| Abstract Scope |
With the increasing trend toward a circular economy aiming to balance sustainability, efficiency, and environmental impacts, this research focuses on identifying the best deep eutectic solvents (DES): a combination of hydrogen bond acceptors (HBA): choline chloride (Ch) and guanidine hydrochloride (Gu), and seven hydrogen bond donors (HBD): oxalic acid (OA), urea (Ur), ethylene glycol (Eg), lactic acid( LA), maleic acid (Me), malonic acid(MA), and glycerol (Gly) to leach REE from their complex ore which are proven to be green, selective, non-toxic, biodegradable, and inexpensive. REE are valuable for many modern technological applications, including metallurgy, instrument engineering, nuclear engineering, and manufacturing. The effects of 14 different DES combinations, temperature, and time on REE leaching efficiency were determined. The DES with the highest recoveries were found to be Gu-OA-Ch, Gu-MA, Ch-LA, Oxaline (Ch-OA), Gu-Gly, Ch-Me-Eg, Reline (Ch-Ur), and Gu-LA, with leaching efficiencies between 80%-99% recovery achieved for cerium, neodymium, praseodymium, and lanthanum.
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