Typical phosphorites are argillaceous to sandy marine sedimentary rocks that contain stratified concentrations of calcium phosphate, mainly as apatite. Depending on the extraction process, the principal commodity obtained from these deposits is elemental phosphorus or phosphoric acid.

Byproducts may include the following commodities: uranium is commonly present in sedimentary phosphate and can be recovered in acid extraction; vanadium is a byproduct of electric furnace production of elemental phosphorus, where it can be recovered from the ferrophosphorus slag; fluorine can be recovered from waste gases and as fluorosilicic acid in the wet, or acid, process. Large quantities of impure calcium sulphate (phosphogypsum) are produced in the wet process; small amounts of this are used directly as a soil conditioner in the U.S.A., but the remainder constitutes a major disposal problem. The coproducts ferrophosphorus and calcium-silicate slag are produced in the thermal reduction of phosphate rock; some of the ferrophosphorus can be used as a ferro-alloy in the steel industry. The calcium-silicate slag, normally a waste product, can be crushed and used as a concrete aggregate, as ballast in highway or railroad construction, or can be foamed to form lightweight aggregate or slag wool (Christie, 1978b; Notholt et al., 1979).

Nomenclature is used in this paper as follows: phosphate is an informal term used in the industry to describe a rock, mineral, or salt containing phosphorus compounds. The term phosphate rock serves both industry and the geological fraternity, but with differing meanings. In the industry, phosphate rock is usually a high grade phosphate product that can be used in a fertilizer plant or put directly on cropland. It may also be beneficiated ore.