Effect of Cr₂O₃ on the clinkerization and carbonation properties of γ-C₂S

Dicalcium silicate (C₂S) has strong CO₂ reactivity and is a possible low-carbon binder. In order to facilitate its industrial production, it is important to evaluate the potential influence of minor elements in the raw material on the performance of γ-C₂S. In this work, the effect of Cr₂O₃, a common impurity in solid wastes, on the structure and carbonation properties of C₂S was investigated. The results show that doping Cr₂O₃ can stabilize the β-C₂S crystalline form at low temperatures, inhibit the transition from β-C₂S to γ-C₂S due to the substitution of Si by Cr to change the silica-oxygen tetrahedra, thereby reduce the degree of carbonation of clinkers. During calcination at 1350 °C, Cr₂O₃ was partially evaporated. The leaching rate of Cr from carbonized clinker decreased significantly and the solidification rate of Cr in carbonized clinker was greater than 89.9 %. This work lays a solid foundation for the low-temperature preparation of β-C₂S from industrial solid wastes.