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Coal fly ash can supply US demand for rare earths for decades.

It's time to make resource recovery a reality.

The need for rare earth elements

Rare earth elements (REEs) play invaluable roles in a variety of technologies, ranging from electric cars, batteries, optical sensors, LED screens, satellites, permanent magnets, petroleum refining, and more. They play a tremendous part in our path to a low carbon, green tech future. Currently, there are no substitutes for REEs.


Currently, China dominates global production and processing of rare earth elements; this supply chain sensitivity led both the United States and the European Union to designate REEs as "critical minerals." More recently, President Joe Biden addressed this in an executive order 14017 (E.O.), America’s Supply Chains. Sourcing these rare earths domestically is strategically important for the United States, to ensure we can lead the world in climate and energy technology.

The green revolution is impossible without rare earth elements- but mining leads to a host of environmental problems. The answer lies is resource recovery.

Resource recovery

Resource recovery is a key element in a circular economy, and is defined as using wastes as input materials for new valuable products.

Here at Rivalia Chemical Co., we are focused on recovering rare earth elements from concentrated wastes: coal combustion residuals like coal fly ash, abandoned mine drainage sludges, tailings, and more.

Coal fly ash

Coal fly ash is produced when coal is burned for electrical power generation. The US alone produces about 130 million metric tons each year, and more than 70 million tons of CFA ends up in storage ponds (representing approximately 30 thousand tons of REEs, worth nearly USD $200 million). Even as coal combustion declines, decades’ worth of residuals (billions of tons), remain as untapped resources.

Furthermore, ash storage ponds present their own hazards to human and environmental health. Recent catastrophic spills like the Kingston Fossil Plant coal fly ash spill in 2008 have made coal ash ponds a liability for utility companies and have also spurred new regulations establishing comprehensive requirements for the safe disposal of coal ash. As the environmental and economic costs of storage increase, there is an increasing push to recycle coal fly ash.

Recovering valuable rare earth elements from coal fly ash may be a solution to both produce REEs and clean up ash ponds.

Our method

Existing methods to extract rare earth elements from solids are chemical- and energy-intensive, and their separation efficiency is low, meaning that even further processes are required to separate each of the elements from each other. Founder and CEO Dr. Laura Stoy, PhD, designed and optimized a more efficient and environmentally sustainable separation process.

This novel process has a few significant advantages. Most importantly, extraction is combined with separation from bulk elements the coal ash. This eliminates the need for total solid digestion, and streamlines downstream processing, both of which are chemical- and energy-intensive. The key reagent, an ionic liquid, can be recycled and used multiple times without loss in performance. Finally, the process involves mild operational conditions, much lower chemical consumption, and less waste generation.

Dr. Stoy has several first-author publications in high impact journals, including Environmental Science and Technology here and here, and ACS Sustainable Chemistry & Engineering here.

Technology status

This technology is currently patent-pending. Please contact us to learn more.

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