Fast Metals is treating waste with more waste to extract critical minerals

Aluminum has left an indelible mark on the world — more than 3 billion tons of red mud, a waste product of the refining process, are currently stored in open-air ponds or mounds. But to Sumedh Gostu, co-founder and CEO of Fast Metals , there’s treasure in the caustic waste.

“It is a very rich resource,” he told TechCrunch. “If you attack with the right chemistry, it can be very profitable.”

Gostu thinks Fast Metals has found that chemistry, which just so happens to be partially comprised of another waste stream, also produced from alumina refineries.

The startup recently raised a $4.3 million pre-seed round led by New Climate Ventures with participation from Azolla Ventures, Astor Swiss, and Rio Tinto’s accelerator, Founders Factory.

Red mud’s vermillion hue comes largely from rusted iron, which is the most common compound in the mix. But the byproduct also contains critical minerals , including titanium, aluminum, and rare earth elements.

Despite its mineral riches, red mud has largely been ignored because it has been too expensive to separate those minerals from the iron oxide, Gostu said. “We are removing that impediment,” he said.

Gostu had designed most of the process during his doctoral studies at the Colorado School of Mines. But one piece was missing, until one day, while talking with his fellow co-founder Anthony Staley, things fell into place. “We were like, ‘oh wait, theres’s a waste stream which can make the whole process very economical, and it’s lying right there,’” Gostu said.

Fast Metals applies this waste stream, along with other chemicals, to red mud over six different steps. Different minerals fall out along the way, each of which can be sold.

“Iron pays for the opex, and the other stuff is profit,” Gostu said.

The profit potential is significant. Titanium dioxide sells for around $2.50 to $3 per kilogram, while scandium oxide sells for about $750 per kilogram .

With the fresh funding, Fast Metals plans to scale up its process. The startup has a commercial contract with Metalox, a mineral processor, to treat one ton of red mud and refinery waste per week later this year.