Study on a Self-Driven Mineral Carbonation Path in Solid Waste

Mineral carbonation technology is primarily categorized into direct and indirect approaches for the effective fixation of CO2. The direct approach involves gas–solid or liquid-phase reactions that bind CO2 directly to minerals. Nevertheless, this method is constrained by slow reaction rates and high costs. The indirect approach extracts calcium and magnesium ions from minerals for subsequent carbonation processing. However, it also encounters considerable cost and technical difficulties. Despite these limitations, mineral carbonation technology holds substantial potential for CO2 sequestration. To address the constraints of traditional methods, this paper innovatively proposes a self-driven mineral carbonation. By introduction of an internal carbon source, this technology simplifies the carbonation conditions, reduces energy consumption, improves economic viability, and enhances its potential for widespread application. In this study, the feasibility of employing an internal carbon source for carbonation was thoroughly investigated. The influence of key factors (the amount of carbon source, temperature, and time) on the compressive strength of steel slag after carbonation was also extensively analyzed. The test results demonstrate that the compressive strength of carbonated steel slag reaches as high as 34.02 MPa, which fully meets practical requirements and offers a promising solution for mineral carbonation. Furthermore, this paper proposes a novel concept of a coupled capture and carbonization process, aiming to enhance the integration of CCUS (carbon capture, utilization, and storage) processes to more effectively advance carbon reduction goals. This innovative approach not only offers a fresh perspective for future solid waste mineral carbonation endeavors but also brings forth new ideas for the global pursuit of carbon emission reduction.