THERMO-ELECTRO-MECHANICAL MODELING OF A HALL-HÉROULT CELL COKE-BED PREHEATING
Daniel Richarda, Patrice Gouletb, Marc Dupuisc, Jérôme Bédardb and Mario Fafardb
aHatch, 5 Place Ville Marie, Bureau 200
Montréal, Québec, Canada, H3B 2G2
bLaval University, Science and Engineering Faculty,
Adrien-Pouliot Building, Sainte-Foy (Québec),
Canada, G1K 7P4
cGéniSim Inc., 3111 rue Alger,
Jonquière Québec, Canada, G7S 2M9
ABSTRACT
Start-up of a Hall-Héroult cell is a delicate task that can affect pot performance and pot life.
Modern practices for high amperage cells involve preheating the lining before the molten
electrolyte is poured in. Different preheating methods and heat-up schedules are used
throughout the industry, and the optimum between a short start-up and damage minimization to
the cell is elusive.
Direct electrical coke-bed preheating is one of the most common techniques. This practice
typically results in a non-uniform surface temperature distribution and can generate detrimental
thermal gradients in the cathode blocks. Numerical modeling is an invaluable tool to study this
complex problem and can help improve the preheating procedures.
The modeling of the mechanical response of the lining is critical to detect risks of cathode block
cracking or the development of gaps where liquids could leak into. Taking into account the
baking of ramming paste, the quasi-brittle nature of carbon and the contact interfaces between
different materials are examples of key elements to consider.
A finite element slice model of a cell was built and simulations of different electrical preheating
scenarios were performed using the in-house code FESh++ to demonstrate what can be
learned through thermo-chemo-mechanical modeling. The potential industrial application of the
model is discussed.