(611f) Electrostatic Charging and Entrainment Behaviors of Binary and Quaternary Particulate Systems in Fluidized Beds

A wide range of fluidization processes involve binary or quaternary particulate systems with different sizes and densities. The fluidization and entrainment behaviors of such systems would be significantly impacted by interparticle forces including the electrostatic force. During the operation of multiphase systems such as fluidized beds, electrostatic charges are generated primarily via triboelectric or frictional charging due to the dielectric nature of materials. The accumulation of the electrostatic charge within the system can lead to agglomeration of particles and in some cases can be operationally hazardous. In this study, the electrostatic charge generation and accumulation are investigated for binary and quaternary particulate systems using a faraday cup system and an on-line electrostatic probe system. Specifically, the effect of adding smaller iron ore particles (i.e., hematite and magnetite) into the bed of coarser iron ore particles is studied in terms of particle-particle interactions, electrostatics, and entrainment rates. The behaviors of different particulate systems are found to highly depend on the chemical and physical properties of particles such as chemical composition, size, density, hydrophobicity/hydrophilicity, surface roughness and even magnetism. The results suggest that the electrostatic forces between fine and coarse iron ore particles may have led to reduced entrainment of the fines.