Sustainable production of rare earth metals for permanent magnets through ultrasound-assisted organic acid leaching

This project aims to produce critical materials from domestic resources in the Pacific Northwest region. Our team proposes a continuous ultrasound-assisted organic acid leaching process for producing rare earth metals (REMs) for permanent magnets, the core component of many clean energy technologies, such as wind energy. To meet net-zero goals, for wind energy alone, REM production needs to increase by 7X by 2050 (Dominikowski, 2024). Increasing the domestic supply of critical materials is crucial to achieving the Biden Administration’s goals for net-zero emissions, economy-wide, by 2050.

Ultrasound-assisted organic acid leaching has the potential to be a breakthrough technology enabling sustainable and cost-effective domestic production of critical minerals including REMs. Conventional solvent extraction processes for REMs lack in both sustainability and cost efficiency (Ichihara and Harding, 1995). Every ton of REM from the conventional process produces 2,000 tons of hazardous waste (Kaiman, 2014) and requires significant energy for the production of solvents (Zapp 2022). The proposed ultrasound-assisted organic acid leaching process coupled with molten salt electrolysis employs a single harmless solvent and creates no hazardous waste, while reducing energy consumption by ~10X during leaching (Brown et al., 2024) and by 35-45% during electrolysis by using a molten halide salt (Fatunde, 2024). The primary research objectives are to increase the process efficiency of ultrasound-assisted organic acid leaching and develop REM-based magnets from domestic minerals. At 10,000 tons per year of monazite processed, this process would produce enough REMs annually to install ~2.4 GW of wind energy capacity, enough to power over 820,000 homes (USGS 2024).