Abstract
We prepared alumina slurries containing the same additive amount of dispersant in various solid concentrations, and observed gravitational settling behavior. Here, the additive amount is defined as the added dispersant mass per unit particle mass. Ammonium polycarboxylate was used as a dispersant. It was found that the settling behavior critically changes at a certain solid concentration and an additive amount of dispersant ; For the flocculated slurries, the settling behavior changed over 20 vol%, all particles in the slurry formed a network structure. The assembling state of particles in the slurry changed from strongly flocculated to well dispersed by small increase of additive amount of dispersant. It was also found that slurries, which have the same additive amount of dispersant, show the same settling behavior. From these results, it was shown that the settling behavior of particles can be dominated by not the dispersant concentration but the additive amount of dispersant.
