Coal ash could be a source of rare earth elements

Toxic waste from burning the world’s dirtiest fossil fuel has been identified as an unlikely treasure trove of the rare earth elements required to build clean energy sources.

Coal ash from US power plants could contain up to 11 million tonnes of these metals, nearly eight times the amount found in domestic reserves, according to the University of Texas at Austin.

Currently the US imports more than 95 per cent of its rare earth elements and last week China, the main producer, decided to ban exports of three of them.

In that context, scientists say extracting them from two billion tonnes of coal ash stored across the US is a no-brainer. Last April the Biden administration announced a $17 billion investment into coal waste projects.

But the outstanding issue is cost: expensive acids and bases are needed to strip out the metals. The economics of mining are simpler.