Environmentally benign processing of ceramics by extrusion with various clay minerals as inorganic binders

Abstract

An environmentally benign extrusion process of ceramics was investigated by adding various clay minerals as inorganic binders to provide properties such as flowability and shape-retention, which are provided by organic binders. Ceramic pastes that contain smectite show excellent extrusion behavior and those that contain swelling mica show good extrusion behavior. The swelling property of clay minerals is considered to affect their extrusion behavior predominantly. In addition, the extrusion behavior of pastes prepared by adding wet gel containing swelled smectite is better than that of pastes prepared by adding dry smectite powder. In the paste prepared by adding wet smectite gel, the smectite becomes thin platelets and disperses homogeneously, as observed by using electron microscopes. Therefore, the addition of smectite under wet gel conditions is considered to be more effective in improving the extrusion behavior.