Method and device for progressively electrolyzing and recycling acid etching waste liquid

Abstract

The invention discloses a method and a device for progressively electrolyzing and recycling acid etching waste liquid, which adopt at least one electrolytic bath A, and an anode bath area and a cathode bath area are arranged in the electrolytic bath A; an electrolysis anode and an electrolysis cathode are respectively arranged during electrolysis operation; catholyte of the electrolytic bath A contains acidic etching waste liquid; at least one electrolytic bath B is adopted and is internally divided into an anode bath area and a cathode bath area; an electrolytic anode and an electrolytic cathode are respectively arranged during the electrolysis operation, so that the electrochemical reaction that copper ions are reduced into metal copper is generated on the electrolytic cathode of the electrolytic bath B; and the catholyte of the electrolytic bath B comprises the catholyte of the electrolytic bath A subjected to electrolysis treatment or a mixed solution of the catholyte and the acidic etching waste liquid. According to the method disclosed by the invention, circuit board production enterprises can safely recover copper from the acidic etching waste liquid, meanwhile, the back corrosion of electrically separated metal copper on the cathode in the electrolytic copper taking process is reduced, new impurities are prevented from being introduced, and the electrolysis energy consumption is reduced.

Description

A method and device for recycling acidic etching waste liquid by progressive electrolysis Technical Field

[0001] The invention belongs to the technical field of recycling and reusing waste etching liquid of a circuit board, and particularly relates to a method and a device for recycling waste acid etching liquid by progressive electrolysis. Background Art

[0002] In the current production process of printed circuit boards, an acidic etching process using a spray process is a key step. This process removes unwanted copper from the copper-clad substrate through a chemical reaction using an acidic etching solution, thereby forming the desired circuit pattern. Current acidic etching solutions primarily use copper chloride and / or ferric chloride as copper etchants. The main components of existing acidic etching solutions in the industry are copper chloride and hydrochloric acid, and may also contain ferric chloride, ammonium chloride, and / or sodium chloride.

[0003] During the etching process, while metallic copper corrodes, the copper etchant is reduced, losing its etching ability. Specifically, cupric chloride is reduced to cuprous chloride, and / or ferric chloride is reduced to ferrous chloride. To maintain etching production, the etching solution must be supplemented with an oxidizing agent, hydrochloric acid, and / or ferric chloride, along with optional additives. This allows the cuprous chloride and ferrous chloride to be oxidized and regenerated into cupric chloride and ferric chloride, which continue to participate in etching. This can cause the etching solution volume to increase and overflow the tank. Additives in etching solutions are typically used to improve etching performance. One type of additive is designed to enhance the common ion effect of chloride ions. Common examples include ferric chloride, ferric dichloride, ammonium chloride, sodium chloride, and sodium chlorate. Ferric chloride is both a copper etchant and an additive that enhances the common ion effect. Because acidic etching solutions containing ferric chloride copper etchant effectively reduce the pool effect during etching, the industry prefers acidic iron-containing etching solutions in pursuit of high-quality and efficient products.

[0004] The industry refers to etching solution that overflows from the tank as etching waste liquid, the solution within the etching tank as etching working solution, and the solution containing hydrochloric acid and / or oxidants and / or additives added during the etching process as etching sub-liquid. Most acidic etching waste liquids have a copper ion concentration of 70 to 200 g / L. Iron-containing acidic etching waste liquids, including ferric chloride and ferrous chloride, can contain up to 200 g / L of total iron.

[0005] Circuit board manufacturing plants generate large quantities of acidic etching wastewater daily during the etching process. Prior art methods utilize electrolytic cells to directly electrolyze and extract copper from the acidic etching wastewater. These methods employ an electrolytic cell with separate anode and cathode compartments, with the acidic etching wastewater added directly to the anode compartment for electrolysis. However, this approach results in significant chloride ion losses in the etching wastewater and requires the addition of a large amount of oxidant to the etching solution to maintain the etching process, resulting in an increase in the amount of etching wastewater.

[0006] Redirecting the acidic etching wastewater to the cathode tank for electrolysis can effectively reduce or even eliminate the need to add oxidants to the etching solution during the recycling process, thus resolving the wastewater wastewater increase problem. However, the acidic etching wastewater still contains a large amount of copper-etching agents, which are highly corrosive to metallic copper. Iron-containing acidic etching wastewater is particularly aggressive towards metallic copper. Therefore, when the acidic etching wastewater is added to the cathode tank, the introduced copper-etching agents will corrode the copper deposited at the cathode. This not only consumes a large amount of electrical energy but also causes the deposited copper layer to become loose and rough due to corrosion. When the copper blocks are removed from the cathode, they easily break and fall into the electrolytic cell, impacting production. To overcome these shortcomings of the electrolytic recycling process, the industry has adopted the practice of adding copper plating brighteners to the cathode electrolyte to improve the smoothness and density of the deposited copper blocks. However, this method actually introduces new impurities into the etching wastewater, making it impossible for the electrolytic recycling process to achieve 100% recycling of the etching wastewater.

[0007] Therefore, circuit board manufacturers in the industry are looking forward to the introduction of a new process that can solve the shortcomings of the current electrolytic recovery and recycling process of acid etching waste liquid.

[0008] Summary of the Invention

[0009] A first object of the present invention is to provide a method for progressively electrolyzing and recycling acidic etching waste liquid of circuit boards, so that circuit board manufacturers can safely recover copper from the acidic etching waste liquid while reducing the back etching of the electrolytically deposited metallic copper on the cathode during the electrolytic copper extraction process and avoiding the introduction of new impurities, thereby reducing electrolysis energy consumption and facilitating the re-allocation of the waste liquid after copper recovery into a regenerated etching sub-liquid to increase the waste liquid reuse rate. In this way, production costs can be significantly reduced while also reducing environmental pollution.

[0010] The second object of the present invention is to provide a device for recycling circuit board acid etching waste liquid by progressive electrolysis.

[0011] The first object of the present invention can be achieved by adopting the following technical solutions:

[0012] A method for recycling circuit board acid etching waste liquid by progressive electrolysis mainly comprises the following steps:

[0013] Step 1: using at least one electrolytic cell A, wherein the electrolytic cell A is separated into an anode cell area and a cathode cell area by an electrolytic cell separator; during electrolysis operation, the anode cell area and the cathode cell area of ​​the electrolytic cell A are respectively provided with an electrolytic anode and an electrolytic cathode, and electrolysis operation is performed on the anolyte and catholyte of the electrolytic cell A respectively; the catholyte of the electrolytic cell A contains acidic etching waste liquid;

[0014] Step 2: Using at least one electrolytic cell B for progressive electrolysis to extract copper, the electrolytic cell B is divided into an anode cell area and a cathode cell area; during the electrolysis operation, the anode cell area and the cathode cell area of ​​the electrolytic cell B are respectively provided with an electrolytic anode and an electrolytic cathode, and electrolysis operations are performed on the anode electrolyte and the cathode electrolyte of the electrolytic cell B respectively, so that an electrochemical reaction occurs at the electrolytic cathode of the electrolytic cell B in which copper ions are reduced to metallic copper; the cathode electrolyte of the electrolytic cell B comprises the electrolytically treated cathode electrolyte of the electrolytic cell A or a mixture of the cathode electrolyte and acidic etching waste liquid;

[0015] Step 3: When the amount of metallic copper deposited on the electrolytic cathode of the electrolytic cell B due to the electrochemical reaction reaches a preset electrolysis target amount, the electrolytic cathode of the electrolytic cell B is removed from the electrolytic cell B.

[0016] The anolyte of electrolytic cell A comprises at least one of an etching working solution, an etching waste solution, and an electrolytically treated catholyte of electrolytic cell B. The anolyte of electrolytic cell B comprises at least one of an electrolytically treated catholyte of electrolytic cell B, an etching working solution, and an etching waste solution.

[0017] During the electrolysis process of the present invention, chlorine gas is electrochemically deposited at the anodes of electrolytic cell A and electrolytic cell B, and / or low-valent metal ions in the electrolyte are oxidized to high-valent ions. Metal ion reduction occurs primarily at the cathode of electrolytic cell A, reducing the concentration of the copper-electrolyte in its cathode electrolyte. Meanwhile, copper ions are electrochemically reduced to metallic copper at the cathode of electrolytic cell B. To maintain the electrolysis process, the corresponding electrolytic solution is continuously added to each cell during operation.

[0018] The cathode electrolyte of electrolytic cell B after electrolytic treatment can be oxidized in the anode tank area of ​​electrolytic cell A and / or the anode tank area of ​​electrolytic cell B, and / or oxidized using the chlorine gas electrolyzed by the electrolytic cell, and then recycled as a regenerated etching sub-liquid directly or after preparation. The above preparation can also be changed to pre-preparing at least one of the anode electrolyte and cathode electrolyte of electrolytic cell A and the anode electrolyte and cathode electrolyte of electrolytic cell B, which can also achieve the purpose of the present invention.

[0019] The electrolytic cell separator of the electrolytic cell A can effectively cause the anolyte to undergo an oxidation reaction and the cathode electrolyte to undergo a reduction reaction to reduce the valence of high-valent metal ions. Specifically, at least one of an anion exchange membrane, a bipolar membrane, and a reverse osmosis membrane is selected.

[0020] The electrolytic cell B may be an electrolytic cell having an anode cell region and a cathode cell region in any structural form. When the anode cell region and the cathode cell region of the electrolytic cell B are separated by a cell separator, the cell separator of the electrolytic cell B may be at least one of an anion exchange membrane, a bipolar membrane, and a reverse osmosis membrane.

[0021] The present invention can be improved as follows: the redox potential of the cathode electrolyte in the cathode tank area of ​​the electrolytic cell A is detected to monitor the electrolysis process and the concentration of high-valent metal ions in the solution, so that the cathode electrolyte of the electrolytic cell A mainly undergoes a reaction to reduce the concentration of the copper etching agent, and no or less electrochemical reaction of electrolytic copper occurs.

[0022] The present invention can be further improved as follows: the output current of the electrolytic power supply of electrolytic cell A is adjusted or started and shut down according to the redox potential value of the cathode electrolyte in the cathode tank area of ​​electrolytic cell A according to process requirements, and / or a solution containing acidic etching waste liquid is added to the cathode tank area of ​​electrolytic cell A to maintain the concentration of the copper corrosive agent in its cathode electrolyte so that less or no metallic copper is electrolytically deposited on the electrolytic cathode, and the copper corrosive agent CuCl2, or CuCl2 and FeCl3 in the cathode electrolyte of electrolytic cell A is mainly subjected to electrochemical reduction reaction to reduce the concentration or even eliminate its copper corrosive ability.

[0023] Preferably, during the electrolysis process, the redox potential of the cathode electrolyte of electrolytic cell A is controlled within a range of 200 to 580 mV, i.e., the redox potential (ORP) value of the external wastewater is controlled within a range of 200 to 580 mV. More preferably, the redox potential of the cathode electrolyte of electrolytic cell A is controlled within a range of 300 to 499 mV. To achieve a better progressive copper removal effect by eliminating the copper-corroding agent, the ORP value of the cathode electrolyte of electrolytic cell A is controlled within a range of 350 to 470 mV.

[0024] The present invention can be improved as follows: at least one electrolytic cell C is added and arranged after electrolytic cell B, wherein the electrolytic cell C is divided into an anode cell area and a cathode cell area; during electrolysis operation, an electrolysis anode and an electrolysis cathode are respectively provided in the anode cell area and the cathode cell area of ​​the electrolytic cell C, and electrolysis operation is performed on the anolyte and the catholyte respectively; the anolyte of the electrolytic cell C contains at least one of an acidic etching working solution, the catholyte of the electrolytic cell B after electrolysis treatment, and the catholyte of the electrolytic cell C after electrolysis treatment, or further contains etching waste liquid; the catholyte of the electrolytic cell C contains the catholyte of the electrolytic cell B after electrolysis treatment, or further contains the catholyte of the electrolytic cell A and / or etching waste liquid. At this time, the anolyte of the electrolytic cell A contains at least one of the catholyte of the electrolytic cell B after electrolysis treatment, the catholyte of the electrolytic cell C after electrolysis treatment, the etching working fluid, and the etching waste liquid; the anolyte of the electrolytic cell B contains at least one of the catholyte of the electrolytic cell B after electrolysis treatment, the catholyte of the electrolytic cell C after electrolysis treatment, the etching working fluid, and the etching waste liquid.

[0025] During the electrolysis process using electrolytic cell C, an electrochemical reaction occurs at the electrolytic cathode of electrolytic cell C, in which copper ions are reduced to metallic copper, and then copper is further electrolytically extracted in a progressive manner. The catholyte of electrolytic cell B and / or the catholyte of electrolytic cell C, which have undergone electrolytic treatment, can be oxidized and / or oxidized using chlorine gas in one or more of the anode tank area of ​​electrolytic cell A, the anode tank area of ​​electrolytic cell B, and the anode tank area of ​​electrolytic cell C, and then directly or after preparation, recycled as a regenerated etching sub-liquid. The above preparation can also be changed to pre-preparing at least one of the anode electrolyte and cathode electrolyte of electrolytic cell A, the anode electrolyte and cathode electrolyte of electrolytic cell B, and the anode electrolyte and cathode electrolyte of electrolytic cell C, which can also achieve the purpose of the present invention.

[0026] The electrolytic cell C may be an electrolytic cell having an anode cell area and a cathode cell area in any structural form. When the electrolytic cell C is separated into cell areas by a cell separator, the cell separator may be at least one of an anion exchange membrane, a bipolar membrane, and a reverse osmosis membrane.

[0027] During the electrolysis process in the progressive electrolysis apparatus of the present invention, since the anolyte of electrolytic cell A, the anolyte of electrolytic cell B, and the anolyte of electrolytic cell C all contain chloride ions, an electrochemical reaction occurs at the electrolytic anodes of electrolytic cell A, electrolytic cell B, and electrolytic cell C, where the chloride ions are oxidized to chlorine gas. The generated chlorine gas has strong oxidizing properties and can oxidize low-valent metal ions in the anolyte of electrolytic cell A, electrolytic cell B, and electrolytic cell C, thereby achieving oxidative regeneration of the copper corroder. Simultaneously, a reduction electrochemical reaction occurs at the electrolytic cathode of electrolytic cell A, causing the copper corroder in its catholyte to undergo a reduction reaction to form cuprous chloride and / or ferrous chloride, thereby depleting its copper corroding ability. Subsequently, the catholyte from electrolytic cell A, which has lost or reduced its copper-electrolyzing ability, is added to the cathode compartment of electrolytic cell B as part or all of its catholyte for electrolysis, causing copper metal to be electrolytically deposited on the cathode of electrolytic cell B. When electrolytic cell C is added, the catholyte from electrolytic cell B, which has undergone electrolysis, is added to the cathode compartment of electrolytic cell C as part or all of its catholyte for further progressive electrolysis and copper extraction at the next level.

[0028] The present invention utilizes a progressive electrolytic copper deposition method, allowing the copper deposited on the cathodes of electrolytic cells B and C to form in an environment with a low copper etchant concentration. This effectively reduces the chemical reaction of the cathode electrolyte on the deposited copper during the electrolytic recovery process, resulting in a smoother and denser copper layer. The process of the present invention overcomes the drawback of existing electrolytic recovery of acidic etching waste liquid, which results in a loose copper layer, while also facilitating 100% recycling of the etching waste liquid.

[0029] The electrolytic anode of the present invention is made of a material whose shape and properties are stable in the electrolyte. Specifically, at least one of a material having a surface of gold and / or platinum and / or an alloy containing at least one of the above metals, an insoluble anode with a titanium-based coating, and conductive graphite can be used, preferably an insoluble anode with a titanium-based coating. The electrolytic cathode of electrolytic cell A is made of gold and / or platinum and / or titanium and / or an alloy containing at least one of the above metals and / or conductive graphite, preferably titanium. The electrolytic cathodes of electrolytic cells B and C can be made of gold and / or platinum and / or titanium and / or copper and / or an alloy containing at least one of the above metals and / or stainless steel, preferably copper.

[0030] The main chemical reactions occurring in each cell area of ​​electrolytic cell A, electrolytic cell B, and electrolytic cell C are as follows:

[0031] (1) Each anode tank area

[0032] 2CuCl+Cl2→2CuCl2;

[0033] 2FeCl2+Cl2→2FeCl3 (when the etching solution contains iron ions).

[0034] (2) Cathode tank area of ​​electrolytic cell A

[0035] (When the etching solution contains iron ions).

[0036] (3) Cathode tank area of ​​electrolytic cell B and cathode tank area of ​​electrolytic cell C

[0037] The present invention can be improved by controlling the copper ion concentration of the electrolytic cathode of electrolytic cell B and the catholyte of electrolytic cell C to be no less than 5 g / L. The inventors have found through multiple experiments that maintaining the copper ion concentration of the catholyte at no less than 5 g / L can prevent a high incidence of hydrogen evolution side reactions.

[0038] The present invention can be improved as follows: the cathode electrolyte from the end electrolytic tank B after electrolysis or the cathode electrolyte from the end electrolytic tank C after electrolysis is subjected to oxidation regeneration treatment according to process requirements and / or hydrochloric acid and additives are added to re-prepare the regenerated etching sub-liquid, so that the concentration of cuprous ions and / or ferrous ions in the regenerated etching sub-liquid meets the minimum process requirements and does not affect the etching performance when it is returned to the etching production line for use.

[0039] The present invention can be improved as follows: a cathode cloth filter bag is used to cover the electrolytic cathode of at least one electrolytic cell at the end to collect the sponge copper produced during the copper electrolysis process.

[0040] The present invention can be improved as follows: at least one parameter value of the electrolyte in the present invention is detected, and the data measured on site is used as a basis to control the output current of the electrolytic power supply of electrolytic cell A and / or the electrolytic power supply of electrolytic cell B and / or the electrolytic power supply of electrolytic cell C and / or to control the addition of various materials. The chlorine gas generated in the anode tank area of ​​electrolytic cell A and / or the anode tank area of ​​electrolytic cell B and / or the anode tank area of ​​electrolytic cell C can be safely controlled and more completely utilized, and / or the solution reaction can be carried out according to process requirements. The parameter values ​​detected include, but are not limited to, any one or more of the following: acidity, specific gravity, redox potential, photoelectric colorimetric value, liquid level, temperature, flow rate, and harmful gas concentration.

[0041] The present invention can be improved by circulating and mixing the anolyte of electrolytic cell A and / or the anolyte of electrolytic cell B and / or the anolyte of electrolytic cell C in an electrolytic cell equipped with an electrolytic separator with the etching working solution on the etching production line, thereby enabling online replenishment of the etching working solution with copper etching agent. Specifically, the low-valent copper ions or low-valent iron ions in the etching working solution can be used to generate copper chloride or ferric chloride, a regenerated copper etching agent, through an electrochemical reaction at the electrolytic cell anode, and continue to participate in the etching reaction. The present invention connects the etching cell to the anode cell area of ​​at least one electrolytic cell via a pipeline, allowing the etching working solution to circulate within each anode cell area. At least one of the electrolytically oxidized anolyte of electrolytic cell A, the anolyte of electrolytic cell B, and the anolyte of electrolytic cell C is directly returned to the etching cell for use as the etching working solution for newly generated copper etching agent. This effectively reduces or even eliminates the need for adding oxidants from outside the etching system in traditional production processes, thereby helping to reduce production costs.

[0042] The present invention can be further improved by providing a circulating mixing and exchange tank for the etching solution and the anolyte between the etching production line and the anode tank of at least one electrolytic cell, and controlling the redox potential of the mixed solution to be higher than the redox potential of the etching solution. Preferably, a circulating mixing and exchange tank with a larger total volume is used to efficiently utilize the electrolytic equipment to pre-prepare more copper etching agent as a response to the rapid addition during the etching reaction.

[0043] The present invention can be further improved as follows: the temperature of the solution to be fed into the etching production line is controlled to avoid the influence of the etching rate stability due to the temperature change of the etching working solution when the mixed solution is fed into the etching production line.

[0044] The present invention can be further improved by removing oil and solid impurities from the etching solution before it enters the electrolytic cell.

[0045] The present invention can be further improved as follows: when the etching waste liquid contains iron ions, the etching waste liquid is added to the cathode tank area of ​​electrolytic cell B and / or electrolytic cell C according to the process requirements. Preferably, the feeding port is close to the separator, and the Fe in the etching waste liquid is used to 3+ The ions react with the CuCl copper mud, causing the insoluble cuprous chloride mud to react to form cupric chloride, thus avoiding the clogging of the separator and affecting the electrolysis operation.

[0046] The second object of the present invention can be achieved by adopting the following technical solutions:

[0047] A device for recycling circuit board acid etching waste liquid by progressive electrolysis, which mainly includes:

[0048] At least one electrolytic cell A and at least one electrolytic cell B are used. The interior of the electrolytic cell A is separated by an electrolytic cell separator into an anode cell area and a cathode cell area, and the interior of the electrolytic cell B is divided into an anode cell area and a cathode cell area. A redox potentiometer is installed in the cathode cell area of ​​the electrolytic cell A. The cathode cell area of ​​the electrolytic cell A and the cathode cell area of ​​the electrolytic cell B are connected by a liquid flow pipeline. The solution that has undergone electrolysis reaction in the cathode cell area of ​​the electrolytic cell A is added to the cathode cell area of ​​the electrolytic cell B for progressive electrolysis to extract copper. The anode cell area of ​​the electrolytic cell A and the cathode cell area of ​​the electrolytic cell A are respectively provided with an electrolysis anode and an electrolysis cathode, and the electrolysis anode and the electrolysis cathode are respectively connected to the positive electrode and the negative electrode of the electrolysis power supply of the electrolytic cell A. The anode cell area of ​​the electrolytic cell B and the cathode cell area of ​​the electrolytic cell B are respectively provided with an electrolysis anode and an electrolysis cathode of the electrolytic cell B, and the electrolysis anode and the electrolysis cathode are respectively connected to the positive electrode and the negative electrode of the electrolysis power supply of the electrolytic cell B.

[0049] During the electrolysis process, the anode tank area of ​​electrolytic cell A and the cathode tank area of ​​electrolytic cell A are respectively filled with anolyte and catholyte, and the anode tank area of ​​electrolytic cell B and the cathode tank area of ​​electrolytic cell B are respectively filled with anolyte and catholyte; the anolyte of electrolytic cell A contains at least one of an etching working solution, an etching waste solution, and the catholyte of electrolytic cell B after electrolytic treatment, and the catholyte of electrolytic cell A contains acidic etching waste solution; the anolyte of electrolytic cell B contains at least one of an electrolytically treated catholyte of electrolytic cell B, an etching working solution, and an etching waste solution, and the catholyte of electrolytic cell B contains the electrolytically treated catholyte of electrolytic cell A or a mixture thereof with acidic etching waste solution.

[0050] The electrolytic cell separator of the electrolytic cell A is selected from at least one of an anion exchange membrane, a bipolar membrane, and a reverse osmosis membrane.

[0051] The electrolytic cell B may be an electrolytic cell having an anode cell region and a cathode cell region in any structure, specifically, a structure with or without an electrolytic separator. When the anode cell region and the cathode cell region of the electrolytic cell B are separated by an electrolytic cell separator, the electrolytic cell separator of the electrolytic cell B is selected from at least one of an anion exchange membrane, a bipolar membrane, and a reverse osmosis membrane.

[0052] The present invention can be improved as follows: the output current of electrolytic power supply A is adjusted or shut down according to the process requirements based on the value measured by the redox potential meter in the cathode tank area of ​​electrolytic cell A, and / or a solution containing acidic etching waste liquid is controlled and added to the cathode tank area of ​​electrolytic cell A.

[0053] The present invention can be improved as follows: at least one electrolytic cell C is added and arranged after the electrolytic cell B, wherein the electrolytic cell C is divided into an anode cell area and a cathode cell area; the cathode cell area of ​​the electrolytic cell B is connected to the cathode cell area of ​​the electrolytic cell C through a liquid flow pipeline, and the solution treated by electrolysis in the cathode cell area of ​​the electrolytic cell B is added to the cathode cell area of ​​the electrolytic cell C; the anode cell area of ​​the electrolytic cell C and the cathode cell area of ​​the electrolytic cell C are respectively provided with an electrolytic anode and an electrolytic cathode, and the electrolytic anode and the electrolytic cathode are respectively connected to the positive electrode and the negative electrode of the electrolytic power supply C; the electrolysis process In the embodiment, the anode tank area and cathode tank area of ​​electrolytic cell C are respectively filled with anolyte and catholyte; the anolyte of electrolytic cell C comprises at least one of an etching working solution, the catholyte of electrolytic cell B after electrolysis treatment, and the catholyte of electrolytic cell C after electrolysis treatment, or further comprises etching waste liquid on this basis; the catholyte of electrolytic cell C comprises the catholyte of electrolytic cell B after electrolysis treatment, or further comprises the catholyte of electrolytic cell A and / or etching waste liquid on this basis. In this case, the anolyte of electrolytic cell A comprises at least one of the catholyte of electrolytic cell B after electrolysis treatment, the catholyte of electrolytic cell C after electrolysis treatment, etching working solution, and etching waste liquid; the anolyte of electrolytic cell B comprises at least one of the catholyte B of electrolytic cell B after electrolysis treatment, the catholyte of electrolytic cell C after electrolysis treatment, etching working solution, and etching waste liquid.

[0054] The electrolytic cell C may be an electrolytic cell having an anode cell region and a cathode cell region in any structure, specifically, a structure with or without an electrolytic separator. When the anode cell region and the cathode cell region of the electrolytic cell C are separated by an electrolytic cell separator, the electrolytic cell separator of the electrolytic cell C is selected from at least one of an anion exchange membrane, a bipolar membrane, and a reverse osmosis membrane.

[0055] The electrolytic anode of the present invention is made of a material whose shape and properties are stable in the electrolyte. Specifically, at least one of a material having a surface of gold and / or platinum and / or an alloy containing at least one of the above metals, an insoluble anode with a titanium-based coating, and conductive graphite can be used, preferably an insoluble anode with a titanium-based coating. The electrolytic cathode of electrolytic cell A is made of gold and / or platinum and / or titanium and / or an alloy containing at least one of the above metals and / or conductive graphite, preferably titanium. The electrolytic cathodes of electrolytic cells B and C can be made of gold and / or platinum and / or titanium and / or copper and / or an alloy containing at least one of the above metals and / or stainless steel, preferably copper.

[0056] The present invention can be improved as follows: a cathode cloth filter bag is used to cover the electrolytic cathode of at least one electrolytic cell at the end to collect the sponge copper produced during the copper electrolysis process.

[0057] The present invention can be improved as follows: additional sensors and an automatic detection and feeding controller are provided, and at least one sensor is used to detect at least one of the anolyte and cathode electrolyte of electrolytic cell A, the anolyte and cathode electrolyte of electrolytic cell B, and the anolyte and cathode electrolyte of electrolytic cell C, and the data measured on site are transmitted to the automatic detection and feeding controller for processing to control the output current of at least one electrolytic power supply and / or the addition of various materials.

[0058] Preferably, the sensor is at least one selected from a pH meter, a hydrometer, a redox potentiometer, a photoelectric colorimeter, a liquid level meter, a thermometer, a flow meter, and a chlorine gas detector.

[0059] The present invention can be improved as follows: a circulating mixing exchange tank is added, the anode tank area of ​​electrolytic cell A and / or the anode tank area of ​​electrolytic cell B and / or the anode tank area of ​​electrolytic cell C in the electrolytic cell provided with an electrolytic separator are connected to the circulating mixing exchange tank by a circulating pipeline, and the circulating mixing exchange tank is connected to the etching production line by a circulating pipeline, so that the anolyte and the etching working solution are mixed in the circulating mixing exchange tank, and the etching working solution on the etching production line can be replenished with copper etching agent in real time online.

[0060] Preferably, a larger volume circulating mixing exchange tank is used to control the redox potential of the solution in the tank to be higher than that of the etching working solution, so that the copper etching agent concentration in the tank solution is much higher than that of the etching working solution to efficiently utilize the electrolytic equipment.

[0061] The present invention can be improved as follows: a hot and cold temperature exchanger is added to adjust and control the temperature of the solution that is about to enter the etching production line.

[0062] The present invention can be improved as follows: a temporary storage tank is added to temporarily store various solutions and / or used as a chemical reaction preparation tank for the solutions.

[0063] The present invention can be improved as follows: an additional tail gas treatment tank is provided to treat the tail gas released from each electrolytic cell and each temporary storage tank during operation.

[0064] The present invention can be improved as follows: an agitator is added, and its structure includes an impeller agitator and a circulating liquid flow pump pipe agitator, which are used to stir and mix the solutions in the electrolytic tank and the temporary storage tank.

[0065] The present invention can be improved as follows: an overflow buffer tank can be added to solve the problem of solution flow with different liquid levels between tanks.

[0066] The present invention can be improved as follows: a sealed tank cover with an exhaust hole and a feeding port is added to the electrolytic tank to collect the electrolyzed chlorine or oxygen for safe production utilization.

[0067] The present invention can be improved as follows: a movable tank cover is added to the cathode tank area of ​​the electrolytic tank to facilitate the collection and treatment of acidic waste gas and the extraction of cathode to recover metallic copper.

[0068] The present invention can be improved as follows: a gas-liquid mixer is added, and its structure can be a vacuum jet gas-liquid mixer or a spray gas-liquid mixer for mixing gas and liquid.

[0069] The present invention can be improved as follows: a filter is added to separate the solid and liquid of the treated solution or to remove impurities from the organic matter.

[0070] The present invention can be improved as follows: add a feeding pipe for etching waste liquid in the cathode tank area of ​​electrolytic cell B and / or electrolytic cell C. Preferably, the feeding pipe is installed close to the separator so that the Fe in the iron-containing etching waste liquid is 3+ The ions react with the cuprous chloride adhering to the separator to form cupric chloride which dissolves in the cathode electrolyte, thus preventing the separator from clogging. The addition can be controlled according to the time interval or cell pressure.

[0071] Compared with the prior art, the present invention has the following beneficial effects:

[0072] 1. The present invention solves the process problem of loose and easily broken copper blocks in the existing electrolytic recovery process of circuit board acid etching waste liquid.

[0073] 2. The present invention can achieve 100% recycling of the acidic etching waste liquid of the circuit board by electrolysis, thereby significantly reducing production costs and reducing environmental pollution.

[0074] 3. In the process of the present invention, no new substances are added during the entire recycling process, and the recycled etching liquid has no effect on the quality and efficiency of the etching production.

[0075] 4. The process of the present invention can realize that in recycling production, there is no need to add external oxidants from the acid etching system, so that the production cost is reduced.

[0076] 5. When using an acidic ferrous etching solution, the process of the present invention can give full play to the advantages of the acidic ferrous etching process, thereby improving both etching efficiency and etching quality. Description of the drawings:

[0077] The process of the present invention is further described below with reference to the accompanying drawings.

[0078] FIG1 is a device for recycling acidic etching waste liquid of circuit boards by progressive electrolysis according to Example 1 of the present invention;

[0079] FIG2 is a device for recycling acidic etching waste liquid of circuit boards by progressive electrolysis according to Example 2 of the present invention;

[0080] Figure 2.1 is an enlarged view of 2-E in Figure 2;

[0081] Figure 2.2 is an enlarged view of 2-F in Figure 2;

[0082] Figure 2.3 is an enlarged view of 2-G in Figure 2;

[0083] Figure 2.4 is an enlarged view of 2-H in Figure 2;

[0084] FIG3 is a device for recycling acidic etching waste liquid of circuit boards by progressive electrolysis according to Example 3 of the present invention;

[0085] Figure 3.1 is an enlarged view of 3-E in Figure 3;

[0086] Figure 3.2 is an enlarged view of 3-F in Figure 3;

[0087] Figure 3.3 is an enlarged view of 3-G in Figure 3;

[0088] Figure 3.4 is an enlarged view of 3-H in Figure 3;

[0089] Figure 3.5 is an enlarged view of 3-K of Figure 3;

[0090] FIG4 is a device for recycling acidic etching waste liquid of circuit boards by progressive electrolysis according to Example 4 of the present invention;

[0091] Figure 4.1 is an enlarged view of 4-E in Figure 4;

[0092] Figure 4.2 is an enlarged view of 4-F in Figure 4;

[0093] Figure 4.3 is an enlarged view of 4-G in Figure 4;

[0094] Figure 4.4 is an enlarged view of 4-H of Figure 4;

[0095] FIG5 is a device for recycling acidic etching waste liquid of a circuit board by progressive electrolysis according to Example 8 of the present invention;

[0096] Figure 5.1 is an enlarged view of 5-E in Figure 5;

[0097] Figure 5.2 is an enlarged view of 5-F in Figure 5;

[0098] Figure 5.3 is an enlarged view of 5-G in Figure 5;

[0099] Figure 5.4 is an enlarged view of 5-H in Figure 5;

[0100] Figure 5.5 is an enlarged view of 5-K of Figure 5;

[0101] FIG6 is a photograph of metallic copper recovered using the scheme of the present invention;

[0102] FIG7 is a photograph of metallic copper obtained by directly electrolyzing the etching waste liquid into the cathode tank area using the prior art. 1-electrolytic cell A, 2-electrolytic cell B, 3-electrolytic cell A separator, 4-electrolytic cell B separator, 5-electrolytic power supply of electrolytic cell A, 6-electrolytic power supply of electrolytic cell B, 7-oxidation-reduction potential controller of cathode tank area of ​​electrolytic cell A, 8-electrolytic cell C, 9-electrolytic cell C separator, 10-electrolytic power supply of electrolytic cell C, 23-50-temporary storage tank, 51-70-overflow buffer tank, 71-75-vacuum jet gas-liquid mixer, 76-80-spray gas-liquid mixer, 81-90-circulating liquid flow stirring mixer, 91-solid feeder, 92-95-impeller agitator, 96-water-oil separator, 97-100-solid-liquid separation filter, 101-130-sensor, 131-automatic detection and feeding controller, 132-valve, 133-pump, 134-cathode tank area etching waste liquid feeding Tube, 251-Acidic iron-containing etching waste liquid, 252-Regenerated etching sub-liquid, 253-Electrolytic recovery of metallic copper, 256-Cathode electrolyte overflow from electrolytic cell B that has been treated for copper recovery, 257-259-Circuit board etching production line, 260-Oxidation regeneration etching liquid, 261-266-Hot and cold temperature exchangers, 267-Sodium hydroxide solution, 268-Overflow liquid from the cathode tank area of ​​electrolytic cell A, 269-280-Electrolytic cell sealed tank cover with exhaust hole and feeding port, 281-282-Tail gas treatment tank, 283-Hydrochloric acid, 284-Ferric chloride, 285-Ammonium chloride, 286-Sodium chloride, 287-Acidic tail gas, 288-Clean water, 289-293-Movable tank cover, 294-295-Cathode cloth filter bag, 296-Ferrous chloride, 297-Ferric hydroxide, 298-Ferrous hydroxide. DETAILED DESCRIPTION

[0103] The electrolytic cell, temporary storage tank, tail gas treatment tank, overflow buffer tank, vacuum jet gas-liquid mixer, spray-type gas-liquid mixer, agitator, and water-oil separator used in the following examples are all manufactured by Yegao Environmental Protection Equipment Manufacturing Co., Ltd. in Foshan, Guangdong Province. The solid-liquid separation filter, electrolytic cell separator membrane, sensor, PLC controller, valve, pump, and chemical raw materials are all commercially available products. In addition to the above, those skilled in the art may also select other products with similar performance to those listed above, and any of these products can achieve the objectives of the present invention.

[0104] Example 1

[0105] As shown in FIG1 , a basic embodiment 1 of a method and apparatus for progressively electrolyzing and recycling circuit board acidic etching waste liquid is shown. The method includes an electrolytic cell A 1, an electrolytic cell B 2, an oxidation-reduction potential controller 7 for the cathode region of electrolytic cell A, a separator 3 for electrolytic cell A, a separator 4 for electrolytic cell B, an electrolysis power supply 5 for electrolytic cell A, an electrolysis power supply 6 for electrolytic cell B, temporary storage tanks 23 to 28, a vacuum jet gas-liquid mixer 71, sensors 101 to 103, valves 132-1 to 132-7, pumps 133-1 to 133-7, acidic etching waste liquid 251, regenerated etching sub-liquid 252, recovered metallic copper 253, cathode electrolyte 256 overflowing from electrolytic cell B that has been processed for copper recovery, and overflow 268 from the cathode region of electrolytic cell A.

[0106] The separator 3 of the electrolytic cell A is a reverse osmosis membrane, and the separator 4 of the electrolytic cell B is an anion exchange membrane.

[0107] The anode material of the electrolytic cell A is platinum metal, and the cathode material is a conductive graphite plate.

[0108] The anode material of the electrolytic cell B is a titanium-based coated electrode, and the cathode material is stainless steel.

[0109] The sensors 101 and 102 are redox potentiometers, and the sensor 103 is a hydrometer (for measuring the concentration of metal ions in a solution).

[0110] The vacuum jet gas-liquid mixer 71 is used to absorb and guide the chlorine gas electrolyzed and escaped from the anode tank area of ​​electrolytic cell A and electrolytic cell B into the temporary storage tank 28 for oxidation regeneration reaction to prepare the regeneration etching sub-liquid 252.

[0111] A sensor 101 is installed in the anode tank area of ​​electrolytic cell A, which controls pump 133-1 to direct the waste etching liquid to the anode tank area of ​​electrolytic cell A. An oxidation-reduction potential controller 7 is installed in the cathode tank area of ​​electrolytic cell A to control pump 133-2 to direct the acidic waste etching liquid 251 from temporary storage tank 23 to the cathode tank area of ​​electrolytic cell A according to the process. The overflow 268 from the cathode tank area of ​​electrolytic cell A, which has undergone electrolytic treatment, is drained into temporary storage tank 25 for temporary storage, where its copper ion concentration is the same as that of the original waste liquid.

[0112] Electrolytic cell B2 is a progressive copper electrolytic cell. Its function is to oxidize the electrolyte and produce chlorine gas in the anode region of electrolytic cell B, while the cathode region electrolyzes copper. The anode electrolyte of electrolytic cell B is the catholyte 256 overflowing from electrolytic cell B2, which has already been used for copper recovery. This electrolyte undergoes an oxidation reaction in the anode region of electrolytic cell B to produce a regenerated etching sub-liquid 252. A hydrometer sensor 103 installed in the cathode region of electrolytic cell B controls the addition of overflow 268 from the cathode region of electrolytic cell A in the temporary storage tank 25 to the cathode region of electrolytic cell B2 for progressive copper electrolysis.

[0113] Catholyte 256 overflowing from electrolytic cell B2, which has already been used for copper recovery, is partially pumped by pump 133-4 into temporary storage tank 28, where it reacts with chlorine gas to produce a regenerated etching solution. Under the control of ORP meter sensor 104, the cuprous chloride and ferrous chloride in the solution in temporary storage tank 28 undergo an oxidation reaction to produce copper chloride and ferric chloride as copper etching agents. Once the solution meets the regenerated etching solution's standard requirements, it is pumped by pump 133-7 into temporary storage tank 26.

[0114] By adjusting the set values ​​of the redox potentiometers of the sensors 102 and 104 , it is possible to modulate the regenerated etching sub-liquid 252 having a low copper ion concentration that meets the process requirements after oxidation treatment.

[0115] The acidic etching waste liquid of this embodiment mainly contains hydrochloric acid, cupric chloride, ferric chloride, ferrous chloride, sodium chloride, ammonium chloride, and water. The acidity is 1.2 mol / L, the copper ion concentration is 120 g / L, and the total iron ion concentration is 100 g / L. Its oxidation-reduction potential (ORP) value is 610 mV.

[0116] The specific steps of this embodiment are as follows.

[0117] 1. Acidic etching waste liquid 251 is added to the anode tank area and cathode tank area of ​​electrolytic cell A as the initial electrolyte. During the electrolysis operation, the amount of acidic etching waste liquid 251 added to the cathode tank area of ​​electrolytic cell A is controlled to cause the divalent copper ions and trivalent iron ions in the etching waste liquid to undergo an electrochemical reduction reaction. The cathode tank area overflows into the temporary storage tank 25 due to full liquid.

[0118] 2. Add the overflow liquid 268 from the cathode tank area of ​​electrolytic cell A in the temporary storage tank 25 to the cathode tank area of ​​electrolytic cell B, and add the cathode electrolyte 256 overflowed from electrolytic cell B that has been processed for copper recovery in the temporary storage tank 27 to its anode tank area.

[0119] 3. Manually connect electrolysis power supply 5 and electrolysis power supply 6 to allow electrolytic cell A and electrolytic cell B to perform electrolysis. During the electrolysis process, the anode region of electrolytic cell A electrolyzes to produce chlorine. The redox potential controller 7 is set to control the redox potential to 580 mV, monitors the acidic etching waste liquid 251 and feeds it to the cathode region of electrolytic cell A, thereby reducing the copper etching agent concentration in the cathode electrolyte and controlling the absence of electrolytic copper deposition on the electrolytic cathode of electrolytic cell A. The sensor 103 in electrolytic cell B monitors the overflow liquid 268 from the cathode region of electrolytic cell A in the temporary storage tank 25 via the hydrometer, and feeds it to the cathode region of electrolytic cell B via the pump 133-3, thereby controlling the copper ion concentration of the cathode electrolyte in the cathode region of electrolytic cell B in the process. The anodes of electrolytic cell A and electrolytic cell B respectively perform electrochemical oxidation reactions on the acidic etching waste liquid 251 and the catholyte 256 overflowing from electrolytic cell B, which has been processed for copper recovery. Simultaneously, chlorine gas emitted from the anode tanks of electrolytic cells A and B is mixed with gas through ejector 71 to oxidize the solution in temporary storage tank 28 to generate regenerated etching sub-liquid 252. The catholyte in electrolytic cell A undergoes a reduction reaction to eliminate the copper-corroding agent, while the cathode of electrolytic cell B electrolytically deposits metallic copper 253. The anode of electrolytic cell B is used to oxidize the catholyte 256 overflowing from electrolytic cell B, which has been processed for copper recovery, to prepare the regenerated etching sub-liquid.

[0120] 4. The parameter values ​​of the regenerated etching liquid are acidity 4.0M / L, copper ion concentration 60g / L, iron ion concentration 100g / L, and ORP value 650mv.

[0121] The above is a process for recycling the acidic etching waste liquid of the circuit board by progressive electrolysis, which can be achieved by using the device in Figure 1 and following the above process steps.

[0122] Example 2

[0123] As shown in FIG2, a method and apparatus for recycling acidic etching waste liquid of circuit boards by progressive electrolysis is shown in Example 2, which includes an electrolytic cell A1, two electrolytic cells B 2-1 and 2-2, cathode area redox potential controller 7 of electrolytic cell A, separator 3 of electrolytic cell A, separators 4-1 and 4-2 of electrolytic cell B, electrolytic power supply 5 of electrolytic cell A, electrolytic power supplies 6-1 and 6-2 of electrolytic cell B, temporary storage tanks 23-28, overflow buffer tanks 51-56, water-oil separator 96, sensors 101-112, automatic detection and feeding controller 131, valves 132-1-132-23, pumps 133-1-133-23, cathode area etching waste liquid feeding pipe 134, acidic etching waste liquid 251, regenerated etching sub-liquid 252, recovered metallic copper 253, cathode electrolyte overflowed from electrolytic cell B 256 that has been processed for copper recovery, circuit board etching production line 257, oxidation regeneration etching liquid 260, and overflowed liquid 268 from the cathode area of ​​electrolytic cell A.

[0124] The separator 3 of the electrolytic cell A is an anion exchange membrane. The separator 4-1 of the electrolytic cell B is a bipolar membrane, and the separator 4-2 is a reverse osmosis membrane.

[0125] The anode material of the electrolytic cell A is an insoluble anode with a titanium-based coating, and the cathode material is titanium metal.

[0126] The anode material of the electrolytic cell B 2-1 is a titanium-based insoluble anode, and the cathode material is a metal copper sheet; the anode material of the electrolytic cell B 2-2 is conductive graphite, and the cathode material is a metal copper sheet.

[0127] Sensors 101 and 109 are hydrometers, sensor 102 is a pH meter, sensors 103, 106, and 111 are redox potentiometers (ORP meters), sensors 104 and 107 are thermometers, sensors 105, 108, and 112 are liquid level gauges, and sensor 110 is a photoelectric colorimeter. Field data from all sensors is transmitted to an automatic detection and feeding controller 131 for processing, which then controls the operation of the entire device according to a program.

[0128] Sensors 101, 102, 103, and 104 are installed in the circuit board etching production line 257. Sensor 102, a pH meter, controls pump 133-1 to add regenerated etching sub-liquid 252 to control the acidity of the etching working solution. Sensor 101, a hydrometer, controls a valve to add clean water 288 to control the specific gravity of the etching working solution. Sensor 103, an ORP meter, controls the speed of variable frequency pump 133-4 to maintain the redox potential of the etching working solution at 540 mV according to the process. Sensor 104, a thermometer, controls the temperature of the etching working solution at 50°C. Thus, by controlling the acidity of the etching working solution in circuit board etching line 257, the etching working solution maintains a pH of 0.9 mol / L, a specific gravity of 1.34 g / ml, and an ORP of 530 mV, thereby stabilizing etching performance.

[0129] The etching waste liquid overflowing from the circuit board etching production line 257 first flows into the water-oil separator 96 to separate the organic matter of the ink and film residue, and then flows into the liquid flow buffer tank 51, and is then pumped to the temporary storage tank 24 used as a circulating mixing exchange tank by the pump 133-3. When the oxidation regeneration etching liquid 260 in the temporary storage tank 24 is full, the sensor 105 liquid level meter controls the pump 133-7 to start part of the solution in the temporary storage tank 24 and pump it to the temporary storage tank 25 for temporary storage.

[0130] The circulating mixing exchange tank, or temporary storage tank 24, is connected to the circuit board etching line 257 via a circulating liquid flow pipeline and to the anode tank area of ​​electrolytic cells B 2-1 and 2-2 via a circulating liquid flow pipeline. The solution in the circulating mixing exchange tank is the oxidation regeneration etching solution 260. The redox potential value of the oxidation regeneration etching solution 260 in the temporary storage tank 24 is transmitted by the sensor 107 ORP meter to the automatic detection and feeding controller 131 for processing and regulating the operating current of the electrolytic power supplies 6-1 and 6-2, so that the redox potential value of the oxidation regeneration etching solution 260 is controlled within the range of 750-800 mV.

[0131] The redox potential controller 7 controls pump 133-10 to feed the waste etching solution 251 from temporary storage tank 25 into the cathode tank area of ​​electrolytic cell A. The overflow solution 268 after electrolysis is pumped by pump 133-9 to temporary storage in temporary storage tank 26. Since no metallic copper is deposited at cathode A during the electrolysis operation, the copper ion concentration in temporary storage tank 26 remains at approximately 140 g / L. The anode of electrolytic cell A is specifically used to generate chlorine gas to oxidize the cathode overflow solution 256 from electrolytic cells B 2-1 and 2-2 to prepare the regenerated etching sub-solution 252.

[0132] Electrolytic cells B 2-1 and 2-2 are progressive copper electrolytic cells. Their function is to electrolyze copper at the cathode and oxidize the anode, regenerating the etchant 260 to maintain the etching process. Sensor 109, a hydrometer, and sensor 110, a photoelectric colorimeter, respectively control pumps 133-13 and 133-14 to add overflow 268 from the cathode compartment of electrolytic cell A in temporary storage tank 26 to the cathode compartments of electrolytic cells B 2-1 and 2-2, achieving progressive copper electrolysis. During this process, the copper ion concentration in the cathode electrolyte of electrolytic cells B 2-1 and 2-2 was controlled to a set value of 40 g / L. Copper metal 253 was electrolytically deposited at the cathodes of both electrolytic cells B 2-1 and 2-2.

[0133] The cathode electrolyte 256 overflowing from the copper recovery electrolytic cells B 2-1 and 2-2 is pumped into the temporary storage tank 27. The sensor 111 ORP meter and the sensor 112 liquid level gauge control the pump 133-19 to be pumped into the temporary storage tank 28. Chlorine is sucked through the spray tower to oxidize the cathode electrolyte 256 overflowing from the copper recovery electrolytic cell B. The cuprous chloride and ferrous chloride in the solution are oxidized to form cupric chloride and ferric chloride copper etching agents, thereby producing a regenerated etching sub-liquid with a low copper ion concentration that meets the process requirements.

[0134] The cathode tank area etching waste liquid feeding pipes 296 and 297 of the electrolytic cells B 2-1 and 2-2 are used to add etching waste liquid to react and remove the cuprous chloride copper sludge on the separators 4-1 and 4-2 of the electrolytic cell B to avoid copper sludge clogging of the separators.

[0135] The acidic iron-containing etching waste liquid of this embodiment mainly comprises an aqueous solution of hydrochloric acid, cupric chloride, sodium chloride, ammonium chloride, ferric chloride, and ferrous chloride, wherein the acidity is 0.9 mol / L, the copper ion concentration is 140 g / L, and the total iron ion concentration is 20 g / L.

[0136] A device for progressive electrolysis to recycle circuit board acid etching waste liquid has the following main operating steps.

[0137] 1. Add etching working solution to the anode tank area of ​​electrolytic cell A and add etching waste liquid 251 to the cathode tank area as the starting electrolyte, wherein the anode tank area is installed with a sensor 101 liquid level gauge, and the cathode tank area of ​​electrolytic cell A is installed with an oxidation-reduction potential controller 7.

[0138] 2. The solution in the temporary storage tank 26 is added to the cathode tank area of ​​electrolytic cells B 2-1 and 2-2, and the electrolyte in the anode tank area of ​​electrolytic cell B circulates with the solution in the temporary storage tank 24 serving as a circulating mixing exchange tank.

[0139] 3. Turn on the electrolysis power supply 5 and the two electrolysis power supplies B 6-1 and 6-2 to cause electrolytic cell A and the two electrolytic cells B to perform electrolysis. During this process, the redox potential controller 7 is set to 499 mV to control the acidic etching waste liquid 251 to be directed to the cathode tank area of ​​electrolytic cell A. No metallic copper is generated on the cathode, and only a reaction to eliminate the copper-corroding agent occurs. The anode tank area of ​​electrolytic cell A is used for the electrolytic chlorine gas electrolysis reaction. The sensor 109 in electrolytic cell B 2-1 uses a hydrometer to monitor the overflow liquid 268 from the cathode tank area of ​​electrolytic cell A in the temporary storage tank 26. The overflow liquid 268 is then directed to the cathode tank area of ​​electrolytic cell B 2-1 via pump 133-14. The photoelectric colorimeter sensor 110 in electrolytic cell B 2-2 controls pump 133-13 to add the solution in the temporary storage tank 26 to the cathode tank area of ​​electrolytic cell B, causing copper to be electrolyzed on the cathodes of both electrolytic cells B 2-1 and 2-2. The anodes 2-1 and 2-2 perform an electrochemical oxidation reaction on the oxidized regeneration etching solution 260, allowing the circuit board etching production line 257 to maintain etching production by controlling the rotation speed and delivery rate of pump 133-4. At the same time, the chlorine gas escaping from the anode tank area of ​​electrolytic cell A is absorbed by the spray-type gas-liquid mixer 76 to prepare the regeneration etching sub-liquid 252 from the cathode electrolyte 256 overflowed from electrolytic cell B, which has been used for copper recovery. The cathode electrolyte of electrolytic cell A undergoes a reduction reaction to eliminate the copper corrosive agent. During the electrolysis process, a small amount of etching waste liquid 251 is added to the cathode tanks of electrolytic cells B 2-1 and 2-2 according to time control using metering pumps 133-11 and 133-12, respectively, to remove cuprous chloride on the separator.

[0140] 4. The working parameter indicators of the regenerated etching sub-liquid 252 are acidity 4.5M / L, copper ion concentration 40g / L, and iron ion concentration 20g / L.

[0141] The above is a 100% recycling process for recycling the acidic iron-containing etching waste liquid of the circuit board by using the device in Figure 2 and following the above process steps.

[0142] Example 3

[0143] FIG3 shows a third embodiment of a progressive electrolytic device for recycling waste acid etching liquid from circuit boards. The device comprises electrolytic cell A 1, electrolytic cells B 2-1 and 2-2, and electrolytic cell C 8. An oxidation-reduction potential controller 7 is installed in the cathode region of electrolytic cell A. Electrolytic cell A separator 3 is a bipolar membrane. Electrolytic cell B separators 4-1 and 4-22 are anion exchange membranes. Electrolytic cell C separator 9 is an anion exchange membrane. The system also includes an electrolytic power supply 5 for electrolytic cell A, electrolytic power supplies 6-1 and 6-2 for two electrolytic cells B, an electrolytic power supply 10 for electrolytic cell C, temporary storage tanks 23-31, overflow buffer tanks 51-56, a vacuum jet gas-liquid mixer 71, a spray-type gas-liquid mixer 76, circulating liquid agitators 81-86, sensors 110-112, an automatic detection and feeding controller 131, acidic etching waste liquid 251, regenerated etching sub-liquid 252, recovered metallic copper 253, overflow cathode electrolyte 256 from electrolytic cells B3-4 that has been processed for copper recovery, a circuit board etching production line 257, valves 132-1-132-19, pumps 133-1-133-20, sodium hydroxide solution 267, an exhaust gas treatment tank 281, overflow liquid 268 from the cathode tank area of ​​electrolytic cell A, clean water 288, and movable tank covers 289-291.

[0144] The anode material of electrolytic cell A is an insoluble anode with a gold-plated surface, and the cathode is platinum metal. The anode material of electrolytic cell B 2-1 is conductive graphite, and the cathode is a titanium plate. The anode material of electrolytic cell B 2-2 is an insoluble anode with a titanium-based coating, and the cathode is a titanium plate. The anode material of electrolytic cell C 8 is an insoluble anode with a titanium-based coating, and the cathode material is a copper sheet.

[0145] The circuit board etching production line 257 is connected to the anode tanks of electrolytic cells A and B via liquid flow pipes. Four sensors are installed on the circuit board etching production line 257: sensor 101, a pH meter; sensor 102, a hydrometer; sensor 103, a redox potential; and sensor 104, a thermometer. Sensor 101, a pH meter, controls pump 133-1 to add regenerated etching liquid 252; sensor 102, a hydrometer, controls the addition of clean water 288; and sensor 103, a redox potential, controls the output current of each electrolytic power source or shuts it down. When the copper etchant concentration in the etching solution reaches the set value, all electrolytic power sources are shut down. Sensor 104, a temperature controller, maintains the temperature of the etching solution at 50°C. By controlling the acidity, specific gravity, redox potential, and temperature parameters, the etching solution maintains its etching performance during the continuous etching process.

[0146] The overflow buffer tank 51 is equipped with an output pump pipeline equipped with a solid-liquid separation filter 97. This filter separates the organic oil residue floating on the etching solution, and then drains the waste etching solution into a temporary storage tank 25 to store the overflowed acidic etching solution 251. This embodiment does not include the aforementioned circulating mixing and exchange tank. During etching, pumps 133-4 through 133-6 are used to directly pump the etching solution into the anode tanks of electrolytic cells A and B, respectively. The solution then flows back to the circuit board etching production line 257 through the overflow ports of the respective anode tanks. Under the control of the ORP meter sensor 103, multiple electrolytic power supplies are activated or adjusted to respond, allowing the etching solution to oxidize and regenerate the copper etching agent.

[0147] The cathode region of electrolytic cell A is equipped with an ORP controller 7, set to 200 mV according to the process. This controls the amount of etching waste liquid 251 fed from temporary storage tank 25 to the cathode region of electrolytic cell A, converting all ferric ions in the cathode electrolyte into ferrous ions while minimizing the amount of copper electrolytically deposited at the cathode. The treated overflow liquid 268 from the cathode region of electrolytic cell A is pumped by pump 133-7 to temporary storage tank 26, where the copper ion concentration of the solution is reduced to 98 g / L.

[0148] Electrolytic Cell B utilizes a progressive electrolytic copper extraction process similar to that of Electrolytic Cell A, while Electrolytic Cell C utilizes a further progressive electrolytic copper extraction process. Hydrometers, namely sensors 105 and 106, are installed in the cathode tank area of ​​Electrolytic Cell B. Sensor 107, an ORP meter, is installed in the anode tank area of ​​Electrolytic Cell C, and sensor 108, a hydrometer, is installed in the cathode tank area of ​​Electrolytic Cell C. The detection data from these multiple sensors is sent to an automatic detection and feeding controller 131 for processing. This controls the overflow liquid 268 from the cathode tank area of ​​Electrolytic Cell A in the temporary storage tank 26 to be fed to the cathode tank area of ​​Electrolytic Cell B. This allows the concentrations of various components in the electrolyte in each cathode tank area of ​​Electrolytic Cell B to be controlled during the copper electrolysis process. The cathode overflow liquid from Electrolytic Cell B is pumped by pumps 133-11 and 133-12 to a temporary storage tank 27 for temporary storage. The copper ion concentration of the solution in temporary storage tank 27 is set to 60 g / L.

[0149] Based on data measured by sensor 108, the automatic detection feed controller 131 controls pump 133-13 to feed solution 256 into the cathode tank of electrolytic cell C. Sensor 108's hydrometer controls the copper ion concentration of electrolytic cell C's catholyte at 5 g / L. During the electrolysis process, sponge copper is produced and collected by cathode cloth filter bag 294. As electrolytic cell C continues to operate, its catholyte overflows into overflow buffer tank 56 and is pumped by pump 133-18 to temporary storage tank 30.

[0150] Temporary storage tank 31 serves as a chlorine oxidation reaction tank. A vacuum jet gas-liquid mixer 71 is installed on its top, and a level gauge, sensor 109, is installed within the tank. During the process, chlorine gas escaping from the anode compartment of each electrolytic cell is channeled into temporary storage tank 31 to react with the solution within the tank. Sensor 109, a level gauge, controls pump 133-19 to inject the solution into temporary storage tank 31. Sensor 107, an ORP meter, controls pump 133-20 to inject the solution from temporary storage tank 31 into the anode compartment of electrolytic cell C. This ensures that the cuprous chloride and ferrous chloride in the cathode electrolyte of electrolytic cell C, after copper extraction, are oxidized into a copper etchant, meeting certain standard requirements for regenerated etching sub-solvents.

[0151] The temporary storage tank 28 is used to prepare the regeneration etching sub-liquid. After the solution in the temporary storage tank 29 is added, hydrochloric acid, ferric chloride, and ammonium chloride are added, and the liquid circulation agitator 84 is activated to prepare the regeneration etching sub-liquid 252. After passing manual inspection, the prepared regeneration etching sub-liquid 252 is pumped to the temporary storage tank 23 for temporary storage.

[0152] The tail gas treatment tank 281 is used to absorb the acidic tail gas S emitted from each tank for environmental protection.

[0153] During the etching production process, the redox potential of the etching working solution is controlled at 580mv.

[0154] The acidic iron-containing etching waste liquid of this embodiment mainly comprises an aqueous solution of hydrochloric acid, cupric chloride, ammonium chloride and ferric chloride, wherein the acidity is 1.6 mol / L, the copper ion concentration is 100 g / L, and the total iron ion concentration is 140 g / L.

[0155] The operating steps of a device for progressive electrolysis to recycle circuit board acid etching waste liquid are as follows.

[0156] 1. Add etching working liquid to the anode tank area of ​​electrolytic cell A and add etching waste liquid 251 to the cathode tank area. The cathode tank area of ​​electrolytic cell A is equipped with an oxidation-reduction potential controller 7 to control the amount of etching waste liquid 251 added to the cathode tank area of ​​electrolytic cell A during the electrolysis process. The ORP value of the cathode electrolyte is controlled to be 200mv.

[0157] 2. Add etching working liquid to the anode tank areas of the two electrolytic cells B, and add the overflow liquid 268 of the cathode tank area of ​​electrolytic cell A in the temporary storage tank 26 to the cathode tank area of ​​electrolytic cell B. Use sensors 105 and 106 hydrometers to control the amount of overflow liquid 268 from the cathode tank area of ​​electrolytic cell A added to each cathode tank area of ​​electrolytic cell B during the process.

[0158] 3. The ORP meter of sensor 107 controls the addition of the solution from temporary storage tank 31 to the anode tank area of ​​electrolytic cell C. The hydrometer of sensor 108 controls the pump 133-13 to add the cathode electrolyte 256 overflowed from electrolytic cell B that has been processed for copper recovery in temporary storage tank 27 to the cathode tank area of ​​electrolytic cell C.

[0159] 4. Turn on the electrolysis power supply, causing each electrolytic cell to perform electrolysis. During this process, the etching solution in the etching production line 257 circulates between the anode compartments of electrolytic cells A and B, causing each electrolytic anode to undergo an electrochemical reaction that oxidizes and regenerates the etching solution. Chlorine gas released from the anode compartments of electrolytic cells A and B is directed to a temporary storage tank 31, where it is used to oxidize electrolyte overflow from the cathode compartment of electrolytic cell C, which has been processed for copper recovery. Metallic copper 253 is electrolytically deposited at the cathodes of both electrolytic cells B and C.

[0160] 5. Hydrochloric acid, ferric chloride, and ammonium chloride are added to the oxidized solution in temporary storage tank 28 to prepare a regeneration etching solution. After passing manual inspection, the solution in tank 28 is pumped via pump 133-15 to temporary storage in temporary storage tank 23. The parameters of the regeneration etching solution 252 are acidity 5.5 M / L, copper ion concentration 5 g / L, and ferric ion concentration 140 g / L.

[0161] 6. The acidic tail gas S emitted from each tank is led to the tail gas treatment tank 281 for environmental protection treatment.

[0162] 7. The process flow of the entire equipment system is automatically controlled by the automatic detection and feeding controller 131 according to the program, and the regenerated etching sub-liquid in the temporary storage tank 23 is fed into the etching line for recycling.

[0163] The above is a 100% recycling process for recycling the waste acid etching solution of the circuit board by progressive electrolysis using the device of FIG3 and following the above steps.

[0164] Example 4

[0165] As shown in FIG4, a method and apparatus for recycling acidic etching waste liquid of circuit boards by progressive electrolysis is shown in Example 4, which includes an electrolytic cell A1, two electrolytic cells B 2-1 and 2-2, cathode region redox potential controller 7 for electrolytic cell A, separator 3 for electrolytic cell A, separators 4-1 and 4-2 for electrolytic cell B, electrolytic power supply 5 for electrolytic cell A, electrolytic power supplies 6-1 and 6-2 for two electrolytic cells B, temporary storage tanks 23-28, overflow buffer tanks 51-56, water-oil separator 96, sensors 101-112, automatic detection and feeding controller 131, valves 132-1-132-20, pumps 1331-133-20, acidic etching waste liquid 251, regenerated etching sub-liquid 252, recovered metallic copper 253, cathode electrolyte overflowed from electrolytic cell B 256 that has been processed for copper recovery, circuit board etching production line 257, oxidation regeneration etching liquid 260, and overflowed liquid 268 from the cathode region of electrolytic cell A.

[0166] The separator 3 of the electrolytic cell A is an anion exchange membrane. The separator 4-1 of the electrolytic cell B is a bipolar membrane, and 4-2 is a reverse osmosis membrane.

[0167] The anode material of the electrolytic cell A is an insoluble anode with a titanium-based coating, and the cathode material is titanium metal.

[0168] The anode material of the electrolytic cell B 2-1 is a titanium-based insoluble anode, and the cathode material is a metal copper sheet; the anode material of the electrolytic cell B 2-2 is conductive graphite, and the cathode material is a metal copper sheet.

[0169] Sensor 101 is a pH meter; sensors 102, 106, and 111 are redox potentiometers (ORP meters); sensors 103 and 107 are thermometers; sensors 104 and 109 are hydrometers; sensors 105 and 112 are liquid level gauges; and sensor 110 is a photoelectric colorimeter. Field detection data from all sensors is transmitted to an automatic detection and feeding controller 131 for processing, which then controls the operation of the entire device according to a program.

[0170] The circuit board etching production line 257 is equipped with sensors 101 to 103. Sensor 101, a pH meter, controls the valve that adds external acidic ferric chloride solution to control the acidity of the etching solution. Sensor 102, an ORP meter, controls the speed of variable frequency pump 133-4 to maintain the etching solution's redox potential at 510 mV according to the process. Sensor 103, a thermometer, maintains the etching solution's temperature at 50°C. The specific gravity of the etching solution is monitored and controlled by sensor 104, a hydrometer installed in the circulating mixing and exchange tank. When the solution's specific gravity in the circulating mixing and exchange tank increases due to copper etching, pump 133-1 controls the solution from the temporary storage tank 23 to the circulating mixing and exchange tank, reducing the copper ion concentration in the solution. Thus, circuit board etching production line 257 maintains the etching solution's acidity at 1 mol / L, specific gravity at 1.33 g / ml, and ORP at 510 mV through these controlled dosing procedures, thereby stabilizing etching performance.

[0171] The etching waste liquid overflowing from the circuit board etching production line 257 first flows into the water-oil separator 96 to separate the organic matter of the ink and film residue, and then flows into the liquid flow buffer tank 51, and is then pumped to the temporary storage tank 24 used as a circulating mixing exchange tank by the pump 133-3. When the oxidation regeneration etching liquid 260 in the temporary storage tank 24 is full, the sensor 105 liquid level meter controls the pump 133-7 to start part of the solution in the temporary storage tank 24 and pump it to the temporary storage tank 25 for temporary storage.

[0172] The circulating mixed exchange tank, i.e., the temporary storage tank 24, is connected to the circuit board etching production line 257 by a circulating liquid flow pipeline, and is connected to the anode tank area of ​​the electrolytic tank A and the electrolytic tank B by a circulating liquid flow pipeline. The redox potential value of the oxidized regeneration etching solution 260 in the temporary storage tank 24 is transmitted to the automatic detection and feeding controller 131 through the sensor 107 ORP meter to process the field parameters and adjust the working current of the two electrolytic power supplies B, so that the redox potential value range of the circulating mixed exchange tank solution 260 is controlled within 750-800mv. According to the value detected by the hydrometer of the sensor 104 installed in the circulating mixed exchange tank, the regenerated etching sub-liquid in the temporary storage tank 23 is not fed to the etching line but directly fed to the circulating mixed exchange tank, which can quickly balance the copper ion concentration of the etching working solution and quickly oxidize the Fe2+ still remaining in the regenerated etching sub-liquid. 2+ Ferrous ions make the ORP value of the etching solution more stable.

[0173] The redox potential controller 7 controls pump 133-11 according to the process settings to feed the etching waste liquid 251 from temporary storage tank 25 into the cathode tank area of ​​electrolytic cell A. The overflow liquid 268 after electrolysis is pumped by pump 133-10 to temporary storage in temporary storage tank 26. During the electrolysis operation, because no metallic copper is deposited at the cathode of electrolytic cell A, the copper ion concentration of the solution in temporary storage tank 26 remains at 120 g / L. The anode of electrolytic cell A is used to oxidize the etching working solution.

[0174] Electrolytic Cell B is a sequential copper electrolytic cell for electrolytic Cell A. Its cathode is used for copper electrolysis, while its anode oxidizes the oxidized regenerated etching solution 260 to maintain etching. Sensor 109, a hydrometer, and sensor 110, a photoelectric colorimeter, respectively control pumps 133-12 and 133-13 to feed overflow 268 from the cathode region of Electrolytic Cell A in temporary storage tank 26 into the cathode regions of both Electrolytic Cells B, achieving progressive copper electrolysis. During this process, the copper ion concentration in the cathode electrolyte of Electrolytic Cell B is controlled to a set value of 30 g / L. Copper metal 253 is deposited at the cathodes of both Electrolytic Cells B.

[0175] The cathode electrolyte 256 overflowing from electrolytic cell B, which has been processed for copper recovery, is pumped to temporary storage tank 27 via pumps 133-15 and 133-17. It is then pumped to temporary storage tank 28 via pump 133-18 controlled by sensor 111, an ORP meter, and sensor 112, a liquid level gauge. Chlorine gas escaping from the electrolytic cell's anolyte is drawn through a spray tower to oxidize the cathode electrolyte 256 overflowing from electrolytic cell B, which has been processed for copper recovery. This oxidizes some of the cuprous chloride and ferrous chloride in the solution into copper chloride and ferric chloride, a copper etching agent, producing a regenerated etching liquid with a low copper ion concentration. A certain amount of divalent iron ions not oxidized by the chlorine gas still remain in the regenerated etching liquid.

[0176] The acidic iron-containing etching waste liquid of this embodiment mainly comprises an aqueous solution of hydrochloric acid, cupric chloride, sodium chloride, ammonium chloride, ferric chloride, and ferrous chloride, wherein the acidity is 1 mol / L, the copper ion concentration is 120 g / L, and the total iron ion concentration is 120 g / L.

[0177] A device for progressive electrolysis to recycle circuit board acid etching waste liquid has the following main operating steps.

[0178] 1. Add etching working solution to the anode tank area of ​​electrolytic cell A and add etching waste liquid 251 to the cathode tank area as the starting electrolyte, wherein the redox potential controller 7 installed in the cathode tank area of ​​electrolytic cell A sets the setting value of the redox potential controller 7 to 470mV during the electrolysis operation to control the amount of etching waste liquid 251 added to the cathode tank area of ​​electrolytic cell A, and no metallic copper is generated on the cathode, only a reaction to eliminate the copper etching agent occurs, and the anode tank area of ​​electrolytic cell A is used for the oxidation reaction of the etching working solution.

[0179] 2. The solution in the temporary storage tank 26 is added to the cathode tank area of ​​the two electrolytic cells B, and the electrolyte in the anode tank circulates with the solution in the temporary storage tank 24 used as a circulating mixing exchange tank.

[0180] 3. Turn on the electrolysis power supply 5 and the electrolysis power supply 6 to make electrolytic cell A and electrolytic cell B perform electrolysis. During this process, the redox potential controller 7 monitors the etching waste liquid 251 and discharges it to the cathode tank area of ​​electrolytic cell A. The sensor 109 in electrolytic cell B 2-1 monitors the overflow liquid 268 from the cathode tank area of ​​electrolytic cell A in the temporary storage tank 26 and discharges it to the cathode tank area of ​​electrolytic cell B through the pump 133-13. The sensor 110 photoelectric colorimeter in 2-2 controls the pump 133-12 to add the solution of the temporary storage tank 26 to the cathode tank area of ​​the electrolytic cell B, so that copper is electrolyzed on the cathodes of the electrolytic cell B; the anode of the electrolytic cell B performs an electrochemical oxidation reaction on the oxidized regeneration etching solution 260, so that the etching production line 257 maintains the etching production by controlling the rotation speed and delivery amount of the pump 133-4; at the same time, the small amount of chlorine gas escaping from the anode tank area of ​​each electrolytic cell is absorbed by the spray-type gas-liquid mixer 76 to prepare the regeneration etching sub-liquid 252 from the cathode electrolyte 256 overflowed from the electrolytic cell B that has been processed for copper recovery.

[0181] 4. The working parameter indicators of the regenerated etching sub-liquid 252 are acidity 6M / L, copper ion concentration 30g / L, and iron ion concentration 120g / L.

[0182] The above is a 100% recycling process for recycling the acidic iron-containing etching waste liquid of the circuit board by using the device in Figure 4 and following the above process steps.

[0183] Example 5

[0184] The following acidic etching waste liquid was treated using the apparatus shown in FIG1 .

[0185] The acidic etching waste liquid of this embodiment mainly comprises hydrochloric acid, copper chloride, and water, wherein the acidity is 3.2 mol / L, the copper ion concentration is 120 g / L, and the oxidation-reduction potential (ORP) value is 500 mv.

[0186] The specific steps of this embodiment are as follows.

[0187] 1. Acidic etching waste liquid 251 is added to the anode tank area and cathode tank area of ​​electrolytic cell A as the initial electrolyte. During the electrolysis operation, the amount of acidic etching waste liquid 251 added to the cathode tank area of ​​electrolytic cell A is controlled to cause the divalent copper ions in the etching waste liquid to undergo an electrochemical reduction reaction. The cathode tank area overflows into the temporary storage tank 25 due to full liquid.

[0188] 2. Add the overflow liquid 268 from the cathode tank area of ​​electrolytic cell A in the temporary storage tank 25 to the cathode tank area of ​​electrolytic cell B, and add the cathode electrolyte 256 overflowed from electrolytic cell B that has been processed for copper recovery in the temporary storage tank 27 to its anode tank area.

[0189] 3. Manually connect electrolysis power supply 5 and electrolysis power supply 6 to electrolyze electrolytic cell A and electrolytic cell B. During the electrolysis process, the anode region of electrolytic cell A electrolyzes to produce chlorine gas. The redox potential controller 7 is set to control the redox potential to 300 mV, monitors the acidic etching waste liquid 251 and delivers it to the cathode region of electrolytic cell A, thereby reducing the copper etching agent concentration in the cathode electrolyte and controlling the absence of electrolytic copper deposition on the electrolytic cathode of electrolytic cell A. The sensor 103 in electrolytic cell B monitors the overflow liquid 268 from the cathode region of electrolytic cell A in the temporary storage tank 25 via pump 133-3 and delivers it to the cathode region of electrolytic cell B, thereby controlling the copper ion concentration of the cathode electrolyte. The anodes of electrolytic cell A and electrolytic cell B respectively perform electrochemical oxidation reactions on the acidic etching waste liquid 251 and the catholyte 256 overflowing from electrolytic cell B, which has been processed for copper recovery. Simultaneously, chlorine gas emitted from the anode tanks of electrolytic cells A and B is mixed with gas through ejector 71 to oxidize the solution in temporary storage tank 28 to generate regenerated etching sub-liquid 252. The catholyte in electrolytic cell A undergoes a reduction reaction to eliminate the copper-corroding agent, while the cathode of electrolytic cell B electrolytically deposits metallic copper 253. The anode of electrolytic cell B is used to oxidize the catholyte 256 overflowing from electrolytic cell B, which has been processed for copper recovery, to prepare the regenerated etching sub-liquid.

[0190] 4. The parameter values ​​of the regenerated etching liquid are acidity 4.0M / L, copper ion concentration 60g / L, and ORP value 520mv.

[0191] The above is a process for recycling the acidic etching waste liquid of the circuit board by progressive electrolysis, which can be achieved by using the device in Figure 1 and following the above process steps.

[0192] Example 6

[0193] The following acidic etching waste liquid was treated using the apparatus shown in FIG3 .

[0194] The acidic etching waste liquid of this embodiment mainly comprises hydrochloric acid, cupric chloride, ammonium chloride, and water, wherein the acidity is 2.5 mol / L, the copper ion concentration is 120 g / L, and the oxidation-reduction potential (ORP) value is 520 mV.

[0195] The specific steps of this embodiment are as follows.

[0196] 1. Add etching working liquid to the anode tank area of ​​electrolytic cell A and add acidic etching waste liquid 251 to the cathode tank area. The cathode tank area is equipped with an oxidation-reduction potential controller 7 to control the amount of etching waste liquid 251 added to the cathode tank area of ​​electrolytic cell A during the electrolysis process. The ORP value of the cathode electrolyte is controlled to be 350mv.

[0197] 2. Add etching working liquid to the anode tank area of ​​the two electrolytic cells B, and add the overflow liquid 268 of the cathode tank area of ​​electrolytic cell A in the temporary storage tank 26 to the cathode tank area of ​​electrolytic cell B. Use sensors 105 and 106 hydrometers to control the amount of overflow liquid 268 from the cathode tank area of ​​electrolytic cell A added to each cathode tank area of ​​electrolytic cell B during the process.

[0198] 3. The solution from the temporary storage tank 31 is controlled to be added to the anode tank area of ​​electrolytic cell C through the ORP meter sensor 107, and the cathode electrolyte 256 overflowed from electrolytic cell B that has been processed for copper recovery in the temporary storage tank 27 is controlled to be added to the cathode tank area of ​​electrolytic cell C through the hydrometer sensor 108 133-13.

[0199] 4. Turn on the electrolysis power supply, causing each electrolytic cell to perform electrolysis. During this process, the etching solution in the circuit board etching production line 257 circulates between the anode compartments of electrolytic cells A and B, causing each electrolytic anode to electrochemically oxidize and regenerate the etching solution. Chlorine gas released from the anode compartments of electrolytic cells A and B is drained into a temporary storage tank 31, where it is used to oxidize electrolyte overflow from the cathode compartment of electrolytic cell C, which has been processed for copper recovery. Metallic copper 253 is electrolytically deposited at the cathodes of both electrolytic cells B and C.

[0200] 5. Hydrochloric acid and ammonium chloride are added to the oxidized solution in temporary storage tank 28 to prepare a regeneration etching solution. After passing manual inspection, the solution in tank 28 is pumped via pump 133-15 to temporary storage tank 23. The parameters of the regeneration etching solution 252 are an acidity of 6.1 M / L and a copper ion concentration of 5 g / L.

[0201] 6. The acidic tail gas S emitted from each tank is led to the tail gas treatment tank 281 for environmental protection treatment.

[0202] 7. The process flow of the entire equipment system is automatically controlled by the automatic detection and feeding controller 131 according to the program, and the regenerated etching sub-liquid in the temporary storage tank 23 is fed into the etching line for recycling.

[0203] The above is a 100% recycling process for recycling the waste acid etching solution of the circuit board by progressive electrolysis using the device of FIG3 and following the above steps.

[0204] Example 7

[0205] The following acidic etching waste liquid was treated using the apparatus shown in FIG4 .

[0206] The acidic etching waste liquid of this embodiment mainly comprises hydrochloric acid, copper chloride, sodium chloride, and water, with an acidity of 2.7 mol / L, a copper ion concentration of 110 g / L, and an oxidation-reduction potential (ORP) value of 480 mV.

[0207] The specific steps of this embodiment are as follows.

[0208] 1. Add etching working solution to the anode tank area of ​​electrolytic cell A and add acidic etching waste liquid 251 to the cathode tank area as the initial electrolyte, wherein the redox potential controller 7 installed in the cathode tank area of ​​electrolytic cell A sets the setting value of the redox potential controller 7 to 300mV during the electrolysis operation to control the amount of acidic etching waste liquid 251 added to the cathode tank area of ​​electrolytic cell A, and no metallic copper is generated on the cathode, only a reaction to eliminate the copper etching agent occurs, and the anode tank area of ​​electrolytic cell A is used for the oxidation reaction of the etching working solution.

[0209] 2. The solution in the temporary storage tank 26 is added to the cathode tank area of ​​the two electrolytic cells B, and the electrolyte in the anode tank circulates with the solution in the temporary storage tank 24 used as a circulating mixing exchange tank.

[0210] 3. Turn on the electrolysis power supply 5 and the electrolysis power supply 6 to make electrolytic cell A and electrolytic cell B perform electrolysis. During this process, the redox potential controller 7 monitors the etching waste liquid 251 and discharges it to the cathode tank area of ​​electrolytic cell A. The sensor 109 in electrolytic cell B 2-1 monitors the overflow liquid 268 from the cathode tank area of ​​electrolytic cell A in the temporary storage tank 26 and discharges it to the cathode tank area of ​​electrolytic cell B through the pump 133-13. The sensor 110 photoelectric colorimeter in 2-2 controls the pump 133-12 to add the solution of the temporary storage tank 26 to the cathode tank area of ​​the electrolytic cell B, so that copper is electrolyzed on the cathodes of the electrolytic cell B; the anode of the electrolytic cell B performs an electrochemical oxidation reaction on the oxidized regeneration etching solution 260, so that the etching production line 257 maintains the etching production by controlling the rotation speed and delivery amount of the pump 133-4; at the same time, the small amount of chlorine gas escaping from the anode tank area of ​​each electrolytic cell is absorbed by the spray-type gas-liquid mixer 76 to prepare the regeneration etching sub-liquid 252 from the cathode electrolyte 256 overflowed from the electrolytic cell B that has been processed for copper recovery.

[0211] 4. The working parameter indicators of the regenerated etching sub-liquid 252 are acidity 5.2M / L and copper ion concentration 30g / L.

[0212] The above is a 100% recycling process for recycling the circuit board acid etching waste liquid by progressive electrolysis by using the device in Figure 4 and following the above process steps.

[0213] Example 8

[0214] As shown in FIG5 , a method and apparatus for recycling acidic etching waste liquid of circuit boards by progressive electrolysis is shown in Example 8, which comprises two electrolytic cells A 1-1 and 1-2, two electrolytic cells B 2-1 and 2-2, an oxidation-reduction potential controller 7-1 is installed in the cathode tank area of ​​electrolytic cell A 1-1, and electrolytic cell A The cathode tank area of ​​1-2 is equipped with an oxidation-reduction potential controller 7-2, electrolytic cell A separators 3-1 and 3-2, electrolytic cell B separators 4-1 and 4-2, two electrolytic power supplies 5-1 and 5-2, two electrolytic power supplies 6-1 and 6-2, temporary storage tanks 23-28, 9 overflow buffer tanks, a water-oil separator 96, sensors 101-116, an automatic detection and feeding controller 131, a valve 132, a pump 133, an exhaust gas treatment tank 281, a cathode tank area etching waste liquid feeding pipe 134, acid etching waste liquid 251, regenerated etching sub-liquid 252, recovered metallic copper 253, cathode electrolyte 256 overflowed from electrolytic cell B that has been processed for copper recovery, a circuit board etching production line 257, oxidation regeneration etching liquid 260, and overflow 268 from the cathode tank area of ​​electrolytic cell A.

[0215] The two separators 3-1 and 3-2 of the electrolytic cell A are both anion exchange membranes. The separators 4-1 and 4-2 of the electrolytic cell B are both anion exchange membranes.

[0216] The anode materials of the two electrolytic cells A 1-1 and 1-2 are both titanium-based coated insoluble anodes, and the cathode materials are both titanium metal.

[0217] The anode materials of the electrolytic cells B 2-1 and 2-2 are both titanium-based coated insoluble anodes; the cathode materials of the electrolytic cells B 2-1 and 2-2 are both metal copper sheets.

[0218] Sensors 101, 111, 112, and 113 are hydrometers; sensors 102 and 114 are acid meters; sensors 103, 106, 109, and 111 are redox potentiometers (ORP meters); sensors 104 and 107 are thermometers; and sensors 105, 108, 110, and 116 are liquid level gauges. Field data from all sensors is transmitted to an automatic detection and feeding controller 131 for processing, which then controls the operation of the entire device according to a program.

[0219] The circuit board etching production line 257 is equipped with sensors 101, 102, 103, and 104. Sensor 101, a hydrometer, controls pump 133-1 to add regenerated etching solution 252 to control the chloride concentration of the etching solution. Sensor 102, a pH meter, controls valve 132-2 to add hydrochloric acid 283 to control the acidity of the etching solution. Sensor 103, an ORP meter, controls the speed of variable frequency pump 133-4 to maintain the redox potential of the etching solution at 530 mV according to the process. Sensor 104, a thermometer, controls the temperature of the etching solution at 50°C. Thus, circuit board etching line 257 maintains the etching solution's acidity at 0.9 mol / L, specific gravity at 1.35 g / ml, and ORP at 530 mV through these controlled additions, thereby stabilizing etching performance.

[0220] The etching waste liquid overflowing from the circuit board etching production line 257 first flows into the water-oil separator 96 to separate the organic matter of the ink and film residue, and then flows into the liquid flow buffer tank 51, and is then pumped to the temporary storage tank 24 used as a circulating mixing exchange tank. When the oxidation regeneration etching liquid 260 in the temporary storage tank 24 is full, the sensor 105 liquid level meter controls the pump 133-7 to start part of the solution in the temporary storage tank 24 and pump it to the temporary storage tank 25 for temporary storage.

[0221] The working conditions of the two electrolytic cells A1-1 and 1-2 are controlled by the on-site detection values ​​of the liquid level meters 110 and 116. The electrolytic cell A1-2 is used to electrolytically oxidize the 256 solution from the electrolytic cell B to regenerate the etching liquid.

[0222] The circulating mixing exchange tank, or temporary storage tank 24, is connected to the circuit board etching line 257 via a circulating liquid flow pipeline and is connected to the anode tank areas of electrolytic cell A 1-1 and electrolytic cells B 2-1 and 2-2 via a circulating liquid flow pipeline. The solution in the circulating mixing exchange tank is the oxidation regeneration etching solution 260. The redox potential value of the oxidation regeneration etching solution 260 in the temporary storage tank 24 is transmitted by the sensor 106 ORP meter to the automatic detection and feeding controller 131 for processing. The automatic detection and feeding controller 131 adjusts and controls the operating current of the electrolytic power supply 5-1 and the electrolytic power supplies 6-1 and 6-2, respectively, so that the redox potential value of the oxidation regeneration etching solution 260 is controlled within the range of 750 to 850 mV.

[0223] Oxidation-reduction potential controllers 7-1 and 7-2 control pumps 133-14 and 133-13, respectively, to feed waste etching solution 251 from temporary storage tank 25 to the cathode regions of two electrolytic cells A. After electrolysis, overflow solution 268 is pumped to temporary storage tank 26. Since no metallic copper is deposited at the cathodes of either electrolytic cell A during electrolysis, the copper ion concentration of the solution in temporary storage tank 26 remains approximately 140 g / L.

[0224] Electrolytic cells B 2-1 and 2-2 are progressive copper electrolytic cells, with the cathodes performing copper electrolysis and the anodes oxidizing the regenerated etching solution 260 to maintain the etching process. Hydrometers 111 and 112 control pumps 133-18 and 133-17, respectively, to feed overflow 268 from the cathode compartments of electrolytic cell A in the temporary storage tank 26 into the cathode compartments of electrolytic cells B 2-1 and 2-2, achieving progressive copper electrolysis. During this process, the copper ion concentration in the cathode electrolyte of both electrolytic cells B 2-1 and 2-2 was controlled to a set value of 40 g / L, and copper metal 253 was deposited at the cathodes of both electrolytic cells B 2-1 and 2-2.

[0225] The cathode electrolyte 256 overflowing from the copper-recovered electrolytic cells B 2-1 and 2-2 is pumped to a temporary storage tank 27. The solution from tank 27 is then pumped to a temporary storage tank 28 for preparation by controlling a pump 113-23, controlled by a hydrometer sensor 113 and a pH meter sensor 114. During this process, an impeller agitator 92 is activated, and hydrochloric acid 283, ammonium chloride 285, and ferric hydroxide 297 are added to tank 28 to prepare the anolyte for electrolytic cell A 1-2.

[0226] The cathode tank area etching waste liquid feeding pipes 296 and 297 of the electrolytic cells B 2-1 and 2-2 are used to add etching waste liquid to react and remove the cuprous chloride copper sludge on the separators 4-1 and 4-2 of the electrolytic cell B to avoid copper sludge clogging of the separators.

[0227] The tail gas treatment tank 281 adopts a spray tower to introduce the waste gas for treatment.

[0228] The acidic iron-containing etching waste liquid of this embodiment mainly comprises an aqueous solution of hydrochloric acid, cupric chloride, sodium chloride, ammonium chloride, ferric chloride, and ferrous chloride, wherein the acidity is 0.9 mol / L, the copper ion concentration is 140 g / L, and the total iron ion concentration is 30 g / L.

[0229] A device for progressive electrolysis to recycle circuit board acid etching waste liquid has the following main operating steps.

[0230] 1. Add etching working solution to the anode tank area of ​​electrolytic cell A1-1 and add etching waste liquid 251 to the cathode tank area as the starting electrolyte. The anode electrolyte of electrolytic cell A1-1 and the circulating mixed exchange tank solution can circulate. Add the etching sub-liquid (tank 28 solution) that needs to be regenerated and oxidized to the anode tank area of ​​electrolytic cell A1-2. The anode tank area of ​​electrolytic cell A1-1 is equipped with sensor 101, a liquid level gauge, and the anode tank area of ​​electrolytic cell A1-2 is equipped with sensor 109, an ORP meter. The cathode tank areas of the two electrolytic cells A are equipped with redox potential controllers 7-1 and 7-2, respectively.

[0231] 2. The solution in the temporary storage tank 26 is added to the cathode tank area of ​​electrolytic cells B 2-1 and 2-2, and the electrolyte in the anode tank area circulates with the solution in the temporary storage tank 24 serving as a circulating mixing exchange tank.

[0232] 3. Turn on the electrolysis power supplies 5-1 and 5-2 of the two electrolytic cells A and the electrolysis power supplies 6-1 and 6-2 of the two electrolytic cells B to allow the two electrolytic cells A and the two electrolytic cells B to perform electrolysis operations. During this process, the set values ​​of the redox potential controllers 7-1 and 7-2 are both set to 480 mV to control the acidic iron-containing etching waste liquid 251 to be directed to the cathode tank areas of the two electrolytic cells A. No metallic copper is generated on the two cathodes and only a reaction to eliminate the copper etching agent occurs. The anodes of the two electrolytic cells A respectively perform an oxidation reaction on the anolyte. The sensor 111 hydrometer in the electrolytic cell B 2-1 monitors the overflow liquid 268 from the cathode tank area of ​​the electrolytic cell A in the temporary storage tank 26. The overflow liquid 268 is then directed to the cathode tank area of ​​the electrolytic cell B 2-1 via the pump 133-18. The sensor 112 hydrometer in the electrolytic cell B 2-2 controls the pump 133-17 to add the solution in the temporary storage tank 26 to the two cathode tank areas of the electrolytic cell B, so that the electrolytic cell B The cathodes in electrolytic cells B 2-1 and 2-2 are both electrolytically coated with copper. The anodes in electrolytic cells B 2-1 and 2-2 electrochemically oxidize the oxidized regenerated etching solution 260, allowing the circuit board etching production line 257 to maintain etching production by controlling the speed and delivery rate of pump 174. During the electrolysis process, a metering pump is used to add a small amount of etching waste liquid 251 to the cathode tanks of electrolytic cells B 2-1 and 2-2 according to time control to remove cuprous chloride on the separator of electrolytic cell B.

[0233] 4. The cathode overflow liquid of the two electrolytic cells B is collected in the temporary storage tank 27. According to the data detected by the sensors 113 and 114 in the temporary storage tank 28, the 256 solution is controlled to be added to the tank 28 respectively. Hydrochloric acid, ammonium chloride and ferric hydroxide are prepared to prepare the anolyte of the electrolytic cell A 1-2.

[0234] 5. According to the on-site detection value of the ORP meter of sensor 109, pump 133-24 is controlled to input the solution in tank 28 into the anode tank area of ​​electrolytic tank A1-2, and the regenerated etching sub-liquid that meets the process requirements is obtained through electrochemical oxidation for recycling in etching production.

[0235] The above is a 100% recycling process for recycling the circuit board acid etching waste liquid by progressive electrolysis by using the device in Figure 5 and following the above process steps.

Claims

1. A method for recycling circuit board acid etching waste liquid by progressive electrolysis, characterized in that: The following steps are involved: Step 1: using at least one electrolytic cell A, wherein the electrolytic cell A is separated into an anode cell area and a cathode cell area by an electrolytic cell separator; during electrolysis operation, the anode cell area and the cathode cell area of ​​the electrolytic cell A are respectively provided with an electrolytic anode and an electrolytic cathode, and electrolysis operation is performed on the anolyte and catholyte of the electrolytic cell A respectively; the catholyte of the electrolytic cell A contains acidic etching waste liquid; Step 2: Using at least one electrolytic cell B for progressive electrolysis to extract copper, the electrolytic cell B is divided into an anode cell area and a cathode cell area; during the electrolysis operation, the anode cell area and the cathode cell area of ​​the electrolytic cell B are respectively provided with an electrolytic anode and an electrolytic cathode, and electrolysis operations are performed on the anolyte and the catholyte of the electrolytic cell B respectively, so that an electrochemical reaction occurs at the electrolytic cathode of the electrolytic cell B, in which copper ions are reduced to metallic copper; The cathode electrolyte of the electrolytic cell B comprises the cathode electrolyte of the electrolytic cell A after electrolysis treatment or a mixture thereof with acidic etching waste liquid; Step 3: When the amount of metallic copper deposited on the electrolytic cathode of the electrolytic cell B due to the electrochemical reaction reaches a preset electrolysis target amount, the electrolytic cathode of the electrolytic cell B is removed from the electrolytic cell B.

2. The method for recycling circuit board acid etching waste liquid by progressive electrolysis according to claim 1, characterized in that: The anolyte of the electrolytic cell A contains at least one of an etching working solution, an etching waste solution, and a cathode electrolyte of the electrolytic cell B after electrolytic treatment; the anolyte of the electrolytic cell B contains at least one of an etching working solution, an etching waste solution, and an etching waste solution of the electrolytic cell B after electrolytic treatment.

3. The method for recycling circuit board acid etching waste liquid by progressive electrolysis according to claim 1, characterized in that: According to the redox potential value of the cathode electrolyte in the cathode tank area of ​​electrolytic cell A, the output current of the electrolytic power supply of electrolytic cell A is adjusted or started and shut down according to the process requirements, and / or a solution containing acidic etching waste liquid is added to the cathode tank area of ​​electrolytic cell A to maintain the concentration of the copper corrosive agent in its cathode electrolyte so that less metallic copper is electrolytically deposited on the electrolytic cathode or even no metallic copper is electrolytically deposited, and the main electrochemical reduction reaction is performed to reduce the concentration of the copper corrosive agent CuCl2, or CuCl2 and FeCl3 in the cathode electrolyte of electrolytic cell A or even eliminate its copper corrosive ability.

4. The method for recycling circuit board acid etching waste liquid by progressive electrolysis according to claim 1, characterized in that: During the electrolysis process, the oxidation-reduction potential value of the cathode electrolyte of the electrolytic cell A is controlled within a range of 200 to 580 mV, that is, the oxidation-reduction potential value (ORP) value of the external waste liquid is controlled within a range of 200 to 580 mV.

5. The method for recycling circuit board acid etching waste liquid by progressive electrolysis according to claim 1, characterized in that: At least one electrolytic cell C is added after the electrolytic cell B, wherein the electrolytic cell C is divided into an anode cell area and a cathode cell area; during electrolysis operation, an electrolytic anode and an electrolytic cathode are respectively provided in the anode cell area and the cathode cell area of ​​the electrolytic cell C, and electrolysis operation is performed on the anolyte and the catholyte respectively; The anolyte of the electrolytic cell C comprises at least one of an acidic etching working solution, the catholyte of the electrolytic cell B after electrolysis treatment, and the catholyte of the electrolytic cell C after electrolysis treatment, or further comprises etching waste liquid on this basis; the catholyte of the electrolytic cell C comprises the catholyte of the electrolytic cell B after electrolysis treatment, or further comprises the catholyte of the electrolytic cell A and / or etching waste liquid on this basis.

6. The method for recycling circuit board acid etching waste liquid by progressive electrolysis according to claim 5, characterized in that: The copper ion concentration of the electrolytic cathode of the electrolytic cell B and the cathode electrolyte of the electrolytic cell C is controlled to be no less than 5 g / L.

7. The method for recycling circuit board acid etching waste liquid by progressive electrolysis according to claim 5, characterized in that: The parameter value of at least one electrolyte in the method is detected, and the data measured on site is used as a basis to control the output current size and / or start and stop of the electrolytic power supply of electrolytic cell A and / or the electrolytic power supply of electrolytic cell B and / or the electrolytic power supply of electrolytic cell C, and / or control the addition of various materials. The parameter values ​​detected include but are not limited to any one or more of acidity value, specific gravity value, redox potential value, photoelectric colorimetric value, liquid level, temperature, flow rate, and harmful gas concentration.

8. The method for recycling circuit board acid etching waste liquid by progressive electrolysis according to claim 5, characterized in that: The anolyte of electrolytic cell A and / or the anolyte of electrolytic cell B and / or the anolyte of electrolytic cell C in the electrolytic cell with electrolytic separator are circulated and mixed with the etching working solution on the etching production line, so that the etching working solution on the etching production line can be supplemented with copper etching agent online.

9. A device for recycling circuit board acid etching waste liquid using the progressive electrolysis method according to any one of claims 1 to 8, characterized in that: include: At least one electrolytic cell A and at least one electrolytic cell B are used. The interior of the electrolytic cell A is separated by an electrolytic cell separator into an anode cell area and a cathode cell area, and the interior of the electrolytic cell B is divided into an anode cell area and a cathode cell area. A redox potentiometer is installed in the cathode cell area of ​​the electrolytic cell A. The cathode cell area of ​​the electrolytic cell A and the cathode cell area of ​​the electrolytic cell B are connected by a liquid flow pipeline. The solution that has undergone electrolysis reaction in the cathode cell area of ​​the electrolytic cell A is added to the cathode cell area of ​​the electrolytic cell B for progressive electrolysis to extract copper. The anode cell area of ​​the electrolytic cell A and the cathode cell area of ​​the electrolytic cell A are respectively provided with an electrolysis anode and an electrolysis cathode, and the electrolysis anode and the electrolysis cathode are respectively connected to the positive electrode and the negative electrode of the electrolysis power supply of the electrolytic cell A. The anode cell area of ​​the electrolytic cell B and the cathode cell area of ​​the electrolytic cell B are respectively provided with an electrolysis anode and an electrolysis cathode of the electrolytic cell B, and the electrolysis anode and the electrolysis cathode are respectively connected to the positive electrode and the negative electrode of the electrolysis power supply of the electrolytic cell B.

10. The device according to claim 1, characterized in that: At least one electrolytic cell C is added after the electrolytic cell B, wherein the electrolytic cell C is divided into an anode cell area and a cathode cell area; the cathode cell area of ​​the electrolytic cell B is connected to the cathode cell area of ​​the electrolytic cell C through a liquid flow pipeline, and the solution after electrolysis treatment in the cathode cell area of ​​the electrolytic cell B is added to the cathode cell area of ​​the electrolytic cell C; the anode cell area of ​​the electrolytic cell C and the cathode cell area of ​​the electrolytic cell C are respectively provided with an electrolytic anode and an electrolytic cathode, and the electrolytic anode and the electrolytic cathode are respectively connected to the positive electrode and the negative electrode of the electrolytic power supply C; during the electrolysis process, the electrolytic cell C The anode tank area and cathode tank area are respectively filled with anolyte and catholyte; the anolyte of electrolytic cell C contains at least one of an etching working solution, the catholyte of electrolytic cell B after electrolysis treatment, and the catholyte of electrolytic cell C after electrolysis treatment, or further contains etching waste liquid on this basis; the catholyte of electrolytic cell C contains the catholyte of electrolytic cell B after electrolysis treatment, or further contains the catholyte of electrolytic cell A and / or etching waste liquid on this basis.

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