Exploring the potential of olivine-containing copper-nickel slag for carbon dioxide mineralization in cementitious materials

Water-quenched copper-nickel metallurgical slag, enriched with olivine minerals, exhibits promising potential for the production of CO₂ mineralization cementitious materials. In this work, we synthesized copper-nickel slag-based cementitious material (CNCM) by using different chemical activation methods to enhance its hydration reactivity and CO₂ mineralization capacity. Different water curing ages and carbonation conditions are explored with the examination of the mechanical properties and microstructure development of carbonated CNCM blocks. Meanwhile, thermogravimetry-differential scanning calorimetry and X-ray diffraction methods are used to evaluate the CO₂ adsorption amount and carbonation products of CNCM. Results show that the 3 d water-cured CNCM exhibited the highest CO₂ sequestration amount of 8.51 wt.% at 80 ℃ and 72 h while achieving a compressive strength of 39.07 MPa among the studied samples. This means that one ton of this CNCM can sequester 85.1 kg of CO₂ as well with high compressive strength. The addition of citric acid does not improve the strength development but is beneficial to increase the CO₂ diffusion and adsorption amount at the same carbonation condition. This work provided a possible solution for This work could be guidance for synthesizing CO₂ mineralization cementitious materials with large usage of metallurgical slags containing olivine minerals.