Fully closed system for regenerating alkaline etching liquid and recovering copper in PCB

Abstract

The invention relates to a technology for regenerating alkaline etching waste liquid and recovering copper in a PCB. Along with the etching process, the concentration of copper ions in the etching liquid is increased until the etching liquid can not be used and becomes waste liquid. The technology adopts the following four fully closed cycles which are mutually nested: an etching liquid cycle, anextracting agent cycle, a stripping agent cycle and an ammonia gas cycle; and four main materials interact but are recycled continuously. The technical method comprises the following steps: using an extracting agent to extract partial copper from the etching waste liquid; after gravity separation, air flotation separation and fiber degreasing, controlling and adjusting the concentration of copperions to achieve the level of fresh etching liquid through the specific gravity; using a water injector to add liquid ammonia, and using pH to automatically control and adjust the ammonia concentration; and after adjusting other components, recycling for production. The extracting agent containing copper is processed by back extraction by using sulfuric acid, the extracting agent returns to the extracting section for being reused after separation, and the copper sulfate is electrolyzed into copper to be sold. The whole line recycles various resources to achieve the purposes of waste utilizationand resource recovery, and no wastes are discharged.

Description

Technical field [0001] The invention relates to a regeneration system applied to alkaline etching waste liquid in printed circuit boards, which can safely regenerate the etching waste liquid and apply it to a production line and recycle excess metal copper to achieve maximum utilization of resources and zero discharge. It is an environmentally friendly technology. Background technique [0002] Alkaline etching is an important step in the production of printed circuit boards. As the etching progresses, the concentration of copper ions in the etching solution becomes higher and higher, and the etching speed becomes slower and slower. If it is not replaced, the etching progress and quality will be seriously affected. Alkaline etching waste liquid not only contains a large amount of copper ions, but also contains other valuable chemical substances. Therefore, manufacturers will basically dispose of it by themselves or entrust qualified merchants to recycle it. [0003] At pre...

AI Technical Summary

Problems solved by technology

However, this technology will seriously reduce the speed and quality of the etching line, which is difficult for most manufacturers to accept; 3. Extraction and electrolysis to obtain copper

This method still has the following defects (1) the concentration of copper in the etching solution after extraction is difficult to be accurately controlled at 80-90g / l, which has an impact on the regeneration and reuse of the etching solution; (2) it is difficult to avoid a part of the extraction agent from entering the etching solution , affecting the effect of etching, the time is slightly longer and even destroys the etching solution, resulting in the etching solution must be completely replaced; (3) part of the material cannot be reused, and the effect of a complete closed circuit cannot be achieved; (4) the volume of the etching solution increases after adding ammonia water The more, so that the production line is difficult to fully accommodate, part of the etching solution must be discarded, and high-concentration sewage is produced; (5) The stripping time is long and the volume is large

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