There’s a ton of e-waste in the world. In fact, a report from the United Nations stated that in 2014, with 42 megatons of e-waste produced worldwide, only one-sixth was recycled or reused. Recycling is tricky – burning or using chemicals takes a lot of energy and still leaves waste and toxic components like mercury and and chromium into the environment. Plus, recycling wastes a gigantic amount of valuable metals like iron, gold, silver, copper and aluminum.
Now, researchers at Rice University and the Indian Institute of Science have a new way to tackle the e-waste issue: freeze it, grind it into “nanodust” and then sort it out.
Chandra Sekhar Tiwary, lead author of the study said “if you heat things, they are more likely to combine, but in low temperatures they don’t like to mix.We propose a system that breaks all of the components – metals, oxides and polymers – into homogenous powders and makes them easy to reuse.”
The team uses liquid nitrogen to cool the waste to -182 degrees fahrenheit. When the temperatures are that low, the materials are easy to smash up and separate in what they call a “cryo-mill” which is made up of a container of argon gas and a steel ball.
To test their technique, the team threw the printed circuit boards of computer mice into the cryo-mill. With the liquid nitrogen keeping the components at a constant, ultra-low temperature, the device is shaken so the steel ball grinds the e-waste down over about three hours.
The end result is a powder with particles measuring between 20 and 100 nm each. That nanodust is then bathed in water to separate the polymer, metal and oxide particles from each other, allowing them to be reused with virtually no waste.
This scientific breakthrough provides relief in a world where e-waste is becoming one of our most pressing environmental concerns.