Comparative Study on the Influence of Collector Type and Dosage on Rare Earth Mineral Flotation

Rare earth elements (REEs) are essential components in technologies ranging from clean energy and electric vehicles to defense, healthcare, and electronics. Common rare earth minerals (REMs), such as bastnäsite (Ce, La, Nd, Y)(CO 3 )F) and monazite ((Nd, La, Ce)PO 4 ), are often associated with carbonate gangue minerals, including calcite (Ca(CO 3 )) and dolomite (CaMg(CO 3 ) 2 ). Flotation is one of the main method in beneficiation of such ore, and utilize mainly collectors from carboxylates, hydroxamates, and organic phosphoric acids groups. In this work, the performance of hydroxamates, carboxylates, and phosphoric acid esters in the flotation separation of REMs from the Fen carbonatite complex was studied through batch flotation tests at varying collector dosages. The other aim was to investigate the influence of gangue minerals on flotation performance. Flotation results were discussed in the context of existing literature, which predominantly focuses on pure minerals, with a few studies on real ore systems. Among the collectors tested, the alkyl hydroxamate demonstrated the highest selectivity for the investigated ore, whereas sodium oleate and phosphoric acid did not show potential for separation. At a dosage of 2715 g/t of alkyl hydroxamate, an optimal balance between recovery (95%) and selectivity was achieved at pH 8.5, characterized by high REMs recovery and low gangue recovery. The observed selectivity is proposed to be attributed to the strong chemisorption of hydroxamates onto REE cation sites via the formation of stable chelate complexes.