铬盐焙烧旋窑烧成带衬砖损毁机制初探

Preliminary investigation on damage mechanism of lining brick at burning zone of chromic salt-roasting rotary kiln

采用XRF、XRD、SEM等分析手段对铬盐焙烧旋窑烧成带衬砖的化学组成和微观结构进行了分层分析,探究了衬砖的损毁机制。结果表明,导致铬盐焙烧旋窑烧成带衬砖损毁的原因是:1)衬砖中A l2O3量的降低和Na2O等杂质成分的渗入,衬砖在高温下生成的液相量增多,衬砖的耐火性能和高温力学性能降低。2)碱性氧化物和硫化物渗入衬砖中,与原砖中的莫来石反应生成方钠石族物相,莫来石结构被破坏。3)烧成带常出现结圈现象,打圈机的机械冲击对衬砖具有破坏作用。

The chemical compositions and microstructure of individual layer of the lining brick used at the burning zone of chromic salt-roasting rotary kiln were analyzed by XRF,XRD,and SEM. The damage mechanism of kiln lining brick was also investigated. The result indicates that the damage causes of lining brick are as follows：（ ! ）with the reduction of alumina and infiltration of impurities,the increasing liquid forms in lining brick at high temperatures, so refractoriness and hot mechanical behavior decline; （2）alkaline oxides and sulfides infiltrate into the lining brick and react with mullite in the original brick forming sodalite phases and damaging the structure of mullite; （3）ringing phenomenon often occurs at the burning zone in the kiln,and the mechanical shock of ring-cleaning machine also has destructive action to the lining brick.