A cleaning and activating method for an electro-intercalation lithium extraction device

Abstract

This invention belongs to the field of lithium resource extraction technology. It provides a cleaning and activation method for an electro-deintercalation lithium extraction device. The method includes first acid washing both the anode and cathode sides of the device. After acid washing, lithium extraction is performed alternately on both sides in a lithium-rich solution to replace and remove impurities. Then, an activation solution is introduced to the cathode side and a lithium-rich solution is introduced to the anode side. Electricity is applied to insert lithium ions on the anode side and deintercalate lithium ions on the cathode side, thus completing the electrode activation. This method not only cleans the electrode plates and membrane surfaces inside the device but also restores the activity of the electrode materials using the activation solution, eliminating the negative impact of impurities on the lithium extraction performance of the device. The method is simple, convenient, and effectively improves the operational stability of the equipment.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion resource extraction technology, and relates to a cleaning and activation method for an electro-deintercalation lithium extraction device. Background Technology

[0002] Lithium metal is the lightest metal by weight and has high chemical reactivity. Lithium and its compounds have wide applications in modern industry, especially in high-tech fields, and are among the most important materials in high-tech areas. Due to its excellent properties, in addition to its use in nuclear energy, aerospace, and defense industries, it is also finding increasingly widespread applications in civilian industries, such as automotive batteries. Therefore, the demand for lithium resources is growing rapidly.

[0003] Lithium extraction methods are mainly divided into extraction from ore resources and extraction from liquid lithium resources, depending on the lithium raw material. Liquid lithium resources, especially brine resources in salt lakes, are often extracted from lithium ions using electrochemical deintercalation methods.

[0004] Electrochemical deintercalation / extraction refers to the process of separating and extracting lithium ions using the principles of lithium batteries. Under a direct current electric field, lithium ions are adsorbed from the lithium-containing solution in the cathode-side chamber by a lithium-deficient material on the cathode side. Simultaneously, lithium ions are desorbed from the lithium-rich material on the anode side and transferred to the solution in the anode-side chamber. The anode and cathode chambers are separated by an anion exchange membrane, which prevents lithium ions from entering the cathode chamber from the anode chamber, thus achieving the separation and extraction of lithium ions. Compared to traditional lithium extraction methods such as evaporation crystallization and precipitation, which have recovery rates of only 40%–50%, electrochemical deintercalation / extraction offers a higher recovery rate, reaching 90% or more, and significantly shortens the production cycle.

[0005] However, there are still some unresolved issues in using electrochemical lithium extraction devices for electrochemical lithium extraction. For example, lithium extraction from liquid lithium ore resources easily leads to contamination of the electrode coating material (i.e., lithium adsorption material) and the anion exchange membrane. Specifically, organic matter, magnesium / calcium ions that easily cause scaling, and suspended solids can deposit on the surface of the material and membrane, while impurity ions in the lithium-containing solution (such as Na+) can also cause contamination. + Impurity ions can easily penetrate the coating material and combine with it. Furthermore, the high voltage at which impurity ions are extracted from the electrode plate prevents them from being extracted during the electro-deintercalation lithium extraction process. Over time, the adsorbent material on the electrode plate continuously combines with impurity ions, reducing material activity and ultimately leading to a significant decrease in lithium extraction capacity and efficiency, severely impacting normal production processes.

[0006] Currently, the maintenance methods for electrodeposition-extraction (EEIE) lithium extraction devices generally involve water washing, and the cleaning of the internal anion exchange membranes is generally done using acid washing. Existing water washing and acid washing processes only clean the membrane and electrode surfaces, offering limited repair benefits to the equipment's performance. Due to the characteristics of EEIE devices, the electrode plates have a significant impact on lithium extraction efficiency. However, the weakening lithium extraction capacity of current EEIE devices is mainly due to the deactivation of lithium adsorbent materials in the electrode plates, but there are currently no measures in the routine maintenance of EEIE devices to repair the lithium adsorbent materials in the electrode plates.

[0007] Therefore, seeking an efficient method for cleaning the electro-deintercalation / deintercalation equipment and activating the lithium adsorption material to improve the efficiency of lithium extraction and the service life of the equipment in practical applications is of great practical significance. Summary of the Invention

[0008] In view of the problems existing in the prior art, the purpose of this invention is to provide a cleaning and activation method for an electro-lithiation and extraction device. The method includes first acid washing of both the anode and cathode sides within the device; after acid washing, alternating lithium extraction processes on both sides in a lithium-rich solution to achieve impurity ion replacement and removal; then, an activation solution is introduced to the cathode side and a lithium-rich solution is introduced to the anode side; and electricity is applied to cause lithium ions to be inserted on the anode side and extracted on the cathode side, thus completing the electrode activation. This method not only cleans the electrode plates and membrane surfaces inside the device but also restores the activity of the electrode materials using the activation solution, eliminating the negative impact of impurities on the lithium extraction performance of the device. The method is simple and convenient, and can effectively improve the operational stability of the equipment.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides a cleaning and activation method for an electro-deintercalation lithium extraction device, the cleaning and activation method comprising:

[0011] Acid washing solution is simultaneously introduced into both the cathode and anode sides of the lithium extraction and deintercalation device for acid washing.

[0012] After acid washing, the cathode and anode sides are alternately subjected to electro-deintercalation and extraction of lithium in a lithium-rich solution to complete at least two lithium extraction cycles for impurity ion replacement.

[0013] After impurity ion replacement, an activation solution is introduced to the cathode side and a lithium-rich solution is introduced to the anode side. When electricity is applied, lithium ions are inserted into the anode side and extracted from the cathode side to activate the electrode.

[0014] The deactivation of the coating materials (or lithium extraction materials or adsorption materials) on the anode and cathode in the electrolytic lithium extraction device is due to the combination of impurity ions in the liquid lithium ore resources with the coating materials, which reduces the activity of the materials, thereby reducing the capacity of the electrode plates and causing various contaminations, including the blockage of particulate matter at the device inlet and the scaling of calcium and magnesium ions on the surface of the electrode plates and anion exchange membranes. All of these affect the lithium extraction effect and the electrode plate capacity. Therefore, this invention proposes a cleaning and activation method for the electrolytic lithium extraction device.

[0015] In the cleaning and activation method described in this invention, acid washing is first used to preliminarily wash out insoluble impurities in various parts of the device, such as the inlet and outlet, the circulation tanks on the anode and cathode sides, the chambers and electrode plates, and the anion exchange membrane, thereby reducing the impurity content in the device.

[0016] Furthermore, the pickling process is divided into forward washing and backwashing. In the forward washing process, the pickling solution enters the device from the feed inlet and leaves the device from the discharge outlet. In the backwashing process, the pickling solution enters the device from the discharge outlet and leaves the device from the feed inlet. The present invention preferably uses backwashing to remove impurities from the inlet of the guide plate inside the device.

[0017] The cleaning and activation method of this invention, after acid washing, deeply removes impurities from the electrode plates by alternating lithium extraction on the anode and cathode sides. Specifically, during the impurity ion replacement process, a lithium-rich solution is first introduced into the anode side of the electro-deintercalation / deintercalation device, and fresh water is introduced into the cathode side. The device is powered on, causing lithium insertion on the anode side and deintercalation on the cathode side. Then, the power supply polarity is switched, and the introduction of lithium-rich solution and fresh water is switched, causing lithium insertion on the cathode side and deintercalation on the anode side. This constitutes one lithium extraction cycle. At least two lithium extraction cycles are completed by repeatedly alternating lithium extraction and deintercalation operations, ensuring that impurity ions on the deintercalation side electrode plate are removed along with lithium, while the lithium extraction side electrode plate directly extracts lithium ions from the lithium-rich solution, eliminating the possibility of impurity ions binding to the electrode plate adsorption material. During the multiple alternating lithium extraction processes, each electrode plate acts as both the cathode and anode side multiple times, allowing impurity ions (such as sodium ions) bound to the electrode plate material to be removed, while lithium ions are re-intercalated onto the electrode plate, reducing the impurity ion content on the electrode plate.

[0018] The cleaning and activation method of this invention activates the electrode plates after impurity removal using an activation solution. During the electrode plate activation process, as lithium ions are released from the cathode electrode plate, the current continuously decreases. Components in the activation solution, such as reducing agents, can be oxidized on the cathode side to provide electrons, allowing the entire device to continue operating at a higher current for the electrochemical reaction. By directly extracting lithium from the lithium-rich solution, the lithium content on the electrode plates is further increased, thereby activating the electrode plates.

[0019] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The technical objectives and beneficial effects of the present invention can be better achieved and realized through the following technical solutions.

[0020] As a preferred embodiment of the present invention, the pickling solution includes at least one of acetic acid, citric acid, or hydrochloric acid with a pH of 3 to 5. Typical but non-limiting combinations include combinations of acetic acid and citric acid, acetic acid and hydrochloric acid, or citric acid and hydrochloric acid, with hydrochloric acid being preferred. The pH of 3 to 5 can be, for example, 3, 3.2, 3.4, 3.6, 3.8, 4, 4.2, 4.4, 4.6, 4.8, or 5, but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0021] It should be noted that pickling solutions with excessively high pH will fail to dissolve the scale on the electrode plates, while those with excessively low pH will cause the coating material on the electrode plates to dissolve. The pH of various pickling solutions used should preferably be kept within the above-mentioned range.

[0022] Preferably, the pickling solution is introduced at a rate of 6 to 8 cm / s, such as 6 cm / s, 6.5 cm / s, 7 cm / s, 7.5 cm / s, or 8 cm / s, but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0023] It should be noted that the rate at which the pickling solution is introduced affects the reaction rate between hydrogen ions and the scale on the electrode plate. Too low a rate of introduction will result in a slow reaction, which may lead to a local increase in the pH of the pickling solution and affect the reaction. Too high a rate of introduction will not only increase the energy consumption of the pump, but also the rate of increase in reaction speed will become smaller and smaller as the rate of introduction increases. Similarly, the rate of introduction of lithium-rich solution and activation solution follows a similar principle.

[0024] Preferably, the pickling time is 10 to 60 minutes, such as 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes or 60 minutes, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0025] As a preferred technical solution of the present invention, after the acid washing and before the impurity ion replacement, the cathode side and the anode side are simultaneously washed with water for 10 to 60 minutes, such as 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes or 60 minutes, but not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0026] As a preferred embodiment of the present invention, the lithium-rich liquid contains lithium salts, including lithium chloride and / or lithium sulfate, preferably lithium chloride.

[0027] Preferably, the lithium concentration in the lithium-rich solution is 1 to 2 g / L, such as 1 g / L, 1.2 g / L, 1.4 g / L, 1.6 g / L, 1.8 g / L or 2 g / L, but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0028] Preferably, the amount of lithium-rich liquid introduced is controlled to be 100% to 120% of the maximum lithium capacity on the cathode or anode side, based on the total lithium content of the lithium-rich liquid in all chambers. For example, 100%, 105%, 110%, 115%, or 120%, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0029] As a preferred technical solution of the present invention, the impurity ion replacement is completed in 2 to 6 lithium extraction cycles, for example, 2, 3, 4, 5 or 6 cycles can be completed.

[0030] As a preferred embodiment of the present invention, the activating solution contains a reducing agent, which includes at least one of sodium sulfite, sodium metabisulfite, or vitamin C. Typical but non-limiting combinations include combinations of sodium sulfite and sodium metabisulfite, combinations of sodium sulfite and vitamin C, combinations of sodium metabisulfite and vitamin C, etc., with sodium sulfite being the preferred choice.

[0031] Preferably, the mass concentration of the reducing agent in the activating solution is 0.5% to 1%, such as 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0032] It should be noted that the reducing agent is the substrate of the reaction during the activation process. If the concentration of the reducing agent in the activation solution is too low, the activation of the electrode plate will not be thorough. It has been verified that a better activation effect can be achieved within the above-mentioned preferred range.

[0033] The reducing agent described in this invention is used to undergo a redox reaction with the coating material on the electrode plate during the activation process, so as to restore the lithium extraction capability of the electrode plate.

[0034] As a preferred technical solution of the present invention, the activation voltage is 3 to 3.5V, such as 3V, 3.1V, 3.2V, 3.3V, 3.4V or 3.5V, preferably 3.5V, but not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0035] This invention aims to ensure the complete activation of the electrode plates by controlling the range of the energizing voltage during activation.

[0036] Preferably, the activation time is 2 to 4 hours, such as 2 hours, 2.2 hours, 2.4 hours, 2.6 hours, 2.8 hours, 3 hours, 3.2 hours, 3.4 hours, 3.6 hours, 3.8 hours, or 4 hours, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0037] As a preferred technical solution of the present invention, the temperature of the pickling solution, lithium-rich solution and activation solution is 30-35°C, such as 30°C, 31°C, 32°C, 33°C, 34°C or 35°C, but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0038] As a preferred technical solution of the present invention, the pickling solution, lithium-rich solution and activation solution are all continuously circulated into the corresponding cathode side and / or anode side through a circulation device.

[0039] As a preferred embodiment of the present invention, the cleaning and activation method includes:

[0040] After emptying the internal materials from both the cathode and anode sides of the lithium extraction and deintercalation device, the pickling solution is placed in the cathode liquid circulation tank and the anode liquid circulation tank. The circulation pump is turned on, and the pickling solution is simultaneously pumped into the cathode chamber and the anode chamber at a speed of 6-8 cm / s. The cathode plate and the anode plate are circulated and pickled for 10-60 minutes, and then the pickling solution is drained. RO water is placed in the cathode liquid circulation tank and the anode liquid circulation tank. The circulation pump is turned on, and the RO water is simultaneously pumped into the cathode chamber and the anode chamber. The cathode plate and the anode plate are circulated and washed for 10-60 minutes, and then the liquid in the chamber is drained.

[0041] After washing with water, the lithium-rich solution is placed in the anolyte circulation tank, and water is placed in the catholyte circulation tank. The circulation pump is turned on to pump the lithium-rich solution into the anode chamber and the water into the cathode chamber. Electrolytic deintercalation and extraction of lithium is performed, causing lithium ions to be inserted into the anode plate and deintercalated from the cathode plate. After the charge-discharge capacity reaches the initial value, the power is stopped, completing the first lithium extraction cycle. The polarity of the power supply applied to the cathode and anode plates is switched, and the lithium-rich solution is pumped into the cathode chamber and the water into the anode chamber. Electrolytic deintercalation and extraction of lithium is performed again, causing lithium ions to be inserted into the cathode plate and deintercalated from the anode plate. After the charge-discharge capacity reaches the initial value, the power is stopped, completing the second lithium extraction cycle. This process is repeated 2 to 6 times to replace impurity ions and drain the liquid from the chamber.

[0042] After impurity ion replacement, the activation solution and lithium-rich solution are placed in the cathode liquid circulation tank and the anode liquid circulation tank, respectively. The circulation pump is turned on to pump the activation solution into the cathode chamber and the lithium-rich solution into the anode chamber. When the voltage is 3 to 3.5V, the anode plate is energized to insert lithium ions and the cathode plate is de-energized. The activation process is carried out for 2 to 4 hours to complete the plate activation.

[0043] Compared with existing technical solutions, the present invention has at least the following beneficial effects:

[0044] The cleaning and activation method for the electro-deintercalation lithium extraction device provided by this invention involves initial cleaning of the internal electrode plates and membrane surfaces through online acid washing, followed by alternating lithium extraction processes on the anode and cathode sides in a lithium-rich solution to achieve impurity ion replacement and deep removal. Finally, the activity of the electrode plate material is restored using an activation solution, eliminating its negative impact on the electro-deintercalation lithium extraction device, thereby improving the device's lithium extraction capacity and efficiency. The cleaning and activation method is simple and convenient, and the acid washing solution, lithium-rich solution, and activation solution are inexpensive and readily available, effectively improving the operational stability of the equipment. This method, which can restore the activity of the electro-deintercalation electrode plate material, is conducive to promoting the further large-scale application and development of the electro-deintercalation process in lithium extraction from salt lakes. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of an electro-deintercalation lithium extraction device;

[0046] In the diagram: 1-Cathode liquid circulation tank, 2-Anode liquid circulation tank, 3-Electrochemical deintercalation tank, 4-Infeed side valve group, 5-Discharge side valve group;

[0047] Figure 2 This is a schematic flowchart of the cleaning and activation method for the described lithium electrolysis extraction device. Detailed Implementation

[0048] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0049] Those skilled in the art will understand that the embodiments described are merely illustrative of the invention and should not be construed as limiting the invention.

[0050] The following embodiments and comparative examples all use an electro-extraction lithium extraction device, such as... Figure 1 As shown, the electrochemical deintercalation and extraction lithium device includes an electrochemical deintercalation tank 3, which is provided with a cathode chamber and an anode chamber, separated by an anion exchange membrane. Along the flow direction of the material, the two ends of the electrochemical deintercalation and extraction tank 3 are respectively connected to a feed-side valve group 4 and a discharge-side valve group 5. The electrochemical deintercalation and extraction lithium device also includes a cathode liquid circulation tank 1 and an anode liquid circulation tank 2, which are connected to the feed-side valve group 4 and the discharge-side valve group 5 and form a circulation path.

[0051] Example 1

[0052] This embodiment provides a cleaning and activation method for an electro-deintercalation lithium extraction device, such as... Figure 2 As shown, the cleaning and activation method includes:

[0053] (1) Pickling: The water temperature is raised to 30°C using a heating device, and the pH is adjusted to 3 using hydrochloric acid to prepare a pickling solution. After emptying the internal materials of both the cathode and anode sides of the lithium deintercalation and extraction device, the pickling solution is placed in the cathode liquid circulation tank and the anode liquid circulation tank. The circulation pump is turned on, and the pickling solution is pumped into the cathode chamber and the anode chamber at a speed of 7 cm / s. The cathode plate and the anode plate are circulated and pickled for 30 minutes, and then the pickling solution is drained. RO water is placed in the cathode liquid circulation tank and the anode liquid circulation tank. The circulation pump is turned on, and the RO water is pumped into the cathode chamber and the anode chamber at the same time. The cathode plate and the anode plate are circulated and washed for 30 minutes, and then the washing solution is drained.

[0054] (2) Impurity ion replacement: After washing with water, the water temperature is raised to 30°C using a heating device. A lithium-rich solution with a lithium concentration of 2 g / L is prepared using lithium chloride. The lithium-rich solution is placed in the anolyte circulation tank, and the water is placed in the cathode circulation tank. The circulation pump is turned on to pump the lithium-rich solution into the anode chamber and the water into the cathode chamber. The negative terminal of the power supply is connected to the anode plate, and the positive terminal of the power supply is connected to the cathode plate. The voltage is set to 3.5V. The cathode plate and the anode plate are energized to perform electro-deintercalation and lithium extraction, so that the anode plate inserts lithium ions and the cathode plate removes lithium ions. After the charge and discharge capacity reaches the initial value, the power supply is stopped, and the first lithium extraction cycle is completed. The positive and negative terminals of the power supply are switched, the lithium-rich solution is pumped into the cathode chamber, and the water is pumped into the anode chamber to continue the lithium extraction operation, so that the cathode plate inserts lithium ions and the anode plate removes lithium ions. After the charge and discharge capacity reaches the initial value, the power supply is stopped, and the second lithium extraction cycle is completed. The lithium extraction cycle is carried out continuously and alternately for a total of 4 lithium extraction cycles to perform impurity ion replacement and drain the liquid in the chamber.

[0055] (3) Plate activation: The water temperature is raised to 30°C using a heating device. Sodium sulfite, the reducing agent, is added to the water. The solution is continuously added and stirred to dissolve the solution, resulting in a sodium sulfite activation solution with a mass fraction of 0.5%. A lithium-rich solution with a lithium concentration of 2 g / L is prepared using lithium chloride. The activation solution and the lithium-rich solution are placed in the cathode liquid circulation tank and the anode liquid circulation tank, respectively. The circulation pump is turned on to pump the activation solution into the cathode chamber and the lithium-rich solution into the anode chamber. The equipment is powered on, with the negative terminal of the power supply connected to the anode plate and the positive terminal connected to the cathode plate. The voltage is set to 3.5V. Powering on the anode plate causes lithium ions to be inserted and the cathode plate to be released. The process is repeated for 2 hours. After completion, the internal solution is drained to complete the plate activation.

[0056] Example 2

[0057] This embodiment provides a cleaning and activation method for an electro-deintercalation lithium extraction device, the cleaning and activation method comprising:

[0058] (1) Pickling: The water temperature is raised to 32°C using a heating device, and the pH is adjusted to 4 using acetic acid and hydrochloric acid to prepare a pickling solution. After emptying the internal materials of the cathode and anode sides of the lithium deintercalation and extraction device, the pickling solution is placed in the cathode liquid circulation tank and the anode liquid circulation tank. The circulation pump is turned on, and the pickling solution is pumped into the cathode chamber and the anode chamber at a speed of 6 cm / s. The cathode plate and the anode plate are circulated and pickled for 60 minutes, and then the pickling solution is drained. RO water is placed in the cathode liquid circulation tank and the anode liquid circulation tank. The circulation pump is turned on, and the RO water is pumped into the cathode chamber and the anode chamber at the same time. The cathode plate and the anode plate are circulated and washed for 60 minutes, and then the washing solution is drained.

[0059] (2) Impurity ion replacement: After washing with water, the water temperature is raised to 32°C using a heating device. A lithium-rich solution with a lithium concentration of 1.3 g / L is prepared using lithium chloride. The lithium-rich solution is placed in the anolyte circulation tank, and the water is placed in the cathode circulation tank. The circulation pump is turned on to pump the lithium-rich solution into the anode chamber and the water into the cathode chamber. The negative terminal of the power supply is connected to the anode plate, and the positive terminal of the power supply is connected to the cathode plate. The voltage is set to 3.2V. The cathode plate and the anode plate are energized to perform electro-deintercalation and lithium extraction, so that the anode plate inserts lithium ions and the cathode plate removes lithium ions. After the charge and discharge capacity reaches the initial value, the power supply is stopped, and the first lithium extraction cycle is completed. The positive and negative terminals of the power supply are switched, the lithium-rich solution is pumped into the cathode chamber, and the water is pumped into the anode chamber, and the lithium extraction operation is continued, so that the cathode plate inserts lithium ions and the anode plate removes lithium ions. After the charge and discharge capacity reaches the initial value, the power supply is stopped, and the second lithium extraction cycle is completed. The lithium extraction cycle is carried out continuously and alternately for a total of 6 lithium extraction cycles to perform impurity ion replacement and drain the liquid in the chamber.

[0060] (3) Plate activation: The water temperature is raised to 32°C using a heating device. Vitamin C, the reducing agent, is added to the water. The mixture is continuously added and stirred to dissolve the vitamin C, resulting in a vitamin C activation solution with a mass fraction of 0.8%. A lithium-rich solution with a lithium concentration of 1.3 g / L is prepared using lithium chloride. The activation solution and the lithium-rich solution are placed in the cathode liquid circulation tank and the anode liquid circulation tank, respectively. The circulation pump is turned on to pump the activation solution into the cathode chamber and the lithium-rich solution into the anode chamber. The equipment is powered on, with the negative terminal of the power supply connected to the anode plate and the positive terminal connected to the cathode plate. The voltage is set to 3.2V. Powering on the anode plate causes lithium ions to be inserted and the cathode plate to be released. The process is repeated for 3 hours. After completion, the internal solution is drained to complete the plate activation.

[0061] Example 3

[0062] This embodiment provides a cleaning and activation method for an electro-deintercalation lithium extraction device, the cleaning and activation method comprising:

[0063] (1) Pickling: The water temperature is raised to 35°C using a heating device, and the pH is adjusted to 5 using citric acid and hydrochloric acid to prepare a pickling solution. After emptying the internal materials of both the cathode and anode sides of the lithium deintercalation and extraction device, the pickling solution is placed in the cathode liquid circulation tank and the anode liquid circulation tank. The circulation pump is turned on, and the pickling solution is pumped into the cathode chamber and the anode chamber at a speed of 8 cm / s. The cathode plate and the anode plate are circulated and pickled for 20 minutes, and then the pickling solution is drained. RO water is placed in the cathode liquid circulation tank and the anode liquid circulation tank, and the circulation pump is turned on, and the RO water is pumped into the cathode chamber and the anode chamber at the same time. The cathode plate and the anode plate are circulated and washed for 20 minutes, and then the washing solution is drained.

[0064] (2) Impurity ion replacement: After washing with water, the water temperature is raised to 35°C using a heating device. A lithium-rich solution with a lithium concentration of 1.5 g / L is prepared using lithium chloride. The lithium-rich solution is placed in the anolyte circulation tank, and the water is placed in the cathode circulation tank. The circulation pump is turned on to pump the lithium-rich solution into the anode chamber and the water into the cathode chamber. The negative terminal of the power supply is connected to the anode plate, and the positive terminal of the power supply is connected to the cathode plate. The voltage is set to 3.5V. The cathode plate and the anode plate are energized to perform electro-deintercalation and lithium extraction, so that the anode plate inserts lithium ions and the cathode plate removes lithium ions. After the charge and discharge capacity reaches the initial value, the power supply is stopped, and the first lithium extraction cycle is completed. The positive and negative terminals of the power supply are switched, the lithium-rich solution is pumped into the cathode chamber, and the water is pumped into the anode chamber, and the lithium extraction operation is continued, so that the cathode plate inserts lithium ions and the anode plate removes lithium ions. After the charge and discharge capacity reaches the initial value, the power supply is stopped, and the second lithium extraction cycle is completed. The lithium extraction cycle is carried out continuously and alternately for a total of 4 lithium extraction cycles to perform impurity ion replacement and drain the liquid in the chamber.

[0065] (3) Plate activation: The water temperature is raised to 35°C using a heating device. Sodium metabisulfite, the reducing agent, is added to the water. The solution is continuously added and stirred to dissolve the solution, resulting in a sodium metabisulfite activation solution with a mass fraction of 1%. A lithium-rich solution with a lithium concentration of 1.5 g / L is prepared using lithium chloride. The activation solution and the lithium-rich solution are placed in the cathode liquid circulation tank and the anode liquid circulation tank, respectively. The circulation pump is turned on to pump the activation solution into the cathode chamber and the lithium-rich solution into the anode chamber. The equipment is powered on, with the negative terminal of the power supply connected to the anode plate and the positive terminal connected to the cathode plate. The voltage is set to 3.5V. Powering on the anode plate causes lithium ions to be inserted and the cathode plate to be released. The process is repeated for 4 hours. After completion, the internal solution is drained to complete the plate activation.

[0066] Comparative Example 1

[0067] This comparative example provides a cleaning method for an electro-deintercalation lithium extraction device. The cleaning and activation method only performs step (1) and does not perform steps (2) and (3). Except for the above, the other conditions are exactly the same as those in Example 1.

[0068] Comparative Example 2

[0069] This comparative example provides a cleaning method for an electro-deintercalation lithium extraction device. The cleaning and activation method only performs steps (1) and (2), but not step (3). Except for the above, the other conditions are exactly the same as in Example 1.

[0070] Control group 1

[0071] This control group did not undergo the cleaning and activation method described above, and directly used the uncleaned and unactivated lithium extraction device.

[0072] Performance testing

[0073] Lithium extraction tests were conducted on the lithium extraction devices obtained in the examples, comparative examples, and control groups, with a constant lithium extraction running time. The test results are shown in Table 1.

[0074] Table 1

[0075]

[0076] As can be seen from the table above, the cleaning and activation method described in this invention can effectively activate the electrode coating material and remove impurities inside the equipment, effectively improving the lithium extraction capacity of the device and ensuring the long-term stability of the device.

[0077] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0078] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable way without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0079] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A cleaning and activation method for an electro-deintercalation lithium extraction device, characterized in that, The cleaning and activation method includes: Acid washing solution is simultaneously introduced into both the cathode and anode sides of the lithium extraction / deintercalation device for acid washing; the acid washing solution includes at least one of acetic acid, citric acid, or hydrochloric acid with a pH of 3-5. After acid washing, a lithium-rich solution is introduced to the anode side, and water is introduced to the cathode side. Electrolytic deintercalation and extraction of lithium is performed, causing lithium ions to be inserted into the anode plate and removed from the cathode plate. Once the charge / discharge capacity reaches its initial value, the power is stopped, completing the first lithium extraction cycle. The polarity of the power supply applied to the cathode and anode plates is then switched, and the lithium-rich solution is introduced to the cathode side, while a water pump is introduced to the anode side. Electrolytic deintercalation and extraction of lithium is performed again, causing lithium ions to be inserted into the cathode plate and removed from the anode plate. Once the charge / discharge capacity reaches its initial value, the power is stopped, completing the second lithium extraction cycle. This process of alternating electrolytic deintercalation and extraction of lithium on the cathode and anode sides in the lithium-rich solution is repeated to complete at least two lithium extraction cycles for impurity ion replacement. The lithium-rich solution contains lithium salts, including lithium chloride and / or lithium sulfate. After impurity ion replacement, an activation solution is introduced to the cathode side and a lithium-rich solution is introduced to the anode side. Electricity is applied to insert lithium ions into the anode side and extract lithium ions from the cathode side to activate the electrode plate. The activation solution contains a reducing agent, which includes at least one of sodium sulfite, sodium metabisulfite, or vitamin C. In this process, after acid washing and before impurity ion replacement, the cathode side and the anode side are simultaneously washed with water for 10 to 60 minutes.

2. The cleaning and activation method according to claim 1, characterized in that, The pickling solution is introduced at a rate of 6-8 cm / s; And / or, the pickling time is 10~60 min.

3. The cleaning and activation method according to claim 1, characterized in that, The lithium concentration in the lithium-rich solution is 1~2 g / L; And / or, control the flow rate of the lithium-rich solution to be 100% to 120% of the maximum lithium capacity on the cathode or anode side.

4. The cleaning and activation method according to claim 1, characterized in that, The impurity ion replacement process completes 2 to 6 lithium extraction cycles.

5. The cleaning and activation method according to claim 1, characterized in that, The mass concentration of the reducing agent in the activation solution is 0.5%~1%.

6. The cleaning and activation method according to claim 1, characterized in that, The activation voltage is 3~3.5V; And / or, the activation time is 2-4 hours.

7. The cleaning and activation method according to claim 1, characterized in that, The temperature of the pickling solution, lithium-rich solution, and activation solution is 30~35℃.

8. The cleaning and activation method according to claim 1, characterized in that, The pickling solution, lithium-rich solution, and activation solution are all continuously circulated into the corresponding cathode side and / or anode side through a circulation device.

9. The cleaning and activation method according to claim 1, characterized in that, The cleaning and activation method includes: After emptying the internal materials from both the cathode and anode sides of the lithium extraction and deintercalation device, the pickling solution is placed in the cathode liquid circulation tank and the anode liquid circulation tank. The circulation pump is turned on, and the pickling solution is simultaneously pumped into the cathode chamber and the anode chamber at a speed of 6~8 cm / s. The cathode plate and the anode plate are circulated and pickled for 10~60 minutes, and then the pickling solution is drained. RO water is placed in the cathode liquid circulation tank and the anode liquid circulation tank. The circulation pump is turned on, and the RO water is simultaneously pumped into the cathode chamber and the anode chamber. The cathode plate and the anode plate are circulated and washed for 10~60 minutes, and then the liquid in the chamber is drained. After washing with water, place the lithium-rich solution in the anolyte circulation tank and the water in the cathode circulation tank. Turn on the circulation pump to pump the lithium-rich solution into the anode chamber and the water into the cathode chamber. Apply electricity to perform electro-deintercalation and extraction of lithium, so that lithium ions are intercalated into the anode plate and lithium ions are deintercalated into the cathode plate. After the charge and discharge capacity reaches the initial value, stop applying electricity to complete the first lithium extraction cycle. Switch the polarity of the power supply applied to the cathode plate and the anode plate, pump the lithium-rich solution into the cathode chamber and the water into the anode chamber, and apply electricity again to perform electro-deintercalation and extraction of lithium, so that lithium ions are intercalated into the cathode plate and lithium ions are deintercalated into the anode plate. After the charge and discharge capacity reaches the initial value, stop applying electricity to complete the second lithium extraction cycle. Repeat this process for 2 to 6 lithium extraction cycles to replace impurity ions and drain the liquid in the chamber. After impurity ion replacement, the activation solution and lithium-rich solution are placed in the cathode liquid circulation tank and the anode liquid circulation tank, respectively. The circulation pump is turned on to pump the activation solution into the cathode chamber and the lithium-rich solution into the anode chamber. When the voltage is 3~3.5V, the anode plate is energized to insert lithium ions and the cathode plate is de-energized. The activation process is carried out for 2~4 hours to complete the plate activation.

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