Calorimetric study on hydration of CaO-based oxides

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 cal orimetric and dilatometric techniques in order to clarify the effects of Ca O-based oxides on stability of steelmaking slag. Slow hydration rate and la rge volume expansion were observed in 3CaO . Al2O3, which was a harmful com ponent 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 c ontent region than 30-mole%, while the hydration rate decreased as MnO cont ents increased in higher solute content region. Hydration behavior of conve rter slag was dominated by free lime contained in the slag. It was suggeste d that 3CaO . Al2O3 affected hydration behavior of ladle furnace free (LF) slag because Al dissolution was detected after calorimetric measurements ad d slow expansion rates and higher heat of hydration than that calculated wi th free lime contents were observed for LF slag. (C) 2001 Elsevier Science B.V. Ah rights reserved.