Reconsideration on Al Coordination in CaO–SiO2–Al2O3–(R2O or RO) Glasses by Using High Field Solid-State 27Al NMR Spectroscopy

Sukenaga, Sohei; Nagahisa, Tetsuya; Kanehashi, Koji; Saito, Noritaka; Nakashima, Kouichi

doi:10.2355/isijinternational.51.333

Cited by 26 publications

(19 citation statements)

References 9 publications

(20 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For a more quantitative analysis of the multiple roles of Al 3+ in the slag network structure, 27 Al MAS‐NMR spectra were carried out, and the unadjusted results are shown in Figure A. In this study, the 27 Al MAS‐NMR spectra reveal a main chemical shift peak at approximately 60 ppm for AlO 4 (Al IV ), with a shoulder on the lower frequency at about 25 ppm for AlO 5 (Al V ) . The peaks typically assigned to the network modifier AlO 6 (Al VI ) near 0 ppm could not be distinguished .…”

Section: Resultsmentioning

confidence: 84%

Effect of substituting CaO with BaO on the viscosity and structure of CaO‐BaO‐SiO₂‐MgO‐Al₂O₃ slags

2018

View full text Add to dashboard Cite

In this study, the effect of CaO and BaO substitution on the viscosity and structure of CaO‐BaO‐SiO2‐MgO‐Al2O3 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 Q3/Q2 (Qi, i is the number of O0 in a [SiO4]‐tetrahedral unit) increased and NBO/Si (nonbridging oxygen per unit silicon atom) decreased with higher BaO content. It was also observed from the 27Al magic angles pinning nuclear magnetic resonance (27Al MAS‐NMR) spectrum that the relative proportion of AlIV increased, while that of AlV decreased because of the decrease in the percentage of nonbridging oxygen (O−), indicating the polymerization of the slag. O1s 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 27Al MAS‐NMR spectra of the slags and its viscous behavior.

show abstract

Section: Resultsmentioning

confidence: 84%

Effect of substituting CaO with BaO on the viscosity and structure of CaO‐BaO‐SiO₂‐MgO‐Al₂O₃ slags

2018

View full text Add to dashboard Cite

show abstract

“…Previous studies determined that the aluminum cations in glasses of similar compositions had mostly four-fold coordination, as determined using 27 Al MAS NMR spectroscopy. [14] As shown in the Table I, the nominal concentration of non-bridging oxygen (NBO/total-O) increased with the addition of alkali oxides, and the value of NBO/total-O is comparable for all alkali oxide-containing systems.…”

Section: A Sample Preparationmentioning

confidence: 89%

Structural Role of Alkali Cations in Calcium Aluminosilicate Glasses as Examined Using Oxygen-17 Solid-State Nuclear Magnetic Resonance Spectroscopy

Sukenaga

Kanehashi

Shibata

et al. 2016

Metall Mater Trans B

Self Cite

View full text Add to dashboard Cite

The structural roles of alkali and calcium cations are important for understanding the physical and chemical properties of aluminosilicate melts and glasses. Recently, oxygen-17 nuclear magnetic resonance ( 17 O NMR) studies of calcium-sodium aluminosilicate glasses showed that these structural roles are not randomly given, but rather each cation has its own preferential role. However, the relationship between cation type and role preference in calcium aluminosilicate glass is not completely understood. In the present study, the structural roles of lithium, sodium, and potassium cations in selected calcium aluminosilicate glasses are investigated using 17 O solid-state NMR experiments. Data from these experiments clearly show that potassium cations have a notably stronger tendency to act as charge compensators within the network structure, compared to sodium and lithium cations. The result of 17 O NMR experiment also showed that sodium and lithium cations in part act as network modifier alongside with calcium cations.

show abstract

“…*The presence of Al-OBO-Al was neglected because it is not main component in the present system. 29) In addition, a previous study indicated a presence of fivefold coordination for Al 3 + as a minor species; 30) however, the coordination number of Si 4 + and Al 3 + can be assumed to be 4 for simplicity in Fig. 4.…”

Section: )mentioning

confidence: 99%

Effect of CaO/SiO2 Ratio on Surface Tension of CaO–SiO2–Al2O3–MgO Melts

et al. 2015

Self Cite

View full text Add to dashboard Cite

The effect of the CaO/SiO 2 molar ratio on the surface tension of calcium aluminosilicate melts containing magnesia (CaO-SiO 2 -Al 2 O 3 -MgO) has been explored using a ring method at 1 723-1 823 K; the Al 2 O 3 and MgO contents were approximately 12 and 8 mol%, respectively. The CaO/SiO 2 molar ratio of the samples was varied in the range of 1.1-1.7. The surface tension of the CaO-SiO 2 -Al 2 O 3 -MgO system simultaneously increased upon increasing the CaO/SiO 2 molar ratio. The present data were compared with the surface tension of the binary calcium silicate (CaO-SiO 2 ) and the ternary calcium aluminosilicate (CaOSiO 2 -Al 2 O 3 ) melts reported in the literatures. The surface tension of the present CaO-SiO 2 -Al 2 O 3 -MgO melts was higher than those of the binary calcium silicate melts and slightly lower than those of the ternary calcium aluminosilicate melts when the polymerization degrees of the melts were comparable. The change in the surface tension was considered from the viewpoint of the local structure of oxygen atoms at the melt surface. Oxygen atoms, which require higher coordination by cations in the bulk, may tend to lose their neighbors at the surface of the melts, which can result in the formation of unsatisfied bonds at the surface. An increase in the number of unsatisfied bonds can yield an increase in the surface tension.KEY WORDS: surface tension; Mg-Ca aluminosilicate melts; blast-furnace-type slag; polymerization degree; negative charge on oxygen atoms.

show abstract

Reconsideration on Al Coordination in CaO–SiO2–Al2O3–(R2O or RO) Glasses by Using High Field Solid-State 27Al NMR Spectroscopy

Cited by 26 publications

References 9 publications

Effect of substituting CaO with BaO on the viscosity and structure of CaO‐BaO‐SiO₂‐MgO‐Al₂O₃ slags

Effect of substituting CaO with BaO on the viscosity and structure of CaO‐BaO‐SiO₂‐MgO‐Al₂O₃ slags

Structural Role of Alkali Cations in Calcium Aluminosilicate Glasses as Examined Using Oxygen-17 Solid-State Nuclear Magnetic Resonance Spectroscopy

Effect of CaO/SiO<sub>2</sub> Ratio on Surface Tension of CaO–SiO<sub>2</sub>–Al<sub>2</sub>O<sub>3</sub>–MgO Melts

Contact Info

Product

Resources

About

Reconsideration on Al Coordination in CaO–SiO2–Al2O3–(R2O or RO) Glasses by Using High Field Solid-State 27Al NMR Spectroscopy

Cited by 26 publications

References 9 publications

Effect of substituting CaO with BaO on the viscosity and structure of CaO‐BaO‐SiO2‐MgO‐Al2O3 slags

Effect of substituting CaO with BaO on the viscosity and structure of CaO‐BaO‐SiO2‐MgO‐Al2O3 slags

Structural Role of Alkali Cations in Calcium Aluminosilicate Glasses as Examined Using Oxygen-17 Solid-State Nuclear Magnetic Resonance Spectroscopy

Effect of CaO/SiO<sub>2</sub> Ratio on Surface Tension of CaO–SiO<sub>2</sub>–Al<sub>2</sub>O<sub>3</sub>–MgO Melts

Contact Info

Product

Resources

About

Effect of substituting CaO with BaO on the viscosity and structure of CaO‐BaO‐SiO₂‐MgO‐Al₂O₃ slags

Effect of substituting CaO with BaO on the viscosity and structure of CaO‐BaO‐SiO₂‐MgO‐Al₂O₃ slags