PCBs

Have you ever wondered what happens to your electronic devices when you replace them? Phil Simmonds, Group Managing Director of electronic manufacturing services provider EC Electronics, offers a rundown.

In 2018, the issue of single-use plastics came to the forefront and captured the world’s attention. But what about the arguably even more concerning challenge of tackling electronic waste (or ‘e-waste’)?

Recycling e-waste involves a combination of processes, including manual and mechanical dismantling, size reduction, sending hazardous waste for final disposal, and processing metal components. However, given that a single electronic product can contain more than 1,000 different substances, this task is no mean feat.

As electronic products such as laptops and smartphones have become increasingly pervasive in our society, the challenge of global e-waste management has grown considerably. The world currently produces up to 50 million tons of e-waste a year (and only 20% of this is formally recycled). If current trends continue, that number is expected to reach 120 million tons per year by 2050.

A complicated process
Printed circuit boards (PCBs) are integral to any electronic product. But recycling PCBs in an efficient and environmentally friendly way can be an enormous challenge.

PCBs are typically composed of 30% metallic and 70% non-metallic materials. They contain organic matter (such as resin and brominated flame retardants), chemical residuals and heavy metal elements that can be seriously damaging to the environment and human health. However, they also contain high-grade precious metals such as palladium, silver, copper and gold. (As much as 7% of the world’s gold may currently be contained in e-waste!) Recycling waste PCBs effectively is, therefore, a complicated process.

With traditional mechanical recycling methods, waste PCBs are dismantled and crushed and then physically separated using magnetic or high-voltage electrostatic methods. This approach is widely used in many countries because it is relatively low cost and environmentally friendly. However, although the metallic components are easy to recover, it is not so easy to separate the heavy metal elements from the high-grade precious metals.

In comparison, thermal or chemical recycling technologies can obtain purified metals, offering much higher efficiency and economic return. But these methods often require high processing temperatures or high pressure, which can lead to pollution through hazardous fumes.

To make recycling economical, PCBs also have to be consolidated into bulk amounts. As a result, many will cut corners where possible — and PCBs will, ultimately, end up in landfill.

Positive steps forward
Although not given as much media coverage as single-use plastics, behind the scenes, the electronics manufacturing industry has been working hard to manage and reduce e-waste over the years. And things are looking up.

According to a recent report, the global e-scrap and PCB e-scrap market is growing at a CAGR (compound annual growth rate) of 7.6% during the forecast period (2019–2027). This growth is largely being driven by the increased numbers of regulations mandating proper e-waste management.

In Europe, the RoHS (Reduction of Hazardous Substances) Directive aims to eliminate toxic substances in electrical and electronic equipment (EEE). The legislation, which came into force in 2003, requires heavy metals such as lead, mercury, cadmium and flame retardants like polybrominated biphenyls (PBB) or polybrominated diphenyl ethers (PBDE) to be substituted by safer alternatives.

In 2003, the first WEEE (Waste Electrical and Electronic Equipment) Directive was also introduced, providing regulations for recycling all electronic waste. Under WEEE, any company that manufactures, distributes or sells electrical and electronic equipment must contribute to ensuring it is disposed of and treated correctly. However, individuals do not have a legal obligation to comply with this legislation.

The WEEE and RoHS directives were revised in 2008 and 2011, respectively, introducing stricter measures to increase the amount of waste EEE that is appropriately treated and reduce the volume that goes to disposal.

The world’s resources are not infinite, and precious metals such as gold and silver will run out eventually. So, recycling these materials will play a massive part in sustaining electronics manufacturing in the future.