Preparation of high-performance cementitious materials from industrial solid waste

Sulfoaluminate cement exhibits a good dimensional stability, an early strength, a high strength, a high resistance to chemical attack (from seawater, sulfates and chlorides), a low energy consumption and low carbon-dioxide emissions during production. However, sulfoaluminate cement factories traditionally use limestone, bauxite and gypsum as materials, which places significant pressure on these natural resources. This study aimed to investigate the feasibility of substituting traditional raw materials with industrial solid wastes in sulfoaluminate clinker production. It was achieved by sintering a mixture of industrial solid wastes (coal gangue: 8%-15%, flue gas desulfurization gypsum: 25%-35%, aluminum slag: 30%-35%, carbide slag: 30%-35%) at 1150-1300 °C. The mineralogical composition of the clinker was C4A3S‾, C2S and C4AF. The compressive strength of hydrated specimens reached as high as 75 MPa after a 28 d curing. This research provides a feasible and promising way to produce high-value products using industrial solid wastes and may promote their large-scale utilization.