An LCA study of a primary aluminum supply chain

The production of aluminum billets—starting from the conversion of bauxite to alumina, the processing of alumina to aluminum, and the final cast product—is studied using a Life Cycle Assessment (LCA) approach. The aluminum supply chain consists of a refinery, a smelter, and a casting plant. In the LCA model, the environmental loads of four different case scenarios were investigated. The scenarios included various approaches employed for improving the environmental performance of the system for the production of 1 ton of aluminum metal. The final impact assessment results for the overall environmental loads of the supply chain showed cumulative decreases of 2.2% and 3.8% for Scenarios 2 and 3, respectively. In Scenario 2, scrap metal was reduced from the casting plant. For Scenario 3, the reduction of scrap metal from casting was accompanied by improvements of both energy efficiency and reject rates at the smelter. A significant cumulative decrease of 32.8% was obtained in Scenario 4, which was mainly due to the reduction of red mud from the refinery by about 50%.