Strategic Retrofits Resolve China’s Aluminum Trilemma: Integrated LCSA Modeling Reconciles Emissions, Costs, and Social Risks

As the world’s largest aluminum producer, China faces urgent sustainability challenges due to resource scarcity and carbon-intensive practices. This study employs an integrated life cycle sustainability assessment (LCSA)─spanning environmental (LCA), economic (LCC), and social (SLCA) dimensions─to evaluate primary and secondary aluminum production. Results reveal that integrated smelting refining (ISR) leads environmentally, whereas separated smelting refining (SSR) reduces costs by 18–22%. Both pathways reduce social labor risks by 35–50% according to SLCA. Applying a novel integrated LCSA framework to resolve these trade-offs, our initial assessment favored ISR (LCSA score = 0.54) over SSR (0.55). However, after retrofitting SSR with enhanced scrap utilization, biomass energy substitution, and labor optimization, its LCSA score dramatically improved to 0.49, surpassing that of the ISR (0.50). This retrofitted approach achieves 8–10% of the sustainability benefits at only 30–40% of the cost of building new facilities, demonstrating superior efficiency through retrofitting compared to full technology transition. Policy recommendations include incentivizing SSR retrofits, establishing regional circular hubs, incorporating social criteria into green certifications, and enhancing scrap traceability. This strategy supports decarbonization, resource efficiency, and social equity without sacrificing economic growth, providing a practical toolkit for enhancing the sustainability of the global aluminum industry.