In order to improve the thermal spalling resistance of carbonaceous material-containing basic brick for the slide valve plate of facilities for the steel continuous casting process, spinel addition was investigated. Spinel is a favorable material in terms of thermal spalling resistance since it exhibits lower thermal expansion than MgO. However, corrosion resistance is inferior to MgO since the reactivity of spinel is higher than MgO. Thus, the grain size and fraction of spinel were optimized by laboratory experiment. In the series of experiments, a corrosion experiment and thermal spalling experiment were carried out. As a result, it was verified that utilization of coarse grain spinel is effective for minimizing corrosion resistance deterioration. This is attributable to lower surface area of spinel. On the other hand, no significant influence of spinel grain size on thermal spalling resistance was detected. Hence, thermal spalling resistance is considered to be governed by overall physical properties. Therefore, it was assumed that containing adequate amount of coarse spinel is desirable. The assumption was validated by numbers of commercial applications.
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