ELECTROMAGNETIC STIRRING IN ALUMINIUM LADLES

Electromagnetic stirring (AL-EMS) in aluminium melting and holding furnaces is now a well-established technology to enhance chemical and thermal homogeneity and to reduce cycle time, energy consumption and dross formation. This paper will discuss the benefits of using AL-EMS for ladle stirring of liquid aluminium. To become more cost efficient some foundries are purchasing liquid aluminium. By doing so, a reduction of material losses together with savings in energy and logistic costs, as well as current assets, can be achieved. The molten aluminium is stored in ladies which can be put on hold for as long as 24 hours before being delivered to the foundry. Heating and therefore stirring will be needed to assure correct temperature during this waiting time. Experiences from industrial plant trials have shown that electromagnetic stirring can generate total thermal homogenization in aluminium ladles. Reduction of melt surface temperature by AL-EMS and how this can suppress surface oxidation and improve heat transfer to the melt is discussed in this paper. This further demonstrates the potential of Al-EMS to reduce burner running cost. AL-EMS also assures a high melt quality resulting from the minimization of thermal gradients.