The Idaho National Laboratory is part of the DOE.
In the scientific world, a process can have many different applications. Idaho National Laboratory researchers have adapted a water treatment technology toselectively separate rare earth elements and transition metals. The rare earth element recovery process is affected by this chemical process.
At low concentrations in nature, rare earth metals can be difficult to separate from one another, which is why they're called rare earth metals. They are used in electric car motors, computer hard drives, and wind turbine generators. Transition metals are excellent conductors of heat and electricity, often with high melting points and unique structural properties, making them essential for the production of common metals like steel and copper.
Most of the components are thrown away. One of the first commercial refrigerants was dimethyl ether, which INL's new method to extract these precious metals involves. It drives fractional crystallization, which splits chemical substances based on their solubility, to separate rare earth elements and transition metals.
The lead for the project said that the process began with a magnet that was no longer useful. The liquid used to extract metal from the material is called lixiviants. We can apply a treatment process after the desired metals are removed.
Traditional methods use much more energy and pressure than the dimethyl ether-driven process. It is possible to carry out fractional crystallization at ambient temperatures. The pressure in a can of soda is less than 3 atmospheres. Money can be saved by the lower energy and pressure needs.
Competing technologies use added chemical "reagents" to drive precipitation and other separations, which can lead to additional waste products. This isn't the case with fractional crystallization using dimethyl ether.
dimethyl ether was selected for its ease of recovery by the project's principal investigator. The team can recover the solvent if they drop the pressure at the end of the experiment.
Other advantages include the process. The fractional crystallization process eliminates all the challenges of adjusting to the temperature. The temperature needs to be adjusted by 10 degrees for the process to work.
The team worked closely with some of the rare earth metal recovery processes already in place. The E-RECOV effort uses a cell to recover metals from electronics that have been thrown away. The environmental justice implications of reducing energy intensity and waste are significant. In the past decades, primary extraction, like mining and enhancing the economic value of the product, has been shifted to underdeveloped nations. The public's opposition to "dirty" mining processes in their backyard has led to much of this offshoring. Without exposing underserved communities to hazardous conditions, creating a cleaner method will facilitate critical materials recovery.
Wilson and his research team are working on a project to address synthetic gypsum production related waste. Synthetic gypsum is the source of 30% of the dry wall in the US. They are isolating the waste from the manufacturing process. The treatment has the potential to create more products from the original problem.
The rare earth element and transition metal recovery work would not have been possible without INL collaborating with the Critical Materials Institute at Ames National Laboratory. This has made it possible for us to conduct research at the lab scale.
More information: Caleb Stetson et al, Solvent-driven fractional crystallization for atom-efficient separation of metal salts from permanent magnet leachates, Nature Communications (2022). DOI: 10.1038/s41467-022-31499-7 Journal information: Nature Communications Provided by DOE/Idaho National Laboratory
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