2020 Volume 18 Issue 3 Pages 129-138
High-magnesium nickel slag (HMNS) and phosphogypsum (PG) are hazardous industrial solid waste. The present work focuses on the feasibility of using the two materials as supplementary cementitious materials (SCM) added to cement. The slag and gypsum were ground into different specific surface area (2235 cm2/g, 3040 cm2/g and 3900 cm2/g), then mixed into ten different samples. The effect of SCM addition was detected by isothermal conduction calorimetry (ICC) testing, compressive strength, mercury intrusion porosimetry (MIP), X-ray diffraction (XRD), scanning electron microscope (SEM) and linear shrinkage. The results showed that the HMNS-PG composite cementitious material with suitable specific surface area has relatively high activity, and a small amount of gel and alumina-ferric oxide-trisulfate (AFt or ettringite) are detected in HMNS-PG composite cementitious material. According to the results, the high-magnesium nickel slag could be together with phosphogypsum as substitutes for cement, improved the utilization rate of industrial waste and reduced environmental pollution.