Rapid flash Joule heating technique unlocks efficient rare‑earth element recovery from electronic waste

(Press-News.org) 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. Their study was published in the Proceedings of the National Academy of Sciences Sept. 29, 2025.

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. The breakthrough supports U.S. efforts to boost domestic mineral supplies.

“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 vaporize 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 nonrare 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% purity and yield for REE recovery in a single step. The LCA and TEA revealed an 87% reduction in energy use, an 84% decrease in greenhouse gas emissions and a 54% reduction in operating costs compared to hydrometallurgy. 

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

Toward 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. 

This Rice intellectual property has been licensed to Flash Metals USA, a startup company in Texas’ Chambers County that will be in production mode by the first quarter of 2026 to capitalize on this process.  

Co-authors of the study include Rice’s Justin Sharp, Bing Deng, Qiming Liu, Lucas Eddy, Weiqiang Chen, Jaeho Shin, Shihui Chen, Haoxin Ye, Khalil JeBailey, Bowen Li, Tengda Si and Kai Gong.

This research was supported by the Defense Advanced Research Projects Agency, the Air Force Office of Scientific Research and the U.S. Army Corps of Engineers.

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