A research project led by the Critical Materials Institute (CMI), a U.S. Department of Energy Innovation Hub, has identified agents for the separation of rare earth metals that are potentially much less costly and better performing than those currently used.

Rare earth metals are in increasingly high demand for their use in consumer electronics and clean energy technologies. While these materials are not actually rare, they are difficult and costly to refine, usually through solvent-extraction processes that rely on ligands—molecules that act to bind with and separate the metals.

Rare earth metals are in high demand for their use in a wide range of consumer electronics. Image credit: Pixabay.Through the use of computer-aided molecular design, a collaboration of researchers from the Supramolecular Design Institute, Oak Ridge National Laboratory (ORNL), Ames Laboratory and Idaho National Laboratory have identified several new low-cost, highly effective ligands.

The researchers used a program called Host Designer, a molecule-building software program that is capable of exploring millions of possibilities very quickly by broadly categorizing them according to their molecular architecture.

“Think of a box of Tinkertoys,” says Benjamin Hay, CEO of the Supramolecular Design Institute. “If we were asked to build every possible structure out of those pieces, it would take a long time, maybe years. But our computer code has a database of molecular links that are like the chunks of those Tinkertoys and can build those 3D structures in every conceivable way possible. It can produce a million structures a minute and find the ones with the shapes and properties we’re looking for.”

Once millions of potential molecules were reduced to a more manageable number of about 3,000, successively more complex computational analyses were used to narrow the number of potential ligands to a handful.

Some of those have been created at ORNL, and they will be tested experimentally in realistic processing conditions by a team at Idaho National Laboratory.