CAREER: Rare Earth Elements Recovery from Nanoporous Ion-Adsorption Clays using Seawater

University Of Texas At Austin, Austin TX

Investigators

Abstract

Rare earth elements (REEs) are required materials in nearly all clean energy technologies that will enable the decarbonization of energy systems. For example, dysprosium is a heavy REE that is used to make the permanent magnets found in wind turbines and electric vehicles. Heavy REEs like dysprosium are the scarcest and most valuable, and they are produced predominantly from nanoporous ion-adsorption clay deposits. Current practices for REEs recovery from ion-adsorption clay deposits lack control over recovery rates and require enormous volumes of chemical solutions called leachates, which can result in severe ecological impacts. Environmentally-benign leachates such as seawater are a promising alternative for recovering REEs directly from ion-adsorption clay deposits. However, there is limited understanding of how these leachates interact with the nanoporous clay deposits to fundamentally control REEs recovery at scale. This project will explore the micro- and nano-scale mechanisms that control multiphase transport and sorption at nanoconfined water-air-clay interfaces, and relationships will be developed to inform upscaled, environmentally-benign REEs recovery from ion-adsorption clay deposits. The fundamental knowledge gained can also be translated to help understand similar processes in environmental remediation, battery science, and separations science. The research integrates education and outreach efforts to promote early-age exposure to science through the development of an interactive virtual reality application, where children take exploratory “rides” through a porous world. The goal of this CAREER project is to develop a fundamental understanding of the multiphase reactive transport phenomena that control REEs recovery from unsaturated, unconsolidated nanoporous clays using seawater as environmentally-benign leachate. A suite of novel micro- and nanofluidic imaging platforms will be developed that enable, for the first time, operando visualization of in situ fluid-solid interactions within nanoporous media. Quantitative treatment of micro- and nano-scale pore-level visualizations, including wetted reaction surfaces as a function of aqueous chemistry and the enhancement of reactive transport due to nanoscale electrokinetic phenomena, will be woven into pore-ensemble parameters, such as relative permeability and effective reaction kinetics, using reduced-order models to predict and design environmentally-benign and effective in situ leaching approaches. Optical and electron micrograph sequences of moving water-air-clay interfaces will be built into an interactive virtual reality world to engage school children in STEM learning activities. Through sensory play, the learning modules will build a basic intuitive understanding of the scientific principles associated with multiphase reactive transport in nanoconfined porous media. The application will be downloadable onto mobile phones at no cost, and application development will engage local K-12 classrooms in iterative feedback. Science teachers at the K-12 level will participate in a week-long professional development program focused on multiphase flow through porous media to assist in integrating the educational modules in their classrooms. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.