Na_2O-B_2O_3 系融体中の Fe と Mn の酸化還元平衡

概要

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The Fe^<2+>/Fe^<3+> and Mn^<2+>/Mn^<3+> redox equilibria in the Na_2O-B_2O_3 melts have been individually measured as a function of the melt compositions, temperatures, oxygen partial pressures, and dopant element concentrations. The mutual interaction of these two redox couples has been studied by Electron Spin Resonance (ESR) in the Na_2O・2B_2O_3 melts. The redox ratios of Fe and Mn in the Na_2O-B_2O_3 melts tend to decrease with increasing the dopant concentration. A plot of log [(M^<2+>)/(M^<3+>)] versus -log P_<O_2> indicated a straight line of the slope of 8 and 4 for Fe and Mn, respectively. The values for the reduction enthalpy of Fe and Mn in Na_2O-B_2O_3 melts were found to be 80-120kJ/mol and 40-60kJ/mol, respectively. The redox ratio of Fe and Mn decreased with increasing the X_<Na_2O>/X_<B_2O_3> ratio. It was shown by ESR spectroscopy that the electron exchange reaction : Fe^<2+>+Mn^<3+>=Fe^<3+>+Mn^<2+> proceeded to the right.
社団法人日本鉄鋼協会の論文
1991-02-01