The mechanism and kinetics of alloy filtration

This paper presents theoretical considerations on the mechanism and kinetics of liquid metal filtration as it is used in the refining of aluminium and ferrous alloys. The mechanisms are: adherence and sintering of inclusions to the filter surface; chemical reaction between the inclusion and the filter surface; and precipitation of secondary inclusions due to the drop in temperature when the liquid alloy flows through the filter. Of these the first mechanism is considered to be the most important as a source of inclusions in the material being refined. The second mechanism is useful to the refining process in that it reduces the amount of inclusions, and the third mechanism can be avoided by preheating the filter.