The drive for a sustainable future has turned coal ash, a byproduct of coal-fired power plants long seen as an environmental liability, into a surprising potential source of rare earth elements (REEs). These critical materials are vital for clean energy technologies, and coal ash may offer a pathway to securing a domestic supply.
Researchers at the University of Regina have made significant strides in understanding the potential of Canadian coal ash as a source of REEs. Their findings, published in Environmental Science and Technology, reveal that the concentration of REEs in Canadian coal ash is comparable to that found in other parts of the world.
Using advanced X-ray technology at the Canadian Light Source, Bishop's team discovered that yttrium, a valuable rare earth element, is concentrated in specific minerals within the ash particles. This discovery could guide the development of efficient extraction methods, allowing companies to adapt existing ore processing techniques for coal ash.
The extraction of REEs from coal ash presents a dual advantage for businesses and the environment by addressing the growing demand for these elements, which are critical for technologies like electric vehicles and renewable energy systems. It also offers a solution to the environmental challenges posed by coal ash storage.
While some coal ash is used in concrete production, the majority is stored in landfills or tailings ponds near power plants. By repurposing this waste material, companies can simultaneously reduce their environmental footprint and contribute to the circular economy. The homogeneous distribution of REEs in coal ash also simplifies the extraction process compared to traditional mining operations.
The concentration of REEs in coal ash is not particularly high, but the sheer abundance of it makes it a promising short-to-medium-term source. Developing extraction processes for coal ash could be significantly faster than opening new mines, which often face lengthy delays between exploration and production.
As the world struggles to meet ambitious clean energy goals, innovative solutions like REE extraction from coal ash could play a crucial role in bridging the supply gap and accelerating the transition to sustainable technologies.
