Summary:
The studied Fe-Ni ore deposits in the Lokris area are allochthonous karst type deposits (formed by transportation and redeposition of laterite derived material, over karstified limestones). These are the Kopaida, Tsoukkas and Nisi open-pit mines.
Nickel-rich minerals of Lokris Fe-Ni ores, according to existing literature, are mainly hydrated silicate minerals, such as nickel chlorite, nickel-smectite as well as other phases, whether or not characterized. Thus, the purpose of this thesis is a detailed mineralogical and geochemical investigation of the distribution of nickel and cobalt in the various mineralogical phases of the G..M.M.A.E LARCO open pit mines in the Lokris area. We emphased on the goethite and silicate phases to estimate the percentage of nickel that participates in the hydroxides. Also are presented two types of garnierites in the region of Lokrida. The first type is at the southeastern sector at position 281 in the Agios Ioannis inactive open pit mine and the second type is at the area of Votta. They are responded in the form of either vein material crossing the disintegrated serpentinite or as granules in the disintegrating sector of the saprolite.
Laterite samples were collected from open pit mines in Lokris area (Kopaida, Tsoukka, Nisi) and was conducted applying multi-acid digestion, sequential extractions and analysis by Flame Atomic Absorption Spectroscopy (F-AAS) and spectrophotometry in order to evaluate the percentage of nickel that participates in the hydroxides.. The association with the different mineral phases of the soil was verified using powder x-ray diffraction (P-XRD) and scanning electron microscopy (SEM) techniques.
Given the results from sequential extraction it can be concluded that the percentage of nickel in the silicate phases is overestimated and the corresponding proportion in the iron phases is underestimated. So according to the sequential extraction (Table S4) we conclude that the nickel content of the iron phases is 32% (varies from about 22.4 to about 43.0 %) and not 16% as we known according to the existing literature. Also, cobalt (Co) shows lower levels of oxides in the sequential extractions as cobalt is in the silicate phases as well as in the asbolane.
Keywords:
nickel-iron ores, nickel minerals, laterite, garnierite, Lokris
