AM Antão, A Carolino - European Geologist European Geologist - eurogeologists.eu
1. Department of Civil Engineering, Polytechnique Institute of Guarda, Portugal
2. CEO of Pegmatítica -Soc. Mineira de Pegmatites, Lda. Portugal
Societal concerns with environmental questions and sustainability are priority issues; the exploitation of lithium cannot be carried out without considering environmental issues. The H2020 (IC&DT) Project LÍTIO is a joint project between a mining company, three polytechnics and the national professional association of geologists intended to create value for natural endogenous resources associated with territorial innovation in the mining district of Gonçalo. Its aims are preservation and sustainability of lithium through the development of a product, processes and services, environmental monitoring and innovative proposals for regional tourism promoting the mining area.
Lithium is an alkaline metal with the atomic number three. It is the lightest metal on Earth, as well as the least dense solid element. Lithium is a rare metal in the Earth’s crust and never occurs freely in nature. Its main sources are the minerals lepidolite, petalite, amblygonite, zinnwaldite and spodumene. Lithium is commercialised as a concentrated mineral in various chemical compounds (particularly in the form of carbonate or hydroxide). Lithium applications are increasingly diverse: it is used in ceramic and glass production, metallurgy of aluminium, manufacture of synthetic rubber and of lubricants, the process of purification of air in confined environments, in batteries as lithium bromide, and as lithium carbonate it is used in the pharmaceutical industry for the treatment of depression. With the increase in demand, and the consequent rise in the price of lithium, especially of the compounds used in the manufacture of lithium batteries, lithium carbonate and lithium hydroxide, pegmatite deposits are becoming cost-effective sources of lithium. After having secured the best pegmatite deposits in their countries, Australian and Canadian prospecting and research companies (P&R) began the study of other deposits of lithiniferous pegmatites occurring in Europe and particularly in Portugal, which is one of their P&R bases. The year 2016 was a year of excellence in the emergence of numerous ‘young companies’ around the world that together with traditional industrial companies operated not only from hard rock, but also from lithium exploration of salar brines. In 2017 Portugal ranked in sixth place worldwide and first in Europe in the mining production of lithium (USGS, 2018).
Lithium in Portugal
One of the largest lithium deposits belts in Europe is located on the Iberian Peninsula (Figure 1). These deposits are essentially lithiniferous pegmatite bodies that outcrop in metasedimentary rocks and granitoids of Variscan ages, along a zone of NNW-SSE direction in Galicia-Trás-os- Montes Zone (GTMZ) and Central Iberian Zone (CIZ) (Roda-Robles et al., 2018; Farinha Ramos, 2007). The National Government, aware of the potential existing in the country, announced the establishment of a working group at the end of 2016 (Declaration No. 15040/2016 of 13 December 2016), with the mission to identify and characterise all of the lithium deposits in Portugal, as well as to evaluate the possibilities of their prospecting and exploitation. This group produced a final report in March 2017 (Report, 2017), which identified nine geological zones with lithiniferous potential in Portugal (Figure 2).
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