Robert F. ServicePractical and glamorous, aluminium is prized for making products from kitchen foil and beverage cans to Tesla Roadsters and aircraft.
But the silvery metal—abundant, cheap, lightweight, and corrosion resistant—has a dark side: red mud. This brownish red slurry, a caustic mishmash of metal- and silicon-rich oxides, often with a dash of radioactive and rare earth elements, is what’s left after aluminum is extracted from ore.
And it is piling up. Globally, some 3 billion tons of red mud are now stored in massive waste ponds or dried mounds, making it one of the most abundant industrial wastes on the planet.