PROPERTIES AND MICROSTRUCTURE OF POROUS CERAMICS FROM DIATOMITE

Porous ceramics have been used extensively in liquid or gas filtration and as thermal insulation. In this study, a porous ceramic was fabricated using diatomite by roller pressing technique. The diatomite was intensively mixed with methylcellulose in water that was premixed with some plasticizers. Glaze was used in the mixture as high temperature bonding agent for the diatomite powder. The pressed specimens were dried at 110°C and subsequently subjected to heat treatment from 900°C to 1100°C, with one hour soaking time. The sintered specimens were evaluated for shrinkage, bulk density, modulus of rapture and porosity. The microstructural changes during sintering were determined by using scanning electron microscopy. High porosity of > 65% were obtained for most specimens, which is suitable for filtration of water under gravitational force. By controlling the sintering temperature, the pore and the strength of the ceramics can be manipulated to the required filtering applications. The primary advantage of using this method is the potential for economical mass producing of filters.