Secondary phases in natural magnesite sintered with addition of titania, ilmenite and zirconia

摘要

The detail microstructures of sintered naturalmagnesite with addition of titania, zirconia and ilmenitemineralisers were studied using scanning electron microscopy(SEM) with special emphasis on energy dispersive X-ray analyses(EDXA). The study was directed towards the determination ofsecondary phase composition in sintered magnesite with differentmineraliser addition. In order to evaluate the secondary phaseswith addition of transition metal oxides, keeping titania (TiO2) as areference mineraliser, a natural analog of titania containing ironi.e., llmenite (Fe2O3·TiO2) and pure Zirconia (ZrO2) were added tomagnesite which was then sintered up to 1700℃. The relativebehaviour of these pure and mixed oxide mineralisers during thesintering of magnesite has been evaluated with respect to theirmicrostructure and secondary phase composition The present papershowed that titania addition to natural magnesites resulted in theformtion of calcium titanate in the secondary phase upon sintering.Zirconia, on the other hand, did not show any reaction product inthe secondary phase. The addition of titania in the form of mixedoxide, ilmenite, also gave rise to calcium titanate formation,providing a similar microstructure, specially with reference tospatial distribution of phases in the secondary phase.