Open AccessVisualization of Anode Effect in Aluminum Electrolysis
Author(s) -
Bingliang Gao,
Hongkun Niu,
Yuechao Guan,
Zhaowen Wang,
Jingjing Liu,
Marilyn Taylor,
John Chen
Publication year - 2022
Publication title -
journal of the electrochemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.258
H-Index - 271
eISSN - 1945-7111
pISSN - 0013-4651
DOI - 10.1149/1945-7111/ac4bf5
Subject(s) - anode , electrolyte , electrolysis , materials science , carbon fibers , aluminium , metallurgy , chemical engineering , composite material , chemistry , electrode , composite number , engineering
The aluminum smelting industry is a significant emitter of greenhouse gases. In addition to the emission of CO 2 during normal operation, perfluorocarbons (PFCs) are generated when the Al 2 O 3 concentration in the electrolyte falls below a certain critical level, a phenomenon referred to as anode effect . Understanding the mechanism of anode effect formation has become essential to mitigating or preventing its occurrence. Here, the anode effect occurring at an industrial carbon anode with an underside surface area of 50 cm 2 (10 × 5 cm) was observed in a high-temperature see-through Hall-Héroult electrolytic cell operating at 940 °C. The visual observation of the phenomenon confirmed that the anode effect is caused by the formation of an intermediate, insulating CF x film. No gas layer or large bubbles were observed during the anode effect. The sharp increase of the cell voltage is due to the insulation of the continuous intermediate unbroken film, which has relatively much higher electrical resistance than the carbon anode and electrolyte.