The Study On The Mullite Castable Used In Injection Lance

By means of XRD analysis, SEM, EPMA, DSC-TG and thermodynamic calculation, three parts were studied as follows. In the first part the properties of mullite castable and the effects of andalusite aggregate were investigated. The effects of SiC powder on properties of mullite castable were investigated in the second part. In the third part the effects of Si powder on properties of mullite castable were investigated. The results show that:1. After andalusite aggregates were introduced to mullite castable, coefficient of thermal expansion and ratio of thermal expansion of samples were increasing. At the same time, MOR of samples decrease and thermal shock resistance was improved. The reason is that the cracks formed by differences of thermal expansion coefficient between andalusite aggregates and matrix in castable stop the propagating of cracks formed during thermal shock.2. The effects of SiC powder and SiC micro on properties of mullite castable were similar. MOR of samples dried and soaked at 800 C decrease and that of samples sintered at 1400 C were improved with increasing SiC content. Thermal shock resistance of samples sintered at 800 C and 1400 C were improved at first then decrease with increasing SiC content. For the castable with andalusite, MOR of samples dried and soaked at 800 C decreases and that of samples sintered at 1400 C was improved with increasing SiC content, and thermal shock resistance was improved with increasing SiC content.3 MOR of samples dried and soaked at 800 C change little and that of samples sintered at 1400 C was improved with increasing Si content. Thermal shock resistance of samples soaked at 800 C decreases with increasing Si content and that of samples sintered at 1400 C was very bad.