Understanding bauxite residue: a review of its historical evolution and potential in sustainable construction

Bauxite residue (BR) also known as bauxite tailings, an abundant by-product of the Bayer process for alumina production, presents a global environmental challenge with over 4 Gt currently stored in landfills. This review covers the historical evolution of BR generation, noting that bauxite residue generation was recognized as an environmental issue around 1980, highlighting the relatively recent emergence of this concern. It provides a detailed overview and comparison of BR utilization pathways as a supplementary cementitious material (SCM). While raw BR incorporation is limited (up to 5%), advanced processing techniques enable significantly higher substitution levels while meeting standard strength classes. The review discusses the potential of these methods to enhance mortar properties and promote circularity in construction, while also considering radiological implications, environmental safety, and economic factors. Key research gaps are identified, including the need for a comprehensive BR composition database, detailed radiological and leaching assessments, to guide future development and facilitate the large-scale, safe utilization of BR.