Can you Recycle a PCB?

If you think about it, almost all electronic devices found out there have their components sitting in a nice looking Printed Circuit Board or PCB. No one sells a device with their electronics stuck on a breadboard and hold by electrical tape (or I hope not).

Since electronic devices are booming, PCBs are everywhere. Making sure their materials can be collected and reused instead of just throwing them into a landfill would potentially be a smart and environmentally sensible move if performed properly.

In this article, we will discuss the issue of PCB recycling, if it’s possible at all, how it is done and what can we do as electronics design engineers to create more recyclable PCBs. Note that with PCB we mean the PCB without any components.

Can a PCB be recycled?

Yes and no

Before jumping into a final conclusion let’s first see what a PCB is made of. A PCB is basically a layered sandwich of copper and FR-4. FR-4 is a fibreglass with an epoxy resin that has the purpose of bonding the fibre together and as an adhesive, it is also flame resistant. Apart from that, you can also find tin and small traces of gold and silver.

Although this article is concerned with PCB recyclability, I will encourage you to watch the following video from EVVBlog about how a PCB is manufactured. By watching this video you will understand better about the different materials used and how they come all together:

Back to our initial question, can PCB’s be recycled? If we are strict with the definition of recycling, then, only partially. When recovering the main materials from a PCB (copper and FR-4), only the copper can come out with enough purity to be used again as a conductive material, while the fibreglass will undoubtedly degrade in quality. So, a more correct definition will be that a PCB can be both recycled and downcycled. The copper can be used again as an electrical conductor while the fibreglass in low-tech applications such as in building insulation.

How are PCBs recycled

PCBs can be recycled in three different ways, all of them with their pros and cons.

Thermal Recovering

The thermal recovering process heats up the PCB at a very high temperature with the idea of only recovering the metals present on the board (the FR-4 gets incinerated). This method can be easily implemented but produces deleterious gases such as dioxin and lead fume.

Chemical Recovering

The thermal recovering process involves putting the PCB in a bed of acid. The output recovers the metals but carbonizes (destroys) the FR-4 component. It also produces a high amount of wastewater which must be treated before sending it back to the environment.

Physical Recovering

Physical recovering is achieved by shredding and smashing the PCBs and then separating the metals from the non-metals. This process has no direct environmental impact but it is hazardous for the operators as the machinery is extremely loud, dust particles with heavy metals and glass fibre float in the factory which can cause respiratory diseases and an irritant odour is present because of the rise of temperature when the PCB is smashed and shred. In the following video from Suny Group, the physical recovering process can be appreciated:

What can you do as an electronics engineer to make your PCB more recyclable?

As an electronics design engineer, there is not much if anything at all that we can do to improve the recyclability of a PCB.

There seems that we can’t do anything to make the recycling process easier. If anything, use SMD components instead of THT as this can be separated from the board easier and use a copper thickness of <1 Oz (which is the standard for low power).

Fortunately, most of the embodied energy from the circuit comes from the components and not the PCB, so it shouldn’t be much of a worry.

As we have seen in this article, PCBs can and are currently being recycled, or more accurately, PCBs are processed and broken down to recover metals and fibres that can be re-purposed for another low-tech product.

Chemical recovering is the less environmentally friendly option as it requires a good effort in water treatment while thermal and physical recovering are hazardous for the operatives. Also, they are all very energy demanding processes.

For a recycling scheme to make sense in terms of sustainability, it would probably have to be the physical recovering method done with the appropriate precautions and in a facility that it is powered by renewable energies, otherwise, the burn of fossil fuels used to power the facility will probably have a bigger impact than the one that can be “recovered” from using recycled materials.

Have you recycled PCBs before? Can you think in a better way to do it? Share your thoughts in the comments section below!

References

Dong Xiang, Peng Mou, Jinsong Wang, Guanghong Duan, Hong C. Zhang “Printed circuit boards recycling process and its environmental impact assessment”
Posted in: Sustainable Design

2 comments

  1. Interesting read! Perhaps the best we can do is to design boards as small and thin as possible, to minimize future waste. By the way I’ve seen an interesting method of upcycling PCBs recently, look up “therecomputing” – an artist couple from Slovakia who make bits and pieces of old PCBs into very good looking “jewellery”.

    1. Certainly! as a general rule of thumb, by using less material with less processing, the embodied energy of a component is reduced. That’s a very sustainable way to downcycle PCBs, they don’t go to the landfill and no processing is needed for their new purpose.

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