You may not have heard of tantalum, but chances are you’re holding some right now. It’s an essential component in our cell phones and laptops, and currently, there’s no effective substitute. Even if you plan to recycle your devices after they die, the tantalum inside is likely to end up in a landfill or shipped overseas, being lost forever.

As a researcher focused on critical materials recovery, I’ve spent years digging through electronic waste, not seeing it as garbage, but as an urban mine filled with valuable materials like tantalum.

Researchers at the University of Tartu Institute of Computer Science introduce a novel approach to reducing electronic waste and advancing sustainable data processing: turning old smartphones into tiny data centers.

Each year, more than 1.2 billion smartphones are produced globally. The production of electronic devices is not only energy-intensive but also consumes valuable natural resources. Additionally, the manufacturing and delivery processes release a significant amount of CO₂ into the atmosphere. Meanwhile, devices are aging faster than ever—users replace their still-functional phones on average every 2 to 3 years. At best, old devices are recycled; at worst, they end up in landfills.

Although the most sustainable solution would be to change consumer behavior and consider more carefully whether every new model truly requires replacing the old one, this is easier said than done. Rapid technological development quickly renders older devices obsolete. Therefore, alternative solutions are needed—such as extending the lifespan of devices by giving them an entirely new purpose.