Recycling method and system of PCB (printed circuit board) etching waste liquid

Abstract

The invention discloses a recycling method and system of a PCB (printed circuit board) etching waste liquid. The method adopts a technical process of diffusion dialysis, catalytic oxidation, bipolar membrane, evaporative crystallization and recrystallization, and comprises the following steps: sequentially passing the acidic chlorine-type copper etching waste liquid through a treatment system composed of a diffusion dialyzer, a catalytic oxidation device, a bipolar membrane dialyzer and an evaporative crystallizer to finally obtain crude copper sulfate crystals, and recrystallizing the crude copper sulfate crystals to obtain the commercially available high-purity copper sulfate. In the meanwhile, the hydrochloric acid separated from the diffusion dialyzer and bipolar membrane dialyzer can be concentrated through a rectification tower or graphite evaporator to obtain the industrial-grade concentrated hydrochloric acid. The technical process can ensure that the acidic etching waste liquid can be converted into the industrial-grade high-purity concentrated hydrochloric acid and high-purity copper sulfate after adding acid once, thereby implementing complete recycling of valuable resources in the waste liquid, achieving the environmental-economical dual benefits, and having favorable application prospects.

Description

technical field [0001] The invention relates to the field of advanced treatment of etching waste liquid, in particular to a method and system for recycling waste etching liquid of PCB circuit boards. Background technique [0002] With the rapid development of electronics, computer, communication, industrial control, automobile and other industries, the scale of printed circuit board industry is getting bigger and bigger. Especially in China, the production capacity has ranked first in the world. The etching process is to use chemical reaction to corrode the copper layer of non-circuit parts. This process will produce acidic etching waste liquid containing about 150g / L copper in the production of printed circuit boards. Environmental pollution is serious, and copper resources will also be lost. Due to the uneven regional distribution of the domestic PCB industry, most of them are distributed in South China and East China, which poses a huge challenge to the environmental capa...

AI Technical Summary

Problems solved by technology

[0006] 1. Other alkaline substances need to be added when adjusting the pH value. Since the wastewater is strongly acidic, the amount of alkaline substances consumed will be relatively large, and the pH needs to be readjusted after each stage of extraction, and the volume of waste liquid will continue to increase. Increase;

[0007] 2. Low extraction capacity

[0009] Direct electrolysis of acid etching solution containing chlorine system is feasible in electrochemical theory, but in the actual operation process, it will produce toxic chlorine gas, high failure rate of equipment, low current efficiency and high operating cost.

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