A plate cleaning system and method for a flowing slurry electrochemical lithium extraction device

Abstract

The present invention discloses a plate cleaning system and method for a flowing slurry electrochemical lithium extraction device, and relates to the technical field of lithium extraction, wherein a plate cleaning system for a flowing slurry electrochemical lithium extraction device comprises a circulating water washing unit and a dosing cleaning unit. The circulating water washing unit comprises a cathode cleaning water tank, a cathode cleaning water pump, an anode cleaning water tank, an anode cleaning water pump, and a power supply connected to the plate. The cathode cleaning water and the anode cleaning water are respectively circulated to clean the flow channel surfaces on the anode and cathode plates through the cathode cleaning water pump and the anode cleaning water pump. Under an applied voltage, gas is precipitated on the surface of the electrode plate, which helps to peel off the slurry adhered to the surface of the plate flow channel, realize the dredging of the plate flow channel, and ensure the long-term stable operation of the electrochemical lithium extraction device.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium extraction, and in particular to a plate cleaning system and method for a flowing slurry electrochemical lithium extraction device. Background Art

[0002] In recent years, due to the emergence of a large number of electric vehicles, the development of lithium resources has been required. As we all know, the electrochemical method can directly and selectively extract and enrich lithium ions from lithium-containing solutions, and has many advantages such as clean and pollution-free, fast rate, low energy and water consumption, and good selectivity. Chinese patent application 202311116827.4 discloses a system and method for electrochemical selective lithium extraction based on mobile electrodes. The system is respectively equipped with an electrochemical treatment unit, a material input unit, a solid-liquid separation system, and a water washing unit, wherein the electrochemical treatment unit includes a cavity, electrodes respectively arranged at both ends of the cavity, a power supply connecting the electrodes at both ends, and an anion exchange membrane is used to separate the cavity into a first chamber and a second chamber. The cathode and anode flow electrode slurries circulate in the second and first chambers respectively. After a constant current or voltage is applied to the electrodes by the power supply, the lithium-poor material in the cathode flow electrode slurry selectively adsorbs the lithium ions in the lithium-containing stock solution to form a lithium-rich material, and the lithium-rich material in the anode flow electrode slurry desorbs the lithium ions to form a lithium-poor material, and the lithium ions are released into the anode slurry. Then, the slurry is separated into solid and liquid and washed. The lithium-rich material after the original cathode adsorption is saturated is used as the anode material of the next batch of electrochemical lithium extraction process to remove lithium, and the lithium-poor material after the original anode desorption is used as the cathode material of the next batch of electrochemical lithium extraction process to absorb lithium. This cycle is repeated several times, and the lithium concentration in the anode slurry is continuously enriched.

[0003] However, the slurry involved in this system contains electrochemically active substances and conductive agents. The particle size of these substances is relatively fine, which makes the slurry present a large viscosity, and it is easy to agglomerate and adhere and deposit on the surface of the plate flow channel, resulting in a reduction in the cross-sectional area of ​​the flow channel, an increase in the energy consumption of the circulating pump, and an inability to operate for a long time. Chinese patent applications 202410399194.0 and 202410447358.2 disclose two structural forms of electrochemical lithium extraction plates. The plate is designed with flow channels to increase the contact area between the slurry and the plate. The slurry is evenly distributed in each flow channel through reasonable liquid distribution, eliminating the dead corners of the slurry flow, and improving the efficiency of lithium ion insertion and removal. However, due to the strong adhesion of the slurry on the surface of the plate flow channel, the adhesion phenomenon can be alleviated by reasonable design of the plate flow channel form and increasing the flow rate of the slurry on the flow channel surface, but it will increase additional power consumption. Other measures, such as increasing the flow rate of the slurry on the flow channel surface for a short time to flush the adhesion parts, and regularly switching the flow direction of the slurry in the plate flow channel, cannot completely remove the slurry adhering to the plate flow channel. In addition, after a long period of operation, a passivation layer will form on the surface of the plate flow channel, reducing the lithium extraction efficiency of the device.

[0004] Therefore, there is an urgent need to develop a cleaning system and method to solve the problem of slurry blocking the flow channel and electrode surface passivation during the operation of the electrochemical lithium extraction device. Summary of the invention

[0005] The technical problem to be solved by the present invention is that the electrode slurry adheres during the circulation process, blocking the plate flow channel, causing the equipment to be unable to operate for a long time, and the surface of the electrode flow channel is passivated, resulting in a decrease in the lithium extraction efficiency of the device. The purpose of the present invention is to provide a plate cleaning system and method for a flowing slurry electrochemical lithium extraction device. The method is a plate cleaning method with low energy consumption, easy operation and good effect. The purpose of the present invention is achieved through the following specific technical solutions.

[0006] A plate cleaning system for a flowing slurry electrochemical lithium extraction device comprises: a circulating water washing unit, comprising a cathode cleaning water tank, a cathode cleaning water pump, an anode cleaning water tank, an anode cleaning water pump and a power supply, wherein the cathode cleaning water tank outlet is connected to the cathode chamber inlet of the electrochemical lithium extraction device through the cathode cleaning water pump, and the cathode chamber outlet of the electrochemical lithium extraction device is connected to the cathode cleaning water tank inlet, wherein the anode cleaning water tank outlet is connected to the anode chamber inlet of the electrochemical lithium extraction device through the anode cleaning water pump, and the anode chamber outlet of the electrochemical lithium extraction device is connected to the anode cleaning water tank inlet; one end of the power supply is connected to the cathode, and the other end is connected to the anode; the cathode is arranged on the cathode chamber of the electrochemical lithium extraction device; the anode is arranged on the anode chamber of the electrochemical lithium extraction device;

[0007] The dosing cleaning unit comprises a dosing cleaning water storage tank, a dosing cleaning water pump, a reagent storage tank, a dosing pump and an online pH meter, wherein the outlet of the dosing cleaning water storage tank is respectively connected to the cathode chamber inlet and the anode chamber inlet of the electrochemical lithium extraction device through the dosing cleaning water pump, the cathode chamber outlet and the anode chamber outlet of the electrochemical lithium extraction device are connected to the inlet of the dosing cleaning water storage tank, wherein the outlet of the reagent storage tank is connected to the dosing cleaning water storage tank through the dosing pump, and an online pH meter is arranged in the dosing cleaning water storage tank.

[0008] A method for cleaning the plate of a flowing slurry electrochemical lithium extraction device, using the above-mentioned plate cleaning system of the flowing slurry electrochemical lithium extraction device, the method comprising:

[0009] Step 1 is a separate water washing, that is, when the electrochemical lithium extraction device completes a cycle of lithium electrolysis and deintercalation, the cleaning water in the cathode and anode cleaning water tanks is respectively sent to the cathode chamber and the anode chamber, and the cleaning water circulates rapidly in the cleaning water tank and the cathode chamber and the anode chamber to flush the cathode plate flow channel surface and the anode plate flow channel surface;

[0010] Step 2 is power-on water washing, that is, during the circulation of washing water, a constant forward voltage is applied to the cathode and anode of the electrochemical lithium extraction device to precipitate gas on the electrode surface, and after powering on for a period of time, the power supply is reversed, and a constant reverse voltage is continued to be applied, and the power is turned off after powering on for a period of time;

[0011] Step three is chemical cleaning, that is, chemical cleaning is performed on the cathode plate flow channel surface and the anode plate flow channel surface of the electrochemical lithium extraction device, and the chemical cleaning water in the chemical cleaning water storage tank is respectively sent to the cathode chamber and the anode chamber. The chemical cleaning water circulates in the chemical cleaning water storage tank and the cathode chamber and the anode chamber to clean the cathode plate flow channel surface and the anode plate flow channel surface.

[0012] Furthermore, in step 1, the cathode cleaning water is a sodium sulfate solution, the mass concentration of sodium sulfate is 0.1%-0.5%, and the pH is adjusted to 1-6.5. For example, the mass concentration of sodium sulfate in the cathode cleaning water is 0.1%, 0.15%, 0.2%, 0.3%, 0.4% or 0.5%.

[0013] Furthermore, in step 1, the anode cleaning water is a sodium sulfate solution, and the mass concentration of sodium sulfate is 0.5%-10%. For example, the mass concentration of sodium sulfate in the anode cleaning water is 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 6%, 8% or 10%.

[0014] Furthermore, in step 1, the flushing flow rate of the washing water on the surface of the flow channel of the cathode and anode plates is 0.5-1.0 m / s. For example, in step 1, the flushing flow rate of the washing water on the surface of the flow channel of the cathode and anode plates is 0.5 m / s, 0.6 m / s, 0.7 m / s, 0.8 m / s, 0.9 m / s or 1.0 m / s.

[0015] Furthermore, in step 1, the cleaning time is 1-5 minutes.

[0016] Furthermore, in step 2, the voltage range is 1.3-2.5V. For example, the voltage is 1.3V, 1.5V, 1.8V or 2.5V.

[0017] Furthermore, in step 2, the flushing flow rate of the washing water on the cathode plate flow channel surface and the anode plate flow channel surface is 0.1-0.5 m / s. For example, in step 2, the flushing flow rate of the washing water on the cathode plate flow channel surface and the anode plate flow channel surface is 0.1 m / s, 0.2 m / s, 0.3 m / s or 0.5 m / s.

[0018] Furthermore, in step 2, the total cleaning time is 20-60 minutes, of which the forward power cleaning time is 10-30 minutes and the reverse power cleaning time is 10-30 minutes.

[0019] Furthermore, in step three, the medicated cleaning water is one, two or three of aqueous solutions of hydrochloric acid, sulfuric acid and citric acid.

[0020] Furthermore, in step three, the pH range of the medicated cleaning water is 1-3.

[0021] Furthermore, in step three, the flushing flow rate of the added cleaning water on the cathode plate flow channel surface and the anode plate flow channel surface is 0.1-0.5m / s.

[0022] Furthermore, in step three, the total time for adding chemicals and cleaning is 20-60 minutes.

[0023] The technical solution of the present invention has the following advantages:

[0024] 1. The present invention provides a plate cleaning system for an electrochemical lithium extraction device with a simple composition. The system can utilize the existing cathode slurry circulation pump, anode slurry circulation pump and power supply in the electrochemical lithium extraction device as the cathode cleaning water pump, anode cleaning water pump and power supply of the cleaning system, respectively.

[0025] 2. The present invention provides a method for cleaning the plates of a flowing slurry electrochemical lithium extraction device, which passes cleaning water through the surface of the plate flow channel at a specific flow rate and causes the water to electrolyze under the action of an external voltage. This process produces gases such as oxygen on the electrode surface, which effectively peels off and removes the sediments adhering to the surface of the plate flow channel. There is no residue on the surface of the plate after cleaning, ensuring the thoroughness of the cleaning. This method is not only easy to operate, but also has a short cleaning time. Compared with the high-flow rate flushing method, it has lower energy consumption and better cleaning effect.

[0026] 3. The present invention provides a method for cleaning the plates of a flowing slurry electrochemical lithium extraction device, which utilizes medicated cleaning water to circulate and clean the surface of the plate flow channel, and can effectively remove the passivation layer on the surface of the plate flow channel, thereby restoring the electrochemical properties of the plate surface. The method is simple to operate and has good effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The present invention is a schematic diagram of the structure of the plate cleaning system of a flowing slurry electrochemical lithium extraction device.

[0028] Figure numerals: 1-cathode cleaning water tank, 2-cathode cleaning water pump, 3-anode cleaning water tank, 4-anode cleaning water pump, 5-cathode chamber, 6-anode chamber, 7-anion exchange membrane, 8-power supply, 9-dosing cleaning water pump, 10-dosing cleaning water storage tank, 11-dosing pump, 12-drug storage tank. DETAILED DESCRIPTION

[0029] It should be understood that in the description of the present disclosure, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present disclosure. In addition, the terms "first", "second", etc., are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of such features.

[0030] It should be noted that in the description of the present disclosure, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present disclosure can be understood according to specific circumstances.

[0031] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0032] Example 1

[0033] A plate cleaning system for a flowing slurry electrochemical lithium extraction device, such as Figure 1 As shown, it includes: a circulating water washing unit, including a cathode washing water tank 1, a cathode washing water pump 2, an anode washing water tank 3, an anode washing water pump 4 and a power supply 8. The anion exchange membrane 7 divides the internal space of the flowing slurry electrochemical lithium extraction device into a cathode chamber 5 and an anode chamber 6. One end of the power supply 8 is connected to the cathode on the cathode chamber 5 of the electrochemical lithium extraction device, and the other end is connected to the anode on the anode chamber 6 of the electrochemical lithium extraction device. The outlet of the cathode cleaning water tank 1 is connected to the inlet of the cathode chamber 5 of the electrochemical lithium extraction device through the cathode cleaning water pump 2, and the outlet of the cathode chamber of the electrochemical lithium extraction device is connected to the inlet of the cathode cleaning water tank 1, wherein the outlet of the anode cleaning water tank 3 is connected to the inlet of the anode chamber 6 of the electrochemical lithium extraction device through the anode cleaning water pump 4, and the outlet of the anode chamber of the electrochemical lithium extraction device is connected to the inlet of the anode cleaning water tank 3; the dosing cleaning unit includes a dosing cleaning water storage tank 10, a dosing cleaning water pump 9, a reagent storage tank 12, a dosing pump 11 and an online pH meter, wherein the outlet of the dosing cleaning water storage tank 10 is respectively connected to the inlet of the cathode chamber 5 and the inlet of the anode chamber 6 of the electrochemical lithium extraction device through the dosing cleaning water pump 9, and the outlet of the cathode chamber 5 and the anode chamber 6 of the electrochemical lithium extraction device are both connected to the inlet of the dosing cleaning water storage tank 10, wherein the outlet of the reagent storage tank 12 is connected to the dosing cleaning water storage tank 10 through the dosing pump 11, and an online pH meter is arranged in the dosing cleaning water storage tank 10.

[0034] A method for cleaning the plate of a flowing slurry electrochemical lithium extraction device using the above-mentioned plate cleaning system comprises:

[0035] Step 1: Send the cleaning water in the cathode cleaning water tank 1 and the anode cleaning water tank 3 into the cathode chamber 5 and the anode chamber 6 respectively. The cleaning water circulates in the cathode cleaning water tank 1 and the cathode chamber 5 to flush the surface of the cathode plate flow channel, and the cleaning water circulates in the anode cleaning water tank 3 and the anode chamber 6 to flush the surface of the anode plate flow channel. Specifically, the cathode cleaning water is a 0.2wt% sodium sulfate aqueous solution with a pH of 2, and the anode cleaning water is a 5wt% sodium sulfate aqueous solution. The flow rate of the cleaning water on the surface of the cathode / anode plate flow channel is 0.5m / s, and the cleaning time is 5min;

[0036] Step 2: Apply a constant forward voltage of 1.3V to the cathode and anode of the electrochemical lithium extraction device to precipitate oxygen on the anode surface. The flow rate of the cleaning water on the surface of the cathode / anode plate flow channel is 0.2m / s. The power is turned on for cleaning for 30 minutes, and then the power supply is reversed, and a constant reverse voltage of 1.9V is continued to be applied, and the power is turned on for cleaning for 30 minutes;

[0037] Step 3: Add chemicals to clean the cathode plate flow channel surface and the anode plate flow channel surface of the electrochemical lithium extraction device. Add tap water and hydrochloric acid to the chemical cleaning water storage tank 10, adjust the pH to 1.8, and send the hydrochloric acid solution in the chemical cleaning water storage tank to the cathode chamber 5 and the anode chamber 6 respectively. The hydrochloric acid solution circulates in the chemical cleaning water storage tank 10 and the cathode chamber 5 and the anode chamber 6. The flushing flow rate on the cathode / anode plate flow channel surface is 0.25m / s, and the chemical cleaning time is 50min.

[0038] Example 2

[0039] The difference between this embodiment and embodiment 1 is that the parameter conditions are different. Specifically, in this embodiment, the cathode cleaning water is a 0.1wt% sodium sulfate aqueous solution with a pH of 3, and the anode cleaning water is a 1wt% sodium sulfate solution. The flow rate of the cleaning water on the surface of the plate flow channel is 0.8m / s, and the cleaning time is 3min. When powered on for cleaning, the flow rate of the cleaning water on the surface of the cathode / anode plate flow channel is 0.3m / s, the forward voltage applied is 1.9V, and the cleaning time is 20min. After the inversion, the reverse voltage applied is 1.9V, and the cleaning time is 20min. When adding chemicals for cleaning, a sulfuric acid aqueous solution with a pH of 2 is used, and the flushing flow rate on the surface of the cathode / anode plate flow channel is 0.4m / s, and the cleaning time for adding chemicals is 30min.

[0040] Example 3

[0041] The difference between this embodiment and embodiment 1 is that the parameter conditions are different. Specifically, in this embodiment, the cathode cleaning water is a 0.3wt% sodium sulfate aqueous solution with a pH of 4, and the anode cleaning water is a 10wt% sodium sulfate solution. The flow rate of the cleaning water on the surface of the cathode / anode plate flow channel is 1.0m / s, and the cleaning time is 1min. When powered on for cleaning, the flow rate of the cleaning water on the surface of the cathode / anode plate flow channel is 0.4m / s, the forward voltage applied is 1.3V, and the cleaning time is 30min. The reverse voltage applied after the inversion is 1.9V, and the cleaning time is 20min. When adding a citric acid aqueous solution with a pH of 2 is used for cleaning, the flushing flow rate on the surface of the cathode / anode plate flow channel is 0.3m / s, and the cleaning time for adding a citric acid aqueous solution is 45min.

[0042] Example 4

[0043] The difference between this embodiment and embodiment 1 is that the parameter conditions are different. Specifically, in this embodiment, the cathode cleaning water is a 0.4wt% sodium sulfate aqueous solution with a pH of 5, and the anode cleaning water is an 8wt% sodium sulfate solution. The flow rate of the cleaning water on the surface of the cathode / anode plate flow channel is 0.6m / s, and the cleaning time is 4min. When powered on for cleaning, the flow rate of the cleaning water on the surface of the cathode / anode plate flow channel is 0.1m / s, the forward voltage applied is 2.0V, and the cleaning time is 10min. The reverse voltage applied after the inversion is 2.5V, and the cleaning time is 10min. When adding a drug for cleaning, a hydrochloric acid aqueous solution with a pH of 2 is used, and the flushing flow rate on the surface of the cathode / anode plate flow channel is 0.1m / s, and the adding a drug for cleaning is 60min.

[0044] Example 5

[0045] The difference between this embodiment and embodiment 1 is that the parameter conditions are different. Specifically, in this embodiment, the cathode cleaning water is a 0.5wt% sodium sulfate aqueous solution with a pH of 3, and the anode cleaning water is a 3wt% sodium sulfate solution. The flow rate of the cleaning water on the surface of the cathode / anode plate flow channel is 1.0m / s, and the cleaning time is 1min. When powered on for cleaning, the flow rate of the cleaning water on the surface of the cathode / anode plate flow channel is 0.2m / s, the forward voltage applied is 1.4V, and the cleaning time is 20min. The reverse voltage applied after the inversion is 2.5V, and the cleaning time is 10min. When adding chemicals for cleaning, a sulfuric acid aqueous solution with a pH of 2 is used, and the flushing flow rate on the surface of the cathode / anode plate flow channel is 0.2m / s, and the adding chemicals for cleaning is 50min.

[0046] In the embodiments shown in Examples 2-5 of the present invention described above, the effects substantially equivalent to those in Example 1 can be effectively achieved, and the slurry adhered and deposited on the surface of the plate flow channel can be completely removed, as well as the passivation layer on the surface of the plate flow channel. Obviously, the above embodiments are merely examples for clear explanation, and are not limitations on the implementation methods. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made on the basis of the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A method for cleaning the plate of a flowing slurry electrochemical lithium extraction device, characterized in that: A plate cleaning system for a flowing slurry electrochemical lithium extraction device is used, the cleaning system comprising: A circulating water washing unit comprises a cathode washing water tank (1), a cathode washing water pump (2), an anode washing water tank (3), an anode washing water pump (4) and a power supply (8), wherein the outlet of the cathode washing water tank (1) is connected to the inlet of the cathode chamber (5) of the electrochemical lithium extraction device through the cathode washing water pump (2), the outlet of the cathode chamber (5) of the electrochemical lithium extraction device is connected to the inlet of the cathode washing water tank (1), wherein the outlet of the anode washing water tank (3) is connected to the inlet of the anode chamber (6) of the electrochemical lithium extraction device through the anode washing water pump (4), the outlet of the anode chamber (6) of the electrochemical lithium extraction device is connected to the inlet of the anode washing water tank (3); one end of the power supply (8) is connected to the cathode, and the other end is connected to the anode; the cathode is arranged on the cathode chamber (5) of the electrochemical lithium extraction device; the anode is arranged on the anode chamber (6) of the electrochemical lithium extraction device; A dosing cleaning unit comprises a dosing cleaning water storage tank (10), a dosing cleaning water pump (9), a reagent storage tank (12), a dosing pump (11) and an online pH meter, wherein the outlet of the dosing cleaning water storage tank (10) is respectively connected to the inlet of the cathode chamber (5) and the inlet of the anode chamber (6) of the electrochemical lithium extraction device through the dosing cleaning water pump (9), the outlet of the cathode chamber (5) and the outlet of the anode chamber (6) of the electrochemical lithium extraction device are connected to the inlet of the dosing cleaning water storage tank (10), wherein the outlet of the reagent storage tank (12) is connected to the dosing cleaning water storage tank (10) through the dosing pump (11), and an online pH meter is arranged in the dosing cleaning water storage tank (10); The method comprises: Step 1 is a separate water washing, that is, after the electrochemical lithium extraction device completes a cycle of the lithium electrolysis and deintercalation process, the cleaning water in the cathode and anode cleaning water tanks (3) is respectively sent to the cathode chamber (5) and the anode chamber (6), and the cleaning water circulates in the cleaning water tank and the cathode chamber (5) and the anode chamber (6) to flush the cathode plate flow channel surface and the anode plate flow channel surface; Step 2 is power-on water washing, that is, during the circulation of washing water, a constant forward voltage is applied to the cathode and anode of the electrochemical lithium extraction device to precipitate gas on the electrode surface. After the power is turned on for a predetermined time, the power supply is reversed and a constant reverse voltage is continued to be applied. After the power is turned on for a predetermined time, the power is turned off; Step three is chemical cleaning, i.e., chemical cleaning is performed on the surfaces of the cathode and anode plate flow channels of the electrochemical lithium extraction device, and the chemical cleaning water in the chemical cleaning water storage tank (10) is respectively sent to the cathode chamber (5) and the anode chamber (6), and the chemical cleaning water circulates in the chemical cleaning water storage tank and the cathode chamber (5) and the anode chamber (6) to clean the cathode plate flow channel surfaces and the anode plate flow channel surfaces; In step 1, the cathode cleaning water is a sodium sulfate solution, the mass concentration of sodium sulfate is 0.15%-0.5%, and the pH is adjusted to 1-6.5; In step 1, the anode cleaning water is a sodium sulfate solution with a mass concentration of sodium sulfate of 0.5%-8%; In step 1, the flushing flow rate of the cleaning water on the cathode plate flow channel surface and the anode plate flow channel surface is 0.5-1.0 m / s; The cleaning time is 1-5min; in step 2, the flushing flow rate of the cleaning water on the cathode plate flow channel surface and the anode plate flow channel surface is 0.1-0.5m / s; in step 2, the total cleaning time is 20-60min, of which the forward power cleaning time is 10-30min, and the reverse power cleaning time is 10-30min; in step 3, the pH range of the dosing cleaning water is greater than or equal to 1 and less than 3; in step 3, the flushing flow rate of the dosing cleaning water on the cathode plate flow channel surface and the anode plate flow channel surface is 0.1-0.5m / s; in step 3, the total dosing cleaning time is 20-60min.

2. The method according to claim 1, characterized in that In step 2, the voltage range is 1.3-2.5V.

3. The method according to claim 1, characterized in that In step 3, the cleaning water is one or a mixture of aqueous solutions of hydrochloric acid, sulfuric acid, and citric acid.

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