Development of durable and efficient cathodes for primary aluminum production

PROJECT COST:

1 169 046 $

PRIMA CONTRIBUTION:

223 098 $

PROJECT DETAILS:

The lifetime of aluminum electrolysis cells is related principally to the speed of erosion (or degradation) of the graphite cathode blocks. The end of the cell’s lifetime is reached when the degradation front reaches the current busbars beneath the cathode blocks. To address this problem, the solution is to apply a protective coating on the surface of the cathode blocks. This will act as an infiltration barrier against cryolite and aluminum in the graphite blocks, making them more resistant to electrochemical degradation. These coatings must therefore have excellent resistance to corrosion and to mechanical and thermal shock. They will also need to have good wettability with respect to liquid aluminum, as well as excellent electrical conductivity, which will help reduce the energy consumption of the process. In addition, the best contact between the aluminum and the cathode blocks could reduce the formation of resistive deposits at this interface. Particularly, TiB₂ is a promising material, but its development into a dense and homogeneous coating poses many challenges. In this project, different deposition methods of TiB₂ to form coatings on the surface of cathode blocks will be evaluated, as well as their behavior under the conditions of aluminum electrolysis at the laboratory scale and then at the pilot scale. This project will improve the profitability of Quebec’s aluminum smelters, which must constantly improve their electrolysis process to compete with aluminum produced in the Middle East and Asia, where labour and energy costs are very attractive.
Through this project, one PhD student, one master’s student, one postdoctoral fellow, and six undergraduate fellows will be trained.