Phosphorus is a very important nutrient for humans; it is essential for growth and development and helps the body absorb other minerals such as calcium and iron. As a result, phosphorus has been mined from the earth since ancient times and is still an important source of dietary and fertilizer phosphorus today.
Since the 19th century, phosphate rock—also known as ‘rock phosphate’—has become an increasingly important source of phosphorus for commercial and industrial use. Phosphate rock is sedimentary rock composed primarily of the mineral apatite, a calcium phosphate compound found in the form of fossils and the shells of maritime creatures like oysters, snails, and clams.
In general, phosphate rock contains between 20%-30% phosphorus pentoxide, making it the most concentrated source of phosphorus available. Most phosphate deposits in the world are sedimentary and occur in sedimentary basins like the Mississippi Valley in the United States, Russia’s Kola Peninsula, and Morocco’s Oued Ed-Dahab Basin. The remainder of the world’s phosphate deposits are igneous–found in the upper continental crust–and come from volcanic eruptions.
Mining phosphate rock is the most economical way to obtain phosphorus for commercial applications. Large-scale mining operations have been conducted for well over a century, first in the United States and more recently in Tunisia, Morocco, Mexico, and Algeria. All of these countries rely heavily on phosphate production; between them, they account for more than 80% of the world’s phosphate rock production.
The mining process begins with the removal of overburden—the material that covers the phosphate deposits. This is accomplished using bulldozers and other heavy machinery. The overburden is replaced when mining is finished and the land is restored to its former condition.
Once the overburden is removed, the phosphate ore is exposed and can be extracted. This ore is then crushed and screened to further reduce its size before transport to chemical production facilities. Here, the ore is processed using several operations including scrubbing, calcining, and grinding. Once the process is complete, the final product is a fine powder known as ‘phosphate rock’.
Phosphate rock has a variety of uses. It is used as a fertilizer in agricultural operations, as feed for livestock, and as a raw material for manufacturing products such as detergents, pharmaceuticals, and flame retardants. It is also used in the production of phosphoric acid, which is essential for creating phosphates that are used in aviation fuel, medicines, and foods. Finally, phosphate rock is used in the glass and ceramics industries.
Phosphorus is a vital nutrient that is essential for life and commercial production; without phosphate rock and its derivatives, many of the products we take for granted would not exist. As a result, phosphate rock must be mined sustainably in order to ensure a continued supply of this important resource.
