Chlorine-free acid etching liquid recovery method and device

Abstract

The invention discloses a chlorine-free acid etching liquid recovery method and device. The acid etching liquid recovery device comprises an electrolytic tank, a negative electrode liquid transfer tank and an overflow collecting tank, an ionic membrane is arranged in the middle of the electrolytic cell and divides the electrolytic cell into a positive electrode chamber and a negative electrode chamber. According to the acid etching liquid recycling method, through the circulation mode of the positive electrode chamber and the etching machine, the positive electrode chamber is used for increasing the ORP value of the waste etching liquid, the waste etching liquid is regenerated into the etching liquid, the etching machine is used for reducing the ORP value of the etching liquid, and the etching liquid is recycled. The recycling of the strong acid etching waste liquid is realized. The positive electrode liquid contains Fe < 2 + > ions, so that the generation of chlorine is inhibited, the reutilization of the etching liquid and the recovery of Cu < 2 + > ions are realized, the circulating flow between the etching machine and the positive electrode chamber is reduced, and the addition amount of an oxidizing agent and hydrochloric acid is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of recycling and treating waste etching liquid, and in particular to a method and a device for recycling acidic etching liquid without generating chlorine gas. Background Art

[0002] Copper etching is a crucial step in the production and manufacturing of PCB circuit boards. At present, the etching solutions used in the etching process are mainly acidic and alkaline etching solutions. After the etching is completed, a large amount of etching waste liquid will be generated. The etching solution contains a large amount of copper ions, acid, alkali, and ammonia nitrogen, which will cause damage to the environment. It is very important to recycle the etching waste liquid.

[0003] In the copper recovery process of acid etching solution, the etching solution is separated into the positive electrode chamber and the negative electrode chamber by an ion membrane. The electrolyte in the negative electrode chamber has a lower ORP value due to the reduction effect of the negative electrode, and finally the negative electrode electrolyzes the metallic copper. In the positive electrode chamber, the electrolyte has an oxidation-reduction potential, or ORP value, due to the oxidation effect of the positive electrode. The anode will produce a chlorine reaction and precipitate a large amount of chlorine. Chlorine can irritate the respiratory system, eyes and skin, which can be life-threatening in severe cases, and there are certain safety hazards. Moreover, chlorine is corrosive in the environment, which can cause harm to plants and aquatic organisms, affect the ecological balance, and cause secondary pollution. Summary of the invention

[0004] The purpose of the present invention is to provide a method and device for recovering an acidic etching solution without generating chlorine gas, so as to solve the problem that a large amount of chlorine gas will be precipitated from the anode in the existing acidic etching solution copper recovery process, causing secondary pollution.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] The present invention provides an acid etching liquid recovery device without generating chlorine gas, which is applied to an etcher, and comprises an electrolytic cell, a cathode liquid transfer tank and an overflow collection tank; an ion membrane is arranged in the middle of the electrolytic cell, and the ion membrane separates the electrolytic cell into a cathode chamber and a cathode chamber, a positive electrode is arranged in the cathode chamber, and a negative electrode is arranged in the cathode chamber; the cathode chamber is filled with cathode liquid; the cathode chamber is filled with cathode liquid; the etching liquid in the etcher contains trivalent iron ions, and the cathode liquid contains divalent iron ions;

[0007] The cathode chamber is provided with an etching waste liquid inlet, a cathode liquid outlet and a cathode liquid replenishing port, the etching waste liquid inlet is connected to the etching waste liquid outlet of the etcher through an etching waste liquid pipeline, and the cathode liquid outlet is connected to the cathode liquid inlet of the etcher through the cathode liquid pipeline;

[0008] The negative electrode chamber is provided with a negative electrode liquid inlet and a negative electrode liquid outlet; the negative electrode liquid transfer tank is provided with a negative electrode chamber output port, a positive electrode chamber output port, a negative electrode liquid circulation inlet and an overflow input port; the overflow collecting tank is provided with an overflow input port and an overflow output port;

[0009] The negative electrode liquid inlet is connected to the negative electrode chamber output port through the first negative electrode pipeline; the negative electrode liquid outlet is connected to the negative electrode liquid circulation inlet through the second negative electrode pipeline; the positive electrode chamber output port is connected to the positive electrode liquid replenishment port through the positive electrode liquid replenishment pipe;

[0010] The overflow input port is communicated with the overflow outlet of the etching machine through a first overflow pipe, and the overflow output port is communicated with the overflow input port through a second overflow pipe.

[0011] In the acidic etching solution recovery device without generating chlorine gas, a cathode solution transfer tank and a first conveying device are provided in the cathode solution pipeline, and the first conveying device is arranged at one side of the output port of the cathode solution transfer tank.

[0012] In the acidic etching liquid recovery device without chlorine gas generation, the negative electrode liquid transfer tank includes a negative electrode liquid circulation tank and a negative electrode liquid collecting tank; the negative electrode chamber output port, the negative electrode liquid circulation inlet port and the overflow input port are all arranged in the negative electrode liquid circulation tank, the positive electrode chamber output port is arranged in the negative electrode liquid collecting tank, and the negative electrode liquid circulation tank and the negative electrode liquid collecting tank are connected through a negative electrode liquid collecting pipe.

[0013] In the acidic etching liquid recovery device without generating chlorine gas, a second conveying device is provided in the etching waste liquid pipeline, and the second conveying device conveys the etching waste liquid in the etcher to the positive electrode chamber;

[0014] A third conveying device is provided in the first negative electrode pipeline, and the third conveying device conveys the negative electrode liquid in the negative electrode liquid transfer tank to the negative electrode chamber;

[0015] The cathode liquid replenishing pipe is provided with a fourth conveying device, and the fourth conveying device conveys the cathode liquid in the cathode liquid transfer tank to the cathode chamber;

[0016] The second overflow pipeline is provided with a fifth conveying device, and the fifth conveying device conveys the etching waste liquid in the overflow collection tank to the cathode liquid transfer tank.

[0017] The present invention also provides a method for recovering an acidic etching solution without generating chlorine gas, and the method uses the above-mentioned acidic etching solution recovery device, comprising the following steps:

[0018] Prepare an etching solution, add trivalent iron salt into the etching solution, and then input the etching solution into the etcher;

[0019] Prepare positive electrode solution and negative electrode solution, and input the positive electrode solution into the positive electrode chamber, and input the negative electrode solution into the negative electrode chamber and the negative electrode solution transfer tank;

[0020] Starting the etcher and the electrolytic cell, so that the etcher performs etching and the electrolytic cell performs electrolysis;

[0021] The etching waste liquid in the etcher is transported to the cathode chamber through the etching waste liquid pipeline for electrolysis, and the cathode liquid is transported to the etcher through the cathode liquid pipeline, so that the etching waste liquid and the cathode liquid circulate between the etcher and the cathode chamber respectively;

[0022] Detecting the copper ion concentration of the etching waste liquid in the etcher, and when the copper ion concentration of the etching waste liquid is higher than a predetermined value, transporting the cathode liquid in the cathode liquid transfer tank to the cathode chamber;

[0023] The copper ion concentration of the cathode liquid in the cathode chamber is detected. When the copper ion concentration of the cathode liquid is lower than a predetermined value, the etching waste liquid in the overflow collection tank is transported to the cathode liquid transfer tank, and the cathode liquid is circulated between the cathode liquid transfer tank and the cathode chamber.

[0024] In the method for recovering an acidic etching solution without generating chlorine gas, in the cathode solution, Cu 2+ The concentration of ions is 120-140 g / L, Fe 3+ The concentration of ions is 30-40 g / L, Cl - The concentration of ions is 270-300 g / L; the acidity of the cathode solution is 1.2-2.5, and the ORP value of the cathode solution is 650-750 mv; the ORP value of the etching solution in the etcher is 450-600 mv;

[0025] In the negative electrode solution, Cu 2+ The concentration of ions is 30-40 g / L, Fe 3+ The concentration of ions is 30-40 g / L, Cl - The concentration of ions is 180-230 g / L, and the acidity of the negative electrode solution is 2.5-4.0.

[0026] In the method for recovering an acidic etching solution without generating chlorine, the Cu 2+ The predetermined value of the ion concentration is 140 g / L; the Cu 2+ The predetermined value of the ion concentration is 30 g / L.

[0027] In the method for recovering an acidic etching solution without generating chlorine gas, the trivalent iron salt is ferric chloride.

[0028] In the method for recovering the acidic etching solution without generating chlorine, the current density of the electrolysis in the electrolytic cell is 100 to 400 A / m 2 .

[0029] A technical solution in the present invention can have the following beneficial effects:

[0030] The acid etching liquid recovery method uses the circulation mode of the cathode chamber and the etcher to increase the ORP value of the etching waste liquid by using the cathode chamber to regenerate the etching waste liquid into etching liquid, and uses the etcher to reduce the ORP value in the etching liquid, thereby realizing the recycling and reuse of the strong acid etching waste liquid. 2+ ions, suppressing the generation of chlorine gas, achieving the recycling of etching solution and Cu 2+ Ion recovery and the circulation flow between the etcher and the cathode chamber are reduced, reducing the amount of oxidant and hydrochloric acid added. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural schematic diagram of one embodiment of the present invention;

[0032] In the attached drawings: an etcher 1, an electrolytic cell 2, a cathode liquid transfer tank 3, and an overflow collection tank 4;

[0033] Ion membrane 21, cathode chamber 22, cathode chamber 23; cathode liquid circulation tank 31, cathode liquid collection tank 32;

[0034] Etching waste liquid pipeline 101, cathode liquid pipeline 102, first cathode pipeline 103, second cathode pipeline 104, cathode liquid replenishing pipe 105, first overflow pipe 106, second overflow pipe 107; cathode liquid collecting pipe 108; second conveying device 111; cathode liquid transfer tank 121, first conveying device 122; third conveying device 131; fourth conveying device 151; fifth conveying device 161. DETAILED DESCRIPTION

[0035] The technical scheme of the present invention is further illustrated by specific embodiments below. In order to facilitate understanding of the present invention, the present invention is described more comprehensively below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0036] If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the field or the product instructions are used. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0038] Please refer to Figure 1 The present invention provides an acid etching liquid recovery device without generating chlorine gas, which is applied to an etcher 1, and comprises an electrolytic cell 2, a cathode liquid transfer tank 3 and an overflow collection tank 4; an ion membrane 21 is arranged in the middle of the electrolytic cell 2, and the ion membrane 21 separates the electrolytic cell 2 into a cathode chamber 22 and a cathode chamber 23, a positive electrode is arranged in the cathode chamber 22, and a negative electrode is arranged in the cathode chamber 23; the cathode chamber 22 is filled with cathode liquid; the cathode chamber 23 is filled with cathode liquid; the etching liquid in the etcher 1 contains trivalent iron ions, and the cathode liquid contains divalent iron ions;

[0039] The cathode chamber 22 is provided with an etching waste liquid inlet, a cathode liquid outlet and a cathode liquid replenishing port, the etching waste liquid inlet is connected to the etching waste liquid outlet of the etcher through an etching waste liquid pipeline 101, and the cathode liquid outlet is connected to the cathode liquid inlet of the etcher through a cathode liquid pipeline 102;

[0040] The negative electrode chamber 23 is provided with a negative electrode liquid inlet and a negative electrode liquid outlet; the negative electrode liquid transfer tank 3 is provided with a negative electrode chamber output port, a positive electrode chamber output port, a negative electrode liquid circulation inlet and an overflow input port; the overflow collecting tank 4 is provided with an overflow input port and an overflow output port;

[0041] The negative electrode liquid inlet is connected to the negative electrode chamber output port through the first negative electrode pipe 103; the negative electrode liquid outlet is connected to the negative electrode liquid circulation inlet through the second negative electrode pipe 104; the positive electrode chamber output port is connected to the positive electrode liquid replenishment port through the positive electrode liquid replenishment pipe 105;

[0042] The overflow input port is communicated with the overflow outlet of the etching machine through the first overflow pipe 106 , and the overflow output port is communicated with the overflow input port through the second overflow pipe 107 .

[0043] The cathode solution contains divalent iron ions, so the chemical reactions occurring in the cathode chamber 22 include:

[0044] Cu + -e - =Cu 2+ ;

[0045] Fe 2+ -e - =Fe 3+ ;

[0046] Cu + +Fe 3+ =Cu 2+ +Fe 2+ ;

[0047] 2Cl - -2e - =Cl2 ;

[0048] Cl 2 +2Fe 2+ =2Cl - +Fe 3+ ;

[0049] The chemical reactions occurring in the cathode chamber 23 include:

[0050] Cu 2+ +2e - =Cu.

[0051] Due to Cu + / Cu 2+ The standard electrode potential of 298.15K is -0.159V, Fe 2+ / Fe 3+ The standard electrode potential of 298.15K is -0.771V, Cl - / Cl 2 The standard electrode potential of 298.15K is -1.3583V. The order of chemical reaction between copper ions, iron ions, and chloride ions in the positive electrode tank and the positive electrode is: Cu + -e - =Cu 2+ , Fe 2+ -e - =Fe 3+ , 2Cl - -2e - =Cl 2 .

[0052] Therefore, when there is a certain concentration of Fe in the cathode solution 2+ When Cu + -e - =Cu 2+ , and Fe 2+ -e - =Fe 3+ The reaction will reduce 2Cl - -2e - =Cl 2 The reaction takes place, so that the amount of chlorine precipitated is extremely small, which can be treated by the tail gas treatment device.

[0053] The acid etching solution recovery device is provided with an electrolytic cell 2, a cathode liquid transfer tank 3 and an overflow collection tank 4. The electrolytic cell 2 includes a cathode chamber 22 and a cathode chamber 23. The cathode chamber 22 and the etcher 1 are interconnected through a pipeline, so that the etching waste liquid generated by the etcher 1 enters the cathode chamber 22, and the cathode liquid in the cathode chamber 22 enters the etcher 1, so that the etching waste liquid and the cathode liquid are circulated between the etcher 1 and the cathode chamber 22 respectively.+ The ions are oxidized to high-valent Cu under the action of the positive electrode. 2+ ions to restore the oxidation performance of the solution, improve the ORP value of the etching waste liquid, regenerate the etching waste liquid into etching liquid, and re-input it into the etcher 1 for reuse, thus realizing the recycling and reuse of the strong acid etching waste liquid. 2+ Ions enter the negative electrode chamber 23 through the ion membrane 21 and are pumped into the cathode region of the electrode containing Cu 2+ The dilute solution of ions is continuously circulated. Under the action of the electrodes, Cu 2+ The ions are reduced to powdered high-purity metals, which are separated by a copper powder separator to recover heavy metal resources.

[0054] The cathode liquid transfer tank 3 is connected to the cathode chamber 22 through the cathode liquid replenishing pipe 105. When the etching liquid in the etching machine etches the copper metal of the PCB board, Cu 2+ When the ion concentration increases and exceeds the set value, the low-copper cathode liquid in the cathode liquid transfer tank 3 is transported to the cathode chamber 22; then, the liquid level of the etcher 1 rises accordingly, and the etching waste liquid rich in copper ions is replenished to the overflow collection tank 4 through the first overflow pipe 106. 2+ Too high ion concentration affects the efficiency of the chemical reaction occurring in the cathode chamber 22 .

[0055] The cathode liquid transfer tank 3 is connected to the cathode chamber 23 through a pipeline, so that the cathode liquid can circulate between the cathode liquid transfer tank 3 and the cathode chamber 23. Since the overflow collection tank 4 stores the excess etching waste liquid rich in copper ions in the etcher 1, the Cu in the cathode liquid 2+ After electrodeposition, Cu 2+ The ion concentration is reduced, and the Cu-rich electrolyte can be transported to the cathode liquid transfer tank 3 through the second overflow pipe 107. 2+ The etching waste liquid of the ions is then replenished to the negative electrode chamber 23 through the negative electrode liquid transfer tank 3. 2+ ion.

[0056] Specifically, a cathode solution transfer tank 121 and a first conveying device 122 are provided in the cathode solution pipeline 102 . The first conveying device 122 is disposed at one side of the output port of the cathode solution transfer tank 121 .

[0057] With the above structure, the cathode liquid transfer tank 121 can temporarily store the cathode liquid, and when the etcher 1 needs to be supplemented with a high ORP solution, it is then transported through the first transport device 122. The cathode liquid transfer tank 121 acts as a buffer to balance the inflow and outflow of solutions, and can effectively adjust the pressure and flow rate of the system to avoid overload or fluctuation.

[0058] Specifically, the negative electrode liquid transfer tank 3 includes a negative electrode liquid circulation tank 31 and a negative electrode liquid collecting tank 32; the negative electrode chamber output port, the negative electrode liquid circulation inlet port and the overflow input port are all arranged in the negative electrode liquid circulation tank 31, and the positive electrode chamber output port is arranged in the negative electrode liquid collecting tank 32, and the negative electrode liquid circulation tank 31 and the negative electrode liquid collecting tank 32 are connected through the negative electrode liquid collecting pipe 108.

[0059] The cathode liquid circulation tank 31 is used for cathode liquid circulation and receiving etching waste liquid rich in copper ions transported from the overflow collection tank 4. The cathode liquid circulation tank 31 replenishes cathode liquid to the cathode chamber 23 through the first cathode pipe 103, and the cathode chamber 23 inputs excess cathode liquid to the cathode liquid circulation tank 31 through the second cathode pipe 104 to realize the circulation of cathode liquid, so as to control the Cu ion content in the cathode liquid. 2+ Ion content.

[0060] The cathode liquid collection tank 32 is used to collect the lower Cu 2+ ion content of the negative electrode solution, when the Cu 2+ When the ion content is too high, the negative electrode liquid collection tank 32 will be lower Cu 2+ The negative electrode liquid with the ion content is transported to the positive electrode chamber 22 to adjust the Cu 2+ The content of ions.

[0061] Specifically, the etching waste liquid pipeline 101 is provided with a second conveying device 111, and the second conveying device 111 conveys the etching waste liquid in the etcher to the cathode chamber 22;

[0062] The first negative electrode pipeline 103 is provided with a third conveying device 131, and the third conveying device 131 conveys the negative electrode liquid in the negative electrode liquid transfer tank 3 to the negative electrode chamber 23;

[0063] The cathode liquid replenishing pipe 105 is provided with a fourth conveying device 151, and the fourth conveying device 151 conveys the cathode liquid in the cathode liquid transfer tank 3 to the cathode chamber 22;

[0064] The second overflow pipe 107 is provided with a fifth conveying device 161 , and the fifth conveying device 161 conveys the etching waste liquid in the overflow collecting tank 4 to the cathode liquid transfer tank 3 .

[0065] In a specific embodiment of the present invention, the first conveying device 122, the second conveying device 111, the third conveying device 131, the fourth conveying device 151 and the fifth conveying device 161 are all infusion pumps. By adjusting the first conveying device 122, the second conveying device 111, the third conveying device 131, the fourth conveying device 151 and the fifth conveying device 161, the Cu between the positive electrode chamber 22, the negative electrode chamber 23 and the etcher 1 is adjusted. 2+ Ions and Cu +Ion content, so that the etching solution can be reused and Cu 2+ Ion recovery.

[0066] The present invention provides a method for recovering an acidic etching liquid without generating chlorine gas, and the method uses the above-mentioned acidic etching liquid recovery device, comprising the following steps:

[0067] Prepare an etching solution, add trivalent iron salt into the etching solution, and then input the etching solution into the etcher 1;

[0068] Prepare positive electrode liquid and negative electrode liquid, and input the positive electrode liquid into the positive electrode chamber 22, and input the negative electrode liquid into the negative electrode chamber 23 and the negative electrode liquid transfer tank 3;

[0069] Start the etcher 1 and the electrolytic cell 2, so that the etcher 1 performs etching and the electrolytic cell 2 performs electrolysis;

[0070] The etching waste liquid in the etcher 1 is transported to the cathode chamber 22 through the etching waste liquid pipeline 101 for electrolysis, and the cathode solution is transported to the etcher 1 through the cathode solution pipeline 102, so that the etching waste liquid and the cathode solution are circulated between the etcher 1 and the cathode chamber 22 respectively;

[0071] Detecting the copper ion concentration of the etching waste liquid in the etcher 1, and when the copper ion concentration of the etching waste liquid is higher than a predetermined value, transporting the cathode liquid in the cathode liquid transfer tank 3 to the cathode chamber 22;

[0072] The copper ion concentration of the cathode liquid in the cathode chamber 23 is detected. When the copper ion concentration of the cathode liquid is lower than a predetermined value, the etching waste liquid in the overflow collection tank 4 is transported to the cathode liquid transfer tank 3, and the cathode liquid is circulated between the cathode liquid transfer tank 3 and the cathode chamber 23.

[0073] Under the same copper metal content, Cu + The higher the ion content, the slower the etching rate. Therefore, in the prior art, it is necessary to increase the circulation flow between the positive electrode tank and the etching tank to reduce the Cu + The influence of Fe ions on the etching rate. In the solution described in the present invention, Fe 3+ Ions will react with Cu + Ion reaction produces Fe 2+ Ions and Cu 2+ ions, that is, as long as there is a certain amount of Fe 3+ The presence of ions will reduce the Cu content in the etching solution. + ratio, equivalent to Fe 2+ ions to replace Cu + The ions circulate between the cathode chamber and the etching tank, so that the etching rate will not decrease even at a lower circulation flow rate. Therefore, there is a certain amount of Fe in the etching solution. 2+ ions, which can reduce the Cu +ions, therefore, there is no need to increase the circulation flow between the positive electrode tank and the etching tank, and the circulation flow between the positive electrode tank and the etching tank can be reduced.

[0074] When the etching machine is working, Cu is consumed during etching. 2+ ions, producing Cu + ions, resulting in a decrease in the ORP value. In the prior art, when the ORP value is lower than the set value, the etching machine automatically adds oxidants and hydrochloric acid to increase the ORP value. In this solution, since there is a certain concentration of Fe in the cathode solution, 2+ The presence of ions inhibits the precipitation of chlorine at the positive electrode. Therefore, it is only necessary to maintain a faster cycle between the positive electrode tank and the etching machine to avoid the precipitation of a large amount of chlorine at the positive electrode, reduce the number of times the etching machine uses oxidants and hydrochloric acid, and avoid the problem of excessive ORP value and chlorine precipitation caused by excessive addition of sodium chlorate and hydrochloric acid. In a specific embodiment, the oxidant is sodium chlorate.

[0075] The acid etching liquid recovery method uses the circulation mode of the cathode chamber 22 and the etcher 1, uses the cathode chamber 22 to increase the ORP value of the etching waste liquid, regenerates the etching waste liquid into etching liquid, and uses the etcher 1 to reduce the ORP value in the etching liquid, thereby realizing the recycling and regeneration of the strong acid etching waste liquid. 2+ ions, suppressing the generation of chlorine gas, achieving the recycling of etching solution and Cu 2+ Ions are recovered and the circulation flow between the etcher 1 and the cathode chamber 22 is reduced, thereby reducing the amount of oxidant and hydrochloric acid added.

[0076] Specifically, in the cathode solution, Cu 2+ The concentration of ions is 120-140 g / L, Fe 3+ The concentration of ions is 30-40 g / L, Cl - The concentration of ions is 270-300 g / L; the acidity of the cathode solution is 1.2-2.5, and the ORP value of the cathode solution is 650-750 mv; the ORP value of the etching solution in the etcher 1 is 450-600 mv;

[0077] In the negative electrode solution, Cu 2+ The concentration of ions is 30-40 g / L, Fe 3+ The concentration of ions is 30-40 g / L, Cl - The concentration of ions is 180-230 g / L, and the acidity of the negative electrode solution is 2.5-4.0.

[0078] ORP value can reflect the Cu content in the cathode solution. + Ions and Fe 2+Ion concentration, by controlling the ORP value to maintain at 650 ~ 750mv, can ensure that the amount of positive electrode chlorine precipitation during electrolysis is extremely small. Acidity affects the etching speed of the etching solution. The above acidity can increase the etching speed.

[0079] Specifically, the Cu of the etching waste liquid 2+ The predetermined value of the ion concentration is 140 g / L; the Cu 2+ The predetermined value of the ion concentration is 30 g / L.

[0080] Since the Cu 2+ The concentration of ions is 120-140 g / L, and the Cu 2+ The concentration of ions is 30-40 g / L. 2+ When the predetermined value of ion concentration is higher than 140g / L, it is necessary to input Cu 2+ The negative electrode solution with low ion content balances the Cu 2+ ion concentration; similarly, the Cu 2+ The predetermined value of ion concentration is lower than 30g / L, and it is necessary to supplement with Cu-rich 2+ Ion etching waste liquid.

[0081] Specifically, the trivalent iron salt is ferric chloride. In a specific embodiment of the present invention, ferric chloride is used as the etching solution to supplement Fe 3+ Ions, after ferric chloride dissolves, produce Fe 3+ Ions and Cl - ions, avoiding the introduction of other ions, thereby preventing other ions from interfering with the electrolysis or etching reaction.

[0082] Specifically, the current density of the electrolysis in the electrolytic cell 2 is 100-400 A / m 2 .

[0083] In a specific embodiment of the invention, the circulation flow rate between the etcher 1 and the cathode chamber 22 is 550-650 L / h.

[0084] The circulation flow is set according to the scale of the electrolysis equipment, but the electrolysis current density is controlled by the PLC controller according to the cathode liquid ORP value as a signal, so as to achieve the purpose of stabilizing the etching solution ORP value in a certain range. Therefore, during the operation of the equipment, the circulation flow is stable and the current density will change, ranging from 100 to 400A / m 2 .

[0085] Example Group A

[0086] A method for recovering an acidic etching solution without generating chlorine gas comprises the following steps:

[0087] Prepare an etching solution, add ferric chloride into the etching solution, and then input the etching solution into the etcher 1;

[0088] Prepare positive electrode liquid and negative electrode liquid, and input the positive electrode liquid into the positive electrode chamber 22, and input the negative electrode liquid into the negative electrode chamber 23 and the negative electrode liquid transfer tank 3;

[0089] Start the etcher 1 and the electrolytic cell 2, so that the etcher 1 performs etching and the electrolytic cell 2 performs electrolysis;

[0090] The etching waste liquid in the etcher 1 is transported to the cathode chamber 22 through the etching waste liquid pipeline 101 for electrolysis, and the cathode liquid is transported to the etcher 1 through the cathode liquid pipeline 102, so that the etching waste liquid and the cathode liquid are circulated between the etcher 1 and the cathode chamber 22 respectively, and the circulation flow rate is 600L / h;

[0091] Detecting the copper ion concentration of the etching waste liquid in the etcher 1, and when the copper ion concentration of the etching waste liquid is higher than a predetermined value, transporting the cathode liquid in the cathode liquid transfer tank 3 to the cathode chamber 22;

[0092] The copper ion concentration of the cathode liquid in the cathode chamber 23 is detected. When the copper ion concentration of the cathode liquid is lower than a predetermined value, the etching waste liquid in the overflow collection tank 4 is transported to the cathode liquid transfer tank 3, and the cathode liquid is circulated between the cathode liquid transfer tank 3 and the cathode chamber 23.

[0093] Wherein, in the cathode solution, Cu 2+ The concentration of ions is 121g / L, Fe 3+ The concentration of ions is 36g / L, Cl - The concentration of ions is 294 g / L; the acidity of the cathode solution is 1.6.

[0094] In the negative electrode solution, Cu 2+ The concentration of ions is 35g / L, Fe 3+ The concentration of ions is 35g / L, Cl - The concentration of ions is 210 g / L, and the acidity of the cathode solution is 2.8.

[0095] Table 1-Specific parameters of each embodiment of embodiment group A

[0096] Etching solution ORP value (mv) Cathode liquid ORP value (mv) <![CDATA[Current density (A / m 2 )]]> Example 1 600 700 200～400 Example 2 500 600 150～350 Example 3 450 500 100～300

[0097] The chlorine gas detection was carried out on the etching machine and the positive electrode tank in Examples 1, 2 and 3. The results are shown in Table 2.

[0098] Table 2 - Chlorine gas detection results of Example Group A

[0099] Chlorine gas content in etching machine (ppm) Chlorine gas content in positive electrode tank (ppm) Example 1 65 1200 Example 2 10 110 Example 3 0.2 24

[0100] According to the results in Table 2, high current density can increase the speed of the electrolysis process and reduce production time. However, too high current density may cause the electrolytic cell to react too quickly, resulting in incomplete reactions or undesirable side reactions. For example, too high current density may cause a higher proportion of chlorine evolution reactions.

[0101] Example Group B

[0102] The steps of Example Group B are the same as those of Example Group A, except that the positive electrode solution and the negative electrode solution are different from those of Example Group A.

[0103] In the cathode solution, Cu 2+ The concentration of ions is 121g / L, Fe 3+ The concentration of ions is 0g / L, Cl - The concentration of ions is 245 g / L; the acidity of the cathode solution is 1.8N.

[0104] In the negative electrode solution, Cu 2+ The concentration of ions is 35g / L, Fe 3+ The concentration of ions is 0g / L, Cl - The concentration of ions is 183 g / L, and the acidity of the cathode solution is 3.0N.

[0105] Table 3-Specific parameters of each embodiment of embodiment group B

[0106] Etching solution ORP value (mv) Cathode liquid ORP value (mv) <![CDATA[Current density (A / m 2 )]]> Example 4 700 558 200～400 Example 5 600 465 150～350 Example 6 500 390 100～300

[0107] Chlorine gas detection was performed on the etching machine and the positive electrode tank in Examples 4, 5, and 6. The results are shown in Table 4.

[0108] Table 4 - Chlorine gas detection results of Example Group B

[0109] Chlorine gas content in etching machine (ppm) Chlorine gas content in positive electrode tank (ppm) Example 4 31 1420 Example 5 10 110 Example 6 0.2 24

[0110] According to the results of Table 2 and Table 4, the etching solution orp value can be controlled to be stable within a certain range by monitoring the cathodic solution orp value to work for the etching machine, and only a very small amount of chlorine will be produced during the electrolysis process. By comparing Example 1 and Example 4, it can be seen that the two embodiments only have different iron ion contents in the cathode solution and the cathode solution (35g / L in Example 1 and 0g / L in Example 4), and the rest are the same. In Example 1, where iron ions are added, the etching solution orp value is higher and the etching ability is stronger.

[0111] The technical principle of the present invention is described above in conjunction with specific embodiments. These descriptions are only for explaining the principle of the present invention and cannot be interpreted as limiting the scope of protection of the present invention in any way. Based on the explanations herein, those skilled in the art can associate other specific embodiments of the present invention without creative work, and these equivalent variations or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A chlorine-free acidic etching liquid recovery device, applied to an etching machine, characterized in that: It comprises an electrolytic cell, a cathode liquid transfer tank and an overflow collection tank; an ion membrane is arranged in the middle of the electrolytic cell, and the ion membrane separates the electrolytic cell into a cathode chamber and a cathode chamber, a positive electrode is arranged in the cathode chamber, and a negative electrode is arranged in the cathode chamber; the cathode chamber is filled with cathode liquid; the cathode chamber is filled with cathode liquid; the etching liquid in the etcher contains trivalent iron ions, and the cathode liquid contains divalent iron ions; The cathode chamber is provided with an etching waste liquid inlet, a cathode liquid outlet and a cathode liquid replenishing port, the etching waste liquid inlet is connected to the etching waste liquid outlet of the etcher through an etching waste liquid pipeline, and the cathode liquid outlet is connected to the cathode liquid inlet of the etcher through the cathode liquid pipeline; The negative electrode chamber is provided with a negative electrode liquid inlet and a negative electrode liquid outlet; the negative electrode liquid transfer tank is provided with a negative electrode chamber output port, a positive electrode chamber output port, a negative electrode liquid circulation inlet and an overflow input port; the overflow collecting tank is provided with an overflow input port and an overflow output port; The negative electrode liquid inlet is connected to the negative electrode chamber output port through the first negative electrode pipeline; the negative electrode liquid outlet is connected to the negative electrode liquid circulation inlet through the second negative electrode pipeline; the positive electrode chamber output port is connected to the positive electrode liquid replenishment port through the positive electrode liquid replenishment pipe; The overflow input port is communicated with the overflow outlet of the etching machine through a first overflow pipe, and the overflow output port is communicated with the overflow input port through a second overflow pipe.

2. The acidic etching liquid recovery device without chlorine generation according to claim 1, characterized in that: The cathode liquid pipeline is provided with a cathode liquid transfer tank and a first conveying device, and the first conveying device is arranged at one side of the output port of the cathode liquid transfer tank.

3. The acidic etching liquid recovery device without chlorine gas generation according to claim 1, characterized in that: The negative electrode liquid transfer tank includes a negative electrode liquid circulation tank and a negative electrode liquid collecting tank; the negative electrode chamber output port, the negative electrode liquid circulation inlet port and the overflow input port are all arranged in the negative electrode liquid circulation tank, the positive electrode chamber output port is arranged in the negative electrode liquid collecting tank, and the negative electrode liquid circulation tank and the negative electrode liquid collecting tank are connected through a negative electrode liquid collecting pipe.

4. The acid etching liquid recovery device without chlorine generation according to claim 1, characterized in that: A second conveying device is provided in the etching waste liquid pipeline, and the second conveying device conveys the etching waste liquid in the etcher to the positive electrode chamber; A third conveying device is provided in the first negative electrode pipeline, and the third conveying device conveys the negative electrode liquid in the negative electrode liquid transfer tank to the negative electrode chamber; The cathode liquid replenishing pipe is provided with a fourth conveying device, and the fourth conveying device conveys the cathode liquid in the cathode liquid transfer tank to the cathode chamber; The second overflow pipeline is provided with a fifth conveying device, and the fifth conveying device conveys the etching waste liquid in the overflow collection tank to the cathode liquid transfer tank.

5. A method for recovering an acidic etching solution without generating chlorine, characterized in that: The acid etching solution recovery device according to any one of claims 1 to 4 is used, comprising the following steps: Prepare an etching solution, add trivalent iron salt into the etching solution, and then input the etching solution into the etcher; Prepare positive electrode solution and negative electrode solution, and input the positive electrode solution into the positive electrode chamber, and input the negative electrode solution into the negative electrode chamber and the negative electrode solution transfer tank; Starting the etcher and the electrolytic cell, so that the etcher performs etching and the electrolytic cell performs electrolysis; The etching waste liquid in the etcher is transported to the cathode chamber through the etching waste liquid pipeline for electrolysis, and the cathode liquid is transported to the etcher through the cathode liquid pipeline, so that the etching waste liquid and the cathode liquid circulate between the etcher and the cathode chamber respectively; Detecting the copper ion concentration of the etching waste liquid in the etcher, and when the copper ion concentration of the etching waste liquid is higher than a predetermined value, transporting the cathode liquid in the cathode liquid transfer tank to the cathode chamber; The copper ion concentration of the cathode liquid in the cathode chamber is detected. When the copper ion concentration of the cathode liquid is lower than a predetermined value, the etching waste liquid in the overflow collection tank is transported to the cathode liquid transfer tank, and the cathode liquid is circulated between the cathode liquid transfer tank and the cathode chamber.

6. A method for recovering an acidic etching solution without generating chlorine according to claim 5, characterized in that: In the cathode solution, Cu 2+ The concentration of ions is 120-140 g / L, Fe 3+ The concentration of ions is 30-40 g / L, Cl - The concentration of ions is 270-300 g / L; the acidity of the cathode solution is 1.2-2.5, and the ORP value of the cathode solution is 650-750 mv; the ORP value of the etching solution in the etcher is 450-600 mv; In the negative electrode solution, Cu 2+ The concentration of ions is 30-40 g / L, Fe 3+ The concentration of ions is 30-40 g / L, Cl - The concentration of ions is 180-230 g / L, and the acidity of the negative electrode solution is 2.5-4.

0.

7. A method for recovering an acidic etching solution without generating chlorine according to claim 6, characterized in that: The Cu etching waste liquid 2+ The predetermined value of the ion concentration is 140 g / L; the Cu 2+ The predetermined value of the ion concentration is 30 g / L.

8. The method for recovering an acidic etching solution without generating chlorine according to claim 5, characterized in that: The trivalent iron salt is ferric chloride.

9. The method for recovering an acidic etching solution without generating chlorine according to claim 5, characterized in that: The current density of the electrolysis in the electrolytic cell is 100-400A / m 2 .

Images