Application of M?ssbauer spectroscopy and FT-IR to describe coordination of amphoteric ions in structure of glasses from the SiO 2-Na 2 O-MgO-CaO-Al 2 O 3-Fe 2 O 3 system

Glasses from the SiO 2 -Na 2 O-MgO-CaO-Al 2 O 3 -Fe 2 O 3 system include, among others, amorphous materials obtained by the vitrification of industrial slags, ashes, dusts, but also various hazardous wastes (e.g. asbestos) containing a high proportion of Al 2 O 3 and Fe 2 O 3 oxides in their basic composition. The main goal of the work was to evaluate the method of incorporation into the glass structure of amphoteric ions (Fe 2 + , Fe 3 + and Al 3 + ) incorporation into the glass structure and its effect on the glass viscosity. A mixture of 10 wt% and 12 wt% pure Fe 2 O 3 powder and float glass cullet was melted in an electric furnace at 1450 degrees C for 4 hours and then poured onto a steel plate. X-ray results confirmed the amorphous structure of all molten glasses. The viscosity of glasses was examined using linear dilatometry and high-temperature microscopy. Fourier transform infrared (FT-IR) and Mossbauer spectroscopy were used to study the coordination number of amphoteric ions and how they were incorporated into the glass lattice. The research confirmed that the increase in the share of amphoteric metal ions in the coordination number 4 causes the incorporation of these ions into the glass network. Metal ions Fe 2 + , Fe 3 + and Al 3 + occurring in tetrahedral coordination, depositing in the glass network next to Si 4 + ions, strengthen the network and, as a result, can increase its viscosity in the range of forming temperatures.(c) 2023 Elsevier B.V. All rights reserved.