Gaseous corrosion of alumino-silicate refractories in anode baking furnaces used for aluminium production, part 2

In order to contribute to a better knowledge of the mechanisms of corrosion in refractory bricks used in the flue-wall of anode baking furnaces, the study of post-mortem samples and of corrosion by gaseous sodium with a carbon monoxide environment in a laboratory test were studied. Under conditions close to those in anode baking furnaces, the corrosion tests showed the formation of a rich sodium vitreous phase in the matrix of corroded samples. The use of mullitized andalusite in the matrix of refractory bricks reduced the formation of the vitreous phases during the corrosion by gaseous sodium. To increase the resistance to corrosion, it is advised: • To add fine andalusite particles and reactive alumina to the matrix to support the formation of secondary mullite • To decrease the clay content in order to reduce the quantity of vitreous phase • To optimize the firing temperature.