Chemical Properties
Phosphate rock is a sedimentary phosphate mineral composed primarily of carbonaceous fluoroapatite. Gangue minerals include quartz, chalcedony, calcite, dolomite, hydromica, kaolinite, glauconite, and organic matter. Its color ranges from yellowish-brown, greenish-brown, light gray, dark gray, or black. Its hardness is 2-4, and its density is 2.8-3.0 g/cm??. Carbonaceous fluoroapatite occurs in two forms: one is a microcrystalline or cryptocrystalline aggregate with a strawberry, grape, or crust-like appearance; the other is an amorphous or microcryptocrystalline aggregate with a colloidal appearance, commonly known as "collophane." The latter is the most common form of phosphorite. Carbonaceous fluoroapatite is difficult to identify with the naked eye. However, if a nitric acid solution containing ammonium molybdate is dripped onto phosphorite, a ginger-colored precipitate of ammonium phosphomolybdate appears. Marine phosphorite deposits are often large in scale and have great industrial value.
Uses
80%–90% of phosphate rock (such as Phosphate rock and Phosphorite, calcined) is used to manufacture phosphate fertilizers, common varieties of which include: superphosphate, triple superphosphate, calcium magnesium phosphate, nitrate phosphate, ammonium phosphate, precipitated calcium phosphate (dicalcium phosphate), phosphate rock powder fertilizer, and other phosphorus-containing compound fertilizers. The remainder is used to manufacture yellow phosphorus, red phosphorus, phosphoric acid, phosphates, and other phosphates; these products are widely used in chemical, pharmaceutical, food, defense, dye, detergent, match, sugar refining, metallurgy, textile, glass, ceramics, pesticide, feed, and water treatment industries.
Definition
Substance obtained by heating naturally occurring phosphate rock to 732.degree.C to 816.degree.C (1350.degree.F to 1500.degree.F) in a fluidized bed or other suitable device for oxidizing carbonaceous matter. Characterized by upgraded phosphorus content and reduced hydrocarbon levels.
Agricultural Uses
Phosphorite or mineral phosphate is made by grinding
rock phosphate, a natural mineral found in the form of
sedimentary rocks containing various calcium phosphates.
It is used as a phosphatic fertilizer, and is a primary
source of phosphorus. It is a mineral containing calcium
phosphate with hydroxyl groups or is hydroxy apatite.
Phosphorite is a continental phosphatic rock,
consisting of concretions of collophanite, found in
decalcification clays. The most famous phosphorites are
from Causses du Quercy (France).
