Reply to Discussion of “Characterization of Ceramic Foam Filters Used for Liquid Metal Filtration” and “Electromagnetically Modified Filtration of Aluminum Melts: Part I. Electromagnetic Theory and 30 PPI Ceramic Foam Filter Experimental Results”
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The focus of the current study has been on the filtration of particulates in aluminum cast house operations and not in foundry casting. The Remelting and Inclusion Refining of Aluminum project (RIRA) was conducted in coordination with industrial partners (Alcoa, Norsk Hydro, and Sapa) and addressed their desire to remove very fine particulates (down to 10 μm) for high performance applications.
The filter sizes used in aluminum cast houses are of the order of 20 to 50 pores per inch (PPI) and the typical “free space” casting velocities are in the range of 0.2 to 1.5 cm/s, as recommended by one filter manufacturer. Filtration efficiency is known to be inversely related to velocity and positively correlated with higher filter PPIs. Lower velocities and tighter filters are typically applied to the higher quality grades. Low velocities (<1 cm/s) and “tight” filters (30 to 80 PPI) were, therefore, selected by the current authors as being consistent with the goal of improving filtration...
KeywordsLorentz Force Filtration Efficiency Aluminum Melt Ceramic Foam Filter Effective Electrical Conductivity
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