Influence of time and temperature on ageing and phases synthesis in the MgO–SiO2–H2O system

The behaviour of the mixture of MgO and SiO2 with water was studied and analyzed by DTA–TGA–EGA and XRD after ageing for 1, 3, 10, 30 and 180 days at 20 °C. The samples also were aged at 30 °C and 40 °C for 1 and 3 days. Additionally, after 180 days the samples were heated in 500 °C, 700 °C and 900 °C for 24 h. The paste was composed of magnesium oxide and microsilica in 1:1 molar ratio and water in addition of 50% wt. of oxides. The DTA–TGA–EGA curves in the temperature range 20–950 °C were analyzed. The aim of this work was to study the reaction and phase composition in the MgO–SiO2–H2O phase system. This system has wide applications in refractory materials, especially in basic castables. The compounds of this system may constitute an innovative bonding phase in a new generation basic castables.