Equilibrium slag losses in ferrovanadium production

Vermaak, M.K.G.; Pistorius, Petrus Christiaan

doi:10.1007/s11663-000-0084-1

Cited by 12 publications

(19 citation statements)

References 2 publications

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“…Vermaak and Pistorius reported that slag basicity affects the amount of dissolved vanadium in the oxide phases. Figure shows EDS analysis results of vanadium distribution in equilibrium phases in samples treated in air.…”

Section: Discussionmentioning

confidence: 99%

Experimental Study of Phase Equilibria in CaO–SiO₂–MgO–Al₂O₃–V₂O₃ Slags

Yang

Teng

Seetharaman

2014

steel research int.

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Thermodynamic data with regard to slags containing vanadium oxide are scarce and scattered. In the present study, the classic gas-slag equilibrium technique has been adopted to investigate the phase relationships in the CaO-SiO 2 -MgO-Al 2 O 3 -V 2 O 3 slags. The phase equilibria in the slag systems in the temperature range of 1773-1823 K (1500-1550 8C) at oxygen partial pressures of 10 À5 Pa and 0.21 Â 10 5 Pa were characterized. CaVO 3 was precipitated in samples with basicity 1.5 and 1.8 treated in air at 1773 K (1550 8C) while all vanadium was dissolved in equilibrium phases in samples treated at oxygen partial pressure of 10 À5 Pa. Vanadium distribution between the slags and solid Pt and phase compositions were analyzed using scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and X-ray diffractomer (XRD) techniques. The effects of temperature, oxygen partial pressure, and slag basicity on the phase compositions in the slags are presented. Activities of VO 1.5 were also calculated using the value of vanadium activity in the Pt-V alloy.

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Section: Discussionmentioning

confidence: 99%

Experimental Study of Phase Equilibria in CaO–SiO₂–MgO–Al₂O₃–V₂O₃ Slags

Yang

Teng

Seetharaman

2014

steel research int.

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“…The dissolved vanadium oxide content of slags has been reported by Vermaak and Pistorius (2000). Their 4 Iron-vanadium phase diagram (Massalski, 1986) Vermaak (2000) also examined the metallic droplet content of industrial ferrovanadium slags.…”

Section: Aluminothermic Smelting Of Vanadium Oxidesmentioning

confidence: 99%

“…Windimurra operators do not measure the temperature during smelting but believe that it mostly lies between 1850uC and 1900uC. Vermaak and Pistorius (2000) give a tapping temperature for the unnamed South African smelter of 1840uC. A temperature of 1850uC will be assumed for the modelling.…”

Section: Temperaturementioning

confidence: 99%

Understanding ferrovanadium smelting through computational thermodynamics modelling

Swinbourne

Richardson²,

Cabalteja³

2016

Mineral Processing and Extractive Metallurgy

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Ferrovanadium is essential for the production of many alloy steels. It is made by the aluminothermic reduction of vanadium oxides, together with scrap steel and burnt lime as a flux at very high temperatures. In this work, the theory of aluminothermic reduction is discussed, and then a computational thermodynamics model is described and its input parameters are discussed and justified. The model predicted very satisfactorily the composition of both the ferrovanadium and waste slag from a heat at the Windimurra smelter in Western Australia. Moreover, the modelling revealed that published data on the activity coefficient of VO 1.5 in slag were likely to be seriously in error. It was shown that increasing the recovery of vanadium to the ferroalloy was accompanied by a rapid increase in its aluminium content, which is limited by commercial specifications. The limit on the silicon content of ferrovanadium can only be met by limiting the input of SiO 2 to the furnace. The model provides a useful basis for assessing process improvements.

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“…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. Vermaak et al measured the activity of V 2 O 3 in the CaO–Al 2 O 3 –V 2 O 3 system at 1973 K under the oxygen partial pressure of approximately 10 −13 atm. In these studies, only the effect of the composition on the activity of vanadium oxide was considered.…”

Section: Introductionmentioning

confidence: 99%

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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Equilibrium slag losses in ferrovanadium production

Cited by 12 publications

References 2 publications

Experimental Study of Phase Equilibria in CaO–SiO₂–MgO–Al₂O₃–V₂O₃ Slags

Experimental Study of Phase Equilibria in CaO–SiO₂–MgO–Al₂O₃–V₂O₃ Slags

Understanding ferrovanadium smelting through computational thermodynamics modelling

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

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Equilibrium slag losses in ferrovanadium production

Cited by 12 publications

References 2 publications

Experimental Study of Phase Equilibria in CaO–SiO2–MgO–Al2O3–V2O3 Slags

Experimental Study of Phase Equilibria in CaO–SiO2–MgO–Al2O3–V2O3 Slags

Understanding ferrovanadium smelting through computational thermodynamics modelling

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

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Experimental Study of Phase Equilibria in CaO–SiO₂–MgO–Al₂O₃–V₂O₃ Slags

Experimental Study of Phase Equilibria in CaO–SiO₂–MgO–Al₂O₃–V₂O₃ Slags

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