Role of Sodium Citrate in Aqueous Milling of Aluminum Oxide

Abstract

A study was initiated to identify the mechanism(s) by which chemical additives affect aqueous milling of oxide suspensions. Properties of milled Al2O3 suspensions containing sodium citrate were correlated with ground‐powder characteristics. Maximum grinding efficiency was obtained at the sodium citrate concentration which resulted in the maximum (absolute value) zeta potential and the minimum suspension viscosity. The results indicate that sodium citrate indirectly affects comminution by altering the particle arrangements (state of dispersion) in suspension. Fracture strength measurements, determined on porous bulk Al2O3 samples pretreated in distilled water and aqueous sodium citrate solutions, did not support chemomechanical mechanisms.