Magnesium refractory brick is mainly used in the lower transition zone, the fired zone and the hot end of the upper transition zone. The main varieties are magnesia-iron spinel bricks, magnesia-aluminum spinel bricks, magnesia-iron-aluminum spinel bricks, dolomite bricks and less commonly used magnesia-manganese spinel bricks, magnesia-zirconium spinel bricks, and Directly combined with magnesia-chrome bricks, etc., which have withdrawn from the cement market due to environmental problems.

Damage modes of magnesia refractory brick during co-processing in cement kilns

The damage of magnesium refractory brick is more complicated. From the experience of use, it is mainly divided into the damage caused by construction, and the damage caused by the interaction between the refractory brick and the working medium under the working conditions.

 

The damage of magnesium refractory brick caused by construction quality is mainly reflected in the additional mechanical stress on the lining bricks during working conditions, and the erosion of harmful components caused by co-processing aggravates this damage. There are three main situations. A common type of peeling groove with a locking brick area, the locking seam steel plate in the groove can be clearly seen. It is also common that the two ends are peeled off and the middle bulge is damaged, which is shaped like a bishop's hat, so it is vividly called "bishop's hat". The main reason is that the axial expansion of the kiln is not enough, and the extrusion causes the brick feet to fall. The last uncommon occurrence is damage to the lining bricks in contact with the retaining brick ring. The main reason is that the expansion joints at the first ring of bricks are unreasonably left during construction, or the mechanical strength of the lining bricks is not enough to withstand the downward movement of the lining bricks. The force causes the corners to crack. Others are basically rare due to structural problems of the block ring.