The growing demand for rare earth elements, driven by their crucial role in clean energy technologies, has raised concerns about the vulnerability of rare earth supply chains in the West, as China currently controls over 90% of the market. This concern has been heightened by China's threat to impose an export ban on rare earth elements in response to the US' recent decision to restrict exports of high-end semiconductors to Beijing. As traditional rare earth ore deposits become depleted due to imbalanced distribution and surging demand, the need for alternative and non-traditional sources of these essential metals has increased.
Researchers from the Clean Coal Technology research group at the University of Witwatersrand have discovered that coal may be a viable source of rare earth elements. Their study, titled "Rare earth elements from coal and coal discard – A review," has been published in the journal Minerals Engineering. As Western governments focus on securing domestic supply chains of rare earths, this breakthrough could provide a much-needed alternative to China's supply.
For several reasons, coal and coal byproducts have been proposed as promising sources of rare earth elements. They are abundant, enhanced with trace metals, and have already been mined, milled, and partially prepared, making them more accessible and widespread than many mineral deposits. This accessibility, combined with the fact that coal deposits require less expensive extraction methods compared to other mineral ores, makes them an attractive option for sourcing rare earth elements.
The research team used coal samples to determine that the total rare earth content in discard and standard products from coal mines exceeded 225 parts per million (ppm), which is above the minimum grade of 130ppm required for extracting rare earths in coal. Furthermore, it was discovered that light rare earths were more prevalent in high mineral content discard coal samples, while heavy rare earths were more concentrated in run-of-mine samples.
The potential to extract rare earth elements from coal and coal byproducts presents a significant opportunity to reduce dependency on China's supply of these critical metals. Reprocessing coal and its byproducts as raw materials for clean energy technologies would promote a more secure supply chain and contribute to the global energy transition. This new avenue for rare earth element sourcing could be a game-changer for countries worldwide, as they work to meet the rising demand for clean energy solutions and reduce their reliance on a single dominant supplier.