Recycling of lamp-phosphor residues for rare-earth-elements recovery using deep eutectic solvents
Rare earth elements (REEs) have been considered by the European Commission as the most critical raw material, considering both risk of supply shortage and impact on economy. The establishment of efficient REEs recycling technologies could significantly reduce the European Union import dependence. This project is an experimental approach to develop a close-loop process for the recycling of lamp phosphor powder based on a new brand of solvometallurgical technologies, i.e. solvoleaching and non-aqueous solvent extraction. The project is divided in three main technical parts: (1) selection of suitable deep-eutectic solvents (DESs) for the selective leaching of REEs from the lamp phosphor powder, based on solubility experiments using synthetic lamp phosphors, (2) optimization of the leaching process of real lamp powder waste and (3) selection of suitable extractants for the metal recovery from the leachate solution via non-aqueous solvent extraction and optimization of the latter. The obtained experimental data will be applicable not only to the recycling of lamp phosphor powder, but transferable to the recycling of other urban wastes such us cathode ray tubes or magnets. Non-aqueous solvent extraction from DES-based leachates is another non-explored and promising area, due the increased applicability of DESs in industrial processes.