METHOD FOR ELECTROLYSIS-ASSISTED OXIDATIVE REGENERATION OF ALKALINE COPPER-AMMONIA CHLORIDE ETCHING WORKING SOLUTION, AND APPARATUS USING SAME

Abstract

Provided are a method for electrolysis-assisted oxidative regeneration of an alkaline copper-ammonia chloride etching working solution, and an apparatus using the same. The method includes the following steps: (1) selecting an electrolytic cell provided with an electrolytic cell separator; (2) with the alkaline copper-ammonia chloride etching working solution as an anode electrolyte, conducting electrolysis in the electrolytic cell, where a reaction of oxidatively regenerating a copper-etching agent occurs in the anode cell zone; and during the electrolysis, an etching working solution circularly flows between the etching machine and the anode cell zone of the electrolytic cell; and (3) during the electrolysis, controlling an oxidation-reduction potential (ORP) potential value of the anode electrolyte at 300 mV or less, and feeding an etching replenisher into the alkaline copper-ammonia chloride etching working solution to participate in the reaction of oxidatively regenerating the copper-etching agent.

Claims

1. A method for electrolysis-assisted oxidative regeneration of an alkaline copper-ammonia chloride etching working solution, wherein the alkaline copper-ammonia chloride etching working solution is used for etching on an etching machine, and the method comprises the following steps: (1) selecting an electrolytic cell provided with an electrolytic cell separator, wherein the electrolytic cell is divided by the electrolytic cell separator into an anode cell zone and a cathode cell zone; an anode is provided in the anode cell zone and is connected to a positive electrode of an electrolytic power supply; and a cathode is provided in the cathode cell zone and is connected to a negative electrode of the electrolytic power supply; (2) with the alkaline copper-ammonia chloride etching working solution as an anode electrolyte, conducting electrolysis in the electrolytic cell, wherein a reaction of oxidatively regenerating a copper-etching agent occurs in the anode cell zone; and during the electrolysis, the alkaline copper-ammonia chloride etching working solution circularly flows between the etching machine and the anode cell zone of the electrolytic cell; and (3) during the electrolysis, controlling an oxidation-reduction potential (ORP) value of the anode electrolyte at 300 mV or less, and feeding an etching replenisher into the alkaline copper-ammonia chloride etching working solution to participate in the reaction of oxidatively regenerating the copper-etching agent, such that a pH value and/or a copper ion concentration of the alkaline copper-ammonia chloride etching working solution on the etching machine are/is controlled within a set process range.

2. The method for electrolysis-assisted oxidative regeneration of an alkaline copper-ammonia chloride etching working solution according to claim 1, wherein the electrolytic cell separator is a material capable of effectively blocking entrance of copper ions and ammonium ions from the anode cell zone into the cathode cell zone.

3. The method for electrolysis-assisted oxidative regeneration of an alkaline copper-ammonia chloride etching working solution according to claim 2, wherein the electrolytic cell separator is at least one selected from the group consisting of a reverse osmosis membrane, a bipolar membrane, a proton exchange membrane, and an ion selectivity-free membrane, and a cathode electrolyte is an ammonia and/or ammonium-containing alkaline solution.

4. The method for electrolysis-assisted oxidative regeneration of an alkaline copper-ammonia chloride etching working solution according to claim 3, wherein the electrolytic cell separator is the reverse osmosis membrane and/or the bipolar membrane and/or the ion selectivity-free membrane, and the cathode electrolyte of the electrolytic cell is a spent etching solution from the same etching solution system as the anode electrolyte.

5. The method for electrolysis-assisted oxidative regeneration of an alkaline copper-ammonia chloride etching working solution according to claim 2, wherein the electrolytic cell separator is an anion-exchange membrane, and the cathode electrolyte is ammonia water.

6. The method for electrolysis-assisted oxidative regeneration of an alkaline copper-ammonia chloride etching working solution according to claim 1, wherein in order to effectively avoid excessive consumption of reductive substances other than a monovalent copper-ammonia complex in the alkaline copper-ammonia chloride etching working solution, at least one of the following measures is adopted: measure 1: during the electrolysis, reducing the ORP value of the anode electrolyte to control the ORP value of the anode electrolyte at less than or equal to 280 mV; measure 2: during the electrolysis, increasing an effective electrolytic area of the anode in the electrolytic cell; measure 3: increasing a solution circulation flow rate between the anode cell zone of the electrolytic cell and the etching machine to allow solution exchange and mixing; and measure 4: providing a solution mixing-exchange tank on a connecting pipeline between the anode cell zone of the electrolytic cell and the etching machine, and connecting the solution mixing-exchange tank to the anode cell zone of the electrolytic cell and the etching machine; and increasing a solution circulation flow rate between the anode cell zone of the electrolytic cell and the solution mixing-exchange tank or increasing a solution circulation flow rate between the anode cell zone of the electrolytic cell and the etching machine and the solution circulation flow rate between the anode cell zone of the electrolytic cell and the solution mixing-exchange tank to allow solution exchange and mixing.

7. The method for electrolysis-assisted oxidative regeneration of an alkaline copper-ammonia chloride etching working solution according to claim 6, wherein at least two parameters selected from the group consisting of an ORP value, the pH value, and a specific gravity value of the alkaline copper-ammonia chloride etching working solution on the etching machine are detected and monitored, and operations of the electrolytic cell and a feeding device for the etching replenisher are controlled based on detected parameter results.

8. The method for electrolysis-assisted oxidative regeneration of an alkaline copper-ammonia chloride etching working solution according to claim 7, wherein the ORP value of the anode electrolyte and/or an ORP value of a solution in the solution mixing-exchange tank are/is detected and monitored, and an output working current or start/stop of the electrolytic power supply of the electrolytic cell is controlled according to a preset ORP value for the anode electrolyte and/or a preset ORP value for the solution in the solution mixing-exchange tank; and at least one selected from the group consisting of an ORP value, a pH value, and a specific gravity value of the cathode electrolyte is detected and monitored to control an electrochemical reaction in the cathode cell zone.

9. The method for electrolysis-assisted oxidative regeneration of an alkaline copper-ammonia chloride etching working solution according to claim 8, wherein a measure is taken to make an exhaust air volume in a spray-oxygen absorption-exhausting system on the etching machine adjustable, which reduces a fresh air supply volume while enabling the reaction of oxidatively regenerating a copper-etching agent and optimizes overall production conditions for a spray-oxygen absorption reaction based on a fresh air supply and discharge of an ammonia-polluted tail gas.

10. An apparatus for electrolysis-assisted oxidative regeneration of an alkaline copper-ammonia chloride etching working solution using the method according to claim 1, comprising an etching machine, an etching replenisher tank, and an electrolytic cell, wherein an electrolytic cell separator is provided in the electrolytic cell, and the electrolytic cell is divided by the electrolytic cell separator into an anode cell zone and a cathode cell zone; an anode is provided in the anode cell zone and is connected to a positive electrode of an electrolytic power supply; a cathode is provided in the cathode cell zone and is connected to a negative electrode of the electrolytic power supply; the anode cell zone of the electrolytic cell is connected to the etching machine through a pipeline to allow a liquid circulation flow between the anode cell zone of the electrolytic cell and the etching machine, such that the alkaline copper-ammonia chloride etching working solution undergoes an oxidative regeneration reaction in the electrolytic cell during the liquid circulation flow; and the etching replenisher tank is connected to the etching machine and/or the anode cell zone of the electrolytic cell, and is configured to store an etching replenisher.

11. The apparatus according to claim 10, wherein the etching machine is connected to the anode cell zone of the electrolytic cell through at least two pipelines, and at least one of the at least two pipelines is provided with a pump to achieve a circulation flow of an etching working solution.

12. The apparatus according to claim 11, wherein the electrolytic cell separator is at least one selected from the group consisting of a bipolar membrane, a reverse osmosis membrane, an anion-exchange membrane, a proton exchange membrane, and an ion selectivity-free membrane.

13. The apparatus according to claim 12, wherein at least one pipeline between the anode cell zone of the electrolytic cell and the etching machine is provided with a solution mixing-exchange tank; the solution mixing-exchange tank is connected to each of the etching machine and the anode cell zone of the electrolytic cell through a pipeline, and is connected to at least one of the etching machine and the anode cell zone of the electrolytic cell through at least two pipelines to form a liquid flow circulation, such that solutions in the solution mixing-exchange tank, the etching machine, and the anode cell zone of the electrolytic cell undergo mixing and exchange; and the etching replenisher tank is connected to at least one of the etching machine, the anode cell zone of the electrolytic cell, and the solution mixing-exchange tank.

14. The apparatus according to claim 13, wherein a temporary storage tank configured to store a material or serve as a chemical reaction tank is provided; and the temporary storage tank is connected to at least one of the etching machine, the electrolytic cell, and the solution mixing-exchange tank through a pipeline, or is arranged on a connecting pipeline between any two of the etching machine, the electrolytic cell, and the solution mixing-exchange tank.

15. The apparatus according to claim 14, wherein a sensor is provided in at least one of the etching machine, the electrolytic cell, the solution mixing-exchange tank, and the temporary storage tank, and the sensor is one or more selected from the group consisting of an ORP meter, a pH meter, a liquid level meter, a thermometer, and a gravimeter; an automatic detection/feeding controller is provided; and a control signal output terminal of the automatic detection/feeding controller is connected to a control signal input terminal of at least one pump and/or a feeding device and/or the electrolytic power supply in the apparatus, and the automatic detection/feeding controller is configured to control the apparatus according to a preset time program and/or a value measured by the sensor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0074] FIG. 1 is a schematic diagram of an apparatus and process flow for electrolysis-assisted oxidative regeneration of an alkaline copper-ammonia chloride etching working solution in Example 1 of the present disclosure;

[0075] FIG. 2 is a schematic diagram of an apparatus and process flow for electrolysis-assisted oxidative regeneration of an alkaline copper-ammonia chloride etching working solution in Example 2 of the present disclosure;

[0076] FIG. 3 is a schematic diagram of an apparatus and process flow for electrolysis-assisted oxidative regeneration of an alkaline copper-ammonia chloride etching working solution in Example 3 of the present disclosure;

[0077] FIG. 4 is a schematic diagram of an apparatus and process flow for electrolysis-assisted oxidative regeneration of an alkaline copper-ammonia chloride etching working solution in Example 4 of the present disclosure; and

[0078] FIG. 5 is a schematic diagram of an apparatus and process flow for electrolysis-assisted oxidative regeneration of an alkaline copper-ammonia chloride etching working solution in Example 5 of the present disclosure.

[0079] Reference numerals: 1etching machine, 2electrolytic cell, 3electrolytic cell separator, 4electrolytic anode, 5electrolytic cathode, 6electrolytic power supply, 7sealing cell cover with a feeding and exhaust port for the electrolytic cell, 8etching replenisher tank, 9sensor, 10automatic detection/feeding controller, 11heat exchanger, 12solid-liquid separator, 13temporary storage tank, 14liquid flow buffer tank, 15liquid flow circulation stirrer, 16impeller stirrer, 17solution mixing-exchange tank, 18hydrogen high-altitude discharge pipe, 19valve, 20pump, 21etching replenisher, 22spent etching solution, 23etching working solution, 24solution that has undergone a reduction treatment at the electrolytic cathode, 25cathode electrolyte, 26printed circuit board to be etched, 27tail gas treatment device, 28metallic copper, 29gas flow-regulating valve, 30variable-frequency fan, 31acidic reaction solution for a tail gas treatment, and 32nozzle.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0080] The present disclosure is further described below through specific embodiments.

[0081] The electrolytic cell, the temporary storage tank, the liquid flow buffer tank, the liquid flow circulation stirrer, the etching replenisher tank, the hydrogen high-altitude discharge pipe, and the solution mixing-exchange tank adopted in the following embodiments all are products of Yegao Environmental Protection Equipment Manufacturing Co., Ltd., Foshan City, Guangdong Province, China. YH-510A is an alkaline etching reducing additive product marketed by Yegao Chemical Co., Ltd. The etching machine, the heat exchanger, the electrolytic power supply, the sensor, the automatic detection/feeding controller, the valve, the pump, and the chemical raw material all are commercially-available products. Other products with similar properties to the products listed in the present disclosure may also be adopted by those skilled in the art according to conventional selection, which all can achieve the objectives of the present disclosure.

Example 1

[0082] FIG. 1 shows an apparatus and process flow for electrolysis-assisted oxidative regeneration of an alkaline copper-ammonia chloride etching working solution in this example. The apparatus includes an etching machine 1, an electrolytic cell 2, an electrolytic cell separator 3, an electrolytic power supply 6, an etching replenisher tank 8, sealing cell covers 7-1 and 7-2 each with a feeding and exhaust port for the electrolytic cell, sensors 9-1, 9-2, and 9-3, a hydrogen high-altitude discharge pipe 18, an etching replenisher 21, an etching working solution 23, a cathode electrolyte 25, a printed circuit board to be etched 26, a tail gas treatment device 27, a gas flow-regulating valve 29, a valve, and a pump.

[0083] The electrolytic cell 2 is divided by the electrolytic cell separator 3 into an anode cell zone and a cathode cell zone. The anode cell zone is connected to the etching machine 1 through two pipelines for a liquid flow circulation. The sealing cell covers 7-1 and 7-2 each with a feeding and exhaust port for the electrolytic cell are arranged for the anode cell zone and the cathode cell zone, respectively. The etching replenisher tank 8 is connected to the etching machine 1 through a pipeline.

[0084] The electrolytic cell separator 3 is an anion-exchange membrane. An electrolytic anode is a titanium-based coated electrode, and an electrolytic cathode is a stainless steel. The cathode electrolyte 25 is 12% ammonia water. The etching working solution is a mixed solution of main components of copper-ammonia chloride, ammonia water, and ammonium chloride. Specific process parameters are listed in Table 1.

[0085] In this example, a spray-oxygen absorption-exhausting system is provided, which is a treatment apparatus combining a spray device and the tail gas treatment device 27. The spray device includes pipelines arranged on the etching machine, a pump 20-2, and a nozzle 32, and is configured to direct the etching working solution to be above the spray device for spray atomization. The tail gas treatment device 27 is configured to receive waste gases from the etching machine 1, the electrolytic cell 2, and the etching replenisher tank 8 through gas pipelines. The gas flow-regulating valve 29 is arranged on a gas pipeline of the etching machine 1.

[0086] The sensor 9-1 is an ORP meter, the sensor 9-2 is a gravimeter, and the sensor 9-3 is an ORP meter.

[0087] In this example, operation steps for the electrolysis-assisted oxidative regeneration of an alkaline copper-ammonia chloride etching working solution in this example were as follows:

[0088] 1. The etching working solution 23 was fed into the etching machine 1 and the anode cell zone of the electrolytic cell 2, with the etching working solution circularly flowing between the etching machine and the anode cell zone of the electrolytic cell. 12% ammonia water was fed into the cathode cell zone of the electrolytic cell 2. The gas flow-regulating valve 29 was maintained at the original fully-open state.

[0089] 2. The spray-oxygen absorption-exhausting system of the etching machine was started. The printed circuit board to be etched 26 was fed into the etching machine 1 for etching. The feeding of the etching replenisher 21 was controlled according to a value detected by the sensor 9-2 as a gravimeter to ensure that the etching working solution met the set process parameters. If a value detected by the sensor 9-1 as an ORP meter was 150 my or less, the electrolytic power supply 6 was turned on for electrolysis to allow the oxidative regeneration for the etching working solution. The turn-off of the electrolytic power supply 6 was controlled based on a value detected by the sensor 9-3 as an ORP meter and a set safety threshold of 150 mv. During the electrolysis, a monovalent copper-ammonia complex in an anode electrolyte was oxidized into a copper-etching agent Cu(NH.sub.3).sub.4Cl.sub.2, and hydrogen was electrodeposited at the cathode 5.

[0090] 3. During an etching process, with an exhaust flux in the spray-oxygen absorption-exhausting system undiminished, electrolysis-assisted oxidation was adopted in combination to achieve the oxidative regeneration of the copper-etching agent, thereby enhancing an etching rate.

[0091] 4. A polluted waste gas from each cell/tank in the apparatus was directed to the tail gas treatment device 27 for an environmental treatment.

[0092] 5. Hydrogen from the cathode cell zone was directed to the hydrogen high-altitude discharge pipe for safe discharge.

[0093] According to the etching working solutions shown in Table 1, an etching working solution was subjected to oxidative regeneration with the traditional spray-oxygen absorption system. A measured etching rate was recorded in Table 1. Then, the electrolysis apparatus was started, and with the oxidative regeneration scheme of traditional spray-oxygen absorption system+electrolytic oxidative regeneration apparatus in the present disclosure, the etching working solution was subjected to oxidative regeneration according to the above steps. A measured etching rate was recorded in Table 1.

[0094] The etching rates of the above two processes were compared. The addition of the electrolysis-assisted oxidation apparatus without diminishing an exhaust flux in the traditional spray-oxygen absorption-exhausting system improved the etching production efficiency by 14%.

[0095] Test results showed that, after long-term etching and electrolysis-assisted oxidative regeneration, contents of ammonia water and ammonium ions in the etching working solution did not significantly change.

[0096] Specific process parameters were listed in Table 1.

Example 2

[0097] FIG. 2 shows an apparatus and process flow for electrolysis-assisted oxidative regeneration of an alkaline copper-ammonia chloride etching working solution in this example.

[0098] The apparatus includes an etching machine 1, an electrolytic cell 2, an electrolytic cell separator 3, an electrolytic power supply 6, an etching replenisher tank 8, sealing cell covers 7-1 and 7-2 each with a feeding and exhaust port for the electrolytic cell, sensors 9-1, 9-2, and 9-3, a liquid flow buffer tank 14, an etching replenisher 21, an etching working solution 23, a cathode electrolyte 25, a printed circuit board to be etched 26, a tail gas treatment device 27, a gas flow-regulating valve 29, a valve, and a pump.

[0099] The electrolytic cell 2 is divided by the electrolytic cell separator 3 into an anode cell zone and a cathode cell zone. The sealing cell covers 7-1 and 7-2 each with a feeding and exhaust port for the electrolytic cell are arranged for the anode cell zone and the cathode cell zone, respectively. The anode cell zone is connected to the etching machine 1 through the liquid flow buffer tank 14, and the etching machine 1 is connected to the anode cell zone through another pipeline, thereby achieving a liquid flow circulation between the anode cell zone and the etching machine. The etching replenisher tank 8 is connected to the etching machine 1 through a pipeline.

[0100] The electrolytic cell separator 3 is a bipolar membrane. An electrolytic anode is a platinum electrode, and an electrolytic cathode is a stainless steel. The cathode electrolyte 25 is a copper-ammonia complex solution. The etching working solution is a mixed solution of copper-ammonia chloride, ammonium chloride, ammonium carbonate, and YH-510A. Specific process parameters are listed in Table 1.

[0101] In this example, a spray-oxygen absorption-exhausting system is provided, which is a treatment apparatus combining a spray device and the tail gas treatment device 27. The spray device includes pipelines arranged on the etching machine, a pump 20-2, and a nozzle 32, and is configured to direct the etching working solution to be above the spray device for spray atomization. The tail gas treatment device 27 is configured to receive waste gases from the etching machine 1, the electrolytic cell 2, and the etching replenisher tank 8 through gas pipelines. The gas flow-regulating valve 29 is arranged on a gas pipeline of the etching machine 1.

[0102] The sensor 9-1 is an ORP meter, the sensor 9-2 is a gravimeter, and the sensor 9-3 is an ORP meter.

[0103] In this example, operation steps for the electrolysis-assisted oxidative regeneration of an alkaline copper-ammonia chloride etching working solution in this example were as follows:

[0104] 1. The etching working solution 23 was fed into the etching machine 1 and the anode cell zone of the electrolytic cell 2, with the etching working solution circularly flowing between the etching machine and the anode cell zone of the electrolytic cell. The copper-ammonia complex solution 25 was fed into the cathode cell zone of the electrolytic cell 2. The gas flow-regulating valve 29 was maintained at the original fully-open state.

[0105] 2. The spray-oxygen absorption-exhausting system of the etching machine was started. The printed circuit board to be etched 26 was fed into the etching machine 1 for etching. The feeding of the etching replenisher 21 was controlled according to a value detected by the sensor 9-2 as a gravimeter to ensure that the etching working solution met the set process parameters. If a value detected by the sensor 9-1 as an ORP meter was 280 my or less, the electrolytic power supply 6 was turned on for electrolysis to allow the oxidative regeneration for the etching working solution. The turn-off of the electrolytic power supply 6 was controlled based on a value detected by the sensor 9-3 as an ORP meter and a set safety threshold of 280 mv. During the electrolysis, a monovalent copper-ammonia complex in an anode electrolyte was oxidized into a copper-etching agent Cu(NH.sub.3).sub.4Cl.sub.2, and metallic copper 28 was electrodeposited at the cathode 5.

[0106] 3. During an etching process, with an exhaust flux in the spray-oxygen absorption-exhausting system undiminished, electrolysis-assisted oxidation was adopted in combination to achieve the oxidative regeneration of the copper-etching agent, thereby enhancing an etching rate.

[0107] 4. A polluted waste gas from each cell/tank in the apparatus was directed to the tail gas treatment device 27 for an environmental treatment.

[0108] The copper-ammonia complex solution in this example was a tetraamminecopper (II) hydroxide solution. According to the etching working solutions shown in Table 1, an etching working solution was subjected to oxidative regeneration with the traditional spray-oxygen absorption system. A measured etching rate was recorded in Table 1. Then, the electrolysis apparatus was started, and with the oxidative regeneration scheme of traditional spray-oxygen absorption system+electrolytic oxidative regeneration apparatus in the present disclosure, the etching working solution was subjected to oxidative regeneration according to the above steps. A measured etching rate was recorded in Table 1.

[0109] The etching rates of the above two processes were compared. The addition of the electrolysis-assisted oxidation apparatus without diminishing an exhaust flux in the spray-oxygen absorption-exhausting system improved the etching production efficiency by 14%. Test results showed that, after long-term etching and electrolysis-assisted oxidative regeneration, contents of ammonium ions, ammonium carbonate, and YH-510A in the etching working solution did not significantly change.

[0110] Specific process parameters were listed in Table 1.

Example 3

[0111] FIG. 3 shows an apparatus and process flow for electrolysis-assisted oxidative regeneration of an alkaline copper-ammonia chloride etching working solution in this example. The apparatus includes an etching machine 1, an electrolytic cell 2, an electrolytic cell separator 3, an electrolytic power supply 6, an etching replenisher tank 8, sensors 9, a solid-liquid separator 12, a temporary storage tank 13, a liquid flow buffer tank 14, a hydrogen high-altitude discharge pipe 18, an etching replenisher 21, an etching working solution 23, a cathode electrolyte 25, a printed circuit board to be etched 26, a tail gas treatment device 27, a variable-frequency fan 30, and a plurality of valves and pumps.

[0112] The electrolytic cell 2 is divided by the electrolytic cell separator 3 into an anode cell zone and a cathode cell zone. The sealing cell covers 7-1 and 7-2 each with a feeding and exhaust port for the electrolytic cell are arranged for the anode cell zone and the cathode cell zone, respectively. The anode cell zone is connected to the etching machine 1 and the temporary storage tank 13 through the liquid flow buffer tank 14, and the etching machine 1 is connected to the anode cell zone through the solid-liquid separator 12, thereby achieving a liquid flow circulation between the anode cell zone and the etching machine 1. The etching replenisher tank 8 is connected to the etching machine 1 through a pipeline.

[0113] The electrolytic cell separator 3 is a reverse osmosis membrane, the electrolytic anode 4 is a graphite electrode, and the electrolytic cathode 5 is graphite. The cathode electrolyte 25 is a 10% ammonium carbonate solution. The etching working solution 23 is a mixed solution of copper-ammonia chloride, ammonia water, ammonium chloride, ammonium bicarbonate, and YH-510A. Specific process parameters are listed in Table 1.

[0114] A sensor 9-1 is a liquid level meter, a sensor 9-2 is a pH meter, a sensor 9-3 is a gravimeter, a sensor 9-4 is an ORP meter, and a sensor 9-5 is an ORP meter.

[0115] In this example, a spray-oxygen absorption-exhausting system is provided, which is a treatment apparatus combining a spray device and the tail gas treatment device 27. The spray device includes pipelines arranged on the etching machine, a pump 20-2, and a nozzle 32. The tail gas treatment device 27 is configured to receive waste gases from the etching machine 1, the electrolytic cell 2, the etching replenisher tank 8, and the temporary storage tank 13 through gas pipelines.

[0116] In this example, operation steps for the electrolysis-assisted oxidative regeneration of an alkaline copper-ammonia chloride etching working solution in this example were as follows:

[0117] 1. The etching working solution 23 was fed into the etching machine 1 and the anode cell zone of the electrolytic cell, and the cathode electrolyte 25 was fed into the cathode cell zone of the electrolytic cell. A rotational speed of the variable-frequency fan 30 arranged at the tail gas treatment device 27 was reduced from the original 1,400 rpm to 1,200 rpm. A spray pump 20-2 arranged on the etching machine 1 was turned on to make the etching working solution undergo an oxidation reaction with oxygen in air during a spray atomization process. Pumps 20-3 and 20-4 were turned on to make the etching working solution circularly flow between the etching machine 1 and the anode cell zone of the electrolytic cell 2. During the circulation flow, solid impurities in the etching working solution were removed through the solid-liquid separator 12.

[0118] 2. The printed circuit board to be etched 26 was fed into the etching machine 1 for etching, during which a specific gravity value of the etching working solution continuously increased and an ORP value of the etching working solution decreased. A pump 20-1 was controlled to feed the etching replenisher 21 into an etching machine based on a value detected by the sensor 9-3 as a gravimeter. An operation of the electrolytic cell 2 was controlled based on a value detected by the sensor 9-4 as an ORP meter. The turn-off of the electrolytic power supply 6 was controlled based on a value detected by the sensor 9-5 as an ORP meter and a set safety threshold of 80 mv. The turn-on of a pump 20-5 was controlled based on a value detected by the sensor 9-1 as a liquid level meter to discharge a solution as a spent etching solution. When the electrolytic cell 2 was started to enable electrolysis-assisted oxidation, a monovalent copper-ammonia complex in an anode electrolyte underwent an electrochemical oxidation reaction at the anode to regenerate a copper-etching agent, and hydrogen was electrodeposited at the cathode.

[0119] 3. During an etching process, the rotational speed of the variable-frequency fan 30 was reduced to decrease the emission of an ammonia-containing waste gas, and a process for electrolysis-assisted oxidative regeneration of a copper-etching agent was adopted in combination, thereby maintaining the original etching rate.

[0120] 4. Hydrogen electrodeposited at the cathode was directed to a hydrogen high-altitude discharge pipe and discharged.

[0121] 5. A polluted waste gas from each cell/tank in the apparatus was directed to the tail gas treatment device 27 for an environmental treatment.

[0122] According to the etching working solutions shown in Table 1, an etching working solution was subjected to oxidative regeneration with the traditional spray-oxygen absorption system, in which case the rotational speed of the variable-frequency fan 30 was 1,400 rpm. A measured etching rate was recorded in Table 1. Then, the electrolysis apparatus was started, and with the oxidative regeneration scheme of traditional spray-oxygen absorption system+electrolytic oxidative regeneration apparatus in the present disclosure, the etching working solution was subjected to oxidative regeneration according to the above steps. A measured etching rate was recorded in Table 1. According to the comparison of etching rates in Example 3, when the efficiency of the traditional spray-oxygen absorption system to regenerate the copper-etching agent was directly lowered after the reduction in the rotational speed of the variable-frequency fan 30 (the reduction in a flow rate of fresh air), the addition of the electrolysis-assisted oxidative regeneration apparatus to facilitate the oxidative regeneration of the copper-etching agent can meet the original etching production requirements. According to test results, in the present disclosure, after the electrolysis-assisted oxidation was adopted in combination with the adjustment of the spray-oxygen absorption system, an ammonia gas loss caused by extraction was reduced by 50%. After long-term etching and electrolysis-assisted oxidative regeneration, contents of ammonia water, ammonium ions, ammonium bicarbonate, and YH-510A in the etching working solution did not significantly change.

[0123] Specific process parameters were listed in Table 1.

Example 4

[0124] FIG. 4 shows an apparatus and process flow for electrolysis-assisted oxidative regeneration of an alkaline copper-ammonia chloride etching working solution in this example.

[0125] The apparatus includes an etching machine 1, an electrolytic cell 2, an electrolytic cell separator 3, an electrolytic anode 4, an electrolytic cathode 5, an electrolytic power supply 6, sealing cell covers 7 with a feeding and exhaust port for the electrolytic cell, an etching replenisher tank 8, seven sensors 9, an automatic detection/feeding controller 10, a heat exchanger 11, a solid-liquid separator 12, two temporary storage tanks 13, three liquid flow buffer tanks 14, a liquid flow circulation stirrer 15, a solution mixing-exchange tank 17, an etching replenisher 21, a spent etching solution 22, an etching working solution 23, a solution 24 that has undergone a reduction treatment at the electrolytic cathode, a cathode electrolyte 25, a printed circuit board to be etched 26, a tail gas treatment device 27, a gas flow-regulating valve 29, a variable-frequency fan 30, and a plurality of valves and pumps.

[0126] The electrolytic cell 2 is divided by the electrolytic cell separator 3 into an anode cell zone and a cathode cell zone. The sealing cell covers each with a feeding and exhaust port for the electrolytic cell are arranged for the anode cell zone and the cathode cell zone, respectively. The anode cell zone is connected to the solution mixing-exchange tank 17 through two pipelines to allow a liquid flow circulation. The cathode cell zone is connected to a temporary storage tank 13-2 through a liquid flow buffer tank 14-3. The etching machine 1 is connected to the solution mixing-exchange tank 17 through two pipelines to allow a liquid flow circulation. The etching machine 1 is additionally connected to the cathode cell zone through a liquid flow buffer tank 14-1 and a temporary storage tank 13-1. The etching replenisher tank 8 is connected to the etching machine 1 through a pipeline.

[0127] The electrolytic cell separator 3 is a bipolar membrane. The electrolytic anode 4 is a titanium-based coated insoluble anode, and the electrolytic cathode 5 is a titanium metal block. The cathode electrolyte 25 is the spent etching solution 22 produced after an etching operation in this example.

[0128] The etching working solution is a mixed solution of copper-ammonia chloride, ammonia water, ammonium chloride, and YH-510A. Specific process parameters are listed in Table 1.

[0129] A sensor 9-1 is a thermometer, a sensor 9-2 is a gravimeter, a sensor 9-3 is an ORP meter, a sensor 9-4 is a thermometer, and sensors 9-5, 9-6, and 9-7 all are ORP meters.

[0130] In this example, a spray-oxygen absorption-exhausting system is provided, which is a treatment apparatus combining a spray device and the tail gas treatment device 27. The spray device includes pipelines arranged on the etching machine, a pump 20-4, and a nozzle 32. The tail gas treatment device 27 is configured to receive waste gases from the etching machine 1, the electrolytic cell 2, the etching replenisher tank 8, the solution mixing-exchange tank 17, and the temporary storage tanks 13-1 and 13-2 through gas pipelines. The gas flow-regulating valve 29 is arranged on a gas pipeline of the etching machine 1.

[0131] In this example, a detection signal input terminal of the automatic detection/feeding controller 10 is connected to a detection signal output terminal of each sensor, and a control signal output terminal of the automatic detection/feeding controller 10 is connected to control signal input terminals of each pump, the electrolytic power supply 6, and the heat exchanger 11.

[0132] In this example, operation steps for the electrolysis-assisted oxidative regeneration of an alkaline copper-ammonia chloride etching working solution in this example were as follows:

[0133] 1. A power supply for the entire apparatus was turned on. Under the control of the automatic detection/feeding controller 10, the on-site detection was conducted through various sensors. The detected data was transmitted to the automatic detection/feeding controller 10 for processing. After the processing, a command was issued according to a program to make each device run.

[0134] 2. An opening of the gas flow-regulating valve 29 was set to 80% of the original fully-open opening. The etching working solution 23 was fed into the etching machine 1, the anode cell zone of the electrolytic cell, and the solution mixing-exchange tank 17. The spent etching solution 22 was fed into the cathode cell zone. The pump 20-4 on the etching machine was started to make the etching working solution undergo an oxidation reaction with oxygen in air through spray atomization. Pumps 20-5 and 20-6 were started to make the etching working solution circularly flow between the etching machine 1 and the solution mixing-exchange tank 17. Pumps 20-7 and 20-8 were started to make a solution in the solution mixing-exchange tank 17 circularly flow between the solution mixing-exchange tank and the anode cell zone of the electrolytic cell.

[0135] 3. The printed circuit board to be etched 26 was fed into the etching machine for etching. A pump 20-1 was controlled to feed the etching replenisher 21 based on data detected by the sensor 9-2 as a gravimeter. A concentration of a copper-etching agent in the etching working solution was monitored by the sensor 9-3 as an ORP meter, and an etching rate was adjusted accordingly. The sensor 9-5 as an ORP meter was started to monitor ORP of the etching working solution, and a working current or turn-off of the electrolytic power supply 6 was controlled accordingly. For the sensor 9-6 as an ORP meter, a safety threshold of 50 my was set as a safety interlock for controlling the turn-off of the electrolytic power supply 6.

[0136] After the electrolytic cell 2 was started to allow electrolysis-assisted oxidation, a monovalent copper-ammonia chloride complex in the anode electrolyte was oxidatively regenerated into the copper-etching agent Cu(NH.sub.3).sub.4Cl.sub.2, and an ORP value of the cathode electrolyte decreased due to an electrochemical reduction reaction. An ORP value of 15 mV was set for the sensor 9-7 as an ORP meter to control the feeding of the spent etching solution 22 into the cathode cell zone by the pump 20-2. If overflowing from the cathode cell zone, the cathode electrolyte was directed to a temporary storage tank 13-2 for temporary storage. A reduction reaction of divalent copper ions mainly occurred at the electrolytic cathode 5 without metallic copper deposited.

[0137] 4. A polluted tail gas from each cell/tank in the apparatus was directed to the tail gas treatment device 27 for an environmental treatment. A rotational speed of the variable-frequency fan 30 arranged at the tail gas treatment device 27 was reduced from the original 1,400 rpm to 1,300 rpm.

[0138] According to the etching working solutions shown in Table 1, an etching working solution was subjected to oxidative regeneration with the traditional spray-oxygen absorption system, in which case the gas flow-regulating valve 29 was fully open and the rotational speed of the variable-frequency fan 30 was 1,400 rpm. A measured etching rate was recorded in Table 1. Then, the electrolysis apparatus was started, and with the oxidative regeneration scheme of traditional spray-oxygen absorption system+electrolytic oxidative regeneration apparatus in the present disclosure, the etching working solution was subjected to oxidative regeneration according to the above steps. A measured etching rate was recorded in Table 1.

[0139] According to the comparison of etching rates of the two processes in Example 4, the measure of reducing an opening of the gas flow-regulating valve 29 to 80% of the original fully-open opening and reducing the rotational speed of the variable-frequency fan 30 (reducing a flow rate of fresh air) not only diminished the ammonia pollution, but also reduced the spray oxidation effect. On this basis, the present disclosure adopted an apparatus for electrolysis-assisted oxidative regeneration of the copper-etching agent, such that the original etching production efficiency could be maintained. Thus, the present disclosure achieved the energy conservation and emission reduction while guaranteeing the production efficiency. According to test results, in the present disclosure, after the electrolysis-assisted oxidation was adopted in combination with the adjustment of the spray-oxygen absorption system, an ammonia gas loss caused by extraction was reduced by 60%. After long-term etching and electrolysis-assisted oxidative regeneration, contents of ammonia water, ammonium ions, and YH-510A in the etching working solution did not significantly change.

[0140] Specific process parameters were listed in Table 1.

Example 5

[0141] FIG. 5 shows an apparatus and process flow for electrolysis-assisted oxidative regeneration of an alkaline copper-ammonia chloride etching working solution in this example. The apparatus includes an etching machine 1, an electrolytic cell 2, an electrolytic cell separator 3, an electrolytic anode 4, an electrolytic cathode 5, an electrolytic power supply 6, sealing cell covers 7 with a feeding and exhaust port for the electrolytic cell, an etching replenisher tank 8, nine sensors 9, an automatic detection/feeding controller 10, two heat exchangers 11, two temporary storage tanks 13, three liquid flow buffer tanks 14, a liquid flow circulation stirrer 15, a solution mixing-exchange tank 17, an etching replenisher 21, a spent etching solution 22, an etching working solution 23, a solution 24 that has undergone a reduction treatment at the electrolytic cathode, a cathode electrolyte 25, a printed circuit board to be etched 26, two tail gas treatment devices 27, electrodeposited metallic copper 28, a variable-frequency fan 30, and a plurality of valves and pumps.

[0142] The electrolytic cell 2 is divided by the electrolytic cell separator 3 into an anode cell zone and a cathode cell zone. The sealing cell covers for the electrolytic cell are arranged for the anode cell zone and the cathode cell zone, respectively. The anode cell zone is connected to the solution mixing-exchange tank 17 through two pipelines to allow a liquid flow circulation. The cathode cell zone is connected to a temporary storage tank 13-1 through a liquid flow buffer tank 14-3. The etching machine 1 is connected to the solution mixing-exchange tank 17 through two pipelines to allow a liquid flow circulation. The etching machine 1 is connected to a temporary storage tank 13-2. The etching replenisher tank 8 is connected to the etching machine 1 through a pipeline.

[0143] The electrolytic cell separator 3 is a reverse osmosis membrane, the electrolytic anode 4 is gold, and the electrolytic cathode 5 is a copper metal plate. The cathode electrolyte 25 is the spent etching solution 22 produced after an etching operation in this example.

[0144] The etching working solution is a mixed solution of copper-ammonia chloride, ammonia water, ammonium chloride, ammonium carbonate, ammonium bicarbonate, and YH-510A. Process parameters are listed in Table 1.

[0145] The electrolytic cathode 5 is a removable cathode copper plate. After a specified weight of a copper metal is electrodeposited, the cathode copper plate is taken out and recovered, and another cathode copper plate is placed in the cathode cell zone to continue an operation.

[0146] A sensor 9-1 is a thermometer, a sensor 9-2 is a pH meter, a sensor 9-3 is a gravimeter, a sensor 9-4 is an ORP meter, a sensor 9-5 is a thermometer, a sensor 9-6 is a liquid level meter, a sensor 9-7 is an ORP meter, a sensor 9-8 is an ORP meter, and a sensor 9-9 is a gravimeter.

[0147] The heat exchanger 11 is configured to control a temperature of the etching working solution to ensure the etching performance of the etching working solution.

[0148] In this example, a spray-oxygen absorption-exhausting system is provided, which is a treatment apparatus combining a spray device and a tail gas treatment device 27-1. The spray device includes pipelines arranged on the etching machine, a pump 20-2, and a nozzle 32. The tail gas treatment device 27-1 belongs to a specialized traditional spray-oxygen absorption-exhausting system, and is provided with the variable-frequency fan 30. The tail gas treatment device 27-1 is configured to receive a waste gas from the etching machine 1 through a gas pipeline. A tail gas treatment device 27-2 is configured to receive waste gases from the tail gas treatment device 27-1, the electrolytic cell 2, the etching replenisher tank 8, the solution mixing-exchange tank 17, and the temporary storage tanks 13-1 and 13-2 through gas pipelines. In this example, a detection signal input terminal of the automatic detection/feeding controller 10 is connected to a detection signal output terminal of each sensor, and a control signal output terminal of the automatic detection/feeding controller 10 is connected to control signal input terminals of each pump, the electrolytic power supply 6, and the heat exchanger 11.

[0149] In this example, operation steps for the electrolysis-assisted oxidative regeneration of an alkaline copper-ammonia chloride etching working solution in this example were as follows:

[0150] 1. A power supply for the entire apparatus was turned on. Under the control of the automatic detection/feeding controller 10, the on-site detection was conducted through various sensors. The detected data was transmitted to the automatic detection/feeding controller 10 for processing. After the processing, a command was issued according to a program to make each device run.

[0151] 2. A rotational speed of the variable-frequency fan 30 was reduced from the original 1,400 rpm to 1,300 rpm. The etching working solution 23 was fed into the etching machine 1, the anode cell zone of the electrolytic cell, and the solution mixing-exchange tank 17. The spent etching solution 22 was fed into the cathode cell zone. The pump 20-2 on the etching machine was started to make the etching working solution undergo an oxidation reaction with oxygen in air through spray atomization. Pumps 20-4 and 20-5 were started to make the etching working solution circularly flow between the etching machine 1 and the solution mixing-exchange tank 17. Pumps 20-6 and 20-7 were started to make a solution in the solution mixing-exchange tank 17 circularly flow between the solution mixing-exchange tank and the anode cell zone of the electrolytic cell.

[0152] 3. The printed circuit board to be etched 26 was fed into the etching machine for etching. An operation of the heat exchanger 11-1 was controlled based on data detected by the sensor 9-1 as a thermometer. A pump 20-1 was controlled to feed the etching replenisher based on data detected by the sensor 9-2 as a pH meter. A concentration of copper ions in the etching working solution was monitored by the sensor 9-3 as a gravimeter. An etching rate was adjusted according to a set value for the sensor 9-4 as an ORP meter. The heat exchanger 11-2 was controlled based on data detected by the sensor 9-5 as a thermometer to stabilize a temperature of the etching working solution. A pump 20-3 was controlled to discharge the spent etching solution 22 based on the sensor 9-6 as a liquid level meter. An operation of the electrolytic cell 2 was controlled based on data detected by the sensor 9-7 as an ORP meter. For the sensor 9-8 as an ORP meter, a safety threshold of 180 my was set as a safety interlock for the turn-off of the electrolytic power supply. A specific gravity value of 1.08 g/L was set for the sensor 9-9 as a gravimeter to control the feeding of the spent etching solution 22 into the cathode cell zone by a pump 20-10. During the electrolysis, a Cu(NH.sub.3).sub.2Cl complex in the anode electrolyte was oxidized into a copper-etching agent Cu(NH.sub.3).sub.4Cl.sub.2, and the metallic copper 28 was electrodeposited at the cathode.

[0153] 4. A polluted tail gas from each cell/tank in the apparatus was directed to the tail gas treatment device 27-2 for an environmental treatment. A tail gas from an etching machine was directed to the tail gas treatment device 27-1 with an adjustable exhaust air volume for a treatment, and a waste gas from the tail gas treatment device 27-1 was further directed to the tail gas treatment device 27-2 for an environmental treatment.

[0154] According to the etching working solutions shown in Table 1, an etching working solution was subjected to oxidative regeneration with the traditional spray-oxygen absorption system, in which case the rotational speed of the variable-frequency fan 30 was 1,400 rpm. A measured etching rate was recorded in Table 1. Then, the electrolysis apparatus was started, and with the oxidative regeneration scheme of traditional spray-oxygen absorption system+electrolytic oxidative regeneration apparatus in the present disclosure, the etching working solution was subjected to oxidative regeneration according to the above steps. A measured etching rate was recorded in Table 1.

[0155] According to the comparison of etching rates of the two processes in Example 5, the reduction in the supply of fresh air caused by the reduction in the rotational speed of the variable-frequency fan 30 in the traditional spray-oxygen absorption-exhausting system directly affects the chemical reaction of oxidatively regenerating the copper-etching agent. On this basis, an apparatus for electrolysis-assisted oxidative regeneration of the copper-etching agent was added, which could enhance the etching production efficiency while reducing the emission of an ammonia-containing waste gas to improve the environment. According to test results, in the present disclosure, after the electrolysis-assisted oxidation was adopted in combination with the adjustment of the spray-oxygen absorption system, an ammonia gas loss caused by extraction was reduced by 40%. When there was a low solution circulation flow rate between the anode cell zone of the electrolytic cell and the solution mixing-exchange tank, after long-term etching and electrolysis-assisted oxidative regeneration, contents of ammonia water, ammonium ions, ammonium carbonate, ammonium bicarbonate, and YH-510A in the etching working solution slightly decreased. When a solution circulation flow rate between the anode cell zone of the electrolytic cell and the solution mixing-exchange tank was increased or the solution circulation flow rate between the solution mixing-exchange tank and the anode cell zone of the electrolytic cell and a solution circulation flow rate between the solution mixing-exchange tank and the etching machine were increased, after long-term etching and electrolysis-assisted oxidative regeneration, contents of ammonia water, ammonium ions, ammonium carbonate, ammonium bicarbonate, and YH-510A in the etching working solution did not significantly change. Specific process parameters were listed in Table 1.

Example 6

[0156] The apparatus in Example 2 was adopted, and the method in Example 2 was repeated. This example was different from Example 2 in that: The electrolytic cell separator 3 was an ion selectivity-free membrane, and the turn-off of the electrolytic power supply 6 was controlled based on a value detected by the sensor 9-3 as an ORP meter and a set safety threshold of 300 mv.

[0157] According to the etching working solutions shown in Table 1, an etching working solution was subjected to oxidative regeneration with the traditional spray-oxygen absorption system. A measured etching rate was recorded in Table 1. Then, the electrolysis apparatus was started, and with the oxidative regeneration scheme of traditional spray-oxygen absorption system+electrolytic oxidative regeneration apparatus in the present disclosure, the etching working solution was subjected to oxidative regeneration according to the above steps. A measured etching rate was recorded in Table 1.

[0158] According to test results, when there was a low solution circulation flow rate between the anode cell zone of the electrolytic cell and the etching machine, after long-term etching and electrolysis-assisted oxidative regeneration, contents of ammonium ions, ammonium carbonate, and YH-510A in the etching working solution slightly decreased with a low decline rate, indicating controllability. When a solution circulation flow rate between the anode cell zone of the electrolytic cell and the etching machine was increased, after long-term etching and electrolysis-assisted oxidative regeneration, contents of ammonium ions, ammonium carbonate, and YH-510A in the etching working solution did not significantly change. In this example, when the effective electrolytic area of the electrolytic anode increased, after long-term etching and electrolysis-assisted oxidative regeneration, contents of ammonium ions, ammonium carbonate, and YH-510A in the etching working solution did not significantly change.

Example 7

[0159] The apparatus in Example 4 was adopted, and the method in Example 4 was repeated. This example was different from Example 4 in that: The electrolytic cell separator 3 was a proton exchange membrane, and for the sensor 9-6 as an ORP meter, a safety threshold of 100 my was set as a safety interlock for controlling the turn-off of the electrolytic power supply 6.

[0160] According to the etching working solutions shown in Table 1, an etching working solution was subjected to oxidative regeneration with the traditional spray-oxygen absorption system, in which case the gas flow-regulating valve 29 was fully open and the rotational speed of the variable-frequency fan 30 was 1,400 rpm. A measured etching rate was recorded in Table 1. Then, the electrolysis apparatus was started, and with the oxidative regeneration scheme of traditional spray-oxygen absorption system+electrolytic oxidative regeneration apparatus in the present disclosure, the etching working solution was subjected to oxidative regeneration according to the above steps. A measured etching rate was recorded in Table 1. Test results showed that, after long-term etching and electrolysis-assisted oxidative regeneration, contents of ammonia water, ammonium ions, and YH-510A in the etching working solution did not significantly change.

[0161] During an etching process, the etching replenisher was fed into the etching machine, the solution mixing-exchange tank, and the anode cell zone of the electrolytic cell separately for testing. An identical etching effect was achieved.

Comparative Example 1

[0162] The apparatus in Example 2 was adopted, and the method in Example 2 was repeated. This comparative example was different from Example 2 in that: The electrolytic cell separator 3 was an ion selectivity-free membrane, and the turn-off of the electrolytic power supply 6 was controlled based on a value detected by the sensor 9-3 as an ORP meter and a set safety threshold of 400 mv. This comparative example was different from Example 6 in that there was a different set safety threshold for the sensor 9-3 as an ORP meter.

[0163] According to test results, after long-term etching and electrolysis-assisted oxidative regeneration, contents of ammonium ions, ammonium carbonate, and YH-510A in the etching working solution significantly decreased. Even after a solution circulation flow rate between the anode cell zone of the electrolytic cell and the etching machine increased and the effective electrolytic area of the electrolytic anode increased, the additional consumption of the above components remained excessive and uncontrollable, making it difficult to maintain the stable composition of the etching working solution.

TABLE-US-00001 TABLE 1 Etching rate when the Etching rate when the oxidative oxidative regeneration regeneration is is conducted with the conducted with traditional spray- ORP value the traditional oxygen absorption of an Composition spray-oxygen system + the Etching working anode of a cathode absorption electrolytic oxidative Example solution electrolyte electrolyte system regeneration apparatus Remarks 1 Copper ion Upper 12% ammonia 56 m/min 64 m/min The original fully-open concentration: limit of a water opening of the gas flow- 170 g/L set value regulating valve 29 in the pH value: 8.4 for an traditional spray-oxygen ORP meter absorption-exhausting system 9-3: 150 remains unchanged mv 2 Copper ion Upper Copper ion 21 m/min 24 m/min The original fully-open concentration: 60 limit of a concentration opening of the gas flow- g/L set value in a copper- regulating valve 29 in the YH-510A for an ammonia traditional spray-oxygen concentration: ORP meter complex absorption-exhausting system 2.5 mol/L 9-3: 280 solution: remains unchanged pH value: 7 mv 70 g/L pH value: 8.2 3 Copper ion Upper 10% 51 m/min 52 m/min A rotational speed of the concentration: limit of a ammonium variable-frequency fan 30 is 140 g/L set value carbonate reduced from the original YH-510A for an solution 1,400 rpm to 1,200 rpm concentration: ORP meter 1.2 mol/L 9-5: 80 mv pH value: 8.2 4 Copper ion Upper Spent etching 60 m/min 61 m/min An opening of the gas flow- concentration: limit of a solution regulating valve 29 in the 110 g/L set value produced after traditional spray-oxygen YH-510A for an an etching absorption-exhausting system concentration: ORP meter operation in is reduced to 80% of the 0.00004 mol/L 9-6: 50 mv this example original fully-open opening, pH value: 9 and a rotational speed of the variable-frequency fan 30 is reduced from the original 1,400 rpm to 1,300 rpm 5 Copper ion Upper Spent etching 35 m/min 42 m/min A rotational speed of the concentration: 90 limit of a solution variable-frequency fan 30 is g/L set value produced after reduced from the original YH-510A for an an etching 1,400 rpm to 1,300 rpm concentration: ORP meter operation in 0.7 mol/L 9-8: 180 this example pH value: 7.4 mv 6 Copper ion Upper Copper ion 21 m/min 25 m/min The original fully-open concentration: 60 limit of a concentration opening of the gas flow- g/L set value in a copper- regulating valve 29 in the YH-510A for an ammonia traditional spray-oxygen concentration: ORP meter complex absorption-exhausting system 2.5 mol/L 9-3: 300 solution: 70 remains unchanged pH value: 7 mv g/L pH value: 8.2 7 Copper ion Upper Spent etching 60 m/min 63 m/min An opening of the gas flow- concentration: limit of a solution regulating valve 29 in the 110 g/L set value produced after traditional spray-oxygen YH-510A for an an etching absorption-exhausting system concentration: ORP meter operation in is reduced to 80% of the 0.00004 mol/L 9-6: 100 this example original fully-open opening, pH value: 9 mv and a rotational speed of the variable-frequency fan 30 is reduced from the original 1,400 rpm to 1,300 rpm