Effect of CaO/SiO₂ and MgO/Al₂O₃ on the Metallurgical Properties of Low Boron-Bearing High Alumina Slag

It is crucial for the efficiency and the productivity of operations that the viscous flow behavior of the CaO-SiO2-MgO-Al2O3-B2O3 blast furnace slag systems. In this paper, the effects of CaO/SiO2 and MgO/Al2O3 on the viscosity, the break point temperature (TBr) and activation energy (Eη) of low boron-bearing high alumina slag were considered in detail. Meanwhile, the effect mechanisms of CaO/SiO2 and MgO/Al2O3 on slag viscous behavior were expounded using the X-Ray Diffraction (XRD), Fourier transformation infrared spectroscopy (FTIR) and the Factsage. The results show that, with the increasing of CaO/SiO2 from 1.10 to 1.30，the viscosity at 1773 K decrease from 0.316 Pa·s to 0.227 Pa·s ,the TBr and Eη increase from 1534 K and 117.01 kJ·mol-1 to 1583 K and 182.86 kJ·mol-1 respectively. With the increasing of MgO/Al2O3 from 0.40 to 0.65，the viscosity at 1773 K and the TBr decrease from 0.290 Pa·s and 1567 K to 0.208 Pa·s and 1542 K respectively. The deterioration of slag behaviors is due to the increase of polymerization degree of complex viscous units in the slag. Ultimately, when CaO/SiO2 at 1.25 and MgO/Al2O3 at 0.55, the viscous behaviors of slag are better.