Mineralogical Studies in Assisting Beneficiation of Rare Earth Element Minerals from Carbonatite Deposits

Rare earth elements (REE) are either housed in exotic REE minerals that sporadically populate the host rock or they occur as ionic substitutions in the crystal structure of existing rock-forming minerals. The genesis of REEs in carbonatite rocks can result in intricate mineralogical textures between REE minerals, host rock minerals, and minerals formed by later processes. Upfront mineralogical assessment discloses these associations, in turn leading to correct metallurgical planning and providing early predictions in beneficiation testwork. The method recommended in this study utilizes X-ray diffraction (XRD), optical microscopy, and a conventional scanning electron microscope (SEM) with energy dispersive spectroscopy. The aim of the REE up-grading process is to provide the hydrometallurgist with a REE mineral concentrate where the total rare earth oxides (TREOs) exceed 40 mass%. Upgrading is based on firstly achieving the best liberation possible for all minerals and secondly using physical differences in minerals to concentrate the REE minerals.