Viscosity modelling of ternary CaO–Al2O3–SiO2 melts assisted by in situ high temperature Raman spectroscopy.

In this study, the evolution of microstructure and its correlation with the viscosity of CaO–SiO 2 -based melts, incorporating various Al 2 O 3 additives, have been investigated by employing in situ high temperature Raman spectroscopy and viscosity model. Raman spectra of the melts were procured at 1823 K by using in situ high temperature Raman spectroscopy. After considering the intricate influences of temperature and Raman scattering cross section (RSCS), the original Raman spectra of aluminosilicate melts underwent calibration. Subsequently, the distribution of microstructure species Q i (i = 0–4) was quantitatively performed through meticulous deconvolution of calibrated Raman spectra. The evolution of Q i species with the increasing Al 2 O 3 content reveals a decrease in Q 1 and Q 2 species, while the fully polymerized Q 4 experiences a continuous and significant growth. Concurrently, Q 3 initially exhibits an upward trend followed by a subsequent decline. The Q i evolution culminates in an overall enhancement of the degree of polymerization. Viscosity was determined by utilizing a rigorously selected viscosity model, elucidating a consistent upward trajectory as Al 2 O 3 content is incrementally added. Furthermore, a quantitative analysis of the relationship between viscosity and structure was conducted based on the average number of non-bridging oxygen per network-forming tetrahedron (NBO/T). The findings demonstrate a robust linear relationship between the logarithm of viscosity and NBO/T, thereby offering valuable insights for examining and predicting viscosity behavior of aluminosilicate systems. [ABSTRACT FROM AUTHOR]