酸化鉄を含む急冷スラグの光吸収スペクトル

抄録

Liquid slags composed of Na₂O-SiO₂-Fe₂O₃, Na₂O-P₂O₅-Fe₂O₃, and CaO-SiO₂-Al₂O₃-Fe₂O₃ have been equilibrated with various oxygen pressures at 1250°C, 950°C, and 1500°C, respectively. After quenching, the glassy solid slag has been polished on the both sides and the optical absorption spectra have been measured with an optical spectrometer.
A strong charge transfer band and five absorption peaks have been observed. The five peaks are inter preted to be due to electron transitions from the ground state of ⁶A_1g to ⁴T_2g (D), ⁴A_1g^-4E_g (G), and ⁴T_2g (G)(these three are attributed to 3d electrons of Fe3⁺) and from the ground state to ⁵E_g (octahedralsymmetry) and to ⁵T_2g (tetrahedral symmetry);(these two peaks are attributed to 3d electrons of Fe²⁺).
From the peak positions, it is deduced that oxygen anions are located around a ferric cation in the tetrahedral symmetry in Na₂O-SiO₂-Fe₂O₃ slags and in the octahedral symmetry in Na₂O-P₂O₅-Fe₂O₃ slags and around a ferrous cation in both tetra- and octa-hedral symmetries in the all slags studied.
The position of the edge of the observed charge transfer bands shifted to the lower energy position with the increase of the Fe₂O₃ addition, oxygen pressure, and the basicity. From the edge shift, it seems that the charge transfer band is essentially due to electron transitions between the ferric cation and oxygen anion.
The reproducibility of the peak position was within 50cm^-1 (0.006eV) and the relative error in the molar extinction coefficient was estimated to be ±15%.