Recycling, though very helpful for the environment, is easier said than done, especially when it comes to electronic wastes such as dead computer parts or old gadgets, which usually end up either rotting in some box in people's homes or improperly disposed of.
Current recycling methods for electronic wastes usually involve burning or using chemicals to break materials down usually result in unusable materials. However, researchers from Rice University and the Indian Institute of Science found a way to properly and safely break down electronic wastes into something that can be reused.
Current Recycling Method
As mentioned above, current recycling methods usually require electronic wastes to go through a burning or chemical process to break them down. This is not only a less safe method since it could cause dangerous fumes to diffuse in the air, it is also less practical since the heat would cause the particles to merge together until it is rendered useless and will not actually lessen the waste produced.
Postdoctoral researcher Chandra Sekhar Tiwary and his team wanted to change that.
"We propose a system that breaks all of the components — metals, oxides, and polymers — into homogenous powders and makes them easy to reuse," Tiwary says.
The Proposed Method
The research team relied on physics to devise a new recycling method for electronic wastes and tested it on old computer mice and circuit boards. Instead of making the material undergo an intense heating process, the team decided to go the other way through the process of cryo-milling.
"When you heat things, they are more likely to combine ... That's what high-temperature processing is for, and it makes mixing really easy ... But in low temperatures, they don't like to mix ... They allow everything to separate really well," Tiwary explains.
The research team set up a cryo-mill, which was filled with argon gas and contains a tool-grade steel ball, which was kept at a steady temperature of -182°F or 154 Kelvin. Then the container is shaken for up to three hours to smash the material up to somewhere between 20 and 100 nanometers wide. Once done, the crushed pieces are processed in a water bath to separate the materials into polymers, metals, and oxides.
"Then they can be reused," he said. "Nothing is wasted."
The research team's study titled "Electronic waste recycling via cryo-milling and nanoparticle beneficiation" is published in Materials Today.