A regeneration and circulation system of TFT-LCD copper etching solution

Abstract

The utility model relates to a kind of regeneration circulation system of TFT-LCD copper etching liquid, belong to liquid crystal display manufacturing waste liquid processing technical field.The system includes extraction cylinder, washing cylinder, circulation cylinder, back extraction cylinder and electrolytic system, and copper etching waste liquid is separated into water phase and oil phase by extraction cylinder;Water phase is supplemented with hydrogen peroxide or untreated etching liquid by circulation cylinder to obtain regenerated etching liquid;Oil phase is treated by washing cylinder to obtain purified oil phase and return extraction cylinder for recycling, while obtaining metal concentrate;Metal concentrate is mixed with acid liquid in back extraction cylinder and enters electrolytic system to produce cathode copper by electrolysis.The system uses double-way regeneration treatment process, washing cylinder is designed with overflow partition to separate first and second washing units, and back extraction cylinder bottom is conical structure and equipped with ultrasonic anti-crystallization device.The utility model realizes efficient recycling of copper etching waste liquid, reduces waste liquid treatment cost and reduces environmental pollution.

Description

Technical Field

[0001] This invention relates to the field of waste liquid resource utilization technology, and more specifically, to a regeneration and recycling system for TFT-LCD copper etching solution. Background Technology

[0002] With the rapid development of the TFT-LCD (Thin Film Transistor Liquid Crystal Display) industry, the treatment and regeneration of copper-containing etching wastewater generated during its manufacturing process has become increasingly prominent. Copper etching is a critical process step in TFT-LCD manufacturing, typically using an etching solution containing hydrogen peroxide to pattern the copper layer. However, as the etching process progresses, the concentration of copper ions in the etching solution continuously increases, leading to a decrease in etching efficiency and causing environmental pollution and resource waste.

[0003] Currently, various technical solutions exist in the industry for the treatment and regeneration of copper-containing etching wastewater. For example, Chinese patent application CN105506636A discloses a recycling system and method for extracting copper-containing wastewater. This system includes an extraction device, a washing device, a circulation device, a back-extraction device, and an electrolysis device. It improves the copper extraction rate through a dual washing process and incorporates a stirring separation chamber to enhance separation efficiency. Chinese patent application CN110144590A proposes a regeneration system for alkaline copper-containing etching wastewater and ammonia nitrogen wastewater recycling. This system achieves copper recovery and ammonia nitrogen wastewater recycling by mixing alkaline copper-containing etching wastewater with an extractant. Chinese patent application CN211339693U also discloses a system for regenerating alkaline copper-containing etching waste liquid and recycling ammonia nitrogen wastewater, including an extraction device, a washing device, a back-extraction device, and an electrolysis device, which can efficiently recover copper from alkaline copper-containing etching waste liquid. In addition, Chinese patent application CN205529043U describes a recycling system for extracting copper-containing waste liquid. This system improves the copper extraction rate through a double washing process and improves the separation efficiency by setting up a stirring separation chamber, realizing the recycling of etching liquid and residual liquid. Chinese patent CN114606497B discloses a process for treating and recycling ferric chloride etching liquid. This method does not introduce any oxidant, which can greatly reduce costs, and does not generate chlorine gas during electrolysis, thus avoiding safety hazards. However, existing extraction systems often lack targeted design when treating specific copper etching liquids for TFT-LCDs, and cannot effectively solve the safety hazard of hydrogen peroxide self-decomposition. At the same time, existing systems have shortcomings in the design of the washing stage, making it difficult to achieve efficient oil phase purification and separation of metal concentrates. In addition, the existing back-extraction device has an unreasonable structural design, which is prone to crystallization blockage and affects the long-term stable operation of the system.

[0004] Chinese utility model patent CN205529043U discloses a recycling system for extracting copper-containing waste liquid. This system has the following technical limitations: it only connects the circulation tank and the extraction tank via simple pipes, without a copper ion concentration monitoring mechanism. Furthermore, during the regeneration process, when residual copper ions exceed 500 ppm, the etching solution catalyzes the violent decomposition of hydrogen peroxide, posing an explosion hazard. Additionally, while the patent employs a dual-washing process, it relies on static RO membrane filtration, which cannot effectively treat colloidal metal particles. This results in a reduced number of extractant cycles and a high residual copper content in the oil phase. Although it uses a multi-stage back-extraction sub-tank design to delay crystallization, it does not address the fundamental problem, easily causing acid copper crystals to clog the pipes, requiring frequent shutdowns for maintenance. Moreover, the passive residual liquid reflux cannot inhibit crystal growth.

[0005] Furthermore, existing technologies still present several challenges in regenerating and recycling copper etching solutions for TFT-LCDs: Firstly, with the increasing size of TFT-LCDs, the amount of etching solution used in wet etching is growing significantly, substantially increasing manufacturing costs. Secondly, mainstream etching solutions contain hydrogen peroxide, and as etching progresses, the increasing copper ion concentration catalyzes the self-decomposition of hydrogen peroxide, posing a potential explosion risk. Thirdly, the increased copper ion concentration in the etching solution leads to poor etching characteristics, affecting product quality. Additionally, existing methods for increasing etching lifespan by adding etching additives or auxiliaries require continuous replenishment, increasing process complexity and operational difficulty.

[0006] Therefore, there is an urgent need to develop a regeneration and recycling system specifically for TFT-LCD copper etching solution, which can effectively solve the above-mentioned technical problems, achieve efficient regeneration and recycling of etching solution, reduce manufacturing costs, eliminate safety hazards, and maintain good etching characteristics. Utility Model Content

[0007] One of the technical problems to be solved by this utility model is to provide a TFT-LCD copper etching solution regeneration and recycling system to overcome the technical problems existing in the prior art, such as short service life of etching solution, safety hazards caused by the accumulation of copper ions catalyzing the decomposition of hydrogen peroxide, decreased etching characteristics, low recycling efficiency, and discontinuous process. This system aims to achieve efficient regeneration of etching solution, recycling of metal resources, and long-term stability and economy of system operation.

[0008] To overcome the shortcomings of the prior art, this utility model provides a TFT-LCD copper etching solution regeneration and recycling system, comprising: an extraction device, a water washing device, a circulation device, a back-extraction device, and an electrolysis device, wherein:

[0009] The extraction device is connected to an external waste liquid discharge port, and the extraction device is equipped with an aqueous phase outlet, an oil phase outlet, an active reflux inlet, and a purification extractant inlet.

[0010] The inlet of the circulation device is connected to the aqueous phase outlet, and the outlet of the circulation device is connected to the active reflux inlet. The circulation device (3) is equipped with a copper ion concentration sensor (31), and the copper ion concentration sensor (31) is communicatively connected to the control system. The circulation device (3) is also equipped with a regenerated liquid replenishment device (32), and the regenerated liquid replenishment device (32) is equipped with an electromagnetic valve (321), and the electromagnetic valve (321) is communicatively connected to the control system. The regenerated liquid replenishment device (32) is used to replenish hydrogen peroxide or untreated etching solution into the circulation device (3).

[0011] The inlet of the water washing device is connected to the oil phase outlet, and the water washing device is provided with a concentrated metal liquid outlet and a purification extractant outlet. The purification regeneration liquid outlet is connected to the purification extractant inlet, and a microwave radiator (24) is provided inside the water washing device (2).

[0012] The inlet of the back-extraction device is connected to the outlet of the concentrated metal liquid, and the outlet of the back-extraction device is connected to the electrolysis device.

[0013] The working process of this TFT-LCD copper etching solution regeneration and recycling system is as follows:

[0014] Copper-containing etching wastewater is fed into the extraction device through the wastewater discharge port. Under the action of the extractant, it undergoes mixing and mass transfer to separate into an aqueous phase and an oil phase. The aqueous phase is transported to the circulation device through the aqueous phase outlet. In the circulation device, hydrogen peroxide or untreated etching solution is added in conjunction with a copper ion concentration sensor and a regeneration solution replenishment device to obtain regenerated etching solution. The regenerated etching solution is returned to the extraction device through the active reflux inlet. The copper ion concentration sensor detects the copper ion concentration in the liquid in the circulation device in real time, and then sends the signal to the control system. The control system opens the solenoid valve according to the concentration, thereby replenishing hydrogen peroxide or untreated etching solution to the circulation device. The oil phase is transported to the water washing device through the oil phase outlet. The process involves water washing to obtain a purified oil phase and a metal concentrate. A microwave radiator in the water washing unit applies microwave radiation to the semi-finished oil phase, promoting the aggregation of metal particles. The resulting concentrate, after being concentrated by a hydrocyclone separator, is then fed into the back-extraction tank. The purified oil phase is transported from the purified extractant outlet to the purified extractant inlet and then into the extraction unit for further processing. The metal concentrate is transported from the concentrated metal liquid outlet to the back-extraction unit. In the back-extraction unit, the metal concentrate is mixed with acid solution for back-extraction to obtain a copper-rich solution. This copper-rich solution is then fed into an electrolysis unit for electrolysis, producing cathode copper and completing the process. The regenerated acid solution generated after electrolysis is fed from the acid inlet to the back-extraction unit through the regenerated acid outlet, thus achieving acid recycling.

[0015] Compared with existing technologies, the TFT-LCD copper etching solution regeneration and recycling system of this application adopts a unique dual-path processing system: on the one hand, the aqueous phase is regenerated through a circulation device and then returned to the system to extend the service life of the etching solution; on the other hand, the oil phase is purified by multi-stage water washing to obtain a purified extractant and settle metal concentrate, which then enters the back-extraction and electrolysis process to finally recover usable cathode copper. Compared with existing technologies, this invention has the following significant advantages:

[0016] The extraction-separation-reflux linkage design enhances system regeneration efficiency: By regenerating the aqueous and oil phases separately and adding hydrogen peroxide or fresh etching solution to the circulation device, etching capacity is effectively restored, significantly extending the service life of the etching solution; a water washing system enhances the oil phase purification capacity, achieving efficient removal of oil phase impurities; the back-extraction device guides the concentrated discharge of the enriched solution through physical structure, improving continuous operation capability; the electrolysis device produces cathode copper through electrolysis of the enriched solution, while simultaneously achieving closed-loop acid circulation, reducing chemical consumption; good adaptability and scalability: This system is suitable for treating multi-metal etching waste liquid, and by adjusting the extractant ratio and treatment process, the separation and recovery of copper, molybdenum, and other metals can be further achieved; the TFT-LCD copper etching solution regeneration and circulation system provided by this utility model combines multiple functional units such as liquid phase extraction, water washing purification, back-extraction enrichment, and electrolytic recovery. Through the synergistic effect of flow path control and structural optimization, it achieves efficient regeneration of etching solution and maximizes the recovery of copper resources, demonstrating outstanding economic benefits, safety performance, and promising industrial application prospects.

[0017] In one possible implementation, the electrolysis device is further provided with a regenerated acid outlet, and the regenerated acid outlet is connected to the acid inlet provided on the back-extraction device.

[0018] Compared with existing technologies, the above technical solution achieves the recycling of acid resources by sealing and recirculating the residual acid (regenerated acid) generated by the electrolysis unit back to the stripping unit, replacing the traditional method of continuously adding new acid. By utilizing the acidic components that are not exhausted during the electrolysis process to continue to participate in the metal stripping process, not only is acid waste avoided, but the frequency of acid replacement is also reduced.

[0019] In one possible implementation, the concentrated metal liquid outlet is located at the bottom of the washing device, the purification extractant outlet is located on the side of the washing device, and the microwave radiator is located at the bottom of the second washing unit.

[0020] Compared with existing technologies, the above-mentioned technical solution achieves efficient separation of metal concentrates during the water washing process based on the principle of gravity sedimentation. Cross-contamination is avoided by rationally arranging the liquid flow outlet path. Metal impurities naturally settle to the bottom of the device during water washing and are discharged from the bottom of the concentrate, effectively reducing entrainment. The purified oil phase is output from the side, ensuring high purity of the oil phase. The microwave radiator at the bottom of the second water washing unit can apply microwave radiation to the semi-finished oil phase, promoting the aggregation of metal particles. The concentrated liquid after separation is then concentrated by the hydrocyclone separator and fed into the back-extraction tank, further improving the technical effect.

[0021] In one possible implementation, the washing device includes a primary washing unit and a secondary washing unit separated by a liquid flow transfer component. The inlet of the primary washing unit is connected to the oil phase outlet. Both the primary and secondary washing units have concentrated metal liquid outlets at their bottoms, and the purification extractant outlet is located on the side of the secondary washing unit.

[0022] Compared with existing technologies, the above technical solution forms a two-stage continuous water washing process through the liquid flow transfer component, which sequentially completes primary and deep purification, improves the purification efficiency of the oil phase, and the overflow structure can realize automatic liquid stratification and transfer, allowing the oil phase to enter multiple cleaning zones in sequence, significantly reducing the concentration of impurities and improving the metal concentration efficiency.

[0023] In one possible implementation, the liquid flow transfer component is an overflow baffle, which is disposed between the first water washing unit and the second water washing unit, and the top of the baffle is 200-300mm lower than the top surface of the first water washing unit, thereby forming an overflow channel; the concentrated metal liquid outlet at the bottom of the second water washing unit is connected to the back-extraction device through a hydrocyclone separator.

[0024] Compared with existing technologies, the above-mentioned technical solution allows the overflow baffle to allow the oil phase in the first water washing unit to flow naturally into the second water washing unit after reaching a certain liquid level, avoiding turbulence and liquid level fluctuations caused by mechanical or pumped transfer. By utilizing the liquid level difference and gravitational potential energy to form a stable liquid transition, the oil phase is ensured to overflow in a smooth manner, thereby guaranteeing the graded cleaning effect of the water washing process. Through the linkage of the above-mentioned hydrocyclone separator and microwave radiator, microwave radiation can be applied to the semi-finished oil phase in the second water washing unit during the reaction process to promote the aggregation of metal particles. The concentrated liquid after separation is concentrated by the hydrocyclone separator and then fed into the back-extraction tank, breaking through the bottleneck of traditional gravity sedimentation efficiency and increasing the concentration of metal concentrate.

[0025] An anti-siphon U-shaped pipe is provided between the outlets of the concentrated metal liquid, and the height of the anti-siphon U-shaped pipe is ≥300mm.

[0026] Compared with existing technologies, the above technical solution can effectively prevent backflow and cross-contamination between different liquids caused by pipeline pressure difference or operational errors. The U-shaped tube structure forms a physical liquid seal, which avoids uncontrolled backflow of liquid due to siphon effect when the system is interrupted or stopped, thereby enhancing the controllability of liquid diversion and the safety of the system, and preventing pollution or abnormal liquid level from affecting subsequent processing procedures.

[0027] In one possible implementation, a backflow prevention check valve is provided between the purification extractant outlet and the purification extractant inlet.

[0028] Compared with existing technologies, the above technical solution can prevent liquid or impurities in the extraction device from flowing back to the washing device, avoid cross-contamination or system imbalance, and allow the purified extractant to flow only in a predetermined direction through the physical structure of the one-way valve, thereby establishing a stable circulation path, which in turn ensures the correct flow direction and cleanliness of the extractant circulation process, improves the system recycling efficiency and enhances operational reliability.

[0029] In one possible implementation, the bottom of the back-extraction device is a conical structure with a cone angle of 60-90°, the lowest point of the conical structure is the outlet of the back-extraction device, and the bottom of the back-extraction device is provided with an ultrasonic anti-crystallization device.

[0030] Compared with existing technologies, the above-mentioned technical solution promotes the concentrated discharge of heavy metal deposits during the back-extraction process, while suppressing the risk of deposition crystallization blockage. This embodiment utilizes the gravity guidance of the conical structure and minimizes the retention space, so that the precipitate is naturally concentrated to the bottom outlet; combined with ultrasonic oscillation, it effectively breaks the crystal formation process and avoids the deposition of metal salts at the bottom of the device.

[0031] The principle and process of the system in this invention for diverting and regenerating waste liquid are as follows:

[0032] S1: Extraction process:

[0033] Copper-containing etching waste liquid is fed into the extraction device through the waste liquid discharge port. Under the action of the extractant, it undergoes mixing and mass transfer to separate the aqueous phase and the oil phase.

[0034] S2: Dual-path regeneration processing:

[0035] Aqueous phase treatment: The aqueous phase is transported from the aqueous phase outlet of the extraction device to the circulation device, and hydrogen peroxide or untreated etching solution is added to obtain regenerated etching solution;

[0036] Oil phase treatment: The oil phase is sent from the oil phase outlet of the extraction device to the water washing device for water washing treatment to obtain a purified oil phase and metal concentrate. The purified oil phase is sent from the purified extractant outlet to the purified extractant inlet to the extraction device for processing. The metal concentrate is sent from the concentrated metal liquid outlet to the back-extraction device.

[0037] S3: Electrolytic copper removal from metals:

[0038] In the back-extraction unit, the metal concentrate is mixed with acid solution for back-extraction to obtain a copper-rich solution. Then, the copper-rich solution is passed into an electrolysis unit for electrolysis to produce cathode copper, thus completing the process.

[0039] This invention's regeneration and recycling system optimizes the traditional direct waste liquid copper recovery process into a "dual-path split regeneration" method of aqueous phase regeneration + oil phase copper extraction. This avoids the runaway reaction and resource waste caused by the continuous reaction between copper ions and the etching agent. In the extraction step, copper ions are selectively separated, allowing the aqueous phase of the etching solution to be used for replenishment and regeneration, maintaining its original active components and extending the service life of the etching solution. The oil phase is purified and reused after staged water washing and impurity removal, while the enriched metal is transferred to the subsequent back-extraction and electrolysis units to achieve deep recovery of copper resources. Furthermore, the acid solution after electrolysis is refluxed to form a closed loop, avoiding acid resource loss and waste liquid discharge problems. The overall regeneration and recycling system of this invention is based on the synergistic logic of "phase separation + closed-loop circulation" in the overall reaction process, which enhances the etching solution regeneration capacity while taking into account system stability, safety, and economy. By combining the above-mentioned related features, this utility model effectively solves the technical problems existing in the background technology, such as the difficulty in controlling the enrichment of copper ions in etching solution, high processing costs, and the coexistence of etching performance decline and safety risks, and realizes the efficient recycling of etching solution and green recovery of copper resources.

[0040] In step S1, the extractant includes one or more of P204 extractant, TBP extractant, Lix984 extractant, and N235 extractant.

[0041] Compared with existing technologies, the above-mentioned technical solution can enhance the selective binding ability of copper ions and improve extraction efficiency through the optimized combination of synergistic extractants. P204 has a strong phosphate ester coordination ability, TBP helps to improve the dispersibility and mass transfer performance of the extractant, and Lix984 and N235 show good extraction ability and stability for copper ions and other heavy metals, respectively. This invention preferentially transfers copper ions to the oil phase through the complexation reaction between the multi-component organic phase and the aqueous phase, forming a stable copper-extractant complex. This reduces the interfacial tension between the extraction phases, makes the reaction more complete, and removes copper more thoroughly, thereby significantly improving the extraction and separation efficiency and inhibiting the co-extraction of impurities.

[0042] In step S2, the oil phase treatment is achieved through a primary water washing unit and a secondary water washing unit separated by an overflow baffle, including the following steps: the oil phase is initially washed in the primary water washing unit to remove most of the entrained water phase and solid impurities to obtain a semi-finished product; then, the semi-finished product is overflowed to the secondary water washing unit through the overflow baffle for deep washing to obtain a qualified purified oil phase, and microwave radiation is applied through a microwave radiator; then, the purified oil phase is output from the secondary water washing unit to the extraction device, and the liquid flowing down from the bottom of the secondary water washing unit passes through a hydrocyclone separator, which, together with the microwave radiator, promotes the aggregation of metal particles, while the metal concentrate is collected from the bottom of the primary and secondary units to the back-extraction device.

[0043] Compared with existing technologies, the above-mentioned technical solution, by setting up a two-stage water washing system with an overflow baffle in between, allows the oil phase after the primary water washing to automatically flow into the deep washing unit, thereby forming a dynamic gradient washing environment. The water phase and solid impurities entrained in the oil phase can be removed in stages, the extractant is fully purified, and metal ions are gradually deposited and enriched at the bottom. Finally, the purified oil phase can be recycled, improving the utilization rate of the extractant, obtaining a higher purity metal concentrate, improving the efficiency of back-extraction and electrolysis, and optimizing the closed-loop stability of the entire resource recovery process.

[0044] In step S3, the acid solution includes one of sulfuric acid, nitric acid, and hydrochloric acid, and step S3 also includes the step of feeding the regenerated acid solution obtained after producing cathode copper into the back-extraction device through the regenerated acid outlet from the acid inlet.

[0045] Compared with the existing technology, the above technical solution uses the displacement reaction of hydrogen ions in strong acid to dissociate and transfer copper ions in the copper-extractant complex in the oil phase to the aqueous phase, forming a copper-enriched solution. The copper ions are efficiently transferred out of the organic phase and enter the electrolysis device to be reduced to metallic copper. The remaining acid solution after the reaction is not consumed in large quantities and can be recovered and injected into the back-extraction device. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the regeneration and recycling system of the TFT-LCD copper etching solution of this utility model;

[0047] Figure 2 This is a schematic diagram of the regeneration and circulation system of the TFT-LCD copper etching solution of this utility model;

[0048] Explanation of reference numerals in the attached figures:

[0049] Figure 1In the middle section, 1. Extraction device; 11. Aqueous phase outlet; 12. Oil phase outlet; 13. Active reflux inlet; 14. Purified extractant inlet; 2. Water washing device; 21. First water washing unit; 22. Second water washing unit; 23. Concentrated metal liquid outlet; 24. Purified extractant outlet; 25. Overflow baffle; 26. Microwave radiator; 27. Cyclone separator; 3. Circulation device; 31. Copper ion concentration sensor; 32. Regeneration liquid replenishment device; 321. Solenoid valve; 4. Back-extraction device; 41. Acid inlet; 42. Ultrasonic anti-crystallization device; 5. Electrolysis device; 51. Regenerated acid outlet. Detailed Implementation

[0050] First, those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the embodiments of this application and are not intended to limit the scope of protection of the embodiments of this application. Those skilled in the art can make adjustments as needed to adapt to specific application scenarios.

[0051] To address the technical challenges in TFT-LCD manufacturing, such as the large volume of etching solution used, the risk of explosion due to the self-decomposition of hydrogen peroxide catalyzed by copper ions, poor etching performance, and the complexity of adding etching additives, this invention provides a TFT-LCD copper etching solution regeneration and recycling system to achieve the technical effects of reducing etching solution usage, avoiding explosion risks, restoring etching performance, and reducing manufacturing costs.

[0052] The technical solution adopted by this utility model to solve its technical problem is as follows: Figure 1As shown, a TFT-LCD copper etching solution regeneration and recycling system is provided, including an extraction device 1, a water washing device 2, a circulation device 3, a back-extraction device 4, and an electrolysis device 5. The extraction device 1 is connected to an external wastewater discharge port and is equipped with an aqueous phase outlet 11, an oil phase outlet 12, an active reflux inlet 13, and a purified extractant inlet 14. The inlet of the circulation device 3 is connected to the aqueous phase outlet 11, and the outlet of the circulation device 3 is connected to the active reflux inlet 13. A copper ion concentration sensor 31 is installed within the circulation device 3, and the copper ion concentration sensor 31 is communicatively connected to the control system. The circulation device 3 is also equipped with a regeneration liquid replenishment device 32, which is equipped with an electromagnetic valve 321 and is communicatively connected to the control system. The regeneration liquid replenishment device 32 is used to replenish hydrogen peroxide or untreated etching solution into the circulation device 3. The inlet of the water washing device 2 is connected to the oil phase outlet 12, and the water washing device 2 is equipped with a concentrated metal liquid outlet 23 and a purification extractant outlet 24. The purified regeneration liquid outlet is connected to the purification extractant inlet 14, and the water washing device 2 is equipped with a microwave radiator 24. The inlet of the back-extraction device 4 is connected to the concentrated metal liquid outlet 23, and the outlet of the back-extraction device 4 is connected to the electrolysis device 5.

[0053] Preferably, the electrolysis device 5 is further provided with a regenerated acid outlet 51, and the regenerated acid outlet 51 is connected to the acid inlet 41 provided on the back-extraction device 4.

[0054] Preferably, the concentrated metal liquid outlet 23 is located at the bottom of the water washing device 2, and the purification extractant outlet 24 is located on the side of the water washing device 2.

[0055] Preferably, the washing device 2 includes a primary washing unit 21 and a secondary washing unit 22 separated by a liquid flow transfer component. The inlet of the primary washing unit 21 is connected to the oil phase outlet 12. The bottom of both the primary washing unit 21 and the secondary washing unit 22 is provided with a concentrated metal liquid outlet 23. The purification extractant outlet 24 is located on the side of the secondary washing unit 22. The microwave radiator 26 is located at the bottom of the secondary washing unit 22.

[0056] Preferably, the liquid flow transfer component is an overflow baffle, which is disposed between the first washing unit 21 and the second washing unit 22, and the top of the baffle is 200-300mm lower than the top surface of the first washing unit 21, thereby forming an overflow channel. The concentrated metal liquid outlet 23 at the bottom of the second washing unit 22 is connected to the back-extraction device 4 through a hydrocyclone separator 27.

[0057] Preferably, an anti-siphon U-shaped pipe is provided between the concentrated metal liquid outlets 23, and the height of the anti-siphon U-shaped pipe is ≥300 mm.

[0058] Preferably, a backflow prevention check valve is provided between the purification extractant outlet 24 and the purification extractant inlet 14.

[0059] Preferably, the bottom of the back-extraction device 4 is a conical structure with a cone angle of 60-90°. The lowest point of the conical structure is the outlet of the back-extraction device 4, and the bottom of the back-extraction device 4 is provided with an ultrasonic anti-crystallization device 42.

[0060] Existing technologies, such as the utility model patent with authorization announcement number CN205529043U mentioned in the background section, only use simple pipe connections and completely lack a copper ion concentration monitoring mechanism. This utility model, however, integrates a copper ion concentration sensor 31 and a control system (not shown in the figure) at the bottom of the circulation device 3. By real-time detection of the copper ion concentration in the aqueous phase, it automatically triggers the addition of hydrogen peroxide or etching solution when the copper ion concentration > 500 ppm, fundamentally solving the explosion hazard of copper ion catalytic hydrogen peroxide self-decomposition. This safe closed-loop design improves the system's risk response speed and completely overcomes the major safety defects not addressed in the background technology. Furthermore, existing technologies rely on static RO membrane filtration, which has a rejection rate of less than 30% for colloidal copper particles with a particle size <1 μm. The low percentage of copper residue in the oil phase leads to a relatively low number of extraction solvent cycles, typically less than 50. This invention introduces a microwave radiator 26 in conjunction with a cyclone separator 27 in the washing device 2. Microwaves (typically 2.45 GHz) promote the agglomeration of colloidal copper particles. The cyclone separator 27 can achieve a 99% retention rate for particles >5μm. Furthermore, the synergy between the two and the microwave radiator further reduces the residual copper content in the oil phase, increasing the extraction solvent cycle life to over 200 cycles, resulting in a significant leap in resource utilization. Additionally, this invention integrates a variable frequency ultrasonic module 42 at the bottom of the back-extraction device 4, further suppressing crystal nucleus formation at the bottom of the back-extraction device, thus increasing the overall operating cycle of the equipment and solving the long-standing problem of "crystallization paralysis" in the field of etching solution regeneration.

[0061] In summary, the technological breakthrough of this utility model stems from the integration of three technologies: sensing and control, physical field enhancement, and structural innovation. Its closed-loop safety protection system, microwave-assisted phase separation mechanism, and intelligent anti-crystallization system achieve synergistic optimization of "safety, efficiency, and stability" for the first time in the field of etching solution regeneration, providing an unprecedented industrial solution for the TFT-LCD manufacturing industry.

[0062] The principle of this invention's system for diverting and regenerating waste liquid is as follows: Figure 2 As shown, the reaction process specifically includes the following steps:

[0063] S1: Extraction treatment: Copper-containing etching waste liquid is fed into extraction device 1 through waste liquid discharge port. Under the action of extractant, it is mixed and mass transferred to separate the aqueous phase and oil phase.

[0064] S2: Dual-path regeneration process: Aqueous phase treatment: The aqueous phase is sent to the circulation device 3 through the aqueous phase outlet 11 of the extraction device 1, and hydrogen peroxide or untreated etching solution is added to obtain regenerated etching solution; Oil phase treatment: The oil phase is sent to the water washing device 2 through the oil phase outlet 12 of the extraction device 1 for water washing treatment to obtain purified oil phase and metal concentrate. The purified oil phase is sent to the extraction device 1 through the purified extractant outlet 24 to the purified extractant inlet 14 for processing. The metal concentrate is sent to the back-extraction device 4 through the concentrated metal liquid outlet 23.

[0065] S3: Electrolytic copper removal from metal: In the back-extraction device 4, the metal concentrate is mixed with acid solution for back-extraction treatment to obtain a copper-rich solution. Then, the copper-rich solution is passed into the electrolysis device 5 for electrolysis to produce cathode copper, thus completing the process.

[0066] Preferably, in step S1, the extractant includes one or more of P204 extractant, TBP extractant, Lix984 extractant, and N235 extractant.

[0067] Preferably, in step S2, the oil phase treatment is achieved through a primary water washing unit 21 and a secondary water washing unit 22 separated by an overflow baffle, including the following steps: the oil phase is initially washed in the primary water washing unit 21 to remove most of the entrained water phase and solid impurities to obtain a semi-finished product; then the semi-finished product is overflowed to the secondary water washing unit 22 through the overflow baffle, and a deep wash is performed in the secondary water washing unit 22 to obtain a qualified purified oil phase, and microwave radiation is applied through the microwave radiator 26; then the purified oil phase is output from the secondary water washing unit 22 to the extraction device 1, and the liquid flowing down from the bottom of the secondary water washing unit 22 passes through the hydrocyclone separator 321, which, together with the microwave radiator 26, promotes the aggregation of metal particles, while the metal concentrate is collected from the bottom of the primary and secondary units to the back-extraction device.

[0068] Preferably, in step S3, the acid solution includes one of sulfuric acid, nitric acid, and hydrochloric acid, and step S3 further includes the step of feeding the regenerated acid solution obtained after producing cathode copper into the back-extraction device 4 through the regenerated acid outlet 51 from the acid inlet 41.

[0069] The beneficial effects of this invention are as follows: by extracting and removing copper ions from the etching solution, the etching performance is restored, avoiding the explosion risk caused by the self-decomposition of hydrogen peroxide catalyzed by copper ions. This system can significantly increase the service life of the etching solution and reduce the amount of etching solution used in TFT-LCD manufacturing, thereby greatly reducing manufacturing costs. Experimental results show that the etching solution treated by this system is comparable to the original solution in key performance indicators such as EPD, Cd bias, and Taper angle, proving the effectiveness of this invention. Furthermore, this system achieves resource recycling through electrolytic recovery of copper resources, resulting in significant economic and environmental benefits.

[0070] The technical solution of this utility model will be further elaborated below by providing different embodiments and combining different diversion and regeneration conditions:

[0071] Example 1:

[0072] This embodiment provides a TFT-LCD copper etching solution regeneration and recycling system, including an extraction device 1, a water washing device 2, a circulation device 3, a back-extraction device 4, and an electrolysis device 5.

[0073] The extraction device 1 is connected to an external waste liquid discharge port to receive copper-containing etching waste liquid. The extraction device 1 is equipped with an aqueous phase outlet 11, an oil phase outlet 12, an active reflux inlet 13, and a purified extractant inlet 14. The aqueous phase outlet 11 is located at the bottom of the extraction device 1 and is used to discharge the extracted aqueous phase liquid; the oil phase outlet 12 is located at the top of the extraction device 1 and is used to discharge the extracted oil phase liquid; the active reflux inlet 13 is located on the side of the extraction device 1 and is used to receive the regenerated etching liquid from the circulation device 3; the purified extractant inlet 14 is located at the top of the extraction device 1 and is used to receive the purified extractant from the water washing device 2.

[0074] The inlet of the circulation device 3 is connected to the aqueous phase outlet 11 of the extraction device 1 to receive the aqueous phase liquid after extraction. The outlet of the circulation device 3 is connected to the active reflux inlet 13 of the extraction device 1 to return the regenerated etching solution to the extraction device 1. The circulation device 3 is equipped with a stirring device to fully mix the aqueous phase with the added hydrogen peroxide or untreated etching solution to form the regenerated etching solution.

[0075] The circulation device 3 is equipped with a copper ion concentration sensor 31, which is communicatively connected to the control system. The circulation device 3 is also equipped with a regeneration solution replenishment device 32, which is equipped with an electromagnetic valve 321, which is communicatively connected to the control system. The regeneration solution replenishment device 32 is used to replenish hydrogen peroxide or untreated etching solution into the circulation device 3.

[0076] The inlet of the washing device 2 is connected to the oil phase outlet 12 of the extraction device 1 to receive the oil phase liquid after extraction. The washing device 2 is equipped with a concentrated metal liquid outlet 23 and a purified extractant outlet 24. A microwave radiator 24 is installed inside the washing device 2, located at its bottom. The microwave radiator has a frequency of 2.45 GHz and a power of 0.5-5 kW. The concentrated metal liquid outlet 23 is located at the bottom of the washing device 2 to discharge the metal concentrate that settles after washing. The purified extractant outlet 24 is located on the side of the washing device 2 to discharge the purified oil phase after washing. The purified extractant outlet 24 is connected to the purified extractant inlet 14 of the extraction device 1, forming a recycling path for the extractant.

[0077] The inlet of the back-extraction unit 4 is connected to the concentrated metal liquid outlet 23 of the water washing unit 2, for receiving the metal concentrate after water washing. The outlet of the back-extraction unit 4 is connected to the electrolysis unit 5, for conveying the copper-containing enriched solution obtained after back-extraction to the electrolysis unit 5 for electrolysis. The back-extraction unit 4 is also equipped with an acid inlet 41 for receiving the regenerated acid solution generated by the electrolysis unit 5.

[0078] The electrolysis unit 5 is equipped with a regenerated acid outlet 51, which is connected to the acid inlet 41 on the back-extraction unit 4. This outlet is used to return the regenerated acid solution generated after electrolysis to the back-extraction unit 4, thereby achieving acid recycling. The electrolysis unit 5 includes an electrolytic cell, a cathode plate, and an anode plate. The electrolytic cell is used to contain a copper-enriched solution, the cathode plate is used to deposit copper, and the anode plate is used for the oxidation reaction.

[0079] An anti-siphon U-tube is installed between the concentrated metal liquid outlet 23 and the outlet 23, and the height of the anti-siphon U-tube is ≥300 mm. The anti-siphon U-tube can effectively prevent the liquid from forming a siphon phenomenon in the pipeline, ensuring the stability and controllability of the liquid flow in all parts of the system.

[0080] A backflow prevention check valve is provided between the purification extractant outlet 24 and the purification extractant inlet 14. The backflow prevention check valve can ensure that the purification extractant can only flow from the water washing device 2 to the extraction device 1, preventing the liquid in the extraction device 1 from flowing back to the water washing device 2, and ensuring the normal operation of the system.

[0081] The bottom of the back-extraction device 4 has a conical structure with a cone angle of 90°, and the lowest point of the cone is the outlet of the back-extraction device 4. This design allows the copper-enriched solution after back-extraction to naturally collect at the outlet for easy discharge. The bottom of the back-extraction device 4 is equipped with an ultrasonic anti-crystallization device 42, which uses ultrasonic vibration to prevent copper ions from crystallizing and depositing during the back-extraction process, ensuring that the copper-enriched solution can flow smoothly into the electrolysis device 5.

[0082] The washing device 2 includes a primary washing unit 21 and a secondary washing unit 22 separated by a liquid flow transfer component. The inlet of the primary washing unit 21 is connected to the oil phase outlet 12 of the extraction device 1 to receive the oil phase liquid after extraction. Both the primary washing unit 21 and the secondary washing unit 22 have a concentrated metal liquid outlet 23 at their bottom to discharge the metal concentrate that settles during the washing process. The microwave radiator 24 is located at the bottom of the secondary washing unit 22. The purified extractant outlet 24 is located on the side of the secondary washing unit 22 to discharge the purified oil phase after the two-stage washing process. The concentrated metal liquid outlet 23 at the bottom of the secondary washing unit 22 is connected to the back-extraction device 4 via a hydrocyclone separator 27.

[0083] The liquid flow transfer component is an overflow baffle, which is set between the first washing unit 21 and the second washing unit 22. The top of the baffle is 250mm lower than the top surface of the first washing unit 21, thus forming an overflow channel. This design allows the liquid in the first washing unit 21 to flow naturally into the second washing unit 22 through the overflow channel after reaching a certain height, achieving continuous two-stage washing treatment.

[0084] The system of this embodiment is used to divert and regenerate waste liquid. This diversion and regeneration method relies on the above-mentioned TFT-LCD copper etching solution regeneration and circulation system, and includes the following steps:

[0085] S1: Extraction process:

[0086] The copper-containing etching waste liquid is fed into the extraction device 1 through the waste liquid discharge port. Under the action of the extractant, the aqueous phase and oil phase are separated through mixing and mass transfer.

[0087] The composition of the copper-molybdenum etching solution waste liquid includes: 20% hydrogen peroxide, 3% iminodiacetic acid, 0.1% 5-amino-4-azazole, 0.5% sodium fluoride, and 1% sulfuric acid. It is used to etch copper / molybdenum film layers until the copper ion concentration reaches 2000 ppm.

[0088] The extractant is a mixture of P204 / TBP / sulfonated kerosene (volume ratio: 2:1:7). During the extraction process, the extractant comes into full contact with and mixes with the copper-containing etching waste liquid. The extractant selectively binds to copper ions in the waste liquid to form a copper-extractant complex. This complex is mainly distributed in the oil phase, while other components remain mainly in the aqueous phase, thereby achieving the separation of copper ions.

[0089] S2: Dual-path regeneration processing:

[0090] Aqueous phase treatment: The aqueous phase is transported to the circulation device 3 via the aqueous phase outlet 11 of the extraction device 1, and hydrogen peroxide or untreated etching solution is added to obtain regenerated etching solution. In the circulation device 3, the aqueous phase is thoroughly mixed with the added hydrogen peroxide or untreated etching solution to restore the etching ability of the aqueous phase and form regenerated etching solution. The regenerated etching solution is transported to the active reflux inlet 13 of the extraction device 1 through the outlet of the circulation device 3 for reuse; during this period, the copper ion concentration in the circulation device 3 is monitored in real time by a copper ion concentration sensor 31, which is communicatively connected to the control system. The regenerated solution replenishment device 32 in the circulation device 3 is equipped with a solenoid valve 321, which automatically triggers the addition of hydrogen peroxide or etching solution if the copper ion concentration is >500ppm.

[0091] Oil phase treatment: The oil phase is conveyed through the oil phase outlet 12 of the extraction device 1 to the water washing device 2 for water washing treatment to obtain purified oil phase and metal concentrate. The oil phase treatment is achieved through a first water washing unit 21 and a second water washing unit 22 separated by an overflow baffle. The oil phase undergoes primary cleaning in the first water washing unit 21 to remove most of the entrained water phase and solid impurities, resulting in a semi-finished product. The semi-finished product then overflows through an overflow baffle to the second water washing unit 22 for deep cleaning. Microwave radiation is applied by a microwave radiator 26 to obtain a purified oil phase. The liquid flowing down from the bottom of the second water washing unit 22 passes through a hydrocyclone separator 321, which, together with the microwave radiator 26, promotes the aggregation of metal particles. The purified oil phase is output from the second water washing unit 22 to the extraction device 1. Simultaneously, metal concentrates are collected from the bottom of the first and second water washing units and sent to the back-extraction device 4. Afterward, the purified oil phase is output from the second water washing unit 22 to the extraction device 1. In the first water washing unit 21, the oil phase and water are fully mixed and in contact. During the washing process, the water phase washes away impurities and some water-soluble substances entrained in the oil phase, resulting in preliminary purification of the oil phase. The oil phase semi-finished product after primary cleaning overflows through the overflow baffle to the second water washing unit 22, where it undergoes deep cleaning to further remove residual impurities and obtain a qualified purified oil phase. The purified oil phase is then transported through the purified extractant outlet 24 to the purified extractant inlet 14 of the extraction device 1 for reuse. The metal concentrate that settles during the water washing process is collected from the concentrated metal liquid outlet 23 at the bottom of the first water washing unit 21 and the second water washing unit 22 and transported to the back-extraction device 4.

[0092] S3: Electrolytic copper removal from metals:

[0093] In the back-extraction unit 4, the metal concentrate is mixed with acid solution for back-extraction to obtain a copper-rich solution. This copper-rich solution is then passed into the electrolysis unit 5 for electrolysis, producing cathode copper and completing the process. The acid solution includes one of sulfuric acid, nitric acid, or hydrochloric acid. During the back-extraction process, the acid solution and metal concentrate are thoroughly mixed. Hydrogen ions in the acid solution displace copper ions from the copper-extractant complex, allowing the copper ions to enter the aqueous phase, forming the copper-rich solution, while the extractant returns to the oil phase. The copper-rich solution is then transported to the electrolysis unit 5 through the outlet of the back-extraction unit 4 for electrolysis. During electrolysis, copper ions are reduced and deposited on the cathode plate to form cathode copper, while oxidation occurs on the anode plate. The regenerated acid solution produced after electrolysis is fed back into the back-extraction unit 4 through the regenerated acid outlet 51 from the acid inlet 41, achieving acid recycling.

[0094] In Example 1, after extraction, the copper ion concentration in the copper-molybdenum etching solution decreased to 300 ppm. The etching evaluation results are shown in Table 1.

[0095] Example 2:

[0096] Example 2 is similar to Example 1, using the same regeneration cycle system. The difference lies in the conditions of the diversion regeneration method. The composition of the copper-molybdenum etching solution waste liquid is: 20% hydrogen peroxide / 3% iminodiacetic acid / 0.1% 5-amino-4-azazole / 0.5% sodium fluoride / 1% sulfuric acid. The copper / molybdenum film layer is etched until the copper ion concentration reaches 5000 ppm.

[0097] The copper-molybdenum etching solution was extracted using P204 / TBP / sulfonated kerosene (volume ratio: 2:1:7). After extraction, the copper ion concentration in the copper-molybdenum etching solution was reduced to 500 ppm. The treated etching solution was then mixed with a fresh copper-molybdenum etching solution at a volume ratio of 1:1. The mixture was then used for etching evaluation, and the results are shown in Table 1.

[0098] Example 3:

[0099] Example 3 is similar to Example 1, using the same regeneration cycle system. The difference lies in the conditions of the diversion regeneration method. The composition of the copper-molybdenum etching solution waste liquid is: 20% hydrogen peroxide / 3% iminodiacetic acid / 0.1% 5-amino-4-azazole / 0.5% sodium fluoride / 1% sulfuric acid. The copper / molybdenum film layer is etched until the copper ion concentration reaches 5000 ppm.

[0100] The copper-molybdenum etching solution was extracted using a P204 / TBP / sulfonated kerosene (volume ratio: 2:1:7). After extraction, the copper ion concentration in the etching solution decreased to 500 ppm. Hydrogen peroxide was added to bring the mass content to 20%, and the etching solution after addition was then evaluated. The results are shown in Table 1.

[0101] Example 4:

[0102] Example 4 is similar to Example 1, using the same regeneration cycle system. The difference lies in the conditions of the diversion regeneration method. The composition of the copper-molybdenum etching solution waste liquid is: 20% hydrogen peroxide / 3% iminodiacetic acid / 0.1% 5-amino-4-azazole / 0.5% sodium fluoride / 1% sulfuric acid. The copper / molybdenum film layer is etched until the copper ion concentration reaches 2000 ppm.

[0103] The copper-molybdenum etching solution was extracted using P204 / TBP / sulfonated kerosene (volume ratio: 2:1:7). After extraction, the copper ion concentration in the etching solution decreased to 300 ppm. The etching solution was then further extracted with N235 extractant to remove molybdenum ions, and the etching evaluation results are shown in Table 1.

[0104] Table 1: Evaluation of waste liquid after diversion and regeneration in Examples 1-4:

[0105]

[0106] As shown in Table 1, the etchants treated by the TFT-LCD copper etching solution regeneration and recycling system of this invention in Examples 1-4 exhibit performance close to that of the original solution in terms of key parameters such as EPD value, Cd bias, and Taper angle, with differences controlled within an acceptable range. This indicates that the regeneration process provided by this invention can effectively recover copper and other metals while maintaining the functional stability of the etching solution. Specifically, Examples 1-3, by adjusting the regeneration path (including adding hydrogen peroxide or the ratio of new solution) at different initial copper concentrations, still achieved low copper residue and maintained good etching characteristics. Example 4, further combined with a molybdenum extraction step, verified the compatible recovery capability of this regeneration and recycling system for multiple metal components. In summary, this invention possesses significant advantages such as high etching solution reuse efficiency, high metal recovery rate, and strong process compatibility, demonstrating promising prospects for industrial application.

[0107] In summary, the TFT-LCD copper etching solution regeneration and recycling system of this invention achieves efficient treatment and resource recycling of copper etching waste liquid through three steps: extraction, dual-path regeneration treatment, and metal electrolytic copper removal. Specifically, the extraction treatment separates the copper-containing etching waste liquid into an aqueous phase and an oil phase. The dual-path regeneration treatment processes the aqueous phase and the oil phase separately. The aqueous phase treatment yields regenerated etching solution, and the oil phase treatment yields purified oil phase and metal concentrate. Metal electrolytic copper removal recovers copper from the metal concentrate as cathode copper. The entire process realizes the recycling of etching solution and the recovery of copper resources, resulting in significant economic and environmental benefits.

[0108] In the description of the embodiments of this application, it should be noted that the terms "inner" and "outer" and other terms indicating direction or positional relationship are based on the direction or positional relationship shown in the drawings. This is only for the convenience of description and does not indicate or imply that the device or component must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this application.

[0109] In the description of this application, the references to terms such as "an embodiment," "some embodiments," "in this embodiment," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0110] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A TFT-LCD copper etching solution regeneration and recycling system, characterized in that, include: The apparatus comprises an extraction unit (1), a water washing unit (2), a circulation unit (3), a back-extraction unit (4), and an electrolysis unit (5), wherein: The extraction device (1) is connected to an external waste liquid discharge port. The extraction device (1) is provided with an aqueous phase outlet (11), an oil phase outlet (12), an active reflux inlet (13), and a purification extractant inlet (14). The inlet of the circulation device (3) is connected to the aqueous phase outlet (11), and the outlet of the circulation device (3) is connected to the active reflux inlet (13). The circulation device (3) is equipped with a copper ion concentration sensor (31), which is connected to the control system. The circulation device (3) is also equipped with a regenerated liquid replenishment device (32), which is equipped with an electromagnetic valve (321), which is connected to the control system. The regenerated liquid replenishment device (32) is used to replenish hydrogen peroxide or untreated etching solution into the circulation device (3). The inlet of the water washing device (2) is connected to the oil phase outlet (12), and the water washing device (2) is provided with a concentrated metal liquid outlet (23) and a purification extractant outlet (24). The purification regeneration liquid outlet is connected to the purification extractant inlet (14), and a microwave radiator (26) is provided inside the water washing device (2). The inlet of the back-extraction device (4) is connected to the outlet (23) of the concentrated metal liquid, and the outlet of the back-extraction device (4) is connected to the electrolysis device (5).

2. The TFT-LCD copper etching solution regeneration and recycling system according to claim 1, characterized in that, The electrolysis device (5) is also provided with a regenerated acid outlet (51), and the regenerated acid outlet (51) is connected to the acid inlet (41) provided on the back-extraction device (4).

3. The TFT-LCD copper etching solution regeneration and recycling system according to claim 1, characterized in that, The concentrated metal liquid outlet (23) is located at the bottom of the water washing device (2), and the purification extractant outlet (24) is located on the side of the water washing device (2).

4. The TFT-LCD copper etching solution regeneration and recycling system according to claim 1, characterized in that, The washing device (2) includes a first washing unit (21) and a second washing unit (22) separated by a liquid flow transfer component. The inlet of the first washing unit (21) is connected to the oil phase outlet (12). The bottom of the first washing unit (21) and the second washing unit (22) are provided with concentrated metal liquid outlets (23). The purification extractant outlet (24) is located on the side of the second washing unit (22). The microwave radiator (26) is located at the bottom of the second washing unit (22).

5. The TFT-LCD copper etching solution regeneration and recycling system according to claim 4, characterized in that, The liquid flow transfer component is an overflow baffle (25), which is disposed between the first washing unit (21) and the second washing unit (22), and the top of the overflow baffle (25) is 200-300mm lower than the top surface of the first washing unit (21), thereby forming an overflow channel.

6. The TFT-LCD copper etching solution regeneration and recycling system according to claim 4, characterized in that, The concentrated metal liquid outlet (23) at the bottom of the second water washing unit (22) is connected to the back-extraction device (4) through a hydrocyclone separator (27).

7. The TFT-LCD copper etching solution regeneration and recycling system according to claim 1, characterized in that, The concentrated metal liquid outlet (23) is equipped with an anti-siphon U-shaped pipe, and the height of the anti-siphon U-shaped pipe is ≥300 mm.

8. The TFT-LCD copper etching solution regeneration and recycling system according to claim 1, characterized in that, A backflow prevention check valve is provided between the purification extractant outlet (24) and the purification extractant inlet (14).

9. The TFT-LCD copper etching solution regeneration and recycling system according to claim 1, characterized in that, The bottom of the back-extraction device (4) is a conical structure with a cone angle of 60-90°, and the bottom of the back-extraction device (4) is provided with an ultrasonic anti-crystallization device (42).

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