阳极电流密度对预焙阳极孔隙结构及电解消耗的影响

Influence of anodic current density on porous structures and consumption of prebaked anodes in aluminum electrolysis

采用图像分析方法对铝用预焙阳极在不同阳极电流密度下孔隙结构结构及其演变过程进行分析表征,考察孔隙率、孔径分布、形状因子、连通性等孔隙结构参数的变化规律和阳极消耗之间的关系。结果表明,随阳极电流密度升高,反应表面孔隙形状因子减小,而孔隙率、平均孔径、连通性均先减小后增大。阳极消耗和碳渣量随反应表面孔隙的形状因子、孔隙率、平均孔径、连通性的减小而降低,局部大孔孔隙率增大到某一临界值时骨料从阳极表面脱落进入电解质形成碳渣,造成阳极过量消耗。

Porous structures of prebaked anode materials at various anodic current densities were characterized by image analysis method. The relationships between anode consumption and the porous structure parameters such as porosity, pore diameter, aspect ratio and connectivity, were investigated. The results demonstrate that the aspect ratio of reaction surface decreases with increased anodie current density, while the porosity, pore diameter and connectivity first decrease and then increase. Anode consumption and the amount of carbon slag decrease as the aspect ratio, porosity, pore diameter and connectivity decrease. When local macro porous porosity increases to a critical value, the aggregates fall into the electrolyte from the anode surface to form carbon slag, which results in excessive consumption.