Viscosities of CaO–SiO2–Al2O3–(R2O or RO) Melts

Sukenaga, Sohei; Saito, Noritaka; Kawakami, Kiyoshi; Nakashima, Kouichi

doi:10.2355/isijinternational.46.352

Cited by 139 publications

(123 citation statements)

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“…It was found that viscosity decreases with increasing the additive content of Li 2 O or Na 2 O, whereas the tendency is opposed for K 2 O. [1] Kim et al [2] studied the viscosity variation of CaO-SiO 2 -Al 2 O 3 -MgO-K 2 O system with K 2 O, and the same conclusion was also found that adding K 2 O would increase viscosity. However, the interpretation to this phenomenon is still inexplicit.…”

Section: Introductionmentioning

confidence: 61%

“…During the ironmaking process in blast furnace (BF), the alkali oxide not only results in many operating problems, such as burden movement, erratic change in permeability, and scaffolding in the furnace on the furnace wall, but also greatly affects the viscosity of slag, which is very important for BF operation. Sukenaga et al [1] measured the effect of R 2 O (R = Li, Na, K) on the viscosity of CaO-SiO 2 -Al 2 O 3 melt when keeping the ratio of CaO, SiO 2 , and Al 2 O 3 constant. It was found that viscosity decreases with increasing the additive content of Li 2 O or Na 2 O, whereas the tendency is opposed for K 2 O.…”

Section: Introductionmentioning

confidence: 99%

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Measuring and Modeling Viscosity of CaO-Al2O3-SiO2(-K2O) Melt

Zhang

Chou

2012

Metall Mater Trans B

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The effect of K 2 O on viscosity in CaO-SiO 2 -Al 2 O 3 melt has been measured by a rotating spindle viscometer. It is indicated from the experimental results that viscosity first increases then decreases with the increasing content of K 2 O; the maximum viscosity occurs in the field of K 2 O/ Al 2 O 3 > 1. After gradually adding K 2 O, the transformation of bridging oxygen (from being bonded with Al 3+ ion charge compensated by Ca 2+ ion to that compensated by K + ion, for the higher priority of K + ion relative to Ca 2+ ion) increases the viscosity, whereas the increase of content of nonbridging oxygen decreases viscosity. The two factors lead to the complicate variation behavior of viscosity. The viscosity model proposed in our previous papers describes this phenomenon well.

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Section: Introductionmentioning

confidence: 61%

Section: Introductionmentioning

confidence: 99%

Measuring and Modeling Viscosity of CaO-Al2O3-SiO2(-K2O) Melt

Zhang

Chou

2012

Metall Mater Trans B

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“…In fact, alkali oxide additives (Li2O, Na2O, and K2O) can effectively decrease the viscosity of calcium silicate melts that do not contain Al2O3. 6,7) In contrast, it has been found 8) that the viscosity of certain CaO-SiO2-Al2O3 melts (CaO/SiO2 molar ratio = 0.7-1.3, Al2O3 content = 10-14 mol%) increases after the addition of K2O, even though the degree of polymerization of the aluminosilicate network should decrease after the addition. Similar phenomena have been observed by other researchers as well.…”

Section: Introductionmentioning

confidence: 83%

Effect of Potassium Oxide Addition on Viscosity of Calcium Aluminosilicate Melts at 1673–1873 K

et al. 2014

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We investigated the changes induced in the viscosities of CaO-SiO2-Al2O3-K2O melts (CaO/SiO2 molar ratio = 0.68 ± 0.04, Al2O3 content = 13.4 ± 0.6 mol%) with the addition of K2O in amounts of 0-17.4 mol% for temperatures of 1 673-1 873 K using the rotating crucible method. The viscosity increased with an increase in the K2O content when K2O/Al2O3 molar ratio < 0.7. On the other hand, the viscosity decreased with the addition of K2O for K2O/Al2O3 molar ratio > 0.9. The maximum values of the viscosities were noticed in the range of 0.7 < K2O/Al2O3 molar ratio < 0.9. This behavior could not be explained on the basis of the polymerization degree of the aluminosilicate network structure. The 17 O magic angle spinning nuclear magnetic resonance (MAS NMR) spectrum of the 31.6CaO-44.2SiO2-13.4Al2O3-10.8K2O (mol%) glass suggested that K + ions preferentially compensate the negative charge of AlO4, while the Ca 2+ ions primarily create non-bridging oxygens (NBOs). The viscosity data and the 17 O MAS NMR spectrum also suggested that the increase in viscosity for K2O/Al2O3 molar ratio < 0.7 was because of the increase in the average bond strength of the aluminosilicate framework, which was attributable to the substitution of Ca 2+ ions by K + ions at the charge compensator sites. The activation energies for viscous flow indicated that the NBOs bonded with K + ions, forming NBO-K species, for K2O contents greater than those corresponding to the viscosity maxima. Thus, the viscosities of aluminosilicate melts are indicative of the average bond strengths of the melts.KEY WORDS: viscosity; K-Ca aluminosilicate melts and glasses;17 O MAS NMR spectroscopy.

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“…13,14) In the present paper, we measured the density and the surface tension of CaO-SiO2-Al2O3-R2O (CaO/SiO2=0.67; Al2O3= 20 mass%; R=Li, Na, K) quaternary melts at elevated temperature using the double-bob Archimedean method and the ring method, respectively. Effect of the alkali oxide addition on the density and the surface tension of CaO-SiO2-Al2O3 melt were mainly explored.…”

Section: Introductionmentioning

confidence: 99%

Density and Surface Tension of CaO–SiO2–Al2O3–R2O (R=Li, Na, K) Melts

et al. 2011

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In the present work, we measured the density and the surface tension of CaO-SiO2-Al2O3-R2O (CaO/ SiO2=0.67, Al2O3=20 mass%, R2O=10.8 mol%, R=Li, Na, K) quaternary melts at elevated temperature using the double-bob Archimedean method and the ring method, respectively.The density of the CaO-SiO2-Al2O3-R2O melts decreased with temperature due to the thermal expansion of the melts. In addition, the density of the CaO-SiO2-Al2O3 ternary melt decreased with the addition of the alkali oxides. We converted the density into the molar volume to have a consideration on the microstructure of the melts. The molar volumes of the CaO-SiO2-Al2O3-R2O melts are proportional to cube of the cationic radius for the alkali ions, which indicates the structural roles of the alkali oxides are mainly charge compensator to AlO4 5-anions. The surface tension of the CaO-SiO2-Al2O3-R2O melts changed only slightly with temperature. The surface tension of the CaO-SiO2-Al2O3 ternary melt increased with the addition of Li2O. In contrast, the surface tension decreased with the addition of Na2O or K2O. As for quaternary system, the surface tension increased with the ionic potential of the additive alkali ions; it is the same tendency with the binary alkali silicate melts. However, the mechanism of the surface tension change with the addition of the alkali oxides has not been clarified in the present study.KEY WORDS: density; surface tension; structure of aluminosilicate melts and glasses; CaO-SiO2-Al2O3 based slags; physical property; alkali oxides; charge compensating cation.

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Viscosities of CaO–SiO2–Al2O3–(R2O or RO) Melts

Cited by 139 publications

References 16 publications

Measuring and Modeling Viscosity of CaO-Al2O3-SiO2(-K2O) Melt

Measuring and Modeling Viscosity of CaO-Al2O3-SiO2(-K2O) Melt

Effect of Potassium Oxide Addition on Viscosity of Calcium Aluminosilicate Melts at 1673–1873 K

Density and Surface Tension of CaO–SiO2–Al2O3–R2O (R=Li, Na, K) Melts

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