Terbium (4600 $/kg)* and Dysprosium (2200 $/kg)* are key components of permanent magnets used in electric vehicles, wind turbines, and defense systems. Intra-lanthanide separation is one of the most challenging problems in chemical engineering because the valence shell electronic configuration and preferred oxidation states of the lanthanides are nearly identical. Current separation strategies, such as solvent extraction, rely on subtle, monotonic changes in thermodynamic properties across the series. As a result, they require hundreds of stages, which makes them energy-intensive and inefficient. In this thrust, we will develop novel electrochemical strategies to separate these critical rare earth elements. We will focus on rare earth concentrates derived from secondary domestic resources, such as coal by-products (refuse, ash, acid mine drainage, and tailings) and end-of-life permanent magnets that cannot be reused or recycled. Our initial work will target the selective separation of Tb from these concentrates, and we will later extend these approaches to Dy, Nd, and other lanthanides.