Airburn reaction and carboxy reaction result in the excess consumption of carbon anode in
aluminum electrolysis.
To
reduce the excess carbon consumption, carbon anode was doped with
aluminum-containing additives, such as Al, Al_4C_3,
AlF_3 and Al_2O_3. Their reactivity in air and CO_2 was determined with an isothermal-gravimetric method to study the effect of
aluminum-containing additives on the reactivity in air and CO_2 of carbon anode. Results shown that the airburn reactivity at
450℃ and carboxy reactivity at 970℃ of carbon anode both decreased with Al-containing additives adding, while shown
a minimum with the amount of Al_4C_3, AlF_3 and Al_2O_3 increasing. However,all Al-containing additives increase the airburn
reactivity at 550℃ of carbon anodes. Coke yield measurement and XRD examination with aluminum containing additives
doped pitch cokes revealed that the effect of Al-containing additives on the airburn reactivity and carboxy reactivity of car-
bon anode would result from chemical factors and structural factors.