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

Park, Joo Hyun

doi:10.1007/s12540-013-3028-4

Cited by 52 publications

(25 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The Raman spectra of the quenched glass samples were collected at room temperature in the range 100-1 900 cm -1 using an Ar excitation laser source having wavelength 514.5 nm coupled with Jobin-Yvon Horiba (LabRam HR, France) micro-Raman spectrometer. [16][17][18][19] Raman shifts were measured with a precision of 0.3 cm . The spectrum data were fitted by Gaussian function with an aid of the 'PeakFit' program within ±0.5% error limit and thus the relative abundance of the Q n i (i=Si and Al) units was calculated from the area fraction of the best-fitted Gaussian curves at the frequency for the symmetric stretching vibration of each Q n i unit, which is given in Table 1.…”

Section: Procedures Of Raman Spectra Measurementsmentioning

confidence: 99%

“…The spectrum data were fitted by Gaussian function with an aid of the 'PeakFit' program within ±0.5% error limit and thus the relative abundance of the Q n i (i=Si and Al) units was calculated from the area fraction of the best-fitted Gaussian curves at the frequency for the symmetric stretching vibration of each Q n i unit, which is given in Table 1. [16][17][18][19] Figure 3 shows a typical deconvolution result for the CaO-Al2O3-8 wt% SiO2-5 wt% MgO-10 wt% CaF2 (CaO/ Al2O3=1.2) system. Peak identification at a specific wavenumber is listed in Table 2.…”

Section: Procedures Of Raman Spectra Measurementsmentioning

confidence: 99%

See 1 more Smart Citation

Structure-Viscosity Relationship of Low-silica Calcium Aluminosilicate Melts

Kim¹,

Park²

2014

ISIJ Int.

Self Cite

148

View full text Add to dashboard Cite

The structure-viscosity relationship of the low-silica (SiO2 ≤ 10 wt%) calcium aluminosilicate melts, which represent the secondary refining ladle slag systems, was investigated by employing the rotatingcylinder viscosity measurement in conjunction with the Raman spectroscopy measurement for linking the macroscopic thermophysical property and molecular (ionic) structural information. Furthermore, the influence of CaF2 on the structure-property relationship was explored. The viscosity of low-silica calcium aluminosilicate melts decreased with increasing both CaO/Al2O3 and CaO/SiO2 ratios. However, the effect of the former on the viscosity of low-silica calcium aluminosilicate melts was larger than that of the latter. By employing the Neuville's structure model, in which the silicate structural units with various NBO, i.e. Q n Si are located at the boundary of the AlO4 aluminate, and the Raman scattering data of the glass samples, it was demonstrated that the aluminate and silicate units are more effectively modified by increasing the CaO/Al2O3 ratio at fixed silica content. The addition of small amounts of CaF2 (~5 wt%) to the low-silica calcium aluminosilicate melts decreased the viscosity of the melts. From the analysis of Raman scattering data, the liberation of SiO4 4-(Q 0 Si) units from the AlO4 aluminate structure by addition of CaF2 was understood. However, the effect of CaF2 addition on the viscosity became less discernible at higher CaF2 content (≥ 10 wt%) region, where the F ions simply substitute for the non-bridging oxygen ions in AlO4 tetrahedra.KEY WORDS: structure; viscosity; low-silica calcium aluminosilicate; ladle slag; Raman spectroscopy; thermophysical property; non-bridging oxygen (NBO); calcium fluoride (CaF2).

show abstract

Section: Procedures Of Raman Spectra Measurementsmentioning

confidence: 99%

Section: Procedures Of Raman Spectra Measurementsmentioning

confidence: 99%

Structure-Viscosity Relationship of Low-silica Calcium Aluminosilicate Melts

Kim¹,

Park²

2014

ISIJ Int.

Self Cite

148

View full text Add to dashboard Cite

show abstract

“…The organic relationships between the silicate structure and the thermodynamic properties of oxide melts such as the mixing free energy of silicates and sulfide capacity have been reported. 10,11) In particular, Park 12,13) demonstrated that the sulfide capacity is strongly affected by the structure of the CaO-SiO 2 -MnO system, and that the excess free energy of MnO is inversely proportional to the degree of polymerization by employing Raman spectra analysis in conjunction with a computational thermodynamic assessment. Therefore, the influence of the silicate structure on the activity coefficient of MnO should be thoroughly investigated.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic Behavior of Manganese Oxide in Lime-based Manganese Smelting Slags

Eom

Lee

Park³

et al. 2016

ISIJ International

View full text Add to dashboard Cite

The thermodynamic behavior of MnO in the CaO-SiO 2 -MnO slag system of lower basicity to understand the smelting reduction of silicomanganese was investigated. Experimental results indicated that the activity coefficient of MnO was not affected by MnO content less than 30 mol%. However, it did in fact increase as the MnO content increased beyond 30 mol% because the activity coefficient of MnO is closely associated with the silicate structure. The activity coefficient of MnO also increased with increasing basicity of slag and MgO content because of the free O 2 − ions that are provided into the slag. On the other hand, the effect of the Al 2 O 3 content on the activity coefficient of MnO was analyzed that the structure in the CaO-SiO 2 -MnO-Al 2 O 3 system changes from that of a Si-O-Si linkage to that of Si-O-Al and Al-O-Al linkages as the content of Al 2 O 3 increases. Structural considerations concerning the effect of slag composition on the activity coefficient of MnO are discussed in detail using Fourier transform infrared (FT-IR) spectroscopy. Finally, it is shown that manganese recovery can be increased by increasing the activity coefficient of MnO in the slag.

show abstract

“…The chemical form of oxygen atoms in glasses is particularly important for determining the physical and chemical properties of important geochemical and metallurgical glasses and melts. [1][2][3][4][5][6][7][8] Despite the recent progress, there is considerable debate and controversy about the chemical forms of oxygen, especially for alkali [9][10][11][12][13][14][15] and alkaline earth [16][17][18][19][20][21][22][23][24][25][26] glasses. The controversy is focused on the existence and concentration of so-called "free oxide" (oxide bound only to alkali or alkaline earth cations).…”

Section: Introductionmentioning

confidence: 99%

“…For example, recent 29 Si NMR papers on magnesium−calcium silicate glasses MgSiO 3 , CaSiO 3 , and Mg 2 SiO 4 , [16][17][18][19] an 17 O NMR study of (Ca,Mg) 2 SiO 4 , 20 and an X-ray and neutron diffraction study of (Ca,Mg)SiO 3 glasses 21 report free oxide contents between 1 and 5 mol% for the metasilicates and between 5 and 7 mol% for the orthosilicates. Three recent Raman papers in the metallurgical and glass literature [22][23][24] report comparable or larger amounts of free oxide for magnesium−calcium silicates from 50 mol% (Ca,Mg)O to 66.7 mol% (Ca,Mg)O above which free oxide must exist from the stoichiometry of reaction 1. In contrast, the most recent 17 O and 29 Si NMR papers on a 56 mol% CaO glass 25,26 either do not mention free oxide 25 or imply that free oxide cannot be present above the 1 mol% level if the glass has a mol% CaO less than 66.7%.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic studies of oxygen speciation in potassium silicate glasses and melts

et al. 2015

View full text Add to dashboard Cite

To resolve discrepant results between O1s XPS and 29 Si and 17 O NMR techniques, O1s XPS spectra were collected and fitted for 15 potassium silicate glasses containing 10−37 mol% K 2 O. The effects of melting on the compositions of the glasses are documented and quantified, as are uncertainties associated with fitting the O1s spectra. These spectra are well resolved into two symmetric peaks: a narrow peak due to NBO (Si−O−K) plus "free oxide" (O 2-or K−O−K) and a broader peak due to BO (Si−O−Si). Values of mol% BO (uncertainties of ±1%) are obtained from the computed peak areas and indicate 2.2 (±0.8) mol% O 2-for glasses containing 32 (±1) mol% K 2 O. Reassignment of Q species for previously published 29 Si NMR spectra leads to BO and O 2-values in good agreement with these O1s XPS spectra. A recent 17 O NMR study on potassium silicate glasses concluded that there is <1 mol% O 2-in these glasses based mainly on the assumption that the 17 O chemical shift for O 2-should be similar in the glasses and the oxide in crystalline K 2 O. This assumption is questionable. Free oxide in these glasses should be highly reactive toward gases such as CO 2 (via CO 2 + O 2-¡ CO 3 2-) and it seems likely that the reactive species in silicate glasses is O 2-rather than NBO as often assumed. The small amounts of CO 2 found in reacted glasses are qualitatively consistent with the abundance of O 2-obtained from these O1s XPS spectra of silicate glass. Key words: potassium silicate glasses, free oxide, O1s XPS, 29 Si, 17 O NMR. Résumé : Afin de résoudre les disparités entre les résultats des techniques de spectrométrie de photoélectrons XPS O1s et RMN 29 Si et 17 O, nous avons enregistré les spectres XPS O1s de 15 verres silicatés de potassium contenant de 10 à 37 mol % de K 2 O et les avons soumis à l'analyse de pic par ajustement. Les effets de la fonte sur la composition des verres sont documentés et quantifiés, ainsi que les incertitudes associées à l'analyse de pic par ajustement des spectres XPS O1s. Ces spectres montrent deux pics symétriques en bonne résolution : un pic étroit, attribuable à l'oxygène non pontant (Si−O−K) et à « l'oxyde libre » (O 2-ou K−O−K), et un pic plus large, attribuable à l'oxygène pontant (Si−O−Si). Les taux d'oxygène pontant en mol % (incertitudes de ±1 %) sont obtenus à partir des valeurs calculées de l'aire des pics et se situent à 2,2 (±0,8) mol % d'O 2-pour les verres contenant 32 (± 1) mol % de K 2 O. La redéfinition des espèces Q à partir de données spectrales RMN 29 Si déjà publiées mène à des taux d'oxygène pontant et d'O 2-en concordance avec ces spectres XPS O1s. Une récente analyse RMN 17 O portant sur des verres silicatés de potassium a permis de conclure que ces verres contenaient moins de 1 mol % d'O 2-, principalement selon l'hypothèse que le déplacement chimique de l' 17 O des atomes d'O 2-dans les verres devrait être semblable à celui des oxydes dans le K 2 O cristallin. Cette hypothèse est contestable. Dans ces verres, l'oxyde libre devrait réagir fortement avec les gaz comme le CO 2...

show abstract

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

Cited by 52 publications

References 46 publications

Structure-Viscosity Relationship of Low-silica Calcium Aluminosilicate Melts

Structure-Viscosity Relationship of Low-silica Calcium Aluminosilicate Melts

Thermodynamic Behavior of Manganese Oxide in Lime-based Manganese Smelting Slags

Spectroscopic studies of oxygen speciation in potassium silicate glasses and melts

Contact Info

Product

Resources

About