Decarbonizing the aluminium industry: A comprehensive review of pathways and process integration perspectives

Aluminium is recognized as an essential material for the global energy transition. However, its production is extremely energy-intensive and largely dependent on fossil fuels. The aluminium industry emits more than 1.11 Gt CO 2 -eq annually. Multiple obstacles persist in the face of decarbonizing such a heavy industry, including a shortage of alternative technologies for high-temperature furnace applications, unavailability of renewable electricity sources sufficient to supply continuous power loads, and inefficiencies of material recycling pathways. This review focuses on critically evaluating these challenges and defining methods to overcome them. A decarbonization framework is proposed for the aluminium industry through four interconnected layers: process integration, energy and exergy efficiency, techno-economics, and life cycle assessment (LCA). Twenty decarbonization metrics are computed across the four layers of this framework. The most relevant of which are process energy load, renewability index, carbon balance, total cost, and technology readiness level. Key mitigation strategies such as carbon capture, biomass use, and grid decarbonization, are found to collectively drive emission reductions in the aluminium sector. This review addresses key knowledge gaps in the literature and offers a structured framework to support strategic decision-making across the aluminium value chain. • Comprehensive review of aluminium industry pathways to net-zero. • Main decarbonization challenge is energy intensity of primary aluminium production. • Bottleneck for decarbonizing secondary aluminium is high temperature melting. • Pinch analysis methods must be adapted for analysis of solid semi-batch systems. • Life cycle assessment is critical for a multi-criterion decarbonization approach.