Vanadium oxide solubility in CaO–SiO2–VOXsystem

Åström, Elin; Björkvall, Johan; Björkman, Bo; Hallberg, Dan

doi:10.1080/03019233.2016.1155841

Cited by 6 publications

(6 citation statements)

References 16 publications

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“…E. Åström et al determined the solubility limit of vanadium oxide in the CaO–SiO 2 –VO x system at 1873 K under the atmosphere of 97.7 volume pct CO and 2.3 volume pct CO 2 . They reported that the solubility limit varied in the range of 14 mass pct to 18 mass pct V 2 O 3 , which is comparable with the present results.…”

Section: Discussionmentioning

confidence: 99%

“…The slags were equilibrated with a gas mixture of CO, CO 2 and Ar in Pt crucible, and the activity coefficient of V 2 O 3 was estimated also by assuming the existence of vanadium as V 3+ . In addition, the solubility of vanadium oxide in the CaO–SiO 2 –VO x system and in the CaO(30 and 35 mass %)‐Al 2 O 3 –SiO 2 –VO x system at 1873 K and the oxygen partial pressure of 10 −10 atm have been determined recently.…”

Section: Introductionmentioning

confidence: 99%

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Thermodynamics of the CaO–SiO₂–VO_x system at 1873 K under the oxygen partial pressure of 6.9×10⁻¹¹ atm

et al. 2017

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Based on the phase equilibria of the CaO-SiO 2 -VO x system determined experimentally at 1873 K and the oxygen partial pressure of 6.9910 À11 atm, the isothermal section diagram of the system was constructed. Aside from the simple oxides SiO 2 and V 2 O 3 , three complex crystal phases CaV 2 O 4 , Ca 2 SiO 4 dissolving V 2 O 3 , and CaVO 3 dissolving SiO 2 were found in the present investigated composition range. The solubility of V 2 O 3 in Ca 2 SiO 4 phase can reach 5 mass %, and the CaVO 3 phase dissolves about 5% mass SiO 2 . Furthermore, the thermodynamic activities of VO x and SiO 2 in the determined single liquid region were measured by equilibrating the melts with liquid copper. The activity coefficient of SiO 2 decreases linearly with the increase in the basicity of the melts and is almost irrelevant to the total content of vanadium oxides. The activities of vanadium oxides increase slightly with the increase in the basicity but are mainly determined by the total content of vanadium oxides in the melts. With the increase in the basicity, the activity coefficient of VO 1.5 increases almost linearly, whereas those of VO 2 and VO 2.5 decrease gradually.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Thermodynamics of the CaO–SiO₂–VO_x system at 1873 K under the oxygen partial pressure of 6.9×10⁻¹¹ atm

et al. 2017

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“…Relating to the preparation of some vanadium compounds and the pyrometallurgical extraction process of vanadium, CaO–SiO 2 –VO x is one of the most basic important systems . Hence, the phase equilibria and thermodynamic properties of this system are desirable in controlling the processes …”

Section: Introductionmentioning

confidence: 99%

“…Comparatively, less attention was paid to the effects of oxygen partial pressure. For example, E. Astrom et al determined the effect of the ratio of CaO/SiO 2 on the saturation solubility of V 2 O 3 in the melts of CaO–SiO 2 –VO x system at 1873 K under the oxygen partial pressure of 10 −10 atm, but no investigations about the effect of oxygen partial pressure on the solubility of V 2 O 3 were reported. Tian et al measured the activity of VO in the CaO–SiO 2 –VO melts at 1773 K under the oxygen partial pressure of approximately 10 −16 atm.…”

Section: Introductionmentioning

confidence: 99%

“…[11][12][13][14] Hence, the phase equilibria and thermodynamic properties of this system are desirable in controlling the processes. 15,16 Since vanadium is a transition element, vanadium oxide has different oxidation states. Consequently, the oxygen content in the CaO-SiO 2 -VO x system, as well as the valence of vanadium, will not be a constant.…”

Section: Introductionmentioning

confidence: 99%

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Effects of oxygen partial pressure on the thermodynamics of CaO–SiO₂–VO_x system at 1873 K

et al. 2019

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In this study, two aspects concerning with the thermodynamics of CaO–SiO2–VOx system were investigated. One aspect is about the effects of oxygen partial pressure on the phase relationships in CaO–SiO2–VOx system at 1873 K, and the other is the measurement of the standard Gibbs energy of formation of the vanadium compounds. In the first aspect, the phase relationships in CaO–SiO2–VOx system at 1873 K under oxygen partial pressure of 1.7 × 10−9 atm were determined, and the isothermal section diagram was constructed. Furthermore, by comparing this diagram with that under 6.9 × 10−11 atm, the effects caused by oxygen partial pressure on this system were elucidated. With the increase in oxygen partial pressure, the compound CaV2O4 that exists stably under 6.9 × 10−11 atm is oxidized to V2O3 and CaVO3. The solubility limit of V2O3 in liquid phase also increases remarkably, which results in the enlargement of the single liquid area. In the second aspect, the standard Gibbs energy of formation of CaV2O4, CaVO3, V2O3, and Ca2Si1−δVδO4 (0 < δ < 0.1) at 1873 K were measured. The determined values for CaV2O4 and CaVO3 are −1 259 468.9 ± 5090.5 J/mol and −963 479.8 ± 3298.6 J/mol, respectively. Then, the limit of oxygen partial pressure for CaV2O4 existing stably at 1873 K is determined to be 4.4 × 10−10 atm.

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Effect of Reduction Degree on Characteristics of Slag Formed by Melting Hydrogen‐Reduced DRI and Partitions of P and V between Slag and Metal

Vickerfält

Martinsson

Sichen

2020

steel research int.

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Self‐fluxing hematite pellets are reduced by hydrogen to different degrees. The reduced pellets are melted in closed MgO crucibles at 1873 K to study the effect of reduction degree on the characteristics of slag formed. The results reveal that the phosphorus content in the metallic phase can be brought down to 130 ppm merely by the self‐fluxing slag, even though the slag weighs only about 8% of the metal. It shows a great potential in reducing the amount of slag formers in the steelmaking process. The slag compositions obtained by melting the reduced pellets are used to prepare small synthetic slag samples for identifying the phases after melting. The use of the small samples is to ensure efficient quenching. Microscopic examination reveals that all the self‐fluxing slags contain mainly three phases, namely, magnesiowüstite, spinel, and a liquid phase. Most of vanadium is found to be in the spinel and magnesiowüstite phases. The liquid phase only contains 1–2 wt% V2O3. Decreased FeO content of the slag increases the vanadium oxide contents in the spinel and magnesiowüstite phases. The fact that vanadium concentrates in the solid oxide phases provides essential information for sustainable extraction of vanadium from the steelmaking slag.

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Vanadium oxide solubility in CaO–SiO₂–VO_Xsystem

Cited by 6 publications

References 16 publications

Thermodynamics of the CaO–SiO₂–VO_x system at 1873 K under the oxygen partial pressure of 6.9×10⁻¹¹ atm

Thermodynamics of the CaO–SiO₂–VO_x system at 1873 K under the oxygen partial pressure of 6.9×10⁻¹¹ atm

Effects of oxygen partial pressure on the thermodynamics of CaO–SiO₂–VO_x system at 1873 K

Effect of Reduction Degree on Characteristics of Slag Formed by Melting Hydrogen‐Reduced DRI and Partitions of P and V between Slag and Metal

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Vanadium oxide solubility in CaO–SiO2–VOXsystem

Cited by 6 publications

References 16 publications

Thermodynamics of the CaO–SiO2–VOx system at 1873 K under the oxygen partial pressure of 6.9×10−11 atm

Thermodynamics of the CaO–SiO2–VOx system at 1873 K under the oxygen partial pressure of 6.9×10−11 atm

Effects of oxygen partial pressure on the thermodynamics of CaO–SiO2–VOx system at 1873 K

Effect of Reduction Degree on Characteristics of Slag Formed by Melting Hydrogen‐Reduced DRI and Partitions of P and V between Slag and Metal

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Vanadium oxide solubility in CaO–SiO₂–VO_Xsystem

Thermodynamics of the CaO–SiO₂–VO_x system at 1873 K under the oxygen partial pressure of 6.9×10⁻¹¹ atm

Thermodynamics of the CaO–SiO₂–VO_x system at 1873 K under the oxygen partial pressure of 6.9×10⁻¹¹ atm

Effects of oxygen partial pressure on the thermodynamics of CaO–SiO₂–VO_x system at 1873 K