石油焦煅烧程度对铝用炭阳极显微结构及电解消耗的影响

以不同煅烧程度石油焦为骨料，煤沥青为黏结剂制备铝用低煅焦炭阳极.通过激光共聚焦扫描显微镜和图像分析方法对炭阳极孔隙结构进行分析表征，并考察阳极反应性和电解消耗性能.在煅后焦微晶尺寸1.7~2.7 nm范围内降低石油焦煅烧程度，炭阳极小孔隙逐渐沿骨料-黏结剂界面演变为裂纹状大孔隙，炭阳极孔隙率、形状因子及连通率均先减小后增大，视孔隙比表面积呈减小趋势.煅后焦微晶尺寸降低至1.9 nm较为适宜，对应的炭阳极空气和CO2反应质量损失率最少为9.6%和3.0%，每吨铝阳极碳耗为355.4 kg.低煅焦炭阳极过量消耗机制从以黏结剂选择性消耗转变为骨料与黏结剂共同消耗，使碳渣量减少.

Impact of coke calcination levels on the microstructure and consumption of carbon anodes in aluminum electrolysis

Carbon anodes for aluminum electrolysis were made of different calcination levels of coke as an aggregate and coal pitch as a binder. The porous structure parameters of carbon anode materials were characterized by using laser confocal scanning microscopy and the image analysis method. The anodic reaction and electrolysis consumption were also investigated in a lab scale aluminum elec-trolysis cell. The results demonstrate that the micropores gradually extend to crack-like macropores along the aggregate- binder inter-face with increasing coke calcination levels. The porosity, aspect ratio and connectivity first decrease and then increase, while the spe-cific surface area decreases. It is appropriate to reduce the crystallite height of calcined cokes to 1. 9 nm, so that the corresponding an-odes can have the air reactivity of 9. 6%, the CO2 reactivity of 3. 0%, and the anode consumption of 355. 4 kg per ton aluminum. The excessive consumption mechanism for the low calcined anode cokes may change from selective consumption of the binder to co-con-sumption of both the aggregate and the binder, which can reduce the carbon dust and the total carbon consumption in aluminum elec-trolysis.