Related to the recent extension of the service life of coke ovens, the refractory damage and defects have increased and become highly visible. To cope with the problems, a special silica brick was developed that is most suitable for brick replacement repairs in the hot condition. The characteristics and field service results of this special silica brick are summarized as follows: The newly developed brick has a thermal expansion coefficient, lower than ordinary silica brick, and superior thermal spalling resistance, whereby there is no crack initiation due to rapid heating from room temperature to 200 to 500 deg C. The newly developed brick has excellent volume stability in the hot condition (> 600 deg C), similar to ordinary silica brick. The newly developed brick can be used for a wide variety of brick replacement repairs in the hot condition, from a small section of the coking chamber wall and/or the combustion chamber in the front section of an oven to a larger section extending from the front to the middle part of the chamber wall in a coke oven. As one example, the results of investigation of used special silica brick after two years of service in a coking chamber wall showed excellent performance, with no crack initiation, no deteriorated layer, and no other damage. After service, the special silica brick had higher cold crushing strength due to effect of thermal hysteresis, and the tridymite content increased. As a result, it was confirmed that during service, the newly developed silica brick proceeds to approach the properties and mineral composition of ordinary silica brick.
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