Retention Mechanisms of Rare Earth Elements and Yttrium (REY) from acid mine drainage
a cargo de: Alba Lozano
Día: Jueves 09 de Marzo a las 12:15 h
Lugar: Departamento de Ingeniería del Terreno, Aula CIHS, Planta Baja
Rare Earth Elements and Yttrium (REY) are critical raw materials which are essential for modern technologies. They are conventionally mined from igneous rocks from China, and they are now a priority exploration target worldwide. One of the research goals through the European ERAMIN-AMDREY project and the Spanish EMPATIA project is the extraction of REY from the treatment of Acid Mine Drainage (AMD) waters.
Laboratory experiments simulating AMD treatment were performed in columns to better understand the geochemical and mineralogical processes that play in the remediation systems and to determine where REY are retained. The evolution of pore water composition inside two columns revealed that REY content decreased together with Al concentration at pH higher than 4. Sequential extractions of precipitates confirm that the majority of REY are removed in Al zone where basaluminite precipitates (Al4SO4OH10·5H2O). This suggests that REY can be sorbed and coprecipitated with basaluminite.
Different batch sorption experiments were carried out to study REY sorption on basaluminite. Since Lanthanide (Ln3+) aqueous speciation in AMD waters with high SO42- concentrations are dominated by LnSO4+ complex, a first hypothesis is that REY are incorporated as LnSO4+. Synchrotron based experiments were performed in order to elucidate the binding mechanism of REY into basaluminite by EXAFS measurements, in Ln-SO4 solutions and in REY-doped basaluminites.