- Calorimetric study on hydration of CaO-based oxides
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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.
- Iguchi,Narushima,Izumi
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- Synthesis and characterization of an oxidized wustite stabilized by a trace of calcium
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By thermal decomposition of CaFe5O7 at 1125°C in a sealed silica tube during about ten days, we obtained the oxide Fe0.832Ca0.028O1 referred to as 'Fe6O7'. Like wustite, it is iron deficient, very rich in iron (III) cations (Fe2+/Fe3+ = 1.97), has the rock-salt structure (a = 429.4 pm), but the x-ray diffraction pattern does not show satellite reflections around the Bragg peaks. Like wustite, 'Fe6O7' is antiferromagnetic (TN = 207 K), but the room temperature Mossbauer spectrum is different. It seems that this phase is stabilized by traces of calcium and that there is no tetrahedral interstitial iron (III).
- Tazi, A.,Gerardin, R.,Jeannot, F.,Evrard, O.
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- Structural evolution study of substituted wustites Fe1-z-y(Ca, Mg)yO
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Polycrystalline samples of magnesio- and calciowustites Fe(1-z-y)MeyO with Me = Mg or Ca, were investigated using neutron diffraction experiments. The effective chemical composition was controlled by taking into account Vegard's law
- Carel, Claude,Gavarri, Jean-Raymond
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p. 1131 - 1136
(2008/10/08)
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