PHOSPHORIC ACID

~ also known as Orthophosphoric Acid; O-Phosphoric acid; 7664-38-2; Phosphoric(V) Acid); Sonac; Phosphorsaeure; etc. is a colorless, odorless phosphorus-containing inorganic acid. The global phosphoric acid market during 2017 to 2022 is projected to exceed US$ 30,000 Mn by 2022 end, at a CAGR of 3.4%.

Chemical structure:  H₃PO₄ or H₃O₄P. It is a phosphorus-containing inorganic acid.

Properties: Phosphoric acid is a clear colorless liquid or clear crystalline solid. The pure solid melts at a temperature of 42.35°C. It has a density of 1.834 g/cm³. The liquid form is typically an 85% aqueous solution. It is shipped as both liquid and solid. It is corrosive to tissue and metals. Phosphoric acid is used to make detergents and fertilizers and has wide application in food processing. It is soluble in water, alcohol, and ether.

Phosphoric acid is prepared in the industry through two general routes; the thermal process and the wet process. The wet process is mostly used in the commercial sector. The thermal process, on the other hand, is more expensive. However, it produces a purer product, which is mostly used in the food industry.

In the wet process, the addition of sulfuric acid to tricalcium phosphate rock, typically found in nature as apatite, produce phosphoric acid. The reaction is:

Ca₅(PO₄)₃X + 5 H₂SO₄ + 10 H₂O → 3 H₃PO₄ + 5 CaSO₄·2 H₂O + HX

Where X can include F, Cl, Br, and OH,

In this process, very pure phosphoric acid is prepared by burning phosphorus to produce phosphorus pentoxide, which is afterward dissolved in dilute phosphoric acid. This route generates a very pure phosphoric acid, since most impurities available in the rock have been removed. The resultant product is a food-grade, thermal phosphoric acid.

Chemical reactions and Uses: Phosphoric acid is a sequestering agent, which binds various divalent cations, including Ca++, Fe++, Cu++, and Mg++. Orthophosphoric acid molecules may combine with themselves to form a range of compounds referred generally to as phosphoric acids.

Phosphoric acid has a wide range of applications including; agricultural chemicals (non-pesticidal), abrasives, adsorbents and absorbents, finishing agents, flame retardants, corrosion inhibitors and anti-scaling agents, dyes, fuels and fuel additives, processing aids, solvents (for cleaning or degreasing), intermediates, laboratory chemicals, oxidizing/reducing agents, solvents (which become part of product formulation or mixture), plating agents and surface treating agents, and surface active agents.

Other uses include; batteries, building/construction materials (wood and engineered wood products), electrical and electronic products, cleaning and furnishing care products, explosive materials, laundry and dishwashing products, paints and coatings, paper products, metal products, personal care products, plastic and rubber products, photographic supplies, film, photo-chemicals, and water-treatment products.