Preparation process of a highly resistantanorthite based ceramics using local raw materials: Effect of Na2CO3 additions on sintering and crystallization

Abstract

Anorthite (CaO·Al2O3·2SiO2) is mainly used for traditional ceramics. In this study, anorthitebased ceramics was obtained by solid state reaction.The new selected composition was80 wt.% kaolin (DD2 type) and 20 wt.%calcium oxide (CaO) extracted from CaCO3. The choice of these raw materials was dictated by their natural abundances. Moreover, different amounts of Na2CO3(0.5-3.0 wt.% ) have been added in order to promote densification and lower down its sintering temperature. Optimizing the main parameters controlling anorthite based ceramics production such as milling techniques, compacting pressure, sintering temperature and holding time may lead to better anorthite based ceramics. The prepared samples were sintered at different temperatures ranging between 800 and 1100 °C for 1 h. A relative density of about 97% of the theoretical was reached for samples containing 3 wt.%Na2CO3 sintered at 1000 °C for 1 h. A porosity ratio of about 4% for samples containing 3 wt.%Na2CO3 sintered at 1000°C for 1 h.Finally, these fabricated products were also characterized byscanning electron microscopy, X-ray diffraction andRaman spectroscopy