TWI726677B - Method and system for regenerating acid etching waste liquid - Google Patents

Abstract

A method for regenerating an acid etching waste liquid includes the following steps. (i) An etching solution to be processed including copper ions, cuprous ions, and chloride ions is provided. (ii) The etching solution to be processed is transferred to an electrolytic cell for electrolytic reaction to obtain an electrolytic regeneration solution, in which the anode of the electrolytic cell converts cuprous ions into copper ions and chloride ions into chlorine gas, and the cathode of the electrolytic cell converts copper ions into copper metal, in which a concentration of the cuprous ions in the electrolytic regeneration solution is lower than a concentration of cuprous ion in the etching solution to be processed. (iii) The chlorine gas obtained from the anode reacts with the electrolytic regeneration solution to convert the cuprous ion in the electrolytic regeneration solution to copper ions thereby obtaining a regenerated acid etching solution. (iv) The regenerated acid etching solution is transferred to a wet etching machine for use.

Description

Method and system for regenerating acid etching waste liquid

The present invention relates to a method and system for regenerating waste acid etching liquid. Especially with regard to the acid etching waste liquid used for circuit board structure.

Printed Circuit Board (PCB) is a pattern made of electronic wiring connecting circuit parts according to the circuit design, and then subjected to specific mechanical processing, processing and other processes to reproduce the electronic conductors on the insulator. The main purpose of the circuit board is to make the electronic parts arranged on the circuit board function through the circuit on the circuit board.

At present, the pattern etching of the inner and outer layers of PCB usually uses an acidic etching solution. The waste solution after etching is rich in cuprous ions, copper ions, and chloride ions. Direct sales or discharge will cause waste of resources and environmental protection problems, and it is used for acid The purchase cost of the oxidizer of the etching solution continues to be high. Therefore, there is an urgent need for a method and system that can effectively regenerate the acid etching waste liquid.

In various embodiments of the present invention, the cuprous acid in the acid etching waste liquid Ion electrolysis is regenerated into copper ions, and metallic copper can be precipitated at the cathode, optionally adding a small amount of etching additives, and then reused on the etching production line to achieve the purpose of regenerating the waste liquid.

In various embodiments of the present invention, a method for manufacturing a circuit board structure includes the following steps: (i) providing an etching solution to be processed, including copper ions, cuprous ions, and chloride ions; (ii) transferring the etching solution to be processed The electrolytic cell undergoes an electrolysis reaction to obtain an electrolytic regeneration solution. The anode of the electrolytic cell converts cuprous ions into copper ions and chlorine ions into chlorine gas, and the cathode of the electrolytic cell converts copper ions into copper metal, and the electrolytic regeneration solution The concentration of cuprous ions in the etching solution to be treated is lower than the concentration of cuprous ions in the etching solution to be processed; (iii) the chlorine gas obtained from the anode is reacted with the electrolytic regeneration solution to convert the cuprous ions in the electrolytic regeneration solution to copper ions to obtain regeneration Acid etching solution; and (iv) transferring the regenerated acid etching solution to the wet etching machine for use.

In many embodiments of the present invention, step (iii) further includes sending unreacted chlorine gas to a chlorine gas absorber to be absorbed.

In many embodiments of the present invention, before step (iv), an etching additive is added to the regenerated acid etching solution.

In many embodiments of the present invention, the etching solution to be processed contains CuCl ₂ .

In many embodiments of the present invention, the etching solution to be processed contains HCl.

In many embodiments of the present invention, a system for regenerating acid etching waste liquid includes: a first storage tank, an electrolytic tank, and a gas-liquid reactor. The first storage tank is configured to store the etching solution to be processed; the electrolytic tank is configured to receive the etching solution to be processed The etching solution is processed, and the etching solution to be processed is electrolytically reacted, wherein the electrolytic tank includes a gas outlet and a liquid outlet; a gas-liquid reactor is configured to process the etching solution to be processed through the electrolysis reaction to obtain a regenerated acid etching solution, gas-liquid reaction The device includes: a first liquid inlet, a second liquid inlet, a gas inlet, and a first liquid outlet. The first liquid inlet is connected to the liquid outlet of the electrolytic cell to receive the etching solution to be treated after the electrolysis reaction; the second liquid inlet is connected to the acid etching waste liquid supply source; the gas inlet is connected to the gas outlet of the electrolytic cell; and the first liquid The outlet is configured to output the regenerated acid etching solution.

In many embodiments of the present invention, a second storage tank is further included. The inlet of the second storage tank is connected to the liquid outlet of the electrolytic tank to receive the etching solution to be treated after the electrolysis reaction, and the outlet of the second storage tank is connected to The first liquid inlet of the gas-liquid reactor.

In many embodiments of the present invention, a chlorine gas absorber is further included, configured to absorb chlorine gas, and the chlorine gas absorber includes: a chlorine gas inlet connected to the gas outlet of the electrolytic cell.

In many embodiments of the present invention, the gas-liquid reactor further includes a gas outlet and a second liquid outlet. The gas outlet is connected to the chlorine inlet of the chlorine absorber; and the second liquid outlet is connected to the first storage tank.

In many embodiments of the present invention, the first liquid outlet of the gas-liquid reactor is connected to the wet etching machine.

Hereinafter, the above description will be described in detail by way of implementation, and a further explanation will be provided for the technical solution of the present invention.

102: first storage tank

103: Electrolyzer

1030: Recycling copper metal unit

103A: anode chamber

103B: Cathode chamber

104: Gas-liquid reactor

105: second storage tank

106: Chlorine Absorber

107: Wet etching machine

108: Acid etching waste liquid supply source

109: Specific gravity controller

110: Etchant storage tank

31G: Gas outlet

31L: Liquid outlet

41L: first liquid inlet

41LE: The first liquid outlet

41G: gas inlet

41GL: Gas outlet

42L: second liquid inlet

42LE: second liquid outlet

500: Regenerated acid etching waste liquid system

51L: entrance

51LE: Exit

61G: Chlorine gas inlet

S102, S104, S106, S108: steps

M100: method

In order to make the above and other objectives, features, advantages, and embodiments of the present invention more obvious and understandable, please read the following detailed description and match the corresponding drawings.

Fig. 1 is a system for regenerating acid etching waste liquid according to some embodiments of the present invention.

FIG. 2 is a flowchart of a method for regenerating the acid etching waste liquid using the system depicted in FIG. 1 according to some embodiments of the present invention.

In the implementation and the scope of the patent application, unless the article is specifically limited in the context, "a" and "the" can generally refer to a single or plural.

Regarding the terms "about", "approximately" or "approximately" used in this article, generally the error or range of the index value is generally within about 20%, preferably within about 10%, more preferably It is within about five percent.

FIG. 1 shows a system 500 for regenerating acid etching waste liquid according to some embodiments of the present invention. Please refer to FIG. 1, the regeneration acid etching waste liquid system 500 includes a first storage tank 102, an electrolytic tank 103, a gas-liquid reactor 104, and a wet etching machine 107. The wet etching machine 107 contains an acid etching solution for the etching process of the inner and outer layers of the printed circuit board. The first storage tank 102, the electrolytic tank 103, and the gas-liquid reactor 104 are configured to regenerate the used acid etching solution.

The first storage tank 102 is configured to store the etching solution to be processed. In some embodiments, the etching solution to be processed includes copper ions (Cu ²⁺ ), cuprous ions (Cu ⁺ ), and chloride ions (Cl ⁻ ). In other embodiments, the etching solution to be processed contains CuCl ₂ . In a specific embodiment, the etching solution to be processed contains HCl.

The electrolytic tank 103 is configured to receive the etching solution to be processed, and to perform an electrolytic reaction on the etching solution to be processed. As shown in FIG. 1, the electrolytic tank 103 is connected to the first storage tank 102. In many embodiments, the etching solution to be processed is transferred from the first storage tank 102 to the electrolytic tank 103 for electrolysis reaction, so as to obtain the electrolytic regeneration solution.

In detail, a membrane electrolysis (Membrane Electrolysis) process is used, which uses a micro-permeable membrane (not shown) to divide the electrolytic cell 103 into an anode chamber 103A and a cathode chamber 103B. When the etching solution to be processed enters the electrolytic cell 103, under the action of electric current, as shown in formula 1, the anode of the electrolytic cell converts cuprous ions into copper ions; as shown in formula 2, the anode of the electrolytic cell converts chloride ions It is chlorine gas; and as shown in formula three, the cathode of the electrolytic cell converts copper ions into copper metal.

A ^{formula: Cu + → Cu 2+ + e} -

Two _{^{formulas: 2Cl - → Cl 2 + 2e}} -

Three-: Cu ²⁺ + 2e ^- → Cu

Referring to Fig. 1 again, the electrolytic cell 103 includes a gas outlet 31G and a liquid outlet 31L. The gas outlet 31G is configured to transport the chlorine gas out of the anode chamber 103A, and the liquid outlet 31L is configured to transport out the anode chamber 103A 的electrolyte regeneration solution.

It is worth noting that the present invention provides at least three effects through the above-mentioned electrolysis reaction. The first effect is that in the copper etching reaction of the inner and outer layers of the printed circuit board, the copper ion has the etching ability, but the cuprous ion does not have the etching ability. Through the electrolysis reaction, the cuprous ions of the etching solution to be processed are converted into copper ions, thereby regenerating the etching ability of the etching solution to be processed. In many embodiments, after electrolysis, the concentration of cuprous ions in the electrolytic regeneration solution is lower than the concentration of cuprous ions in the etching solution to be processed. Table 1 shows the concentration of the etching solution to be processed before and after electrolysis. As shown in Table 1, compared with before electrolysis, the concentration of cuprous ions in the electrolytic etching solution after electrolysis has decreased.

On the other hand, the metallic copper deposited at the cathode during electrolysis has economic value. As shown in Figure 1, the copper metal unit 1030 can be recycled and sold or used in other process stages to save costs. This is the second effect.

The third function is that the chlorine gas obtained during electrolysis can be returned to the regenerated acid etching waste liquid system 500 as the oxidant of the electrolytic regenerated liquid, so that The cuprous ion concentration of the obtained electrolytic regeneration solution is further reduced, which will be described in detail below. Using the chlorine produced by the electrolysis reaction as the oxidant of the electrolytic regenerating solution can effectively reduce the purchase of oxidants and save production costs.

Referring to Fig. 1 again, the gas-liquid reactor 104 is configured to treat the etching solution to be treated (ie, the electrolytic regenerating solution) that undergoes the electrolysis reaction to obtain a regenerated acid etching solution. The gas-liquid reactor 104 includes a first liquid inlet 41L, a gas inlet 41G, a first liquid outlet 41LE, and a second liquid inlet 42L.

The first liquid inlet 41L of the gas-liquid reactor 104 is connected to the liquid outlet 31L of the electrolytic tank 103 to receive the etching liquid to be treated after the electrolysis reaction. The gas inlet 41G of the gas-liquid reactor 104 is connected to the gas outlet 31G of the electrolytic cell to receive the chlorine gas generated by the electrolysis reaction. In detail, the chlorine gas obtained from the anode chamber 103A and the electrolytic regeneration solution are reacted in the gas-liquid reactor 104, as shown in Equation 4, to convert the cuprous ions in the electrolytic regeneration solution to copper ions to obtain a regenerated acid etching solution.

Formula 4: 2CuCl+Cl ₂ → 2CuCl ₂

It is worth noting that the cuprous ions in the electrolytic regeneration solution react with chlorine in the gas-liquid reactor to produce copper ions with etching ability. In other words, chlorine is used as an oxidant to oxidize the electrolytic regeneration solution to make the copper ion concentration Get promoted again. In many embodiments, the concentration of copper ions in the regenerated acid etching solution is greater than the concentration of copper ions in the electrolytic regeneration solution.

The regenerated acid etching waste liquid system 500 may further include a second storage tank 105 including an inlet 51L and an outlet 51LE. The second storage tank 105 is equipped Set to store electrolytic regeneration solution. The inlet 51L of the second storage tank is connected to the liquid outlet 31L of the electrolysis tank to receive the etching solution to be processed by the electrolysis reaction, and the outlet 51LE of the second storage tank is connected to the first liquid inlet 41L of the gas-liquid reactor 104 to receive the electrolysis. Regeneration fluid.

Continuing to refer to FIG. 1, the first liquid outlet 41LE of the gas-liquid reactor 104 is configured to output the regenerated acid etching solution, and the regenerated acid etching solution is sent to the wet etching machine 107 for use. In many embodiments, the reaction performed in the wet etching machine 107 is as shown in formula 5. After the metal copper on the copper clad plate (not shown) reacts with copper chloride, copper ions with etching ability are consumed, and Generate cuprous ions without etching ability.

Formula 5: Cu+CuCl ₂ → 2CuCl

The regenerated acid etching waste solution system 500 may further include a specific gravity controller 109 configured to control the flow rate of the regenerated acid etching solution added to the wet etching machine 107 to adjust the specific gravity of the etching solution of the wet etching machine 107.

In some embodiments, before transferring the regenerated acid etching solution to the wet etching machine for use, optionally, an etching additive (not shown) is added to the regeneration acid etching solution. In some embodiments, the etching additive includes an oxidizing agent. In other embodiments, the etching additive includes a surfactant.

The regenerated acid etching waste liquid system 500 may further include an acid etching waste liquid supply source 108, and the second liquid inlet 42L of the gas-liquid reactor 104 is connected to the acid etching waste liquid supply source 108. The acid etching waste liquid supply source 108 is configured to control the waste liquid sent from the wet etching machine 107 to the gas-liquid reactor 104 flow.

The gas-liquid reactor 104 further includes a second liquid outlet 42LE. The second liquid outlet 42LE is connected to the first storage tank 102. In detail, the waste liquid after being used by the wet etching machine 107 can be sent to the gas-liquid reactor 104 via the acid etching waste liquid supply source 108, and then reacted with the chlorine oxygen in the gas-liquid reactor 104 after the formula 4 It is sent to the first storage tank 102 via the second liquid outlet 42LE to be recovered and regenerated again.

The regenerated acid etching waste liquid system 500 may further include a chlorine gas absorber 106 configured to absorb unreacted chlorine gas. The chlorine gas absorber 106 includes a chlorine gas inlet 61G to receive the chlorine gas from the anode and the chlorine gas absorber 106. In detail, part of the chlorine generated by the anode is sent to the chlorine absorber 106 for reaction, and then the unreacted chlorine is sent to the chlorine absorber 106 to be absorbed, and the other part is sent directly from the anode chamber to the chlorine gas. The absorber 106 is absorbed.

For the above purpose, the gas-liquid reactor 104 further includes a gas outlet 41GL. The gas outlet 41GL of the gas-liquid reactor 104 is connected to the chlorine inlet 61G of the chlorine absorber 106, and the unreacted chlorine in the chlorine absorber 106 is transferred to the chlorine absorber 106 and absorbed. The chlorine gas inlet 61G of the chlorine gas absorber 106 is connected to the gas outlet 31G of the electrolytic cell, and the chlorine gas generated in the anode chamber 103B is directly transmitted to the chlorine gas absorber 106 to be absorbed.

In some embodiments, the chlorine gas absorber may be an iron absorption cylinder, which includes ferrous chloride, ferric chloride, and iron filings. As shown in formula 6, chlorine gas reacts with ferrous chloride to produce ferric chloride; as shown in formula 7, ferric chloride reacts with iron filings. Instead, regenerate ferrous chloride. In many embodiments, the ferric chloride can be recovered and sold.

Formula 6: 2FeCl ₂ +Cl ₂ → 2FeCl ₃

Formula 7: Fe+ _{2FeCl 3} →3FeCl ₂

The system for regenerating the acid etching waste liquid of various embodiments of the present invention may further include an etchant storage tank 110 configured to store the etchant and communicate with the wet etching machine 107. The etchant may be transferred from the etchant storage tank to the wet etcher 107 to maintain the concentration of the etchant. In various embodiments, the etchant includes HCl. In various embodiments, the etchant includes an oxidizing agent.

FIG. 2 is a flowchart of a method for regenerating the acid etching waste liquid using the system depicted in FIG. 1 according to some embodiments of the present invention. The method M100 includes step S102, step S104, step S106, and step S108.

The method M100 starts at step S102. As shown in FIG. 1, an etching solution to be processed is provided, which includes copper ions, cuprous ions, and chloride ions. Step S104 is followed by step S102. As shown in Figure 1, the etching solution to be processed is transferred to the electrolytic cell for electrolysis to obtain an electrolytic regenerating solution, wherein the anode of the electrolytic cell converts cuprous ions into copper ions and changes chloride ions As chlorine gas, the cathode of the electrolytic cell converts copper ions into copper metal, and the concentration of cuprous ions in the electrolytic regeneration solution is lower than the concentration of cuprous ions in the etching solution to be processed. Step S106 is followed by step S104. As shown in Figure 1, the chlorine gas obtained from the anode is reacted with the electrolytic regenerating solution to convert the cuprous ions in the electrolytic regenerating solution to copper ions to obtain a regenerated acid etching solution. Step S108 Follow-up steps S106, as shown in Figure 1, transfer the regenerated acid etching solution to the wet etching machine for use. In some embodiments, step S106 further includes sending unreacted chlorine gas to a chlorine gas absorber for absorption. In some embodiments, before step S108, an etching additive is added to the regenerated acid etching solution.

The technology for regenerating acid etching waste liquid of the present invention adopts a diaphragm electrolysis process. The electrolytic cell is divided into a cathode chamber and an anode chamber through a micro-permeable membrane. When the etching solution to be processed enters the electrolytic cell, the electrolytic reaction is carried out under the action of electric current. In the anode chamber, the anode changes chlorine ions into chlorine gas, and cuprous ions into copper ions, so that the etching ability of the etching solution can be regenerated; in the cathode chamber, the by-product metallic copper with economic value is precipitated. Furthermore, the electrolytic regeneration solution reacts with the chlorine produced by the anode to further increase the concentration of copper ions with etching ability in the electrolytic regeneration solution. The regeneration etching solution is added to the wet etching machine through the specific gravity automatic controller to adjust the specific gravity of the etching solution in the wet etching machine. In summary, the dual purpose of copper recovery and loop regeneration of the acid copper chloride etching solution is achieved.

The system for regenerating acid etching waste liquid of the present invention provides the following features and advantages. (1) Reduce the amount of waste liquid treatment: 100% of the etching waste liquid will be electrolyzed, and only about 5% of the electrolyzed waste liquid needs environmental protection treatment. (2) Increasing copper output: At present, the etching waste liquid is rich in copper (about 150g/L), and electrolysis can electrolyze 95% of the copper ions into metallic copper. (3) Reduce the purchase of oxidants: use the chlorine produced by electrolysis as the oxidant, which effectively reduces the purchase of oxidants and saves production costs.

Although the content of the present invention has been disclosed in the above embodiments, it is not intended to limit the content of the present invention. Anyone who is familiar with the art can make various changes and modifications without departing from the spirit and scope of the content of the present invention. Therefore, The scope of protection of the content of the present invention shall be subject to those defined by the attached patent application scope and its equivalent scheme.

102: first storage tank

103: Electrolyzer

1030: Recycling copper metal unit

103A: anode chamber

103B: Cathode chamber

104: Gas-liquid reactor

105: second storage tank

106: Chlorine Absorber

107: Wet etching machine

108: Acid etching waste liquid supply source

109: Specific gravity controller

110: Etchant storage tank

31G: Gas outlet

31L: Liquid outlet

41L: first liquid inlet

41LE: The first liquid outlet

41G: gas inlet

41GL: Gas outlet

42L: second liquid inlet

42LE: second liquid outlet

500: Regenerated acid etching waste liquid system

51L: entrance

51LE: Exit

61G: Chlorine gas inlet

Claims (10)

A method for regenerating acid etching waste liquid, comprising: (i) providing an etching solution to be processed, including copper ions, cuprous ions, and chloride ions; (ii) transporting the etching solution to be processed to an electrolytic cell for electrolytic reaction, to Obtain an electrolytic regenerating solution, wherein an anode of the electrolytic cell converts cuprous ions into copper ions and chlorine ions into chlorine gas, and a cathode of the electrolytic cell converts copper ions into copper metal. The concentration of cuprous ions is lower than the concentration of cuprous ions in the etching solution to be processed; (iii) the chlorine gas obtained from the anode and the electrolytic regeneration solution are respectively sent to a gas-liquid reactor for reaction, so that the electrolytic regeneration solution The cuprous ions in the copper ions are converted to copper ions to obtain a regenerated acid etching solution; and (iv) the regenerated acid etching solution is transferred to a wet etching machine for use. The method according to claim 1, wherein step (iii) further comprises sending unreacted chlorine gas to a chlorine gas absorber to be absorbed. The method according to claim 1, wherein before step (iv), an etching additive is added to the regenerated acid etching solution. The method according to claim 1, wherein the etching solution to be processed contains CuCl ₂ . The method according to claim 1, wherein the etching solution to be processed contains HCl. A system for regenerating acid etching waste liquid, comprising: a first storage tank configured to store an etching solution to be processed; an electrolytic tank configured to receive the etching solution to be processed, and perform an electrolytic reaction on the etching solution to be processed , Wherein the electrolytic tank includes a first gas outlet and a liquid outlet; a gas-liquid reactor configured to process the etching solution to be processed by the electrolysis reaction to obtain a regenerated acid etching solution, and the gas-liquid reactor includes: A first liquid inlet connected to the liquid outlet of the electrolytic cell to receive the etching solution to be treated after the electrolysis reaction; a second liquid inlet connected to an acid etching waste liquid supply source; a gas inlet connected to the electrolysis The first gas outlet of the tank; and a first liquid outlet configured to output the regenerated acid etching solution. The system according to claim 6, further comprising a second storage tank, an inlet of the second storage tank is connected to the liquid outlet of the electrolysis tank to receive the etching solution to be treated after the electrolysis reaction, and the second storage tank An outlet of the two storage tanks is connected to the first liquid inlet of the gas-liquid reactor. The system according to claim 7, further comprising: a chlorine gas absorber configured to absorb chlorine gas, the chlorine gas absorber comprising: A chlorine gas inlet is connected to the second gas outlet of the electrolytic cell. The system according to claim 8, wherein the gas-liquid reactor further comprises: a second gas outlet connected to the chlorine inlet of the chlorine absorber; and a second liquid outlet connected to the first storage tank. The system according to claim 6, wherein the first liquid outlet of the gas-liquid reactor is connected to a wet etching machine.

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