A.W.S. Ooi, H.B. Vibbert, A.-H.A. Park
Columbia University,
United States
Keywords: sustainable mining, unconventional resources, aldoxime, cobalt, nickel, hybride materials
Summary:
Energy-relevant metals are crucial for building renewable energy infrastructures. However, current industrial mining practices are unsustainable and call for developing new technologies to explore alternative feedstocks and greener hydrometallurgical extraction processes. Unconventional resources such as waste-to-energy ashes and e-waste are particularly important feedstocks because they contain many of these critical elements. However, they present different challenges in the heterogeneity of their compositions and thus require the need to understand them from a more fundamental point of view. In this work, we explore how we can selectively recover these elements using aldoximes, particularly Ni in the presence of atomically similar elements such as Co, Mn, Zn, and Cu. We investigate the mechanisms of complexation for these metals and optimize operating conditions to extract these metals in a solvent extraction system. To mitigate the use of organic solvents, we aim to functionalize these ligand systems onto recoverable supports. We will investigate how different sizes of cores and grafting density affect the stabilities of the tethered aldoxime ligands and metal uptake efficiencies. These sorbents will be tested for two separation setups: in adsorption columns (for microscale particles) and magnetic separation (for nanoscale particles). The kinetics and thermodynamics of these setups can be understood to govern the design of metal recovery from different feedstocks. Finally, we also show that we can selectively electrodeposit Ni in the presence of competing ions with the use of these hybrid systems.