SCI和EI收录∣中国化工学会会刊

中国化学工程学报 ›› 2021, Vol. 39 ›› Issue (11): 314-319.DOI: 10.1016/j.cjche.2021.05.011

• Material and Product Engineering • 上一篇    

Influence of anode current density on carbon parasitic reactions during electrolysis

Tongxiang Ma, Lang Zhao, Yu Yang, Liwen Hu, Shengfu Zhang, Meilong Hu   

  1. College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China
  • 收稿日期:2021-03-12 修回日期:2021-05-18 出版日期:2021-11-28 发布日期:2021-12-27
  • 通讯作者: Meilong Hu
  • 基金资助:
    This work was supported financially by the National Natural Science Foundation of China (51674054), and supported by the Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and New Materials, Chongqing University, China.

Influence of anode current density on carbon parasitic reactions during electrolysis

Tongxiang Ma, Lang Zhao, Yu Yang, Liwen Hu, Shengfu Zhang, Meilong Hu   

  1. College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China
  • Received:2021-03-12 Revised:2021-05-18 Online:2021-11-28 Published:2021-12-27
  • Contact: Meilong Hu
  • Supported by:
    This work was supported financially by the National Natural Science Foundation of China (51674054), and supported by the Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and New Materials, Chongqing University, China.

摘要: In the electro-deoxidation process, carbon parasitic reaction (CO32- + 4e-=C + 3O2-) usually occurs when using carbon materials as the anode, which leads to increase of the carbon content in the final metal and decrease of the current efficiency of the process. The aim of this work is to reduce the negative effect of carbon parasitic reaction on the electrolysis process by adjusting anode current density. The results indicate that lower graphite anode area can achieve higher current density, which is helpful to increase the nucleation site of CO2 bubbles. Most of CO2 would be released from the anode instead of dissolution in the molten CaCl2 and reacting with O2- to form CO32-, thus decreasing the carbon parasitic reaction of the process. Furthermore, the results of the compared experiments show that when the anode area decreases from 172.78 to 4.99 cm2, CO2 concentration in the released gases increases significantly, the carbon mass content in the final metal product decreased from 1.09% to 0.13%, and the current efficiency increased from 6.65% to 36.50%. This study determined a suitable anode current density range for reducing carbon parasitic reaction and provides a valuable reference for the selection of the anode in the electrolysis process.

关键词: Anode area, Anode current density, Carbon parasitic reactions, Current efficiency

Abstract: In the electro-deoxidation process, carbon parasitic reaction (CO32- + 4e-=C + 3O2-) usually occurs when using carbon materials as the anode, which leads to increase of the carbon content in the final metal and decrease of the current efficiency of the process. The aim of this work is to reduce the negative effect of carbon parasitic reaction on the electrolysis process by adjusting anode current density. The results indicate that lower graphite anode area can achieve higher current density, which is helpful to increase the nucleation site of CO2 bubbles. Most of CO2 would be released from the anode instead of dissolution in the molten CaCl2 and reacting with O2- to form CO32-, thus decreasing the carbon parasitic reaction of the process. Furthermore, the results of the compared experiments show that when the anode area decreases from 172.78 to 4.99 cm2, CO2 concentration in the released gases increases significantly, the carbon mass content in the final metal product decreased from 1.09% to 0.13%, and the current efficiency increased from 6.65% to 36.50%. This study determined a suitable anode current density range for reducing carbon parasitic reaction and provides a valuable reference for the selection of the anode in the electrolysis process.

Key words: Anode area, Anode current density, Carbon parasitic reactions, Current efficiency