Impacts of aluminum production: A cradle to gate investigation using life-cycle assessment

Abstract

In this study, a life-cycle assessment from the aluminum production processes is carried out by considering four major steps of aluminum production - bauxite mining from the ore, alumina production, smelting, and the ingot casting process of aluminum. The study considered the cradle to gate system to analyze and quantify the environmental impacts during aluminum production process from raw materials to the final finished product. The production input and output datasets are taken from the databases and eGrid reports and the analysis is carried out utilizing three different methods, namely the International Life-cycle Reference Data System (ILCD) method, the Tool for Reduction and Assessment of Chemicals and Other Environmental Impacts (TRACI) method, and the Cumulative Energy Demand (CED) method. The results show electricity consumption in aluminum smelting causes noteworthy environmental burdens among all the processes or materials involved. Residual fuel oil, diesel, and natural gas consumption during the alumina production is also a major contributor to environmental impacts. Sensitivity analysis is conducted to justify the variation of environmental impacts in proportion with the modes of electricity generation from different sources to be used for aluminum smelting. Further sensitivity analysis is carried out among the quantity of the fossil fuel used based on their sources for process heat generation during alumina production. According to the sensitivity analysis results, renewable energy integration or reducing the consumption of fossil fuels would be the promising alternative to reduce the environmental burdens associated with aluminum production.

Keywords: Aluminum; Bauxite; Life-cycle assessment; Refining; Smelting.