Phosphogypsum

Phosphogypsum is a type of geological material made from the waste created when phosphate rocks are processed to make fertilizer. When phosphate rocks are processed, the byproduct is a sulfuric acid-water mixture called phosphoric acid. This mixture is then dried to form solid phosphogypsum. Phosphogypsum is mainly made of gypsum, a soft mineral made up of calcium sulfate, with trace amounts of other minerals and dust particles. It is often used as a soil amendment, a material that is added to the soil in order to improve its properties and make it more suitable for plant growth. Phosphogypsum can also be used to make wallboard, plaster, and other construction materials.