Journal of the American Ceramic Society · 1971 · 14 citations · 3 references
Color development of shale and fireclay bricks fired and cooled in various atmospheres was evaluated. Iron oxide is the primary colorant in most brick clays; the key to color development and control flexibility is control of the oxidation state and physical or mineralogical state of the iron in the brick, e.g. whether iron is present in a glassy phase, as free oxides, or in a more complex crystalline phase. The influence of H 2 O vapor on black core elimination was studied. Increasing H 2 O vapor concentrations in oxidizing atmospheres greatly accelerate the elimination of carbon by the water‐gas reaction. The improved burnout depends on the type of carbon in the raw material, since carbon must be present above the temperature at which the water‐gas reaction becomes effective.
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