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.

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 Vaporization of Vanadium Pentoxide from CaO-SiO2-VOx Slags During Alumina Dissolution

2021 ◽  
Author(s):  
Tetiana Shyrokykh ◽  
Xingwen Wei ◽  
Seshadri Seetharaman ◽  
Olena Volkova
Keyword(s):  
Surface Tension ◽  
Gas Phase ◽  
Vanadium Pentoxide ◽  
Molten Slag ◽  
Slag Viscosity ◽  
Crucible Material ◽  
Gas Treatment ◽  
Treatment Regimens ◽  
High Vapor ◽  
Alumina Dissolution

AbstractThe vaporization of vanadium pentoxide from CaO-SiO2-VOx ternary slags using different gas treatment regimens and parallel vacuum gas extirpation to treat V-bearing slags at 1873 K has been developed in the present study. The novelty of the present study is to monitor the effect of parallel alumina dissolution on the vaporization phenomenon. Vanadium pentoxide has high vapor pressure at the temperatures over 1500 K. When CaO-SiO2-VOx ternary slags, kept in dense alumina crucibles, are injected with oxygen, V2O5 gas bubbles are formed which are forced out by using vacuum extirpation. The vanadium pentoxide could be then collected in the exhaust gases. The mechanism of the process phenomenon is described as the formation of V2O5 gas phase resulting from the oxidation of the lower-valent oxides present in the slag. This gas phase would form microbubbles in the molten slag bulk phase due to low surface tension between the gas phase and the slag, thereby increasing the contact surface. At the same time, the crucible material would dissolve in the slag causing an increase in the slag viscosity. Due to the high slag viscosity of the bulk slag, these microbubbles formed would have difficulty in coalescing and reaching the slag surface. The escaping of the bubbles into the gas phase is enabled by the vacuum extirpation.

Properties of OQPaP Bleached Pulp of Pinus kesiya and Dendrocalamus giganteus Munro Made by Low-Temperature Kraft Pulping

2014 ◽  
Vol 900 ◽  
pp. 285-288
Author(s):  
Qi Xing Liu ◽  
Yang Chen ◽  
Jie He ◽  
Xin Gao
Keyword(s):  
Low Temperature ◽  
Kraft Pulp ◽  
Kraft Pulping ◽  
Paper Properties ◽  
Bleached Pulp ◽  
Pinus Kesiya ◽  
Lower Viscosity ◽  
Dendrocalamus Giganteus

In this paper, the low-temperature (the maximum pulping temperature was less than 150°C) and conventional (the maximum pulping temperature was 165°C) kraft pulp of pinus kesiya and Dendrocalamus giganteus Munro were bleached by OQPaP. Then bleaching properties and paper properties of two kinds of bleached pulp were compared and evaluated respectively. The results showed that the strength indexes of the kraft pulp at low temperature were significantly higher than those of conventional pulp with lower viscosity.

Spinning properties of slag fiber according to viscosity model

2019 ◽  
Vol 33 (14n15) ◽  
pp. 1940027
Author(s):  
Chang Wook Park ◽  
Sung Won Yoon ◽  
Soo Jeong Park ◽  
Yun Hae Kim
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Carbon Fibers ◽  
Basalt Fiber ◽  
Process Conditions ◽  
Steelmaking Process ◽  
Viscosity Models ◽  
Glass Carbon ◽  
Key Variables ◽  
Selection Of

Slag means residues that occur during the steelmaking process. Measuring the high temperature viscosity of the slag is difficult and high cost. So, viscosity models can be used to predict the trends in viscosity as a function of the key variables, and so assist in the selection of process conditions and the optimization of the performance of slag fibers. Slag fibers with compositions similar to glass/carbon fibers are also expected to be suitable for spinning at a log viscosity value of 2.8–3. The fiberizing temperature of glass fiber is more than [Formula: see text] and the fiberizing temperature of basalt fiber is more than [Formula: see text], while the slag fiber can be spun at a low temperature.

scholarly journals Truncating the exponential with a uniform distribution

2021 ◽  
Author(s):  
Rafael Weißbach ◽  
Dominik Wied
Keyword(s):  
Uniform Distribution ◽  
Standard Error ◽  
Point Processes ◽  
Computational Effort ◽  
Point Estimation ◽  
Simple Random Sample ◽  
Time Interval ◽  
Exponential Parameter ◽  
Root Finding ◽  
Parameter Values

AbstractFor a sample of Exponentially distributed durations we aim at point estimation and a confidence interval for its parameter. A duration is only observed if it has ended within a certain time interval, determined by a Uniform distribution. Hence, the data is a truncated empirical process that we can approximate by a Poisson process when only a small portion of the sample is observed, as is the case for our applications. We derive the likelihood from standard arguments for point processes, acknowledging the size of the latent sample as the second parameter, and derive the maximum likelihood estimator for both. Consistency and asymptotic normality of the estimator for the Exponential parameter are derived from standard results on M-estimation. We compare the design with a simple random sample assumption for the observed durations. Theoretically, the derivative of the log-likelihood is less steep in the truncation-design for small parameter values, indicating a larger computational effort for root finding and a larger standard error. In applications from the social and economic sciences and in simulations, we indeed, find a moderately increased standard error when acknowledging truncation.

scholarly journals SOLUBILITY AND MISCIBILITY OF REFRIGERANTS R407C AND R410A WITH SYNTHETIC COMPRESSOR OILS

2016 ◽  
Vol 52 (3) ◽  
Author(s):  
V. Z. Geller ◽  
N. I. Lapardin
Keyword(s):  
Low Temperature ◽  
Visual Observation ◽  
Solution Temperature ◽  
Miscibility Gap ◽  
Critical Solution Temperature ◽  
Temperature Range ◽  
Lower Viscosity ◽  
Mass Fractions ◽  
Viscosity Grade ◽  
Simple Equations

In this paper, solubility and low temperature miscibility of refrigerants R407C and R410A in four different commercial Polyolester (POE) lubricants, produced by the same company but with different ISO standard viscosity grade, are measured with the aim to evaluate the possible correlation of solubility and miscibility with standard viscosity of the lubricant. Vapor pressure (solubility) is measured using calibrated, constant volume cells at oil mass fractions 30, 50, 70, 80, and 90% over a temperature range from -20 to 100 °C, and pressures up to 5 MPa. The measurements of low temperature miscibility limit (lower critical solution temperature LCST) were made using high-pressure sapphire cell. LCST was directly obtained by visual observation of a «milky haze» followed by a phase separation. Miscibility data were obtained at oil mass fractions from 5 to 50% over a temperature range from -60 to 0 °C. A set of simple equations was derived to describe the experimental results. Analysis of the obtained results showed that the solubility of refrigerant/lubricant mixtures depends weakly on the viscosity grade of the oil. At the same time, the miscibility gap (LCST) differ much bigger for various refrigerant/lubricant mixtures. The lower viscosity grade of the oil, the lower LCST of the refrigerant/lubricant mixture. LCSTs for the mixtures of R407C with the lubricants with the viscosity grades 32 and 220 differ by 30-45 °С.

Low Temperature Dynamic Properties of Bitumin-Rubber Mixtures

1980 ◽  
Vol 53 (1) ◽  
pp. 88-106 ◽  
Author(s):  
J. Shim-Ton ◽  
K. A. Kennedy ◽  
M. R. Piggott ◽  
R. T. Woodhams
Keyword(s):  
Low Temperature ◽  
Calcium Hydroxide ◽  
Dynamic Properties ◽  
Rubber Mixture ◽  
Waste Products ◽  
Lower Viscosity ◽  
Elastomeric Materials ◽  
Second Order Transition ◽  
Thickening Behavior ◽  
Temperature Dynamic

Abstract The influence of four different elastomeric materials on the low temperature dynamic properties of bitumen was determined using a Rheovibron Viscoelastometer. The four elastomeric materials included two waste products and two liquid rubbers : powdered vulcanized tire reclaim rubber, precipitated waste SBR latex from an effluent recovery system, liquid carboxy-terminated butadiene-co-acrylonitrile polymer (Goodrich CTBN), and liquid polybutadiene with terminal allylic bromine substituents (Polysar Liquid RTV Polymer). The results of the evaluation indicate that liquid polybutadiene is the most efficient low temperature flexibilizer, as might be expected from its low second order transition temperature (−85°C). A comparison of the penetration of the rubber-bitumen mixtures with the Brookfield viscosity reveals that the addition of rubber markedly reduces the temperature susceptibility. Attempts were also made to follow the thickening behavior of bitumen/ CTBN rubber mixtures after the addition of calcium hydroxide. The large increase in viscosity immediately following the addition of calcium hydroxide was followed by a gradual return to a slightly lower viscosity than the original bitumen-rubber mixture. The implications of the low temperature dynamic transitions, viscosity behavior, penetration values and thickening behavior of bitumen/rubber mixtures with respect to road performance are discussed.

Effect of slag composition on desulfurization during recycling rejected electrolytic manganese metal by electroslag remelting

2021 ◽  
Vol 118 (2) ◽  
pp. 206
Author(s):  
Yu Liu ◽  
Guangqiang Li ◽  
Qiang Wang ◽  
Ru Lu ◽  
Xijie Wang ◽  
...  
Keyword(s):  
Sulfur Content ◽  
Distribution Ratio ◽  
Slag Composition ◽  
Molten Slag ◽  
Electroslag Remelting ◽  
Metal Scrap ◽  
Sulfur Distribution ◽  
Lower Viscosity ◽  
Electrolytic Manganese ◽  
Sulfur Distribution Ratio

To reduce the Mn vaporization during recycling rejected electrolytic manganese metal by electroslag remelting, it is proposed to reduce the temperature of molten slag pool, but which leads to the degradation of slag desulfurization. The desulfurization by interaction between CaF2–CaO–Al2O3–Na2O slag and rejected electrolytic manganese metal scrap was studied from the view of thermodynamics in this study. The results show that sulfur distribution ratio decreases with increase of CaF2 content, and increases with the increase of Na2O content and temperature. Na2O increases sulfur distribution ratio of slag by increasing CaO activity. Na2O addition in CaF2–CaO–Al2O3–Na2O slag can enhance desulfurization ability of slag due to the larger sulfur distribution ratio and lower viscosity. Thus, sulfur content in test of slag T3 bearing 45.8 wt% CaF2-23.2 wt% CaO-22.7 wt% Al2O3-8.3 wt% Na2O is much lower than that of slag without Na2O, implying that 45.8 wt% CaF2-23.2 wt% CaO-22.7 wt% Al2O3-8.3 wt%Na2O slag is the promising slag for recycling rejected electrolytic manganese metal by ESR.

Effect of SiO2 containing slag for electroslag remelting on inclusion modification of 42CrMo steel

2019 ◽  
Vol 116 (6) ◽  
pp. 627 ◽  
Author(s):  
Yu Liu ◽  
Zhao Zhang ◽  
Guangqiang Li ◽  
Yang Wu ◽  
Xijie Wang ◽  
...  
Keyword(s):  
Slag Composition ◽  
Molten Slag ◽  
Oxide Inclusion ◽  
Electroslag Remelting ◽  
Slag Viscosity ◽  
Oxide Inclusions ◽  
Al Content ◽  
42Crmo Steel ◽  
Increasing Trend ◽  
Inclusion Modification

Five heats were carried out to study the effects of SiO2 containing slag for electroslag remelting (ESR) on inclusion characteristics of 42CrMo steel. Fluoride vaporization at elevated temperature from slags was also explored by thermogravimetric analysis. The results show that fluoride vaporization is dominated by slag viscosity and component activities in the melt. Slag composition has an important effect on the composition of the oxide inclusion. For 70 wt% CaF2–30 wt% Al2O3 slag, the compositions of oxide inclusions in remelted steel show no obvious differences compared with the virgin steel. Whereas, SiO2 content in oxide inclusions of steel processed by slag bearing SiO2 show an increasing trend with increase of SiO2 content in 50 wt% CaF2–CaO–SiO2 slag, and the MgO · Al2O3 inclusions are modified to (Al,Ca,Mg,Si)O inclusions with low melting temperature. Al2O3 contents in oxide inclusions are also closely related to the Al2O3 concentration in the molten slag, which increase with the addition of Al2O3 in slag bearing SiO2. In testing various slags, the incorporation of slag T2 with 50 wt% CaF2–30 wt% CaO–20 wt% SiO2 shows the highest cleanliness in remelted steel. This implies that slag T2 can be a promising slag for ESR process of alloy steel requiring Al content refinement due to less fluoride vaporization from slag and better inclusions modification.

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