THE DAMAGE MECHANISM OF SIC-MULLITE BRICKS IN CEMENT INDUSTRY

摘要

This essay will focus on SiC-mullite 1680 in the transitionzone of 5000 t/d large dry-process cement rotary kiln and exploreerosion mechanism by layers connected with Portland cementclink in the upper transitional zone. The brick(the thickness is220mm) is divided into four parts equally, XRD and SEM isemployed to analysis phases changes and relative variable inchemical composition of different depth of the SiC-mullite brick;;and reaction products between cement clinker and the brick. Theresults reveal that potassium contained in alkali salt reacted withcorundum and mullite phase to produce KAlSi2O6 and KAlO4 oflow melting point. Moreover, SiC contained in the reaction layerwas oxidized seriously, and the difference of thermal conductivityin different depth of the brick lead to the formation of distortionstrain. Therefore the impact of alkali salt and partly oxidation ofSiC are the main causes for damage of SiC-mullite brick.