电解质渗透对铝电解石墨质阴极材料高温导电性的影响

Effects of Electrolyte Penetration on Pyro-conductivity of Graphitic Cathodes for Aluminum Electrolysis

测试了半石墨质(HC35)和全石墨质(HC100)两种工业阴极碳块在铝电解前后的高温电阻率。结果表明,电解前,由于热膨胀引起的有关孔隙结构参数变化影响阴极材料电阻率;电解时,钠和电解质渗透亦影响阴极电阻率。孔隙平均直径和连通率越大、曲折度越小,越有利于钠和电解质的渗透,电解前后阴极材料电阻率变化也越大。

Electrical resistivity of two industrial cathodes, 35% graphitic （HC35） and 100% graphitic （HC100）, at high temperature was tested respectively. As the results indicate, thermal expansion of cathodes results in a change of parameters of porous structure, which in turn give rise to variation of resistivity before electrolysis. After electrolysis, the change of resistivity is ascribed to penetration between sodium and electrolyte, which is strongly affected by the porous structure of cathodes. Infiltration of sodium and electrolyte into cathode is facilitated by bigger average diameter and connectivity of pores, and smaller sinuosity of connecting pores in porous structure, In turn, a better infiltration results in bigger change of resistivity after electrolysis.