Cathode Process at the Electrolysis of KF-AlF3-Al2O3Melts and Suspensions

Nikolaev, A. Yu.; Suzdaltsev, Andrey; Polyakov, P. V.; Zaikov, Yu. P.

doi:10.1149/2.0491708jes

Cited by 19 publications

(9 citation statements)

References 25 publications

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“…The results obtained up to date [45] support the idea of aluminium production in alumina suspension at 750-800 °C at low current densities of 0.1-0.3 A cm -2 . Higher values often lead to the anode or cathode passivation, uncontrollable change in cell voltage and temperature.…”

Section: Electrolysis Testssupporting

confidence: 79%

“…Much attention was paid to the study of cathode polarization in melts and suspensions [44,45]. The effect of the temperature (670-800 °С), cathode material (tungsten, glassy carbon), ratio [KF]/[AlF3] (1.3 and 1.5 mol mol -1 ), φ (0; 0.18 and 0.30) on the kinetic parameters of the aluminium reduction from the KF-AlF3-Al2O3 melts and suspensions were studied both under stationary and non-stationary conditions.…”

Section: Cathodic Processmentioning

confidence: 99%

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Electrolysis of Low-temperature Suspensions: An Update

Yasinskiy

Suzdaltsev

Padamata

et al. 2020

The Minerals, Metals &Amp; Materials Series

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Among different "novel" technologies for eco-friendly aluminium production with zero greenhouse gas emissions, the electrolysis of alumina suspension (or slurry) based on halide melts deserves more attention than it got recently. The original idea of the slurry was first proposed by Theodor R. Beck and has been modified and developed basically by Petr V. Polyakov. This paper presents a comprehensive analysis of the current status of this technology, future opportunities, and the new experimental results, which have not been published yet. This overview covers the properties of high-temperature suspensions, including sedimentation behaviour and apparent electrical conductivity; anodic process on oxygen-evolving electrodes, including the polarization characteristics and the bubble behaviour at vertical anodes; cathodic process on wettable substrates; primary electrolysis results; and the general considerations touching upon the possible cell designs and the thermal balance. The future scope of the technology and possible applications are discussed.

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Section: Electrolysis Testssupporting

confidence: 79%

Section: Cathodic Processmentioning

confidence: 99%

Electrolysis of Low-temperature Suspensions: An Update

Yasinskiy

Suzdaltsev

Padamata

et al. 2020

The Minerals, Metals &Amp; Materials Series

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“…□ in terms of the cathodic process the lower CR is preferable due to higher limiting currents of aluminium reduction [31], so the optimal CR value can be between 1.3 and 1.4.…”

Section: Fig 5 Cyclic Voltammograms For the Anode In Melts With Different Cr (12-15) At 700 And 800 °Cmentioning

confidence: 99%

Anodic process on Cu−Al alloy in KF−AlF3−Al2O3 melts and suspensions

Padamata

Yasinskiy

Polyakov

2020

Transactions of Nonferrous Metals Society of China

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Inert anode development has been a topic of interest for decades. Cu-Al, Fe-Ni based alloys have shown promising results in low-temperature melts. Metallic anodes tend to contaminate the produced aluminium with their corrosion products and introducing alumina suspension particles in the electrolyte could resolve this problem by suppressing the convective transfer of corrosion products toward aluminium produced. In this paper, anodic processes on Cu-10Al electrode in molten KF-AlF3-Al2O3 (5 wt. %) and suspensions were characterized. Effects of cryolite ratio CR ( % % 3 ), temperature and particle volume fraction (φ= 0 -0.15) on the electrochemical behaviour of the anode were demonstrated. The results suggest that CR = 1.4 at 800 °C with the particle volume fraction of not more than 0.09 are better parameters for the usage of Cu-10Al anode. At melts with φ= 0.15 at all temperatures and CR values, a low current density was observed.

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“…The temperature of 800 °C has been chosen as an optimal value for further study in the 1.3KF-AlF 3 melt. Cryolite ratio (CR=[KF]/[AlF 3 ]=1.3) has been chosen according to the results of previous work [26].…”

Section: Methodsmentioning

confidence: 99%

“…Other researchers [16,25] . The diffusion coefficients of these electroactive particles in studied fluoride melt were reported to be in the wide range of 10 -7 [24] -10 -4 cm 2 •s -1 [26]. There is also a disagreement of different points of view on the ionic structure of both molten fluoride and chloride melts and electrode processes as well.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical characterization of the liquid aluminium bipolar electrode for extraction of noble metals from spent catalysts

Yasinskiy¹,

Padamata²,

Polyakov³

et al. 2019

nfm

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Regularities of the cathodic and the anodic behaviour of aluminium on tungsten in halide melts are investigated. The study of such systems is relevant in connection with the prospects for their use as bipolar electrodes for efficient extraction of noble metals from spent petrochemical Al 2 O 3 -based catalysts by the electrometallurgical method with associated production of highpurity aluminium and oxygen. Stationary and non-stationary polarization curves were obtained for the reduction and the oxidation of aluminium in molten NaCl-KCl+5wt.%AlF 3 and 1.3KF-AlF 3 systems at 700 -850 °C (973 -1123 K) in the range of current densities from 0.01 to 1.5 A•cm -2 and in the range of potential sweep rates from 0.01 to 5 V•s -1 . Electrochemical characterization of the electrode showed that electroactive particles in chloride-based melts have higher diffusion coefficients (in comparison with fluoride melt) due to the high concentration of Na(I) and K(I) cations, low density and viscosity of the melt. Electrochemical dissolution and reduction of aluminium in both chloride-based and fluoride melts are quasi-reversible diffusioncontrolled processes complicated by several parallel phenomena. Cathodic reduction of Al(III) in both studied melts occurs at high overvoltages (more than 200 mV at 0.1 A•cm -2 ) with the limiting current densities of 0.3-0.4 A•cm -2 at 800 °C. The cathodic reduction of Na(I) starts in chloride-based melts at the potential of -0.5 -(-0.7) V relative to Al reference electrode; the reduction of K(I) in both studied melts starts at -1.0 -(-1.2) V. In general, the kinetic parameters of the processes show that the extraction in two-sectioned cell can be beneficially performed at 800 °C with high current densities, and the liquid aluminium bipolar electrode seems to be the promising solution.

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Cathode Process at the Electrolysis of KF-AlF₃-Al₂O₃Melts and Suspensions

Cited by 19 publications

References 25 publications

Electrolysis of Low-temperature Suspensions: An Update

Electrolysis of Low-temperature Suspensions: An Update

Anodic process on Cu−Al alloy in KF−AlF3−Al2O3 melts and suspensions

Electrochemical characterization of the liquid aluminium bipolar electrode for extraction of noble metals from spent catalysts

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