Periodic Reporting for period 1 - GOSSAN (GOethite in Supergene Systems: ANalysing trace element substitution goethite and related iron oxides and oxyhydroxides.)
Período documentado: 2017-10-01 hasta 2019-09-30
The two years GOSSAN project (GOethite in Supergene Systems: ANalysing trace element substitution goethite and related iron oxides and oxyhydroxides) was aimed to the study of geochemical, morphological and structural composition of natural of iron oxides and oxyhydroxide in different types of Supergene Ore deposits (SOD). The main objective was the investigation of the behaviour of a range of economic metals commonly occurring in the primary ore deposits subjected to re-mobilization processes taking place during the weathering followed by their quantification within the natural oxides and oxyhydroxide, with major attention to the goethite. The main motivation for studying goethite as main mineral, is ascribable to several reasons: i) it is the most stable mineral among the Fe-oxi-hydroxides; ii) it is always present in the oxide zones of supergene ore deposits; iii) it is rarely pure: in fact, conspicuous amounts of cations isovalent or heterovalent to Fe3+ i.e. Ni, Zn, Co, REE, Sc, Ga, Ge, In, Pb, Hg, Mn, Cd, Si, Al etc. can substitute the Iron or be incorporated in the goethite structure (α-FeOOH). Some of the above mentioned metals were defined as “Critical Elements” by EU (https://ec.europa.eu/growth/sectors/raw-materials/eip_en/en/content/strategic-implementation-plan-sip-0) which remarked their importance in the new generation technologies and industrial development; on the contrary, other (i.e. Hg, Pb, Cd..) are considered as “problematic elements” in term of environmental and human health. Hence, an accurate knowledge of their behaviour, distribution and a systematically investigation on their occurrence in the mineral phases commonly present in SOD soils in addition to the definition of their economic potential is crucial for the modern and future society.
During the two years the researcher was able to perform detailed mineralogical and geochemical studies on a range of natural Fe- oxides and oxyhydroxide collected from a diverse range of supergene deposits. Many relevant samples were selected from mineral collections at the NHM, some have been identified as part of previous EU projects (NICAL, CENSZ) and the ongoing NERC project CoG3(http://www.nhm.ac.uk/our-science/our-work/sustainability/cog3-cobalt-project.html). Additional material was then collected in field by a sampling campaign on the Ni/Co-laterite deposit of Santa Fé de Goias, Brazil. All the planned analytical work was hence completed and divulgated. The study was carried out by the use of several analytical techniques (ICP/MS, SEM-EDS, EPMA, LA-ICPMS, XRD, TEM, EELS). The results of the analyses were presented and divulgated at International conferences as conference papers, poster and oral presentation (Goldschmidt 2018 and 2019, MDSG 2018 and 2019, SEG 2019) and seminars (NHM seminars and at University of Napoli, Federico II). In addition, one publication was presented on Minerals open access where the researcher is a co-author and another publication is under review for submission. During the two years period the researcher also collaborated with other Academic Institutions (University of Rio de Janeiro and University of Napoli) and private company (TESCAN Ltd.) and enhancing its network.
As planned, the main output was the achievement of a systematic study on the natural goethite and other associated Fe- oxides and oxyhydroxide associated with SOD ores and the an accurate definition of the base and Critical element deportment in the above mentioned phases and their economic potential. The main economic implications arising from the project outputs could hence impact the metallurgical industry as they can drive the future research in term of processing techniques through new developments dealing with the implementation of innovative hydrometallurgical and bioprocessing strategies in order to opens up neglected Fe- oxides and oxyhydroxide for metal recovery.