Effects of the Aging Treatment Process on the Properties of Steel Slag

Abstract

This study focused on how aging affected the properties of steel slag. Steel slag was treated using hydrothermal aging and pressure steaming aging techniques to improve its bulk stability. Physical and mechanical characteristics, alkalinity, and mineral constituents, as well as micromorphology of steel slag, were investigated. The results demonstrated that water absorption, crushing value, and abrasion value were all decreased by hydrothermal and pressure steam aging. The f-CaO particle size, total slag hydration time, and slag alkalinity were all lowered by two aging procedures. At 90°C aging for 2 days and 0.6 MPa pressure steaming for 3 h, the Ca(OH)2 and CaCO3 diffraction peaks were strengthened, whereas the f-CaO and f-MgO diffraction peaks were diminished. The f-CaO concentration and compaction pulverization rate steadily dropped as hydrothermal days and steaming pressure increased. The water immersion swelling rate was significantly reduced, which enhanced the slag’s bulk stability. After ageing, scanning electron microscopy revealed increased CaCO3 production and enhanced steel slag stability. The optimal processes are recommended as hydrothermal treatment at 90°C for 2 days and pressure steaming at 0.6 MPa for 3 h.