Preparation Of Mullite Gel And Application In Corundum-Mullite Refractory

The Al2O3 sol was firstly synthesized via Sol-Gel process by using Al2(SO4)3·18H2O and (CH2)6N4 as starting materials, through which the mullite gel was prepared by adding the available SiO2 sol on market. DTA, TGA and XRD studies were carried to characterize on the prepared mullite gel. It is indicated that the gel starts to transforme into mullite at 1100℃and finishs at 1300℃.The mullite gel was used as binder for the corundum-mullite firebricks and brings forth the products high purity and outstanding high tempreture properties after being sintered at 1520℃.6wt% is determined as the suitable addition. It is shown that the densification, the strength of corundum-mullite firebricks and especially the thermal shock resistence can be improved by the mullite gel. The added gel can be transformed into spicule and pillar mullite in the matrix, which is the main reason for the improved strength and thermal shock resistence of the samples.