Composition-structure-property relationships of CaO-MO-SiO2 (M = Mg2+, Mn2+) systems derived from micro-Raman spectroscopy

Abstract

The effect of Mn2+ and Mg2+ ions on the distribution of silicate anionic species (Q(n) units, n = 0, 1, 2, 3) in CaO-MO-SiO2 (M = Mn2+, Mg2+) systems was compared by employing micro-Raman spectroscopic analysis. The Q(3)/Q(2) ratio in both systems decreased as the content of MO increased, indicating that the substitution of MO for CaO resulted in depolymerization of the silicate networks, especially in the wollastonite primary area. The Q(3)/Q(2) ratio of the MgO-containing system was higher than that of the MnO-containing system due to the larger ionization potential of Mg2+ ions than Mn2+ ions. Thermophysical properties of the silicate melts, such as viscosity, activation energy of viscous transportation, density, and electrical conductivity of the silicate melts, had a good linear relationship to the Q(3)/Q(2) ratio, indicating that the Q(3)/Q(2) ratio is a good index for the degree of polymerization. The methodology outlined in the present study can be extended to predict the physical properties of silicate melts in glass science, metallurgical slags, and chemical geology. (C) 2012 Elsevier B.V. All rights reserved: