Preparation and properties of calcium aluminate cement with Bayer red mud

Abstract

Aiming at the problems of large discharge, the low utilization rate, and severe environmental pollution of Bayer red mud (BRM), this paper studied the feasibility of preparing calcium aluminate cement (CAC) with BRM as a raw material. The calcination regime of preparing CAC with BRM was investigated in the system of the CaO-Al2O3-SiO2. The experiment was designed by the simplex centroid design method. The optimal proportion range of CAC without BRM was determined with the compressive strength as the index. In addition, the evolution of the microstructure was studied by scanning electron microscope (SEM). Results demonstrate that the phases CA, CA2, and C2AS were formed at a temperature of 1300 °C. It was determined that the best performance was obtained with a Bayer red mud content of 8% by X-ray diffraction (XRD) and hydration heat. Moreover, the strength of CAC designed with Bayer red mud could reach 45.8 MPa after curing for 14 days, which was 18.7 MPa higher than that of CAC prepared without BRM at the same curing age.