A kind of method for recycling and recycling photocatalytic pcb acid etching solution

Abstract

The invention discloses a method for recycling a PCB (printed circuit board) acidic etching solution under photocatalytic actions. The method comprises the following steps: an etching waste solution overflowing from an etching cylinder on the production line flows into a waste solution collection tank; the etching waste solution flows into an oxidation reaction tank from the waste solution collection tank, and reacts by adding a photocatalyst under lighting conditions; the oxidated waste solution flows into a precipitation reaction kettle provided with a cation exchange membrane, and meanwhile, a precipitant is added to form a precipitate-containing mixed solution; the mixed solution is subjected to solid-liquid separation; part of the filter residue is refined and purified, and then is sold in the form of cupric oxalate, and the rest is decomposed into activated copper oxide for sale; the filtrate flows into a dewatering system after hydrochloric acid is supplemented, thereby removing excessive moisture; and finally, the filtrate flows into a storage tank to become the recycled solution for etching. The copper is reutilized in the technical process: the copper is extracted properly by balanced operation, and part of copper is recycled. Only a certain amount of clean water is discharged, and no waste solution is discharged, thereby implementing closed cycle production. The process is simple in equipment and convenient to control, has wide popularization prospects, and has obvious economic value and social and environmental benefits.

Description

technical field [0001] The invention relates to the field of recycling and utilization of circuit board etching waste liquid, in particular to a method for recycling and utilizing photocatalytic PCB acidic etching liquid. Background technique [0002] The printed circuit board (PCB) industry is one of the most important components in the electronics industry, and plays a pivotal role in the electronic information industry. In recent years, with the rapid development of the electronics industry, the demand for PCBs is increasing day by day. Acid etching is an important process in the manufacture of printed circuit boards (PCB). A large amount of high-copper etching waste liquid is produced during the production process. The etching waste liquid is a hazardous liquid waste and contains a large amount of polluting components such as copper and chlorine. If it is not treated strictly If it is directly discharged into the environment, it will not only cause waste and loss of reso...

AI Technical Summary

Problems solved by technology

Acidic etching waste liquid seriously pollutes the environment, affects the survival of microorganisms in water, destroys the structure of soil aggregates, and affects the growth of crops

The existing recycling technologies for acidic etching solutions have obvious defects. Due to the limitations of recycling costs, regeneration solution quality, control difficulty, process continuity, etc., as well as the lack of equipment investment capabilities of small and medium-sized enterprises, most of them use The factory of the acid etching process does not adopt the recycling process, but transfers the waste liquid to the environmental protection company for treatment

[0004] Although in accordance with the relevant regulations, the relevant departments require the centralized treatment of industrial wastewater, but the centralized treatment of PCB etching liquid wastewater inevitably has the following problems: First, the operating cost of sewage treatment is relatively high, because the wastewater comes from different production processes, Therefore, the quality of wastewater is very complex, and a single treatment process cannot solve all the problems. Therefore, to achieve standard discharge of wastewater in industrial parks that are difficult to treat, a combined process of physics-chemistry-biology is used, and chemical methods such as dosing chemicals are usually used. It will greatly increase the operating cost; second, the investment requirements for sewage treatment equipment are high. According to national requirements, manufacturers with an investment of more than 10 million in waste water treatment equipment are qualified to treat PCB waste water, and small and medium-sized enterprises are unable to complete this project. Investment; Third, the recycling rate of etching solution is low. At present, my country usually only recycles copper with relatively high value in waste liquid in the process of PCB etching solution wastewater treatment in China, while ignoring the treatment and reuse of polluting components such as chlorine, so there is no Can thoroughly achieve "full recovery as much as possible, with little or no emissions"

Some companies are small in scale and poor in equipment, but fail to meet the standard discharge of waste liquid. In this regard, governments in developed regions of the electronics industry have issued policies to strengthen management. For example, Jiangsu Province issued a document in October 2014 to improve copper recovery and waste water discharge. Standards, and it is stipulated that the PCB waste liquid treatment plant must have a certain scale, and the investment in equipment construction must be more than 10 million yuan before the factory is allowed to build

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