Rare-earth elements (REEs) have excellent electronic, optic, catalytic, and magnetic properties, making them useful for a wide range of applications, such as catalysts, phosphors and pigments, batteries, permanent magnets, and ceramics. The global REE consumption was estimated at 119,650 metric tons in the form of rare-earth oxides (REOs) in 2016 with catalysts being the largest segment, followed by permanent magnets.