Abstract :
[en] A new insight into the way in which the mineralogical composition and texture of sulfides govern the geochemical behavior of the tailings in terms of acid mine drainage (AMD) generation is presented. Two samples were taken from a tailings management facility. They were likewise subjected to flotation to recover reactive (liberated and middling) pyrite whilst the unreacted (locked) pyrite was kept in the tailings fraction. Geochemical (static and kinetic) tests were performed on the collected samples and tailings after flotation and a secondary electron microscope based automated mineralogy system (AM) was used to characterize them in terms of modal mineralogy, liberation degree and particle size. The absolute acidification potential (AP) defined by the Sobek method overestimates the effective AP when pyrite is partially locked. Hence, considering the locked pyrite may unfavorably lead to acidity overestimation and increased tailings management costs. Therefore, automated mineralogy data was used to calculate the effective AP of the tailings taking into account pyrite grade and its liberation degree. Based on the findings it could be assumed that the amount of lime required to neutralize the acidity produced by pyrite oxidation could be considerably reduced (in the studied case nearly 4 times) if environmental desulfurization by flotation is practiced and the liberation degree of the acid-producing minerals is taken into account.
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