Characterization of Fe biominerals for developing rare earth element capture and separation strategies
EMSL Project ID
61061
Abstract
Rare earth elements are increasingly used in green energy, e.g. in wind turbines and electrical vehicles, as well as in defense technologies and consumer products. Domestic mining efforts struggle to meet increasing demands and securing a reliable supply of REEs is a top priority for both the economy and national security. Many researchers are turning to the circular economy and waste streams to develop more sustainable supplies of REEs. Acid mine drainage (AMD) is a promising domestic source of REEs, but, to develop this source, we need more economically feasible ways to concentrate and recover REEs from AMD. Microbial Fe oxidation may provide a promising solution. Fe oxidizing bacteria colonize AMD outflows where they produce copious Fe biominerals as byproducts of their metabolism. These highly reactive biominerals concentrate REEs through sorption processes. By investigating the reactivity of Fe biominerals towards REEs and optimizing desorption methods we aim to generate an enriched, valuable source of REEs.In our current ONR-funded project, we are optimizing REE recovery with Fe biominerals via a combined approach of geochemical modeling and adsorption/desorption experiments. So far, our work shows that naturally occurring Fe biominerals found in AMD are highly reactive towards REEs. We also demonstrated that mild acid leaching and thermal aging are promising, sustainable methods of recovering REEs from Fe biominerals. However, natural biominerals are heterogeneous, so we do not yet fully understand the mechanisms of REE sorption. To that end, we propose to characterize the mineralogy, particle size, and texture/spatial relationships of Fe biominerals. We will use high resolution TEM to explore the mineralogy of surfaces accessible and reactive towards REEs (likely nanoparticulate iron oxyhydroxides), and how this changes with thermal aging. Mössbauer spectroscopy will be performed to help identify and quantify discrete mineral phases. CharacterizingFe biominerals at the atomic scale will help us to understand REE sorption in order to help improve REE recovery parameters, develop more sustainable extraction procedures and generate a rich REE source from otherwise low-grade AMD waste streams.
Project Details
Project type
Limited Scope
Start Date
2024-01-29
End Date
N/A
Status
Active
Released Data Link
Team
Principal Investigator