Hydration behavior of compounds in Ca-(Si, Al or Fe)-O systems, CaO-(FeO or MnO) solid solutions and various kind of slags were investigated using calorimetric and dilatometric techniques in order to clarify the effects of CaO-based oxides on stability of steelmaking slag. Slow hydration rate and large volume expansion were observed in 3CaO·Al2O3, which was a harmful component for stabilizing slag. Heat of hydration and volume expansion of CaO solid solutions were almost the same as those of pure CaO in lower solute content region than 30-mole%, while the hydration rate decreased as MnO contents increased in higher solute content region. Hydration behavior of converter slag was dominated by free lime contained in the slag. It was suggested that 3CaO·Al2O3 affected hydration behavior of ladle furnace free (LF) slag because Al dissolution was detected after calorimetric measurements and slow expansion rates and higher heat of hydration than that calculated with free lime contents were observed for LF slag.
- Heat of hydration