Posted 1/20/2011 13:32 (#1560970 - in reply to #1560724) Subject: Re: Fly ash isn't flue gas gypsum.
Fly ash isn't flue gas gypsum. Fly ash is the solid results of burning coal, ashes.
Gypsum comes from treating stack gas with lime to gather sulfur fumes. The reaction makes gypsum, but depending on the fuel there can be heavy metals in that like mercury which I think is the most common.
Flue gas gypsum
