Utilization of accelerated carbonation to enhance the application of steel slag: a review

Accelerated carbonation can promote the application of steel slag in construction materials. This method can not only resolve the fatal volume expansion of steel slag, but also sequestrate CO2. The carbonation thermodynamics, carbonation degree, carbonation methods and influencing factors of steel slag were reviewed. The theoretical CO2 uptake of steel slag is between 25% to 50%. However, the actual CO2 uptake distribution curve obeys normal distribution with a median value of 15%, which affected by carbonation methods, different influencing factors such as curing temperature, CO2 concentration and pressure, particle size of steel slag, liquid to solid ratio, and extraction agents. The improvement mechanism of accelerated carbonation on mechanical properties and stability of steel slag-based building materials was analyzed. Besides, different accelerated carbonated steel slag-based products with enhanced properties were summarized. Finally, some valuable suggestions concerning accelerated carbonation of steel slag were presented for further research and industrial application.