Separation of radioactive elements from rare earth elements using precipitation technique
Adrián Carrillo García a, Mohamad Latifi b, Jamal Chaouki c
Dept. of Chemical Engineering, École Polytechnique de Montréal, C.P. 6079, Succ. Centre-Ville,
Montréal, QC, Canada, H3C 3A7
a
adrian-2.carrillo-garcia@polymtl.ca
b
mohammad.latifi@polymtl.ca
c
jamal.chaouki@polymtl.ca
ABSTRACT
The increasing demand of rare earth element (REE) due to their many applications, mainly in advanced
materials and new technologies, makes the research for its production attractive. However, its production is
mostly developed in China, while the rest of the world is a step behind in the process concerning the REE
production. The REEs are contained in minerals such as those investigated in this study, monazite and
bastnaesite. In such minerals, particularly monazite, the presence of radioactive elements such as thorium
and uranium is significant. In order to satisfy an eco-friendly production of REEs, Th and U must be
effectively separated.
In this study, to ensure this separation, first the concentrated mineral underwent an acid baking
followed by water leaching. As REEs, Th and U have similar physicochemical properties they all dissolve
in the same solution. In the next step, the selective precipitation of these radioactive elements was achieved
with an alkali reactant. The pH was the parameter that affects the most the precipitation to obtain the
highest recovery of Th and U in the precipitate. This made its optimization at ambient temperature an
important part of the process. However, it was also important to minimize the loss of REE during the
process. Once the pH determined, the study of the temperature was necessary, even if it affected slightly
the process.
KEYWORDS
Rare earth element, thorium, uranium, radioactive elements, precipitation