The Massachusetts company, formerly called MOxST, is expanding facilities purpose-designed for the breakthrough process, which can make dysprosium, neodymium, magnesium and other materials.

Infinium's oxide-based process, which uses inert anodes and high-purity materials to "virtually eliminate" emissions, moves away from environmentally unfriendly techniques often used offshore, where regulations are "dramatically less stringent", says chief executive Steve Derezinski.

"We clearly saw the continuing gap in onshore metals refining capability at least through the next decade," he says.

"We