Process for comprehensively recycling micro-etching waste liquid

Abstract

The invention relates to a process for comprehensively recycling a micro-etching waste liquid, which adopts a basic copper chloride crude product to adjust the pH value, can utilize sulfuric acid in the micro-etching waste liquid to prepare electroplating-grade copper sulfate, reduces the consumption of sulfuric acid, improves the additional value of the basic copper chloride crude product, and obtains the electroplating-grade copper sulfate with high additional value. In the whole process, only the oxidizing agent hydrogen peroxide is added, concentrated sulfuric acid is used as a catalyst, organic matters are converted into carbon dioxide, the process is green and environment-friendly, secondary pollution cannot be caused, the quality of the product crystal copper sulfate can reach the electroplating pure grade index, anion sulfate radicals are finally produced in the form of sodium sulfate, and the requirements of national standard sodium sulfate products are met. In the whole treatment process, the only discharged crystal fraction condensate needs to be subjected to biochemical treatment and then directly meets the wastewater discharge standard, and the trouble of subsequent wastewater treatment is avoided. In addition, the process is simple to operate, easy to implement and wide in application range.

Description

technical field [0001] The invention relates to the field of waste liquid recycling, in particular to a process for preparing electroplating-grade copper sulfate by using micro-etching waste liquid. Background technique [0002] PCB (Printed Circuit Board), the Chinese name is printed circuit board, also known as printed circuit board, printed circuit board, is an important electronic component, a support body for electronic components, and a provider of electrical connections for electronic components. There are more than 20 production processes of PCB, among which the pretreatment of many processes must be micro-etched, such as copper immersion (PTH) process, inner layer pretreatment, thick copper (PATT) production line, pattern plating (PLAT) process, green Oil pretreatment, OSP treatment, etc., all need to use micro-etching liquid to remove the oxide layer on the copper surface to form a certain roughness on the surface, thereby increasing the bonding force between the c...

AI Technical Summary

Problems solved by technology

[0003] At this stage, the environmental protection industry has fully studied the etching waste liquid produced in the process of printed circuit boards, but the micro-etching waste liquid generally contains copper in the range of 2000PPM to 20000PPM, and has high organic matter, complex ions, COD (generally Unfavorable factors such as 7000PPM-30000PPM), sodium ions (generally 0PPM-10000PPM), although there are research processes, they are limited to the electrolytic recovery of copper, and the products are almost only blister copper, sponge copper or copper mud, which cannot be used for micro The environmental pollution factors in the etching waste liquid are thoroughly treated, and a large amount of sulfate radicals are discharged to the environment in the form of sodium sulfate soluble salts

[0004] The copper in the micro-etching solution is recovered by electrolysis. Due to the presence of harmful elements in the micro-etching solution, the recovered cathode copper is usually of poor quality. After electrolysis, the residual solution still needs to be neutralized by adding alkali, which contains COD, The organic matter cannot be separated and removed; the method of directly adding alkali to neutralize the precipitation can recover the copper in the micro-etching solution, but the product copper oxide is also difficult to filter, the purity is not good, and the need to discharge soluble sodium sulfate waste salt to the environment ; The use of electrodialysis and other processes will also greatly reduce the service life of the dialysis membrane group due to the corrosion ability of the soluble organic matter in the micro-etching solution under strong acidic conditions, resulting in high production costs for stable maintenance of the system

[0005] Invention patent application CN109678196A, the organic matter in the micro-etching waste liquid is removed by extraction, and then activated carbon is used to absorb the organic matter, which leads to a large amount of activated carbon waste residue, which can only be landfilled, and the treatment cost is too high

[0006] Due to the low value and high hazard of micro-etching waste liquid, the existing resource disposal methods of micro-etching waste liquid cannot meet the increasingly stringent environmental protection requirements, and there is a shortcoming that anion sulfate radicals are discharged to the surrounding environment in the form of soluble salts. , there is an urgent need for a near-zero emission disposal technology / process with simple disposal process, low investment cost, and comprehensive resource utilization of anions and cations to fill this gap

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