HEDP·Na4, Hydroxy Ethylidene Diphosphonic Tetrasodium


HEDP·Na4 is the tetrasodium salt of hydroxy ethylidene diphosphonic acid. This HEDP tetrasodium is a good scale inhibitor for calcium carbonate. HEDP·Na4 can be used in low-pressure boiler water systems, circulating water systems, industrial and municipal cleaning water systems, and swimming pools.

The solid HEDP·Na4 is a white powder, soluble in water, easily deliquescence, suitable for use in winter and freezing districts. It is a kind of organophorphonic acid scale and corrosion inhibitor, can form a stable complex with Fe, Cu, and Zn ions, it can dissolve the oxides on a metal surface, it has good scale and corrosion inhibition effect under 250℃.

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Structure Formula:

HEDP·Na4 structure formula


AppearanceColorless to yellowish transparent liquidWhite powder
Active content (HEDP), %20.3-21.756.0 Min.
Active content (HEDP·Na4), %29.0-31.079.9 Min.
pH (1% water solution)10.0-12.0 (as it)11.0-12.0
Density (20℃), g/cm31.26-1.36
Phosphoric acid (PO43-), %18.4-20.452.0 Min.
Fe, mg/L20.0 Max.35 Max.
Moisture, %15 Max.
Phosphorous Acid, %1.0 Max.
Colour, APHA50.0 Max.


HEDP·Na4 is widely used in circulating cool water systems, medium and low-pressure boiler, oil field water pipelines as scale and corrosion inhibitor in fields such as electric power, chemical industry, metallurgy, fertilizer, etc. In the light woven industry, HEDP tetrasodium is used as a detergent for metal and nonmetal. In the dyeing industry, HEDP·Na4 is used as a peroxide stabilizer and dye-fixing agent; In non-cyanide electroplating, HEDP tetrasodium is used as a chelating agent.

Packing and Storage:

Liquid: 200L plastic drum, IBC(1000L), customers’ requirement.

200l plastic drum 1000l IBC

Solid: 25kg/bag, customers’ requirement. Storage for ten months in shady room and dry place.

25kg paper bags

Safety Protection:

Weak acidity, Avoid contact with eye and skin. Once contacted, flush with water.


HEDP tetrasodium salt, Dequest 2016, Tetra-sodium hydroxyethyl diphosphonate.


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