Speciation and transport of rare earth elements in passive treatment systems of the Iberian Pyrite belt

Rare Earth Elements (REE) are crucial to modern technological applications due to their unique chemical, optical and magnetic properties. Because of this very reason, the demand for REE has been increasing very rapidly since mid 90s. In fact, it is foreseen that the advancement in technologies would further increase the demand in the future as well. On this front, question arises as to whether available REE reserves in the world would be capable of catering to this increasing demand in long run. In addressing to this issue, researchers have found that acid mine drainage (AMD) water for example in Iberian Pyrite Belt (IPB) contains higher concentrations of REE (4000-80000 pmol/L) than those present in natural water bodies. Usually remediation of these AMD is achieved by passive treatment systems (PTS) established especially at abandoned mine sties in IPB. PTS has ability to neutralize AMD water and to enhance precipitation of heavy metals like Fe, Al, Pb etc. In IPB, Dispersed Alkaline Substrate (DAS) system is used as the PTS. Researchers have further found that the REE get immobilized in those DAS, PTS via sorption and co-precipitation to Basaluminite. However, the entire mechanism that lead to REE immobilization is still unknown. Therefore, this PhD is aimed at gaining in depth knowledge on the nature of retention mechanism of REE present in AMD of the IBP along PTS and to model it to describe the fate of REE within such PTS at IPB and possibly along PTS other than DAS in worldwide. Thereby to identify the potential in concentrating/remediating REE from AMD.