High-Gravity Carbonation Process Using Rotating Packed Bed for Carbon Capture and Waste Utilization in Steelmaking Industry

In this study, an integrated approach to waste-to-resource technology was developed for CO₂ capture, wastewater neutralization and product utilization in a high-gravity carbonation process, i.e., rotating packed bed (RPB).  Steelmaking slags including electric arc furnace slag (EAFS) and basic oxygen furnace slag (BOFS) were gathered for performance evaluation operated under various levels of particle size of slag, reaction temperature, rotation speed, and liquid-to-solid ratio.  According to the observations of TGA, XRD and SEM-EDX, the alkaline wastes were found to be successfully carbonated with CO₂ in an RPB, where calcite (CaCO₃) was identified as the main product.  Furthermore, blended cements containing 10% and 20% replacements of ordinary Portland cement (OPC) with carbonated slag were tested for strength development and autoclave soundness.  For instance, compressive strengths of mortars cast into 50 mm × 50 mm × 50 mm molds were tested at 3, 7, and 28 days according to ATSM C109.  The results indicated that the cementitious activity and strength contribution of carbonated slag were suitable to serve as supplementary cementitious Materials for cement-based materials, even up to 20% replacement.