Analysis of Variables in Accelerated Carbonation Environment for the Processing of Electric Arc Furnace Slag Aggregate

Emission reduction in the steel industry has become a challenge due to its high environmental impact, being responsible for 7% of anthropogenic emissions. Several strategies have emerged to mitigate its carbon footprint; among them, carbon capture and storage (CCS) has become a promising long-term alternative. In this work, two low-energy mineral carbonation methods—aqueous and semi-dry—were considered for the processing of a commercial slag derived from electric arc furnace (EAF) steelmaking. These methods were selected for their lower energy and water requirements, as they operate at atmospheric pressure, moderate temperatures, and involve minimal use of chemical additives. Variables such as temperature, time, and the use of sodium carbonate were analysed. Aqueous carbonation favoured a higher carbonate precipitation compared to semi-dry carbonation. However, this process also led to an increase in microcracks on the surface. With respect to the theoretical sequestration rate, carbon dioxide fixation was relatively low, reaching values close to 3%. Nevertheless, when evaluating the overall impact of carbonation on the final material properties, the results suggest that low-consumption mineral carbonation, particularly under simplified operational conditions, is a promising strategy for industrial application. In addition to contributing to CO2 sequestration, this process improves physical properties, which reinforces its potential in carbon capture and storage strategies.