An aerial view of a Phosphogypsum pond in Central Florida. U.S. production facilities utilize a wet process in which the prepared rock is treated with sulfuric acid to produce the phosphoric acid. Phosphoric acid is water soluble so it can be taken up by crops. It can also be concentrated, as desired, by evaporating water from the mixture.

The by-product remaining after the acid conversion is largely calcium sulfate and has been given the name phosphogypsum. (Gypsum is the common trade name for hydrated calcium sulfate, a common building material.)