Thermodynamic model of activity for components in CaO-MgO-Al_(2O)3-SiO_2 refining slag system

摘要

The activities of components in the CaO-MgO-Al_(2O)3-SiO_2 refining slags at 1873K were calculated through the coexistence theory. The calculated results of activities of CaO, MgO, A1_2O_3 and SiO_2 were found to be similar to those of experiment tests. The activities of CaO, MgO increase with the increase of basicity and CaO contents, respectively. However, the activities of MgO decrease with the increase content of SiO_2. The activity of A1_2O_3 and SiO_2 is influenced by the basicity, and the activities of Al_(2O3) and SiO_2 decrease with the increase of basicity in wMgO 10% at 1873K. The activity of CaO, MgO, A1_2O_3 and SiO_2 in the CaO-MgO-Al_(2O3)-SiO_2 refining slags (T=1873K, wMgO =7%), has big fluctuation, is the range from 0.2 to 0.5, from 0.18 to 0.25, from 0.02 to 0.006, from 2×l0~(-5) to 2×l0~(-4), respectively. At wMgO 5%, the activity of components in the CaO-MgO-Al_2O_3-SiO_2 refining slags, has small fluctuation, is 0.1-0.5, 0.13-0.18, 0.005-0.02, 2×10~(-5)~1×10~(-3). The thermodynamic calculation of activities of components in GCr15 refining slag provides theoretical foundation for exploring the relationship between refining slag and inclusions in liquid steel.