Innovative pre-feasibility studies towards the sustainable production of rare earth concentrates for self-supply in Europe

The REESOURCE project aims to develop innovative technologies for extracting rare earths in Europe to secure the continent's self-supply and the resilience of the European REE value chains. Decarbonise the extraction of European REEs and bring the EU industry to the forefront of the sustainable local sourcing of raw materials. The present work in within the scope of work package 5-Greener beneficiation approaches for Zero-Pollution mining, aiming to develop novel formulations based on environmentally friendly chemicals for both, the mineral beneficiation process of REEs and the process water treatment, supporting the recirculation of this resource. Three samples from the Fen deposit in Norway were tested for physicochemical characterization, hydrogravitic preconcentration, and magnetic separation. This was followed by floatability tests, evaluating different reagent formulations and operating conditions. In all the tests, in addition to the recovery and content of the concentrates, special control was given to the water (quantity and quality) aiming at its recirculation. An advanced analytical method based on Ultra-performance liquid chromatography coupled to high resolution mass spectrometry (UPLC-HRMS) was developed to assess the different chemicals employed in the formulations at the flotation experiments. The technique allowed to better understand the efficiency of the substances in the beneficiation step, tracking the chemical transformation and/or byproducts of the targeted formulations (i.e organometallic substances) and to assess the reusability of the wastewater stream for flotation experiments. Additionally, the measurement of radionuclides and REEs was done over the samples. The results of the pre-feasibility studies are key to achieving the sustainable development objectives of the extractive industry for the supply of critical and strategic raw materials of Europe.