Enhancing Critical Material Recovery: Replacing Mixer-Settlers with Agitated Extraction Columns

D. Glatz, B. Cross
Koch Modular Process Systems,
United States

Keywords: critical material recovery, solvent extraction, rare earth elements


Ensuring a steady supply of critical minerals, metals, and rare earth elements (REE) is crucial for manufacturing most high-tech devices and clean energy technologies. To meet growing demand and mitigate supply chain disruptions, we need efficient, cost-effective recovery and purification processes. Solvent extraction (SX) is a proven technology whereby traditional mixer-settlers can be replaced, where practical, with agitated extraction columns. The benefits of transitioning from conventional mixer settlers to extraction columns include: • Cost Savings: One extraction column can replace over ten mixer settlers, significantly lowering installation costs. • Smaller Footprint: Extraction columns offer a compact footprint, maximizing space efficiency in processing facilities and can be more easily incorporated into exsiting facilities. • Reduced Solvent Inventory: The need for large solvent inventories is diminished, resulting in both CapEx and OpEx savings. The reduced solvent inventory inherently reduces the time to reach equilibrium or steady-state, resulting in faster process commissioning and production. • Improved Safety and Emissions: Enhanced safety measures and reduced emissions contribute to a more sustainable and responsible operation. • Emulsion Mitigation: Extraction column technology that can handle emulsification-prone processes yielding improved operational stability and less downtime. • Single Controlled Liquid-Liquid Interface: Extraction columns have a single controlled interface, yielding easier process control, reduced instrumentation and rotating equipment in comparison to mixer-settlers where each settler has a liquid-liquid interface. We intend to explore how extraction columns can replace mixer-settlers, offering more efficient and economical solutions for recovering critical materials such as lithium, cobalt, magnesium and REE.