Trisodium Phosphate (TSP) Supplier South Africa

What Is Trisodium Phosphate?

Trisodium phosphate (Na₃PO₄, TSP) is a tribasic sodium salt of phosphoric acid — the fully neutralised form where all three acidic hydrogens of H₃PO₄ are replaced by sodium. It produces a strongly alkaline solution in water (pH ~12 at 1%), making it effective as a high-pH builder, cleaning agent, and pH control chemical. TSP is available in anhydrous form and as the dodecahydrate (Na₃PO₄·12H₂O) crystalline salt. It is widely used in boiler water treatment, heavy-duty industrial cleaning, surface preparation for painting, and as a food additive (E339iii) and pharmaceutical excipient.

Boiler Water Treatment

In boiler water pH control, TSP is used in coordinated phosphate treatment programmes to maintain boiler water pH in the range 10.5–11.5, preventing carbon steel corrosion (which increases below pH 9) while controlling calcium carbonate and calcium phosphate scale. TSP is the more alkaline phosphate source in these programmes (vs. DSP) and is used to adjust pH upward when the boiler pH drops below target. The phosphate also precipitates residual calcium hardness as a mobile hydroxyapatite sludge that is removed by blowdown. TSP is compatible with oxygen scavengers (sodium sulfite, hydrazine) and other boiler water additives.

Cleaning and Surface Preparation

In industrial and domestic cleaning, TSP is an effective heavy-duty cleaning agent for grease, oil, paint, mildew stains, and sooty deposits. Its high alkalinity (pH 12) saponifies fats and oils, suspends soil particles, and is effective without added surfactant. In surface preparation for painting, TSP degreases and etches surfaces, improving paint adhesion on both metal and wood substrates. In the food industry, TSP is used as an antimicrobial surface treatment for poultry carcasses (trisodium phosphate chiller immersion). Terracore Chemicals supplies TSP in 25 kg bags in technical and food grade.