Phosphoric Acid

Phosphoric acid, also known as orthophosphoric acid, is a common inorganic acid, a medium-strong acid,

easily volatile, difficult to be decomposed and almost not oxidized. 

It shares the commonality of acids and belongs to the ternary weak acid. Its acidity is lower than HCl, 

sulfuric acid and nitric acid, but higher than both boric acid and acetic acid. 

Phosphoric acid is prone to dehydration in air. Loss of water by heat generates pyrophosphoric acid, 

then loss of water generates metaphosphoric acid.

Cas 7664-38-2 | Phosphoric AcidCas 7664-38-2 molecular formula

Synonyms: Orthophosphoric Acid

Molecular formula: H3PO4

Molecular weight: 98.00

HS code: 28092011

CAS NO.: 7664-38-2

Category: Industrial Cleanning, Water treatment, Food & Feed ingredients


1) Treat metal surface, generate insoluble phosphate film on metal surface, protect metal from corrosion.

2) Mixed with nitric acid as chemical polishing agent to improve the finish of metal surface.

3) Producing raw material phosphate for detergents and pesticides.

4) Raw material for the production of phosphorus-based flame retardants.

5) Food additives additives.


35KG Drums, 330KG Drums, 1650KG IBC

Cas 7664-38-2 Phosphoric Acid PackagingCas 7664-38-2 Phosphoric Acid Packaging


How is phosphoric acid made?

Phosphoric acid is usually prepared by several methods, the most common of which include wet and dry methods. The wet method is mainly obtained by acid treatment of phosphate rock, while the dry method is to obtain phosphoric acid by burning phosphate rock at high temperature.

In the wet method, the preparation of phosphoric acid mainly involves extracting phosphorus compounds from phosphate rock and extracting phosphoric acid from the reaction solution, usually through precipitation or evaporation concentration. The extracted phosphoric acid is further refined and crystallized to obtain higher purity phosphoric acid. On the other hand, the dry method mainly burns phosphate rock at high temperature to generate phosphorus oxide, which then reacts with water to form phosphoric acid. This process is generally less common because wet methods are more economical and environmentally friendly.

What is the difference between orthophosphoric acid and phosphoric acid?

Orthophosphoric acid and phosphoric acid actually refer to the same compound - phosphoric acid. The two terms can be used interchangeably without substantial difference. Phosphoric acid is an inorganic acid in which one phosphorus atom is bonded to three hydrogen atoms through three oxygen atoms. Sometimes, people may use the term "orthophosphoric acid" to emphasize that this is the most basic form of phosphoric acid, to distinguish it from other phosphoric acid derivatives that contain more phosphorus oxides, such as phosphorous acid (HPO₄²⁻) and hypophosphorous acid (H₂PO₄⁻ ). This distinction is used primarily when discussing the different ionic forms of phosphoric acid, rather than when describing the compound itself. Therefore, in short, orthophosphoric acid and phosphoric acid are two names for the same compound, and there is no essential difference.

What is the function of phosphoric acid?


In the food and beverage industry, especially in the production of soft drinks, phosphoric acid acts as an acidifier, providing rich flavor and balancing sweetness.

●Fertilizer production:

Phosphoric acid is a key ingredient in the production of phosphate fertilizers. It reacts with phosphate rock to produce a water-soluble fertilizer that provides plants with essential phosphorus.

●Metal surface treatment:

Phosphoric acid is used in metal cleaning and rust removal, as a cleaning agent and as a surface treatment agent. It helps remove rust and prepares the metal surface for further treatments such as painting or coating.


In dentistry, phosphoric acid is used as an etchant. It is applied to the tooth surface to create tiny irregularities that improve the adhesion of dental materials such as adhesives and composites.

●pH adjustment:

Phosphoric acid is used to adjust pH during water treatment. It helps maintain the pH required for various reactions and processes.

●Chemical manufacturing:

Phosphoric acid is used as a reactant in the production of various chemicals and pharmaceuticals. It participates in synthetic reactions to form different compounds.

●Textile and Leather Industry:

In textile and leather processing, phosphoric acid is used in dyeing and finishing processes to contribute to the overall handling and coloring of the material.

●Anti-corrosion protection:

Acts as a rust inhibitor, providing a protective coating on metal surfaces to help prevent corrosion and degradation over time.


Appearance/Transparent colorlessSticky liquid
Assay as(H3PO4)%≥85.0
Arsenic as Asmg/kg≤0.5
Fluoride as Fmg/kg≤10
Heavy metals as Pbmg/kg≤1
Reductive Matter as H3PO3mg/kg≤120
Sulphate as SO4mg/kg≤50
Contact us for full parameters

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