Process for extracting copper from low-copper-content waste liquid and treating wastewater

Abstract

The invention discloses a process for extracting copper from low-copper-content waste liquid and treating wastewater, and relates to the field of circuit board production waste liquid treatment.The process sequentially comprises the specific steps of waste liquid mixing, electrolytic additive adding, circulating mixing, electrolytic copper extraction, copper ion concentration detection and wastewater treatment. Meanwhile, the equipment universality is high, copper-containing complexes can be degraded, up-to-standard discharge of wastewater can be easily achieved, elemental copper generated in the electrolysis process has certain economic benefits, and the method is suitable for application and popularization.

Description

Technical Field

[0001] The present invention relates to the technical field of waste liquid treatment for circuit boards, and particularly belongs to a copper extraction and wastewater treatment process for low copper-containing waste liquid. Background Art

[0002] During the production process of circuit boards, a large amount of low copper waste liquid with various types and different quantities will be generated, such as micro-etching solution, brownification solution, copper bath water, stripping solution (copper nitrate), medium roughening solution, super roughening solution, etc. In the prior art, these low copper waste liquids usually need to be treated separately, with high equipment and operation costs. Moreover, some low copper waste liquids cannot extract copper alone, and the wastewater cannot be degraded, so they need to be outsourced for treatment, resulting in high costs.

[0003] The disadvantages of the prior art include:

[0004] Poor equipment versatility: The prior art can only treat a single type of low copper waste liquid and cannot centrally treat multiple waste liquids, making it difficult in terms of equipment investment and operation management.

[0005] Complex treatment process: The prior art requires pre-treating and filtering the waste liquid first and then extracting copper, with a complex process and low efficiency.

[0006] Unable to treat complex copper waste liquid: The prior art cannot effectively treat the waste liquid containing complex copper, resulting in the inability to degrade the organic complex waste liquid and the need for outsourcing treatment, increasing costs.

[0007] Therefore, there is an urgent need for a copper extraction and wastewater treatment process that can centrally treat multiple low copper waste liquids, simplify the treatment process, and reduce costs. Summary of the Invention

[0008] The purpose of the present invention is to provide a copper extraction and wastewater treatment process for low copper-containing waste liquid, which solves the problems in the prior art such as poor equipment versatility, complex treatment process, and inability to treat complex copper waste liquid, and realizes the centralized treatment of multiple low copper waste liquids, the efficient recovery of copper, and the up-to-standard discharge of wastewater.

[0009] The technical solution adopted by the present invention is as follows:

[0010] A copper extraction and wastewater treatment process for low copper-containing waste liquid, characterized by comprising the following steps:

[0011] S1: Mix multiple low copper waste liquids in a certain proportion, and the low copper waste liquids include at least two of micro-etching solution, brownification solution, copper bath water, stripping solution, medium roughening solution, and super roughening solution;

[0012] S2: Introduce the mixed waste liquid into an electrolytic cell and add an electrolytic additive to the electrolytic cell;

[0013] S3: Start the circulation system to make the waste liquid circulate and mix in the electrolytic cell for 30 minutes;

[0014] S4: Turn on the power supply for electrolysis;

[0015] S5: When the copper ion concentration in the waste liquid drops to 3 - 5 g / L, stop electrolysis and pump the electrolyte into the storage tank for storage;

[0016] S6: Carry out acid - base neutralization, precipitation and filtration on the waste liquid after electrolysis.

[0017] In the scheme, through the method of mixing various low - copper waste liquids, the high oxidizing property of some low - copper waste liquids can be utilized to destroy the copper - containing complex, making copper ions free, improving the subsequent electrolysis effect, reducing the dosage of electrolysis additives. The setting of electrolysis additives is used to improve the conductivity of the electrolyte, promote the dissolution of copper ions at the same time, facilitate electrolytic separation, and further destroy the copper - containing complex. During the mixing process, the electrolysis additives and low - copper waste liquid can be fully mixed to ensure the electrolysis effect. The limitation that the copper ion concentration drops to 3 - 5 g / L enables the ammonia nitrogen and COD after electrolysis to be reduced to 10 - 20% of the original waste liquid. After only acid - base neutralization, precipitation and filtration, the wastewater can be treated without outsourcing to large - scale industrial waste liquid treatment equipment. The treatment process is simple, the required equipment is unified and the cost is low. Not only the treatment cost of the waste liquid is reduced, but also the elemental copper during the electrolysis process can generate certain benefits, improving the economic benefits.

[0018] Preferably, the electrolysis additive in step S2 is a mixed solution of sulfuric acid, sodium chloride and thiourea, where the mass ratio of sulfuric acid, sodium chloride and thiourea is 16 - 20:2:1. In the scheme, a mixed solution of sulfuric acid, sodium chloride and thiourea is used as the electrolysis additive. Among them, sulfuric acid can adjust the pH value of the electrolyte, sodium chloride can provide chloride ions to generate chlorine to destroy the complex, and thiourea is used to improve the compactness of the electrolytically deposited copper, making the deposited copper elemental adhere tightly and reducing the waste of the electrode. Using the above electrolysis additive, the specific reactions are as follows:

[0019] Anode: Cl - +OH - +NO3 - -e - powered by electricity-Cl2↑+O2↑+O+N2↑

[0020] Cathode: Cu 2+ +Cu - +e - powered by electricity-Cu↓

[0021] Complex - breaking reaction: Cl2+O2+O+organic matter (complex)--low - chain organic matter+N2↑+reduction of ammonia nitrogen+reduction of COD

[0022] In this way, the copper - containing waste liquid is broken - complexed and electrolyzed.

[0023] Preferably, in step S2, the electrolytic additive is added to a pH value of 1.8-3. When the pH value is controlled in the range of 1.8-3, copper ions (Cu 2+ ) exists in a free state and is easily reduced to elemental copper at the cathode. In addition, the acidic environment helps to improve the conductivity of the electrolyte and reduce the energy consumption of electrolysis. At the same time, the acidic conditions can inhibit the formation of precipitates such as copper hydroxide (Cu(OH)2), avoid the loss of copper ions during the electrolysis process, and improve the electrolytic separation effect.

[0024] Preferably, in step S3, the circulation system is a circulation pump, and the circulation pump is connected to the electrolytic cell. The circulation pump is used to ensure mixing between the copper-containing waste liquids, and mixing between the electrolysis additive and the copper-containing waste liquid, and electrolysis is performed after the complex is fully broken, thereby shortening the electrolysis time and reducing the cost.

[0025] Preferably, in step S5, the waste liquid in the electrolytic cell is sampled every 30 minutes, and the copper ion concentration is detected using a spectrophotometer until the copper ion concentration in the waste liquid drops to 3-5 g / L. The spectrophotometer detection method has low cost, does not require large-scale equipment, and is suitable for industrial applications.

[0026] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0027] 1. Centralized treatment of multiple low-copper waste liquids: By mixing multiple low-copper waste liquids in a certain proportion, centralized treatment of multiple waste liquids is achieved, reducing equipment investment and difficulty in operation and management.

[0028] 2. Efficient copper extraction: Through electrolytic additives and electrolytic processes, efficient copper recovery is achieved, and the copper ion concentration can be reduced to 3-5g / L.

[0029] 3. Wastewater discharge meets the standards: The waste liquid after electrolysis is treated by acid-base neutralization, precipitation and filtration, and the wastewater can be directly discharged into the wastewater station for further treatment, reducing the cost of wastewater treatment.

[0030] 4. Significant economic benefits: Each ton of waste liquid can increase revenue by more than 3,000 yuan, which has significant economic benefits. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below through embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the embodiments described are only part of the embodiments of the present invention, rather than all the embodiments. The groups and embodiments of the present invention generally shown can be arranged and designed in various different configurations.

[0032] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0033] It should be noted that relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising one..." does not exclude the presence of additional identical elements in the process, method, article or device including the said element.

[0034] Example 1: A process for copper extraction and wastewater treatment from low copper-containing waste liquid, comprising the following steps:

[0035] Waste liquid mixing: Mix the micro-etching solution, brownification solution, and copper bath water in a ratio of 1:1:1 to obtain a mixed waste liquid.

[0036] Addition of electrolysis additive: Introduce the mixed waste liquid into an electrolytic cell, and add an electrolysis additive to the electrolytic cell. The electrolysis additive is a mixed solution of sulfuric acid, sodium chloride, and thiourea, where the mass ratio of sulfuric acid, sodium chloride, and thiourea is 18:2:1. By controlling the amount of the electrolysis additive, adjust the pH value of the electrolyte to 2.5.

[0037] Circulating mixing: Turn on the circulation pump to circulate and mix the waste liquid in the electrolytic cell for 30 minutes.

[0038] Electrolytic copper extraction: Turn on the power supply for electrolysis, and set the corresponding current according to the copper ion concentration in the waste liquid.

[0039] Detection of copper ion concentration: Take samples of the waste liquid in the electrolytic cell every 30 minutes, and use a spectrophotometer to detect the copper ion concentration. When the copper ion concentration in the waste liquid drops to 4 g / L, stop electrolysis, and pump the electrolyte into a storage tank for storage.

[0040] Wastewater treatment: Carry out acid-base neutralization, precipitation, and filtration treatment on the electrolyzed waste liquid. The treated wastewater can be directly discharged into the wastewater treatment station for further treatment.

[0041] As can be seen from the above, the solution of the present application reduces the processing cost and waste of resources through the hybrid processing method. At the same time, the equipment has strong versatility and a simple processing flow, can perform post-treatment on the decomposed copper complex, and is easy to achieve the standard discharge of wastewater.

[0042] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A process for extracting copper from low-copper wastewater and treating wastewater, characterized in that: The following steps are involved: S1: mixing a plurality of low-copper waste liquids in a certain proportion, wherein the low-copper waste liquids include at least two of micro-etching liquid, browning liquid, copper tank water, deplating liquid, medium-roughening liquid and super-roughening liquid; S2: introducing the mixed waste liquid into an electrolytic cell and adding an electrolytic additive to the electrolytic cell; S3: Start the circulation system to circulate and mix the waste liquid in the electrolytic tank for 30 minutes; S4: Turn on the power supply to perform electrolysis; S5: When the copper ion concentration in the waste liquid drops to 3-5 g / L, the electrolysis is stopped and the electrolyte is pumped into a storage tank for storage; S6: The waste liquid after electrolysis is subjected to acid-base neutralization, precipitation and filtration treatment.

2. A process for extracting copper from low-copper waste liquid and treating wastewater according to claim 1, characterized in that: The electrolytic additive in step S2 is a mixed solution of sulfuric acid, sodium chloride and thiourea, wherein the mass ratio of sulfuric acid, sodium chloride and thiourea is 16-20:2:

1.

3. A process for extracting copper from low-copper waste liquid and treating wastewater according to claim 2, characterized in that: In step S2, the electrolytic additive is added to a pH value of 1.8-3.

4. A process for extracting copper from low-copper waste liquid and treating wastewater according to claim 1, characterized in that: In step S3, the circulation system is a circulation pump, and the circulation pump is connected to the electrolytic cell.

5. A process for extracting copper from low-copper wastewater and treating wastewater according to any one of claims 1 to 4, characterized in that: In step S5, the waste liquid in the electrolytic cell is sampled every 30 minutes, and the copper ion concentration is detected using a spectrophotometer until the copper ion concentration in the waste liquid drops to 3-5 g / L.