An electrochemical lithium extraction system based on a cyclic regenerative flow electrode

Abstract

The application relates to the technical field of electrochemical lithium extraction, and specifically discloses an electrochemical lithium extraction system based on a circulating regenerated flow electrode, which comprises a lithium extraction unit and a flow electrode circulating regeneration unit, the lithium extraction unit comprises a lithium-lean flow electrode adsorption channel, a lithium-containing salt water channel, a recovery liquid channel and a lithium-rich flow electrode dissociation channel arranged in sequence, the flow electrode circulating regeneration unit comprises a circulating assembly used for driving the flow electrode to circulate between the lithium-lean flow electrode adsorption channel and the lithium-rich flow electrode dissociation channel, and further comprises a regeneration assembly arranged between a liquid outlet end of the lithium-lean flow electrode adsorption channel and a liquid inlet end of the lithium-rich flow electrode dissociation channel. The application helps to improve the problem that the mass transfer process of a cation exchange membrane is limited in the related art, so that the lithium extraction efficiency is improved; and the lithium extraction unit in the application is easy to integrate, and can realize the lithium extraction of a large amount of salt water.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrochemical lithium extraction, and particularly relates to an electrochemical lithium extraction system based on a circulating regeneration flow electrode. BACKGROUND

[0002] Lithium is widely used in energy storage batteries, glass ceramic manufacturing, chemical catalysis, nuclear industry and other fields due to its active properties. Lithium resources mainly exist in solid ores and salt water media such as salt lakes and seawater. The lithium ore reserves are limited, unevenly distributed, and the ore extraction technology has problems of high energy consumption and high pollution. The total amount of lithium resources in salt water is large, but the lithium concentration in salt water is low and the impurity ion concentration is high. How to develop an effective salt water lithium extraction technology has become a hot spot of attention.

[0003] Electrochemical lithium extraction is a lithium extraction technology based on the high selectivity of the lithium extraction electrode structure to lithium ions. An electrochemical lithium extraction device usually includes a lithium extraction electrode, an electrolyte solution and a counter electrode. The lithium extraction process is realized through three steps: 1) under the condition of discharging, lithium ions in a multi-ion salt water system are selectively embedded in positive active particles in the lithium extraction electrode; 2) after the lithium extraction electrode reaches the saturation capacity, the salt water electrolyte is pumped out, and the electrode is washed with fresh water to wash away the residual salt water; 3) the recovery liquid is pumped in as the electrolyte, and the embedded lithium ions can be released by charging. The electrochemical lithium extraction technology has the characteristics of high selectivity and low energy consumption.

[0004] At present, researchers have developed a solid-state electrode lithium extraction system taking lithium manganate, lithium iron phosphate and nickel-cobalt-manganese ternary materials as lithium extraction electrodes, and taking platinum, activated carbon, silver and polypyrrole as counter electrodes. However, the electrochemical lithium extraction process of the solid-state electrode still has the disadvantage of space-time discontinuity in the charging and discharging processes, which reduces the lithium extraction efficiency. Moreover, the system design is more complex due to the need to replace the fluid. The flushing process also consumes additional fresh water.

[0005] In order to improve the space-time discontinuity problem of the solid-state electrode lithium extraction, the electrochemical lithium extraction technology based on the flow electrode has been developed at present. Usually, the lithium extraction electrode is prepared into a fluid, and the flow electrode and the salt water are separated by a cation exchange membrane. Under the action of an electric field, lithium ions in the salt water penetrate the cation exchange membrane into the flow electrode, and the lithium ions are selectively embedded in the active particles. Subsequently, the lithium ions are released from the flow electrode through the electric desorption process.

[0006] However, due to the extremely low concentration of lithium ions and the extremely high concentration of impurity cations in the salt water, the competition between lithium ions and impurity cations limits the mass transfer process of lithium ions through the cation exchange membrane, resulting in a decrease in the mass transfer efficiency of lithium ions and affecting the lithium extraction efficiency. SUMMARY

[0007] In order to improve the problem that in the related art, the mass transfer process of the cation exchange membrane is limited in the environment with extremely high impurity cation concentration, resulting in low lithium extraction efficiency, an electrochemical lithium extraction system based on a circulating regenerated flow electrode is provided.

[0008] The electrochemical lithium extraction system based on the circulating regenerated flow electrode provided in the application adopts the following technical scheme:

[0009] The electrochemical lithium extraction system based on the circulating regenerated flow electrode comprises:

[0010] The lithium extraction unit comprises a lithium-lean flow electrode adsorption channel, a lithium-containing salt water channel, a recovery liquid channel and a lithium-rich flow electrode dissociation channel arranged in sequence; the lithium-lean flow electrode adsorption channel is used for filling a lithium-lean flow electrode, and the lithium-rich flow electrode dissociation channel is used for filling a lithium-rich flow electrode;

[0011] The flow electrode circulating regeneration unit comprises a circulating assembly used for driving the flow electrode to circulate between the lithium-lean flow electrode adsorption channel and the lithium-rich flow electrode dissociation channel, and further comprises a regeneration assembly arranged between a liquid outlet end of the lithium-lean flow electrode adsorption channel and a liquid inlet end of the lithium-rich flow electrode dissociation channel.

[0012] The regeneration assembly is used for regenerating the lithium-rich impurity-containing salt water flow electrode in the lithium-lean flow electrode adsorption channel into a lithium-rich pure flow electrode, and the regeneration assembly comprises a centrifugal device and a mixing device arranged in sequence along the flow direction of the flow electrode.

[0013] A diaphragm is arranged between the lithium-lean flow electrode adsorption channel and the lithium-containing salt water channel, between the recovery liquid channel and the lithium-rich flow electrode dissociation channel, and between the lithium-containing salt water channel and the recovery liquid channel.

[0014] An electric field is applied between the lithium-lean flow electrode adsorption channel and the lithium-rich flow electrode dissociation channel, lithium ions in the lithium-containing salt water channel pass through the diaphragm into the lithium-lean flow electrode adsorption channel under the action of the electric field, and in the lithium-lean flow electrode adsorption channel, the active lithium extraction particles in the lithium-lean flow electrode adsorb the lithium ions; in the lithium-rich flow electrode dissociation channel, the active lithium extraction particles in the lithium-rich flow electrode perform an electrochemical lithium deintercalation process, and the deintercalated lithium ions pass through the diaphragm into the recovery liquid, so that the lithium ions are enriched. The recovery liquid and the lithium-containing salt water exchange anions through the anion exchange membrane to maintain the electrical neutrality of the solution.

[0015] After the system is operated for a period of time, a lithium-rich flow electrode containing salt water impurities is formed in the lithium-lean flow electrode adsorption channel, and a lithium-lean flow electrode is formed in the lithium-rich flow electrode dissociation channel.

[0016] The lithium-poor flow electrode in the adsorption channel is driven to flow into the lithium-rich flow electrode dissociation channel by the circulation assembly, and the lithium-rich flow electrode in the dissociation channel is driven to flow into the lithium-poor flow electrode adsorption channel. In this process, the lithium-containing particles in the lithium-rich impurity-containing brine flow electrode are separated from the impurity brine by the centrifugal device, and the separated lithium-containing particles are mixed with the pure recovered liquid by the mixing device to regenerate the lithium-rich pure flow electrode, and then the lithium-rich pure flow electrode is supplemented into the lithium-rich flow electrode dissociation channel.

[0017] Since the mass transfer process of lithium ions in the present application does not depend on the cation exchange membrane, the mass transfer of lithium ions can maintain high efficiency in an environment with extremely high content of impurity cations, thereby helping to improve the lithium extraction efficiency. On the other hand, the use of a cation exchange membrane is also conducive to reducing costs, thereby facilitating the large-scale implementation of lithium extraction.

[0018] Further, the circulation assembly comprises a lithium-rich impurity-containing brine flow electrode storage tank, a lithium-rich pure flow electrode storage tank and a lithium-poor pure flow electrode storage tank;

[0019] The lithium-rich impurity-containing brine flow electrode storage tank, the centrifugal device, the mixing device, the lithium-rich pure flow electrode storage tank are sequentially connected between the outlet end of the lithium-poor flow electrode adsorption channel and the inlet end of the lithium-rich flow electrode dissociation channel along the flow direction of the flow electrode;

[0020] The lithium-poor pure flow electrode storage tank is connected between the inlet end of the lithium-poor flow electrode adsorption channel and the outlet end of the lithium-rich flow electrode dissociation channel.

[0021] Further, the inlet end of the centrifugal device is connected with the outlet end of the lithium-rich impurity-containing brine flow electrode storage tank, the solid outlet end of the centrifugal device is connected with the inlet end of the mixing device, and the outlet end of the mixing device is connected with the inlet end of the lithium-rich pure flow electrode storage tank.

[0022] Further, the centrifugal device is a centrifuge, and the mixing device is a stirring mixer.

[0023] Further, the recovered liquid channel is connected with a recovered liquid storage tank.

[0024] The lithium-rich impurity-containing brine flow electrode in the lithium-poor flow electrode adsorption channel is pumped into the centrifugal device to separate the lithium-containing particles from the impurity brine, the separated solid particles are sent into the mixing device to mix with the pure recovered liquid to obtain the lithium-rich pure flow electrode, and the lithium-rich pure flow electrode is pumped into the lithium-rich flow electrode dissociation channel to realize the regeneration and circulation of the lithium extraction electrode.

[0025] The present application also provides an electrochemical lithium extraction method based on the circulation and regeneration of flow electrodes, comprising the following steps:

[0026] 1) Preparation of full lithium pure flow electrode and lithium-poor pure flow electrode;

[0027] 2) Flow electrode pretreatment: Pump the full lithium pure flow electrode into the lithium-rich flow electrode dissociation channel as an anode, pump the lithium-poor pure flow electrode into the lithium-poor flow electrode adsorption channel as a cathode, pump the recovery liquid into the lithium-containing salt water channel and the recovery liquid channel as a supporting electrolyte, and apply an electric field between the lithium-poor flow electrode adsorption channel and the lithium-rich flow electrode dissociation channel;

[0028] 3) Lithium extraction process: Pump the lithium-poor pure flow electrode into the lithium-poor flow electrode adsorption channel, pump the lithium-containing salt water into the lithium-containing salt water channel, pump the recovery liquid into the recovery liquid channel, and pump the full lithium flow electrode into the lithium-rich flow electrode dissociation channel; apply an electric field between the lithium-poor flow electrode adsorption channel and the lithium-rich flow electrode dissociation channel;

[0029] 4) Flow electrode regeneration cycle process: Pump the flow electrode in the lithium-poor flow electrode adsorption channel into a centrifugal device to separate lithium-containing particles from impurity salt water, and send the obtained solid particles to a mixing device to mix with pure recovery liquid, regenerate the lithium-rich pure flow electrode, and pump it into the lithium-rich flow electrode dissociation channel.

[0030] Further, the raw materials for preparing the full lithium pure flow electrode include active lithium extraction particles, a conductive agent, and an electrolyte solution, and the raw materials for preparing the lithium-poor pure flow electrode include a conductive agent and an electrolyte solution.

[0031] Further, the active lithium extraction particles are selected from one or more of lithium iron phosphate, lithium manganate, nickel-cobalt-manganese ternary material, and nickel-manganese binary material.

[0032] Further, the conductive agent is selected from one or more of acetylene black, ketjen black, and carbon nanotube.

[0033] The application also provides an electrochemical lithium extraction device based on a cyclic regeneration flow electrode, which includes a plurality of lithium extraction units.

[0034] The plate-and-frame stacking is adopted to integrate the plurality of lithium extraction units, the processing capacity is amplified by simple number expansion, there is no amplification effect, and large-scale salt water lithium extraction is facilitated.

[0035] In summary, the application has at least one of the following beneficial technical effects:

[0036] 1. Since the mass transfer process of lithium ions in the application does not depend on the cation exchange membrane, the mass transfer of lithium ions can maintain high efficiency in an environment with a very high content of impurity cations, thereby helping to improve the lithium extraction efficiency; on the other hand, the use of a cation exchange membrane is also conducive to reducing costs, thereby facilitating the large-scale implementation of lithium extraction;

[0037] 2. The application can realize continuous lithium extraction by regenerating and recycling lithium extraction electrodes through centrifugal devices and mixing devices.

[0038] 3. The lithium extraction unit in the application has a simple structure, multiple lithium extraction units can be integrated by adopting a plate and frame type stacking, the processing capacity can be enlarged by simple number expansion, there is no amplification effect, and large-scale brine lithium extraction can be easily realized. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 is a structural schematic diagram of an electrochemical lithium extraction system based on a circulating regenerated flow electrode according to an embodiment of the application;

[0040] Figure 2 is a structural schematic diagram of an electrochemical lithium extraction system based on a circulating regenerated flow electrode according to an embodiment of the application;

[0041] Figure 3 is a voltage curve, lithium extraction current efficiency and energy consumption diagram under different current densities.

[0042] The drawings show that: 1 is a cathode current collector; 2 is a lithium-poor flow electrode adsorption channel; 3 is a first diaphragm; 4 is a lithium-containing brine channel; 5 is an anion exchange membrane; 6 is a recovery liquid channel; 7 is a second diaphragm; 8 is a lithium-rich flow electrode dissociation channel; 9 is an anode current collector; 10 is a lithium-rich impurity-containing brine flow electrode storage tank; 11 is a centrifuge; 12 is a stirring mixer; 13 is a lithium-rich pure flow electrode storage tank; 14 is a lithium-poor pure flow electrode storage tank; 15 is a recovery liquid storage tank. DETAILED DESCRIPTION

[0043] The drawings will be described below Figures 1-3 The application will be further described in detail.

[0044] Example 1

[0045] The embodiment of the application discloses an electrochemical lithium extraction system based on a circulating regenerated flow electrode, which comprises a lithium extraction unit and a flow electrode circulating regeneration unit.

[0046] Referring to Figure 1 , the lithium extraction unit comprises a lithium-poor flow electrode adsorption channel 2, a lithium-containing brine channel 4, a recovery liquid channel 6 and a lithium-rich flow electrode dissociation channel 8 arranged in sequence; the lithium-poor flow electrode adsorption channel 2 is used to fill a lithium-poor flow electrode, and the lithium-rich flow electrode dissociation channel 8 is used to fill a lithium-rich flow electrode. The cathode current collector 1 is arranged on one side of the lithium-poor flow electrode adsorption channel 2, and the anode current collector 9 is arranged on one side of the lithium-rich flow electrode dissociation channel 8. The side walls of each channel are made of plastic partitions, and flow channels are engraved on the inner sides of the partitions.

[0047] Referring to Figure 1, a first diaphragm 3 is arranged between the lithium-poor flow electrode adsorption channel 2 and the lithium-containing salt water channel 4, and a second diaphragm 7 is arranged between the recovery liquid channel 6 and the lithium-rich flow electrode dissociation channel 8, and an anion exchange membrane 5 is arranged between the lithium-containing salt water channel 4 and the recovery liquid channel 6.

[0048] The first diaphragm 3 and the second diaphragm 7 are both porous membranes, which are used to intercept carbon particle clusters (a few hundred nanometers) and active lithium extraction material particles (a few hundred nanometers to microns) in the flow electrode; at the same time, the first diaphragm 3 and the second diaphragm 7 both allow ions and water molecules to freely pass through.

[0049] Referring to Figure 1 , the flow electrode cyclic regeneration unit comprises a circulation assembly for driving the flow electrode to circulate between the lithium-poor flow electrode adsorption channel 2 and the lithium-rich flow electrode dissociation channel 8, and further comprises a regeneration assembly arranged between the liquid outlet end of the lithium-poor flow electrode adsorption channel 2 and the liquid inlet end of the lithium-rich flow electrode dissociation channel 8, which is used to regenerate the lithium-rich flow electrode with impure salt water in the lithium-poor flow electrode adsorption channel 2 into a lithium-rich pure flow electrode.

[0050] Specifically, referring to Figure 1 , the circulation assembly comprises a lithium-rich flow electrode with impure salt water storage tank 10, a lithium-rich pure flow electrode storage tank 13, a lithium-poor pure flow electrode storage tank 14, a plurality of pipelines and pumps (not shown in the figure) installed on the pipelines; and the regeneration assembly comprises a centrifuge 11 and a stirring mixer 12.

[0051] Referring to Figure 1 , the lithium-rich flow electrode with impure salt water storage tank 10, the centrifuge 11, the stirring mixer 12 and the lithium-rich pure flow electrode storage tank 13 are sequentially connected between the liquid outlet end of the lithium-poor flow electrode adsorption channel 2 and the liquid inlet end of the lithium-rich flow electrode dissociation channel 8 in the flow direction of the flow electrode. The solid discharge end of the centrifuge 11 is communicated with the feeding end of the stirring mixer 12.

[0052] Further, referring to Figure 1 , the lithium-poor pure flow electrode storage tank 14 is connected between the liquid inlet end of the lithium-poor flow electrode adsorption channel 2 and the liquid outlet end of the lithium-rich flow electrode dissociation channel 8. The recovery liquid channel 6 is connected with a recovery liquid storage tank 15 for storing recovery liquid, and the recovery liquid can circulate between the recovery liquid channel 6 and the recovery liquid storage tank 15.

[0053] When lithium is extracted, an electric field is applied between the cathode current collector 1 and the anode current collector 9, and lithium ions in the lithium-containing salt water channel 4 pass through the first diaphragm 3 into the lithium-poor flow electrode adsorption channel 2 under the action of the electric field. In the lithium-poor flow electrode adsorption channel 2, lithium ions are embedded in the active lithium extraction particles in the lithium-poor flow electrode.

[0054] In the lithium-rich flow electrode dissociation channel 8, the active lithium extraction particles in the lithium-rich flow electrode are in contact with the conductive agent network or the current collector and charge transfer occurs, and lithium ions are deintercalated from the active lithium extraction particles. The deintercalated lithium ions pass through the second separator 7 into the recovery liquid channel 6 under the action of an electric field, realizing the enrichment of lithium ions. In this process, the recovery liquid exchanges anions with the lithium-containing salt water through the anion exchange membrane 5 to maintain the solution electrically neutral.

[0055] After the system runs for a period of time, a lithium-rich flow electrode containing impure salt water is formed in the lithium-lean flow electrode adsorption channel 2, and a lithium-lean flow electrode is formed in the lithium-rich flow electrode dissociation channel 8.

[0056] The lithium-rich flow electrode in the lithium-lean flow electrode adsorption channel 2 is pumped to the lithium-rich flow electrode dissociation channel 8. In this process, the lithium-containing particles in the lithium-rich flow electrode are separated from the impure salt water by the centrifuge 11, and the separated lithium-containing particles are mixed with pure recovery liquid by the stirring mixer 12, and a lithium-rich pure flow electrode is regenerated, and then the lithium-rich pure flow electrode is continuously supplemented to the lithium-rich flow electrode dissociation channel 8.

[0057] At the same time, the lithium-lean flow electrode in the lithium-rich flow electrode dissociation channel 8 is pumped to the lithium-lean flow electrode adsorption channel 2, realizing the circulation of the flow electrode outside.

[0058] Since the mass transfer process of lithium ions in the present application does not depend on the cation exchange membrane, the mass transfer of lithium ions can maintain high efficiency in an environment with a very high content of impurity cations, thereby helping to improve the lithium extraction efficiency. On the other hand, the use of a cation exchange membrane is also conducive to reducing costs, thereby facilitating the large-scale implementation of lithium extraction.

[0059] Example 2

[0060] The embodiments of the present application disclose an electrochemical lithium extraction device based on a circulating and regenerative flow electrode. Referring to Figure 2 , the electrochemical lithium extraction device based on a circulating and regenerative flow electrode comprises a plurality of lithium extraction units; the plurality of lithium extraction units are arranged in parallel and stacked in a plate-and-frame manner. The plurality of lithium extraction units can share a set of flow electrode circulating and regenerative units, or multiple sets of flow electrode circulating and regenerative units can be used as needed. The specifications of the centrifuge 11 and the stirring mixer 12 and the volumes of the respective storage tanks can be selected according to the needs of the lithium extraction scale.

[0061] In this way, the plurality of lithium extraction units can be integrated, the processing capacity can be amplified by simple quantity expansion, there is no amplification effect, and large-scale salt water lithium extraction can be easily realized.

[0062] Example 3

[0063] The embodiments of the present application disclose an electrochemical lithium extraction method based on a circulating and regenerative flow electrode, comprising the following steps:

[0064] 1) Preparation of full lithium pure stream electrode and poor lithium pure stream electrode:

[0065] Take lithium manganate as active lithium extraction particles, take acetylene black as conductive agent, and take lithium salt water or monovalent ion electrolyte solution without divalent ion as electrolyte solution. In this embodiment, 100 mM KCl solution is taken as electrolyte solution.

[0066] The active lithium extraction particles and the conductive agent particles are uniformly ground and mixed, and then the electrolyte solution is added and stirred overnight to obtain the full lithium pure stream electrode. The mass fraction of the active lithium extraction particles is more than 5 wt%, and the mass fraction of the conductive agent is 2 wt%-4 wt%.

[0067] The conductive agent particles are added to the electrolyte solution and stirred overnight to obtain the poor lithium pure stream electrode. The mass fraction of the conductive agent is 2 wt%-4 wt%.

[0068] 2) Stream electrode pretreatment:

[0069] The full lithium pure stream electrode is pumped into the lithium-rich stream electrode dissociation channel 8 as an anode, and the poor lithium pure stream electrode is pumped into the poor lithium stream electrode adsorption channel 2 as a cathode.

[0070] 100 mM KCl solution is taken as recovery liquid, the recovery liquid is pumped into the lithium salt water channel 4 and the recovery liquid channel 6 as supporting electrolyte, an electric field is applied between the anode current collector 9 and the cathode current collector 1, the pretreatment current is 0.5 mA / cm 2 ; lithium ions are extracted from the full lithium pure stream electrode of the anode, and after 10 h of treatment, a poor lithium pure stream electrode is obtained to start the system cycle.

[0071] 3) Lithium extraction process:

[0072] The poor lithium pure stream electrode is pumped into the poor lithium stream electrode adsorption channel 2, the lithium salt water is pumped into the lithium salt water channel 4, the lithium salt water is simulated salt lake water, the recovery liquid is pumped into the recovery liquid channel 6, and the full lithium stream electrode is pumped into the lithium-rich stream electrode dissociation channel 8; an electric field is applied between the anode current collector 9 and the cathode current collector 1.

[0073] 4) Stream electrode regeneration cycle process: the stream electrode in the poor lithium stream electrode adsorption channel 2 is pumped into a centrifuge 11 to separate the lithium-containing particles from the impurity salt water, the separated solid particles are sent into a stirring mixer 12 and mixed with pure recovery liquid, a lithium-rich pure stream electrode is regenerated and pumped into the lithium-rich stream electrode dissociation channel 8; at the same time, the stream electrode in the lithium-rich stream electrode dissociation channel 8 is pumped into the poor lithium stream electrode adsorption channel 2.

[0074] The system was cycled for two cycles with a flow rate of 10 mL / min in each of the four flow channels. In the first cycle, lithium ions in the salt solution were intercalated into the lithium-depleted flow electrode, and after the end of the cycle, the flow electrode was purified by centrifugation and the intercalated lithium ions were dissociated in the second cycle. The voltage curves, lithium extraction current efficiency and energy consumption at different current densities (0.3 mA / cm 2 , 0.6 mA / cm 2 , 0.9 mA / cm 2 , 1.2 mA / cm 2 ) in the second cycle are shown in Figure 3 .

[0075] As can be seen from Figure 3 b, when the current density is 0.3 mA / cm 2 , 0.9 mA / cm 2 and 1.2 mA / cm 2 , the current efficiency can reach more than 90%. As can be seen from Figure 3 c, when the current density is 0.3 mA / cm 2 , 0.6 mA / cm 2 and 0.9 mA / cm 2 , the energy consumption is relatively low.

[0076] The above are preferred embodiments of the present application, and are not intended to limit the protection scope of the present application, therefore: any equivalent changes made according to the structure, shape, principle of the present application should be covered within the protection scope of the present application.

Claims

1. An electrochemical lithium extraction system based on a circulating regeneration current electrode, characterized in that: include: The lithium extraction unit includes a lithium-poor flow electrode adsorption channel, a lithium-containing brine channel, a recovery liquid channel, and a lithium-rich flow electrode dissociation channel arranged in sequence; the lithium-poor flow electrode adsorption channel is used to fill the lithium-poor flow electrode, and the lithium-rich flow electrode dissociation channel is used to fill the lithium flow electrode. The flow electrode circulation and regeneration unit includes a circulation component for driving the flow electrode to circulate between the lithium-poor flow electrode adsorption channel and the lithium-rich flow electrode dissociation channel, and also includes a regeneration component disposed between the liquid outlet end of the lithium-poor flow electrode adsorption channel and the liquid inlet end of the lithium-rich flow electrode dissociation channel. The regeneration assembly is used to regenerate the lithium-rich, impurity-containing saline flow electrode in the lithium-poor flow electrode adsorption channel into a lithium-rich, pure flow electrode. The regeneration assembly includes a centrifugal device and a mixing device arranged sequentially along the flow direction of the flow electrode. A diaphragm is provided between the lithium-poor flow electrode adsorption channel and the lithium-containing brine channel, and between the recovery liquid channel and the lithium-rich flow electrode dissociation channel. An anion exchange membrane is provided between the lithium-containing brine channel and the recovery liquid channel. The membrane is a porous membrane used to trap carbon particle clusters and active lithium extraction material particles in the flow electrode, while allowing ions and water molecules to pass through.

2. The electrochemical lithium extraction system based on a circulating regeneration current electrode according to claim 1, characterized in that: The circulation assembly includes a lithium-rich brine electrode storage tank containing impurities, a lithium-rich pure electrode storage tank, and a lithium-poor pure electrode storage tank. The lithium-rich saline electrode storage tank containing impurities, the centrifuge device, the mixing device, and the lithium-rich pure electrode storage tank are sequentially connected along the flow direction of the electrode between the liquid outlet end of the lithium-poor electrode adsorption channel and the liquid inlet end of the lithium-rich electrode dissociation channel. The lithium-poor pure flow electrode storage tank is connected between the liquid inlet end of the lithium-poor flow electrode adsorption channel and the liquid outlet end of the lithium-rich flow electrode dissociation channel.

3. The electrochemical lithium extraction system based on a circulating regeneration flow electrode according to claim 2, characterized in that: The feed end of the centrifuge device is connected to the liquid outlet of the lithium-rich, impurity-containing saline electrode storage tank, the solid discharge end of the centrifuge device is connected to the feed end of the mixing device, and the discharge end of the mixing device is connected to the liquid inlet of the lithium-rich, pure electrode storage tank.

4. The electrochemical lithium extraction system based on a circulating regeneration current electrode according to claim 3, characterized in that: The centrifugal device is a centrifuge, and the mixing device is a stirrer.

5. The electrochemical lithium extraction system based on a circulating regeneration flow electrode according to claim 1, characterized in that: The recovery liquid channel is connected to a recovery liquid storage tank.

6. An electrochemical lithium extraction method based on a circulating regenerated current electrode, characterized in that: The electrochemical lithium extraction system based on a circulating regeneration flow electrode as described in any one of claims 1-5 includes the following steps: 1) Prepare lithium-rich pure flow electrodes and lithium-poor pure flow electrodes; 2) Pretreatment of the flow electrode: The full lithium pure flow electrode is pumped into the lithium rich flow electrode dissociation channel as the anode, and the lithium poor pure flow electrode is pumped into the lithium poor flow electrode adsorption channel as the cathode. The recovered liquid is pumped into the lithium brine channel and the recovered liquid channel as the supporting electrolyte. An electric field is applied between the lithium poor flow electrode adsorption channel and the lithium rich flow electrode dissociation channel. 3) Lithium extraction process: A lithium-poor pure flow electrode is pumped into the lithium-poor flow electrode adsorption channel, a lithium-containing brine is pumped into the lithium-containing brine channel, a recovery liquid is pumped into the recovery liquid channel, and a full lithium flow electrode is pumped into the lithium-rich flow electrode dissociation channel; an electric field is applied between the lithium-poor flow electrode adsorption channel and the lithium-rich flow electrode dissociation channel; lithium ions in the lithium-containing brine channel pass through the membrane into the lithium-poor flow electrode adsorption channel under the action of the electric field, and in the lithium-poor flow electrode adsorption channel, lithium ions are embedded into the active lithium extraction particles in the lithium-poor flow electrode; in the lithium-rich flow electrode dissociation channel, lithium ions in the full lithium flow electrode are de-intercalated from the active lithium extraction particles, and the de-intercalated lithium ions pass through the membrane into the recovery liquid channel under the action of the electric field; 4) Flow electrode regeneration cycle process: The flow electrode in the lithium-poor flow electrode adsorption channel is pumped into a centrifuge to separate lithium-containing particles from impurity brine. The separated solid particles are sent to a mixing device to mix with pure recovery liquid, and regenerated to obtain a lithium-rich pure flow electrode, which is then pumped into the lithium-rich flow electrode dissociation channel.

7. The electrochemical lithium extraction method based on a circulating regeneration current electrode according to claim 6, characterized in that: The raw materials for preparing the full-lithium pure flow electrode include active lithium extraction particles, a conductive agent, and an electrolyte solution; the raw materials for preparing the lithium-poor pure flow electrode include a conductive agent and an electrolyte solution.

8. The electrochemical lithium extraction method based on a circulating regeneration current electrode according to claim 7, characterized in that: The active lithium extraction particles are selected from one or more of lithium iron phosphate, lithium manganese oxide, nickel-cobalt-manganese ternary materials, and nickel-manganese binary materials.

9. The electrochemical lithium extraction method based on a circulating regeneration current electrode according to claim 7, characterized in that: The conductive agent is selected from one or more of acetylene black, Ketjen black, and carbon nanotubes.

10. An electrochemical lithium extraction device based on a circulating regeneration current electrode, characterized in that: Includes the lithium extraction unit as described in any one of claims 1-5.

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