Stability of Refractory Castables in Steam-N₂ and Steam-CO Atmospheres at 199 Degree C

The properties of a high, intermediate and low Al2O3 refractory castable were investigated after exposure to steam--N2 and steam--CO atmospheres at 465 psia and 199/sup 0/C for 6, 12 and 18 days. Chemical reactions consisted of (1) the hydration of residual unreacted calcium aluminate cement to form additional cementitious phases, (2) the leaching of CaO from the castable and its reaction to form CaCO3 and calcium formate, (3) the hydration of alumina to form boehmite and (4) the dissolution of SiO2 by steam. The properties of the intermediate Al2O3 castable were least affected by the exposure conditions