Effects of Height Difference of the Recycled Stub on the Anode Performance in Hall–Héroult Cell

The deterioration of recycled stubs has significant effects on anode performance. In this study, numerical simulations are conducted to investigate the effects of the height difference on the anode performance, in which scenarios where the height of the side stubs is 5 mm to 30 mm shorter than that of the middle stubs are considered. Due to the height difference, extra cast iron goes under the shorter stubs when anode rodding, and then the cast iron-to-carbon air gap becomes large after rodding, leading to the increase in the anode voltage drop. The anode voltage drop increases with the stub height difference because of the increasing cast iron-to-carbon air gap. When the stub height difference reaches 20 mm, the anode voltage drop increment rises dramatically because the cast iron-to-carbon air gap is so large that the bottom of the stub hole wall starts to loss contact with the cast iron.