Current distribution in aluminium electrolysis cells with S�derberg anodes Part II: Mathematical modelling

Abstract

The current distribution in an aluminium electrolysis cell with a Soderberg anode was calculated to supplement measured data (Part I of this study). A numerical method based on the conservative scheme was used. A 2D cross section of a commercial cell was considered and the electric fields in the anode, cathode and the electrolyte were considered under steady state conditions. Four different approximations of a curvilinear boundary were proposed. The overvoltage for both electrodes was introduced. The current density decreased along the side of the anode from the nominal value 0.8 A cm−2 on the underside to 0.26 A cm−2 in the upper part near the surface of the electrolyte. The calculated current density along the side of the Soderberg anode for all the approximations was compared with the measured data, and the agreement was within 10 to 15%. In the curved part of the anode the differences between measured and calculated values were 20–28%; but in this region the accuracy of the experimental data was in the same range. Also the finite element method was used for the comparison of the calculated current density.