title: Recovery of Rare Earth Elements and Yttrium from Passive-Remediation Systems of Acid Mine Drainage.
abstract: Rare earth elements and yttrium (REY) are raw materials of increasing importance for modern technologies, and finding new sources has become a pressing need. Acid mine drainage (AMD) is commonly considered an environmental pollution issue. However, REY concentrations in AMD can be several orders of magnitude higher than in naturally occurring water bodies. With respect to shale standards, the REY distribution pattern in AMD is enriched in intermediate and valuable REY, such as Tb and Dy. The objective of the present work is to study the behavior of REY in AMD passive-remediation systems. Traditional AMD passive remediation systems are based on the reaction of AMD with calcite-based permeable substrates followed by decantation ponds. Experiments with two columns simulating AMD treatment demonstrate that schwertmannite does not accumulate REY, which, instead, are retained in the basaluminite residue. The same observation is made in two field-scale treatments from the Iberian Pyrite Belt (IPB, southwest Spain). On the basis of the amplitude of this process and on the extent of the IPB, our findings suggest that the proposed AMD remediation process can represent a modest but suitable REY source. In this sense, the IPB could function as a giant heap-leaching process of regional scale in which rain and oxygen act as natural driving forces with no energy investment. In addition to having environmental benefits of its treatment, AMD is expected to last for hundreds of years, and therefore, the total reserves are practically unlimited.
authors.affiliation: Institute of Environmental Assessment and Water Research, CSIC , Jordi Girona 18, 08034 Barcelona, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Ayora
authors.affiliation: Department of Geology, University of Huelva , Campus "El Carmen" s/n, 21071 Huelva, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Macías
authors.affiliation: Institute of Environmental Assessment and Water Research, CSIC , Jordi Girona 18, 08034 Barcelona, Spain.
authors.forename: Ester
authors.initials: E
authors.lastname: Torres
authors.affiliation: Institute of Environmental Assessment and Water Research, CSIC , Jordi Girona 18, 08034 Barcelona, Spain.
authors.forename: Alba
authors.initials: A
authors.lastname: Lozano
authors.affiliation: Department of Geology, University of Huelva , Campus "El Carmen" s/n, 21071 Huelva, Spain.
authors.forename: Sergio
authors.initials: S
authors.lastname: Carrero
authors.affiliation: Department of Geology, University of Huelva , Campus "El Carmen" s/n, 21071 Huelva, Spain.
authors.forename: José-Miguel
authors.initials: JM
authors.lastname: Nieto
authors.affiliation: Department of Geology, University of Huelva , Campus "El Carmen" s/n, 21071 Huelva, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Pérez-López
authors.affiliation: Institut des Sciences de la Terre, CNRS and Université Grenoble Alpes , 1381 Rue de la Piscine, 38041 Grenoble, France.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Fernández-Martínez
authors.affiliation: European Synchrotron Radiation Facility , 71 avenue des Martyrs, 38000 Grenoble, France.
authors.forename: Hiram
authors.initials: H
authors.lastname: Castillo-Michel
mesh_terms: D000143:Acids; D008674:Metals, Rare Earth; D008906:Mining; D014874:Water Pollutants, Chemical; D015019:Yttrium
chemical_list: D000143:Acids; D008674:Metals, Rare Earth; D014874:Water Pollutants, Chemical; D015019:Yttrium