Action Mechanism of β-Si3N4 in Bauxite Sintering

In this paper, we added silicon nitride in the samples of common bauxite and the bauxite with high potassium and sodium oxide content, treated them at the high temperature of 1,400°Cand 1,500°C, and then conducted analysis with XRD, SEM and EDS. The results are as follows: After adding β-Si3N4 in sintered bauxite, the partial pressure of oxygen in the composite materials will be reduced, the decomposition and volatilization of compounds with high partial pressure of oxygen (such as potassium oxide and sodium oxide) will be promoted, the content of these compounds in the bauxite will be lowered, and the hazards of the compounds with low melting point will be weakened; meanwhile, with the reduction of potassium, sodium and iron oxide, the lattice of alumina will be activated, the β-Sialon phase will be easily formed and the high temperature properties of sintered bauxite materials will be strengthened.