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过程工程学报 ›› 2022, Vol. 22 ›› Issue (12): 1739-1746.DOI: 10.12034/j.issn.1009-606X.221404

• 研究论文 • 上一篇    下一篇

TiB2的分散行为对铝电解惰性阴极材料性能的影响

张子阳1,2， 王维1,2*， 王伟彬1,2
  

  1. 1. 河南科技大学材料科学与工程学院，河南 洛阳 471023 2. 有色金属共性技术河南省协同创新中心，河南 洛阳 471023
  • 收稿日期:2021-12-06 修回日期:2022-03-03 出版日期:2022-12-28 发布日期:2022-12-30
  • 通讯作者: 王维 wwlyzwkj_003@163.com
  • 基金资助:
    从原子角度研究铝电解碳素阴极失效的机理

Influence of TiB2 dispersion behavior on the performance of inert cathode materials for aluminum electrolysis

Ziyang ZHANG1,2,  Wei WANG1,2*,  Weibin WANG1,2   

  1. 1. College of Materials Science and Engineering, Henan University of Science and Technology, Luoyang, Henan 471023, China 2. Collaborative Innovation Center of Nonferrous Metals Henan Province, Luoyang, Henan 471023, China
  • Received:2021-12-06 Revised:2022-03-03 Online:2022-12-28 Published:2022-12-30
  • Contact: Wei WeiWANG wwlyzwkj_003@163.com

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摘要： 为了解TiB2对铝电解阴极材料性能的影响，在实验室通过热压烧结制备TiB2-C复合阴极材料，并对制备的阴极试样进行在线钠膨胀测试。结合XRD, SEM和TEM等微观分析手段，研究钠元素对阴极的渗透、TiB2-C复合阴极材料与基体之间的界面行为和TiC对阴极材料性能的影响。结果表明，在电解过程中，TiC通过溶解-析出方式提高了阴极材料石墨化度，改善了阴极材料的性能。在相同电流密度情况下，TiB2-C复合阴极材料能够有效降低阴极压降。通过在功能层与基体之间插入一层过渡层，改善了TiB2-C复合阴极材料与基体之间的黏合，能够有效减少钠元素对阴极的侵蚀。该研究对延长电解槽阴极的使用寿命以及降低铝电解的生产能耗具有理论指导意义。

关键词: 铝电解, 惰性阴极, TiB2-C复合材料, 功能梯度材料, TiC, 催化石墨化机理

Abstract: Due to its good wettability to molten aluminum and good corrosion resistance to the molten electrolyte, TiB2 is a promising cathode material. Recently, a number of studies on TiB2-C composite cathode materials have been undertaken by researchers. Yet, the mechanism of TiB2 reducing sodium and electrolyte penetration is reported scarcely. In order to understand the effect of TiB2 on the performance of cathode materials for aluminum electrolysis, TiB2-C composite cathode materials were prepared by the hot press sintering process, and experimental investigation of sodium expansion of cathode samples was conducted in laboratory aluminum electrolysis cells. By virtue of detailed SEM, TEM, and XRD analyses, the interfacial behavior between TiB2-C composite material and the substrate, the effect of TiC on the performance of the cathode material, and sodium penetration were investigated elaborately. The results showed that TiC generated in the process of firing can increase the degree of graphitization and coherence length of La by converting the disordered carbon into graphite crystals during aluminum electrolysis. This catalysis process, which was called dissolution-precipitation mechanism, can improve the performance of cathode materials and reduce the penetration of electrolytes and sodium to the cathode. The electrical resistivity with TiB2-C composite cathode was 55.6 μΩ?m at 950℃, and that with the carbon cathode was 96.7 μΩ?m applied on the same temperature. As a result, the cathode voltage drop can be effectively reduced by using a TiB2-C composite cathode, which reduced energy consumption in production. The composition and structure of the cathode were changed in a gradient by inserting a transition layer so that the properties and functions of the cathode also were changed in a gradient along the gradient direction. Generally, cracking would initiate and propagate between the composite layer and carbon base because of a large mismatch of their thermal expansions. But the interface bonding between the TiB2-C composite and the substrate was significantly improved by inserting a transition layer, which can remarkably decrease sodium penetration. This work is useful for increasing the service life of cathodes and reducing the energy consumption of aluminum electrolysis.

Key words: aluminum electrolysis, inert cathode, TiB2-C composite material, functionally graded material, TiC, mechanism of catalytic graphitization