Mineralogical characterization and geochemical behavior of rare earth elements from a carbonatite deposit

摘要

The paper will focus on the geochemical characterization of the Montviel carbonatite deposit, located in Quebec (Canada). The five main lithologies of the deposit (ore and waste rocks) were sampled, characterized, and submitted to kinetic testing in order to investigate their REE leaching potential. A REE concentrate was also prepared from the ore sample using a combination of gravimetric and magnetic methods. All samples were submitted to a Qemscan analysis coupled to EPMA (electron probe microanalysis). These results indicate that the main REE bearing minerals are burbankite, Kukharenkoite-Ce, monazite, and apatite.The geochemical behavior of the waste rocks and ore samples was studied using humidity cells while a weathering cell (small-scale humidity cell) was used for the REE concentrate. The kinetic testing results show that low concentrations of light REE are leached (8.8-139.6 μ.g/1 total light REE) from the materials. These results are explained by a low reactivity of the REE bearing carbonates in the kinetic testing conditions, and by precipitation of secondary REE minerals.