Functional composites based on refractories produced by pressure slip casting

The present study investigates the sequential pressure filtration of two filter cake layers with a maximum grain size of 3 mm and 1 mm, respectively, using a water soluble additive system consisting of xanthan and guar gum. The pressure slip casting of the resulting composites was optimized with a factorial experimental design. The best combination was a lower filtration pressure for the first filter cake layer and a higher filtration pressure for the second one. Furthermore, a shorter filtration time of the first filter cake layer together with the application of a filter aid of a xanthan/guar gum solution resulted in an easy demolding of crack-free graded composites with an excellent bonding. The results of the full factorial experimental design were verified by X-ray computed tomography. The demonstrated pressure slip casting of graded refractories offers the possibility to produce functional composites with tailored compositions, microstructure and thus functionality.