Characterization of rare earth ores from Ambatofinandrahana by X-ray diffraction and Zetametry for their bioleaching

Bioleaching is an extraction technique that uses microorganisms as a leaching agent.This method requires several bacteriological, physico-chemical and mineralogical analyzes of the ores, which in this study are the rare earths.The rare earths include the seventeen elements of the periodic table, including fifteen of the lanthanide family with yttrium and scandium.Two important parameters for the experimental process of rare earth bioleaching are studied, the first refers to characterization by X-ray diffraction (XRD).This is a valuable tool to identify the mineralogical composition of the ore, to determine the distribution rare earths in the ore and to follow the evolution of the leaching process.The second is the determination of the surface properties of the samples to be treated.This property is evaluated by the zeta potential technique.In order to choose and know the type of bacteria to be used, we need to know the surface charges and surface properties characterizing each ore to be leached.In this study, the samples come from the Ambatofinandrahana site.Ten samples were characterized by zetameter and XRD.The results show that all ores are negatively charged according to zetametry, hence the need for positively charged bacteria.As for the XRD results, the ores are mainly composed of bastnaesites and monazites.These two parameters make a major contribution to the upstream characterization of our ore samples prior to their actual bioleaching.