storing salt lake brine.

5. The salt lake lithium extraction device according to any one of claims 1 to 3, characterized in that: The first brine chamber and the second brine chamber are connected via a fourth pipe so that the salt lake brine flows between the first brine chamber and the second brine chamber; Optionally, a pump body is provided on the first pipeline, the second pipeline, the third pipeline and the fourth pipeline.

6. A method for extracting lithium from a salt lake, characterized in that: The salt lake lithium extraction device according to any one of claims 1 to 5 comprises the following steps: Allowing salt lake brine to flow through the first brine chamber and the second brine chamber, respectively, and filling the first liquid storage device, the second liquid storage device, and the third liquid storage device with lithium-rich adsorption material, lithium-deficient adsorption material, and desorption liquid, respectively; Starting the first electrolytic cell and the second electrolytic cell, so that the lithium-rich adsorption material, the lithium-deficient adsorption material and the desorption liquid flow in the first circulation system, the second circulation system and the third circulation system respectively; In the first circulation system, the lithium-rich adsorption material undergoes an oxidation reaction when flowing through the first anode chamber to convert Li + The lithium-deficient adsorption material is desorbed into the desorption liquid of the first lithium extraction chamber and converted into a lithium-deficient adsorption material. The lithium-deficient adsorption material undergoes a reduction reaction when flowing through the second cathode chamber and absorbs Li in the salt lake brine of the second brine chamber. + , and reform the lithium-rich adsorption material; in the second circulation system, the lithium-deficient adsorption material undergoes a reduction reaction when flowing through the first cathode chamber and absorbs Li in the salt lake brine in the first brine chamber + , and is converted into a lithium-rich adsorption material, which undergoes an oxidation reaction when flowing through the second anode chamber to convert Li + The lithium-free adsorption material is then converted into the lithium-deficient adsorption material in the desorption solution of the second lithium extraction chamber. ... + Extraction complete.

7. The method for extracting lithium from salt lake according to claim 6, characterized in that: The desorption liquid is an inorganic salt solution; Optionally, the inorganic salt solution includes one or more of a chloride solution, a carbonate solution, a sulfate solution and a phosphate solution.

8. The method for extracting lithium from salt lake according to claim 6, characterized in that: Meet at least one of the following characteristics: (1) The lithium-rich adsorption material is a positive electrode material for a lithium battery; Optionally, the lithium battery positive electrode material includes LiFePO4, LiMn2O4, Li4Ti5O 12 , LiCoO2 and LiVO3; (2) The lithium-deficient adsorption material is a lithium-depleted lithium battery positive electrode material; Optionally, the lithium-free lithium battery positive electrode material includes FePO4, Li 1-x Mn2O4、Li 4-x Ti5O 12 , Li 1-x CoO2 and Li 1-x One or more of VO3; wherein 0<x<1.

9. The method for extracting lithium from salt lake according to claim 8, characterized in that: The solid contents of the lithium-rich adsorption material and the lithium-deficient adsorption material are independently 20 g / L to 100 g / L.

10. The method for extracting lithium from salt lake according to any one of claims 6 to 9, characterized in that: The voltages applied by the first power supply and the second power supply are independently 0.2V~1.0V.

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