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Effect of substituting CaO with BaO on the viscosity and structure of CaO‐BaO‐SiO 2 ‐MgO‐Al 2 O 3 slags
Author(s) -
Wang Zhanjun,
Sohn Il
Publication year - 2018
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.15559
Subject(s) - raman spectroscopy , x ray photoelectron spectroscopy , analytical chemistry (journal) , oxygen , viscosity , slag (welding) , chemistry , polymerization , mineralogy , materials science , nuclear magnetic resonance , metallurgy , polymer , physics , organic chemistry , chromatography , optics , composite material
In this study, the effect of CaO and BaO substitution on the viscosity and structure of CaO‐BaO‐SiO 2 ‐MgO‐Al 2 O 3 slags was investigated. The results showed that the viscosity increased with an increase in the BaO substitution concentration, which was correlated to an increase in the degree of polymerization ( DOP ) of the slag structural units as the activation energy increased from 207.9 to 263.8 kJ/mol for viscous flow. Deconvolution and area integration of the Raman spectrum of the slag revealed that the ratio of Q 3 /Q 2 (Q i , i is the number of O 0 in a [SiO 4 ]‐tetrahedral unit) increased and NBO /Si (nonbridging oxygen per unit silicon atom) decreased with higher BaO content. It was also observed from the 27 Al magic angles pinning nuclear magnetic resonance ( 27 Al MAS ‐ NMR ) spectrum that the relative proportion of Al IV increased, while that of Al V decreased because of the decrease in the percentage of nonbridging oxygen (O − ), indicating the polymerization of the slag. O 1s X‐ray photoelectron spectroscopy ( XPS ) was also carried out to semi‐quantitatively analyze the various types of oxygen anions present in the slag. The XPS results correlated well with the results obtained from the analysis of the Raman and 27 Al MAS ‐ NMR spectra of the slags and its viscous behavior.