Fundamental investigations on the high temperature corrosion of ZrSiO4-containing andalusite refractories in cement kiln preheater

ZrSiO4-containing andalusite brick after service in cement kiln preheater was analysed by means of XRF, XRD and SEM/EDS techniques in order to determine the corrosion mechanism during 8-months industrial-scale corrosion test in high-alkaline environment at 1100 C. The detailed investigation of the wear mechanism through post-mortem studies of the ZrSiO4-containing andalusite brick showed that the K-aluminosilicate phases were formed along with a liquid phase as a consequence of reactions between potassium and andalusite. Ca-aluminosilicate and CaZrO3 phases were also formed. In this paper, a new model of the refractory corrosion was proposed. In modelling the corrosion of zircon-containing andalusite refractory material, ZrSiO4 and Al2SiO5 single grains were used to represent the refractory, so that in all cases the isothermal sections of CaO-Al2O3-SiO2, K2O-Al2O3-SiO2 and CaO-ZrO2-SiO2 systems at 1100 degrees C were used to identify the equilibrium phases and also to explain the mechanism of corrosion. (C) 2015 Elsevier Ltd. All rights reserved.