Theoretical and experimental study of anode process at the carbon in KF–AlF3–Al2O3 melts

Nekrasov, V. N.; Suzdaltsev, Andrey; Limanovskaya, O. V.; Khramov, A. P.; Zaikov, Yu. P.

doi:10.1016/j.electacta.2012.05.007

Cited by 24 publications

(37 citation statements)

References 20 publications

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“…In the scientific, technical, and educational litera ture on the electrometallurgy of primary aluminium, some hypotheses concerning the mechanisms of cathodic and anodic processes during the electrolysis of cryolite alumina melts are presented [1][2][3][4][5][6][7][8]. In some cases, these are presented as detailed schemes [9].…”

Section: Introductionmentioning

confidence: 99%

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Modern views on the composition of anionic oxy-fluoride complexes of aluminium and their rearrangement during the electrolysis of cryolite-alumina melts

Khramov

Шуров

2014

Russ. Metall.

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Some consequences of the hypothesis of the absence of free Fions in cryolite alumina melts are observed. The melt at 1 < CR < 3 is assumed to consist of the complexes and and alkali metal cations. A formal stoichiometric study of the processes occurring during electrolysis is performed on the basis of the accepted hypothesis. Judgments about some of the features of the electrode reactions and chemical reactions in the electrolyte volume are presented. The reaction schemes for the instances with and without the subsequent/preceding chemical reaction near the electrode or in the mol ten salt volume are given. The mass flows of various forms of ionic complexes through the electrolyte volume are given for these schemes. Definitive conclusions are not made in the study, but the range of possible variants for the electrochemical routes of the overall chemical reaction in the cell is limited.

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Section: Introductionmentioning

confidence: 99%

“…We have tried to consistently adhere to this view and on base of this hypothesis to present schemes of the over all reactions. In [7], some reactions on the basis of this hypothesis are recorded for the K containing melt. The electrolyte layer near the cathode (catholyte) can be considered an exception.…”

Section: Introductionmentioning

confidence: 99%

Modern views on the composition of anionic oxy-fluoride complexes of aluminium and their rearrangement during the electrolysis of cryolite-alumina melts

Khramov

Шуров

2014

Russ. Metall.

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“…Besides CaF 2 , MgF 2 and LiF can also be used. The normal cell temperature is between 1,213 and 1,253 K [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

Cathodic electrochemical behavior in Na3AlF6-Al2O3-LiF-based melts at tungsten electrode with various cryolite ratios

Tao

Peng

et al. 2014

Rare Met.

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The cathodic behavior at tungsten electrode in Na 3 AlF 6 -Al 2 O 3 -LiF-based melt with various cryolite ratios was investigated by means of potentiodynamic cathodic polarization, potentiostatic electrolysis, chronopotentiometry, and open-circuit chronopotentiometry. The results show that the formation process of Al-W intermetallic compound is controlled by both diffusion and charge transfer when the cryolite ratio is below 2.5, and is completely controlled by diffusion when cryolite ratio is above 2.5. The deposition process of metal aluminum is completely charge-transfer controlled. Sodium vapor releases along with the deposition of metal aluminum as crylite ratio increases, which leads to a great influence on current efficiency. When the cryolite ratio is lower than 2.0, the critical cathodic current density of deposited aluminum at tungsten electrode is about 150 mAÁcm -2 , but the current density is above 200 mAÁcm -2 under other experimental conditions. A higher cryolite ratio can cause a higher cathodic overvoltage. The relative content of Al layer is higher with the decrease of cryolite ratio, and Al layer easily strips into the molten salt when the cryolite ratio is higher than 2.5.

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“…At present extensive investigations are performed to develop the physicochemical fundamentals of pro ducing aluminum by the electrolysis of the KF-NaF-AlF 3 -Al 2 O 3 melt at 750-850°C [1][2][3][4][5]. Owing to this low temperature, one of the advantages of the devel oped technology is the possibility of using noncon sumable oxide and oxide-metal anodes on which oxy gen forms during electrolysis [5].…”

Section: Introductionmentioning

confidence: 99%

Stationary anodic process at platinum in KF-NaF-AlF3-Al2O3 melts

et al. 2014

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The kinetics of the anodic process at platinum in KF-NaF-AlF 3 -Al 2 O 3 melts in the temperature range 725-800°C is studied using potentiostatic polarization. Platinum is considered as an indifferent oxy gen evolving electrode, and a two stage scheme is proposed for the anodic process on it. According to this scheme, primary charge transfer with the formation of adsorbed O ads particles is accompanied by their des orption according to a physical or an electrochemical mechanism. The polarization dependences of the anodic process on platinum are calculated under stationary conditions with allowance for the predominance of different stages of the process and a desorption mechanism. The calculated and experimental stationary anodic polarization dependences are compared.

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Theoretical and experimental study of anode process at the carbon in KF–AlF3–Al2O3 melts

Cited by 24 publications

References 20 publications

Modern views on the composition of anionic oxy-fluoride complexes of aluminium and their rearrangement during the electrolysis of cryolite-alumina melts

Modern views on the composition of anionic oxy-fluoride complexes of aluminium and their rearrangement during the electrolysis of cryolite-alumina melts

Cathodic electrochemical behavior in Na3AlF6-Al2O3-LiF-based melts at tungsten electrode with various cryolite ratios

Stationary anodic process at platinum in KF-NaF-AlF3-Al2O3 melts

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