Comparative Study on the Effects of Calcination Temperature of Kaolin Clay on the Fabrication and Properties of Ceramic Membranes

This study presents the development and optimization of multilayer porous ceramic membranes for microfiltration, using kaolin as both the functional microfiltration (MF) layer and the macroporous support. A common challenge with tubular supports made from extruded raw kaolin is deformation during drying. To overcome this, kaolin calcination was investigated as a processing strategy. Pre-calcination prior to shaping significantly reduced shrinkage and deformation, thereby improving the structural integrity of the supports. The calcination temperature was found to be a key parameter, influencing support quality, enlarging the average pore size, and enhancing water flux—achieving up to a fivefold increase compared with uncalcined samples. Furthermore, the effect of sintering temperature on porosity, pore size distribution, and mechanical strength was systematically examined. The fabricated MF membranes exhibited an average pore size of ~ 0.5 µm. Filtration tests with distilled water demonstrated their suitability for tangential microfiltration applications.