A Design Principle of Bipolar Electrodes for
                                                Electrowinning Cell from Chloride Melts

Ishikawa, Tatsuo; Konda, Shoichi; Narita, Toshio

doi:10.1149/198707.0734pv

Cited by 3 publications

(2 citation statements)

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“…This means that the polarisation curve corresponding to the Alcoa process was partially simplified, enabling the convergence problems of the mathematical method to be solved. The results of their theoretical calculations were not proven experimentally, but were compared with the simplified bypass current calculations, presented by Ishikawa and Konda [20] and by Rousar [21]; reasonable agreement was obtained.…”

Section: Introductionmentioning

confidence: 93%

“…Therefore, originally an empirical approach was used to predict current efficiencies. A first attempt in this direction was undertaken by Ishikava and Konda [20]. They assumed that the electric current in a bipolar electrolyser can be divided into two parts: the first flows through all bipolar electrodes; the second flows directly from the terminal anode to the terminal cathode.…”

Section: Introductionmentioning

confidence: 99%

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Potential and current density distributions along a bipolar electrode

et al. 2007

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Potential and current density distributions were modelled and measured for an electrochemical cell with a bipolar electrode. The dimension of the bipolar electrode in the direction of current flow was extended, to enable experimental determination of the electrode potential and the local current densities at various positions inside the electrolyte and in the electrode body. The experimental results showed that the most active regions of the bipolar electrode are located at the ends of the bipolar electrode facing the terminal electrodes. The equations corresponding to the mathematical model of the experimental cell were solved using the finite volume method and gave very good qualitative agreement with the experimental data. However, some discrepancies between model predictions and experimental data were evident in the active parts of the bipolar electrode and in the variation of the terminal voltage with the total current. This was explained in terms of the active electrolyte cross-section and the electrode surface area being diminished due to the presence of gas bubbles in the system.Keywords Bipolar electrode Á Mathematical modelling Á Parasitic current Á Local potential and current density distribution Nomenclature A F Cross-sectional area of the free electrolyte space beside the bipolar electrode (m 2 ) d G Inter-electrode distance (m) d E Bipolar electrode thickness (m) E Electrode potential (V) f E Current utilisation in a bipolar cell (-) I Current (A) I E Current flowing through bipolar electrode (A) I P Parasitic current (A) I T Total current (A) j Current density (A m -2 ) n Vector normal to the boundary (m) N Number of electrolytic cells (-) r Radius (m) RResistivity (X) R F Electrolyte resistivity in the fictitious electrolyser (X) R G Average resistivity of the inter-electrode gap (X) R S Short-circuit resistivity (X) S Electrode surface (m 2 ) U Voltage (V) U r Open-circuit cell voltage (V)xPosition along the cell (m)Greek letters u Galvani potential (V) r Conductivity (S m -1 ) j F Electrolyte conductivity (S m -1 ) g Overpotential (V)

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Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Potential and current density distributions along a bipolar electrode

et al. 2007

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Anodic Dissolution Behavior of Al Alloys Containing Al₆Fe or β-AlFeSi in EmImCl–AlCl₃ Electrolyte During Electrorefining

Nunomura,

Matsushima,

Kyo

et al. 2023

J. Electrochem. Soc.

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To produce over 99.9% of high-purity Al from Al alloys containing Al6Fe or β-AlFeSi through electrorefining, their anodic dissolution and cathodic electrodeposition characteristics should be clarified. In this study, the anodic dissolution and cathodic electrodeposition behavior of Al–Fe binary and Al–Fe–Si ternary alloys were investigated in an EmImCl–AlCl3 ionic liquid electrolyte at 323 K. Anodic polarization measurements, constant potential electrolysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), field-emission SEM (FE-SEM), and energy dispersive spectroscopy (EDS) were used to study the anode and electrodeposits on the cathode. Constant potential electrolysis showed that Fe dissolved from Al6Fe in the Al–Fe anode at 0.7 V vs Al/Al(III) and from β-AlFeSi in the Al–Fe–Si anode at 1.4 V and was co-deposited with Al on the cathode. Notably, Si did not dissolve from β-AlFeSi at either potential. A combination of controlled anodic dissolution potential and the use of the Al alloy containing β-AlFeSi further suppressed the dissolution and cathodic co-deposition of Fe, affording high-purity Al on the cathode. This suggests that Al alloys with intermetallic compounds that are less likely to dissolve Fe at the anode are optimal for obtaining over 99.9% of high-purity Al from Al alloys containing Fe in the electrorefining method.

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Anodic Dissolution during Electrorefining of Al–Zn Alloys in Lewis Acidic AlCl<sub>3</sub>–EmImCl Ionic Liquid

NUNOMURA,

MATSUSHIMA,

KYO

et al. 2024

Electrochemistry

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The anodic dissolution reaction of Al-Zn alloys containing a Zn solid solution in Lewis acidic AlCl 3 -1-ethyl-3-methyl-imidazolium chloride (EmImCl) ionic liquids at various potentials is investigated herein. An enrichment layer was formed on the anode surface after applying constant potentials of 0.3 and 0.7 V in the 60 mol%AlCl 3 -40 %EmImCl (60 % AlCl 3 ) electrolyte and 0.2 V in the 67 mol%AlCl 3 -33 %EmImCl (67 %AlCl 3 ) electrolyte. Consequently, metallic Zn was detected in the enriched layer using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Notably, in the 60 %AlCl 3 electrolyte, high-purity Al was obtained at a much nobler potential than the dissolution potential of pure Zn, suggesting that the anodic dissolution of Zn from the Al-Zn alloy into the electrolyte was difficult. When electrorefining Al-Zn alloy anodes containing a Zn solid solution using 60 %AlCl 3 , which has lower acidity than the 67 %AlCl 3 electrolyte, it is possible to increase the anodic potential from 0.2 to 0.7 V. At this higher potential, high-purity Al is obtained at the cathode.

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A Design Principle of Bipolar Electrodes for Electrowinning Cell from Chloride Melts

Cited by 3 publications

References 0 publications

Potential and current density distributions along a bipolar electrode

Potential and current density distributions along a bipolar electrode

Anodic Dissolution Behavior of Al Alloys Containing Al₆Fe or β-AlFeSi in EmImCl–AlCl₃ Electrolyte During Electrorefining

Anodic Dissolution during Electrorefining of Al–Zn Alloys in Lewis Acidic AlCl<sub>3</sub>–EmImCl Ionic Liquid

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A Design Principle of Bipolar Electrodes for Electrowinning Cell from Chloride Melts

Cited by 3 publications

References 0 publications

Potential and current density distributions along a bipolar electrode

Potential and current density distributions along a bipolar electrode

Anodic Dissolution Behavior of Al Alloys Containing Al6Fe or β-AlFeSi in EmImCl–AlCl3 Electrolyte During Electrorefining

Anodic Dissolution during Electrorefining of Al–Zn Alloys in Lewis Acidic AlCl<sub>3</sub>–EmImCl Ionic Liquid

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Product

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Anodic Dissolution Behavior of Al Alloys Containing Al₆Fe or β-AlFeSi in EmImCl–AlCl₃ Electrolyte During Electrorefining