Fast Metals, a startup co-founded by Sumedh Gostu, has developed a chemical process to extract valuable critical minerals from red mud, the caustic waste left over from aluminium refining. More than 3 billion tonnes of this material sit in ponds and mounds worldwide, largely untouched until now because separating its minerals from iron oxide has been too costly, meaning the technique could unlock a previously unviable resource whilst tackling a significant industrial waste problem.

The breakthrough uses another refinery waste stream, alongside additional chemicals, to process red mud through six stages, yielding saleable minerals including titanium, aluminium and rare earth elements such as scandium. Titanium dioxide fetches roughly $2.50 to $3 per kilogram, while scandium oxide can sell for around $750 per kilogram, with iron covering operating costs and the rest generating profit. Fast Metals has raised a $4.3 million pre-seed round led by New Climate Ventures, with backing from Azolla Ventures, Astor Swiss and Rio Tinto's Founders Factory accelerator, and has signed a commercial contract with mineral processor Metalox to treat one tonne of red mud and refinery waste weekly later this year.