Efficient AlN decomposition and Al species transformation in secondary aluminum dross through co-sintering with waste sodium acetate

Secondary aluminum dross (SAD) is a rich source of recyclable aluminum but poses considerable risk due to its high AlN content. Therefore, thoroughly removing AlN is essential, but intricate aluminum components and expensive additives pose challenges to the process. In this study, waste sodium acetate is proposed as an environmentally friendly additive for completely removing AlN and enhancing the extraction of aluminum from SAD. Through the exothermic decomposition of NaAc, reactions can occur at 850°C. AlN removal efficiency reached 93.19% after sintering, whereas Al leaching efficiency in the subsequent leaching process reached 90.49%, which were 37.86% and 375.26% higher than the removal efficiency of the control, respectively. These favorable results were attributed to the comprehensive transformation of aluminum species. The formation of soluble phase Na_1.95Al_1.95Si_0.05O₄ occurred during the destruction of the Al₂O₃ layer surrounding AlN and the transformation of other aluminum components. AlN decomposed upon contact with NaAc. Therefore, this study utilizes the decomposition properties of NaAc to provide an efficient and environmentally friendly route for removing AlN and extracting Al from SAD.