A typical recycling process converts large quantities of items made of a single material into more of the same. However, this approach isn’t feasible for e-waste, because they contain small amounts of many different materials that cannot be readily separated. Researchers have recently reported a selective, small-scale microrecycling strategy, which they use to convert old printed circuit boards and monitor components into a new type of strong metal coating. The study has been published in ACS Omega.
E-waste contains potentially valuable substances that can be used to modify the performance of other materials or to manufacture new, valuable materials. Previous researches have shown that carefully calibrated high temperature-based processing can selectively break and reform chemical bonds in waste to form new, environmentally friendly materials. Based on the properties of copper and silica compounds, researchers suspected that, after extracting them from e-waste, they could combine them to create a durable new hybrid material ideal for protecting metal surfaces.
In a bid to do so, the researcher’s first heated glass and plastic powder from old computer monitors to 2,732 °F, generating silicon carbide nanowires. They then combined the nanowires with ground-up circuit boards, put the mix on a steel substrate then heated it up again. This time the thermal transformation temperature selected was 1,832 °F, melting the copper to form a silicon-carbide enriched hybrid layer atop the steel. Microscope images revealed that, when struck with a nanoscale indenter, the hybrid layer remained firmly affixed to the steel, without cracking or chipping. It also increased the steel’s hardness by 125%. The team says that this microrecycling has the potential to transform e-waste into advanced new surface coatings without the use of expensive raw materials.
