Jesper Stjernberg, Marta-Lena Antti, Lars-Olof Nordin, Magnus Odén
Online: Nov 5 2008 3:13PM
Degradation of bricks in an iron ore pellet producing kiln has been
investigated. Lab-scale tests of brick/slag interaction performed under
different temperatures, atmospheres, and alkali additions show that
addition of alkali dissolves the mullite in the brick and leads to
formation of the phase nepheline (Na2O·Al2O3·2SiO2).
At a high temperature, the grain boundary where nepheline is formed
disintegrates due to volume expansion. At increased temperature, the
nepheline transforms to an amorphous phase. Thus, a wear mechanism is
proposed in the kiln using these bricks that involves these chemical
reactions in combination with erosion by the continuously flowing slag.