<p>The utilization of iron- and steel-derived waste as a primary binding material in cement-free binder systems remains limited, with most existing studies focusing on its use as an aggregate or partial cement replacement. In response to this research gap, this study presents a composite binder material developed primarily from iron and steel industry waste, aimed at reducing CO₂ emissions associated with conventional cement production while enabling carbon sequestration through controlled CO₂ curing. The research details the synthesis of this material through precise proportioning, material selection, and optimization of dosages and binder ratios. It also provides comprehensive methodologies for mixing, casting, and curing to ensure clarity and replicability in future work. Composed of 60% waste iron sources, 20% fly ash, 10% limestone, and 10% metakaolin, the binder achieves strengths up to 45 MPa, outperforming most building bricks and blocks. Optimized mixing and casting ensure uniform density and strength, while controlled CO₂ curing enhances strength and carbon sequestration, capturing approximately 10% of its initial dry mass as CO₂. With a flexural strength of 5 MPa and compressive strength of up to 35 MPa in saline water, the binder shows potential for structural applications and use in saline environments. Microstructural analysis was conducted to validate the results and identify the compounds influencing the material’s strength. By incorporating 80% of its composition with waste materials, this binder supports sustainable waste management, surpasses conventional materials in strength, and reduces reliance on traditional cement.</p>