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1.
Tuo Wu Yanling Zhang Fang Yuan Zhuoqing An 《Metallurgical and Materials Transactions B》2018,49(4):1719-1731
The present study experimentally investigates the effect of Cr2O3 on the viscosity of molten slags. The viscosities of CaO-SiO2-10 pct Al2O3-Cr2O3 quaternary slags with two different binary basicities (R, basic slag with R = 1.2 and acidic slag with R = 0.8) were measured by the rotating cylindrical method from 1813 K to 1953 K (1540 °C to 1680 °C). The results showed that the viscosity of both types of slag decreased as the Cr2O3 content increased, but the viscosity of acidic slags exhibited a greater decrease. The slags showed good Newtonian behavior at such high temperatures. Cr2O3 could act as a network modifier to simplify the Si-O-Si tetrahedral structure, as verified by the Raman spectral analysis, which was consistent with the decreasing trend of viscosity. The activation energy of viscous flow decreased slightly with increasing Cr2O3, but increasing the basicity seemed to be more effective in decreasing the viscosity than adding Cr2O3. 相似文献
2.
The phase equilibria and liquidus temperatures in the ZnO-“FeO”-Al2O3-CaO-SiO2 system in equilibrium with metallic iron have been determined experimentally in the temperature range 1383 K to 1573 K (1150 °C
to 1300 °C). The experimental conditions were selected to characterize lead blast furnace and imperial smelting furnace slags.
The results are presented in a form of pseudoternary sections ZnO-“FeO”-(Al2O3 + CaO + SiO2) with fixed CaO/SiO2 and (CaO + SiO2)/Al2O3 ratios. It was found that wustite and spinel are the major primary phases in the composition range investigated. Effects
of Al2O3 concentration as well as the CaO/SiO2 ratio on the primary phase field, the liquidus temperature, and the partitioning of ZnO between liquid and solid phases have
been discussed for zinc-containing slags. 相似文献
3.
Kyoung-oh Jang Xiaodong Ma Jinming Zhu Haifa Xu Geoff Wang Baojun Zhao 《Metallurgical and Materials Transactions B》2017,48(3):1547-1560
The “FeO”-containing slags play an important role in the operation of an ironmaking blast furnace (BF), in particular the primary slags such as the system “FeO”-CaO-SiO2-Al2O3-2 mass pct MgO with CaO/SiO2 weight ratios of 1.3, 1.5, and 1.8 saturated with metallic iron. To investigate the characteristics of such a slag system and its behavior in BF, the phase equilibria and liquidus temperatures in the slag system have been experimentally determined using the high-temperature equilibration and quenching technique followed by an electron probe X-ray microanalysis (EPMA). Isotherms between 1553 K and 1603 K (1280 °C and 1330 °C) were determined in the primary phase fields of dicalcium silicate, melilite, spinel, and monoxide [(Mg,Fe2+)O]. Pseudo-ternary phase diagrams of (CaO + SiO2)-Al2O3-“FeO” with a fixed MgO concentration at 2 mass pct and at CaO/SiO2 ratios of 1.3, 1.5, and 1.8 have been discussed, respectively, simplifying the complexity of the slag system for easy understanding and applying in BF operation. It was found that the liquidus temperatures increase in melilite and spinel primary phase fields, but decrease in dicalcium silicate and monoxide primary phase fields with increasing Al2O3/(CaO + SiO2) ratio. In addition, the liquidus temperatures decrease with increasing “FeO” concentration in dicalcium silicate and melilite primary phase fields, while showing an increasing trend in the spinel and monoxide primary phase fields. The data resulted from this study can be used to improve and optimize currently available database of thermodynamic models used in FactSage. 相似文献
4.
Stanko Nikolic Peter C. Hayes Evgueni Jak 《Metallurgical and Materials Transactions B》2009,40(6):900-909
Calcium ferrite slags, which are represented by the “Cu2O”-FeO-Fe2O3-CaO system at copper saturation, have been applied successfully to existing copper-converting processes. Because of the industrial
importance of this system, the characterization of the effects of oxygen partial pressure and silica on the phase equilibria
is necessary to improve the control of process parameters, which include fluxing and operating temperatures. In the current
study, experimental methods, which use the equilibration/quenching/electron probe X-ray microanalysis (EPMA) techniques with
primary phase substrate support, were subsequently developed to incorporate fixed oxygen partial pressure experiments. Experiments
were carried out at 1200 °C and 1250 °C both with and without silica additions; both liquidus and solidus data were reported
for the primary phase field of spinel and dicalcium ferrite between the oxygen partial pressures of 10−5.0 and 10−6.5 atm. The analyzed compositions of the liquid and solid phases are used to construct the phase diagram of the pseudoternary
“Cu2O”-“Fe2O3”-CaO system in equilibrium with metallic copper at fixed oxygen partial pressures and with additions of silica. The maximum
solubility of silica within the liquid slag phase, prior to dicalcium silicate precipitation, was measured at specific conditions.
Two empirical equations used for the calculation of the copper oxide concentration in calcium ferrite slag are evaluated with
the new experimental data defined in the current study. 相似文献
5.
Baojun Zhao Peter C. Hayes Evgueni Jak 《Metallurgical and Materials Transactions B》2011,42(3):490-499
The phase equilibria in the ZnO-“FeO”-Al2O3-CaO-SiO2-MgO system have been determined experimentally in equilibrium with metallic iron. Synthetic slags were equilibrated at a
high temperature, quenched, and then the compositions of the phases in equilibrium were measured using electron probe X-ray
microanalysis. Pseudoternary sections of the form ZnO-“FeO”-(Al2O3 + CaO + SiO2) for CaO/SiO2 = 0.71, (CaO + SiO2)/Al2O3 = 5 and fixed MgO concentrations of 2, 4, and 6 wt pct have been constructed. Wustite (Fe2+,Mg,Zn)O and spinel (Fe2+,Mg,Zn)O·(Al,Fe3+)2O3 are the major primary phases in the temperature and composition ranges investigated. The liquidus temperatures are increased
by 140 K in the wustite primary phase field and by 70 K in the spinel primary phase field with the addition of 6 wt pct MgO
in the slag. The partitioning of MgO and ZnO between the solid and liquid phases has been discussed. 相似文献
6.
Baojun Zhao Peter C. Hayes Evgueni Jak 《Metallurgical and Materials Transactions B》2011,42(5):978-986
The phase equilibria in the ZnO-“FeO”-Al2O3-CaO-SiO2-S system have been determined experimentally in equilibrium with metallic iron. A pseudoternary section of the form ZnO-“FeO”-(Al2O3+CaO+SiO2) for CaO/SiO2 = 0.71 (weight), (CaO+SiO2)/Al2O3 = 5.0 (weight), and fixed 2.0 wt pct S concentration has been constructed. It was found that the addition of 2.0 wt pct S
to the liquid extends the spinel primary phase field significantly and decreases the size of the wustite primary phase field.
The liquidus temperature in the wustite primary phase field is decreased by approximately 80 K and the liquidus temperature
in the spinel primary phase field is decreased by approximately 10 K with addition of 2.0 wt pct S in the composition range
investigated. It was also found that iron-zinc sulfides are present in some samples in the spinel primary phase field, which
are matte appearing at low zinc concentrations and sphalerite (Zn,Fe)S at higher zinc concentrations. The presence of sulfur
in the slag has a minor effect on the partitioning of ZnO between the wustite and liquid phases but no effect on the partitioning
of ZnO between the spinel and liquid phases. 相似文献
7.
Hamed Abdeyazdan Brian J. Monaghan Raymond J. Longbottom M. Akbar Rhamdhani Neslihan Dogan Michael W. Chapman 《Metallurgical and Materials Transactions B》2017,48(4):1970-1980
Interfacial phenomenon is critical in metal processing and refining. While it is known to be important, there are little data available for key oxide systems in the literature. In this study, the interfacial tension (σ LS) of liquid slag on solid oxides (alumina, spinel, and calcium aluminate), for a range of slags in the CaO-Al2O3-SiO2-(MgO) system at 1773 K (1500 °C), has been evaluated. The results show that basic ladle-type slags exhibit lower σ LS with oxide phases examined compared to that of acid tundish-type slags. Also, within the slag types (acid and base), σ LS was observed to decrease with increasing slag basicity. A correlation between σ LS and slag structure was observed, i.e., σ LS was found to decrease linearly with increasing of slag optical basicity (Λ) and decrease logarithmically with decreasing of slag viscosity from acid to base slags. This indicated a higher σ LS as the ions in the slag become larger and more complex. Through a work of adhesion (W) analysis, it was shown that basic ladle slags with lower σ LS result in a greater W, i.e., form a stronger bond with the solid oxide phases examined. This indicates that all other factors being equal, the efficiency of inclusion removal from steel of inclusions of similar phase to these solid oxides would be greater. 相似文献
8.
9.
Stanko Nikolic Peter C. Hayes Evgueni Jak 《Metallurgical and Materials Transactions B》2009,40(6):910
Calcium ferrite slags, which are represented by the “Cu2O”-FeO-Fe2O3-CaO system at copper saturation, have been applied successfully to existing copper-converting processes. Because of the industrial importance of this system, the characterization of the effects of oxygen partial pressure and silica on the phase equilibria is necessary to improve the control of process parameters, which include fluxing and operating temperatures. In the current study, experimental methods, which use the equilibration/quenching/electron probe X-ray microanalysis (EPMA) techniques with primary phase substrate support, were subsequently developed to incorporate fixed oxygen partial pressure experiments. Experiments were carried out at 1200 °C and 1250 °C both with and without silica additions; both liquidus and solidus data were reported for the primary phase field of spinel and dicalcium ferrite between the oxygen partial pressures of 10?5.0 and 10?6.5 atm. The analyzed compositions of the liquid and solid phases are used to construct the phase diagram of the pseudoternary “Cu2O”-“Fe2O3”-CaO system in equilibrium with metallic copper at fixed oxygen partial pressures and with additions of silica. The maximum solubility of silica within the liquid slag phase, prior to dicalcium silicate precipitation, was measured at specific conditions. Two empirical equations used for the calculation of the copper oxide concentration in calcium ferrite slag are evaluated with the new experimental data defined in the current study. 相似文献
10.
V. V. Popov A. A. Yastrebtsev I. S. Smirnov I. S. Monakhov E. G. Novoselova N. A. Tsarenko A. L. Udovskii 《Russian Metallurgy (Metally)》2016,2016(9):869-874
The calculated and experimental vertical ZrO2–Y2O3 sections of the Zr–Y–O system are compared to find the region of a stable fluorite structure of yttrium-stabilized zirconia (YSZ). X-ray diffraction (XRD) and Raman scattering are used to study the crystal and local structures of mixed oxide 0.82ZrO2 · 0.18Y2O3 (18YSZ) powders prepared by isothermal annealing of a precursor precipitated from a salt solution. The formation of a fluorite-type fcc structure (space group \(Fm\overline 3 m\)) in the powders is detected by XRD. Raman scattering study of the local structure of the cubic 18YSZ powders revealed traces of the tetragonal phase in them. 相似文献
11.
In thermodynamic modeling of the desulfurization of steel by CaO–SiO2–MgO–Al2O3–B2O3 slag on the basis of HSC 6.12 Chemistry software (Outokumpu), the influence of the temperature (1500–1700°C), the slag basicity (2–5), and the B2O3 content (1–4%)1 on the desulfurization is analyzed. It is found that the sulfur content is reduced with increase in the temperature from 1500 to 1700°C, within the given range of slag basicity. At 1600°C, the sulfur content in the metal is 0.0052% for slag of basicity 2; at 1650°C, by contrast, its content is 0.0048%. Increase in slag basicity from 2 to 5 improves the desulfurization, which increases from 80.7 to 98.7% at 1600°C. If the B2O3 content in the slag rises, desulfurization is impaired. At 1600°C, the sulfur content in the metal may be reduced to 0.0052 and 0.0098% when using slag of basicity 2 with 1 and 4% B2O3, respectively; in the same conditions but with slag of basicity 5, the corresponding values are 0.00036 and 0.00088%, respectively. Note that desulfurization is better for slag without B2O3. According to thermodynamic modeling, metal with 0.0039 and 0.00019% S is obtained at 1600°C when using slag of basicity 2 and 5, respectively, that contains no B2O3. The results obtained by thermodynamic modeling for the desulfurization of metal by CaO–SiO2–MgO–Al2O3–B2O3 slag of basicity 2–5 in the range 1500–1700°C are consistent with experimental data and may be used in improving the desulfurization of steel by slag that contains boron. 相似文献
12.
Baojun Zhao Peter C. Hayes Evgueni Jak 《Metallurgical and Materials Transactions B》2010,41(2):374-385
The phase equilibria and the liquidus temperatures in the system ZnO-“FeO”-Al2O3-CaO-SiO2 have been determined experimentally in equilibrium with metallic iron. Specifically, the effects of Al2O3 concentrations in Imperial Smelting Furnace slags are identified, and the results are presented in the form of pseudo-ternary
sections ZnO-“FeO”-(Al2O3 + CaO + SiO2) in which CaO/SiO2 = 0.93 and (CaO + SiO2)/Al2O3 = 5.0 and 3.5, respectively. It was found that, in the presence of Al2O3, the spinel phase is formed, the spinel primary phase field expands, and the wustite and melilite primary phase fields are
reduced in size with an increasing Al2O3 concentration. The implications of the findings to industrial practice are discussed. 相似文献
13.
Baojun Zhao Peter C. Hayes Evgueni Jak 《Metallurgical and Materials Transactions B》2010,41(2):386-395
The phase equilibria and the liquidus temperatures in the system ZnO-“FeO”-Al2O3-CaO-SiO2 have been determined experimentally in equilibrium with metallic iron. Specifically, the effects of Al2O3 concentrations in Imperial Smelting Furnace slags are identified, and the results are presented in the form of pseudo-ternary sections ZnO-“FeO”-(Al2O3 + CaO + SiO2) in which CaO/SiO2 = 0.93 and (CaO + SiO2)/Al2O3 = 5.0 and 3.5, respectively. It was found that, in the presence of Al2O3, the spinel phase is formed, the spinel primary phase field expands, and the wustite and melilite primary phase fields are reduced in size with an increasing Al2O3 concentration. The implications of the findings to industrial practice are discussed. 相似文献
14.
The viscous behavior of the CaO-SiO2-12 mass pct Na2O based slag system with various concentrations of NaF has been studied using the rotating spindle method. NaF additions decreased
the viscosity by interacting with bridged oxygens in the complex silicates and depolymerizing the network structure of the
molten slag. NaF was particularly effective at lowering the viscosity in small amounts, but beyond 8 mass pct NaF, the effect
was not as pronounced. A comparison between additions of NaF and CaF2 revealed NaF to be more effective at decreasing the viscosity for 1523 K and 1573 K (1250 °C and 1300 °C). From the slopes
of the Arrhenius relationship for viscosity, the activation energy of viscous flow was found to be between 128 kJ/mol to 115 kJ/mol,
which were lower than the values for the same amount of CaF2 additions. Both a temperature effect and a compositional effect on the molten slag structure and subsequently the viscous
behavior were observed. The Fourier transformed infrared (FTIR) spectra taken for the CaO-SiO2-12 mass pct Na2O-8 mass pct NaF slag samples quenched from 1623 K to 1773 K (1350 °C to 1500 °C) revealed that the temperature effect on
the viscosity was observed at temperatures below 1673 K (1400 °C). 相似文献
15.
16.
17.
Chunyang Liu Motoki Yagi Xu Gao Sun-joong Kim Fuxiang Huang Shigeru Ueda Shin-ya Kitamura 《Metallurgical and Materials Transactions B》2018,49(1):113-122
During ladle furnace refining, initial Al2O3 inclusions generally transform into MgO·Al2O3 spinel inclusions; these generated spinel inclusions consequently deteriorate the product quality. In this study, the transformation from Al2O3 to MgO·Al2O3 was investigated by immersing an Al2O3 rod into molten steel, which was in equilibrium with both MgO and MgO·Al2O3 spinel-saturated slag. A spinel layer, with a thickness of 4 μm, was generated on the Al2O3 rod surface just 10 s after its immersion at 1873 K (1600 °C). The thickness of the formed spinel layer increased with the immersion period and temperature. Moreover, the MgO content of the generated spinel layer also increased with the immersion period. In this study, the chemical reaction rate at 1873 K (1600 °C) was assumed to be sufficiently high, and only diffusion was considered as a rate-controlling step for this transformation. By evaluating the activation energy, MgO diffusion in the generated spinel layer was found to be the rate-controlling step. In addition, this estimation was confirmed by observing the Mg and Al concentration gradients in the generated spinel layer. The results of this study suggest that the MgO diffusion in the spinel inclusions plays a substantial role with regard to their formation kinetics. 相似文献
18.
Y. Kaida M. Hasegawa M. Iwase Y. Kikuchi K. Wakimoto 《Metallurgical and Materials Transactions B》2005,36(1):43-51
An experimental technique was applied for simultaneous determinations of the activities of P2O5 and FexO in slags. With this technique, phosphorus-containing liquid copper was heated inside an iron crucible at temperatures below
1600 K. When copper is melted, the iron crucible dissolves into liquid copper, to a small extent, to form ternary {Cu-Fe-P}
liquid alloy, while 〈Cu-Fe-P〉 solid solutions are formed on the inner wall of the iron crucible. Slags containing tri-calcium
phosphate were then brought into equilibrium with {Cu-Fe-P} liquid alloy. By measuring the equilibrium oxygen partial pressures
with the aid of a zirconia electrolyte cell, activities of P2O5 and FexO were obtainable. Between 1553 and 1593 K, the P2O5 activities could be expressed as
The activities of P2O5 and FexO thus obtained were thermodynamically consistent with those deduced from the phase diagram. 相似文献
19.
A. A. Babenko S. A. Istomin V. I. Zhuchkov A. V. Sychev V. V. Ryabov A. G. Upolovnikova 《Russian Metallurgy (Metally)》2017,2017(5):372-375
The simplex lattice method of planning experiments is used to study the viscosities of CaO–SiO2–Al2O3–8% MgO–4% B2O3 slags in a wide chemical composition range. For each viscosity, we developed an adequate mathematical model in the form of a reduced third-order polynomial. The results of mathematical simulation are presented in composition–viscosity diagrams. Composition regions with a high fluidity of slags, the viscosities of which are 0.8–1.2 Pa s in the temperature range 1500–1600°C, are indicated in the diagrams. 相似文献
20.
Rong Cheng Jiongming Zhang Bo Wang 《Transactions of the Indian Institute of Metals》2018,71(3):705-713
The present study was aimed at exploring the influence of compositions on the deformation behavior of inclusion system CaO–Al2O3–SiO2, during hot rolling processes. The plastic deformations of four inclusions with different compositions, at different rolling temperatures (800, 850, 900, 982 and 1100 °C), were simulated using a finite element model. The equivalent plastic strain distributions and the shapes of the inclusions after rolling were obtained via the model. The influences of rolling temperature, flow stresses of inclusions and matrix, reduction, etc., on the void length and the deformation degree of inclusions were analyzed. The critical temperatures of the four inclusions during hot rolling were different. No voids occurred above the critical temperature. Voids only occurred along the length direction, but not the width and thickness directions, below the critical temperature. Low rolling temperatures led to long void length and small deformation of inclusions. The inclusion with high SiO2 content had a high critical temperature and a high risk of void formation. Results generated by the experiment on deformation behaviors of inclusions with different SiO2 content, were in good agreement with the simulated results. 相似文献