Chemical activation of clay raw material

Abstract

The starting clay raw material containing a high mass % of carbonates, presents an inadequate mineral composition for designing a resistant ceramic microstructure facing the attacks of aggressive wet environment. In the presence of the polymeric additive, during the thermal process of ceramic roofing tiles, a new microstructure has been designed. The thermal decomposition of the carbonates is activated, due to the induction of the structural defects during swelling phenomenon of the polymeric additive. The earlier appearance of CaO component brings about a better interaction of this phase with alumina-silica matrix. The formation of Ca-crystals, akermanite and diopside, is promoted and the mass % of ceramic matrix, mostly responsible phase for the chemical corrosion phenomena, is greatly decreased. © 2002 Trans Tech Publications, Switzerland.