Possibilities of cross flow filtration during wet processing of alumina

In the field of technical ceramics extremely fine powders are used, which h ave to be dispersed completely and reproducible during preparation, Usually , this can be achieved only in a solid content range of 20...40 mass-%, whi ch is not economic in the spray drying or slip casting process. A further i ncrease of the solid content in ceramic suspensions using common :or techni ques like dead-end filtration or evaporation of Solvent leads to a reagglom eration of the dispersed particles and to structural damage of the organic aids. By cross-flow filtration high solid contents can be performed without any cake formation. It was demonstrated that a reversible flocculation of the ceramic particles (without additional flocculants) as well as the port by electric alternating fields results in an essential increase of solid co ntent up to 70 mass-%.