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Thermodynamic considerations of the corrosion of nickel ferrite refractory by Na3AlF6-AlF3-CaF2-Al 2O3 bath

Journal Article


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Abstract


  • Thermodynamic analysis was carried out to interpret the results of corrosion testing of nickel ferrite samples in cryolite-based baths. The equilibrium between cryolite-based baths and nickel ferrite was considered. Isopleths between cryolite-based baths and nickel ferrite confirmed that for the temperature range of interest (1223-1273 K) there was limited solubility of nickel ferrite in the bath. To better understand the formation of the metal from nickel ferrite, the effect of reducing potentials on nickel ferrite and nickel ferrite-cryolite-based bath systems were considered. The formation of a metal phase was predicted at relatively high pO2. The metal phase was nickel-rich at higher pO2, becoming enriched in iron as the pO 2 decreased. The oxide phases seen in corroded nickel ferrite samples corresponded to the spinel phase in the thermodynamic calculations. Penetration of aluminium oxides into the spinel phase seen in the experimental samples occurred only under a reducing potential.

Publication Date


  • 2014

Citation


  • Longbottom, R. J., Nightingale, S. A. & Monaghan, B. J. (2014). Thermodynamic considerations of the corrosion of nickel ferrite refractory by Na3AlF6-AlF3-CaF2-Al 2O3 bath. Transactions of the Institutions of Mining and Metallurgy, Section C: Mineral Processing and Extractive Metallurgy, 123 (2), 93-103.

Scopus Eid


  • 2-s2.0-84901725189

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=3811&context=eispapers

Ro Metadata Url


  • http://ro.uow.edu.au/eispapers/2802

Number Of Pages


  • 10

Start Page


  • 93

End Page


  • 103

Volume


  • 123

Issue


  • 2

Abstract


  • Thermodynamic analysis was carried out to interpret the results of corrosion testing of nickel ferrite samples in cryolite-based baths. The equilibrium between cryolite-based baths and nickel ferrite was considered. Isopleths between cryolite-based baths and nickel ferrite confirmed that for the temperature range of interest (1223-1273 K) there was limited solubility of nickel ferrite in the bath. To better understand the formation of the metal from nickel ferrite, the effect of reducing potentials on nickel ferrite and nickel ferrite-cryolite-based bath systems were considered. The formation of a metal phase was predicted at relatively high pO2. The metal phase was nickel-rich at higher pO2, becoming enriched in iron as the pO 2 decreased. The oxide phases seen in corroded nickel ferrite samples corresponded to the spinel phase in the thermodynamic calculations. Penetration of aluminium oxides into the spinel phase seen in the experimental samples occurred only under a reducing potential.

Publication Date


  • 2014

Citation


  • Longbottom, R. J., Nightingale, S. A. & Monaghan, B. J. (2014). Thermodynamic considerations of the corrosion of nickel ferrite refractory by Na3AlF6-AlF3-CaF2-Al 2O3 bath. Transactions of the Institutions of Mining and Metallurgy, Section C: Mineral Processing and Extractive Metallurgy, 123 (2), 93-103.

Scopus Eid


  • 2-s2.0-84901725189

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=3811&context=eispapers

Ro Metadata Url


  • http://ro.uow.edu.au/eispapers/2802

Number Of Pages


  • 10

Start Page


  • 93

End Page


  • 103

Volume


  • 123

Issue


  • 2