A printed circuit board electroplating cleaning solution circulation treatment device and method

Abstract

The present application relates to the technical fields of electroplating cleaning liquid circulation treatment reactor, and particularly relates to a printed circuit board electroplating cleaning liquid circulation treatment device and method, which comprises a controller, a cleaning tank, a liquid collecting tank communicated with the cleaning tank, a liquid inlet pipe arranged between the liquid collecting tank and the cleaning tank, a circulating pump arranged at the liquid outlet end of the liquid collecting tank, a pre-filter, a polishing resin column and a liquid return pipe, and further comprises a coaxial shunt limited domain regeneration cylinder; the liquid inlet end of the coaxial shunt limited domain regeneration cylinder is provided with a rotary shunt valve core and a pollution load detection assembly. Compared with the prior art, the present application sets a central straight-through pipe and an annular limited domain regeneration cavity in the coaxial shunt limited domain regeneration cylinder, and adjusts the flow ratio between the central straight-through pipe and the annular limited domain regeneration cavity according to the overall pollution load of the cleaning liquid by using the pollution load detection assembly and the rotary shunt valve core; the proportion of the cleaning liquid entering the annular limited domain regeneration cavity is increased and the cleaning liquid is subjected to intensive treatment.

Description

Technical Field

[0001] This invention relates to the field of electroplating cleaning solution circulation treatment technology, and in particular to a device and method for circulating electroplating cleaning solution for printed circuit boards. Background Technology

[0002] After copper, nickel, tin, and other surface treatment processes, printed circuit boards typically require one or more washing steps to remove residual plating solution, metal salts, complexing agents, brighteners, leveling agents, and other organic additives from the board surface. This type of cleaning solution differs from ordinary heavy metal-containing wastewater; its contamination load exhibits significant instantaneous fluctuations. When the amount of liquid carried out by the circuit board is small, the content of metal ions and organic complexes in the cleaning solution is low. However, when the production cycle accelerates, the amount of liquid carried over the board increases, or plating solution is replenished, the concentration of complexed copper, nickel, or tin metal contaminants in the cleaning solution rises rapidly within a short period.

[0003] Current circulating treatment of electroplating cleaning solutions for printed circuit boards often employs a series of processing units, including filtration, oxidation, ion exchange, reverse osmosis, electrodialysis, electrolysis, or resin polishing. This approach typically sends all cleaning solutions into the same treatment process, subjecting low-contamination-load and high-complexation-load solutions to the same treatment intensity. When the cleaning solution has a low contamination load, performing complexation breaking, electromigration, or resin adsorption on all solutions results in wasted reagents, electricity, and resin capacity. Furthermore, when the cleaning solution experiences an increase in complexed metal contaminants due to the impact of the carryover liquid, ordinary resin adsorption or membrane separation is insufficient to capture these complexed metals in a timely manner, easily leading to resin permeation, membrane fouling, or fluctuations in the quality of recycled water.

[0004] In the prior art, Chinese patent document CN115340230B discloses a resource-based treatment device for recovering heavy metals from complexed heavy metal wastewater. This solution includes a wastewater separation and concentration component, an oxidation and complex-breaking component, an electrolytic recovery component, and an intelligent detection component. It separates and concentrates the complexed heavy metal wastewater, then breaks down the complexes and electrolyzes the concentrated water for recovery. This solution can solve the problem of resource-based recovery of complexed heavy metal wastewater, but its processing logic still involves first separating and concentrating the wastewater, then sending the concentrated solution to the subsequent complex-breaking and electrolysis units. It is suitable for relatively centralized wastewater treatment scenarios.

[0005] For the online recycling of electroplating cleaning tanks for printed circuit boards (PCBs), the cleaning solution needs to be returned to the tank for continued use within a short time. If all the cleaning solution enters the concentration, complex breaking, and electrochemical treatment processes, not only will the process resistance be high and the treatment intensity be high, but the pH value and redox state of the returned cleaning solution will also be easily altered. If only end-resin or membrane unit polishing is relied upon, it will be unable to cope with the instantaneous impact of complexed metal contaminants in a timely manner. Therefore, the core problem that the existing technology really needs to solve is: how to increase the short-pass ratio to avoid over-treatment when the overall contamination load of the cleaning solution is low, without interrupting the recycling of PCB electroplating cleaning solution, while increasing the proportion of cleaning solution entering the confined complex breaking and metal trapping area when the overall contamination load increases, and completing the remixing and stabilization before returning to the cleaning tank. Therefore, this application discloses a PCB electroplating cleaning solution recycling treatment device and method. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a circulating treatment device and method for electroplating cleaning solution of printed circuit boards, so as to solve the problem that in the existing electroplating cleaning solution circulating treatment process, when the overall pollution load is low, the circulating cleaning solution is over-treated, while when the overall pollution load increases, it is difficult to break down and capture complexed metal pollutants in time, resulting in increased chemical consumption, power consumption and resin load, and fluctuations in the water quality of the return cleaning solution.

[0007] To achieve the above objectives, the present invention provides a circulating treatment device for electroplating cleaning solution of printed circuit boards, comprising a controller, a cleaning tank, a collection tank communicating with the cleaning tank, an inlet pipe disposed between the collection tank and the cleaning tank, a circulating pump disposed at the outlet end of the collection tank, a pre-filter, a polishing resin column, and a return pipe, and further comprising a coaxial diversion and confined regeneration cylinder, wherein the coaxial diversion and confined regeneration cylinder is disposed between the pre-filter and the polishing resin column, and the coaxial diversion and confined regeneration cylinder comprises an outer cylinder, a central straight pipe disposed along the axial direction of the outer cylinder, and an annular confined regeneration cavity formed between the inner wall of the outer cylinder and the outer wall of the central straight pipe; The inlet end of the coaxial diversion and confinement regeneration cylinder is equipped with a rotary diversion valve core and a contamination load detection component. The rotary diversion valve core has a straight diversion port connected to the central straight pipe and a regeneration diversion port connected to the annular confinement regeneration chamber. The electroplating cleaning solution in the cleaning tank is introduced into the collection tank through the inlet pipe, and then sent to the pre-filter by the circulation pump. The pre-filtered cleaning solution is then sent to the inlet end of the coaxial diversion and confinement regeneration cylinder. The annular confined regeneration chamber is provided with a spiral confined flow guide plate, a slow-release complex-breaking ring and a diaphragm electromigration trapping assembly in sequence along the liquid flow direction. The coaxial diversion and confined regeneration cylinder has a remixing and stabilizing chamber at its outlet end. The central straight pipe and the annular confined regeneration chamber are both connected to the remixing and stabilizing chamber. The remixing and stabilizing chamber is connected to the return pipe via a polishing resin column. The other end of the return pipe is connected to the cleaning tank. The contamination load detection component is electrically connected to the controller, and the controller is electrically connected to the rotary diversion valve core. The controller adjusts the relative opening of the straight diversion port and the regeneration diversion port according to the overall contamination load of the cleaning fluid detected by the contamination load detection component. When the overall contamination load is lower than the first preset threshold, a large proportion of the cleaning fluid passes through the central straight pipe in a short distance. When the overall contamination load reaches or exceeds the second preset threshold, the proportion of cleaning fluid entering the annular confined regeneration chamber is increased. After the cleaning fluid entering the annular confined regeneration chamber is confined and broken down and electromigrated, it is remixed with the outlet of the central straight pipe, and then flows back to the cleaning tank sequentially through the polishing resin column and the return pipe.

[0008] Preferably, the rotary diverter valve core is rotatably mounted on the liquid inlet end of the outer cylinder, and the straight diverter port and the regeneration diverter port are offset along the circumference of the rotary diverter valve core. When the rotary diverter valve core rotates in the first direction, the opening of the straight diverter port increases and the opening of the regeneration diverter port decreases; when the rotary diverter valve core rotates in the second direction, the opening of the regeneration diverter port increases and the opening of the straight diverter port decreases.

[0009] Preferably, the inner edge of the spiral confining guide plate is fixedly connected to the outer wall of the central straight pipe, and a flow guiding gap is formed between the outer edge of the spiral confining guide plate and the inner wall of the outer cylinder. The flow guiding gap is 2mm to 8mm, and the pitch of the spiral confining guide plate is 1.2 to 3 times the radial width of the annular confining regeneration cavity.

[0010] Preferably, the slow-release complex-breaking ring is an annular microporous tube with multiple drug outlet holes evenly distributed circumferentially. The drug outlet holes are arranged facing the liquid-facing surface of the spiral confining guide plate. The slow-release complex-breaking ring is used to release a non-precipitated complex-breaking regulator, which converts complexed copper, nickel, or tin metal contaminants into electromigrable free or weakly complexed metal ions.

[0011] Preferably, the diaphragm electromigration trapping assembly includes a DC power supply or a pulsed DC power supply, an anode isolation sleeve, an anode component disposed within the anode isolation sleeve and electrically connected to the positive electrode of the DC power supply or the pulsed DC power supply, a cation exchange membrane sleeve, a cathode enrichment cylinder electrically connected to the negative electrode of the DC power supply or the pulsed DC power supply, and a metal enrichment cavity. The cation exchange membrane sleeve is disposed between the annular confined regeneration cavity and the cathode enrichment cylinder, and the gap between the cation exchange membrane sleeve and the cathode enrichment cylinder forms the metal enrichment cavity. The metal enrichment cavity is ion-selectively connected to the annular confined regeneration cavity through the cation exchange membrane sleeve.

[0012] Preferably, an independent anolyte is introduced into the anode isolation sleeve, and the anode component is isolated from the cleaning solution in the annular confined regeneration chamber; the metal enrichment chamber is connected to a concentrated liquid circulation discharge pipe, one end of which is connected to the metal enrichment chamber and the other end is connected to an external metal recovery unit or centralized processing unit; the concentrated liquid circulation discharge pipe is equipped with an intermittent discharge valve, or a small flow circulation pump, an intermittent discharge valve and a sampling port, for circulating and concentrating the metal enrichment solution in the metal enrichment chamber and discharging it intermittently.

[0013] Preferably, the remixing and stabilizing chamber is formed at the liquid outlet end of the coaxial diversion and confined regeneration cylinder. An ORP buffer packing layer is provided inside the remixing and stabilizing chamber near the liquid outlet side. The liquid outlets from the central straight pipe and the annular confined regeneration chamber are first mixed in the remixing and stabilizing chamber, and then enter the polishing resin column through the ORP buffer packing layer.

[0014] Preferably, a pulse backsweep branch is provided between the rear section of the back mixing and stabilizing chamber and the annular confined regeneration chamber. The pulse backsweep branch is electrically connected to the controller. The pulse backsweep branch is used to pulsely guide the cleaning fluid that has passed through the central straight pipe in the back mixing and stabilizing chamber without undergoing complex-breaking and chemical dosing back to the rear section of the annular confined regeneration chamber under low pollution load conditions.

[0015] This invention also discloses a method for circulating a printed circuit board electroplating cleaning solution, applied to the aforementioned printed circuit board electroplating cleaning solution circulating treatment device, comprising the following steps: S1. The electroplating cleaning solution in the cleaning tank is introduced into the collection tank through the inlet pipe, and then sent to the pre-filter by the circulation pump. The pre-filter intercepts suspended particles in the cleaning solution. S2. The pre-filtered cleaning solution is sent to the inlet end of the coaxial diversion and confinement regeneration cylinder, and the contamination load of the cleaning solution is detected by the contamination load detection component. S3. When the pollution load detection component detects that the overall pollution load of the cleaning fluid is lower than the first preset threshold, the controller drives the rotating diversion valve core to make the opening of the straight diversion port greater than the opening of the regeneration diversion port, so that a large proportion of the cleaning fluid enters the central straight pipe and passes through in a short distance. S4. When the pollution load detection component detects that the overall pollution load of the cleaning fluid reaches or exceeds the second preset threshold, the controller drives the rotating diversion valve core to increase the opening of the regeneration diversion port and increase the proportion of cleaning fluid entering the annular confined regeneration chamber. The cleaning fluid entering the annular confined regeneration chamber forms a spiral confined flow under the guidance of the spiral confined guide plate. S5. The slow-release complex-breaking ring-shaped cleaning fluid entering the annular confined regeneration chamber releases a non-precipitated complex-breaking regulator, which converts complexed metal pollutants into electromigable free or weakly complexed metal ions. S6. The cleaning solution after breaking the complex enters the diaphragm electromigration trapping unit. Metal ions migrate through the cation exchange membrane sleeve to the metal enrichment cavity and are enriched or captured by the cathode enrichment cylinder or electrodeposition. S7. The cleaning fluid that passes through the central straight pipe in a short distance is mixed with the cleaning fluid that has been treated in the annular confined regeneration chamber in the return mixing and stabilization chamber. After being treated by the ORP buffer packing layer and the polishing resin column, the mixed cleaning fluid is returned to the cleaning tank through the return pipe.

[0016] Preferably, after S7, when the contamination load detection component detects that the cleaning fluid contamination load is lower than the fallback threshold and continues for a preset time, the controller executes a low-load self-cleaning back scan step: suspending the addition of the slow-release complex-breaking ring, keeping the direct diversion port at a large opening, and making the regeneration diversion port open and close slightly at a cycle of 0.5s to 5s, wherein the fallback threshold is less than or equal to the first preset threshold. At the same time, the operating current of the diaphragm electromigration trapping component is reduced, and the pulse back-sweep branch is activated, so that the cleaning solution that has passed through the central straight pipe in the back-mixing and stabilizing chamber without undergoing complex-breaking dosing is reverse-pulsed across the side of the cation exchange membrane sleeve near the annular confined regeneration chamber, and then flows into the annular confined regeneration chamber for discharge. In this way, the weak deposit layer on the surface of the cation exchange membrane sleeve is stripped off and the residual complex-breaking regulator is diluted in the non-stop circulation state.

[0017] The beneficial effects of this invention are: 1. This invention sets up a central straight pipe and an annular confined regeneration chamber within a coaxial diversion confined regeneration cylinder, and uses a contamination load detection component and a rotating diversion valve core to adjust the flow ratio of the two paths according to the overall contamination load of the cleaning fluid. When the overall contamination load is low, a larger proportion of the cleaning fluid passes through the central straight pipe in a short distance. When the overall contamination load increases, the proportion of the cleaning fluid entering the annular confined regeneration chamber is increased and enhanced treatment is performed. This avoids the overtreatment problems caused by traditional full-volume complex breaking, full-volume electrochemical treatment, or full-volume resin adsorption, and reduces the consumption of reagents, electricity, and resin capacity.

[0018] 2. This invention concentrates the spiral confinement guide plate, the slow-release complex-breaking ring, and the membrane electromigration trapping assembly in the annular confinement regeneration chamber. This allows the cleaning liquid entering the annular confinement regeneration chamber to first form a spiral mixture in the same confinement path, and then undergo non-precipitation complex breaking, followed by membrane electromigration trapping of metal ions. This avoids the complexed metal directly impacting the polishing resin column or membrane unit, and improves the stability of metal contaminant trapping.

[0019] 3. This invention mixes the cleaning solution that passes through the central straight pipe in a short distance with the cleaning solution treated in the annular confined regeneration chamber through a back-mixing stabilization chamber. Under low pollution load conditions, the cleaning solution that has passed through the central straight pipe in a short distance and has not undergone complex-breaking chemical dosing is used to perform reverse pulse sweeping on the cation exchange membrane sleeve through a pulse back-sweep branch. This allows the weak deposited layer on the membrane surface to be peeled off without stopping the machine, while diluting the residual complex-breaking regulator. This reduces membrane fouling and resin oxidation damage, and improves the continuous operation stability of the circulating treatment device. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the overall recycling processing device of the present invention; Figure 2 This is a schematic cross-sectional view of the coaxial flow-diverting confined regeneration cylinder of the present invention. Figure 3 This is a schematic diagram of the cooperative structure of the rotary diverter valve core, the central straight pipe, and the annular confined regeneration chamber of the present invention. Figure 4 This is a schematic diagram of the cooperative structure of the spiral confining guide plate and the slow-release complex-breaking ring of the present invention; Figure 5 This is a schematic diagram of the structure of the diaphragm electromigration trapping assembly of the present invention; Figure 6 This is a schematic diagram of the connection structure between the remixing and stabilizing cavity, the ORP buffer filler layer, and the polishing resin column of the present invention. Figure 7 This is a schematic diagram of the connection structure of the pulse retrace branch of the present invention; Figure 8 This is a schematic flowchart of the cyclic processing method of the present invention.

[0022] The diagram is marked as follows: 1. Cleaning tank; 2. Collection tank; 3. Inlet pipe; 4. Circulation pump; 5. Pre-filter; 6. Coaxial diversion and confined regeneration cylinder; 7. Outer cylinder; 8. Central straight pipe; 9. Annular confined regeneration chamber; 10. Rotary diversion valve core; 11. Straight diversion port; 12. Regeneration diversion port; 13. Spiral confined guide plate; 14. Slow-release complex-breaking ring; 15. Diaphragm electromigration trapping assembly; 16. Anode isolation sleeve; 17. Anode component; 18. Cation exchange membrane sleeve; 19. Cathode enrichment cylinder; 20. Metal enrichment chamber; 21. Remixing and stabilizing chamber; 22. ORP buffer packing layer; 23. Polishing resin column; 24. Return pipe; 25. Concentrate circulation discharge pipe; 26. Pollution load detection assembly; 27. Controller; 28. Pulse retracement branch. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0024] It should be noted that, unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0025] like Figures 1 to 8As shown, a circulating treatment device for electroplating cleaning solution of printed circuit boards includes a cleaning tank 1, a collection tank 2, an inlet pipe 3, a circulating pump 4, a pre-filter 5, a coaxial diversion and confinement regeneration cylinder 6, and a return pipe 24. The cleaning tank 1 is located at the water washing station of the printed circuit board electroplating line and is used to hold the cleaning solution required for cleaning the circuit boards after electroplating. An outlet is provided on the lower side or bottom of the cleaning tank 1, and the outlet is connected to the collection tank 2 through a pipeline. The collection tank 2 is used to receive the cleaning solution from the cleaning tank 1 and to manage the flow fluctuations and concentration caused by the batch entry and exit of circuit boards. The temperature fluctuation is initially buffered. A circulation pump 4 is installed at the outlet of the collection tank 2 to discharge the liquid. A pre-filter 5 is installed at the rear end of the circulation pump 4. The circulation pump 4 is preferably an acid and alkali resistant magnetic pump, a corrosion resistant centrifugal pump or a diaphragm pump. The circulation flow rate of the circulation pump 4 can be set to 1 to 5 times the effective volume of the cleaning tank 1 per hour. The pre-filter 5 can be a bag filter, a cartridge filter or a basket filter. The filtration accuracy is preferably 5μm to 50μm. It is used to intercept copper powder, resin powder, dry film fragments, glass fiber particles and other suspended impurities in the cleaning liquid.

[0026] The coaxial diversion and confinement regeneration cylinder 6 is located between the pre-filter 5 and the return pipe 24, and is the core structure that distinguishes this invention from conventional cleaning fluid circulation treatment systems. The coaxial diversion and confinement regeneration cylinder 6 includes an outer cylinder 7, a central straight pipe 8, an annular confinement regeneration chamber 9, a rotary diversion valve core 10, a spiral confinement guide plate 13, a slow-release complex-breaking ring 14, a diaphragm electromigration trapping assembly 15, and a remixing and stabilizing chamber 21.

[0027] The outer cylinder 7 is a vertical cylindrical structure and can be made of polypropylene, polyvinylidene fluoride, fiberglass, or stainless steel lined with fluoroplastics. The lower end of the outer cylinder 7 is the liquid inlet and the upper end is the liquid outlet. The central straight pipe 8 is set along the central axis of the outer cylinder 7. The lower end of the central straight pipe 8 corresponds to the rotary diversion valve core 10, and the upper end of the central straight pipe 8 is connected to the return mixing and stabilizing chamber 21. The central straight pipe 8 is used to allow a larger proportion of the cleaning fluid to pass through short distances when the overall pollution load of the cleaning fluid is low or when it is in a low-load operating condition, so that this part of the cleaning fluid does not pass through the complex-breaking dosing and electromigration collection areas, thereby reducing unnecessary treatment intensity.

[0028] The annular confined regeneration chamber 9 is formed between the inner wall of the outer cylinder 7 and the outer wall of the central straight pipe 8. The annular confined regeneration chamber 9 is not an ordinary bypass pipe, but a treatment space used to receive a larger proportion of the cleaning fluid and perform confined regeneration when the overall contamination load of the cleaning fluid increases. The so-called confined means that the cleaning fluid entering the annular confined regeneration chamber 9 is restricted to a smaller flow channel cross section and a longer spiral path, so that it can complete mixing, complex breaking and metal migration capture in a short time, instead of entering a large external reaction tank or a long-process concentration system.

[0029] like Figure 3As shown, the rotary diverter valve core 10 is rotatably mounted on the inlet end of the outer cylinder 7; the rotary diverter valve core 10 has a straight diverter port 11 and a regeneration diverter port 12; the straight diverter port 11 is connected to the central straight pipe 8, and the regeneration diverter port 12 is connected to the annular confined regeneration chamber 9; the straight diverter port 11 and the regeneration diverter port 12 are staggered along the circumference of the rotary diverter valve core 10, so that the rotary diverter valve core 10 can form a proportional change of opening and closing or large and small when it rotates.

[0030] When the rotary diversion valve core 10 rotates in the first direction, the opening of the straight diversion port 11 increases and the opening of the regeneration diversion port 12 decreases; when the rotary diversion valve core 10 rotates in the second direction, the opening of the regeneration diversion port 12 increases and the opening of the straight diversion port 11 decreases; through this structure, the cleaning fluid is not all sent into the same treatment path, but is dynamically distributed between the central straight pipe 8 and the annular confined regeneration chamber 9 according to the contamination load.

[0031] A contamination load detection component 26 is provided at the inlet end of the coaxial diversion and confinement regeneration cylinder 6. The contamination load detection component 26 may include at least two of the following: conductivity detector, pH / ORP detector, and UV absorption detector. The conductivity detector is used to determine the accumulation trend of salt and metal salt in the cleaning solution, the pH / ORP detector is used to determine the acidity, alkalinity, and redox state of the cleaning solution, and the UV absorption detector can be used to assist in determining the load of organic complexing agents or brightener decomposition products. The contamination load detection component 26 is electrically connected to the controller 27, and the controller 27 is electrically connected to the rotary diversion valve core 10, the slow-release complex-breaking ring 14, and the diaphragm electromigration trapping component 15, respectively.

[0032] In a preferred embodiment, the controller 27 does not physically sort the cleaning fluid entering the coaxial diversion confined regeneration chamber 6, but dynamically adjusts the flow ratio between the central straight pipe 8 and the annular confined regeneration chamber 9 based on the overall contamination load of the cleaning fluid detected by the contamination load detection component 26. Specifically, the controller 27 can calculate the contamination load index L based on at least two parameters among conductivity, pH value, ORP value, and UV254 absorbance. The contamination load index L can be determined as follows: when the conductivity, UV254 absorbance, or metal ion concentration increases relative to a set reference value, or when the pH / ORP deviates from a set operating range, the contamination load index L increases. The controller 27 has preset thresholds T1, T2, and a drop threshold T0, where T0 is less than or equal to T1, and T1 is less than T2. ​​When L < T1, the controller 27 determines that the overall contamination load of the cleaning fluid is low, and drives the rotating diversion valve core 10 to open the direct diversion port 11 to 70%–100% and the regeneration diversion port 12 to open to 0%–30%, so that a larger proportion of the cleaning fluid enters the remixing and stabilizing chamber 21 directly without passing through the slow-release complex-breaking ring 14 and the diaphragm electromigration trapping assembly 15. When T When L ≤ T2, the controller 27 opens the direct-flow diversion port 11 to 40%–70% and the regeneration diversion port 12 to 30%–60%, allowing some of the cleaning fluid to enter the annular confined regeneration chamber 9 for confined complex breaking and electromigration trapping. When L ≥ T2, the controller 27 opens the direct-flow diversion port 11 to 0%–40% and the regeneration diversion port 12 to 60%–100%, and simultaneously increases the dosage of the slow-release complex breaking ring 14 and the operating current or pulse duty cycle of the diaphragm electromigration trapping assembly 15. Therefore, the low contamination load state and high complexing load state referred to in this invention refer to the operating condition judgment made by the controller 27 based on the overall contamination load of the cleaning fluid before entering the device, rather than the cleaning fluid entering the device at the same time being separated into two liquids with different contamination concentrations at the inlet end.

[0033] like Figure 4 As shown, the spiral confining guide plate 13 is disposed in the annular confining regeneration chamber 9; the inner edge of the spiral confining guide plate 13 is fixedly connected to the outer wall of the central straight pipe 8, and a flow guiding gap is formed between the outer edge of the spiral confining guide plate 13 and the inner wall of the outer cylinder 7; the flow guiding gap can be 2mm to 8mm, and the pitch of the spiral confining guide plate 13 can be 1.2 to 3 times the radial width of the annular confining regeneration chamber 9; the cleaning fluid entering the annular confining regeneration chamber 9 spirals upward along the outer periphery of the central straight pipe 8 under the action of the spiral confining guide plate 13, forming a spiral shear flow; this flow mode extends the residence path of the cleaning fluid entering the annular confining regeneration chamber 9 on the one hand, and enables the complex-breaking regulator released by the slow-release complex-breaking ring 14 to be quickly entrained and dispersed on the other hand, avoiding the accumulation of the agent in local areas.

[0034] The slow-release complex-breaking ring 14 is disposed on the liquid inlet side of the annular confined regeneration chamber 9, and preferably located between the first and third turns of the spiral confined guide plate 13; the slow-release complex-breaking ring 14 can be an annular microporous tube, with multiple drug outlet holes evenly distributed along the circumference of the annular microporous tube, and the drug outlet holes are arranged facing the liquid-facing surface of the spiral confined guide plate 13; the slow-release complex-breaking ring 14 is connected to an external small-flow metering pump through a corrosion-resistant dosing pipe; the complex-breaking regulator released by the slow-release complex-breaking ring 14 is a non-precipitated complex-breaking regulator, and its purpose is not to form a large amount of metal hydroxide or metal sulfide precipitate in the annular confined regeneration chamber 9, but to convert complexed metal pollutants such as copper, nickel or tin into electromigrable free or weakly complexed metal ions.

[0035] In one embodiment, when the cleaning solution to be treated mainly contains copper ammonia complexes or copper organic complexes, the non-precipitating complex-breaking regulator can be persulfate, hydrogen peroxide, or a combination of the former with a weak acid pH adjuster, so that the pH value in the annular confined regeneration chamber 9 is controlled within the range of 2.5 to 5.5. This pH range can weaken the stability of some complexes and avoid a large amount of copper hydroxide precipitating and clogging in the annular confined regeneration chamber 9. For cleaning solutions containing nickel complexes, persulfate can also be used to assist weak acid in breaking the complexes, so that the complexed nickel is converted into nickel ions that are more easily migrated or in a weakly complexed nickel state. The types and concentrations of the above-mentioned agents can be adjusted according to the specific electroplating system. This invention emphasizes the continuous coordination between non-precipitating complex breaking and subsequent diaphragm electromigration capture.

[0036] like Figure 5 As shown, the diaphragm electromigration trapping assembly 15 is located in the downstream section of the annular confined regeneration chamber 9; the diaphragm electromigration trapping assembly 15 includes an anode isolation sleeve 16, an anode element 17, a cation exchange membrane sleeve 18, a cathode enrichment cylinder 19, and a metal enrichment chamber 20; the anode isolation sleeve 16 is located on one side of the annular confined regeneration chamber 9, and the anode element 17 is located inside the anode isolation sleeve 16; an independent anolyte is introduced into the anode isolation sleeve 16 so that the anode element 17 does not directly contact the cleaning solution in the annular confined regeneration chamber 9.

[0037] The purpose of this design is to reduce the direct chlorine evolution or generation of strong oxidizing byproducts in the anode area of ​​the cleaning solution when the printed circuit board electroplating cleaning solution contains chloride ions, thus preventing these byproducts from returning to the cleaning tank 1 through the return pipe 24 and affecting the cleaning quality of the circuit board.

[0038] A cation exchange membrane sleeve 18 is disposed between the annular confined regeneration chamber 9 and the metal enrichment chamber 20; a cathode enrichment cylinder 19 is disposed inside the metal enrichment chamber 20, and the cathode enrichment cylinder 19 can be a titanium mesh, graphite mesh, stainless steel mesh, or conductive carbon fiber mesh; during operation, the anode element 17 and the cathode enrichment cylinder 19 are respectively connected to a DC power supply or a pulsed DC power supply. The metal ions treated by the slow-release complex-breaking ring 14 migrate to the metal enrichment chamber 20 through the cation exchange membrane sleeve 18 under the action of the electric field, and are enriched or electrodeposited and captured near the cathode enrichment cylinder 19; since the part of the cleaning liquid that enters the diaphragm electromigration capture assembly 15 is distributed by the rotating diversion valve core 10 according to the pollution load ratio, rather than all the circulating cleaning liquid, the electromigration treatment volume is smaller and the treatment intensity is more concentrated.

[0039] In one specific operating mode, the diaphragm electromigration trapping assembly 15 further includes a DC power supply or a pulsed DC power supply. The anode element 17 is electrically connected to the positive terminal of the DC power supply or the pulsed DC power supply, and the cathode enrichment cylinder 19 is electrically connected to the negative terminal of the DC power supply or the pulsed DC power supply. The cation exchange membrane sleeve 18 is located between the annular confined regeneration chamber 9 and the metal enrichment chamber 20, allowing copper, nickel, or tin metal ions treated with a non-precipitating complex-breaking regulator to migrate from the annular confined regeneration chamber 9 side through the cation exchange membrane sleeve 18 to the metal enrichment chamber 20 side under the action of an electric field. An independent anolyte is introduced into the anode isolation sleeve 16. The anolyte can be sodium sulfate, sulfuric acid, or a weakly acidic conductive liquid. The anolyte is isolated from the cleaning solution in the annular confined regeneration chamber 9 to reduce the risk of chlorine-containing cleaning solution generating chlorine gas or strong oxidizing byproducts in the anode area. The operating voltage of the diaphragm electromigration trapping component 15 can be 5V to 36V, preferably 12V to 24V; the electric field strength between electrodes can be 2V / cm to 12V / cm, preferably 4V / cm to 8V / cm; the operating current density can be 5mA / cm² to 80mA / cm², preferably 10mA / cm² to 40mA / cm²; in pulsed DC mode, the pulse frequency can be 0.1Hz to 10Hz, and the duty cycle can be 30% to 80%. Under a set of simulated operating conditions, the effective volume of the cleaning tank 1 is 500L, the circulation flow rate of the circulating pump 4 is 1000L / h, the filtration accuracy of the pre-filter 5 is 10μm, the effective residence time of the annular confined regeneration chamber 9 is 3min to 5min, and the cleaning solution to be treated is a copper-containing complexed cleaning solution. When the overall contamination load of the cleaning solution is lower than the first preset threshold, about 75% to 90% of the circulating solution passes through the central straight pipe 8 in a short distance. When the overall contamination load of the cleaning solution reaches the second preset threshold, about 65% to 85% of the circulating solution enters the annular confined regeneration chamber 9. Compared with full-volume complex breaking and full-volume electromigration treatment methods, under the condition that the total copper concentration in the effluent is controlled below 0.5 mg / L, the consumption of complex breaking regulator is reduced by approximately 25%–40%, the power consumption is reduced by approximately 20%–35%, and the operating time for the polishing resin column 23 to reach the breakthrough concentration is extended by approximately 30%–60%. Compared with the operation mode without the pulse backsweep branch 28, the increase in pressure difference on the inlet side of the cation exchange membrane sleeve 18 is reduced by approximately 20%–35% after 72 hours of continuous operation. The above operating data indicate that, based on the proportionate diversion control of the overall pollution load, combined with the confined complex breaking, electromigration capture, and back-mixing stabilization structure, it is possible to reduce the chemical consumption, power consumption, and end-resin load caused by full-volume enhanced treatment without interrupting the online circulation and reuse of the cleaning solution.

[0040] The metal enrichment chamber 20 is connected to the concentrated liquid circulation discharge pipe 25; a small flow circulation pump, an intermittent discharge valve, and a sampling port can be installed on the concentrated liquid circulation discharge pipe 25; the enriched liquid in the metal enrichment chamber 20 can be circulated and concentrated within a certain period of time. When the metal ion concentration reaches the preset concentration, it is discharged through the concentrated liquid circulation discharge pipe 25 and enters the subsequent metal recovery or centralized treatment process; compared with dispersing heavy metals in a large amount of cleaning liquid, the present invention transfers metal pollutants to a small volume of concentrated liquid through the metal enrichment chamber 20, which helps to reduce the burden of subsequent treatment.

[0041] like Figure 6 As shown, the remixing and stabilizing chamber 21 is located at the liquid outlet end of the coaxial diversion and confined regeneration cylinder 6; the liquid outlet ends of the central straight pipe 8 and the annular confined regeneration chamber 9 are both connected to the remixing and stabilizing chamber 21; the remixing and stabilizing chamber 21 can be configured as an enlarged cavity at the top of the outer cylinder 7, with a cross-sectional area greater than the sum of the liquid outlet cross-sectional areas of the central straight pipe 8 and the annular confined regeneration chamber 9; a baffle structure can be provided inside the remixing and stabilizing chamber 21 to ensure that the cleaning fluid passing through the central straight pipe 8 in a short distance is fully mixed with the cleaning fluid after confined regeneration in the annular confined regeneration chamber 9.

[0042] An ORP buffer packing layer 22 is installed inside the remixing and stabilizing chamber 21. The ORP buffer packing layer 22 can be made of activated carbon fiber, reducing resin, inert catalytic decomposition packing, or other packing that can reduce the influence of residual oxidizing substances. The ORP buffer packing layer 22 is located between the liquid outlet of the annular confined regeneration chamber 9 and the polishing resin column 23. Since a non-precipitated complex-breaking regulator is released in the annular confined regeneration chamber 9, if residual oxidizing substances directly enter the polishing resin column 23, it may accelerate resin aging. By setting the ORP buffer packing layer 22, the influence of residual complex-breaking regulator on the polishing resin column 23 can be further weakened after remixing. The polishing resin column 23 is located between the mixing and stabilizing chamber 21 and the return liquid pipe 24. The polishing resin column 23 can be filled with chelating resin, weakly acidic cation exchange resin or mixed bed resin to adsorb residual trace metal ions. Since part of the cleaning liquid entering the annular confined regeneration chamber 9 has already completed non-precipitation complex breaking and diaphragm electromigration capture in the annular confined regeneration chamber 9, the polishing resin column 23 mainly undertakes the end polishing function, and together with the front-end proportional diversion control, it reduces the impact load of all complexed metals, which is beneficial to extending the service life of the polishing resin column 23.

[0043] like Figure 7As shown, a pulse backsweep branch 28 is provided between the back-mixing and stabilizing chamber 21 and the rear section of the annular confined regeneration chamber 9. One end of the pulse backsweep branch 28 is connected to the back-mixing and stabilizing chamber 21, and the other end is connected to the area of ​​the annular confined regeneration chamber 9 near the cation exchange membrane sleeve 18. A small corrosion-resistant pulse pump or solenoid valve can be installed on the pulse backsweep branch 28 and electrically connected to the controller 27. When the cleaning fluid pollution load decreases and continues for a certain period of time, the controller 27 can open the pulse backsweep branch 28, so that the cleaning fluid in the back-mixing and stabilizing chamber 21 that has passed through the central straight pipe 8 for a short distance and has not undergone complex-breaking dosing can be reverse pulsed across the side of the cation exchange membrane sleeve 18 near the annular confined regeneration chamber 9. This part of the cleaning fluid has not undergone complex-breaking dosing and is in a low overall pollution load operating condition. Its metal ion concentration and residual complex-breaking agent concentration are both low. When the reverse pulse passes through the membrane surface, it can peel off the weak deposit layer on the membrane surface and dilute the residual complex-breaking regulator in the rear section of the annular confined regeneration chamber 9.

[0044] During operation, when the contamination load detection component 26 detects that the overall contamination load of the cleaning fluid is low, the controller 27 drives the rotary diversion valve core 10 to increase the opening of the straight diversion port 11 and decrease the opening of the regeneration diversion port 12. At this time, a larger proportion of the cleaning fluid enters the central straight pipe 8 and passes through it briefly. When the contamination load detection component 26 detects that the overall contamination load of the cleaning fluid is high, the controller 27 drives the rotary diversion valve core 10 to rotate in the opposite direction, increasing the opening of the regeneration diversion port 12 and increasing the proportion of cleaning fluid entering the annular confined regeneration chamber 9. At the same time, the controller 27 can increase the dosage of the slow-release complex-breaking ring 14 and increase the operating current or pulse duty cycle of the diaphragm electromigration trapping component 15 to match the treatment intensity with the overall contamination load of the cleaning fluid.

[0045] The cyclic processing method of the present invention is as follows: First, after the printed circuit board enters the cleaning tank 1 from the electroplating tank, the electroplating solution carried on the board surface enters the cleaning solution. The cleaning solution gradually contains metal ions such as copper, nickel, and tin, complexing agents, brightener decomposition products, and a small amount of suspended particles. The cleaning solution in the cleaning tank 1 enters the collection tank 2, which buffers the water volume and concentration. After the circulation pump 4 starts, the cleaning solution in the collection tank 2 is sent to the pre-filter 5. After the pre-filter 5 removes suspended particles, the cleaning solution enters the coaxial diversion and confinement regeneration cylinder 6.

[0046] Subsequently, the contamination load detection component 26 detects the state of the cleaning fluid before it enters the coaxial diversion confinement regeneration cylinder 6. When the detection results show that the conductivity, UV absorbance, and pH / ORP changes of the cleaning fluid are all within the preset range, the controller 27 determines that the overall contamination load of the cleaning fluid is low and drives the rotating diversion valve core 10 to make the opening of the straight diversion port 11 greater than the opening of the regeneration diversion port 12. At this time, a larger proportion of the cleaning fluid enters the central straight pipe 8 and directly enters the back mixing and stabilizing chamber 21 along the central straight pipe 8. This part of the cleaning fluid does not pass through the slow-release complex-breaking ring 14 and the diaphragm electromigration trapping component 15, thereby avoiding excessive dosing and excessive electrochemical treatment.

[0047] When the amount of liquid carried out by the circuit board increases, and the load of complexed metal contaminants or organic additives in the cleaning solution increases, the contamination load detection component 26 detects an increase in conductivity, an increase in UV absorption value, or a change in pH / ORP status. The controller 27 determines that the overall contamination load of the cleaning solution has increased and drives the rotating diversion valve core 10 to increase the opening of the regeneration diversion port 12. At this time, the proportion of cleaning solution entering the annular confined regeneration chamber 9 increases. The cleaning solution entering the annular confined regeneration chamber 9 spirals upward along the outer periphery of the central straight pipe 8 under the guidance of the spiral confined guide plate 13, forming continuous disturbance and shear mixing.

[0048] During the spiral flow process, the slow-release complex-breaking ring 14 releases a non-precipitating complex-breaking regulator into the cleaning fluid. Since the outlet hole is set towards the liquid-facing surface of the spiral confining guide plate 13, the complex-breaking regulator is quickly entrained and dispersed by the cleaning fluid entering the annular confining regeneration chamber 9, making it less likely to cause the problem of excessively high local agent concentration. Complexed copper, nickel, or tin metal contaminants are converted into free or weakly complexed metal ions that are more easily electromigrated under the action of the non-precipitating complex-breaking regulator, and enter the diaphragm electromigration trapping component 15 with the water flow.

[0049] In the diaphragm electromigration trapping assembly 15, the anode element 17 is located inside the anode isolation sleeve 16, the cathode enrichment cylinder 19 is located inside the metal enrichment cavity 20, and the cation exchange membrane sleeve 18 is disposed between the annular confined regeneration cavity 9 and the metal enrichment cavity 20. After energization, the metal ions in the annular confined regeneration cavity 9 pass through the cation exchange membrane sleeve 18 under the action of the electric field and enter the metal enrichment cavity 20, and are enriched or electrodeposited near the cathode enrichment cylinder 19. The enriched solution in the metal enrichment cavity 20 is intermittently discharged through the concentrated solution circulation discharge pipe 25.

[0050] The cleaning solution that passes through the central straight pipe 8 in a short distance is mixed with the cleaning solution that has been treated by the annular confined regeneration chamber 9 in the remixing and stabilizing chamber 21. The mixed cleaning solution passes through the ORP buffer packing layer 22 to reduce the impact of residual non-precipitated complex-breaking regulator on the subsequent polishing resin column 23. It then enters the polishing resin column 23 to remove residual trace metal ions. The polished cleaning solution is returned to the cleaning tank 1 through the return pipe 24 and is used for cleaning after electroplating of printed circuit boards.

[0051] Furthermore, when the contamination load detection component 26 detects that the contamination load of the cleaning fluid is below the fallback threshold and remains so for a preset time, the controller 27 executes a low-load self-cleaning backflush step. At this time, the controller 27 suspends the dosing of the slow-release complex-breaking ring 14, keeps the straight-through diversion port 11 at a large opening, and makes the regeneration diversion port 12 open and close slightly at a cycle of 0.5s to 5s. At the same time, the operating current of the diaphragm electromigration trapping component 15 is reduced, and the pulse backflush branch 28 is opened, so that the cleaning fluid that has passed through the central straight-through pipe 8 in the back-mixing stabilization chamber 21 without undergoing complex-breaking dosing is returned to the cleaning fluid dosing. A reverse pulse sweep passes through the side of the cation exchange membrane sleeve 18 near the annular confined regeneration chamber 9. Since this cleaning solution has not undergone complex-breaking and metal enrichment treatment, and is operating under conditions of low overall fouling load, its metal ion concentration is low. It can peel off the weak deposited layer on the membrane surface without introducing additional cleaning agents, and at the same time dilute the residual complex-breaking regulator in the rear section of the annular confined regeneration chamber 9. This step uses the short-path reflux water generated by the low fouling load operation itself as the membrane surface cleaning medium, avoiding the circulation interruption caused by traditional shutdown acid washing or separate backwashing.

[0052] In one specific embodiment, the effective volume of the cleaning tank 1 is 500L, the flow rate of the circulating pump 4 is 1000L / h, and the filtration accuracy of the pre-filter 5 is 10μm; the inner diameter of the outer cylinder 7 of the coaxial diversion confined regeneration cylinder 6 is 160mm~220mm, the inner diameter of the central straight pipe 8 is 50mm~80mm, and the effective height of the annular confined regeneration chamber 9 is 600mm~1200mm; the pitch of the spiral confined guide plate 13 is 60mm~150mm, and the effective residence time of the cleaning liquid in the annular confined regeneration chamber 9 is 1min~8min; the operating voltage of the diaphragm electromigration trapping assembly 15 is 5V~36V, or the electric field strength between the electrodes is 2V / cm~12V / cm; the above parameters are only examples, and those skilled in the art can adjust them according to the volume of the cleaning tank 1, the plating type, the requirements of the cleaning water quality, and the production cycle.

[0053] It is important to emphasize that this invention does not simply connect units such as filtration, complex breaking, electrolysis, and resin adsorption in series. Instead, it constructs two circulation paths with different treatment intensities but unified remixing at the outlet within the same coaxial diversion confined regeneration cylinder 6. The central straight pipe 8 is used to allow a larger proportion of the cleaning fluid to pass through short distances when the overall pollution load of the cleaning fluid is low. The annular confined regeneration chamber 9 is used to receive a larger proportion of the cleaning fluid and perform confined regeneration when the overall pollution load of the cleaning fluid increases. The rotary diversion valve core 10 is used to change the flow ratio of the two paths according to the overall pollution load of the cleaning fluid. The spiral confined guide plate 13, the slow-release complex breaking ring 14, and the diaphragm electromigration trapping assembly 15 are used to complete complex breaking and metal trapping within a small confined space. The remixing and stabilizing chamber 21 is used to reduce water quality fluctuations caused by different treatment paths before returning to the cleaning tank 1. The pulse backsweep branch 28 uses short-distance backflow water during the low pollution load stage to perform non-stop backsweeping of the membrane surface. The above structures have clear functional relationships and revolve around the core issue of "online matching treatment under pollution load fluctuations".

[0054] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples. Within the framework of this invention, technical features of the above embodiments or different embodiments can be combined. The driving method of the rotary diversion valve core 10, the pitch of the spiral confining guide plate 13, the orifice diameter of the slow-release complex-breaking ring 14, the material of the cation exchange membrane sleeve 18, the material of the cathode enrichment cylinder 19, the sensor combination of the pollution load detection component 26, and the opening and closing cycle of the pulse retrace branch 28 can all be equivalently replaced according to specific operating conditions. Any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the protection scope of this invention.

Claims

1. A circulating treatment device for electroplating cleaning solution of printed circuit boards, comprising a controller (27), a cleaning tank (1), a collection tank (2) communicating with the cleaning tank (1), an inlet pipe (3) disposed between the collection tank (2) and the cleaning tank (1), a circulating pump (4) disposed at the outlet end of the collection tank (2), a pre-filter (5), a polishing resin column (23), and a return pipe (24), characterized in that, It also includes a coaxial diversion confined regeneration cylinder (6), which is disposed between the pre-filter (5) and the polishing resin column (23). The coaxial diversion confined regeneration cylinder (6) includes an outer cylinder (7), a central straight pipe (8) arranged along the axial direction of the outer cylinder (7), and an annular confined regeneration chamber (9) formed between the inner wall of the outer cylinder (7) and the outer wall of the central straight pipe (8). The inlet end of the coaxial diversion confined regeneration cylinder (6) is provided with a rotary diversion valve core (10) and a pollution load detection component (26). The rotary diversion valve core (10) has a straight diversion port (11) connected to the central straight pipe (8) and a regeneration diversion port (12) connected to the annular confined regeneration chamber (9). The electroplating cleaning liquid in the cleaning tank (1) is introduced into the collection tank (2) through the inlet pipe (3) and then sent to the pre-filter (5) by the circulation pump (4). The pre-filtered cleaning liquid is then sent to the inlet end of the coaxial diversion confined regeneration cylinder (6). The annular confined regeneration chamber (9) is provided with a spiral confined flow guide plate (13), a slow-release complex-breaking ring (14), and a diaphragm electromigration trapping assembly (15) in sequence along the liquid flow direction. The coaxial diversion and confined regeneration cylinder (6) has a remixing and stabilizing chamber (21) at its outlet end. The central straight pipe (8) and the annular confined regeneration chamber (9) are both connected to the remixing and stabilizing chamber (21). The remixing and stabilizing chamber (21) is connected to the return pipe (24) via the polishing resin column (23). The other end of the return pipe (24) is connected to the cleaning tank (1). The contamination load detection component (26) is electrically connected to the controller (27). The controller (27) is electrically connected to the rotary diversion valve core (10), so that the controller (27) controls the overall cleaning fluid based on the contamination load detection component (26). The relative opening of the pollution load adjustment direct diversion port (11) and the regeneration diversion port (12) is adjusted; when the overall pollution load is lower than the first preset threshold, a large proportion of the cleaning fluid passes through the central direct pipe (8) in a short distance; when the overall pollution load reaches or exceeds the second preset threshold, the proportion of cleaning fluid entering the annular confined regeneration chamber (9) is increased, so that the cleaning fluid entering the annular confined regeneration chamber (9) is mixed with the liquid outflow from the central direct pipe (8) after being confined and broken down and electromigrated, and then flows back to the cleaning tank (1) through the polishing resin column (23) and the return pipe (24) in sequence.

2. The printed circuit board electroplating cleaning solution circulation treatment device according to claim 1, characterized in that, The rotary diverter valve core (10) is rotatably installed at the liquid inlet end of the outer cylinder (7). The straight diverter port (11) and the regeneration diverter port (12) are offset along the circumference of the rotary diverter valve core (10). When the rotary diverter valve core (10) rotates in the first direction, the opening of the straight diverter port (11) increases and the opening of the regeneration diverter port (12) decreases. When the rotary diverter valve core (10) rotates in the second direction, the opening of the regeneration diverter port (12) increases and the opening of the straight diverter port (11) decreases.

3. The printed circuit board electroplating cleaning solution circulation treatment device according to claim 1, characterized in that, The inner edge of the spiral confining guide plate (13) is fixedly connected to the outer wall of the central straight pipe (8), and a flow guiding gap is formed between the outer edge of the spiral confining guide plate (13) and the inner wall of the outer cylinder (7). The flow guiding gap is 2mm to 8mm, and the pitch of the spiral confining guide plate (13) is 1.2 to 3 times the radial width of the annular confining regeneration cavity (9).

4. The printed circuit board electroplating cleaning solution circulation treatment device according to claim 1, characterized in that, The slow-release complex-breaking ring (14) is an annular microporous tube with multiple drug outlet holes evenly distributed along the circumference. The drug outlet holes are set facing the liquid-facing surface of the spiral confinement guide plate (13). The slow-release complex-breaking ring (14) is used to release non-precipitated complex-breaking regulators to convert complexed copper, nickel or tin metal pollutants into electromigable free or weakly complexed metal ions.

5. The printed circuit board electroplating cleaning solution circulation treatment device according to claim 1, characterized in that, The membrane electromigration trapping assembly (15) includes a DC power supply or a pulsed DC power supply, an anode isolation sleeve (16), an anode component (17) disposed inside the anode isolation sleeve (16) and electrically connected to the positive electrode of the DC power supply or the pulsed DC power supply, a cation exchange membrane sleeve (18), a cathode enrichment cylinder (19) electrically connected to the negative electrode of the DC power supply or the pulsed DC power supply, and a metal enrichment cavity (20). The cation exchange membrane sleeve (18) is disposed between the annular confined regeneration cavity (9) and the cathode enrichment cylinder (19). The gap between the cation exchange membrane sleeve (18) and the cathode enrichment cylinder (19) forms the metal enrichment cavity (20). The metal enrichment cavity (20) is ion-selectively connected to the annular confined regeneration cavity (9) through the cation exchange membrane sleeve (18).

6. The printed circuit board electroplating cleaning solution circulation treatment device according to claim 5, characterized in that, An independent anolyte is introduced into the anode isolation sleeve (16), and the anode component (17) is isolated from the cleaning solution in the annular confined regeneration chamber (9). The metal enrichment chamber (20) is connected to a concentrated liquid circulation discharge pipe (25). One end of the concentrated liquid circulation discharge pipe (25) is connected to the metal enrichment chamber (20), and the other end is connected to an external metal recovery unit or a centralized processing unit. The concentrated liquid circulation discharge pipe (25) is equipped with an intermittent discharge valve, or a small flow circulation pump, an intermittent discharge valve, and a sampling port, for circulating and concentrating the metal enrichment liquid in the metal enrichment chamber (20) and discharging it intermittently.

7. The printed circuit board electroplating cleaning solution circulation treatment device according to claim 5, characterized in that, The back-mixing and stabilizing chamber (21) is formed at the liquid outlet end of the coaxial diversion and confined regeneration cylinder (6). An ORP buffer packing layer (22) is provided inside the back-mixing and stabilizing chamber (21) near the liquid outlet side. The liquid outlets of the central straight pipe (8) and the annular confined regeneration chamber (9) are first mixed in the back-mixing and stabilizing chamber (21) and then enter the polishing resin column (23) through the ORP buffer packing layer (22).

8. The printed circuit board electroplating cleaning solution circulation treatment device according to claim 7, characterized in that, A pulse backsweep branch (28) is provided between the back mixing and stabilizing chamber (21) and the rear section of the annular confined regeneration chamber (9). The pulse backsweep branch (28) is electrically connected to the controller (27). The pulse backsweep branch (28) is used to pulse the cleaning liquid that has passed through the central straight pipe (8) in the back mixing and stabilizing chamber (21) without undergoing complex-breaking and chemical dosing back to the rear section of the annular confined regeneration chamber (9) under low pollution load conditions.

9. A method for circulating a cleaning solution for electroplating on printed circuit boards, applied to the circulating cleaning solution device for electroplating on printed circuit boards as described in claim 8, characterized in that, Includes the following steps: S1. The electroplating cleaning solution in the cleaning tank (1) is introduced into the collection tank (2) through the inlet pipe (3), and then sent to the pre-filter (5) by the circulation pump (4). The suspended particles in the cleaning solution are intercepted by the pre-filter (5). S2. The pre-filtered cleaning solution is sent to the inlet end of the coaxial diversion and confinement regeneration cylinder (6), and the cleaning solution contamination load is detected by the contamination load detection component (26). S3. When the pollution load detection component (26) detects that the overall pollution load of the cleaning fluid is lower than the first preset threshold, the controller (27) drives the rotating diversion valve core (10) to make the opening of the straight diversion port (11) greater than the opening of the regeneration diversion port (12), so that a large proportion of the cleaning fluid enters the central straight pipe (8) and passes through in a short distance. S4. When the pollution load detection component (26) detects that the overall pollution load of the cleaning fluid reaches or exceeds the second preset threshold, the controller (27) drives the rotating diversion valve core (10) to increase the opening of the regeneration diversion port (12) and increase the proportion of cleaning fluid entering the annular confined regeneration chamber (9). The cleaning fluid entering the annular confined regeneration chamber (9) forms a spiral confined flow under the guidance of the spiral confined guide plate (13). S5, the slow-release complex-breaking ring (14) releases a non-precipitated complex-breaking regulator into the cleaning fluid entering the annular confined regeneration chamber (9), so that the complexed metal pollutants are converted into electromigrable free or weakly complexed metal ions. S6. The cleaning solution after breaking the complex enters the diaphragm electromigration trapping assembly (15). Metal ions migrate through the cation exchange membrane sleeve (18) to the metal enrichment chamber (20) and are enriched or electrodeposited by the cathode enrichment cylinder (19). S7. The cleaning fluid that passes through the central straight pipe (8) in a short distance is mixed with the cleaning fluid that has been treated by the annular confined regeneration chamber (9) in the back mixing and stabilizing chamber (21). After the mixed cleaning fluid is treated by the ORP buffer packing layer (22) and the polishing resin column (23), it is returned to the cleaning tank (1) through the return pipe (24).

10. The method for circulating the electroplating cleaning solution for printed circuit boards according to claim 9, characterized in that, After S7, when the contamination load detection component (26) detects that the cleaning fluid contamination load is lower than the fallback threshold and continues for a preset time, the controller (27) performs a low-load self-cleaning back scan step: suspends the addition of the slow-release complex-breaking ring (14), keeps the direct diversion port (11) at a large opening, and makes the regeneration diversion port (12) open and close slightly at a cycle of 0.5s to 5s, wherein the fallback threshold is less than or equal to the first preset threshold; At the same time, the operating current of the membrane electromigration trapping component (15) is reduced, and the pulse back scan branch (28) is turned on, so that the cleaning solution that has passed through the central straight tube (8) in the back mixing and stabilizing chamber (21) and has not been subjected to the complex-breaking drug is reverse pulsed across the side of the cation exchange membrane sleeve (18) near the annular confined regeneration chamber (9), and then flows into the annular confined regeneration chamber (9) and is discharged. In this way, the weak deposit layer on the surface of the cation exchange membrane sleeve (18) is peeled off and the residual complex-breaking regulator is diluted in the non-stop circulation state.

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