Ore Characterization and Its Application to Beneficiation: The Case of Molai Zn-Pb±(Ag,Ge) Epithermal Ore, Laconia, SE Peloponnese, Greece

This study provides a comprehensive characterization of the low-to-intermediate sulfidation (LS-to-IS) epithermal Molai Zn-Pb±(Ag,Ge) ore (Vigla-Mesovouni orebody) in Laconia, Greece, and provides insights on how such data may be employed in beneficiation flow-sheet design. Detailed mineralogical, chemical, textural, and physicochemical characterization defines a systematic transition from early refractory Ge-rich to late-stage refractory Ag-rich mineralization, including sulfides and fahlores. Germanium, although present in all sphalerite varieties (Sp-I, Sp-II, and Sp-III), is predominantly enriched in early sphalerite (Sp-I, up to 1891.60 ppm). Interestingly, Ge is also enriched in early Py-I pyrite, with content reaching up to 383 ppm. Silver is mainly concentrated in late-stage tetrahedrite Ttr-II (up to 3.60%), galena (Ga-II), and, to a lesser extent, late sphalerite (Sp-III). Liberation studies reveal effective liberation of Py-I and Sp-I, major Ge carriers, in the coarser fractions (+0.150 mm) and near complete liberation of all ore phases below 0.036 mm. Combined beneficiation via Wilfley pre-concentration and differential flotation produced up to ~35% Pb and ~65% Zn at >85% recovery for the smallest fractions (−0.036 mm). Ore characterization revealed that secondary circuits may be developed to further enhance the economic value of Molai ore (Ge from Py-I, and Ag±[Sb,As] from Ttr-II and Ag-bearing sulfosalts), which are dismissed as wastes in Pb and Zn flotation circuits. The results of our study establish a robust foundation for the design of tailored, multi-stage metallurgical flow-sheets aimed at maximizing the economic value of the Molai epithermal resource.