How to extract and recycle PCB circuit board precious metals?

With the industrialization and scale of PCB processing and the wide application of electronic products, more and more electronic wastes are generated and manufactured in the production and living activities of human society.

Waste PCBs contain heavy metals such as lead, mercury, and hexavalent chromium. If they are discarded at will, PCBs also contain toxic chemicals such as polybrominated biphenyls (PBB) and polybrominated diphenyl ethers (PBDE) as flame retardant components. Not only will it pollute the environmental soil and water resources, potentially endanger human health, but also cause wasted resources, which are difficult to recycle. There are nearly 20 kinds of non-ferrous metals and rare metals on scrap PCBs, which have high economic value for recycling.

Therefore, it is particularly important to properly dispose of waste PCB circuit boards.

At present, the most common method is to disassemble and recycle waste circuit boards by mechanical and physical crushing and sorting, and then use related technical equipment to extract precious metals.

Physical crushing and sorting

According to the different physical properties of PCB, physical and mechanical means are used for recycling.

Crushing: Mechanically crushing PCBs to disintegrate and separate metals and organic matter to improve sorting efficiency. When the crushed particles reach 0.6mm, the metal can basically achieve 100% dissociation, but the selection of the crushing method and the number of stages depends on the subsequent process.

Sorting: According to the differences in physical properties of the crushed materials such as density, particle size, electrical conductivity, magnetic permeability and surface characteristics, wind shaker technology, flotation separation technology, cyclone separation technology, floating-sink separation and eddy current separation technology can be used Wait, sort.

Hydrometallurgical precious metal extraction

Hydrometallurgy technology, placing PCBs in acid solutions such as nitric acid, sulfuric acid, and aqua regia, to remove metals from electronic waste and then recycle them. It is currently the most widely used method for dealing with electronic waste. Compared with pyrometallurgy, hydrometallurgy has the advantages of less waste gas emission, easy treatment of residues after metal extraction, significant economic benefits, and simple process flow.

E-waste has complex and diverse characteristics, and it is difficult to recycle it completely with a single recycling technology. The e-waste treatment technology needs to be continuously optimized to maximize resource recovery, scientific and industrialize the treatment technology. In short, the processing and recycling of waste PCBs can not only protect the environment and prevent pollution, but also facilitate the recycling of resources and promote sustainable social and economic development. As a professional e-waste recycling solution provider, SUNY GROUP has rich experience and complete technical equipment. If you want to know more, please feel free to leave a message with us or contact us for consultation.