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Stability of refractory castables to steam-N/sub 2/ and steam-CO atmospheres

Technical Report ·
DOI:https://doi.org/10.2172/7311397· OSTI ID:7311397
The properties of three refractory castables, designated as high, intermediate, and low Al/sub 2/O/sub 3/, were investigated after the castables had been exposed to steam-N/sub 2/ and steam-CO atmospheres at 199/sup 0/C and 450 psi for 6, 12, and 18 days. Four general chemical reactions were identified. First, the residual unreacted calcium aluminate cement compounds in the castables reacted with the steam to form additional cementitous material. This reaction was considered 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, CO/sub 2/, and H/sub 2/O in the test atmospheres, as evidenced by the reaction of CaO to form CaCO/sub 3/ and Ca(HCO/sub 2/)/sub 2/. Third, the free Al/sub 2/O/sub 3/ in the castables hydrated to form boehmite. A volume expansion accompanied this reaction. Fourth, a portion of the free SiO/sub 2/ was removed from the SiO/sub 2/-containing castables by reacting with the steam.
Research Organization:
Los Alamos Scientific Lab., NM (USA)
DOE Contract Number:
W-7405-ENG-36
OSTI ID:
7311397
Report Number(s):
LA-6508-T
Country of Publication:
United States
Language:
English