The high-gravity carbonation process for CO2 mineralization and product utilization as a green cement was evaluated using field operation data from the steelmaking industry. The effect of key operating factors, including rotation speed, liquid-to-solid ratio, gas flow rate, and slurry flow rate, on CO2 removal efficiency was studied. The results indicated that a maximal CO2 removal of 97.3% was achieved using basic oxygen furnace slag at a gas-to-slurry ratio of 40, with a capture capacity of 165 kg of CO2 per day. In addition, the product with different carbonation conversions (i.e., 0%, 17%, and 48%) was used as supplementary cementitious materials in blended cement at various substitution ratios (i.e., 0%, 10%, and 20%). The performance of the blended cement mortar, including physicochemical properties, morphology, mineralogy, compressive strength, and autoclave soundness, was evaluated. The results indicated that the mortar with a high carbonation conversion of slag exhibited a higher mechanical strength in the early stage than pure portland cement mortar, suggesting its suitability for use as a high early strength cement. It also possessed superior soundness compared to the mortar using fresh slag. Furthermore, the optimal operating conditions of the high-gravity carbonation were determined by response surface models for maximizing CO2 removal efficiency and minimizing energy consumption.

An integrated reclaimed process of refining slag with calcium-containing wastewater for CO2 mineralization and utilization by using a high-gravity carbonation process was proposed in this study. The effect of various liquid agents on calcium ion leaching behavior from the refining slag was determined and the mass-loss method was used to evaluate the leaching kinetics. The influence of different high gravity factor and liquid-to-solid ratio on carbonation conversions were investigated and the reaction kinetics were identified via surface coverage model. The efficacy of refining slag utilized as supplementary cementitious materials including workability and mechanical strength was assessed. The morphological, mineralogical, and thermal analyses were carried out and the results revealed the presence of calcite to support the carbonation theory. The results of maximal CO2 capture capacity of 0.183 g CO2 per g slag and performance of carbonated slag utilization with 5% and 10% substitution ratio confirmed the feasibility of the integrated reclaimed process.