Role of B2O3 on the Viscosity and Structure in the CaO-Al2O3-Na2O-Based System

Kim, Gi Hyun; Sohn, Il

doi:10.1007/s11663-013-9953-2

Cited by 125 publications

(75 citation statements)

References 20 publications

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“…The activation energy of the present slag system was between 91 kJ/mol to 243 kJ/mol, which is similar values compared to other B2O3 bearing slag systems. 11,12) The results of the present study show that the activation energy of thermal conductivity decreases with a higher BO1.5 concentration, indicating an increment in the number of thermally broken bonds or a decrement in the required energy to break oxygen bonds. This result seems to be contradictory to the network formation with higher boron oxide concentration explained in section 3.2.…”

Section: Relations Between Activation Energy and Its Molten Structurementioning

confidence: 55%

“…3,4) In this sense, studies pertaining to the relationship between the structure and physical properties of molten oxides have been carried out by a number of researchers with the intent to better design and optimize mold flux systems. [5][6][7][8][9][10][11][12][13] Because of the poor application of the additive rule, 14) and anomalous behavior in alkali/alkali earth oxide bearing systems, 15,16) the effect of boron oxide in mold flux systems has been given particular attention. [11][12][13][17][18][19] Wang et al 19) reported that the addition of B 2 O 3 leads to an increase number of [BO 4 ] tetrahedral units, which play an important role as network forming oxides in CaO-SiO 2 -B 2 O 3 -TiO 2 slag systems.…”

Section: Introductionmentioning

confidence: 99%

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Relationship between Molten Oxide Structure and Thermal Conductivity in the CaO–SiO2–B2O3 System

Kim

Morita

2014

ISIJ Int.

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Using a transient hot-wire method, the thermal conductivity of the CaO-SiO2-B2O3 mold flux system was measured. The effects of temperature, BO1.5 concentration and basicity on the thermal conductivity were considered, along with structural investigation by Raman spectroscopy. It was found that the addition of boron oxide caused both a decrement and increment of thermal conductivity, depending on the basicity. These conflicting effects on thermal conductivity were considered to be caused by the following two different behaviors in the oxide melts. Boron oxide is incorporated into silicate networks at a lower basicity, while it tends to form borate networks at higher CaO/SiO2 ratios. In the case of basicity dependency, thermal conductivity initially decreases or remains constant with increasing CaO/SiO2 ratio in regions of low basicity, but increases when the CaO/SiO2 ratio is higher than 1.15. Due to the incorporated state of boron oxide in silicate networks at low basicity, the thermal conductivity is likely to be predominantly affected by the silicate networks. However, at a relatively high CaO/SiO2 ratio, an increase in chain-type metaborate was observed through Raman spectroscopy; this structural change in borate being responsible for the increment in thermal conductivity with higher basicity. Finally, the apparent activation energy of thermal conductivity was calculated, and was found to be reduced by the addition of boron oxide.

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Section: Relations Between Activation Energy and Its Molten Structurementioning

confidence: 55%

Section: Introductionmentioning

confidence: 99%

Relationship between Molten Oxide Structure and Thermal Conductivity in the CaO–SiO2–B2O3 System

Kim

Morita

2014

ISIJ Int.

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“…9,10) Numerous studies have been thus performed to pursue the network structures of borosilicate glass, which could be categorized into three types based on the three important variables, viz., temperature, pressure and chemical composition. For example, Stebbins et al found a conversion of BO 3 trigonal to BO 4 tetrahedral with increasing temperature.…”

Section: Introductionmentioning

confidence: 99%

Short-range and Medium-range Structural Order in CaO–SiO2–TiO2–B2O3 Glasses

Sun

et al. 2016

ISIJ International

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The present study aimed to provide a deep insight of short-range and medium-range structural order for CaO-SiO 2 -TiO 2 -B 2 O 3 glasses. From various prospects, four techniques, FTIR, Raman, XPS and NMR, were simultaneously employed and only the direct evidences indicated from the spectra were used for structural analysis. The FTIR and Raman spectra proved that the main silicon-related units were Q 0 (Si), Q 1 (Si), Q 2 (Si) and Q 3 (Si) and the results of Raman fittings revealed that a B 2 O 3 addition resulted in an increase of Q 1 (Si) and Q 3 (Si) at the cost of Q 0 (Si) and Q 2 (Si), thus inducing an increasing Degree of Polymerization (DOP). An enhanced DOP generally implied a lower abundance of non-bridging oxygen in the networks, which was further demonstrated by the O1s XPS fittings. Additionally, the 11 B NMR spectra indicated that the dominant boron-related groups were BO 3 trigonal comprising ring and non-ring BO 3 as well as BO 4 tetrahedral comprising BO 4 (1B,3Si) and BO 4 (0B,4Si). Furthermore, it was clarified that an increase of B 2 O 3 content promoted the ratios of BO 4 (1B,3Si) to BO 4 (0B,4Si) and BO 4 tetrahedral to BO 3 trigonal, which undoubtedly identified the occurrence of an equilibrium reaction between NBO, BO 4 tetrahedral and BO 3 trigonal in the glass.

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“…Figure 4 shows the FTIR spectra of the mold fluxes and 600-500 cm − 1 . Referring to previous published results, 11,12,17) different band groups were determined. The absorption peaks at 1 250-1 150 cm 3 ]-triangular unit is formed and its absorptance intensity had a relatively increasing trend, the width of the peak of [BO 3 ] also increases and moves to lower wavelength.…”

Section: )mentioning

confidence: 99%

Viscosity-structure-crystallization of the Ce2O3-bearing Calcium-aluminate-based Melts with Different Contents of B2O3

Liu

Jiang

2018

ISIJ Int.

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In order to restrain the slag-metal interface reaction in the process of heat resistant steel continuous casting, the aluminate-based mold flux was devised. The effect of B 2 O 3 on the viscosity, structure and crystallization property of the aluminate-based melts was studied. Appropriately adding B 2 O 3 could decrease the viscosity of the melts. However, the viscosity could remain relatively constant when the addition of B 2 O 3 exceeded 5 mass%. The structures of the melts, which were correlated to the viscosity, were confirmed through Fourier transformed infrared spectroscopy. The main network former of the melts was AlO 4 -tetrahedral unit. With adding B 2 O 3 , B 2 O 3 formed 2D BO 3 -triangular unit, the bridging oxygen of the network combined by AlO 4 -units was broken, the polymerization of the melts decreased, and the viscosity, the apparent activation energy decreased consequently. With no B 2 O 3 addition, the main crystalline phase was CaO. Because of Ca-O have the strongest interaction force and the weakest irregular thermal motion. The crystallization of CaO could be restrained by adding B 2 O 3 , the crystalline phase transferred from CaO to LiAlO 2 and CaCeAlO 4 . CaCeAlO 4 precipitated later than LiAlO 2 because of the different interactions and the irregular motion ability of different structure units.

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Role of B2O3 on the Viscosity and Structure in the CaO-Al2O3-Na2O-Based System

Cited by 125 publications

References 20 publications

Relationship between Molten Oxide Structure and Thermal Conductivity in the CaO–SiO2–B2O3 System

Relationship between Molten Oxide Structure and Thermal Conductivity in the CaO–SiO2–B2O3 System

Short-range and Medium-range Structural Order in CaO–SiO<sub>2</sub>–TiO<sub>2</sub>–B<sub>2</sub>O<sub>3</sub> Glasses

Viscosity-structure-crystallization of the Ce<sub>2</sub>O<sub>3</sub>-bearing Calcium-aluminate-based Melts with Different Contents of B<sub>2</sub>O<sub>3</sub>

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