Electrochemical copper plating waste liquid electrochemical oxidation and high-value copper recovery method

Abstract

The invention belongs to the technical field of electronic circuit manufacturing waste liquid treatment and resource recovery, and particularly relates to a chemical copper plating waste liquid electrochemical oxidation and copper high-value recovery method. The chemical copper plating waste liquid is sequentially subjected to pretreatment, electrochemical oxidation through a ruthenium-iridium-titanium electrode, precipitation reaction, solid-liquid separation, acid dissolution, solvent extraction and refining, back extraction and electrodeposition recovery, and a metal copper product is obtained. The method provided by the invention is an integrated method based on ruthenium iridium titanium electrode electrochemical oxidation-alkali precipitation-extraction refining, realizes efficient decomposition of organic complexes and high-valued recovery of copper resources, and can be widely applied to harmless treatment and resource utilization of the chemical copper plating waste liquid in the industries of printed circuit boards, integrated circuit packaging and the like.

Description

Technical Field

[0001] This invention belongs to the field of waste liquid treatment and resource recycling technology in electronic circuit manufacturing, specifically relating to a method for electrochemical oxidation and high-value copper recovery of chemical copper plating waste liquid. Background Technology

[0002] Chemical copper plating technology is widely used in processes such as through-hole metallization and micro-circuit fabrication in electronic circuit manufacturing. The main components of the chemical copper plating solution are copper sulfate (8~15g / L), formaldehyde reducing agent (2~5g / L), EDTA or potassium sodium tartrate complexing agent (10~20g / L), 2,2'-bipyridine stabilizer, etc. The copper ion concentration in the waste liquid is usually 5000~15000mg / L.

[0003] The chemical copper plating waste liquid has the following characteristics: (1) high copper ion concentration, which forms a stable complex with organic complexing agent; (2) high organic matter concentration (COD is usually 15000~45000mg / L), which has strong biological toxicity; (3) high pH value (9~13), which has strong corrosiveness; (4) large stability constant of complex, which is difficult to crack by conventional methods.

[0004] Existing technologies for treating waste liquid from electroless copper plating include chemical precipitation, but the removal rate is only 60-80% because the complexed copper is difficult to completely precipitate. Summary of the Invention

[0005] The purpose of this invention is to provide a method for electrochemical oxidation and high-value recovery of copper from chemical copper plating wastewater. The method provided by this invention effectively solves the technical problem of strong stability of organic complexes and difficulty in effectively separating and recovering copper ions in chemical copper plating wastewater. It realizes the efficient decomposition of organic complexes and the high-value recovery of copper resources, and can be widely used in the harmless treatment and resource utilization of chemical copper plating wastewater in industries such as printed circuit boards (PCBs) and integrated circuit packaging.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for electrochemical oxidation and high-value copper recovery of chemical copper plating wastewater, comprising the following steps: The chemical copper plating waste liquid is pretreated to obtain pretreated waste liquid. The pretreatment reagents include acid reagents and redox substances. The pretreated waste liquid was electrochemically oxidized using a ruthenium-iridium-titanium electrode to obtain the electrolyzed waste liquid; The waste liquid after electrolysis was mixed with an alkaline reagent to carry out a precipitation reaction, and then solid-liquid separation was performed to obtain Cu(OH)2 precipitate; The Cu(OH)2 precipitate was dissolved in acid to obtain a copper ion solution; The copper ion solution was purified by solvent extraction using LIX984N extractant to obtain a copper-loaded organic phase. The copper-loaded organic phase was back-extracted with an acid solution to obtain a pure copper ion solution. The pure copper ion solution is used as an electrolyte for electrodeposition to recover metallic copper products.

[0007] Preferably, the pretreatment includes the following steps: filtering the chemical copper plating waste liquid to obtain a filtrate; adjusting the pH of the filtrate to 2-3 using an acid reagent, wherein the acid reagent is a sulfuric acid solution, to obtain an acidic waste liquid; mixing the acidic waste liquid with a redox substance, wherein the redox substance is an H2O2 solution, the H2O2 content in the H2O2 solution is 20-35 wt%, and the amount of the redox substance is 0.3-0.8% of the volume of the chemical copper plating waste liquid, to obtain a pretreated waste liquid.

[0008] Preferably, the ruthenium-iridium-titanium electrode comprises RuO2 and IrO2, wherein the molar ratio of RuO2 to IrO2 is 30~70:70~30; the electrochemical oxidation uses the ruthenium-iridium-titanium electrode as the anode and a titanium plate as the cathode; the conditions for the electrochemical oxidation include a current density of 80~150 mA / cm². 2 The cell voltage is 2.0~3.5V, the electrolysis time is 2~4h, and the electrolysis temperature is 30~50℃.

[0009] Preferably, the alkaline reagent is an alkali metal hydroxide; the conditions for the precipitation reaction include: pH value of 9~10.5; pH value accuracy of ±0.2; reaction temperature of 25~40℃; time of 30~60min; and the precipitation reaction is carried out under stirring conditions.

[0010] Preferably, the precipitation reaction further includes a flocculant, wherein the mass of the flocculant accounts for 0.5~2 mg / L of the volume of the chemical copper plating waste liquid.

[0011] Preferably, the Cu(OH)2 precipitate has a water content of 50-70%; the acid dissolution uses a sulfuric acid solution, and the mass content of H2SO4 in the sulfuric acid solution is 10-15%; the pH value of the copper ion solution is 1.5-2.5; and the concentration of copper ions in the copper ion solution is 40-60 g / L.

[0012] Preferably, the LIX984N extractant is a LIX984N-kerosene system; the solvent extraction and purification conditions include: an O / A ratio of 1.5 to 2.5:1, 3 to 4 extraction stages, a contact time of 5 to 10 minutes per stage, and a phase separation time of 3 to 5 minutes.

[0013] Preferably, the acid solution used for back-extraction is a sulfuric acid solution, and the mass content of H2SO4 in the sulfuric acid solution is 2~3 mol / L; the number of back-extraction stages is 2~3 stages; and the concentration of copper ions in the pure copper ion solution is 45~55 g / L.

[0014] Preferably, the electrodeposition recovery uses 316L stainless steel as the cathode and lead-tin alloy as the anode. The conditions for electrodeposition recovery include: the electrodeposition solution composition includes CuSO4 and H2SO4, and the current density is 250~350 mA / cm². 2 The cell voltage is 2~2.5V, the electrowinning temperature is 40~60℃, and the electrowinning time is 3~12h; the copper product is a high-purity copper plate with a purity ≥99.8%.

[0015] Preferably, the solid-liquid separation further yields a supernatant, and the solvent extraction purification further yields an aqueous phase after extraction; the process further includes: combining the supernatant and the aqueous phase after extraction and then performing physical adsorption, wherein the physical adsorption is performed using activated carbon, and the effluent after physical adsorption has the following parameters: COD < 50 mg / L, Cu 2+ <0.5mg / L.

[0016] This invention provides a method for electrochemical oxidation and high-value copper recovery from chemical copper plating wastewater, comprising the following steps: pretreating the chemical copper plating wastewater to obtain pretreated wastewater, wherein the pretreatment reagents include acid reagents and redox substances; electrochemically oxidizing the pretreated wastewater using a ruthenium-iridium-titanium electrode to obtain electrolyzed wastewater; mixing the electrolyzed wastewater with an alkaline reagent for a precipitation reaction, followed by solid-liquid separation to obtain Cu(OH)2 precipitate; dissolving the Cu(OH)2 precipitate in acid to obtain a copper ion solution; solvent extraction and purification of the copper ion solution using LIX984N extractant to obtain a copper-loaded organic phase; back-extracting the copper-loaded organic phase with an acid solution to obtain a pure copper ion solution; and using the pure copper ion solution as an electrolyte for electrowinning to obtain metallic copper product. This invention aims to solve the technical challenge of the high stability of organic complexes in chemical copper plating wastewater and the difficulty in effectively separating and recovering copper ions. The method provided by this invention is an integrated approach based on ruthenium-iridium-titanium electrodes for electrochemical oxidation, alkaline precipitation, and extraction purification, achieving efficient decomposition of organic complexes and high-value recovery of copper resources. This method enables the decomposition of organic complexes and high-value recovery of copper ions from chemical copper plating wastewater, and can be used for the harmless treatment and resource utilization of chemical copper plating wastewater in industries such as printed circuit board (PCB) and integrated circuit packaging. Compared with existing technologies, this invention has the following beneficial effects: This invention uses a ruthenium-iridium-titanium electrode for electrochemical oxidation of pretreated wastewater. The ruthenium-iridium-titanium electrode has a high oxygen evolution potential and can generate strong oxidizing ·OH free radicals, thereby achieving an organic complex mineralization rate of ≥95% and a COD removal rate of ≥90%. At the same time, the electrochemical oxidation using the ruthenium-iridium-titanium electrode has high current efficiency and energy consumption that is 20-30% lower than that of the traditional Ti / PbO2 electrode.

[0017] The method provided by this invention eliminates the need for Fenton's reagent, thus avoiding the generation of large amounts of iron sludge; it uses an alkaline reagent to adjust the pH for precipitation, which is precise, rapid, and easy to operate, thereby simplifying the overall process. The total processing time is reduced to 6-8 hours.

[0018] The method provided by this invention has a total copper recovery rate of ≥99%, a copper purity of ≥99.8%, and the recovered copper can be directly used in the electronics industry, resulting in high added value.

[0019] The method provided by this invention has a processing cost of 700~1000 yuan / m³. 3 The copper recovery value of the waste liquid is 1500~2200 yuan / m³. 3 Waste liquid, net profit of 800~1200 yuan / m³ 3 Waste liquid, with significant economic benefits.

[0020] The method provided by this invention produces no secondary pollution and generates little solid waste; the effluent quality is excellent and can meet the reuse standards; the ruthenium-iridium-titanium electrode has a long service life (>10 years) and is free from heavy metal pollution.

[0021] The method and equipment provided by this invention have high reliability, the ruthenium-iridium-titanium electrode has strong corrosion resistance, and the maintenance cost is low; it has a high degree of automation and good operational stability; it is suitable for continuous industrial production.

[0022] In summary, the electrochemical oxidation and high-value copper recovery method for chemical copper plating waste liquid provided by this invention is characterized by high efficiency, economy, and environmental protection. Detailed Implementation

[0023] This invention provides a method for electrochemical oxidation and high-value copper recovery of chemical copper plating wastewater, comprising the following steps: The chemical copper plating waste liquid is pretreated to obtain pretreated waste liquid. The pretreatment reagents include acid reagents and redox substances. The pretreated waste liquid was electrochemically oxidized using a ruthenium-iridium-titanium electrode to obtain the electrolyzed waste liquid; The waste liquid after electrolysis was mixed with an alkaline reagent to carry out a precipitation reaction, and then solid-liquid separation was performed to obtain Cu(OH)2 precipitate; The Cu(OH)2 precipitate was dissolved in acid to obtain a copper ion solution; The copper ion solution was purified by solvent extraction using LIX984N extractant to obtain a copper-loaded organic phase. The copper-loaded organic phase was back-extracted with an acid solution to obtain a pure copper ion solution. The pure copper ion solution is used as an electrolyte for electrodeposition to recover metallic copper products.

[0024] In this invention, unless otherwise specified, all raw materials / components used in the preparation are commercially available products well known to those skilled in the art.

[0025] This invention pretreats the chemical copper plating wastewater to obtain a pretreated wastewater. The pretreatment reagents include acid reagents and redox substances. In this invention, the chemical copper plating wastewater can be PCB chemical copper plating wastewater. The concentration of copper ions in the chemical copper plating wastewater can be 5000~15000 mg / L, and in the example, it can be 8500 mg / L. The chemical copper plating wastewater also contains EDTA, formaldehyde, and bipyridine; the concentration of EDTA in the chemical copper plating wastewater can be 10000~15000 mg / L, and in the example, it can be 12000 mg / L. The concentration of formaldehyde in the chemical copper plating wastewater can be 2000~3000 mg / L, and in the example, it can be 2500 mg / L. The concentration of bipyridine in the chemical copper plating wastewater can be 500~1000 mg / L, and in the example, it can be 800 mg / L. The COD value of the chemical copper plating wastewater can be 25,000~30,000 mg / L, and in this example it can be 28,000 mg / L. The pH value of the chemical copper plating wastewater can be 10~13, and in this example it is 12.3.

[0026] In this invention, the pretreatment preferably includes the following steps: The chemical copper plating waste liquid is filtered to obtain a filtrate. The mesh size of the filter used for filtration can be 200 mesh. This invention preferably removes suspended solids and insoluble impurities from the chemical copper plating waste liquid through filtration. The pH of the filtrate is adjusted to 2-3 using an acid reagent, which in this embodiment can be 2.5±0.1. The acid reagent is a sulfuric acid solution, resulting in an acidic waste liquid. The mass content of H2SO4 in the sulfuric acid solution is preferably 98%. This invention mixes the acidic waste liquid with a redox substance, preferably an H2O2 solution. The H2O2 content in the H2O2 solution is preferably 20-35 wt%, and the amount (volume of the redox substance) of the redox substance is preferably 0.3-0.8% of the volume of the chemical copper plating waste liquid, which in this embodiment can be 0.5%, resulting in a pretreated waste liquid.

[0027] After obtaining the pretreated waste liquid, the present invention electrochemically oxidizes the pretreated waste liquid using a ruthenium-iridium-titanium electrode (also known as a ruthenium-iridium-titanium composite oxide electrode, Ti / RuO2-IrO2) to obtain the electrolyzed waste liquid. In the present invention, the ruthenium-iridium-titanium electrode preferably comprises RuO2 and IrO2, and the molar ratio of RuO2 to IrO2 is preferably 30~70:70~30, which can be 1:1 or 2:3 in the embodiments. The electrochemical oxidation preferably uses the ruthenium-iridium-titanium electrode as the anode, and preferably uses a titanium plate as the cathode. The electrode spacing between the anode and cathode is preferably 10~20 mm, which can be 15 mm in the embodiments. The electrochemical oxidation conditions preferably include a current density of 80~150 mA / cm². 2 In the embodiment, it can be 120 mA / cm 2 Or 150 mA / cm 2 The preferred cell voltage is 2.0~3.5V, and in this embodiment it can be 2.8V. The preferred electrolysis time is 2~4h, and in this embodiment it can be 3h or 4h. The preferred electrolysis temperature is 30~50℃, and in this embodiment it can be 40±2℃; the preferred effective electrode area is 2m². 2 / m 3 Waste liquid. During the electrochemical oxidation process, the present invention preferably continuously monitors COD changes, and stops electrochemical oxidation when COD degrades to below 2500 mg / L.

[0028] In this invention, the reaction mechanism of the electrochemical oxidation is as follows: Anode reaction: H₂O → ·OH + H₂ + +e - ; ·OH + organic complex → CO2 + H2O + inorganic ions; Copper complex release: Cu-EDTA + ·OH → Cu 2+ +Degradation products.

[0029] After obtaining the electrolytic waste liquid, the present invention mixes the electrolytic waste liquid with an alkaline reagent to carry out a precipitation reaction, followed by solid-liquid separation to obtain Cu(OH)2 precipitate. In the present invention, the alkaline reagent is an alkali metal hydroxide, preferably including sodium hydroxide and / or potassium hydroxide. In the embodiments, the alkaline reagent can be a sodium hydroxide solution. The mass content of NaOH in the sodium hydroxide solution is preferably 25-32%.

[0030] In this invention, the preferred conditions for the precipitation reaction include: a pH value of 9-10.5, preferably 9.5 ± 0.2 in the examples; a pH value accuracy of ± 0.2; a reaction temperature of 25-40°C; and a reaction time of 30-60 min, preferably 45 min in the examples. The precipitation reaction is preferably carried out under stirring conditions, with a stirring speed of 100-200 rpm, preferably 150 rpm in the examples. The mixing of the electrolytic waste liquid and the alkaline reagent preferably involves adding the alkaline reagent to the electrolytic waste liquid. The addition rate of the alkaline reagent is preferably 10-30 mL / min·m. 3 In the examples, the flow rate can be 20 mL / min·m 3 This invention avoids localized overheating by controlling the rate at which the alkaline reagent is added.

[0031] In this invention, copper ions in the waste liquid after electrolysis during the precipitation reaction form Cu(OH)2 precipitate: Cu 2+ +2OH - →Cu(OH)2↓.

[0032] In this invention, the precipitation reaction further includes a flocculant. Preferably, when the precipitation reaction also includes a flocculant, the present invention preferably involves mixing the electrolytic waste liquid and an alkaline reagent for a preliminary reaction to obtain a preliminary reaction solution, and then mixing the preliminary reaction solution with the flocculant to continue the reaction. The flocculant can be polyacrylamide (PAM). The mass of the flocculant is preferably 0.5~2 mg / L of the volume of the electroless copper plating waste liquid, and in the examples, it can be 1 mg / L. The continued reaction time is preferably 1~3 hours, and in the examples, it can be 2 hours. The continued reaction is preferably allowed to settle. The present invention preferably adds a flocculant to promote precipitation and aggregation.

[0033] In this invention, the solid-liquid separation can be performed by gravity sedimentation or pressure filtration. The pressure filtration can be performed using a plate and frame filter press. The pressure for the pressure filtration is preferably 0.5~0.7 MPa, and in this embodiment, it can be 0.6 MPa. The solid-liquid separation yields Cu(OH)2 precipitate and supernatant. The organic matter in the supernatant is essentially mineralized, and the COD is reduced to below 500 mg / L. The water content of the Cu(OH)2 precipitate can be 50~70%, and in this embodiment, it can be 60%. The preferred yield of the Cu(OH)2 precipitate is 35~45 kg / m³. 3 Waste liquid. The supernatant may have a liquid COD of 420 mg / L and Cu. 2+ <5mg / L.

[0034] After obtaining Cu(OH)₂ precipitate, the present invention dissolves the Cu(OH)₂ precipitate in acid to obtain a copper ion solution. In the present invention, the water content of the Cu(OH)₂ precipitate can be 50-70%; the acid dissolution is preferably carried out using sulfuric acid solution. The mass content of H₂SO₄ in the sulfuric acid solution is preferably 10-15%, and in the example it can be 12%. The pH value of the copper ion solution is preferably 1.5-2.5, and in the example it can be 2.0±0.1. The concentration of copper ions in the copper ion solution is preferably 40-60 g / L, and in the example it can be 48 g / L. After acid dissolution, an initial crude solution is directly obtained. The present invention preferably filters the initial crude solution, and the filtrate obtained is a copper ion solution. The present invention preferably removes insoluble impurities through filtration.

[0035] After obtaining the copper ion solution, the present invention uses LIX984N extractant for solvent extraction purification to obtain a copper-loaded organic phase. In this invention, the LIX984N extractant is preferably a LIX984N-kerosene system. The LIX984N-kerosene system preferably includes LIX984N, isodecanol, and sulfonated kerosene. The volume content of LIX984N in the LIX984N-kerosene system is 10-30%, which can be 20% in the examples; the volume content of isodecanol is 5-15%, which can be 5% in the examples; and the volume content of sulfonated kerosene is 60-75%, which can be 75% in the examples.

[0036] The preferred conditions for solvent extraction purification include: an O / A ratio of 1.5 to 2.5:1, which can be 2:1 in the examples. The preferred number of extraction stages is 3 to 4. The preferred contact time per stage is 5 to 10 minutes, which can be 8 minutes in the examples. The preferred phase separation time is 3 to 5 minutes. By controlling the extraction parameters during the solvent extraction purification process, the copper extraction rate is ≥99.5%, achieving efficient separation of copper from other impurity ions.

[0037] In this invention, the solvent extraction and purification also yields an aqueous phase after extraction. The aqueous phase after extraction (i.e., the raffinate) contains Cu. 2+ <150mg / L.

[0038] After obtaining the copper-loaded organic phase, the present invention performs back-extraction on the copper-loaded organic phase using an acid solution to obtain a pure copper ion solution. In this invention, the acid solution used for back-extraction can be a sulfuric acid solution. The mass content of H₂SO₄ in the sulfuric acid solution is preferably 2-3 mol / L, and in the examples, it can be 2.5 mol / L. The number of back-extraction stages is preferably 2-3 stages. The concentration of copper ions in the pure copper ion solution is preferably 45-55 g / L.

[0039] After obtaining a pure copper ion solution, this invention uses the pure copper ion solution as an electrolyte for electrowinning to recover metallic copper. In this invention, the electrowinning recovery preferably uses 316L stainless steel as the cathode and a lead-tin alloy as the anode. The preferred conditions for the electrowinning recovery include: the electrowinning solution composition preferably includes CuSO4 and H2SO4, and the electrowinning solution preferably includes CuSO4, H2SO4, and water; the concentration of CuSO4 in the electrowinning solution is preferably 150-200 g / L, and in the example, it can be 180 g / L; the concentration of H2SO4 in the electrowinning solution is preferably 30-60 g / L, and in the example, it can be 50 g / L; and the preferred current density is 250-350 mA / cm². 2 In the embodiment, it can be 300 mA / cm 2 The cell voltage is preferably 2~2.5V. The electrowinning temperature is 40~60℃, which can be 55℃ in the embodiment, and the electrowinning time is preferably 3~12h, which can be 8h in the embodiment. The copper product can be a high-purity copper plate. The purity of the high-purity copper plate is preferably ≥99.8%.

[0040] In this invention, the solid-liquid separation further yields a supernatant. The solvent extraction and purification further yields an aqueous phase after extraction. Preferably, this invention further includes: combining the supernatant and the aqueous phase after extraction and then performing physical adsorption, wherein the fine physical adsorption is carried out using activated carbon. The effluent after physical adsorption has the following parameters: COD < 50 mg / L, Cu 2+ <0.5mg / L.

[0041] The present invention also provides an apparatus for the electrochemical oxidation and high-value copper recovery method of chemical copper plating waste liquid, comprising a pretreatment device, a ruthenium-iridium-titanium electrode electrochemical reactor, a pH-adjusting precipitation tank, a solid-liquid separation device, an extraction separation system, and an electrowinning recovery device connected in sequence.

[0042] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0043] Example 1 This embodiment provides a method for electrochemical oxidation and high-value copper recovery of chemical copper plating wastewater: The original composition of the PCB chemical copper plating waste liquid treated in this embodiment includes: Cu 2+ 8500 mg / L; EDTA: 12000 mg / L; Formaldehyde: 2500 mg / L; Bipyridine: 800 mg / L; COD: 28000 mg / L; pH: 12.3; Processing capacity: 10 m³ 3 / d; Detailed operation steps: (1) Pretreatment: The waste liquid was filtered through a 200-mesh filter to remove suspended solids; the pH was adjusted to 2.5±0.1 with 98% H2SO4; 30% H2O2 solution was added, with the volume of H2O2 solution added being 0.5% of the volume of the PCB chemical copper plating waste liquid; and the reaction was carried out at 25℃ for 30 minutes. (2) Electrochemical oxidation: The anode is Ti / RuO2-IrO2 (RuO2 to IrO2 (ruthenium-iridium) molar ratio is 1:1), and the cathode is pure titanium; the electrode spacing is 15 mm, and the effective electrode area is 2 m². 2 / m 3 Waste liquid; current density 120 mA / cm² 2 The cell voltage was 2.8V; electrolysis lasted for 3 hours, with the temperature controlled at 40±2℃; COD changes were continuously monitored until it was degraded to below 2500mg / L. (3) Alkali precipitation: Adjust the pH to 9.5 ± 0.2 by adding 32% NaOH solution; control the addition rate of NaOH solution at 20 mL / min·m. 3 To avoid localized overheating; the stirring speed is 150 rpm, and the reaction time is 45 min; add 1 mg / L of PAM flocculant and let it stand for 2 h to settle; (4) Solid-liquid separation: The filter cake is separated using a plate and frame filter press at a pressure of 0.6 MPa; the moisture content of the Cu(OH)2 filter cake is 60%, and the yield is approximately 40 kg / m³. 3 Waste liquid; filtrate COD is 420 mg / L, Cu 2+ <5mg / L; (5) Acid dissolution: Dissolve the Cu(OH)₂ filter cake in 12% H₂SO₄; control the pH of the solution to 2.0 ± 0.1. 2+ Concentration 48 g / L; filtration to remove insoluble matter to obtain a clear CuSO4 solution; (6) Solvent extraction: Extractant: 20% LIX984N + 5% isodecanol + 75% sulfonated kerosene; Extraction conditions: O / A = 2:1, 3-stage extraction, 8 min contact per stage; Extraction rate: 99.7%, raffinate Cu 2+ <150mg / L; (7) Back-extraction electrowinning: Back-extraction agent: 2.5M H2SO4, back-extraction stage 2; Electrowinning solution composition: CuSO4 180g / L, H2SO4 50g / L; Electrowinning conditions: current density 300 mA / cm² 2 The preferred cell voltage is 2V, and the temperature is 55℃; electrowinning lasts for 8 hours, yielding a copper plate thickness of 2~3mm and a purity of 99.85%. Processing effect and analysis in this embodiment: Pollutant removal efficiency: COD: 28000→35mg / L, removal rate 99.9%; Cu 2+ : 8500→0.2mg / L, removal rate 99.998%; EDTA: completely mineralized into CO2, H2O and inorganic salts; Resource recycling effect: Electrolytic copper recovery: 8.1 kg / m³ 3 Waste liquid, purity 99.85%; copper recovery rate: 99.2%; no solid waste generated (except for a small amount of insoluble impurities); Environmental benefits: The final effluent meets the Class I standard of the Integrated Wastewater Discharge Standard; the solid waste reduction rate is >95%; and there is no secondary pollution from heavy metals.

[0044] Example 2: Treatment of high-concentration electroless copper plating concentrate This embodiment provides a method for electrochemical oxidation and high-value copper recovery of chemical copper plating wastewater: The original composition of the typical PCB chemical copper plating waste liquid treated in this embodiment includes: Cu 2+ : 15200 mg / L; Potassium sodium tartrate: 18000 mg / L; COD: 45000 mg / L; pH: 11.2; Process parameters adjusted compared to Example 1: Electrolysis time extended to 4 hours; current density increased to 150 mA / cm² 2 The number of extraction stages has been increased to 4. Processing effect: COD removal rate: 97.5%; copper recovery rate: 99.5%; recovered copper purity: 99.9%.

[0045] As can be seen from the above embodiments, the electrochemical oxidation and high-value copper recovery method for chemical copper plating waste liquid provided by the present invention can achieve the following effects: organic complex mineralization rate: ≥95%; COD removal rate: ≥90%; copper recovery rate: ≥99%; recovered copper purity: ≥99.8%; total treatment time: 6~8h.

[0046] The electrochemical oxidation and high-value copper recovery method for chemical copper plating wastewater provided by this invention employs a ruthenium-iridium-titanium composite oxide electrode, which has a high oxygen evolution potential and strong oxidation capacity; direct electrochemical oxidation eliminates the need for Fenton's reagent, simplifying the process and reducing solid waste generation; precise pH control is achieved using sodium hydroxide adjustment, resulting in fast reaction speed and high control accuracy; and the method integrates electrochemical oxidation, precipitation separation, extraction purification, and electrowinning recovery into a unified recovery method. The method provided by this invention has the following advantages: high processing efficiency: single electrochemical oxidation achieves over 95% complex mineralization; long equipment life: the ruthenium-iridium-titanium electrode has a lifespan of >10 years; good economic benefits: resource recovery significantly exceeds processing costs; environmentally friendly: no heavy metal pollution and low solid waste generation.

[0047] The method provided by this invention has the advantages of high efficiency, economy and environmental protection. It realizes the complete mineralization of organic pollutants and the high-value recovery of copper resources. It is applicable to the treatment of various chemical copper plating waste liquids and can be extended to related industries such as electroplating and electronic materials. It meets the requirements of circular economy and clean production, and is of great significance to promoting the green development of the electronic circuit industry. It has good industrialization prospects.

[0048] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. Other embodiments can be obtained based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for electrochemical oxidation and high-value copper recovery of chemical copper plating wastewater, characterized in that, Includes the following steps: The chemical copper plating waste liquid is pretreated to obtain pretreated waste liquid. The pretreatment reagents include acid reagents and redox substances. The pretreated waste liquid was electrochemically oxidized using a ruthenium-iridium-titanium electrode to obtain the electrolyzed waste liquid; The waste liquid after electrolysis was mixed with an alkaline reagent to carry out a precipitation reaction, and then solid-liquid separation was performed to obtain Cu(OH)2 precipitate; The Cu(OH)2 precipitate was dissolved in acid to obtain a copper ion solution; The copper ion solution was purified by solvent extraction using LIX984N extractant to obtain a copper-loaded organic phase. The copper-loaded organic phase was back-extracted with an acid solution to obtain a pure copper ion solution. The pure copper ion solution is used as an electrolyte for electrodeposition to recover metallic copper products.

2. The method for electrochemical oxidation and high-value copper recovery of chemical copper plating waste liquid according to claim 1, characterized in that, The pretreatment includes the following steps: filtering the electroless copper plating waste liquid to obtain a filtrate; adjusting the pH of the filtrate to 2-3 using an acid reagent, wherein the acid reagent is a sulfuric acid solution, to obtain an acidic waste liquid; mixing the acidic waste liquid with an oxidizing and reducing agent, wherein the oxidizing and reducing agent is an H2O2 solution, wherein the H2O2 content in the H2O2 solution is 20-35 wt%, and the amount of the oxidizing and reducing agent accounts for 0.3-0.8% of the volume of the electroless copper plating waste liquid, to obtain a pretreated waste liquid.

3. The method for electrochemical oxidation and high-value copper recovery of chemical copper plating waste liquid according to claim 1, characterized in that, The ruthenium-iridium-titanium electrode comprises RuO2 and IrO2, wherein the molar ratio of RuO2 to IrO2 is 30~70:70~30; the electrochemical oxidation uses the ruthenium-iridium-titanium electrode as the anode and a titanium plate as the cathode. The conditions for the electrochemical oxidation include a current density of 80–150 mA / cm². 2 The cell voltage is 2.0~3.5V, the electrolysis time is 2~4h, and the electrolysis temperature is 30~50℃.

4. The method for electrochemical oxidation and high-value copper recovery of chemical copper plating waste liquid according to claim 1, characterized in that, The alkaline reagent is an alkali metal hydroxide; the conditions for the precipitation reaction include: pH value of 9~10.5; pH value accuracy of ±0.2; reaction temperature of 25~40℃; time of 30~60min; and the precipitation reaction is carried out under stirring conditions.

5. The method for electrochemical oxidation and high-value copper recovery of chemical copper plating waste liquid according to claim 1 or 4, characterized in that, The precipitation reaction also includes a flocculant, the mass of which accounts for 0.5~2 mg / L of the volume of the chemical copper plating waste liquid.

6. The method for electrochemical oxidation and high-value copper recovery of chemical copper plating waste liquid according to claim 1, characterized in that, The Cu(OH)2 precipitate has a water content of 50-70%; the acid dissolution uses sulfuric acid solution, and the mass content of H2SO4 in the sulfuric acid solution is 10-15%; the pH value of the copper ion solution is 1.5-2.5; and the concentration of copper ions in the copper ion solution is 40-60 g / L.

7. The method for electrochemical oxidation and high-value copper recovery of chemical copper plating waste liquid according to claim 1, characterized in that, The LIX984N extractant is a LIX984N-kerosene system; the solvent extraction and purification conditions include: an O / A ratio of 1.5~2.5:1, 3~4 extraction stages, a contact time of 5~10 min per stage, and a phase separation time of 3~5 min.

8. The method for electrochemical oxidation and high-value copper recovery of chemical copper plating waste liquid according to claim 1, characterized in that, The acid solution used in the back-extraction is a sulfuric acid solution, and the mass content of H2SO4 in the sulfuric acid solution is 2~3 mol / L; the number of back-extraction stages is 2~3 stages; and the concentration of copper ions in the pure copper ion solution is 45~55 g / L.

9. The method for electrochemical oxidation and high-value copper recovery of chemical copper plating waste liquid according to claim 1, characterized in that, The electrodeposition recovery process uses 316L stainless steel as the cathode and a lead-tin alloy as the anode. The electrodeposition recovery conditions include: the electrolyte composition consists of CuSO4 and H2SO4, and the current density is 250~350 mA / cm². 2 The cell voltage is 2~2.5V, the electrowinning temperature is 40~60℃, and the electrowinning time is 3~12h; the copper product is a high-purity copper plate with a purity ≥99.8%.

10. The method for electrochemical oxidation and high-value copper recovery of chemical copper plating waste liquid according to claim 1, characterized in that, The solid-liquid separation also yields a supernatant, and the solvent extraction and purification also yields an aqueous phase after extraction; further comprising: combining the supernatant and the aqueous phase after extraction and then performing physical adsorption, wherein the physical fine adsorption is carried out using activated carbon, and the effluent after physical adsorption has the following parameters: COD < 50 mg / L, Cu 2+ <0.5mg / L.