Depresión de pirita durante la flotación sin colector usando propionato de calcio

Iron disulfide (FeS2) is often found associated with economically valuable metal sulfides; pyrite is considered a gangue mineral, and efforts are made to prevent it from floating alongside the valuable sulfides. However, its inherent nature makes it naturally hydrophobic, leading to flotation. To alter these properties, the mining industry employs sodium cyanide and lime to form ferrocyanide, which imparts partial hydrophilicity; nevertheless, pyrite remains abundant in the concentrates. Furthermore, the continuous use of toxic substances like cyanide poses environmental and health risks. Therefore, this study proposes calcium propionate (PPC) as an organic depressant for pyrite, evaluating the effect of PPC dosage at pH 7.0 during the flotation of a single phase pyrite ore. The results indicate that increasing the amount of PPC in the flotation pulp progressively improves the surface depression of the disulfide; specifically, PPC concentrations of 5 and 6 g/L successfully depress the pyrite surface, resulting in a concentrate containing only 15% pyrite, whereas the absence of PPC in the pulp leads to uncontrolled pyrite flotation, reaching a maximum of 80%. The conversion of the surface from hydrophobic to hydrophilic is attributed to the formation of iron propionate on the mineral Surface confirmed via FTIR análisis which prevents absorption onto flotation bubbles and causes the mineral to remain in the pulp rather than floating.