Environmental and economic life cycle assessment of aluminum-silicon alloys production: a case study in China

A coupled life cycle costing and life cycle assessment was carried out to estimate the economic and environmental impact of silicon-aluminum alloy production. The results showed that the aluminum alloy made from secondary aluminum accounted for 70%–95% of the environmental benefits in most categories, except in the land occupation and economic categories, compared with the aluminum alloy made from primary aluminum. These findings could be attributed to the decrease in energy and raw material consumption (i.e., electricity, sodium hydroxide, petroleum coke, and charcoal consumption) and the relatively high cost of secondary aluminum scrap. Optimizing raw material and electricity consumption efficiency, decreasing the transport distance from raw material (e.g., bauxite and old aluminum scrap) buyers to suppliers, and changing the end-life treatment of red mud from landfill to road building material production are key factors in reducing the overall environmental and economic impact.