@article{3031089,
    title = "Origin of Critical Metals in Fe-Ni Laterites from the Balkan Peninsula:
Opportunities and Environmental Risk",
    author = "Economou-Eliopoulos, Maria and Laskou, Magdalena and Eliopoulos, and Demetrios G. and Megremi, Ifigeneia and Kalatha, Sofia and Eliopoulos, and George",
    journal = "Minerals",
    year = "2021",
    volume = "11",
    number = "9",
    publisher = "MDPI",
    issn = "2075-163X",
    doi = "10.3390/min11091009",
    keywords = "Fe-Ni-Co laterites; critical metals; REE; PGE; Cr(VI) contamination",
    abstract = "As the global energy sector is expected to experience a gradual shift
towards renewable energy sources, access to special metals in known
resources is of growing concern within the EU and at a worldwide scale.
This is a review on the Fe-Ni +/- Co-laterite deposits in the Balkan
Peninsula, which are characterized by multistage weathering/redeposition
and intense tectonic activities. The ICP-MS analyses of those laterites
indicated that they are major natural sources of Ni and Co, with ore
grading from 0.21 to 3.5 wt% Ni and 0.03 to 0.31 wt% Co, as well as a
significant Sc content (average 55 mg/kg). The SEM-EDS analyses revealed
that fine Fe-, Ni-, Co-, and Mn-(hydr)oxides are dominant host minerals
and that the enrichment in these elements is probably controlled by the
post-formation evolution of initial ore redeposition. The paucity of
rare earth element (REE) within the typical Fe-Ni laterite ore and the
preferential occurrence of Co (up to 0.31 wt%), REE content (up to 6000
mg/kg sigma REE), and REE-minerals along with Ni, Co, and Mn (asbolane
and silicates) towards the lowermost part of the Lokris (C. Greece)
laterite ore suggest that their deposition is controlled by epigenetic
processes. The platinum-group element (PGE) content in those Fe-Ni
laterites, reaching up to 88 mu g/kg Pt and 26 mu g/kg Pd (up to 186 mu
g/kg Pd in one sample), which is higher than those in the majority of
chromite deposits associated with ophiolites, may indicate important
weathering and PGE supergene accumulation. Therefore, the mineralogical
and geochemical features of Fe-Ni laterites from the Balkan Peninsula
provide evidence for potential sources of certain critical metals and
insights to suitable processing and metallurgical methods. In addition,
the contamination of soil by heavy metals and irrigation groundwater by
toxic Cr(VI), coupled with relatively high Cr(VI) concentrations in
water leachates for laterite samples, altered ultramafic rocks and soils
neighboring the mining areas and point to a potential human health risk
and call for integrated water-soil-plant investigations in the basins
surrounding laterite mines."
}