Effects of particle concentration and additive amount of dispersant on adsorption behavior of dispersant to alumina particles

We investigated the effects of particle concentration and an additive amount of a dispersant on the adsorption behavior of dispersant. Ammonium polycarboxylate, one of the typical polyelectrolyte was used as a dispersant in this study. Alumina slurries were prepared by changing the concentrations of both the particle and dispersant and kept in a test tube for at least 2 d. After that, the adsorbed dispersant amount was calculated from the residual dispersant concentration measured by a total organic carbon analyzer. It was found that the adsorbed dispersant amount strongly depends on the additive dispersant amount on the basis of the unit mass of particles in the slurry regardless of the particle concentration. It was also shown that pollycarboxylic acid strongly absorbs onto an alumina surface and can not be desorbed by dilution, suggesting that its adsorption behavior differs from physical adsorption. (C)2009 The Ceramic Society at Japan. All rights reserved.