Results of Trials with a Multi Stage Filtration System Employing a Cyclone

The development of a multi stage filter comprising a ceramic foam filter applied in a first chamber operating in cake mode; grain refiner added in a second chamber and a cyclone deployed in a final chamber to ensure removal of oxides and agglomerates arising from grain refiner addition was presented in TMS 2008. The first industrial prototype, installed at Trimet Aluminium at Essen in Germany, demonstrated that liquid metal could pass through the cyclone successfully without excessive turbulence or splashing. Initial difficulties in achieving the desired flow rate through the cyclone were overcome by increasing the head height difference to 150 mm and a flow rate of >20 t/h was achieved in testing on a sow casting station and reported at TMS 2011. In 2016 the program has been restarted and two further trials carried out on the Research Casting pit at Trimet. Podfa measurements of metal cleanliness before and after passing through the filter have been made together with analysis of the spent filter section. The results are reported in this paper.