Aluminerie Alouette of Sept-Iles utilizes air chutes at the coke silo discharge. These air chutes are similar to a pneumatic conveyor. A large quantity of air is induced in the lower areas utilizing a series of deflectors to fluidize and assist in the material flow. The injected air angle assures the proper flow of the coke material.

The bottom of the air chutes and deflectors are subjected to abrasion. Therefore, the deflectors are protected with ceramic tiles to extend their life. Maintenance is very costly as the tiles are fragile and increase significantly the weight of the air chutes. Also, the tiles at times, are removed by deteriorated adhesive and/or longtime use. The damage from the wear of the air chutes can create coke spillage occasionnally.

The Metal 7 team inspects the abrasion problems and identifies a proper application to replace the ceramic tiles. A replacement ceramic coating which has a durability and hardness of 70 Rockwell C is proposed. This new coating has been applied to the first air chute and has been placed in service since March 2001. A second unit has been completely fabricated and coated with the same in July 2001.

After 12 months in service, the operators have not observed a pressure loss in the air chute, which truly indicates that this new protective coating is providing the results required. This life cylce improvement has also incurred the following:

• By the elimination of the ceramic tiles, the weight has been reduced considerably. The new ceramic coating, which is very thin (0.24mm or 0.010" thick) which does not increase the weight of the chute.



• The deflector surface is more uniform compared to the previous ceramic tiles. This assures that there is an effeciency gained in the system performance and has been confirmed by Aluminerie Alouette.