Extrusion and visualization of clay pulp through orifices-Application to the ceramic [Extrusion et visualisation des pâtes d'argile au travers des orifices-Application à la céramique]

In this study,the results of the experiments obtained by the extrusion of three types of clay in the plastic state are presented. two clays are in the rough and the third is a treated clay. a new original device which simulates the operation of a piston extruder has been developed. this device allows to study paste extrusion through orifices calibrated by applying pressure using a standard piston. several phenomena and defects can occur. these are related to the influence of certain parameters such as the nature of the materials,the geometry of the die,the pressure exerted and the extrusion speed. the observation of the morphology of the extrusion has made it possible to see the water migration from the center to the walls. the rheological parameters were also determined for various concentrations near the plastic limit.