Effect of sintering conditions on the stability of β-2CaO·SiO2 in high sodium carbonate solution

Abstract

In the lime sintering method, adding suitable amounts of Na2O can improve the alumina leaching ratio effectively, and reduce the sintering temperature. Meanwhile, the formation of β-2CaO·SiO2 will lead to a “secondary reaction”. The effect of sintering temperature and holding time on the stability of β-2CaO·SiO2 was studied by simulated dissolution experiments and XRD. The results show that the decomposition ratio of β-2CaO·SiO2 increased with increasing sintering temperature. Therefore, the stability reduced continuously. The decomposition ratio of β-2CaO·SiO2 was 13.98% when the sintering temperature was 1350 °C, but it increased to 16.54% when the sintering temperature was increased to 1450 °C. The decomposition ratio of β-2CaO·SiO2 increased first and then decreased with increasing holding time. When the holding time was 30 min, the decompositions ratio of β-2CaO·SiO2 was 12.04%, but increased to 16.31% when the holding time was extended to 60 min.