Theoretical and experimental study of anode process at the carbon in KF-AlF3-Al2O3 melts / Nekrasov V. N.,Suzdaltsev A. V.,Limanovskaya O. V.,Khramov A. P.,Zaikov Yu. P. // ELECTROCHIMICA ACTA. - 2012. - V. 75, l. . - P. 296-304.

ISSN/EISSN:

0013-4686 / нет данных

Type:

Article

Abstract:

The influence of the {[}KF]/{[}AlF3] ratio (1.1-1.5 mol mol(-1)), the Al2O3 concentration (1-5 wt.\%) and the temperature (973-1073 K) on the overpotential of the anode process for a glassy carbon electrode in a KF-AlF3-Al2O3 melt under stationary and non-stationary conditions was studied by galvanostatic polarisation and chronopotentiometry. A theoretical (mathematical) description of the two-step electrode process at the carbon anode in KF-AlF3-Al2O3 melts under stationary and non-stationary conditions is suggested. The charge of the electric double-layer, the formation of an intermediate COads, adsorption product at the anode surface, the limitations of the current transfer, which include the charge transfer through the electrode/electrolyte interface, and the diffusion and chemical interaction of the electroactive ions in the melt near the anode surface were taken onto account. Alterations of the basic parameters of the process were monitored and analysed. Estimates of anode process kinetics parameters (e.g., exchange current densities and the degree of the anode surface coverage by the intermediate product COads) for different experimental conditions were made by a comparison of the modelled and experimental polarisation curves. The electrochemical desorption of the intermediate product COads from the anode surface (the second step) was shown to be relatively slower than the charge transfer process (the first step). In addition, slow chemical reactions at current densities of 0.1-1 A cm(-2) can occur prior to the electrode process. (C) 2012 Elsevier Ltd. All rights reserved.

Author keywords:

Aluminium electrolysis; Low temperature electrolyte; Anode process; Galvanostatic polarisation; Mathematical description CRYOLITE-ALUMINA MELTS; ELECTROCHEMICAL-BEHAVIOR; VAPOR-PRESSURE; GRAPHITE; SOLUBILITY; THERMODYNAMICS; ELECTROLYTES; EQUILIBRIA; SYSTEM; LI

DOI:

10.1016/j.electacta.2012.05.00

Web of Science ID:

ISI:000306884100039

Соавторы в МНС:

Другие поля

Поле	Значение
Month	JUL 30
Publisher	PERGAMON-ELSEVIER SCIENCE LTD
Address	THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND
Language	English
Keywords-Plus	CRYOLITE-ALUMINA MELTS; ELECTROCHEMICAL-BEHAVIOR; VAPOR-PRESSURE; GRAPHITE; SOLUBILITY; THERMODYNAMICS; ELECTROLYTES; EQUILIBRIA; SYSTEM; LI
Research-Areas	Electrochemistry
Web-of-Science-Categories	Electrochemistry
Author-Email	suzdaltsev\_av@mail.ru
ResearcherID-Numbers	Suzdaltsev, Andrey/G-8015-2012
ORCID-Numbers	Suzdaltsev, Andrey/0000-0003-3004-7611
Funding-Acknowledgement	Ural Branch of the Russian Academy of Sciences
Funding-Text	The work was financially supported by the program of the Ural Branch of the Russian Academy of Sciences.
Number-of-Cited-References	31
Usage-Count-Last-180-days	3
Usage-Count-Since-2013	27
Journal-ISO	Electrochim. Acta
Doc-Delivery-Number	980HL