5th International Congress on the Science and Technology of Steelmaking 2012.
開催地
和文:
Dresden
英文:
アブストラクト
The concentration change of iron oxide in mould fluxes has been measured to elucidate
its formation kinetics in relation to continuous casting. Three physical and chemical
conditions were changed in experiments, namely oxygen partial pressures in atmosphere,
SiO2 activities in mould flux and oxygen contents in molten iron. Pre-melted mould
fluxes were held in contact with molten electrolytic iron or Al-killed iron in an alumina
crucibles at 1891 K in an argon or air atmosphere for different holding times. The
concentration of iron oxide in mould flux was determined by X-ray fluorescence
analysis. In case of electrolytic iron, iron oxide concentrations increased with holding
times and reached ca 3 mass% within 1.2 ks, independently of ambient gases. This
independence suggests that the oxygen source was not the atmosphere. Higher SiO2
activities resulted in lower concentrations of iron oxide, which suggests that SiO2 would
not contribute to oxidation of molten iron. In case of Al-killed iron, iron oxide
concentrations at maximum decreased to ca 0.5 mass% possibly due to lower oxygen
contents in molten iron. This decrease suggests that oxygen source would be oxygen
contained in molten electrolytic iron. Another finding about the iron oxide profile in
mould fluxes suggests that mass transfer of iron oxide in the boundary layer is the rate
controlling step, which is supported by the fact that a reasonable value of mass transfer
coefficient k (reaction rate constant) of 4 × 10-6 cm?s-1 has been derived on the basis
of the concentration change of iron oxide with time.
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