Yield Stress and Zeta Potential-PH Behaviour Of Washed Spherical a-Al ₂O ₃  Particles With Anionic Additives: Particle Force and Chembio 3d Simulation

Abstract

The yield stress- and zeta potential-pH behaviour of washed spherical α-Al2O3 suspension with and without three typical anionic additives were characterized. The zero zeta potential or isoelectric point(IEP) of washed α-Al2O3 particles locates at pH~9.5. With the increased dosage of the anionic additives, IEP moves to a lower pH range. The maximum yield stress of 50wt% α-Al2O3 suspension decreases from 78.3Pa to 50Pa by about 36% when citric acid is 0.2dwb%. According to the simulation of the MM2 model, the type of O-H···O hydrogen bond existed in the CA molecule which results in a stable steric repulsive effect. The pH range where yield stress exists also moves to the lower pH with the addition of anionic additives. However, the addition of Diisobutylene-maleic anhydride sodium salt and Polystyrene sulphonic acid sodium salt increase the maximum yield stress because of the specific attraction force, hydrophobic attraction force and charge attraction force.

Keywords: α-alumina, anionic additives, particle force, Zeta potential, yield stress