Fundamental models to support efficient aluminum alloys production

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In this proposed 3-year project, in collaboration with Rio Tinto Alcan, Alcoa, Hydro Aluminium and Constellium, we will extend and develop thermodynamic, phase equilibria and physical property models for Hall-Héroult cells applications. These models are necessary for a better understanding and advanced simulations of chemical and electro-chemical reactions, phase equilibria and the transport properties during electrolysis of alumina, liquid metal treatment, recycling to produce aluminum and high value alloys. Around three million tons of Al are produced in Hall-Héroult cells in Canada every year and the competition from Russia and China is very strong : the developed models will be integrated in the FactSage thermochemical software package and will provide a unique advantage to Canadian Al-producers. The proposed project is building on the previous NSERC-CRD Projects "A Virtual Laboratory for the Aluminum Industry" and "A Virtual Laboratory for Aluminum Reduction Cells", with the same industrial partners. It will be divided into 2 main themes with 2 sub-projects each : 1) Aluminum Electrolysis and 2) Alloys, Metal Treatments and Recycling. Theme 1) refers to bath additives and impurities, and their impact on energy efficiency, and also to cell materials. In particular, we will develop thermodynamic models involving the elements S, B, C and H, develop a new type of "predominance diagram" and a mass balance approach for the impurities, extend the modeling of the viscosity and electrical conductivity of the electrolyte with additives, explore the modeling of the surface tension of the base electrolyte, complete our existing phase equilibrium model for the dissolution of inert anodes elements, and extend the development of our new thermodynamic model for carbon and hydrogen in carbon crystallites (anodes). Theme 2) refers to the thermodynamic modeling of primary crystallization fields of intermetallics in the Al-rich corner, and also to advanced salt fluxes for efficient metal treatment and recycling. In particular, the Al-rich corner of the Al-Zr-Ti-V-Cr system will be considered, and salts containing BaSO4 and/or ZnCl2/ZnF2 will be taken into account.