Effect of Iron Phase on Calcination and Properties of Barium Calcium Sulfoaluminate Cement

In this paper, the effect of iron phase content on the calcination and properties of clinker and barium calcium sulfoaluminate cement was studied. The compressive strength of the samples was tested and combined with an XRD and SEM-EDS analysis, and the microstructure and composition of the barium calcium sulfoaluminate clinker and hydrated samples were characterized. The results showed that the oval-shaped particles were C₂S minerals, and the hexagonal plate-shaped or rhombohedral dodecahedral particles were C_2.75B_1.25A₃S¯. The Ba element was mainly distributed in the barium calcium sulfoaluminate region, and some of it was dissolved in C₂S; the Fe element was distributed between C_2.75B_1.25A₃S¯ and C₂S crystal grains in the form of an iron phase solid solution, which acted as a solvent. When the iron phase composition was C₄AF and the iron phase content was 5%, the early hydration and later strength were better, and the compressive strength after curing for 1, 3 and 28 days was 73.2 MPa, 97.9 MPa and 106.9 MPa, respectively. A proper amount of the iron phase can reduce the eutectic point of the sintered mature material system, increase the amount of liquid phase, reduce the viscosity of the liquid phase, effectively accelerate the migration of mineral ions and promote the formation and growth of minerals.