Enhancing effect of β-cyclodextrin on carbonation properties of steel slag

Abstract

In order to improve the carbonation properties of steel slag, the carbonation reaction process of steel slag and the formation of carbonation products were regulated by the interaction between multiple hydroxyl groups within β-cyclodextrin (β-CD) molecule and calcium ions leached from steel slag. Through a meticulous experimental design, varying contents of β-CD, from 0.0 % to 5.0 %, were mixed with steel slag to investigate their impact on carbonation kinetics, mechanical strength, and microstructural evolution. The results indicate that β-CD significantly accelerates the carbonation process of steel slag, with a particular boost to the carbonation of β-dicalcium silicate (β-C2S), a key mineral contributing to the carbonation activity. At an optimal β-CD concentration of 2.5 %, the compressive strength of the treated slag reached a peak of 138.5 MPa, marking a 13.4 % improvement over the control sample. Similarly, the CO2 uptake was optimized at 17.9 %, increasing by 21.8 %. Mechanism analysis reveals that β-CD not only facilitates carbonation but also refines the resulting carbonation products, leading to a denser microstructure and enhanced mechanical properties. However, at a β-CD content of 5.0 %, the carbonation process was hindered by excessive viscosity. These pivotal findings propose an innovative strategy to augment the efficiency of carbonation and the inherent material properties of steel slag, thereby fostering a more sustainable approach to the utilization of industrial byproducts.