Phosphoric Acid Overview
Phosphoric acid, also known as orthophosphoric acid or phosphoric(V) acid, is a mineral (inorganic) acid having the chemical formula H3PO4. Alternatively, orthophosphoric acid molecules can combine with themselves to form a variety of compounds referred to as phosphoric acids in a more general way. The term "phosphoric acid" can also refer to a chemical or reagent consisting of phosphoric acids, usually mostly orthophosphoric acid.
Phosphoric acid is a phosphorus-containing inorganic acid made up of phosphorus, oxygen, and hydrogen. In a broardened term, it includes the monomeric (orthophosphoric acid), dimeric (pyrophosphoric acid), and polymeric (metaphosphoric acid) forms of the acid. Phosphoric acid commonly indicates the monomeric form orthophosphoric acid.
Thermal phosphoric acid : This very pure phosphoric acid is obtained by burning elemental phosphorus to produce phosphorus pentoxide and dissolving the product in dilute phosphoric acid. This produces a very pure phosphoric acid, since most impurities present in the rock have been removed when extracting Phosphorus from the rock in a furnace. The end result is food grade, thermal phosphoric acid; however, for critical applications additional processing to remove arsenic compounds may be needed.
Wet phosphoric acid: Wet Process Phosphoric acid is prepared by adding sulfuric acid to calcium phosphate rock.
The simplified reaction is:
3H2SO4 + Ca3(PO4)2 + 6H2O ↔ 2H3PO4 + 3CaSO4.2H2O+ 6H2O
Wet process acid can be purified by removing fluorine to produce animal grade phosphoric acid or by solvent extraction and arsenic removal to produce food grade phosphoric acid.
Phosphoric acid is a phosphorus-containing inorganic acid made up of phosphorus, oxygen, and hydrogen. In a broardened term, it includes the monomeric (orthophosphoric acid), dimeric (pyrophosphoric acid), and polymeric (metaphosphoric acid) forms of the acid. Phosphoric acid commonly indicates the monomeric form orthophosphoric acid.
Preparation of phosphoric acid
Phosphoric acid can be prepared by two routes - the Thermal Process and the Wet Process.Thermal phosphoric acid : This very pure phosphoric acid is obtained by burning elemental phosphorus to produce phosphorus pentoxide and dissolving the product in dilute phosphoric acid. This produces a very pure phosphoric acid, since most impurities present in the rock have been removed when extracting Phosphorus from the rock in a furnace. The end result is food grade, thermal phosphoric acid; however, for critical applications additional processing to remove arsenic compounds may be needed.
Wet phosphoric acid: Wet Process Phosphoric acid is prepared by adding sulfuric acid to calcium phosphate rock.
The simplified reaction is:
3H2SO4 + Ca3(PO4)2 + 6H2O ↔ 2H3PO4 + 3CaSO4.2H2O+ 6H2O
Wet process acid can be purified by removing fluorine to produce animal grade phosphoric acid or by solvent extraction and arsenic removal to produce food grade phosphoric acid.
