Dense Media Separation for Mineral Carbonation and Enhanced Rare Earth Mineral Recovery

Abstract Rare earth elements (REEs) play a significant role in a wide range of emerging green energy and defense applications. The increasing demand urges more REE production, thereby necessitating the development of new energy-efficient extraction processing technologies. This study investigated the use of dense media separation (DMS) as a preconcentration technique for sorting REE-bearing ores prior to the conventional beneficiation step. It was demonstrated that DMS can separate most REE-bearing carbonates into the sink fraction, while silicates are separated into the float fraction. Pretreatment effectively reduced the mass and hardness of the materials to be ground. As such, a total grinding energy saving, in some cases, of up to 79.77% and improved REE flotation performance can be achieved compared to the conventional approach. The DMS float fraction enriched with silicates was subjected to mineral carbonation, achieving a carbonation efficiency of approximately 26%. These findings provide compelling evidence that DMS can be used to develop a new energy-efficient REE extraction processing technique while simultaneously offering pathways for CO2 sequestration via the carbonation of gangue minerals.