Processing of Korean monazite concentrat

Rare earth metals (REMs) have gained immense awareness due to their inimitable properties and wide range of applications. The present work focuses on a comparative study of the recovery of REMs from original and dephosphorized Korean monazite through acid treatment. A direct leaching approach utilizing dilute hydrochloric acid (HCl) at elevated temperatures for 2 hours with a pulp density of less than 100 g/L yielded a 25% dissolution of REMs from the original sample. This recovery increased to 45% with a two-step leaching method due to the phosphate present in the mineral that formed a complex with REMs, impeding their leaching. In contrast, over 93% of REMs was successfully leached from dephosphorized monazite under the same conditions. Systematic studies on the dephosphorization process were conducted using pyro/hydrometallurgical methods. Additional techniques such as precipitation, solvent extraction, and ion exchange methods were employed for the selective separation of REMs from the leach liquor produced. The methodologies and findings provide crucial insights into optimizing the recovery of valuable rare earth elements from complex mineral sources.