The effect of Fe3+ ions on the anionic structure of iron-bearing sodium silicate melts

The effects of the coordination of iron ions on the anionic structure of mo lten iron bearing sodium silicate slags at 1 273 K have been investigated b y Raman spectroscopy. The Raman spectra of Na2O-SiO2-FeO-Fe2O3 system equil ibrated with various oxygen pressures (pO(2)) have been measured. The effec t of the concentration of iron oxide on the Raman spectra of these systems has also been studied. Under low pO(2) conditions (CO2/CO<10), the Raman spectra of Na2O<bullet>2S iO(2)-FeO-Fe2O3 are essentially the same as that of Na2O . 2SiO(2). However , under high pO(2) conditions (CO2/CO>54), a new Raman band of around 900 c m(-1) appears and its intensity increases with increase of pO(2) and iron o xide content. The scattering intensity at low frequency region (<550 cm(-1) ) also becomes intense with increase of the iron oxide content. It is confirmed that the near 900 cm(-1) band can be attributable to the ne twork structure involving Fe3+ ions. Fe3+ ions in the metasilicate melts is found to conjugate the chain units and produce the sheet and monomer units . In the disilicate melts, it will conjugate the sheet units and produce th e chain and three-dimensional network units.