The Use of Mining Tailings as Analog of Rare Earth Elements Resources: Part 1 – Characterization and Preliminary Separation

Abstract

ABSTRACT The rapid depletion of high-grade rare earth elements (REE) resources implies that future supplies may be augmented with low-grade ores, mining tailings and other unconventional resources to meet cutoff grades and subsequently supply demands. In this work, detailed characterization of tailings from a copper processing plant was carried out to expand the knowledge of their chemical and mineralogical characteristics for REE recovery. The results showed that the REE are mainly mineralized as bastnäsite, monazite, and stetindite, along with uncommon minerals, such as brannerite, stillwellite, and florencite, for which there is limited processing data. In a preliminary effort to recover the REE, the tailings were subjected to gravity, magnetic, and froth flotation separation. Over 90% REE recovery was achieved via froth flotation, whereas magnetic and gravity separation tests recovered up to 86% and 54% REE, respectively. The results from this study suggest that, with systematic optimization studies, REE recovery and upgrade could be enhanced, with significant efforts of minimizing the recovery of key gangue minerals, such as goethite, hematite, and quartz. Overall, the study confirms that the tailings used in this work could be regarded as unconventional REE resources subject to tactical development and optimization of beneficiation methods.