Phosphoric acid is produced industrially by two general routes - the thermal process and the wet process. Thermal process is purer and more expensive. The wet process dominates in the commercial sector, and the thermal process is used in the food industry.
Burn elemental phosphorus to produce phosphorus pentoxide and dissolved in dilute phosphoric acid can produce a very pure phosphoric acid. The thermal process is used as food-grade as most impurities present in the rock have been removed.
It has a wide range of use, such as a rust converter, food additive, dental and orthopedic etchant, electrolyte, fertilizer feedstock, soldering flux, industrial etchant, component of home cleaning products, and dispersing agent. What's more, it is used in dentistry and orthodontics in medicine.
Phosphoric acid E338 is food grade additives, which is used to acidify foods and beverages. It provides a tangy or sour taste like colas. Food grade E338 uses in a variety of food products, such as cheese, bakery products, yeast, jams, jellies and refined sugar.
85% aqueous solution is the most common source of phosphoric acid. Its solutions are colourless, odourless, and non-volatile. Besides, it is a syrupy liquid but still pourable.
Is it safe for use?
Phosphoric acid, 85 wt.% is considered a corrosive chemical solution. People should fully aware of its hazards and safe handling measures. It is recommended that serious precautions should be took to prevent the generation of mists so that to avoide potentially hazardous exposure to eyes, skin, and nasal passageways. Proper storage and avoid leaks, make sure any solid material is kept dry and avoid reuse containers.