Analysis of prebake anode assembly of hall-heroult cells to enhance life of conductor bar

Significant efforts have been made over the years at Hindalco Smelter Renukoot to improve the efficiency of smelter operation by pushing the design limit of various components. Enhancing the life of copper bar conductor, which holds the anode assembly, is one such example. These bars are exposed to static load of the anode assembly and severe thermal conditions and due to bath proximity. Failure of these bars was seen due to cracks after few cycles, thus preventing repeated use of these bars. The causes of failure have been analyzed by conducting a combination of thermo-mechanical modeling and micro-structural analysis. A simple finite element model with experimentally measured temperatures as boundary conditions has been used for thermal stress analysis. The creep deformation has been identified as the primary mechanism. The point of onset of creep can be attributed to micro-structural deficiencies and high temperature exposure of the bar.