Toxic waste turning into goldmine for rare earth elements Scientists say

An article published by CNN features that millions of tons of coal ash, a byproduct of burning coal, are sitting in ponds and landfills across the US, posing a significant environmental risk. 

Millions of tons of coal ash, a byproduct of burning one of the world's dirtiest fossil fuels, are stored in ponds and landfills, where they risk leaching into waterways and contaminating soil. However, this toxic waste could also hold valuable rare earth elements crucial for advancing clean energy.

Researchers from the University of Texas at Austin analyzed coal ash from power plants across the United States and discovered that it could contain up to 11 million tons of rare earth elements — nearly eight times the amount held in domestic reserves — worth an estimated $8.4 billion.

This presents a major opportunity for domestic rare earth supply without the need for new mining, explained Bridget Scanlon, a study author and research professor at UT’s Jackson School of Geosciences. “This really exemplifies the ‘trash to treasure’ mantra,” she said. “We’re essentially trying to close the cycle and recover resources from waste.”

These so-called rare earth elements, which include metals like scandium, neodymium, and yttrium, are found in the Earth's core and play a vital role in clean technologies such as electric vehicles, solar panels, and wind turbines.

Although they are not actually rare in nature, these metals are challenging to extract and separate from the surrounding ore, which has led to demand surpassing supply.

As the world shifts away from fossil fuels, the demand for rare earth elements is expected to increase up to seven times current levels by 2040, according to the International Energy Agency.

However, the US supply remains limited, with the only large-scale rare earth mine being Mountain Pass in California. The country currently imports more than 95 per cent of its rare earth elements, with the majority coming from China, raising concerns over supply chain and security risks.

“We need to improve the situation,” Scanlon said. She explained that this is why there has been a focus on exploring unconventional sources of rare earths, "and one of these sources is coal and coal byproducts."

While coal ash contains lower concentrations of rare earth elements compared to underground deposits, the benefit lies in its ready availability. The US produces about 70 million tons of coal ash annually.

“There’s huge volumes of this stuff all over the country. And the upfront process of extracting… is already taken care of for us,” said Davin Bagdonas, a study co-author and research scientist at the University of Wyoming.