EFFECT OF WATER VAPOR ON THE ACTIVITIES OF FeO AND MgO IN SLAGS RELEVANT TO A NOVEL FLASH IRONMAKING TECHNOLOGY

摘要

As part of developing a novel flash ironmaking technology, the activity of iron oxide and the solubility of MgO in slags were studied under three different gas atmospheres: H_2/H_2O, CO/CO_2/H_2/H_2O, and CO/CO_2. The first two gas mixtures represent, respectively, the cases of using hydrogen and natural/coal gas. The CO/CO_2 mixture was investigated for comparison. The slags investigated were MgO-saturated in the temperature range 1550-1600°C with CaO/SiO_2 of 0.8 to 1.4 and pO_2 = 10~(-10)～2×10~(-9) atm. Water increased the activity coefficient of FeO in slag. An empirical correlation for γ_(Feo) in slags under H_2/H_2O atmospheres was formulated: log γ FeO=-3.0623 X_(FeO)-3.1421 X_(CaO)-2.5068 X_(MgO) + 2.1957MgO solubility decreased with basicity and the content of FeO and increased with temperature and pH_2O. The following correlation was developed for MgO solubility: (MgO wt％)=9l.4-0.43 (FeO wt％)-0.54(CaO wt%)-9.34×10~4/T(K).