Effect of silicate structure on thermodynamic properties of calcium silicate melts: Quantitative analysis of Raman spectra

• Published in: Metals and materials international Vol. 19; no. 3; pp. 577 - 584
• Main Author: Park, Joo Hyun
• Format: Journal Article
• Language: English
• Published: Springer The Korean Institute of Metals and Materials 01.05.2013; Springer Nature B.V; 대한금속·재료학회
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Degree of polymerization; Engineering Thermodynamics; Free energy; Heat and Mass Transfer; Machines; Magnetic Materials; Magnetism; Manufacturing; Materials Science; Melts; Metallic Materials; Processes; Quantitative analysis; Silicates; Slags; Solid Mechanics; Sulfides; Sulfur; 재료공학; partial molar excess free energy of mixing; melting; thermodynamic properties; Raman spectroscopy; liquid oxides; sulfide capacity
• ISSN: 1598-9623; 2005-4149
• DOI: 10.1007/s12540-013-3028-4

The distribution of silicate anionic species (Q n units, n=0, 1, 2, 3) and the chemical speciation of oxygen in CaO-SiO 2 -MO (M=Mn and Mg) slags were investigated by micro-Raman spectroscopic analysis. Furthermore, the thermochemical properties were evaluated using a concentration of free oxygen and a degree of polymerization. A good linear relationship was obtained between sulfide capacity and concentration of free oxygen in the CaO-SiO 2 (-MnO) melts at 1500 to 1600 °C. However, even though there was more abundant free oxygen in the CaO-SiO 2 -MgO system than in the CaO-SiO 2 system, the sulfide capacity of the former was lower than the latter, indicating that the sulfur dissolution behavior in the silicate melts cannot be simply explained by the content of free oxygen, because the composition dependency of the stability ratio of oxygen and sulfide ions should be taken into account. The excess free energy of CaO, MgO and MnO linearly decreased as the ln (Q 3 /Q 2 ) increased. The effect of the degree of polymerization on the excess free energy of mixing of MgO-containing slag was larger than that of MnO-containing slag, which was explained by the difference of the ionization potential between Mn 2+ and Mg 2+ ions.