Study on the Electrolysis Expansion of Carbon Cathode in [K₃AlF₆/Na₃AlF₆]-AlF₃-Al₂O₃ Low Temperature Melts

Abstract:

Electrolysis expansion of carbon cathodes due to alkali metal penetration in [K₃AlF₆/Na₃AlF₆]-AlF₃-Al₂O₃ melts was tested. Effect of ampere density and superheating temperature on the electrolysis expansion was studied. A mathematical model was got to numerically describe electrolysis expansion performance of carbon cathode. The results indicated that K and Na penetrate into carbon cathode from outside to inside. Ampere density and superheating temperature had a great effect on the electrolysis expansion of carbon cathode. With the superheating temperature increasing from 10 to 50, electrolysis expansion increased from 1.41% to 2.10% gradually. With the ampere density increasing, the increase trend of electrolysis expansion was not linear. When ampere density was lower than 0.4A / cm² and greater than 0.7A / cm², cathode electrolysis expansion obviously increased with the increase of ampere density. Meanwhile, cathode electrolysis expansion tended to be constant as the ampere density changed at the range of 0.4A / cm² to 0.7A / cm².The results of the mathematical model in this study had a good agreement with the test results. This model would be helpful to accurately describe the anti-penetration performance of K and Na on the carbon cathode.

• Periodical: Materials Science Forum (Volume 749)
• Pages: 633-642
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.749.633
• Online since: March 2013
• Authors: Zhao Fang, Peng Fei Xu, Jian Xu, Lin Bo Li, Jun Zhu
• Keywords: Aluminium Electrolysis, Ampere Density, Cathode Material, Electrolysis Expansion, Superheating Temperature

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