Comparison between techniques based on charge characterisation and capillary suction time for assessing the dispersion characteristics of concentrated slurry

Achieving a stable dispersion with high solid loading is pre-requisite in many conventional/emerging ceramic forming processes. Hence, assessing the quality of dispersion is one of the critical aspects to be considered during forming process to ensure the final product quality. There are several direct/indirect techniques to assess the quality of dispersion. Many are optical methods, which generally require dilution of the suspension, with consequent alteration of the equilibria. This complicates the system unless particular care is taken to compensate for the dilution process. Many times it has been observed that a dispersant, that provides good dispersion at low solids concentration will not necessarily provide good dispersion at high solids concentration. This paper compares two indirect techniques, namely, particle charge detector (PCD) using the principle of 'Streaming Potential' and capillary suction time (CST) apparatus based on the principle of capillary suction pressure to study the effectiveness of a dispersant for maximum dispersibility. (C) 2004 Kluwer Academic Publishers.