铝用石墨质阴极不同焙烧温度下孔隙结构演化

Porous structure evolution of graphitic cathode materials for aluminum electrolysis at various baking temperatures

采用图像分析方法研究铝用石墨质阴极在不同焙烧温度下孔隙结构特征及其演变,考察孔隙率、孔径分布、形状因子、视孔隙比表面积、连通性等参数的变化规律和孔隙复杂度的分形特征.结果表明:随着焙烧温度增加,孔隙率逐渐增大,而视孔隙比表面积、形状因子和连通性呈先减小后增大趋势;石墨质阴极试样不同温度下焙烧生成孔隙均符合分形规律,借助图像分析孔隙结构参数和分形维数可界定不同典型焙烧温度下阴极孔隙结构的演变特征,并据此提出相应的孔隙特征演化模式.

The porous structures and their evolution of graphitic cathode materials at various baking temperatures were investigated using the image analysis method. The porous structure parameters, such as porosity, pore size distribution, aspect ratio, specific sur-face area, and pore connectivity, were statistically calculated and the fractal features showing the degree of porous complexity were also analyzed. It is found that the porosity increases with increasing baking temperature, while the specific surface area, aspect ratio, and connectivity first decrease and then increase. The porous structure evolution of graphitic cathodes abides by the law of fractal behaviors and hence an evolution model has been proposed. This result indicates that the image analysis parameters and the fractal dimension can apply for characterizing the degree of porous structure evolution when subjected to a given baking temperature.