Improvement of Mullite and Magnesia-Based Refractory Castables Through Addition of Nano-Spinel Powder



Two different commercial refractory castables based on mullite or magnesia aggregates have been improved through addition of 0–25 wt.% nano-magnesium aluminate spinel (MA) powder. Physico-mechanical and refractory properties were tested at different firing temperatures. The phase composition, thermal analysis, and microstructure of these refractory castables were detected using X-ray diffraction (XRD), differential thermal analysis (DTA), as well as scanning electron microscope (SEM) attached with energy dispersive X-ray unit, respectively. The castable sample mix containing 10 wt.% nano-MA spinel powder was chosen as an optimum composition according to its good sintering, mechanical as well as refractory properties.