Effect of water vapour content in H2–H2O–CO–CO2 mixtures on activity of iron oxide in slags relevant to novel flash ironmaking technology

Abstract

As an integral part of developing a novel flash ironmaking technology at the University of Utah, the activity of iron oxide in the slag was studied under three different gas atmospheres: H2/H2O (H2), CO/CO2/H2/H2O (reformed natural/coal gas), and CO/CO2. The conditions of the slags investigated were MgO-saturated CaO–FeO–Al2O3–SiO2–MnO (0·2–0·8 wt-%)–P2O5 (0·1–0·9 wt-%) in the temperature range 1550–1600°C with wt-% CaO/wt-% SiO2 of 0·8 to 1·2, and under pO2 = 2×10−10–2×10−9 atm. Water increased the activity coefficient of FeO in the slag and accordingly lowered the FeO content. The average FeO content was found to be 10, 11 and 16 wt-% under H2/H2O (H2), CO/CO2/H2/H2O (reformed natural/coal gas), and CO/CO2, respectively. An empirical correlation for γFeO in slags under H2/H2O atmospheres was formulated to givelog γFeO = −3·0623 XFeO−3·1421 XCaO−2·5068 XMgO+2·1957