AlF<sub>3</sub>-Modified Carbon Anodes for Aluminum Electrolysis: Oxidation Resistance and Microstructural Evolution

The aluminum electrolysis industry faces significant challenges due to the high consumption and environmental impact of carbon anodes, which are prone to oxidation in high-temperature and strongly oxidizing environments. This study innovatively introduces aluminum fluoride (AlF<sub>3</sub&g...

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Bibliographic Details
Main Authors: Guifang Xu, Yonggang Ding, Fan Bai, Youming Zhang, Jianhua Yin, Caifeng Chen
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Inorganics
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Online Access:https://www.mdpi.com/2304-6740/13/5/165
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Summary:The aluminum electrolysis industry faces significant challenges due to the high consumption and environmental impact of carbon anodes, which are prone to oxidation in high-temperature and strongly oxidizing environments. This study innovatively introduces aluminum fluoride (AlF<sub>3</sub>) as an additive to enhance the oxidation resistance of carbon anodes for aluminum electrolysis. By systematically exploring microstructural evolution through SEM, XRD, Raman spectroscopy, and permeability analyses, it reveals that AlF<sub>3</sub> inserts fluorine atoms into carbon interlayers, forming F-C bonds that reduce interlayer spacing while promoting graphitization. Simultaneously, AlF<sub>3</sub>-derived α-Al<sub>2</sub>O<sub>3</sub> particles densify the anode and make it more compact, reaching the optimum when 7 wt.% AlF<sub>3</sub> is doped. The bulk density of the carbon anode increased to 2.08 g/cm<sup>3</sup>, porosity decreased to 0.315, and air permeability reached a minimum of 2.3 nPm. In addition, the fluorine intercalation reduces the electrical resistance to 2.12 Ω via conductive F-C clusters. The demonstrated efficacy of AlF<sub>3</sub> additives in enhancing the oxidation resistance and conductivity of carbon anodes suggests strong potential for industrial adoption, particularly in optimizing anode composition to reduce energy consumption.
ISSN:2304-6740