Castable systems designed with powders reclaimed from dismantled steel induction furnace refractory linings

Despite environmental pressures and intrinsic recycling potential, spent refractories waste is generally considered an economically unattractive waste stream. This work proposes an upgraded view of the debris recovered from dismantled spinel-bonded high-alumina linings of steel induction furnaces, demonstrating that it can be reused in the form of vibratable and self-flowing castable systems. The recovered material retains the microstructural distribution of in situ spinel formation without the corresponding disruptive expansion, mirroring the use of pre-formed spinel without the onus of a pre-firing. The mechanical performance after firing was found to be always best for the self-flowing system, which is also less affected by changes in added-water content. There is potential for large usages of cleaned waste (50-60 wt%), which helps reducing the supply risk for major refractory primary raw materials as well as landfilling costs.