Waste-to-energy facilities are a way to manage municipal waste. Refractories used in the combustion chamber are exposed to a severe environment with high temperature (Tflue-gas ≈ 1200 °C) and corrosive species. To understand the damage mechanism of refractory material, a post-mortem analysis was conducted. Observations show an important loss of matter on the hot face of refractory tiles and the presence of large cavities on the corroded surface. Results highlight that the refractory matrix is the weakest point of the material. In contact with slag deposit and corrosive gases, the refractory bonding phase is dissolved and small SiC grains are oxidized. The wear mechanism also illustrates the importance of the porosity of SiC refractories. A numerical model of the shaping of SiC refractory tiles was studied to get density distribution in the tiles and some suggestions for improving their manufacturing are proposed.