Development of Solid Phase Extraction Process for Selective Separation of Scandium and Iron from Aqueous solutions
Video Engineering 2025 Graduate ExhibitionPresentation by TRIVENI GANGADARI
Exhibition Number 500
Abstract
Scandium (Sc) is a critical rare earth element vital for aerospace, fuel cells, and advanced technologies. With limited primary sources, it is often recovered from secondary resources such as waste streams from titanium, aluminum, and nickel production. However, these sources contain high levels of impurities, particularly iron (Fe), which shares similar chemical behavior with Sc in aqueous solutions, making selective separation challenging. Conventional methods like solvent extraction and precipitation are not only chemically intensive but also struggle with selectivity, highlighting the need for more efficient and sustainable recovery techniques. This study explores sustainable solid-phase extraction (SPE) using anion exchange resins (MTA 5011, MTA 1930) with quaternary and tertiary amine groups to selectively adsorb Fe complexes (FeCl4) while Sc remains as ScCl2. The difference in Fe and Sc speciation, created by adding excess chloride ligands to the solution and confirmed by spectroscopy and modeling, drives selectivity. Kinetic studies show Fe adsorption is chemically controlled, with resins demonstrating high capacities (125 mg/g for MTA 5011, 105 mg/g for MTA 1930). Optimized conditions yield selectivity factor values of 1300 for Fe over Sc and 90% desorption efficiency in two cycles with deionized water. Resins retain performance over multiple cycles, highlighting their industrial potential for Sc separation and broader rare earth element applications. This approach offers a greener, more efficient alternative to traditional Sc extraction methods, addressing sustainability challenges in critical element recovery.
Importance
Scandium is a critical element used in aerospace, clean energy, and advanced technologies, yet its recovery remains inefficient due to the presence of impurities like iron. Traditional extraction methods are chemically intensive and lack selectivity, making sustainable alternatives essential. This research introduces an innovative solid-phase extraction approach that effectively separates scandium from iron using ion exchange resins, significantly improving efficiency and environmental sustainability. By providing a greener alternative to conventional methods, this work contributes to the responsible recovery of critical materials, supporting advancements in technology and reducing reliance on scarce primary sources. The findings have broad implications for rare earth element separation, promoting sustainability in critical mineral extraction.