Comparative Life Cycle Assessment of Management and Valorization Practices for Bauxite Residue

The management of bauxite residue (BR) generated during alumina production, is techno-economically challenging due to its colloidal slurry form, high alkalinity, and elevated concentrations of heavy metals and radionuclides. For every tonne of aluminum produced, 2–3 tonnes of BR are generated, leading to an annual global accumulation of approximately 180 million tonnes. At present, dry disposal (“dry stacking”) has become the most widely adopted management practice, although wet disposal of slurry remains in use in several regions. In this context, the present study assesses the environmental impact and the associated energy consumption of BR management following three different management and valorization practices: the wet disposal of the residue (baseline scenario), the dry disposal followed by the partial use of the dried BR in cement clinkering (current practice of the Greek aluminum industry) and the dry disposal followed by the partial use of the dried BR in a geopolymerization process. Results show that impact categories such as acidification (AC), freshwater eutrophication (FC), ozone depletion (OD), and photochemical ozone formation (POF) decrease by 21.6–77.7% under drying/valorization compared with the baseline. Dry disposal/geopolymer manufacturing presents the lowest possible environmental impact. However, the decrease of the global warming (GW) (by 12.8%), is relatively limited, while CED increases by 54.2% due to geopolymerization. Given the limited number of LCA studies available on bauxite residue management, this study explores key environmental challenges posed by current practices and identifies opportunities for improving sustainability and resource efficiency within the aluminum industry.