Synthesis of galaxite by sintering at various temperatures and atmospheres

Galaxite has broad application prospects in the field of cement rotary kiln burning zones owing to its excellent properties (high melting point and corrosion resistance). In this study, MnO and alpha-Al2O3 powders were used as raw materials to synthesize galaxite in air, coke bed, or nitrogen at 1500-1600 degrees C. Their phase compositions and microstructure changes were investigated by XRD and SEM-EDS. The results show that MnII(Al, MnIII)2O4 composite spinel were formed in the air at 1500-1600 degrees C and increased with increasing temperature, whereas only MnAl2O4 was formed in the coke bed and nitrogen at 1550 degrees C. Therefore, the specimens treated at 1600 degrees C in air exhibited a high density of 3.88 g/cm3, which was similar to those of the specimens sintered in the coke bed and nitrogen at 1550 degrees C, demonstrating good sintering properties. Furthermore, the number and size of pores gradually decreased, and the bulk density increased as the temperature increased from 1500 degrees C to 1600 degrees C in the air.