Effects of Transition Metal Oxides on Thermal Conductivity of Mould Fluxes

Qiu, Xin; Xie, Bing; Qing, Xue-mei; Diao, Jiang; Huang, Qiao; Wang, Shui-bo

doi:10.1016/s1006-706x(13)60192-2

Cited by 14 publications

(7 citation statements)

References 12 publications

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“…Owing to the modification of the transient hot‐wire method, the thermal conductivity has been successfully measured in various molten oxide systems at high temperature . Several studies have revealed that the thermal conductivity of the molten oxide system is closely related to the network structure.…”

Section: Introductionmentioning

confidence: 99%

“…Owing to the modification of the transient hot-wire method, the thermal conductivity has been successfully measured in various molten oxide systems at high temperature. 2,[5][6][7][8][9][10][11][12][13][14][15][16][17] Several studies have revealed that the thermal conductivity of the molten oxide system is closely related to the network structure. The depolymerization of the silicate network within the SiO 2 -bearing oxide system results in a decrease of the thermal conductivity.…”

Section: Introductionmentioning

confidence: 99%

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Thermal Conductivity of Molten Li₂O–B₂O₃ and K₂O–B₂O₃ Systems

Kim

Morita

2015

J. Am. Ceram. Soc.

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Using the transient hot-wire method, the thermal conductivity properties of the molten Li 2 O-B 2 O 3 and K 2 O-B 2 O 3 systems were measured. The thermal conductivity increases with decreasing the temperature due to the borate structure change. In addition, calculations of the one-dimensional Debye temperature and the phonon mean free paths as a function of temperature of the alkali borate systems were made. At a fixed temperature of 1273 K, the effect of the alkali oxide concentration on the thermal conductivity was evaluated. Within a range of 10-30 mol% Li 2 O (or K 2 O), a positive relationship between the thermal conductivity and 4-coordinate boron was obtained. However, below 10 mol% Li 2 O (or K 2 O), the change in the intermediate-range order of the borate structure had a more dominant effect on the thermal conductivity. Finally, the effect of cations on the thermal conductivity in the various molten R 2 O-B 2 O 3 (R=Li, Na and K) systems was considered. Depending on the type of cation, the change in the ionization potential had an effect on the thermal conductivity and also resulted in a change in the bond strength.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Thermal Conductivity of Molten Li₂O–B₂O₃ and K₂O–B₂O₃ Systems

Kim

Morita

2015

J. Am. Ceram. Soc.

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“…For high-Mn steels with low Al content, the thermal conductivity of CaO-SiO 2 -based mold flux decreased with increasing MnO contents. 117) With MnO additions, O 2 − depolymerized the complex silicate networks, resulting in the disaggregation of the cuspidine and the generation of the tephroite (Mn 2 SiO 4 ) phase, which has poor conductivity and a lower melting point, thereby leading to lower conductive heat transfer. 118) For high-Mn and high-Al steels, an increase in Al 2 O 3 / SiO 2 promotes the primary phase to change from cuspidine to gehlenite with a higher crystallization temperature, thereby inhibiting heat transfer by decreasing the thermal conductivity of the slag film, as shown in Fig.…”

Section: Heat Transfer Behaviormentioning

confidence: 99%

Review on the High-Temperature Thermophysical Properties of Continuous Casting Mold Fluxes for Highly Alloyed Steels

Wang

Sohn

2020

ISIJ Int.

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Several recently developed highly alloyed steel grades have shown unsurpassed performance in terms of physical, chemical, and electromagnetic properties. However, broader commercialization of these steels has been hampered by limitations in mold flux performance. Newly developed steels containing considerable amounts of dissolved Al, Mn, and Ti actively react with typical CaO-SiO 2-based mold fluxes, which severely changes the composition and subsequently the thermophysical properties of the mold flux that determine the external and internal quality of the as-cast steels. These dynamic changes result in nonuniform heat transfer, lubrication issues, surface defects, and caster breakouts. This work critically assesses the current status of the high-temperature thermophysical properties of CaO-SiO 2-based and CaO-Al 2 O 3based mold fluxes intended for use in casting highly alloyed steel grades. Thermophysical properties, including viscosity, crystallization, thermal conductivity, and heat flux, have been evaluated. The effect of compositional variables including CaO/SiO 2 , CaO/Al 2 O 3 , and Al 2 O 3 /SiO 2 mass ratios and the additions of CaF 2 , B 2 O 3 , Li 2 O, K 2 O, Na 2 O, TiO 2 , and BaO on these high-temperature thermophysical properties are discussed.

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“…Therefore, understanding of thermal conductivity of mold flux system is practically important in terms of quality control. Many studies [8][9][10][11] have been carried out in order to find out the relationship between structure of mold flux system and thermal conductivity at high temperature of molten state. These works [8][9][10][11] commonly observed the structure dependence of thermal conductivity.…”

Section: Introductionmentioning

confidence: 99%

“…Many studies [8][9][10][11] have been carried out in order to find out the relationship between structure of mold flux system and thermal conductivity at high temperature of molten state. These works [8][9][10][11] commonly observed the structure dependence of thermal conductivity. Addition of basic oxide, such as sodium oxide or calcium oxide, decreases thermal conductivity as a result of depolymerization of silicate network structure [8,11].…”

Section: Introductionmentioning

confidence: 99%

Thermal Conductivity Measurement of the Molten Oxide System in High Temperature

Kim¹,

Kang²,

Morita³

2018

Impact of Thermal Conductivity on Energy Technologies

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In spite of practical importance in the pyro-metallurgy process, thermal conductivity of molten oxide system has not been sufficiently studied due to its notorious convection and radiation effects. By an aid of appropriate modification of measurement technique and evaluations for systematic errors, thermal conductivity measurement at high temperature becomes feasible. In this chapter, thermal conductivity measurement technique for high-temperature molten oxide system was discussed along with related experimental errors. In addition, thermal conduction mechanism by phonon was briefly introduced. The laser flash method and hot-wire method, which are representative measurement methods for high-temperature system, were compared. During the measurement by using hot-wire method, the convection and radiation effects on measurement results were evaluated. In the hot-wire method, both convection and radiation effects were found to be negligible within short measurement time. Finally, the effect of network structure of molten oxide system on thermal conductivity was discussed. The positive relationship between thermal conductivity and polymerization in the silicate and/or borate system was presented. In addition, the effect of cation expressed by function of ionization potential on thermal conductivity was also briefly introduced. This chapter is partially based on a dissertation submitted by Youngjae Kim in partial fulfillment of the requirements for the degree of Doctor of Philosophy at

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Effects of Transition Metal Oxides on Thermal Conductivity of Mould Fluxes

Cited by 14 publications

References 12 publications

Thermal Conductivity of Molten Li₂O–B₂O₃ and K₂O–B₂O₃ Systems

Thermal Conductivity of Molten Li₂O–B₂O₃ and K₂O–B₂O₃ Systems

Review on the High-Temperature Thermophysical Properties of Continuous Casting Mold Fluxes for Highly Alloyed Steels

Thermal Conductivity Measurement of the Molten Oxide System in High Temperature

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Effects of Transition Metal Oxides on Thermal Conductivity of Mould Fluxes

Cited by 14 publications

References 12 publications

Thermal Conductivity of Molten Li2O–B2O3 and K2O–B2O3 Systems

Thermal Conductivity of Molten Li2O–B2O3 and K2O–B2O3 Systems

Review on the High-Temperature Thermophysical Properties of Continuous Casting Mold Fluxes for Highly Alloyed Steels

Thermal Conductivity Measurement of the Molten Oxide System in High Temperature

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Product

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Thermal Conductivity of Molten Li₂O–B₂O₃ and K₂O–B₂O₃ Systems

Thermal Conductivity of Molten Li₂O–B₂O₃ and K₂O–B₂O₃ Systems