Ionic Liquids as Advanced Solvents for the Extraction of Rare Earth Elements from Coal Products

The rare earth elements are commodities of great value that are necessary for many applications of modern technology, including national security (e-g-, missile defense), consumer products (e-g-, smartphones), and renewable energy (e-g-, wind turbines)- It would not be an overstatement to suggest that the United States economy and national security are now dependent on a stable supply of rare earth elements- Nevertheless, despite an increasing demand, rare earth metals are not currently being mined in the United States, due in part to the cost and negative environmental impacts of mining operations- As such, rare earths are imported almost exclusively by China, who controls an estimated 85-97% of the rare earth market, allowing not only the ability to set the price, but also to limit or restrict access to this precious commodity- Alternative rare earth sources are being investigated to alleviate the cost and environmental impact associated with mining in order to establish a reliable source of rare earths in the United States- Coal and coal by-products such as fly ash are known to contain rare earths, with an estimated 6 million MTs of rare earths in the western state coal basins- Proposed herein is a method for extracting rare earths directly from coal or coal by-products using inexpensive, nonvolatile ionic liquids designed for the direct dissolution of coal at low temperatures (<100 °C)- Once solubilized, the coal will be passed through a series of rare earth-specific biosorbents, and recovered utilizing electrodeposition-