Stability of Refractory Castables to Steam-N2 and Steam-CO Atmospheres

摘要

The properties of three refractory castables, desig¬nated as High, Intermediate, and Low A2O3, were investi¬gated after the castables had been exposed to steam-N2 and steam-CO atmospheres at 199°C and 450 psi for 6, 12, and 18 days. Four general chemical reactions were identified. First, the residual unreacted calcium aluminate cement com¬pounds in the castables reacted with the steam to form ad¬ditional cementitous material. This reaction was consi¬dered primarily responsible for the observed increase in mechanical strength of the castables. Second, a portion of the cement bond in the castables was destroyed by the CO, CO2, and H2O in the test atmospheres, as evidenced by the reaction of CaO to form CaC03 and CaCHC02)2.