Rare-earth materials efficiently extracted from electronic waste

A team of researchers, including Rice University’s James Tour and Shichen Xu, has developed an ultrafast, one-step method to recover rare earth elements (REEs) from discarded magnets using an innovative approach that offers significant environmental and economic benefits over traditional recycling methods..

Conventional rare earth recycling is energy-heavy and creates toxic waste. The research team’s method uses flash Joule heating (FJH), which rapidly raises material temperatures to thousands of degrees within milliseconds, and chlorine gas to extract REEs from magnet waste in seconds without needing water or acids.

“We’ve demonstrated that
we can recover rare earth elements from electronic waste in seconds with minimal environmental footprint,” said Tour, the T.T. and W.F. Chao Professor of Chemistry, Professor of materials science and nanoengineering and study corresponding author.

“It’s the kind of leap forward we need to secure a resilient and circular supply chain.”

Hypothesis rooted in thermodynamic selectivity
The researchers proposed that FJH combined with chlorine gas could take advantage of differences in Gibbs free energy, a measure of a material’s reactivity, and varying boiling points to selectively remove non-REE elements from magnet waste.


In the presence of chlorine gas, elements such as iron or cobalt would chlorinate and vaporise first, leaving the REE oxides behind.

The research team tested this process on neodymium iron boron and samarium cobalt magnet waste using ultrafast FJH under a chlorine atmosphere. By precisely controlling the temperatures and heating the materials within seconds, the non-REE elements were converted into volatile chlorides, which then separated from the solid REEs.

The scientists observed that the non-rare-earth elements were removed almost instantaneously, enabling the recovery of a purer rare-earth residue.

“The thermodynamic advantage made
the process both efficient and clean,” said Xu, the first author of the study and a postdoctoral associate at Rice.

“This method not only works in tiny fractions of the time compared to traditional routes, but it also avoids any use of water or acid, something that wasn’t thought possible until now.”

In addition to laboratory experiments, the researchers conducted a comprehensive life cycle assessment (LCA) and techno-economic analysis (TEA) to benchmark their process.

They achieved over 90 percent purity and yield for REE recovery in a single step. The LCA and
TEA revealed an 87 percent reduction in energy use, an 84 percent decrease in greenhouse gas emissions, and a 54 percent reduction in operating costs compared to hydrometallurgy. 

The process eliminates the need for water and acid inputs entirely, according to the study.

Towards scalable, circular rare-earth economy
The new method makes it possible to build small or large, easy-to-use recycling units that can be placed close to where electronic waste is collected.

These local systems can process used magnets quickly and cleanly, cutting down on shipping costs and helping the environment.

“The results show that this is more than an academic exercise; it’s a viable industrial pathway,” Tour said.