Abstract
The effects of different gas atmospheres on the solubility of MgO in CaO–FeO–Al2O3–SiO2–P2O5–MnO slags were studied in the temperature range of 1550–1650°C with wt-%CaO/wt-%SiO2 of 0·8–1·4 and under pO2 = 10−10 to 10−9 atm. The investigated gas atmospheres were H2/H2O (H2 reductant), CO/CO2H2/H2O (natural/coal gas) and CO/CO2. MgO solubility was found to decrease with basicity and FeO content, and increased with temperature. The following correlation was developed for MgO solubility as a function of slag composition and temperature This correlation adequately predicts MgO solubility in slags with FeO contents of 1–50 wt-%, CaO/SiO2 ratios of 0·4–1·6 and temperatures of 1550–1650°C. In addition, MgO solubility was correlated with temperature and basicity defined as: B = (wt-%CaO+0·7 wt-%FetO+0·59 wt-%MnO)–(0·5 wt-%SiO2+0·6 wt-%Al2O3), as follows The MgO solubility at 1550°C and pO2 of 1·6×10−5 atm, which represent typical ironmaking conditions, was 17, 20 and 26 wt-% respectively for slags under CO/CO2H2/H2O, H2/H2O and CO/CO2. Therefore, water vapour would decrease lining wear, as MgO solubility in slag under H2O containing atmospheres is substantially smaller than that under CO/CO2 in typical ironmaking conditions. It was found also that MgO solubility in slag shows a small increase with increasing pH2O beyond ironmaking conditions.
For the first time, the effects of water vapour on MgO solubility in slag have been determined.
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