ZnO and MgO as inducers of spinel-like phase formation on alumina-based castables

Environmental issues regarding Cr6+ formation lead to replacing chrome-containing refractories with greener alternatives. MgO-containing compositions have been extensively investigated for this purpose, however, few studies evaluated the likelihood of using other chemical elements as inducers spinel-like phase in refractory castables. In study, addition zincite alumina-based castables was and compared its MgO-counterpart. In-situ elastic modulus, assisted sinterability differential scanning calorimetry pointed out that gahnite (ZnAl2O4) took place at lower temperatures (∼ 1100 °C) than MgAl2O4 1300 °C). On one hand, feature induces anticipated strengthening Zn-containing compositions, giving rise possibility firing these temperatures. other, faster kinetics led a significant Kirkendall effect, changing morphology pores created during sintering, which became preferentially located interface alumina aggregates, negatively affecting some mechanical properties castable.