phosphorite
Sign in to savethumb|Peloidal phosphorite, Phosphoria Formation, Simplot Mine, Idaho. 4.6 cm wide. thumb|Fossiliferous peloidal phosphorite, (4.7 cm across), Yunnan, [[China. ]] Phosphorite, phosphate rock or rock phosphate is a non-detrital sedimentary rock that contains high amounts of phosphate minerals. The phosphate content of phosphorite (or grade of phosphate rock) varies greatly, from 4% to 20% phosphorus pentoxide (P2O5). Marketed phosphate rock is enriched ("beneficiated") to at least 28%, often more than 30% P2O5. This occurs through washing, screening, deliming, magnetic separation or flotation.
Article
11 sectionsContents
- Classification of phosphatic sedimentary rocks
- Phosphorus cycle, formation and accumulation
- Depositional environments
- Types of phosphorite deposition
- Tectonic and oceanographic settings of marine phosphorites
- Production and use
- Production
- Uses
- See also
- References
- External links
thumb|Peloidal phosphorite, Phosphoria Formation, Simplot Mine, Idaho. 4.6 cm wide. thumb|Fossiliferous peloidal phosphorite, (4.7 cm across), Yunnan, [[China. ]] Phosphorite, phosphate rock or rock phosphate is a non-detrital sedimentary rock that contains high amounts of phosphate minerals. The phosphate content of phosphorite (or grade of phosphate rock) varies greatly, from 4% to 20% phosphorus pentoxide (P2O5). Marketed phosphate rock is enriched ("beneficiated") to at least 28%, often more than 30% P2O5. This occurs through washing, screening, deliming, magnetic separation or flotation. By comparison, the average phosphorus content of sedimentary rocks is less than 0.2%.
The phosphate is present as fluorapatite Ca5(PO4)3F typically in cryptocrystalline masses (grain sizes 5(PO4)3OH or Ca10(PO4)6(OH)2, which is often dissolved from vertebrate bones and teeth. In contrast, fluorapatite can originate from hydrothermal veins. Other sources also include chemically dissolved phosphate minerals from igneous and metamorphic rocks. Phosphorite deposits often occur in extensive layers, which cumulatively cover tens of thousands of square kilometres of the Earth's crust.