BURNED MAGNESIA-CHROME BRICK

PROBLEM TO BE SOLVED: To improve wear resistance, namely, high-temp. strength of the brick by adding a specified amount of fine-powdery ZrO2 having a specified particle size to semi-rebonded magnesia-chrome brick contg. a specified amount of electrofused magnesia-chrome clinker. SOLUTION: This magnesia-chrome brick is produced by adding 1 to 5 wt.% of fine-powdery ZrO2 having a =60 wt.% electrofused magnesia-chrome clinker. At the time of using the brick thus produced, for the lining of a smelting furnace, the added ZrO2 , together with CaO in slag, which is liable to disintegrate the structure of the brick, forms CaO.ZrO2 to stabilize the CaO and to inhibit the CaO from infiltrating into the brick. On the other hand, when an excessive amount of the ZrO2 is added, the added ZrO2 , together with another component SiO2 in the brick, forms a low-melting compound to soften the brick. The smaller the particle size of the ZrO2 is, with the smaller amount of the ZrO2 , a sufficient effect of the ZrO2 addition can be obtained. Thus, a strong bonding between the ZrO2 and CaO can be effected and also, reactivity of the ZrO2 to the SiO2 can be inhibited.