The influence of chamotte on densification and mechanical properties of ceramic membranes made from Gabonese kaolin

Abstract Porous ceramic membranes have been successfully prepared by roll pressing using low cost local raw materials. The porous ceramic membranes were obtained by sintering five ceramic paste formulations containing kaolin, rice husk and chamotte powders at a temperature range of 1100–1300°C. The fired ceramic membranes were characterized by determining their porosity, pore size, flexural strength and microstructure. The porous ceramic produced had a pore volume ranging from 27.3 ± 1.4 to 58.5 ± 0.5%, an average pore diameter from 4.7 ± 2.5 to 14.5 ± 1.3 µm and a mechanical strength from 0.8 ± 0.1 to 10.0 ± 0.6 MPa. The results show that the addition of chamotte increases the structural reorganization temperature of the composite, but does not affect the temperature range of densification and complete mullitization of the material. The random distribution of the inert phase (chamotte and quartz) induces a non-uniform behavior of the porosity, the average pore diameter and the mechanical strength after sintering of the samples. The characteristics of the porous materials obtained at 1300°C are adequate to be used in microfiltration.