N.A. Thiele
Oak Ridge National Laboratory,
United States
Keywords: leaching, lixiviants, rare earths
Summary:
Leaching is the first step in chemically extracting rare earth elements (REEs) from mineral sources. As such, it presents the first opportunity to begin the arduous task of intra-element RE separation. This opportunity is squandered with conventional leaching practices because they rely on the use of strong mineral acid and base lixiviants. These lixiviants possess no REE selectivity and therefore afford only bulk dissolution. The overarching goal of our project is to develop lixiviants capable of targeted leaching of REEs from mineral feedstocks based on their ionic radii. In this presentation, we describe the synthesis and characterization of several novel lixiviants that possess the unique preference for binding large over small REEs. Additionally, we share our results from leaching studies with mixed RE hydroxide and oxide samples derived from industry sources. Our research highlights how fundamental coordination chemistry principles can be applied to industrial processes such as hydrometallurgical leaching to make REE recovery more efficient and economical.