The use of greater than 50% alumina RTO heat recovery media also hampers silica oxide from adhering to and plugging the media above 1250F. Oxidized silica in the solid state adheres to the silica present in the heat recovery media. Simply put, the less silica in the media, the less availability for the converted silica fume to adhere.
While going above a true 50% alumina without an upstream collection device will extend the media’s life expectancy dramatically, it will not stop molten salts from eventually plugging and fusing to the media (especially when complicated with, and agglomerated to silica in the air stream). But with a minimum of 55% alumina, the added burden of plugging due to the destruction of the media, will be eliminated.