The influence of the initial shape and position of an anode and the curvature of the aluminum on the current distribution in prebaked aluminum cells

Mathematical modeling of the secondary current distribution in prebaked alu minum cells was used to study the influence of (1) a modified anode shape, (2) the curvature of the metal, and (3) an anode being set too high or too low. The calculations show that, if the lower corners of a new anode are cu t off by 5 cm (diagonally), the steady-state shape of the anode is reached after 3 days, as compared to 6 to 8 days for rectangular corners. If the me tal curvature corresponds to a 3 cm difference in height per 100 cm of leng th, and the sloping metal is facing a newly set horizontal anode, the curre nt density varies across the anode with a maximum of 125 pct of the normal value (0.75 A cm(-2)), and it takes 4 days until the anode is aligned with the metal. If a new anode is set 1 cm too low or too high, the initial curr ent through that anode after heatup is 123 and 84 pct, respectively, of the normal value, and it takes 4.2 and 7.7 days, respectively, until the inter polar distance is correct (45 +/- 1 mm).