Efficient utilisation of spent pot lining, aluminium dross and red mud as supplementary cementing materials: a comprehensive review

Ordinary Portland cement (OPC) production releases nearly one ton of CO₂ per ton of cement produced, accounting for about 7% of global greenhouse gas (GHG) emissions and consuming vast natural resources. To address these environmental concerns, demand for sustainable construction materials has intensified, leading to research into industrial by-products as potential supplementary cementitious materials (SCMs). This review investigates the potential use of spent pot lining (SPL) generated at a rate of 20–25 kg per ton of primary aluminium, red mud (RM) produced at approximately 1.5 tons per ton of primary alumina, and aluminium dross (AD) formed at rate of 300–600 kg per ton of aluminium produced as SCMs in sustainable construction. It analyses their chemical and mineralogical properties, pozzolanic activity, and associated environmental and health risks to assess the feasibility of utilising SPL, RM and AD as SCMs. Treatment methods such as hydrometallurgical, pyrometallurgical and mechanical processes are examined to reduce toxicity and enhance material reactivity. The review highlights past research findings, discuss current challenges, such as standardisation and long-term performance, and identifies key areas for future study to support the safe and effective use of SPL, RM and AD in concrete production.