Uses of phosphoric acid

Phosphoric acid is not only an inorganic acid, but also a medium-strong acid. We can get this phosphoric acid by dissolving hot water with phosphorus pentoxide. Phosphoric acid has a wide range of uses. It can be used not only in industry, but also in food, fertilizers, food additives and many other fields. If you don’t know it yet, let’s take a look at the detailed uses of phosphoric acid, right?

First, the uses of phosphoric acid. Agriculture: Phosphoric acid is the raw material for producing important phosphate fertilizers (superphosphate, potassium dihydrogen phosphate, etc.), and is also the raw material for producing feed nutrients (monocalcium phosphate). Industry: Phosphoric acid is an important chemical raw material. Its main functions are as follows: treating metal surfaces and forming insoluble phosphate films on the metal surfaces to protect the metals from corrosion. Mixed with nitric acid as a chemical polishing agent to improve the finish of metal surfaces. Phosphate esters are raw materials for producing detergents and pesticides. Raw materials for producing phosphorus-containing flame retardants. Food: Phosphoric acid is a food additive. It is used as an acidulant and yeast nutrient in food. Coca-Cola contains phosphoric acid. Phosphates are also important food additives that can serve as nutritional enhancers. Medicine: Phosphoric acid can be used to prepare phosphorus-containing drugs, such as sodium glycerophosphate.

Second, the production process of phosphoric acid has always been affected by the region of raw materials. The production of phosphoric acid in my country is mainly concentrated in Yunnan, Sichuan, Guizhou and Hubei, while the refined application of phosphoric acid is mainly concentrated in coastal areas. According to a survey report from the China Phosphorus Exchange, my country's phosphoric acid production is mainly based on thermal phosphoric acid, which purifies high-purity phosphoric acid to meet industrial needs.

Orthophosphoric acid is a phosphoric acid composed of a single phosphorus-oxygen tetrahedron. In the phosphoric acid molecule, the P atom is sp3 hybridized, and three σ bonds are formed between the three hybrid orbitals and the oxygen atoms. The other P-O bond is composed of a σ bond from phosphorus to oxygen and two d-pπ bonds from oxygen to phosphorus. The σ bond is formed when a lone pair of electrons on the phosphorus atom coordinates to the empty orbital of the oxygen atom. The d←p bond is formed by the overlap of two pairs of lone pairs of electrons in the py and pz orbitals of the oxygen atom and the empty dxz and dyz orbitals of the phosphorus atom. Since the 3d energy level of the phosphorus atom is much higher than the 2p energy level of the oxygen atom, the formed molecular orbital is not very effective, so the P-O bond is a triple bond in terms of number, but is between a single bond and a double bond in terms of bond energy and bond length. There are hydrogen bonds in both pure H3PO4 and its crystalline hydrates, which may be the reason why concentrated phosphoric acid solutions are viscous.