Elucidation of Settling Enhancement Phenomenon during Applying a DC Electric Field to ‍Aqueous SiO₂ Slurry

Abstract

In our previous reports, it was shown that applying a DC electric field to an aqueous slurry can enhance the settling of particles. However, the mechanism of the particle settling enhancement by a DC electric field has not been fully elucidated. In this paper, we attempted to elucidate the mechanism by observing enhanced settling phenomena during applying a DC electric field to an aqueous SiO₂ slurry under various conditions, and by measuring particle diameters and pH before and after applying a DC electric field. As a result, it was found that particle settling enhancement phenomena when a DC electric field is applied to an aqueous SiO₂ slurry is caused by the particle-free region formed by electrophoresis, and its moving upward in the slurry due to the density flow generated by the horizontal density difference.