Evaluating Recycling Potential of Waste Alumina Powder for Ceramics Production Using Response Surface Methodology

Abstract The generated process losses such as broken ware from shaping, if not recycled internally, are considered as waste. Furthermore, the collected process losses are provided to external recycling companies or waste disposal facilities. This study investigated the recycling potential of waste alumina powder, which was accumulated during industrial machining of the ceramic green body. The samples containing up to 20 dwb. % (dwb – weight amounts based on dry matter) of powdered waste alumina were prepared by slip casting method and conventionally sintered at various sintering conditions according to Box-Behnken design. Sintered samples were characterized for density, microstructure, hardness, and indentation fracture toughness and compared with samples made of pure commercial alumina. The study shows that the addition of waste alumina up to 20 dwb. % sintered at higher sintering temperature with dwell time 1-3 h did not negatively affect the hardness, nor the indentation fracture toughness of the sintered samples. The enabled recycling potential of waste alumina powder can have direct positive environmental impact, although economic benefits cannot be ignored.