A chlorine gas fully automatic, safe and efficient regeneration acid etching liquid system

Abstract

The present invention provides a chlorine gas fully automatic safe and efficient acid etching liquid regeneration system, which belongs to the field of PCB industry printed circuit board acid waste liquid resource disposal technology. The system includes an etching system unit, a parameter detection system, a material addition system, a waste liquid automatic collection system, a waste liquid electrolysis system, a regeneration liquid automatic reuse system, a central control system and an alarm control system. The system can ensure the safe and efficient use of chlorine gas, and the chlorine gas regeneration reduces the use of oxidants by 60%-95%, reduces the use of hydrochloric acid by 40%-70%, and reduces the use of liquid alkali by 40%-70% in chlorine treatment, which has great economic value and environmental value.

Description

Technical Field

[0001] The invention belongs to the technical field of resource disposal of acid waste liquid of printed circuit boards in the PCB industry, and in particular to a chlorine gas fully automatic, safe and efficient acid etching liquid regeneration system. Background Art

[0002] Printed circuit boards are important electronic components and carriers that connect electronic components to achieve complex functions. Printed circuit boards have high integration and complex production processes. The basic principle is to connect various components through fine copper wires on different base materials to transmit signals. The copper wire production process described is mature. It mainly involves electroplating a layer of copper foil with a certain thickness on the base material in the early stage to meet the wire requirements of the circuit board, coating a layer of anti-etching material on the copper foil through photochemical principles, dissolving the unprotected copper foil with etching solution, and then dissolving the anti-etching material with other reagents to generate the designed circuit.

[0003] After continuous improvement, etching solutions have been developed into five common etching solutions, including acidic copper chloride etching solution, alkaline copper chloride etching solution, ferric chloride etching solution, and sulfuric acid / hydrogen peroxide etching solution. Among them, acidic copper chloride etching solution and alkaline copper chloride etching solution have the widest application range, the most mature development, and complete supporting etching equipment. The main components of acidic copper chloride etching solution are copper chloride, hydrochloric acid, sodium chloride, ammonium chloride and other trace auxiliary raw materials. The main components of alkaline copper chloride etching solution are copper chloride, ammonia water, ammonium chloride and other trace auxiliary raw materials. Acidic copper chloride etching solution (hereinafter referred to as "acidic etching solution") and alkaline copper chloride etching solution (hereinafter referred to as "alkaline etching solution") are used to etch different types of circuit boards according to their respective characteristics. The basic principle is that the divalent copper ions in the etching solution oxidize and dissolve the copper foil to generate monovalent copper ions, and the monovalent copper ions are oxidized to divalent copper ions by supplementing oxidants, while supplementing other consumable components to maintain the etching ability of the etching solution unchanged. Since the copper ion complex form of alkaline etching solution is relatively active, the monovalent copper ions generated during the etching process can be continuously oxidized by oxygen in the air, so there is no need to add liquid oxidant. However, the copper ion complex form of acidic etching solution cannot be quickly oxidized by oxygen in the air and cannot meet the requirements of high copper etching. Therefore, two types of etching solution systems, hydrochloric acid copper chloride plus sodium chlorate etching solution system and hydrochloric acid copper chloride plus hydrogen peroxide system, are derived. Oxidants and other consumable components need to be dynamically added during the etching process, which makes the acid etching control process more complicated than the alkaline etching process.

[0004] The main components of acid etching solution are copper chloride, hydrochloric acid, sodium chloride, ammonium chloride and other trace auxiliary raw materials. The copper ion concentration is as high as 120-160g / L, the hydrochloric acid content is 1.0-3.0mol / L, and the salt (sodium chloride and ammonium chloride) concentration is as high as 40-70g / L. It is a high-heavy metal, high-salt, and high-acid solution. There are currently two main disposal methods. One method is to separate and recover metallic copper, acid and salt; the other method is to recycle part of the solution, and the remaining solution is still used to separate and purify each component or to produce other products with more economic value.

[0005] Chinese patent CN201110231641.4 discloses a method for preparing copper oxide using an acidic etching solution as a raw material, wherein the acidic etching solution is adjusted to a pH of 10-13 with alkali, and then pure water is added and heated in a reaction tank at 120-200°C for 2-10 hours, and copper oxide is obtained after washing and drying. Chinese patent CN201610364240.9 discloses a method and device for preparing copper oxychloride using an acidic etching solution and an alkaline etching solution, wherein the acidic etching solution and the alkaline etching solution are controlled within a certain pH range, and are continuously added and neutralized, and the temperature is maintained at 48-51°C, and copper oxychloride is obtained after filtration and drying. Chinese patent CN201611161135.1 discloses a method for recovering hydrochloric acid by distillation, recovering sodium chloride by crystallization, and recovering copper by electrolysis. Chinese patent CN201921306790.0 discloses a system for producing copper sulfate from an acidic etching solution, which uses an alkaline etching solution to adjust the pH of the acidic etching solution to a certain range, and synthesizes copper sulfate through processes such as precipitation, filtration, thermal dissolution, suction filtration and crystallization, drying and stripping. The above methods all utilize chemical reactions and the differences in pH and temperature of various substances. The copper ions, hydrochloric acid, sodium chloride, ammonium chloride and other substances in the etching solution are separated by adding alkali and heating. The process control is relatively complicated, and more equipment is required, and the cost investment is relatively large. It does not have a competitive advantage for the acidic etching solution produced by small and medium-sized circuit board factories.

[0006] Chinese patent CN201920568685.8 discloses an acid etching solution electrolysis post-treatment system, in which the solution after electrolysis uses an ejector to absorb the chlorine generated during the electrolysis process, and after being adjusted, it is recycled. Chinese patent CN201720706793.8 discloses an acid etching solution resource recycling system, which uses a diffusion dialysis tank to separate hydrochloric acid to obtain a low-acid copper-containing solution, and the hydrochloric acid is reused in the etching production line. The low-acid copper-containing solution is extracted and stripped to obtain a copper-rich solution, and the copper-rich solution is electrolyzed to recover copper, and no chlorine is generated during the electrolysis process. Chinese patent CN201821003989.1 discloses a system for treating chlorine in a copper recovery system for recycling acidic etching liquid. The etching waste liquid is electrolyzed to recover copper. The electrolyzed etching liquid is concentrated and separated to produce high-acidity etching liquid and low-acidity etching liquid. The high-acidity etching liquid is directly used as etching liquid. The low-acidity etching liquid absorbs part of the chlorine through a jet and reuses it. The unabsorbed chlorine is absorbed by sodium hydroxide and finally discharged into the atmosphere through three-stage tail gas treatment. Chinese patent CN201921612913.3 discloses a chlorine resource utilization system in the recovery process of acidic etching liquid. The chlorine generated during the electrolysis process is connected to an oxidation spray tower, and the outlet of the oxidation spray tower is connected to a ferrous chloride spray tower, which is connected to a liquid alkali spray tower. The chlorine generated by electrolysis is oxidized to a ferrous chloride solution to form a ferric chloride solution through three-stage absorption. Most of the above patents use electrochemical methods to recover copper. The electrolytic method requires a single device to treat acidic etching solutions, and the process control is simple. It has obvious competitive advantages for small and medium-sized circuit board factories. However, the only disadvantage of the electrolytic method is that chlorine gas will be produced during the electrolysis process. Chlorine gas is highly oxidizing and toxic. In theory, it can be used as an oxidant to replace liquid oxidants such as sodium chlorate and hydrogen peroxide in the etching process to avoid the problem of volume expansion of the etching solution. However, the efficiency of ordinary ejectors for etching solutions to absorb chlorine gas is extremely low, mainly because the content of monovalent copper ions in the etching waste liquid is low, the acidity is high, and the contact area between chlorine and etching solution in the ejection process is small. The chlorine absorption efficiency is usually less than 50%. A large amount of unabsorbed chlorine in the reaction tank needs to be treated in time. The electrolytic method for regenerating and circulating acidic etching solutions still needs to solve the problems of chlorine utilization efficiency and safe use. Summary of the invention

[0007] Based on the above-mentioned acid copper chloride etching solution treatment method, the present invention adopts electrolysis to treat acid etching waste liquid, and the etching solution after electrolysis is automatically reused by adding effective ingredients. The chlorine generated by electrolysis is absorbed online with the etching solution by a continuous broken jet device, and the chlorine absorption efficiency is greatly improved by increasing the contact area between the chlorine and the etching solution. At the same time, the redox potential control method is adopted to ensure that chlorine replaces the liquid oxidant to the greatest extent. At the same time, in order to ensure the safety and reliability of the chlorine use process, an alarm control system is designed. The specific contents of the present invention are as follows:

[0008] The object of the present invention is to provide a chlorine gas fully automatic safe and efficient acid etching solution regeneration system, the technical point of which is that it includes an etching system unit, a parameter detection system, a material addition system, an automatic waste liquid collection system, a waste liquid electrolysis system, an automatic regeneration liquid recycling system, a central control system and an alarm control system;

[0009] The etching system unit is used to etch the copper foil of the circuit board to generate etching waste liquid;

[0010] The parameter detection system includes an oxidant detection system, a specific gravity detection system, and a hydrochloric acid detection system. The parameter detection system is used to detect parameter values ​​during operation of the etching system and send signals to the material addition system;

[0011] The material adding system includes a sodium chlorate adding system, a hydrochloric acid adding system, a regeneration liquid adding system, and a chlorine automatic control system. The material adding system is used to receive the signal sent by the parameter detection system and add corresponding materials according to the set parameter thresholds;

[0012] The automatic waste liquid collection system comprises an overflow device, a waste liquid collection transfer tank, and an etching waste liquid collection tank. The etching waste liquid generated during the working process of the etching system unit controls the total amount to enter the waste liquid collection transfer tank through the overflow device, and then transfers to the etching waste liquid collection tank;

[0013] The waste liquid electrolysis system includes an electrolytic cell, the electrolytic cell adopts positive and negative spaced electrode materials, and is connected to a DC power supply. The etching waste liquid in the waste liquid automatic collection system enters the electrolytic cell and forms a copper plate at the cathode through electrolysis, and chlorine is generated at the anode to enter the chlorine automatic control system. The chlorine automatic control system reacts in situ with the etching liquid in the etching system unit through a continuous broken jet device, wherein the suction end and the output end of the power pump of the chlorine absorption device are both etching liquid in the etching machine, and the higher temperature of the etching liquid in the etching tank can effectively improve the reaction activity of chlorine and cuprous ions, and oxidize the cuprous ions in the etching liquid to copper ions. The multi-stage (2-4-stage) crushing method of the series ejector can increase the negative pressure of chlorine gas extraction on the one hand, and can realize the long-distance reuse of chlorine; on the other hand, the multi-stage series connection can continuously crush the etching liquid to form smaller droplets, increase the contact specific surface area, and greatly improve the chlorine absorption efficiency. Through this design, the actual chlorine absorption efficiency is higher than 85%. In the waste liquid electrolysis system, the copper ion concentration in the etching waste liquid is lower than 15-80g / L during the electrolysis process. The electrolysis process can be performed by batch adding etching waste liquid and discharging electrolytic liquid, or by continuously replenishing etching waste liquid and discharging electrolytic liquid. Both methods use a specific gravity controller to continuously detect the specific gravity of copper ions in the electrolytic cell liquid and operate automatically. The electrolysis is performed for 5-10 days. When the electrolysis and liquid addition are stopped, the copper plate of the cathode is removed and the electrolysis is continued;

[0014] The automatic regeneration liquid recycling system is used to receive the electrolytic liquid discharged from the waste liquid electrolysis system and regenerate the etching liquid by adding sodium chloride or ammonium chloride into the regeneration liquid addition system;

[0015] The central control system is used to centrally receive and send signals from the etching system unit, the waste liquid electrolysis system, the regeneration liquid automatic recycling system, and the material addition system;

[0016] The alarm control system includes a high liquid level alarm and a chlorine detection alarm. The chlorine alarm system mainly detects the chlorine concentration in the etching tank exhaust pipeline and the chlorine in the etching machine environment. When the chlorine concentration exceeds a certain range, it indicates that chlorine has leaked, and the safety protection program is automatically triggered, the DC power supply current of the electrolytic cell is adjusted to 0A, the chlorine absorption device is turned off, and an alarm signal is issued at the same time. The alarm control system is used to add alarm detection equipment to the units with greater safety risks in the above-mentioned systems. When the alarm signal is triggered, the corresponding system unit and the associated system unit are immediately turned off to ensure the safe and stable operation of the entire system.

[0017] Furthermore, the oxidant detection system in the chlorine gas fully automatic, safe and efficient regeneration acid etching liquid system of the present invention is used to detect the redox potential value of the etching system unit and transmit the signal to the sodium chlorate addition system. Sodium chlorate is added through the regeneration liquid addition system to maintain the redox potential value balance of the etching system unit, so as to maintain the etching system unit to have a certain copper etching ability. The sodium chlorate of the present invention can be replaced by hydrogen peroxide to achieve the same technical effect.

[0018] Furthermore, the oxidant detection system in the chlorine fully-automatic, safe and efficient regeneration acid etching liquid system of the present invention is used to detect the redox potential value of the etching system unit and transmit the signal to the chlorine automatic control system, and chlorine is added through the regeneration liquid adding system to maintain the redox potential value balance of the etching system unit, so as to maintain the etching system unit to have a certain copper etching ability.

[0019] Furthermore, the specific gravity detection system in the chlorine gas fully automatic, safe and efficient regeneration acid etching liquid system of the present invention is used to detect the specific gravity value of the etching system unit and transmit the signal to the regeneration liquid addition system. The regeneration liquid addition system adds regeneration liquid to maintain the specific gravity value balance of the etching system unit to control the addition of low-copper solution, balance the copper ions dissolved by copper foil into the etching liquid, and prevent excessive copper ions in the etching system unit from reducing the etching rate.

[0020] Furthermore, the hydrochloric acid detection system in the chlorine gas fully automatic, safe and efficient regeneration acidic etching liquid system of the present invention is used to detect the acidity of the etching system unit and transmit the signal to the hydrochloric acid addition system, and hydrochloric acid is added by the hydrochloric acid addition system to maintain the acidity balance of the etching system unit.

[0021] Furthermore, the parameter detection system in the chlorine gas fully automatic, safe and efficient regeneration acid etching liquid system of the present invention also includes temperature detection and pressure detection, wherein the temperature detection is used to maintain the rapid progress of the entire chemical etching process, and the pressure detection is used to ensure that the etching liquid has sufficient contact with the copper foil of the circuit board.

[0022] Furthermore, in the chlorine gas fully automatic safe and efficient regeneration acid etching liquid system of the present invention, a high and low liquid level controller and an alarm controller are arranged in the waste liquid collection transfer tank. When the etching system unit continuously adds hydrochloric acid and low copper solution, the excess solution will be discharged by overflow and enter the waste liquid collection transfer tank. By arranging a high and low liquid level controller in the waste liquid collection transfer tank, the excess waste liquid is continuously discharged. At the same time, in order to avoid failure of high liquid level detection, an alarm detector and a wastewater overflow pipe are arranged above the high liquid level of the waste liquid collection transfer tank to ensure that the waste liquid of the etching tank can be discharged in time.

[0023] Furthermore, the electrolytic cell in the chlorine gas fully automatic, safe and efficient regeneration acidic etching solution system of the present invention includes an anode, an ion membrane, and a cathode. The anode is made of titanium as a substrate with a ruthenium or iridium-ruthenium coating on the surface, which can enhance conductivity and minimize current heating losses. The cathode is made of metallic titanium, which can effectively resist corrosion from acidic etching solutions.

[0024] Furthermore, in the chlorine fully automatic, safe and efficient regeneration acid etching liquid system of the present invention, the anode of the electrolytic cell is surrounded by a diaphragm frame, the ion membrane and the diaphragm frame form a sealed box, the diaphragm frame is immersed 5-10 mm below the liquid surface, one side of the diaphragm frame is opened and connected to the chlorine pipeline, and the chlorine generated by anode electrolysis can only be discharged into the chlorine automatic control system through the chlorine pipeline.

[0025] The present invention relates to a chlorine gas fully automatic, safe and efficient acid etching solution regeneration system, which has the following beneficial effects:

[0026] 1. This process uses electrolysis to treat acidic etching solution, with less equipment and simple control. It can also recover copper products with higher purity and has a wide range of applications.

[0027] 2. This process uses electrolysis to treat acidic etching liquid. The chlorine generated by the anode is absorbed in situ through a continuous broken jet device, which can greatly improve the chlorine absorption efficiency, reduce the use of liquid oxidants and hydrochloric acid, and greatly reduce operating costs;

[0028] 3. The entire process adopts automatic control in most links to maintain stable operation of the equipment. At the same time, alarms and interlocking controls are designed in key links to greatly improve the safety of automatic operation and reduce human operating errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A control flow chart of a chlorine gas fully automatic, safe and efficient regeneration acid etching solution system designed for the present invention;

[0030] Figure 2 Design diagram for a single anode device in an electrolytic cell.

[0031] In the figure: 1-anode; 2-chlorine gas pipeline; 3-sealing box; 301-diaphragm plate frame; 4-ion membrane. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0033] The acid etching liquid is treated by electrolysis, and electrolytic chlorine is used as an oxidant. The acid etching liquid is efficiently oxidized in multiple stages through a series of ejectors. The process parameters are continuously detected to control the equipment to automatically operate within a reasonable range. At the same time, for links with major safety risks, an alarm linkage control program is added. The automation level of the entire system exceeds 85%, and only a small number of managers are needed to inspect the parameters to achieve efficient operation. The following example explains in detail how the entire system can operate safely, efficiently and automatically.

[0034] Reference Figure 1 The control flow chart of a chlorine gas fully automatic safe and efficient acid etching solution regeneration system is shown, and the present invention includes an etching system unit, a parameter detection system, a material adding system, an automatic waste liquid collection system, a waste liquid electrolysis system, an automatic regeneration liquid recycling system, a central control system and an alarm control system;

[0035] The etching system unit is used to etch the copper foil of the circuit board, generating etching waste liquid;

[0036] The parameter detection system includes an oxidant detection system, a specific gravity detection system, and a hydrochloric acid detection system. The parameter detection system is used to detect parameter values ​​during operation of the etching system and send signals to the material addition system. Preferably, the parameter detection system of the present invention also includes temperature detection and pressure detection.

[0037] The material addition system includes a sodium chlorate addition system, a hydrochloric acid addition system, a regeneration liquid addition system, and a chlorine automatic control system. The material addition system is used to receive signals from the parameter detection system and add corresponding materials according to the set parameter thresholds. Preferably, the oxidant detection system of the present invention is used to detect the redox potential value of the etching system unit and transmit the signal to the sodium chlorate addition system, and sodium chlorate is added through the regeneration liquid addition system to maintain the redox potential value balance of the etching system unit. Preferably, the oxidant detection system of the present invention is used to detect the redox potential value of the etching system unit and transmit the signal to the chlorine automatic control system, and chlorine is added through the regeneration liquid addition system to maintain the redox potential value balance of the etching system unit. Preferably, the specific gravity detection system of the present invention is used to detect the specific gravity value of the etching system unit and transmit the signal to the regeneration liquid addition system, and the regeneration liquid is added through the regeneration liquid addition system to maintain the specific gravity value balance of the etching system unit. Preferably, the hydrochloric acid detection system of the present invention is used to detect the acidity of the etching system unit and transmit the signal to the hydrochloric acid addition system, and hydrochloric acid is added through the hydrochloric acid addition system to maintain the acidity balance of the etching system unit.

[0038] The automatic waste liquid collection system includes an overflow device, a waste liquid collection transfer tank, and an etching waste liquid collection tank. The etching waste liquid generated during the working process of the etching system unit controls the total amount to enter the waste liquid collection transfer tank through the overflow device, and then transfers to the etching waste liquid collection tank. Preferably, a high and low liquid level control meter and an alarm controller are set in the waste liquid collection transfer tank of the present invention.

[0039] The waste liquid electrolysis system includes an electrolytic cell, which is connected to a DC power supply. The etching waste liquid in the waste liquid automatic collection system enters the electrolytic cell and forms a copper plate at the cathode through electrolysis. Chlorine gas is generated at the anode and enters the chlorine gas automatic control system. The chlorine gas automatic control system reacts in situ with the etching liquid in the etching system unit through a continuous broken jet device. The copper ion concentration in the etching waste liquid in the waste liquid electrolysis system is lower than 15-80g / L during the electrolysis process. Preferably, the electrolytic cell of the present invention includes an anode 1, an ion membrane 4, and a cathode. The anode 1 is made of titanium as a substrate and coated with ruthenium or iridium-ruthenium coating on the surface. The cathode is made of metallic titanium. Figure 2 As shown, as a preferred embodiment, the anode 1 of the electrolytic cell of the present invention is surrounded by a diaphragm frame 301, the ion membrane 4 and the diaphragm frame 301 form a sealed box 3, the diaphragm frame 301 is immersed 5-10 mm below the liquid surface, and a hole on one side of the diaphragm frame 301 is connected to the chlorine pipeline 2.

[0040] The regeneration liquid automatic recycling system is used to receive the electrolytic liquid discharged from the waste liquid electrolysis system and regenerate the etching liquid by adding sodium chloride or ammonium chloride into the regeneration liquid addition system;

[0041] The central control system is used to centrally receive and send signals from the etching system unit, waste liquid electrolysis system, regeneration liquid automatic recycling system, and material addition system;

[0042] The alarm control system includes high liquid level alarm and chlorine gas detection alarm. The alarm control system is used to add alarm detection equipment to the units with greater safety risks in the above-mentioned systems. When the alarm signal is triggered, the corresponding system unit and related system units are immediately shut down to ensure the safe and stable operation of the entire system.

[0043] The specific explanation is as follows:

[0044] The etching system unit of the present invention includes an etching machine, an etching liquid and a detection device. The etching machine power device fully contacts the etching liquid with the copper foil of the circuit board, and the etching liquid removes the part of the circuit board that is not protected by the anti-corrosion. The principle is as follows:

[0045] CuCl 2+ +Cu→2CuCl

[0046] The divalent copper ions in the etching solution are reduced to monovalent copper ions. When the monovalent copper ions in the etching solution exceed 2g / L, the etching rate decreases significantly. The corresponding parameter is the decrease in the redox potential value. When the oxidant detection system detects that the redox potential is lower than the set value, such as 480mV, the oxidant detection system sends an oxidant addition signal. At this time, the oxidant addition signal will trigger the sodium chlorate automatic control system and the sodium chlorate addition system. Both chlorine and sodium chlorate can be used as oxidants to oxidize monovalent copper ions. The two oxidation principles are as follows:

[0047] Sodium chlorate oxidation principle:

[0048] 6CuCl+NaClO3+6HCl→6CuCl2+3H2O+NaCl

[0049] Chlorine oxidation principle:

[0050] 2CuCl+Cl2→2CuCl2

[0051] From the reaction equation, it can be found that sodium chlorate will consume hydrochloric acid when oxidizing monovalent copper ions, while chlorine gas can directly oxidize monovalent copper ions. Using sodium chlorate as an oxidant requires not only the addition of sodium chlorate, but also a large amount of hydrochloric acid, which causes the volume of the etching solution to expand. Chlorine gas, as an oxidant, does not cause an increase in volume, so it has a great advantage.

[0052] The oxidant addition signal of this system triggers the chlorine automatic control system and the sodium chlorate addition system at the same time. The electrolysis system generates chlorine gas, which is pumped from the anode to the jet device through the continuous broken jet device. The jet device extracts etching liquid from the waste liquid area of ​​the etching tank. In the mixing area of ​​the ejector, chlorine reacts with monovalent copper ions. The ejector has a good breaking and mixing effect. Through the series connection of 3-stage ejectors, the chlorine gas generated by electrolysis can completely oxidize the monovalent copper ions in the jet area. At the same time, part of the chlorine gas is broken into small bubbles and dissolved in the etching liquid. The effluent enters the etching tank. The chlorine gas dissolved in the solution can further oxidize the monovalent copper ions in the etching tank. When the oxidant detection system detects that the redox potential is higher than the set value, such as 600mV, the jet device is stopped, and the liquid alkali jet absorption device is turned on at the same time to make the excess chlorine gas into bleaching water. In order to prevent excess chlorine from remaining in the etching machine, a chlorine gas detection alarm device is installed in the exhaust pipe or other locations of the etching machine, and the chlorine gas detection signal is linked to the DC power supply for control. When the etching machine produces certain thick copper foil circuit boards, when chlorine oxidation cannot effectively oxidize all monovalent copper ions, the sodium chlorate addition system is triggered, and the etching ability of the etching solution is restored by adding sodium chlorate.

[0053] During the etching process, the generated monovalent copper ions exist in the form of cuprous chloride, which is insoluble. The cuprous chloride precipitation on the surface of the copper foil will hinder the further etching of the copper ions. A certain amount of hydrochloric acid needs to be added to complex the monovalent copper ions to form a dissolved state [CuCl3]. — Ions; As the copper foil dissolves, the copper ions in the etching solution continue to increase, and the specific gravity continues to rise. When the copper ion content exceeds a certain level, the etching rate will be significantly reduced. The specific gravity detection system sends a signal to the regeneration liquid addition system, and the regeneration liquid addition system starts the addition pump to input the electrolytic clearing liquid into the etching tank to maintain a stable copper ion content.

[0054] The addition of hydrochloric acid and electrolyte causes the volume of the etching tank liquid to expand, and the waste liquid continuously overflows into the waste liquid collection transfer tank. The waste liquid transfer tank is equipped with a high and low liquid level controller. When the waste liquid transfer tank reaches the high liquid level, the transfer pump is started to transfer the waste liquid to the waste liquid storage tank. When the waste liquid transfer tank reaches the low liquid level, the transfer pump is stopped. In order to avoid high liquid level detection failure, an alarm detector and a wastewater overflow pipe are set above the high liquid level of the waste liquid collection transfer tank to ensure that the waste liquid in the etching tank can be discharged in time.

[0055] The waste liquid electrolysis system uses a titanium cathode and titanium plated with ruthenium as an anode. The positive and negative plates are arranged at intervals. At the same time, all cathode plates are connected to the negative pole of the DC power supply, and all anodes are connected to the positive pole of the DC power supply. The DC power supply uses a type that can transmit and receive communication signals. When the chlorine gas detection alarm detects that the chlorine concentration exceeds a certain content, such as 0.5ppm, the DC power supply current is adjusted to 0A, and the etching production line chlorine absorption jet device is turned off, and the drift water jet absorption device is turned on.

[0056] During the electrolysis process, the copper ions in the etching solution are continuously reduced to copper by cathode electrons to form copper plate products, and the chloride ions at the anode are converted into chlorine gas, which is continuously used through the chlorine gas collection pipeline and ejector. During the electrolysis process, the copper ions in the etching solution are continuously reduced. A specific gravity sampling device is installed in the electrolytic cell. When the copper ion concentration is lower than 50g / L, the electrolytic liquid discharge pump is turned on to discharge one-third of the electrolytic liquid at a time. Through liquid level control, the waste liquid collection bucket delivery pump is started to transport the waste liquid to the electrolytic cell. When the waste liquid in the electrolytic cell reaches the original height, the waste liquid delivery pump is stopped and the electrolysis process is recirculated. Since the electrolytic liquid produced by electrolysis is converted into chlorine gas, sodium chloride or ammonium chloride needs to be added. This process is completed by the stirring device to complete the solution preparation, and then it can be returned to the etching production line to adjust the specific gravity. Through the above control, the entire process can automatically realize the electrolysis and recycling of etching waste liquid, and the chlorine gas produced by electrolysis can be safely and efficiently utilized through the continuous crushing ejector device and chlorine alarm control.

[0057] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A chlorine gas fully automatic, safe and efficient acid etching solution regeneration system, characterized in that: It includes etching system unit, parameter detection system, material adding system, waste liquid automatic collection system, waste liquid electrolysis system, regeneration liquid automatic recycling system, central control system and alarm control system; The etching system unit is used to etch the copper foil of the circuit board to generate etching waste liquid; The parameter detection system includes an oxidant detection system, a specific gravity detection system, and a hydrochloric acid detection system. The parameter detection system is used to detect parameter values ​​during operation of the etching system and send signals to the material addition system; The material adding system includes a sodium chlorate adding system, a hydrochloric acid adding system, a regeneration liquid adding system, and a chlorine automatic control system. The material adding system is used to receive the signal sent by the parameter detection system and add corresponding materials according to the set parameter thresholds; The automatic waste liquid collection system comprises an overflow device, a waste liquid collection transfer tank, and an etching waste liquid collection tank. The etching waste liquid generated during the working process of the etching system unit controls the total amount to enter the waste liquid collection transfer tank through the overflow device, and then transfers to the etching waste liquid collection tank; The waste liquid electrolysis system comprises an electrolytic cell, which is connected to a DC power supply. The etching waste liquid in the waste liquid automatic collection system enters the electrolytic cell and forms a copper plate at the cathode through electrolysis, and generates chlorine at the anode and enters the chlorine automatic control system. The chlorine automatic control system reacts in situ with the etching liquid in the etching system unit through a continuous broken jet device. In the waste liquid electrolysis system, the etching waste liquid is discharged when the copper ion concentration is lower than 15-80 g / L during the electrolysis process; The automatic regeneration liquid recycling system is used to receive the electrolytic liquid discharged from the waste liquid electrolysis system and regenerate the etching liquid by adding sodium chloride or ammonium chloride into the regeneration liquid addition system; The central control system is used to centrally receive and send signals from the etching system unit, the waste liquid electrolysis system, the regeneration liquid automatic recycling system, and the material addition system; The alarm control system includes a high liquid level alarm and a chlorine gas detection alarm. The alarm control system is used to add alarm detection equipment to the units with greater safety risks in the above-mentioned systems. When the alarm signal is triggered, the corresponding system unit and the associated system unit are immediately shut down to ensure the safe and stable operation of the entire system; The oxidant detection system is used to detect the redox potential value of the etching system unit and transmit the signal to the sodium chlorate addition system, and sodium chlorate is added through the regeneration liquid addition system to maintain the redox potential value balance of the etching system unit; The oxidant detection system is used to detect the redox potential value of the etching system unit and transmit the signal to the chlorine automatic control system, and add chlorine through the regeneration liquid addition system to maintain the redox potential value balance of the etching system unit; The specific gravity detection system is used to detect the specific gravity value of the etching system unit and transmit the signal to the regeneration liquid adding system, and the regeneration liquid is added through the regeneration liquid adding system to maintain the specific gravity value balance of the etching system unit; The hydrochloric acid detection system is used to detect the acidity of the etching system unit and transmit the signal to the hydrochloric acid addition system, and the hydrochloric acid is added by the hydrochloric acid addition system to maintain the acidity balance of the etching system unit; The parameter detection system also includes temperature detection and pressure detection; A high and low liquid level controller and an alarm controller are arranged in the waste liquid collection transfer tank; The electrolytic cell comprises an anode (1), an ion membrane (4), and a cathode. The anode (1) is made of titanium as a substrate with a ruthenium or iridium-ruthenium coating on the surface, and the cathode is made of metallic titanium. The anode (1) of the electrolytic cell is surrounded by a diaphragm frame (301), the ion membrane (4) and the diaphragm frame (301) form a sealed box (3), the diaphragm frame (301) is immersed 5-10 mm below the liquid surface, and a hole on one side of the diaphragm frame (301) is connected to the chlorine pipeline (2); When the copper ion concentration is lower than 50g / L, the electrolytic clear liquid discharge pump is turned on to discharge one-third of the electrolytic clear liquid at a time. Through liquid level control, the waste liquid collection bucket delivery pump is started to deliver the waste liquid to the electrolytic cell. When the electrolytic cell waste liquid reaches the original height, the waste liquid delivery pump is stopped and the electrolysis process is recirculated. The electrolytic clear liquid generated by electrolysis needs to be supplemented with sodium chloride or ammonium chloride because chloride ions are converted into chlorine gas. This process is completed by the stirring device to complete the solution preparation, and then it can be returned to the etching production line to adjust the specific gravity. The entire process is automatically controlled by the above control to realize the electrolysis and recycling of etching waste liquid, and the chlorine gas generated by electrolysis is safely and efficiently utilized through the continuous crushing jet device and chlorine alarm control. The continuous crushing jet device adopts a multi-stage crushing method of series ejectors.

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