Does the Zeta Potential of an Iron Ore Concentrate Affect the Strength and Dustiness of Unfired and Fired Pellets?

© 2017 Taylor & Francis. We show how pelletizing additives affect the zeta potential, sedimentation and agglomeration behavior of a hematitic iron ore concentrate. When the additives stabilized the particle–water system—indicated by higher zeta potential, higher total suspended solids content and denser settled sludge—pellet strength increased and dustiness decreased. Conversely, when the additives destabilized the particle-water system—indicated by lower zeta potential, lower total suspended solids content and rarer settled sludge—pellets became weaker and dustier. Specifically, our results show that problems related to starch binders can be resolved using carefully selected dispersants, and starch-dispersant mixtures are better pellet binders than starch alone. In general, our results suggest that sedimentation and zeta potential tests may be effective techniques for understanding pellet–water–binder systems; organic dispersants are good alternatives to bentonite for making low-silica binders; and understanding surface properties and water chemistry of the balling feed is necessary to understand its agglomeration behavior. We believe that understanding the interactions between the balling feed minerals, pore water, and binder will become more important as balling feeds become finer and process waters more complex