Sustainable method for recovering neodymium from electronic waste

Kate Myers

A NEW method has been developed to remove neodymium from electronic waste using cellulose, which could lead to more effective recycling.

Neodymium (Nd) is needed for clean technologies such as electric vehicles and wind turbines, and demand for it has increased by around 400% in the last 20 years. However, mining for this rare earth element has a harmful impact on the environment, necessitating more recycling of Nd from electronic waste. Its recovery comes with its own set of challenges. The main commercial recycling method uses solvent extraction, but this has low selectivity, is expensive, and is unsustainable through its use of toxic organic solvents.

A new method has been developed by researchers at The Pennsylvania State University, US, where new nanotechnology is used to recover Nd using plant cellulose. Cellulose is inexpensive, renewable, and abundant. Previous work has been done on cellulose-based adsorbents but these have been inefficient.

The Penn State team developed a new biotechnology named anionic hairy nanocellulose (AHNC), where “hairy” refers to cellulose chains attached to the ends of the nanoparticles. The hairy layers of the nanoparticles are negatively charged so that they attract the positively-charged Nd ions. This separates the Nd from other ions such as iron, calcium, and sodium in aqueous media, and gathers enough Nd particles so that it can be effectively recycled.

Amir Sheikhi, Assistant Professor of Chemical Engineering and Biomedical Engineering at Penn State, said: “The process is effective in its removal capacity, selectivity and in its speed. It can separate neodymium in seconds by selectively removing the element from some of the tested impurities.”

The process could also be used to extract Nd from industrial wastewater, mining tailings, and permanent magnets that are no longer in use.

“This contribution to rare earth recycling will have a strategic and economically-viable impact on several industries,” said Sheikhi. “The more neodymium we recycle, the more we can manufacture electric and hybrid vehicles and wind turbines, leading to less strain on the environment.”

Sheikhi added that the team are currently exploring different routes to developing continuous or semi-batch adsorption systems, which will pave the way for scaling up the process.

Chemical Engineering Journal https://doi.org/hc4h