Calcium sulfate produced by the reaction of
sulfuric acid with phosphate rock to produce phosphoric acid. Phosphogypsum
is a solid waste within the definition of Section 403.703(13), F.S.
The by-product of treating phosphate rock with
sulfuric acid. It also contains phosphate, fluorides, trace amounts of metals,
including radium. Chemically, hydrated calcium sulfate, the dihydrate being
the more common form, although hemihydrate is also produced. It's name distinguishes
it from natural or mined gypsum and and power plant gypsum from sulfur recovery.