Sedimentation behavior of high-temperature concentrated colloidal suspension based on potassium cryolite

Transactions of Nonferrous Metals Society of China

Polyakov

2020

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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.

Section: Introductionmentioning

confidence: 99%

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

Transactions of Nonferrous Metals Society of China

Polyakov

2020

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“…The values at , which is probably due to experimental error. The deviation from the models be explained by the fact that the effective viscosity increases, getting closer to maximum packing fracture estimated in [58] to be ~0.32. It leads to the increase of The accuracy of experimental data has been estimated and mentioned graph in the form of error bars showing the standard deviation.…”

Section: Resultsmentioning

confidence: 49%

“…Yasinskiy et al [58], [59] investigated the sedimentation behavior of alumina suspension based on low-temperature electrolyte system KF-AlF 3 -Al 2 O 3 . The value of maximum packing fraction for smelter grade alumina was estimated to be approximately as high as 0.32 at which the particles have extremely low or zero sedimentation velocity.…”

Section: Suspension Electrolytementioning

confidence: 99%

Electrolytes and its additives used in aluminum reduction cell: a review

Polyakov

2019

Metall. Res. Technol.

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The electrolyte is considered to play the role of blood in an aluminum reduction cell and performs several vital functions as the charge transfer, the mass dissolution and transfer, the electrode products separation and the electrical work dissipation. The proper performance of listed functions is completely determined by the physical and chemical properties, which namely are the electrical conductivity, the viscosity, the vapor pressure, the liquidus and solidus temperatures, the density, the surface tension, the solubility and the dissolution rate of oxides, aluminum, carbon and the various connections and by operating conditions, which namely are the temperature, the current density, the anode-cathode distance, etc. The electrolyte affects the current efficiency and the cell voltage, which determines the specific energy consumption and the total cost of aluminum. This is the reason why different electrolytes and additives have been in the spotlight of the researchers and the enterprises for decades. This article presents the brief information about the influence of additives in the cell utilizing traditionally used sodium cryolite and different low-temperature electrolytes on physical-chemical properties and concentrates on the latest works which have not been included in widely known textbooks. The article also contains new experimental results obtained by the authors and devoted to the effective electrical conductivity of suspended unconventional electrolytes.

“…The uniformity of the average alumina particles size spatial distribution = ( ) was evaluated in [27]. Fig.…”

Section: Sedimentation Of Al2o3mentioning

confidence: 99%

Electrolysis of Low-temperature Suspensions: An Update

Suzdaltsev

The Minerals, Metals &Amp; Materials Series

et al. 2020

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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.