Sodium tripolyphosphate

Sodium tripolyphosphate (STP, E451i, sodium triphosphate, pentasodium triphosphate) is an inorganic polyphosphate salt registered under CAS 7758-29-4. It is produced by high-temperature calcination of monosodium phosphate and disodium phosphate, yielding a condensed phosphate structure with strong sequestering and buffering capacity.

In detergent and cleaning formulations, STP binds calcium and magnesium ions through chelation, preventing scale formation and improving surfactant performance. In food processing, it functions as a moisture-retention agent and pH buffer in meat and seafood products. Water treatment applications rely on its ability to inhibit corrosion and control mineral precipitation in distribution systems.

STP is available in food-grade (E451i, FCC) and technical-grade forms, supplied as powder or granules. It is compliant with REACH regulations and listed under EC 231-838-7. Standard packaging includes 25 kg bags and bulk options, with documentation available for food, industrial, and water treatment applications.