Aluminum Reduction Cell Anode - Computer Simulation And Optimization, Of The Electric Field Of The Melt And Inert Anode Heat Stress

In aluminum reduction cell, there exist complicated physical fields, and current field and temperature field are roots of other fields. Whether current field and temperature field are designed reasonably or not is critical for the design of aluminum reduction cell, therefore, the study on current field and temperature field is very important. Up to now, studies on cathode's current field and temperature field (especially freeze profile) have been well conducted. However, the current field and temperature field of anode and molten electrolyte have not been studied well due to the difficulty in ascertaining boundary conditions of electric conduct of the contact area. In order to solve the problem, a new concept was conceived in this article: By using the multiple elements and multiple properties of ANSYS software, a model of anode and molten electrolyte as a whole was built and computed, therefore, not only the ascertaining of electric conduct boundary conditions of the contact area beween anode and electrolyte was avoided, but also the current density of the contact area could be analyzed with the model's result, so the calculation precision could be enhanced.A mathematical model of thermal conduct and electric conduct of prebaked aluminum reduction cell was built based on Fourier's law and Kirchhoff's law, and finite element equations for calculating current and temperature fields of aluminum reduction cell were deduced with Galerkin method. A 3D finite element model of anode and molten electrolyte was built with ANSYS software, and with reasonable assumption of boundary conditions, the current and temperature fields of 160kA prebaked reduction cell used at a plant in our country were computed. The temperature, voltage, electric current distribution and heat balance of the cell were analyzed. As its simulation results were well coincided with the measured data, the model provided foundations for optimizing current field and temperature field of aluminum electrolysis cell. Based on the model, the structural parameters which influenced anode drop and current distribution, anode heat loss and horizontal current in aluminum were analyzed, and a scheme to improve the parameters of 160kA prebaked cell was put forward, the computed results turned out to be optimized than the original cell.In addition, in order to cooperate with the research of inert anode, the optimizing design of thermal stress of metal-ceramic gradient inert anode on the condition of electrolysis was also conducted; A 3D thermal stress model of cylindrical inert anode was built; The relationships between thermal stress distribution feature in inert anode and gradient thickness, gradient height and composition distribution of metal-ceramic was analyzed with ANSYS software; A gradient design scheme of best thermal stress distribution was put forward according to the relationships.