Effect of Coordination Structure of Iron Ions on Absorption of Light in Slags Containing Iron Oxides

本文从（1）炉渣结晶引起的光散射，（2）Fe^<3+>离子配位数的变化和（3）氧离子的给电子能力的观点，研究了含铁氧化物炉渣中电荷转移带的吸收边位移。在0.3- 3 μ m波长范围内对Fe_2O_3-CaO-SiO_2、Fe_2O_3-CaO-SiO_2-Al_2O_3和Fe_2O_3-Na_2 O-SiO_2渣系进行了吸收系数的测定.随着Fe_2O_3含量的增加，吸收边略有向高波长移动，但随着碱度（%CaO）/（%SiO_2）和（%Na_2O）/（%SiO_2）比以及Al_2O_3含量的增加，吸收边明显向高波长移动. X射线衍射显示没有任何样品的结晶相的痕迹。因此，可以得出结论，电荷转移带的吸收边位移不是由于熔渣的结晶。如果Fe^<3+>离子占据四面体配位而不是八面体配位，则铁和氧电子之间的相互作用将变得更小，导致吸收边向更高的波长移动。然而，结果表明，随着四面体对称的Fe^<2+>离子/总Fe^<3+>离子的比率降低，吸收边向更高的波长移动。因此，人们认为吸收边向更高波长的移动与Fe^<3+>离子配位数的变化无关。随着渣中氧离子活度的增加，吸收边向高波长方向移动。因此，有人提出，吸收边的位移是有关的电子给体的功率的氧离子。

The absorption edge shift for the charge transfer band in slags containing iron oxides has been investigated from the viewpoints of (1) the scattering of light due to crystallisation of slags, (2) the change of the coordination number for Fe^<3+> ions and (3) the electron donor power of oxygen ions. Absorption coefficient measurements were made on Fe_2O_3-CaO-SiO_2, Fe_2O_3-CaO-SiO_2-Al_2O_3 and Fe_2O_3-Na_2O-SiO_2 slags in the 0.3-3mum wavelength range.1. The absorption edge was found to move slightly to higher wavelengths with increasing Fe_2O_3 content, but shifted markedly to higher wavelengths with increasing basicity i.e. (%CaO) / (%SiO_2) and (%Na_2O) / (%SiO_2) ratios and Al_2O_3 content.2. X-ray diffraction revealed no traces of crystalline phases forany of the samples. Thus, it has been concluded that the absorption edge shift for the charge transfer band is not due to crystallisation of slags.3. If Fe^<3+> ions occupy tetrahedral coordination sites rather than octahedral coordination sites, interaction between the iron and oxygen electrons will become smaller, resulting in a shift of the absorption edge to higher wavelengths. However, the results have shown that the absorption edge shifts to higher wavelengths as the ratio of (Fe^<2+> ions in tetrahedral symmetry/the total Fe^<3+> ions) decreases. Thus, it has been considered that the absorption edge shift to higher wavelengths is not associated with the change of the coordination number for Fe^<3+> ions.4. The absorption edge was observed to shift to higher wavelengths with increasing the ion refractivity of oxygen in the slags. Consequently, it has been proposed that the absorption edge shift is relevant to the electron donor power of oxygen ions.