Effects of CaO/SiO2 Ratio and Na2O Content on Melting Properties and Viscosity of SiO2-CaO-Al2O3-B2O3-Na2O Mold Fluxes

Wang, Lin; Zhang, Chen; Cai, Di; Zhang, Jianqiang; Sasaki, Yasushi; Ostrovski, Oleg

doi:10.1007/s11663-016-0816-5

Cited by 44 publications

(17 citation statements)

References 36 publications

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“…It could be observed, the positions of the peaks in this region are around 850, 900, 970, and 1040 cm −1 , reflecting the stretching vibrations of silicate structural units Q 0 (

Si {normalO}_{4}^{4 -}

) monomers, Q 1 (

{Si}_{2} {normalO}_{7}^{6 -}

) dimers, Q 2 (

Si {normalO}_{3}^{2 -}

) chains or rings, and Q 3 (

{Si}_{2} {normalO}_{5}^{2 -}

) sheets. Here, the superscripts 0, 1, 2, and 3 are the numbers of bridging oxygen (BO) per [SiO 4 ]‐tetrahedra . As proposed by Maehara and other researchers, Raman scattering efficiency of Si–O bond depends on the type of Q n species, however, it is difficult for the authors to determine the exact Q n distribution by another experimental technique nuclear magnetic resonance (NMR) to calibrate the Raman area fraction.…”

Section: Resultsmentioning

confidence: 99%

Viscosity and Structure of CaO–SiO₂–“FeO”–Al₂O₃–MgO System during Iron‐Extracting Process from Nickel Slag by Aluminum Dross. Part 1: Coupling Effect of “FeO” and Al₂O₃

Zhang

Wang

Chen

et al. 2018

steel research int.

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Nickel slag can be recycled as one of excellent secondary sources due to valuable amounts of iron contents. Viscosity of CaO–SiO2–“FeO”–Al2O3–MgO slag system during iron‐extracting process from nickel slag by aluminum dross is investigated from 1723 to 1873 K. Evolution of viscosity and structure are studied with “FeO”/Al2O3 ratio decreasing from 1.69 to 0.48. Under the coupling effect of “FeO” and Al2O3, the viscosity increases slowly before the reduction degree of 60% following by a significant increase. Structure investigation shows that Al2O3 is always acting as the network former, and the transition of dominant role from “FeO” to Al2O3 not only leads to the disappearance of structural unit Q0 in Raman spectra, but also the occurrence of more complex unit Q3, signifying an evident increase in the degree of polymerization (DOP) of the slag. Additionally, the viscosity evolution during the reduction process is calculated upon the non‐isothermal thermodynamic model.

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“…It could be observed, the positions of the peaks in this region are around 850, 900, 970, and 1040 cm −1 , reflecting the stretching vibrations of silicate structural units Q 0 (

Si {normalO}_{4}^{4 -}

) monomers, Q 1 (

{Si}_{2} {normalO}_{7}^{6 -}

) dimers, Q 2 (

Si {normalO}_{3}^{2 -}

) chains or rings, and Q 3 (

{Si}_{2} {normalO}_{5}^{2 -}

Section: Resultsmentioning

confidence: 99%

Viscosity and Structure of CaO–SiO₂–“FeO”–Al₂O₃–MgO System during Iron‐Extracting Process from Nickel Slag by Aluminum Dross. Part 1: Coupling Effect of “FeO” and Al₂O₃

Zhang

Wang

Chen

et al. 2018

steel research int.

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“…(2) The prepared sample was placed in the LZ-III slag melting temperature characteristic tester. (3) With the temperature increased at a rate of 5 °C/min, the corresponding temperature was recorded as the softening temperature, hemisphere temperature and flow temperature, when the sample dropped to 75%, 50%, and 25%, respectively [16,17]. Throughout the process, 300 mL/min of Ar was used as the protecting gas.…”

Section: Methodsmentioning

confidence: 99%

Viscosity and Structure of a CaO-SiO2-FeO-MgO System during a Modified Process from Nickel Slag by CaO

et al. 2019

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There is a high iron content in nickel slag that mainly exists in the fayalite phase. Basic oxide can destroy the stable structure of fayalite which is beneficial to the treatment and comprehensive utilization of nickel slag. The research was based on the composition of the raw nickel slag, taking the CaO-SiO2-FeO-MgO system as the object and CaO as a modifier. The effect of basicity on the melting characteristics, viscosity and structure of the CaO-SiO2-FeO-MgO system was studied. The relationship between the viscosity and structure of the CaO-SiO2-FeO-MgO system was also explored. The results show as follows: (1) When the basicity is lower than 0.90, the primary phase of the slag system is olivine phase. When the basicity is greater than 0.90, the primary phase of the slag system transforms into monoxide. When the basicity is 0.90, olivine and monoxide precipitate together as the temperature continues to decrease. At the same time, the liquidus temperature, softening temperature, hemispherical temperature, and flow temperature all reach the lowest value. (2) With the increase of basicity, the critical viscosity temperature of the CaO-SiO2-FeO-MgO system decreases first and then increases. Critical viscosity temperature is the lowest at the basicity of 0.90, which is 1295 °C. (3) When the slag system is heterogeneous, the viscosity of the molten slag increases rapidly because of the quantity of solid phase precipitated from the CaO-SiO2-FeO-MgO system. (4) When the slag system is in a homogeneous liquid phase, the molar fraction of O0 decreases with the increase of basicity and the mole fraction of O−, and O2− increases continuously at the basicity of 0.38~1.50. The silicate network structure is gradually depolymerized into simple monomers, resulting in the degree of polymerization, and the viscosity, being reduced. The mole fraction of different kinds of oxygen atoms is converged to a constant value when the basicity is above 1.20.

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“…At the same time, the change in sample height was observed through the video image-recording system, as shown in Figure 2. Melting characteristics, including the softening temperature (T s ), hemisphere temperature (T h ), and "fluidity temperature (T f ), were defined according to the sample heights of 75%, 50%, and 25%, compared with the original height, respectively [14]. These three temperatures are generally used to characterize the melting trajectory of flux in industrial applications.…”

Section: Determination Of Melting Characteristicsmentioning

confidence: 99%

“…It can be seen that, as the B 2 O 3 content increased, T liq decreased continuously, while T sol decreased firstly, then increased slightly, and finally decreased. Melting characteristics (Ts, Th, and Tf) are closely related to the formation and melting of solid phases in the flux melting process [14]. Figure 8 shows the effects of B2O3 addition on the melting characteristics (Ts, Th, and Tf) of the CaO-SiO2-FeOx-MgO/B2O3 system.…”

Section: Effects Of B 2 O 3 On Phase and Mct Of Cao-sio 2 -Feo X -Mgomentioning

confidence: 99%

“…It was found that, with B2O3 content increasing, Ts, Th, and Tf decreased from 1400.60 °C to 1082.80 °C, 1414.60 °C to 1098.80 °C, and 1423.00 °C to 1131.00 °C, respectively. Compared with the melting characteristics of actual Melting characteristics (T s , T h , and T f ) are closely related to the formation and melting of solid phases in the flux melting process [14]. converter steel slag (Tf = 1420.00 °C, Th = 1414.00 °C, Ts = 1405.00 °C), the values of the CaO-SiO2-FeOx-MgO/B2O3 system with 5% B2O3 were found to be the closest to that of actual fluorinecontaining steel slag, indicating that this slag system could be used as a candidate for steelmaking applications.…”

Section: Effects Of B 2 O 3 On Phase and Mct Of Cao-sio 2 -Feo X -Mgomentioning

confidence: 99%

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Effects of B2O3 on Melting Characteristics and Temperature-Dependent Viscosity of High-Basicity CaO–SiO2–FeOx–MgO Slag

et al. 2020

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In order to reduce the amount of fluorite during the steelmaking process for environmental protection, it is essential to investigate the fluorine-free slag system. Thus, high-basicity CaO–SiO2–FeOx–MgO slag with B2O3 content from 0% to 15% was designed, and its melting characteristics and viscosity were investigated. The influence of B2O3 content on the phase diagram of the slag system was calculated using FactSage 7.3, and the break temperature was determined from the curves of temperature-dependent viscosity. The results show that, with the increase in B2O3 content, the melting characteristics of the CaO–SiO2–FeOx–MgO/B2O3 slag system, including liquidus temperature, flow temperature, softening temperature, and hemispheric temperature, all decreased; the main phase of the slag system transformed from Ca2SiO4 into borosilicate, and finally into borate; the viscous flow activation energy reduced from 690 kJ to 130 kJ; the break temperature reduced from 1590 °C to 1160 °C. Furthermore, the melting characteristics and the break temperature of the slag system with 5% and 8% B2O3 content were found to be the closest to the values of fluorine-containing steel slag.

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Effects of CaO/SiO2 Ratio and Na2O Content on Melting Properties and Viscosity of SiO2-CaO-Al2O3-B2O3-Na2O Mold Fluxes

Cited by 44 publications

References 36 publications

Viscosity and Structure of CaO–SiO₂–“FeO”–Al₂O₃–MgO System during Iron‐Extracting Process from Nickel Slag by Aluminum Dross. Part 1: Coupling Effect of “FeO” and Al₂O₃

Viscosity and Structure of CaO–SiO₂–“FeO”–Al₂O₃–MgO System during Iron‐Extracting Process from Nickel Slag by Aluminum Dross. Part 1: Coupling Effect of “FeO” and Al₂O₃

Viscosity and Structure of a CaO-SiO2-FeO-MgO System during a Modified Process from Nickel Slag by CaO

Effects of B2O3 on Melting Characteristics and Temperature-Dependent Viscosity of High-Basicity CaO–SiO2–FeOx–MgO Slag

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Effects of CaO/SiO2 Ratio and Na2O Content on Melting Properties and Viscosity of SiO2-CaO-Al2O3-B2O3-Na2O Mold Fluxes

Cited by 44 publications

References 36 publications

Viscosity and Structure of CaO–SiO2–“FeO”–Al2O3–MgO System during Iron‐Extracting Process from Nickel Slag by Aluminum Dross. Part 1: Coupling Effect of “FeO” and Al2O3

Viscosity and Structure of CaO–SiO2–“FeO”–Al2O3–MgO System during Iron‐Extracting Process from Nickel Slag by Aluminum Dross. Part 1: Coupling Effect of “FeO” and Al2O3

Viscosity and Structure of a CaO-SiO2-FeO-MgO System during a Modified Process from Nickel Slag by CaO

Effects of B2O3 on Melting Characteristics and Temperature-Dependent Viscosity of High-Basicity CaO–SiO2–FeOx–MgO Slag

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Product

Resources

About

Viscosity and Structure of CaO–SiO₂–“FeO”–Al₂O₃–MgO System during Iron‐Extracting Process from Nickel Slag by Aluminum Dross. Part 1: Coupling Effect of “FeO” and Al₂O₃

Viscosity and Structure of CaO–SiO₂–“FeO”–Al₂O₃–MgO System during Iron‐Extracting Process from Nickel Slag by Aluminum Dross. Part 1: Coupling Effect of “FeO” and Al₂O₃