Ion exchange reaction device for recovering copper from circuit board micro-etching liquid

Abstract

The utility model relates to an ion exchange reaction device for recovering copper from circuit board micro-etching liquid, and relates to the technical field of recovering copper from micro-etching liquid, the reaction device comprises a resin column and an electrolysis mechanism, and the electrolysis mechanism comprises an electrolytic bath containing electrolyte for releasing copper ions from the resin column; the circulating assembly is used for discharging the electrolyte into the resin column and discharging the copper ions back into the electrolytic bath along with the electrolyte; and the collecting assembly is used for replacing copper ions in the electrolyte into copper in an electrochemical mode and collecting the copper. The copper ions in the micro-etching liquid are adsorbed through the resin column, and after the adsorption capacity of the resin column is saturated, the electrolyte is discharged into the resin column through the circulating assembly, so that the resin column releases the copper ions and recovers the adsorption capacity, and the copper ions in the micro-etching liquid are conveniently adsorbed again; and the released copper ions are discharged into the electrolytic bath, and the copper ions are replaced into copper through the collecting assembly and are collected, so that the recovery efficiency of the copper in the micro-etching liquid in the circuit board production process is improved, and a good environment-friendly effect is achieved.

Description

Technical Field

[0001] This application relates to the technical field of recovering copper from micro-etching solution, especially an ion exchange reaction device for recovering copper from printed circuit board (PCB) micro-etching solution. Background Art

[0002] The current technical status of recovering copper from PCB micro-etching solution refers to the technical application situation of effectively recovering the copper element contained in the micro-etching solution during the manufacturing and maintenance processes of circuit boards.

[0003] Currently, the technologies for recovering copper from PCB micro-etching solution mainly include two categories: physical methods and chemical methods. Physical methods mainly utilize the physical properties of copper, such as density and magnetism, to separate copper from the micro-etching solution. This method usually includes steps such as sedimentation, filtration, and magnetic separation. Its advantages are simple operation and low cost, but the recovery efficiency and purity are often limited to a certain extent. Chemical methods, on the other hand, convert the copper in the micro-etching solution into a form that is easy to separate and recover through chemical reactions. Commonly used chemical recovery technologies include displacement reaction, leaching reaction, and electrochemically deposition. These methods can usually achieve a relatively high copper recovery rate and good purity, but may require a relatively high initial investment and operating costs. At the same time, they may generate a certain amount of waste liquid and solid waste, which need to be further treated to meet environmental protection requirements.

[0004] Among them, the copper recovered by the electrolysis method in electrochemically precipitation has the advantage of high purity, so it is widely used. However, in the conventional electrolysis method for recovering copper, the copper ion concentration in the micro-etching solution is increased. After the copper ion concentration in the micro-etching solution reaches a certain level, the micro-etching solution is poured into a specified container, and then electricity is applied to conduct ion exchange on the copper ions in the micro-etching solution to displace the copper. However, this method requires the concentration of the micro-etching solution, resulting in high processing costs and complex operations. Therefore, there is an urgent need to design a copper recovery device that can improve the efficiency of copper recovery from the micro-etching solution during the PCB production process and has good environmental protection effects. Utility Model Content

[0005] In order to improve the efficiency of copper recovery from the micro-etching solution during the PCB production process and have good environmental protection effects, this application provides an ion exchange reaction device for recovering copper from PCB micro-etching solution.

[0006] The ion exchange reaction device for recovering copper from PCB micro-etching solution provided by this application adopts the following technical solutions:

[0007] The ion exchange reaction device for recovering copper from PCB micro-etching solution includes a resin column for adsorbing copper ions in the micro-etching solution. An electrolysis mechanism for removing copper ions in the resin column and restoring the adsorption capacity of the resin column is provided on the resin column. The electrolysis mechanism includes:

[0008] An electrolytic cell is provided at the bottom of the resin column, and an electrolytic solution is contained in the electrolytic cell to facilitate the release of copper ions from the resin column.

[0009] A circulation component is provided on the electrolytic cell and is used to drain the electrolytic solution into the resin column and drain the released copper ions back into the electrolytic cell along with the electrolytic solution.

[0010] A collection component is provided in the electrolytic cell and replaces the copper ions in the electrolytic solution with copper through an electrochemical method and collects it.

[0011] By adopting the above technical solution, the copper ions in the micro-etching solution are adsorbed by the resin column. When the adsorption capacity of the resin column is saturated, the circulation component drains the electrolytic solution into the resin column, enabling the resin column to release copper ions and restore its adsorption capacity, facilitating the re-adsorption of copper ions in the micro-etching solution. The released copper ions are drained into the electrolytic cell, and the collection component replaces the copper ions with copper and collects it, thereby improving the efficiency of copper recovery in the micro-etching solution during the production of printed circuit boards and having a good environmental protection effect.

[0012] Furthermore, the circulation component includes:

[0013] A feed pipe is provided in the electrolytic cell and the other end is provided on the top of the resin column.

[0014] A driving pump is provided on the electrolytic cell and is connected to the feed pipe. The driving pump is used to drain the electrolytic solution in the electrolytic cell into the resin column through the feed pipe.

[0015] A discharge pipe is provided at the end of the resin column away from the feed pipe. The discharge pipe is used to drain the electrolytic solution passing through the resin column into the electrolytic cell.

[0016] A first control valve is provided on the discharge pipe and is used to control the opening and closing of the discharge pipe.

[0017] By adopting the above technical solution, the driving pump drives the electrolytic solution to be drained into the resin column through the feed pipe. The copper ions in the resin column are released by the electrolytic solution. The first control valve opens the discharge pipe, and the electrolytic solution with copper ions is drained back into the electrolytic cell through the discharge pipe, thereby releasing the copper ions in the resin column and restoring the adsorption capacity of the resin column.

[0018] Furthermore, the collection component includes:

[0019] A power supply component is provided on the electrolytic cell and is used to provide power.

[0020] A positive electrode block is provided in the electrolytic cell and is electrically connected to the positive electrode of the power supply component.

[0021] An adsorption block, which is arranged in the electrolytic cell and electrically connected to the negative electrode of the power supply component, and is used for adsorbing and collecting the displaced copper.

[0022] A diaphragm plate, which is arranged in the electrolytic cell and divides the electrolytic cell, and the diaphragm plate allows ions to pass through.

[0023] By adopting the above technical solution, when the power supply component is energized, a closed circuit is formed through the positive electrode block, the electrolyte solution and the negative electrode block, so that the copper ions in the electrolyte solution are displaced into copper and adsorbed on the adsorption block, and the separator plate separates the positive and negative electrodes to prevent the direct reaction in the electrolytic cell from losing energy.

[0024] Furthermore, the adsorption block is a pure copper block, and the top of the adsorption block is detachably arranged in the electrolytic cell through a locking bolt.

[0025] By adopting the above technical solution, since the copper displaced by the copper ions is pure copper, it is adsorbed by the pure copper block, which is convenient for increasing the overall copper content. At the same time, as the adsorbed copper accumulates, the volume of the adsorption block continuously increases. When the adsorption block becomes large enough, the adsorption block can be replaced by loosening the bolt, improving the convenience of replacing the adsorption block.

[0026] Furthermore, the resin column includes:

[0027] A glass cylinder, which is tightly filled with a resin material for adsorbing copper ions in the micro-etching solution;

[0028] A sealing cover, which is arranged on the glass cylinder and used for sealing the opening of the glass cylinder, and the feeding pipe is arranged on the sealing cover;

[0029] An inlet pipe, which is arranged on the sealing cover and used for discharging the micro-etching solution into the glass cylinder;

[0030] A discharge pipe, which is arranged at one end of the glass cylinder far away from the sealing cover, and the discharge pipe is used for discharging the micro-etching solution after the copper ions are adsorbed by the resin material;

[0031] A second control valve, which is arranged on the discharge pipe and used for controlling the opening and closing of the discharge pipe.

[0032] By adopting the above technical solution, the micro-etching solution containing copper ions enters through the inlet pipe, and the resin material in the glass cylinder adsorbs and fixes the copper ions. The separated micro-etching solution is discharged through the discharge pipe, so as to adsorb and collect the copper ions.

[0033] Furthermore, a control board is arranged on the glass cylinder, and the control board controls the opening and closing of the first control valve and the second control valve according to the opening states of the inlet pipe and the feeding pipe.

[0034] By adopting the above technical solution, the control board controls the opening and closing of the first control valve through the opening states of the inlet pipe and the intake pipe, so as to facilitate the automatic switching of the resin column in different states.

[0035] Furthermore, a filter cylinder for preventing the escape of resin material is snap-fitted on the glass cylinder, and the filter cylinder is used for filtering the micro-etching solution or the electrolytic solution.

[0036] By adopting the above technical solution, the filter cylinder presses tightly against the resin, and the filter copper filters the micro-etching solution and the electrolytic solution entering the glass cylinder, preventing large-particle impurities from entering the resin material.

[0037] Furthermore, a one-way valve is arranged at one end of the feed pipe close to the sealing cover, and the one-way valve is used for preventing the micro-etching solution in the resin column from flowing into the feed pipe.

[0038] By adopting the above technical solution, the one-way valve is only used for the liquid to flow from the electrolytic cell into the resin column, so as to prevent the micro-etching solution in the resin column from flowing into the feed pipe.

[0039] In summary, the present application includes at least one of the following beneficial technical effects:

[0040] The resin column adsorbs copper ions in the micro-etching solution. When the adsorption capacity of the resin column is saturated, the feed pipe discharges the electrolytic solution into the resin column, enabling the resin column to release copper ions and restore the adsorption capacity, facilitating the re-adsorption of copper ions in the micro-etching solution. The released copper ions are discharged into the electrolytic cell and electrolyzed to convert the copper ions into copper and collect them, thereby improving the efficiency of copper recovery in the micro-etching solution during the production process of the circuit board and having a good environmental protection effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a schematic structural diagram of the reaction device of the present application;

[0042] Figure 2 is Figure 1 the sectional view taken along A-A in

[0043] Reference numerals: 1, resin column; 11, glass cylinder; 12, sealing cover; 13, inlet pipe; 14, discharge pipe; 15, second control valve; 16, filter cylinder; 2, electrolysis mechanism; 3, electrolytic cell; 4, circulation assembly; 41, feed pipe; 411, one-way valve; 42, driving pump; 43, discharge pipe; 44, first control valve; 5, collection assembly; 51, power supply component; 52, positive electrode block; 53, adsorption block; 54, diaphragm plate. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0044] The following is a further detailed description of the present application in conjunction with the attached Figure 1-2 drawings.

[0045] The embodiments of the present application disclose an ion exchange reaction device for recovering copper from a circuit board micro-etching solution.

[0046] Referring to Figure 1 , the ion exchange reaction device for recovering copper from a circuit board micro-etching solution includes a resin column 1 for adsorbing copper ions in the micro-etching solution, and an electrolysis mechanism 2 is provided on the resin column 1 to remove copper ions in the resin column 1 and restore the adsorption capacity of the resin column 1.

[0047] Referring to Figure 1 and Figure 2 , the resin column 1 includes a glass cylinder 11, a sealing cover 12, an inlet pipe 13, a discharge pipe 14 and a second control valve 15. The glass cylinder 11 is a cylindrical hollow cylinder, and a resin material for adsorbing copper ions in the micro-etching solution is tightly filled in the glass cylinder 11; after the resin material is filled, in order to prevent the resin material from escaping, a filter cylinder 16 is snap-fitted on the glass cylinder 11; the sealing cover 12 is threadedly installed on the glass cylinder 11, and the sealing cover 12 is used to only seal the upper opening of the glass cylinder 11; the inlet pipe 13 is fixedly installed on the sealing cover 12, and the inlet pipe 13 is used to discharge the micro-etching solution containing copper ions into the glass cylinder 11 through the inlet pipe 13, so that the copper ions in the micro-etching solution are in full contact and adsorption with the resin material, and the copper ions in the micro-etching solution are ion-exchanged by the resin material to ensure that the copper ions can be efficiently separated from the micro-etching solution and firmly fixed on the resin; at the same time, the filter cylinder 16 filters the incoming micro-etching solution.

[0048] Referring to Figure 1 and Figure 2 , the discharge pipe 14 is fixedly installed at the bottom of the glass cylinder 11 and is located at the end far from the sealing cover 12. The discharge pipe 14 is used to discharge the micro-etching solution after separating copper ions through the resin; the second control valve 15 is fixedly installed on the discharge pipe 14, and the second control valve 15 is used to control the opening or closing of the discharge pipe 14.

[0049] Referring to Figure 1 , by discharging the micro-etching solution into the glass cylinder 11 through the inlet pipe 13, the resin material continuously adsorbs the copper ions in the micro-etching solution, the second control valve 15 opens the discharge pipe 14, and finally the micro-etching solution after separating copper ions is discharged through the discharge pipe 14; as the resin continuously adsorbs copper ions, its adsorption capacity will gradually reach saturation.

[0050] Referring to Figure 1 , the electrolysis mechanism 2 includes an electrolytic cell 3 and a circulation component 4. The electrolytic cell 3 is located at the bottom of the resin column 1, and an electrolytic solution is contained in the electrolytic cell 3. The electrolytic solution can be used to release copper ions from the resin material.

[0051] Referring to Figure 1, the circulation component 4 is arranged on the electrolytic cell 3. The circulation component 4 is used to drain the electrolyte in the electrolytic cell 3 into the resin column 1. Through the electrolyte, copper ions are released from the resin material, and the released copper ions flow with the electrolyte and are drained back into the electrolytic cell 3. The circulation component 4 includes a feed pipe 41, a driving pump 42, a discharge pipe 43 and a first control valve 44. One end of the feed pipe 41 is fixedly installed in the electrolytic cell 3 and extends into the electrolyte. The other end of the feed pipe 41 is fixedly installed on the sealing cover 12. The feed pipe 41 is used to drain the electrolyte in the electrolytic cell 3 into the resin column 1. Among them, the filter cylinder 16 filters the incoming electrolyte. The driving pump 42 is fixedly installed on the electrolytic cell 3. The driving pump 42 is communicated with the feed pipe 41. The driving pump 42 is used to drain the electrolyte in the electrolytic cell 3 into the resin column 1 through the feed pipe 41. Through the electrolyte, the copper ions on the resin material are released from the resin material, and at the same time, the resin material resumes the adsorption capacity for copper ions. The discharge pipe 43 is fixedly installed at one end of the resin column 1 away from the feed pipe 41. The discharge pipe 43 is used to drain the electrolyte passing through the resin column 1 and the copper ions in the electrolyte into the electrolytic cell 3, so as to drain the copper ions in the resin column 1 into the electrolytic cell 3. The first control valve 44 is fixedly installed on the discharge pipe 43. The first control valve 44 is used to control the opening and closing of the discharge pipe 43.

[0052] Refer to Figure 1 , the electrolysis mechanism 2 further includes a collection component 5. The collection component 5 is arranged in the electrolytic cell 3 and replaces and collects the copper ions in the electrolyte by an electrochemical method. The collection component 5 includes a power supply part 51, a positive electrode block 52, an adsorption block 53 and a diaphragm plate 54. The power supply part 51 is fixedly installed on the electrolytic cell 3. The power supply part 51 is used to provide power. The positive electrode block 52 is fixedly installed in the electrolytic cell 3. The positive electrode block 52 is electrically connected to the positive electrode of the power supply part 51. The adsorption block 53 is arranged in the electrolytic cell 3. The adsorption block 53 is electrically connected to the negative electrode of the power supply part 51. Since the adsorption block 53 is used to adsorb the displaced copper, the adsorption block 53 is a pure copper block. The bottom of the adsorption block 53 is detachably installed in the electrolytic cell through a locking bolt. When the displaced copper reaches a certain amount, the adsorption block 53 and the adsorbed copper are taken out, and a new adsorption block 53 is replaced. The diaphragm plate 54 is fixedly installed in the electrolytic cell 3. The diaphragm plate 54 is used to divide the electrolytic cell 3. The diaphragm plate 54 allows ions to pass through. The diaphragm plate separates the positive and negative electrodes to prevent energy loss due to direct reaction in the electrolytic cell 3.

[0053] Refer to Figure 1 and Figure 2, after the adsorption capacity of the resin column 1 is restored, the driving pump 42 and the first control valve 44 are closed, and the inlet pipe 13 is opened to drain the copper ion-containing micro-etching solution into the resin column 1. To prevent the micro-etching solution in the resin column 1 from flowing back into the feed pipe 41, a one-way valve 411 is fixedly installed at one end of the feed pipe 41 close to the sealing cover 12. The one-way valve 411 is only used for the liquid to flow from the electrolytic cell 3 into the resin column 1 to prevent the micro-etching solution in the resin column 1 from flowing into the feed pipe 41.

[0054] Refer to Figure 1 , a control board is fixedly installed on the glass cylinder 11. The control board is electrically connected to the first control valve 44 and the second control valve 15. The control board controls the opening and closing of the first control valve 44 and the second control valve 15 according to the opening states of the inlet pipe 13 and the feed pipe 41; when the inlet pipe 13 is opened, the control board opens the second control valve 15 to open the discharge pipe 14; when the inlet pipe 13 is closed, the control board closes the second control valve 15 to close the discharge pipe 14; similarly, when the feed pipe is opened, the control board opens the first control valve 44 to open the discharge pipe 43; when the feed pipe is closed, the control board closes the first control valve 44 to close the discharge pipe 43.

[0055] Refer to Figure 1 and Figure 2 , the specific process is as follows:

[0056] S1: Open the inlet pipe 13 and the second control valve 15 to allow the copper ion-containing micro-etching solution to flow from the inlet pipe 13 into the resin column 1. The micro-etching solution is filtered through the filter cylinder 16, and then the copper ions in the micro-etching solution are ion-exchanged by the resin material to ensure that the copper ions can be efficiently separated from the micro-etching solution and firmly fixed on the resin material. Then the separated micro-etching solution is discharged from the discharge pipe 14 and reused after secondary treatment of the micro-etching solution to facilitate the recycling of the micro-etching solution.

[0057] S2: As the resin continuously adsorbs copper ions, its adsorption capacity gradually reaches saturation; then the inlet pipe 13 and the second control valve 15 are closed, and then the driving pump 42 is started and the first control valve 44 is opened to drain the electrolyte in the electrolytic cell 3 into the resin column 1 through the feed pipe 41. The copper ions are released from the resin material by the electrolyte, and the released copper ions flow with the electrolyte and finally are discharged back into the electrolytic cell 3 through the discharge pipe 43 to gradually restore the adsorption capacity of the resin column 1 and facilitate the reuse of the resin column 1.

[0058] S3: After the driving pump 42 is started, the power supply unit 51 is started, so that a closed circuit is formed among the positive electrode block 52, the electrolyte, and the adsorption block 53. Among them, copper ions gain electrons at the adsorption block 53 and are replaced by copper and adsorbed on the adsorption block 53. At the same time, copper ions flow in the direction of the adsorption block 53, and negative ions flow in the direction of the positive electrode block 52 and lose electrons at the positive electrode block 52. Eventually, the copper ions in the electrolyte are replaced by copper and adsorbed on the adsorption block 53, so as to realize the recovery of copper ions. At the same time, new electrolyte needs to be added during the electrolysis process.

[0059] S4: After the copper ions in the resin column 1 are completely released, the driving pump 42 and the first control valve 44 are closed. At the same time, the step S1 is repeated to realize the cyclic recovery of the micro-etching solution containing copper ions, improve the efficiency of copper recovery in the micro-etching solution during the production process of the circuit board, and have a good environmental protection effect.

[0060] The working principle of the embodiment of the present application is as follows:

[0061] The copper ions in the micro-etching solution are adsorbed by the resin column 1. After the adsorption capacity of the resin column 1 is saturated, the electrolyte is discharged into the resin column 1 through the feed pipe 41, so that the resin column 1 releases copper ions and restores the adsorption capacity, which is convenient for adsorbing the copper ions in the micro-etching solution again. The released copper ions are discharged into the electrolytic cell 3 and are replaced by copper and collected through electrolysis, so as to improve the efficiency of copper recovery in the micro-etching solution during the production process of the circuit board and have a good environmental protection effect.

[0062] The above are all the preferred embodiments of the present application. The protection scope of the present application is not limited by this. Therefore, all equivalent changes made according to the structure, shape, and principle of the present application should be covered within the protection scope of the present application.

Claims

1. An ion exchange reaction device for recovering copper from micro-etching solution of circuit boards, characterized in that: The invention comprises a resin column (1) for absorbing copper ions in a micro-etching solution, wherein the resin column (1) is provided with an electrolysis mechanism (2) for removing copper ions in the resin column (1) and restoring the adsorption capacity of the resin column (1), wherein the electrolysis mechanism (2) comprises: An electrolytic cell (3), the electrolytic cell (3) being arranged at the bottom of the resin column (1), the electrolytic cell (3) containing an electrolyte that is convenient for releasing copper ions from the resin column (1); A circulation component (4), the circulation component (4) being arranged on the electrolytic cell (3) and used to discharge the electrolyte into the resin column (1) and to discharge the released copper ions back into the electrolytic cell (3) along with the electrolyte; A collecting component (5) is arranged in the electrolytic cell (3) and replaces copper ions in the electrolyte with copper by an electrochemical method and collects the copper.

2. The ion exchange reaction device for recovering copper from circuit board micro-etching solution according to claim 1, characterized in that: The circulation component (4) comprises: A feed pipe (41), wherein the feed pipe (41) is arranged in the electrolytic cell (3) and the other end of the feed pipe is arranged on the top of the resin column (1); a driving pump (42), the driving pump (42) being arranged on the electrolytic cell (3) and being in communication with the feed pipe (41), the driving pump (42) being used to discharge the electrolyte in the electrolytic cell (3) into the resin column (1) through the feed pipe (41); a discharge pipe (43), the discharge pipe (43) being arranged on an end of the resin column (1) away from the feed pipe (41), the discharge pipe (43) being used to discharge the electrolyte passing through the resin column (1) into the electrolytic cell (3); A first control valve (44), the first control valve (44) is arranged on the discharge pipe (43) and is used to control the opening and closing of the discharge pipe (43).

3. The ion exchange reaction device for recovering copper from circuit board micro-etching solution according to claim 2, characterized in that: The collecting component (5) comprises: A power supply (51), the power supply (51) being arranged on the electrolytic cell (3) and used for providing power; A positive electrode block (52), the positive electrode block (52) being arranged in the electrolytic cell (3) and electrically connected to the positive electrode of the power supply unit (51); an adsorption block (53), the adsorption block (53) being arranged in the electrolytic cell (3) and electrically connected to the negative electrode of the power supply unit (51), the adsorption block (53) being used to adsorb and collect the displaced copper; A diaphragm plate (54) is arranged in the electrolytic cell (3) and divides the electrolytic cell (3); the diaphragm plate (54) allows ions to pass through.

4. The ion exchange reaction device for recovering copper from circuit board micro-etching solution according to claim 3, characterized in that: The adsorption block (53) is a pure copper block, and the top of the adsorption block (53) is detachably arranged in the electrolytic cell (3) via a locking bolt.

5. The ion exchange reaction device for recovering copper from circuit board micro-etching solution according to claim 2, characterized in that: The resin column (1) comprises: A glass cylinder (11), wherein the glass cylinder (11) is tightly filled with a resin material for absorbing copper ions in a micro-etching solution; A sealing cover (12), the sealing cover (12) being arranged on the glass cylinder (11) and used to seal the opening of the glass cylinder (11), and the feed pipe (41) being arranged on the sealing cover (12); An inlet pipe (13), the inlet pipe (13) being arranged on the sealing cover (12) and used for discharging the micro-etching liquid into the glass cylinder (11); a discharge pipe (14), the discharge pipe (14) being arranged on an end of the glass cylinder (11) away from the sealing cover (12), the discharge pipe (14) being used to discharge the micro-etching liquid after copper ions are adsorbed by the resin material; A second control valve (15), wherein the second control valve (15) is arranged on the discharge pipe (14) and is used to control the opening and closing of the discharge pipe (14).

6. The ion exchange reaction device for recovering copper from circuit board micro-etching solution according to claim 5, characterized in that: The glass cylinder (11) is provided with a control panel, and the control panel controls the opening and closing of the first control valve (44) and the second control valve (15) according to the opening states of the inlet pipe (13) and the feed pipe (41).

7. The ion exchange reaction device for recovering copper from circuit board micro-etching solution according to claim 5, characterized in that: A filter cartridge (16) for preventing the resin material from escaping is clamped on the glass cartridge (11), and the filter cartridge (16) is used to filter the micro-etching solution or the electrolyte.

8. The ion exchange reaction device for recovering copper from circuit board micro-etching solution according to claim 5, characterized in that: A one-way valve (411) is provided at one end of the feed pipe (41) close to the sealing cover (12), and the one-way valve (411) is used to prevent the micro-etching liquid in the resin column (1) from flowing into the feed pipe (41).

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