Preparation and characterization of barium containing refractory materials

Two grades of barium-containing refractory grains were processed from low and high purity materials by sintering methods after firing up to 1700°C. The first one was prepared from highly pure Al2O3 and BaSO4, while the second one was prepared from raw Egyptian barite and Chinese bauxite. The densification parameters in terms of bulk density and apparent porosity were determined using the water displacement method. XRD was used for qualitative determination of phase composition, while SEM attached with an EDS unit was applied to study microstructure and microanalysis of the formed phases. The results reveal that grains processed from pure materials show BA6 as a major phase with lower densification and open pores as compared with those prepared from commercial materials which exhibit higher densification and direct-bonded celsian/celsian and celsian/corundum phases with minor closed pores. The presence of higher amount of fluxing oxides, especially SiO2 and Fe2O3 in the latter one has contributed in lowering its densification temperature and refractoriness as well as increasing its cold crushing strength.