REMOVAL OF SOLID INCLUSIONS FROM MOLTEN ALUMINIUM THROUGH CERAMIC FOAM FILTRATION

摘要

A CFF (ceramic foam filter) is commonly found in aluminium cast houses as a final inline melt treatment step before casting. An analytical model to predict the inclusion removal efficiency of a ceramic foam filter has been derived and verified against practical measurements. The model is based on an analogy to the removal of solid particles from a liquid by means of flotation and consists of a simple exponential function of particle size, filter pore size and filtration depth. However, the effects of the melt flow velocity, total inclusion load and the presence of grain refiner amongst that of other factors on the operational performance of the CFF have also been studied. It was found that the behaviour of a CFF becomes unpredictable with respect to any model currently available from the literature for certain conditions. This is especially observed for high flow rates and coarse filters.