Carbon sequestration and life cycle assessment of an industrial waste-derived carbon sink binder under saline water utilization

Abstract

The development of low-carbon construction materials is essential to meeting global climate targets. This study presents a carbon-negative binder synthesized primarily from iron-rich industrial byproducts (mill scale), supplemented with fly ash, metakaolin, and limestone. Oxalic acid enhances iron dissolution and promotes stable carbonate formation during CO<inf>2</inf> curing. Strength development occurs through direct CO<inf>2</inf> mineralization, with carbonation curing conducted at 0, 1.5, and 3 bar using both normal and saline water. Specimens cured at 3 bar with saline water achieved compressive strengths exceeding 60 MPa and carbon sequestration rates up to 1.03% per day. Carbonation depth followed a square-root time relationship, with enhanced propagation under high-pressure saline conditions. Microstructural analyses (XRD, TGA–DTG, FTIR, FESEM) confirmed the formation of siderite, lepidocrocite, nesquehonite, and calcite within a dense matrix. Life Cycle Assessment indicated approximately 85% lower fossil-based global warming potential and over 80% reductions in water consumption compared to Ordinary Portland Cement, demonstrating a potable-water-free, resource-efficient binder suitable for circular and climate-resilient infrastructure. © 2025 Informa UK Limited, trading as Taylor & Francis Group.