A wastewater copper recovery treatment process for a PCB production line

Abstract

The application discloses a wastewater copper recovery treatment process of a PCB production line, and belongs to the field of PCB processing. 2+ The wastewater copper recovery treatment process comprises the following steps: determining the Fe 2+ content in wastewater, adding hydrogen peroxide into the wastewater with the molar ratio of hydrogen peroxide to Fe 2+ being 1:2-3, maintaining the pH at 2-2.5, reacting for 1-1.5 hours, removing the precipitate through filtration, and obtaining a first mixed solution; adding the first mixed solution into a three-stage reactor, adjusting the reaction pH of each stage of the three-stage reactor through a slow-release alkali agent, and obtaining a second mixed solution; mixing and reacting the ion imprinting polymer suspension and the second mixed solution through a microreactor; and desorption and electrolysis. The application excludes the influence of other substances on copper recovery.

Description

Technical Field

[0001] This invention belongs to the field of PCB board processing technology, and relates to a wastewater copper recovery treatment process for PCB board production lines. Background Technology

[0002] PCB manufacturing is a product used in electronics manufacturing to carry electronic components. It is mainly used in consumer electronics, communication equipment and industrial control. Its process types are divided into single-sided boards, double-sided boards and multilayer boards. The circuit interconnection structure is formed through core technologies such as drilling, etching and electroplating.

[0003] The etching solution contains a large amount of copper. Currently, in the process of recovering copper from etching waste liquid, it has been found that the copper recovery rate and purity are very low due to the complexity of the waste materials in the etching waste liquid. Summary of the Invention

[0004] The purpose of this invention is to provide a copper recovery process for wastewater from PCB production lines, which solves the problem that the copper recovery rate and purity are both very low in the current etching waste liquid copper recovery process.

[0005] The technical solution adopted in this invention is as follows:

[0006] A process for copper recovery from wastewater in a PCB production line, wherein the wastewater includes Cu 2+ Fe 2+ Fe 3+ EDTA-Fe 3+ Complex; the wastewater copper recovery treatment process includes the following steps:

[0007] S1. Determination of Fe in wastewater 2+ Content, in terms of Fe 2+ Based on the content, hydrogen peroxide was added to the wastewater. Hydrogen peroxide reacted with Fe... 2+ The molar ratio is 1:2-3, the pH is maintained at 2-2.5, the reaction is carried out for 1-1.5 hours, the precipitate is removed by filtration, and the first mixture is obtained.

[0008] S2. The first mixture is added to the three-stage reactor. The pH of the reaction is adjusted in each stage of the three-stage reactor by a slow-release alkali agent.

[0009] The reaction pH in the first stage reactor is 3-3.2, the reaction pH in the second stage reactor is 3.5-3.6, and the reaction pH in the third stage reactor is 4-4.2. The first mixture is filtered after passing through the three-stage reactor to obtain the second mixture.

[0010] S3. Prepare a copper ion-imprinted polymer suspension and adjust the pH to 5.2-5.3. Mix the ion-imprinted polymer suspension with the second mixture in a microreactor. After the reaction, filter to separate the liquid and solid phases, and collect the solid phase. Continue mixing the liquid phase with the copper ion-imprinted polymer suspension in a microreactor. After the reaction, filter to separate the liquid and solid phases, and collect the solid phase. Repeat this process until Cu is present in the liquid phase. 2+ The content tends to reach equilibrium, and all solid phases are collected;

[0011] S4. Desorption: All collected solid phases are eluted with acid to recover the copper ion-imprinted polymer, yielding Cu. 2+ Solution;

[0012] S5, Electrolysis: Cu 2+ Electrolytic copper is obtained by electrolysis of the solution, and the purity of the electrolytic copper is greater than 99.95%.

[0013] This application primarily addresses the etching waste liquid obtained during the developing and etching process in PCB manufacturing, as disclosed in patent number CN202410379230.7. To achieve a good etching effect, the etching components used are relatively complex, resulting in a complex composition of the generated etching waste liquid, primarily including a large amount of Cu. 2+ Fe 2+ Fe 3+ EDTA-Fe 3+ Complex; Fe 2+ Fe 3+ EDTA-Fe 3+ Complexes can affect copper recovery and purity; therefore, this application involves the development of a highly efficient copper extraction process that can match the aforementioned etching waste liquid; step S1 utilizes Fe in the waste liquid. 2+ Adding hydrogen peroxide achieved EDTA-Fe 3+ The complex is broken down; after breaking down the complex, iron ions can be fully and preferentially precipitated through a three-stage pH precipitation reaction, avoiding the co-precipitation of copper and iron; this is beneficial to improving the purity and extraction rate of copper; after removing the precipitate, the copper ion imprinted polymer is used to specifically adsorb copper ions, which can effectively enrich copper ions, and in the process of specific adsorption, the influence of other substances on copper extraction is further eliminated.

[0014] Furthermore, the optimal adsorption pH for ion-imprinted polymers is around 5. However, copper ions precipitate at around 5, and the precipitate hinders the adsorption of copper ions by the ion-imprinted polymer. Copper ion precipitation and adsorption compete for the same properties. To prioritize adsorption over precipitation, this application employs a microreactor. The microreactor allows for rapid and thorough contact between the second mixture and the copper ion-imprinted polymer suspension. During this contact, the collision frequency between copper ions and the ion-imprinted polymer is high. A higher collision frequency leads to higher adsorption efficiency. Increased adsorption efficiency means that adsorption takes precedence over precipitation during the reaction. Moreover, precipitation is a process, not an instantaneous reaction. Therefore, this application utilizes a fast-contact reaction process to simultaneously meet the optimal pH conditions for ion-imprinted polymer adsorption and prevent copper ion precipitation. In addition, the microreactor accelerates the adsorption efficiency of copper ions by the ion-imprinted polymer, significantly shortening the effective adsorption time.

[0015] Furthermore, the microreactor allows for the separate injection of the copper ion-imprinted polymer suspension and the second mixture through a Y-shaped tube. After being injected through the two ends of the Y-shaped tube, the copper ion-imprinted polymer suspension and the second mixture are mixed and reacted at the tee of the Y-shaped tube.

[0016] Furthermore, the slow-release alkali agent is poly(N-isopropylacrylamide-co-acrylic acid) modified shell powder.

[0017] Furthermore, the copper ion imprinted polymer is a Cu(II) ion imprinted polymer prepared in acetic acid solution using Cu(II) ions as templates, chitosan as a functional monomer, γ-(2,3-epoxypropoxy)propyltrimethoxysilane KH-560 as a coupling agent, and silica as a carrier, through surface molecular imprinting technology and sol-gel method.

[0018] Further, the poly(N-isopropylacrylamide-co-acrylic acid) modified shell powder is prepared by the following method: shell powder is dispersed in deionized water to obtain a suspension, N-isopropylacrylamide and acrylic acid are added to the suspension, and after stirring and heating to 60-65°C, N,N'-methylenebisacrylamide and potassium persulfate are added. After stirring evenly, the mixture is kept at a constant temperature for 6-8 hours. After the reaction is completed, the mixture is cooled, filtered, washed, and dried to obtain poly(N-isopropylacrylamide-co-acrylic acid) modified shell powder.

[0019] Furthermore, the mass ratio of the shell powder, N-isopropylacrylamide, and acrylic acid is 10:3:1, the amount of N,N'-methylenebisacrylamide added is 1.5% of the total mass of N-isopropylacrylamide and acrylic acid, and the amount of potassium persulfate added is 0.5% of the total mass of N-isopropylacrylamide and acrylic acid.

[0020] Furthermore, the volume ratio of the copper ion-imprinted polymer suspension to the second mixture injected through the same Y-tube is 1:8-12.

[0021] Furthermore, the volume ratio of the copper ion imprinted polymer suspension to the second mixture injected through the same Y-tube was 1:10, and the content of copper ion imprinted polymer in the copper ion imprinted polymer suspension was 45 g / L.

[0022] Furthermore, the three-stage reaction steps in the three-stage reactor in step S2 are as follows:

[0023] S2.1 First-stage reaction: The first mixture is added to the first-stage reactor at a reaction temperature of 25-30℃. Poly(N-isopropylacrylamide-co-acrylic acid) modified shell powder slow-release alkali agent is added. The pH of the system is adjusted to 3.0-3.2 under stirring, and then the temperature is raised to 35-40℃. The reaction is continued at 35-40℃ for 55-60 minutes. After the reaction is completed, the mixture is filtered to obtain the first filtrate.

[0024] S2.2 Second-stage reaction: The first filtrate enters the second-stage reactor. The reaction temperature is 25-30℃. Poly(N-isopropylacrylamide-co-acrylic acid) modified shell powder slow-release alkali agent is added. Under stirring, the pH of the system is adjusted to 3.5-3.6, and then the temperature is raised to 35-40℃. The reaction is continued at 35-40℃ for 30-40 minutes. After the reaction is completed, the mixture is filtered to obtain the second filtrate.

[0025] S2.3, Third-stage reaction: The second filtrate enters the third-stage reactor. The reaction temperature is 25-30℃. Poly(N-isopropylacrylamide-co-acrylic acid) modified shell powder slow-release alkali agent is added. Under stirring, the pH of the system is adjusted to 4-4.2, and then the temperature is raised to 35-40℃. The reaction is continued to stand at 35-40℃ for 15-20 minutes. After the reaction is completed, the mixture is filtered to obtain the second mixture.

[0026] Furthermore, in step S4, during desorption, all the collected solid phases are eluted with hydrochloric acid to recover the copper ion-imprinted polymer, yielding Cu. 2+ Solution.

[0027] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0028] 1. A copper recovery process for wastewater from a PCB production line combines the synergistic effects of complex breaking, precipitation, specific adsorption, elution, and electrolysis to efficiently extract copper from complex etching wastewater.

[0029] 2. This invention uses a three-stage gradient pH precipitation method combined with thermosensitive poly(N-isopropylacrylamide-co-acrylic acid) modified shell powder as a slow-release alkali agent, which avoids the co-precipitation of copper and iron while achieving sufficient precipitation of iron ions.

[0030] 3. This invention utilizes a fast-contact microreactor reaction process, which simultaneously satisfies the optimal pH conditions for ion-imprinted polymer adsorption and avoids copper ion precipitation; in addition, the microreactor also accelerates the adsorption efficiency of ion-imprinted polymer for copper ions, and significantly shortens the effective adsorption time. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort, wherein:

[0032] Figure 1 This is a flow chart of a PCB production line wastewater copper recovery process.

[0033] Figure 2 This is a physical image of the product of this invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, and not all embodiments. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0036] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0037] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0038] This invention provides a copper recovery process for wastewater from a PCB production line, wherein the wastewater includes Cu. 2+ Fe 2+ Fe 3+ EDTA-Fe 3+ Complexes; such as Figure 1 As shown, the wastewater copper recovery treatment process includes the following steps:

[0039] S1. Determination of Fe in wastewater 2+ Content, in terms of Fe 2+ Based on the content, hydrogen peroxide was added to the wastewater. Hydrogen peroxide reacted with Fe... 2+ The molar ratio is 1:2-3, the pH is maintained at 2-2.5, the reaction is carried out for 1-1.5 hours, the precipitate is removed by filtration, and the first mixture is obtained.

[0040] S2. The first mixture is added to the three-stage reactor. The pH of the reaction is adjusted in each stage of the three-stage reactor by a slow-release alkali agent.

[0041] The reaction pH in the first stage reactor is 3-3.2, the reaction pH in the second stage reactor is 3.5-3.6, and the reaction pH in the third stage reactor is 4-4.2. The first mixture is filtered after passing through the three-stage reactor to obtain the second mixture.

[0042] S3. Prepare a copper ion-imprinted polymer suspension and adjust the pH to 5.2-5.3. Mix the ion-imprinted polymer suspension with the second mixture in a microreactor. After the reaction, filter to separate the liquid and solid phases, and collect the solid phase. Continue mixing the liquid phase with the copper ion-imprinted polymer suspension in a microreactor. After the reaction, filter to separate the liquid and solid phases, and collect the solid phase. Repeat this process until Cu is present in the liquid phase. 2+The content tends to reach equilibrium, and all solid phases are collected;

[0043] S4. Desorption: All collected solid phases are eluted with acid to recover the copper ion-imprinted polymer, yielding Cu. 2+ Solution;

[0044] S5, Electrolysis: Cu 2+ Electrolytic copper is obtained by electrolysis of the solution, and the purity of the electrolytic copper is greater than 99.95%.

[0045] The microreactor uses a Y-shaped tube to separately inject the copper ion-imprinted polymer suspension and the second mixture. After being injected through the two ends of the Y-shaped tube, the copper ion-imprinted polymer suspension and the second mixture are mixed and reacted at the tee of the Y-shaped tube.

[0046] The slow-release alkali agent is poly(N-isopropylacrylamide-co-acrylic acid) modified shell powder.

[0047] The copper ion-imprinted polymer is prepared in acetic acid solution using Cu(II) ions as a template, chitosan as a functional monomer, γ-(2,3-epoxypropoxy)propyltrimethoxysilane KH-560 as a coupling agent, and silica as a carrier, employing surface molecular imprinting technology and a sol-gel method. This technology is existing technology.

[0048] The poly(N-isopropylacrylamide-co-acrylic acid) modified shell powder was prepared by the following method: shell powder was dispersed in deionized water to obtain a suspension. N-isopropylacrylamide and acrylic acid were added to the suspension. After stirring and heating to 60-65℃, N,N'-methylenebisacrylamide and potassium persulfate were added. After stirring evenly, the mixture was kept at a constant temperature for 6-8 hours. After the reaction was completed, the mixture was cooled, filtered, washed, and dried to obtain poly(N-isopropylacrylamide-co-acrylic acid) modified shell powder.

[0049] The mass ratio of shell powder, N-isopropylacrylamide, and acrylic acid is 10:3:1. The amount of N,N'-methylenebisacrylamide added is 1.5% of the total mass of N-isopropylacrylamide and acrylic acid, and the amount of potassium persulfate added is 0.5% of the total mass of N-isopropylacrylamide and acrylic acid.

[0050] The volume ratio of the copper ion-imprinted polymer suspension to the second mixture injected through the same Y-tube was 1:8-12.

[0051] The volume ratio of the copper ion imprinted polymer suspension to the second mixture injected through the same Y-tube was 1:10, and the copper ion imprinted polymer content in the suspension was 45 g / L.

[0052] The three-stage reaction steps in the three-stage reactor in step S2 are as follows:

[0053] S2.1 First-stage reaction: The first mixture is added to the first-stage reactor at a reaction temperature of 25-30℃. Poly(N-isopropylacrylamide-co-acrylic acid) modified shell powder slow-release alkali agent is added. The pH of the system is adjusted to 3.0-3.2 under stirring, and then the temperature is raised to 35-40℃. The reaction is continued at 35-40℃ for 55-60 minutes. After the reaction is completed, the mixture is filtered to obtain the first filtrate.

[0054] S2.2 Second-stage reaction: The first filtrate enters the second-stage reactor. The reaction temperature is 25-30℃. Poly(N-isopropylacrylamide-co-acrylic acid) modified shell powder slow-release alkali agent is added. Under stirring, the pH of the system is adjusted to 3.5-3.6, and then the temperature is raised to 35-40℃. The reaction is continued at 35-40℃ for 30-40 minutes. After the reaction is completed, the mixture is filtered to obtain the second filtrate.

[0055] S2.3, Third-stage reaction: The second filtrate enters the third-stage reactor. The reaction temperature is 25-30℃. Poly(N-isopropylacrylamide-co-acrylic acid) modified shell powder slow-release alkali agent is added. Under stirring, the pH of the system is adjusted to 4-4.2, and then the temperature is raised to 35-40℃. The reaction is continued to stand at 35-40℃ for 15-20 minutes. After the reaction is completed, the mixture is filtered to obtain the second mixture.

[0056] In step S4, during desorption, all the collected solid phases are eluted with hydrochloric acid to recover the copper ion-imprinted polymer, yielding Cu. 2+ Solution.

[0057] Based on the above, the specific implementation method is as follows:

[0058] Example 1

[0059] A preferred embodiment of the present invention provides a copper recovery process for wastewater from a PCB production line, wherein the wastewater includes Cu. 2+ Fe 2+ Fe 3+ EDTA-Fe 3+ Complex; Cu 2+ Fe 2+ Fe 3+ EDTA-Fe 3+ The concentrations of the complexes were 120 g / L, 14 g / L, 5 g / L, and 10 g / L (rounded to the nearest integer).

[0060] The wastewater copper recovery treatment process includes the following steps:

[0061] S1. Determination of Fe in wastewater 2+Content, in terms of Fe 2+ Based on the content, hydrogen peroxide was added to the wastewater. Hydrogen peroxide reacted with Fe... 2+ The molar ratio was 1:2, the pH was maintained at 2-2.5, the reaction was carried out for 1 hour, the precipitate was removed by filtration, and the first mixture was obtained.

[0062] S2. Add the first mixture to the three-stage reactor. The pH of each stage of the three-stage reactor is adjusted by a slow-release alkali agent, which is poly(N-isopropylacrylamide-co-acrylic acid) modified seashell powder. The specific steps are as follows:

[0063] S2.1 First-stage reaction: The first mixture is added to the first-stage reactor at a reaction temperature of 30°C. Poly(N-isopropylacrylamide-co-acrylic acid) modified shell powder slow-release alkali agent is added. The pH of the system is adjusted to 3.0-3.2 under stirring, and then the temperature is raised to 40°C. The reaction is allowed to continue at 40°C for 60 minutes. After the reaction is completed, the mixture is filtered to obtain the first filtrate.

[0064] S2.2 Second-stage reaction: The first filtrate enters the second-stage reactor at a reaction temperature of 25°C. Poly(N-isopropylacrylamide-co-acrylic acid) modified shell powder slow-release alkali agent is added. The pH of the system is adjusted to 3.5-3.6 under stirring, and then the temperature is raised to 40°C. The reaction is allowed to continue at 40°C for 40 minutes. After the reaction is completed, the mixture is filtered to obtain the second filtrate.

[0065] S2.3, Third-stage reaction: The second filtrate enters the third-stage reactor. The reaction temperature is 25℃. Poly(N-isopropylacrylamide-co-acrylic acid) modified shell powder slow-release alkali agent is added. The pH of the system is adjusted to 4-4.2 under stirring, and then the temperature is raised to 40℃. The reaction is allowed to continue to stand at 40℃ for 15 minutes. After the reaction is completed, the mixture is filtered to obtain the second mixture.

[0066] S3. Prepare a copper ion-imprinted polymer suspension with a concentration of 45 g / L, adjust the pH to 5.2-5.3, and mix the ion-imprinted polymer suspension with the second mixture in a microreactor. The volume ratio of the copper ion-imprinted polymer suspension to the second mixture injected through the same Y-tube in the microreactor is 1:10. After the reaction, filter to separate the liquid and solid phases, and collect the solid phase. Continue to mix the liquid phase with the copper ion-imprinted polymer suspension in the microreactor, filter after the reaction, separate the liquid and solid phases, and collect the solid phase. Repeat the operation until Cu in the liquid phase is removed. 2+ The content tends to reach equilibrium, and all solid phases and all liquid phases are collected separately;

[0067] S4. Desorption: All collected solid phases are eluted with hydrochloric acid to recover the copper ion-imprinted polymer, yielding Cu. 2+ Solution;

[0068] S5, Electrolysis: Cu 2+ Electrolytic copper is obtained by electrolysis of the solution, and the purity of the electrolytic copper is greater than 99.95%.

[0069] Example 2

[0070] Based on Example 1, this preferred embodiment of the present invention provides a copper recovery process for wastewater from a PCB production line, wherein the wastewater includes Cu. 2+ Fe 2+ Fe 3+ EDTA-Fe 3+ Complex; Cu 2+ Fe 2+ Fe 3+ EDTA-Fe 3+ The concentrations of the complexes were 120 g / L, 14 g / L, 5 g / L, and 10 g / L, respectively.

[0071] The wastewater copper recovery treatment process includes the following steps:

[0072] S1. Determination of Fe in wastewater 2+ Content, in terms of Fe 2+ Based on the content, hydrogen peroxide was added to the wastewater. Hydrogen peroxide reacted with Fe... 2+ The molar ratio was 1:2.5, the pH was maintained at 2-2.5, the reaction was carried out for 1.5 hours, the precipitate was removed by filtration, and the first mixture was obtained.

[0073] S2. Add the first mixture to the three-stage reactor. The pH of each stage of the three-stage reactor is adjusted by a slow-release alkali agent, which is poly(N-isopropylacrylamide-co-acrylic acid) modified seashell powder. The specific steps are as follows:

[0074] S2.1 First-stage reaction: The first mixture is added to the first-stage reactor at a reaction temperature of 30°C. Poly(N-isopropylacrylamide-co-acrylic acid) modified shell powder slow-release alkali agent is added. The pH of the system is adjusted to 3.0-3.2 under stirring, and then the temperature is raised to 40°C. The reaction is allowed to continue at 40°C for 60 minutes. After the reaction is completed, the mixture is filtered to obtain the first filtrate.

[0075] S2.2 Second-stage reaction: The first filtrate enters the second-stage reactor at a reaction temperature of 25°C. Poly(N-isopropylacrylamide-co-acrylic acid) modified shell powder slow-release alkali agent is added. The pH of the system is adjusted to 3.5-3.6 under stirring, and then the temperature is raised to 40°C. The reaction is allowed to continue at 40°C for 40 minutes. After the reaction is completed, the mixture is filtered to obtain the second filtrate.

[0076] S2.3, Third-stage reaction: The second filtrate enters the third-stage reactor. The reaction temperature is 25℃. Poly(N-isopropylacrylamide-co-acrylic acid) modified shell powder slow-release alkali agent is added. Under stirring, the pH of the system is adjusted to 4-4.2 and then the temperature is raised to 40℃. The reaction is allowed to continue at 40℃ for 20 minutes. After the reaction is completed, the mixture is filtered to obtain the second mixture.

[0077] S3. Prepare a copper ion-imprinted polymer suspension with a concentration of 45 g / L, adjust the pH to 5.2-5.3, and react the ion-imprinted polymer suspension with the second mixture in a microreactor. The volume ratio of the copper ion-imprinted polymer suspension to the second mixture injected through the same Y-tube in the microreactor is 1:10. After the reaction, filter to separate the liquid and solid phases, and collect the solid phase. The liquid phase is then reacted with the copper ion-imprinted polymer suspension again in the microreactor. After the reaction, filter to separate the liquid and solid phases, and collect the solid phase. Repeat the operation until the Cu in the liquid phase is reduced. 2+ The content tends to reach equilibrium, and all solid phases and all liquid phases are collected separately;

[0078] S4. Desorption: All collected solid phases are eluted with hydrochloric acid to recover the copper ion-imprinted polymer, yielding Cu. 2+ Solution;

[0079] S5, Electrolysis: Cu 2+ Electrolytic copper is obtained by electrolysis of the solution, and the purity of the electrolytic copper is greater than 99.95%.

[0080] Example 3

[0081] Based on Example 1, this preferred embodiment of the present invention provides a copper recovery process for wastewater from a PCB production line, wherein the wastewater includes Cu. 2+ Fe 2+ Fe 3+ EDTA-Fe 3+ Complex; Cu 2+ Fe 2+ Fe 3+ EDTA-Fe 3+ The concentrations of the complexes were 120 g / L, 14 g / L, 5 g / L, and 10 g / L, respectively.

[0082] The wastewater copper recovery treatment process includes the following steps:

[0083] S1. Determination of Fe in wastewater 2+ Content, in terms of Fe 2+ Based on the content, hydrogen peroxide was added to the wastewater. Hydrogen peroxide reacted with Fe... 2+ The molar ratio was 1:3, the pH was maintained at 2-2.5, the reaction was carried out for 1.5 hours, the precipitate was removed by filtration, and the first mixture was obtained.

[0084] S2. Add the first mixture to the three-stage reactor. The pH of each stage of the three-stage reactor is adjusted by a slow-release alkali agent, which is poly(N-isopropylacrylamide-co-acrylic acid) modified seashell powder. The specific steps are as follows:

[0085] S2.1 First-stage reaction: The first mixture is added to the first-stage reactor at a reaction temperature of 30°C. Poly(N-isopropylacrylamide-co-acrylic acid) modified shell powder slow-release alkali agent is added. The pH of the system is adjusted to 3.0-3.2 under stirring, and then the temperature is raised to 40°C. The reaction is allowed to continue at 40°C for 60 minutes. After the reaction is completed, the mixture is filtered to obtain the first filtrate.

[0086] S2.2 Second-stage reaction: The first filtrate enters the second-stage reactor at a reaction temperature of 25°C. Poly(N-isopropylacrylamide-co-acrylic acid) modified shell powder slow-release alkali agent is added. The pH of the system is adjusted to 3.5-3.6 under stirring, and then the temperature is raised to 40°C. The reaction is allowed to continue at 40°C for 40 minutes. After the reaction is completed, the mixture is filtered to obtain the second filtrate.

[0087] S2.3, Third-stage reaction: The second filtrate enters the third-stage reactor. The reaction temperature is 25℃. Poly(N-isopropylacrylamide-co-acrylic acid) modified shell powder slow-release alkali agent is added. Under stirring, the pH of the system is adjusted to 4-4.2 and then the temperature is raised to 40℃. The reaction is allowed to continue at 40℃ for 20 minutes. After the reaction is completed, the mixture is filtered to obtain the second mixture.

[0088] S3. Prepare a copper ion-imprinted polymer suspension with a concentration of 45 g / L, adjust the pH to 5.2-5.3, and react the ion-imprinted polymer suspension with the second mixture in a microreactor. The volume ratio of the copper ion-imprinted polymer suspension to the second mixture injected through the same Y-tube in the microreactor is 1:10. After the reaction, filter to separate the liquid and solid phases, and collect the solid phase. The liquid phase is then reacted with the copper ion-imprinted polymer suspension again in the microreactor. After the reaction, filter to separate the liquid and solid phases, and collect the solid phase. Repeat the operation until the Cu in the liquid phase is reduced. 2+ The content tends to reach equilibrium, and all solid phases and all liquid phases are collected separately;

[0089] S4. Desorption: All collected solid phases are eluted with hydrochloric acid to recover the copper ion-imprinted polymer, yielding Cu. 2+ Solution;

[0090] S5, Electrolysis: Cu 2+ Electrolytic copper is obtained by electrolysis of the solution, and the purity of the electrolytic copper is greater than 99.95%.

[0091] Example 4

[0092] Based on Example 2, the difference from Example 2 is that the volume ratio of the copper ion-imprinted polymer suspension to the second mixture introduced into the same Y-tube in the microreactor in this example is 1:8; all other aspects are the same.

[0093] Example 5

[0094] Based on Example 2, the difference from Example 2 is that the volume ratio of the copper ion-imprinted polymer suspension to the second mixture in the same Y-tube of the microreactor in this example is 1:12; all other aspects are the same.

[0095] Comparative Example 1

[0096] Based on Example 1, the difference from Example 1 is that hydrogen peroxide and Fe in this comparative example... 2+ The molar ratio is 1:1, and all other parameters are the same.

[0097] Comparative Example 2

[0098] Based on Example 1, the difference from Example 1 is that hydrogen peroxide and Fe in this comparative example... 2+ The molar ratio is 1:4.

[0099] Comparative Example 3

[0100] Based on Example 2, the difference from Example 2 is that this comparative example does not perform step S1, and the wastewater treatment starts directly from step S2, while the rest is the same.

[0101] Comparative Example 4

[0102] Based on Example 2, the difference from Example 2 is that step S2 is not performed in this comparative example. The mixture obtained after step S1 directly enters step S3 to be mixed and reacted with the copper ion imprinted polymer suspension. The rest is the same.

[0103] Comparative Example 5

[0104] Based on Example 2, unlike Example 2, this comparative example does not perform steps S3 and S4, and the mixture after steps S1 and S2 is directly electrolyzed.

[0105] Comparative Example 6

[0106] Based on Example 2, the difference from Example 2 is that the first-stage reaction is not carried out in step S2 of this comparative example, and the second-stage reaction is directly entered. The rest are the same.

[0107] Comparative Example 7

[0108] Based on Example 2, the difference from Example 2 is that the second-stage reaction is not carried out in step S2 of this comparative example. After the first-stage reaction is completed, the third-stage reaction is directly entered. The rest are the same.

[0109] Comparative Example 8

[0110] Based on Example 2, the difference from Example 2 is that the third-stage reaction is not carried out in step S2 of this comparative example. After the first-stage reaction and the second-stage reaction are completed, the process directly proceeds to S3. The rest is the same.

[0111] Comparative Example 9

[0112] Based on Example 2, the difference from Example 2 is that a microreactor is not used in step S3 of this comparative example; instead, a conventional reaction vessel is used directly. All other aspects are the same.

[0113] Comparative Example 10

[0114] Based on Example 2, the difference from Example 2 is that the slow-release alkali agent in step S2 of this comparative example is unmodified shell powder.

[0115] Comparative Example 11

[0116] Based on Example 2, the difference from Example 2 is that in this comparative example, step S2 only involves the third-order reaction, with a reaction time of 1.5 hours, and the first and second-order reactions are not performed, while the rest are the same.

[0117] Blank group

[0118] Based on Example 1, the wastewater includes Cu 2+ Fe 2+ Fe 3+ EDTA-Fe 3+ Complex; Cu 2+ Fe 2+ Fe 3+ EDTA-Fe 3+ The concentrations of the complexes were 120 g / L, 14 g / L, 5 g / L, and 10 g / L, respectively, and the wastewater was directly electrolyzed.

[0119] Experimental Example 1

[0120] Take 1L of wastewater, the Cu in 1L of wastewater 2+ Fe 2+ Fe 3+ EDTA-Fe 3+ The concentrations of the complexes were 120 g / L, 14 g / L, 5 g / L, and 10 g / L, respectively.

[0121] The copper recovery rate and purity of electrolytic copper were tested after treatment using Examples 1-5, Comparative Examples 1-11, and the blank group; the results are shown in Table 1.

[0122] The method for detecting copper recovery rate is as follows: Actual recovery rate (%) = (Actual recovery amount / Theoretical recovery amount) × 100%.

[0123] The purity test method for electrolytic copper refers to the national standard GB / T 5246-2007-"GB / T 5121.1, Chemical Analysis Methods for Copper and Copper Alloys: Determination of Copper Content".

[0124] Table 1. Copper recovery rate and purity of electrolytic copper

[0125] Actual recovery rate Electrolytic copper purity Example 1 98.8-99.1% ≥99.95% Example 2 99.4-99.5% ＞99.95% Example 3 99.1-99.3% ＞99.95% Example 4 98.5-98.7% ≥99.95% Example 5 98.2-98.3% ≥99.95% Comparative Example 1 97.1-97.3% ≤99.91% Comparative Example 2 97.4-97.5% ≤99.92% Comparative Example 3 91.5-91.8% ≤99.88% Comparative Example 4 88.4-88.6% ＜99% Comparative Example 5 90-90.2% ＜99.95% Comparative Example 6 ＜98% ＜99.95% Comparative Example 7 ＜98% ＜99.95% Comparative Example 8 ＜98% ＜99.95% Comparative Example 9 ＜95% ≤99.91% Comparative Example 10 ＜95% ＜99.95% Comparative Example 11 ＜95% ＜99.95% Blank group 80-80.5% ＜98.8%

[0126] The actual copper recovery rate of this invention is over 98%, even reaching 99.5%, and the purity of the electrolytic copper of this invention is ≥99.95%.

[0127] Experimental Example 2

[0128] The copper ion concentrations in the first mixture in step S1, the second mixture, the liquid phase in step S3, and the copper ion concentration after desorption in step S4 of Examples 1-5 were measured, and the results are shown in Table 2.

[0129] Table 2. Copper ion concentration (g / L) at each stage

[0130] Step S1: Copper ion concentration in the first mixture Step S2: Copper ion concentration in the second mixture The concentration of copper ions in the total liquid phase of S3 The concentration of copper ions after desorption in step S4 Example 1 119.2±0.1 118.9±0.1 ＜0.5 118.8±0.05 Example 2 119.7±0.1 119.6±0.1 ＜0.5 119.6±0.05 Example 3 119.3±0.1 119.1±0.1 ＜0.5 119.1±0.05 Example 4 119.6±0.1 119.6±0.1 ＜1 118.5±0.05 Example 5 119.7±0.1 119.7±0.1 ＜1 118.2±0.05

[0131] Experimental Example 3

[0132] The total adsorption time of copper ions in step S3 of Example 2 and the adsorption time of Comparative Example 9 were measured, and the results are shown in Table 3.

[0133] Table 3 Copper ion adsorption time

[0134] The total adsorption time of copper ions in step S3 of Example 2 Adsorption time of Comparative Example 9 Copper ion adsorption time ＜1h ＞2h

[0135] The adsorption efficiency of step S3 using a microreactor is significantly better than that without a microreactor. Combined with the data in Tables 1-3, it can be seen that this application solves the problem of very low copper recovery rate and purity in current etching wastewater copper recovery processes; the copper powder obtained from electrolytic copper processing within the scope of Example 2 of this application is as follows... Figure 2 As shown.

[0136] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A wastewater copper recovery treatment process for a PCB production line, characterized in that: The wastewater includes Cu 2+ Fe 2+ Fe 3+ EDTA-Fe 3+ Complex; the wastewater copper recovery treatment process includes the following steps: S1. Determination of Fe in wastewater 2+ Content, in terms of Fe 2+ Based on the content, hydrogen peroxide was added to the wastewater. Hydrogen peroxide reacted with Fe... 2 + The molar ratio is 1:2-3, the pH is maintained at 2-2.5, the reaction is carried out for 1-1.5 hours, the precipitate is removed by filtration, and the first mixture is obtained. S2. The first mixture is added to the three-stage reactor. The pH of the reaction is adjusted in each stage of the three-stage reactor by a slow-release alkali agent. The reaction pH in the first stage reactor is 3-3.2, the reaction pH in the second stage reactor is 3.5-3.6, and the reaction pH in the third stage reactor is 4-4.

2. The first mixture is filtered after passing through the three-stage reactor to obtain the second mixture. S3. Prepare a copper ion-imprinted polymer suspension and adjust the pH to 5.2-5.

3. Mix the ion-imprinted polymer suspension with the second mixture in a microreactor. After the reaction, filter to separate the liquid and solid phases, and collect the solid phase. Continue mixing the liquid phase with the copper ion-imprinted polymer suspension in a microreactor. After the reaction, filter to separate the liquid and solid phases, and collect the solid phase. Repeat this process until Cu is present in the liquid phase. 2+ The content tends to reach equilibrium, and all solid phases are collected; S4. Desorption: All collected solid phases are eluted with acid to recover the copper ion-imprinted polymer, yielding Cu. 2+ Solution; S5, Electrolysis: Cu 2+ Electrolytic copper is obtained by electrolysis of the solution, and the purity of the electrolytic copper is greater than 99.95%. The slow-release alkali agent is poly(N-isopropylacrylamide-co-acrylic acid) modified shell powder; The copper ion imprinted polymer is a Cu(II) ion imprinted polymer prepared in acetic acid solution using Cu(II) ions as templates, chitosan as a functional monomer, γ-(2,3-epoxypropoxy)propyltrimethoxysilane KH-560 as a coupling agent, and silica as a carrier, through surface molecular imprinting technology and sol-gel method.

2. The wastewater copper recovery treatment process for a PCB production line according to claim 1, characterized in that: The microreactor uses a Y-shaped tube to separately inject the copper ion-imprinted polymer suspension and the second mixture. After being injected through the two ends of the Y-shaped tube, the copper ion-imprinted polymer suspension and the second mixture are mixed and reacted at the tee of the Y-shaped tube.

3. The wastewater copper recovery treatment process for a PCB production line according to claim 1, characterized in that: The poly(N-isopropylacrylamide-co-acrylic acid) modified shell powder was prepared by the following method: shell powder was dispersed in deionized water to obtain a suspension. N-isopropylacrylamide and acrylic acid were added to the suspension. After stirring and heating to 60-65℃, N,N'-methylenebisacrylamide and potassium persulfate were added. After stirring evenly, the mixture was kept at a constant temperature for 6-8 hours. After the reaction was completed, the mixture was cooled, filtered, washed, and dried to obtain poly(N-isopropylacrylamide-co-acrylic acid) modified shell powder.

4. The wastewater copper recovery treatment process for a PCB production line according to claim 3, characterized in that: The mass ratio of shell powder, N-isopropylacrylamide, and acrylic acid is 10:3:

1. The amount of N,N'-methylenebisacrylamide added is 1.5% of the total mass of N-isopropylacrylamide and acrylic acid, and the amount of potassium persulfate added is 0.5% of the total mass of N-isopropylacrylamide and acrylic acid.

5. The wastewater copper recovery treatment process for a PCB production line according to claim 2, characterized in that: The volume ratio of the copper ion-imprinted polymer suspension to the second mixture injected through the same Y-tube was 1:8-12.

6. The wastewater copper recovery treatment process for a PCB production line according to claim 5, characterized in that: The volume ratio of the copper ion imprinted polymer suspension to the second mixture injected through the same Y-tube was 1:10, and the copper ion imprinted polymer content in the suspension was 45 g / L.

7. The wastewater copper recovery treatment process for a PCB production line according to claim 1, characterized in that: The three-stage reaction steps in the three-stage reactor in step S2 are as follows: S2.1 First-stage reaction: The first mixture is added to the first-stage reactor at a reaction temperature of 25-30℃. Poly(N-isopropylacrylamide-co-acrylic acid) modified shell powder slow-release alkali agent is added. The pH of the system is adjusted to 3.0-3.2 under stirring, and then the temperature is raised to 35-40℃. The reaction is allowed to continue at 35-40℃ for 55-60 minutes. After the reaction is completed, the mixture is filtered to obtain the first filtrate. S2.2 Second-stage reaction: The first filtrate enters the second-stage reactor. The reaction temperature is 25-30℃. Poly(N-isopropylacrylamide-co-acrylic acid) modified shell powder slow-release alkali agent is added. Under stirring, the pH of the system is adjusted to 3.5-3.6, and then the temperature is raised to 35-40℃. The reaction is continued to stand at 35-40℃ for 30-40 minutes. After the reaction is completed, the mixture is filtered to obtain the second filtrate. S2.3, Third-stage reaction: The second filtrate enters the third-stage reactor. The reaction temperature is 25-30℃. Poly(N-isopropylacrylamide-co-acrylic acid) modified shell powder slow-release alkali agent is added. Under stirring, the pH of the system is adjusted to 4-4.2, and then the temperature is raised to 35-40℃. The reaction is continued to stand at 35-40℃ for 15-20 minutes. After the reaction is completed, the mixture is filtered to obtain the second mixture.

8. The wastewater copper recovery treatment process for a PCB production line according to claim 1, characterized in that: In step S4, during desorption, all the collected solid phases are eluted with hydrochloric acid to recover the copper ion-imprinted polymer, yielding Cu. 2+ Solution.

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