Effects of Fe₂O₃ on the properties of ceramics from steel slag

Ferric oxide is one of the key factors affecting both the microstructure and the properties of CaO-MgO-SiO₂-based ceramics. Research on this effect is significant in the utilization of iron-rich solid wastes in ceramics. Ceramic samples with various Fe₂O₃ contents (0wt%, 5wt%, and 10wt%) were prepared and the corresponding physical properties and microstructure were studied. The results indicated that Fe₂O₃ not only played a fluxing role, but also promoted the formation of crystals. Ceramics with 5wt% of Fe₂O₃ addition attained the best mechanical properties with a flexural strength of 132.9 MPa. Iron ions were dissolved into diopside, consequently causing phase transformation from diopside and protoenstatite to augite, thereby contributing to the enhancement of its properties. An excess amount of Fe₂O₃ addition (10wt% or more) resulted in deteriorated properties due to the generation of an excess volume of liquid and the formation of high-porosity structures within ceramics.