The ceramic material Powell showed me—which is made of zirconium oxide—replaces the carbon electrode and eliminates those emissions. Researchers have been trying to replace carbon for many years, but the molten salts have corroded the alternatives. The key advance for Infinium was developing alternative molten salts that don’t react with the zirconium oxide, so that it can last long enough to be practical.

via Startup Has a New Way to Make Rare Earths and Other Metals | MIT Technology Review.

Finding an alternative to carbon has long been the “dream” of the metals industry, says Donald Sadoway, a professor of materials science at MIT who is not involved with the company. “I believe [Infinium’s] technology is sound. It’s real,” he says. Whether the company succeeds “is all about the economics,” he says. “No one cares about the flow chart for the process. You care about the prices. If it produces a good metal at a lower cost, people will be interested.”