Plastic behaviour of different ceramic pastes processed by extrusion

A preliminary characterization of the plastic behaviour of several industrially-prepared ceramic pastes is presented, which was performed in order to gain some insights for preparing ceramic formulations Al-rich sludge-containing adapted for extrusion forming. Stress-deformation curves obtained by compression had been performed and related with the different types of ceramic formulations and their moisture contents. Deformation amplitude and rupture stress revealed the most sensitive parameters, thus giving valuable information about the plastic behaviour of ceramic pastes, as well as important guide lines to design extrudable formulations containing. The stress-deformation curves obtained with common industrial pastes are reproducible and relative differences are determined by the composition and amount of added water. The extrusion of fully recycled formulations made of Al-rich anodising sludge was found possible, but further improvements in working conditions should be achieved.