Utilization of red mud, slag and waste drilling fluid for the synthesis of slag-red mud cementitious material

Abstract Waste drilling fluid is a kind of residue generated in the drilling process. The traditional treatment of waste drilling fluid, such as solid-liquid separation, chemical degradation, heat treatment, solidification treatment and biochemical degradation, is expensive and complicated. Red mud, which is an industrial by-product produced during the extraction of bauxite, also has problems such as excessive accumulation and difficult to deal with. In this study, a new cementitious material was prepared by using waste drilling fluid, blast furnace slag and red mud for the purpose of environmentally efficient solutions for wastes recycling. The physical and chemical properties of blast furnace slag-red mud cementitious material (SRCM) are evaluated by compressive strength, X-ray diffraction (XRD) analysis and mercury intrusion porosimetry (MIP). The compressive strength results show that the samples can achieve 16.7 MPa. The hydration mechanism of the SRCM is studied by hydration heat analysis and scanning electron microscopy (SEM). The results show that the structure formation of the material is mainly formed by the new amorphous structure. The structure of the SRCM is denser with respect to blank sample without red mud. Toxicity leaching result shows the heavy metal ion content meet the criteria in standard, indicating the new cementitious material is environmental friendly.