Deployment of Accelerated Carbonation Using Alkaline Solid Wastes for Carbon Mineralization and Utilization Toward a Circular Economy

This study suggests that the waste-to-resource supply chain can offer an approach to address simultaneously the issues of waste management and CO2 emissions toward a circular economy. Alkaline solid wastes can be used to mineralize CO2 through an accelerated carbonation reaction, especially if the wastes are generated near the point source of CO2, to achieve environmental and economic benefits. To enhance the performance of accelerated carbonation, a high-gravity carbonation process using a rotating packed bed reactor was developed and deployed. Due to additional energy consumption in high-gravity carbonation, the environmental benefits and economic costs should be critically assessed from a life-cycle perspective. In this study, the resource potential of alkaline solid wastes in Taiwan was first determined for CO2 mineralization and utilization using the high-gravity carbonation process. Then, the performances of the process from engineering, environmental, and economic perspectives were evaluated and exemplified by a steelmaking plant. The results indicated that, with a CO2 removal ratio of 97–98%, the energy consumption of the high-gravity carbonation was estimated to be ∼345 kWh/t-CO2. From the perspective of environmental benefits, CO2 emission from the cement industry could be indirectly avoided by roughly one t-CO2-eq/t-slag due to the utilization of carbonated products.