Study on influencing factors of f-CaO and f-MgO content in steel slag

Steel slag as a large stock of bulk of industrial solid waste in our country, the current domestic of its utilization is only 30% or so. The main reason limiting the large-scale resource utilization of steel slag is that the f-CaO and f-MgO in it are easy to hydrate in water, resulting in the volume expansion of steel slag. The content of f-CaO and f-MgO in steel slag was determined by EDTA-EG method and NH4Cl-EG method. In this paper, the influence of crushing degree and accumulation height on steel slag is investigated, and the change of f-CaO and f-MgO content in steel slag with time is analyze. The results show that the content of f-CaO and f-MgO in steel slag after grinding is higher than that without grinding, and the content of f-MgO in steel slag is much smaller than that of f-CaO. The steel slag aged for three months under local climate conditions in Inner Mongolia has been basically in a chemically stable state, and the f-CaO and f-MgO in the slag will not be separated in a short period of time, indicating that it continues to participate in the hydration reaction. It is more beneficial to control the content of f-CaO and f-MgO when the steel slag accumulation height is less than 5 m.