The Impact of Milled Alumina Particle Size and Distribution on Packing Efficiency and Paste Extrusion Pressures

Abstract

This body of work was focused on understanding particle size, distribution and the resulting packing efficiency's impact on the rheological properties of a plasticized batch. Tabular alumina was used as the single inorganic particle source for reduced complexity in the experimental design. The goal was to determine the effect of packing efficiency on the critical liquid level required to provide capillary flow with a desired material stiffness. It was found that with particles greater than 5 microns, the excess water necessary for easy flow was between 4-8% independent of packing efficiency. The resulting stiffness in the plastic body, however, increased exponentially with increasing packing efficiency. This experimentation has shown that in a system where minimal pressures due to material yielding are necessary, while maximum extruded body stiffness is also desired, then increased packing efficiency of inorganic particles achieves both these traits.