scholarly journals Effect of MgO and K2O on High-Al Silicon–Manganese Alloy Slag Viscosity and Structure

Minerals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 810 ◽  
Author(s):  
Xiangdong Xing ◽  
Zhuogang Pang ◽  
Jianlu Zheng ◽  
Yueli Du ◽  
Shan Ren ◽  
...  
Keyword(s):  
Molten Slag ◽  
Photoelectron Spectra ◽  
Slag Viscosity ◽  
High Melting Point ◽  
Manganese Alloy ◽  
Flow Activation Energy ◽  
Slag Structure ◽  
Phase Spinel ◽  
Flow Activation ◽  
Manganese Slag

The viscosity, melting proprieties, and molten structure of the high-Al silicon–manganese slag of SiO2–CaO–25 mass% Al2O3–MgO–MnO–K2O system with a varying MgO and K2O content were studied. The results show that with the increase in MgO content from 4 to 10 mass%, the measured viscosity and flow activation energy decreases, but K2O has an effect on increasing those of slags. However, the melting temperature increases due to the formation of high-melting-point phase spinel. Meanwhile, Fourier transform infrared (FTIR) and X-ray photoelectron spectra (XPS) were conducted to understand the variation of slag structure. The O2− dissociates from MgO can interact with the O0 within Si–O or Al–O network structures, corresponding to the decrease in the trough depth of [SiO4] tetrahedral and [AlO4] tetrahedral. However, when K2O is added into the molten slag, the K+ can accelerate the formation of [AlO4] tetrahedra, resulting in the increase in O0 and O− and the polymerization of the structure.

Theory Calculation of Diffussion Coefficient Based on Molten Slag Structure

2011 ◽  
Vol 284-286 ◽  
pp. 411-415
Author(s):  
Yi Min ◽  
De Yong Wang ◽  
Mao Fa Jiang
Keyword(s):  
Diffusion Coefficient ◽  
Calculation Method ◽  
Diffusion Coefficients ◽  
Slag Composition ◽  
Molten Slag ◽  
Slag Viscosity ◽  
Modified Method ◽  
Slag Structure ◽  
Eyring Equation ◽  
Theory Calculation

The diffusion coefficients of slag constituents were calculated using Eyring equation. The Urbain slag viscosity calculation method was modified by improving the constiuents dividing method based on slag depolymerisation degree NBO/T calculation. the amphoteric oxides such as TiO2, Cr2O3, Fe2O3, B2O3 and Al2O3 were specifically dividied into glass former part and modifier part, and the diffusion dimension was calculated according to the value of NBO/T. The results of diffusion coefficients showed that, the modified method is more accurate than the Urbain method within the calculation conditions. Based on the modified diffusion coefficient calculation method, ladle slag composition was optimized to enhance the deoxidization rate.

scholarly journals Influence of Al2O3 Content on the Melting and Fluidity of Blast Furnace Type Slag with Low TiO2 Content

2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
Hao Liu ◽  
Yuelin Qin ◽  
Yanhua Yang ◽  
Qianying Zhang ◽  
Nengyun Deng
Keyword(s):  
Blast Furnace ◽  
Viscous Flow ◽  
Slag System ◽  
Al2o3 Content ◽  
Slag Viscosity ◽  
Flow Activation Energy ◽  
Flow Units ◽  
Precipitated Phase ◽  
Flow Activation ◽  
Furnace Slag

The increasing usage of iron ores with high Al2O3 content significantly increases the amount of Al2O3 in blast furnace slag and consequently affects its performance. This work uses slag sampled on site to study the effects of changes in Al2O3 content on the fluidity of the CaO–SiO2–Al2O3–MgO–TiO2 slag system that is characterized by high Al2O3 and low TiO2 contents, as well as on the phase transition law during the cooling process. Slag viscosity exhibits a rising trend with an increase in Al2O3 content, and Al2O3 in the tested slag is alkaline. The viscous flow activation energy of molten slag rises from 157 kJ/mol to 172 kJ/mol with an increase in Al2O3 content, and the viscous flow units in the slag become large and complicated. When slag is cooled, the main precipitated phase is melilitite. Spinel, perovskite, and olivine are also observed. The crystallization amount of the melilitite phase decreases constantly with an increase in Al2O3 content.

Non-Arrhenius Viscosity Models for Molten Silicate Slags with Constant Pre-Exponential Parameter: A Comparison to Arrhenius Model

2016 ◽  
Vol 35 (3) ◽  
pp. 261-267 ◽  
Author(s):  
Lei Gan ◽  
Chaobin Lai ◽  
Huihui Xiong
Keyword(s):  
Low Temperature ◽  
Molten Slag ◽  
Slag Viscosity ◽  
Arrhenius Model ◽  
Exponential Parameter ◽  
Viscosity Models ◽  
Lower Viscosity ◽  
Molten Silicate ◽  
Parameter Values

AbstractThe accuracies of molten slag viscosity fitting and low-temperature extrapolation were compared between four two-variable models: Arrhenius, Weymann–Frenkel (WF), and Vogel–Fulcher–Tammann (VFT) and Mauro, Yue, Ellison, Gupta and Allan (MYEGA) models with constant pre-exponential parameter, based on a molten slag viscosity database consisting of over 800 compositions and 5,000 measurements. It is found that over wide ranges of pre-exponential parameter, the VFT and MYEGA models have lower viscosity fitting errors and much higher low-temperature viscosity extrapolation accuracies than Arrhenius and WF models. The pre-exponential parameter values of –2.8 for VFT and –2.3 for MYEGA are recommended.

Molten Slag Structure and Diffusion Coefficients of Cr3+ and Si4+ during Micro-Carbon Cr-Fe Alloy Production

2011 ◽  
Vol 79 ◽  
pp. 77-82
Author(s):  
Yi Min ◽  
Jian Huang ◽  
Cheng Jun Liu ◽  
Mao Fa Jiang
Keyword(s):  
Diffusion Coefficient ◽  
Diffusion Coefficients ◽  
Molten Slag ◽  
Optimization Method ◽  
Structure Theory ◽  
Average Diffusion Coefficient ◽  
Slag Structure ◽  
Initial Stage ◽  
Silicate Structure ◽  
Average Diffusion

Based on the silicate structure theory, the molten slag structure and the existential state of and during micro-carbon Cr-Fe alloy production process were analysised, and then their diffusion coefficients were calculated. The results showed that, during the initial stage, the average diffusion coeffecient of and is close to the , the reaction process is controlled by the diffusion of () and corporately, during the later stage, the diffusion coefficient of is less than average diffusion coefficient of and , the controlling step is the diffusion of . According to the evolution of diffusion coefficient, molten slag composition optimization method was advised to increase the diffusion ability of and for enhancing the reaction efficiency and the recovery rate of chromium.

Rheological Study on of PBT with High Melt Flow Index

2012 ◽  
Vol 487 ◽  
pp. 644-648
Author(s):  
Yuan Liu ◽  
Lin Wang ◽  
Qing Yan Xu ◽  
Pei Jie Lin ◽  
Zhi Hong Guo ◽  
...  
Keyword(s):  
Activation Energy ◽  
Shear Rate ◽  
Apparent Viscosity ◽  
Melt Flow Index ◽  
Flow Index ◽  
Melt Flow ◽  
Flow Activation Energy ◽  
Nonwoven Fabrics ◽  
Flow Activation ◽  
High Flexibility

Melt-blown generated PBT nonwoven fabrics usually have small fibril diameter, high flexibility, well heat and oil resistance. Therefore, they would have promising application such as vehicle filtering media. The rheological behavior of PBT with High Melt Flow Index for Melt-blown is investigated in this paper. It is a direction of the technology design and fabrication parameters .The relation of apparent viscosity and shear rate is analyzed, as well as flow activation energy and Non-Newtonian indexes. The results suggest that PBT with High Melt Flow Index is Non-Newtonian fluid. Apparent viscosity and flow activation energy show gradually decrease with increasing shear rate, exhibiting typical shear-thinning behavior.

Rheological Behaviors of Graphene Oxide/Polyacrylonitrile Spinning Solutions

2017 ◽  
Vol 898 ◽  
pp. 2187-2196 ◽  
Author(s):  
Feng Mei Li ◽  
Ying Ying Zheng ◽  
Biao Wang
Keyword(s):  
Activation Energy ◽  
Graphene Oxide ◽  
Loss Factor ◽  
Viscosity Index ◽  
Structural Viscosity ◽  
Mechanical Loss ◽  
Flow Activation Energy ◽  
Rheological Behaviors ◽  
Flow Activation ◽  
Mechanical Loss Factor

The rheological behaviors of polyacrylonitrile (PAN) in NaSCN aqueous solutions containing different amount of Graphene oxide (GO) were investigated through both steady-state and dynamic rheological measurements. The parameters such as apparent viscosity (ηα), flow activation energy (Eη), structural viscosity index (Δη), storage modulus (G’), loss modulus (G’’) and mechanical loss factor (tanδ) were measured to illustrate the rheological behaviors of these solutions. The results showed that the apparent viscosity decreased with adding appropriate amount of GO, while the structural viscosity index, the flow activation energy and the mechanical loss factor of GO/PAN spinning solutions increased. Accordingly, a possible mechanism of GO effect on rheological behaviors of PAN solution was proposed in this work.

scholarly journals Effect of CaF2 on the Viscosity and Microstructure of CaO–SiO2–Al2O3 Based Continuous Casting Mold Flux

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 871
Author(s):  
Xingjuan Wang ◽  
Hebin Jin ◽  
Liguang Zhu ◽  
Ying Xu ◽  
Ran Liu ◽  
...  
Keyword(s):  
Continuous Casting ◽  
Mold Flux ◽  
Network Formation ◽  
Degree Of Polymerization ◽  
Slag Viscosity ◽  
Continuous Casting Mold ◽  
Flow Activation Energy ◽  
Casting Mold ◽  
Fluorine Ions ◽  
Caf2 Content

In this study, a CaO–SiO2–Al2O3-based continuous casting mold flux was designed using the FactSage thermodynamics software to determine the composition range of CaF2. The viscosity characteristics of the mold flux were determined using a rotating viscometer. The results show that the constant temperature viscosity at 1300 °C decreases gradually as CaF2 content is increased from 3% to 11% in the CaO–SiO2–Al2O3-based slag. Viscosity is reduced from 0.854 to 0.241 Pa·s, viscous the flow activation energy is reduced from 157.74 to 114.34 kJ·mol−1, and the break temperature is reduced from 1280 to 1180 °C. Furthermore, when the CaF2 content is increased from 3% to 11%, the number of nonbridging fluorine bonds (Al–F structure and Si–F structure) in the melt increases to 287, the number of bridging fluorine bonds (Al–F–Al structure, Si–F–Si structure, and Si–F–Si structure) is only 17, and the network rupture of fluorine ions in the system is larger than the network formation. Consequently, both the degree of polymerization and viscosity are reduced.

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