Phosphogypsum

Phosphogypsum refers to the calcium sulfate hydrate formed as a by-product of the production of fertilizer from phosphate rock. It is mainly composed of gypsum. Although gypsum is a widely used material in the construction industry, phosphogypsum is usually not used, but is stored indefinitely because of its weak radioactivity caused by the presence of naturally occurring uranium and thorium, and their daughter isotopes radium, radon, polonium, etc. The long-range storage is controversial. Somewhere between 100,000,000 and 280,000,000 tons are estimated to be produced annually as a consequence of the processing of phosphate rock for the production of phosphate fertilizers.