| Grant number: | 19/12022-5 |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |
| Start date: | March 01, 2020 |
| End date: | September 30, 2021 |
| Field of knowledge: | Agronomical Sciences - Agronomy - Soil Science |
| Principal Investigator: | Tiago Osório Ferreira |
| Grantee: | Fabio Perlatti |
| Host Institution: | Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil |
Abstract Niobium (Nb) is a relatively rare metal in the earth's crust, which has attracted attention given its extraordinary physicochemical properties. Although there are many ongoing researches around the world in search of new technological applications for the metal, there is a complete lack of knowledge about the geochemical behaviour of Nb in natural and mining environments. Also is scarce the knowledge about the possible deleterious effects that Nb can cause to biota. In Brazil, responsible for approximately 93% of the global production, the metal is mainly extracted from deposits of Pyrochlore [(Na, Ca) 2Nb2O6 (OH) F)] and Columbite-Tantalite [Fe, Mn] (Nb, Ta), and with the growing demand for the mineral, ambitious and disorderly exploitation grows. In Brazilian amazon, where are found the largest Nb reserves associated with Columbite mineral, an increase in artisanal mines (also called "Garimpos") that exploit the ore has been occurring, as well as artisanal mining in cassiterite mining wastes areas, due to tailings rich in columbite. In such places, it is common to observe mine wastes disposed at open pits, without any technical criteria, which may cause the accumulation of high levels of Nb in soils, with eventual translocation to the biosphere. The same condition occurred in the Penouta mine, located in Galicia (NW, Spain), which has been exploited since 1906 for cassiterite extraction, but was abandoned in 1985, leaving a legacy of millions of tons of wastes at open pit, rich in Sn-Nb-Ta bearing minerals. In this context, the objectives of this work is to understand the biogeochemical behaviour of Nb and its relationships with the environment, through the evaluation of the metal speciation in mine wastes and soils, obtained by the sequential extraction technique in two different environments (tropical and temperate). As results, we expect to elucidate the main geochemical mechanisms that affect Nb mobility, leading to an unprecedented understanding on the ways of dispersion and control of the metal in the environment. (AU) | |
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