FEA study of the electrodeposition of Al from ILs: definition of a pilot plant model for an industrial scale-up.Tuesday (27.09.2016) 12:00 - 12:15 Part of:
ILs offer a variety of advantages over aqueous electrolytes. In general ILs show large chemical and thermal stability, high ionic conductivity and an electrochemical window much larger than water. Thus enabling the effective electrodeposition of some very non-noble metals, such as Al, Nb and Ti. Still, the use of ionic liquids as electrolyte constitutes a challenging quest for galvanic industry due to their peculiar transport proprieties. The main objective of this work is to formalize a complete computational model suitable for the description of the electrodeposition process of Al from BMIMCl/AlCl3(1:1.5) taking into consideration a time-dependent model of the process. A common approach in this field is constituted by the Finite Elements Analysis (FEA), which is a strategy to solve the governing partial differential equations by means of a suitable discretization of the domains involved in the process. Respect to the previous approaches, in this communication the electrochemical kinetics and relevant chemical equilibria as well as the transport phenomena, were modelled at very high level of theory. Taking into account all the parameters affecting the galvanic process, including turbulent convection fields. In particular, we considered tertiary current distribution, the chemical equilibria of the dimer formation and turbulence models to assess the velocity field in galvanic bath, in order to assess the electrodeposited layer thickness even on sharp edges.
After a critical analysis of the relative effects of the different contributions to the model a validation was carried at a lab scale, through the comparison with experimental data. The experimental thickness of the Al film was reckoned for a Rotating Hull Cylinder (RHC) apparatus and in for a simple electrodeposition experiment on a small disk. The model will be useful to design parts of a future pilot plant for this process.