Description:
The feasibility of converting high-iron electric furnace ferronickel slag (EFFS) and high-calcium blast furnace ferronickel slag (BFFS) to refractory materials was assessed by sintering with the addition of low-cost sintered magnesia. The preparation and properties of the refractory materials were investigated and compared based on both thermodynamic and experimental analyses. It was shown that the addition of sintered magnesia could restrain the negative effects of high contents of FeO and CaO in EFFS and BFFS, respectively, with low mass ratios of magnesia to silica (m(MgO)/m(SiO2)), by suppressing the formations of the phases with low melting points, including enstatite, liquid phase, monticellite, and merwinite. Compared to that prepared from BFFS, the refractory material derived from EFFS with higher refractoriness (1663 ºC vs. 1700 ºC), lower bulk density (2.92 g/cm3 vs. 2.70 g/cm3), and larger compressive strength (110.2 MPa vs. 158.5 MPa) was obtained by sintering at 1350 ºC for 3 h with a smaller addition of sintered magnesia (45 wt% vs. 30 wt%). This study proved the possibility of turning different types of ferronickel slag into refractory materials, realizing overall and value-added utilization of the waste