Electrocatalysis of carbon anode in aluminium electrolysis

摘要

The anodic over voltage of the carbon anode in aluminum electrolysis is of the order of 0.6 V at normal current densities. However, it can be reduced somewhat by doping the anode carbon with various inorganic compounds. A new apparatus was designed to improve the precision of over voltage measurements. Anodes were doped with MgAl_2O_4 and AlF_3 both by impregnation of the coke and by adding powder, and the measured over voltage was compared with that of Undoped samples. For prebake type anodes baked at around 1150 deg. C, the anodic overvoltage was reduced by 40-60 mV, And for Soderberg type anodes, baked at 950 deg. C, by 60-80 mV.