PCB recycling steps
Any item will be damaged due to continued use, especially electronic products.
However, damaged items are not completely waste and can also be recycled.
The same is true for PCBs. Moreover, with the advancement of science and technology, the number of electronic products has increased dramatically, which has shortened their service life. Many products are discarded without being damaged, resulting in serious waste.
Products in the electronics industry are updated very quickly, and the amount of discarded PCBs generated is also staggering.
Every year, there are more than 50,000 tons of discarded PCBs in the UK, and up to 100,000 tons in Taiwan. Recycling is the principle of saving resources and green production. Moreover, some substances in electronic products can be harmful to the environment, so recycling is inevitable.
The metals contained in PCB include common metals: aluminum, copper, iron, nickel, lead, tin and zinc; precious metals: gold, palladium, platinum, silver, etc.; rare metals rhodium, selenium, etc. PCB also contains a large number of polymers derived directly or indirectly from petroleum products, which have high calorific value. They can be used to generate energy and produce related chemical products. Many of the ingredients are toxic and harmful. If discarded, it will cause great pollution.
PCB templates are composed of a variety of elements.
Even if they cannot be used normally, the elements can still be recycled.
Aluminum PCB
So, how to recycle it? Let’s introduce the steps:
1. Stripping paint
The PCB surface is coated with protective metal, and the first step in recycling is to remove the paint.
Paint strippers include organic paint strippers and alkaline paint strippers.
Organic paint strippers are highly toxic and harmful to the human body and the environment.
They can be dissolved by heating with sodium hydroxide, corrosion inhibitors, etc.
2. Broken
After the PCB is dismantled, it will be crushed.
The crushing methods include impact crushing, extrusion crushing and shear crushing.
The more commonly used is ultra-low temperature freezing and crushing technology,
which can cool down tough materials, embrittle them and then crush them, completely dissociating metals and non-metals.
3. Sorting
The crushed materials need to be sorted according to the density, particle size,
magnetic conductivity, electrical conductivity and other characteristics of each component.
There are usually dry and wet sorting methods.
Dry separation includes dry screening, magnetic separation,
electrostatic, density and eddy current separation, etc.
Wet separation includes hydrocyclone classification, flotation, hydraulic shaker, etc.
The sorted materials can be reused.
