Electrode-intercalation lithium extraction system based on parameter decoupling to improve robustness and application thereof

Abstract

The application provides an electric deintercalation lithium extraction system and belongs to the technical field of lithium extraction from salt lakes.The electric deintercalation lithium extraction system comprises an electric deintercalation membrane stack, the electric deintercalation membrane stack comprises at least one membrane stack unit, and the membrane stack unit comprises a lithium extraction electrode plate; and parameters in the electric deintercalation lithium extraction process satisfy formula (1): D=. The application can accurately estimate electric deintercalation lithium extraction related parameters through a mathematical model, is favorable for accurately controlling the values of various parameters in the electric deintercalation lithium extraction process, ensures that the production capacity of lithium extraction equipment is fully utilized, and improves production efficiency. The robustness of the mathematical estimation model of the application can be improved through the adjustment of the balance coefficient D of the electric deintercalation lithium extraction system.

Description

Technical Field

[0001] This invention belongs to the field of lithium extraction technology from salt lakes, specifically relating to an electro-extraction and intercalation lithium extraction system based on parameter decoupling to improve robustness and its application. Background Technology

[0002] In recent years, with the rapid development of new energy vehicles and energy storage industries, the demand for lithium has surged. Lithium carbonate, as a key lithium salt, is widely used in the new energy vehicle sector. Currently, lithium carbonate mainly comes from lithium extraction from ore and lithium extraction from salt lakes. Compared to lithium extraction from ore, the lithium reserves in salt lake brines are enormous (accounting for 65% of global reserves). Lithium extraction from salt lakes not only reduces reagent consumption during mineral leaching but also has a cost advantage, making it a major direction for lithium salt production.

[0003] Magnesium-lithium separation is a major technical challenge in lithium extraction from salt lakes. China has the world's third-largest lithium reserves (80% of which are found in salt lake brines), but much of this brines have a high magnesium-to-lithium ratio, making efficient development difficult. To address this challenge, researchers have developed various processing technologies, such as adsorption, electrodialysis, nanofiltration, and extraction. In recent years, a new lithium extraction method based on the "rocking chair" lithium-ion battery principle—electrochemical deintercalation—has been proposed. This technology uses lithium-rich lithium-ion battery materials as the anode and lithium-deficient lithium-ion battery materials as the cathode, constructing a new electrochemical deintercalation system for lithium extraction from salt lakes: "lithium-rich electrode-electrolyte-anion exchange membrane-brine-lithium-deficient electrode."

[0004] For actual production, the lithium extraction rate directly affects production efficiency and cost. Fully utilizing the actual lithium extraction capacity of the electro-deintercalation lithium extraction equipment is beneficial for reducing industrial production costs and achieving energy conservation and emission reduction. In the electro-deintercalation lithium extraction process, key factors affecting the lithium extraction efficiency of the electrode plate include the coating quality of the electrode plate material surface and the lithium ion concentration in the brine (Li). + The concentration level of lithium, the set value of the cell voltage, and the temperature conditions of the brine during operation are all important factors. Precisely adjusting and balancing the interactions between these parameters to optimize the efficiency of lithium electro-extraction and extraction, and to improve the overall efficiency of lithium extraction from salt lakes, is of great significance.

[0005] Specifically, increasing the brine flow rate in the lithium extraction cycle can improve lithium extraction efficiency to some extent. However, blindly increasing the brine flow rate may damage the coating material on the electrode surface, affecting cycle performance and reducing the service life of components such as the anion exchange membrane. Therefore, scientifically evaluating the balance relationship of various parameters in the electro-extraction and insertion lithium extraction process is beneficial for accurately controlling the values ​​of each parameter during the process, ensuring full utilization of the lithium extraction equipment's capacity, improving production efficiency, and reducing operating costs.

[0006] Therefore, this invention is proposed. Summary of the Invention

[0007] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes an electro-extraction and intercalation lithium extraction system and its application based on parameter decoupling to improve robustness. The system aims to precisely control various factors in the electro-extraction and intercalation lithium extraction process to ensure the efficient operation of the lithium extraction process in salt lakes.

[0008] According to a first aspect of the present invention, an electro-deintercalation lithium extraction system is provided, comprising an electro-deintercalation membrane stack, the electro-deintercalation membrane stack comprising at least one membrane stack unit, the membrane stack unit comprising a lithium extraction electrode plate; The parameters in the electro-deintercalation and extraction of lithium satisfy the following equation (1): D = Equation (1); in, D is the balance coefficient of the electro-deintercalation lithium extraction system, and its value ranges from D∈[0.95,1.05]. Q represents the brine flow rate, in L / h; This represents the lithium ion concentration in the brine, expressed in g / L. S represents the area of ​​the lithium extraction electrode, in m². 2 ; k1 is the efficiency coefficient of the brine in providing lithium ions per unit electrode area, and its value is 1 / m. 2 ; B is the lithium extraction frequency factor, taken as an empirical value of 5.72 × 10⁻⁶. 3 cm 2 / (V·min); The voltage applied during the electro-deintercalation / extraction of lithium, with a range of values. ∈[0.35,1.1]V; The density of the iron phosphate coating on the lithium electrode surface is measured in mg / cm³. 2 ; E is the apparent activation energy, which is 18.9 kJ / mol; R is the molar gas constant, with a value of 8.314 J / (mol·K); T represents the brine temperature during the electro-deintercalation and extraction of lithium, in K. N is the number of membrane stack units; The correction parameters satisfy the following formula: , The attenuation coefficient is set to 0.01h. -1 ; t is the time for lithium extraction and deintercalation, t∈[0,24]h.

[0009] denominator This is an estimated formula for the lithium extraction capacity per unit time of an electro-extraction lithium extraction system, obtained by optimizing the electro-extraction lithium extraction kinetic equation. (Molecular...) The amount of lithium ions that the brine can provide per unit time on the lithium extraction plate was calculated; theoretically When the lithium extraction rate is 1, the lithium extraction rate of the lithium extraction plate matches the lithium ion rate provided by the brine, and the parameters of the electro-deintercalation lithium extraction system reach equilibrium. However, because the actual lithium extraction capacity of the lithium extraction plate will be lower than the theoretical calculation value, and it is impossible to completely separate all lithium ions from the brine during the actual lithium extraction process, therefore... The calculated system balance coefficient is too high, so parameter C is further adjusted. T The above equation is then corrected. Simultaneously, as the lithium extraction process progresses, the lithium extraction capability of the lithium extraction electrode gradually decreases; therefore, the correction parameter C... T It is a time-related variable, taking an empirical value. t represents the lithium extraction / deintercalation time.

[0010] Preferably, the electro-deintercalation lithium extraction system further includes a brine storage tank, a lithium-rich liquid storage tank, control valves, a liquid pumping device, and a control system, wherein the control system adjusts the brine flow rate according to the correction parameters. Further, the control system adjusts the brine flow rate according to the lithium ion concentration in the brine and the correction parameters.

[0011] Preferably, the brine flow rate is 3.32 × 10⁻⁶. 3 ~1.82×10 4 L / h.

[0012] Preferably, the area of ​​the electrode plate is 0.1~5m². 2 .

[0013] Preferably, the coating density ≤5000 mg / cm 2 .

[0014] Preferably, the brine temperature is 20~45℃. When calculating, the brine temperature is expressed in K, where K = ℃ + 273.15.

[0015] Preferably, the brine storage tank is equipped with a first temperature control device, and the lithium-rich liquid storage tank is equipped with a second temperature control device. The brine storage tank and the lithium-rich liquid storage tank in this invention are equipped with temperature control devices (such as electric heating, circulating water cooling, heat exchangers, etc.) to control the temperature of the brine and the lithium-rich liquid.

[0016] Preferably, the membrane stack unit includes a first separator, a first electrode plate, a second separator, an anion exchange membrane, a third separator, a second electrode plate, and a fourth separator arranged sequentially; the first separator and the second separator form a first chamber, and the third separator and the fourth separator form a second chamber. It is understood that the first electrode plate is located within the first chamber, and the second electrode plate is located within the second chamber. Optionally, the first separator, the first electrode plate, the second separator, the third separator, the second electrode plate, and the fourth separator are provided with an outer frame, and at least one end of the outer frame is provided with a through hole, allowing anions (such as chloride ions) in the brine within the membrane stack unit to pass through the anion exchange membrane into the lithium-rich solution during the electro-deintercalation and extraction of lithium, ensuring the continuous progress of the reaction; it also allows the charge balance of the electro-deintercalation and extraction system to be maintained between the membrane stack units through the anion exchange membrane.

[0017] Preferably, adjacent membrane stack units are separated by an additional anion exchange membrane.

[0018] More preferably, the electro-deintercalation / deintercalation membrane stack comprises multiple membrane stack units, wherein the first chambers of the multiple membrane stack units are sequentially connected by pipes, and the second chambers of the multiple membrane stack units are sequentially connected by pipes; and / or, the number of membrane stack units is 2 to 24. In this invention, "multiple" refers to two or more. The sequential connection of the first (second) chambers of the multiple membrane stack units by pipes means that the first (second) chamber of the first membrane stack unit is connected to the first (second) chamber of the second membrane stack unit. If a third membrane stack unit exists, its first (second) chamber is connected to the first (second) chamber of the second membrane stack unit, and so on. This connection method ensures that the flow rate of brine or lithium-rich solution is equal in each chamber, thereby stably controlling the electro-deintercalation / deintercalation lithium extraction process.

[0019] Preferably, the control valves include a lithium-rich liquid delivery valve and a brine delivery valve; the lithium-rich liquid delivery valve includes a first valve, a third valve, a fifth valve, and an eighth valve; the brine delivery valve includes a second valve, a fourth valve, a sixth valve, and a seventh valve; and the liquid pumping device includes a first liquid pump and a second liquid pump.

[0020] Preferably, in one operating state of the electro-deintercalation lithium extraction system, the third, fourth, fifth, and sixth valves are closed, while the first, second, seventh, and eighth valves are open. The solution in the lithium-rich liquid storage tank sequentially enters the electro-deintercalation membrane stack through the first valve and the first liquid pump, then sequentially passes through the second chamber in each membrane stack unit, and finally returns to the lithium-rich liquid storage tank via the eighth valve. Similarly, the solution in the brine storage tank sequentially enters the electro-deintercalation membrane stack through the second valve and the second liquid pump, then sequentially passes through the first chamber in each membrane stack unit, and finally returns to the brine storage tank via the seventh valve. In another operating state of the electro-deintercalation lithium extraction system, the third, fourth, fifth, and sixth valves are open, while the first, second, seventh, and eighth valves are closed. The solution in the lithium-rich liquid storage tank enters the electro-deintercalation membrane stack sequentially through the third valve and the second liquid pump, then passes through the first chamber in each membrane stack unit, and finally returns to the lithium-rich liquid storage tank via the fifth valve. Similarly, the solution in the brine storage tank enters the electro-deintercalation membrane stack sequentially through the fourth valve and the first liquid pump, then passes through the second chamber in each membrane stack unit, and finally returns to the brine storage tank via the sixth valve.

[0021] According to a second aspect of the present invention, the application of the electro-deintercalation lithium extraction system described in the first aspect of the present invention in lithium extraction production from salt lakes is proposed.

[0022] According to one embodiment of the present invention, at least the following beneficial effects are achieved: This invention proposes an electro-extraction / intercalation lithium extraction system based on parameter decoupling to improve robustness. By accurately estimating relevant parameters through a mathematical model, it facilitates precise control of the parameters during the extraction process, ensuring full utilization of the lithium extraction equipment's capacity and improving production efficiency. Adjusting the balance coefficient D of the electro-extraction / intercalation lithium extraction system enhances the robustness of the mathematical estimation model, adapting it to the needs of different models and specifications of lithium extraction equipment. Attached Figure Description

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 This is a physical structure diagram of the lithium electro-extraction and extraction system of the present invention; Figure 2 A schematic diagram illustrating the principle of lithium extraction via electro-deintercalation. Figure 3 This is a schematic diagram of a membrane stack structure; Figure 4 This is a trend chart of lithium extraction efficiency data for Embodiment 1 and Comparative Examples 1-2 of the present invention; Figure 5 This is a trend chart of lithium extraction efficiency data for Embodiment 2 and Comparative Examples 3-4 of the present invention; Figure 6 This is a trend chart of lithium extraction efficiency data for Embodiment 3 and Comparative Examples 5-6 of the present invention; Figure 7 This is a trend chart of lithium extraction efficiency data for Embodiment 4 and Comparative Examples 7-8 of the present invention; Figure 8 This is a trend chart of lithium extraction efficiency data for Embodiment 5 and Comparative Examples 9-10 of the present invention.

[0024] Figure label: 101. Electrodeintercalation / deintercalation stack; 201. Lithium-rich liquid storage tank; 301. Brine storage tank; 401. First liquid pump; 402. Second liquid pump; 501. First valve; 502. Second valve; 503. Third valve; 504. Fourth valve; 505. Fifth valve; 506. Sixth valve; 507. Seventh valve; 508. Eighth valve; 601, First end plate; 602, First rubber pad; 603, First membrane stack unit; 6031, First separator; 6032, First electrode plate; 6033, Second separator; 6034, First anion exchange membrane; 6035, Third separator; 6036, Second electrode plate; 6037, Fourth separator; 604, Second anion exchange membrane; 605, Second membrane stack unit; 606, Second rubber pad; 607, Second end plate. Detailed Implementation

[0025] The following will describe the concept and technical effects of the present invention clearly and completely with reference to the embodiments, so as to fully understand the purpose, features and effects of the present invention.

[0026] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. The terminology of this invention has its conventional meaning as understood by those skilled in the art (unless specifically stated otherwise).

[0027] The "range" disclosed in this invention is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the specific range. Specifically, "()", ")", "[", and "]" represent intervals, where "()" or ")" represents an open interval, meaning the endpoint values ​​of the interval are not included; and "[" and "]" represent a closed interval, meaning the endpoints of the interval are included. A range defined in this way can include endpoint values ​​or not, and can be arbitrarily combined, meaning any lower limit can be combined with any upper limit to form a range.

[0028] This invention proposes an electro-deintercalation lithium extraction system, comprising: an electro-deintercalation / deintercalation membrane stack 101, a brine storage tank 301, a lithium-rich liquid storage tank 201, control valves, a liquid pumping device, and a control system. The control valves include lithium-rich liquid delivery valves and brine delivery valves. The lithium-rich liquid delivery valves include a first valve 501, a third valve 503, a fifth valve 505, and an eighth valve 508. The brine delivery valves include a second valve 502, a fourth valve 504, a sixth valve 506, and a seventh valve 507. The liquid pumping device includes a first liquid pump 401 and a second liquid pump 402, as shown below. Figure 1 As shown.

[0029] In some embodiments, the brine storage tank and the lithium-rich liquid storage tank are each equipped with a temperature control device to control the temperature of the brine and the lithium-rich liquid. The temperature control device can be selected from one of electric heating, circulating water cooling, or a heat exchanger.

[0030] In some embodiments, the electro-deintercalation / deintercalation membrane stack 101 includes multiple membrane stack units. Each membrane stack unit includes a first separator 6031, a first electrode plate 6032, a second separator 6033, a first anion exchange membrane 6034, a third separator 6035, a second electrode plate 6036, and a fourth separator 6037 arranged sequentially. Adjacent membrane stack units are separated by an additionally provided second anion exchange membrane 604. The first separator 6031 and the second separator 6033 form a first chamber of the membrane stack unit, with the first electrode plate 6032 located within the first chamber. The third separator 6035 and the fourth separator 6037 form a second chamber of the membrane stack unit, with the second electrode plate 6036 located within the second chamber. The first separator, the first electrode plate, the second separator, the third separator, the second electrode plate, and the fourth separator are provided with an outer frame (not shown in the figure). One end of the outer frame is provided with a through hole, which allows anions (such as chloride ions) in the brine in the membrane stack unit to pass through the anion membrane into the lithium-rich solution during the electro-deintercalation and extraction of lithium, ensuring the continuous progress of the reaction; at the same time, the membrane stack units are maintained in stable operation of the electro-deintercalation and extraction of lithium system through the setting of anion membrane.

[0031] In some embodiments, the electro-deintercalation / deintercalation membrane stack 101 further includes a pair of end plates and a pair of rubber pads. Taking a stack of two membrane units as an example, the electro-deintercalation / deintercalation membrane stack 101 includes a first end plate 601, a first rubber pad 602, a first membrane unit 603, a second anion exchange membrane 604, a second membrane unit 605, a second rubber pad 606, and a second end plate 607 arranged sequentially. Figure 3 As shown.

[0032] When the electro-deintercalation lithium extraction system enters one of its operating states, the first electrode plate in the membrane stack unit is a cathode plate, and its surface can be coated with iron phosphate material; the second electrode plate is an anode plate, and its surface can be coated with lithium iron phosphate material; the third valve 503, the fourth valve 504, the fifth valve 505, and the sixth valve 506 are closed, while the first valve 501, the second valve 502, the seventh valve 507, and the eighth valve 508 are open. Brine in the brine storage tank 301 is pumped into the electro-deintercalation membrane stack 101 by the second liquid pump 402 through the second valve 502. The first chamber of the first membrane stack unit 603 and the first chamber of the second membrane stack unit 605 are connected by a pipe. The brine passes through the first chambers of multiple membrane stack units sequentially, and the iron ions in the first electrode plate gain electrons and are reduced, thereby allowing lithium ions in the brine to intercalate into iron phosphate to generate lithium iron phosphate. After leaving the electro-deintercalation membrane stack 101, the brine returns to the brine storage tank 301 via the seventh valve 507; the lithium-rich liquid storage tank 2... The lithium-rich liquid in 01 is pumped into the electro-deintercalation membrane stack 101 by the first liquid pump 401 through the first valve 501. The second chamber of the first membrane stack unit 603 and the second chamber of the second membrane stack unit 605 are connected by a pipe. The lithium-rich liquid passes through the second chambers of multiple membrane stack units in sequence. The ferrous ions in the second electrode plate lose electrons and are oxidized, causing the lithium ions in the lithium iron phosphate to be released to generate iron phosphate. The lithium ions enter the lithium-rich liquid to achieve enrichment. After leaving the electro-deintercalation membrane stack 101, the lithium-rich liquid returns to the lithium-rich liquid storage tank 201 through the eighth valve 508.

[0033] When the lithium extraction and deintercalation system enters another working state, the voltage applied to the electrode plate is opposite to that in the first working state. The first electrode plate of the membrane stack unit is the anode plate with a lithium iron phosphate material on its surface, and the second electrode plate is the cathode plate with an iron phosphate material on its surface. The third valve 503, the fourth valve 504, the fifth valve 505, and the sixth valve 506 are open, while the first valve 501, the second valve 502, the seventh valve 507, and the eighth valve 508 are closed. The brine in the brine storage tank 301 is pumped into the electro-deintercalation / deintercalation membrane stack 101 by the first liquid pump 401 through the fourth valve 504. The brine passes through the second chamber of multiple membrane stack units in sequence. The iron ions in the second electrode plate gain electrons and are reduced, which allows the lithium ions in the brine to intercalate into iron phosphate to form lithium iron phosphate. After leaving the electro-deintercalation / deintercalation membrane stack 101, the brine returns to the brine storage tank 301 through the sixth valve 506. The lithium-rich liquid in the lithium-rich liquid storage tank 201 is pumped into the electro-deintercalation / deintercalation membrane stack 101 by the second liquid pump 402 through the third valve 503. The lithium-rich liquid passes through the first chamber of multiple membrane stack units in sequence. The ferrous ions in the first electrode plate lose electrons and are oxidized, which causes the lithium ions in the lithium iron phosphate to be released to form iron phosphate. The lithium ions enter the lithium-rich liquid for further enrichment. After leaving the electro-deintercalation / deintercalation membrane stack 101, the lithium-rich liquid returns to the lithium-rich liquid storage tank 201 through the fifth valve 505.

[0034] By alternating between the two working states, the lithium resources in the brine can be enriched in the lithium-rich solution.

[0035] In this invention, the control system adjusts the brine flow rate by controlling the motor power of the liquid pump, and the parameters in the electro-deintercalation and lithium extraction process satisfy the following equation (1): D = Equation (1); in, D is the balance coefficient of the electro-deintercalation lithium extraction system, and its value ranges from D∈[0.95,1.05]. Q represents the brine flow rate, in L / h; This represents the lithium ion concentration in the brine, expressed in g / L. S represents the area of ​​the lithium extraction electrode, in m². 2 ; k1 is the efficiency coefficient of the brine in providing lithium ions per unit plate area, and its value is 1 / m. 2 ; B is the lithium extraction frequency factor, taken as an empirical value of 5.72 × 10⁻⁶. 3 cm 2 / (V·min); The voltage applied during the electro-deintercalation / extraction of lithium, with a range of values. ∈[0.35,1.1]V; The density of the iron phosphate coating on the lithium electrode surface is measured in mg / cm³. 2 ; E is the apparent activation energy, which is 18.9 kJ / mol; R is the molar gas constant, with a value of 8.314 J / (mol·K); T represents the brine temperature during the electro-deintercalation and extraction of lithium, in K. N is the number of membrane stack units; The correction parameters satisfy the following formula: , The attenuation coefficient is set to 0.01h. -1 ; t is the time for lithium extraction and deintercalation, t∈[0,24]h.

[0036] The invention will now be described in detail with reference to specific embodiments. Continuous experiments were conducted using the calculated flow rate as the experimental condition. To ensure consistency of the experimental conditions, a continuous brine supply method was adopted, meaning the brine was no longer recycled for lithium extraction, ensuring that the concentration of brine ions flowing into the membrane stack remained constant. The flow rate detection instrument used in the experiment was a Yokogawa DN series electromagnetic flowmeter from Japan.

[0037] Example 1 The experiment used an electro-deintercalation lithium extraction device with a 24-layer membrane stack structure, where the electrode area of ​​each layer was 1 m². 2 Set the slot voltage =0.5V, =2500 mg / cm 2 At a temperature of T = 298.15 K, the Li content of the brine was measured. + concentration =0.88g / L, take D=1, C T =0.2. The optimal brine flow rate calculated by simulation is approximately 6.84 × 10⁻⁶. 3 L / h. Based on the estimated value, brine was pumped into the membrane stack. Simultaneously, multiple membrane stacks (based on comparative experiments) were set up for electrodeposition and extraction of lithium. Every hour, the electrode plates were removed for lithium extraction, and the Li content in the extraction solution was measured. + The lithium content was calculated, and the lithium extraction capacity per hour ((Li) mg / g(FePO4)) was obtained. The experimental parameters are shown in Table 1, the changes in lithium extraction capacity are shown in Table 2, and the trend of lithium extraction capacity is shown in [Table 2]. Figure 4 After one lithium extraction cycle, the electrodes were switched, and the operating state of the electro-deintercalation lithium extraction system was changed to perform lithium extraction again. The above steps were repeated, and the cycle performance of the electrodes was measured after 100 cycles, as shown in Table 4.

[0038] Example 2 The experiment used an electro-deintercalation lithium extraction device with a 24-layer membrane stack structure, where the electrode area of ​​each layer was 1 m². 2 Set the slot voltage =1.1V, =2500 mg / cm 2 At a temperature of T = 298.15 K, the Li content of the brine was measured. + concentration =0.88g / L, take D=1, C T =0.2. The optimal brine flow rate calculated by simulation is approximately 1.5 × 10⁻⁶. 4 L / h. Based on the estimated value, brine was pumped into the membrane stack. Simultaneously, multiple membrane stacks (based on comparative experiments) were set up for electrodeposition and extraction of lithium. Every hour, the electrode plates were removed for lithium extraction, and the Li content in the extraction solution was measured. + The lithium content was calculated, and the lithium extraction capacity per hour ((Li) mg / g(FePO4)) was obtained. The experimental parameters are shown in Table 1, the changes in lithium extraction capacity are shown in Table 2, and the trend of lithium extraction capacity is shown in [Table 2]. Figure 5 After one lithium extraction cycle, the electrodes were switched, and the operating state of the electro-deintercalation lithium extraction system was changed to perform lithium extraction again. The above steps were repeated, and the cycle performance of the electrodes was measured after 100 cycles, as shown in Table 4.

[0039] Example 3 The experiment used an electro-deintercalation lithium extraction device with a 24-layer membrane stack structure, where the electrode area of ​​each layer was 1 m².2 Set the slot voltage =0.35V, =2500 mg / cm 2 At a temperature of T = 298.15 K, the Li content of the brine was measured. + concentration =0.88g / L, take D=1, C T =0.2. The optimal brine flow rate calculated by simulation is approximately 4.79 × 10⁻⁶. 3 L / h. Based on the estimated value, brine was pumped into the membrane stack. Simultaneously, multiple membrane stacks (based on comparative experiments) were set up for electrodeposition and extraction of lithium. Every hour, the electrode plates were removed for lithium extraction, and the Li content in the extraction solution was measured. + The lithium content was calculated, and the lithium extraction capacity per hour ((Li) mg / g(FePO4)) was obtained. The experimental parameters are shown in Table 1, the changes in lithium extraction capacity are shown in Table 2, and the trend of lithium extraction capacity is shown in [Table 2]. Figure 6 After one lithium extraction cycle, the electrodes were switched, and the operating state of the electro-deintercalation lithium extraction system was changed to perform lithium extraction again. The above steps were repeated, and the cycle performance of the electrodes was measured after 100 cycles, as shown in Table 4.

[0040] Example 4 The experiment used an electro-deintercalation lithium extraction device with a 24-layer membrane stack structure, where the electrode area of ​​each layer was 1 m². 2 Set the slot voltage =0.5V, =5000 mg / cm 2 At a temperature of T = 298.15 K, the Li content of the brine was measured. + concentration =0.88g / L, take D=1, C T =0.2. The optimal brine flow rate calculated by simulation is approximately 1.36 × 10⁻⁶. 4 L / h. Based on the estimated value, brine was pumped into the membrane stack. Simultaneously, multiple membrane stacks (based on comparative experiments) were set up for electrodeposition and extraction of lithium. Every hour, the electrode plates were removed for lithium extraction, and the Li content in the extraction solution was measured. + The lithium content was calculated, and the lithium extraction capacity per hour ((Li) mg / g(FePO4)) was obtained. The experimental parameters are shown in Table 1, the changes in lithium extraction capacity are shown in Table 2, and the trend of lithium extraction capacity is shown in [Table 2]. Figure 7 After one lithium extraction cycle, the electrodes were switched, and the operating state of the electro-deintercalation lithium extraction system was changed to perform lithium extraction again. The above steps were repeated, and the cycle performance of the electrodes was measured after 100 cycles, as shown in Table 4.

[0041] Example 5 The experiment used an electro-deintercalation lithium extraction device with a 24-layer membrane stack structure, where the electrode area of ​​each layer was 1 m². 2 Set the slot voltage =0.5V, =1500 mg / cm 2 At a temperature of T = 298.15 K, the Li content of the brine was measured. + concentration =0.88g / L, take D=1, C T =0.2. The optimal brine flow rate calculated by simulation is approximately 4.1 × 10⁻⁶. 3 L / h. Based on the estimated value, brine was pumped into the membrane stack. Simultaneously, multiple membrane stacks (based on comparative experiments) were set up for electrodeposition and extraction of lithium. Every hour, the electrode plates were removed for lithium extraction, and the Li content in the extraction solution was measured. + The lithium content was calculated, and the lithium extraction capacity per hour ((Li) mg / g(FePO4)) was obtained. The experimental parameters are shown in Table 1, the changes in lithium extraction capacity are shown in Table 2, and the trend of lithium extraction capacity is shown in [Table 2]. Figure 8 After one lithium extraction cycle, the electrodes were switched, and the operating state of the electro-deintercalation lithium extraction system was changed to perform lithium extraction again. The above steps were repeated, and the cycle performance of the electrodes was measured after 100 cycles, as shown in Table 4.

[0042] Example 6 The experiment used an electro-deintercalation lithium extraction device with a 24-layer membrane stack structure, where the electrode area of ​​each layer was 1 m². 2 Set the slot voltage =0.5V, =2500 mg / cm 2 At a temperature of T = 298.15 K, the Li content of the brine was measured. + concentration =0.88g / L, take D=1. Continuous electro-extraction and extraction of lithium, every hour according to... Calculate C T Subsequently, the optimal brine flow rate for that hour was calculated using simulation, and the brine flow rate pumped to the membrane stack was adjusted based on the estimated value. After one lithium extraction cycle, the electrode plates were removed for delithiation, and the Li content in the delithiation solution was measured. + The lithium content was determined, and the lithium extraction capacity ((Li) mg / g(FePO4)) within that cycle was obtained. Experimental parameters and lithium extraction capacities are shown in Table 3. The electrodes were then swapped, and the operating state of the electro-deintercalation lithium extraction system was switched for another lithium extraction cycle. The above steps were repeated 100 times, and the cycle performance of the electrodes was measured, as shown in Table 4.

[0043] Comparative Example 1 The only difference from Example 1 is that the brine flow rate is approximately 8.28 × 10⁻⁶. 3 L / h.

[0044] Comparative Example 2 The only difference from Example 1 is that the brine flow rate is approximately 5.55 × 10⁻⁶. 3 L / h.

[0045] Comparative Example 3 The only difference from Example 2 is that the brine flow rate is approximately 1.82 × 10⁻⁶. 4 L / h.

[0046] Comparative Example 4 The only difference from Example 2 is that the brine flow rate is approximately 1.21 × 10⁻⁶. 4 L / h.

[0047] Comparative Example 5 The only difference from Example 3 is that the brine flow rate is approximately 5.27 × 10⁻⁶. 3 L / h.

[0048] Comparative Example 6 The only difference from Example 3 is that the brine flow rate is approximately 4.31 × 10⁻⁶. 3 L / h.

[0049] Comparative Example 7 The only difference from Example 4 is that the brine flow rate is approximately 1.50 × 10⁻⁶. 4 L / h.

[0050] Comparative Example 8 The only difference from Example 4 is that the brine flow rate is approximately 1.23 × 10⁻⁶. 4 L / h.

[0051] Comparative Example 9 The only difference from Example 5 is that the brine flow rate is approximately 4.97 × 10⁻⁶. 3 L / h.

[0052] Comparative Example 10 The only difference from Example 5 is that the brine flow rate is approximately 3.32 × 10⁻⁶. 3 L / h.

[0053] Comparative Example 11 The only difference from Example 6 is that the brine flow rate is maintained at 8.28 × 10⁻⁶. 3 L / h.

[0054] Comparative Example 12 The only difference from Example 6 is that the brine flow rate is maintained at 5.55 × 10⁻⁶. 3 L / h.

[0055] Table 1

[0056] Table 2

[0057] Table 3

[0058] Table 4

[0059] Based on the experimental results in Table 2 and the appendix Figure 4-8 It can be seen that under different voltage and iron phosphate coating densities, the brine flow rate calculated by the theory D within the scope of this invention can achieve a very ideal lithium extraction efficiency. However, when D is not within the scope of this invention, or when the brine flow rate is lower than the theoretical estimate, the lithium extraction efficiency decreases significantly; or when the brine flow rate is greater than the theoretical estimate, the lithium extraction efficiency does not improve or does not improve significantly. Through the comparison of brine flow rate with lithium extraction efficiency under the above different conditions, it can be seen that the estimated brine flow rate value can ensure the lithium extraction efficiency. According to the experimental results in Table 3, under continuous lithium extraction conditions, the brine flow rate calculated based on the gradually changing correction parameters can still achieve a good lithium extraction efficiency. When the brine flow rate remains lower than the theoretical estimate, the lithium extraction efficiency is significantly lower; when the brine flow rate remains greater than the theoretical estimate, the lithium extraction efficiency does not improve or does not improve significantly. According to the experimental results in Table 4, using the theoretically calculated brine flow rate for cyclic lithium extraction results in good electrode cycling performance. When the brine flow rate is greater than the theoretical estimate, it will significantly affect the electrode cycling performance.

[0060] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. An electro-deintercalation and extraction lithium system, characterized in that, The device includes an electro-deintercalation / deintercalation membrane stack, a brine storage tank, a lithium-rich liquid storage tank, control valves, a liquid pumping device, and a control system. The electro-deintercalation / deintercalation membrane stack includes at least one membrane stack unit, and the membrane stack unit includes a lithium extraction electrode plate. The parameters in the electro-deintercalation and extraction of lithium satisfy the following equation (1): D = Equation (1); in, D is the balance coefficient of the electro-deintercalation lithium extraction system, and its value ranges from D∈[0.95,1.05]. Q represents the brine flow rate, which is 3.32 × 10⁻⁶. 3 ~1.82×10 4 L / h; This represents the lithium ion concentration in the brine, expressed in g / L. S represents the area of ​​the lithium extraction electrode, in m². 2 ; k1 is the efficiency coefficient of the brine in providing lithium ions per unit electrode area, and its value is 1 / m. 2 ; B is the lithium extraction frequency factor, taken as an empirical value of 5.72 × 10⁻⁶. 3 cm 2 / (V·min); The voltage applied during the electro-deintercalation / extraction of lithium, with a range of values. ∈[0.35,1.1]V; The density of the iron phosphate coating on the lithium electrode surface is measured in mg / cm³. 2 ; E is the apparent activation energy, which is 18.9 kJ / mol; R is the molar gas constant, with a value of 8.314 J / (mol·K); T represents the brine temperature during the electro-deintercalation and extraction of lithium, in K. N is the number of membrane stack units; The correction parameters satisfy the following formula: , The attenuation coefficient is 0.01h. -1 ; t is the time for lithium extraction / extraction, t∈[0,24]h; The control system adjusts the brine flow rate according to the correction parameters.

2. The lithium extraction and intercalation system according to claim 1, characterized in that, The area of ​​the electrode plate is 0.1~5m². 2 .

3. The lithium extraction and intercalation system according to claim 1, characterized in that, The coating density ≤5000mg / cm 2 .

4. The lithium extraction and deintercalation system according to claim 1, characterized in that, The temperature of the brine is 20~45℃. When performing the calculation of formula (1), the brine temperature is converted in K.

5. The lithium extraction and deintercalation system according to claim 1, characterized in that, The brine storage tank is equipped with a first temperature control device, and the lithium-rich liquid storage tank is equipped with a second temperature control device.

6. The lithium extraction and deintercalation system according to claim 1, characterized in that, The membrane stack unit includes a first separator, a first electrode plate, a second separator, an anion exchange membrane, a third separator, a second electrode plate, and a fourth separator arranged in sequence; the first separator and the second separator form a first chamber, and the third separator and the fourth separator form a second chamber.

7. The lithium extraction and deintercalation system according to claim 6, characterized in that, The electro-deintercalation / deintercalation membrane stack includes multiple membrane stack units, with the first chambers of the multiple membrane stack units connected sequentially by pipes, and the second chambers of the multiple membrane stack units connected sequentially by pipes; and / or, the number of the membrane stack units is 2 to 24.

8. The application of the electro-deintercalation lithium extraction system according to any one of claims 1-7 in lithium extraction production from salt lakes.

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